1 /* $NetBSD: uvm_device.c,v 1.22 2000/05/28 10:21:55 drochner Exp $ */ 2 3 /* 4 * 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Charles D. Cranor and 19 * Washington University. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 * from: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp 35 */ 36 37 #include "opt_uvmhist.h" 38 39 /* 40 * uvm_device.c: the device pager. 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/conf.h> 46 #include <sys/proc.h> 47 #include <sys/malloc.h> 48 #include <sys/vnode.h> 49 50 #include <vm/vm.h> 51 #include <vm/vm_page.h> 52 #include <vm/vm_kern.h> 53 54 #include <uvm/uvm.h> 55 #include <uvm/uvm_device.h> 56 57 /* 58 * private global data structure 59 * 60 * we keep a list of active device objects in the system. 61 */ 62 63 LIST_HEAD(udv_list_struct, uvm_device); 64 static struct udv_list_struct udv_list; 65 static simple_lock_data_t udv_lock; 66 67 /* 68 * functions 69 */ 70 71 static void udv_init __P((void)); 72 static void udv_reference __P((struct uvm_object *)); 73 static void udv_detach __P((struct uvm_object *)); 74 static int udv_fault __P((struct uvm_faultinfo *, vaddr_t, 75 vm_page_t *, int, int, vm_fault_t, 76 vm_prot_t, int)); 77 static int udv_asyncget __P((struct uvm_object *, voff_t, 78 int)); 79 static boolean_t udv_flush __P((struct uvm_object *, voff_t, voff_t, 80 int)); 81 static int udv_put __P((struct uvm_object *, vm_page_t *, 82 int, boolean_t)); 83 84 /* 85 * master pager structure 86 */ 87 88 struct uvm_pagerops uvm_deviceops = { 89 udv_init, 90 udv_reference, 91 udv_detach, 92 udv_fault, 93 udv_flush, 94 NULL, /* no get function since we have udv_fault */ 95 udv_asyncget, 96 udv_put, 97 NULL, /* no cluster function */ 98 NULL, /* no put cluster function */ 99 NULL, /* no AIO-DONE function since no async i/o */ 100 NULL, /* no releasepg function since no normal pages */ 101 }; 102 103 /* 104 * the ops! 105 */ 106 107 /* 108 * udv_init 109 * 110 * init pager private data structures. 111 */ 112 113 void 114 udv_init() 115 { 116 117 LIST_INIT(&udv_list); 118 simple_lock_init(&udv_lock); 119 } 120 121 /* 122 * udv_attach 123 * 124 * get a VM object that is associated with a device. allocate a new 125 * one if needed. 126 * 127 * => caller must _not_ already be holding the lock on the uvm_object. 128 * => in fact, nothing should be locked so that we can sleep here. 129 */ 130 struct uvm_object * 131 udv_attach(arg, accessprot, off, size) 132 void *arg; 133 vm_prot_t accessprot; 134 voff_t off; /* used only for access check */ 135 vsize_t size; /* used only for access check */ 136 { 137 dev_t device = *((dev_t *) arg); 138 struct uvm_device *udv, *lcv; 139 int (*mapfn) __P((dev_t, int, int)); 140 UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); 141 142 UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0); 143 144 /* 145 * before we do anything, ensure this device supports mmap 146 */ 147 148 mapfn = cdevsw[major(device)].d_mmap; 149 if (mapfn == NULL || 150 mapfn == (int (*) __P((dev_t, int, int))) enodev || 151 mapfn == (int (*) __P((dev_t, int, int))) nullop) 152 return(NULL); 153 154 /* 155 * As long as the device d_mmap interface gets an "int" 156 * offset, we have to watch out not to overflow its 157 * numeric range. (assuming it will be interpreted as 158 * "unsigned") 159 */ 160 if (((off + size - 1) & (u_int)-1) != off + size - 1) 161 return (0); 162 163 /* 164 * Check that the specified range of the device allows the 165 * desired protection. 166 * 167 * XXX assumes VM_PROT_* == PROT_* 168 * XXX clobbers off and size, but nothing else here needs them. 169 */ 170 171 while (size != 0) { 172 if ((*mapfn)(device, off, accessprot) == -1) 173 return (NULL); 174 off += PAGE_SIZE; size -= PAGE_SIZE; 175 } 176 177 /* 178 * keep looping until we get it 179 */ 180 181 while (1) { 182 183 /* 184 * first, attempt to find it on the main list 185 */ 186 187 simple_lock(&udv_lock); 188 for (lcv = udv_list.lh_first ; lcv != NULL ; lcv = lcv->u_list.le_next) { 189 if (device == lcv->u_device) 190 break; 191 } 192 193 /* 194 * got it on main list. put a hold on it and unlock udv_lock. 195 */ 196 197 if (lcv) { 198 199 /* 200 * if someone else has a hold on it, sleep and start 201 * over again. 