1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * Copyright (c) 2003-2019 The DragonFly Project. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * The Mach Operating System project at Carnegie-Mellon University. 8 * 9 * This code is derived from software contributed to The DragonFly Project 10 * by Matthew Dillon <dillon@backplane.com> 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_map.c 8.3 (Berkeley) 1/12/94 37 * 38 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 39 * All rights reserved. 40 * 41 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 42 * 43 * Permission to use, copy, modify and distribute this software and 44 * its documentation is hereby granted, provided that both the copyright 45 * notice and this permission notice appear in all copies of the 46 * software, derivative works or modified versions, and any portions 47 * thereof, and that both notices appear in supporting documentation. 48 * 49 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 50 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 51 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 52 * 53 * Carnegie Mellon requests users of this software to return to 54 * 55 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 56 * School of Computer Science 57 * Carnegie Mellon University 58 * Pittsburgh PA 15213-3890 59 * 60 * any improvements or extensions that they make and grant Carnegie the 61 * rights to redistribute these changes. 62 */ 63 #include <sys/param.h> 64 #include <sys/systm.h> 65 #include <sys/kernel.h> 66 #include <sys/proc.h> 67 #include <sys/serialize.h> 68 #include <sys/lock.h> 69 #include <sys/vmmeter.h> 70 #include <sys/mman.h> 71 #include <sys/vnode.h> 72 #include <sys/resourcevar.h> 73 #include <sys/shm.h> 74 #include <sys/tree.h> 75 #include <sys/malloc.h> 76 #include <sys/objcache.h> 77 #include <sys/kern_syscall.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <vm/pmap.h> 82 #include <vm/vm_map.h> 83 #include <vm/vm_page.h> 84 #include <vm/vm_object.h> 85 #include <vm/vm_pager.h> 86 #include <vm/vm_kern.h> 87 #include <vm/vm_extern.h> 88 #include <vm/swap_pager.h> 89 #include <vm/vm_zone.h> 90 91 #include <sys/random.h> 92 #include <sys/sysctl.h> 93 #include <sys/spinlock.h> 94 95 #include <sys/thread2.h> 96 #include <sys/spinlock2.h> 97 98 /* 99 * Virtual memory maps provide for the mapping, protection, and sharing 100 * of virtual memory objects. In addition, this module provides for an 101 * efficient virtual copy of memory from one map to another. 102 * 103 * Synchronization is required prior to most operations. 104 * 105 * Maps consist of an ordered doubly-linked list of simple entries. 106 * A hint and a RB tree is used to speed-up lookups. 107 * 108 * Callers looking to modify maps specify start/end addresses which cause 109 * the related map entry to be clipped if necessary, and then later 110 * recombined if the pieces remained compatible. 111 * 112 * Virtual copy operations are performed by copying VM object references 113 * from one map to another, and then marking both regions as copy-on-write. 114 */ 115 static boolean_t vmspace_ctor(void *obj, void *privdata, int ocflags); 116 static void vmspace_dtor(void *obj, void *privdata); 117 static void vmspace_terminate(struct vmspace *vm, int final); 118 119 MALLOC_DEFINE(M_VMSPACE, "vmspace", "vmspace objcache backingstore"); 120 MALLOC_DEFINE(M_MAP_BACKING, "map_backing", "vm_map_backing to entry"); 121 static struct objcache *vmspace_cache; 122 123 /* 124 * per-cpu page table cross mappings are initialized in early boot 125 * and might require a considerable number of vm_map_entry structures. 126 */ 127 #define MAPENTRYBSP_CACHE (MAXCPU+1) 128 #define MAPENTRYAP_CACHE 8 129 130 /* 131 * Partioning threaded programs with large anonymous memory areas can 132 * improve concurrent fault performance. 133 */ 134 #define MAP_ENTRY_PARTITION_SIZE ((vm_offset_t)(32 * 1024 * 1024)) 135 #define MAP_ENTRY_PARTITION_MASK (MAP_ENTRY_PARTITION_SIZE - 1) 136 137 #define VM_MAP_ENTRY_WITHIN_PARTITION(entry) \ 138 ((((entry)->ba.start ^ (entry)->ba.end) & ~MAP_ENTRY_PARTITION_MASK) == 0) 139 140 static struct vm_zone mapentzone_store; 141 __read_mostly static vm_zone_t mapentzone; 142 143 static struct vm_map_entry map_entry_init[MAX_MAPENT]; 144 static struct vm_map_entry cpu_map_entry_init_bsp[MAPENTRYBSP_CACHE]; 145 static struct vm_map_entry cpu_map_entry_init_ap[MAXCPU][MAPENTRYAP_CACHE]; 146 147 static int randomize_mmap; 148 SYSCTL_INT(_vm, OID_AUTO, randomize_mmap, CTLFLAG_RW, &randomize_mmap, 0, 149 "Randomize mmap offsets"); 150 static int vm_map_relock_enable = 1; 151 SYSCTL_INT(_vm, OID_AUTO, map_relock_enable, CTLFLAG_RW, 152 &vm_map_relock_enable, 0, "insert pop pgtable optimization"); 153 static int vm_map_partition_enable = 1; 154 SYSCTL_INT(_vm, OID_AUTO, map_partition_enable, CTLFLAG_RW, 155 &vm_map_partition_enable, 0, "Break up larger vm_map_entry's"); 156 static int vm_map_backing_limit = 5; 157 SYSCTL_INT(_vm, OID_AUTO, map_backing_limit, CTLFLAG_RW, 158 &vm_map_backing_limit, 0, "ba.backing_ba link depth"); 159 static int vm_map_backing_shadow_test = 1; 160 SYSCTL_INT(_vm, OID_AUTO, map_backing_shadow_test, CTLFLAG_RW, 161 &vm_map_backing_shadow_test, 0, "ba.object shadow test"); 162 163 static void vmspace_drop_notoken(struct vmspace *vm); 164 static void vm_map_entry_shadow(vm_map_entry_t entry); 165 static vm_map_entry_t vm_map_entry_create(int *); 166 static void vm_map_entry_dispose (vm_map_t map, vm_map_entry_t entry, int *); 167 static void vm_map_entry_dispose_ba (vm_map_backing_t ba); 168 static void vm_map_backing_replicated(vm_map_t map, 169 vm_map_entry_t entry, int flags); 170 static void vm_map_backing_adjust_start(vm_map_entry_t entry, 171 vm_ooffset_t start); 172 static void vm_map_backing_adjust_end(vm_map_entry_t entry, 173 vm_ooffset_t end); 174 static void vm_map_backing_attach (vm_map_backing_t ba); 175 static void vm_map_backing_detach (vm_map_backing_t ba); 176 static void _vm_map_clip_end (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 177 static void _vm_map_clip_start (vm_map_t, vm_map_entry_t, vm_offset_t, int *); 178 static void vm_map_entry_delete (vm_map_t, vm_map_entry_t, int *); 179 static void vm_map_entry_unwire (vm_map_t, vm_map_entry_t); 180 static void vm_map_copy_entry (vm_map_t, vm_map_t, vm_map_entry_t, 181 vm_map_entry_t); 182 static void vm_map_unclip_range (vm_map_t map, vm_map_entry_t start_entry, 183 vm_offset_t start, vm_offset_t end, int *countp, int flags); 184 static void vm_map_entry_partition(vm_map_t map, vm_map_entry_t entry, 185 vm_offset_t vaddr, int *countp); 186 187 #define MAP_BACK_CLIPPED 0x0001 188 #define MAP_BACK_BASEOBJREFD 0x0002 189 190 /* 191 * Initialize the vm_map module. Must be called before any other vm_map 192 * routines. 193 * 194 * Map and entry structures are allocated from the general purpose 195 * memory pool with some exceptions: 196 * 197 * - The kernel map is allocated statically. 198 * - Initial kernel map entries are allocated out of a static pool. 199 * - We must set ZONE_SPECIAL here or the early boot code can get 200 * stuck if there are >63 cores. 201 * 202 * These restrictions are necessary since malloc() uses the 203 * maps and requires map entries. 204 * 205 * Called from the low level boot code only. 206 */ 207 void 208 vm_map_startup(void) 209 { 210 mapentzone = &mapentzone_store; 211 zbootinit(mapentzone, "MAP ENTRY", sizeof (struct vm_map_entry), 212 map_entry_init, MAX_MAPENT); 213 mapentzone_store.zflags |= ZONE_SPECIAL; 214 } 215 216 /* 217 * Called prior to any vmspace allocations. 218 * 219 * Called from the low level boot code only. 220 */ 221 void 222 vm_init2(void) 223 { 224 vmspace_cache = objcache_create_mbacked(M_VMSPACE, 225 sizeof(struct vmspace), 226 0, ncpus * 4, 227 vmspace_ctor, vmspace_dtor, 228 NULL); 229 zinitna(mapentzone, NULL, 0, 0, ZONE_USE_RESERVE | ZONE_SPECIAL); 230 pmap_init2(); 231 vm_object_init2(); 232 } 233 234 /* 235 * objcache support. We leave the pmap root cached as long as possible 236 * for performance reasons. 237 */ 238 static 239 boolean_t 240 vmspace_ctor(void *obj, void *privdata, int ocflags) 241 { 242 struct vmspace *vm = obj; 243 244 bzero(vm, sizeof(*vm)); 245 vm->vm_refcnt = VM_REF_DELETED; 246 247 return 1; 248 } 249 250 static 251 void 252 vmspace_dtor(void *obj, void *privdata) 253 { 254 struct vmspace *vm = obj; 255 256 KKASSERT(vm->vm_refcnt == VM_REF_DELETED); 257 pmap_puninit(vmspace_pmap(vm)); 258 } 259 260 /* 261 * Red black tree functions 262 * 263 * The caller must hold the related map lock. 264 */ 265 static int rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b); 266 RB_GENERATE(vm_map_rb_tree, vm_map_entry, rb_entry, rb_vm_map_compare); 267 268 /* a->ba.start is address, and the only field which must be initialized */ 269 static int 270 rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b) 271 { 272 if (a->ba.start < b->ba.start) 273 return(-1); 274 else if (a->ba.start > b->ba.start) 275 return(1); 276 return(0); 277 } 278 279 /* 280 * Initialize vmspace ref/hold counts vmspace0. There is a holdcnt for 281 * every refcnt. 282 */ 283 void 284 vmspace_initrefs(struct vmspace *vm) 285 { 286 vm->vm_refcnt = 1; 287 vm->vm_holdcnt = 1; 288 } 289 290 /* 291 * Allocate a vmspace structure, including a vm_map and pmap. 292 * Initialize numerous fields. While the initial allocation is zerod, 293 * subsequence reuse from the objcache leaves elements of the structure 294 * intact (particularly the pmap), so portions must be zerod. 295 * 296 * Returns a referenced vmspace. 297 * 298 * No requirements. 299 */ 300 struct vmspace * 301 vmspace_alloc(vm_offset_t min, vm_offset_t max) 302 { 303 struct vmspace *vm; 304 305 vm = objcache_get(vmspace_cache, M_WAITOK); 306 307 bzero(&vm->vm_startcopy, 308 (char *)&vm->vm_endcopy - (char *)&vm->vm_startcopy); 309 vm_map_init(&vm->vm_map, min, max, NULL); /* initializes token */ 310 311 /* 312 * NOTE: hold to acquires token for safety. 313 * 314 * On return vmspace is referenced (refs=1, hold=1). That is, 315 * each refcnt also has a holdcnt. There can be additional holds 316 * (holdcnt) above and beyond the refcnt. Finalization is handled in 317 * two stages, one on refs 1->0, and the the second on hold 1->0. 318 */ 319 KKASSERT(vm->vm_holdcnt == 0); 320 KKASSERT(vm->vm_refcnt == VM_REF_DELETED); 321 vmspace_initrefs(vm); 322 vmspace_hold(vm); 323 pmap_pinit(vmspace_pmap(vm)); /* (some fields reused) */ 324 vm->vm_map.pmap = vmspace_pmap(vm); /* XXX */ 325 vm->vm_shm = NULL; 326 vm->vm_flags = 0; 327 cpu_vmspace_alloc(vm); 328 vmspace_drop(vm); 329 330 return (vm); 331 } 332 333 /* 334 * NOTE: Can return 0 if the vmspace is exiting. 335 */ 336 int 337 vmspace_getrefs(struct vmspace *vm) 338 { 339 int32_t n; 340 341 n = vm->vm_refcnt; 342 cpu_ccfence(); 343 if (n & VM_REF_DELETED) 344 n = -1; 345 return n; 346 } 347 348 void 349 vmspace_hold(struct vmspace *vm) 350 { 351 atomic_add_int(&vm->vm_holdcnt, 1); 352 lwkt_gettoken(&vm->vm_map.token); 353 } 354 355 /* 356 * Drop with final termination interlock. 357 */ 358 void 359 vmspace_drop(struct vmspace *vm) 360 { 361 lwkt_reltoken(&vm->vm_map.token); 362 vmspace_drop_notoken(vm); 363 } 364 365 static void 366 vmspace_drop_notoken(struct vmspace *vm) 367 { 368 if (atomic_fetchadd_int(&vm->vm_holdcnt, -1) == 1) { 369 if (vm->vm_refcnt & VM_REF_DELETED) 370 vmspace_terminate(vm, 1); 371 } 372 } 373 374 /* 375 * A vmspace object must not be in a terminated state to be able to obtain 376 * additional refs on it. 377 * 378 * These are official references to the vmspace, the count is used to check 379 * for vmspace sharing. Foreign accessors should use 'hold' and not 'ref'. 380 * 381 * XXX we need to combine hold & ref together into one 64-bit field to allow 382 * holds to prevent stage-1 termination. 383 */ 384 void 385 vmspace_ref(struct vmspace *vm) 386 { 387 uint32_t n; 388 389 atomic_add_int(&vm->vm_holdcnt, 1); 390 n = atomic_fetchadd_int(&vm->vm_refcnt, 1); 391 KKASSERT((n & VM_REF_DELETED) == 0); 392 } 393 394 /* 395 * Release a ref on the vmspace. On the 1->0 transition we do stage-1 396 * termination of the vmspace. Then, on the final drop of the hold we 397 * will do stage-2 final termination. 398 */ 399 void 400 vmspace_rel(struct vmspace *vm) 401 { 402 uint32_t n; 403 404 /* 405 * Drop refs. Each ref also has a hold which is also dropped. 406 * 407 * When refs hits 0 compete to get the VM_REF_DELETED flag (hold 408 * prevent finalization) to start termination processing. 409 * Finalization occurs when the last hold count drops to 0. 410 */ 411 n = atomic_fetchadd_int(&vm->vm_refcnt, -1) - 1; 412 while (n == 0) { 413 if (atomic_cmpset_int(&vm->vm_refcnt, 0, VM_REF_DELETED)) { 414 vmspace_terminate(vm, 0); 415 break; 416 } 417 n = vm->vm_refcnt; 418 cpu_ccfence(); 419 } 420 vmspace_drop_notoken(vm); 421 } 422 423 /* 424 * This is called during exit indicating that the vmspace is no 425 * longer in used by an exiting process, but the process has not yet 426 * been reaped. 427 * 428 * We drop refs, allowing for stage-1 termination, but maintain a holdcnt 429 * to prevent stage-2 until the process is reaped. Note hte order of 430 * operation, we must hold first. 431 * 432 * No requirements. 433 */ 434 void 435 vmspace_relexit(struct vmspace *vm) 436 { 437 atomic_add_int(&vm->vm_holdcnt, 1); 438 vmspace_rel(vm); 439 } 440 441 /* 442 * Called during reap to disconnect the remainder of the vmspace from 443 * the process. On the hold drop the vmspace termination is finalized. 444 * 445 * No requirements. 446 */ 447 void 448 vmspace_exitfree(struct proc *p) 449 { 450 struct vmspace *vm; 451 452 vm = p->p_vmspace; 453 p->p_vmspace = NULL; 454 vmspace_drop_notoken(vm); 455 } 456 457 /* 458 * Called in two cases: 459 * 460 * (1) When the last refcnt is dropped and the vmspace becomes inactive, 461 * called with final == 0. refcnt will be (u_int)-1 at this point, 462 * and holdcnt will still be non-zero. 463 * 464 * (2) When holdcnt becomes 0, called with final == 1. There should no 465 * longer be anyone with access to the vmspace. 466 * 467 * VMSPACE_EXIT1 flags the primary deactivation 468 * VMSPACE_EXIT2 flags the last reap 469 */ 470 static void 471 vmspace_terminate(struct vmspace *vm, int final) 472 { 473 int count; 474 475 lwkt_gettoken(&vm->vm_map.token); 476 if (final == 0) { 477 KKASSERT((vm->vm_flags & VMSPACE_EXIT1) == 0); 478 vm->vm_flags |= VMSPACE_EXIT1; 479 480 /* 481 * Get rid of most of the resources. Leave the kernel pmap 482 * intact. 483 * 484 * If the pmap does not contain wired pages we can bulk-delete 485 * the pmap as a performance optimization before removing the 486 * related mappings. 487 * 488 * If the pmap contains wired pages we cannot do this 489 * pre-optimization because currently vm_fault_unwire() 490 * expects the pmap pages to exist and will not decrement 491 * p->wire_count if they do not. 492 */ 493 shmexit(vm); 494 if (vmspace_pmap(vm)->pm_stats.wired_count) { 495 vm_map_remove(&vm->vm_map, VM_MIN_USER_ADDRESS, 496 VM_MAX_USER_ADDRESS); 497 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_USER_ADDRESS, 498 VM_MAX_USER_ADDRESS); 499 } else { 500 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_USER_ADDRESS, 501 VM_MAX_USER_ADDRESS); 502 vm_map_remove(&vm->vm_map, VM_MIN_USER_ADDRESS, 503 VM_MAX_USER_ADDRESS); 504 } 505 lwkt_reltoken(&vm->vm_map.token); 506 } else { 507 KKASSERT((vm->vm_flags & VMSPACE_EXIT1) != 0); 508 KKASSERT((vm->vm_flags & VMSPACE_EXIT2) == 0); 509 510 /* 511 * Get rid of remaining basic resources. 512 */ 513 vm->vm_flags |= VMSPACE_EXIT2; 514 shmexit(vm); 515 516 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 517 vm_map_lock(&vm->vm_map); 518 cpu_vmspace_free(vm); 519 520 /* 521 * Lock the map, to wait out all other references to it. 522 * Delete all of the mappings and pages they hold, then call 523 * the pmap module to reclaim anything left. 524 */ 525 vm_map_delete(&vm->vm_map, 526 vm_map_min(&vm->vm_map), 527 vm_map_max(&vm->vm_map), 528 &count); 529 vm_map_unlock(&vm->vm_map); 530 vm_map_entry_release(count); 531 532 pmap_release(vmspace_pmap(vm)); 533 lwkt_reltoken(&vm->vm_map.token); 534 objcache_put(vmspace_cache, vm); 535 } 536 } 537 538 /* 539 * Swap useage is determined by taking the proportional swap used by 540 * VM objects backing the VM map. To make up for fractional losses, 541 * if the VM object has any swap use at all the associated map entries 542 * count for at least 1 swap page. 543 * 544 * No requirements. 545 */ 546 vm_offset_t 547 vmspace_swap_count(struct vmspace *vm) 548 { 549 vm_map_t map = &vm->vm_map; 550 vm_map_entry_t cur; 551 vm_object_t object; 552 vm_offset_t count = 0; 553 vm_offset_t n; 554 555 vmspace_hold(vm); 556 557 RB_FOREACH(cur, vm_map_rb_tree, &map->rb_root) { 558 switch(cur->maptype) { 559 case VM_MAPTYPE_NORMAL: 560 case VM_MAPTYPE_VPAGETABLE: 561 if ((object = cur->ba.object) == NULL) 562 break; 563 if (object->swblock_count) { 564 n = (cur->ba.end - cur->ba.start) / PAGE_SIZE; 565 count += object->swblock_count * 566 SWAP_META_PAGES * n / object->size + 1; 567 } 568 break; 569 default: 570 break; 571 } 572 } 573 vmspace_drop(vm); 574 575 return(count); 576 } 577 578 /* 579 * Calculate the approximate number of anonymous pages in use by 580 * this vmspace. To make up for fractional losses, we count each 581 * VM object as having at least 1 anonymous page. 582 * 583 * No requirements. 