1 /* 2 * (MPSAFE) 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)vm_map.c 8.3 (Berkeley) 1/12/94 39 * 40 * 41 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 42 * All rights reserved. 43 * 44 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 45 * 46 * Permission to use, copy, modify and distribute this software and 47 * its documentation is hereby granted, provided that both the copyright 48 * notice and this permission notice appear in all copies of the 49 * software, derivative works or modified versions, and any portions 50 * thereof, and that both notices appear in supporting documentation. 51 * 52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 53 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 54 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 55 * 56 * Carnegie Mellon requests users of this software to return to 57 * 58 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 59 * School of Computer Science 60 * Carnegie Mellon University 61 * Pittsburgh PA 15213-3890 62 * 63 * any improvements or extensions that they make and grant Carnegie the 64 * rights to redistribute these changes. 65 * 66 * $FreeBSD: src/sys/vm/vm_map.c,v 1.187.2.19 2003/05/27 00:47:02 alc Exp $ 67 */ 68 69 /* 70 * Virtual memory mapping module. 71 */ 72 73 #include <sys/param.h> 74 #include <sys/systm.h> 75 #include <sys/kernel.h> 76 #include <sys/proc.h> 77 #include <sys/serialize.h> 78 #include <sys/lock.h> 79 #include <sys/vmmeter.h> 80 #include <sys/mman.h> 81 #include <sys/vnode.h> 82 #include <sys/resourcevar.h> 83 #include <sys/shm.h> 84 #include <sys/tree.h> 85 #include <sys/malloc.h> 86 87 #include <vm/vm.h> 88 #include <vm/vm_param.h> 89 #include <vm/pmap.h> 90 #include <vm/vm_map.h> 91 #include <vm/vm_page.h> 92 #include <vm/vm_object.h> 93 #include <vm/vm_pager.h> 94 #include <vm/vm_kern.h> 95 #include <vm/vm_extern.h> 96 #include <vm/swap_pager.h> 97 #include <vm/vm_zone.h> 98 99 #include <sys/thread2.h> 100 #include <sys/sysref2.h> 101 #include <sys/random.h> 102 #include <sys/sysctl.h> 103 104 /* 105 * Virtual memory maps provide for the mapping, protection, and sharing 106 * of virtual memory objects. In addition, this module provides for an 107 * efficient virtual copy of 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 entries. 112 * A hint and a RB tree is used to speed-up lookups. 113 * 114 * Callers looking to modify maps specify start/end addresses which cause 115 * the related map entry to be clipped if necessary, and then later 116 * recombined if the pieces remained compatible. 117 * 118 * Virtual copy operations are performed by copying VM object references 119 * from one map to another, and then marking both regions as copy-on-write. 120 */ 121 static void vmspace_terminate(struct vmspace *vm); 122 static void vmspace_lock(struct vmspace *vm); 123 static void vmspace_unlock(struct vmspace *vm); 124 static void vmspace_dtor(void *obj, void *private); 125 126 MALLOC_DEFINE(M_VMSPACE, "vmspace", "vmspace objcache backingstore"); 127 128 struct sysref_class vmspace_sysref_class = { 129 .name = "vmspace", 130 .mtype = M_VMSPACE, 131 .proto = SYSREF_PROTO_VMSPACE, 132 .offset = offsetof(struct vmspace, vm_sysref), 133 .objsize = sizeof(struct vmspace), 134 .nom_cache = 32, 135 .flags = SRC_MANAGEDINIT, 136 .dtor = vmspace_dtor, 137 .ops = { 138 .terminate = (sysref_terminate_func_t)vmspace_terminate, 139 .lock = (sysref_lock_func_t)vmspace_lock, 140 .unlock = (sysref_lock_func_t)vmspace_unlock 141 } 142 }; 143 144 /* 145 * per-cpu page table cross mappings are initialized in early boot 146 * and might require a considerable number of vm_map_entry structures. 147 */ 148 #define VMEPERCPU (MAXCPU+1) 149 150 static struct vm_zone mapentzone_store, mapzone_store; 151 static vm_zone_t mapentzone, mapzone; 152 static struct vm_object mapentobj, mapobj; 153 154 static struct vm_map_entry map_entry_init[MAX_MAPENT]; 155 static struct vm_map_entry cpu_map_entry_init[MAXCPU][VMEPERCPU]; 156 static struct vm_map map_init[MAX_KMAP]; 157 158 static int randomize_mmap; 159 SYSCTL_INT(_vm, OID_AUTO, randomize_mmap, CTLFLAG_RW, &randomize_mmap, 0, 160 "Randomize mmap offsets"); 161 162 static void vm_map_entry_shadow(vm_map_entry_t entry, int addref); 163 static vm_map_entry_t vm_map_entry_create(vm_map_t map, int *); 164 static void vm_map_entry_dispose (vm_map_t map, vm_map_entry_t entry, int *); 165 static void _vm_map_clip_end (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 166 static void _vm_map_clip_start (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 167 static void vm_map_entry_delete (vm_map_t, vm_map_entry_t, int *); 168 static void vm_map_entry_unwire (vm_map_t, vm_map_entry_t); 169 static void vm_map_copy_entry (vm_map_t, vm_map_t, vm_map_entry_t, 170 vm_map_entry_t); 171 static void vm_map_unclip_range (vm_map_t map, vm_map_entry_t start_entry, vm_offset_t start, vm_offset_t end, int *count, int flags); 172 173 /* 174 * Initialize the vm_map module. Must be called before any other vm_map 175 * routines. 176 * 177 * Map and entry structures are allocated from the general purpose 178 * memory pool with some exceptions: 179 * 180 * - The kernel map is allocated statically. 181 * - Initial kernel map entries are allocated out of a static pool. 182 * 183 * These restrictions are necessary since malloc() uses the 184 * maps and requires map entries. 185 * 186 * Called from the low level boot code only. 187 */ 188 void 189 vm_map_startup(void) 190 { 191 mapzone = &mapzone_store; 192 zbootinit(mapzone, "MAP", sizeof (struct vm_map), 193 map_init, MAX_KMAP); 194 mapentzone = &mapentzone_store; 195 zbootinit(mapentzone, "MAP ENTRY", sizeof (struct vm_map_entry), 196 map_entry_init, MAX_MAPENT); 197 } 198 199 /* 200 * Called prior to any vmspace allocations. 201 * 202 * Called from the low level boot code only. 203 */ 204 void 205 vm_init2(void) 206 { 207 zinitna(mapentzone, &mapentobj, NULL, 0, 0, 208 ZONE_USE_RESERVE | ZONE_SPECIAL, 1); 209 zinitna(mapzone, &mapobj, NULL, 0, 0, 0, 1); 210 pmap_init2(); 211 vm_object_init2(); 212 } 213 214 215 /* 216 * Red black tree functions 217 * 218 * The caller must hold the related map lock. 219 */ 220 static int rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b); 221 RB_GENERATE(vm_map_rb_tree, vm_map_entry, rb_entry, rb_vm_map_compare); 222 223 /* a->start is address, and the only field has to be initialized */ 224 static int 225 rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b) 226 { 227 if (a->start < b->start) 228 return(-1); 229 else if (a->start > b->start) 230 return(1); 231 return(0); 232 } 233 234 /* 235 * Allocate a vmspace structure, including a vm_map and pmap. 236 * Initialize numerous fields. While the initial allocation is zerod, 237 * subsequence reuse from the objcache leaves elements of the structure 238 * intact (particularly the pmap), so portions must be zerod. 239 * 240 * The structure is not considered activated until we call sysref_activate(). 241 * 242 * No requirements. 243 */ 244 struct vmspace * 245 vmspace_alloc(vm_offset_t min, vm_offset_t max) 246 { 247 struct vmspace *vm; 248 249 vm = sysref_alloc(&vmspace_sysref_class); 250 bzero(&vm->vm_startcopy, 251 (char *)&vm->vm_endcopy - (char *)&vm->vm_startcopy); 252 vm_map_init(&vm->vm_map, min, max, NULL); /* initializes token */ 253 254 /* 255 * Use a hold to prevent any additional racing hold from terminating 256 * the vmspace before we manage to activate it. This also acquires 257 * the token for safety. 258 */ 259 KKASSERT(vm->vm_holdcount == 0); 260 KKASSERT(vm->vm_exitingcnt == 0); 261 vmspace_hold(vm); 262 pmap_pinit(vmspace_pmap(vm)); /* (some fields reused) */ 263 vm->vm_map.pmap = vmspace_pmap(vm); /* XXX */ 264 vm->vm_shm = NULL; 265 vm->vm_flags = 0; 266 cpu_vmspace_alloc(vm); 267 sysref_activate(&vm->vm_sysref); 268 vmspace_drop(vm); 269 270 return (vm); 271 } 272 273 /* 274 * Free a primary reference to a vmspace. This can trigger a 275 * stage-1 termination. 276 */ 277 void 278 vmspace_free(struct vmspace *vm) 279 { 280 /* 281 * We want all finalization to occur via vmspace_drop() so we 282 * need to hold the vm around the put. 283 */ 284 vmspace_hold(vm); 285 sysref_put(&vm->vm_sysref); 286 vmspace_drop(vm); 287 } 288 289 void 290 vmspace_ref(struct vmspace *vm) 291 { 292 sysref_get(&vm->vm_sysref); 293 } 294 295 void 296 vmspace_hold(struct vmspace *vm) 297 { 298 refcount_acquire(&vm->vm_holdcount); 299 lwkt_gettoken(&vm->vm_map.token); 300 } 301 302 void 303 vmspace_drop(struct vmspace *vm) 304 { 305 lwkt_reltoken(&vm->vm_map.token); 306 if (refcount_release(&vm->vm_holdcount)) { 307 if (vm->vm_exitingcnt == 0 && 308 sysref_isinactive(&vm->vm_sysref)) { 309 vmspace_terminate(vm); 310 } 311 } 312 } 313 314 /* 315 * dtor function - Some elements of the pmap are retained in the 316 * free-cached vmspaces to improve performance. We have to clean them up 317 * here before returning the vmspace to the memory pool. 318 * 319 * No requirements. 320 */ 321 static void 322 vmspace_dtor(void *obj, void *private) 323 { 324 struct vmspace *vm = obj; 325 326 pmap_puninit(vmspace_pmap(vm)); 327 } 328 329 /* 330 * Called in three cases: 331 * 332 * (1) When the last sysref is dropped and the vmspace becomes inactive. 333 * (holdcount will not be 0 because the vmspace is held through the op) 334 * 335 * (2) When exitingcount becomes 0 on the last reap 336 * (holdcount will not be 0 because the vmspace is held through the op) 337 * 338 * (3) When the holdcount becomes 0 in addition to the above two 339 * 340 * sysref will not scrap the object until we call sysref_put() once more 341 * after the last ref has been dropped. 342 * 343 * VMSPACE_EXIT1 flags the primary deactivation 344 * VMSPACE_EXIT2 flags the last reap 345 */ 346 static void 347 vmspace_terminate(struct vmspace *vm) 348 { 349 int count; 350 351 /* 352 * 353 */ 354 lwkt_gettoken(&vm->vm_map.token); 355 if ((vm->vm_flags & VMSPACE_EXIT1) == 0) { 356 vm->vm_flags |= VMSPACE_EXIT1; 357 shmexit(vm); 358 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_USER_ADDRESS, 359 VM_MAX_USER_ADDRESS); 360 vm_map_remove(&vm->vm_map, VM_MIN_USER_ADDRESS, 361 VM_MAX_USER_ADDRESS); 362 } 363 if ((vm->vm_flags & VMSPACE_EXIT2) == 0 && vm->vm_exitingcnt == 0) { 364 vm->vm_flags |= VMSPACE_EXIT2; 365 cpu_vmspace_free(vm); 366 shmexit(vm); 367 KKASSERT(vm->vm_upcalls == NULL); 368 369 /* 370 * Lock the map, to wait out all other references to it. 371 * Delete all of the mappings and pages they hold, then call 372 * the pmap module to reclaim anything left. 373 */ 374 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 375 vm_map_lock(&vm->vm_map); 376 vm_map_delete(&vm->vm_map, vm->vm_map.min_offset, 377 vm->vm_map.max_offset, &count); 378 vm_map_unlock(&vm->vm_map); 379 vm_map_entry_release(count); 380 381 lwkt_gettoken(&vmspace_pmap(vm)->pm_token); 382 pmap_release(vmspace_pmap(vm)); 383 lwkt_reltoken(&vmspace_pmap(vm)->pm_token); 384 } 385 386 lwkt_reltoken(&vm->vm_map.token); 387 if (vm->vm_exitingcnt == 0 && vm->vm_holdcount == 0) { 388 KKASSERT(vm->vm_flags & VMSPACE_EXIT1); 389 KKASSERT(vm->vm_flags & VMSPACE_EXIT2); 390 sysref_put(&vm->vm_sysref); 391 } 392 } 393 394 /* 395 * vmspaces are not currently locked. 396 */ 397 static void 398 vmspace_lock(struct vmspace *vm __unused) 399 { 400 } 401 402 static void 403 vmspace_unlock(struct vmspace *vm __unused) 404 { 405 } 406 407 /* 408 * This is called during exit indicating that the vmspace is no 409 * longer in used by an exiting process, but the process has not yet 410 * been reaped. 411 * 412 * No requirements. 413 */ 414 void 415 vmspace_exitbump(struct vmspace *vm) 416 { 417 vmspace_hold(vm); 418 ++vm->vm_exitingcnt; 419 vmspace_drop(vm); /* handles termination sequencing */ 420 } 421 422 /* 423 * Decrement the exitingcnt and issue the stage-2 termination if it becomes 424 * zero and the stage1 termination has already occured. 425 * 426 * No requirements. 427 */ 428 void 429 vmspace_exitfree(struct proc *p) 430 { 431 struct vmspace *vm; 432 433 vm = p->p_vmspace; 434 p->p_vmspace = NULL; 435 vmspace_hold(vm); 436 KKASSERT(vm->vm_exitingcnt > 0); 437 if (--vm->vm_exitingcnt == 0 && sysref_isinactive(&vm->vm_sysref)) 438 vmspace_terminate(vm); 439 vmspace_drop(vm); /* handles termination sequencing */ 440 } 441 442 /* 443 * Swap useage is determined by taking the proportional swap used by 444 * VM objects backing the VM map. To make up for fractional losses, 445 * if the VM object has any swap use at all the associated map entries 446 * count for at least 1 swap page. 447 * 448 * No requirements. 449 */ 450 int 451 vmspace_swap_count(struct vmspace *vm) 452 { 453 vm_map_t map = &vm->vm_map; 454 vm_map_entry_t cur; 455 vm_object_t object; 456 int count = 0; 457 int n; 458 459 vmspace_hold(vm); 460 for (cur = map->header.next; cur != &map->header; cur = cur->next) { 461 switch(cur->maptype) { 462 case VM_MAPTYPE_NORMAL: 463 case VM_MAPTYPE_VPAGETABLE: 464 if ((object = cur->object.vm_object) == NULL) 465 break; 466 if (object->swblock_count) { 467 n = (cur->end - cur->start) / PAGE_SIZE; 468 count += object->swblock_count * 469 SWAP_META_PAGES * n / object->size + 1; 470 } 471 break; 472 default: 473 break; 474 } 475 } 476 vmspace_drop(vm); 477 478 return(count); 479 } 480 481 /* 482 * Calculate the approximate number of anonymous pages in use by 483 * this vmspace. To make up for fractional losses, we count each 484 * VM object as having at least 1 anonymous page. 485 * 486 * No requirements. 487 */ 488 int 489 vmspace_anonymous_count(struct vmspace *vm) 490 { 491 vm_map_t map = &vm->vm_map; 492 vm_map_entry_t cur; 493 vm_object_t object; 494 int count = 0; 495 496 vmspace_hold(vm); 497 for (cur = map->header.next; cur != &map->header; cur = cur->next) { 498 switch(cur->maptype) { 499 case VM_MAPTYPE_NORMAL: 500 case VM_MAPTYPE_VPAGETABLE: 501 if ((object = cur->object.vm_object) == NULL) 502 break; 503 if (object->type != OBJT_DEFAULT && 504 object->type != OBJT_SWAP) { 505 break; 506 } 507 count += object->resident_page_count; 508 break; 509 default: 510 break; 511 } 512 } 513 vmspace_drop(vm); 514 515 return(count); 516 } 517 518 /* 519 * Creates and returns a new empty VM map with the given physical map 520 * structure, and having the given lower and upper address bounds. 521 * 522 * No requirements. 523 */ 524 vm_map_t 525 vm_map_create(vm_map_t result, pmap_t pmap, vm_offset_t min, vm_offset_t max) 526 { 527 if (result == NULL) 528 result = zalloc(mapzone); 529 vm_map_init(result, min, max, pmap); 530 return (result); 531 } 532 533 /* 534 * Initialize an existing vm_map structure such as that in the vmspace 535 * structure. The pmap is initialized elsewhere. 536 * 537 * No requirements. 