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/serialize.h> 79 #include <sys/lock.h> 80 #include <sys/vmmeter.h> 81 #include <sys/mman.h> 82 #include <sys/vnode.h> 83 #include <sys/resourcevar.h> 84 #include <sys/shm.h> 85 #include <sys/tree.h> 86 #include <sys/malloc.h> 87 88 #include <vm/vm.h> 89 #include <vm/vm_param.h> 90 #include <vm/pmap.h> 91 #include <vm/vm_map.h> 92 #include <vm/vm_page.h> 93 #include <vm/vm_object.h> 94 #include <vm/vm_pager.h> 95 #include <vm/vm_kern.h> 96 #include <vm/vm_extern.h> 97 #include <vm/swap_pager.h> 98 #include <vm/vm_zone.h> 99 100 #include <sys/thread2.h> 101 #include <sys/sysref2.h> 102 #include <sys/random.h> 103 #include <sys/sysctl.h> 104 105 /* 106 * Virtual memory maps provide for the mapping, protection, and sharing 107 * of virtual memory objects. In addition, this module provides for an 108 * efficient virtual copy of memory from one map to another. 109 * 110 * Synchronization is required prior to most operations. 111 * 112 * Maps consist of an ordered doubly-linked list of simple entries. 113 * A hint and a RB tree is used to speed-up lookups. 114 * 115 * Callers looking to modify maps specify start/end addresses which cause 116 * the related map entry to be clipped if necessary, and then later 117 * recombined if the pieces remained compatible. 118 * 119 * Virtual copy operations are performed by copying VM object references 120 * from one map to another, and then marking both regions as copy-on-write. 121 */ 122 static void vmspace_terminate(struct vmspace *vm); 123 static void vmspace_lock(struct vmspace *vm); 124 static void vmspace_unlock(struct vmspace *vm); 125 static void vmspace_dtor(void *obj, void *private); 126 127 MALLOC_DEFINE(M_VMSPACE, "vmspace", "vmspace objcache backingstore"); 128 129 struct sysref_class vmspace_sysref_class = { 130 .name = "vmspace", 131 .mtype = M_VMSPACE, 132 .proto = SYSREF_PROTO_VMSPACE, 133 .offset = offsetof(struct vmspace, vm_sysref), 134 .objsize = sizeof(struct vmspace), 135 .nom_cache = 32, 136 .flags = SRC_MANAGEDINIT, 137 .dtor = vmspace_dtor, 138 .ops = { 139 .terminate = (sysref_terminate_func_t)vmspace_terminate, 140 .lock = (sysref_lock_func_t)vmspace_lock, 141 .unlock = (sysref_lock_func_t)vmspace_unlock 142 } 143 }; 144 145 /* 146 * per-cpu page table cross mappings are initialized in early boot 147 * and might require a considerable number of vm_map_entry structures. 148 */ 149 #define VMEPERCPU (MAXCPU+1) 150 151 static struct vm_zone mapentzone_store, mapzone_store; 152 static vm_zone_t mapentzone, mapzone; 153 static struct vm_object mapentobj, mapobj; 154 155 static struct vm_map_entry map_entry_init[MAX_MAPENT]; 156 static struct vm_map_entry cpu_map_entry_init[MAXCPU][VMEPERCPU]; 157 static struct vm_map map_init[MAX_KMAP]; 158 159 static int randomize_mmap; 160 SYSCTL_INT(_vm, OID_AUTO, randomize_mmap, CTLFLAG_RW, &randomize_mmap, 0, 161 "Randomize mmap offsets"); 162 163 static void vm_map_entry_shadow(vm_map_entry_t entry); 164 static vm_map_entry_t vm_map_entry_create(vm_map_t map, int *); 165 static void vm_map_entry_dispose (vm_map_t map, vm_map_entry_t entry, int *); 166 static void _vm_map_clip_end (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 167 static void _vm_map_clip_start (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 168 static void vm_map_entry_delete (vm_map_t, vm_map_entry_t, int *); 169 static void vm_map_entry_unwire (vm_map_t, vm_map_entry_t); 170 static void vm_map_copy_entry (vm_map_t, vm_map_t, vm_map_entry_t, 171 vm_map_entry_t); 172 static void vm_map_split (vm_map_entry_t); 173 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); 174 175 /* 176 * Initialize the vm_map module. Must be called before any other vm_map 177 * routines. 178 * 179 * Map and entry structures are allocated from the general purpose 180 * memory pool with some exceptions: 181 * 182 * - The kernel map is allocated statically. 183 * - Initial kernel map entries are allocated out of a static pool. 184 * 185 * These restrictions are necessary since malloc() uses the 186 * maps and requires map entries. 187 * 188 * Called from the low level boot code only. 189 */ 190 void 191 vm_map_startup(void) 192 { 193 mapzone = &mapzone_store; 194 zbootinit(mapzone, "MAP", sizeof (struct vm_map), 195 map_init, MAX_KMAP); 196 mapentzone = &mapentzone_store; 197 zbootinit(mapentzone, "MAP ENTRY", sizeof (struct vm_map_entry), 198 map_entry_init, MAX_MAPENT); 199 } 200 201 /* 202 * Called prior to any vmspace allocations. 203 * 204 * Called from the low level boot code only. 205 */ 206 void 207 vm_init2(void) 208 { 209 zinitna(mapentzone, &mapentobj, NULL, 0, 0, 210 ZONE_USE_RESERVE | ZONE_SPECIAL, 1); 211 zinitna(mapzone, &mapobj, NULL, 0, 0, 0, 1); 212 pmap_init2(); 213 vm_object_init2(); 214 } 215 216 217 /* 218 * Red black tree functions 219 * 220 * The caller must hold the related map lock. 221 */ 222 static int rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b); 223 RB_GENERATE(vm_map_rb_tree, vm_map_entry, rb_entry, rb_vm_map_compare); 224 225 /* a->start is address, and the only field has to be initialized */ 226 static int 227 rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b) 228 { 229 if (a->start < b->start) 230 return(-1); 231 else if (a->start > b->start) 232 return(1); 233 return(0); 234 } 235 236 /* 237 * Allocate a vmspace structure, including a vm_map and pmap. 238 * Initialize numerous fields. While the initial allocation is zerod, 239 * subsequence reuse from the objcache leaves elements of the structure 240 * intact (particularly the pmap), so portions must be zerod. 241 * 242 * The structure is not considered activated until we call sysref_activate(). 243 * 244 * No requirements. 245 */ 246 struct vmspace * 247 vmspace_alloc(vm_offset_t min, vm_offset_t max) 248 { 249 struct vmspace *vm; 250 251 lwkt_gettoken(&vmspace_token); 252 vm = sysref_alloc(&vmspace_sysref_class); 253 bzero(&vm->vm_startcopy, 254 (char *)&vm->vm_endcopy - (char *)&vm->vm_startcopy); 255 vm_map_init(&vm->vm_map, min, max, NULL); 256 pmap_pinit(vmspace_pmap(vm)); /* (some fields reused) */ 257 vm->vm_map.pmap = vmspace_pmap(vm); /* XXX */ 258 vm->vm_shm = NULL; 259 vm->vm_exitingcnt = 0; 260 cpu_vmspace_alloc(vm); 261 sysref_activate(&vm->vm_sysref); 262 lwkt_reltoken(&vmspace_token); 263 264 return (vm); 265 } 266 267 /* 268 * dtor function - Some elements of the pmap are retained in the 269 * free-cached vmspaces to improve performance. We have to clean them up 270 * here before returning the vmspace to the memory pool. 271 * 272 * No requirements. 273 */ 274 static void 275 vmspace_dtor(void *obj, void *private) 276 { 277 struct vmspace *vm = obj; 278 279 pmap_puninit(vmspace_pmap(vm)); 280 } 281 282 /* 283 * Called in two cases: 284 * 285 * (1) When the last sysref is dropped, but exitingcnt might still be 286 * non-zero. 287 * 288 * (2) When there are no sysrefs (i.e. refcnt is negative) left and the 289 * exitingcnt becomes zero 290 * 291 * sysref will not scrap the object until we call sysref_put() once more 292 * after the last ref has been dropped. 293 * 294 * Interlocked by the sysref API. 295 */ 296 static void 297 vmspace_terminate(struct vmspace *vm) 298 { 299 int count; 300 301 /* 302 * If exitingcnt is non-zero we can't get rid of the entire vmspace 303 * yet, but we can scrap user memory. 304 */ 305 lwkt_gettoken(&vmspace_token); 306 if (vm->vm_exitingcnt) { 307 shmexit(vm); 308 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_USER_ADDRESS, 309 VM_MAX_USER_ADDRESS); 310 vm_map_remove(&vm->vm_map, VM_MIN_USER_ADDRESS, 311 VM_MAX_USER_ADDRESS); 312 lwkt_reltoken(&vmspace_token); 313 return; 314 } 315 cpu_vmspace_free(vm); 316 317 /* 318 * Make sure any SysV shm is freed, it might not have in 319 * exit1() 320 */ 321 shmexit(vm); 322 323 KKASSERT(vm->vm_upcalls == NULL); 324 325 /* 326 * Lock the map, to wait out all other references to it. 327 * Delete all of the mappings and pages they hold, then call 328 * the pmap module to reclaim anything left. 329 */ 330 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 331 vm_map_lock(&vm->vm_map); 332 vm_map_delete(&vm->vm_map, vm->vm_map.min_offset, 333 vm->vm_map.max_offset, &count); 334 vm_map_unlock(&vm->vm_map); 335 vm_map_entry_release(count); 336 337 pmap_release(vmspace_pmap(vm)); 338 sysref_put(&vm->vm_sysref); 339 lwkt_reltoken(&vmspace_token); 340 } 341 342 /* 343 * vmspaces are not currently locked. 344 */ 345 static void 346 vmspace_lock(struct vmspace *vm __unused) 347 { 348 } 349 350 static void 351 vmspace_unlock(struct vmspace *vm __unused) 352 { 353 } 354 355 /* 356 * This is called during exit indicating that the vmspace is no 357 * longer in used by an exiting process, but the process has not yet 358 * been cleaned up. 359 * 360 * No requirements. 361 */ 362 void 363 vmspace_exitbump(struct vmspace *vm) 364 { 365 lwkt_gettoken(&vmspace_token); 366 ++vm->vm_exitingcnt; 367 lwkt_reltoken(&vmspace_token); 368 } 369 370 /* 371 * This is called in the wait*() handling code. The vmspace can be terminated 372 * after the last wait is finished using it. 373 * 374 * No requirements. 375 */ 376 void 377 vmspace_exitfree(struct proc *p) 378 { 379 struct vmspace *vm; 380 381 lwkt_gettoken(&vmspace_token); 382 vm = p->p_vmspace; 383 p->p_vmspace = NULL; 384 385 if (--vm->vm_exitingcnt == 0 && sysref_isinactive(&vm->vm_sysref)) 386 vmspace_terminate(vm); 387 lwkt_reltoken(&vmspace_token); 388 } 389 390 /* 391 * Swap useage is determined by taking the proportional swap used by 392 * VM objects backing the VM map. To make up for fractional losses, 393 * if the VM object has any swap use at all the associated map entries 394 * count for at least 1 swap page. 395 * 396 * No requirements. 397 */ 398 int 399 vmspace_swap_count(struct vmspace *vmspace) 400 { 401 vm_map_t map = &vmspace->vm_map; 402 vm_map_entry_t cur; 403 vm_object_t object; 404 int count = 0; 405 int n; 406 407 lwkt_gettoken(&vmspace_token); 408 for (cur = map->header.next; cur != &map->header; cur = cur->next) { 409 switch(cur->maptype) { 410 case VM_MAPTYPE_NORMAL: 411 case VM_MAPTYPE_VPAGETABLE: 412 if ((object = cur->object.vm_object) == NULL) 413 break; 414 if (object->swblock_count) { 415 n = (cur->end - cur->start) / PAGE_SIZE; 416 count += object->swblock_count * 417 SWAP_META_PAGES * n / object->size + 1; 418 } 419 break; 420 default: 421 break; 422 } 423 } 424 lwkt_reltoken(&vmspace_token); 425 return(count); 426 } 427 428 /* 429 * Calculate the approximate number of anonymous pages in use by 430 * this vmspace. To make up for fractional losses, we count each 431 * VM object as having at least 1 anonymous page. 432 * 433 * No requirements. 434 */ 435 int 436 vmspace_anonymous_count(struct vmspace *vmspace) 437 { 438 vm_map_t map = &vmspace->vm_map; 439 vm_map_entry_t cur; 440 vm_object_t object; 441 int count = 0; 442 443 lwkt_gettoken(&vmspace_token); 444 for (cur = map->header.next; cur != &map->header; cur = cur->next) { 445 switch(cur->maptype) { 446 case VM_MAPTYPE_NORMAL: 447 case VM_MAPTYPE_VPAGETABLE: 448 if ((object = cur->object.vm_object) == NULL) 449 break; 450 if (object->type != OBJT_DEFAULT && 451 object->type != OBJT_SWAP) { 452 break; 453 } 454 count += object->resident_page_count; 455 break; 456 default: 457 break; 458 } 459 } 460 lwkt_reltoken(&vmspace_token); 461 return(count); 462 } 463 464 /* 465 * Creates and returns a new empty VM map with the given physical map 466 * structure, and having the given lower and upper address bounds. 467 * 468 * No requirements. 469 */ 470 vm_map_t 471 vm_map_create(vm_map_t result, pmap_t pmap, vm_offset_t min, vm_offset_t max) 472 { 473 if (result == NULL) 474 result = zalloc(mapzone); 475 vm_map_init(result, min, max, pmap); 476 return (result); 477 } 478 479 /* 480 * Initialize an existing vm_map structure such as that in the vmspace 481 * structure. The pmap is initialized elsewhere. 482 * 483 * No requirements. 484 */ 485 void 486 vm_map_init(struct vm_map *map, vm_offset_t min, vm_offset_t max, pmap_t pmap) 487 { 488 map->header.next = map->header.prev = &map->header; 489 RB_INIT(&map->rb_root); 490 map->nentries = 0; 491 map->size = 0; 492 map->system_map = 0; 493 map->min_offset = min; 494 map->max_offset = max; 495 map->pmap = pmap; 496 map->first_free = &map->header; 497 map->hint = &map->header; 498 map->timestamp = 0; 499 map->flags = 0; 500 lockinit(&map->lock, "thrd_sleep", (hz + 9) / 10, 0); 501 TUNABLE_INT("vm.cache_vmspaces", &vmspace_sysref_class.nom_cache); 502 } 503 504 /* 505 * Shadow the vm_map_entry's object. This typically needs to be done when 506 * a write fault is taken on an entry which had previously been cloned by 507 * fork(). The shared object (which might be NULL) must become private so 508 * we add a shadow layer above it. 509 * 510 * Object allocation for anonymous mappings is defered as long as possible. 511 * When creating a shadow, however, the underlying object must be instantiated 512 * so it can be shared. 513 * 514 * If the map segment is governed by a virtual page table then it is 515 * possible to address offsets beyond the mapped area. Just allocate 516 * a maximally sized object for this case. 517 * 518 * The vm_map must be exclusively locked. 519 * No other requirements. 520 */ 521 static 522 void 523 vm_map_entry_shadow(vm_map_entry_t entry) 524 { 525 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 526 vm_object_shadow(&entry->object.vm_object, &entry->offset, 527 0x7FFFFFFF); /* XXX */ 528 } else { 529 vm_object_shadow(&entry->object.vm_object, &entry->offset, 530 atop(entry->end - entry->start)); 531 } 532 entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 533 } 534 535 /* 536 * Allocate an object for a vm_map_entry. 537 * 538 * Object allocation for anonymous mappings is defered as long as possible. 539 * This function is called when we can defer no longer, generally when a map 540 * entry might be split or forked or takes a page fault. 