1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)vm_map.c 8.3 (Berkeley) 1/12/94 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 39 * 40 * Permission to use, copy, modify and distribute this software and 41 * its documentation is hereby granted, provided that both the copyright 42 * notice and this permission notice appear in all copies of the 43 * software, derivative works or modified versions, and any portions 44 * thereof, and that both notices appear in supporting documentation. 45 * 46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 49 * 50 * Carnegie Mellon requests users of this software to return to 51 * 52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 53 * School of Computer Science 54 * Carnegie Mellon University 55 * Pittsburgh PA 15213-3890 56 * 57 * any improvements or extensions that they make and grant Carnegie the 58 * rights to redistribute these changes. 59 */ 60 61 /* 62 * Virtual memory mapping module. 63 */ 64 65 #include <sys/cdefs.h> 66 __FBSDID("$FreeBSD$"); 67 68 #include <sys/param.h> 69 #include <sys/systm.h> 70 #include <sys/kernel.h> 71 #include <sys/ktr.h> 72 #include <sys/lock.h> 73 #include <sys/mutex.h> 74 #include <sys/proc.h> 75 #include <sys/vmmeter.h> 76 #include <sys/mman.h> 77 #include <sys/vnode.h> 78 #include <sys/racct.h> 79 #include <sys/resourcevar.h> 80 #include <sys/rwlock.h> 81 #include <sys/file.h> 82 #include <sys/sysctl.h> 83 #include <sys/sysent.h> 84 #include <sys/shm.h> 85 86 #include <vm/vm.h> 87 #include <vm/vm_param.h> 88 #include <vm/pmap.h> 89 #include <vm/vm_map.h> 90 #include <vm/vm_page.h> 91 #include <vm/vm_object.h> 92 #include <vm/vm_pager.h> 93 #include <vm/vm_kern.h> 94 #include <vm/vm_extern.h> 95 #include <vm/vnode_pager.h> 96 #include <vm/swap_pager.h> 97 #include <vm/uma.h> 98 99 /* 100 * Virtual memory maps provide for the mapping, protection, 101 * and sharing of virtual memory objects. In addition, 102 * this module provides for an efficient virtual copy of 103 * memory from one map to another. 104 * 105 * Synchronization is required prior to most operations. 106 * 107 * Maps consist of an ordered doubly-linked list of simple 108 * entries; a self-adjusting binary search tree of these 109 * entries is used to speed up lookups. 110 * 111 * Since portions of maps are specified by start/end addresses, 112 * which may not align with existing map entries, all 113 * routines merely "clip" entries to these start/end values. 114 * [That is, an entry is split into two, bordering at a 115 * start or end value.] Note that these clippings may not 116 * always be necessary (as the two resulting entries are then 117 * not changed); however, the clipping is done for convenience. 118 * 119 * As mentioned above, virtual copy operations are performed 120 * by copying VM object references from one map to 121 * another, and then marking both regions as copy-on-write. 122 */ 123 124 static struct mtx map_sleep_mtx; 125 static uma_zone_t mapentzone; 126 static uma_zone_t kmapentzone; 127 static uma_zone_t mapzone; 128 static uma_zone_t vmspace_zone; 129 static int vmspace_zinit(void *mem, int size, int flags); 130 static int vm_map_zinit(void *mem, int ize, int flags); 131 static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, 132 vm_offset_t max); 133 static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map); 134 static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry); 135 static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry); 136 #ifdef INVARIANTS 137 static void vm_map_zdtor(void *mem, int size, void *arg); 138 static void vmspace_zdtor(void *mem, int size, void *arg); 139 #endif 140 static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, 141 vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max, 142 int cow); 143 static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, 144 vm_offset_t failed_addr); 145 146 #define ENTRY_CHARGED(e) ((e)->cred != NULL || \ 147 ((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \ 148 !((e)->eflags & MAP_ENTRY_NEEDS_COPY))) 149 150 /* 151 * PROC_VMSPACE_{UN,}LOCK() can be a noop as long as vmspaces are type 152 * stable. 153 */ 154 #define PROC_VMSPACE_LOCK(p) do { } while (0) 155 #define PROC_VMSPACE_UNLOCK(p) do { } while (0) 156 157 /* 158 * VM_MAP_RANGE_CHECK: [ internal use only ] 159 * 160 * Asserts that the starting and ending region 161 * addresses fall within the valid range of the map. 162 */ 163 #define VM_MAP_RANGE_CHECK(map, start, end) \ 164 { \ 165 if (start < vm_map_min(map)) \ 166 start = vm_map_min(map); \ 167 if (end > vm_map_max(map)) \ 168 end = vm_map_max(map); \ 169 if (start > end) \ 170 start = end; \ 171 } 172 173 /* 174 * vm_map_startup: 175 * 176 * Initialize the vm_map module. Must be called before 177 * any other vm_map routines. 178 * 179 * Map and entry structures are allocated from the general 180 * purpose memory pool with some exceptions: 181 * 182 * - The kernel map and kmem submap are allocated statically. 183 * - Kernel map entries are allocated out of a static pool. 184 * 185 * These restrictions are necessary since malloc() uses the 186 * maps and requires map entries. 187 */ 188 189 void 190 vm_map_startup(void) 191 { 192 mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF); 193 mapzone = uma_zcreate("MAP", sizeof(struct vm_map), NULL, 194 #ifdef INVARIANTS 195 vm_map_zdtor, 196 #else 197 NULL, 198 #endif 199 vm_map_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 200 uma_prealloc(mapzone, MAX_KMAP); 201 kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry), 202 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 203 UMA_ZONE_MTXCLASS | UMA_ZONE_VM); 204 mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry), 205 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 206 vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL, 207 #ifdef INVARIANTS 208 vmspace_zdtor, 209 #else 210 NULL, 211 #endif 212 vmspace_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 213 } 214 215 static int 216 vmspace_zinit(void *mem, int size, int flags) 217 { 218 struct vmspace *vm; 219 220 vm = (struct vmspace *)mem; 221 222 vm->vm_map.pmap = NULL; 223 (void)vm_map_zinit(&vm->vm_map, sizeof(vm->vm_map), flags); 224 PMAP_LOCK_INIT(vmspace_pmap(vm)); 225 return (0); 226 } 227 228 static int 229 vm_map_zinit(void *mem, int size, int flags) 230 { 231 vm_map_t map; 232 233 map = (vm_map_t)mem; 234 memset(map, 0, sizeof(*map)); 235 mtx_init(&map->system_mtx, "vm map (system)", NULL, MTX_DEF | MTX_DUPOK); 236 sx_init(&map->lock, "vm map (user)"); 237 return (0); 238 } 239 240 #ifdef INVARIANTS 241 static void 242 vmspace_zdtor(void *mem, int size, void *arg) 243 { 244 struct vmspace *vm; 245 246 vm = (struct vmspace *)mem; 247 248 vm_map_zdtor(&vm->vm_map, sizeof(vm->vm_map), arg); 249 } 250 static void 251 vm_map_zdtor(void *mem, int size, void *arg) 252 { 253 vm_map_t map; 254 255 map = (vm_map_t)mem; 256 KASSERT(map->nentries == 0, 257 ("map %p nentries == %d on free.", 258 map, map->nentries)); 259 KASSERT(map->size == 0, 260 ("map %p size == %lu on free.", 261 map, (unsigned long)map->size)); 262 } 263 #endif /* INVARIANTS */ 264 265 /* 266 * Allocate a vmspace structure, including a vm_map and pmap, 267 * and initialize those structures. The refcnt is set to 1. 268 * 269 * If 'pinit' is NULL then the embedded pmap is initialized via pmap_pinit(). 270 */ 271 struct vmspace * 272 vmspace_alloc(vm_offset_t min, vm_offset_t max, pmap_pinit_t pinit) 273 { 274 struct vmspace *vm; 275 276 vm = uma_zalloc(vmspace_zone, M_WAITOK); 277 278 KASSERT(vm->vm_map.pmap == NULL, ("vm_map.pmap must be NULL")); 279 280 if (pinit == NULL) 281 pinit = &pmap_pinit; 282 283 if (!pinit(vmspace_pmap(vm))) { 284 uma_zfree(vmspace_zone, vm); 285 return (NULL); 286 } 287 CTR1(KTR_VM, "vmspace_alloc: %p", vm); 288 _vm_map_init(&vm->vm_map, vmspace_pmap(vm), min, max); 289 vm->vm_refcnt = 1; 290 vm->vm_shm = NULL; 291 vm->vm_swrss = 0; 292 vm->vm_tsize = 0; 293 vm->vm_dsize = 0; 294 vm->vm_ssize = 0; 295 vm->vm_taddr = 0; 296 vm->vm_daddr = 0; 297 vm->vm_maxsaddr = 0; 298 return (vm); 299 } 300 301 static void 302 vmspace_container_reset(struct proc *p) 303 { 304 305 #ifdef RACCT 306 PROC_LOCK(p); 307 racct_set(p, RACCT_DATA, 0); 308 racct_set(p, RACCT_STACK, 0); 309 racct_set(p, RACCT_RSS, 0); 310 racct_set(p, RACCT_MEMLOCK, 0); 311 racct_set(p, RACCT_VMEM, 0); 312 PROC_UNLOCK(p); 313 #endif 314 } 315 316 static inline void 317 vmspace_dofree(struct vmspace *vm) 318 { 319 320 CTR1(KTR_VM, "vmspace_free: %p", vm); 321 322 /* 323 * Make sure any SysV shm is freed, it might not have been in 324 * exit1(). 325 */ 326 shmexit(vm); 327 328 /* 329 * Lock the map, to wait out all other references to it. 330 * Delete all of the mappings and pages they hold, then call 331 * the pmap module to reclaim anything left. 332 */ 333 (void)vm_map_remove(&vm->vm_map, vm->vm_map.min_offset, 334 vm->vm_map.max_offset); 335 336 pmap_release(vmspace_pmap(vm)); 337 vm->vm_map.pmap = NULL; 338 uma_zfree(vmspace_zone, vm); 339 } 340 341 void 342 vmspace_free(struct vmspace *vm) 343 { 344 345 if (vm->vm_refcnt == 0) 346 panic("vmspace_free: attempt to free already freed vmspace"); 347 348 if (atomic_fetchadd_int(&vm->vm_refcnt, -1) == 1) 349 vmspace_dofree(vm); 350 } 351 352 void 353 vmspace_exitfree(struct proc *p) 354 { 355 struct vmspace *vm; 356 357 PROC_VMSPACE_LOCK(p); 358 vm = p->p_vmspace; 359 p->p_vmspace = NULL; 360 PROC_VMSPACE_UNLOCK(p); 361 KASSERT(vm == &vmspace0, ("vmspace_exitfree: wrong vmspace")); 362 vmspace_free(vm); 363 } 364 365 void 366 vmspace_exit(struct thread *td) 367 { 368 int refcnt; 369 struct vmspace *vm; 370 struct proc *p; 371 372 /* 373 * Release user portion of address space. 374 * This releases references to vnodes, 375 * which could cause I/O if the file has been unlinked. 376 * Need to do this early enough that we can still sleep. 377 * 378 * The last exiting process to reach this point releases as 379 * much of the environment as it can. vmspace_dofree() is the 380 * slower fallback in case another process had a temporary 381 * reference to the vmspace. 382 */ 383 384 p = td->td_proc; 385 vm = p->p_vmspace; 386 atomic_add_int(&vmspace0.vm_refcnt, 1); 387 do { 388 refcnt = vm->vm_refcnt; 389 if (refcnt > 1 && p->p_vmspace != &vmspace0) { 390 /* Switch now since other proc might free vmspace */ 391 PROC_VMSPACE_LOCK(p); 392 p->p_vmspace = &vmspace0; 393 PROC_VMSPACE_UNLOCK(p); 394 pmap_activate(td); 395 } 396 } while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); 397 if (refcnt == 1) { 398 if (p->p_vmspace != vm) { 399 /* vmspace not yet freed, switch back */ 400 PROC_VMSPACE_LOCK(p); 401 p->p_vmspace = vm; 402 PROC_VMSPACE_UNLOCK(p); 403 pmap_activate(td); 404 } 405 pmap_remove_pages(vmspace_pmap(vm)); 406 /* Switch now since this proc will free vmspace */ 407 PROC_VMSPACE_LOCK(p); 408 p->p_vmspace = &vmspace0; 409 PROC_VMSPACE_UNLOCK(p); 410 pmap_activate(td); 411 vmspace_dofree(vm); 412 } 413 vmspace_container_reset(p); 414 } 415 416 /* Acquire reference to vmspace owned by another process. */ 417 418 struct vmspace * 419 vmspace_acquire_ref(struct proc *p) 420 { 421 struct vmspace *vm; 422 int refcnt; 423 424 PROC_VMSPACE_LOCK(p); 425 vm = p->p_vmspace; 426 if (vm == NULL) { 427 PROC_VMSPACE_UNLOCK(p); 428 return (NULL); 429 } 430 do { 431 refcnt = vm->vm_refcnt; 432 if (refcnt <= 0) { /* Avoid 0->1 transition */ 433 PROC_VMSPACE_UNLOCK(p); 434 return (NULL); 435 } 436 } while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt + 1)); 437 if (vm != p->p_vmspace) { 438 PROC_VMSPACE_UNLOCK(p); 439 vmspace_free(vm); 440 return (NULL); 441 } 442 PROC_VMSPACE_UNLOCK(p); 443 return (vm); 444 } 445 446 void 447 _vm_map_lock(vm_map_t map, const char *file, int line) 448 { 449 450 if (map->system_map) 451 mtx_lock_flags_(&map->system_mtx, 0, file, line); 452 else 453 sx_xlock_(&map->lock, file, line); 454 map->timestamp++; 455 } 456 457 static void 458 vm_map_process_deferred(void) 459 { 460 struct thread *td; 461 vm_map_entry_t entry, next; 462 vm_object_t object; 463 464 td = curthread; 465 entry = td->td_map_def_user; 466 td->td_map_def_user = NULL; 467 while (entry != NULL) { 468 next = entry->next; 469 if ((entry->eflags & MAP_ENTRY_VN_WRITECNT) != 0) { 470 /* 471 * Decrement the object's writemappings and 472 * possibly the vnode's v_writecount. 473 */ 474 KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, 475 ("Submap with writecount")); 476 object = entry->object.vm_object; 477 KASSERT(object != NULL, ("No object for writecount")); 478 vnode_pager_release_writecount(object, entry->start, 479 entry->end); 480 } 481 vm_map_entry_deallocate(entry, FALSE); 482 entry = next; 483 } 484 } 485 486 void 487 _vm_map_unlock(vm_map_t map, const char *file, int line) 488 { 489 490 if (map->system_map) 491 mtx_unlock_flags_(&map->system_mtx, 0, file, line); 492 else { 493 sx_xunlock_(&map->lock, file, line); 494 vm_map_process_deferred(); 495 } 496 } 497 498 void 499 _vm_map_lock_read(vm_map_t map, const char *file, int line) 500 { 501 502 if (map->system_map) 503 mtx_lock_flags_(&map->system_mtx, 0, file, line); 504 else 505 sx_slock_(&map->lock, file, line); 506 } 507 508 void 509 _vm_map_unlock_read(vm_map_t map, const char *file, int line) 510 { 511 512 if (map->system_map) 513 mtx_unlock_flags_(&map->system_mtx, 0, file, line); 514 else { 515 sx_sunlock_(&map->lock, file, line); 516 vm_map_process_deferred(); 517 } 518 } 519 520 int 521 _vm_map_trylock(vm_map_t map, const char *file, int line) 522 { 523 int error; 524 525 error = map->system_map ? 526 !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : 527 !sx_try_xlock_(&map->lock, file, line); 528 if (error == 0) 529 map->timestamp++; 530 return (error == 0); 531 } 532 533 int 534 _vm_map_trylock_read(vm_map_t map, const char *file, int line) 535 { 536 int error; 537 538 error = map->system_map ? 539 !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : 540 !sx_try_slock_(&map->lock, file, line); 541 return (error == 0); 542 } 543 544 /* 545 * _vm_map_lock_upgrade: [ internal use only ] 546 * 547 * Tries to upgrade a read (shared) lock on the specified map to a write 548 * (exclusive) lock. Returns the value "0" if the upgrade succeeds and a 549 * non-zero value if the upgrade fails. If the upgrade fails, the map is 550 * returned without a read or write lock held. 551 * 552 * Requires that the map be read locked. 553 */ 554 int 555 _vm_map_lock_upgrade(vm_map_t map, const char *file, int line) 556 { 557 unsigned int last_timestamp; 558 559 if (map->system_map) { 560 mtx_assert_(&map->system_mtx, MA_OWNED, file, line); 561 } else { 562 if (!sx_try_upgrade_(&map->lock, file, line)) { 563 last_timestamp = map->timestamp; 564 sx_sunlock_(&map->lock, file, line); 565 vm_map_process_deferred(); 566 /* 567 * If the map's timestamp does not change while the 568 * map is unlocked, then the upgrade succeeds. 569 */ 570 sx_xlock_(&map->lock, file, line); 571 if (last_timestamp != map->timestamp) { 572 sx_xunlock_(&map->lock, file, line); 573 return (1); 574 } 575 } 576 } 577 map->timestamp++; 578 return (0); 579 } 580 581 void 582 _vm_map_lock_downgrade(vm_map_t map, const char *file, int line) 583 { 584 585 if (map->system_map) { 586 mtx_assert_(&map->system_mtx, MA_OWNED, file, line); 587 } else 588 sx_downgrade_(&map->lock, file, line); 589 } 590 591 /* 592 * vm_map_locked: 593 * 594 * Returns a non-zero value if the caller holds a write (exclusive) lock 595 * on the specified map and the value "0" otherwise. 