1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 */ 62 63 /* 64 * Kernel memory management. 65 */ 66 67 #include <sys/cdefs.h> 68 __FBSDID("$FreeBSD$"); 69 70 #include "opt_vm.h" 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/kernel.h> /* for ticks and hz */ 75 #include <sys/domainset.h> 76 #include <sys/eventhandler.h> 77 #include <sys/lock.h> 78 #include <sys/proc.h> 79 #include <sys/malloc.h> 80 #include <sys/rwlock.h> 81 #include <sys/sysctl.h> 82 #include <sys/vmem.h> 83 #include <sys/vmmeter.h> 84 85 #include <vm/vm.h> 86 #include <vm/vm_param.h> 87 #include <vm/vm_domainset.h> 88 #include <vm/vm_kern.h> 89 #include <vm/pmap.h> 90 #include <vm/vm_map.h> 91 #include <vm/vm_object.h> 92 #include <vm/vm_page.h> 93 #include <vm/vm_pageout.h> 94 #include <vm/vm_phys.h> 95 #include <vm/vm_pagequeue.h> 96 #include <vm/vm_radix.h> 97 #include <vm/vm_extern.h> 98 #include <vm/uma.h> 99 100 vm_map_t kernel_map; 101 vm_map_t exec_map; 102 vm_map_t pipe_map; 103 104 const void *zero_region; 105 CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0); 106 107 /* NB: Used by kernel debuggers. */ 108 const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS; 109 110 u_int exec_map_entry_size; 111 u_int exec_map_entries; 112 113 SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD, 114 SYSCTL_NULL_ULONG_PTR, VM_MIN_KERNEL_ADDRESS, "Min kernel address"); 115 116 SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD, 117 #if defined(__arm__) || defined(__sparc64__) 118 &vm_max_kernel_address, 0, 119 #else 120 SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS, 121 #endif 122 "Max kernel address"); 123 124 #if VM_NRESERVLEVEL > 0 125 #define KVA_QUANTUM_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT) 126 #else 127 /* On non-superpage architectures we want large import sizes. */ 128 #define KVA_QUANTUM_SHIFT (8 + PAGE_SHIFT) 129 #endif 130 #define KVA_QUANTUM (1 << KVA_QUANTUM_SHIFT) 131 132 /* 133 * kva_alloc: 134 * 135 * Allocate a virtual address range with no underlying object and 136 * no initial mapping to physical memory. Any mapping from this 137 * range to physical memory must be explicitly created prior to 138 * its use, typically with pmap_qenter(). Any attempt to create 139 * a mapping on demand through vm_fault() will result in a panic. 140 */ 141 vm_offset_t 142 kva_alloc(vm_size_t size) 143 { 144 vm_offset_t addr; 145 146 size = round_page(size); 147 if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr)) 148 return (0); 149 150 return (addr); 151 } 152 153 /* 154 * kva_free: 155 * 156 * Release a region of kernel virtual memory allocated 157 * with kva_alloc, and return the physical pages 158 * associated with that region. 159 * 160 * This routine may not block on kernel maps. 161 */ 162 void 163 kva_free(vm_offset_t addr, vm_size_t size) 164 { 165 166 size = round_page(size); 167 vmem_free(kernel_arena, addr, size); 168 } 169 170 /* 171 * Allocates a region from the kernel address map and physical pages 172 * within the specified address range to the kernel object. Creates a 173 * wired mapping from this region to these pages, and returns the 174 * region's starting virtual address. The allocated pages are not 175 * necessarily physically contiguous. If M_ZERO is specified through the 176 * given flags, then the pages are zeroed before they are mapped. 