541 * 542 * If the map segment is governed by a virtual page table then it is 543 * possible to address offsets beyond the mapped area. Just allocate 544 * a maximally sized object for this case. 545 * 546 * The vm_map must be exclusively locked. 547 * No other requirements. 548 */ 549 void 550 vm_map_entry_allocate_object(vm_map_entry_t entry) 551 { 552 vm_object_t obj; 553 554 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 555 obj = vm_object_allocate(OBJT_DEFAULT, 0x7FFFFFFF); /* XXX */ 556 } else { 557 obj = vm_object_allocate(OBJT_DEFAULT, 558 atop(entry->end - entry->start)); 559 } 560 entry->object.vm_object = obj; 561 entry->offset = 0; 562 } 563 564 /* 565 * Set an initial negative count so the first attempt to reserve 566 * space preloads a bunch of vm_map_entry's for this cpu. Also 567 * pre-allocate 2 vm_map_entries which will be needed by zalloc() to 568 * map a new page for vm_map_entry structures. SMP systems are 569 * particularly sensitive. 570 * 571 * This routine is called in early boot so we cannot just call 572 * vm_map_entry_reserve(). 573 * 574 * Called from the low level boot code only (for each cpu) 575 */ 576 void 577 vm_map_entry_reserve_cpu_init(globaldata_t gd) 578 { 579 vm_map_entry_t entry; 580 int i; 581 582 gd->gd_vme_avail -= MAP_RESERVE_COUNT * 2; 583 entry = &cpu_map_entry_init[gd->gd_cpuid][0]; 584 for (i = 0; i < VMEPERCPU; ++i, ++entry) { 585 entry->next = gd->gd_vme_base; 586 gd->gd_vme_base = entry; 587 } 588 } 589 590 /* 591 * Reserves vm_map_entry structures so code later on can manipulate 592 * map_entry structures within a locked map without blocking trying 593 * to allocate a new vm_map_entry. 594 * 595 * No requirements. 596 */ 597 int 598 vm_map_entry_reserve(int count) 599 { 600 struct globaldata *gd = mycpu; 601 vm_map_entry_t entry; 602 603 /* 604 * Make sure we have enough structures in gd_vme_base to handle 605 * the reservation request. 606 */ 607 crit_enter(); 608 while (gd->gd_vme_avail < count) { 609 entry = zalloc(mapentzone); 610 entry->next = gd->gd_vme_base; 611 gd->gd_vme_base = entry; 612 ++gd->gd_vme_avail; 613 } 614 gd->gd_vme_avail -= count; 615 crit_exit(); 616 617 return(count); 618 } 619 620 /* 621 * Releases previously reserved vm_map_entry structures that were not 622 * used. If we have too much junk in our per-cpu cache clean some of 623 * it out. 624 * 625 * No requirements. 626 */ 627 void 628 vm_map_entry_release(int count) 629 { 630 struct globaldata *gd = mycpu; 631 vm_map_entry_t entry; 632 633 crit_enter(); 634 gd->gd_vme_avail += count; 635 while (gd->gd_vme_avail > MAP_RESERVE_SLOP) { 636 entry = gd->gd_vme_base; 637 KKASSERT(entry != NULL); 638 gd->gd_vme_base = entry->next; 639 --gd->gd_vme_avail; 640 crit_exit(); 641 zfree(mapentzone, entry); 642 crit_enter(); 643 } 644 crit_exit(); 645 } 646 647 /* 648 * Reserve map entry structures for use in kernel_map itself. These 649 * entries have *ALREADY* been reserved on a per-cpu basis when the map 650 * was inited. This function is used by zalloc() to avoid a recursion 651 * when zalloc() itself needs to allocate additional kernel memory. 652 * 653 * This function works like the normal reserve but does not load the 654 * vm_map_entry cache (because that would result in an infinite 655 * recursion). Note that gd_vme_avail may go negative. This is expected. 656 * 657 * Any caller of this function must be sure to renormalize after 658 * potentially eating entries to ensure that the reserve supply 659 * remains intact. 660 * 661 * No requirements. 662 */ 663 int 664 vm_map_entry_kreserve(int count) 665 { 666 struct globaldata *gd = mycpu; 667 668 crit_enter(); 669 gd->gd_vme_avail -= count; 670 crit_exit(); 671 KASSERT(gd->gd_vme_base != NULL, 672 ("no reserved entries left, gd_vme_avail = %d\n", 673 gd->gd_vme_avail)); 674 return(count); 675 } 676 677 /* 678 * Release previously reserved map entries for kernel_map. We do not 679 * attempt to clean up like the normal release function as this would 680 * cause an unnecessary (but probably not fatal) deep procedure call. 681 * 682 * No requirements. 683 */ 684 void 685 vm_map_entry_krelease(int count) 686 { 687 struct globaldata *gd = mycpu; 688 689 crit_enter(); 690 gd->gd_vme_avail += count; 691 crit_exit(); 692 } 693 694 /* 695 * Allocates a VM map entry for insertion. No entry fields are filled in. 696 * 697 * The entries should have previously been reserved. The reservation count 698 * is tracked in (*countp). 699 * 700 * No requirements. 701 */ 702 static vm_map_entry_t 703 vm_map_entry_create(vm_map_t map, int *countp) 704 { 705 struct globaldata *gd = mycpu; 706 vm_map_entry_t entry; 707 708 KKASSERT(*countp > 0); 709 --*countp; 710 crit_enter(); 711 entry = gd->gd_vme_base; 712 KASSERT(entry != NULL, ("gd_vme_base NULL! count %d", *countp)); 713 gd->gd_vme_base = entry->next; 714 crit_exit(); 715 716 return(entry); 717 } 718 719 /* 720 * Dispose of a vm_map_entry that is no longer being referenced. 721 * 722 * No requirements. 723 */ 724 static void 725 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry, int *countp) 726 { 727 struct globaldata *gd = mycpu; 728 729 KKASSERT(map->hint != entry); 730 KKASSERT(map->first_free != entry); 731 732 ++*countp; 733 crit_enter(); 734 entry->next = gd->gd_vme_base; 735 gd->gd_vme_base = entry; 736 crit_exit(); 737 } 738 739 740 /* 741 * Insert/remove entries from maps. 742 * 743 * The related map must be exclusively locked. 744 * No other requirements. 745 * 746 * NOTE! We currently acquire the vmspace_token only to avoid races 747 * against the pageout daemon's calls to vmspace_*_count(), which 748 * are unable to safely lock the vm_map without potentially 749 * deadlocking. 750 */ 751 static __inline void 752 vm_map_entry_link(vm_map_t map, 753 vm_map_entry_t after_where, 754 vm_map_entry_t entry) 755 { 756 ASSERT_VM_MAP_LOCKED(map); 757 758 lwkt_gettoken(&vmspace_token); 759 map->nentries++; 760 entry->prev = after_where; 761 entry->next = after_where->next; 762 entry->next->prev = entry; 763 after_where->next = entry; 764 if (vm_map_rb_tree_RB_INSERT(&map->rb_root, entry)) 765 panic("vm_map_entry_link: dup addr map %p ent %p", map, entry); 766 lwkt_reltoken(&vmspace_token); 767 } 768 769 static __inline void 770 vm_map_entry_unlink(vm_map_t map, 771 vm_map_entry_t entry) 772 { 773 vm_map_entry_t prev; 774 vm_map_entry_t next; 775 776 ASSERT_VM_MAP_LOCKED(map); 777 778 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 779 panic("vm_map_entry_unlink: attempt to mess with " 780 "locked entry! %p", entry); 781 } 782 lwkt_gettoken(&vmspace_token); 783 prev = entry->prev; 784 next = entry->next; 785 next->prev = prev; 786 prev->next = next; 787 vm_map_rb_tree_RB_REMOVE(&map->rb_root, entry); 788 map->nentries--; 789 lwkt_reltoken(&vmspace_token); 790 } 791 792 /* 793 * Finds the map entry containing (or immediately preceding) the specified 794 * address in the given map. The entry is returned in (*entry). 795 * 796 * The boolean result indicates whether the address is actually contained 797 * in the map. 798 * 799 * The related map must be locked. 800 * No other requirements. 801 */ 802 boolean_t 803 vm_map_lookup_entry(vm_map_t map, vm_offset_t address, vm_map_entry_t *entry) 804 { 805 vm_map_entry_t tmp; 806 vm_map_entry_t last; 807 808 ASSERT_VM_MAP_LOCKED(map); 809 #if 0 810 /* 811 * XXX TEMPORARILY DISABLED. For some reason our attempt to revive 812 * the hint code with the red-black lookup meets with system crashes 813 * and lockups. We do not yet know why. 814 * 815 * It is possible that the problem is related to the setting 816 * of the hint during map_entry deletion, in the code specified 817 * at the GGG comment later on in this file. 818 */ 819 /* 820 * Quickly check the cached hint, there's a good chance of a match. 821 */ 822 if (map->hint != &map->header) { 823 tmp = map->hint; 824 if (address >= tmp->start && address < tmp->end) { 825 *entry = tmp; 826 return(TRUE); 827 } 828 } 829 #endif 830 831 /* 832 * Locate the record from the top of the tree. 'last' tracks the 833 * closest prior record and is returned if no match is found, which 834 * in binary tree terms means tracking the most recent right-branch 835 * taken. If there is no prior record, &map->header is returned. 836 */ 837 last = &map->header; 838 tmp = RB_ROOT(&map->rb_root); 839 840 while (tmp) { 841 if (address >= tmp->start) { 842 if (address < tmp->end) { 843 *entry = tmp; 844 map->hint = tmp; 845 return(TRUE); 846 } 847 last = tmp; 848 tmp = RB_RIGHT(tmp, rb_entry); 849 } else { 850 tmp = RB_LEFT(tmp, rb_entry); 851 } 852 } 853 *entry = last; 854 return (FALSE); 855 } 856 857 /* 858 * Inserts the given whole VM object into the target map at the specified 859 * address range. The object's size should match that of the address range. 860 * 861 * The map must be exclusively locked. 862 * The caller must have reserved sufficient vm_map_entry structures. 863 * 864 * If object is non-NULL, ref count must be bumped by caller 865 * prior to making call to account for the new entry. 866 */ 867 int 868 vm_map_insert(vm_map_t map, int *countp, 869 vm_object_t object, vm_ooffset_t offset, 870 vm_offset_t start, vm_offset_t end, 871 vm_maptype_t maptype, 872 vm_prot_t prot, vm_prot_t max, 873 int cow) 874 { 875 vm_map_entry_t new_entry; 876 vm_map_entry_t prev_entry; 877 vm_map_entry_t temp_entry; 878 vm_eflags_t protoeflags; 879 880 ASSERT_VM_MAP_LOCKED(map); 881 882 /* 883 * Check that the start and end points are not bogus. 884 */ 885 if ((start < map->min_offset) || (end > map->max_offset) || 886 (start >= end)) 887 return (KERN_INVALID_ADDRESS); 888 889 /* 890 * Find the entry prior to the proposed starting address; if it's part 891 * of an existing entry, this range is bogus. 892 */ 893 if (vm_map_lookup_entry(map, start, &temp_entry)) 894 return (KERN_NO_SPACE); 895 896 prev_entry = temp_entry; 897 898 /* 899 * Assert that the next entry doesn't overlap the end point. 900 */ 901 902 if ((prev_entry->next != &map->header) && 903 (prev_entry->next->start < end)) 904 return (KERN_NO_SPACE); 905 906 protoeflags = 0; 907 908 if (cow & MAP_COPY_ON_WRITE) 909 protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY; 910 911 if (cow & MAP_NOFAULT) { 912 protoeflags |= MAP_ENTRY_NOFAULT; 913 914 KASSERT(object == NULL, 915 ("vm_map_insert: paradoxical MAP_NOFAULT request")); 916 } 917 if (cow & MAP_DISABLE_SYNCER) 918 protoeflags |= MAP_ENTRY_NOSYNC; 919 if (cow & MAP_DISABLE_COREDUMP) 920 protoeflags |= MAP_ENTRY_NOCOREDUMP; 921 if (cow & MAP_IS_STACK) 922 protoeflags |= MAP_ENTRY_STACK; 923 if (cow & MAP_IS_KSTACK) 924 protoeflags |= MAP_ENTRY_KSTACK; 925 926 lwkt_gettoken(&vm_token); 927 lwkt_gettoken(&vmobj_token); 928 929 if (object) { 930 /* 931 * When object is non-NULL, it could be shared with another 932 * process. We have to set or clear OBJ_ONEMAPPING 933 * appropriately. 934 */ 935 936 if ((object->ref_count > 1) || (object->shadow_count != 0)) { 937 vm_object_clear_flag(object, OBJ_ONEMAPPING); 938 } 939 } 940 else if ((prev_entry != &map->header) && 941 (prev_entry->eflags == protoeflags) && 942 (prev_entry->end == start) && 943 (prev_entry->wired_count == 0) && 944 prev_entry->maptype == maptype && 945 ((prev_entry->object.vm_object == NULL) || 946 vm_object_coalesce(prev_entry->object.vm_object, 947 OFF_TO_IDX(prev_entry->offset), 948 (vm_size_t)(prev_entry->end - prev_entry->start), 949 (vm_size_t)(end - prev_entry->end)))) { 950 /* 951 * We were able to extend the object. Determine if we 952 * can extend the previous map entry to include the 953 * new range as well. 954 */ 955 if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) && 956 (prev_entry->protection == prot) && 957 (prev_entry->max_protection == max)) { 958 lwkt_reltoken(&vmobj_token); 959 lwkt_reltoken(&vm_token); 960 map->size += (end - prev_entry->end); 961 prev_entry->end = end; 962 vm_map_simplify_entry(map, prev_entry, countp); 963 return (KERN_SUCCESS); 964 } 965 966 /* 967 * If we can extend the object but cannot extend the 968 * map entry, we have to create a new map entry. We 969 * must bump the ref count on the extended object to 970 * account for it. object may be NULL. 971 */ 972 object = prev_entry->object.vm_object; 973 offset = prev_entry->offset + 974 (prev_entry->end - prev_entry->start); 975 vm_object_reference_locked(object); 976 } 977 978 lwkt_reltoken(&vmobj_token); 979 lwkt_reltoken(&vm_token); 980 981 /* 982 * NOTE: if conditionals fail, object can be NULL here. This occurs 983 * in things like the buffer map where we manage kva but do not manage 984 * backing objects. 985 */ 986 987 /* 988 * Create a new entry 989 */ 990 991 new_entry = vm_map_entry_create(map, countp); 992 new_entry->start = start; 993 new_entry->end = end; 994 995 new_entry->maptype = maptype; 996 new_entry->eflags = protoeflags; 997 new_entry->object.vm_object = object; 998 new_entry->offset = offset; 999 new_entry->aux.master_pde = 0; 1000 1001 new_entry->inheritance = VM_INHERIT_DEFAULT; 1002 new_entry->protection = prot; 1003 new_entry->max_protection = max; 1004 new_entry->wired_count = 0; 1005 1006 /* 1007 * Insert the new entry into the list 1008 */ 1009 1010 vm_map_entry_link(map, prev_entry, new_entry); 1011 map->size += new_entry->end - new_entry->start; 1012 1013 /* 1014 * Update the free space hint. Entries cannot overlap. 1015 * An exact comparison is needed to avoid matching 1016 * against the map->header. 1017 */ 1018 if ((map->first_free == prev_entry) && 1019 (prev_entry->end == new_entry->start)) { 1020 map->first_free = new_entry; 1021 } 1022 1023 #if 0 1024 /* 1025 * Temporarily removed to avoid MAP_STACK panic, due to 1026 * MAP_STACK being a huge hack. Will be added back in 1027 * when MAP_STACK (and the user stack mapping) is fixed. 1028 */ 1029 /* 1030 * It may be possible to simplify the entry 1031 */ 1032 vm_map_simplify_entry(map, new_entry, countp); 1033 #endif 1034 1035 /* 1036 * Try to pre-populate the page table. Mappings governed by virtual 1037 * page tables cannot be prepopulated without a lot of work, so 1038 * don't try. 1039 */ 1040 if ((cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) && 1041 maptype != VM_MAPTYPE_VPAGETABLE) { 1042 pmap_object_init_pt(map->pmap, start, prot, 1043 object, OFF_TO_IDX(offset), end - start, 1044 cow & MAP_PREFAULT_PARTIAL); 1045 } 1046 1047 return (KERN_SUCCESS); 1048 } 1049 1050 /* 1051 * Find sufficient space for `length' bytes in the given map, starting at 1052 * `start'. Returns 0 on success, 1 on no space. 