1 /* 2 * Copyright (c) 2000 Peter Wemm 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28 #include <sys/param.h> 29 #include <sys/systm.h> 30 #include <sys/linker_set.h> 31 #include <sys/conf.h> 32 #include <sys/kernel.h> 33 #include <sys/lock.h> 34 #include <sys/proc.h> 35 #include <sys/mutex.h> 36 #include <sys/mman.h> 37 #include <sys/sysctl.h> 38 39 #include <vm/vm.h> 40 #include <vm/vm_object.h> 41 #include <vm/vm_page.h> 42 #include <vm/vm_pager.h> 43 #include <vm/vm_zone.h> 44 45 /* prevent concurrant creation races */ 46 static int phys_pager_alloc_lock; 47 /* list of device pager objects */ 48 static struct pagerlst phys_pager_object_list; 49 /* protect access to phys_pager_object_list */ 50 static struct mtx phys_pager_mtx; 51 52 static void 53 phys_pager_init(void) 54 { 55 56 TAILQ_INIT(&phys_pager_object_list); 57 mtx_init(&phys_pager_mtx, "phys_pager list", MTX_DEF); 58 } 59 60 static vm_object_t 61 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 62 vm_ooffset_t foff) 63 { 64 vm_object_t object; 65 66 GIANT_REQUIRED; 67 68 /* 69 * Offset should be page aligned. 70 */ 71 if (foff & PAGE_MASK) 72 return (NULL); 73 74 size = round_page(size); 75 76 if (handle != NULL) { 77 /* 78 * Lock to prevent object creation race condition. 79 */ 80 while (phys_pager_alloc_lock) { 81 phys_pager_alloc_lock = -1; 82 tsleep(&phys_pager_alloc_lock, PVM, "swpalc", 0); 83 } 84 phys_pager_alloc_lock = 1; 85 86 /* 87 * Look up pager, creating as necessary. 88 */ 89 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 90 if (object == NULL) { 91 /* 92 * Allocate object and associate it with the pager. 93 */ 94 object = vm_object_allocate(OBJT_PHYS, 95 OFF_TO_IDX(foff + size)); 96 object->handle = handle; 97 mtx_lock(&phys_pager_mtx); 98 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 99 pager_object_list); 100 mtx_unlock(&phys_pager_mtx); 101 } else { 102 /* 103 * Gain a reference to the object. 104 */ 105 vm_object_reference(object); 106 if (OFF_TO_IDX(foff + size) > object->size) 107 object->size = OFF_TO_IDX(foff + size); 108 } 109 if (phys_pager_alloc_lock == -1) 110 wakeup(&phys_pager_alloc_lock); 111 phys_pager_alloc_lock = 0; 112 113 } else { 114 object = vm_object_allocate(OBJT_PHYS, 115 OFF_TO_IDX(foff + size)); 116 } 117 118 return (object); 119 } 120 121 static void 122 phys_pager_dealloc(vm_object_t object) 123 { 124 125 if (object->handle != NULL) { 126 mtx_lock(&phys_pager_mtx); 127 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 128 mtx_unlock(&phys_pager_mtx); 129 } 130 } 131 132 static int 133 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 134 { 135 int i, s; 136 137 s = splvm(); 138 /* 139 * Fill as many pages as vm_fault has allocated for us. 140 */ 141 for (i = 0; i < count; i++) { 142 if ((m[i]->flags & PG_ZERO) == 0) 143 vm_page_zero_fill(m[i]); 144 vm_page_flag_set(m[i], PG_ZERO); 145 /* Switch off pv_entries */ 146 vm_page_unmanage(m[i]); 147 m[i]->valid = VM_PAGE_BITS_ALL; 148 m[i]->dirty = 0; 149 /* The requested page must remain busy, the others not. */ 150 if (reqpage != i) { 151 vm_page_flag_clear(m[i], PG_BUSY); 152 m[i]->busy = 0; 153 } 154 } 155 splx(s); 156 157 return (VM_PAGER_OK); 158 } 159 160 static void 161 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 162 int *rtvals) 163 { 164 165 panic("phys_pager_putpage called"); 166 } 167 168 /* 169 * Implement a pretty aggressive clustered getpages strategy. Hint that 170 * everything in an entire 4MB window should be prefaulted at once. 171 * 172 * XXX 4MB (1024 slots per page table page) is convenient for x86, 173 * but may not be for other arches. 174 */ 175 #ifndef PHYSCLUSTER 176 #define PHYSCLUSTER 1024 177 #endif 178 static boolean_t 179 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 180 int *after) 181 { 182 vm_pindex_t base, end; 183 184 base = pindex & (~(PHYSCLUSTER - 1)); 185 end = base + (PHYSCLUSTER - 1); 186 if (before != NULL) 187 *before = pindex - base; 188 if (after != NULL) 189 *after = end - pindex; 190 return (TRUE); 191 } 192 193 struct pagerops physpagerops = { 194 phys_pager_init, 195 phys_pager_alloc, 196 phys_pager_dealloc, 197 phys_pager_getpages, 198 phys_pager_putpages, 199 phys_pager_haspage, 200 NULL 201 }; 202