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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 43 * 44 * Permission to use, copy, modify and distribute this software and 45 * its documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 * 64 * $FreeBSD: src/sys/vm/vm_kern.c,v 1.61.2.2 2002/03/12 18:25:26 tegge Exp $ 65 * $DragonFly: src/sys/vm/vm_kern.c,v 1.23 2006/09/11 20:25:31 dillon Exp $ 66 */ 67 68 /* 69 * Kernel memory management. 70 */ 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/proc.h> 75 #include <sys/malloc.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_param.h> 79 #include <sys/lock.h> 80 #include <vm/pmap.h> 81 #include <vm/vm_map.h> 82 #include <vm/vm_object.h> 83 #include <vm/vm_page.h> 84 #include <vm/vm_pageout.h> 85 #include <vm/vm_kern.h> 86 #include <vm/vm_extern.h> 87 88 vm_map_t kernel_map=0; 89 vm_map_t exec_map=0; 90 vm_map_t clean_map=0; 91 vm_map_t buffer_map=0; 92 93 /* 94 * kmem_alloc_pageable: 95 * 96 * Allocate pageable memory to the kernel's address map. 97 * "map" must be kernel_map or a submap of kernel_map. 98 */ 99 vm_offset_t 100 kmem_alloc_pageable(vm_map_t map, vm_size_t size) 101 { 102 vm_offset_t addr; 103 int result; 104 105 size = round_page(size); 106 addr = vm_map_min(map); 107 result = vm_map_find(map, NULL, (vm_offset_t) 0, 108 &addr, size, 109 TRUE, 110 VM_MAPTYPE_NORMAL, 111 VM_PROT_ALL, VM_PROT_ALL, 112 0); 113 if (result != KERN_SUCCESS) { 114 return (0); 115 } 116 return (addr); 117 } 118 119 /* 120 * kmem_alloc_nofault: 121 * 122 * Same as kmem_alloc_pageable, except that it create a nofault entry. 123 */ 124 vm_offset_t 125 kmem_alloc_nofault(vm_map_t map, vm_size_t size) 126 { 127 vm_offset_t addr; 128 int result; 129 130 size = round_page(size); 131 addr = vm_map_min(map); 132 result = vm_map_find(map, NULL, (vm_offset_t) 0, 133 &addr, size, 134 TRUE, 135 VM_MAPTYPE_NORMAL, 136 VM_PROT_ALL, VM_PROT_ALL, 137 MAP_NOFAULT); 138 if (result != KERN_SUCCESS) { 139 return (0); 140 } 141 return (addr); 142 } 143 144 /* 145 * Allocate wired-down memory in the kernel's address map 146 * or a submap. 147 */ 148 vm_offset_t 149 kmem_alloc3(vm_map_t map, vm_size_t size, int kmflags) 150 { 151 vm_offset_t addr; 152 vm_offset_t offset; 153 vm_offset_t i; 154 int count; 155 156 size = round_page(size); 157 158 if (kmflags & KM_KRESERVE) 159 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); 160 else 161 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 162 163 /* 164 * Use the kernel object for wired-down kernel pages. Assume that no 165 * region of the kernel object is referenced more than once. 166 * 167 * Locate sufficient space in the map. This will give us the final 168 * virtual address for the new memory, and thus will tell us the 169 * offset within the kernel map. 170 */ 171 vm_map_lock(map); 172 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) { 173 vm_map_unlock(map); 174 if (kmflags & KM_KRESERVE) 175 vm_map_entry_krelease(count); 176 else 177 vm_map_entry_release(count); 178 return (0); 179 } 180 offset = addr - VM_MIN_KERNEL_ADDRESS; 181 vm_object_reference(kernel_object); 182 vm_map_insert(map, &count, 183 kernel_object, offset, addr, addr + size, 184 VM_MAPTYPE_NORMAL, 185 VM_PROT_ALL, VM_PROT_ALL, 186 0); 187 vm_map_unlock(map); 188 if (kmflags & KM_KRESERVE) 189 vm_map_entry_krelease(count); 190 else 191 vm_map_entry_release(count); 192 193 /* 194 * Guarantee that there are pages already in this object before 195 * calling vm_map_wire. This is to prevent the following 196 * scenario: 197 * 198 * 1) Threads have swapped out, so that there is a pager for the 199 * kernel_object. 