584 */ 585 vm_offset_t 586 vmspace_anonymous_count(struct vmspace *vm) 587 { 588 vm_map_t map = &vm->vm_map; 589 vm_map_entry_t cur; 590 vm_object_t object; 591 vm_offset_t count = 0; 592 593 vmspace_hold(vm); 594 RB_FOREACH(cur, vm_map_rb_tree, &map->rb_root) { 595 switch(cur->maptype) { 596 case VM_MAPTYPE_NORMAL: 597 case VM_MAPTYPE_VPAGETABLE: 598 if ((object = cur->ba.object) == NULL) 599 break; 600 if (object->type != OBJT_DEFAULT && 601 object->type != OBJT_SWAP) { 602 break; 603 } 604 count += object->resident_page_count; 605 break; 606 default: 607 break; 608 } 609 } 610 vmspace_drop(vm); 611 612 return(count); 613 } 614 615 /* 616 * Initialize an existing vm_map structure such as that in the vmspace 617 * structure. The pmap is initialized elsewhere. 618 * 619 * No requirements. 620 */ 621 void 622 vm_map_init(struct vm_map *map, vm_offset_t min_addr, vm_offset_t max_addr, 623 pmap_t pmap) 624 { 625 RB_INIT(&map->rb_root); 626 spin_init(&map->ilock_spin, "ilock"); 627 map->ilock_base = NULL; 628 map->nentries = 0; 629 map->size = 0; 630 map->system_map = 0; 631 vm_map_min(map) = min_addr; 632 vm_map_max(map) = max_addr; 633 map->pmap = pmap; 634 map->timestamp = 0; 635 map->flags = 0; 636 bzero(&map->freehint, sizeof(map->freehint)); 637 lwkt_token_init(&map->token, "vm_map"); 638 lockinit(&map->lock, "vm_maplk", (hz + 9) / 10, 0); 639 } 640 641 /* 642 * Find the first possible free address for the specified request length. 643 * Returns 0 if we don't have one cached. 644 */ 645 static 646 vm_offset_t 647 vm_map_freehint_find(vm_map_t map, vm_size_t length, vm_size_t align) 648 { 649 vm_map_freehint_t *scan; 650 651 scan = &map->freehint[0]; 652 while (scan < &map->freehint[VM_MAP_FFCOUNT]) { 653 if (scan->length == length && scan->align == align) 654 return(scan->start); 655 ++scan; 656 } 657 return 0; 658 } 659 660 /* 661 * Unconditionally set the freehint. Called by vm_map_findspace() after 662 * it finds an address. This will help us iterate optimally on the next 663 * similar findspace. 664 */ 665 static 666 void 667 vm_map_freehint_update(vm_map_t map, vm_offset_t start, 668 vm_size_t length, vm_size_t align) 669 { 670 vm_map_freehint_t *scan; 671 672 scan = &map->freehint[0]; 673 while (scan < &map->freehint[VM_MAP_FFCOUNT]) { 674 if (scan->length == length && scan->align == align) { 675 scan->start = start; 676 return; 677 } 678 ++scan; 679 } 680 scan = &map->freehint[map->freehint_newindex & VM_MAP_FFMASK]; 681 scan->start = start; 682 scan->align = align; 683 scan->length = length; 684 ++map->freehint_newindex; 685 } 686 687 /* 688 * Update any existing freehints (for any alignment), for the hole we just 689 * added. 690 */ 691 static 692 void 693 vm_map_freehint_hole(vm_map_t map, vm_offset_t start, vm_size_t length) 694 { 695 vm_map_freehint_t *scan; 696 697 scan = &map->freehint[0]; 698 while (scan < &map->freehint[VM_MAP_FFCOUNT]) { 699 if (scan->length <= length && scan->start > start) 700 scan->start = start; 701 ++scan; 702 } 703 } 704 705 /* 706 * This function handles MAP_ENTRY_NEEDS_COPY by inserting a fronting 707 * object in the entry for COW faults. 708 * 709 * The entire chain including entry->ba (prior to inserting the fronting 710 * object) essentially becomes set in stone... elements of it can be paged 711 * in or out, but cannot be further modified. 712 * 713 * NOTE: If we do not optimize the backing chain then a unique copy is not 714 * needed. Note, however, that because portions of the chain are 715 * shared across pmaps we cannot make any changes to the vm_map_backing 716 * elements themselves. 717 * 718 * If the map segment is governed by a virtual page table then it is 719 * possible to address offsets beyond the mapped area. Just allocate 720 * a maximally sized object for this case. 721 * 722 * If addref is non-zero an additional reference is added to the returned 723 * entry. This mechanic exists because the additional reference might have 724 * to be added atomically and not after return to prevent a premature 725 * collapse. XXX currently there is no collapse code. 726 * 727 * The vm_map must be exclusively locked. 728 * No other requirements. 729 */ 730 static 731 void 732 vm_map_entry_shadow(vm_map_entry_t entry) 733 { 734 vm_map_backing_t ba; 735 vm_size_t length; 736 vm_object_t source; 737 vm_object_t result; 738 739 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) 740 length = 0x7FFFFFFF; 741 else 742 length = atop(entry->ba.end - entry->ba.start); 743 744 /* 745 * Don't create the new object if the old object isn't shared. 746 * This case occurs quite often when programs fork/exec/wait. 747 * 748 * Caller ensures source exists (all backing_ba's must have objects), 749 * typically indirectly by virtue of the NEEDS_COPY flag being set. 750 * We have a ref on source by virtue of the entry and do not need 751 * to lock it to do this test. 752 */ 753 source = entry->ba.object; 754 KKASSERT(source); 755 756 if (source->type != OBJT_VNODE) { 757 if (source->ref_count == 1 && 758 source->handle == NULL && 759 (source->type == OBJT_DEFAULT || 760 source->type == OBJT_SWAP)) { 761 goto done; 762 } 763 } 764 ba = kmalloc(sizeof(*ba), M_MAP_BACKING, M_INTWAIT); /* copied later */ 765 vm_object_hold_shared(source); 766 767 /* 768 * Once it becomes part of a backing_ba chain it can wind up anywhere, 769 * drop the ONEMAPPING flag now. 770 */ 771 vm_object_clear_flag(source, OBJ_ONEMAPPING); 772 773 /* 774 * Allocate a new object with the given length. The new object 775 * is returned referenced but we may have to add another one. 776 * If we are adding a second reference we must clear OBJ_ONEMAPPING. 777 * (typically because the caller is about to clone a vm_map_entry). 778 * 779 * The source object currently has an extra reference to prevent 780 * collapses into it while we mess with its shadow list, which 781 * we will remove later in this routine. 782 * 783 * The target object may require a second reference if asked for one 784 * by the caller. 785 */ 786 result = vm_object_allocate_hold(OBJT_DEFAULT, length); 787 if (result == NULL) 788 panic("vm_object_shadow: no object for shadowing"); 789 790 /* 791 * The new object shadows the source object. 792 * 793 * Try to optimize the result object's page color when shadowing 794 * in order to maintain page coloring consistency in the combined 795 * shadowed object. 796 * 797 * The source object is moved to ba, retaining its existing ref-count. 798 * No additional ref is needed. 799 * 800 * SHADOWING IS NOT APPLICABLE TO OBJT_VNODE OBJECTS 801 */ 802 vm_map_backing_detach(&entry->ba); 803 *ba = entry->ba; /* previous ba */ 804 entry->ba.object = result; /* new ba (at head of entry) */ 805 entry->ba.backing_ba = ba; 806 entry->ba.backing_count = ba->backing_count + 1; 807 entry->ba.offset = 0; 808 809 /* cpu localization twist */ 810 result->pg_color = vm_quickcolor(); 811 812 vm_map_backing_attach(&entry->ba); 813 vm_map_backing_attach(ba); 814 815 /* 816 * Adjust the return storage. Drop the ref on source before 817 * returning. 818 */ 819 vm_object_drop(result); 820 vm_object_drop(source); 821 done: 822 entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; 823 } 824 825 /* 826 * Allocate an object for a vm_map_entry. 827 * 828 * Object allocation for anonymous mappings is defered as long as possible. 829 * This function is called when we can defer no longer, generally when a map 830 * entry might be split or forked or takes a page fault. 831 * 832 * If the map segment is governed by a virtual page table then it is 833 * possible to address offsets beyond the mapped area. Just allocate 834 * a maximally sized object for this case. 835 * 836 * The vm_map must be exclusively locked. 837 * No other requirements. 838 */ 839 void 840 vm_map_entry_allocate_object(vm_map_entry_t entry) 841 { 842 vm_object_t obj; 843 844 /* 845 * ba.offset is NOT cumulatively added in the backing_ba scan like 846 * it was in the old object chain, so we can assign whatever offset 847 * we like to the new object. 848 * 849 * For now assign a value of 0 to make debugging object sizes 850 * easier. 851 */ 852 entry->ba.offset = 0; 853 854 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 855 /* XXX */ 856 obj = vm_object_allocate(OBJT_DEFAULT, 0x7FFFFFFF); 857 } else { 858 obj = vm_object_allocate(OBJT_DEFAULT, 859 atop(entry->ba.end - entry->ba.start) + 860 entry->ba.offset); 861 } 862 entry->ba.object = obj; 863 vm_map_backing_attach(&entry->ba); 864 } 865 866 /* 867 * Set an initial negative count so the first attempt to reserve 868 * space preloads a bunch of vm_map_entry's for this cpu. Also 869 * pre-allocate 2 vm_map_entries which will be needed by zalloc() to 870 * map a new page for vm_map_entry structures. SMP systems are 871 * particularly sensitive. 872 * 873 * This routine is called in early boot so we cannot just call 874 * vm_map_entry_reserve(). 875 * 876 * Called from the low level boot code only (for each cpu) 877 * 878 * WARNING! Take care not to have too-big a static/BSS structure here 879 * as MAXCPU can be 256+, otherwise the loader's 64MB heap 880 * can get blown out by the kernel plus the initrd image. 881 */ 882 void 883 vm_map_entry_reserve_cpu_init(globaldata_t gd) 884 { 885 vm_map_entry_t entry; 886 int count; 887 int i; 888 889 atomic_add_int(&gd->gd_vme_avail, -MAP_RESERVE_COUNT * 2); 890 if (gd->gd_cpuid == 0) { 891 entry = &cpu_map_entry_init_bsp[0]; 892 count = MAPENTRYBSP_CACHE; 893 } else { 894 entry = &cpu_map_entry_init_ap[gd->gd_cpuid][0]; 895 count = MAPENTRYAP_CACHE; 896 } 897 for (i = 0; i < count; ++i, ++entry) { 898 MAPENT_FREELIST(entry) = gd->gd_vme_base; 899 gd->gd_vme_base = entry; 900 } 901 } 902 903 /* 904 * Reserves vm_map_entry structures so code later-on can manipulate 905 * map_entry structures within a locked map without blocking trying 906 * to allocate a new vm_map_entry. 907 * 908 * No requirements. 909 * 910 * WARNING! We must not decrement gd_vme_avail until after we have 911 * ensured that sufficient entries exist, otherwise we can 912 * get into an endless call recursion in the zalloc code 913 * itself. 914 */ 915 int 916 vm_map_entry_reserve(int count) 917 { 918 struct globaldata *gd = mycpu; 919 vm_map_entry_t entry; 920 921 /* 922 * Make sure we have enough structures in gd_vme_base to handle 923 * the reservation request. 924 * 925 * Use a critical section to protect against VM faults. It might 926 * not be needed, but we have to be careful here. 927 */ 928 if (gd->gd_vme_avail < count) { 929 crit_enter(); 930 while (gd->gd_vme_avail < count) { 931 entry = zalloc(mapentzone); 932 MAPENT_FREELIST(entry) = gd->gd_vme_base; 933 gd->gd_vme_base = entry; 934 atomic_add_int(&gd->gd_vme_avail, 1); 935 } 936 crit_exit(); 937 } 938 atomic_add_int(&gd->gd_vme_avail, -count); 939 940 return(count); 941 } 942 943 /* 944 * Releases previously reserved vm_map_entry structures that were not 945 * used. If we have too much junk in our per-cpu cache clean some of 946 * it out. 947 * 948 * No requirements. 949 */ 950 void 951 vm_map_entry_release(int count) 952 { 953 struct globaldata *gd = mycpu; 954 vm_map_entry_t entry; 955 vm_map_entry_t efree; 956 957 count = atomic_fetchadd_int(&gd->gd_vme_avail, count) + count; 958 if (gd->gd_vme_avail > MAP_RESERVE_SLOP) { 959 efree = NULL; 960 crit_enter(); 961 while (gd->gd_vme_avail > MAP_RESERVE_HYST) { 962 entry = gd->gd_vme_base; 963 KKASSERT(entry != NULL); 964 gd->gd_vme_base = MAPENT_FREELIST(entry); 965 atomic_add_int(&gd->gd_vme_avail, -1); 966 MAPENT_FREELIST(entry) = efree; 967 efree = entry; 968 } 969 crit_exit(); 970 while ((entry = efree) != NULL) { 971 efree = MAPENT_FREELIST(efree); 972 zfree(mapentzone, entry); 973 } 974 } 975 } 976 977 /* 978 * Reserve map entry structures for use in kernel_map itself. These 979 * entries have *ALREADY* been reserved on a per-cpu basis when the map 980 * was inited. This function is used by zalloc() to avoid a recursion 981 * when zalloc() itself needs to allocate additional kernel memory. 982 * 983 * This function works like the normal reserve but does not load the 984 * vm_map_entry cache (because that would result in an infinite 985 * recursion). Note that gd_vme_avail may go negative. This is expected. 986 * 987 * Any caller of this function must be sure to renormalize after 988 * potentially eating entries to ensure that the reserve supply 989 * remains intact. 990 * 991 * No requirements. 992 */ 993 int 994 vm_map_entry_kreserve(int count) 995 { 996 struct globaldata *gd = mycpu; 997 998 atomic_add_int(&gd->gd_vme_avail, -count); 999 KASSERT(gd->gd_vme_base != NULL, 1000 ("no reserved entries left, gd_vme_avail = %d", 1001 gd->gd_vme_avail)); 1002 return(count); 1003 } 1004 1005 /* 1006 * Release previously reserved map entries for kernel_map. We do not 1007 * attempt to clean up like the normal release function as this would 1008 * cause an unnecessary (but probably not fatal) deep procedure call. 1009 * 1010 * No requirements. 1011 */ 1012 void 1013 vm_map_entry_krelease(int count) 1014 { 1015 struct globaldata *gd = mycpu; 1016 1017 atomic_add_int(&gd->gd_vme_avail, count); 1018 } 1019 1020 /* 1021 * Allocates a VM map entry for insertion. No entry fields are filled in. 1022 * 1023 * The entries should have previously been reserved. The reservation count 1024 * is tracked in (*countp). 1025 * 1026 * No requirements. 1027 */ 1028 static vm_map_entry_t 1029 vm_map_entry_create(int *countp) 1030 { 1031 struct globaldata *gd = mycpu; 1032 vm_map_entry_t entry; 1033 1034 KKASSERT(*countp > 0); 1035 --*countp; 1036 crit_enter(); 1037 entry = gd->gd_vme_base; 1038 KASSERT(entry != NULL, ("gd_vme_base NULL! count %d", *countp)); 1039 gd->gd_vme_base = MAPENT_FREELIST(entry); 1040 crit_exit(); 1041 1042 return(entry); 1043 } 1044 1045 /* 1046 * 1047 */ 1048 static void 1049 vm_map_backing_attach(vm_map_backing_t ba) 1050 { 1051 vm_object_t obj = ba->object; 1052 1053 lockmgr(&obj->backing_lk, LK_EXCLUSIVE); 1054 TAILQ_INSERT_TAIL(&obj->backing_list, ba, entry); 1055 lockmgr(&obj->backing_lk, LK_RELEASE); 1056 } 1057 1058 static void 1059 vm_map_backing_detach(vm_map_backing_t ba) 1060 { 1061 vm_object_t obj = ba->object; 1062 1063 lockmgr(&obj->backing_lk, LK_EXCLUSIVE); 1064 TAILQ_REMOVE(&obj->backing_list, ba, entry); 1065 lockmgr(&obj->backing_lk, LK_RELEASE); 1066 } 1067 1068 /* 1069 * Dispose of the dynamically allocated backing_ba chain associated 1070 * with a vm_map_entry. 1071 * 1072 * We decrement the (possibly shared) element and kfree() on the 1073 * 1->0 transition. We only iterate to the next backing_ba when 1074 * the previous one went through a 1->0 transition. 1075 */ 1076 static void 1077 vm_map_entry_dispose_ba(vm_map_backing_t ba) 1078 { 1079 vm_map_backing_t next; 1080 1081 while (ba) { 1082 if (ba->object) { 1083 vm_map_backing_detach(ba); 1084 vm_object_deallocate(ba->object); 1085 } 1086 next = ba->backing_ba; 1087 kfree(ba, M_MAP_BACKING); 1088 ba = next; 1089 } 1090 } 1091 1092 /* 1093 * Dispose of a vm_map_entry that is no longer being referenced. 1094 * 1095 * No requirements. 1096 */ 1097 static void 1098 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry, int *countp) 1099 { 1100 struct globaldata *gd = mycpu; 1101 1102 /* 1103 * Dispose of the base object and the backing link. 1104 */ 1105 switch(entry->maptype) { 1106 case VM_MAPTYPE_NORMAL: 1107 case VM_MAPTYPE_VPAGETABLE: 1108 if (entry->ba.object) { 1109 vm_map_backing_detach(&entry->ba); 1110 vm_object_deallocate(entry->ba.object); 1111 } 1112 break; 1113 case VM_MAPTYPE_SUBMAP: 1114 case VM_MAPTYPE_UKSMAP: 1115 /* XXX TODO */ 1116 break; 1117 default: 1118 break; 1119 } 1120 vm_map_entry_dispose_ba(entry->ba.backing_ba); 1121 1122 /* 1123 * Cleanup for safety. 1124 */ 1125 entry->ba.backing_ba = NULL; 1126 entry->ba.object = NULL; 1127 entry->ba.offset = 0; 1128 1129 ++*countp; 1130 crit_enter(); 1131 MAPENT_FREELIST(entry) = gd->gd_vme_base; 1132 gd->gd_vme_base = entry; 1133 crit_exit(); 1134 } 1135 1136 1137 /* 1138 * Insert/remove entries from maps. 1139 * 1140 * The related map must be exclusively locked. 1141 * The caller must hold map->token 1142 * No other requirements. 1143 */ 1144 static __inline void 1145 vm_map_entry_link(vm_map_t map, vm_map_entry_t entry) 1146 { 1147 ASSERT_VM_MAP_LOCKED(map); 1148 1149 map->nentries++; 1150 if (vm_map_rb_tree_RB_INSERT(&map->rb_root, entry)) 1151 panic("vm_map_entry_link: dup addr map %p ent %p", map, entry); 1152 } 1153 1154 static __inline void 1155 vm_map_entry_unlink(vm_map_t map, 1156 vm_map_entry_t entry) 1157 { 1158 ASSERT_VM_MAP_LOCKED(map); 1159 1160 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1161 panic("vm_map_entry_unlink: attempt to mess with " 1162 "locked entry! %p", entry); 1163 } 1164 vm_map_rb_tree_RB_REMOVE(&map->rb_root, entry); 1165 map->nentries--; 1166 } 1167 1168 /* 1169 * Finds the map entry containing (or immediately preceding) the specified 1170 * address in the given map. The entry is returned in (*entry). 1171 * 1172 * The boolean result indicates whether the address is actually contained 1173 * in the map. 1174 * 1175 * The related map must be locked. 1176 * No other requirements. 1177 */ 1178 boolean_t 1179 vm_map_lookup_entry(vm_map_t map, vm_offset_t address, vm_map_entry_t *entry) 1180 { 1181 vm_map_entry_t tmp; 1182 vm_map_entry_t last; 1183 1184 ASSERT_VM_MAP_LOCKED(map); 1185 1186 /* 1187 * Locate the record from the top of the tree. 