2 * linux/kernel/power/snapshot.c
4 * This file provides system snapshot/restore functionality for swsusp.
6 * Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
7 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
9 * This file is released under the GPLv2.
13 #include <linux/version.h>
14 #include <linux/module.h>
16 #include <linux/suspend.h>
17 #include <linux/delay.h>
18 #include <linux/bitops.h>
19 #include <linux/spinlock.h>
20 #include <linux/kernel.h>
22 #include <linux/device.h>
23 #include <linux/init.h>
24 #include <linux/bootmem.h>
25 #include <linux/syscalls.h>
26 #include <linux/console.h>
27 #include <linux/highmem.h>
28 #include <linux/list.h>
30 #include <asm/uaccess.h>
31 #include <asm/mmu_context.h>
32 #include <asm/pgtable.h>
33 #include <asm/tlbflush.h>
38 static int swsusp_page_is_free(struct page *);
39 static void swsusp_set_page_forbidden(struct page *);
40 static void swsusp_unset_page_forbidden(struct page *);
43 * Preferred image size in bytes (tunable via /sys/power/image_size).
44 * When it is set to N, swsusp will do its best to ensure the image
45 * size will not exceed N bytes, but if that is impossible, it will
46 * try to create the smallest image possible.
48 unsigned long image_size = 500 * 1024 * 1024;
50 /* List of PBEs needed for restoring the pages that were allocated before
51 * the suspend and included in the suspend image, but have also been
52 * allocated by the "resume" kernel, so their contents cannot be written
53 * directly to their "original" page frames.
55 struct pbe *restore_pblist;
57 /* Pointer to an auxiliary buffer (1 page) */
61 * @safe_needed - on resume, for storing the PBE list and the image,
62 * we can only use memory pages that do not conflict with the pages
63 * used before suspend. The unsafe pages have PageNosaveFree set
64 * and we count them using unsafe_pages.
66 * Each allocated image page is marked as PageNosave and PageNosaveFree
67 * so that swsusp_free() can release it.
72 #define PG_UNSAFE_CLEAR 1
73 #define PG_UNSAFE_KEEP 0
75 static unsigned int allocated_unsafe_pages;
77 static void *get_image_page(gfp_t gfp_mask, int safe_needed)
81 res = (void *)get_zeroed_page(gfp_mask);
83 while (res && swsusp_page_is_free(virt_to_page(res))) {
84 /* The page is unsafe, mark it for swsusp_free() */
85 swsusp_set_page_forbidden(virt_to_page(res));
86 allocated_unsafe_pages++;
87 res = (void *)get_zeroed_page(gfp_mask);
90 swsusp_set_page_forbidden(virt_to_page(res));
91 swsusp_set_page_free(virt_to_page(res));
96 unsigned long get_safe_page(gfp_t gfp_mask)
98 return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
101 static struct page *alloc_image_page(gfp_t gfp_mask)
105 page = alloc_page(gfp_mask);
107 swsusp_set_page_forbidden(page);
108 swsusp_set_page_free(page);
114 * free_image_page - free page represented by @addr, allocated with
115 * get_image_page (page flags set by it must be cleared)
118 static inline void free_image_page(void *addr, int clear_nosave_free)
122 BUG_ON(!virt_addr_valid(addr));
124 page = virt_to_page(addr);
126 swsusp_unset_page_forbidden(page);
127 if (clear_nosave_free)
128 swsusp_unset_page_free(page);
133 /* struct linked_page is used to build chains of pages */
135 #define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *))
138 struct linked_page *next;
139 char data[LINKED_PAGE_DATA_SIZE];
140 } __attribute__((packed));
143 free_list_of_pages(struct linked_page *list, int clear_page_nosave)
146 struct linked_page *lp = list->next;
148 free_image_page(list, clear_page_nosave);
154 * struct chain_allocator is used for allocating small objects out of
155 * a linked list of pages called 'the chain'.
157 * The chain grows each time when there is no room for a new object in
158 * the current page. The allocated objects cannot be freed individually.
159 * It is only possible to free them all at once, by freeing the entire
162 * NOTE: The chain allocator may be inefficient if the allocated objects
163 * are not much smaller than PAGE_SIZE.
166 struct chain_allocator {
167 struct linked_page *chain; /* the chain */
168 unsigned int used_space; /* total size of objects allocated out
169 * of the current page
171 gfp_t gfp_mask; /* mask for allocating pages */
172 int safe_needed; /* if set, only "safe" pages are allocated */
176 chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed)
179 ca->used_space = LINKED_PAGE_DATA_SIZE;
180 ca->gfp_mask = gfp_mask;
181 ca->safe_needed = safe_needed;
184 static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
188 if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
189 struct linked_page *lp;
191 lp = get_image_page(ca->gfp_mask, ca->safe_needed);
195 lp->next = ca->chain;
199 ret = ca->chain->data + ca->used_space;
200 ca->used_space += size;
205 * Data types related to memory bitmaps.
207 * Memory bitmap is a structure consiting of many linked lists of
208 * objects. The main list's elements are of type struct zone_bitmap
209 * and each of them corresonds to one zone. For each zone bitmap
210 * object there is a list of objects of type struct bm_block that
211 * represent each blocks of bitmap in which information is stored.