538 */ 539 void 540 vm_map_init(struct vm_map *map, vm_offset_t min, vm_offset_t max, pmap_t pmap) 541 { 542 map->header.next = map->header.prev = &map->header; 543 RB_INIT(&map->rb_root); 544 map->nentries = 0; 545 map->size = 0; 546 map->system_map = 0; 547 map->min_offset = min; 548 map->max_offset = max; 549 map->pmap = pmap; 550 map->first_free = &map->header; 551 map->hint = &map->header; 552 map->timestamp = 0; 553 map->flags = 0; 554 lwkt_token_init(&map->token, "vm_map"); 555 lockinit(&map->lock, "thrd_sleep", (hz + 9) / 10, 0); 556 TUNABLE_INT("vm.cache_vmspaces", &vmspace_sysref_class.nom_cache); 557 } 558 559 /* 560 * Shadow the vm_map_entry's object. This typically needs to be done when 561 * a write fault is taken on an entry which had previously been cloned by 562 * fork(). The shared object (which might be NULL) must become private so 563 * we add a shadow layer above it. 564 * 565 * Object allocation for anonymous mappings is defered as long as possible. 566 * When creating a shadow, however, the underlying object must be instantiated 567 * so it can be shared. 568 * 569 * If the map segment is governed by a virtual page table then it is 570 * possible to address offsets beyond the mapped area. Just allocate 571 * a maximally sized object for this case. 572 * 573 * The vm_map must be exclusively locked. 574 * No other requirements. 575 */ 576 static 577 void 578 vm_map_entry_shadow(vm_map_entry_t entry, int addref) 579 { 580 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 581 vm_object_shadow(&entry->object.vm_object, &entry->offset, 582 0x7FFFFFFF, addref); /* XXX */ 583 } else { 584 vm_object_shadow(&entry->object.vm_object, &entry->offset, 585 atop(entry->end - entry->start), addref); 586 } 587 entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 588 } 589 590 /* 591 * Allocate an object for a vm_map_entry. 592 * 593 * Object allocation for anonymous mappings is defered as long as possible. 594 * This function is called when we can defer no longer, generally when a map 595 * entry might be split or forked or takes a page fault. 596 * 597 * If the map segment is governed by a virtual page table then it is 598 * possible to address offsets beyond the mapped area. Just allocate 599 * a maximally sized object for this case. 600 * 601 * The vm_map must be exclusively locked. 602 * No other requirements. 603 */ 604 void 605 vm_map_entry_allocate_object(vm_map_entry_t entry) 606 { 607 vm_object_t obj; 608 609 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 610 obj = vm_object_allocate(OBJT_DEFAULT, 0x7FFFFFFF); /* XXX */ 611 } else { 612 obj = vm_object_allocate(OBJT_DEFAULT, 613 atop(entry->end - entry->start)); 614 } 615 entry->object.vm_object = obj; 616 entry->offset = 0; 617 } 618 619 /* 620 * Set an initial negative count so the first attempt to reserve 621 * space preloads a bunch of vm_map_entry's for this cpu. Also 622 * pre-allocate 2 vm_map_entries which will be needed by zalloc() to 623 * map a new page for vm_map_entry structures. SMP systems are 624 * particularly sensitive. 625 * 626 * This routine is called in early boot so we cannot just call 627 * vm_map_entry_reserve(). 628 * 629 * Called from the low level boot code only (for each cpu) 630 */ 631 void 632 vm_map_entry_reserve_cpu_init(globaldata_t gd) 633 { 634 vm_map_entry_t entry; 635 int i; 636 637 gd->gd_vme_avail -= MAP_RESERVE_COUNT * 2; 638 entry = &cpu_map_entry_init[gd->gd_cpuid][0]; 639 for (i = 0; i < VMEPERCPU; ++i, ++entry) { 640 entry->next = gd->gd_vme_base; 641 gd->gd_vme_base = entry; 642 } 643 } 644 645 /* 646 * Reserves vm_map_entry structures so code later on can manipulate 647 * map_entry structures within a locked map without blocking trying 648 * to allocate a new vm_map_entry. 649 * 650 * No requirements. 651 */ 652 int 653 vm_map_entry_reserve(int count) 654 { 655 struct globaldata *gd = mycpu; 656 vm_map_entry_t entry; 657 658 /* 659 * Make sure we have enough structures in gd_vme_base to handle 660 * the reservation request. 661 * 662 * The critical section protects access to the per-cpu gd. 663 */ 664 crit_enter(); 665 while (gd->gd_vme_avail < count) { 666 entry = zalloc(mapentzone); 667 entry->next = gd->gd_vme_base; 668 gd->gd_vme_base = entry; 669 ++gd->gd_vme_avail; 670 } 671 gd->gd_vme_avail -= count; 672 crit_exit(); 673 674 return(count); 675 } 676 677 /* 678 * Releases previously reserved vm_map_entry structures that were not 679 * used. If we have too much junk in our per-cpu cache clean some of 680 * it out. 681 * 682 * No requirements. 683 */ 684 void 685 vm_map_entry_release(int count) 686 { 687 struct globaldata *gd = mycpu; 688 vm_map_entry_t entry; 689 690 crit_enter(); 691 gd->gd_vme_avail += count; 692 while (gd->gd_vme_avail > MAP_RESERVE_SLOP) { 693 entry = gd->gd_vme_base; 694 KKASSERT(entry != NULL); 695 gd->gd_vme_base = entry->next; 696 --gd->gd_vme_avail; 697 crit_exit(); 698 zfree(mapentzone, entry); 699 crit_enter(); 700 } 701 crit_exit(); 702 } 703 704 /* 705 * Reserve map entry structures for use in kernel_map itself. These 706 * entries have *ALREADY* been reserved on a per-cpu basis when the map 707 * was inited. This function is used by zalloc() to avoid a recursion 708 * when zalloc() itself needs to allocate additional kernel memory. 709 * 710 * This function works like the normal reserve but does not load the 711 * vm_map_entry cache (because that would result in an infinite 712 * recursion). Note that gd_vme_avail may go negative. This is expected. 713 * 714 * Any caller of this function must be sure to renormalize after 715 * potentially eating entries to ensure that the reserve supply 716 * remains intact. 717 * 718 * No requirements. 719 */ 720 int 721 vm_map_entry_kreserve(int count) 722 { 723 struct globaldata *gd = mycpu; 724 725 crit_enter(); 726 gd->gd_vme_avail -= count; 727 crit_exit(); 728 KASSERT(gd->gd_vme_base != NULL, 729 ("no reserved entries left, gd_vme_avail = %d", 730 gd->gd_vme_avail)); 731 return(count); 732 } 733 734 /* 735 * Release previously reserved map entries for kernel_map. We do not 736 * attempt to clean up like the normal release function as this would 737 * cause an unnecessary (but probably not fatal) deep procedure call. 738 * 739 * No requirements. 740 */ 741 void 742 vm_map_entry_krelease(int count) 743 { 744 struct globaldata *gd = mycpu; 745 746 crit_enter(); 747 gd->gd_vme_avail += count; 748 crit_exit(); 749 } 750 751 /* 752 * Allocates a VM map entry for insertion. No entry fields are filled in. 753 * 754 * The entries should have previously been reserved. The reservation count 755 * is tracked in (*countp). 756 * 757 * No requirements. 758 */ 759 static vm_map_entry_t 760 vm_map_entry_create(vm_map_t map, int *countp) 761 { 762 struct globaldata *gd = mycpu; 763 vm_map_entry_t entry; 764 765 KKASSERT(*countp > 0); 766 --*countp; 767 crit_enter(); 768 entry = gd->gd_vme_base; 769 KASSERT(entry != NULL, ("gd_vme_base NULL! count %d", *countp)); 770 gd->gd_vme_base = entry->next; 771 crit_exit(); 772 773 return(entry); 774 } 775 776 /* 777 * Dispose of a vm_map_entry that is no longer being referenced. 778 * 779 * No requirements. 780 */ 781 static void 782 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry, int *countp) 783 { 784 struct globaldata *gd = mycpu; 785 786 KKASSERT(map->hint != entry); 787 KKASSERT(map->first_free != entry); 788 789 ++*countp; 790 crit_enter(); 791 entry->next = gd->gd_vme_base; 792 gd->gd_vme_base = entry; 793 crit_exit(); 794 } 795 796 797 /* 798 * Insert/remove entries from maps. 799 * 800 * The related map must be exclusively locked. 801 * The caller must hold map->token 802 * No other requirements. 803 */ 804 static __inline void 805 vm_map_entry_link(vm_map_t map, 806 vm_map_entry_t after_where, 807 vm_map_entry_t entry) 808 { 809 ASSERT_VM_MAP_LOCKED(map); 810 811 map->nentries++; 812 entry->prev = after_where; 813 entry->next = after_where->next; 814 entry->next->prev = entry; 815 after_where->next = entry; 816 if (vm_map_rb_tree_RB_INSERT(&map->rb_root, entry)) 817 panic("vm_map_entry_link: dup addr map %p ent %p", map, entry); 818 } 819 820 static __inline void 821 vm_map_entry_unlink(vm_map_t map, 822 vm_map_entry_t entry) 823 { 824 vm_map_entry_t prev; 825 vm_map_entry_t next; 826 827 ASSERT_VM_MAP_LOCKED(map); 828 829 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 830 panic("vm_map_entry_unlink: attempt to mess with " 831 "locked entry! %p", entry); 832 } 833 prev = entry->prev; 834 next = entry->next; 835 next->prev = prev; 836 prev->next = next; 837 vm_map_rb_tree_RB_REMOVE(&map->rb_root, entry); 838 map->nentries--; 839 } 840 841 /* 842 * Finds the map entry containing (or immediately preceding) the specified 843 * address in the given map. The entry is returned in (*entry). 844 * 845 * The boolean result indicates whether the address is actually contained 846 * in the map. 847 * 848 * The related map must be locked. 849 * No other requirements. 850 */ 851 boolean_t 852 vm_map_lookup_entry(vm_map_t map, vm_offset_t address, vm_map_entry_t *entry) 853 { 854 vm_map_entry_t tmp; 855 vm_map_entry_t last; 856 857 ASSERT_VM_MAP_LOCKED(map); 858 #if 0 859 /* 860 * XXX TEMPORARILY DISABLED. For some reason our attempt to revive 861 * the hint code with the red-black lookup meets with system crashes 862 * and lockups. We do not yet know why. 863 * 864 * It is possible that the problem is related to the setting 865 * of the hint during map_entry deletion, in the code specified 866 * at the GGG comment later on in this file. 867 * 868 * YYY More likely it's because this function can be called with 869 * a shared lock on the map, resulting in map->hint updates possibly 870 * racing. Fixed now but untested. 871 */ 872 /* 873 * Quickly check the cached hint, there's a good chance of a match. 874 */ 875 tmp = map->hint; 876 cpu_ccfence(); 877 if (tmp != &map->header) { 878 if (address >= tmp->start && address < tmp->end) { 879 *entry = tmp; 880 return(TRUE); 881 } 882 } 883 #endif 884 885 /* 886 * Locate the record from the top of the tree. 'last' tracks the 887 * closest prior record and is returned if no match is found, which 888 * in binary tree terms means tracking the most recent right-branch 889 * taken. If there is no prior record, &map->header is returned. 890 */ 891 last = &map->header; 892 tmp = RB_ROOT(&map->rb_root); 893 894 while (tmp) { 895 if (address >= tmp->start) { 896 if (address < tmp->end) { 897 *entry = tmp; 898 map->hint = tmp; 899 return(TRUE); 900 } 901 last = tmp; 902 tmp = RB_RIGHT(tmp, rb_entry); 903 } else { 904 tmp = RB_LEFT(tmp, rb_entry); 905 } 906 } 907 *entry = last; 908 return (FALSE); 909 } 910 911 /* 912 * Inserts the given whole VM object into the target map at the specified 913 * address range. The object's size should match that of the address range. 914 * 915 * The map must be exclusively locked. 916 * The object must be held. 917 * The caller must have reserved sufficient vm_map_entry structures. 918 * 919 * If object is non-NULL, ref count must be bumped by caller prior to 920 * making call to account for the new entry. 921 */ 922 int 923 vm_map_insert(vm_map_t map, int *countp, 924 vm_object_t object, vm_ooffset_t offset, 925 vm_offset_t start, vm_offset_t end, 926 vm_maptype_t maptype, 927 vm_prot_t prot, vm_prot_t max, 928 int cow) 929 { 930 vm_map_entry_t new_entry; 931 vm_map_entry_t prev_entry; 932 vm_map_entry_t temp_entry; 933 vm_eflags_t protoeflags; 934 int must_drop = 0; 935 936 ASSERT_VM_MAP_LOCKED(map); 937 if (object) 938 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 939 940 /* 941 * Check that the start and end points are not bogus. 942 */ 943 if ((start < map->min_offset) || (end > map->max_offset) || 944 (start >= end)) 945 return (KERN_INVALID_ADDRESS); 946 947 /* 948 * Find the entry prior to the proposed starting address; if it's part 949 * of an existing entry, this range is bogus. 950 */ 951 if (vm_map_lookup_entry(map, start, &temp_entry)) 952 return (KERN_NO_SPACE); 953 954 prev_entry = temp_entry; 955 956 /* 957 * Assert that the next entry doesn't overlap the end point. 958 */ 959 960 if ((prev_entry->next != &map->header) && 961 (prev_entry->next->start < end)) 962 return (KERN_NO_SPACE); 963 964 protoeflags = 0; 965 966 if (cow & MAP_COPY_ON_WRITE) 967 protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY; 968 969 if (cow & MAP_NOFAULT) { 970 protoeflags |= MAP_ENTRY_NOFAULT; 971 972 KASSERT(object == NULL, 973 ("vm_map_insert: paradoxical MAP_NOFAULT request")); 974 } 975 if (cow & MAP_DISABLE_SYNCER) 976 protoeflags |= MAP_ENTRY_NOSYNC; 977 if (cow & MAP_DISABLE_COREDUMP) 978 protoeflags |= MAP_ENTRY_NOCOREDUMP; 979 if (cow & MAP_IS_STACK) 980 protoeflags |= MAP_ENTRY_STACK; 981 if (cow & MAP_IS_KSTACK) 982 protoeflags |= MAP_ENTRY_KSTACK; 983 984 lwkt_gettoken(&map->token); 985 986 if (object) { 987 /* 988 * When object is non-NULL, it could be shared with another 989 * process. We have to set or clear OBJ_ONEMAPPING 990 * appropriately. 991 */ 992 if ((object->ref_count > 1) || (object->shadow_count != 0)) { 993 vm_object_clear_flag(object, OBJ_ONEMAPPING); 994 } 995 } 996 else if ((prev_entry != &map->header) && 997 (prev_entry->eflags == protoeflags) && 998 (prev_entry->end == start) && 999 (prev_entry->wired_count == 0) && 1000 prev_entry->maptype == maptype && 1001 ((prev_entry->object.vm_object == NULL) || 1002 vm_object_coalesce(prev_entry->object.vm_object, 1003 OFF_TO_IDX(prev_entry->offset), 1004 (vm_size_t)(prev_entry->end - prev_entry->start), 1005 (vm_size_t)(end - prev_entry->end)))) { 1006 /* 1007 * We were able to extend the object. Determine if we 1008 * can extend the previous map entry to include the 1009 * new range as well. 1010 */ 1011 if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) && 1012 (prev_entry->protection == prot) && 1013 (prev_entry->max_protection == max)) { 1014 map->size += (end - prev_entry->end); 1015 prev_entry->end = end; 1016 vm_map_simplify_entry(map, prev_entry, countp); 1017 lwkt_reltoken(&map->token); 1018 return (KERN_SUCCESS); 1019 } 1020 1021 /* 1022 * If we can extend the object but cannot extend the 1023 * map entry, we have to create a new map entry. We 1024 * must bump the ref count on the extended object to 1025 * account for it. object may be NULL. 1026 */ 1027 object = prev_entry->object.vm_object; 1028 offset = prev_entry->offset + 1029 (prev_entry->end - prev_entry->start); 1030 if (object) { 1031 vm_object_hold(object); 1032 vm_object_chain_wait(object); 1033 vm_object_reference_locked(object); 1034 must_drop = 1; 1035 } 1036 } 1037 1038 /* 1039 * NOTE: if conditionals fail, object can be NULL here. This occurs 1040 * in things like the buffer map where we manage kva but do not manage 1041 * backing objects. 1042 */ 1043 1044 /* 1045 * Create a new entry 1046 */ 1047 1048 new_entry = vm_map_entry_create(map, countp); 1049 new_entry->start = start; 1050 new_entry->end = end; 1051 1052 new_entry->maptype = maptype; 1053 new_entry->eflags = protoeflags; 1054 new_entry->object.vm_object = object; 1055 new_entry->offset = offset; 1056 new_entry->aux.master_pde = 0; 1057 1058 new_entry->inheritance = VM_INHERIT_DEFAULT; 1059 new_entry->protection = prot; 1060 new_entry->max_protection = max; 1061 new_entry->wired_count = 0; 1062 1063 /* 1064 * Insert the new entry into the list 1065 */ 1066 1067 vm_map_entry_link(map, prev_entry, new_entry); 1068 map->size += new_entry->end - new_entry->start; 1069 1070 /* 1071 * Update the free space hint. Entries cannot overlap. 