1 /* $NetBSD: uvm_bio.c,v 1.83 2015/05/27 19:43:40 rmind 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 1.83 2015/05/27 19:43:40 rmind 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 TAILQ_HEAD(ubc_inactive_head, ubc_map); 97 static struct ubc_object { 98 struct uvm_object uobj; /* glue for uvm_map() */ 99 char *kva; /* where ubc_object is mapped */ 100 struct ubc_map *umap; /* array of ubc_map's */ 101 102 LIST_HEAD(, ubc_map) *hash; /* hashtable for cached ubc_map's */ 103 u_long hashmask; /* mask for hashtable */ 104 105 struct ubc_inactive_head *inactive; 106 /* inactive queues for ubc_map's */ 107 } ubc_object; 108 109 const struct uvm_pagerops ubc_pager = { 110 .pgo_fault = ubc_fault, 111 /* ... rest are NULL */ 112 }; 113 114 int ubc_nwins = UBC_NWINS; 115 int ubc_winshift = UBC_WINSHIFT; 116 int ubc_winsize; 117 #if defined(PMAP_PREFER) 118 int ubc_nqueues; 119 #define UBC_NQUEUES ubc_nqueues 120 #else 121 #define UBC_NQUEUES 1 122 #endif 123 124 #if defined(UBC_STATS) 125 126 #define UBC_EVCNT_DEFINE(name) \ 127 struct evcnt ubc_evcnt_##name = \ 128 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "ubc", #name); \ 129 EVCNT_ATTACH_STATIC(ubc_evcnt_##name); 130 #define UBC_EVCNT_INCR(name) ubc_evcnt_##name.ev_count++ 131 132 #else /* defined(UBC_STATS) */ 133 134 #define UBC_EVCNT_DEFINE(name) /* nothing */ 135 #define UBC_EVCNT_INCR(name) /* nothing */ 136 137 #endif /* defined(UBC_STATS) */ 138 139 UBC_EVCNT_DEFINE(wincachehit) 140 UBC_EVCNT_DEFINE(wincachemiss) 141 UBC_EVCNT_DEFINE(faultbusy) 142 143 /* 144 * ubc_init 145 * 146 * init pager private data structures. 147 */ 148 149 void 150 ubc_init(void) 151 { 152 struct ubc_map *umap; 153 vaddr_t va; 154 int i; 155 156 /* 157 * Make sure ubc_winshift is sane. 158 */ 159 if (ubc_winshift < PAGE_SHIFT) 160 ubc_winshift = PAGE_SHIFT; 161 162 /* 163 * init ubc_object. 164 * alloc and init ubc_map's. 165 * init inactive queues. 166 * alloc and init hashtable. 167 * map in ubc_object. 168 */ 169 170 uvm_obj_init(&ubc_object.uobj, &ubc_pager, true, UVM_OBJ_KERN); 171 172 ubc_object.umap = kmem_zalloc(ubc_nwins * sizeof(struct ubc_map), 173 KM_SLEEP); 174 if (ubc_object.umap == NULL) 175 panic("ubc_init: failed to allocate ubc_map"); 176 177 if (ubc_winshift < PAGE_SHIFT) { 178 ubc_winshift = PAGE_SHIFT; 179 } 180 va = (vaddr_t)1L; 181 #ifdef PMAP_PREFER 182 PMAP_PREFER(0, &va, 0, 0); /* kernel is never topdown */ 183 ubc_nqueues = va >> ubc_winshift; 184 if (ubc_nqueues == 0) { 185 ubc_nqueues = 1; 186 } 187 #endif 188 ubc_winsize = 1 << ubc_winshift; 189 ubc_object.inactive = kmem_alloc(UBC_NQUEUES * 190 sizeof(struct ubc_inactive_head), KM_SLEEP); 191 if (ubc_object.inactive == NULL) 192 panic("ubc_init: failed to allocate inactive queue heads"); 193 for (i = 0; i < UBC_NQUEUES; i++) { 194 TAILQ_INIT(&ubc_object.inactive[i]); 