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 1.29 2007/06/07 23:14:29 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 #include <sys/kernel.h> 77 #include <sys/sysctl.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <sys/lock.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_kern.h> 88 #include <vm/vm_extern.h> 89 90 struct vm_map kernel_map; 91 struct vm_map clean_map; 92 struct vm_map buffer_map; 93 94 /* 95 * kmem_alloc_pageable: 96 * 97 * Allocate pageable memory to the kernel's address map. 98 * "map" must be kernel_map or a submap of kernel_map. 99 */ 100 vm_offset_t 101 kmem_alloc_pageable(vm_map_t map, vm_size_t size) 102 { 103 vm_offset_t addr; 104 int result; 105 106 size = round_page(size); 107 addr = vm_map_min(map); 108 result = vm_map_find(map, NULL, (vm_offset_t) 0, 109 &addr, size, PAGE_SIZE, 110 TRUE, 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, vm_size_t align) 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, align, 134 TRUE, VM_MAPTYPE_NORMAL, 135 VM_PROT_ALL, VM_PROT_ALL, 136 MAP_NOFAULT); 137 if (result != KERN_SUCCESS) { 138 return (0); 139 } 140 return (addr); 141 } 142 143 /* 144 * Allocate wired-down memory in the kernel's address map 145 * or a submap. 146 */ 147 vm_offset_t 148 kmem_alloc3(vm_map_t map, vm_size_t size, int kmflags) 149 { 150 vm_offset_t addr; 151 vm_offset_t i; 152 int count; 153 154 size = round_page(size); 155 156 if (kmflags & KM_KRESERVE) 157 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); 158 else 159 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 160 161 /* 162 * Use the kernel object for wired-down kernel pages. Assume that no 163 * region of the kernel object is referenced more than once. 164 * 165 * Locate sufficient space in the map. This will give us the final 166 * virtual address for the new memory, and thus will tell us the 167 * offset within the kernel map. 168 */ 169 vm_map_lock(map); 170 if (vm_map_findspace(map, vm_map_min(map), size, PAGE_SIZE, 0, &addr)) { 171 vm_map_unlock(map); 172 if (kmflags & KM_KRESERVE) 173 vm_map_entry_krelease(count); 174 else 175 vm_map_entry_release(count); 176 return (0); 177 } 178 vm_object_reference(&kernel_object); 179 vm_map_insert(map, &count, 180 &kernel_object, addr, addr, addr + size, 181 VM_MAPTYPE_NORMAL, 182 VM_PROT_ALL, VM_PROT_ALL, 183 0); 184 vm_map_unlock(map); 185 if (kmflags & KM_KRESERVE) 186 vm_map_entry_krelease(count); 187 else 188 vm_map_entry_release(count); 189 190 /* 191 * Guarantee that there are pages already in this object before 192 * calling vm_map_wire. This is to prevent the following 193 * scenario: 194 * 195 * 1) Threads have swapped out, so that there is a pager for the 196 * kernel_object. 2) The kmsg zone is empty, and so we are 197 * kmem_allocing a new page for it. 3) vm_map_wire calls vm_fault; 198 * there is no page, but there is a pager, so we call 199 * pager_data_request. But the kmsg zone is empty, so we must 200 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when 201 * we get the data back from the pager, it will be (very stale) 202 * non-zero data. kmem_alloc is defined to return zero-filled memory. 203 * 204 * We're intentionally not activating the pages we allocate to prevent a 205 * race with page-out. vm_map_wire will wire the pages. 206 */ 207 208 for (i = 0; i < size; i += PAGE_SIZE) { 209 vm_page_t mem; 210 211 mem = vm_page_grab(&kernel_object, OFF_TO_IDX(addr + i), 212 VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 213 if ((mem->flags & PG_ZERO) == 0) 214 vm_page_zero_fill(mem); 215 mem->valid = VM_PAGE_BITS_ALL; 216 vm_page_flag_clear(mem, PG_ZERO); 217 vm_page_wakeup(mem); 218 } 219 220 /* 221 * And finally, mark the data as non-pageable. 222 */ 223 224 vm_map_wire(map, (vm_offset_t) addr, addr + size, kmflags); 225 226 return (addr); 227 } 228 229 /* 230 * kmem_free: 231 * 232 * Release a region of kernel virtual memory allocated 233 * with kmem_alloc, and return the physical pages 234 * associated with that region. 235 * 236 * WARNING! If the caller entered pages into the region using 237 * pmap_kenter() it must remove the pages using pmap_kremove[_quick]() 238 * before freeing the underlying kmem, otherwise resident_count will 239 * be mistabulated. 240 * 241 * This routine may not block on kernel maps. 242 */ 243 void 244 kmem_free(vm_map_t map, vm_offset_t addr, vm_size_t size) 245 { 246 vm_map_remove(map, trunc_page(addr), round_page(addr + size)); 247 } 248 249 /* 250 * kmem_suballoc: 251 * 252 * Used to break a system map into smaller maps, usually to reduce 253 * contention and to provide large KVA spaces for subsystems like the 254 * buffer cache. 