1072 * An exact comparison is needed to avoid matching 1073 * against the map->header. 1074 */ 1075 if ((map->first_free == prev_entry) && 1076 (prev_entry->end == new_entry->start)) { 1077 map->first_free = new_entry; 1078 } 1079 1080 #if 0 1081 /* 1082 * Temporarily removed to avoid MAP_STACK panic, due to 1083 * MAP_STACK being a huge hack. Will be added back in 1084 * when MAP_STACK (and the user stack mapping) is fixed. 1085 */ 1086 /* 1087 * It may be possible to simplify the entry 1088 */ 1089 vm_map_simplify_entry(map, new_entry, countp); 1090 #endif 1091 1092 /* 1093 * Try to pre-populate the page table. Mappings governed by virtual 1094 * page tables cannot be prepopulated without a lot of work, so 1095 * don't try. 1096 */ 1097 if ((cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) && 1098 maptype != VM_MAPTYPE_VPAGETABLE) { 1099 pmap_object_init_pt(map->pmap, start, prot, 1100 object, OFF_TO_IDX(offset), end - start, 1101 cow & MAP_PREFAULT_PARTIAL); 1102 } 1103 if (must_drop) 1104 vm_object_drop(object); 1105 1106 lwkt_reltoken(&map->token); 1107 return (KERN_SUCCESS); 1108 } 1109 1110 /* 1111 * Find sufficient space for `length' bytes in the given map, starting at 1112 * `start'. Returns 0 on success, 1 on no space. 1113 * 1114 * This function will returned an arbitrarily aligned pointer. If no 1115 * particular alignment is required you should pass align as 1. Note that 1116 * the map may return PAGE_SIZE aligned pointers if all the lengths used in 1117 * the map are a multiple of PAGE_SIZE, even if you pass a smaller align 1118 * argument. 1119 * 1120 * 'align' should be a power of 2 but is not required to be. 1121 * 1122 * The map must be exclusively locked. 1123 * No other requirements. 1124 */ 1125 int 1126 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, 1127 vm_size_t align, int flags, vm_offset_t *addr) 1128 { 1129 vm_map_entry_t entry, next; 1130 vm_offset_t end; 1131 vm_offset_t align_mask; 1132 1133 if (start < map->min_offset) 1134 start = map->min_offset; 1135 if (start > map->max_offset) 1136 return (1); 1137 1138 /* 1139 * If the alignment is not a power of 2 we will have to use 1140 * a mod/division, set align_mask to a special value. 1141 */ 1142 if ((align | (align - 1)) + 1 != (align << 1)) 1143 align_mask = (vm_offset_t)-1; 1144 else 1145 align_mask = align - 1; 1146 1147 /* 1148 * Look for the first possible address; if there's already something 1149 * at this address, we have to start after it. 1150 */ 1151 if (start == map->min_offset) { 1152 if ((entry = map->first_free) != &map->header) 1153 start = entry->end; 1154 } else { 1155 vm_map_entry_t tmp; 1156 1157 if (vm_map_lookup_entry(map, start, &tmp)) 1158 start = tmp->end; 1159 entry = tmp; 1160 } 1161 1162 /* 1163 * Look through the rest of the map, trying to fit a new region in the 1164 * gap between existing regions, or after the very last region. 1165 */ 1166 for (;; start = (entry = next)->end) { 1167 /* 1168 * Adjust the proposed start by the requested alignment, 1169 * be sure that we didn't wrap the address. 1170 */ 1171 if (align_mask == (vm_offset_t)-1) 1172 end = ((start + align - 1) / align) * align; 1173 else 1174 end = (start + align_mask) & ~align_mask; 1175 if (end < start) 1176 return (1); 1177 start = end; 1178 /* 1179 * Find the end of the proposed new region. Be sure we didn't 1180 * go beyond the end of the map, or wrap around the address. 1181 * Then check to see if this is the last entry or if the 1182 * proposed end fits in the gap between this and the next 1183 * entry. 1184 */ 1185 end = start + length; 1186 if (end > map->max_offset || end < start) 1187 return (1); 1188 next = entry->next; 1189 1190 /* 1191 * If the next entry's start address is beyond the desired 1192 * end address we may have found a good entry. 1193 * 1194 * If the next entry is a stack mapping we do not map into 1195 * the stack's reserved space. 1196 * 1197 * XXX continue to allow mapping into the stack's reserved 1198 * space if doing a MAP_STACK mapping inside a MAP_STACK 1199 * mapping, for backwards compatibility. But the caller 1200 * really should use MAP_STACK | MAP_TRYFIXED if they 1201 * want to do that. 1202 */ 1203 if (next == &map->header) 1204 break; 1205 if (next->start >= end) { 1206 if ((next->eflags & MAP_ENTRY_STACK) == 0) 1207 break; 1208 if (flags & MAP_STACK) 1209 break; 1210 if (next->start - next->aux.avail_ssize >= end) 1211 break; 1212 } 1213 } 1214 map->hint = entry; 1215 1216 /* 1217 * Grow the kernel_map if necessary. pmap_growkernel() will panic 1218 * if it fails. The kernel_map is locked and nothing can steal 1219 * our address space if pmap_growkernel() blocks. 1220 * 1221 * NOTE: This may be unconditionally called for kldload areas on 1222 * x86_64 because these do not bump kernel_vm_end (which would 1223 * fill 128G worth of page tables!). Therefore we must not 1224 * retry. 1225 */ 1226 if (map == &kernel_map) { 1227 vm_offset_t kstop; 1228 1229 kstop = round_page(start + length); 1230 if (kstop > kernel_vm_end) 1231 pmap_growkernel(start, kstop); 1232 } 1233 *addr = start; 1234 return (0); 1235 } 1236 1237 /* 1238 * vm_map_find finds an unallocated region in the target address map with 1239 * the given length and allocates it. The search is defined to be first-fit 1240 * from the specified address; the region found is returned in the same 1241 * parameter. 1242 * 1243 * If object is non-NULL, ref count must be bumped by caller 1244 * prior to making call to account for the new entry. 1245 * 1246 * No requirements. This function will lock the map temporarily. 1247 */ 1248 int 1249 vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1250 vm_offset_t *addr, vm_size_t length, vm_size_t align, 1251 boolean_t fitit, 1252 vm_maptype_t maptype, 1253 vm_prot_t prot, vm_prot_t max, 1254 int cow) 1255 { 1256 vm_offset_t start; 1257 int result; 1258 int count; 1259 1260 start = *addr; 1261 1262 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1263 vm_map_lock(map); 1264 if (object) 1265 vm_object_hold(object); 1266 if (fitit) { 1267 if (vm_map_findspace(map, start, length, align, 0, addr)) { 1268 if (object) 1269 vm_object_drop(object); 1270 vm_map_unlock(map); 1271 vm_map_entry_release(count); 1272 return (KERN_NO_SPACE); 1273 } 1274 start = *addr; 1275 } 1276 result = vm_map_insert(map, &count, object, offset, 1277 start, start + length, 1278 maptype, 1279 prot, max, 1280 cow); 1281 if (object) 1282 vm_object_drop(object); 1283 vm_map_unlock(map); 1284 vm_map_entry_release(count); 1285 1286 return (result); 1287 } 1288 1289 /* 1290 * Simplify the given map entry by merging with either neighbor. This 1291 * routine also has the ability to merge with both neighbors. 1292 * 1293 * This routine guarentees that the passed entry remains valid (though 1294 * possibly extended). When merging, this routine may delete one or 1295 * both neighbors. No action is taken on entries which have their 1296 * in-transition flag set. 1297 * 1298 * The map must be exclusively locked. 1299 */ 1300 void 1301 vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry, int *countp) 1302 { 1303 vm_map_entry_t next, prev; 1304 vm_size_t prevsize, esize; 1305 1306 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1307 ++mycpu->gd_cnt.v_intrans_coll; 1308 return; 1309 } 1310 1311 if (entry->maptype == VM_MAPTYPE_SUBMAP) 1312 return; 1313 1314 prev = entry->prev; 1315 if (prev != &map->header) { 1316 prevsize = prev->end - prev->start; 1317 if ( (prev->end == entry->start) && 1318 (prev->maptype == entry->maptype) && 1319 (prev->object.vm_object == entry->object.vm_object) && 1320 (!prev->object.vm_object || 1321 (prev->offset + prevsize == entry->offset)) && 1322 (prev->eflags == entry->eflags) && 1323 (prev->protection == entry->protection) && 1324 (prev->max_protection == entry->max_protection) && 1325 (prev->inheritance == entry->inheritance) && 1326 (prev->wired_count == entry->wired_count)) { 1327 if (map->first_free == prev) 1328 map->first_free = entry; 1329 if (map->hint == prev) 1330 map->hint = entry; 1331 vm_map_entry_unlink(map, prev); 1332 entry->start = prev->start; 1333 entry->offset = prev->offset; 1334 if (prev->object.vm_object) 1335 vm_object_deallocate(prev->object.vm_object); 1336 vm_map_entry_dispose(map, prev, countp); 1337 } 1338 } 1339 1340 next = entry->next; 1341 if (next != &map->header) { 1342 esize = entry->end - entry->start; 1343 if ((entry->end == next->start) && 1344 (next->maptype == entry->maptype) && 1345 (next->object.vm_object == entry->object.vm_object) && 1346 (!entry->object.vm_object || 1347 (entry->offset + esize == next->offset)) && 1348 (next->eflags == entry->eflags) && 1349 (next->protection == entry->protection) && 1350 (next->max_protection == entry->max_protection) && 1351 (next->inheritance == entry->inheritance) && 1352 (next->wired_count == entry->wired_count)) { 1353 if (map->first_free == next) 1354 map->first_free = entry; 1355 if (map->hint == next) 1356 map->hint = entry; 1357 vm_map_entry_unlink(map, next); 1358 entry->end = next->end; 1359 if (next->object.vm_object) 1360 vm_object_deallocate(next->object.vm_object); 1361 vm_map_entry_dispose(map, next, countp); 1362 } 1363 } 1364 } 1365 1366 /* 1367 * Asserts that the given entry begins at or after the specified address. 1368 * If necessary, it splits the entry into two. 1369 */ 1370 #define vm_map_clip_start(map, entry, startaddr, countp) \ 1371 { \ 1372 if (startaddr > entry->start) \ 1373 _vm_map_clip_start(map, entry, startaddr, countp); \ 1374 } 1375 1376 /* 1377 * This routine is called only when it is known that the entry must be split. 1378 * 1379 * The map must be exclusively locked. 1380 */ 1381 static void 1382 _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start, 1383 int *countp) 1384 { 1385 vm_map_entry_t new_entry; 1386 1387 /* 1388 * Split off the front portion -- note that we must insert the new 1389 * entry BEFORE this one, so that this entry has the specified 1390 * starting address. 1391 */ 1392 1393 vm_map_simplify_entry(map, entry, countp); 1394 1395 /* 1396 * If there is no object backing this entry, we might as well create 1397 * one now. If we defer it, an object can get created after the map 1398 * is clipped, and individual objects will be created for the split-up 1399 * map. This is a bit of a hack, but is also about the best place to 1400 * put this improvement. 1401 */ 1402 if (entry->object.vm_object == NULL && !map->system_map) { 1403 vm_map_entry_allocate_object(entry); 1404 } 1405 1406 new_entry = vm_map_entry_create(map, countp); 1407 *new_entry = *entry; 1408 1409 new_entry->end = start; 1410 entry->offset += (start - entry->start); 1411 entry->start = start; 1412 1413 vm_map_entry_link(map, entry->prev, new_entry); 1414 1415 switch(entry->maptype) { 1416 case VM_MAPTYPE_NORMAL: 1417 case VM_MAPTYPE_VPAGETABLE: 1418 if (new_entry->object.vm_object) { 1419 vm_object_hold(new_entry->object.vm_object); 1420 vm_object_chain_wait(new_entry->object.vm_object); 1421 vm_object_reference_locked(new_entry->object.vm_object); 1422 vm_object_drop(new_entry->object.vm_object); 1423 } 1424 break; 1425 default: 1426 break; 1427 } 1428 } 1429 1430 /* 1431 * Asserts that the given entry ends at or before the specified address. 1432 * If necessary, it splits the entry into two. 1433 * 1434 * The map must be exclusively locked. 1435 */ 1436 #define vm_map_clip_end(map, entry, endaddr, countp) \ 1437 { \ 1438 if (endaddr < entry->end) \ 1439 _vm_map_clip_end(map, entry, endaddr, countp); \ 1440 } 1441 1442 /* 1443 * This routine is called only when it is known that the entry must be split. 1444 * 1445 * The map must be exclusively locked. 1446 */ 1447 static void 1448 _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end, 1449 int *countp) 1450 { 1451 vm_map_entry_t new_entry; 1452 1453 /* 1454 * If there is no object backing this entry, we might as well create 1455 * one now. If we defer it, an object can get created after the map 1456 * is clipped, and individual objects will be created for the split-up 1457 * map. This is a bit of a hack, but is also about the best place to 1458 * put this improvement. 1459 */ 1460 1461 if (entry->object.vm_object == NULL && !map->system_map) { 1462 vm_map_entry_allocate_object(entry); 1463 } 1464 1465 /* 1466 * Create a new entry and insert it AFTER the specified entry 1467 */ 1468 1469 new_entry = vm_map_entry_create(map, countp); 1470 *new_entry = *entry; 1471 1472 new_entry->start = entry->end = end; 1473 new_entry->offset += (end - entry->start); 1474 1475 vm_map_entry_link(map, entry, new_entry); 1476 1477 switch(entry->maptype) { 1478 case VM_MAPTYPE_NORMAL: 1479 case VM_MAPTYPE_VPAGETABLE: 1480 if (new_entry->object.vm_object) { 1481 vm_object_hold(new_entry->object.vm_object); 1482 vm_object_chain_wait(new_entry->object.vm_object); 1483 vm_object_reference_locked(new_entry->object.vm_object); 1484 vm_object_drop(new_entry->object.vm_object); 1485 } 1486 break; 1487 default: 1488 break; 1489 } 1490 } 1491 1492 /* 1493 * Asserts that the starting and ending region addresses fall within the 1494 * valid range for the map. 1495 */ 1496 #define VM_MAP_RANGE_CHECK(map, start, end) \ 1497 { \ 1498 if (start < vm_map_min(map)) \ 1499 start = vm_map_min(map); \ 1500 if (end > vm_map_max(map)) \ 1501 end = vm_map_max(map); \ 1502 if (start > end) \ 1503 start = end; \ 1504 } 1505 1506 /* 1507 * Used to block when an in-transition collison occurs. The map 1508 * is unlocked for the sleep and relocked before the return. 1509 */ 1510 void 1511 vm_map_transition_wait(vm_map_t map) 1512 { 1513 tsleep_interlock(map, 0); 1514 vm_map_unlock(map); 1515 tsleep(map, PINTERLOCKED, "vment", 0); 1516 vm_map_lock(map); 1517 } 1518 1519 /* 1520 * When we do blocking operations with the map lock held it is 1521 * possible that a clip might have occured on our in-transit entry, 1522 * requiring an adjustment to the entry in our loop. These macros 1523 * help the pageable and clip_range code deal with the case. The 1524 * conditional costs virtually nothing if no clipping has occured. 1525 */ 1526 1527 #define CLIP_CHECK_BACK(entry, save_start) \ 1528 do { \ 1529 while (entry->start != save_start) { \ 1530 entry = entry->prev; \ 1531 KASSERT(entry != &map->header, ("bad entry clip")); \ 1532 } \ 1533 } while(0) 1534 1535 #define CLIP_CHECK_FWD(entry, save_end) \ 1536 do { \ 1537 while (entry->end != save_end) { \ 1538 entry = entry->next; \ 1539 KASSERT(entry != &map->header, ("bad entry clip")); \ 1540 } \ 1541 } while(0) 1542 1543 1544 /* 1545 * Clip the specified range and return the base entry. The 1546 * range may cover several entries starting at the returned base 1547 * and the first and last entry in the covering sequence will be 1548 * properly clipped to the requested start and end address. 1549 * 1550 * If no holes are allowed you should pass the MAP_CLIP_NO_HOLES 1551 * flag. 1552 * 1553 * The MAP_ENTRY_IN_TRANSITION flag will be set for the entries 1554 * covered by the requested range. 