/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1993, 2010, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 * Copyright 2016 Gary Mills
 * Copyright 2019 Joyent, Inc.
 */

/*
 * VM - Hardware Address Translation management for Spitfire MMU.
 *
 * This file implements the machine specific hardware translation
 * needed by the VM system.  The machine independent interface is
 * described in <vm/hat.h> while the machine dependent interface
 * and data structures are described in <vm/hat_sfmmu.h>.
 *
 * The hat layer manages the address translation hardware as a cache
 * driven by calls from the higher levels in the VM system.
 */

#include <sys/types.h>
#include <sys/kstat.h>
#include <vm/hat.h>
#include <vm/hat_sfmmu.h>
#include <vm/page.h>
#include <sys/pte.h>
#include <sys/systm.h>
#include <sys/mman.h>
#include <sys/sysmacros.h>
#include <sys/machparam.h>
#include <sys/vtrace.h>
#include <sys/kmem.h>
#include <sys/mmu.h>
#include <sys/cmn_err.h>
#include <sys/cpu.h>
#include <sys/cpuvar.h>
#include <sys/debug.h>
#include <sys/lgrp.h>
#include <sys/archsystm.h>
#include <sys/machsystm.h>
#include <sys/vmsystm.h>
#include <vm/as.h>
#include <vm/seg.h>
#include <vm/seg_kp.h>
#include <vm/seg_kmem.h>
#include <vm/seg_kpm.h>
#include <vm/rm.h>
#include <sys/t_lock.h>
#include <sys/obpdefs.h>
#include <sys/vm_machparam.h>
#include <sys/var.h>
#include <sys/trap.h>
#include <sys/machtrap.h>
#include <sys/scb.h>
#include <sys/bitmap.h>
#include <sys/machlock.h>
#include <sys/membar.h>
#include <sys/atomic.h>
#include <sys/cpu_module.h>
#include <sys/prom_debug.h>
#include <sys/ksynch.h>
#include <sys/mem_config.h>
#include <sys/mem_cage.h>
#include <vm/vm_dep.h>
#include <sys/fpu/fpusystm.h>
#include <vm/mach_kpm.h>
#include <sys/callb.h>

#ifdef  DEBUG
#define SFMMU_VALIDATE_HMERID(hat, rid, saddr, len)                     \
        if (SFMMU_IS_SHMERID_VALID(rid)) {                              \
                caddr_t _eaddr = (saddr) + (len);                       \
                sf_srd_t *_srdp;                                        \
                sf_region_t *_rgnp;                                     \
                ASSERT((rid) < SFMMU_MAX_HME_REGIONS);                  \
                ASSERT(SF_RGNMAP_TEST(hat->sfmmu_hmeregion_map, rid));  \
                ASSERT((hat) != ksfmmup);                               \
                _srdp = (hat)->sfmmu_srdp;                              \
                ASSERT(_srdp != NULL);                                  \
                ASSERT(_srdp->srd_refcnt != 0);                         \
                _rgnp = _srdp->srd_hmergnp[(rid)];                      \
                ASSERT(_rgnp != NULL && _rgnp->rgn_id == rid);          \
                ASSERT(_rgnp->rgn_refcnt != 0);                         \
                ASSERT(!(_rgnp->rgn_flags & SFMMU_REGION_FREE));        \
                ASSERT((_rgnp->rgn_flags & SFMMU_REGION_TYPE_MASK) ==   \
                    SFMMU_REGION_HME);                                  \
                ASSERT((saddr) >= _rgnp->rgn_saddr);                    \
                ASSERT((saddr) < _rgnp->rgn_saddr + _rgnp->rgn_size);   \
                ASSERT(_eaddr > _rgnp->rgn_saddr);                      \
                ASSERT(_eaddr <= _rgnp->rgn_saddr + _rgnp->rgn_size);   \
        }

#define SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp, rgnp, rid)             \
{                                                                       \
                caddr_t _hsva;                                          \
                caddr_t _heva;                                          \
                caddr_t _rsva;                                          \
                caddr_t _reva;                                          \
                int     _ttesz = get_hblk_ttesz(hmeblkp);               \
                int     _flagtte;                                       \
                ASSERT((srdp)->srd_refcnt != 0);                        \
                ASSERT((rid) < SFMMU_MAX_HME_REGIONS);                  \
                ASSERT((rgnp)->rgn_id == rid);                          \
                ASSERT(!((rgnp)->rgn_flags & SFMMU_REGION_FREE));       \
                ASSERT(((rgnp)->rgn_flags & SFMMU_REGION_TYPE_MASK) ==  \
                    SFMMU_REGION_HME);                                  \
                ASSERT(_ttesz <= (rgnp)->rgn_pgszc);                    \
                _hsva = (caddr_t)get_hblk_base(hmeblkp);                \
                _heva = get_hblk_endaddr(hmeblkp);                      \
                _rsva = (caddr_t)P2ALIGN(                               \
                    (uintptr_t)(rgnp)->rgn_saddr, HBLK_MIN_BYTES);      \
                _reva = (caddr_t)P2ROUNDUP(                             \
                    (uintptr_t)((rgnp)->rgn_saddr + (rgnp)->rgn_size),  \
                    HBLK_MIN_BYTES);                                    \
                ASSERT(_hsva >= _rsva);                                 \
                ASSERT(_hsva < _reva);                                  \
                ASSERT(_heva > _rsva);                                  \
                ASSERT(_heva <= _reva);                                 \
                _flagtte = (_ttesz < HBLK_MIN_TTESZ) ? HBLK_MIN_TTESZ : \
                        _ttesz;                                         \
                ASSERT(rgnp->rgn_hmeflags & (0x1 << _flagtte));         \
}

#else /* DEBUG */
#define SFMMU_VALIDATE_HMERID(hat, rid, addr, len)
#define SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp, rgnp, rid)
#endif /* DEBUG */

#if defined(SF_ERRATA_57)
extern caddr_t errata57_limit;
#endif

#define HME8BLK_SZ_RND          ((roundup(HME8BLK_SZ, sizeof (int64_t))) /  \
                                (sizeof (int64_t)))
#define HBLK_RESERVE            ((struct hme_blk *)hblk_reserve)

#define HBLK_RESERVE_CNT        128
#define HBLK_RESERVE_MIN        20

static struct hme_blk           *freehblkp;
static kmutex_t                 freehblkp_lock;
static int                      freehblkcnt;

static int64_t                  hblk_reserve[HME8BLK_SZ_RND];
static kmutex_t                 hblk_reserve_lock;
static kthread_t                *hblk_reserve_thread;

static nucleus_hblk8_info_t     nucleus_hblk8;
static nucleus_hblk1_info_t     nucleus_hblk1;

/*
 * Data to manage per-cpu hmeblk pending queues, hmeblks are queued here
 * after the initial phase of removing an hmeblk from the hash chain, see
 * the detailed comment in sfmmu_hblk_hash_rm() for further details.
 */
static cpu_hme_pend_t           *cpu_hme_pend;
static uint_t                   cpu_hme_pend_thresh;
/*
 * SFMMU specific hat functions
 */
void    hat_pagecachectl(struct page *, int);

/* flags for hat_pagecachectl */
#define HAT_CACHE       0x1
#define HAT_UNCACHE     0x2
#define HAT_TMPNC       0x4

/*
 * Flag to allow the creation of non-cacheable translations
 * to system memory. It is off by default. At the moment this
 * flag is used by the ecache error injector. The error injector
 * will turn it on when creating such a translation then shut it
 * off when it's finished.
 */

int     sfmmu_allow_nc_trans = 0;

/*
 * Flag to disable large page support.
 *      value of 1 => disable all large pages.
 *      bits 1, 2, and 3 are to disable 64K, 512K and 4M pages respectively.
 *
 * For example, use the value 0x4 to disable 512K pages.
 *
 */
#define LARGE_PAGES_OFF         0x1

/*
 * The disable_large_pages and disable_ism_large_pages variables control
 * hat_memload_array and the page sizes to be used by ISM and the kernel.
 *
 * The disable_auto_data_large_pages and disable_auto_text_large_pages variables
 * are only used to control which OOB pages to use at upper VM segment creation
 * time, and are set in hat_init_pagesizes and used in the map_pgsz* routines.
 * Their values may come from platform or CPU specific code to disable page
 * sizes that should not be used.
 *
 * WARNING: 512K pages are currently not supported for ISM/DISM.
 */
uint_t  disable_large_pages = 0;
uint_t  disable_ism_large_pages = (1 << TTE512K);
uint_t  disable_auto_data_large_pages = 0;
uint_t  disable_auto_text_large_pages = 0;

/*
 * Private sfmmu data structures for hat management
 */
static struct kmem_cache *sfmmuid_cache;
static struct kmem_cache *mmuctxdom_cache;

/*
 * Private sfmmu data structures for tsb management
 */
static struct kmem_cache *sfmmu_tsbinfo_cache;
static struct kmem_cache *sfmmu_tsb8k_cache;
static struct kmem_cache *sfmmu_tsb_cache[NLGRPS_MAX];
static vmem_t *kmem_bigtsb_arena;
static vmem_t *kmem_tsb_arena;

/*
 * sfmmu static variables for hmeblk resource management.
 */
static vmem_t *hat_memload1_arena; /* HAT translation arena for sfmmu1_cache */
static struct kmem_cache *sfmmu8_cache;
static struct kmem_cache *sfmmu1_cache;
static struct kmem_cache *pa_hment_cache;

static kmutex_t         ism_mlist_lock; /* mutex for ism mapping list */
/*
 * private data for ism
 */
static struct kmem_cache *ism_blk_cache;
static struct kmem_cache *ism_ment_cache;
#define ISMID_STARTADDR NULL

/*
 * Region management data structures and function declarations.
 */

static void     sfmmu_leave_srd(sfmmu_t *);
static int      sfmmu_srdcache_constructor(void *, void *, int);
static void     sfmmu_srdcache_destructor(void *, void *);
static int      sfmmu_rgncache_constructor(void *, void *, int);
static void     sfmmu_rgncache_destructor(void *, void *);
static int      sfrgnmap_isnull(sf_region_map_t *);
static int      sfhmergnmap_isnull(sf_hmeregion_map_t *);
static int      sfmmu_scdcache_constructor(void *, void *, int);
static void     sfmmu_scdcache_destructor(void *, void *);
static void     sfmmu_rgn_cb_noop(caddr_t, caddr_t, caddr_t,
    size_t, void *, u_offset_t);

static uint_t srd_hashmask = SFMMU_MAX_SRD_BUCKETS - 1;
static sf_srd_bucket_t *srd_buckets;
static struct kmem_cache *srd_cache;
static uint_t srd_rgn_hashmask = SFMMU_MAX_REGION_BUCKETS - 1;
static struct kmem_cache *region_cache;
static struct kmem_cache *scd_cache;

#ifdef sun4v
int use_bigtsb_arena = 1;
#else
int use_bigtsb_arena = 0;
#endif

/* External /etc/system tunable, for turning on&off the shctx support */
int disable_shctx = 0;
/* Internal variable, set by MD if the HW supports shctx feature */
int shctx_on = 0;

#ifdef DEBUG
static void check_scd_sfmmu_list(sfmmu_t **, sfmmu_t *, int);
#endif
static void sfmmu_to_scd_list(sfmmu_t **, sfmmu_t *);
static void sfmmu_from_scd_list(sfmmu_t **, sfmmu_t *);

static sf_scd_t *sfmmu_alloc_scd(sf_srd_t *, sf_region_map_t *);
static void sfmmu_find_scd(sfmmu_t *);
static void sfmmu_join_scd(sf_scd_t *, sfmmu_t *);
static void sfmmu_finish_join_scd(sfmmu_t *);
static void sfmmu_leave_scd(sfmmu_t *, uchar_t);
static void sfmmu_destroy_scd(sf_srd_t *, sf_scd_t *, sf_region_map_t *);
static int sfmmu_alloc_scd_tsbs(sf_srd_t *, sf_scd_t *);
static void sfmmu_free_scd_tsbs(sfmmu_t *);
static void sfmmu_tsb_inv_ctx(sfmmu_t *);
static int find_ism_rid(sfmmu_t *, sfmmu_t *, caddr_t, uint_t *);
static void sfmmu_ism_hatflags(sfmmu_t *, int);
static int sfmmu_srd_lock_held(sf_srd_t *);
static void sfmmu_remove_scd(sf_scd_t **, sf_scd_t *);
static void sfmmu_add_scd(sf_scd_t **headp, sf_scd_t *);
static void sfmmu_link_scd_to_regions(sf_srd_t *, sf_scd_t *);
static void sfmmu_unlink_scd_from_regions(sf_srd_t *, sf_scd_t *);
static void sfmmu_link_to_hmeregion(sfmmu_t *, sf_region_t *);
static void sfmmu_unlink_from_hmeregion(sfmmu_t *, sf_region_t *);

/*
 * ``hat_lock'' is a hashed mutex lock for protecting sfmmu TSB lists,
 * HAT flags, synchronizing TLB/TSB coherency, and context management.
 * The lock is hashed on the sfmmup since the case where we need to lock
 * all processes is rare but does occur (e.g. we need to unload a shared
 * mapping from all processes using the mapping).  We have a lot of buckets,
 * and each slab of sfmmu_t's can use about a quarter of them, giving us
 * a fairly good distribution without wasting too much space and overhead
 * when we have to grab them all.
 */
#define SFMMU_NUM_LOCK  128             /* must be power of two */
hatlock_t       hat_lock[SFMMU_NUM_LOCK];

/*
 * Hash algorithm optimized for a small number of slabs.
 *  7 is (highbit((sizeof sfmmu_t)) - 1)
 * This hash algorithm is based upon the knowledge that sfmmu_t's come from a
 * kmem_cache, and thus they will be sequential within that cache.  In
 * addition, each new slab will have a different "color" up to cache_maxcolor
 * which will skew the hashing for each successive slab which is allocated.
 * If the size of sfmmu_t changed to a larger size, this algorithm may need
 * to be revisited.
 */
#define TSB_HASH_SHIFT_BITS (7)
#define PTR_HASH(x) ((uintptr_t)x >> TSB_HASH_SHIFT_BITS)

#ifdef DEBUG
int tsb_hash_debug = 0;
#define TSB_HASH(sfmmup)        \
        (tsb_hash_debug ? &hat_lock[0] : \
        &hat_lock[PTR_HASH(sfmmup) & (SFMMU_NUM_LOCK-1)])
#else   /* DEBUG */
#define TSB_HASH(sfmmup)        &hat_lock[PTR_HASH(sfmmup) & (SFMMU_NUM_LOCK-1)]
#endif  /* DEBUG */


/* sfmmu_replace_tsb() return codes. */
typedef enum tsb_replace_rc {
        TSB_SUCCESS,
        TSB_ALLOCFAIL,
        TSB_LOSTRACE,
        TSB_ALREADY_SWAPPED,
        TSB_CANTGROW
} tsb_replace_rc_t;

/*
 * Flags for TSB allocation routines.
 */
#define TSB_ALLOC       0x01
#define TSB_FORCEALLOC  0x02
#define TSB_GROW        0x04
#define TSB_SHRINK      0x08
#define TSB_SWAPIN      0x10

/*
 * Support for HAT callbacks.
 */
#define SFMMU_MAX_RELOC_CALLBACKS       10
int sfmmu_max_cb_id = SFMMU_MAX_RELOC_CALLBACKS;
static id_t sfmmu_cb_nextid = 0;
static id_t sfmmu_tsb_cb_id;
struct sfmmu_callback *sfmmu_cb_table;

kmutex_t        kpr_mutex;
kmutex_t        kpr_suspendlock;
kthread_t       *kreloc_thread;

/*
 * Enable VA->PA translation sanity checking on DEBUG kernels.
 * Disabled by default.  This is incompatible with some
 * drivers (error injector, RSM) so if it breaks you get
 * to keep both pieces.
 */
int hat_check_vtop = 0;

/*
 * Private sfmmu routines (prototypes)
 */
static struct hme_blk *sfmmu_shadow_hcreate(sfmmu_t *, caddr_t, int, uint_t);
static struct   hme_blk *sfmmu_hblk_alloc(sfmmu_t *, caddr_t,
                        struct hmehash_bucket *, uint_t, hmeblk_tag, uint_t,
                        uint_t);
static caddr_t  sfmmu_hblk_unload(struct hat *, struct hme_blk *, caddr_t,
                        caddr_t, demap_range_t *, uint_t);
static caddr_t  sfmmu_hblk_sync(struct hat *, struct hme_blk *, caddr_t,
                        caddr_t, int);
static void     sfmmu_hblk_free(struct hme_blk **);
static void     sfmmu_hblks_list_purge(struct hme_blk **, int);
static uint_t   sfmmu_get_free_hblk(struct hme_blk **, uint_t);
static uint_t   sfmmu_put_free_hblk(struct hme_blk *, uint_t);
static struct hme_blk *sfmmu_hblk_steal(int);
static int      sfmmu_steal_this_hblk(struct hmehash_bucket *,
                        struct hme_blk *, uint64_t, struct hme_blk *);
static caddr_t  sfmmu_hblk_unlock(struct hme_blk *, caddr_t, caddr_t);

static void     hat_do_memload_array(struct hat *, caddr_t, size_t,
                    struct page **, uint_t, uint_t, uint_t);
static void     hat_do_memload(struct hat *, caddr_t, struct page *,
                    uint_t, uint_t, uint_t);
static void     sfmmu_memload_batchsmall(struct hat *, caddr_t, page_t **,
                    uint_t, uint_t, pgcnt_t, uint_t);
void            sfmmu_tteload(struct hat *, tte_t *, caddr_t, page_t *,
                        uint_t);
static int      sfmmu_tteload_array(sfmmu_t *, tte_t *, caddr_t, page_t **,
                        uint_t, uint_t);
static struct hmehash_bucket *sfmmu_tteload_acquire_hashbucket(sfmmu_t *,
                                        caddr_t, int, uint_t);
static struct hme_blk *sfmmu_tteload_find_hmeblk(sfmmu_t *,
                        struct hmehash_bucket *, caddr_t, uint_t, uint_t,
                        uint_t);
static int      sfmmu_tteload_addentry(sfmmu_t *, struct hme_blk *, tte_t *,
                        caddr_t, page_t **, uint_t, uint_t);
static void     sfmmu_tteload_release_hashbucket(struct hmehash_bucket *);

static int      sfmmu_pagearray_setup(caddr_t, page_t **, tte_t *, int);
static pfn_t    sfmmu_uvatopfn(caddr_t, sfmmu_t *, tte_t *);
void            sfmmu_memtte(tte_t *, pfn_t, uint_t, int);
#ifdef VAC
static void     sfmmu_vac_conflict(struct hat *, caddr_t, page_t *);
static int      sfmmu_vacconflict_array(caddr_t, page_t *, int *);
int     tst_tnc(page_t *pp, pgcnt_t);
void    conv_tnc(page_t *pp, int);
#endif

static void     sfmmu_get_ctx(sfmmu_t *);
static void     sfmmu_free_sfmmu(sfmmu_t *);

static void     sfmmu_ttesync(struct hat *, caddr_t, tte_t *, page_t *);
static void     sfmmu_chgattr(struct hat *, caddr_t, size_t, uint_t, int);

cpuset_t        sfmmu_pageunload(page_t *, struct sf_hment *, int);
static void     hat_pagereload(struct page *, struct page *);
static cpuset_t sfmmu_pagesync(page_t *, struct sf_hment *, uint_t);
#ifdef VAC
void    sfmmu_page_cache_array(page_t *, int, int, pgcnt_t);
static void     sfmmu_page_cache(page_t *, int, int, int);
#endif

cpuset_t        sfmmu_rgntlb_demap(caddr_t, sf_region_t *,
    struct hme_blk *, int);
static void     sfmmu_tlbcache_demap(caddr_t, sfmmu_t *, struct hme_blk *,
                        pfn_t, int, int, int, int);
static void     sfmmu_ismtlbcache_demap(caddr_t, sfmmu_t *, struct hme_blk *,
                        pfn_t, int);
static void     sfmmu_tlb_demap(caddr_t, sfmmu_t *, struct hme_blk *, int, int);
static void     sfmmu_tlb_range_demap(demap_range_t *);
static void     sfmmu_invalidate_ctx(sfmmu_t *);
static void     sfmmu_sync_mmustate(sfmmu_t *);

static void     sfmmu_tsbinfo_setup_phys(struct tsb_info *, pfn_t);
static int      sfmmu_tsbinfo_alloc(struct tsb_info **, int, int, uint_t,
                        sfmmu_t *);
static void     sfmmu_tsb_free(struct tsb_info *);
static void     sfmmu_tsbinfo_free(struct tsb_info *);
static int      sfmmu_init_tsbinfo(struct tsb_info *, int, int, uint_t,
                        sfmmu_t *);
static void     sfmmu_tsb_chk_reloc(sfmmu_t *, hatlock_t *);
static void     sfmmu_tsb_swapin(sfmmu_t *, hatlock_t *);
static int      sfmmu_select_tsb_szc(pgcnt_t);
static void     sfmmu_mod_tsb(sfmmu_t *, caddr_t, tte_t *, int);
#define         sfmmu_load_tsb(sfmmup, vaddr, tte, szc) \
        sfmmu_mod_tsb(sfmmup, vaddr, tte, szc)
#define         sfmmu_unload_tsb(sfmmup, vaddr, szc)    \
        sfmmu_mod_tsb(sfmmup, vaddr, NULL, szc)
static void     sfmmu_copy_tsb(struct tsb_info *, struct tsb_info *);
static tsb_replace_rc_t sfmmu_replace_tsb(sfmmu_t *, struct tsb_info *, uint_t,
    hatlock_t *, uint_t);
static void     sfmmu_size_tsb(sfmmu_t *, int, uint64_t, uint64_t, int);

#ifdef VAC
void    sfmmu_cache_flush(pfn_t, int);
void    sfmmu_cache_flushcolor(int, pfn_t);
#endif
static caddr_t  sfmmu_hblk_chgattr(sfmmu_t *, struct hme_blk *, caddr_t,
                        caddr_t, demap_range_t *, uint_t, int);

static uint64_t sfmmu_vtop_attr(uint_t, int mode, tte_t *);
static uint_t   sfmmu_ptov_attr(tte_t *);
static caddr_t  sfmmu_hblk_chgprot(sfmmu_t *, struct hme_blk *, caddr_t,
                        caddr_t, demap_range_t *, uint_t);
static uint_t   sfmmu_vtop_prot(uint_t, uint_t *);
static int      sfmmu_idcache_constructor(void *, void *, int);
static void     sfmmu_idcache_destructor(void *, void *);
static int      sfmmu_hblkcache_constructor(void *, void *, int);
static void     sfmmu_hblkcache_destructor(void *, void *);
static void     sfmmu_hblkcache_reclaim(void *);
static void     sfmmu_shadow_hcleanup(sfmmu_t *, struct hme_blk *,
                        struct hmehash_bucket *);
static void     sfmmu_hblk_hash_rm(struct hmehash_bucket *, struct hme_blk *,
                        struct hme_blk *, struct hme_blk **, int);
static void     sfmmu_hblk_hash_add(struct hmehash_bucket *, struct hme_blk *,
                        uint64_t);
static struct hme_blk *sfmmu_check_pending_hblks(int);
static void     sfmmu_free_hblks(sfmmu_t *, caddr_t, caddr_t, int);
static void     sfmmu_cleanup_rhblk(sf_srd_t *, caddr_t, uint_t, int);
static void     sfmmu_unload_hmeregion_va(sf_srd_t *, uint_t, caddr_t, caddr_t,
                        int, caddr_t *);
static void     sfmmu_unload_hmeregion(sf_srd_t *, sf_region_t *);

static void     sfmmu_rm_large_mappings(page_t *, int);

static void     hat_lock_init(void);
static void     hat_kstat_init(void);
static int      sfmmu_kstat_percpu_update(kstat_t *ksp, int rw);
static void     sfmmu_set_scd_rttecnt(sf_srd_t *, sf_scd_t *);
static  int     sfmmu_is_rgnva(sf_srd_t *, caddr_t, ulong_t, ulong_t);
static void     sfmmu_check_page_sizes(sfmmu_t *, int);
int     fnd_mapping_sz(page_t *);
static void     iment_add(struct ism_ment *,  struct hat *);
static void     iment_sub(struct ism_ment *, struct hat *);
static pgcnt_t  ism_tsb_entries(sfmmu_t *, int szc);
extern void     sfmmu_setup_tsbinfo(sfmmu_t *);
extern void     sfmmu_clear_utsbinfo(void);

static void             sfmmu_ctx_wrap_around(mmu_ctx_t *, boolean_t);

extern int vpm_enable;

/* kpm globals */
#ifdef  DEBUG
/*
 * Enable trap level tsbmiss handling
 */
int     kpm_tsbmtl = 1;

/*
 * Flush the TLB on kpm mapout. Note: Xcalls are used (again) for the
 * required TLB shootdowns in this case, so handle w/ care. Off by default.
 */
int     kpm_tlb_flush;
#endif  /* DEBUG */

static void     *sfmmu_vmem_xalloc_aligned_wrapper(vmem_t *, size_t, int);

#ifdef DEBUG
static void     sfmmu_check_hblk_flist();
#endif

/*
 * Semi-private sfmmu data structures.  Some of them are initialize in
 * startup or in hat_init. Some of them are private but accessed by
 * assembly code or mach_sfmmu.c
 */
struct hmehash_bucket *uhme_hash;       /* user hmeblk hash table */
struct hmehash_bucket *khme_hash;       /* kernel hmeblk hash table */
uint64_t        uhme_hash_pa;           /* PA of uhme_hash */
uint64_t        khme_hash_pa;           /* PA of khme_hash */
int             uhmehash_num;           /* # of buckets in user hash table */
int             khmehash_num;           /* # of buckets in kernel hash table */

uint_t          max_mmu_ctxdoms = 0;    /* max context domains in the system */
mmu_ctx_t       **mmu_ctxs_tbl;         /* global array of context domains */
uint64_t        mmu_saved_gnum = 0;     /* to init incoming MMUs' gnums */

#define DEFAULT_NUM_CTXS_PER_MMU 8192
static uint_t   nctxs = DEFAULT_NUM_CTXS_PER_MMU;

int             cache;                  /* describes system cache */

caddr_t         ktsb_base;              /* kernel 8k-indexed tsb base address */
uint64_t        ktsb_pbase;             /* kernel 8k-indexed tsb phys address */
int             ktsb_szcode;            /* kernel 8k-indexed tsb size code */
int             ktsb_sz;                /* kernel 8k-indexed tsb size */

caddr_t         ktsb4m_base;            /* kernel 4m-indexed tsb base address */
uint64_t        ktsb4m_pbase;           /* kernel 4m-indexed tsb phys address */
int             ktsb4m_szcode;          /* kernel 4m-indexed tsb size code */
int             ktsb4m_sz;              /* kernel 4m-indexed tsb size */

uint64_t        kpm_tsbbase;            /* kernel seg_kpm 4M TSB base address */
int             kpm_tsbsz;              /* kernel seg_kpm 4M TSB size code */
uint64_t        kpmsm_tsbbase;          /* kernel seg_kpm 8K TSB base address */
int             kpmsm_tsbsz;            /* kernel seg_kpm 8K TSB size code */

#ifndef sun4v
int             utsb_dtlb_ttenum = -1;  /* index in TLB for utsb locked TTE */
int             utsb4m_dtlb_ttenum = -1; /* index in TLB for 4M TSB TTE */
int             dtlb_resv_ttenum;       /* index in TLB of first reserved TTE */
caddr_t         utsb_vabase;            /* reserved kernel virtual memory */
caddr_t         utsb4m_vabase;          /* for trap handler TSB accesses */
#endif /* sun4v */
uint64_t        tsb_alloc_bytes = 0;    /* bytes allocated to TSBs */
vmem_t          *kmem_tsb_default_arena[NLGRPS_MAX];    /* For dynamic TSBs */
vmem_t          *kmem_bigtsb_default_arena[NLGRPS_MAX]; /* dynamic 256M TSBs */

/*
 * Size to use for TSB slabs.  Future platforms that support page sizes
 * larger than 4M may wish to change these values, and provide their own
 * assembly macros for building and decoding the TSB base register contents.
 * Note disable_large_pages will override the value set here.
 */
static  uint_t tsb_slab_ttesz = TTE4M;
size_t  tsb_slab_size = MMU_PAGESIZE4M;
uint_t  tsb_slab_shift = MMU_PAGESHIFT4M;
/* PFN mask for TTE */
size_t  tsb_slab_mask = MMU_PAGEOFFSET4M >> MMU_PAGESHIFT;

/*
 * Size to use for TSB slabs.  These are used only when 256M tsb arenas
 * exist.
 */
static uint_t   bigtsb_slab_ttesz = TTE256M;
static size_t   bigtsb_slab_size = MMU_PAGESIZE256M;
static uint_t   bigtsb_slab_shift = MMU_PAGESHIFT256M;
/* 256M page alignment for 8K pfn */
static size_t   bigtsb_slab_mask = MMU_PAGEOFFSET256M >> MMU_PAGESHIFT;

/* largest TSB size to grow to, will be smaller on smaller memory systems */
static int      tsb_max_growsize = 0;

/*
 * Tunable parameters dealing with TSB policies.
 */

/*
 * This undocumented tunable forces all 8K TSBs to be allocated from
 * the kernel heap rather than from the kmem_tsb_default_arena arenas.
 */
#ifdef  DEBUG
int     tsb_forceheap = 0;
#endif  /* DEBUG */

/*
 * Decide whether to use per-lgroup arenas, or one global set of
 * TSB arenas.  The default is not to break up per-lgroup, since
 * most platforms don't recognize any tangible benefit from it.
 */
int     tsb_lgrp_affinity = 0;

/*
 * Used for growing the TSB based on the process RSS.
 * tsb_rss_factor is based on the smallest TSB, and is
 * shifted by the TSB size to determine if we need to grow.
 * The default will grow the TSB if the number of TTEs for
 * this page size exceeds 75% of the number of TSB entries,
 * which should _almost_ eliminate all conflict misses
 * (at the expense of using up lots and lots of memory).
 */
#define TSB_RSS_FACTOR          (TSB_ENTRIES(TSB_MIN_SZCODE) * 0.75)
#define SFMMU_RSS_TSBSIZE(tsbszc)       (tsb_rss_factor << tsbszc)
#define SELECT_TSB_SIZECODE(pgcnt) ( \
        (enable_tsb_rss_sizing)? sfmmu_select_tsb_szc(pgcnt) : \
        default_tsb_size)
#define TSB_OK_SHRINK() \
        (tsb_alloc_bytes > tsb_alloc_hiwater || freemem < desfree)
#define TSB_OK_GROW()   \
        (tsb_alloc_bytes < tsb_alloc_hiwater && freemem > desfree)

int     enable_tsb_rss_sizing = 1;
int     tsb_rss_factor  = (int)TSB_RSS_FACTOR;

/* which TSB size code to use for new address spaces or if rss sizing off */
int default_tsb_size = TSB_8K_SZCODE;

static uint64_t tsb_alloc_hiwater; /* limit TSB reserved memory */
uint64_t tsb_alloc_hiwater_factor; /* tsb_alloc_hiwater = physmem / this */
#define TSB_ALLOC_HIWATER_FACTOR_DEFAULT        32

#ifdef DEBUG
static int tsb_random_size = 0; /* set to 1 to test random tsb sizes on alloc */
static int tsb_grow_stress = 0; /* if set to 1, keep replacing TSB w/ random */
static int tsb_alloc_mtbf = 0;  /* fail allocation every n attempts */
static int tsb_alloc_fail_mtbf = 0;
static int tsb_alloc_count = 0;
#endif /* DEBUG */

/* if set to 1, will remap valid TTEs when growing TSB. */
int tsb_remap_ttes = 1;

/*
 * If we have more than this many mappings, allocate a second TSB.
 * This default is chosen because the I/D fully associative TLBs are
 * assumed to have at least 8 available entries. Platforms with a
 * larger fully-associative TLB could probably override the default.
 */

#ifdef sun4v
int tsb_sectsb_threshold = 0;
#else
int tsb_sectsb_threshold = 8;
#endif

/*
 * kstat data
 */
struct sfmmu_global_stat sfmmu_global_stat;
struct sfmmu_tsbsize_stat sfmmu_tsbsize_stat;

/*
 * Global data
 */
sfmmu_t         *ksfmmup;               /* kernel's hat id */

#ifdef DEBUG
static void     chk_tte(tte_t *, tte_t *, tte_t *, struct hme_blk *);
#endif

/* sfmmu locking operations */
static kmutex_t *sfmmu_mlspl_enter(struct page *, int);
static int      sfmmu_mlspl_held(struct page *, int);

kmutex_t *sfmmu_page_enter(page_t *);
void    sfmmu_page_exit(kmutex_t *);
int     sfmmu_page_spl_held(struct page *);

/* sfmmu internal locking operations - accessed directly */
static void     sfmmu_mlist_reloc_enter(page_t *, page_t *,
                                kmutex_t **, kmutex_t **);
static void     sfmmu_mlist_reloc_exit(kmutex_t *, kmutex_t *);
static hatlock_t *
                sfmmu_hat_enter(sfmmu_t *);
static hatlock_t *
                sfmmu_hat_tryenter(sfmmu_t *);
static void     sfmmu_hat_exit(hatlock_t *);
static void     sfmmu_hat_lock_all(void);
static void     sfmmu_hat_unlock_all(void);
static void     sfmmu_ismhat_enter(sfmmu_t *, int);
static void     sfmmu_ismhat_exit(sfmmu_t *, int);

kpm_hlk_t       *kpmp_table;
uint_t          kpmp_table_sz;  /* must be a power of 2 */
uchar_t         kpmp_shift;

kpm_shlk_t      *kpmp_stable;
uint_t          kpmp_stable_sz; /* must be a power of 2 */

/*
 * SPL_TABLE_SIZE is 2 * NCPU, but no smaller than 128.
 * SPL_SHIFT is log2(SPL_TABLE_SIZE).
 */
#if ((2*NCPU_P2) > 128)
#define SPL_SHIFT       ((unsigned)(NCPU_LOG2 + 1))
#else
#define SPL_SHIFT       7U
#endif
#define SPL_TABLE_SIZE  (1U << SPL_SHIFT)
#define SPL_MASK        (SPL_TABLE_SIZE - 1)

/*
 * We shift by PP_SHIFT to take care of the low-order 0 bits of a page_t
 * and by multiples of SPL_SHIFT to get as many varied bits as we can.
 */
#define SPL_INDEX(pp) \
        ((((uintptr_t)(pp) >> PP_SHIFT) ^ \
        ((uintptr_t)(pp) >> (PP_SHIFT + SPL_SHIFT)) ^ \
        ((uintptr_t)(pp) >> (PP_SHIFT + SPL_SHIFT * 2)) ^ \
        ((uintptr_t)(pp) >> (PP_SHIFT + SPL_SHIFT * 3))) & \
        SPL_MASK)

#define SPL_HASH(pp)    \
        (&sfmmu_page_lock[SPL_INDEX(pp)].pad_mutex)

static  pad_mutex_t     sfmmu_page_lock[SPL_TABLE_SIZE];

/* Array of mutexes protecting a page's mapping list and p_nrm field. */

#define MML_TABLE_SIZE  SPL_TABLE_SIZE
#define MLIST_HASH(pp)  (&mml_table[SPL_INDEX(pp)].pad_mutex)

static pad_mutex_t      mml_table[MML_TABLE_SIZE];

/*
 * hat_unload_callback() will group together callbacks in order
 * to avoid xt_sync() calls.  This is the maximum size of the group.
 */
#define MAX_CB_ADDR     32

tte_t   hw_tte;
static ulong_t sfmmu_dmr_maxbit = DMR_MAXBIT;

static char     *mmu_ctx_kstat_names[] = {
        "mmu_ctx_tsb_exceptions",
        "mmu_ctx_tsb_raise_exception",
        "mmu_ctx_wrap_around",
};

/*
 * Wrapper for vmem_xalloc since vmem_create only allows limited
 * parameters for vm_source_alloc functions.  This function allows us
 * to specify alignment consistent with the size of the object being
 * allocated.
 */
static void *
sfmmu_vmem_xalloc_aligned_wrapper(vmem_t *vmp, size_t size, int vmflag)
{
        return (vmem_xalloc(vmp, size, size, 0, 0, NULL, NULL, vmflag));
}

/* Common code for setting tsb_alloc_hiwater. */
#define SFMMU_SET_TSB_ALLOC_HIWATER(pages)      tsb_alloc_hiwater = \
                ptob(pages) / tsb_alloc_hiwater_factor

/*
 * Set tsb_max_growsize to allow at most all of physical memory to be mapped by
 * a single TSB.  physmem is the number of physical pages so we need physmem 8K
 * TTEs to represent all those physical pages.  We round this up by using
 * 1<<highbit().  To figure out which size code to use, remember that the size
 * code is just an amount to shift the smallest TSB size to get the size of
 * this TSB.  So we subtract that size, TSB_START_SIZE, from highbit() (or
 * highbit() - 1) to get the size code for the smallest TSB that can represent
 * all of physical memory, while erring on the side of too much.
 *
 * Restrict tsb_max_growsize to make sure that:
 *      1) TSBs can't grow larger than the TSB slab size
 *      2) TSBs can't grow larger than UTSB_MAX_SZCODE.
 */
#define SFMMU_SET_TSB_MAX_GROWSIZE(pages) {                             \
        int     _i, _szc, _slabszc, _tsbszc;                            \
                                                                        \
        _i = highbit(pages);                                            \
        if ((1 << (_i - 1)) == (pages))                                 \
                _i--;           /* 2^n case, round down */              \
        _szc = _i - TSB_START_SIZE;                                     \
        _slabszc = bigtsb_slab_shift - (TSB_START_SIZE + TSB_ENTRY_SHIFT); \
        _tsbszc = MIN(_szc, _slabszc);                                  \
        tsb_max_growsize = MIN(_tsbszc, UTSB_MAX_SZCODE);               \
}

/*
 * Given a pointer to an sfmmu and a TTE size code, return a pointer to the
 * tsb_info which handles that TTE size.
 */
#define SFMMU_GET_TSBINFO(tsbinfop, sfmmup, tte_szc) {                  \
        (tsbinfop) = (sfmmup)->sfmmu_tsb;                               \
        ASSERT(((tsbinfop)->tsb_flags & TSB_SHAREDCTX) ||               \
            sfmmu_hat_lock_held(sfmmup));                               \
        if ((tte_szc) >= TTE4M) {                                       \
                ASSERT((tsbinfop) != NULL);                             \
                (tsbinfop) = (tsbinfop)->tsb_next;                      \
        }                                                               \
}

/*
 * Macro to use to unload entries from the TSB.
 * It has knowledge of which page sizes get replicated in the TSB
 * and will call the appropriate unload routine for the appropriate size.
 */
#define SFMMU_UNLOAD_TSB(addr, sfmmup, hmeblkp, ismhat)         \
{                                                                       \
        int ttesz = get_hblk_ttesz(hmeblkp);                            \
        if (ttesz == TTE8K || ttesz == TTE4M) {                         \
                sfmmu_unload_tsb(sfmmup, addr, ttesz);                  \
        } else {                                                        \
                caddr_t sva = ismhat ? addr :                           \
                    (caddr_t)get_hblk_base(hmeblkp);                    \
                caddr_t eva = sva + get_hblk_span(hmeblkp);             \
                ASSERT(addr >= sva && addr < eva);                      \
                sfmmu_unload_tsb_range(sfmmup, sva, eva, ttesz);        \
        }                                                               \
}


/* Update tsb_alloc_hiwater after memory is configured. */
/*ARGSUSED*/
static void
sfmmu_update_post_add(void *arg, pgcnt_t delta_pages)
{
        /* Assumes physmem has already been updated. */
        SFMMU_SET_TSB_ALLOC_HIWATER(physmem);
        SFMMU_SET_TSB_MAX_GROWSIZE(physmem);
}

/*
 * Update tsb_alloc_hiwater before memory is deleted.  We'll do nothing here
 * and update tsb_alloc_hiwater and tsb_max_growsize after the memory is
 * deleted.
 */
/*ARGSUSED*/
static int
sfmmu_update_pre_del(void *arg, pgcnt_t delta_pages)
{
        return (0);
}

/* Update tsb_alloc_hiwater after memory fails to be unconfigured. */
/*ARGSUSED*/
static void
sfmmu_update_post_del(void *arg, pgcnt_t delta_pages, int cancelled)
{
        /*
         * Whether the delete was cancelled or not, just go ahead and update
         * tsb_alloc_hiwater and tsb_max_growsize.
         */
        SFMMU_SET_TSB_ALLOC_HIWATER(physmem);
        SFMMU_SET_TSB_MAX_GROWSIZE(physmem);
}

static kphysm_setup_vector_t sfmmu_update_vec = {
        KPHYSM_SETUP_VECTOR_VERSION,    /* version */
        sfmmu_update_post_add,          /* post_add */
        sfmmu_update_pre_del,           /* pre_del */
        sfmmu_update_post_del           /* post_del */
};


/*
 * HME_BLK HASH PRIMITIVES
 */

/*
 * Enter a hme on the mapping list for page pp.
 * When large pages are more prevalent in the system we might want to
 * keep the mapping list in ascending order by the hment size. For now,
 * small pages are more frequent, so don't slow it down.
 */
#define HME_ADD(hme, pp)                                        \
{                                                               \
        ASSERT(sfmmu_mlist_held(pp));                           \
                                                                \
        hme->hme_prev = NULL;                                   \
        hme->hme_next = pp->p_mapping;                          \
        hme->hme_page = pp;                                     \
        if (pp->p_mapping) {                                    \
                ((struct sf_hment *)(pp->p_mapping))->hme_prev = hme;\
                ASSERT(pp->p_share > 0);                        \
        } else  {                                               \
                /* EMPTY */                                     \
                ASSERT(pp->p_share == 0);                       \
        }                                                       \
        pp->p_mapping = hme;                                    \
        pp->p_share++;                                          \
}

/*
 * Enter a hme on the mapping list for page pp.
 * If we are unmapping a large translation, we need to make sure that the
 * change is reflect in the corresponding bit of the p_index field.
 */
#define HME_SUB(hme, pp)                                        \
{                                                               \
        ASSERT(sfmmu_mlist_held(pp));                           \
        ASSERT(hme->hme_page == pp || IS_PAHME(hme));           \
                                                                \
        if (pp->p_mapping == NULL) {                            \
                panic("hme_remove - no mappings");              \
        }                                                       \
                                                                \
        membar_stst();  /* ensure previous stores finish */     \
                                                                \
        ASSERT(pp->p_share > 0);                                \
        pp->p_share--;                                          \
                                                                \
        if (hme->hme_prev) {                                    \
                ASSERT(pp->p_mapping != hme);                   \
                ASSERT(hme->hme_prev->hme_page == pp ||         \
                        IS_PAHME(hme->hme_prev));               \
                hme->hme_prev->hme_next = hme->hme_next;        \
        } else {                                                \
                ASSERT(pp->p_mapping == hme);                   \
                pp->p_mapping = hme->hme_next;                  \
                ASSERT((pp->p_mapping == NULL) ?                \
                        (pp->p_share == 0) : 1);                \
        }                                                       \
                                                                \
        if (hme->hme_next) {                                    \
                ASSERT(hme->hme_next->hme_page == pp ||         \
                        IS_PAHME(hme->hme_next));               \
                hme->hme_next->hme_prev = hme->hme_prev;        \
        }                                                       \
                                                                \
        /* zero out the entry */                                \
        hme->hme_next = NULL;                                   \
        hme->hme_prev = NULL;                                   \
        hme->hme_page = NULL;                                   \
                                                                \
        if (hme_size(hme) > TTE8K) {                            \
                /* remove mappings for remainder of large pg */ \
                sfmmu_rm_large_mappings(pp, hme_size(hme));     \
        }                                                       \
}

/*
 * This function returns the hment given the hme_blk and a vaddr.
 * It assumes addr has already been checked to belong to hme_blk's
 * range.
 */
#define HBLKTOHME(hment, hmeblkp, addr)                                 \
{                                                                       \
        int index;                                                      \
        HBLKTOHME_IDX(hment, hmeblkp, addr, index)                      \
}

/*
 * Version of HBLKTOHME that also returns the index in hmeblkp
 * of the hment.
 */
#define HBLKTOHME_IDX(hment, hmeblkp, addr, idx)                        \
{                                                                       \
        ASSERT(in_hblk_range((hmeblkp), (addr)));                       \
                                                                        \
        if (get_hblk_ttesz(hmeblkp) == TTE8K) {                         \
                idx = (((uintptr_t)(addr) >> MMU_PAGESHIFT) & (NHMENTS-1)); \
        } else                                                          \
                idx = 0;                                                \
                                                                        \
        (hment) = &(hmeblkp)->hblk_hme[idx];                            \
}

/*
 * Disable any page sizes not supported by the CPU
 */
void
hat_init_pagesizes()
{
        int             i;

        mmu_exported_page_sizes = 0;
        for (i = TTE8K; i < max_mmu_page_sizes; i++) {

                szc_2_userszc[i] = (uint_t)-1;
                userszc_2_szc[i] = (uint_t)-1;

                if ((mmu_exported_pagesize_mask & (1 << i)) == 0) {
                        disable_large_pages |= (1 << i);
                } else {
                        szc_2_userszc[i] = mmu_exported_page_sizes;
                        userszc_2_szc[mmu_exported_page_sizes] = i;
                        mmu_exported_page_sizes++;
                }
        }

        disable_ism_large_pages |= disable_large_pages;
        disable_auto_data_large_pages = disable_large_pages;
        disable_auto_text_large_pages = disable_large_pages;

        /*
         * Initialize mmu-specific large page sizes.
         */
        if (&mmu_large_pages_disabled) {
                disable_large_pages |= mmu_large_pages_disabled(HAT_LOAD);
                disable_ism_large_pages |=
                    mmu_large_pages_disabled(HAT_LOAD_SHARE);
                disable_auto_data_large_pages |=
                    mmu_large_pages_disabled(HAT_AUTO_DATA);
                disable_auto_text_large_pages |=
                    mmu_large_pages_disabled(HAT_AUTO_TEXT);
        }
}

/*
 * Initialize the hardware address translation structures.
 */
void
hat_init(void)
{
        int             i;
        uint_t          sz;
        size_t          size;

        hat_lock_init();
        hat_kstat_init();

        /*
         * Hardware-only bits in a TTE
         */
        MAKE_TTE_MASK(&hw_tte);

        hat_init_pagesizes();

        /* Initialize the hash locks */
        for (i = 0; i < khmehash_num; i++) {
                mutex_init(&khme_hash[i].hmehash_mutex, NULL,
                    MUTEX_DEFAULT, NULL);
                khme_hash[i].hmeh_nextpa = HMEBLK_ENDPA;
        }
        for (i = 0; i < uhmehash_num; i++) {
                mutex_init(&uhme_hash[i].hmehash_mutex, NULL,
                    MUTEX_DEFAULT, NULL);
                uhme_hash[i].hmeh_nextpa = HMEBLK_ENDPA;
        }
        khmehash_num--;         /* make sure counter starts from 0 */
        uhmehash_num--;         /* make sure counter starts from 0 */

        /*
         * Allocate context domain structures.
         *
         * A platform may choose to modify max_mmu_ctxdoms in
         * set_platform_defaults(). If a platform does not define
         * a set_platform_defaults() or does not choose to modify
         * max_mmu_ctxdoms, it gets one MMU context domain for every CPU.
         *
         * For all platforms that have CPUs sharing MMUs, this
         * value must be defined.
         */
        if (max_mmu_ctxdoms == 0)
                max_mmu_ctxdoms = max_ncpus;

        size = max_mmu_ctxdoms * sizeof (mmu_ctx_t *);
        mmu_ctxs_tbl = kmem_zalloc(size, KM_SLEEP);

        /* mmu_ctx_t is 64 bytes aligned */
        mmuctxdom_cache = kmem_cache_create("mmuctxdom_cache",
            sizeof (mmu_ctx_t), 64, NULL, NULL, NULL, NULL, NULL, 0);
        /*
         * MMU context domain initialization for the Boot CPU.
         * This needs the context domains array allocated above.
         */
        mutex_enter(&cpu_lock);
        sfmmu_cpu_init(CPU);
        mutex_exit(&cpu_lock);

        /*
         * Intialize ism mapping list lock.
         */

        mutex_init(&ism_mlist_lock, NULL, MUTEX_DEFAULT, NULL);

        /*
         * Each sfmmu structure carries an array of MMU context info
         * structures, one per context domain. The size of this array depends
         * on the maximum number of context domains. So, the size of the
         * sfmmu structure varies per platform.
         *
         * sfmmu is allocated from static arena, because trap
         * handler at TL > 0 is not allowed to touch kernel relocatable
         * memory. sfmmu's alignment is changed to 64 bytes from
         * default 8 bytes, as the lower 6 bits will be used to pass
         * pgcnt to vtag_flush_pgcnt_tl1.
         */
        size = sizeof (sfmmu_t) + sizeof (sfmmu_ctx_t) * (max_mmu_ctxdoms - 1);

        sfmmuid_cache = kmem_cache_create("sfmmuid_cache", size,
            64, sfmmu_idcache_constructor, sfmmu_idcache_destructor,
            NULL, NULL, static_arena, 0);

        sfmmu_tsbinfo_cache = kmem_cache_create("sfmmu_tsbinfo_cache",
            sizeof (struct tsb_info), 0, NULL, NULL, NULL, NULL, NULL, 0);

        /*
         * Since we only use the tsb8k cache to "borrow" pages for TSBs
         * from the heap when low on memory or when TSB_FORCEALLOC is
         * specified, don't use magazines to cache them--we want to return
         * them to the system as quickly as possible.
         */
        sfmmu_tsb8k_cache = kmem_cache_create("sfmmu_tsb8k_cache",
            MMU_PAGESIZE, MMU_PAGESIZE, NULL, NULL, NULL, NULL,
            static_arena, KMC_NOMAGAZINE);

        /*
         * Set tsb_alloc_hiwater to 1/tsb_alloc_hiwater_factor of physical
         * memory, which corresponds to the old static reserve for TSBs.
         * tsb_alloc_hiwater_factor defaults to 32.  This caps the amount of
         * memory we'll allocate for TSB slabs; beyond this point TSB
         * allocations will be taken from the kernel heap (via
         * sfmmu_tsb8k_cache) and will be throttled as would any other kmem
         * consumer.
         */
        if (tsb_alloc_hiwater_factor == 0) {
                tsb_alloc_hiwater_factor = TSB_ALLOC_HIWATER_FACTOR_DEFAULT;
        }
        SFMMU_SET_TSB_ALLOC_HIWATER(physmem);

        for (sz = tsb_slab_ttesz; sz > 0; sz--) {
                if (!(disable_large_pages & (1 << sz)))
                        break;
        }

        if (sz < tsb_slab_ttesz) {
                tsb_slab_ttesz = sz;
                tsb_slab_shift = MMU_PAGESHIFT + (sz << 1) + sz;
                tsb_slab_size = 1 << tsb_slab_shift;
                tsb_slab_mask = (1 << (tsb_slab_shift - MMU_PAGESHIFT)) - 1;
                use_bigtsb_arena = 0;
        } else if (use_bigtsb_arena &&
            (disable_large_pages & (1 << bigtsb_slab_ttesz))) {
                use_bigtsb_arena = 0;
        }

        if (!use_bigtsb_arena) {
                bigtsb_slab_shift = tsb_slab_shift;
        }
        SFMMU_SET_TSB_MAX_GROWSIZE(physmem);

        /*
         * On smaller memory systems, allocate TSB memory in smaller chunks
         * than the default 4M slab size. We also honor disable_large_pages
         * here.
         *
         * The trap handlers need to be patched with the final slab shift,
         * since they need to be able to construct the TSB pointer at runtime.
         */
        if ((tsb_max_growsize <= TSB_512K_SZCODE) &&
            !(disable_large_pages & (1 << TTE512K))) {
                tsb_slab_ttesz = TTE512K;
                tsb_slab_shift = MMU_PAGESHIFT512K;
                tsb_slab_size = MMU_PAGESIZE512K;
                tsb_slab_mask = MMU_PAGEOFFSET512K >> MMU_PAGESHIFT;
                use_bigtsb_arena = 0;
        }

        if (!use_bigtsb_arena) {
                bigtsb_slab_ttesz = tsb_slab_ttesz;
                bigtsb_slab_shift = tsb_slab_shift;
                bigtsb_slab_size = tsb_slab_size;
                bigtsb_slab_mask = tsb_slab_mask;
        }


        /*
         * Set up memory callback to update tsb_alloc_hiwater and
         * tsb_max_growsize.
         */
        i = kphysm_setup_func_register(&sfmmu_update_vec, (void *) 0);
        ASSERT(i == 0);

        /*
         * kmem_tsb_arena is the source from which large TSB slabs are
         * drawn.  The quantum of this arena corresponds to the largest
         * TSB size we can dynamically allocate for user processes.
         * Currently it must also be a supported page size since we
         * use exactly one translation entry to map each slab page.
         *
         * The per-lgroup kmem_tsb_default_arena arenas are the arenas from
         * which most TSBs are allocated.  Since most TSB allocations are
         * typically 8K we have a kmem cache we stack on top of each
         * kmem_tsb_default_arena to speed up those allocations.
         *
         * Note the two-level scheme of arenas is required only
         * because vmem_create doesn't allow us to specify alignment
         * requirements.  If this ever changes the code could be
         * simplified to use only one level of arenas.
         *
         * If 256M page support exists on sun4v, 256MB kmem_bigtsb_arena
         * will be provided in addition to the 4M kmem_tsb_arena.
         */
        if (use_bigtsb_arena) {
                kmem_bigtsb_arena = vmem_create("kmem_bigtsb", NULL, 0,
                    bigtsb_slab_size, sfmmu_vmem_xalloc_aligned_wrapper,
                    vmem_xfree, heap_arena, 0, VM_SLEEP);
        }

        kmem_tsb_arena = vmem_create("kmem_tsb", NULL, 0, tsb_slab_size,
            sfmmu_vmem_xalloc_aligned_wrapper,
            vmem_xfree, heap_arena, 0, VM_SLEEP);

        if (tsb_lgrp_affinity) {
                char s[50];
                for (i = 0; i < NLGRPS_MAX; i++) {
                        if (use_bigtsb_arena) {
                                (void) sprintf(s, "kmem_bigtsb_lgrp%d", i);
                                kmem_bigtsb_default_arena[i] = vmem_create(s,
                                    NULL, 0, 2 * tsb_slab_size,
                                    sfmmu_tsb_segkmem_alloc,
                                    sfmmu_tsb_segkmem_free, kmem_bigtsb_arena,
                                    0, VM_SLEEP | VM_BESTFIT);
                        }

                        (void) sprintf(s, "kmem_tsb_lgrp%d", i);
                        kmem_tsb_default_arena[i] = vmem_create(s,
                            NULL, 0, PAGESIZE, sfmmu_tsb_segkmem_alloc,
                            sfmmu_tsb_segkmem_free, kmem_tsb_arena, 0,
                            VM_SLEEP | VM_BESTFIT);

                        (void) sprintf(s, "sfmmu_tsb_lgrp%d_cache", i);
                        sfmmu_tsb_cache[i] = kmem_cache_create(s,
                            PAGESIZE, PAGESIZE, NULL, NULL, NULL, NULL,
                            kmem_tsb_default_arena[i], 0);
                }
        } else {
                if (use_bigtsb_arena) {
                        kmem_bigtsb_default_arena[0] =
                            vmem_create("kmem_bigtsb_default", NULL, 0,
                            2 * tsb_slab_size, sfmmu_tsb_segkmem_alloc,
                            sfmmu_tsb_segkmem_free, kmem_bigtsb_arena, 0,
                            VM_SLEEP | VM_BESTFIT);
                }

                kmem_tsb_default_arena[0] = vmem_create("kmem_tsb_default",
                    NULL, 0, PAGESIZE, sfmmu_tsb_segkmem_alloc,
                    sfmmu_tsb_segkmem_free, kmem_tsb_arena, 0,
                    VM_SLEEP | VM_BESTFIT);
                sfmmu_tsb_cache[0] = kmem_cache_create("sfmmu_tsb_cache",
                    PAGESIZE, PAGESIZE, NULL, NULL, NULL, NULL,
                    kmem_tsb_default_arena[0], 0);
        }

        sfmmu8_cache = kmem_cache_create("sfmmu8_cache", HME8BLK_SZ,
            HMEBLK_ALIGN, sfmmu_hblkcache_constructor,
            sfmmu_hblkcache_destructor,
            sfmmu_hblkcache_reclaim, (void *)HME8BLK_SZ,
            hat_memload_arena, KMC_NOHASH);

        hat_memload1_arena = vmem_create("hat_memload1", NULL, 0, PAGESIZE,
            segkmem_alloc_permanent, segkmem_free, heap_arena, 0,
            VMC_DUMPSAFE | VM_SLEEP);

        sfmmu1_cache = kmem_cache_create("sfmmu1_cache", HME1BLK_SZ,
            HMEBLK_ALIGN, sfmmu_hblkcache_constructor,
            sfmmu_hblkcache_destructor,
            NULL, (void *)HME1BLK_SZ,
            hat_memload1_arena, KMC_NOHASH);

        pa_hment_cache = kmem_cache_create("pa_hment_cache", PAHME_SZ,
            0, NULL, NULL, NULL, NULL, static_arena, KMC_NOHASH);

        ism_blk_cache = kmem_cache_create("ism_blk_cache",
            sizeof (ism_blk_t), ecache_alignsize, NULL, NULL,
            NULL, NULL, static_arena, KMC_NOHASH);

        ism_ment_cache = kmem_cache_create("ism_ment_cache",
            sizeof (ism_ment_t), 0, NULL, NULL,
            NULL, NULL, NULL, 0);

        /*
         * We grab the first hat for the kernel,
         */
        AS_LOCK_ENTER(&kas, RW_WRITER);
        kas.a_hat = hat_alloc(&kas);
        AS_LOCK_EXIT(&kas);

        /*
         * Initialize hblk_reserve.
         */
        ((struct hme_blk *)hblk_reserve)->hblk_nextpa =
            va_to_pa((caddr_t)hblk_reserve);

#ifndef UTSB_PHYS
        /*
         * Reserve some kernel virtual address space for the locked TTEs
         * that allow us to probe the TSB from TL>0.
         */
        utsb_vabase = vmem_xalloc(heap_arena, tsb_slab_size, tsb_slab_size,
            0, 0, NULL, NULL, VM_SLEEP);
        utsb4m_vabase = vmem_xalloc(heap_arena, tsb_slab_size, tsb_slab_size,
            0, 0, NULL, NULL, VM_SLEEP);
#endif

#ifdef VAC
        /*
         * The big page VAC handling code assumes VAC
         * will not be bigger than the smallest big
         * page- which is 64K.
         */
        if (TTEPAGES(TTE64K) < CACHE_NUM_COLOR) {
                cmn_err(CE_PANIC, "VAC too big!");
        }
#endif

        uhme_hash_pa = va_to_pa(uhme_hash);
        khme_hash_pa = va_to_pa(khme_hash);

        /*
         * Initialize relocation locks. kpr_suspendlock is held
         * at PIL_MAX to prevent interrupts from pinning the holder
         * of a suspended TTE which may access it leading to a
         * deadlock condition.
         */
        mutex_init(&kpr_mutex, NULL, MUTEX_DEFAULT, NULL);
        mutex_init(&kpr_suspendlock, NULL, MUTEX_SPIN, (void *)PIL_MAX);

        /*
         * If Shared context support is disabled via /etc/system
         * set shctx_on to 0 here if it was set to 1 earlier in boot
         * sequence by cpu module initialization code.
         */
        if (shctx_on && disable_shctx) {
                shctx_on = 0;
        }

        if (shctx_on) {
                srd_buckets = kmem_zalloc(SFMMU_MAX_SRD_BUCKETS *
                    sizeof (srd_buckets[0]), KM_SLEEP);
                for (i = 0; i < SFMMU_MAX_SRD_BUCKETS; i++) {
                        mutex_init(&srd_buckets[i].srdb_lock, NULL,
                            MUTEX_DEFAULT, NULL);
                }

                srd_cache = kmem_cache_create("srd_cache", sizeof (sf_srd_t),
                    0, sfmmu_srdcache_constructor, sfmmu_srdcache_destructor,
                    NULL, NULL, NULL, 0);
                region_cache = kmem_cache_create("region_cache",
                    sizeof (sf_region_t), 0, sfmmu_rgncache_constructor,
                    sfmmu_rgncache_destructor, NULL, NULL, NULL, 0);
                scd_cache = kmem_cache_create("scd_cache", sizeof (sf_scd_t),
                    0, sfmmu_scdcache_constructor,  sfmmu_scdcache_destructor,
                    NULL, NULL, NULL, 0);
        }

        /*
         * Pre-allocate hrm_hashtab before enabling the collection of
         * refmod statistics.  Allocating on the fly would mean us
         * running the risk of suffering recursive mutex enters or
         * deadlocks.
         */
        hrm_hashtab = kmem_zalloc(HRM_HASHSIZE * sizeof (struct hrmstat *),
            KM_SLEEP);

        /* Allocate per-cpu pending freelist of hmeblks */
        cpu_hme_pend = kmem_zalloc((NCPU * sizeof (cpu_hme_pend_t)) + 64,
            KM_SLEEP);
        cpu_hme_pend = (cpu_hme_pend_t *)P2ROUNDUP(
            (uintptr_t)cpu_hme_pend, 64);

        for (i = 0; i < NCPU; i++) {
                mutex_init(&cpu_hme_pend[i].chp_mutex, NULL, MUTEX_DEFAULT,
                    NULL);
        }

        if (cpu_hme_pend_thresh == 0) {
                cpu_hme_pend_thresh = CPU_HME_PEND_THRESH;
        }
}

/*
 * Initialize locking for the hat layer, called early during boot.
 */
static void
hat_lock_init()
{
        int i;

        /*
         * initialize the array of mutexes protecting a page's mapping
         * list and p_nrm field.
         */
        for (i = 0; i < MML_TABLE_SIZE; i++)
                mutex_init(&mml_table[i].pad_mutex, NULL, MUTEX_DEFAULT, NULL);

        if (kpm_enable) {
                for (i = 0; i < kpmp_table_sz; i++) {
                        mutex_init(&kpmp_table[i].khl_mutex, NULL,
                            MUTEX_DEFAULT, NULL);
                }
        }

        /*
         * Initialize array of mutex locks that protects sfmmu fields and
         * TSB lists.
         */
        for (i = 0; i < SFMMU_NUM_LOCK; i++)
                mutex_init(HATLOCK_MUTEXP(&hat_lock[i]), NULL, MUTEX_DEFAULT,
                    NULL);
}

#define SFMMU_KERNEL_MAXVA \
        (kmem64_base ? (uintptr_t)kmem64_end : (SYSLIMIT))

/*
 * Allocate a hat structure.
 * Called when an address space first uses a hat.
 */
struct hat *
hat_alloc(struct as *as)
{
        sfmmu_t *sfmmup;
        int i;
        uint64_t cnum;
        extern uint_t get_color_start(struct as *);

        ASSERT(AS_WRITE_HELD(as));
        sfmmup = kmem_cache_alloc(sfmmuid_cache, KM_SLEEP);
        sfmmup->sfmmu_as = as;
        sfmmup->sfmmu_flags = 0;
        sfmmup->sfmmu_tteflags = 0;
        sfmmup->sfmmu_rtteflags = 0;
        LOCK_INIT_CLEAR(&sfmmup->sfmmu_ctx_lock);

        if (as == &kas) {
                ksfmmup = sfmmup;
                sfmmup->sfmmu_cext = 0;
                cnum = KCONTEXT;

                sfmmup->sfmmu_clrstart = 0;
                sfmmup->sfmmu_tsb = NULL;
                /*
                 * hat_kern_setup() will call sfmmu_init_ktsbinfo()
                 * to setup tsb_info for ksfmmup.
                 */
        } else {

                /*
                 * Just set to invalid ctx. When it faults, it will
                 * get a valid ctx. This would avoid the situation
                 * where we get a ctx, but it gets stolen and then
                 * we fault when we try to run and so have to get
                 * another ctx.
                 */
                sfmmup->sfmmu_cext = 0;
                cnum = INVALID_CONTEXT;

                /* initialize original physical page coloring bin */
                sfmmup->sfmmu_clrstart = get_color_start(as);
#ifdef DEBUG
                if (tsb_random_size) {
                        uint32_t randval = (uint32_t)gettick() >> 4;
                        int size = randval % (tsb_max_growsize + 1);

                        /* chose a random tsb size for stress testing */
                        (void) sfmmu_tsbinfo_alloc(&sfmmup->sfmmu_tsb, size,
                            TSB8K|TSB64K|TSB512K, 0, sfmmup);
                } else
#endif /* DEBUG */
                        (void) sfmmu_tsbinfo_alloc(&sfmmup->sfmmu_tsb,
                            default_tsb_size,
                            TSB8K|TSB64K|TSB512K, 0, sfmmup);
                sfmmup->sfmmu_flags = HAT_SWAPPED | HAT_ALLCTX_INVALID;
                ASSERT(sfmmup->sfmmu_tsb != NULL);
        }

        ASSERT(max_mmu_ctxdoms > 0);
        for (i = 0; i < max_mmu_ctxdoms; i++) {
                sfmmup->sfmmu_ctxs[i].cnum = cnum;
                sfmmup->sfmmu_ctxs[i].gnum = 0;
        }

        for (i = 0; i < max_mmu_page_sizes; i++) {
                sfmmup->sfmmu_ttecnt[i] = 0;
                sfmmup->sfmmu_scdrttecnt[i] = 0;
                sfmmup->sfmmu_ismttecnt[i] = 0;
                sfmmup->sfmmu_scdismttecnt[i] = 0;
                sfmmup->sfmmu_pgsz[i] = TTE8K;
        }
        sfmmup->sfmmu_tsb0_4minflcnt = 0;
        sfmmup->sfmmu_iblk = NULL;
        sfmmup->sfmmu_ismhat = 0;
        sfmmup->sfmmu_scdhat = 0;
        sfmmup->sfmmu_ismblkpa = (uint64_t)-1;
        if (sfmmup == ksfmmup) {
                CPUSET_ALL(sfmmup->sfmmu_cpusran);
        } else {
                CPUSET_ZERO(sfmmup->sfmmu_cpusran);
        }
        sfmmup->sfmmu_free = 0;
        sfmmup->sfmmu_rmstat = 0;
        sfmmup->sfmmu_clrbin = sfmmup->sfmmu_clrstart;
        cv_init(&sfmmup->sfmmu_tsb_cv, NULL, CV_DEFAULT, NULL);
        sfmmup->sfmmu_srdp = NULL;
        SF_RGNMAP_ZERO(sfmmup->sfmmu_region_map);
        bzero(sfmmup->sfmmu_hmeregion_links, SFMMU_L1_HMERLINKS_SIZE);
        sfmmup->sfmmu_scdp = NULL;
        sfmmup->sfmmu_scd_link.next = NULL;
        sfmmup->sfmmu_scd_link.prev = NULL;
        return (sfmmup);
}

/*
 * Create per-MMU context domain kstats for a given MMU ctx.
 */
static void
sfmmu_mmu_kstat_create(mmu_ctx_t *mmu_ctxp)
{
        mmu_ctx_stat_t  stat;
        kstat_t         *mmu_kstat;

        ASSERT(MUTEX_HELD(&cpu_lock));
        ASSERT(mmu_ctxp->mmu_kstat == NULL);

        mmu_kstat = kstat_create("unix", mmu_ctxp->mmu_idx, "mmu_ctx",
            "hat", KSTAT_TYPE_NAMED, MMU_CTX_NUM_STATS, KSTAT_FLAG_VIRTUAL);

        if (mmu_kstat == NULL) {
                cmn_err(CE_WARN, "kstat_create for MMU %d failed",
                    mmu_ctxp->mmu_idx);
        } else {
                mmu_kstat->ks_data = mmu_ctxp->mmu_kstat_data;
                for (stat = 0; stat < MMU_CTX_NUM_STATS; stat++)
                        kstat_named_init(&mmu_ctxp->mmu_kstat_data[stat],
                            mmu_ctx_kstat_names[stat], KSTAT_DATA_INT64);
                mmu_ctxp->mmu_kstat = mmu_kstat;
                kstat_install(mmu_kstat);
        }
}

/*
 * plat_cpuid_to_mmu_ctx_info() is a platform interface that returns MMU
 * context domain information for a given CPU. If a platform does not
 * specify that interface, then the function below is used instead to return
 * default information. The defaults are as follows:
 *
 *      - The number of MMU context IDs supported on any CPU in the
 *        system is 8K.
 *      - There is one MMU context domain per CPU.
 */
/*ARGSUSED*/
static void
sfmmu_cpuid_to_mmu_ctx_info(processorid_t cpuid, mmu_ctx_info_t *infop)
{
        infop->mmu_nctxs = nctxs;
        infop->mmu_idx = cpu[cpuid]->cpu_seqid;
}

/*
 * Called during CPU initialization to set the MMU context-related information
 * for a CPU.
 *
 * cpu_lock serializes accesses to mmu_ctxs and mmu_saved_gnum.
 */
void
sfmmu_cpu_init(cpu_t *cp)
{
        mmu_ctx_info_t  info;
        mmu_ctx_t       *mmu_ctxp;

        ASSERT(MUTEX_HELD(&cpu_lock));

        if (&plat_cpuid_to_mmu_ctx_info == NULL)
                sfmmu_cpuid_to_mmu_ctx_info(cp->cpu_id, &info);
        else
                plat_cpuid_to_mmu_ctx_info(cp->cpu_id, &info);

        ASSERT(info.mmu_idx < max_mmu_ctxdoms);

        if ((mmu_ctxp = mmu_ctxs_tbl[info.mmu_idx]) == NULL) {
                /* Each mmu_ctx is cacheline aligned. */
                mmu_ctxp = kmem_cache_alloc(mmuctxdom_cache, KM_SLEEP);
                bzero(mmu_ctxp, sizeof (mmu_ctx_t));

                mutex_init(&mmu_ctxp->mmu_lock, NULL, MUTEX_SPIN,
                    (void *)ipltospl(DISP_LEVEL));
                mmu_ctxp->mmu_idx = info.mmu_idx;
                mmu_ctxp->mmu_nctxs = info.mmu_nctxs;
                /*
                 * Globally for lifetime of a system,
                 * gnum must always increase.
                 * mmu_saved_gnum is protected by the cpu_lock.
                 */
                mmu_ctxp->mmu_gnum = mmu_saved_gnum + 1;
                mmu_ctxp->mmu_cnum = NUM_LOCKED_CTXS;

                sfmmu_mmu_kstat_create(mmu_ctxp);

                mmu_ctxs_tbl[info.mmu_idx] = mmu_ctxp;
        } else {
                ASSERT(mmu_ctxp->mmu_idx == info.mmu_idx);
                ASSERT(mmu_ctxp->mmu_nctxs <= info.mmu_nctxs);
        }

