1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 39 * 40 * Permission to use, copy, modify and distribute this software and 41 * its documentation is hereby granted, provided that both the copyright 42 * notice and this permission notice appear in all copies of the 43 * software, derivative works or modified versions, and any portions 44 * thereof, and that both notices appear in supporting documentation. 45 * 46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 49 * 50 * Carnegie Mellon requests users of this software to return to 51 * 52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 53 * School of Computer Science 54 * Carnegie Mellon University 55 * Pittsburgh PA 15213-3890 56 * 57 * any improvements or extensions that they make and grant Carnegie the 58 * rights to redistribute these changes. 59 */ 60 61 /* 62 * Kernel memory management. 63 */ 64 65 #include <sys/cdefs.h> 66 __FBSDID("$FreeBSD$"); 67 68 #include <sys/param.h> 69 #include <sys/systm.h> 70 #include <sys/kernel.h> /* for ticks and hz */ 71 #include <sys/eventhandler.h> 72 #include <sys/lock.h> 73 #include <sys/proc.h> 74 #include <sys/malloc.h> 75 #include <sys/rwlock.h> 76 #include <sys/sysctl.h> 77 #include <sys/vmem.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <vm/vm_kern.h> 82 #include <vm/pmap.h> 83 #include <vm/vm_map.h> 84 #include <vm/vm_object.h> 85 #include <vm/vm_page.h> 86 #include <vm/vm_pageout.h> 87 #include <vm/vm_extern.h> 88 #include <vm/uma.h> 89 90 vm_map_t kernel_map; 91 vm_map_t exec_map; 92 vm_map_t pipe_map; 93 94 const void *zero_region; 95 CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0); 96 97 /* NB: Used by kernel debuggers. */ 98 const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS; 99 100 u_int exec_map_entry_size; 101 u_int exec_map_entries; 102 103 SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD, 104 SYSCTL_NULL_ULONG_PTR, VM_MIN_KERNEL_ADDRESS, "Min kernel address"); 105 106 SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD, 107 #if defined(__arm__) || defined(__sparc64__) 108 &vm_max_kernel_address, 0, 109 #else 110 SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS, 111 #endif 112 "Max kernel address"); 113 114 /* 115 * kva_alloc: 116 * 117 * Allocate a virtual address range with no underlying object and 118 * no initial mapping to physical memory. Any mapping from this 119 * range to physical memory must be explicitly created prior to 120 * its use, typically with pmap_qenter(). Any attempt to create 121 * a mapping on demand through vm_fault() will result in a panic. 122 */ 123 vm_offset_t 124 kva_alloc(size) 125 vm_size_t size; 126 { 127 vm_offset_t addr; 128 129 size = round_page(size); 130 if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr)) 131 return (0); 132 133 return (addr); 134 } 135 136 /* 137 * kva_free: 138 * 139 * Release a region of kernel virtual memory allocated 140 * with kva_alloc, and return the physical pages 141 * associated with that region. 142 * 143 * This routine may not block on kernel maps. 144 */ 145 void 146 kva_free(addr, size) 147 vm_offset_t addr; 148 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 = vmem == kmem_arena ? kmem_object : kernel_object; 168 vm_offset_t addr, i; 169 vm_ooffset_t offset; 170 vm_page_t m; 171 int pflags, tries; 172 173 size = round_page(size); 174 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr)) 175 return (0); 176 offset = addr - VM_MIN_KERNEL_ADDRESS; 177 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 178 VM_OBJECT_WLOCK(object); 179 for (i = 0; i < size; i += PAGE_SIZE) { 180 tries = 0; 181 retry: 182 m = vm_page_alloc_contig(object, OFF_TO_IDX(offset + i), 183 pflags, 1, low, high, PAGE_SIZE, 0, memattr); 184 if (m == NULL) { 185 VM_OBJECT_WUNLOCK(object); 186 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 187 if (!vm_page_reclaim_contig(pflags, 1, 188 low, high, PAGE_SIZE, 0) && 189 (flags & M_WAITOK) != 0) 190 VM_WAIT; 191 VM_OBJECT_WLOCK(object); 192 tries++; 193 goto retry; 194 } 195 kmem_unback(object, addr, i); 196 vmem_free(vmem, addr, size); 197 return (0); 198 } 199 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 200 pmap_zero_page(m); 201 m->valid = VM_PAGE_BITS_ALL; 202 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 203 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 204 } 205 VM_OBJECT_WUNLOCK(object); 206 return (addr); 207 } 208 209 /* 210 * Allocates a region from the kernel address map and physically 211 * contiguous pages within the specified address range to the kernel 212 * object. Creates a wired mapping from this region to these pages, and 213 * returns the region's starting virtual address. If M_ZERO is specified 214 * through the given flags, then the pages are zeroed before they are 215 * mapped. 