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 8.1 (Berkeley) 6/11/93 39 * $Id: device_pager.c,v 1.4 1994/10/02 17:48:58 phk Exp $ 40 */ 41 42 /* 43 * Page to/from special files. 44 */ 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/conf.h> 49 #include <sys/mman.h> 50 #include <sys/malloc.h> 51 #include <sys/proc.h> 52 53 #include <vm/vm.h> 54 #include <vm/vm_kern.h> 55 #include <vm/vm_page.h> 56 #include <vm/device_pager.h> 57 58 struct pagerlst dev_pager_list; /* list of managed devices */ 59 struct pglist dev_pager_fakelist; /* list of available vm_page_t's */ 60 61 #ifdef DEBUG 62 int dpagerdebug = 0; 63 64 #define DDB_FOLLOW 0x01 65 #define DDB_INIT 0x02 66 #define DDB_ALLOC 0x04 67 #define DDB_FAIL 0x08 68 #endif 69 70 static vm_pager_t dev_pager_alloc __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t)); 71 static void dev_pager_dealloc __P((vm_pager_t)); 72 static int dev_pager_getpage __P((vm_pager_t, vm_page_t, boolean_t)); 73 static boolean_t dev_pager_haspage __P((vm_pager_t, vm_offset_t)); 74 static void dev_pager_init __P((void)); 75 static int dev_pager_putpage __P((vm_pager_t, vm_page_t, boolean_t)); 76 static vm_page_t dev_pager_getfake __P((vm_offset_t)); 77 static void dev_pager_putfake __P((vm_page_t)); 78 79 struct pagerops devicepagerops = { 80 dev_pager_init, 81 dev_pager_alloc, 82 dev_pager_dealloc, 83 dev_pager_getpage, 84 0, 85 dev_pager_putpage, 86 0, 87 dev_pager_haspage 88 }; 89 90 static void 91 dev_pager_init() 92 { 93 #ifdef DEBUG 94 if (dpagerdebug & DDB_FOLLOW) 95 printf("dev_pager_init()\n"); 96 #endif 97 TAILQ_INIT(&dev_pager_list); 98 TAILQ_INIT(&dev_pager_fakelist); 99 } 100 101 static vm_pager_t 102 dev_pager_alloc(handle, size, prot, foff) 103 caddr_t handle; 104 vm_size_t size; 105 vm_prot_t prot; 106 vm_offset_t foff; 107 { 108 dev_t dev; 109 vm_pager_t pager; 110 int (*mapfunc) (); 111 vm_object_t object; 112 dev_pager_t devp; 113 unsigned int npages, off; 114 115 #ifdef DEBUG 116 if (dpagerdebug & DDB_FOLLOW) 117 printf("dev_pager_alloc(%x, %x, %x, %x)\n", 118 handle, size, prot, foff); 119 #endif 120 #ifdef DIAGNOSTIC 121 /* 122 * Pageout to device, should never happen. 123 */ 124 if (handle == NULL) 125 panic("dev_pager_alloc called"); 126 #endif 127 128 /* 129 * Make sure this device can be mapped. 130 */ 131 dev = (dev_t) (u_long) handle; 132 mapfunc = cdevsw[major(dev)].d_mmap; 133 if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop) 134 return (NULL); 135 136 /* 137 * Offset should be page aligned. 138 */ 139 if (foff & (PAGE_SIZE - 1)) 140 return (NULL); 141 142 /* 143 * Check that the specified range of the device allows the desired 144 * protection. 145 * 146 * XXX assumes VM_PROT_* == PROT_* 147 */ 148 npages = atop(round_page(size)); 149 for (off = foff; npages--; off += PAGE_SIZE) 150 if ((*mapfunc) (dev, off, (int) prot) == -1) 151 return (NULL); 152 153 /* 154 * Look up pager, creating as necessary. 155 */ 156 top: 157 pager = vm_pager_lookup(&dev_pager_list, handle); 158 if (pager == NULL) { 159 /* 160 * Allocate and initialize pager structs 161 */ 162 pager = (vm_pager_t) malloc(sizeof *pager, M_VMPAGER, M_WAITOK); 163 if (pager == NULL) 164 return (NULL); 165 devp = (dev_pager_t) malloc(sizeof *devp, M_VMPGDATA, M_WAITOK); 166 if (devp == NULL) { 167 free((caddr_t) pager, M_VMPAGER); 168 return (NULL); 169 } 170 pager->pg_handle = handle; 171 pager->pg_ops = &devicepagerops; 172 pager->pg_type = PG_DEVICE; 173 pager->pg_data = (caddr_t) 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) foff, 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, we 185 * 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 removes the 203 * 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 } 214 215 static void 216 dev_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. Note: cannot use vm_object_lookup since object has 230 * already been removed from the hash chain. 