        /*
         * The mmu_lock is acquired here to prevent races with
         * the wrap-around code.
         */
        mutex_enter(&mmu_ctxp->mmu_lock);


        mmu_ctxp->mmu_ncpus++;
        CPUSET_ADD(mmu_ctxp->mmu_cpuset, cp->cpu_id);
        CPU_MMU_IDX(cp) = info.mmu_idx;
        CPU_MMU_CTXP(cp) = mmu_ctxp;

        mutex_exit(&mmu_ctxp->mmu_lock);
}

static void
sfmmu_ctxdom_free(mmu_ctx_t *mmu_ctxp)
{
        ASSERT(MUTEX_HELD(&cpu_lock));
        ASSERT(!MUTEX_HELD(&mmu_ctxp->mmu_lock));

        mutex_destroy(&mmu_ctxp->mmu_lock);

        if (mmu_ctxp->mmu_kstat)
                kstat_delete(mmu_ctxp->mmu_kstat);

        /* mmu_saved_gnum is protected by the cpu_lock. */
        if (mmu_saved_gnum < mmu_ctxp->mmu_gnum)
                mmu_saved_gnum = mmu_ctxp->mmu_gnum;

        kmem_cache_free(mmuctxdom_cache, mmu_ctxp);
}

/*
 * Called to perform MMU context-related cleanup for a CPU.
 */
void
sfmmu_cpu_cleanup(cpu_t *cp)
{
        mmu_ctx_t       *mmu_ctxp;

        ASSERT(MUTEX_HELD(&cpu_lock));

        mmu_ctxp = CPU_MMU_CTXP(cp);
        ASSERT(mmu_ctxp != NULL);

        /*
         * The mmu_lock is acquired here to prevent races with
         * the wrap-around code.
         */
        mutex_enter(&mmu_ctxp->mmu_lock);

        CPU_MMU_CTXP(cp) = NULL;

        CPUSET_DEL(mmu_ctxp->mmu_cpuset, cp->cpu_id);
        if (--mmu_ctxp->mmu_ncpus == 0) {
                mmu_ctxs_tbl[mmu_ctxp->mmu_idx] = NULL;
                mutex_exit(&mmu_ctxp->mmu_lock);
                sfmmu_ctxdom_free(mmu_ctxp);
                return;
        }

        mutex_exit(&mmu_ctxp->mmu_lock);
}

uint_t
sfmmu_ctxdom_nctxs(int idx)
{
        return (mmu_ctxs_tbl[idx]->mmu_nctxs);
}

#ifdef sun4v
/*
 * sfmmu_ctxdoms_* is an interface provided to help keep context domains
 * consistant after suspend/resume on system that can resume on a different
 * hardware than it was suspended.
 *
 * sfmmu_ctxdom_lock(void) locks all context domains and prevents new contexts
 * from being allocated.  It acquires all hat_locks, which blocks most access to
 * context data, except for a few cases that are handled separately or are
 * harmless.  It wraps each domain to increment gnum and invalidate on-CPU
 * contexts, and forces cnum to its max.  As a result of this call all user
 * threads that are running on CPUs trap and try to perform wrap around but
 * can't because hat_locks are taken.  Threads that were not on CPUs but started
 * by scheduler go to sfmmu_alloc_ctx() to aquire context without checking
 * hat_lock, but fail, because cnum == nctxs, and therefore also trap and block
 * on hat_lock trying to wrap.  sfmmu_ctxdom_lock() must be called before CPUs
 * are paused, else it could deadlock acquiring locks held by paused CPUs.
 *
 * sfmmu_ctxdoms_remove() removes context domains from every CPUs and records
 * the CPUs that had them.  It must be called after CPUs have been paused. This
 * ensures that no threads are in sfmmu_alloc_ctx() accessing domain data,
 * because pause_cpus sends a mondo interrupt to every CPU, and sfmmu_alloc_ctx
 * runs with interrupts disabled.  When CPUs are later resumed, they may enter
 * sfmmu_alloc_ctx, but it will check for CPU_MMU_CTXP = NULL and immediately
 * return failure.  Or, they will be blocked trying to acquire hat_lock. Thus
 * after sfmmu_ctxdoms_remove returns, we are guaranteed that no one is
 * accessing the old context domains.
 *
 * sfmmu_ctxdoms_update(void) frees space used by old context domains and
 * allocates new context domains based on hardware layout.  It initializes
 * every CPU that had context domain before migration to have one again.
 * sfmmu_ctxdoms_update must be called after CPUs are resumed, else it
 * could deadlock acquiring locks held by paused CPUs.
 *
 * sfmmu_ctxdoms_unlock(void) releases all hat_locks after which user threads
 * acquire new context ids and continue execution.
 *
 * Therefore functions should be called in the following order:
 *       suspend_routine()
 *              sfmmu_ctxdom_lock()
 *              pause_cpus()
 *              suspend()
 *                      if (suspend failed)
 *                              sfmmu_ctxdom_unlock()
 *              ...
 *              sfmmu_ctxdom_remove()
 *              resume_cpus()
 *              sfmmu_ctxdom_update()
 *              sfmmu_ctxdom_unlock()
 */
static cpuset_t sfmmu_ctxdoms_pset;

void
sfmmu_ctxdoms_remove()
{
        processorid_t   id;
        cpu_t           *cp;

        /*
         * Record the CPUs that have domains in sfmmu_ctxdoms_pset, so they can
         * be restored post-migration. A CPU may be powered off and not have a
         * domain, for example.
         */
        CPUSET_ZERO(sfmmu_ctxdoms_pset);

        for (id = 0; id < NCPU; id++) {
                if ((cp = cpu[id]) != NULL && CPU_MMU_CTXP(cp) != NULL) {
                        CPUSET_ADD(sfmmu_ctxdoms_pset, id);
                        CPU_MMU_CTXP(cp) = NULL;
                }
        }
}

void
sfmmu_ctxdoms_lock(void)
{
        int             idx;
        mmu_ctx_t       *mmu_ctxp;

        sfmmu_hat_lock_all();

        /*
         * At this point, no thread can be in sfmmu_ctx_wrap_around, because
         * hat_lock is always taken before calling it.
         *
         * For each domain, set mmu_cnum to max so no more contexts can be
         * allocated, and wrap to flush on-CPU contexts and force threads to
         * acquire a new context when we later drop hat_lock after migration.
         * Setting mmu_cnum may race with sfmmu_alloc_ctx which also sets cnum,
         * but the latter uses CAS and will miscompare and not overwrite it.
         */
        kpreempt_disable(); /* required by sfmmu_ctx_wrap_around */
        for (idx = 0; idx < max_mmu_ctxdoms; idx++) {
                if ((mmu_ctxp = mmu_ctxs_tbl[idx]) != NULL) {
                        mutex_enter(&mmu_ctxp->mmu_lock);
                        mmu_ctxp->mmu_cnum = mmu_ctxp->mmu_nctxs;
                        /* make sure updated cnum visible */
                        membar_enter();
                        mutex_exit(&mmu_ctxp->mmu_lock);
                        sfmmu_ctx_wrap_around(mmu_ctxp, B_FALSE);
                }
        }
        kpreempt_enable();
}

void
sfmmu_ctxdoms_unlock(void)
{
        sfmmu_hat_unlock_all();
}

void
sfmmu_ctxdoms_update(void)
{
        processorid_t   id;
        cpu_t           *cp;
        uint_t          idx;
        mmu_ctx_t       *mmu_ctxp;

        /*
         * Free all context domains.  As side effect, this increases
         * mmu_saved_gnum to the maximum gnum over all domains, which is used to
         * init gnum in the new domains, which therefore will be larger than the
         * sfmmu gnum for any process, guaranteeing that every process will see
         * a new generation and allocate a new context regardless of what new
         * domain it runs in.
         */
        mutex_enter(&cpu_lock);

        for (idx = 0; idx < max_mmu_ctxdoms; idx++) {
                if (mmu_ctxs_tbl[idx] != NULL) {
                        mmu_ctxp = mmu_ctxs_tbl[idx];
                        mmu_ctxs_tbl[idx] = NULL;
                        sfmmu_ctxdom_free(mmu_ctxp);
                }
        }

        for (id = 0; id < NCPU; id++) {
                if (CPU_IN_SET(sfmmu_ctxdoms_pset, id) &&
                    (cp = cpu[id]) != NULL)
                        sfmmu_cpu_init(cp);
        }
        mutex_exit(&cpu_lock);
}
#endif

/*
 * Hat_setup, makes an address space context the current active one.
 * In sfmmu this translates to setting the secondary context with the
 * corresponding context.
 */
void
hat_setup(struct hat *sfmmup, int allocflag)
{
        hatlock_t *hatlockp;

        /* Init needs some special treatment. */
        if (allocflag == HAT_INIT) {
                /*
                 * Make sure that we have
                 * 1. a TSB
                 * 2. a valid ctx that doesn't get stolen after this point.
                 */
                hatlockp = sfmmu_hat_enter(sfmmup);

                /*
                 * Swap in the TSB.  hat_init() allocates tsbinfos without
                 * TSBs, but we need one for init, since the kernel does some
                 * special things to set up its stack and needs the TSB to
                 * resolve page faults.
                 */
                sfmmu_tsb_swapin(sfmmup, hatlockp);

                sfmmu_get_ctx(sfmmup);

                sfmmu_hat_exit(hatlockp);
        } else {
                ASSERT(allocflag == HAT_ALLOC);

                hatlockp = sfmmu_hat_enter(sfmmup);
                kpreempt_disable();

                CPUSET_ADD(sfmmup->sfmmu_cpusran, CPU->cpu_id);
                /*
                 * sfmmu_setctx_sec takes <pgsz|cnum> as a parameter,
                 * pagesize bits don't matter in this case since we are passing
                 * INVALID_CONTEXT to it.
                 * Compatibility Note: hw takes care of MMU_SCONTEXT1
                 */
                sfmmu_setctx_sec(INVALID_CONTEXT);
                sfmmu_clear_utsbinfo();

                kpreempt_enable();
                sfmmu_hat_exit(hatlockp);
        }
}

/*
 * Free all the translation resources for the specified address space.
 * Called from as_free when an address space is being destroyed.
 */
void
hat_free_start(struct hat *sfmmup)
{
        ASSERT(AS_WRITE_HELD(sfmmup->sfmmu_as));
        ASSERT(sfmmup != ksfmmup);

        sfmmup->sfmmu_free = 1;
        if (sfmmup->sfmmu_scdp != NULL) {
                sfmmu_leave_scd(sfmmup, 0);
        }

        ASSERT(sfmmup->sfmmu_scdp == NULL);
}

void
hat_free_end(struct hat *sfmmup)
{
        int i;

        ASSERT(sfmmup->sfmmu_free == 1);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE8K] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE64K] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE512K] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE4M] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE32M] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE256M] == 0);

        if (sfmmup->sfmmu_rmstat) {
                hat_freestat(sfmmup->sfmmu_as, 0);
        }

        while (sfmmup->sfmmu_tsb != NULL) {
                struct tsb_info *next = sfmmup->sfmmu_tsb->tsb_next;
                sfmmu_tsbinfo_free(sfmmup->sfmmu_tsb);
                sfmmup->sfmmu_tsb = next;
        }

        if (sfmmup->sfmmu_srdp != NULL) {
                sfmmu_leave_srd(sfmmup);
                ASSERT(sfmmup->sfmmu_srdp == NULL);
                for (i = 0; i < SFMMU_L1_HMERLINKS; i++) {
                        if (sfmmup->sfmmu_hmeregion_links[i] != NULL) {
                                kmem_free(sfmmup->sfmmu_hmeregion_links[i],
                                    SFMMU_L2_HMERLINKS_SIZE);
                                sfmmup->sfmmu_hmeregion_links[i] = NULL;
                        }
                }
        }
        sfmmu_free_sfmmu(sfmmup);

#ifdef DEBUG
        for (i = 0; i < SFMMU_L1_HMERLINKS; i++) {
                ASSERT(sfmmup->sfmmu_hmeregion_links[i] == NULL);
        }
#endif

        kmem_cache_free(sfmmuid_cache, sfmmup);
}

/*
 * Set up any translation structures, for the specified address space,
 * that are needed or preferred when the process is being swapped in.
 */
/* ARGSUSED */
void
hat_swapin(struct hat *hat)
{
}

/*
 * Free all of the translation resources, for the specified address space,
 * that can be freed while the process is swapped out. Called from as_swapout.
 * Also, free up the ctx that this process was using.
 */
void
hat_swapout(struct hat *sfmmup)
{
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        struct hme_blk *pr_hblk = NULL;
        struct hme_blk *nx_hblk;
        int i;
        struct hme_blk *list = NULL;
        hatlock_t *hatlockp;
        struct tsb_info *tsbinfop;
        struct free_tsb {
                struct free_tsb *next;
                struct tsb_info *tsbinfop;
        };                      /* free list of TSBs */
        struct free_tsb *freelist, *last, *next;

        SFMMU_STAT(sf_swapout);

        /*
         * There is no way to go from an as to all its translations in sfmmu.
         * Here is one of the times when we take the big hit and traverse
         * the hash looking for hme_blks to free up.  Not only do we free up
         * this as hme_blks but all those that are free.  We are obviously
         * swapping because we need memory so let's free up as much
         * as we can.
         *
         * Note that we don't flush TLB/TSB here -- it's not necessary
         * because:
         *  1) we free the ctx we're using and throw away the TSB(s);
         *  2) processes aren't runnable while being swapped out.
         */
        ASSERT(sfmmup != KHATID);
        for (i = 0; i <= UHMEHASH_SZ; i++) {
                hmebp = &uhme_hash[i];
                SFMMU_HASH_LOCK(hmebp);
                hmeblkp = hmebp->hmeblkp;
                pr_hblk = NULL;
                while (hmeblkp) {

                        if ((hmeblkp->hblk_tag.htag_id == sfmmup) &&
                            !hmeblkp->hblk_shw_bit && !hmeblkp->hblk_lckcnt) {
                                ASSERT(!hmeblkp->hblk_shared);
                                (void) sfmmu_hblk_unload(sfmmup, hmeblkp,
                                    (caddr_t)get_hblk_base(hmeblkp),
                                    get_hblk_endaddr(hmeblkp),
                                    NULL, HAT_UNLOAD);
                        }
                        nx_hblk = hmeblkp->hblk_next;
                        if (!hmeblkp->hblk_vcnt && !hmeblkp->hblk_hmecnt) {
                                ASSERT(!hmeblkp->hblk_lckcnt);
                                sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk,
                                    &list, 0);
                        } else {
                                pr_hblk = hmeblkp;
                        }
                        hmeblkp = nx_hblk;
                }
                SFMMU_HASH_UNLOCK(hmebp);
        }

        sfmmu_hblks_list_purge(&list, 0);

        /*
         * Now free up the ctx so that others can reuse it.
         */
        hatlockp = sfmmu_hat_enter(sfmmup);

        sfmmu_invalidate_ctx(sfmmup);

        /*
         * Free TSBs, but not tsbinfos, and set SWAPPED flag.
         * If TSBs were never swapped in, just return.
         * This implies that we don't support partial swapping
         * of TSBs -- either all are swapped out, or none are.
         *
         * We must hold the HAT lock here to prevent racing with another
         * thread trying to unmap TTEs from the TSB or running the post-
         * relocator after relocating the TSB's memory.  Unfortunately, we
         * can't free memory while holding the HAT lock or we could
         * deadlock, so we build a list of TSBs to be freed after marking
         * the tsbinfos as swapped out and free them after dropping the
         * lock.
         */
        if (SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPPED)) {
                sfmmu_hat_exit(hatlockp);
                return;
        }

        SFMMU_FLAGS_SET(sfmmup, HAT_SWAPPED);
        last = freelist = NULL;
        for (tsbinfop = sfmmup->sfmmu_tsb; tsbinfop != NULL;
            tsbinfop = tsbinfop->tsb_next) {
                ASSERT((tsbinfop->tsb_flags & TSB_SWAPPED) == 0);

                /*
                 * Cast the TSB into a struct free_tsb and put it on the free
                 * list.
                 */
                if (freelist == NULL) {
                        last = freelist = (struct free_tsb *)tsbinfop->tsb_va;
                } else {
                        last->next = (struct free_tsb *)tsbinfop->tsb_va;
                        last = last->next;
                }
                last->next = NULL;
                last->tsbinfop = tsbinfop;
                tsbinfop->tsb_flags |= TSB_SWAPPED;
                /*
                 * Zero out the TTE to clear the valid bit.
                 * Note we can't use a value like 0xbad because we want to
                 * ensure diagnostic bits are NEVER set on TTEs that might
                 * be loaded.  The intent is to catch any invalid access
                 * to the swapped TSB, such as a thread running with a valid
                 * context without first calling sfmmu_tsb_swapin() to
                 * allocate TSB memory.
                 */
                tsbinfop->tsb_tte.ll = 0;
        }

        /* Now we can drop the lock and free the TSB memory. */
        sfmmu_hat_exit(hatlockp);
        for (; freelist != NULL; freelist = next) {
                next = freelist->next;
                sfmmu_tsb_free(freelist->tsbinfop);
        }
}

/*
 * Duplicate the translations of an as into another newas
 */
/* ARGSUSED */
int
hat_dup(struct hat *hat, struct hat *newhat, caddr_t addr, size_t len,
    uint_t flag)
{
        sf_srd_t *srdp;
        sf_scd_t *scdp;
        int i;
        extern uint_t get_color_start(struct as *);

        ASSERT((flag == 0) || (flag == HAT_DUP_ALL) || (flag == HAT_DUP_COW) ||
            (flag == HAT_DUP_SRD));
        ASSERT(hat != ksfmmup);
        ASSERT(newhat != ksfmmup);
        ASSERT(flag != HAT_DUP_ALL || hat->sfmmu_srdp == newhat->sfmmu_srdp);

        if (flag == HAT_DUP_COW) {
                panic("hat_dup: HAT_DUP_COW not supported");
        }

        if (flag == HAT_DUP_SRD && ((srdp = hat->sfmmu_srdp) != NULL)) {
                ASSERT(srdp->srd_evp != NULL);
                VN_HOLD(srdp->srd_evp);
                ASSERT(srdp->srd_refcnt > 0);
                newhat->sfmmu_srdp = srdp;
                atomic_inc_32((volatile uint_t *)&srdp->srd_refcnt);
        }

        /*
         * HAT_DUP_ALL flag is used after as duplication is done.
         */
        if (flag == HAT_DUP_ALL && ((srdp = newhat->sfmmu_srdp) != NULL)) {
                ASSERT(newhat->sfmmu_srdp->srd_refcnt >= 2);
                newhat->sfmmu_rtteflags = hat->sfmmu_rtteflags;
                if (hat->sfmmu_flags & HAT_4MTEXT_FLAG) {
                        newhat->sfmmu_flags |= HAT_4MTEXT_FLAG;
                }

                /* check if need to join scd */
                if ((scdp = hat->sfmmu_scdp) != NULL &&
                    newhat->sfmmu_scdp != scdp) {
                        int ret;
                        SF_RGNMAP_IS_SUBSET(&newhat->sfmmu_region_map,
                            &scdp->scd_region_map, ret);
                        ASSERT(ret);
                        sfmmu_join_scd(scdp, newhat);
                        ASSERT(newhat->sfmmu_scdp == scdp &&
                            scdp->scd_refcnt >= 2);
                        for (i = 0; i < max_mmu_page_sizes; i++) {
                                newhat->sfmmu_ismttecnt[i] =
                                    hat->sfmmu_ismttecnt[i];
                                newhat->sfmmu_scdismttecnt[i] =
                                    hat->sfmmu_scdismttecnt[i];
                        }
                }

                sfmmu_check_page_sizes(newhat, 1);
        }

        if (flag == HAT_DUP_ALL && consistent_coloring == 0 &&
            update_proc_pgcolorbase_after_fork != 0) {
                hat->sfmmu_clrbin = get_color_start(hat->sfmmu_as);
        }
        return (0);
}

void
hat_memload(struct hat *hat, caddr_t addr, struct page *pp,
    uint_t attr, uint_t flags)
{
        hat_do_memload(hat, addr, pp, attr, flags,
            SFMMU_INVALID_SHMERID);
}

void
hat_memload_region(struct hat *hat, caddr_t addr, struct page *pp,
    uint_t attr, uint_t flags, hat_region_cookie_t rcookie)
{
        uint_t rid;
        if (rcookie == HAT_INVALID_REGION_COOKIE) {
                hat_do_memload(hat, addr, pp, attr, flags,
                    SFMMU_INVALID_SHMERID);
                return;
        }
        rid = (uint_t)((uint64_t)rcookie);
        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
        hat_do_memload(hat, addr, pp, attr, flags, rid);
}

/*
 * Set up addr to map to page pp with protection prot.
 * As an optimization we also load the TSB with the
 * corresponding tte but it is no big deal if  the tte gets kicked out.
 */
static void
hat_do_memload(struct hat *hat, caddr_t addr, struct page *pp,
    uint_t attr, uint_t flags, uint_t rid)
{
        tte_t tte;


        ASSERT(hat != NULL);
        ASSERT(PAGE_LOCKED(pp));
        ASSERT(!((uintptr_t)addr & MMU_PAGEOFFSET));
        ASSERT(!(flags & ~SFMMU_LOAD_ALLFLAG));
        ASSERT(!(attr & ~SFMMU_LOAD_ALLATTR));
        SFMMU_VALIDATE_HMERID(hat, rid, addr, MMU_PAGESIZE);

        if (PP_ISFREE(pp)) {
                panic("hat_memload: loading a mapping to free page %p",
                    (void *)pp);
        }

        ASSERT((hat == ksfmmup) || AS_LOCK_HELD(hat->sfmmu_as));

        if (flags & ~SFMMU_LOAD_ALLFLAG)
                cmn_err(CE_NOTE, "hat_memload: unsupported flags %d",
                    flags & ~SFMMU_LOAD_ALLFLAG);

        if (hat->sfmmu_rmstat)
                hat_resvstat(MMU_PAGESIZE, hat->sfmmu_as, addr);

#if defined(SF_ERRATA_57)
        if ((hat != ksfmmup) && AS_TYPE_64BIT(hat->sfmmu_as) &&
            (addr < errata57_limit) && (attr & PROT_EXEC) &&
            !(flags & HAT_LOAD_SHARE)) {
                cmn_err(CE_WARN, "hat_memload: illegal attempt to make user "
                    " page executable");
                attr &= ~PROT_EXEC;
        }
#endif

        sfmmu_memtte(&tte, pp->p_pagenum, attr, TTE8K);
        (void) sfmmu_tteload_array(hat, &tte, addr, &pp, flags, rid);

        /*
         * Check TSB and TLB page sizes.
         */
        if ((flags & HAT_LOAD_SHARE) == 0) {
                sfmmu_check_page_sizes(hat, 1);
        }
}

/*
 * hat_devload can be called to map real memory (e.g.
 * /dev/kmem) and even though hat_devload will determine pf is
 * for memory, it will be unable to get a shared lock on the
 * page (because someone else has it exclusively) and will
 * pass dp = NULL.  If tteload doesn't get a non-NULL
 * page pointer it can't cache memory.
 */
void
hat_devload(struct hat *hat, caddr_t addr, size_t len, pfn_t pfn,
    uint_t attr, int flags)
{
        tte_t tte;
        struct page *pp = NULL;
        int use_lgpg = 0;

        ASSERT(hat != NULL);

        ASSERT(!(flags & ~SFMMU_LOAD_ALLFLAG));
        ASSERT(!(attr & ~SFMMU_LOAD_ALLATTR));
        ASSERT((hat == ksfmmup) || AS_LOCK_HELD(hat->sfmmu_as));
        if (len == 0)
                panic("hat_devload: zero len");
        if (flags & ~SFMMU_LOAD_ALLFLAG)
                cmn_err(CE_NOTE, "hat_devload: unsupported flags %d",
                    flags & ~SFMMU_LOAD_ALLFLAG);

#if defined(SF_ERRATA_57)
        if ((hat != ksfmmup) && AS_TYPE_64BIT(hat->sfmmu_as) &&
            (addr < errata57_limit) && (attr & PROT_EXEC) &&
            !(flags & HAT_LOAD_SHARE)) {
                cmn_err(CE_WARN, "hat_devload: illegal attempt to make user "
                    " page executable");
                attr &= ~PROT_EXEC;
        }
#endif

        /*
         * If it's a memory page find its pp
         */
        if (!(flags & HAT_LOAD_NOCONSIST) && pf_is_memory(pfn)) {
                pp = page_numtopp_nolock(pfn);
                if (pp == NULL) {
                        flags |= HAT_LOAD_NOCONSIST;
                } else {
                        if (PP_ISFREE(pp)) {
                                panic("hat_memload: loading "
                                    "a mapping to free page %p",
                                    (void *)pp);
                        }
                        if (!PAGE_LOCKED(pp) && !PP_ISNORELOC(pp)) {
                                panic("hat_memload: loading a mapping "
                                    "to unlocked relocatable page %p",
                                    (void *)pp);
                        }
                        ASSERT(len == MMU_PAGESIZE);
                }
        }

        if (hat->sfmmu_rmstat)
                hat_resvstat(len, hat->sfmmu_as, addr);

        if (flags & HAT_LOAD_NOCONSIST) {
                attr |= SFMMU_UNCACHEVTTE;
                use_lgpg = 1;
        }
        if (!pf_is_memory(pfn)) {
                attr |= SFMMU_UNCACHEPTTE | HAT_NOSYNC;
                use_lgpg = 1;
                switch (attr & HAT_ORDER_MASK) {
                        case HAT_STRICTORDER:
                        case HAT_UNORDERED_OK:
                                /*
                                 * we set the side effect bit for all non
                                 * memory mappings unless merging is ok
                                 */
                                attr |= SFMMU_SIDEFFECT;
                                break;
                        case HAT_MERGING_OK:
                        case HAT_LOADCACHING_OK:
                        case HAT_STORECACHING_OK:
                                break;
                        default:
                                panic("hat_devload: bad attr");
                                break;
                }
        }
        while (len) {
                if (!use_lgpg) {
                        sfmmu_memtte(&tte, pfn, attr, TTE8K);
                        (void) sfmmu_tteload_array(hat, &tte, addr, &pp,
                            flags, SFMMU_INVALID_SHMERID);
                        len -= MMU_PAGESIZE;
                        addr += MMU_PAGESIZE;
                        pfn++;
                        continue;
                }
                /*
                 *  try to use large pages, check va/pa alignments
                 *  Note that 32M/256M page sizes are not (yet) supported.
                 */
                if ((len >= MMU_PAGESIZE4M) &&
                    !((uintptr_t)addr & MMU_PAGEOFFSET4M) &&
                    !(disable_large_pages & (1 << TTE4M)) &&
                    !(mmu_ptob(pfn) & MMU_PAGEOFFSET4M)) {
                        sfmmu_memtte(&tte, pfn, attr, TTE4M);
                        (void) sfmmu_tteload_array(hat, &tte, addr, &pp,
                            flags, SFMMU_INVALID_SHMERID);
                        len -= MMU_PAGESIZE4M;
                        addr += MMU_PAGESIZE4M;
                        pfn += MMU_PAGESIZE4M / MMU_PAGESIZE;
                } else if ((len >= MMU_PAGESIZE512K) &&
                    !((uintptr_t)addr & MMU_PAGEOFFSET512K) &&
                    !(disable_large_pages & (1 << TTE512K)) &&
                    !(mmu_ptob(pfn) & MMU_PAGEOFFSET512K)) {
                        sfmmu_memtte(&tte, pfn, attr, TTE512K);
                        (void) sfmmu_tteload_array(hat, &tte, addr, &pp,
                            flags, SFMMU_INVALID_SHMERID);
                        len -= MMU_PAGESIZE512K;
                        addr += MMU_PAGESIZE512K;
                        pfn += MMU_PAGESIZE512K / MMU_PAGESIZE;
                } else if ((len >= MMU_PAGESIZE64K) &&
                    !((uintptr_t)addr & MMU_PAGEOFFSET64K) &&
                    !(disable_large_pages & (1 << TTE64K)) &&
                    !(mmu_ptob(pfn) & MMU_PAGEOFFSET64K)) {
                        sfmmu_memtte(&tte, pfn, attr, TTE64K);
                        (void) sfmmu_tteload_array(hat, &tte, addr, &pp,
                            flags, SFMMU_INVALID_SHMERID);
                        len -= MMU_PAGESIZE64K;
                        addr += MMU_PAGESIZE64K;
                        pfn += MMU_PAGESIZE64K / MMU_PAGESIZE;
                } else {
                        sfmmu_memtte(&tte, pfn, attr, TTE8K);
                        (void) sfmmu_tteload_array(hat, &tte, addr, &pp,
                            flags, SFMMU_INVALID_SHMERID);
                        len -= MMU_PAGESIZE;
                        addr += MMU_PAGESIZE;
                        pfn++;
                }
        }

        /*
         * Check TSB and TLB page sizes.
         */
        if ((flags & HAT_LOAD_SHARE) == 0) {
                sfmmu_check_page_sizes(hat, 1);
        }
}

void
hat_memload_array(struct hat *hat, caddr_t addr, size_t len,
    struct page **pps, uint_t attr, uint_t flags)
{
        hat_do_memload_array(hat, addr, len, pps, attr, flags,
            SFMMU_INVALID_SHMERID);
}

void
hat_memload_array_region(struct hat *hat, caddr_t addr, size_t len,
    struct page **pps, uint_t attr, uint_t flags,
    hat_region_cookie_t rcookie)
{
        uint_t rid;
        if (rcookie == HAT_INVALID_REGION_COOKIE) {
                hat_do_memload_array(hat, addr, len, pps, attr, flags,
                    SFMMU_INVALID_SHMERID);
                return;
        }
        rid = (uint_t)((uint64_t)rcookie);
        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
        hat_do_memload_array(hat, addr, len, pps, attr, flags, rid);
}

/*
 * Map the largest extend possible out of the page array. The array may NOT
 * be in order.  The largest possible mapping a page can have
 * is specified in the p_szc field.  The p_szc field
 * cannot change as long as there any mappings (large or small)
 * to any of the pages that make up the large page. (ie. any
 * promotion/demotion of page size is not up to the hat but up to
 * the page free list manager).  The array
 * should consist of properly aligned contigous pages that are
 * part of a big page for a large mapping to be created.
 */
static void
hat_do_memload_array(struct hat *hat, caddr_t addr, size_t len,
    struct page **pps, uint_t attr, uint_t flags, uint_t rid)
{
        int  ttesz;
        size_t mapsz;
        pgcnt_t numpg, npgs;
        tte_t tte;
        page_t *pp;
        uint_t large_pages_disable;

        ASSERT(!((uintptr_t)addr & MMU_PAGEOFFSET));
        SFMMU_VALIDATE_HMERID(hat, rid, addr, len);

        if (hat->sfmmu_rmstat)
                hat_resvstat(len, hat->sfmmu_as, addr);

#if defined(SF_ERRATA_57)
        if ((hat != ksfmmup) && AS_TYPE_64BIT(hat->sfmmu_as) &&
            (addr < errata57_limit) && (attr & PROT_EXEC) &&
            !(flags & HAT_LOAD_SHARE)) {
                cmn_err(CE_WARN, "hat_memload_array: illegal attempt to make "
                    "user page executable");
                attr &= ~PROT_EXEC;
        }
#endif

        /* Get number of pages */
        npgs = len >> MMU_PAGESHIFT;

        if (flags & HAT_LOAD_SHARE) {
                large_pages_disable = disable_ism_large_pages;
        } else {
                large_pages_disable = disable_large_pages;
        }

        if (npgs < NHMENTS || large_pages_disable == LARGE_PAGES_OFF) {
                sfmmu_memload_batchsmall(hat, addr, pps, attr, flags, npgs,
                    rid);
                return;
        }

        while (npgs >= NHMENTS) {
                pp = *pps;
                for (ttesz = pp->p_szc; ttesz != TTE8K; ttesz--) {
                        /*
                         * Check if this page size is disabled.
                         */
                        if (large_pages_disable & (1 << ttesz))
                                continue;

                        numpg = TTEPAGES(ttesz);
                        mapsz = numpg << MMU_PAGESHIFT;
                        if ((npgs >= numpg) &&
                            IS_P2ALIGNED(addr, mapsz) &&
                            IS_P2ALIGNED(pp->p_pagenum, numpg)) {
                                /*
                                 * At this point we have enough pages and
                                 * we know the virtual address and the pfn
                                 * are properly aligned.  We still need
                                 * to check for physical contiguity but since
                                 * it is very likely that this is the case
                                 * we will assume they are so and undo
                                 * the request if necessary.  It would
                                 * be great if we could get a hint flag
                                 * like HAT_CONTIG which would tell us
                                 * the pages are contigous for sure.
                                 */
                                sfmmu_memtte(&tte, (*pps)->p_pagenum,
                                    attr, ttesz);
                                if (!sfmmu_tteload_array(hat, &tte, addr,
                                    pps, flags, rid)) {
                                        break;
                                }
                        }
                }
                if (ttesz == TTE8K) {
                        /*
                         * We were not able to map array using a large page
                         * batch a hmeblk or fraction at a time.
                         */
                        numpg = ((uintptr_t)addr >> MMU_PAGESHIFT)
                            & (NHMENTS-1);
                        numpg = NHMENTS - numpg;
                        ASSERT(numpg <= npgs);
                        mapsz = numpg * MMU_PAGESIZE;
                        sfmmu_memload_batchsmall(hat, addr, pps, attr, flags,
                            numpg, rid);
                }
                addr += mapsz;
                npgs -= numpg;
                pps += numpg;
        }

        if (npgs) {
                sfmmu_memload_batchsmall(hat, addr, pps, attr, flags, npgs,
                    rid);
        }

        /*
         * Check TSB and TLB page sizes.
         */
        if ((flags & HAT_LOAD_SHARE) == 0) {
                sfmmu_check_page_sizes(hat, 1);
        }
}

/*
 * Function tries to batch 8K pages into the same hme blk.
 */
static void
sfmmu_memload_batchsmall(struct hat *hat, caddr_t vaddr, page_t **pps,
    uint_t attr, uint_t flags, pgcnt_t npgs, uint_t rid)
{
        tte_t   tte;
        page_t *pp;
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        int     index;

        while (npgs) {
                /*
                 * Acquire the hash bucket.
                 */
                hmebp = sfmmu_tteload_acquire_hashbucket(hat, vaddr, TTE8K,
                    rid);
                ASSERT(hmebp);

                /*
                 * Find the hment block.
                 */
                hmeblkp = sfmmu_tteload_find_hmeblk(hat, hmebp, vaddr,
                    TTE8K, flags, rid);
                ASSERT(hmeblkp);

                do {
                        /*
                         * Make the tte.
                         */
                        pp = *pps;
                        sfmmu_memtte(&tte, pp->p_pagenum, attr, TTE8K);

                        /*
                         * Add the translation.
                         */
                        (void) sfmmu_tteload_addentry(hat, hmeblkp, &tte,
                            vaddr, pps, flags, rid);

                        /*
                         * Goto next page.
                         */
                        pps++;
                        npgs--;

                        /*
                         * Goto next address.
                         */
                        vaddr += MMU_PAGESIZE;

                        /*
                         * Don't crossover into a different hmentblk.
                         */
                        index = (int)(((uintptr_t)vaddr >> MMU_PAGESHIFT) &
                            (NHMENTS-1));

                } while (index != 0 && npgs != 0);

                /*
                 * Release the hash bucket.
                 */

                sfmmu_tteload_release_hashbucket(hmebp);
        }
}

/*
 * Construct a tte for a page:
 *
 * tte_valid = 1
 * tte_size2 = size & TTE_SZ2_BITS (Panther and Olympus-C only)
 * tte_size = size
 * tte_nfo = attr & HAT_NOFAULT
 * tte_ie = attr & HAT_STRUCTURE_LE
 * tte_hmenum = hmenum
 * tte_pahi = pp->p_pagenum >> TTE_PASHIFT;
 * tte_palo = pp->p_pagenum & TTE_PALOMASK;
 * tte_ref = 1 (optimization)
 * tte_wr_perm = attr & PROT_WRITE;
 * tte_no_sync = attr & HAT_NOSYNC
 * tte_lock = attr & SFMMU_LOCKTTE
 * tte_cp = !(attr & SFMMU_UNCACHEPTTE)
 * tte_cv = !(attr & SFMMU_UNCACHEVTTE)
 * tte_e = attr & SFMMU_SIDEFFECT
 * tte_priv = !(attr & PROT_USER)
 * tte_hwwr = if nosync is set and it is writable we set the mod bit (opt)
 * tte_glb = 0
 */
void
sfmmu_memtte(tte_t *ttep, pfn_t pfn, uint_t attr, int tte_sz)
{
        ASSERT(!(attr & ~SFMMU_LOAD_ALLATTR));

        ttep->tte_inthi = MAKE_TTE_INTHI(pfn, attr, tte_sz, 0 /* hmenum */);
        ttep->tte_intlo = MAKE_TTE_INTLO(pfn, attr, tte_sz, 0 /* hmenum */);

        if (TTE_IS_NOSYNC(ttep)) {
                TTE_SET_REF(ttep);
                if (TTE_IS_WRITABLE(ttep)) {
                        TTE_SET_MOD(ttep);
                }
        }
        if (TTE_IS_NFO(ttep) && TTE_IS_EXECUTABLE(ttep)) {
                panic("sfmmu_memtte: can't set both NFO and EXEC bits");
        }
}

/*
 * This function will add a translation to the hme_blk and allocate the
 * hme_blk if one does not exist.
 * If a page structure is specified then it will add the
 * corresponding hment to the mapping list.
 * It will also update the hmenum field for the tte.
 *
 * Currently this function is only used for kernel mappings.
 * So pass invalid region to sfmmu_tteload_array().
 */
void
sfmmu_tteload(struct hat *sfmmup, tte_t *ttep, caddr_t vaddr, page_t *pp,
    uint_t flags)
{
        ASSERT(sfmmup == ksfmmup);
        (void) sfmmu_tteload_array(sfmmup, ttep, vaddr, &pp, flags,
            SFMMU_INVALID_SHMERID);
}

/*
 * Load (ttep != NULL) or unload (ttep == NULL) one entry in the TSB.
 * Assumes that a particular page size may only be resident in one TSB.
 */
static void
sfmmu_mod_tsb(sfmmu_t *sfmmup, caddr_t vaddr, tte_t *ttep, int ttesz)
{
        struct tsb_info *tsbinfop = NULL;
        uint64_t tag;
        struct tsbe *tsbe_addr;
        uint64_t tsb_base;
        uint_t tsb_size;
        int vpshift = MMU_PAGESHIFT;
        int phys = 0;

        if (sfmmup == ksfmmup) { /* No support for 32/256M ksfmmu pages */
                phys = ktsb_phys;
                if (ttesz >= TTE4M) {
#ifndef sun4v
                        ASSERT((ttesz != TTE32M) && (ttesz != TTE256M));
#endif
                        tsb_base = (phys)? ktsb4m_pbase : (uint64_t)ktsb4m_base;
                        tsb_size = ktsb4m_szcode;
                } else {
                        tsb_base = (phys)? ktsb_pbase : (uint64_t)ktsb_base;
                        tsb_size = ktsb_szcode;
                }
        } else {
                SFMMU_GET_TSBINFO(tsbinfop, sfmmup, ttesz);

                /*
                 * If there isn't a TSB for this page size, or the TSB is
                 * swapped out, there is nothing to do.  Note that the latter
                 * case seems impossible but can occur if hat_pageunload()
                 * is called on an ISM mapping while the process is swapped
                 * out.
                 */
                if (tsbinfop == NULL || (tsbinfop->tsb_flags & TSB_SWAPPED))
                        return;

                /*
                 * If another thread is in the middle of relocating a TSB
                 * we can't unload the entry so set a flag so that the
                 * TSB will be flushed before it can be accessed by the
                 * process.
                 */
                if ((tsbinfop->tsb_flags & TSB_RELOC_FLAG) != 0) {
                        if (ttep == NULL)
                                tsbinfop->tsb_flags |= TSB_FLUSH_NEEDED;
                        return;
                }
#if defined(UTSB_PHYS)
                phys = 1;
                tsb_base = (uint64_t)tsbinfop->tsb_pa;
#else
                tsb_base = (uint64_t)tsbinfop->tsb_va;
#endif
                tsb_size = tsbinfop->tsb_szc;
        }
        if (ttesz >= TTE4M)
                vpshift = MMU_PAGESHIFT4M;

        tsbe_addr = sfmmu_get_tsbe(tsb_base, vaddr, vpshift, tsb_size);
        tag = sfmmu_make_tsbtag(vaddr);

        if (ttep == NULL) {
                sfmmu_unload_tsbe(tsbe_addr, tag, phys);
        } else {
                if (ttesz >= TTE4M) {
                        SFMMU_STAT(sf_tsb_load4m);
                } else {
                        SFMMU_STAT(sf_tsb_load8k);
                }

                sfmmu_load_tsbe(tsbe_addr, tag, ttep, phys);
        }
}

/*
 * Unmap all entries from [start, end) matching the given page size.
 *
 * This function is used primarily to unmap replicated 64K or 512K entries
 * from the TSB that are inserted using the base page size TSB pointer, but
 * it may also be called to unmap a range of addresses from the TSB.
 */
void
sfmmu_unload_tsb_range(sfmmu_t *sfmmup, caddr_t start, caddr_t end, int ttesz)
{
        struct tsb_info *tsbinfop;
        uint64_t tag;
        struct tsbe *tsbe_addr;
        caddr_t vaddr;
        uint64_t tsb_base;
        int vpshift, vpgsz;
        uint_t tsb_size;
        int phys = 0;

        /*
         * Assumptions:
         *  If ttesz == 8K, 64K or 512K, we walk through the range 8K
         *  at a time shooting down any valid entries we encounter.
         *
         *  If ttesz >= 4M we walk the range 4M at a time shooting
         *  down any valid mappings we find.
         */
        if (sfmmup == ksfmmup) {
                phys = ktsb_phys;
                if (ttesz >= TTE4M) {
#ifndef sun4v
                        ASSERT((ttesz != TTE32M) && (ttesz != TTE256M));
#endif
                        tsb_base = (phys)? ktsb4m_pbase : (uint64_t)ktsb4m_base;
                        tsb_size = ktsb4m_szcode;
                } else {
                        tsb_base = (phys)? ktsb_pbase : (uint64_t)ktsb_base;
                        tsb_size = ktsb_szcode;
                }
        } else {
                SFMMU_GET_TSBINFO(tsbinfop, sfmmup, ttesz);

                /*
                 * If there isn't a TSB for this page size, or the TSB is
                 * swapped out, there is nothing to do.  Note that the latter
                 * case seems impossible but can occur if hat_pageunload()
                 * is called on an ISM mapping while the process is swapped
                 * out.
                 */
                if (tsbinfop == NULL || (tsbinfop->tsb_flags & TSB_SWAPPED))
                        return;

                /*
                 * If another thread is in the middle of relocating a TSB
                 * we can't unload the entry so set a flag so that the
                 * TSB will be flushed before it can be accessed by the
                 * process.
                 */
                if ((tsbinfop->tsb_flags & TSB_RELOC_FLAG) != 0) {
                        tsbinfop->tsb_flags |= TSB_FLUSH_NEEDED;
                        return;
                }
#if defined(UTSB_PHYS)
                phys = 1;
                tsb_base = (uint64_t)tsbinfop->tsb_pa;
#else
                tsb_base = (uint64_t)tsbinfop->tsb_va;
#endif
                tsb_size = tsbinfop->tsb_szc;
        }
        if (ttesz >= TTE4M) {
                vpshift = MMU_PAGESHIFT4M;
                vpgsz = MMU_PAGESIZE4M;
        } else {
                vpshift = MMU_PAGESHIFT;
                vpgsz = MMU_PAGESIZE;
        }

        for (vaddr = start; vaddr < end; vaddr += vpgsz) {
                tag = sfmmu_make_tsbtag(vaddr);
                tsbe_addr = sfmmu_get_tsbe(tsb_base, vaddr, vpshift, tsb_size);
                sfmmu_unload_tsbe(tsbe_addr, tag, phys);
        }
}

/*
 * Select the optimum TSB size given the number of mappings
 * that need to be cached.
 */
static int
sfmmu_select_tsb_szc(pgcnt_t pgcnt)
{
        int szc = 0;

#ifdef DEBUG
        if (tsb_grow_stress) {
                uint32_t randval = (uint32_t)gettick() >> 4;
                return (randval % (tsb_max_growsize + 1));
        }
#endif  /* DEBUG */

        while ((szc < tsb_max_growsize) && (pgcnt > SFMMU_RSS_TSBSIZE(szc)))
                szc++;
        return (szc);
}

/*
 * This function will add a translation to the hme_blk and allocate the
 * hme_blk if one does not exist.
 * If a page structure is specified then it will add the
 * corresponding hment to the mapping list.
 * It will also update the hmenum field for the tte.
 * Furthermore, it attempts to create a large page translation
 * for <addr,hat> at page array pps.  It assumes addr and first
 * pp is correctly aligned.  It returns 0 if successful and 1 otherwise.
 */
static int
sfmmu_tteload_array(sfmmu_t *sfmmup, tte_t *ttep, caddr_t vaddr,
    page_t **pps, uint_t flags, uint_t rid)
{
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        int     ret;
        uint_t  size;

        /*
         * Get mapping size.
         */
        size = TTE_CSZ(ttep);
        ASSERT(!((uintptr_t)vaddr & TTE_PAGE_OFFSET(size)));

        /*
         * Acquire the hash bucket.
         */
        hmebp = sfmmu_tteload_acquire_hashbucket(sfmmup, vaddr, size, rid);
        ASSERT(hmebp);

        /*
         * Find the hment block.
         */
        hmeblkp = sfmmu_tteload_find_hmeblk(sfmmup, hmebp, vaddr, size, flags,
            rid);
        ASSERT(hmeblkp);

        /*
         * Add the translation.
         */
        ret = sfmmu_tteload_addentry(sfmmup, hmeblkp, ttep, vaddr, pps, flags,
            rid);

        /*
         * Release the hash bucket.
         */
        sfmmu_tteload_release_hashbucket(hmebp);

        return (ret);
}

/*
 * Function locks and returns a pointer to the hash bucket for vaddr and size.
 */
static struct hmehash_bucket *
sfmmu_tteload_acquire_hashbucket(sfmmu_t *sfmmup, caddr_t vaddr, int size,
    uint_t rid)
{
        struct hmehash_bucket *hmebp;
        int hmeshift;
        void *htagid = sfmmutohtagid(sfmmup, rid);

        ASSERT(htagid != NULL);

        hmeshift = HME_HASH_SHIFT(size);

        hmebp = HME_HASH_FUNCTION(htagid, vaddr, hmeshift);

        SFMMU_HASH_LOCK(hmebp);

        return (hmebp);
}

/*
 * Function returns a pointer to an hmeblk in the hash bucket, hmebp. If the
 * hmeblk doesn't exists for the [sfmmup, vaddr & size] signature, a hmeblk is
 * allocated.
 */
static struct hme_blk *
sfmmu_tteload_find_hmeblk(sfmmu_t *sfmmup, struct hmehash_bucket *hmebp,
    caddr_t vaddr, uint_t size, uint_t flags, uint_t rid)
{
        hmeblk_tag hblktag;
        int hmeshift;
        struct hme_blk *hmeblkp, *pr_hblk, *list = NULL;

        SFMMU_VALIDATE_HMERID(sfmmup, rid, vaddr, TTEBYTES(size));

        hblktag.htag_id = sfmmutohtagid(sfmmup, rid);
        ASSERT(hblktag.htag_id != NULL);
        hmeshift = HME_HASH_SHIFT(size);
        hblktag.htag_bspage = HME_HASH_BSPAGE(vaddr, hmeshift);
        hblktag.htag_rehash = HME_HASH_REHASH(size);
        hblktag.htag_rid = rid;

ttearray_realloc:

        HME_HASH_SEARCH_PREV(hmebp, hblktag, hmeblkp, pr_hblk, &list);

        /*
         * We block until hblk_reserve_lock is released; it's held by
         * the thread, temporarily using hblk_reserve, until hblk_reserve is
         * replaced by a hblk from sfmmu8_cache.
         */
        if (hmeblkp == (struct hme_blk *)hblk_reserve &&
            hblk_reserve_thread != curthread) {
                SFMMU_HASH_UNLOCK(hmebp);
                mutex_enter(&hblk_reserve_lock);
                mutex_exit(&hblk_reserve_lock);
                SFMMU_STAT(sf_hblk_reserve_hit);
                SFMMU_HASH_LOCK(hmebp);
                goto ttearray_realloc;
        }

        if (hmeblkp == NULL) {
                hmeblkp = sfmmu_hblk_alloc(sfmmup, vaddr, hmebp, size,
                    hblktag, flags, rid);
                ASSERT(!SFMMU_IS_SHMERID_VALID(rid) || hmeblkp->hblk_shared);
                ASSERT(SFMMU_IS_SHMERID_VALID(rid) || !hmeblkp->hblk_shared);
        } else {
                /*
                 * It is possible for 8k and 64k hblks to collide since they
                 * have the same rehash value. This is because we
                 * lazily free hblks and 8K/64K blks could be lingering.
                 * If we find size mismatch we free the block and & try again.
                 */
                if (get_hblk_ttesz(hmeblkp) != size) {
                        ASSERT(!hmeblkp->hblk_vcnt);
                        ASSERT(!hmeblkp->hblk_hmecnt);
                        sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk,
                            &list, 0);
                        goto ttearray_realloc;
                }
                if (hmeblkp->hblk_shw_bit) {
                        /*
                         * if the hblk was previously used as a shadow hblk then
                         * we will change it to a normal hblk
                         */
                        ASSERT(!hmeblkp->hblk_shared);
                        if (hmeblkp->hblk_shw_mask) {
                                sfmmu_shadow_hcleanup(sfmmup, hmeblkp, hmebp);
                                ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));
                                goto ttearray_realloc;
                        } else {
                                hmeblkp->hblk_shw_bit = 0;
                        }
                }
                SFMMU_STAT(sf_hblk_hit);
        }

        /*
         * hat_memload() should never call kmem_cache_free() for kernel hmeblks;
         * see block comment showing the stacktrace in sfmmu_hblk_alloc();
         * set the flag parameter to 1 so that sfmmu_hblks_list_purge() will
         * just add these hmeblks to the per-cpu pending queue.
         */
        sfmmu_hblks_list_purge(&list, 1);

        ASSERT(get_hblk_ttesz(hmeblkp) == size);
        ASSERT(!hmeblkp->hblk_shw_bit);
        ASSERT(!SFMMU_IS_SHMERID_VALID(rid) || hmeblkp->hblk_shared);
        ASSERT(SFMMU_IS_SHMERID_VALID(rid) || !hmeblkp->hblk_shared);
        ASSERT(hmeblkp->hblk_tag.htag_rid == rid);

        return (hmeblkp);
}

/*
 * Function adds a tte entry into the hmeblk. It returns 0 if successful and 1
 * otherwise.
 */
static int
sfmmu_tteload_addentry(sfmmu_t *sfmmup, struct hme_blk *hmeblkp, tte_t *ttep,
    caddr_t vaddr, page_t **pps, uint_t flags, uint_t rid)
{
        page_t *pp = *pps;
        int hmenum, size, remap;
        tte_t tteold, flush_tte;
#ifdef DEBUG
        tte_t orig_old;
#endif /* DEBUG */
        struct sf_hment *sfhme;
        kmutex_t *pml, *pmtx;
        hatlock_t *hatlockp;
        int myflt;

        /*
         * remove this panic when we decide to let user virtual address
         * space be >= USERLIMIT.
         */
        if (!TTE_IS_PRIVILEGED(ttep) && vaddr >= (caddr_t)USERLIMIT)
                panic("user addr %p in kernel space", (void *)vaddr);
#if defined(TTE_IS_GLOBAL)
        if (TTE_IS_GLOBAL(ttep))
                panic("sfmmu_tteload: creating global tte");
#endif

#ifdef DEBUG
        if (pf_is_memory(sfmmu_ttetopfn(ttep, vaddr)) &&
            !TTE_IS_PCACHEABLE(ttep) && !sfmmu_allow_nc_trans)
                panic("sfmmu_tteload: non cacheable memory tte");
#endif /* DEBUG */

        /* don't simulate dirty bit for writeable ISM/DISM mappings */
        if ((flags & HAT_LOAD_SHARE) && TTE_IS_WRITABLE(ttep)) {
                TTE_SET_REF(ttep);
                TTE_SET_MOD(ttep);
        }

        if ((flags & HAT_LOAD_SHARE) || !TTE_IS_REF(ttep) ||
            !TTE_IS_MOD(ttep)) {
                /*
                 * Don't load TSB for dummy as in ISM.  Also don't preload
                 * the TSB if the TTE isn't writable since we're likely to
                 * fault on it again -- preloading can be fairly expensive.
                 */
                flags |= SFMMU_NO_TSBLOAD;
        }

        size = TTE_CSZ(ttep);
        switch (size) {
        case TTE8K:
                SFMMU_STAT(sf_tteload8k);
                break;
        case TTE64K:
                SFMMU_STAT(sf_tteload64k);
                break;
        case TTE512K:
                SFMMU_STAT(sf_tteload512k);
                break;
        case TTE4M:
                SFMMU_STAT(sf_tteload4m);
                break;
        case (TTE32M):
                SFMMU_STAT(sf_tteload32m);
                ASSERT(mmu_page_sizes == max_mmu_page_sizes);
                break;
        case (TTE256M):
                SFMMU_STAT(sf_tteload256m);
                ASSERT(mmu_page_sizes == max_mmu_page_sizes);
                break;
        }

        ASSERT(!((uintptr_t)vaddr & TTE_PAGE_OFFSET(size)));
        SFMMU_VALIDATE_HMERID(sfmmup, rid, vaddr, TTEBYTES(size));
        ASSERT(!SFMMU_IS_SHMERID_VALID(rid) || hmeblkp->hblk_shared);
        ASSERT(SFMMU_IS_SHMERID_VALID(rid) || !hmeblkp->hblk_shared);

        HBLKTOHME_IDX(sfhme, hmeblkp, vaddr, hmenum);

        /*
         * Need to grab mlist lock here so that pageunload
         * will not change tte behind us.
         */
        if (pp) {
                pml = sfmmu_mlist_enter(pp);
        }

        sfmmu_copytte(&sfhme->hme_tte, &tteold);
        /*
         * Look for corresponding hment and if valid verify
         * pfns are equal.
         */
        remap = TTE_IS_VALID(&tteold);
        if (remap) {
                pfn_t   new_pfn, old_pfn;

                old_pfn = TTE_TO_PFN(vaddr, &tteold);
                new_pfn = TTE_TO_PFN(vaddr, ttep);

                if (flags & HAT_LOAD_REMAP) {
                        /* make sure we are remapping same type of pages */
                        if (pf_is_memory(old_pfn) != pf_is_memory(new_pfn)) {
                                panic("sfmmu_tteload - tte remap io<->memory");
                        }
                        if (old_pfn != new_pfn &&
                            (pp != NULL || sfhme->hme_page != NULL)) {
                                panic("sfmmu_tteload - tte remap pp != NULL");
                        }
                } else if (old_pfn != new_pfn) {
                        panic("sfmmu_tteload - tte remap, hmeblkp 0x%p",
                            (void *)hmeblkp);
                }
                ASSERT(TTE_CSZ(&tteold) == TTE_CSZ(ttep));
        }

        if (pp) {
                if (size == TTE8K) {
#ifdef VAC
                        /*
                         * Handle VAC consistency
                         */
                        if (!remap && (cache & CACHE_VAC) && !PP_ISNC(pp)) {
                                sfmmu_vac_conflict(sfmmup, vaddr, pp);
                        }
#endif

                        if (TTE_IS_WRITABLE(ttep) && PP_ISRO(pp)) {
                                pmtx = sfmmu_page_enter(pp);
                                PP_CLRRO(pp);
                                sfmmu_page_exit(pmtx);
                        } else if (!PP_ISMAPPED(pp) &&
                            (!TTE_IS_WRITABLE(ttep)) && !(PP_ISMOD(pp))) {
                                pmtx = sfmmu_page_enter(pp);
                                if (!(PP_ISMOD(pp))) {
                                        PP_SETRO(pp);
                                }
                                sfmmu_page_exit(pmtx);
                        }

                } else if (sfmmu_pagearray_setup(vaddr, pps, ttep, remap)) {
                        /*
                         * sfmmu_pagearray_setup failed so return
                         */
                        sfmmu_mlist_exit(pml);
                        return (1);
                }
        }

        /*
         * Make sure hment is not on a mapping list.
         */
        ASSERT(remap || (sfhme->hme_page == NULL));

        /* if it is not a remap then hme->next better be NULL */
        ASSERT((!remap) ? sfhme->hme_next == NULL : 1);

        if (flags & HAT_LOAD_LOCK) {
                if ((hmeblkp->hblk_lckcnt + 1) >= MAX_HBLK_LCKCNT) {
                        panic("too high lckcnt-hmeblk %p",
                            (void *)hmeblkp);
                }
                atomic_inc_32(&hmeblkp->hblk_lckcnt);

                HBLK_STACK_TRACE(hmeblkp, HBLK_LOCK);
        }

#ifdef VAC
        if (pp && PP_ISNC(pp)) {
                /*
                 * If the physical page is marked to be uncacheable, like
                 * by a vac conflict, make sure the new mapping is also
                 * uncacheable.
                 */
                TTE_CLR_VCACHEABLE(ttep);
                ASSERT(PP_GET_VCOLOR(pp) == NO_VCOLOR);
        }
#endif
        ttep->tte_hmenum = hmenum;

#ifdef DEBUG
        orig_old = tteold;
#endif /* DEBUG */

        while (sfmmu_modifytte_try(&tteold, ttep, &sfhme->hme_tte) < 0) {
                if ((sfmmup == KHATID) &&
                    (flags & (HAT_LOAD_LOCK | HAT_LOAD_REMAP))) {
                        sfmmu_copytte(&sfhme->hme_tte, &tteold);
                }
#ifdef DEBUG
                chk_tte(&orig_old, &tteold, ttep, hmeblkp);
#endif /* DEBUG */
        }
        ASSERT(TTE_IS_VALID(&sfhme->hme_tte));

        if (!TTE_IS_VALID(&tteold)) {

                atomic_inc_16(&hmeblkp->hblk_vcnt);
                if (rid == SFMMU_INVALID_SHMERID) {
                        atomic_inc_ulong(&sfmmup->sfmmu_ttecnt[size]);
                } else {
                        sf_srd_t *srdp = sfmmup->sfmmu_srdp;
                        sf_region_t *rgnp = srdp->srd_hmergnp[rid];
                        /*
                         * We already accounted for region ttecnt's in sfmmu
                         * during hat_join_region() processing. Here we
                         * only update ttecnt's in region struture.
                         */
                        atomic_inc_ulong(&rgnp->rgn_ttecnt[size]);
                }
        }

        myflt = (astosfmmu(curthread->t_procp->p_as) == sfmmup);
        if (size > TTE8K && (flags & HAT_LOAD_SHARE) == 0 &&
            sfmmup != ksfmmup) {
                uchar_t tteflag = 1 << size;
                if (rid == SFMMU_INVALID_SHMERID) {
                        if (!(sfmmup->sfmmu_tteflags & tteflag)) {
                                hatlockp = sfmmu_hat_enter(sfmmup);
                                sfmmup->sfmmu_tteflags |= tteflag;
                                sfmmu_hat_exit(hatlockp);
                        }
                } else if (!(sfmmup->sfmmu_rtteflags & tteflag)) {
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        sfmmup->sfmmu_rtteflags |= tteflag;
                        sfmmu_hat_exit(hatlockp);
                }
                /*
                 * Update the current CPU tsbmiss area, so the current thread
                 * won't need to take the tsbmiss for the new pagesize.
                 * The other threads in the process will update their tsb
                 * miss area lazily in sfmmu_tsbmiss_exception() when they
                 * fail to find the translation for a newly added pagesize.
                 */
                if (size > TTE64K && myflt) {
                        struct tsbmiss *tsbmp;
                        kpreempt_disable();
                        tsbmp = &tsbmiss_area[CPU->cpu_id];
                        if (rid == SFMMU_INVALID_SHMERID) {
                                if (!(tsbmp->uhat_tteflags & tteflag)) {
                                        tsbmp->uhat_tteflags |= tteflag;
                                }
                        } else {
                                if (!(tsbmp->uhat_rtteflags & tteflag)) {
                                        tsbmp->uhat_rtteflags |= tteflag;
                                }
                        }
                        kpreempt_enable();
                }
        }

        if (size >= TTE4M && (flags & HAT_LOAD_TEXT) &&
            !SFMMU_FLAGS_ISSET(sfmmup, HAT_4MTEXT_FLAG)) {
                hatlockp = sfmmu_hat_enter(sfmmup);
                SFMMU_FLAGS_SET(sfmmup, HAT_4MTEXT_FLAG);
                sfmmu_hat_exit(hatlockp);
        }

        flush_tte.tte_intlo = (tteold.tte_intlo ^ ttep->tte_intlo) &
            hw_tte.tte_intlo;
        flush_tte.tte_inthi = (tteold.tte_inthi ^ ttep->tte_inthi) &
            hw_tte.tte_inthi;

        if (remap && (flush_tte.tte_inthi || flush_tte.tte_intlo)) {
                /*
                 * If remap and new tte differs from old tte we need
                 * to sync the mod bit and flush TLB/TSB.  We don't
                 * need to sync ref bit because we currently always set
                 * ref bit in tteload.
                 */
                ASSERT(TTE_IS_REF(ttep));
                if (TTE_IS_MOD(&tteold)) {
                        sfmmu_ttesync(sfmmup, vaddr, &tteold, pp);
                }
                /*
                 * hwtte bits shouldn't change for SRD hmeblks as long as SRD
                 * hmes are only used for read only text. Adding this code for
                 * completeness and future use of shared hmeblks with writable
                 * mappings of VMODSORT vnodes.
                 */
                if (hmeblkp->hblk_shared) {
                        cpuset_t cpuset = sfmmu_rgntlb_demap(vaddr,
                            sfmmup->sfmmu_srdp->srd_hmergnp[rid], hmeblkp, 1);
                        xt_sync(cpuset);
                        SFMMU_STAT_ADD(sf_region_remap_demap, 1);
                } else {
                        sfmmu_tlb_demap(vaddr, sfmmup, hmeblkp, 0, 0);
                        xt_sync(sfmmup->sfmmu_cpusran);
                }
        }

        if ((flags & SFMMU_NO_TSBLOAD) == 0) {
                /*
                 * We only preload 8K and 4M mappings into the TSB, since
                 * 64K and 512K mappings are replicated and hence don't
                 * have a single, unique TSB entry. Ditto for 32M/256M.
                 */
                if (size == TTE8K || size == TTE4M) {
                        sf_scd_t *scdp;
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        /*
                         * Don't preload private TSB if the mapping is used
                         * by the shctx in the SCD.
                         */
                        scdp = sfmmup->sfmmu_scdp;
                        if (rid == SFMMU_INVALID_SHMERID || scdp == NULL ||
                            !SF_RGNMAP_TEST(scdp->scd_hmeregion_map, rid)) {
                                sfmmu_load_tsb(sfmmup, vaddr, &sfhme->hme_tte,
                                    size);
                        }
                        sfmmu_hat_exit(hatlockp);
                }
        }
        if (pp) {
                if (!remap) {
                        HME_ADD(sfhme, pp);
                        atomic_inc_16(&hmeblkp->hblk_hmecnt);
                        ASSERT(hmeblkp->hblk_hmecnt > 0);

                        /*
                         * Cannot ASSERT(hmeblkp->hblk_hmecnt <= NHMENTS)
                         * see pageunload() for comment.
                         */
                }
                sfmmu_mlist_exit(pml);
        }

        return (0);
}
/*
 * Function unlocks hash bucket.
 */
static void
sfmmu_tteload_release_hashbucket(struct hmehash_bucket *hmebp)
{
        ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));
        SFMMU_HASH_UNLOCK(hmebp);
}

/*
 * function which checks and sets up page array for a large
 * translation.  Will set p_vcolor, p_index, p_ro fields.
 * Assumes addr and pfnum of first page are properly aligned.
 * Will check for physical contiguity. If check fails it return
 * non null.
 */
static int
sfmmu_pagearray_setup(caddr_t addr, page_t **pps, tte_t *ttep, int remap)
{
        int     i, index, ttesz;
        pfn_t   pfnum;
        pgcnt_t npgs;
        page_t *pp, *pp1;
        kmutex_t *pmtx;
#ifdef VAC
        int osz;
        int cflags = 0;
        int vac_err = 0;
#endif
        int newidx = 0;

        ttesz = TTE_CSZ(ttep);

        ASSERT(ttesz > TTE8K);

        npgs = TTEPAGES(ttesz);
        index = PAGESZ_TO_INDEX(ttesz);

        pfnum = (*pps)->p_pagenum;
        ASSERT(IS_P2ALIGNED(pfnum, npgs));

        /*
         * Save the first pp so we can do HAT_TMPNC at the end.
         */
        pp1 = *pps;
#ifdef VAC
        osz = fnd_mapping_sz(pp1);
#endif

        for (i = 0; i < npgs; i++, pps++) {
                pp = *pps;
                ASSERT(PAGE_LOCKED(pp));
                ASSERT(pp->p_szc >= ttesz);
                ASSERT(pp->p_szc == pp1->p_szc);
                ASSERT(sfmmu_mlist_held(pp));

                /*
                 * XXX is it possible to maintain P_RO on the root only?
                 */
                if (TTE_IS_WRITABLE(ttep) && PP_ISRO(pp)) {
                        pmtx = sfmmu_page_enter(pp);
                        PP_CLRRO(pp);
                        sfmmu_page_exit(pmtx);
                } else if (!PP_ISMAPPED(pp) && !TTE_IS_WRITABLE(ttep) &&
                    !PP_ISMOD(pp)) {
                        pmtx = sfmmu_page_enter(pp);
                        if (!(PP_ISMOD(pp))) {
                                PP_SETRO(pp);
                        }
                        sfmmu_page_exit(pmtx);
                }

                /*
                 * If this is a remap we skip vac & contiguity checks.
                 */
                if (remap)
                        continue;

                /*
                 * set p_vcolor and detect any vac conflicts.
                 */
#ifdef VAC
                if (vac_err == 0) {
                        vac_err = sfmmu_vacconflict_array(addr, pp, &cflags);

                }
#endif

                /*
                 * Save current index in case we need to undo it.
                 * Note: "PAGESZ_TO_INDEX(sz)   (1 << (sz))"
                 *      "SFMMU_INDEX_SHIFT      6"
                 *       "SFMMU_INDEX_MASK      ((1 << SFMMU_INDEX_SHIFT) - 1)"
                 *       "PP_MAPINDEX(p_index)  (p_index & SFMMU_INDEX_MASK)"
                 *
                 * So:  index = PAGESZ_TO_INDEX(ttesz);
                 *      if ttesz == 1 then index = 0x2
                 *                  2 then index = 0x4
                 *                  3 then index = 0x8
                 *                  4 then index = 0x10
                 *                  5 then index = 0x20
                 * The code below checks if it's a new pagesize (ie, newidx)
                 * in case we need to take it back out of p_index,
                 * and then or's the new index into the existing index.
                 */
                if ((PP_MAPINDEX(pp) & index) == 0)
                        newidx = 1;
                pp->p_index = (PP_MAPINDEX(pp) | index);

                /*
                 * contiguity check
                 */
                if (pp->p_pagenum != pfnum) {
                        /*
                         * If we fail the contiguity test then
                         * the only thing we need to fix is the p_index field.
                         * We might get a few extra flushes but since this
                         * path is rare that is ok.  The p_ro field will
                         * get automatically fixed on the next tteload to
                         * the page.  NO TNC bit is set yet.
                         */
                        while (i >= 0) {
                                pp = *pps;
                                if (newidx)
                                        pp->p_index = (PP_MAPINDEX(pp) &
                                            ~index);
                                pps--;
                                i--;
                        }
                        return (1);
                }
                pfnum++;
                addr += MMU_PAGESIZE;
        }

#ifdef VAC
        if (vac_err) {
                if (ttesz > osz) {
                        /*
                         * There are some smaller mappings that causes vac
                         * conflicts. Convert all existing small mappings to
                         * TNC.
                         */
                        SFMMU_STAT_ADD(sf_uncache_conflict, npgs);
                        sfmmu_page_cache_array(pp1, HAT_TMPNC, CACHE_FLUSH,
                            npgs);
                } else {
                        /* EMPTY */
                        /*
                         * If there exists an big page mapping,
                         * that means the whole existing big page
                         * has TNC setting already. No need to covert to
                         * TNC again.
                         */
                        ASSERT(PP_ISTNC(pp1));
                }
        }
#endif  /* VAC */

        return (0);
}

#ifdef VAC
/*
 * Routine that detects vac consistency for a large page. It also
 * sets virtual color for all pp's for this big mapping.
 */
static int
sfmmu_vacconflict_array(caddr_t addr, page_t *pp, int *cflags)
{
        int vcolor, ocolor;

        ASSERT(sfmmu_mlist_held(pp));

        if (PP_ISNC(pp)) {
                return (HAT_TMPNC);
        }

        vcolor = addr_to_vcolor(addr);
        if (PP_NEWPAGE(pp)) {
                PP_SET_VCOLOR(pp, vcolor);
                return (0);
        }

        ocolor = PP_GET_VCOLOR(pp);
        if (ocolor == vcolor) {
                return (0);
        }

        if (!PP_ISMAPPED(pp) && !PP_ISMAPPED_KPM(pp)) {
                /*
                 * Previous user of page had a differnet color
                 * but since there are no current users
                 * we just flush the cache and change the color.
                 * As an optimization for large pages we flush the
                 * entire cache of that color and set a flag.
                 */
                SFMMU_STAT(sf_pgcolor_conflict);
                if (!CacheColor_IsFlushed(*cflags, ocolor)) {
                        CacheColor_SetFlushed(*cflags, ocolor);
                        sfmmu_cache_flushcolor(ocolor, pp->p_pagenum);
                }
                PP_SET_VCOLOR(pp, vcolor);
                return (0);
        }

        /*
         * We got a real conflict with a current mapping.
         * set flags to start unencaching all mappings
         * and return failure so we restart looping
         * the pp array from the beginning.
         */
        return (HAT_TMPNC);
}
#endif  /* VAC */

/*
 * creates a large page shadow hmeblk for a tte.
 * The purpose of this routine is to allow us to do quick unloads because
 * the vm layer can easily pass a very large but sparsely populated range.
 */
static struct hme_blk *
sfmmu_shadow_hcreate(sfmmu_t *sfmmup, caddr_t vaddr, int ttesz, uint_t flags)
{
        struct hmehash_bucket *hmebp;
        hmeblk_tag hblktag;
        int hmeshift, size, vshift;
        uint_t shw_mask, newshw_mask;
        struct hme_blk *hmeblkp;

