1 /* 2 * (MPSAFE) 3 * 4 * Copyright (c) 1990 University of Utah. 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93 37 * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $ 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/conf.h> 44 #include <sys/mman.h> 45 #include <sys/device.h> 46 #include <sys/queue.h> 47 #include <sys/malloc.h> 48 #include <sys/thread2.h> 49 #include <sys/mutex2.h> 50 51 #include <vm/vm.h> 52 #include <vm/vm_object.h> 53 #include <vm/vm_page.h> 54 #include <vm/vm_pager.h> 55 #include <vm/vm_zone.h> 56 #include <vm/vm_page2.h> 57 58 static void dev_pager_dealloc (vm_object_t); 59 static int dev_pager_getpage (vm_object_t, vm_page_t *, int); 60 static void dev_pager_putpages (vm_object_t, vm_page_t *, int, int, int *); 61 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t); 62 63 /* list of device pager objects */ 64 static TAILQ_HEAD(, vm_page) dev_freepages_list = 65 TAILQ_HEAD_INITIALIZER(dev_freepages_list); 66 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages", 67 "Device mapped pages"); 68 69 static vm_page_t dev_pager_getfake (vm_paddr_t, int); 70 static void dev_pager_putfake (vm_page_t); 71 72 struct pagerops devicepagerops = { 73 dev_pager_dealloc, 74 dev_pager_getpage, 75 dev_pager_putpages, 76 dev_pager_haspage 77 }; 78 79 /* list of device pager objects */ 80 static struct pagerlst dev_pager_object_list = 81 TAILQ_HEAD_INITIALIZER(dev_pager_object_list); 82 /* protect list manipulation */ 83 static struct mtx dev_pager_mtx = MTX_INITIALIZER("devpgr"); 84 85 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, 86 vm_ooffset_t foff, struct ucred *cred, u_short *pg_color); 87 static void old_dev_pager_dtor(void *handle); 88 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, 89 int prot, vm_page_t *mres); 90 91 static struct cdev_pager_ops old_dev_pager_ops = { 92 .cdev_pg_ctor = old_dev_pager_ctor, 93 .cdev_pg_dtor = old_dev_pager_dtor, 94 .cdev_pg_fault = old_dev_pager_fault 95 }; 96 97 vm_object_t 98 cdev_pager_lookup(void *handle) 99 { 100 vm_object_t object; 101 102 mtx_lock(&dev_pager_mtx); 103 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 104 mtx_unlock(&dev_pager_mtx); 105 106 return (object); 107 } 108 109 vm_object_t 110 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops, 111 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred) 112 { 113 cdev_t dev; 114 vm_object_t object; 115 u_short color; 116 117 /* 118 * Offset should be page aligned. 119 */ 120 if (foff & PAGE_MASK) 121 return (NULL); 122 123 size = round_page64(size); 124 125 if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0) 126 return (NULL); 127 128 /* 129 * Look up pager, creating as necessary. 130 */ 131 mtx_lock(&dev_pager_mtx); 132 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 133 if (object == NULL) { 134 /* 135 * Allocate object and associate it with the pager. 136 */ 137 object = vm_object_allocate_hold(tp, 138 OFF_TO_IDX(foff + size)); 139 object->handle = handle; 140 object->un_pager.devp.ops = ops; 141 object->un_pager.devp.dev = handle; 142 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 143 144 /* 145 * handle is only a device for old_dev_pager_ctor. 146 */ 147 if (ops->cdev_pg_ctor == old_dev_pager_ctor) { 148 dev = handle; 149 dev->si_object = object; 150 } 151 152 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, 153 pager_object_list); 154 155 vm_object_drop(object); 156 } else { 157 /* 158 * Gain a reference to the object. 159 */ 160 vm_object_hold(object); 161 vm_object_reference_locked(object); 162 if (OFF_TO_IDX(foff + size) > object->size) 163 object->size = OFF_TO_IDX(foff + size); 164 vm_object_drop(object); 165 } 166 mtx_unlock(&dev_pager_mtx); 167 168 return (object); 169 } 170 171 /* 172 * No requirements. 173 */ 174 vm_object_t 175 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff) 176 { 177 return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops, 178 size, prot, foff, NULL)); 179 } 180 181 /* 182 * Caller must hold object lock. 183 */ 184 void 185 cdev_pager_free_page(vm_object_t object, vm_page_t m) 186 { 187 if (object->type == OBJT_MGTDEVICE) { 188 KKASSERT((m->flags & PG_FICTITIOUS) != 0); 189 pmap_page_protect(m, VM_PROT_NONE); 190 vm_page_remove(m); 191 vm_page_wakeup(m); 192 } else if (object->type == OBJT_DEVICE) { 193 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 194 dev_pager_putfake(m); 195 } 196 } 197 198 /* 199 * No requirements. 