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_radix.h> 96 #include <vm/vm_extern.h> 97 #include <vm/uma.h> 98 99 vm_map_t kernel_map; 100 vm_map_t exec_map; 101 vm_map_t pipe_map; 102 103 const void *zero_region; 104 CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0); 105 106 /* NB: Used by kernel debuggers. */ 107 const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS; 108 109 u_int exec_map_entry_size; 110 u_int exec_map_entries; 111 112 SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD, 113 SYSCTL_NULL_ULONG_PTR, VM_MIN_KERNEL_ADDRESS, "Min kernel address"); 114 115 SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD, 116 #if defined(__arm__) || defined(__sparc64__) 117 &vm_max_kernel_address, 0, 118 #else 119 SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS, 120 #endif 121 "Max kernel address"); 122 123 /* 124 * kva_alloc: 125 * 126 * Allocate a virtual address range with no underlying object and 127 * no initial mapping to physical memory. Any mapping from this 128 * range to physical memory must be explicitly created prior to 129 * its use, typically with pmap_qenter(). Any attempt to create 130 * a mapping on demand through vm_fault() will result in a panic. 131 */ 132 vm_offset_t 133 kva_alloc(vm_size_t size) 134 { 135 vm_offset_t addr; 136 137 size = round_page(size); 138 if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr)) 139 return (0); 140 141 return (addr); 142 } 143 144 /* 145 * kva_free: 146 * 147 * Release a region of kernel virtual memory allocated 148 * with kva_alloc, and return the physical pages 149 * associated with that region. 150 * 151 * This routine may not block on kernel maps. 152 */ 153 void 154 kva_free(vm_offset_t addr, vm_size_t size) 155 { 156 157 size = round_page(size); 158 vmem_free(kernel_arena, addr, size); 159 } 160 161 /* 162 * Allocates a region from the kernel address map and physical pages 163 * within the specified address range to the kernel object. Creates a 164 * wired mapping from this region to these pages, and returns the 165 * region's starting virtual address. The allocated pages are not 166 * necessarily physically contiguous. If M_ZERO is specified through the 167 * given flags, then the pages are zeroed before they are mapped. 168 */ 169 vm_offset_t 170 kmem_alloc_attr_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 171 vm_paddr_t high, vm_memattr_t memattr) 172 { 173 vmem_t *vmem; 174 vm_object_t object = kernel_object; 175 vm_offset_t addr, i, offset; 176 vm_page_t m; 177 int pflags, tries; 178 179 size = round_page(size); 180 vmem = vm_dom[domain].vmd_kernel_arena; 181 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr)) 182 return (0); 183 offset = addr - VM_MIN_KERNEL_ADDRESS; 184 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 185 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 186 pflags |= VM_ALLOC_NOWAIT; 187 VM_OBJECT_WLOCK(object); 188 for (i = 0; i < size; i += PAGE_SIZE) { 189 tries = 0; 190 retry: 191 m = vm_page_alloc_contig_domain(object, atop(offset + i), 192 domain, pflags, 1, low, high, PAGE_SIZE, 0, memattr); 193 if (m == NULL) { 194 VM_OBJECT_WUNLOCK(object); 195 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 196 if (!vm_page_reclaim_contig_domain(domain, 197 pflags, 1, low, high, PAGE_SIZE, 0) && 198 (flags & M_WAITOK) != 0) 199 VM_WAIT; 200 VM_OBJECT_WLOCK(object); 201 tries++; 202 goto retry; 203 } 204 kmem_unback(object, addr, i); 205 vmem_free(vmem, addr, size); 206 return (0); 207 } 208 KASSERT(vm_phys_domidx(m) == domain, 209 ("kmem_alloc_attr_domain: Domain mismatch %d != %d", 210 vm_phys_domidx(m), domain)); 211 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 212 pmap_zero_page(m); 213 m->valid = VM_PAGE_BITS_ALL; 214 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 215 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 216 } 217 VM_OBJECT_WUNLOCK(object); 218 return (addr); 219 } 220 221 vm_offset_t 222 kmem_alloc_attr(vmem_t *vmem, vm_size_t size, int flags, vm_paddr_t low, 223 vm_paddr_t high, vm_memattr_t