1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2000 Peter Wemm 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/conf.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/proc.h> 37 #include <sys/mutex.h> 38 #include <sys/mman.h> 39 #include <sys/rwlock.h> 40 #include <sys/sysctl.h> 41 #include <sys/user.h> 42 43 #include <vm/vm.h> 44 #include <vm/vm_param.h> 45 #include <vm/vm_object.h> 46 #include <vm/vm_page.h> 47 #include <vm/vm_pageout.h> 48 #include <vm/vm_pager.h> 49 50 /* list of phys pager objects */ 51 static struct pagerlst phys_pager_object_list; 52 /* protect access to phys_pager_object_list */ 53 static struct mtx phys_pager_mtx; 54 55 static int default_phys_pager_getpages(vm_object_t object, vm_page_t *m, 56 int count, int *rbehind, int *rahead); 57 static int default_phys_pager_populate(vm_object_t object, vm_pindex_t pidx, 58 int fault_type, vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last); 59 static boolean_t default_phys_pager_haspage(vm_object_t object, 60 vm_pindex_t pindex, int *before, int *after); 61 const struct phys_pager_ops default_phys_pg_ops = { 62 .phys_pg_getpages = default_phys_pager_getpages, 63 .phys_pg_populate = default_phys_pager_populate, 64 .phys_pg_haspage = default_phys_pager_haspage, 65 .phys_pg_ctor = NULL, 66 .phys_pg_dtor = NULL, 67 }; 68 69 static void 70 phys_pager_init(void) 71 { 72 73 TAILQ_INIT(&phys_pager_object_list); 74 mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF); 75 } 76 77 vm_object_t 78 phys_pager_allocate(void *handle, const struct phys_pager_ops *ops, void *data, 79 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred) 80 { 81 vm_object_t object, object1; 82 vm_pindex_t pindex; 83 bool init; 84 85 /* 86 * Offset should be page aligned. 87 */ 88 if (foff & PAGE_MASK) 89 return (NULL); 90 91 pindex = OFF_TO_IDX(foff + PAGE_MASK + size); 92 init = true; 93 94 if (handle != NULL) { 95 mtx_lock(&phys_pager_mtx); 96 /* 97 * Look up pager, creating as necessary. 98 */ 99 object1 = NULL; 100 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 101 if (object == NULL) { 102 /* 103 * Allocate object and associate it with the pager. 104 */ 105 mtx_unlock(&phys_pager_mtx); 106 object1 = vm_object_allocate(OBJT_PHYS, pindex); 107 mtx_lock(&phys_pager_mtx); 108 object = vm_pager_object_lookup(&phys_pager_object_list, 109 handle); 110 if (object != NULL) { 111 /* 112 * We raced with other thread while 113 * allocating object. 114 */ 115 if (pindex > object->size) 116 object->size = pindex; 117 init = false; 118 } else { 119 object = object1; 120 object1 = NULL; 121 object->handle = handle; 122 object->un_pager.phys.ops = ops; 123 object->un_pager.phys.data_ptr = data; 124 if (ops->phys_pg_populate != NULL) 125 vm_object_set_flag(object, OBJ_POPULATE); 126 TAILQ_INSERT_TAIL(&phys_pager_object_list, 127 object, pager_object_list); 128 } 129 } else { 130 if (pindex > object->size) 131 object->size = pindex; 132 } 133 mtx_unlock(&phys_pager_mtx); 134 vm_object_deallocate(object1); 135 } else { 136 object = vm_object_allocate(OBJT_PHYS, pindex); 137 object->un_pager.phys.ops = ops; 138 object->un_pager.phys.data_ptr = data; 139 if (ops->phys_pg_populate != NULL) 140 vm_object_set_flag(object, OBJ_POPULATE); 141 } 142 if (init && ops->phys_pg_ctor != NULL) 143 ops->phys_pg_ctor(object, prot, foff, cred); 144 145 return (object); 146 } 147 148 static vm_object_t 149 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 150 vm_ooffset_t foff, struct ucred *ucred) 151 { 152 return (phys_pager_allocate(handle, &default_phys_pg_ops, NULL, 153 size, prot, foff, ucred)); 154 } 155 156 static void 157 phys_pager_dealloc(vm_object_t object) 158 { 159 160 if (object->handle != NULL) { 161 VM_OBJECT_WUNLOCK(object); 162 mtx_lock(&phys_pager_mtx); 163 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 164 mtx_unlock(&phys_pager_mtx); 165 VM_OBJECT_WLOCK(object); 166 } 167 object->type = OBJT_DEAD; 168 if (object->un_pager.phys.ops->phys_pg_dtor != NULL) 