2) The kmsg zone is empty, and so we are 200 * kmem_allocing a new page for it. 3) vm_map_wire calls vm_fault; 201 * there is no page, but there is a pager, so we call 202 * pager_data_request. But the kmsg zone is empty, so we must 203 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when 204 * we get the data back from the pager, it will be (very stale) 205 * non-zero data. kmem_alloc is defined to return zero-filled memory. 206 * 207 * We're intentionally not activating the pages we allocate to prevent a 208 * race with page-out. vm_map_wire will wire the pages. 209 */ 210 211 for (i = 0; i < size; i += PAGE_SIZE) { 212 vm_page_t mem; 213 214 mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i), 215 VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 216 if ((mem->flags & PG_ZERO) == 0) 217 vm_page_zero_fill(mem); 218 mem->valid = VM_PAGE_BITS_ALL; 219 vm_page_flag_clear(mem, PG_ZERO); 220 vm_page_wakeup(mem); 221 } 222 223 /* 224 * And finally, mark the data as non-pageable. 225 */ 226 227 vm_map_wire(map, (vm_offset_t) addr, addr + size, kmflags); 228 229 return (addr); 230 } 231 232 /* 233 * kmem_free: 234 * 235 * Release a region of kernel virtual memory allocated 236 * with kmem_alloc, and return the physical pages 237 * associated with that region. 238 * 239 * This routine may not block on kernel maps. 240 */ 241 void 242 kmem_free(vm_map_t map, vm_offset_t addr, vm_size_t size) 243 { 244 vm_map_remove(map, trunc_page(addr), round_page(addr + size)); 245 } 246 247 /* 248 * kmem_suballoc: 249 * 250 * Allocates a map to manage a subrange 251 * of the kernel virtual address space. 252 * 253 * Arguments are as follows: 254 * 255 * parent Map to take range from 256 * size Size of range to find 257 * min, max Returned endpoints of map 258 * pageable Can the region be paged 259 */ 260 vm_map_t 261 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 262 vm_size_t size) 263 { 264 int ret; 265 vm_map_t result; 266 267 size = round_page(size); 268 269 *min = (vm_offset_t) vm_map_min(parent); 270 ret = vm_map_find(parent, NULL, (vm_offset_t) 0, 271 min, size, 272 TRUE, 273 VM_MAPTYPE_UNSPECIFIED, 274 VM_PROT_ALL, VM_PROT_ALL, 275 0); 276 if (ret != KERN_SUCCESS) { 277 printf("kmem_suballoc: bad status return of %d.\n", ret); 278 panic("kmem_suballoc"); 279 } 280 *max = *min + size; 281 pmap_reference(vm_map_pmap(parent)); 282 result = vm_map_create(vm_map_pmap(parent), *min, *max); 283 if (result == NULL) 284 panic("kmem_suballoc: cannot create submap"); 285 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS) 286 panic("kmem_suballoc: unable to change range to submap"); 287 return (result); 288 } 289 290 /* 291 * kmem_malloc: 292 * 293 * Allocate wired-down memory in the kernel's address map for the higher 294 * level kernel memory allocator (kern/kern_malloc.c). We cannot use 295 * kmem_alloc() because we may need to allocate memory at interrupt 296 * level where we cannot block (canwait == FALSE). 297 * 298 * We don't worry about expanding the map (adding entries) since entries 299 * for wired maps are statically allocated. 300 * 301 * NOTE: Please see kmem_slab_alloc() for a better explanation of the 302 * M_* flags. 