177 */ 178 static vm_offset_t 179 kmem_alloc_attr_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 180 vm_paddr_t high, vm_memattr_t memattr) 181 { 182 vmem_t *vmem; 183 vm_object_t object = kernel_object; 184 vm_offset_t addr, i, offset; 185 vm_page_t m; 186 int pflags, tries; 187 vm_prot_t prot; 188 189 size = round_page(size); 190 vmem = vm_dom[domain].vmd_kernel_arena; 191 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr)) 192 return (0); 193 offset = addr - VM_MIN_KERNEL_ADDRESS; 194 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 195 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 196 pflags |= VM_ALLOC_NOWAIT; 197 prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW; 198 VM_OBJECT_WLOCK(object); 199 for (i = 0; i < size; i += PAGE_SIZE) { 200 tries = 0; 201 retry: 202 m = vm_page_alloc_contig_domain(object, atop(offset + i), 203 domain, pflags, 1, low, high, PAGE_SIZE, 0, memattr); 204 if (m == NULL) { 205 VM_OBJECT_WUNLOCK(object); 206 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 207 if (!vm_page_reclaim_contig_domain(domain, 208 pflags, 1, low, high, PAGE_SIZE, 0) && 209 (flags & M_WAITOK) != 0) 210 vm_wait_domain(domain); 211 VM_OBJECT_WLOCK(object); 212 tries++; 213 goto retry; 214 } 215 kmem_unback(object, addr, i); 216 vmem_free(vmem, addr, size); 217 return (0); 218 } 219 KASSERT(vm_phys_domain(m) == domain, 220 ("kmem_alloc_attr_domain: Domain mismatch %d != %d", 221 vm_phys_domain(m), domain)); 222 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 223 pmap_zero_page(m); 224 m->valid = VM_PAGE_BITS_ALL; 225 pmap_enter(kernel_pmap, addr + i, m, prot, 226 prot | PMAP_ENTER_WIRED, 0); 227 } 228 VM_OBJECT_WUNLOCK(object); 229 return (addr); 230 } 231 232 vm_offset_t 233 kmem_alloc_attr(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 234 vm_memattr_t memattr) 235 { 236 237 return (kmem_alloc_attr_domainset(DOMAINSET_RR(), size, flags, low, 238 high, memattr)); 239 } 240 241 vm_offset_t 242 kmem_alloc_attr_domainset(struct domainset *ds, vm_size_t size, int flags, 243 vm_paddr_t low, vm_paddr_t high, vm_memattr_t memattr) 244 { 245 struct vm_domainset_iter di; 246 vm_offset_t addr; 247 int domain; 248 249 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 250 do { 251 addr = kmem_alloc_attr_domain(domain, size, flags, low, high, 252 memattr); 253 if (addr != 0) 254 break; 255 } while (vm_domainset_iter_policy(&di, &domain) == 0); 256 257 return (addr); 258 } 259 260 /* 261 * Allocates a region from the kernel address map and physically 262 * contiguous pages within the specified address range to the kernel 263 * object. Creates a wired mapping from this region to these pages, and 264 * returns the region's starting virtual address. If M_ZERO is specified 265 * through the given flags, then the pages are zeroed before they are 266 * mapped. 267 */ 268 static vm_offset_t 269 kmem_alloc_contig_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 270 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 271 vm_memattr_t memattr) 272 { 273 vmem_t *vmem; 274 vm_object_t object = kernel_object; 275 vm_offset_t addr, offset, tmp; 276 vm_page_t end_m, m; 277 u_long npages; 278 int pflags, tries; 279 280 size = round_page(size); 281 vmem = vm_dom[domain].vmd_kernel_arena; 282 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 283 return (0); 284 offset = addr - VM_MIN_KERNEL_ADDRESS; 285 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 286 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 287 pflags |= VM_ALLOC_NOWAIT; 288 npages = atop(size); 289 VM_OBJECT_WLOCK(object); 290 tries = 0; 291 retry: 292 m = vm_page_alloc_contig_domain(object, atop(offset), domain, pflags, 293 npages, low, high, alignment, boundary, memattr); 294 if (m == NULL) { 295 VM_OBJECT_WUNLOCK(object); 296 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 297 if (!vm_page_reclaim_contig_domain(domain, pflags, 298 npages, low, high, alignment, boundary) && 299 (flags & M_WAITOK) != 0) 300 vm_wait_domain(domain); 301 VM_OBJECT_WLOCK(object); 302 tries++; 303 goto retry; 304 } 305 vmem_free(vmem, addr, size); 306 return (0); 307 } 308 KASSERT(vm_phys_domain(m) == domain, 309 ("kmem_alloc_contig_domain: Domain mismatch %d != %d", 310 vm_phys_domain(m), domain)); 311 end_m = m + npages; 312 tmp = addr; 313 for (; m < end_m; m++) { 314 