1 /* $OpenBSD: uvm_device.c,v 1.28 2007/10/29 17:08:08 chl Exp $ */ 2 /* $NetBSD: uvm_device.c,v 1.30 2000/11/25 06:27:59 chs Exp $ */ 3 4 /* 5 * 6 * Copyright (c) 1997 Charles D. Cranor and Washington University. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by Charles D. Cranor and 20 * Washington University. 21 * 4. The name of the author may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 * 35 * from: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp 36 */ 37 38 /* 39 * uvm_device.c: the device pager. 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/conf.h> 45 #include <sys/proc.h> 46 #include <sys/malloc.h> 47 #include <sys/vnode.h> 48 49 #include <uvm/uvm.h> 50 #include <uvm/uvm_device.h> 51 52 /* 53 * private global data structure 54 * 55 * we keep a list of active device objects in the system. 56 */ 57 58 LIST_HEAD(udv_list_struct, uvm_device); 59 static struct udv_list_struct udv_list; 60 static simple_lock_data_t udv_lock; 61 62 /* 63 * functions 64 */ 65 66 static void udv_init(void); 67 static void udv_reference(struct uvm_object *); 68 static void udv_detach(struct uvm_object *); 69 static int udv_fault(struct uvm_faultinfo *, vaddr_t, 70 vm_page_t *, int, int, vm_fault_t, 71 vm_prot_t, int); 72 static boolean_t udv_flush(struct uvm_object *, voff_t, voff_t, 73 int); 74 75 /* 76 * master pager structure 77 */ 78 79 struct uvm_pagerops uvm_deviceops = { 80 udv_init, 81 udv_reference, 82 udv_detach, 83 udv_fault, 84 udv_flush, 85 }; 86 87 /* 88 * the ops! 89 */ 90 91 /* 92 * udv_init 93 * 94 * init pager private data structures. 95 */ 96 97 void 98 udv_init() 99 { 100 101 LIST_INIT(&udv_list); 102 simple_lock_init(&udv_lock); 103 } 104 105 /* 106 * udv_attach 107 * 108 * get a VM object that is associated with a device. allocate a new 109 * one if needed. 110 * 111 * => caller must _not_ already be holding the lock on the uvm_object. 112 * => in fact, nothing should be locked so that we can sleep here. 113 */ 114 struct uvm_object * 115 udv_attach(arg, accessprot, off, size) 116 void *arg; 117 vm_prot_t accessprot; 118 voff_t off; /* used only for access check */ 119 vsize_t size; /* used only for access check */ 120 { 121 dev_t device = *((dev_t *)arg); 122 struct uvm_device *udv, *lcv; 123 paddr_t (*mapfn)(dev_t, off_t, int); 124 UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); 125 126 UVMHIST_LOG(maphist, "(device=0x%lx)", device,0,0,0); 127 128 /* 129 * before we do anything, ensure this device supports mmap 130 */ 131 132 mapfn = cdevsw[major(device)].d_mmap; 133 if (mapfn == NULL || 134 mapfn == (paddr_t (*)(dev_t, off_t, int)) enodev || 135 mapfn == (paddr_t (*)(dev_t, off_t, int)) nullop) 136 return(NULL); 137 138 /* 139 * Negative offsets on the object are not allowed. 140 */ 141 142 if (off < 0) 143 return(NULL); 144 145 /* 146 * Check that the specified range of the device allows the 147 * desired protection. 148 * 149 * XXX assumes VM_PROT_* == PROT_* 150 * XXX clobbers off and size, but nothing else here needs them. 151 */ 152 153 while (size != 0) { 154 if ((*mapfn)(device, off, accessprot) == -1) 155 return (NULL); 156 off += PAGE_SIZE; size -= PAGE_SIZE; 157 } 158 159 /* 160 * keep looping until we get it 161 */ 162 163 for (;;) { 164 165 /* 166 * first, attempt to find it on the main list 167 */ 168 169 simple_lock(&udv_lock); 170 LIST_FOREACH(lcv, &udv_list, u_list) { 171 if (device == lcv->u_device) 172 break; 173 } 174 175 /* 176 * got it on main list. put a hold on it and unlock udv_lock. 177 */ 178 179 if (lcv) { 180 181 /* 182 * if someone else has a hold on it, sleep and start 183 * over again. 