1 /* $NetBSD: uvm_device.c,v 1.28 2000/06/27 17:29:20 mrg 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 <uvm/uvm.h> 51 #include <uvm/uvm_device.h> 52 53 /* 54 * private global data structure 55 * 56 * we keep a list of active device objects in the system. 57 */ 58 59 LIST_HEAD(udv_list_struct, uvm_device); 60 static struct udv_list_struct udv_list; 61 static simple_lock_data_t udv_lock; 62 63 /* 64 * functions 65 */ 66 67 static void udv_init __P((void)); 68 static void udv_reference __P((struct uvm_object *)); 69 static void udv_detach __P((struct uvm_object *)); 70 static int udv_fault __P((struct uvm_faultinfo *, vaddr_t, 71 vm_page_t *, int, int, vm_fault_t, 72 vm_prot_t, int)); 73 static int udv_asyncget __P((struct uvm_object *, voff_t, 74 int)); 75 static boolean_t udv_flush __P((struct uvm_object *, voff_t, voff_t, 76 int)); 77 static int udv_put __P((struct uvm_object *, vm_page_t *, 78 int, boolean_t)); 79 80 /* 81 * master pager structure 82 */ 83 84 struct uvm_pagerops uvm_deviceops = { 85 udv_init, 86 udv_reference, 87 udv_detach, 88 udv_fault, 89 udv_flush, 90 NULL, /* no get function since we have udv_fault */ 91 udv_asyncget, 92 udv_put, 93 NULL, /* no cluster function */ 94 NULL, /* no put cluster function */ 95 NULL, /* no AIO-DONE function since no async i/o */ 96 NULL, /* no releasepg function since no normal pages */ 97 }; 98 99 /* 100 * the ops! 101 */ 102 103 /* 104 * udv_init 105 * 106 * init pager private data structures. 107 */ 108 109 void 110 udv_init() 111 { 112 113 LIST_INIT(&udv_list); 114 simple_lock_init(&udv_lock); 115 } 116 117 /* 118 * udv_attach 119 * 120 * get a VM object that is associated with a device. allocate a new 121 * one if needed. 122 * 123 * => caller must _not_ already be holding the lock on the uvm_object. 124 * => in fact, nothing should be locked so that we can sleep here. 125 */ 126 struct uvm_object * 127 udv_attach(arg, accessprot, off, size) 128 void *arg; 129 vm_prot_t accessprot; 130 voff_t off; /* used only for access check */ 131 vsize_t size; /* used only for access check */ 132 { 133 dev_t device = *((dev_t *) arg); 134 struct uvm_device *udv, *lcv; 135 paddr_t (*mapfn) __P((dev_t, off_t, int)); 136 UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); 137 138 UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0); 139 140 /* 141 * before we do anything, ensure this device supports mmap 142 */ 143 144 mapfn = cdevsw[major(device)].d_mmap; 145 if (mapfn == NULL || 146 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) enodev || 147 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) nullop) 148 return(NULL); 149 150 /* 151 * Negative offsets on the object are not allowed. 152 */ 153 if (off < 0) 154 return(NULL); 155 156 /* 157 * Check that the specified range of the device allows the 158 * desired protection. 159 * 160 * XXX assumes VM_PROT_* == PROT_* 161 * XXX clobbers off and size, but nothing else here needs them. 162 */ 163 164 while (size != 0) { 165 if ((*mapfn)(device, off, accessprot) == -1) 166 return (NULL); 167 off += PAGE_SIZE; size -= PAGE_SIZE; 168 } 169 170 /* 171 * keep looping until we get it 172 */ 173 174 while (1) { 175 176 /* 177 * first, attempt to find it on the main list 178 */ 179 180 simple_lock(&udv_lock); 181 for (lcv = udv_list.lh_first ; lcv != NULL ; lcv = lcv->u_list.le_next) { 182 if (device == lcv->u_device) 183 break; 184 } 185 186 /* 187 * got it on main list. put a hold on it and unlock udv_lock. 188 */ 189 190 if (lcv) { 191 192 /* 193 * if someone else has a hold on it, sleep and start 194 * over again. 195 */ 196 197 if (lcv->u_flags & UVM_DEVICE_HOLD) { 198 lcv->u_flags |= UVM_DEVICE_WANTED; 199 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 200 "udv_attach",0); 201 continue; 202 } 203 204 /* we are now holding it */ 205 lcv->u_flags |= UVM_DEVICE_HOLD; 206 simple_unlock(&udv_lock); 207 208 /* 209 * bump reference count, unhold, return. 