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 * $DragonFly: src/sys/vm/vm_map.c,v 1.56 2007/04/29 18:25:41 dillon Exp $ 68 */ 69 70 /* 71 * Virtual memory mapping module. 72 */ 73 74 #include <sys/param.h> 75 #include <sys/systm.h> 76 #include <sys/kernel.h> 77 #include <sys/proc.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> 101 102 /* 103 * Virtual memory maps provide for the mapping, protection, and sharing 104 * of virtual memory objects. In addition, this module provides for an 105 * efficient virtual copy of memory from one map to another. 106 * 107 * Synchronization is required prior to most operations. 108 * 109 * Maps consist of an ordered doubly-linked list of simple entries. 110 * A hint and a RB tree is used to speed-up lookups. 111 * 112 * Callers looking to modify maps specify start/end addresses which cause 113 * the related map entry to be clipped if necessary, and then later 114 * recombined if the pieces remained compatible. 115 * 116 * Virtual copy operations are performed by copying VM object references 117 * from one map to another, and then marking both regions as copy-on-write. 118 */ 119 static void vmspace_terminate(struct vmspace *vm); 120 static void vmspace_lock(struct vmspace *vm); 121 static void vmspace_unlock(struct vmspace *vm); 122 static void vmspace_dtor(void *obj, void *private); 123 124 MALLOC_DEFINE(M_VMSPACE, "vmspace", "vmspace objcache backingstore"); 125 126 struct sysref_class vmspace_sysref_class = { 127 .name = "vmspace", 128 .mtype = M_VMSPACE, 129 .proto = SYSREF_PROTO_VMSPACE, 130 .offset = offsetof(struct vmspace, vm_sysref), 131 .objsize = sizeof(struct vmspace), 132 .mag_capacity = 32, 133 .flags = SRC_MANAGEDINIT, 134 .dtor = vmspace_dtor, 135 .ops = { 136 .terminate = (sysref_terminate_func_t)vmspace_terminate, 137 .lock = (sysref_lock_func_t)vmspace_lock, 138 .unlock = (sysref_lock_func_t)vmspace_unlock 139 } 140 }; 141 142 #define VMEPERCPU 2 143 144 static struct vm_zone mapentzone_store, mapzone_store; 145 static vm_zone_t mapentzone, mapzone; 146 static struct vm_object mapentobj, mapobj; 147 148 static struct vm_map_entry map_entry_init[MAX_MAPENT]; 149 static struct vm_map_entry cpu_map_entry_init[MAXCPU][VMEPERCPU]; 150 static struct vm_map map_init[MAX_KMAP]; 151 152 static void vm_map_entry_shadow(vm_map_entry_t entry); 153 static vm_map_entry_t vm_map_entry_create(vm_map_t map, int *); 154 static void vm_map_entry_dispose (vm_map_t map, vm_map_entry_t entry, int *); 155 static void _vm_map_clip_end (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 156 static void _vm_map_clip_start (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 157 static void vm_map_entry_delete (vm_map_t, vm_map_entry_t, int *); 158 static void vm_map_entry_unwire (vm_map_t, vm_map_entry_t); 159 static void vm_map_copy_entry (vm_map_t, vm_map_t, vm_map_entry_t, 160 vm_map_entry_t); 161 static void vm_map_split (vm_map_entry_t); 162 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); 163 164 /* 165 * Initialize the vm_map module. Must be called before any other vm_map 166 * routines. 167 * 168 * Map and entry structures are allocated from the general purpose 169 * memory pool with some exceptions: 170 * 171 * - The kernel map is allocated statically. 172 * - Initial kernel map entries are allocated out of a static pool. 173 * 174 * These restrictions are necessary since malloc() uses the 175 * maps and requires map entries. 176 * 177 * Called from the low level boot code only. 178 */ 179 void 180 vm_map_startup(void) 181 { 182 mapzone = &mapzone_store; 183 zbootinit(mapzone, "MAP", sizeof (struct vm_map), 184 map_init, MAX_KMAP); 185 mapentzone = &mapentzone_store; 186 zbootinit(mapentzone, "MAP ENTRY", sizeof (struct vm_map_entry), 187 map_entry_init, MAX_MAPENT); 188 } 189 190 /* 191 * Called prior to any vmspace allocations. 192 * 193 * Called from the low level boot code only. 194 */ 195 void 196 vm_init2(void) 197 { 198 zinitna(mapentzone, &mapentobj, NULL, 0, 0, 199 ZONE_USE_RESERVE | ZONE_SPECIAL, 1); 200 zinitna(mapzone, &mapobj, NULL, 0, 0, 0, 1); 201 pmap_init2(); 202 vm_object_init2(); 203 } 204 205 206 /* 207 * Red black tree functions 208 * 209 * The caller must hold the related map lock. 210 */ 211 static int rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b); 212 RB_GENERATE(vm_map_rb_tree, vm_map_entry, rb_entry, rb_vm_map_compare); 213 214 /* a->start is address, and the only field has to be initialized */ 215 static int 216 rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b) 217 { 218 if (a->start < b->start) 219 return(-1); 220 else if (a->start > b->start) 221 return(1); 222 return(0); 223 } 224 225 /* 226 * Allocate a vmspace structure, including a vm_map and pmap. 227 * Initialize numerous fields. While the initial allocation is zerod, 228 * subsequence reuse from the objcache leaves elements of the structure 229 * intact (particularly the pmap), so portions must be zerod. 230 * 231 * The structure is not considered activated until we call sysref_activate(). 232 * 233 * No requirements. 234 */ 235 struct vmspace * 236 vmspace_alloc(vm_offset_t min, vm_offset_t max) 237 { 238 struct vmspace *vm; 239 240 lwkt_gettoken(&vmspace_token); 241 vm = sysref_alloc(&vmspace_sysref_class); 242 bzero(&vm->vm_startcopy, 243 (char *)&vm->vm_endcopy - (char *)&vm->vm_startcopy); 244 vm_map_init(&vm->vm_map, min, max, NULL); 245 pmap_pinit(vmspace_pmap(vm)); /* (some fields reused) */ 246 vm->vm_map.pmap = vmspace_pmap(vm); /* XXX */ 247 vm->vm_shm = NULL; 248 vm->vm_exitingcnt = 0; 249 cpu_vmspace_alloc(vm); 250 sysref_activate(&vm->vm_sysref); 251 lwkt_reltoken(&vmspace_token); 252 253 return (vm); 254 } 255 256 /* 257 * dtor function - Some elements of the pmap are retained in the 258 * free-cached vmspaces to improve performance. We have to clean them up 259 * here before returning the vmspace to the memory pool. 260 * 261 * No requirements. 262 */ 263 static void 264 vmspace_dtor(void *obj, void *private) 265 { 266 struct vmspace *vm = obj; 267 268 pmap_puninit(vmspace_pmap(vm)); 269 } 270 271 /* 272 * Called in two cases: 273 * 274 * (1) When the last sysref is dropped, but exitingcnt might still be 275 * non-zero. 276 * 277 * (2) When there are no sysrefs (i.e. refcnt is negative) left and the 278 * exitingcnt becomes zero 279 * 280 * sysref will not scrap the object until we call sysref_put() once more 281 * after the last ref has been dropped. 282 * 283 * Interlocked by the sysref API. 284 */ 285 static void 286 vmspace_terminate(struct vmspace *vm) 287 { 288 int count; 289 290 /* 291 * If exitingcnt is non-zero we can't get rid of the entire vmspace 292 * yet, but we can scrap user memory. 293 */ 294 lwkt_gettoken(&vmspace_token); 295 if (vm->vm_exitingcnt) { 296 shmexit(vm); 297 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_USER_ADDRESS, 298 VM_MAX_USER_ADDRESS); 299 vm_map_remove(&vm->vm_map, VM_MIN_USER_ADDRESS, 300 VM_MAX_USER_ADDRESS); 301 lwkt_reltoken(&vmspace_token); 302 return; 303 } 304 cpu_vmspace_free(vm); 305 306 /* 307 * Make sure any SysV shm is freed, it might not have in 308 * exit1() 309 */ 310 shmexit(vm); 311 312 KKASSERT(vm->vm_upcalls == NULL); 313 314 /* 315 * Lock the map, to wait out all other references to it. 316 * Delete all of the mappings and pages they hold, then call 317 * the pmap module to reclaim anything left. 318 */ 319 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 320 vm_map_lock(&vm->vm_map); 321 vm_map_delete(&vm->vm_map, vm->vm_map.min_offset, 322 vm->vm_map.max_offset, &count); 323 vm_map_unlock(&vm->vm_map); 324 vm_map_entry_release(count); 325 326 pmap_release(vmspace_pmap(vm)); 327 sysref_put(&vm->vm_sysref); 328 lwkt_reltoken(&vmspace_token); 329 } 330 331 /* 332 * vmspaces are not currently locked. 333 */ 334 static void 335 vmspace_lock(struct vmspace *vm __unused) 336 { 337 } 338 339 static void 340 vmspace_unlock(struct vmspace *vm __unused) 341 { 342 } 343 344 /* 345 * This is called during exit indicating that the vmspace is no 346 * longer in used by an exiting process, but the process has not yet 347 * been cleaned up. 348 * 349 * No requirements. 350 */ 351 void 352 vmspace_exitbump(struct vmspace *vm) 353 { 354 lwkt_gettoken(&vmspace_token); 355 ++vm->vm_exitingcnt; 356 lwkt_reltoken(&vmspace_token); 357 } 358 359 /* 360 * This is called in the wait*() handling code. The vmspace can be terminated 361 * after the last wait is finished using it. 362 * 363 * No requirements. 364 */ 365 void 366 vmspace_exitfree(struct proc *p) 367 { 368 struct vmspace *vm; 369 370 lwkt_gettoken(&vmspace_token); 371 vm = p->p_vmspace; 372 p->p_vmspace = NULL; 373 374 if (--vm->vm_exitingcnt == 0 && sysref_isinactive(&vm->vm_sysref)) 375 vmspace_terminate(vm); 376 lwkt_reltoken(&vmspace_token); 377 } 378 379 /* 380 * Swap useage is determined by taking the proportional swap used by 381 * VM objects backing the VM map. To make up for fractional losses, 382 * if the VM object has any swap use at all the associated map entries 383 * count for at least 1 swap page. 384 * 385 * No requirements. 386 */ 387 int 388 vmspace_swap_count(struct vmspace *vmspace) 389 { 390 vm_map_t map = &vmspace->vm_map; 391 vm_map_entry_t cur; 392 vm_object_t object; 393 int count = 0; 394 int n; 395 396 lwkt_gettoken(&vmspace_token); 397 for (cur = map->header.next; cur != &map->header; cur = cur->next) { 398 switch(cur->maptype) { 399 case VM_MAPTYPE_NORMAL: 400 case VM_MAPTYPE_VPAGETABLE: 401 if ((object = cur->object.vm_object) == NULL) 402 break; 403 if (object->swblock_count) { 404 n = (cur->end - cur->start) / PAGE_SIZE; 405 count += object->swblock_count * 406 SWAP_META_PAGES * n / object->size + 1; 407 } 408 break; 409 default: 410 break; 411 } 412 } 413 lwkt_reltoken(&vmspace_token); 414 return(count); 415 } 416 417 /* 418 * Calculate the approximate number of anonymous pages in use by 419 * this vmspace. To make up for fractional losses, we count each 420 * VM object as having at least 1 anonymous page. 421 * 422 * No requirements. 423 */ 424 int 425 vmspace_anonymous_count(struct vmspace *vmspace) 426 { 427 vm_map_t map = &vmspace->vm_map; 428 vm_map_entry_t cur; 429 vm_object_t object; 430 int count = 0; 431 432 lwkt_gettoken(&vmspace_token); 433 for (cur = map->header.next; cur != &map->header; cur = cur->next) { 434 switch(cur->maptype) { 435 case VM_MAPTYPE_NORMAL: 436 case VM_MAPTYPE_VPAGETABLE: 437 if ((object = cur->object.vm_object) == NULL) 438 break; 439 if (object->type != OBJT_DEFAULT && 440 object->type != OBJT_SWAP) { 441 break; 442 } 443 count += object->resident_page_count; 444 break; 445 default: 446 break; 447 } 448 } 449 lwkt_reltoken(&vmspace_token); 450 return(count); 451 } 452 453 /* 454 * Creates and returns a new empty VM map with the given physical map 455 * structure, and having the given lower and upper address bounds. 456 * 457 * No requirements. 458 */ 459 vm_map_t 460 vm_map_create(vm_map_t result, pmap_t pmap, vm_offset_t min, vm_offset_t max) 461 { 462 if (result == NULL) 463 result = zalloc(mapzone); 464 vm_map_init(result, min, max, pmap); 465 return (result); 466 } 467 468 /* 469 * Initialize an existing vm_map structure such as that in the vmspace 470 * structure. The pmap is initialized elsewhere. 471 * 472 * No requirements. 473 */ 474 void 475 vm_map_init(struct vm_map *map, vm_offset_t min, vm_offset_t max, pmap_t pmap) 476 { 477 map->header.next = map->header.prev = &map->header; 478 RB_INIT(&map->rb_root); 479 map->nentries = 0; 480 map->size = 0; 481 map->system_map = 0; 482 map->infork = 0; 483 map->min_offset = min; 484 map->max_offset = max; 485 map->pmap = pmap; 486 map->first_free = &map->header; 487 map->hint = &map->header; 488 map->timestamp = 0; 489 lockinit(&map->lock, "thrd_sleep", 0, 0); 490 } 491 492 /* 493 * Shadow the vm_map_entry's object. This typically needs to be done when 494 * a write fault is taken on an entry which had previously been cloned by 495 * fork(). The shared object (which might be NULL) must become private so 496 * we add a shadow layer above it. 497 * 498 * Object allocation for anonymous mappings is defered as long as possible. 499 * When creating a shadow, however, the underlying object must be instantiated 500 * so it can be shared. 501 * 502 * If the map segment is governed by a virtual page table then it is 503 * possible to address offsets beyond the mapped area. Just allocate 504 * a maximally sized object for this case. 505 * 506 * The vm_map must be exclusively locked. 507 * No other requirements. 508 */ 509 static 510 void 511 vm_map_entry_shadow(vm_map_entry_t entry) 512 { 513 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 514 vm_object_shadow(&entry->object.vm_object, &entry->offset, 515 0x7FFFFFFF); /* XXX */ 516 } else { 517 vm_object_shadow(&entry->object.vm_object, &entry->offset, 518 atop(entry->end - entry->start)); 519 } 520 entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 521 } 522 523 /* 524 * Allocate an object for a vm_map_entry. 525 * 526 * Object allocation for anonymous mappings is defered as long as possible. 527 * This function is called when we can defer no longer, generally when a map 528 * entry might be split or forked or takes a page fault. 529 * 530 * If the map segment is governed by a virtual page table then it is 531 * possible to address offsets beyond the mapped area. Just allocate 532 * a maximally sized object for this case. 533 * 534 * The vm_map must be exclusively locked. 535 * No other requirements. 