1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_map.c 8.3 (Berkeley) 1/12/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * Virtual memory mapping module. 65 */ 66 67 #include <sys/cdefs.h> 68 __FBSDID("$FreeBSD$"); 69 70 #include <sys/param.h> 71 #include <sys/systm.h> 72 #include <sys/elf.h> 73 #include <sys/kernel.h> 74 #include <sys/ktr.h> 75 #include <sys/lock.h> 76 #include <sys/mutex.h> 77 #include <sys/proc.h> 78 #include <sys/vmmeter.h> 79 #include <sys/mman.h> 80 #include <sys/vnode.h> 81 #include <sys/racct.h> 82 #include <sys/resourcevar.h> 83 #include <sys/rwlock.h> 84 #include <sys/file.h> 85 #include <sys/sysctl.h> 86 #include <sys/sysent.h> 87 #include <sys/shm.h> 88 89 #include <vm/vm.h> 90 #include <vm/vm_param.h> 91 #include <vm/pmap.h> 92 #include <vm/vm_map.h> 93 #include <vm/vm_page.h> 94 #include <vm/vm_pageout.h> 95 #include <vm/vm_object.h> 96 #include <vm/vm_pager.h> 97 #include <vm/vm_kern.h> 98 #include <vm/vm_extern.h> 99 #include <vm/vnode_pager.h> 100 #include <vm/swap_pager.h> 101 #include <vm/uma.h> 102 103 /* 104 * Virtual memory maps provide for the mapping, protection, 105 * and sharing of virtual memory objects. In addition, 106 * this module provides for an efficient virtual copy of 107 * memory from one map to another. 108 * 109 * Synchronization is required prior to most operations. 110 * 111 * Maps consist of an ordered doubly-linked list of simple 112 * entries; a self-adjusting binary search tree of these 113 * entries is used to speed up lookups. 114 * 115 * Since portions of maps are specified by start/end addresses, 116 * which may not align with existing map entries, all 117 * routines merely "clip" entries to these start/end values. 118 * [That is, an entry is split into two, bordering at a 119 * start or end value.] Note that these clippings may not 120 * always be necessary (as the two resulting entries are then 121 * not changed); however, the clipping is done for convenience. 122 * 123 * As mentioned above, virtual copy operations are performed 124 * by copying VM object references from one map to 125 * another, and then marking both regions as copy-on-write. 126 */ 127 128 static struct mtx map_sleep_mtx; 129 static uma_zone_t mapentzone; 130 static uma_zone_t kmapentzone; 131 static uma_zone_t vmspace_zone; 132 static int vmspace_zinit(void *mem, int size, int flags); 133 static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, 134 vm_offset_t max); 135 static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map); 136 static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry); 137 static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry); 138 static int vm_map_growstack(vm_map_t map, vm_offset_t addr, 139 vm_map_entry_t gap_entry); 140 static void vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot, 141 vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags); 142 #ifdef INVARIANTS 143 static void vmspace_zdtor(void *mem, int size, void *arg); 144 #endif 145 static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, 146 vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max, 147 int cow); 148 static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, 149 vm_offset_t failed_addr); 150 151 #define ENTRY_CHARGED(e) ((e)->cred != NULL || \ 152 ((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \ 153 !((e)->eflags & MAP_ENTRY_NEEDS_COPY))) 154 155 /* 156 * PROC_VMSPACE_{UN,}LOCK() can be a noop as long as vmspaces are type 157 * stable. 158 */ 159 #define PROC_VMSPACE_LOCK(p) do { } while (0) 160 #define PROC_VMSPACE_UNLOCK(p) do { } while (0) 161 162 /* 163 * VM_MAP_RANGE_CHECK: [ internal use only ] 164 * 165 * Asserts that the starting and ending region 166 * addresses fall within the valid range of the map. 167 */ 168 #define VM_MAP_RANGE_CHECK(map, start, end) \ 169 { \ 170 if (start < vm_map_min(map)) \ 171 start = vm_map_min(map); \ 172 if (end > vm_map_max(map)) \ 173 end = vm_map_max(map); \ 174 if (start > end) \ 175 start = end; \ 176 } 177 178 #ifndef UMA_MD_SMALL_ALLOC 179 180 /* 181 * Allocate a new slab for kernel map entries. The kernel map may be locked or 182 * unlocked, depending on whether the request is coming from the kernel map or a 183 * submap. This function allocates a virtual address range directly from the 184 * kernel map instead of the kmem_* layer to avoid recursion on the kernel map 185 * lock and also to avoid triggering allocator recursion in the vmem boundary 186 * tag allocator. 187 */ 188 static void * 189 kmapent_alloc(uma_zone_t zone, vm_size_t bytes, int domain, uint8_t *pflag, 190 int wait) 191 { 192 vm_offset_t addr; 193 int error, locked; 194 195 *pflag = UMA_SLAB_PRIV; 196 197 if (!(locked = vm_map_locked(kernel_map))) 198 vm_map_lock(kernel_map); 199 addr = vm_map_findspace(kernel_map, vm_map_min(kernel_map), bytes); 200 if (addr + bytes < addr || addr + bytes > vm_map_max(kernel_map)) 201 panic("%s: kernel map is exhausted", __func__); 202 error = vm_map_insert(kernel_map, NULL, 0, addr, addr + bytes, 203 VM_PROT_RW, VM_PROT_RW, MAP_NOFAULT); 204 if (error != KERN_SUCCESS) 205 panic("%s: vm_map_insert() failed: %d", __func__, error); 206 if (!locked) 207 vm_map_unlock(kernel_map); 208 error = kmem_back_domain(domain, kernel_object, addr, bytes, M_NOWAIT | 209 M_USE_RESERVE | (wait & M_ZERO)); 210 if (error == KERN_SUCCESS) { 211 return ((void *)addr); 212 } else { 213 if (!locked) 214 vm_map_lock(kernel_map); 215 vm_map_delete(kernel_map, addr, bytes); 216 if (!locked) 217 vm_map_unlock(kernel_map); 218 return (NULL); 219 } 220 } 221 222 static void 223 kmapent_free(void *item, vm_size_t size, uint8_t pflag) 224 { 225 vm_offset_t addr; 226 int error __diagused; 227 228 if ((pflag & UMA_SLAB_PRIV) == 0) 229 /* XXX leaked */ 230 return; 231 232 addr = (vm_offset_t)item; 233 kmem_unback(kernel_object, addr, size); 234 error = vm_map_remove(kernel_map, addr, addr + size); 235 KASSERT(error == KERN_SUCCESS, 236 ("%s: vm_map_remove failed: %d", __func__, error)); 237 } 238 239 /* 240 * The worst-case upper bound on the number of kernel map entries that may be 241 * created before the zone must be replenished in _vm_map_unlock(). 242 */ 243 #define KMAPENT_RESERVE 1 244 245 #endif /* !UMD_MD_SMALL_ALLOC */ 246 247 /* 248 * vm_map_startup: 249 * 250 * Initialize the vm_map module. Must be called before any other vm_map 251 * routines. 252 * 253 * User map and entry structures are allocated from the general purpose 254 * memory pool. Kernel maps are statically defined. Kernel map entries 255 * require special handling to avoid recursion; see the comments above 256 * kmapent_alloc() and in vm_map_entry_create(). 257 */ 258 void 259 vm_map_startup(void) 260 { 261 mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF); 262 263 /* 264 * Disable the use of per-CPU buckets: map entry allocation is 265 * serialized by the kernel map lock. 266 */ 267 kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry), 268 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 269 UMA_ZONE_VM | UMA_ZONE_NOBUCKET); 270 #ifndef UMA_MD_SMALL_ALLOC 271 /* Reserve an extra map entry for use when replenishing the reserve. */ 272 uma_zone_reserve(kmapentzone, KMAPENT_RESERVE + 1); 273 uma_prealloc(kmapentzone, KMAPENT_RESERVE + 1); 274 uma_zone_set_allocf(kmapentzone, kmapent_alloc); 275 uma_zone_set_freef(kmapentzone, kmapent_free); 276 #endif 277 278 mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry), 279 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 280 vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL, 281 #ifdef INVARIANTS 282 vmspace_zdtor, 283 #else 284 NULL, 285 #endif 286 vmspace_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 287 } 288 289 static int 290 vmspace_zinit(void *mem, int size, int flags) 291 { 292 struct vmspace *vm; 293 vm_map_t map; 294 295 vm = (struct vmspace *)mem; 296 map = &vm->vm_map; 297 298 memset(map, 0, sizeof(*map)); 299 mtx_init(&map->system_mtx, "vm map (system)", NULL, 300 MTX_DEF | MTX_DUPOK); 301 sx_init(&map->lock, "vm map (user)"); 302 PMAP_LOCK_INIT(vmspace_pmap(vm)); 303 return (0); 304 } 305 306 #ifdef INVARIANTS 307 static void 308 vmspace_zdtor(void *mem, int size, void *arg) 309 { 310 struct vmspace *vm; 311 312 vm = (struct vmspace *)mem; 313 KASSERT(vm->vm_map.nentries == 0, 314 ("vmspace %p nentries == %d on free", vm, vm->vm_map.nentries)); 315 KASSERT(vm->vm_map.size == 0, 316 ("vmspace %p size == %ju on free", vm, (uintmax_t)vm->vm_map.size)); 317 } 318 #endif /* INVARIANTS */ 319 320 /* 321 * Allocate a vmspace structure, including a vm_map and pmap, 322 * and initialize those structures. The refcnt is set to 1. 323 */ 324 struct vmspace * 325 vmspace_alloc(vm_offset_t min, vm_offset_t max, pmap_pinit_t pinit) 326 { 327 struct vmspace *vm; 328 329 vm = uma_zalloc(vmspace_zone, M_WAITOK); 330 KASSERT(vm->vm_map.pmap == NULL, ("vm_map.pmap must be NULL")); 331 if (!pinit(vmspace_pmap(vm))) { 332 uma_zfree(vmspace_zone, vm); 333 return (NULL); 334 } 335 CTR1(KTR_VM, "vmspace_alloc: %p", vm); 336 _vm_map_init(&vm->vm_map, vmspace_pmap(vm), min, max); 337 refcount_init(&vm->vm_refcnt, 1); 338 vm->vm_shm = NULL; 339 vm->vm_swrss = 0; 340 vm->vm_tsize = 0; 341 vm->vm_dsize = 0; 342 vm->vm_ssize = 0; 343 vm->vm_taddr = 0; 344 vm->vm_daddr = 0; 345 vm->vm_maxsaddr = 0; 346 return (vm); 347 } 348 349 #ifdef RACCT 350 static void 351 vmspace_container_reset(struct proc *p) 352 { 353 354 PROC_LOCK(p); 355 racct_set(p, RACCT_DATA, 0); 356 racct_set(p, RACCT_STACK, 0); 357 racct_set(p, RACCT_RSS, 0); 358 racct_set(p, RACCT_MEMLOCK, 0); 359 racct_set(p, RACCT_VMEM, 0); 360 PROC_UNLOCK(p); 361 } 362 #endif 363 364 static inline void 365 vmspace_dofree(struct vmspace *vm) 366 { 367 368 CTR1(KTR_VM, "vmspace_free: %p", vm); 369 370 /* 371 * Make sure any SysV shm is freed, it might not have been in 372 * exit1(). 373 */ 374 shmexit(vm); 375 376 /* 377 * Lock the map, to wait out all other references to it. 378 * Delete all of the mappings and pages they hold, then call 379 * the pmap module to reclaim anything left. 380 */ 381 (void)vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map), 382 vm_map_max(&vm->vm_map)); 383 384 pmap_release(vmspace_pmap(vm)); 385 vm->vm_map.pmap = NULL; 386 uma_zfree(vmspace_zone, vm); 387 } 388 389 void 390 vmspace_free(struct vmspace *vm) 391 { 392 393 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 394 "vmspace_free() called"); 395 396 if (refcount_release(&vm->vm_refcnt)) 397 vmspace_dofree(vm); 398 } 399 400 void 401 vmspace_exitfree(struct proc *p) 402 { 403 struct vmspace *vm; 404 405 PROC_VMSPACE_LOCK(p); 406 vm = p->p_vmspace; 407 p->p_vmspace = NULL; 408 PROC_VMSPACE_UNLOCK(p); 409 KASSERT(vm == &vmspace0, ("vmspace_exitfree: wrong vmspace")); 410 vmspace_free(vm); 411 } 412 413 void 414 vmspace_exit(struct thread *td) 415 { 416 struct vmspace *vm; 417 struct proc *p; 418 bool released; 419 420 p = td->td_proc; 421 vm = p->p_vmspace; 422 423 /* 424 * Prepare to release the vmspace reference. The thread that releases 425 * the last reference is responsible for tearing down the vmspace. 426 * However, threads not releasing the final reference must switch to the 427 * kernel's vmspace0 before the decrement so that the subsequent pmap 428 * deactivation does not modify a freed vmspace. 429 */ 430 refcount_acquire(&vmspace0.vm_refcnt); 431 if (!(released = refcount_release_if_last(&vm->vm_refcnt))) { 432 if (p->p_vmspace != &vmspace0) { 433 PROC_VMSPACE_LOCK(p); 434 p->p_vmspace = &vmspace0; 435 PROC_VMSPACE_UNLOCK(p); 436 pmap_activate(td); 437 } 438 released = refcount_release(&vm->vm_refcnt); 439 } 440 if (released) { 441 /* 442 * pmap_remove_pages() expects the pmap to be active, so switch 443 * back first if necessary. 444 */ 445 if (p->p_vmspace != vm) { 446 PROC_VMSPACE_LOCK(p); 447 p->p_vmspace = vm; 448 PROC_VMSPACE_UNLOCK(p); 449 pmap_activate(td); 450 } 451 pmap_remove_pages(vmspace_pmap(vm)); 452 PROC_VMSPACE_LOCK(p); 453 p->p_vmspace = &vmspace0; 454 PROC_VMSPACE_UNLOCK(p); 455 pmap_activate(td); 456 vmspace_dofree(vm); 457 } 458 #ifdef RACCT 459 if (racct_enable) 460 vmspace_container_reset(p); 461 #endif 462 } 463 464 /* Acquire reference to vmspace owned by another process. */ 465 466 struct vmspace * 467 vmspace_acquire_ref(struct proc *p) 468 { 469 struct vmspace *vm; 470 471 PROC_VMSPACE_LOCK(p); 472 vm = p->p_vmspace; 473 if (vm == NULL || !refcount_acquire_if_not_zero(&vm->vm_refcnt)) { 474 PROC_VMSPACE_UNLOCK(p); 475 return (NULL); 476 } 477 if (vm != p->p_vmspace) { 478 PROC_VMSPACE_UNLOCK(p); 479 vmspace_free(vm); 480 return (NULL); 481 } 482 PROC_VMSPACE_UNLOCK(p); 483 return (vm); 484 } 485 486 /* 487 * Switch between vmspaces in an AIO kernel process. 488 * 489 * The new vmspace is either the vmspace of a user process obtained 490 * from an active AIO request or the initial vmspace of the AIO kernel 491 * process (when it is idling). Because user processes will block to 492 * drain any active AIO requests before proceeding in exit() or 493 * execve(), the reference count for vmspaces from AIO requests can 494 * never be 0. Similarly, AIO kernel processes hold an extra 495 * reference on their initial vmspace for the life of the process. As 496 * a result, the 'newvm' vmspace always has a non-zero reference 497 * count. This permits an additional reference on 'newvm' to be 498 * acquired via a simple atomic increment rather than the loop in 499 * vmspace_acquire_ref() above. 500 */ 501 void 502 vmspace_switch_aio(struct vmspace *newvm) 503 { 504 struct vmspace *oldvm; 505 506 /* XXX: Need some way to assert that this is an aio daemon. */ 507 508 KASSERT(refcount_load(&newvm->vm_refcnt) > 0, 509 ("vmspace_switch_aio: newvm unreferenced")); 510 511 oldvm = curproc->p_vmspace; 512 if (oldvm == newvm) 513 return; 514 515 /* 516 * Point to the new address space and refer to it. 517 */ 518 curproc->p_vmspace = newvm; 519 refcount_acquire(&newvm->vm_refcnt); 520 521 /* Activate the new mapping. */ 522 pmap_activate(curthread); 523 524 vmspace_free(oldvm); 525 } 526 527 void 528 _vm_map_lock(vm_map_t map, const char *file, int line) 529 { 530 531 if (map->system_map) 532 mtx_lock_flags_(&map->system_mtx, 0, file, line); 533 else 534 sx_xlock_(&map->lock, file, line); 535 map->timestamp++; 536 } 537 538 void 539 vm_map_entry_set_vnode_text(vm_map_entry_t entry, bool add) 540 { 541 vm_object_t object; 542 struct vnode *vp; 543 bool vp_held; 544 545 if ((entry->eflags & MAP_ENTRY_VN_EXEC) == 0) 546 return; 547 KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, 548 ("Submap with execs")); 549 object = entry->object.vm_object; 550 KASSERT(object != NULL, ("No object for text, entry %p", entry)); 551 if ((object->flags & OBJ_ANON) != 0) 552 object = object->handle; 553 else 554 KASSERT(object->backing_object == NULL, 555 ("non-anon object %p shadows", object)); 556 KASSERT(object != NULL, ("No content object for text, entry %p obj %p", 557 entry, entry->object.vm_object)); 558 559 /* 560 * Mostly, we do not lock the backing object. It is 561 * referenced by the entry we are processing, so it cannot go 562 * away. 563 */ 564 vm_pager_getvp(object, &vp, &vp_held); 565 if (vp != NULL) { 566 if (add) { 567 VOP_SET_TEXT_CHECKED(vp); 568 } else { 569 vn_lock(vp, LK_SHARED | LK_RETRY); 570 VOP_UNSET_TEXT_CHECKED(vp); 571 VOP_UNLOCK(vp); 572 } 573 if (vp_held) 574 vdrop(vp); 575 } 576 } 577 578 /* 579 * Use a different name for this vm_map_entry field when it's use 580 * is not consistent with its use as part of an ordered search tree. 581 */ 582 #define defer_next right 583 584 static void 585 vm_map_process_deferred(void) 586 { 587 struct thread *td; 588 vm_map_entry_t entry, next; 589 vm_object_t object; 590 591 td = curthread; 592 entry = td->td_map_def_user; 593 td->td_map_def_user = NULL; 594 while (entry != NULL) { 595 next = entry->defer_next; 596 MPASS((entry->eflags & (MAP_ENTRY_WRITECNT | 597 MAP_ENTRY_VN_EXEC)) != (MAP_ENTRY_WRITECNT | 598 MAP_ENTRY_VN_EXEC)); 599 if ((entry->eflags & MAP_ENTRY_WRITECNT) != 0) { 600 /* 601 * Decrement the object's writemappings and 602 * possibly the vnode's v_writecount. 603 */ 604 KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, 605 ("Submap with writecount")); 606 object = entry->object.vm_object; 607 KASSERT(object != NULL, ("No object for writecount")); 608 vm_pager_release_writecount(object, entry->start, 609 entry->end); 610 } 611 vm_map_entry_set_vnode_text(entry, false); 612 vm_map_entry_deallocate(entry, FALSE); 613 entry = next; 614 } 615 } 616 617 #ifdef INVARIANTS 618 static void 619 _vm_map_assert_locked(vm_map_t map, const char *file, int line) 620 { 621 622 if (map->system_map) 623 mtx_assert_(&map->system_mtx, MA_OWNED, file, line); 624 else 625 sx_assert_(&map->lock, SA_XLOCKED, file, line); 626 } 627 628 #define VM_MAP_ASSERT_LOCKED(map) \ 629 _vm_map_assert_locked(map, LOCK_FILE, LOCK_LINE) 630 631 enum { VMMAP_CHECK_NONE, VMMAP_CHECK_UNLOCK, VMMAP_CHECK_ALL }; 632 #ifdef DIAGNOSTIC 633 static int enable_vmmap_check = VMMAP_CHECK_UNLOCK; 634 #else 635 static int enable_vmmap_check = VMMAP_CHECK_NONE; 636 #endif 637 SYSCTL_INT(_debug, OID_AUTO, vmmap_check, CTLFLAG_RWTUN, 638 &enable_vmmap_check, 0, "Enable vm map consistency checking"); 639 640 static void _vm_map_assert_consistent(vm_map_t map, int check); 641 642 #define VM_MAP_ASSERT_CONSISTENT(map) \ 643 _vm_map_assert_consistent(map, VMMAP_CHECK_ALL) 644 #ifdef DIAGNOSTIC 645 #define VM_MAP_UNLOCK_CONSISTENT(map) do { \ 646 if (map->nupdates > map->nentries) { \ 647 _vm_map_assert_consistent(map, VMMAP_CHECK_UNLOCK); \ 648 map->nupdates = 0; \ 649 } \ 650 } while (0) 651 #else 652 #define VM_MAP_UNLOCK_CONSISTENT(map) 653 #endif 654 #else 655 #define VM_MAP_ASSERT_LOCKED(map) 656 #define VM_MAP_ASSERT_CONSISTENT(map) 657 #define VM_MAP_UNLOCK_CONSISTENT(map) 658 #endif /* INVARIANTS */ 659 660 void 661 _vm_map_unlock(vm_map_t map, const char *file, int line) 662 { 663 664 VM_MAP_UNLOCK_CONSISTENT(map); 665 if (map->system_map) { 666 #ifndef UMA_MD_SMALL_ALLOC 667 if (map == kernel_map && (map->flags & MAP_REPLENISH) != 0) { 668 uma_prealloc(kmapentzone, 1); 669 map->flags &= ~MAP_REPLENISH; 670 } 671 #endif 672 mtx_unlock_flags_(&map->system_mtx, 0, file, line); 673 } else { 674 sx_xunlock_(&map->lock, file, line); 675 vm_map_process_deferred(); 676 } 677 } 678 679 void 680 _vm_map_lock_read(vm_map_t map, const char *file, int line) 681 { 682 683 if (map->system_map) 684 mtx_lock_flags_(&map->system_mtx, 0, file, line); 685 else 686 sx_slock_(&map->lock, file, line); 687 } 688 689 void 690 _vm_map_unlock_read(vm_map_t map, const char *file, int line) 691 { 692 693 if (map->system_map) { 694 KASSERT((map->flags & MAP_REPLENISH) == 0, 695 ("%s: MAP_REPLENISH leaked", __func__)); 696 mtx_unlock_flags_(&map->system_mtx, 0, file, line); 697 } else { 698 sx_sunlock_(&map->lock, file, line); 699 vm_map_process_deferred(); 700 } 701 } 702 703 int 704 _vm_map_trylock(vm_map_t map, const char *file, int line) 705 { 706 int error; 707 708 error = map->system_map ? 709 !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : 710 !sx_try_xlock_(&map->lock, file, line); 711 if (error == 0) 712 map->timestamp++; 713 return (error == 0); 714 } 715 716 int 717 _vm_map_trylock_read(vm_map_t map, const char *file, int line) 718 { 719 int error; 720 721 error = map->system_map ? 722 !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : 723 !sx_try_slock_(&map->lock, file, line); 724 return (error == 0); 725 } 726 727 /* 728 * _vm_map_lock_upgrade: [ internal use only ] 729 * 730 * Tries to upgrade a read (shared) lock on the specified map to a write 731 * (exclusive) lock. Returns the value "0" if the upgrade succeeds and a 732 * non-zero value if the upgrade fails. If the upgrade fails, the map is 733 * returned without a read or write lock held. 734 * 735 * Requires that the map be read locked. 736 */ 737 int 738 _vm_map_lock_upgrade(vm_map_t map, const char *file, int line) 739 { 740 unsigned int last_timestamp; 741 742 if (map->system_map) { 743 mtx_assert_(&map->system_mtx, MA_OWNED, file, line); 744 } else { 745 if (!sx_try_upgrade_(&map->lock, file, line)) { 746 last_timestamp = map->timestamp; 747 sx_sunlock_(&map->lock, file, line); 748 vm_map_process_deferred(); 749 /* 750 * If the map's timestamp does not change while the 751 * map is unlocked, then the upgrade succeeds. 