184 */ 185 186 if (lcv->u_flags & UVM_DEVICE_HOLD) { 187 lcv->u_flags |= UVM_DEVICE_WANTED; 188 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 189 "udv_attach",0); 190 continue; 191 } 192 193 /* we are now holding it */ 194 lcv->u_flags |= UVM_DEVICE_HOLD; 195 simple_unlock(&udv_lock); 196 197 /* 198 * bump reference count, unhold, return. 199 */ 200 201 simple_lock(&lcv->u_obj.vmobjlock); 202 lcv->u_obj.uo_refs++; 203 simple_unlock(&lcv->u_obj.vmobjlock); 204 205 simple_lock(&udv_lock); 206 if (lcv->u_flags & UVM_DEVICE_WANTED) 207 wakeup(lcv); 208 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 209 simple_unlock(&udv_lock); 210 return(&lcv->u_obj); 211 } 212 213 /* 214 * did not find it on main list. need to malloc a new one. 215 */ 216 217 simple_unlock(&udv_lock); 218 /* NOTE: we could sleep in the following malloc() */ 219 udv = malloc(sizeof(*udv), M_TEMP, M_WAITOK); 220 simple_lock(&udv_lock); 221 222 /* 223 * now we have to double check to make sure no one added it 224 * to the list while we were sleeping... 225 */ 226 227 LIST_FOREACH(lcv, &udv_list, u_list) { 228 if (device == lcv->u_device) 229 break; 230 } 231 232 /* 233 * did we lose a race to someone else? 234 * free our memory and retry. 235 */ 236 237 if (lcv) { 238 simple_unlock(&udv_lock); 239 free(udv, M_TEMP); 240 continue; 241 } 242 243 /* 244 * we have it! init the data structures, add to list 245 * and return. 246 */ 247 248 simple_lock_init(&udv->u_obj.vmobjlock); 249 udv->u_obj.pgops = &uvm_deviceops; 250 TAILQ_INIT(&udv->u_obj.memq); 251 udv->u_obj.uo_npages = 0; 252 udv->u_obj.uo_refs = 1; 253 udv->u_flags = 0; 254 udv->u_device = device; 255 LIST_INSERT_HEAD(&udv_list, udv, u_list); 256 simple_unlock(&udv_lock); 257 return(&udv->u_obj); 258 } 259 /*NOTREACHED*/ 260 } 261 262 /* 263 * udv_reference 264 * 265 * add a reference to a VM object. Note that the reference count must 266 * already be one (the passed in reference) so there is no chance of the 267 * udv being released or locked out here. 268 * 269 * => caller must call with object unlocked. 270 */ 271 272 static void 273 udv_reference(uobj) 274 struct uvm_object *uobj; 275 { 276 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 277 278 simple_lock(&uobj->vmobjlock); 279 uobj->uo_refs++; 280 UVMHIST_LOG(maphist, "<- done (uobj=%p, ref = %ld)", 281 uobj, uobj->uo_refs,0,0); 282 simple_unlock(&uobj->vmobjlock); 283 } 284 285 /* 286 * udv_detach 287 * 288 * remove a reference to a VM object. 289 * 290 * => caller must call with object unlocked and map locked. 291 */ 292 293 static void 294 udv_detach(uobj) 295 struct uvm_object *uobj; 296 { 297 struct uvm_device *udv = (struct uvm_device *)uobj; 298 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 299 300 /* 301 * loop until done 302 */ 303 again: 304 simple_lock(&uobj->vmobjlock); 305 if (uobj->uo_refs > 1) { 306 uobj->uo_refs--; 307 simple_unlock(&uobj->vmobjlock); 308 UVMHIST_LOG(maphist," <- done, uobj=%p, ref=%ld", 309 uobj,uobj->uo_refs,0,0); 310 return; 311 } 312 KASSERT(uobj->uo_npages == 0 && TAILQ_EMPTY(&uobj->memq)); 313 314 /* 315 * is it being held? if so, wait until others are done. 316 */ 317 318 simple_lock(&udv_lock); 319 if (udv->u_flags & UVM_DEVICE_HOLD) { 320 udv->u_flags |= UVM_DEVICE_WANTED; 321 simple_unlock(&uobj->vmobjlock); 322 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 323 goto again; 324 } 325 326 /* 327 * got it! nuke it now. 328 */ 329 330 LIST_REMOVE(udv, u_list); 331 if (udv->u_flags & UVM_DEVICE_WANTED) 332 wakeup(udv); 333 simple_unlock(&udv_lock); 334 simple_unlock(&uobj->vmobjlock); 335 free(udv, M_TEMP); 336 UVMHIST_LOG(maphist," <- done, freed uobj=%p", uobj,0,0,0); 337 } 338 339 340 /* 341 * udv_flush 342 * 343 * flush pages out of a uvm object. a no-op for devices. 