uvm_device.c revision 1.11
1 /* $NetBSD: uvm_device.c,v 1.11 1998/11/19 05:23:26 mrg Exp $ */ 2 3 /* 4 * XXXCDC: "ROUGH DRAFT" QUALITY UVM PRE-RELEASE FILE! 5 * >>>USE AT YOUR OWN RISK, WORK IS NOT FINISHED<<< 6 */ 7 8 /* 9 * 10 * Copyright (c) 1997 Charles D. Cranor and Washington University. 11 * All rights reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by Charles D. Cranor and 24 * Washington University. 25 * 4. The name of the author may not be used to endorse or promote products 26 * derived from this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 * 39 * from: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp 40 */ 41 42 #include "opt_uvmhist.h" 43 44 /* 45 * uvm_device.c: the device pager. 46 */ 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/conf.h> 51 #include <sys/proc.h> 52 #include <sys/malloc.h> 53 #include <sys/vnode.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_page.h> 57 #include <vm/vm_kern.h> 58 59 #include <uvm/uvm.h> 60 #include <uvm/uvm_device.h> 61 62 /* 63 * private global data structure 64 * 65 * we keep a list of active device objects in the system. 66 */ 67 68 LIST_HEAD(udv_list_struct, uvm_device); 69 static struct udv_list_struct udv_list; 70 static simple_lock_data_t udv_lock; 71 72 /* 73 * functions 74 */ 75 76 static void udv_init __P((void)); 77 struct uvm_object *udv_attach __P((void *, vm_prot_t)); 78 static void udv_reference __P((struct uvm_object *)); 79 static void udv_detach __P((struct uvm_object *)); 80 static int udv_fault __P((struct uvm_faultinfo *, vaddr_t, 81 vm_page_t *, int, int, vm_fault_t, 82 vm_prot_t, int)); 83 static boolean_t udv_flush __P((struct uvm_object *, vaddr_t, 84 vaddr_t, int)); 85 static int udv_asyncget __P((struct uvm_object *, vaddr_t, 86 int)); 87 static int udv_put __P((struct uvm_object *, vm_page_t *, 88 int, boolean_t)); 89 90 /* 91 * master pager structure 92 */ 93 94 struct uvm_pagerops uvm_deviceops = { 95 udv_init, 96 udv_attach, 97 udv_reference, 98 udv_detach, 99 udv_fault, 100 udv_flush, 101 NULL, /* no get function since we have udv_fault */ 102 udv_asyncget, 103 udv_put, 104 NULL, /* no cluster function */ 105 NULL, /* no put cluster function */ 106 NULL, /* no share protect. no share maps for us */ 107 NULL, /* no AIO-DONE function since no async i/o */ 108 NULL, /* no releasepg function since no normal pages */ 109 }; 110 111 /* 112 * the ops! 113 */ 114 115 /* 116 * udv_init 117 * 118 * init pager private data structures. 119 */ 120 121 void 122 udv_init() 123 { 124 125 LIST_INIT(&udv_list); 126 simple_lock_init(&udv_lock); 127 } 128 129 /* 130 * udv_attach 131 * 132 * get a VM object that is associated with a device. allocate a new 133 * one if needed. 134 * 135 * => caller must _not_ already be holding the lock on the uvm_object. 136 * => in fact, nothing should be locked so that we can sleep here. 137 */ 138 struct uvm_object * 139 udv_attach(arg, accessprot) 140 void *arg; 141 vm_prot_t accessprot; 142 { 143 dev_t device = *((dev_t *) arg); 144 struct uvm_device *udv, *lcv; 145 int (*mapfn) __P((dev_t, int, int)); 146 UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); 147 148 UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0); 149 150 /* 151 * before we do anything, ensure this device supports mmap 152 */ 153 154 mapfn = cdevsw[major(device)].d_mmap; 155 if (mapfn == NULL || 156 mapfn == (int (*) __P((dev_t, int, int))) enodev || 157 mapfn == (int (*) __P((dev_t, int, int))) nullop) 158 return(NULL); 159 160 /* 161 * keep looping until we get it 162 */ 163 164 while (1) { 165 166 /* 167 * first, attempt to find it on the main list 168 */ 169 170 simple_lock(&udv_lock); 171 for (lcv = udv_list.lh_first ; lcv != NULL ; lcv = lcv->u_list.le_next) { 172 if (device == lcv->u_device) 173 break; 174 } 175 176 /* 177 * got it on main list. put a hold on it and unlock udv_lock. 178 */ 179 180 if (lcv) { 181 182 /* 183 * if someone else has a hold on it, sleep and start 184 * over again. 