216 */ 217 vm_offset_t 218 kmem_alloc_contig(struct vmem *vmem, vm_size_t size, int flags, vm_paddr_t low, 219 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 220 vm_memattr_t memattr) 221 { 222 vm_object_t object = vmem == kmem_arena ? kmem_object : kernel_object; 223 vm_offset_t addr, tmp; 224 vm_ooffset_t offset; 225 vm_page_t end_m, m; 226 u_long npages; 227 int pflags, tries; 228 229 size = round_page(size); 230 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 231 return (0); 232 offset = addr - VM_MIN_KERNEL_ADDRESS; 233 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 234 npages = atop(size); 235 VM_OBJECT_WLOCK(object); 236 tries = 0; 237 retry: 238 m = vm_page_alloc_contig(object, OFF_TO_IDX(offset), pflags, 239 npages, low, high, alignment, boundary, memattr); 240 if (m == NULL) { 241 VM_OBJECT_WUNLOCK(object); 242 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 243 if (!vm_page_reclaim_contig(pflags, npages, low, high, 244 alignment, boundary) && (flags & M_WAITOK) != 0) 245 VM_WAIT; 246 VM_OBJECT_WLOCK(object); 247 tries++; 248 goto retry; 249 } 250 vmem_free(vmem, addr, size); 251 return (0); 252 } 253 end_m = m + npages; 254 tmp = addr; 255 for (; m < end_m; m++) { 256 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 257 pmap_zero_page(m); 258 m->valid = VM_PAGE_BITS_ALL; 259 pmap_enter(kernel_pmap, tmp, m, VM_PROT_ALL, 260 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 261 tmp += PAGE_SIZE; 262 } 263 VM_OBJECT_WUNLOCK(object); 264 return (addr); 265 } 266 267 /* 268 * kmem_suballoc: 269 * 270 * Allocates a map to manage a subrange 271 * of the kernel virtual address space. 272 * 273 * Arguments are as follows: 274 * 275 * parent Map to take range from 276 * min, max Returned endpoints of map 277 * size Size of range to find 278 * superpage_align Request that min is superpage aligned 279 */ 280 vm_map_t 281 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 282 vm_size_t size, boolean_t superpage_align) 283 { 284 int ret; 285 vm_map_t result; 286 287 size = round_page(size); 288 289 *min = vm_map_min(parent); 290 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 291 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 292 MAP_ACC_NO_CHARGE); 293 if (ret != KERN_SUCCESS) 294 panic("kmem_suballoc: bad status return of %d", ret); 295 *max = *min + size; 296 result = vm_map_create(vm_map_pmap(parent), *min, *max); 297 if (result == NULL) 298 panic("kmem_suballoc: cannot create submap"); 299 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 300 panic("kmem_suballoc: unable to change range to submap"); 301 return (result); 302 } 303 304 /* 305 * kmem_malloc: 306 * 307 * Allocate wired-down pages in the kernel's address space. 308 */ 309 vm_offset_t 310 kmem_malloc(struct vmem *vmem, vm_size_t size, int flags) 311 { 312 vm_offset_t addr; 313 int rv; 314 315 size = round_page(size); 316 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 317 return (0); 318 319 rv = kmem_back((vmem == kmem_arena) ? kmem_object : kernel_object, 320 addr, size, flags); 321 if (rv != KERN_SUCCESS) { 322 vmem_free(vmem, addr, size); 323 return (0); 324 } 325 return (addr); 326 } 327 328 /* 329 * kmem_back: 330 * 331 * Allocate physical pages for the specified virtual address range. 332 */ 333 int 334 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 335 { 336 vm_offset_t offset, i; 337 vm_page_t m; 338 int pflags; 339 340 KASSERT(object == kmem_object || object == kernel_object, 341 ("kmem_back: only supports kernel objects.")); 342 343 offset = addr - VM_MIN_KERNEL_ADDRESS; 344 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 345 346 VM_OBJECT_WLOCK(object); 347 for (i = 0; i < size; i += PAGE_SIZE) { 348 retry: 349 m = vm_page_alloc(object, OFF_TO_IDX(offset + i), pflags); 350 351 /* 352 * Ran out of space, free everything up and return. Don't need 353 * to lock page queues here as we know that the pages we got 354 * aren't on any queues. 355 */ 356 if (m == NULL) { 357 VM_OBJECT_WUNLOCK(object); 358 if ((flags & M_NOWAIT) == 0) { 359 VM_WAIT; 360 VM_OBJECT_WLOCK(object); 361 goto retry; 362 } 363 kmem_unback(object, addr, i); 364 return (KERN_NO_SPACE); 365 } 366 if (flags & M_ZERO && (m->flags & PG_ZERO) == 0) 367 pmap_zero_page(m); 368 KASSERT((m->oflags & VPO_UNMANAGED) != 0, 369 ("kmem_malloc: page %p is managed", m)); 370 m->valid = VM_PAGE_BITS_ALL; 371 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 372 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 373 } 374 VM_OBJECT_WUNLOCK(object); 375 376 return (KERN_SUCCESS); 377 } 378 379 /* 380 * kmem_unback: 381 * 382 * Unmap and free the physical pages underlying the specified virtual 383 * address range. 