202 */ 203 204 if (lcv->u_flags & UVM_DEVICE_HOLD) { 205 lcv->u_flags |= UVM_DEVICE_WANTED; 206 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 207 "udv_attach",0); 208 continue; 209 } 210 211 /* we are now holding it */ 212 lcv->u_flags |= UVM_DEVICE_HOLD; 213 simple_unlock(&udv_lock); 214 215 /* 216 * bump reference count, unhold, return. 217 */ 218 219 simple_lock(&lcv->u_obj.vmobjlock); 220 lcv->u_obj.uo_refs++; 221 simple_unlock(&lcv->u_obj.vmobjlock); 222 223 simple_lock(&udv_lock); 224 if (lcv->u_flags & UVM_DEVICE_WANTED) 225 wakeup(lcv); 226 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 227 simple_unlock(&udv_lock); 228 return(&lcv->u_obj); 229 } 230 231 /* 232 * did not find it on main list. need to malloc a new one. 233 */ 234 235 simple_unlock(&udv_lock); 236 /* NOTE: we could sleep in the following malloc() */ 237 MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, M_WAITOK); 238 simple_lock(&udv_lock); 239 240 /* 241 * now we have to double check to make sure no one added it 242 * to the list while we were sleeping... 243 */ 244 245 for (lcv = udv_list.lh_first ; lcv != NULL ; 246 lcv = lcv->u_list.le_next) { 247 if (device == lcv->u_device) 248 break; 249 } 250 251 /* 252 * did we lose a race to someone else? free our memory and retry. 253 */ 254 255 if (lcv) { 256 simple_unlock(&udv_lock); 257 FREE(udv, M_TEMP); 258 continue; 259 } 260 261 /* 262 * we have it! init the data structures, add to list 263 * and return. 264 */ 265 266 simple_lock_init(&udv->u_obj.vmobjlock); 267 udv->u_obj.pgops = &uvm_deviceops; 268 TAILQ_INIT(&udv->u_obj.memq); /* not used, but be safe */ 269 udv->u_obj.uo_npages = 0; 270 udv->u_obj.uo_refs = 1; 271 udv->u_flags = 0; 272 udv->u_device = device; 273 LIST_INSERT_HEAD(&udv_list, udv, u_list); 274 simple_unlock(&udv_lock); 275 276 return(&udv->u_obj); 277 278 } /* while(1) loop */ 279 280 /*NOTREACHED*/ 281 } 282 283 /* 284 * udv_reference 285 * 286 * add a reference to a VM object. Note that the reference count must 287 * already be one (the passed in reference) so there is no chance of the 288 * udv being released or locked out here. 289 * 290 * => caller must call with object unlocked. 291 */ 292 293 static void 294 udv_reference(uobj) 295 struct uvm_object *uobj; 296 { 297 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 298 299 simple_lock(&uobj->vmobjlock); 300 uobj->uo_refs++; 301 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 302 uobj, uobj->uo_refs,0,0); 303 simple_unlock(&uobj->vmobjlock); 304 } 305 306 /* 307 * udv_detach 308 * 309 * remove a reference to a VM object. 310 * 311 * => caller must call with object unlocked and map locked. 312 */ 313 314 static void 315 udv_detach(uobj) 316 struct uvm_object *uobj; 317 { 318 struct uvm_device *udv = (struct uvm_device *) uobj; 319 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 320 321 /* 322 * loop until done 323 */ 324 325 while (1) { 326 simple_lock(&uobj->vmobjlock); 327 328 if (uobj->uo_refs > 1) { 329 uobj->uo_refs--; /* drop ref! */ 330 simple_unlock(&uobj->vmobjlock); 331 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 332 uobj,uobj->uo_refs,0,0); 333 return; 334 } 335 336 #ifdef DIAGNOSTIC 337 if (uobj->uo_npages || uobj->memq.tqh_first) 338 panic("udv_detach: pages in a device object?"); 339 #endif 340 341 /* 342 * now lock udv_lock 343 */ 344 simple_lock(&udv_lock); 345 346 /* 347 * is it being held? if so, wait until others are done. 348 */ 349 if (udv->u_flags & UVM_DEVICE_HOLD) { 350 351 /* 352 * want it 353 */ 354 udv->u_flags |= UVM_DEVICE_WANTED; 355 simple_unlock(&uobj->vmobjlock); 356 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 357 continue; 358 } 359 360 /* 361 * got it! nuke it now. 362 */ 363 364 LIST_REMOVE(udv, u_list); 365 if (udv->u_flags & UVM_DEVICE_WANTED) 366 wakeup(udv); 367 FREE(udv, M_TEMP); 368 break; /* DONE! */ 369 370 } /* while (1) loop */ 371 372 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 373 return; 374 } 375 376 377 /* 378 * udv_flush 379 * 380 * flush pages out of a uvm object. a no-op for devices. 