185 */ 186 187 if (lcv->u_flags & UVM_DEVICE_HOLD) { 188 lcv->u_flags |= UVM_DEVICE_WANTED; 189 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 190 "udv_attach",0); 191 continue; 192 } 193 194 /* we are now holding it */ 195 lcv->u_flags |= UVM_DEVICE_HOLD; 196 simple_unlock(&udv_lock); 197 198 /* 199 * bump reference count, unhold, return. 200 */ 201 202 simple_lock(&lcv->u_obj.vmobjlock); 203 lcv->u_obj.uo_refs++; 204 simple_unlock(&lcv->u_obj.vmobjlock); 205 206 simple_lock(&udv_lock); 207 if (lcv->u_flags & UVM_DEVICE_WANTED) 208 wakeup(lcv); 209 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 210 simple_unlock(&udv_lock); 211 return(&lcv->u_obj); 212 } 213 214 /* 215 * did not find it on main list. need to malloc a new one. 216 */ 217 218 simple_unlock(&udv_lock); 219 /* NOTE: we could sleep in the following malloc() */ 220 MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, M_WAITOK); 221 simple_lock(&udv_lock); 222 223 /* 224 * now we have to double check to make sure no one added it 225 * to the list while we were sleeping... 226 */ 227 228 for (lcv = udv_list.lh_first ; lcv != NULL ; 229 lcv = lcv->u_list.le_next) { 230 if (device == lcv->u_device) 231 break; 232 } 233 234 /* 235 * did we lose a race to someone else? free our memory and retry. 236 */ 237 238 if (lcv) { 239 simple_unlock(&udv_lock); 240 FREE(udv, M_TEMP); 241 continue; 242 } 243 244 /* 245 * we have it! init the data structures, add to list 246 * and return. 247 */ 248 249 simple_lock_init(&udv->u_obj.vmobjlock); 250 udv->u_obj.pgops = &uvm_deviceops; 251 TAILQ_INIT(&udv->u_obj.memq); /* not used, but be safe */ 252 udv->u_obj.uo_npages = 0; 253 udv->u_obj.uo_refs = 1; 254 udv->u_flags = 0; 255 udv->u_device = device; 256 LIST_INSERT_HEAD(&udv_list, udv, u_list); 257 simple_unlock(&udv_lock); 258 259 return(&udv->u_obj); 260 261 } /* while(1) loop */ 262 263 /*NOTREACHED*/ 264 } 265 266 /* 267 * udv_reference 268 * 269 * add a reference to a VM object. Note that the reference count must 270 * already be one (the passed in reference) so there is no chance of the 271 * udv being released or locked out here. 272 * 273 * => caller must call with object unlocked. 274 */ 275 276 static void 277 udv_reference(uobj) 278 struct uvm_object *uobj; 279 { 280 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 281 282 simple_lock(&uobj->vmobjlock); 283 uobj->uo_refs++; 284 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 285 uobj, uobj->uo_refs,0,0); 286 simple_unlock(&uobj->vmobjlock); 287 } 288 289 /* 290 * udv_detach 291 * 292 * remove a reference to a VM object. 293 * 294 * => caller must call with object unlocked and map locked. 295 */ 296 297 static void 298 udv_detach(uobj) 299 struct uvm_object *uobj; 300 { 301 struct uvm_device *udv = (struct uvm_device *) uobj; 302 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 303 304 /* 305 * loop until done 306 */ 307 308 while (1) { 309 simple_lock(&uobj->vmobjlock); 310 311 if (uobj->uo_refs > 1) { 312 uobj->uo_refs--; /* drop ref! */ 313 simple_unlock(&uobj->vmobjlock); 314 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 315 uobj,uobj->uo_refs,0,0); 316 return; 317 } 318 319 #ifdef DIAGNOSTIC 320 if (uobj->uo_npages || uobj->memq.tqh_first) 321 panic("udv_detach: pages in a device object?"); 322 #endif 323 324 /* 325 * now lock udv_lock 326 */ 327 simple_lock(&udv_lock); 328 329 /* 330 * is it being held? if so, wait until others are done. 331 */ 332 if (udv->u_flags & UVM_DEVICE_HOLD) { 333 334 /* 335 * want it 336 */ 337 udv->u_flags |= UVM_DEVICE_WANTED; 338 simple_unlock(&uobj->vmobjlock); 339 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 340 continue; 341 } 342 343 /* 344 * got it! nuke it now. 345 */ 346 347 LIST_REMOVE(udv, u_list); 348 if (udv->u_flags & UVM_DEVICE_WANTED) 349 wakeup(udv); 350 FREE(udv, M_TEMP); 351 break; /* DONE! */ 352 353 } /* while (1) loop */ 354 355 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 356 return; 357 } 358 359 360 /* 361 * udv_flush 362 * 363 * flush pages out of a uvm object. a no-op for devices. 