1 /* $NetBSD: uvm_bio.c,v 1.80 2013/10/25 20:23:33 martin Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Chuck Silvers. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 */ 31 32 /* 33 * uvm_bio.c: buffered i/o object mapping cache 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.80 2013/10/25 20:23:33 martin Exp $"); 38 39 #include "opt_uvmhist.h" 40 #include "opt_ubc.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/kmem.h> 45 #include <sys/kernel.h> 46 #include <sys/proc.h> 47 #include <sys/vnode.h> 48 49 #include <uvm/uvm.h> 50 51 /* 52 * global data structures 53 */ 54 55 /* 56 * local functions 57 */ 58 59 static int ubc_fault(struct uvm_faultinfo *, vaddr_t, struct vm_page **, 60 int, int, vm_prot_t, int); 61 static struct ubc_map *ubc_find_mapping(struct uvm_object *, voff_t); 62 63 /* 64 * local data structues 65 */ 66 67 #define UBC_HASH(uobj, offset) \ 68 (((((u_long)(uobj)) >> 8) + (((u_long)(offset)) >> PAGE_SHIFT)) & \ 69 ubc_object.hashmask) 70 71 #define UBC_QUEUE(offset) \ 72 (&ubc_object.inactive[(((u_long)(offset)) >> ubc_winshift) & \ 73 (UBC_NQUEUES - 1)]) 74 75 #define UBC_UMAP_ADDR(u) \ 76 (vaddr_t)(ubc_object.kva + (((u) - ubc_object.umap) << ubc_winshift)) 77 78 79 #define UMAP_PAGES_LOCKED 0x0001 80 #define UMAP_MAPPING_CACHED 0x0002 81 82 struct ubc_map { 83 struct uvm_object * uobj; /* mapped object */ 84 voff_t offset; /* offset into uobj */ 85 voff_t writeoff; /* write offset */ 86 vsize_t writelen; /* write len */ 87 int refcount; /* refcount on mapping */ 88 int flags; /* extra state */ 89 int advice; 90 91 LIST_ENTRY(ubc_map) hash; /* hash table */ 92 TAILQ_ENTRY(ubc_map) inactive; /* inactive queue */ 93 LIST_ENTRY(ubc_map) list; /* per-object list */ 94 }; 95 96 static struct ubc_object { 97 struct uvm_object uobj; /* glue for uvm_map() */ 98 char *kva; /* where ubc_object is mapped */ 99 struct ubc_map *umap; /* array of ubc_map's */ 100 101 LIST_HEAD(, ubc_map) *hash; /* hashtable for cached ubc_map's */ 102 u_long hashmask; /* mask for hashtable */ 103 104 TAILQ_HEAD(ubc_inactive_head, ubc_map) *inactive; 105 /* inactive queues for ubc_map's */ 106 } ubc_object; 107 108 const struct uvm_pagerops ubc_pager = { 109 .pgo_fault = ubc_fault, 110 /* ... rest are NULL */ 111 }; 112 113 int ubc_nwins = UBC_NWINS; 114 int ubc_winshift = UBC_WINSHIFT; 115 int ubc_winsize; 116 #if defined(PMAP_PREFER) 117 int ubc_nqueues; 118 #define UBC_NQUEUES ubc_nqueues 119 #else 120 #define UBC_NQUEUES 1 121 #endif 122 123 #if defined(UBC_STATS) 124 125 #define UBC_EVCNT_DEFINE(name) \ 126 struct evcnt ubc_evcnt_##name = \ 127 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "ubc", #name); \ 128 EVCNT_ATTACH_STATIC(ubc_evcnt_##name); 129 #define UBC_EVCNT_INCR(name) ubc_evcnt_##name.ev_count++ 130 131 #else /* defined(UBC_STATS) */ 132 133 #define UBC_EVCNT_DEFINE(name) /* nothing */ 134 #define UBC_EVCNT_INCR(name) /* nothing */ 135 136 #endif /* defined(UBC_STATS) */ 137 138 UBC_EVCNT_DEFINE(wincachehit) 139 UBC_EVCNT_DEFINE(wincachemiss) 140 UBC_EVCNT_DEFINE(faultbusy) 141 142 /* 143 * ubc_init 144 * 145 * init pager private data structures. 