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 /* 125 * kva_alloc: 126 * 127 * Allocate a virtual address range with no underlying object and 128 * no initial mapping to physical memory. Any mapping from this 129 * range to physical memory must be explicitly created prior to 130 * its use, typically with pmap_qenter(). Any attempt to create 131 * a mapping on demand through vm_fault() will result in a panic. 132 */ 133 vm_offset_t 134 kva_alloc(vm_size_t size) 135 { 136 vm_offset_t addr; 137 138 size = round_page(size); 139 if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr)) 140 return (0); 141 142 return (addr); 143 } 144 145 /* 146 * kva_free: 147 * 148 * Release a region of kernel virtual memory allocated 149 * with kva_alloc, and return the physical pages 150 * associated with that region. 151 * 152 * This routine may not block on kernel maps. 153 */ 154 void 155 kva_free(vm_offset_t addr, vm_size_t size) 156 { 157 158 size = round_page(size); 159 vmem_free(kernel_arena, addr, size); 160 } 161 162 /* 163 * Allocates a region from the kernel address map and physical pages 164 * within the specified address range to the kernel object. Creates a 165 * wired mapping from this region to these pages, and returns the 166 * region's starting virtual address. The allocated pages are not 167 * necessarily physically contiguous. If M_ZERO is specified through the 168 * given flags, then the pages are zeroed before they are mapped. 169 */ 170 vm_offset_t 171 kmem_alloc_attr_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 172 vm_paddr_t high, vm_memattr_t memattr) 173 { 174 vmem_t *vmem; 175 vm_object_t object = kernel_object; 176 vm_offset_t addr, i, offset; 177 vm_page_t m; 178 int pflags, tries; 179 180 size = round_page(size); 181 vmem = vm_dom[domain].vmd_kernel_arena; 182 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr)) 183 return (0); 184 offset = addr - VM_MIN_KERNEL_ADDRESS; 185 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 186 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 187 pflags |= VM_ALLOC_NOWAIT; 188 VM_OBJECT_WLOCK(object); 189 for (i = 0; i < size; i += PAGE_SIZE) { 190 tries = 0; 191 retry: 192 m = vm_page_alloc_contig_domain(object, atop(offset + i), 193 domain, pflags, 1, low, high, PAGE_SIZE, 0, memattr); 194 if (m == NULL) { 195 VM_OBJECT_WUNLOCK(object); 196 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 197 if (!vm_page_reclaim_contig_domain(domain, 198 pflags, 1, low, high, PAGE_SIZE, 0) && 199 (flags & M_WAITOK) != 0) 200 vm_wait_domain(domain); 201 VM_OBJECT_WLOCK(object); 202 tries++; 203 goto retry; 204 } 205 kmem_unback(object, addr, i); 206 vmem_free(vmem, addr, size); 207 return (0); 208 } 209 KASSERT(vm_phys_domain(m) == domain, 210 ("kmem_alloc_attr_domain: Domain mismatch %d != %d", 211 vm_phys_domain(m), domain)); 212 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 213 pmap_zero_page(m); 214 m->valid = VM_PAGE_BITS_ALL; 215 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_RW, 216 VM_PROT_RW | PMAP_ENTER_WIRED, 0); 217 } 218 VM_OBJECT_WUNLOCK(object); 219 return (addr); 220 } 221 222 vm_offset_t 223 kmem_alloc_attr(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 224 vm_memattr_t memattr) 225 { 226 struct vm_domainset_iter di; 227 vm_offset_t addr; 228 int domain; 229 230 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 231 do { 232 addr = kmem_alloc_attr_domain(domain, size, flags, low, high, 233 memattr); 234 if (addr != 0) 235 break; 236 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 237 238 return (addr); 239 } 240 241 /* 242 * Allocates a region from the kernel address map and physically 243 * contiguous pages within the specified address range to the kernel 244 * object. Creates a wired mapping from this region to these pages, and 245 * returns the region's starting virtual address. If M_ZERO is specified 246 * through the given flags, then the pages are zeroed before they are 247 * mapped. 