752 */ 753 sx_xlock_(&map->lock, file, line); 754 if (last_timestamp != map->timestamp) { 755 sx_xunlock_(&map->lock, file, line); 756 return (1); 757 } 758 } 759 } 760 map->timestamp++; 761 return (0); 762 } 763 764 void 765 _vm_map_lock_downgrade(vm_map_t map, const char *file, int line) 766 { 767 768 if (map->system_map) { 769 KASSERT((map->flags & MAP_REPLENISH) == 0, 770 ("%s: MAP_REPLENISH leaked", __func__)); 771 mtx_assert_(&map->system_mtx, MA_OWNED, file, line); 772 } else { 773 VM_MAP_UNLOCK_CONSISTENT(map); 774 sx_downgrade_(&map->lock, file, line); 775 } 776 } 777 778 /* 779 * vm_map_locked: 780 * 781 * Returns a non-zero value if the caller holds a write (exclusive) lock 782 * on the specified map and the value "0" otherwise. 783 */ 784 int 785 vm_map_locked(vm_map_t map) 786 { 787 788 if (map->system_map) 789 return (mtx_owned(&map->system_mtx)); 790 else 791 return (sx_xlocked(&map->lock)); 792 } 793 794 /* 795 * _vm_map_unlock_and_wait: 796 * 797 * Atomically releases the lock on the specified map and puts the calling 798 * thread to sleep. The calling thread will remain asleep until either 799 * vm_map_wakeup() is performed on the map or the specified timeout is 800 * exceeded. 801 * 802 * WARNING! This function does not perform deferred deallocations of 803 * objects and map entries. Therefore, the calling thread is expected to 804 * reacquire the map lock after reawakening and later perform an ordinary 805 * unlock operation, such as vm_map_unlock(), before completing its 806 * operation on the map. 807 */ 808 int 809 _vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line) 810 { 811 812 VM_MAP_UNLOCK_CONSISTENT(map); 813 mtx_lock(&map_sleep_mtx); 814 if (map->system_map) { 815 KASSERT((map->flags & MAP_REPLENISH) == 0, 816 ("%s: MAP_REPLENISH leaked", __func__)); 817 mtx_unlock_flags_(&map->system_mtx, 0, file, line); 818 } else { 819 sx_xunlock_(&map->lock, file, line); 820 } 821 return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", 822 timo)); 823 } 824 825 /* 826 * vm_map_wakeup: 827 * 828 * Awaken any threads that have slept on the map using 829 * vm_map_unlock_and_wait(). 830 */ 831 void 832 vm_map_wakeup(vm_map_t map) 833 { 834 835 /* 836 * Acquire and release map_sleep_mtx to prevent a wakeup() 837 * from being performed (and lost) between the map unlock 838 * and the msleep() in _vm_map_unlock_and_wait(). 839 */ 840 mtx_lock(&map_sleep_mtx); 841 mtx_unlock(&map_sleep_mtx); 842 wakeup(&map->root); 843 } 844 845 void 846 vm_map_busy(vm_map_t map) 847 { 848 849 VM_MAP_ASSERT_LOCKED(map); 850 map->busy++; 851 } 852 853 void 854 vm_map_unbusy(vm_map_t map) 855 { 856 857 VM_MAP_ASSERT_LOCKED(map); 858 KASSERT(map->busy, ("vm_map_unbusy: not busy")); 859 if (--map->busy == 0 && (map->flags & MAP_BUSY_WAKEUP)) { 860 vm_map_modflags(map, 0, MAP_BUSY_WAKEUP); 861 wakeup(&map->busy); 862 } 863 } 864 865 void 866 vm_map_wait_busy(vm_map_t map) 867 { 868 869 VM_MAP_ASSERT_LOCKED(map); 870 while (map->busy) { 871 vm_map_modflags(map, MAP_BUSY_WAKEUP, 0); 872 if (map->system_map) 873 msleep(&map->busy, &map->system_mtx, 0, "mbusy", 0); 874 else 875 sx_sleep(&map->busy, &map->lock, 0, "mbusy", 0); 876 } 877 map->timestamp++; 878 } 879 880 long 881 vmspace_resident_count(struct vmspace *vmspace) 882 { 883 return pmap_resident_count(vmspace_pmap(vmspace)); 884 } 885 886 /* 887 * Initialize an existing vm_map structure 888 * such as that in the vmspace structure. 889 */ 890 static void 891 _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) 892 { 893 894 map->header.eflags = MAP_ENTRY_HEADER; 895 map->needs_wakeup = FALSE; 896 map->system_map = 0; 897 map->pmap = pmap; 898 map->header.end = min; 899 map->header.start = max; 900 map->flags = 0; 901 map->header.left = map->header.right = &map->header; 902 map->root = NULL; 903 map->timestamp = 0; 904 map->busy = 0; 905 map->anon_loc = 0; 906 #ifdef DIAGNOSTIC 907 map->nupdates = 0; 908 #endif 909 } 910 911 void 912 vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) 913 { 914 915 _vm_map_init(map, pmap, min, max); 916 mtx_init(&map->system_mtx, "vm map (system)", NULL, 917 MTX_DEF | MTX_DUPOK); 918 sx_init(&map->lock, "vm map (user)"); 919 } 920 921 /* 922 * vm_map_entry_dispose: [ internal use only ] 923 * 924 * Inverse of vm_map_entry_create. 925 */ 926 static void 927 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry) 928 { 929 uma_zfree(map->system_map ? kmapentzone : mapentzone, entry); 930 } 931 932 /* 933 * vm_map_entry_create: [ internal use only ] 934 * 935 * Allocates a VM map entry for insertion. 936 * No entry fields are filled in. 937 */ 938 static vm_map_entry_t 939 vm_map_entry_create(vm_map_t map) 940 { 941 vm_map_entry_t new_entry; 942 943 #ifndef UMA_MD_SMALL_ALLOC 944 if (map == kernel_map) { 945 VM_MAP_ASSERT_LOCKED(map); 946 947 /* 948 * A new slab of kernel map entries cannot be allocated at this 949 * point because the kernel map has not yet been updated to 950 * reflect the caller's request. Therefore, we allocate a new 951 * map entry, dipping into the reserve if necessary, and set a 952 * flag indicating that the reserve must be replenished before 953 * the map is unlocked. 954 */ 955 new_entry = uma_zalloc(kmapentzone, M_NOWAIT | M_NOVM); 956 if (new_entry == NULL) { 957 new_entry = uma_zalloc(kmapentzone, 958 M_NOWAIT | M_NOVM | M_USE_RESERVE); 959 kernel_map->flags |= MAP_REPLENISH; 960 } 961 } else 962 #endif 963 if (map->system_map) { 964 new_entry = uma_zalloc(kmapentzone, M_NOWAIT); 965 } else { 966 new_entry = uma_zalloc(mapentzone, M_WAITOK); 967 } 968 KASSERT(new_entry != NULL, 969 ("vm_map_entry_create: kernel resources exhausted")); 970 return (new_entry); 971 } 972 973 /* 974 * vm_map_entry_set_behavior: 975 * 976 * Set the expected access behavior, either normal, random, or 977 * sequential. 978 */ 979 static inline void 980 vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior) 981 { 982 entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) | 983 (behavior & MAP_ENTRY_BEHAV_MASK); 984 } 985 986 /* 987 * vm_map_entry_max_free_{left,right}: 988 * 989 * Compute the size of the largest free gap between two entries, 990 * one the root of a tree and the other the ancestor of that root 991 * that is the least or greatest ancestor found on the search path. 992 */ 993 static inline vm_size_t 994 vm_map_entry_max_free_left(vm_map_entry_t root, vm_map_entry_t left_ancestor) 995 { 996 997 return (root->left != left_ancestor ? 998 root->left->max_free : root->start - left_ancestor->end); 999 } 1000 1001 static inline vm_size_t 1002 vm_map_entry_max_free_right(vm_map_entry_t root, vm_map_entry_t right_ancestor) 1003 { 1004 1005 return (root->right != right_ancestor ? 1006 root->right->max_free : right_ancestor->start - root->end); 1007 } 1008 1009 /* 1010 * vm_map_entry_{pred,succ}: 1011 * 1012 * Find the {predecessor, successor} of the entry by taking one step 1013 * in the appropriate direction and backtracking as much as necessary. 1014 * vm_map_entry_succ is defined in vm_map.h. 1015 */ 1016 static inline vm_map_entry_t 1017 vm_map_entry_pred(vm_map_entry_t entry) 1018 { 1019 vm_map_entry_t prior; 1020 1021 prior = entry->left; 1022 if (prior->right->start < entry->start) { 1023 do 1024 prior = prior->right; 1025 while (prior->right != entry); 1026 } 1027 return (prior); 1028 } 1029 1030 static inline vm_size_t 1031 vm_size_max(vm_size_t a, vm_size_t b) 1032 { 1033 1034 return (a > b ? a : b); 1035 } 1036 1037 #define SPLAY_LEFT_STEP(root, y, llist, rlist, test) do { \ 1038 vm_map_entry_t z; \ 1039 vm_size_t max_free; \ 1040 \ 1041 /* \ 1042 * Infer root->right->max_free == root->max_free when \ 1043 * y->max_free < root->max_free || root->max_free == 0. \ 1044 * Otherwise, look right to find it. \ 1045 */ \ 1046 y = root->left; \ 1047 max_free = root->max_free; \ 1048 KASSERT(max_free == vm_size_max( \ 1049 vm_map_entry_max_free_left(root, llist), \ 1050 vm_map_entry_max_free_right(root, rlist)), \ 1051 ("%s: max_free invariant fails", __func__)); \ 1052 if (max_free - 1 < vm_map_entry_max_free_left(root, llist)) \ 1053 max_free = vm_map_entry_max_free_right(root, rlist); \ 1054 if (y != llist && (test)) { \ 1055 /* Rotate right and make y root. */ \ 1056 z = y->right; \ 1057 if (z != root) { \ 1058 root->left = z; \ 1059 y->right = root; \ 1060 if (max_free < y->max_free) \ 1061 root->max_free = max_free = \ 1062 vm_size_max(max_free, z->max_free); \ 1063 } else if (max_free < y->max_free) \ 1064 root->max_free = max_free = \ 1065 vm_size_max(max_free, root->start - y->end);\ 1066 root = y; \ 1067 y = root->left; \ 1068 } \ 1069 /* Copy right->max_free. Put root on rlist. */ \ 1070 root->max_free = max_free; \ 1071 KASSERT(max_free == vm_map_entry_max_free_right(root, rlist), \ 1072 ("%s: max_free not copied from right", __func__)); \ 1073 root->left = rlist; \ 1074 rlist = root; \ 1075 root = y != llist ? y : NULL; \ 1076 } while (0) 1077 1078 #define SPLAY_RIGHT_STEP(root, y, llist, rlist, test) do { \ 1079 vm_map_entry_t z; \ 1080 vm_size_t max_free; \ 1081 \ 1082 /* \ 1083 * Infer root->left->max_free == root->max_free when \ 1084 * y->max_free < root->max_free || root->max_free == 0. \ 1085 * Otherwise, look left to find it. \ 1086 */ \ 1087 y = root->right; \ 1088 max_free = root->max_free; \ 1089 KASSERT(max_free == vm_size_max( \ 1090 vm_map_entry_max_free_left(root, llist), \ 1091 vm_map_entry_max_free_right(root, rlist)), \ 1092 ("%s: max_free invariant fails", __func__)); \ 1093 if (max_free - 1 < vm_map_entry_max_free_right(root, rlist)) \ 1094 max_free = vm_map_entry_max_free_left(root, llist); \ 1095 if (y != rlist && (test)) { \ 1096 /* Rotate left and make y root. */ \ 1097 z = y->left; \ 1098 if (z != root) { \ 1099 root->right = z; \ 1100 y->left = root; \ 1101 if (max_free < y->max_free) \ 1102 root->max_free = max_free = \ 1103 vm_size_max(max_free, z->max_free); \ 1104 } else if (max_free < y->max_free) \ 1105 root->max_free = max_free = \ 1106 vm_size_max(max_free, y->start - root->end);\ 1107 root = y; \ 1108 y = root->right; \ 1109 } \ 1110 /* Copy left->max_free. Put root on llist. */ \ 1111 root->max_free = max_free; \ 1112 KASSERT(max_free == vm_map_entry_max_free_left(root, llist), \ 1113 ("%s: max_free not copied from left", __func__)); \ 1114 root->right = llist; \ 1115 llist = root; \ 1116 root = y != rlist ? y : NULL; \ 1117 } while (0) 1118 1119 /* 1120 * Walk down the tree until we find addr or a gap where addr would go, breaking 1121 * off left and right subtrees of nodes less than, or greater than addr. Treat 1122 * subtrees with root->max_free < length as empty trees. llist and rlist are 1123 * the two sides in reverse order (bottom-up), with llist linked by the right 1124 * pointer and rlist linked by the left pointer in the vm_map_entry, and both 1125 * lists terminated by &map->header. This function, and the subsequent call to 1126 * vm_map_splay_merge_{left,right,pred,succ}, rely on the start and end address 1127 * values in &map->header. 1128 */ 1129 static __always_inline vm_map_entry_t 1130 vm_map_splay_split(vm_map_t map, vm_offset_t addr, vm_size_t length, 1131 vm_map_entry_t *llist, vm_map_entry_t *rlist) 1132 { 1133 vm_map_entry_t left, right, root, y; 1134 1135 left = right = &map->header; 1136 root = map->root; 1137 while (root != NULL && root->max_free >= length) { 1138 KASSERT(left->end <= root->start && 1139 root->end <= right->start, 1140 ("%s: root not within tree bounds", __func__)); 1141 if (addr < root->start) { 1142 SPLAY_LEFT_STEP(root, y, left, right, 1143 y->max_free >= length && addr < y->start); 1144 } else if (addr >= root->end) { 1145 SPLAY_RIGHT_STEP(root, y, left, right, 1146 y->max_free >= length && addr >= y->end); 1147 } else 1148 break; 1149 } 1150 *llist = left; 1151 *rlist = right; 1152 return (root); 1153 } 1154 1155 static __always_inline void 1156 vm_map_splay_findnext(vm_map_entry_t root, vm_map_entry_t *rlist) 1157 { 1158 vm_map_entry_t hi, right, y; 1159 1160 right = *rlist; 1161 hi = root->right == right ? NULL : root->right; 1162 if (hi == NULL) 1163 return; 1164 do 1165 SPLAY_LEFT_STEP(hi, y, root, right, true); 1166 while (hi != NULL); 1167 *rlist = right; 1168 } 1169 1170 static __always_inline void 1171 vm_map_splay_findprev(vm_map_entry_t root, vm_map_entry_t *llist) 1172 { 1173 vm_map_entry_t left, lo, y; 1174 1175 left = *llist; 1176 lo = root->left == left ? NULL : root->left; 1177 if (lo == NULL) 1178 return; 1179 do 1180 SPLAY_RIGHT_STEP(lo, y, left, root, true); 1181 while (lo != NULL); 1182 *llist = left; 1183 } 1184 1185 static inline void 1186 vm_map_entry_swap(vm_map_entry_t *a, vm_map_entry_t *b) 1187 { 1188 vm_map_entry_t tmp; 1189 1190 tmp = *b; 1191 *b = *a; 1192 *a = tmp; 1193 } 1194 1195 /* 1196 * Walk back up the two spines, flip the pointers and set max_free. The 1197 * subtrees of the root go at the bottom of llist and rlist. 1198 */ 1199 static vm_size_t 1200 vm_map_splay_merge_left_walk(vm_map_entry_t header, vm_map_entry_t root, 1201 vm_map_entry_t tail, vm_size_t max_free, vm_map_entry_t llist) 1202 { 1203 do { 1204 /* 1205 * The max_free values of the children of llist are in 1206 * llist->max_free and max_free. Update with the 1207 * max value. 1208 */ 1209 llist->max_free = max_free = 1210 vm_size_max(llist->max_free, max_free); 1211 vm_map_entry_swap(&llist->right, &tail); 1212 vm_map_entry_swap(&tail, &llist); 1213 } while (llist != header); 1214 root->left = tail; 1215 return (max_free); 1216 } 1217 1218 /* 1219 * When llist is known to be the predecessor of root. 1220 */ 1221 static inline vm_size_t 1222 vm_map_splay_merge_pred(vm_map_entry_t header, vm_map_entry_t root, 1223 vm_map_entry_t llist) 1224 { 1225 vm_size_t max_free; 1226 1227 max_free = root->start - llist->end; 1228 if (llist != header) { 1229 max_free = vm_map_splay_merge_left_walk(header, root, 1230 root, max_free, llist); 1231 } else { 1232 root->left = header; 1233 header->right = root; 1234 } 1235 return (max_free); 1236 } 1237 1238 /* 1239 * When llist may or may not be the predecessor of root. 1240 */ 1241 static inline vm_size_t 1242 vm_map_splay_merge_left(vm_map_entry_t header, vm_map_entry_t root, 1243 vm_map_entry_t llist) 1244 { 1245 vm_size_t max_free; 1246 1247 max_free = vm_map_entry_max_free_left(root, llist); 1248 if (llist != header) { 1249 max_free = vm_map_splay_merge_left_walk(header, root, 1250 root->left == llist ? root : root->left, 1251 max_free, llist); 1252 } 1253 return (max_free); 1254 } 1255 1256 static vm_size_t 1257 vm_map_splay_merge_right_walk(vm_map_entry_t header, vm_map_entry_t root, 1258 vm_map_entry_t tail, vm_size_t max_free, vm_map_entry_t rlist) 1259 { 1260 do { 1261 /* 1262 * The max_free values of the children of rlist are in 1263 * rlist->max_free and max_free. Update with the 1264 * max value. 1265 */ 1266 rlist->max_free = max_free = 1267 vm_size_max(rlist->max_free, max_free); 1268 vm_map_entry_swap(&rlist->left, &tail); 1269 vm_map_entry_swap(&tail, &rlist); 1270 } while (rlist != header); 1271 root->right = tail; 1272 return (max_free); 1273 } 1274 1275 /* 1276 * When rlist is known to be the succecessor of root. 1277 */ 1278 static inline vm_size_t 1279 vm_map_splay_merge_succ(vm_map_entry_t header, vm_map_entry_t root, 1280 vm_map_entry_t rlist) 1281 { 1282 vm_size_t max_free; 1283 1284 max_free = rlist->start - root->end; 1285 if (rlist != header) { 1286 max_free = vm_map_splay_merge_right_walk(header, root, 1287 root, max_free, rlist); 1288 } else { 1289 root->right = header; 1290 header->left = root; 1291 } 1292 return (max_free); 1293 } 1294 1295 /* 1296 * When rlist may or may not be the succecessor of root. 1297 */ 1298 static inline vm_size_t 1299 vm_map_splay_merge_right(vm_map_entry_t header, vm_map_entry_t root, 1300 vm_map_entry_t rlist) 1301 { 1302 vm_size_t max_free; 1303 1304 max_free = vm_map_entry_max_free_right(root, rlist); 1305 if (rlist != header) { 1306 max_free = vm_map_splay_merge_right_walk(header, root, 1307 root->right == rlist ? root : root->right, 1308 max_free, rlist); 1309 } 1310 return (max_free); 1311 } 1312 1313 /* 1314 * vm_map_splay: 1315 * 1316 * The Sleator and Tarjan top-down splay algorithm with the 1317 * following variation. Max_free must be computed bottom-up, so 1318 * on the downward pass, maintain the left and right spines in 1319 * reverse order. Then, make a second pass up each side to fix 1320 * the pointers and compute max_free. The time bound is O(log n) 1321 * amortized. 1322 * 1323 * The tree is threaded, which means that there are no null pointers. 1324 * When a node has no left child, its left pointer points to its 1325 * predecessor, which the last ancestor on the search path from the root 1326 * where the search branched right. Likewise, when a node has no right 1327 * child, its right pointer points to its successor. The map header node 1328 * is the predecessor of the first map entry, and the successor of the 1329 * last. 1330 * 1331 * The new root is the vm_map_entry containing "addr", or else an 1332 * adjacent entry (lower if possible) if addr is not in the tree. 1333 * 1334 * The map must be locked, and leaves it so. 1335 * 1336 * Returns: the new root. 1337 */ 1338 static vm_map_entry_t 1339 vm_map_splay(vm_map_t map, vm_offset_t addr) 1340 { 1341 vm_map_entry_t header, llist, rlist, root; 1342 vm_size_t max_free_left, max_free_right; 1343 1344 header = &map->header; 1345 root = vm_map_splay_split(map, addr, 0, &llist, &rlist); 1346 if (root != NULL) { 1347 max_free_left = vm_map_splay_merge_left(header, root, llist); 1348 max_free_right = vm_map_splay_merge_right(header, root, rlist); 1349 } else if (llist != header) { 1350 /* 1351 * Recover the greatest node in the left 1352 * subtree and make it the root. 1353 */ 1354 root = llist; 1355 llist = root->right; 1356 max_free_left = vm_map_splay_merge_left(header, root, llist); 1357 max_free_right = vm_map_splay_merge_succ(header, root, rlist); 1358 } else if (rlist != header) { 1359 /* 1360 * Recover the least node in the right 1361 * subtree and make it the root. 1362 */ 1363 root = rlist; 1364 rlist = root->left; 1365 max_free_left = vm_map_splay_merge_pred(header, root, llist); 1366 max_free_right = vm_map_splay_merge_right(header, root, rlist); 1367 } else { 1368 /* There is no root. */ 1369 return (NULL); 1370 } 1371 root->max_free = vm_size_max(max_free_left, max_free_right); 1372 map->root = root; 1373 VM_MAP_ASSERT_CONSISTENT(map); 1374 return (root); 1375 } 1376 1377 /* 1378 * vm_map_entry_{un,}link: 1379 * 1380 * Insert/remove entries from maps. On linking, if new entry clips 1381 * existing entry, trim existing entry to avoid overlap, and manage 1382 * offsets. On unlinking, merge disappearing entry with neighbor, if 1383 * called for, and manage offsets. Callers should not modify fields in 1384 * entries already mapped. 