1053 * 1054 * This function will returned an arbitrarily aligned pointer. If no 1055 * particular alignment is required you should pass align as 1. Note that 1056 * the map may return PAGE_SIZE aligned pointers if all the lengths used in 1057 * the map are a multiple of PAGE_SIZE, even if you pass a smaller align 1058 * argument. 1059 * 1060 * 'align' should be a power of 2 but is not required to be. 1061 * 1062 * The map must be exclusively locked. 1063 * No other requirements. 1064 */ 1065 int 1066 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, 1067 vm_size_t align, int flags, vm_offset_t *addr) 1068 { 1069 vm_map_entry_t entry, next; 1070 vm_offset_t end; 1071 vm_offset_t align_mask; 1072 1073 if (start < map->min_offset) 1074 start = map->min_offset; 1075 if (start > map->max_offset) 1076 return (1); 1077 1078 /* 1079 * If the alignment is not a power of 2 we will have to use 1080 * a mod/division, set align_mask to a special value. 1081 */ 1082 if ((align | (align - 1)) + 1 != (align << 1)) 1083 align_mask = (vm_offset_t)-1; 1084 else 1085 align_mask = align - 1; 1086 1087 /* 1088 * Look for the first possible address; if there's already something 1089 * at this address, we have to start after it. 1090 */ 1091 if (start == map->min_offset) { 1092 if ((entry = map->first_free) != &map->header) 1093 start = entry->end; 1094 } else { 1095 vm_map_entry_t tmp; 1096 1097 if (vm_map_lookup_entry(map, start, &tmp)) 1098 start = tmp->end; 1099 entry = tmp; 1100 } 1101 1102 /* 1103 * Look through the rest of the map, trying to fit a new region in the 1104 * gap between existing regions, or after the very last region. 1105 */ 1106 for (;; start = (entry = next)->end) { 1107 /* 1108 * Adjust the proposed start by the requested alignment, 1109 * be sure that we didn't wrap the address. 1110 */ 1111 if (align_mask == (vm_offset_t)-1) 1112 end = ((start + align - 1) / align) * align; 1113 else 1114 end = (start + align_mask) & ~align_mask; 1115 if (end < start) 1116 return (1); 1117 start = end; 1118 /* 1119 * Find the end of the proposed new region. Be sure we didn't 1120 * go beyond the end of the map, or wrap around the address. 1121 * Then check to see if this is the last entry or if the 1122 * proposed end fits in the gap between this and the next 1123 * entry. 1124 */ 1125 end = start + length; 1126 if (end > map->max_offset || end < start) 1127 return (1); 1128 next = entry->next; 1129 1130 /* 1131 * If the next entry's start address is beyond the desired 1132 * end address we may have found a good entry. 1133 * 1134 * If the next entry is a stack mapping we do not map into 1135 * the stack's reserved space. 1136 * 1137 * XXX continue to allow mapping into the stack's reserved 1138 * space if doing a MAP_STACK mapping inside a MAP_STACK 1139 * mapping, for backwards compatibility. But the caller 1140 * really should use MAP_STACK | MAP_TRYFIXED if they 1141 * want to do that. 1142 */ 1143 if (next == &map->header) 1144 break; 1145 if (next->start >= end) { 1146 if ((next->eflags & MAP_ENTRY_STACK) == 0) 1147 break; 1148 if (flags & MAP_STACK) 1149 break; 1150 if (next->start - next->aux.avail_ssize >= end) 1151 break; 1152 } 1153 } 1154 map->hint = entry; 1155 1156 /* 1157 * Grow the kernel_map if necessary. pmap_growkernel() will panic 1158 * if it fails. The kernel_map is locked and nothing can steal 1159 * our address space if pmap_growkernel() blocks. 1160 * 1161 * NOTE: This may be unconditionally called for kldload areas on 1162 * x86_64 because these do not bump kernel_vm_end (which would 1163 * fill 128G worth of page tables!). Therefore we must not 1164 * retry. 1165 */ 1166 if (map == &kernel_map) { 1167 vm_offset_t kstop; 1168 1169 kstop = round_page(start + length); 1170 if (kstop > kernel_vm_end) 1171 pmap_growkernel(start, kstop); 1172 } 1173 *addr = start; 1174 return (0); 1175 } 1176 1177 /* 1178 * vm_map_find finds an unallocated region in the target address map with 1179 * the given length. The search is defined to be first-fit from the 1180 * specified address; the region found is returned in the same parameter. 1181 * 1182 * If object is non-NULL, ref count must be bumped by caller 1183 * prior to making call to account for the new entry. 1184 * 1185 * No requirements. This function will lock the map temporarily. 1186 */ 1187 int 1188 vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, 1189 vm_offset_t *addr, vm_size_t length, vm_size_t align, 1190 boolean_t fitit, 1191 vm_maptype_t maptype, 1192 vm_prot_t prot, vm_prot_t max, 1193 int cow) 1194 { 1195 vm_offset_t start; 1196 int result; 1197 int count; 1198 1199 start = *addr; 1200 1201 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1202 vm_map_lock(map); 1203 if (fitit) { 1204 if (vm_map_findspace(map, start, length, align, 0, addr)) { 1205 vm_map_unlock(map); 1206 vm_map_entry_release(count); 1207 return (KERN_NO_SPACE); 1208 } 1209 start = *addr; 1210 } 1211 result = vm_map_insert(map, &count, object, offset, 1212 start, start + length, 1213 maptype, 1214 prot, max, 1215 cow); 1216 vm_map_unlock(map); 1217 vm_map_entry_release(count); 1218 1219 return (result); 1220 } 1221 1222 /* 1223 * Simplify the given map entry by merging with either neighbor. This 1224 * routine also has the ability to merge with both neighbors. 1225 * 1226 * This routine guarentees that the passed entry remains valid (though 1227 * possibly extended). When merging, this routine may delete one or 1228 * both neighbors. No action is taken on entries which have their 1229 * in-transition flag set. 1230 * 1231 * The map must be exclusively locked. 1232 */ 1233 void 1234 vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry, int *countp) 1235 { 1236 vm_map_entry_t next, prev; 1237 vm_size_t prevsize, esize; 1238 1239 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1240 ++mycpu->gd_cnt.v_intrans_coll; 1241 return; 1242 } 1243 1244 if (entry->maptype == VM_MAPTYPE_SUBMAP) 1245 return; 1246 1247 prev = entry->prev; 1248 if (prev != &map->header) { 1249 prevsize = prev->end - prev->start; 1250 if ( (prev->end == entry->start) && 1251 (prev->maptype == entry->maptype) && 1252 (prev->object.vm_object == entry->object.vm_object) && 1253 (!prev->object.vm_object || 1254 (prev->offset + prevsize == entry->offset)) && 1255 (prev->eflags == entry->eflags) && 1256 (prev->protection == entry->protection) && 1257 (prev->max_protection == entry->max_protection) && 1258 (prev->inheritance == entry->inheritance) && 1259 (prev->wired_count == entry->wired_count)) { 1260 if (map->first_free == prev) 1261 map->first_free = entry; 1262 if (map->hint == prev) 1263 map->hint = entry; 1264 vm_map_entry_unlink(map, prev); 1265 entry->start = prev->start; 1266 entry->offset = prev->offset; 1267 if (prev->object.vm_object) 1268 vm_object_deallocate(prev->object.vm_object); 1269 vm_map_entry_dispose(map, prev, countp); 1270 } 1271 } 1272 1273 next = entry->next; 1274 if (next != &map->header) { 1275 esize = entry->end - entry->start; 1276 if ((entry->end == next->start) && 1277 (next->maptype == entry->maptype) && 1278 (next->object.vm_object == entry->object.vm_object) && 1279 (!entry->object.vm_object || 1280 (entry->offset + esize == next->offset)) && 1281 (next->eflags == entry->eflags) && 1282 (next->protection == entry->protection) && 1283 (next->max_protection == entry->max_protection) && 1284 (next->inheritance == entry->inheritance) && 1285 (next->wired_count == entry->wired_count)) { 1286 if (map->first_free == next) 1287 map->first_free = entry; 1288 if (map->hint == next) 1289 map->hint = entry; 1290 vm_map_entry_unlink(map, next); 1291 entry->end = next->end; 1292 if (next->object.vm_object) 1293 vm_object_deallocate(next->object.vm_object); 1294 vm_map_entry_dispose(map, next, countp); 1295 } 1296 } 1297 } 1298 1299 /* 1300 * Asserts that the given entry begins at or after the specified address. 1301 * If necessary, it splits the entry into two. 1302 */ 1303 #define vm_map_clip_start(map, entry, startaddr, countp) \ 1304 { \ 1305 if (startaddr > entry->start) \ 1306 _vm_map_clip_start(map, entry, startaddr, countp); \ 1307 } 1308 1309 /* 1310 * This routine is called only when it is known that the entry must be split. 1311 * 1312 * The map must be exclusively locked. 1313 */ 1314 static void 1315 _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start, 1316 int *countp) 1317 { 1318 vm_map_entry_t new_entry; 1319 1320 /* 1321 * Split off the front portion -- note that we must insert the new 1322 * entry BEFORE this one, so that this entry has the specified 1323 * starting address. 1324 */ 1325 1326 vm_map_simplify_entry(map, entry, countp); 1327 1328 /* 1329 * If there is no object backing this entry, we might as well create 1330 * one now. If we defer it, an object can get created after the map 1331 * is clipped, and individual objects will be created for the split-up 1332 * map. This is a bit of a hack, but is also about the best place to 1333 * put this improvement. 1334 */ 1335 if (entry->object.vm_object == NULL && !map->system_map) { 1336 vm_map_entry_allocate_object(entry); 1337 } 1338 1339 new_entry = vm_map_entry_create(map, countp); 1340 *new_entry = *entry; 1341 1342 new_entry->end = start; 1343 entry->offset += (start - entry->start); 1344 entry->start = start; 1345 1346 vm_map_entry_link(map, entry->prev, new_entry); 1347 1348 switch(entry->maptype) { 1349 case VM_MAPTYPE_NORMAL: 1350 case VM_MAPTYPE_VPAGETABLE: 1351 vm_object_reference(new_entry->object.vm_object); 1352 break; 1353 default: 1354 break; 1355 } 1356 } 1357 1358 /* 1359 * Asserts that the given entry ends at or before the specified address. 1360 * If necessary, it splits the entry into two. 1361 * 1362 * The map must be exclusively locked. 1363 */ 1364 #define vm_map_clip_end(map, entry, endaddr, countp) \ 1365 { \ 1366 if (endaddr < entry->end) \ 1367 _vm_map_clip_end(map, entry, endaddr, countp); \ 1368 } 1369 1370 /* 1371 * This routine is called only when it is known that the entry must be split. 1372 * 1373 * The map must be exclusively locked. 1374 */ 1375 static void 1376 _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end, 1377 int *countp) 1378 { 1379 vm_map_entry_t new_entry; 1380 1381 /* 1382 * If there is no object backing this entry, we might as well create 1383 * one now. If we defer it, an object can get created after the map 1384 * is clipped, and individual objects will be created for the split-up 1385 * map. This is a bit of a hack, but is also about the best place to 1386 * put this improvement. 1387 */ 1388 1389 if (entry->object.vm_object == NULL && !map->system_map) { 1390 vm_map_entry_allocate_object(entry); 1391 } 1392 1393 /* 1394 * Create a new entry and insert it AFTER the specified entry 1395 */ 1396 1397 new_entry = vm_map_entry_create(map, countp); 1398 *new_entry = *entry; 1399 1400 new_entry->start = entry->end = end; 1401 new_entry->offset += (end - entry->start); 1402 1403 vm_map_entry_link(map, entry, new_entry); 1404 1405 switch(entry->maptype) { 1406 case VM_MAPTYPE_NORMAL: 1407 case VM_MAPTYPE_VPAGETABLE: 1408 vm_object_reference(new_entry->object.vm_object); 1409 break; 1410 default: 1411 break; 1412 } 1413 } 1414 1415 /* 1416 * Asserts that the starting and ending region addresses fall within the 1417 * valid range for the map. 1418 */ 1419 #define VM_MAP_RANGE_CHECK(map, start, end) \ 1420 { \ 1421 if (start < vm_map_min(map)) \ 1422 start = vm_map_min(map); \ 1423 if (end > vm_map_max(map)) \ 1424 end = vm_map_max(map); \ 1425 if (start > end) \ 1426 start = end; \ 1427 } 1428 1429 /* 1430 * Used to block when an in-transition collison occurs. The map 1431 * is unlocked for the sleep and relocked before the return. 1432 */ 1433 void 1434 vm_map_transition_wait(vm_map_t map) 1435 { 1436 tsleep_interlock(map, 0); 1437 vm_map_unlock(map); 1438 tsleep(map, PINTERLOCKED, "vment", 0); 1439 vm_map_lock(map); 1440 } 1441 1442 /* 1443 * When we do blocking operations with the map lock held it is 1444 * possible that a clip might have occured on our in-transit entry, 1445 * requiring an adjustment to the entry in our loop. These macros 1446 * help the pageable and clip_range code deal with the case. The 1447 * conditional costs virtually nothing if no clipping has occured. 1448 */ 1449 1450 #define CLIP_CHECK_BACK(entry, save_start) \ 1451 do { \ 1452 while (entry->start != save_start) { \ 1453 entry = entry->prev; \ 1454 KASSERT(entry != &map->header, ("bad entry clip")); \ 1455 } \ 1456 } while(0) 1457 1458 #define CLIP_CHECK_FWD(entry, save_end) \ 1459 do { \ 1460 while (entry->end != save_end) { \ 1461 entry = entry->next; \ 1462 KASSERT(entry != &map->header, ("bad entry clip")); \ 1463 } \ 1464 } while(0) 1465 1466 1467 /* 1468 * Clip the specified range and return the base entry. The 1469 * range may cover several entries starting at the returned base 1470 * and the first and last entry in the covering sequence will be 1471 * properly clipped to the requested start and end address. 1472 * 1473 * If no holes are allowed you should pass the MAP_CLIP_NO_HOLES 1474 * flag. 1475 * 1476 * The MAP_ENTRY_IN_TRANSITION flag will be set for the entries 1477 * covered by the requested range. 1478 * 1479 * The map must be exclusively locked on entry and will remain locked 1480 * on return. If no range exists or the range contains holes and you 1481 * specified that no holes were allowed, NULL will be returned. This 1482 * routine may temporarily unlock the map in order avoid a deadlock when 1483 * sleeping. 