213 * struct memory_bitmap contains a pointer to the main list of zone
214 * bitmap objects, a struct bm_position used for browsing the bitmap,
215 * and a pointer to the list of pages used for allocating all of the
216 * zone bitmap objects and bitmap block objects.
218 * NOTE: It has to be possible to lay out the bitmap in memory
219 * using only allocations of order 0. Additionally, the bitmap is
220 * designed to work with arbitrary number of zones (this is over the
221 * top for now, but let's avoid making unnecessary assumptions ;-).
223 * struct zone_bitmap contains a pointer to a list of bitmap block
224 * objects and a pointer to the bitmap block object that has been
225 * most recently used for setting bits. Additionally, it contains the
226 * pfns that correspond to the start and end of the represented zone.
228 * struct bm_block contains a pointer to the memory page in which
229 * information is stored (in the form of a block of bitmap)
230 * It also contains the pfns that correspond to the start and end of
231 * the represented memory area.
234 #define BM_END_OF_MAP (~0UL)
236 #define BM_BITS_PER_BLOCK (PAGE_SIZE << 3)
239 struct list_head hook; /* hook into a list of bitmap blocks */
240 unsigned long start_pfn; /* pfn represented by the first bit */
241 unsigned long end_pfn; /* pfn represented by the last bit plus 1 */
242 unsigned long *data; /* bitmap representing pages */
245 static inline unsigned long bm_block_bits(struct bm_block *bb)
247 return bb->end_pfn - bb->start_pfn;
250 /* strcut bm_position is used for browsing memory bitmaps */
253 struct bm_block *block;
257 struct memory_bitmap {
258 struct list_head blocks; /* list of bitmap blocks */
259 struct linked_page *p_list; /* list of pages used to store zone
260 * bitmap objects and bitmap block
263 struct bm_position cur; /* most recently used bit position */
266 /* Functions that operate on memory bitmaps */
268 static void memory_bm_position_reset(struct memory_bitmap *bm)
270 bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);
274 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
277 * create_bm_block_list - create a list of block bitmap objects
278 * @nr_blocks - number of blocks to allocate
279 * @list - list to put the allocated blocks into
280 * @ca - chain allocator to be used for allocating memory
282 static int create_bm_block_list(unsigned long pages,
283 struct list_head *list,
284 struct chain_allocator *ca)
286 unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
288 while (nr_blocks-- > 0) {
291 bb = chain_alloc(ca, sizeof(struct bm_block));
294 list_add(&bb->hook, list);
301 struct list_head hook;
307 * free_mem_extents - free a list of memory extents
308 * @list - list of extents to empty
310 static void free_mem_extents(struct list_head *list)
312 struct mem_extent *ext, *aux;
314 list_for_each_entry_safe(ext, aux, list, hook) {
315 list_del(&ext->hook);
321 * create_mem_extents - create a list of memory extents representing
322 * contiguous ranges of PFNs
323 * @list - list to put the extents into
324 * @gfp_mask - mask to use for memory allocations
326 static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
330 INIT_LIST_HEAD(list);
332 for_each_populated_zone(zone) {
333 unsigned long zone_start, zone_end;
334 struct mem_extent *ext, *cur, *aux;
336 zone_start = zone->zone_start_pfn;
337 zone_end = zone->zone_start_pfn + zone->spanned_pages;
339 list_for_each_entry(ext, list, hook)
340 if (zone_start <= ext->end)
343 if (&ext->hook == list || zone_end < ext->start) {
344 /* New extent is necessary */
345 struct mem_extent *new_ext;
347 new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
349 free_mem_extents(list);
352 new_ext->start = zone_start;
353 new_ext->end = zone_end;
354 list_add_tail(&new_ext->hook, &ext->hook);
358 /* Merge this zone's range of PFNs with the existing one */
359 if (zone_start < ext->start)
360 ext->start = zone_start;
361 if (zone_end > ext->end)
364 /* More merging may be possible */
366 list_for_each_entry_safe_continue(cur, aux, list, hook) {
367 if (zone_end < cur->start)
369 if (zone_end < cur->end)
371 list_del(&cur->hook);
380 * memory_bm_create - allocate memory for a memory bitmap
383 memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
385 struct chain_allocator ca;
386 struct list_head mem_extents;
387 struct mem_extent *ext;
390 chain_init(&ca, gfp_mask, safe_needed);
391 INIT_LIST_HEAD(&bm->blocks);
393 error = create_mem_extents(&mem_extents, gfp_mask);
397 list_for_each_entry(ext, &mem_extents, hook) {
399 unsigned long pfn = ext->start;
400 unsigned long pages = ext->end - ext->start;
402 bb = list_entry(bm->blocks.prev, struct bm_block, hook);
404 error = create_bm_block_list(pages, bm->blocks.prev, &ca);
408 list_for_each_entry_continue(bb, &bm->blocks, hook) {
409 bb->data = get_image_page(gfp_mask, safe_needed);
416 if (pages >= BM_BITS_PER_BLOCK) {
417 pfn += BM_BITS_PER_BLOCK;
418 pages -= BM_BITS_PER_BLOCK;
420 /* This is executed only once in the loop */
427 bm->p_list = ca.chain;
428 memory_bm_position_reset(bm);
430 free_mem_extents(&mem_extents);
434 bm->p_list = ca.chain;
435 memory_bm_free(bm, PG_UNSAFE_CLEAR);
440 * memory_bm_free - free memory occupied by the memory bitmap @bm
442 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
446 list_for_each_entry(bb, &bm->blocks, hook)
448 free_image_page(bb->data, clear_nosave_free);
450 free_list_of_pages(bm->p_list, clear_nosave_free);
452 INIT_LIST_HEAD(&bm->blocks);
456 * memory_bm_find_bit - find the bit in the bitmap @bm that corresponds
457 * to given pfn. The cur_zone_bm member of @bm and the cur_block member
458 * of @bm->cur_zone_bm are updated.