1385 */ 1386 static void 1387 vm_map_entry_link(vm_map_t map, vm_map_entry_t entry) 1388 { 1389 vm_map_entry_t header, llist, rlist, root; 1390 vm_size_t max_free_left, max_free_right; 1391 1392 CTR3(KTR_VM, 1393 "vm_map_entry_link: map %p, nentries %d, entry %p", map, 1394 map->nentries, entry); 1395 VM_MAP_ASSERT_LOCKED(map); 1396 map->nentries++; 1397 header = &map->header; 1398 root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist); 1399 if (root == NULL) { 1400 /* 1401 * The new entry does not overlap any existing entry in the 1402 * map, so it becomes the new root of the map tree. 1403 */ 1404 max_free_left = vm_map_splay_merge_pred(header, entry, llist); 1405 max_free_right = vm_map_splay_merge_succ(header, entry, rlist); 1406 } else if (entry->start == root->start) { 1407 /* 1408 * The new entry is a clone of root, with only the end field 1409 * changed. The root entry will be shrunk to abut the new 1410 * entry, and will be the right child of the new root entry in 1411 * the modified map. 1412 */ 1413 KASSERT(entry->end < root->end, 1414 ("%s: clip_start not within entry", __func__)); 1415 vm_map_splay_findprev(root, &llist); 1416 root->offset += entry->end - root->start; 1417 root->start = entry->end; 1418 max_free_left = vm_map_splay_merge_pred(header, entry, llist); 1419 max_free_right = root->max_free = vm_size_max( 1420 vm_map_splay_merge_pred(entry, root, entry), 1421 vm_map_splay_merge_right(header, root, rlist)); 1422 } else { 1423 /* 1424 * The new entry is a clone of root, with only the start field 1425 * changed. The root entry will be shrunk to abut the new 1426 * entry, and will be the left child of the new root entry in 1427 * the modified map. 1428 */ 1429 KASSERT(entry->end == root->end, 1430 ("%s: clip_start not within entry", __func__)); 1431 vm_map_splay_findnext(root, &rlist); 1432 entry->offset += entry->start - root->start; 1433 root->end = entry->start; 1434 max_free_left = root->max_free = vm_size_max( 1435 vm_map_splay_merge_left(header, root, llist), 1436 vm_map_splay_merge_succ(entry, root, entry)); 1437 max_free_right = vm_map_splay_merge_succ(header, entry, rlist); 1438 } 1439 entry->max_free = vm_size_max(max_free_left, max_free_right); 1440 map->root = entry; 1441 VM_MAP_ASSERT_CONSISTENT(map); 1442 } 1443 1444 enum unlink_merge_type { 1445 UNLINK_MERGE_NONE, 1446 UNLINK_MERGE_NEXT 1447 }; 1448 1449 static void 1450 vm_map_entry_unlink(vm_map_t map, vm_map_entry_t entry, 1451 enum unlink_merge_type op) 1452 { 1453 vm_map_entry_t header, llist, rlist, root; 1454 vm_size_t max_free_left, max_free_right; 1455 1456 VM_MAP_ASSERT_LOCKED(map); 1457 header = &map->header; 1458 root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist); 1459 KASSERT(root != NULL, 1460 ("vm_map_entry_unlink: unlink object not mapped")); 1461 1462 vm_map_splay_findprev(root, &llist); 1463 vm_map_splay_findnext(root, &rlist); 1464 if (op == UNLINK_MERGE_NEXT) { 1465 rlist->start = root->start; 1466 rlist->offset = root->offset; 1467 } 1468 if (llist != header) { 1469 root = llist; 1470 llist = root->right; 1471 max_free_left = vm_map_splay_merge_left(header, root, llist); 1472 max_free_right = vm_map_splay_merge_succ(header, root, rlist); 1473 } else if (rlist != header) { 1474 root = rlist; 1475 rlist = root->left; 1476 max_free_left = vm_map_splay_merge_pred(header, root, llist); 1477 max_free_right = vm_map_splay_merge_right(header, root, rlist); 1478 } else { 1479 header->left = header->right = header; 1480 root = NULL; 1481 } 1482 if (root != NULL) 1483 root->max_free = vm_size_max(max_free_left, max_free_right); 1484 map->root = root; 1485 VM_MAP_ASSERT_CONSISTENT(map); 1486 map->nentries--; 1487 CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map, 1488 map->nentries, entry); 1489 } 1490 1491 /* 1492 * vm_map_entry_resize: 1493 * 1494 * Resize a vm_map_entry, recompute the amount of free space that 1495 * follows it and propagate that value up the tree. 1496 * 1497 * The map must be locked, and leaves it so. 1498 */ 1499 static void 1500 vm_map_entry_resize(vm_map_t map, vm_map_entry_t entry, vm_size_t grow_amount) 1501 { 1502 vm_map_entry_t header, llist, rlist, root; 1503 1504 VM_MAP_ASSERT_LOCKED(map); 1505 header = &map->header; 1506 root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist); 1507 KASSERT(root != NULL, ("%s: resize object not mapped", __func__)); 1508 vm_map_splay_findnext(root, &rlist); 1509 entry->end += grow_amount; 1510 root->max_free = vm_size_max( 1511 vm_map_splay_merge_left(header, root, llist), 1512 vm_map_splay_merge_succ(header, root, rlist)); 1513 map->root = root; 1514 VM_MAP_ASSERT_CONSISTENT(map); 1515 CTR4(KTR_VM, "%s: map %p, nentries %d, entry %p", 1516 __func__, map, map->nentries, entry); 1517 } 1518 1519 /* 1520 * vm_map_lookup_entry: [ internal use only ] 1521 * 1522 * Finds the map entry containing (or 1523 * immediately preceding) the specified address 1524 * in the given map; the entry is returned 1525 * in the "entry" parameter. The boolean 1526 * result indicates whether the address is 1527 * actually contained in the map. 1528 */ 1529 boolean_t 1530 vm_map_lookup_entry( 1531 vm_map_t map, 1532 vm_offset_t address, 1533 vm_map_entry_t *entry) /* OUT */ 1534 { 1535 vm_map_entry_t cur, header, lbound, ubound; 1536 boolean_t locked; 1537 1538 /* 1539 * If the map is empty, then the map entry immediately preceding 1540 * "address" is the map's header. 1541 */ 1542 header = &map->header; 1543 cur = map->root; 1544 if (cur == NULL) { 1545 *entry = header; 1546 return (FALSE); 1547 } 1548 if (address >= cur->start && cur->end > address) { 1549 *entry = cur; 1550 return (TRUE); 1551 } 1552 if ((locked = vm_map_locked(map)) || 1553 sx_try_upgrade(&map->lock)) { 1554 /* 1555 * Splay requires a write lock on the map. However, it only 1556 * restructures the binary search tree; it does not otherwise 1557 * change the map. Thus, the map's timestamp need not change 1558 * on a temporary upgrade. 1559 */ 1560 cur = vm_map_splay(map, address); 1561 if (!locked) { 1562 VM_MAP_UNLOCK_CONSISTENT(map); 1563 sx_downgrade(&map->lock); 1564 } 1565 1566 /* 1567 * If "address" is contained within a map entry, the new root 1568 * is that map entry. Otherwise, the new root is a map entry 1569 * immediately before or after "address". 1570 */ 1571 if (address < cur->start) { 1572 *entry = header; 1573 return (FALSE); 1574 } 1575 *entry = cur; 1576 return (address < cur->end); 1577 } 1578 /* 1579 * Since the map is only locked for read access, perform a 1580 * standard binary search tree lookup for "address". 1581 */ 1582 lbound = ubound = header; 1583 for (;;) { 1584 if (address < cur->start) { 1585 ubound = cur; 1586 cur = cur->left; 1587 if (cur == lbound) 1588 break; 1589 } else if (cur->end <= address) { 1590 lbound = cur; 1591 cur = cur->right; 1592 if (cur == ubound) 1593 break; 1594 } else { 1595 *entry = cur; 1596 return (TRUE); 1597 } 1598 } 1599 *entry = lbound; 1600 return (FALSE); 1601 } 1602 1603 /* 1604 * vm_map_insert: 1605 * 1606 * Inserts the given VM object into the target map at the 1607 * specified address range. 1608 * 1609 * Requires that the map be locked, and leaves it so. 1610 * 1611 * If object is non-NULL, ref count must be bumped by caller 1612 * prior to making call to account for the new entry. 1613 */ 1614 int 1615 vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1616 vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow) 1617 { 1618 vm_map_entry_t new_entry, next_entry, prev_entry; 1619 struct ucred *cred; 1620 vm_eflags_t protoeflags; 1621 vm_inherit_t inheritance; 1622 u_long bdry; 1623 u_int bidx; 1624 1625 VM_MAP_ASSERT_LOCKED(map); 1626 KASSERT(object != kernel_object || 1627 (cow & MAP_COPY_ON_WRITE) == 0, 1628 ("vm_map_insert: kernel object and COW")); 1629 KASSERT(object == NULL || (cow & MAP_NOFAULT) == 0 || 1630 (cow & MAP_SPLIT_BOUNDARY_MASK) != 0, 1631 ("vm_map_insert: paradoxical MAP_NOFAULT request, obj %p cow %#x", 1632 object, cow)); 1633 KASSERT((prot & ~max) == 0, 1634 ("prot %#x is not subset of max_prot %#x", prot, max)); 1635 1636 /* 1637 * Check that the start and end points are not bogus. 1638 */ 1639 if (start == end || !vm_map_range_valid(map, start, end)) 1640 return (KERN_INVALID_ADDRESS); 1641 1642 if ((map->flags & MAP_WXORX) != 0 && (prot & (VM_PROT_WRITE | 1643 VM_PROT_EXECUTE)) == (VM_PROT_WRITE | VM_PROT_EXECUTE)) 1644 return (KERN_PROTECTION_FAILURE); 1645 1646 /* 1647 * Find the entry prior to the proposed starting address; if it's part 1648 * of an existing entry, this range is bogus. 1649 */ 1650 if (vm_map_lookup_entry(map, start, &prev_entry)) 1651 return (KERN_NO_SPACE); 1652 1653 /* 1654 * Assert that the next entry doesn't overlap the end point. 1655 */ 1656 next_entry = vm_map_entry_succ(prev_entry); 1657 if (next_entry->start < end) 1658 return (KERN_NO_SPACE); 1659 1660 if ((cow & MAP_CREATE_GUARD) != 0 && (object != NULL || 1661 max != VM_PROT_NONE)) 1662 return (KERN_INVALID_ARGUMENT); 1663 1664 protoeflags = 0; 1665 if (cow & MAP_COPY_ON_WRITE) 1666 protoeflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY; 1667 if (cow & MAP_NOFAULT) 1668 protoeflags |= MAP_ENTRY_NOFAULT; 1669 if (cow & MAP_DISABLE_SYNCER) 1670 protoeflags |= MAP_ENTRY_NOSYNC; 1671 if (cow & MAP_DISABLE_COREDUMP) 1672 protoeflags |= MAP_ENTRY_NOCOREDUMP; 1673 if (cow & MAP_STACK_GROWS_DOWN) 1674 protoeflags |= MAP_ENTRY_GROWS_DOWN; 1675 if (cow & MAP_STACK_GROWS_UP) 1676 protoeflags |= MAP_ENTRY_GROWS_UP; 1677 if (cow & MAP_WRITECOUNT) 1678 protoeflags |= MAP_ENTRY_WRITECNT; 1679 if (cow & MAP_VN_EXEC) 1680 protoeflags |= MAP_ENTRY_VN_EXEC; 1681 if ((cow & MAP_CREATE_GUARD) != 0) 1682 protoeflags |= MAP_ENTRY_GUARD; 1683 if ((cow & MAP_CREATE_STACK_GAP_DN) != 0) 1684 protoeflags |= MAP_ENTRY_STACK_GAP_DN; 1685 if ((cow & MAP_CREATE_STACK_GAP_UP) != 0) 1686 protoeflags |= MAP_ENTRY_STACK_GAP_UP; 1687 if (cow & MAP_INHERIT_SHARE) 1688 inheritance = VM_INHERIT_SHARE; 1689 else 1690 inheritance = VM_INHERIT_DEFAULT; 1691 if ((cow & MAP_SPLIT_BOUNDARY_MASK) != 0) { 1692 /* This magically ignores index 0, for usual page size. */ 1693 bidx = (cow & MAP_SPLIT_BOUNDARY_MASK) >> 1694 MAP_SPLIT_BOUNDARY_SHIFT; 1695 if (bidx >= MAXPAGESIZES) 1696 return (KERN_INVALID_ARGUMENT); 1697 bdry = pagesizes[bidx] - 1; 1698 if ((start & bdry) != 0 || (end & bdry) != 0) 1699 return (KERN_INVALID_ARGUMENT); 1700 protoeflags |= bidx << MAP_ENTRY_SPLIT_BOUNDARY_SHIFT; 1701 } 1702 1703 cred = NULL; 1704 if ((cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT | MAP_CREATE_GUARD)) != 0) 1705 goto charged; 1706 if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) && 1707 ((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) { 1708 if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start)) 1709 return (KERN_RESOURCE_SHORTAGE); 1710 KASSERT(object == NULL || 1711 (protoeflags & MAP_ENTRY_NEEDS_COPY) != 0 || 1712 object->cred == NULL, 1713 ("overcommit: vm_map_insert o %p", object)); 1714 cred = curthread->td_ucred; 1715 } 1716 1717 charged: 1718 /* Expand the kernel pmap, if necessary. */ 1719 if (map == kernel_map && end > kernel_vm_end) 1720 pmap_growkernel(end); 1721 if (object != NULL) { 1722 /* 1723 * OBJ_ONEMAPPING must be cleared unless this mapping 1724 * is trivially proven to be the only mapping for any 1725 * of the object's pages. (Object granularity 1726 * reference counting is insufficient to recognize 1727 * aliases with precision.) 1728 */ 1729 if ((object->flags & OBJ_ANON) != 0) { 1730 VM_OBJECT_WLOCK(object); 1731 if (object->ref_count > 1 || object->shadow_count != 0) 1732 vm_object_clear_flag(object, OBJ_ONEMAPPING); 1733 VM_OBJECT_WUNLOCK(object); 1734 } 1735 } else if ((prev_entry->eflags & ~MAP_ENTRY_USER_WIRED) == 1736 protoeflags && 1737 (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP | 1738 MAP_VN_EXEC)) == 0 && 1739 prev_entry->end == start && (prev_entry->cred == cred || 1740 (prev_entry->object.vm_object != NULL && 1741 prev_entry->object.vm_object->cred == cred)) && 1742 vm_object_coalesce(prev_entry->object.vm_object, 1743 prev_entry->offset, 1744 (vm_size_t)(prev_entry->end - prev_entry->start), 1745 (vm_size_t)(end - prev_entry->end), cred != NULL && 1746 (protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)) { 1747 /* 1748 * We were able to extend the object. Determine if we 1749 * can extend the previous map entry to include the 1750 * new range as well. 1751 */ 1752 if (prev_entry->inheritance == inheritance && 1753 prev_entry->protection == prot && 1754 prev_entry->max_protection == max && 1755 prev_entry->wired_count == 0) { 1756 KASSERT((prev_entry->eflags & MAP_ENTRY_USER_WIRED) == 1757 0, ("prev_entry %p has incoherent wiring", 1758 prev_entry)); 1759 if ((prev_entry->eflags & MAP_ENTRY_GUARD) == 0) 1760 map->size += end - prev_entry->end; 1761 vm_map_entry_resize(map, prev_entry, 1762 end - prev_entry->end); 1763 vm_map_try_merge_entries(map, prev_entry, next_entry); 1764 return (KERN_SUCCESS); 1765 } 1766 1767 /* 1768 * If we can extend the object but cannot extend the 1769 * map entry, we have to create a new map entry. We 1770 * must bump the ref count on the extended object to 1771 * account for it. object may be NULL. 1772 */ 1773 object = prev_entry->object.vm_object; 1774 offset = prev_entry->offset + 1775 (prev_entry->end - prev_entry->start); 1776 vm_object_reference(object); 1777 if (cred != NULL && object != NULL && object->cred != NULL && 1778 !(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { 1779 /* Object already accounts for this uid. */ 1780 cred = NULL; 1781 } 1782 } 1783 if (cred != NULL) 1784 crhold(cred); 1785 1786 /* 1787 * Create a new entry 1788 */ 1789 new_entry = vm_map_entry_create(map); 1790 new_entry->start = start; 1791 new_entry->end = end; 1792 new_entry->cred = NULL; 1793 1794 new_entry->eflags = protoeflags; 1795 new_entry->object.vm_object = object; 1796 new_entry->offset = offset; 1797 1798 new_entry->inheritance = inheritance; 1799 new_entry->protection = prot; 1800 new_entry->max_protection = max; 1801 new_entry->wired_count = 0; 1802 new_entry->wiring_thread = NULL; 1803 new_entry->read_ahead = VM_FAULT_READ_AHEAD_INIT; 1804 new_entry->next_read = start; 1805 1806 KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry), 1807 ("overcommit: vm_map_insert leaks vm_map %p", new_entry)); 1808 new_entry->cred = cred; 1809 1810 /* 1811 * Insert the new entry into the list 1812 */ 1813 vm_map_entry_link(map, new_entry); 1814 if ((new_entry->eflags & MAP_ENTRY_GUARD) == 0) 1815 map->size += new_entry->end - new_entry->start; 1816 1817 /* 1818 * Try to coalesce the new entry with both the previous and next 1819 * entries in the list. Previously, we only attempted to coalesce 1820 * with the previous entry when object is NULL. Here, we handle the 1821 * other cases, which are less common. 1822 */ 1823 vm_map_try_merge_entries(map, prev_entry, new_entry); 1824 vm_map_try_merge_entries(map, new_entry, next_entry); 1825 1826 if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) { 1827 vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset), 1828 end - start, cow & MAP_PREFAULT_PARTIAL); 1829 } 1830 1831 return (KERN_SUCCESS); 1832 } 1833 1834 /* 1835 * vm_map_findspace: 1836 * 1837 * Find the first fit (lowest VM address) for "length" free bytes 1838 * beginning at address >= start in the given map. 1839 * 1840 * In a vm_map_entry, "max_free" is the maximum amount of 1841 * contiguous free space between an entry in its subtree and a 1842 * neighbor of that entry. This allows finding a free region in 1843 * one path down the tree, so O(log n) amortized with splay 1844 * trees. 1845 * 1846 * The map must be locked, and leaves it so. 1847 * 1848 * Returns: starting address if sufficient space, 1849 * vm_map_max(map)-length+1 if insufficient space. 1850 */ 1851 vm_offset_t 1852 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length) 1853 { 1854 vm_map_entry_t header, llist, rlist, root, y; 1855 vm_size_t left_length, max_free_left, max_free_right; 1856 vm_offset_t gap_end; 1857 1858 VM_MAP_ASSERT_LOCKED(map); 1859 1860 /* 1861 * Request must fit within min/max VM address and must avoid 1862 * address wrap. 1863 */ 1864 start = MAX(start, vm_map_min(map)); 1865 if (start >= vm_map_max(map) || length > vm_map_max(map) - start) 1866 return (vm_map_max(map) - length + 1); 1867 1868 /* Empty tree means wide open address space. */ 1869 if (map->root == NULL) 1870 return (start); 1871 1872 /* 1873 * After splay_split, if start is within an entry, push it to the start 1874 * of the following gap. If rlist is at the end of the gap containing 1875 * start, save the end of that gap in gap_end to see if the gap is big 1876 * enough; otherwise set gap_end to start skip gap-checking and move 1877 * directly to a search of the right subtree. 1878 */ 1879 header = &map->header; 1880 root = vm_map_splay_split(map, start, length, &llist, &rlist); 1881 gap_end = rlist->start; 1882 if (root != NULL) { 1883 start = root->end; 1884 if (root->right != rlist) 1885 gap_end = start; 1886 max_free_left = vm_map_splay_merge_left(header, root, llist); 1887 max_free_right = vm_map_splay_merge_right(header, root, rlist); 1888 } else if (rlist != header) { 1889 root = rlist; 1890 rlist = root->left; 1891 max_free_left = vm_map_splay_merge_pred(header, root, llist); 1892 max_free_right = vm_map_splay_merge_right(header, root, rlist); 1893 } else { 1894 root = llist; 1895 llist = root->right; 1896 max_free_left = vm_map_splay_merge_left(header, root, llist); 1897 max_free_right = vm_map_splay_merge_succ(header, root, rlist); 1898 } 1899 root->max_free = vm_size_max(max_free_left, max_free_right); 1900 map->root = root; 1901 VM_MAP_ASSERT_CONSISTENT(map); 1902 if (length <= gap_end - start) 1903 return (start); 1904 1905 /* With max_free, can immediately tell if no solution. */ 1906 if (root->right == header || length > root->right->max_free) 1907 return (vm_map_max(map) - length + 1); 1908 1909 /* 1910 * Splay for the least large-enough gap in the right subtree. 1911 */ 1912 llist = rlist = header; 1913 for (left_length = 0;; 1914 left_length = vm_map_entry_max_free_left(root, llist)) { 1915 if (length <= left_length) 1916 SPLAY_LEFT_STEP(root, y, llist, rlist, 1917 length <= vm_map_entry_max_free_left(y, llist)); 1918 else 1919 SPLAY_RIGHT_STEP(root, y, llist, rlist, 1920 length > vm_map_entry_max_free_left(y, root)); 1921 if (root == NULL) 1922 break; 1923 } 1924 root = llist; 1925 llist = root->right; 1926 max_free_left = vm_map_splay_merge_left(header, root, llist); 1927 if (rlist == header) { 1928 root->max_free = vm_size_max(max_free_left, 1929 vm_map_splay_merge_succ(header, root, rlist)); 1930 } else { 1931 y = rlist; 1932 rlist = y->left; 1933 y->max_free = vm_size_max( 1934 vm_map_splay_merge_pred(root, y, root), 1935 vm_map_splay_merge_right(header, y, rlist)); 1936 root->max_free = vm_size_max(max_free_left, y->max_free); 1937 } 1938 map->root = root; 1939 VM_MAP_ASSERT_CONSISTENT(map); 1940 return (root->end); 1941 } 1942 1943 int 1944 vm_map_fixed(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1945 vm_offset_t start, vm_size_t length, vm_prot_t prot, 1946 vm_prot_t max, int cow) 1947 { 1948 vm_offset_t end; 1949 int result; 1950 1951 end = start + length; 1952 KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || 1953 object == NULL, 1954 ("vm_map_fixed: non-NULL backing object for stack")); 1955 vm_map_lock(map); 1956 VM_MAP_RANGE_CHECK(map, start, end); 1957 if ((cow & MAP_CHECK_EXCL) == 0) { 1958 result = vm_map_delete(map, start, end); 1959 if (result != KERN_SUCCESS) 1960 goto out; 1961 } 1962 if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { 1963 result = vm_map_stack_locked(map, start, length, sgrowsiz, 1964 prot, max, cow); 1965 } else { 1966 result = vm_map_insert(map, object, offset, start, end, 1967 prot, max, cow); 1968 } 1969 out: 1970 vm_map_unlock(map); 1971 return (result); 1972 } 1973 1974 static const int aslr_pages_rnd_64[2] = {0x1000, 0x10}; 1975 static const int aslr_pages_rnd_32[2] = {0x100, 0x4}; 1976 1977 static int cluster_anon = 1; 1978 SYSCTL_INT(_vm, OID_AUTO, cluster_anon, CTLFLAG_RW, 1979 &cluster_anon, 0, 1980 "Cluster anonymous mappings: 0 = no, 1 = yes if no hint, 2 = always"); 1981 1982 static bool 1983 clustering_anon_allowed(vm_offset_t addr, int cow) 1984 { 1985 1986 switch (cluster_anon) { 1987 case 0: 1988 return (false); 1989 case 1: 1990 return (addr == 0 || (cow & MAP_NO_HINT) != 0); 1991 case 2: 1992 default: 1993 return (true); 1994 } 1995 } 1996 1997 static long aslr_restarts; 1998 SYSCTL_LONG(_vm, OID_AUTO, aslr_restarts, CTLFLAG_RD, 1999 &aslr_restarts, 0, 2000 "Number of aslr failures"); 2001 2002 /* 2003 * Searches for the specified amount of free space in the given map with the 2004 * specified alignment. Performs an address-ordered, first-fit search from 2005 * the given address "*addr", with an optional upper bound "max_addr". If the 2006 * parameter "alignment" is zero, then the alignment is computed from the 2007 * given (object, offset) pair so as to enable the greatest possible use of 2008 * superpage mappings. Returns KERN_SUCCESS and the address of the free space 2009 * in "*addr" if successful. Otherwise, returns KERN_NO_SPACE. 2010 * 2011 * The map must be locked. Initially, there must be at least "length" bytes 2012 * of free space at the given address. 2013 */ 2014 static int 2015 vm_map_alignspace(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 2016 vm_offset_t *addr, vm_size_t length, vm_offset_t max_addr, 2017 vm_offset_t alignment) 2018 { 2019 vm_offset_t aligned_addr, free_addr; 2020 2021 VM_MAP_ASSERT_LOCKED(map); 2022 free_addr = *addr; 2023 KASSERT(free_addr == vm_map_findspace(map, free_addr, length), 2024 ("caller failed to provide space %#jx at address %p", 2025 (uintmax_t)length, (void *)free_addr)); 2026 for (;;) { 2027 /* 2028 * At the start of every iteration, the free space at address 2029 * "*addr" is at least "length" bytes. 2030 */ 2031 if (alignment == 0) 2032 pmap_align_superpage(object, offset, addr, length); 2033 else 2034 *addr = roundup2(*addr, alignment); 2035 aligned_addr = *addr; 2036 if (aligned_addr == free_addr) { 2037 /* 2038 * Alignment did not change "*addr", so "*addr" must 2039 * still provide sufficient free space. 