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 315 pmap_zero_page(m); 316 m->valid = VM_PAGE_BITS_ALL; 317 pmap_enter(kernel_pmap, tmp, m, VM_PROT_RW, 318 VM_PROT_RW | PMAP_ENTER_WIRED, 0); 319 tmp += PAGE_SIZE; 320 } 321 VM_OBJECT_WUNLOCK(object); 322 return (addr); 323 } 324 325 vm_offset_t 326 kmem_alloc_contig(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 327 u_long alignment, vm_paddr_t boundary, vm_memattr_t memattr) 328 { 329 330 return (kmem_alloc_contig_domainset(DOMAINSET_RR(), size, flags, low, 331 high, alignment, boundary, memattr)); 332 } 333 334 vm_offset_t 335 kmem_alloc_contig_domainset(struct domainset *ds, vm_size_t size, int flags, 336 vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 337 vm_memattr_t memattr) 338 { 339 struct vm_domainset_iter di; 340 vm_offset_t addr; 341 int domain; 342 343 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 344 do { 345 addr = kmem_alloc_contig_domain(domain, size, flags, low, high, 346 alignment, boundary, memattr); 347 if (addr != 0) 348 break; 349 } while (vm_domainset_iter_policy(&di, &domain) == 0); 350 351 return (addr); 352 } 353 354 /* 355 * kmem_suballoc: 356 * 357 * Allocates a map to manage a subrange 358 * of the kernel virtual address space. 359 * 360 * Arguments are as follows: 361 * 362 * parent Map to take range from 363 * min, max Returned endpoints of map 364 * size Size of range to find 365 * superpage_align Request that min is superpage aligned 366 */ 367 vm_map_t 368 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 369 vm_size_t size, boolean_t superpage_align) 370 { 371 int ret; 372 vm_map_t result; 373 374 size = round_page(size); 375 376 *min = vm_map_min(parent); 377 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 378 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 379 MAP_ACC_NO_CHARGE); 380 if (ret != KERN_SUCCESS) 381 panic("kmem_suballoc: bad status return of %d", ret); 382 *max = *min + size; 383 result = vm_map_create(vm_map_pmap(parent), *min, *max); 384 if (result == NULL) 385 panic("kmem_suballoc: cannot create submap"); 386 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 387 panic("kmem_suballoc: unable to change range to submap"); 388 return (result); 389 } 390 391 /* 392 * kmem_malloc_domain: 393 * 394 * Allocate wired-down pages in the kernel's address space. 395 */ 396 static vm_offset_t 397 kmem_malloc_domain(int domain, vm_size_t size, int flags) 398 { 399 vmem_t *arena; 400 vm_offset_t addr; 401 int rv; 402 403 #if VM_NRESERVLEVEL > 0 404 if (__predict_true((flags & M_EXEC) == 0)) 405 arena = vm_dom[domain].vmd_kernel_arena; 406 else 407 arena = vm_dom[domain].vmd_kernel_rwx_arena; 408 #else 409 arena = vm_dom[domain].vmd_kernel_arena; 410 #endif 411 size = round_page(size); 412 if (vmem_alloc(arena, size, flags | M_BESTFIT, &addr)) 413 return (0); 414 415 rv = kmem_back_domain(domain, kernel_object, addr, size, flags); 416 if (rv != KERN_SUCCESS) { 417 vmem_free(arena, addr, size); 418 return (0); 419 } 420 return (addr); 421 } 422 423 vm_offset_t 424 kmem_malloc(vm_size_t size, int flags) 425 { 426 427 return (kmem_malloc_domainset(DOMAINSET_RR(), size, flags)); 428 } 429 430 vm_offset_t 431 kmem_malloc_domainset(struct domainset *ds, vm_size_t size, int flags) 432 { 433 struct vm_domainset_iter di; 434 vm_offset_t addr; 435 int domain; 436 437 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 438 do { 439 addr = kmem_malloc_domain(domain, size, flags); 440 if (addr != 0) 441 break; 442 } while (vm_domainset_iter_policy(&di, &domain) == 0); 443 444 return (addr); 445 } 446 447 /* 448 * kmem_back_domain: 449 * 450 * Allocate physical pages from the specified domain for the specified 451 * virtual address range. 