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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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 * $Id: vm_kern.c,v 1.56 1999/07/01 19:53:40 peter Exp $
68 * Kernel memory management.
71 #include <sys/param.h>
72 #include <sys/systm.h>
74 #include <sys/malloc.h>
77 #include <vm/vm_param.h>
78 #include <vm/vm_prot.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_extern.h>
87 vm_map_t kernel_map=0;
91 vm_map_t buffer_map=0;
98 * kmem_alloc_pageable:
100 * Allocate pageable memory to the kernel's address map.
101 * "map" must be kernel_map or a submap of kernel_map.
105 kmem_alloc_pageable(map, size)
107 register vm_size_t size;
112 size = round_page(size);
113 addr = vm_map_min(map);
114 result = vm_map_find(map, NULL, (vm_offset_t) 0,
115 &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
116 if (result != KERN_SUCCESS) {
123 * kmem_alloc_nofault:
125 * Same as kmem_alloc_pageable, except that it create a nofault entry.
129 kmem_alloc_nofault(map, size)
131 register vm_size_t size;
136 size = round_page(size);
137 addr = vm_map_min(map);
138 result = vm_map_find(map, NULL, (vm_offset_t) 0,
139 &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
140 if (result != KERN_SUCCESS) {
147 * Allocate wired-down memory in the kernel's address map
151 kmem_alloc(map, size)
152 register vm_map_t map;
153 register vm_size_t size;
156 register vm_offset_t offset;
159 size = round_page(size);
162 * Use the kernel object for wired-down kernel pages. Assume that no
163 * region of the kernel object is referenced more than once.
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.
172 if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
176 offset = addr - VM_MIN_KERNEL_ADDRESS;
177 vm_object_reference(kernel_object);
178 vm_map_insert(map, kernel_object, offset, addr, addr + size,
179 VM_PROT_ALL, VM_PROT_ALL, 0);
183 * Guarantee that there are pages already in this object before
184 * calling vm_map_pageable. This is to prevent the following
187 * 1) Threads have swapped out, so that there is a pager for the
188 * kernel_object. 2) The kmsg zone is empty, and so we are
189 * kmem_allocing a new page for it. 3) vm_map_pageable calls vm_fault;
190 * there is no page, but there is a pager, so we call
191 * pager_data_request. But the kmsg zone is empty, so we must
192 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
193 * we get the data back from the pager, it will be (very stale)
194 * non-zero data. kmem_alloc is defined to return zero-filled memory.
196 * We're intentionally not activating the pages we allocate to prevent a
197 * race with page-out. vm_map_pageable will wire the pages.
200 for (i = 0; i < size; i += PAGE_SIZE) {
203 mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i),
204 VM_ALLOC_ZERO | VM_ALLOC_RETRY);
205 if ((mem->flags & PG_ZERO) == 0)
206 vm_page_zero_fill(mem);
207 mem->valid = VM_PAGE_BITS_ALL;
208 vm_page_flag_clear(mem, PG_ZERO);
213 * And finally, mark the data as non-pageable.
216 (void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
224 * Release a region of kernel virtual memory allocated
225 * with kmem_alloc, and return the physical pages
226 * associated with that region.
228 * This routine may not block on kernel maps.
231 kmem_free(map, addr, size)
233 register vm_offset_t addr;
236 (void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
242 * Allocates a map to manage a subrange
243 * of the kernel virtual address space.
245 * Arguments are as follows:
247 * parent Map to take range from
248 * size Size of range to find
249 * min, max Returned endpoints of map
250 * pageable Can the region be paged
253 kmem_suballoc(parent, min, max, size)
254 register vm_map_t parent;
255 vm_offset_t *min, *max;
256 register vm_size_t size;
261 size = round_page(size);
263 *min = (vm_offset_t) vm_map_min(parent);
264 ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
265 min, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
266 if (ret != KERN_SUCCESS) {
267 printf("kmem_suballoc: bad status return of %d.\n", ret);
268 panic("kmem_suballoc");
271 pmap_reference(vm_map_pmap(parent));
272 result = vm_map_create(vm_map_pmap(parent), *min, *max);
274 panic("kmem_suballoc: cannot create submap");
275 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
276 panic("kmem_suballoc: unable to change range to submap");
283 * Allocate wired-down memory in the kernel's address map for the higher
284 * level kernel memory allocator (kern/kern_malloc.c). We cannot use
285 * kmem_alloc() because we may need to allocate memory at interrupt
286 * level where we cannot block (canwait == FALSE).
