1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2003 Peter Wemm. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * the Systems Programming Group of the University of Utah Computer 9 * Science Department and William Jolitz of UUNET Technologies Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef __SYS__PV_ENTRY_H__ 37 #define __SYS__PV_ENTRY_H__ 38 39 #include <sys/param.h> 40 41 struct pmap; 42 43 /* 44 * For each vm_page_t, there is a list of all currently valid virtual 45 * mappings of that page. An entry is a pv_entry_t, the list is pv_list. 46 */ 47 typedef struct pv_entry { 48 vm_offset_t pv_va; /* virtual address for mapping */ 49 TAILQ_ENTRY(pv_entry) pv_next; 50 } *pv_entry_t; 51 52 /* 53 * pv_entries are allocated in chunks per-process. This avoids the 54 * need to track per-pmap assignments. Each chunk is the size of a 55 * single page. 56 * 57 * Chunks store a bitmap in pc_map[] to track which entries in the 58 * bitmap are free (1) or used (0). PC_FREEL is the value of the last 59 * entry in the pc_map[] array when a chunk is completely free. PC_FREEN 60 * is the value of all the other entries in the pc_map[] array when a 61 * chunk is completely free. 62 */ 63 #if PAGE_SIZE == 4 * 1024 64 #ifdef __LP64__ 65 #define _NPCPV 168 66 #define _NPAD 0 67 #else 68 #define _NPCPV 336 69 #define _NPAD 0 70 #endif 71 #elif PAGE_SIZE == 16 * 1024 72 #ifdef __LP64__ 73 #define _NPCPV 677 74 #define _NPAD 1 75 #endif 76 #endif 77 78 #ifndef _NPCPV 79 #error Unsupported page size 80 #endif 81 82 /* Support clang < 14 */ 83 #ifndef __LONG_WIDTH__ 84 #define __LONG_WIDTH__ (__CHAR_BIT__ * __SIZEOF_LONG__) 85 #endif 86 87 #define _NPCM howmany(_NPCPV, __LONG_WIDTH__) 88 #define PC_FREEN ~0ul 89 #define PC_FREEL ((1ul << (_NPCPV % __LONG_WIDTH__)) - 1) 90 91 #define PV_CHUNK_HEADER \ 92 struct pmap *pc_pmap; \ 93 TAILQ_ENTRY(pv_chunk) pc_list; \ 94 unsigned long pc_map[_NPCM]; /* bitmap; 1 = free */ \ 95 TAILQ_ENTRY(pv_chunk) pc_lru; 96 97 struct pv_chunk_header { 98 PV_CHUNK_HEADER 99 }; 100 101 struct pv_chunk { 102 PV_CHUNK_HEADER 103 struct pv_entry pc_pventry[_NPCPV]; 104 unsigned long pc_pad[_NPAD]; 105 }; 106 107 _Static_assert(sizeof(struct pv_chunk) == PAGE_SIZE, 108 "PV entry chunk size mismatch"); 109 110 #ifdef _KERNEL 111 static __inline bool 112 pc_is_full(struct pv_chunk *pc) 113 { 114 for (u_int i = 0; i < _NPCM; i++) { 115 if (pc->pc_map[i] != 0) 116 return (false); 117 } 118 return (true); 119 } 120 121 static __inline bool 122 pc_is_free(struct pv_chunk *pc) 123 { 124 for (u_int i = 0; i < _NPCM - 1; i++) { 125 if (pc->pc_map[i] != PC_FREEN) 126 return (false); 127 } 128 return (pc->pc_map[_NPCM - 1] == PC_FREEL); 129 } 130 131 static __inline struct pv_chunk * 132 pv_to_chunk(pv_entry_t pv) 133 { 134 return ((struct pv_chunk *)((uintptr_t)pv & ~(uintptr_t)PAGE_MASK)); 135 } 136 137 #define PV_PMAP(pv) (pv_to_chunk(pv)->pc_pmap) 138 #endif 139 140 #endif /* !__SYS__PV_ENTRY_H__ */ 141