596 */ 597 int 598 vm_map_locked(vm_map_t map) 599 { 600 601 if (map->system_map) 602 return (mtx_owned(&map->system_mtx)); 603 else 604 return (sx_xlocked(&map->lock)); 605 } 606 607 #ifdef INVARIANTS 608 static void 609 _vm_map_assert_locked(vm_map_t map, const char *file, int line) 610 { 611 612 if (map->system_map) 613 mtx_assert_(&map->system_mtx, MA_OWNED, file, line); 614 else 615 sx_assert_(&map->lock, SA_XLOCKED, file, line); 616 } 617 618 #define VM_MAP_ASSERT_LOCKED(map) \ 619 _vm_map_assert_locked(map, LOCK_FILE, LOCK_LINE) 620 #else 621 #define VM_MAP_ASSERT_LOCKED(map) 622 #endif 623 624 /* 625 * _vm_map_unlock_and_wait: 626 * 627 * Atomically releases the lock on the specified map and puts the calling 628 * thread to sleep. The calling thread will remain asleep until either 629 * vm_map_wakeup() is performed on the map or the specified timeout is 630 * exceeded. 631 * 632 * WARNING! This function does not perform deferred deallocations of 633 * objects and map entries. Therefore, the calling thread is expected to 634 * reacquire the map lock after reawakening and later perform an ordinary 635 * unlock operation, such as vm_map_unlock(), before completing its 636 * operation on the map. 637 */ 638 int 639 _vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line) 640 { 641 642 mtx_lock(&map_sleep_mtx); 643 if (map->system_map) 644 mtx_unlock_flags_(&map->system_mtx, 0, file, line); 645 else 646 sx_xunlock_(&map->lock, file, line); 647 return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", 648 timo)); 649 } 650 651 /* 652 * vm_map_wakeup: 653 * 654 * Awaken any threads that have slept on the map using 655 * vm_map_unlock_and_wait(). 656 */ 657 void 658 vm_map_wakeup(vm_map_t map) 659 { 660 661 /* 662 * Acquire and release map_sleep_mtx to prevent a wakeup() 663 * from being performed (and lost) between the map unlock 664 * and the msleep() in _vm_map_unlock_and_wait(). 665 */ 666 mtx_lock(&map_sleep_mtx); 667 mtx_unlock(&map_sleep_mtx); 668 wakeup(&map->root); 669 } 670 671 void 672 vm_map_busy(vm_map_t map) 673 { 674 675 VM_MAP_ASSERT_LOCKED(map); 676 map->busy++; 677 } 678 679 void 680 vm_map_unbusy(vm_map_t map) 681 { 682 683 VM_MAP_ASSERT_LOCKED(map); 684 KASSERT(map->busy, ("vm_map_unbusy: not busy")); 685 if (--map->busy == 0 && (map->flags & MAP_BUSY_WAKEUP)) { 686 vm_map_modflags(map, 0, MAP_BUSY_WAKEUP); 687 wakeup(&map->busy); 688 } 689 } 690 691 void 692 vm_map_wait_busy(vm_map_t map) 693 { 694 695 VM_MAP_ASSERT_LOCKED(map); 696 while (map->busy) { 697 vm_map_modflags(map, MAP_BUSY_WAKEUP, 0); 698 if (map->system_map) 699 msleep(&map->busy, &map->system_mtx, 0, "mbusy", 0); 700 else 701 sx_sleep(&map->busy, &map->lock, 0, "mbusy", 0); 702 } 703 map->timestamp++; 704 } 705 706 long 707 vmspace_resident_count(struct vmspace *vmspace) 708 { 709 return pmap_resident_count(vmspace_pmap(vmspace)); 710 } 711 712 /* 713 * vm_map_create: 714 * 715 * Creates and returns a new empty VM map with 716 * the given physical map structure, and having 717 * the given lower and upper address bounds. 718 */ 719 vm_map_t 720 vm_map_create(pmap_t pmap, vm_offset_t min, vm_offset_t max) 721 { 722 vm_map_t result; 723 724 result = uma_zalloc(mapzone, M_WAITOK); 725 CTR1(KTR_VM, "vm_map_create: %p", result); 726 _vm_map_init(result, pmap, min, max); 727 return (result); 728 } 729 730 /* 731 * Initialize an existing vm_map structure 732 * such as that in the vmspace structure. 733 */ 734 static void 735 _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) 736 { 737 738 map->header.next = map->header.prev = &map->header; 739 map->needs_wakeup = FALSE; 740 map->system_map = 0; 741 map->pmap = pmap; 742 map->min_offset = min; 743 map->max_offset = max; 744 map->flags = 0; 745 map->root = NULL; 746 map->timestamp = 0; 747 map->busy = 0; 748 } 749 750 void 751 vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) 752 { 753 754 _vm_map_init(map, pmap, min, max); 755 mtx_init(&map->system_mtx, "system map", NULL, MTX_DEF | MTX_DUPOK); 756 sx_init(&map->lock, "user map"); 757 } 758 759 /* 760 * vm_map_entry_dispose: [ internal use only ] 761 * 762 * Inverse of vm_map_entry_create. 763 */ 764 static void 765 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry) 766 { 767 uma_zfree(map->system_map ? kmapentzone : mapentzone, entry); 768 } 769 770 /* 771 * vm_map_entry_create: [ internal use only ] 772 * 773 * Allocates a VM map entry for insertion. 774 * No entry fields are filled in. 775 */ 776 static vm_map_entry_t 777 vm_map_entry_create(vm_map_t map) 778 { 779 vm_map_entry_t new_entry; 780 781 if (map->system_map) 782 new_entry = uma_zalloc(kmapentzone, M_NOWAIT); 783 else 784 new_entry = uma_zalloc(mapentzone, M_WAITOK); 785 if (new_entry == NULL) 786 panic("vm_map_entry_create: kernel resources exhausted"); 787 return (new_entry); 788 } 789 790 /* 791 * vm_map_entry_set_behavior: 792 * 793 * Set the expected access behavior, either normal, random, or 794 * sequential. 795 */ 796 static inline void 797 vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior) 798 { 799 entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) | 800 (behavior & MAP_ENTRY_BEHAV_MASK); 801 } 802 803 /* 804 * vm_map_entry_set_max_free: 805 * 806 * Set the max_free field in a vm_map_entry. 807 */ 808 static inline void 809 vm_map_entry_set_max_free(vm_map_entry_t entry) 810 { 811 812 entry->max_free = entry->adj_free; 813 if (entry->left != NULL && entry->left->max_free > entry->max_free) 814 entry->max_free = entry->left->max_free; 815 if (entry->right != NULL && entry->right->max_free > entry->max_free) 816 entry->max_free = entry->right->max_free; 817 } 818 819 /* 820 * vm_map_entry_splay: 821 * 822 * The Sleator and Tarjan top-down splay algorithm with the 823 * following variation. Max_free must be computed bottom-up, so 824 * on the downward pass, maintain the left and right spines in 825 * reverse order. Then, make a second pass up each side to fix 826 * the pointers and compute max_free. The time bound is O(log n) 827 * amortized. 828 * 829 * The new root is the vm_map_entry containing "addr", or else an 830 * adjacent entry (lower or higher) if addr is not in the tree. 831 * 832 * The map must be locked, and leaves it so. 833 * 834 * Returns: the new root. 835 */ 836 static vm_map_entry_t 837 vm_map_entry_splay(vm_offset_t addr, vm_map_entry_t root) 838 { 839 vm_map_entry_t llist, rlist; 840 vm_map_entry_t ltree, rtree; 841 vm_map_entry_t y; 842 843 /* Special case of empty tree. */ 844 if (root == NULL) 845 return (root); 846 847 /* 848 * Pass One: Splay down the tree until we find addr or a NULL 849 * pointer where addr would go. llist and rlist are the two 850 * sides in reverse order (bottom-up), with llist linked by 851 * the right pointer and rlist linked by the left pointer in 852 * the vm_map_entry. Wait until Pass Two to set max_free on 853 * the two spines. 854 */ 855 llist = NULL; 856 rlist = NULL; 857 for (;;) { 858 /* root is never NULL in here. */ 859 if (addr < root->start) { 860 y = root->left; 861 if (y == NULL) 862 break; 863 if (addr < y->start && y->left != NULL) { 864 /* Rotate right and put y on rlist. */ 865 root->left = y->right; 866 y->right = root; 867 vm_map_entry_set_max_free(root); 868 root = y->left; 869 y->left = rlist; 870 rlist = y; 871 } else { 872 /* Put root on rlist. */ 873 root->left = rlist; 874 rlist = root; 875 root = y; 876 } 877 } else if (addr >= root->end) { 878 y = root->right; 879 if (y == NULL) 880 break; 881 if (addr >= y->end && y->right != NULL) { 882 /* Rotate left and put y on llist. */ 883 root->right = y->left; 884 y->left = root; 885 vm_map_entry_set_max_free(root); 886 root = y->right; 887 y->right = llist; 888 llist = y; 889 } else { 890 /* Put root on llist. */ 891 root->right = llist; 892 llist = root; 893 root = y; 894 } 895 } else 896 break; 897 } 898 899 /* 900 * Pass Two: Walk back up the two spines, flip the pointers 901 * and set max_free. The subtrees of the root go at the 902 * bottom of llist and rlist. 903 */ 904 ltree = root->left; 905 while (llist != NULL) { 906 y = llist->right; 907 llist->right = ltree; 908 vm_map_entry_set_max_free(llist); 909 ltree = llist; 910 llist = y; 911 } 912 rtree = root->right; 913 while (rlist != NULL) { 914 y = rlist->left; 915 rlist->left = rtree; 916 vm_map_entry_set_max_free(rlist); 917 rtree = rlist; 918 rlist = y; 919 } 920 921 /* 922 * Final assembly: add ltree and rtree as subtrees of root. 923 */ 924 root->left = ltree; 925 root->right = rtree; 926 vm_map_entry_set_max_free(root); 927 928 return (root); 929 } 930 931 /* 932 * vm_map_entry_{un,}link: 933 * 934 * Insert/remove entries from maps. 935 */ 936 static void 937 vm_map_entry_link(vm_map_t map, 938 vm_map_entry_t after_where, 939 vm_map_entry_t entry) 940 { 941 942 CTR4(KTR_VM, 943 "vm_map_entry_link: map %p, nentries %d, entry %p, after %p", map, 944 map->nentries, entry, after_where); 945 VM_MAP_ASSERT_LOCKED(map); 946 KASSERT(after_where == &map->header || 947 after_where->end <= entry->start, 948 ("vm_map_entry_link: prev end %jx new start %jx overlap", 949 (uintmax_t)after_where->end, (uintmax_t)entry->start)); 950 KASSERT(after_where->next == &map->header || 951 entry->end <= after_where->next->start, 952 ("vm_map_entry_link: new end %jx next start %jx overlap", 953 (uintmax_t)entry->end, (uintmax_t)after_where->next->start)); 954 955 map->nentries++; 956 entry->prev = after_where; 957 entry->next = after_where->next; 958 entry->next->prev = entry; 959 after_where->next = entry; 960 961 if (after_where != &map->header) { 962 if (after_where != map->root) 963 vm_map_entry_splay(after_where->start, map->root); 964 entry->right = after_where->right; 965 entry->left = after_where; 966 after_where->right = NULL; 967 after_where->adj_free = entry->start - after_where->end; 968 vm_map_entry_set_max_free(after_where); 969 } else { 970 entry->right = map->root; 971 entry->left = NULL; 972 } 973 entry->adj_free = (entry->next == &map->header ? map->max_offset : 974 entry->next->start) - entry->end; 975 vm_map_entry_set_max_free(entry); 976 map->root = entry; 977 } 978 979 static void 980 vm_map_entry_unlink(vm_map_t map, 981 vm_map_entry_t entry) 982 { 983 vm_map_entry_t next, prev, root; 984 985 VM_MAP_ASSERT_LOCKED(map); 986 if (entry != map->root) 987 vm_map_entry_splay(entry->start, map->root); 988 if (entry->left == NULL) 989 root = entry->right; 990 else { 991 root = vm_map_entry_splay(entry->start, entry->left); 992 root->right = entry->right; 993 root->adj_free = (entry->next == &map->header ? map->max_offset : 994 entry->next->start) - root->end; 995 vm_map_entry_set_max_free(root); 996 } 997 map->root = root; 998 999 prev = entry->prev; 1000 next = entry->next; 1001 next->prev = prev; 1002 prev->next = next; 1003 map->nentries--; 1004 CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map, 1005 map->nentries, entry); 1006 } 1007 1008 /* 1009 * vm_map_entry_resize_free: 1010 * 1011 * Recompute the amount of free space following a vm_map_entry 1012 * and propagate that value up the tree. Call this function after 1013 * resizing a map entry in-place, that is, without a call to 1014 * vm_map_entry_link() or _unlink(). 1015 * 1016 * The map must be locked, and leaves it so. 1017 */ 1018 static void 1019 vm_map_entry_resize_free(vm_map_t map, vm_map_entry_t entry) 1020 { 1021 1022 /* 1023 * Using splay trees without parent pointers, propagating 1024 * max_free up the tree is done by moving the entry to the 1025 * root and making the change there. 1026 */ 1027 if (entry != map->root) 1028 map->root = vm_map_entry_splay(entry->start, map->root); 1029 1030 entry->adj_free = (entry->next == &map->header ? map->max_offset : 1031 entry->next->start) - entry->end; 1032 vm_map_entry_set_max_free(entry); 1033 } 1034 1035 /* 1036 * vm_map_lookup_entry: [ internal use only ] 1037 * 1038 * Finds the map entry containing (or 1039 * immediately preceding) the specified address 1040 * in the given map; the entry is returned 1041 * in the "entry" parameter. The boolean 1042 * result indicates whether the address is 1043 * actually contained in the map. 1044 */ 1045 boolean_t 1046 vm_map_lookup_entry( 1047 vm_map_t map, 1048 vm_offset_t address, 1049 vm_map_entry_t *entry) /* OUT */ 1050 { 1051 vm_map_entry_t cur; 1052 boolean_t locked; 1053 1054 /* 1055 * If the map is empty, then the map entry immediately preceding 1056 * "address" is the map's header. 1057 */ 1058 cur = map->root; 1059 if (cur == NULL) 1060 *entry = &map->header; 1061 else if (address >= cur->start && cur->end > address) { 1062 *entry = cur; 1063 return (TRUE); 1064 } else if ((locked = vm_map_locked(map)) || 1065 sx_try_upgrade(&map->lock)) { 1066 /* 1067 * Splay requires a write lock on the map. However, it only 1068 * restructures the binary search tree; it does not otherwise 1069 * change the map. Thus, the map's timestamp need not change 1070 * on a temporary upgrade. 1071 */ 1072 map->root = cur = vm_map_entry_splay(address, cur); 1073 if (!locked) 1074 sx_downgrade(&map->lock); 1075 1076 /* 1077 * If "address" is contained within a map entry, the new root 1078 * is that map entry. Otherwise, the new root is a map entry 1079 * immediately before or after "address". 1080 */ 1081 if (address >= cur->start) { 1082 *entry = cur; 1083 if (cur->end > address) 1084 return (TRUE); 1085 } else 1086 *entry = cur->prev; 1087 } else 1088 /* 1089 * Since the map is only locked for read access, perform a 1090 * standard binary search tree lookup for "address". 1091 */ 1092 for (;;) { 1093 if (address < cur->start) { 1094 if (cur->left == NULL) { 1095 *entry = cur->prev; 1096 break; 1097 } 1098 cur = cur->left; 1099 } else if (cur->end > address) { 1100 *entry = cur; 1101 return (TRUE); 1102 } else { 1103 if (cur->right == NULL) { 1104 *entry = cur; 1105 break; 1106 } 1107 cur = cur->right; 1108 } 1109 } 1110 return (FALSE); 1111 } 1112 1113 /* 1114 * vm_map_insert: 1115 * 1116 * Inserts the given whole VM object into the target 1117 * map at the specified address range. The object's 1118 * size should match that of the address range. 1119 * 1120 * Requires that the map be locked, and leaves it so. 1121 * 1122 * If object is non-NULL, ref count must be bumped by caller 1123 * prior to making call to account for the new entry. 1124 */ 1125 int 1126 vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1127 vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow) 1128 { 1129 vm_map_entry_t new_entry, prev_entry, temp_entry; 1130 vm_eflags_t protoeflags; 1131 struct ucred *cred; 1132 vm_inherit_t inheritance; 1133 1134 VM_MAP_ASSERT_LOCKED(map); 1135 KASSERT((object != kmem_object && object != kernel_object) || 1136 (cow & MAP_COPY_ON_WRITE) == 0, 1137 ("vm_map_insert: kmem or kernel object and COW")); 1138 KASSERT(object == NULL || (cow & MAP_NOFAULT) == 0, 1139 ("vm_map_insert: paradoxical MAP_NOFAULT request")); 1140 1141 /* 1142 * Check that the start and end points are not bogus. 1143 */ 1144 if ((start < map->min_offset) || (end > map->max_offset) || 1145 (start >= end)) 1146 return (KERN_INVALID_ADDRESS); 1147 1148 /* 1149 * Find the entry prior to the proposed starting address; if it's part 1150 * of an existing entry, this range is bogus. 1151 */ 1152 if (vm_map_lookup_entry(map, start, &temp_entry)) 1153 return (KERN_NO_SPACE); 1154 1155 prev_entry = temp_entry; 1156 1157 /* 1158 * Assert that the next entry doesn't overlap the end point. 