2040 */ 2041 return (KERN_SUCCESS); 2042 } 2043 2044 /* 2045 * Test for address wrap on "*addr". A wrapped "*addr" could 2046 * be a valid address, in which case vm_map_findspace() cannot 2047 * be relied upon to fail. 2048 */ 2049 if (aligned_addr < free_addr) 2050 return (KERN_NO_SPACE); 2051 *addr = vm_map_findspace(map, aligned_addr, length); 2052 if (*addr + length > vm_map_max(map) || 2053 (max_addr != 0 && *addr + length > max_addr)) 2054 return (KERN_NO_SPACE); 2055 free_addr = *addr; 2056 if (free_addr == aligned_addr) { 2057 /* 2058 * If a successful call to vm_map_findspace() did not 2059 * change "*addr", then "*addr" must still be aligned 2060 * and provide sufficient free space. 2061 */ 2062 return (KERN_SUCCESS); 2063 } 2064 } 2065 } 2066 2067 int 2068 vm_map_find_aligned(vm_map_t map, vm_offset_t *addr, vm_size_t length, 2069 vm_offset_t max_addr, vm_offset_t alignment) 2070 { 2071 /* XXXKIB ASLR eh ? */ 2072 *addr = vm_map_findspace(map, *addr, length); 2073 if (*addr + length > vm_map_max(map) || 2074 (max_addr != 0 && *addr + length > max_addr)) 2075 return (KERN_NO_SPACE); 2076 return (vm_map_alignspace(map, NULL, 0, addr, length, max_addr, 2077 alignment)); 2078 } 2079 2080 /* 2081 * vm_map_find finds an unallocated region in the target address 2082 * map with the given length. The search is defined to be 2083 * first-fit from the specified address; the region found is 2084 * returned in the same parameter. 2085 * 2086 * If object is non-NULL, ref count must be bumped by caller 2087 * prior to making call to account for the new entry. 2088 */ 2089 int 2090 vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 2091 vm_offset_t *addr, /* IN/OUT */ 2092 vm_size_t length, vm_offset_t max_addr, int find_space, 2093 vm_prot_t prot, vm_prot_t max, int cow) 2094 { 2095 vm_offset_t alignment, curr_min_addr, min_addr; 2096 int gap, pidx, rv, try; 2097 bool cluster, en_aslr, update_anon; 2098 2099 KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || 2100 object == NULL, 2101 ("vm_map_find: non-NULL backing object for stack")); 2102 MPASS((cow & MAP_REMAP) == 0 || (find_space == VMFS_NO_SPACE && 2103 (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0)); 2104 if (find_space == VMFS_OPTIMAL_SPACE && (object == NULL || 2105 (object->flags & OBJ_COLORED) == 0)) 2106 find_space = VMFS_ANY_SPACE; 2107 if (find_space >> 8 != 0) { 2108 KASSERT((find_space & 0xff) == 0, ("bad VMFS flags")); 2109 alignment = (vm_offset_t)1 << (find_space >> 8); 2110 } else 2111 alignment = 0; 2112 en_aslr = (map->flags & MAP_ASLR) != 0; 2113 update_anon = cluster = clustering_anon_allowed(*addr, cow) && 2114 (map->flags & MAP_IS_SUB_MAP) == 0 && max_addr == 0 && 2115 find_space != VMFS_NO_SPACE && object == NULL && 2116 (cow & (MAP_INHERIT_SHARE | MAP_STACK_GROWS_UP | 2117 MAP_STACK_GROWS_DOWN)) == 0 && prot != PROT_NONE; 2118 curr_min_addr = min_addr = *addr; 2119 if (en_aslr && min_addr == 0 && !cluster && 2120 find_space != VMFS_NO_SPACE && 2121 (map->flags & MAP_ASLR_IGNSTART) != 0) 2122 curr_min_addr = min_addr = vm_map_min(map); 2123 try = 0; 2124 vm_map_lock(map); 2125 if (cluster) { 2126 curr_min_addr = map->anon_loc; 2127 if (curr_min_addr == 0) 2128 cluster = false; 2129 } 2130 if (find_space != VMFS_NO_SPACE) { 2131 KASSERT(find_space == VMFS_ANY_SPACE || 2132 find_space == VMFS_OPTIMAL_SPACE || 2133 find_space == VMFS_SUPER_SPACE || 2134 alignment != 0, ("unexpected VMFS flag")); 2135 again: 2136 /* 2137 * When creating an anonymous mapping, try clustering 2138 * with an existing anonymous mapping first. 2139 * 2140 * We make up to two attempts to find address space 2141 * for a given find_space value. The first attempt may 2142 * apply randomization or may cluster with an existing 2143 * anonymous mapping. If this first attempt fails, 2144 * perform a first-fit search of the available address 2145 * space. 2146 * 2147 * If all tries failed, and find_space is 2148 * VMFS_OPTIMAL_SPACE, fallback to VMFS_ANY_SPACE. 2149 * Again enable clustering and randomization. 2150 */ 2151 try++; 2152 MPASS(try <= 2); 2153 2154 if (try == 2) { 2155 /* 2156 * Second try: we failed either to find a 2157 * suitable region for randomizing the 2158 * allocation, or to cluster with an existing 2159 * mapping. Retry with free run. 2160 */ 2161 curr_min_addr = (map->flags & MAP_ASLR_IGNSTART) != 0 ? 2162 vm_map_min(map) : min_addr; 2163 atomic_add_long(&aslr_restarts, 1); 2164 } 2165 2166 if (try == 1 && en_aslr && !cluster) { 2167 /* 2168 * Find space for allocation, including 2169 * gap needed for later randomization. 2170 */ 2171 pidx = MAXPAGESIZES > 1 && pagesizes[1] != 0 && 2172 (find_space == VMFS_SUPER_SPACE || find_space == 2173 VMFS_OPTIMAL_SPACE) ? 1 : 0; 2174 gap = vm_map_max(map) > MAP_32BIT_MAX_ADDR && 2175 (max_addr == 0 || max_addr > MAP_32BIT_MAX_ADDR) ? 2176 aslr_pages_rnd_64[pidx] : aslr_pages_rnd_32[pidx]; 2177 *addr = vm_map_findspace(map, curr_min_addr, 2178 length + gap * pagesizes[pidx]); 2179 if (*addr + length + gap * pagesizes[pidx] > 2180 vm_map_max(map)) 2181 goto again; 2182 /* And randomize the start address. */ 2183 *addr += (arc4random() % gap) * pagesizes[pidx]; 2184 if (max_addr != 0 && *addr + length > max_addr) 2185 goto again; 2186 } else { 2187 *addr = vm_map_findspace(map, curr_min_addr, length); 2188 if (*addr + length > vm_map_max(map) || 2189 (max_addr != 0 && *addr + length > max_addr)) { 2190 if (cluster) { 2191 cluster = false; 2192 MPASS(try == 1); 2193 goto again; 2194 } 2195 rv = KERN_NO_SPACE; 2196 goto done; 2197 } 2198 } 2199 2200 if (find_space != VMFS_ANY_SPACE && 2201 (rv = vm_map_alignspace(map, object, offset, addr, length, 2202 max_addr, alignment)) != KERN_SUCCESS) { 2203 if (find_space == VMFS_OPTIMAL_SPACE) { 2204 find_space = VMFS_ANY_SPACE; 2205 curr_min_addr = min_addr; 2206 cluster = update_anon; 2207 try = 0; 2208 goto again; 2209 } 2210 goto done; 2211 } 2212 } else if ((cow & MAP_REMAP) != 0) { 2213 if (!vm_map_range_valid(map, *addr, *addr + length)) { 2214 rv = KERN_INVALID_ADDRESS; 2215 goto done; 2216 } 2217 rv = vm_map_delete(map, *addr, *addr + length); 2218 if (rv != KERN_SUCCESS) 2219 goto done; 2220 } 2221 if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { 2222 rv = vm_map_stack_locked(map, *addr, length, sgrowsiz, prot, 2223 max, cow); 2224 } else { 2225 rv = vm_map_insert(map, object, offset, *addr, *addr + length, 2226 prot, max, cow); 2227 } 2228 if (rv == KERN_SUCCESS && update_anon) 2229 map->anon_loc = *addr + length; 2230 done: 2231 vm_map_unlock(map); 2232 return (rv); 2233 } 2234 2235 /* 2236 * vm_map_find_min() is a variant of vm_map_find() that takes an 2237 * additional parameter (min_addr) and treats the given address 2238 * (*addr) differently. Specifically, it treats *addr as a hint 2239 * and not as the minimum address where the mapping is created. 2240 * 2241 * This function works in two phases. First, it tries to 2242 * allocate above the hint. If that fails and the hint is 2243 * greater than min_addr, it performs a second pass, replacing 2244 * the hint with min_addr as the minimum address for the 2245 * allocation. 2246 */ 2247 int 2248 vm_map_find_min(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 2249 vm_offset_t *addr, vm_size_t length, vm_offset_t min_addr, 2250 vm_offset_t max_addr, int find_space, vm_prot_t prot, vm_prot_t max, 2251 int cow) 2252 { 2253 vm_offset_t hint; 2254 int rv; 2255 2256 hint = *addr; 2257 if (hint == 0) { 2258 cow |= MAP_NO_HINT; 2259 *addr = hint = min_addr; 2260 } 2261 for (;;) { 2262 rv = vm_map_find(map, object, offset, addr, length, max_addr, 2263 find_space, prot, max, cow); 2264 if (rv == KERN_SUCCESS || min_addr >= hint) 2265 return (rv); 2266 *addr = hint = min_addr; 2267 } 2268 } 2269 2270 /* 2271 * A map entry with any of the following flags set must not be merged with 2272 * another entry. 2273 */ 2274 #define MAP_ENTRY_NOMERGE_MASK (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP | \ 2275 MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP | MAP_ENTRY_VN_EXEC) 2276 2277 static bool 2278 vm_map_mergeable_neighbors(vm_map_entry_t prev, vm_map_entry_t entry) 2279 { 2280 2281 KASSERT((prev->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 || 2282 (entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0, 2283 ("vm_map_mergeable_neighbors: neither %p nor %p are mergeable", 2284 prev, entry)); 2285 return (prev->end == entry->start && 2286 prev->object.vm_object == entry->object.vm_object && 2287 (prev->object.vm_object == NULL || 2288 prev->offset + (prev->end - prev->start) == entry->offset) && 2289 prev->eflags == entry->eflags && 2290 prev->protection == entry->protection && 2291 prev->max_protection == entry->max_protection && 2292 prev->inheritance == entry->inheritance && 2293 prev->wired_count == entry->wired_count && 2294 prev->cred == entry->cred); 2295 } 2296 2297 static void 2298 vm_map_merged_neighbor_dispose(vm_map_t map, vm_map_entry_t entry) 2299 { 2300 2301 /* 2302 * If the backing object is a vnode object, vm_object_deallocate() 2303 * calls vrele(). However, vrele() does not lock the vnode because 2304 * the vnode has additional references. Thus, the map lock can be 2305 * kept without causing a lock-order reversal with the vnode lock. 2306 * 2307 * Since we count the number of virtual page mappings in 2308 * object->un_pager.vnp.writemappings, the writemappings value 2309 * should not be adjusted when the entry is disposed of. 2310 */ 2311 if (entry->object.vm_object != NULL) 2312 vm_object_deallocate(entry->object.vm_object); 2313 if (entry->cred != NULL) 2314 crfree(entry->cred); 2315 vm_map_entry_dispose(map, entry); 2316 } 2317 2318 /* 2319 * vm_map_try_merge_entries: 2320 * 2321 * Compare the given map entry to its predecessor, and merge its precessor 2322 * into it if possible. The entry remains valid, and may be extended. 2323 * The predecessor may be deleted. 2324 * 2325 * The map must be locked. 2326 */ 2327 void 2328 vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev_entry, 2329 vm_map_entry_t entry) 2330 { 2331 2332 VM_MAP_ASSERT_LOCKED(map); 2333 if ((entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 && 2334 vm_map_mergeable_neighbors(prev_entry, entry)) { 2335 vm_map_entry_unlink(map, prev_entry, UNLINK_MERGE_NEXT); 2336 vm_map_merged_neighbor_dispose(map, prev_entry); 2337 } 2338 } 2339 2340 /* 2341 * vm_map_entry_back: 2342 * 2343 * Allocate an object to back a map entry. 2344 */ 2345 static inline void 2346 vm_map_entry_back(vm_map_entry_t entry) 2347 { 2348 vm_object_t object; 2349 2350 KASSERT(entry->object.vm_object == NULL, 2351 ("map entry %p has backing object", entry)); 2352 KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, 2353 ("map entry %p is a submap", entry)); 2354 object = vm_object_allocate_anon(atop(entry->end - entry->start), NULL, 2355 entry->cred, entry->end - entry->start); 2356 entry->object.vm_object = object; 2357 entry->offset = 0; 2358 entry->cred = NULL; 2359 } 2360 2361 /* 2362 * vm_map_entry_charge_object 2363 * 2364 * If there is no object backing this entry, create one. Otherwise, if 2365 * the entry has cred, give it to the backing object. 2366 */ 2367 static inline void 2368 vm_map_entry_charge_object(vm_map_t map, vm_map_entry_t entry) 2369 { 2370 2371 VM_MAP_ASSERT_LOCKED(map); 2372 KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, 2373 ("map entry %p is a submap", entry)); 2374 if (entry->object.vm_object == NULL && !map->system_map && 2375 (entry->eflags & MAP_ENTRY_GUARD) == 0) 2376 vm_map_entry_back(entry); 2377 else if (entry->object.vm_object != NULL && 2378 ((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) && 2379 entry->cred != NULL) { 2380 VM_OBJECT_WLOCK(entry->object.vm_object); 2381 KASSERT(entry->object.vm_object->cred == NULL, 2382 ("OVERCOMMIT: %s: both cred e %p", __func__, entry)); 2383 entry->object.vm_object->cred = entry->cred; 2384 entry->object.vm_object->charge = entry->end - entry->start; 2385 VM_OBJECT_WUNLOCK(entry->object.vm_object); 2386 entry->cred = NULL; 2387 } 2388 } 2389 2390 /* 2391 * vm_map_entry_clone 2392 * 2393 * Create a duplicate map entry for clipping. 2394 */ 2395 static vm_map_entry_t 2396 vm_map_entry_clone(vm_map_t map, vm_map_entry_t entry) 2397 { 2398 vm_map_entry_t new_entry; 2399 2400 VM_MAP_ASSERT_LOCKED(map); 2401 2402 /* 2403 * Create a backing object now, if none exists, so that more individual 2404 * objects won't be created after the map entry is split. 2405 */ 2406 vm_map_entry_charge_object(map, entry); 2407 2408 /* Clone the entry. */ 2409 new_entry = vm_map_entry_create(map); 2410 *new_entry = *entry; 2411 if (new_entry->cred != NULL) 2412 crhold(entry->cred); 2413 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 2414 vm_object_reference(new_entry->object.vm_object); 2415 vm_map_entry_set_vnode_text(new_entry, true); 2416 /* 2417 * The object->un_pager.vnp.writemappings for the object of 2418 * MAP_ENTRY_WRITECNT type entry shall be kept as is here. The 2419 * virtual pages are re-distributed among the clipped entries, 2420 * so the sum is left the same. 2421 */ 2422 } 2423 return (new_entry); 2424 } 2425 2426 /* 2427 * vm_map_clip_start: [ internal use only ] 2428 * 2429 * Asserts that the given entry begins at or after 2430 * the specified address; if necessary, 2431 * it splits the entry into two. 2432 */ 2433 static int 2434 vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t startaddr) 2435 { 2436 vm_map_entry_t new_entry; 2437 int bdry_idx; 2438 2439 if (!map->system_map) 2440 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 2441 "%s: map %p entry %p start 0x%jx", __func__, map, entry, 2442 (uintmax_t)startaddr); 2443 2444 if (startaddr <= entry->start) 2445 return (KERN_SUCCESS); 2446 2447 VM_MAP_ASSERT_LOCKED(map); 2448 KASSERT(entry->end > startaddr && entry->start < startaddr, 2449 ("%s: invalid clip of entry %p", __func__, entry)); 2450 2451 bdry_idx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry); 2452 if (bdry_idx != 0) { 2453 if ((startaddr & (pagesizes[bdry_idx] - 1)) != 0) 2454 return (KERN_INVALID_ARGUMENT); 2455 } 2456 2457 new_entry = vm_map_entry_clone(map, entry); 2458 2459 /* 2460 * Split off the front portion. Insert the new entry BEFORE this one, 2461 * so that this entry has the specified starting address. 2462 */ 2463 new_entry->end = startaddr; 2464 vm_map_entry_link(map, new_entry); 2465 return (KERN_SUCCESS); 2466 } 2467 2468 /* 2469 * vm_map_lookup_clip_start: 2470 * 2471 * Find the entry at or just after 'start', and clip it if 'start' is in 2472 * the interior of the entry. Return entry after 'start', and in 2473 * prev_entry set the entry before 'start'. 2474 */ 2475 static int 2476 vm_map_lookup_clip_start(vm_map_t map, vm_offset_t start, 2477 vm_map_entry_t *res_entry, vm_map_entry_t *prev_entry) 2478 { 2479 vm_map_entry_t entry; 2480 int rv; 2481 2482 if (!map->system_map) 2483 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 2484 "%s: map %p start 0x%jx prev %p", __func__, map, 2485 (uintmax_t)start, prev_entry); 2486 2487 if (vm_map_lookup_entry(map, start, prev_entry)) { 2488 entry = *prev_entry; 2489 rv = vm_map_clip_start(map, entry, start); 2490 if (rv != KERN_SUCCESS) 2491 return (rv); 2492 *prev_entry = vm_map_entry_pred(entry); 2493 } else 2494 entry = vm_map_entry_succ(*prev_entry); 2495 *res_entry = entry; 2496 return (KERN_SUCCESS); 2497 } 2498 2499 /* 2500 * vm_map_clip_end: [ internal use only ] 2501 * 2502 * Asserts that the given entry ends at or before 2503 * the specified address; if necessary, 2504 * it splits the entry into two. 2505 */ 2506 static int 2507 vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t endaddr) 2508 { 2509 vm_map_entry_t new_entry; 2510 int bdry_idx; 2511 2512 if (!map->system_map) 2513 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 2514 "%s: map %p entry %p end 0x%jx", __func__, map, entry, 2515 (uintmax_t)endaddr); 2516 2517 if (endaddr >= entry->end) 2518 return (KERN_SUCCESS); 2519 2520 VM_MAP_ASSERT_LOCKED(map); 2521 KASSERT(entry->start < endaddr && entry->end > endaddr, 2522 ("%s: invalid clip of entry %p", __func__, entry)); 2523 2524 bdry_idx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry); 2525 if (bdry_idx != 0) { 2526 if ((endaddr & (pagesizes[bdry_idx] - 1)) != 0) 2527 return (KERN_INVALID_ARGUMENT); 2528 } 2529 2530 new_entry = vm_map_entry_clone(map, entry); 2531 2532 /* 2533 * Split off the back portion. Insert the new entry AFTER this one, 2534 * so that this entry has the specified ending address. 2535 */ 2536 new_entry->start = endaddr; 2537 vm_map_entry_link(map, new_entry); 2538 2539 return (KERN_SUCCESS); 2540 } 2541 2542 /* 2543 * vm_map_submap: [ kernel use only ] 2544 * 2545 * Mark the given range as handled by a subordinate map. 2546 * 2547 * This range must have been created with vm_map_find, 2548 * and no other operations may have been performed on this 2549 * range prior to calling vm_map_submap. 2550 * 2551 * Only a limited number of operations can be performed 2552 * within this rage after calling vm_map_submap: 2553 * vm_fault 2554 * [Don't try vm_map_copy!] 2555 * 2556 * To remove a submapping, one must first remove the 2557 * range from the superior map, and then destroy the 2558 * submap (if desired). [Better yet, don't try it.] 2559 */ 2560 int 2561 vm_map_submap( 2562 vm_map_t map, 2563 vm_offset_t start, 2564 vm_offset_t end, 2565 vm_map_t submap) 2566 { 2567 vm_map_entry_t entry; 2568 int result; 2569 2570 result = KERN_INVALID_ARGUMENT; 2571 2572 vm_map_lock(submap); 2573 submap->flags |= MAP_IS_SUB_MAP; 2574 vm_map_unlock(submap); 2575 2576 vm_map_lock(map); 2577 VM_MAP_RANGE_CHECK(map, start, end); 2578 if (vm_map_lookup_entry(map, start, &entry) && entry->end >= end && 2579 (entry->eflags & MAP_ENTRY_COW) == 0 && 2580 entry->object.vm_object == NULL) { 2581 result = vm_map_clip_start(map, entry, start); 2582 if (result != KERN_SUCCESS) 2583 goto unlock; 2584 result = vm_map_clip_end(map, entry, end); 2585 if (result != KERN_SUCCESS) 2586 goto unlock; 2587 entry->object.sub_map = submap; 2588 entry->eflags |= MAP_ENTRY_IS_SUB_MAP; 2589 result = KERN_SUCCESS; 2590 } 2591 unlock: 2592 vm_map_unlock(map); 2593 2594 if (result != KERN_SUCCESS) { 2595 vm_map_lock(submap); 2596 submap->flags &= ~MAP_IS_SUB_MAP; 2597 vm_map_unlock(submap); 2598 } 2599 return (result); 2600 } 2601 2602 /* 2603 * The maximum number of pages to map if MAP_PREFAULT_PARTIAL is specified 2604 */ 2605 #define MAX_INIT_PT 96 2606 2607 /* 2608 * vm_map_pmap_enter: 2609 * 2610 * Preload the specified map's pmap with mappings to the specified 2611 * object's memory-resident pages. No further physical pages are 2612 * allocated, and no further virtual pages are retrieved from secondary 2613 * storage. If the specified flags include MAP_PREFAULT_PARTIAL, then a 2614 * limited number of page mappings are created at the low-end of the 2615 * specified address range. (For this purpose, a superpage mapping 2616 * counts as one page mapping.) Otherwise, all resident pages within 2617 * the specified address range are mapped. 2618 */ 2619 static void 2620 vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot, 2621 vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags) 2622 { 2623 vm_offset_t start; 2624 vm_page_t p, p_start; 2625 vm_pindex_t mask, psize, threshold, tmpidx; 2626 2627 if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL) 2628 return; 2629 if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { 2630 VM_OBJECT_WLOCK(object); 2631 if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { 2632 pmap_object_init_pt(map->pmap, addr, object, pindex, 2633 size); 2634 VM_OBJECT_WUNLOCK(object); 2635 return; 2636 } 2637 VM_OBJECT_LOCK_DOWNGRADE(object); 2638 } else 2639 VM_OBJECT_RLOCK(object); 2640 2641 psize = atop(size); 2642 if (psize + pindex > object->size) { 2643 if (pindex >= object->size) { 2644 VM_OBJECT_RUNLOCK(object); 2645 return; 2646 } 2647 psize = object->size - pindex; 2648 } 2649 2650 start = 0; 2651 p_start = NULL; 2652 threshold = MAX_INIT_PT; 2653 2654 p = vm_page_find_least(object, pindex); 2655 /* 2656 * Assert: the variable p is either (1) the page with the 2657 * least pindex greater than or equal to the parameter pindex 2658 * or (2) NULL. 2659 */ 2660 for (; 2661 p != NULL && (tmpidx = p->pindex - pindex) < psize; 2662 p = TAILQ_NEXT(p, listq)) { 2663 /* 2664 * don't allow an madvise to blow away our really 2665 * free pages allocating pv entries. 