195 } 196 for (i = 0; i < ubc_nwins; i++) { 197 umap = &ubc_object.umap[i]; 198 TAILQ_INSERT_TAIL(&ubc_object.inactive[i & (UBC_NQUEUES - 1)], 199 umap, inactive); 200 } 201 202 ubc_object.hash = hashinit(ubc_nwins, HASH_LIST, true, 203 &ubc_object.hashmask); 204 for (i = 0; i <= ubc_object.hashmask; i++) { 205 LIST_INIT(&ubc_object.hash[i]); 206 } 207 208 if (uvm_map(kernel_map, (vaddr_t *)&ubc_object.kva, 209 ubc_nwins << ubc_winshift, &ubc_object.uobj, 0, (vsize_t)va, 210 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE, 211 UVM_ADV_RANDOM, UVM_FLAG_NOMERGE)) != 0) { 212 panic("ubc_init: failed to map ubc_object"); 213 } 214 } 215 216 void 217 ubchist_init(void) 218 { 219 220 UVMHIST_INIT(ubchist, 300); 221 } 222 223 /* 224 * ubc_fault_page: helper of ubc_fault to handle a single page. 225 * 226 * => Caller has UVM object locked. 227 * => Caller will perform pmap_update(). 228 */ 229 230 static inline int 231 ubc_fault_page(const struct uvm_faultinfo *ufi, const struct ubc_map *umap, 232 struct vm_page *pg, vm_prot_t prot, vm_prot_t access_type, vaddr_t va) 233 { 234 struct uvm_object *uobj; 235 vm_prot_t mask; 236 int error; 237 bool rdonly; 238 239 uobj = pg->uobject; 240 KASSERT(mutex_owned(uobj->vmobjlock)); 241 242 if (pg->flags & PG_WANTED) { 243 wakeup(pg); 244 } 245 KASSERT((pg->flags & PG_FAKE) == 0); 246 if (pg->flags & PG_RELEASED) { 247 mutex_enter(&uvm_pageqlock); 248 uvm_pagefree(pg); 249 mutex_exit(&uvm_pageqlock); 250 return 0; 251 } 252 if (pg->loan_count != 0) { 253 254 /* 255 * Avoid unneeded loan break, if possible. 256 */ 257 258 if ((access_type & VM_PROT_WRITE) == 0) { 259 prot &= ~VM_PROT_WRITE; 260 } 261 if (prot & VM_PROT_WRITE) { 262 struct vm_page *newpg; 263 264 newpg = uvm_loanbreak(pg); 265 if (newpg == NULL) { 266 uvm_page_unbusy(&pg, 1); 267 return ENOMEM; 268 } 269 pg = newpg; 270 } 271 } 272 273 /* 274 * Note that a page whose backing store is partially allocated 275 * is marked as PG_RDONLY. 276 */ 277 278 KASSERT((pg->flags & PG_RDONLY) == 0 || 279 (access_type & VM_PROT_WRITE) == 0 || 280 pg->offset < umap->writeoff || 281 pg->offset + PAGE_SIZE > umap->writeoff + umap->writelen); 282 283 rdonly = ((access_type & VM_PROT_WRITE) == 0 && 284 (pg->flags & PG_RDONLY) != 0) || 285 UVM_OBJ_NEEDS_WRITEFAULT(uobj); 286 mask = rdonly ? ~VM_PROT_WRITE : VM_PROT_ALL; 287 288 error = pmap_enter(ufi->orig_map->pmap, va, VM_PAGE_TO_PHYS(pg), 289 prot & mask, PMAP_CANFAIL | (access_type & mask)); 290 291 mutex_enter(&uvm_pageqlock); 292 uvm_pageactivate(pg); 293 mutex_exit(&uvm_pageqlock); 294 pg->flags &= ~(PG_BUSY|PG_WANTED); 295 UVM_PAGE_OWN(pg, NULL); 296 297 return error; 298 } 299 300 /* 301 * ubc_fault: fault routine for ubc mapping 302 */ 303 304 static int 305 ubc_fault(struct uvm_faultinfo *ufi, vaddr_t ign1, struct vm_page **ign2, 306 int ign3, int ign4, vm_prot_t access_type, int flags) 307 { 308 struct uvm_object *uobj; 309 struct ubc_map *umap; 310 vaddr_t va, eva, ubc_offset, slot_offset; 311 struct vm_page *pgs[ubc_winsize >> PAGE_SHIFT]; 312 int i, error, npages; 313 vm_prot_t prot; 314 315 UVMHIST_FUNC("ubc_fault"); UVMHIST_CALLED(ubchist); 316 317 /* 318 * no need to try with PGO_LOCKED... 