1159 */ 1160 if ((prev_entry->next != &map->header) && 1161 (prev_entry->next->start < end)) 1162 return (KERN_NO_SPACE); 1163 1164 protoeflags = 0; 1165 if (cow & MAP_COPY_ON_WRITE) 1166 protoeflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY; 1167 if (cow & MAP_NOFAULT) 1168 protoeflags |= MAP_ENTRY_NOFAULT; 1169 if (cow & MAP_DISABLE_SYNCER) 1170 protoeflags |= MAP_ENTRY_NOSYNC; 1171 if (cow & MAP_DISABLE_COREDUMP) 1172 protoeflags |= MAP_ENTRY_NOCOREDUMP; 1173 if (cow & MAP_STACK_GROWS_DOWN) 1174 protoeflags |= MAP_ENTRY_GROWS_DOWN; 1175 if (cow & MAP_STACK_GROWS_UP) 1176 protoeflags |= MAP_ENTRY_GROWS_UP; 1177 if (cow & MAP_VN_WRITECOUNT) 1178 protoeflags |= MAP_ENTRY_VN_WRITECNT; 1179 if (cow & MAP_INHERIT_SHARE) 1180 inheritance = VM_INHERIT_SHARE; 1181 else 1182 inheritance = VM_INHERIT_DEFAULT; 1183 1184 cred = NULL; 1185 if (cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT)) 1186 goto charged; 1187 if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) && 1188 ((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) { 1189 if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start)) 1190 return (KERN_RESOURCE_SHORTAGE); 1191 KASSERT(object == NULL || (protoeflags & MAP_ENTRY_NEEDS_COPY) || 1192 object->cred == NULL, 1193 ("OVERCOMMIT: vm_map_insert o %p", object)); 1194 cred = curthread->td_ucred; 1195 } 1196 1197 charged: 1198 /* Expand the kernel pmap, if necessary. */ 1199 if (map == kernel_map && end > kernel_vm_end) 1200 pmap_growkernel(end); 1201 if (object != NULL) { 1202 /* 1203 * OBJ_ONEMAPPING must be cleared unless this mapping 1204 * is trivially proven to be the only mapping for any 1205 * of the object's pages. (Object granularity 1206 * reference counting is insufficient to recognize 1207 * aliases with precision.) 1208 */ 1209 VM_OBJECT_WLOCK(object); 1210 if (object->ref_count > 1 || object->shadow_count != 0) 1211 vm_object_clear_flag(object, OBJ_ONEMAPPING); 1212 VM_OBJECT_WUNLOCK(object); 1213 } 1214 else if ((prev_entry != &map->header) && 1215 (prev_entry->eflags == protoeflags) && 1216 (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 && 1217 (prev_entry->end == start) && 1218 (prev_entry->wired_count == 0) && 1219 (prev_entry->cred == cred || 1220 (prev_entry->object.vm_object != NULL && 1221 (prev_entry->object.vm_object->cred == cred))) && 1222 vm_object_coalesce(prev_entry->object.vm_object, 1223 prev_entry->offset, 1224 (vm_size_t)(prev_entry->end - prev_entry->start), 1225 (vm_size_t)(end - prev_entry->end), cred != NULL && 1226 (protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)) { 1227 /* 1228 * We were able to extend the object. Determine if we 1229 * can extend the previous map entry to include the 1230 * new range as well. 1231 */ 1232 if ((prev_entry->inheritance == inheritance) && 1233 (prev_entry->protection == prot) && 1234 (prev_entry->max_protection == max)) { 1235 map->size += (end - prev_entry->end); 1236 prev_entry->end = end; 1237 vm_map_entry_resize_free(map, prev_entry); 1238 vm_map_simplify_entry(map, prev_entry); 1239 return (KERN_SUCCESS); 1240 } 1241 1242 /* 1243 * If we can extend the object but cannot extend the 1244 * map entry, we have to create a new map entry. We 1245 * must bump the ref count on the extended object to 1246 * account for it. object may be NULL. 1247 */ 1248 object = prev_entry->object.vm_object; 1249 offset = prev_entry->offset + 1250 (prev_entry->end - prev_entry->start); 1251 vm_object_reference(object); 1252 if (cred != NULL && object != NULL && object->cred != NULL && 1253 !(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { 1254 /* Object already accounts for this uid. */ 1255 cred = NULL; 1256 } 1257 } 1258 if (cred != NULL) 1259 crhold(cred); 1260 1261 /* 1262 * Create a new entry 1263 */ 1264 new_entry = vm_map_entry_create(map); 1265 new_entry->start = start; 1266 new_entry->end = end; 1267 new_entry->cred = NULL; 1268 1269 new_entry->eflags = protoeflags; 1270 new_entry->object.vm_object = object; 1271 new_entry->offset = offset; 1272 new_entry->avail_ssize = 0; 1273 1274 new_entry->inheritance = inheritance; 1275 new_entry->protection = prot; 1276 new_entry->max_protection = max; 1277 new_entry->wired_count = 0; 1278 new_entry->wiring_thread = NULL; 1279 new_entry->read_ahead = VM_FAULT_READ_AHEAD_INIT; 1280 new_entry->next_read = OFF_TO_IDX(offset); 1281 1282 KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry), 1283 ("OVERCOMMIT: vm_map_insert leaks vm_map %p", new_entry)); 1284 new_entry->cred = cred; 1285 1286 /* 1287 * Insert the new entry into the list 1288 */ 1289 vm_map_entry_link(map, prev_entry, new_entry); 1290 map->size += new_entry->end - new_entry->start; 1291 1292 /* 1293 * Try to coalesce the new entry with both the previous and next 1294 * entries in the list. Previously, we only attempted to coalesce 1295 * with the previous entry when object is NULL. Here, we handle the 1296 * other cases, which are less common. 1297 */ 1298 vm_map_simplify_entry(map, new_entry); 1299 1300 if (cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) { 1301 vm_map_pmap_enter(map, start, prot, 1302 object, OFF_TO_IDX(offset), end - start, 1303 cow & MAP_PREFAULT_PARTIAL); 1304 } 1305 1306 return (KERN_SUCCESS); 1307 } 1308 1309 /* 1310 * vm_map_findspace: 1311 * 1312 * Find the first fit (lowest VM address) for "length" free bytes 1313 * beginning at address >= start in the given map. 1314 * 1315 * In a vm_map_entry, "adj_free" is the amount of free space 1316 * adjacent (higher address) to this entry, and "max_free" is the 1317 * maximum amount of contiguous free space in its subtree. This 1318 * allows finding a free region in one path down the tree, so 1319 * O(log n) amortized with splay trees. 1320 * 1321 * The map must be locked, and leaves it so. 1322 * 1323 * Returns: 0 on success, and starting address in *addr, 1324 * 1 if insufficient space. 1325 */ 1326 int 1327 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, 1328 vm_offset_t *addr) /* OUT */ 1329 { 1330 vm_map_entry_t entry; 1331 vm_offset_t st; 1332 1333 /* 1334 * Request must fit within min/max VM address and must avoid 1335 * address wrap. 1336 */ 1337 if (start < map->min_offset) 1338 start = map->min_offset; 1339 if (start + length > map->max_offset || start + length < start) 1340 return (1); 1341 1342 /* Empty tree means wide open address space. */ 1343 if (map->root == NULL) { 1344 *addr = start; 1345 return (0); 1346 } 1347 1348 /* 1349 * After splay, if start comes before root node, then there 1350 * must be a gap from start to the root. 1351 */ 1352 map->root = vm_map_entry_splay(start, map->root); 1353 if (start + length <= map->root->start) { 1354 *addr = start; 1355 return (0); 1356 } 1357 1358 /* 1359 * Root is the last node that might begin its gap before 1360 * start, and this is the last comparison where address 1361 * wrap might be a problem. 1362 */ 1363 st = (start > map->root->end) ? start : map->root->end; 1364 if (length <= map->root->end + map->root->adj_free - st) { 1365 *addr = st; 1366 return (0); 1367 } 1368 1369 /* With max_free, can immediately tell if no solution. */ 1370 entry = map->root->right; 1371 if (entry == NULL || length > entry->max_free) 1372 return (1); 1373 1374 /* 1375 * Search the right subtree in the order: left subtree, root, 1376 * right subtree (first fit). The previous splay implies that 1377 * all regions in the right subtree have addresses > start. 1378 */ 1379 while (entry != NULL) { 1380 if (entry->left != NULL && entry->left->max_free >= length) 1381 entry = entry->left; 1382 else if (entry->adj_free >= length) { 1383 *addr = entry->end; 1384 return (0); 1385 } else 1386 entry = entry->right; 1387 } 1388 1389 /* Can't get here, so panic if we do. */ 1390 panic("vm_map_findspace: max_free corrupt"); 1391 } 1392 1393 int 1394 vm_map_fixed(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1395 vm_offset_t start, vm_size_t length, vm_prot_t prot, 1396 vm_prot_t max, int cow) 1397 { 1398 vm_offset_t end; 1399 int result; 1400 1401 end = start + length; 1402 KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || 1403 object == NULL, 1404 ("vm_map_fixed: non-NULL backing object for stack")); 1405 vm_map_lock(map); 1406 VM_MAP_RANGE_CHECK(map, start, end); 1407 if ((cow & MAP_CHECK_EXCL) == 0) 1408 vm_map_delete(map, start, end); 1409 if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { 1410 result = vm_map_stack_locked(map, start, length, sgrowsiz, 1411 prot, max, cow); 1412 } else { 1413 result = vm_map_insert(map, object, offset, start, end, 1414 prot, max, cow); 1415 } 1416 vm_map_unlock(map); 1417 return (result); 1418 } 1419 1420 /* 1421 * vm_map_find finds an unallocated region in the target address 1422 * map with the given length. The search is defined to be 1423 * first-fit from the specified address; the region found is 1424 * returned in the same parameter. 1425 * 1426 * If object is non-NULL, ref count must be bumped by caller 1427 * prior to making call to account for the new entry. 1428 */ 1429 int 1430 vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1431 vm_offset_t *addr, /* IN/OUT */ 1432 vm_size_t length, vm_offset_t max_addr, int find_space, 1433 vm_prot_t prot, vm_prot_t max, int cow) 1434 { 1435 vm_offset_t alignment, initial_addr, start; 1436 int result; 1437 1438 KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || 1439 object == NULL, 1440 ("vm_map_find: non-NULL backing object for stack")); 1441 if (find_space == VMFS_OPTIMAL_SPACE && (object == NULL || 1442 (object->flags & OBJ_COLORED) == 0)) 1443 find_space = VMFS_ANY_SPACE; 1444 if (find_space >> 8 != 0) { 1445 KASSERT((find_space & 0xff) == 0, ("bad VMFS flags")); 1446 alignment = (vm_offset_t)1 << (find_space >> 8); 1447 } else 1448 alignment = 0; 1449 initial_addr = *addr; 1450 again: 1451 start = initial_addr; 1452 vm_map_lock(map); 1453 do { 1454 if (find_space != VMFS_NO_SPACE) { 1455 if (vm_map_findspace(map, start, length, addr) || 1456 (max_addr != 0 && *addr + length > max_addr)) { 1457 vm_map_unlock(map); 1458 if (find_space == VMFS_OPTIMAL_SPACE) { 1459 find_space = VMFS_ANY_SPACE; 1460 goto again; 1461 } 1462 return (KERN_NO_SPACE); 1463 } 1464 switch (find_space) { 1465 case VMFS_SUPER_SPACE: 1466 case VMFS_OPTIMAL_SPACE: 1467 pmap_align_superpage(object, offset, addr, 1468 length); 1469 break; 1470 case VMFS_ANY_SPACE: 1471 break; 1472 default: 1473 if ((*addr & (alignment - 1)) != 0) { 1474 *addr &= ~(alignment - 1); 1475 *addr += alignment; 1476 } 1477 break; 1478 } 1479 1480 start = *addr; 1481 } 1482 if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { 1483 result = vm_map_stack_locked(map, start, length, 1484 sgrowsiz, prot, max, cow); 1485 } else { 1486 result = vm_map_insert(map, object, offset, start, 1487 start + length, prot, max, cow); 1488 } 1489 } while (result == KERN_NO_SPACE && find_space != VMFS_NO_SPACE && 1490 find_space != VMFS_ANY_SPACE); 1491 vm_map_unlock(map); 1492 return (result); 1493 } 1494 1495 /* 1496 * vm_map_simplify_entry: 1497 * 1498 * Simplify the given map entry by merging with either neighbor. This 1499 * routine also has the ability to merge with both neighbors. 1500 * 1501 * The map must be locked. 1502 * 1503 * This routine guarentees that the passed entry remains valid (though 1504 * possibly extended). When merging, this routine may delete one or 1505 * both neighbors. 1506 */ 1507 void 1508 vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry) 1509 { 1510 vm_map_entry_t next, prev; 1511 vm_size_t prevsize, esize; 1512 1513 if ((entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP | 1514 MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP)) != 0) 1515 return; 1516 1517 prev = entry->prev; 1518 if (prev != &map->header) { 1519 prevsize = prev->end - prev->start; 1520 if ( (prev->end == entry->start) && 1521 (prev->object.vm_object == entry->object.vm_object) && 1522 (!prev->object.vm_object || 1523 (prev->offset + prevsize == entry->offset)) && 1524 (prev->eflags == entry->eflags) && 1525 (prev->protection == entry->protection) && 1526 (prev->max_protection == entry->max_protection) && 1527 (prev->inheritance == entry->inheritance) && 1528 (prev->wired_count == entry->wired_count) && 1529 (prev->cred == entry->cred)) { 1530 vm_map_entry_unlink(map, prev); 1531 entry->start = prev->start; 1532 entry->offset = prev->offset; 1533 if (entry->prev != &map->header) 1534 vm_map_entry_resize_free(map, entry->prev); 1535 1536 /* 1537 * If the backing object is a vnode object, 1538 * vm_object_deallocate() calls vrele(). 1539 * However, vrele() does not lock the vnode 1540 * because the vnode has additional 1541 * references. Thus, the map lock can be kept 1542 * without causing a lock-order reversal with 1543 * the vnode lock. 1544 * 1545 * Since we count the number of virtual page 1546 * mappings in object->un_pager.vnp.writemappings, 1547 * the writemappings value should not be adjusted 1548 * when the entry is disposed of. 1549 */ 1550 if (prev->object.vm_object) 1551 vm_object_deallocate(prev->object.vm_object); 1552 if (prev->cred != NULL) 1553 crfree(prev->cred); 1554 vm_map_entry_dispose(map, prev); 1555 } 1556 } 1557 1558 next = entry->next; 1559 if (next != &map->header) { 1560 esize = entry->end - entry->start; 1561 if ((entry->end == next->start) && 1562 (next->object.vm_object == entry->object.vm_object) && 1563 (!entry->object.vm_object || 1564 (entry->offset + esize == next->offset)) && 1565 (next->eflags == entry->eflags) && 1566 (next->protection == entry->protection) && 1567 (next->max_protection == entry->max_protection) && 1568 (next->inheritance == entry->inheritance) && 1569 (next->wired_count == entry->wired_count) && 1570 (next->cred == entry->cred)) { 1571 vm_map_entry_unlink(map, next); 1572 entry->end = next->end; 1573 vm_map_entry_resize_free(map, entry); 1574 1575 /* 1576 * See comment above. 1577 */ 1578 if (next->object.vm_object) 1579 vm_object_deallocate(next->object.vm_object); 1580 if (next->cred != NULL) 1581 crfree(next->cred); 1582 vm_map_entry_dispose(map, next); 1583 } 1584 } 1585 } 1586 /* 1587 * vm_map_clip_start: [ internal use only ] 1588 * 1589 * Asserts that the given entry begins at or after 1590 * the specified address; if necessary, 1591 * it splits the entry into two. 1592 */ 1593 #define vm_map_clip_start(map, entry, startaddr) \ 1594 { \ 1595 if (startaddr > entry->start) \ 1596 _vm_map_clip_start(map, entry, startaddr); \ 1597 } 1598 1599 /* 1600 * This routine is called only when it is known that 1601 * the entry must be split. 1602 */ 1603 static void 1604 _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start) 1605 { 1606 vm_map_entry_t new_entry; 1607 1608 VM_MAP_ASSERT_LOCKED(map); 1609 1610 /* 1611 * Split off the front portion -- note that we must insert the new 1612 * entry BEFORE this one, so that this entry has the specified 1613 * starting address. 1614 */ 1615 vm_map_simplify_entry(map, entry); 1616 1617 /* 1618 * If there is no object backing this entry, we might as well create 1619 * one now. If we defer it, an object can get created after the map 1620 * is clipped, and individual objects will be created for the split-up 1621 * map. This is a bit of a hack, but is also about the best place to 1622 * put this improvement. 1623 */ 1624 if (entry->object.vm_object == NULL && !map->system_map) { 1625 vm_object_t object; 1626 object = vm_object_allocate(OBJT_DEFAULT, 1627 atop(entry->end - entry->start)); 1628 entry->object.vm_object = object; 1629 entry->offset = 0; 1630 if (entry->cred != NULL) { 1631 object->cred = entry->cred; 1632 object->charge = entry->end - entry->start; 1633 entry->cred = NULL; 1634 } 1635 } else if (entry->object.vm_object != NULL && 1636 ((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) && 1637 entry->cred != NULL) { 1638 VM_OBJECT_WLOCK(entry->object.vm_object); 1639 KASSERT(entry->object.vm_object->cred == NULL, 1640 ("OVERCOMMIT: vm_entry_clip_start: both cred e %p", entry)); 1641 entry->object.vm_object->cred = entry->cred; 1642 entry->object.vm_object->charge = entry->end - entry->start; 1643 VM_OBJECT_WUNLOCK(entry->object.vm_object); 1644 entry->cred = NULL; 1645 } 1646 1647 new_entry = vm_map_entry_create(map); 1648 *new_entry = *entry; 1649 1650 new_entry->end = start; 1651 entry->offset += (start - entry->start); 1652 entry->start = start; 1653 if (new_entry->cred != NULL) 1654 crhold(entry->cred); 1655 1656 vm_map_entry_link(map, entry->prev, new_entry); 1657 1658 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 1659 vm_object_reference(new_entry->object.vm_object); 1660 /* 1661 * The object->un_pager.vnp.writemappings for the 1662 * object of MAP_ENTRY_VN_WRITECNT type entry shall be 1663 * kept as is here. The virtual pages are 1664 * re-distributed among the clipped entries, so the sum is 1665 * left the same. 1666 */ 1667 } 1668 } 1669 1670 /* 1671 * vm_map_clip_end: [ internal use only ] 1672 * 1673 * Asserts that the given entry ends at or before 1674 * the specified address; if necessary, 1675 * it splits the entry into two. 1676 */ 1677 #define vm_map_clip_end(map, entry, endaddr) \ 1678 { \ 1679 if ((endaddr) < (entry->end)) \ 1680 _vm_map_clip_end((map), (entry), (endaddr)); \ 1681 } 1682 1683 /* 1684 * This routine is called only when it is known that 1685 * the entry must be split. 