460 static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
461 void **addr, unsigned int *bit_nr)
466 * Check if the pfn corresponds to the current bitmap block and find
467 * the block where it fits if this is not the case.
470 if (pfn < bb->start_pfn)
471 list_for_each_entry_continue_reverse(bb, &bm->blocks, hook)
472 if (pfn >= bb->start_pfn)
475 if (pfn >= bb->end_pfn)
476 list_for_each_entry_continue(bb, &bm->blocks, hook)
477 if (pfn >= bb->start_pfn && pfn < bb->end_pfn)
480 if (&bb->hook == &bm->blocks)
483 /* The block has been found */
485 pfn -= bb->start_pfn;
486 bm->cur.bit = pfn + 1;
492 static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
498 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
503 static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
509 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
515 static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
521 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
523 clear_bit(bit, addr);
526 static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
532 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
534 return test_bit(bit, addr);
537 static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
542 return !memory_bm_find_bit(bm, pfn, &addr, &bit);
546 * memory_bm_next_pfn - find the pfn that corresponds to the next set bit
547 * in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is
550 * It is required to run memory_bm_position_reset() before the first call to
554 static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
562 bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
563 if (bit < bm_block_bits(bb))
566 bb = list_entry(bb->hook.next, struct bm_block, hook);
569 } while (&bb->hook != &bm->blocks);
571 memory_bm_position_reset(bm);
572 return BM_END_OF_MAP;
575 bm->cur.bit = bit + 1;
576 return bb->start_pfn + bit;
580 * This structure represents a range of page frames the contents of which
581 * should not be saved during the suspend.
584 struct nosave_region {
585 struct list_head list;
586 unsigned long start_pfn;
587 unsigned long end_pfn;
590 static LIST_HEAD(nosave_regions);
593 * register_nosave_region - register a range of page frames the contents
594 * of which should not be saved during the suspend (to be used in the early
595 * initialization code)
599 __register_nosave_region(unsigned long start_pfn, unsigned long end_pfn,
602 struct nosave_region *region;
604 if (start_pfn >= end_pfn)
607 if (!list_empty(&nosave_regions)) {
608 /* Try to extend the previous region (they should be sorted) */
609 region = list_entry(nosave_regions.prev,
610 struct nosave_region, list);
611 if (region->end_pfn == start_pfn) {
612 region->end_pfn = end_pfn;
617 /* during init, this shouldn't fail */
618 region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
621 /* This allocation cannot fail */
622 region = alloc_bootmem_low(sizeof(struct nosave_region));
623 region->start_pfn = start_pfn;
624 region->end_pfn = end_pfn;
625 list_add_tail(®ion->list, &nosave_regions);
627 printk(KERN_INFO "PM: Registered nosave memory: %016lx - %016lx\n",
628 start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT);
632 * Set bits in this map correspond to the page frames the contents of which
633 * should not be saved during the suspend.
635 static struct memory_bitmap *forbidden_pages_map;
637 /* Set bits in this map correspond to free page frames. */
638 static struct memory_bitmap *free_pages_map;
641 * Each page frame allocated for creating the image is marked by setting the
642 * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
645 void swsusp_set_page_free(struct page *page)
648 memory_bm_set_bit(free_pages_map, page_to_pfn(page));
651 static int swsusp_page_is_free(struct page *page)
653 return free_pages_map ?
654 memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
657 void swsusp_unset_page_free(struct page *page)
660 memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
663 static void swsusp_set_page_forbidden(struct page *page)
665 if (forbidden_pages_map)
666 memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
669 int swsusp_page_is_forbidden(struct page *page)
671 return forbidden_pages_map ?
672 memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
675 static void swsusp_unset_page_forbidden(struct page *page)
677 if (forbidden_pages_map)
678 memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
682 * mark_nosave_pages - set bits corresponding to the page frames the
683 * contents of which should not be saved in a given bitmap.