288 * This routine has its own private kernel submap (kmem_map) and object
289 * (kmem_object). This, combined with the fact that only malloc uses
290 * this routine, ensures that we will never block in map or object waits.
292 * Note that this still only works in a uni-processor environment and
293 * when called at splhigh().
295 * We don't worry about expanding the map (adding entries) since entries
296 * for wired maps are statically allocated.
298 * NOTE: This routine is not supposed to block if M_NOWAIT is set, but
299 * I have not verified that it actually does not block.
302 kmem_malloc(map, size, flags)
303 register vm_map_t map;
304 register vm_size_t size;
307 register vm_offset_t offset, i;
308 vm_map_entry_t entry;
312 if (map != kmem_map && map != mb_map)
313 panic("kmem_malloc: map != {kmem,mb}_map");
315 size = round_page(size);
316 addr = vm_map_min(map);
319 * Locate sufficient space in the map. This will give us the final
320 * virtual address for the new memory, and thus will tell us the
321 * offset within the kernel map.
324 if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
328 printf("Out of mbuf clusters - adjust NMBCLUSTERS or increase maxusers!\n");
331 if ((flags & M_NOWAIT) == 0)
332 panic("kmem_malloc(%ld): kmem_map too small: %ld total allocated",
333 (long)size, (long)map->size);
336 offset = addr - VM_MIN_KERNEL_ADDRESS;
337 vm_object_reference(kmem_object);
338 vm_map_insert(map, kmem_object, offset, addr, addr + size,
339 VM_PROT_ALL, VM_PROT_ALL, 0);
341 for (i = 0; i < size; i += PAGE_SIZE) {
343 * Note: if M_NOWAIT specified alone, allocate from
344 * interrupt-safe queues only (just the free list). If
345 * M_ASLEEP or M_USE_RESERVE is also specified, we can also
346 * allocate from the cache. Neither of the latter two
347 * flags may be specified from an interrupt since interrupts
348 * are not allowed to mess with the cache queue.
351 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i),
352 ((flags & (M_NOWAIT|M_ASLEEP|M_USE_RESERVE)) == M_NOWAIT) ?
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.
362 if ((flags & M_NOWAIT) == 0) {
368 vm_map_delete(map, addr, addr + size);
370 if (flags & M_ASLEEP) {
375 vm_page_flag_clear(m, PG_ZERO);
376 m->valid = VM_PAGE_BITS_ALL;
380 * Mark map entry as non-pageable. Assert: vm_map_insert() will never
381 * be able to extend the previous entry so there will be a new entry
382 * exactly corresponding to this address range and it will have
385 if (!vm_map_lookup_entry(map, addr, &entry) ||
386 entry->start != addr || entry->end != addr + size ||
387 entry->wired_count != 0)
388 panic("kmem_malloc: entry not found or misaligned");
389 entry->wired_count = 1;
391 vm_map_simplify_entry(map, entry);
394 * Loop thru pages, entering them in the pmap. (We cannot add them to
395 * the wired count without wrapping the vm_page_queue_lock in
398 for (i = 0; i < size; i += PAGE_SIZE) {
399 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
403 * Because this is kernel_pmap, this call will not block.
405 pmap_enter(kernel_pmap, addr + i, VM_PAGE_TO_PHYS(m),
407 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
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.
420 * This routine may block.
424 kmem_alloc_wait(map, size)
430 size = round_page(size);
434 * To make this work for more than one map, use the map's lock
435 * to lock out sleepers/wakers.
438 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0)
440 /* no space now; see if we can ever get space */
441 if (vm_map_max(map) - vm_map_min(map) < size) {
446 tsleep(map, PVM, "kmaw", 0);
448 vm_map_insert(map, NULL, (vm_offset_t) 0, addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
456 * Returns memory to a submap of the kernel, and wakes up any processes
457 * waiting for memory in that map.
460 kmem_free_wakeup(map, addr, size)
466 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
474 * Create the kernel map; insert a mapping covering kernel text,
475 * data, bss, and all space allocated thus far (`boostrap' data). The
476 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and
477 * `start' as allocated, and the range between `start' and `end' as free.
481 kmem_init(start, end)
482 vm_offset_t start, end;
486 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
488 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
490 kernel_map->system_map = 1;
491 (void) vm_map_insert(m, NULL, (vm_offset_t) 0,
492 VM_MIN_KERNEL_ADDRESS, start, VM_PROT_ALL, VM_PROT_ALL, 0);
493 /* ... and ending with the completion of the above `insert' */