memattr) 224 { 225 struct vm_domainset_iter di; 226 vm_offset_t addr; 227 int domain; 228 229 KASSERT(vmem == kernel_arena, 230 ("kmem_alloc_attr: Only kernel_arena is supported.")); 231 232 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 233 do { 234 addr = kmem_alloc_attr_domain(domain, size, flags, low, high, 235 memattr); 236 if (addr != 0) 237 break; 238 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 239 240 return (addr); 241 } 242 243 /* 244 * Allocates a region from the kernel address map and physically 245 * contiguous pages within the specified address range to the kernel 246 * object. Creates a wired mapping from this region to these pages, and 247 * returns the region's starting virtual address. If M_ZERO is specified 248 * through the given flags, then the pages are zeroed before they are 249 * mapped. 250 */ 251 vm_offset_t 252 kmem_alloc_contig_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 253 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 254 vm_memattr_t memattr) 255 { 256 vmem_t *vmem; 257 vm_object_t object = kernel_object; 258 vm_offset_t addr, offset, tmp; 259 vm_page_t end_m, m; 260 u_long npages; 261 int pflags, tries; 262 263 size = round_page(size); 264 vmem = vm_dom[domain].vmd_kernel_arena; 265 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 266 return (0); 267 offset = addr - VM_MIN_KERNEL_ADDRESS; 268 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 269 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 270 pflags |= VM_ALLOC_NOWAIT; 271 npages = atop(size); 272 VM_OBJECT_WLOCK(object); 273 tries = 0; 274 retry: 275 m = vm_page_alloc_contig_domain(object, atop(offset), domain, pflags, 276 npages, low, high, alignment, boundary, memattr); 277 if (m == NULL) { 278 VM_OBJECT_WUNLOCK(object); 279 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 280 if (!vm_page_reclaim_contig_domain(domain, pflags, 281 npages, low, high, alignment, boundary) && 282 (flags & M_WAITOK) != 0) 283 VM_WAIT; 284 VM_OBJECT_WLOCK(object); 285 tries++; 286 goto retry; 287 } 288 vmem_free(vmem, addr, size); 289 return (0); 290 } 291 KASSERT(vm_phys_domidx(m) == domain, 292 ("kmem_alloc_contig_domain: Domain mismatch %d != %d", 293 vm_phys_domidx(m), domain)); 294 end_m = m + npages; 295 tmp = addr; 296 for (; m < end_m; m++) { 297 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 298 pmap_zero_page(m); 299 m->valid = VM_PAGE_BITS_ALL; 300 pmap_enter(kernel_pmap, tmp, m, VM_PROT_ALL, 301 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 302 tmp += PAGE_SIZE; 303 } 304 VM_OBJECT_WUNLOCK(object); 305 return (addr); 306 } 307 308 vm_offset_t 309 kmem_alloc_contig(struct vmem *vmem, vm_size_t size, int flags, vm_paddr_t low, 310 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 311 vm_memattr_t memattr) 312 { 313 struct vm_domainset_iter di; 314 vm_offset_t addr; 315 int domain; 316 317 KASSERT(vmem == kernel_arena, 318 ("kmem_alloc_contig: Only kernel_arena is supported.")); 319 320 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 321 do { 322 addr = kmem_alloc_contig_domain(domain, size, flags, low, high, 323 alignment, boundary, memattr); 324 if (addr != 0) 325 break; 326 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 327 328 return (addr); 329 } 330 331 /* 332 * kmem_suballoc: 333 * 334 * Allocates a map to manage a subrange 335 * of the kernel virtual address space. 336 * 337 * Arguments are as follows: 338 * 339 * parent Map to take range from 340 * min, max Returned endpoints of map 341 * size Size of range to find 342 * superpage_align Request that min is superpage aligned 343 */ 344 vm_map_t 345 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 346 vm_size_t size, boolean_t superpage_align) 347 { 348 int ret; 349 vm_map_t result; 350 351 size = round_page(size); 352 353 *min = vm_map_min(parent); 354 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 355 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 356 MAP_ACC_NO_CHARGE); 357 if (ret != KERN_SUCCESS) 358 panic("kmem_suballoc: bad status return of %d", ret); 359 *max = *min + size; 360 result = vm_map_create(vm_map_pmap(parent), *min, *max); 361 if (result == NULL) 362 panic("kmem_suballoc: cannot create submap"); 363 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 364 panic("kmem_suballoc: unable to change range to submap"); 365 return (result); 366 } 367 368 /* 369 * kmem_malloc: 370 * 371 * Allocate wired-down pages in the kernel's address space. 