452 */ 453 int 454 kmem_back_domain(int domain, vm_object_t object, vm_offset_t addr, 455 vm_size_t size, int flags) 456 { 457 vm_offset_t offset, i; 458 vm_page_t m, mpred; 459 vm_prot_t prot; 460 int pflags; 461 462 KASSERT(object == kernel_object, 463 ("kmem_back_domain: only supports kernel object.")); 464 465 offset = addr - VM_MIN_KERNEL_ADDRESS; 466 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 467 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 468 if (flags & M_WAITOK) 469 pflags |= VM_ALLOC_WAITFAIL; 470 prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW; 471 472 i = 0; 473 VM_OBJECT_WLOCK(object); 474 retry: 475 mpred = vm_radix_lookup_le(&object->rtree, atop(offset + i)); 476 for (; i < size; i += PAGE_SIZE, mpred = m) { 477 m = vm_page_alloc_domain_after(object, atop(offset + i), 478 domain, pflags, mpred); 479 480 /* 481 * Ran out of space, free everything up and return. Don't need 482 * to lock page queues here as we know that the pages we got 483 * aren't on any queues. 484 */ 485 if (m == NULL) { 486 if ((flags & M_NOWAIT) == 0) 487 goto retry; 488 VM_OBJECT_WUNLOCK(object); 489 kmem_unback(object, addr, i); 490 return (KERN_NO_SPACE); 491 } 492 KASSERT(vm_phys_domain(m) == domain, 493 ("kmem_back_domain: Domain mismatch %d != %d", 494 vm_phys_domain(m), domain)); 495 if (flags & M_ZERO && (m->flags & PG_ZERO) == 0) 496 pmap_zero_page(m); 497 KASSERT((m->oflags & VPO_UNMANAGED) != 0, 498 ("kmem_malloc: page %p is managed", m)); 499 m->valid = VM_PAGE_BITS_ALL; 500 pmap_enter(kernel_pmap, addr + i, m, prot, 501 prot | PMAP_ENTER_WIRED, 0); 502 #if VM_NRESERVLEVEL > 0 503 if (__predict_false((prot & VM_PROT_EXECUTE) != 0)) 504 m->oflags |= VPO_KMEM_EXEC; 505 #endif 506 } 507 VM_OBJECT_WUNLOCK(object); 508 509 return (KERN_SUCCESS); 510 } 511 512 /* 513 * kmem_back: 514 * 515 * Allocate physical pages for the specified virtual address range. 516 */ 517 int 518 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 519 { 520 vm_offset_t end, next, start; 521 int domain, rv; 522 523 KASSERT(object == kernel_object, 524 ("kmem_back: only supports kernel object.")); 525 526 for (start = addr, end = addr + size; addr < end; addr = next) { 527 /* 528 * We must ensure that pages backing a given large virtual page 529 * all come from the same physical domain. 530 */ 531 if (vm_ndomains > 1) { 532 domain = (addr >> KVA_QUANTUM_SHIFT) % vm_ndomains; 533 while (VM_DOMAIN_EMPTY(domain)) 534 domain++; 535 next = roundup2(addr + 1, KVA_QUANTUM); 536 if (next > end || next < start) 537 next = end; 538 } else { 539 domain = 0; 540 next = end; 541 } 542 rv = kmem_back_domain(domain, object, addr, next - addr, flags); 543 if (rv != KERN_SUCCESS) { 544 kmem_unback(object, start, addr - start); 545 break; 546 } 547 } 548 return (rv); 549 } 550 551 /* 552 * kmem_unback: 553 * 554 * Unmap and free the physical pages underlying the specified virtual 555 * address range. 556 * 557 * A physical page must exist within the specified object at each index 558 * that is being unmapped. 559 */ 560 static struct vmem * 561 _kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 562 { 563 struct vmem *arena; 564 vm_page_t m, next; 565 vm_offset_t end, offset; 566 int domain; 567 568 KASSERT(object == kernel_object, 569 ("kmem_unback: only supports kernel object.")); 570 571 if (size == 0) 572 return (NULL); 573 pmap_remove(kernel_pmap, addr, addr + size); 574 offset = addr - VM_MIN_KERNEL_ADDRESS; 575 end = offset + size; 576 VM_OBJECT_WLOCK(object); 577 m = vm_page_lookup(object, atop(offset)); 578 domain = vm_phys_domain(m); 579 #if VM_NRESERVLEVEL > 0 580 if (__predict_true((m->oflags & VPO_KMEM_EXEC) == 0)) 581 arena = vm_dom[domain].vmd_kernel_arena; 582 else 583 arena = vm_dom[domain].vmd_kernel_rwx_arena; 584 #else 585 arena = vm_dom[domain].vmd_kernel_arena; 586 #endif 587 for (; offset < end; offset += PAGE_SIZE, m = next) { 588 next = vm_page_next(m); 589 vm_page_unwire(m, PQ_NONE); 590 vm_page_free(m); 591 } 592 VM_OBJECT_WUNLOCK(object); 593 594 return (arena); 595 } 596 597 void 598 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 599 { 600 601 (void)_kmem_unback(object, addr, size); 602 } 603 604 /* 605 * kmem_free: 606 * 607 * Free memory allocated with kmem_malloc. The size must match the 608 * original allocation. 