device_pager.c revision 183383
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 183383 2008-09-26 14:50:49Z 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 mtx_lock(&dev_pager_mtx); 141 142 /* 143 * Look up pager, creating as necessary. 144 */ 145 object1 = NULL; 146 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 147 if (object == NULL) { 148 /* 149 * Allocate object and associate it with the pager. Initialize 150 * the object's pg_color based upon the physical address of the 151 * device's memory. 152 */ 153 mtx_unlock(&dev_pager_mtx); 154 object1 = vm_object_allocate(OBJT_DEVICE, pindex); 155 object1->flags |= OBJ_COLORED; 156 object1->pg_color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE); 157 mtx_lock(&dev_pager_mtx); 158 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 159 if (object != NULL) { 160 /* 161 * We raced with other thread while allocating object. 162 */ 163 if (pindex > object->size) 164 object->size = pindex; 165 } else { 166 object = object1; 167 object1 = NULL; 168 object->handle = handle; 169 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 170 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, 171 pager_object_list); 172 } 173 } else { 174 if (pindex > object->size) 175 object->size = pindex; 176 } 177 mtx_unlock(&dev_pager_mtx); 178 dev_relthread(dev); 179 vm_object_deallocate(object1); 180 return (object); 181} 182 183static void 184dev_pager_dealloc(object) 185 vm_object_t object; 186{ 187 vm_page_t m; 188 189 VM_OBJECT_UNLOCK(object); 190 mtx_lock(&dev_pager_mtx); 191 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 192 mtx_unlock(&dev_pager_mtx); 193 VM_OBJECT_LOCK(object); 194 /* 195 * Free up our fake pages. 196 */ 197 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 198 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 199 dev_pager_putfake(m); 200 } 201} 202 203static int 204dev_pager_getpages(object, m, count, reqpage) 205 vm_object_t object; 206 vm_page_t *m; 207 int count; 208 int reqpage; 209{ 210 vm_pindex_t offset; 211 vm_paddr_t paddr; 212 vm_page_t page; 213 struct cdev *dev; 214 int i, ret; 215 int prot; 216 struct cdevsw *csw; 217 struct thread *td; 218 struct file *fpop; 219 220 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 221 dev = object->handle; 222 offset = m[reqpage]->pindex; 223 VM_OBJECT_UNLOCK(object); 224 csw = dev_refthread(dev); 225 if (csw == NULL) 226 panic("dev_pager_getpage: no cdevsw"); 227 prot = PROT_READ; /* XXX should pass in? */ 228 229 td = curthread; 230 fpop = td->td_fpop; 231 td->td_fpop = NULL; 232 ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot); 233 KASSERT(ret == 0, ("dev_pager_getpage: map function returns error")); 234 td->td_fpop = fpop; 235 dev_relthread(dev); 236 237 if ((m[reqpage]->flags & PG_FICTITIOUS) != 0) { 238 /* 239 * If the passed in reqpage page is a fake page, update it with 240 * the new physical address. 241 */ 242 VM_OBJECT_LOCK(object); 243 dev_pager_updatefake(m[reqpage], paddr); 244 if (count > 1) { 245 vm_page_lock_queues(); 246 for (i = 0; i < count; i++) { 247 if (i != reqpage) 248 vm_page_free(m[i]); 249 } 250 vm_page_unlock_queues(); 251 } 252 } else { 253 /* 254 * Replace the passed in reqpage page with our own fake page and 255 * free up the all of the original pages. 256 */ 257 page = dev_pager_getfake(paddr); 258 VM_OBJECT_LOCK(object); 259 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 260 vm_page_lock_queues(); 261 for (i = 0; i < count; i++) 262 vm_page_free(m[i]); 263 vm_page_unlock_queues(); 264 vm_page_insert(page, object, offset); 265 m[reqpage] = page; 266 } 267 268 return (VM_PAGER_OK); 269} 270 271static void 272dev_pager_putpages(object, m, count, sync, rtvals) 273 vm_object_t object; 274 vm_page_t *m; 275 int count; 276 boolean_t sync; 277 int *rtvals; 278{ 279 panic("dev_pager_putpage called"); 280} 281 282static boolean_t 283dev_pager_haspage(object, pindex, before, after) 284 vm_object_t object; 285 vm_pindex_t pindex; 286 int *before; 287 int *after; 288{ 289 if (before != NULL) 290 *before = 0; 291 if (after != NULL) 292 *after = 0; 293 return (TRUE); 294} 295 296/* 297 * Instantiate a fictitious page. Unlike physical memory pages, only 298 * the machine-independent fields must be initialized. 299 */ 300static vm_page_t 301dev_pager_getfake(paddr) 302 vm_paddr_t paddr; 303{ 304 vm_page_t m; 305 306 m = uma_zalloc(fakepg_zone, M_WAITOK); 307 308 m->flags = PG_FICTITIOUS; 309 m->oflags = VPO_BUSY; 310 m->valid = VM_PAGE_BITS_ALL; 311 m->dirty = 0; 312 m->busy = 0; 313 m->queue = PQ_NONE; 314 m->object = NULL; 315 316 m->wire_count = 1; 317 m->hold_count = 0; 318 m->phys_addr = paddr; 319 320 return (m); 321} 322 323static void 324dev_pager_putfake(m) 325 vm_page_t m; 326{ 327 if (!(m->flags & PG_FICTITIOUS)) 328 panic("dev_pager_putfake: bad page"); 329 uma_zfree(fakepg_zone, m); 330} 331 332static void 333dev_pager_updatefake(m, paddr) 334 vm_page_t m; 335 vm_paddr_t paddr; 336{ 337 if (!(m->flags & PG_FICTITIOUS)) 338 panic("dev_pager_updatefake: bad page"); 339 m->phys_addr = paddr; 340 m->valid = VM_PAGE_BITS_ALL; 341} 342