Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/vm/device_pager.c
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1 /*- 2 * Copyright (c) 1990 University of Utah. 3 * Copyright (c) 1991, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the Systems Programming Group of the University of Utah Computer 8 * Science Department. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/conf.h> 43 #include <sys/lock.h> 44 #include <sys/proc.h> 45 #include <sys/mutex.h> 46 #include <sys/mman.h> 47 #include <sys/rwlock.h> 48 #include <sys/sx.h> 49 #include <sys/vmmeter.h> 50 51 #include <vm/vm.h> 52 #include <vm/vm_param.h> 53 #include <vm/vm_object.h> 54 #include <vm/vm_page.h> 55 #include <vm/vm_pager.h> 56 #include <vm/vm_phys.h> 57 #include <vm/uma.h> 58 59 static void dev_pager_init(void); 60 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 61 vm_ooffset_t, struct ucred *); 62 static void dev_pager_dealloc(vm_object_t); 63 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); 64 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 65 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 66 static void dev_pager_free_page(vm_object_t object, vm_page_t m); 67 static int dev_pager_populate(vm_object_t object, vm_pindex_t pidx, 68 int fault_type, vm_prot_t, vm_pindex_t *first, vm_pindex_t *last); 69 70 /* list of device pager objects */ 71 static struct pagerlst dev_pager_object_list; 72 /* protect list manipulation */ 73 static struct mtx dev_pager_mtx; 74 75 struct pagerops devicepagerops = { 76 .pgo_init = dev_pager_init, 77 .pgo_alloc = dev_pager_alloc, 78 .pgo_dealloc = dev_pager_dealloc, 79 .pgo_getpages = dev_pager_getpages, 80 .pgo_putpages = dev_pager_putpages, 81 .pgo_haspage = dev_pager_haspage, 82 }; 83 84 struct pagerops mgtdevicepagerops = { 85 .pgo_alloc = dev_pager_alloc, 86 .pgo_dealloc = dev_pager_dealloc, 87 .pgo_getpages = dev_pager_getpages, 88 .pgo_putpages = dev_pager_putpages, 89 .pgo_haspage = dev_pager_haspage, 90 .pgo_populate = dev_pager_populate, 91 }; 92 93 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, 94 vm_ooffset_t foff, struct ucred *cred, u_short *color); 95 static void old_dev_pager_dtor(void *handle); 96 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, 97 int prot, vm_page_t *mres); 98 99 static struct cdev_pager_ops old_dev_pager_ops = { 100 .cdev_pg_ctor = old_dev_pager_ctor, 101 .cdev_pg_dtor = old_dev_pager_dtor, 102 .cdev_pg_fault = old_dev_pager_fault 103 }; 104 105 static void 106 dev_pager_init(void) 107 { 108 109 TAILQ_INIT(&dev_pager_object_list); 110 mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF); 111 } 112 113 vm_object_t 114 cdev_pager_lookup(void *handle) 115 { 116 vm_object_t object; 117 118 mtx_lock(&dev_pager_mtx); 119 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 120 mtx_unlock(&dev_pager_mtx); 121 return (object); 122 } 123 124 vm_object_t 125 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops, 126 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred) 127 { 128 vm_object_t object, object1; 129 vm_pindex_t pindex; 130 u_short color; 131 132 if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE) 133 return (NULL); 134 KASSERT(tp == OBJT_MGTDEVICE || ops->cdev_pg_populate == NULL, 135 ("populate on unmanaged device pager")); 136 137 /* 138 * Offset should be page aligned. 139 */ 140 if (foff & PAGE_MASK) 141 return (NULL); 142 143 /* 144 * Treat the mmap(2) file offset as an unsigned value for a 145 * device mapping. This, in effect, allows a user to pass all 146 * possible off_t values as the mapping cookie to the driver. At 147 * this point, we know that both foff and size are a multiple 148 * of the page size. Do a check to avoid wrap. 149 */ 150 size = round_page(size); 151 pindex = UOFF_TO_IDX(foff) + UOFF_TO_IDX(size); 152 if (pindex > OBJ_MAX_SIZE || pindex < UOFF_TO_IDX(foff) || 153 pindex < UOFF_TO_IDX(size)) 154 return (NULL); 155 156 if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0) 157 return (NULL); 158 mtx_lock(&dev_pager_mtx); 159 160 /* 161 * Look up pager, creating as necessary. 