1555 * 1556 * The map must be exclusively locked on entry and will remain locked 1557 * on return. If no range exists or the range contains holes and you 1558 * specified that no holes were allowed, NULL will be returned. This 1559 * routine may temporarily unlock the map in order avoid a deadlock when 1560 * sleeping. 1561 */ 1562 static 1563 vm_map_entry_t 1564 vm_map_clip_range(vm_map_t map, vm_offset_t start, vm_offset_t end, 1565 int *countp, int flags) 1566 { 1567 vm_map_entry_t start_entry; 1568 vm_map_entry_t entry; 1569 1570 /* 1571 * Locate the entry and effect initial clipping. The in-transition 1572 * case does not occur very often so do not try to optimize it. 1573 */ 1574 again: 1575 if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) 1576 return (NULL); 1577 entry = start_entry; 1578 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1579 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1580 ++mycpu->gd_cnt.v_intrans_coll; 1581 ++mycpu->gd_cnt.v_intrans_wait; 1582 vm_map_transition_wait(map); 1583 /* 1584 * entry and/or start_entry may have been clipped while 1585 * we slept, or may have gone away entirely. We have 1586 * to restart from the lookup. 1587 */ 1588 goto again; 1589 } 1590 1591 /* 1592 * Since we hold an exclusive map lock we do not have to restart 1593 * after clipping, even though clipping may block in zalloc. 1594 */ 1595 vm_map_clip_start(map, entry, start, countp); 1596 vm_map_clip_end(map, entry, end, countp); 1597 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 1598 1599 /* 1600 * Scan entries covered by the range. When working on the next 1601 * entry a restart need only re-loop on the current entry which 1602 * we have already locked, since 'next' may have changed. Also, 1603 * even though entry is safe, it may have been clipped so we 1604 * have to iterate forwards through the clip after sleeping. 1605 */ 1606 while (entry->next != &map->header && entry->next->start < end) { 1607 vm_map_entry_t next = entry->next; 1608 1609 if (flags & MAP_CLIP_NO_HOLES) { 1610 if (next->start > entry->end) { 1611 vm_map_unclip_range(map, start_entry, 1612 start, entry->end, countp, flags); 1613 return(NULL); 1614 } 1615 } 1616 1617 if (next->eflags & MAP_ENTRY_IN_TRANSITION) { 1618 vm_offset_t save_end = entry->end; 1619 next->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1620 ++mycpu->gd_cnt.v_intrans_coll; 1621 ++mycpu->gd_cnt.v_intrans_wait; 1622 vm_map_transition_wait(map); 1623 1624 /* 1625 * clips might have occured while we blocked. 1626 */ 1627 CLIP_CHECK_FWD(entry, save_end); 1628 CLIP_CHECK_BACK(start_entry, start); 1629 continue; 1630 } 1631 /* 1632 * No restart necessary even though clip_end may block, we 1633 * are holding the map lock. 1634 */ 1635 vm_map_clip_end(map, next, end, countp); 1636 next->eflags |= MAP_ENTRY_IN_TRANSITION; 1637 entry = next; 1638 } 1639 if (flags & MAP_CLIP_NO_HOLES) { 1640 if (entry->end != end) { 1641 vm_map_unclip_range(map, start_entry, 1642 start, entry->end, countp, flags); 1643 return(NULL); 1644 } 1645 } 1646 return(start_entry); 1647 } 1648 1649 /* 1650 * Undo the effect of vm_map_clip_range(). You should pass the same 1651 * flags and the same range that you passed to vm_map_clip_range(). 1652 * This code will clear the in-transition flag on the entries and 1653 * wake up anyone waiting. This code will also simplify the sequence 1654 * and attempt to merge it with entries before and after the sequence. 1655 * 1656 * The map must be locked on entry and will remain locked on return. 1657 * 1658 * Note that you should also pass the start_entry returned by 1659 * vm_map_clip_range(). However, if you block between the two calls 1660 * with the map unlocked please be aware that the start_entry may 1661 * have been clipped and you may need to scan it backwards to find 1662 * the entry corresponding with the original start address. You are 1663 * responsible for this, vm_map_unclip_range() expects the correct 1664 * start_entry to be passed to it and will KASSERT otherwise. 1665 */ 1666 static 1667 void 1668 vm_map_unclip_range(vm_map_t map, vm_map_entry_t start_entry, 1669 vm_offset_t start, vm_offset_t end, 1670 int *countp, int flags) 1671 { 1672 vm_map_entry_t entry; 1673 1674 entry = start_entry; 1675 1676 KASSERT(entry->start == start, ("unclip_range: illegal base entry")); 1677 while (entry != &map->header && entry->start < end) { 1678 KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION, 1679 ("in-transition flag not set during unclip on: %p", 1680 entry)); 1681 KASSERT(entry->end <= end, 1682 ("unclip_range: tail wasn't clipped")); 1683 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; 1684 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 1685 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 1686 wakeup(map); 1687 } 1688 entry = entry->next; 1689 } 1690 1691 /* 1692 * Simplification does not block so there is no restart case. 1693 */ 1694 entry = start_entry; 1695 while (entry != &map->header && entry->start < end) { 1696 vm_map_simplify_entry(map, entry, countp); 1697 entry = entry->next; 1698 } 1699 } 1700 1701 /* 1702 * Mark the given range as handled by a subordinate map. 1703 * 1704 * This range must have been created with vm_map_find(), and no other 1705 * operations may have been performed on this range prior to calling 1706 * vm_map_submap(). 1707 * 1708 * Submappings cannot be removed. 1709 * 1710 * No requirements. 1711 */ 1712 int 1713 vm_map_submap(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_map_t submap) 1714 { 1715 vm_map_entry_t entry; 1716 int result = KERN_INVALID_ARGUMENT; 1717 int count; 1718 1719 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1720 vm_map_lock(map); 1721 1722 VM_MAP_RANGE_CHECK(map, start, end); 1723 1724 if (vm_map_lookup_entry(map, start, &entry)) { 1725 vm_map_clip_start(map, entry, start, &count); 1726 } else { 1727 entry = entry->next; 1728 } 1729 1730 vm_map_clip_end(map, entry, end, &count); 1731 1732 if ((entry->start == start) && (entry->end == end) && 1733 ((entry->eflags & MAP_ENTRY_COW) == 0) && 1734 (entry->object.vm_object == NULL)) { 1735 entry->object.sub_map = submap; 1736 entry->maptype = VM_MAPTYPE_SUBMAP; 1737 result = KERN_SUCCESS; 1738 } 1739 vm_map_unlock(map); 1740 vm_map_entry_release(count); 1741 1742 return (result); 1743 } 1744 1745 /* 1746 * Sets the protection of the specified address region in the target map. 1747 * If "set_max" is specified, the maximum protection is to be set; 1748 * otherwise, only the current protection is affected. 1749 * 1750 * The protection is not applicable to submaps, but is applicable to normal 1751 * maps and maps governed by virtual page tables. For example, when operating 1752 * on a virtual page table our protection basically controls how COW occurs 1753 * on the backing object, whereas the virtual page table abstraction itself 1754 * is an abstraction for userland. 1755 * 1756 * No requirements. 1757 */ 1758 int 1759 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, 1760 vm_prot_t new_prot, boolean_t set_max) 1761 { 1762 vm_map_entry_t current; 1763 vm_map_entry_t entry; 1764 int count; 1765 1766 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1767 vm_map_lock(map); 1768 1769 VM_MAP_RANGE_CHECK(map, start, end); 1770 1771 if (vm_map_lookup_entry(map, start, &entry)) { 1772 vm_map_clip_start(map, entry, start, &count); 1773 } else { 1774 entry = entry->next; 1775 } 1776 1777 /* 1778 * Make a first pass to check for protection violations. 1779 */ 1780 current = entry; 1781 while ((current != &map->header) && (current->start < end)) { 1782 if (current->maptype == VM_MAPTYPE_SUBMAP) { 1783 vm_map_unlock(map); 1784 vm_map_entry_release(count); 1785 return (KERN_INVALID_ARGUMENT); 1786 } 1787 if ((new_prot & current->max_protection) != new_prot) { 1788 vm_map_unlock(map); 1789 vm_map_entry_release(count); 1790 return (KERN_PROTECTION_FAILURE); 1791 } 1792 current = current->next; 1793 } 1794 1795 /* 1796 * Go back and fix up protections. [Note that clipping is not 1797 * necessary the second time.] 1798 */ 1799 current = entry; 1800 1801 while ((current != &map->header) && (current->start < end)) { 1802 vm_prot_t old_prot; 1803 1804 vm_map_clip_end(map, current, end, &count); 1805 1806 old_prot = current->protection; 1807 if (set_max) { 1808 current->protection = 1809 (current->max_protection = new_prot) & 1810 old_prot; 1811 } else { 1812 current->protection = new_prot; 1813 } 1814 1815 /* 1816 * Update physical map if necessary. Worry about copy-on-write 1817 * here -- CHECK THIS XXX 1818 */ 1819 1820 if (current->protection != old_prot) { 1821 #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ 1822 VM_PROT_ALL) 1823 1824 pmap_protect(map->pmap, current->start, 1825 current->end, 1826 current->protection & MASK(current)); 1827 #undef MASK 1828 } 1829 1830 vm_map_simplify_entry(map, current, &count); 1831 1832 current = current->next; 1833 } 1834 1835 vm_map_unlock(map); 1836 vm_map_entry_release(count); 1837 return (KERN_SUCCESS); 1838 } 1839 1840 /* 1841 * This routine traverses a processes map handling the madvise 1842 * system call. Advisories are classified as either those effecting 1843 * the vm_map_entry structure, or those effecting the underlying 1844 * objects. 1845 * 1846 * The <value> argument is used for extended madvise calls. 1847 * 1848 * No requirements. 1849 */ 1850 int 1851 vm_map_madvise(vm_map_t map, vm_offset_t start, vm_offset_t end, 1852 int behav, off_t value) 1853 { 1854 vm_map_entry_t current, entry; 1855 int modify_map = 0; 1856 int error = 0; 1857 int count; 1858 1859 /* 1860 * Some madvise calls directly modify the vm_map_entry, in which case 1861 * we need to use an exclusive lock on the map and we need to perform 1862 * various clipping operations. Otherwise we only need a read-lock 1863 * on the map. 1864 */ 1865 1866 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1867 1868 switch(behav) { 1869 case MADV_NORMAL: 1870 case MADV_SEQUENTIAL: 1871 case MADV_RANDOM: 1872 case MADV_NOSYNC: 1873 case MADV_AUTOSYNC: 1874 case MADV_NOCORE: 1875 case MADV_CORE: 1876 case MADV_SETMAP: 1877 case MADV_INVAL: 1878 modify_map = 1; 1879 vm_map_lock(map); 1880 break; 1881 case MADV_WILLNEED: 1882 case MADV_DONTNEED: 1883 case MADV_FREE: 1884 vm_map_lock_read(map); 1885 break; 1886 default: 1887 vm_map_entry_release(count); 1888 return (EINVAL); 1889 } 1890 1891 /* 1892 * Locate starting entry and clip if necessary. 1893 */ 1894 1895 VM_MAP_RANGE_CHECK(map, start, end); 1896 1897 if (vm_map_lookup_entry(map, start, &entry)) { 1898 if (modify_map) 1899 vm_map_clip_start(map, entry, start, &count); 1900 } else { 1901 entry = entry->next; 1902 } 1903 1904 if (modify_map) { 1905 /* 1906 * madvise behaviors that are implemented in the vm_map_entry. 1907 * 1908 * We clip the vm_map_entry so that behavioral changes are 1909 * limited to the specified address range. 1910 */ 1911 for (current = entry; 1912 (current != &map->header) && (current->start < end); 1913 current = current->next 1914 ) { 1915 if (current->maptype == VM_MAPTYPE_SUBMAP) 1916 continue; 1917 1918 vm_map_clip_end(map, current, end, &count); 1919 1920 switch (behav) { 1921 case MADV_NORMAL: 1922 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); 1923 break; 1924 case MADV_SEQUENTIAL: 1925 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); 1926 break; 1927 case MADV_RANDOM: 1928 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); 1929 break; 1930 case MADV_NOSYNC: 1931 current->eflags |= MAP_ENTRY_NOSYNC; 1932 break; 1933 case MADV_AUTOSYNC: 1934 current->eflags &= ~MAP_ENTRY_NOSYNC; 1935 break; 1936 case MADV_NOCORE: 1937 current->eflags |= MAP_ENTRY_NOCOREDUMP; 1938 break; 1939 case MADV_CORE: 1940 current->eflags &= ~MAP_ENTRY_NOCOREDUMP; 1941 break; 1942 case MADV_INVAL: 1943 /* 1944 * Invalidate the related pmap entries, used 1945 * to flush portions of the real kernel's 1946 * pmap when the caller has removed or 1947 * modified existing mappings in a virtual 1948 * page table. 1949 */ 1950 pmap_remove(map->pmap, 1951 current->start, current->end); 1952 break; 1953 case MADV_SETMAP: 1954 /* 1955 * Set the page directory page for a map 1956 * governed by a virtual page table. Mark 1957 * the entry as being governed by a virtual 1958 * page table if it is not. 1959 * 1960 * XXX the page directory page is stored 1961 * in the avail_ssize field if the map_entry. 1962 * 1963 * XXX the map simplification code does not 1964 * compare this field so weird things may 1965 * happen if you do not apply this function 1966 * to the entire mapping governed by the 1967 * virtual page table. 1968 */ 1969 if (current->maptype != VM_MAPTYPE_VPAGETABLE) { 1970 error = EINVAL; 1971 break; 1972 } 1973 current->aux.master_pde = value; 1974 pmap_remove(map->pmap, 1975 current->start, current->end); 1976 break; 1977 default: 1978 error = EINVAL; 1979 break; 1980 } 1981 vm_map_simplify_entry(map, current, &count); 1982 } 1983 vm_map_unlock(map); 1984 } else { 1985 vm_pindex_t pindex; 1986 int count; 1987 1988 /* 1989 * madvise behaviors that are implemented in the underlying 1990 * vm_object. 1991 * 1992 * Since we don't clip the vm_map_entry, we have to clip 1993 * the vm_object pindex and count. 1994 * 1995 * NOTE! We currently do not support these functions on 1996 * virtual page tables. 