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_radix.h> 88 #include <vm/vm_extern.h> 89 #include <vm/uma.h> 90 91 vm_map_t kernel_map; 92 vm_map_t exec_map; 93 vm_map_t pipe_map; 94 95 const void *zero_region; 96 CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0); 97 98 /* NB: Used by kernel debuggers. */ 99 const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS; 100 101 u_int exec_map_entry_size; 102 u_int exec_map_entries; 103 104 SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD, 105 SYSCTL_NULL_ULONG_PTR, VM_MIN_KERNEL_ADDRESS, "Min kernel address"); 106 107 SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD, 108 #if defined(__arm__) || defined(__sparc64__) 109 &vm_max_kernel_address, 0, 110 #else 111 SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS, 112 #endif 113 "Max kernel address"); 114 115 /* 116 * kva_alloc: 117 * 118 * Allocate a virtual address range with no underlying object and 119 * no initial mapping to physical memory. Any mapping from this 120 * range to physical memory must be explicitly created prior to 121 * its use, typically with pmap_qenter(). Any attempt to create 122 * a mapping on demand through vm_fault() will result in a panic. 123 */ 124 vm_offset_t 125 kva_alloc(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(vm_offset_t addr, vm_size_t size) 147 { 148 149 size = round_page(size); 150 vmem_free(kernel_arena, addr, size); 151 } 152 153 /* 154 * Allocates a region from the kernel address map and physical pages 155 * within the specified address range to the kernel object. Creates a 156 * wired mapping from this region to these pages, and returns the 157 * region's starting virtual address. The allocated pages are not 158 * necessarily physically contiguous. If M_ZERO is specified through the 159 * given flags, then the pages are zeroed before they are mapped. 160 */ 161 vm_offset_t 162 kmem_alloc_attr(vmem_t *vmem, vm_size_t size, int flags, vm_paddr_t low, 163 vm_paddr_t high, vm_memattr_t memattr) 164 { 165 vm_object_t object = vmem == kmem_arena ? kmem_object : kernel_object; 166 vm_offset_t addr, i, 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, atop(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 if (!vm_page_reclaim_contig(pflags, 1, 185 low, high, PAGE_SIZE, 0) && 186 (flags & M_WAITOK) != 0) 187 VM_WAIT; 188 VM_OBJECT_WLOCK(object); 189 tries++; 190 goto retry; 191 } 192 kmem_unback(object, addr, i); 193 vmem_free(vmem, addr, size); 194 return (0); 195 } 196 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 197 pmap_zero_page(m); 198 m->valid = VM_PAGE_BITS_ALL; 199 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 200 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 201 } 202 VM_OBJECT_WUNLOCK(object); 203 return (addr); 204 } 205 206 /* 207 * Allocates a region from the kernel address map and physically 208 * contiguous pages within the specified address range to the kernel 209 * object. Creates a wired mapping from this region to these pages, and 210 * returns the region's starting virtual address. If M_ZERO is specified 211 * through the given flags, then the pages are zeroed before they are 212 * mapped. 213 */ 214 vm_offset_t 215 kmem_alloc_contig(struct vmem *vmem, vm_size_t size, int flags, vm_paddr_t low, 216 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 217 vm_memattr_t memattr) 218 { 219 vm_object_t object = vmem == kmem_arena ? kmem_object : kernel_object; 220 vm_offset_t addr, offset, tmp; 221 vm_page_t end_m, m; 222 u_long npages; 223 int pflags, tries; 224 225 size = round_page(size); 226 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 227 return (0); 228 offset = addr - VM_MIN_KERNEL_ADDRESS; 229 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 230 npages = atop(size); 231 VM_OBJECT_WLOCK(object); 232 tries = 0; 233 retry: 234 m = vm_page_alloc_contig(object, atop(offset), pflags, 235 npages, low, high, alignment, boundary, memattr); 236 if (m == NULL) { 237 VM_OBJECT_WUNLOCK(object); 238 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 239 if (!vm_page_reclaim_contig(pflags, npages, low, high, 240 alignment, boundary) && (flags & M_WAITOK) != 0) 241 VM_WAIT; 242 VM_OBJECT_WLOCK(object); 243 tries++; 244 goto retry; 245 } 246 vmem_free(vmem, addr, size); 247 return (0); 248 } 249 end_m = m + npages; 250 tmp = addr; 251 for (; m < end_m; m++) { 252 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 253 pmap_zero_page(m); 254 m->valid = VM_PAGE_BITS_ALL; 255 pmap_enter(kernel_pmap, tmp, m, VM_PROT_ALL, 256 VM_PROT_ALL | PMAP_ENTER_WIRED, 0); 257 tmp += PAGE_SIZE; 258 } 259 VM_OBJECT_WUNLOCK(object); 260 return (addr); 261 } 262 263 /* 264 * kmem_suballoc: 265 * 266 * Allocates a map to manage a subrange 267 * of the kernel virtual address space. 