319 * we don't need to have the map locked since we know that 320 * no one will mess with it until our reference is released. 321 */ 322 323 if (flags & PGO_LOCKED) { 324 uvmfault_unlockall(ufi, NULL, &ubc_object.uobj); 325 flags &= ~PGO_LOCKED; 326 } 327 328 va = ufi->orig_rvaddr; 329 ubc_offset = va - (vaddr_t)ubc_object.kva; 330 umap = &ubc_object.umap[ubc_offset >> ubc_winshift]; 331 KASSERT(umap->refcount != 0); 332 KASSERT((umap->flags & UMAP_PAGES_LOCKED) == 0); 333 slot_offset = ubc_offset & (ubc_winsize - 1); 334 335 /* 336 * some platforms cannot write to individual bytes atomically, so 337 * software has to do read/modify/write of larger quantities instead. 338 * this means that the access_type for "write" operations 339 * can be VM_PROT_READ, which confuses us mightily. 340 * 341 * deal with this by resetting access_type based on the info 342 * that ubc_alloc() stores for us. 343 */ 344 345 access_type = umap->writelen ? VM_PROT_WRITE : VM_PROT_READ; 346 UVMHIST_LOG(ubchist, "va 0x%lx ubc_offset 0x%lx access_type %d", 347 va, ubc_offset, access_type, 0); 348 349 #ifdef DIAGNOSTIC 350 if ((access_type & VM_PROT_WRITE) != 0) { 351 if (slot_offset < trunc_page(umap->writeoff) || 352 umap->writeoff + umap->writelen <= slot_offset) { 353 panic("ubc_fault: out of range write"); 354 } 355 } 356 #endif 357 358 /* no umap locking needed since we have a ref on the umap */ 359 uobj = umap->uobj; 360 361 if ((access_type & VM_PROT_WRITE) == 0) { 362 npages = (ubc_winsize - slot_offset) >> PAGE_SHIFT; 363 } else { 364 npages = (round_page(umap->offset + umap->writeoff + 365 umap->writelen) - (umap->offset + slot_offset)) 366 >> PAGE_SHIFT; 367 flags |= PGO_PASTEOF; 368 } 369 370 again: 371 memset(pgs, 0, sizeof (pgs)); 372 mutex_enter(uobj->vmobjlock); 373 374 UVMHIST_LOG(ubchist, "slot_offset 0x%x writeoff 0x%x writelen 0x%x ", 375 slot_offset, umap->writeoff, umap->writelen, 0); 376 UVMHIST_LOG(ubchist, "getpages uobj %p offset 0x%x npages %d", 377 uobj, umap->offset + slot_offset, npages, 0); 378 379 error = (*uobj->pgops->pgo_get)(uobj, umap->offset + slot_offset, pgs, 380 &npages, 0, access_type, umap->advice, flags | PGO_NOBLOCKALLOC | 381 PGO_NOTIMESTAMP); 382 UVMHIST_LOG(ubchist, "getpages error %d npages %d", error, npages, 0, 383 0); 384 385 if (error == EAGAIN) { 386 kpause("ubc_fault", false, hz >> 2, NULL); 387 goto again; 388 } 389 if (error) { 390 return error; 391 } 392 393 /* 394 * For virtually-indexed, virtually-tagged caches we should avoid 395 * creating writable mappings when we do not absolutely need them, 396 * since the "compatible alias" trick does not work on such caches. 