'last' tracks the 1188 * closest prior record and is returned if no match is found, which 1189 * in binary tree terms means tracking the most recent right-branch 1190 * taken. If there is no prior record, *entry is set to NULL. 1191 */ 1192 last = NULL; 1193 tmp = RB_ROOT(&map->rb_root); 1194 1195 while (tmp) { 1196 if (address >= tmp->ba.start) { 1197 if (address < tmp->ba.end) { 1198 *entry = tmp; 1199 return(TRUE); 1200 } 1201 last = tmp; 1202 tmp = RB_RIGHT(tmp, rb_entry); 1203 } else { 1204 tmp = RB_LEFT(tmp, rb_entry); 1205 } 1206 } 1207 *entry = last; 1208 return (FALSE); 1209 } 1210 1211 /* 1212 * Inserts the given whole VM object into the target map at the specified 1213 * address range. The object's size should match that of the address range. 1214 * 1215 * The map must be exclusively locked. 1216 * The object must be held. 1217 * The caller must have reserved sufficient vm_map_entry structures. 1218 * 1219 * If object is non-NULL, ref count must be bumped by caller prior to 1220 * making call to account for the new entry. XXX API is a bit messy. 1221 */ 1222 int 1223 vm_map_insert(vm_map_t map, int *countp, void *map_object, void *map_aux, 1224 vm_ooffset_t offset, vm_offset_t start, vm_offset_t end, 1225 vm_maptype_t maptype, vm_subsys_t id, 1226 vm_prot_t prot, vm_prot_t max, int cow) 1227 { 1228 vm_map_entry_t new_entry; 1229 vm_map_entry_t prev_entry; 1230 vm_map_entry_t next; 1231 vm_map_entry_t temp_entry; 1232 vm_eflags_t protoeflags; 1233 vm_object_t object; 1234 int must_drop = 0; 1235 1236 if (maptype == VM_MAPTYPE_UKSMAP) 1237 object = NULL; 1238 else 1239 object = map_object; 1240 1241 ASSERT_VM_MAP_LOCKED(map); 1242 if (object) 1243 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1244 1245 /* 1246 * Check that the start and end points are not bogus. 1247 */ 1248 if ((start < vm_map_min(map)) || (end > vm_map_max(map)) || 1249 (start >= end)) { 1250 return (KERN_INVALID_ADDRESS); 1251 } 1252 1253 /* 1254 * Find the entry prior to the proposed starting address; if it's part 1255 * of an existing entry, this range is bogus. 1256 */ 1257 if (vm_map_lookup_entry(map, start, &temp_entry)) 1258 return (KERN_NO_SPACE); 1259 prev_entry = temp_entry; 1260 1261 /* 1262 * Assert that the next entry doesn't overlap the end point. 1263 */ 1264 if (prev_entry) 1265 next = vm_map_rb_tree_RB_NEXT(prev_entry); 1266 else 1267 next = RB_MIN(vm_map_rb_tree, &map->rb_root); 1268 if (next && next->ba.start < end) 1269 return (KERN_NO_SPACE); 1270 1271 protoeflags = 0; 1272 1273 if (cow & MAP_COPY_ON_WRITE) 1274 protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY; 1275 1276 if (cow & MAP_NOFAULT) { 1277 protoeflags |= MAP_ENTRY_NOFAULT; 1278 1279 KASSERT(object == NULL, 1280 ("vm_map_insert: paradoxical MAP_NOFAULT request")); 1281 } 1282 if (cow & MAP_DISABLE_SYNCER) 1283 protoeflags |= MAP_ENTRY_NOSYNC; 1284 if (cow & MAP_DISABLE_COREDUMP) 1285 protoeflags |= MAP_ENTRY_NOCOREDUMP; 1286 if (cow & MAP_IS_STACK) 1287 protoeflags |= MAP_ENTRY_STACK; 1288 if (cow & MAP_IS_KSTACK) 1289 protoeflags |= MAP_ENTRY_KSTACK; 1290 1291 lwkt_gettoken(&map->token); 1292 1293 if (object) { 1294 ; 1295 } else if (prev_entry && 1296 (prev_entry->eflags == protoeflags) && 1297 (prev_entry->ba.end == start) && 1298 (prev_entry->wired_count == 0) && 1299 (prev_entry->id == id) && 1300 prev_entry->maptype == maptype && 1301 maptype == VM_MAPTYPE_NORMAL && 1302 prev_entry->ba.backing_ba == NULL && /* not backed */ 1303 ((prev_entry->ba.object == NULL) || 1304 vm_object_coalesce(prev_entry->ba.object, 1305 OFF_TO_IDX(prev_entry->ba.offset), 1306 (vm_size_t)(prev_entry->ba.end - prev_entry->ba.start), 1307 (vm_size_t)(end - prev_entry->ba.end)))) { 1308 /* 1309 * We were able to extend the object. Determine if we 1310 * can extend the previous map entry to include the 1311 * new range as well. 1312 */ 1313 if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) && 1314 (prev_entry->protection == prot) && 1315 (prev_entry->max_protection == max)) { 1316 map->size += (end - prev_entry->ba.end); 1317 vm_map_backing_adjust_end(prev_entry, end); 1318 vm_map_simplify_entry(map, prev_entry, countp); 1319 lwkt_reltoken(&map->token); 1320 return (KERN_SUCCESS); 1321 } 1322 1323 /* 1324 * If we can extend the object but cannot extend the 1325 * map entry, we have to create a new map entry. We 1326 * must bump the ref count on the extended object to 1327 * account for it. object may be NULL. 1328 */ 1329 object = prev_entry->ba.object; 1330 offset = prev_entry->ba.offset + 1331 (prev_entry->ba.end - prev_entry->ba.start); 1332 if (object) { 1333 vm_object_hold(object); 1334 vm_object_lock_swap(); /* map->token order */ 1335 vm_object_reference_locked(object); 1336 map_object = object; 1337 must_drop = 1; 1338 } 1339 } 1340 1341 /* 1342 * NOTE: if conditionals fail, object can be NULL here. This occurs 1343 * in things like the buffer map where we manage kva but do not manage 1344 * backing objects. 1345 */ 1346 1347 /* 1348 * Create a new entry 1349 */ 1350 new_entry = vm_map_entry_create(countp); 1351 new_entry->ba.pmap = map->pmap; 1352 new_entry->ba.start = start; 1353 new_entry->ba.end = end; 1354 new_entry->id = id; 1355 1356 new_entry->maptype = maptype; 1357 new_entry->eflags = protoeflags; 1358 new_entry->aux.master_pde = 0; /* in case size is different */ 1359 new_entry->aux.map_aux = map_aux; 1360 new_entry->ba.map_object = map_object; 1361 new_entry->ba.backing_ba = NULL; 1362 new_entry->ba.backing_count = 0; 1363 new_entry->ba.offset = offset; 1364 new_entry->ba.flags = 0; 1365 new_entry->ba.pmap = map->pmap; 1366 1367 new_entry->inheritance = VM_INHERIT_DEFAULT; 1368 new_entry->protection = prot; 1369 new_entry->max_protection = max; 1370 new_entry->wired_count = 0; 1371 1372 /* 1373 * Insert the new entry into the list 1374 */ 1375 vm_map_backing_replicated(map, new_entry, MAP_BACK_BASEOBJREFD); 1376 vm_map_entry_link(map, new_entry); 1377 map->size += new_entry->ba.end - new_entry->ba.start; 1378 1379 /* 1380 * Don't worry about updating freehint[] when inserting, allow 1381 * addresses to be lower than the actual first free spot. 1382 */ 1383 #if 0 1384 /* 1385 * Temporarily removed to avoid MAP_STACK panic, due to 1386 * MAP_STACK being a huge hack. Will be added back in 1387 * when MAP_STACK (and the user stack mapping) is fixed. 1388 */ 1389 /* 1390 * It may be possible to simplify the entry 1391 */ 1392 vm_map_simplify_entry(map, new_entry, countp); 1393 #endif 1394 1395 /* 1396 * Try to pre-populate the page table. Mappings governed by virtual 1397 * page tables cannot be prepopulated without a lot of work, so 1398 * don't try. 1399 */ 1400 if ((cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) && 1401 maptype != VM_MAPTYPE_VPAGETABLE && 1402 maptype != VM_MAPTYPE_UKSMAP) { 1403 int dorelock = 0; 1404 if (vm_map_relock_enable && (cow & MAP_PREFAULT_RELOCK)) { 1405 dorelock = 1; 1406 vm_object_lock_swap(); 1407 vm_object_drop(object); 1408 } 1409 pmap_object_init_pt(map->pmap, new_entry, 1410 new_entry->ba.start, 1411 new_entry->ba.end - new_entry->ba.start, 1412 cow & MAP_PREFAULT_PARTIAL); 1413 if (dorelock) { 1414 vm_object_hold(object); 1415 vm_object_lock_swap(); 1416 } 1417 } 1418 lwkt_reltoken(&map->token); 1419 if (must_drop) 1420 vm_object_drop(object); 1421 1422 return (KERN_SUCCESS); 1423 } 1424 1425 /* 1426 * Find sufficient space for `length' bytes in the given map, starting at 1427 * `start'. Returns 0 on success, 1 on no space. 1428 * 1429 * This function will returned an arbitrarily aligned pointer. If no 1430 * particular alignment is required you should pass align as 1. Note that 1431 * the map may return PAGE_SIZE aligned pointers if all the lengths used in 1432 * the map are a multiple of PAGE_SIZE, even if you pass a smaller align 1433 * argument. 1434 * 1435 * 'align' should be a power of 2 but is not required to be. 1436 * 1437 * The map must be exclusively locked. 1438 * No other requirements. 1439 */ 1440 int 1441 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, 1442 vm_size_t align, int flags, vm_offset_t *addr) 1443 { 1444 vm_map_entry_t entry; 1445 vm_map_entry_t tmp; 1446 vm_offset_t hole_start; 1447 vm_offset_t end; 1448 vm_offset_t align_mask; 1449 1450 if (start < vm_map_min(map)) 1451 start = vm_map_min(map); 1452 if (start > vm_map_max(map)) 1453 return (1); 1454 1455 /* 1456 * If the alignment is not a power of 2 we will have to use 1457 * a mod/division, set align_mask to a special value. 1458 */ 1459 if ((align | (align - 1)) + 1 != (align << 1)) 1460 align_mask = (vm_offset_t)-1; 1461 else 1462 align_mask = align - 1; 1463 1464 /* 1465 * Use freehint to adjust the start point, hopefully reducing 1466 * the iteration to O(1). 1467 */ 1468 hole_start = vm_map_freehint_find(map, length, align); 1469 if (start < hole_start) 1470 start = hole_start; 1471 if (vm_map_lookup_entry(map, start, &tmp)) 1472 start = tmp->ba.end; 1473 entry = tmp; /* may be NULL */ 1474 1475 /* 1476 * Look through the rest of the map, trying to fit a new region in the 1477 * gap between existing regions, or after the very last region. 1478 */ 1479 for (;;) { 1480 /* 1481 * Adjust the proposed start by the requested alignment, 1482 * be sure that we didn't wrap the address. 1483 */ 1484 if (align_mask == (vm_offset_t)-1) 1485 end = roundup(start, align); 1486 else 1487 end = (start + align_mask) & ~align_mask; 1488 if (end < start) 1489 return (1); 1490 start = end; 1491 1492 /* 1493 * Find the end of the proposed new region. Be sure we didn't 1494 * go beyond the end of the map, or wrap around the address. 1495 * Then check to see if this is the last entry or if the 1496 * proposed end fits in the gap between this and the next 1497 * entry. 1498 */ 1499 end = start + length; 1500 if (end > vm_map_max(map) || end < start) 1501 return (1); 1502 1503 /* 1504 * Locate the next entry, we can stop if this is the 1505 * last entry (we know we are in-bounds so that would 1506 * be a sucess). 1507 */ 1508 if (entry) 1509 entry = vm_map_rb_tree_RB_NEXT(entry); 1510 else 1511 entry = RB_MIN(vm_map_rb_tree, &map->rb_root); 1512 if (entry == NULL) 1513 break; 1514 1515 /* 1516 * Determine if the proposed area would overlap the 1517 * next entry. 1518 * 1519 * When matching against a STACK entry, only allow the 1520 * memory map to intrude on the ungrown portion of the 1521 * STACK entry when MAP_TRYFIXED is set. 1522 */ 1523 if (entry->ba.start >= end) { 1524 if ((entry->eflags & MAP_ENTRY_STACK) == 0) 1525 break; 1526 if (flags & MAP_TRYFIXED) 1527 break; 1528 if (entry->ba.start - entry->aux.avail_ssize >= end) 1529 break; 1530 } 1531 start = entry->ba.end; 1532 } 1533 1534 /* 1535 * Update the freehint 1536 */ 1537 vm_map_freehint_update(map, start, length, align); 1538 1539 /* 1540 * Grow the kernel_map if necessary. pmap_growkernel() will panic 1541 * if it fails. The kernel_map is locked and nothing can steal 1542 * our address space if pmap_growkernel() blocks. 1543 * 1544 * NOTE: This may be unconditionally called for kldload areas on 1545 * x86_64 because these do not bump kernel_vm_end (which would 1546 * fill 128G worth of page tables!). Therefore we must not 1547 * retry. 1548 */ 1549 if (map == &kernel_map) { 1550 vm_offset_t kstop; 1551 1552 kstop = round_page(start + length); 1553 if (kstop > kernel_vm_end) 1554 pmap_growkernel(start, kstop); 1555 } 1556 *addr = start; 1557 return (0); 1558 } 1559 1560 /* 1561 * vm_map_find finds an unallocated region in the target address map with 1562 * the given length and allocates it. The search is defined to be first-fit 1563 * from the specified address; the region found is returned in the same 1564 * parameter. 1565 * 1566 * If object is non-NULL, ref count must be bumped by caller 1567 * prior to making call to account for the new entry. 1568 * 1569 * No requirements. This function will lock the map temporarily. 1570 */ 1571 int 1572 vm_map_find(vm_map_t map, void *map_object, void *map_aux, 1573 vm_ooffset_t offset, vm_offset_t *addr, 1574 vm_size_t length, vm_size_t align, boolean_t fitit, 1575 vm_maptype_t maptype, vm_subsys_t id, 1576 vm_prot_t prot, vm_prot_t max, int cow) 1577 { 1578 vm_offset_t start; 1579 vm_object_t object; 1580 int result; 1581 int count; 1582 1583 if (maptype == VM_MAPTYPE_UKSMAP) 1584 object = NULL; 1585 else 1586 object = map_object; 1587 1588 start = *addr; 1589 1590 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1591 vm_map_lock(map); 1592 if (object) 1593 vm_object_hold_shared(object); 1594 if (fitit) { 1595 if (vm_map_findspace(map, start, length, align, 0, addr)) { 1596 if (object) 1597 vm_object_drop(object); 1598 vm_map_unlock(map); 1599 vm_map_entry_release(count); 1600 return (KERN_NO_SPACE); 1601 } 1602 start = *addr; 1603 } 1604 result = vm_map_insert(map, &count, map_object, map_aux, 1605 offset, start, start + length, 1606 maptype, id, prot, max, cow); 1607 if (object) 1608 vm_object_drop(object); 1609 vm_map_unlock(map); 1610 vm_map_entry_release(count); 1611 1612 return (result); 1613 } 1614 1615 /* 1616 * Simplify the given map entry by merging with either neighbor. This 1617 * routine also has the ability to merge with both neighbors. 1618 * 1619 * This routine guarentees that the passed entry remains valid (though 1620 * possibly extended). When merging, this routine may delete one or 1621 * both neighbors. No action is taken on entries which have their 1622 * in-transition flag set. 1623 * 1624 * The map must be exclusively locked. 1625 */ 1626 void 1627 vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry, int *countp) 1628 { 1629 vm_map_entry_t next, prev; 1630 vm_size_t prevsize, esize; 1631 1632 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1633 ++mycpu->gd_cnt.v_intrans_coll; 1634 return; 1635 } 1636 1637 if (entry->maptype == VM_MAPTYPE_SUBMAP) 1638 return; 1639 if (entry->maptype == VM_MAPTYPE_UKSMAP) 1640 return; 1641 1642 prev = vm_map_rb_tree_RB_PREV(entry); 1643 if (prev) { 1644 prevsize = prev->ba.end - prev->ba.start; 1645 if ( (prev->ba.end == entry->ba.start) && 1646 (prev->maptype == entry->maptype) && 1647 (prev->ba.object == entry->ba.object) && 1648 (prev->ba.backing_ba == entry->ba.backing_ba) && 1649 (!prev->ba.object || 1650 (prev->ba.offset + prevsize == entry->ba.offset)) && 1651 (prev->eflags == entry->eflags) && 1652 (prev->protection == entry->protection) && 1653 (prev->max_protection == entry->max_protection) && 1654 (prev->inheritance == entry->inheritance) && 1655 (prev->id == entry->id) && 1656 (prev->wired_count == entry->wired_count)) { 1657 /* 1658 * NOTE: order important. Unlink before gumming up 1659 * the RBTREE w/adjust, adjust before disposal 1660 * of prior entry, to avoid pmap snafus. 1661 */ 1662 vm_map_entry_unlink(map, prev); 1663 vm_map_backing_adjust_start(entry, prev->ba.start); 1664 if (entry->ba.object == NULL) 1665 entry->ba.offset = 0; 1666 vm_map_entry_dispose(map, prev, countp); 1667 } 1668 } 1669 1670 next = vm_map_rb_tree_RB_NEXT(entry); 1671 if (next) { 1672 esize = entry->ba.end - entry->ba.start; 1673 if ((entry->ba.end == next->ba.start) && 1674 (next->maptype == entry->maptype) && 1675 (next->ba.object == entry->ba.object) && 1676 (prev->ba.backing_ba == entry->ba.backing_ba) && 1677 (!entry->ba.object || 1678 (entry->ba.offset + esize == next->ba.offset)) && 1679 (next->eflags == entry->eflags) && 1680 (next->protection == entry->protection) && 1681 (next->max_protection == entry->max_protection) && 1682 (next->inheritance == entry->inheritance) && 1683 (next->id == entry->id) && 1684 (next->wired_count == entry->wired_count)) { 1685 /* 1686 * NOTE: order important. Unlink before gumming up 1687 * the RBTREE w/adjust, adjust before disposal 1688 * of prior entry, to avoid pmap snafus. 1689 */ 1690 vm_map_entry_unlink(map, next); 1691 vm_map_backing_adjust_end(entry, next->ba.end); 1692 vm_map_entry_dispose(map, next, countp); 1693 } 1694 } 1695 } 1696 1697 /* 1698 * Asserts that the given entry begins at or after the specified address. 1699 * If necessary, it splits the entry into two. 1700 */ 1701 #define vm_map_clip_start(map, entry, startaddr, countp) \ 1702 { \ 1703 if (startaddr > entry->ba.start) \ 1704 _vm_map_clip_start(map, entry, startaddr, countp); \ 1705 } 1706 1707 /* 1708 * This routine is called only when it is known that the entry must be split. 1709 * 1710 * The map must be exclusively locked. 1711 */ 1712 static void 1713 _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start, 1714 int *countp) 1715 { 1716 vm_map_entry_t new_entry; 1717 1718 /* 1719 * Split off the front portion -- note that we must insert the new 1720 * entry BEFORE this one, so that this entry has the specified 1721 * starting address. 1722 */ 1723 1724 vm_map_simplify_entry(map, entry, countp); 1725 1726 /* 1727 * If there is no object backing this entry, we might as well create 1728 * one now. If we defer it, an object can get created after the map 1729 * is clipped, and individual objects will be created for the split-up 1730 * map. This is a bit of a hack, but is also about the best place to 1731 * put this improvement. 