1484 */ 1485 static 1486 vm_map_entry_t 1487 vm_map_clip_range(vm_map_t map, vm_offset_t start, vm_offset_t end, 1488 int *countp, int flags) 1489 { 1490 vm_map_entry_t start_entry; 1491 vm_map_entry_t entry; 1492 1493 /* 1494 * Locate the entry and effect initial clipping. The in-transition 1495 * case does not occur very often so do not try to optimize it. 1496 */ 1497 again: 1498 if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) 1499 return (NULL); 1500 entry = start_entry; 1501 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1502 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1503 ++mycpu->gd_cnt.v_intrans_coll; 1504 ++mycpu->gd_cnt.v_intrans_wait; 1505 vm_map_transition_wait(map); 1506 /* 1507 * entry and/or start_entry may have been clipped while 1508 * we slept, or may have gone away entirely. We have 1509 * to restart from the lookup. 1510 */ 1511 goto again; 1512 } 1513 1514 /* 1515 * Since we hold an exclusive map lock we do not have to restart 1516 * after clipping, even though clipping may block in zalloc. 1517 */ 1518 vm_map_clip_start(map, entry, start, countp); 1519 vm_map_clip_end(map, entry, end, countp); 1520 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 1521 1522 /* 1523 * Scan entries covered by the range. When working on the next 1524 * entry a restart need only re-loop on the current entry which 1525 * we have already locked, since 'next' may have changed. Also, 1526 * even though entry is safe, it may have been clipped so we 1527 * have to iterate forwards through the clip after sleeping. 1528 */ 1529 while (entry->next != &map->header && entry->next->start < end) { 1530 vm_map_entry_t next = entry->next; 1531 1532 if (flags & MAP_CLIP_NO_HOLES) { 1533 if (next->start > entry->end) { 1534 vm_map_unclip_range(map, start_entry, 1535 start, entry->end, countp, flags); 1536 return(NULL); 1537 } 1538 } 1539 1540 if (next->eflags & MAP_ENTRY_IN_TRANSITION) { 1541 vm_offset_t save_end = entry->end; 1542 next->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1543 ++mycpu->gd_cnt.v_intrans_coll; 1544 ++mycpu->gd_cnt.v_intrans_wait; 1545 vm_map_transition_wait(map); 1546 1547 /* 1548 * clips might have occured while we blocked. 1549 */ 1550 CLIP_CHECK_FWD(entry, save_end); 1551 CLIP_CHECK_BACK(start_entry, start); 1552 continue; 1553 } 1554 /* 1555 * No restart necessary even though clip_end may block, we 1556 * are holding the map lock. 1557 */ 1558 vm_map_clip_end(map, next, end, countp); 1559 next->eflags |= MAP_ENTRY_IN_TRANSITION; 1560 entry = next; 1561 } 1562 if (flags & MAP_CLIP_NO_HOLES) { 1563 if (entry->end != end) { 1564 vm_map_unclip_range(map, start_entry, 1565 start, entry->end, countp, flags); 1566 return(NULL); 1567 } 1568 } 1569 return(start_entry); 1570 } 1571 1572 /* 1573 * Undo the effect of vm_map_clip_range(). You should pass the same 1574 * flags and the same range that you passed to vm_map_clip_range(). 1575 * This code will clear the in-transition flag on the entries and 1576 * wake up anyone waiting. This code will also simplify the sequence 1577 * and attempt to merge it with entries before and after the sequence. 1578 * 1579 * The map must be locked on entry and will remain locked on return. 1580 * 1581 * Note that you should also pass the start_entry returned by 1582 * vm_map_clip_range(). However, if you block between the two calls 1583 * with the map unlocked please be aware that the start_entry may 1584 * have been clipped and you may need to scan it backwards to find 1585 * the entry corresponding with the original start address. You are 1586 * responsible for this, vm_map_unclip_range() expects the correct 1587 * start_entry to be passed to it and will KASSERT otherwise. 1588 */ 1589 static 1590 void 1591 vm_map_unclip_range(vm_map_t map, vm_map_entry_t start_entry, 1592 vm_offset_t start, vm_offset_t end, 1593 int *countp, int flags) 1594 { 1595 vm_map_entry_t entry; 1596 1597 entry = start_entry; 1598 1599 KASSERT(entry->start == start, ("unclip_range: illegal base entry")); 1600 while (entry != &map->header && entry->start < end) { 1601 KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION, 1602 ("in-transition flag not set during unclip on: %p", 1603 entry)); 1604 KASSERT(entry->end <= end, 1605 ("unclip_range: tail wasn't clipped")); 1606 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; 1607 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 1608 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 1609 wakeup(map); 1610 } 1611 entry = entry->next; 1612 } 1613 1614 /* 1615 * Simplification does not block so there is no restart case. 1616 */ 1617 entry = start_entry; 1618 while (entry != &map->header && entry->start < end) { 1619 vm_map_simplify_entry(map, entry, countp); 1620 entry = entry->next; 1621 } 1622 } 1623 1624 /* 1625 * Mark the given range as handled by a subordinate map. 1626 * 1627 * This range must have been created with vm_map_find(), and no other 1628 * operations may have been performed on this range prior to calling 1629 * vm_map_submap(). 1630 * 1631 * Submappings cannot be removed. 1632 * 1633 * No requirements. 1634 */ 1635 int 1636 vm_map_submap(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_map_t submap) 1637 { 1638 vm_map_entry_t entry; 1639 int result = KERN_INVALID_ARGUMENT; 1640 int count; 1641 1642 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1643 vm_map_lock(map); 1644 1645 VM_MAP_RANGE_CHECK(map, start, end); 1646 1647 if (vm_map_lookup_entry(map, start, &entry)) { 1648 vm_map_clip_start(map, entry, start, &count); 1649 } else { 1650 entry = entry->next; 1651 } 1652 1653 vm_map_clip_end(map, entry, end, &count); 1654 1655 if ((entry->start == start) && (entry->end == end) && 1656 ((entry->eflags & MAP_ENTRY_COW) == 0) && 1657 (entry->object.vm_object == NULL)) { 1658 entry->object.sub_map = submap; 1659 entry->maptype = VM_MAPTYPE_SUBMAP; 1660 result = KERN_SUCCESS; 1661 } 1662 vm_map_unlock(map); 1663 vm_map_entry_release(count); 1664 1665 return (result); 1666 } 1667 1668 /* 1669 * Sets the protection of the specified address region in the target map. 1670 * If "set_max" is specified, the maximum protection is to be set; 1671 * otherwise, only the current protection is affected. 1672 * 1673 * The protection is not applicable to submaps, but is applicable to normal 1674 * maps and maps governed by virtual page tables. For example, when operating 1675 * on a virtual page table our protection basically controls how COW occurs 1676 * on the backing object, whereas the virtual page table abstraction itself 1677 * is an abstraction for userland. 1678 * 1679 * No requirements. 1680 */ 1681 int 1682 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, 1683 vm_prot_t new_prot, boolean_t set_max) 1684 { 1685 vm_map_entry_t current; 1686 vm_map_entry_t entry; 1687 int count; 1688 1689 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1690 vm_map_lock(map); 1691 1692 VM_MAP_RANGE_CHECK(map, start, end); 1693 1694 if (vm_map_lookup_entry(map, start, &entry)) { 1695 vm_map_clip_start(map, entry, start, &count); 1696 } else { 1697 entry = entry->next; 1698 } 1699 1700 /* 1701 * Make a first pass to check for protection violations. 1702 */ 1703 current = entry; 1704 while ((current != &map->header) && (current->start < end)) { 1705 if (current->maptype == VM_MAPTYPE_SUBMAP) { 1706 vm_map_unlock(map); 1707 vm_map_entry_release(count); 1708 return (KERN_INVALID_ARGUMENT); 1709 } 1710 if ((new_prot & current->max_protection) != new_prot) { 1711 vm_map_unlock(map); 1712 vm_map_entry_release(count); 1713 return (KERN_PROTECTION_FAILURE); 1714 } 1715 current = current->next; 1716 } 1717 1718 /* 1719 * Go back and fix up protections. [Note that clipping is not 1720 * necessary the second time.] 1721 */ 1722 current = entry; 1723 1724 while ((current != &map->header) && (current->start < end)) { 1725 vm_prot_t old_prot; 1726 1727 vm_map_clip_end(map, current, end, &count); 1728 1729 old_prot = current->protection; 1730 if (set_max) { 1731 current->protection = 1732 (current->max_protection = new_prot) & 1733 old_prot; 1734 } else { 1735 current->protection = new_prot; 1736 } 1737 1738 /* 1739 * Update physical map if necessary. Worry about copy-on-write 1740 * here -- CHECK THIS XXX 1741 */ 1742 1743 if (current->protection != old_prot) { 1744 #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ 1745 VM_PROT_ALL) 1746 1747 pmap_protect(map->pmap, current->start, 1748 current->end, 1749 current->protection & MASK(current)); 1750 #undef MASK 1751 } 1752 1753 vm_map_simplify_entry(map, current, &count); 1754 1755 current = current->next; 1756 } 1757 1758 vm_map_unlock(map); 1759 vm_map_entry_release(count); 1760 return (KERN_SUCCESS); 1761 } 1762 1763 /* 1764 * This routine traverses a processes map handling the madvise 1765 * system call. Advisories are classified as either those effecting 1766 * the vm_map_entry structure, or those effecting the underlying 1767 * objects. 1768 * 1769 * The <value> argument is used for extended madvise calls. 1770 * 1771 * No requirements. 1772 */ 1773 int 1774 vm_map_madvise(vm_map_t map, vm_offset_t start, vm_offset_t end, 1775 int behav, off_t value) 1776 { 1777 vm_map_entry_t current, entry; 1778 int modify_map = 0; 1779 int error = 0; 1780 int count; 1781 1782 /* 1783 * Some madvise calls directly modify the vm_map_entry, in which case 1784 * we need to use an exclusive lock on the map and we need to perform 1785 * various clipping operations. Otherwise we only need a read-lock 1786 * on the map. 1787 */ 1788 1789 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1790 1791 switch(behav) { 1792 case MADV_NORMAL: 1793 case MADV_SEQUENTIAL: 1794 case MADV_RANDOM: 1795 case MADV_NOSYNC: 1796 case MADV_AUTOSYNC: 1797 case MADV_NOCORE: 1798 case MADV_CORE: 1799 case MADV_SETMAP: 1800 case MADV_INVAL: 1801 modify_map = 1; 1802 vm_map_lock(map); 1803 break; 1804 case MADV_WILLNEED: 1805 case MADV_DONTNEED: 1806 case MADV_FREE: 1807 vm_map_lock_read(map); 1808 break; 1809 default: 1810 vm_map_entry_release(count); 1811 return (EINVAL); 1812 } 1813 1814 /* 1815 * Locate starting entry and clip if necessary. 1816 */ 1817 1818 VM_MAP_RANGE_CHECK(map, start, end); 1819 1820 if (vm_map_lookup_entry(map, start, &entry)) { 1821 if (modify_map) 1822 vm_map_clip_start(map, entry, start, &count); 1823 } else { 1824 entry = entry->next; 1825 } 1826 1827 if (modify_map) { 1828 /* 1829 * madvise behaviors that are implemented in the vm_map_entry. 1830 * 1831 * We clip the vm_map_entry so that behavioral changes are 1832 * limited to the specified address range. 1833 */ 1834 for (current = entry; 1835 (current != &map->header) && (current->start < end); 1836 current = current->next 1837 ) { 1838 if (current->maptype == VM_MAPTYPE_SUBMAP) 1839 continue; 1840 1841 vm_map_clip_end(map, current, end, &count); 1842 1843 switch (behav) { 1844 case MADV_NORMAL: 1845 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); 1846 break; 1847 case MADV_SEQUENTIAL: 1848 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); 1849 break; 1850 case MADV_RANDOM: 1851 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); 1852 break; 1853 case MADV_NOSYNC: 1854 current->eflags |= MAP_ENTRY_NOSYNC; 1855 break; 1856 case MADV_AUTOSYNC: 1857 current->eflags &= ~MAP_ENTRY_NOSYNC; 1858 break; 1859 case MADV_NOCORE: 1860 current->eflags |= MAP_ENTRY_NOCOREDUMP; 1861 break; 1862 case MADV_CORE: 1863 current->eflags &= ~MAP_ENTRY_NOCOREDUMP; 1864 break; 1865 case MADV_INVAL: 1866 /* 1867 * Invalidate the related pmap entries, used 1868 * to flush portions of the real kernel's 1869 * pmap when the caller has removed or 1870 * modified existing mappings in a virtual 1871 * page table. 1872 */ 1873 pmap_remove(map->pmap, 1874 current->start, current->end); 1875 break; 1876 case MADV_SETMAP: 1877 /* 1878 * Set the page directory page for a map 1879 * governed by a virtual page table. Mark 1880 * the entry as being governed by a virtual 1881 * page table if it is not. 1882 * 1883 * XXX the page directory page is stored 1884 * in the avail_ssize field if the map_entry. 1885 * 1886 * XXX the map simplification code does not 1887 * compare this field so weird things may 1888 * happen if you do not apply this function 1889 * to the entire mapping governed by the 1890 * virtual page table. 1891 */ 1892 if (current->maptype != VM_MAPTYPE_VPAGETABLE) { 1893 error = EINVAL; 1894 break; 1895 } 1896 current->aux.master_pde = value; 1897 pmap_remove(map->pmap, 1898 current->start, current->end); 1899 break; 1900 default: 1901 error = EINVAL; 1902 break; 1903 } 1904 vm_map_simplify_entry(map, current, &count); 1905 } 1906 vm_map_unlock(map); 1907 } else { 1908 vm_pindex_t pindex; 1909 int count; 1910 1911 /* 1912 * madvise behaviors that are implemented in the underlying 1913 * vm_object. 1914 * 1915 * Since we don't clip the vm_map_entry, we have to clip 1916 * the vm_object pindex and count. 1917 * 1918 * NOTE! We currently do not support these functions on 1919 * virtual page tables. 