1997 */ 1998 for (current = entry; 1999 (current != &map->header) && (current->start < end); 2000 current = current->next 2001 ) { 2002 vm_offset_t useStart; 2003 2004 if (current->maptype != VM_MAPTYPE_NORMAL) 2005 continue; 2006 2007 pindex = OFF_TO_IDX(current->offset); 2008 count = atop(current->end - current->start); 2009 useStart = current->start; 2010 2011 if (current->start < start) { 2012 pindex += atop(start - current->start); 2013 count -= atop(start - current->start); 2014 useStart = start; 2015 } 2016 if (current->end > end) 2017 count -= atop(current->end - end); 2018 2019 if (count <= 0) 2020 continue; 2021 2022 vm_object_madvise(current->object.vm_object, 2023 pindex, count, behav); 2024 2025 /* 2026 * Try to populate the page table. Mappings governed 2027 * by virtual page tables cannot be pre-populated 2028 * without a lot of work so don't try. 2029 */ 2030 if (behav == MADV_WILLNEED && 2031 current->maptype != VM_MAPTYPE_VPAGETABLE) { 2032 pmap_object_init_pt( 2033 map->pmap, 2034 useStart, 2035 current->protection, 2036 current->object.vm_object, 2037 pindex, 2038 (count << PAGE_SHIFT), 2039 MAP_PREFAULT_MADVISE 2040 ); 2041 } 2042 } 2043 vm_map_unlock_read(map); 2044 } 2045 vm_map_entry_release(count); 2046 return(error); 2047 } 2048 2049 2050 /* 2051 * Sets the inheritance of the specified address range in the target map. 2052 * Inheritance affects how the map will be shared with child maps at the 2053 * time of vm_map_fork. 2054 */ 2055 int 2056 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, 2057 vm_inherit_t new_inheritance) 2058 { 2059 vm_map_entry_t entry; 2060 vm_map_entry_t temp_entry; 2061 int count; 2062 2063 switch (new_inheritance) { 2064 case VM_INHERIT_NONE: 2065 case VM_INHERIT_COPY: 2066 case VM_INHERIT_SHARE: 2067 break; 2068 default: 2069 return (KERN_INVALID_ARGUMENT); 2070 } 2071 2072 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2073 vm_map_lock(map); 2074 2075 VM_MAP_RANGE_CHECK(map, start, end); 2076 2077 if (vm_map_lookup_entry(map, start, &temp_entry)) { 2078 entry = temp_entry; 2079 vm_map_clip_start(map, entry, start, &count); 2080 } else 2081 entry = temp_entry->next; 2082 2083 while ((entry != &map->header) && (entry->start < end)) { 2084 vm_map_clip_end(map, entry, end, &count); 2085 2086 entry->inheritance = new_inheritance; 2087 2088 vm_map_simplify_entry(map, entry, &count); 2089 2090 entry = entry->next; 2091 } 2092 vm_map_unlock(map); 2093 vm_map_entry_release(count); 2094 return (KERN_SUCCESS); 2095 } 2096 2097 /* 2098 * Implement the semantics of mlock 2099 */ 2100 int 2101 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, 2102 boolean_t new_pageable) 2103 { 2104 vm_map_entry_t entry; 2105 vm_map_entry_t start_entry; 2106 vm_offset_t end; 2107 int rv = KERN_SUCCESS; 2108 int count; 2109 2110 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2111 vm_map_lock(map); 2112 VM_MAP_RANGE_CHECK(map, start, real_end); 2113 end = real_end; 2114 2115 start_entry = vm_map_clip_range(map, start, end, &count, 2116 MAP_CLIP_NO_HOLES); 2117 if (start_entry == NULL) { 2118 vm_map_unlock(map); 2119 vm_map_entry_release(count); 2120 return (KERN_INVALID_ADDRESS); 2121 } 2122 2123 if (new_pageable == 0) { 2124 entry = start_entry; 2125 while ((entry != &map->header) && (entry->start < end)) { 2126 vm_offset_t save_start; 2127 vm_offset_t save_end; 2128 2129 /* 2130 * Already user wired or hard wired (trivial cases) 2131 */ 2132 if (entry->eflags & MAP_ENTRY_USER_WIRED) { 2133 entry = entry->next; 2134 continue; 2135 } 2136 if (entry->wired_count != 0) { 2137 entry->wired_count++; 2138 entry->eflags |= MAP_ENTRY_USER_WIRED; 2139 entry = entry->next; 2140 continue; 2141 } 2142 2143 /* 2144 * A new wiring requires instantiation of appropriate 2145 * management structures and the faulting in of the 2146 * page. 2147 */ 2148 if (entry->maptype != VM_MAPTYPE_SUBMAP) { 2149 int copyflag = entry->eflags & 2150 MAP_ENTRY_NEEDS_COPY; 2151 if (copyflag && ((entry->protection & 2152 VM_PROT_WRITE) != 0)) { 2153 vm_map_entry_shadow(entry, 0); 2154 } else if (entry->object.vm_object == NULL && 2155 !map->system_map) { 2156 vm_map_entry_allocate_object(entry); 2157 } 2158 } 2159 entry->wired_count++; 2160 entry->eflags |= MAP_ENTRY_USER_WIRED; 2161 2162 /* 2163 * Now fault in the area. Note that vm_fault_wire() 2164 * may release the map lock temporarily, it will be 2165 * relocked on return. The in-transition 2166 * flag protects the entries. 2167 */ 2168 save_start = entry->start; 2169 save_end = entry->end; 2170 rv = vm_fault_wire(map, entry, TRUE); 2171 if (rv) { 2172 CLIP_CHECK_BACK(entry, save_start); 2173 for (;;) { 2174 KASSERT(entry->wired_count == 1, ("bad wired_count on entry")); 2175 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2176 entry->wired_count = 0; 2177 if (entry->end == save_end) 2178 break; 2179 entry = entry->next; 2180 KASSERT(entry != &map->header, ("bad entry clip during backout")); 2181 } 2182 end = save_start; /* unwire the rest */ 2183 break; 2184 } 2185 /* 2186 * note that even though the entry might have been 2187 * clipped, the USER_WIRED flag we set prevents 2188 * duplication so we do not have to do a 2189 * clip check. 2190 */ 2191 entry = entry->next; 2192 } 2193 2194 /* 2195 * If we failed fall through to the unwiring section to 2196 * unwire what we had wired so far. 'end' has already 2197 * been adjusted. 2198 */ 2199 if (rv) 2200 new_pageable = 1; 2201 2202 /* 2203 * start_entry might have been clipped if we unlocked the 2204 * map and blocked. No matter how clipped it has gotten 2205 * there should be a fragment that is on our start boundary. 2206 */ 2207 CLIP_CHECK_BACK(start_entry, start); 2208 } 2209 2210 /* 2211 * Deal with the unwiring case. 2212 */ 2213 if (new_pageable) { 2214 /* 2215 * This is the unwiring case. We must first ensure that the 2216 * range to be unwired is really wired down. We know there 2217 * are no holes. 2218 */ 2219 entry = start_entry; 2220 while ((entry != &map->header) && (entry->start < end)) { 2221 if ((entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 2222 rv = KERN_INVALID_ARGUMENT; 2223 goto done; 2224 } 2225 KASSERT(entry->wired_count != 0, ("wired count was 0 with USER_WIRED set! %p", entry)); 2226 entry = entry->next; 2227 } 2228 2229 /* 2230 * Now decrement the wiring count for each region. If a region 2231 * becomes completely unwired, unwire its physical pages and 2232 * mappings. 2233 */ 2234 /* 2235 * The map entries are processed in a loop, checking to 2236 * make sure the entry is wired and asserting it has a wired 2237 * count. However, another loop was inserted more-or-less in 2238 * the middle of the unwiring path. This loop picks up the 2239 * "entry" loop variable from the first loop without first 2240 * setting it to start_entry. Naturally, the secound loop 2241 * is never entered and the pages backing the entries are 2242 * never unwired. This can lead to a leak of wired pages. 2243 */ 2244 entry = start_entry; 2245 while ((entry != &map->header) && (entry->start < end)) { 2246 KASSERT(entry->eflags & MAP_ENTRY_USER_WIRED, 2247 ("expected USER_WIRED on entry %p", entry)); 2248 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2249 entry->wired_count--; 2250 if (entry->wired_count == 0) 2251 vm_fault_unwire(map, entry); 2252 entry = entry->next; 2253 } 2254 } 2255 done: 2256 vm_map_unclip_range(map, start_entry, start, real_end, &count, 2257 MAP_CLIP_NO_HOLES); 2258 map->timestamp++; 2259 vm_map_unlock(map); 2260 vm_map_entry_release(count); 2261 return (rv); 2262 } 2263 2264 /* 2265 * Sets the pageability of the specified address range in the target map. 2266 * Regions specified as not pageable require locked-down physical 2267 * memory and physical page maps. 2268 * 2269 * The map must not be locked, but a reference must remain to the map 2270 * throughout the call. 2271 * 2272 * This function may be called via the zalloc path and must properly 2273 * reserve map entries for kernel_map. 2274 * 2275 * No requirements. 2276 */ 2277 int 2278 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, int kmflags) 2279 { 2280 vm_map_entry_t entry; 2281 vm_map_entry_t start_entry; 2282 vm_offset_t end; 2283 int rv = KERN_SUCCESS; 2284 int count; 2285 2286 if (kmflags & KM_KRESERVE) 2287 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); 2288 else 2289 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2290 vm_map_lock(map); 2291 VM_MAP_RANGE_CHECK(map, start, real_end); 2292 end = real_end; 2293 2294 start_entry = vm_map_clip_range(map, start, end, &count, 2295 MAP_CLIP_NO_HOLES); 2296 if (start_entry == NULL) { 2297 vm_map_unlock(map); 2298 rv = KERN_INVALID_ADDRESS; 2299 goto failure; 2300 } 2301 if ((kmflags & KM_PAGEABLE) == 0) { 2302 /* 2303 * Wiring. 2304 * 2305 * 1. Holding the write lock, we create any shadow or zero-fill 2306 * objects that need to be created. Then we clip each map 2307 * entry to the region to be wired and increment its wiring 2308 * count. We create objects before clipping the map entries 2309 * to avoid object proliferation. 2310 * 2311 * 2. We downgrade to a read lock, and call vm_fault_wire to 2312 * fault in the pages for any newly wired area (wired_count is 2313 * 1). 2314 * 2315 * Downgrading to a read lock for vm_fault_wire avoids a 2316 * possible deadlock with another process that may have faulted 2317 * on one of the pages to be wired (it would mark the page busy, 2318 * blocking us, then in turn block on the map lock that we 2319 * hold). Because of problems in the recursive lock package, 2320 * we cannot upgrade to a write lock in vm_map_lookup. Thus, 2321 * any actions that require the write lock must be done 2322 * beforehand. Because we keep the read lock on the map, the 2323 * copy-on-write status of the entries we modify here cannot 2324 * change. 2325 */ 2326 entry = start_entry; 2327 while ((entry != &map->header) && (entry->start < end)) { 2328 /* 2329 * Trivial case if the entry is already wired 2330 */ 2331 if (entry->wired_count) { 2332 entry->wired_count++; 2333 entry = entry->next; 2334 continue; 2335 } 2336 2337 /* 2338 * The entry is being newly wired, we have to setup 2339 * appropriate management structures. A shadow 2340 * object is required for a copy-on-write region, 2341 * or a normal object for a zero-fill region. We 2342 * do not have to do this for entries that point to sub 2343 * maps because we won't hold the lock on the sub map. 2344 */ 2345 if (entry->maptype != VM_MAPTYPE_SUBMAP) { 2346 int copyflag = entry->eflags & 2347 MAP_ENTRY_NEEDS_COPY; 2348 if (copyflag && ((entry->protection & 2349 VM_PROT_WRITE) != 0)) { 2350 vm_map_entry_shadow(entry, 0); 2351 } else if (entry->object.vm_object == NULL && 2352 !map->system_map) { 2353 vm_map_entry_allocate_object(entry); 2354 } 2355 } 2356 2357 entry->wired_count++; 2358 entry = entry->next; 2359 } 2360 2361 /* 2362 * Pass 2. 2363 */ 2364 2365 /* 2366 * HACK HACK HACK HACK 2367 * 2368 * vm_fault_wire() temporarily unlocks the map to avoid 2369 * deadlocks. The in-transition flag from vm_map_clip_range 2370 * call should protect us from changes while the map is 2371 * unlocked. T 2372 * 2373 * NOTE: Previously this comment stated that clipping might 2374 * still occur while the entry is unlocked, but from 2375 * what I can tell it actually cannot. 2376 * 2377 * It is unclear whether the CLIP_CHECK_*() calls 2378 * are still needed but we keep them in anyway. 2379 * 2380 * HACK HACK HACK HACK 2381 */ 2382 2383 entry = start_entry; 2384 while (entry != &map->header && entry->start < end) { 2385 /* 2386 * If vm_fault_wire fails for any page we need to undo 2387 * what has been done. We decrement the wiring count 2388 * for those pages which have not yet been wired (now) 2389 * and unwire those that have (later). 2390 */ 2391 vm_offset_t save_start = entry->start; 2392 vm_offset_t save_end = entry->end; 2393 2394 if (entry->wired_count == 1) 2395 rv = vm_fault_wire(map, entry, FALSE); 2396 if (rv) { 2397 CLIP_CHECK_BACK(entry, save_start); 2398 for (;;) { 2399 KASSERT(entry->wired_count == 1, ("wired_count changed unexpectedly")); 2400 entry->wired_count = 0; 2401 if (entry->end == save_end) 2402 break; 2403 entry = entry->next; 2404 KASSERT(entry != &map->header, ("bad entry clip during backout")); 2405 } 2406 end = save_start; 2407 break; 2408 } 2409 CLIP_CHECK_FWD(entry, save_end); 2410 entry = entry->next; 2411 } 2412 2413 /* 2414 * If a failure occured undo everything by falling through 2415 * to the unwiring code. 'end' has already been adjusted 2416 * appropriately. 2417 */ 2418 if (rv) 2419 kmflags |= KM_PAGEABLE; 2420 2421 /* 2422 * start_entry is still IN_TRANSITION but may have been 2423 * clipped since vm_fault_wire() unlocks and relocks the 2424 * map. No matter how clipped it has gotten there should 2425 * be a fragment that is on our start boundary. 2426 */ 2427 CLIP_CHECK_BACK(start_entry, start); 2428 } 2429 2430 if (kmflags & KM_PAGEABLE) { 2431 /* 2432 * This is the unwiring case. We must first ensure that the 2433 * range to be unwired is really wired down. We know there 2434 * are no holes. 2435 */ 2436 entry = start_entry; 2437 while ((entry != &map->header) && (entry->start < end)) { 2438 if (entry->wired_count == 0) { 2439 rv = KERN_INVALID_ARGUMENT; 2440 goto done; 2441 } 2442 entry = entry->next; 2443 } 2444 2445 /* 2446 * Now decrement the wiring count for each region. If a region 2447 * becomes completely unwired, unwire its physical pages and 2448 * mappings. 2449 */ 2450 entry = start_entry; 2451 while ((entry != &map->header) && (entry->start < end)) { 2452 entry->wired_count--; 2453 if (entry->wired_count == 0) 2454 vm_fault_unwire(map, entry); 2455 entry = entry->next; 2456 } 2457 } 2458 done: 2459 vm_map_unclip_range(map, start_entry, start, real_end, 2460 &count, MAP_CLIP_NO_HOLES); 2461 map->timestamp++; 2462 vm_map_unlock(map); 2463 failure: 2464 if (kmflags & KM_KRESERVE) 2465 vm_map_entry_krelease(count); 2466 else 2467 vm_map_entry_release(count); 2468 return (rv); 2469 } 2470 2471 /* 2472 * Mark a newly allocated address range as wired but do not fault in 2473 * the pages. The caller is expected to load the pages into the object. 2474 * 2475 * The map must be locked on entry and will remain locked on return. 2476 * No other requirements. 2477 */ 2478 void 2479 vm_map_set_wired_quick(vm_map_t map, vm_offset_t addr, vm_size_t size, 2480 int *countp) 2481 { 2482 vm_map_entry_t scan; 2483 vm_map_entry_t entry; 2484 2485 entry = vm_map_clip_range(map, addr, addr + size, 2486 countp, MAP_CLIP_NO_HOLES); 2487 for (scan = entry; 2488 scan != &map->header && scan->start < addr + size; 2489 scan = scan->next) { 2490 KKASSERT(entry->wired_count == 0); 2491 entry->wired_count = 1; 2492 } 2493 vm_map_unclip_range(map, entry, addr, addr + size, 2494 countp, MAP_CLIP_NO_HOLES); 2495 } 2496 2497 /* 2498 * Push any dirty cached pages in the address range to their pager. 2499 * If syncio is TRUE, dirty pages are written synchronously. 2500 * If invalidate is TRUE, any cached pages are freed as well. 2501 * 2502 * This routine is called by sys_msync() 2503 * 2504 * Returns an error if any part of the specified range is not mapped. 2505 * 2506 * No requirements. 2507 */ 2508 int 2509 vm_map_clean(vm_map_t map, vm_offset_t start, vm_offset_t end, 2510 boolean_t syncio, boolean_t invalidate) 2511 { 2512 vm_map_entry_t current; 2513 vm_map_entry_t entry; 2514 vm_size_t size; 2515 vm_object_t object; 2516 vm_object_t tobj; 2517 vm_ooffset_t offset; 2518 2519 vm_map_lock_read(map); 2520 VM_MAP_RANGE_CHECK(map, start, end); 2521 if (!vm_map_lookup_entry(map, start, &entry)) { 2522 vm_map_unlock_read(map); 2523 return (KERN_INVALID_ADDRESS); 2524 } 2525 lwkt_gettoken(&map->token); 2526 2527 /* 2528 * Make a first pass to check for holes. 2529 */ 2530 for (current = entry; current->start < end; current = current->next) { 2531 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2532 lwkt_reltoken(&map->token); 2533 vm_map_unlock_read(map); 2534 return (KERN_INVALID_ARGUMENT); 2535 } 2536 if (end > current->end && 2537 (current->next == &map->header || 2538 current->end != current->next->start)) { 2539 lwkt_reltoken(&map->token); 2540 vm_map_unlock_read(map); 2541 return (KERN_INVALID_ADDRESS); 2542 } 2543 } 2544 2545 if (invalidate) 2546 pmap_remove(vm_map_pmap(map), start, end); 2547 2548 /* 2549 * Make a second pass, cleaning/uncaching pages from the indicated 2550 * objects as we go. 2551 */ 2552 for (current = entry; current->start < end; current = current->next) { 2553 offset = current->offset + (start - current->start); 2554 size = (end <= current->end ? end : current->end) - start; 2555 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2556 vm_map_t smap; 2557 vm_map_entry_t tentry; 2558 vm_size_t tsize; 2559 2560 smap = current->object.sub_map; 2561 vm_map_lock_read(smap); 2562 vm_map_lookup_entry(smap, offset, &tentry); 2563 tsize = tentry->end - offset; 2564 if (tsize < size) 2565 size = tsize; 2566 object = tentry->object.vm_object; 2567 offset = tentry->offset + (offset - tentry->start); 2568 vm_map_unlock_read(smap); 2569 } else { 2570 object = current->object.vm_object; 2571 } 2572 2573 if (object) 2574 vm_object_hold(object); 2575 2576 /* 2577 * Note that there is absolutely no sense in writing out 2578 * anonymous objects, so we track down the vnode object 2579 * to write out. 2580 * We invalidate (remove) all pages from the address space 2581 * anyway, for semantic correctness. 