169 object->un_pager.phys.ops->phys_pg_dtor(object); 170 object->handle = NULL; 171 } 172 173 /* 174 * Fill as many pages as vm_fault has allocated for us. 175 */ 176 static int 177 default_phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, 178 int *rbehind, int *rahead) 179 { 180 int i; 181 182 for (i = 0; i < count; i++) { 183 if (vm_page_none_valid(m[i])) { 184 if ((m[i]->flags & PG_ZERO) == 0) 185 pmap_zero_page(m[i]); 186 vm_page_valid(m[i]); 187 } 188 KASSERT(vm_page_all_valid(m[i]), 189 ("phys_pager_getpages: partially valid page %p", m[i])); 190 KASSERT(m[i]->dirty == 0, 191 ("phys_pager_getpages: dirty page %p", m[i])); 192 } 193 if (rbehind) 194 *rbehind = 0; 195 if (rahead) 196 *rahead = 0; 197 return (VM_PAGER_OK); 198 } 199 200 static int 201 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 202 int *rahead) 203 { 204 return (object->un_pager.phys.ops->phys_pg_getpages(object, m, 205 count, rbehind, rahead)); 206 } 207 208 /* 209 * Implement a pretty aggressive clustered getpages strategy. Hint that 210 * everything in an entire 4MB window should be prefaulted at once. 211 * 212 * 4MB (1024 slots per page table page) is convenient for x86, 213 * but may not be for other arches. 214 */ 215 #ifndef PHYSCLUSTER 216 #define PHYSCLUSTER 1024 217 #endif 218 static int phys_pager_cluster = PHYSCLUSTER; 219 SYSCTL_INT(_vm, OID_AUTO, phys_pager_cluster, CTLFLAG_RWTUN, 220 &phys_pager_cluster, 0, 221 "prefault window size for phys pager"); 222 223 /* 224 * Max hint to vm_page_alloc() about the further allocation needs 225 * inside the phys_pager_populate() loop. The number of bits used to 226 * implement VM_ALLOC_COUNT() determines the hard limit on this value. 227 * That limit is currently 65535. 228 */ 229 #define PHYSALLOC 16 230 231 static int 232 default_phys_pager_populate(vm_object_t object, vm_pindex_t pidx, 233 int fault_type __unused, vm_prot_t max_prot __unused, vm_pindex_t *first, 234 vm_pindex_t *last) 235 { 236 vm_page_t m; 237 vm_pindex_t base, end, i; 238 int ahead; 239 240 base = rounddown(pidx, phys_pager_cluster); 241 end = base + phys_pager_cluster - 1; 242 if (end >= object->size) 243 end = object->size - 1; 244 if (*first > base) 245 base = *first; 246 if (end > *last) 247 end = *last; 248 *first = base; 249 *last = end; 250 251 for (i = base; i <= end; i++) { 252 ahead = MIN(end - i, PHYSALLOC); 253 m = vm_page_grab(object, i, 254 VM_ALLOC_NORMAL | VM_ALLOC_COUNT(ahead)); 255 if (!vm_page_all_valid(m)) 256 vm_page_zero_invalid(m, TRUE); 257 KASSERT(m->dirty == 0, 258 ("phys_pager_populate: dirty page %p", m)); 259 } 260 return (VM_PAGER_OK); 261 } 262 263 static int 264 phys_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type, 265 vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last) 266 { 267 return (object->un_pager.phys.ops->phys_pg_populate(object, pidx, 268 fault_type, max_prot, first, last)); 269 } 270 271 static void 272 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags, 273 int *rtvals) 274 { 275 276 panic("phys_pager_putpage called"); 277 } 278 279 static boolean_t 280 default_phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 281 int *after) 282 { 283 vm_pindex_t base, end; 284 285 base = rounddown(pindex, phys_pager_cluster); 286 end = base + phys_pager_cluster - 1; 287 if (before != NULL) 288 *before = pindex - base; 289 if (after != NULL) 290 *after = end - pindex; 291 return (TRUE); 292 } 293 294 static boolean_t 295 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 296 int *after) 297 { 298 return (object->un_pager.phys.ops->phys_pg_haspage(object, pindex, 299 before, after)); 300 } 301 302 const struct pagerops physpagerops = { 303 .pgo_kvme_type = KVME_TYPE_PHYS, 304 .pgo_init = phys_pager_init, 305 .pgo_alloc = phys_pager_alloc, 306 .pgo_dealloc = phys_pager_dealloc, 307 .pgo_getpages = phys_pager_getpages, 308 .pgo_putpages = phys_pager_putpages, 309 .pgo_haspage = phys_pager_haspage, 310 .pgo_populate = phys_pager_populate, 311 }; 312