1920 */ 1921 for (current = entry; 1922 (current != &map->header) && (current->start < end); 1923 current = current->next 1924 ) { 1925 vm_offset_t useStart; 1926 1927 if (current->maptype != VM_MAPTYPE_NORMAL) 1928 continue; 1929 1930 pindex = OFF_TO_IDX(current->offset); 1931 count = atop(current->end - current->start); 1932 useStart = current->start; 1933 1934 if (current->start < start) { 1935 pindex += atop(start - current->start); 1936 count -= atop(start - current->start); 1937 useStart = start; 1938 } 1939 if (current->end > end) 1940 count -= atop(current->end - end); 1941 1942 if (count <= 0) 1943 continue; 1944 1945 vm_object_madvise(current->object.vm_object, 1946 pindex, count, behav); 1947 1948 /* 1949 * Try to populate the page table. Mappings governed 1950 * by virtual page tables cannot be pre-populated 1951 * without a lot of work so don't try. 1952 */ 1953 if (behav == MADV_WILLNEED && 1954 current->maptype != VM_MAPTYPE_VPAGETABLE) { 1955 pmap_object_init_pt( 1956 map->pmap, 1957 useStart, 1958 current->protection, 1959 current->object.vm_object, 1960 pindex, 1961 (count << PAGE_SHIFT), 1962 MAP_PREFAULT_MADVISE 1963 ); 1964 } 1965 } 1966 vm_map_unlock_read(map); 1967 } 1968 vm_map_entry_release(count); 1969 return(error); 1970 } 1971 1972 1973 /* 1974 * Sets the inheritance of the specified address range in the target map. 1975 * Inheritance affects how the map will be shared with child maps at the 1976 * time of vm_map_fork. 1977 */ 1978 int 1979 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, 1980 vm_inherit_t new_inheritance) 1981 { 1982 vm_map_entry_t entry; 1983 vm_map_entry_t temp_entry; 1984 int count; 1985 1986 switch (new_inheritance) { 1987 case VM_INHERIT_NONE: 1988 case VM_INHERIT_COPY: 1989 case VM_INHERIT_SHARE: 1990 break; 1991 default: 1992 return (KERN_INVALID_ARGUMENT); 1993 } 1994 1995 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1996 vm_map_lock(map); 1997 1998 VM_MAP_RANGE_CHECK(map, start, end); 1999 2000 if (vm_map_lookup_entry(map, start, &temp_entry)) { 2001 entry = temp_entry; 2002 vm_map_clip_start(map, entry, start, &count); 2003 } else 2004 entry = temp_entry->next; 2005 2006 while ((entry != &map->header) && (entry->start < end)) { 2007 vm_map_clip_end(map, entry, end, &count); 2008 2009 entry->inheritance = new_inheritance; 2010 2011 vm_map_simplify_entry(map, entry, &count); 2012 2013 entry = entry->next; 2014 } 2015 vm_map_unlock(map); 2016 vm_map_entry_release(count); 2017 return (KERN_SUCCESS); 2018 } 2019 2020 /* 2021 * Implement the semantics of mlock 2022 */ 2023 int 2024 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, 2025 boolean_t new_pageable) 2026 { 2027 vm_map_entry_t entry; 2028 vm_map_entry_t start_entry; 2029 vm_offset_t end; 2030 int rv = KERN_SUCCESS; 2031 int count; 2032 2033 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2034 vm_map_lock(map); 2035 VM_MAP_RANGE_CHECK(map, start, real_end); 2036 end = real_end; 2037 2038 start_entry = vm_map_clip_range(map, start, end, &count, 2039 MAP_CLIP_NO_HOLES); 2040 if (start_entry == NULL) { 2041 vm_map_unlock(map); 2042 vm_map_entry_release(count); 2043 return (KERN_INVALID_ADDRESS); 2044 } 2045 2046 if (new_pageable == 0) { 2047 entry = start_entry; 2048 while ((entry != &map->header) && (entry->start < end)) { 2049 vm_offset_t save_start; 2050 vm_offset_t save_end; 2051 2052 /* 2053 * Already user wired or hard wired (trivial cases) 2054 */ 2055 if (entry->eflags & MAP_ENTRY_USER_WIRED) { 2056 entry = entry->next; 2057 continue; 2058 } 2059 if (entry->wired_count != 0) { 2060 entry->wired_count++; 2061 entry->eflags |= MAP_ENTRY_USER_WIRED; 2062 entry = entry->next; 2063 continue; 2064 } 2065 2066 /* 2067 * A new wiring requires instantiation of appropriate 2068 * management structures and the faulting in of the 2069 * page. 2070 */ 2071 if (entry->maptype != VM_MAPTYPE_SUBMAP) { 2072 int copyflag = entry->eflags & 2073 MAP_ENTRY_NEEDS_COPY; 2074 if (copyflag && ((entry->protection & 2075 VM_PROT_WRITE) != 0)) { 2076 vm_map_entry_shadow(entry); 2077 } else if (entry->object.vm_object == NULL && 2078 !map->system_map) { 2079 vm_map_entry_allocate_object(entry); 2080 } 2081 } 2082 entry->wired_count++; 2083 entry->eflags |= MAP_ENTRY_USER_WIRED; 2084 2085 /* 2086 * Now fault in the area. Note that vm_fault_wire() 2087 * may release the map lock temporarily, it will be 2088 * relocked on return. The in-transition 2089 * flag protects the entries. 2090 */ 2091 save_start = entry->start; 2092 save_end = entry->end; 2093 rv = vm_fault_wire(map, entry, TRUE); 2094 if (rv) { 2095 CLIP_CHECK_BACK(entry, save_start); 2096 for (;;) { 2097 KASSERT(entry->wired_count == 1, ("bad wired_count on entry")); 2098 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2099 entry->wired_count = 0; 2100 if (entry->end == save_end) 2101 break; 2102 entry = entry->next; 2103 KASSERT(entry != &map->header, ("bad entry clip during backout")); 2104 } 2105 end = save_start; /* unwire the rest */ 2106 break; 2107 } 2108 /* 2109 * note that even though the entry might have been 2110 * clipped, the USER_WIRED flag we set prevents 2111 * duplication so we do not have to do a 2112 * clip check. 2113 */ 2114 entry = entry->next; 2115 } 2116 2117 /* 2118 * If we failed fall through to the unwiring section to 2119 * unwire what we had wired so far. 'end' has already 2120 * been adjusted. 2121 */ 2122 if (rv) 2123 new_pageable = 1; 2124 2125 /* 2126 * start_entry might have been clipped if we unlocked the 2127 * map and blocked. No matter how clipped it has gotten 2128 * there should be a fragment that is on our start boundary. 2129 */ 2130 CLIP_CHECK_BACK(start_entry, start); 2131 } 2132 2133 /* 2134 * Deal with the unwiring case. 2135 */ 2136 if (new_pageable) { 2137 /* 2138 * This is the unwiring case. We must first ensure that the 2139 * range to be unwired is really wired down. We know there 2140 * are no holes. 2141 */ 2142 entry = start_entry; 2143 while ((entry != &map->header) && (entry->start < end)) { 2144 if ((entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 2145 rv = KERN_INVALID_ARGUMENT; 2146 goto done; 2147 } 2148 KASSERT(entry->wired_count != 0, ("wired count was 0 with USER_WIRED set! %p", entry)); 2149 entry = entry->next; 2150 } 2151 2152 /* 2153 * Now decrement the wiring count for each region. If a region 2154 * becomes completely unwired, unwire its physical pages and 2155 * mappings. 2156 */ 2157 /* 2158 * The map entries are processed in a loop, checking to 2159 * make sure the entry is wired and asserting it has a wired 2160 * count. However, another loop was inserted more-or-less in 2161 * the middle of the unwiring path. This loop picks up the 2162 * "entry" loop variable from the first loop without first 2163 * setting it to start_entry. Naturally, the secound loop 2164 * is never entered and the pages backing the entries are 2165 * never unwired. This can lead to a leak of wired pages. 2166 */ 2167 entry = start_entry; 2168 while ((entry != &map->header) && (entry->start < end)) { 2169 KASSERT(entry->eflags & MAP_ENTRY_USER_WIRED, 2170 ("expected USER_WIRED on entry %p", entry)); 2171 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2172 entry->wired_count--; 2173 if (entry->wired_count == 0) 2174 vm_fault_unwire(map, entry); 2175 entry = entry->next; 2176 } 2177 } 2178 done: 2179 vm_map_unclip_range(map, start_entry, start, real_end, &count, 2180 MAP_CLIP_NO_HOLES); 2181 map->timestamp++; 2182 vm_map_unlock(map); 2183 vm_map_entry_release(count); 2184 return (rv); 2185 } 2186 2187 /* 2188 * Sets the pageability of the specified address range in the target map. 2189 * Regions specified as not pageable require locked-down physical 2190 * memory and physical page maps. 2191 * 2192 * The map must not be locked, but a reference must remain to the map 2193 * throughout the call. 2194 * 2195 * This function may be called via the zalloc path and must properly 2196 * reserve map entries for kernel_map. 2197 * 2198 * No requirements. 2199 */ 2200 int 2201 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, int kmflags) 2202 { 2203 vm_map_entry_t entry; 2204 vm_map_entry_t start_entry; 2205 vm_offset_t end; 2206 int rv = KERN_SUCCESS; 2207 int count; 2208 2209 if (kmflags & KM_KRESERVE) 2210 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); 2211 else 2212 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2213 vm_map_lock(map); 2214 VM_MAP_RANGE_CHECK(map, start, real_end); 2215 end = real_end; 2216 2217 start_entry = vm_map_clip_range(map, start, end, &count, 2218 MAP_CLIP_NO_HOLES); 2219 if (start_entry == NULL) { 2220 vm_map_unlock(map); 2221 rv = KERN_INVALID_ADDRESS; 2222 goto failure; 2223 } 2224 if ((kmflags & KM_PAGEABLE) == 0) { 2225 /* 2226 * Wiring. 2227 * 2228 * 1. Holding the write lock, we create any shadow or zero-fill 2229 * objects that need to be created. Then we clip each map 2230 * entry to the region to be wired and increment its wiring 2231 * count. We create objects before clipping the map entries 2232 * to avoid object proliferation. 2233 * 2234 * 2. We downgrade to a read lock, and call vm_fault_wire to 2235 * fault in the pages for any newly wired area (wired_count is 2236 * 1). 2237 * 2238 * Downgrading to a read lock for vm_fault_wire avoids a 2239 * possible deadlock with another process that may have faulted 2240 * on one of the pages to be wired (it would mark the page busy, 2241 * blocking us, then in turn block on the map lock that we 2242 * hold). Because of problems in the recursive lock package, 2243 * we cannot upgrade to a write lock in vm_map_lookup. Thus, 2244 * any actions that require the write lock must be done 2245 * beforehand. Because we keep the read lock on the map, the 2246 * copy-on-write status of the entries we modify here cannot 2247 * change. 2248 */ 2249 entry = start_entry; 2250 while ((entry != &map->header) && (entry->start < end)) { 2251 /* 2252 * Trivial case if the entry is already wired 2253 */ 2254 if (entry->wired_count) { 2255 entry->wired_count++; 2256 entry = entry->next; 2257 continue; 2258 } 2259 2260 /* 2261 * The entry is being newly wired, we have to setup 2262 * appropriate management structures. A shadow 2263 * object is required for a copy-on-write region, 2264 * or a normal object for a zero-fill region. We 2265 * do not have to do this for entries that point to sub 2266 * maps because we won't hold the lock on the sub map. 2267 */ 2268 if (entry->maptype != VM_MAPTYPE_SUBMAP) { 2269 int copyflag = entry->eflags & 2270 MAP_ENTRY_NEEDS_COPY; 2271 if (copyflag && ((entry->protection & 2272 VM_PROT_WRITE) != 0)) { 2273 vm_map_entry_shadow(entry); 2274 } else if (entry->object.vm_object == NULL && 2275 !map->system_map) { 2276 vm_map_entry_allocate_object(entry); 2277 } 2278 } 2279 2280 entry->wired_count++; 2281 entry = entry->next; 2282 } 2283 2284 /* 2285 * Pass 2. 2286 */ 2287 2288 /* 2289 * HACK HACK HACK HACK 2290 * 2291 * vm_fault_wire() temporarily unlocks the map to avoid 2292 * deadlocks. The in-transition flag from vm_map_clip_range 2293 * call should protect us from changes while the map is 2294 * unlocked. T 2295 * 2296 * NOTE: Previously this comment stated that clipping might 2297 * still occur while the entry is unlocked, but from 2298 * what I can tell it actually cannot. 2299 * 2300 * It is unclear whether the CLIP_CHECK_*() calls 2301 * are still needed but we keep them in anyway. 2302 * 2303 * HACK HACK HACK HACK 2304 */ 2305 2306 entry = start_entry; 2307 while (entry != &map->header && entry->start < end) { 2308 /* 2309 * If vm_fault_wire fails for any page we need to undo 2310 * what has been done. We decrement the wiring count 2311 * for those pages which have not yet been wired (now) 2312 * and unwire those that have (later). 2313 */ 2314 vm_offset_t save_start = entry->start; 2315 vm_offset_t save_end = entry->end; 2316 2317 if (entry->wired_count == 1) 2318 rv = vm_fault_wire(map, entry, FALSE); 2319 if (rv) { 2320 CLIP_CHECK_BACK(entry, save_start); 2321 for (;;) { 2322 KASSERT(entry->wired_count == 1, ("wired_count changed unexpectedly")); 2323 entry->wired_count = 0; 2324 if (entry->end == save_end) 2325 break; 2326 entry = entry->next; 2327 KASSERT(entry != &map->header, ("bad entry clip during backout")); 2328 } 2329 end = save_start; 2330 break; 2331 } 2332 CLIP_CHECK_FWD(entry, save_end); 2333 entry = entry->next; 2334 } 2335 2336 /* 2337 * If a failure occured undo everything by falling through 2338 * to the unwiring code. 'end' has already been adjusted 2339 * appropriately. 2340 */ 2341 if (rv) 2342 kmflags |= KM_PAGEABLE; 2343 2344 /* 2345 * start_entry is still IN_TRANSITION but may have been 2346 * clipped since vm_fault_wire() unlocks and relocks the 2347 * map. No matter how clipped it has gotten there should 2348 * be a fragment that is on our start boundary. 2349 */ 2350 CLIP_CHECK_BACK(start_entry, start); 2351 } 2352 2353 if (kmflags & KM_PAGEABLE) { 2354 /* 2355 * This is the unwiring case. We must first ensure that the 2356 * range to be unwired is really wired down. We know there 2357 * are no holes. 2358 */ 2359 entry = start_entry; 2360 while ((entry != &map->header) && (entry->start < end)) { 2361 if (entry->wired_count == 0) { 2362 rv = KERN_INVALID_ARGUMENT; 2363 goto done; 2364 } 2365 entry = entry->next; 2366 } 2367 2368 /* 2369 * Now decrement the wiring count for each region. If a region 2370 * becomes completely unwired, unwire its physical pages and 2371 * mappings. 2372 */ 2373 entry = start_entry; 2374 while ((entry != &map->header) && (entry->start < end)) { 2375 entry->wired_count--; 2376 if (entry->wired_count == 0) 2377 vm_fault_unwire(map, entry); 2378 entry = entry->next; 2379 } 2380 } 2381 done: 2382 vm_map_unclip_range(map, start_entry, start, real_end, 2383 &count, MAP_CLIP_NO_HOLES); 2384 map->timestamp++; 2385 vm_map_unlock(map); 2386 failure: 2387 if (kmflags & KM_KRESERVE) 2388 vm_map_entry_krelease(count); 2389 else 2390 vm_map_entry_release(count); 2391 return (rv); 2392 } 2393 2394 /* 2395 * Mark a newly allocated address range as wired but do not fault in 2396 * the pages. The caller is expected to load the pages into the object. 2397 * 2398 * The map must be locked on entry and will remain locked on return. 2399 * No other requirements. 2400 */ 2401 void 2402 vm_map_set_wired_quick(vm_map_t map, vm_offset_t addr, vm_size_t size, 2403 int *countp) 2404 { 2405 vm_map_entry_t scan; 2406 vm_map_entry_t entry; 2407 2408 entry = vm_map_clip_range(map, addr, addr + size, 2409 countp, MAP_CLIP_NO_HOLES); 2410 for (scan = entry; 2411 scan != &map->header && scan->start < addr + size; 2412 scan = scan->next) { 2413 KKASSERT(entry->wired_count == 0); 2414 entry->wired_count = 1; 2415 } 2416 vm_map_unclip_range(map, entry, addr, addr + size, 2417 countp, MAP_CLIP_NO_HOLES); 2418 } 2419 2420 /* 2421 * Push any dirty cached pages in the address range to their pager. 2422 * If syncio is TRUE, dirty pages are written synchronously. 2423 * If invalidate is TRUE, any cached pages are freed as well. 2424 * 2425 * This routine is called by sys_msync() 2426 * 2427 * Returns an error if any part of the specified range is not mapped. 2428 * 2429 * No requirements. 