303 */ 304 vm_offset_t 305 kmem_malloc(vm_map_t map, vm_size_t size, int flags) 306 { 307 vm_offset_t offset, i; 308 vm_map_entry_t entry; 309 vm_offset_t addr; 310 vm_page_t m; 311 int count, vmflags, wanted_reserve; 312 thread_t td; 313 314 if (map != kernel_map) 315 panic("kmem_malloc: map != kernel_map"); 316 317 size = round_page(size); 318 addr = vm_map_min(map); 319 320 /* 321 * Locate sufficient space in the map. This will give us the final 322 * virtual address for the new memory, and thus will tell us the 323 * offset within the kernel map. If we are unable to allocate space 324 * and neither RNOWAIT or NULLOK is set, we panic. 325 */ 326 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 327 vm_map_lock(map); 328 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) { 329 vm_map_unlock(map); 330 vm_map_entry_release(count); 331 if ((flags & M_NULLOK) == 0) { 332 panic("kmem_malloc(%ld): kernel_map too small: " 333 "%ld total allocated", 334 (long)size, (long)map->size); 335 } 336 return (0); 337 } 338 offset = addr - VM_MIN_KERNEL_ADDRESS; 339 vm_object_reference(kmem_object); 340 vm_map_insert(map, &count, 341 kmem_object, offset, addr, addr + size, 342 VM_MAPTYPE_NORMAL, 343 VM_PROT_ALL, VM_PROT_ALL, 344 0); 345 346 td = curthread; 347 wanted_reserve = 0; 348 349 vmflags = VM_ALLOC_SYSTEM; /* XXX M_USE_RESERVE? */ 350 if ((flags & (M_WAITOK|M_RNOWAIT)) == 0) 351 panic("kmem_malloc: bad flags %08x (%p)\n", flags, ((int **)&map)[-1]); 352 if (flags & M_USE_INTERRUPT_RESERVE) 353 vmflags |= VM_ALLOC_INTERRUPT; 354 355 for (i = 0; i < size; i += PAGE_SIZE) { 356 /* 357 * Only allocate PQ_CACHE pages for M_WAITOK requests and 358 * then only if we are not preempting. 359 */ 360 if (flags & M_WAITOK) { 361 if (td->td_preempted) { 362 vmflags &= ~VM_ALLOC_NORMAL; 363 wanted_reserve = 1; 364 } else { 365 vmflags |= VM_ALLOC_NORMAL; 366 wanted_reserve = 0; 367 } 368 } 369 370 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i), vmflags); 371 372 /* 373 * Ran out of space, free everything up and return. Don't need 374 * to lock page queues here as we know that the pages we got 375 * aren't on any queues. 376 * 377 * If M_WAITOK is set we can yield or block. 378 */ 379 if (m == NULL) { 380 if (flags & M_WAITOK) { 381 if (wanted_reserve) { 382 vm_map_unlock(map); 383 lwkt_yield(); 384 vm_map_lock(map); 385 } else { 386 vm_map_unlock(map); 387 vm_wait(); 388 vm_map_lock(map); 389 } 390 i -= PAGE_SIZE; /* retry */ 391 continue; 392 } 393 /* 394 * Free the pages before removing the map entry. 395 * They are already marked busy. Calling 396 * vm_map_delete before the pages has been freed or 397 * unbusied will cause a deadlock. 398 */ 399 while (i != 0) { 400 i -= PAGE_SIZE; 401 m = vm_page_lookup(kmem_object, 402 OFF_TO_IDX(offset + i)); 403 vm_page_free(m); 404 } 405 vm_map_delete(map, addr, addr + size, &count); 406 vm_map_unlock(map); 407 vm_map_entry_release(count); 408 return (0); 409 } 410 vm_page_flag_clear(m, PG_ZERO); 411 m->valid = VM_PAGE_BITS_ALL; 412 } 413 414 /* 415 * Mark map entry as non-pageable. Assert: vm_map_insert() will never 416 * be able to extend the previous entry so there will be a new entry 417 * exactly corresponding to this address range and it will have 418 * wired_count == 0. 