1686 */ 1687 static void 1688 _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end) 1689 { 1690 vm_map_entry_t new_entry; 1691 1692 VM_MAP_ASSERT_LOCKED(map); 1693 1694 /* 1695 * If there is no object backing this entry, we might as well create 1696 * one now. If we defer it, an object can get created after the map 1697 * is clipped, and individual objects will be created for the split-up 1698 * map. This is a bit of a hack, but is also about the best place to 1699 * put this improvement. 1700 */ 1701 if (entry->object.vm_object == NULL && !map->system_map) { 1702 vm_object_t object; 1703 object = vm_object_allocate(OBJT_DEFAULT, 1704 atop(entry->end - entry->start)); 1705 entry->object.vm_object = object; 1706 entry->offset = 0; 1707 if (entry->cred != NULL) { 1708 object->cred = entry->cred; 1709 object->charge = entry->end - entry->start; 1710 entry->cred = NULL; 1711 } 1712 } else if (entry->object.vm_object != NULL && 1713 ((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) && 1714 entry->cred != NULL) { 1715 VM_OBJECT_WLOCK(entry->object.vm_object); 1716 KASSERT(entry->object.vm_object->cred == NULL, 1717 ("OVERCOMMIT: vm_entry_clip_end: both cred e %p", entry)); 1718 entry->object.vm_object->cred = entry->cred; 1719 entry->object.vm_object->charge = entry->end - entry->start; 1720 VM_OBJECT_WUNLOCK(entry->object.vm_object); 1721 entry->cred = NULL; 1722 } 1723 1724 /* 1725 * Create a new entry and insert it AFTER the specified entry 1726 */ 1727 new_entry = vm_map_entry_create(map); 1728 *new_entry = *entry; 1729 1730 new_entry->start = entry->end = end; 1731 new_entry->offset += (end - entry->start); 1732 if (new_entry->cred != NULL) 1733 crhold(entry->cred); 1734 1735 vm_map_entry_link(map, entry, new_entry); 1736 1737 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 1738 vm_object_reference(new_entry->object.vm_object); 1739 } 1740 } 1741 1742 /* 1743 * vm_map_submap: [ kernel use only ] 1744 * 1745 * Mark the given range as handled by a subordinate map. 1746 * 1747 * This range must have been created with vm_map_find, 1748 * and no other operations may have been performed on this 1749 * range prior to calling vm_map_submap. 1750 * 1751 * Only a limited number of operations can be performed 1752 * within this rage after calling vm_map_submap: 1753 * vm_fault 1754 * [Don't try vm_map_copy!] 1755 * 1756 * To remove a submapping, one must first remove the 1757 * range from the superior map, and then destroy the 1758 * submap (if desired). [Better yet, don't try it.] 1759 */ 1760 int 1761 vm_map_submap( 1762 vm_map_t map, 1763 vm_offset_t start, 1764 vm_offset_t end, 1765 vm_map_t submap) 1766 { 1767 vm_map_entry_t entry; 1768 int result = KERN_INVALID_ARGUMENT; 1769 1770 vm_map_lock(map); 1771 1772 VM_MAP_RANGE_CHECK(map, start, end); 1773 1774 if (vm_map_lookup_entry(map, start, &entry)) { 1775 vm_map_clip_start(map, entry, start); 1776 } else 1777 entry = entry->next; 1778 1779 vm_map_clip_end(map, entry, end); 1780 1781 if ((entry->start == start) && (entry->end == end) && 1782 ((entry->eflags & MAP_ENTRY_COW) == 0) && 1783 (entry->object.vm_object == NULL)) { 1784 entry->object.sub_map = submap; 1785 entry->eflags |= MAP_ENTRY_IS_SUB_MAP; 1786 result = KERN_SUCCESS; 1787 } 1788 vm_map_unlock(map); 1789 1790 return (result); 1791 } 1792 1793 /* 1794 * The maximum number of pages to map if MAP_PREFAULT_PARTIAL is specified 1795 */ 1796 #define MAX_INIT_PT 96 1797 1798 /* 1799 * vm_map_pmap_enter: 1800 * 1801 * Preload the specified map's pmap with mappings to the specified 1802 * object's memory-resident pages. No further physical pages are 1803 * allocated, and no further virtual pages are retrieved from secondary 1804 * storage. If the specified flags include MAP_PREFAULT_PARTIAL, then a 1805 * limited number of page mappings are created at the low-end of the 1806 * specified address range. (For this purpose, a superpage mapping 1807 * counts as one page mapping.) Otherwise, all resident pages within 1808 * the specified address range are mapped. Because these mappings are 1809 * being created speculatively, cached pages are not reactivated and 1810 * mapped. 1811 */ 1812 void 1813 vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot, 1814 vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags) 1815 { 1816 vm_offset_t start; 1817 vm_page_t p, p_start; 1818 vm_pindex_t mask, psize, threshold, tmpidx; 1819 1820 if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL) 1821 return; 1822 VM_OBJECT_RLOCK(object); 1823 if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { 1824 VM_OBJECT_RUNLOCK(object); 1825 VM_OBJECT_WLOCK(object); 1826 if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { 1827 pmap_object_init_pt(map->pmap, addr, object, pindex, 1828 size); 1829 VM_OBJECT_WUNLOCK(object); 1830 return; 1831 } 1832 VM_OBJECT_LOCK_DOWNGRADE(object); 1833 } 1834 1835 psize = atop(size); 1836 if (psize + pindex > object->size) { 1837 if (object->size < pindex) { 1838 VM_OBJECT_RUNLOCK(object); 1839 return; 1840 } 1841 psize = object->size - pindex; 1842 } 1843 1844 start = 0; 1845 p_start = NULL; 1846 threshold = MAX_INIT_PT; 1847 1848 p = vm_page_find_least(object, pindex); 1849 /* 1850 * Assert: the variable p is either (1) the page with the 1851 * least pindex greater than or equal to the parameter pindex 1852 * or (2) NULL. 1853 */ 1854 for (; 1855 p != NULL && (tmpidx = p->pindex - pindex) < psize; 1856 p = TAILQ_NEXT(p, listq)) { 1857 /* 1858 * don't allow an madvise to blow away our really 1859 * free pages allocating pv entries. 1860 */ 1861 if (((flags & MAP_PREFAULT_MADVISE) != 0 && 1862 vm_cnt.v_free_count < vm_cnt.v_free_reserved) || 1863 ((flags & MAP_PREFAULT_PARTIAL) != 0 && 1864 tmpidx >= threshold)) { 1865 psize = tmpidx; 1866 break; 1867 } 1868 if (p->valid == VM_PAGE_BITS_ALL) { 1869 if (p_start == NULL) { 1870 start = addr + ptoa(tmpidx); 1871 p_start = p; 1872 } 1873 /* Jump ahead if a superpage mapping is possible. */ 1874 if (p->psind > 0 && ((addr + ptoa(tmpidx)) & 1875 (pagesizes[p->psind] - 1)) == 0) { 1876 mask = atop(pagesizes[p->psind]) - 1; 1877 if (tmpidx + mask < psize && 1878 vm_page_ps_is_valid(p)) { 1879 p += mask; 1880 threshold += mask; 1881 } 1882 } 1883 } else if (p_start != NULL) { 1884 pmap_enter_object(map->pmap, start, addr + 1885 ptoa(tmpidx), p_start, prot); 1886 p_start = NULL; 1887 } 1888 } 1889 if (p_start != NULL) 1890 pmap_enter_object(map->pmap, start, addr + ptoa(psize), 1891 p_start, prot); 1892 VM_OBJECT_RUNLOCK(object); 1893 } 1894 1895 /* 1896 * vm_map_protect: 1897 * 1898 * Sets the protection of the specified address 1899 * region in the target map. If "set_max" is 1900 * specified, the maximum protection is to be set; 1901 * otherwise, only the current protection is affected. 1902 */ 1903 int 1904 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, 1905 vm_prot_t new_prot, boolean_t set_max) 1906 { 1907 vm_map_entry_t current, entry; 1908 vm_object_t obj; 1909 struct ucred *cred; 1910 vm_prot_t old_prot; 1911 1912 if (start == end) 1913 return (KERN_SUCCESS); 1914 1915 vm_map_lock(map); 1916 1917 VM_MAP_RANGE_CHECK(map, start, end); 1918 1919 if (vm_map_lookup_entry(map, start, &entry)) { 1920 vm_map_clip_start(map, entry, start); 1921 } else { 1922 entry = entry->next; 1923 } 1924 1925 /* 1926 * Make a first pass to check for protection violations. 1927 */ 1928 current = entry; 1929 while ((current != &map->header) && (current->start < end)) { 1930 if (current->eflags & MAP_ENTRY_IS_SUB_MAP) { 1931 vm_map_unlock(map); 1932 return (KERN_INVALID_ARGUMENT); 1933 } 1934 if ((new_prot & current->max_protection) != new_prot) { 1935 vm_map_unlock(map); 1936 return (KERN_PROTECTION_FAILURE); 1937 } 1938 current = current->next; 1939 } 1940 1941 1942 /* 1943 * Do an accounting pass for private read-only mappings that 1944 * now will do cow due to allowed write (e.g. debugger sets 1945 * breakpoint on text segment) 1946 */ 1947 for (current = entry; (current != &map->header) && 1948 (current->start < end); current = current->next) { 1949 1950 vm_map_clip_end(map, current, end); 1951 1952 if (set_max || 1953 ((new_prot & ~(current->protection)) & VM_PROT_WRITE) == 0 || 1954 ENTRY_CHARGED(current)) { 1955 continue; 1956 } 1957 1958 cred = curthread->td_ucred; 1959 obj = current->object.vm_object; 1960 1961 if (obj == NULL || (current->eflags & MAP_ENTRY_NEEDS_COPY)) { 1962 if (!swap_reserve(current->end - current->start)) { 1963 vm_map_unlock(map); 1964 return (KERN_RESOURCE_SHORTAGE); 1965 } 1966 crhold(cred); 1967 current->cred = cred; 1968 continue; 1969 } 1970 1971 VM_OBJECT_WLOCK(obj); 1972 if (obj->type != OBJT_DEFAULT && obj->type != OBJT_SWAP) { 1973 VM_OBJECT_WUNLOCK(obj); 1974 continue; 1975 } 1976 1977 /* 1978 * Charge for the whole object allocation now, since 1979 * we cannot distinguish between non-charged and 1980 * charged clipped mapping of the same object later. 1981 */ 1982 KASSERT(obj->charge == 0, 1983 ("vm_map_protect: object %p overcharged (entry %p)", 1984 obj, current)); 1985 if (!swap_reserve(ptoa(obj->size))) { 1986 VM_OBJECT_WUNLOCK(obj); 1987 vm_map_unlock(map); 1988 return (KERN_RESOURCE_SHORTAGE); 1989 } 1990 1991 crhold(cred); 1992 obj->cred = cred; 1993 obj->charge = ptoa(obj->size); 1994 VM_OBJECT_WUNLOCK(obj); 1995 } 1996 1997 /* 1998 * Go back and fix up protections. [Note that clipping is not 1999 * necessary the second time.] 2000 */ 2001 current = entry; 2002 while ((current != &map->header) && (current->start < end)) { 2003 old_prot = current->protection; 2004 2005 if (set_max) 2006 current->protection = 2007 (current->max_protection = new_prot) & 2008 old_prot; 2009 else 2010 current->protection = new_prot; 2011 2012 /* 2013 * For user wired map entries, the normal lazy evaluation of 2014 * write access upgrades through soft page faults is 2015 * undesirable. Instead, immediately copy any pages that are 2016 * copy-on-write and enable write access in the physical map. 2017 */ 2018 if ((current->eflags & MAP_ENTRY_USER_WIRED) != 0 && 2019 (current->protection & VM_PROT_WRITE) != 0 && 2020 (old_prot & VM_PROT_WRITE) == 0) 2021 vm_fault_copy_entry(map, map, current, current, NULL); 2022 2023 /* 2024 * When restricting access, update the physical map. Worry 2025 * about copy-on-write here. 2026 */ 2027 if ((old_prot & ~current->protection) != 0) { 2028 #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ 2029 VM_PROT_ALL) 2030 pmap_protect(map->pmap, current->start, 2031 current->end, 2032 current->protection & MASK(current)); 2033 #undef MASK 2034 } 2035 vm_map_simplify_entry(map, current); 2036 current = current->next; 2037 } 2038 vm_map_unlock(map); 2039 return (KERN_SUCCESS); 2040 } 2041 2042 /* 2043 * vm_map_madvise: 2044 * 2045 * This routine traverses a processes map handling the madvise 2046 * system call. Advisories are classified as either those effecting 2047 * the vm_map_entry structure, or those effecting the underlying 2048 * objects. 2049 */ 2050 int 2051 vm_map_madvise( 2052 vm_map_t map, 2053 vm_offset_t start, 2054 vm_offset_t end, 2055 int behav) 2056 { 2057 vm_map_entry_t current, entry; 2058 int modify_map = 0; 2059 2060 /* 2061 * Some madvise calls directly modify the vm_map_entry, in which case 2062 * we need to use an exclusive lock on the map and we need to perform 2063 * various clipping operations. Otherwise we only need a read-lock 2064 * on the map. 2065 */ 2066 switch(behav) { 2067 case MADV_NORMAL: 2068 case MADV_SEQUENTIAL: 2069 case MADV_RANDOM: 2070 case MADV_NOSYNC: 2071 case MADV_AUTOSYNC: 2072 case MADV_NOCORE: 2073 case MADV_CORE: 2074 if (start == end) 2075 return (KERN_SUCCESS); 2076 modify_map = 1; 2077 vm_map_lock(map); 2078 break; 2079 case MADV_WILLNEED: 2080 case MADV_DONTNEED: 2081 case MADV_FREE: 2082 if (start == end) 2083 return (KERN_SUCCESS); 2084 vm_map_lock_read(map); 2085 break; 2086 default: 2087 return (KERN_INVALID_ARGUMENT); 2088 } 2089 2090 /* 2091 * Locate starting entry and clip if necessary. 2092 */ 2093 VM_MAP_RANGE_CHECK(map, start, end); 2094 2095 if (vm_map_lookup_entry(map, start, &entry)) { 2096 if (modify_map) 2097 vm_map_clip_start(map, entry, start); 2098 } else { 2099 entry = entry->next; 2100 } 2101 2102 if (modify_map) { 2103 /* 2104 * madvise behaviors that are implemented in the vm_map_entry. 2105 * 2106 * We clip the vm_map_entry so that behavioral changes are 2107 * limited to the specified address range. 2108 */ 2109 for (current = entry; 2110 (current != &map->header) && (current->start < end); 2111 current = current->next 2112 ) { 2113 if (current->eflags & MAP_ENTRY_IS_SUB_MAP) 2114 continue; 2115 2116 vm_map_clip_end(map, current, end); 2117 2118 switch (behav) { 2119 case MADV_NORMAL: 2120 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); 2121 break; 2122 case MADV_SEQUENTIAL: 2123 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); 2124 break; 2125 case MADV_RANDOM: 2126 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); 2127 break; 2128 case MADV_NOSYNC: 2129 current->eflags |= MAP_ENTRY_NOSYNC; 2130 break; 2131 case MADV_AUTOSYNC: 2132 current->eflags &= ~MAP_ENTRY_NOSYNC; 2133 break; 2134 case MADV_NOCORE: 2135 current->eflags |= MAP_ENTRY_NOCOREDUMP; 2136 break; 2137 case MADV_CORE: 2138 current->eflags &= ~MAP_ENTRY_NOCOREDUMP; 2139 break; 2140 default: 2141 break; 2142 } 2143 vm_map_simplify_entry(map, current); 2144 } 2145 vm_map_unlock(map); 2146 } else { 2147 vm_pindex_t pstart, pend; 2148 2149 /* 2150 * madvise behaviors that are implemented in the underlying 2151 * vm_object. 2152 * 2153 * Since we don't clip the vm_map_entry, we have to clip 2154 * the vm_object pindex and count. 