device_pager.c revision 1541
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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)device_pager.c 8.5 (Berkeley) 1/12/94 39 */ 40 41/* 42 * Page to/from special files. 43 */ 44 45#include <sys/param.h> 46#include <sys/systm.h> 47#include <sys/conf.h> 48#include <sys/mman.h> 49#include <sys/malloc.h> 50 51#include <vm/vm.h> 52#include <vm/vm_kern.h> 53#include <vm/vm_page.h> 54#include <vm/device_pager.h> 55 56struct pagerlst dev_pager_list; /* list of managed devices */ 57struct pglist dev_pager_fakelist; /* list of available vm_page_t's */ 58 59#ifdef DEBUG 60int dpagerdebug = 0; 61#define DDB_FOLLOW 0x01 62#define DDB_INIT 0x02 63#define DDB_ALLOC 0x04 64#define DDB_FAIL 0x08 65#endif 66 67static vm_pager_t dev_pager_alloc 68 __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t)); 69static void dev_pager_dealloc __P((vm_pager_t)); 70static int dev_pager_getpage 71 __P((vm_pager_t, vm_page_t *, int, boolean_t)); 72static boolean_t dev_pager_haspage __P((vm_pager_t, vm_offset_t)); 73static void dev_pager_init __P((void)); 74static int dev_pager_putpage 75 __P((vm_pager_t, vm_page_t *, int, boolean_t)); 76static vm_page_t dev_pager_getfake __P((vm_offset_t)); 77static void dev_pager_putfake __P((vm_page_t)); 78 79struct pagerops devicepagerops = { 80 dev_pager_init, 81 dev_pager_alloc, 82 dev_pager_dealloc, 83 dev_pager_getpage, 84 dev_pager_putpage, 85 dev_pager_haspage, 86 vm_pager_clusternull 87}; 88 89static void 90dev_pager_init() 91{ 92#ifdef DEBUG 93 if (dpagerdebug & DDB_FOLLOW) 94 printf("dev_pager_init()\n"); 95#endif 96 TAILQ_INIT(&dev_pager_list); 97 TAILQ_INIT(&dev_pager_fakelist); 98} 99 100static vm_pager_t 101dev_pager_alloc(handle, size, prot, foff) 102 caddr_t handle; 103 vm_size_t size; 104 vm_prot_t prot; 105 vm_offset_t foff; 106{ 107 dev_t dev; 108 vm_pager_t pager; 109 int (*mapfunc)(); 110 vm_object_t object; 111 dev_pager_t devp; 112 int npages, off; 113 114#ifdef DEBUG 115 if (dpagerdebug & DDB_FOLLOW) 116 printf("dev_pager_alloc(%x, %x, %x, %x)\n", 117 handle, size, prot, foff); 118#endif 119#ifdef DIAGNOSTIC 120 /* 121 * Pageout to device, should never happen. 122 */ 123 if (handle == NULL) 124 panic("dev_pager_alloc called"); 125#endif 126 127 /* 128 * Make sure this device can be mapped. 129 */ 130 dev = (dev_t)handle; 131 mapfunc = cdevsw[major(dev)].d_mmap; 132 if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop) 133 return(NULL); 134 135 /* 136 * Offset should be page aligned. 137 */ 138 if (foff & PAGE_MASK) 139 return(NULL); 140 141 /* 142 * Check that the specified range of the device allows the 143 * desired protection. 144 * 145 * XXX assumes VM_PROT_* == PROT_* 146 */ 147 npages = atop(round_page(size)); 148 for (off = foff; npages--; off += PAGE_SIZE) 149 if ((*mapfunc)(dev, off, (int)prot) == -1) 150 return(NULL); 151 152 /* 153 * Look up pager, creating as necessary. 154 */ 155top: 156 pager = vm_pager_lookup(&dev_pager_list, handle); 157 if (pager == NULL) { 158 /* 159 * Allocate and initialize pager structs 160 */ 161 pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK); 162 if (pager == NULL) 163 return(NULL); 164 devp = (dev_pager_t)malloc(sizeof *devp, M_VMPGDATA, M_WAITOK); 165 if (devp == NULL) { 166 free((caddr_t)pager, M_VMPAGER); 167 return(NULL); 168 } 169 pager->pg_handle = handle; 170 pager->pg_ops = &devicepagerops; 171 pager->pg_type = PG_DEVICE; 172 pager->pg_flags = 0; 173 pager->pg_data = devp; 174 TAILQ_INIT(&devp->devp_pglist); 175 /* 176 * Allocate object and associate it with the pager. 177 */ 178 object = devp->devp_object = vm_object_allocate(0); 179 vm_object_enter(object, pager); 180 vm_object_setpager(object, pager, (vm_offset_t)0, FALSE); 181 /* 182 * Finally, put it on the managed list so other can find it. 183 * First we re-lookup in case someone else beat us to this 184 * point (due to blocking in the various mallocs). If so, 185 * we free everything and start over. 186 */ 187 if (vm_pager_lookup(&dev_pager_list, handle)) { 188 free((caddr_t)devp, M_VMPGDATA); 189 free((caddr_t)pager, M_VMPAGER); 190 goto top; 191 } 192 TAILQ_INSERT_TAIL(&dev_pager_list, pager, pg_list); 193#ifdef DEBUG 194 if (dpagerdebug & DDB_ALLOC) { 195 printf("dev_pager_alloc: pager %x devp %x object %x\n", 196 pager, devp, object); 197 vm_object_print(object, FALSE); 198 } 199#endif 200 } else { 201 /* 202 * vm_object_lookup() gains a reference and also 203 * removes the object from the cache. 