/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _VM_SEG_KP_H
#define _VM_SEG_KP_H

/*
 * segkp (as in kernel pageable) is a segment driver that supports allocation
 * of page-aligned variable size of vm resources.
 *
 * Each vm resource represents a page-aligned range of virtual addresses.
 * The caller may specify whether the resource should include a redzone,
 * be locked down, or be zero initialized.
 */

#include <vm/seg.h>
#include <sys/vmem.h>

#ifdef  __cplusplus
extern "C" {
#endif

#ifdef  _KERNEL

/*
 * Private information per overall segkp segment (as opposed
 * to per resource within segment). There are as many anon slots
 * allocated as there there are pages in the segment.
 */
struct segkp_segdata {
        struct anon_hdr *kpsd_anon;     /* anon structs */
        vmem_t          *kpsd_arena;    /* virtual memory descriptor */
        struct segkp_data **kpsd_hash;  /* Hash table for lookups */
};

#define SEGKP_VMEM(seg) (((struct segkp_segdata *)(seg)->s_data)->kpsd_arena)

/*
 * A hash table is used to aid in the lookup of a kpd's based on vaddr.
 * Since the heaviest use of segkp occurs from segkp_*get and segkp_*release,
 * the hashing is based on the vaddr used by these routines.
 */
#define SEGKP_HASHSZ            256     /* power of two */
#define SEGKP_HASHMASK          (SEGKP_HASHSZ - 1)
#define SEGKP_HASH(vaddr)       \
        ((int)(((uintptr_t)vaddr >> PAGESHIFT) & SEGKP_HASHMASK))

struct segkp_data {
        kmutex_t        kp_lock;        /* per resource lock */
        caddr_t         kp_base;        /* starting addr of chunk */
        size_t          kp_len;         /* # of bytes */
        uint_t          kp_flags;       /* state info */
        int             kp_cookie;      /* index into cache array */
        ulong_t         kp_anon_idx;    /* index into main anon array */
                                        /* in segkp_segdata */
        struct anon_hdr *kp_anon;       /* anon structs */
        struct segkp_data *kp_next;     /* ptr to next in hash chain */
};

/*
 * Flag bits
 *
 */
#define KPD_ZERO        0x01            /* initialize resource with 0 */
#define KPD_LOCKED      0x02            /* resources locked */
#define KPD_NO_ANON     0x04            /* no swap resources required */
#define KPD_HASREDZONE  0x08            /* include a redzone */
#define KPD_NOWAIT      0x10            /* do not wait for res. if unavail. */
#define KPD_WRITEDIRTY  0x20            /* dirty pages should be flushed */
#define KPD_HASAMP      0x40            /* anon_hdr managed by caller */

/*
 * A cache of segkp elements may be created via segkp_cache_init().
 * The elements on the freelist all have the same len and flags value.
 * The cookie passed to the client is an index into the freelist array.
 */
struct segkp_cache  {
        int             kpf_max;                /* max # of elements allowed */
        int             kpf_count;              /* current no. of elments */
        int             kpf_inuse;              /* list inuse */
        uint_t          kpf_flags;              /* seg_kp flag value */
        size_t          kpf_len;                /* len of resource */
        struct seg      *kpf_seg;               /* segment */
        struct segkp_data *kpf_list;            /* list of kpd's */
};
#define SEGKP_MAX_CACHE         4       /* Number of caches maintained */

/*
 * Define redzone, and stack_to_memory macros.
 * The redzone is PAGESIZE bytes.
 */
#ifdef  STACK_GROWTH_DOWN
#define KPD_REDZONE(kpd)        (0)
#define stom(v, flags)  (((flags) & KPD_HASREDZONE) ? (v) + PAGESIZE : (v))

#else   /* STACK_GROWTH_DOWN */

#define KPD_REDZONE(kpd) (btop(kpd->kp_len) - 1)
#define stom(v) (v)
#endif  /* STACK_GROWTH_DOWN */

#define SEGKP_MAPLEN(len, flags) \
        (((flags) & KPD_HASREDZONE) ? (len) - PAGESIZE : (len))

extern  struct seg *segkp;
/* If segkp becomes more than one seg this test will need changing. */
#define SEG_IS_SEGKP(SEG)       ((SEG) == segkp)

/*
 * Public routine declarations not part of the segment ops vector go here.
 */
int     segkp_create(struct seg *seg);
caddr_t segkp_get(struct seg *seg, size_t len, uint_t flags);
void    segkp_release(struct seg *seg, caddr_t vaddr);
void *  segkp_cache_init(struct seg *seg, int maxsize, size_t len,
                uint_t flags);
void    segkp_cache_free();
caddr_t segkp_cache_get(void *cookie);
int     segkp_map_red(void);
void    segkp_unmap_red(void);
size_t  swapsize(caddr_t v);

/* Special currently only used by schedctl. */
struct anon_map;        /* Make the compiler happy about the next line. */
caddr_t segkp_get_withanonmap(struct seg *, size_t, uint_t, struct anon_map *);

/*
 * We allow explicit calls to segkp_fault, even though it's part
 * of the segkp ops vector.
 */
faultcode_t segkp_fault(struct hat *hat, struct seg *seg, caddr_t addr,
        size_t len, enum fault_type type, enum seg_rw rw);

#endif  /* _KERNEL */

#ifdef  __cplusplus
}
#endif

#endif  /* _VM_SEG_KP_H */