2155 */ 2156 for (current = entry; 2157 (current != &map->header) && (current->start < end); 2158 current = current->next 2159 ) { 2160 vm_offset_t useEnd, useStart; 2161 2162 if (current->eflags & MAP_ENTRY_IS_SUB_MAP) 2163 continue; 2164 2165 pstart = OFF_TO_IDX(current->offset); 2166 pend = pstart + atop(current->end - current->start); 2167 useStart = current->start; 2168 useEnd = current->end; 2169 2170 if (current->start < start) { 2171 pstart += atop(start - current->start); 2172 useStart = start; 2173 } 2174 if (current->end > end) { 2175 pend -= atop(current->end - end); 2176 useEnd = end; 2177 } 2178 2179 if (pstart >= pend) 2180 continue; 2181 2182 /* 2183 * Perform the pmap_advise() before clearing 2184 * PGA_REFERENCED in vm_page_advise(). Otherwise, a 2185 * concurrent pmap operation, such as pmap_remove(), 2186 * could clear a reference in the pmap and set 2187 * PGA_REFERENCED on the page before the pmap_advise() 2188 * had completed. Consequently, the page would appear 2189 * referenced based upon an old reference that 2190 * occurred before this pmap_advise() ran. 2191 */ 2192 if (behav == MADV_DONTNEED || behav == MADV_FREE) 2193 pmap_advise(map->pmap, useStart, useEnd, 2194 behav); 2195 2196 vm_object_madvise(current->object.vm_object, pstart, 2197 pend, behav); 2198 if (behav == MADV_WILLNEED) { 2199 vm_map_pmap_enter(map, 2200 useStart, 2201 current->protection, 2202 current->object.vm_object, 2203 pstart, 2204 ptoa(pend - pstart), 2205 MAP_PREFAULT_MADVISE 2206 ); 2207 } 2208 } 2209 vm_map_unlock_read(map); 2210 } 2211 return (0); 2212 } 2213 2214 2215 /* 2216 * vm_map_inherit: 2217 * 2218 * Sets the inheritance of the specified address 2219 * range in the target map. Inheritance 2220 * affects how the map will be shared with 2221 * child maps at the time of vmspace_fork. 2222 */ 2223 int 2224 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, 2225 vm_inherit_t new_inheritance) 2226 { 2227 vm_map_entry_t entry; 2228 vm_map_entry_t temp_entry; 2229 2230 switch (new_inheritance) { 2231 case VM_INHERIT_NONE: 2232 case VM_INHERIT_COPY: 2233 case VM_INHERIT_SHARE: 2234 break; 2235 default: 2236 return (KERN_INVALID_ARGUMENT); 2237 } 2238 if (start == end) 2239 return (KERN_SUCCESS); 2240 vm_map_lock(map); 2241 VM_MAP_RANGE_CHECK(map, start, end); 2242 if (vm_map_lookup_entry(map, start, &temp_entry)) { 2243 entry = temp_entry; 2244 vm_map_clip_start(map, entry, start); 2245 } else 2246 entry = temp_entry->next; 2247 while ((entry != &map->header) && (entry->start < end)) { 2248 vm_map_clip_end(map, entry, end); 2249 entry->inheritance = new_inheritance; 2250 vm_map_simplify_entry(map, entry); 2251 entry = entry->next; 2252 } 2253 vm_map_unlock(map); 2254 return (KERN_SUCCESS); 2255 } 2256 2257 /* 2258 * vm_map_unwire: 2259 * 2260 * Implements both kernel and user unwiring. 2261 */ 2262 int 2263 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end, 2264 int flags) 2265 { 2266 vm_map_entry_t entry, first_entry, tmp_entry; 2267 vm_offset_t saved_start; 2268 unsigned int last_timestamp; 2269 int rv; 2270 boolean_t need_wakeup, result, user_unwire; 2271 2272 if (start == end) 2273 return (KERN_SUCCESS); 2274 user_unwire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE; 2275 vm_map_lock(map); 2276 VM_MAP_RANGE_CHECK(map, start, end); 2277 if (!vm_map_lookup_entry(map, start, &first_entry)) { 2278 if (flags & VM_MAP_WIRE_HOLESOK) 2279 first_entry = first_entry->next; 2280 else { 2281 vm_map_unlock(map); 2282 return (KERN_INVALID_ADDRESS); 2283 } 2284 } 2285 last_timestamp = map->timestamp; 2286 entry = first_entry; 2287 while (entry != &map->header && entry->start < end) { 2288 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 2289 /* 2290 * We have not yet clipped the entry. 2291 */ 2292 saved_start = (start >= entry->start) ? start : 2293 entry->start; 2294 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 2295 if (vm_map_unlock_and_wait(map, 0)) { 2296 /* 2297 * Allow interruption of user unwiring? 2298 */ 2299 } 2300 vm_map_lock(map); 2301 if (last_timestamp+1 != map->timestamp) { 2302 /* 2303 * Look again for the entry because the map was 2304 * modified while it was unlocked. 2305 * Specifically, the entry may have been 2306 * clipped, merged, or deleted. 2307 */ 2308 if (!vm_map_lookup_entry(map, saved_start, 2309 &tmp_entry)) { 2310 if (flags & VM_MAP_WIRE_HOLESOK) 2311 tmp_entry = tmp_entry->next; 2312 else { 2313 if (saved_start == start) { 2314 /* 2315 * First_entry has been deleted. 2316 */ 2317 vm_map_unlock(map); 2318 return (KERN_INVALID_ADDRESS); 2319 } 2320 end = saved_start; 2321 rv = KERN_INVALID_ADDRESS; 2322 goto done; 2323 } 2324 } 2325 if (entry == first_entry) 2326 first_entry = tmp_entry; 2327 else 2328 first_entry = NULL; 2329 entry = tmp_entry; 2330 } 2331 last_timestamp = map->timestamp; 2332 continue; 2333 } 2334 vm_map_clip_start(map, entry, start); 2335 vm_map_clip_end(map, entry, end); 2336 /* 2337 * Mark the entry in case the map lock is released. (See 2338 * above.) 2339 */ 2340 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && 2341 entry->wiring_thread == NULL, 2342 ("owned map entry %p", entry)); 2343 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 2344 entry->wiring_thread = curthread; 2345 /* 2346 * Check the map for holes in the specified region. 2347 * If VM_MAP_WIRE_HOLESOK was specified, skip this check. 2348 */ 2349 if (((flags & VM_MAP_WIRE_HOLESOK) == 0) && 2350 (entry->end < end && (entry->next == &map->header || 2351 entry->next->start > entry->end))) { 2352 end = entry->end; 2353 rv = KERN_INVALID_ADDRESS; 2354 goto done; 2355 } 2356 /* 2357 * If system unwiring, require that the entry is system wired. 2358 */ 2359 if (!user_unwire && 2360 vm_map_entry_system_wired_count(entry) == 0) { 2361 end = entry->end; 2362 rv = KERN_INVALID_ARGUMENT; 2363 goto done; 2364 } 2365 entry = entry->next; 2366 } 2367 rv = KERN_SUCCESS; 2368 done: 2369 need_wakeup = FALSE; 2370 if (first_entry == NULL) { 2371 result = vm_map_lookup_entry(map, start, &first_entry); 2372 if (!result && (flags & VM_MAP_WIRE_HOLESOK)) 2373 first_entry = first_entry->next; 2374 else 2375 KASSERT(result, ("vm_map_unwire: lookup failed")); 2376 } 2377 for (entry = first_entry; entry != &map->header && entry->start < end; 2378 entry = entry->next) { 2379 /* 2380 * If VM_MAP_WIRE_HOLESOK was specified, an empty 2381 * space in the unwired region could have been mapped 2382 * while the map lock was dropped for draining 2383 * MAP_ENTRY_IN_TRANSITION. Moreover, another thread 2384 * could be simultaneously wiring this new mapping 2385 * entry. Detect these cases and skip any entries 2386 * marked as in transition by us. 2387 */ 2388 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || 2389 entry->wiring_thread != curthread) { 2390 KASSERT((flags & VM_MAP_WIRE_HOLESOK) != 0, 2391 ("vm_map_unwire: !HOLESOK and new/changed entry")); 2392 continue; 2393 } 2394 2395 if (rv == KERN_SUCCESS && (!user_unwire || 2396 (entry->eflags & MAP_ENTRY_USER_WIRED))) { 2397 if (user_unwire) 2398 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2399 if (entry->wired_count == 1) 2400 vm_map_entry_unwire(map, entry); 2401 else 2402 entry->wired_count--; 2403 } 2404 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, 2405 ("vm_map_unwire: in-transition flag missing %p", entry)); 2406 KASSERT(entry->wiring_thread == curthread, 2407 ("vm_map_unwire: alien wire %p", entry)); 2408 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; 2409 entry->wiring_thread = NULL; 2410 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 2411 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 2412 need_wakeup = TRUE; 2413 } 2414 vm_map_simplify_entry(map, entry); 2415 } 2416 vm_map_unlock(map); 2417 if (need_wakeup) 2418 vm_map_wakeup(map); 2419 return (rv); 2420 } 2421 2422 /* 2423 * vm_map_wire_entry_failure: 2424 * 2425 * Handle a wiring failure on the given entry. 2426 * 2427 * The map should be locked. 2428 */ 2429 static void 2430 vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, 2431 vm_offset_t failed_addr) 2432 { 2433 2434 VM_MAP_ASSERT_LOCKED(map); 2435 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 && 2436 entry->wired_count == 1, 2437 ("vm_map_wire_entry_failure: entry %p isn't being wired", entry)); 2438 KASSERT(failed_addr < entry->end, 2439 ("vm_map_wire_entry_failure: entry %p was fully wired", entry)); 2440 2441 /* 2442 * If any pages at the start of this entry were successfully wired, 2443 * then unwire them. 2444 */ 2445 if (failed_addr > entry->start) { 2446 pmap_unwire(map->pmap, entry->start, failed_addr); 2447 vm_object_unwire(entry->object.vm_object, entry->offset, 2448 failed_addr - entry->start, PQ_ACTIVE); 2449 } 2450 2451 /* 2452 * Assign an out-of-range value to represent the failure to wire this 2453 * entry. 2454 */ 2455 entry->wired_count = -1; 2456 } 2457 2458 /* 2459 * vm_map_wire: 2460 * 2461 * Implements both kernel and user wiring. 2462 */ 2463 int 2464 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, 2465 int flags) 2466 { 2467 vm_map_entry_t entry, first_entry, tmp_entry; 2468 vm_offset_t faddr, saved_end, saved_start; 2469 unsigned int last_timestamp; 2470 int rv; 2471 boolean_t need_wakeup, result, user_wire; 2472 vm_prot_t prot; 2473 2474 if (start == end) 2475 return (KERN_SUCCESS); 2476 prot = 0; 2477 if (flags & VM_MAP_WIRE_WRITE) 2478 prot |= VM_PROT_WRITE; 2479 user_wire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE; 2480 vm_map_lock(map); 2481 VM_MAP_RANGE_CHECK(map, start, end); 2482 if (!vm_map_lookup_entry(map, start, &first_entry)) { 2483 if (flags & VM_MAP_WIRE_HOLESOK) 2484 first_entry = first_entry->next; 2485 else { 2486 vm_map_unlock(map); 2487 return (KERN_INVALID_ADDRESS); 2488 } 2489 } 2490 last_timestamp = map->timestamp; 2491 entry = first_entry; 2492 while (entry != &map->header && entry->start < end) { 2493 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 2494 /* 2495 * We have not yet clipped the entry. 2496 */ 2497 saved_start = (start >= entry->start) ? start : 2498 entry->start; 2499 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 2500 if (vm_map_unlock_and_wait(map, 0)) { 2501 /* 2502 * Allow interruption of user wiring? 2503 */ 2504 } 2505 vm_map_lock(map); 2506 if (last_timestamp + 1 != map->timestamp) { 2507 /* 2508 * Look again for the entry because the map was 2509 * modified while it was unlocked. 2510 * Specifically, the entry may have been 2511 * clipped, merged, or deleted. 2512 */ 2513 if (!vm_map_lookup_entry(map, saved_start, 2514 &tmp_entry)) { 2515 if (flags & VM_MAP_WIRE_HOLESOK) 2516 tmp_entry = tmp_entry->next; 2517 else { 2518 if (saved_start == start) { 2519 /* 2520 * first_entry has been deleted. 2521 */ 2522 vm_map_unlock(map); 2523 return (KERN_INVALID_ADDRESS); 2524 } 2525 end = saved_start; 2526 rv = KERN_INVALID_ADDRESS; 2527 goto done; 2528 } 2529 } 2530 if (entry == first_entry) 2531 first_entry = tmp_entry; 2532 else 2533 first_entry = NULL; 2534 entry = tmp_entry; 2535 } 2536 last_timestamp = map->timestamp; 2537 continue; 2538 } 2539 vm_map_clip_start(map, entry, start); 2540 vm_map_clip_end(map, entry, end); 2541 /* 2542 * Mark the entry in case the map lock is released. (See 2543 * above.) 2544 */ 2545 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && 2546 entry->wiring_thread == NULL, 2547 ("owned map entry %p", entry)); 2548 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 2549 entry->wiring_thread = curthread; 2550 if ((entry->protection & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 2551 || (entry->protection & prot) != prot) { 2552 entry->eflags |= MAP_ENTRY_WIRE_SKIPPED; 2553 if ((flags & VM_MAP_WIRE_HOLESOK) == 0) { 2554 end = entry->end; 2555 rv = KERN_INVALID_ADDRESS; 2556 goto done; 2557 } 2558 goto next_entry; 2559 } 2560 if (entry->wired_count == 0) { 2561 entry->wired_count++; 2562 saved_start = entry->start; 2563 saved_end = entry->end; 2564 2565 /* 2566 * Release the map lock, relying on the in-transition 2567 * mark. Mark the map busy for fork. 2568 */ 2569 vm_map_busy(map); 2570 vm_map_unlock(map); 2571 2572 faddr = saved_start; 2573 do { 2574 /* 2575 * Simulate a fault to get the page and enter 2576 * it into the physical map. 2577 */ 2578 if ((rv = vm_fault(map, faddr, VM_PROT_NONE, 2579 VM_FAULT_CHANGE_WIRING)) != KERN_SUCCESS) 2580 break; 2581 } while ((faddr += PAGE_SIZE) < saved_end); 2582 vm_map_lock(map); 2583 vm_map_unbusy(map); 2584 if (last_timestamp + 1 != map->timestamp) { 2585 /* 2586 * Look again for the entry because the map was 2587 * modified while it was unlocked. The entry 2588 * may have been clipped, but NOT merged or 2589 * deleted. 2590 */ 2591 result = vm_map_lookup_entry(map, saved_start, 2592 &tmp_entry); 2593 KASSERT(result, ("vm_map_wire: lookup failed")); 2594 if (entry == first_entry) 2595 first_entry = tmp_entry; 2596 else 2597 first_entry = NULL; 2598 entry = tmp_entry; 2599 while (entry->end < saved_end) { 2600 /* 2601 * In case of failure, handle entries 2602 * that were not fully wired here; 2603 * fully wired entries are handled 2604 * later. 2605 */ 2606 if (rv != KERN_SUCCESS && 2607 faddr < entry->end) 2608 vm_map_wire_entry_failure(map, 2609 entry, faddr); 2610 entry = entry->next; 2611 } 2612 } 2613 last_timestamp = map->timestamp; 2614 if (rv != KERN_SUCCESS) { 2615 vm_map_wire_entry_failure(map, entry, faddr); 2616 end = entry->end; 2617 goto done; 2618 } 2619 } else if (!user_wire || 2620 (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 2621 entry->wired_count++; 2622 } 2623 /* 2624 * Check the map for holes in the specified region. 2625 * If VM_MAP_WIRE_HOLESOK was specified, skip this check. 2626 */ 2627 next_entry: 2628 if (((flags & VM_MAP_WIRE_HOLESOK) == 0) && 2629 (entry->end < end && (entry->next == &map->header || 2630 entry->next->start > entry->end))) { 2631 end = entry->end; 2632 rv = KERN_INVALID_ADDRESS; 2633 goto done; 2634 } 2635 entry = entry->next; 2636 } 2637 rv = KERN_SUCCESS; 2638 done: 2639 need_wakeup = FALSE; 2640 if (first_entry == NULL) { 2641 result = vm_map_lookup_entry(map, start, &first_entry); 2642 if (!result && (flags & VM_MAP_WIRE_HOLESOK)) 2643 first_entry = first_entry->next; 2644 else 2645 KASSERT(result, ("vm_map_wire: lookup failed")); 2646 } 2647 for (entry = first_entry; entry != &map->header && entry->start < end; 2648 entry = entry->next) { 2649 if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0) 2650 goto next_entry_done; 2651 2652 /* 2653 * If VM_MAP_WIRE_HOLESOK was specified, an empty 2654 * space in the unwired region could have been mapped 2655 * while the map lock was dropped for faulting in the 2656 * pages or draining MAP_ENTRY_IN_TRANSITION. 2657 * Moreover, another thread could be simultaneously 2658 * wiring this new mapping entry. Detect these cases 2659 * and skip any entries marked as in transition by us. 2660 */ 2661 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || 2662 entry->wiring_thread != curthread) { 2663 KASSERT((flags & VM_MAP_WIRE_HOLESOK) != 0, 2664 ("vm_map_wire: !HOLESOK and new/changed entry")); 2665 continue; 2666 } 2667 2668 if (rv == KERN_SUCCESS) { 2669 if (user_wire) 2670 entry->eflags |= MAP_ENTRY_USER_WIRED; 2671 } else if (entry->wired_count == -1) { 2672 /* 2673 * Wiring failed on this entry. Thus, unwiring is 2674 * unnecessary. 2675 */ 2676 entry->wired_count = 0; 2677 } else if (!user_wire || 2678 (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 2679 /* 2680 * Undo the wiring. Wiring succeeded on this entry 2681 * but failed on a later entry. 2682 */ 2683 if (entry->wired_count == 1) 2684 vm_map_entry_unwire(map, entry); 2685 else 2686 entry->wired_count--; 2687 } 2688 next_entry_done: 2689 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, 2690 ("vm_map_wire: in-transition flag missing %p", entry)); 2691 KASSERT(entry->wiring_thread == curthread, 2692 ("vm_map_wire: alien wire %p", entry)); 2693 entry->eflags &= ~(MAP_ENTRY_IN_TRANSITION | 2694 MAP_ENTRY_WIRE_SKIPPED); 2695 entry->wiring_thread = NULL; 2696 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 2697 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 2698 need_wakeup = TRUE; 2699 } 2700 vm_map_simplify_entry(map, entry); 2701 } 2702 vm_map_unlock(map); 2703 if (need_wakeup) 2704 vm_map_wakeup(map); 2705 return (rv); 2706 } 2707 2708 /* 2709 * vm_map_sync 2710 * 2711 * Push any dirty cached pages in the address range to their pager. 2712 * If syncio is TRUE, dirty pages are written synchronously. 2713 * If invalidate is TRUE, any cached pages are freed as well. 2714 * 2715 * If the size of the region from start to end is zero, we are 2716 * supposed to flush all modified pages within the region containing 2717 * start. Unfortunately, a region can be split or coalesced with 2718 * neighboring regions, making it difficult to determine what the 2719 * original region was. Therefore, we approximate this requirement by 2720 * flushing the current region containing start. 