146 */ 147 148 void 149 ubc_init(void) 150 { 151 struct ubc_map *umap; 152 vaddr_t va; 153 int i; 154 155 /* 156 * Make sure ubc_winshift is sane. 157 */ 158 if (ubc_winshift < PAGE_SHIFT) 159 ubc_winshift = PAGE_SHIFT; 160 161 /* 162 * init ubc_object. 163 * alloc and init ubc_map's. 164 * init inactive queues. 165 * alloc and init hashtable. 166 * map in ubc_object. 167 */ 168 169 uvm_obj_init(&ubc_object.uobj, &ubc_pager, true, UVM_OBJ_KERN); 170 171 ubc_object.umap = kmem_zalloc(ubc_nwins * sizeof(struct ubc_map), 172 KM_SLEEP); 173 if (ubc_object.umap == NULL) 174 panic("ubc_init: failed to allocate ubc_map"); 175 176 if (ubc_winshift < PAGE_SHIFT) { 177 ubc_winshift = PAGE_SHIFT; 178 } 179 va = (vaddr_t)1L; 180 #ifdef PMAP_PREFER 181 PMAP_PREFER(0, &va, 0, 0); /* kernel is never topdown */ 182 ubc_nqueues = va >> ubc_winshift; 183 if (ubc_nqueues == 0) { 184 ubc_nqueues = 1; 185 } 186 #endif 187 ubc_winsize = 1 << ubc_winshift; 188 ubc_object.inactive = kmem_alloc(UBC_NQUEUES * 189 sizeof(struct ubc_inactive_head), KM_SLEEP); 190 if (ubc_object.inactive == NULL) 191 panic("ubc_init: failed to allocate inactive queue heads"); 192 for (i = 0; i < UBC_NQUEUES; i++) { 193 TAILQ_INIT(&ubc_object.inactive[i]); 194 } 195 for (i = 0; i < ubc_nwins; i++) { 196 umap = &ubc_object.umap[i]; 197 TAILQ_INSERT_TAIL(&ubc_object.inactive[i & (UBC_NQUEUES - 1)], 198 umap, inactive); 199 } 200 201 ubc_object.hash = hashinit(ubc_nwins, HASH_LIST, true, 202 &ubc_object.hashmask); 203 for (i = 0; i <= ubc_object.hashmask; i++) { 204 LIST_INIT(&ubc_object.hash[i]); 205 } 206 207 if (uvm_map(kernel_map, (vaddr_t *)&ubc_object.kva, 208 ubc_nwins << ubc_winshift, &ubc_object.uobj, 0, (vsize_t)va, 209 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE, 210 UVM_ADV_RANDOM, UVM_FLAG_NOMERGE)) != 0) { 211 panic("ubc_init: failed to map ubc_object"); 212 } 213 UVMHIST_INIT(ubchist, 300); 214 } 215 216 /* 217 * ubc_fault_page: helper of ubc_fault to handle a single page. 218 * 219 * => Caller has UVM object locked. 220 * => Caller will perform pmap_update(). 221 */ 222 223 static inline int 224 ubc_fault_page(const struct uvm_faultinfo *ufi, const struct ubc_map *umap, 225 struct vm_page *pg, vm_prot_t prot, vm_prot_t access_type, vaddr_t va) 226 { 227 struct uvm_object *uobj; 228 vm_prot_t mask; 229 int error; 230 bool rdonly; 231 232 uobj = pg->uobject; 233 KASSERT(mutex_owned(uobj->vmobjlock)); 234 235 if (pg->flags & PG_WANTED) { 236 wakeup(pg); 237 } 238 KASSERT((pg->flags & PG_FAKE) == 0); 239 if (pg->flags & PG_RELEASED) { 240 mutex_enter(&uvm_pageqlock); 241 uvm_pagefree(pg); 242 mutex_exit(&uvm_pageqlock); 243 return 0; 244 } 245 if (pg->loan_count != 0) { 246 247 /* 248 * Avoid unneeded loan break, if possible. 