device_pager.c revision 171779
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: head/sys/vm/device_pager.c 171779 2007-08-07 15:36:25Z kib $"); 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/sx.h> 48 49#include <vm/vm.h> 50#include <vm/vm_object.h> 51#include <vm/vm_page.h> 52#include <vm/vm_pager.h> 53#include <vm/uma.h> 54 55static void dev_pager_init(void); 56static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 57 vm_ooffset_t); 58static void dev_pager_dealloc(vm_object_t); 59static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int); 60static void dev_pager_putpages(vm_object_t, vm_page_t *, int, 61 boolean_t, int *); 62static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, 63 int *); 64 65/* list of device pager objects */ 66static struct pagerlst dev_pager_object_list; 67/* protect list manipulation */ 68static struct mtx dev_pager_mtx; 69 70 71static uma_zone_t fakepg_zone; 72 73static vm_page_t dev_pager_getfake(vm_paddr_t); 74static void dev_pager_putfake(vm_page_t); 75static void dev_pager_updatefake(vm_page_t, vm_paddr_t); 76 77struct pagerops devicepagerops = { 78 .pgo_init = dev_pager_init, 79 .pgo_alloc = dev_pager_alloc, 80 .pgo_dealloc = dev_pager_dealloc, 81 .pgo_getpages = dev_pager_getpages, 82 .pgo_putpages = dev_pager_putpages, 83 .pgo_haspage = dev_pager_haspage, 84}; 85 86static void 87dev_pager_init() 88{ 89 TAILQ_INIT(&dev_pager_object_list); 90 mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF); 91 fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page), 92 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 93 UMA_ZONE_NOFREE|UMA_ZONE_VM); 94} 95 96/* 97 * MPSAFE 98 */ 99static vm_object_t 100dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff) 101{ 102 struct cdev *dev; 103 vm_object_t object, object1; 104 vm_pindex_t pindex; 105 unsigned int npages; 106 vm_paddr_t paddr; 107 vm_offset_t off; 108 struct cdevsw *csw; 109 110 /* 111 * Offset should be page aligned. 112 */ 113 if (foff & PAGE_MASK) 114 return (NULL); 115 116 size = round_page(size); 117 pindex = OFF_TO_IDX(foff + size); 118 119 /* 120 * Make sure this device can be mapped. 121 */ 122 dev = handle; 123 csw = dev_refthread(dev); 124 if (csw == NULL) 125 return (NULL); 126 127 /* 128 * Check that the specified range of the device allows the desired 129 * protection. 130 * 131 * XXX assumes VM_PROT_* == PROT_* 132 */ 133 npages = OFF_TO_IDX(size); 134 for (off = foff; npages--; off += PAGE_SIZE) 135 if ((*csw->d_mmap)(dev, off, &paddr, (int)prot) != 0) { 136 dev_relthread(dev); 137 return (NULL); 138 } 139 140 /* 141 * Lock to prevent object creation race condition. 142 */ 143 mtx_lock(&dev_pager_mtx); 144 145 /* 146 * Look up pager, creating as necessary. 147 */ 148 object1 = NULL; 149 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 150 if (object == NULL) { 151 /* 152 * Allocate object and associate it with the pager. 153 */ 154 mtx_unlock(&dev_pager_mtx); 155 object1 = vm_object_allocate(OBJT_DEVICE, pindex); 156 mtx_lock(&dev_pager_mtx); 157 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 158 if (object != NULL) { 159 /* 160 * We raced with other thread while allocating object. 161 */ 162 if (pindex > object->size) 163 object->size = pindex; 164 } else { 165 object = object1; 166 object1 = NULL; 167 object->handle = handle; 168 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 169 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, 170 pager_object_list); 171 } 172 } else { 173 if (pindex > object->size) 174 object->size = pindex; 175 } 176 mtx_unlock(&dev_pager_mtx); 177 dev_relthread(dev); 178 vm_object_deallocate(object1); 179 return (object); 180} 181 182static void 183dev_pager_dealloc(object) 184 vm_object_t object; 185{ 186 vm_page_t m; 187 188 VM_OBJECT_UNLOCK(object); 189 mtx_lock(&dev_pager_mtx); 190 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 191 mtx_unlock(&dev_pager_mtx); 192 VM_OBJECT_LOCK(object); 193 /* 194 * Free up our fake pages. 