397 * Otherwise, we can always map the pages writable. 398 */ 399 400 #ifdef PMAP_CACHE_VIVT 401 prot = VM_PROT_READ | access_type; 402 #else 403 prot = VM_PROT_READ | VM_PROT_WRITE; 404 #endif 405 406 va = ufi->orig_rvaddr; 407 eva = ufi->orig_rvaddr + (npages << PAGE_SHIFT); 408 409 UVMHIST_LOG(ubchist, "va 0x%lx eva 0x%lx", va, eva, 0, 0); 410 411 /* 412 * Note: normally all returned pages would have the same UVM object. 413 * However, layered file-systems and e.g. tmpfs, may return pages 414 * which belong to underlying UVM object. In such case, lock is 415 * shared amongst the objects. 416 */ 417 mutex_enter(uobj->vmobjlock); 418 for (i = 0; va < eva; i++, va += PAGE_SIZE) { 419 struct vm_page *pg; 420 421 UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i], 0, 0); 422 pg = pgs[i]; 423 424 if (pg == NULL || pg == PGO_DONTCARE) { 425 continue; 426 } 427 KASSERT(uobj->vmobjlock == pg->uobject->vmobjlock); 428 error = ubc_fault_page(ufi, umap, pg, prot, access_type, va); 429 if (error) { 430 /* 431 * Flush (there might be pages entered), drop the lock, 432 * and perform uvm_wait(). Note: page will re-fault. 433 */ 434 pmap_update(ufi->orig_map->pmap); 435 mutex_exit(uobj->vmobjlock); 436 uvm_wait("ubc_fault"); 437 mutex_enter(uobj->vmobjlock); 438 } 439 } 440 /* Must make VA visible before the unlock. */ 441 pmap_update(ufi->orig_map->pmap); 442 mutex_exit(uobj->vmobjlock); 443 444 return 0; 445 } 446 447 /* 448 * local functions 449 */ 450 451 static struct ubc_map * 452 ubc_find_mapping(struct uvm_object *uobj, voff_t offset) 453 { 454 struct ubc_map *umap; 455 456 LIST_FOREACH(umap, &ubc_object.hash[UBC_HASH(uobj, offset)], hash) { 457 if (umap->uobj == uobj && umap->offset == offset) { 458 return umap; 459 } 460 } 461 return NULL; 462 } 463 464 465 /* 466 * ubc interface functions 467 */ 468 469 /* 470 * ubc_alloc: allocate a file mapping window 471 */ 472 473 void * 474 ubc_alloc(struct uvm_object *uobj, voff_t offset, vsize_t *lenp, int advice, 475 int flags) 476 { 477 vaddr_t slot_offset, va; 478 struct ubc_map *umap; 479 voff_t umap_offset; 480 int error; 481 UVMHIST_FUNC("ubc_alloc"); UVMHIST_CALLED(ubchist); 482 483 UVMHIST_LOG(ubchist, "uobj %p offset 0x%lx len 0x%lx", 484 uobj, offset, *lenp, 0); 485 486 KASSERT(*lenp > 0); 487 umap_offset = (offset & ~((voff_t)ubc_winsize - 1)); 488 slot_offset = (vaddr_t)(offset & ((voff_t)ubc_winsize - 1)); 489 *lenp = MIN(*lenp, ubc_winsize - slot_offset); 490 491 mutex_enter(ubc_object.uobj.vmobjlock); 492 again: 493 /* 494 * The UVM object is already referenced. 