1732 */ 1733 if (entry->ba.object == NULL && !map->system_map && 1734 VM_MAP_ENTRY_WITHIN_PARTITION(entry)) { 1735 vm_map_entry_allocate_object(entry); 1736 } 1737 1738 /* 1739 * NOTE: The replicated function will adjust start, end, and offset 1740 * for the remainder of the backing_ba linkages. We must fixup 1741 * the embedded ba. 1742 */ 1743 new_entry = vm_map_entry_create(countp); 1744 *new_entry = *entry; 1745 new_entry->ba.end = start; 1746 1747 /* 1748 * Ordering is important, make sure the new entry is replicated 1749 * before we cut the exiting entry. 1750 */ 1751 vm_map_backing_replicated(map, new_entry, MAP_BACK_CLIPPED); 1752 vm_map_backing_adjust_start(entry, start); 1753 vm_map_entry_link(map, new_entry); 1754 } 1755 1756 /* 1757 * Asserts that the given entry ends at or before the specified address. 1758 * If necessary, it splits the entry into two. 1759 * 1760 * The map must be exclusively locked. 1761 */ 1762 #define vm_map_clip_end(map, entry, endaddr, countp) \ 1763 { \ 1764 if (endaddr < entry->ba.end) \ 1765 _vm_map_clip_end(map, entry, endaddr, countp); \ 1766 } 1767 1768 /* 1769 * This routine is called only when it is known that the entry must be split. 1770 * 1771 * The map must be exclusively locked. 1772 */ 1773 static void 1774 _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end, 1775 int *countp) 1776 { 1777 vm_map_entry_t new_entry; 1778 1779 /* 1780 * If there is no object backing this entry, we might as well create 1781 * one now. If we defer it, an object can get created after the map 1782 * is clipped, and individual objects will be created for the split-up 1783 * map. This is a bit of a hack, but is also about the best place to 1784 * put this improvement. 1785 */ 1786 1787 if (entry->ba.object == NULL && !map->system_map && 1788 VM_MAP_ENTRY_WITHIN_PARTITION(entry)) { 1789 vm_map_entry_allocate_object(entry); 1790 } 1791 1792 /* 1793 * Create a new entry and insert it AFTER the specified entry 1794 * 1795 * NOTE: The replicated function will adjust start, end, and offset 1796 * for the remainder of the backing_ba linkages. We must fixup 1797 * the embedded ba. 1798 */ 1799 new_entry = vm_map_entry_create(countp); 1800 *new_entry = *entry; 1801 new_entry->ba.start = end; 1802 new_entry->ba.offset += (new_entry->ba.start - entry->ba.start); 1803 1804 /* 1805 * Ordering is important, make sure the new entry is replicated 1806 * before we cut the exiting entry. 1807 */ 1808 vm_map_backing_replicated(map, new_entry, MAP_BACK_CLIPPED); 1809 vm_map_backing_adjust_end(entry, end); 1810 vm_map_entry_link(map, new_entry); 1811 } 1812 1813 /* 1814 * Asserts that the starting and ending region addresses fall within the 1815 * valid range for the map. 1816 */ 1817 #define VM_MAP_RANGE_CHECK(map, start, end) \ 1818 { \ 1819 if (start < vm_map_min(map)) \ 1820 start = vm_map_min(map); \ 1821 if (end > vm_map_max(map)) \ 1822 end = vm_map_max(map); \ 1823 if (start > end) \ 1824 start = end; \ 1825 } 1826 1827 /* 1828 * Used to block when an in-transition collison occurs. The map 1829 * is unlocked for the sleep and relocked before the return. 1830 */ 1831 void 1832 vm_map_transition_wait(vm_map_t map, int relock) 1833 { 1834 tsleep_interlock(map, 0); 1835 vm_map_unlock(map); 1836 tsleep(map, PINTERLOCKED, "vment", 0); 1837 if (relock) 1838 vm_map_lock(map); 1839 } 1840 1841 /* 1842 * When we do blocking operations with the map lock held it is 1843 * possible that a clip might have occured on our in-transit entry, 1844 * requiring an adjustment to the entry in our loop. These macros 1845 * help the pageable and clip_range code deal with the case. The 1846 * conditional costs virtually nothing if no clipping has occured. 1847 */ 1848 1849 #define CLIP_CHECK_BACK(entry, save_start) \ 1850 do { \ 1851 while (entry->ba.start != save_start) { \ 1852 entry = vm_map_rb_tree_RB_PREV(entry); \ 1853 KASSERT(entry, ("bad entry clip")); \ 1854 } \ 1855 } while(0) 1856 1857 #define CLIP_CHECK_FWD(entry, save_end) \ 1858 do { \ 1859 while (entry->ba.end != save_end) { \ 1860 entry = vm_map_rb_tree_RB_NEXT(entry); \ 1861 KASSERT(entry, ("bad entry clip")); \ 1862 } \ 1863 } while(0) 1864 1865 1866 /* 1867 * Clip the specified range and return the base entry. The 1868 * range may cover several entries starting at the returned base 1869 * and the first and last entry in the covering sequence will be 1870 * properly clipped to the requested start and end address. 1871 * 1872 * If no holes are allowed you should pass the MAP_CLIP_NO_HOLES 1873 * flag. 1874 * 1875 * The MAP_ENTRY_IN_TRANSITION flag will be set for the entries 1876 * covered by the requested range. 1877 * 1878 * The map must be exclusively locked on entry and will remain locked 1879 * on return. If no range exists or the range contains holes and you 1880 * specified that no holes were allowed, NULL will be returned. This 1881 * routine may temporarily unlock the map in order avoid a deadlock when 1882 * sleeping. 1883 */ 1884 static 1885 vm_map_entry_t 1886 vm_map_clip_range(vm_map_t map, vm_offset_t start, vm_offset_t end, 1887 int *countp, int flags) 1888 { 1889 vm_map_entry_t start_entry; 1890 vm_map_entry_t entry; 1891 vm_map_entry_t next; 1892 1893 /* 1894 * Locate the entry and effect initial clipping. The in-transition 1895 * case does not occur very often so do not try to optimize it. 1896 */ 1897 again: 1898 if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) 1899 return (NULL); 1900 entry = start_entry; 1901 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 1902 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1903 ++mycpu->gd_cnt.v_intrans_coll; 1904 ++mycpu->gd_cnt.v_intrans_wait; 1905 vm_map_transition_wait(map, 1); 1906 /* 1907 * entry and/or start_entry may have been clipped while 1908 * we slept, or may have gone away entirely. We have 1909 * to restart from the lookup. 1910 */ 1911 goto again; 1912 } 1913 1914 /* 1915 * Since we hold an exclusive map lock we do not have to restart 1916 * after clipping, even though clipping may block in zalloc. 1917 */ 1918 vm_map_clip_start(map, entry, start, countp); 1919 vm_map_clip_end(map, entry, end, countp); 1920 entry->eflags |= MAP_ENTRY_IN_TRANSITION; 1921 1922 /* 1923 * Scan entries covered by the range. When working on the next 1924 * entry a restart need only re-loop on the current entry which 1925 * we have already locked, since 'next' may have changed. Also, 1926 * even though entry is safe, it may have been clipped so we 1927 * have to iterate forwards through the clip after sleeping. 1928 */ 1929 for (;;) { 1930 next = vm_map_rb_tree_RB_NEXT(entry); 1931 if (next == NULL || next->ba.start >= end) 1932 break; 1933 if (flags & MAP_CLIP_NO_HOLES) { 1934 if (next->ba.start > entry->ba.end) { 1935 vm_map_unclip_range(map, start_entry, 1936 start, entry->ba.end, countp, flags); 1937 return(NULL); 1938 } 1939 } 1940 1941 if (next->eflags & MAP_ENTRY_IN_TRANSITION) { 1942 vm_offset_t save_end = entry->ba.end; 1943 next->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 1944 ++mycpu->gd_cnt.v_intrans_coll; 1945 ++mycpu->gd_cnt.v_intrans_wait; 1946 vm_map_transition_wait(map, 1); 1947 1948 /* 1949 * clips might have occured while we blocked. 1950 */ 1951 CLIP_CHECK_FWD(entry, save_end); 1952 CLIP_CHECK_BACK(start_entry, start); 1953 continue; 1954 } 1955 1956 /* 1957 * No restart necessary even though clip_end may block, we 1958 * are holding the map lock. 1959 */ 1960 vm_map_clip_end(map, next, end, countp); 1961 next->eflags |= MAP_ENTRY_IN_TRANSITION; 1962 entry = next; 1963 } 1964 if (flags & MAP_CLIP_NO_HOLES) { 1965 if (entry->ba.end != end) { 1966 vm_map_unclip_range(map, start_entry, 1967 start, entry->ba.end, countp, flags); 1968 return(NULL); 1969 } 1970 } 1971 return(start_entry); 1972 } 1973 1974 /* 1975 * Undo the effect of vm_map_clip_range(). You should pass the same 1976 * flags and the same range that you passed to vm_map_clip_range(). 1977 * This code will clear the in-transition flag on the entries and 1978 * wake up anyone waiting. This code will also simplify the sequence 1979 * and attempt to merge it with entries before and after the sequence. 1980 * 1981 * The map must be locked on entry and will remain locked on return. 1982 * 1983 * Note that you should also pass the start_entry returned by 1984 * vm_map_clip_range(). However, if you block between the two calls 1985 * with the map unlocked please be aware that the start_entry may 1986 * have been clipped and you may need to scan it backwards to find 1987 * the entry corresponding with the original start address. You are 1988 * responsible for this, vm_map_unclip_range() expects the correct 1989 * start_entry to be passed to it and will KASSERT otherwise. 1990 */ 1991 static 1992 void 1993 vm_map_unclip_range(vm_map_t map, vm_map_entry_t start_entry, 1994 vm_offset_t start, vm_offset_t end, 1995 int *countp, int flags) 1996 { 1997 vm_map_entry_t entry; 1998 1999 entry = start_entry; 2000 2001 KASSERT(entry->ba.start == start, ("unclip_range: illegal base entry")); 2002 while (entry && entry->ba.start < end) { 2003 KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION, 2004 ("in-transition flag not set during unclip on: %p", 2005 entry)); 2006 KASSERT(entry->ba.end <= end, 2007 ("unclip_range: tail wasn't clipped")); 2008 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; 2009 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { 2010 entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; 2011 wakeup(map); 2012 } 2013 entry = vm_map_rb_tree_RB_NEXT(entry); 2014 } 2015 2016 /* 2017 * Simplification does not block so there is no restart case. 2018 */ 2019 entry = start_entry; 2020 while (entry && entry->ba.start < end) { 2021 vm_map_simplify_entry(map, entry, countp); 2022 entry = vm_map_rb_tree_RB_NEXT(entry); 2023 } 2024 } 2025 2026 /* 2027 * Mark the given range as handled by a subordinate map. 2028 * 2029 * This range must have been created with vm_map_find(), and no other 2030 * operations may have been performed on this range prior to calling 2031 * vm_map_submap(). 2032 * 2033 * Submappings cannot be removed. 2034 * 2035 * No requirements. 2036 */ 2037 int 2038 vm_map_submap(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_map_t submap) 2039 { 2040 vm_map_entry_t entry; 2041 int result = KERN_INVALID_ARGUMENT; 2042 int count; 2043 2044 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2045 vm_map_lock(map); 2046 2047 VM_MAP_RANGE_CHECK(map, start, end); 2048 2049 if (vm_map_lookup_entry(map, start, &entry)) { 2050 vm_map_clip_start(map, entry, start, &count); 2051 } else if (entry) { 2052 entry = vm_map_rb_tree_RB_NEXT(entry); 2053 } else { 2054 entry = RB_MIN(vm_map_rb_tree, &map->rb_root); 2055 } 2056 2057 vm_map_clip_end(map, entry, end, &count); 2058 2059 if ((entry->ba.start == start) && (entry->ba.end == end) && 2060 ((entry->eflags & MAP_ENTRY_COW) == 0) && 2061 (entry->ba.object == NULL)) { 2062 entry->ba.sub_map = submap; 2063 entry->maptype = VM_MAPTYPE_SUBMAP; 2064 result = KERN_SUCCESS; 2065 } 2066 vm_map_unlock(map); 2067 vm_map_entry_release(count); 2068 2069 return (result); 2070 } 2071 2072 /* 2073 * Sets the protection of the specified address region in the target map. 2074 * If "set_max" is specified, the maximum protection is to be set; 2075 * otherwise, only the current protection is affected. 2076 * 2077 * The protection is not applicable to submaps, but is applicable to normal 2078 * maps and maps governed by virtual page tables. For example, when operating 2079 * on a virtual page table our protection basically controls how COW occurs 2080 * on the backing object, whereas the virtual page table abstraction itself 2081 * is an abstraction for userland. 2082 * 2083 * No requirements. 2084 */ 2085 int 2086 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, 2087 vm_prot_t new_prot, boolean_t set_max) 2088 { 2089 vm_map_entry_t current; 2090 vm_map_entry_t entry; 2091 int count; 2092 2093 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2094 vm_map_lock(map); 2095 2096 VM_MAP_RANGE_CHECK(map, start, end); 2097 2098 if (vm_map_lookup_entry(map, start, &entry)) { 2099 vm_map_clip_start(map, entry, start, &count); 2100 } else if (entry) { 2101 entry = vm_map_rb_tree_RB_NEXT(entry); 2102 } else { 2103 entry = RB_MIN(vm_map_rb_tree, &map->rb_root); 2104 } 2105 2106 /* 2107 * Make a first pass to check for protection violations. 2108 */ 2109 current = entry; 2110 while (current && current->ba.start < end) { 2111 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2112 vm_map_unlock(map); 2113 vm_map_entry_release(count); 2114 return (KERN_INVALID_ARGUMENT); 2115 } 2116 if ((new_prot & current->max_protection) != new_prot) { 2117 vm_map_unlock(map); 2118 vm_map_entry_release(count); 2119 return (KERN_PROTECTION_FAILURE); 2120 } 2121 2122 /* 2123 * When making a SHARED+RW file mmap writable, update 2124 * v_lastwrite_ts. 2125 */ 2126 if (new_prot & PROT_WRITE && 2127 (current->eflags & MAP_ENTRY_NEEDS_COPY) == 0 && 2128 (current->maptype == VM_MAPTYPE_NORMAL || 2129 current->maptype == VM_MAPTYPE_VPAGETABLE) && 2130 current->ba.object && 2131 current->ba.object->type == OBJT_VNODE) { 2132 struct vnode *vp; 2133 2134 vp = current->ba.object->handle; 2135 if (vp && vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWAIT) == 0) { 2136 vfs_timestamp(&vp->v_lastwrite_ts); 2137 vsetflags(vp, VLASTWRITETS); 2138 vn_unlock(vp); 2139 } 2140 } 2141 current = vm_map_rb_tree_RB_NEXT(current); 2142 } 2143 2144 /* 2145 * Go back and fix up protections. [Note that clipping is not 2146 * necessary the second time.] 2147 */ 2148 current = entry; 2149 2150 while (current && current->ba.start < end) { 2151 vm_prot_t old_prot; 2152 2153 vm_map_clip_end(map, current, end, &count); 2154 2155 old_prot = current->protection; 2156 if (set_max) { 2157 current->max_protection = new_prot; 2158 current->protection = new_prot & old_prot; 2159 } else { 2160 current->protection = new_prot; 2161 } 2162 2163 /* 2164 * Update physical map if necessary. Worry about copy-on-write 2165 * here -- CHECK THIS XXX 2166 */ 2167 if (current->protection != old_prot) { 2168 #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ 2169 VM_PROT_ALL) 2170 2171 pmap_protect(map->pmap, current->ba.start, 2172 current->ba.end, 2173 current->protection & MASK(current)); 2174 #undef MASK 2175 } 2176 2177 vm_map_simplify_entry(map, current, &count); 2178 2179 current = vm_map_rb_tree_RB_NEXT(current); 2180 } 2181 vm_map_unlock(map); 2182 vm_map_entry_release(count); 2183 return (KERN_SUCCESS); 2184 } 2185 2186 /* 2187 * This routine traverses a processes map handling the madvise 2188 * system call. Advisories are classified as either those effecting 2189 * the vm_map_entry structure, or those effecting the underlying 2190 * objects. 2191 * 2192 * The <value> argument is used for extended madvise calls. 2193 * 2194 * No requirements. 2195 */ 2196 int 2197 vm_map_madvise(vm_map_t map, vm_offset_t start, vm_offset_t end, 2198 int behav, off_t value) 2199 { 2200 vm_map_entry_t current, entry; 2201 int modify_map = 0; 2202 int error = 0; 2203 int count; 2204 2205 /* 2206 * Some madvise calls directly modify the vm_map_entry, in which case 2207 * we need to use an exclusive lock on the map and we need to perform 2208 * various clipping operations. Otherwise we only need a read-lock 2209 * on the map. 2210 */ 2211 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2212 2213 switch(behav) { 2214 case MADV_NORMAL: 2215 case MADV_SEQUENTIAL: 2216 case MADV_RANDOM: 2217 case MADV_NOSYNC: 2218 case MADV_AUTOSYNC: 2219 case MADV_NOCORE: 2220 case MADV_CORE: 2221 case MADV_SETMAP: 2222 modify_map = 1; 2223 vm_map_lock(map); 2224 break; 2225 case MADV_INVAL: 2226 case MADV_WILLNEED: 2227 case MADV_DONTNEED: 2228 case MADV_FREE: 2229 vm_map_lock_read(map); 2230 break; 2231 default: 2232 vm_map_entry_release(count); 2233 return (EINVAL); 2234 } 2235 2236 /* 2237 * Locate starting entry and clip if necessary. 2238 */ 2239 2240 VM_MAP_RANGE_CHECK(map, start, end); 2241 2242 if (vm_map_lookup_entry(map, start, &entry)) { 2243 if (modify_map) 2244 vm_map_clip_start(map, entry, start, &count); 2245 } else if (entry) { 2246 entry = vm_map_rb_tree_RB_NEXT(entry); 2247 } else { 2248 entry = RB_MIN(vm_map_rb_tree, &map->rb_root); 2249 } 2250 2251 if (modify_map) { 2252 /* 2253 * madvise behaviors that are implemented in the vm_map_entry. 2254 * 2255 * We clip the vm_map_entry so that behavioral changes are 2256 * limited to the specified address range. 2257 */ 2258 for (current = entry; 2259 current && current->ba.start < end; 2260 current = vm_map_rb_tree_RB_NEXT(current)) { 2261 /* 2262 * Ignore submaps 2263 */ 2264 if (current->maptype == VM_MAPTYPE_SUBMAP) 2265 continue; 2266 2267 vm_map_clip_end(map, current, end, &count); 2268 2269 switch (behav) { 2270 case MADV_NORMAL: 2271 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); 2272 break; 2273 case MADV_SEQUENTIAL: 2274 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); 2275 break; 2276 case MADV_RANDOM: 2277 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); 2278 break; 2279 case MADV_NOSYNC: 2280 current->eflags |= MAP_ENTRY_NOSYNC; 2281 break; 2282 case MADV_AUTOSYNC: 2283 current->eflags &= ~MAP_ENTRY_NOSYNC; 2284 break; 2285 case MADV_NOCORE: 2286 current->eflags |= MAP_ENTRY_NOCOREDUMP; 2287 break; 2288 case MADV_CORE: 2289 current->eflags &= ~MAP_ENTRY_NOCOREDUMP; 2290 break; 2291 case MADV_SETMAP: 2292 /* 2293 * Set the page directory page for a map 2294 * governed by a virtual page table. Mark 2295 * the entry as being governed by a virtual 2296 * page table if it is not. 2297 * 2298 * XXX the page directory page is stored 2299 * in the avail_ssize field if the map_entry. 