195 */ 196 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 197 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 198 dev_pager_putfake(m); 199 } 200} 201 202static int 203dev_pager_getpages(object, m, count, reqpage) 204 vm_object_t object; 205 vm_page_t *m; 206 int count; 207 int reqpage; 208{ 209 vm_pindex_t offset; 210 vm_paddr_t paddr; 211 vm_page_t page; 212 struct cdev *dev; 213 int i, ret; 214 int prot; 215 struct cdevsw *csw; 216 217 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 218 dev = object->handle; 219 offset = m[reqpage]->pindex; 220 VM_OBJECT_UNLOCK(object); 221 csw = dev_refthread(dev); 222 if (csw == NULL) 223 panic("dev_pager_getpage: no cdevsw"); 224 prot = PROT_READ; /* XXX should pass in? */ 225 226 ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot); 227 KASSERT(ret == 0, ("dev_pager_getpage: map function returns error")); 228 dev_relthread(dev); 229 230 if ((m[reqpage]->flags & PG_FICTITIOUS) != 0) { 231 /* 232 * If the passed in reqpage page is a fake page, update it with 233 * the new physical address. 234 */ 235 VM_OBJECT_LOCK(object); 236 dev_pager_updatefake(m[reqpage], paddr); 237 if (count > 1) { 238 vm_page_lock_queues(); 239 for (i = 0; i < count; i++) { 240 if (i != reqpage) 241 vm_page_free(m[i]); 242 } 243 vm_page_unlock_queues(); 244 } 245 } else { 246 /* 247 * Replace the passed in reqpage page with our own fake page and 248 * free up the all of the original pages. 249 */ 250 page = dev_pager_getfake(paddr); 251 VM_OBJECT_LOCK(object); 252 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 253 vm_page_lock_queues(); 254 for (i = 0; i < count; i++) 255 vm_page_free(m[i]); 256 vm_page_unlock_queues(); 257 vm_page_insert(page, object, offset); 258 m[reqpage] = page; 259 } 260 261 return (VM_PAGER_OK); 262} 263 264static void 265dev_pager_putpages(object, m, count, sync, rtvals) 266 vm_object_t object; 267 vm_page_t *m; 268 int count; 269 boolean_t sync; 270 int *rtvals; 271{ 272 panic("dev_pager_putpage called"); 273} 274 275static boolean_t 276dev_pager_haspage(object, pindex, before, after) 277 vm_object_t object; 278 vm_pindex_t pindex; 279 int *before; 280 int *after; 281{ 282 if (before != NULL) 283 *before = 0; 284 if (after != NULL) 285 *after = 0; 286 return (TRUE); 287} 288 289/* 290 * Instantiate a fictitious page. Unlike physical memory pages, only 291 * the machine-independent fields must be initialized. 292 */ 293static vm_page_t 294dev_pager_getfake(paddr) 295 vm_paddr_t paddr; 296{ 297 vm_page_t m; 298 299 m = uma_zalloc(fakepg_zone, M_WAITOK); 300 301 m->flags = PG_FICTITIOUS; 302 m->oflags = VPO_BUSY; 303 m->valid = VM_PAGE_BITS_ALL; 304 m->dirty = 0; 305 m->busy = 0; 306 m->queue = PQ_NONE; 307 m->object = NULL; 308 309 m->wire_count = 1; 310 m->hold_count = 0; 311 m->phys_addr = paddr; 312 313 return (m); 314} 315 316static void 317dev_pager_putfake(m) 318 vm_page_t m; 319{ 320 if (!(m->flags & PG_FICTITIOUS)) 321 panic("dev_pager_putfake: bad page"); 322 uma_zfree(fakepg_zone, m); 323} 324 325static void 326dev_pager_updatefake(m, paddr) 327 vm_page_t m; 328 vm_paddr_t paddr; 329{ 330 if (!(m->flags & PG_FICTITIOUS)) 331 panic("dev_pager_updatefake: bad page"); 332 m->phys_addr = paddr; 333 m->valid = VM_PAGE_BITS_ALL; 334} 335