536 */ 537 void 538 vm_map_entry_allocate_object(vm_map_entry_t entry) 539 { 540 vm_object_t obj; 541 542 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 543 obj = vm_object_allocate(OBJT_DEFAULT, 0x7FFFFFFF); /* XXX */ 544 } else { 545 obj = vm_object_allocate(OBJT_DEFAULT, 546 atop(entry->end - entry->start)); 547 } 548 entry->object.vm_object = obj; 549 entry->offset = 0; 550 } 551 552 /* 553 * Set an initial negative count so the first attempt to reserve 554 * space preloads a bunch of vm_map_entry's for this cpu. Also 555 * pre-allocate 2 vm_map_entries which will be needed by zalloc() to 556 * map a new page for vm_map_entry structures. SMP systems are 557 * particularly sensitive. 558 * 559 * This routine is called in early boot so we cannot just call 560 * vm_map_entry_reserve(). 561 * 562 * Called from the low level boot code only (for each cpu) 563 */ 564 void 565 vm_map_entry_reserve_cpu_init(globaldata_t gd) 566 { 567 vm_map_entry_t entry; 568 int i; 569 570 gd->gd_vme_avail -= MAP_RESERVE_COUNT * 2; 571 entry = &cpu_map_entry_init[gd->gd_cpuid][0]; 572 for (i = 0; i < VMEPERCPU; ++i, ++entry) { 573 entry->next = gd->gd_vme_base; 574 gd->gd_vme_base = entry; 575 } 576 } 577 578 /* 579 * Reserves vm_map_entry structures so code later on can manipulate 580 * map_entry structures within a locked map without blocking trying 581 * to allocate a new vm_map_entry. 582 * 583 * No requirements. 584 */ 585 int 586 vm_map_entry_reserve(int count) 587 { 588 struct globaldata *gd = mycpu; 589 vm_map_entry_t entry; 590 591 /* 592 * Make sure we have enough structures in gd_vme_base to handle 593 * the reservation request. 594 */ 595 crit_enter(); 596 while (gd->gd_vme_avail < count) { 597 entry = zalloc(mapentzone); 598 entry->next = gd->gd_vme_base; 599 gd->gd_vme_base = entry; 600 ++gd->gd_vme_avail; 601 } 602 gd->gd_vme_avail -= count; 603 crit_exit(); 604 605 return(count); 606 } 607 608 /* 609 * Releases previously reserved vm_map_entry structures that were not 610 * used. If we have too much junk in our per-cpu cache clean some of 611 * it out. 612 * 613 * No requirements. 614 */ 615 void 616 vm_map_entry_release(int count) 617 { 618 struct globaldata *gd = mycpu; 619 vm_map_entry_t entry; 620 621 crit_enter(); 622 gd->gd_vme_avail += count; 623 while (gd->gd_vme_avail > MAP_RESERVE_SLOP) { 624 entry = gd->gd_vme_base; 625 KKASSERT(entry != NULL); 626 gd->gd_vme_base = entry->next; 627 --gd->gd_vme_avail; 628 crit_exit(); 629 zfree(mapentzone, entry); 630 crit_enter(); 631 } 632 crit_exit(); 633 } 634 635 /* 636 * Reserve map entry structures for use in kernel_map itself. These 637 * entries have *ALREADY* been reserved on a per-cpu basis when the map 638 * was inited. This function is used by zalloc() to avoid a recursion 639 * when zalloc() itself needs to allocate additional kernel memory. 640 * 641 * This function works like the normal reserve but does not load the 642 * vm_map_entry cache (because that would result in an infinite 643 * recursion). Note that gd_vme_avail may go negative. This is expected. 644 * 645 * Any caller of this function must be sure to renormalize after 646 * potentially eating entries to ensure that the reserve supply 647 * remains intact. 648 * 649 * No requirements. 650 */ 651 int 652 vm_map_entry_kreserve(int count) 653 { 654 struct globaldata *gd = mycpu; 655 656 crit_enter(); 657 gd->gd_vme_avail -= count; 658 crit_exit(); 659 KASSERT(gd->gd_vme_base != NULL, 660 ("no reserved entries left, gd_vme_avail = %d\n", 661 gd->gd_vme_avail)); 662 return(count); 663 } 664 665 /* 666 * Release previously reserved map entries for kernel_map. We do not 667 * attempt to clean up like the normal release function as this would 668 * cause an unnecessary (but probably not fatal) deep procedure call. 669 * 670 * No requirements. 671 */ 672 void 673 vm_map_entry_krelease(int count) 674 { 675 struct globaldata *gd = mycpu; 676 677 crit_enter(); 678 gd->gd_vme_avail += count; 679 crit_exit(); 680 } 681 682 /* 683 * Allocates a VM map entry for insertion. No entry fields are filled in. 684 * 685 * The entries should have previously been reserved. The reservation count 686 * is tracked in (*countp). 687 * 688 * No requirements. 689 */ 690 static vm_map_entry_t 691 vm_map_entry_create(vm_map_t map, int *countp) 692 { 693 struct globaldata *gd = mycpu; 694 vm_map_entry_t entry; 695 696 KKASSERT(*countp > 0); 697 --*countp; 698 crit_enter(); 699 entry = gd->gd_vme_base; 700 KASSERT(entry != NULL, ("gd_vme_base NULL! count %d", *countp)); 701 gd->gd_vme_base = entry->next; 702 crit_exit(); 703 704 return(entry); 705 } 706 707 /* 708 * Dispose of a vm_map_entry that is no longer being referenced. 709 * 710 * No requirements. 711 */ 712 static void 713 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry, int *countp) 714 { 715 struct globaldata *gd = mycpu; 716 717 KKASSERT(map->hint != entry); 718 KKASSERT(map->first_free != entry); 719 720 ++*countp; 721 crit_enter(); 722 entry->next = gd->gd_vme_base; 723 gd->gd_vme_base = entry; 724 crit_exit(); 725 } 726 727 728 /* 729 * Insert/remove entries from maps. 730 * 731 * The related map must be exclusively locked. 732 * No other requirements. 733 * 734 * NOTE! We currently acquire the vmspace_token only to avoid races 735 * against the pageout daemon's calls to vmspace_*_count(), which 736 * are unable to safely lock the vm_map without potentially 737 * deadlocking. 738 */ 739 static __inline void 740 vm_map_entry_link(vm_map_t map, 741 vm_map_entry_t after_where, 742 vm_map_entry_t entry) 743 { 744 ASSERT_VM_MAP_LOCKED(map); 745 746 lwkt_gettoken(&vmspace_token); 747 map->nentries++; 748 entry->prev = after_where; 749 entry->next = after_where->next; 750 entry->next->prev = entry; 751 after_where->next = entry; 752 if (vm_map_rb_tree_RB_INSERT(&map->rb_root, entry)) 753 panic("vm_map_entry_link: dup addr map %p ent %p", map, entry); 754 lwkt_reltoken(&vmspace_token); 755 } 756 757 static __inline void 758 vm_map_entry_unlink(vm_map_t map, 759 vm_map_entry_t entry) 760 { 761 vm_map_entry_t prev; 762 vm_map_entry_t next; 763 764 ASSERT_VM_MAP_LOCKED(map); 765 766 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 767 panic("vm_map_entry_unlink: attempt to mess with " 768 "locked entry! %p", entry); 769 } 770 lwkt_gettoken(&vmspace_token); 771 prev = entry->prev; 772 next = entry->next; 773 next->prev = prev; 774 prev->next = next; 775 vm_map_rb_tree_RB_REMOVE(&map->rb_root, entry); 776 map->nentries--; 777 lwkt_reltoken(&vmspace_token); 778 } 779 780 /* 781 * Finds the map entry containing (or immediately preceding) the specified 782 * address in the given map. The entry is returned in (*entry). 783 * 784 * The boolean result indicates whether the address is actually contained 785 * in the map. 786 * 787 * The related map must be locked. 788 * No other requirements. 789 */ 790 boolean_t 791 vm_map_lookup_entry(vm_map_t map, vm_offset_t address, vm_map_entry_t *entry) 792 { 793 vm_map_entry_t tmp; 794 vm_map_entry_t last; 795 796 ASSERT_VM_MAP_LOCKED(map); 797 #if 0 798 /* 799 * XXX TEMPORARILY DISABLED. For some reason our attempt to revive 800 * the hint code with the red-black lookup meets with system crashes 801 * and lockups. We do not yet know why. 802 * 803 * It is possible that the problem is related to the setting 804 * of the hint during map_entry deletion, in the code specified 805 * at the GGG comment later on in this file. 806 */ 807 /* 808 * Quickly check the cached hint, there's a good chance of a match. 809 */ 810 if (map->hint != &map->header) { 811 tmp = map->hint; 812 if (address >= tmp->start && address < tmp->end) { 813 *entry = tmp; 814 return(TRUE); 815 } 816 } 817 #endif 818 819 /* 820 * Locate the record from the top of the tree. 'last' tracks the 821 * closest prior record and is returned if no match is found, which 822 * in binary tree terms means tracking the most recent right-branch 823 * taken. If there is no prior record, &map->header is returned. 824 */ 825 last = &map->header; 826 tmp = RB_ROOT(&map->rb_root); 827 828 while (tmp) { 829 if (address >= tmp->start) { 830 if (address < tmp->end) { 831 *entry = tmp; 832 map->hint = tmp; 833 return(TRUE); 834 } 835 last = tmp; 836 tmp = RB_RIGHT(tmp, rb_entry); 837 } else { 838 tmp = RB_LEFT(tmp, rb_entry); 839 } 840 } 841 *entry = last; 842 return (FALSE); 843 } 844 845 /* 846 * Inserts the given whole VM object into the target map at the specified 847 * address range. The object's size should match that of the address range. 848 * 849 * The map must be exclusively locked. 850 * The caller must have reserved sufficient vm_map_entry structures. 851 * 852 * If object is non-NULL, ref count must be bumped by caller 853 * prior to making call to account for the new entry. 854 */ 855 int 856 vm_map_insert(vm_map_t map, int *countp, 857 vm_object_t object, vm_ooffset_t offset, 858 vm_offset_t start, vm_offset_t end, 859 vm_maptype_t maptype, 860 vm_prot_t prot, vm_prot_t max, 861 int cow) 862 { 863 vm_map_entry_t new_entry; 864 vm_map_entry_t prev_entry; 865 vm_map_entry_t temp_entry; 866 vm_eflags_t protoeflags; 867 868 ASSERT_VM_MAP_LOCKED(map); 869 870 /* 871 * Check that the start and end points are not bogus. 872 */ 873 if ((start < map->min_offset) || (end > map->max_offset) || 874 (start >= end)) 875 return (KERN_INVALID_ADDRESS); 876 877 /* 878 * Find the entry prior to the proposed starting address; if it's part 879 * of an existing entry, this range is bogus. 880 */ 881 if (vm_map_lookup_entry(map, start, &temp_entry)) 882 return (KERN_NO_SPACE); 883 884 prev_entry = temp_entry; 885 886 /* 887 * Assert that the next entry doesn't overlap the end point. 888 */ 889 890 if ((prev_entry->next != &map->header) && 891 (prev_entry->next->start < end)) 892 return (KERN_NO_SPACE); 893 894 protoeflags = 0; 895 896 if (cow & MAP_COPY_ON_WRITE) 897 protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY; 898 899 if (cow & MAP_NOFAULT) { 900 protoeflags |= MAP_ENTRY_NOFAULT; 901 902 KASSERT(object == NULL, 903 ("vm_map_insert: paradoxical MAP_NOFAULT request")); 904 } 905 if (cow & MAP_DISABLE_SYNCER) 906 protoeflags |= MAP_ENTRY_NOSYNC; 907 if (cow & MAP_DISABLE_COREDUMP) 908 protoeflags |= MAP_ENTRY_NOCOREDUMP; 909 if (cow & MAP_IS_STACK) 910 protoeflags |= MAP_ENTRY_STACK; 911 912 lwkt_gettoken(&vm_token); 913 lwkt_gettoken(&vmobj_token); 914 915 if (object) { 916 /* 917 * When object is non-NULL, it could be shared with another 918 * process. We have to set or clear OBJ_ONEMAPPING 919 * appropriately. 920 */ 921 if ((object->ref_count > 1) || (object->shadow_count != 0)) { 922 vm_object_clear_flag(object, OBJ_ONEMAPPING); 923 } 924 } 925 else if ((prev_entry != &map->header) && 926 (prev_entry->eflags == protoeflags) && 927 (prev_entry->end == start) && 928 (prev_entry->wired_count == 0) && 929 prev_entry->maptype == maptype && 930 ((prev_entry->object.vm_object == NULL) || 931 vm_object_coalesce(prev_entry->object.vm_object, 932 OFF_TO_IDX(prev_entry->offset), 933 (vm_size_t)(prev_entry->end - prev_entry->start), 934 (vm_size_t)(end - prev_entry->end)))) { 935 /* 936 * We were able to extend the object. Determine if we 937 * can extend the previous map entry to include the 938 * new range as well. 939 */ 940 if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) && 941 (prev_entry->protection == prot) && 942 (prev_entry->max_protection == max)) { 943 lwkt_reltoken(&vmobj_token); 944 lwkt_reltoken(&vm_token); 945 map->size += (end - prev_entry->end); 946 prev_entry->end = end; 947 vm_map_simplify_entry(map, prev_entry, countp); 948 return (KERN_SUCCESS); 949 } 950 951 /* 952 * If we can extend the object but cannot extend the 953 * map entry, we have to create a new map entry. We 954 * must bump the ref count on the extended object to 955 * account for it. object may be NULL. 956 */ 957 object = prev_entry->object.vm_object; 958 offset = prev_entry->offset + 959 (prev_entry->end - prev_entry->start); 960 vm_object_reference_locked(object); 961 } 962 963 lwkt_reltoken(&vmobj_token); 964 lwkt_reltoken(&vm_token); 965 966 /* 967 * NOTE: if conditionals fail, object can be NULL here. This occurs 968 * in things like the buffer map where we manage kva but do not manage 969 * backing objects. 970 */ 971 972 /* 973 * Create a new entry 974 */ 975 976 new_entry = vm_map_entry_create(map, countp); 977 new_entry->start = start; 978 new_entry->end = end; 979 980 new_entry->maptype = maptype; 981 new_entry->eflags = protoeflags; 982 new_entry->object.vm_object = object; 983 new_entry->offset = offset; 984 new_entry->aux.master_pde = 0; 985 986 new_entry->inheritance = VM_INHERIT_DEFAULT; 987 new_entry->protection = prot; 988 new_entry->max_protection = max; 989 new_entry->wired_count = 0; 990 991 /* 992 * Insert the new entry into the list 993 */ 994 995 vm_map_entry_link(map, prev_entry, new_entry); 996 map->size += new_entry->end - new_entry->start; 997 998 /* 999 * Update the free space hint. Entries cannot overlap. 1000 * An exact comparison is needed to avoid matching 1001 * against the map->header. 1002 */ 1003 if ((map->first_free == prev_entry) && 1004 (prev_entry->end == new_entry->start)) { 1005 map->first_free = new_entry; 1006 } 1007 1008 #if 0 1009 /* 1010 * Temporarily removed to avoid MAP_STACK panic, due to 1011 * MAP_STACK being a huge hack. Will be added back in 1012 * when MAP_STACK (and the user stack mapping) is fixed. 1013 */ 1014 /* 1015 * It may be possible to simplify the entry 1016 */ 1017 vm_map_simplify_entry(map, new_entry, countp); 1018 #endif 1019 1020 /* 1021 * Try to pre-populate the page table. Mappings governed by virtual 1022 * page tables cannot be prepopulated without a lot of work, so 1023 * don't try. 1024 */ 1025 if ((cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) && 1026 maptype != VM_MAPTYPE_VPAGETABLE) { 1027 pmap_object_init_pt(map->pmap, start, prot, 1028 object, OFF_TO_IDX(offset), end - start, 1029 cow & MAP_PREFAULT_PARTIAL); 1030 } 1031 1032 return (KERN_SUCCESS); 1033 } 1034 1035 /* 1036 * Find sufficient space for `length' bytes in the given map, starting at 1037 * `start'. Returns 0 on success, 1 on no space. 1038 * 1039 * This function will returned an arbitrarily aligned pointer. If no 1040 * particular alignment is required you should pass align as 1. Note that 1041 * the map may return PAGE_SIZE aligned pointers if all the lengths used in 1042 * the map are a multiple of PAGE_SIZE, even if you pass a smaller align 1043 * argument. 1044 * 1045 * 'align' should be a power of 2 but is not required to be. 1046 * 1047 * The map must be exclusively locked. 1048 * No other requirements. 1049 */ 1050 int 1051 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, 1052 vm_size_t align, int flags, vm_offset_t *addr) 1053 { 1054 vm_map_entry_t entry, next; 1055 vm_offset_t end; 1056 vm_offset_t align_mask; 1057 1058 if (start < map->min_offset) 1059 start = map->min_offset; 1060 if (start > map->max_offset) 1061 return (1); 1062 1063 /* 1064 * If the alignment is not a power of 2 we will have to use 1065 * a mod/division, set align_mask to a special value. 1066 */ 1067 if ((align | (align - 1)) + 1 != (align << 1)) 1068 align_mask = (vm_offset_t)-1; 1069 else 1070 align_mask = align - 1; 1071 1072 retry: 1073 /* 1074 * Look for the first possible address; if there's already something 1075 * at this address, we have to start after it. 1076 */ 1077 if (start == map->min_offset) { 1078 if ((entry = map->first_free) != &map->header) 1079 start = entry->end; 1080 } else { 1081 vm_map_entry_t tmp; 1082 1083 if (vm_map_lookup_entry(map, start, &tmp)) 1084 start = tmp->end; 1085 entry = tmp; 1086 } 1087 1088 /* 1089 * Look through the rest of the map, trying to fit a new region in the 1090 * gap between existing regions, or after the very last region. 1091 */ 1092 for (;; start = (entry = next)->end) { 1093 /* 1094 * Adjust the proposed start by the requested alignment, 1095 * be sure that we didn't wrap the address. 1096 */ 1097 if (align_mask == (vm_offset_t)-1) 1098 end = ((start + align - 1) / align) * align; 1099 else 1100 end = (start + align_mask) & ~align_mask; 1101 if (end < start) 1102 return (1); 1103 start = end; 1104 /* 1105 * Find the end of the proposed new region. Be sure we didn't 1106 * go beyond the end of the map, or wrap around the address. 1107 * Then check to see if this is the last entry or if the 1108 * proposed end fits in the gap between this and the next 1109 * entry. 1110 */ 1111 end = start + length; 1112 if (end > map->max_offset || end < start) 1113 return (1); 1114 next = entry->next; 1115 1116 /* 1117 * If the next entry's start address is beyond the desired 1118 * end address we may have found a good entry. 1119 * 1120 * If the next entry is a stack mapping we do not map into 1121 * the stack's reserved space. 1122 * 1123 * XXX continue to allow mapping into the stack's reserved 1124 * space if doing a MAP_STACK mapping inside a MAP_STACK 1125 * mapping, for backwards compatibility. But the caller 1126 * really should use MAP_STACK | MAP_TRYFIXED if they 1127 * want to do that. 1128 */ 1129 if (next == &map->header) 1130 break; 1131 if (next->start >= end) { 1132 if ((next->eflags & MAP_ENTRY_STACK) == 0) 1133 break; 1134 if (flags & MAP_STACK) 1135 break; 1136 if (next->start - next->aux.avail_ssize >= end) 1137 break; 1138 } 1139 } 1140 map->hint = entry; 1141 if (map == &kernel_map) { 1142 vm_offset_t ksize; 1143 if ((ksize = round_page(start + length)) > kernel_vm_end) { 1144 pmap_growkernel(ksize); 1145 goto retry; 1146 } 1147 } 1148 *addr = start; 1149 return (0); 1150 } 1151 1152 /* 1153 * vm_map_find finds an unallocated region in the target address map with 1154 * the given length. The search is defined to be first-fit from the 1155 * specified address; the region found is returned in the same parameter. 1156 * 1157 * If object is non-NULL, ref count must be bumped by caller 1158 * prior to making call to account for the new entry. 1159 * 1160 * No requirements. This function will lock the map temporarily. 1161 */ 1162 int 1163 vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1164 vm_offset_t *addr, vm_size_t length, vm_size_t align, 1165 boolean_t fitit, 1166 vm_maptype_t maptype, 1167 vm_prot_t prot, vm_prot_t max, 1168 int cow) 1169 { 1170 vm_offset_t start; 1171 int result; 1172 int count; 1173 1174 start = *addr; 1175 1176 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1177 vm_map_lock(map); 1178 if (fitit) { 1179 if (vm_map_findspace(map, start, length, align, 0, addr)) { 1180 vm_map_unlock(map); 1181 vm_map_entry_release(count); 1182 return (KERN_NO_SPACE); 1183 } 1184 start = *addr; 1185 } 1186 result = vm_map_insert(map, &count, object, offset, 1187 start, start + length, 1188 maptype, 1189 prot, max, 1190 cow); 1191 vm_map_unlock(map); 1192 vm_map_entry_release(count); 1193 1194 return (result); 1195 } 1196 1197 /* 1198 * Simplify the given map entry by merging with either neighbor. This 1199 * routine also has the ability to merge with both neighbors. 1200 * 1201 * This routine guarentees that the passed entry remains valid (though 1202 * possibly extended). When merging, this routine may delete one or 1203 * both neighbors. No action is taken on entries which have their 1204 * in-transition flag set. 1205 * 1206 * The map must be exclusively locked. 1207 */ 1208 void 1209 vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry, int *countp) 1210 { 1211 vm_map_entry_t next, prev; 1212 vm_size_t prevsize, esize; 1213 1214 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1215 ++mycpu->gd_cnt.v_intrans_coll; 1216 return; 1217 } 1218 1219 if (entry->maptype == VM_MAPTYPE_SUBMAP) 1220 return; 1221 1222 prev = entry->prev; 1223 if (prev != &map->header) { 1224 prevsize = prev->end - prev->start; 1225 if ( (prev->end == entry->start) && 1226 (prev->maptype == entry->maptype) && 1227 (prev->object.vm_object == entry->object.vm_object) && 1228 (!prev->object.vm_object || 1229 (prev->offset + prevsize == entry->offset)) && 1230 (prev->eflags == entry->eflags) && 1231 (prev->protection == entry->protection) && 1232 (prev->max_protection == entry->max_protection) && 1233 (prev->inheritance == entry->inheritance) && 1234 (prev->wired_count == entry->wired_count)) { 1235 if (map->first_free == prev) 1236 map->first_free = entry; 1237 if (map->hint == prev) 1238 map->hint = entry; 1239 vm_map_entry_unlink(map, prev); 1240 entry->start = prev->start; 1241 entry->offset = prev->offset; 1242 if (prev->object.vm_object) 1243 vm_object_deallocate(prev->object.vm_object); 1244 vm_map_entry_dispose(map, prev, countp); 1245 } 1246 } 1247 1248 next = entry->next; 1249 if (next != &map->header) { 1250 esize = entry->end - entry->start; 1251 if ((entry->end == next->start) && 1252 (next->maptype == entry->maptype) && 1253 (next->object.vm_object == entry->object.vm_object) && 1254 (!entry->object.vm_object || 1255 (entry->offset + esize == next->offset)) && 1256 (next->eflags == entry->eflags) && 1257 (next->protection == entry->protection) && 1258 (next->max_protection == entry->max_protection) && 1259 (next->inheritance == entry->inheritance) && 1260 (next->wired_count == entry->wired_count)) { 1261 if (map->first_free == next) 1262 map->first_free = entry; 1263 if (map->hint == next) 1264 map->hint = entry; 1265 vm_map_entry_unlink(map, next); 1266 entry->end = next->end; 1267 if (next->object.vm_object) 1268 vm_object_deallocate(next->object.vm_object); 1269 vm_map_entry_dispose(map, next, countp); 1270 } 1271 } 1272 } 1273 1274 /* 1275 * Asserts that the given entry begins at or after the specified address. 1276 * If necessary, it splits the entry into two. 1277 */ 1278 #define vm_map_clip_start(map, entry, startaddr, countp) \ 1279 { \ 1280 if (startaddr > entry->start) \ 1281 _vm_map_clip_start(map, entry, startaddr, countp); \ 1282 } 1283 1284 /* 1285 * This routine is called only when it is known that the entry must be split. 1286 * 1287 * The map must be exclusively locked. 1288 */ 1289 static void 1290 _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start, 1291 int *countp) 1292 { 1293 vm_map_entry_t new_entry; 1294 1295 /* 1296 * Split off the front portion -- note that we must insert the new 1297 * entry BEFORE this one, so that this entry has the specified 1298 * starting address. 1299 */ 1300 1301 vm_map_simplify_entry(map, entry, countp); 1302 1303 /* 1304 * If there is no object backing this entry, we might as well create 1305 * one now. If we defer it, an object can get created after the map 1306 * is clipped, and individual objects will be created for the split-up 1307 * map. This is a bit of a hack, but is also about the best place to 1308 * put this improvement. 1309 */ 1310 if (entry->object.vm_object == NULL && !map->system_map) { 1311 vm_map_entry_allocate_object(entry); 1312 } 1313 1314 new_entry = vm_map_entry_create(map, countp); 1315 *new_entry = *entry; 1316 1317 new_entry->end = start; 1318 entry->offset += (start - entry->start); 1319 entry->start = start; 1320 1321 vm_map_entry_link(map, entry->prev, new_entry); 1322 1323 switch(entry->maptype) { 1324 case VM_MAPTYPE_NORMAL: 1325 case VM_MAPTYPE_VPAGETABLE: 1326 vm_object_reference(new_entry->object.vm_object); 1327 break; 1328 default: 1329 break; 1330 } 1331 } 1332 1333 /* 1334 * Asserts that the given entry ends at or before the specified address. 1335 * If necessary, it splits the entry into two. 1336 * 1337 * The map must be exclusively locked. 1338 */ 1339 #define vm_map_clip_end(map, entry, endaddr, countp) \ 1340 { \ 1341 if (endaddr < entry->end) \ 1342 _vm_map_clip_end(map, entry, endaddr, countp); \ 1343 } 1344 1345 /* 1346 * This routine is called only when it is known that the entry must be split. 1347 * 1348 * The map must be exclusively locked. 1349 */ 1350 static void 1351 _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end, 1352 int *countp) 1353 { 1354 vm_map_entry_t new_entry; 1355 1356 /* 1357 * If there is no object backing this entry, we might as well create 1358 * one now. If we defer it, an object can get created after the map 1359 * is clipped, and individual objects will be created for the split-up 1360 * map. This is a bit of a hack, but is also about the best place to 1361 * put this improvement. 1362 */ 1363 1364 if (entry->object.vm_object == NULL && !map->system_map) { 1365 vm_map_entry_allocate_object(entry); 1366 } 1367 1368 /* 1369 * Create a new entry and insert it AFTER the specified entry 1370 */ 1371 1372 new_entry = vm_map_entry_create(map, countp); 1373 *new_entry = *entry; 1374 1375 new_entry->start = entry->end = end; 1376 new_entry->offset += (end - entry->start); 1377 1378 vm_map_entry_link(map, entry, new_entry); 1379 1380 switch(entry->maptype) { 1381 case VM_MAPTYPE_NORMAL: 1382 case VM_MAPTYPE_VPAGETABLE: 1383 vm_object_reference(new_entry->object.vm_object); 1384 break; 1385 default: 1386 break; 1387 } 1388 } 1389 1390 /* 1391 * Asserts that the starting and ending region addresses fall within the 1392 * valid range for the map. 1393 */ 1394 #define VM_MAP_RANGE_CHECK(map, start, end) \ 1395 { \ 1396 if (start < vm_map_min(map)) \ 1397 start = vm_map_min(map); \ 1398 if (end > vm_map_max(map)) \ 1399 end = vm_map_max(map); \ 1400 if (start > end) \ 1401 start = end; \ 1402 } 1403 1404 /* 1405 * Used to block when an in-transition collison occurs. The map 1406 * is unlocked for the sleep and relocked before the return. 1407 */ 1408 static 1409 void 1410 vm_map_transition_wait(vm_map_t map) 1411 { 1412 vm_map_unlock(map); 1413 tsleep(map, 0, "vment", 0); 1414 vm_map_lock(map); 1415 } 1416 1417 /* 1418 * When we do blocking operations with the map lock held it is 1419 * possible that a clip might have occured on our in-transit entry, 1420 * requiring an adjustment to the entry in our loop. These macros 1421 * help the pageable and clip_range code deal with the case. The 1422 * conditional costs virtually nothing if no clipping has occured. 1423 */ 1424 1425 #define CLIP_CHECK_BACK(entry, save_start) \ 1426 do { \ 1427 while (entry->start != save_start) { \ 1428 entry = entry->prev; \ 1429 KASSERT(entry != &map->header, ("bad entry clip")); \ 1430 } \ 1431 } while(0) 1432 1433 #define CLIP_CHECK_FWD(entry, save_end) \ 1434 do { \ 1435 while (entry->end != save_end) { \ 1436 entry = entry->next; \ 1437 KASSERT(entry != &map->header, ("bad entry clip")); \ 1438 } \ 1439 } while(0) 1440 1441 1442 /* 1443 * Clip the specified range and return the base entry. The 1444 * range may cover several entries starting at the returned base 1445 * and the first and last entry in the covering sequence will be 1446 * properly clipped to the requested start and end address. 1447 * 1448 * If no holes are allowed you should pass the MAP_CLIP_NO_HOLES 1449 * flag. 1450 * 1451 * The MAP_ENTRY_IN_TRANSITION flag will be set for the entries 1452 * covered by the requested range. 1453 * 1454 * The map must be exclusively locked on entry and will remain locked 1455 * on return. If no range exists or the range contains holes and you 1456 * specified that no holes were allowed, NULL will be returned. This 1457 * routine may temporarily unlock the map in order avoid a deadlock when 1458 * sleeping. 