2430 */ 2431 int 2432 vm_map_clean(vm_map_t map, vm_offset_t start, vm_offset_t end, 2433 boolean_t syncio, boolean_t invalidate) 2434 { 2435 vm_map_entry_t current; 2436 vm_map_entry_t entry; 2437 vm_size_t size; 2438 vm_object_t object; 2439 vm_ooffset_t offset; 2440 2441 vm_map_lock_read(map); 2442 VM_MAP_RANGE_CHECK(map, start, end); 2443 if (!vm_map_lookup_entry(map, start, &entry)) { 2444 vm_map_unlock_read(map); 2445 return (KERN_INVALID_ADDRESS); 2446 } 2447 /* 2448 * Make a first pass to check for holes. 2449 */ 2450 for (current = entry; current->start < end; current = current->next) { 2451 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2452 vm_map_unlock_read(map); 2453 return (KERN_INVALID_ARGUMENT); 2454 } 2455 if (end > current->end && 2456 (current->next == &map->header || 2457 current->end != current->next->start)) { 2458 vm_map_unlock_read(map); 2459 return (KERN_INVALID_ADDRESS); 2460 } 2461 } 2462 2463 if (invalidate) 2464 pmap_remove(vm_map_pmap(map), start, end); 2465 2466 /* 2467 * Make a second pass, cleaning/uncaching pages from the indicated 2468 * objects as we go. 2469 * 2470 * Hold vm_token to avoid blocking in vm_object_reference() 2471 */ 2472 lwkt_gettoken(&vm_token); 2473 lwkt_gettoken(&vmobj_token); 2474 2475 for (current = entry; current->start < end; current = current->next) { 2476 offset = current->offset + (start - current->start); 2477 size = (end <= current->end ? end : current->end) - start; 2478 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2479 vm_map_t smap; 2480 vm_map_entry_t tentry; 2481 vm_size_t tsize; 2482 2483 smap = current->object.sub_map; 2484 vm_map_lock_read(smap); 2485 vm_map_lookup_entry(smap, offset, &tentry); 2486 tsize = tentry->end - offset; 2487 if (tsize < size) 2488 size = tsize; 2489 object = tentry->object.vm_object; 2490 offset = tentry->offset + (offset - tentry->start); 2491 vm_map_unlock_read(smap); 2492 } else { 2493 object = current->object.vm_object; 2494 } 2495 /* 2496 * Note that there is absolutely no sense in writing out 2497 * anonymous objects, so we track down the vnode object 2498 * to write out. 2499 * We invalidate (remove) all pages from the address space 2500 * anyway, for semantic correctness. 2501 * 2502 * note: certain anonymous maps, such as MAP_NOSYNC maps, 2503 * may start out with a NULL object. 2504 */ 2505 while (object && object->backing_object) { 2506 offset += object->backing_object_offset; 2507 object = object->backing_object; 2508 if (object->size < OFF_TO_IDX( offset + size)) 2509 size = IDX_TO_OFF(object->size) - offset; 2510 } 2511 if (object && (object->type == OBJT_VNODE) && 2512 (current->protection & VM_PROT_WRITE) && 2513 (object->flags & OBJ_NOMSYNC) == 0) { 2514 /* 2515 * Flush pages if writing is allowed, invalidate them 2516 * if invalidation requested. Pages undergoing I/O 2517 * will be ignored by vm_object_page_remove(). 2518 * 2519 * We cannot lock the vnode and then wait for paging 2520 * to complete without deadlocking against vm_fault. 2521 * Instead we simply call vm_object_page_remove() and 2522 * allow it to block internally on a page-by-page 2523 * basis when it encounters pages undergoing async 2524 * I/O. 2525 */ 2526 int flags; 2527 2528 vm_object_reference_locked(object); 2529 vn_lock(object->handle, LK_EXCLUSIVE | LK_RETRY); 2530 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 2531 flags |= invalidate ? OBJPC_INVAL : 0; 2532 2533 /* 2534 * When operating on a virtual page table just 2535 * flush the whole object. XXX we probably ought 2536 * to 2537 */ 2538 switch(current->maptype) { 2539 case VM_MAPTYPE_NORMAL: 2540 vm_object_page_clean(object, 2541 OFF_TO_IDX(offset), 2542 OFF_TO_IDX(offset + size + PAGE_MASK), 2543 flags); 2544 break; 2545 case VM_MAPTYPE_VPAGETABLE: 2546 vm_object_page_clean(object, 0, 0, flags); 2547 break; 2548 } 2549 vn_unlock(((struct vnode *)object->handle)); 2550 vm_object_deallocate_locked(object); 2551 } 2552 if (object && invalidate && 2553 ((object->type == OBJT_VNODE) || 2554 (object->type == OBJT_DEVICE))) { 2555 int clean_only = 2556 (object->type == OBJT_DEVICE) ? FALSE : TRUE; 2557 vm_object_reference_locked(object); 2558 switch(current->maptype) { 2559 case VM_MAPTYPE_NORMAL: 2560 vm_object_page_remove(object, 2561 OFF_TO_IDX(offset), 2562 OFF_TO_IDX(offset + size + PAGE_MASK), 2563 clean_only); 2564 break; 2565 case VM_MAPTYPE_VPAGETABLE: 2566 vm_object_page_remove(object, 0, 0, clean_only); 2567 break; 2568 } 2569 vm_object_deallocate_locked(object); 2570 } 2571 start += size; 2572 } 2573 2574 lwkt_reltoken(&vmobj_token); 2575 lwkt_reltoken(&vm_token); 2576 vm_map_unlock_read(map); 2577 2578 return (KERN_SUCCESS); 2579 } 2580 2581 /* 2582 * Make the region specified by this entry pageable. 2583 * 2584 * The vm_map must be exclusively locked. 2585 */ 2586 static void 2587 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) 2588 { 2589 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2590 entry->wired_count = 0; 2591 vm_fault_unwire(map, entry); 2592 } 2593 2594 /* 2595 * Deallocate the given entry from the target map. 2596 * 2597 * The vm_map must be exclusively locked. 2598 */ 2599 static void 2600 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry, int *countp) 2601 { 2602 vm_map_entry_unlink(map, entry); 2603 map->size -= entry->end - entry->start; 2604 2605 switch(entry->maptype) { 2606 case VM_MAPTYPE_NORMAL: 2607 case VM_MAPTYPE_VPAGETABLE: 2608 vm_object_deallocate(entry->object.vm_object); 2609 break; 2610 default: 2611 break; 2612 } 2613 2614 vm_map_entry_dispose(map, entry, countp); 2615 } 2616 2617 /* 2618 * Deallocates the given address range from the target map. 2619 * 2620 * The vm_map must be exclusively locked. 2621 */ 2622 int 2623 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end, int *countp) 2624 { 2625 vm_object_t object; 2626 vm_map_entry_t entry; 2627 vm_map_entry_t first_entry; 2628 2629 ASSERT_VM_MAP_LOCKED(map); 2630 again: 2631 /* 2632 * Find the start of the region, and clip it. Set entry to point 2633 * at the first record containing the requested address or, if no 2634 * such record exists, the next record with a greater address. The 2635 * loop will run from this point until a record beyond the termination 2636 * address is encountered. 2637 * 2638 * map->hint must be adjusted to not point to anything we delete, 2639 * so set it to the entry prior to the one being deleted. 2640 * 2641 * GGG see other GGG comment. 2642 */ 2643 if (vm_map_lookup_entry(map, start, &first_entry)) { 2644 entry = first_entry; 2645 vm_map_clip_start(map, entry, start, countp); 2646 map->hint = entry->prev; /* possible problem XXX */ 2647 } else { 2648 map->hint = first_entry; /* possible problem XXX */ 2649 entry = first_entry->next; 2650 } 2651 2652 /* 2653 * If a hole opens up prior to the current first_free then 2654 * adjust first_free. As with map->hint, map->first_free 2655 * cannot be left set to anything we might delete. 2656 */ 2657 if (entry == &map->header) { 2658 map->first_free = &map->header; 2659 } else if (map->first_free->start >= start) { 2660 map->first_free = entry->prev; 2661 } 2662 2663 /* 2664 * Step through all entries in this region 2665 */ 2666 while ((entry != &map->header) && (entry->start < end)) { 2667 vm_map_entry_t next; 2668 vm_offset_t s, e; 2669 vm_pindex_t offidxstart, offidxend, count; 2670 2671 /* 2672 * If we hit an in-transition entry we have to sleep and 2673 * retry. It's easier (and not really slower) to just retry 2674 * since this case occurs so rarely and the hint is already 2675 * pointing at the right place. We have to reset the 2676 * start offset so as not to accidently delete an entry 2677 * another process just created in vacated space. 2678 */ 2679 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 2680 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 2681 start = entry->start; 2682 ++mycpu->gd_cnt.v_intrans_coll; 2683 ++mycpu->gd_cnt.v_intrans_wait; 2684 vm_map_transition_wait(map); 2685 goto again; 2686 } 2687 vm_map_clip_end(map, entry, end, countp); 2688 2689 s = entry->start; 2690 e = entry->end; 2691 next = entry->next; 2692 2693 offidxstart = OFF_TO_IDX(entry->offset); 2694 count = OFF_TO_IDX(e - s); 2695 object = entry->object.vm_object; 2696 2697 /* 2698 * Unwire before removing addresses from the pmap; otherwise, 2699 * unwiring will put the entries back in the pmap. 2700 */ 2701 if (entry->wired_count != 0) 2702 vm_map_entry_unwire(map, entry); 2703 2704 offidxend = offidxstart + count; 2705 2706 /* 2707 * Hold vm_token when manipulating vm_objects, 2708 * 2709 * Hold vmobj_token when potentially adding or removing 2710 * objects (collapse requires both). 2711 */ 2712 lwkt_gettoken(&vm_token); 2713 lwkt_gettoken(&vmobj_token); 2714 vm_object_hold(object); 2715 2716 if (object == &kernel_object) { 2717 vm_object_page_remove(object, offidxstart, 2718 offidxend, FALSE); 2719 } else { 2720 pmap_remove(map->pmap, s, e); 2721 2722 if (object != NULL && 2723 object->ref_count != 1 && 2724 (object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == 2725 OBJ_ONEMAPPING && 2726 (object->type == OBJT_DEFAULT || 2727 object->type == OBJT_SWAP)) { 2728 vm_object_collapse(object); 2729 vm_object_page_remove(object, offidxstart, 2730 offidxend, FALSE); 2731 if (object->type == OBJT_SWAP) { 2732 swap_pager_freespace(object, 2733 offidxstart, 2734 count); 2735 } 2736 if (offidxend >= object->size && 2737 offidxstart < object->size) { 2738 object->size = offidxstart; 2739 } 2740 } 2741 } 2742 2743 vm_object_drop(object); 2744 lwkt_reltoken(&vmobj_token); 2745 lwkt_reltoken(&vm_token); 2746 2747 /* 2748 * Delete the entry (which may delete the object) only after 2749 * removing all pmap entries pointing to its pages. 2750 * (Otherwise, its page frames may be reallocated, and any 2751 * modify bits will be set in the wrong object!) 2752 */ 2753 vm_map_entry_delete(map, entry, countp); 2754 entry = next; 2755 } 2756 return (KERN_SUCCESS); 2757 } 2758 2759 /* 2760 * Remove the given address range from the target map. 2761 * This is the exported form of vm_map_delete. 2762 * 2763 * No requirements. 2764 */ 2765 int 2766 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) 2767 { 2768 int result; 2769 int count; 2770 2771 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2772 vm_map_lock(map); 2773 VM_MAP_RANGE_CHECK(map, start, end); 2774 result = vm_map_delete(map, start, end, &count); 2775 vm_map_unlock(map); 2776 vm_map_entry_release(count); 2777 2778 return (result); 2779 } 2780 2781 /* 2782 * Assert that the target map allows the specified privilege on the 2783 * entire address region given. The entire region must be allocated. 2784 * 2785 * The caller must specify whether the vm_map is already locked or not. 2786 */ 2787 boolean_t 2788 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, 2789 vm_prot_t protection, boolean_t have_lock) 2790 { 2791 vm_map_entry_t entry; 2792 vm_map_entry_t tmp_entry; 2793 boolean_t result; 2794 2795 if (have_lock == FALSE) 2796 vm_map_lock_read(map); 2797 2798 if (!vm_map_lookup_entry(map, start, &tmp_entry)) { 2799 if (have_lock == FALSE) 2800 vm_map_unlock_read(map); 2801 return (FALSE); 2802 } 2803 entry = tmp_entry; 2804 2805 result = TRUE; 2806 while (start < end) { 2807 if (entry == &map->header) { 2808 result = FALSE; 2809 break; 2810 } 2811 /* 2812 * No holes allowed! 2813 */ 2814 2815 if (start < entry->start) { 2816 result = FALSE; 2817 break; 2818 } 2819 /* 2820 * Check protection associated with entry. 2821 */ 2822 2823 if ((entry->protection & protection) != protection) { 2824 result = FALSE; 2825 break; 2826 } 2827 /* go to next entry */ 2828 2829 start = entry->end; 2830 entry = entry->next; 2831 } 2832 if (have_lock == FALSE) 2833 vm_map_unlock_read(map); 2834 return (result); 2835 } 2836 2837 /* 2838 * Split the pages in a map entry into a new object. This affords 2839 * easier removal of unused pages, and keeps object inheritance from 2840 * being a negative impact on memory usage. 2841 * 2842 * The vm_map must be exclusively locked. 2843 * The orig_object should be held. 2844 */ 2845 static void 2846 vm_map_split(vm_map_entry_t entry) 2847 { 2848 vm_page_t m; 2849 vm_object_t orig_object, new_object, source; 2850 vm_offset_t s, e; 2851 vm_pindex_t offidxstart, offidxend, idx; 2852 vm_size_t size; 2853 vm_ooffset_t offset; 2854 2855 orig_object = entry->object.vm_object; 2856 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) 2857 return; 2858 if (orig_object->ref_count <= 1) 2859 return; 2860 2861 offset = entry->offset; 2862 s = entry->start; 2863 e = entry->end; 2864 2865 offidxstart = OFF_TO_IDX(offset); 2866 offidxend = offidxstart + OFF_TO_IDX(e - s); 2867 size = offidxend - offidxstart; 2868 2869 switch(orig_object->type) { 2870 case OBJT_DEFAULT: 2871 new_object = default_pager_alloc(NULL, IDX_TO_OFF(size), 2872 VM_PROT_ALL, 0); 2873 break; 2874 case OBJT_SWAP: 2875 new_object = swap_pager_alloc(NULL, IDX_TO_OFF(size), 2876 VM_PROT_ALL, 0); 2877 break; 2878 default: 2879 /* not reached */ 2880 new_object = NULL; 2881 KKASSERT(0); 2882 } 2883 if (new_object == NULL) 2884 return; 2885 2886 /* 2887 * vm_token required when manipulating vm_objects. 2888 */ 2889 lwkt_gettoken(&vm_token); 2890 lwkt_gettoken(&vmobj_token); 2891 2892 vm_object_hold(new_object); 2893 2894 source = orig_object->backing_object; 2895 if (source != NULL) { 2896 vm_object_hold(source); 2897 /* Referenced by new_object */ 2898 vm_object_reference_locked(source); 2899 LIST_INSERT_HEAD(&source->shadow_head, 2900 new_object, shadow_list); 2901 vm_object_clear_flag(source, OBJ_ONEMAPPING); 2902 new_object->backing_object_offset = 2903 orig_object->backing_object_offset + 2904 IDX_TO_OFF(offidxstart); 2905 new_object->backing_object = source; 2906 source->shadow_count++; 2907 source->generation++; 2908 vm_object_drop(source); 2909 } 2910 2911 for (idx = 0; idx < size; idx++) { 2912 vm_page_t m; 2913 2914 retry: 2915 m = vm_page_lookup(orig_object, offidxstart + idx); 2916 if (m == NULL) 2917 continue; 2918 2919 /* 2920 * We must wait for pending I/O to complete before we can 2921 * rename the page. 2922 * 2923 * We do not have to VM_PROT_NONE the page as mappings should 2924 * not be changed by this operation. 