2300 * 2301 * XXX the map simplification code does not 2302 * compare this field so weird things may 2303 * happen if you do not apply this function 2304 * to the entire mapping governed by the 2305 * virtual page table. 2306 */ 2307 if (current->maptype != VM_MAPTYPE_VPAGETABLE) { 2308 error = EINVAL; 2309 break; 2310 } 2311 current->aux.master_pde = value; 2312 pmap_remove(map->pmap, 2313 current->ba.start, current->ba.end); 2314 break; 2315 case MADV_INVAL: 2316 /* 2317 * Invalidate the related pmap entries, used 2318 * to flush portions of the real kernel's 2319 * pmap when the caller has removed or 2320 * modified existing mappings in a virtual 2321 * page table. 2322 * 2323 * (exclusive locked map version does not 2324 * need the range interlock). 2325 */ 2326 pmap_remove(map->pmap, 2327 current->ba.start, current->ba.end); 2328 break; 2329 default: 2330 error = EINVAL; 2331 break; 2332 } 2333 vm_map_simplify_entry(map, current, &count); 2334 } 2335 vm_map_unlock(map); 2336 } else { 2337 vm_pindex_t pindex; 2338 vm_pindex_t delta; 2339 2340 /* 2341 * madvise behaviors that are implemented in the underlying 2342 * vm_object. 2343 * 2344 * Since we don't clip the vm_map_entry, we have to clip 2345 * the vm_object pindex and count. 2346 * 2347 * NOTE! These functions are only supported on normal maps, 2348 * except MADV_INVAL which is also supported on 2349 * virtual page tables. 2350 * 2351 * NOTE! These functions only apply to the top-most object. 2352 * It is not applicable to backing objects. 2353 */ 2354 for (current = entry; 2355 current && current->ba.start < end; 2356 current = vm_map_rb_tree_RB_NEXT(current)) { 2357 vm_offset_t useStart; 2358 2359 if (current->maptype != VM_MAPTYPE_NORMAL && 2360 (current->maptype != VM_MAPTYPE_VPAGETABLE || 2361 behav != MADV_INVAL)) { 2362 continue; 2363 } 2364 2365 pindex = OFF_TO_IDX(current->ba.offset); 2366 delta = atop(current->ba.end - current->ba.start); 2367 useStart = current->ba.start; 2368 2369 if (current->ba.start < start) { 2370 pindex += atop(start - current->ba.start); 2371 delta -= atop(start - current->ba.start); 2372 useStart = start; 2373 } 2374 if (current->ba.end > end) 2375 delta -= atop(current->ba.end - end); 2376 2377 if ((vm_spindex_t)delta <= 0) 2378 continue; 2379 2380 if (behav == MADV_INVAL) { 2381 /* 2382 * Invalidate the related pmap entries, used 2383 * to flush portions of the real kernel's 2384 * pmap when the caller has removed or 2385 * modified existing mappings in a virtual 2386 * page table. 2387 * 2388 * (shared locked map version needs the 2389 * interlock, see vm_fault()). 2390 */ 2391 struct vm_map_ilock ilock; 2392 2393 KASSERT(useStart >= VM_MIN_USER_ADDRESS && 2394 useStart + ptoa(delta) <= 2395 VM_MAX_USER_ADDRESS, 2396 ("Bad range %016jx-%016jx (%016jx)", 2397 useStart, useStart + ptoa(delta), 2398 delta)); 2399 vm_map_interlock(map, &ilock, 2400 useStart, 2401 useStart + ptoa(delta)); 2402 pmap_remove(map->pmap, 2403 useStart, 2404 useStart + ptoa(delta)); 2405 vm_map_deinterlock(map, &ilock); 2406 } else { 2407 vm_object_madvise(current->ba.object, 2408 pindex, delta, behav); 2409 } 2410 2411 /* 2412 * Try to populate the page table. Mappings governed 2413 * by virtual page tables cannot be pre-populated 2414 * without a lot of work so don't try. 2415 */ 2416 if (behav == MADV_WILLNEED && 2417 current->maptype != VM_MAPTYPE_VPAGETABLE) { 2418 pmap_object_init_pt( 2419 map->pmap, current, 2420 useStart, 2421 (delta << PAGE_SHIFT), 2422 MAP_PREFAULT_MADVISE 2423 ); 2424 } 2425 } 2426 vm_map_unlock_read(map); 2427 } 2428 vm_map_entry_release(count); 2429 return(error); 2430 } 2431 2432 2433 /* 2434 * Sets the inheritance of the specified address range in the target map. 2435 * Inheritance affects how the map will be shared with child maps at the 2436 * time of vm_map_fork. 2437 */ 2438 int 2439 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, 2440 vm_inherit_t new_inheritance) 2441 { 2442 vm_map_entry_t entry; 2443 vm_map_entry_t temp_entry; 2444 int count; 2445 2446 switch (new_inheritance) { 2447 case VM_INHERIT_NONE: 2448 case VM_INHERIT_COPY: 2449 case VM_INHERIT_SHARE: 2450 break; 2451 default: 2452 return (KERN_INVALID_ARGUMENT); 2453 } 2454 2455 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2456 vm_map_lock(map); 2457 2458 VM_MAP_RANGE_CHECK(map, start, end); 2459 2460 if (vm_map_lookup_entry(map, start, &temp_entry)) { 2461 entry = temp_entry; 2462 vm_map_clip_start(map, entry, start, &count); 2463 } else if (temp_entry) { 2464 entry = vm_map_rb_tree_RB_NEXT(temp_entry); 2465 } else { 2466 entry = RB_MIN(vm_map_rb_tree, &map->rb_root); 2467 } 2468 2469 while (entry && entry->ba.start < end) { 2470 vm_map_clip_end(map, entry, end, &count); 2471 2472 entry->inheritance = new_inheritance; 2473 2474 vm_map_simplify_entry(map, entry, &count); 2475 2476 entry = vm_map_rb_tree_RB_NEXT(entry); 2477 } 2478 vm_map_unlock(map); 2479 vm_map_entry_release(count); 2480 return (KERN_SUCCESS); 2481 } 2482 2483 /* 2484 * Implement the semantics of mlock 2485 */ 2486 int 2487 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, 2488 boolean_t new_pageable) 2489 { 2490 vm_map_entry_t entry; 2491 vm_map_entry_t start_entry; 2492 vm_offset_t end; 2493 int rv = KERN_SUCCESS; 2494 int count; 2495 2496 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2497 vm_map_lock(map); 2498 VM_MAP_RANGE_CHECK(map, start, real_end); 2499 end = real_end; 2500 2501 start_entry = vm_map_clip_range(map, start, end, &count, 2502 MAP_CLIP_NO_HOLES); 2503 if (start_entry == NULL) { 2504 vm_map_unlock(map); 2505 vm_map_entry_release(count); 2506 return (KERN_INVALID_ADDRESS); 2507 } 2508 2509 if (new_pageable == 0) { 2510 entry = start_entry; 2511 while (entry && entry->ba.start < end) { 2512 vm_offset_t save_start; 2513 vm_offset_t save_end; 2514 2515 /* 2516 * Already user wired or hard wired (trivial cases) 2517 */ 2518 if (entry->eflags & MAP_ENTRY_USER_WIRED) { 2519 entry = vm_map_rb_tree_RB_NEXT(entry); 2520 continue; 2521 } 2522 if (entry->wired_count != 0) { 2523 entry->wired_count++; 2524 entry->eflags |= MAP_ENTRY_USER_WIRED; 2525 entry = vm_map_rb_tree_RB_NEXT(entry); 2526 continue; 2527 } 2528 2529 /* 2530 * A new wiring requires instantiation of appropriate 2531 * management structures and the faulting in of the 2532 * page. 2533 */ 2534 if (entry->maptype == VM_MAPTYPE_NORMAL || 2535 entry->maptype == VM_MAPTYPE_VPAGETABLE) { 2536 int copyflag = entry->eflags & 2537 MAP_ENTRY_NEEDS_COPY; 2538 if (copyflag && ((entry->protection & 2539 VM_PROT_WRITE) != 0)) { 2540 vm_map_entry_shadow(entry); 2541 } else if (entry->ba.object == NULL && 2542 !map->system_map) { 2543 vm_map_entry_allocate_object(entry); 2544 } 2545 } 2546 entry->wired_count++; 2547 entry->eflags |= MAP_ENTRY_USER_WIRED; 2548 2549 /* 2550 * Now fault in the area. Note that vm_fault_wire() 2551 * may release the map lock temporarily, it will be 2552 * relocked on return. The in-transition 2553 * flag protects the entries. 2554 */ 2555 save_start = entry->ba.start; 2556 save_end = entry->ba.end; 2557 rv = vm_fault_wire(map, entry, TRUE, 0); 2558 if (rv) { 2559 CLIP_CHECK_BACK(entry, save_start); 2560 for (;;) { 2561 KASSERT(entry->wired_count == 1, ("bad wired_count on entry")); 2562 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2563 entry->wired_count = 0; 2564 if (entry->ba.end == save_end) 2565 break; 2566 entry = vm_map_rb_tree_RB_NEXT(entry); 2567 KASSERT(entry, 2568 ("bad entry clip during backout")); 2569 } 2570 end = save_start; /* unwire the rest */ 2571 break; 2572 } 2573 /* 2574 * note that even though the entry might have been 2575 * clipped, the USER_WIRED flag we set prevents 2576 * duplication so we do not have to do a 2577 * clip check. 2578 */ 2579 entry = vm_map_rb_tree_RB_NEXT(entry); 2580 } 2581 2582 /* 2583 * If we failed fall through to the unwiring section to 2584 * unwire what we had wired so far. 'end' has already 2585 * been adjusted. 2586 */ 2587 if (rv) 2588 new_pageable = 1; 2589 2590 /* 2591 * start_entry might have been clipped if we unlocked the 2592 * map and blocked. No matter how clipped it has gotten 2593 * there should be a fragment that is on our start boundary. 2594 */ 2595 CLIP_CHECK_BACK(start_entry, start); 2596 } 2597 2598 /* 2599 * Deal with the unwiring case. 2600 */ 2601 if (new_pageable) { 2602 /* 2603 * This is the unwiring case. We must first ensure that the 2604 * range to be unwired is really wired down. We know there 2605 * are no holes. 2606 */ 2607 entry = start_entry; 2608 while (entry && entry->ba.start < end) { 2609 if ((entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { 2610 rv = KERN_INVALID_ARGUMENT; 2611 goto done; 2612 } 2613 KASSERT(entry->wired_count != 0, 2614 ("wired count was 0 with USER_WIRED set! %p", 2615 entry)); 2616 entry = vm_map_rb_tree_RB_NEXT(entry); 2617 } 2618 2619 /* 2620 * Now decrement the wiring count for each region. If a region 2621 * becomes completely unwired, unwire its physical pages and 2622 * mappings. 2623 */ 2624 /* 2625 * The map entries are processed in a loop, checking to 2626 * make sure the entry is wired and asserting it has a wired 2627 * count. However, another loop was inserted more-or-less in 2628 * the middle of the unwiring path. This loop picks up the 2629 * "entry" loop variable from the first loop without first 2630 * setting it to start_entry. Naturally, the secound loop 2631 * is never entered and the pages backing the entries are 2632 * never unwired. This can lead to a leak of wired pages. 2633 */ 2634 entry = start_entry; 2635 while (entry && entry->ba.start < end) { 2636 KASSERT(entry->eflags & MAP_ENTRY_USER_WIRED, 2637 ("expected USER_WIRED on entry %p", entry)); 2638 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 2639 entry->wired_count--; 2640 if (entry->wired_count == 0) 2641 vm_fault_unwire(map, entry); 2642 entry = vm_map_rb_tree_RB_NEXT(entry); 2643 } 2644 } 2645 done: 2646 vm_map_unclip_range(map, start_entry, start, real_end, &count, 2647 MAP_CLIP_NO_HOLES); 2648 vm_map_unlock(map); 2649 vm_map_entry_release(count); 2650 2651 return (rv); 2652 } 2653 2654 /* 2655 * Sets the pageability of the specified address range in the target map. 2656 * Regions specified as not pageable require locked-down physical 2657 * memory and physical page maps. 2658 * 2659 * The map must not be locked, but a reference must remain to the map 2660 * throughout the call. 2661 * 2662 * This function may be called via the zalloc path and must properly 2663 * reserve map entries for kernel_map. 2664 * 2665 * No requirements. 2666 */ 2667 int 2668 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, int kmflags) 2669 { 2670 vm_map_entry_t entry; 2671 vm_map_entry_t start_entry; 2672 vm_offset_t end; 2673 int rv = KERN_SUCCESS; 2674 int count; 2675 2676 if (kmflags & KM_KRESERVE) 2677 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); 2678 else 2679 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 2680 vm_map_lock(map); 2681 VM_MAP_RANGE_CHECK(map, start, real_end); 2682 end = real_end; 2683 2684 start_entry = vm_map_clip_range(map, start, end, &count, 2685 MAP_CLIP_NO_HOLES); 2686 if (start_entry == NULL) { 2687 vm_map_unlock(map); 2688 rv = KERN_INVALID_ADDRESS; 2689 goto failure; 2690 } 2691 if ((kmflags & KM_PAGEABLE) == 0) { 2692 /* 2693 * Wiring. 2694 * 2695 * 1. Holding the write lock, we create any shadow or zero-fill 2696 * objects that need to be created. Then we clip each map 2697 * entry to the region to be wired and increment its wiring 2698 * count. We create objects before clipping the map entries 2699 * to avoid object proliferation. 2700 * 2701 * 2. We downgrade to a read lock, and call vm_fault_wire to 2702 * fault in the pages for any newly wired area (wired_count is 2703 * 1). 2704 * 2705 * Downgrading to a read lock for vm_fault_wire avoids a 2706 * possible deadlock with another process that may have faulted 2707 * on one of the pages to be wired (it would mark the page busy, 2708 * blocking us, then in turn block on the map lock that we 2709 * hold). Because of problems in the recursive lock package, 2710 * we cannot upgrade to a write lock in vm_map_lookup. Thus, 2711 * any actions that require the write lock must be done 2712 * beforehand. Because we keep the read lock on the map, the 2713 * copy-on-write status of the entries we modify here cannot 2714 * change. 2715 */ 2716 entry = start_entry; 2717 while (entry && entry->ba.start < end) { 2718 /* 2719 * Trivial case if the entry is already wired 2720 */ 2721 if (entry->wired_count) { 2722 entry->wired_count++; 2723 entry = vm_map_rb_tree_RB_NEXT(entry); 2724 continue; 2725 } 2726 2727 /* 2728 * The entry is being newly wired, we have to setup 2729 * appropriate management structures. A shadow 2730 * object is required for a copy-on-write region, 2731 * or a normal object for a zero-fill region. We 2732 * do not have to do this for entries that point to sub 2733 * maps because we won't hold the lock on the sub map. 2734 */ 2735 if (entry->maptype == VM_MAPTYPE_NORMAL || 2736 entry->maptype == VM_MAPTYPE_VPAGETABLE) { 2737 int copyflag = entry->eflags & 2738 MAP_ENTRY_NEEDS_COPY; 2739 if (copyflag && ((entry->protection & 2740 VM_PROT_WRITE) != 0)) { 2741 vm_map_entry_shadow(entry); 2742 } else if (entry->ba.object == NULL && 2743 !map->system_map) { 2744 vm_map_entry_allocate_object(entry); 2745 } 2746 } 2747 entry->wired_count++; 2748 entry = vm_map_rb_tree_RB_NEXT(entry); 2749 } 2750 2751 /* 2752 * Pass 2. 2753 */ 2754 2755 /* 2756 * HACK HACK HACK HACK 2757 * 2758 * vm_fault_wire() temporarily unlocks the map to avoid 2759 * deadlocks. The in-transition flag from vm_map_clip_range 2760 * call should protect us from changes while the map is 2761 * unlocked. T 2762 * 2763 * NOTE: Previously this comment stated that clipping might 2764 * still occur while the entry is unlocked, but from 2765 * what I can tell it actually cannot. 2766 * 2767 * It is unclear whether the CLIP_CHECK_*() calls 2768 * are still needed but we keep them in anyway. 2769 * 2770 * HACK HACK HACK HACK 2771 */ 2772 2773 entry = start_entry; 2774 while (entry && entry->ba.start < end) { 2775 /* 2776 * If vm_fault_wire fails for any page we need to undo 2777 * what has been done. We decrement the wiring count 2778 * for those pages which have not yet been wired (now) 2779 * and unwire those that have (later). 2780 */ 2781 vm_offset_t save_start = entry->ba.start; 2782 vm_offset_t save_end = entry->ba.end; 2783 2784 if (entry->wired_count == 1) 2785 rv = vm_fault_wire(map, entry, FALSE, kmflags); 2786 if (rv) { 2787 CLIP_CHECK_BACK(entry, save_start); 2788 for (;;) { 2789 KASSERT(entry->wired_count == 1, 2790 ("wired_count changed unexpectedly")); 2791 entry->wired_count = 0; 2792 if (entry->ba.end == save_end) 2793 break; 2794 entry = vm_map_rb_tree_RB_NEXT(entry); 2795 KASSERT(entry, 2796 ("bad entry clip during backout")); 2797 } 2798 end = save_start; 2799 break; 2800 } 2801 CLIP_CHECK_FWD(entry, save_end); 2802 entry = vm_map_rb_tree_RB_NEXT(entry); 2803 } 2804 2805 /* 2806 * If a failure occured undo everything by falling through 2807 * to the unwiring code. 'end' has already been adjusted 2808 * appropriately. 2809 */ 2810 if (rv) 2811 kmflags |= KM_PAGEABLE; 2812 2813 /* 2814 * start_entry is still IN_TRANSITION but may have been 2815 * clipped since vm_fault_wire() unlocks and relocks the 2816 * map. No matter how clipped it has gotten there should 2817 * be a fragment that is on our start boundary. 2818 */ 2819 CLIP_CHECK_BACK(start_entry, start); 2820 } 2821 2822 if (kmflags & KM_PAGEABLE) { 2823 /* 2824 * This is the unwiring case. We must first ensure that the 2825 * range to be unwired is really wired down. We know there 2826 * are no holes. 2827 */ 2828 entry = start_entry; 2829 while (entry && entry->ba.start < end) { 2830 if (entry->wired_count == 0) { 2831 rv = KERN_INVALID_ARGUMENT; 2832 goto done; 2833 } 2834 entry = vm_map_rb_tree_RB_NEXT(entry); 2835 } 2836 2837 /* 2838 * Now decrement the wiring count for each region. If a region 2839 * becomes completely unwired, unwire its physical pages and 2840 * mappings. 2841 */ 2842 entry = start_entry; 2843 while (entry && entry->ba.start < end) { 2844 entry->wired_count--; 2845 if (entry->wired_count == 0) 2846 vm_fault_unwire(map, entry); 2847 entry = vm_map_rb_tree_RB_NEXT(entry); 2848 } 2849 } 2850 done: 2851 vm_map_unclip_range(map, start_entry, start, real_end, 2852 &count, MAP_CLIP_NO_HOLES); 2853 vm_map_unlock(map); 2854 failure: 2855 if (kmflags & KM_KRESERVE) 2856 vm_map_entry_krelease(count); 2857 else 2858 vm_map_entry_release(count); 2859 return (rv); 2860 } 2861 2862 /* 2863 * Mark a newly allocated address range as wired but do not fault in 2864 * the pages. The caller is expected to load the pages into the object. 2865 * 2866 * The map must be locked on entry and will remain locked on return. 2867 * No other requirements. 2868 */ 2869 void 2870 vm_map_set_wired_quick(vm_map_t map, vm_offset_t addr, vm_size_t size, 2871 int *countp) 2872 { 2873 vm_map_entry_t scan; 2874 vm_map_entry_t entry; 2875 2876 entry = vm_map_clip_range(map, addr, addr + size, 2877 countp, MAP_CLIP_NO_HOLES); 2878 scan = entry; 2879 while (scan && scan->ba.start < addr + size) { 2880 KKASSERT(scan->wired_count == 0); 2881 scan->wired_count = 1; 2882 scan = vm_map_rb_tree_RB_NEXT(scan); 2883 } 2884 vm_map_unclip_range(map, entry, addr, addr + size, 2885 countp, MAP_CLIP_NO_HOLES); 2886 } 2887 2888 /* 2889 * Push any dirty cached pages in the address range to their pager. 