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 <sys/param.h> 71 #include <sys/systm.h> 72 #include <sys/kernel.h> /* for ticks and hz */ 73 #include <sys/eventhandler.h> 74 #include <sys/lock.h> 75 #include <sys/proc.h> 76 #include <sys/malloc.h> 77 #include <sys/rwlock.h> 78 #include <sys/sysctl.h> 79 #include <sys/vmem.h> 80 81 #include <vm/vm.h> 82 #include <vm/vm_param.h> 83 #include <vm/vm_kern.h> 84 #include <vm/pmap.h> 85 #include <vm/vm_map.h> 86 #include <vm/vm_object.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_pageout.h> 89 #include <vm/vm_radix.h> 90 #include <vm/vm_extern.h> 91 #include <vm/uma.h> 92 93 vm_map_t kernel_map; 94 vm_map_t exec_map; 95 vm_map_t pipe_map; 96 97 const void *zero_region; 98 CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0); 99 100 /* NB: Used by kernel debuggers. */ 101 const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS; 102 103 u_int exec_map_entry_size; 104 u_int exec_map_entries; 105 106 SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD, 107 SYSCTL_NULL_ULONG_PTR, VM_MIN_KERNEL_ADDRESS, "Min kernel address"); 108 109 SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD, 110 #if defined(__arm__) || defined(__sparc64__) 111 &vm_max_kernel_address, 0, 112 #else 113 SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS, 114 #endif 115 "Max kernel address"); 116 117 /* 118 * kva_alloc: 119 * 120 * Allocate a virtual address range with no underlying object and 121 * no initial mapping to physical memory. Any mapping from this 122 * range to physical memory must be explicitly created prior to 123 * its use, typically with pmap_qenter(). Any attempt to create 124 * a mapping on demand through vm_fault() will result in a panic. 125 */ 126 vm_offset_t 127 kva_alloc(vm_size_t size) 128 { 129 vm_offset_t addr; 130 131 size = round_page(size); 132 if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr)) 133 return (0); 134 135 return (addr); 136 } 137 138 /* 139 * kva_free: 140 * 141 * Release a region of kernel virtual memory allocated 142 * with kva_alloc, and return the physical pages 143 * associated with that region. 144 * 145 * This routine may not block on kernel maps. 146 */ 147 void 148 kva_free(vm_offset_t addr, vm_size_t size) 149 { 150 151 size = round_page(size); 152 vmem_free(kernel_arena, addr, size); 153 } 154 155 /* 156 * Allocates a region from the kernel address map and physical pages 157 * within the specified address range to the kernel object. Creates a 158 * wired mapping from this region to these pages, and returns the 159 * region's starting virtual address. The allocated pages are not 160 * necessarily physically contiguous. If M_ZERO is specified through the 161 * given flags, then the pages are zeroed before they are mapped. 162 */ 163 vm_offset_t 164 kmem_alloc_attr(vmem_t *vmem, vm_size_t size, int flags, vm_paddr_t low, 165 vm_paddr_t high, vm_memattr_t memattr) 166 { 167 vm_object_t object = kernel_object; 168 vm_offset_t addr, i, offset; 169 vm_page_t m; 170 int pflags, tries; 171 172 KASSERT(vmem == kernel_arena, 173 ("kmem_alloc_attr: Only kernel_arena is supported.")); 174 size = round_page(size); 175 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr)) 176 return (0); 177 offset = addr - VM_MIN_KERNEL_ADDRESS; 178 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 179 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 180 pflags |= VM_ALLOC_NOWAIT; 181 VM_OBJECT_WLOCK(object); 182 for (i = 0; i < size; i += PAGE_SIZE) { 183 tries = 0; 184 retry: 185 m = vm_page_alloc_contig(object, atop(offset + i), 186 pflags, 1, low, high, PAGE_SIZE, 0, memattr); 187 if (m == NULL) { 188 VM_OBJECT_WUNLOCK(object); 189 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 190 if (!vm_page_reclaim_contig(pflags, 1, 191 low, high, PAGE_SIZE, 0) && 192 (flags & M_WAITOK) != 0) 193 VM_WAIT; 194 VM_OBJECT_WLOCK(object); 195 tries++; 196 goto retry; 197 } 198 kmem_unback(object, addr, i); 199 vmem_free(vmem, addr, size); 200 return (0); 201 } 202 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 203 pmap_zero_page(m); 204 m->valid = VM_PAGE_BITS_ALL; 205 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 206 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 207 } 208 VM_OBJECT_WUNLOCK(object); 209 return (addr); 210 } 211 212 /* 213 * Allocates a region from the kernel address map and physically 214 * contiguous pages within the specified address range to the kernel 215 * object. Creates a wired mapping from this region to these pages, and 216 * returns the region's starting virtual address. If M_ZERO is specified 217 * through the given flags, then the pages are zeroed before they are 218 * mapped. 