2925 */ 2926 if (vm_page_sleep_busy(m, TRUE, "spltwt")) 2927 goto retry; 2928 vm_page_busy(m); 2929 vm_page_rename(m, new_object, idx); 2930 /* page automatically made dirty by rename and cache handled */ 2931 vm_page_busy(m); 2932 } 2933 2934 if (orig_object->type == OBJT_SWAP) { 2935 vm_object_pip_add(orig_object, 1); 2936 /* 2937 * copy orig_object pages into new_object 2938 * and destroy unneeded pages in 2939 * shadow object. 2940 */ 2941 swap_pager_copy(orig_object, new_object, offidxstart, 0); 2942 vm_object_pip_wakeup(orig_object); 2943 } 2944 2945 /* 2946 * Wakeup the pages we played with. No spl protection is needed 2947 * for a simple wakeup. 2948 */ 2949 for (idx = 0; idx < size; idx++) { 2950 m = vm_page_lookup(new_object, idx); 2951 if (m) 2952 vm_page_wakeup(m); 2953 } 2954 2955 entry->object.vm_object = new_object; 2956 entry->offset = 0LL; 2957 vm_object_deallocate_locked(orig_object); 2958 vm_object_drop(new_object); 2959 lwkt_reltoken(&vmobj_token); 2960 lwkt_reltoken(&vm_token); 2961 } 2962 2963 /* 2964 * Copies the contents of the source entry to the destination 2965 * entry. The entries *must* be aligned properly. 2966 * 2967 * The vm_map must be exclusively locked. 2968 * vm_token must be held 2969 */ 2970 static void 2971 vm_map_copy_entry(vm_map_t src_map, vm_map_t dst_map, 2972 vm_map_entry_t src_entry, vm_map_entry_t dst_entry) 2973 { 2974 vm_object_t src_object; 2975 2976 if (dst_entry->maptype == VM_MAPTYPE_SUBMAP) 2977 return; 2978 if (src_entry->maptype == VM_MAPTYPE_SUBMAP) 2979 return; 2980 2981 ASSERT_LWKT_TOKEN_HELD(&vm_token); 2982 lwkt_gettoken(&vmobj_token); /* required for collapse */ 2983 2984 if (src_entry->wired_count == 0) { 2985 /* 2986 * If the source entry is marked needs_copy, it is already 2987 * write-protected. 2988 */ 2989 if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) { 2990 pmap_protect(src_map->pmap, 2991 src_entry->start, 2992 src_entry->end, 2993 src_entry->protection & ~VM_PROT_WRITE); 2994 } 2995 2996 /* 2997 * Make a copy of the object. 2998 * 2999 * The object must be locked prior to checking the object type 3000 * and for the call to vm_object_collapse() and vm_map_split(). 3001 * We cannot use *_hold() here because the split code will 3002 * probably try to destroy the object. The lock is a pool 3003 * token and doesn't care. 3004 */ 3005 if ((src_object = src_entry->object.vm_object) != NULL) { 3006 vm_object_lock(src_object); 3007 if ((src_object->handle == NULL) && 3008 (src_object->type == OBJT_DEFAULT || 3009 src_object->type == OBJT_SWAP)) { 3010 vm_object_collapse(src_object); 3011 if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) { 3012 vm_map_split(src_entry); 3013 vm_object_unlock(src_object); 3014 src_object = src_entry->object.vm_object; 3015 vm_object_lock(src_object); 3016 } 3017 } 3018 vm_object_reference_locked(src_object); 3019 vm_object_unlock(src_object); 3020 vm_object_clear_flag(src_object, OBJ_ONEMAPPING); 3021 dst_entry->object.vm_object = src_object; 3022 src_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); 3023 dst_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); 3024 dst_entry->offset = src_entry->offset; 3025 } else { 3026 dst_entry->object.vm_object = NULL; 3027 dst_entry->offset = 0; 3028 } 3029 3030 pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start, 3031 dst_entry->end - dst_entry->start, src_entry->start); 3032 } else { 3033 /* 3034 * Of course, wired down pages can't be set copy-on-write. 3035 * Cause wired pages to be copied into the new map by 3036 * simulating faults (the new pages are pageable) 3037 */ 3038 vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry); 3039 } 3040 lwkt_reltoken(&vmobj_token); 3041 } 3042 3043 /* 3044 * vmspace_fork: 3045 * Create a new process vmspace structure and vm_map 3046 * based on those of an existing process. The new map 3047 * is based on the old map, according to the inheritance 3048 * values on the regions in that map. 3049 * 3050 * The source map must not be locked. 3051 * No requirements. 3052 */ 3053 struct vmspace * 3054 vmspace_fork(struct vmspace *vm1) 3055 { 3056 struct vmspace *vm2; 3057 vm_map_t old_map = &vm1->vm_map; 3058 vm_map_t new_map; 3059 vm_map_entry_t old_entry; 3060 vm_map_entry_t new_entry; 3061 vm_object_t object; 3062 int count; 3063 3064 lwkt_gettoken(&vm_token); 3065 lwkt_gettoken(&vmspace_token); 3066 lwkt_gettoken(&vmobj_token); 3067 vm_map_lock(old_map); 3068 3069 /* 3070 * XXX Note: upcalls are not copied. 3071 */ 3072 vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset); 3073 bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy, 3074 (caddr_t)&vm1->vm_endcopy - (caddr_t)&vm1->vm_startcopy); 3075 new_map = &vm2->vm_map; /* XXX */ 3076 new_map->timestamp = 1; 3077 3078 vm_map_lock(new_map); 3079 3080 count = 0; 3081 old_entry = old_map->header.next; 3082 while (old_entry != &old_map->header) { 3083 ++count; 3084 old_entry = old_entry->next; 3085 } 3086 3087 count = vm_map_entry_reserve(count + MAP_RESERVE_COUNT); 3088 3089 old_entry = old_map->header.next; 3090 while (old_entry != &old_map->header) { 3091 if (old_entry->maptype == VM_MAPTYPE_SUBMAP) 3092 panic("vm_map_fork: encountered a submap"); 3093 3094 switch (old_entry->inheritance) { 3095 case VM_INHERIT_NONE: 3096 break; 3097 case VM_INHERIT_SHARE: 3098 /* 3099 * Clone the entry, creating the shared object if 3100 * necessary. 3101 */ 3102 object = old_entry->object.vm_object; 3103 if (object == NULL) { 3104 vm_map_entry_allocate_object(old_entry); 3105 object = old_entry->object.vm_object; 3106 } 3107 3108 /* 3109 * Add the reference before calling vm_map_entry_shadow 3110 * to insure that a shadow object is created. 3111 */ 3112 vm_object_reference_locked(object); 3113 if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3114 vm_map_entry_shadow(old_entry); 3115 /* Transfer the second reference too. */ 3116 vm_object_reference_locked( 3117 old_entry->object.vm_object); 3118 vm_object_deallocate_locked(object); 3119 object = old_entry->object.vm_object; 3120 } 3121 vm_object_clear_flag(object, OBJ_ONEMAPPING); 3122 3123 /* 3124 * Clone the entry, referencing the shared object. 3125 */ 3126 new_entry = vm_map_entry_create(new_map, &count); 3127 *new_entry = *old_entry; 3128 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3129 new_entry->wired_count = 0; 3130 3131 /* 3132 * Insert the entry into the new map -- we know we're 3133 * inserting at the end of the new map. 3134 */ 3135 3136 vm_map_entry_link(new_map, new_map->header.prev, 3137 new_entry); 3138 3139 /* 3140 * Update the physical map 3141 */ 3142 pmap_copy(new_map->pmap, old_map->pmap, 3143 new_entry->start, 3144 (old_entry->end - old_entry->start), 3145 old_entry->start); 3146 break; 3147 case VM_INHERIT_COPY: 3148 /* 3149 * Clone the entry and link into the map. 3150 */ 3151 new_entry = vm_map_entry_create(new_map, &count); 3152 *new_entry = *old_entry; 3153 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3154 new_entry->wired_count = 0; 3155 new_entry->object.vm_object = NULL; 3156 vm_map_entry_link(new_map, new_map->header.prev, 3157 new_entry); 3158 vm_map_copy_entry(old_map, new_map, old_entry, 3159 new_entry); 3160 break; 3161 } 3162 old_entry = old_entry->next; 3163 } 3164 3165 new_map->size = old_map->size; 3166 vm_map_unlock(old_map); 3167 vm_map_unlock(new_map); 3168 vm_map_entry_release(count); 3169 3170 lwkt_reltoken(&vmobj_token); 3171 lwkt_reltoken(&vmspace_token); 3172 lwkt_reltoken(&vm_token); 3173 3174 return (vm2); 3175 } 3176 3177 /* 3178 * Create an auto-grow stack entry 3179 * 3180 * No requirements. 3181 */ 3182 int 3183 vm_map_stack (vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, 3184 int flags, vm_prot_t prot, vm_prot_t max, int cow) 3185 { 3186 vm_map_entry_t prev_entry; 3187 vm_map_entry_t new_stack_entry; 3188 vm_size_t init_ssize; 3189 int rv; 3190 int count; 3191 vm_offset_t tmpaddr; 3192 3193 cow |= MAP_IS_STACK; 3194 3195 if (max_ssize < sgrowsiz) 3196 init_ssize = max_ssize; 3197 else 3198 init_ssize = sgrowsiz; 3199 3200 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3201 vm_map_lock(map); 3202 3203 /* 3204 * Find space for the mapping 3205 */ 3206 if ((flags & (MAP_FIXED | MAP_TRYFIXED)) == 0) { 3207 if (vm_map_findspace(map, addrbos, max_ssize, 1, 3208 flags, &tmpaddr)) { 3209 vm_map_unlock(map); 3210 vm_map_entry_release(count); 3211 return (KERN_NO_SPACE); 3212 } 3213 addrbos = tmpaddr; 3214 } 3215 3216 /* If addr is already mapped, no go */ 3217 if (vm_map_lookup_entry(map, addrbos, &prev_entry)) { 3218 vm_map_unlock(map); 3219 vm_map_entry_release(count); 3220 return (KERN_NO_SPACE); 3221 } 3222 3223 #if 0 3224 /* XXX already handled by kern_mmap() */ 3225 /* If we would blow our VMEM resource limit, no go */ 3226 if (map->size + init_ssize > 3227 curproc->p_rlimit[RLIMIT_VMEM].rlim_cur) { 3228 vm_map_unlock(map); 3229 vm_map_entry_release(count); 3230 return (KERN_NO_SPACE); 3231 } 3232 #endif 3233 3234 /* 3235 * If we can't accomodate max_ssize in the current mapping, 3236 * no go. However, we need to be aware that subsequent user 3237 * mappings might map into the space we have reserved for 3238 * stack, and currently this space is not protected. 3239 * 3240 * Hopefully we will at least detect this condition 3241 * when we try to grow the stack. 3242 */ 3243 if ((prev_entry->next != &map->header) && 3244 (prev_entry->next->start < addrbos + max_ssize)) { 3245 vm_map_unlock(map); 3246 vm_map_entry_release(count); 3247 return (KERN_NO_SPACE); 3248 } 3249 3250 /* 3251 * We initially map a stack of only init_ssize. We will 3252 * grow as needed later. Since this is to be a grow 3253 * down stack, we map at the top of the range. 3254 * 3255 * Note: we would normally expect prot and max to be 3256 * VM_PROT_ALL, and cow to be 0. Possibly we should 3257 * eliminate these as input parameters, and just 3258 * pass these values here in the insert call. 3259 */ 3260 rv = vm_map_insert(map, &count, 3261 NULL, 0, addrbos + max_ssize - init_ssize, 3262 addrbos + max_ssize, 3263 VM_MAPTYPE_NORMAL, 3264 prot, max, 3265 cow); 3266 3267 /* Now set the avail_ssize amount */ 3268 if (rv == KERN_SUCCESS) { 3269 if (prev_entry != &map->header) 3270 vm_map_clip_end(map, prev_entry, addrbos + max_ssize - init_ssize, &count); 3271 new_stack_entry = prev_entry->next; 3272 if (new_stack_entry->end != addrbos + max_ssize || 3273 new_stack_entry->start != addrbos + max_ssize - init_ssize) 3274 panic ("Bad entry start/end for new stack entry"); 3275 else 3276 new_stack_entry->aux.avail_ssize = max_ssize - init_ssize; 3277 } 3278 3279 vm_map_unlock(map); 3280 vm_map_entry_release(count); 3281 return (rv); 3282 } 3283 3284 /* 3285 * Attempts to grow a vm stack entry. Returns KERN_SUCCESS if the 3286 * desired address is already mapped, or if we successfully grow 3287 * the stack. Also returns KERN_SUCCESS if addr is outside the 3288 * stack range (this is strange, but preserves compatibility with 3289 * the grow function in vm_machdep.c). 3290 * 3291 * No requirements. 3292 */ 3293 int 3294 vm_map_growstack (struct proc *p, vm_offset_t addr) 3295 { 3296 vm_map_entry_t prev_entry; 3297 vm_map_entry_t stack_entry; 3298 vm_map_entry_t new_stack_entry; 3299 struct vmspace *vm = p->p_vmspace; 3300 vm_map_t map = &vm->vm_map; 3301 vm_offset_t end; 3302 int grow_amount; 3303 int rv = KERN_SUCCESS; 3304 int is_procstack; 3305 int use_read_lock = 1; 3306 int count; 3307 3308 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3309 Retry: 3310 if (use_read_lock) 3311 vm_map_lock_read(map); 3312 else 3313 vm_map_lock(map); 3314 3315 /* If addr is already in the entry range, no need to grow.*/ 3316 if (vm_map_lookup_entry(map, addr, &prev_entry)) 3317 goto done; 3318 3319 if ((stack_entry = prev_entry->next) == &map->header) 3320 goto done; 3321 if (prev_entry == &map->header) 3322 end = stack_entry->start - stack_entry->aux.avail_ssize; 3323 else 3324 end = prev_entry->end; 3325 3326 /* 3327 * This next test mimics the old grow function in vm_machdep.c. 3328 * It really doesn't quite make sense, but we do it anyway 3329 * for compatibility. 3330 * 3331 * If not growable stack, return success. This signals the 3332 * caller to proceed as he would normally with normal vm. 3333 */ 3334 if (stack_entry->aux.avail_ssize < 1 || 3335 addr >= stack_entry->start || 3336 addr < stack_entry->start - stack_entry->aux.avail_ssize) { 3337 goto done; 3338 } 3339 3340 /* Find the minimum grow amount */ 3341 grow_amount = roundup (stack_entry->start - addr, PAGE_SIZE); 3342 if (grow_amount > stack_entry->aux.avail_ssize) { 3343 rv = KERN_NO_SPACE; 3344 goto done; 3345 } 3346 3347 /* 3348 * If there is no longer enough space between the entries 3349 * nogo, and adjust the available space. Note: this 3350 * should only happen if the user has mapped into the 3351 * stack area after the stack was created, and is 3352 * probably an error. 3353 * 3354 * This also effectively destroys any guard page the user 3355 * might have intended by limiting the stack size. 3356 */ 3357 if (grow_amount > stack_entry->start - end) { 3358 if (use_read_lock && vm_map_lock_upgrade(map)) { 3359 use_read_lock = 0; 3360 goto Retry; 3361 } 3362 use_read_lock = 0; 3363 stack_entry->aux.avail_ssize = stack_entry->start - end; 3364 rv = KERN_NO_SPACE; 3365 goto done; 3366 } 3367 3368 is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr; 3369 3370 /* If this is the main process stack, see if we're over the 3371 * stack limit. 