248 */ 249 vm_offset_t 250 kmem_alloc_contig_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 251 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 252 vm_memattr_t memattr) 253 { 254 vmem_t *vmem; 255 vm_object_t object = kernel_object; 256 vm_offset_t addr, offset, tmp; 257 vm_page_t end_m, m; 258 u_long npages; 259 int pflags, tries; 260 261 size = round_page(size); 262 vmem = vm_dom[domain].vmd_kernel_arena; 263 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 264 return (0); 265 offset = addr - VM_MIN_KERNEL_ADDRESS; 266 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 267 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 268 pflags |= VM_ALLOC_NOWAIT; 269 npages = atop(size); 270 VM_OBJECT_WLOCK(object); 271 tries = 0; 272 retry: 273 m = vm_page_alloc_contig_domain(object, atop(offset), domain, pflags, 274 npages, low, high, alignment, boundary, memattr); 275 if (m == NULL) { 276 VM_OBJECT_WUNLOCK(object); 277 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 278 if (!vm_page_reclaim_contig_domain(domain, pflags, 279 npages, low, high, alignment, boundary) && 280 (flags & M_WAITOK) != 0) 281 vm_wait_domain(domain); 282 VM_OBJECT_WLOCK(object); 283 tries++; 284 goto retry; 285 } 286 vmem_free(vmem, addr, size); 287 return (0); 288 } 289 KASSERT(vm_phys_domain(m) == domain, 290 ("kmem_alloc_contig_domain: Domain mismatch %d != %d", 291 vm_phys_domain(m), domain)); 292 end_m = m + npages; 293 tmp = addr; 294 for (; m < end_m; m++) { 295 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 296 pmap_zero_page(m); 297 m->valid = VM_PAGE_BITS_ALL; 298 pmap_enter(kernel_pmap, tmp, m, VM_PROT_RW, 299 VM_PROT_RW | PMAP_ENTER_WIRED, 0); 300 tmp += PAGE_SIZE; 301 } 302 VM_OBJECT_WUNLOCK(object); 303 return (addr); 304 } 305 306 vm_offset_t 307 kmem_alloc_contig(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 308 u_long alignment, vm_paddr_t boundary, vm_memattr_t memattr) 309 { 310 struct vm_domainset_iter di; 311 vm_offset_t addr; 312 int domain; 313 314 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 315 do { 316 addr = kmem_alloc_contig_domain(domain, size, flags, low, high, 317 alignment, boundary, memattr); 318 if (addr != 0) 319 break; 320 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 321 322 return (addr); 323 } 324 325 /* 326 * kmem_suballoc: 327 * 328 * Allocates a map to manage a subrange 329 * of the kernel virtual address space. 330 * 331 * Arguments are as follows: 332 * 333 * parent Map to take range from 334 * min, max Returned endpoints of map 335 * size Size of range to find 336 * superpage_align Request that min is superpage aligned 337 */ 338 vm_map_t 339 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 340 vm_size_t size, boolean_t superpage_align) 341 { 342 int ret; 343 vm_map_t result; 344 345 size = round_page(size); 346 347 *min = vm_map_min(parent); 348 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 349 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 350 MAP_ACC_NO_CHARGE); 351 if (ret != KERN_SUCCESS) 352 panic("kmem_suballoc: bad status return of %d", ret); 353 *max = *min + size; 354 result = vm_map_create(vm_map_pmap(parent), *min, *max); 355 if (result == NULL) 356 panic("kmem_suballoc: cannot create submap"); 357 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 358 panic("kmem_suballoc: unable to change range to submap"); 359 return (result); 360 } 361 362 /* 363 * kmem_malloc: 364 * 365 * Allocate wired-down pages in the kernel's address space. 366 */ 367 vm_offset_t 368 kmem_malloc_domain(int domain, vm_size_t size, int flags) 369 { 370 vmem_t *arena; 371 vm_offset_t addr; 372 int rv; 373 374 #if VM_NRESERVLEVEL > 0 375 if (__predict_true((flags & M_EXEC) == 0)) 376 arena = vm_dom[domain].vmd_kernel_arena; 377 else 378 arena = vm_dom[domain].vmd_kernel_rwx_arena; 379 #else 380 arena = vm_dom[domain].vmd_kernel_arena; 381 #endif 382 size = round_page(size); 383 if (vmem_alloc(arena, size, flags | M_BESTFIT, &addr)) 384 return (0); 385 386 rv = kmem_back_domain(domain, kernel_object, addr, size, flags); 387 if (rv != KERN_SUCCESS) { 388 vmem_free(arena, addr, size); 389 return (0); 390 } 391 return (addr); 392 } 393 394 vm_offset_t 395 kmem_malloc(vm_size_t size, int flags) 396 { 397 struct vm_domainset_iter di; 398 vm_offset_t addr; 399 int domain; 400 401 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 402 do { 403 addr = kmem_malloc_domain(domain, size, flags); 404 if (addr != 0) 405 break; 406 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 407 408 return (addr); 409 } 410 411 /* 412 * kmem_back: 413 * 414 * Allocate physical pages for the specified virtual address range. 