495 * Lock order: UBC object -> ubc_map::uobj. 496 */ 497 umap = ubc_find_mapping(uobj, umap_offset); 498 if (umap == NULL) { 499 struct uvm_object *oobj; 500 501 UBC_EVCNT_INCR(wincachemiss); 502 umap = TAILQ_FIRST(UBC_QUEUE(offset)); 503 if (umap == NULL) { 504 kpause("ubc_alloc", false, hz >> 2, 505 ubc_object.uobj.vmobjlock); 506 goto again; 507 } 508 509 va = UBC_UMAP_ADDR(umap); 510 oobj = umap->uobj; 511 512 /* 513 * Remove from old hash (if any), add to new hash. 514 */ 515 516 if (oobj != NULL) { 517 /* 518 * Mapping must be removed before the list entry, 519 * since there is a race with ubc_purge(). 520 */ 521 if (umap->flags & UMAP_MAPPING_CACHED) { 522 umap->flags &= ~UMAP_MAPPING_CACHED; 523 mutex_enter(oobj->vmobjlock); 524 pmap_remove(pmap_kernel(), va, 525 va + ubc_winsize); 526 pmap_update(pmap_kernel()); 527 mutex_exit(oobj->vmobjlock); 528 } 529 LIST_REMOVE(umap, hash); 530 LIST_REMOVE(umap, list); 531 } else { 532 KASSERT((umap->flags & UMAP_MAPPING_CACHED) == 0); 533 } 534 umap->uobj = uobj; 535 umap->offset = umap_offset; 536 LIST_INSERT_HEAD(&ubc_object.hash[UBC_HASH(uobj, umap_offset)], 537 umap, hash); 538 LIST_INSERT_HEAD(&uobj->uo_ubc, umap, list); 539 } else { 540 UBC_EVCNT_INCR(wincachehit); 541 va = UBC_UMAP_ADDR(umap); 542 } 543 544 if (umap->refcount == 0) { 545 TAILQ_REMOVE(UBC_QUEUE(offset), umap, inactive); 546 } 547 548 if (flags & UBC_WRITE) { 549 KASSERTMSG(umap->writeoff == 0 && umap->writelen == 0, 550 "ubc_alloc: concurrent writes to uobj %p", uobj); 551 umap->writeoff = slot_offset; 552 umap->writelen = *lenp; 553 } 554 555 umap->refcount++; 556 umap->advice = advice; 557 mutex_exit(ubc_object.uobj.vmobjlock); 558 UVMHIST_LOG(ubchist, "umap %p refs %d va %p flags 0x%x", 559 umap, umap->refcount, va, flags); 560 561 if (flags & UBC_FAULTBUSY) { 562 int npages = (*lenp + PAGE_SIZE - 1) >> PAGE_SHIFT; 563 struct vm_page *pgs[npages]; 564 int gpflags = 565 PGO_SYNCIO|PGO_OVERWRITE|PGO_PASTEOF|PGO_NOBLOCKALLOC| 566 PGO_NOTIMESTAMP; 567 int i; 568 KDASSERT(flags & UBC_WRITE); 569 KASSERT(umap->refcount == 1); 570 571 UBC_EVCNT_INCR(faultbusy); 572 again_faultbusy: 573 mutex_enter(uobj->vmobjlock); 574 if (umap->flags & UMAP_MAPPING_CACHED) { 575 umap->flags &= ~UMAP_MAPPING_CACHED; 576 pmap_remove(pmap_kernel(), va, va + ubc_winsize); 577 } 578 memset(pgs, 0, sizeof(pgs)); 579 580 error = (*uobj->pgops->pgo_get)(uobj, trunc_page(offset), pgs, 581 &npages, 0, VM_PROT_READ | VM_PROT_WRITE, advice, gpflags); 582 UVMHIST_LOG(ubchist, "faultbusy getpages %d", error, 0, 0, 0); 583 if (error) { 584 /* 585 * Flush: the mapping above might have been removed. 