        ASSERT(sfmmup != KHATID);
        if (mmu_page_sizes == max_mmu_page_sizes) {
                ASSERT(ttesz < TTE256M);
        } else {
                ASSERT(ttesz < TTE4M);
                ASSERT(sfmmup->sfmmu_ttecnt[TTE32M] == 0);
                ASSERT(sfmmup->sfmmu_ttecnt[TTE256M] == 0);
        }

        if (ttesz == TTE8K) {
                size = TTE512K;
        } else {
                size = ++ttesz;
        }

        hblktag.htag_id = sfmmup;
        hmeshift = HME_HASH_SHIFT(size);
        hblktag.htag_bspage = HME_HASH_BSPAGE(vaddr, hmeshift);
        hblktag.htag_rehash = HME_HASH_REHASH(size);
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;
        hmebp = HME_HASH_FUNCTION(sfmmup, vaddr, hmeshift);

        SFMMU_HASH_LOCK(hmebp);

        HME_HASH_FAST_SEARCH(hmebp, hblktag, hmeblkp);
        ASSERT(hmeblkp != (struct hme_blk *)hblk_reserve);
        if (hmeblkp == NULL) {
                hmeblkp = sfmmu_hblk_alloc(sfmmup, vaddr, hmebp, size,
                    hblktag, flags, SFMMU_INVALID_SHMERID);
        }
        ASSERT(hmeblkp);
        if (!hmeblkp->hblk_shw_mask) {
                /*
                 * if this is a unused hblk it was just allocated or could
                 * potentially be a previous large page hblk so we need to
                 * set the shadow bit.
                 */
                ASSERT(!hmeblkp->hblk_vcnt && !hmeblkp->hblk_hmecnt);
                hmeblkp->hblk_shw_bit = 1;
        } else if (hmeblkp->hblk_shw_bit == 0) {
                panic("sfmmu_shadow_hcreate: shw bit not set in hmeblkp 0x%p",
                    (void *)hmeblkp);
        }
        ASSERT(hmeblkp->hblk_shw_bit == 1);
        ASSERT(!hmeblkp->hblk_shared);
        vshift = vaddr_to_vshift(hblktag, vaddr, size);
        ASSERT(vshift < 8);
        /*
         * Atomically set shw mask bit
         */
        do {
                shw_mask = hmeblkp->hblk_shw_mask;
                newshw_mask = shw_mask | (1 << vshift);
                newshw_mask = atomic_cas_32(&hmeblkp->hblk_shw_mask, shw_mask,
                    newshw_mask);
        } while (newshw_mask != shw_mask);

        SFMMU_HASH_UNLOCK(hmebp);

        return (hmeblkp);
}

/*
 * This routine cleanup a previous shadow hmeblk and changes it to
 * a regular hblk.  This happens rarely but it is possible
 * when a process wants to use large pages and there are hblks still
 * lying around from the previous as that used these hmeblks.
 * The alternative was to cleanup the shadow hblks at unload time
 * but since so few user processes actually use large pages, it is
 * better to be lazy and cleanup at this time.
 */
static void
sfmmu_shadow_hcleanup(sfmmu_t *sfmmup, struct hme_blk *hmeblkp,
    struct hmehash_bucket *hmebp)
{
        caddr_t addr, endaddr;
        int hashno, size;

        ASSERT(hmeblkp->hblk_shw_bit);
        ASSERT(!hmeblkp->hblk_shared);

        ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));

        if (!hmeblkp->hblk_shw_mask) {
                hmeblkp->hblk_shw_bit = 0;
                return;
        }
        addr = (caddr_t)get_hblk_base(hmeblkp);
        endaddr = get_hblk_endaddr(hmeblkp);
        size = get_hblk_ttesz(hmeblkp);
        hashno = size - 1;
        ASSERT(hashno > 0);
        SFMMU_HASH_UNLOCK(hmebp);

        sfmmu_free_hblks(sfmmup, addr, endaddr, hashno);

        SFMMU_HASH_LOCK(hmebp);
}

static void
sfmmu_free_hblks(sfmmu_t *sfmmup, caddr_t addr, caddr_t endaddr,
    int hashno)
{
        int hmeshift, shadow = 0;
        hmeblk_tag hblktag;
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        struct hme_blk *nx_hblk, *pr_hblk, *list = NULL;

        ASSERT(hashno > 0);
        hblktag.htag_id = sfmmup;
        hblktag.htag_rehash = hashno;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;

        hmeshift = HME_HASH_SHIFT(hashno);

        while (addr < endaddr) {
                hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
                hmebp = HME_HASH_FUNCTION(sfmmup, addr, hmeshift);
                SFMMU_HASH_LOCK(hmebp);
                /* inline HME_HASH_SEARCH */
                hmeblkp = hmebp->hmeblkp;
                pr_hblk = NULL;
                while (hmeblkp) {
                        if (HTAGS_EQ(hmeblkp->hblk_tag, hblktag)) {
                                /* found hme_blk */
                                ASSERT(!hmeblkp->hblk_shared);
                                if (hmeblkp->hblk_shw_bit) {
                                        if (hmeblkp->hblk_shw_mask) {
                                                shadow = 1;
                                                sfmmu_shadow_hcleanup(sfmmup,
                                                    hmeblkp, hmebp);
                                                break;
                                        } else {
                                                hmeblkp->hblk_shw_bit = 0;
                                        }
                                }

                                /*
                                 * Hblk_hmecnt and hblk_vcnt could be non zero
                                 * since hblk_unload() does not gurantee that.
                                 *
                                 * XXX - this could cause tteload() to spin
                                 * where sfmmu_shadow_hcleanup() is called.
                                 */
                        }

                        nx_hblk = hmeblkp->hblk_next;
                        if (!hmeblkp->hblk_vcnt && !hmeblkp->hblk_hmecnt) {
                                sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk,
                                    &list, 0);
                        } else {
                                pr_hblk = hmeblkp;
                        }
                        hmeblkp = nx_hblk;
                }

                SFMMU_HASH_UNLOCK(hmebp);

                if (shadow) {
                        /*
                         * We found another shadow hblk so cleaned its
                         * children.  We need to go back and cleanup
                         * the original hblk so we don't change the
                         * addr.
                         */
                        shadow = 0;
                } else {
                        addr = (caddr_t)roundup((uintptr_t)addr + 1,
                            (1 << hmeshift));
                }
        }
        sfmmu_hblks_list_purge(&list, 0);
}

/*
 * This routine's job is to delete stale invalid shared hmeregions hmeblks that
 * may still linger on after pageunload.
 */
static void
sfmmu_cleanup_rhblk(sf_srd_t *srdp, caddr_t addr, uint_t rid, int ttesz)
{
        int hmeshift;
        hmeblk_tag hblktag;
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        struct hme_blk *pr_hblk;
        struct hme_blk *list = NULL;

        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
        ASSERT(rid < SFMMU_MAX_HME_REGIONS);

        hmeshift = HME_HASH_SHIFT(ttesz);
        hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
        hblktag.htag_rehash = ttesz;
        hblktag.htag_rid = rid;
        hblktag.htag_id = srdp;
        hmebp = HME_HASH_FUNCTION(srdp, addr, hmeshift);

        SFMMU_HASH_LOCK(hmebp);
        HME_HASH_SEARCH_PREV(hmebp, hblktag, hmeblkp, pr_hblk, &list);
        if (hmeblkp != NULL) {
                ASSERT(hmeblkp->hblk_shared);
                ASSERT(!hmeblkp->hblk_shw_bit);
                if (hmeblkp->hblk_vcnt || hmeblkp->hblk_hmecnt) {
                        panic("sfmmu_cleanup_rhblk: valid hmeblk");
                }
                ASSERT(!hmeblkp->hblk_lckcnt);
                sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk,
                    &list, 0);
        }
        SFMMU_HASH_UNLOCK(hmebp);
        sfmmu_hblks_list_purge(&list, 0);
}

/* ARGSUSED */
static void
sfmmu_rgn_cb_noop(caddr_t saddr, caddr_t eaddr, caddr_t r_saddr,
    size_t r_size, void *r_obj, u_offset_t r_objoff)
{
}

/*
 * Searches for an hmeblk which maps addr, then unloads this mapping
 * and updates *eaddrp, if the hmeblk is found.
 */
static void
sfmmu_unload_hmeregion_va(sf_srd_t *srdp, uint_t rid, caddr_t addr,
    caddr_t eaddr, int ttesz, caddr_t *eaddrp)
{
        int hmeshift;
        hmeblk_tag hblktag;
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        struct hme_blk *pr_hblk;
        struct hme_blk *list = NULL;

        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
        ASSERT(ttesz >= HBLK_MIN_TTESZ);

        hmeshift = HME_HASH_SHIFT(ttesz);
        hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
        hblktag.htag_rehash = ttesz;
        hblktag.htag_rid = rid;
        hblktag.htag_id = srdp;
        hmebp = HME_HASH_FUNCTION(srdp, addr, hmeshift);

        SFMMU_HASH_LOCK(hmebp);
        HME_HASH_SEARCH_PREV(hmebp, hblktag, hmeblkp, pr_hblk, &list);
        if (hmeblkp != NULL) {
                ASSERT(hmeblkp->hblk_shared);
                ASSERT(!hmeblkp->hblk_lckcnt);
                if (hmeblkp->hblk_vcnt || hmeblkp->hblk_hmecnt) {
                        *eaddrp = sfmmu_hblk_unload(NULL, hmeblkp, addr,
                            eaddr, NULL, HAT_UNLOAD);
                        ASSERT(*eaddrp > addr);
                }
                ASSERT(!hmeblkp->hblk_vcnt && !hmeblkp->hblk_hmecnt);
                sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk,
                    &list, 0);
        }
        SFMMU_HASH_UNLOCK(hmebp);
        sfmmu_hblks_list_purge(&list, 0);
}

static void
sfmmu_unload_hmeregion(sf_srd_t *srdp, sf_region_t *rgnp)
{
        int ttesz = rgnp->rgn_pgszc;
        size_t rsz = rgnp->rgn_size;
        caddr_t rsaddr = rgnp->rgn_saddr;
        caddr_t readdr = rsaddr + rsz;
        caddr_t rhsaddr;
        caddr_t va;
        uint_t rid = rgnp->rgn_id;
        caddr_t cbsaddr;
        caddr_t cbeaddr;
        hat_rgn_cb_func_t rcbfunc;
        ulong_t cnt;

        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
        ASSERT(rid < SFMMU_MAX_HME_REGIONS);

        ASSERT(IS_P2ALIGNED(rsaddr, TTEBYTES(ttesz)));
        ASSERT(IS_P2ALIGNED(rsz, TTEBYTES(ttesz)));
        if (ttesz < HBLK_MIN_TTESZ) {
                ttesz = HBLK_MIN_TTESZ;
                rhsaddr = (caddr_t)P2ALIGN((uintptr_t)rsaddr, HBLK_MIN_BYTES);
        } else {
                rhsaddr = rsaddr;
        }

        if ((rcbfunc = rgnp->rgn_cb_function) == NULL) {
                rcbfunc = sfmmu_rgn_cb_noop;
        }

        while (ttesz >= HBLK_MIN_TTESZ) {
                cbsaddr = rsaddr;
                cbeaddr = rsaddr;
                if (!(rgnp->rgn_hmeflags & (1 << ttesz))) {
                        ttesz--;
                        continue;
                }
                cnt = 0;
                va = rsaddr;
                while (va < readdr) {
                        ASSERT(va >= rhsaddr);
                        if (va != cbeaddr) {
                                if (cbeaddr != cbsaddr) {
                                        ASSERT(cbeaddr > cbsaddr);
                                        (*rcbfunc)(cbsaddr, cbeaddr,
                                            rsaddr, rsz, rgnp->rgn_obj,
                                            rgnp->rgn_objoff);
                                }
                                cbsaddr = va;
                                cbeaddr = va;
                        }
                        sfmmu_unload_hmeregion_va(srdp, rid, va, readdr,
                            ttesz, &cbeaddr);
                        cnt++;
                        va = rhsaddr + (cnt << TTE_PAGE_SHIFT(ttesz));
                }
                if (cbeaddr != cbsaddr) {
                        ASSERT(cbeaddr > cbsaddr);
                        (*rcbfunc)(cbsaddr, cbeaddr, rsaddr,
                            rsz, rgnp->rgn_obj,
                            rgnp->rgn_objoff);
                }
                ttesz--;
        }
}

/*
 * Release one hardware address translation lock on the given address range.
 */
void
hat_unlock(struct hat *sfmmup, caddr_t addr, size_t len)
{
        struct hmehash_bucket *hmebp;
        hmeblk_tag hblktag;
        int hmeshift, hashno = 1;
        struct hme_blk *hmeblkp, *list = NULL;
        caddr_t endaddr;

        ASSERT(sfmmup != NULL);

        ASSERT((sfmmup == ksfmmup) || AS_LOCK_HELD(sfmmup->sfmmu_as));
        ASSERT((len & MMU_PAGEOFFSET) == 0);
        endaddr = addr + len;
        hblktag.htag_id = sfmmup;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;

        /*
         * Spitfire supports 4 page sizes.
         * Most pages are expected to be of the smallest page size (8K) and
         * these will not need to be rehashed. 64K pages also don't need to be
         * rehashed because an hmeblk spans 64K of address space. 512K pages
         * might need 1 rehash and and 4M pages might need 2 rehashes.
         */
        while (addr < endaddr) {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(sfmmup, addr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_SEARCH(hmebp, hblktag, hmeblkp, &list);
                if (hmeblkp != NULL) {
                        ASSERT(!hmeblkp->hblk_shared);
                        /*
                         * If we encounter a shadow hmeblk then
                         * we know there are no valid hmeblks mapping
                         * this address at this size or larger.
                         * Just increment address by the smallest
                         * page size.
                         */
                        if (hmeblkp->hblk_shw_bit) {
                                addr += MMU_PAGESIZE;
                        } else {
                                addr = sfmmu_hblk_unlock(hmeblkp, addr,
                                    endaddr);
                        }
                        SFMMU_HASH_UNLOCK(hmebp);
                        hashno = 1;
                        continue;
                }
                SFMMU_HASH_UNLOCK(hmebp);

                if (!HME_REHASH(sfmmup) || (hashno >= mmu_hashcnt)) {
                        /*
                         * We have traversed the whole list and rehashed
                         * if necessary without finding the address to unlock
                         * which should never happen.
                         */
                        panic("sfmmu_unlock: addr not found. "
                            "addr %p hat %p", (void *)addr, (void *)sfmmup);
                } else {
                        hashno++;
                }
        }

        sfmmu_hblks_list_purge(&list, 0);
}

void
hat_unlock_region(struct hat *sfmmup, caddr_t addr, size_t len,
    hat_region_cookie_t rcookie)
{
        sf_srd_t *srdp;
        sf_region_t *rgnp;
        int ttesz;
        uint_t rid;
        caddr_t eaddr;
        caddr_t va;
        int hmeshift;
        hmeblk_tag hblktag;
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        struct hme_blk *pr_hblk;
        struct hme_blk *list;

        if (rcookie == HAT_INVALID_REGION_COOKIE) {
                hat_unlock(sfmmup, addr, len);
                return;
        }

        ASSERT(sfmmup != NULL);
        ASSERT(sfmmup != ksfmmup);

        srdp = sfmmup->sfmmu_srdp;
        rid = (uint_t)((uint64_t)rcookie);
        VERIFY3U(rid, <, SFMMU_MAX_HME_REGIONS);
        eaddr = addr + len;
        va = addr;
        list = NULL;
        rgnp = srdp->srd_hmergnp[rid];
        SFMMU_VALIDATE_HMERID(sfmmup, rid, addr, len);

        ASSERT(IS_P2ALIGNED(addr, TTEBYTES(rgnp->rgn_pgszc)));
        ASSERT(IS_P2ALIGNED(len, TTEBYTES(rgnp->rgn_pgszc)));
        if (rgnp->rgn_pgszc < HBLK_MIN_TTESZ) {
                ttesz = HBLK_MIN_TTESZ;
        } else {
                ttesz = rgnp->rgn_pgszc;
        }
        while (va < eaddr) {
                while (ttesz < rgnp->rgn_pgszc &&
                    IS_P2ALIGNED(va, TTEBYTES(ttesz + 1))) {
                        ttesz++;
                }
                while (ttesz >= HBLK_MIN_TTESZ) {
                        if (!(rgnp->rgn_hmeflags & (1 << ttesz))) {
                                ttesz--;
                                continue;
                        }
                        hmeshift = HME_HASH_SHIFT(ttesz);
                        hblktag.htag_bspage = HME_HASH_BSPAGE(va, hmeshift);
                        hblktag.htag_rehash = ttesz;
                        hblktag.htag_rid = rid;
                        hblktag.htag_id = srdp;
                        hmebp = HME_HASH_FUNCTION(srdp, va, hmeshift);
                        SFMMU_HASH_LOCK(hmebp);
                        HME_HASH_SEARCH_PREV(hmebp, hblktag, hmeblkp, pr_hblk,
                            &list);
                        if (hmeblkp == NULL) {
                                SFMMU_HASH_UNLOCK(hmebp);
                                ttesz--;
                                continue;
                        }
                        ASSERT(hmeblkp->hblk_shared);
                        va = sfmmu_hblk_unlock(hmeblkp, va, eaddr);
                        ASSERT(va >= eaddr ||
                            IS_P2ALIGNED((uintptr_t)va, TTEBYTES(ttesz)));
                        SFMMU_HASH_UNLOCK(hmebp);
                        break;
                }
                if (ttesz < HBLK_MIN_TTESZ) {
                        panic("hat_unlock_region: addr not found "
                            "addr %p hat %p", (void *)va, (void *)sfmmup);
                }
        }
        sfmmu_hblks_list_purge(&list, 0);
}

/*
 * Function to unlock a range of addresses in an hmeblk.  It returns the
 * next address that needs to be unlocked.
 * Should be called with the hash lock held.
 */
static caddr_t
sfmmu_hblk_unlock(struct hme_blk *hmeblkp, caddr_t addr, caddr_t endaddr)
{
        struct sf_hment *sfhme;
        tte_t tteold, ttemod;
        int ttesz, ret;

        ASSERT(in_hblk_range(hmeblkp, addr));
        ASSERT(hmeblkp->hblk_shw_bit == 0);

        endaddr = MIN(endaddr, get_hblk_endaddr(hmeblkp));
        ttesz = get_hblk_ttesz(hmeblkp);

        HBLKTOHME(sfhme, hmeblkp, addr);
        while (addr < endaddr) {
readtte:
                sfmmu_copytte(&sfhme->hme_tte, &tteold);
                if (TTE_IS_VALID(&tteold)) {

                        ttemod = tteold;

                        ret = sfmmu_modifytte_try(&tteold, &ttemod,
                            &sfhme->hme_tte);

                        if (ret < 0)
                                goto readtte;

                        if (hmeblkp->hblk_lckcnt == 0)
                                panic("zero hblk lckcnt");

                        if (((uintptr_t)addr + TTEBYTES(ttesz)) >
                            (uintptr_t)endaddr)
                                panic("can't unlock large tte");

                        ASSERT(hmeblkp->hblk_lckcnt > 0);
                        atomic_dec_32(&hmeblkp->hblk_lckcnt);
                        HBLK_STACK_TRACE(hmeblkp, HBLK_UNLOCK);
                } else {
                        panic("sfmmu_hblk_unlock: invalid tte");
                }
                addr += TTEBYTES(ttesz);
                sfhme++;
        }
        return (addr);
}

/*
 * Physical Address Mapping Framework
 *
 * General rules:
 *
 * (1) Applies only to seg_kmem memory pages. To make things easier,
 *     seg_kpm addresses are also accepted by the routines, but nothing
 *     is done with them since by definition their PA mappings are static.
 * (2) hat_add_callback() may only be called while holding the page lock
 *     SE_SHARED or SE_EXCL of the underlying page (e.g., as_pagelock()),
 *     or passing HAC_PAGELOCK flag.
 * (3) prehandler() and posthandler() may not call hat_add_callback() or
 *     hat_delete_callback(), nor should they allocate memory. Post quiesce
 *     callbacks may not sleep or acquire adaptive mutex locks.
 * (4) Either prehandler() or posthandler() (but not both) may be specified
 *     as being NULL.  Specifying an errhandler() is optional.
 *
 * Details of using the framework:
 *
 * registering a callback (hat_register_callback())
 *
 *      Pass prehandler, posthandler, errhandler addresses
 *      as described below. If capture_cpus argument is nonzero,
 *      suspend callback to the prehandler will occur with CPUs
 *      captured and executing xc_loop() and CPUs will remain
 *      captured until after the posthandler suspend callback
 *      occurs.
 *
 * adding a callback (hat_add_callback())
 *
 *      as_pagelock();
 *      hat_add_callback();
 *      save returned pfn in private data structures or program registers;
 *      as_pageunlock();
 *
 * prehandler()
 *
 *      Stop all accesses by physical address to this memory page.
 *      Called twice: the first, PRESUSPEND, is a context safe to acquire
 *      adaptive locks. The second, SUSPEND, is called at high PIL with
 *      CPUs captured so adaptive locks may NOT be acquired (and all spin
 *      locks must be XCALL_PIL or higher locks).
 *
 *      May return the following errors:
 *              EIO:    A fatal error has occurred. This will result in panic.
 *              EAGAIN: The page cannot be suspended. This will fail the
 *                      relocation.
 *              0:      Success.
 *
 * posthandler()
 *
 *      Save new pfn in private data structures or program registers;
 *      not allowed to fail (non-zero return values will result in panic).
 *
 * errhandler()
 *
 *      called when an error occurs related to the callback.  Currently
 *      the only such error is HAT_CB_ERR_LEAKED which indicates that
 *      a page is being freed, but there are still outstanding callback(s)
 *      registered on the page.
 *
 * removing a callback (hat_delete_callback(); e.g., prior to freeing memory)
 *
 *      stop using physical address
 *      hat_delete_callback();
 *
 */

/*
 * Register a callback class.  Each subsystem should do this once and
 * cache the id_t returned for use in setting up and tearing down callbacks.
 *
 * There is no facility for removing callback IDs once they are created;
 * the "key" should be unique for each module, so in case a module is unloaded
 * and subsequently re-loaded, we can recycle the module's previous entry.
 */
id_t
hat_register_callback(int key,
    int (*prehandler)(caddr_t, uint_t, uint_t, void *),
    int (*posthandler)(caddr_t, uint_t, uint_t, void *, pfn_t),
    int (*errhandler)(caddr_t, uint_t, uint_t, void *),
    int capture_cpus)
{
        id_t id;

        /*
         * Search the table for a pre-existing callback associated with
         * the identifier "key".  If one exists, we re-use that entry in
         * the table for this instance, otherwise we assign the next
         * available table slot.
         */
        for (id = 0; id < sfmmu_max_cb_id; id++) {
                if (sfmmu_cb_table[id].key == key)
                        break;
        }

        if (id == sfmmu_max_cb_id) {
                id = sfmmu_cb_nextid++;
                if (id >= sfmmu_max_cb_id)
                        panic("hat_register_callback: out of callback IDs");
        }

        ASSERT(prehandler != NULL || posthandler != NULL);

        sfmmu_cb_table[id].key = key;
        sfmmu_cb_table[id].prehandler = prehandler;
        sfmmu_cb_table[id].posthandler = posthandler;
        sfmmu_cb_table[id].errhandler = errhandler;
        sfmmu_cb_table[id].capture_cpus = capture_cpus;

        return (id);
}

#define HAC_COOKIE_NONE (void *)-1

/*
 * Add relocation callbacks to the specified addr/len which will be called
 * when relocating the associated page. See the description of pre and
 * posthandler above for more details.
 *
 * If HAC_PAGELOCK is included in flags, the underlying memory page is
 * locked internally so the caller must be able to deal with the callback
 * running even before this function has returned.  If HAC_PAGELOCK is not
 * set, it is assumed that the underlying memory pages are locked.
 *
 * Since the caller must track the individual page boundaries anyway,
 * we only allow a callback to be added to a single page (large
 * or small).  Thus [addr, addr + len) MUST be contained within a single
 * page.
 *
 * Registering multiple callbacks on the same [addr, addr+len) is supported,
 * _provided_that_ a unique parameter is specified for each callback.
 * If multiple callbacks are registered on the same range the callback will
 * be invoked with each unique parameter. Registering the same callback with
 * the same argument more than once will result in corrupted kernel state.
 *
 * Returns the pfn of the underlying kernel page in *rpfn
 * on success, or PFN_INVALID on failure.
 *
 * cookiep (if passed) provides storage space for an opaque cookie
 * to return later to hat_delete_callback(). This cookie makes the callback
 * deletion significantly quicker by avoiding a potentially lengthy hash
 * search.
 *
 * Returns values:
 *    0:      success
 *    ENOMEM: memory allocation failure (e.g. flags was passed as HAC_NOSLEEP)
 *    EINVAL: callback ID is not valid
 *    ENXIO:  ["vaddr", "vaddr" + len) is not mapped in the kernel's address
 *            space
 *    ERANGE: ["vaddr", "vaddr" + len) crosses a page boundary
 */
int
hat_add_callback(id_t callback_id, caddr_t vaddr, uint_t len, uint_t flags,
    void *pvt, pfn_t *rpfn, void **cookiep)
{
        struct          hmehash_bucket *hmebp;
        hmeblk_tag      hblktag;
        struct hme_blk  *hmeblkp;
        int             hmeshift, hashno;
        caddr_t         saddr, eaddr, baseaddr;
        struct pa_hment *pahmep;
        struct sf_hment *sfhmep, *osfhmep;
        kmutex_t        *pml;
        tte_t           tte;
        page_t          *pp;
        vnode_t         *vp;
        u_offset_t      off;
        pfn_t           pfn;
        int             kmflags = (flags & HAC_SLEEP)? KM_SLEEP : KM_NOSLEEP;
        int             locked = 0;

        /*
         * For KPM mappings, just return the physical address since we
         * don't need to register any callbacks.
         */
        if (IS_KPM_ADDR(vaddr)) {
                uint64_t paddr;
                SFMMU_KPM_VTOP(vaddr, paddr);
                *rpfn = btop(paddr);
                if (cookiep != NULL)
                        *cookiep = HAC_COOKIE_NONE;
                return (0);
        }

        if (callback_id < (id_t)0 || callback_id >= sfmmu_cb_nextid) {
                *rpfn = PFN_INVALID;
                return (EINVAL);
        }

        if ((pahmep = kmem_cache_alloc(pa_hment_cache, kmflags)) == NULL) {
                *rpfn = PFN_INVALID;
                return (ENOMEM);
        }

        sfhmep = &pahmep->sfment;

        saddr = (caddr_t)((uintptr_t)vaddr & MMU_PAGEMASK);
        eaddr = saddr + len;

rehash:
        /* Find the mapping(s) for this page */
        for (hashno = TTE64K, hmeblkp = NULL;
            hmeblkp == NULL && hashno <= mmu_hashcnt;
            hashno++) {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_id = ksfmmup;
                hblktag.htag_rid = SFMMU_INVALID_SHMERID;
                hblktag.htag_bspage = HME_HASH_BSPAGE(saddr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(ksfmmup, saddr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_FAST_SEARCH(hmebp, hblktag, hmeblkp);

                if (hmeblkp == NULL)
                        SFMMU_HASH_UNLOCK(hmebp);
        }

        if (hmeblkp == NULL) {
                kmem_cache_free(pa_hment_cache, pahmep);
                *rpfn = PFN_INVALID;
                return (ENXIO);
        }

        ASSERT(!hmeblkp->hblk_shared);

        HBLKTOHME(osfhmep, hmeblkp, saddr);
        sfmmu_copytte(&osfhmep->hme_tte, &tte);

        if (!TTE_IS_VALID(&tte)) {
                SFMMU_HASH_UNLOCK(hmebp);
                kmem_cache_free(pa_hment_cache, pahmep);
                *rpfn = PFN_INVALID;
                return (ENXIO);
        }

        /*
         * Make sure the boundaries for the callback fall within this
         * single mapping.
         */
        baseaddr = (caddr_t)get_hblk_base(hmeblkp);
        ASSERT(saddr >= baseaddr);
        if (eaddr > saddr + TTEBYTES(TTE_CSZ(&tte))) {
                SFMMU_HASH_UNLOCK(hmebp);
                kmem_cache_free(pa_hment_cache, pahmep);
                *rpfn = PFN_INVALID;
                return (ERANGE);
        }

        pfn = sfmmu_ttetopfn(&tte, vaddr);

        /*
         * The pfn may not have a page_t underneath in which case we
         * just return it. This can happen if we are doing I/O to a
         * static portion of the kernel's address space, for instance.
         */
        pp = osfhmep->hme_page;
        if (pp == NULL) {
                SFMMU_HASH_UNLOCK(hmebp);
                kmem_cache_free(pa_hment_cache, pahmep);
                *rpfn = pfn;
                if (cookiep)
                        *cookiep = HAC_COOKIE_NONE;
                return (0);
        }
        ASSERT(pp == PP_PAGEROOT(pp));

        vp = pp->p_vnode;
        off = pp->p_offset;

        pml = sfmmu_mlist_enter(pp);

        if (flags & HAC_PAGELOCK) {
                if (!page_trylock(pp, SE_SHARED)) {
                        /*
                         * Somebody is holding SE_EXCL lock. Might even be
                         * hat_page_relocate().
                         * Drop all our locks, lookup the page in &kvp, and
                         * retry.
                         * If it doesn't exist in &kvp and &kvps[KV_ZVP],
                         * then we must be dealing with a kernel mapped
                         * page which doesn't actually belong to
                         * segkmem so we punt.
                         */
                        sfmmu_mlist_exit(pml);
                        SFMMU_HASH_UNLOCK(hmebp);
                        pp = page_lookup(&kvp, (u_offset_t)saddr, SE_SHARED);

                        /* check &kvps[KV_ZVP] before giving up */
                        if (pp == NULL)
                                pp = page_lookup(&kvps[KV_ZVP],
                                    (u_offset_t)saddr, SE_SHARED);

                        /* Okay, we didn't find it, give up */
                        if (pp == NULL) {
                                kmem_cache_free(pa_hment_cache, pahmep);
                                *rpfn = pfn;
                                if (cookiep)
                                        *cookiep = HAC_COOKIE_NONE;
                                return (0);
                        }
                        page_unlock(pp);
                        goto rehash;
                }
                locked = 1;
        }

        if (!PAGE_LOCKED(pp) && !panicstr)
                panic("hat_add_callback: page 0x%p not locked", (void *)pp);

        if (osfhmep->hme_page != pp || pp->p_vnode != vp ||
            pp->p_offset != off) {
                /*
                 * The page moved before we got our hands on it.  Drop
                 * all the locks and try again.
                 */
                ASSERT((flags & HAC_PAGELOCK) != 0);
                sfmmu_mlist_exit(pml);
                SFMMU_HASH_UNLOCK(hmebp);
                page_unlock(pp);
                locked = 0;
                goto rehash;
        }

        if (!VN_ISKAS(vp)) {
                /*
                 * This is not a segkmem page but another page which
                 * has been kernel mapped. It had better have at least
                 * a share lock on it. Return the pfn.
                 */
                sfmmu_mlist_exit(pml);
                SFMMU_HASH_UNLOCK(hmebp);
                if (locked)
                        page_unlock(pp);
                kmem_cache_free(pa_hment_cache, pahmep);
                ASSERT(PAGE_LOCKED(pp));
                *rpfn = pfn;
                if (cookiep)
                        *cookiep = HAC_COOKIE_NONE;
                return (0);
        }

        /*
         * Setup this pa_hment and link its embedded dummy sf_hment into
         * the mapping list.
         */
        pp->p_share++;
        pahmep->cb_id = callback_id;
        pahmep->addr = vaddr;
        pahmep->len = len;
        pahmep->refcnt = 1;
        pahmep->flags = 0;
        pahmep->pvt = pvt;

        sfhmep->hme_tte.ll = 0;
        sfhmep->hme_data = pahmep;
        sfhmep->hme_prev = osfhmep;
        sfhmep->hme_next = osfhmep->hme_next;

        if (osfhmep->hme_next)
                osfhmep->hme_next->hme_prev = sfhmep;

        osfhmep->hme_next = sfhmep;

        sfmmu_mlist_exit(pml);
        SFMMU_HASH_UNLOCK(hmebp);

        if (locked)
                page_unlock(pp);

        *rpfn = pfn;
        if (cookiep)
                *cookiep = (void *)pahmep;

        return (0);
}

/*
 * Remove the relocation callbacks from the specified addr/len.
 */
void
hat_delete_callback(caddr_t vaddr, uint_t len, void *pvt, uint_t flags,
    void *cookie)
{
        struct          hmehash_bucket *hmebp;
        hmeblk_tag      hblktag;
        struct hme_blk  *hmeblkp;
        int             hmeshift, hashno;
        caddr_t         saddr;
        struct pa_hment *pahmep;
        struct sf_hment *sfhmep, *osfhmep;
        kmutex_t        *pml;
        tte_t           tte;
        page_t          *pp;
        vnode_t         *vp;
        u_offset_t      off;
        int             locked = 0;

        /*
         * If the cookie is HAC_COOKIE_NONE then there is no pa_hment to
         * remove so just return.
         */
        if (cookie == HAC_COOKIE_NONE || IS_KPM_ADDR(vaddr))
                return;

        saddr = (caddr_t)((uintptr_t)vaddr & MMU_PAGEMASK);

rehash:
        /* Find the mapping(s) for this page */
        for (hashno = TTE64K, hmeblkp = NULL;
            hmeblkp == NULL && hashno <= mmu_hashcnt;
            hashno++) {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_id = ksfmmup;
                hblktag.htag_rid = SFMMU_INVALID_SHMERID;
                hblktag.htag_bspage = HME_HASH_BSPAGE(saddr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(ksfmmup, saddr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_FAST_SEARCH(hmebp, hblktag, hmeblkp);

                if (hmeblkp == NULL)
                        SFMMU_HASH_UNLOCK(hmebp);
        }

        if (hmeblkp == NULL)
                return;

        ASSERT(!hmeblkp->hblk_shared);

        HBLKTOHME(osfhmep, hmeblkp, saddr);

        sfmmu_copytte(&osfhmep->hme_tte, &tte);
        if (!TTE_IS_VALID(&tte)) {
                SFMMU_HASH_UNLOCK(hmebp);
                return;
        }

        pp = osfhmep->hme_page;
        if (pp == NULL) {
                SFMMU_HASH_UNLOCK(hmebp);
                ASSERT(cookie == NULL);
                return;
        }

        vp = pp->p_vnode;
        off = pp->p_offset;

        pml = sfmmu_mlist_enter(pp);

        if (flags & HAC_PAGELOCK) {
                if (!page_trylock(pp, SE_SHARED)) {
                        /*
                         * Somebody is holding SE_EXCL lock. Might even be
                         * hat_page_relocate().
                         * Drop all our locks, lookup the page in &kvp, and
                         * retry.
                         * If it doesn't exist in &kvp and &kvps[KV_ZVP],
                         * then we must be dealing with a kernel mapped
                         * page which doesn't actually belong to
                         * segkmem so we punt.
                         */
                        sfmmu_mlist_exit(pml);
                        SFMMU_HASH_UNLOCK(hmebp);
                        pp = page_lookup(&kvp, (u_offset_t)saddr, SE_SHARED);

                        /* check &kvps[KV_ZVP] before giving up */
                        if (pp == NULL)
                                pp = page_lookup(&kvps[KV_ZVP],
                                    (u_offset_t)saddr, SE_SHARED);

                        if (pp == NULL) {
                                ASSERT(cookie == NULL);
                                return;
                        }
                        page_unlock(pp);
                        goto rehash;
                }
                locked = 1;
        }

        ASSERT(PAGE_LOCKED(pp));

        if (osfhmep->hme_page != pp || pp->p_vnode != vp ||
            pp->p_offset != off) {
                /*
                 * The page moved before we got our hands on it.  Drop
                 * all the locks and try again.
                 */
                ASSERT((flags & HAC_PAGELOCK) != 0);
                sfmmu_mlist_exit(pml);
                SFMMU_HASH_UNLOCK(hmebp);
                page_unlock(pp);
                locked = 0;
                goto rehash;
        }

        if (!VN_ISKAS(vp)) {
                /*
                 * This is not a segkmem page but another page which
                 * has been kernel mapped.
                 */
                sfmmu_mlist_exit(pml);
                SFMMU_HASH_UNLOCK(hmebp);
                if (locked)
                        page_unlock(pp);
                ASSERT(cookie == NULL);
                return;
        }

        if (cookie != NULL) {
                pahmep = (struct pa_hment *)cookie;
                sfhmep = &pahmep->sfment;
        } else {
                for (sfhmep = pp->p_mapping; sfhmep != NULL;
                    sfhmep = sfhmep->hme_next) {

                        /*
                         * skip va<->pa mappings
                         */
                        if (!IS_PAHME(sfhmep))
                                continue;

                        pahmep = sfhmep->hme_data;
                        ASSERT(pahmep != NULL);

                        /*
                         * if pa_hment matches, remove it
                         */
                        if ((pahmep->pvt == pvt) &&
                            (pahmep->addr == vaddr) &&
                            (pahmep->len == len)) {
                                break;
                        }
                }
        }

        if (sfhmep == NULL) {
                if (!panicstr) {
                        panic("hat_delete_callback: pa_hment not found, pp %p",
                            (void *)pp);
                }
                return;
        }

        /*
         * Note: at this point a valid kernel mapping must still be
         * present on this page.
         */
        pp->p_share--;
        if (pp->p_share <= 0)
                panic("hat_delete_callback: zero p_share");

        if (--pahmep->refcnt == 0) {
                if (pahmep->flags != 0)
                        panic("hat_delete_callback: pa_hment is busy");

                /*
                 * Remove sfhmep from the mapping list for the page.
                 */
                if (sfhmep->hme_prev) {
                        sfhmep->hme_prev->hme_next = sfhmep->hme_next;
                } else {
                        pp->p_mapping = sfhmep->hme_next;
                }

                if (sfhmep->hme_next)
                        sfhmep->hme_next->hme_prev = sfhmep->hme_prev;

                sfmmu_mlist_exit(pml);
                SFMMU_HASH_UNLOCK(hmebp);

                if (locked)
                        page_unlock(pp);

                kmem_cache_free(pa_hment_cache, pahmep);
                return;
        }

        sfmmu_mlist_exit(pml);
        SFMMU_HASH_UNLOCK(hmebp);
        if (locked)
                page_unlock(pp);
}

/*
 * hat_probe returns 1 if the translation for the address 'addr' is
 * loaded, zero otherwise.
 *
 * hat_probe should be used only for advisorary purposes because it may
 * occasionally return the wrong value. The implementation must guarantee that
 * returning the wrong value is a very rare event. hat_probe is used
 * to implement optimizations in the segment drivers.
 *
 */
int
hat_probe(struct hat *sfmmup, caddr_t addr)
{
        pfn_t pfn;
        tte_t tte;

        ASSERT(sfmmup != NULL);

        ASSERT((sfmmup == ksfmmup) || AS_LOCK_HELD(sfmmup->sfmmu_as));

        if (sfmmup == ksfmmup) {
                while ((pfn = sfmmu_vatopfn(addr, sfmmup, &tte))
                    == PFN_SUSPENDED) {
                        sfmmu_vatopfn_suspended(addr, sfmmup, &tte);
                }
        } else {
                pfn = sfmmu_uvatopfn(addr, sfmmup, NULL);
        }

        if (pfn != PFN_INVALID)
                return (1);
        else
                return (0);
}

ssize_t
hat_getpagesize(struct hat *sfmmup, caddr_t addr)
{
        tte_t tte;

        if (sfmmup == ksfmmup) {
                if (sfmmu_vatopfn(addr, sfmmup, &tte) == PFN_INVALID) {
                        return (-1);
                }
        } else {
                if (sfmmu_uvatopfn(addr, sfmmup, &tte) == PFN_INVALID) {
                        return (-1);
                }
        }

        ASSERT(TTE_IS_VALID(&tte));
        return (TTEBYTES(TTE_CSZ(&tte)));
}

uint_t
hat_getattr(struct hat *sfmmup, caddr_t addr, uint_t *attr)
{
        tte_t tte;

        if (sfmmup == ksfmmup) {
                if (sfmmu_vatopfn(addr, sfmmup, &tte) == PFN_INVALID) {
                        tte.ll = 0;
                }
        } else {
                if (sfmmu_uvatopfn(addr, sfmmup, &tte) == PFN_INVALID) {
                        tte.ll = 0;
                }
        }
        if (TTE_IS_VALID(&tte)) {
                *attr = sfmmu_ptov_attr(&tte);
                return (0);
        }
        *attr = 0;
        return ((uint_t)0xffffffff);
}

/*
 * Enables more attributes on specified address range (ie. logical OR)
 */
void
hat_setattr(struct hat *hat, caddr_t addr, size_t len, uint_t attr)
{
        ASSERT(hat->sfmmu_as != NULL);

        sfmmu_chgattr(hat, addr, len, attr, SFMMU_SETATTR);
}

/*
 * Assigns attributes to the specified address range.  All the attributes
 * are specified.
 */
void
hat_chgattr(struct hat *hat, caddr_t addr, size_t len, uint_t attr)
{
        ASSERT(hat->sfmmu_as != NULL);

        sfmmu_chgattr(hat, addr, len, attr, SFMMU_CHGATTR);
}

/*
 * Remove attributes on the specified address range (ie. loginal NAND)
 */
void
hat_clrattr(struct hat *hat, caddr_t addr, size_t len, uint_t attr)
{
        ASSERT(hat->sfmmu_as != NULL);

        sfmmu_chgattr(hat, addr, len, attr, SFMMU_CLRATTR);
}

/*
 * Change attributes on an address range to that specified by attr and mode.
 */
static void
sfmmu_chgattr(struct hat *sfmmup, caddr_t addr, size_t len, uint_t attr,
    int mode)
{
        struct hmehash_bucket *hmebp;
        hmeblk_tag hblktag;
        int hmeshift, hashno = 1;
        struct hme_blk *hmeblkp, *list = NULL;
        caddr_t endaddr;
        cpuset_t cpuset;
        demap_range_t dmr;

        CPUSET_ZERO(cpuset);

        ASSERT((sfmmup == ksfmmup) || AS_LOCK_HELD(sfmmup->sfmmu_as));
        ASSERT((len & MMU_PAGEOFFSET) == 0);
        ASSERT(((uintptr_t)addr & MMU_PAGEOFFSET) == 0);

        if ((attr & PROT_USER) && (mode != SFMMU_CLRATTR) &&
            ((addr + len) > (caddr_t)USERLIMIT)) {
                panic("user addr %p in kernel space",
                    (void *)addr);
        }

        endaddr = addr + len;
        hblktag.htag_id = sfmmup;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;
        DEMAP_RANGE_INIT(sfmmup, &dmr);

        while (addr < endaddr) {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(sfmmup, addr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_SEARCH(hmebp, hblktag, hmeblkp, &list);
                if (hmeblkp != NULL) {
                        ASSERT(!hmeblkp->hblk_shared);
                        /*
                         * We've encountered a shadow hmeblk so skip the range
                         * of the next smaller mapping size.
                         */
                        if (hmeblkp->hblk_shw_bit) {
                                ASSERT(sfmmup != ksfmmup);
                                ASSERT(hashno > 1);
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(hashno - 1));
                        } else {
                                addr = sfmmu_hblk_chgattr(sfmmup,
                                    hmeblkp, addr, endaddr, &dmr, attr, mode);
                        }
                        SFMMU_HASH_UNLOCK(hmebp);
                        hashno = 1;
                        continue;
                }
                SFMMU_HASH_UNLOCK(hmebp);

                if (!HME_REHASH(sfmmup) || (hashno >= mmu_hashcnt)) {
                        /*
                         * We have traversed the whole list and rehashed
                         * if necessary without finding the address to chgattr.
                         * This is ok, so we increment the address by the
                         * smallest hmeblk range for kernel mappings or for
                         * user mappings with no large pages, and the largest
                         * hmeblk range, to account for shadow hmeblks, for
                         * user mappings with large pages and continue.
                         */
                        if (sfmmup == ksfmmup)
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(1));
                        else
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(hashno));
                        hashno = 1;
                } else {
                        hashno++;
                }
        }

        sfmmu_hblks_list_purge(&list, 0);
        DEMAP_RANGE_FLUSH(&dmr);
        cpuset = sfmmup->sfmmu_cpusran;
        xt_sync(cpuset);
}

/*
 * This function chgattr on a range of addresses in an hmeblk.  It returns the
 * next addres that needs to be chgattr.
 * It should be called with the hash lock held.
 * XXX It should be possible to optimize chgattr by not flushing every time but
 * on the other hand:
 * 1. do one flush crosscall.
 * 2. only flush if we are increasing permissions (make sure this will work)
 */
static caddr_t
sfmmu_hblk_chgattr(struct hat *sfmmup, struct hme_blk *hmeblkp, caddr_t addr,
    caddr_t endaddr, demap_range_t *dmrp, uint_t attr, int mode)
{
        tte_t tte, tteattr, tteflags, ttemod;
        struct sf_hment *sfhmep;
        int ttesz;
        struct page *pp = NULL;
        kmutex_t *pml, *pmtx;
        int ret;
        int use_demap_range;
#if defined(SF_ERRATA_57)
        int check_exec;
#endif

        ASSERT(in_hblk_range(hmeblkp, addr));
        ASSERT(hmeblkp->hblk_shw_bit == 0);
        ASSERT(!hmeblkp->hblk_shared);

        endaddr = MIN(endaddr, get_hblk_endaddr(hmeblkp));
        ttesz = get_hblk_ttesz(hmeblkp);

        /*
         * Flush the current demap region if addresses have been
         * skipped or the page size doesn't match.
         */
        use_demap_range = (TTEBYTES(ttesz) == DEMAP_RANGE_PGSZ(dmrp));
        if (use_demap_range) {
                DEMAP_RANGE_CONTINUE(dmrp, addr, endaddr);
        } else if (dmrp != NULL) {
                DEMAP_RANGE_FLUSH(dmrp);
        }

        tteattr.ll = sfmmu_vtop_attr(attr, mode, &tteflags);
#if defined(SF_ERRATA_57)
        check_exec = (sfmmup != ksfmmup) &&
            AS_TYPE_64BIT(sfmmup->sfmmu_as) &&
            TTE_IS_EXECUTABLE(&tteattr);
#endif
        HBLKTOHME(sfhmep, hmeblkp, addr);
        while (addr < endaddr) {
                sfmmu_copytte(&sfhmep->hme_tte, &tte);
                if (TTE_IS_VALID(&tte)) {
                        if ((tte.ll & tteflags.ll) == tteattr.ll) {
                                /*
                                 * if the new attr is the same as old
                                 * continue
                                 */
                                goto next_addr;
                        }
                        if (!TTE_IS_WRITABLE(&tteattr)) {
                                /*
                                 * make sure we clear hw modify bit if we
                                 * removing write protections
                                 */
                                tteflags.tte_intlo |= TTE_HWWR_INT;
                        }

                        pml = NULL;
                        pp = sfhmep->hme_page;
                        if (pp) {
                                pml = sfmmu_mlist_enter(pp);
                        }

                        if (pp != sfhmep->hme_page) {
                                /*
                                 * tte must have been unloaded.
                                 */
                                ASSERT(pml);
                                sfmmu_mlist_exit(pml);
                                continue;
                        }

                        ASSERT(pp == NULL || sfmmu_mlist_held(pp));

                        ttemod = tte;
                        ttemod.ll = (ttemod.ll & ~tteflags.ll) | tteattr.ll;
                        ASSERT(TTE_TO_TTEPFN(&ttemod) == TTE_TO_TTEPFN(&tte));

#if defined(SF_ERRATA_57)
                        if (check_exec && addr < errata57_limit)
                                ttemod.tte_exec_perm = 0;
#endif
                        ret = sfmmu_modifytte_try(&tte, &ttemod,
                            &sfhmep->hme_tte);

                        if (ret < 0) {
                                /* tte changed underneath us */
                                if (pml) {
                                        sfmmu_mlist_exit(pml);
                                }
                                continue;
                        }

                        if (tteflags.tte_intlo & TTE_HWWR_INT) {
                                /*
                                 * need to sync if we are clearing modify bit.
                                 */
                                sfmmu_ttesync(sfmmup, addr, &tte, pp);
                        }

                        if (pp && PP_ISRO(pp)) {
                                if (tteattr.tte_intlo & TTE_WRPRM_INT) {
                                        pmtx = sfmmu_page_enter(pp);
                                        PP_CLRRO(pp);
                                        sfmmu_page_exit(pmtx);
                                }
                        }

                        if (ret > 0 && use_demap_range) {
                                DEMAP_RANGE_MARKPG(dmrp, addr);
                        } else if (ret > 0) {
                                sfmmu_tlb_demap(addr, sfmmup, hmeblkp, 0, 0);
                        }

                        if (pml) {
                                sfmmu_mlist_exit(pml);
                        }
                }
next_addr:
                addr += TTEBYTES(ttesz);
                sfhmep++;
                DEMAP_RANGE_NEXTPG(dmrp);
        }
        return (addr);
}

/*
 * This routine converts virtual attributes to physical ones.  It will
 * update the tteflags field with the tte mask corresponding to the attributes
 * affected and it returns the new attributes.  It will also clear the modify
 * bit if we are taking away write permission.  This is necessary since the
 * modify bit is the hardware permission bit and we need to clear it in order
 * to detect write faults.
 */
static uint64_t
sfmmu_vtop_attr(uint_t attr, int mode, tte_t *ttemaskp)
{
        tte_t ttevalue;

        ASSERT(!(attr & ~SFMMU_LOAD_ALLATTR));

        switch (mode) {
        case SFMMU_CHGATTR:
                /* all attributes specified */
                ttevalue.tte_inthi = MAKE_TTEATTR_INTHI(attr);
                ttevalue.tte_intlo = MAKE_TTEATTR_INTLO(attr);
                ttemaskp->tte_inthi = TTEINTHI_ATTR;
                ttemaskp->tte_intlo = TTEINTLO_ATTR;
                break;
        case SFMMU_SETATTR:
                ASSERT(!(attr & ~HAT_PROT_MASK));
                ttemaskp->ll = 0;
                ttevalue.ll = 0;
                /*
                 * a valid tte implies exec and read for sfmmu
                 * so no need to do anything about them.
                 * since priviledged access implies user access
                 * PROT_USER doesn't make sense either.
                 */
                if (attr & PROT_WRITE) {
                        ttemaskp->tte_intlo |= TTE_WRPRM_INT;
                        ttevalue.tte_intlo |= TTE_WRPRM_INT;
                }
                break;
        case SFMMU_CLRATTR:
                /* attributes will be nand with current ones */
                if (attr & ~(PROT_WRITE | PROT_USER)) {
                        panic("sfmmu: attr %x not supported", attr);
                }
                ttemaskp->ll = 0;
                ttevalue.ll = 0;
                if (attr & PROT_WRITE) {
                        /* clear both writable and modify bit */
                        ttemaskp->tte_intlo |= TTE_WRPRM_INT | TTE_HWWR_INT;
                }
                if (attr & PROT_USER) {
                        ttemaskp->tte_intlo |= TTE_PRIV_INT;
                        ttevalue.tte_intlo |= TTE_PRIV_INT;
                }
                break;
        default:
                panic("sfmmu_vtop_attr: bad mode %x", mode);
        }
        ASSERT(TTE_TO_TTEPFN(&ttevalue) == 0);
        return (ttevalue.ll);
}

static uint_t
sfmmu_ptov_attr(tte_t *ttep)
{
        uint_t attr;

        ASSERT(TTE_IS_VALID(ttep));

        attr = PROT_READ;

        if (TTE_IS_WRITABLE(ttep)) {
                attr |= PROT_WRITE;
        }
        if (TTE_IS_EXECUTABLE(ttep)) {
                attr |= PROT_EXEC;
        }
        if (!TTE_IS_PRIVILEGED(ttep)) {
                attr |= PROT_USER;
        }
        if (TTE_IS_NFO(ttep)) {
                attr |= HAT_NOFAULT;
        }
        if (TTE_IS_NOSYNC(ttep)) {
                attr |= HAT_NOSYNC;
        }
        if (TTE_IS_SIDEFFECT(ttep)) {
                attr |= SFMMU_SIDEFFECT;
        }
        if (!TTE_IS_VCACHEABLE(ttep)) {
                attr |= SFMMU_UNCACHEVTTE;
        }
        if (!TTE_IS_PCACHEABLE(ttep)) {
                attr |= SFMMU_UNCACHEPTTE;
        }
        return (attr);
}

/*
 * hat_chgprot is a deprecated hat call.  New segment drivers
 * should store all attributes and use hat_*attr calls.
 *
 * Change the protections in the virtual address range
 * given to the specified virtual protection.  If vprot is ~PROT_WRITE,
 * then remove write permission, leaving the other
 * permissions unchanged.  If vprot is ~PROT_USER, remove user permissions.
 *
 */
void
hat_chgprot(struct hat *sfmmup, caddr_t addr, size_t len, uint_t vprot)
{
        struct hmehash_bucket *hmebp;
        hmeblk_tag hblktag;
        int hmeshift, hashno = 1;
        struct hme_blk *hmeblkp, *list = NULL;
        caddr_t endaddr;
        cpuset_t cpuset;
        demap_range_t dmr;

        ASSERT((len & MMU_PAGEOFFSET) == 0);
        ASSERT(((uintptr_t)addr & MMU_PAGEOFFSET) == 0);

        ASSERT(sfmmup->sfmmu_as != NULL);

        CPUSET_ZERO(cpuset);

        if ((vprot != (uint_t)~PROT_WRITE) && (vprot & PROT_USER) &&
            ((addr + len) > (caddr_t)USERLIMIT)) {
                panic("user addr %p vprot %x in kernel space",
                    (void *)addr, vprot);
        }
        endaddr = addr + len;
        hblktag.htag_id = sfmmup;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;
        DEMAP_RANGE_INIT(sfmmup, &dmr);

        while (addr < endaddr) {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(sfmmup, addr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_SEARCH(hmebp, hblktag, hmeblkp, &list);
                if (hmeblkp != NULL) {
                        ASSERT(!hmeblkp->hblk_shared);
                        /*
                         * We've encountered a shadow hmeblk so skip the range
                         * of the next smaller mapping size.
                         */
                        if (hmeblkp->hblk_shw_bit) {
                                ASSERT(sfmmup != ksfmmup);
                                ASSERT(hashno > 1);
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(hashno - 1));
                        } else {
                                addr = sfmmu_hblk_chgprot(sfmmup, hmeblkp,
                                    addr, endaddr, &dmr, vprot);
                        }
                        SFMMU_HASH_UNLOCK(hmebp);
                        hashno = 1;
                        continue;
                }
                SFMMU_HASH_UNLOCK(hmebp);

                if (!HME_REHASH(sfmmup) || (hashno >= mmu_hashcnt)) {
                        /*
                         * We have traversed the whole list and rehashed
                         * if necessary without finding the address to chgprot.
                         * This is ok so we increment the address by the
                         * smallest hmeblk range for kernel mappings and the
                         * largest hmeblk range, to account for shadow hmeblks,
                         * for user mappings and continue.
                         */
                        if (sfmmup == ksfmmup)
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(1));
                        else
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(hashno));
                        hashno = 1;
                } else {
                        hashno++;
                }
        }

        sfmmu_hblks_list_purge(&list, 0);
        DEMAP_RANGE_FLUSH(&dmr);
        cpuset = sfmmup->sfmmu_cpusran;
        xt_sync(cpuset);
}

/*
 * This function chgprots a range of addresses in an hmeblk.  It returns the
 * next addres that needs to be chgprot.
 * It should be called with the hash lock held.
 * XXX It shold be possible to optimize chgprot by not flushing every time but
 * on the other hand:
 * 1. do one flush crosscall.
 * 2. only flush if we are increasing permissions (make sure this will work)
 */
static caddr_t
sfmmu_hblk_chgprot(sfmmu_t *sfmmup, struct hme_blk *hmeblkp, caddr_t addr,
    caddr_t endaddr, demap_range_t *dmrp, uint_t vprot)
{
        uint_t pprot;
        tte_t tte, ttemod;
        struct sf_hment *sfhmep;
        uint_t tteflags;
        int ttesz;
        struct page *pp = NULL;
        kmutex_t *pml, *pmtx;
        int ret;
        int use_demap_range;
#if defined(SF_ERRATA_57)
        int check_exec;
#endif

        ASSERT(in_hblk_range(hmeblkp, addr));
        ASSERT(hmeblkp->hblk_shw_bit == 0);
        ASSERT(!hmeblkp->hblk_shared);

#ifdef DEBUG
        if (get_hblk_ttesz(hmeblkp) != TTE8K &&
            (endaddr < get_hblk_endaddr(hmeblkp))) {
                panic("sfmmu_hblk_chgprot: partial chgprot of large page");
        }
#endif /* DEBUG */

        endaddr = MIN(endaddr, get_hblk_endaddr(hmeblkp));
        ttesz = get_hblk_ttesz(hmeblkp);

        pprot = sfmmu_vtop_prot(vprot, &tteflags);
#if defined(SF_ERRATA_57)
        check_exec = (sfmmup != ksfmmup) &&
            AS_TYPE_64BIT(sfmmup->sfmmu_as) &&
            ((vprot & PROT_EXEC) == PROT_EXEC);
#endif
        HBLKTOHME(sfhmep, hmeblkp, addr);

        /*
         * Flush the current demap region if addresses have been
         * skipped or the page size doesn't match.
         */
        use_demap_range = (TTEBYTES(ttesz) == MMU_PAGESIZE);
        if (use_demap_range) {
                DEMAP_RANGE_CONTINUE(dmrp, addr, endaddr);
        } else if (dmrp != NULL) {
                DEMAP_RANGE_FLUSH(dmrp);
        }

        while (addr < endaddr) {
                sfmmu_copytte(&sfhmep->hme_tte, &tte);
                if (TTE_IS_VALID(&tte)) {
                        if (TTE_GET_LOFLAGS(&tte, tteflags) == pprot) {
                                /*
                                 * if the new protection is the same as old
                                 * continue
                                 */
                                goto next_addr;
                        }
                        pml = NULL;
                        pp = sfhmep->hme_page;
                        if (pp) {
                                pml = sfmmu_mlist_enter(pp);
                        }
                        if (pp != sfhmep->hme_page) {
                                /*
                                 * tte most have been unloaded
                                 * underneath us.  Recheck
                                 */
                                ASSERT(pml);
                                sfmmu_mlist_exit(pml);
                                continue;
                        }

                        ASSERT(pp == NULL || sfmmu_mlist_held(pp));

                        ttemod = tte;
                        TTE_SET_LOFLAGS(&ttemod, tteflags, pprot);
#if defined(SF_ERRATA_57)
                        if (check_exec && addr < errata57_limit)
                                ttemod.tte_exec_perm = 0;
#endif
                        ret = sfmmu_modifytte_try(&tte, &ttemod,
                            &sfhmep->hme_tte);

                        if (ret < 0) {
                                /* tte changed underneath us */
                                if (pml) {
                                        sfmmu_mlist_exit(pml);
                                }
                                continue;
                        }

                        if (tteflags & TTE_HWWR_INT) {
                                /*
                                 * need to sync if we are clearing modify bit.
                                 */
                                sfmmu_ttesync(sfmmup, addr, &tte, pp);
                        }

                        if (pp && PP_ISRO(pp)) {
                                if (pprot & TTE_WRPRM_INT) {
                                        pmtx = sfmmu_page_enter(pp);
                                        PP_CLRRO(pp);
                                        sfmmu_page_exit(pmtx);
                                }
                        }

                        if (ret > 0 && use_demap_range) {
                                DEMAP_RANGE_MARKPG(dmrp, addr);
                        } else if (ret > 0) {
                                sfmmu_tlb_demap(addr, sfmmup, hmeblkp, 0, 0);
                        }

                        if (pml) {
                                sfmmu_mlist_exit(pml);
                        }
                }
next_addr:
                addr += TTEBYTES(ttesz);
                sfhmep++;
                DEMAP_RANGE_NEXTPG(dmrp);
        }
        return (addr);
}

/*
 * This routine is deprecated and should only be used by hat_chgprot.
 * The correct routine is sfmmu_vtop_attr.
 * This routine converts virtual page protections to physical ones.  It will
 * update the tteflags field with the tte mask corresponding to the protections
 * affected and it returns the new protections.  It will also clear the modify
 * bit if we are taking away write permission.  This is necessary since the
 * modify bit is the hardware permission bit and we need to clear it in order
 * to detect write faults.
 * It accepts the following special protections:
 * ~PROT_WRITE = remove write permissions.
 * ~PROT_USER = remove user permissions.
 */
static uint_t
sfmmu_vtop_prot(uint_t vprot, uint_t *tteflagsp)
{
        if (vprot == (uint_t)~PROT_WRITE) {
                *tteflagsp = TTE_WRPRM_INT | TTE_HWWR_INT;
                return (0);             /* will cause wrprm to be cleared */
        }
        if (vprot == (uint_t)~PROT_USER) {
                *tteflagsp = TTE_PRIV_INT;
                return (0);             /* will cause privprm to be cleared */
        }
        if ((vprot == 0) || (vprot == PROT_USER) ||
            ((vprot & PROT_ALL) != vprot)) {
                panic("sfmmu_vtop_prot -- bad prot %x", vprot);
        }

        switch (vprot) {
        case (PROT_READ):
        case (PROT_EXEC):
        case (PROT_EXEC | PROT_READ):
                *tteflagsp = TTE_PRIV_INT | TTE_WRPRM_INT | TTE_HWWR_INT;
                return (TTE_PRIV_INT);          /* set prv and clr wrt */
        case (PROT_WRITE):
        case (PROT_WRITE | PROT_READ):
        case (PROT_EXEC | PROT_WRITE):
        case (PROT_EXEC | PROT_WRITE | PROT_READ):
                *tteflagsp = TTE_PRIV_INT | TTE_WRPRM_INT;
                return (TTE_PRIV_INT | TTE_WRPRM_INT);  /* set prv and wrt */
        case (PROT_USER | PROT_READ):
        case (PROT_USER | PROT_EXEC):
        case (PROT_USER | PROT_EXEC | PROT_READ):
                *tteflagsp = TTE_PRIV_INT | TTE_WRPRM_INT | TTE_HWWR_INT;
                return (0);                     /* clr prv and wrt */
        case (PROT_USER | PROT_WRITE):
        case (PROT_USER | PROT_WRITE | PROT_READ):
        case (PROT_USER | PROT_EXEC | PROT_WRITE):
        case (PROT_USER | PROT_EXEC | PROT_WRITE | PROT_READ):
                *tteflagsp = TTE_PRIV_INT | TTE_WRPRM_INT;
                return (TTE_WRPRM_INT);         /* clr prv and set wrt */
        default:
                panic("sfmmu_vtop_prot -- bad prot %x", vprot);
        }
        return (0);
}

/*
 * Alternate unload for very large virtual ranges. With a true 64 bit VA,
 * the normal algorithm would take too long for a very large VA range with
 * few real mappings. This routine just walks thru all HMEs in the global
 * hash table to find and remove mappings.
 */
static void
hat_unload_large_virtual(struct hat *sfmmup, caddr_t startaddr, size_t len,
    uint_t flags, hat_callback_t *callback)
{
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp;
        struct hme_blk *pr_hblk = NULL;
        struct hme_blk *nx_hblk;
        struct hme_blk *list = NULL;
        int i;
        demap_range_t dmr, *dmrp;
        cpuset_t cpuset;
        caddr_t endaddr = startaddr + len;
        caddr_t sa;
        caddr_t ea;
        caddr_t cb_sa[MAX_CB_ADDR];
        caddr_t cb_ea[MAX_CB_ADDR];
        int     addr_cnt = 0;
        int     a = 0;

        if (sfmmup->sfmmu_free) {
                dmrp = NULL;
        } else {
                dmrp = &dmr;
                DEMAP_RANGE_INIT(sfmmup, dmrp);
        }

        /*
         * Loop through all the hash buckets of HME blocks looking for matches.
         */
        for (i = 0; i <= UHMEHASH_SZ; i++) {
                hmebp = &uhme_hash[i];
                SFMMU_HASH_LOCK(hmebp);
                hmeblkp = hmebp->hmeblkp;
                pr_hblk = NULL;
                while (hmeblkp) {
                        nx_hblk = hmeblkp->hblk_next;

                        /*
                         * skip if not this context, if a shadow block or
                         * if the mapping is not in the requested range
                         */
                        if (hmeblkp->hblk_tag.htag_id != sfmmup ||
                            hmeblkp->hblk_shw_bit ||
                            (sa = (caddr_t)get_hblk_base(hmeblkp)) >= endaddr ||
                            (ea = get_hblk_endaddr(hmeblkp)) <= startaddr) {
                                pr_hblk = hmeblkp;
                                goto next_block;
                        }

                        ASSERT(!hmeblkp->hblk_shared);
                        /*
                         * unload if there are any current valid mappings
                         */
                        if (hmeblkp->hblk_vcnt != 0 ||
                            hmeblkp->hblk_hmecnt != 0)
                                (void) sfmmu_hblk_unload(sfmmup, hmeblkp,
                                    sa, ea, dmrp, flags);

                        /*
                         * on unmap we also release the HME block itself, once
                         * all mappings are gone.
                         */
                        if ((flags & HAT_UNLOAD_UNMAP) != 0 &&
                            !hmeblkp->hblk_vcnt &&
                            !hmeblkp->hblk_hmecnt) {
                                ASSERT(!hmeblkp->hblk_lckcnt);
                                sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk,
                                    &list, 0);
                        } else {
                                pr_hblk = hmeblkp;
                        }

                        if (callback == NULL)
                                goto next_block;

                        /*
                         * HME blocks may span more than one page, but we may be
                         * unmapping only one page, so check for a smaller range
                         * for the callback
                         */
                        if (sa < startaddr)
                                sa = startaddr;
                        if (--ea > endaddr)
                                ea = endaddr - 1;

                        cb_sa[addr_cnt] = sa;
                        cb_ea[addr_cnt] = ea;
                        if (++addr_cnt == MAX_CB_ADDR) {
                                if (dmrp != NULL) {
                                        DEMAP_RANGE_FLUSH(dmrp);
                                        cpuset = sfmmup->sfmmu_cpusran;
                                        xt_sync(cpuset);
                                }

                                for (a = 0; a < MAX_CB_ADDR; ++a) {
                                        callback->hcb_start_addr = cb_sa[a];
                                        callback->hcb_end_addr = cb_ea[a];
                                        callback->hcb_function(callback);
                                }
                                addr_cnt = 0;
                        }

next_block:
                        hmeblkp = nx_hblk;
                }
                SFMMU_HASH_UNLOCK(hmebp);
        }

        sfmmu_hblks_list_purge(&list, 0);
        if (dmrp != NULL) {
                DEMAP_RANGE_FLUSH(dmrp);
                cpuset = sfmmup->sfmmu_cpusran;
                xt_sync(cpuset);
        }

        for (a = 0; a < addr_cnt; ++a) {
                callback->hcb_start_addr = cb_sa[a];
                callback->hcb_end_addr = cb_ea[a];
                callback->hcb_function(callback);
        }

        /*
         * Check TSB and TLB page sizes if the process isn't exiting.
         */
        if (!sfmmup->sfmmu_free)
                sfmmu_check_page_sizes(sfmmup, 0);
}

/*
 * Unload all the mappings in the range [addr..addr+len). addr and len must
 * be MMU_PAGESIZE aligned.
 */

extern struct seg *segkmap;
#define ISSEGKMAP(sfmmup, addr) (sfmmup == ksfmmup && \
segkmap->s_base <= (addr) && (addr) < (segkmap->s_base + segkmap->s_size))


void
hat_unload_callback(struct hat *sfmmup, caddr_t addr, size_t len, uint_t flags,
    hat_callback_t *callback)
{
        struct hmehash_bucket *hmebp;
        hmeblk_tag hblktag;
        int hmeshift, hashno, iskernel;
        struct hme_blk *hmeblkp, *pr_hblk, *list = NULL;
        caddr_t endaddr;
        cpuset_t cpuset;
        int addr_count = 0;
        int a;
        caddr_t cb_start_addr[MAX_CB_ADDR];
        caddr_t cb_end_addr[MAX_CB_ADDR];
        int issegkmap = ISSEGKMAP(sfmmup, addr);
        demap_range_t dmr, *dmrp;

        ASSERT(sfmmup->sfmmu_as != NULL);

        ASSERT((sfmmup == ksfmmup) || (flags & HAT_UNLOAD_OTHER) || \
            AS_LOCK_HELD(sfmmup->sfmmu_as));

        ASSERT(sfmmup != NULL);
        ASSERT((len & MMU_PAGEOFFSET) == 0);
        ASSERT(!((uintptr_t)addr & MMU_PAGEOFFSET));

        /*
         * Probing through a large VA range (say 63 bits) will be slow, even
         * at 4 Meg steps between the probes. So, when the virtual address range
         * is very large, search the HME entries for what to unload.
         *
         *      len >> TTE_PAGE_SHIFT(TTE4M) is the # of 4Meg probes we'd need
         *
         *      UHMEHASH_SZ is number of hash buckets to examine
         *
         */
        if (sfmmup != KHATID && (len >> TTE_PAGE_SHIFT(TTE4M)) > UHMEHASH_SZ) {
                hat_unload_large_virtual(sfmmup, addr, len, flags, callback);
                return;
        }

        CPUSET_ZERO(cpuset);

        /*
         * If the process is exiting, we can save a lot of fuss since
         * we'll flush the TLB when we free the ctx anyway.
         */
        if (sfmmup->sfmmu_free) {
                dmrp = NULL;
        } else {
                dmrp = &dmr;
                DEMAP_RANGE_INIT(sfmmup, dmrp);
        }

        endaddr = addr + len;
        hblktag.htag_id = sfmmup;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;

        /*
         * It is likely for the vm to call unload over a wide range of
         * addresses that are actually very sparsely populated by
         * translations.  In order to speed this up the sfmmu hat supports
         * the concept of shadow hmeblks. Dummy large page hmeblks that
         * correspond to actual small translations are allocated at tteload
         * time and are referred to as shadow hmeblks.  Now, during unload
         * time, we first check if we have a shadow hmeblk for that
         * translation.  The absence of one means the corresponding address
         * range is empty and can be skipped.
         *
         * The kernel is an exception to above statement and that is why
         * we don't use shadow hmeblks and hash starting from the smallest
         * page size.
         */
        if (sfmmup == KHATID) {
                iskernel = 1;
                hashno = TTE64K;
        } else {
                iskernel = 0;
                if (mmu_page_sizes == max_mmu_page_sizes) {
                        hashno = TTE256M;
                } else {
                        hashno = TTE4M;
                }
        }
        while (addr < endaddr) {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(sfmmup, addr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_SEARCH_PREV(hmebp, hblktag, hmeblkp, pr_hblk, &list);
                if (hmeblkp == NULL) {
                        /*
                         * didn't find an hmeblk. skip the appropiate
                         * address range.
                         */
                        SFMMU_HASH_UNLOCK(hmebp);
                        if (iskernel) {
                                if (hashno < mmu_hashcnt) {
                                        hashno++;
                                        continue;
                                } else {
                                        hashno = TTE64K;
                                        addr = (caddr_t)roundup((uintptr_t)addr
                                            + 1, MMU_PAGESIZE64K);
                                        continue;
                                }
                        }
                        addr = (caddr_t)roundup((uintptr_t)addr + 1,
                            (1 << hmeshift));
                        if ((uintptr_t)addr & MMU_PAGEOFFSET512K) {
                                ASSERT(hashno == TTE64K);
                                continue;
                        }
                        if ((uintptr_t)addr & MMU_PAGEOFFSET4M) {
                                hashno = TTE512K;
                                continue;
                        }
                        if (mmu_page_sizes == max_mmu_page_sizes) {
                                if ((uintptr_t)addr & MMU_PAGEOFFSET32M) {
                                        hashno = TTE4M;
                                        continue;
                                }
                                if ((uintptr_t)addr & MMU_PAGEOFFSET256M) {
                                        hashno = TTE32M;
                                        continue;
                                }
                                hashno = TTE256M;
                                continue;
                        } else {
                                hashno = TTE4M;
                                continue;
                        }
                }
                ASSERT(hmeblkp);
                ASSERT(!hmeblkp->hblk_shared);
                if (!hmeblkp->hblk_vcnt && !hmeblkp->hblk_hmecnt) {
                        /*
                         * If the valid count is zero we can skip the range
                         * mapped by this hmeblk.
                         * We free hblks in the case of HAT_UNMAP.  HAT_UNMAP
                         * is used by segment drivers as a hint
                         * that the mapping resource won't be used any longer.
                         * The best example of this is during exit().
                         */
                        addr = (caddr_t)roundup((uintptr_t)addr + 1,
                            get_hblk_span(hmeblkp));
                        if ((flags & HAT_UNLOAD_UNMAP) ||
                            (iskernel && !issegkmap)) {
                                sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk,
                                    &list, 0);
                        }
                        SFMMU_HASH_UNLOCK(hmebp);