1459 */ 1460 static 1461 vm_map_entry_t 1462 vm_map_clip_range(vm_map_t map, vm_offset_t start, vm_offset_t end, 1463 int *countp, int flags) 1464 { 1465 vm_map_entry_t start_entry; 1466 vm_map_entry_t entry; 1467 1468 /* 1469 * Locate the entry and effect initial clipping. The in-transition 1470 * case does not occur very often so do not try to optimize it. 1471 */ 1472 again: 1473 if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) 1474 return (NULL); 1475 entry = start_entry; 1476 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1477 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1478 ++mycpu->gd_cnt.v_intrans_coll; 1479 ++mycpu->gd_cnt.v_intrans_wait; 1480 vm_map_transition_wait(map); 1481 /* 1482 * entry and/or start_entry may have been clipped while 1483 * we slept, or may have gone away entirely. We have 1484 * to restart from the lookup. 1485 */ 1486 goto again; 1487 } 1488 1489 /* 1490 * Since we hold an exclusive map lock we do not have to restart 1491 * after clipping, even though clipping may block in zalloc. 1492 */ 1493 vm_map_clip_start(map, entry, start, countp); 1494 vm_map_clip_end(map, entry, end, countp); 1495 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 1496 1497 /* 1498 * Scan entries covered by the range. When working on the next 1499 * entry a restart need only re-loop on the current entry which 1500 * we have already locked, since 'next' may have changed. Also, 1501 * even though entry is safe, it may have been clipped so we 1502 * have to iterate forwards through the clip after sleeping. 1503 */ 1504 while (entry->next != &map->header && entry->next->start < end) { 1505 vm_map_entry_t next = entry->next; 1506 1507 if (flags & MAP_CLIP_NO_HOLES) { 1508 if (next->start > entry->end) { 1509 vm_map_unclip_range(map, start_entry, 1510 start, entry->end, countp, flags); 1511 return(NULL); 1512 } 1513 } 1514 1515 if (next->eflags & MAP_ENTRY_IN_TRANSITION) { 1516 vm_offset_t save_end = entry->end; 1517 next->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1518 ++mycpu->gd_cnt.v_intrans_coll; 1519 ++mycpu->gd_cnt.v_intrans_wait; 1520 vm_map_transition_wait(map); 1521 1522 /* 1523 * clips might have occured while we blocked. 1524 */ 1525 CLIP_CHECK_FWD(entry, save_end); 1526 CLIP_CHECK_BACK(start_entry, start); 1527 continue; 1528 } 1529 /* 1530 * No restart necessary even though clip_end may block, we 1531 * are holding the map lock. 1532 */ 1533 vm_map_clip_end(map, next, end, countp); 1534 next->eflags |= MAP_ENTRY_IN_TRANSITION; 1535 entry = next; 1536 } 1537 if (flags & MAP_CLIP_NO_HOLES) { 1538 if (entry->end != end) { 1539 vm_map_unclip_range(map, start_entry, 1540 start, entry->end, countp, flags); 1541 return(NULL); 1542 } 1543 } 1544 return(start_entry); 1545 } 1546 1547 /* 1548 * Undo the effect of vm_map_clip_range(). You should pass the same 1549 * flags and the same range that you passed to vm_map_clip_range(). 1550 * This code will clear the in-transition flag on the entries and 1551 * wake up anyone waiting. This code will also simplify the sequence 1552 * and attempt to merge it with entries before and after the sequence. 1553 * 1554 * The map must be locked on entry and will remain locked on return. 1555 * 1556 * Note that you should also pass the start_entry returned by 1557 * vm_map_clip_range(). However, if you block between the two calls 1558 * with the map unlocked please be aware that the start_entry may 1559 * have been clipped and you may need to scan it backwards to find 1560 * the entry corresponding with the original start address. You are 1561 * responsible for this, vm_map_unclip_range() expects the correct 1562 * start_entry to be passed to it and will KASSERT otherwise. 1563 */ 1564 static 1565 void 1566 vm_map_unclip_range(vm_map_t map, vm_map_entry_t start_entry, 1567 vm_offset_t start, vm_offset_t end, 1568 int *countp, int flags) 1569 { 1570 vm_map_entry_t entry; 1571 1572 entry = start_entry; 1573 1574 KASSERT(entry->start == start, ("unclip_range: illegal base entry")); 1575 while (entry != &map->header && entry->start < end) { 1576 KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION, 1577 ("in-transition flag not set during unclip on: %p", 1578 entry)); 1579 KASSERT(entry->end <= end, 1580 ("unclip_range: tail wasn't clipped")); 1581 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; 1582 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 1583 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 1584 wakeup(map); 1585 } 1586 entry = entry->next; 1587 } 1588 1589 /* 1590 * Simplification does not block so there is no restart case. 1591 */ 1592 entry = start_entry; 1593 while (entry != &map->header && entry->start < end) { 1594 vm_map_simplify_entry(map, entry, countp); 1595 entry = entry->next; 1596 } 1597 } 1598 1599 /* 1600 * Mark the given range as handled by a subordinate map. 1601 * 1602 * This range must have been created with vm_map_find(), and no other 1603 * operations may have been performed on this range prior to calling 1604 * vm_map_submap(). 1605 * 1606 * Submappings cannot be removed. 1607 * 1608 * No requirements. 1609 */ 1610 int 1611 vm_map_submap(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_map_t submap) 1612 { 1613 vm_map_entry_t entry; 1614 int result = KERN_INVALID_ARGUMENT; 1615 int count; 1616 1617 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1618 vm_map_lock(map); 1619 1620 VM_MAP_RANGE_CHECK(map, start, end); 1621 1622 if (vm_map_lookup_entry(map, start, &entry)) { 1623 vm_map_clip_start(map, entry, start, &count); 1624 } else { 1625 entry = entry->next; 1626 } 1627 1628 vm_map_clip_end(map, entry, end, &count); 1629 1630 if ((entry->start == start) && (entry->end == end) && 1631 ((entry->eflags & MAP_ENTRY_COW) == 0) && 1632 (entry->object.vm_object == NULL)) { 1633 entry->object.sub_map = submap; 1634 entry->maptype = VM_MAPTYPE_SUBMAP; 1635 result = KERN_SUCCESS; 1636 } 1637 vm_map_unlock(map); 1638 vm_map_entry_release(count); 1639 1640 return (result); 1641 } 1642 1643 /* 1644 * Sets the protection of the specified address region in the target map. 1645 * If "set_max" is specified, the maximum protection is to be set; 1646 * otherwise, only the current protection is affected. 1647 * 1648 * The protection is not applicable to submaps, but is applicable to normal 1649 * maps and maps governed by virtual page tables. For example, when operating 1650 * on a virtual page table our protection basically controls how COW occurs 1651 * on the backing object, whereas the virtual page table abstraction itself 1652 * is an abstraction for userland. 1653 * 1654 * No requirements. 1655 */ 1656 int 1657 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, 1658 vm_prot_t new_prot, boolean_t set_max) 1659 { 1660 vm_map_entry_t current; 1661 vm_map_entry_t entry; 1662 int count; 1663 1664 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1665 vm_map_lock(map); 1666 1667 VM_MAP_RANGE_CHECK(map, start, end); 1668 1669 if (vm_map_lookup_entry(map, start, &entry)) { 1670 vm_map_clip_start(map, entry, start, &count); 1671 } else { 1672 entry = entry->next; 1673 } 1674 1675 /* 1676 * Make a first pass to check for protection violations. 1677 */ 1678 current = entry; 1679 while ((current != &map->header) && (current->start < end)) { 1680 if (current->maptype == VM_MAPTYPE_SUBMAP) { 1681 vm_map_unlock(map); 1682 vm_map_entry_release(count); 1683 return (KERN_INVALID_ARGUMENT); 1684 } 1685 if ((new_prot & current->max_protection) != new_prot) { 1686 vm_map_unlock(map); 1687 vm_map_entry_release(count); 1688 return (KERN_PROTECTION_FAILURE); 1689 } 1690 current = current->next; 1691 } 1692 1693 /* 1694 * Go back and fix up protections. [Note that clipping is not 1695 * necessary the second time.] 1696 */ 1697 current = entry; 1698 1699 while ((current != &map->header) && (current->start < end)) { 1700 vm_prot_t old_prot; 1701 1702 vm_map_clip_end(map, current, end, &count); 1703 1704 old_prot = current->protection; 1705 if (set_max) { 1706 current->protection = 1707 (current->max_protection = new_prot) & 1708 old_prot; 1709 } else { 1710 current->protection = new_prot; 1711 } 1712 1713 /* 1714 * Update physical map if necessary. Worry about copy-on-write 1715 * here -- CHECK THIS XXX 1716 */ 1717 1718 if (current->protection != old_prot) { 1719 #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ 1720 VM_PROT_ALL) 1721 1722 pmap_protect(map->pmap, current->start, 1723 current->end, 1724 current->protection & MASK(current)); 1725 #undef MASK 1726 } 1727 1728 vm_map_simplify_entry(map, current, &count); 1729 1730 current = current->next; 1731 } 1732 1733 vm_map_unlock(map); 1734 vm_map_entry_release(count); 1735 return (KERN_SUCCESS); 1736 } 1737 1738 /* 1739 * This routine traverses a processes map handling the madvise 1740 * system call. Advisories are classified as either those effecting 1741 * the vm_map_entry structure, or those effecting the underlying 1742 * objects. 1743 * 1744 * The <value> argument is used for extended madvise calls. 1745 * 1746 * No requirements. 1747 */ 1748 int 1749 vm_map_madvise(vm_map_t map, vm_offset_t start, vm_offset_t end, 1750 int behav, off_t value) 1751 { 1752 vm_map_entry_t current, entry; 1753 int modify_map = 0; 1754 int error = 0; 1755 int count; 1756 1757 /* 1758 * Some madvise calls directly modify the vm_map_entry, in which case 1759 * we need to use an exclusive lock on the map and we need to perform 1760 * various clipping operations. Otherwise we only need a read-lock 1761 * on the map. 1762 */ 1763 1764 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1765 1766 switch(behav) { 1767 case MADV_NORMAL: 1768 case MADV_SEQUENTIAL: 1769 case MADV_RANDOM: 1770 case MADV_NOSYNC: 1771 case MADV_AUTOSYNC: 1772 case MADV_NOCORE: 1773 case MADV_CORE: 1774 case MADV_SETMAP: 1775 case MADV_INVAL: 1776 modify_map = 1; 1777 vm_map_lock(map); 1778 break; 1779 case MADV_WILLNEED: 1780 case MADV_DONTNEED: 1781 case MADV_FREE: 1782 vm_map_lock_read(map); 1783 break; 1784 default: 1785 vm_map_entry_release(count); 1786 return (EINVAL); 1787 } 1788 1789 /* 1790 * Locate starting entry and clip if necessary. 1791 */ 1792 1793 VM_MAP_RANGE_CHECK(map, start, end); 1794 1795 if (vm_map_lookup_entry(map, start, &entry)) { 1796 if (modify_map) 1797 vm_map_clip_start(map, entry, start, &count); 1798 } else { 1799 entry = entry->next; 1800 } 1801 1802 if (modify_map) { 1803 /* 1804 * madvise behaviors that are implemented in the vm_map_entry. 1805 * 1806 * We clip the vm_map_entry so that behavioral changes are 1807 * limited to the specified address range. 1808 */ 1809 for (current = entry; 1810 (current != &map->header) && (current->start < end); 1811 current = current->next 1812 ) { 1813 if (current->maptype == VM_MAPTYPE_SUBMAP) 1814 continue; 1815 1816 vm_map_clip_end(map, current, end, &count); 1817 1818 switch (behav) { 1819 case MADV_NORMAL: 1820 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); 1821 break; 1822 case MADV_SEQUENTIAL: 1823 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); 1824 break; 1825 case MADV_RANDOM: 1826 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); 1827 break; 1828 case MADV_NOSYNC: 1829 current->eflags |= MAP_ENTRY_NOSYNC; 1830 break; 1831 case MADV_AUTOSYNC: 1832 current->eflags &= ~MAP_ENTRY_NOSYNC; 1833 break; 1834 case MADV_NOCORE: 1835 current->eflags |= MAP_ENTRY_NOCOREDUMP; 1836 break; 1837 case MADV_CORE: 1838 current->eflags &= ~MAP_ENTRY_NOCOREDUMP; 1839 break; 1840 case MADV_INVAL: 1841 /* 1842 * Invalidate the related pmap entries, used 1843 * to flush portions of the real kernel's 1844 * pmap when the caller has removed or 1845 * modified existing mappings in a virtual 1846 * page table. 1847 */ 1848 pmap_remove(map->pmap, 1849 current->start, current->end); 1850 break; 1851 case MADV_SETMAP: 1852 /* 1853 * Set the page directory page for a map 1854 * governed by a virtual page table. Mark 1855 * the entry as being governed by a virtual 1856 * page table if it is not. 1857 * 1858 * XXX the page directory page is stored 1859 * in the avail_ssize field if the map_entry. 1860 * 1861 * XXX the map simplification code does not 1862 * compare this field so weird things may 1863 * happen if you do not apply this function 1864 * to the entire mapping governed by the 1865 * virtual page table. 1866 */ 1867 if (current->maptype != VM_MAPTYPE_VPAGETABLE) { 1868 error = EINVAL; 1869 break; 1870 } 1871 current->aux.master_pde = value; 1872 pmap_remove(map->pmap, 1873 current->start, current->end); 1874 break; 1875 default: 1876 error = EINVAL; 1877 break; 1878 } 1879 vm_map_simplify_entry(map, current, &count); 1880 } 1881 vm_map_unlock(map); 1882 } else { 1883 vm_pindex_t pindex; 1884 int count; 1885 1886 /* 1887 * madvise behaviors that are implemented in the underlying 1888 * vm_object. 1889 * 1890 * Since we don't clip the vm_map_entry, we have to clip 1891 * the vm_object pindex and count. 1892 * 1893 * NOTE! We currently do not support these functions on 1894 * virtual page tables. 