344 */ 345 346 static boolean_t 347 udv_flush(uobj, start, stop, flags) 348 struct uvm_object *uobj; 349 voff_t start, stop; 350 int flags; 351 { 352 353 return(TRUE); 354 } 355 356 /* 357 * udv_fault: non-standard fault routine for device "pages" 358 * 359 * => rather than having a "get" function, we have a fault routine 360 * since we don't return vm_pages we need full control over the 361 * pmap_enter map in 362 * => all the usual fault data structured are locked by the caller 363 * (i.e. maps(read), amap (if any), uobj) 364 * => on return, we unlock all fault data structures 365 * => flags: PGO_ALLPAGES: get all of the pages 366 * PGO_LOCKED: fault data structures are locked 367 * XXX: currently PGO_LOCKED is always required ... consider removing 368 * it as a flag 369 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 370 */ 371 372 static int 373 udv_fault(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags) 374 struct uvm_faultinfo *ufi; 375 vaddr_t vaddr; 376 vm_page_t *pps; 377 int npages, centeridx, flags; 378 vm_fault_t fault_type; 379 vm_prot_t access_type; 380 { 381 struct vm_map_entry *entry = ufi->entry; 382 struct uvm_object *uobj = entry->object.uvm_obj; 383 struct uvm_device *udv = (struct uvm_device *)uobj; 384 vaddr_t curr_va; 385 off_t curr_offset; 386 paddr_t paddr, mdpgno; 387 int lcv, retval; 388 dev_t device; 389 paddr_t (*mapfn)(dev_t, off_t, int); 390 vm_prot_t mapprot; 391 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 392 UVMHIST_LOG(maphist," flags=%ld", flags,0,0,0); 393 394 /* 395 * we do not allow device mappings to be mapped copy-on-write 396 * so we kill any attempt to do so here. 397 */ 398 399 if (UVM_ET_ISCOPYONWRITE(entry)) { 400 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%lx)", 401 entry->etype, 0,0,0); 402 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 403 return(VM_PAGER_ERROR); 404 } 405 406 /* 407 * get device map function. 408 */ 409 410 device = udv->u_device; 411 mapfn = cdevsw[major(device)].d_mmap; 412 413 /* 414 * now we must determine the offset in udv to use and the VA to 415 * use for pmap_enter. note that we always use orig_map's pmap 416 * for pmap_enter (even if we have a submap). since virtual 417 * addresses in a submap must match the main map, this is ok. 418 */ 419 420 /* udv offset = (offset from start of entry) + entry's offset */ 421 curr_offset = entry->offset + (vaddr - entry->start); 422 /* pmap va = vaddr (virtual address of pps[0]) */ 423 curr_va = vaddr; 424 425 /* 426 * loop over the page range entering in as needed 427 */ 428 429 retval = VM_PAGER_OK; 430 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 431 curr_va += PAGE_SIZE) { 432 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 433 continue; 434 435 if (pps[lcv] == PGO_DONTCARE) 436 continue; 437 438 mdpgno = (*mapfn)(device, curr_offset, access_type); 439 if (mdpgno == -1) { 440 retval = VM_PAGER_ERROR; 441 break; 442 } 443 paddr = pmap_phys_address(mdpgno); 444 mapprot = ufi->entry->protection; 445 UVMHIST_LOG(maphist, 446 " MAPPING: device: pm=%p, va=0x%lx, pa=0x%lx, at=%ld", 447 ufi->orig_map->pmap, curr_va, (u_long)paddr, mapprot); 448 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 449 mapprot, PMAP_CANFAIL | mapprot) != 0) { 450 /* 451 * pmap_enter() didn't have the resource to 452 * enter this mapping. Unlock everything, 453 * wait for the pagedaemon to free up some 454 * pages, and then tell uvm_fault() to start 455 * the fault again. 456 * 457 * XXX Needs some rethinking for the PGO_ALLPAGES 458 * XXX case. 459 */ 460 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 461 uobj, NULL); 462 463 /* sync what we have so far */ 464 pmap_update(ufi->orig_map->pmap); 465 uvm_wait("udv_fault"); 466 return (VM_PAGER_REFAULT); 467 } 468 } 469 470 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 471 pmap_update(ufi->orig_map->pmap); 472 return (retval); 473 } 474