415 */ 416 int 417 kmem_back_domain(int domain, vm_object_t object, vm_offset_t addr, 418 vm_size_t size, int flags) 419 { 420 vm_offset_t offset, i; 421 vm_page_t m, mpred; 422 vm_prot_t prot; 423 int pflags; 424 425 KASSERT(object == kernel_object, 426 ("kmem_back_domain: only supports kernel object.")); 427 428 offset = addr - VM_MIN_KERNEL_ADDRESS; 429 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 430 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 431 if (flags & M_WAITOK) 432 pflags |= VM_ALLOC_WAITFAIL; 433 prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW; 434 435 i = 0; 436 VM_OBJECT_WLOCK(object); 437 retry: 438 mpred = vm_radix_lookup_le(&object->rtree, atop(offset + i)); 439 for (; i < size; i += PAGE_SIZE, mpred = m) { 440 m = vm_page_alloc_domain_after(object, atop(offset + i), 441 domain, pflags, mpred); 442 443 /* 444 * Ran out of space, free everything up and return. Don't need 445 * to lock page queues here as we know that the pages we got 446 * aren't on any queues. 447 */ 448 if (m == NULL) { 449 if ((flags & M_NOWAIT) == 0) 450 goto retry; 451 VM_OBJECT_WUNLOCK(object); 452 kmem_unback(object, addr, i); 453 return (KERN_NO_SPACE); 454 } 455 KASSERT(vm_phys_domain(m) == domain, 456 ("kmem_back_domain: Domain mismatch %d != %d", 457 vm_phys_domain(m), domain)); 458 if (flags & M_ZERO && (m->flags & PG_ZERO) == 0) 459 pmap_zero_page(m); 460 KASSERT((m->oflags & VPO_UNMANAGED) != 0, 461 ("kmem_malloc: page %p is managed", m)); 462 m->valid = VM_PAGE_BITS_ALL; 463 pmap_enter(kernel_pmap, addr + i, m, prot, 464 prot | PMAP_ENTER_WIRED, 0); 465 #if VM_NRESERVLEVEL > 0 466 if (__predict_false((prot & VM_PROT_EXECUTE) != 0)) 467 m->oflags |= VPO_KMEM_EXEC; 468 #endif 469 } 470 VM_OBJECT_WUNLOCK(object); 471 472 return (KERN_SUCCESS); 473 } 474 475 int 476 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 477 { 478 struct vm_domainset_iter di; 479 int domain; 480 int ret; 481 482 KASSERT(object == kernel_object, 483 ("kmem_back: only supports kernel object.")); 484 485 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 486 do { 487 ret = kmem_back_domain(domain, object, addr, size, flags); 488 if (ret == KERN_SUCCESS) 489 break; 490 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 491 492 return (ret); 493 } 494 495 /* 496 * kmem_unback: 497 * 498 * Unmap and free the physical pages underlying the specified virtual 499 * address range. 500 * 501 * A physical page must exist within the specified object at each index 502 * that is being unmapped. 503 */ 504 static struct vmem * 505 _kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 506 { 507 struct vmem *arena; 508 vm_page_t m, next; 509 vm_offset_t end, offset; 510 int domain; 511 512 KASSERT(object == kernel_object, 513 ("kmem_unback: only supports kernel object.")); 514 515 if (size == 0) 516 return (NULL); 517 pmap_remove(kernel_pmap, addr, addr + size); 518 offset = addr - VM_MIN_KERNEL_ADDRESS; 519 end = offset + size; 520 VM_OBJECT_WLOCK(object); 521 m = vm_page_lookup(object, atop(offset)); 522 domain = vm_phys_domain(m); 523 #if VM_NRESERVLEVEL > 0 524 if (__predict_true((m->oflags & VPO_KMEM_EXEC) == 0)) 525 arena = vm_dom[domain].vmd_kernel_arena; 526 else 527 arena = vm_dom[domain].vmd_kernel_rwx_arena; 528 #else 529 arena = vm_dom[domain].vmd_kernel_arena; 530 #endif 531 for (; offset < end; offset += PAGE_SIZE, m = next) { 532 next = vm_page_next(m); 533 vm_page_unwire(m, PQ_NONE); 534 vm_page_free(m); 535 } 536 VM_OBJECT_WUNLOCK(object); 537 538 return (arena); 539 } 540 541 void 542 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 543 { 544 545 (void)_kmem_unback(object, addr, size); 546 } 547 548 /* 549 * kmem_free: 550 * 551 * Free memory allocated with kmem_malloc. The size must match the 552 * original allocation. 553 */ 554 void 555 kmem_free(vm_offset_t addr, vm_size_t size) 556 { 557 struct vmem *arena; 558 559 size = round_page(size); 560 arena = _kmem_unback(kernel_object, addr, size); 561 if (arena != NULL) 562 vmem_free(arena, addr, size); 563 } 564 565 /* 566 * kmap_alloc_wait: 567 * 568 * Allocates pageable memory from a sub-map of the kernel. If the submap 569 * has no room, the caller sleeps waiting for more memory in the submap. 570 * 571 * This routine may block. 