384 * 385 * A physical page must exist within the specified object at each index 386 * that is being unmapped. 387 */ 388 void 389 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 390 { 391 vm_page_t m; 392 vm_offset_t i, offset; 393 394 KASSERT(object == kmem_object || object == kernel_object, 395 ("kmem_unback: only supports kernel objects.")); 396 397 pmap_remove(kernel_pmap, addr, addr + size); 398 offset = addr - VM_MIN_KERNEL_ADDRESS; 399 VM_OBJECT_WLOCK(object); 400 for (i = 0; i < size; i += PAGE_SIZE) { 401 m = vm_page_lookup(object, OFF_TO_IDX(offset + i)); 402 vm_page_unwire(m, PQ_NONE); 403 vm_page_free(m); 404 } 405 VM_OBJECT_WUNLOCK(object); 406 } 407 408 /* 409 * kmem_free: 410 * 411 * Free memory allocated with kmem_malloc. The size must match the 412 * original allocation. 413 */ 414 void 415 kmem_free(struct vmem *vmem, vm_offset_t addr, vm_size_t size) 416 { 417 418 size = round_page(size); 419 kmem_unback((vmem == kmem_arena) ? kmem_object : kernel_object, 420 addr, size); 421 vmem_free(vmem, addr, size); 422 } 423 424 /* 425 * kmap_alloc_wait: 426 * 427 * Allocates pageable memory from a sub-map of the kernel. If the submap 428 * has no room, the caller sleeps waiting for more memory in the submap. 429 * 430 * This routine may block. 431 */ 432 vm_offset_t 433 kmap_alloc_wait(map, size) 434 vm_map_t map; 435 vm_size_t size; 436 { 437 vm_offset_t addr; 438 439 size = round_page(size); 440 if (!swap_reserve(size)) 441 return (0); 442 443 for (;;) { 444 /* 445 * To make this work for more than one map, use the map's lock 446 * to lock out sleepers/wakers. 447 */ 448 vm_map_lock(map); 449 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0) 450 break; 451 /* no space now; see if we can ever get space */ 452 if (vm_map_max(map) - vm_map_min(map) < size) { 453 vm_map_unlock(map); 454 swap_release(size); 455 return (0); 456 } 457 map->needs_wakeup = TRUE; 458 vm_map_unlock_and_wait(map, 0); 459 } 460 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL, 461 VM_PROT_ALL, MAP_ACC_CHARGED); 462 vm_map_unlock(map); 463 return (addr); 464 } 465 466 /* 467 * kmap_free_wakeup: 468 * 469 * Returns memory to a submap of the kernel, and wakes up any processes 470 * waiting for memory in that map. 471 */ 472 void 473 kmap_free_wakeup(map, addr, size) 474 vm_map_t map; 475 vm_offset_t addr; 476 vm_size_t size; 477 { 478 479 vm_map_lock(map); 480 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 481 if (map->needs_wakeup) { 482 map->needs_wakeup = FALSE; 483 vm_map_wakeup(map); 484 } 485 vm_map_unlock(map); 486 } 487 488 void 489 kmem_init_zero_region(void) 490 { 491 vm_offset_t addr, i; 492 vm_page_t m; 493 494 /* 495 * Map a single physical page of zeros to a larger virtual range. 496 * This requires less looping in places that want large amounts of 497 * zeros, while not using much more physical resources. 498 */ 499 addr = kva_alloc(ZERO_REGION_SIZE); 500 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 501 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 502 if ((m->flags & PG_ZERO) == 0) 503 pmap_zero_page(m); 504 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 505 pmap_qenter(addr + i, &m, 1); 506 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 507 508 zero_region = (const void *)addr; 509 } 510 511 /* 512 * kmem_init: 513 * 514 * Create the kernel map; insert a mapping covering kernel text, 515 * data, bss, and all space allocated thus far (`boostrap' data). The 516 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 517 * `start' as allocated, and the range between `start' and `end' as free. 518 */ 519 void 520 kmem_init(start, end) 521 vm_offset_t start, end; 522 { 523 vm_map_t m; 524 525 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 526 m->system_map = 1; 527 vm_map_lock(m); 528 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 529 kernel_map = m; 530 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 531 #ifdef __amd64__ 532 KERNBASE, 533 #else 534 VM_MIN_KERNEL_ADDRESS, 535 #endif 536 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 537 /* ... and ending with the completion of the above `insert' */ 538 vm_map_unlock(m); 539 } 540 541 #ifdef DIAGNOSTIC 542 /* 543 * Allow userspace to directly trigger the VM drain routine for testing 544 * purposes. 545 */ 546 static int 547 debug_vm_lowmem(SYSCTL_HANDLER_ARGS) 548 { 549 int error, i; 550 551 i = 0; 552 error = sysctl_handle_int(oidp, &i, 0, req); 553 if (error) 554 return (error); 555 if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0) 556 return (EINVAL); 557 if (i != 0) 558 EVENTHANDLER_INVOKE(vm_lowmem, i); 559 return (0); 560 } 561 562 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0, 563 debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags"); 564 #endif 565