162 */ 163 object1 = NULL; 164 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 165 if (object == NULL) { 166 /* 167 * Allocate object and associate it with the pager. Initialize 168 * the object's pg_color based upon the physical address of the 169 * device's memory. 170 */ 171 mtx_unlock(&dev_pager_mtx); 172 object1 = vm_object_allocate(tp, pindex); 173 object1->flags |= OBJ_COLORED; 174 object1->pg_color = color; 175 object1->handle = handle; 176 object1->un_pager.devp.ops = ops; 177 object1->un_pager.devp.dev = handle; 178 TAILQ_INIT(&object1->un_pager.devp.devp_pglist); 179 mtx_lock(&dev_pager_mtx); 180 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 181 if (object != NULL) { 182 /* 183 * We raced with other thread while allocating object. 184 */ 185 if (pindex > object->size) 186 object->size = pindex; 187 KASSERT(object->type == tp, 188 ("Inconsistent device pager type %p %d", 189 object, tp)); 190 KASSERT(object->un_pager.devp.ops == ops, 191 ("Inconsistent devops %p %p", object, ops)); 192 } else { 193 object = object1; 194 object1 = NULL; 195 object->handle = handle; 196 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, 197 pager_object_list); 198 if (ops->cdev_pg_populate != NULL) 199 vm_object_set_flag(object, OBJ_POPULATE); 200 } 201 } else { 202 if (pindex > object->size) 203 object->size = pindex; 204 KASSERT(object->type == tp, 205 ("Inconsistent device pager type %p %d", object, tp)); 206 } 207 mtx_unlock(&dev_pager_mtx); 208 if (object1 != NULL) { 209 object1->handle = object1; 210 mtx_lock(&dev_pager_mtx); 211 TAILQ_INSERT_TAIL(&dev_pager_object_list, object1, 212 pager_object_list); 213 mtx_unlock(&dev_pager_mtx); 214 vm_object_deallocate(object1); 215 } 216 return (object); 217 } 218 219 static vm_object_t 220 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 221 vm_ooffset_t foff, struct ucred *cred) 222 { 223 224 return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops, 225 size, prot, foff, cred)); 226 } 227 228 void 229 cdev_pager_free_page(vm_object_t object, vm_page_t m) 230 { 231 232 VM_OBJECT_ASSERT_WLOCKED(object); 233 if (object->type == OBJT_MGTDEVICE) { 234 KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m)); 235 pmap_remove_all(m); 236 vm_page_lock(m); 237 vm_page_remove(m); 238 vm_page_unlock(m); 239 } else if (object->type == OBJT_DEVICE) 240 dev_pager_free_page(object, m); 241 } 242 243 static void 244 dev_pager_free_page(vm_object_t object, vm_page_t m) 245 { 246 247 VM_OBJECT_ASSERT_WLOCKED(object); 248 KASSERT((object->type == OBJT_DEVICE && 249 (m->oflags & VPO_UNMANAGED) != 0), 250 ("Managed device or page obj %p m %p", object, m)); 251 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, plinks.q); 252 vm_page_putfake(m); 253 } 254 255 static void 256 dev_pager_dealloc(vm_object_t object) 257 { 258 vm_page_t m; 259 260 VM_OBJECT_WUNLOCK(object); 261 object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev); 262 263 mtx_lock(&dev_pager_mtx); 264 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 265 mtx_unlock(&dev_pager_mtx); 266 VM_OBJECT_WLOCK(object); 267 268 if (object->type == OBJT_DEVICE) { 269 /* 270 * Free up our fake pages. 271 */ 272 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) 273 != NULL) 274 dev_pager_free_page(object, m); 275 } 276 object->handle = NULL; 277 object->type = OBJT_DEAD; 278 } 279 280 static int 281 dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int *rbehind, 282 int *rahead) 283 { 284 int error; 285 286 /* Since our haspage reports zero after/before, the count is 1. */ 287 KASSERT(count == 1, ("%s: count %d", __func__, count)); 288 VM_OBJECT_ASSERT_WLOCKED(object); 289 if (object->un_pager.devp.ops->cdev_pg_fault == NULL) 290 return (VM_PAGER_FAIL); 291 error = object->un_pager.devp.ops->cdev_pg_fault(object, 292 IDX_TO_OFF(ma[0]->pindex), PROT_READ, &ma[0]); 293 294 VM_OBJECT_ASSERT_WLOCKED(object); 295 296 if (error == VM_PAGER_OK) { 297 KASSERT((object->type == OBJT_DEVICE && 298 (ma[0]->oflags & VPO_UNMANAGED) != 0) || 299 (object->type == OBJT_MGTDEVICE && 300 (ma[0]->oflags & VPO_UNMANAGED) == 0), 301 ("Wrong page type %p %p", ma[0], object)); 302 if (object->type == OBJT_DEVICE) { 303 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, 304 ma[0], plinks.q); 305 } 306 if (rbehind) 307 *rbehind = 0; 308 if (rahead) 309 *rahead = 0; 310 } 311 312 return (error); 313 } 314 315 static int 316 dev_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type, 317 vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last) 318 { 319 320 VM_OBJECT_ASSERT_WLOCKED(object); 321 if (object->un_pager.devp.ops->cdev_pg_populate == NULL) 322 return (VM_PAGER_FAIL); 323 return (object->un_pager.devp.ops->cdev_pg_populate(object, pidx, 324 fault_type, max_prot, first, last)); 325 } 326 327 static int 328 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot, 329 vm_page_t *mres) 330 { 331 vm_paddr_t paddr; 332 vm_page_t m_paddr, page; 333 struct cdev *dev; 334 struct cdevsw *csw; 335 struct file *fpop; 336 struct thread *td; 337 vm_memattr_t memattr, memattr1; 338 int ref, ret; 339 340 memattr = object->memattr; 341 342 VM_OBJECT_WUNLOCK(object); 343 344 dev = object->handle; 345 csw = dev_refthread(dev, &ref); 346 if (csw == NULL) { 347 VM_OBJECT_WLOCK(object); 348 return (VM_PAGER_FAIL); 349 } 350 td = curthread; 351 fpop = td->td_fpop; 352 td->td_fpop = NULL; 353 ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr); 354 td->td_fpop = fpop; 355 dev_relthread(dev, ref); 356 if (ret != 0) { 357 printf( 358 "WARNING: dev_pager_getpage: map function returns error %d", ret); 359 VM_OBJECT_WLOCK(object); 360 return (VM_PAGER_FAIL); 361 } 362 363 /* If "paddr" is a real page, perform a sanity check on "memattr". */ 364 if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL && 365 (memattr1 = pmap_page_get_memattr(m_paddr)) != memattr) { 366 /* 367 * For the /dev/mem d_mmap routine to return the 368 * correct memattr, pmap_page_get_memattr() needs to 369 * be called, which we do there. 370 */ 371 if ((csw->d_flags & D_MEM) == 0) { 372 printf("WARNING: Device driver %s has set " 373 "\"memattr\" inconsistently (drv %u pmap %u).\n", 374 csw->d_name, memattr, memattr1); 375 } 376 memattr = memattr1; 377 } 378 if (((*mres)->flags & PG_FICTITIOUS) != 0) { 379 /* 380 * If the passed in result page is a fake page, update it with 381 * the new physical address. 382 */ 383 page = *mres; 384 VM_OBJECT_WLOCK(object); 385 vm_page_updatefake(page, paddr, memattr); 386 } else { 387 /* 388 * Replace the passed in reqpage page with our own fake page and 389 * free up the all of the original pages. 390 */ 391 page = vm_page_getfake(paddr, memattr); 392 VM_OBJECT_WLOCK(object); 393 vm_page_replace_checked(page, object, (*mres)->pindex, *mres); 394 vm_page_lock(*mres); 395 vm_page_free(*mres); 396 vm_page_unlock(*mres); 397 *mres = page; 398 } 399 page->valid = VM_PAGE_BITS_ALL; 400 return (VM_PAGER_OK); 401 } 402 403 static void 404 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags, 405 int *rtvals) 406 { 407 408 panic("dev_pager_putpage called"); 409 } 410 411 static boolean_t 412 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 413 int *after) 414 { 415 416 if (before != NULL) 417 *before = 0; 418 if (after != NULL) 419 *after = 0; 420 return (TRUE); 421 } 422 423 static int 424 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, 425 vm_ooffset_t foff, struct ucred *cred, u_short *color) 426 { 427 struct cdev *dev; 428 struct cdevsw *csw; 429 vm_memattr_t dummy; 430 vm_ooffset_t off; 431 vm_paddr_t paddr; 432 unsigned int npages; 433 int ref; 434 435 /* 436 * Make sure this device can be mapped. 437 */ 438 dev = handle; 439 csw = dev_refthread(dev, &ref); 440 if (csw == NULL) 441 return (ENXIO); 442 443 /* 444 * Check that the specified range of the device allows the desired 445 * protection. 446 * 447 * XXX assumes VM_PROT_* == PROT_* 448 */ 449 npages = OFF_TO_IDX(size); 450 paddr = 0; /* Make paddr initialized for the case of size == 0. */ 451 for (off = foff; npages--; off += PAGE_SIZE) { 452 if (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) { 453 dev_relthread(dev, ref); 454 return (EINVAL); 455 } 456 } 457 458 dev_ref(dev); 459 dev_relthread(dev, ref); 460 *color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE); 461 return (0); 462 } 463 464 static void 465 old_dev_pager_dtor(void *handle) 466 { 467 468 dev_rel(handle); 469 }
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