2721 * 2722 * Returns an error if any part of the specified range is not mapped. 2723 */ 2724 int 2725 vm_map_sync( 2726 vm_map_t map, 2727 vm_offset_t start, 2728 vm_offset_t end, 2729 boolean_t syncio, 2730 boolean_t invalidate) 2731 { 2732 vm_map_entry_t current; 2733 vm_map_entry_t entry; 2734 vm_size_t size; 2735 vm_object_t object; 2736 vm_ooffset_t offset; 2737 unsigned int last_timestamp; 2738 boolean_t failed; 2739 2740 vm_map_lock_read(map); 2741 VM_MAP_RANGE_CHECK(map, start, end); 2742 if (!vm_map_lookup_entry(map, start, &entry)) { 2743 vm_map_unlock_read(map); 2744 return (KERN_INVALID_ADDRESS); 2745 } else if (start == end) { 2746 start = entry->start; 2747 end = entry->end; 2748 } 2749 /* 2750 * Make a first pass to check for user-wired memory and holes. 2751 */ 2752 for (current = entry; current != &map->header && current->start < end; 2753 current = current->next) { 2754 if (invalidate && (current->eflags & MAP_ENTRY_USER_WIRED)) { 2755 vm_map_unlock_read(map); 2756 return (KERN_INVALID_ARGUMENT); 2757 } 2758 if (end > current->end && 2759 (current->next == &map->header || 2760 current->end != current->next->start)) { 2761 vm_map_unlock_read(map); 2762 return (KERN_INVALID_ADDRESS); 2763 } 2764 } 2765 2766 if (invalidate) 2767 pmap_remove(map->pmap, start, end); 2768 failed = FALSE; 2769 2770 /* 2771 * Make a second pass, cleaning/uncaching pages from the indicated 2772 * objects as we go. 2773 */ 2774 for (current = entry; current != &map->header && current->start < end;) { 2775 offset = current->offset + (start - current->start); 2776 size = (end <= current->end ? end : current->end) - start; 2777 if (current->eflags & MAP_ENTRY_IS_SUB_MAP) { 2778 vm_map_t smap; 2779 vm_map_entry_t tentry; 2780 vm_size_t tsize; 2781 2782 smap = current->object.sub_map; 2783 vm_map_lock_read(smap); 2784 (void) vm_map_lookup_entry(smap, offset, &tentry); 2785 tsize = tentry->end - offset; 2786 if (tsize < size) 2787 size = tsize; 2788 object = tentry->object.vm_object; 2789 offset = tentry->offset + (offset - tentry->start); 2790 vm_map_unlock_read(smap); 2791 } else { 2792 object = current->object.vm_object; 2793 } 2794 vm_object_reference(object); 2795 last_timestamp = map->timestamp; 2796 vm_map_unlock_read(map); 2797 if (!vm_object_sync(object, offset, size, syncio, invalidate)) 2798 failed = TRUE; 2799 start += size; 2800 vm_object_deallocate(object); 2801 vm_map_lock_read(map); 2802 if (last_timestamp == map->timestamp || 2803 !vm_map_lookup_entry(map, start, ¤t)) 2804 current = current->next; 2805 } 2806 2807 vm_map_unlock_read(map); 2808 return (failed ? KERN_FAILURE : KERN_SUCCESS); 2809 } 2810 2811 /* 2812 * vm_map_entry_unwire: [ internal use only ] 2813 * 2814 * Make the region specified by this entry pageable. 2815 * 2816 * The map in question should be locked. 2817 * [This is the reason for this routine's existence.] 2818 */ 2819 static void 2820 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) 2821 { 2822 2823 VM_MAP_ASSERT_LOCKED(map); 2824 KASSERT(entry->wired_count > 0, 2825 ("vm_map_entry_unwire: entry %p isn't wired", entry)); 2826 pmap_unwire(map->pmap, entry->start, entry->end); 2827 vm_object_unwire(entry->object.vm_object, entry->offset, entry->end - 2828 entry->start, PQ_ACTIVE); 2829 entry->wired_count = 0; 2830 } 2831 2832 static void 2833 vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map) 2834 { 2835 2836 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) 2837 vm_object_deallocate(entry->object.vm_object); 2838 uma_zfree(system_map ? kmapentzone : mapentzone, entry); 2839 } 2840 2841 /* 2842 * vm_map_entry_delete: [ internal use only ] 2843 * 2844 * Deallocate the given entry from the target map. 2845 */ 2846 static void 2847 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry) 2848 { 2849 vm_object_t object; 2850 vm_pindex_t offidxstart, offidxend, count, size1; 2851 vm_ooffset_t size; 2852 2853 vm_map_entry_unlink(map, entry); 2854 object = entry->object.vm_object; 2855 size = entry->end - entry->start; 2856 map->size -= size; 2857 2858 if (entry->cred != NULL) { 2859 swap_release_by_cred(size, entry->cred); 2860 crfree(entry->cred); 2861 } 2862 2863 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0 && 2864 (object != NULL)) { 2865 KASSERT(entry->cred == NULL || object->cred == NULL || 2866 (entry->eflags & MAP_ENTRY_NEEDS_COPY), 2867 ("OVERCOMMIT vm_map_entry_delete: both cred %p", entry)); 2868 count = OFF_TO_IDX(size); 2869 offidxstart = OFF_TO_IDX(entry->offset); 2870 offidxend = offidxstart + count; 2871 VM_OBJECT_WLOCK(object); 2872 if (object->ref_count != 1 && 2873 ((object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING || 2874 object == kernel_object || object == kmem_object)) { 2875 vm_object_collapse(object); 2876 2877 /* 2878 * The option OBJPR_NOTMAPPED can be passed here 2879 * because vm_map_delete() already performed 2880 * pmap_remove() on the only mapping to this range 2881 * of pages. 2882 */ 2883 vm_object_page_remove(object, offidxstart, offidxend, 2884 OBJPR_NOTMAPPED); 2885 if (object->type == OBJT_SWAP) 2886 swap_pager_freespace(object, offidxstart, count); 2887 if (offidxend >= object->size && 2888 offidxstart < object->size) { 2889 size1 = object->size; 2890 object->size = offidxstart; 2891 if (object->cred != NULL) { 2892 size1 -= object->size; 2893 KASSERT(object->charge >= ptoa(size1), 2894 ("vm_map_entry_delete: object->charge < 0")); 2895 swap_release_by_cred(ptoa(size1), object->cred); 2896 object->charge -= ptoa(size1); 2897 } 2898 } 2899 } 2900 VM_OBJECT_WUNLOCK(object); 2901 } else 2902 entry->object.vm_object = NULL; 2903 if (map->system_map) 2904 vm_map_entry_deallocate(entry, TRUE); 2905 else { 2906 entry->next = curthread->td_map_def_user; 2907 curthread->td_map_def_user = entry; 2908 } 2909 } 2910 2911 /* 2912 * vm_map_delete: [ internal use only ] 2913 * 2914 * Deallocates the given address range from the target 2915 * map. 2916 */ 2917 int 2918 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end) 2919 { 2920 vm_map_entry_t entry; 2921 vm_map_entry_t first_entry; 2922 2923 VM_MAP_ASSERT_LOCKED(map); 2924 if (start == end) 2925 return (KERN_SUCCESS); 2926 2927 /* 2928 * Find the start of the region, and clip it 2929 */ 2930 if (!vm_map_lookup_entry(map, start, &first_entry)) 2931 entry = first_entry->next; 2932 else { 2933 entry = first_entry; 2934 vm_map_clip_start(map, entry, start); 2935 } 2936 2937 /* 2938 * Step through all entries in this region 2939 */ 2940 while ((entry != &map->header) && (entry->start < end)) { 2941 vm_map_entry_t next; 2942 2943 /* 2944 * Wait for wiring or unwiring of an entry to complete. 2945 * Also wait for any system wirings to disappear on 2946 * user maps. 2947 */ 2948 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 || 2949 (vm_map_pmap(map) != kernel_pmap && 2950 vm_map_entry_system_wired_count(entry) != 0)) { 2951 unsigned int last_timestamp; 2952 vm_offset_t saved_start; 2953 vm_map_entry_t tmp_entry; 2954 2955 saved_start = entry->start; 2956 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 2957 last_timestamp = map->timestamp; 2958 (void) vm_map_unlock_and_wait(map, 0); 2959 vm_map_lock(map); 2960 if (last_timestamp + 1 != map->timestamp) { 2961 /* 2962 * Look again for the entry because the map was 2963 * modified while it was unlocked. 2964 * Specifically, the entry may have been 2965 * clipped, merged, or deleted. 2966 */ 2967 if (!vm_map_lookup_entry(map, saved_start, 2968 &tmp_entry)) 2969 entry = tmp_entry->next; 2970 else { 2971 entry = tmp_entry; 2972 vm_map_clip_start(map, entry, 2973 saved_start); 2974 } 2975 } 2976 continue; 2977 } 2978 vm_map_clip_end(map, entry, end); 2979 2980 next = entry->next; 2981 2982 /* 2983 * Unwire before removing addresses from the pmap; otherwise, 2984 * unwiring will put the entries back in the pmap. 2985 */ 2986 if (entry->wired_count != 0) { 2987 vm_map_entry_unwire(map, entry); 2988 } 2989 2990 pmap_remove(map->pmap, entry->start, entry->end); 2991 2992 /* 2993 * Delete the entry only after removing all pmap 2994 * entries pointing to its pages. (Otherwise, its 2995 * page frames may be reallocated, and any modify bits 2996 * will be set in the wrong object!) 2997 */ 2998 vm_map_entry_delete(map, entry); 2999 entry = next; 3000 } 3001 return (KERN_SUCCESS); 3002 } 3003 3004 /* 3005 * vm_map_remove: 3006 * 3007 * Remove the given address range from the target map. 3008 * This is the exported form of vm_map_delete. 3009 */ 3010 int 3011 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) 3012 { 3013 int result; 3014 3015 vm_map_lock(map); 3016 VM_MAP_RANGE_CHECK(map, start, end); 3017 result = vm_map_delete(map, start, end); 3018 vm_map_unlock(map); 3019 return (result); 3020 } 3021 3022 /* 3023 * vm_map_check_protection: 3024 * 3025 * Assert that the target map allows the specified privilege on the 3026 * entire address region given. The entire region must be allocated. 3027 * 3028 * WARNING! This code does not and should not check whether the 3029 * contents of the region is accessible. For example a smaller file 3030 * might be mapped into a larger address space. 3031 * 3032 * NOTE! This code is also called by munmap(). 3033 * 3034 * The map must be locked. A read lock is sufficient. 3035 */ 3036 boolean_t 3037 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, 3038 vm_prot_t protection) 3039 { 3040 vm_map_entry_t entry; 3041 vm_map_entry_t tmp_entry; 3042 3043 if (!vm_map_lookup_entry(map, start, &tmp_entry)) 3044 return (FALSE); 3045 entry = tmp_entry; 3046 3047 while (start < end) { 3048 if (entry == &map->header) 3049 return (FALSE); 3050 /* 3051 * No holes allowed! 3052 */ 3053 if (start < entry->start) 3054 return (FALSE); 3055 /* 3056 * Check protection associated with entry. 3057 */ 3058 if ((entry->protection & protection) != protection) 3059 return (FALSE); 3060 /* go to next entry */ 3061 start = entry->end; 3062 entry = entry->next; 3063 } 3064 return (TRUE); 3065 } 3066 3067 /* 3068 * vm_map_copy_entry: 3069 * 3070 * Copies the contents of the source entry to the destination 3071 * entry. The entries *must* be aligned properly. 3072 */ 3073 static void 3074 vm_map_copy_entry( 3075 vm_map_t src_map, 3076 vm_map_t dst_map, 3077 vm_map_entry_t src_entry, 3078 vm_map_entry_t dst_entry, 3079 vm_ooffset_t *fork_charge) 3080 { 3081 vm_object_t src_object; 3082 vm_map_entry_t fake_entry; 3083 vm_offset_t size; 3084 struct ucred *cred; 3085 int charged; 3086 3087 VM_MAP_ASSERT_LOCKED(dst_map); 3088 3089 if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP) 3090 return; 3091 3092 if (src_entry->wired_count == 0 || 3093 (src_entry->protection & VM_PROT_WRITE) == 0) { 3094 /* 3095 * If the source entry is marked needs_copy, it is already 3096 * write-protected. 3097 */ 3098 if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0 && 3099 (src_entry->protection & VM_PROT_WRITE) != 0) { 3100 pmap_protect(src_map->pmap, 3101 src_entry->start, 3102 src_entry->end, 3103 src_entry->protection & ~VM_PROT_WRITE); 3104 } 3105 3106 /* 3107 * Make a copy of the object. 3108 */ 3109 size = src_entry->end - src_entry->start; 3110 if ((src_object = src_entry->object.vm_object) != NULL) { 3111 VM_OBJECT_WLOCK(src_object); 3112 charged = ENTRY_CHARGED(src_entry); 3113 if ((src_object->handle == NULL) && 3114 (src_object->type == OBJT_DEFAULT || 3115 src_object->type == OBJT_SWAP)) { 3116 vm_object_collapse(src_object); 3117 if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) { 3118 vm_object_split(src_entry); 3119 src_object = src_entry->object.vm_object; 3120 } 3121 } 3122 vm_object_reference_locked(src_object); 3123 vm_object_clear_flag(src_object, OBJ_ONEMAPPING); 3124 if (src_entry->cred != NULL && 3125 !(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { 3126 KASSERT(src_object->cred == NULL, 3127 ("OVERCOMMIT: vm_map_copy_entry: cred %p", 3128 src_object)); 3129 src_object->cred = src_entry->cred; 3130 src_object->charge = size; 3131 } 3132 VM_OBJECT_WUNLOCK(src_object); 3133 dst_entry->object.vm_object = src_object; 3134 if (charged) { 3135 cred = curthread->td_ucred; 3136 crhold(cred); 3137 dst_entry->cred = cred; 3138 *fork_charge += size; 3139 if (!(src_entry->eflags & 3140 MAP_ENTRY_NEEDS_COPY)) { 3141 crhold(cred); 3142 src_entry->cred = cred; 3143 *fork_charge += size; 3144 } 3145 } 3146 src_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); 3147 dst_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); 3148 dst_entry->offset = src_entry->offset; 3149 if (src_entry->eflags & MAP_ENTRY_VN_WRITECNT) { 3150 /* 3151 * MAP_ENTRY_VN_WRITECNT cannot 3152 * indicate write reference from 3153 * src_entry, since the entry is 3154 * marked as needs copy. Allocate a 3155 * fake entry that is used to 3156 * decrement object->un_pager.vnp.writecount 3157 * at the appropriate time. Attach 3158 * fake_entry to the deferred list. 3159 */ 3160 fake_entry = vm_map_entry_create(dst_map); 3161 fake_entry->eflags = MAP_ENTRY_VN_WRITECNT; 3162 src_entry->eflags &= ~MAP_ENTRY_VN_WRITECNT; 3163 vm_object_reference(src_object); 3164 fake_entry->object.vm_object = src_object; 3165 fake_entry->start = src_entry->start; 3166 fake_entry->end = src_entry->end; 3167 fake_entry->next = curthread->td_map_def_user; 3168 curthread->td_map_def_user = fake_entry; 3169 } 3170 } else { 3171 dst_entry->object.vm_object = NULL; 3172 dst_entry->offset = 0; 3173 if (src_entry->cred != NULL) { 3174 dst_entry->cred = curthread->td_ucred; 3175 crhold(dst_entry->cred); 3176 *fork_charge += size; 3177 } 3178 } 3179 3180 pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start, 3181 dst_entry->end - dst_entry->start, src_entry->start); 3182 } else { 3183 /* 3184 * We don't want to make writeable wired pages copy-on-write. 3185 * Immediately copy these pages into the new map by simulating 3186 * page faults. The new pages are pageable. 3187 */ 3188 vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry, 3189 fork_charge); 3190 } 3191 } 3192 3193 /* 3194 * vmspace_map_entry_forked: 3195 * Update the newly-forked vmspace each time a map entry is inherited 3196 * or copied. The values for vm_dsize and vm_tsize are approximate 3197 * (and mostly-obsolete ideas in the face of mmap(2) et al.) 3198 */ 3199 static void 3200 vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2, 3201 vm_map_entry_t entry) 3202 { 3203 vm_size_t entrysize; 3204 vm_offset_t newend; 3205 3206 entrysize = entry->end - entry->start; 3207 vm2->vm_map.size += entrysize; 3208 if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) { 3209 vm2->vm_ssize += btoc(entrysize); 3210 } else if (entry->start >= (vm_offset_t)vm1->vm_daddr && 3211 entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) { 3212 newend = MIN(entry->end, 3213 (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)); 3214 vm2->vm_dsize += btoc(newend - entry->start); 3215 } else if (entry->start >= (vm_offset_t)vm1->vm_taddr && 3216 entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) { 3217 newend = MIN(entry->end, 3218 (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)); 3219 vm2->vm_tsize += btoc(newend - entry->start); 3220 } 3221 } 3222 3223 /* 3224 * vmspace_fork: 3225 * Create a new process vmspace structure and vm_map 3226 * based on those of an existing process. The new map 3227 * is based on the old map, according to the inheritance 3228 * values on the regions in that map. 3229 * 3230 * XXX It might be worth coalescing the entries added to the new vmspace. 3231 * 3232 * The source map must not be locked. 