219 */ 220 vm_offset_t 221 kmem_alloc_contig(struct vmem *vmem, vm_size_t size, int flags, vm_paddr_t low, 222 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 223 vm_memattr_t memattr) 224 { 225 vm_object_t object = kernel_object; 226 vm_offset_t addr, offset, tmp; 227 vm_page_t end_m, m; 228 u_long npages; 229 int pflags, tries; 230 231 KASSERT(vmem == kernel_arena, 232 ("kmem_alloc_contig: Only kernel_arena is supported.")); 233 size = round_page(size); 234 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 235 return (0); 236 offset = addr - VM_MIN_KERNEL_ADDRESS; 237 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 238 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 239 pflags |= VM_ALLOC_NOWAIT; 240 npages = atop(size); 241 VM_OBJECT_WLOCK(object); 242 tries = 0; 243 retry: 244 m = vm_page_alloc_contig(object, atop(offset), pflags, 245 npages, low, high, alignment, boundary, memattr); 246 if (m == NULL) { 247 VM_OBJECT_WUNLOCK(object); 248 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 249 if (!vm_page_reclaim_contig(pflags, npages, low, high, 250 alignment, boundary) && (flags & M_WAITOK) != 0) 251 VM_WAIT; 252 VM_OBJECT_WLOCK(object); 253 tries++; 254 goto retry; 255 } 256 vmem_free(vmem, addr, size); 257 return (0); 258 } 259 end_m = m + npages; 260 tmp = addr; 261 for (; m < end_m; m++) { 262 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 263 pmap_zero_page(m); 264 m->valid = VM_PAGE_BITS_ALL; 265 pmap_enter(kernel_pmap, tmp, m, VM_PROT_ALL, 266 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 267 tmp += PAGE_SIZE; 268 } 269 VM_OBJECT_WUNLOCK(object); 270 return (addr); 271 } 272 273 /* 274 * kmem_suballoc: 275 * 276 * Allocates a map to manage a subrange 277 * of the kernel virtual address space. 278 * 279 * Arguments are as follows: 280 * 281 * parent Map to take range from 282 * min, max Returned endpoints of map 283 * size Size of range to find 284 * superpage_align Request that min is superpage aligned 285 */ 286 vm_map_t 287 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 288 vm_size_t size, boolean_t superpage_align) 289 { 290 int ret; 291 vm_map_t result; 292 293 size = round_page(size); 294 295 *min = vm_map_min(parent); 296 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 297 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 298 MAP_ACC_NO_CHARGE); 299 if (ret != KERN_SUCCESS) 300 panic("kmem_suballoc: bad status return of %d", ret); 301 *max = *min + size; 302 result = vm_map_create(vm_map_pmap(parent), *min, *max); 303 if (result == NULL) 304 panic("kmem_suballoc: cannot create submap"); 305 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 306 panic("kmem_suballoc: unable to change range to submap"); 307 return (result); 308 } 309 310 /* 311 * kmem_malloc: 312 * 313 * Allocate wired-down pages in the kernel's address space. 314 */ 315 vm_offset_t 316 kmem_malloc(struct vmem *vmem, vm_size_t size, int flags) 317 { 318 vm_offset_t addr; 319 int rv; 320 321 KASSERT(vmem == kernel_arena, 322 ("kmem_malloc: Only kernel_arena is supported.")); 323 size = round_page(size); 324 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 325 return (0); 326 327 rv = kmem_back(kernel_object, addr, size, flags); 328 if (rv != KERN_SUCCESS) { 329 vmem_free(vmem, addr, size); 330 return (0); 331 } 332 return (addr); 333 } 334 335 /* 336 * kmem_back: 337 * 338 * Allocate physical pages for the specified virtual address range. 339 */ 340 int 341 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 342 { 343 vm_offset_t offset, i; 344 vm_page_t m, mpred; 345 int pflags; 346 347 KASSERT(object == kernel_object, 348 ("kmem_back: only supports kernel object.")); 349 350 offset = addr - VM_MIN_KERNEL_ADDRESS; 351 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 352 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 353 if (flags & M_WAITOK) 354 pflags |= VM_ALLOC_WAITFAIL; 355 356 i = 0; 357 VM_OBJECT_WLOCK(object); 358 retry: 359 mpred = vm_radix_lookup_le(&object->rtree, atop(offset + i)); 360 for (; i < size; i += PAGE_SIZE, mpred = m) { 361 m = vm_page_alloc_after(object, atop(offset + i), pflags, 362 mpred); 363 364 /* 365 * Ran out of space, free everything up and return. Don't need 366 * to lock page queues here as we know that the pages we got 367 * aren't on any queues. 368 */ 369 if (m == NULL) { 370 if ((flags & M_NOWAIT) == 0) 371 goto retry; 372 VM_OBJECT_WUNLOCK(object); 373 kmem_unback(object, addr, i); 374 return (KERN_NO_SPACE); 375 } 376 if (flags & M_ZERO && (m->flags & PG_ZERO) == 0) 377 pmap_zero_page(m); 378 KASSERT((m->oflags & VPO_UNMANAGED) != 0, 379 ("kmem_malloc: page %p is managed", m)); 380 m->valid = VM_PAGE_BITS_ALL; 381 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 382 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 383 } 384 VM_OBJECT_WUNLOCK(object); 385 386 return (KERN_SUCCESS); 387 } 388 389 /* 390 * kmem_unback: 391 * 392 * Unmap and free the physical pages underlying the specified virtual 393 * address range. 