609 */ 610 void 611 kmem_free(vm_offset_t addr, vm_size_t size) 612 { 613 struct vmem *arena; 614 615 size = round_page(size); 616 arena = _kmem_unback(kernel_object, addr, size); 617 if (arena != NULL) 618 vmem_free(arena, addr, size); 619 } 620 621 /* 622 * kmap_alloc_wait: 623 * 624 * Allocates pageable memory from a sub-map of the kernel. If the submap 625 * has no room, the caller sleeps waiting for more memory in the submap. 626 * 627 * This routine may block. 628 */ 629 vm_offset_t 630 kmap_alloc_wait(vm_map_t map, vm_size_t size) 631 { 632 vm_offset_t addr; 633 634 size = round_page(size); 635 if (!swap_reserve(size)) 636 return (0); 637 638 for (;;) { 639 /* 640 * To make this work for more than one map, use the map's lock 641 * to lock out sleepers/wakers. 642 */ 643 vm_map_lock(map); 644 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0) 645 break; 646 /* no space now; see if we can ever get space */ 647 if (vm_map_max(map) - vm_map_min(map) < size) { 648 vm_map_unlock(map); 649 swap_release(size); 650 return (0); 651 } 652 map->needs_wakeup = TRUE; 653 vm_map_unlock_and_wait(map, 0); 654 } 655 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_RW, VM_PROT_RW, 656 MAP_ACC_CHARGED); 657 vm_map_unlock(map); 658 return (addr); 659 } 660 661 /* 662 * kmap_free_wakeup: 663 * 664 * Returns memory to a submap of the kernel, and wakes up any processes 665 * waiting for memory in that map. 666 */ 667 void 668 kmap_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 669 { 670 671 vm_map_lock(map); 672 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 673 if (map->needs_wakeup) { 674 map->needs_wakeup = FALSE; 675 vm_map_wakeup(map); 676 } 677 vm_map_unlock(map); 678 } 679 680 void 681 kmem_init_zero_region(void) 682 { 683 vm_offset_t addr, i; 684 vm_page_t m; 685 686 /* 687 * Map a single physical page of zeros to a larger virtual range. 688 * This requires less looping in places that want large amounts of 689 * zeros, while not using much more physical resources. 690 */ 691 addr = kva_alloc(ZERO_REGION_SIZE); 692 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 693 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 694 if ((m->flags & PG_ZERO) == 0) 695 pmap_zero_page(m); 696 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 697 pmap_qenter(addr + i, &m, 1); 698 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 699 700 zero_region = (const void *)addr; 701 } 702 703 /* 704 * Import KVA from the kernel map into the kernel arena. 705 */ 706 static int 707 kva_import(void *unused, vmem_size_t size, int flags, vmem_addr_t *addrp) 708 { 709 vm_offset_t addr; 710 int result; 711 712 KASSERT((size % KVA_QUANTUM) == 0, 713 ("kva_import: Size %jd is not a multiple of %d", 714 (intmax_t)size, (int)KVA_QUANTUM)); 715 addr = vm_map_min(kernel_map); 716 result = vm_map_find(kernel_map, NULL, 0, &addr, size, 0, 717 VMFS_SUPER_SPACE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 718 if (result != KERN_SUCCESS) 719 return (ENOMEM); 720 721 *addrp = addr; 722 723 return (0); 724 } 725 726 /* 727 * Import KVA from a parent arena into a per-domain arena. Imports must be 728 * KVA_QUANTUM-aligned and a multiple of KVA_QUANTUM in size. 729 */ 730 static int 731 kva_import_domain(void *arena, vmem_size_t size, int flags, vmem_addr_t *addrp) 732 { 733 734 KASSERT((size % KVA_QUANTUM) == 0, 735 ("kva_import_domain: Size %jd is not a multiple of %d", 736 (intmax_t)size, (int)KVA_QUANTUM)); 737 return (vmem_xalloc(arena, size, KVA_QUANTUM, 0, 0, VMEM_ADDR_MIN, 738 VMEM_ADDR_MAX, flags, addrp)); 739 } 740 741 /* 742 * kmem_init: 743 * 744 * Create the kernel map; insert a mapping covering kernel text, 745 * data, bss, and all space allocated thus far (`boostrap' data). The 746 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 747 * `start' as allocated, and the range between `start' and `end' as free. 748 * Create the kernel vmem arena and its per-domain children. 