2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
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18 * This product includes software developed by the University of
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24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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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
36 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
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.
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.
54 * Carnegie Mellon requests users of this software to return to
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
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 1.21 2005/04/02 15:58:16 joerg Exp $
69 * Kernel memory management.
72 #include <sys/param.h>
73 #include <sys/systm.h>
75 #include <sys/malloc.h>
78 #include <vm/vm_param.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>
88 vm_map_t kernel_map=0;
91 vm_map_t buffer_map=0;
94 * kmem_alloc_pageable:
96 * Allocate pageable memory to the kernel's address map.
97 * "map" must be kernel_map or a submap of kernel_map.
100 kmem_alloc_pageable(vm_map_t map, vm_size_t size)
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, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
109 if (result != KERN_SUCCESS) {
116 * kmem_alloc_nofault:
118 * Same as kmem_alloc_pageable, except that it create a nofault entry.
121 kmem_alloc_nofault(vm_map_t map, vm_size_t size)
126 size = round_page(size);
127 addr = vm_map_min(map);
128 result = vm_map_find(map, NULL, (vm_offset_t) 0,
129 &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
130 if (result != KERN_SUCCESS) {
137 * Allocate wired-down memory in the kernel's address map
141 kmem_alloc3(vm_map_t map, vm_size_t size, int kmflags)
148 size = round_page(size);
150 if (kmflags & KM_KRESERVE)
151 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT);
153 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
156 * Use the kernel object for wired-down kernel pages. Assume that no
157 * region of the kernel object is referenced more than once.
159 * Locate sufficient space in the map. This will give us the final
160 * virtual address for the new memory, and thus will tell us the
161 * offset within the kernel map.
164 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) {
166 if (kmflags & KM_KRESERVE)
167 vm_map_entry_krelease(count);
169 vm_map_entry_release(count);
172 offset = addr - VM_MIN_KERNEL_ADDRESS;
173 vm_object_reference(kernel_object);
174 vm_map_insert(map, &count,
175 kernel_object, offset, addr, addr + size,
176 VM_PROT_ALL, VM_PROT_ALL, 0);
178 if (kmflags & KM_KRESERVE)
179 vm_map_entry_krelease(count);
181 vm_map_entry_release(count);
184 * Guarantee that there are pages already in this object before
185 * calling vm_map_wire. This is to prevent the following
188 * 1) Threads have swapped out, so that there is a pager for the
189 * kernel_object. 2) The kmsg zone is empty, and so we are
190 * kmem_allocing a new page for it. 3) vm_map_wire calls vm_fault;
191 * there is no page, but there is a pager, so we call
192 * pager_data_request. But the kmsg zone is empty, so we must
193 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
194 * we get the data back from the pager, it will be (very stale)
195 * non-zero data. kmem_alloc is defined to return zero-filled memory.
197 * We're intentionally not activating the pages we allocate to prevent a
198 * race with page-out. vm_map_wire will wire the pages.
201 for (i = 0; i < size; i += PAGE_SIZE) {
204 mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i),
205 VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
206 if ((mem->flags & PG_ZERO) == 0)
207 vm_page_zero_fill(mem);
208 mem->valid = VM_PAGE_BITS_ALL;
209 vm_page_flag_clear(mem, PG_ZERO);
214 * And finally, mark the data as non-pageable.
217 (void) vm_map_wire(map, (vm_offset_t) addr, addr + size, kmflags);
225 * Release a region of kernel virtual memory allocated
226 * with kmem_alloc, and return the physical pages
227 * associated with that region.
229 * This routine may not block on kernel maps.
232 kmem_free(vm_map_t map, vm_offset_t addr, vm_size_t size)
234 (void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
240 * Allocates a map to manage a subrange
241 * of the kernel virtual address space.
243 * Arguments are as follows:
245 * parent Map to take range from
246 * size Size of range to find
247 * min, max Returned endpoints of map
248 * pageable Can the region be paged
251 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max,
257 size = round_page(size);
259 *min = (vm_offset_t) vm_map_min(parent);
260 ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
261 min, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
262 if (ret != KERN_SUCCESS) {
263 printf("kmem_suballoc: bad status return of %d.\n", ret);
264 panic("kmem_suballoc");
267 pmap_reference(vm_map_pmap(parent));
268 result = vm_map_create(vm_map_pmap(parent), *min, *max);
270 panic("kmem_suballoc: cannot create submap");
271 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
272 panic("kmem_suballoc: unable to change range to submap");
279 * Allocate wired-down memory in the kernel's address map for the higher
280 * level kernel memory allocator (kern/kern_malloc.c). We cannot use
281 * kmem_alloc() because we may need to allocate memory at interrupt
282 * level where we cannot block (canwait == FALSE).
284 * We don't worry about expanding the map (adding entries) since entries
285 * for wired maps are statically allocated.