2666 */ 2667 if (((flags & MAP_PREFAULT_MADVISE) != 0 && 2668 vm_page_count_severe()) || 2669 ((flags & MAP_PREFAULT_PARTIAL) != 0 && 2670 tmpidx >= threshold)) { 2671 psize = tmpidx; 2672 break; 2673 } 2674 if (vm_page_all_valid(p)) { 2675 if (p_start == NULL) { 2676 start = addr + ptoa(tmpidx); 2677 p_start = p; 2678 } 2679 /* Jump ahead if a superpage mapping is possible. */ 2680 if (p->psind > 0 && ((addr + ptoa(tmpidx)) & 2681 (pagesizes[p->psind] - 1)) == 0) { 2682 mask = atop(pagesizes[p->psind]) - 1; 2683 if (tmpidx + mask < psize && 2684 vm_page_ps_test(p, PS_ALL_VALID, NULL)) { 2685 p += mask; 2686 threshold += mask; 2687 } 2688 } 2689 } else if (p_start != NULL) { 2690 pmap_enter_object(map->pmap, start, addr + 2691 ptoa(tmpidx), p_start, prot); 2692 p_start = NULL; 2693 } 2694 } 2695 if (p_start != NULL) 2696 pmap_enter_object(map->pmap, start, addr + ptoa(psize), 2697 p_start, prot); 2698 VM_OBJECT_RUNLOCK(object); 2699 } 2700 2701 /* 2702 * vm_map_protect: 2703 * 2704 * Sets the protection and/or the maximum protection of the 2705 * specified address region in the target map. 2706 */ 2707 int 2708 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, 2709 vm_prot_t new_prot, vm_prot_t new_maxprot, int flags) 2710 { 2711 vm_map_entry_t entry, first_entry, in_tran, prev_entry; 2712 vm_object_t obj; 2713 struct ucred *cred; 2714 vm_prot_t old_prot; 2715 int rv; 2716 2717 if (start == end) 2718 return (KERN_SUCCESS); 2719 2720 if ((flags & (VM_MAP_PROTECT_SET_PROT | VM_MAP_PROTECT_SET_MAXPROT)) == 2721 (VM_MAP_PROTECT_SET_PROT | VM_MAP_PROTECT_SET_MAXPROT) && 2722 (new_prot & new_maxprot) != new_prot) 2723 return (KERN_OUT_OF_BOUNDS); 2724 2725 again: 2726 in_tran = NULL; 2727 vm_map_lock(map); 2728 2729 if ((map->flags & MAP_WXORX) != 0 && 2730 (flags & VM_MAP_PROTECT_SET_PROT) != 0 && 2731 (new_prot & (VM_PROT_WRITE | VM_PROT_EXECUTE)) == (VM_PROT_WRITE | 2732 VM_PROT_EXECUTE)) { 2733 vm_map_unlock(map); 2734 return (KERN_PROTECTION_FAILURE); 2735 } 2736 2737 /* 2738 * Ensure that we are not concurrently wiring pages. vm_map_wire() may 2739 * need to fault pages into the map and will drop the map lock while 2740 * doing so, and the VM object may end up in an inconsistent state if we 2741 * update the protection on the map entry in between faults. 2742 */ 2743 vm_map_wait_busy(map); 2744 2745 VM_MAP_RANGE_CHECK(map, start, end); 2746 2747 if (!vm_map_lookup_entry(map, start, &first_entry)) 2748 first_entry = vm_map_entry_succ(first_entry); 2749 2750 /* 2751 * Make a first pass to check for protection violations. 2752 */ 2753 for (entry = first_entry; entry->start < end; 2754 entry = vm_map_entry_succ(entry)) { 2755 if ((entry->eflags & MAP_ENTRY_GUARD) != 0) 2756 continue; 2757 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) { 2758 vm_map_unlock(map); 2759 return (KERN_INVALID_ARGUMENT); 2760 } 2761 if ((flags & VM_MAP_PROTECT_SET_PROT) == 0) 2762 new_prot = entry->protection; 2763 if ((flags & VM_MAP_PROTECT_SET_MAXPROT) == 0) 2764 new_maxprot = entry->max_protection; 2765 if ((new_prot & entry->max_protection) != new_prot || 2766 (new_maxprot & entry->max_protection) != new_maxprot) { 2767 vm_map_unlock(map); 2768 return (KERN_PROTECTION_FAILURE); 2769 } 2770 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0) 2771 in_tran = entry; 2772 } 2773 2774 /* 2775 * Postpone the operation until all in-transition map entries have 2776 * stabilized. An in-transition entry might already have its pages 2777 * wired and wired_count incremented, but not yet have its 2778 * MAP_ENTRY_USER_WIRED flag set. In which case, we would fail to call 2779 * vm_fault_copy_entry() in the final loop below. 2780 */ 2781 if (in_tran != NULL) { 2782 in_tran->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 2783 vm_map_unlock_and_wait(map, 0); 2784 goto again; 2785 } 2786 2787 /* 2788 * Before changing the protections, try to reserve swap space for any 2789 * private (i.e., copy-on-write) mappings that are transitioning from 2790 * read-only to read/write access. If a reservation fails, break out 2791 * of this loop early and let the next loop simplify the entries, since 2792 * some may now be mergeable. 2793 */ 2794 rv = vm_map_clip_start(map, first_entry, start); 2795 if (rv != KERN_SUCCESS) { 2796 vm_map_unlock(map); 2797 return (rv); 2798 } 2799 for (entry = first_entry; entry->start < end; 2800 entry = vm_map_entry_succ(entry)) { 2801 rv = vm_map_clip_end(map, entry, end); 2802 if (rv != KERN_SUCCESS) { 2803 vm_map_unlock(map); 2804 return (rv); 2805 } 2806 2807 if ((flags & VM_MAP_PROTECT_SET_PROT) == 0 || 2808 ((new_prot & ~entry->protection) & VM_PROT_WRITE) == 0 || 2809 ENTRY_CHARGED(entry) || 2810 (entry->eflags & MAP_ENTRY_GUARD) != 0) 2811 continue; 2812 2813 cred = curthread->td_ucred; 2814 obj = entry->object.vm_object; 2815 2816 if (obj == NULL || 2817 (entry->eflags & MAP_ENTRY_NEEDS_COPY) != 0) { 2818 if (!swap_reserve(entry->end - entry->start)) { 2819 rv = KERN_RESOURCE_SHORTAGE; 2820 end = entry->end; 2821 break; 2822 } 2823 crhold(cred); 2824 entry->cred = cred; 2825 continue; 2826 } 2827 2828 VM_OBJECT_WLOCK(obj); 2829 if ((obj->flags & OBJ_SWAP) == 0) { 2830 VM_OBJECT_WUNLOCK(obj); 2831 continue; 2832 } 2833 2834 /* 2835 * Charge for the whole object allocation now, since 2836 * we cannot distinguish between non-charged and 2837 * charged clipped mapping of the same object later. 2838 */ 2839 KASSERT(obj->charge == 0, 2840 ("vm_map_protect: object %p overcharged (entry %p)", 2841 obj, entry)); 2842 if (!swap_reserve(ptoa(obj->size))) { 2843 VM_OBJECT_WUNLOCK(obj); 2844 rv = KERN_RESOURCE_SHORTAGE; 2845 end = entry->end; 2846 break; 2847 } 2848 2849 crhold(cred); 2850 obj->cred = cred; 2851 obj->charge = ptoa(obj->size); 2852 VM_OBJECT_WUNLOCK(obj); 2853 } 2854 2855 /* 2856 * If enough swap space was available, go back and fix up protections. 2857 * Otherwise, just simplify entries, since some may have been modified. 2858 * [Note that clipping is not necessary the second time.] 2859 */ 2860 for (prev_entry = vm_map_entry_pred(first_entry), entry = first_entry; 2861 entry->start < end; 2862 vm_map_try_merge_entries(map, prev_entry, entry), 2863 prev_entry = entry, entry = vm_map_entry_succ(entry)) { 2864 if (rv != KERN_SUCCESS || 2865 (entry->eflags & MAP_ENTRY_GUARD) != 0) 2866 continue; 2867 2868 old_prot = entry->protection; 2869 2870 if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0) { 2871 entry->max_protection = new_maxprot; 2872 entry->protection = new_maxprot & old_prot; 2873 } 2874 if ((flags & VM_MAP_PROTECT_SET_PROT) != 0) 2875 entry->protection = new_prot; 2876 2877 /* 2878 * For user wired map entries, the normal lazy evaluation of 2879 * write access upgrades through soft page faults is 2880 * undesirable. Instead, immediately copy any pages that are 2881 * copy-on-write and enable write access in the physical map. 2882 */ 2883 if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0 && 2884 (entry->protection & VM_PROT_WRITE) != 0 && 2885 (old_prot & VM_PROT_WRITE) == 0) 2886 vm_fault_copy_entry(map, map, entry, entry, NULL); 2887 2888 /* 2889 * When restricting access, update the physical map. Worry 2890 * about copy-on-write here. 2891 */ 2892 if ((old_prot & ~entry->protection) != 0) { 2893 #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ 2894 VM_PROT_ALL) 2895 pmap_protect(map->pmap, entry->start, 2896 entry->end, 2897 entry->protection & MASK(entry)); 2898 #undef MASK 2899 } 2900 } 2901 vm_map_try_merge_entries(map, prev_entry, entry); 2902 vm_map_unlock(map); 2903 return (rv); 2904 } 2905 2906 /* 2907 * vm_map_madvise: 2908 * 2909 * This routine traverses a processes map handling the madvise 2910 * system call. Advisories are classified as either those effecting 2911 * the vm_map_entry structure, or those effecting the underlying 2912 * objects. 2913 */ 2914 int 2915 vm_map_madvise( 2916 vm_map_t map, 2917 vm_offset_t start, 2918 vm_offset_t end, 2919 int behav) 2920 { 2921 vm_map_entry_t entry, prev_entry; 2922 int rv; 2923 bool modify_map; 2924 2925 /* 2926 * Some madvise calls directly modify the vm_map_entry, in which case 2927 * we need to use an exclusive lock on the map and we need to perform 2928 * various clipping operations. Otherwise we only need a read-lock 2929 * on the map. 2930 */ 2931 switch(behav) { 2932 case MADV_NORMAL: 2933 case MADV_SEQUENTIAL: 2934 case MADV_RANDOM: 2935 case MADV_NOSYNC: 2936 case MADV_AUTOSYNC: 2937 case MADV_NOCORE: 2938 case MADV_CORE: 2939 if (start == end) 2940 return (0); 2941 modify_map = true; 2942 vm_map_lock(map); 2943 break; 2944 case MADV_WILLNEED: 2945 case MADV_DONTNEED: 2946 case MADV_FREE: 2947 if (start == end) 2948 return (0); 2949 modify_map = false; 2950 vm_map_lock_read(map); 2951 break; 2952 default: 2953 return (EINVAL); 2954 } 2955 2956 /* 2957 * Locate starting entry and clip if necessary. 2958 */ 2959 VM_MAP_RANGE_CHECK(map, start, end); 2960 2961 if (modify_map) { 2962 /* 2963 * madvise behaviors that are implemented in the vm_map_entry. 2964 * 2965 * We clip the vm_map_entry so that behavioral changes are 2966 * limited to the specified address range. 2967 */ 2968 rv = vm_map_lookup_clip_start(map, start, &entry, &prev_entry); 2969 if (rv != KERN_SUCCESS) { 2970 vm_map_unlock(map); 2971 return (vm_mmap_to_errno(rv)); 2972 } 2973 2974 for (; entry->start < end; prev_entry = entry, 2975 entry = vm_map_entry_succ(entry)) { 2976 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) 2977 continue; 2978 2979 rv = vm_map_clip_end(map, entry, end); 2980 if (rv != KERN_SUCCESS) { 2981 vm_map_unlock(map); 2982 return (vm_mmap_to_errno(rv)); 2983 } 2984 2985 switch (behav) { 2986 case MADV_NORMAL: 2987 vm_map_entry_set_behavior(entry, 2988 MAP_ENTRY_BEHAV_NORMAL); 2989 break; 2990 case MADV_SEQUENTIAL: 2991 vm_map_entry_set_behavior(entry, 2992 MAP_ENTRY_BEHAV_SEQUENTIAL); 2993 break; 2994 case MADV_RANDOM: 2995 vm_map_entry_set_behavior(entry, 2996 MAP_ENTRY_BEHAV_RANDOM); 2997 break; 2998 case MADV_NOSYNC: 2999 entry->eflags |= MAP_ENTRY_NOSYNC; 3000 break; 3001 case MADV_AUTOSYNC: 3002 entry->eflags &= ~MAP_ENTRY_NOSYNC; 3003 break; 3004 case MADV_NOCORE: 3005 entry->eflags |= MAP_ENTRY_NOCOREDUMP; 3006 break; 3007 case MADV_CORE: 3008 entry->eflags &= ~MAP_ENTRY_NOCOREDUMP; 3009 break; 3010 default: 3011 break; 3012 } 3013 vm_map_try_merge_entries(map, prev_entry, entry); 3014 } 3015 vm_map_try_merge_entries(map, prev_entry, entry); 3016 vm_map_unlock(map); 3017 } else { 3018 vm_pindex_t pstart, pend; 3019 3020 /* 3021 * madvise behaviors that are implemented in the underlying 3022 * vm_object. 3023 * 3024 * Since we don't clip the vm_map_entry, we have to clip 3025 * the vm_object pindex and count. 3026 */ 3027 if (!vm_map_lookup_entry(map, start, &entry)) 3028 entry = vm_map_entry_succ(entry); 3029 for (; entry->start < end; 3030 entry = vm_map_entry_succ(entry)) { 3031 vm_offset_t useEnd, useStart; 3032 3033 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) 3034 continue; 3035 3036 /* 3037 * MADV_FREE would otherwise rewind time to 3038 * the creation of the shadow object. Because 3039 * we hold the VM map read-locked, neither the 3040 * entry's object nor the presence of a 3041 * backing object can change. 3042 */ 3043 if (behav == MADV_FREE && 3044 entry->object.vm_object != NULL && 3045 entry->object.vm_object->backing_object != NULL) 3046 continue; 3047 3048 pstart = OFF_TO_IDX(entry->offset); 3049 pend = pstart + atop(entry->end - entry->start); 3050 useStart = entry->start; 3051 useEnd = entry->end; 3052 3053 if (entry->start < start) { 3054 pstart += atop(start - entry->start); 3055 useStart = start; 3056 } 3057 if (entry->end > end) { 3058 pend -= atop(entry->end - end); 3059 useEnd = end; 3060 } 3061 3062 if (pstart >= pend) 3063 continue; 3064 3065 /* 3066 * Perform the pmap_advise() before clearing 3067 * PGA_REFERENCED in vm_page_advise(). Otherwise, a 3068 * concurrent pmap operation, such as pmap_remove(), 3069 * could clear a reference in the pmap and set 3070 * PGA_REFERENCED on the page before the pmap_advise() 3071 * had completed. Consequently, the page would appear 3072 * referenced based upon an old reference that 3073 * occurred before this pmap_advise() ran. 3074 */ 3075 if (behav == MADV_DONTNEED || behav == MADV_FREE) 3076 pmap_advise(map->pmap, useStart, useEnd, 3077 behav); 3078 3079 vm_object_madvise(entry->object.vm_object, pstart, 3080 pend, behav); 3081 3082 /* 3083 * Pre-populate paging structures in the 3084 * WILLNEED case. For wired entries, the 3085 * paging structures are already populated. 3086 */ 3087 if (behav == MADV_WILLNEED && 3088 entry->wired_count == 0) { 3089 vm_map_pmap_enter(map, 3090 useStart, 3091 entry->protection, 3092 entry->object.vm_object, 3093 pstart, 3094 ptoa(pend - pstart), 3095 MAP_PREFAULT_MADVISE 3096 ); 3097 } 3098 } 3099 vm_map_unlock_read(map); 3100 } 3101 return (0); 3102 } 3103 3104 /* 3105 * vm_map_inherit: 3106 * 3107 * Sets the inheritance of the specified address 3108 * range in the target map. Inheritance 3109 * affects how the map will be shared with 3110 * child maps at the time of vmspace_fork. 3111 */ 3112 int 3113 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, 3114 vm_inherit_t new_inheritance) 3115 { 3116 vm_map_entry_t entry, lentry, prev_entry, start_entry; 3117 int rv; 3118 3119 switch (new_inheritance) { 3120 case VM_INHERIT_NONE: 3121 case VM_INHERIT_COPY: 3122 case VM_INHERIT_SHARE: 3123 case VM_INHERIT_ZERO: 3124 break; 3125 default: 3126 return (KERN_INVALID_ARGUMENT); 3127 } 3128 if (start == end) 3129 return (KERN_SUCCESS); 3130 vm_map_lock(map); 3131 VM_MAP_RANGE_CHECK(map, start, end); 3132 rv = vm_map_lookup_clip_start(map, start, &start_entry, &prev_entry); 3133 if (rv != KERN_SUCCESS) 3134 goto unlock; 3135 if (vm_map_lookup_entry(map, end - 1, &lentry)) { 3136 rv = vm_map_clip_end(map, lentry, end); 3137 if (rv != KERN_SUCCESS) 3138 goto unlock; 3139 } 3140 if (new_inheritance == VM_INHERIT_COPY) { 3141 for (entry = start_entry; entry->start < end; 3142 prev_entry = entry, entry = vm_map_entry_succ(entry)) { 3143 if ((entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK) 3144 != 0) { 3145 rv = KERN_INVALID_ARGUMENT; 3146 goto unlock; 3147 } 3148 } 3149 } 3150 for (entry = start_entry; entry->start < end; prev_entry = entry, 3151 entry = vm_map_entry_succ(entry)) { 3152 KASSERT(entry->end <= end, ("non-clipped entry %p end %jx %jx", 3153 entry, (uintmax_t)entry->end, (uintmax_t)end)); 3154 if ((entry->eflags & MAP_ENTRY_GUARD) == 0 || 3155 new_inheritance != VM_INHERIT_ZERO) 3156 entry->inheritance = new_inheritance; 3157 vm_map_try_merge_entries(map, prev_entry, entry); 3158 } 3159 vm_map_try_merge_entries(map, prev_entry, entry); 3160 unlock: 3161 vm_map_unlock(map); 3162 return (rv); 3163 } 3164 3165 /* 3166 * vm_map_entry_in_transition: 3167 * 3168 * Release the map lock, and sleep until the entry is no longer in 3169 * transition. Awake and acquire the map lock. If the map changed while 3170 * another held the lock, lookup a possibly-changed entry at or after the 3171 * 'start' position of the old entry. 3172 */ 3173 static vm_map_entry_t 3174 vm_map_entry_in_transition(vm_map_t map, vm_offset_t in_start, 3175 vm_offset_t *io_end, bool holes_ok, vm_map_entry_t in_entry) 3176 { 3177 vm_map_entry_t entry; 3178 vm_offset_t start; 3179 u_int last_timestamp; 3180 3181 VM_MAP_ASSERT_LOCKED(map); 3182 KASSERT((in_entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, 3183 ("not in-tranition map entry %p", in_entry)); 3184 /* 3185 * We have not yet clipped the entry. 3186 */ 3187 start = MAX(in_start, in_entry->start); 3188 in_entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 3189 last_timestamp = map->timestamp; 3190 if (vm_map_unlock_and_wait(map, 0)) { 3191 /* 3192 * Allow interruption of user wiring/unwiring? 3193 */ 3194 } 3195 vm_map_lock(map); 3196 if (last_timestamp + 1 == map->timestamp) 3197 return (in_entry); 3198 3199 /* 3200 * Look again for the entry because the map was modified while it was 3201 * unlocked. Specifically, the entry may have been clipped, merged, or 3202 * deleted. 3203 */ 3204 if (!vm_map_lookup_entry(map, start, &entry)) { 3205 if (!holes_ok) { 3206 *io_end = start; 3207 return (NULL); 3208 } 3209 entry = vm_map_entry_succ(entry); 3210 } 3211 return (entry); 3212 } 3213 3214 /* 3215 * vm_map_unwire: 3216 * 3217 * Implements both kernel and user unwiring. 3218 */ 3219 int 3220 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end, 3221 int flags) 3222 { 3223 vm_map_entry_t entry, first_entry, next_entry, prev_entry; 3224 int rv; 3225 bool holes_ok, need_wakeup, user_unwire; 3226 3227 if (start == end) 3228 return (KERN_SUCCESS); 3229 holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0; 3230 user_unwire = (flags & VM_MAP_WIRE_USER) != 0; 3231 vm_map_lock(map); 3232 VM_MAP_RANGE_CHECK(map, start, end); 3233 if (!vm_map_lookup_entry(map, start, &first_entry)) { 3234 if (holes_ok) 3235 first_entry = vm_map_entry_succ(first_entry); 3236 else { 3237 vm_map_unlock(map); 3238 return (KERN_INVALID_ADDRESS); 3239 } 3240 } 3241 rv = KERN_SUCCESS; 3242 for (entry = first_entry; entry->start < end; entry = next_entry) { 3243 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 3244 /* 3245 * We have not yet clipped the entry. 3246 */ 3247 next_entry = vm_map_entry_in_transition(map, start, 3248 &end, holes_ok, entry); 3249 if (next_entry == NULL) { 3250 if (entry == first_entry) { 3251 vm_map_unlock(map); 3252 return (KERN_INVALID_ADDRESS); 3253 } 3254 rv = KERN_INVALID_ADDRESS; 3255 break; 3256 } 3257 first_entry = (entry == first_entry) ? 3258 next_entry : NULL; 3259 continue; 3260 } 3261 rv = vm_map_clip_start(map, entry, start); 3262 if (rv != KERN_SUCCESS) 3263 break; 3264 rv = vm_map_clip_end(map, entry, end); 3265 if (rv != KERN_SUCCESS) 3266 break; 3267 3268 /* 3269 * Mark the entry in case the map lock is released. (See 3270 * above.) 3271 */ 3272 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && 3273 entry->wiring_thread == NULL, 3274 ("owned map entry %p", entry)); 3275 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 3276 entry->wiring_thread = curthread; 3277 next_entry = vm_map_entry_succ(entry); 3278 /* 3279 * Check the map for holes in the specified region. 3280 * If holes_ok, skip this check. 3281 */ 3282 if (!holes_ok && 3283 entry->end < end && next_entry->start > entry->end) { 3284 end = entry->end; 3285 rv = KERN_INVALID_ADDRESS; 3286 break; 3287 } 3288 /* 3289 * If system unwiring, require that the entry is system wired. 3290 */ 3291 if (!user_unwire && 3292 vm_map_entry_system_wired_count(entry) == 0) { 3293 end = entry->end; 3294 rv = KERN_INVALID_ARGUMENT; 3295 break; 3296 } 3297 } 3298 need_wakeup = false; 3299 if (first_entry == NULL && 3300 !vm_map_lookup_entry(map, start, &first_entry)) { 3301 KASSERT(holes_ok, ("vm_map_unwire: lookup failed")); 3302 prev_entry = first_entry; 3303 entry = vm_map_entry_succ(first_entry); 3304 } else { 3305 prev_entry = vm_map_entry_pred(first_entry); 3306 entry = first_entry; 3307 } 3308 for (; entry->start < end; 3309 prev_entry = entry, entry = vm_map_entry_succ(entry)) { 3310 /* 3311 * If holes_ok was specified, an empty 3312 * space in the unwired region could have been mapped 3313 * while the map lock was dropped for draining 3314 * MAP_ENTRY_IN_TRANSITION. Moreover, another thread 3315 * could be simultaneously wiring this new mapping 3316 * entry. Detect these cases and skip any entries 3317 * marked as in transition by us. 3318 */ 3319 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || 3320 entry->wiring_thread != curthread) { 3321 KASSERT(holes_ok, 3322 ("vm_map_unwire: !HOLESOK and new/changed entry")); 3323 continue; 3324 } 3325 3326 if (rv == KERN_SUCCESS && (!user_unwire || 3327 (entry->eflags & MAP_ENTRY_USER_WIRED))) { 3328 if (entry->wired_count == 1) 3329 vm_map_entry_unwire(map, entry); 3330 else 3331 entry->wired_count--; 3332 if (user_unwire) 3333 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3334 } 3335 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, 3336 ("vm_map_unwire: in-transition flag missing %p", entry)); 3337 KASSERT(entry->wiring_thread == curthread, 3338 ("vm_map_unwire: alien wire %p", entry)); 3339 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; 3340 entry->wiring_thread = NULL; 3341 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 3342 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 3343 need_wakeup = true; 3344 } 3345 vm_map_try_merge_entries(map, prev_entry, entry); 3346 } 3347 vm_map_try_merge_entries(map, prev_entry, entry); 3348 vm_map_unlock(map); 3349 if (need_wakeup) 3350 vm_map_wakeup(map); 3351 return (rv); 3352 } 3353 3354 static void 3355 vm_map_wire_user_count_sub(u_long npages) 3356 { 3357 3358 atomic_subtract_long(&vm_user_wire_count, npages); 3359 } 3360 3361 static bool 3362 vm_map_wire_user_count_add(u_long npages) 3363 { 3364 u_long wired; 3365 3366 wired = vm_user_wire_count; 3367 do { 3368 if (npages + wired > vm_page_max_user_wired) 3369 return (false); 3370 } while (!atomic_fcmpset_long(&vm_user_wire_count, &wired, 3371 npages + wired)); 3372 3373 return (true); 3374 } 3375 3376 /* 3377 * vm_map_wire_entry_failure: 3378 * 3379 * Handle a wiring failure on the given entry. 