200 */ 201 static void 202 dev_pager_dealloc(vm_object_t object) 203 { 204 vm_page_t m; 205 206 /* 207 * NOTE: Callback may recurse into the device pager so do not 208 * obtain dev_pager_mtx until after it returns. 209 * 210 * The mutex should only be needed when manipulating the list. 211 */ 212 object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev); 213 214 mtx_lock(&dev_pager_mtx); 215 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 216 mtx_unlock(&dev_pager_mtx); 217 218 if (object->type == OBJT_DEVICE) { 219 /* 220 * Free up our fake pages. 221 */ 222 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 223 NULL) { 224 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, 225 m, pageq); 226 dev_pager_putfake(m); 227 } 228 } 229 } 230 231 /* 232 * No requirements. 233 * 234 * WARNING! Do not obtain dev_pager_mtx here, doing so will cause a 235 * deadlock in DRMs VM paging code. 236 */ 237 static int 238 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 239 { 240 vm_page_t page; 241 int error; 242 243 page = *mpp; 244 245 error = object->un_pager.devp.ops->cdev_pg_fault( 246 object, IDX_TO_OFF(page->pindex), 247 PROT_READ, mpp); 248 249 return (error); 250 } 251 252 /* 253 * No requirements. 254 */ 255 static void 256 dev_pager_putpages(vm_object_t object, vm_page_t *m, 257 int count, int sync, int *rtvals) 258 { 259 panic("dev_pager_putpage called"); 260 } 261 262 /* 263 * No requirements. 264 */ 265 static boolean_t 266 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex) 267 { 268 return (TRUE); 269 } 270 271 /* 272 * The caller does not need to hold dev_pager_mtx() but caller must ensure 273 * no page-use collision. 274 */ 275 static vm_page_t 276 dev_pager_getfake(vm_paddr_t paddr, int pat_mode) 277 { 278 vm_page_t m; 279 280 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO); 281 282 pmap_page_init(m); 283 284 m->flags = PG_BUSY | PG_FICTITIOUS; 285 m->valid = VM_PAGE_BITS_ALL; 286 m->dirty = 0; 287 m->busy = 0; 288 m->queue = PQ_NONE; 289 m->object = NULL; 290 291 m->wire_count = 1; 292 m->hold_count = 0; 293 m->phys_addr = paddr; 294 m->pat_mode = pat_mode; 295 296 spin_init(&m->spin, "dev_page"); 297 298 return (m); 299 } 300 301 /* 302 * The caller does not need to hold dev_pager_mtx() but caller must ensure 303 * no page-use collision within the object. 304 */ 305 static void 306 dev_pager_putfake(vm_page_t m) 307 { 308 if (!(m->flags & PG_FICTITIOUS)) 309 panic("dev_pager_putfake: bad page"); 310 KKASSERT(m->object == NULL); 311 KKASSERT(m->hold_count == 0); 312 kfree(m, M_FICTITIOUS_PAGES); 313 } 314 315 static int 316 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, 317 vm_ooffset_t foff, struct ucred *cred, u_short *color) 318 { 319 unsigned int npages; 320 vm_offset_t off; 321 cdev_t dev; 322 323 dev = handle; 324 325 /* 326 * Check that the specified range of the device allows the desired 327 * protection. 328 * 329 * XXX assumes VM_PROT_* == PROT_* 330 */ 331 npages = OFF_TO_IDX(size); 332 for (off = foff; npages--; off += PAGE_SIZE) { 333 if (dev_dmmap(dev, off, (int)prot, NULL) == -1) 334 return (EINVAL); 335 } 336 337 return (0); 338 } 339 340 static void old_dev_pager_dtor(void *handle) 341 { 342 cdev_t dev; 343 344 dev = handle; 345 if (dev != NULL) { 346 KKASSERT(dev->si_object); 347 dev->si_object = NULL; 348 } 349 } 350 351 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, 352 int prot, vm_page_t *mres) 353 { 354 vm_paddr_t paddr; 355 vm_page_t page; 356 vm_offset_t pidx = OFF_TO_IDX(offset); 357 cdev_t dev; 358 359 page = *mres; 360 dev = object->handle; 361 362 paddr = pmap_phys_address(dev_dmmap(dev, offset, prot, NULL)); 363 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 364 KKASSERT(object->type == OBJT_DEVICE); 365 366 if (page->flags & PG_FICTITIOUS) { 367 /* 368 * If the passed in reqpage page is already a fake page, 369 * update it with the new physical address. 370 */ 371 page->phys_addr = paddr; 372 page->valid = VM_PAGE_BITS_ALL; 373 } else { 374 /* 375 * Replace the passed in reqpage page with our own fake page 376 * and free up all the original pages. Object lock must be 377 * held when manipulating devp_pglist and inserting the 378 * page. 379 */ 380 page = dev_pager_getfake(paddr, object->memattr); 381 vm_object_hold(object); 382 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, 383 page, pageq); 384 vm_page_free(*mres); 385 if (vm_page_insert(page, object, pidx) == FALSE) { 386 panic("dev_pager_getpage: page (%p,%016jx) exists", 387 object, (uintmax_t)pidx); 388 } 389 vm_object_drop(object); 390 } 391 392 return (VM_PAGER_OK); 393 } 394 395