686 static void mark_nosave_pages(struct memory_bitmap *bm)
688 struct nosave_region *region;
690 if (list_empty(&nosave_regions))
693 list_for_each_entry(region, &nosave_regions, list) {
696 pr_debug("PM: Marking nosave pages: %016lx - %016lx\n",
697 region->start_pfn << PAGE_SHIFT,
698 region->end_pfn << PAGE_SHIFT);
700 for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
701 if (pfn_valid(pfn)) {
703 * It is safe to ignore the result of
704 * mem_bm_set_bit_check() here, since we won't
705 * touch the PFNs for which the error is
708 mem_bm_set_bit_check(bm, pfn);
714 * create_basic_memory_bitmaps - create bitmaps needed for marking page
715 * frames that should not be saved and free page frames. The pointers
716 * forbidden_pages_map and free_pages_map are only modified if everything
717 * goes well, because we don't want the bits to be used before both bitmaps
721 int create_basic_memory_bitmaps(void)
723 struct memory_bitmap *bm1, *bm2;
726 BUG_ON(forbidden_pages_map || free_pages_map);
728 bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
732 error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
734 goto Free_first_object;
736 bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
738 goto Free_first_bitmap;
740 error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
742 goto Free_second_object;
744 forbidden_pages_map = bm1;
745 free_pages_map = bm2;
746 mark_nosave_pages(forbidden_pages_map);
748 pr_debug("PM: Basic memory bitmaps created\n");
755 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
762 * free_basic_memory_bitmaps - free memory bitmaps allocated by
763 * create_basic_memory_bitmaps(). The auxiliary pointers are necessary
764 * so that the bitmaps themselves are not referred to while they are being
768 void free_basic_memory_bitmaps(void)
770 struct memory_bitmap *bm1, *bm2;
772 BUG_ON(!(forbidden_pages_map && free_pages_map));
774 bm1 = forbidden_pages_map;
775 bm2 = free_pages_map;
776 forbidden_pages_map = NULL;
777 free_pages_map = NULL;
778 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
780 memory_bm_free(bm2, PG_UNSAFE_CLEAR);
783 pr_debug("PM: Basic memory bitmaps freed\n");
787 * snapshot_additional_pages - estimate the number of additional pages
788 * be needed for setting up the suspend image data structures for given
789 * zone (usually the returned value is greater than the exact number)
792 unsigned int snapshot_additional_pages(struct zone *zone)
796 res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
797 res += DIV_ROUND_UP(res * sizeof(struct bm_block), PAGE_SIZE);
801 #ifdef CONFIG_HIGHMEM
803 * count_free_highmem_pages - compute the total number of free highmem
804 * pages, system-wide.
807 static unsigned int count_free_highmem_pages(void)
810 unsigned int cnt = 0;
812 for_each_populated_zone(zone)
813 if (is_highmem(zone))
814 cnt += zone_page_state(zone, NR_FREE_PAGES);
820 * saveable_highmem_page - Determine whether a highmem page should be
821 * included in the suspend image.
823 * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
824 * and it isn't a part of a free chunk of pages.
826 static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
833 page = pfn_to_page(pfn);
834 if (page_zone(page) != zone)
837 BUG_ON(!PageHighMem(page));
839 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page) ||
847 * count_highmem_pages - compute the total number of saveable highmem
851 static unsigned int count_highmem_pages(void)
856 for_each_zone(zone) {
857 unsigned long pfn, max_zone_pfn;
859 if (!is_highmem(zone))
862 mark_free_pages(zone);
863 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
864 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
865 if (saveable_highmem_page(zone, pfn))
871 static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
875 #endif /* CONFIG_HIGHMEM */
878 * saveable_page - Determine whether a non-highmem page should be included
879 * in the suspend image.
881 * We should save the page if it isn't Nosave, and is not in the range
882 * of pages statically defined as 'unsaveable', and it isn't a part of
883 * a free chunk of pages.
885 static struct page *saveable_page(struct zone *zone, unsigned long pfn)
892 page = pfn_to_page(pfn);
893 if (page_zone(page) != zone)
896 BUG_ON(PageHighMem(page));
898 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
901 if (PageReserved(page)
902 && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
909 * count_data_pages - compute the total number of saveable non-highmem
913 static unsigned int count_data_pages(void)
916 unsigned long pfn, max_zone_pfn;
919 for_each_zone(zone) {
920 if (is_highmem(zone))
923 mark_free_pages(zone);
924 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
925 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
926 if (saveable_page(zone, pfn))
932 /* This is needed, because copy_page and memcpy are not usable for copying
935 static inline void do_copy_page(long *dst, long *src)
939 for (n = PAGE_SIZE / sizeof(long); n; n--)
945 * safe_copy_page - check if the page we are going to copy is marked as
946 * present in the kernel page tables (this always is the case if
947 * CONFIG_DEBUG_PAGEALLOC is not set and in that case
948 * kernel_page_present() always returns 'true').
950 static void safe_copy_page(void *dst, struct page *s_page)
952 if (kernel_page_present(s_page)) {
953 do_copy_page(dst, page_address(s_page));
955 kernel_map_pages(s_page, 1, 1);
956 do_copy_page(dst, page_address(s_page));
957 kernel_map_pages(s_page, 1, 0);
962 #ifdef CONFIG_HIGHMEM
963 static inline struct page *
964 page_is_saveable(struct zone *zone, unsigned long pfn)
966 return is_highmem(zone) ?
