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