249 */ 250 251 if ((access_type & VM_PROT_WRITE) == 0) { 252 prot &= ~VM_PROT_WRITE; 253 } 254 if (prot & VM_PROT_WRITE) { 255 struct vm_page *newpg; 256 257 newpg = uvm_loanbreak(pg); 258 if (newpg == NULL) { 259 uvm_page_unbusy(&pg, 1); 260 return ENOMEM; 261 } 262 pg = newpg; 263 } 264 } 265 266 /* 267 * Note that a page whose backing store is partially allocated 268 * is marked as PG_RDONLY. 269 */ 270 271 KASSERT((pg->flags & PG_RDONLY) == 0 || 272 (access_type & VM_PROT_WRITE) == 0 || 273 pg->offset < umap->writeoff || 274 pg->offset + PAGE_SIZE > umap->writeoff + umap->writelen); 275 276 rdonly = ((access_type & VM_PROT_WRITE) == 0 && 277 (pg->flags & PG_RDONLY) != 0) || 278 UVM_OBJ_NEEDS_WRITEFAULT(uobj); 279 mask = rdonly ? ~VM_PROT_WRITE : VM_PROT_ALL; 280 281 error = pmap_enter(ufi->orig_map->pmap, va, VM_PAGE_TO_PHYS(pg), 282 prot & mask, PMAP_CANFAIL | (access_type & mask)); 283 284 mutex_enter(&uvm_pageqlock); 285 uvm_pageactivate(pg); 286 mutex_exit(&uvm_pageqlock); 287 pg->flags &= ~(PG_BUSY|PG_WANTED); 288 UVM_PAGE_OWN(pg, NULL); 289 290 return error; 291 } 292 293 /* 294 * ubc_fault: fault routine for ubc mapping 295 */ 296 297 static int 298 ubc_fault(struct uvm_faultinfo *ufi, vaddr_t ign1, struct vm_page **ign2, 299 int ign3, int ign4, vm_prot_t access_type, int flags) 300 { 301 struct uvm_object *uobj; 302 struct ubc_map *umap; 303 vaddr_t va, eva, ubc_offset, slot_offset; 304 struct vm_page *pgs[ubc_winsize >> PAGE_SHIFT]; 305 int i, error, npages; 306 vm_prot_t prot; 307 308 UVMHIST_FUNC("ubc_fault"); UVMHIST_CALLED(ubchist); 309 310 /* 311 * no need to try with PGO_LOCKED... 312 * we don't need to have the map locked since we know that 313 * no one will mess with it until our reference is released. 314 */ 315 316 if (flags & PGO_LOCKED) { 317 uvmfault_unlockall(ufi, NULL, &ubc_object.uobj); 318 flags &= ~PGO_LOCKED; 319 } 320 321 va = ufi->orig_rvaddr; 322 ubc_offset = va - (vaddr_t)ubc_object.kva; 323 umap = &ubc_object.umap[ubc_offset >> ubc_winshift]; 324 KASSERT(umap->refcount != 0); 325 KASSERT((umap->flags & UMAP_PAGES_LOCKED) == 0); 326 slot_offset = ubc_offset & (ubc_winsize - 1); 327 328 /* 329 * some platforms cannot write to individual bytes atomically, so 330 * software has to do read/modify/write of larger quantities instead. 331 * this means that the access_type for "write" operations 332 * can be VM_PROT_READ, which confuses us mightily. 333 * 334 * deal with this by resetting access_type based on the info 335 * that ubc_alloc() stores for us. 336 */ 337 338 access_type = umap->writelen ? VM_PROT_WRITE : VM_PROT_READ; 339 UVMHIST_LOG(ubchist, "va 0x%lx ubc_offset 0x%lx access_type %d", 340 va, ubc_offset, access_type, 0); 341 342 #ifdef DIAGNOSTIC 343 if ((access_type & VM_PROT_WRITE) != 0) { 344 if (slot_offset < trunc_page(umap->writeoff) || 345 umap->writeoff + umap->writelen <= slot_offset) { 346 panic("ubc_fault: out of range write"); 347 } 348 } 349 #endif 350 351 /* no umap locking needed since we have a ref on the umap */ 352 uobj = umap->uobj; 353 354 if ((access_type & VM_PROT_WRITE) == 0) { 355 npages = (ubc_winsize - slot_offset) >> PAGE_SHIFT; 356 } else { 357 npages = (round_page(umap->offset + umap->writeoff + 358 