1895 */ 1896 for (current = entry; 1897 (current != &map->header) && (current->start < end); 1898 current = current->next 1899 ) { 1900 vm_offset_t useStart; 1901 1902 if (current->maptype != VM_MAPTYPE_NORMAL) 1903 continue; 1904 1905 pindex = OFF_TO_IDX(current->offset); 1906 count = atop(current->end - current->start); 1907 useStart = current->start; 1908 1909 if (current->start < start) { 1910 pindex += atop(start - current->start); 1911 count -= atop(start - current->start); 1912 useStart = start; 1913 } 1914 if (current->end > end) 1915 count -= atop(current->end - end); 1916 1917 if (count <= 0) 1918 continue; 1919 1920 vm_object_madvise(current->object.vm_object, 1921 pindex, count, behav); 1922 1923 /* 1924 * Try to populate the page table. Mappings governed 1925 * by virtual page tables cannot be pre-populated 1926 * without a lot of work so don't try. 1927 */ 1928 if (behav == MADV_WILLNEED && 1929 current->maptype != VM_MAPTYPE_VPAGETABLE) { 1930 pmap_object_init_pt( 1931 map->pmap, 1932 useStart, 1933 current->protection, 1934 current->object.vm_object, 1935 pindex, 1936 (count << PAGE_SHIFT), 1937 MAP_PREFAULT_MADVISE 1938 ); 1939 } 1940 } 1941 vm_map_unlock_read(map); 1942 } 1943 vm_map_entry_release(count); 1944 return(error); 1945 } 1946 1947 1948 /* 1949 * Sets the inheritance of the specified address range in the target map. 1950 * Inheritance affects how the map will be shared with child maps at the 1951 * time of vm_map_fork. 1952 */ 1953 int 1954 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, 1955 vm_inherit_t new_inheritance) 1956 { 1957 vm_map_entry_t entry; 1958 vm_map_entry_t temp_entry; 1959 int count; 1960 1961 switch (new_inheritance) { 1962 case VM_INHERIT_NONE: 1963 case VM_INHERIT_COPY: 1964 case VM_INHERIT_SHARE: 1965 break; 1966 default: 1967 return (KERN_INVALID_ARGUMENT); 1968 } 1969 1970 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1971 vm_map_lock(map); 1972 1973 VM_MAP_RANGE_CHECK(map, start, end); 1974 1975 if (vm_map_lookup_entry(map, start, &temp_entry)) { 1976 entry = temp_entry; 1977 vm_map_clip_start(map, entry, start, &count); 1978 } else 1979 entry = temp_entry->next; 1980 1981 while ((entry != &map->header) && (entry->start < end)) { 1982 vm_map_clip_end(map, entry, end, &count); 1983 1984 entry->inheritance = new_inheritance; 1985 1986 vm_map_simplify_entry(map, entry, &count); 1987 1988 entry = entry->next; 1989 } 1990 vm_map_unlock(map); 1991 vm_map_entry_release(count); 1992 return (KERN_SUCCESS); 1993 } 1994 1995 /* 1996 * Implement the semantics of mlock 1997 */ 1998 int 1999 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, 2000 boolean_t new_pageable) 2001 { 2002 vm_map_entry_t entry; 2003 vm_map_entry_t start_entry; 2004 vm_offset_t end; 2005 int rv = KERN_SUCCESS; 2006 int count; 2007 2008 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2009 vm_map_lock(map); 2010 VM_MAP_RANGE_CHECK(map, start, real_end); 2011 end = real_end; 2012 2013 start_entry = vm_map_clip_range(map, start, end, &count, 2014 MAP_CLIP_NO_HOLES); 2015 if (start_entry == NULL) { 2016 vm_map_unlock(map); 2017 vm_map_entry_release(count); 2018 return (KERN_INVALID_ADDRESS); 2019 } 2020 2021 if (new_pageable == 0) { 2022 entry = start_entry; 2023 while ((entry != &map->header) && (entry->start < end)) { 2024 vm_offset_t save_start; 2025 vm_offset_t save_end; 2026 2027 /* 2028 * Already user wired or hard wired (trivial cases) 2029 */ 2030 if (entry->eflags & MAP_ENTRY_USER_WIRED) { 2031 entry = entry->next; 2032 continue; 2033 } 2034 if (entry->wired_count != 0) { 2035 entry->wired_count++; 2036 entry->eflags |= MAP_ENTRY_USER_WIRED; 2037 entry = entry->next; 2038 continue; 2039 } 2040 2041 /* 2042 * A new wiring requires instantiation of appropriate 2043 * management structures and the faulting in of the 2044 * page. 2045 */ 2046 if (entry->maptype != VM_MAPTYPE_SUBMAP) { 2047 int copyflag = entry->eflags & 2048 MAP_ENTRY_NEEDS_COPY; 2049 if (copyflag && ((entry->protection & 2050 VM_PROT_WRITE) != 0)) { 2051 vm_map_entry_shadow(entry); 2052 } else if (entry->object.vm_object == NULL && 2053 !map->system_map) { 2054 vm_map_entry_allocate_object(entry); 2055 } 2056 } 2057 entry->wired_count++; 2058 entry->eflags |= MAP_ENTRY_USER_WIRED; 2059 2060 /* 2061 * Now fault in the area. Note that vm_fault_wire() 2062 * may release the map lock temporarily, it will be 2063 * relocked on return. The in-transition 2064 * flag protects the entries. 2065 */ 2066 save_start = entry->start; 2067 save_end = entry->end; 2068 rv = vm_fault_wire(map, entry, TRUE); 2069 if (rv) { 2070 CLIP_CHECK_BACK(entry, save_start); 2071 for (;;) { 2072 KASSERT(entry->wired_count == 1, ("bad wired_count on entry")); 2073 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2074 entry->wired_count = 0; 2075 if (entry->end == save_end) 2076 break; 2077 entry = entry->next; 2078 KASSERT(entry != &map->header, ("bad entry clip during backout")); 2079 } 2080 end = save_start; /* unwire the rest */ 2081 break; 2082 } 2083 /* 2084 * note that even though the entry might have been 2085 * clipped, the USER_WIRED flag we set prevents 2086 * duplication so we do not have to do a 2087 * clip check. 2088 */ 2089 entry = entry->next; 2090 } 2091 2092 /* 2093 * If we failed fall through to the unwiring section to 2094 * unwire what we had wired so far. 'end' has already 2095 * been adjusted. 2096 */ 2097 if (rv) 2098 new_pageable = 1; 2099 2100 /* 2101 * start_entry might have been clipped if we unlocked the 2102 * map and blocked. No matter how clipped it has gotten 2103 * there should be a fragment that is on our start boundary. 2104 */ 2105 CLIP_CHECK_BACK(start_entry, start); 2106 } 2107 2108 /* 2109 * Deal with the unwiring case. 2110 */ 2111 if (new_pageable) { 2112 /* 2113 * This is the unwiring case. We must first ensure that the 2114 * range to be unwired is really wired down. We know there 2115 * are no holes. 2116 */ 2117 entry = start_entry; 2118 while ((entry != &map->header) && (entry->start < end)) { 2119 if ((entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 2120 rv = KERN_INVALID_ARGUMENT; 2121 goto done; 2122 } 2123 KASSERT(entry->wired_count != 0, ("wired count was 0 with USER_WIRED set! %p", entry)); 2124 entry = entry->next; 2125 } 2126 2127 /* 2128 * Now decrement the wiring count for each region. If a region 2129 * becomes completely unwired, unwire its physical pages and 2130 * mappings. 2131 */ 2132 /* 2133 * The map entries are processed in a loop, checking to 2134 * make sure the entry is wired and asserting it has a wired 2135 * count. However, another loop was inserted more-or-less in 2136 * the middle of the unwiring path. This loop picks up the 2137 * "entry" loop variable from the first loop without first 2138 * setting it to start_entry. Naturally, the secound loop 2139 * is never entered and the pages backing the entries are 2140 * never unwired. This can lead to a leak of wired pages. 2141 */ 2142 entry = start_entry; 2143 while ((entry != &map->header) && (entry->start < end)) { 2144 KASSERT(entry->eflags & MAP_ENTRY_USER_WIRED, 2145 ("expected USER_WIRED on entry %p", entry)); 2146 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2147 entry->wired_count--; 2148 if (entry->wired_count == 0) 2149 vm_fault_unwire(map, entry); 2150 entry = entry->next; 2151 } 2152 } 2153 done: 2154 vm_map_unclip_range(map, start_entry, start, real_end, &count, 2155 MAP_CLIP_NO_HOLES); 2156 map->timestamp++; 2157 vm_map_unlock(map); 2158 vm_map_entry_release(count); 2159 return (rv); 2160 } 2161 2162 /* 2163 * Sets the pageability of the specified address range in the target map. 2164 * Regions specified as not pageable require locked-down physical 2165 * memory and physical page maps. 2166 * 2167 * The map must not be locked, but a reference must remain to the map 2168 * throughout the call. 2169 * 2170 * This function may be called via the zalloc path and must properly 2171 * reserve map entries for kernel_map. 2172 * 2173 * No requirements. 2174 */ 2175 int 2176 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, int kmflags) 2177 { 2178 vm_map_entry_t entry; 2179 vm_map_entry_t start_entry; 2180 vm_offset_t end; 2181 int rv = KERN_SUCCESS; 2182 int count; 2183 2184 if (kmflags & KM_KRESERVE) 2185 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); 2186 else 2187 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2188 vm_map_lock(map); 2189 VM_MAP_RANGE_CHECK(map, start, real_end); 2190 end = real_end; 2191 2192 start_entry = vm_map_clip_range(map, start, end, &count, 2193 MAP_CLIP_NO_HOLES); 2194 if (start_entry == NULL) { 2195 vm_map_unlock(map); 2196 rv = KERN_INVALID_ADDRESS; 2197 goto failure; 2198 } 2199 if ((kmflags & KM_PAGEABLE) == 0) { 2200 /* 2201 * Wiring. 2202 * 2203 * 1. Holding the write lock, we create any shadow or zero-fill 2204 * objects that need to be created. Then we clip each map 2205 * entry to the region to be wired and increment its wiring 2206 * count. We create objects before clipping the map entries 2207 * to avoid object proliferation. 2208 * 2209 * 2. We downgrade to a read lock, and call vm_fault_wire to 2210 * fault in the pages for any newly wired area (wired_count is 2211 * 1). 2212 * 2213 * Downgrading to a read lock for vm_fault_wire avoids a 2214 * possible deadlock with another process that may have faulted 2215 * on one of the pages to be wired (it would mark the page busy, 2216 * blocking us, then in turn block on the map lock that we 2217 * hold). Because of problems in the recursive lock package, 2218 * we cannot upgrade to a write lock in vm_map_lookup. Thus, 2219 * any actions that require the write lock must be done 2220 * beforehand. Because we keep the read lock on the map, the 2221 * copy-on-write status of the entries we modify here cannot 2222 * change. 2223 */ 2224 entry = start_entry; 2225 while ((entry != &map->header) && (entry->start < end)) { 2226 /* 2227 * Trivial case if the entry is already wired 2228 */ 2229 if (entry->wired_count) { 2230 entry->wired_count++; 2231 entry = entry->next; 2232 continue; 2233 } 2234 2235 /* 2236 * The entry is being newly wired, we have to setup 2237 * appropriate management structures. A shadow 2238 * object is required for a copy-on-write region, 2239 * or a normal object for a zero-fill region. We 2240 * do not have to do this for entries that point to sub 2241 * maps because we won't hold the lock on the sub map. 2242 */ 2243 if (entry->maptype != VM_MAPTYPE_SUBMAP) { 2244 int copyflag = entry->eflags & 2245 MAP_ENTRY_NEEDS_COPY; 2246 if (copyflag && ((entry->protection & 2247 VM_PROT_WRITE) != 0)) { 2248 vm_map_entry_shadow(entry); 2249 } else if (entry->object.vm_object == NULL && 2250 !map->system_map) { 2251 vm_map_entry_allocate_object(entry); 2252 } 2253 } 2254 2255 entry->wired_count++; 2256 entry = entry->next; 2257 } 2258 2259 /* 2260 * Pass 2. 2261 */ 2262 2263 /* 2264 * HACK HACK HACK HACK 2265 * 2266 * vm_fault_wire() temporarily unlocks the map to avoid 2267 * deadlocks. The in-transition flag from vm_map_clip_range 2268 * call should protect us from changes while the map is 2269 * unlocked. T 2270 * 2271 * NOTE: Previously this comment stated that clipping might 2272 * still occur while the entry is unlocked, but from 2273 * what I can tell it actually cannot. 2274 * 2275 * It is unclear whether the CLIP_CHECK_*() calls 2276 * are still needed but we keep them in anyway. 2277 * 2278 * HACK HACK HACK HACK 2279 */ 2280 2281 entry = start_entry; 2282 while (entry != &map->header && entry->start < end) { 2283 /* 2284 * If vm_fault_wire fails for any page we need to undo 2285 * what has been done. We decrement the wiring count 2286 * for those pages which have not yet been wired (now) 2287 * and unwire those that have (later). 2288 */ 2289 vm_offset_t save_start = entry->start; 2290 vm_offset_t save_end = entry->end; 2291 2292 if (entry->wired_count == 1) 2293 rv = vm_fault_wire(map, entry, FALSE); 2294 if (rv) { 2295 CLIP_CHECK_BACK(entry, save_start); 2296 for (;;) { 2297 KASSERT(entry->wired_count == 1, ("wired_count changed unexpectedly")); 2298 entry->wired_count = 0; 2299 if (entry->end == save_end) 2300 break; 2301 entry = entry->next; 2302 KASSERT(entry != &map->header, ("bad entry clip during backout")); 2303 } 2304 end = save_start; 2305 break; 2306 } 2307 CLIP_CHECK_FWD(entry, save_end); 2308 entry = entry->next; 2309 } 2310 2311 /* 2312 * If a failure occured undo everything by falling through 2313 * to the unwiring code. 'end' has already been adjusted 2314 * appropriately. 2315 */ 2316 if (rv) 2317 kmflags |= KM_PAGEABLE; 2318 2319 /* 2320 * start_entry is still IN_TRANSITION but may have been 2321 * clipped since vm_fault_wire() unlocks and relocks the 2322 * map. No matter how clipped it has gotten there should 2323 * be a fragment that is on our start boundary. 2324 */ 2325 CLIP_CHECK_BACK(start_entry, start); 2326 } 2327 2328 if (kmflags & KM_PAGEABLE) { 2329 /* 2330 * This is the unwiring case. We must first ensure that the 2331 * range to be unwired is really wired down. We know there 2332 * are no holes. 2333 */ 2334 entry = start_entry; 2335 while ((entry != &map->header) && (entry->start < end)) { 2336 if (entry->wired_count == 0) { 2337 rv = KERN_INVALID_ARGUMENT; 2338 goto done; 2339 } 2340 entry = entry->next; 2341 } 2342 2343 /* 2344 * Now decrement the wiring count for each region. If a region 2345 * becomes completely unwired, unwire its physical pages and 2346 * mappings. 2347 */ 2348 entry = start_entry; 2349 while ((entry != &map->header) && (entry->start < end)) { 2350 entry->wired_count--; 2351 if (entry->wired_count == 0) 2352 vm_fault_unwire(map, entry); 2353 entry = entry->next; 2354 } 2355 } 2356 done: 2357 vm_map_unclip_range(map, start_entry, start, real_end, 2358 &count, MAP_CLIP_NO_HOLES); 2359 map->timestamp++; 2360 vm_map_unlock(map); 2361 failure: 2362 if (kmflags & KM_KRESERVE) 2363 vm_map_entry_krelease(count); 2364 else 2365 vm_map_entry_release(count); 2366 return (rv); 2367 } 2368 2369 /* 2370 * Mark a newly allocated address range as wired but do not fault in 2371 * the pages. The caller is expected to load the pages into the object. 2372 * 2373 * The map must be locked on entry and will remain locked on return. 2374 * No other requirements. 