2890 * If syncio is TRUE, dirty pages are written synchronously. 2891 * If invalidate is TRUE, any cached pages are freed as well. 2892 * 2893 * This routine is called by sys_msync() 2894 * 2895 * Returns an error if any part of the specified range is not mapped. 2896 * 2897 * No requirements. 2898 */ 2899 int 2900 vm_map_clean(vm_map_t map, vm_offset_t start, vm_offset_t end, 2901 boolean_t syncio, boolean_t invalidate) 2902 { 2903 vm_map_entry_t current; 2904 vm_map_entry_t next; 2905 vm_map_entry_t entry; 2906 vm_map_backing_t ba; 2907 vm_size_t size; 2908 vm_object_t object; 2909 vm_ooffset_t offset; 2910 2911 vm_map_lock_read(map); 2912 VM_MAP_RANGE_CHECK(map, start, end); 2913 if (!vm_map_lookup_entry(map, start, &entry)) { 2914 vm_map_unlock_read(map); 2915 return (KERN_INVALID_ADDRESS); 2916 } 2917 lwkt_gettoken(&map->token); 2918 2919 /* 2920 * Make a first pass to check for holes. 2921 */ 2922 current = entry; 2923 while (current && current->ba.start < end) { 2924 if (current->maptype == VM_MAPTYPE_SUBMAP) { 2925 lwkt_reltoken(&map->token); 2926 vm_map_unlock_read(map); 2927 return (KERN_INVALID_ARGUMENT); 2928 } 2929 next = vm_map_rb_tree_RB_NEXT(current); 2930 if (end > current->ba.end && 2931 (next == NULL || 2932 current->ba.end != next->ba.start)) { 2933 lwkt_reltoken(&map->token); 2934 vm_map_unlock_read(map); 2935 return (KERN_INVALID_ADDRESS); 2936 } 2937 current = next; 2938 } 2939 2940 if (invalidate) 2941 pmap_remove(vm_map_pmap(map), start, end); 2942 2943 /* 2944 * Make a second pass, cleaning/uncaching pages from the indicated 2945 * objects as we go. 2946 */ 2947 current = entry; 2948 while (current && current->ba.start < end) { 2949 offset = current->ba.offset + (start - current->ba.start); 2950 size = (end <= current->ba.end ? end : current->ba.end) - start; 2951 2952 switch(current->maptype) { 2953 case VM_MAPTYPE_SUBMAP: 2954 { 2955 vm_map_t smap; 2956 vm_map_entry_t tentry; 2957 vm_size_t tsize; 2958 2959 smap = current->ba.sub_map; 2960 vm_map_lock_read(smap); 2961 vm_map_lookup_entry(smap, offset, &tentry); 2962 if (tentry == NULL) { 2963 tsize = vm_map_max(smap) - offset; 2964 ba = NULL; 2965 offset = 0 + (offset - vm_map_min(smap)); 2966 } else { 2967 tsize = tentry->ba.end - offset; 2968 ba = &tentry->ba; 2969 offset = tentry->ba.offset + 2970 (offset - tentry->ba.start); 2971 } 2972 vm_map_unlock_read(smap); 2973 if (tsize < size) 2974 size = tsize; 2975 break; 2976 } 2977 case VM_MAPTYPE_NORMAL: 2978 case VM_MAPTYPE_VPAGETABLE: 2979 ba = ¤t->ba; 2980 break; 2981 default: 2982 ba = NULL; 2983 break; 2984 } 2985 if (ba) { 2986 object = ba->object; 2987 if (object) 2988 vm_object_hold(object); 2989 } else { 2990 object = NULL; 2991 } 2992 2993 /* 2994 * Note that there is absolutely no sense in writing out 2995 * anonymous objects, so we track down the vnode object 2996 * to write out. 2997 * We invalidate (remove) all pages from the address space 2998 * anyway, for semantic correctness. 2999 * 3000 * note: certain anonymous maps, such as MAP_NOSYNC maps, 3001 * may start out with a NULL object. 3002 * 3003 * XXX do we really want to stop at the first backing store 3004 * here if there are more? XXX 3005 */ 3006 if (ba) { 3007 vm_object_t tobj; 3008 3009 tobj = object; 3010 while (ba->backing_ba != NULL) { 3011 offset -= ba->offset; 3012 ba = ba->backing_ba; 3013 offset += ba->offset; 3014 tobj = ba->object; 3015 if (tobj->size < OFF_TO_IDX(offset + size)) 3016 size = IDX_TO_OFF(tobj->size) - offset; 3017 break; /* XXX this break is not correct */ 3018 } 3019 if (object != tobj) { 3020 if (object) 3021 vm_object_drop(object); 3022 object = tobj; 3023 vm_object_hold(object); 3024 } 3025 } 3026 3027 if (object && (object->type == OBJT_VNODE) && 3028 (current->protection & VM_PROT_WRITE) && 3029 (object->flags & OBJ_NOMSYNC) == 0) { 3030 /* 3031 * Flush pages if writing is allowed, invalidate them 3032 * if invalidation requested. Pages undergoing I/O 3033 * will be ignored by vm_object_page_remove(). 3034 * 3035 * We cannot lock the vnode and then wait for paging 3036 * to complete without deadlocking against vm_fault. 3037 * Instead we simply call vm_object_page_remove() and 3038 * allow it to block internally on a page-by-page 3039 * basis when it encounters pages undergoing async 3040 * I/O. 3041 */ 3042 int flags; 3043 3044 /* no chain wait needed for vnode objects */ 3045 vm_object_reference_locked(object); 3046 vn_lock(object->handle, LK_EXCLUSIVE | LK_RETRY); 3047 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 3048 flags |= invalidate ? OBJPC_INVAL : 0; 3049 3050 /* 3051 * When operating on a virtual page table just 3052 * flush the whole object. XXX we probably ought 3053 * to 3054 */ 3055 switch(current->maptype) { 3056 case VM_MAPTYPE_NORMAL: 3057 vm_object_page_clean(object, 3058 OFF_TO_IDX(offset), 3059 OFF_TO_IDX(offset + size + PAGE_MASK), 3060 flags); 3061 break; 3062 case VM_MAPTYPE_VPAGETABLE: 3063 vm_object_page_clean(object, 0, 0, flags); 3064 break; 3065 } 3066 vn_unlock(((struct vnode *)object->handle)); 3067 vm_object_deallocate_locked(object); 3068 } 3069 if (object && invalidate && 3070 ((object->type == OBJT_VNODE) || 3071 (object->type == OBJT_DEVICE) || 3072 (object->type == OBJT_MGTDEVICE))) { 3073 int clean_only = 3074 ((object->type == OBJT_DEVICE) || 3075 (object->type == OBJT_MGTDEVICE)) ? FALSE : TRUE; 3076 /* no chain wait needed for vnode/device objects */ 3077 vm_object_reference_locked(object); 3078 switch(current->maptype) { 3079 case VM_MAPTYPE_NORMAL: 3080 vm_object_page_remove(object, 3081 OFF_TO_IDX(offset), 3082 OFF_TO_IDX(offset + size + PAGE_MASK), 3083 clean_only); 3084 break; 3085 case VM_MAPTYPE_VPAGETABLE: 3086 vm_object_page_remove(object, 0, 0, clean_only); 3087 break; 3088 } 3089 vm_object_deallocate_locked(object); 3090 } 3091 start += size; 3092 if (object) 3093 vm_object_drop(object); 3094 current = vm_map_rb_tree_RB_NEXT(current); 3095 } 3096 3097 lwkt_reltoken(&map->token); 3098 vm_map_unlock_read(map); 3099 3100 return (KERN_SUCCESS); 3101 } 3102 3103 /* 3104 * Make the region specified by this entry pageable. 3105 * 3106 * The vm_map must be exclusively locked. 3107 */ 3108 static void 3109 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) 3110 { 3111 entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3112 entry->wired_count = 0; 3113 vm_fault_unwire(map, entry); 3114 } 3115 3116 /* 3117 * Deallocate the given entry from the target map. 3118 * 3119 * The vm_map must be exclusively locked. 3120 */ 3121 static void 3122 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry, int *countp) 3123 { 3124 vm_map_entry_unlink(map, entry); 3125 map->size -= entry->ba.end - entry->ba.start; 3126 vm_map_entry_dispose(map, entry, countp); 3127 } 3128 3129 /* 3130 * Deallocates the given address range from the target map. 3131 * 3132 * The vm_map must be exclusively locked. 3133 */ 3134 int 3135 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end, int *countp) 3136 { 3137 vm_object_t object; 3138 vm_map_entry_t entry; 3139 vm_map_entry_t first_entry; 3140 vm_offset_t hole_start; 3141 3142 ASSERT_VM_MAP_LOCKED(map); 3143 lwkt_gettoken(&map->token); 3144 again: 3145 /* 3146 * Find the start of the region, and clip it. Set entry to point 3147 * at the first record containing the requested address or, if no 3148 * such record exists, the next record with a greater address. The 3149 * loop will run from this point until a record beyond the termination 3150 * address is encountered. 3151 * 3152 * Adjust freehint[] for either the clip case or the extension case. 3153 * 3154 * GGG see other GGG comment. 3155 */ 3156 if (vm_map_lookup_entry(map, start, &first_entry)) { 3157 entry = first_entry; 3158 vm_map_clip_start(map, entry, start, countp); 3159 hole_start = start; 3160 } else { 3161 if (first_entry) { 3162 entry = vm_map_rb_tree_RB_NEXT(first_entry); 3163 if (entry == NULL) 3164 hole_start = first_entry->ba.start; 3165 else 3166 hole_start = first_entry->ba.end; 3167 } else { 3168 entry = RB_MIN(vm_map_rb_tree, &map->rb_root); 3169 if (entry == NULL) 3170 hole_start = vm_map_min(map); 3171 else 3172 hole_start = vm_map_max(map); 3173 } 3174 } 3175 3176 /* 3177 * Step through all entries in this region 3178 */ 3179 while (entry && entry->ba.start < end) { 3180 vm_map_entry_t next; 3181 vm_offset_t s, e; 3182 vm_pindex_t offidxstart, offidxend, count; 3183 3184 /* 3185 * If we hit an in-transition entry we have to sleep and 3186 * retry. It's easier (and not really slower) to just retry 3187 * since this case occurs so rarely and the hint is already 3188 * pointing at the right place. We have to reset the 3189 * start offset so as not to accidently delete an entry 3190 * another process just created in vacated space. 3191 */ 3192 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 3193 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 3194 start = entry->ba.start; 3195 ++mycpu->gd_cnt.v_intrans_coll; 3196 ++mycpu->gd_cnt.v_intrans_wait; 3197 vm_map_transition_wait(map, 1); 3198 goto again; 3199 } 3200 vm_map_clip_end(map, entry, end, countp); 3201 3202 s = entry->ba.start; 3203 e = entry->ba.end; 3204 next = vm_map_rb_tree_RB_NEXT(entry); 3205 3206 offidxstart = OFF_TO_IDX(entry->ba.offset); 3207 count = OFF_TO_IDX(e - s); 3208 3209 switch(entry->maptype) { 3210 case VM_MAPTYPE_NORMAL: 3211 case VM_MAPTYPE_VPAGETABLE: 3212 case VM_MAPTYPE_SUBMAP: 3213 object = entry->ba.object; 3214 break; 3215 default: 3216 object = NULL; 3217 break; 3218 } 3219 3220 /* 3221 * Unwire before removing addresses from the pmap; otherwise, 3222 * unwiring will put the entries back in the pmap. 3223 * 3224 * Generally speaking, doing a bulk pmap_remove() before 3225 * removing the pages from the VM object is better at 3226 * reducing unnecessary IPIs. The pmap code is now optimized 3227 * to not blindly iterate the range when pt and pd pages 3228 * are missing. 3229 */ 3230 if (entry->wired_count != 0) 3231 vm_map_entry_unwire(map, entry); 3232 3233 offidxend = offidxstart + count; 3234 3235 if (object == &kernel_object) { 3236 pmap_remove(map->pmap, s, e); 3237 vm_object_hold(object); 3238 vm_object_page_remove(object, offidxstart, 3239 offidxend, FALSE); 3240 vm_object_drop(object); 3241 } else if (object && object->type != OBJT_DEFAULT && 3242 object->type != OBJT_SWAP) { 3243 /* 3244 * vnode object routines cannot be chain-locked, 3245 * but since we aren't removing pages from the 3246 * object here we can use a shared hold. 3247 */ 3248 vm_object_hold_shared(object); 3249 pmap_remove(map->pmap, s, e); 3250 vm_object_drop(object); 3251 } else if (object) { 3252 vm_object_hold(object); 3253 pmap_remove(map->pmap, s, e); 3254 3255 if (object != NULL && 3256 object->ref_count != 1 && 3257 (object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == 3258 OBJ_ONEMAPPING && 3259 (object->type == OBJT_DEFAULT || 3260 object->type == OBJT_SWAP)) { 3261 /* 3262 * When ONEMAPPING is set we can destroy the 3263 * pages underlying the entry's range. 3264 */ 3265 vm_object_page_remove(object, offidxstart, 3266 offidxend, FALSE); 3267 if (object->type == OBJT_SWAP) { 3268 swap_pager_freespace(object, 3269 offidxstart, 3270 count); 3271 } 3272 if (offidxend >= object->size && 3273 offidxstart < object->size) { 3274 object->size = offidxstart; 3275 } 3276 } 3277 vm_object_drop(object); 3278 } else if (entry->maptype == VM_MAPTYPE_UKSMAP) { 3279 pmap_remove(map->pmap, s, e); 3280 } 3281 3282 /* 3283 * Delete the entry (which may delete the object) only after 3284 * removing all pmap entries pointing to its pages. 3285 * (Otherwise, its page frames may be reallocated, and any 3286 * modify bits will be set in the wrong object!) 3287 */ 3288 vm_map_entry_delete(map, entry, countp); 3289 entry = next; 3290 } 3291 3292 /* 3293 * We either reached the end and use vm_map_max as the end 3294 * address, or we didn't and we use the next entry as the 3295 * end address. 3296 */ 3297 if (entry == NULL) { 3298 vm_map_freehint_hole(map, hole_start, 3299 vm_map_max(map) - hole_start); 3300 } else { 3301 vm_map_freehint_hole(map, hole_start, 3302 entry->ba.start - hole_start); 3303 } 3304 3305 lwkt_reltoken(&map->token); 3306 3307 return (KERN_SUCCESS); 3308 } 3309 3310 /* 3311 * Remove the given address range from the target map. 3312 * This is the exported form of vm_map_delete. 3313 * 3314 * No requirements. 3315 */ 3316 int 3317 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) 3318 { 3319 int result; 3320 int count; 3321 3322 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3323 vm_map_lock(map); 3324 VM_MAP_RANGE_CHECK(map, start, end); 3325 result = vm_map_delete(map, start, end, &count); 3326 vm_map_unlock(map); 3327 vm_map_entry_release(count); 3328 3329 return (result); 3330 } 3331 3332 /* 3333 * Assert that the target map allows the specified privilege on the 3334 * entire address region given. The entire region must be allocated. 3335 * 3336 * The caller must specify whether the vm_map is already locked or not. 3337 */ 3338 boolean_t 3339 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, 3340 vm_prot_t protection, boolean_t have_lock) 3341 { 3342 vm_map_entry_t entry; 3343 vm_map_entry_t tmp_entry; 3344 boolean_t result; 3345 3346 if (have_lock == FALSE) 3347 vm_map_lock_read(map); 3348 3349 if (!vm_map_lookup_entry(map, start, &tmp_entry)) { 3350 if (have_lock == FALSE) 3351 vm_map_unlock_read(map); 3352 return (FALSE); 3353 } 3354 entry = tmp_entry; 3355 3356 result = TRUE; 3357 while (start < end) { 3358 if (entry == NULL) { 3359 result = FALSE; 3360 break; 3361 } 3362 3363 /* 3364 * No holes allowed! 3365 */ 3366 3367 if (start < entry->ba.start) { 3368 result = FALSE; 3369 break; 3370 } 3371 /* 3372 * Check protection associated with entry. 3373 */ 3374 3375 if ((entry->protection & protection) != protection) { 3376 result = FALSE; 3377 break; 3378 } 3379 /* go to next entry */ 3380 start = entry->ba.end; 3381 entry = vm_map_rb_tree_RB_NEXT(entry); 3382 } 3383 if (have_lock == FALSE) 3384 vm_map_unlock_read(map); 3385 return (result); 3386 } 3387 3388 /* 3389 * vm_map_backing structures are not shared across forks and must be 3390 * replicated. 3391 * 3392 * Generally speaking we must reallocate the backing_ba sequence and 3393 * also adjust it for any changes made to the base entry->ba.start and 3394 * entry->ba.end. The first ba in the chain is of course &entry->ba, 3395 * so we only need to adjust subsequent ba's start, end, and offset. 3396 * 3397 * MAP_BACK_CLIPPED - Called as part of a clipping replication. 3398 * Do not clear OBJ_ONEMAPPING. 3399 * 3400 * MAP_BACK_BASEOBJREFD - Called from vm_map_insert(). The base object 3401 * has already been referenced. 3402 */ 3403 static 3404 void 3405 vm_map_backing_replicated(vm_map_t map, vm_map_entry_t entry, int flags) 3406 { 3407 vm_map_backing_t ba; 3408 vm_map_backing_t nba; 3409 vm_object_t object; 3410 3411 ba = &entry->ba; 3412 for (;;) { 3413 object = ba->object; 3414 ba->pmap = map->pmap; 3415 if (object && 3416 (entry->maptype == VM_MAPTYPE_VPAGETABLE || 3417 entry->maptype == VM_MAPTYPE_NORMAL)) { 3418 if (ba != &entry->ba || 3419 (flags & MAP_BACK_BASEOBJREFD) == 0) { 3420 vm_object_reference_quick(object); 3421 } 3422 vm_map_backing_attach(ba); 3423 if ((flags & MAP_BACK_CLIPPED) == 0 && 3424 object->ref_count > 1) { 3425 vm_object_clear_flag(object, OBJ_ONEMAPPING); 3426 } 3427 } 3428 if (ba->backing_ba == NULL) 3429 break; 3430 nba = kmalloc(sizeof(*nba), M_MAP_BACKING, M_INTWAIT); 3431 *nba = *ba->backing_ba; 3432 nba->offset += (ba->start - nba->start); /* += (new - old) */ 3433 nba->start = ba->start; 3434 nba->end = ba->end; 3435 ba->backing_ba = nba; 3436 ba = nba; 3437 /* pmap is replaced at the top of the loop */ 3438 } 3439 } 3440 3441 static 3442 void 3443 vm_map_backing_adjust_start(vm_map_entry_t entry, vm_ooffset_t start) 3444 { 3445 vm_map_backing_t ba; 3446 3447 if (entry->maptype == VM_MAPTYPE_VPAGETABLE || 3448 entry->maptype == VM_MAPTYPE_NORMAL) { 3449 for (ba = &entry->ba; ba; ba = ba->backing_ba) { 3450 if (ba->object) { 3451 lockmgr(&ba->object->backing_lk, LK_EXCLUSIVE); 3452 ba->offset += (start - ba->start); 3453 ba->start = start; 3454 lockmgr(&ba->object->backing_lk, LK_RELEASE); 3455 } else { 3456 ba->offset += (start - ba->start); 3457 ba->start = start; 3458 } 3459 } 3460 } else { 3461 /* not an object and can't be shadowed */ 3462 } 3463 } 3464 3465 static 3466 void 3467 vm_map_backing_adjust_end(vm_map_entry_t entry, vm_ooffset_t end) 3468 { 3469 vm_map_backing_t ba; 3470 3471 if (entry->maptype == VM_MAPTYPE_VPAGETABLE || 3472 entry->maptype == VM_MAPTYPE_NORMAL) { 3473 for (ba = &entry->ba; ba; ba = ba->backing_ba) { 3474 if (ba->object) { 3475 lockmgr(&ba->object->backing_lk, LK_EXCLUSIVE); 3476 ba->end = end; 3477 lockmgr(&ba->object->backing_lk, LK_RELEASE); 3478 } else { 3479 ba->end = end; 3480 } 3481 } 3482 } else { 3483 /* not an object and can't be shadowed */ 3484 } 3485 } 3486 3487 /* 3488 * Handles the dirty work of making src_entry and dst_entry copy-on-write 3489 * after src_entry has been cloned to dst_entry. For normal entries only. 3490 * 3491 * The vm_maps must be exclusively locked. 