967 saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
970 static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
972 struct page *s_page, *d_page;
975 s_page = pfn_to_page(src_pfn);
976 d_page = pfn_to_page(dst_pfn);
977 if (PageHighMem(s_page)) {
978 src = kmap_atomic(s_page, KM_USER0);
979 dst = kmap_atomic(d_page, KM_USER1);
980 do_copy_page(dst, src);
981 kunmap_atomic(src, KM_USER0);
982 kunmap_atomic(dst, KM_USER1);
984 if (PageHighMem(d_page)) {
985 /* Page pointed to by src may contain some kernel
986 * data modified by kmap_atomic()
988 safe_copy_page(buffer, s_page);
989 dst = kmap_atomic(d_page, KM_USER0);
990 memcpy(dst, buffer, PAGE_SIZE);
991 kunmap_atomic(dst, KM_USER0);
993 safe_copy_page(page_address(d_page), s_page);
998 #define page_is_saveable(zone, pfn) saveable_page(zone, pfn)
1000 static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1002 safe_copy_page(page_address(pfn_to_page(dst_pfn)),
1003 pfn_to_page(src_pfn));
1005 #endif /* CONFIG_HIGHMEM */
1008 copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
1013 for_each_zone(zone) {
1014 unsigned long max_zone_pfn;
1016 mark_free_pages(zone);
1017 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1018 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1019 if (page_is_saveable(zone, pfn))
1020 memory_bm_set_bit(orig_bm, pfn);
1022 memory_bm_position_reset(orig_bm);
1023 memory_bm_position_reset(copy_bm);
1025 pfn = memory_bm_next_pfn(orig_bm);
1026 if (unlikely(pfn == BM_END_OF_MAP))
1028 copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
1032 /* Total number of image pages */
1033 static unsigned int nr_copy_pages;
1034 /* Number of pages needed for saving the original pfns of the image pages */
1035 static unsigned int nr_meta_pages;
1038 * swsusp_free - free pages allocated for the suspend.
1040 * Suspend pages are alocated before the atomic copy is made, so we
1041 * need to release them after the resume.
1044 void swsusp_free(void)
1047 unsigned long pfn, max_zone_pfn;
1049 for_each_zone(zone) {
1050 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1051 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1052 if (pfn_valid(pfn)) {
1053 struct page *page = pfn_to_page(pfn);
1055 if (swsusp_page_is_forbidden(page) &&
1056 swsusp_page_is_free(page)) {
1057 swsusp_unset_page_forbidden(page);
1058 swsusp_unset_page_free(page);
1065 restore_pblist = NULL;
1069 /* Helper functions used for the shrinking of memory. */
1071 #define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN)
1074 * preallocate_image_pages - Allocate a number of pages for hibernation image
1075 * @nr_pages: Number of page frames to allocate.
1076 * @mask: GFP flags to use for the allocation.
1078 * Return value: Number of page frames actually allocated
1080 static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
1082 unsigned long nr_alloc = 0;
1084 while (nr_pages > 0) {
1085 if (!alloc_image_page(mask))
1094 static unsigned long preallocate_image_memory(unsigned long nr_pages)
1096 return preallocate_image_pages(nr_pages, GFP_IMAGE);
1099 #ifdef CONFIG_HIGHMEM
1100 static unsigned long preallocate_image_highmem(unsigned long nr_pages)
1102 return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
1106 * __fraction - Compute (an approximation of) x * (multiplier / base)
1108 static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
1112 return (unsigned long)x;
1115 static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1116 unsigned long highmem,
1117 unsigned long total)
1119 unsigned long alloc = __fraction(nr_pages, highmem, total);
1121 return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
1123 #else /* CONFIG_HIGHMEM */
1124 static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
1129 static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1130 unsigned long highmem,
1131 unsigned long total)
1135 #endif /* CONFIG_HIGHMEM */
1138 * swsusp_shrink_memory - Make the kernel release as much memory as needed
1140 * To create a hibernation image it is necessary to make a copy of every page
1141 * frame in use. We also need a number of page frames to be free during
1142 * hibernation for allocations made while saving the image and for device
1143 * drivers, in case they need to allocate memory from their hibernation
1144 * callbacks (these two numbers are given by PAGES_FOR_IO and SPARE_PAGES,
1145 * respectively, both of which are rough estimates). To make this happen, we
1146 * compute the total number of available page frames and allocate at least
1148 * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2 + 2 * SPARE_PAGES
1150 * of them, which corresponds to the maximum size of a hibernation image.
1152 * If image_size is set below the number following from the above formula,
1153 * the preallocation of memory is continued until the total number of saveable
1154 * pages in the system is below the requested image size or it is impossible to
1155 * allocate more memory, whichever happens first.
1157 int swsusp_shrink_memory(void)
1160 unsigned long saveable, size, max_size, count, highmem, pages = 0;
1161 unsigned long alloc, pages_highmem;
1162 struct timeval start, stop;
1165 printk(KERN_INFO "PM: Shrinking memory... ");
1166 do_gettimeofday(&start);
1168 /* Count the number of saveable data pages. */
1169 highmem = count_highmem_pages();
1170 saveable = count_data_pages();
1173 * Compute the total number of page frames we can use (count) and the
1174 * number of pages needed for image metadata (size).