210 */ 211 212 simple_lock(&lcv->u_obj.vmobjlock); 213 lcv->u_obj.uo_refs++; 214 simple_unlock(&lcv->u_obj.vmobjlock); 215 216 simple_lock(&udv_lock); 217 if (lcv->u_flags & UVM_DEVICE_WANTED) 218 wakeup(lcv); 219 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 220 simple_unlock(&udv_lock); 221 return(&lcv->u_obj); 222 } 223 224 /* 225 * did not find it on main list. need to malloc a new one. 226 */ 227 228 simple_unlock(&udv_lock); 229 /* NOTE: we could sleep in the following malloc() */ 230 MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, M_WAITOK); 231 simple_lock(&udv_lock); 232 233 /* 234 * now we have to double check to make sure no one added it 235 * to the list while we were sleeping... 236 */ 237 238 for (lcv = udv_list.lh_first ; lcv != NULL ; 239 lcv = lcv->u_list.le_next) { 240 if (device == lcv->u_device) 241 break; 242 } 243 244 /* 245 * did we lose a race to someone else? free our memory and retry. 246 */ 247 248 if (lcv) { 249 simple_unlock(&udv_lock); 250 FREE(udv, M_TEMP); 251 continue; 252 } 253 254 /* 255 * we have it! init the data structures, add to list 256 * and return. 257 */ 258 259 simple_lock_init(&udv->u_obj.vmobjlock); 260 udv->u_obj.pgops = &uvm_deviceops; 261 TAILQ_INIT(&udv->u_obj.memq); /* not used, but be safe */ 262 udv->u_obj.uo_npages = 0; 263 udv->u_obj.uo_refs = 1; 264 udv->u_flags = 0; 265 udv->u_device = device; 266 LIST_INSERT_HEAD(&udv_list, udv, u_list); 267 simple_unlock(&udv_lock); 268 269 return(&udv->u_obj); 270 271 } /* while(1) loop */ 272 273 /*NOTREACHED*/ 274 } 275 276 /* 277 * udv_reference 278 * 279 * add a reference to a VM object. Note that the reference count must 280 * already be one (the passed in reference) so there is no chance of the 281 * udv being released or locked out here. 282 * 283 * => caller must call with object unlocked. 284 */ 285 286 static void 287 udv_reference(uobj) 288 struct uvm_object *uobj; 289 { 290 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 291 292 simple_lock(&uobj->vmobjlock); 293 uobj->uo_refs++; 294 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 295 uobj, uobj->uo_refs,0,0); 296 simple_unlock(&uobj->vmobjlock); 297 } 298 299 /* 300 * udv_detach 301 * 302 * remove a reference to a VM object. 303 * 304 * => caller must call with object unlocked and map locked. 305 */ 306 307 static void 308 udv_detach(uobj) 309 struct uvm_object *uobj; 310 { 311 struct uvm_device *udv = (struct uvm_device *) uobj; 312 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 313 314 315 /* 316 * loop until done 317 */ 318 again: 319 simple_lock(&uobj->vmobjlock); 320 321 if (uobj->uo_refs > 1) { 322 uobj->uo_refs--; /* drop ref! */ 323 simple_unlock(&uobj->vmobjlock); 324 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 325 uobj,uobj->uo_refs,0,0); 326 return; 327 } 328 329 #ifdef DIAGNOSTIC 330 if (uobj->uo_npages || !TAILQ_EMPTY(&uobj->memq)) 331 panic("udv_detach: pages in a device object?"); 332 #endif 333 334 /* 335 * now lock udv_lock 336 */ 337 simple_lock(&udv_lock); 338 339 /* 340 * is it being held? if so, wait until others are done. 341 */ 342 if (udv->u_flags & UVM_DEVICE_HOLD) { 343 udv->u_flags |= UVM_DEVICE_WANTED; 344 simple_unlock(&uobj->vmobjlock); 345 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 346 goto again; 347 } 348 349 /* 350 * got it! nuke it now. 351 */ 352 LIST_REMOVE(udv, u_list); 353 if (udv->u_flags & UVM_DEVICE_WANTED) 354 wakeup(udv); 355 simple_unlock(&udv_lock); 356 simple_unlock(&uobj->vmobjlock); 357 FREE(udv, M_TEMP); 358 359 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 360 return; 361 } 362 363 364 /* 365 * udv_flush 366 * 367 * flush pages out of a uvm object. a no-op for devices. 