572 */ 573 vm_offset_t 574 kmap_alloc_wait(vm_map_t map, vm_size_t size) 575 { 576 vm_offset_t addr; 577 578 size = round_page(size); 579 if (!swap_reserve(size)) 580 return (0); 581 582 for (;;) { 583 /* 584 * To make this work for more than one map, use the map's lock 585 * to lock out sleepers/wakers. 586 */ 587 vm_map_lock(map); 588 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0) 589 break; 590 /* no space now; see if we can ever get space */ 591 if (vm_map_max(map) - vm_map_min(map) < size) { 592 vm_map_unlock(map); 593 swap_release(size); 594 return (0); 595 } 596 map->needs_wakeup = TRUE; 597 vm_map_unlock_and_wait(map, 0); 598 } 599 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL, 600 VM_PROT_ALL, MAP_ACC_CHARGED); 601 vm_map_unlock(map); 602 return (addr); 603 } 604 605 /* 606 * kmap_free_wakeup: 607 * 608 * Returns memory to a submap of the kernel, and wakes up any processes 609 * waiting for memory in that map. 610 */ 611 void 612 kmap_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 613 { 614 615 vm_map_lock(map); 616 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 617 if (map->needs_wakeup) { 618 map->needs_wakeup = FALSE; 619 vm_map_wakeup(map); 620 } 621 vm_map_unlock(map); 622 } 623 624 void 625 kmem_init_zero_region(void) 626 { 627 vm_offset_t addr, i; 628 vm_page_t m; 629 630 /* 631 * Map a single physical page of zeros to a larger virtual range. 632 * This requires less looping in places that want large amounts of 633 * zeros, while not using much more physical resources. 634 */ 635 addr = kva_alloc(ZERO_REGION_SIZE); 636 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 637 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 638 if ((m->flags & PG_ZERO) == 0) 639 pmap_zero_page(m); 640 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 641 pmap_qenter(addr + i, &m, 1); 642 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 643 644 zero_region = (const void *)addr; 645 } 646 647 /* 648 * kmem_init: 649 * 650 * Create the kernel map; insert a mapping covering kernel text, 651 * data, bss, and all space allocated thus far (`boostrap' data). The 652 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 653 * `start' as allocated, and the range between `start' and `end' as free. 654 */ 655 void 656 kmem_init(vm_offset_t start, vm_offset_t end) 657 { 658 vm_map_t m; 659 660 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 661 m->system_map = 1; 662 vm_map_lock(m); 663 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 664 kernel_map = m; 665 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 666 #ifdef __amd64__ 667 KERNBASE, 668 #else 669 VM_MIN_KERNEL_ADDRESS, 670 #endif 671 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 672 /* ... and ending with the completion of the above `insert' */ 673 vm_map_unlock(m); 674 } 675 676 /* 677 * kmem_bootstrap_free: 678 * 679 * Free pages backing preloaded data (e.g., kernel modules) to the 680 * system. Currently only supported on platforms that create a 681 * vm_phys segment for preloaded data. 682 */ 683 void 684 kmem_bootstrap_free(vm_offset_t start, vm_size_t size) 685 { 686 #if defined(__i386__) || defined(__amd64__) 687 struct vm_domain *vmd; 688 vm_offset_t end, va; 689 vm_paddr_t pa; 690 vm_page_t m; 691 692 end = trunc_page(start + size); 693 start = round_page(start); 694 695 for (va = start; va < end; va += PAGE_SIZE) { 696 pa = pmap_kextract(va); 697 m = PHYS_TO_VM_PAGE(pa); 698 699 vmd = vm_pagequeue_domain(m); 700 vm_domain_free_lock(vmd); 701 vm_phys_free_pages(m, 0); 702 vmd->vmd_page_count++; 703 vm_domain_free_unlock(vmd); 704 705 vm_domain_freecnt_inc(vmd, 1); 706 vm_cnt.v_page_count++; 707 } 708 pmap_remove(kernel_pmap, start, end); 709 (void)vmem_add(kernel_arena, start, end - start, M_WAITOK); 710 #endif 711 } 712 713 #ifdef DIAGNOSTIC 714 /* 715 * Allow userspace to directly trigger the VM drain routine for testing 716 * purposes. 717 */ 718 static int 719 debug_vm_lowmem(SYSCTL_HANDLER_ARGS) 720 { 721 int error, i; 722 723 i = 0; 724 error = sysctl_handle_int(oidp, &i, 0, req); 725 if (error) 726 return (error); 727 if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0) 728 return (EINVAL); 729 if (i != 0) 730 EVENTHANDLER_INVOKE(vm_lowmem, i); 731 return (0); 732 } 733 734 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0, 735 debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags"); 736 #endif 737