1177 saveable += highmem;
1179 for_each_populated_zone(zone) {
1180 size += snapshot_additional_pages(zone);
1181 if (is_highmem(zone))
1182 highmem += zone_page_state(zone, NR_FREE_PAGES);
1184 count += zone_page_state(zone, NR_FREE_PAGES);
1187 count -= totalreserve_pages;
1189 /* Compute the maximum number of saveable pages to leave in memory. */
1190 max_size = (count - (size + PAGES_FOR_IO)) / 2 - 2 * SPARE_PAGES;
1191 size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1192 if (size > max_size)
1195 * If the maximum is not less than the current number of saveable pages
1196 * in memory, we don't need to do anything more.
1198 if (size >= saveable)
1202 * Let the memory management subsystem know that we're going to need a
1203 * large number of page frames to allocate and make it free some memory.
1204 * NOTE: If this is not done, performance will be hurt badly in some
1207 shrink_all_memory(saveable - size);
1210 * The number of saveable pages in memory was too high, so apply some
1211 * pressure to decrease it. First, make room for the largest possible
1212 * image and fail if that doesn't work. Next, try to decrease the size
1213 * of the image as much as indicated by image_size using allocations
1214 * from highmem and non-highmem zones separately.
1216 pages_highmem = preallocate_image_highmem(highmem / 2);
1217 alloc = (count - max_size) - pages_highmem;
1218 pages = preallocate_image_memory(alloc);
1219 if (pages < alloc) {
1223 size = max_size - size;
1225 size = preallocate_highmem_fraction(size, highmem, count);
1226 pages_highmem += size;
1228 pages += preallocate_image_memory(alloc);
1229 pages += pages_highmem;
1232 /* Release all of the preallocated page frames. */
1236 printk(KERN_CONT "\n");
1241 do_gettimeofday(&stop);
1242 printk(KERN_CONT "done (preallocated %lu free pages)\n", pages);
1243 swsusp_show_speed(&start, &stop, pages, "Freed");
1248 #ifdef CONFIG_HIGHMEM
1250 * count_pages_for_highmem - compute the number of non-highmem pages
1251 * that will be necessary for creating copies of highmem pages.
1254 static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
1256 unsigned int free_highmem = count_free_highmem_pages();
1258 if (free_highmem >= nr_highmem)
1261 nr_highmem -= free_highmem;
1267 count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
1268 #endif /* CONFIG_HIGHMEM */
1271 * enough_free_mem - Make sure we have enough free memory for the
1275 static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
1278 unsigned int free = 0, meta = 0;
1280 for_each_zone(zone) {
1281 meta += snapshot_additional_pages(zone);
1282 if (!is_highmem(zone))
1283 free += zone_page_state(zone, NR_FREE_PAGES);
1286 nr_pages += count_pages_for_highmem(nr_highmem);
1287 pr_debug("PM: Normal pages needed: %u + %u + %u, available pages: %u\n",
1288 nr_pages, PAGES_FOR_IO, meta, free);
1290 return free > nr_pages + PAGES_FOR_IO + meta;
1293 #ifdef CONFIG_HIGHMEM
1295 * get_highmem_buffer - if there are some highmem pages in the suspend
1296 * image, we may need the buffer to copy them and/or load their data.
1299 static inline int get_highmem_buffer(int safe_needed)
1301 buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
1302 return buffer ? 0 : -ENOMEM;
1306 * alloc_highmem_image_pages - allocate some highmem pages for the image.
1307 * Try to allocate as many pages as needed, but if the number of free
1308 * highmem pages is lesser than that, allocate them all.
1311 static inline unsigned int
1312 alloc_highmem_image_pages(struct memory_bitmap *bm, unsigned int nr_highmem)
1314 unsigned int to_alloc = count_free_highmem_pages();
1316 if (to_alloc > nr_highmem)
1317 to_alloc = nr_highmem;
1319 nr_highmem -= to_alloc;
1320 while (to_alloc-- > 0) {
1323 page = alloc_image_page(__GFP_HIGHMEM);
1324 memory_bm_set_bit(bm, page_to_pfn(page));
1329 static inline int get_highmem_buffer(int safe_needed) { return 0; }
1331 static inline unsigned int
1332 alloc_highmem_image_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }
1333 #endif /* CONFIG_HIGHMEM */
1336 * swsusp_alloc - allocate memory for the suspend image
1338 * We first try to allocate as many highmem pages as there are
1339 * saveable highmem pages in the system. If that fails, we allocate
1340 * non-highmem pages for the copies of the remaining highmem ones.
1342 * In this approach it is likely that the copies of highmem pages will
1343 * also be located in the high memory, because of the way in which
1344 * copy_data_pages() works.