                        if (iskernel) {
                                hashno = TTE64K;
                                continue;
                        }
                        if ((uintptr_t)addr & MMU_PAGEOFFSET512K) {
                                ASSERT(hashno == TTE64K);
                                continue;
                        }
                        if ((uintptr_t)addr & MMU_PAGEOFFSET4M) {
                                hashno = TTE512K;
                                continue;
                        }
                        if (mmu_page_sizes == max_mmu_page_sizes) {
                                if ((uintptr_t)addr & MMU_PAGEOFFSET32M) {
                                        hashno = TTE4M;
                                        continue;
                                }
                                if ((uintptr_t)addr & MMU_PAGEOFFSET256M) {
                                        hashno = TTE32M;
                                        continue;
                                }
                                hashno = TTE256M;
                                continue;
                        } else {
                                hashno = TTE4M;
                                continue;
                        }
                }
                if (hmeblkp->hblk_shw_bit) {
                        /*
                         * If we encounter a shadow hmeblk we know there is
                         * smaller sized hmeblks mapping the same address space.
                         * Decrement the hash size and rehash.
                         */
                        ASSERT(sfmmup != KHATID);
                        hashno--;
                        SFMMU_HASH_UNLOCK(hmebp);
                        continue;
                }

                /*
                 * track callback address ranges.
                 * only start a new range when it's not contiguous
                 */
                if (callback != NULL) {
                        if (addr_count > 0 &&
                            addr == cb_end_addr[addr_count - 1])
                                --addr_count;
                        else
                                cb_start_addr[addr_count] = addr;
                }

                addr = sfmmu_hblk_unload(sfmmup, hmeblkp, addr, endaddr,
                    dmrp, flags);

                if (callback != NULL)
                        cb_end_addr[addr_count++] = addr;

                if (((flags & HAT_UNLOAD_UNMAP) || (iskernel && !issegkmap)) &&
                    !hmeblkp->hblk_vcnt && !hmeblkp->hblk_hmecnt) {
                        sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk, &list, 0);
                }
                SFMMU_HASH_UNLOCK(hmebp);

                /*
                 * Notify our caller as to exactly which pages
                 * have been unloaded. We do these in clumps,
                 * to minimize the number of xt_sync()s that need to occur.
                 */
                if (callback != NULL && addr_count == MAX_CB_ADDR) {
                        if (dmrp != NULL) {
                                DEMAP_RANGE_FLUSH(dmrp);
                                cpuset = sfmmup->sfmmu_cpusran;
                                xt_sync(cpuset);
                        }

                        for (a = 0; a < MAX_CB_ADDR; ++a) {
                                callback->hcb_start_addr = cb_start_addr[a];
                                callback->hcb_end_addr = cb_end_addr[a];
                                callback->hcb_function(callback);
                        }
                        addr_count = 0;
                }
                if (iskernel) {
                        hashno = TTE64K;
                        continue;
                }
                if ((uintptr_t)addr & MMU_PAGEOFFSET512K) {
                        ASSERT(hashno == TTE64K);
                        continue;
                }
                if ((uintptr_t)addr & MMU_PAGEOFFSET4M) {
                        hashno = TTE512K;
                        continue;
                }
                if (mmu_page_sizes == max_mmu_page_sizes) {
                        if ((uintptr_t)addr & MMU_PAGEOFFSET32M) {
                                hashno = TTE4M;
                                continue;
                        }
                        if ((uintptr_t)addr & MMU_PAGEOFFSET256M) {
                                hashno = TTE32M;
                                continue;
                        }
                        hashno = TTE256M;
                } else {
                        hashno = TTE4M;
                }
        }

        sfmmu_hblks_list_purge(&list, 0);
        if (dmrp != NULL) {
                DEMAP_RANGE_FLUSH(dmrp);
                cpuset = sfmmup->sfmmu_cpusran;
                xt_sync(cpuset);
        }
        if (callback && addr_count != 0) {
                for (a = 0; a < addr_count; ++a) {
                        callback->hcb_start_addr = cb_start_addr[a];
                        callback->hcb_end_addr = cb_end_addr[a];
                        callback->hcb_function(callback);
                }
        }

        /*
         * Check TSB and TLB page sizes if the process isn't exiting.
         */
        if (!sfmmup->sfmmu_free)
                sfmmu_check_page_sizes(sfmmup, 0);
}

/*
 * Unload all the mappings in the range [addr..addr+len). addr and len must
 * be MMU_PAGESIZE aligned.
 */
void
hat_unload(struct hat *sfmmup, caddr_t addr, size_t len, uint_t flags)
{
        hat_unload_callback(sfmmup, addr, len, flags, NULL);
}


/*
 * Find the largest mapping size for this page.
 */
int
fnd_mapping_sz(page_t *pp)
{
        int sz;
        int p_index;

        p_index = PP_MAPINDEX(pp);

        sz = 0;
        p_index >>= 1;  /* don't care about 8K bit */
        for (; p_index; p_index >>= 1) {
                sz++;
        }

        return (sz);
}

/*
 * This function unloads a range of addresses for an hmeblk.
 * It returns the next address to be unloaded.
 * It should be called with the hash lock held.
 */
static caddr_t
sfmmu_hblk_unload(struct hat *sfmmup, struct hme_blk *hmeblkp, caddr_t addr,
    caddr_t endaddr, demap_range_t *dmrp, uint_t flags)
{
        tte_t   tte, ttemod;
        struct  sf_hment *sfhmep;
        int     ttesz;
        long    ttecnt;
        page_t *pp;
        kmutex_t *pml;
        int ret;
        int use_demap_range;

        ASSERT(in_hblk_range(hmeblkp, addr));
        ASSERT(!hmeblkp->hblk_shw_bit);
        ASSERT(sfmmup != NULL || hmeblkp->hblk_shared);
        ASSERT(sfmmup == NULL || !hmeblkp->hblk_shared);
        ASSERT(dmrp == NULL || !hmeblkp->hblk_shared);

#ifdef DEBUG
        if (get_hblk_ttesz(hmeblkp) != TTE8K &&
            (endaddr < get_hblk_endaddr(hmeblkp))) {
                panic("sfmmu_hblk_unload: partial unload of large page");
        }
#endif /* DEBUG */

        endaddr = MIN(endaddr, get_hblk_endaddr(hmeblkp));
        ttesz = get_hblk_ttesz(hmeblkp);

        use_demap_range = ((dmrp == NULL) ||
            (TTEBYTES(ttesz) == DEMAP_RANGE_PGSZ(dmrp)));

        if (use_demap_range) {
                DEMAP_RANGE_CONTINUE(dmrp, addr, endaddr);
        } else if (dmrp != NULL) {
                DEMAP_RANGE_FLUSH(dmrp);
        }
        ttecnt = 0;
        HBLKTOHME(sfhmep, hmeblkp, addr);

        while (addr < endaddr) {
                pml = NULL;
                sfmmu_copytte(&sfhmep->hme_tte, &tte);
                if (TTE_IS_VALID(&tte)) {
                        pp = sfhmep->hme_page;
                        if (pp != NULL) {
                                pml = sfmmu_mlist_enter(pp);
                        }

                        /*
                         * Verify if hme still points to 'pp' now that
                         * we have p_mapping lock.
                         */
                        if (sfhmep->hme_page != pp) {
                                if (pp != NULL && sfhmep->hme_page != NULL) {
                                        ASSERT(pml != NULL);
                                        sfmmu_mlist_exit(pml);
                                        /* Re-start this iteration. */
                                        continue;
                                }
                                ASSERT((pp != NULL) &&
                                    (sfhmep->hme_page == NULL));
                                goto tte_unloaded;
                        }

                        /*
                         * This point on we have both HASH and p_mapping
                         * lock.
                         */
                        ASSERT(pp == sfhmep->hme_page);
                        ASSERT(pp == NULL || sfmmu_mlist_held(pp));

                        /*
                         * We need to loop on modify tte because it is
                         * possible for pagesync to come along and
                         * change the software bits beneath us.
                         *
                         * Page_unload can also invalidate the tte after
                         * we read tte outside of p_mapping lock.
                         */
again:
                        ttemod = tte;

                        TTE_SET_INVALID(&ttemod);
                        ret = sfmmu_modifytte_try(&tte, &ttemod,
                            &sfhmep->hme_tte);

                        if (ret <= 0) {
                                if (TTE_IS_VALID(&tte)) {
                                        ASSERT(ret < 0);
                                        goto again;
                                }
                                if (pp != NULL) {
                                        panic("sfmmu_hblk_unload: pp = 0x%p "
                                            "tte became invalid under mlist"
                                            " lock = 0x%p", (void *)pp,
                                            (void *)pml);
                                }
                                continue;
                        }

                        if (!(flags & HAT_UNLOAD_NOSYNC)) {
                                sfmmu_ttesync(sfmmup, addr, &tte, pp);
                        }

                        /*
                         * Ok- we invalidated the tte. Do the rest of the job.
                         */
                        ttecnt++;

                        if (flags & HAT_UNLOAD_UNLOCK) {
                                ASSERT(hmeblkp->hblk_lckcnt > 0);
                                atomic_dec_32(&hmeblkp->hblk_lckcnt);
                                HBLK_STACK_TRACE(hmeblkp, HBLK_UNLOCK);
                        }

                        /*
                         * Normally we would need to flush the page
                         * from the virtual cache at this point in
                         * order to prevent a potential cache alias
                         * inconsistency.
                         * The particular scenario we need to worry
                         * about is:
                         * Given:  va1 and va2 are two virtual address
                         * that alias and map the same physical
                         * address.
                         * 1.   mapping exists from va1 to pa and data
                         * has been read into the cache.
                         * 2.   unload va1.
                         * 3.   load va2 and modify data using va2.
                         * 4    unload va2.
                         * 5.   load va1 and reference data.  Unless we
                         * flush the data cache when we unload we will
                         * get stale data.
                         * Fortunately, page coloring eliminates the
                         * above scenario by remembering the color a
                         * physical page was last or is currently
                         * mapped to.  Now, we delay the flush until
                         * the loading of translations.  Only when the
                         * new translation is of a different color
                         * are we forced to flush.
                         */
                        if (use_demap_range) {
                                /*
                                 * Mark this page as needing a demap.
                                 */
                                DEMAP_RANGE_MARKPG(dmrp, addr);
                        } else {
                                ASSERT(sfmmup != NULL);
                                ASSERT(!hmeblkp->hblk_shared);
                                sfmmu_tlb_demap(addr, sfmmup, hmeblkp,
                                    sfmmup->sfmmu_free, 0);
                        }

                        if (pp) {
                                /*
                                 * Remove the hment from the mapping list
                                 */
                                ASSERT(hmeblkp->hblk_hmecnt > 0);

                                /*
                                 * Again, we cannot
                                 * ASSERT(hmeblkp->hblk_hmecnt <= NHMENTS);
                                 */
                                HME_SUB(sfhmep, pp);
                                membar_stst();
                                atomic_dec_16(&hmeblkp->hblk_hmecnt);
                        }

                        ASSERT(hmeblkp->hblk_vcnt > 0);
                        atomic_dec_16(&hmeblkp->hblk_vcnt);

                        ASSERT(hmeblkp->hblk_hmecnt || hmeblkp->hblk_vcnt ||
                            !hmeblkp->hblk_lckcnt);

#ifdef VAC
                        if (pp && (pp->p_nrm & (P_KPMC | P_KPMS | P_TNC))) {
                                if (PP_ISTNC(pp)) {
                                        /*
                                         * If page was temporary
                                         * uncached, try to recache
                                         * it. Note that HME_SUB() was
                                         * called above so p_index and
                                         * mlist had been updated.
                                         */
                                        conv_tnc(pp, ttesz);
                                } else if (pp->p_mapping == NULL) {
                                        ASSERT(kpm_enable);
                                        /*
                                         * Page is marked to be in VAC conflict
                                         * to an existing kpm mapping and/or is
                                         * kpm mapped using only the regular
                                         * pagesize.
                                         */
                                        sfmmu_kpm_hme_unload(pp);
                                }
                        }
#endif  /* VAC */
                } else if ((pp = sfhmep->hme_page) != NULL) {
                                /*
                                 * TTE is invalid but the hme
                                 * still exists. let pageunload
                                 * complete its job.
                                 */
                                ASSERT(pml == NULL);
                                pml = sfmmu_mlist_enter(pp);
                                if (sfhmep->hme_page != NULL) {
                                        sfmmu_mlist_exit(pml);
                                        continue;
                                }
                                ASSERT(sfhmep->hme_page == NULL);
                } else if (hmeblkp->hblk_hmecnt != 0) {
                        /*
                         * pageunload may have not finished decrementing
                         * hblk_vcnt and hblk_hmecnt. Find page_t if any and
                         * wait for pageunload to finish. Rely on pageunload
                         * to decrement hblk_hmecnt after hblk_vcnt.
                         */
                        pfn_t pfn = TTE_TO_TTEPFN(&tte);
                        ASSERT(pml == NULL);
                        if (pf_is_memory(pfn)) {
                                pp = page_numtopp_nolock(pfn);
                                if (pp != NULL) {
                                        pml = sfmmu_mlist_enter(pp);
                                        sfmmu_mlist_exit(pml);
                                        pml = NULL;
                                }
                        }
                }

tte_unloaded:
                /*
                 * At this point, the tte we are looking at
                 * should be unloaded, and hme has been unlinked
                 * from page too. This is important because in
                 * pageunload, it does ttesync() then HME_SUB.
                 * We need to make sure HME_SUB has been completed
                 * so we know ttesync() has been completed. Otherwise,
                 * at exit time, after return from hat layer, VM will
                 * release as structure which hat_setstat() (called
                 * by ttesync()) needs.
                 */
#ifdef DEBUG
                {
                        tte_t   dtte;

                        ASSERT(sfhmep->hme_page == NULL);

                        sfmmu_copytte(&sfhmep->hme_tte, &dtte);
                        ASSERT(!TTE_IS_VALID(&dtte));
                }
#endif

                if (pml) {
                        sfmmu_mlist_exit(pml);
                }

                addr += TTEBYTES(ttesz);
                sfhmep++;
                DEMAP_RANGE_NEXTPG(dmrp);
        }
        /*
         * For shared hmeblks this routine is only called when region is freed
         * and no longer referenced.  So no need to decrement ttecnt
         * in the region structure here.
         */
        if (ttecnt > 0 && sfmmup != NULL) {
                atomic_add_long(&sfmmup->sfmmu_ttecnt[ttesz], -ttecnt);
        }
        return (addr);
}

/*
 * Invalidate a virtual address range for the local CPU.
 * For best performance ensure that the va range is completely
 * mapped, otherwise the entire TLB will be flushed.
 */
void
hat_flush_range(struct hat *sfmmup, caddr_t va, size_t size)
{
        ssize_t sz;
        caddr_t endva = va + size;

        while (va < endva) {
                sz = hat_getpagesize(sfmmup, va);
                if (sz < 0) {
                        vtag_flushall();
                        break;
                }
                vtag_flushpage(va, (uint64_t)sfmmup);
                va += sz;
        }
}

/*
 * Synchronize all the mappings in the range [addr..addr+len).
 * Can be called with clearflag having two states:
 * HAT_SYNC_DONTZERO means just return the rm stats
 * HAT_SYNC_ZERORM means zero rm bits in the tte and return the stats
 */
void
hat_sync(struct hat *sfmmup, caddr_t addr, size_t len, uint_t clearflag)
{
        struct hmehash_bucket *hmebp;
        hmeblk_tag hblktag;
        int hmeshift, hashno = 1;
        struct hme_blk *hmeblkp, *list = NULL;
        caddr_t endaddr;
        cpuset_t cpuset;

        ASSERT((sfmmup == ksfmmup) || AS_LOCK_HELD(sfmmup->sfmmu_as));
        ASSERT((len & MMU_PAGEOFFSET) == 0);
        ASSERT((clearflag == HAT_SYNC_DONTZERO) ||
            (clearflag == HAT_SYNC_ZERORM));

        CPUSET_ZERO(cpuset);

        endaddr = addr + len;
        hblktag.htag_id = sfmmup;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;

        /*
         * Spitfire supports 4 page sizes.
         * Most pages are expected to be of the smallest page
         * size (8K) and these will not need to be rehashed. 64K
         * pages also don't need to be rehashed because the an hmeblk
         * spans 64K of address space. 512K pages might need 1 rehash and
         * and 4M pages 2 rehashes.
         */
        while (addr < endaddr) {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_bspage = HME_HASH_BSPAGE(addr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(sfmmup, addr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_SEARCH(hmebp, hblktag, hmeblkp, &list);
                if (hmeblkp != NULL) {
                        ASSERT(!hmeblkp->hblk_shared);
                        /*
                         * We've encountered a shadow hmeblk so skip the range
                         * of the next smaller mapping size.
                         */
                        if (hmeblkp->hblk_shw_bit) {
                                ASSERT(sfmmup != ksfmmup);
                                ASSERT(hashno > 1);
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(hashno - 1));
                        } else {
                                addr = sfmmu_hblk_sync(sfmmup, hmeblkp,
                                    addr, endaddr, clearflag);
                        }
                        SFMMU_HASH_UNLOCK(hmebp);
                        hashno = 1;
                        continue;
                }
                SFMMU_HASH_UNLOCK(hmebp);

                if (!HME_REHASH(sfmmup) || (hashno >= mmu_hashcnt)) {
                        /*
                         * We have traversed the whole list and rehashed
                         * if necessary without finding the address to sync.
                         * This is ok so we increment the address by the
                         * smallest hmeblk range for kernel mappings and the
                         * largest hmeblk range, to account for shadow hmeblks,
                         * for user mappings and continue.
                         */
                        if (sfmmup == ksfmmup)
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(1));
                        else
                                addr = (caddr_t)P2END((uintptr_t)addr,
                                    TTEBYTES(hashno));
                        hashno = 1;
                } else {
                        hashno++;
                }
        }
        sfmmu_hblks_list_purge(&list, 0);
        cpuset = sfmmup->sfmmu_cpusran;
        xt_sync(cpuset);
}

static caddr_t
sfmmu_hblk_sync(struct hat *sfmmup, struct hme_blk *hmeblkp, caddr_t addr,
    caddr_t endaddr, int clearflag)
{
        tte_t   tte, ttemod;
        struct sf_hment *sfhmep;
        int ttesz;
        struct page *pp;
        kmutex_t *pml;
        int ret;

        ASSERT(hmeblkp->hblk_shw_bit == 0);
        ASSERT(!hmeblkp->hblk_shared);

        endaddr = MIN(endaddr, get_hblk_endaddr(hmeblkp));

        ttesz = get_hblk_ttesz(hmeblkp);
        HBLKTOHME(sfhmep, hmeblkp, addr);

        while (addr < endaddr) {
                sfmmu_copytte(&sfhmep->hme_tte, &tte);
                if (TTE_IS_VALID(&tte)) {
                        pml = NULL;
                        pp = sfhmep->hme_page;
                        if (pp) {
                                pml = sfmmu_mlist_enter(pp);
                        }
                        if (pp != sfhmep->hme_page) {
                                /*
                                 * tte most have been unloaded
                                 * underneath us.  Recheck
                                 */
                                ASSERT(pml);
                                sfmmu_mlist_exit(pml);
                                continue;
                        }

                        ASSERT(pp == NULL || sfmmu_mlist_held(pp));

                        if (clearflag == HAT_SYNC_ZERORM) {
                                ttemod = tte;
                                TTE_CLR_RM(&ttemod);
                                ret = sfmmu_modifytte_try(&tte, &ttemod,
                                    &sfhmep->hme_tte);
                                if (ret < 0) {
                                        if (pml) {
                                                sfmmu_mlist_exit(pml);
                                        }
                                        continue;
                                }

                                if (ret > 0) {
                                        sfmmu_tlb_demap(addr, sfmmup,
                                            hmeblkp, 0, 0);
                                }
                        }
                        sfmmu_ttesync(sfmmup, addr, &tte, pp);
                        if (pml) {
                                sfmmu_mlist_exit(pml);
                        }
                }
                addr += TTEBYTES(ttesz);
                sfhmep++;
        }
        return (addr);
}

/*
 * This function will sync a tte to the page struct and it will
 * update the hat stats. Currently it allows us to pass a NULL pp
 * and we will simply update the stats.  We may want to change this
 * so we only keep stats for pages backed by pp's.
 */
static void
sfmmu_ttesync(struct hat *sfmmup, caddr_t addr, tte_t *ttep, page_t *pp)
{
        uint_t rm = 0;
        int     sz;
        pgcnt_t npgs;

        ASSERT(TTE_IS_VALID(ttep));

        if (TTE_IS_NOSYNC(ttep)) {
                return;
        }

        if (TTE_IS_REF(ttep))  {
                rm = P_REF;
        }
        if (TTE_IS_MOD(ttep))  {
                rm |= P_MOD;
        }

        if (rm == 0) {
                return;
        }

        sz = TTE_CSZ(ttep);
        if (sfmmup != NULL && sfmmup->sfmmu_rmstat) {
                int i;
                caddr_t vaddr = addr;

                for (i = 0; i < TTEPAGES(sz); i++, vaddr += MMU_PAGESIZE) {
                        hat_setstat(sfmmup->sfmmu_as, vaddr, MMU_PAGESIZE, rm);
                }

        }

        /*
         * XXX I want to use cas to update nrm bits but they
         * currently belong in common/vm and not in hat where
         * they should be.
         * The nrm bits are protected by the same mutex as
         * the one that protects the page's mapping list.
         */
        if (!pp)
                return;
        ASSERT(sfmmu_mlist_held(pp));
        /*
         * If the tte is for a large page, we need to sync all the
         * pages covered by the tte.
         */
        if (sz != TTE8K) {
                ASSERT(pp->p_szc != 0);
                pp = PP_GROUPLEADER(pp, sz);
                ASSERT(sfmmu_mlist_held(pp));
        }

        /* Get number of pages from tte size. */
        npgs = TTEPAGES(sz);

        do {
                ASSERT(pp);
                ASSERT(sfmmu_mlist_held(pp));
                if (((rm & P_REF) != 0 && !PP_ISREF(pp)) ||
                    ((rm & P_MOD) != 0 && !PP_ISMOD(pp)))
                        hat_page_setattr(pp, rm);

                /*
                 * Are we done? If not, we must have a large mapping.
                 * For large mappings we need to sync the rest of the pages
                 * covered by this tte; goto the next page.
                 */
        } while (--npgs > 0 && (pp = PP_PAGENEXT(pp)));
}

/*
 * Execute pre-callback handler of each pa_hment linked to pp
 *
 * Inputs:
 *   flag: either HAT_PRESUSPEND or HAT_SUSPEND.
 *   capture_cpus: pointer to return value (below)
 *
 * Returns:
 *   Propagates the subsystem callback return values back to the caller;
 *   returns 0 on success.  If capture_cpus is non-NULL, the value returned
 *   is zero if all of the pa_hments are of a type that do not require
 *   capturing CPUs prior to suspending the mapping, else it is 1.
 */
static int
hat_pageprocess_precallbacks(struct page *pp, uint_t flag, int *capture_cpus)
{
        struct sf_hment *sfhmep;
        struct pa_hment *pahmep;
        int (*f)(caddr_t, uint_t, uint_t, void *);
        int             ret;
        id_t            id;
        int             locked = 0;
        kmutex_t        *pml;

        ASSERT(PAGE_EXCL(pp));
        if (!sfmmu_mlist_held(pp)) {
                pml = sfmmu_mlist_enter(pp);
                locked = 1;
        }

        if (capture_cpus)
                *capture_cpus = 0;

top:
        for (sfhmep = pp->p_mapping; sfhmep; sfhmep = sfhmep->hme_next) {
                /*
                 * skip sf_hments corresponding to VA<->PA mappings;
                 * for pa_hment's, hme_tte.ll is zero
                 */
                if (!IS_PAHME(sfhmep))
                        continue;

                pahmep = sfhmep->hme_data;
                ASSERT(pahmep != NULL);

                /*
                 * skip if pre-handler has been called earlier in this loop
                 */
                if (pahmep->flags & flag)
                        continue;

                id = pahmep->cb_id;
                ASSERT(id >= (id_t)0 && id < sfmmu_cb_nextid);
                if (capture_cpus && sfmmu_cb_table[id].capture_cpus != 0)
                        *capture_cpus = 1;
                if ((f = sfmmu_cb_table[id].prehandler) == NULL) {
                        pahmep->flags |= flag;
                        continue;
                }

                /*
                 * Drop the mapping list lock to avoid locking order issues.
                 */
                if (locked)
                        sfmmu_mlist_exit(pml);

                ret = f(pahmep->addr, pahmep->len, flag, pahmep->pvt);
                if (ret != 0)
                        return (ret);   /* caller must do the cleanup */

                if (locked) {
                        pml = sfmmu_mlist_enter(pp);
                        pahmep->flags |= flag;
                        goto top;
                }

                pahmep->flags |= flag;
        }

        if (locked)
                sfmmu_mlist_exit(pml);

        return (0);
}

/*
 * Execute post-callback handler of each pa_hment linked to pp
 *
 * Same overall assumptions and restrictions apply as for
 * hat_pageprocess_precallbacks().
 */
static void
hat_pageprocess_postcallbacks(struct page *pp, uint_t flag)
{
        pfn_t pgpfn = pp->p_pagenum;
        pfn_t pgmask = btop(page_get_pagesize(pp->p_szc)) - 1;
        pfn_t newpfn;
        struct sf_hment *sfhmep;
        struct pa_hment *pahmep;
        int (*f)(caddr_t, uint_t, uint_t, void *, pfn_t);
        id_t    id;
        int     locked = 0;
        kmutex_t *pml;

        ASSERT(PAGE_EXCL(pp));
        if (!sfmmu_mlist_held(pp)) {
                pml = sfmmu_mlist_enter(pp);
                locked = 1;
        }

top:
        for (sfhmep = pp->p_mapping; sfhmep; sfhmep = sfhmep->hme_next) {
                /*
                 * skip sf_hments corresponding to VA<->PA mappings;
                 * for pa_hment's, hme_tte.ll is zero
                 */
                if (!IS_PAHME(sfhmep))
                        continue;

                pahmep = sfhmep->hme_data;
                ASSERT(pahmep != NULL);

                if ((pahmep->flags & flag) == 0)
                        continue;

                pahmep->flags &= ~flag;

                id = pahmep->cb_id;
                ASSERT(id >= (id_t)0 && id < sfmmu_cb_nextid);
                if ((f = sfmmu_cb_table[id].posthandler) == NULL)
                        continue;

                /*
                 * Convert the base page PFN into the constituent PFN
                 * which is needed by the callback handler.
                 */
                newpfn = pgpfn | (btop((uintptr_t)pahmep->addr) & pgmask);

                /*
                 * Drop the mapping list lock to avoid locking order issues.
                 */
                if (locked)
                        sfmmu_mlist_exit(pml);

                if (f(pahmep->addr, pahmep->len, flag, pahmep->pvt, newpfn)
                    != 0)
                        panic("sfmmu: posthandler failed");

                if (locked) {
                        pml = sfmmu_mlist_enter(pp);
                        goto top;
                }
        }

        if (locked)
                sfmmu_mlist_exit(pml);
}

/*
 * Suspend locked kernel mapping
 */
void
hat_pagesuspend(struct page *pp)
{
        struct sf_hment *sfhmep;
        sfmmu_t *sfmmup;
        tte_t tte, ttemod;
        struct hme_blk *hmeblkp;
        caddr_t addr;
        int index, cons;
        cpuset_t cpuset;

        ASSERT(PAGE_EXCL(pp));
        ASSERT(sfmmu_mlist_held(pp));

        mutex_enter(&kpr_suspendlock);

        /*
         * We're about to suspend a kernel mapping so mark this thread as
         * non-traceable by DTrace. This prevents us from running into issues
         * with probe context trying to touch a suspended page
         * in the relocation codepath itself.
         */
        curthread->t_flag |= T_DONTDTRACE;

        index = PP_MAPINDEX(pp);
        cons = TTE8K;

retry:
        for (sfhmep = pp->p_mapping; sfhmep; sfhmep = sfhmep->hme_next) {

                if (IS_PAHME(sfhmep))
                        continue;

                if (get_hblk_ttesz(sfmmu_hmetohblk(sfhmep)) != cons)
                        continue;

                /*
                 * Loop until we successfully set the suspend bit in
                 * the TTE.
                 */
again:
                sfmmu_copytte(&sfhmep->hme_tte, &tte);
                ASSERT(TTE_IS_VALID(&tte));

                ttemod = tte;
                TTE_SET_SUSPEND(&ttemod);
                if (sfmmu_modifytte_try(&tte, &ttemod,
                    &sfhmep->hme_tte) < 0)
                        goto again;

                /*
                 * Invalidate TSB entry
                 */
                hmeblkp = sfmmu_hmetohblk(sfhmep);

                sfmmup = hblktosfmmu(hmeblkp);
                ASSERT(sfmmup == ksfmmup);
                ASSERT(!hmeblkp->hblk_shared);

                addr = tte_to_vaddr(hmeblkp, tte);

                /*
                 * No need to make sure that the TSB for this sfmmu is
                 * not being relocated since it is ksfmmup and thus it
                 * will never be relocated.
                 */
                SFMMU_UNLOAD_TSB(addr, sfmmup, hmeblkp, 0);

                /*
                 * Update xcall stats
                 */
                cpuset = cpu_ready_set;
                CPUSET_DEL(cpuset, CPU->cpu_id);

                /* LINTED: constant in conditional context */
                SFMMU_XCALL_STATS(ksfmmup);

                /*
                 * Flush TLB entry on remote CPU's
                 */
                xt_some(cpuset, vtag_flushpage_tl1, (uint64_t)addr,
                    (uint64_t)ksfmmup);
                xt_sync(cpuset);

                /*
                 * Flush TLB entry on local CPU
                 */
                vtag_flushpage(addr, (uint64_t)ksfmmup);
        }

        while (index != 0) {
                index = index >> 1;
                if (index != 0)
                        cons++;
                if (index & 0x1) {
                        pp = PP_GROUPLEADER(pp, cons);
                        goto retry;
                }
        }
}

#ifdef  DEBUG

#define N_PRLE  1024
struct prle {
        page_t *targ;
        page_t *repl;
        int status;
        int pausecpus;
        hrtime_t whence;
};

static struct prle page_relocate_log[N_PRLE];
static int prl_entry;
static kmutex_t prl_mutex;

#define PAGE_RELOCATE_LOG(t, r, s, p)                                   \
        mutex_enter(&prl_mutex);                                        \
        page_relocate_log[prl_entry].targ = *(t);                       \
        page_relocate_log[prl_entry].repl = *(r);                       \
        page_relocate_log[prl_entry].status = (s);                      \
        page_relocate_log[prl_entry].pausecpus = (p);                   \
        page_relocate_log[prl_entry].whence = gethrtime();              \
        prl_entry = (prl_entry == (N_PRLE - 1))? 0 : prl_entry + 1;     \
        mutex_exit(&prl_mutex);

#else   /* !DEBUG */
#define PAGE_RELOCATE_LOG(t, r, s, p)
#endif

/*
 * Core Kernel Page Relocation Algorithm
 *
 * Input:
 *
 * target :     constituent pages are SE_EXCL locked.
 * replacement: constituent pages are SE_EXCL locked.
 *
 * Output:
 *
 * nrelocp:     number of pages relocated
 */
int
hat_page_relocate(page_t **target, page_t **replacement, spgcnt_t *nrelocp)
{
        page_t          *targ, *repl;
        page_t          *tpp, *rpp;
        kmutex_t        *low, *high;
        spgcnt_t        npages, i;
        page_t          *pl = NULL;
        int             old_pil;
        cpuset_t        cpuset;
        int             cap_cpus;
        int             ret;
#ifdef VAC
        int             cflags = 0;
#endif

        if (!kcage_on || PP_ISNORELOC(*target)) {
                PAGE_RELOCATE_LOG(target, replacement, EAGAIN, -1);
                return (EAGAIN);
        }

        mutex_enter(&kpr_mutex);
        kreloc_thread = curthread;

        targ = *target;
        repl = *replacement;
        ASSERT(repl != NULL);
        ASSERT(targ->p_szc == repl->p_szc);

        npages = page_get_pagecnt(targ->p_szc);

        /*
         * unload VA<->PA mappings that are not locked
         */
        tpp = targ;
        for (i = 0; i < npages; i++) {
                (void) hat_pageunload(tpp, SFMMU_KERNEL_RELOC);
                tpp++;
        }

        /*
         * Do "presuspend" callbacks, in a context from which we can still
         * block as needed. Note that we don't hold the mapping list lock
         * of "targ" at this point due to potential locking order issues;
         * we assume that between the hat_pageunload() above and holding
         * the SE_EXCL lock that the mapping list *cannot* change at this
         * point.
         */
        ret = hat_pageprocess_precallbacks(targ, HAT_PRESUSPEND, &cap_cpus);
        if (ret != 0) {
                /*
                 * EIO translates to fatal error, for all others cleanup
                 * and return EAGAIN.
                 */
                ASSERT(ret != EIO);
                hat_pageprocess_postcallbacks(targ, HAT_POSTUNSUSPEND);
                PAGE_RELOCATE_LOG(target, replacement, ret, -1);
                kreloc_thread = NULL;
                mutex_exit(&kpr_mutex);
                return (EAGAIN);
        }

        /*
         * acquire p_mapping list lock for both the target and replacement
         * root pages.
         *
         * low and high refer to the need to grab the mlist locks in a
         * specific order in order to prevent race conditions.  Thus the
         * lower lock must be grabbed before the higher lock.
         *
         * This will block hat_unload's accessing p_mapping list.  Since
         * we have SE_EXCL lock, hat_memload and hat_pageunload will be
         * blocked.  Thus, no one else will be accessing the p_mapping list
         * while we suspend and reload the locked mapping below.
         */
        tpp = targ;
        rpp = repl;
        sfmmu_mlist_reloc_enter(tpp, rpp, &low, &high);

        kpreempt_disable();

        /*
         * We raise our PIL to 13 so that we don't get captured by
         * another CPU or pinned by an interrupt thread.  We can't go to
         * PIL 14 since the nexus driver(s) may need to interrupt at
         * that level in the case of IOMMU pseudo mappings.
         */
        cpuset = cpu_ready_set;
        CPUSET_DEL(cpuset, CPU->cpu_id);
        if (!cap_cpus || CPUSET_ISNULL(cpuset)) {
                old_pil = splr(XCALL_PIL);
        } else {
                old_pil = -1;
                xc_attention(cpuset);
        }
        ASSERT(getpil() == XCALL_PIL);

        /*
         * Now do suspend callbacks. In the case of an IOMMU mapping
         * this will suspend all DMA activity to the page while it is
         * being relocated. Since we are well above LOCK_LEVEL and CPUs
         * may be captured at this point we should have acquired any needed
         * locks in the presuspend callback.
         */
        ret = hat_pageprocess_precallbacks(targ, HAT_SUSPEND, NULL);
        if (ret != 0) {
                repl = targ;
                goto suspend_fail;
        }

        /*
         * Raise the PIL yet again, this time to block all high-level
         * interrupts on this CPU. This is necessary to prevent an
         * interrupt routine from pinning the thread which holds the
         * mapping suspended and then touching the suspended page.
         *
         * Once the page is suspended we also need to be careful to
         * avoid calling any functions which touch any seg_kmem memory
         * since that memory may be backed by the very page we are
         * relocating in here!
         */
        hat_pagesuspend(targ);

        /*
         * Now that we are confident everybody has stopped using this page,
         * copy the page contents.  Note we use a physical copy to prevent
         * locking issues and to avoid fpRAS because we can't handle it in
         * this context.
         */
        for (i = 0; i < npages; i++, tpp++, rpp++) {
#ifdef VAC
                /*
                 * If the replacement has a different vcolor than
                 * the one being replacd, we need to handle VAC
                 * consistency for it just as we were setting up
                 * a new mapping to it.
                 */
                if ((PP_GET_VCOLOR(rpp) != NO_VCOLOR) &&
                    (tpp->p_vcolor != rpp->p_vcolor) &&
                    !CacheColor_IsFlushed(cflags, PP_GET_VCOLOR(rpp))) {
                        CacheColor_SetFlushed(cflags, PP_GET_VCOLOR(rpp));
                        sfmmu_cache_flushcolor(PP_GET_VCOLOR(rpp),
                            rpp->p_pagenum);
                }
#endif
                /*
                 * Copy the contents of the page.
                 */
                ppcopy_kernel(tpp, rpp);
        }

        tpp = targ;
        rpp = repl;
        for (i = 0; i < npages; i++, tpp++, rpp++) {
                /*
                 * Copy attributes.  VAC consistency was handled above,
                 * if required.
                 */
                rpp->p_nrm = tpp->p_nrm;
                tpp->p_nrm = 0;
                rpp->p_index = tpp->p_index;
                tpp->p_index = 0;
#ifdef VAC
                rpp->p_vcolor = tpp->p_vcolor;
#endif
        }

        /*
         * First, unsuspend the page, if we set the suspend bit, and transfer
         * the mapping list from the target page to the replacement page.
         * Next process postcallbacks; since pa_hment's are linked only to the
         * p_mapping list of root page, we don't iterate over the constituent
         * pages.
         */
        hat_pagereload(targ, repl);

suspend_fail:
        hat_pageprocess_postcallbacks(repl, HAT_UNSUSPEND);

        /*
         * Now lower our PIL and release any captured CPUs since we
         * are out of the "danger zone".  After this it will again be
         * safe to acquire adaptive mutex locks, or to drop them...
         */
        if (old_pil != -1) {
                splx(old_pil);
        } else {
                xc_dismissed(cpuset);
        }

        kpreempt_enable();

        sfmmu_mlist_reloc_exit(low, high);

        /*
         * Postsuspend callbacks should drop any locks held across
         * the suspend callbacks.  As before, we don't hold the mapping
         * list lock at this point.. our assumption is that the mapping
         * list still can't change due to our holding SE_EXCL lock and
         * there being no unlocked mappings left. Hence the restriction
         * on calling context to hat_delete_callback()
         */
        hat_pageprocess_postcallbacks(repl, HAT_POSTUNSUSPEND);
        if (ret != 0) {
                /*
                 * The second presuspend call failed: we got here through
                 * the suspend_fail label above.
                 */
                ASSERT(ret != EIO);
                PAGE_RELOCATE_LOG(target, replacement, ret, cap_cpus);
                kreloc_thread = NULL;
                mutex_exit(&kpr_mutex);
                return (EAGAIN);
        }

        /*
         * Now that we're out of the performance critical section we can
         * take care of updating the hash table, since we still
         * hold all the pages locked SE_EXCL at this point we
         * needn't worry about things changing out from under us.
         */
        tpp = targ;
        rpp = repl;
        for (i = 0; i < npages; i++, tpp++, rpp++) {

                /*
                 * replace targ with replacement in page_hash table
                 */
                targ = tpp;
                page_relocate_hash(rpp, targ);

                /*
                 * concatenate target; caller of platform_page_relocate()
                 * expects target to be concatenated after returning.
                 */
                ASSERT(targ->p_next == targ);
                ASSERT(targ->p_prev == targ);
                page_list_concat(&pl, &targ);
        }

        ASSERT(*target == pl);
        *nrelocp = npages;
        PAGE_RELOCATE_LOG(target, replacement, 0, cap_cpus);
        kreloc_thread = NULL;
        mutex_exit(&kpr_mutex);
        return (0);
}

/*
 * Called when stray pa_hments are found attached to a page which is
 * being freed.  Notify the subsystem which attached the pa_hment of
 * the error if it registered a suitable handler, else panic.
 */
static void
sfmmu_pahment_leaked(struct pa_hment *pahmep)
{
        id_t cb_id = pahmep->cb_id;

        ASSERT(cb_id >= (id_t)0 && cb_id < sfmmu_cb_nextid);
        if (sfmmu_cb_table[cb_id].errhandler != NULL) {
                if (sfmmu_cb_table[cb_id].errhandler(pahmep->addr, pahmep->len,
                    HAT_CB_ERR_LEAKED, pahmep->pvt) == 0)
                        return;         /* non-fatal */
        }
        panic("pa_hment leaked: 0x%p", (void *)pahmep);
}

/*
 * Remove all mappings to page 'pp'.
 */
int
hat_pageunload(struct page *pp, uint_t forceflag)
{
        struct page *origpp = pp;
        struct sf_hment *sfhme, *tmphme;
        struct hme_blk *hmeblkp;
        kmutex_t *pml;
#ifdef VAC
        kmutex_t *pmtx;
#endif
        cpuset_t cpuset, tset;
        int index, cons;
        int pa_hments;

        ASSERT(PAGE_EXCL(pp));

        tmphme = NULL;
        pa_hments = 0;
        CPUSET_ZERO(cpuset);

        pml = sfmmu_mlist_enter(pp);

#ifdef VAC
        if (pp->p_kpmref)
                sfmmu_kpm_pageunload(pp);
        ASSERT(!PP_ISMAPPED_KPM(pp));
#endif
        /*
         * Clear vpm reference. Since the page is exclusively locked
         * vpm cannot be referencing it.
         */
        if (vpm_enable) {
                pp->p_vpmref = 0;
        }

        index = PP_MAPINDEX(pp);
        cons = TTE8K;
retry:
        for (sfhme = pp->p_mapping; sfhme; sfhme = tmphme) {
                tmphme = sfhme->hme_next;

                if (IS_PAHME(sfhme)) {
                        ASSERT(sfhme->hme_data != NULL);
                        pa_hments++;
                        continue;
                }

                hmeblkp = sfmmu_hmetohblk(sfhme);

                /*
                 * If there are kernel mappings don't unload them, they will
                 * be suspended.
                 */
                if (forceflag == SFMMU_KERNEL_RELOC && hmeblkp->hblk_lckcnt &&
                    hmeblkp->hblk_tag.htag_id == ksfmmup)
                        continue;

                tset = sfmmu_pageunload(pp, sfhme, cons);
                CPUSET_OR(cpuset, tset);
        }

        while (index != 0) {
                index = index >> 1;
                if (index != 0)
                        cons++;
                if (index & 0x1) {
                        /* Go to leading page */
                        pp = PP_GROUPLEADER(pp, cons);
                        ASSERT(sfmmu_mlist_held(pp));
                        goto retry;
                }
        }

        /*
         * cpuset may be empty if the page was only mapped by segkpm,
         * in which case we won't actually cross-trap.
         */
        xt_sync(cpuset);

        /*
         * The page should have no mappings at this point, unless
         * we were called from hat_page_relocate() in which case we
         * leave the locked mappings which will be suspended later.
         */
        ASSERT(!PP_ISMAPPED(origpp) || pa_hments ||
            (forceflag == SFMMU_KERNEL_RELOC));

#ifdef VAC
        if (PP_ISTNC(pp)) {
                if (cons == TTE8K) {
                        pmtx = sfmmu_page_enter(pp);
                        PP_CLRTNC(pp);
                        sfmmu_page_exit(pmtx);
                } else {
                        conv_tnc(pp, cons);
                }
        }
#endif  /* VAC */

        if (pa_hments && forceflag != SFMMU_KERNEL_RELOC) {
                /*
                 * Unlink any pa_hments and free them, calling back
                 * the responsible subsystem to notify it of the error.
                 * This can occur in situations such as drivers leaking
                 * DMA handles: naughty, but common enough that we'd like
                 * to keep the system running rather than bringing it
                 * down with an obscure error like "pa_hment leaked"
                 * which doesn't aid the user in debugging their driver.
                 */
                for (sfhme = pp->p_mapping; sfhme; sfhme = tmphme) {
                        tmphme = sfhme->hme_next;
                        if (IS_PAHME(sfhme)) {
                                struct pa_hment *pahmep = sfhme->hme_data;
                                sfmmu_pahment_leaked(pahmep);
                                HME_SUB(sfhme, pp);
                                kmem_cache_free(pa_hment_cache, pahmep);
                        }
                }

                ASSERT(!PP_ISMAPPED(origpp));
        }

        sfmmu_mlist_exit(pml);

        return (0);
}

cpuset_t
sfmmu_pageunload(page_t *pp, struct sf_hment *sfhme, int cons)
{
        struct hme_blk *hmeblkp;
        sfmmu_t *sfmmup;
        tte_t tte, ttemod;
#ifdef DEBUG
        tte_t orig_old;
#endif /* DEBUG */
        caddr_t addr;
        int ttesz;
        int ret;
        cpuset_t cpuset;

        ASSERT(pp != NULL);
        ASSERT(sfmmu_mlist_held(pp));
        ASSERT(!PP_ISKAS(pp));

        CPUSET_ZERO(cpuset);

        hmeblkp = sfmmu_hmetohblk(sfhme);

readtte:
        sfmmu_copytte(&sfhme->hme_tte, &tte);
        if (TTE_IS_VALID(&tte)) {
                sfmmup = hblktosfmmu(hmeblkp);
                ttesz = get_hblk_ttesz(hmeblkp);
                /*
                 * Only unload mappings of 'cons' size.
                 */
                if (ttesz != cons)
                        return (cpuset);

                /*
                 * Note that we have p_mapping lock, but no hash lock here.
                 * hblk_unload() has to have both hash lock AND p_mapping
                 * lock before it tries to modify tte. So, the tte could
                 * not become invalid in the sfmmu_modifytte_try() below.
                 */
                ttemod = tte;
#ifdef DEBUG
                orig_old = tte;
#endif /* DEBUG */

                TTE_SET_INVALID(&ttemod);
                ret = sfmmu_modifytte_try(&tte, &ttemod, &sfhme->hme_tte);
                if (ret < 0) {
#ifdef DEBUG
                        /* only R/M bits can change. */
                        chk_tte(&orig_old, &tte, &ttemod, hmeblkp);
#endif /* DEBUG */
                        goto readtte;
                }

                if (ret == 0) {
                        panic("pageunload: cas failed?");
                }

                addr = tte_to_vaddr(hmeblkp, tte);

                if (hmeblkp->hblk_shared) {
                        sf_srd_t *srdp = (sf_srd_t *)sfmmup;
                        uint_t rid = hmeblkp->hblk_tag.htag_rid;
                        sf_region_t *rgnp;
                        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                        ASSERT(srdp != NULL);
                        rgnp = srdp->srd_hmergnp[rid];
                        SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp, rgnp, rid);
                        cpuset = sfmmu_rgntlb_demap(addr, rgnp, hmeblkp, 1);
                        sfmmu_ttesync(NULL, addr, &tte, pp);
                        ASSERT(rgnp->rgn_ttecnt[ttesz] > 0);
                        atomic_dec_ulong(&rgnp->rgn_ttecnt[ttesz]);
                } else {
                        sfmmu_ttesync(sfmmup, addr, &tte, pp);
                        atomic_dec_ulong(&sfmmup->sfmmu_ttecnt[ttesz]);

                        /*
                         * We need to flush the page from the virtual cache
                         * in order to prevent a virtual cache alias
                         * inconsistency. The particular scenario we need
                         * to worry about is:
                         * Given:  va1 and va2 are two virtual address that
                         * alias and will map the same physical address.
                         * 1.   mapping exists from va1 to pa and data has
                         *      been read into the cache.
                         * 2.   unload va1.
                         * 3.   load va2 and modify data using va2.
                         * 4    unload va2.
                         * 5.   load va1 and reference data.  Unless we flush
                         *      the data cache when we unload we will get
                         *      stale data.
                         * This scenario is taken care of by using virtual
                         * page coloring.
                         */
                        if (sfmmup->sfmmu_ismhat) {
                                /*
                                 * Flush TSBs, TLBs and caches
                                 * of every process
                                 * sharing this ism segment.
                                 */
                                sfmmu_hat_lock_all();
                                mutex_enter(&ism_mlist_lock);
                                kpreempt_disable();
                                sfmmu_ismtlbcache_demap(addr, sfmmup, hmeblkp,
                                    pp->p_pagenum, CACHE_NO_FLUSH);
                                kpreempt_enable();
                                mutex_exit(&ism_mlist_lock);
                                sfmmu_hat_unlock_all();
                                cpuset = cpu_ready_set;
                        } else {
                                sfmmu_tlb_demap(addr, sfmmup, hmeblkp, 0, 0);
                                cpuset = sfmmup->sfmmu_cpusran;
                        }
                }

                /*
                 * Hme_sub has to run after ttesync() and a_rss update.
                 * See hblk_unload().
                 */
                HME_SUB(sfhme, pp);
                membar_stst();

                /*
                 * We can not make ASSERT(hmeblkp->hblk_hmecnt <= NHMENTS)
                 * since pteload may have done a HME_ADD() right after
                 * we did the HME_SUB() above. Hmecnt is now maintained
                 * by cas only. no lock guranteed its value. The only
                 * gurantee we have is the hmecnt should not be less than
                 * what it should be so the hblk will not be taken away.
                 * It's also important that we decremented the hmecnt after
                 * we are done with hmeblkp so that this hmeblk won't be
                 * stolen.
                 */
                ASSERT(hmeblkp->hblk_hmecnt > 0);
                ASSERT(hmeblkp->hblk_vcnt > 0);
                atomic_dec_16(&hmeblkp->hblk_vcnt);
                atomic_dec_16(&hmeblkp->hblk_hmecnt);
                /*
                 * This is bug 4063182.
                 * XXX: fixme
                 * ASSERT(hmeblkp->hblk_hmecnt || hmeblkp->hblk_vcnt ||
                 *      !hmeblkp->hblk_lckcnt);
                 */
        } else {
                panic("invalid tte? pp %p &tte %p",
                    (void *)pp, (void *)&tte);
        }

        return (cpuset);
}

/*
 * While relocating a kernel page, this function will move the mappings
 * from tpp to dpp and modify any associated data with these mappings.
 * It also unsuspends the suspended kernel mapping.
 */
static void
hat_pagereload(struct page *tpp, struct page *dpp)
{
        struct sf_hment *sfhme;
        tte_t tte, ttemod;
        int index, cons;

        ASSERT(getpil() == PIL_MAX);
        ASSERT(sfmmu_mlist_held(tpp));
        ASSERT(sfmmu_mlist_held(dpp));

        index = PP_MAPINDEX(tpp);
        cons = TTE8K;

        /* Update real mappings to the page */
retry:
        for (sfhme = tpp->p_mapping; sfhme != NULL; sfhme = sfhme->hme_next) {
                if (IS_PAHME(sfhme))
                        continue;
                sfmmu_copytte(&sfhme->hme_tte, &tte);
                ttemod = tte;

                /*
                 * replace old pfn with new pfn in TTE
                 */
                PFN_TO_TTE(ttemod, dpp->p_pagenum);

                /*
                 * clear suspend bit
                 */
                ASSERT(TTE_IS_SUSPEND(&ttemod));
                TTE_CLR_SUSPEND(&ttemod);

                if (sfmmu_modifytte_try(&tte, &ttemod, &sfhme->hme_tte) < 0)
                        panic("hat_pagereload(): sfmmu_modifytte_try() failed");

                /*
                 * set hme_page point to new page
                 */
                sfhme->hme_page = dpp;
        }

        /*
         * move p_mapping list from old page to new page
         */
        dpp->p_mapping = tpp->p_mapping;
        tpp->p_mapping = NULL;
        dpp->p_share = tpp->p_share;
        tpp->p_share = 0;

        while (index != 0) {
                index = index >> 1;
                if (index != 0)
                        cons++;
                if (index & 0x1) {
                        tpp = PP_GROUPLEADER(tpp, cons);
                        dpp = PP_GROUPLEADER(dpp, cons);
                        goto retry;
                }
        }

        curthread->t_flag &= ~T_DONTDTRACE;
        mutex_exit(&kpr_suspendlock);
}

uint_t
hat_pagesync(struct page *pp, uint_t clearflag)
{
        struct sf_hment *sfhme, *tmphme = NULL;
        struct hme_blk *hmeblkp;
        kmutex_t *pml;
        cpuset_t cpuset, tset;
        int     index, cons;
        extern  ulong_t po_share;
        page_t  *save_pp = pp;
        int     stop_on_sh = 0;
        uint_t  shcnt;

        CPUSET_ZERO(cpuset);

        if (PP_ISRO(pp) && (clearflag & HAT_SYNC_STOPON_MOD)) {
                return (PP_GENERIC_ATTR(pp));
        }

        if ((clearflag & HAT_SYNC_ZERORM) == 0) {
                if ((clearflag & HAT_SYNC_STOPON_REF) && PP_ISREF(pp)) {
                        return (PP_GENERIC_ATTR(pp));
                }
                if ((clearflag & HAT_SYNC_STOPON_MOD) && PP_ISMOD(pp)) {
                        return (PP_GENERIC_ATTR(pp));
                }
                if (clearflag & HAT_SYNC_STOPON_SHARED) {
                        if (pp->p_share > po_share) {
                                hat_page_setattr(pp, P_REF);
                                return (PP_GENERIC_ATTR(pp));
                        }
                        stop_on_sh = 1;
                        shcnt = 0;
                }
        }

        clearflag &= ~HAT_SYNC_STOPON_SHARED;
        pml = sfmmu_mlist_enter(pp);
        index = PP_MAPINDEX(pp);
        cons = TTE8K;
retry:
        for (sfhme = pp->p_mapping; sfhme; sfhme = tmphme) {
                /*
                 * We need to save the next hment on the list since
                 * it is possible for pagesync to remove an invalid hment
                 * from the list.
                 */
                tmphme = sfhme->hme_next;
                if (IS_PAHME(sfhme))
                        continue;
                /*
                 * If we are looking for large mappings and this hme doesn't
                 * reach the range we are seeking, just ignore it.
                 */
                hmeblkp = sfmmu_hmetohblk(sfhme);

                if (hme_size(sfhme) < cons)
                        continue;

                if (stop_on_sh) {
                        if (hmeblkp->hblk_shared) {
                                sf_srd_t *srdp = hblktosrd(hmeblkp);
                                uint_t rid = hmeblkp->hblk_tag.htag_rid;
                                sf_region_t *rgnp;
                                ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                                ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                                ASSERT(srdp != NULL);
                                rgnp = srdp->srd_hmergnp[rid];
                                SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp,
                                    rgnp, rid);
                                shcnt += rgnp->rgn_refcnt;
                        } else {
                                shcnt++;
                        }
                        if (shcnt > po_share) {
                                /*
                                 * tell the pager to spare the page this time
                                 * around.
                                 */
                                hat_page_setattr(save_pp, P_REF);
                                index = 0;
                                break;
                        }
                }
                tset = sfmmu_pagesync(pp, sfhme,
                    clearflag & ~HAT_SYNC_STOPON_RM);
                CPUSET_OR(cpuset, tset);

                /*
                 * If clearflag is HAT_SYNC_DONTZERO, break out as soon
                 * as the "ref" or "mod" is set or share cnt exceeds po_share.
                 */
                if ((clearflag & ~HAT_SYNC_STOPON_RM) == HAT_SYNC_DONTZERO &&
                    (((clearflag & HAT_SYNC_STOPON_MOD) && PP_ISMOD(save_pp)) ||
                    ((clearflag & HAT_SYNC_STOPON_REF) && PP_ISREF(save_pp)))) {
                        index = 0;
                        break;
                }
        }

        while (index) {
                index = index >> 1;
                cons++;
                if (index & 0x1) {
                        /* Go to leading page */
                        pp = PP_GROUPLEADER(pp, cons);
                        goto retry;
                }
        }

        xt_sync(cpuset);
        sfmmu_mlist_exit(pml);
        return (PP_GENERIC_ATTR(save_pp));
}

/*
 * Get all the hardware dependent attributes for a page struct
 */
static cpuset_t
sfmmu_pagesync(struct page *pp, struct sf_hment *sfhme,
    uint_t clearflag)
{
        caddr_t addr;
        tte_t tte, ttemod;
        struct hme_blk *hmeblkp;
        int ret;
        sfmmu_t *sfmmup;
        cpuset_t cpuset;

        ASSERT(pp != NULL);
        ASSERT(sfmmu_mlist_held(pp));
        ASSERT((clearflag == HAT_SYNC_DONTZERO) ||
            (clearflag == HAT_SYNC_ZERORM));

        SFMMU_STAT(sf_pagesync);

        CPUSET_ZERO(cpuset);

sfmmu_pagesync_retry:

        sfmmu_copytte(&sfhme->hme_tte, &tte);
        if (TTE_IS_VALID(&tte)) {
                hmeblkp = sfmmu_hmetohblk(sfhme);
                sfmmup = hblktosfmmu(hmeblkp);
                addr = tte_to_vaddr(hmeblkp, tte);
                if (clearflag == HAT_SYNC_ZERORM) {
                        ttemod = tte;
                        TTE_CLR_RM(&ttemod);
                        ret = sfmmu_modifytte_try(&tte, &ttemod,
                            &sfhme->hme_tte);
                        if (ret < 0) {
                                /*
                                 * cas failed and the new value is not what
                                 * we want.
                                 */
                                goto sfmmu_pagesync_retry;
                        }

                        if (ret > 0) {
                                /* we win the cas */
                                if (hmeblkp->hblk_shared) {
                                        sf_srd_t *srdp = (sf_srd_t *)sfmmup;
                                        uint_t rid =
                                            hmeblkp->hblk_tag.htag_rid;
                                        sf_region_t *rgnp;
                                        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                                        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                                        ASSERT(srdp != NULL);
                                        rgnp = srdp->srd_hmergnp[rid];
                                        SFMMU_VALIDATE_SHAREDHBLK(hmeblkp,
                                            srdp, rgnp, rid);
                                        cpuset = sfmmu_rgntlb_demap(addr,
                                            rgnp, hmeblkp, 1);
                                } else {
                                        sfmmu_tlb_demap(addr, sfmmup, hmeblkp,
                                            0, 0);
                                        cpuset = sfmmup->sfmmu_cpusran;
                                }
                        }
                }
                sfmmu_ttesync(hmeblkp->hblk_shared ? NULL : sfmmup, addr,
                    &tte, pp);
        }
        return (cpuset);
}

/*
 * Remove write permission from a mappings to a page, so that
 * we can detect the next modification of it. This requires modifying
 * the TTE then invalidating (demap) any TLB entry using that TTE.
 * This code is similar to sfmmu_pagesync().
 */
static cpuset_t
sfmmu_pageclrwrt(struct page *pp, struct sf_hment *sfhme)
{
        caddr_t addr;
        tte_t tte;
        tte_t ttemod;
        struct hme_blk *hmeblkp;
        int ret;
        sfmmu_t *sfmmup;
        cpuset_t cpuset;

        ASSERT(pp != NULL);
        ASSERT(sfmmu_mlist_held(pp));

        CPUSET_ZERO(cpuset);
        SFMMU_STAT(sf_clrwrt);

retry:

        sfmmu_copytte(&sfhme->hme_tte, &tte);
        if (TTE_IS_VALID(&tte) && TTE_IS_WRITABLE(&tte)) {
                hmeblkp = sfmmu_hmetohblk(sfhme);
                sfmmup = hblktosfmmu(hmeblkp);
                addr = tte_to_vaddr(hmeblkp, tte);

                ttemod = tte;
                TTE_CLR_WRT(&ttemod);
                TTE_CLR_MOD(&ttemod);
                ret = sfmmu_modifytte_try(&tte, &ttemod, &sfhme->hme_tte);

                /*
                 * if cas failed and the new value is not what
                 * we want retry
                 */
                if (ret < 0)
                        goto retry;

                /* we win the cas */
                if (ret > 0) {
                        if (hmeblkp->hblk_shared) {
                                sf_srd_t *srdp = (sf_srd_t *)sfmmup;
                                uint_t rid = hmeblkp->hblk_tag.htag_rid;
                                sf_region_t *rgnp;
                                ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                                ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                                ASSERT(srdp != NULL);
                                rgnp = srdp->srd_hmergnp[rid];
                                SFMMU_VALIDATE_SHAREDHBLK(hmeblkp,
                                    srdp, rgnp, rid);
                                cpuset = sfmmu_rgntlb_demap(addr,
                                    rgnp, hmeblkp, 1);
                        } else {
                                sfmmu_tlb_demap(addr, sfmmup, hmeblkp, 0, 0);
                                cpuset = sfmmup->sfmmu_cpusran;
                        }
                }
        }

        return (cpuset);
}

/*
 * Walk all mappings of a page, removing write permission and clearing the
 * ref/mod bits. This code is similar to hat_pagesync()
 */
static void
hat_page_clrwrt(page_t *pp)
{
        struct sf_hment *sfhme;
        struct sf_hment *tmphme = NULL;
        kmutex_t *pml;
        cpuset_t cpuset;
        cpuset_t tset;
        int     index;
        int      cons;

        CPUSET_ZERO(cpuset);

        pml = sfmmu_mlist_enter(pp);
        index = PP_MAPINDEX(pp);
        cons = TTE8K;
retry:
        for (sfhme = pp->p_mapping; sfhme; sfhme = tmphme) {
                tmphme = sfhme->hme_next;

                /*
                 * If we are looking for large mappings and this hme doesn't
                 * reach the range we are seeking, just ignore its.
                 */

                if (hme_size(sfhme) < cons)
                        continue;

                tset = sfmmu_pageclrwrt(pp, sfhme);
                CPUSET_OR(cpuset, tset);
        }

        while (index) {
                index = index >> 1;
                cons++;
                if (index & 0x1) {
                        /* Go to leading page */
                        pp = PP_GROUPLEADER(pp, cons);
                        goto retry;
                }
        }

        xt_sync(cpuset);
        sfmmu_mlist_exit(pml);
}

/*
 * Set the given REF/MOD/RO bits for the given page.
 * For a vnode with a sorted v_pages list, we need to change
 * the attributes and the v_pages list together under page_vnode_mutex.
 */
void
hat_page_setattr(page_t *pp, uint_t flag)
{
        vnode_t         *vp = pp->p_vnode;
        page_t          **listp;
        kmutex_t        *pmtx;
        kmutex_t        *vphm = NULL;
        int             noshuffle;

        noshuffle = flag & P_NSH;
        flag &= ~P_NSH;

        ASSERT(!(flag & ~(P_MOD | P_REF | P_RO)));

        /*
         * nothing to do if attribute already set
         */
        if ((pp->p_nrm & flag) == flag)
                return;

        if ((flag & P_MOD) != 0 && vp != NULL && IS_VMODSORT(vp) &&
            !noshuffle) {
                vphm = page_vnode_mutex(vp);
                mutex_enter(vphm);
        }

        pmtx = sfmmu_page_enter(pp);
        pp->p_nrm |= flag;
        sfmmu_page_exit(pmtx);

        if (vphm != NULL) {
                /*
                 * Some File Systems examine v_pages for NULL w/o
                 * grabbing the vphm mutex. Must not let it become NULL when
                 * pp is the only page on the list.
                 */
                if (pp->p_vpnext != pp) {
                        page_vpsub(&vp->v_pages, pp);
                        if (vp->v_pages != NULL)
                                listp = &vp->v_pages->p_vpprev->p_vpnext;
                        else
                                listp = &vp->v_pages;
                        page_vpadd(listp, pp);
                }
                mutex_exit(vphm);
        }
}

void
hat_page_clrattr(page_t *pp, uint_t flag)
{
        vnode_t         *vp = pp->p_vnode;
        kmutex_t        *pmtx;

        ASSERT(!(flag & ~(P_MOD | P_REF | P_RO)));

        pmtx = sfmmu_page_enter(pp);

        /*
         * Caller is expected to hold page's io lock for VMODSORT to work
         * correctly with pvn_vplist_dirty() and pvn_getdirty() when mod
         * bit is cleared.
         * We don't have assert to avoid tripping some existing third party
         * code. The dirty page is moved back to top of the v_page list
         * after IO is done in pvn_write_done().
         */
        pp->p_nrm &= ~flag;
        sfmmu_page_exit(pmtx);

        if ((flag & P_MOD) != 0 && vp != NULL && IS_VMODSORT(vp)) {

                /*
                 * VMODSORT works by removing write permissions and getting
                 * a fault when a page is made dirty. At this point
                 * we need to remove write permission from all mappings
                 * to this page.
                 */
                hat_page_clrwrt(pp);
        }
}

uint_t
hat_page_getattr(page_t *pp, uint_t flag)
{
        ASSERT(!(flag & ~(P_MOD | P_REF | P_RO)));
        return ((uint_t)(pp->p_nrm & flag));
}

/*
 * DEBUG kernels: verify that a kernel va<->pa translation
 * is safe by checking the underlying page_t is in a page
 * relocation-safe state.
 */
#ifdef  DEBUG
void
sfmmu_check_kpfn(pfn_t pfn)
{
        page_t *pp;
        int index, cons;

        if (hat_check_vtop == 0)
                return;

        if (kvseg.s_base == NULL || panicstr)
                return;

        pp = page_numtopp_nolock(pfn);
        if (!pp)
                return;

        if (PAGE_LOCKED(pp) || PP_ISNORELOC(pp))
                return;

        /*
         * Handed a large kernel page, we dig up the root page since we
         * know the root page might have the lock also.
         */
        if (pp->p_szc != 0) {
                index = PP_MAPINDEX(pp);
                cons = TTE8K;
again:
                while (index != 0) {
                        index >>= 1;
                        if (index != 0)
                                cons++;
                        if (index & 0x1) {
                                pp = PP_GROUPLEADER(pp, cons);
                                goto again;
                        }
                }
        }

        if (PAGE_LOCKED(pp) || PP_ISNORELOC(pp))
                return;

        /*
         * Pages need to be locked or allocated "permanent" (either from
         * static_arena arena or explicitly setting PG_NORELOC when calling
         * page_create_va()) for VA->PA translations to be valid.
         */
        if (!PP_ISNORELOC(pp))
                panic("Illegal VA->PA translation, pp 0x%p not permanent",
                    (void *)pp);
        else
                panic("Illegal VA->PA translation, pp 0x%p not locked",
                    (void *)pp);
}
#endif  /* DEBUG */

/*
 * Returns a page frame number for a given virtual address.
 * Returns PFN_INVALID to indicate an invalid mapping
 */
pfn_t
hat_getpfnum(struct hat *hat, caddr_t addr)
{
        pfn_t pfn;
        tte_t tte;

        /*
         * We would like to
         * ASSERT(AS_LOCK_HELD(as));
         * but we can't because the iommu driver will call this
         * routine at interrupt time and it can't grab the as lock
         * or it will deadlock: A thread could have the as lock
         * and be waiting for io.  The io can't complete
         * because the interrupt thread is blocked trying to grab
         * the as lock.
         */

        if (hat == ksfmmup) {
                if (IS_KMEM_VA_LARGEPAGE(addr)) {
                        ASSERT(segkmem_lpszc > 0);
                        pfn = sfmmu_kvaszc2pfn(addr, segkmem_lpszc);
                        if (pfn != PFN_INVALID) {
                                sfmmu_check_kpfn(pfn);
                                return (pfn);
                        }
                } else if (segkpm && IS_KPM_ADDR(addr)) {
                        return (sfmmu_kpm_vatopfn(addr));
                }
                while ((pfn = sfmmu_vatopfn(addr, ksfmmup, &tte))
                    == PFN_SUSPENDED) {
                        sfmmu_vatopfn_suspended(addr, ksfmmup, &tte);
                }
                sfmmu_check_kpfn(pfn);
                return (pfn);
        } else {
                return (sfmmu_uvatopfn(addr, hat, NULL));
        }
}

/*
 * This routine will return both pfn and tte for the vaddr.
 */
static pfn_t
sfmmu_uvatopfn(caddr_t vaddr, struct hat *sfmmup, tte_t *ttep)
{
        struct hmehash_bucket *hmebp;
        hmeblk_tag hblktag;
        int hmeshift, hashno = 1;
        struct hme_blk *hmeblkp = NULL;
        tte_t tte;

        struct sf_hment *sfhmep;
        pfn_t pfn;

        /* support for ISM */
        ism_map_t       *ism_map;
        ism_blk_t       *ism_blkp;
        int             i;
        sfmmu_t *ism_hatid = NULL;
        sfmmu_t *locked_hatid = NULL;
        sfmmu_t *sv_sfmmup = sfmmup;
        caddr_t sv_vaddr = vaddr;
        sf_srd_t *srdp;

        if (ttep == NULL) {
                ttep = &tte;
        } else {
                ttep->ll = 0;
        }

        ASSERT(sfmmup != ksfmmup);
        SFMMU_STAT(sf_user_vtop);
        /*
         * Set ism_hatid if vaddr falls in a ISM segment.
         */
        ism_blkp = sfmmup->sfmmu_iblk;
        if (ism_blkp != NULL) {
                sfmmu_ismhat_enter(sfmmup, 0);
                locked_hatid = sfmmup;
        }
        while (ism_blkp != NULL && ism_hatid == NULL) {
                ism_map = ism_blkp->iblk_maps;
                for (i = 0; ism_map[i].imap_ismhat && i < ISM_MAP_SLOTS; i++) {
                        if (vaddr >= ism_start(ism_map[i]) &&
                            vaddr < ism_end(ism_map[i])) {
                                sfmmup = ism_hatid = ism_map[i].imap_ismhat;
                                vaddr = (caddr_t)(vaddr -
                                    ism_start(ism_map[i]));
                                break;
                        }
                }
                ism_blkp = ism_blkp->iblk_next;
        }
        if (locked_hatid) {
                sfmmu_ismhat_exit(locked_hatid, 0);
        }

        hblktag.htag_id = sfmmup;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;
        do {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_bspage = HME_HASH_BSPAGE(vaddr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(sfmmup, vaddr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);