3233 */ 3234 struct vmspace * 3235 vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge) 3236 { 3237 struct vmspace *vm2; 3238 vm_map_t new_map, old_map; 3239 vm_map_entry_t new_entry, old_entry; 3240 vm_object_t object; 3241 int locked; 3242 3243 old_map = &vm1->vm_map; 3244 /* Copy immutable fields of vm1 to vm2. */ 3245 vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset, NULL); 3246 if (vm2 == NULL) 3247 return (NULL); 3248 vm2->vm_taddr = vm1->vm_taddr; 3249 vm2->vm_daddr = vm1->vm_daddr; 3250 vm2->vm_maxsaddr = vm1->vm_maxsaddr; 3251 vm_map_lock(old_map); 3252 if (old_map->busy) 3253 vm_map_wait_busy(old_map); 3254 new_map = &vm2->vm_map; 3255 locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */ 3256 KASSERT(locked, ("vmspace_fork: lock failed")); 3257 3258 old_entry = old_map->header.next; 3259 3260 while (old_entry != &old_map->header) { 3261 if (old_entry->eflags & MAP_ENTRY_IS_SUB_MAP) 3262 panic("vm_map_fork: encountered a submap"); 3263 3264 switch (old_entry->inheritance) { 3265 case VM_INHERIT_NONE: 3266 break; 3267 3268 case VM_INHERIT_SHARE: 3269 /* 3270 * Clone the entry, creating the shared object if necessary. 3271 */ 3272 object = old_entry->object.vm_object; 3273 if (object == NULL) { 3274 object = vm_object_allocate(OBJT_DEFAULT, 3275 atop(old_entry->end - old_entry->start)); 3276 old_entry->object.vm_object = object; 3277 old_entry->offset = 0; 3278 if (old_entry->cred != NULL) { 3279 object->cred = old_entry->cred; 3280 object->charge = old_entry->end - 3281 old_entry->start; 3282 old_entry->cred = NULL; 3283 } 3284 } 3285 3286 /* 3287 * Add the reference before calling vm_object_shadow 3288 * to insure that a shadow object is created. 3289 */ 3290 vm_object_reference(object); 3291 if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3292 vm_object_shadow(&old_entry->object.vm_object, 3293 &old_entry->offset, 3294 old_entry->end - old_entry->start); 3295 old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 3296 /* Transfer the second reference too. */ 3297 vm_object_reference( 3298 old_entry->object.vm_object); 3299 3300 /* 3301 * As in vm_map_simplify_entry(), the 3302 * vnode lock will not be acquired in 3303 * this call to vm_object_deallocate(). 3304 */ 3305 vm_object_deallocate(object); 3306 object = old_entry->object.vm_object; 3307 } 3308 VM_OBJECT_WLOCK(object); 3309 vm_object_clear_flag(object, OBJ_ONEMAPPING); 3310 if (old_entry->cred != NULL) { 3311 KASSERT(object->cred == NULL, ("vmspace_fork both cred")); 3312 object->cred = old_entry->cred; 3313 object->charge = old_entry->end - old_entry->start; 3314 old_entry->cred = NULL; 3315 } 3316 3317 /* 3318 * Assert the correct state of the vnode 3319 * v_writecount while the object is locked, to 3320 * not relock it later for the assertion 3321 * correctness. 3322 */ 3323 if (old_entry->eflags & MAP_ENTRY_VN_WRITECNT && 3324 object->type == OBJT_VNODE) { 3325 KASSERT(((struct vnode *)object->handle)-> 3326 v_writecount > 0, 3327 ("vmspace_fork: v_writecount %p", object)); 3328 KASSERT(object->un_pager.vnp.writemappings > 0, 3329 ("vmspace_fork: vnp.writecount %p", 3330 object)); 3331 } 3332 VM_OBJECT_WUNLOCK(object); 3333 3334 /* 3335 * Clone the entry, referencing the shared object. 3336 */ 3337 new_entry = vm_map_entry_create(new_map); 3338 *new_entry = *old_entry; 3339 new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | 3340 MAP_ENTRY_IN_TRANSITION); 3341 new_entry->wiring_thread = NULL; 3342 new_entry->wired_count = 0; 3343 if (new_entry->eflags & MAP_ENTRY_VN_WRITECNT) { 3344 vnode_pager_update_writecount(object, 3345 new_entry->start, new_entry->end); 3346 } 3347 3348 /* 3349 * Insert the entry into the new map -- we know we're 3350 * inserting at the end of the new map. 3351 */ 3352 vm_map_entry_link(new_map, new_map->header.prev, 3353 new_entry); 3354 vmspace_map_entry_forked(vm1, vm2, new_entry); 3355 3356 /* 3357 * Update the physical map 3358 */ 3359 pmap_copy(new_map->pmap, old_map->pmap, 3360 new_entry->start, 3361 (old_entry->end - old_entry->start), 3362 old_entry->start); 3363 break; 3364 3365 case VM_INHERIT_COPY: 3366 /* 3367 * Clone the entry and link into the map. 3368 */ 3369 new_entry = vm_map_entry_create(new_map); 3370 *new_entry = *old_entry; 3371 /* 3372 * Copied entry is COW over the old object. 3373 */ 3374 new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | 3375 MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_VN_WRITECNT); 3376 new_entry->wiring_thread = NULL; 3377 new_entry->wired_count = 0; 3378 new_entry->object.vm_object = NULL; 3379 new_entry->cred = NULL; 3380 vm_map_entry_link(new_map, new_map->header.prev, 3381 new_entry); 3382 vmspace_map_entry_forked(vm1, vm2, new_entry); 3383 vm_map_copy_entry(old_map, new_map, old_entry, 3384 new_entry, fork_charge); 3385 break; 3386 } 3387 old_entry = old_entry->next; 3388 } 3389 /* 3390 * Use inlined vm_map_unlock() to postpone handling the deferred 3391 * map entries, which cannot be done until both old_map and 3392 * new_map locks are released. 3393 */ 3394 sx_xunlock(&old_map->lock); 3395 sx_xunlock(&new_map->lock); 3396 vm_map_process_deferred(); 3397 3398 return (vm2); 3399 } 3400 3401 int 3402 vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, 3403 vm_prot_t prot, vm_prot_t max, int cow) 3404 { 3405 vm_size_t growsize, init_ssize; 3406 rlim_t lmemlim, vmemlim; 3407 int rv; 3408 3409 growsize = sgrowsiz; 3410 init_ssize = (max_ssize < growsize) ? max_ssize : growsize; 3411 vm_map_lock(map); 3412 PROC_LOCK(curproc); 3413 lmemlim = lim_cur(curproc, RLIMIT_MEMLOCK); 3414 vmemlim = lim_cur(curproc, RLIMIT_VMEM); 3415 PROC_UNLOCK(curproc); 3416 if (!old_mlock && map->flags & MAP_WIREFUTURE) { 3417 if (ptoa(pmap_wired_count(map->pmap)) + init_ssize > lmemlim) { 3418 rv = KERN_NO_SPACE; 3419 goto out; 3420 } 3421 } 3422 /* If we would blow our VMEM resource limit, no go */ 3423 if (map->size + init_ssize > vmemlim) { 3424 rv = KERN_NO_SPACE; 3425 goto out; 3426 } 3427 rv = vm_map_stack_locked(map, addrbos, max_ssize, growsize, prot, 3428 max, cow); 3429 out: 3430 vm_map_unlock(map); 3431 return (rv); 3432 } 3433 3434 static int 3435 vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, 3436 vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow) 3437 { 3438 vm_map_entry_t new_entry, prev_entry; 3439 vm_offset_t bot, top; 3440 vm_size_t init_ssize; 3441 int orient, rv; 3442 3443 /* 3444 * The stack orientation is piggybacked with the cow argument. 3445 * Extract it into orient and mask the cow argument so that we 3446 * don't pass it around further. 3447 * NOTE: We explicitly allow bi-directional stacks. 3448 */ 3449 orient = cow & (MAP_STACK_GROWS_DOWN|MAP_STACK_GROWS_UP); 3450 KASSERT(orient != 0, ("No stack grow direction")); 3451 3452 if (addrbos < vm_map_min(map) || 3453 addrbos > vm_map_max(map) || 3454 addrbos + max_ssize < addrbos) 3455 return (KERN_NO_SPACE); 3456 3457 init_ssize = (max_ssize < growsize) ? max_ssize : growsize; 3458 3459 /* If addr is already mapped, no go */ 3460 if (vm_map_lookup_entry(map, addrbos, &prev_entry)) 3461 return (KERN_NO_SPACE); 3462 3463 /* 3464 * If we can't accomodate max_ssize in the current mapping, no go. 3465 * However, we need to be aware that subsequent user mappings might 3466 * map into the space we have reserved for stack, and currently this 3467 * space is not protected. 3468 * 3469 * Hopefully we will at least detect this condition when we try to 3470 * grow the stack. 3471 */ 3472 if ((prev_entry->next != &map->header) && 3473 (prev_entry->next->start < addrbos + max_ssize)) 3474 return (KERN_NO_SPACE); 3475 3476 /* 3477 * We initially map a stack of only init_ssize. We will grow as 3478 * needed later. Depending on the orientation of the stack (i.e. 3479 * the grow direction) we either map at the top of the range, the 3480 * bottom of the range or in the middle. 3481 * 3482 * Note: we would normally expect prot and max to be VM_PROT_ALL, 3483 * and cow to be 0. Possibly we should eliminate these as input 3484 * parameters, and just pass these values here in the insert call. 3485 */ 3486 if (orient == MAP_STACK_GROWS_DOWN) 3487 bot = addrbos + max_ssize - init_ssize; 3488 else if (orient == MAP_STACK_GROWS_UP) 3489 bot = addrbos; 3490 else 3491 bot = round_page(addrbos + max_ssize/2 - init_ssize/2); 3492 top = bot + init_ssize; 3493 rv = vm_map_insert(map, NULL, 0, bot, top, prot, max, cow); 3494 3495 /* Now set the avail_ssize amount. */ 3496 if (rv == KERN_SUCCESS) { 3497 new_entry = prev_entry->next; 3498 if (new_entry->end != top || new_entry->start != bot) 3499 panic("Bad entry start/end for new stack entry"); 3500 3501 new_entry->avail_ssize = max_ssize - init_ssize; 3502 KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 || 3503 (new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0, 3504 ("new entry lacks MAP_ENTRY_GROWS_DOWN")); 3505 KASSERT((orient & MAP_STACK_GROWS_UP) == 0 || 3506 (new_entry->eflags & MAP_ENTRY_GROWS_UP) != 0, 3507 ("new entry lacks MAP_ENTRY_GROWS_UP")); 3508 } 3509 3510 return (rv); 3511 } 3512 3513 static int stack_guard_page = 0; 3514 SYSCTL_INT(_security_bsd, OID_AUTO, stack_guard_page, CTLFLAG_RWTUN, 3515 &stack_guard_page, 0, 3516 "Insert stack guard page ahead of the growable segments."); 3517 3518 /* Attempts to grow a vm stack entry. Returns KERN_SUCCESS if the 3519 * desired address is already mapped, or if we successfully grow 3520 * the stack. Also returns KERN_SUCCESS if addr is outside the 3521 * stack range (this is strange, but preserves compatibility with 3522 * the grow function in vm_machdep.c). 3523 */ 3524 int 3525 vm_map_growstack(struct proc *p, vm_offset_t addr) 3526 { 3527 vm_map_entry_t next_entry, prev_entry; 3528 vm_map_entry_t new_entry, stack_entry; 3529 struct vmspace *vm = p->p_vmspace; 3530 vm_map_t map = &vm->vm_map; 3531 vm_offset_t end; 3532 vm_size_t growsize; 3533 size_t grow_amount, max_grow; 3534 rlim_t lmemlim, stacklim, vmemlim; 3535 int is_procstack, rv; 3536 struct ucred *cred; 3537 #ifdef notyet 3538 uint64_t limit; 3539 #endif 3540 #ifdef RACCT 3541 int error; 3542 #endif 3543 3544 Retry: 3545 PROC_LOCK(p); 3546 lmemlim = lim_cur(p, RLIMIT_MEMLOCK); 3547 stacklim = lim_cur(p, RLIMIT_STACK); 3548 vmemlim = lim_cur(p, RLIMIT_VMEM); 3549 PROC_UNLOCK(p); 3550 3551 vm_map_lock_read(map); 3552 3553 /* If addr is already in the entry range, no need to grow.*/ 3554 if (vm_map_lookup_entry(map, addr, &prev_entry)) { 3555 vm_map_unlock_read(map); 3556 return (KERN_SUCCESS); 3557 } 3558 3559 next_entry = prev_entry->next; 3560 if (!(prev_entry->eflags & MAP_ENTRY_GROWS_UP)) { 3561 /* 3562 * This entry does not grow upwards. Since the address lies 3563 * beyond this entry, the next entry (if one exists) has to 3564 * be a downward growable entry. The entry list header is 3565 * never a growable entry, so it suffices to check the flags. 3566 */ 3567 if (!(next_entry->eflags & MAP_ENTRY_GROWS_DOWN)) { 3568 vm_map_unlock_read(map); 3569 return (KERN_SUCCESS); 3570 } 3571 stack_entry = next_entry; 3572 } else { 3573 /* 3574 * This entry grows upward. If the next entry does not at 3575 * least grow downwards, this is the entry we need to grow. 3576 * otherwise we have two possible choices and we have to 3577 * select one. 3578 */ 3579 if (next_entry->eflags & MAP_ENTRY_GROWS_DOWN) { 3580 /* 3581 * We have two choices; grow the entry closest to 3582 * the address to minimize the amount of growth. 3583 */ 3584 if (addr - prev_entry->end <= next_entry->start - addr) 3585 stack_entry = prev_entry; 3586 else 3587 stack_entry = next_entry; 3588 } else 3589 stack_entry = prev_entry; 3590 } 3591 3592 if (stack_entry == next_entry) { 3593 KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_DOWN, ("foo")); 3594 KASSERT(addr < stack_entry->start, ("foo")); 3595 end = (prev_entry != &map->header) ? prev_entry->end : 3596 stack_entry->start - stack_entry->avail_ssize; 3597 grow_amount = roundup(stack_entry->start - addr, PAGE_SIZE); 3598 max_grow = stack_entry->start - end; 3599 } else { 3600 KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_UP, ("foo")); 3601 KASSERT(addr >= stack_entry->end, ("foo")); 3602 end = (next_entry != &map->header) ? next_entry->start : 3603 stack_entry->end + stack_entry->avail_ssize; 3604 grow_amount = roundup(addr + 1 - stack_entry->end, PAGE_SIZE); 3605 max_grow = end - stack_entry->end; 3606 } 3607 3608 if (grow_amount > stack_entry->avail_ssize) { 3609 vm_map_unlock_read(map); 3610 return (KERN_NO_SPACE); 3611 } 3612 3613 /* 3614 * If there is no longer enough space between the entries nogo, and 3615 * adjust the available space. Note: this should only happen if the 3616 * user has mapped into the stack area after the stack was created, 3617 * and is probably an error. 3618 * 3619 * This also effectively destroys any guard page the user might have 3620 * intended by limiting the stack size. 3621 */ 3622 if (grow_amount + (stack_guard_page ? PAGE_SIZE : 0) > max_grow) { 3623 if (vm_map_lock_upgrade(map)) 3624 goto Retry; 3625 3626 stack_entry->avail_ssize = max_grow; 3627 3628 vm_map_unlock(map); 3629 return (KERN_NO_SPACE); 3630 } 3631 3632 is_procstack = (addr >= (vm_offset_t)vm->vm_maxsaddr) ? 1 : 0; 3633 3634 /* 3635 * If this is the main process stack, see if we're over the stack 3636 * limit. 3637 */ 3638 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) { 3639 vm_map_unlock_read(map); 3640 return (KERN_NO_SPACE); 3641 } 3642 #ifdef RACCT 3643 PROC_LOCK(p); 3644 if (is_procstack && 3645 racct_set(p, RACCT_STACK, ctob(vm->vm_ssize) + grow_amount)) { 3646 PROC_UNLOCK(p); 3647 vm_map_unlock_read(map); 3648 return (KERN_NO_SPACE); 3649 } 3650 PROC_UNLOCK(p); 3651 #endif 3652 3653 /* Round up the grow amount modulo sgrowsiz */ 3654 growsize = sgrowsiz; 3655 grow_amount = roundup(grow_amount, growsize); 3656 if (grow_amount > stack_entry->avail_ssize) 3657 grow_amount = stack_entry->avail_ssize; 3658 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) { 3659 grow_amount = trunc_page((vm_size_t)stacklim) - 3660 ctob(vm->vm_ssize); 3661 } 3662 #ifdef notyet 3663 PROC_LOCK(p); 3664 limit = racct_get_available(p, RACCT_STACK); 3665 PROC_UNLOCK(p); 3666 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > limit)) 3667 grow_amount = limit - ctob(vm->vm_ssize); 3668 #endif 3669 if (!old_mlock && map->flags & MAP_WIREFUTURE) { 3670 if (ptoa(pmap_wired_count(map->pmap)) + grow_amount > lmemlim) { 3671 vm_map_unlock_read(map); 3672 rv = KERN_NO_SPACE; 3673 goto out; 3674 } 3675 #ifdef RACCT 3676 PROC_LOCK(p); 3677 if (racct_set(p, RACCT_MEMLOCK, 3678 ptoa(pmap_wired_count(map->pmap)) + grow_amount)) { 3679 PROC_UNLOCK(p); 3680 vm_map_unlock_read(map); 3681 rv = KERN_NO_SPACE; 3682 goto out; 3683 } 3684 PROC_UNLOCK(p); 3685 #endif 3686 } 3687 /* If we would blow our VMEM resource limit, no go */ 3688 if (map->size + grow_amount > vmemlim) { 3689 vm_map_unlock_read(map); 3690 rv = KERN_NO_SPACE; 3691 goto out; 3692 } 3693 #ifdef RACCT 3694 PROC_LOCK(p); 3695 if (racct_set(p, RACCT_VMEM, map->size + grow_amount)) { 3696 PROC_UNLOCK(p); 3697 vm_map_unlock_read(map); 3698 rv = KERN_NO_SPACE; 3699 goto out; 3700 } 3701 PROC_UNLOCK(p); 3702 #endif 3703 3704 if (vm_map_lock_upgrade(map)) 3705 goto Retry; 3706 3707 if (stack_entry == next_entry) { 3708 /* 3709 * Growing downward. 3710 */ 3711 /* Get the preliminary new entry start value */ 3712 addr = stack_entry->start - grow_amount; 3713 3714 /* 3715 * If this puts us into the previous entry, cut back our 3716 * growth to the available space. Also, see the note above. 