268 * 269 * Arguments are as follows: 270 * 271 * parent Map to take range from 272 * min, max Returned endpoints of map 273 * size Size of range to find 274 * superpage_align Request that min is superpage aligned 275 */ 276 vm_map_t 277 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 278 vm_size_t size, boolean_t superpage_align) 279 { 280 int ret; 281 vm_map_t result; 282 283 size = round_page(size); 284 285 *min = vm_map_min(parent); 286 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 287 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 288 MAP_ACC_NO_CHARGE); 289 if (ret != KERN_SUCCESS) 290 panic("kmem_suballoc: bad status return of %d", ret); 291 *max = *min + size; 292 result = vm_map_create(vm_map_pmap(parent), *min, *max); 293 if (result == NULL) 294 panic("kmem_suballoc: cannot create submap"); 295 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 296 panic("kmem_suballoc: unable to change range to submap"); 297 return (result); 298 } 299 300 /* 301 * kmem_malloc: 302 * 303 * Allocate wired-down pages in the kernel's address space. 304 */ 305 vm_offset_t 306 kmem_malloc(struct vmem *vmem, vm_size_t size, int flags) 307 { 308 vm_offset_t addr; 309 int rv; 310 311 size = round_page(size); 312 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 313 return (0); 314 315 rv = kmem_back((vmem == kmem_arena) ? kmem_object : kernel_object, 316 addr, size, flags); 317 if (rv != KERN_SUCCESS) { 318 vmem_free(vmem, addr, size); 319 return (0); 320 } 321 return (addr); 322 } 323 324 /* 325 * kmem_back: 326 * 327 * Allocate physical pages for the specified virtual address range. 328 */ 329 int 330 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 331 { 332 vm_offset_t offset, i; 333 vm_page_t m, mpred; 334 int pflags; 335 336 KASSERT(object == kmem_object || object == kernel_object, 337 ("kmem_back: only supports kernel objects.")); 338 339 offset = addr - VM_MIN_KERNEL_ADDRESS; 340 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 341 342 i = 0; 343 retry: 344 VM_OBJECT_WLOCK(object); 345 mpred = vm_radix_lookup_le(&object->rtree, atop(offset + i)); 346 for (; i < size; i += PAGE_SIZE, mpred = m) { 347 m = vm_page_alloc_after(object, atop(offset + i), pflags, 348 mpred); 349 350 /* 351 * Ran out of space, free everything up and return. Don't need 352 * to lock page queues here as we know that the pages we got 353 * aren't on any queues. 354 */ 355 if (m == NULL) { 356 VM_OBJECT_WUNLOCK(object); 357 if ((flags & M_NOWAIT) == 0) { 358 VM_WAIT; 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, next; 390 vm_offset_t end, 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 end = offset + size; 398 VM_OBJECT_WLOCK(object); 399 for (m = vm_page_lookup(object, atop(offset)); offset < end; 400 offset += PAGE_SIZE, m = next) { 401 next = vm_page_next(m); 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(vm_map_t map, 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(vm_map_t map, vm_offset_t addr, vm_size_t size) 472 { 473 474 vm_map_lock(map); 475 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 476 if (map->needs_wakeup) { 477 map->needs_wakeup = FALSE; 478 vm_map_wakeup(map); 479 } 480 vm_map_unlock(map); 481 } 482 483 void 484 kmem_init_zero_region(void) 485 { 486 vm_offset_t addr, i; 487 vm_page_t m; 488 489 /* 490 * Map a single physical page of zeros to a larger virtual range. 491 * This requires less looping in places that want large amounts of 492 * zeros, while not using much more physical resources. 493 */ 494 addr = kva_alloc(ZERO_REGION_SIZE); 495 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 496 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 497 if ((m->flags & PG_ZERO) == 0) 498 pmap_zero_page(m); 499 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 500 pmap_qenter(addr + i, &m, 1); 501 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 502 503 zero_region = (const void *)addr; 504 } 505 506 /* 507 * kmem_init: 508 * 509 * Create the kernel map; insert a mapping covering kernel text, 510 * data, bss, and all space allocated thus far (`boostrap' data). The 511 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 512 * `start' as allocated, and the range between `start' and `end' as free. 513 */ 514 void 515 kmem_init(vm_offset_t start, vm_offset_t end) 516 { 517 vm_map_t m; 518 519 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 520 m->system_map = 1; 521 vm_map_lock(m); 522 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 523 kernel_map = m; 524 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 525 #ifdef __amd64__ 526 KERNBASE, 527 #else 528 VM_MIN_KERNEL_ADDRESS, 529 #endif 530 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 531 /* ... and ending with the completion of the above `insert' */ 532 vm_map_unlock(m); 533 } 534 535 #ifdef DIAGNOSTIC 536 /* 537 * Allow userspace to directly trigger the VM drain routine for testing 538 * purposes. 539 */ 540 static int 541 debug_vm_lowmem(SYSCTL_HANDLER_ARGS) 542 { 543 int error, i; 544 545 i = 0; 546 error = sysctl_handle_int(oidp, &i, 0, req); 547 if (error) 548 return (error); 549 if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0) 550 return (EINVAL); 551 if (i != 0) 552 EVENTHANDLER_INVOKE(vm_lowmem, i); 553 return (0); 554 } 555 556 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0, 557 debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags"); 558 #endif 559