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