1348 swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
1349 unsigned int nr_pages, unsigned int nr_highmem)
1353 error = memory_bm_create(orig_bm, GFP_ATOMIC | __GFP_COLD, PG_ANY);
1357 error = memory_bm_create(copy_bm, GFP_ATOMIC | __GFP_COLD, PG_ANY);
1361 if (nr_highmem > 0) {
1362 error = get_highmem_buffer(PG_ANY);
1366 nr_pages += alloc_highmem_image_pages(copy_bm, nr_highmem);
1368 while (nr_pages-- > 0) {
1369 struct page *page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
1374 memory_bm_set_bit(copy_bm, page_to_pfn(page));
1383 /* Memory bitmap used for marking saveable pages (during suspend) or the
1384 * suspend image pages (during resume)
1386 static struct memory_bitmap orig_bm;
1387 /* Memory bitmap used on suspend for marking allocated pages that will contain
1388 * the copies of saveable pages. During resume it is initially used for
1389 * marking the suspend image pages, but then its set bits are duplicated in
1390 * @orig_bm and it is released. Next, on systems with high memory, it may be
1391 * used for marking "safe" highmem pages, but it has to be reinitialized for
1394 static struct memory_bitmap copy_bm;
1396 asmlinkage int swsusp_save(void)
1398 unsigned int nr_pages, nr_highmem;
1400 printk(KERN_INFO "PM: Creating hibernation image: \n");
1402 drain_local_pages(NULL);
1403 nr_pages = count_data_pages();
1404 nr_highmem = count_highmem_pages();
1405 printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem);
1407 if (!enough_free_mem(nr_pages, nr_highmem)) {
1408 printk(KERN_ERR "PM: Not enough free memory\n");
1412 if (swsusp_alloc(&orig_bm, ©_bm, nr_pages, nr_highmem)) {
1413 printk(KERN_ERR "PM: Memory allocation failed\n");
1417 /* During allocating of suspend pagedir, new cold pages may appear.
1420 drain_local_pages(NULL);
1421 copy_data_pages(©_bm, &orig_bm);
1424 * End of critical section. From now on, we can write to memory,
1425 * but we should not touch disk. This specially means we must _not_
1426 * touch swap space! Except we must write out our image of course.
1429 nr_pages += nr_highmem;
1430 nr_copy_pages = nr_pages;
1431 nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
1433 printk(KERN_INFO "PM: Hibernation image created (%d pages copied)\n",
1439 #ifndef CONFIG_ARCH_HIBERNATION_HEADER
1440 static int init_header_complete(struct swsusp_info *info)
1442 memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
1443 info->version_code = LINUX_VERSION_CODE;
1447 static char *check_image_kernel(struct swsusp_info *info)
1449 if (info->version_code != LINUX_VERSION_CODE)
1450 return "kernel version";
1451 if (strcmp(info->uts.sysname,init_utsname()->sysname))
1452 return "system type";
1453 if (strcmp(info->uts.release,init_utsname()->release))
1454 return "kernel release";
1455 if (strcmp(info->uts.version,init_utsname()->version))
1457 if (strcmp(info->uts.machine,init_utsname()->machine))
1461 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */
1463 unsigned long snapshot_get_image_size(void)
1465 return nr_copy_pages + nr_meta_pages + 1;
1468 static int init_header(struct swsusp_info *info)
1470 memset(info, 0, sizeof(struct swsusp_info));
1471 info->num_physpages = num_physpages;
1472 info->image_pages = nr_copy_pages;
1473 info->pages = snapshot_get_image_size();
1474 info->size = info->pages;
1475 info->size <<= PAGE_SHIFT;
1476 return init_header_complete(info);
1480 * pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
1481 * are stored in the array @buf[] (1 page at a time)
1485 pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
1489 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1490 buf[j] = memory_bm_next_pfn(bm);
1491 if (unlikely(buf[j] == BM_END_OF_MAP))
1497 * snapshot_read_next - used for reading the system memory snapshot.
1499 * On the first call to it @handle should point to a zeroed
1500 * snapshot_handle structure. The structure gets updated and a pointer
1501 * to it should be passed to this function every next time.
1503 * The @count parameter should contain the number of bytes the caller
1504 * wants to read from the snapshot. It must not be zero.
1506 * On success the function returns a positive number. Then, the caller
1507 * is allowed to read up to the returned number of bytes from the memory
1508 * location computed by the data_of() macro. The number returned
1509 * may be smaller than @count, but this only happens if the read would
1510 * cross a page boundary otherwise.
1512 * The function returns 0 to indicate the end of data stream condition,
1513 * and a negative number is returned on error. In such cases the
1514 * structure pointed to by @handle is not updated and should not be used
1518 int snapshot_read_next(struct snapshot_handle *handle, size_t count)
1520 if (handle->cur > nr_meta_pages + nr_copy_pages)
1524 /* This makes the buffer be freed by swsusp_free() */
1525 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
1529 if (!handle->offset) {
1532 error = init_header((struct swsusp_info *)buffer);
1535 handle->buffer = buffer;
1536 memory_bm_position_reset(&orig_bm);
1537 memory_bm_position_reset(©_bm);
1539 if (handle->prev < handle->cur) {
1540 if (handle->cur <= nr_meta_pages) {
1541 memset(buffer, 0, PAGE_SIZE);
1542 pack_pfns(buffer, &orig_bm);
1546 page = pfn_to_page(memory_bm_next_pfn(©_bm));
1547 if (PageHighMem(page)) {
1548 /* Highmem pages are copied to the buffer,
1549 * because we can't return with a kmapped
1550 * highmem page (we may not be called again).