2375 */ 2376 void 2377 vm_map_set_wired_quick(vm_map_t map, vm_offset_t addr, vm_size_t size, 2378 int *countp) 2379 { 2380 vm_map_entry_t scan; 2381 vm_map_entry_t entry; 2382 2383 entry = vm_map_clip_range(map, addr, addr + size, 2384 countp, MAP_CLIP_NO_HOLES); 2385 for (scan = entry; 2386 scan != &map->header && scan->start < addr + size; 2387 scan = scan->next) { 2388 KKASSERT(entry->wired_count == 0); 2389 entry->wired_count = 1; 2390 } 2391 vm_map_unclip_range(map, entry, addr, addr + size, 2392 countp, MAP_CLIP_NO_HOLES); 2393 } 2394 2395 /* 2396 * Push any dirty cached pages in the address range to their pager. 2397 * If syncio is TRUE, dirty pages are written synchronously. 2398 * If invalidate is TRUE, any cached pages are freed as well. 2399 * 2400 * This routine is called by sys_msync() 2401 * 2402 * Returns an error if any part of the specified range is not mapped. 2403 * 2404 * No requirements. 2405 */ 2406 int 2407 vm_map_clean(vm_map_t map, vm_offset_t start, vm_offset_t end, 2408 boolean_t syncio, boolean_t invalidate) 2409 { 2410 vm_map_entry_t current; 2411 vm_map_entry_t entry; 2412 vm_size_t size; 2413 vm_object_t object; 2414 vm_ooffset_t offset; 2415 2416 vm_map_lock_read(map); 2417 VM_MAP_RANGE_CHECK(map, start, end); 2418 if (!vm_map_lookup_entry(map, start, &entry)) { 2419 vm_map_unlock_read(map); 2420 return (KERN_INVALID_ADDRESS); 2421 } 2422 /* 2423 * Make a first pass to check for holes. 2424 */ 2425 for (current = entry; current->start < end; current = current->next) { 2426 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2427 vm_map_unlock_read(map); 2428 return (KERN_INVALID_ARGUMENT); 2429 } 2430 if (end > current->end && 2431 (current->next == &map->header || 2432 current->end != current->next->start)) { 2433 vm_map_unlock_read(map); 2434 return (KERN_INVALID_ADDRESS); 2435 } 2436 } 2437 2438 if (invalidate) 2439 pmap_remove(vm_map_pmap(map), start, end); 2440 2441 /* 2442 * Make a second pass, cleaning/uncaching pages from the indicated 2443 * objects as we go. 2444 * 2445 * Hold vm_token to avoid blocking in vm_object_reference() 2446 */ 2447 lwkt_gettoken(&vm_token); 2448 lwkt_gettoken(&vmobj_token); 2449 2450 for (current = entry; current->start < end; current = current->next) { 2451 offset = current->offset + (start - current->start); 2452 size = (end <= current->end ? end : current->end) - start; 2453 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2454 vm_map_t smap; 2455 vm_map_entry_t tentry; 2456 vm_size_t tsize; 2457 2458 smap = current->object.sub_map; 2459 vm_map_lock_read(smap); 2460 vm_map_lookup_entry(smap, offset, &tentry); 2461 tsize = tentry->end - offset; 2462 if (tsize < size) 2463 size = tsize; 2464 object = tentry->object.vm_object; 2465 offset = tentry->offset + (offset - tentry->start); 2466 vm_map_unlock_read(smap); 2467 } else { 2468 object = current->object.vm_object; 2469 } 2470 /* 2471 * Note that there is absolutely no sense in writing out 2472 * anonymous objects, so we track down the vnode object 2473 * to write out. 2474 * We invalidate (remove) all pages from the address space 2475 * anyway, for semantic correctness. 2476 * 2477 * note: certain anonymous maps, such as MAP_NOSYNC maps, 2478 * may start out with a NULL object. 2479 */ 2480 while (object && object->backing_object) { 2481 offset += object->backing_object_offset; 2482 object = object->backing_object; 2483 if (object->size < OFF_TO_IDX( offset + size)) 2484 size = IDX_TO_OFF(object->size) - offset; 2485 } 2486 if (object && (object->type == OBJT_VNODE) && 2487 (current->protection & VM_PROT_WRITE) && 2488 (object->flags & OBJ_NOMSYNC) == 0) { 2489 /* 2490 * Flush pages if writing is allowed, invalidate them 2491 * if invalidation requested. Pages undergoing I/O 2492 * will be ignored by vm_object_page_remove(). 2493 * 2494 * We cannot lock the vnode and then wait for paging 2495 * to complete without deadlocking against vm_fault. 2496 * Instead we simply call vm_object_page_remove() and 2497 * allow it to block internally on a page-by-page 2498 * basis when it encounters pages undergoing async 2499 * I/O. 2500 */ 2501 int flags; 2502 2503 vm_object_reference_locked(object); 2504 vn_lock(object->handle, LK_EXCLUSIVE | LK_RETRY); 2505 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 2506 flags |= invalidate ? OBJPC_INVAL : 0; 2507 2508 /* 2509 * When operating on a virtual page table just 2510 * flush the whole object. XXX we probably ought 2511 * to 2512 */ 2513 switch(current->maptype) { 2514 case VM_MAPTYPE_NORMAL: 2515 vm_object_page_clean(object, 2516 OFF_TO_IDX(offset), 2517 OFF_TO_IDX(offset + size + PAGE_MASK), 2518 flags); 2519 break; 2520 case VM_MAPTYPE_VPAGETABLE: 2521 vm_object_page_clean(object, 0, 0, flags); 2522 break; 2523 } 2524 vn_unlock(((struct vnode *)object->handle)); 2525 vm_object_deallocate_locked(object); 2526 } 2527 if (object && invalidate && 2528 ((object->type == OBJT_VNODE) || 2529 (object->type == OBJT_DEVICE))) { 2530 int clean_only = 2531 (object->type == OBJT_DEVICE) ? FALSE : TRUE; 2532 vm_object_reference_locked(object); 2533 switch(current->maptype) { 2534 case VM_MAPTYPE_NORMAL: 2535 vm_object_page_remove(object, 2536 OFF_TO_IDX(offset), 2537 OFF_TO_IDX(offset + size + PAGE_MASK), 2538 clean_only); 2539 break; 2540 case VM_MAPTYPE_VPAGETABLE: 2541 vm_object_page_remove(object, 0, 0, clean_only); 2542 break; 2543 } 2544 vm_object_deallocate_locked(object); 2545 } 2546 start += size; 2547 } 2548 2549 lwkt_reltoken(&vmobj_token); 2550 lwkt_reltoken(&vm_token); 2551 vm_map_unlock_read(map); 2552 2553 return (KERN_SUCCESS); 2554 } 2555 2556 /* 2557 * Make the region specified by this entry pageable. 2558 * 2559 * The vm_map must be exclusively locked. 2560 */ 2561 static void 2562 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) 2563 { 2564 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2565 entry->wired_count = 0; 2566 vm_fault_unwire(map, entry); 2567 } 2568 2569 /* 2570 * Deallocate the given entry from the target map. 2571 * 2572 * The vm_map must be exclusively locked. 2573 */ 2574 static void 2575 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry, int *countp) 2576 { 2577 vm_map_entry_unlink(map, entry); 2578 map->size -= entry->end - entry->start; 2579 2580 switch(entry->maptype) { 2581 case VM_MAPTYPE_NORMAL: 2582 case VM_MAPTYPE_VPAGETABLE: 2583 vm_object_deallocate(entry->object.vm_object); 2584 break; 2585 default: 2586 break; 2587 } 2588 2589 vm_map_entry_dispose(map, entry, countp); 2590 } 2591 2592 /* 2593 * Deallocates the given address range from the target map. 2594 * 2595 * The vm_map must be exclusively locked. 2596 */ 2597 int 2598 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end, int *countp) 2599 { 2600 vm_object_t object; 2601 vm_map_entry_t entry; 2602 vm_map_entry_t first_entry; 2603 2604 ASSERT_VM_MAP_LOCKED(map); 2605 again: 2606 /* 2607 * Find the start of the region, and clip it. Set entry to point 2608 * at the first record containing the requested address or, if no 2609 * such record exists, the next record with a greater address. The 2610 * loop will run from this point until a record beyond the termination 2611 * address is encountered. 2612 * 2613 * map->hint must be adjusted to not point to anything we delete, 2614 * so set it to the entry prior to the one being deleted. 2615 * 2616 * GGG see other GGG comment. 2617 */ 2618 if (vm_map_lookup_entry(map, start, &first_entry)) { 2619 entry = first_entry; 2620 vm_map_clip_start(map, entry, start, countp); 2621 map->hint = entry->prev; /* possible problem XXX */ 2622 } else { 2623 map->hint = first_entry; /* possible problem XXX */ 2624 entry = first_entry->next; 2625 } 2626 2627 /* 2628 * If a hole opens up prior to the current first_free then 2629 * adjust first_free. As with map->hint, map->first_free 2630 * cannot be left set to anything we might delete. 2631 */ 2632 if (entry == &map->header) { 2633 map->first_free = &map->header; 2634 } else if (map->first_free->start >= start) { 2635 map->first_free = entry->prev; 2636 } 2637 2638 /* 2639 * Step through all entries in this region 2640 */ 2641 while ((entry != &map->header) && (entry->start < end)) { 2642 vm_map_entry_t next; 2643 vm_offset_t s, e; 2644 vm_pindex_t offidxstart, offidxend, count; 2645 2646 /* 2647 * If we hit an in-transition entry we have to sleep and 2648 * retry. It's easier (and not really slower) to just retry 2649 * since this case occurs so rarely and the hint is already 2650 * pointing at the right place. We have to reset the 2651 * start offset so as not to accidently delete an entry 2652 * another process just created in vacated space. 2653 */ 2654 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 2655 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 2656 start = entry->start; 2657 ++mycpu->gd_cnt.v_intrans_coll; 2658 ++mycpu->gd_cnt.v_intrans_wait; 2659 vm_map_transition_wait(map); 2660 goto again; 2661 } 2662 vm_map_clip_end(map, entry, end, countp); 2663 2664 s = entry->start; 2665 e = entry->end; 2666 next = entry->next; 2667 2668 offidxstart = OFF_TO_IDX(entry->offset); 2669 count = OFF_TO_IDX(e - s); 2670 object = entry->object.vm_object; 2671 2672 /* 2673 * Unwire before removing addresses from the pmap; otherwise, 2674 * unwiring will put the entries back in the pmap. 2675 */ 2676 if (entry->wired_count != 0) 2677 vm_map_entry_unwire(map, entry); 2678 2679 offidxend = offidxstart + count; 2680 2681 /* 2682 * Hold vm_token when manipulating vm_objects, 2683 * 2684 * Hold vmobj_token when potentially adding or removing 2685 * objects (collapse requires both). 2686 */ 2687 lwkt_gettoken(&vm_token); 2688 lwkt_gettoken(&vmobj_token); 2689 2690 if (object == &kernel_object) { 2691 vm_object_page_remove(object, offidxstart, 2692 offidxend, FALSE); 2693 } else { 2694 pmap_remove(map->pmap, s, e); 2695 2696 if (object != NULL && 2697 object->ref_count != 1 && 2698 (object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == 2699 OBJ_ONEMAPPING && 2700 (object->type == OBJT_DEFAULT || 2701 object->type == OBJT_SWAP)) { 2702 vm_object_collapse(object); 2703 vm_object_page_remove(object, offidxstart, 2704 offidxend, FALSE); 2705 if (object->type == OBJT_SWAP) { 2706 swap_pager_freespace(object, 2707 offidxstart, 2708 count); 2709 } 2710 if (offidxend >= object->size && 2711 offidxstart < object->size) { 2712 object->size = offidxstart; 2713 } 2714 } 2715 } 2716 lwkt_reltoken(&vmobj_token); 2717 lwkt_reltoken(&vm_token); 2718 2719 /* 2720 * Delete the entry (which may delete the object) only after 2721 * removing all pmap entries pointing to its pages. 2722 * (Otherwise, its page frames may be reallocated, and any 2723 * modify bits will be set in the wrong object!) 2724 */ 2725 vm_map_entry_delete(map, entry, countp); 2726 entry = next; 2727 } 2728 return (KERN_SUCCESS); 2729 } 2730 2731 /* 2732 * Remove the given address range from the target map. 2733 * This is the exported form of vm_map_delete. 2734 * 2735 * No requirements. 2736 */ 2737 int 2738 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) 2739 { 2740 int result; 2741 int count; 2742 2743 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2744 vm_map_lock(map); 2745 VM_MAP_RANGE_CHECK(map, start, end); 2746 result = vm_map_delete(map, start, end, &count); 2747 vm_map_unlock(map); 2748 vm_map_entry_release(count); 2749 2750 return (result); 2751 } 2752 2753 /* 2754 * Assert that the target map allows the specified privilege on the 2755 * entire address region given. The entire region must be allocated. 2756 * 2757 * The caller must specify whether the vm_map is already locked or not. 2758 */ 2759 boolean_t 2760 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, 2761 vm_prot_t protection, boolean_t have_lock) 2762 { 2763 vm_map_entry_t entry; 2764 vm_map_entry_t tmp_entry; 2765 boolean_t result; 2766 2767 if (have_lock == FALSE) 2768 vm_map_lock_read(map); 2769 2770 if (!vm_map_lookup_entry(map, start, &tmp_entry)) { 2771 if (have_lock == FALSE) 2772 vm_map_unlock_read(map); 2773 return (FALSE); 2774 } 2775 entry = tmp_entry; 2776 2777 result = TRUE; 2778 while (start < end) { 2779 if (entry == &map->header) { 2780 result = FALSE; 2781 break; 2782 } 2783 /* 2784 * No holes allowed! 2785 */ 2786 2787 if (start < entry->start) { 2788 result = FALSE; 2789 break; 2790 } 2791 /* 2792 * Check protection associated with entry. 2793 */ 2794 2795 if ((entry->protection & protection) != protection) { 2796 result = FALSE; 2797 break; 2798 } 2799 /* go to next entry */ 2800 2801 start = entry->end; 2802 entry = entry->next; 2803 } 2804 if (have_lock == FALSE) 2805 vm_map_unlock_read(map); 2806 return (result); 2807 } 2808 2809 /* 2810 * Split the pages in a map entry into a new object. This affords 2811 * easier removal of unused pages, and keeps object inheritance from 2812 * being a negative impact on memory usage. 2813 * 2814 * The vm_map must be exclusively locked. 2815 */ 2816 static void 2817 vm_map_split(vm_map_entry_t entry) 2818 { 2819 vm_page_t m; 2820 vm_object_t orig_object, new_object, source; 2821 vm_offset_t s, e; 2822 vm_pindex_t offidxstart, offidxend, idx; 2823 vm_size_t size; 2824 vm_ooffset_t offset; 2825 2826 orig_object = entry->object.vm_object; 2827 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 2828 return; 2829 if (orig_object->ref_count <= 1) 2830 return; 2831 2832 offset = entry->offset; 2833 s = entry->start; 2834 e = entry->end; 2835 2836 offidxstart = OFF_TO_IDX(offset); 2837 offidxend = offidxstart + OFF_TO_IDX(e - s); 2838 size = offidxend - offidxstart; 2839 2840 switch(orig_object->type) { 2841 case OBJT_DEFAULT: 2842 new_object = default_pager_alloc(NULL, IDX_TO_OFF(size), 2843 VM_PROT_ALL, 0); 2844 break; 2845 case OBJT_SWAP: 2846 new_object = swap_pager_alloc(NULL, IDX_TO_OFF(size), 2847 VM_PROT_ALL, 0); 2848 break; 2849 default: 2850 /* not reached */ 2851 new_object = NULL; 2852 KKASSERT(0); 2853 } 2854 if (new_object == NULL) 2855 return; 2856 2857 /* 2858 * vm_token required when manipulating vm_objects. 