                HME_HASH_FAST_SEARCH(hmebp, hblktag, hmeblkp);
                if (hmeblkp != NULL) {
                        ASSERT(!hmeblkp->hblk_shared);
                        HBLKTOHME(sfhmep, hmeblkp, vaddr);
                        sfmmu_copytte(&sfhmep->hme_tte, ttep);
                        SFMMU_HASH_UNLOCK(hmebp);
                        if (TTE_IS_VALID(ttep)) {
                                pfn = TTE_TO_PFN(vaddr, ttep);
                                return (pfn);
                        }
                        break;
                }
                SFMMU_HASH_UNLOCK(hmebp);
                hashno++;
        } while (HME_REHASH(sfmmup) && (hashno <= mmu_hashcnt));

        if (SF_HMERGNMAP_ISNULL(sv_sfmmup)) {
                return (PFN_INVALID);
        }
        srdp = sv_sfmmup->sfmmu_srdp;
        ASSERT(srdp != NULL);
        ASSERT(srdp->srd_refcnt != 0);
        hblktag.htag_id = srdp;
        hashno = 1;
        do {
                hmeshift = HME_HASH_SHIFT(hashno);
                hblktag.htag_bspage = HME_HASH_BSPAGE(sv_vaddr, hmeshift);
                hblktag.htag_rehash = hashno;
                hmebp = HME_HASH_FUNCTION(srdp, sv_vaddr, hmeshift);

                SFMMU_HASH_LOCK(hmebp);
                for (hmeblkp = hmebp->hmeblkp; hmeblkp != NULL;
                    hmeblkp = hmeblkp->hblk_next) {
                        uint_t rid;
                        sf_region_t *rgnp;
                        caddr_t rsaddr;
                        caddr_t readdr;

                        if (!HTAGS_EQ_SHME(hmeblkp->hblk_tag, hblktag,
                            sv_sfmmup->sfmmu_hmeregion_map)) {
                                continue;
                        }
                        ASSERT(hmeblkp->hblk_shared);
                        rid = hmeblkp->hblk_tag.htag_rid;
                        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                        rgnp = srdp->srd_hmergnp[rid];
                        SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp, rgnp, rid);
                        HBLKTOHME(sfhmep, hmeblkp, sv_vaddr);
                        sfmmu_copytte(&sfhmep->hme_tte, ttep);
                        rsaddr = rgnp->rgn_saddr;
                        readdr = rsaddr + rgnp->rgn_size;
#ifdef DEBUG
                        if (TTE_IS_VALID(ttep) ||
                            get_hblk_ttesz(hmeblkp) > TTE8K) {
                                caddr_t eva = tte_to_evaddr(hmeblkp, ttep);
                                ASSERT(eva > sv_vaddr);
                                ASSERT(sv_vaddr >= rsaddr);
                                ASSERT(sv_vaddr < readdr);
                                ASSERT(eva <= readdr);
                        }
#endif /* DEBUG */
                        /*
                         * Continue the search if we
                         * found an invalid 8K tte outside of the area
                         * covered by this hmeblk's region.
                         */
                        if (TTE_IS_VALID(ttep)) {
                                SFMMU_HASH_UNLOCK(hmebp);
                                pfn = TTE_TO_PFN(sv_vaddr, ttep);
                                return (pfn);
                        } else if (get_hblk_ttesz(hmeblkp) > TTE8K ||
                            (sv_vaddr >= rsaddr && sv_vaddr < readdr)) {
                                SFMMU_HASH_UNLOCK(hmebp);
                                pfn = PFN_INVALID;
                                return (pfn);
                        }
                }
                SFMMU_HASH_UNLOCK(hmebp);
                hashno++;
        } while (hashno <= mmu_hashcnt);
        return (PFN_INVALID);
}


/*
 * For compatability with AT&T and later optimizations
 */
/* ARGSUSED */
void
hat_map(struct hat *hat, caddr_t addr, size_t len, uint_t flags)
{
        ASSERT(hat != NULL);
}

/*
 * Return the number of mappings to a particular page.  This number is an
 * approximation of the number of people sharing the page.
 *
 * shared hmeblks or ism hmeblks are counted as 1 mapping here.
 * hat_page_checkshare() can be used to compare threshold to share
 * count that reflects the number of region sharers albeit at higher cost.
 */
ulong_t
hat_page_getshare(page_t *pp)
{
        page_t *spp = pp;       /* start page */
        kmutex_t *pml;
        ulong_t cnt;
        int index, sz = TTE64K;

        /*
         * We need to grab the mlist lock to make sure any outstanding
         * load/unloads complete.  Otherwise we could return zero
         * even though the unload(s) hasn't finished yet.
         */
        pml = sfmmu_mlist_enter(spp);
        cnt = spp->p_share;

#ifdef VAC
        if (kpm_enable)
                cnt += spp->p_kpmref;
#endif
        if (vpm_enable && pp->p_vpmref) {
                cnt += 1;
        }

        /*
         * If we have any large mappings, we count the number of
         * mappings that this large page is part of.
         */
        index = PP_MAPINDEX(spp);
        index >>= 1;
        while (index) {
                pp = PP_GROUPLEADER(spp, sz);
                if ((index & 0x1) && pp != spp) {
                        cnt += pp->p_share;
                        spp = pp;
                }
                index >>= 1;
                sz++;
        }
        sfmmu_mlist_exit(pml);
        return (cnt);
}

/*
 * Return 1 if the number of mappings exceeds sh_thresh. Return 0
 * otherwise. Count shared hmeblks by region's refcnt.
 */
int
hat_page_checkshare(page_t *pp, ulong_t sh_thresh)
{
        kmutex_t *pml;
        ulong_t cnt = 0;
        int index, sz = TTE8K;
        struct sf_hment *sfhme, *tmphme = NULL;
        struct hme_blk *hmeblkp;

        pml = sfmmu_mlist_enter(pp);

#ifdef VAC
        if (kpm_enable)
                cnt = pp->p_kpmref;
#endif

        if (vpm_enable && pp->p_vpmref) {
                cnt += 1;
        }

        if (pp->p_share + cnt > sh_thresh) {
                sfmmu_mlist_exit(pml);
                return (1);
        }

        index = PP_MAPINDEX(pp);

again:
        for (sfhme = pp->p_mapping; sfhme; sfhme = tmphme) {
                tmphme = sfhme->hme_next;
                if (IS_PAHME(sfhme)) {
                        continue;
                }

                hmeblkp = sfmmu_hmetohblk(sfhme);
                if (hme_size(sfhme) != sz) {
                        continue;
                }

                if (hmeblkp->hblk_shared) {
                        sf_srd_t *srdp = hblktosrd(hmeblkp);
                        uint_t rid = hmeblkp->hblk_tag.htag_rid;
                        sf_region_t *rgnp;
                        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                        ASSERT(srdp != NULL);
                        rgnp = srdp->srd_hmergnp[rid];
                        SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp,
                            rgnp, rid);
                        cnt += rgnp->rgn_refcnt;
                } else {
                        cnt++;
                }
                if (cnt > sh_thresh) {
                        sfmmu_mlist_exit(pml);
                        return (1);
                }
        }

        index >>= 1;
        sz++;
        while (index) {
                pp = PP_GROUPLEADER(pp, sz);
                ASSERT(sfmmu_mlist_held(pp));
                if (index & 0x1) {
                        goto again;
                }
                index >>= 1;
                sz++;
        }
        sfmmu_mlist_exit(pml);
        return (0);
}

/*
 * Unload all large mappings to the pp and reset the p_szc field of every
 * constituent page according to the remaining mappings.
 *
 * pp must be locked SE_EXCL. Even though no other constituent pages are
 * locked it's legal to unload the large mappings to the pp because all
 * constituent pages of large locked mappings have to be locked SE_SHARED.
 * This means if we have SE_EXCL lock on one of constituent pages none of the
 * large mappings to pp are locked.
 *
 * Decrease p_szc field starting from the last constituent page and ending
 * with the root page. This method is used because other threads rely on the
 * root's p_szc to find the lock to syncronize on. After a root page_t's p_szc
 * is demoted then other threads will succeed in sfmmu_mlspl_enter(). This
 * ensures that p_szc changes of the constituent pages appears atomic for all
 * threads that use sfmmu_mlspl_enter() to examine p_szc field.
 *
 * This mechanism is only used for file system pages where it's not always
 * possible to get SE_EXCL locks on all constituent pages to demote the size
 * code (as is done for anonymous or kernel large pages).
 *
 * See more comments in front of sfmmu_mlspl_enter().
 */
void
hat_page_demote(page_t *pp)
{
        int index;
        int sz;
        cpuset_t cpuset;
        int sync = 0;
        page_t *rootpp;
        struct sf_hment *sfhme;
        struct sf_hment *tmphme = NULL;
        uint_t pszc;
        page_t *lastpp;
        cpuset_t tset;
        pgcnt_t npgs;
        kmutex_t *pml;
        kmutex_t *pmtx = NULL;

        ASSERT(PAGE_EXCL(pp));
        ASSERT(!PP_ISFREE(pp));
        ASSERT(!PP_ISKAS(pp));
        ASSERT(page_szc_lock_assert(pp));
        pml = sfmmu_mlist_enter(pp);

        pszc = pp->p_szc;
        if (pszc == 0) {
                goto out;
        }

        index = PP_MAPINDEX(pp) >> 1;

        if (index) {
                CPUSET_ZERO(cpuset);
                sz = TTE64K;
                sync = 1;
        }

        while (index) {
                if (!(index & 0x1)) {
                        index >>= 1;
                        sz++;
                        continue;
                }
                ASSERT(sz <= pszc);
                rootpp = PP_GROUPLEADER(pp, sz);
                for (sfhme = rootpp->p_mapping; sfhme; sfhme = tmphme) {
                        tmphme = sfhme->hme_next;
                        ASSERT(!IS_PAHME(sfhme));
                        if (hme_size(sfhme) != sz) {
                                continue;
                        }
                        tset = sfmmu_pageunload(rootpp, sfhme, sz);
                        CPUSET_OR(cpuset, tset);
                }
                if (index >>= 1) {
                        sz++;
                }
        }

        ASSERT(!PP_ISMAPPED_LARGE(pp));

        if (sync) {
                xt_sync(cpuset);
#ifdef VAC
                if (PP_ISTNC(pp)) {
                        conv_tnc(rootpp, sz);
                }
#endif  /* VAC */
        }

        pmtx = sfmmu_page_enter(pp);

        ASSERT(pp->p_szc == pszc);
        rootpp = PP_PAGEROOT(pp);
        ASSERT(rootpp->p_szc == pszc);
        lastpp = PP_PAGENEXT_N(rootpp, TTEPAGES(pszc) - 1);

        while (lastpp != rootpp) {
                sz = PP_MAPINDEX(lastpp) ? fnd_mapping_sz(lastpp) : 0;
                ASSERT(sz < pszc);
                npgs = (sz == 0) ? 1 : TTEPAGES(sz);
                ASSERT(P2PHASE(lastpp->p_pagenum, npgs) == npgs - 1);
                while (--npgs > 0) {
                        lastpp->p_szc = (uchar_t)sz;
                        lastpp = PP_PAGEPREV(lastpp);
                }
                if (sz) {
                        /*
                         * make sure before current root's pszc
                         * is updated all updates to constituent pages pszc
                         * fields are globally visible.
                         */
                        membar_producer();
                }
                lastpp->p_szc = sz;
                ASSERT(IS_P2ALIGNED(lastpp->p_pagenum, TTEPAGES(sz)));
                if (lastpp != rootpp) {
                        lastpp = PP_PAGEPREV(lastpp);
                }
        }
        if (sz == 0) {
                /* the loop above doesn't cover this case */
                rootpp->p_szc = 0;
        }
out:
        ASSERT(pp->p_szc == 0);
        if (pmtx != NULL) {
                sfmmu_page_exit(pmtx);
        }
        sfmmu_mlist_exit(pml);
}

/*
 * Refresh the HAT ismttecnt[] element for size szc.
 * Caller must have set ISM busy flag to prevent mapping
 * lists from changing while we're traversing them.
 */
pgcnt_t
ism_tsb_entries(sfmmu_t *sfmmup, int szc)
{
        ism_blk_t       *ism_blkp = sfmmup->sfmmu_iblk;
        ism_map_t       *ism_map;
        pgcnt_t         npgs = 0;
        pgcnt_t         npgs_scd = 0;
        int             j;
        sf_scd_t        *scdp;
        uchar_t         rid;

        ASSERT(SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY));
        scdp = sfmmup->sfmmu_scdp;

        for (; ism_blkp != NULL; ism_blkp = ism_blkp->iblk_next) {
                ism_map = ism_blkp->iblk_maps;
                for (j = 0; ism_map[j].imap_ismhat && j < ISM_MAP_SLOTS; j++) {
                        rid = ism_map[j].imap_rid;
                        ASSERT(rid == SFMMU_INVALID_ISMRID ||
                            rid < sfmmup->sfmmu_srdp->srd_next_ismrid);

                        if (scdp != NULL && rid != SFMMU_INVALID_ISMRID &&
                            SF_RGNMAP_TEST(scdp->scd_ismregion_map, rid)) {
                                /* ISM is in sfmmup's SCD */
                                npgs_scd +=
                                    ism_map[j].imap_ismhat->sfmmu_ttecnt[szc];
                        } else {
                                /* ISMs is not in SCD */
                                npgs +=
                                    ism_map[j].imap_ismhat->sfmmu_ttecnt[szc];
                        }
                }
        }
        sfmmup->sfmmu_ismttecnt[szc] = npgs;
        sfmmup->sfmmu_scdismttecnt[szc] = npgs_scd;
        return (npgs);
}

/*
 * Yield the memory claim requirement for an address space.
 *
 * This is currently implemented as the number of bytes that have active
 * hardware translations that have page structures.  Therefore, it can
 * underestimate the traditional resident set size, eg, if the
 * physical page is present and the hardware translation is missing;
 * and it can overestimate the rss, eg, if there are active
 * translations to a frame buffer with page structs.
 * Also, it does not take sharing into account.
 *
 * Note that we don't acquire locks here since this function is most often
 * called from the clock thread.
 */
size_t
hat_get_mapped_size(struct hat *hat)
{
        size_t          assize = 0;
        int             i;

        if (hat == NULL)
                return (0);

        for (i = 0; i < mmu_page_sizes; i++)
                assize += ((pgcnt_t)hat->sfmmu_ttecnt[i] +
                    (pgcnt_t)hat->sfmmu_scdrttecnt[i]) * TTEBYTES(i);

        if (hat->sfmmu_iblk == NULL)
                return (assize);

        for (i = 0; i < mmu_page_sizes; i++)
                assize += ((pgcnt_t)hat->sfmmu_ismttecnt[i] +
                    (pgcnt_t)hat->sfmmu_scdismttecnt[i]) * TTEBYTES(i);

        return (assize);
}

int
hat_stats_enable(struct hat *hat)
{
        hatlock_t       *hatlockp;

        hatlockp = sfmmu_hat_enter(hat);
        hat->sfmmu_rmstat++;
        sfmmu_hat_exit(hatlockp);
        return (1);
}

void
hat_stats_disable(struct hat *hat)
{
        hatlock_t       *hatlockp;

        hatlockp = sfmmu_hat_enter(hat);
        hat->sfmmu_rmstat--;
        sfmmu_hat_exit(hatlockp);
}

/*
 * Routines for entering or removing  ourselves from the
 * ism_hat's mapping list. This is used for both private and
 * SCD hats.
 */
static void
iment_add(struct ism_ment *iment,  struct hat *ism_hat)
{
        ASSERT(MUTEX_HELD(&ism_mlist_lock));

        iment->iment_prev = NULL;
        iment->iment_next = ism_hat->sfmmu_iment;
        if (ism_hat->sfmmu_iment) {
                ism_hat->sfmmu_iment->iment_prev = iment;
        }
        ism_hat->sfmmu_iment = iment;
}

static void
iment_sub(struct ism_ment *iment, struct hat *ism_hat)
{
        ASSERT(MUTEX_HELD(&ism_mlist_lock));

        if (ism_hat->sfmmu_iment == NULL) {
                panic("ism map entry remove - no entries");
        }

        if (iment->iment_prev) {
                ASSERT(ism_hat->sfmmu_iment != iment);
                iment->iment_prev->iment_next = iment->iment_next;
        } else {
                ASSERT(ism_hat->sfmmu_iment == iment);
                ism_hat->sfmmu_iment = iment->iment_next;
        }

        if (iment->iment_next) {
                iment->iment_next->iment_prev = iment->iment_prev;
        }

        /*
         * zero out the entry
         */
        iment->iment_next = NULL;
        iment->iment_prev = NULL;
        iment->iment_hat =  NULL;
        iment->iment_base_va = 0;
}

/*
 * Hat_share()/unshare() return an (non-zero) error
 * when saddr and daddr are not properly aligned.
 *
 * The top level mapping element determines the alignment
 * requirement for saddr and daddr, depending on different
 * architectures.
 *
 * When hat_share()/unshare() are not supported,
 * HATOP_SHARE()/UNSHARE() return 0
 */
int
hat_share(struct hat *sfmmup, caddr_t addr, struct hat *ism_hatid,
    caddr_t sptaddr, size_t len, uint_t ismszc)
{
        ism_blk_t       *ism_blkp;
        ism_blk_t       *new_iblk;
        ism_map_t       *ism_map;
        ism_ment_t      *ism_ment;
        int             i, added;
        hatlock_t       *hatlockp;
        int             reload_mmu = 0;
        uint_t          ismshift = page_get_shift(ismszc);
        size_t          ismpgsz = page_get_pagesize(ismszc);
        uint_t          ismmask = (uint_t)ismpgsz - 1;
        size_t          sh_size = ISM_SHIFT(ismshift, len);
        ushort_t        ismhatflag;
        hat_region_cookie_t rcookie;
        sf_scd_t        *old_scdp;

#ifdef DEBUG
        caddr_t         eaddr = addr + len;
#endif /* DEBUG */

        ASSERT(ism_hatid != NULL && sfmmup != NULL);
        ASSERT(sptaddr == ISMID_STARTADDR);
        /*
         * Check the alignment.
         */
        if (!ISM_ALIGNED(ismshift, addr) || !ISM_ALIGNED(ismshift, sptaddr))
                return (EINVAL);

        /*
         * Check size alignment.
         */
        if (!ISM_ALIGNED(ismshift, len))
                return (EINVAL);

        /*
         * Allocate ism_ment for the ism_hat's mapping list, and an
         * ism map blk in case we need one.  We must do our
         * allocations before acquiring locks to prevent a deadlock
         * in the kmem allocator on the mapping list lock.
         */
        new_iblk = kmem_cache_alloc(ism_blk_cache, KM_SLEEP);
        ism_ment = kmem_cache_alloc(ism_ment_cache, KM_SLEEP);

        /*
         * Serialize ISM mappings with the ISM busy flag, and also the
         * trap handlers.
         */
        sfmmu_ismhat_enter(sfmmup, 0);

        /*
         * Allocate an ism map blk if necessary.
         */
        if (sfmmup->sfmmu_iblk == NULL) {
                sfmmup->sfmmu_iblk = new_iblk;
                bzero(new_iblk, sizeof (*new_iblk));
                new_iblk->iblk_nextpa = (uint64_t)-1;
                membar_stst();  /* make sure next ptr visible to all CPUs */
                sfmmup->sfmmu_ismblkpa = va_to_pa((caddr_t)new_iblk);
                reload_mmu = 1;
                new_iblk = NULL;
        }

#ifdef DEBUG
        /*
         * Make sure mapping does not already exist.
         */
        ism_blkp = sfmmup->sfmmu_iblk;
        while (ism_blkp != NULL) {
                ism_map = ism_blkp->iblk_maps;
                for (i = 0; i < ISM_MAP_SLOTS && ism_map[i].imap_ismhat; i++) {
                        if ((addr >= ism_start(ism_map[i]) &&
                            addr < ism_end(ism_map[i])) ||
                            eaddr > ism_start(ism_map[i]) &&
                            eaddr <= ism_end(ism_map[i])) {
                                panic("sfmmu_share: Already mapped!");
                        }
                }
                ism_blkp = ism_blkp->iblk_next;
        }
#endif /* DEBUG */

        ASSERT(ismszc >= TTE4M);
        if (ismszc == TTE4M) {
                ismhatflag = HAT_4M_FLAG;
        } else if (ismszc == TTE32M) {
                ismhatflag = HAT_32M_FLAG;
        } else if (ismszc == TTE256M) {
                ismhatflag = HAT_256M_FLAG;
        }
        /*
         * Add mapping to first available mapping slot.
         */
        ism_blkp = sfmmup->sfmmu_iblk;
        added = 0;
        while (!added) {
                ism_map = ism_blkp->iblk_maps;
                for (i = 0; i < ISM_MAP_SLOTS; i++)  {
                        if (ism_map[i].imap_ismhat == NULL) {

                                ism_map[i].imap_ismhat = ism_hatid;
                                ism_map[i].imap_vb_shift = (uchar_t)ismshift;
                                ism_map[i].imap_rid = SFMMU_INVALID_ISMRID;
                                ism_map[i].imap_hatflags = ismhatflag;
                                ism_map[i].imap_sz_mask = ismmask;
                                /*
                                 * imap_seg is checked in ISM_CHECK to see if
                                 * non-NULL, then other info assumed valid.
                                 */
                                membar_stst();
                                ism_map[i].imap_seg = (uintptr_t)addr | sh_size;
                                ism_map[i].imap_ment = ism_ment;

                                /*
                                 * Now add ourselves to the ism_hat's
                                 * mapping list.
                                 */
                                ism_ment->iment_hat = sfmmup;
                                ism_ment->iment_base_va = addr;
                                ism_hatid->sfmmu_ismhat = 1;
                                mutex_enter(&ism_mlist_lock);
                                iment_add(ism_ment, ism_hatid);
                                mutex_exit(&ism_mlist_lock);
                                added = 1;
                                break;
                        }
                }
                if (!added && ism_blkp->iblk_next == NULL) {
                        ism_blkp->iblk_next = new_iblk;
                        new_iblk = NULL;
                        bzero(ism_blkp->iblk_next,
                            sizeof (*ism_blkp->iblk_next));
                        ism_blkp->iblk_next->iblk_nextpa = (uint64_t)-1;
                        membar_stst();
                        ism_blkp->iblk_nextpa =
                            va_to_pa((caddr_t)ism_blkp->iblk_next);
                }
                ism_blkp = ism_blkp->iblk_next;
        }

        /*
         * After calling hat_join_region, sfmmup may join a new SCD or
         * move from the old scd to a new scd, in which case, we want to
         * shrink the sfmmup's private tsb size, i.e., pass shrink to
         * sfmmu_check_page_sizes at the end of this routine.
         */
        old_scdp = sfmmup->sfmmu_scdp;

        rcookie = hat_join_region(sfmmup, addr, len, (void *)ism_hatid, 0,
            PROT_ALL, ismszc, NULL, HAT_REGION_ISM);
        if (rcookie != HAT_INVALID_REGION_COOKIE) {
                ism_map[i].imap_rid = (uchar_t)((uint64_t)rcookie);
        }
        /*
         * Update our counters for this sfmmup's ism mappings.
         */
        for (i = 0; i <= ismszc; i++) {
                if (!(disable_ism_large_pages & (1 << i)))
                        (void) ism_tsb_entries(sfmmup, i);
        }

        /*
         * For ISM and DISM we do not support 512K pages, so we only only
         * search the 4M and 8K/64K hashes for 4 pagesize cpus, and search the
         * 256M or 32M, and 4M and 8K/64K hashes for 6 pagesize cpus.
         *
         * Need to set 32M/256M ISM flags to make sure
         * sfmmu_check_page_sizes() enables them on Panther.
         */
        ASSERT((disable_ism_large_pages & (1 << TTE512K)) != 0);

        switch (ismszc) {
        case TTE256M:
                if (!SFMMU_FLAGS_ISSET(sfmmup, HAT_256M_ISM)) {
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        SFMMU_FLAGS_SET(sfmmup, HAT_256M_ISM);
                        sfmmu_hat_exit(hatlockp);
                }
                break;
        case TTE32M:
                if (!SFMMU_FLAGS_ISSET(sfmmup, HAT_32M_ISM)) {
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        SFMMU_FLAGS_SET(sfmmup, HAT_32M_ISM);
                        sfmmu_hat_exit(hatlockp);
                }
                break;
        default:
                break;
        }

        /*
         * If we updated the ismblkpa for this HAT we must make
         * sure all CPUs running this process reload their tsbmiss area.
         * Otherwise they will fail to load the mappings in the tsbmiss
         * handler and will loop calling pagefault().
         */
        if (reload_mmu) {
                hatlockp = sfmmu_hat_enter(sfmmup);
                sfmmu_sync_mmustate(sfmmup);
                sfmmu_hat_exit(hatlockp);
        }

        sfmmu_ismhat_exit(sfmmup, 0);

        /*
         * Free up ismblk if we didn't use it.
         */
        if (new_iblk != NULL)
                kmem_cache_free(ism_blk_cache, new_iblk);

        /*
         * Check TSB and TLB page sizes.
         */
        if (sfmmup->sfmmu_scdp != NULL && old_scdp != sfmmup->sfmmu_scdp) {
                sfmmu_check_page_sizes(sfmmup, 0);
        } else {
                sfmmu_check_page_sizes(sfmmup, 1);
        }
        return (0);
}

/*
 * hat_unshare removes exactly one ism_map from
 * this process's as.  It expects multiple calls
 * to hat_unshare for multiple shm segments.
 */
void
hat_unshare(struct hat *sfmmup, caddr_t addr, size_t len, uint_t ismszc)
{
        ism_map_t       *ism_map;
        ism_ment_t      *free_ment = NULL;
        ism_blk_t       *ism_blkp;
        struct hat      *ism_hatid;
        int             found, i;
        hatlock_t       *hatlockp;
        struct tsb_info *tsbinfo;
        uint_t          ismshift = page_get_shift(ismszc);
        size_t          sh_size = ISM_SHIFT(ismshift, len);
        uchar_t         ism_rid;
        sf_scd_t        *old_scdp;

        ASSERT(ISM_ALIGNED(ismshift, addr));
        ASSERT(ISM_ALIGNED(ismshift, len));
        ASSERT(sfmmup != NULL);
        ASSERT(sfmmup != ksfmmup);

        ASSERT(sfmmup->sfmmu_as != NULL);

        /*
         * Make sure that during the entire time ISM mappings are removed,
         * the trap handlers serialize behind us, and that no one else
         * can be mucking with ISM mappings.  This also lets us get away
         * with not doing expensive cross calls to flush the TLB -- we
         * just discard the context, flush the entire TSB, and call it
         * a day.
         */
        sfmmu_ismhat_enter(sfmmup, 0);

        /*
         * Remove the mapping.
         *
         * We can't have any holes in the ism map.
         * The tsb miss code while searching the ism map will
         * stop on an empty map slot.  So we must move
         * everyone past the hole up 1 if any.
         *
         * Also empty ism map blks are not freed until the
         * process exits. This is to prevent a MT race condition
         * between sfmmu_unshare() and sfmmu_tsbmiss_exception().
         */
        found = 0;
        ism_blkp = sfmmup->sfmmu_iblk;
        while (!found && ism_blkp != NULL) {
                ism_map = ism_blkp->iblk_maps;
                for (i = 0; i < ISM_MAP_SLOTS; i++) {
                        if (addr == ism_start(ism_map[i]) &&
                            sh_size == (size_t)(ism_size(ism_map[i]))) {
                                found = 1;
                                break;
                        }
                }
                if (!found)
                        ism_blkp = ism_blkp->iblk_next;
        }

        if (found) {
                ism_hatid = ism_map[i].imap_ismhat;
                ism_rid = ism_map[i].imap_rid;
                ASSERT(ism_hatid != NULL);
                ASSERT(ism_hatid->sfmmu_ismhat == 1);

                /*
                 * After hat_leave_region, the sfmmup may leave SCD,
                 * in which case, we want to grow the private tsb size when
                 * calling sfmmu_check_page_sizes at the end of the routine.
                 */
                old_scdp = sfmmup->sfmmu_scdp;
                /*
                 * Then remove ourselves from the region.
                 */
                if (ism_rid != SFMMU_INVALID_ISMRID) {
                        hat_leave_region(sfmmup, (void *)((uint64_t)ism_rid),
                            HAT_REGION_ISM);
                }

                /*
                 * And now guarantee that any other cpu
                 * that tries to process an ISM miss
                 * will go to tl=0.
                 */
                hatlockp = sfmmu_hat_enter(sfmmup);
                sfmmu_invalidate_ctx(sfmmup);
                sfmmu_hat_exit(hatlockp);

                /*
                 * Remove ourselves from the ism mapping list.
                 */
                mutex_enter(&ism_mlist_lock);
                iment_sub(ism_map[i].imap_ment, ism_hatid);
                mutex_exit(&ism_mlist_lock);
                free_ment = ism_map[i].imap_ment;

                /*
                 * We delete the ism map by copying
                 * the next map over the current one.
                 * We will take the next one in the maps
                 * array or from the next ism_blk.
                 */
                while (ism_blkp != NULL) {
                        ism_map = ism_blkp->iblk_maps;
                        while (i < (ISM_MAP_SLOTS - 1)) {
                                ism_map[i] = ism_map[i + 1];
                                i++;
                        }
                        /* i == (ISM_MAP_SLOTS - 1) */
                        ism_blkp = ism_blkp->iblk_next;
                        if (ism_blkp != NULL) {
                                ism_map[i] = ism_blkp->iblk_maps[0];
                                i = 0;
                        } else {
                                ism_map[i].imap_seg = 0;
                                ism_map[i].imap_vb_shift = 0;
                                ism_map[i].imap_rid = SFMMU_INVALID_ISMRID;
                                ism_map[i].imap_hatflags = 0;
                                ism_map[i].imap_sz_mask = 0;
                                ism_map[i].imap_ismhat = NULL;
                                ism_map[i].imap_ment = NULL;
                        }
                }

                /*
                 * Now flush entire TSB for the process, since
                 * demapping page by page can be too expensive.
                 * We don't have to flush the TLB here anymore
                 * since we switch to a new TLB ctx instead.
                 * Also, there is no need to flush if the process
                 * is exiting since the TSB will be freed later.
                 */
                if (!sfmmup->sfmmu_free) {
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        for (tsbinfo = sfmmup->sfmmu_tsb; tsbinfo != NULL;
                            tsbinfo = tsbinfo->tsb_next) {
                                if (tsbinfo->tsb_flags & TSB_SWAPPED)
                                        continue;
                                if (tsbinfo->tsb_flags & TSB_RELOC_FLAG) {
                                        tsbinfo->tsb_flags |=
                                            TSB_FLUSH_NEEDED;
                                        continue;
                                }

                                sfmmu_inv_tsb(tsbinfo->tsb_va,
                                    TSB_BYTES(tsbinfo->tsb_szc));
                        }
                        sfmmu_hat_exit(hatlockp);
                }
        }

        /*
         * Update our counters for this sfmmup's ism mappings.
         */
        for (i = 0; i <= ismszc; i++) {
                if (!(disable_ism_large_pages & (1 << i)))
                        (void) ism_tsb_entries(sfmmup, i);
        }

        sfmmu_ismhat_exit(sfmmup, 0);

        /*
         * We must do our freeing here after dropping locks
         * to prevent a deadlock in the kmem allocator on the
         * mapping list lock.
         */
        if (free_ment != NULL)
                kmem_cache_free(ism_ment_cache, free_ment);

        /*
         * Check TSB and TLB page sizes if the process isn't exiting.
         */
        if (!sfmmup->sfmmu_free) {
                if (found && old_scdp != NULL && sfmmup->sfmmu_scdp == NULL) {
                        sfmmu_check_page_sizes(sfmmup, 1);
                } else {
                        sfmmu_check_page_sizes(sfmmup, 0);
                }
        }
}

/* ARGSUSED */
static int
sfmmu_idcache_constructor(void *buf, void *cdrarg, int kmflags)
{
        /* void *buf is sfmmu_t pointer */
        bzero(buf, sizeof (sfmmu_t));

        return (0);
}

/* ARGSUSED */
static void
sfmmu_idcache_destructor(void *buf, void *cdrarg)
{
        /* void *buf is sfmmu_t pointer */
}

/*
 * setup kmem hmeblks by bzeroing all members and initializing the nextpa
 * field to be the pa of this hmeblk
 */
/* ARGSUSED */
static int
sfmmu_hblkcache_constructor(void *buf, void *cdrarg, int kmflags)
{
        struct hme_blk *hmeblkp;

        bzero(buf, (size_t)cdrarg);
        hmeblkp = (struct hme_blk *)buf;
        hmeblkp->hblk_nextpa = va_to_pa((caddr_t)hmeblkp);

#ifdef  HBLK_TRACE
        mutex_init(&hmeblkp->hblk_audit_lock, NULL, MUTEX_DEFAULT, NULL);
#endif  /* HBLK_TRACE */

        return (0);
}

/* ARGSUSED */
static void
sfmmu_hblkcache_destructor(void *buf, void *cdrarg)
{

#ifdef  HBLK_TRACE

        struct hme_blk *hmeblkp;

        hmeblkp = (struct hme_blk *)buf;
        mutex_destroy(&hmeblkp->hblk_audit_lock);

#endif  /* HBLK_TRACE */
}

#define SFMMU_CACHE_RECLAIM_SCAN_RATIO 8
static int sfmmu_cache_reclaim_scan_ratio = SFMMU_CACHE_RECLAIM_SCAN_RATIO;
/*
 * The kmem allocator will callback into our reclaim routine when the system
 * is running low in memory.  We traverse the hash and free up all unused but
 * still cached hme_blks.  We also traverse the free list and free them up
 * as well.
 */
/*ARGSUSED*/
static void
sfmmu_hblkcache_reclaim(void *cdrarg)
{
        int i;
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp, *nx_hblk, *pr_hblk = NULL;
        static struct hmehash_bucket *uhmehash_reclaim_hand;
        static struct hmehash_bucket *khmehash_reclaim_hand;
        struct hme_blk *list = NULL, *last_hmeblkp;
        cpuset_t cpuset = cpu_ready_set;
        cpu_hme_pend_t *cpuhp;

        /* Free up hmeblks on the cpu pending lists */
        for (i = 0; i < NCPU; i++) {
                cpuhp = &cpu_hme_pend[i];
                if (cpuhp->chp_listp != NULL)  {
                        mutex_enter(&cpuhp->chp_mutex);
                        if (cpuhp->chp_listp == NULL) {
                                mutex_exit(&cpuhp->chp_mutex);
                                continue;
                        }
                        for (last_hmeblkp = cpuhp->chp_listp;
                            last_hmeblkp->hblk_next != NULL;
                            last_hmeblkp = last_hmeblkp->hblk_next)
                                ;
                        last_hmeblkp->hblk_next = list;
                        list = cpuhp->chp_listp;
                        cpuhp->chp_listp = NULL;
                        cpuhp->chp_count = 0;
                        mutex_exit(&cpuhp->chp_mutex);
                }

        }

        if (list != NULL) {
                kpreempt_disable();
                CPUSET_DEL(cpuset, CPU->cpu_id);
                xt_sync(cpuset);
                xt_sync(cpuset);
                kpreempt_enable();
                sfmmu_hblk_free(&list);
                list = NULL;
        }

        hmebp = uhmehash_reclaim_hand;
        if (hmebp == NULL || hmebp > &uhme_hash[UHMEHASH_SZ])
                uhmehash_reclaim_hand = hmebp = uhme_hash;
        uhmehash_reclaim_hand += UHMEHASH_SZ / sfmmu_cache_reclaim_scan_ratio;

        for (i = UHMEHASH_SZ / sfmmu_cache_reclaim_scan_ratio; i; i--) {
                if (SFMMU_HASH_LOCK_TRYENTER(hmebp) != 0) {
                        hmeblkp = hmebp->hmeblkp;
                        pr_hblk = NULL;
                        while (hmeblkp) {
                                nx_hblk = hmeblkp->hblk_next;
                                if (!hmeblkp->hblk_vcnt &&
                                    !hmeblkp->hblk_hmecnt) {
                                        sfmmu_hblk_hash_rm(hmebp, hmeblkp,
                                            pr_hblk, &list, 0);
                                } else {
                                        pr_hblk = hmeblkp;
                                }
                                hmeblkp = nx_hblk;
                        }
                        SFMMU_HASH_UNLOCK(hmebp);
                }
                if (hmebp++ == &uhme_hash[UHMEHASH_SZ])
                        hmebp = uhme_hash;
        }

        hmebp = khmehash_reclaim_hand;
        if (hmebp == NULL || hmebp > &khme_hash[KHMEHASH_SZ])
                khmehash_reclaim_hand = hmebp = khme_hash;
        khmehash_reclaim_hand += KHMEHASH_SZ / sfmmu_cache_reclaim_scan_ratio;

        for (i = KHMEHASH_SZ / sfmmu_cache_reclaim_scan_ratio; i; i--) {
                if (SFMMU_HASH_LOCK_TRYENTER(hmebp) != 0) {
                        hmeblkp = hmebp->hmeblkp;
                        pr_hblk = NULL;
                        while (hmeblkp) {
                                nx_hblk = hmeblkp->hblk_next;
                                if (!hmeblkp->hblk_vcnt &&
                                    !hmeblkp->hblk_hmecnt) {
                                        sfmmu_hblk_hash_rm(hmebp, hmeblkp,
                                            pr_hblk, &list, 0);
                                } else {
                                        pr_hblk = hmeblkp;
                                }
                                hmeblkp = nx_hblk;
                        }
                        SFMMU_HASH_UNLOCK(hmebp);
                }
                if (hmebp++ == &khme_hash[KHMEHASH_SZ])
                        hmebp = khme_hash;
        }
        sfmmu_hblks_list_purge(&list, 0);
}

/*
 * sfmmu_get_ppvcolor should become a vm_machdep or hatop interface.
 * same goes for sfmmu_get_addrvcolor().
 *
 * This function will return the virtual color for the specified page. The
 * virtual color corresponds to this page current mapping or its last mapping.
 * It is used by memory allocators to choose addresses with the correct
 * alignment so vac consistency is automatically maintained.  If the page
 * has no color it returns -1.
 */
/*ARGSUSED*/
int
sfmmu_get_ppvcolor(struct page *pp)
{
#ifdef VAC
        int color;

        if (!(cache & CACHE_VAC) || PP_NEWPAGE(pp)) {
                return (-1);
        }
        color = PP_GET_VCOLOR(pp);
        ASSERT(color < mmu_btop(shm_alignment));
        return (color);
#else
        return (-1);
#endif  /* VAC */
}

/*
 * This function will return the desired alignment for vac consistency
 * (vac color) given a virtual address.  If no vac is present it returns -1.
 */
/*ARGSUSED*/
int
sfmmu_get_addrvcolor(caddr_t vaddr)
{
#ifdef VAC
        if (cache & CACHE_VAC) {
                return (addr_to_vcolor(vaddr));
        } else {
                return (-1);
        }
#else
        return (-1);
#endif  /* VAC */
}

#ifdef VAC
/*
 * Check for conflicts.
 * A conflict exists if the new and existent mappings do not match in
 * their "shm_alignment fields. If conflicts exist, the existant mappings
 * are flushed unless one of them is locked. If one of them is locked, then
 * the mappings are flushed and converted to non-cacheable mappings.
 */
static void
sfmmu_vac_conflict(struct hat *hat, caddr_t addr, page_t *pp)
{
        struct hat *tmphat;
        struct sf_hment *sfhmep, *tmphme = NULL;
        struct hme_blk *hmeblkp;
        int vcolor;
        tte_t tte;

        ASSERT(sfmmu_mlist_held(pp));
        ASSERT(!PP_ISNC(pp));           /* page better be cacheable */

        vcolor = addr_to_vcolor(addr);
        if (PP_NEWPAGE(pp)) {
                PP_SET_VCOLOR(pp, vcolor);
                return;
        }

        if (PP_GET_VCOLOR(pp) == vcolor) {
                return;
        }

        if (!PP_ISMAPPED(pp) && !PP_ISMAPPED_KPM(pp)) {
                /*
                 * Previous user of page had a different color
                 * but since there are no current users
                 * we just flush the cache and change the color.
                 */
                SFMMU_STAT(sf_pgcolor_conflict);
                sfmmu_cache_flush(pp->p_pagenum, PP_GET_VCOLOR(pp));
                PP_SET_VCOLOR(pp, vcolor);
                return;
        }

        /*
         * If we get here we have a vac conflict with a current
         * mapping.  VAC conflict policy is as follows.
         * - The default is to unload the other mappings unless:
         * - If we have a large mapping we uncache the page.
         * We need to uncache the rest of the large page too.
         * - If any of the mappings are locked we uncache the page.
         * - If the requested mapping is inconsistent
         * with another mapping and that mapping
         * is in the same address space we have to
         * make it non-cached.  The default thing
         * to do is unload the inconsistent mapping
         * but if they are in the same address space
         * we run the risk of unmapping the pc or the
         * stack which we will use as we return to the user,
         * in which case we can then fault on the thing
         * we just unloaded and get into an infinite loop.
         */
        if (PP_ISMAPPED_LARGE(pp)) {
                int sz;

                /*
                 * Existing mapping is for big pages. We don't unload
                 * existing big mappings to satisfy new mappings.
                 * Always convert all mappings to TNC.
                 */
                sz = fnd_mapping_sz(pp);
                pp = PP_GROUPLEADER(pp, sz);
                SFMMU_STAT_ADD(sf_uncache_conflict, TTEPAGES(sz));
                sfmmu_page_cache_array(pp, HAT_TMPNC, CACHE_FLUSH,
                    TTEPAGES(sz));

                return;
        }

        /*
         * check if any mapping is in same as or if it is locked
         * since in that case we need to uncache.
         */
        for (sfhmep = pp->p_mapping; sfhmep; sfhmep = tmphme) {
                tmphme = sfhmep->hme_next;
                if (IS_PAHME(sfhmep))
                        continue;
                hmeblkp = sfmmu_hmetohblk(sfhmep);
                tmphat = hblktosfmmu(hmeblkp);
                sfmmu_copytte(&sfhmep->hme_tte, &tte);
                ASSERT(TTE_IS_VALID(&tte));
                if (hmeblkp->hblk_shared || tmphat == hat ||
                    hmeblkp->hblk_lckcnt) {
                        /*
                         * We have an uncache conflict
                         */
                        SFMMU_STAT(sf_uncache_conflict);
                        sfmmu_page_cache_array(pp, HAT_TMPNC, CACHE_FLUSH, 1);
                        return;
                }
        }

        /*
         * We have an unload conflict
         * We have already checked for LARGE mappings, therefore
         * the remaining mapping(s) must be TTE8K.
         */
        SFMMU_STAT(sf_unload_conflict);

        for (sfhmep = pp->p_mapping; sfhmep; sfhmep = tmphme) {
                tmphme = sfhmep->hme_next;
                if (IS_PAHME(sfhmep))
                        continue;
                hmeblkp = sfmmu_hmetohblk(sfhmep);
                ASSERT(!hmeblkp->hblk_shared);
                (void) sfmmu_pageunload(pp, sfhmep, TTE8K);
        }

        if (PP_ISMAPPED_KPM(pp))
                sfmmu_kpm_vac_unload(pp, addr);

        /*
         * Unloads only do TLB flushes so we need to flush the
         * cache here.
         */
        sfmmu_cache_flush(pp->p_pagenum, PP_GET_VCOLOR(pp));
        PP_SET_VCOLOR(pp, vcolor);
}

/*
 * Whenever a mapping is unloaded and the page is in TNC state,
 * we see if the page can be made cacheable again. 'pp' is
 * the page that we just unloaded a mapping from, the size
 * of mapping that was unloaded is 'ottesz'.
 * Remark:
 * The recache policy for mpss pages can leave a performance problem
 * under the following circumstances:
 * . A large page in uncached mode has just been unmapped.
 * . All constituent pages are TNC due to a conflicting small mapping.
 * . There are many other, non conflicting, small mappings around for
 *   a lot of the constituent pages.
 * . We're called w/ the "old" groupleader page and the old ottesz,
 *   but this is irrelevant, since we're no more "PP_ISMAPPED_LARGE", so
 *   we end up w/ TTE8K or npages == 1.
 * . We call tst_tnc w/ the old groupleader only, and if there is no
 *   conflict, we re-cache only this page.
 * . All other small mappings are not checked and will be left in TNC mode.
 * The problem is not very serious because:
 * . mpss is actually only defined for heap and stack, so the probability
 *   is not very high that a large page mapping exists in parallel to a small
 *   one (this is possible, but seems to be bad programming style in the
 *   appl).
 * . The problem gets a little bit more serious, when those TNC pages
 *   have to be mapped into kernel space, e.g. for networking.
 * . When VAC alias conflicts occur in applications, this is regarded
 *   as an application bug. So if kstat's show them, the appl should
 *   be changed anyway.
 */
void
conv_tnc(page_t *pp, int ottesz)
{
        int cursz, dosz;
        pgcnt_t curnpgs, dopgs;
        pgcnt_t pg64k;
        page_t *pp2;

        /*
         * Determine how big a range we check for TNC and find
         * leader page. cursz is the size of the biggest
         * mapping that still exist on 'pp'.
         */
        if (PP_ISMAPPED_LARGE(pp)) {
                cursz = fnd_mapping_sz(pp);
        } else {
                cursz = TTE8K;
        }

        if (ottesz >= cursz) {
                dosz = ottesz;
                pp2 = pp;
        } else {
                dosz = cursz;
                pp2 = PP_GROUPLEADER(pp, dosz);
        }

        pg64k = TTEPAGES(TTE64K);
        dopgs = TTEPAGES(dosz);

        ASSERT(dopgs == 1 || ((dopgs & (pg64k - 1)) == 0));

        while (dopgs != 0) {
                curnpgs = TTEPAGES(cursz);
                if (tst_tnc(pp2, curnpgs)) {
                        SFMMU_STAT_ADD(sf_recache, curnpgs);
                        sfmmu_page_cache_array(pp2, HAT_CACHE, CACHE_NO_FLUSH,
                            curnpgs);
                }

                ASSERT(dopgs >= curnpgs);
                dopgs -= curnpgs;

                if (dopgs == 0) {
                        break;
                }

                pp2 = PP_PAGENEXT_N(pp2, curnpgs);
                if (((dopgs & (pg64k - 1)) == 0) && PP_ISMAPPED_LARGE(pp2)) {
                        cursz = fnd_mapping_sz(pp2);
                } else {
                        cursz = TTE8K;
                }
        }
}

/*
 * Returns 1 if page(s) can be converted from TNC to cacheable setting,
 * returns 0 otherwise. Note that oaddr argument is valid for only
 * 8k pages.
 */
int
tst_tnc(page_t *pp, pgcnt_t npages)
{
        struct  sf_hment *sfhme;
        struct  hme_blk *hmeblkp;
        tte_t   tte;
        caddr_t vaddr;
        int     clr_valid = 0;
        int     color, color1, bcolor;
        int     i, ncolors;

        ASSERT(pp != NULL);
        ASSERT(!(cache & CACHE_WRITEBACK));

        if (npages > 1) {
                ncolors = CACHE_NUM_COLOR;
        }

        for (i = 0; i < npages; i++) {
                ASSERT(sfmmu_mlist_held(pp));
                ASSERT(PP_ISTNC(pp));
                ASSERT(PP_GET_VCOLOR(pp) == NO_VCOLOR);

                if (PP_ISPNC(pp)) {
                        return (0);
                }

                clr_valid = 0;
                if (PP_ISMAPPED_KPM(pp)) {
                        caddr_t kpmvaddr;

                        ASSERT(kpm_enable);
                        kpmvaddr = hat_kpm_page2va(pp, 1);
                        ASSERT(!(npages > 1 && IS_KPM_ALIAS_RANGE(kpmvaddr)));
                        color1 = addr_to_vcolor(kpmvaddr);
                        clr_valid = 1;
                }

                for (sfhme = pp->p_mapping; sfhme; sfhme = sfhme->hme_next) {
                        if (IS_PAHME(sfhme))
                                continue;
                        hmeblkp = sfmmu_hmetohblk(sfhme);

                        sfmmu_copytte(&sfhme->hme_tte, &tte);
                        ASSERT(TTE_IS_VALID(&tte));

                        vaddr = tte_to_vaddr(hmeblkp, tte);
                        color = addr_to_vcolor(vaddr);

                        if (npages > 1) {
                                /*
                                 * If there is a big mapping, make sure
                                 * 8K mapping is consistent with the big
                                 * mapping.
                                 */
                                bcolor = i % ncolors;
                                if (color != bcolor) {
                                        return (0);
                                }
                        }
                        if (!clr_valid) {
                                clr_valid = 1;
                                color1 = color;
                        }

                        if (color1 != color) {
                                return (0);
                        }
                }

                pp = PP_PAGENEXT(pp);
        }

        return (1);
}

void
sfmmu_page_cache_array(page_t *pp, int flags, int cache_flush_flag,
    pgcnt_t npages)
{
        kmutex_t *pmtx;
        int i, ncolors, bcolor;
        kpm_hlk_t *kpmp;
        cpuset_t cpuset;

        ASSERT(pp != NULL);
        ASSERT(!(cache & CACHE_WRITEBACK));

        kpmp = sfmmu_kpm_kpmp_enter(pp, npages);
        pmtx = sfmmu_page_enter(pp);

        /*
         * Fast path caching single unmapped page
         */
        if (npages == 1 && !PP_ISMAPPED(pp) && !PP_ISMAPPED_KPM(pp) &&
            flags == HAT_CACHE) {
                PP_CLRTNC(pp);
                PP_CLRPNC(pp);
                sfmmu_page_exit(pmtx);
                sfmmu_kpm_kpmp_exit(kpmp);
                return;
        }

        /*
         * We need to capture all cpus in order to change cacheability
         * because we can't allow one cpu to access the same physical
         * page using a cacheable and a non-cachebale mapping at the same
         * time. Since we may end up walking the ism mapping list
         * have to grab it's lock now since we can't after all the
         * cpus have been captured.
         */
        sfmmu_hat_lock_all();
        mutex_enter(&ism_mlist_lock);
        kpreempt_disable();
        cpuset = cpu_ready_set;
        xc_attention(cpuset);

        if (npages > 1) {
                /*
                 * Make sure all colors are flushed since the
                 * sfmmu_page_cache() only flushes one color-
                 * it does not know big pages.
                 */
                ncolors = CACHE_NUM_COLOR;
                if (flags & HAT_TMPNC) {
                        for (i = 0; i < ncolors; i++) {
                                sfmmu_cache_flushcolor(i, pp->p_pagenum);
                        }
                        cache_flush_flag = CACHE_NO_FLUSH;
                }
        }

        for (i = 0; i < npages; i++) {

                ASSERT(sfmmu_mlist_held(pp));

                if (!(flags == HAT_TMPNC && PP_ISTNC(pp))) {

                        if (npages > 1) {
                                bcolor = i % ncolors;
                        } else {
                                bcolor = NO_VCOLOR;
                        }

                        sfmmu_page_cache(pp, flags, cache_flush_flag,
                            bcolor);
                }

                pp = PP_PAGENEXT(pp);
        }

        xt_sync(cpuset);
        xc_dismissed(cpuset);
        mutex_exit(&ism_mlist_lock);
        sfmmu_hat_unlock_all();
        sfmmu_page_exit(pmtx);
        sfmmu_kpm_kpmp_exit(kpmp);
        kpreempt_enable();
}

/*
 * This function changes the virtual cacheability of all mappings to a
 * particular page.  When changing from uncache to cacheable the mappings will
 * only be changed if all of them have the same virtual color.
 * We need to flush the cache in all cpus.  It is possible that
 * a process referenced a page as cacheable but has sinced exited
 * and cleared the mapping list.  We still to flush it but have no
 * state so all cpus is the only alternative.
 */
static void
sfmmu_page_cache(page_t *pp, int flags, int cache_flush_flag, int bcolor)
{
        struct  sf_hment *sfhme;
        struct  hme_blk *hmeblkp;
        sfmmu_t *sfmmup;
        tte_t   tte, ttemod;
        caddr_t vaddr;
        int     ret, color;
        pfn_t   pfn;

        color = bcolor;
        pfn = pp->p_pagenum;

        for (sfhme = pp->p_mapping; sfhme; sfhme = sfhme->hme_next) {

                if (IS_PAHME(sfhme))
                        continue;
                hmeblkp = sfmmu_hmetohblk(sfhme);

                sfmmu_copytte(&sfhme->hme_tte, &tte);
                ASSERT(TTE_IS_VALID(&tte));
                vaddr = tte_to_vaddr(hmeblkp, tte);
                color = addr_to_vcolor(vaddr);

#ifdef DEBUG
                if ((flags & HAT_CACHE) && bcolor != NO_VCOLOR) {
                        ASSERT(color == bcolor);
                }
#endif

                ASSERT(flags != HAT_TMPNC || color == PP_GET_VCOLOR(pp));

                ttemod = tte;
                if (flags & (HAT_UNCACHE | HAT_TMPNC)) {
                        TTE_CLR_VCACHEABLE(&ttemod);
                } else {        /* flags & HAT_CACHE */
                        TTE_SET_VCACHEABLE(&ttemod);
                }
                ret = sfmmu_modifytte_try(&tte, &ttemod, &sfhme->hme_tte);
                if (ret < 0) {
                        /*
                         * Since all cpus are captured modifytte should not
                         * fail.
                         */
                        panic("sfmmu_page_cache: write to tte failed");
                }

                sfmmup = hblktosfmmu(hmeblkp);
                if (cache_flush_flag == CACHE_FLUSH) {
                        /*
                         * Flush TSBs, TLBs and caches
                         */
                        if (hmeblkp->hblk_shared) {
                                sf_srd_t *srdp = (sf_srd_t *)sfmmup;
                                uint_t rid = hmeblkp->hblk_tag.htag_rid;
                                sf_region_t *rgnp;
                                ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                                ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                                ASSERT(srdp != NULL);
                                rgnp = srdp->srd_hmergnp[rid];
                                SFMMU_VALIDATE_SHAREDHBLK(hmeblkp,
                                    srdp, rgnp, rid);
                                (void) sfmmu_rgntlb_demap(vaddr, rgnp,
                                    hmeblkp, 0);
                                sfmmu_cache_flush(pfn, addr_to_vcolor(vaddr));
                        } else if (sfmmup->sfmmu_ismhat) {
                                if (flags & HAT_CACHE) {
                                        SFMMU_STAT(sf_ism_recache);
                                } else {
                                        SFMMU_STAT(sf_ism_uncache);
                                }
                                sfmmu_ismtlbcache_demap(vaddr, sfmmup, hmeblkp,
                                    pfn, CACHE_FLUSH);
                        } else {
                                sfmmu_tlbcache_demap(vaddr, sfmmup, hmeblkp,
                                    pfn, 0, FLUSH_ALL_CPUS, CACHE_FLUSH, 1);
                        }

                        /*
                         * all cache entries belonging to this pfn are
                         * now flushed.
                         */
                        cache_flush_flag = CACHE_NO_FLUSH;
                } else {
                        /*
                         * Flush only TSBs and TLBs.
                         */
                        if (hmeblkp->hblk_shared) {
                                sf_srd_t *srdp = (sf_srd_t *)sfmmup;
                                uint_t rid = hmeblkp->hblk_tag.htag_rid;
                                sf_region_t *rgnp;
                                ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                                ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                                ASSERT(srdp != NULL);
                                rgnp = srdp->srd_hmergnp[rid];
                                SFMMU_VALIDATE_SHAREDHBLK(hmeblkp,
                                    srdp, rgnp, rid);
                                (void) sfmmu_rgntlb_demap(vaddr, rgnp,
                                    hmeblkp, 0);
                        } else if (sfmmup->sfmmu_ismhat) {
                                if (flags & HAT_CACHE) {
                                        SFMMU_STAT(sf_ism_recache);
                                } else {
                                        SFMMU_STAT(sf_ism_uncache);
                                }
                                sfmmu_ismtlbcache_demap(vaddr, sfmmup, hmeblkp,
                                    pfn, CACHE_NO_FLUSH);
                        } else {
                                sfmmu_tlb_demap(vaddr, sfmmup, hmeblkp, 0, 1);
                        }
                }
        }

        if (PP_ISMAPPED_KPM(pp))
                sfmmu_kpm_page_cache(pp, flags, cache_flush_flag);

        switch (flags) {

                default:
                        panic("sfmmu_pagecache: unknown flags");
                        break;

                case HAT_CACHE:
                        PP_CLRTNC(pp);
                        PP_CLRPNC(pp);
                        PP_SET_VCOLOR(pp, color);
                        break;

                case HAT_TMPNC:
                        PP_SETTNC(pp);
                        PP_SET_VCOLOR(pp, NO_VCOLOR);
                        break;

                case HAT_UNCACHE:
                        PP_SETPNC(pp);
                        PP_CLRTNC(pp);
                        PP_SET_VCOLOR(pp, NO_VCOLOR);
                        break;
        }
}
#endif  /* VAC */


/*
 * Wrapper routine used to return a context.
 *
 * It's the responsibility of the caller to guarantee that the
 * process serializes on calls here by taking the HAT lock for
 * the hat.
 *
 */
static void
sfmmu_get_ctx(sfmmu_t *sfmmup)
{
        mmu_ctx_t *mmu_ctxp;
        uint_t pstate_save;
        int ret;

        ASSERT(sfmmu_hat_lock_held(sfmmup));
        ASSERT(sfmmup != ksfmmup);

        if (SFMMU_FLAGS_ISSET(sfmmup, HAT_ALLCTX_INVALID)) {
                sfmmu_setup_tsbinfo(sfmmup);
                SFMMU_FLAGS_CLEAR(sfmmup, HAT_ALLCTX_INVALID);
        }

        kpreempt_disable();

        mmu_ctxp = CPU_MMU_CTXP(CPU);
        ASSERT(mmu_ctxp);
        ASSERT(mmu_ctxp->mmu_idx < max_mmu_ctxdoms);
        ASSERT(mmu_ctxp == mmu_ctxs_tbl[mmu_ctxp->mmu_idx]);

        /*
         * Do a wrap-around if cnum reaches the max # cnum supported by a MMU.
         */
        if (mmu_ctxp->mmu_cnum == mmu_ctxp->mmu_nctxs)
                sfmmu_ctx_wrap_around(mmu_ctxp, B_TRUE);

        /*
         * Let the MMU set up the page sizes to use for
         * this context in the TLB. Don't program 2nd dtlb for ism hat.
         */
        if ((&mmu_set_ctx_page_sizes) && (sfmmup->sfmmu_ismhat == 0)) {
                mmu_set_ctx_page_sizes(sfmmup);
        }

        /*
         * sfmmu_alloc_ctx and sfmmu_load_mmustate will be performed with
         * interrupts disabled to prevent race condition with wrap-around
         * ctx invalidatation. In sun4v, ctx invalidation also involves
         * a HV call to set the number of TSBs to 0. If interrupts are not
         * disabled until after sfmmu_load_mmustate is complete TSBs may
         * become assigned to INVALID_CONTEXT. This is not allowed.
         */
        pstate_save = sfmmu_disable_intrs();

        if (sfmmu_alloc_ctx(sfmmup, 1, CPU, SFMMU_PRIVATE) &&
            sfmmup->sfmmu_scdp != NULL) {
                sf_scd_t *scdp = sfmmup->sfmmu_scdp;
                sfmmu_t *scsfmmup = scdp->scd_sfmmup;
                ret = sfmmu_alloc_ctx(scsfmmup, 1, CPU, SFMMU_SHARED);
                /* debug purpose only */
                ASSERT(!ret || scsfmmup->sfmmu_ctxs[CPU_MMU_IDX(CPU)].cnum
                    != INVALID_CONTEXT);
        }
        sfmmu_load_mmustate(sfmmup);

        sfmmu_enable_intrs(pstate_save);

        kpreempt_enable();
}

/*
 * When all cnums are used up in a MMU, cnum will wrap around to the
 * next generation and start from 2.
 */
static void
sfmmu_ctx_wrap_around(mmu_ctx_t *mmu_ctxp, boolean_t reset_cnum)
{

        /* caller must have disabled the preemption */
        ASSERT(curthread->t_preempt >= 1);
        ASSERT(mmu_ctxp != NULL);

        /* acquire Per-MMU (PM) spin lock */
        mutex_enter(&mmu_ctxp->mmu_lock);

        /* re-check to see if wrap-around is needed */
        if (mmu_ctxp->mmu_cnum < mmu_ctxp->mmu_nctxs)
                goto done;

        SFMMU_MMU_STAT(mmu_wrap_around);

        /* update gnum */
        ASSERT(mmu_ctxp->mmu_gnum != 0);
        mmu_ctxp->mmu_gnum++;
        if (mmu_ctxp->mmu_gnum == 0 ||
            mmu_ctxp->mmu_gnum > MAX_SFMMU_GNUM_VAL) {
                cmn_err(CE_PANIC, "mmu_gnum of mmu_ctx 0x%p is out of bound.",
                    (void *)mmu_ctxp);
        }

        if (mmu_ctxp->mmu_ncpus > 1) {
                cpuset_t cpuset;

                membar_enter(); /* make sure updated gnum visible */

                SFMMU_XCALL_STATS(NULL);

                /* xcall to others on the same MMU to invalidate ctx */
                cpuset = mmu_ctxp->mmu_cpuset;
                ASSERT(CPU_IN_SET(cpuset, CPU->cpu_id) || !reset_cnum);
                CPUSET_DEL(cpuset, CPU->cpu_id);
                CPUSET_AND(cpuset, cpu_ready_set);

                /*
                 * Pass in INVALID_CONTEXT as the first parameter to
                 * sfmmu_raise_tsb_exception, which invalidates the context
                 * of any process running on the CPUs in the MMU.
                 */
                xt_some(cpuset, sfmmu_raise_tsb_exception,
                    INVALID_CONTEXT, INVALID_CONTEXT);
                xt_sync(cpuset);

                SFMMU_MMU_STAT(mmu_tsb_raise_exception);
        }

        if (sfmmu_getctx_sec() != INVALID_CONTEXT) {
                sfmmu_setctx_sec(INVALID_CONTEXT);
                sfmmu_clear_utsbinfo();
        }

        /*
         * No xcall is needed here. For sun4u systems all CPUs in context
         * domain share a single physical MMU therefore it's enough to flush
         * TLB on local CPU. On sun4v systems we use 1 global context
         * domain and flush all remote TLBs in sfmmu_raise_tsb_exception
         * handler. Note that vtag_flushall_uctxs() is called
         * for Ultra II machine, where the equivalent flushall functionality
         * is implemented in SW, and only user ctx TLB entries are flushed.
         */
        if (&vtag_flushall_uctxs != NULL) {
                vtag_flushall_uctxs();
        } else {
                vtag_flushall();
        }

        /* reset mmu cnum, skips cnum 0 and 1 */
        if (reset_cnum == B_TRUE)
                mmu_ctxp->mmu_cnum = NUM_LOCKED_CTXS;

done:
        mutex_exit(&mmu_ctxp->mmu_lock);
}


/*
 * For multi-threaded process, set the process context to INVALID_CONTEXT
 * so that it faults and reloads the MMU state from TL=0. For single-threaded
 * process, we can just load the MMU state directly without having to
 * set context invalid. Caller must hold the hat lock since we don't
 * acquire it here.
 */
static void
sfmmu_sync_mmustate(sfmmu_t *sfmmup)
{
        uint_t cnum;
        uint_t pstate_save;

        ASSERT(sfmmup != ksfmmup);
        ASSERT(sfmmu_hat_lock_held(sfmmup));

        kpreempt_disable();

        /*
         * We check whether the pass'ed-in sfmmup is the same as the
         * current running proc. This is to makes sure the current proc
         * stays single-threaded if it already is.
         */
        if ((sfmmup == curthread->t_procp->p_as->a_hat) &&
            (curthread->t_procp->p_lwpcnt == 1)) {
                /* single-thread */
                cnum = sfmmup->sfmmu_ctxs[CPU_MMU_IDX(CPU)].cnum;
                if (cnum != INVALID_CONTEXT) {
                        uint_t curcnum;
                        /*
                         * Disable interrupts to prevent race condition
                         * with sfmmu_ctx_wrap_around ctx invalidation.
                         * In sun4v, ctx invalidation involves setting
                         * TSB to NULL, hence, interrupts should be disabled
                         * untill after sfmmu_load_mmustate is completed.
                         */
                        pstate_save = sfmmu_disable_intrs();
                        curcnum = sfmmu_getctx_sec();
                        if (curcnum == cnum)
                                sfmmu_load_mmustate(sfmmup);
                        sfmmu_enable_intrs(pstate_save);
                        ASSERT(curcnum == cnum || curcnum == INVALID_CONTEXT);
                }
        } else {
                /*
                 * multi-thread
                 * or when sfmmup is not the same as the curproc.
                 */
                sfmmu_invalidate_ctx(sfmmup);
        }

        kpreempt_enable();
}


/*
 * Replace the specified TSB with a new TSB.  This function gets called when
 * we grow, shrink or swapin a TSB.  When swapping in a TSB (TSB_SWAPIN), the
 * TSB_FORCEALLOC flag may be used to force allocation of a minimum-sized TSB
 * (8K).
 *
 * Caller must hold the HAT lock, but should assume any tsb_info
 * pointers it has are no longer valid after calling this function.
 *
 * Return values:
 *      TSB_ALLOCFAIL   Failed to allocate a TSB, due to memory constraints
 *      TSB_LOSTRACE    HAT is busy, i.e. another thread is already doing
 *                      something to this tsbinfo/TSB
 *      TSB_SUCCESS     Operation succeeded
 */
static tsb_replace_rc_t
sfmmu_replace_tsb(sfmmu_t *sfmmup, struct tsb_info *old_tsbinfo, uint_t szc,
    hatlock_t *hatlockp, uint_t flags)
{
        struct tsb_info *new_tsbinfo = NULL;
        struct tsb_info *curtsb, *prevtsb;
        uint_t tte_sz_mask;
        int i;

        ASSERT(sfmmup != ksfmmup);
        ASSERT(sfmmup->sfmmu_ismhat == 0);
        ASSERT(sfmmu_hat_lock_held(sfmmup));
        ASSERT(szc <= tsb_max_growsize);

        if (SFMMU_FLAGS_ISSET(sfmmup, HAT_BUSY))
                return (TSB_LOSTRACE);

        /*
         * Find the tsb_info ahead of this one in the list, and
         * also make sure that the tsb_info passed in really
         * exists!
         */
        for (prevtsb = NULL, curtsb = sfmmup->sfmmu_tsb;
            curtsb != old_tsbinfo && curtsb != NULL;
            prevtsb = curtsb, curtsb = curtsb->tsb_next)
                ;
        ASSERT(curtsb != NULL);

        if (!(flags & TSB_SWAPIN) && SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPPED)) {
                /*
                 * The process is swapped out, so just set the new size
                 * code.  When it swaps back in, we'll allocate a new one
                 * of the new chosen size.
                 */
                curtsb->tsb_szc = szc;
                return (TSB_SUCCESS);
        }
        SFMMU_FLAGS_SET(sfmmup, HAT_BUSY);

        tte_sz_mask = old_tsbinfo->tsb_ttesz_mask;

        /*
         * All initialization is done inside of sfmmu_tsbinfo_alloc().
         * If we fail to allocate a TSB, exit.
         *
         * If tsb grows with new tsb size > 4M and old tsb size < 4M,
         * then try 4M slab after the initial alloc fails.
         *
         * If tsb swapin with tsb size > 4M, then try 4M after the
         * initial alloc fails.
         */
        sfmmu_hat_exit(hatlockp);
        if (sfmmu_tsbinfo_alloc(&new_tsbinfo, szc,
            tte_sz_mask, flags, sfmmup) &&
            (!(flags & (TSB_GROW | TSB_SWAPIN)) || (szc <= TSB_4M_SZCODE) ||
            (!(flags & TSB_SWAPIN) &&
            (old_tsbinfo->tsb_szc >= TSB_4M_SZCODE)) ||
            sfmmu_tsbinfo_alloc(&new_tsbinfo, TSB_4M_SZCODE,
            tte_sz_mask, flags, sfmmup))) {
                (void) sfmmu_hat_enter(sfmmup);
                if (!(flags & TSB_SWAPIN))
                        SFMMU_STAT(sf_tsb_resize_failures);
                SFMMU_FLAGS_CLEAR(sfmmup, HAT_BUSY);
                return (TSB_ALLOCFAIL);
        }
        (void) sfmmu_hat_enter(sfmmup);

        /*
         * Re-check to make sure somebody else didn't muck with us while we
         * didn't hold the HAT lock.  If the process swapped out, fine, just
         * exit; this can happen if we try to shrink the TSB from the context
         * of another process (such as on an ISM unmap), though it is rare.
         */
        if (!(flags & TSB_SWAPIN) && SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPPED)) {
                SFMMU_STAT(sf_tsb_resize_failures);
                SFMMU_FLAGS_CLEAR(sfmmup, HAT_BUSY);
                sfmmu_hat_exit(hatlockp);
                sfmmu_tsbinfo_free(new_tsbinfo);
                (void) sfmmu_hat_enter(sfmmup);
                return (TSB_LOSTRACE);
        }

#ifdef  DEBUG
        /* Reverify that the tsb_info still exists.. for debugging only */
        for (prevtsb = NULL, curtsb = sfmmup->sfmmu_tsb;
            curtsb != old_tsbinfo && curtsb != NULL;
            prevtsb = curtsb, curtsb = curtsb->tsb_next)
                ;
        ASSERT(curtsb != NULL);
#endif  /* DEBUG */

        /*
         * Quiesce any CPUs running this process on their next TLB miss
         * so they atomically see the new tsb_info.  We temporarily set the
         * context to invalid context so new threads that come on processor
         * after we do the xcall to cpusran will also serialize behind the
         * HAT lock on TLB miss and will see the new TSB.  Since this short
         * race with a new thread coming on processor is relatively rare,
         * this synchronization mechanism should be cheaper than always
         * pausing all CPUs for the duration of the setup, which is what
         * the old implementation did.  This is particuarly true if we are
         * copying a huge chunk of memory around during that window.
         *
         * The memory barriers are to make sure things stay consistent
         * with resume() since it does not hold the HAT lock while
         * walking the list of tsb_info structures.
         */
        if ((flags & TSB_SWAPIN) != TSB_SWAPIN) {
                /* The TSB is either growing or shrinking. */
                sfmmu_invalidate_ctx(sfmmup);
        } else {
                /*
                 * It is illegal to swap in TSBs from a process other
                 * than a process being swapped in.  This in turn
                 * implies we do not have a valid MMU context here
                 * since a process needs one to resolve translation
                 * misses.
                 */
                ASSERT(curthread->t_procp->p_as->a_hat == sfmmup);
        }

#ifdef DEBUG
        ASSERT(max_mmu_ctxdoms > 0);

        /*
         * Process should have INVALID_CONTEXT on all MMUs
         */
        for (i = 0; i < max_mmu_ctxdoms; i++) {

                ASSERT(sfmmup->sfmmu_ctxs[i].cnum == INVALID_CONTEXT);
        }
#endif

        new_tsbinfo->tsb_next = old_tsbinfo->tsb_next;
        membar_stst();  /* strict ordering required */
        if (prevtsb)
                prevtsb->tsb_next = new_tsbinfo;
        else
                sfmmup->sfmmu_tsb = new_tsbinfo;
        membar_enter(); /* make sure new TSB globally visible */

        /*
         * We need to migrate TSB entries from the old TSB to the new TSB
         * if tsb_remap_ttes is set and the TSB is growing.
         */
        if (tsb_remap_ttes && ((flags & TSB_GROW) == TSB_GROW))
                sfmmu_copy_tsb(old_tsbinfo, new_tsbinfo);