2582 * 2583 * note: certain anonymous maps, such as MAP_NOSYNC maps, 2584 * may start out with a NULL object. 2585 */ 2586 while (object && (tobj = object->backing_object) != NULL) { 2587 vm_object_hold(tobj); 2588 if (tobj == object->backing_object) { 2589 vm_object_lock_swap(); 2590 offset += object->backing_object_offset; 2591 vm_object_drop(object); 2592 object = tobj; 2593 if (object->size < OFF_TO_IDX(offset + size)) 2594 size = IDX_TO_OFF(object->size) - 2595 offset; 2596 break; 2597 } 2598 vm_object_drop(tobj); 2599 } 2600 if (object && (object->type == OBJT_VNODE) && 2601 (current->protection & VM_PROT_WRITE) && 2602 (object->flags & OBJ_NOMSYNC) == 0) { 2603 /* 2604 * Flush pages if writing is allowed, invalidate them 2605 * if invalidation requested. Pages undergoing I/O 2606 * will be ignored by vm_object_page_remove(). 2607 * 2608 * We cannot lock the vnode and then wait for paging 2609 * to complete without deadlocking against vm_fault. 2610 * Instead we simply call vm_object_page_remove() and 2611 * allow it to block internally on a page-by-page 2612 * basis when it encounters pages undergoing async 2613 * I/O. 2614 */ 2615 int flags; 2616 2617 /* no chain wait needed for vnode objects */ 2618 vm_object_reference_locked(object); 2619 vn_lock(object->handle, LK_EXCLUSIVE | LK_RETRY); 2620 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 2621 flags |= invalidate ? OBJPC_INVAL : 0; 2622 2623 /* 2624 * When operating on a virtual page table just 2625 * flush the whole object. XXX we probably ought 2626 * to 2627 */ 2628 switch(current->maptype) { 2629 case VM_MAPTYPE_NORMAL: 2630 vm_object_page_clean(object, 2631 OFF_TO_IDX(offset), 2632 OFF_TO_IDX(offset + size + PAGE_MASK), 2633 flags); 2634 break; 2635 case VM_MAPTYPE_VPAGETABLE: 2636 vm_object_page_clean(object, 0, 0, flags); 2637 break; 2638 } 2639 vn_unlock(((struct vnode *)object->handle)); 2640 vm_object_deallocate_locked(object); 2641 } 2642 if (object && invalidate && 2643 ((object->type == OBJT_VNODE) || 2644 (object->type == OBJT_DEVICE))) { 2645 int clean_only = 2646 (object->type == OBJT_DEVICE) ? FALSE : TRUE; 2647 /* no chain wait needed for vnode/device objects */ 2648 vm_object_reference_locked(object); 2649 switch(current->maptype) { 2650 case VM_MAPTYPE_NORMAL: 2651 vm_object_page_remove(object, 2652 OFF_TO_IDX(offset), 2653 OFF_TO_IDX(offset + size + PAGE_MASK), 2654 clean_only); 2655 break; 2656 case VM_MAPTYPE_VPAGETABLE: 2657 vm_object_page_remove(object, 0, 0, clean_only); 2658 break; 2659 } 2660 vm_object_deallocate_locked(object); 2661 } 2662 start += size; 2663 if (object) 2664 vm_object_drop(object); 2665 } 2666 2667 lwkt_reltoken(&map->token); 2668 vm_map_unlock_read(map); 2669 2670 return (KERN_SUCCESS); 2671 } 2672 2673 /* 2674 * Make the region specified by this entry pageable. 2675 * 2676 * The vm_map must be exclusively locked. 2677 */ 2678 static void 2679 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) 2680 { 2681 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2682 entry->wired_count = 0; 2683 vm_fault_unwire(map, entry); 2684 } 2685 2686 /* 2687 * Deallocate the given entry from the target map. 2688 * 2689 * The vm_map must be exclusively locked. 2690 */ 2691 static void 2692 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry, int *countp) 2693 { 2694 vm_map_entry_unlink(map, entry); 2695 map->size -= entry->end - entry->start; 2696 2697 switch(entry->maptype) { 2698 case VM_MAPTYPE_NORMAL: 2699 case VM_MAPTYPE_VPAGETABLE: 2700 vm_object_deallocate(entry->object.vm_object); 2701 break; 2702 default: 2703 break; 2704 } 2705 2706 vm_map_entry_dispose(map, entry, countp); 2707 } 2708 2709 /* 2710 * Deallocates the given address range from the target map. 2711 * 2712 * The vm_map must be exclusively locked. 2713 */ 2714 int 2715 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end, int *countp) 2716 { 2717 vm_object_t object; 2718 vm_map_entry_t entry; 2719 vm_map_entry_t first_entry; 2720 2721 ASSERT_VM_MAP_LOCKED(map); 2722 lwkt_gettoken(&map->token); 2723 again: 2724 /* 2725 * Find the start of the region, and clip it. Set entry to point 2726 * at the first record containing the requested address or, if no 2727 * such record exists, the next record with a greater address. The 2728 * loop will run from this point until a record beyond the termination 2729 * address is encountered. 2730 * 2731 * map->hint must be adjusted to not point to anything we delete, 2732 * so set it to the entry prior to the one being deleted. 2733 * 2734 * GGG see other GGG comment. 2735 */ 2736 if (vm_map_lookup_entry(map, start, &first_entry)) { 2737 entry = first_entry; 2738 vm_map_clip_start(map, entry, start, countp); 2739 map->hint = entry->prev; /* possible problem XXX */ 2740 } else { 2741 map->hint = first_entry; /* possible problem XXX */ 2742 entry = first_entry->next; 2743 } 2744 2745 /* 2746 * If a hole opens up prior to the current first_free then 2747 * adjust first_free. As with map->hint, map->first_free 2748 * cannot be left set to anything we might delete. 2749 */ 2750 if (entry == &map->header) { 2751 map->first_free = &map->header; 2752 } else if (map->first_free->start >= start) { 2753 map->first_free = entry->prev; 2754 } 2755 2756 /* 2757 * Step through all entries in this region 2758 */ 2759 while ((entry != &map->header) && (entry->start < end)) { 2760 vm_map_entry_t next; 2761 vm_offset_t s, e; 2762 vm_pindex_t offidxstart, offidxend, count; 2763 2764 /* 2765 * If we hit an in-transition entry we have to sleep and 2766 * retry. It's easier (and not really slower) to just retry 2767 * since this case occurs so rarely and the hint is already 2768 * pointing at the right place. We have to reset the 2769 * start offset so as not to accidently delete an entry 2770 * another process just created in vacated space. 2771 */ 2772 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 2773 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 2774 start = entry->start; 2775 ++mycpu->gd_cnt.v_intrans_coll; 2776 ++mycpu->gd_cnt.v_intrans_wait; 2777 vm_map_transition_wait(map); 2778 goto again; 2779 } 2780 vm_map_clip_end(map, entry, end, countp); 2781 2782 s = entry->start; 2783 e = entry->end; 2784 next = entry->next; 2785 2786 offidxstart = OFF_TO_IDX(entry->offset); 2787 count = OFF_TO_IDX(e - s); 2788 object = entry->object.vm_object; 2789 2790 /* 2791 * Unwire before removing addresses from the pmap; otherwise, 2792 * unwiring will put the entries back in the pmap. 2793 */ 2794 if (entry->wired_count != 0) 2795 vm_map_entry_unwire(map, entry); 2796 2797 offidxend = offidxstart + count; 2798 2799 if (object == &kernel_object) { 2800 vm_object_hold(object); 2801 vm_object_page_remove(object, offidxstart, 2802 offidxend, FALSE); 2803 vm_object_drop(object); 2804 } else if (object && object->type != OBJT_DEFAULT && 2805 object->type != OBJT_SWAP) { 2806 /* 2807 * vnode object routines cannot be chain-locked 2808 */ 2809 vm_object_hold(object); 2810 pmap_remove(map->pmap, s, e); 2811 vm_object_drop(object); 2812 } else if (object) { 2813 vm_object_hold(object); 2814 vm_object_chain_acquire(object); 2815 pmap_remove(map->pmap, s, e); 2816 2817 if (object != NULL && 2818 object->ref_count != 1 && 2819 (object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == 2820 OBJ_ONEMAPPING && 2821 (object->type == OBJT_DEFAULT || 2822 object->type == OBJT_SWAP)) { 2823 vm_object_collapse(object, NULL); 2824 vm_object_page_remove(object, offidxstart, 2825 offidxend, FALSE); 2826 if (object->type == OBJT_SWAP) { 2827 swap_pager_freespace(object, 2828 offidxstart, 2829 count); 2830 } 2831 if (offidxend >= object->size && 2832 offidxstart < object->size) { 2833 object->size = offidxstart; 2834 } 2835 } 2836 vm_object_chain_release(object); 2837 vm_object_drop(object); 2838 } 2839 2840 /* 2841 * Delete the entry (which may delete the object) only after 2842 * removing all pmap entries pointing to its pages. 2843 * (Otherwise, its page frames may be reallocated, and any 2844 * modify bits will be set in the wrong object!) 2845 */ 2846 vm_map_entry_delete(map, entry, countp); 2847 entry = next; 2848 } 2849 lwkt_reltoken(&map->token); 2850 return (KERN_SUCCESS); 2851 } 2852 2853 /* 2854 * Remove the given address range from the target map. 2855 * This is the exported form of vm_map_delete. 2856 * 2857 * No requirements. 2858 */ 2859 int 2860 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) 2861 { 2862 int result; 2863 int count; 2864 2865 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2866 vm_map_lock(map); 2867 VM_MAP_RANGE_CHECK(map, start, end); 2868 result = vm_map_delete(map, start, end, &count); 2869 vm_map_unlock(map); 2870 vm_map_entry_release(count); 2871 2872 return (result); 2873 } 2874 2875 /* 2876 * Assert that the target map allows the specified privilege on the 2877 * entire address region given. The entire region must be allocated. 2878 * 2879 * The caller must specify whether the vm_map is already locked or not. 2880 */ 2881 boolean_t 2882 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, 2883 vm_prot_t protection, boolean_t have_lock) 2884 { 2885 vm_map_entry_t entry; 2886 vm_map_entry_t tmp_entry; 2887 boolean_t result; 2888 2889 if (have_lock == FALSE) 2890 vm_map_lock_read(map); 2891 2892 if (!vm_map_lookup_entry(map, start, &tmp_entry)) { 2893 if (have_lock == FALSE) 2894 vm_map_unlock_read(map); 2895 return (FALSE); 2896 } 2897 entry = tmp_entry; 2898 2899 result = TRUE; 2900 while (start < end) { 2901 if (entry == &map->header) { 2902 result = FALSE; 2903 break; 2904 } 2905 /* 2906 * No holes allowed! 2907 */ 2908 2909 if (start < entry->start) { 2910 result = FALSE; 2911 break; 2912 } 2913 /* 2914 * Check protection associated with entry. 2915 */ 2916 2917 if ((entry->protection & protection) != protection) { 2918 result = FALSE; 2919 break; 2920 } 2921 /* go to next entry */ 2922 2923 start = entry->end; 2924 entry = entry->next; 2925 } 2926 if (have_lock == FALSE) 2927 vm_map_unlock_read(map); 2928 return (result); 2929 } 2930 2931 /* 2932 * If appropriate this function shadows the original object with a new object 2933 * and moves the VM pages from the original object to the new object. 2934 * The original object will also be collapsed, if possible. 2935 * 2936 * We can only do this for normal memory objects with a single mapping, and 2937 * it only makes sense to do it if there are 2 or more refs on the original 2938 * object. i.e. typically a memory object that has been extended into 2939 * multiple vm_map_entry's with non-overlapping ranges. 2940 * 2941 * This makes it easier to remove unused pages and keeps object inheritance 2942 * from being a negative impact on memory usage. 2943 * 2944 * On return the (possibly new) entry->object.vm_object will have an 2945 * additional ref on it for the caller to dispose of (usually by cloning 2946 * the vm_map_entry). The additional ref had to be done in this routine 2947 * to avoid racing a collapse. The object's ONEMAPPING flag will also be 2948 * cleared. 2949 * 2950 * The vm_map must be locked and its token held. 2951 */ 2952 static void 2953 vm_map_split(vm_map_entry_t entry) 2954 { 2955 #if 0 2956 /* UNOPTIMIZED */ 2957 vm_object_t oobject; 2958 2959 oobject = entry->object.vm_object; 2960 vm_object_hold(oobject); 2961 vm_object_chain_wait(oobject); 2962 vm_object_reference_locked(oobject); 2963 vm_object_clear_flag(oobject, OBJ_ONEMAPPING); 2964 vm_object_drop(oobject); 2965 #else 2966 /* OPTIMIZED */ 2967 vm_object_t oobject, nobject, bobject; 2968 vm_offset_t s, e; 2969 vm_page_t m; 2970 vm_pindex_t offidxstart, offidxend, idx; 2971 vm_size_t size; 2972 vm_ooffset_t offset; 2973 2974 /* 2975 * Setup. Chain lock the original object throughout the entire 2976 * routine to prevent new page faults from occuring. 2977 * 2978 * XXX can madvise WILLNEED interfere with us too? 2979 */ 2980 oobject = entry->object.vm_object; 2981 vm_object_hold(oobject); 2982 vm_object_chain_acquire(oobject); 2983 2984 /* 2985 * Original object cannot be split? 2986 */ 2987 if (oobject->handle == NULL || (oobject->type != OBJT_DEFAULT && 2988 oobject->type != OBJT_SWAP)) { 2989 vm_object_chain_release(oobject); 2990 vm_object_reference_locked(oobject); 2991 vm_object_clear_flag(oobject, OBJ_ONEMAPPING); 2992 vm_object_drop(oobject); 2993 return; 2994 } 2995 2996 /* 2997 * Collapse original object with its backing store as an 2998 * optimization to reduce chain lengths when possible. 2999 * 3000 * If ref_count <= 1 there aren't other non-overlapping vm_map_entry's 3001 * for oobject, so there's no point collapsing it. 3002 * 3003 * Then re-check whether the object can be split. 3004 */ 3005 vm_object_collapse(oobject, NULL); 3006 3007 if (oobject->ref_count <= 1 || 3008 (oobject->type != OBJT_DEFAULT && oobject->type != OBJT_SWAP) || 3009 (oobject->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) != OBJ_ONEMAPPING) { 3010 vm_object_chain_release(oobject); 3011 vm_object_reference_locked(oobject); 3012 vm_object_clear_flag(oobject, OBJ_ONEMAPPING); 3013 vm_object_drop(oobject); 3014 return; 3015 } 3016 3017 /* 3018 * Acquire the chain lock on the backing object. 3019 * 3020 * Give bobject an additional ref count for when it will be shadowed 3021 * by nobject. 3022 */ 3023 if ((bobject = oobject->backing_object) != NULL) { 3024 vm_object_hold(bobject); 3025 vm_object_chain_wait(bobject); 3026 vm_object_reference_locked(bobject); 3027 vm_object_chain_acquire(bobject); 3028 KKASSERT(bobject->backing_object == bobject); 3029 KKASSERT((bobject->flags & OBJ_DEAD) == 0); 3030 } 3031 3032 /* 3033 * Calculate the object page range and allocate the new object. 3034 */ 3035 offset = entry->offset; 3036 s = entry->start; 3037 e = entry->end; 3038 3039 offidxstart = OFF_TO_IDX(offset); 3040 offidxend = offidxstart + OFF_TO_IDX(e - s); 3041 size = offidxend - offidxstart; 3042 3043 switch(oobject->type) { 3044 case OBJT_DEFAULT: 3045 nobject = default_pager_alloc(NULL, IDX_TO_OFF(size), 3046 VM_PROT_ALL, 0); 3047 break; 3048 case OBJT_SWAP: 3049 nobject = swap_pager_alloc(NULL, IDX_TO_OFF(size), 3050 VM_PROT_ALL, 0); 3051 break; 3052 default: 3053 /* not reached */ 3054 nobject = NULL; 3055 KKASSERT(0); 3056 } 3057 3058 if (nobject == NULL) { 3059 if (bobject) { 3060 vm_object_chain_release(bobject); 3061 vm_object_deallocate(bobject); 3062 vm_object_drop(bobject); 3063 } 3064 vm_object_chain_release(oobject); 3065 vm_object_reference_locked(oobject); 3066 vm_object_clear_flag(oobject, OBJ_ONEMAPPING); 3067 vm_object_drop(oobject); 3068 return; 3069 } 3070 3071 /* 3072 * The new object will replace entry->object.vm_object so it needs 3073 * a second reference (the caller expects an additional ref). 