419 */ 420 if (!vm_map_lookup_entry(map, addr, &entry) || 421 entry->start != addr || entry->end != addr + size || 422 entry->wired_count != 0) 423 panic("kmem_malloc: entry not found or misaligned"); 424 entry->wired_count = 1; 425 426 vm_map_simplify_entry(map, entry, &count); 427 428 /* 429 * Loop thru pages, entering them in the pmap. (We cannot add them to 430 * the wired count without wrapping the vm_page_queue_lock in 431 * splimp...) 432 */ 433 for (i = 0; i < size; i += PAGE_SIZE) { 434 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i)); 435 vm_page_wire(m); 436 vm_page_wakeup(m); 437 /* 438 * Because this is kernel_pmap, this call will not block. 439 */ 440 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1); 441 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED); 442 } 443 vm_map_unlock(map); 444 vm_map_entry_release(count); 445 446 return (addr); 447 } 448 449 /* 450 * kmem_alloc_wait: 451 * 452 * Allocates pageable memory from a sub-map of the kernel. If the submap 453 * has no room, the caller sleeps waiting for more memory in the submap. 454 * 455 * This routine may block. 456 */ 457 458 vm_offset_t 459 kmem_alloc_wait(vm_map_t map, vm_size_t size) 460 { 461 vm_offset_t addr; 462 int count; 463 464 size = round_page(size); 465 466 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 467 468 for (;;) { 469 /* 470 * To make this work for more than one map, use the map's lock 471 * to lock out sleepers/wakers. 472 */ 473 vm_map_lock(map); 474 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr) == 0) 475 break; 476 /* no space now; see if we can ever get space */ 477 if (vm_map_max(map) - vm_map_min(map) < size) { 478 vm_map_entry_release(count); 479 vm_map_unlock(map); 480 return (0); 481 } 482 vm_map_unlock(map); 483 tsleep(map, 0, "kmaw", 0); 484 } 485 vm_map_insert(map, &count, 486 NULL, (vm_offset_t) 0, 487 addr, addr + size, 488 VM_MAPTYPE_NORMAL, 489 VM_PROT_ALL, VM_PROT_ALL, 490 0); 491 vm_map_unlock(map); 492 vm_map_entry_release(count); 493 return (addr); 494 } 495 496 /* 497 * kmem_free_wakeup: 498 * 499 * Returns memory to a submap of the kernel, and wakes up any processes 500 * waiting for memory in that map. 501 */ 502 void 503 kmem_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 504 { 505 int count; 506 507 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 508 vm_map_lock(map); 509 vm_map_delete(map, trunc_page(addr), round_page(addr + size), &count); 510 wakeup(map); 511 vm_map_unlock(map); 512 vm_map_entry_release(count); 513 } 514 515 /* 516 * kmem_init: 517 * 518 * Create the kernel map; insert a mapping covering kernel text, 519 * data, bss, and all space allocated thus far (`boostrap' data). The 520 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 521 * `start' as allocated, and the range between `start' and `end' as free. 522 * 523 * Depend on the zalloc bootstrap cache to get our vm_map_entry_t. 524 */ 525 void 526 kmem_init(vm_offset_t start, vm_offset_t end) 527 { 528 vm_map_t m; 529 int count; 530 531 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 532 vm_map_lock(m); 533 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 534 kernel_map = m; 535 kernel_map->system_map = 1; 536 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 537 vm_map_insert(m, &count, NULL, (vm_offset_t) 0, 538 VM_MIN_KERNEL_ADDRESS, start, 539 VM_MAPTYPE_NORMAL, 540 VM_PROT_ALL, VM_PROT_ALL, 541 0); 542 /* ... and ending with the completion of the above `insert' */ 543 vm_map_unlock(m); 544 vm_map_entry_release(count); 545 } 546