        SFMMU_FLAGS_CLEAR(sfmmup, HAT_BUSY);

        /*
         * Drop the HAT lock to free our old tsb_info.
         */
        sfmmu_hat_exit(hatlockp);

        if ((flags & TSB_GROW) == TSB_GROW) {
                SFMMU_STAT(sf_tsb_grow);
        } else if ((flags & TSB_SHRINK) == TSB_SHRINK) {
                SFMMU_STAT(sf_tsb_shrink);
        }

        sfmmu_tsbinfo_free(old_tsbinfo);

        (void) sfmmu_hat_enter(sfmmup);
        return (TSB_SUCCESS);
}

/*
 * This function will re-program hat pgsz array, and invalidate the
 * process' context, forcing the process to switch to another
 * context on the next TLB miss, and therefore start using the
 * TLB that is reprogrammed for the new page sizes.
 */
void
sfmmu_reprog_pgsz_arr(sfmmu_t *sfmmup, uint8_t *tmp_pgsz)
{
        int i;
        hatlock_t *hatlockp = NULL;

        hatlockp = sfmmu_hat_enter(sfmmup);
        /* USIII+-IV+ optimization, requires hat lock */
        if (tmp_pgsz) {
                for (i = 0; i < mmu_page_sizes; i++)
                        sfmmup->sfmmu_pgsz[i] = tmp_pgsz[i];
        }
        SFMMU_STAT(sf_tlb_reprog_pgsz);

        sfmmu_invalidate_ctx(sfmmup);

        sfmmu_hat_exit(hatlockp);
}

/*
 * The scd_rttecnt field in the SCD must be updated to take account of the
 * regions which it contains.
 */
static void
sfmmu_set_scd_rttecnt(sf_srd_t *srdp, sf_scd_t *scdp)
{
        uint_t rid;
        uint_t i, j;
        ulong_t w;
        sf_region_t *rgnp;

        ASSERT(srdp != NULL);

        for (i = 0; i < SFMMU_HMERGNMAP_WORDS; i++) {
                if ((w = scdp->scd_region_map.bitmap[i]) == 0) {
                        continue;
                }

                j = 0;
                while (w) {
                        if (!(w & 0x1)) {
                                j++;
                                w >>= 1;
                                continue;
                        }
                        rid = (i << BT_ULSHIFT) | j;
                        j++;
                        w >>= 1;

                        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                        ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                        rgnp = srdp->srd_hmergnp[rid];
                        ASSERT(rgnp->rgn_refcnt > 0);
                        ASSERT(rgnp->rgn_id == rid);

                        scdp->scd_rttecnt[rgnp->rgn_pgszc] +=
                            rgnp->rgn_size >> TTE_PAGE_SHIFT(rgnp->rgn_pgszc);

                        /*
                         * Maintain the tsb0 inflation cnt for the regions
                         * in the SCD.
                         */
                        if (rgnp->rgn_pgszc >= TTE4M) {
                                scdp->scd_sfmmup->sfmmu_tsb0_4minflcnt +=
                                    rgnp->rgn_size >>
                                    (TTE_PAGE_SHIFT(TTE8K) + 2);
                        }
                }
        }
}

/*
 * This function assumes that there are either four or six supported page
 * sizes and at most two programmable TLBs, so we need to decide which
 * page sizes are most important and then tell the MMU layer so it
 * can adjust the TLB page sizes accordingly (if supported).
 *
 * If these assumptions change, this function will need to be
 * updated to support whatever the new limits are.
 *
 * The growing flag is nonzero if we are growing the address space,
 * and zero if it is shrinking.  This allows us to decide whether
 * to grow or shrink our TSB, depending upon available memory
 * conditions.
 */
static void
sfmmu_check_page_sizes(sfmmu_t *sfmmup, int growing)
{
        uint64_t ttecnt[MMU_PAGE_SIZES];
        uint64_t tte8k_cnt, tte4m_cnt;
        uint8_t i;
        int sectsb_thresh;

        /*
         * Kernel threads, processes with small address spaces not using
         * large pages, and dummy ISM HATs need not apply.
         */
        if (sfmmup == ksfmmup || sfmmup->sfmmu_ismhat != 0)
                return;

        if (!SFMMU_LGPGS_INUSE(sfmmup) &&
            sfmmup->sfmmu_ttecnt[TTE8K] <= tsb_rss_factor)
                return;

        for (i = 0; i < mmu_page_sizes; i++) {
                ttecnt[i] = sfmmup->sfmmu_ttecnt[i] +
                    sfmmup->sfmmu_ismttecnt[i];
        }

        /* Check pagesizes in use, and possibly reprogram DTLB. */
        if (&mmu_check_page_sizes)
                mmu_check_page_sizes(sfmmup, ttecnt);

        /*
         * Calculate the number of 8k ttes to represent the span of these
         * pages.
         */
        tte8k_cnt = ttecnt[TTE8K] +
            (ttecnt[TTE64K] << (MMU_PAGESHIFT64K - MMU_PAGESHIFT)) +
            (ttecnt[TTE512K] << (MMU_PAGESHIFT512K - MMU_PAGESHIFT));
        if (mmu_page_sizes == max_mmu_page_sizes) {
                tte4m_cnt = ttecnt[TTE4M] +
                    (ttecnt[TTE32M] << (MMU_PAGESHIFT32M - MMU_PAGESHIFT4M)) +
                    (ttecnt[TTE256M] << (MMU_PAGESHIFT256M - MMU_PAGESHIFT4M));
        } else {
                tte4m_cnt = ttecnt[TTE4M];
        }

        /*
         * Inflate tte8k_cnt to allow for region large page allocation failure.
         */
        tte8k_cnt += sfmmup->sfmmu_tsb0_4minflcnt;

        /*
         * Inflate TSB sizes by a factor of 2 if this process
         * uses 4M text pages to minimize extra conflict misses
         * in the first TSB since without counting text pages
         * 8K TSB may become too small.
         *
         * Also double the size of the second TSB to minimize
         * extra conflict misses due to competition between 4M text pages
         * and data pages.
         *
         * We need to adjust the second TSB allocation threshold by the
         * inflation factor, since there is no point in creating a second
         * TSB when we know all the mappings can fit in the I/D TLBs.
         */
        sectsb_thresh = tsb_sectsb_threshold;
        if (sfmmup->sfmmu_flags & HAT_4MTEXT_FLAG) {
                tte8k_cnt <<= 1;
                tte4m_cnt <<= 1;
                sectsb_thresh <<= 1;
        }

        /*
         * Check to see if our TSB is the right size; we may need to
         * grow or shrink it.  If the process is small, our work is
         * finished at this point.
         */
        if (tte8k_cnt <= tsb_rss_factor && tte4m_cnt <= sectsb_thresh) {
                return;
        }
        sfmmu_size_tsb(sfmmup, growing, tte8k_cnt, tte4m_cnt, sectsb_thresh);
}

static void
sfmmu_size_tsb(sfmmu_t *sfmmup, int growing, uint64_t tte8k_cnt,
    uint64_t tte4m_cnt, int sectsb_thresh)
{
        int tsb_bits;
        uint_t tsb_szc;
        struct tsb_info *tsbinfop;
        hatlock_t *hatlockp = NULL;

        hatlockp = sfmmu_hat_enter(sfmmup);
        ASSERT(hatlockp != NULL);
        tsbinfop = sfmmup->sfmmu_tsb;
        ASSERT(tsbinfop != NULL);

        /*
         * If we're growing, select the size based on RSS.  If we're
         * shrinking, leave some room so we don't have to turn around and
         * grow again immediately.
         */
        if (growing)
                tsb_szc = SELECT_TSB_SIZECODE(tte8k_cnt);
        else
                tsb_szc = SELECT_TSB_SIZECODE(tte8k_cnt << 1);

        if (!growing && (tsb_szc < tsbinfop->tsb_szc) &&
            (tsb_szc >= default_tsb_size) && TSB_OK_SHRINK()) {
                (void) sfmmu_replace_tsb(sfmmup, tsbinfop, tsb_szc,
                    hatlockp, TSB_SHRINK);
        } else if (growing && tsb_szc > tsbinfop->tsb_szc && TSB_OK_GROW()) {
                (void) sfmmu_replace_tsb(sfmmup, tsbinfop, tsb_szc,
                    hatlockp, TSB_GROW);
        }
        tsbinfop = sfmmup->sfmmu_tsb;

        /*
         * With the TLB and first TSB out of the way, we need to see if
         * we need a second TSB for 4M pages.  If we managed to reprogram
         * the TLB page sizes above, the process will start using this new
         * TSB right away; otherwise, it will start using it on the next
         * context switch.  Either way, it's no big deal so there's no
         * synchronization with the trap handlers here unless we grow the
         * TSB (in which case it's required to prevent using the old one
         * after it's freed). Note: second tsb is required for 32M/256M
         * page sizes.
         */
        if (tte4m_cnt > sectsb_thresh) {
                /*
                 * If we're growing, select the size based on RSS.  If we're
                 * shrinking, leave some room so we don't have to turn
                 * around and grow again immediately.
                 */
                if (growing)
                        tsb_szc = SELECT_TSB_SIZECODE(tte4m_cnt);
                else
                        tsb_szc = SELECT_TSB_SIZECODE(tte4m_cnt << 1);
                if (tsbinfop->tsb_next == NULL) {
                        struct tsb_info *newtsb;
                        int allocflags = SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPPED)?
                            0 : TSB_ALLOC;

                        sfmmu_hat_exit(hatlockp);

                        /*
                         * Try to allocate a TSB for 4[32|256]M pages.  If we
                         * can't get the size we want, retry w/a minimum sized
                         * TSB.  If that still didn't work, give up; we can
                         * still run without one.
                         */
                        tsb_bits = (mmu_page_sizes == max_mmu_page_sizes)?
                            TSB4M|TSB32M|TSB256M:TSB4M;
                        if ((sfmmu_tsbinfo_alloc(&newtsb, tsb_szc, tsb_bits,
                            allocflags, sfmmup)) &&
                            (tsb_szc <= TSB_4M_SZCODE ||
                            sfmmu_tsbinfo_alloc(&newtsb, TSB_4M_SZCODE,
                            tsb_bits, allocflags, sfmmup)) &&
                            sfmmu_tsbinfo_alloc(&newtsb, TSB_MIN_SZCODE,
                            tsb_bits, allocflags, sfmmup)) {
                                return;
                        }

                        hatlockp = sfmmu_hat_enter(sfmmup);

                        sfmmu_invalidate_ctx(sfmmup);

                        if (sfmmup->sfmmu_tsb->tsb_next == NULL) {
                                sfmmup->sfmmu_tsb->tsb_next = newtsb;
                                SFMMU_STAT(sf_tsb_sectsb_create);
                                sfmmu_hat_exit(hatlockp);
                                return;
                        } else {
                                /*
                                 * It's annoying, but possible for us
                                 * to get here.. we dropped the HAT lock
                                 * because of locking order in the kmem
                                 * allocator, and while we were off getting
                                 * our memory, some other thread decided to
                                 * do us a favor and won the race to get a
                                 * second TSB for this process.  Sigh.
                                 */
                                sfmmu_hat_exit(hatlockp);
                                sfmmu_tsbinfo_free(newtsb);
                                return;
                        }
                }

                /*
                 * We have a second TSB, see if it's big enough.
                 */
                tsbinfop = tsbinfop->tsb_next;

                /*
                 * Check to see if our second TSB is the right size;
                 * we may need to grow or shrink it.
                 * To prevent thrashing (e.g. growing the TSB on a
                 * subsequent map operation), only try to shrink if
                 * the TSB reach exceeds twice the virtual address
                 * space size.
                 */
                if (!growing && (tsb_szc < tsbinfop->tsb_szc) &&
                    (tsb_szc >= default_tsb_size) && TSB_OK_SHRINK()) {
                        (void) sfmmu_replace_tsb(sfmmup, tsbinfop,
                            tsb_szc, hatlockp, TSB_SHRINK);
                } else if (growing && tsb_szc > tsbinfop->tsb_szc &&
                    TSB_OK_GROW()) {
                        (void) sfmmu_replace_tsb(sfmmup, tsbinfop,
                            tsb_szc, hatlockp, TSB_GROW);
                }
        }

        sfmmu_hat_exit(hatlockp);
}

/*
 * Free up a sfmmu
 * Since the sfmmu is currently embedded in the hat struct we simply zero
 * out our fields and free up the ism map blk list if any.
 */
static void
sfmmu_free_sfmmu(sfmmu_t *sfmmup)
{
        ism_blk_t       *blkp, *nx_blkp;
#ifdef  DEBUG
        ism_map_t       *map;
        int             i;
#endif

        ASSERT(sfmmup->sfmmu_ttecnt[TTE8K] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE64K] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE512K] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE4M] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE32M] == 0);
        ASSERT(sfmmup->sfmmu_ttecnt[TTE256M] == 0);
        ASSERT(SF_RGNMAP_ISNULL(sfmmup));

        sfmmup->sfmmu_free = 0;
        sfmmup->sfmmu_ismhat = 0;

        blkp = sfmmup->sfmmu_iblk;
        sfmmup->sfmmu_iblk = NULL;

        while (blkp) {
#ifdef  DEBUG
                map = blkp->iblk_maps;
                for (i = 0; i < ISM_MAP_SLOTS; i++) {
                        ASSERT(map[i].imap_seg == 0);
                        ASSERT(map[i].imap_ismhat == NULL);
                        ASSERT(map[i].imap_ment == NULL);
                }
#endif
                nx_blkp = blkp->iblk_next;
                blkp->iblk_next = NULL;
                blkp->iblk_nextpa = (uint64_t)-1;
                kmem_cache_free(ism_blk_cache, blkp);
                blkp = nx_blkp;
        }
}

/*
 * Locking primitves accessed by HATLOCK macros
 */

#define SFMMU_SPL_MTX   (0x0)
#define SFMMU_ML_MTX    (0x1)

#define SFMMU_MLSPL_MTX(type, pg)       (((type) == SFMMU_SPL_MTX) ? \
                                            SPL_HASH(pg) : MLIST_HASH(pg))

kmutex_t *
sfmmu_page_enter(struct page *pp)
{
        return (sfmmu_mlspl_enter(pp, SFMMU_SPL_MTX));
}

void
sfmmu_page_exit(kmutex_t *spl)
{
        mutex_exit(spl);
}

int
sfmmu_page_spl_held(struct page *pp)
{
        return (sfmmu_mlspl_held(pp, SFMMU_SPL_MTX));
}

kmutex_t *
sfmmu_mlist_enter(struct page *pp)
{
        return (sfmmu_mlspl_enter(pp, SFMMU_ML_MTX));
}

void
sfmmu_mlist_exit(kmutex_t *mml)
{
        mutex_exit(mml);
}

int
sfmmu_mlist_held(struct page *pp)
{

        return (sfmmu_mlspl_held(pp, SFMMU_ML_MTX));
}

/*
 * Common code for sfmmu_mlist_enter() and sfmmu_page_enter().  For
 * sfmmu_mlist_enter() case mml_table lock array is used and for
 * sfmmu_page_enter() sfmmu_page_lock lock array is used.
 *
 * The lock is taken on a root page so that it protects an operation on all
 * constituent pages of a large page pp belongs to.
 *
 * The routine takes a lock from the appropriate array. The lock is determined
 * by hashing the root page. After taking the lock this routine checks if the
 * root page has the same size code that was used to determine the root (i.e
 * that root hasn't changed).  If root page has the expected p_szc field we
 * have the right lock and it's returned to the caller. If root's p_szc
 * decreased we release the lock and retry from the beginning.  This case can
 * happen due to hat_page_demote() decreasing p_szc between our load of p_szc
 * value and taking the lock. The number of retries due to p_szc decrease is
 * limited by the maximum p_szc value. If p_szc is 0 we return the lock
 * determined by hashing pp itself.
 *
 * If our caller doesn't hold a SE_SHARED or SE_EXCL lock on pp it's also
 * possible that p_szc can increase. To increase p_szc a thread has to lock
 * all constituent pages EXCL and do hat_pageunload() on all of them. All the
 * callers that don't hold a page locked recheck if hmeblk through which pp
 * was found still maps this pp.  If it doesn't map it anymore returned lock
 * is immediately dropped. Therefore if sfmmu_mlspl_enter() hits the case of
 * p_szc increase after taking the lock it returns this lock without further
 * retries because in this case the caller doesn't care about which lock was
 * taken. The caller will drop it right away.
 *
 * After the routine returns it's guaranteed that hat_page_demote() can't
 * change p_szc field of any of constituent pages of a large page pp belongs
 * to as long as pp was either locked at least SHARED prior to this call or
 * the caller finds that hment that pointed to this pp still references this
 * pp (this also assumes that the caller holds hme hash bucket lock so that
 * the same pp can't be remapped into the same hmeblk after it was unmapped by
 * hat_pageunload()).
 */
static kmutex_t *
sfmmu_mlspl_enter(struct page *pp, int type)
{
        kmutex_t        *mtx;
        uint_t          prev_rszc = UINT_MAX;
        page_t          *rootpp;
        uint_t          szc;
        uint_t          rszc;
        uint_t          pszc = pp->p_szc;

        ASSERT(pp != NULL);

again:
        if (pszc == 0) {
                mtx = SFMMU_MLSPL_MTX(type, pp);
                mutex_enter(mtx);
                return (mtx);
        }

        /* The lock lives in the root page */
        rootpp = PP_GROUPLEADER(pp, pszc);
        mtx = SFMMU_MLSPL_MTX(type, rootpp);
        mutex_enter(mtx);

        /*
         * Return mml in the following 3 cases:
         *
         * 1) If pp itself is root since if its p_szc decreased before we took
         * the lock pp is still the root of smaller szc page. And if its p_szc
         * increased it doesn't matter what lock we return (see comment in
         * front of this routine).
         *
         * 2) If pp's not root but rootpp is the root of a rootpp->p_szc size
         * large page we have the right lock since any previous potential
         * hat_page_demote() is done demoting from greater than current root's
         * p_szc because hat_page_demote() changes root's p_szc last. No
         * further hat_page_demote() can start or be in progress since it
         * would need the same lock we currently hold.
         *
         * 3) If rootpp's p_szc increased since previous iteration it doesn't
         * matter what lock we return (see comment in front of this routine).
         */
        if (pp == rootpp || (rszc = rootpp->p_szc) == pszc ||
            rszc >= prev_rszc) {
                return (mtx);
        }

        /*
         * hat_page_demote() could have decreased root's p_szc.
         * In this case pp's p_szc must also be smaller than pszc.
         * Retry.
         */
        if (rszc < pszc) {
                szc = pp->p_szc;
                if (szc < pszc) {
                        mutex_exit(mtx);
                        pszc = szc;
                        goto again;
                }
                /*
                 * pp's p_szc increased after it was decreased.
                 * page cannot be mapped. Return current lock. The caller
                 * will drop it right away.
                 */
                return (mtx);
        }

        /*
         * root's p_szc is greater than pp's p_szc.
         * hat_page_demote() is not done with all pages
         * yet. Wait for it to complete.
         */
        mutex_exit(mtx);
        rootpp = PP_GROUPLEADER(rootpp, rszc);
        mtx = SFMMU_MLSPL_MTX(type, rootpp);
        mutex_enter(mtx);
        mutex_exit(mtx);
        prev_rszc = rszc;
        goto again;
}

static int
sfmmu_mlspl_held(struct page *pp, int type)
{
        kmutex_t        *mtx;

        ASSERT(pp != NULL);
        /* The lock lives in the root page */
        pp = PP_PAGEROOT(pp);
        ASSERT(pp != NULL);

        mtx = SFMMU_MLSPL_MTX(type, pp);
        return (MUTEX_HELD(mtx));
}

static uint_t
sfmmu_get_free_hblk(struct hme_blk **hmeblkpp, uint_t critical)
{
        struct  hme_blk *hblkp;


        if (freehblkp != NULL) {
                mutex_enter(&freehblkp_lock);
                if (freehblkp != NULL) {
                        /*
                         * If the current thread is owning hblk_reserve OR
                         * critical request from sfmmu_hblk_steal()
                         * let it succeed even if freehblkcnt is really low.
                         */
                        if (freehblkcnt <= HBLK_RESERVE_MIN && !critical) {
                                SFMMU_STAT(sf_get_free_throttle);
                                mutex_exit(&freehblkp_lock);
                                return (0);
                        }
                        freehblkcnt--;
                        *hmeblkpp = freehblkp;
                        hblkp = *hmeblkpp;
                        freehblkp = hblkp->hblk_next;
                        mutex_exit(&freehblkp_lock);
                        hblkp->hblk_next = NULL;
                        SFMMU_STAT(sf_get_free_success);

                        ASSERT(hblkp->hblk_hmecnt == 0);
                        ASSERT(hblkp->hblk_vcnt == 0);
                        ASSERT(hblkp->hblk_nextpa == va_to_pa((caddr_t)hblkp));

                        return (1);
                }
                mutex_exit(&freehblkp_lock);
        }

        /* Check cpu hblk pending queues */
        if ((*hmeblkpp = sfmmu_check_pending_hblks(TTE8K)) != NULL) {
                hblkp = *hmeblkpp;
                hblkp->hblk_next = NULL;
                hblkp->hblk_nextpa = va_to_pa((caddr_t)hblkp);

                ASSERT(hblkp->hblk_hmecnt == 0);
                ASSERT(hblkp->hblk_vcnt == 0);

                return (1);
        }

        SFMMU_STAT(sf_get_free_fail);
        return (0);
}

static uint_t
sfmmu_put_free_hblk(struct hme_blk *hmeblkp, uint_t critical)
{
        struct  hme_blk *hblkp;

        ASSERT(hmeblkp->hblk_hmecnt == 0);
        ASSERT(hmeblkp->hblk_vcnt == 0);
        ASSERT(hmeblkp->hblk_nextpa == va_to_pa((caddr_t)hmeblkp));

        /*
         * If the current thread is mapping into kernel space,
         * let it succede even if freehblkcnt is max
         * so that it will avoid freeing it to kmem.
         * This will prevent stack overflow due to
         * possible recursion since kmem_cache_free()
         * might require creation of a slab which
         * in turn needs an hmeblk to map that slab;
         * let's break this vicious chain at the first
         * opportunity.
         */
        if (freehblkcnt < HBLK_RESERVE_CNT || critical) {
                mutex_enter(&freehblkp_lock);
                if (freehblkcnt < HBLK_RESERVE_CNT || critical) {
                        SFMMU_STAT(sf_put_free_success);
                        freehblkcnt++;
                        hmeblkp->hblk_next = freehblkp;
                        freehblkp = hmeblkp;
                        mutex_exit(&freehblkp_lock);
                        return (1);
                }
                mutex_exit(&freehblkp_lock);
        }

        /*
         * Bring down freehblkcnt to HBLK_RESERVE_CNT. We are here
         * only if freehblkcnt is at least HBLK_RESERVE_CNT *and*
         * we are not in the process of mapping into kernel space.
         */
        ASSERT(!critical);
        while (freehblkcnt > HBLK_RESERVE_CNT) {
                mutex_enter(&freehblkp_lock);
                if (freehblkcnt > HBLK_RESERVE_CNT) {
                        freehblkcnt--;
                        hblkp = freehblkp;
                        freehblkp = hblkp->hblk_next;
                        mutex_exit(&freehblkp_lock);
                        ASSERT(get_hblk_cache(hblkp) == sfmmu8_cache);
                        kmem_cache_free(sfmmu8_cache, hblkp);
                        continue;
                }
                mutex_exit(&freehblkp_lock);
        }
        SFMMU_STAT(sf_put_free_fail);
        return (0);
}

static void
sfmmu_hblk_swap(struct hme_blk *new)
{
        struct hme_blk *old, *hblkp, *prev;
        uint64_t newpa;
        caddr_t base, vaddr, endaddr;
        struct hmehash_bucket *hmebp;
        struct sf_hment *osfhme, *nsfhme;
        page_t *pp;
        kmutex_t *pml;
        tte_t tte;
        struct hme_blk *list = NULL;

#ifdef  DEBUG
        hmeblk_tag              hblktag;
        struct hme_blk          *found;
#endif
        old = HBLK_RESERVE;
        ASSERT(!old->hblk_shared);

        /*
         * save pa before bcopy clobbers it
         */
        newpa = new->hblk_nextpa;

        base = (caddr_t)get_hblk_base(old);
        endaddr = base + get_hblk_span(old);

        /*
         * acquire hash bucket lock.
         */
        hmebp = sfmmu_tteload_acquire_hashbucket(ksfmmup, base, TTE8K,
            SFMMU_INVALID_SHMERID);

        /*
         * copy contents from old to new
         */
        bcopy((void *)old, (void *)new, HME8BLK_SZ);

        /*
         * add new to hash chain
         */
        sfmmu_hblk_hash_add(hmebp, new, newpa);

        /*
         * search hash chain for hblk_reserve; this needs to be performed
         * after adding new, otherwise prev won't correspond to the hblk which
         * is prior to old in hash chain when we call sfmmu_hblk_hash_rm to
         * remove old later.
         */
        for (prev = NULL,
            hblkp = hmebp->hmeblkp; hblkp != NULL && hblkp != old;
            prev = hblkp, hblkp = hblkp->hblk_next)
                ;

        if (hblkp != old)
                panic("sfmmu_hblk_swap: hblk_reserve not found");

        /*
         * p_mapping list is still pointing to hments in hblk_reserve;
         * fix up p_mapping list so that they point to hments in new.
         *
         * Since all these mappings are created by hblk_reserve_thread
         * on the way and it's using at least one of the buffers from each of
         * the newly minted slabs, there is no danger of any of these
         * mappings getting unloaded by another thread.
         *
         * tsbmiss could only modify ref/mod bits of hments in old/new.
         * Since all of these hments hold mappings established by segkmem
         * and mappings in segkmem are setup with HAT_NOSYNC, ref/mod bits
         * have no meaning for the mappings in hblk_reserve.  hments in
         * old and new are identical except for ref/mod bits.
         */
        for (vaddr = base; vaddr < endaddr; vaddr += TTEBYTES(TTE8K)) {

                HBLKTOHME(osfhme, old, vaddr);
                sfmmu_copytte(&osfhme->hme_tte, &tte);

                if (TTE_IS_VALID(&tte)) {
                        if ((pp = osfhme->hme_page) == NULL)
                                panic("sfmmu_hblk_swap: page not mapped");

                        pml = sfmmu_mlist_enter(pp);

                        if (pp != osfhme->hme_page)
                                panic("sfmmu_hblk_swap: mapping changed");

                        HBLKTOHME(nsfhme, new, vaddr);

                        HME_ADD(nsfhme, pp);
                        HME_SUB(osfhme, pp);

                        sfmmu_mlist_exit(pml);
                }
        }

        /*
         * remove old from hash chain
         */
        sfmmu_hblk_hash_rm(hmebp, old, prev, &list, 1);

#ifdef  DEBUG

        hblktag.htag_id = ksfmmup;
        hblktag.htag_rid = SFMMU_INVALID_SHMERID;
        hblktag.htag_bspage = HME_HASH_BSPAGE(base, HME_HASH_SHIFT(TTE8K));
        hblktag.htag_rehash = HME_HASH_REHASH(TTE8K);
        HME_HASH_FAST_SEARCH(hmebp, hblktag, found);

        if (found != new)
                panic("sfmmu_hblk_swap: new hblk not found");
#endif

        SFMMU_HASH_UNLOCK(hmebp);

        /*
         * Reset hblk_reserve
         */
        bzero((void *)old, HME8BLK_SZ);
        old->hblk_nextpa = va_to_pa((caddr_t)old);
}

/*
 * Grab the mlist mutex for both pages passed in.
 *
 * low and high will be returned as pointers to the mutexes for these pages.
 * low refers to the mutex residing in the lower bin of the mlist hash, while
 * high refers to the mutex residing in the higher bin of the mlist hash.  This
 * is due to the locking order restrictions on the same thread grabbing
 * multiple mlist mutexes.  The low lock must be acquired before the high lock.
 *
 * If both pages hash to the same mutex, only grab that single mutex, and
 * high will be returned as NULL
 * If the pages hash to different bins in the hash, grab the lower addressed
 * lock first and then the higher addressed lock in order to follow the locking
 * rules involved with the same thread grabbing multiple mlist mutexes.
 * low and high will both have non-NULL values.
 */
static void
sfmmu_mlist_reloc_enter(struct page *targ, struct page *repl,
    kmutex_t **low, kmutex_t **high)
{
        kmutex_t        *mml_targ, *mml_repl;

        /*
         * no need to do the dance around szc as in sfmmu_mlist_enter()
         * because this routine is only called by hat_page_relocate() and all
         * targ and repl pages are already locked EXCL so szc can't change.
         */

        mml_targ = MLIST_HASH(PP_PAGEROOT(targ));
        mml_repl = MLIST_HASH(PP_PAGEROOT(repl));

        if (mml_targ == mml_repl) {
                *low = mml_targ;
                *high = NULL;
        } else {
                if (mml_targ < mml_repl) {
                        *low = mml_targ;
                        *high = mml_repl;
                } else {
                        *low = mml_repl;
                        *high = mml_targ;
                }
        }

        mutex_enter(*low);
        if (*high)
                mutex_enter(*high);
}

static void
sfmmu_mlist_reloc_exit(kmutex_t *low, kmutex_t *high)
{
        if (high)
                mutex_exit(high);
        mutex_exit(low);
}

static hatlock_t *
sfmmu_hat_enter(sfmmu_t *sfmmup)
{
        hatlock_t       *hatlockp;

        if (sfmmup != ksfmmup) {
                hatlockp = TSB_HASH(sfmmup);
                mutex_enter(HATLOCK_MUTEXP(hatlockp));
                return (hatlockp);
        }
        return (NULL);
}

static hatlock_t *
sfmmu_hat_tryenter(sfmmu_t *sfmmup)
{
        hatlock_t       *hatlockp;

        if (sfmmup != ksfmmup) {
                hatlockp = TSB_HASH(sfmmup);
                if (mutex_tryenter(HATLOCK_MUTEXP(hatlockp)) == 0)
                        return (NULL);
                return (hatlockp);
        }
        return (NULL);
}

static void
sfmmu_hat_exit(hatlock_t *hatlockp)
{
        if (hatlockp != NULL)
                mutex_exit(HATLOCK_MUTEXP(hatlockp));
}

static void
sfmmu_hat_lock_all(void)
{
        int i;
        for (i = 0; i < SFMMU_NUM_LOCK; i++)
                mutex_enter(HATLOCK_MUTEXP(&hat_lock[i]));
}

static void
sfmmu_hat_unlock_all(void)
{
        int i;
        for (i = SFMMU_NUM_LOCK - 1; i >= 0; i--)
                mutex_exit(HATLOCK_MUTEXP(&hat_lock[i]));
}

int
sfmmu_hat_lock_held(sfmmu_t *sfmmup)
{
        ASSERT(sfmmup != ksfmmup);
        return (MUTEX_HELD(HATLOCK_MUTEXP(TSB_HASH(sfmmup))));
}

/*
 * Locking primitives to provide consistency between ISM unmap
 * and other operations.  Since ISM unmap can take a long time, we
 * use HAT_ISMBUSY flag (protected by the hatlock) to avoid creating
 * contention on the hatlock buckets while ISM segments are being
 * unmapped.  The tradeoff is that the flags don't prevent priority
 * inversion from occurring, so we must request kernel priority in
 * case we have to sleep to keep from getting buried while holding
 * the HAT_ISMBUSY flag set, which in turn could block other kernel
 * threads from running (for example, in sfmmu_uvatopfn()).
 */
static void
sfmmu_ismhat_enter(sfmmu_t *sfmmup, int hatlock_held)
{
        hatlock_t *hatlockp;

        if (!hatlock_held)
                hatlockp = sfmmu_hat_enter(sfmmup);
        while (SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY))
                cv_wait(&sfmmup->sfmmu_tsb_cv, HATLOCK_MUTEXP(hatlockp));
        SFMMU_FLAGS_SET(sfmmup, HAT_ISMBUSY);
        if (!hatlock_held)
                sfmmu_hat_exit(hatlockp);
}

static void
sfmmu_ismhat_exit(sfmmu_t *sfmmup, int hatlock_held)
{
        hatlock_t *hatlockp;

        if (!hatlock_held)
                hatlockp = sfmmu_hat_enter(sfmmup);
        ASSERT(SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY));
        SFMMU_FLAGS_CLEAR(sfmmup, HAT_ISMBUSY);
        cv_broadcast(&sfmmup->sfmmu_tsb_cv);
        if (!hatlock_held)
                sfmmu_hat_exit(hatlockp);
}

/*
 *
 * Algorithm:
 *
 * (1) if segkmem is not ready, allocate hblk from an array of pre-alloc'ed
 *      hblks.
 *
 * (2) if we are allocating an hblk for mapping a slab in sfmmu_cache,
 *
 *              (a) try to return an hblk from reserve pool of free hblks;
 *              (b) if the reserve pool is empty, acquire hblk_reserve_lock
 *                  and return hblk_reserve.
 *
 * (3) call kmem_cache_alloc() to allocate hblk;
 *
 *              (a) if hblk_reserve_lock is held by the current thread,
 *                  atomically replace hblk_reserve by the hblk that is
 *                  returned by kmem_cache_alloc; release hblk_reserve_lock
 *                  and call kmem_cache_alloc() again.
 *              (b) if reserve pool is not full, add the hblk that is
 *                  returned by kmem_cache_alloc to reserve pool and
 *                  call kmem_cache_alloc again.
 *
 */
static struct hme_blk *
sfmmu_hblk_alloc(sfmmu_t *sfmmup, caddr_t vaddr,
    struct hmehash_bucket *hmebp, uint_t size, hmeblk_tag hblktag,
    uint_t flags, uint_t rid)
{
        struct hme_blk *hmeblkp = NULL;
        struct hme_blk *newhblkp;
        struct hme_blk *shw_hblkp = NULL;
        struct kmem_cache *sfmmu_cache = NULL;
        uint64_t hblkpa;
        ulong_t index;
        uint_t owner;           /* set to 1 if using hblk_reserve */
        uint_t forcefree;
        int sleep;
        sf_srd_t *srdp;
        sf_region_t *rgnp;

        ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));
        ASSERT(hblktag.htag_rid == rid);
        SFMMU_VALIDATE_HMERID(sfmmup, rid, vaddr, TTEBYTES(size));
        ASSERT(!SFMMU_IS_SHMERID_VALID(rid) ||
            IS_P2ALIGNED(vaddr, TTEBYTES(size)));

        /*
         * If segkmem is not created yet, allocate from static hmeblks
         * created at the end of startup_modules().  See the block comment
         * in startup_modules() describing how we estimate the number of
         * static hmeblks that will be needed during re-map.
         */
        if (!hblk_alloc_dynamic) {

                ASSERT(!SFMMU_IS_SHMERID_VALID(rid));

                if (size == TTE8K) {
                        index = nucleus_hblk8.index;
                        if (index >= nucleus_hblk8.len) {
                                /*
                                 * If we panic here, see startup_modules() to
                                 * make sure that we are calculating the
                                 * number of hblk8's that we need correctly.
                                 */
                                prom_panic("no nucleus hblk8 to allocate");
                        }
                        hmeblkp =
                            (struct hme_blk *)&nucleus_hblk8.list[index];
                        nucleus_hblk8.index++;
                        SFMMU_STAT(sf_hblk8_nalloc);
                } else {
                        index = nucleus_hblk1.index;
                        if (nucleus_hblk1.index >= nucleus_hblk1.len) {
                                /*
                                 * If we panic here, see startup_modules().
                                 * Most likely you need to update the
                                 * calculation of the number of hblk1 elements
                                 * that the kernel needs to boot.
                                 */
                                prom_panic("no nucleus hblk1 to allocate");
                        }
                        hmeblkp =
                            (struct hme_blk *)&nucleus_hblk1.list[index];
                        nucleus_hblk1.index++;
                        SFMMU_STAT(sf_hblk1_nalloc);
                }

                goto hblk_init;
        }

        SFMMU_HASH_UNLOCK(hmebp);

        if (sfmmup != KHATID && !SFMMU_IS_SHMERID_VALID(rid)) {
                if (mmu_page_sizes == max_mmu_page_sizes) {
                        if (size < TTE256M)
                                shw_hblkp = sfmmu_shadow_hcreate(sfmmup, vaddr,
                                    size, flags);
                } else {
                        if (size < TTE4M)
                                shw_hblkp = sfmmu_shadow_hcreate(sfmmup, vaddr,
                                    size, flags);
                }
        } else if (SFMMU_IS_SHMERID_VALID(rid)) {
                /*
                 * Shared hmes use per region bitmaps in rgn_hmeflag
                 * rather than shadow hmeblks to keep track of the
                 * mapping sizes which have been allocated for the region.
                 * Here we cleanup old invalid hmeblks with this rid,
                 * which may be left around by pageunload().
                 */
                int ttesz;
                caddr_t va;
                caddr_t eva = vaddr + TTEBYTES(size);

                ASSERT(sfmmup != KHATID);

                srdp = sfmmup->sfmmu_srdp;
                ASSERT(srdp != NULL && srdp->srd_refcnt != 0);
                rgnp = srdp->srd_hmergnp[rid];
                ASSERT(rgnp != NULL && rgnp->rgn_id == rid);
                ASSERT(rgnp->rgn_refcnt != 0);
                ASSERT(size <= rgnp->rgn_pgszc);

                ttesz = HBLK_MIN_TTESZ;
                do {
                        if (!(rgnp->rgn_hmeflags & (0x1 << ttesz))) {
                                continue;
                        }

                        if (ttesz > size && ttesz != HBLK_MIN_TTESZ) {
                                sfmmu_cleanup_rhblk(srdp, vaddr, rid, ttesz);
                        } else if (ttesz < size) {
                                for (va = vaddr; va < eva;
                                    va += TTEBYTES(ttesz)) {
                                        sfmmu_cleanup_rhblk(srdp, va, rid,
                                            ttesz);
                                }
                        }
                } while (++ttesz <= rgnp->rgn_pgszc);
        }

fill_hblk:
        owner = (hblk_reserve_thread == curthread) ? 1 : 0;

        if (owner && size == TTE8K) {

                ASSERT(!SFMMU_IS_SHMERID_VALID(rid));
                /*
                 * We are really in a tight spot. We already own
                 * hblk_reserve and we need another hblk.  In anticipation
                 * of this kind of scenario, we specifically set aside
                 * HBLK_RESERVE_MIN number of hblks to be used exclusively
                 * by owner of hblk_reserve.
                 */
                SFMMU_STAT(sf_hblk_recurse_cnt);

                if (!sfmmu_get_free_hblk(&hmeblkp, 1))
                        panic("sfmmu_hblk_alloc: reserve list is empty");

                goto hblk_verify;
        }

        ASSERT(!owner);

        if ((flags & HAT_NO_KALLOC) == 0) {

                sfmmu_cache = ((size == TTE8K) ? sfmmu8_cache : sfmmu1_cache);
                sleep = ((sfmmup == KHATID) ? KM_NOSLEEP : KM_SLEEP);

                if ((hmeblkp = kmem_cache_alloc(sfmmu_cache, sleep)) == NULL) {
                        hmeblkp = sfmmu_hblk_steal(size);
                } else {
                        /*
                         * if we are the owner of hblk_reserve,
                         * swap hblk_reserve with hmeblkp and
                         * start a fresh life.  Hope things go
                         * better this time.
                         */
                        if (hblk_reserve_thread == curthread) {
                                ASSERT(sfmmu_cache == sfmmu8_cache);
                                sfmmu_hblk_swap(hmeblkp);
                                hblk_reserve_thread = NULL;
                                mutex_exit(&hblk_reserve_lock);
                                goto fill_hblk;
                        }
                        /*
                         * let's donate this hblk to our reserve list if
                         * we are not mapping kernel range
                         */
                        if (size == TTE8K && sfmmup != KHATID) {
                                if (sfmmu_put_free_hblk(hmeblkp, 0))
                                        goto fill_hblk;
                        }
                }
        } else {
                /*
                 * We are here to map the slab in sfmmu8_cache; let's
                 * check if we could tap our reserve list; if successful,
                 * this will avoid the pain of going thru sfmmu_hblk_swap
                 */
                SFMMU_STAT(sf_hblk_slab_cnt);
                if (!sfmmu_get_free_hblk(&hmeblkp, 0)) {
                        /*
                         * let's start hblk_reserve dance
                         */
                        SFMMU_STAT(sf_hblk_reserve_cnt);
                        owner = 1;
                        mutex_enter(&hblk_reserve_lock);
                        hmeblkp = HBLK_RESERVE;
                        hblk_reserve_thread = curthread;
                }
        }

hblk_verify:
        ASSERT(hmeblkp != NULL);
        set_hblk_sz(hmeblkp, size);
        ASSERT(hmeblkp->hblk_nextpa == va_to_pa((caddr_t)hmeblkp));
        SFMMU_HASH_LOCK(hmebp);
        HME_HASH_FAST_SEARCH(hmebp, hblktag, newhblkp);
        if (newhblkp != NULL) {
                SFMMU_HASH_UNLOCK(hmebp);
                if (hmeblkp != HBLK_RESERVE) {
                        /*
                         * This is really tricky!
                         *
                         * vmem_alloc(vmem_seg_arena)
                         *  vmem_alloc(vmem_internal_arena)
                         *   segkmem_alloc(heap_arena)
                         *    vmem_alloc(heap_arena)
                         *    page_create()
                         *    hat_memload()
                         *      kmem_cache_free()
                         *       kmem_cache_alloc()
                         *        kmem_slab_create()
                         *         vmem_alloc(kmem_internal_arena)
                         *          segkmem_alloc(heap_arena)
                         *              vmem_alloc(heap_arena)
                         *              page_create()
                         *              hat_memload()
                         *                kmem_cache_free()
                         *              ...
                         *
                         * Thus, hat_memload() could call kmem_cache_free
                         * for enough number of times that we could easily
                         * hit the bottom of the stack or run out of reserve
                         * list of vmem_seg structs.  So, we must donate
                         * this hblk to reserve list if it's allocated
                         * from sfmmu8_cache *and* mapping kernel range.
                         * We don't need to worry about freeing hmeblk1's
                         * to kmem since they don't map any kmem slabs.
                         *
                         * Note: When segkmem supports largepages, we must
                         * free hmeblk1's to reserve list as well.
                         */
                        forcefree = (sfmmup == KHATID) ? 1 : 0;
                        if (size == TTE8K &&
                            sfmmu_put_free_hblk(hmeblkp, forcefree)) {
                                goto re_verify;
                        }
                        ASSERT(sfmmup != KHATID);
                        kmem_cache_free(get_hblk_cache(hmeblkp), hmeblkp);
                } else {
                        /*
                         * Hey! we don't need hblk_reserve any more.
                         */
                        ASSERT(owner);
                        hblk_reserve_thread = NULL;
                        mutex_exit(&hblk_reserve_lock);
                        owner = 0;
                }
re_verify:
                /*
                 * let's check if the goodies are still present
                 */
                SFMMU_HASH_LOCK(hmebp);
                HME_HASH_FAST_SEARCH(hmebp, hblktag, newhblkp);
                if (newhblkp != NULL) {
                        /*
                         * return newhblkp if it's not hblk_reserve;
                         * if newhblkp is hblk_reserve, return it
                         * _only if_ we are the owner of hblk_reserve.
                         */
                        if (newhblkp != HBLK_RESERVE || owner) {
                                ASSERT(!SFMMU_IS_SHMERID_VALID(rid) ||
                                    newhblkp->hblk_shared);
                                ASSERT(SFMMU_IS_SHMERID_VALID(rid) ||
                                    !newhblkp->hblk_shared);
                                return (newhblkp);
                        } else {
                                /*
                                 * we just hit hblk_reserve in the hash and
                                 * we are not the owner of that;
                                 *
                                 * block until hblk_reserve_thread completes
                                 * swapping hblk_reserve and try the dance
                                 * once again.
                                 */
                                SFMMU_HASH_UNLOCK(hmebp);
                                mutex_enter(&hblk_reserve_lock);
                                mutex_exit(&hblk_reserve_lock);
                                SFMMU_STAT(sf_hblk_reserve_hit);
                                goto fill_hblk;
                        }
                } else {
                        /*
                         * it's no more! try the dance once again.
                         */
                        SFMMU_HASH_UNLOCK(hmebp);
                        goto fill_hblk;
                }
        }

hblk_init:
        if (SFMMU_IS_SHMERID_VALID(rid)) {
                uint16_t tteflag = 0x1 <<
                    ((size < HBLK_MIN_TTESZ) ? HBLK_MIN_TTESZ : size);

                if (!(rgnp->rgn_hmeflags & tteflag)) {
                        atomic_or_16(&rgnp->rgn_hmeflags, tteflag);
                }
                hmeblkp->hblk_shared = 1;
        } else {
                hmeblkp->hblk_shared = 0;
        }
        set_hblk_sz(hmeblkp, size);
        ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));
        hmeblkp->hblk_next = (struct hme_blk *)NULL;
        hmeblkp->hblk_tag = hblktag;
        hmeblkp->hblk_shadow = shw_hblkp;
        hblkpa = hmeblkp->hblk_nextpa;
        hmeblkp->hblk_nextpa = HMEBLK_ENDPA;

        ASSERT(get_hblk_ttesz(hmeblkp) == size);
        ASSERT(get_hblk_span(hmeblkp) == HMEBLK_SPAN(size));
        ASSERT(hmeblkp->hblk_hmecnt == 0);
        ASSERT(hmeblkp->hblk_vcnt == 0);
        ASSERT(hmeblkp->hblk_lckcnt == 0);
        ASSERT(hblkpa == va_to_pa((caddr_t)hmeblkp));
        sfmmu_hblk_hash_add(hmebp, hmeblkp, hblkpa);
        return (hmeblkp);
}

/*
 * This function cleans up the hme_blk and returns it to the free list.
 */
/* ARGSUSED */
static void
sfmmu_hblk_free(struct hme_blk **listp)
{
        struct hme_blk *hmeblkp, *next_hmeblkp;
        int             size;
        uint_t          critical;
        uint64_t        hblkpa;

        ASSERT(*listp != NULL);

        hmeblkp = *listp;
        while (hmeblkp != NULL) {
                next_hmeblkp = hmeblkp->hblk_next;
                ASSERT(!hmeblkp->hblk_hmecnt);
                ASSERT(!hmeblkp->hblk_vcnt);
                ASSERT(!hmeblkp->hblk_lckcnt);
                ASSERT(hmeblkp != (struct hme_blk *)hblk_reserve);
                ASSERT(hmeblkp->hblk_shared == 0);
                ASSERT(hmeblkp->hblk_shw_bit == 0);
                ASSERT(hmeblkp->hblk_shadow == NULL);

                hblkpa = va_to_pa((caddr_t)hmeblkp);
                ASSERT(hblkpa != (uint64_t)-1);
                critical = (hblktosfmmu(hmeblkp) == KHATID) ? 1 : 0;

                size = get_hblk_ttesz(hmeblkp);
                hmeblkp->hblk_next = NULL;
                hmeblkp->hblk_nextpa = hblkpa;

                if (hmeblkp->hblk_nuc_bit == 0) {

                        if (size != TTE8K ||
                            !sfmmu_put_free_hblk(hmeblkp, critical))
                                kmem_cache_free(get_hblk_cache(hmeblkp),
                                    hmeblkp);
                }
                hmeblkp = next_hmeblkp;
        }
}

#define BUCKETS_TO_SEARCH_BEFORE_UNLOAD 30
#define SFMMU_HBLK_STEAL_THRESHOLD 5

static uint_t sfmmu_hblk_steal_twice;
static uint_t sfmmu_hblk_steal_count, sfmmu_hblk_steal_unload_count;

/*
 * Steal a hmeblk from user or kernel hme hash lists.
 * For 8K tte grab one from reserve pool (freehblkp) before proceeding to
 * steal and if we fail to steal after SFMMU_HBLK_STEAL_THRESHOLD attempts
 * tap into critical reserve of freehblkp.
 * Note: We remain looping in this routine until we find one.
 */
static struct hme_blk *
sfmmu_hblk_steal(int size)
{
        static struct hmehash_bucket *uhmehash_steal_hand = NULL;
        struct hmehash_bucket *hmebp;
        struct hme_blk *hmeblkp = NULL, *pr_hblk;
        uint64_t hblkpa;
        int i;
        uint_t loop_cnt = 0, critical;

        for (;;) {
                /* Check cpu hblk pending queues */
                if ((hmeblkp = sfmmu_check_pending_hblks(size)) != NULL) {
                        hmeblkp->hblk_nextpa = va_to_pa((caddr_t)hmeblkp);
                        ASSERT(hmeblkp->hblk_hmecnt == 0);
                        ASSERT(hmeblkp->hblk_vcnt == 0);
                        return (hmeblkp);
                }

                if (size == TTE8K) {
                        critical =
                            (++loop_cnt > SFMMU_HBLK_STEAL_THRESHOLD) ? 1 : 0;
                        if (sfmmu_get_free_hblk(&hmeblkp, critical))
                                return (hmeblkp);
                }

                hmebp = (uhmehash_steal_hand == NULL) ? uhme_hash :
                    uhmehash_steal_hand;
                ASSERT(hmebp >= uhme_hash && hmebp <= &uhme_hash[UHMEHASH_SZ]);

                for (i = 0; hmeblkp == NULL && i <= UHMEHASH_SZ +
                    BUCKETS_TO_SEARCH_BEFORE_UNLOAD; i++) {
                        SFMMU_HASH_LOCK(hmebp);
                        hmeblkp = hmebp->hmeblkp;
                        hblkpa = hmebp->hmeh_nextpa;
                        pr_hblk = NULL;
                        while (hmeblkp) {
                                /*
                                 * check if it is a hmeblk that is not locked
                                 * and not shared. skip shadow hmeblks with
                                 * shadow_mask set i.e valid count non zero.
                                 */
                                if ((get_hblk_ttesz(hmeblkp) == size) &&
                                    (hmeblkp->hblk_shw_bit == 0 ||
                                    hmeblkp->hblk_vcnt == 0) &&
                                    (hmeblkp->hblk_lckcnt == 0)) {
                                        /*
                                         * there is a high probability that we
                                         * will find a free one. search some
                                         * buckets for a free hmeblk initially
                                         * before unloading a valid hmeblk.
                                         */
                                        if ((hmeblkp->hblk_vcnt == 0 &&
                                            hmeblkp->hblk_hmecnt == 0) || (i >=
                                            BUCKETS_TO_SEARCH_BEFORE_UNLOAD)) {
                                                if (sfmmu_steal_this_hblk(hmebp,
                                                    hmeblkp, hblkpa, pr_hblk)) {
                                                        /*
                                                         * Hblk is unloaded
                                                         * successfully
                                                         */
                                                        break;
                                                }
                                        }
                                }
                                pr_hblk = hmeblkp;
                                hblkpa = hmeblkp->hblk_nextpa;
                                hmeblkp = hmeblkp->hblk_next;
                        }

                        SFMMU_HASH_UNLOCK(hmebp);
                        if (hmebp++ == &uhme_hash[UHMEHASH_SZ])
                                hmebp = uhme_hash;
                }
                uhmehash_steal_hand = hmebp;

                if (hmeblkp != NULL)
                        break;

                /*
                 * in the worst case, look for a free one in the kernel
                 * hash table.
                 */
                for (i = 0, hmebp = khme_hash; i <= KHMEHASH_SZ; i++) {
                        SFMMU_HASH_LOCK(hmebp);
                        hmeblkp = hmebp->hmeblkp;
                        hblkpa = hmebp->hmeh_nextpa;
                        pr_hblk = NULL;
                        while (hmeblkp) {
                                /*
                                 * check if it is free hmeblk
                                 */
                                if ((get_hblk_ttesz(hmeblkp) == size) &&
                                    (hmeblkp->hblk_lckcnt == 0) &&
                                    (hmeblkp->hblk_vcnt == 0) &&
                                    (hmeblkp->hblk_hmecnt == 0)) {
                                        if (sfmmu_steal_this_hblk(hmebp,
                                            hmeblkp, hblkpa, pr_hblk)) {
                                                break;
                                        } else {
                                                /*
                                                 * Cannot fail since we have
                                                 * hash lock.
                                                 */
                                                panic("fail to steal?");
                                        }
                                }

                                pr_hblk = hmeblkp;
                                hblkpa = hmeblkp->hblk_nextpa;
                                hmeblkp = hmeblkp->hblk_next;
                        }

                        SFMMU_HASH_UNLOCK(hmebp);
                        if (hmebp++ == &khme_hash[KHMEHASH_SZ])
                                hmebp = khme_hash;
                }

                if (hmeblkp != NULL)
                        break;
                sfmmu_hblk_steal_twice++;
        }
        return (hmeblkp);
}

/*
 * This routine does real work to prepare a hblk to be "stolen" by
 * unloading the mappings, updating shadow counts ....
 * It returns 1 if the block is ready to be reused (stolen), or 0
 * means the block cannot be stolen yet- pageunload is still working
 * on this hblk.
 */
static int
sfmmu_steal_this_hblk(struct hmehash_bucket *hmebp, struct hme_blk *hmeblkp,
    uint64_t hblkpa, struct hme_blk *pr_hblk)
{
        int shw_size, vshift;
        struct hme_blk *shw_hblkp;
        caddr_t vaddr;
        uint_t shw_mask, newshw_mask;
        struct hme_blk *list = NULL;

        ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));

        /*
         * check if the hmeblk is free, unload if necessary
         */
        if (hmeblkp->hblk_vcnt || hmeblkp->hblk_hmecnt) {
                sfmmu_t *sfmmup;
                demap_range_t dmr;

                sfmmup = hblktosfmmu(hmeblkp);
                if (hmeblkp->hblk_shared || sfmmup->sfmmu_ismhat) {
                        return (0);
                }
                DEMAP_RANGE_INIT(sfmmup, &dmr);
                (void) sfmmu_hblk_unload(sfmmup, hmeblkp,
                    (caddr_t)get_hblk_base(hmeblkp),
                    get_hblk_endaddr(hmeblkp), &dmr, HAT_UNLOAD);
                DEMAP_RANGE_FLUSH(&dmr);
                if (hmeblkp->hblk_vcnt || hmeblkp->hblk_hmecnt) {
                        /*
                         * Pageunload is working on the same hblk.
                         */
                        return (0);
                }

                sfmmu_hblk_steal_unload_count++;
        }

        ASSERT(hmeblkp->hblk_lckcnt == 0);
        ASSERT(hmeblkp->hblk_vcnt == 0 && hmeblkp->hblk_hmecnt == 0);

        sfmmu_hblk_hash_rm(hmebp, hmeblkp, pr_hblk, &list, 1);
        hmeblkp->hblk_nextpa = hblkpa;

        shw_hblkp = hmeblkp->hblk_shadow;
        if (shw_hblkp) {
                ASSERT(!hmeblkp->hblk_shared);
                shw_size = get_hblk_ttesz(shw_hblkp);
                vaddr = (caddr_t)get_hblk_base(hmeblkp);
                vshift = vaddr_to_vshift(shw_hblkp->hblk_tag, vaddr, shw_size);
                ASSERT(vshift < 8);
                /*
                 * Atomically clear shadow mask bit
                 */
                do {
                        shw_mask = shw_hblkp->hblk_shw_mask;
                        ASSERT(shw_mask & (1 << vshift));
                        newshw_mask = shw_mask & ~(1 << vshift);
                        newshw_mask = atomic_cas_32(&shw_hblkp->hblk_shw_mask,
                            shw_mask, newshw_mask);
                } while (newshw_mask != shw_mask);
                hmeblkp->hblk_shadow = NULL;
        }

        /*
         * remove shadow bit if we are stealing an unused shadow hmeblk.
         * sfmmu_hblk_alloc needs it that way, will set shadow bit later if
         * we are indeed allocating a shadow hmeblk.
         */
        hmeblkp->hblk_shw_bit = 0;

        if (hmeblkp->hblk_shared) {
                sf_srd_t        *srdp;
                sf_region_t     *rgnp;
                uint_t          rid;

                srdp = hblktosrd(hmeblkp);
                ASSERT(srdp != NULL && srdp->srd_refcnt != 0);
                rid = hmeblkp->hblk_tag.htag_rid;
                ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                rgnp = srdp->srd_hmergnp[rid];
                ASSERT(rgnp != NULL);
                SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp, rgnp, rid);
                hmeblkp->hblk_shared = 0;
        }

        sfmmu_hblk_steal_count++;
        SFMMU_STAT(sf_steal_count);

        return (1);
}

struct hme_blk *
sfmmu_hmetohblk(struct sf_hment *sfhme)
{
        struct hme_blk *hmeblkp;
        struct sf_hment *sfhme0;
        struct hme_blk *hblk_dummy = 0;

        /*
         * No dummy sf_hments, please.
         */
        ASSERT(sfhme->hme_tte.ll != 0);

        sfhme0 = sfhme - sfhme->hme_tte.tte_hmenum;
        hmeblkp = (struct hme_blk *)((uintptr_t)sfhme0 -
            (uintptr_t)&hblk_dummy->hblk_hme[0]);

        return (hmeblkp);
}

/*
 * On swapin, get appropriately sized TSB(s) and clear the HAT_SWAPPED flag.
 * If we can't get appropriately sized TSB(s), try for 8K TSB(s) using
 * KM_SLEEP allocation.
 *
 * Return 0 on success, -1 otherwise.
 */
static void
sfmmu_tsb_swapin(sfmmu_t *sfmmup, hatlock_t *hatlockp)
{
        struct tsb_info *tsbinfop, *next;
        tsb_replace_rc_t rc;
        boolean_t gotfirst = B_FALSE;

        ASSERT(sfmmup != ksfmmup);
        ASSERT(sfmmu_hat_lock_held(sfmmup));

        while (SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPIN)) {
                cv_wait(&sfmmup->sfmmu_tsb_cv, HATLOCK_MUTEXP(hatlockp));
        }

        if (SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPPED)) {
                SFMMU_FLAGS_SET(sfmmup, HAT_SWAPIN);
        } else {
                return;
        }

        ASSERT(sfmmup->sfmmu_tsb != NULL);

        /*
         * Loop over all tsbinfo's replacing them with ones that actually have
         * a TSB.  If any of the replacements ever fail, bail out of the loop.
         */
        for (tsbinfop = sfmmup->sfmmu_tsb; tsbinfop != NULL; tsbinfop = next) {
                ASSERT(tsbinfop->tsb_flags & TSB_SWAPPED);
                next = tsbinfop->tsb_next;
                rc = sfmmu_replace_tsb(sfmmup, tsbinfop, tsbinfop->tsb_szc,
                    hatlockp, TSB_SWAPIN);
                if (rc != TSB_SUCCESS) {
                        break;
                }
                gotfirst = B_TRUE;
        }

        switch (rc) {
        case TSB_SUCCESS:
                SFMMU_FLAGS_CLEAR(sfmmup, HAT_SWAPPED|HAT_SWAPIN);
                cv_broadcast(&sfmmup->sfmmu_tsb_cv);
                return;
        case TSB_LOSTRACE:
                break;
        case TSB_ALLOCFAIL:
                break;
        default:
                panic("sfmmu_replace_tsb returned unrecognized failure code "
                    "%d", rc);
        }

        /*
         * In this case, we failed to get one of our TSBs.  If we failed to
         * get the first TSB, get one of minimum size (8KB).  Walk the list
         * and throw away the tsbinfos, starting where the allocation failed;
         * we can get by with just one TSB as long as we don't leave the
         * SWAPPED tsbinfo structures lying around.
         */
        tsbinfop = sfmmup->sfmmu_tsb;
        next = tsbinfop->tsb_next;
        tsbinfop->tsb_next = NULL;

        sfmmu_hat_exit(hatlockp);
        for (tsbinfop = next; tsbinfop != NULL; tsbinfop = next) {
                next = tsbinfop->tsb_next;
                sfmmu_tsbinfo_free(tsbinfop);
        }
        hatlockp = sfmmu_hat_enter(sfmmup);

        /*
         * If we don't have any TSBs, get a single 8K TSB for 8K, 64K and 512K
         * pages.
         */
        if (!gotfirst) {
                tsbinfop = sfmmup->sfmmu_tsb;
                rc = sfmmu_replace_tsb(sfmmup, tsbinfop, TSB_MIN_SZCODE,
                    hatlockp, TSB_SWAPIN | TSB_FORCEALLOC);
                ASSERT(rc == TSB_SUCCESS);
        }

        SFMMU_FLAGS_CLEAR(sfmmup, HAT_SWAPPED|HAT_SWAPIN);
        cv_broadcast(&sfmmup->sfmmu_tsb_cv);
}

static int
sfmmu_is_rgnva(sf_srd_t *srdp, caddr_t addr, ulong_t w, ulong_t bmw)
{
        ulong_t bix = 0;
        uint_t rid;
        sf_region_t *rgnp;

        ASSERT(srdp != NULL);
        ASSERT(srdp->srd_refcnt != 0);

        w <<= BT_ULSHIFT;
        while (bmw) {
                if (!(bmw & 0x1)) {
                        bix++;
                        bmw >>= 1;
                        continue;
                }
                rid = w | bix;
                rgnp = srdp->srd_hmergnp[rid];
                ASSERT(rgnp->rgn_refcnt > 0);
                ASSERT(rgnp->rgn_id == rid);
                if (addr < rgnp->rgn_saddr ||
                    addr >= (rgnp->rgn_saddr + rgnp->rgn_size)) {
                        bix++;
                        bmw >>= 1;
                } else {
                        return (1);
                }
        }
        return (0);
}

/*
 * Handle exceptions for low level tsb_handler.
 *
 * There are many scenarios that could land us here:
 *
 * If the context is invalid we land here. The context can be invalid
 * for 3 reasons: 1) we couldn't allocate a new context and now need to
 * perform a wrap around operation in order to allocate a new context.
 * 2) Context was invalidated to change pagesize programming 3) ISMs or
 * TSBs configuration is changeing for this process and we are forced into
 * here to do a syncronization operation. If the context is valid we can
 * be here from window trap hanlder. In this case just call trap to handle
 * the fault.
 *
 * Note that the process will run in INVALID_CONTEXT before
 * faulting into here and subsequently loading the MMU registers
 * (including the TSB base register) associated with this process.
 * For this reason, the trap handlers must all test for
 * INVALID_CONTEXT before attempting to access any registers other
 * than the context registers.
 */
void
sfmmu_tsbmiss_exception(struct regs *rp, uintptr_t tagaccess, uint_t traptype)
{
        sfmmu_t *sfmmup, *shsfmmup;
        uint_t ctxtype;
        klwp_id_t lwp;
        char lwp_save_state;
        hatlock_t *hatlockp, *shatlockp;
        struct tsb_info *tsbinfop;
        struct tsbmiss *tsbmp;
        sf_scd_t *scdp;

        SFMMU_STAT(sf_tsb_exceptions);
        SFMMU_MMU_STAT(mmu_tsb_exceptions);
        sfmmup = astosfmmu(curthread->t_procp->p_as);
        /*
         * note that in sun4u, tagacces register contains ctxnum
         * while sun4v passes ctxtype in the tagaccess register.
         */
        ctxtype = tagaccess & TAGACC_CTX_MASK;

        ASSERT(sfmmup != ksfmmup && ctxtype != KCONTEXT);
        ASSERT(sfmmup->sfmmu_ismhat == 0);
        ASSERT(!SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPPED) ||
            ctxtype == INVALID_CONTEXT);

        if (ctxtype != INVALID_CONTEXT && traptype != T_DATA_PROT) {
                /*
                 * We may land here because shme bitmap and pagesize
                 * flags are updated lazily in tsbmiss area on other cpus.
                 * If we detect here that tsbmiss area is out of sync with
                 * sfmmu update it and retry the trapped instruction.
                 * Otherwise call trap().
                 */
                int ret = 0;
                uchar_t tteflag_mask = (1 << TTE64K) | (1 << TTE8K);
                caddr_t addr = (caddr_t)(tagaccess & TAGACC_VADDR_MASK);

                /*
                 * Must set lwp state to LWP_SYS before
                 * trying to acquire any adaptive lock
                 */
                lwp = ttolwp(curthread);
                ASSERT(lwp);
                lwp_save_state = lwp->lwp_state;
                lwp->lwp_state = LWP_SYS;

                hatlockp = sfmmu_hat_enter(sfmmup);
                kpreempt_disable();
                tsbmp = &tsbmiss_area[CPU->cpu_id];
                ASSERT(sfmmup == tsbmp->usfmmup);
                if (((tsbmp->uhat_tteflags ^ sfmmup->sfmmu_tteflags) &
                    ~tteflag_mask) ||
                    ((tsbmp->uhat_rtteflags ^  sfmmup->sfmmu_rtteflags) &
                    ~tteflag_mask)) {
                        tsbmp->uhat_tteflags = sfmmup->sfmmu_tteflags;
                        tsbmp->uhat_rtteflags = sfmmup->sfmmu_rtteflags;
                        ret = 1;
                }
                if (sfmmup->sfmmu_srdp != NULL) {
                        ulong_t *sm = sfmmup->sfmmu_hmeregion_map.bitmap;
                        ulong_t *tm = tsbmp->shmermap;
                        ulong_t i;
                        for (i = 0; i < SFMMU_HMERGNMAP_WORDS; i++) {
                                ulong_t d = tm[i] ^ sm[i];
                                if (d) {
                                        if (d & sm[i]) {
                                                if (!ret && sfmmu_is_rgnva(
                                                    sfmmup->sfmmu_srdp,
                                                    addr, i, d & sm[i])) {
                                                        ret = 1;
                                                }
                                        }
                                        tm[i] = sm[i];
                                }
                        }
                }
                kpreempt_enable();
                sfmmu_hat_exit(hatlockp);
                lwp->lwp_state = lwp_save_state;
                if (ret) {
                        return;
                }
        } else if (ctxtype == INVALID_CONTEXT) {
                /*
                 * First, make sure we come out of here with a valid ctx,
                 * since if we don't get one we'll simply loop on the
                 * faulting instruction.
                 *
                 * If the ISM mappings are changing, the TSB is relocated,
                 * the process is swapped, the process is joining SCD or
                 * leaving SCD or shared regions we serialize behind the
                 * controlling thread with hat lock, sfmmu_flags and
                 * sfmmu_tsb_cv condition variable.
                 */

                /*
                 * Must set lwp state to LWP_SYS before
                 * trying to acquire any adaptive lock
                 */
                lwp = ttolwp(curthread);
                ASSERT(lwp);
                lwp_save_state = lwp->lwp_state;
                lwp->lwp_state = LWP_SYS;

                hatlockp = sfmmu_hat_enter(sfmmup);
retry:
                if ((scdp = sfmmup->sfmmu_scdp) != NULL) {
                        shsfmmup = scdp->scd_sfmmup;
                        ASSERT(shsfmmup != NULL);

                        for (tsbinfop = shsfmmup->sfmmu_tsb; tsbinfop != NULL;
                            tsbinfop = tsbinfop->tsb_next) {
                                if (tsbinfop->tsb_flags & TSB_RELOC_FLAG) {
                                        /* drop the private hat lock */
                                        sfmmu_hat_exit(hatlockp);
                                        /* acquire the shared hat lock */
                                        shatlockp = sfmmu_hat_enter(shsfmmup);
                                        /*
                                         * recheck to see if anything changed
                                         * after we drop the private hat lock.
                                         */
                                        if (sfmmup->sfmmu_scdp == scdp &&
                                            shsfmmup == scdp->scd_sfmmup) {
                                                sfmmu_tsb_chk_reloc(shsfmmup,
                                                    shatlockp);
                                        }
                                        sfmmu_hat_exit(shatlockp);
                                        hatlockp = sfmmu_hat_enter(sfmmup);
                                        goto retry;
                                }
                        }
                }

                for (tsbinfop = sfmmup->sfmmu_tsb; tsbinfop != NULL;
                    tsbinfop = tsbinfop->tsb_next) {
                        if (tsbinfop->tsb_flags & TSB_RELOC_FLAG) {
                                cv_wait(&sfmmup->sfmmu_tsb_cv,
                                    HATLOCK_MUTEXP(hatlockp));
                                goto retry;
                        }
                }

                /*
                 * Wait for ISM maps to be updated.
                 */
                if (SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY)) {
                        cv_wait(&sfmmup->sfmmu_tsb_cv,
                            HATLOCK_MUTEXP(hatlockp));
                        goto retry;
                }

                /* Is this process joining an SCD? */
                if (SFMMU_FLAGS_ISSET(sfmmup, HAT_JOIN_SCD)) {
                        /*
                         * Flush private TSB and setup shared TSB.
                         * sfmmu_finish_join_scd() does not drop the
                         * hat lock.
                         */
                        sfmmu_finish_join_scd(sfmmup);
                        SFMMU_FLAGS_CLEAR(sfmmup, HAT_JOIN_SCD);
                }

                /*
                 * If we're swapping in, get TSB(s).  Note that we must do
                 * this before we get a ctx or load the MMU state.  Once
                 * we swap in we have to recheck to make sure the TSB(s) and
                 * ISM mappings didn't change while we slept.
                 */
                if (SFMMU_FLAGS_ISSET(sfmmup, HAT_SWAPPED)) {
                        sfmmu_tsb_swapin(sfmmup, hatlockp);
                        goto retry;
                }

                sfmmu_get_ctx(sfmmup);

                sfmmu_hat_exit(hatlockp);
                /*
                 * Must restore lwp_state if not calling
                 * trap() for further processing. Restore
                 * it anyway.
                 */
                lwp->lwp_state = lwp_save_state;
                return;
        }
        trap(rp, (caddr_t)tagaccess, traptype, 0);
}

static void
sfmmu_tsb_chk_reloc(sfmmu_t *sfmmup, hatlock_t *hatlockp)
{
        struct tsb_info *tp;

        ASSERT(sfmmu_hat_lock_held(sfmmup));

        for (tp = sfmmup->sfmmu_tsb; tp != NULL; tp = tp->tsb_next) {
                if (tp->tsb_flags & TSB_RELOC_FLAG) {
                        cv_wait(&sfmmup->sfmmu_tsb_cv,
                            HATLOCK_MUTEXP(hatlockp));
                        break;
                }
        }
}

/*
 * sfmmu_vatopfn_suspended is called from GET_TTE when TL=0 and
 * TTE_SUSPENDED bit set in tte we block on aquiring a page lock
 * rather than spinning to avoid send mondo timeouts with
 * interrupts enabled. When the lock is acquired it is immediately
 * released and we return back to sfmmu_vatopfn just after
 * the GET_TTE call.
 */
void
sfmmu_vatopfn_suspended(caddr_t vaddr, sfmmu_t *sfmmu, tte_t *ttep)
{
        struct page     **pp;

        (void) as_pagelock(sfmmu->sfmmu_as, &pp, vaddr, TTE_CSZ(ttep), S_WRITE);
        as_pageunlock(sfmmu->sfmmu_as, pp, vaddr, TTE_CSZ(ttep), S_WRITE);
}