2859 */ 2860 lwkt_gettoken(&vm_token); 2861 lwkt_gettoken(&vmobj_token); 2862 2863 source = orig_object->backing_object; 2864 if (source != NULL) { 2865 /* Referenced by new_object */ 2866 vm_object_reference_locked(source); 2867 LIST_INSERT_HEAD(&source->shadow_head, 2868 new_object, shadow_list); 2869 vm_object_clear_flag(source, OBJ_ONEMAPPING); 2870 new_object->backing_object_offset = 2871 orig_object->backing_object_offset + 2872 IDX_TO_OFF(offidxstart); 2873 new_object->backing_object = source; 2874 source->shadow_count++; 2875 source->generation++; 2876 } 2877 2878 for (idx = 0; idx < size; idx++) { 2879 vm_page_t m; 2880 2881 retry: 2882 m = vm_page_lookup(orig_object, offidxstart + idx); 2883 if (m == NULL) 2884 continue; 2885 2886 /* 2887 * We must wait for pending I/O to complete before we can 2888 * rename the page. 2889 * 2890 * We do not have to VM_PROT_NONE the page as mappings should 2891 * not be changed by this operation. 2892 */ 2893 if (vm_page_sleep_busy(m, TRUE, "spltwt")) 2894 goto retry; 2895 vm_page_busy(m); 2896 vm_page_rename(m, new_object, idx); 2897 /* page automatically made dirty by rename and cache handled */ 2898 vm_page_busy(m); 2899 } 2900 2901 if (orig_object->type == OBJT_SWAP) { 2902 vm_object_pip_add(orig_object, 1); 2903 /* 2904 * copy orig_object pages into new_object 2905 * and destroy unneeded pages in 2906 * shadow object. 2907 */ 2908 swap_pager_copy(orig_object, new_object, offidxstart, 0); 2909 vm_object_pip_wakeup(orig_object); 2910 } 2911 2912 /* 2913 * Wakeup the pages we played with. No spl protection is needed 2914 * for a simple wakeup. 2915 */ 2916 for (idx = 0; idx < size; idx++) { 2917 m = vm_page_lookup(new_object, idx); 2918 if (m) 2919 vm_page_wakeup(m); 2920 } 2921 2922 entry->object.vm_object = new_object; 2923 entry->offset = 0LL; 2924 vm_object_deallocate_locked(orig_object); 2925 lwkt_reltoken(&vmobj_token); 2926 lwkt_reltoken(&vm_token); 2927 } 2928 2929 /* 2930 * Copies the contents of the source entry to the destination 2931 * entry. The entries *must* be aligned properly. 2932 * 2933 * The vm_map must be exclusively locked. 2934 * vm_token must be held 2935 */ 2936 static void 2937 vm_map_copy_entry(vm_map_t src_map, vm_map_t dst_map, 2938 vm_map_entry_t src_entry, vm_map_entry_t dst_entry) 2939 { 2940 vm_object_t src_object; 2941 2942 if (dst_entry->maptype == VM_MAPTYPE_SUBMAP) 2943 return; 2944 if (src_entry->maptype == VM_MAPTYPE_SUBMAP) 2945 return; 2946 2947 ASSERT_LWKT_TOKEN_HELD(&vm_token); 2948 lwkt_gettoken(&vmobj_token); /* required for collapse */ 2949 2950 if (src_entry->wired_count == 0) { 2951 /* 2952 * If the source entry is marked needs_copy, it is already 2953 * write-protected. 2954 */ 2955 if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) { 2956 pmap_protect(src_map->pmap, 2957 src_entry->start, 2958 src_entry->end, 2959 src_entry->protection & ~VM_PROT_WRITE); 2960 } 2961 2962 /* 2963 * Make a copy of the object. 2964 */ 2965 if ((src_object = src_entry->object.vm_object) != NULL) { 2966 if ((src_object->handle == NULL) && 2967 (src_object->type == OBJT_DEFAULT || 2968 src_object->type == OBJT_SWAP)) { 2969 vm_object_collapse(src_object); 2970 if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) { 2971 vm_map_split(src_entry); 2972 src_object = src_entry->object.vm_object; 2973 } 2974 } 2975 2976 vm_object_reference_locked(src_object); 2977 vm_object_clear_flag(src_object, OBJ_ONEMAPPING); 2978 dst_entry->object.vm_object = src_object; 2979 src_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); 2980 dst_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); 2981 dst_entry->offset = src_entry->offset; 2982 } else { 2983 dst_entry->object.vm_object = NULL; 2984 dst_entry->offset = 0; 2985 } 2986 2987 pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start, 2988 dst_entry->end - dst_entry->start, src_entry->start); 2989 } else { 2990 /* 2991 * Of course, wired down pages can't be set copy-on-write. 2992 * Cause wired pages to be copied into the new map by 2993 * simulating faults (the new pages are pageable) 2994 */ 2995 vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry); 2996 } 2997 lwkt_reltoken(&vmobj_token); 2998 } 2999 3000 /* 3001 * vmspace_fork: 3002 * Create a new process vmspace structure and vm_map 3003 * based on those of an existing process. The new map 3004 * is based on the old map, according to the inheritance 3005 * values on the regions in that map. 3006 * 3007 * The source map must not be locked. 3008 * No requirements. 3009 */ 3010 struct vmspace * 3011 vmspace_fork(struct vmspace *vm1) 3012 { 3013 struct vmspace *vm2; 3014 vm_map_t old_map = &vm1->vm_map; 3015 vm_map_t new_map; 3016 vm_map_entry_t old_entry; 3017 vm_map_entry_t new_entry; 3018 vm_object_t object; 3019 int count; 3020 3021 lwkt_gettoken(&vm_token); 3022 lwkt_gettoken(&vmspace_token); 3023 lwkt_gettoken(&vmobj_token); 3024 vm_map_lock(old_map); 3025 old_map->infork = 1; 3026 3027 /* 3028 * XXX Note: upcalls are not copied. 3029 */ 3030 vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset); 3031 bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy, 3032 (caddr_t)&vm1->vm_endcopy - (caddr_t)&vm1->vm_startcopy); 3033 new_map = &vm2->vm_map; /* XXX */ 3034 new_map->timestamp = 1; 3035 3036 vm_map_lock(new_map); 3037 3038 count = 0; 3039 old_entry = old_map->header.next; 3040 while (old_entry != &old_map->header) { 3041 ++count; 3042 old_entry = old_entry->next; 3043 } 3044 3045 count = vm_map_entry_reserve(count + MAP_RESERVE_COUNT); 3046 3047 old_entry = old_map->header.next; 3048 while (old_entry != &old_map->header) { 3049 if (old_entry->maptype == VM_MAPTYPE_SUBMAP) 3050 panic("vm_map_fork: encountered a submap"); 3051 3052 switch (old_entry->inheritance) { 3053 case VM_INHERIT_NONE: 3054 break; 3055 case VM_INHERIT_SHARE: 3056 /* 3057 * Clone the entry, creating the shared object if 3058 * necessary. 3059 */ 3060 object = old_entry->object.vm_object; 3061 if (object == NULL) { 3062 vm_map_entry_allocate_object(old_entry); 3063 object = old_entry->object.vm_object; 3064 } 3065 3066 /* 3067 * Add the reference before calling vm_map_entry_shadow 3068 * to insure that a shadow object is created. 3069 */ 3070 vm_object_reference_locked(object); 3071 if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3072 vm_map_entry_shadow(old_entry); 3073 /* Transfer the second reference too. */ 3074 vm_object_reference_locked( 3075 old_entry->object.vm_object); 3076 vm_object_deallocate_locked(object); 3077 object = old_entry->object.vm_object; 3078 } 3079 vm_object_clear_flag(object, OBJ_ONEMAPPING); 3080 3081 /* 3082 * Clone the entry, referencing the shared object. 3083 */ 3084 new_entry = vm_map_entry_create(new_map, &count); 3085 *new_entry = *old_entry; 3086 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3087 new_entry->wired_count = 0; 3088 3089 /* 3090 * Insert the entry into the new map -- we know we're 3091 * inserting at the end of the new map. 3092 */ 3093 3094 vm_map_entry_link(new_map, new_map->header.prev, 3095 new_entry); 3096 3097 /* 3098 * Update the physical map 3099 */ 3100 pmap_copy(new_map->pmap, old_map->pmap, 3101 new_entry->start, 3102 (old_entry->end - old_entry->start), 3103 old_entry->start); 3104 break; 3105 case VM_INHERIT_COPY: 3106 /* 3107 * Clone the entry and link into the map. 3108 */ 3109 new_entry = vm_map_entry_create(new_map, &count); 3110 *new_entry = *old_entry; 3111 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3112 new_entry->wired_count = 0; 3113 new_entry->object.vm_object = NULL; 3114 vm_map_entry_link(new_map, new_map->header.prev, 3115 new_entry); 3116 vm_map_copy_entry(old_map, new_map, old_entry, 3117 new_entry); 3118 break; 3119 } 3120 old_entry = old_entry->next; 3121 } 3122 3123 new_map->size = old_map->size; 3124 old_map->infork = 0; 3125 vm_map_unlock(old_map); 3126 vm_map_unlock(new_map); 3127 vm_map_entry_release(count); 3128 3129 lwkt_reltoken(&vmobj_token); 3130 lwkt_reltoken(&vmspace_token); 3131 lwkt_reltoken(&vm_token); 3132 3133 return (vm2); 3134 } 3135 3136 /* 3137 * Create an auto-grow stack entry 3138 * 3139 * No requirements. 3140 */ 3141 int 3142 vm_map_stack (vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, 3143 int flags, vm_prot_t prot, vm_prot_t max, int cow) 3144 { 3145 vm_map_entry_t prev_entry; 3146 vm_map_entry_t new_stack_entry; 3147 vm_size_t init_ssize; 3148 int rv; 3149 int count; 3150 vm_offset_t tmpaddr; 3151 3152 cow |= MAP_IS_STACK; 3153 3154 if (max_ssize < sgrowsiz) 3155 init_ssize = max_ssize; 3156 else 3157 init_ssize = sgrowsiz; 3158 3159 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3160 vm_map_lock(map); 3161 3162 /* 3163 * Find space for the mapping 3164 */ 3165 if ((flags & (MAP_FIXED | MAP_TRYFIXED)) == 0) { 3166 if (vm_map_findspace(map, addrbos, max_ssize, 1, 3167 flags, &tmpaddr)) { 3168 vm_map_unlock(map); 3169 vm_map_entry_release(count); 3170 return (KERN_NO_SPACE); 3171 } 3172 addrbos = tmpaddr; 3173 } 3174 3175 /* If addr is already mapped, no go */ 3176 if (vm_map_lookup_entry(map, addrbos, &prev_entry)) { 3177 vm_map_unlock(map); 3178 vm_map_entry_release(count); 3179 return (KERN_NO_SPACE); 3180 } 3181 3182 #if 0 3183 /* XXX already handled by kern_mmap() */ 3184 /* If we would blow our VMEM resource limit, no go */ 3185 if (map->size + init_ssize > 3186 curproc->p_rlimit[RLIMIT_VMEM].rlim_cur) { 3187 vm_map_unlock(map); 3188 vm_map_entry_release(count); 3189 return (KERN_NO_SPACE); 3190 } 3191 #endif 3192 3193 /* 3194 * If we can't accomodate max_ssize in the current mapping, 3195 * no go. However, we need to be aware that subsequent user 3196 * mappings might map into the space we have reserved for 3197 * stack, and currently this space is not protected. 3198 * 3199 * Hopefully we will at least detect this condition 3200 * when we try to grow the stack. 3201 */ 3202 if ((prev_entry->next != &map->header) && 3203 (prev_entry->next->start < addrbos + max_ssize)) { 3204 vm_map_unlock(map); 3205 vm_map_entry_release(count); 3206 return (KERN_NO_SPACE); 3207 } 3208 3209 /* 3210 * We initially map a stack of only init_ssize. We will 3211 * grow as needed later. Since this is to be a grow 3212 * down stack, we map at the top of the range. 3213 * 3214 * Note: we would normally expect prot and max to be 3215 * VM_PROT_ALL, and cow to be 0. Possibly we should 3216 * eliminate these as input parameters, and just 3217 * pass these values here in the insert call. 3218 */ 3219 rv = vm_map_insert(map, &count, 3220 NULL, 0, addrbos + max_ssize - init_ssize, 3221 addrbos + max_ssize, 3222 VM_MAPTYPE_NORMAL, 3223 prot, max, 3224 cow); 3225 3226 /* Now set the avail_ssize amount */ 3227 if (rv == KERN_SUCCESS) { 3228 if (prev_entry != &map->header) 3229 vm_map_clip_end(map, prev_entry, addrbos + max_ssize - init_ssize, &count); 3230 new_stack_entry = prev_entry->next; 3231 if (new_stack_entry->end != addrbos + max_ssize || 3232 new_stack_entry->start != addrbos + max_ssize - init_ssize) 3233 panic ("Bad entry start/end for new stack entry"); 3234 else 3235 new_stack_entry->aux.avail_ssize = max_ssize - init_ssize; 3236 } 3237 3238 vm_map_unlock(map); 3239 vm_map_entry_release(count); 3240 return (rv); 3241 } 3242 3243 /* 3244 * Attempts to grow a vm stack entry. Returns KERN_SUCCESS if the 3245 * desired address is already mapped, or if we successfully grow 3246 * the stack. Also returns KERN_SUCCESS if addr is outside the 3247 * stack range (this is strange, but preserves compatibility with 3248 * the grow function in vm_machdep.c). 3249 * 3250 * No requirements. 3251 */ 3252 int 3253 vm_map_growstack (struct proc *p, vm_offset_t addr) 3254 { 3255 vm_map_entry_t prev_entry; 3256 vm_map_entry_t stack_entry; 3257 vm_map_entry_t new_stack_entry; 3258 struct vmspace *vm = p->p_vmspace; 3259 vm_map_t map = &vm->vm_map; 3260 vm_offset_t end; 3261 int grow_amount; 3262 int rv = KERN_SUCCESS; 3263 int is_procstack; 3264 int use_read_lock = 1; 3265 int count; 3266 3267 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3268 Retry: 3269 if (use_read_lock) 3270 vm_map_lock_read(map); 3271 else 3272 vm_map_lock(map); 3273 3274 /* If addr is already in the entry range, no need to grow.*/ 3275 if (vm_map_lookup_entry(map, addr, &prev_entry)) 3276 goto done; 3277 3278 if ((stack_entry = prev_entry->next) == &map->header) 3279 goto done; 3280 if (prev_entry == &map->header) 3281 end = stack_entry->start - stack_entry->aux.avail_ssize; 3282 else 3283 end = prev_entry->end; 3284 3285 /* 3286 * This next test mimics the old grow function in vm_machdep.c. 3287 * It really doesn't quite make sense, but we do it anyway 3288 * for compatibility. 3289 * 3290 * If not growable stack, return success. This signals the 3291 * caller to proceed as he would normally with normal vm. 3292 */ 3293 if (stack_entry->aux.avail_ssize < 1 || 3294 addr >= stack_entry->start || 3295 addr < stack_entry->start - stack_entry->aux.avail_ssize) { 3296 goto done; 3297 } 3298 3299 /* Find the minimum grow amount */ 3300 grow_amount = roundup (stack_entry->start - addr, PAGE_SIZE); 3301 if (grow_amount > stack_entry->aux.avail_ssize) { 3302 rv = KERN_NO_SPACE; 3303 goto done; 3304 } 3305 3306 /* 3307 * If there is no longer enough space between the entries 3308 * nogo, and adjust the available space. Note: this 3309 * should only happen if the user has mapped into the 3310 * stack area after the stack was created, and is 3311 * probably an error. 