255 * 256 * parent Map to take range from 257 * result 258 * size Size of range to find 259 * min, max Returned endpoints of map 260 * pageable Can the region be paged 261 */ 262 void 263 kmem_suballoc(vm_map_t parent, vm_map_t result, 264 vm_offset_t *min, vm_offset_t *max, vm_size_t size) 265 { 266 int ret; 267 268 size = round_page(size); 269 270 *min = (vm_offset_t) vm_map_min(parent); 271 ret = vm_map_find(parent, NULL, (vm_offset_t) 0, 272 min, size, PAGE_SIZE, 273 TRUE, VM_MAPTYPE_UNSPECIFIED, 274 VM_PROT_ALL, VM_PROT_ALL, 275 0); 276 if (ret != KERN_SUCCESS) { 277 kprintf("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 vm_map_init(result, *min, *max, vm_map_pmap(parent)); 283 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS) 284 panic("kmem_suballoc: unable to change range to submap"); 285 } 286 287 /* 288 * kmem_alloc_wait: 289 * 290 * Allocates pageable memory from a sub-map of the kernel. If the submap 291 * has no room, the caller sleeps waiting for more memory in the submap. 292 * 293 * This routine may block. 294 */ 295 296 vm_offset_t 297 kmem_alloc_wait(vm_map_t map, vm_size_t size) 298 { 299 vm_offset_t addr; 300 int count; 301 302 size = round_page(size); 303 304 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 305 306 for (;;) { 307 /* 308 * To make this work for more than one map, use the map's lock 309 * to lock out sleepers/wakers. 310 */ 311 vm_map_lock(map); 312 if (vm_map_findspace(map, vm_map_min(map), 313 size, PAGE_SIZE, 0, &addr) == 0) { 314 break; 315 } 316 /* no space now; see if we can ever get space */ 317 if (vm_map_max(map) - vm_map_min(map) < size) { 318 vm_map_entry_release(count); 319 vm_map_unlock(map); 320 return (0); 321 } 322 vm_map_unlock(map); 323 tsleep(map, 0, "kmaw", 0); 324 } 325 vm_map_insert(map, &count, 326 NULL, (vm_offset_t) 0, 327 addr, addr + size, 328 VM_MAPTYPE_NORMAL, 329 VM_PROT_ALL, VM_PROT_ALL, 330 0); 331 vm_map_unlock(map); 332 vm_map_entry_release(count); 333 return (addr); 334 } 335 336 /* 337 * kmem_free_wakeup: 338 * 339 * Returns memory to a submap of the kernel, and wakes up any processes 340 * waiting for memory in that map. 341 */ 342 void 343 kmem_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 344 { 345 int count; 346 347 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 348 vm_map_lock(map); 349 vm_map_delete(map, trunc_page(addr), round_page(addr + size), &count); 350 wakeup(map); 351 vm_map_unlock(map); 352 vm_map_entry_release(count); 353 } 354 355 /* 356 * kmem_init: 357 * 358 * Create the kernel_map and insert mappings to cover areas already 359 * allocated or reserved thus far. That is, the area (KvaStart,start) 360 * and (end,KvaEnd) must be marked as allocated. 361 * 362 * virtual2_start/end is a cutout Between KvaStart and start, 363 * for x86_64 due to the location of KERNBASE (at -2G). 364 * 365 * We could use a min_offset of 0 instead of KvaStart, but since the 366 * min_offset is not used for any calculations other then a bounds check 367 * it does not effect readability. KvaStart is more appropriate. 368 * 369 * Depend on the zalloc bootstrap cache to get our vm_map_entry_t. 370 */ 371 void 372 kmem_init(vm_offset_t start, vm_offset_t end) 373 { 374 vm_offset_t addr; 375 vm_map_t m; 376 int count; 377 378 m = vm_map_create(&kernel_map, &kernel_pmap, KvaStart, KvaEnd); 379 vm_map_lock(m); 380 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 381 m->system_map = 1; 382 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 383 addr = KvaStart; 384 if (virtual2_start) { 385 if (addr < virtual2_start) { 386 vm_map_insert(m, &count, NULL, (vm_offset_t) 0, 387 addr, virtual2_start, 388 VM_MAPTYPE_NORMAL, 389 VM_PROT_ALL, VM_PROT_ALL, 390 0); 391 } 392 addr = virtual2_end; 393 } 394 if (addr < start) { 395 vm_map_insert(m, &count, NULL, (vm_offset_t) 0, 396 addr, start, 397 VM_MAPTYPE_NORMAL, 398 VM_PROT_ALL, VM_PROT_ALL, 399 0); 400 } 401 addr = end; 402 if (addr < KvaEnd) { 403 vm_map_insert(m, &count, NULL, (vm_offset_t) 0, 404 addr, KvaEnd, 405 VM_MAPTYPE_NORMAL, 406 VM_PROT_ALL, VM_PROT_ALL, 407 0); 408 } 409 /* ... and ending with the completion of the above `insert' */ 410 vm_map_unlock(m); 411 vm_map_entry_release(count); 412 } 413 414 static int 415 kvm_size(SYSCTL_HANDLER_ARGS) 416 { 417 unsigned long ksize = KvaSize; 418 419 return sysctl_handle_long(oidp, &ksize, 0, req); 420 } 421 SYSCTL_PROC(_vm, OID_AUTO, kvm_size, CTLTYPE_LONG|CTLFLAG_RD, 422 0, 0, kvm_size, "IU", "Size of KVM"); 423 424 static int 425 kvm_free(SYSCTL_HANDLER_ARGS) 426 { 427 unsigned long kfree = virtual_end - kernel_vm_end; 428 429 return sysctl_handle_long(oidp, &kfree, 0, req); 430 } 431 SYSCTL_PROC(_vm, OID_AUTO, kvm_free, CTLTYPE_LONG|CTLFLAG_RD, 432 0, 0, kvm_free, "IU", "Amount of KVM free"); 433 434