/*
 * sfmmu_tsbmiss_suspended is called from GET_TTE when TL>0 and
 * TTE_SUSPENDED bit set in tte. We do this so that we can handle
 * cross traps which cannot be handled while spinning in the
 * trap handlers. Simply enter and exit the kpr_suspendlock spin
 * mutex, which is held by the holder of the suspend bit, and then
 * retry the trapped instruction after unwinding.
 */
/*ARGSUSED*/
void
sfmmu_tsbmiss_suspended(struct regs *rp, uintptr_t tagacc, uint_t traptype)
{
        ASSERT(curthread != kreloc_thread);
        mutex_enter(&kpr_suspendlock);
        mutex_exit(&kpr_suspendlock);
}

/*
 * This routine could be optimized to reduce the number of xcalls by flushing
 * the entire TLBs if region reference count is above some threshold but the
 * tradeoff will depend on the size of the TLB. So for now flush the specific
 * page a context at a time.
 *
 * If uselocks is 0 then it's called after all cpus were captured and all the
 * hat locks were taken. In this case don't take the region lock by relying on
 * the order of list region update operations in hat_join_region(),
 * hat_leave_region() and hat_dup_region(). The ordering in those routines
 * guarantees that list is always forward walkable and reaches active sfmmus
 * regardless of where xc_attention() captures a cpu.
 */
cpuset_t
sfmmu_rgntlb_demap(caddr_t addr, sf_region_t *rgnp,
    struct hme_blk *hmeblkp, int uselocks)
{
        sfmmu_t *sfmmup;
        cpuset_t cpuset;
        cpuset_t rcpuset;
        hatlock_t *hatlockp;
        uint_t rid = rgnp->rgn_id;
        sf_rgn_link_t *rlink;
        sf_scd_t *scdp;

        ASSERT(hmeblkp->hblk_shared);
        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
        ASSERT(rid < SFMMU_MAX_HME_REGIONS);

        CPUSET_ZERO(rcpuset);
        if (uselocks) {
                mutex_enter(&rgnp->rgn_mutex);
        }
        sfmmup = rgnp->rgn_sfmmu_head;
        while (sfmmup != NULL) {
                if (uselocks) {
                        hatlockp = sfmmu_hat_enter(sfmmup);
                }

                /*
                 * When an SCD is created the SCD hat is linked on the sfmmu
                 * region lists for each hme region which is part of the
                 * SCD. If we find an SCD hat, when walking these lists,
                 * then we flush the shared TSBs, if we find a private hat,
                 * which is part of an SCD, but where the region
                 * is not part of the SCD then we flush the private TSBs.
                 */
                if (!sfmmup->sfmmu_scdhat && sfmmup->sfmmu_scdp != NULL &&
                    !SFMMU_FLAGS_ISSET(sfmmup, HAT_JOIN_SCD)) {
                        scdp = sfmmup->sfmmu_scdp;
                        if (SF_RGNMAP_TEST(scdp->scd_hmeregion_map, rid)) {
                                if (uselocks) {
                                        sfmmu_hat_exit(hatlockp);
                                }
                                goto next;
                        }
                }

                SFMMU_UNLOAD_TSB(addr, sfmmup, hmeblkp, 0);

                kpreempt_disable();
                cpuset = sfmmup->sfmmu_cpusran;
                CPUSET_AND(cpuset, cpu_ready_set);
                CPUSET_DEL(cpuset, CPU->cpu_id);
                SFMMU_XCALL_STATS(sfmmup);
                xt_some(cpuset, vtag_flushpage_tl1,
                    (uint64_t)addr, (uint64_t)sfmmup);
                vtag_flushpage(addr, (uint64_t)sfmmup);
                if (uselocks) {
                        sfmmu_hat_exit(hatlockp);
                }
                kpreempt_enable();
                CPUSET_OR(rcpuset, cpuset);

next:
                /* LINTED: constant in conditional context */
                SFMMU_HMERID2RLINKP(sfmmup, rid, rlink, 0, 0);
                ASSERT(rlink != NULL);
                sfmmup = rlink->next;
        }
        if (uselocks) {
                mutex_exit(&rgnp->rgn_mutex);
        }
        return (rcpuset);
}

/*
 * This routine takes an sfmmu pointer and the va for an adddress in an
 * ISM region as input and returns the corresponding region id in ism_rid.
 * The return value of 1 indicates that a region has been found and ism_rid
 * is valid, otherwise 0 is returned.
 */
static int
find_ism_rid(sfmmu_t *sfmmup, sfmmu_t *ism_sfmmup, caddr_t va, uint_t *ism_rid)
{
        ism_blk_t       *ism_blkp;
        int             i;
        ism_map_t       *ism_map;
#ifdef DEBUG
        struct hat      *ism_hatid;
#endif
        ASSERT(sfmmu_hat_lock_held(sfmmup));

        ism_blkp = sfmmup->sfmmu_iblk;
        while (ism_blkp != NULL) {
                ism_map = ism_blkp->iblk_maps;
                for (i = 0; i < ISM_MAP_SLOTS && ism_map[i].imap_ismhat; i++) {
                        if ((va >= ism_start(ism_map[i])) &&
                            (va < ism_end(ism_map[i]))) {

                                *ism_rid = ism_map[i].imap_rid;
#ifdef DEBUG
                                ism_hatid = ism_map[i].imap_ismhat;
                                ASSERT(ism_hatid == ism_sfmmup);
                                ASSERT(ism_hatid->sfmmu_ismhat);
#endif
                                return (1);
                        }
                }
                ism_blkp = ism_blkp->iblk_next;
        }
        return (0);
}

/*
 * Special routine to flush out ism mappings- TSBs, TLBs and D-caches.
 * This routine may be called with all cpu's captured. Therefore, the
 * caller is responsible for holding all locks and disabling kernel
 * preemption.
 */
/* ARGSUSED */
static void
sfmmu_ismtlbcache_demap(caddr_t addr, sfmmu_t *ism_sfmmup,
    struct hme_blk *hmeblkp, pfn_t pfnum, int cache_flush_flag)
{
        cpuset_t        cpuset;
        caddr_t         va;
        ism_ment_t      *ment;
        sfmmu_t         *sfmmup;
#ifdef VAC
        int             vcolor;
#endif

        sf_scd_t        *scdp;
        uint_t          ism_rid;

        ASSERT(!hmeblkp->hblk_shared);
        /*
         * Walk the ism_hat's mapping list and flush the page
         * from every hat sharing this ism_hat. This routine
         * may be called while all cpu's have been captured.
         * Therefore we can't attempt to grab any locks. For now
         * this means we will protect the ism mapping list under
         * a single lock which will be grabbed by the caller.
         * If hat_share/unshare scalibility becomes a performance
         * problem then we may need to re-think ism mapping list locking.
         */
        ASSERT(ism_sfmmup->sfmmu_ismhat);
        ASSERT(MUTEX_HELD(&ism_mlist_lock));
        addr = (caddr_t)((uintptr_t)addr - (uintptr_t)ISMID_STARTADDR);

        for (ment = ism_sfmmup->sfmmu_iment; ment; ment = ment->iment_next) {

                sfmmup = ment->iment_hat;

                va = ment->iment_base_va;
                va = (caddr_t)((uintptr_t)va  + (uintptr_t)addr);

                /*
                 * When an SCD is created the SCD hat is linked on the ism
                 * mapping lists for each ISM segment which is part of the
                 * SCD. If we find an SCD hat, when walking these lists,
                 * then we flush the shared TSBs, if we find a private hat,
                 * which is part of an SCD, but where the region
                 * corresponding to this va is not part of the SCD then we
                 * flush the private TSBs.
                 */
                if (!sfmmup->sfmmu_scdhat && sfmmup->sfmmu_scdp != NULL &&
                    !SFMMU_FLAGS_ISSET(sfmmup, HAT_JOIN_SCD) &&
                    !SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY)) {
                        if (!find_ism_rid(sfmmup, ism_sfmmup, va,
                            &ism_rid)) {
                                cmn_err(CE_PANIC,
                                    "can't find matching ISM rid!");
                        }

                        scdp = sfmmup->sfmmu_scdp;
                        if (SFMMU_IS_ISMRID_VALID(ism_rid) &&
                            SF_RGNMAP_TEST(scdp->scd_ismregion_map,
                            ism_rid)) {
                                continue;
                        }
                }
                SFMMU_UNLOAD_TSB(va, sfmmup, hmeblkp, 1);

                cpuset = sfmmup->sfmmu_cpusran;
                CPUSET_AND(cpuset, cpu_ready_set);
                CPUSET_DEL(cpuset, CPU->cpu_id);
                SFMMU_XCALL_STATS(sfmmup);
                xt_some(cpuset, vtag_flushpage_tl1, (uint64_t)va,
                    (uint64_t)sfmmup);
                vtag_flushpage(va, (uint64_t)sfmmup);

#ifdef VAC
                /*
                 * Flush D$
                 * When flushing D$ we must flush all
                 * cpu's. See sfmmu_cache_flush().
                 */
                if (cache_flush_flag == CACHE_FLUSH) {
                        cpuset = cpu_ready_set;
                        CPUSET_DEL(cpuset, CPU->cpu_id);

                        SFMMU_XCALL_STATS(sfmmup);
                        vcolor = addr_to_vcolor(va);
                        xt_some(cpuset, vac_flushpage_tl1, pfnum, vcolor);
                        vac_flushpage(pfnum, vcolor);
                }
#endif  /* VAC */
        }
}

/*
 * Demaps the TSB, CPU caches, and flushes all TLBs on all CPUs of
 * a particular virtual address and ctx.  If noflush is set we do not
 * flush the TLB/TSB.  This function may or may not be called with the
 * HAT lock held.
 */
static void
sfmmu_tlbcache_demap(caddr_t addr, sfmmu_t *sfmmup, struct hme_blk *hmeblkp,
    pfn_t pfnum, int tlb_noflush, int cpu_flag, int cache_flush_flag,
    int hat_lock_held)
{
#ifdef VAC
        int vcolor;
#endif
        cpuset_t cpuset;
        hatlock_t *hatlockp;

        ASSERT(!hmeblkp->hblk_shared);

#if defined(lint) && !defined(VAC)
        pfnum = pfnum;
        cpu_flag = cpu_flag;
        cache_flush_flag = cache_flush_flag;
#endif

        /*
         * There is no longer a need to protect against ctx being
         * stolen here since we don't store the ctx in the TSB anymore.
         */
#ifdef VAC
        vcolor = addr_to_vcolor(addr);
#endif

        /*
         * We must hold the hat lock during the flush of TLB,
         * to avoid a race with sfmmu_invalidate_ctx(), where
         * sfmmu_cnum on a MMU could be set to INVALID_CONTEXT,
         * causing TLB demap routine to skip flush on that MMU.
         * If the context on a MMU has already been set to
         * INVALID_CONTEXT, we just get an extra flush on
         * that MMU.
         */
        if (!hat_lock_held && !tlb_noflush)
                hatlockp = sfmmu_hat_enter(sfmmup);

        kpreempt_disable();
        if (!tlb_noflush) {
                /*
                 * Flush the TSB and TLB.
                 */
                SFMMU_UNLOAD_TSB(addr, sfmmup, hmeblkp, 0);

                cpuset = sfmmup->sfmmu_cpusran;
                CPUSET_AND(cpuset, cpu_ready_set);
                CPUSET_DEL(cpuset, CPU->cpu_id);

                SFMMU_XCALL_STATS(sfmmup);

                xt_some(cpuset, vtag_flushpage_tl1, (uint64_t)addr,
                    (uint64_t)sfmmup);

                vtag_flushpage(addr, (uint64_t)sfmmup);
        }

        if (!hat_lock_held && !tlb_noflush)
                sfmmu_hat_exit(hatlockp);

#ifdef VAC
        /*
         * Flush the D$
         *
         * Even if the ctx is stolen, we need to flush the
         * cache. Our ctx stealer only flushes the TLBs.
         */
        if (cache_flush_flag == CACHE_FLUSH) {
                if (cpu_flag & FLUSH_ALL_CPUS) {
                        cpuset = cpu_ready_set;
                } else {
                        cpuset = sfmmup->sfmmu_cpusran;
                        CPUSET_AND(cpuset, cpu_ready_set);
                }
                CPUSET_DEL(cpuset, CPU->cpu_id);
                SFMMU_XCALL_STATS(sfmmup);
                xt_some(cpuset, vac_flushpage_tl1, pfnum, vcolor);
                vac_flushpage(pfnum, vcolor);
        }
#endif  /* VAC */
        kpreempt_enable();
}

/*
 * Demaps the TSB and flushes all TLBs on all cpus for a particular virtual
 * address and ctx.  If noflush is set we do not currently do anything.
 * This function may or may not be called with the HAT lock held.
 */
static void
sfmmu_tlb_demap(caddr_t addr, sfmmu_t *sfmmup, struct hme_blk *hmeblkp,
    int tlb_noflush, int hat_lock_held)
{
        cpuset_t cpuset;
        hatlock_t *hatlockp;

        ASSERT(!hmeblkp->hblk_shared);

        /*
         * If the process is exiting we have nothing to do.
         */
        if (tlb_noflush)
                return;

        /*
         * Flush TSB.
         */
        if (!hat_lock_held)
                hatlockp = sfmmu_hat_enter(sfmmup);
        SFMMU_UNLOAD_TSB(addr, sfmmup, hmeblkp, 0);

        kpreempt_disable();

        cpuset = sfmmup->sfmmu_cpusran;
        CPUSET_AND(cpuset, cpu_ready_set);
        CPUSET_DEL(cpuset, CPU->cpu_id);

        SFMMU_XCALL_STATS(sfmmup);
        xt_some(cpuset, vtag_flushpage_tl1, (uint64_t)addr, (uint64_t)sfmmup);

        vtag_flushpage(addr, (uint64_t)sfmmup);

        if (!hat_lock_held)
                sfmmu_hat_exit(hatlockp);

        kpreempt_enable();

}

/*
 * Special case of sfmmu_tlb_demap for MMU_PAGESIZE hblks. Use the xcall
 * call handler that can flush a range of pages to save on xcalls.
 */
static int sfmmu_xcall_save;

/*
 * this routine is never used for demaping addresses backed by SRD hmeblks.
 */
static void
sfmmu_tlb_range_demap(demap_range_t *dmrp)
{
        sfmmu_t *sfmmup = dmrp->dmr_sfmmup;
        hatlock_t *hatlockp;
        cpuset_t cpuset;
        uint64_t sfmmu_pgcnt;
        pgcnt_t pgcnt = 0;
        int pgunload = 0;
        int dirtypg = 0;
        caddr_t addr = dmrp->dmr_addr;
        caddr_t eaddr;
        uint64_t bitvec = dmrp->dmr_bitvec;

        ASSERT(bitvec & 1);

        /*
         * Flush TSB and calculate number of pages to flush.
         */
        while (bitvec != 0) {
                dirtypg = 0;
                /*
                 * Find the first page to flush and then count how many
                 * pages there are after it that also need to be flushed.
                 * This way the number of TSB flushes is minimized.
                 */
                while ((bitvec & 1) == 0) {
                        pgcnt++;
                        addr += MMU_PAGESIZE;
                        bitvec >>= 1;
                }
                while (bitvec & 1) {
                        dirtypg++;
                        bitvec >>= 1;
                }
                eaddr = addr + ptob(dirtypg);
                hatlockp = sfmmu_hat_enter(sfmmup);
                sfmmu_unload_tsb_range(sfmmup, addr, eaddr, TTE8K);
                sfmmu_hat_exit(hatlockp);
                pgunload += dirtypg;
                addr = eaddr;
                pgcnt += dirtypg;
        }

        ASSERT((pgcnt<<MMU_PAGESHIFT) <= dmrp->dmr_endaddr - dmrp->dmr_addr);
        if (sfmmup->sfmmu_free == 0) {
                addr = dmrp->dmr_addr;
                bitvec = dmrp->dmr_bitvec;

                /*
                 * make sure it has SFMMU_PGCNT_SHIFT bits only,
                 * as it will be used to pack argument for xt_some
                 */
                ASSERT((pgcnt > 0) &&
                    (pgcnt <= (1 << SFMMU_PGCNT_SHIFT)));

                /*
                 * Encode pgcnt as (pgcnt -1 ), and pass (pgcnt - 1) in
                 * the low 6 bits of sfmmup. This is doable since pgcnt
                 * always >= 1.
                 */
                ASSERT(!((uint64_t)sfmmup & SFMMU_PGCNT_MASK));
                sfmmu_pgcnt = (uint64_t)sfmmup |
                    ((pgcnt - 1) & SFMMU_PGCNT_MASK);

                /*
                 * We must hold the hat lock during the flush of TLB,
                 * to avoid a race with sfmmu_invalidate_ctx(), where
                 * sfmmu_cnum on a MMU could be set to INVALID_CONTEXT,
                 * causing TLB demap routine to skip flush on that MMU.
                 * If the context on a MMU has already been set to
                 * INVALID_CONTEXT, we just get an extra flush on
                 * that MMU.
                 */
                hatlockp = sfmmu_hat_enter(sfmmup);
                kpreempt_disable();

                cpuset = sfmmup->sfmmu_cpusran;
                CPUSET_AND(cpuset, cpu_ready_set);
                CPUSET_DEL(cpuset, CPU->cpu_id);

                SFMMU_XCALL_STATS(sfmmup);
                xt_some(cpuset, vtag_flush_pgcnt_tl1, (uint64_t)addr,
                    sfmmu_pgcnt);

                for (; bitvec != 0; bitvec >>= 1) {
                        if (bitvec & 1)
                                vtag_flushpage(addr, (uint64_t)sfmmup);
                        addr += MMU_PAGESIZE;
                }
                kpreempt_enable();
                sfmmu_hat_exit(hatlockp);

                sfmmu_xcall_save += (pgunload-1);
        }
        dmrp->dmr_bitvec = 0;
}

/*
 * In cases where we need to synchronize with TLB/TSB miss trap
 * handlers, _and_ need to flush the TLB, it's a lot easier to
 * throw away the context from the process than to do a
 * special song and dance to keep things consistent for the
 * handlers.
 *
 * Since the process suddenly ends up without a context and our caller
 * holds the hat lock, threads that fault after this function is called
 * will pile up on the lock.  We can then do whatever we need to
 * atomically from the context of the caller.  The first blocked thread
 * to resume executing will get the process a new context, and the
 * process will resume executing.
 *
 * One added advantage of this approach is that on MMUs that
 * support a "flush all" operation, we will delay the flush until
 * cnum wrap-around, and then flush the TLB one time.  This
 * is rather rare, so it's a lot less expensive than making 8000
 * x-calls to flush the TLB 8000 times.
 *
 * A per-process (PP) lock is used to synchronize ctx allocations in
 * resume() and ctx invalidations here.
 */
static void
sfmmu_invalidate_ctx(sfmmu_t *sfmmup)
{
        cpuset_t cpuset;
        int cnum, currcnum;
        mmu_ctx_t *mmu_ctxp;
        int i;
        uint_t pstate_save;

        SFMMU_STAT(sf_ctx_inv);

        ASSERT(sfmmu_hat_lock_held(sfmmup));
        ASSERT(sfmmup != ksfmmup);

        kpreempt_disable();

        mmu_ctxp = CPU_MMU_CTXP(CPU);
        ASSERT(mmu_ctxp);
        ASSERT(mmu_ctxp->mmu_idx < max_mmu_ctxdoms);
        ASSERT(mmu_ctxp == mmu_ctxs_tbl[mmu_ctxp->mmu_idx]);

        currcnum = sfmmup->sfmmu_ctxs[mmu_ctxp->mmu_idx].cnum;

        pstate_save = sfmmu_disable_intrs();

        lock_set(&sfmmup->sfmmu_ctx_lock);      /* acquire PP lock */
        /* set HAT cnum invalid across all context domains. */
        for (i = 0; i < max_mmu_ctxdoms; i++) {

                cnum = sfmmup->sfmmu_ctxs[i].cnum;
                if (cnum == INVALID_CONTEXT) {
                        continue;
                }

                sfmmup->sfmmu_ctxs[i].cnum = INVALID_CONTEXT;
        }
        membar_enter(); /* make sure globally visible to all CPUs */
        lock_clear(&sfmmup->sfmmu_ctx_lock);    /* release PP lock */

        sfmmu_enable_intrs(pstate_save);

        cpuset = sfmmup->sfmmu_cpusran;
        CPUSET_DEL(cpuset, CPU->cpu_id);
        CPUSET_AND(cpuset, cpu_ready_set);
        if (!CPUSET_ISNULL(cpuset)) {
                SFMMU_XCALL_STATS(sfmmup);
                xt_some(cpuset, sfmmu_raise_tsb_exception,
                    (uint64_t)sfmmup, INVALID_CONTEXT);
                xt_sync(cpuset);
                SFMMU_STAT(sf_tsb_raise_exception);
                SFMMU_MMU_STAT(mmu_tsb_raise_exception);
        }

        /*
         * If the hat to-be-invalidated is the same as the current
         * process on local CPU we need to invalidate
         * this CPU context as well.
         */
        if ((sfmmu_getctx_sec() == currcnum) &&
            (currcnum != INVALID_CONTEXT)) {
                /* sets shared context to INVALID too */
                sfmmu_setctx_sec(INVALID_CONTEXT);
                sfmmu_clear_utsbinfo();
        }

        SFMMU_FLAGS_SET(sfmmup, HAT_ALLCTX_INVALID);

        kpreempt_enable();

        /*
         * we hold the hat lock, so nobody should allocate a context
         * for us yet
         */
        ASSERT(sfmmup->sfmmu_ctxs[mmu_ctxp->mmu_idx].cnum == INVALID_CONTEXT);
}

#ifdef VAC
/*
 * We need to flush the cache in all cpus.  It is possible that
 * a process referenced a page as cacheable but has sinced exited
 * and cleared the mapping list.  We still to flush it but have no
 * state so all cpus is the only alternative.
 */
void
sfmmu_cache_flush(pfn_t pfnum, int vcolor)
{
        cpuset_t cpuset;

        kpreempt_disable();
        cpuset = cpu_ready_set;
        CPUSET_DEL(cpuset, CPU->cpu_id);
        SFMMU_XCALL_STATS(NULL);        /* account to any ctx */
        xt_some(cpuset, vac_flushpage_tl1, pfnum, vcolor);
        xt_sync(cpuset);
        vac_flushpage(pfnum, vcolor);
        kpreempt_enable();
}

void
sfmmu_cache_flushcolor(int vcolor, pfn_t pfnum)
{
        cpuset_t cpuset;

        ASSERT(vcolor >= 0);

        kpreempt_disable();
        cpuset = cpu_ready_set;
        CPUSET_DEL(cpuset, CPU->cpu_id);
        SFMMU_XCALL_STATS(NULL);        /* account to any ctx */
        xt_some(cpuset, vac_flushcolor_tl1, vcolor, pfnum);
        xt_sync(cpuset);
        vac_flushcolor(vcolor, pfnum);
        kpreempt_enable();
}
#endif  /* VAC */

/*
 * We need to prevent processes from accessing the TSB using a cached physical
 * address.  It's alright if they try to access the TSB via virtual address
 * since they will just fault on that virtual address once the mapping has
 * been suspended.
 */
#pragma weak sendmondo_in_recover

/* ARGSUSED */
static int
sfmmu_tsb_pre_relocator(caddr_t va, uint_t tsbsz, uint_t flags, void *tsbinfo)
{
        struct tsb_info *tsbinfop = (struct tsb_info *)tsbinfo;
        sfmmu_t *sfmmup = tsbinfop->tsb_sfmmu;
        hatlock_t *hatlockp;
        sf_scd_t *scdp;

        if (flags != HAT_PRESUSPEND)
                return (0);

        /*
         * If tsb is a shared TSB with TSB_SHAREDCTX set, sfmmup must
         * be a shared hat, then set SCD's tsbinfo's flag.
         * If tsb is not shared, sfmmup is a private hat, then set
         * its private tsbinfo's flag.
         */
        hatlockp = sfmmu_hat_enter(sfmmup);
        tsbinfop->tsb_flags |= TSB_RELOC_FLAG;

        if (!(tsbinfop->tsb_flags & TSB_SHAREDCTX)) {
                sfmmu_tsb_inv_ctx(sfmmup);
                sfmmu_hat_exit(hatlockp);
        } else {
                /* release lock on the shared hat */
                sfmmu_hat_exit(hatlockp);
                /* sfmmup is a shared hat */
                ASSERT(sfmmup->sfmmu_scdhat);
                scdp = sfmmup->sfmmu_scdp;
                ASSERT(scdp != NULL);
                /* get private hat from the scd list */
                mutex_enter(&scdp->scd_mutex);
                sfmmup = scdp->scd_sf_list;
                while (sfmmup != NULL) {
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        /*
                         * We do not call sfmmu_tsb_inv_ctx here because
                         * sendmondo_in_recover check is only needed for
                         * sun4u.
                         */
                        sfmmu_invalidate_ctx(sfmmup);
                        sfmmu_hat_exit(hatlockp);
                        sfmmup = sfmmup->sfmmu_scd_link.next;

                }
                mutex_exit(&scdp->scd_mutex);
        }
        return (0);
}

static void
sfmmu_tsb_inv_ctx(sfmmu_t *sfmmup)
{
        extern uint32_t sendmondo_in_recover;

        ASSERT(sfmmu_hat_lock_held(sfmmup));

        /*
         * For Cheetah+ Erratum 25:
         * Wait for any active recovery to finish.  We can't risk
         * relocating the TSB of the thread running mondo_recover_proc()
         * since, if we did that, we would deadlock.  The scenario we are
         * trying to avoid is as follows:
         *
         * THIS CPU                     RECOVER CPU
         * --------                     -----------
         *                              Begins recovery, walking through TSB
         * hat_pagesuspend() TSB TTE
         *                              TLB miss on TSB TTE, spins at TL1
         * xt_sync()
         *      send_mondo_timeout()
         *      mondo_recover_proc()
         *      ((deadlocked))
         *
         * The second half of the workaround is that mondo_recover_proc()
         * checks to see if the tsb_info has the RELOC flag set, and if it
         * does, it skips over that TSB without ever touching tsbinfop->tsb_va
         * and hence avoiding the TLB miss that could result in a deadlock.
         */
        if (&sendmondo_in_recover) {
                membar_enter(); /* make sure RELOC flag visible */
                while (sendmondo_in_recover) {
                        drv_usecwait(1);
                        membar_consumer();
                }
        }

        sfmmu_invalidate_ctx(sfmmup);
}

/* ARGSUSED */
static int
sfmmu_tsb_post_relocator(caddr_t va, uint_t tsbsz, uint_t flags,
    void *tsbinfo, pfn_t newpfn)
{
        hatlock_t *hatlockp;
        struct tsb_info *tsbinfop = (struct tsb_info *)tsbinfo;
        sfmmu_t *sfmmup = tsbinfop->tsb_sfmmu;

        if (flags != HAT_POSTUNSUSPEND)
                return (0);

        hatlockp = sfmmu_hat_enter(sfmmup);

        SFMMU_STAT(sf_tsb_reloc);

        /*
         * The process may have swapped out while we were relocating one
         * of its TSBs.  If so, don't bother doing the setup since the
         * process can't be using the memory anymore.
         */
        if ((tsbinfop->tsb_flags & TSB_SWAPPED) == 0) {
                ASSERT(va == tsbinfop->tsb_va);
                sfmmu_tsbinfo_setup_phys(tsbinfop, newpfn);

                if (tsbinfop->tsb_flags & TSB_FLUSH_NEEDED) {
                        sfmmu_inv_tsb(tsbinfop->tsb_va,
                            TSB_BYTES(tsbinfop->tsb_szc));
                        tsbinfop->tsb_flags &= ~TSB_FLUSH_NEEDED;
                }
        }

        membar_exit();
        tsbinfop->tsb_flags &= ~TSB_RELOC_FLAG;
        cv_broadcast(&sfmmup->sfmmu_tsb_cv);

        sfmmu_hat_exit(hatlockp);

        return (0);
}

/*
 * Allocate and initialize a tsb_info structure.  Note that we may or may not
 * allocate a TSB here, depending on the flags passed in.
 */
static int
sfmmu_tsbinfo_alloc(struct tsb_info **tsbinfopp, int tsb_szc, int tte_sz_mask,
    uint_t flags, sfmmu_t *sfmmup)
{
        int err;

        *tsbinfopp = (struct tsb_info *)kmem_cache_alloc(
            sfmmu_tsbinfo_cache, KM_SLEEP);

        if ((err = sfmmu_init_tsbinfo(*tsbinfopp, tte_sz_mask,
            tsb_szc, flags, sfmmup)) != 0) {
                kmem_cache_free(sfmmu_tsbinfo_cache, *tsbinfopp);
                SFMMU_STAT(sf_tsb_allocfail);
                *tsbinfopp = NULL;
                return (err);
        }
        SFMMU_STAT(sf_tsb_alloc);

        /*
         * Bump the TSB size counters for this TSB size.
         */
        (*(((int *)&sfmmu_tsbsize_stat) + tsb_szc))++;
        return (0);
}

static void
sfmmu_tsb_free(struct tsb_info *tsbinfo)
{
        caddr_t tsbva = tsbinfo->tsb_va;
        uint_t tsb_size = TSB_BYTES(tsbinfo->tsb_szc);
        struct kmem_cache *kmem_cachep = tsbinfo->tsb_cache;
        vmem_t  *vmp = tsbinfo->tsb_vmp;

        /*
         * If we allocated this TSB from relocatable kernel memory, then we
         * need to uninstall the callback handler.
         */
        if (tsbinfo->tsb_cache != sfmmu_tsb8k_cache) {
                uintptr_t slab_mask;
                caddr_t slab_vaddr;
                page_t **ppl;
                int ret;

                ASSERT(tsb_size <= MMU_PAGESIZE4M || use_bigtsb_arena);
                if (tsb_size > MMU_PAGESIZE4M)
                        slab_mask = ~((uintptr_t)bigtsb_slab_mask) << PAGESHIFT;
                else
                        slab_mask = ~((uintptr_t)tsb_slab_mask) << PAGESHIFT;
                slab_vaddr = (caddr_t)((uintptr_t)tsbva & slab_mask);

                ret = as_pagelock(&kas, &ppl, slab_vaddr, PAGESIZE, S_WRITE);
                ASSERT(ret == 0);
                hat_delete_callback(tsbva, (uint_t)tsb_size, (void *)tsbinfo,
                    0, NULL);
                as_pageunlock(&kas, ppl, slab_vaddr, PAGESIZE, S_WRITE);
        }

        if (kmem_cachep != NULL) {
                kmem_cache_free(kmem_cachep, tsbva);
        } else {
                vmem_xfree(vmp, (void *)tsbva, tsb_size);
        }
        tsbinfo->tsb_va = (caddr_t)0xbad00bad;
        atomic_add_64(&tsb_alloc_bytes, -(int64_t)tsb_size);
}

static void
sfmmu_tsbinfo_free(struct tsb_info *tsbinfo)
{
        if ((tsbinfo->tsb_flags & TSB_SWAPPED) == 0) {
                sfmmu_tsb_free(tsbinfo);
        }
        kmem_cache_free(sfmmu_tsbinfo_cache, tsbinfo);

}

/*
 * Setup all the references to physical memory for this tsbinfo.
 * The underlying page(s) must be locked.
 */
static void
sfmmu_tsbinfo_setup_phys(struct tsb_info *tsbinfo, pfn_t pfn)
{
        ASSERT(pfn != PFN_INVALID);
        ASSERT(pfn == va_to_pfn(tsbinfo->tsb_va));

#ifndef sun4v
        if (tsbinfo->tsb_szc == 0) {
                sfmmu_memtte(&tsbinfo->tsb_tte, pfn,
                    PROT_WRITE|PROT_READ, TTE8K);
        } else {
                /*
                 * Round down PA and use a large mapping; the handlers will
                 * compute the TSB pointer at the correct offset into the
                 * big virtual page.  NOTE: this assumes all TSBs larger
                 * than 8K must come from physically contiguous slabs of
                 * size tsb_slab_size.
                 */
                sfmmu_memtte(&tsbinfo->tsb_tte, pfn & ~tsb_slab_mask,
                    PROT_WRITE|PROT_READ, tsb_slab_ttesz);
        }
        tsbinfo->tsb_pa = ptob(pfn);

        TTE_SET_LOCKED(&tsbinfo->tsb_tte); /* lock the tte into dtlb */
        TTE_SET_MOD(&tsbinfo->tsb_tte);    /* enable writes */

        ASSERT(TTE_IS_PRIVILEGED(&tsbinfo->tsb_tte));
        ASSERT(TTE_IS_LOCKED(&tsbinfo->tsb_tte));
#else /* sun4v */
        tsbinfo->tsb_pa = ptob(pfn);
#endif /* sun4v */
}


/*
 * Returns zero on success, ENOMEM if over the high water mark,
 * or EAGAIN if the caller needs to retry with a smaller TSB
 * size (or specify TSB_FORCEALLOC if the allocation can't fail).
 *
 * This call cannot fail to allocate a TSB if TSB_FORCEALLOC
 * is specified and the TSB requested is PAGESIZE, though it
 * may sleep waiting for memory if sufficient memory is not
 * available.
 */
static int
sfmmu_init_tsbinfo(struct tsb_info *tsbinfo, int tteszmask,
    int tsbcode, uint_t flags, sfmmu_t *sfmmup)
{
        caddr_t vaddr = NULL;
        caddr_t slab_vaddr;
        uintptr_t slab_mask;
        int tsbbytes = TSB_BYTES(tsbcode);
        int lowmem = 0;
        struct kmem_cache *kmem_cachep = NULL;
        vmem_t *vmp = NULL;
        lgrp_id_t lgrpid = LGRP_NONE;
        pfn_t pfn;
        uint_t cbflags = HAC_SLEEP;
        page_t **pplist;
        int ret;

        ASSERT(tsbbytes <= MMU_PAGESIZE4M || use_bigtsb_arena);
        if (tsbbytes > MMU_PAGESIZE4M)
                slab_mask = ~((uintptr_t)bigtsb_slab_mask) << PAGESHIFT;
        else
                slab_mask = ~((uintptr_t)tsb_slab_mask) << PAGESHIFT;

        if (flags & (TSB_FORCEALLOC | TSB_SWAPIN | TSB_GROW | TSB_SHRINK))
                flags |= TSB_ALLOC;

        ASSERT((flags & TSB_FORCEALLOC) == 0 || tsbcode == TSB_MIN_SZCODE);

        tsbinfo->tsb_sfmmu = sfmmup;

        /*
         * If not allocating a TSB, set up the tsbinfo, set TSB_SWAPPED, and
         * return.
         */
        if ((flags & TSB_ALLOC) == 0) {
                tsbinfo->tsb_szc = tsbcode;
                tsbinfo->tsb_ttesz_mask = tteszmask;
                tsbinfo->tsb_va = (caddr_t)0xbadbadbeef;
                tsbinfo->tsb_pa = -1;
                tsbinfo->tsb_tte.ll = 0;
                tsbinfo->tsb_next = NULL;
                tsbinfo->tsb_flags = TSB_SWAPPED;
                tsbinfo->tsb_cache = NULL;
                tsbinfo->tsb_vmp = NULL;
                return (0);
        }

#ifdef DEBUG
        /*
         * For debugging:
         * Randomly force allocation failures every tsb_alloc_mtbf
         * tries if TSB_FORCEALLOC is not specified.  This will
         * return ENOMEM if tsb_alloc_mtbf is odd, or EAGAIN if
         * it is even, to allow testing of both failure paths...
         */
        if (tsb_alloc_mtbf && ((flags & TSB_FORCEALLOC) == 0) &&
            (tsb_alloc_count++ == tsb_alloc_mtbf)) {
                tsb_alloc_count = 0;
                tsb_alloc_fail_mtbf++;
                return ((tsb_alloc_mtbf & 1)? ENOMEM : EAGAIN);
        }
#endif  /* DEBUG */

        /*
         * Enforce high water mark if we are not doing a forced allocation
         * and are not shrinking a process' TSB.
         */
        if ((flags & TSB_SHRINK) == 0 &&
            (tsbbytes + tsb_alloc_bytes) > tsb_alloc_hiwater) {
                if ((flags & TSB_FORCEALLOC) == 0)
                        return (ENOMEM);
                lowmem = 1;
        }

        /*
         * Allocate from the correct location based upon the size of the TSB
         * compared to the base page size, and what memory conditions dictate.
         * Note we always do nonblocking allocations from the TSB arena since
         * we don't want memory fragmentation to cause processes to block
         * indefinitely waiting for memory; until the kernel algorithms that
         * coalesce large pages are improved this is our best option.
         *
         * Algorithm:
         *      If allocating a "large" TSB (>8K), allocate from the
         *              appropriate kmem_tsb_default_arena vmem arena
         *      else if low on memory or the TSB_FORCEALLOC flag is set or
         *      tsb_forceheap is set
         *              Allocate from kernel heap via sfmmu_tsb8k_cache with
         *              KM_SLEEP (never fails)
         *      else
         *              Allocate from appropriate sfmmu_tsb_cache with
         *              KM_NOSLEEP
         *      endif
         */
        if (tsb_lgrp_affinity)
                lgrpid = lgrp_home_id(curthread);
        if (lgrpid == LGRP_NONE)
                lgrpid = 0;     /* use lgrp of boot CPU */

        if (tsbbytes > MMU_PAGESIZE) {
                if (tsbbytes > MMU_PAGESIZE4M) {
                        vmp = kmem_bigtsb_default_arena[lgrpid];
                        vaddr = (caddr_t)vmem_xalloc(vmp, tsbbytes, tsbbytes,
                            0, 0, NULL, NULL, VM_NOSLEEP);
                } else {
                        vmp = kmem_tsb_default_arena[lgrpid];
                        vaddr = (caddr_t)vmem_xalloc(vmp, tsbbytes, tsbbytes,
                            0, 0, NULL, NULL, VM_NOSLEEP);
                }
#ifdef  DEBUG
        } else if (lowmem || (flags & TSB_FORCEALLOC) || tsb_forceheap) {
#else   /* !DEBUG */
        } else if (lowmem || (flags & TSB_FORCEALLOC)) {
#endif  /* DEBUG */
                kmem_cachep = sfmmu_tsb8k_cache;
                vaddr = (caddr_t)kmem_cache_alloc(kmem_cachep, KM_SLEEP);
                ASSERT(vaddr != NULL);
        } else {
                kmem_cachep = sfmmu_tsb_cache[lgrpid];
                vaddr = (caddr_t)kmem_cache_alloc(kmem_cachep, KM_NOSLEEP);
        }

        tsbinfo->tsb_cache = kmem_cachep;
        tsbinfo->tsb_vmp = vmp;

        if (vaddr == NULL) {
                return (EAGAIN);
        }

        atomic_add_64(&tsb_alloc_bytes, (int64_t)tsbbytes);
        kmem_cachep = tsbinfo->tsb_cache;

        /*
         * If we are allocating from outside the cage, then we need to
         * register a relocation callback handler.  Note that for now
         * since pseudo mappings always hang off of the slab's root page,
         * we need only lock the first 8K of the TSB slab.  This is a bit
         * hacky but it is good for performance.
         */
        if (kmem_cachep != sfmmu_tsb8k_cache) {
                slab_vaddr = (caddr_t)((uintptr_t)vaddr & slab_mask);
                ret = as_pagelock(&kas, &pplist, slab_vaddr, PAGESIZE, S_WRITE);
                ASSERT(ret == 0);
                ret = hat_add_callback(sfmmu_tsb_cb_id, vaddr, (uint_t)tsbbytes,
                    cbflags, (void *)tsbinfo, &pfn, NULL);

                /*
                 * Need to free up resources if we could not successfully
                 * add the callback function and return an error condition.
                 */
                if (ret != 0) {
                        if (kmem_cachep) {
                                kmem_cache_free(kmem_cachep, vaddr);
                        } else {
                                vmem_xfree(vmp, (void *)vaddr, tsbbytes);
                        }
                        as_pageunlock(&kas, pplist, slab_vaddr, PAGESIZE,
                            S_WRITE);
                        return (EAGAIN);
                }
        } else {
                /*
                 * Since allocation of 8K TSBs from heap is rare and occurs
                 * during memory pressure we allocate them from permanent
                 * memory rather than using callbacks to get the PFN.
                 */
                pfn = hat_getpfnum(kas.a_hat, vaddr);
        }

        tsbinfo->tsb_va = vaddr;
        tsbinfo->tsb_szc = tsbcode;
        tsbinfo->tsb_ttesz_mask = tteszmask;
        tsbinfo->tsb_next = NULL;
        tsbinfo->tsb_flags = 0;

        sfmmu_tsbinfo_setup_phys(tsbinfo, pfn);

        sfmmu_inv_tsb(vaddr, tsbbytes);

        if (kmem_cachep != sfmmu_tsb8k_cache) {
                as_pageunlock(&kas, pplist, slab_vaddr, PAGESIZE, S_WRITE);
        }

        return (0);
}

/*
 * Initialize per cpu tsb and per cpu tsbmiss_area
 */
void
sfmmu_init_tsbs(void)
{
        int i;
        struct tsbmiss  *tsbmissp;
        struct kpmtsbm  *kpmtsbmp;
#ifndef sun4v
        extern int      dcache_line_mask;
#endif /* sun4v */
        extern uint_t   vac_colors;

        /*
         * Init. tsb miss area.
         */
        tsbmissp = tsbmiss_area;

        for (i = 0; i < NCPU; tsbmissp++, i++) {
                /*
                 * initialize the tsbmiss area.
                 * Do this for all possible CPUs as some may be added
                 * while the system is running. There is no cost to this.
                 */
                tsbmissp->ksfmmup = ksfmmup;
#ifndef sun4v
                tsbmissp->dcache_line_mask = (uint16_t)dcache_line_mask;
#endif /* sun4v */
                tsbmissp->khashstart =
                    (struct hmehash_bucket *)va_to_pa((caddr_t)khme_hash);
                tsbmissp->uhashstart =
                    (struct hmehash_bucket *)va_to_pa((caddr_t)uhme_hash);
                tsbmissp->khashsz = khmehash_num;
                tsbmissp->uhashsz = uhmehash_num;
        }

        sfmmu_tsb_cb_id = hat_register_callback('T'<<16 | 'S' << 8 | 'B',
            sfmmu_tsb_pre_relocator, sfmmu_tsb_post_relocator, NULL, 0);

        if (kpm_enable == 0)
                return;

        /* -- Begin KPM specific init -- */

        if (kpm_smallpages) {
                /*
                 * If we're using base pagesize pages for seg_kpm
                 * mappings, we use the kernel TSB since we can't afford
                 * to allocate a second huge TSB for these mappings.
                 */
                kpm_tsbbase = ktsb_phys? ktsb_pbase : (uint64_t)ktsb_base;
                kpm_tsbsz = ktsb_szcode;
                kpmsm_tsbbase = kpm_tsbbase;
                kpmsm_tsbsz = kpm_tsbsz;
        } else {
                /*
                 * In VAC conflict case, just put the entries in the
                 * kernel 8K indexed TSB for now so we can find them.
                 * This could really be changed in the future if we feel
                 * the need...
                 */
                kpmsm_tsbbase = ktsb_phys? ktsb_pbase : (uint64_t)ktsb_base;
                kpmsm_tsbsz = ktsb_szcode;
                kpm_tsbbase = ktsb_phys? ktsb4m_pbase : (uint64_t)ktsb4m_base;
                kpm_tsbsz = ktsb4m_szcode;
        }

        kpmtsbmp = kpmtsbm_area;
        for (i = 0; i < NCPU; kpmtsbmp++, i++) {
                /*
                 * Initialize the kpmtsbm area.
                 * Do this for all possible CPUs as some may be added
                 * while the system is running. There is no cost to this.
                 */
                kpmtsbmp->vbase = kpm_vbase;
                kpmtsbmp->vend = kpm_vbase + kpm_size * vac_colors;
                kpmtsbmp->sz_shift = kpm_size_shift;
                kpmtsbmp->kpmp_shift = kpmp_shift;
                kpmtsbmp->kpmp2pshft = (uchar_t)kpmp2pshft;
                if (kpm_smallpages == 0) {
                        kpmtsbmp->kpmp_table_sz = kpmp_table_sz;
                        kpmtsbmp->kpmp_tablepa = va_to_pa(kpmp_table);
                } else {
                        kpmtsbmp->kpmp_table_sz = kpmp_stable_sz;
                        kpmtsbmp->kpmp_tablepa = va_to_pa(kpmp_stable);
                }
                kpmtsbmp->msegphashpa = va_to_pa(memseg_phash);
                kpmtsbmp->flags = KPMTSBM_ENABLE_FLAG;
#ifdef  DEBUG
                kpmtsbmp->flags |= (kpm_tsbmtl) ?  KPMTSBM_TLTSBM_FLAG : 0;
#endif  /* DEBUG */
                if (ktsb_phys)
                        kpmtsbmp->flags |= KPMTSBM_TSBPHYS_FLAG;
        }

        /* -- End KPM specific init -- */
}

/* Avoid using sfmmu_tsbinfo_alloc() to avoid kmem_alloc - no real reason */
struct tsb_info ktsb_info[2];

/*
 * Called from hat_kern_setup() to setup the tsb_info for ksfmmup.
 */
void
sfmmu_init_ktsbinfo()
{
        ASSERT(ksfmmup != NULL);
        ASSERT(ksfmmup->sfmmu_tsb == NULL);
        /*
         * Allocate tsbinfos for kernel and copy in data
         * to make debug easier and sun4v setup easier.
         */
        ktsb_info[0].tsb_sfmmu = ksfmmup;
        ktsb_info[0].tsb_szc = ktsb_szcode;
        ktsb_info[0].tsb_ttesz_mask = TSB8K|TSB64K|TSB512K;
        ktsb_info[0].tsb_va = ktsb_base;
        ktsb_info[0].tsb_pa = ktsb_pbase;
        ktsb_info[0].tsb_flags = 0;
        ktsb_info[0].tsb_tte.ll = 0;
        ktsb_info[0].tsb_cache = NULL;

        ktsb_info[1].tsb_sfmmu = ksfmmup;
        ktsb_info[1].tsb_szc = ktsb4m_szcode;
        ktsb_info[1].tsb_ttesz_mask = TSB4M;
        ktsb_info[1].tsb_va = ktsb4m_base;
        ktsb_info[1].tsb_pa = ktsb4m_pbase;
        ktsb_info[1].tsb_flags = 0;
        ktsb_info[1].tsb_tte.ll = 0;
        ktsb_info[1].tsb_cache = NULL;

        /* Link them into ksfmmup. */
        ktsb_info[0].tsb_next = &ktsb_info[1];
        ktsb_info[1].tsb_next = NULL;
        ksfmmup->sfmmu_tsb = &ktsb_info[0];

        sfmmu_setup_tsbinfo(ksfmmup);
}

/*
 * Cache the last value returned from va_to_pa().  If the VA specified
 * in the current call to cached_va_to_pa() maps to the same Page (as the
 * previous call to cached_va_to_pa()), then compute the PA using
 * cached info, else call va_to_pa().
 *
 * Note: this function is neither MT-safe nor consistent in the presence
 * of multiple, interleaved threads.  This function was created to enable
 * an optimization used during boot (at a point when there's only one thread
 * executing on the "boot CPU", and before startup_vm() has been called).
 */
static uint64_t
cached_va_to_pa(void *vaddr)
{
        static uint64_t prev_vaddr_base = 0;
        static uint64_t prev_pfn = 0;

        if ((((uint64_t)vaddr) & MMU_PAGEMASK) == prev_vaddr_base) {
                return (prev_pfn | ((uint64_t)vaddr & MMU_PAGEOFFSET));
        } else {
                uint64_t pa = va_to_pa(vaddr);

                if (pa != ((uint64_t)-1)) {
                        /*
                         * Computed physical address is valid.  Cache its
                         * related info for the next cached_va_to_pa() call.
                         */
                        prev_pfn = pa & MMU_PAGEMASK;
                        prev_vaddr_base = ((uint64_t)vaddr) & MMU_PAGEMASK;
                }

                return (pa);
        }
}

/*
 * Carve up our nucleus hblk region.  We may allocate more hblks than
 * asked due to rounding errors but we are guaranteed to have at least
 * enough space to allocate the requested number of hblk8's and hblk1's.
 */
void
sfmmu_init_nucleus_hblks(caddr_t addr, size_t size, int nhblk8, int nhblk1)
{
        struct hme_blk *hmeblkp;
        size_t hme8blk_sz, hme1blk_sz;
        size_t i;
        size_t hblk8_bound;
        ulong_t j = 0, k = 0;

        ASSERT(addr != NULL && size != 0);

        /* Need to use proper structure alignment */
        hme8blk_sz = roundup(HME8BLK_SZ, sizeof (int64_t));
        hme1blk_sz = roundup(HME1BLK_SZ, sizeof (int64_t));

        nucleus_hblk8.list = (void *)addr;
        nucleus_hblk8.index = 0;

        /*
         * Use as much memory as possible for hblk8's since we
         * expect all bop_alloc'ed memory to be allocated in 8k chunks.
         * We need to hold back enough space for the hblk1's which
         * we'll allocate next.
         */
        hblk8_bound = size - (nhblk1 * hme1blk_sz) - hme8blk_sz;
        for (i = 0; i <= hblk8_bound; i += hme8blk_sz, j++) {
                hmeblkp = (struct hme_blk *)addr;
                addr += hme8blk_sz;
                hmeblkp->hblk_nuc_bit = 1;
                hmeblkp->hblk_nextpa = cached_va_to_pa((caddr_t)hmeblkp);
        }
        nucleus_hblk8.len = j;
        ASSERT(j >= nhblk8);
        SFMMU_STAT_ADD(sf_hblk8_ncreate, j);

        nucleus_hblk1.list = (void *)addr;
        nucleus_hblk1.index = 0;
        for (; i <= (size - hme1blk_sz); i += hme1blk_sz, k++) {
                hmeblkp = (struct hme_blk *)addr;
                addr += hme1blk_sz;
                hmeblkp->hblk_nuc_bit = 1;
                hmeblkp->hblk_nextpa = cached_va_to_pa((caddr_t)hmeblkp);
        }
        ASSERT(k >= nhblk1);
        nucleus_hblk1.len = k;
        SFMMU_STAT_ADD(sf_hblk1_ncreate, k);
}

/*
 * This function is currently not supported on this platform. For what
 * it's supposed to do, see hat.c and hat_srmmu.c
 */
/* ARGSUSED */
faultcode_t
hat_softlock(struct hat *hat, caddr_t addr, size_t *lenp, page_t **ppp,
    uint_t flags)
{
        return (FC_NOSUPPORT);
}

/*
 * Searchs the mapping list of the page for a mapping of the same size. If not
 * found the corresponding bit is cleared in the p_index field. When large
 * pages are more prevalent in the system, we can maintain the mapping list
 * in order and we don't have to traverse the list each time. Just check the
 * next and prev entries, and if both are of different size, we clear the bit.
 */
static void
sfmmu_rm_large_mappings(page_t *pp, int ttesz)
{
        struct sf_hment *sfhmep;
        int     index;
        pgcnt_t npgs;

        ASSERT(ttesz > TTE8K);

        ASSERT(sfmmu_mlist_held(pp));

        ASSERT(PP_ISMAPPED_LARGE(pp));

        /*
         * Traverse mapping list looking for another mapping of same size.
         * since we only want to clear index field if all mappings of
         * that size are gone.
         */

        for (sfhmep = pp->p_mapping; sfhmep; sfhmep = sfhmep->hme_next) {
                if (IS_PAHME(sfhmep))
                        continue;
                if (hme_size(sfhmep) == ttesz) {
                        /*
                         * another mapping of the same size. don't clear index.
                         */
                        return;
                }
        }

        /*
         * Clear the p_index bit for large page.
         */
        index = PAGESZ_TO_INDEX(ttesz);
        npgs = TTEPAGES(ttesz);
        while (npgs-- > 0) {
                ASSERT(pp->p_index & index);
                pp->p_index &= ~index;
                pp = PP_PAGENEXT(pp);
        }
}

/*
 * return supported features
 */
/* ARGSUSED */
int
hat_supported(enum hat_features feature, void *arg)
{
        switch (feature) {
        case    HAT_SHARED_PT:
        case    HAT_DYNAMIC_ISM_UNMAP:
        case    HAT_VMODSORT:
                return (1);
        case    HAT_SHARED_REGIONS:
                if (shctx_on)
                        return (1);
                else
                        return (0);
        default:
                return (0);
        }
}

void
hat_enter(struct hat *hat)
{
        hatlock_t       *hatlockp;

        if (hat != ksfmmup) {
                hatlockp = TSB_HASH(hat);
                mutex_enter(HATLOCK_MUTEXP(hatlockp));
        }
}

void
hat_exit(struct hat *hat)
{
        hatlock_t       *hatlockp;

        if (hat != ksfmmup) {
                hatlockp = TSB_HASH(hat);
                mutex_exit(HATLOCK_MUTEXP(hatlockp));
        }
}

/*ARGSUSED*/
void
hat_reserve(struct as *as, caddr_t addr, size_t len)
{
}

static void
hat_kstat_init(void)
{
        kstat_t *ksp;

        ksp = kstat_create("unix", 0, "sfmmu_global_stat", "hat",
            KSTAT_TYPE_RAW, sizeof (struct sfmmu_global_stat),
            KSTAT_FLAG_VIRTUAL);
        if (ksp) {
                ksp->ks_data = (void *) &sfmmu_global_stat;
                kstat_install(ksp);
        }
        ksp = kstat_create("unix", 0, "sfmmu_tsbsize_stat", "hat",
            KSTAT_TYPE_RAW, sizeof (struct sfmmu_tsbsize_stat),
            KSTAT_FLAG_VIRTUAL);
        if (ksp) {
                ksp->ks_data = (void *) &sfmmu_tsbsize_stat;
                kstat_install(ksp);
        }
        ksp = kstat_create("unix", 0, "sfmmu_percpu_stat", "hat",
            KSTAT_TYPE_RAW, sizeof (struct sfmmu_percpu_stat) * NCPU,
            KSTAT_FLAG_WRITABLE);
        if (ksp) {
                ksp->ks_update = sfmmu_kstat_percpu_update;
                kstat_install(ksp);
        }
}

/* ARGSUSED */
static int
sfmmu_kstat_percpu_update(kstat_t *ksp, int rw)
{
        struct sfmmu_percpu_stat *cpu_kstat = ksp->ks_data;
        struct tsbmiss *tsbm = tsbmiss_area;
        struct kpmtsbm *kpmtsbm = kpmtsbm_area;
        int i;

        ASSERT(cpu_kstat);
        if (rw == KSTAT_READ) {
                for (i = 0; i < NCPU; cpu_kstat++, tsbm++, kpmtsbm++, i++) {
                        cpu_kstat->sf_itlb_misses = 0;
                        cpu_kstat->sf_dtlb_misses = 0;
                        cpu_kstat->sf_utsb_misses = tsbm->utsb_misses -
                            tsbm->uprot_traps;
                        cpu_kstat->sf_ktsb_misses = tsbm->ktsb_misses +
                            kpmtsbm->kpm_tsb_misses - tsbm->kprot_traps;
                        cpu_kstat->sf_tsb_hits = 0;
                        cpu_kstat->sf_umod_faults = tsbm->uprot_traps;
                        cpu_kstat->sf_kmod_faults = tsbm->kprot_traps;
                }
        } else {
                /* KSTAT_WRITE is used to clear stats */
                for (i = 0; i < NCPU; tsbm++, kpmtsbm++, i++) {
                        tsbm->utsb_misses = 0;
                        tsbm->ktsb_misses = 0;
                        tsbm->uprot_traps = 0;
                        tsbm->kprot_traps = 0;
                        kpmtsbm->kpm_dtlb_misses = 0;
                        kpmtsbm->kpm_tsb_misses = 0;
                }
        }
        return (0);
}

#ifdef  DEBUG

tte_t  *gorig[NCPU], *gcur[NCPU], *gnew[NCPU];

/*
 * A tte checker. *orig_old is the value we read before cas.
 *      *cur is the value returned by cas.
 *      *new is the desired value when we do the cas.
 *
 *      *hmeblkp is currently unused.
 */

/* ARGSUSED */
void
chk_tte(tte_t *orig_old, tte_t *cur, tte_t *new, struct hme_blk *hmeblkp)
{
        pfn_t i, j, k;
        int cpuid = CPU->cpu_id;

        gorig[cpuid] = orig_old;
        gcur[cpuid] = cur;
        gnew[cpuid] = new;

#ifdef lint
        hmeblkp = hmeblkp;
#endif

        if (TTE_IS_VALID(orig_old)) {
                if (TTE_IS_VALID(cur)) {
                        i = TTE_TO_TTEPFN(orig_old);
                        j = TTE_TO_TTEPFN(cur);
                        k = TTE_TO_TTEPFN(new);
                        if (i != j) {
                                /* remap error? */
                                panic("chk_tte: bad pfn, 0x%lx, 0x%lx", i, j);
                        }

                        if (i != k) {
                                /* remap error? */
                                panic("chk_tte: bad pfn2, 0x%lx, 0x%lx", i, k);
                        }
                } else {
                        if (TTE_IS_VALID(new)) {
                                panic("chk_tte: invalid cur? ");
                        }

                        i = TTE_TO_TTEPFN(orig_old);
                        k = TTE_TO_TTEPFN(new);
                        if (i != k) {
                                panic("chk_tte: bad pfn3, 0x%lx, 0x%lx", i, k);
                        }
                }
        } else {
                if (TTE_IS_VALID(cur)) {
                        j = TTE_TO_TTEPFN(cur);
                        if (TTE_IS_VALID(new)) {
                                k = TTE_TO_TTEPFN(new);
                                if (j != k) {
                                        panic("chk_tte: bad pfn4, 0x%lx, 0x%lx",
                                            j, k);
                                }
                        } else {
                                panic("chk_tte: why here?");
                        }
                } else {
                        if (!TTE_IS_VALID(new)) {
                                panic("chk_tte: why here2 ?");
                        }
                }
        }
}

#endif /* DEBUG */

extern void prefetch_tsbe_read(struct tsbe *);
extern void prefetch_tsbe_write(struct tsbe *);


/*
 * We want to prefetch 7 cache lines ahead for our read prefetch.  This gives
 * us optimal performance on Cheetah+.  You can only have 8 outstanding
 * prefetches at any one time, so we opted for 7 read prefetches and 1 write
 * prefetch to make the most utilization of the prefetch capability.
 */
#define TSBE_PREFETCH_STRIDE (7)

void
sfmmu_copy_tsb(struct tsb_info *old_tsbinfo, struct tsb_info *new_tsbinfo)
{
        int old_bytes = TSB_BYTES(old_tsbinfo->tsb_szc);
        int new_bytes = TSB_BYTES(new_tsbinfo->tsb_szc);
        int old_entries = TSB_ENTRIES(old_tsbinfo->tsb_szc);
        int new_entries = TSB_ENTRIES(new_tsbinfo->tsb_szc);
        struct tsbe *old;
        struct tsbe *new;
        struct tsbe *new_base = (struct tsbe *)new_tsbinfo->tsb_va;
        uint64_t va;
        int new_offset;
        int i;
        int vpshift;
        int last_prefetch;

        if (old_bytes == new_bytes) {
                bcopy(old_tsbinfo->tsb_va, new_tsbinfo->tsb_va, new_bytes);
        } else {

                /*
                 * A TSBE is 16 bytes which means there are four TSBE's per
                 * P$ line (64 bytes), thus every 4 TSBE's we prefetch.
                 */
                old = (struct tsbe *)old_tsbinfo->tsb_va;
                last_prefetch = old_entries - (4*(TSBE_PREFETCH_STRIDE+1));
                for (i = 0; i < old_entries; i++, old++) {
                        if (((i & (4-1)) == 0) && (i < last_prefetch))
                                prefetch_tsbe_read(old);
                        if (!old->tte_tag.tag_invalid) {
                                /*
                                 * We have a valid TTE to remap.  Check the
                                 * size.  We won't remap 64K or 512K TTEs
                                 * because they span more than one TSB entry
                                 * and are indexed using an 8K virt. page.
                                 * Ditto for 32M and 256M TTEs.
                                 */
                                if (TTE_CSZ(&old->tte_data) == TTE64K ||
                                    TTE_CSZ(&old->tte_data) == TTE512K)
                                        continue;
                                if (mmu_page_sizes == max_mmu_page_sizes) {
                                        if (TTE_CSZ(&old->tte_data) == TTE32M ||
                                            TTE_CSZ(&old->tte_data) == TTE256M)
                                                continue;
                                }

                                /* clear the lower 22 bits of the va */
                                va = *(uint64_t *)old << 22;
                                /* turn va into a virtual pfn */
                                va >>= 22 - TSB_START_SIZE;
                                /*
                                 * or in bits from the offset in the tsb
                                 * to get the real virtual pfn. These
                                 * correspond to bits [21:13] in the va
                                 */
                                vpshift =
                                    TTE_BSZS_SHIFT(TTE_CSZ(&old->tte_data)) &
                                    0x1ff;
                                va |= (i << vpshift);
                                va >>= vpshift;
                                new_offset = va & (new_entries - 1);
                                new = new_base + new_offset;
                                prefetch_tsbe_write(new);
                                *new = *old;
                        }
                }
        }
}

/*
 * unused in sfmmu
 */
void
hat_dump(void)
{
}

/*
 * Called when a thread is exiting and we have switched to the kernel address
 * space.  Perform the same VM initialization resume() uses when switching
 * processes.
 *
 * Note that sfmmu_load_mmustate() is currently a no-op for kernel threads, but
 * we call it anyway in case the semantics change in the future.
 */
/*ARGSUSED*/
void
hat_thread_exit(kthread_t *thd)
{
        uint_t pgsz_cnum;
        uint_t pstate_save;

        ASSERT(thd->t_procp->p_as == &kas);

        pgsz_cnum = KCONTEXT;
#ifdef sun4u
        pgsz_cnum |= (ksfmmup->sfmmu_cext << CTXREG_EXT_SHIFT);
#endif

        /*
         * Note that sfmmu_load_mmustate() is currently a no-op for
         * kernel threads. We need to disable interrupts here,
         * simply because otherwise sfmmu_load_mmustate() would panic
         * if the caller does not disable interrupts.
         */
        pstate_save = sfmmu_disable_intrs();

        /* Compatibility Note: hw takes care of MMU_SCONTEXT1 */
        sfmmu_setctx_sec(pgsz_cnum);
        sfmmu_load_mmustate(ksfmmup);
        sfmmu_enable_intrs(pstate_save);
}


/*
 * SRD support
 */
#define SRD_HASH_FUNCTION(vp)   (((((uintptr_t)(vp)) >> 4) ^ \
                                    (((uintptr_t)(vp)) >> 11)) & \
                                    srd_hashmask)

/*
 * Attach the process to the srd struct associated with the exec vnode
 * from which the process is started.
 */
void
hat_join_srd(struct hat *sfmmup, vnode_t *evp)
{
        uint_t hash = SRD_HASH_FUNCTION(evp);
        sf_srd_t *srdp;
        sf_srd_t *newsrdp;

        ASSERT(sfmmup != ksfmmup);
        ASSERT(sfmmup->sfmmu_srdp == NULL);

        if (!shctx_on) {
                return;
        }

        VN_HOLD(evp);

        if (srd_buckets[hash].srdb_srdp != NULL) {
                mutex_enter(&srd_buckets[hash].srdb_lock);
                for (srdp = srd_buckets[hash].srdb_srdp; srdp != NULL;
                    srdp = srdp->srd_hash) {
                        if (srdp->srd_evp == evp) {
                                ASSERT(srdp->srd_refcnt >= 0);
                                sfmmup->sfmmu_srdp = srdp;
                                atomic_inc_32(
                                    (volatile uint_t *)&srdp->srd_refcnt);
                                mutex_exit(&srd_buckets[hash].srdb_lock);
                                return;
                        }
                }
                mutex_exit(&srd_buckets[hash].srdb_lock);
        }
        newsrdp = kmem_cache_alloc(srd_cache, KM_SLEEP);
        ASSERT(newsrdp->srd_next_ismrid == 0 && newsrdp->srd_next_hmerid == 0);

        newsrdp->srd_evp = evp;
        newsrdp->srd_refcnt = 1;
        newsrdp->srd_hmergnfree = NULL;
        newsrdp->srd_ismrgnfree = NULL;

        mutex_enter(&srd_buckets[hash].srdb_lock);
        for (srdp = srd_buckets[hash].srdb_srdp; srdp != NULL;
            srdp = srdp->srd_hash) {
                if (srdp->srd_evp == evp) {
                        ASSERT(srdp->srd_refcnt >= 0);
                        sfmmup->sfmmu_srdp = srdp;
                        atomic_inc_32((volatile uint_t *)&srdp->srd_refcnt);
                        mutex_exit(&srd_buckets[hash].srdb_lock);
                        kmem_cache_free(srd_cache, newsrdp);
                        return;
                }
        }
        newsrdp->srd_hash = srd_buckets[hash].srdb_srdp;
        srd_buckets[hash].srdb_srdp = newsrdp;
        sfmmup->sfmmu_srdp = newsrdp;

        mutex_exit(&srd_buckets[hash].srdb_lock);

}

static void
sfmmu_leave_srd(sfmmu_t *sfmmup)
{
        vnode_t *evp;
        sf_srd_t *srdp = sfmmup->sfmmu_srdp;
        uint_t hash;
        sf_srd_t **prev_srdpp;
        sf_region_t *rgnp;
        sf_region_t *nrgnp;
#ifdef DEBUG
        int rgns = 0;
#endif
        int i;

        ASSERT(sfmmup != ksfmmup);
        ASSERT(srdp != NULL);
        ASSERT(srdp->srd_refcnt > 0);
        ASSERT(sfmmup->sfmmu_scdp == NULL);
        ASSERT(sfmmup->sfmmu_free == 1);

        sfmmup->sfmmu_srdp = NULL;
        evp = srdp->srd_evp;
        ASSERT(evp != NULL);
        if (atomic_dec_32_nv((volatile uint_t *)&srdp->srd_refcnt)) {
                VN_RELE(evp);
                return;
        }

        hash = SRD_HASH_FUNCTION(evp);
        mutex_enter(&srd_buckets[hash].srdb_lock);
        for (prev_srdpp = &srd_buckets[hash].srdb_srdp;
            (srdp = *prev_srdpp) != NULL; prev_srdpp = &srdp->srd_hash) {
                if (srdp->srd_evp == evp) {
                        break;
                }
        }
        if (srdp == NULL || srdp->srd_refcnt) {
                mutex_exit(&srd_buckets[hash].srdb_lock);
                VN_RELE(evp);
                return;
        }
        *prev_srdpp = srdp->srd_hash;
        mutex_exit(&srd_buckets[hash].srdb_lock);

        ASSERT(srdp->srd_refcnt == 0);
        VN_RELE(evp);

#ifdef DEBUG
        for (i = 0; i < SFMMU_MAX_REGION_BUCKETS; i++) {
                ASSERT(srdp->srd_rgnhash[i] == NULL);
        }
#endif /* DEBUG */

        /* free each hme regions in the srd */
        for (rgnp = srdp->srd_hmergnfree; rgnp != NULL; rgnp = nrgnp) {
                nrgnp = rgnp->rgn_next;
                ASSERT(rgnp->rgn_id < srdp->srd_next_hmerid);
                ASSERT(rgnp->rgn_refcnt == 0);
                ASSERT(rgnp->rgn_sfmmu_head == NULL);
                ASSERT(rgnp->rgn_flags & SFMMU_REGION_FREE);
                ASSERT(rgnp->rgn_hmeflags == 0);
                ASSERT(srdp->srd_hmergnp[rgnp->rgn_id] == rgnp);
#ifdef DEBUG
                for (i = 0; i < MMU_PAGE_SIZES; i++) {
                        ASSERT(rgnp->rgn_ttecnt[i] == 0);
                }
                rgns++;
#endif /* DEBUG */
                kmem_cache_free(region_cache, rgnp);
        }
        ASSERT(rgns == srdp->srd_next_hmerid);

#ifdef DEBUG
        rgns = 0;
#endif
        /* free each ism rgns in the srd */
        for (rgnp = srdp->srd_ismrgnfree; rgnp != NULL; rgnp = nrgnp) {
                nrgnp = rgnp->rgn_next;
                ASSERT(rgnp->rgn_id < srdp->srd_next_ismrid);
                ASSERT(rgnp->rgn_refcnt == 0);
                ASSERT(rgnp->rgn_sfmmu_head == NULL);
                ASSERT(rgnp->rgn_flags & SFMMU_REGION_FREE);
                ASSERT(srdp->srd_ismrgnp[rgnp->rgn_id] == rgnp);
#ifdef DEBUG
                for (i = 0; i < MMU_PAGE_SIZES; i++) {
                        ASSERT(rgnp->rgn_ttecnt[i] == 0);
                }
                rgns++;
#endif /* DEBUG */
                kmem_cache_free(region_cache, rgnp);
        }
        ASSERT(rgns == srdp->srd_next_ismrid);
        ASSERT(srdp->srd_ismbusyrgns == 0);
        ASSERT(srdp->srd_hmebusyrgns == 0);

        srdp->srd_next_ismrid = 0;
        srdp->srd_next_hmerid = 0;

        bzero((void *)srdp->srd_ismrgnp,
            sizeof (sf_region_t *) * SFMMU_MAX_ISM_REGIONS);
        bzero((void *)srdp->srd_hmergnp,
            sizeof (sf_region_t *) * SFMMU_MAX_HME_REGIONS);

        ASSERT(srdp->srd_scdp == NULL);
        kmem_cache_free(srd_cache, srdp);
}

/* ARGSUSED */
static int
sfmmu_srdcache_constructor(void *buf, void *cdrarg, int kmflags)
{
        sf_srd_t *srdp = (sf_srd_t *)buf;
        bzero(buf, sizeof (*srdp));

        mutex_init(&srdp->srd_mutex, NULL, MUTEX_DEFAULT, NULL);
        mutex_init(&srdp->srd_scd_mutex, NULL, MUTEX_DEFAULT, NULL);
        return (0);
}

/* ARGSUSED */
static void
sfmmu_srdcache_destructor(void *buf, void *cdrarg)
{
        sf_srd_t *srdp = (sf_srd_t *)buf;

        mutex_destroy(&srdp->srd_mutex);
        mutex_destroy(&srdp->srd_scd_mutex);
}

/*
 * The caller makes sure hat_join_region()/hat_leave_region() can't be called
 * at the same time for the same process and address range. This is ensured by
 * the fact that address space is locked as writer when a process joins the
 * regions. Therefore there's no need to hold an srd lock during the entire
 * execution of hat_join_region()/hat_leave_region().
 */

#define RGN_HASH_FUNCTION(obj)  (((((uintptr_t)(obj)) >> 4) ^ \
                                    (((uintptr_t)(obj)) >> 11)) & \
                                        srd_rgn_hashmask)
/*
 * This routine implements the shared context functionality required when
 * attaching a segment to an address space. It must be called from
 * hat_share() for D(ISM) segments and from segvn_create() for segments
 * with the MAP_PRIVATE and MAP_TEXT flags set. It returns a region_cookie
 * which is saved in the private segment data for hme segments and
 * the ism_map structure for ism segments.
 */
hat_region_cookie_t
hat_join_region(struct hat *sfmmup, caddr_t r_saddr, size_t r_size,
    void *r_obj, u_offset_t r_objoff, uchar_t r_perm, uchar_t r_pgszc,
    hat_rgn_cb_func_t r_cb_function, uint_t flags)
{
        sf_srd_t *srdp = sfmmup->sfmmu_srdp;
        uint_t rhash;
        uint_t rid;
        hatlock_t *hatlockp;
        sf_region_t *rgnp;
        sf_region_t *new_rgnp = NULL;
        int i;
        uint16_t *nextidp;
        sf_region_t **freelistp;
        int maxids;
        sf_region_t **rarrp;
        uint16_t *busyrgnsp;
        ulong_t rttecnt;
        uchar_t tteflag;
        uchar_t r_type = flags & HAT_REGION_TYPE_MASK;
        int text = (r_type == HAT_REGION_TEXT);

        if (srdp == NULL || r_size == 0) {
                return (HAT_INVALID_REGION_COOKIE);
        }