3380 * 3381 * The map should be locked. 3382 */ 3383 static void 3384 vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, 3385 vm_offset_t failed_addr) 3386 { 3387 3388 VM_MAP_ASSERT_LOCKED(map); 3389 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 && 3390 entry->wired_count == 1, 3391 ("vm_map_wire_entry_failure: entry %p isn't being wired", entry)); 3392 KASSERT(failed_addr < entry->end, 3393 ("vm_map_wire_entry_failure: entry %p was fully wired", entry)); 3394 3395 /* 3396 * If any pages at the start of this entry were successfully wired, 3397 * then unwire them. 3398 */ 3399 if (failed_addr > entry->start) { 3400 pmap_unwire(map->pmap, entry->start, failed_addr); 3401 vm_object_unwire(entry->object.vm_object, entry->offset, 3402 failed_addr - entry->start, PQ_ACTIVE); 3403 } 3404 3405 /* 3406 * Assign an out-of-range value to represent the failure to wire this 3407 * entry. 3408 */ 3409 entry->wired_count = -1; 3410 } 3411 3412 int 3413 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags) 3414 { 3415 int rv; 3416 3417 vm_map_lock(map); 3418 rv = vm_map_wire_locked(map, start, end, flags); 3419 vm_map_unlock(map); 3420 return (rv); 3421 } 3422 3423 /* 3424 * vm_map_wire_locked: 3425 * 3426 * Implements both kernel and user wiring. Returns with the map locked, 3427 * the map lock may be dropped. 3428 */ 3429 int 3430 vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags) 3431 { 3432 vm_map_entry_t entry, first_entry, next_entry, prev_entry; 3433 vm_offset_t faddr, saved_end, saved_start; 3434 u_long incr, npages; 3435 u_int bidx, last_timestamp; 3436 int rv; 3437 bool holes_ok, need_wakeup, user_wire; 3438 vm_prot_t prot; 3439 3440 VM_MAP_ASSERT_LOCKED(map); 3441 3442 if (start == end) 3443 return (KERN_SUCCESS); 3444 prot = 0; 3445 if (flags & VM_MAP_WIRE_WRITE) 3446 prot |= VM_PROT_WRITE; 3447 holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0; 3448 user_wire = (flags & VM_MAP_WIRE_USER) != 0; 3449 VM_MAP_RANGE_CHECK(map, start, end); 3450 if (!vm_map_lookup_entry(map, start, &first_entry)) { 3451 if (holes_ok) 3452 first_entry = vm_map_entry_succ(first_entry); 3453 else 3454 return (KERN_INVALID_ADDRESS); 3455 } 3456 for (entry = first_entry; entry->start < end; entry = next_entry) { 3457 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 3458 /* 3459 * We have not yet clipped the entry. 3460 */ 3461 next_entry = vm_map_entry_in_transition(map, start, 3462 &end, holes_ok, entry); 3463 if (next_entry == NULL) { 3464 if (entry == first_entry) 3465 return (KERN_INVALID_ADDRESS); 3466 rv = KERN_INVALID_ADDRESS; 3467 goto done; 3468 } 3469 first_entry = (entry == first_entry) ? 3470 next_entry : NULL; 3471 continue; 3472 } 3473 rv = vm_map_clip_start(map, entry, start); 3474 if (rv != KERN_SUCCESS) 3475 goto done; 3476 rv = vm_map_clip_end(map, entry, end); 3477 if (rv != KERN_SUCCESS) 3478 goto done; 3479 3480 /* 3481 * Mark the entry in case the map lock is released. (See 3482 * above.) 3483 */ 3484 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && 3485 entry->wiring_thread == NULL, 3486 ("owned map entry %p", entry)); 3487 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 3488 entry->wiring_thread = curthread; 3489 if ((entry->protection & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 3490 || (entry->protection & prot) != prot) { 3491 entry->eflags |= MAP_ENTRY_WIRE_SKIPPED; 3492 if (!holes_ok) { 3493 end = entry->end; 3494 rv = KERN_INVALID_ADDRESS; 3495 goto done; 3496 } 3497 } else if (entry->wired_count == 0) { 3498 entry->wired_count++; 3499 3500 npages = atop(entry->end - entry->start); 3501 if (user_wire && !vm_map_wire_user_count_add(npages)) { 3502 vm_map_wire_entry_failure(map, entry, 3503 entry->start); 3504 end = entry->end; 3505 rv = KERN_RESOURCE_SHORTAGE; 3506 goto done; 3507 } 3508 3509 /* 3510 * Release the map lock, relying on the in-transition 3511 * mark. Mark the map busy for fork. 3512 */ 3513 saved_start = entry->start; 3514 saved_end = entry->end; 3515 last_timestamp = map->timestamp; 3516 bidx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry); 3517 incr = pagesizes[bidx]; 3518 vm_map_busy(map); 3519 vm_map_unlock(map); 3520 3521 for (faddr = saved_start; faddr < saved_end; 3522 faddr += incr) { 3523 /* 3524 * Simulate a fault to get the page and enter 3525 * it into the physical map. 3526 */ 3527 rv = vm_fault(map, faddr, VM_PROT_NONE, 3528 VM_FAULT_WIRE, NULL); 3529 if (rv != KERN_SUCCESS) 3530 break; 3531 } 3532 vm_map_lock(map); 3533 vm_map_unbusy(map); 3534 if (last_timestamp + 1 != map->timestamp) { 3535 /* 3536 * Look again for the entry because the map was 3537 * modified while it was unlocked. The entry 3538 * may have been clipped, but NOT merged or 3539 * deleted. 3540 */ 3541 if (!vm_map_lookup_entry(map, saved_start, 3542 &next_entry)) 3543 KASSERT(false, 3544 ("vm_map_wire: lookup failed")); 3545 first_entry = (entry == first_entry) ? 3546 next_entry : NULL; 3547 for (entry = next_entry; entry->end < saved_end; 3548 entry = vm_map_entry_succ(entry)) { 3549 /* 3550 * In case of failure, handle entries 3551 * that were not fully wired here; 3552 * fully wired entries are handled 3553 * later. 3554 */ 3555 if (rv != KERN_SUCCESS && 3556 faddr < entry->end) 3557 vm_map_wire_entry_failure(map, 3558 entry, faddr); 3559 } 3560 } 3561 if (rv != KERN_SUCCESS) { 3562 vm_map_wire_entry_failure(map, entry, faddr); 3563 if (user_wire) 3564 vm_map_wire_user_count_sub(npages); 3565 end = entry->end; 3566 goto done; 3567 } 3568 } else if (!user_wire || 3569 (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 3570 entry->wired_count++; 3571 } 3572 /* 3573 * Check the map for holes in the specified region. 3574 * If holes_ok was specified, skip this check. 3575 */ 3576 next_entry = vm_map_entry_succ(entry); 3577 if (!holes_ok && 3578 entry->end < end && next_entry->start > entry->end) { 3579 end = entry->end; 3580 rv = KERN_INVALID_ADDRESS; 3581 goto done; 3582 } 3583 } 3584 rv = KERN_SUCCESS; 3585 done: 3586 need_wakeup = false; 3587 if (first_entry == NULL && 3588 !vm_map_lookup_entry(map, start, &first_entry)) { 3589 KASSERT(holes_ok, ("vm_map_wire: lookup failed")); 3590 prev_entry = first_entry; 3591 entry = vm_map_entry_succ(first_entry); 3592 } else { 3593 prev_entry = vm_map_entry_pred(first_entry); 3594 entry = first_entry; 3595 } 3596 for (; entry->start < end; 3597 prev_entry = entry, entry = vm_map_entry_succ(entry)) { 3598 /* 3599 * If holes_ok was specified, an empty 3600 * space in the unwired region could have been mapped 3601 * while the map lock was dropped for faulting in the 3602 * pages or draining MAP_ENTRY_IN_TRANSITION. 3603 * Moreover, another thread could be simultaneously 3604 * wiring this new mapping entry. Detect these cases 3605 * and skip any entries marked as in transition not by us. 3606 * 3607 * Another way to get an entry not marked with 3608 * MAP_ENTRY_IN_TRANSITION is after failed clipping, 3609 * which set rv to KERN_INVALID_ARGUMENT. 3610 */ 3611 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || 3612 entry->wiring_thread != curthread) { 3613 KASSERT(holes_ok || rv == KERN_INVALID_ARGUMENT, 3614 ("vm_map_wire: !HOLESOK and new/changed entry")); 3615 continue; 3616 } 3617 3618 if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0) { 3619 /* do nothing */ 3620 } else if (rv == KERN_SUCCESS) { 3621 if (user_wire) 3622 entry->eflags |= MAP_ENTRY_USER_WIRED; 3623 } else if (entry->wired_count == -1) { 3624 /* 3625 * Wiring failed on this entry. Thus, unwiring is 3626 * unnecessary. 3627 */ 3628 entry->wired_count = 0; 3629 } else if (!user_wire || 3630 (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 3631 /* 3632 * Undo the wiring. Wiring succeeded on this entry 3633 * but failed on a later entry. 3634 */ 3635 if (entry->wired_count == 1) { 3636 vm_map_entry_unwire(map, entry); 3637 if (user_wire) 3638 vm_map_wire_user_count_sub( 3639 atop(entry->end - entry->start)); 3640 } else 3641 entry->wired_count--; 3642 } 3643 KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, 3644 ("vm_map_wire: in-transition flag missing %p", entry)); 3645 KASSERT(entry->wiring_thread == curthread, 3646 ("vm_map_wire: alien wire %p", entry)); 3647 entry->eflags &= ~(MAP_ENTRY_IN_TRANSITION | 3648 MAP_ENTRY_WIRE_SKIPPED); 3649 entry->wiring_thread = NULL; 3650 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 3651 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 3652 need_wakeup = true; 3653 } 3654 vm_map_try_merge_entries(map, prev_entry, entry); 3655 } 3656 vm_map_try_merge_entries(map, prev_entry, entry); 3657 if (need_wakeup) 3658 vm_map_wakeup(map); 3659 return (rv); 3660 } 3661 3662 /* 3663 * vm_map_sync 3664 * 3665 * Push any dirty cached pages in the address range to their pager. 3666 * If syncio is TRUE, dirty pages are written synchronously. 3667 * If invalidate is TRUE, any cached pages are freed as well. 3668 * 3669 * If the size of the region from start to end is zero, we are 3670 * supposed to flush all modified pages within the region containing 3671 * start. Unfortunately, a region can be split or coalesced with 3672 * neighboring regions, making it difficult to determine what the 3673 * original region was. Therefore, we approximate this requirement by 3674 * flushing the current region containing start. 3675 * 3676 * Returns an error if any part of the specified range is not mapped. 3677 */ 3678 int 3679 vm_map_sync( 3680 vm_map_t map, 3681 vm_offset_t start, 3682 vm_offset_t end, 3683 boolean_t syncio, 3684 boolean_t invalidate) 3685 { 3686 vm_map_entry_t entry, first_entry, next_entry; 3687 vm_size_t size; 3688 vm_object_t object; 3689 vm_ooffset_t offset; 3690 unsigned int last_timestamp; 3691 int bdry_idx; 3692 boolean_t failed; 3693 3694 vm_map_lock_read(map); 3695 VM_MAP_RANGE_CHECK(map, start, end); 3696 if (!vm_map_lookup_entry(map, start, &first_entry)) { 3697 vm_map_unlock_read(map); 3698 return (KERN_INVALID_ADDRESS); 3699 } else if (start == end) { 3700 start = first_entry->start; 3701 end = first_entry->end; 3702 } 3703 3704 /* 3705 * Make a first pass to check for user-wired memory, holes, 3706 * and partial invalidation of largepage mappings. 3707 */ 3708 for (entry = first_entry; entry->start < end; entry = next_entry) { 3709 if (invalidate) { 3710 if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0) { 3711 vm_map_unlock_read(map); 3712 return (KERN_INVALID_ARGUMENT); 3713 } 3714 bdry_idx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry); 3715 if (bdry_idx != 0 && 3716 ((start & (pagesizes[bdry_idx] - 1)) != 0 || 3717 (end & (pagesizes[bdry_idx] - 1)) != 0)) { 3718 vm_map_unlock_read(map); 3719 return (KERN_INVALID_ARGUMENT); 3720 } 3721 } 3722 next_entry = vm_map_entry_succ(entry); 3723 if (end > entry->end && 3724 entry->end != next_entry->start) { 3725 vm_map_unlock_read(map); 3726 return (KERN_INVALID_ADDRESS); 3727 } 3728 } 3729 3730 if (invalidate) 3731 pmap_remove(map->pmap, start, end); 3732 failed = FALSE; 3733 3734 /* 3735 * Make a second pass, cleaning/uncaching pages from the indicated 3736 * objects as we go. 3737 */ 3738 for (entry = first_entry; entry->start < end;) { 3739 offset = entry->offset + (start - entry->start); 3740 size = (end <= entry->end ? end : entry->end) - start; 3741 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) { 3742 vm_map_t smap; 3743 vm_map_entry_t tentry; 3744 vm_size_t tsize; 3745 3746 smap = entry->object.sub_map; 3747 vm_map_lock_read(smap); 3748 (void) vm_map_lookup_entry(smap, offset, &tentry); 3749 tsize = tentry->end - offset; 3750 if (tsize < size) 3751 size = tsize; 3752 object = tentry->object.vm_object; 3753 offset = tentry->offset + (offset - tentry->start); 3754 vm_map_unlock_read(smap); 3755 } else { 3756 object = entry->object.vm_object; 3757 } 3758 vm_object_reference(object); 3759 last_timestamp = map->timestamp; 3760 vm_map_unlock_read(map); 3761 if (!vm_object_sync(object, offset, size, syncio, invalidate)) 3762 failed = TRUE; 3763 start += size; 3764 vm_object_deallocate(object); 3765 vm_map_lock_read(map); 3766 if (last_timestamp == map->timestamp || 3767 !vm_map_lookup_entry(map, start, &entry)) 3768 entry = vm_map_entry_succ(entry); 3769 } 3770 3771 vm_map_unlock_read(map); 3772 return (failed ? KERN_FAILURE : KERN_SUCCESS); 3773 } 3774 3775 /* 3776 * vm_map_entry_unwire: [ internal use only ] 3777 * 3778 * Make the region specified by this entry pageable. 3779 * 3780 * The map in question should be locked. 3781 * [This is the reason for this routine's existence.] 3782 */ 3783 static void 3784 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) 3785 { 3786 vm_size_t size; 3787 3788 VM_MAP_ASSERT_LOCKED(map); 3789 KASSERT(entry->wired_count > 0, 3790 ("vm_map_entry_unwire: entry %p isn't wired", entry)); 3791 3792 size = entry->end - entry->start; 3793 if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0) 3794 vm_map_wire_user_count_sub(atop(size)); 3795 pmap_unwire(map->pmap, entry->start, entry->end); 3796 vm_object_unwire(entry->object.vm_object, entry->offset, size, 3797 PQ_ACTIVE); 3798 entry->wired_count = 0; 3799 } 3800 3801 static void 3802 vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map) 3803 { 3804 3805 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) 3806 vm_object_deallocate(entry->object.vm_object); 3807 uma_zfree(system_map ? kmapentzone : mapentzone, entry); 3808 } 3809 3810 /* 3811 * vm_map_entry_delete: [ internal use only ] 3812 * 3813 * Deallocate the given entry from the target map. 3814 */ 3815 static void 3816 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry) 3817 { 3818 vm_object_t object; 3819 vm_pindex_t offidxstart, offidxend, size1; 3820 vm_size_t size; 3821 3822 vm_map_entry_unlink(map, entry, UNLINK_MERGE_NONE); 3823 object = entry->object.vm_object; 3824 3825 if ((entry->eflags & MAP_ENTRY_GUARD) != 0) { 3826 MPASS(entry->cred == NULL); 3827 MPASS((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0); 3828 MPASS(object == NULL); 3829 vm_map_entry_deallocate(entry, map->system_map); 3830 return; 3831 } 3832 3833 size = entry->end - entry->start; 3834 map->size -= size; 3835 3836 if (entry->cred != NULL) { 3837 swap_release_by_cred(size, entry->cred); 3838 crfree(entry->cred); 3839 } 3840 3841 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 || object == NULL) { 3842 entry->object.vm_object = NULL; 3843 } else if ((object->flags & OBJ_ANON) != 0 || 3844 object == kernel_object) { 3845 KASSERT(entry->cred == NULL || object->cred == NULL || 3846 (entry->eflags & MAP_ENTRY_NEEDS_COPY), 3847 ("OVERCOMMIT vm_map_entry_delete: both cred %p", entry)); 3848 offidxstart = OFF_TO_IDX(entry->offset); 3849 offidxend = offidxstart + atop(size); 3850 VM_OBJECT_WLOCK(object); 3851 if (object->ref_count != 1 && 3852 ((object->flags & OBJ_ONEMAPPING) != 0 || 3853 object == kernel_object)) { 3854 vm_object_collapse(object); 3855 3856 /* 3857 * The option OBJPR_NOTMAPPED can be passed here 3858 * because vm_map_delete() already performed 3859 * pmap_remove() on the only mapping to this range 3860 * of pages. 3861 */ 3862 vm_object_page_remove(object, offidxstart, offidxend, 3863 OBJPR_NOTMAPPED); 3864 if (offidxend >= object->size && 3865 offidxstart < object->size) { 3866 size1 = object->size; 3867 object->size = offidxstart; 3868 if (object->cred != NULL) { 3869 size1 -= object->size; 3870 KASSERT(object->charge >= ptoa(size1), 3871 ("object %p charge < 0", object)); 3872 swap_release_by_cred(ptoa(size1), 3873 object->cred); 3874 object->charge -= ptoa(size1); 3875 } 3876 } 3877 } 3878 VM_OBJECT_WUNLOCK(object); 3879 } 3880 if (map->system_map) 3881 vm_map_entry_deallocate(entry, TRUE); 3882 else { 3883 entry->defer_next = curthread->td_map_def_user; 3884 curthread->td_map_def_user = entry; 3885 } 3886 } 3887 3888 /* 3889 * vm_map_delete: [ internal use only ] 3890 * 3891 * Deallocates the given address range from the target 3892 * map. 3893 */ 3894 int 3895 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end) 3896 { 3897 vm_map_entry_t entry, next_entry, scratch_entry; 3898 int rv; 3899 3900 VM_MAP_ASSERT_LOCKED(map); 3901 3902 if (start == end) 3903 return (KERN_SUCCESS); 3904 3905 /* 3906 * Find the start of the region, and clip it. 3907 * Step through all entries in this region. 3908 */ 3909 rv = vm_map_lookup_clip_start(map, start, &entry, &scratch_entry); 3910 if (rv != KERN_SUCCESS) 3911 return (rv); 3912 for (; entry->start < end; entry = next_entry) { 3913 /* 3914 * Wait for wiring or unwiring of an entry to complete. 3915 * Also wait for any system wirings to disappear on 3916 * user maps. 3917 */ 3918 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 || 3919 (vm_map_pmap(map) != kernel_pmap && 3920 vm_map_entry_system_wired_count(entry) != 0)) { 3921 unsigned int last_timestamp; 3922 vm_offset_t saved_start; 3923 3924 saved_start = entry->start; 3925 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 3926 last_timestamp = map->timestamp; 3927 (void) vm_map_unlock_and_wait(map, 0); 3928 vm_map_lock(map); 3929 if (last_timestamp + 1 != map->timestamp) { 3930 /* 3931 * Look again for the entry because the map was 3932 * modified while it was unlocked. 3933 * Specifically, the entry may have been 3934 * clipped, merged, or deleted. 3935 */ 3936 rv = vm_map_lookup_clip_start(map, saved_start, 3937 &next_entry, &scratch_entry); 3938 if (rv != KERN_SUCCESS) 3939 break; 3940 } else 3941 next_entry = entry; 3942 continue; 3943 } 3944 3945 /* XXXKIB or delete to the upper superpage boundary ? */ 3946 rv = vm_map_clip_end(map, entry, end); 3947 if (rv != KERN_SUCCESS) 3948 break; 3949 next_entry = vm_map_entry_succ(entry); 3950 3951 /* 3952 * Unwire before removing addresses from the pmap; otherwise, 3953 * unwiring will put the entries back in the pmap. 3954 */ 3955 if (entry->wired_count != 0) 3956 vm_map_entry_unwire(map, entry); 3957 3958 /* 3959 * Remove mappings for the pages, but only if the 3960 * mappings could exist. For instance, it does not 3961 * make sense to call pmap_remove() for guard entries. 3962 */ 3963 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 || 3964 entry->object.vm_object != NULL) 3965 pmap_map_delete(map->pmap, entry->start, entry->end); 3966 3967 if (entry->end == map->anon_loc) 3968 map->anon_loc = entry->start; 3969 3970 /* 3971 * Delete the entry only after removing all pmap 3972 * entries pointing to its pages. (Otherwise, its 3973 * page frames may be reallocated, and any modify bits 3974 * will be set in the wrong object!) 3975 */ 3976 vm_map_entry_delete(map, entry); 3977 } 3978 return (rv); 3979 } 3980 3981 /* 3982 * vm_map_remove: 3983 * 3984 * Remove the given address range from the target map. 3985 * This is the exported form of vm_map_delete. 3986 */ 3987 int 3988 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) 3989 { 3990 int result; 3991 3992 vm_map_lock(map); 3993 VM_MAP_RANGE_CHECK(map, start, end); 3994 result = vm_map_delete(map, start, end); 3995 vm_map_unlock(map); 3996 return (result); 3997 } 3998 3999 /* 4000 * vm_map_check_protection: 4001 * 4002 * Assert that the target map allows the specified privilege on the 4003 * entire address region given. The entire region must be allocated. 4004 * 4005 * WARNING! This code does not and should not check whether the 4006 * contents of the region is accessible. For example a smaller file 4007 * might be mapped into a larger address space. 4008 * 4009 * NOTE! This code is also called by munmap(). 4010 * 4011 * The map must be locked. A read lock is sufficient. 4012 */ 4013 boolean_t 4014 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, 4015 vm_prot_t protection) 4016 { 4017 vm_map_entry_t entry; 4018 vm_map_entry_t tmp_entry; 4019 4020 if (!vm_map_lookup_entry(map, start, &tmp_entry)) 4021 return (FALSE); 4022 entry = tmp_entry; 4023 4024 while (start < end) { 4025 /* 4026 * No holes allowed! 4027 */ 4028 if (start < entry->start) 4029 return (FALSE); 4030 /* 4031 * Check protection associated with entry. 