381 */ 382 383 static boolean_t udv_flush(uobj, start, stop, flags) 384 struct uvm_object *uobj; 385 voff_t start, stop; 386 int flags; 387 { 388 389 return(TRUE); 390 } 391 392 /* 393 * udv_fault: non-standard fault routine for device "pages" 394 * 395 * => rather than having a "get" function, we have a fault routine 396 * since we don't return vm_pages we need full control over the 397 * pmap_enter map in 398 * => all the usual fault data structured are locked by the caller 399 * (i.e. maps(read), amap (if any), uobj) 400 * => on return, we unlock all fault data structures 401 * => flags: PGO_ALLPAGES: get all of the pages 402 * PGO_LOCKED: fault data structures are locked 403 * XXX: currently PGO_LOCKED is always required ... consider removing 404 * it as a flag 405 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 406 */ 407 408 static int 409 udv_fault(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags) 410 struct uvm_faultinfo *ufi; 411 vaddr_t vaddr; 412 vm_page_t *pps; 413 int npages, centeridx, flags; 414 vm_fault_t fault_type; 415 vm_prot_t access_type; 416 { 417 struct vm_map_entry *entry = ufi->entry; 418 struct uvm_object *uobj = entry->object.uvm_obj; 419 struct uvm_device *udv = (struct uvm_device *)uobj; 420 vaddr_t curr_va; 421 int curr_offset; 422 paddr_t paddr; 423 int lcv, retval, mdpgno; 424 dev_t device; 425 int (*mapfn) __P((dev_t, int, int)); 426 vm_prot_t mapprot; 427 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 428 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 429 430 /* 431 * XXX: !PGO_LOCKED calls are currently not allowed (or used) 432 */ 433 434 if ((flags & PGO_LOCKED) == 0) 435 panic("udv_fault: !PGO_LOCKED fault"); 436 437 /* 438 * we do not allow device mappings to be mapped copy-on-write 439 * so we kill any attempt to do so here. 440 */ 441 442 if (UVM_ET_ISCOPYONWRITE(entry)) { 443 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 444 entry->etype, 0,0,0); 445 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 446 return(VM_PAGER_ERROR); 447 } 448 449 /* 450 * get device map function. 451 */ 452 device = udv->u_device; 453 mapfn = cdevsw[major(device)].d_mmap; 454 455 /* 456 * now we must determine the offset in udv to use and the VA to 457 * use for pmap_enter. note that we always use orig_map's pmap 458 * for pmap_enter (even if we have a submap). since virtual 459 * addresses in a submap must match the main map, this is ok. 460 */ 461 /* udv offset = (offset from start of entry) + entry's offset */ 462 curr_offset = (int)((vaddr - entry->start) + entry->offset); 463 /* pmap va = vaddr (virtual address of pps[0]) */ 464 curr_va = vaddr; 465 466 /* 467 * loop over the page range entering in as needed 468 */ 469 470 retval = VM_PAGER_OK; 471 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 472 curr_va += PAGE_SIZE) { 473 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 474 continue; 475 476 if (pps[lcv] == PGO_DONTCARE) 477 continue; 478 479 mdpgno = (*mapfn)(device, curr_offset, access_type); 480 if (mdpgno == -1) { 481 retval = VM_PAGER_ERROR; 482 break; 483 } 484 paddr = pmap_phys_address(mdpgno); 485 mapprot = ufi->entry->protection; 486 UVMHIST_LOG(maphist, 487 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%x, at=%d", 488 ufi->orig_map->pmap, curr_va, (int)paddr, mapprot); 489 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 490 mapprot, PMAP_CANFAIL | mapprot) != KERN_SUCCESS) { 491 /* 492 * pmap_enter() didn't have the resource to 493 * enter this mapping. Unlock everything, 494 * wait for the pagedaemon to free up some 495 * pages, and then tell uvm_fault() to start 496 * the fault again. 497 * 498 * XXX Needs some rethinking for the PGO_ALLPAGES 499 * XXX case. 500 */ 501 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 502 uobj, NULL); 503 uvm_wait("udv_fault"); 504 return (VM_PAGER_REFAULT); 505 } 506 } 507 508 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 509 return (retval); 510 } 511 512 /* 513 * udv_asyncget: start async I/O to bring pages into ram 514 * 515 * => caller must lock object(???XXX: see if this is best) 516 * => a no-op for devices 517 */ 518 519 static int 520 udv_asyncget(uobj, offset, npages) 521 struct uvm_object *uobj; 522 voff_t offset; 523 int npages; 524 { 525 526 return(KERN_SUCCESS); 527 } 528 529 /* 530 * udv_put: flush page data to backing store. 531 * 532 * => this function should never be called (since we never have any 533 * page structures to "put") 534 */ 535 536 static int 537 udv_put(uobj, pps, npages, flags) 538 struct uvm_object *uobj; 539 struct vm_page **pps; 540 int npages, flags; 541 { 542 543 panic("udv_put: trying to page out to a device!"); 544 } 545