372 */ 373 vm_offset_t 374 kmem_malloc_domain(int domain, vm_size_t size, int flags) 375 { 376 vmem_t *vmem; 377 vm_offset_t addr; 378 int rv; 379 380 vmem = vm_dom[domain].vmd_kernel_arena; 381 size = round_page(size); 382 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 383 return (0); 384 385 rv = kmem_back_domain(domain, kernel_object, addr, size, flags); 386 if (rv != KERN_SUCCESS) { 387 vmem_free(vmem, addr, size); 388 return (0); 389 } 390 return (addr); 391 } 392 393 vm_offset_t 394 kmem_malloc(struct vmem *vmem, vm_size_t size, int flags) 395 { 396 struct vm_domainset_iter di; 397 vm_offset_t addr; 398 int domain; 399 400 KASSERT(vmem == kernel_arena, 401 ("kmem_malloc: Only kernel_arena is supported.")); 402 403 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 404 do { 405 addr = kmem_malloc_domain(domain, size, flags); 406 if (addr != 0) 407 break; 408 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 409 410 return (addr); 411 } 412 413 /* 414 * kmem_back: 415 * 416 * Allocate physical pages for the specified virtual address range. 417 */ 418 int 419 kmem_back_domain(int domain, vm_object_t object, vm_offset_t addr, 420 vm_size_t size, int flags) 421 { 422 vm_offset_t offset, i; 423 vm_page_t m, mpred; 424 int pflags; 425 426 KASSERT(object == kernel_object, 427 ("kmem_back_domain: only supports kernel object.")); 428 429 offset = addr - VM_MIN_KERNEL_ADDRESS; 430 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 431 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 432 if (flags & M_WAITOK) 433 pflags |= VM_ALLOC_WAITFAIL; 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_domidx(m) == domain, 456 ("kmem_back_domain: Domain mismatch %d != %d", 457 vm_phys_domidx(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, VM_PROT_ALL, 464 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 465 } 466 VM_OBJECT_WUNLOCK(object); 467 468 return (KERN_SUCCESS); 469 } 470 471 int 472 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 473 { 474 struct vm_domainset_iter di; 475 int domain; 476 int ret; 477 478 KASSERT(object == kernel_object, 479 ("kmem_back: only supports kernel object.")); 480 481 vm_domainset_iter_malloc_init(&di, kernel_object, &domain, &flags); 482 do { 483 ret = kmem_back_domain(domain, object, addr, size, flags); 484 if (ret == KERN_SUCCESS) 485 break; 486 } while (vm_domainset_iter_malloc(&di, &domain, &flags) == 0); 487 488 return (ret); 489 } 490 491 /* 492 * kmem_unback: 493 * 494 * Unmap and free the physical pages underlying the specified virtual 495 * address range. 496 * 497 * A physical page must exist within the specified object at each index 498 * that is being unmapped. 499 */ 500 static int 501 _kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 502 { 503 vm_page_t m, next; 504 vm_offset_t end, offset; 505 int domain; 506 507 KASSERT(object == kernel_object, 508 ("kmem_unback: only supports kernel object.")); 509 510 if (size == 0) 511 return (0); 512 pmap_remove(kernel_pmap, addr, addr + size); 513 offset = addr - VM_MIN_KERNEL_ADDRESS; 514 end = offset + size; 515 VM_OBJECT_WLOCK(object); 516 m = vm_page_lookup(object, atop(offset)); 517 domain = vm_phys_domidx(m); 518 for (; offset < end; offset += PAGE_SIZE, m = next) { 519 next = vm_page_next(m); 520 vm_page_unwire(m, PQ_NONE); 521 vm_page_free(m); 522 } 523 VM_OBJECT_WUNLOCK(object); 524 525 return (domain); 526 } 527 528 void 529 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 530 { 531 532 _kmem_unback(object, addr, size); 533 } 534 535 /* 536 * kmem_free: 537 * 538 * Free memory allocated with kmem_malloc. The size must match the 539 * original allocation. 