586 */ 587 pmap_update(pmap_kernel()); 588 goto out; 589 } 590 for (i = 0; i < npages; i++) { 591 struct vm_page *pg = pgs[i]; 592 593 KASSERT(pg->uobject == uobj); 594 if (pg->loan_count != 0) { 595 mutex_enter(uobj->vmobjlock); 596 if (pg->loan_count != 0) { 597 pg = uvm_loanbreak(pg); 598 } 599 if (pg == NULL) { 600 pmap_kremove(va, ubc_winsize); 601 pmap_update(pmap_kernel()); 602 uvm_page_unbusy(pgs, npages); 603 mutex_exit(uobj->vmobjlock); 604 uvm_wait("ubc_alloc"); 605 goto again_faultbusy; 606 } 607 mutex_exit(uobj->vmobjlock); 608 pgs[i] = pg; 609 } 610 pmap_kenter_pa(va + slot_offset + (i << PAGE_SHIFT), 611 VM_PAGE_TO_PHYS(pg), 612 VM_PROT_READ | VM_PROT_WRITE, 0); 613 } 614 pmap_update(pmap_kernel()); 615 umap->flags |= UMAP_PAGES_LOCKED; 616 } else { 617 KASSERT((umap->flags & UMAP_PAGES_LOCKED) == 0); 618 } 619 620 out: 621 return (void *)(va + slot_offset); 622 } 623 624 /* 625 * ubc_release: free a file mapping window. 626 */ 627 628 void 629 ubc_release(void *va, int flags) 630 { 631 struct ubc_map *umap; 632 struct uvm_object *uobj; 633 vaddr_t umapva; 634 bool unmapped; 635 UVMHIST_FUNC("ubc_release"); UVMHIST_CALLED(ubchist); 636 637 UVMHIST_LOG(ubchist, "va %p", va, 0, 0, 0); 638 umap = &ubc_object.umap[((char *)va - ubc_object.kva) >> ubc_winshift]; 639 umapva = UBC_UMAP_ADDR(umap); 640 uobj = umap->uobj; 641 KASSERT(uobj != NULL); 642 643 if (umap->flags & UMAP_PAGES_LOCKED) { 644 const voff_t slot_offset = umap->writeoff; 645 const voff_t endoff = umap->writeoff + umap->writelen; 646 const voff_t zerolen = round_page(endoff) - endoff; 647 const u_int npages = (round_page(endoff) - 648 trunc_page(slot_offset)) >> PAGE_SHIFT; 649 struct vm_page *pgs[npages]; 650 651 KASSERT((umap->flags & UMAP_MAPPING_CACHED) == 0); 652 if (zerolen) { 653 memset((char *)umapva + endoff, 0, zerolen); 654 } 655 umap->flags &= ~UMAP_PAGES_LOCKED; 656 mutex_enter(uobj->vmobjlock); 657 mutex_enter(&uvm_pageqlock); 658 for (u_int i = 0; i < npages; i++) { 659 paddr_t pa; 660 bool rv __diagused; 661 662 rv = pmap_extract(pmap_kernel(), 663 umapva + slot_offset + (i << PAGE_SHIFT), &pa); 664 KASSERT(rv); 665 pgs[i] = PHYS_TO_VM_PAGE(pa); 666 pgs[i]->flags &= ~(PG_FAKE|PG_CLEAN); 667 KASSERT(pgs[i]->loan_count == 0); 668 uvm_pageactivate(pgs[i]); 669 } 670 mutex_exit(&uvm_pageqlock); 671 pmap_kremove(umapva, ubc_winsize); 672 pmap_update(pmap_kernel()); 673 uvm_page_unbusy(pgs, npages); 674 mutex_exit(uobj->vmobjlock); 675 unmapped = true; 676 } else { 677 unmapped = false; 678 } 679 680 mutex_enter(ubc_object.uobj.vmobjlock); 681 umap->writeoff = 0; 682 umap->writelen = 0; 683 umap->refcount--; 684 if (umap->refcount == 0) { 685 if (flags & UBC_UNMAP) { 686 /* 687 * Invalidate any cached mappings if requested. 688 * This is typically used to avoid leaving 689 * incompatible cache aliases around indefinitely. 