umap->writelen) - (umap->offset + slot_offset)) 359 >> PAGE_SHIFT; 360 flags |= PGO_PASTEOF; 361 } 362 363 again: 364 memset(pgs, 0, sizeof (pgs)); 365 mutex_enter(uobj->vmobjlock); 366 367 UVMHIST_LOG(ubchist, "slot_offset 0x%x writeoff 0x%x writelen 0x%x ", 368 slot_offset, umap->writeoff, umap->writelen, 0); 369 UVMHIST_LOG(ubchist, "getpages uobj %p offset 0x%x npages %d", 370 uobj, umap->offset + slot_offset, npages, 0); 371 372 error = (*uobj->pgops->pgo_get)(uobj, umap->offset + slot_offset, pgs, 373 &npages, 0, access_type, umap->advice, flags | PGO_NOBLOCKALLOC | 374 PGO_NOTIMESTAMP); 375 UVMHIST_LOG(ubchist, "getpages error %d npages %d", error, npages, 0, 376 0); 377 378 if (error == EAGAIN) { 379 kpause("ubc_fault", false, hz >> 2, NULL); 380 goto again; 381 } 382 if (error) { 383 return error; 384 } 385 386 /* 387 * For virtually-indexed, virtually-tagged caches we should avoid 388 * creating writable mappings when we do not absolutely need them, 389 * since the "compatible alias" trick does not work on such caches. 390 * Otherwise, we can always map the pages writable. 391 */ 392 393 #ifdef PMAP_CACHE_VIVT 394 prot = VM_PROT_READ | access_type; 395 #else 396 prot = VM_PROT_READ | VM_PROT_WRITE; 397 #endif 398 399 va = ufi->orig_rvaddr; 400 eva = ufi->orig_rvaddr + (npages << PAGE_SHIFT); 401 402 UVMHIST_LOG(ubchist, "va 0x%lx eva 0x%lx", va, eva, 0, 0); 403 404 /* 405 * Note: normally all returned pages would have the same UVM object. 406 * However, layered file-systems and e.g. tmpfs, may return pages 407 * which belong to underlying UVM object. In such case, lock is 408 * shared amongst the objects. 409 */ 410 mutex_enter(uobj->vmobjlock); 411 for (i = 0; va < eva; i++, va += PAGE_SIZE) { 412 struct vm_page *pg; 413 414 UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i], 0, 0); 415 pg = pgs[i]; 416 417 if (pg == NULL || pg == PGO_DONTCARE) { 418 continue; 419 } 420 KASSERT(uobj->vmobjlock == pg->uobject->vmobjlock); 421 error = ubc_fault_page(ufi, umap, pg, prot, access_type, va); 422 if (error) { 423 /* 424 * Flush (there might be pages entered), drop the lock, 425 * and perform uvm_wait(). Note: page will re-fault. 426 */ 427 pmap_update(ufi->orig_map->pmap); 428 mutex_exit(uobj->vmobjlock); 429 uvm_wait("ubc_fault"); 430 mutex_enter(uobj->vmobjlock); 431 } 432 } 433 /* Must make VA visible before the unlock. */ 434 pmap_update(ufi->orig_map->pmap); 435 mutex_exit(uobj->vmobjlock); 436 437 return 0; 438 } 439 440 /* 441 * local functions 442 */ 443 444 static struct ubc_map * 445 ubc_find_mapping(struct uvm_object *uobj, voff_t offset) 446 { 447 struct ubc_map *umap; 448 449 LIST_FOREACH(umap, &ubc_object.hash[UBC_HASH(uobj, offset)], hash) { 450 if (umap->uobj == uobj && umap->offset == offset) { 451 return umap; 452 } 453 } 454 return NULL; 455 } 456 457 458 /* 459 * ubc interface functions 460 */ 461 462 /* 463 * ubc_alloc: allocate a file mapping window 464 */ 465 466 void * 467 ubc_alloc(struct uvm_object *uobj, voff_t offset, vsize_t *lenp, int advice, 