/*      $NetBSD: pmap_pv.h,v 1.17 2020/03/17 22:29:19 ad Exp $  */

/*-
 * Copyright (c)2008 YAMAMOTO Takashi,
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _X86_PMAP_PV_H_
#define _X86_PMAP_PV_H_

#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/rbtree.h>

struct vm_page;
struct pmap_page;

/*
 * structures to track P->V mapping
 *
 * this file is intended to be minimum as it's included by <machine/vmparam.h>.
 */

/*
 * pv_pte: describe a pte
 */

struct pv_pte {
        struct vm_page *pte_ptp;        /* PTP; NULL for pmap_kernel() */
        vaddr_t pte_va;                 /* VA */
};

/*
 * pv_entry: plug pv_pte into lists.  32 bytes on i386, 64 on amd64.
 */

struct pv_entry {
        struct pv_pte pve_pte;          /* should be the first member */
        LIST_ENTRY(pv_entry) pve_list;  /* on pmap_page::pp_pvlist */
        rb_node_t pve_rb;               /* red-black tree node */
        struct pmap_page *pve_pp;       /* backpointer to mapped page */
};
#define pve_next        pve_list.le_next

/*
 * pmap_page: a structure which is embedded in each vm_page.
 */

struct pmap_page {
        union {
                /* PTPs */
                rb_tree_t rb;

                /* PTPs, when being freed */
                LIST_ENTRY(vm_page) link;

                /* Non-PTPs (i.e. normal pages) */
                struct {
                        struct pv_pte pte;
                        LIST_HEAD(, pv_entry) pvlist;
                        uint8_t attrs;
                } s;
        } pp_u;
        kmutex_t        pp_lock;
#define pp_rb           pp_u.rb
#define pp_link         pp_u.link
#define pp_pte          pp_u.s.pte
#define pp_pvlist       pp_u.s.pvlist
#define pp_attrs        pp_u.s.attrs
};

#define PP_ATTRS_D      0x01    /* Dirty */
#define PP_ATTRS_A      0x02    /* Accessed */
#define PP_ATTRS_W      0x04    /* Writable */

#define PMAP_PAGE_INIT(pp) \
do { \
        LIST_INIT(&(pp)->pp_pvlist); \
        mutex_init(&(pp)->pp_lock, MUTEX_NODEBUG, IPL_VM); \
} while (/* CONSTCOND */ 0);

#endif /* !_X86_PMAP_PV_H_ */