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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2003 Peter Wemm.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department and William Jolitz of UUNET Technologies Inc.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 __SYS__PV_ENTRY_H__
#define __SYS__PV_ENTRY_H__
#include <sys/param.h>
struct pmap;
/*
* For each vm_page_t, there is a list of all currently valid virtual
* mappings of that page. An entry is a pv_entry_t, the list is pv_list.
*/
typedef struct pv_entry {
vm_offset_t pv_va; /* virtual address for mapping */
TAILQ_ENTRY(pv_entry) pv_next;
} *pv_entry_t;
/*
* pv_entries are allocated in chunks per-process. This avoids the
* need to track per-pmap assignments. Each chunk is the size of a
* single page.
*
* Chunks store a bitmap in pc_map[] to track which entries in the
* bitmap are free (1) or used (0). PC_FREEL is the value of the last
* entry in the pc_map[] array when a chunk is completely free. PC_FREEN
* is the value of all the other entries in the pc_map[] array when a
* chunk is completely free.
*/
#if PAGE_SIZE == 4 * 1024
#ifdef __LP64__
#define _NPCPV 168
#define _NPAD 0
#else
#define _NPCPV 336
#define _NPAD 0
#endif
#elif PAGE_SIZE == 16 * 1024
#ifdef __LP64__
#define _NPCPV 677
#define _NPAD 1
#endif
#endif
#ifndef _NPCPV
#error Unsupported page size
#endif
/* Support clang < 14 */
#ifndef __LONG_WIDTH__
#define __LONG_WIDTH__ (__CHAR_BIT__ * __SIZEOF_LONG__)
#endif
#define _NPCM howmany(_NPCPV, __LONG_WIDTH__)
#define PC_FREEN ~0ul
#define PC_FREEL ((1ul << (_NPCPV % __LONG_WIDTH__)) - 1)
#define PV_CHUNK_HEADER \
struct pmap *pc_pmap; \
TAILQ_ENTRY(pv_chunk) pc_list; \
unsigned long pc_map[_NPCM]; /* bitmap; 1 = free */ \
TAILQ_ENTRY(pv_chunk) pc_lru;
struct pv_chunk_header {
PV_CHUNK_HEADER
};
struct pv_chunk {
PV_CHUNK_HEADER
struct pv_entry pc_pventry[_NPCPV];
unsigned long pc_pad[_NPAD];
};
_Static_assert(sizeof(struct pv_chunk) == PAGE_SIZE,
"PV entry chunk size mismatch");
#ifdef _KERNEL
static __inline bool
pc_is_full(struct pv_chunk *pc)
{
for (u_int i = 0; i < _NPCM; i++) {
if (pc->pc_map[i] != 0)
return (false);
}
return (true);
}
static __inline bool
pc_is_free(struct pv_chunk *pc)
{
for (u_int i = 0; i < _NPCM - 1; i++) {
if (pc->pc_map[i] != PC_FREEN)
return (false);
}
return (pc->pc_map[_NPCM - 1] == PC_FREEL);
}
static __inline struct pv_chunk *
pv_to_chunk(pv_entry_t pv)
{
return ((struct pv_chunk *)((uintptr_t)pv & ~(uintptr_t)PAGE_MASK));
}
#define PV_PMAP(pv) (pv_to_chunk(pv)->pc_pmap)
#endif
#endif /* !__SYS__PV_ENTRY_H__ */
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