287 * NOTE: Please see kmem_slab_alloc() for a better explanation of the
291 kmem_malloc(vm_map_t map, vm_size_t size, int flags)
293 vm_offset_t offset, i;
294 vm_map_entry_t entry;
297 int count, vmflags, wanted_reserve;
300 if (map != kernel_map)
301 panic("kmem_malloc: map != kernel_map");
303 size = round_page(size);
304 addr = vm_map_min(map);
307 * Locate sufficient space in the map. This will give us the final
308 * virtual address for the new memory, and thus will tell us the
309 * offset within the kernel map. If we are unable to allocate space
310 * and neither RNOWAIT or NULLOK is set, we panic.
312 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
314 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) {
316 vm_map_entry_release(count);
317 if ((flags & M_NULLOK) == 0) {
318 panic("kmem_malloc(%ld): kernel_map too small: "
319 "%ld total allocated",
320 (long)size, (long)map->size);
324 offset = addr - VM_MIN_KERNEL_ADDRESS;
325 vm_object_reference(kmem_object);
326 vm_map_insert(map, &count,
327 kmem_object, offset, addr, addr + size,
328 VM_PROT_ALL, VM_PROT_ALL, 0);
333 vmflags = VM_ALLOC_SYSTEM; /* XXX M_USE_RESERVE? */
334 if ((flags & (M_WAITOK|M_RNOWAIT)) == 0)
335 panic("kmem_malloc: bad flags %08x (%p)\n", flags, ((int **)&map)[-1]);
336 if (flags & M_USE_INTERRUPT_RESERVE)
337 vmflags |= VM_ALLOC_INTERRUPT;
339 for (i = 0; i < size; i += PAGE_SIZE) {
341 * Only allocate PQ_CACHE pages for M_WAITOK requests and
342 * then only if we are not preempting.
344 if (flags & M_WAITOK) {
345 if (td->td_preempted) {
346 vmflags &= ~VM_ALLOC_NORMAL;
349 vmflags |= VM_ALLOC_NORMAL;
354 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i), vmflags);
357 * Ran out of space, free everything up and return. Don't need
358 * to lock page queues here as we know that the pages we got
359 * aren't on any queues.
361 * If M_WAITOK is set we can yield or block.
364 if (flags & M_WAITOK) {
365 if (wanted_reserve) {
374 i -= PAGE_SIZE; /* retry */
378 * Free the pages before removing the map entry.
379 * They are already marked busy. Calling
380 * vm_map_delete before the pages has been freed or
381 * unbusied will cause a deadlock.
385 m = vm_page_lookup(kmem_object,
386 OFF_TO_IDX(offset + i));
389 vm_map_delete(map, addr, addr + size, &count);
391 vm_map_entry_release(count);
394 vm_page_flag_clear(m, PG_ZERO);
395 m->valid = VM_PAGE_BITS_ALL;
399 * Mark map entry as non-pageable. Assert: vm_map_insert() will never
400 * be able to extend the previous entry so there will be a new entry
401 * exactly corresponding to this address range and it will have
404 if (!vm_map_lookup_entry(map, addr, &entry) ||
405 entry->start != addr || entry->end != addr + size ||
406 entry->wired_count != 0)
407 panic("kmem_malloc: entry not found or misaligned");
408 entry->wired_count = 1;
410 vm_map_simplify_entry(map, entry, &count);
413 * Loop thru pages, entering them in the pmap. (We cannot add them to
414 * the wired count without wrapping the vm_page_queue_lock in
417 for (i = 0; i < size; i += PAGE_SIZE) {
418 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
422 * Because this is kernel_pmap, this call will not block.
424 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1);
425 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
428 vm_map_entry_release(count);
436 * Allocates pageable memory from a sub-map of the kernel. If the submap
437 * has no room, the caller sleeps waiting for more memory in the submap.
439 * This routine may block.
443 kmem_alloc_wait(vm_map_t map, vm_size_t size)
448 size = round_page(size);
450 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
454 * To make this work for more than one map, use the map's lock
455 * to lock out sleepers/wakers.
458 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr) == 0)
460 /* no space now; see if we can ever get space */
461 if (vm_map_max(map) - vm_map_min(map) < size) {
462 vm_map_entry_release(count);
467 tsleep(map, 0, "kmaw", 0);
469 vm_map_insert(map, &count,
470 NULL, (vm_offset_t) 0,
471 addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
473 vm_map_entry_release(count);
480 * Returns memory to a submap of the kernel, and wakes up any processes
481 * waiting for memory in that map.
484 kmem_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size)
488 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
490 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size), &count);
493 vm_map_entry_release(count);
499 * Create the kernel map; insert a mapping covering kernel text,
500 * data, bss, and all space allocated thus far (`boostrap' data). The
501 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and
502 * `start' as allocated, and the range between `start' and `end' as free.
504 * Depend on the zalloc bootstrap cache to get our vm_map_entry_t.
507 kmem_init(vm_offset_t start, vm_offset_t end)
512 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
514 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
516 kernel_map->system_map = 1;
517 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
518 (void) vm_map_insert(m, &count, NULL, (vm_offset_t) 0,
519 VM_MIN_KERNEL_ADDRESS, start, VM_PROT_ALL, VM_PROT_ALL, 0);
520 /* ... and ending with the completion of the above `insert' */
522 vm_map_entry_release(count);