4032 */ 4033 if ((entry->protection & protection) != protection) 4034 return (FALSE); 4035 /* go to next entry */ 4036 start = entry->end; 4037 entry = vm_map_entry_succ(entry); 4038 } 4039 return (TRUE); 4040 } 4041 4042 /* 4043 * 4044 * vm_map_copy_swap_object: 4045 * 4046 * Copies a swap-backed object from an existing map entry to a 4047 * new one. Carries forward the swap charge. May change the 4048 * src object on return. 4049 */ 4050 static void 4051 vm_map_copy_swap_object(vm_map_entry_t src_entry, vm_map_entry_t dst_entry, 4052 vm_offset_t size, vm_ooffset_t *fork_charge) 4053 { 4054 vm_object_t src_object; 4055 struct ucred *cred; 4056 int charged; 4057 4058 src_object = src_entry->object.vm_object; 4059 charged = ENTRY_CHARGED(src_entry); 4060 if ((src_object->flags & OBJ_ANON) != 0) { 4061 VM_OBJECT_WLOCK(src_object); 4062 vm_object_collapse(src_object); 4063 if ((src_object->flags & OBJ_ONEMAPPING) != 0) { 4064 vm_object_split(src_entry); 4065 src_object = src_entry->object.vm_object; 4066 } 4067 vm_object_reference_locked(src_object); 4068 vm_object_clear_flag(src_object, OBJ_ONEMAPPING); 4069 VM_OBJECT_WUNLOCK(src_object); 4070 } else 4071 vm_object_reference(src_object); 4072 if (src_entry->cred != NULL && 4073 !(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { 4074 KASSERT(src_object->cred == NULL, 4075 ("OVERCOMMIT: vm_map_copy_anon_entry: cred %p", 4076 src_object)); 4077 src_object->cred = src_entry->cred; 4078 src_object->charge = size; 4079 } 4080 dst_entry->object.vm_object = src_object; 4081 if (charged) { 4082 cred = curthread->td_ucred; 4083 crhold(cred); 4084 dst_entry->cred = cred; 4085 *fork_charge += size; 4086 if (!(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { 4087 crhold(cred); 4088 src_entry->cred = cred; 4089 *fork_charge += size; 4090 } 4091 } 4092 } 4093 4094 /* 4095 * vm_map_copy_entry: 4096 * 4097 * Copies the contents of the source entry to the destination 4098 * entry. The entries *must* be aligned properly. 4099 */ 4100 static void 4101 vm_map_copy_entry( 4102 vm_map_t src_map, 4103 vm_map_t dst_map, 4104 vm_map_entry_t src_entry, 4105 vm_map_entry_t dst_entry, 4106 vm_ooffset_t *fork_charge) 4107 { 4108 vm_object_t src_object; 4109 vm_map_entry_t fake_entry; 4110 vm_offset_t size; 4111 4112 VM_MAP_ASSERT_LOCKED(dst_map); 4113 4114 if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP) 4115 return; 4116 4117 if (src_entry->wired_count == 0 || 4118 (src_entry->protection & VM_PROT_WRITE) == 0) { 4119 /* 4120 * If the source entry is marked needs_copy, it is already 4121 * write-protected. 4122 */ 4123 if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0 && 4124 (src_entry->protection & VM_PROT_WRITE) != 0) { 4125 pmap_protect(src_map->pmap, 4126 src_entry->start, 4127 src_entry->end, 4128 src_entry->protection & ~VM_PROT_WRITE); 4129 } 4130 4131 /* 4132 * Make a copy of the object. 4133 */ 4134 size = src_entry->end - src_entry->start; 4135 if ((src_object = src_entry->object.vm_object) != NULL) { 4136 if ((src_object->flags & OBJ_SWAP) != 0) { 4137 vm_map_copy_swap_object(src_entry, dst_entry, 4138 size, fork_charge); 4139 /* May have split/collapsed, reload obj. */ 4140 src_object = src_entry->object.vm_object; 4141 } else { 4142 vm_object_reference(src_object); 4143 dst_entry->object.vm_object = src_object; 4144 } 4145 src_entry->eflags |= MAP_ENTRY_COW | 4146 MAP_ENTRY_NEEDS_COPY; 4147 dst_entry->eflags |= MAP_ENTRY_COW | 4148 MAP_ENTRY_NEEDS_COPY; 4149 dst_entry->offset = src_entry->offset; 4150 if (src_entry->eflags & MAP_ENTRY_WRITECNT) { 4151 /* 4152 * MAP_ENTRY_WRITECNT cannot 4153 * indicate write reference from 4154 * src_entry, since the entry is 4155 * marked as needs copy. Allocate a 4156 * fake entry that is used to 4157 * decrement object->un_pager writecount 4158 * at the appropriate time. Attach 4159 * fake_entry to the deferred list. 4160 */ 4161 fake_entry = vm_map_entry_create(dst_map); 4162 fake_entry->eflags = MAP_ENTRY_WRITECNT; 4163 src_entry->eflags &= ~MAP_ENTRY_WRITECNT; 4164 vm_object_reference(src_object); 4165 fake_entry->object.vm_object = src_object; 4166 fake_entry->start = src_entry->start; 4167 fake_entry->end = src_entry->end; 4168 fake_entry->defer_next = 4169 curthread->td_map_def_user; 4170 curthread->td_map_def_user = fake_entry; 4171 } 4172 4173 pmap_copy(dst_map->pmap, src_map->pmap, 4174 dst_entry->start, dst_entry->end - dst_entry->start, 4175 src_entry->start); 4176 } else { 4177 dst_entry->object.vm_object = NULL; 4178 if ((dst_entry->eflags & MAP_ENTRY_GUARD) == 0) 4179 dst_entry->offset = 0; 4180 if (src_entry->cred != NULL) { 4181 dst_entry->cred = curthread->td_ucred; 4182 crhold(dst_entry->cred); 4183 *fork_charge += size; 4184 } 4185 } 4186 } else { 4187 /* 4188 * We don't want to make writeable wired pages copy-on-write. 4189 * Immediately copy these pages into the new map by simulating 4190 * page faults. The new pages are pageable. 4191 */ 4192 vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry, 4193 fork_charge); 4194 } 4195 } 4196 4197 /* 4198 * vmspace_map_entry_forked: 4199 * Update the newly-forked vmspace each time a map entry is inherited 4200 * or copied. The values for vm_dsize and vm_tsize are approximate 4201 * (and mostly-obsolete ideas in the face of mmap(2) et al.) 4202 */ 4203 static void 4204 vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2, 4205 vm_map_entry_t entry) 4206 { 4207 vm_size_t entrysize; 4208 vm_offset_t newend; 4209 4210 if ((entry->eflags & MAP_ENTRY_GUARD) != 0) 4211 return; 4212 entrysize = entry->end - entry->start; 4213 vm2->vm_map.size += entrysize; 4214 if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) { 4215 vm2->vm_ssize += btoc(entrysize); 4216 } else if (entry->start >= (vm_offset_t)vm1->vm_daddr && 4217 entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) { 4218 newend = MIN(entry->end, 4219 (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)); 4220 vm2->vm_dsize += btoc(newend - entry->start); 4221 } else if (entry->start >= (vm_offset_t)vm1->vm_taddr && 4222 entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) { 4223 newend = MIN(entry->end, 4224 (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)); 4225 vm2->vm_tsize += btoc(newend - entry->start); 4226 } 4227 } 4228 4229 /* 4230 * vmspace_fork: 4231 * Create a new process vmspace structure and vm_map 4232 * based on those of an existing process. The new map 4233 * is based on the old map, according to the inheritance 4234 * values on the regions in that map. 4235 * 4236 * XXX It might be worth coalescing the entries added to the new vmspace. 4237 * 4238 * The source map must not be locked. 4239 */ 4240 struct vmspace * 4241 vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge) 4242 { 4243 struct vmspace *vm2; 4244 vm_map_t new_map, old_map; 4245 vm_map_entry_t new_entry, old_entry; 4246 vm_object_t object; 4247 int error, locked __diagused; 4248 vm_inherit_t inh; 4249 4250 old_map = &vm1->vm_map; 4251 /* Copy immutable fields of vm1 to vm2. */ 4252 vm2 = vmspace_alloc(vm_map_min(old_map), vm_map_max(old_map), 4253 pmap_pinit); 4254 if (vm2 == NULL) 4255 return (NULL); 4256 4257 vm2->vm_taddr = vm1->vm_taddr; 4258 vm2->vm_daddr = vm1->vm_daddr; 4259 vm2->vm_maxsaddr = vm1->vm_maxsaddr; 4260 vm2->vm_stacktop = vm1->vm_stacktop; 4261 vm2->vm_shp_base = vm1->vm_shp_base; 4262 vm_map_lock(old_map); 4263 if (old_map->busy) 4264 vm_map_wait_busy(old_map); 4265 new_map = &vm2->vm_map; 4266 locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */ 4267 KASSERT(locked, ("vmspace_fork: lock failed")); 4268 4269 error = pmap_vmspace_copy(new_map->pmap, old_map->pmap); 4270 if (error != 0) { 4271 sx_xunlock(&old_map->lock); 4272 sx_xunlock(&new_map->lock); 4273 vm_map_process_deferred(); 4274 vmspace_free(vm2); 4275 return (NULL); 4276 } 4277 4278 new_map->anon_loc = old_map->anon_loc; 4279 new_map->flags |= old_map->flags & (MAP_ASLR | MAP_ASLR_IGNSTART | 4280 MAP_ASLR_STACK | MAP_WXORX); 4281 4282 VM_MAP_ENTRY_FOREACH(old_entry, old_map) { 4283 if ((old_entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) 4284 panic("vm_map_fork: encountered a submap"); 4285 4286 inh = old_entry->inheritance; 4287 if ((old_entry->eflags & MAP_ENTRY_GUARD) != 0 && 4288 inh != VM_INHERIT_NONE) 4289 inh = VM_INHERIT_COPY; 4290 4291 switch (inh) { 4292 case VM_INHERIT_NONE: 4293 break; 4294 4295 case VM_INHERIT_SHARE: 4296 /* 4297 * Clone the entry, creating the shared object if 4298 * necessary. 4299 */ 4300 object = old_entry->object.vm_object; 4301 if (object == NULL) { 4302 vm_map_entry_back(old_entry); 4303 object = old_entry->object.vm_object; 4304 } 4305 4306 /* 4307 * Add the reference before calling vm_object_shadow 4308 * to insure that a shadow object is created. 4309 */ 4310 vm_object_reference(object); 4311 if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { 4312 vm_object_shadow(&old_entry->object.vm_object, 4313 &old_entry->offset, 4314 old_entry->end - old_entry->start, 4315 old_entry->cred, 4316 /* Transfer the second reference too. */ 4317 true); 4318 old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 4319 old_entry->cred = NULL; 4320 4321 /* 4322 * As in vm_map_merged_neighbor_dispose(), 4323 * the vnode lock will not be acquired in 4324 * this call to vm_object_deallocate(). 4325 */ 4326 vm_object_deallocate(object); 4327 object = old_entry->object.vm_object; 4328 } else { 4329 VM_OBJECT_WLOCK(object); 4330 vm_object_clear_flag(object, OBJ_ONEMAPPING); 4331 if (old_entry->cred != NULL) { 4332 KASSERT(object->cred == NULL, 4333 ("vmspace_fork both cred")); 4334 object->cred = old_entry->cred; 4335 object->charge = old_entry->end - 4336 old_entry->start; 4337 old_entry->cred = NULL; 4338 } 4339 4340 /* 4341 * Assert the correct state of the vnode 4342 * v_writecount while the object is locked, to 4343 * not relock it later for the assertion 4344 * correctness. 4345 */ 4346 if (old_entry->eflags & MAP_ENTRY_WRITECNT && 4347 object->type == OBJT_VNODE) { 4348 KASSERT(((struct vnode *)object-> 4349 handle)->v_writecount > 0, 4350 ("vmspace_fork: v_writecount %p", 4351 object)); 4352 KASSERT(object->un_pager.vnp. 4353 writemappings > 0, 4354 ("vmspace_fork: vnp.writecount %p", 4355 object)); 4356 } 4357 VM_OBJECT_WUNLOCK(object); 4358 } 4359 4360 /* 4361 * Clone the entry, referencing the shared object. 4362 */ 4363 new_entry = vm_map_entry_create(new_map); 4364 *new_entry = *old_entry; 4365 new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | 4366 MAP_ENTRY_IN_TRANSITION); 4367 new_entry->wiring_thread = NULL; 4368 new_entry->wired_count = 0; 4369 if (new_entry->eflags & MAP_ENTRY_WRITECNT) { 4370 vm_pager_update_writecount(object, 4371 new_entry->start, new_entry->end); 4372 } 4373 vm_map_entry_set_vnode_text(new_entry, true); 4374 4375 /* 4376 * Insert the entry into the new map -- we know we're 4377 * inserting at the end of the new map. 4378 */ 4379 vm_map_entry_link(new_map, new_entry); 4380 vmspace_map_entry_forked(vm1, vm2, new_entry); 4381 4382 /* 4383 * Update the physical map 4384 */ 4385 pmap_copy(new_map->pmap, old_map->pmap, 4386 new_entry->start, 4387 (old_entry->end - old_entry->start), 4388 old_entry->start); 4389 break; 4390 4391 case VM_INHERIT_COPY: 4392 /* 4393 * Clone the entry and link into the map. 4394 */ 4395 new_entry = vm_map_entry_create(new_map); 4396 *new_entry = *old_entry; 4397 /* 4398 * Copied entry is COW over the old object. 4399 */ 4400 new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | 4401 MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_WRITECNT); 4402 new_entry->wiring_thread = NULL; 4403 new_entry->wired_count = 0; 4404 new_entry->object.vm_object = NULL; 4405 new_entry->cred = NULL; 4406 vm_map_entry_link(new_map, new_entry); 4407 vmspace_map_entry_forked(vm1, vm2, new_entry); 4408 vm_map_copy_entry(old_map, new_map, old_entry, 4409 new_entry, fork_charge); 4410 vm_map_entry_set_vnode_text(new_entry, true); 4411 break; 4412 4413 case VM_INHERIT_ZERO: 4414 /* 4415 * Create a new anonymous mapping entry modelled from 4416 * the old one. 4417 */ 4418 new_entry = vm_map_entry_create(new_map); 4419 memset(new_entry, 0, sizeof(*new_entry)); 4420 4421 new_entry->start = old_entry->start; 4422 new_entry->end = old_entry->end; 4423 new_entry->eflags = old_entry->eflags & 4424 ~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION | 4425 MAP_ENTRY_WRITECNT | MAP_ENTRY_VN_EXEC | 4426 MAP_ENTRY_SPLIT_BOUNDARY_MASK); 4427 new_entry->protection = old_entry->protection; 4428 new_entry->max_protection = old_entry->max_protection; 4429 new_entry->inheritance = VM_INHERIT_ZERO; 4430 4431 vm_map_entry_link(new_map, new_entry); 4432 vmspace_map_entry_forked(vm1, vm2, new_entry); 4433 4434 new_entry->cred = curthread->td_ucred; 4435 crhold(new_entry->cred); 4436 *fork_charge += (new_entry->end - new_entry->start); 4437 4438 break; 4439 } 4440 } 4441 /* 4442 * Use inlined vm_map_unlock() to postpone handling the deferred 4443 * map entries, which cannot be done until both old_map and 4444 * new_map locks are released. 4445 */ 4446 sx_xunlock(&old_map->lock); 4447 sx_xunlock(&new_map->lock); 4448 vm_map_process_deferred(); 4449 4450 return (vm2); 4451 } 4452 4453 /* 4454 * Create a process's stack for exec_new_vmspace(). This function is never 4455 * asked to wire the newly created stack. 4456 */ 4457 int 4458 vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, 4459 vm_prot_t prot, vm_prot_t max, int cow) 4460 { 4461 vm_size_t growsize, init_ssize; 4462 rlim_t vmemlim; 4463 int rv; 4464 4465 MPASS((map->flags & MAP_WIREFUTURE) == 0); 4466 growsize = sgrowsiz; 4467 init_ssize = (max_ssize < growsize) ? max_ssize : growsize; 4468 vm_map_lock(map); 4469 vmemlim = lim_cur(curthread, RLIMIT_VMEM); 4470 /* If we would blow our VMEM resource limit, no go */ 4471 if (map->size + init_ssize > vmemlim) { 4472 rv = KERN_NO_SPACE; 4473 goto out; 4474 } 4475 rv = vm_map_stack_locked(map, addrbos, max_ssize, growsize, prot, 4476 max, cow); 4477 out: 4478 vm_map_unlock(map); 4479 return (rv); 4480 } 4481 4482 static int stack_guard_page = 1; 4483 SYSCTL_INT(_security_bsd, OID_AUTO, stack_guard_page, CTLFLAG_RWTUN, 4484 &stack_guard_page, 0, 4485 "Specifies the number of guard pages for a stack that grows"); 4486 4487 static int 4488 vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, 4489 vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow) 4490 { 4491 vm_map_entry_t gap_entry, new_entry, prev_entry; 4492 vm_offset_t bot, gap_bot, gap_top, top; 4493 vm_size_t init_ssize, sgp; 4494 int orient, rv; 4495 4496 /* 4497 * The stack orientation is piggybacked with the cow argument. 4498 * Extract it into orient and mask the cow argument so that we 4499 * don't pass it around further. 4500 */ 4501 orient = cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP); 4502 KASSERT(orient != 0, ("No stack grow direction")); 4503 KASSERT(orient != (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP), 4504 ("bi-dir stack")); 4505 4506 if (max_ssize == 0 || 4507 !vm_map_range_valid(map, addrbos, addrbos + max_ssize)) 4508 return (KERN_INVALID_ADDRESS); 4509 sgp = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 || 4510 (curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 : 4511 (vm_size_t)stack_guard_page * PAGE_SIZE; 4512 if (sgp >= max_ssize) 4513 return (KERN_INVALID_ARGUMENT); 4514 4515 init_ssize = growsize; 4516 if (max_ssize < init_ssize + sgp) 4517 init_ssize = max_ssize - sgp; 4518 4519 /* If addr is already mapped, no go */ 4520 if (vm_map_lookup_entry(map, addrbos, &prev_entry)) 4521 return (KERN_NO_SPACE); 4522 4523 /* 4524 * If we can't accommodate max_ssize in the current mapping, no go. 4525 */ 4526 if (vm_map_entry_succ(prev_entry)->start < addrbos + max_ssize) 4527 return (KERN_NO_SPACE); 4528 4529 /* 4530 * We initially map a stack of only init_ssize. We will grow as 4531 * needed later. Depending on the orientation of the stack (i.e. 4532 * the grow direction) we either map at the top of the range, the 4533 * bottom of the range or in the middle. 4534 * 4535 * Note: we would normally expect prot and max to be VM_PROT_ALL, 4536 * and cow to be 0. Possibly we should eliminate these as input 4537 * parameters, and just pass these values here in the insert call. 4538 */ 4539 if (orient == MAP_STACK_GROWS_DOWN) { 4540 bot = addrbos + max_ssize - init_ssize; 4541 top = bot + init_ssize; 4542 gap_bot = addrbos; 4543 gap_top = bot; 4544 } else /* if (orient == MAP_STACK_GROWS_UP) */ { 4545 bot = addrbos; 4546 top = bot + init_ssize; 4547 gap_bot = top; 4548 gap_top = addrbos + max_ssize; 4549 } 4550 rv = vm_map_insert(map, NULL, 0, bot, top, prot, max, cow); 4551 if (rv != KERN_SUCCESS) 4552 return (rv); 4553 new_entry = vm_map_entry_succ(prev_entry); 4554 KASSERT(new_entry->end == top || new_entry->start == bot, 4555 ("Bad entry start/end for new stack entry")); 4556 KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 || 4557 (new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0, 4558 ("new entry lacks MAP_ENTRY_GROWS_DOWN")); 4559 KASSERT((orient & MAP_STACK_GROWS_UP) == 0 || 4560 (new_entry->eflags & MAP_ENTRY_GROWS_UP) != 0, 4561 ("new entry lacks MAP_ENTRY_GROWS_UP")); 4562 if (gap_bot == gap_top) 4563 return (KERN_SUCCESS); 4564 rv = vm_map_insert(map, NULL, 0, gap_bot, gap_top, VM_PROT_NONE, 4565 VM_PROT_NONE, MAP_CREATE_GUARD | (orient == MAP_STACK_GROWS_DOWN ? 4566 MAP_CREATE_STACK_GAP_DN : MAP_CREATE_STACK_GAP_UP)); 4567 if (rv == KERN_SUCCESS) { 4568 /* 4569 * Gap can never successfully handle a fault, so 4570 * read-ahead logic is never used for it. Re-use 4571 * next_read of the gap entry to store 4572 * stack_guard_page for vm_map_growstack(). 4573 * Similarly, since a gap cannot have a backing object, 4574 * store the original stack protections in the 4575 * object offset. 4576 */ 4577 gap_entry = orient == MAP_STACK_GROWS_DOWN ? 4578 vm_map_entry_pred(new_entry) : vm_map_entry_succ(new_entry); 4579 gap_entry->next_read = sgp; 4580 gap_entry->offset = prot; 4581 } else { 4582 (void)vm_map_delete(map, bot, top); 4583 } 4584 return (rv); 4585 } 4586 4587 /* 4588 * Attempts to grow a vm stack entry. Returns KERN_SUCCESS if we 4589 * successfully grow the stack. 4590 */ 4591 static int 4592 vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry) 4593 { 4594 vm_map_entry_t stack_entry; 4595 struct proc *p; 4596 struct vmspace *vm; 4597 struct ucred *cred; 4598 vm_offset_t gap_end, gap_start, grow_start; 4599 vm_size_t grow_amount, guard, max_grow; 4600 vm_prot_t prot; 4601 rlim_t lmemlim, stacklim, vmemlim; 4602 int rv, rv1 __diagused; 4603 bool gap_deleted, grow_down, is_procstack; 4604 #ifdef notyet 4605 uint64_t limit; 4606 #endif 4607 #ifdef RACCT 4608 int error __diagused; 4609 #endif 4610 4611 p = curproc; 4612 vm = p->p_vmspace; 4613 4614 /* 4615 * Disallow stack growth when the access is performed by a 4616 * debugger or AIO daemon. The reason is that the wrong 4617 * resource limits are applied. 4618 */ 4619 if (p != initproc && (map != &p->p_vmspace->vm_map || 4620 p->p_textvp == NULL)) 4621 return (KERN_FAILURE); 4622 4623 MPASS(!map->system_map); 4624 4625 lmemlim = lim_cur(curthread, RLIMIT_MEMLOCK); 4626 stacklim = lim_cur(curthread, RLIMIT_STACK); 4627 vmemlim = lim_cur(curthread, RLIMIT_VMEM); 4628 retry: 4629 /* If addr is not in a hole for a stack grow area, no need to grow. */ 4630 if (gap_entry == NULL && !vm_map_lookup_entry(map, addr, &gap_entry)) 4631 return (KERN_FAILURE); 4632 if ((gap_entry->eflags & MAP_ENTRY_GUARD) == 0) 4633 return (KERN_SUCCESS); 4634 if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_DN) != 0) { 4635 stack_entry = vm_map_entry_succ(gap_entry); 4636 if ((stack_entry->eflags & MAP_ENTRY_GROWS_DOWN) == 0 || 4637 stack_entry->start != gap_entry->end) 4638 return (KERN_FAILURE); 4639 grow_amount = round_page(stack_entry->start - addr); 4640 grow_down = true; 4641 } else if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_UP) != 0) { 4642 stack_entry = vm_map_entry_pred(gap_entry); 4643 if ((stack_entry->eflags & MAP_ENTRY_GROWS_UP) == 0 || 4644 stack_entry->end != gap_entry->start) 4645 return (KERN_FAILURE); 4646 grow_amount = round_page(addr + 1 - stack_entry->end); 4647 grow_down = false; 4648 } else { 4649 return (KERN_FAILURE); 4650 } 4651 guard = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 || 4652 (curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 : 4653 gap_entry->next_read; 4654 max_grow = gap_entry->end - gap_entry->start; 4655 if (guard > max_grow) 4656 return (KERN_NO_SPACE); 4657 max_grow -= guard; 4658 if (grow_amount > max_grow) 4659 return (KERN_NO_SPACE); 4660 4661 /* 4662 * If this is the main process stack, see if we're over the stack 4663 * limit. 