        ASSERT(sfmmup != ksfmmup);
        ASSERT(AS_WRITE_HELD(sfmmup->sfmmu_as));
        ASSERT(srdp->srd_refcnt > 0);
        ASSERT(!(flags & ~HAT_REGION_TYPE_MASK));
        ASSERT(flags == HAT_REGION_TEXT || flags == HAT_REGION_ISM);
        ASSERT(r_pgszc < mmu_page_sizes);
        if (!IS_P2ALIGNED(r_saddr, TTEBYTES(r_pgszc)) ||
            !IS_P2ALIGNED(r_size, TTEBYTES(r_pgszc))) {
                panic("hat_join_region: region addr or size is not aligned\n");
        }


        r_type = (r_type == HAT_REGION_ISM) ? SFMMU_REGION_ISM :
            SFMMU_REGION_HME;
        /*
         * Currently only support shared hmes for the read only main text
         * region.
         */
        if (r_type == SFMMU_REGION_HME && ((r_obj != srdp->srd_evp) ||
            (r_perm & PROT_WRITE))) {
                return (HAT_INVALID_REGION_COOKIE);
        }

        rhash = RGN_HASH_FUNCTION(r_obj);

        if (r_type == SFMMU_REGION_ISM) {
                nextidp = &srdp->srd_next_ismrid;
                freelistp = &srdp->srd_ismrgnfree;
                maxids = SFMMU_MAX_ISM_REGIONS;
                rarrp = srdp->srd_ismrgnp;
                busyrgnsp = &srdp->srd_ismbusyrgns;
        } else {
                nextidp = &srdp->srd_next_hmerid;
                freelistp = &srdp->srd_hmergnfree;
                maxids = SFMMU_MAX_HME_REGIONS;
                rarrp = srdp->srd_hmergnp;
                busyrgnsp = &srdp->srd_hmebusyrgns;
        }

        mutex_enter(&srdp->srd_mutex);

        for (rgnp = srdp->srd_rgnhash[rhash]; rgnp != NULL;
            rgnp = rgnp->rgn_hash) {
                if (rgnp->rgn_saddr == r_saddr && rgnp->rgn_size == r_size &&
                    rgnp->rgn_obj == r_obj && rgnp->rgn_objoff == r_objoff &&
                    rgnp->rgn_perm == r_perm && rgnp->rgn_pgszc == r_pgszc) {
                        break;
                }
        }

rfound:
        if (rgnp != NULL) {
                ASSERT((rgnp->rgn_flags & SFMMU_REGION_TYPE_MASK) == r_type);
                ASSERT(rgnp->rgn_cb_function == r_cb_function);
                ASSERT(rgnp->rgn_refcnt >= 0);
                rid = rgnp->rgn_id;
                ASSERT(rid < maxids);
                ASSERT(rarrp[rid] == rgnp);
                ASSERT(rid < *nextidp);
                atomic_inc_32((volatile uint_t *)&rgnp->rgn_refcnt);
                mutex_exit(&srdp->srd_mutex);
                if (new_rgnp != NULL) {
                        kmem_cache_free(region_cache, new_rgnp);
                }
                if (r_type == SFMMU_REGION_HME) {
                        int myjoin =
                            (sfmmup == astosfmmu(curthread->t_procp->p_as));

                        sfmmu_link_to_hmeregion(sfmmup, rgnp);
                        /*
                         * bitmap should be updated after linking sfmmu on
                         * region list so that pageunload() doesn't skip
                         * TSB/TLB flush. As soon as bitmap is updated another
                         * thread in this process can already start accessing
                         * this region.
                         */
                        /*
                         * Normally ttecnt accounting is done as part of
                         * pagefault handling. But a process may not take any
                         * pagefaults on shared hmeblks created by some other
                         * process. To compensate for this assume that the
                         * entire region will end up faulted in using
                         * the region's pagesize.
                         *
                         */
                        if (r_pgszc > TTE8K) {
                                tteflag = 1 << r_pgszc;
                                if (disable_large_pages & tteflag) {
                                        tteflag = 0;
                                }
                        } else {
                                tteflag = 0;
                        }
                        if (tteflag && !(sfmmup->sfmmu_rtteflags & tteflag)) {
                                hatlockp = sfmmu_hat_enter(sfmmup);
                                sfmmup->sfmmu_rtteflags |= tteflag;
                                sfmmu_hat_exit(hatlockp);
                        }
                        hatlockp = sfmmu_hat_enter(sfmmup);

                        /*
                         * Preallocate 1/4 of ttecnt's in 8K TSB for >= 4M
                         * region to allow for large page allocation failure.
                         */
                        if (r_pgszc >= TTE4M) {
                                sfmmup->sfmmu_tsb0_4minflcnt +=
                                    r_size >> (TTE_PAGE_SHIFT(TTE8K) + 2);
                        }

                        /* update sfmmu_ttecnt with the shme rgn ttecnt */
                        rttecnt = r_size >> TTE_PAGE_SHIFT(r_pgszc);
                        atomic_add_long(&sfmmup->sfmmu_ttecnt[r_pgszc],
                            rttecnt);

                        if (text && r_pgszc >= TTE4M &&
                            (tteflag || ((disable_large_pages >> TTE4M) &
                            ((1 << (r_pgszc - TTE4M + 1)) - 1))) &&
                            !SFMMU_FLAGS_ISSET(sfmmup, HAT_4MTEXT_FLAG)) {
                                SFMMU_FLAGS_SET(sfmmup, HAT_4MTEXT_FLAG);
                        }

                        sfmmu_hat_exit(hatlockp);
                        /*
                         * On Panther we need to make sure TLB is programmed
                         * to accept 32M/256M pages.  Call
                         * sfmmu_check_page_sizes() now to make sure TLB is
                         * setup before making hmeregions visible to other
                         * threads.
                         */
                        sfmmu_check_page_sizes(sfmmup, 1);
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        SF_RGNMAP_ADD(sfmmup->sfmmu_hmeregion_map, rid);

                        /*
                         * if context is invalid tsb miss exception code will
                         * call sfmmu_check_page_sizes() and update tsbmiss
                         * area later.
                         */
                        kpreempt_disable();
                        if (myjoin &&
                            (sfmmup->sfmmu_ctxs[CPU_MMU_IDX(CPU)].cnum
                            != INVALID_CONTEXT)) {
                                struct tsbmiss *tsbmp;

                                tsbmp = &tsbmiss_area[CPU->cpu_id];
                                ASSERT(sfmmup == tsbmp->usfmmup);
                                BT_SET(tsbmp->shmermap, rid);
                                if (r_pgszc > TTE64K) {
                                        tsbmp->uhat_rtteflags |= tteflag;
                                }

                        }
                        kpreempt_enable();

                        sfmmu_hat_exit(hatlockp);
                        ASSERT((hat_region_cookie_t)((uint64_t)rid) !=
                            HAT_INVALID_REGION_COOKIE);
                } else {
                        hatlockp = sfmmu_hat_enter(sfmmup);
                        SF_RGNMAP_ADD(sfmmup->sfmmu_ismregion_map, rid);
                        sfmmu_hat_exit(hatlockp);
                }
                ASSERT(rid < maxids);

                if (r_type == SFMMU_REGION_ISM) {
                        sfmmu_find_scd(sfmmup);
                }
                return ((hat_region_cookie_t)((uint64_t)rid));
        }

        ASSERT(new_rgnp == NULL);

        if (*busyrgnsp >= maxids) {
                mutex_exit(&srdp->srd_mutex);
                return (HAT_INVALID_REGION_COOKIE);
        }

        ASSERT(MUTEX_HELD(&srdp->srd_mutex));
        if (*freelistp != NULL) {
                rgnp = *freelistp;
                *freelistp = rgnp->rgn_next;
                ASSERT(rgnp->rgn_id < *nextidp);
                ASSERT(rgnp->rgn_id < maxids);
                ASSERT(rgnp->rgn_flags & SFMMU_REGION_FREE);
                ASSERT((rgnp->rgn_flags & SFMMU_REGION_TYPE_MASK)
                    == r_type);
                ASSERT(rarrp[rgnp->rgn_id] == rgnp);
                ASSERT(rgnp->rgn_hmeflags == 0);
        } else {
                /*
                 * release local locks before memory allocation.
                 */
                mutex_exit(&srdp->srd_mutex);

                new_rgnp = kmem_cache_alloc(region_cache, KM_SLEEP);

                mutex_enter(&srdp->srd_mutex);
                for (rgnp = srdp->srd_rgnhash[rhash]; rgnp != NULL;
                    rgnp = rgnp->rgn_hash) {
                        if (rgnp->rgn_saddr == r_saddr &&
                            rgnp->rgn_size == r_size &&
                            rgnp->rgn_obj == r_obj &&
                            rgnp->rgn_objoff == r_objoff &&
                            rgnp->rgn_perm == r_perm &&
                            rgnp->rgn_pgszc == r_pgszc) {
                                break;
                        }
                }
                if (rgnp != NULL) {
                        goto rfound;
                }

                if (*nextidp >= maxids) {
                        mutex_exit(&srdp->srd_mutex);
                        goto fail;
                }
                rgnp = new_rgnp;
                new_rgnp = NULL;
                rgnp->rgn_id = (*nextidp)++;
                ASSERT(rgnp->rgn_id < maxids);
                ASSERT(rarrp[rgnp->rgn_id] == NULL);
                rarrp[rgnp->rgn_id] = rgnp;
        }

        ASSERT(rgnp->rgn_sfmmu_head == NULL);
        ASSERT(rgnp->rgn_hmeflags == 0);
#ifdef DEBUG
        for (i = 0; i < MMU_PAGE_SIZES; i++) {
                ASSERT(rgnp->rgn_ttecnt[i] == 0);
        }
#endif
        rgnp->rgn_saddr = r_saddr;
        rgnp->rgn_size = r_size;
        rgnp->rgn_obj = r_obj;
        rgnp->rgn_objoff = r_objoff;
        rgnp->rgn_perm = r_perm;
        rgnp->rgn_pgszc = r_pgszc;
        rgnp->rgn_flags = r_type;
        rgnp->rgn_refcnt = 0;
        rgnp->rgn_cb_function = r_cb_function;
        rgnp->rgn_hash = srdp->srd_rgnhash[rhash];
        srdp->srd_rgnhash[rhash] = rgnp;
        (*busyrgnsp)++;
        ASSERT(*busyrgnsp <= maxids);
        goto rfound;

fail:
        ASSERT(new_rgnp != NULL);
        kmem_cache_free(region_cache, new_rgnp);
        return (HAT_INVALID_REGION_COOKIE);
}

/*
 * This function implements the shared context functionality required
 * when detaching a segment from an address space. It must be called
 * from hat_unshare() for all D(ISM) segments and from segvn_unmap(),
 * for segments with a valid region_cookie.
 * It will also be called from all seg_vn routines which change a
 * segment's attributes such as segvn_setprot(), segvn_setpagesize(),
 * segvn_clrszc() & segvn_advise(), as well as in the case of COW fault
 * from segvn_fault().
 */
void
hat_leave_region(struct hat *sfmmup, hat_region_cookie_t rcookie, uint_t flags)
{
        sf_srd_t *srdp = sfmmup->sfmmu_srdp;
        sf_scd_t *scdp;
        uint_t rhash;
        uint_t rid = (uint_t)((uint64_t)rcookie);
        hatlock_t *hatlockp = NULL;
        sf_region_t *rgnp;
        sf_region_t **prev_rgnpp;
        sf_region_t *cur_rgnp;
        void *r_obj;
        int i;
        caddr_t r_saddr;
        caddr_t r_eaddr;
        size_t  r_size;
        uchar_t r_pgszc;
        uchar_t r_type = flags & HAT_REGION_TYPE_MASK;

        ASSERT(sfmmup != ksfmmup);
        ASSERT(srdp != NULL);
        ASSERT(srdp->srd_refcnt > 0);
        ASSERT(!(flags & ~HAT_REGION_TYPE_MASK));
        ASSERT(flags == HAT_REGION_TEXT || flags == HAT_REGION_ISM);
        ASSERT(!sfmmup->sfmmu_free || sfmmup->sfmmu_scdp == NULL);

        r_type = (r_type == HAT_REGION_ISM) ? SFMMU_REGION_ISM :
            SFMMU_REGION_HME;

        if (r_type == SFMMU_REGION_ISM) {
                ASSERT(SFMMU_IS_ISMRID_VALID(rid));
                ASSERT(rid < SFMMU_MAX_ISM_REGIONS);
                rgnp = srdp->srd_ismrgnp[rid];
        } else {
                ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                rgnp = srdp->srd_hmergnp[rid];
        }
        ASSERT(rgnp != NULL);
        ASSERT(rgnp->rgn_id == rid);
        ASSERT((rgnp->rgn_flags & SFMMU_REGION_TYPE_MASK) == r_type);
        ASSERT(!(rgnp->rgn_flags & SFMMU_REGION_FREE));
        ASSERT(AS_LOCK_HELD(sfmmup->sfmmu_as));

        if (sfmmup->sfmmu_free) {
                ulong_t rttecnt;
                r_pgszc = rgnp->rgn_pgszc;
                r_size = rgnp->rgn_size;

                ASSERT(sfmmup->sfmmu_scdp == NULL);
                if (r_type == SFMMU_REGION_ISM) {
                        SF_RGNMAP_DEL(sfmmup->sfmmu_ismregion_map, rid);
                } else {
                        /* update shme rgns ttecnt in sfmmu_ttecnt */
                        rttecnt = r_size >> TTE_PAGE_SHIFT(r_pgszc);
                        ASSERT(sfmmup->sfmmu_ttecnt[r_pgszc] >= rttecnt);

                        atomic_add_long(&sfmmup->sfmmu_ttecnt[r_pgszc],
                            -rttecnt);

                        SF_RGNMAP_DEL(sfmmup->sfmmu_hmeregion_map, rid);
                }
        } else if (r_type == SFMMU_REGION_ISM) {
                hatlockp = sfmmu_hat_enter(sfmmup);
                ASSERT(rid < srdp->srd_next_ismrid);
                SF_RGNMAP_DEL(sfmmup->sfmmu_ismregion_map, rid);
                scdp = sfmmup->sfmmu_scdp;
                if (scdp != NULL &&
                    SF_RGNMAP_TEST(scdp->scd_ismregion_map, rid)) {
                        sfmmu_leave_scd(sfmmup, r_type);
                        ASSERT(sfmmu_hat_lock_held(sfmmup));
                }
                sfmmu_hat_exit(hatlockp);
        } else {
                ulong_t rttecnt;
                r_pgszc = rgnp->rgn_pgszc;
                r_saddr = rgnp->rgn_saddr;
                r_size = rgnp->rgn_size;
                r_eaddr = r_saddr + r_size;

                ASSERT(r_type == SFMMU_REGION_HME);
                hatlockp = sfmmu_hat_enter(sfmmup);
                ASSERT(rid < srdp->srd_next_hmerid);
                SF_RGNMAP_DEL(sfmmup->sfmmu_hmeregion_map, rid);

                /*
                 * If region is part of an SCD call sfmmu_leave_scd().
                 * Otherwise if process is not exiting and has valid context
                 * just drop the context on the floor to lose stale TLB
                 * entries and force the update of tsb miss area to reflect
                 * the new region map. After that clean our TSB entries.
                 */
                scdp = sfmmup->sfmmu_scdp;
                if (scdp != NULL &&
                    SF_RGNMAP_TEST(scdp->scd_hmeregion_map, rid)) {
                        sfmmu_leave_scd(sfmmup, r_type);
                        ASSERT(sfmmu_hat_lock_held(sfmmup));
                }
                sfmmu_invalidate_ctx(sfmmup);

                i = TTE8K;
                while (i < mmu_page_sizes) {
                        if (rgnp->rgn_ttecnt[i] != 0) {
                                sfmmu_unload_tsb_range(sfmmup, r_saddr,
                                    r_eaddr, i);
                                if (i < TTE4M) {
                                        i = TTE4M;
                                        continue;
                                } else {
                                        break;
                                }
                        }
                        i++;
                }
                /* Remove the preallocated 1/4 8k ttecnt for 4M regions. */
                if (r_pgszc >= TTE4M) {
                        rttecnt = r_size >> (TTE_PAGE_SHIFT(TTE8K) + 2);
                        ASSERT(sfmmup->sfmmu_tsb0_4minflcnt >=
                            rttecnt);
                        sfmmup->sfmmu_tsb0_4minflcnt -= rttecnt;
                }

                /* update shme rgns ttecnt in sfmmu_ttecnt */
                rttecnt = r_size >> TTE_PAGE_SHIFT(r_pgszc);
                ASSERT(sfmmup->sfmmu_ttecnt[r_pgszc] >= rttecnt);
                atomic_add_long(&sfmmup->sfmmu_ttecnt[r_pgszc], -rttecnt);

                sfmmu_hat_exit(hatlockp);
                if (scdp != NULL && sfmmup->sfmmu_scdp == NULL) {
                        /* sfmmup left the scd, grow private tsb */
                        sfmmu_check_page_sizes(sfmmup, 1);
                } else {
                        sfmmu_check_page_sizes(sfmmup, 0);
                }
        }

        if (r_type == SFMMU_REGION_HME) {
                sfmmu_unlink_from_hmeregion(sfmmup, rgnp);
        }

        r_obj = rgnp->rgn_obj;
        if (atomic_dec_32_nv((volatile uint_t *)&rgnp->rgn_refcnt)) {
                return;
        }

        /*
         * looks like nobody uses this region anymore. Free it.
         */
        rhash = RGN_HASH_FUNCTION(r_obj);
        mutex_enter(&srdp->srd_mutex);
        for (prev_rgnpp = &srdp->srd_rgnhash[rhash];
            (cur_rgnp = *prev_rgnpp) != NULL;
            prev_rgnpp = &cur_rgnp->rgn_hash) {
                if (cur_rgnp == rgnp && cur_rgnp->rgn_refcnt == 0) {
                        break;
                }
        }

        if (cur_rgnp == NULL) {
                mutex_exit(&srdp->srd_mutex);
                return;
        }

        ASSERT((rgnp->rgn_flags & SFMMU_REGION_TYPE_MASK) == r_type);
        *prev_rgnpp = rgnp->rgn_hash;
        if (r_type == SFMMU_REGION_ISM) {
                rgnp->rgn_flags |= SFMMU_REGION_FREE;
                ASSERT(rid < srdp->srd_next_ismrid);
                rgnp->rgn_next = srdp->srd_ismrgnfree;
                srdp->srd_ismrgnfree = rgnp;
                ASSERT(srdp->srd_ismbusyrgns > 0);
                srdp->srd_ismbusyrgns--;
                mutex_exit(&srdp->srd_mutex);
                return;
        }
        mutex_exit(&srdp->srd_mutex);

        /*
         * Destroy region's hmeblks.
         */
        sfmmu_unload_hmeregion(srdp, rgnp);

        rgnp->rgn_hmeflags = 0;

        ASSERT(rgnp->rgn_sfmmu_head == NULL);
        ASSERT(rgnp->rgn_id == rid);
        for (i = 0; i < MMU_PAGE_SIZES; i++) {
                rgnp->rgn_ttecnt[i] = 0;
        }
        rgnp->rgn_flags |= SFMMU_REGION_FREE;
        mutex_enter(&srdp->srd_mutex);
        ASSERT(rid < srdp->srd_next_hmerid);
        rgnp->rgn_next = srdp->srd_hmergnfree;
        srdp->srd_hmergnfree = rgnp;
        ASSERT(srdp->srd_hmebusyrgns > 0);
        srdp->srd_hmebusyrgns--;
        mutex_exit(&srdp->srd_mutex);
}

/*
 * For now only called for hmeblk regions and not for ISM regions.
 */
void
hat_dup_region(struct hat *sfmmup, hat_region_cookie_t rcookie)
{
        sf_srd_t *srdp = sfmmup->sfmmu_srdp;
        uint_t rid = (uint_t)((uint64_t)rcookie);
        sf_region_t *rgnp;
        sf_rgn_link_t *rlink;
        sf_rgn_link_t *hrlink;
        ulong_t rttecnt;

        ASSERT(sfmmup != ksfmmup);
        ASSERT(srdp != NULL);
        ASSERT(srdp->srd_refcnt > 0);

        ASSERT(rid < srdp->srd_next_hmerid);
        ASSERT(SFMMU_IS_SHMERID_VALID(rid));
        ASSERT(rid < SFMMU_MAX_HME_REGIONS);

        rgnp = srdp->srd_hmergnp[rid];
        ASSERT(rgnp->rgn_refcnt > 0);
        ASSERT(rgnp->rgn_id == rid);
        ASSERT((rgnp->rgn_flags & SFMMU_REGION_TYPE_MASK) == SFMMU_REGION_HME);
        ASSERT(!(rgnp->rgn_flags & SFMMU_REGION_FREE));

        atomic_inc_32((volatile uint_t *)&rgnp->rgn_refcnt);

        /* LINTED: constant in conditional context */
        SFMMU_HMERID2RLINKP(sfmmup, rid, rlink, 1, 0);
        ASSERT(rlink != NULL);
        mutex_enter(&rgnp->rgn_mutex);
        ASSERT(rgnp->rgn_sfmmu_head != NULL);
        /* LINTED: constant in conditional context */
        SFMMU_HMERID2RLINKP(rgnp->rgn_sfmmu_head, rid, hrlink, 0, 0);
        ASSERT(hrlink != NULL);
        ASSERT(hrlink->prev == NULL);
        rlink->next = rgnp->rgn_sfmmu_head;
        rlink->prev = NULL;
        hrlink->prev = sfmmup;
        /*
         * make sure rlink's next field is correct
         * before making this link visible.
         */
        membar_stst();
        rgnp->rgn_sfmmu_head = sfmmup;
        mutex_exit(&rgnp->rgn_mutex);

        /* update sfmmu_ttecnt with the shme rgn ttecnt */
        rttecnt = rgnp->rgn_size >> TTE_PAGE_SHIFT(rgnp->rgn_pgszc);
        atomic_add_long(&sfmmup->sfmmu_ttecnt[rgnp->rgn_pgszc], rttecnt);
        /* update tsb0 inflation count */
        if (rgnp->rgn_pgszc >= TTE4M) {
                sfmmup->sfmmu_tsb0_4minflcnt +=
                    rgnp->rgn_size >> (TTE_PAGE_SHIFT(TTE8K) + 2);
        }
        /*
         * Update regionid bitmask without hat lock since no other thread
         * can update this region bitmask right now.
         */
        SF_RGNMAP_ADD(sfmmup->sfmmu_hmeregion_map, rid);
}

/* ARGSUSED */
static int
sfmmu_rgncache_constructor(void *buf, void *cdrarg, int kmflags)
{
        sf_region_t *rgnp = (sf_region_t *)buf;
        bzero(buf, sizeof (*rgnp));

        mutex_init(&rgnp->rgn_mutex, NULL, MUTEX_DEFAULT, NULL);

        return (0);
}

/* ARGSUSED */
static void
sfmmu_rgncache_destructor(void *buf, void *cdrarg)
{
        sf_region_t *rgnp = (sf_region_t *)buf;
        mutex_destroy(&rgnp->rgn_mutex);
}

static int
sfrgnmap_isnull(sf_region_map_t *map)
{
        int i;

        for (i = 0; i < SFMMU_RGNMAP_WORDS; i++) {
                if (map->bitmap[i] != 0) {
                        return (0);
                }
        }
        return (1);
}

static int
sfhmergnmap_isnull(sf_hmeregion_map_t *map)
{
        int i;

        for (i = 0; i < SFMMU_HMERGNMAP_WORDS; i++) {
                if (map->bitmap[i] != 0) {
                        return (0);
                }
        }
        return (1);
}

#ifdef DEBUG
static void
check_scd_sfmmu_list(sfmmu_t **headp, sfmmu_t *sfmmup, int onlist)
{
        sfmmu_t *sp;
        sf_srd_t *srdp = sfmmup->sfmmu_srdp;

        for (sp = *headp; sp != NULL; sp = sp->sfmmu_scd_link.next) {
                ASSERT(srdp == sp->sfmmu_srdp);
                if (sp == sfmmup) {
                        if (onlist) {
                                return;
                        } else {
                                panic("shctx: sfmmu 0x%p found on scd"
                                    "list 0x%p", (void *)sfmmup,
                                    (void *)*headp);
                        }
                }
        }
        if (onlist) {
                panic("shctx: sfmmu 0x%p not found on scd list 0x%p",
                    (void *)sfmmup, (void *)*headp);
        } else {
                return;
        }
}
#else /* DEBUG */
#define check_scd_sfmmu_list(headp, sfmmup, onlist)
#endif /* DEBUG */

/*
 * Removes an sfmmu from the SCD sfmmu list.
 */
static void
sfmmu_from_scd_list(sfmmu_t **headp, sfmmu_t *sfmmup)
{
        ASSERT(sfmmup->sfmmu_srdp != NULL);
        check_scd_sfmmu_list(headp, sfmmup, 1);
        if (sfmmup->sfmmu_scd_link.prev != NULL) {
                ASSERT(*headp != sfmmup);
                sfmmup->sfmmu_scd_link.prev->sfmmu_scd_link.next =
                    sfmmup->sfmmu_scd_link.next;
        } else {
                ASSERT(*headp == sfmmup);
                *headp = sfmmup->sfmmu_scd_link.next;
        }
        if (sfmmup->sfmmu_scd_link.next != NULL) {
                sfmmup->sfmmu_scd_link.next->sfmmu_scd_link.prev =
                    sfmmup->sfmmu_scd_link.prev;
        }
}


/*
 * Adds an sfmmu to the start of the queue.
 */
static void
sfmmu_to_scd_list(sfmmu_t **headp, sfmmu_t *sfmmup)
{
        check_scd_sfmmu_list(headp, sfmmup, 0);
        sfmmup->sfmmu_scd_link.prev = NULL;
        sfmmup->sfmmu_scd_link.next = *headp;
        if (*headp != NULL)
                (*headp)->sfmmu_scd_link.prev = sfmmup;
        *headp = sfmmup;
}

/*
 * Remove an scd from the start of the queue.
 */
static void
sfmmu_remove_scd(sf_scd_t **headp, sf_scd_t *scdp)
{
        if (scdp->scd_prev != NULL) {
                ASSERT(*headp != scdp);
                scdp->scd_prev->scd_next = scdp->scd_next;
        } else {
                ASSERT(*headp == scdp);
                *headp = scdp->scd_next;
        }

        if (scdp->scd_next != NULL) {
                scdp->scd_next->scd_prev = scdp->scd_prev;
        }
}

/*
 * Add an scd to the start of the queue.
 */
static void
sfmmu_add_scd(sf_scd_t **headp, sf_scd_t *scdp)
{
        scdp->scd_prev = NULL;
        scdp->scd_next = *headp;
        if (*headp != NULL) {
                (*headp)->scd_prev = scdp;
        }
        *headp = scdp;
}

static int
sfmmu_alloc_scd_tsbs(sf_srd_t *srdp, sf_scd_t *scdp)
{
        uint_t rid;
        uint_t i;
        uint_t j;
        ulong_t w;
        sf_region_t *rgnp;
        ulong_t tte8k_cnt = 0;
        ulong_t tte4m_cnt = 0;
        uint_t tsb_szc;
        sfmmu_t *scsfmmup = scdp->scd_sfmmup;
        sfmmu_t *ism_hatid;
        struct tsb_info *newtsb;
        int szc;

        ASSERT(srdp != NULL);

        for (i = 0; i < SFMMU_RGNMAP_WORDS; i++) {
                if ((w = scdp->scd_region_map.bitmap[i]) == 0) {
                        continue;
                }
                j = 0;
                while (w) {
                        if (!(w & 0x1)) {
                                j++;
                                w >>= 1;
                                continue;
                        }
                        rid = (i << BT_ULSHIFT) | j;
                        j++;
                        w >>= 1;

                        if (rid < SFMMU_MAX_HME_REGIONS) {
                                rgnp = srdp->srd_hmergnp[rid];
                                ASSERT(rgnp->rgn_id == rid);
                                ASSERT(rgnp->rgn_refcnt > 0);

                                if (rgnp->rgn_pgszc < TTE4M) {
                                        tte8k_cnt += rgnp->rgn_size >>
                                            TTE_PAGE_SHIFT(TTE8K);
                                } else {
                                        ASSERT(rgnp->rgn_pgszc >= TTE4M);
                                        tte4m_cnt += rgnp->rgn_size >>
                                            TTE_PAGE_SHIFT(TTE4M);
                                        /*
                                         * Inflate SCD tsb0 by preallocating
                                         * 1/4 8k ttecnt for 4M regions to
                                         * allow for lgpg alloc failure.
                                         */
                                        tte8k_cnt += rgnp->rgn_size >>
                                            (TTE_PAGE_SHIFT(TTE8K) + 2);
                                }
                        } else {
                                rid -= SFMMU_MAX_HME_REGIONS;
                                rgnp = srdp->srd_ismrgnp[rid];
                                ASSERT(rgnp->rgn_id == rid);
                                ASSERT(rgnp->rgn_refcnt > 0);

                                ism_hatid = (sfmmu_t *)rgnp->rgn_obj;
                                ASSERT(ism_hatid->sfmmu_ismhat);

                                for (szc = 0; szc < TTE4M; szc++) {
                                        tte8k_cnt +=
                                            ism_hatid->sfmmu_ttecnt[szc] <<
                                            TTE_BSZS_SHIFT(szc);
                                }

                                ASSERT(rgnp->rgn_pgszc >= TTE4M);
                                if (rgnp->rgn_pgszc >= TTE4M) {
                                        tte4m_cnt += rgnp->rgn_size >>
                                            TTE_PAGE_SHIFT(TTE4M);
                                }
                        }
                }
        }

        tsb_szc = SELECT_TSB_SIZECODE(tte8k_cnt);

        /* Allocate both the SCD TSBs here. */
        if (sfmmu_tsbinfo_alloc(&scsfmmup->sfmmu_tsb,
            tsb_szc, TSB8K|TSB64K|TSB512K, TSB_ALLOC, scsfmmup) &&
            (tsb_szc <= TSB_4M_SZCODE ||
            sfmmu_tsbinfo_alloc(&scsfmmup->sfmmu_tsb,
            TSB_4M_SZCODE, TSB8K|TSB64K|TSB512K,
            TSB_ALLOC, scsfmmup))) {

                SFMMU_STAT(sf_scd_1sttsb_allocfail);
                return (TSB_ALLOCFAIL);
        } else {
                scsfmmup->sfmmu_tsb->tsb_flags |= TSB_SHAREDCTX;

                if (tte4m_cnt) {
                        tsb_szc = SELECT_TSB_SIZECODE(tte4m_cnt);
                        if (sfmmu_tsbinfo_alloc(&newtsb, tsb_szc,
                            TSB4M|TSB32M|TSB256M, TSB_ALLOC, scsfmmup) &&
                            (tsb_szc <= TSB_4M_SZCODE ||
                            sfmmu_tsbinfo_alloc(&newtsb, TSB_4M_SZCODE,
                            TSB4M|TSB32M|TSB256M,
                            TSB_ALLOC, scsfmmup))) {
                                /*
                                 * If we fail to allocate the 2nd shared tsb,
                                 * just free the 1st tsb, return failure.
                                 */
                                sfmmu_tsbinfo_free(scsfmmup->sfmmu_tsb);
                                SFMMU_STAT(sf_scd_2ndtsb_allocfail);
                                return (TSB_ALLOCFAIL);
                        } else {
                                ASSERT(scsfmmup->sfmmu_tsb->tsb_next == NULL);
                                newtsb->tsb_flags |= TSB_SHAREDCTX;
                                scsfmmup->sfmmu_tsb->tsb_next = newtsb;
                                SFMMU_STAT(sf_scd_2ndtsb_alloc);
                        }
                }
                SFMMU_STAT(sf_scd_1sttsb_alloc);
        }
        return (TSB_SUCCESS);
}

static void
sfmmu_free_scd_tsbs(sfmmu_t *scd_sfmmu)
{
        while (scd_sfmmu->sfmmu_tsb != NULL) {
                struct tsb_info *next = scd_sfmmu->sfmmu_tsb->tsb_next;
                sfmmu_tsbinfo_free(scd_sfmmu->sfmmu_tsb);
                scd_sfmmu->sfmmu_tsb = next;
        }
}

/*
 * Link the sfmmu onto the hme region list.
 */
void
sfmmu_link_to_hmeregion(sfmmu_t *sfmmup, sf_region_t *rgnp)
{
        uint_t rid;
        sf_rgn_link_t *rlink;
        sfmmu_t *head;
        sf_rgn_link_t *hrlink;

        rid = rgnp->rgn_id;
        ASSERT(SFMMU_IS_SHMERID_VALID(rid));

        /* LINTED: constant in conditional context */
        SFMMU_HMERID2RLINKP(sfmmup, rid, rlink, 1, 1);
        ASSERT(rlink != NULL);
        mutex_enter(&rgnp->rgn_mutex);
        if ((head = rgnp->rgn_sfmmu_head) == NULL) {
                rlink->next = NULL;
                rlink->prev = NULL;
                /*
                 * make sure rlink's next field is NULL
                 * before making this link visible.
                 */
                membar_stst();
                rgnp->rgn_sfmmu_head = sfmmup;
        } else {
                /* LINTED: constant in conditional context */
                SFMMU_HMERID2RLINKP(head, rid, hrlink, 0, 0);
                ASSERT(hrlink != NULL);
                ASSERT(hrlink->prev == NULL);
                rlink->next = head;
                rlink->prev = NULL;
                hrlink->prev = sfmmup;
                /*
                 * make sure rlink's next field is correct
                 * before making this link visible.
                 */
                membar_stst();
                rgnp->rgn_sfmmu_head = sfmmup;
        }
        mutex_exit(&rgnp->rgn_mutex);
}

/*
 * Unlink the sfmmu from the hme region list.
 */
void
sfmmu_unlink_from_hmeregion(sfmmu_t *sfmmup, sf_region_t *rgnp)
{
        uint_t rid;
        sf_rgn_link_t *rlink;

        rid = rgnp->rgn_id;
        ASSERT(SFMMU_IS_SHMERID_VALID(rid));

        /* LINTED: constant in conditional context */
        SFMMU_HMERID2RLINKP(sfmmup, rid, rlink, 0, 0);
        ASSERT(rlink != NULL);
        mutex_enter(&rgnp->rgn_mutex);
        if (rgnp->rgn_sfmmu_head == sfmmup) {
                sfmmu_t *next = rlink->next;
                rgnp->rgn_sfmmu_head = next;
                /*
                 * if we are stopped by xc_attention() after this
                 * point the forward link walking in
                 * sfmmu_rgntlb_demap() will work correctly since the
                 * head correctly points to the next element.
                 */
                membar_stst();
                rlink->next = NULL;
                ASSERT(rlink->prev == NULL);
                if (next != NULL) {
                        sf_rgn_link_t *nrlink;
                        /* LINTED: constant in conditional context */
                        SFMMU_HMERID2RLINKP(next, rid, nrlink, 0, 0);
                        ASSERT(nrlink != NULL);
                        ASSERT(nrlink->prev == sfmmup);
                        nrlink->prev = NULL;
                }
        } else {
                sfmmu_t *next = rlink->next;
                sfmmu_t *prev = rlink->prev;
                sf_rgn_link_t *prlink;

                ASSERT(prev != NULL);
                /* LINTED: constant in conditional context */
                SFMMU_HMERID2RLINKP(prev, rid, prlink, 0, 0);
                ASSERT(prlink != NULL);
                ASSERT(prlink->next == sfmmup);
                prlink->next = next;
                /*
                 * if we are stopped by xc_attention()
                 * after this point the forward link walking
                 * will work correctly since the prev element
                 * correctly points to the next element.
                 */
                membar_stst();
                rlink->next = NULL;
                rlink->prev = NULL;
                if (next != NULL) {
                        sf_rgn_link_t *nrlink;
                        /* LINTED: constant in conditional context */
                        SFMMU_HMERID2RLINKP(next, rid, nrlink, 0, 0);
                        ASSERT(nrlink != NULL);
                        ASSERT(nrlink->prev == sfmmup);
                        nrlink->prev = prev;
                }
        }
        mutex_exit(&rgnp->rgn_mutex);
}

/*
 * Link scd sfmmu onto ism or hme region list for each region in the
 * scd region map.
 */
void
sfmmu_link_scd_to_regions(sf_srd_t *srdp, sf_scd_t *scdp)
{
        uint_t rid;
        uint_t i;
        uint_t j;
        ulong_t w;
        sf_region_t *rgnp;
        sfmmu_t *scsfmmup;

        scsfmmup = scdp->scd_sfmmup;
        ASSERT(scsfmmup->sfmmu_scdhat);
        for (i = 0; i < SFMMU_RGNMAP_WORDS; i++) {
                if ((w = scdp->scd_region_map.bitmap[i]) == 0) {
                        continue;
                }
                j = 0;
                while (w) {
                        if (!(w & 0x1)) {
                                j++;
                                w >>= 1;
                                continue;
                        }
                        rid = (i << BT_ULSHIFT) | j;
                        j++;
                        w >>= 1;

                        if (rid < SFMMU_MAX_HME_REGIONS) {
                                rgnp = srdp->srd_hmergnp[rid];
                                ASSERT(rgnp->rgn_id == rid);
                                ASSERT(rgnp->rgn_refcnt > 0);
                                sfmmu_link_to_hmeregion(scsfmmup, rgnp);
                        } else {
                                sfmmu_t *ism_hatid = NULL;
                                ism_ment_t *ism_ment;
                                rid -= SFMMU_MAX_HME_REGIONS;
                                rgnp = srdp->srd_ismrgnp[rid];
                                ASSERT(rgnp->rgn_id == rid);
                                ASSERT(rgnp->rgn_refcnt > 0);

                                ism_hatid = (sfmmu_t *)rgnp->rgn_obj;
                                ASSERT(ism_hatid->sfmmu_ismhat);
                                ism_ment = &scdp->scd_ism_links[rid];
                                ism_ment->iment_hat = scsfmmup;
                                ism_ment->iment_base_va = rgnp->rgn_saddr;
                                mutex_enter(&ism_mlist_lock);
                                iment_add(ism_ment, ism_hatid);
                                mutex_exit(&ism_mlist_lock);

                        }
                }
        }
}
/*
 * Unlink scd sfmmu from ism or hme region list for each region in the
 * scd region map.
 */
void
sfmmu_unlink_scd_from_regions(sf_srd_t *srdp, sf_scd_t *scdp)
{
        uint_t rid;
        uint_t i;
        uint_t j;
        ulong_t w;
        sf_region_t *rgnp;
        sfmmu_t *scsfmmup;

        scsfmmup = scdp->scd_sfmmup;
        for (i = 0; i < SFMMU_RGNMAP_WORDS; i++) {
                if ((w = scdp->scd_region_map.bitmap[i]) == 0) {
                        continue;
                }
                j = 0;
                while (w) {
                        if (!(w & 0x1)) {
                                j++;
                                w >>= 1;
                                continue;
                        }
                        rid = (i << BT_ULSHIFT) | j;
                        j++;
                        w >>= 1;

                        if (rid < SFMMU_MAX_HME_REGIONS) {
                                rgnp = srdp->srd_hmergnp[rid];
                                ASSERT(rgnp->rgn_id == rid);
                                ASSERT(rgnp->rgn_refcnt > 0);
                                sfmmu_unlink_from_hmeregion(scsfmmup,
                                    rgnp);

                        } else {
                                sfmmu_t *ism_hatid = NULL;
                                ism_ment_t *ism_ment;
                                rid -= SFMMU_MAX_HME_REGIONS;
                                rgnp = srdp->srd_ismrgnp[rid];
                                ASSERT(rgnp->rgn_id == rid);
                                ASSERT(rgnp->rgn_refcnt > 0);

                                ism_hatid = (sfmmu_t *)rgnp->rgn_obj;
                                ASSERT(ism_hatid->sfmmu_ismhat);
                                ism_ment = &scdp->scd_ism_links[rid];
                                ASSERT(ism_ment->iment_hat == scdp->scd_sfmmup);
                                ASSERT(ism_ment->iment_base_va ==
                                    rgnp->rgn_saddr);
                                mutex_enter(&ism_mlist_lock);
                                iment_sub(ism_ment, ism_hatid);
                                mutex_exit(&ism_mlist_lock);

                        }
                }
        }
}
/*
 * Allocates and initialises a new SCD structure, this is called with
 * the srd_scd_mutex held and returns with the reference count
 * initialised to 1.
 */
static sf_scd_t *
sfmmu_alloc_scd(sf_srd_t *srdp, sf_region_map_t *new_map)
{
        sf_scd_t *new_scdp;
        sfmmu_t *scsfmmup;
        int i;

        ASSERT(MUTEX_HELD(&srdp->srd_scd_mutex));
        new_scdp = kmem_cache_alloc(scd_cache, KM_SLEEP);

        scsfmmup = kmem_cache_alloc(sfmmuid_cache, KM_SLEEP);
        new_scdp->scd_sfmmup = scsfmmup;
        scsfmmup->sfmmu_srdp = srdp;
        scsfmmup->sfmmu_scdp = new_scdp;
        scsfmmup->sfmmu_tsb0_4minflcnt = 0;
        scsfmmup->sfmmu_scdhat = 1;
        CPUSET_ALL(scsfmmup->sfmmu_cpusran);
        bzero(scsfmmup->sfmmu_hmeregion_links, SFMMU_L1_HMERLINKS_SIZE);

        ASSERT(max_mmu_ctxdoms > 0);
        for (i = 0; i < max_mmu_ctxdoms; i++) {
                scsfmmup->sfmmu_ctxs[i].cnum = INVALID_CONTEXT;
                scsfmmup->sfmmu_ctxs[i].gnum = 0;
        }

        for (i = 0; i < MMU_PAGE_SIZES; i++) {
                new_scdp->scd_rttecnt[i] = 0;
        }

        new_scdp->scd_region_map = *new_map;
        new_scdp->scd_refcnt = 1;
        if (sfmmu_alloc_scd_tsbs(srdp, new_scdp) != TSB_SUCCESS) {
                kmem_cache_free(scd_cache, new_scdp);
                kmem_cache_free(sfmmuid_cache, scsfmmup);
                return (NULL);
        }
        if (&mmu_init_scd) {
                mmu_init_scd(new_scdp);
        }
        return (new_scdp);
}

/*
 * The first phase of a process joining an SCD. The hat structure is
 * linked to the SCD queue and then the HAT_JOIN_SCD sfmmu flag is set
 * and a cross-call with context invalidation is used to cause the
 * remaining work to be carried out in the sfmmu_tsbmiss_exception()
 * routine.
 */
static void
sfmmu_join_scd(sf_scd_t *scdp, sfmmu_t *sfmmup)
{
        hatlock_t *hatlockp;
        sf_srd_t *srdp = sfmmup->sfmmu_srdp;
        int i;
        sf_scd_t *old_scdp;

        ASSERT(srdp != NULL);
        ASSERT(scdp != NULL);
        ASSERT(scdp->scd_refcnt > 0);
        ASSERT(AS_WRITE_HELD(sfmmup->sfmmu_as));

        if ((old_scdp = sfmmup->sfmmu_scdp) != NULL) {
                ASSERT(old_scdp != scdp);

                mutex_enter(&old_scdp->scd_mutex);
                sfmmu_from_scd_list(&old_scdp->scd_sf_list, sfmmup);
                mutex_exit(&old_scdp->scd_mutex);
                /*
                 * sfmmup leaves the old scd. Update sfmmu_ttecnt to
                 * include the shme rgn ttecnt for rgns that
                 * were in the old SCD
                 */
                for (i = 0; i < mmu_page_sizes; i++) {
                        ASSERT(sfmmup->sfmmu_scdrttecnt[i] ==
                            old_scdp->scd_rttecnt[i]);
                        atomic_add_long(&sfmmup->sfmmu_ttecnt[i],
                            sfmmup->sfmmu_scdrttecnt[i]);
                }
        }

        /*
         * Move sfmmu to the scd lists.
         */
        mutex_enter(&scdp->scd_mutex);
        sfmmu_to_scd_list(&scdp->scd_sf_list, sfmmup);
        mutex_exit(&scdp->scd_mutex);
        SF_SCD_INCR_REF(scdp);

        hatlockp = sfmmu_hat_enter(sfmmup);
        /*
         * For a multi-thread process, we must stop
         * all the other threads before joining the scd.
         */

        SFMMU_FLAGS_SET(sfmmup, HAT_JOIN_SCD);

        sfmmu_invalidate_ctx(sfmmup);
        sfmmup->sfmmu_scdp = scdp;

        /*
         * Copy scd_rttecnt into sfmmup's sfmmu_scdrttecnt, and update
         * sfmmu_ttecnt to not include the rgn ttecnt just joined in SCD.
         */
        for (i = 0; i < mmu_page_sizes; i++) {
                sfmmup->sfmmu_scdrttecnt[i] = scdp->scd_rttecnt[i];
                ASSERT(sfmmup->sfmmu_ttecnt[i] >= scdp->scd_rttecnt[i]);
                atomic_add_long(&sfmmup->sfmmu_ttecnt[i],
                    -sfmmup->sfmmu_scdrttecnt[i]);
        }
        /* update tsb0 inflation count */
        if (old_scdp != NULL) {
                sfmmup->sfmmu_tsb0_4minflcnt +=
                    old_scdp->scd_sfmmup->sfmmu_tsb0_4minflcnt;
        }
        ASSERT(sfmmup->sfmmu_tsb0_4minflcnt >=
            scdp->scd_sfmmup->sfmmu_tsb0_4minflcnt);
        sfmmup->sfmmu_tsb0_4minflcnt -= scdp->scd_sfmmup->sfmmu_tsb0_4minflcnt;

        sfmmu_hat_exit(hatlockp);

        if (old_scdp != NULL) {
                SF_SCD_DECR_REF(srdp, old_scdp);
        }

}

/*
 * This routine is called by a process to become part of an SCD. It is called
 * from sfmmu_tsbmiss_exception() once most of the initial work has been
 * done by sfmmu_join_scd(). This routine must not drop the hat lock.
 */
static void
sfmmu_finish_join_scd(sfmmu_t *sfmmup)
{
        struct tsb_info *tsbinfop;

        ASSERT(sfmmu_hat_lock_held(sfmmup));
        ASSERT(sfmmup->sfmmu_scdp != NULL);
        ASSERT(SFMMU_FLAGS_ISSET(sfmmup, HAT_JOIN_SCD));
        ASSERT(!SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY));
        ASSERT(SFMMU_FLAGS_ISSET(sfmmup, HAT_ALLCTX_INVALID));

        for (tsbinfop = sfmmup->sfmmu_tsb; tsbinfop != NULL;
            tsbinfop = tsbinfop->tsb_next) {
                if (tsbinfop->tsb_flags & TSB_SWAPPED) {
                        continue;
                }
                ASSERT(!(tsbinfop->tsb_flags & TSB_RELOC_FLAG));

                sfmmu_inv_tsb(tsbinfop->tsb_va,
                    TSB_BYTES(tsbinfop->tsb_szc));
        }

        /* Set HAT_CTX1_FLAG for all SCD ISMs */
        sfmmu_ism_hatflags(sfmmup, 1);

        SFMMU_STAT(sf_join_scd);
}

/*
 * This routine is called in order to check if there is an SCD which matches
 * the process's region map if not then a new SCD may be created.
 */
static void
sfmmu_find_scd(sfmmu_t *sfmmup)
{
        sf_srd_t *srdp = sfmmup->sfmmu_srdp;
        sf_scd_t *scdp, *new_scdp;
        int ret;

        ASSERT(srdp != NULL);
        ASSERT(AS_WRITE_HELD(sfmmup->sfmmu_as));

        mutex_enter(&srdp->srd_scd_mutex);
        for (scdp = srdp->srd_scdp; scdp != NULL;
            scdp = scdp->scd_next) {
                SF_RGNMAP_EQUAL(&scdp->scd_region_map,
                    &sfmmup->sfmmu_region_map, ret);
                if (ret == 1) {
                        SF_SCD_INCR_REF(scdp);
                        mutex_exit(&srdp->srd_scd_mutex);
                        sfmmu_join_scd(scdp, sfmmup);
                        ASSERT(scdp->scd_refcnt >= 2);
                        atomic_dec_32((volatile uint32_t *)&scdp->scd_refcnt);
                        return;
                } else {
                        /*
                         * If the sfmmu region map is a subset of the scd
                         * region map, then the assumption is that this process
                         * will continue attaching to ISM segments until the
                         * region maps are equal.
                         */
                        SF_RGNMAP_IS_SUBSET(&scdp->scd_region_map,
                            &sfmmup->sfmmu_region_map, ret);
                        if (ret == 1) {
                                mutex_exit(&srdp->srd_scd_mutex);
                                return;
                        }
                }
        }

        ASSERT(scdp == NULL);
        /*
         * No matching SCD has been found, create a new one.
         */
        if ((new_scdp = sfmmu_alloc_scd(srdp, &sfmmup->sfmmu_region_map)) ==
            NULL) {
                mutex_exit(&srdp->srd_scd_mutex);
                return;
        }

        /*
         * sfmmu_alloc_scd() returns with a ref count of 1 on the scd.
         */

        /* Set scd_rttecnt for shme rgns in SCD */
        sfmmu_set_scd_rttecnt(srdp, new_scdp);

        /*
         * Link scd onto srd_scdp list and scd sfmmu onto region/iment lists.
         */
        sfmmu_link_scd_to_regions(srdp, new_scdp);
        sfmmu_add_scd(&srdp->srd_scdp, new_scdp);
        SFMMU_STAT_ADD(sf_create_scd, 1);

        mutex_exit(&srdp->srd_scd_mutex);
        sfmmu_join_scd(new_scdp, sfmmup);
        ASSERT(new_scdp->scd_refcnt >= 2);
        atomic_dec_32((volatile uint32_t *)&new_scdp->scd_refcnt);
}

/*
 * This routine is called by a process to remove itself from an SCD. It is
 * either called when the processes has detached from a segment or from
 * hat_free_start() as a result of calling exit.
 */
static void
sfmmu_leave_scd(sfmmu_t *sfmmup, uchar_t r_type)
{
        sf_scd_t *scdp = sfmmup->sfmmu_scdp;
        sf_srd_t *srdp =  sfmmup->sfmmu_srdp;
        hatlock_t *hatlockp = TSB_HASH(sfmmup);
        int i;

        ASSERT(scdp != NULL);
        ASSERT(srdp != NULL);

        if (sfmmup->sfmmu_free) {
                /*
                 * If the process is part of an SCD the sfmmu is unlinked
                 * from scd_sf_list.
                 */
                mutex_enter(&scdp->scd_mutex);
                sfmmu_from_scd_list(&scdp->scd_sf_list, sfmmup);
                mutex_exit(&scdp->scd_mutex);
                /*
                 * Update sfmmu_ttecnt to include the rgn ttecnt for rgns that
                 * are about to leave the SCD
                 */
                for (i = 0; i < mmu_page_sizes; i++) {
                        ASSERT(sfmmup->sfmmu_scdrttecnt[i] ==
                            scdp->scd_rttecnt[i]);
                        atomic_add_long(&sfmmup->sfmmu_ttecnt[i],
                            sfmmup->sfmmu_scdrttecnt[i]);
                        sfmmup->sfmmu_scdrttecnt[i] = 0;
                }
                sfmmup->sfmmu_scdp = NULL;

                SF_SCD_DECR_REF(srdp, scdp);
                return;
        }

        ASSERT(r_type != SFMMU_REGION_ISM ||
            SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY));
        ASSERT(scdp->scd_refcnt);
        ASSERT(!sfmmup->sfmmu_free);
        ASSERT(sfmmu_hat_lock_held(sfmmup));
        ASSERT(AS_LOCK_HELD(sfmmup->sfmmu_as));

        /*
         * Wait for ISM maps to be updated.
         */
        if (r_type != SFMMU_REGION_ISM) {
                while (SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY) &&
                    sfmmup->sfmmu_scdp != NULL) {
                        cv_wait(&sfmmup->sfmmu_tsb_cv,
                            HATLOCK_MUTEXP(hatlockp));
                }

                if (sfmmup->sfmmu_scdp == NULL) {
                        sfmmu_hat_exit(hatlockp);
                        return;
                }
                SFMMU_FLAGS_SET(sfmmup, HAT_ISMBUSY);
        }

        if (SFMMU_FLAGS_ISSET(sfmmup, HAT_JOIN_SCD)) {
                SFMMU_FLAGS_CLEAR(sfmmup, HAT_JOIN_SCD);
                /*
                 * Since HAT_JOIN_SCD was set our context
                 * is still invalid.
                 */
        } else {
                /*
                 * For a multi-thread process, we must stop
                 * all the other threads before leaving the scd.
                 */

                sfmmu_invalidate_ctx(sfmmup);
        }

        /* Clear all the rid's for ISM, delete flags, etc */
        ASSERT(SFMMU_FLAGS_ISSET(sfmmup, HAT_ISMBUSY));
        sfmmu_ism_hatflags(sfmmup, 0);

        /*
         * Update sfmmu_ttecnt to include the rgn ttecnt for rgns that
         * are in SCD before this sfmmup leaves the SCD.
         */
        for (i = 0; i < mmu_page_sizes; i++) {
                ASSERT(sfmmup->sfmmu_scdrttecnt[i] ==
                    scdp->scd_rttecnt[i]);
                atomic_add_long(&sfmmup->sfmmu_ttecnt[i],
                    sfmmup->sfmmu_scdrttecnt[i]);
                sfmmup->sfmmu_scdrttecnt[i] = 0;
                /* update ismttecnt to include SCD ism before hat leaves SCD */
                sfmmup->sfmmu_ismttecnt[i] += sfmmup->sfmmu_scdismttecnt[i];
                sfmmup->sfmmu_scdismttecnt[i] = 0;
        }
        /* update tsb0 inflation count */
        sfmmup->sfmmu_tsb0_4minflcnt += scdp->scd_sfmmup->sfmmu_tsb0_4minflcnt;

        if (r_type != SFMMU_REGION_ISM) {
                SFMMU_FLAGS_CLEAR(sfmmup, HAT_ISMBUSY);
        }
        sfmmup->sfmmu_scdp = NULL;

        sfmmu_hat_exit(hatlockp);

        /*
         * Unlink sfmmu from scd_sf_list this can be done without holding
         * the hat lock as we hold the sfmmu_as lock which prevents
         * hat_join_region from adding this thread to the scd again. Other
         * threads check if sfmmu_scdp is NULL under hat lock and if it's NULL
         * they won't get here, since sfmmu_leave_scd() clears sfmmu_scdp
         * while holding the hat lock.
         */
        mutex_enter(&scdp->scd_mutex);
        sfmmu_from_scd_list(&scdp->scd_sf_list, sfmmup);
        mutex_exit(&scdp->scd_mutex);
        SFMMU_STAT(sf_leave_scd);

        SF_SCD_DECR_REF(srdp, scdp);
        hatlockp = sfmmu_hat_enter(sfmmup);

}

/*
 * Unlink and free up an SCD structure with a reference count of 0.
 */
static void
sfmmu_destroy_scd(sf_srd_t *srdp, sf_scd_t *scdp, sf_region_map_t *scd_rmap)
{
        sfmmu_t *scsfmmup;
        sf_scd_t *sp;
        hatlock_t *shatlockp;
        int i, ret;

        mutex_enter(&srdp->srd_scd_mutex);
        for (sp = srdp->srd_scdp; sp != NULL; sp = sp->scd_next) {
                if (sp == scdp)
                        break;
        }
        if (sp == NULL || sp->scd_refcnt) {
                mutex_exit(&srdp->srd_scd_mutex);
                return;
        }

        /*
         * It is possible that the scd has been freed and reallocated with a
         * different region map while we've been waiting for the srd_scd_mutex.
         */
        SF_RGNMAP_EQUAL(scd_rmap, &sp->scd_region_map, ret);
        if (ret != 1) {
                mutex_exit(&srdp->srd_scd_mutex);
                return;
        }

        ASSERT(scdp->scd_sf_list == NULL);
        /*
         * Unlink scd from srd_scdp list.
         */
        sfmmu_remove_scd(&srdp->srd_scdp, scdp);
        mutex_exit(&srdp->srd_scd_mutex);

        sfmmu_unlink_scd_from_regions(srdp, scdp);

        /* Clear shared context tsb and release ctx */
        scsfmmup = scdp->scd_sfmmup;

        /*
         * create a barrier so that scd will not be destroyed
         * if other thread still holds the same shared hat lock.
         * E.g., sfmmu_tsbmiss_exception() needs to acquire the
         * shared hat lock before checking the shared tsb reloc flag.
         */
        shatlockp = sfmmu_hat_enter(scsfmmup);
        sfmmu_hat_exit(shatlockp);

        sfmmu_free_scd_tsbs(scsfmmup);

        for (i = 0; i < SFMMU_L1_HMERLINKS; i++) {
                if (scsfmmup->sfmmu_hmeregion_links[i] != NULL) {
                        kmem_free(scsfmmup->sfmmu_hmeregion_links[i],
                            SFMMU_L2_HMERLINKS_SIZE);
                        scsfmmup->sfmmu_hmeregion_links[i] = NULL;
                }
        }
        kmem_cache_free(sfmmuid_cache, scsfmmup);
        kmem_cache_free(scd_cache, scdp);
        SFMMU_STAT(sf_destroy_scd);
}

/*
 * Modifies the HAT_CTX1_FLAG for each of the ISM segments which correspond to
 * bits which are set in the ism_region_map parameter. This flag indicates to
 * the tsbmiss handler that mapping for these segments should be loaded using
 * the shared context.
 */
static void
sfmmu_ism_hatflags(sfmmu_t *sfmmup, int addflag)
{
        sf_scd_t *scdp = sfmmup->sfmmu_scdp;
        ism_blk_t *ism_blkp;
        ism_map_t *ism_map;
        int i, rid;

        ASSERT(sfmmup->sfmmu_iblk != NULL);
        ASSERT(scdp != NULL);
        /*
         * Note that the caller either set HAT_ISMBUSY flag or checked
         * under hat lock that HAT_ISMBUSY was not set by another thread.
         */
        ASSERT(sfmmu_hat_lock_held(sfmmup));

        ism_blkp = sfmmup->sfmmu_iblk;
        while (ism_blkp != NULL) {
                ism_map = ism_blkp->iblk_maps;
                for (i = 0; ism_map[i].imap_ismhat && i < ISM_MAP_SLOTS; i++) {
                        rid = ism_map[i].imap_rid;
                        if (rid == SFMMU_INVALID_ISMRID) {
                                continue;
                        }
                        ASSERT(rid >= 0 && rid < SFMMU_MAX_ISM_REGIONS);
                        if (SF_RGNMAP_TEST(scdp->scd_ismregion_map, rid) &&
                            addflag) {
                                ism_map[i].imap_hatflags |=
                                    HAT_CTX1_FLAG;
                        } else {
                                ism_map[i].imap_hatflags &=
                                    ~HAT_CTX1_FLAG;
                        }
                }
                ism_blkp = ism_blkp->iblk_next;
        }
}

static int
sfmmu_srd_lock_held(sf_srd_t *srdp)
{
        return (MUTEX_HELD(&srdp->srd_mutex));
}

/* ARGSUSED */
static int
sfmmu_scdcache_constructor(void *buf, void *cdrarg, int kmflags)
{
        sf_scd_t *scdp = (sf_scd_t *)buf;

        bzero(buf, sizeof (sf_scd_t));
        mutex_init(&scdp->scd_mutex, NULL, MUTEX_DEFAULT, NULL);
        return (0);
}

/* ARGSUSED */
static void
sfmmu_scdcache_destructor(void *buf, void *cdrarg)
{
        sf_scd_t *scdp = (sf_scd_t *)buf;

        mutex_destroy(&scdp->scd_mutex);
}

/*
 * The listp parameter is a pointer to a list of hmeblks which are partially
 * freed as result of calling sfmmu_hblk_hash_rm(), the last phase of the
 * freeing process is to cross-call all cpus to ensure that there are no
 * remaining cached references.
 *
 * If the local generation number is less than the global then we can free
 * hmeblks which are already on the pending queue as another cpu has completed
 * the cross-call.
 *
 * We cross-call to make sure that there are no threads on other cpus accessing
 * these hmblks and then complete the process of freeing them under the
 * following conditions:
 *      The total number of pending hmeblks is greater than the threshold
 *      The reserve list has fewer than HBLK_RESERVE_CNT hmeblks
 *      It is at least 1 second since the last time we cross-called
 *
 * Otherwise, we add the hmeblks to the per-cpu pending queue.
 */
static void
sfmmu_hblks_list_purge(struct hme_blk **listp, int dontfree)
{
        struct hme_blk *hblkp, *pr_hblkp = NULL;
        int             count = 0;
        cpuset_t        cpuset = cpu_ready_set;
        cpu_hme_pend_t  *cpuhp;
        timestruc_t     now;
        int             one_second_expired = 0;

        gethrestime_lasttick(&now);

        for (hblkp = *listp; hblkp != NULL; hblkp = hblkp->hblk_next) {
                ASSERT(hblkp->hblk_shw_bit == 0);
                ASSERT(hblkp->hblk_shared == 0);
                count++;
                pr_hblkp = hblkp;
        }

        cpuhp = &cpu_hme_pend[CPU->cpu_seqid];
        mutex_enter(&cpuhp->chp_mutex);

        if ((cpuhp->chp_count + count) == 0) {
                mutex_exit(&cpuhp->chp_mutex);
                return;
        }

        if ((now.tv_sec - cpuhp->chp_timestamp) > 1) {
                one_second_expired  = 1;
        }

        if (!dontfree && (freehblkcnt < HBLK_RESERVE_CNT ||
            (cpuhp->chp_count + count) > cpu_hme_pend_thresh ||
            one_second_expired)) {
                /* Append global list to local */
                if (pr_hblkp == NULL) {
                        *listp = cpuhp->chp_listp;
                } else {
                        pr_hblkp->hblk_next = cpuhp->chp_listp;
                }
                cpuhp->chp_listp = NULL;
                cpuhp->chp_count = 0;
                cpuhp->chp_timestamp = now.tv_sec;
                mutex_exit(&cpuhp->chp_mutex);

                kpreempt_disable();
                CPUSET_DEL(cpuset, CPU->cpu_id);
                xt_sync(cpuset);
                xt_sync(cpuset);
                kpreempt_enable();

                /*
                 * At this stage we know that no trap handlers on other
                 * cpus can have references to hmeblks on the list.
                 */
                sfmmu_hblk_free(listp);
        } else if (*listp != NULL) {
                pr_hblkp->hblk_next = cpuhp->chp_listp;
                cpuhp->chp_listp = *listp;
                cpuhp->chp_count += count;
                *listp = NULL;
                mutex_exit(&cpuhp->chp_mutex);
        } else {
                mutex_exit(&cpuhp->chp_mutex);
        }
}

/*
 * Add an hmeblk to the the hash list.
 */
void
sfmmu_hblk_hash_add(struct hmehash_bucket *hmebp, struct hme_blk *hmeblkp,
    uint64_t hblkpa)
{
        ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));
#ifdef  DEBUG
        if (hmebp->hmeblkp == NULL) {
                ASSERT(hmebp->hmeh_nextpa == HMEBLK_ENDPA);
        }
#endif /* DEBUG */

        hmeblkp->hblk_nextpa = hmebp->hmeh_nextpa;
        /*
         * Since the TSB miss handler now does not lock the hash chain before
         * walking it, make sure that the hmeblks nextpa is globally visible
         * before we make the hmeblk globally visible by updating the chain root
         * pointer in the hash bucket.
         */
        membar_producer();
        hmebp->hmeh_nextpa = hblkpa;
        hmeblkp->hblk_next = hmebp->hmeblkp;
        hmebp->hmeblkp = hmeblkp;

}

/*
 * This function is the first part of a 2 part process to remove an hmeblk
 * from the hash chain. In this phase we unlink the hmeblk from the hash chain
 * but leave the next physical pointer unchanged. The hmeblk is then linked onto
 * a per-cpu pending list using the virtual address pointer.
 *
 * TSB miss trap handlers that start after this phase will no longer see
 * this hmeblk. TSB miss handlers that still cache this hmeblk in a register
 * can still use it for further chain traversal because we haven't yet modifed
 * the next physical pointer or freed it.
 *
 * In the second phase of hmeblk removal we'll issue a barrier xcall before
 * we reuse or free this hmeblk. This will make sure all lingering references to
 * the hmeblk after first phase disappear before we finally reclaim it.
 * This scheme eliminates the need for TSB miss handlers to lock hmeblk chains
 * during their traversal.
 *
 * The hmehash_mutex must be held when calling this function.
 *
 * Input:
 *       hmebp - hme hash bucket pointer
 *       hmeblkp - address of hmeblk to be removed
 *       pr_hblk - virtual address of previous hmeblkp
 *       listp - pointer to list of hmeblks linked by virtual address
 *       free_now flag - indicates that a complete removal from the hash chains
 *                       is necessary.
 *
 * It is inefficient to use the free_now flag as a cross-call is required to
 * remove a single hmeblk from the hash chain but is necessary when hmeblks are
 * in short supply.
 */
void
sfmmu_hblk_hash_rm(struct hmehash_bucket *hmebp, struct hme_blk *hmeblkp,
    struct hme_blk *pr_hblk, struct hme_blk **listp, int free_now)
{
        int shw_size, vshift;
        struct hme_blk *shw_hblkp;
        uint_t          shw_mask, newshw_mask;
        caddr_t         vaddr;
        int             size;
        cpuset_t cpuset = cpu_ready_set;

        ASSERT(SFMMU_HASH_LOCK_ISHELD(hmebp));

        if (hmebp->hmeblkp == hmeblkp) {
                hmebp->hmeh_nextpa = hmeblkp->hblk_nextpa;
                hmebp->hmeblkp = hmeblkp->hblk_next;
        } else {
                pr_hblk->hblk_nextpa = hmeblkp->hblk_nextpa;
                pr_hblk->hblk_next = hmeblkp->hblk_next;
        }

        size = get_hblk_ttesz(hmeblkp);
        shw_hblkp = hmeblkp->hblk_shadow;
        if (shw_hblkp) {
                ASSERT(hblktosfmmu(hmeblkp) != KHATID);
                ASSERT(!hmeblkp->hblk_shared);
#ifdef  DEBUG
                if (mmu_page_sizes == max_mmu_page_sizes) {
                        ASSERT(size < TTE256M);
                } else {
                        ASSERT(size < TTE4M);
                }
#endif /* DEBUG */

                shw_size = get_hblk_ttesz(shw_hblkp);
                vaddr = (caddr_t)get_hblk_base(hmeblkp);
                vshift = vaddr_to_vshift(shw_hblkp->hblk_tag, vaddr, shw_size);
                ASSERT(vshift < 8);
                /*
                 * Atomically clear shadow mask bit
                 */
                do {
                        shw_mask = shw_hblkp->hblk_shw_mask;
                        ASSERT(shw_mask & (1 << vshift));
                        newshw_mask = shw_mask & ~(1 << vshift);
                        newshw_mask = atomic_cas_32(&shw_hblkp->hblk_shw_mask,
                            shw_mask, newshw_mask);
                } while (newshw_mask != shw_mask);
                hmeblkp->hblk_shadow = NULL;
        }
        hmeblkp->hblk_shw_bit = 0;

        if (hmeblkp->hblk_shared) {
#ifdef  DEBUG
                sf_srd_t        *srdp;
                sf_region_t     *rgnp;
                uint_t          rid;

                srdp = hblktosrd(hmeblkp);
                ASSERT(srdp != NULL && srdp->srd_refcnt != 0);
                rid = hmeblkp->hblk_tag.htag_rid;
                ASSERT(SFMMU_IS_SHMERID_VALID(rid));
                ASSERT(rid < SFMMU_MAX_HME_REGIONS);
                rgnp = srdp->srd_hmergnp[rid];
                ASSERT(rgnp != NULL);
                SFMMU_VALIDATE_SHAREDHBLK(hmeblkp, srdp, rgnp, rid);
#endif /* DEBUG */
                hmeblkp->hblk_shared = 0;
        }
        if (free_now) {
                kpreempt_disable();
                CPUSET_DEL(cpuset, CPU->cpu_id);
                xt_sync(cpuset);
                xt_sync(cpuset);
                kpreempt_enable();

                hmeblkp->hblk_nextpa = HMEBLK_ENDPA;
                hmeblkp->hblk_next = NULL;
        } else {
                /* Append hmeblkp to listp for processing later. */
                hmeblkp->hblk_next = *listp;
                *listp = hmeblkp;
        }
}

/*
 * This routine is called when memory is in short supply and returns a free
 * hmeblk of the requested size from the cpu pending lists.
 */
static struct hme_blk *
sfmmu_check_pending_hblks(int size)
{
        int i;
        struct hme_blk *hmeblkp = NULL, *last_hmeblkp;
        int found_hmeblk;
        cpuset_t cpuset = cpu_ready_set;
        cpu_hme_pend_t *cpuhp;

        /* Flush cpu hblk pending queues */
        for (i = 0; i < NCPU; i++) {
                cpuhp = &cpu_hme_pend[i];
                if (cpuhp->chp_listp != NULL)  {
                        mutex_enter(&cpuhp->chp_mutex);
                        if (cpuhp->chp_listp == NULL)  {
                                mutex_exit(&cpuhp->chp_mutex);
                                continue;
                        }
                        found_hmeblk = 0;
                        last_hmeblkp = NULL;
                        for (hmeblkp = cpuhp->chp_listp; hmeblkp != NULL;
                            hmeblkp = hmeblkp->hblk_next) {
                                if (get_hblk_ttesz(hmeblkp) == size) {
                                        if (last_hmeblkp == NULL) {
                                                cpuhp->chp_listp =
                                                    hmeblkp->hblk_next;
                                        } else {
                                                last_hmeblkp->hblk_next =
                                                    hmeblkp->hblk_next;
                                        }
                                        ASSERT(cpuhp->chp_count > 0);
                                        cpuhp->chp_count--;
                                        found_hmeblk = 1;
                                        break;
                                } else {
                                        last_hmeblkp = hmeblkp;
                                }
                        }
                        mutex_exit(&cpuhp->chp_mutex);

                        if (found_hmeblk) {
                                kpreempt_disable();
                                CPUSET_DEL(cpuset, CPU->cpu_id);
                                xt_sync(cpuset);
                                xt_sync(cpuset);
                                kpreempt_enable();
                                return (hmeblkp);
                        }
                }
        }
        return (NULL);
}