364 */ 365 366 static boolean_t udv_flush(uobj, start, stop, flags) 367 struct uvm_object *uobj; 368 vaddr_t start, stop; 369 int flags; 370 { 371 372 return(TRUE); 373 } 374 375 /* 376 * udv_fault: non-standard fault routine for device "pages" 377 * 378 * => rather than having a "get" function, we have a fault routine 379 * since we don't return vm_pages we need full control over the 380 * pmap_enter map in 381 * => all the usual fault data structured are locked by the caller 382 * (i.e. maps(read), amap (if any), uobj) 383 * => on return, we unlock all fault data structures 384 * => flags: PGO_ALLPAGES: get all of the pages 385 * PGO_LOCKED: fault data structures are locked 386 * XXX: currently PGO_LOCKED is always required ... consider removing 387 * it as a flag 388 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 389 */ 390 391 static int 392 udv_fault(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags) 393 struct uvm_faultinfo *ufi; 394 vaddr_t vaddr; 395 vm_page_t *pps; 396 int npages, centeridx, flags; 397 vm_fault_t fault_type; 398 vm_prot_t access_type; 399 { 400 struct vm_map_entry *entry = ufi->entry; 401 struct uvm_object *uobj = entry->object.uvm_obj; 402 struct uvm_device *udv = (struct uvm_device *)uobj; 403 vaddr_t curr_offset, curr_va; 404 paddr_t paddr; 405 int lcv, retval, mdpgno; 406 dev_t device; 407 int (*mapfn) __P((dev_t, int, int)); 408 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 409 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 410 411 /* 412 * XXX: !PGO_LOCKED calls are currently not allowed (or used) 413 */ 414 415 if ((flags & PGO_LOCKED) == 0) 416 panic("udv_fault: !PGO_LOCKED fault"); 417 418 /* 419 * we do not allow device mappings to be mapped copy-on-write 420 * so we kill any attempt to do so here. 421 */ 422 423 if (UVM_ET_ISCOPYONWRITE(entry)) { 424 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 425 entry->etype, 0,0,0); 426 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 427 return(VM_PAGER_ERROR); 428 } 429 430 /* 431 * get device map function. 432 */ 433 device = udv->u_device; 434 mapfn = cdevsw[major(device)].d_mmap; 435 436 /* 437 * now we must determine the offset in udv to use and the VA to 438 * use for pmap_enter. note that we always use orig_map's pmap 439 * for pmap_enter (even if we have a submap). since virtual 440 * addresses in a submap must match the main map, this is ok. 441 */ 442 /* udv offset = (offset from start of entry) + entry's offset */ 443 curr_offset = (vaddr - entry->start) + entry->offset; 444 /* pmap va = vaddr (virtual address of pps[0]) */ 445 curr_va = vaddr; 446 447 /* 448 * loop over the page range entering in as needed 449 */ 450 451 retval = VM_PAGER_OK; 452 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 453 curr_va += PAGE_SIZE) { 454 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 455 continue; 456 457 if (pps[lcv] == PGO_DONTCARE) 458 continue; 459 460 mdpgno = (*mapfn)(device, (int)curr_offset, access_type); 461 if (mdpgno == -1) { 462 retval = VM_PAGER_ERROR; 463 break; 464 } 465 paddr = pmap_phys_address(mdpgno); 466 UVMHIST_LOG(maphist, 467 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%x, at=%d", 468 ufi->orig_map->pmap, curr_va, (int)paddr, access_type); 469 pmap_enter(ufi->orig_map->pmap, curr_va, paddr, access_type, 0); 470 471 } 472 473 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 474 return(retval); 475 } 476 477 /* 478 * udv_asyncget: start async I/O to bring pages into ram 479 * 480 * => caller must lock object(???XXX: see if this is best) 481 * => a no-op for devices 482 */ 483 484 static int 485 udv_asyncget(uobj, offset, npages) 486 struct uvm_object *uobj; 487 vaddr_t offset; 488 int npages; 489 { 490 491 return(KERN_SUCCESS); 492 } 493 494 /* 495 * udv_put: flush page data to backing store. 496 * 497 * => this function should never be called (since we never have any 498 * page structures to "put") 499 */ 500 501 static int 502 udv_put(uobj, pps, npages, flags) 503 struct uvm_object *uobj; 504 struct vm_page **pps; 505 int npages, flags; 506 { 507 508 panic("udv_put: trying to page out to a device!"); 509 } 510
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