4664 */ 4665 is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr && 4666 addr < (vm_offset_t)vm->vm_stacktop; 4667 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) 4668 return (KERN_NO_SPACE); 4669 4670 #ifdef RACCT 4671 if (racct_enable) { 4672 PROC_LOCK(p); 4673 if (is_procstack && racct_set(p, RACCT_STACK, 4674 ctob(vm->vm_ssize) + grow_amount)) { 4675 PROC_UNLOCK(p); 4676 return (KERN_NO_SPACE); 4677 } 4678 PROC_UNLOCK(p); 4679 } 4680 #endif 4681 4682 grow_amount = roundup(grow_amount, sgrowsiz); 4683 if (grow_amount > max_grow) 4684 grow_amount = max_grow; 4685 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) { 4686 grow_amount = trunc_page((vm_size_t)stacklim) - 4687 ctob(vm->vm_ssize); 4688 } 4689 4690 #ifdef notyet 4691 PROC_LOCK(p); 4692 limit = racct_get_available(p, RACCT_STACK); 4693 PROC_UNLOCK(p); 4694 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > limit)) 4695 grow_amount = limit - ctob(vm->vm_ssize); 4696 #endif 4697 4698 if (!old_mlock && (map->flags & MAP_WIREFUTURE) != 0) { 4699 if (ptoa(pmap_wired_count(map->pmap)) + grow_amount > lmemlim) { 4700 rv = KERN_NO_SPACE; 4701 goto out; 4702 } 4703 #ifdef RACCT 4704 if (racct_enable) { 4705 PROC_LOCK(p); 4706 if (racct_set(p, RACCT_MEMLOCK, 4707 ptoa(pmap_wired_count(map->pmap)) + grow_amount)) { 4708 PROC_UNLOCK(p); 4709 rv = KERN_NO_SPACE; 4710 goto out; 4711 } 4712 PROC_UNLOCK(p); 4713 } 4714 #endif 4715 } 4716 4717 /* If we would blow our VMEM resource limit, no go */ 4718 if (map->size + grow_amount > vmemlim) { 4719 rv = KERN_NO_SPACE; 4720 goto out; 4721 } 4722 #ifdef RACCT 4723 if (racct_enable) { 4724 PROC_LOCK(p); 4725 if (racct_set(p, RACCT_VMEM, map->size + grow_amount)) { 4726 PROC_UNLOCK(p); 4727 rv = KERN_NO_SPACE; 4728 goto out; 4729 } 4730 PROC_UNLOCK(p); 4731 } 4732 #endif 4733 4734 if (vm_map_lock_upgrade(map)) { 4735 gap_entry = NULL; 4736 vm_map_lock_read(map); 4737 goto retry; 4738 } 4739 4740 if (grow_down) { 4741 /* 4742 * The gap_entry "offset" field is overloaded. See 4743 * vm_map_stack_locked(). 4744 */ 4745 prot = gap_entry->offset; 4746 4747 grow_start = gap_entry->end - grow_amount; 4748 if (gap_entry->start + grow_amount == gap_entry->end) { 4749 gap_start = gap_entry->start; 4750 gap_end = gap_entry->end; 4751 vm_map_entry_delete(map, gap_entry); 4752 gap_deleted = true; 4753 } else { 4754 MPASS(gap_entry->start < gap_entry->end - grow_amount); 4755 vm_map_entry_resize(map, gap_entry, -grow_amount); 4756 gap_deleted = false; 4757 } 4758 rv = vm_map_insert(map, NULL, 0, grow_start, 4759 grow_start + grow_amount, prot, prot, MAP_STACK_GROWS_DOWN); 4760 if (rv != KERN_SUCCESS) { 4761 if (gap_deleted) { 4762 rv1 = vm_map_insert(map, NULL, 0, gap_start, 4763 gap_end, VM_PROT_NONE, VM_PROT_NONE, 4764 MAP_CREATE_GUARD | MAP_CREATE_STACK_GAP_DN); 4765 MPASS(rv1 == KERN_SUCCESS); 4766 } else 4767 vm_map_entry_resize(map, gap_entry, 4768 grow_amount); 4769 } 4770 } else { 4771 grow_start = stack_entry->end; 4772 cred = stack_entry->cred; 4773 if (cred == NULL && stack_entry->object.vm_object != NULL) 4774 cred = stack_entry->object.vm_object->cred; 4775 if (cred != NULL && !swap_reserve_by_cred(grow_amount, cred)) 4776 rv = KERN_NO_SPACE; 4777 /* Grow the underlying object if applicable. */ 4778 else if (stack_entry->object.vm_object == NULL || 4779 vm_object_coalesce(stack_entry->object.vm_object, 4780 stack_entry->offset, 4781 (vm_size_t)(stack_entry->end - stack_entry->start), 4782 grow_amount, cred != NULL)) { 4783 if (gap_entry->start + grow_amount == gap_entry->end) { 4784 vm_map_entry_delete(map, gap_entry); 4785 vm_map_entry_resize(map, stack_entry, 4786 grow_amount); 4787 } else { 4788 gap_entry->start += grow_amount; 4789 stack_entry->end += grow_amount; 4790 } 4791 map->size += grow_amount; 4792 rv = KERN_SUCCESS; 4793 } else 4794 rv = KERN_FAILURE; 4795 } 4796 if (rv == KERN_SUCCESS && is_procstack) 4797 vm->vm_ssize += btoc(grow_amount); 4798 4799 /* 4800 * Heed the MAP_WIREFUTURE flag if it was set for this process. 4801 */ 4802 if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE) != 0) { 4803 rv = vm_map_wire_locked(map, grow_start, 4804 grow_start + grow_amount, 4805 VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES); 4806 } 4807 vm_map_lock_downgrade(map); 4808 4809 out: 4810 #ifdef RACCT 4811 if (racct_enable && rv != KERN_SUCCESS) { 4812 PROC_LOCK(p); 4813 error = racct_set(p, RACCT_VMEM, map->size); 4814 KASSERT(error == 0, ("decreasing RACCT_VMEM failed")); 4815 if (!old_mlock) { 4816 error = racct_set(p, RACCT_MEMLOCK, 4817 ptoa(pmap_wired_count(map->pmap))); 4818 KASSERT(error == 0, ("decreasing RACCT_MEMLOCK failed")); 4819 } 4820 error = racct_set(p, RACCT_STACK, ctob(vm->vm_ssize)); 4821 KASSERT(error == 0, ("decreasing RACCT_STACK failed")); 4822 PROC_UNLOCK(p); 4823 } 4824 #endif 4825 4826 return (rv); 4827 } 4828 4829 /* 4830 * Unshare the specified VM space for exec. If other processes are 4831 * mapped to it, then create a new one. The new vmspace is null. 4832 */ 4833 int 4834 vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser) 4835 { 4836 struct vmspace *oldvmspace = p->p_vmspace; 4837 struct vmspace *newvmspace; 4838 4839 KASSERT((curthread->td_pflags & TDP_EXECVMSPC) == 0, 4840 ("vmspace_exec recursed")); 4841 newvmspace = vmspace_alloc(minuser, maxuser, pmap_pinit); 4842 if (newvmspace == NULL) 4843 return (ENOMEM); 4844 newvmspace->vm_swrss = oldvmspace->vm_swrss; 4845 /* 4846 * This code is written like this for prototype purposes. The 4847 * goal is to avoid running down the vmspace here, but let the 4848 * other process's that are still using the vmspace to finally 4849 * run it down. Even though there is little or no chance of blocking 4850 * here, it is a good idea to keep this form for future mods. 4851 */ 4852 PROC_VMSPACE_LOCK(p); 4853 p->p_vmspace = newvmspace; 4854 PROC_VMSPACE_UNLOCK(p); 4855 if (p == curthread->td_proc) 4856 pmap_activate(curthread); 4857 curthread->td_pflags |= TDP_EXECVMSPC; 4858 return (0); 4859 } 4860 4861 /* 4862 * Unshare the specified VM space for forcing COW. This 4863 * is called by rfork, for the (RFMEM|RFPROC) == 0 case. 4864 */ 4865 int 4866 vmspace_unshare(struct proc *p) 4867 { 4868 struct vmspace *oldvmspace = p->p_vmspace; 4869 struct vmspace *newvmspace; 4870 vm_ooffset_t fork_charge; 4871 4872 /* 4873 * The caller is responsible for ensuring that the reference count 4874 * cannot concurrently transition 1 -> 2. 4875 */ 4876 if (refcount_load(&oldvmspace->vm_refcnt) == 1) 4877 return (0); 4878 fork_charge = 0; 4879 newvmspace = vmspace_fork(oldvmspace, &fork_charge); 4880 if (newvmspace == NULL) 4881 return (ENOMEM); 4882 if (!swap_reserve_by_cred(fork_charge, p->p_ucred)) { 4883 vmspace_free(newvmspace); 4884 return (ENOMEM); 4885 } 4886 PROC_VMSPACE_LOCK(p); 4887 p->p_vmspace = newvmspace; 4888 PROC_VMSPACE_UNLOCK(p); 4889 if (p == curthread->td_proc) 4890 pmap_activate(curthread); 4891 vmspace_free(oldvmspace); 4892 return (0); 4893 } 4894 4895 /* 4896 * vm_map_lookup: 4897 * 4898 * Finds the VM object, offset, and 4899 * protection for a given virtual address in the 4900 * specified map, assuming a page fault of the 4901 * type specified. 4902 * 4903 * Leaves the map in question locked for read; return 4904 * values are guaranteed until a vm_map_lookup_done 4905 * call is performed. Note that the map argument 4906 * is in/out; the returned map must be used in 4907 * the call to vm_map_lookup_done. 4908 * 4909 * A handle (out_entry) is returned for use in 4910 * vm_map_lookup_done, to make that fast. 4911 * 4912 * If a lookup is requested with "write protection" 4913 * specified, the map may be changed to perform virtual 4914 * copying operations, although the data referenced will 4915 * remain the same. 4916 */ 4917 int 4918 vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ 4919 vm_offset_t vaddr, 4920 vm_prot_t fault_typea, 4921 vm_map_entry_t *out_entry, /* OUT */ 4922 vm_object_t *object, /* OUT */ 4923 vm_pindex_t *pindex, /* OUT */ 4924 vm_prot_t *out_prot, /* OUT */ 4925 boolean_t *wired) /* OUT */ 4926 { 4927 vm_map_entry_t entry; 4928 vm_map_t map = *var_map; 4929 vm_prot_t prot; 4930 vm_prot_t fault_type; 4931 vm_object_t eobject; 4932 vm_size_t size; 4933 struct ucred *cred; 4934 4935 RetryLookup: 4936 4937 vm_map_lock_read(map); 4938 4939 RetryLookupLocked: 4940 /* 4941 * Lookup the faulting address. 4942 */ 4943 if (!vm_map_lookup_entry(map, vaddr, out_entry)) { 4944 vm_map_unlock_read(map); 4945 return (KERN_INVALID_ADDRESS); 4946 } 4947 4948 entry = *out_entry; 4949 4950 /* 4951 * Handle submaps. 4952 */ 4953 if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 4954 vm_map_t old_map = map; 4955 4956 *var_map = map = entry->object.sub_map; 4957 vm_map_unlock_read(old_map); 4958 goto RetryLookup; 4959 } 4960 4961 /* 4962 * Check whether this task is allowed to have this page. 4963 */ 4964 prot = entry->protection; 4965 if ((fault_typea & VM_PROT_FAULT_LOOKUP) != 0) { 4966 fault_typea &= ~VM_PROT_FAULT_LOOKUP; 4967 if (prot == VM_PROT_NONE && map != kernel_map && 4968 (entry->eflags & MAP_ENTRY_GUARD) != 0 && 4969 (entry->eflags & (MAP_ENTRY_STACK_GAP_DN | 4970 MAP_ENTRY_STACK_GAP_UP)) != 0 && 4971 vm_map_growstack(map, vaddr, entry) == KERN_SUCCESS) 4972 goto RetryLookupLocked; 4973 } 4974 fault_type = fault_typea & VM_PROT_ALL; 4975 if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) { 4976 vm_map_unlock_read(map); 4977 return (KERN_PROTECTION_FAILURE); 4978 } 4979 KASSERT((prot & VM_PROT_WRITE) == 0 || (entry->eflags & 4980 (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY)) != 4981 (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY), 4982 ("entry %p flags %x", entry, entry->eflags)); 4983 if ((fault_typea & VM_PROT_COPY) != 0 && 4984 (entry->max_protection & VM_PROT_WRITE) == 0 && 4985 (entry->eflags & MAP_ENTRY_COW) == 0) { 4986 vm_map_unlock_read(map); 4987 return (KERN_PROTECTION_FAILURE); 4988 } 4989 4990 /* 4991 * If this page is not pageable, we have to get it for all possible 4992 * accesses. 4993 */ 4994 *wired = (entry->wired_count != 0); 4995 if (*wired) 4996 fault_type = entry->protection; 4997 size = entry->end - entry->start; 4998 4999 /* 5000 * If the entry was copy-on-write, we either ... 5001 */ 5002 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 5003 /* 5004 * If we want to write the page, we may as well handle that 5005 * now since we've got the map locked. 5006 * 5007 * If we don't need to write the page, we just demote the 5008 * permissions allowed. 5009 */ 5010 if ((fault_type & VM_PROT_WRITE) != 0 || 5011 (fault_typea & VM_PROT_COPY) != 0) { 5012 /* 5013 * Make a new object, and place it in the object 5014 * chain. Note that no new references have appeared 5015 * -- one just moved from the map to the new 5016 * object. 5017 */ 5018 if (vm_map_lock_upgrade(map)) 5019 goto RetryLookup; 5020 5021 if (entry->cred == NULL) { 5022 /* 5023 * The debugger owner is charged for 5024 * the memory. 5025 */ 5026 cred = curthread->td_ucred; 5027 crhold(cred); 5028 if (!swap_reserve_by_cred(size, cred)) { 5029 crfree(cred); 5030 vm_map_unlock(map); 5031 return (KERN_RESOURCE_SHORTAGE); 5032 } 5033 entry->cred = cred; 5034 } 5035 eobject = entry->object.vm_object; 5036 vm_object_shadow(&entry->object.vm_object, 5037 &entry->offset, size, entry->cred, false); 5038 if (eobject == entry->object.vm_object) { 5039 /* 5040 * The object was not shadowed. 5041 */ 5042 swap_release_by_cred(size, entry->cred); 5043 crfree(entry->cred); 5044 } 5045 entry->cred = NULL; 5046 entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 5047 5048 vm_map_lock_downgrade(map); 5049 } else { 5050 /* 5051 * We're attempting to read a copy-on-write page -- 5052 * don't allow writes. 5053 */ 5054 prot &= ~VM_PROT_WRITE; 5055 } 5056 } 5057 5058 /* 5059 * Create an object if necessary. 5060 */ 5061 if (entry->object.vm_object == NULL && !map->system_map) { 5062 if (vm_map_lock_upgrade(map)) 5063 goto RetryLookup; 5064 entry->object.vm_object = vm_object_allocate_anon(atop(size), 5065 NULL, entry->cred, size); 5066 entry->offset = 0; 5067 entry->cred = NULL; 5068 vm_map_lock_downgrade(map); 5069 } 5070 5071 /* 5072 * Return the object/offset from this entry. If the entry was 5073 * copy-on-write or empty, it has been fixed up. 5074 */ 5075 *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); 5076 *object = entry->object.vm_object; 5077 5078 *out_prot = prot; 5079 return (KERN_SUCCESS); 5080 } 5081 5082 /* 5083 * vm_map_lookup_locked: 5084 * 5085 * Lookup the faulting address. A version of vm_map_lookup that returns 5086 * KERN_FAILURE instead of blocking on map lock or memory allocation. 5087 */ 5088 int 5089 vm_map_lookup_locked(vm_map_t *var_map, /* IN/OUT */ 5090 vm_offset_t vaddr, 5091 vm_prot_t fault_typea, 5092 vm_map_entry_t *out_entry, /* OUT */ 5093 vm_object_t *object, /* OUT */ 5094 vm_pindex_t *pindex, /* OUT */ 5095 vm_prot_t *out_prot, /* OUT */ 5096 boolean_t *wired) /* OUT */ 5097 { 5098 vm_map_entry_t entry; 5099 vm_map_t map = *var_map; 5100 vm_prot_t prot; 5101 vm_prot_t fault_type = fault_typea; 5102 5103 /* 5104 * Lookup the faulting address. 5105 */ 5106 if (!vm_map_lookup_entry(map, vaddr, out_entry)) 5107 return (KERN_INVALID_ADDRESS); 5108 5109 entry = *out_entry; 5110 5111 /* 5112 * Fail if the entry refers to a submap. 5113 */ 5114 if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) 5115 return (KERN_FAILURE); 5116 5117 /* 5118 * Check whether this task is allowed to have this page. 5119 */ 5120 prot = entry->protection; 5121 fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE; 5122 if ((fault_type & prot) != fault_type) 5123 return (KERN_PROTECTION_FAILURE); 5124 5125 /* 5126 * If this page is not pageable, we have to get it for all possible 5127 * accesses. 5128 */ 5129 *wired = (entry->wired_count != 0); 5130 if (*wired) 5131 fault_type = entry->protection; 5132 5133 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 5134 /* 5135 * Fail if the entry was copy-on-write for a write fault. 5136 */ 5137 if (fault_type & VM_PROT_WRITE) 5138 return (KERN_FAILURE); 5139 /* 5140 * We're attempting to read a copy-on-write page -- 5141 * don't allow writes. 5142 */ 5143 prot &= ~VM_PROT_WRITE; 5144 } 5145 5146 /* 5147 * Fail if an object should be created. 5148 */ 5149 if (entry->object.vm_object == NULL && !map->system_map) 5150 return (KERN_FAILURE); 5151 5152 /* 5153 * Return the object/offset from this entry. If the entry was 5154 * copy-on-write or empty, it has been fixed up. 5155 */ 5156 *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); 5157 *object = entry->object.vm_object; 5158 5159 *out_prot = prot; 5160 return (KERN_SUCCESS); 5161 } 5162 5163 /* 5164 * vm_map_lookup_done: 5165 * 5166 * Releases locks acquired by a vm_map_lookup 5167 * (according to the handle returned by that lookup). 5168 */ 5169 void 5170 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry) 5171 { 5172 /* 5173 * Unlock the main-level map 5174 */ 5175 vm_map_unlock_read(map); 5176 } 5177 5178 vm_offset_t 5179 vm_map_max_KBI(const struct vm_map *map) 5180 { 5181 5182 return (vm_map_max(map)); 5183 } 5184 5185 vm_offset_t 5186 vm_map_min_KBI(const struct vm_map *map) 5187 { 5188 5189 return (vm_map_min(map)); 5190 } 5191 5192 pmap_t 5193 vm_map_pmap_KBI(vm_map_t map) 5194 { 5195 5196 return (map->pmap); 5197 } 5198 5199 bool 5200 vm_map_range_valid_KBI(vm_map_t map, vm_offset_t start, vm_offset_t end) 5201 { 5202 5203 return (vm_map_range_valid(map, start, end)); 5204 } 5205 5206 #ifdef INVARIANTS 5207 static void 5208 _vm_map_assert_consistent(vm_map_t map, int check) 5209 { 5210 vm_map_entry_t entry, prev; 5211 vm_map_entry_t cur, header, lbound, ubound; 5212 vm_size_t max_left, max_right; 5213 5214 #ifdef DIAGNOSTIC 5215 ++map->nupdates; 5216 #endif 5217 if (enable_vmmap_check != check) 5218 return; 5219 5220 header = prev = &map->header; 5221 VM_MAP_ENTRY_FOREACH(entry, map) { 5222 KASSERT(prev->end <= entry->start, 5223 ("map %p prev->end = %jx, start = %jx", map, 5224 (uintmax_t)prev->end, (uintmax_t)entry->start)); 5225 KASSERT(entry->start < entry->end, 5226 ("map %p start = %jx, end = %jx", map, 5227 (uintmax_t)entry->start, (uintmax_t)entry->end)); 5228 KASSERT(entry->left == header || 5229 entry->left->start < entry->start, 5230 ("map %p left->start = %jx, start = %jx", map, 5231 (uintmax_t)entry->left->start, (uintmax_t)entry->start)); 5232 KASSERT(entry->right == header || 5233 entry->start < entry->right->start, 5234 ("map %p start = %jx, right->start = %jx", map, 5235 (uintmax_t)entry->start, (uintmax_t)entry->right->start)); 5236 cur = map->root; 5237 lbound = ubound = header; 5238 for (;;) { 5239 if (entry->start < cur->start) { 5240 ubound = cur; 5241 cur = cur->left; 5242 KASSERT(cur != lbound, 5243 ("map %p cannot find %jx", 5244 map, (uintmax_t)entry->start)); 5245 } else if (cur->end <= entry->start) { 5246 lbound = cur; 5247 cur = cur->right; 5248 KASSERT(cur != ubound, 5249 ("map %p cannot find %jx", 5250 map, (uintmax_t)entry->start)); 5251 } else { 5252 KASSERT(cur == entry, 5253 ("map %p cannot find %jx", 5254 map, (uintmax_t)entry->start)); 5255 break; 5256 } 5257 } 5258 max_left = vm_map_entry_max_free_left(entry, lbound); 5259 max_right = vm_map_entry_max_free_right(entry, ubound); 5260 KASSERT(entry->max_free == vm_size_max(max_left, max_right), 5261 ("map %p max = %jx, max_left = %jx, max_right = %jx", map, 5262 (uintmax_t)entry->max_free, 5263 (uintmax_t)max_left, (uintmax_t)max_right)); 5264 prev = entry; 5265 } 5266 KASSERT(prev->end <= entry->start, 5267 ("map %p prev->end = %jx, start = %jx", map, 5268 (uintmax_t)prev->end, (uintmax_t)entry->start)); 5269 } 5270 #endif 5271 5272 #include "opt_ddb.h" 5273 #ifdef DDB 5274 #include <sys/kernel.h> 5275 5276 #include <ddb/ddb.h> 5277 5278 static void 5279 vm_map_print(vm_map_t map) 5280 { 5281 vm_map_entry_t entry, prev; 5282 5283 db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", 5284 (void *)map, 5285 (void *)map->pmap, map->nentries, map->timestamp); 5286 5287 db_indent += 2; 5288 prev = &map->header; 5289 VM_MAP_ENTRY_FOREACH(entry, map) { 5290 db_iprintf("map entry %p: start=%p, end=%p, eflags=%#x, \n", 5291 (void *)entry, (void *)entry->start, (void *)entry->end, 5292 entry->eflags); 5293 { 5294 static const char * const inheritance_name[4] = 5295 {"share", "copy", "none", "donate_copy"}; 5296 5297 db_iprintf(" prot=%x/%x/%s", 5298 entry->protection, 5299 entry->max_protection, 5300 inheritance_name[(int)(unsigned char) 5301 entry->inheritance]); 5302 if (entry->wired_count != 0) 5303 db_printf(", wired"); 5304 } 5305 if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 5306 db_printf(", share=%p, offset=0x%jx\n", 5307 (void *)entry->object.sub_map, 5308 (uintmax_t)entry->offset); 5309 if (prev == &map->header || 5310 prev->object.sub_map != 5311 entry->object.sub_map) { 5312 db_indent += 2; 5313 vm_map_print((vm_map_t)entry->object.sub_map); 5314 db_indent -= 2; 5315 } 5316 } else { 5317 if (entry->cred != NULL) 5318 db_printf(", ruid %d", entry->cred->cr_ruid); 5319 db_printf(", object=%p, offset=0x%jx", 5320 (void *)entry->object.vm_object, 5321 (uintmax_t)entry->offset); 5322 if (entry->object.vm_object && entry->object.vm_object->cred) 5323 db_printf(", obj ruid %d charge %jx", 5324 entry->object.vm_object->cred->cr_ruid, 5325 (uintmax_t)entry->object.vm_object->charge); 5326 if (entry->eflags & MAP_ENTRY_COW) 5327 db_printf(", copy (%s)", 5328 (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); 5329 db_printf("\n"); 5330 5331 if (prev == &map->header || 5332 prev->object.vm_object != 5333 entry->object.vm_object) { 5334 db_indent += 2; 5335 vm_object_print((db_expr_t)(intptr_t) 5336 entry->object.vm_object, 5337 0, 0, (char *)0); 5338 db_indent -= 2; 5339 } 5340 } 5341 prev = entry; 5342 } 5343 db_indent -= 2; 5344 } 5345 5346 DB_SHOW_COMMAND(map, map) 5347 { 5348 5349 if (!have_addr) { 5350 db_printf("usage: show map <addr>\n"); 5351 return; 5352 } 5353 vm_map_print((vm_map_t)addr); 5354 } 5355 5356 DB_SHOW_COMMAND(procvm, procvm) 5357 { 5358 struct proc *p; 5359 5360 if (have_addr) { 5361 p = db_lookup_proc(addr); 5362 } else { 5363 p = curproc; 5364 } 5365 5366 db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", 5367 (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, 5368 (void *)vmspace_pmap(p->p_vmspace)); 5369 5370 vm_map_print((vm_map_t)&p->p_vmspace->vm_map); 5371 } 5372 5373 #endif /* DDB */ 5374