3492 * The vm_map's token must be held. 3493 * 3494 * Because the maps are locked no faults can be in progress during the 3495 * operation. 3496 */ 3497 static void 3498 vm_map_copy_entry(vm_map_t src_map, vm_map_t dst_map, 3499 vm_map_entry_t src_entry, vm_map_entry_t dst_entry) 3500 { 3501 vm_object_t obj; 3502 3503 KKASSERT(dst_entry->maptype == VM_MAPTYPE_NORMAL || 3504 dst_entry->maptype == VM_MAPTYPE_VPAGETABLE); 3505 3506 if (src_entry->wired_count && 3507 src_entry->maptype != VM_MAPTYPE_VPAGETABLE) { 3508 /* 3509 * Of course, wired down pages can't be set copy-on-write. 3510 * Cause wired pages to be copied into the new map by 3511 * simulating faults (the new pages are pageable) 3512 * 3513 * Scrap ba.object (its ref-count has not yet been adjusted 3514 * so we can just NULL out the field). Remove the backing 3515 * store. 3516 * 3517 * Then call vm_fault_copy_entry() to create a new object 3518 * in dst_entry and copy the wired pages from src to dst. 3519 * 3520 * The fault-copy code doesn't work with virtual page 3521 * tables. 3522 */ 3523 if ((obj = dst_entry->ba.object) != NULL) { 3524 vm_map_backing_detach(&dst_entry->ba); 3525 dst_entry->ba.object = NULL; 3526 vm_map_entry_dispose_ba(dst_entry->ba.backing_ba); 3527 dst_entry->ba.backing_ba = NULL; 3528 dst_entry->ba.backing_count = 0; 3529 } 3530 vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry); 3531 } else { 3532 if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) { 3533 /* 3534 * If the source entry is not already marked NEEDS_COPY 3535 * we need to write-protect the PTEs. 3536 */ 3537 pmap_protect(src_map->pmap, 3538 src_entry->ba.start, 3539 src_entry->ba.end, 3540 src_entry->protection & ~VM_PROT_WRITE); 3541 } 3542 3543 /* 3544 * dst_entry.ba_object might be stale. Update it (its 3545 * ref-count has not yet been updated so just overwrite 3546 * the field). 3547 * 3548 * If there is no object then we are golden. Also, in 3549 * this situation if there are no backing_ba linkages then 3550 * we can set ba.offset to whatever we want. For now we 3551 * set the offset for 0 for make debugging object sizes 3552 * easier. 3553 */ 3554 obj = src_entry->ba.object; 3555 3556 if (obj) { 3557 src_entry->eflags |= (MAP_ENTRY_COW | 3558 MAP_ENTRY_NEEDS_COPY); 3559 dst_entry->eflags |= (MAP_ENTRY_COW | 3560 MAP_ENTRY_NEEDS_COPY); 3561 KKASSERT(dst_entry->ba.offset == src_entry->ba.offset); 3562 } else { 3563 dst_entry->ba.offset = 0; 3564 } 3565 3566 /* 3567 * Normal, allow the backing_ba link depth to 3568 * increase. 3569 */ 3570 pmap_copy(dst_map->pmap, src_map->pmap, 3571 dst_entry->ba.start, 3572 dst_entry->ba.end - dst_entry->ba.start, 3573 src_entry->ba.start); 3574 } 3575 } 3576 3577 /* 3578 * Create a vmspace for a new process and its related vm_map based on an 3579 * existing vmspace. The new map inherits information from the old map 3580 * according to inheritance settings. 3581 * 3582 * The source map must not be locked. 3583 * No requirements. 3584 */ 3585 static void vmspace_fork_normal_entry(vm_map_t old_map, vm_map_t new_map, 3586 vm_map_entry_t old_entry, int *countp); 3587 static void vmspace_fork_uksmap_entry(vm_map_t old_map, vm_map_t new_map, 3588 vm_map_entry_t old_entry, int *countp); 3589 3590 struct vmspace * 3591 vmspace_fork(struct vmspace *vm1) 3592 { 3593 struct vmspace *vm2; 3594 vm_map_t old_map = &vm1->vm_map; 3595 vm_map_t new_map; 3596 vm_map_entry_t old_entry; 3597 int count; 3598 3599 lwkt_gettoken(&vm1->vm_map.token); 3600 vm_map_lock(old_map); 3601 3602 vm2 = vmspace_alloc(vm_map_min(old_map), vm_map_max(old_map)); 3603 lwkt_gettoken(&vm2->vm_map.token); 3604 3605 /* 3606 * We must bump the timestamp to force any concurrent fault 3607 * to retry. 3608 */ 3609 bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy, 3610 (caddr_t)&vm1->vm_endcopy - (caddr_t)&vm1->vm_startcopy); 3611 new_map = &vm2->vm_map; /* XXX */ 3612 new_map->timestamp = 1; 3613 3614 vm_map_lock(new_map); 3615 3616 count = old_map->nentries; 3617 count = vm_map_entry_reserve(count + MAP_RESERVE_COUNT); 3618 3619 RB_FOREACH(old_entry, vm_map_rb_tree, &old_map->rb_root) { 3620 switch(old_entry->maptype) { 3621 case VM_MAPTYPE_SUBMAP: 3622 panic("vm_map_fork: encountered a submap"); 3623 break; 3624 case VM_MAPTYPE_UKSMAP: 3625 vmspace_fork_uksmap_entry(old_map, new_map, 3626 old_entry, &count); 3627 break; 3628 case VM_MAPTYPE_NORMAL: 3629 case VM_MAPTYPE_VPAGETABLE: 3630 vmspace_fork_normal_entry(old_map, new_map, 3631 old_entry, &count); 3632 break; 3633 } 3634 } 3635 3636 new_map->size = old_map->size; 3637 vm_map_unlock(new_map); 3638 vm_map_unlock(old_map); 3639 vm_map_entry_release(count); 3640 3641 lwkt_reltoken(&vm2->vm_map.token); 3642 lwkt_reltoken(&vm1->vm_map.token); 3643 3644 return (vm2); 3645 } 3646 3647 static 3648 void 3649 vmspace_fork_normal_entry(vm_map_t old_map, vm_map_t new_map, 3650 vm_map_entry_t old_entry, int *countp) 3651 { 3652 vm_map_entry_t new_entry; 3653 vm_map_backing_t ba; 3654 vm_object_t object; 3655 3656 /* 3657 * If the backing_ba link list gets too long then fault it 3658 * all into the head object and dispose of the list. We do 3659 * this in old_entry prior to cloning in order to benefit both 3660 * parent and child. 3661 * 3662 * We can test our fronting object's size against its 3663 * resident_page_count for a really cheap (but probably not perfect) 3664 * all-shadowed test, allowing us to disconnect the backing_ba 3665 * link list early. 3666 * 3667 * XXX Currently doesn't work for VPAGETABLEs (the entire object 3668 * would have to be copied). 3669 */ 3670 object = old_entry->ba.object; 3671 if (old_entry->ba.backing_ba && 3672 old_entry->maptype != VM_MAPTYPE_VPAGETABLE && 3673 (old_entry->ba.backing_count >= vm_map_backing_limit || 3674 (vm_map_backing_shadow_test && object && 3675 object->size == object->resident_page_count))) { 3676 /* 3677 * If there are too many backing_ba linkages we 3678 * collapse everything into the head 3679 * 3680 * This will also remove all the pte's. 3681 */ 3682 if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) 3683 vm_map_entry_shadow(old_entry); 3684 if (object == NULL) 3685 vm_map_entry_allocate_object(old_entry); 3686 if (vm_fault_collapse(old_map, old_entry) == KERN_SUCCESS) { 3687 ba = old_entry->ba.backing_ba; 3688 old_entry->ba.backing_ba = NULL; 3689 old_entry->ba.backing_count = 0; 3690 vm_map_entry_dispose_ba(ba); 3691 } 3692 } 3693 object = NULL; /* object variable is now invalid */ 3694 3695 /* 3696 * Fork the entry 3697 */ 3698 switch (old_entry->inheritance) { 3699 case VM_INHERIT_NONE: 3700 break; 3701 case VM_INHERIT_SHARE: 3702 /* 3703 * Clone the entry as a shared entry. This will look like 3704 * shared memory across the old and the new process. We must 3705 * ensure that the object is allocated. 3706 */ 3707 if (old_entry->ba.object == NULL) 3708 vm_map_entry_allocate_object(old_entry); 3709 3710 if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { 3711 /* 3712 * Create the fronting vm_map_backing for 3713 * an entry which needs a copy, plus an extra 3714 * ref because we are going to duplicate it 3715 * in the fork. 3716 * 3717 * The call to vm_map_entry_shadow() will also clear 3718 * OBJ_ONEMAPPING. 3719 * 3720 * XXX no more collapse. Still need extra ref 3721 * for the fork. 3722 */ 3723 vm_map_entry_shadow(old_entry); 3724 } else if (old_entry->ba.object) { 3725 object = old_entry->ba.object; 3726 } 3727 3728 /* 3729 * Clone the entry. We've already bumped the ref on 3730 * the vm_object for our new entry. 3731 */ 3732 new_entry = vm_map_entry_create(countp); 3733 *new_entry = *old_entry; 3734 3735 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3736 new_entry->wired_count = 0; 3737 3738 /* 3739 * Replicate and index the vm_map_backing. Don't share 3740 * the vm_map_backing across vm_map's (only across clips). 3741 * 3742 * Insert the entry into the new map -- we know we're 3743 * inserting at the end of the new map. 3744 */ 3745 vm_map_backing_replicated(new_map, new_entry, 0); 3746 vm_map_entry_link(new_map, new_entry); 3747 3748 /* 3749 * Update the physical map 3750 */ 3751 pmap_copy(new_map->pmap, old_map->pmap, 3752 new_entry->ba.start, 3753 (old_entry->ba.end - old_entry->ba.start), 3754 old_entry->ba.start); 3755 break; 3756 case VM_INHERIT_COPY: 3757 /* 3758 * Clone the entry and link the copy into the new map. 3759 * 3760 * Note that ref-counting adjustment for old_entry->ba.object 3761 * (if it isn't a special map that is) is handled by 3762 * vm_map_copy_entry(). 3763 */ 3764 new_entry = vm_map_entry_create(countp); 3765 *new_entry = *old_entry; 3766 3767 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3768 new_entry->wired_count = 0; 3769 3770 vm_map_backing_replicated(new_map, new_entry, 0); 3771 vm_map_entry_link(new_map, new_entry); 3772 3773 /* 3774 * This does the actual dirty work of making both entries 3775 * copy-on-write, and will also handle the fronting object. 3776 */ 3777 vm_map_copy_entry(old_map, new_map, old_entry, new_entry); 3778 break; 3779 } 3780 } 3781 3782 /* 3783 * When forking user-kernel shared maps, the map might change in the 3784 * child so do not try to copy the underlying pmap entries. 3785 */ 3786 static 3787 void 3788 vmspace_fork_uksmap_entry(vm_map_t old_map, vm_map_t new_map, 3789 vm_map_entry_t old_entry, int *countp) 3790 { 3791 vm_map_entry_t new_entry; 3792 3793 new_entry = vm_map_entry_create(countp); 3794 *new_entry = *old_entry; 3795 3796 new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; 3797 new_entry->wired_count = 0; 3798 KKASSERT(new_entry->ba.backing_ba == NULL); 3799 vm_map_backing_replicated(new_map, new_entry, 0); 3800 3801 vm_map_entry_link(new_map, new_entry); 3802 } 3803 3804 /* 3805 * Create an auto-grow stack entry 3806 * 3807 * No requirements. 3808 */ 3809 int 3810 vm_map_stack (vm_map_t map, vm_offset_t *addrbos, vm_size_t max_ssize, 3811 int flags, vm_prot_t prot, vm_prot_t max, int cow) 3812 { 3813 vm_map_entry_t prev_entry; 3814 vm_map_entry_t next; 3815 vm_size_t init_ssize; 3816 int rv; 3817 int count; 3818 vm_offset_t tmpaddr; 3819 3820 cow |= MAP_IS_STACK; 3821 3822 if (max_ssize < sgrowsiz) 3823 init_ssize = max_ssize; 3824 else 3825 init_ssize = sgrowsiz; 3826 3827 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3828 vm_map_lock(map); 3829 3830 /* 3831 * Find space for the mapping 3832 */ 3833 if ((flags & (MAP_FIXED | MAP_TRYFIXED)) == 0) { 3834 if (vm_map_findspace(map, *addrbos, max_ssize, 1, 3835 flags, &tmpaddr)) { 3836 vm_map_unlock(map); 3837 vm_map_entry_release(count); 3838 return (KERN_NO_SPACE); 3839 } 3840 *addrbos = tmpaddr; 3841 } 3842 3843 /* If addr is already mapped, no go */ 3844 if (vm_map_lookup_entry(map, *addrbos, &prev_entry)) { 3845 vm_map_unlock(map); 3846 vm_map_entry_release(count); 3847 return (KERN_NO_SPACE); 3848 } 3849 3850 #if 0 3851 /* XXX already handled by kern_mmap() */ 3852 /* If we would blow our VMEM resource limit, no go */ 3853 if (map->size + init_ssize > 3854 curproc->p_rlimit[RLIMIT_VMEM].rlim_cur) { 3855 vm_map_unlock(map); 3856 vm_map_entry_release(count); 3857 return (KERN_NO_SPACE); 3858 } 3859 #endif 3860 3861 /* 3862 * If we can't accomodate max_ssize in the current mapping, 3863 * no go. However, we need to be aware that subsequent user 3864 * mappings might map into the space we have reserved for 3865 * stack, and currently this space is not protected. 3866 * 3867 * Hopefully we will at least detect this condition 3868 * when we try to grow the stack. 3869 */ 3870 if (prev_entry) 3871 next = vm_map_rb_tree_RB_NEXT(prev_entry); 3872 else 3873 next = RB_MIN(vm_map_rb_tree, &map->rb_root); 3874 3875 if (next && next->ba.start < *addrbos + max_ssize) { 3876 vm_map_unlock(map); 3877 vm_map_entry_release(count); 3878 return (KERN_NO_SPACE); 3879 } 3880 3881 /* 3882 * We initially map a stack of only init_ssize. We will 3883 * grow as needed later. Since this is to be a grow 3884 * down stack, we map at the top of the range. 3885 * 3886 * Note: we would normally expect prot and max to be 3887 * VM_PROT_ALL, and cow to be 0. Possibly we should 3888 * eliminate these as input parameters, and just 3889 * pass these values here in the insert call. 3890 */ 3891 rv = vm_map_insert(map, &count, NULL, NULL, 3892 0, *addrbos + max_ssize - init_ssize, 3893 *addrbos + max_ssize, 3894 VM_MAPTYPE_NORMAL, 3895 VM_SUBSYS_STACK, prot, max, cow); 3896 3897 /* Now set the avail_ssize amount */ 3898 if (rv == KERN_SUCCESS) { 3899 if (prev_entry) 3900 next = vm_map_rb_tree_RB_NEXT(prev_entry); 3901 else 3902 next = RB_MIN(vm_map_rb_tree, &map->rb_root); 3903 if (prev_entry != NULL) { 3904 vm_map_clip_end(map, 3905 prev_entry, 3906 *addrbos + max_ssize - init_ssize, 3907 &count); 3908 } 3909 if (next->ba.end != *addrbos + max_ssize || 3910 next->ba.start != *addrbos + max_ssize - init_ssize){ 3911 panic ("Bad entry start/end for new stack entry"); 3912 } else { 3913 next->aux.avail_ssize = max_ssize - init_ssize; 3914 } 3915 } 3916 3917 vm_map_unlock(map); 3918 vm_map_entry_release(count); 3919 return (rv); 3920 } 3921 3922 /* 3923 * Attempts to grow a vm stack entry. Returns KERN_SUCCESS if the 3924 * desired address is already mapped, or if we successfully grow 3925 * the stack. Also returns KERN_SUCCESS if addr is outside the 3926 * stack range (this is strange, but preserves compatibility with 3927 * the grow function in vm_machdep.c). 3928 * 3929 * No requirements. 3930 */ 3931 int 3932 vm_map_growstack (vm_map_t map, vm_offset_t addr) 3933 { 3934 vm_map_entry_t prev_entry; 3935 vm_map_entry_t stack_entry; 3936 vm_map_entry_t next; 3937 struct vmspace *vm; 3938 struct lwp *lp; 3939 struct proc *p; 3940 vm_offset_t end; 3941 int grow_amount; 3942 int rv = KERN_SUCCESS; 3943 int is_procstack; 3944 int use_read_lock = 1; 3945 int count; 3946 3947 /* 3948 * Find the vm 3949 */ 3950 lp = curthread->td_lwp; 3951 p = curthread->td_proc; 3952 KKASSERT(lp != NULL); 3953 vm = lp->lwp_vmspace; 3954 3955 /* 3956 * Growstack is only allowed on the current process. We disallow 3957 * other use cases, e.g. trying to access memory via procfs that 3958 * the stack hasn't grown into. 3959 */ 3960 if (map != &vm->vm_map) { 3961 return KERN_FAILURE; 3962 } 3963 3964 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 3965 Retry: 3966 if (use_read_lock) 3967 vm_map_lock_read(map); 3968 else 3969 vm_map_lock(map); 3970 3971 /* 3972 * If addr is already in the entry range, no need to grow. 3973 * prev_entry returns NULL if addr is at the head. 3974 */ 3975 if (vm_map_lookup_entry(map, addr, &prev_entry)) 3976 goto done; 3977 if (prev_entry) 3978 stack_entry = vm_map_rb_tree_RB_NEXT(prev_entry); 3979 else 3980 stack_entry = RB_MIN(vm_map_rb_tree, &map->rb_root); 3981 3982 if (stack_entry == NULL) 3983 goto done; 3984 if (prev_entry == NULL) 3985 end = stack_entry->ba.start - stack_entry->aux.avail_ssize; 3986 else 3987 end = prev_entry->ba.end; 3988 3989 /* 3990 * This next test mimics the old grow function in vm_machdep.c. 3991 * It really doesn't quite make sense, but we do it anyway 3992 * for compatibility. 3993 * 3994 * If not growable stack, return success. This signals the 3995 * caller to proceed as he would normally with normal vm. 3996 */ 3997 if (stack_entry->aux.avail_ssize < 1 || 3998 addr >= stack_entry->ba.start || 3999 addr < stack_entry->ba.start - stack_entry->aux.avail_ssize) { 4000 goto done; 4001 } 4002 4003 /* Find the minimum grow amount */ 4004 grow_amount = roundup (stack_entry->ba.start - addr, PAGE_SIZE); 4005 if (grow_amount > stack_entry->aux.avail_ssize) { 4006 rv = KERN_NO_SPACE; 4007 goto done; 4008 } 4009 4010 /* 4011 * If there is no longer enough space between the entries 4012 * nogo, and adjust the available space. Note: this 4013 * should only happen if the user has mapped into the 4014 * stack area after the stack was created, and is 4015 * probably an error. 4016 * 4017 * This also effectively destroys any guard page the user 4018 * might have intended by limiting the stack size. 4019 */ 4020 if (grow_amount > stack_entry->ba.start - end) { 4021 if (use_read_lock && vm_map_lock_upgrade(map)) { 4022 /* lost lock */ 4023 use_read_lock = 0; 4024 goto Retry; 4025 } 4026 use_read_lock = 0; 4027 stack_entry->aux.avail_ssize = stack_entry->ba.start - end; 4028 rv = KERN_NO_SPACE; 4029 goto done; 4030 } 4031 4032 is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr; 4033 4034 /* If this is the main process stack, see if we're over the 4035 * stack limit. 4036 */ 4037 if (is_procstack && (vm->vm_ssize + grow_amount > 4038 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 4039 rv = KERN_NO_SPACE; 4040 goto done; 4041 } 4042 4043 /* Round up the grow amount modulo SGROWSIZ */ 4044 grow_amount = roundup (grow_amount, sgrowsiz); 4045 if (grow_amount > stack_entry->aux.avail_ssize) { 4046 grow_amount = stack_entry->aux.avail_ssize; 4047 } 4048 if (is_procstack && (vm->vm_ssize + grow_amount > 4049 p->p_rlimit[RLIMIT_STACK].rlim_cur)) { 4050 grow_amount = p->p_rlimit[RLIMIT_STACK].rlim_cur - vm->vm_ssize; 4051 } 4052 4053 /* If we would blow our VMEM resource limit, no go */ 4054 if (map->size + grow_amount > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { 4055 rv = KERN_NO_SPACE; 4056 goto done; 4057 } 4058 4059 if (use_read_lock && vm_map_lock_upgrade(map)) { 4060 /* lost lock */ 4061 use_read_lock = 0; 4062 goto Retry; 4063 } 4064 use_read_lock = 0; 4065 4066 /* Get the preliminary new entry start value */ 4067 addr = stack_entry->ba.start - grow_amount; 4068 4069 /* If this puts us into the previous entry, cut back our growth 4070 * to the available space. Also, see the note above. 