394 * 395 * A physical page must exist within the specified object at each index 396 * that is being unmapped. 397 */ 398 void 399 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 400 { 401 vm_page_t m, next; 402 vm_offset_t end, offset; 403 404 KASSERT(object == kernel_object, 405 ("kmem_unback: only supports kernel object.")); 406 407 pmap_remove(kernel_pmap, addr, addr + size); 408 offset = addr - VM_MIN_KERNEL_ADDRESS; 409 end = offset + size; 410 VM_OBJECT_WLOCK(object); 411 for (m = vm_page_lookup(object, atop(offset)); offset < end; 412 offset += PAGE_SIZE, m = next) { 413 next = vm_page_next(m); 414 vm_page_unwire(m, PQ_NONE); 415 vm_page_free(m); 416 } 417 VM_OBJECT_WUNLOCK(object); 418 } 419 420 /* 421 * kmem_free: 422 * 423 * Free memory allocated with kmem_malloc. The size must match the 424 * original allocation. 425 */ 426 void 427 kmem_free(struct vmem *vmem, vm_offset_t addr, vm_size_t size) 428 { 429 430 KASSERT(vmem == kernel_arena, 431 ("kmem_free: Only kernel_arena is supported.")); 432 size = round_page(size); 433 kmem_unback(kernel_object, addr, size); 434 vmem_free(vmem, addr, size); 435 } 436 437 /* 438 * kmap_alloc_wait: 439 * 440 * Allocates pageable memory from a sub-map of the kernel. If the submap 441 * has no room, the caller sleeps waiting for more memory in the submap. 442 * 443 * This routine may block. 444 */ 445 vm_offset_t 446 kmap_alloc_wait(vm_map_t map, vm_size_t size) 447 { 448 vm_offset_t addr; 449 450 size = round_page(size); 451 if (!swap_reserve(size)) 452 return (0); 453 454 for (;;) { 455 /* 456 * To make this work for more than one map, use the map's lock 457 * to lock out sleepers/wakers. 458 */ 459 vm_map_lock(map); 460 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0) 461 break; 462 /* no space now; see if we can ever get space */ 463 if (vm_map_max(map) - vm_map_min(map) < size) { 464 vm_map_unlock(map); 465 swap_release(size); 466 return (0); 467 } 468 map->needs_wakeup = TRUE; 469 vm_map_unlock_and_wait(map, 0); 470 } 471 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL, 472 VM_PROT_ALL, MAP_ACC_CHARGED); 473 vm_map_unlock(map); 474 return (addr); 475 } 476 477 /* 478 * kmap_free_wakeup: 479 * 480 * Returns memory to a submap of the kernel, and wakes up any processes 481 * waiting for memory in that map. 482 */ 483 void 484 kmap_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 485 { 486 487 vm_map_lock(map); 488 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 489 if (map->needs_wakeup) { 490 map->needs_wakeup = FALSE; 491 vm_map_wakeup(map); 492 } 493 vm_map_unlock(map); 494 } 495 496 void 497 kmem_init_zero_region(void) 498 { 499 vm_offset_t addr, i; 500 vm_page_t m; 501 502 /* 503 * Map a single physical page of zeros to a larger virtual range. 504 * This requires less looping in places that want large amounts of 505 * zeros, while not using much more physical resources. 506 */ 507 addr = kva_alloc(ZERO_REGION_SIZE); 508 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 509 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 510 if ((m->flags & PG_ZERO) == 0) 511 pmap_zero_page(m); 512 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 513 pmap_qenter(addr + i, &m, 1); 514 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 515 516 zero_region = (const void *)addr; 517 } 518 519 /* 520 * kmem_init: 521 * 522 * Create the kernel map; insert a mapping covering kernel text, 523 * data, bss, and all space allocated thus far (`boostrap' data). The 524 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 525 * `start' as allocated, and the range between `start' and `end' as free. 526 */ 527 void 528 kmem_init(vm_offset_t start, vm_offset_t end) 529 { 530 vm_map_t m; 531 532 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 533 m->system_map = 1; 534 vm_map_lock(m); 535 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 536 kernel_map = m; 537 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 538 #ifdef __amd64__ 539 KERNBASE, 540 #else 541 VM_MIN_KERNEL_ADDRESS, 542 #endif 543 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 544 /* ... and ending with the completion of the above `insert' */ 545 vm_map_unlock(m); 546 } 547 548 #ifdef DIAGNOSTIC 549 /* 550 * Allow userspace to directly trigger the VM drain routine for testing 551 * purposes. 552 */ 553 static int 554 debug_vm_lowmem(SYSCTL_HANDLER_ARGS) 555 { 556 int error, i; 557 558 i = 0; 559 error = sysctl_handle_int(oidp, &i, 0, req); 560 if (error) 561 return (error); 562 if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0) 563 return (EINVAL); 564 if (i != 0) 565 EVENTHANDLER_INVOKE(vm_lowmem, i); 566 return (0); 567 } 568 569 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0, 570 debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags"); 571 #endif 572