204 */ 205 object = vm_object_lookup(pager); 206#ifdef DIAGNOSTIC 207 devp = (dev_pager_t)pager->pg_data; 208 if (object != devp->devp_object) 209 panic("dev_pager_setup: bad object"); 210#endif 211 } 212 return(pager); 213} 214 215static void 216dev_pager_dealloc(pager) 217 vm_pager_t pager; 218{ 219 dev_pager_t devp; 220 vm_object_t object; 221 vm_page_t m; 222 223#ifdef DEBUG 224 if (dpagerdebug & DDB_FOLLOW) 225 printf("dev_pager_dealloc(%x)\n", pager); 226#endif 227 TAILQ_REMOVE(&dev_pager_list, pager, pg_list); 228 /* 229 * Get the object. 230 * Note: cannot use vm_object_lookup since object has already 231 * been removed from the hash chain. 232 */ 233 devp = (dev_pager_t)pager->pg_data; 234 object = devp->devp_object; 235#ifdef DEBUG 236 if (dpagerdebug & DDB_ALLOC) 237 printf("dev_pager_dealloc: devp %x object %x\n", devp, object); 238#endif 239 /* 240 * Free up our fake pages. 241 */ 242 while ((m = devp->devp_pglist.tqh_first) != NULL) { 243 TAILQ_REMOVE(&devp->devp_pglist, m, pageq); 244 dev_pager_putfake(m); 245 } 246 free((caddr_t)devp, M_VMPGDATA); 247 free((caddr_t)pager, M_VMPAGER); 248} 249 250static int 251dev_pager_getpage(pager, mlist, npages, sync) 252 vm_pager_t pager; 253 vm_page_t *mlist; 254 int npages; 255 boolean_t sync; 256{ 257 register vm_object_t object; 258 vm_offset_t offset, paddr; 259 vm_page_t page; 260 dev_t dev; 261 int (*mapfunc)(), prot; 262 vm_page_t m; 263 264#ifdef DEBUG 265 if (dpagerdebug & DDB_FOLLOW) 266 printf("dev_pager_getpage(%x, %x, %x, %x)\n", 267 pager, mlist, npages, sync); 268#endif 269 270 if (npages != 1) 271 panic("dev_pager_getpage: cannot handle multiple pages"); 272 m = *mlist; 273 274 object = m->object; 275 dev = (dev_t)pager->pg_handle; 276 offset = m->offset + object->paging_offset; 277 prot = PROT_READ; /* XXX should pass in? */ 278 mapfunc = cdevsw[major(dev)].d_mmap; 279#ifdef DIAGNOSTIC 280 if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop) 281 panic("dev_pager_getpage: no map function"); 282#endif 283 paddr = pmap_phys_address((*mapfunc)(dev, (int)offset, prot)); 284#ifdef DIAGNOSTIC 285 if (paddr == -1) 286 panic("dev_pager_getpage: map function returns error"); 287#endif 288 /* 289 * Replace the passed in page with our own fake page and free 290 * up the original. 291 */ 292 page = dev_pager_getfake(paddr); 293 TAILQ_INSERT_TAIL(&((dev_pager_t)pager->pg_data)->devp_pglist, page, 294 pageq); 295 vm_object_lock(object); 296 vm_page_lock_queues(); 297 vm_page_free(m); 298 vm_page_insert(page, object, offset); 299 vm_page_unlock_queues(); 300 PAGE_WAKEUP(m); 301 if (offset + PAGE_SIZE > object->size) 302 object->size = offset + PAGE_SIZE; /* XXX anal */ 303 vm_object_unlock(object); 304 305 return(VM_PAGER_OK); 306} 307 308static int 309dev_pager_putpage(pager, mlist, npages, sync) 310 vm_pager_t pager; 311 vm_page_t *mlist; 312 int npages; 313 boolean_t sync; 314{ 315#ifdef DEBUG 316 if (dpagerdebug & DDB_FOLLOW) 317 printf("dev_pager_putpage(%x, %x, %x, %x)\n", 318 pager, mlist, npages, sync); 319#endif 320 if (pager == NULL) 321 return; 322 panic("dev_pager_putpage called"); 323} 324 325static boolean_t 326dev_pager_haspage(pager, offset) 327 vm_pager_t pager; 328 vm_offset_t offset; 329{ 330#ifdef DEBUG 331 if (dpagerdebug & DDB_FOLLOW) 332 printf("dev_pager_haspage(%x, %x)\n", pager, offset); 333#endif 334 return(TRUE); 335} 336 337static vm_page_t 338dev_pager_getfake(paddr) 339 vm_offset_t paddr; 340{ 341 vm_page_t m; 342 int i; 343 344 if (dev_pager_fakelist.tqh_first == NULL) { 345 m = (vm_page_t)malloc(PAGE_SIZE, M_VMPGDATA, M_WAITOK); 346 for (i = PAGE_SIZE / sizeof(*m); i > 0; i--) { 347 TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq); 348 m++; 349 } 350 } 351 m = dev_pager_fakelist.tqh_first; 352 TAILQ_REMOVE(&dev_pager_fakelist, m, pageq); 353 m->flags = PG_BUSY | PG_CLEAN | PG_FAKE | PG_FICTITIOUS; 354 m->phys_addr = paddr; 355 m->wire_count = 1; 356 return(m); 357} 358 359static void 360dev_pager_putfake(m) 361 vm_page_t m; 362{ 363#ifdef DIAGNOSTIC 364 if (!(m->flags & PG_FICTITIOUS)) 365 panic("dev_pager_putfake: bad page"); 366#endif 367 TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq); 368} 369