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; 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 dev = handle; 115 116 /* 117 * Offset should be page aligned. 118 */ 119 if (foff & PAGE_MASK) 120 return (NULL); 121 122 size = round_page64(size); 123 124 if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0) 125 return (NULL); 126 127 /* 128 * Look up pager, creating as necessary. 129 */ 130 mtx_lock(&dev_pager_mtx); 131 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 132 if (object == NULL) { 133 /* 134 * Allocate object and associate it with the pager. 135 */ 136 object = vm_object_allocate_hold(tp, 137 OFF_TO_IDX(foff + size)); 138 object->handle = handle; 139 object->un_pager.devp.ops = ops; 140 object->un_pager.devp.dev = handle; 141 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 142 dev->si_object = object; 143 144 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, 145 pager_object_list); 146 147 vm_object_drop(object); 148 } else { 149 /* 150 * Gain a reference to the object. 151 */ 152 vm_object_hold(object); 153 vm_object_reference_locked(object); 154 if (OFF_TO_IDX(foff + size) > object->size) 155 object->size = OFF_TO_IDX(foff + size); 156 vm_object_drop(object); 157 } 158 mtx_unlock(&dev_pager_mtx); 159 160 return (object); 161 } 162 163 /* 164 * No requirements. 165 */ 166 vm_object_t 167 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff) 168 { 169 return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops, 170 size, prot, foff, NULL)); 171 } 172 173 /* XXX */ 174 void 175 cdev_pager_free_page(vm_object_t object, vm_page_t m) 176 { 177 if (object->type == OBJT_MGTDEVICE) { 178 KKASSERT((m->flags & PG_FICTITIOUS) != 0); 179 pmap_page_protect(m, VM_PROT_NONE); 180 vm_page_remove(m); 181 vm_page_wakeup(m); 182 } else if (object->type == OBJT_DEVICE) { 183 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 184 dev_pager_putfake(m); 185 } 186 } 187 188 /* 189 * No requirements. 190 */ 191 static void 192 dev_pager_dealloc(vm_object_t object) 193 { 194 vm_page_t m; 195 196 mtx_lock(&dev_pager_mtx); 197 object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev); 198 199 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 200 201 if (object->type == OBJT_DEVICE) { 202 /* 203 * Free up our fake pages. 204 */ 205 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 206 NULL) { 207 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, 208 m, pageq); 209 dev_pager_putfake(m); 210 } 211 } 212 mtx_unlock(&dev_pager_mtx); 213 } 214 215 /* 216 * No requirements. 217 */ 218 static int 219 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 220 { 221 vm_page_t page; 222 int error; 223 224 mtx_lock(&dev_pager_mtx); 225 226 page = *mpp; 227 228 error = object->un_pager.devp.ops->cdev_pg_fault(object, 229 IDX_TO_OFF(page->pindex), PROT_READ, mpp); 230 231 mtx_unlock(&dev_pager_mtx); 232 233 return (error); 234 } 235 236 /* 237 * No requirements. 238 */ 239 static void 240 dev_pager_putpages(vm_object_t object, vm_page_t *m, 241 int count, int sync, int *rtvals) 242 { 243 panic("dev_pager_putpage called"); 244 } 245 246 /* 247 * No requirements. 248 */ 249 static boolean_t 250 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex) 251 { 252 return (TRUE); 253 } 254 255 /* 256 * The caller must hold dev_pager_mtx 257 */ 258 static vm_page_t 259 dev_pager_getfake(vm_paddr_t paddr, int pat_mode) 260 { 261 vm_page_t m; 262 263 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO); 264 265 pmap_page_init(m); 266 267 m->flags = PG_BUSY | PG_FICTITIOUS; 268 m->valid = VM_PAGE_BITS_ALL; 269 m->dirty = 0; 270 m->busy = 0; 271 m->queue = PQ_NONE; 272 m->object = NULL; 273 274 m->wire_count = 1; 275 m->hold_count = 0; 276 m->phys_addr = paddr; 277 m->pat_mode = pat_mode; 278 279 return (m); 280 } 281 282 /* 283 * Synthesized VM pages must be structurally stable for lockless lookups to 284 * work properly. 285 * 286 * The caller must hold dev_pager_mtx 287 */ 288 static void 289 dev_pager_putfake(vm_page_t m) 290 { 291 if (!(m->flags & PG_FICTITIOUS)) 292 panic("dev_pager_putfake: bad page"); 293 KKASSERT(m->object == NULL); 294 KKASSERT(m->hold_count == 0); 295 kfree(m, M_FICTITIOUS_PAGES); 296 } 297 298 static int 299 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, 300 vm_ooffset_t foff, struct ucred *cred, u_short *color) 301 { 302 unsigned int npages; 303 vm_offset_t off; 304 cdev_t dev; 305 306 dev = handle; 307 308 /* 309 * Check that the specified range of the device allows the desired 310 * protection. 311 * 312 * XXX assumes VM_PROT_* == PROT_* 313 */ 314 npages = OFF_TO_IDX(size); 315 for (off = foff; npages--; off += PAGE_SIZE) { 316 if (dev_dmmap(dev, off, (int)prot, NULL) == -1) 317 return (EINVAL); 318 } 319 320 return (0); 321 } 322 323 static void old_dev_pager_dtor(void *handle) 324 { 325 cdev_t dev; 326 327 dev = handle; 328 if (dev != NULL) { 329 KKASSERT(dev->si_object); 330 dev->si_object = NULL; 331 } 332 } 333 334 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, 335 int prot, vm_page_t *mres) 336 { 337 vm_paddr_t paddr; 338 vm_page_t page; 339 vm_offset_t pidx = OFF_TO_IDX(offset); 340 cdev_t dev; 341 342 page = *mres; 343 dev = object->handle; 344 345 paddr = pmap_phys_address( 346 dev_dmmap(dev, offset, prot, NULL)); 347 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 348 KKASSERT(object->type == OBJT_DEVICE); 349 350 if (page->flags & PG_FICTITIOUS) { 351 /* 352 * If the passed in reqpage page is already a fake page, 353 * update it with the new physical address. 354 */ 355 page->phys_addr = paddr; 356 page->valid = VM_PAGE_BITS_ALL; 357 } else { 358 /* 359 * Replace the passed in reqpage page with our own fake page 360 * and free up all the original pages. 361 */ 362 page = dev_pager_getfake(paddr, object->memattr); 363 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, 364 page, pageq); 365 vm_object_hold(object); 366 vm_page_free(*mres); 367 if (vm_page_insert(page, object, pidx) == FALSE) { 368 panic("dev_pager_getpage: page (%p,%016jx) exists", 369 object, (uintmax_t)pidx); 370 } 371 vm_object_drop(object); 372 } 373 374 return (VM_PAGER_OK); 375 } 376 377