3717 */ 3718 if (addr < end) { 3719 stack_entry->avail_ssize = max_grow; 3720 addr = end; 3721 if (stack_guard_page) 3722 addr += PAGE_SIZE; 3723 } 3724 3725 rv = vm_map_insert(map, NULL, 0, addr, stack_entry->start, 3726 next_entry->protection, next_entry->max_protection, 3727 MAP_STACK_GROWS_DOWN); 3728 3729 /* Adjust the available stack space by the amount we grew. */ 3730 if (rv == KERN_SUCCESS) { 3731 new_entry = prev_entry->next; 3732 KASSERT(new_entry == stack_entry->prev, ("foo")); 3733 KASSERT(new_entry->end == stack_entry->start, ("foo")); 3734 KASSERT(new_entry->start == addr, ("foo")); 3735 KASSERT((new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 3736 0, ("new entry lacks MAP_ENTRY_GROWS_DOWN")); 3737 grow_amount = new_entry->end - new_entry->start; 3738 new_entry->avail_ssize = stack_entry->avail_ssize - 3739 grow_amount; 3740 stack_entry->eflags &= ~MAP_ENTRY_GROWS_DOWN; 3741 } 3742 } else { 3743 /* 3744 * Growing upward. 3745 */ 3746 addr = stack_entry->end + grow_amount; 3747 3748 /* 3749 * If this puts us into the next entry, cut back our growth 3750 * to the available space. Also, see the note above. 3751 */ 3752 if (addr > end) { 3753 stack_entry->avail_ssize = end - stack_entry->end; 3754 addr = end; 3755 if (stack_guard_page) 3756 addr -= PAGE_SIZE; 3757 } 3758 3759 grow_amount = addr - stack_entry->end; 3760 cred = stack_entry->cred; 3761 if (cred == NULL && stack_entry->object.vm_object != NULL) 3762 cred = stack_entry->object.vm_object->cred; 3763 if (cred != NULL && !swap_reserve_by_cred(grow_amount, cred)) 3764 rv = KERN_NO_SPACE; 3765 /* Grow the underlying object if applicable. */ 3766 else if (stack_entry->object.vm_object == NULL || 3767 vm_object_coalesce(stack_entry->object.vm_object, 3768 stack_entry->offset, 3769 (vm_size_t)(stack_entry->end - stack_entry->start), 3770 (vm_size_t)grow_amount, cred != NULL)) { 3771 map->size += (addr - stack_entry->end); 3772 /* Update the current entry. */ 3773 stack_entry->end = addr; 3774 stack_entry->avail_ssize -= grow_amount; 3775 vm_map_entry_resize_free(map, stack_entry); 3776 rv = KERN_SUCCESS; 3777 } else 3778 rv = KERN_FAILURE; 3779 } 3780 3781 if (rv == KERN_SUCCESS && is_procstack) 3782 vm->vm_ssize += btoc(grow_amount); 3783 3784 vm_map_unlock(map); 3785 3786 /* 3787 * Heed the MAP_WIREFUTURE flag if it was set for this process. 3788 */ 3789 if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE)) { 3790 vm_map_wire(map, 3791 (stack_entry == next_entry) ? addr : addr - grow_amount, 3792 (stack_entry == next_entry) ? stack_entry->start : addr, 3793 (p->p_flag & P_SYSTEM) 3794 ? VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES 3795 : VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES); 3796 } 3797 3798 out: 3799 #ifdef RACCT 3800 if (rv != KERN_SUCCESS) { 3801 PROC_LOCK(p); 3802 error = racct_set(p, RACCT_VMEM, map->size); 3803 KASSERT(error == 0, ("decreasing RACCT_VMEM failed")); 3804 if (!old_mlock) { 3805 error = racct_set(p, RACCT_MEMLOCK, 3806 ptoa(pmap_wired_count(map->pmap))); 3807 KASSERT(error == 0, ("decreasing RACCT_MEMLOCK failed")); 3808 } 3809 error = racct_set(p, RACCT_STACK, ctob(vm->vm_ssize)); 3810 KASSERT(error == 0, ("decreasing RACCT_STACK failed")); 3811 PROC_UNLOCK(p); 3812 } 3813 #endif 3814 3815 return (rv); 3816 } 3817 3818 /* 3819 * Unshare the specified VM space for exec. If other processes are 3820 * mapped to it, then create a new one. The new vmspace is null. 3821 */ 3822 int 3823 vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser) 3824 { 3825 struct vmspace *oldvmspace = p->p_vmspace; 3826 struct vmspace *newvmspace; 3827 3828 KASSERT((curthread->td_pflags & TDP_EXECVMSPC) == 0, 3829 ("vmspace_exec recursed")); 3830 newvmspace = vmspace_alloc(minuser, maxuser, NULL); 3831 if (newvmspace == NULL) 3832 return (ENOMEM); 3833 newvmspace->vm_swrss = oldvmspace->vm_swrss; 3834 /* 3835 * This code is written like this for prototype purposes. The 3836 * goal is to avoid running down the vmspace here, but let the 3837 * other process's that are still using the vmspace to finally 3838 * run it down. Even though there is little or no chance of blocking 3839 * here, it is a good idea to keep this form for future mods. 3840 */ 3841 PROC_VMSPACE_LOCK(p); 3842 p->p_vmspace = newvmspace; 3843 PROC_VMSPACE_UNLOCK(p); 3844 if (p == curthread->td_proc) 3845 pmap_activate(curthread); 3846 curthread->td_pflags |= TDP_EXECVMSPC; 3847 return (0); 3848 } 3849 3850 /* 3851 * Unshare the specified VM space for forcing COW. This 3852 * is called by rfork, for the (RFMEM|RFPROC) == 0 case. 3853 */ 3854 int 3855 vmspace_unshare(struct proc *p) 3856 { 3857 struct vmspace *oldvmspace = p->p_vmspace; 3858 struct vmspace *newvmspace; 3859 vm_ooffset_t fork_charge; 3860 3861 if (oldvmspace->vm_refcnt == 1) 3862 return (0); 3863 fork_charge = 0; 3864 newvmspace = vmspace_fork(oldvmspace, &fork_charge); 3865 if (newvmspace == NULL) 3866 return (ENOMEM); 3867 if (!swap_reserve_by_cred(fork_charge, p->p_ucred)) { 3868 vmspace_free(newvmspace); 3869 return (ENOMEM); 3870 } 3871 PROC_VMSPACE_LOCK(p); 3872 p->p_vmspace = newvmspace; 3873 PROC_VMSPACE_UNLOCK(p); 3874 if (p == curthread->td_proc) 3875 pmap_activate(curthread); 3876 vmspace_free(oldvmspace); 3877 return (0); 3878 } 3879 3880 /* 3881 * vm_map_lookup: 3882 * 3883 * Finds the VM object, offset, and 3884 * protection for a given virtual address in the 3885 * specified map, assuming a page fault of the 3886 * type specified. 3887 * 3888 * Leaves the map in question locked for read; return 3889 * values are guaranteed until a vm_map_lookup_done 3890 * call is performed. Note that the map argument 3891 * is in/out; the returned map must be used in 3892 * the call to vm_map_lookup_done. 3893 * 3894 * A handle (out_entry) is returned for use in 3895 * vm_map_lookup_done, to make that fast. 3896 * 3897 * If a lookup is requested with "write protection" 3898 * specified, the map may be changed to perform virtual 3899 * copying operations, although the data referenced will 3900 * remain the same. 3901 */ 3902 int 3903 vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ 3904 vm_offset_t vaddr, 3905 vm_prot_t fault_typea, 3906 vm_map_entry_t *out_entry, /* OUT */ 3907 vm_object_t *object, /* OUT */ 3908 vm_pindex_t *pindex, /* OUT */ 3909 vm_prot_t *out_prot, /* OUT */ 3910 boolean_t *wired) /* OUT */ 3911 { 3912 vm_map_entry_t entry; 3913 vm_map_t map = *var_map; 3914 vm_prot_t prot; 3915 vm_prot_t fault_type = fault_typea; 3916 vm_object_t eobject; 3917 vm_size_t size; 3918 struct ucred *cred; 3919 3920 RetryLookup:; 3921 3922 vm_map_lock_read(map); 3923 3924 /* 3925 * Lookup the faulting address. 3926 */ 3927 if (!vm_map_lookup_entry(map, vaddr, out_entry)) { 3928 vm_map_unlock_read(map); 3929 return (KERN_INVALID_ADDRESS); 3930 } 3931 3932 entry = *out_entry; 3933 3934 /* 3935 * Handle submaps. 3936 */ 3937 if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 3938 vm_map_t old_map = map; 3939 3940 *var_map = map = entry->object.sub_map; 3941 vm_map_unlock_read(old_map); 3942 goto RetryLookup; 3943 } 3944 3945 /* 3946 * Check whether this task is allowed to have this page. 3947 */ 3948 prot = entry->protection; 3949 fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 3950 if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) { 3951 vm_map_unlock_read(map); 3952 return (KERN_PROTECTION_FAILURE); 3953 } 3954 if ((entry->eflags & MAP_ENTRY_USER_WIRED) && 3955 (entry->eflags & MAP_ENTRY_COW) && 3956 (fault_type & VM_PROT_WRITE)) { 3957 vm_map_unlock_read(map); 3958 return (KERN_PROTECTION_FAILURE); 3959 } 3960 if ((fault_typea & VM_PROT_COPY) != 0 && 3961 (entry->max_protection & VM_PROT_WRITE) == 0 && 3962 (entry->eflags & MAP_ENTRY_COW) == 0) { 3963 vm_map_unlock_read(map); 3964 return (KERN_PROTECTION_FAILURE); 3965 } 3966 3967 /* 3968 * If this page is not pageable, we have to get it for all possible 3969 * accesses. 3970 */ 3971 *wired = (entry->wired_count != 0); 3972 if (*wired) 3973 fault_type = entry->protection; 3974 size = entry->end - entry->start; 3975 /* 3976 * If the entry was copy-on-write, we either ... 3977 */ 3978 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3979 /* 3980 * If we want to write the page, we may as well handle that 3981 * now since we've got the map locked. 3982 * 3983 * If we don't need to write the page, we just demote the 3984 * permissions allowed. 3985 */ 3986 if ((fault_type & VM_PROT_WRITE) != 0 || 3987 (fault_typea & VM_PROT_COPY) != 0) { 3988 /* 3989 * Make a new object, and place it in the object 3990 * chain. Note that no new references have appeared 3991 * -- one just moved from the map to the new 3992 * object. 3993 */ 3994 if (vm_map_lock_upgrade(map)) 3995 goto RetryLookup; 3996 3997 if (entry->cred == NULL) { 3998 /* 3999 * The debugger owner is charged for 4000 * the memory. 4001 */ 4002 cred = curthread->td_ucred; 4003 crhold(cred); 4004 if (!swap_reserve_by_cred(size, cred)) { 4005 crfree(cred); 4006 vm_map_unlock(map); 4007 return (KERN_RESOURCE_SHORTAGE); 4008 } 4009 entry->cred = cred; 4010 } 4011 vm_object_shadow(&entry->object.vm_object, 4012 &entry->offset, size); 4013 entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 4014 eobject = entry->object.vm_object; 4015 if (eobject->cred != NULL) { 4016 /* 4017 * The object was not shadowed. 4018 */ 4019 swap_release_by_cred(size, entry->cred); 4020 crfree(entry->cred); 4021 entry->cred = NULL; 4022 } else if (entry->cred != NULL) { 4023 VM_OBJECT_WLOCK(eobject); 4024 eobject->cred = entry->cred; 4025 eobject->charge = size; 4026 VM_OBJECT_WUNLOCK(eobject); 4027 entry->cred = NULL; 4028 } 4029 4030 vm_map_lock_downgrade(map); 4031 } else { 4032 /* 4033 * We're attempting to read a copy-on-write page -- 4034 * don't allow writes. 4035 */ 4036 prot &= ~VM_PROT_WRITE; 4037 } 4038 } 4039 4040 /* 4041 * Create an object if necessary. 4042 */ 4043 if (entry->object.vm_object == NULL && 4044 !map->system_map) { 4045 if (vm_map_lock_upgrade(map)) 4046 goto RetryLookup; 4047 entry->object.vm_object = vm_object_allocate(OBJT_DEFAULT, 4048 atop(size)); 4049 entry->offset = 0; 4050 if (entry->cred != NULL) { 4051 VM_OBJECT_WLOCK(entry->object.vm_object); 4052 entry->object.vm_object->cred = entry->cred; 4053 entry->object.vm_object->charge = size; 4054 VM_OBJECT_WUNLOCK(entry->object.vm_object); 4055 entry->cred = NULL; 4056 } 4057 vm_map_lock_downgrade(map); 4058 } 4059 4060 /* 4061 * Return the object/offset from this entry. If the entry was 4062 * copy-on-write or empty, it has been fixed up. 4063 */ 4064 *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); 4065 *object = entry->object.vm_object; 4066 4067 *out_prot = prot; 4068 return (KERN_SUCCESS); 4069 } 4070 4071 /* 4072 * vm_map_lookup_locked: 4073 * 4074 * Lookup the faulting address. A version of vm_map_lookup that returns 4075 * KERN_FAILURE instead of blocking on map lock or memory allocation. 4076 */ 4077 int 4078 vm_map_lookup_locked(vm_map_t *var_map, /* IN/OUT */ 4079 vm_offset_t vaddr, 4080 vm_prot_t fault_typea, 4081 vm_map_entry_t *out_entry, /* OUT */ 4082 vm_object_t *object, /* OUT */ 4083 vm_pindex_t *pindex, /* OUT */ 4084 vm_prot_t *out_prot, /* OUT */ 4085 boolean_t *wired) /* OUT */ 4086 { 4087 vm_map_entry_t entry; 4088 vm_map_t map = *var_map; 4089 vm_prot_t prot; 4090 vm_prot_t fault_type = fault_typea; 4091 4092 /* 4093 * Lookup the faulting address. 4094 */ 4095 if (!vm_map_lookup_entry(map, vaddr, out_entry)) 4096 return (KERN_INVALID_ADDRESS); 4097 4098 entry = *out_entry; 4099 4100 /* 4101 * Fail if the entry refers to a submap. 4102 */ 4103 if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) 4104 return (KERN_FAILURE); 4105 4106 /* 4107 * Check whether this task is allowed to have this page. 4108 */ 4109 prot = entry->protection; 4110 fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE; 4111 if ((fault_type & prot) != fault_type) 4112 return (KERN_PROTECTION_FAILURE); 4113 if ((entry->eflags & MAP_ENTRY_USER_WIRED) && 4114 (entry->eflags & MAP_ENTRY_COW) && 4115 (fault_type & VM_PROT_WRITE)) 4116 return (KERN_PROTECTION_FAILURE); 4117 4118 /* 4119 * If this page is not pageable, we have to get it for all possible 4120 * accesses. 4121 */ 4122 *wired = (entry->wired_count != 0); 4123 if (*wired) 4124 fault_type = entry->protection; 4125 4126 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 4127 /* 4128 * Fail if the entry was copy-on-write for a write fault. 4129 */ 4130 if (fault_type & VM_PROT_WRITE) 4131 return (KERN_FAILURE); 4132 /* 4133 * We're attempting to read a copy-on-write page -- 4134 * don't allow writes. 4135 */ 4136 prot &= ~VM_PROT_WRITE; 4137 } 4138 4139 /* 4140 * Fail if an object should be created. 4141 */ 4142 if (entry->object.vm_object == NULL && !map->system_map) 4143 return (KERN_FAILURE); 4144 4145 /* 4146 * Return the object/offset from this entry. If the entry was 4147 * copy-on-write or empty, it has been fixed up. 4148 */ 4149 *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); 4150 *object = entry->object.vm_object; 4151 4152 *out_prot = prot; 4153 return (KERN_SUCCESS); 4154 } 4155 4156 /* 4157 * vm_map_lookup_done: 4158 * 4159 * Releases locks acquired by a vm_map_lookup 4160 * (according to the handle returned by that lookup). 4161 */ 4162 void 4163 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry) 4164 { 4165 /* 4166 * Unlock the main-level map 4167 */ 4168 vm_map_unlock_read(map); 4169 } 4170 4171 #include "opt_ddb.h" 4172 #ifdef DDB 4173 #include <sys/kernel.h> 4174 4175 #include <ddb/ddb.h> 4176 4177 static void 4178 vm_map_print(vm_map_t map) 4179 { 4180 vm_map_entry_t entry; 4181 4182 db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", 4183 (void *)map, 4184 (void *)map->pmap, map->nentries, map->timestamp); 4185 4186 db_indent += 2; 4187 for (entry = map->header.next; entry != &map->header; 4188 entry = entry->next) { 4189 db_iprintf("map entry %p: start=%p, end=%p\n", 4190 (void *)entry, (void *)entry->start, (void *)entry->end); 4191 { 4192 static char *inheritance_name[4] = 4193 {"share", "copy", "none", "donate_copy"}; 4194 4195 db_iprintf(" prot=%x/%x/%s", 4196 entry->protection, 4197 entry->max_protection, 4198 inheritance_name[(int)(unsigned char)entry->inheritance]); 4199 if (entry->wired_count != 0) 4200 db_printf(", wired"); 4201 } 4202 if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 4203 db_printf(", share=%p, offset=0x%jx\n", 4204 (void *)entry->object.sub_map, 4205 (uintmax_t)entry->offset); 4206 if ((entry->prev == &map->header) || 4207 (entry->prev->object.sub_map != 4208 entry->object.sub_map)) { 4209 db_indent += 2; 4210 vm_map_print((vm_map_t)entry->object.sub_map); 4211 db_indent -= 2; 4212 } 4213 } else { 4214 if (entry->cred != NULL) 4215 db_printf(", ruid %d", entry->cred->cr_ruid); 4216 db_printf(", object=%p, offset=0x%jx", 4217 (void *)entry->object.vm_object, 4218 (uintmax_t)entry->offset); 4219 if (entry->object.vm_object && entry->object.vm_object->cred) 4220 db_printf(", obj ruid %d charge %jx", 4221 entry->object.vm_object->cred->cr_ruid, 4222 (uintmax_t)entry->object.vm_object->charge); 4223 if (entry->eflags & MAP_ENTRY_COW) 4224 db_printf(", copy (%s)", 4225 (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); 4226 db_printf("\n"); 4227 4228 if ((entry->prev == &map->header) || 4229 (entry->prev->object.vm_object != 4230 entry->object.vm_object)) { 4231 db_indent += 2; 4232 vm_object_print((db_expr_t)(intptr_t) 4233 entry->object.vm_object, 4234 0, 0, (char *)0); 4235 db_indent -= 2; 4236 } 4237 } 4238 } 4239 db_indent -= 2; 4240 } 4241 4242 DB_SHOW_COMMAND(map, map) 4243 { 4244 4245 if (!have_addr) { 4246 db_printf("usage: show map <addr>\n"); 4247 return; 4248 } 4249 vm_map_print((vm_map_t)addr); 4250 } 4251 4252 DB_SHOW_COMMAND(procvm, procvm) 4253 { 4254 struct proc *p; 4255 4256 if (have_addr) { 4257 p = (struct proc *) addr; 4258 } else { 4259 p = curproc; 4260 } 4261 4262 db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", 4263 (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, 4264 (void *)vmspace_pmap(p->p_vmspace)); 4265 4266 vm_map_print((vm_map_t)&p->p_vmspace->vm_map); 4267 } 4268 4269 #endif /* DDB */ 4270