468 int flags) 469 { 470 vaddr_t slot_offset, va; 471 struct ubc_map *umap; 472 voff_t umap_offset; 473 int error; 474 UVMHIST_FUNC("ubc_alloc"); UVMHIST_CALLED(ubchist); 475 476 UVMHIST_LOG(ubchist, "uobj %p offset 0x%lx len 0x%lx", 477 uobj, offset, *lenp, 0); 478 479 KASSERT(*lenp > 0); 480 umap_offset = (offset & ~((voff_t)ubc_winsize - 1)); 481 slot_offset = (vaddr_t)(offset & ((voff_t)ubc_winsize - 1)); 482 *lenp = MIN(*lenp, ubc_winsize - slot_offset); 483 484 mutex_enter(ubc_object.uobj.vmobjlock); 485 again: 486 /* 487 * The UVM object is already referenced. 488 * Lock order: UBC object -> ubc_map::uobj. 489 */ 490 umap = ubc_find_mapping(uobj, umap_offset); 491 if (umap == NULL) { 492 struct uvm_object *oobj; 493 494 UBC_EVCNT_INCR(wincachemiss); 495 umap = TAILQ_FIRST(UBC_QUEUE(offset)); 496 if (umap == NULL) { 497 kpause("ubc_alloc", false, hz >> 2, 498 ubc_object.uobj.vmobjlock); 499 goto again; 500 } 501 502 va = UBC_UMAP_ADDR(umap); 503 oobj = umap->uobj; 504 505 /* 506 * Remove from old hash (if any), add to new hash. 507 */ 508 509 if (oobj != NULL) { 510 /* 511 * Mapping must be removed before the list entry, 512 * since there is a race with ubc_purge(). 513 */ 514 if (umap->flags & UMAP_MAPPING_CACHED) { 515 umap->flags &= ~UMAP_MAPPING_CACHED; 516 mutex_enter(oobj->vmobjlock); 517 pmap_remove(pmap_kernel(), va, 518 va + ubc_winsize); 519 pmap_update(pmap_kernel()); 520 mutex_exit(oobj->vmobjlock); 521 } 522 LIST_REMOVE(umap, hash); 523 LIST_REMOVE(umap, list); 524 } else { 525 KASSERT((umap->flags & UMAP_MAPPING_CACHED) == 0); 526 } 527 umap->uobj = uobj; 528 umap->offset = umap_offset; 529 LIST_INSERT_HEAD(&ubc_object.hash[UBC_HASH(uobj, umap_offset)], 530 umap, hash); 531 LIST_INSERT_HEAD(&uobj->uo_ubc, umap, list); 532 } else { 533 UBC_EVCNT_INCR(wincachehit); 534 va = UBC_UMAP_ADDR(umap); 535 } 536 537 if (umap->refcount == 0) { 538 TAILQ_REMOVE(UBC_QUEUE(offset), umap, inactive); 539 } 540 541 if (flags & UBC_WRITE) { 542 KASSERTMSG(umap->writeoff == 0 && umap->writelen == 0, 543 "ubc_alloc: concurrent writes to uobj %p", uobj); 544 umap->writeoff = slot_offset; 545 umap->writelen = *lenp; 546 } 547 548 umap->refcount++; 549 umap->advice = advice; 550 mutex_exit(ubc_object.uobj.vmobjlock); 551 UVMHIST_LOG(ubchist, "umap %p refs %d va %p flags 0x%x", 552 umap, umap->refcount, va, flags); 553 554 if (flags & UBC_FAULTBUSY) { 555 int npages = (*lenp + PAGE_SIZE - 1) >> PAGE_SHIFT; 556 struct vm_page *pgs[npages]; 557 int gpflags = 558 PGO_SYNCIO|PGO_OVERWRITE|PGO_PASTEOF|PGO_NOBLOCKALLOC| 559 PGO_NOTIMESTAMP; 560 int i; 561 KDASSERT(flags & UBC_WRITE); 562 KASSERT(umap->refcount == 1); 563 564 UBC_EVCNT_INCR(faultbusy); 565 again_faultbusy: 566 mutex_enter(uobj->vmobjlock); 567 if (umap->flags & UMAP_MAPPING_CACHED) { 568 umap->flags &= ~UMAP_MAPPING_CACHED; 569 pmap_remove(pmap_kernel(), va, va + ubc_winsize); 570 } 571 memset(pgs, 0, sizeof(pgs)); 572 573 error = (*uobj->pgops->pgo_get)(uobj, trunc_page(offset), pgs, 574 &npages, 0, VM_PROT_READ | VM_PROT_WRITE, advice, gpflags); 575 UVMHIST_LOG(ubchist, "faultbusy getpages %d", error, 0, 0, 0); 576 if (error) { 577 goto out; 578 } 579 for (i = 0; i < npages; i++) { 580 struct vm_page *pg = pgs[i]; 581 582 KASSERT(pg->uobject == uobj); 583 if (pg->loan_count != 0) { 584 mutex_enter(uobj->vmobjlock); 585 if (pg->loan_count != 0) { 586 pg = uvm_loanbreak(pg); 587 } 588 if (pg == NULL) { 589 pmap_kremove(va, ubc_winsize); 590 pmap_update(pmap_kernel()); 591 uvm_page_unbusy(pgs, npages); 592 mutex_exit(uobj->vmobjlock); 593 uvm_wait("ubc_alloc"); 594 goto again_faultbusy; 595 } 596 mutex_exit(uobj->vmobjlock); 597 pgs[i] = pg; 598 } 599 pmap_kenter_pa(va + slot_offset + (i << PAGE_SHIFT), 600 VM_PAGE_TO_PHYS(pg), 601 VM_PROT_READ | VM_PROT_WRITE, 0); 602 } 603 pmap_update(pmap_kernel()); 604 umap->flags |= UMAP_PAGES_LOCKED; 605 } else { 606 KASSERT((umap->flags & UMAP_PAGES_LOCKED) == 0); 607 } 608 609 out: 610 return (void *)(va + slot_offset); 611 } 612 613 /* 614 * ubc_release: free a file mapping window. 615 */ 616 617 void 618 ubc_release(void *va, int flags) 619 { 620 struct ubc_map *umap; 621 struct uvm_object *uobj; 622 vaddr_t umapva; 623 bool unmapped; 624 UVMHIST_FUNC("ubc_release"); UVMHIST_CALLED(ubchist); 625 626 UVMHIST_LOG(ubchist, "va %p", va, 0, 0, 0); 627 umap = &ubc_object.umap[((char *)va - ubc_object.kva) >> ubc_winshift]; 628 umapva = UBC_UMAP_ADDR(umap); 629 uobj = umap->uobj; 630 KASSERT(uobj != NULL); 631 632 if (umap->flags & UMAP_PAGES_LOCKED) { 633 const voff_t slot_offset = umap->writeoff; 634 const voff_t endoff = umap->writeoff + umap->writelen; 635 const voff_t zerolen = round_page(endoff) - endoff; 636 const u_int npages = (round_page(endoff) - 637 trunc_page(slot_offset)) >> PAGE_SHIFT; 638 struct vm_page *pgs[npages]; 639 640 KASSERT((umap->flags & UMAP_MAPPING_CACHED) == 0); 641 if (zerolen) { 642 memset((char *)umapva + endoff, 0, zerolen); 643 } 644 umap->flags &= ~UMAP_PAGES_LOCKED; 645 mutex_enter(uobj->vmobjlock); 646 mutex_enter(&uvm_pageqlock); 647 for (u_int i = 0; i < npages; i++) { 648 paddr_t pa; 649 bool rv __diagused; 650 651 rv = pmap_extract(pmap_kernel(), 652 umapva + slot_offset + (i << PAGE_SHIFT), &pa); 653 KASSERT(rv); 654 pgs[i] = PHYS_TO_VM_PAGE(pa); 655 pgs[i]->flags &= ~(PG_FAKE|PG_CLEAN); 656 KASSERT(pgs[i]->loan_count == 0); 657 uvm_pageactivate(pgs[i]); 658 } 659 mutex_exit(&uvm_pageqlock); 660 pmap_kremove(umapva, ubc_winsize); 661 pmap_update(pmap_kernel()); 662 uvm_page_unbusy(pgs, npages); 663 mutex_exit(uobj->vmobjlock); 664 unmapped = true; 665 } else { 666 unmapped = false; 667 } 668 669 mutex_enter(ubc_object.uobj.vmobjlock); 670 umap->writeoff = 0; 671 umap->writelen = 0; 672 umap->refcount--; 673 if (umap->refcount == 0) { 674 if (flags & UBC_UNMAP) { 675 /* 676 * Invalidate any cached mappings if requested. 677 * This is typically used to avoid leaving 678 * incompatible cache aliases around indefinitely. 