3312 * 3313 * This also effectively destroys any guard page the user 3314 * might have intended by limiting the stack size. 3315 */ 3316 if (grow_amount > stack_entry->start - end) { 3317 if (use_read_lock && vm_map_lock_upgrade(map)) { 3318 use_read_lock = 0; 3319 goto Retry; 3320 } 3321 use_read_lock = 0; 3322 stack_entry->aux.avail_ssize = stack_entry->start - end; 3323 rv = KERN_NO_SPACE; 3324 goto done; 3325 } 3326 3327 is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr; 3328 3329 /* If this is the main process stack, see if we're over the 3330 * stack limit. 3331 */ 3332 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > 3333 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 3334 rv = KERN_NO_SPACE; 3335 goto done; 3336 } 3337 3338 /* Round up the grow amount modulo SGROWSIZ */ 3339 grow_amount = roundup (grow_amount, sgrowsiz); 3340 if (grow_amount > stack_entry->aux.avail_ssize) { 3341 grow_amount = stack_entry->aux.avail_ssize; 3342 } 3343 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > 3344 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 3345 grow_amount = p->p_rlimit[RLIMIT_STACK].rlim_cur - 3346 ctob(vm->vm_ssize); 3347 } 3348 3349 /* If we would blow our VMEM resource limit, no go */ 3350 if (map->size + grow_amount > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { 3351 rv = KERN_NO_SPACE; 3352 goto done; 3353 } 3354 3355 if (use_read_lock && vm_map_lock_upgrade(map)) { 3356 use_read_lock = 0; 3357 goto Retry; 3358 } 3359 use_read_lock = 0; 3360 3361 /* Get the preliminary new entry start value */ 3362 addr = stack_entry->start - grow_amount; 3363 3364 /* If this puts us into the previous entry, cut back our growth 3365 * to the available space. Also, see the note above. 3366 */ 3367 if (addr < end) { 3368 stack_entry->aux.avail_ssize = stack_entry->start - end; 3369 addr = end; 3370 } 3371 3372 rv = vm_map_insert(map, &count, 3373 NULL, 0, addr, stack_entry->start, 3374 VM_MAPTYPE_NORMAL, 3375 VM_PROT_ALL, VM_PROT_ALL, 3376 0); 3377 3378 /* Adjust the available stack space by the amount we grew. */ 3379 if (rv == KERN_SUCCESS) { 3380 if (prev_entry != &map->header) 3381 vm_map_clip_end(map, prev_entry, addr, &count); 3382 new_stack_entry = prev_entry->next; 3383 if (new_stack_entry->end != stack_entry->start || 3384 new_stack_entry->start != addr) 3385 panic ("Bad stack grow start/end in new stack entry"); 3386 else { 3387 new_stack_entry->aux.avail_ssize = 3388 stack_entry->aux.avail_ssize - 3389 (new_stack_entry->end - new_stack_entry->start); 3390 if (is_procstack) 3391 vm->vm_ssize += btoc(new_stack_entry->end - 3392 new_stack_entry->start); 3393 } 3394 } 3395 3396 done: 3397 if (use_read_lock) 3398 vm_map_unlock_read(map); 3399 else 3400 vm_map_unlock(map); 3401 vm_map_entry_release(count); 3402 return (rv); 3403 } 3404 3405 /* 3406 * Unshare the specified VM space for exec. If other processes are 3407 * mapped to it, then create a new one. The new vmspace is null. 3408 * 3409 * No requirements. 3410 */ 3411 void 3412 vmspace_exec(struct proc *p, struct vmspace *vmcopy) 3413 { 3414 struct vmspace *oldvmspace = p->p_vmspace; 3415 struct vmspace *newvmspace; 3416 vm_map_t map = &p->p_vmspace->vm_map; 3417 3418 /* 3419 * If we are execing a resident vmspace we fork it, otherwise 3420 * we create a new vmspace. Note that exitingcnt and upcalls 3421 * are not copied to the new vmspace. 3422 */ 3423 lwkt_gettoken(&vmspace_token); 3424 if (vmcopy) { 3425 newvmspace = vmspace_fork(vmcopy); 3426 } else { 3427 newvmspace = vmspace_alloc(map->min_offset, map->max_offset); 3428 bcopy(&oldvmspace->vm_startcopy, &newvmspace->vm_startcopy, 3429 (caddr_t)&oldvmspace->vm_endcopy - 3430 (caddr_t)&oldvmspace->vm_startcopy); 3431 } 3432 3433 /* 3434 * Finish initializing the vmspace before assigning it 3435 * to the process. The vmspace will become the current vmspace 3436 * if p == curproc. 3437 */ 3438 pmap_pinit2(vmspace_pmap(newvmspace)); 3439 pmap_replacevm(p, newvmspace, 0); 3440 sysref_put(&oldvmspace->vm_sysref); 3441 lwkt_reltoken(&vmspace_token); 3442 } 3443 3444 /* 3445 * Unshare the specified VM space for forcing COW. This 3446 * is called by rfork, for the (RFMEM|RFPROC) == 0 case. 3447 * 3448 * The exitingcnt test is not strictly necessary but has been 3449 * included for code sanity (to make the code a bit more deterministic). 3450 */ 3451 void 3452 vmspace_unshare(struct proc *p) 3453 { 3454 struct vmspace *oldvmspace = p->p_vmspace; 3455 struct vmspace *newvmspace; 3456 3457 lwkt_gettoken(&vmspace_token); 3458 if (oldvmspace->vm_sysref.refcnt == 1 && oldvmspace->vm_exitingcnt == 0) 3459 return; 3460 newvmspace = vmspace_fork(oldvmspace); 3461 pmap_pinit2(vmspace_pmap(newvmspace)); 3462 pmap_replacevm(p, newvmspace, 0); 3463 sysref_put(&oldvmspace->vm_sysref); 3464 lwkt_reltoken(&vmspace_token); 3465 } 3466 3467 /* 3468 * Finds the VM object, offset, and protection for a given virtual address 3469 * in the specified map, assuming a page fault of the type specified. 3470 * 3471 * Leaves the map in question locked for read; return values are guaranteed 3472 * until a vm_map_lookup_done call is performed. Note that the map argument 3473 * is in/out; the returned map must be used in the call to vm_map_lookup_done. 3474 * 3475 * A handle (out_entry) is returned for use in vm_map_lookup_done, to make 3476 * that fast. 3477 * 3478 * If a lookup is requested with "write protection" specified, the map may 3479 * be changed to perform virtual copying operations, although the data 3480 * referenced will remain the same. 3481 * 3482 * No requirements. 3483 */ 3484 int 3485 vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ 3486 vm_offset_t vaddr, 3487 vm_prot_t fault_typea, 3488 vm_map_entry_t *out_entry, /* OUT */ 3489 vm_object_t *object, /* OUT */ 3490 vm_pindex_t *pindex, /* OUT */ 3491 vm_prot_t *out_prot, /* OUT */ 3492 boolean_t *wired) /* OUT */ 3493 { 3494 vm_map_entry_t entry; 3495 vm_map_t map = *var_map; 3496 vm_prot_t prot; 3497 vm_prot_t fault_type = fault_typea; 3498 int use_read_lock = 1; 3499 int rv = KERN_SUCCESS; 3500 3501 RetryLookup: 3502 if (use_read_lock) 3503 vm_map_lock_read(map); 3504 else 3505 vm_map_lock(map); 3506 3507 /* 3508 * If the map has an interesting hint, try it before calling full 3509 * blown lookup routine. 3510 */ 3511 entry = map->hint; 3512 *out_entry = entry; 3513 3514 if ((entry == &map->header) || 3515 (vaddr < entry->start) || (vaddr >= entry->end)) { 3516 vm_map_entry_t tmp_entry; 3517 3518 /* 3519 * Entry was either not a valid hint, or the vaddr was not 3520 * contained in the entry, so do a full lookup. 3521 */ 3522 if (!vm_map_lookup_entry(map, vaddr, &tmp_entry)) { 3523 rv = KERN_INVALID_ADDRESS; 3524 goto done; 3525 } 3526 3527 entry = tmp_entry; 3528 *out_entry = entry; 3529 } 3530 3531 /* 3532 * Handle submaps. 3533 */ 3534 if (entry->maptype == VM_MAPTYPE_SUBMAP) { 3535 vm_map_t old_map = map; 3536 3537 *var_map = map = entry->object.sub_map; 3538 if (use_read_lock) 3539 vm_map_unlock_read(old_map); 3540 else 3541 vm_map_unlock(old_map); 3542 use_read_lock = 1; 3543 goto RetryLookup; 3544 } 3545 3546 /* 3547 * Check whether this task is allowed to have this page. 3548 * Note the special case for MAP_ENTRY_COW 3549 * pages with an override. This is to implement a forced 3550 * COW for debuggers. 3551 */ 3552 3553 if (fault_type & VM_PROT_OVERRIDE_WRITE) 3554 prot = entry->max_protection; 3555 else 3556 prot = entry->protection; 3557 3558 fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 3559 if ((fault_type & prot) != fault_type) { 3560 rv = KERN_PROTECTION_FAILURE; 3561 goto done; 3562 } 3563 3564 if ((entry->eflags & MAP_ENTRY_USER_WIRED) && 3565 (entry->eflags & MAP_ENTRY_COW) && 3566 (fault_type & VM_PROT_WRITE) && 3567 (fault_typea & VM_PROT_OVERRIDE_WRITE) == 0) { 3568 rv = KERN_PROTECTION_FAILURE; 3569 goto done; 3570 } 3571 3572 /* 3573 * If this page is not pageable, we have to get it for all possible 3574 * accesses. 3575 */ 3576 *wired = (entry->wired_count != 0); 3577 if (*wired) 3578 prot = fault_type = entry->protection; 3579 3580 /* 3581 * Virtual page tables may need to update the accessed (A) bit 3582 * in a page table entry. Upgrade the fault to a write fault for 3583 * that case if the map will support it. If the map does not support 3584 * it the page table entry simply will not be updated. 3585 */ 3586 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 3587 if (prot & VM_PROT_WRITE) 3588 fault_type |= VM_PROT_WRITE; 3589 } 3590 3591 /* 3592 * If the entry was copy-on-write, we either ... 3593 */ 3594 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3595 /* 3596 * If we want to write the page, we may as well handle that 3597 * now since we've got the map locked. 3598 * 3599 * If we don't need to write the page, we just demote the 3600 * permissions allowed. 3601 */ 3602 3603 if (fault_type & VM_PROT_WRITE) { 3604 /* 3605 * Make a new object, and place it in the object 3606 * chain. Note that no new references have appeared 3607 * -- one just moved from the map to the new 3608 * object. 3609 */ 3610 3611 if (use_read_lock && vm_map_lock_upgrade(map)) { 3612 use_read_lock = 0; 3613 goto RetryLookup; 3614 } 3615 use_read_lock = 0; 3616 3617 vm_map_entry_shadow(entry); 3618 } else { 3619 /* 3620 * We're attempting to read a copy-on-write page -- 3621 * don't allow writes. 3622 */ 3623 3624 prot &= ~VM_PROT_WRITE; 3625 } 3626 } 3627 3628 /* 3629 * Create an object if necessary. 3630 */ 3631 if (entry->object.vm_object == NULL && 3632 !map->system_map) { 3633 if (use_read_lock && vm_map_lock_upgrade(map)) { 3634 use_read_lock = 0; 3635 goto RetryLookup; 3636 } 3637 use_read_lock = 0; 3638 vm_map_entry_allocate_object(entry); 3639 } 3640 3641 /* 3642 * Return the object/offset from this entry. If the entry was 3643 * copy-on-write or empty, it has been fixed up. 3644 */ 3645 3646 *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); 3647 *object = entry->object.vm_object; 3648 3649 /* 3650 * Return whether this is the only map sharing this data. On 3651 * success we return with a read lock held on the map. On failure 3652 * we return with the map unlocked. 3653 */ 3654 *out_prot = prot; 3655 done: 3656 if (rv == KERN_SUCCESS) { 3657 if (use_read_lock == 0) 3658 vm_map_lock_downgrade(map); 3659 } else if (use_read_lock) { 3660 vm_map_unlock_read(map); 3661 } else { 3662 vm_map_unlock(map); 3663 } 3664 return (rv); 3665 } 3666 3667 /* 3668 * Releases locks acquired by a vm_map_lookup() 3669 * (according to the handle returned by that lookup). 3670 * 3671 * No other requirements. 3672 */ 3673 void 3674 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry, int count) 3675 { 3676 /* 3677 * Unlock the main-level map 3678 */ 3679 vm_map_unlock_read(map); 3680 if (count) 3681 vm_map_entry_release(count); 3682 } 3683 3684 #include "opt_ddb.h" 3685 #ifdef DDB 3686 #include <sys/kernel.h> 3687 3688 #include <ddb/ddb.h> 3689 3690 /* 3691 * Debugging only 3692 */ 3693 DB_SHOW_COMMAND(map, vm_map_print) 3694 { 3695 static int nlines; 3696 /* XXX convert args. */ 3697 vm_map_t map = (vm_map_t)addr; 3698 boolean_t full = have_addr; 3699 3700 vm_map_entry_t entry; 3701 3702 db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", 3703 (void *)map, 3704 (void *)map->pmap, map->nentries, map->timestamp); 3705 nlines++; 3706 3707 if (!full && db_indent) 3708 return; 3709 3710 db_indent += 2; 3711 for (entry = map->header.next; entry != &map->header; 3712 entry = entry->next) { 3713 db_iprintf("map entry %p: start=%p, end=%p\n", 3714 (void *)entry, (void *)entry->start, (void *)entry->end); 3715 nlines++; 3716 { 3717 static char *inheritance_name[4] = 3718 {"share", "copy", "none", "donate_copy"}; 3719 3720 db_iprintf(" prot=%x/%x/%s", 3721 entry->protection, 3722 entry->max_protection, 3723 inheritance_name[(int)(unsigned char)entry->inheritance]); 3724 if (entry->wired_count != 0) 3725 db_printf(", wired"); 3726 } 3727 if (entry->maptype == VM_MAPTYPE_SUBMAP) { 3728 /* XXX no %qd in kernel. Truncate entry->offset. */ 3729 db_printf(", share=%p, offset=0x%lx\n", 3730 (void *)entry->object.sub_map, 3731 (long)entry->offset); 3732 nlines++; 3733 if ((entry->prev == &map->header) || 3734 (entry->prev->object.sub_map != 3735 entry->object.sub_map)) { 3736 db_indent += 2; 3737 vm_map_print((db_expr_t)(intptr_t) 3738 entry->object.sub_map, 3739 full, 0, NULL); 3740 db_indent -= 2; 3741 } 3742 } else { 3743 /* XXX no %qd in kernel. Truncate entry->offset. */ 3744 db_printf(", object=%p, offset=0x%lx", 3745 (void *)entry->object.vm_object, 3746 (long)entry->offset); 3747 if (entry->eflags & MAP_ENTRY_COW) 3748 db_printf(", copy (%s)", 3749 (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); 3750 db_printf("\n"); 3751 nlines++; 3752 3753 if ((entry->prev == &map->header) || 3754 (entry->prev->object.vm_object != 3755 entry->object.vm_object)) { 3756 db_indent += 2; 3757 vm_object_print((db_expr_t)(intptr_t) 3758 entry->object.vm_object, 3759 full, 0, NULL); 3760 nlines += 4; 3761 db_indent -= 2; 3762 } 3763 } 3764 } 3765 db_indent -= 2; 3766 if (db_indent == 0) 3767 nlines = 0; 3768 } 3769 3770 /* 3771 * Debugging only 3772 */ 3773 DB_SHOW_COMMAND(procvm, procvm) 3774 { 3775 struct proc *p; 3776 3777 if (have_addr) { 3778 p = (struct proc *) addr; 3779 } else { 3780 p = curproc; 3781 } 3782 3783 db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", 3784 (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, 3785 (void *)vmspace_pmap(p->p_vmspace)); 3786 3787 vm_map_print((db_expr_t)(intptr_t)&p->p_vmspace->vm_map, 1, 0, NULL); 3788 } 3789 3790 #endif /* DDB */ 3791