3074 */ 3075 vm_object_hold(nobject); 3076 vm_object_reference_locked(nobject); 3077 vm_object_chain_acquire(nobject); 3078 3079 /* 3080 * nobject shadows bobject (oobject already shadows bobject). 3081 */ 3082 if (bobject) { 3083 nobject->backing_object_offset = 3084 oobject->backing_object_offset + IDX_TO_OFF(offidxstart); 3085 nobject->backing_object = bobject; 3086 bobject->shadow_count++; 3087 bobject->generation++; 3088 LIST_INSERT_HEAD(&bobject->shadow_head, nobject, shadow_list); 3089 vm_object_clear_flag(bobject, OBJ_ONEMAPPING); /* XXX? */ 3090 vm_object_chain_release(bobject); 3091 vm_object_drop(bobject); 3092 } 3093 3094 /* 3095 * Move the VM pages from oobject to nobject 3096 */ 3097 for (idx = 0; idx < size; idx++) { 3098 vm_page_t m; 3099 3100 m = vm_page_lookup_busy_wait(oobject, offidxstart + idx, 3101 TRUE, "vmpg"); 3102 if (m == NULL) 3103 continue; 3104 3105 /* 3106 * We must wait for pending I/O to complete before we can 3107 * rename the page. 3108 * 3109 * We do not have to VM_PROT_NONE the page as mappings should 3110 * not be changed by this operation. 3111 * 3112 * NOTE: The act of renaming a page updates chaingen for both 3113 * objects. 3114 */ 3115 vm_page_rename(m, nobject, idx); 3116 /* page automatically made dirty by rename and cache handled */ 3117 /* page remains busy */ 3118 } 3119 3120 if (oobject->type == OBJT_SWAP) { 3121 vm_object_pip_add(oobject, 1); 3122 /* 3123 * copy oobject pages into nobject and destroy unneeded 3124 * pages in shadow object. 3125 */ 3126 swap_pager_copy(oobject, nobject, offidxstart, 0); 3127 vm_object_pip_wakeup(oobject); 3128 } 3129 3130 /* 3131 * Wakeup the pages we played with. No spl protection is needed 3132 * for a simple wakeup. 3133 */ 3134 for (idx = 0; idx < size; idx++) { 3135 m = vm_page_lookup(nobject, idx); 3136 if (m) { 3137 KKASSERT(m->flags & PG_BUSY); 3138 vm_page_wakeup(m); 3139 } 3140 } 3141 entry->object.vm_object = nobject; 3142 entry->offset = 0LL; 3143 3144 /* 3145 * Cleanup 3146 * 3147 * NOTE: There is no need to remove OBJ_ONEMAPPING from oobject, the 3148 * related pages were moved and are no longer applicable to the 3149 * original object. 3150 * 3151 * NOTE: Deallocate oobject (due to its entry->object.vm_object being 3152 * replaced by nobject). 3153 */ 3154 vm_object_chain_release(nobject); 3155 vm_object_drop(nobject); 3156 if (bobject) { 3157 vm_object_chain_release(bobject); 3158 vm_object_drop(bobject); 3159 } 3160 vm_object_chain_release(oobject); 3161 /*vm_object_clear_flag(oobject, OBJ_ONEMAPPING);*/ 3162 vm_object_deallocate_locked(oobject); 3163 vm_object_drop(oobject); 3164 #endif 3165 } 3166 3167 /* 3168 * Copies the contents of the source entry to the destination 3169 * entry. The entries *must* be aligned properly. 3170 * 3171 * The vm_maps must be exclusively locked. 3172 * The vm_map's token must be held. 3173 * 3174 * Because the maps are locked no faults can be in progress during the 3175 * operation. 3176 */ 3177 static void 3178 vm_map_copy_entry(vm_map_t src_map, vm_map_t dst_map, 3179 vm_map_entry_t src_entry, vm_map_entry_t dst_entry) 3180 { 3181 vm_object_t src_object; 3182 3183 if (dst_entry->maptype == VM_MAPTYPE_SUBMAP) 3184 return; 3185 if (src_entry->maptype == VM_MAPTYPE_SUBMAP) 3186 return; 3187 3188 if (src_entry->wired_count == 0) { 3189 /* 3190 * If the source entry is marked needs_copy, it is already 3191 * write-protected. 3192 */ 3193 if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) { 3194 pmap_protect(src_map->pmap, 3195 src_entry->start, 3196 src_entry->end, 3197 src_entry->protection & ~VM_PROT_WRITE); 3198 } 3199 3200 /* 3201 * Make a copy of the object. 3202 * 3203 * The object must be locked prior to checking the object type 3204 * and for the call to vm_object_collapse() and vm_map_split(). 3205 * We cannot use *_hold() here because the split code will 3206 * probably try to destroy the object. The lock is a pool 3207 * token and doesn't care. 3208 * 3209 * We must bump src_map->timestamp when setting 3210 * MAP_ENTRY_NEEDS_COPY to force any concurrent fault 3211 * to retry, otherwise the concurrent fault might improperly 3212 * install a RW pte when its supposed to be a RO(COW) pte. 3213 * This race can occur because a vnode-backed fault may have 3214 * to temporarily release the map lock. 3215 */ 3216 if (src_entry->object.vm_object != NULL) { 3217 vm_map_split(src_entry); 3218 src_object = src_entry->object.vm_object; 3219 dst_entry->object.vm_object = src_object; 3220 src_entry->eflags |= (MAP_ENTRY_COW | 3221 MAP_ENTRY_NEEDS_COPY); 3222 dst_entry->eflags |= (MAP_ENTRY_COW | 3223 MAP_ENTRY_NEEDS_COPY); 3224 dst_entry->offset = src_entry->offset; 3225 ++src_map->timestamp; 3226 } else { 3227 dst_entry->object.vm_object = NULL; 3228 dst_entry->offset = 0; 3229 } 3230 3231 pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start, 3232 dst_entry->end - dst_entry->start, src_entry->start); 3233 } else { 3234 /* 3235 * Of course, wired down pages can't be set copy-on-write. 3236 * Cause wired pages to be copied into the new map by 3237 * simulating faults (the new pages are pageable) 3238 */ 3239 vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry); 3240 } 3241 } 3242 3243 /* 3244 * vmspace_fork: 3245 * Create a new process vmspace structure and vm_map 3246 * based on those of an existing process. The new map 3247 * is based on the old map, according to the inheritance 3248 * values on the regions in that map. 3249 * 3250 * The source map must not be locked. 3251 * No requirements. 3252 */ 3253 struct vmspace * 3254 vmspace_fork(struct vmspace *vm1) 3255 { 3256 struct vmspace *vm2; 3257 vm_map_t old_map = &vm1->vm_map; 3258 vm_map_t new_map; 3259 vm_map_entry_t old_entry; 3260 vm_map_entry_t new_entry; 3261 vm_object_t object; 3262 int count; 3263 3264 lwkt_gettoken(&vm1->vm_map.token); 3265 vm_map_lock(old_map); 3266 3267 /* 3268 * XXX Note: upcalls are not copied. 3269 */ 3270 vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset); 3271 lwkt_gettoken(&vm2->vm_map.token); 3272 bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy, 3273 (caddr_t)&vm1->vm_endcopy - (caddr_t)&vm1->vm_startcopy); 3274 new_map = &vm2->vm_map; /* XXX */ 3275 new_map->timestamp = 1; 3276 3277 vm_map_lock(new_map); 3278 3279 count = 0; 3280 old_entry = old_map->header.next; 3281 while (old_entry != &old_map->header) { 3282 ++count; 3283 old_entry = old_entry->next; 3284 } 3285 3286 count = vm_map_entry_reserve(count + MAP_RESERVE_COUNT); 3287 3288 old_entry = old_map->header.next; 3289 while (old_entry != &old_map->header) { 3290 if (old_entry->maptype == VM_MAPTYPE_SUBMAP) 3291 panic("vm_map_fork: encountered a submap"); 3292 3293 switch (old_entry->inheritance) { 3294 case VM_INHERIT_NONE: 3295 break; 3296 case VM_INHERIT_SHARE: 3297 /* 3298 * Clone the entry, creating the shared object if 3299 * necessary. 3300 */ 3301 if (old_entry->object.vm_object == NULL) 3302 vm_map_entry_allocate_object(old_entry); 3303 3304 if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3305 /* 3306 * Shadow a map_entry which needs a copy, 3307 * replacing its object with a new object 3308 * that points to the old one. Ask the 3309 * shadow code to automatically add an 3310 * additional ref. We can't do it afterwords 3311 * because we might race a collapse. The call 3312 * to vm_map_entry_shadow() will also clear 3313 * OBJ_ONEMAPPING. 3314 */ 3315 vm_map_entry_shadow(old_entry, 1); 3316 } else { 3317 /* 3318 * We will make a shared copy of the object, 3319 * and must clear OBJ_ONEMAPPING. 3320 * 3321 * XXX assert that object.vm_object != NULL 3322 * since we allocate it above. 3323 */ 3324 if (old_entry->object.vm_object) { 3325 object = old_entry->object.vm_object; 3326 vm_object_hold(object); 3327 vm_object_chain_wait(object); 3328 vm_object_reference_locked(object); 3329 vm_object_clear_flag(object, 3330 OBJ_ONEMAPPING); 3331 vm_object_drop(object); 3332 } 3333 } 3334 3335 /* 3336 * Clone the entry. We've already bumped the ref on 3337 * any vm_object. 3338 */ 3339 new_entry = vm_map_entry_create(new_map, &count); 3340 *new_entry = *old_entry; 3341 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3342 new_entry->wired_count = 0; 3343 3344 /* 3345 * Insert the entry into the new map -- we know we're 3346 * inserting at the end of the new map. 3347 */ 3348 3349 vm_map_entry_link(new_map, new_map->header.prev, 3350 new_entry); 3351 3352 /* 3353 * Update the physical map 3354 */ 3355 pmap_copy(new_map->pmap, old_map->pmap, 3356 new_entry->start, 3357 (old_entry->end - old_entry->start), 3358 old_entry->start); 3359 break; 3360 case VM_INHERIT_COPY: 3361 /* 3362 * Clone the entry and link into the map. 3363 */ 3364 new_entry = vm_map_entry_create(new_map, &count); 3365 *new_entry = *old_entry; 3366 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3367 new_entry->wired_count = 0; 3368 new_entry->object.vm_object = NULL; 3369 vm_map_entry_link(new_map, new_map->header.prev, 3370 new_entry); 3371 vm_map_copy_entry(old_map, new_map, old_entry, 3372 new_entry); 3373 break; 3374 } 3375 old_entry = old_entry->next; 3376 } 3377 3378 new_map->size = old_map->size; 3379 vm_map_unlock(old_map); 3380 vm_map_unlock(new_map); 3381 vm_map_entry_release(count); 3382 3383 lwkt_reltoken(&vm2->vm_map.token); 3384 lwkt_reltoken(&vm1->vm_map.token); 3385 3386 return (vm2); 3387 } 3388 3389 /* 3390 * Create an auto-grow stack entry 3391 * 3392 * No requirements. 3393 */ 3394 int 3395 vm_map_stack (vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, 3396 int flags, vm_prot_t prot, vm_prot_t max, int cow) 3397 { 3398 vm_map_entry_t prev_entry; 3399 vm_map_entry_t new_stack_entry; 3400 vm_size_t init_ssize; 3401 int rv; 3402 int count; 3403 vm_offset_t tmpaddr; 3404 3405 cow |= MAP_IS_STACK; 3406 3407 if (max_ssize < sgrowsiz) 3408 init_ssize = max_ssize; 3409 else 3410 init_ssize = sgrowsiz; 3411 3412 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3413 vm_map_lock(map); 3414 3415 /* 3416 * Find space for the mapping 3417 */ 3418 if ((flags & (MAP_FIXED | MAP_TRYFIXED)) == 0) { 3419 if (vm_map_findspace(map, addrbos, max_ssize, 1, 3420 flags, &tmpaddr)) { 3421 vm_map_unlock(map); 3422 vm_map_entry_release(count); 3423 return (KERN_NO_SPACE); 3424 } 3425 addrbos = tmpaddr; 3426 } 3427 3428 /* If addr is already mapped, no go */ 3429 if (vm_map_lookup_entry(map, addrbos, &prev_entry)) { 3430 vm_map_unlock(map); 3431 vm_map_entry_release(count); 3432 return (KERN_NO_SPACE); 3433 } 3434 3435 #if 0 3436 /* XXX already handled by kern_mmap() */ 3437 /* If we would blow our VMEM resource limit, no go */ 3438 if (map->size + init_ssize > 3439 curproc->p_rlimit[RLIMIT_VMEM].rlim_cur) { 3440 vm_map_unlock(map); 3441 vm_map_entry_release(count); 3442 return (KERN_NO_SPACE); 3443 } 3444 #endif 3445 3446 /* 3447 * If we can't accomodate max_ssize in the current mapping, 3448 * no go. However, we need to be aware that subsequent user 3449 * mappings might map into the space we have reserved for 3450 * stack, and currently this space is not protected. 3451 * 3452 * Hopefully we will at least detect this condition 3453 * when we try to grow the stack. 3454 */ 3455 if ((prev_entry->next != &map->header) && 3456 (prev_entry->next->start < addrbos + max_ssize)) { 3457 vm_map_unlock(map); 3458 vm_map_entry_release(count); 3459 return (KERN_NO_SPACE); 3460 } 3461 3462 /* 3463 * We initially map a stack of only init_ssize. We will 3464 * grow as needed later. Since this is to be a grow 3465 * down stack, we map at the top of the range. 3466 * 3467 * Note: we would normally expect prot and max to be 3468 * VM_PROT_ALL, and cow to be 0. Possibly we should 3469 * eliminate these as input parameters, and just 3470 * pass these values here in the insert call. 3471 */ 3472 rv = vm_map_insert(map, &count, 3473 NULL, 0, addrbos + max_ssize - init_ssize, 3474 addrbos + max_ssize, 3475 VM_MAPTYPE_NORMAL, 3476 prot, max, 3477 cow); 3478 3479 /* Now set the avail_ssize amount */ 3480 if (rv == KERN_SUCCESS) { 3481 if (prev_entry != &map->header) 3482 vm_map_clip_end(map, prev_entry, addrbos + max_ssize - init_ssize, &count); 3483 new_stack_entry = prev_entry->next; 3484 if (new_stack_entry->end != addrbos + max_ssize || 3485 new_stack_entry->start != addrbos + max_ssize - init_ssize) 3486 panic ("Bad entry start/end for new stack entry"); 3487 else 3488 new_stack_entry->aux.avail_ssize = max_ssize - init_ssize; 3489 } 3490 3491 vm_map_unlock(map); 3492 vm_map_entry_release(count); 3493 return (rv); 3494 } 3495 3496 /* 3497 * Attempts to grow a vm stack entry. Returns KERN_SUCCESS if the 3498 * desired address is already mapped, or if we successfully grow 3499 * the stack. Also returns KERN_SUCCESS if addr is outside the 3500 * stack range (this is strange, but preserves compatibility with 3501 * the grow function in vm_machdep.c). 3502 * 3503 * No requirements. 3504 */ 3505 int 3506 vm_map_growstack (struct proc *p, vm_offset_t addr) 3507 { 3508 vm_map_entry_t prev_entry; 3509 vm_map_entry_t stack_entry; 3510 vm_map_entry_t new_stack_entry; 3511 struct vmspace *vm = p->p_vmspace; 3512 vm_map_t map = &vm->vm_map; 3513 vm_offset_t end; 3514 int grow_amount; 3515 int rv = KERN_SUCCESS; 3516 int is_procstack; 3517 int use_read_lock = 1; 3518 int count; 3519 3520 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3521 Retry: 3522 if (use_read_lock) 3523 vm_map_lock_read(map); 3524 else 3525 vm_map_lock(map); 3526 3527 /* If addr is already in the entry range, no need to grow.*/ 3528 if (vm_map_lookup_entry(map, addr, &prev_entry)) 3529 goto done; 3530 3531 if ((stack_entry = prev_entry->next) == &map->header) 3532 goto done; 3533 if (prev_entry == &map->header) 3534 end = stack_entry->start - stack_entry->aux.avail_ssize; 3535 else 3536 end = prev_entry->end; 3537 3538 /* 3539 * This next test mimics the old grow function in vm_machdep.c. 3540 * It really doesn't quite make sense, but we do it anyway 3541 * for compatibility. 3542 * 3543 * If not growable stack, return success. This signals the 3544 * caller to proceed as he would normally with normal vm. 3545 */ 3546 if (stack_entry->aux.avail_ssize < 1 || 3547 addr >= stack_entry->start || 3548 addr < stack_entry->start - stack_entry->aux.avail_ssize) { 3549 goto done; 3550 } 3551 3552 /* Find the minimum grow amount */ 3553 grow_amount = roundup (stack_entry->start - addr, PAGE_SIZE); 3554 if (grow_amount > stack_entry->aux.avail_ssize) { 3555 rv = KERN_NO_SPACE; 3556 goto done; 3557 } 3558 3559 /* 3560 * If there is no longer enough space between the entries 3561 * nogo, and adjust the available space. Note: this 3562 * should only happen if the user has mapped into the 3563 * stack area after the stack was created, and is 3564 * probably an error. 3565 * 3566 * This also effectively destroys any guard page the user 3567 * might have intended by limiting the stack size. 3568 */ 3569 if (grow_amount > stack_entry->start - end) { 3570 if (use_read_lock && vm_map_lock_upgrade(map)) { 3571 /* lost lock */ 3572 use_read_lock = 0; 3573 goto Retry; 3574 } 3575 use_read_lock = 0; 3576 stack_entry->aux.avail_ssize = stack_entry->start - end; 3577 rv = KERN_NO_SPACE; 3578 goto done; 3579 } 3580 3581 is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr; 3582 3583 /* If this is the main process stack, see if we're over the 3584 * stack limit. 