3372 */ 3373 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > 3374 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 3375 rv = KERN_NO_SPACE; 3376 goto done; 3377 } 3378 3379 /* Round up the grow amount modulo SGROWSIZ */ 3380 grow_amount = roundup (grow_amount, sgrowsiz); 3381 if (grow_amount > stack_entry->aux.avail_ssize) { 3382 grow_amount = stack_entry->aux.avail_ssize; 3383 } 3384 if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > 3385 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 3386 grow_amount = p->p_rlimit[RLIMIT_STACK].rlim_cur - 3387 ctob(vm->vm_ssize); 3388 } 3389 3390 /* If we would blow our VMEM resource limit, no go */ 3391 if (map->size + grow_amount > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { 3392 rv = KERN_NO_SPACE; 3393 goto done; 3394 } 3395 3396 if (use_read_lock && vm_map_lock_upgrade(map)) { 3397 use_read_lock = 0; 3398 goto Retry; 3399 } 3400 use_read_lock = 0; 3401 3402 /* Get the preliminary new entry start value */ 3403 addr = stack_entry->start - grow_amount; 3404 3405 /* If this puts us into the previous entry, cut back our growth 3406 * to the available space. Also, see the note above. 3407 */ 3408 if (addr < end) { 3409 stack_entry->aux.avail_ssize = stack_entry->start - end; 3410 addr = end; 3411 } 3412 3413 rv = vm_map_insert(map, &count, 3414 NULL, 0, addr, stack_entry->start, 3415 VM_MAPTYPE_NORMAL, 3416 VM_PROT_ALL, VM_PROT_ALL, 3417 0); 3418 3419 /* Adjust the available stack space by the amount we grew. */ 3420 if (rv == KERN_SUCCESS) { 3421 if (prev_entry != &map->header) 3422 vm_map_clip_end(map, prev_entry, addr, &count); 3423 new_stack_entry = prev_entry->next; 3424 if (new_stack_entry->end != stack_entry->start || 3425 new_stack_entry->start != addr) 3426 panic ("Bad stack grow start/end in new stack entry"); 3427 else { 3428 new_stack_entry->aux.avail_ssize = 3429 stack_entry->aux.avail_ssize - 3430 (new_stack_entry->end - new_stack_entry->start); 3431 if (is_procstack) 3432 vm->vm_ssize += btoc(new_stack_entry->end - 3433 new_stack_entry->start); 3434 } 3435 3436 if (map->flags & MAP_WIREFUTURE) 3437 vm_map_unwire(map, new_stack_entry->start, 3438 new_stack_entry->end, FALSE); 3439 } 3440 3441 done: 3442 if (use_read_lock) 3443 vm_map_unlock_read(map); 3444 else 3445 vm_map_unlock(map); 3446 vm_map_entry_release(count); 3447 return (rv); 3448 } 3449 3450 /* 3451 * Unshare the specified VM space for exec. If other processes are 3452 * mapped to it, then create a new one. The new vmspace is null. 3453 * 3454 * No requirements. 3455 */ 3456 void 3457 vmspace_exec(struct proc *p, struct vmspace *vmcopy) 3458 { 3459 struct vmspace *oldvmspace = p->p_vmspace; 3460 struct vmspace *newvmspace; 3461 vm_map_t map = &p->p_vmspace->vm_map; 3462 3463 /* 3464 * If we are execing a resident vmspace we fork it, otherwise 3465 * we create a new vmspace. Note that exitingcnt and upcalls 3466 * are not copied to the new vmspace. 3467 */ 3468 lwkt_gettoken(&vmspace_token); 3469 if (vmcopy) { 3470 newvmspace = vmspace_fork(vmcopy); 3471 } else { 3472 newvmspace = vmspace_alloc(map->min_offset, map->max_offset); 3473 bcopy(&oldvmspace->vm_startcopy, &newvmspace->vm_startcopy, 3474 (caddr_t)&oldvmspace->vm_endcopy - 3475 (caddr_t)&oldvmspace->vm_startcopy); 3476 } 3477 3478 /* 3479 * Finish initializing the vmspace before assigning it 3480 * to the process. The vmspace will become the current vmspace 3481 * if p == curproc. 3482 */ 3483 pmap_pinit2(vmspace_pmap(newvmspace)); 3484 pmap_replacevm(p, newvmspace, 0); 3485 sysref_put(&oldvmspace->vm_sysref); 3486 lwkt_reltoken(&vmspace_token); 3487 } 3488 3489 /* 3490 * Unshare the specified VM space for forcing COW. This 3491 * is called by rfork, for the (RFMEM|RFPROC) == 0 case. 3492 * 3493 * The exitingcnt test is not strictly necessary but has been 3494 * included for code sanity (to make the code a bit more deterministic). 3495 */ 3496 void 3497 vmspace_unshare(struct proc *p) 3498 { 3499 struct vmspace *oldvmspace = p->p_vmspace; 3500 struct vmspace *newvmspace; 3501 3502 lwkt_gettoken(&vmspace_token); 3503 if (oldvmspace->vm_sysref.refcnt == 1 && oldvmspace->vm_exitingcnt == 0) 3504 return; 3505 newvmspace = vmspace_fork(oldvmspace); 3506 pmap_pinit2(vmspace_pmap(newvmspace)); 3507 pmap_replacevm(p, newvmspace, 0); 3508 sysref_put(&oldvmspace->vm_sysref); 3509 lwkt_reltoken(&vmspace_token); 3510 } 3511 3512 /* 3513 * vm_map_hint: return the beginning of the best area suitable for 3514 * creating a new mapping with "prot" protection. 3515 * 3516 * No requirements. 3517 */ 3518 vm_offset_t 3519 vm_map_hint(struct proc *p, vm_offset_t addr, vm_prot_t prot) 3520 { 3521 struct vmspace *vms = p->p_vmspace; 3522 3523 if (!randomize_mmap) { 3524 /* 3525 * Set a reasonable start point for the hint if it was 3526 * not specified or if it falls within the heap space. 3527 * Hinted mmap()s do not allocate out of the heap space. 3528 */ 3529 if (addr == 0 || 3530 (addr >= round_page((vm_offset_t)vms->vm_taddr) && 3531 addr < round_page((vm_offset_t)vms->vm_daddr + maxdsiz))) { 3532 addr = round_page((vm_offset_t)vms->vm_daddr + maxdsiz); 3533 } 3534 3535 return addr; 3536 } 3537 3538 if (addr != 0 && addr >= (vm_offset_t)vms->vm_daddr) 3539 return addr; 3540 3541 #ifdef notyet 3542 #ifdef __i386__ 3543 /* 3544 * If executable skip first two pages, otherwise start 3545 * after data + heap region. 3546 */ 3547 if ((prot & VM_PROT_EXECUTE) && 3548 ((vm_offset_t)vms->vm_daddr >= I386_MAX_EXE_ADDR)) { 3549 addr = (PAGE_SIZE * 2) + 3550 (karc4random() & (I386_MAX_EXE_ADDR / 2 - 1)); 3551 return (round_page(addr)); 3552 } 3553 #endif /* __i386__ */ 3554 #endif /* notyet */ 3555 3556 addr = (vm_offset_t)vms->vm_daddr + MAXDSIZ; 3557 addr += karc4random() & (MIN((256 * 1024 * 1024), MAXDSIZ) - 1); 3558 3559 return (round_page(addr)); 3560 } 3561 3562 /* 3563 * Finds the VM object, offset, and protection for a given virtual address 3564 * in the specified map, assuming a page fault of the type specified. 3565 * 3566 * Leaves the map in question locked for read; return values are guaranteed 3567 * until a vm_map_lookup_done call is performed. Note that the map argument 3568 * is in/out; the returned map must be used in the call to vm_map_lookup_done. 3569 * 3570 * A handle (out_entry) is returned for use in vm_map_lookup_done, to make 3571 * that fast. 3572 * 3573 * If a lookup is requested with "write protection" specified, the map may 3574 * be changed to perform virtual copying operations, although the data 3575 * referenced will remain the same. 3576 * 3577 * No requirements. 3578 */ 3579 int 3580 vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ 3581 vm_offset_t vaddr, 3582 vm_prot_t fault_typea, 3583 vm_map_entry_t *out_entry, /* OUT */ 3584 vm_object_t *object, /* OUT */ 3585 vm_pindex_t *pindex, /* OUT */ 3586 vm_prot_t *out_prot, /* OUT */ 3587 boolean_t *wired) /* OUT */ 3588 { 3589 vm_map_entry_t entry; 3590 vm_map_t map = *var_map; 3591 vm_prot_t prot; 3592 vm_prot_t fault_type = fault_typea; 3593 int use_read_lock = 1; 3594 int rv = KERN_SUCCESS; 3595 3596 RetryLookup: 3597 if (use_read_lock) 3598 vm_map_lock_read(map); 3599 else 3600 vm_map_lock(map); 3601 3602 /* 3603 * If the map has an interesting hint, try it before calling full 3604 * blown lookup routine. 3605 */ 3606 entry = map->hint; 3607 *out_entry = entry; 3608 3609 if ((entry == &map->header) || 3610 (vaddr < entry->start) || (vaddr >= entry->end)) { 3611 vm_map_entry_t tmp_entry; 3612 3613 /* 3614 * Entry was either not a valid hint, or the vaddr was not 3615 * contained in the entry, so do a full lookup. 3616 */ 3617 if (!vm_map_lookup_entry(map, vaddr, &tmp_entry)) { 3618 rv = KERN_INVALID_ADDRESS; 3619 goto done; 3620 } 3621 3622 entry = tmp_entry; 3623 *out_entry = entry; 3624 } 3625 3626 /* 3627 * Handle submaps. 3628 */ 3629 if (entry->maptype == VM_MAPTYPE_SUBMAP) { 3630 vm_map_t old_map = map; 3631 3632 *var_map = map = entry->object.sub_map; 3633 if (use_read_lock) 3634 vm_map_unlock_read(old_map); 3635 else 3636 vm_map_unlock(old_map); 3637 use_read_lock = 1; 3638 goto RetryLookup; 3639 } 3640 3641 /* 3642 * Check whether this task is allowed to have this page. 3643 * Note the special case for MAP_ENTRY_COW 3644 * pages with an override. This is to implement a forced 3645 * COW for debuggers. 3646 */ 3647 3648 if (fault_type & VM_PROT_OVERRIDE_WRITE) 3649 prot = entry->max_protection; 3650 else 3651 prot = entry->protection; 3652 3653 fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 3654 if ((fault_type & prot) != fault_type) { 3655 rv = KERN_PROTECTION_FAILURE; 3656 goto done; 3657 } 3658 3659 if ((entry->eflags & MAP_ENTRY_USER_WIRED) && 3660 (entry->eflags & MAP_ENTRY_COW) && 3661 (fault_type & VM_PROT_WRITE) && 3662 (fault_typea & VM_PROT_OVERRIDE_WRITE) == 0) { 3663 rv = KERN_PROTECTION_FAILURE; 3664 goto done; 3665 } 3666 3667 /* 3668 * If this page is not pageable, we have to get it for all possible 3669 * accesses. 3670 */ 3671 *wired = (entry->wired_count != 0); 3672 if (*wired) 3673 prot = fault_type = entry->protection; 3674 3675 /* 3676 * Virtual page tables may need to update the accessed (A) bit 3677 * in a page table entry. Upgrade the fault to a write fault for 3678 * that case if the map will support it. If the map does not support 3679 * it the page table entry simply will not be updated. 3680 */ 3681 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 3682 if (prot & VM_PROT_WRITE) 3683 fault_type |= VM_PROT_WRITE; 3684 } 3685 3686 /* 3687 * If the entry was copy-on-write, we either ... 3688 */ 3689 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3690 /* 3691 * If we want to write the page, we may as well handle that 3692 * now since we've got the map locked. 3693 * 3694 * If we don't need to write the page, we just demote the 3695 * permissions allowed. 3696 */ 3697 3698 if (fault_type & VM_PROT_WRITE) { 3699 /* 3700 * Make a new object, and place it in the object 3701 * chain. Note that no new references have appeared 3702 * -- one just moved from the map to the new 3703 * object. 3704 */ 3705 3706 if (use_read_lock && vm_map_lock_upgrade(map)) { 3707 use_read_lock = 0; 3708 goto RetryLookup; 3709 } 3710 use_read_lock = 0; 3711 3712 vm_map_entry_shadow(entry); 3713 } else { 3714 /* 3715 * We're attempting to read a copy-on-write page -- 3716 * don't allow writes. 3717 */ 3718 3719 prot &= ~VM_PROT_WRITE; 3720 } 3721 } 3722 3723 /* 3724 * Create an object if necessary. 3725 */ 3726 if (entry->object.vm_object == NULL && 3727 !map->system_map) { 3728 if (use_read_lock && vm_map_lock_upgrade(map)) { 3729 use_read_lock = 0; 3730 goto RetryLookup; 3731 } 3732 use_read_lock = 0; 3733 vm_map_entry_allocate_object(entry); 3734 } 3735 3736 /* 3737 * Return the object/offset from this entry. If the entry was 3738 * copy-on-write or empty, it has been fixed up. 3739 */ 3740 3741 *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); 3742 *object = entry->object.vm_object; 3743 3744 /* 3745 * Return whether this is the only map sharing this data. On 3746 * success we return with a read lock held on the map. On failure 3747 * we return with the map unlocked. 3748 */ 3749 *out_prot = prot; 3750 done: 3751 if (rv == KERN_SUCCESS) { 3752 if (use_read_lock == 0) 3753 vm_map_lock_downgrade(map); 3754 } else if (use_read_lock) { 3755 vm_map_unlock_read(map); 3756 } else { 3757 vm_map_unlock(map); 3758 } 3759 return (rv); 3760 } 3761 3762 /* 3763 * Releases locks acquired by a vm_map_lookup() 3764 * (according to the handle returned by that lookup). 3765 * 3766 * No other requirements. 3767 */ 3768 void 3769 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry, int count) 3770 { 3771 /* 3772 * Unlock the main-level map 3773 */ 3774 vm_map_unlock_read(map); 3775 if (count) 3776 vm_map_entry_release(count); 3777 } 3778 3779 #include "opt_ddb.h" 3780 #ifdef DDB 3781 #include <sys/kernel.h> 3782 3783 #include <ddb/ddb.h> 3784 3785 /* 3786 * Debugging only 3787 */ 3788 DB_SHOW_COMMAND(map, vm_map_print) 3789 { 3790 static int nlines; 3791 /* XXX convert args. */ 3792 vm_map_t map = (vm_map_t)addr; 3793 boolean_t full = have_addr; 3794 3795 vm_map_entry_t entry; 3796 3797 db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", 3798 (void *)map, 3799 (void *)map->pmap, map->nentries, map->timestamp); 3800 nlines++; 3801 3802 if (!full && db_indent) 3803 return; 3804 3805 db_indent += 2; 3806 for (entry = map->header.next; entry != &map->header; 3807 entry = entry->next) { 3808 db_iprintf("map entry %p: start=%p, end=%p\n", 3809 (void *)entry, (void *)entry->start, (void *)entry->end); 3810 nlines++; 3811 { 3812 static char *inheritance_name[4] = 3813 {"share", "copy", "none", "donate_copy"}; 3814 3815 db_iprintf(" prot=%x/%x/%s", 3816 entry->protection, 3817 entry->max_protection, 3818 inheritance_name[(int)(unsigned char)entry->inheritance]); 3819 if (entry->wired_count != 0) 3820 db_printf(", wired"); 3821 } 3822 if (entry->maptype == VM_MAPTYPE_SUBMAP) { 3823 /* XXX no %qd in kernel. Truncate entry->offset. */ 3824 db_printf(", share=%p, offset=0x%lx\n", 3825 (void *)entry->object.sub_map, 3826 (long)entry->offset); 3827 nlines++; 3828 if ((entry->prev == &map->header) || 3829 (entry->prev->object.sub_map != 3830 entry->object.sub_map)) { 3831 db_indent += 2; 3832 vm_map_print((db_expr_t)(intptr_t) 3833 entry->object.sub_map, 3834 full, 0, NULL); 3835 db_indent -= 2; 3836 } 3837 } else { 3838 /* XXX no %qd in kernel. Truncate entry->offset. */ 3839 db_printf(", object=%p, offset=0x%lx", 3840 (void *)entry->object.vm_object, 3841 (long)entry->offset); 3842 if (entry->eflags & MAP_ENTRY_COW) 3843 db_printf(", copy (%s)", 3844 (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); 3845 db_printf("\n"); 3846 nlines++; 3847 3848 if ((entry->prev == &map->header) || 3849 (entry->prev->object.vm_object != 3850 entry->object.vm_object)) { 3851 db_indent += 2; 3852 vm_object_print((db_expr_t)(intptr_t) 3853 entry->object.vm_object, 3854 full, 0, NULL); 3855 nlines += 4; 3856 db_indent -= 2; 3857 } 3858 } 3859 } 3860 db_indent -= 2; 3861 if (db_indent == 0) 3862 nlines = 0; 3863 } 3864 3865 /* 3866 * Debugging only 3867 */ 3868 DB_SHOW_COMMAND(procvm, procvm) 3869 { 3870 struct proc *p; 3871 3872 if (have_addr) { 3873 p = (struct proc *) addr; 3874 } else { 3875 p = curproc; 3876 } 3877 3878 db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", 3879 (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, 3880 (void *)vmspace_pmap(p->p_vmspace)); 3881 3882 vm_map_print((db_expr_t)(intptr_t)&p->p_vmspace->vm_map, 1, 0, NULL); 3883 } 3884 3885 #endif /* DDB */ 3886