368 */ 369 370 static boolean_t udv_flush(uobj, start, stop, flags) 371 struct uvm_object *uobj; 372 voff_t start, stop; 373 int flags; 374 { 375 376 return(TRUE); 377 } 378 379 /* 380 * udv_fault: non-standard fault routine for device "pages" 381 * 382 * => rather than having a "get" function, we have a fault routine 383 * since we don't return vm_pages we need full control over the 384 * pmap_enter map in 385 * => all the usual fault data structured are locked by the caller 386 * (i.e. maps(read), amap (if any), uobj) 387 * => on return, we unlock all fault data structures 388 * => flags: PGO_ALLPAGES: get all of the pages 389 * PGO_LOCKED: fault data structures are locked 390 * XXX: currently PGO_LOCKED is always required ... consider removing 391 * it as a flag 392 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 393 */ 394 395 static int 396 udv_fault(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags) 397 struct uvm_faultinfo *ufi; 398 vaddr_t vaddr; 399 vm_page_t *pps; 400 int npages, centeridx, flags; 401 vm_fault_t fault_type; 402 vm_prot_t access_type; 403 { 404 struct vm_map_entry *entry = ufi->entry; 405 struct uvm_object *uobj = entry->object.uvm_obj; 406 struct uvm_device *udv = (struct uvm_device *)uobj; 407 vaddr_t curr_va; 408 off_t curr_offset; 409 paddr_t paddr, mdpgno; 410 int lcv, retval; 411 dev_t device; 412 paddr_t (*mapfn) __P((dev_t, off_t, int)); 413 vm_prot_t mapprot; 414 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 415 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 416 417 /* 418 * XXX: !PGO_LOCKED calls are currently not allowed (or used) 419 */ 420 421 if ((flags & PGO_LOCKED) == 0) 422 panic("udv_fault: !PGO_LOCKED fault"); 423 424 /* 425 * we do not allow device mappings to be mapped copy-on-write 426 * so we kill any attempt to do so here. 427 */ 428 429 if (UVM_ET_ISCOPYONWRITE(entry)) { 430 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 431 entry->etype, 0,0,0); 432 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 433 return(VM_PAGER_ERROR); 434 } 435 436 /* 437 * get device map function. 438 */ 439 device = udv->u_device; 440 mapfn = cdevsw[major(device)].d_mmap; 441 442 /* 443 * now we must determine the offset in udv to use and the VA to 444 * use for pmap_enter. note that we always use orig_map's pmap 445 * for pmap_enter (even if we have a submap). since virtual 446 * addresses in a submap must match the main map, this is ok. 447 */ 448 /* udv offset = (offset from start of entry) + entry's offset */ 449 curr_offset = entry->offset + (vaddr - entry->start); 450 /* pmap va = vaddr (virtual address of pps[0]) */ 451 curr_va = vaddr; 452 453 /* 454 * loop over the page range entering in as needed 455 */ 456 457 retval = VM_PAGER_OK; 458 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 459 curr_va += PAGE_SIZE) { 460 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 461 continue; 462 463 if (pps[lcv] == PGO_DONTCARE) 464 continue; 465 466 mdpgno = (*mapfn)(device, curr_offset, access_type); 467 if (mdpgno == -1) { 468 retval = VM_PAGER_ERROR; 469 break; 470 } 471 paddr = pmap_phys_address(mdpgno); 472 mapprot = ufi->entry->protection; 473 UVMHIST_LOG(maphist, 474 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d", 475 ufi->orig_map->pmap, curr_va, paddr, mapprot); 476 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 477 mapprot, PMAP_CANFAIL | mapprot) != KERN_SUCCESS) { 478 /* 479 * pmap_enter() didn't have the resource to 480 * enter this mapping. Unlock everything, 481 * wait for the pagedaemon to free up some 482 * pages, and then tell uvm_fault() to start 483 * the fault again. 484 * 485 * XXX Needs some rethinking for the PGO_ALLPAGES 486 * XXX case. 487 */ 488 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 489 uobj, NULL); 490 uvm_wait("udv_fault"); 491 return (VM_PAGER_REFAULT); 492 } 493 } 494 495 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 496 return (retval); 497 } 498 499 /* 500 * udv_asyncget: start async I/O to bring pages into ram 501 * 502 * => caller must lock object(???XXX: see if this is best) 503 * => a no-op for devices 504 */ 505 506 static int 507 udv_asyncget(uobj, offset, npages) 508 struct uvm_object *uobj; 509 voff_t offset; 510 int npages; 511 { 512 513 return(KERN_SUCCESS); 514 } 515 516 /* 517 * udv_put: flush page data to backing store. 518 * 519 * => this function should never be called (since we never have any 520 * page structures to "put") 521 */ 522 523 static int 524 udv_put(uobj, pps, npages, flags) 525 struct uvm_object *uobj; 526 struct vm_page **pps; 527 int npages, flags; 528 { 529 530 panic("udv_put: trying to page out to a device!"); 531 } 532