3585 */ 3586 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > 3587 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 3588 rv = KERN_NO_SPACE; 3589 goto done; 3590 } 3591 3592 /* Round up the grow amount modulo SGROWSIZ */ 3593 grow_amount = roundup (grow_amount, sgrowsiz); 3594 if (grow_amount > stack_entry->aux.avail_ssize) { 3595 grow_amount = stack_entry->aux.avail_ssize; 3596 } 3597 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > 3598 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 3599 grow_amount = p->p_rlimit[RLIMIT_STACK].rlim_cur - 3600 ctob(vm->vm_ssize); 3601 } 3602 3603 /* If we would blow our VMEM resource limit, no go */ 3604 if (map->size + grow_amount > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { 3605 rv = KERN_NO_SPACE; 3606 goto done; 3607 } 3608 3609 if (use_read_lock && vm_map_lock_upgrade(map)) { 3610 /* lost lock */ 3611 use_read_lock = 0; 3612 goto Retry; 3613 } 3614 use_read_lock = 0; 3615 3616 /* Get the preliminary new entry start value */ 3617 addr = stack_entry->start - grow_amount; 3618 3619 /* If this puts us into the previous entry, cut back our growth 3620 * to the available space. Also, see the note above. 3621 */ 3622 if (addr < end) { 3623 stack_entry->aux.avail_ssize = stack_entry->start - end; 3624 addr = end; 3625 } 3626 3627 rv = vm_map_insert(map, &count, 3628 NULL, 0, addr, stack_entry->start, 3629 VM_MAPTYPE_NORMAL, 3630 VM_PROT_ALL, VM_PROT_ALL, 3631 0); 3632 3633 /* Adjust the available stack space by the amount we grew. */ 3634 if (rv == KERN_SUCCESS) { 3635 if (prev_entry != &map->header) 3636 vm_map_clip_end(map, prev_entry, addr, &count); 3637 new_stack_entry = prev_entry->next; 3638 if (new_stack_entry->end != stack_entry->start || 3639 new_stack_entry->start != addr) 3640 panic ("Bad stack grow start/end in new stack entry"); 3641 else { 3642 new_stack_entry->aux.avail_ssize = 3643 stack_entry->aux.avail_ssize - 3644 (new_stack_entry->end - new_stack_entry->start); 3645 if (is_procstack) 3646 vm->vm_ssize += btoc(new_stack_entry->end - 3647 new_stack_entry->start); 3648 } 3649 3650 if (map->flags & MAP_WIREFUTURE) 3651 vm_map_unwire(map, new_stack_entry->start, 3652 new_stack_entry->end, FALSE); 3653 } 3654 3655 done: 3656 if (use_read_lock) 3657 vm_map_unlock_read(map); 3658 else 3659 vm_map_unlock(map); 3660 vm_map_entry_release(count); 3661 return (rv); 3662 } 3663 3664 /* 3665 * Unshare the specified VM space for exec. If other processes are 3666 * mapped to it, then create a new one. The new vmspace is null. 3667 * 3668 * No requirements. 3669 */ 3670 void 3671 vmspace_exec(struct proc *p, struct vmspace *vmcopy) 3672 { 3673 struct vmspace *oldvmspace = p->p_vmspace; 3674 struct vmspace *newvmspace; 3675 vm_map_t map = &p->p_vmspace->vm_map; 3676 3677 /* 3678 * If we are execing a resident vmspace we fork it, otherwise 3679 * we create a new vmspace. Note that exitingcnt and upcalls 3680 * are not copied to the new vmspace. 3681 */ 3682 lwkt_gettoken(&oldvmspace->vm_map.token); 3683 if (vmcopy) { 3684 newvmspace = vmspace_fork(vmcopy); 3685 lwkt_gettoken(&newvmspace->vm_map.token); 3686 } else { 3687 newvmspace = vmspace_alloc(map->min_offset, map->max_offset); 3688 lwkt_gettoken(&newvmspace->vm_map.token); 3689 bcopy(&oldvmspace->vm_startcopy, &newvmspace->vm_startcopy, 3690 (caddr_t)&oldvmspace->vm_endcopy - 3691 (caddr_t)&oldvmspace->vm_startcopy); 3692 } 3693 3694 /* 3695 * Finish initializing the vmspace before assigning it 3696 * to the process. The vmspace will become the current vmspace 3697 * if p == curproc. 3698 */ 3699 pmap_pinit2(vmspace_pmap(newvmspace)); 3700 pmap_replacevm(p, newvmspace, 0); 3701 lwkt_reltoken(&newvmspace->vm_map.token); 3702 lwkt_reltoken(&oldvmspace->vm_map.token); 3703 vmspace_free(oldvmspace); 3704 } 3705 3706 /* 3707 * Unshare the specified VM space for forcing COW. This 3708 * is called by rfork, for the (RFMEM|RFPROC) == 0 case. 3709 */ 3710 void 3711 vmspace_unshare(struct proc *p) 3712 { 3713 struct vmspace *oldvmspace = p->p_vmspace; 3714 struct vmspace *newvmspace; 3715 3716 lwkt_gettoken(&oldvmspace->vm_map.token); 3717 if (oldvmspace->vm_sysref.refcnt == 1) { 3718 lwkt_reltoken(&oldvmspace->vm_map.token); 3719 return; 3720 } 3721 newvmspace = vmspace_fork(oldvmspace); 3722 lwkt_gettoken(&newvmspace->vm_map.token); 3723 pmap_pinit2(vmspace_pmap(newvmspace)); 3724 pmap_replacevm(p, newvmspace, 0); 3725 lwkt_reltoken(&newvmspace->vm_map.token); 3726 lwkt_reltoken(&oldvmspace->vm_map.token); 3727 vmspace_free(oldvmspace); 3728 } 3729 3730 /* 3731 * vm_map_hint: return the beginning of the best area suitable for 3732 * creating a new mapping with "prot" protection. 3733 * 3734 * No requirements. 3735 */ 3736 vm_offset_t 3737 vm_map_hint(struct proc *p, vm_offset_t addr, vm_prot_t prot) 3738 { 3739 struct vmspace *vms = p->p_vmspace; 3740 3741 if (!randomize_mmap) { 3742 /* 3743 * Set a reasonable start point for the hint if it was 3744 * not specified or if it falls within the heap space. 3745 * Hinted mmap()s do not allocate out of the heap space. 3746 */ 3747 if (addr == 0 || 3748 (addr >= round_page((vm_offset_t)vms->vm_taddr) && 3749 addr < round_page((vm_offset_t)vms->vm_daddr + maxdsiz))) { 3750 addr = round_page((vm_offset_t)vms->vm_daddr + maxdsiz); 3751 } 3752 3753 return addr; 3754 } 3755 3756 if (addr != 0 && addr >= (vm_offset_t)vms->vm_daddr) 3757 return addr; 3758 3759 #ifdef notyet 3760 #ifdef __i386__ 3761 /* 3762 * If executable skip first two pages, otherwise start 3763 * after data + heap region. 3764 */ 3765 if ((prot & VM_PROT_EXECUTE) && 3766 ((vm_offset_t)vms->vm_daddr >= I386_MAX_EXE_ADDR)) { 3767 addr = (PAGE_SIZE * 2) + 3768 (karc4random() & (I386_MAX_EXE_ADDR / 2 - 1)); 3769 return (round_page(addr)); 3770 } 3771 #endif /* __i386__ */ 3772 #endif /* notyet */ 3773 3774 addr = (vm_offset_t)vms->vm_daddr + MAXDSIZ; 3775 addr += karc4random() & (MIN((256 * 1024 * 1024), MAXDSIZ) - 1); 3776 3777 return (round_page(addr)); 3778 } 3779 3780 /* 3781 * Finds the VM object, offset, and protection for a given virtual address 3782 * in the specified map, assuming a page fault of the type specified. 3783 * 3784 * Leaves the map in question locked for read; return values are guaranteed 3785 * until a vm_map_lookup_done call is performed. Note that the map argument 3786 * is in/out; the returned map must be used in the call to vm_map_lookup_done. 3787 * 3788 * A handle (out_entry) is returned for use in vm_map_lookup_done, to make 3789 * that fast. 3790 * 3791 * If a lookup is requested with "write protection" specified, the map may 3792 * be changed to perform virtual copying operations, although the data 3793 * referenced will remain the same. 3794 * 3795 * No requirements. 3796 */ 3797 int 3798 vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ 3799 vm_offset_t vaddr, 3800 vm_prot_t fault_typea, 3801 vm_map_entry_t *out_entry, /* OUT */ 3802 vm_object_t *object, /* OUT */ 3803 vm_pindex_t *pindex, /* OUT */ 3804 vm_prot_t *out_prot, /* OUT */ 3805 boolean_t *wired) /* OUT */ 3806 { 3807 vm_map_entry_t entry; 3808 vm_map_t map = *var_map; 3809 vm_prot_t prot; 3810 vm_prot_t fault_type = fault_typea; 3811 int use_read_lock = 1; 3812 int rv = KERN_SUCCESS; 3813 3814 RetryLookup: 3815 if (use_read_lock) 3816 vm_map_lock_read(map); 3817 else 3818 vm_map_lock(map); 3819 3820 /* 3821 * If the map has an interesting hint, try it before calling full 3822 * blown lookup routine. 3823 */ 3824 entry = map->hint; 3825 cpu_ccfence(); 3826 *out_entry = entry; 3827 *object = NULL; 3828 3829 if ((entry == &map->header) || 3830 (vaddr < entry->start) || (vaddr >= entry->end)) { 3831 vm_map_entry_t tmp_entry; 3832 3833 /* 3834 * Entry was either not a valid hint, or the vaddr was not 3835 * contained in the entry, so do a full lookup. 3836 */ 3837 if (!vm_map_lookup_entry(map, vaddr, &tmp_entry)) { 3838 rv = KERN_INVALID_ADDRESS; 3839 goto done; 3840 } 3841 3842 entry = tmp_entry; 3843 *out_entry = entry; 3844 } 3845 3846 /* 3847 * Handle submaps. 3848 */ 3849 if (entry->maptype == VM_MAPTYPE_SUBMAP) { 3850 vm_map_t old_map = map; 3851 3852 *var_map = map = entry->object.sub_map; 3853 if (use_read_lock) 3854 vm_map_unlock_read(old_map); 3855 else 3856 vm_map_unlock(old_map); 3857 use_read_lock = 1; 3858 goto RetryLookup; 3859 } 3860 3861 /* 3862 * Check whether this task is allowed to have this page. 3863 * Note the special case for MAP_ENTRY_COW 3864 * pages with an override. This is to implement a forced 3865 * COW for debuggers. 3866 */ 3867 3868 if (fault_type & VM_PROT_OVERRIDE_WRITE) 3869 prot = entry->max_protection; 3870 else 3871 prot = entry->protection; 3872 3873 fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 3874 if ((fault_type & prot) != fault_type) { 3875 rv = KERN_PROTECTION_FAILURE; 3876 goto done; 3877 } 3878 3879 if ((entry->eflags & MAP_ENTRY_USER_WIRED) && 3880 (entry->eflags & MAP_ENTRY_COW) && 3881 (fault_type & VM_PROT_WRITE) && 3882 (fault_typea & VM_PROT_OVERRIDE_WRITE) == 0) { 3883 rv = KERN_PROTECTION_FAILURE; 3884 goto done; 3885 } 3886 3887 /* 3888 * If this page is not pageable, we have to get it for all possible 3889 * accesses. 3890 */ 3891 *wired = (entry->wired_count != 0); 3892 if (*wired) 3893 prot = fault_type = entry->protection; 3894 3895 /* 3896 * Virtual page tables may need to update the accessed (A) bit 3897 * in a page table entry. Upgrade the fault to a write fault for 3898 * that case if the map will support it. If the map does not support 3899 * it the page table entry simply will not be updated. 3900 */ 3901 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 3902 if (prot & VM_PROT_WRITE) 3903 fault_type |= VM_PROT_WRITE; 3904 } 3905 3906 /* 3907 * If the entry was copy-on-write, we either ... 3908 */ 3909 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3910 /* 3911 * If we want to write the page, we may as well handle that 3912 * now since we've got the map locked. 3913 * 3914 * If we don't need to write the page, we just demote the 3915 * permissions allowed. 3916 */ 3917 3918 if (fault_type & VM_PROT_WRITE) { 3919 /* 3920 * Make a new object, and place it in the object 3921 * chain. Note that no new references have appeared 3922 * -- one just moved from the map to the new 3923 * object. 3924 */ 3925 3926 if (use_read_lock && vm_map_lock_upgrade(map)) { 3927 /* lost lock */ 3928 use_read_lock = 0; 3929 goto RetryLookup; 3930 } 3931 use_read_lock = 0; 3932 3933 vm_map_entry_shadow(entry, 0); 3934 } else { 3935 /* 3936 * We're attempting to read a copy-on-write page -- 3937 * don't allow writes. 3938 */ 3939 3940 prot &= ~VM_PROT_WRITE; 3941 } 3942 } 3943 3944 /* 3945 * Create an object if necessary. 3946 */ 3947 if (entry->object.vm_object == NULL && !map->system_map) { 3948 if (use_read_lock && vm_map_lock_upgrade(map)) { 3949 /* lost lock */ 3950 use_read_lock = 0; 3951 goto RetryLookup; 3952 } 3953 use_read_lock = 0; 3954 vm_map_entry_allocate_object(entry); 3955 } 3956 3957 /* 3958 * Return the object/offset from this entry. If the entry was 3959 * copy-on-write or empty, it has been fixed up. 3960 */ 3961 3962 *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); 3963 *object = entry->object.vm_object; 3964 3965 /* 3966 * Return whether this is the only map sharing this data. On 3967 * success we return with a read lock held on the map. On failure 3968 * we return with the map unlocked. 3969 */ 3970 *out_prot = prot; 3971 done: 3972 if (rv == KERN_SUCCESS) { 3973 if (use_read_lock == 0) 3974 vm_map_lock_downgrade(map); 3975 } else if (use_read_lock) { 3976 vm_map_unlock_read(map); 3977 } else { 3978 vm_map_unlock(map); 3979 } 3980 return (rv); 3981 } 3982 3983 /* 3984 * Releases locks acquired by a vm_map_lookup() 3985 * (according to the handle returned by that lookup). 3986 * 3987 * No other requirements. 3988 */ 3989 void 3990 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry, int count) 3991 { 3992 /* 3993 * Unlock the main-level map 3994 */ 3995 vm_map_unlock_read(map); 3996 if (count) 3997 vm_map_entry_release(count); 3998 } 3999 4000 #include "opt_ddb.h" 4001 #ifdef DDB 4002 #include <sys/kernel.h> 4003 4004 #include <ddb/ddb.h> 4005 4006 /* 4007 * Debugging only 4008 */ 4009 DB_SHOW_COMMAND(map, vm_map_print) 4010 { 4011 static int nlines; 4012 /* XXX convert args. */ 4013 vm_map_t map = (vm_map_t)addr; 4014 boolean_t full = have_addr; 4015 4016 vm_map_entry_t entry; 4017 4018 db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", 4019 (void *)map, 4020 (void *)map->pmap, map->nentries, map->timestamp); 4021 nlines++; 4022 4023 if (!full && db_indent) 4024 return; 4025 4026 db_indent += 2; 4027 for (entry = map->header.next; entry != &map->header; 4028 entry = entry->next) { 4029 db_iprintf("map entry %p: start=%p, end=%p\n", 4030 (void *)entry, (void *)entry->start, (void *)entry->end); 4031 nlines++; 4032 { 4033 static char *inheritance_name[4] = 4034 {"share", "copy", "none", "donate_copy"}; 4035 4036 db_iprintf(" prot=%x/%x/%s", 4037 entry->protection, 4038 entry->max_protection, 4039 inheritance_name[(int)(unsigned char)entry->inheritance]); 4040 if (entry->wired_count != 0) 4041 db_printf(", wired"); 4042 } 4043 if (entry->maptype == VM_MAPTYPE_SUBMAP) { 4044 /* XXX no %qd in kernel. Truncate entry->offset. */ 4045 db_printf(", share=%p, offset=0x%lx\n", 4046 (void *)entry->object.sub_map, 4047 (long)entry->offset); 4048 nlines++; 4049 if ((entry->prev == &map->header) || 4050 (entry->prev->object.sub_map != 4051 entry->object.sub_map)) { 4052 db_indent += 2; 4053 vm_map_print((db_expr_t)(intptr_t) 4054 entry->object.sub_map, 4055 full, 0, NULL); 4056 db_indent -= 2; 4057 } 4058 } else { 4059 /* XXX no %qd in kernel. Truncate entry->offset. */ 4060 db_printf(", object=%p, offset=0x%lx", 4061 (void *)entry->object.vm_object, 4062 (long)entry->offset); 4063 if (entry->eflags & MAP_ENTRY_COW) 4064 db_printf(", copy (%s)", 4065 (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); 4066 db_printf("\n"); 4067 nlines++; 4068 4069 if ((entry->prev == &map->header) || 4070 (entry->prev->object.vm_object != 4071 entry->object.vm_object)) { 4072 db_indent += 2; 4073 vm_object_print((db_expr_t)(intptr_t) 4074 entry->object.vm_object, 4075 full, 0, NULL); 4076 nlines += 4; 4077 db_indent -= 2; 4078 } 4079 } 4080 } 4081 db_indent -= 2; 4082 if (db_indent == 0) 4083 nlines = 0; 4084 } 4085 4086 /* 4087 * Debugging only 4088 */ 4089 DB_SHOW_COMMAND(procvm, procvm) 4090 { 4091 struct proc *p; 4092 4093 if (have_addr) { 4094 p = (struct proc *) addr; 4095 } else { 4096 p = curproc; 4097 } 4098 4099 db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", 4100 (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, 4101 (void *)vmspace_pmap(p->p_vmspace)); 4102 4103 vm_map_print((db_expr_t)(intptr_t)&p->p_vmspace->vm_map, 1, 0, NULL); 4104 } 4105 4106 #endif /* DDB */ 4107