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 mtx_lock(&dev_pager_mtx); 102 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 103 mtx_unlock(&dev_pager_mtx); 104 return (object); 105 } 106 107 vm_object_t 108 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops, 109 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred) 110 { 111 cdev_t dev; 112 vm_object_t object; 113 u_short color; 114 115 /* 116 * Offset should be page aligned. 117 */ 118 if (foff & PAGE_MASK) 119 return (NULL); 120 121 size = round_page64(size); 122 123 if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0) 124 return (NULL); 125 126 /* 127 * Look up pager, creating as necessary. 128 */ 129 mtx_lock(&dev_pager_mtx); 130 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 131 if (object == NULL) { 132 /* 133 * Allocate object and associate it with the pager. 134 */ 135 object = vm_object_allocate_hold(tp, 136 OFF_TO_IDX(foff + size)); 137 object->handle = handle; 138 object->un_pager.devp.ops = ops; 139 object->un_pager.devp.dev = handle; 140 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 141 142 /* 143 * handle is only a device for old_dev_pager_ctor. 144 */ 145 if (ops->cdev_pg_ctor == old_dev_pager_ctor) { 146 dev = handle; 147 dev->si_object = object; 148 } 149 150 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, 151 pager_object_list); 152 153 vm_object_drop(object); 154 } else { 155 /* 156 * Gain a reference to the object. 157 */ 158 vm_object_hold(object); 159 vm_object_reference_locked(object); 160 if (OFF_TO_IDX(foff + size) > object->size) 161 object->size = OFF_TO_IDX(foff + size); 162 vm_object_drop(object); 163 } 164 mtx_unlock(&dev_pager_mtx); 165 166 return (object); 167 } 168 169 /* 170 * No requirements. 171 */ 172 vm_object_t 173 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff) 174 { 175 return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops, 176 size, prot, foff, NULL)); 177 } 178 179 /* XXX */ 180 void 181 cdev_pager_free_page(vm_object_t object, vm_page_t m) 182 { 183 if (object->type == OBJT_MGTDEVICE) { 184 KKASSERT((m->flags & PG_FICTITIOUS) != 0); 185 pmap_page_protect(m, VM_PROT_NONE); 186 vm_page_remove(m); 187 vm_page_wakeup(m); 188 } else if (object->type == OBJT_DEVICE) { 189 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 190 dev_pager_putfake(m); 191 } 192 } 193 194 /* 195 * No requirements. 196 */ 197 static void 198 dev_pager_dealloc(vm_object_t object) 199 { 200 vm_page_t m; 201 202 mtx_lock(&dev_pager_mtx); 203 object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev); 204 205 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 206 207 if (object->type == OBJT_DEVICE) { 208 /* 209 * Free up our fake pages. 210 */ 211 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 212 NULL) { 213 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, 214 m, pageq); 215 dev_pager_putfake(m); 216 } 217 } 218 mtx_unlock(&dev_pager_mtx); 219 } 220 221 /* 222 * No requirements. 223 * 224 * WARNING! Do not obtain dev_pager_mtx here, doing so will cause a 225 * deadlock in DRMs VM paging code. 226 */ 227 static int 228 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 229 { 230 vm_page_t page; 231 int error; 232 233 page = *mpp; 234 235 error = object->un_pager.devp.ops->cdev_pg_fault( 236 object, IDX_TO_OFF(page->pindex), 237 PROT_READ, mpp); 238 239 return (error); 240 } 241 242 /* 243 * No requirements. 244 */ 245 static void 246 dev_pager_putpages(vm_object_t object, vm_page_t *m, 247 int count, int sync, int *rtvals) 248 { 249 panic("dev_pager_putpage called"); 250 } 251 252 /* 253 * No requirements. 254 */ 255 static boolean_t 256 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex) 257 { 258 return (TRUE); 259 } 260 261 /* 262 * The caller must hold dev_pager_mtx 263 */ 264 static vm_page_t 265 dev_pager_getfake(vm_paddr_t paddr, int pat_mode) 266 { 267 vm_page_t m; 268 269 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO); 270 271 pmap_page_init(m); 272 273 m->flags = PG_BUSY | PG_FICTITIOUS; 274 m->valid = VM_PAGE_BITS_ALL; 275 m->dirty = 0; 276 m->busy = 0; 277 m->queue = PQ_NONE; 278 m->object = NULL; 279 280 m->wire_count = 1; 281 m->hold_count = 0; 282 m->phys_addr = paddr; 283 m->pat_mode = pat_mode; 284 285 return (m); 286 } 287 288 /* 289 * Synthesized VM pages must be structurally stable for lockless lookups to 290 * work properly. 291 * 292 * The caller must hold dev_pager_mtx 293 */ 294 static void 295 dev_pager_putfake(vm_page_t m) 296 { 297 if (!(m->flags & PG_FICTITIOUS)) 298 panic("dev_pager_putfake: bad page"); 299 KKASSERT(m->object == NULL); 300 KKASSERT(m->hold_count == 0); 301 kfree(m, M_FICTITIOUS_PAGES); 302 } 303 304 static int 305 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, 306 vm_ooffset_t foff, struct ucred *cred, u_short *color) 307 { 308 unsigned int npages; 309 vm_offset_t off; 310 cdev_t dev; 311 312 dev = handle; 313 314 /* 315 * Check that the specified range of the device allows the desired 316 * protection. 317 * 318 * XXX assumes VM_PROT_* == PROT_* 319 */ 320 npages = OFF_TO_IDX(size); 321 for (off = foff; npages--; off += PAGE_SIZE) { 322 if (dev_dmmap(dev, off, (int)prot, NULL) == -1) 323 return (EINVAL); 324 } 325 326 return (0); 327 } 328 329 static void old_dev_pager_dtor(void *handle) 330 { 331 cdev_t dev; 332 333 dev = handle; 334 if (dev != NULL) { 335 KKASSERT(dev->si_object); 336 dev->si_object = NULL; 337 } 338 } 339 340 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, 341 int prot, vm_page_t *mres) 342 { 343 vm_paddr_t paddr; 344 vm_page_t page; 345 vm_offset_t pidx = OFF_TO_IDX(offset); 346 cdev_t dev; 347 348 page = *mres; 349 dev = object->handle; 350 351 paddr = pmap_phys_address( 352 dev_dmmap(dev, offset, prot, NULL)); 353 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 354 KKASSERT(object->type == OBJT_DEVICE); 355 356 if (page->flags & PG_FICTITIOUS) { 357 /* 358 * If the passed in reqpage page is already a fake page, 359 * update it with the new physical address. 360 */ 361 page->phys_addr = paddr; 362 page->valid = VM_PAGE_BITS_ALL; 363 } else { 364 /* 365 * Replace the passed in reqpage page with our own fake page 366 * and free up all the original pages. 367 */ 368 page = dev_pager_getfake(paddr, object->memattr); 369 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, 370 page, pageq); 371 vm_object_hold(object); 372 vm_page_free(*mres); 373 if (vm_page_insert(page, object, pidx) == FALSE) { 374 panic("dev_pager_getpage: page (%p,%016jx) exists", 375 object, (uintmax_t)pidx); 376 } 377 vm_object_drop(object); 378 } 379 380 return (VM_PAGER_OK); 381 } 382 383