4071 */ 4072 if (addr < end) { 4073 stack_entry->aux.avail_ssize = stack_entry->ba.start - end; 4074 addr = end; 4075 } 4076 4077 rv = vm_map_insert(map, &count, NULL, NULL, 4078 0, addr, stack_entry->ba.start, 4079 VM_MAPTYPE_NORMAL, 4080 VM_SUBSYS_STACK, VM_PROT_ALL, VM_PROT_ALL, 0); 4081 4082 /* Adjust the available stack space by the amount we grew. */ 4083 if (rv == KERN_SUCCESS) { 4084 if (prev_entry) { 4085 vm_map_clip_end(map, prev_entry, addr, &count); 4086 next = vm_map_rb_tree_RB_NEXT(prev_entry); 4087 } else { 4088 next = RB_MIN(vm_map_rb_tree, &map->rb_root); 4089 } 4090 if (next->ba.end != stack_entry->ba.start || 4091 next->ba.start != addr) { 4092 panic ("Bad stack grow start/end in new stack entry"); 4093 } else { 4094 next->aux.avail_ssize = 4095 stack_entry->aux.avail_ssize - 4096 (next->ba.end - next->ba.start); 4097 if (is_procstack) { 4098 vm->vm_ssize += next->ba.end - 4099 next->ba.start; 4100 } 4101 } 4102 4103 if (map->flags & MAP_WIREFUTURE) 4104 vm_map_unwire(map, next->ba.start, next->ba.end, FALSE); 4105 } 4106 4107 done: 4108 if (use_read_lock) 4109 vm_map_unlock_read(map); 4110 else 4111 vm_map_unlock(map); 4112 vm_map_entry_release(count); 4113 return (rv); 4114 } 4115 4116 /* 4117 * Unshare the specified VM space for exec. If other processes are 4118 * mapped to it, then create a new one. The new vmspace is null. 4119 * 4120 * No requirements. 4121 */ 4122 void 4123 vmspace_exec(struct proc *p, struct vmspace *vmcopy) 4124 { 4125 struct vmspace *oldvmspace = p->p_vmspace; 4126 struct vmspace *newvmspace; 4127 vm_map_t map = &p->p_vmspace->vm_map; 4128 4129 /* 4130 * If we are execing a resident vmspace we fork it, otherwise 4131 * we create a new vmspace. Note that exitingcnt is not 4132 * copied to the new vmspace. 4133 */ 4134 lwkt_gettoken(&oldvmspace->vm_map.token); 4135 if (vmcopy) { 4136 newvmspace = vmspace_fork(vmcopy); 4137 lwkt_gettoken(&newvmspace->vm_map.token); 4138 } else { 4139 newvmspace = vmspace_alloc(vm_map_min(map), vm_map_max(map)); 4140 lwkt_gettoken(&newvmspace->vm_map.token); 4141 bcopy(&oldvmspace->vm_startcopy, &newvmspace->vm_startcopy, 4142 (caddr_t)&oldvmspace->vm_endcopy - 4143 (caddr_t)&oldvmspace->vm_startcopy); 4144 } 4145 4146 /* 4147 * Finish initializing the vmspace before assigning it 4148 * to the process. The vmspace will become the current vmspace 4149 * if p == curproc. 4150 */ 4151 pmap_pinit2(vmspace_pmap(newvmspace)); 4152 pmap_replacevm(p, newvmspace, 0); 4153 lwkt_reltoken(&newvmspace->vm_map.token); 4154 lwkt_reltoken(&oldvmspace->vm_map.token); 4155 vmspace_rel(oldvmspace); 4156 } 4157 4158 /* 4159 * Unshare the specified VM space for forcing COW. This 4160 * is called by rfork, for the (RFMEM|RFPROC) == 0 case. 4161 */ 4162 void 4163 vmspace_unshare(struct proc *p) 4164 { 4165 struct vmspace *oldvmspace = p->p_vmspace; 4166 struct vmspace *newvmspace; 4167 4168 lwkt_gettoken(&oldvmspace->vm_map.token); 4169 if (vmspace_getrefs(oldvmspace) == 1) { 4170 lwkt_reltoken(&oldvmspace->vm_map.token); 4171 return; 4172 } 4173 newvmspace = vmspace_fork(oldvmspace); 4174 lwkt_gettoken(&newvmspace->vm_map.token); 4175 pmap_pinit2(vmspace_pmap(newvmspace)); 4176 pmap_replacevm(p, newvmspace, 0); 4177 lwkt_reltoken(&newvmspace->vm_map.token); 4178 lwkt_reltoken(&oldvmspace->vm_map.token); 4179 vmspace_rel(oldvmspace); 4180 } 4181 4182 /* 4183 * vm_map_hint: return the beginning of the best area suitable for 4184 * creating a new mapping with "prot" protection. 4185 * 4186 * No requirements. 4187 */ 4188 vm_offset_t 4189 vm_map_hint(struct proc *p, vm_offset_t addr, vm_prot_t prot) 4190 { 4191 struct vmspace *vms = p->p_vmspace; 4192 struct rlimit limit; 4193 rlim_t dsiz; 4194 4195 /* 4196 * Acquire datasize limit for mmap() operation, 4197 * calculate nearest power of 2. 4198 */ 4199 if (kern_getrlimit(RLIMIT_DATA, &limit)) 4200 limit.rlim_cur = maxdsiz; 4201 dsiz = limit.rlim_cur; 4202 4203 if (!randomize_mmap || addr != 0) { 4204 /* 4205 * Set a reasonable start point for the hint if it was 4206 * not specified or if it falls within the heap space. 4207 * Hinted mmap()s do not allocate out of the heap space. 4208 */ 4209 if (addr == 0 || 4210 (addr >= round_page((vm_offset_t)vms->vm_taddr) && 4211 addr < round_page((vm_offset_t)vms->vm_daddr + dsiz))) { 4212 addr = round_page((vm_offset_t)vms->vm_daddr + dsiz); 4213 } 4214 4215 return addr; 4216 } 4217 4218 /* 4219 * randomize_mmap && addr == 0. For now randomize the 4220 * address within a dsiz range beyond the data limit. 4221 */ 4222 addr = (vm_offset_t)vms->vm_daddr + dsiz; 4223 if (dsiz) 4224 addr += (karc4random64() & 0x7FFFFFFFFFFFFFFFLU) % dsiz; 4225 return (round_page(addr)); 4226 } 4227 4228 /* 4229 * Finds the VM object, offset, and protection for a given virtual address 4230 * in the specified map, assuming a page fault of the type specified. 4231 * 4232 * Leaves the map in question locked for read; return values are guaranteed 4233 * until a vm_map_lookup_done call is performed. Note that the map argument 4234 * is in/out; the returned map must be used in the call to vm_map_lookup_done. 4235 * 4236 * A handle (out_entry) is returned for use in vm_map_lookup_done, to make 4237 * that fast. 4238 * 4239 * If a lookup is requested with "write protection" specified, the map may 4240 * be changed to perform virtual copying operations, although the data 4241 * referenced will remain the same. 4242 * 4243 * No requirements. 4244 */ 4245 int 4246 vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ 4247 vm_offset_t vaddr, 4248 vm_prot_t fault_typea, 4249 vm_map_entry_t *out_entry, /* OUT */ 4250 struct vm_map_backing **bap, /* OUT */ 4251 vm_pindex_t *pindex, /* OUT */ 4252 vm_prot_t *out_prot, /* OUT */ 4253 int *wflags) /* OUT */ 4254 { 4255 vm_map_entry_t entry; 4256 vm_map_t map = *var_map; 4257 vm_prot_t prot; 4258 vm_prot_t fault_type = fault_typea; 4259 int use_read_lock = 1; 4260 int rv = KERN_SUCCESS; 4261 int count; 4262 thread_t td = curthread; 4263 4264 /* 4265 * vm_map_entry_reserve() implements an important mitigation 4266 * against mmap() span running the kernel out of vm_map_entry 4267 * structures, but it can also cause an infinite call recursion. 4268 * Use td_nest_count to prevent an infinite recursion (allows 4269 * the vm_map code to dig into the pcpu vm_map_entry reserve). 4270 */ 4271 count = 0; 4272 if (td->td_nest_count == 0) { 4273 ++td->td_nest_count; 4274 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 4275 --td->td_nest_count; 4276 } 4277 RetryLookup: 4278 if (use_read_lock) 4279 vm_map_lock_read(map); 4280 else 4281 vm_map_lock(map); 4282 4283 /* 4284 * Always do a full lookup. The hint doesn't get us much anymore 4285 * now that the map is RB'd. 4286 */ 4287 cpu_ccfence(); 4288 *out_entry = NULL; 4289 *bap = NULL; 4290 4291 { 4292 vm_map_entry_t tmp_entry; 4293 4294 if (!vm_map_lookup_entry(map, vaddr, &tmp_entry)) { 4295 rv = KERN_INVALID_ADDRESS; 4296 goto done; 4297 } 4298 entry = tmp_entry; 4299 *out_entry = entry; 4300 } 4301 4302 /* 4303 * Handle submaps. 4304 */ 4305 if (entry->maptype == VM_MAPTYPE_SUBMAP) { 4306 vm_map_t old_map = map; 4307 4308 *var_map = map = entry->ba.sub_map; 4309 if (use_read_lock) 4310 vm_map_unlock_read(old_map); 4311 else 4312 vm_map_unlock(old_map); 4313 use_read_lock = 1; 4314 goto RetryLookup; 4315 } 4316 4317 /* 4318 * Check whether this task is allowed to have this page. 4319 * Note the special case for MAP_ENTRY_COW pages with an override. 4320 * This is to implement a forced COW for debuggers. 4321 */ 4322 if (fault_type & VM_PROT_OVERRIDE_WRITE) 4323 prot = entry->max_protection; 4324 else 4325 prot = entry->protection; 4326 4327 fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 4328 if ((fault_type & prot) != fault_type) { 4329 rv = KERN_PROTECTION_FAILURE; 4330 goto done; 4331 } 4332 4333 if ((entry->eflags & MAP_ENTRY_USER_WIRED) && 4334 (entry->eflags & MAP_ENTRY_COW) && 4335 (fault_type & VM_PROT_WRITE) && 4336 (fault_typea & VM_PROT_OVERRIDE_WRITE) == 0) { 4337 rv = KERN_PROTECTION_FAILURE; 4338 goto done; 4339 } 4340 4341 /* 4342 * If this page is not pageable, we have to get it for all possible 4343 * accesses. 4344 */ 4345 *wflags = 0; 4346 if (entry->wired_count) { 4347 *wflags |= FW_WIRED; 4348 prot = fault_type = entry->protection; 4349 } 4350 4351 /* 4352 * Virtual page tables may need to update the accessed (A) bit 4353 * in a page table entry. Upgrade the fault to a write fault for 4354 * that case if the map will support it. If the map does not support 4355 * it the page table entry simply will not be updated. 4356 */ 4357 if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { 4358 if (prot & VM_PROT_WRITE) 4359 fault_type |= VM_PROT_WRITE; 4360 } 4361 4362 if (curthread->td_lwp && curthread->td_lwp->lwp_vmspace && 4363 pmap_emulate_ad_bits(&curthread->td_lwp->lwp_vmspace->vm_pmap)) { 4364 if ((prot & VM_PROT_WRITE) == 0) 4365 fault_type |= VM_PROT_WRITE; 4366 } 4367 4368 /* 4369 * Only NORMAL and VPAGETABLE maps are object-based. UKSMAPs are not. 4370 */ 4371 if (entry->maptype != VM_MAPTYPE_NORMAL && 4372 entry->maptype != VM_MAPTYPE_VPAGETABLE) { 4373 *bap = NULL; 4374 goto skip; 4375 } 4376 4377 /* 4378 * If the entry was copy-on-write, we either ... 4379 */ 4380 if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { 4381 /* 4382 * If we want to write the page, we may as well handle that 4383 * now since we've got the map locked. 4384 * 4385 * If we don't need to write the page, we just demote the 4386 * permissions allowed. 4387 */ 4388 if (fault_type & VM_PROT_WRITE) { 4389 /* 4390 * Not allowed if TDF_NOFAULT is set as the shadowing 4391 * operation can deadlock against the faulting 4392 * function due to the copy-on-write. 4393 */ 4394 if (curthread->td_flags & TDF_NOFAULT) { 4395 rv = KERN_FAILURE_NOFAULT; 4396 goto done; 4397 } 4398 4399 /* 4400 * Make a new vm_map_backing + object, and place it 4401 * in the object chain. Note that no new references 4402 * have appeared -- one just moved from the map to 4403 * the new object. 4404 */ 4405 if (use_read_lock && vm_map_lock_upgrade(map)) { 4406 /* lost lock */ 4407 use_read_lock = 0; 4408 goto RetryLookup; 4409 } 4410 use_read_lock = 0; 4411 vm_map_entry_shadow(entry); 4412 *wflags |= FW_DIDCOW; 4413 } else { 4414 /* 4415 * We're attempting to read a copy-on-write page -- 4416 * don't allow writes. 4417 */ 4418 prot &= ~VM_PROT_WRITE; 4419 } 4420 } 4421 4422 /* 4423 * Create an object if necessary. This code also handles 4424 * partitioning large entries to improve vm_fault performance. 4425 */ 4426 if (entry->ba.object == NULL && !map->system_map) { 4427 if (use_read_lock && vm_map_lock_upgrade(map)) { 4428 /* lost lock */ 4429 use_read_lock = 0; 4430 goto RetryLookup; 4431 } 4432 use_read_lock = 0; 4433 4434 /* 4435 * Partition large entries, giving each its own VM object, 4436 * to improve concurrent fault performance. This is only 4437 * applicable to userspace. 4438 */ 4439 if (map != &kernel_map && 4440 entry->maptype == VM_MAPTYPE_NORMAL && 4441 ((entry->ba.start ^ entry->ba.end) & 4442 ~MAP_ENTRY_PARTITION_MASK) && 4443 vm_map_partition_enable) { 4444 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { 4445 entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; 4446 ++mycpu->gd_cnt.v_intrans_coll; 4447 ++mycpu->gd_cnt.v_intrans_wait; 4448 vm_map_transition_wait(map, 0); 4449 goto RetryLookup; 4450 } 4451 vm_map_entry_partition(map, entry, vaddr, &count); 4452 } 4453 vm_map_entry_allocate_object(entry); 4454 } 4455 4456 /* 4457 * Return the object/offset from this entry. If the entry was 4458 * copy-on-write or empty, it has been fixed up. 4459 */ 4460 *bap = &entry->ba; 4461 4462 skip: 4463 *pindex = OFF_TO_IDX((vaddr - entry->ba.start) + entry->ba.offset); 4464 4465 /* 4466 * Return whether this is the only map sharing this data. On 4467 * success we return with a read lock held on the map. On failure 4468 * we return with the map unlocked. 4469 */ 4470 *out_prot = prot; 4471 done: 4472 if (rv == KERN_SUCCESS) { 4473 if (use_read_lock == 0) 4474 vm_map_lock_downgrade(map); 4475 } else if (use_read_lock) { 4476 vm_map_unlock_read(map); 4477 } else { 4478 vm_map_unlock(map); 4479 } 4480 if (count > 0) 4481 vm_map_entry_release(count); 4482 4483 return (rv); 4484 } 4485 4486 /* 4487 * Releases locks acquired by a vm_map_lookup() 4488 * (according to the handle returned by that lookup). 4489 * 4490 * No other requirements. 4491 */ 4492 void 4493 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry, int count) 4494 { 4495 /* 4496 * Unlock the main-level map 4497 */ 4498 vm_map_unlock_read(map); 4499 if (count) 4500 vm_map_entry_release(count); 4501 } 4502 4503 static void 4504 vm_map_entry_partition(vm_map_t map, vm_map_entry_t entry, 4505 vm_offset_t vaddr, int *countp) 4506 { 4507 vaddr &= ~MAP_ENTRY_PARTITION_MASK; 4508 vm_map_clip_start(map, entry, vaddr, countp); 4509 vaddr += MAP_ENTRY_PARTITION_SIZE; 4510 vm_map_clip_end(map, entry, vaddr, countp); 4511 } 4512 4513 /* 4514 * Quick hack, needs some help to make it more SMP friendly. 4515 */ 4516 void 4517 vm_map_interlock(vm_map_t map, struct vm_map_ilock *ilock, 4518 vm_offset_t ran_beg, vm_offset_t ran_end) 4519 { 4520 struct vm_map_ilock *scan; 4521 4522 ilock->ran_beg = ran_beg; 4523 ilock->ran_end = ran_end; 4524 ilock->flags = 0; 4525 4526 spin_lock(&map->ilock_spin); 4527 restart: 4528 for (scan = map->ilock_base; scan; scan = scan->next) { 4529 if (ran_end > scan->ran_beg && ran_beg < scan->ran_end) { 4530 scan->flags |= ILOCK_WAITING; 4531 ssleep(scan, &map->ilock_spin, 0, "ilock", 0); 4532 goto restart; 4533 } 4534 } 4535 ilock->next = map->ilock_base; 4536 map->ilock_base = ilock; 4537 spin_unlock(&map->ilock_spin); 4538 } 4539 4540 void 4541 vm_map_deinterlock(vm_map_t map, struct vm_map_ilock *ilock) 4542 { 4543 struct vm_map_ilock *scan; 4544 struct vm_map_ilock **scanp; 4545 4546 spin_lock(&map->ilock_spin); 4547 scanp = &map->ilock_base; 4548 while ((scan = *scanp) != NULL) { 4549 if (scan == ilock) { 4550 *scanp = ilock->next; 4551 spin_unlock(&map->ilock_spin); 4552 if (ilock->flags & ILOCK_WAITING) 4553 wakeup(ilock); 4554 return; 4555 } 4556 scanp = &scan->next; 4557 } 4558 spin_unlock(&map->ilock_spin); 4559 panic("vm_map_deinterlock: missing ilock!"); 4560 } 4561 4562 #include "opt_ddb.h" 4563 #ifdef DDB 4564 #include <ddb/ddb.h> 4565 4566 /* 4567 * Debugging only 4568 */ 4569 DB_SHOW_COMMAND(map, vm_map_print) 4570 { 4571 static int nlines; 4572 /* XXX convert args. */ 4573 vm_map_t map = (vm_map_t)addr; 4574 boolean_t full = have_addr; 4575 4576 vm_map_entry_t entry; 4577 4578 db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", 4579 (void *)map, 4580 (void *)map->pmap, map->nentries, map->timestamp); 4581 nlines++; 4582 4583 if (!full && db_indent) 4584 return; 4585 4586 db_indent += 2; 4587 RB_FOREACH(entry, vm_map_rb_tree, &map->rb_root) { 4588 db_iprintf("map entry %p: start=%p, end=%p\n", 4589 (void *)entry, 4590 (void *)entry->ba.start, (void *)entry->ba.end); 4591 nlines++; 4592 { 4593 static char *inheritance_name[4] = 4594 {"share", "copy", "none", "donate_copy"}; 4595 4596 db_iprintf(" prot=%x/%x/%s", 4597 entry->protection, 4598 entry->max_protection, 4599 inheritance_name[(int)(unsigned char) 4600 entry->inheritance]); 4601 if (entry->wired_count != 0) 4602 db_printf(", wired"); 4603 } 4604 switch(entry->maptype) { 4605 case VM_MAPTYPE_SUBMAP: 4606 /* XXX no %qd in kernel. Truncate entry->ba.offset. */ 4607 db_printf(", share=%p, offset=0x%lx\n", 4608 (void *)entry->ba.sub_map, 4609 (long)entry->ba.offset); 4610 nlines++; 4611 4612 db_indent += 2; 4613 vm_map_print((db_expr_t)(intptr_t)entry->ba.sub_map, 4614 full, 0, NULL); 4615 db_indent -= 2; 4616 break; 4617 case VM_MAPTYPE_NORMAL: 4618 case VM_MAPTYPE_VPAGETABLE: 4619 /* XXX no %qd in kernel. Truncate entry->ba.offset. */ 4620 db_printf(", object=%p, offset=0x%lx", 4621 (void *)entry->ba.object, 4622 (long)entry->ba.offset); 4623 if (entry->eflags & MAP_ENTRY_COW) 4624 db_printf(", copy (%s)", 4625 (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); 4626 db_printf("\n"); 4627 nlines++; 4628 4629 if (entry->ba.object) { 4630 db_indent += 2; 4631 vm_object_print((db_expr_t)(intptr_t) 4632 entry->ba.object, 4633 full, 0, NULL); 4634 nlines += 4; 4635 db_indent -= 2; 4636 } 4637 break; 4638 case VM_MAPTYPE_UKSMAP: 4639 db_printf(", uksmap=%p, offset=0x%lx", 4640 (void *)entry->ba.uksmap, 4641 (long)entry->ba.offset); 4642 if (entry->eflags & MAP_ENTRY_COW) 4643 db_printf(", copy (%s)", 4644 (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); 4645 db_printf("\n"); 4646 nlines++; 4647 break; 4648 default: 4649 break; 4650 } 4651 } 4652 db_indent -= 2; 4653 if (db_indent == 0) 4654 nlines = 0; 4655 } 4656 4657 /* 4658 * Debugging only 4659 */ 4660 DB_SHOW_COMMAND(procvm, procvm) 4661 { 4662 struct proc *p; 4663 4664 if (have_addr) { 4665 p = (struct proc *) addr; 4666 } else { 4667 p = curproc; 4668 } 4669 4670 db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", 4671 (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, 4672 (void *)vmspace_pmap(p->p_vmspace)); 4673 4674 vm_map_print((db_expr_t)(intptr_t)&p->p_vmspace->vm_map, 1, 0, NULL); 4675 } 4676 4677 #endif /* DDB */ 4678