540 */ 541 void 542 kmem_free(struct vmem *vmem, vm_offset_t addr, vm_size_t size) 543 { 544 int domain; 545 546 KASSERT(vmem == kernel_arena, 547 ("kmem_free: Only kernel_arena is supported.")); 548 size = round_page(size); 549 domain = _kmem_unback(kernel_object, addr, size); 550 vmem_free(vm_dom[domain].vmd_kernel_arena, addr, size); 551 } 552 553 /* 554 * kmap_alloc_wait: 555 * 556 * Allocates pageable memory from a sub-map of the kernel. If the submap 557 * has no room, the caller sleeps waiting for more memory in the submap. 558 * 559 * This routine may block. 560 */ 561 vm_offset_t 562 kmap_alloc_wait(vm_map_t map, vm_size_t size) 563 { 564 vm_offset_t addr; 565 566 size = round_page(size); 567 if (!swap_reserve(size)) 568 return (0); 569 570 for (;;) { 571 /* 572 * To make this work for more than one map, use the map's lock 573 * to lock out sleepers/wakers. 574 */ 575 vm_map_lock(map); 576 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0) 577 break; 578 /* no space now; see if we can ever get space */ 579 if (vm_map_max(map) - vm_map_min(map) < size) { 580 vm_map_unlock(map); 581 swap_release(size); 582 return (0); 583 } 584 map->needs_wakeup = TRUE; 585 vm_map_unlock_and_wait(map, 0); 586 } 587 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL, 588 VM_PROT_ALL, MAP_ACC_CHARGED); 589 vm_map_unlock(map); 590 return (addr); 591 } 592 593 /* 594 * kmap_free_wakeup: 595 * 596 * Returns memory to a submap of the kernel, and wakes up any processes 597 * waiting for memory in that map. 598 */ 599 void 600 kmap_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 601 { 602 603 vm_map_lock(map); 604 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 605 if (map->needs_wakeup) { 606 map->needs_wakeup = FALSE; 607 vm_map_wakeup(map); 608 } 609 vm_map_unlock(map); 610 } 611 612 void 613 kmem_init_zero_region(void) 614 { 615 vm_offset_t addr, i; 616 vm_page_t m; 617 618 /* 619 * Map a single physical page of zeros to a larger virtual range. 620 * This requires less looping in places that want large amounts of 621 * zeros, while not using much more physical resources. 622 */ 623 addr = kva_alloc(ZERO_REGION_SIZE); 624 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 625 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 626 if ((m->flags & PG_ZERO) == 0) 627 pmap_zero_page(m); 628 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 629 pmap_qenter(addr + i, &m, 1); 630 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 631 632 zero_region = (const void *)addr; 633 } 634 635 /* 636 * kmem_init: 637 * 638 * Create the kernel map; insert a mapping covering kernel text, 639 * data, bss, and all space allocated thus far (`boostrap' data). The 640 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 641 * `start' as allocated, and the range between `start' and `end' as free. 642 */ 643 void 644 kmem_init(vm_offset_t start, vm_offset_t end) 645 { 646 vm_map_t m; 647 648 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 649 m->system_map = 1; 650 vm_map_lock(m); 651 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 652 kernel_map = m; 653 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 654 #ifdef __amd64__ 655 KERNBASE, 656 #else 657 VM_MIN_KERNEL_ADDRESS, 658 #endif 659 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 660 /* ... and ending with the completion of the above `insert' */ 661 vm_map_unlock(m); 662 } 663 664 #ifdef DIAGNOSTIC 665 /* 666 * Allow userspace to directly trigger the VM drain routine for testing 667 * purposes. 668 */ 669 static int 670 debug_vm_lowmem(SYSCTL_HANDLER_ARGS) 671 { 672 int error, i; 673 674 i = 0; 675 error = sysctl_handle_int(oidp, &i, 0, req); 676 if (error) 677 return (error); 678 if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0) 679 return (EINVAL); 680 if (i != 0) 681 EVENTHANDLER_INVOKE(vm_lowmem, i); 682 return (0); 683 } 684 685 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0, 686 debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags"); 687 #endif 688