231 */ 232 devp = (dev_pager_t) pager->pg_data; 233 object = devp->devp_object; 234 #ifdef DEBUG 235 if (dpagerdebug & DDB_ALLOC) 236 printf("dev_pager_dealloc: devp %x object %x\n", devp, object); 237 #endif 238 /* 239 * Free up our fake pages. 240 */ 241 while ((m = devp->devp_pglist.tqh_first) != 0) { 242 TAILQ_REMOVE(&devp->devp_pglist, m, pageq); 243 dev_pager_putfake(m); 244 } 245 free((caddr_t) devp, M_VMPGDATA); 246 free((caddr_t) pager, M_VMPAGER); 247 } 248 249 static int 250 dev_pager_getpage(pager, m, sync) 251 vm_pager_t pager; 252 vm_page_t m; 253 boolean_t sync; 254 { 255 register vm_object_t object; 256 vm_offset_t offset, paddr; 257 vm_page_t page; 258 dev_t dev; 259 int s; 260 int (*mapfunc) (), prot; 261 262 #ifdef DEBUG 263 if (dpagerdebug & DDB_FOLLOW) 264 printf("dev_pager_getpage(%x, %x)\n", pager, m); 265 #endif 266 267 object = m->object; 268 dev = (dev_t) (u_long) pager->pg_handle; 269 offset = m->offset + object->paging_offset; 270 prot = PROT_READ; /* XXX should pass in? */ 271 mapfunc = cdevsw[major(dev)].d_mmap; 272 273 if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop) 274 panic("dev_pager_getpage: no map function"); 275 276 paddr = pmap_phys_address((*mapfunc) ((dev_t) dev, (int) offset, prot)); 277 #ifdef DIAGNOSTIC 278 if (paddr == -1) 279 panic("dev_pager_getpage: map function returns error"); 280 #endif 281 /* 282 * Replace the passed in page with our own fake page and free up the 283 * original. 284 */ 285 page = dev_pager_getfake(paddr); 286 TAILQ_INSERT_TAIL(&((dev_pager_t) pager->pg_data)->devp_pglist, 287 page, pageq); 288 vm_object_lock(object); 289 vm_page_lock_queues(); 290 PAGE_WAKEUP(m); 291 vm_page_free(m); 292 vm_page_unlock_queues(); 293 s = splhigh(); 294 vm_page_insert(page, object, offset); 295 splx(s); 296 if (offset + PAGE_SIZE > object->size) 297 object->size = offset + PAGE_SIZE; /* XXX anal */ 298 vm_object_unlock(object); 299 300 return (VM_PAGER_OK); 301 } 302 303 static int 304 dev_pager_putpage(pager, m, sync) 305 vm_pager_t pager; 306 vm_page_t m; 307 boolean_t sync; 308 { 309 #ifdef DEBUG 310 if (dpagerdebug & DDB_FOLLOW) 311 printf("dev_pager_putpage(%x, %x)\n", pager, m); 312 #endif 313 if (pager == NULL) 314 return 0; 315 panic("dev_pager_putpage called"); 316 } 317 318 static boolean_t 319 dev_pager_haspage(pager, offset) 320 vm_pager_t pager; 321 vm_offset_t offset; 322 { 323 #ifdef DEBUG 324 if (dpagerdebug & DDB_FOLLOW) 325 printf("dev_pager_haspage(%x, %x)\n", pager, offset); 326 #endif 327 return (TRUE); 328 } 329 330 static vm_page_t 331 dev_pager_getfake(paddr) 332 vm_offset_t paddr; 333 { 334 vm_page_t m; 335 int i; 336 337 if (dev_pager_fakelist.tqh_first == NULL) { 338 m = (vm_page_t) malloc(PAGE_SIZE * 2, M_VMPGDATA, M_WAITOK); 339 for (i = (PAGE_SIZE * 2) / sizeof(*m); i > 0; i--) { 340 TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq); 341 m++; 342 } 343 } 344 m = dev_pager_fakelist.tqh_first; 345 TAILQ_REMOVE(&dev_pager_fakelist, m, pageq); 346 347 m->flags = PG_BUSY | PG_FICTITIOUS; 348 m->dirty = 0; 349 m->valid = VM_PAGE_BITS_ALL; 350 m->busy = 0; 351 m->bmapped = 0; 352 353 m->wire_count = 1; 354 m->phys_addr = paddr; 355 356 return (m); 357 } 358 359 static void 360 dev_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