690 */ 691 mutex_enter(uobj->vmobjlock); 692 pmap_remove(pmap_kernel(), umapva, 693 umapva + ubc_winsize); 694 pmap_update(pmap_kernel()); 695 mutex_exit(uobj->vmobjlock); 696 697 umap->flags &= ~UMAP_MAPPING_CACHED; 698 LIST_REMOVE(umap, hash); 699 LIST_REMOVE(umap, list); 700 umap->uobj = NULL; 701 TAILQ_INSERT_HEAD(UBC_QUEUE(umap->offset), umap, 702 inactive); 703 } else { 704 if (!unmapped) { 705 umap->flags |= UMAP_MAPPING_CACHED; 706 } 707 TAILQ_INSERT_TAIL(UBC_QUEUE(umap->offset), umap, 708 inactive); 709 } 710 } 711 UVMHIST_LOG(ubchist, "umap %p refs %d", umap, umap->refcount, 0, 0); 712 mutex_exit(ubc_object.uobj.vmobjlock); 713 } 714 715 /* 716 * ubc_uiomove: move data to/from an object. 717 */ 718 719 int 720 ubc_uiomove(struct uvm_object *uobj, struct uio *uio, vsize_t todo, int advice, 721 int flags) 722 { 723 const bool overwrite = (flags & UBC_FAULTBUSY) != 0; 724 voff_t off; 725 int error; 726 727 KASSERT(todo <= uio->uio_resid); 728 KASSERT(((flags & UBC_WRITE) != 0 && uio->uio_rw == UIO_WRITE) || 729 ((flags & UBC_READ) != 0 && uio->uio_rw == UIO_READ)); 730 731 off = uio->uio_offset; 732 error = 0; 733 while (todo > 0) { 734 vsize_t bytelen = todo; 735 void *win; 736 737 win = ubc_alloc(uobj, off, &bytelen, advice, flags); 738 if (error == 0) { 739 error = uiomove(win, bytelen, uio); 740 } 741 if (error != 0 && overwrite) { 742 /* 743 * if we haven't initialized the pages yet, 744 * do it now. it's safe to use memset here 745 * because we just mapped the pages above. 746 */ 747 printf("%s: error=%d\n", __func__, error); 748 memset(win, 0, bytelen); 749 } 750 ubc_release(win, flags); 751 off += bytelen; 752 todo -= bytelen; 753 if (error != 0 && (flags & UBC_PARTIALOK) != 0) { 754 break; 755 } 756 } 757 758 return error; 759 } 760 761 /* 762 * ubc_zerorange: set a range of bytes in an object to zero. 763 */ 764 765 void 766 ubc_zerorange(struct uvm_object *uobj, off_t off, size_t len, int flags) 767 { 768 void *win; 769 770 /* 771 * XXXUBC invent kzero() and use it 772 */ 773 774 while (len) { 775 vsize_t bytelen = len; 776 777 win = ubc_alloc(uobj, off, &bytelen, UVM_ADV_NORMAL, UBC_WRITE); 778 memset(win, 0, bytelen); 779 ubc_release(win, flags); 780 781 off += bytelen; 782 len -= bytelen; 783 } 784 } 785 786 /* 787 * ubc_purge: disassociate ubc_map structures from an empty uvm_object. 788 */ 789 790 void 791 ubc_purge(struct uvm_object *uobj) 792 { 793 struct ubc_map *umap; 794 vaddr_t va; 795 796 KASSERT(uobj->uo_npages == 0); 797 798 /* 799 * Safe to check without lock held, as ubc_alloc() removes 800 * the mapping and list entry in the correct order. 801 */ 802 if (__predict_true(LIST_EMPTY(&uobj->uo_ubc))) { 803 return; 804 } 805 mutex_enter(ubc_object.uobj.vmobjlock); 806 while ((umap = LIST_FIRST(&uobj->uo_ubc)) != NULL) { 807 KASSERT(umap->refcount == 0); 808 for (va = 0; va < ubc_winsize; va += PAGE_SIZE) { 809 KASSERT(!pmap_extract(pmap_kernel(), 810 va + UBC_UMAP_ADDR(umap), NULL)); 811 } 812 LIST_REMOVE(umap, list); 813 LIST_REMOVE(umap, hash); 814 umap->flags &= ~UMAP_MAPPING_CACHED; 815 umap->uobj = NULL; 816 } 817 mutex_exit(ubc_object.uobj.vmobjlock); 818 } 819