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