749 */ 750 void 751 kmem_init(vm_offset_t start, vm_offset_t end) 752 { 753 vm_map_t m; 754 int domain; 755 756 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 757 m->system_map = 1; 758 vm_map_lock(m); 759 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 760 kernel_map = m; 761 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 762 #ifdef __amd64__ 763 KERNBASE, 764 #else 765 VM_MIN_KERNEL_ADDRESS, 766 #endif 767 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 768 /* ... and ending with the completion of the above `insert' */ 769 vm_map_unlock(m); 770 771 /* 772 * Initialize the kernel_arena. This can grow on demand. 773 */ 774 vmem_init(kernel_arena, "kernel arena", 0, 0, PAGE_SIZE, 0, 0); 775 vmem_set_import(kernel_arena, kva_import, NULL, NULL, KVA_QUANTUM); 776 777 for (domain = 0; domain < vm_ndomains; domain++) { 778 /* 779 * Initialize the per-domain arenas. These are used to color 780 * the KVA space in a way that ensures that virtual large pages 781 * are backed by memory from the same physical domain, 782 * maximizing the potential for superpage promotion. 783 */ 784 vm_dom[domain].vmd_kernel_arena = vmem_create( 785 "kernel arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK); 786 vmem_set_import(vm_dom[domain].vmd_kernel_arena, 787 kva_import_domain, NULL, kernel_arena, KVA_QUANTUM); 788 789 /* 790 * In architectures with superpages, maintain separate arenas 791 * for allocations with permissions that differ from the 792 * "standard" read/write permissions used for kernel memory, 793 * so as not to inhibit superpage promotion. 794 */ 795 #if VM_NRESERVLEVEL > 0 796 vm_dom[domain].vmd_kernel_rwx_arena = vmem_create( 797 "kernel rwx arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK); 798 vmem_set_import(vm_dom[domain].vmd_kernel_rwx_arena, 799 kva_import_domain, (vmem_release_t *)vmem_xfree, 800 kernel_arena, KVA_QUANTUM); 801 #endif 802 } 803 } 804 805 /* 806 * kmem_bootstrap_free: 807 * 808 * Free pages backing preloaded data (e.g., kernel modules) to the 809 * system. Currently only supported on platforms that create a 810 * vm_phys segment for preloaded data. 811 */ 812 void 813 kmem_bootstrap_free(vm_offset_t start, vm_size_t size) 814 { 815 #if defined(__i386__) || defined(__amd64__) 816 struct vm_domain *vmd; 817 vm_offset_t end, va; 818 vm_paddr_t pa; 819 vm_page_t m; 820 821 end = trunc_page(start + size); 822 start = round_page(start); 823 824 for (va = start; va < end; va += PAGE_SIZE) { 825 pa = pmap_kextract(va); 826 m = PHYS_TO_VM_PAGE(pa); 827 828 vmd = vm_pagequeue_domain(m); 829 vm_domain_free_lock(vmd); 830 vm_phys_free_pages(m, 0); 831 vm_domain_free_unlock(vmd); 832 833 vm_domain_freecnt_inc(vmd, 1); 834 vm_cnt.v_page_count++; 835 } 836 pmap_remove(kernel_pmap, start, end); 837 (void)vmem_add(kernel_arena, start, end - start, M_WAITOK); 838 #endif 839 } 840 841 #ifdef DIAGNOSTIC 842 /* 843 * Allow userspace to directly trigger the VM drain routine for testing 844 * purposes. 845 */ 846 static int 847 debug_vm_lowmem(SYSCTL_HANDLER_ARGS) 848 { 849 int error, i; 850 851 i = 0; 852 error = sysctl_handle_int(oidp, &i, 0, req); 853 if (error) 854 return (error); 855 if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0) 856 return (EINVAL); 857 if (i != 0) 858 EVENTHANDLER_INVOKE(vm_lowmem, i); 859 return (0); 860 } 861 862 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0, 863 debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags"); 864 #endif 865