679 */ 680 mutex_enter(uobj->vmobjlock); 681 pmap_remove(pmap_kernel(), umapva, 682 umapva + ubc_winsize); 683 pmap_update(pmap_kernel()); 684 mutex_exit(uobj->vmobjlock); 685 686 umap->flags &= ~UMAP_MAPPING_CACHED; 687 LIST_REMOVE(umap, hash); 688 LIST_REMOVE(umap, list); 689 umap->uobj = NULL; 690 TAILQ_INSERT_HEAD(UBC_QUEUE(umap->offset), umap, 691 inactive); 692 } else { 693 if (!unmapped) { 694 umap->flags |= UMAP_MAPPING_CACHED; 695 } 696 TAILQ_INSERT_TAIL(UBC_QUEUE(umap->offset), umap, 697 inactive); 698 } 699 } 700 UVMHIST_LOG(ubchist, "umap %p refs %d", umap, umap->refcount, 0, 0); 701 mutex_exit(ubc_object.uobj.vmobjlock); 702 } 703 704 /* 705 * ubc_uiomove: move data to/from an object. 706 */ 707 708 int 709 ubc_uiomove(struct uvm_object *uobj, struct uio *uio, vsize_t todo, int advice, 710 int flags) 711 { 712 const bool overwrite = (flags & UBC_FAULTBUSY) != 0; 713 voff_t off; 714 int error; 715 716 KASSERT(todo <= uio->uio_resid); 717 KASSERT(((flags & UBC_WRITE) != 0 && uio->uio_rw == UIO_WRITE) || 718 ((flags & UBC_READ) != 0 && uio->uio_rw == UIO_READ)); 719 720 off = uio->uio_offset; 721 error = 0; 722 while (todo > 0) { 723 vsize_t bytelen = todo; 724 void *win; 725 726 win = ubc_alloc(uobj, off, &bytelen, advice, flags); 727 if (error == 0) { 728 error = uiomove(win, bytelen, uio); 729 } 730 if (error != 0 && overwrite) { 731 /* 732 * if we haven't initialized the pages yet, 733 * do it now. it's safe to use memset here 734 * because we just mapped the pages above. 735 */ 736 printf("%s: error=%d\n", __func__, error); 737 memset(win, 0, bytelen); 738 } 739 ubc_release(win, flags); 740 off += bytelen; 741 todo -= bytelen; 742 if (error != 0 && (flags & UBC_PARTIALOK) != 0) { 743 break; 744 } 745 } 746 747 return error; 748 } 749 750 /* 751 * ubc_zerorange: set a range of bytes in an object to zero. 752 */ 753 754 void 755 ubc_zerorange(struct uvm_object *uobj, off_t off, size_t len, int flags) 756 { 757 void *win; 758 759 /* 760 * XXXUBC invent kzero() and use it 761 */ 762 763 while (len) { 764 vsize_t bytelen = len; 765 766 win = ubc_alloc(uobj, off, &bytelen, UVM_ADV_NORMAL, UBC_WRITE); 767 memset(win, 0, bytelen); 768 ubc_release(win, flags); 769 770 off += bytelen; 771 len -= bytelen; 772 } 773 } 774 775 /* 776 * ubc_purge: disassociate ubc_map structures from an empty uvm_object. 777 */ 778 779 void 780 ubc_purge(struct uvm_object *uobj) 781 { 782 struct ubc_map *umap; 783 vaddr_t va; 784 785 KASSERT(uobj->uo_npages == 0); 786 787 /* 788 * Safe to check without lock held, as ubc_alloc() removes 789 * the mapping and list entry in the correct order. 790 */ 791 if (__predict_true(LIST_EMPTY(&uobj->uo_ubc))) { 792 return; 793 } 794 mutex_enter(ubc_object.uobj.vmobjlock); 795 while ((umap = LIST_FIRST(&uobj->uo_ubc)) != NULL) { 796 KASSERT(umap->refcount == 0); 797 for (va = 0; va < ubc_winsize; va += PAGE_SIZE) { 798 KASSERT(!pmap_extract(pmap_kernel(), 799 va + UBC_UMAP_ADDR(umap), NULL)); 800 } 801 LIST_REMOVE(umap, list); 802 LIST_REMOVE(umap, hash); 803 umap->flags &= ~UMAP_MAPPING_CACHED; 804 umap->uobj = NULL; 805 } 806 mutex_exit(ubc_object.uobj.vmobjlock); 807 } 808