1554 kaddr = kmap_atomic(page, KM_USER0);
1555 memcpy(buffer, kaddr, PAGE_SIZE);
1556 kunmap_atomic(kaddr, KM_USER0);
1557 handle->buffer = buffer;
1559 handle->buffer = page_address(page);
1562 handle->prev = handle->cur;
1564 handle->buf_offset = handle->cur_offset;
1565 if (handle->cur_offset + count >= PAGE_SIZE) {
1566 count = PAGE_SIZE - handle->cur_offset;
1567 handle->cur_offset = 0;
1570 handle->cur_offset += count;
1572 handle->offset += count;
1577 * mark_unsafe_pages - mark the pages that cannot be used for storing
1578 * the image during resume, because they conflict with the pages that
1579 * had been used before suspend
1582 static int mark_unsafe_pages(struct memory_bitmap *bm)
1585 unsigned long pfn, max_zone_pfn;
1587 /* Clear page flags */
1588 for_each_zone(zone) {
1589 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1590 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1592 swsusp_unset_page_free(pfn_to_page(pfn));
1595 /* Mark pages that correspond to the "original" pfns as "unsafe" */
1596 memory_bm_position_reset(bm);
1598 pfn = memory_bm_next_pfn(bm);
1599 if (likely(pfn != BM_END_OF_MAP)) {
1600 if (likely(pfn_valid(pfn)))
1601 swsusp_set_page_free(pfn_to_page(pfn));
1605 } while (pfn != BM_END_OF_MAP);
1607 allocated_unsafe_pages = 0;
1613 duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
1617 memory_bm_position_reset(src);
1618 pfn = memory_bm_next_pfn(src);
1619 while (pfn != BM_END_OF_MAP) {
1620 memory_bm_set_bit(dst, pfn);
1621 pfn = memory_bm_next_pfn(src);
1625 static int check_header(struct swsusp_info *info)
1629 reason = check_image_kernel(info);
1630 if (!reason && info->num_physpages != num_physpages)
1631 reason = "memory size";
1633 printk(KERN_ERR "PM: Image mismatch: %s\n", reason);
1640 * load header - check the image header and copy data from it
1644 load_header(struct swsusp_info *info)
1648 restore_pblist = NULL;
1649 error = check_header(info);
1651 nr_copy_pages = info->image_pages;
1652 nr_meta_pages = info->pages - info->image_pages - 1;
1658 * unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
1659 * the corresponding bit in the memory bitmap @bm
1661 static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
1665 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1666 if (unlikely(buf[j] == BM_END_OF_MAP))
1669 if (memory_bm_pfn_present(bm, buf[j]))
1670 memory_bm_set_bit(bm, buf[j]);
1678 /* List of "safe" pages that may be used to store data loaded from the suspend
1681 static struct linked_page *safe_pages_list;
1683 #ifdef CONFIG_HIGHMEM
1684 /* struct highmem_pbe is used for creating the list of highmem pages that
1685 * should be restored atomically during the resume from disk, because the page
1686 * frames they have occupied before the suspend are in use.
1688 struct highmem_pbe {
1689 struct page *copy_page; /* data is here now */
1690 struct page *orig_page; /* data was here before the suspend */
1691 struct highmem_pbe *next;
1694 /* List of highmem PBEs needed for restoring the highmem pages that were
1695 * allocated before the suspend and included in the suspend image, but have
1696 * also been allocated by the "resume" kernel, so their contents cannot be
1697 * written directly to their "original" page frames.
1699 static struct highmem_pbe *highmem_pblist;
1702 * count_highmem_image_pages - compute the number of highmem pages in the
1703 * suspend image. The bits in the memory bitmap @bm that correspond to the
1704 * image pages are assumed to be set.
1707 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
1710 unsigned int cnt = 0;
1712 memory_bm_position_reset(bm);
1713 pfn = memory_bm_next_pfn(bm);
1714 while (pfn != BM_END_OF_MAP) {
1715 if (PageHighMem(pfn_to_page(pfn)))
1718 pfn = memory_bm_next_pfn(bm);
1724 * prepare_highmem_image - try to allocate as many highmem pages as
1725 * there are highmem image pages (@nr_highmem_p points to the variable
1726 * containing the number of highmem image pages). The pages that are
1727 * "safe" (ie. will not be overwritten when the suspend image is
1728 * restored) have the corresponding bits set in @bm (it must be
1731 * NOTE: This function should not be called if there are no highmem
1735 static unsigned int safe_highmem_pages;
1737 static struct memory_bitmap *safe_highmem_bm;
1740 prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
1742 unsigned int to_alloc;
1744 if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
1747 if (get_highmem_buffer(PG_SAFE))
1750 to_alloc = count_free_highmem_pages();
1751 if (to_alloc > *nr_highmem_p)
1752 to_alloc = *nr_highmem_p;
1754 *nr_highmem_p = to_alloc;
1756 safe_highmem_pages = 0;
1757 while (to_alloc-- > 0) {
1760 page = alloc_page(__GFP_HIGHMEM);
1761 if (!swsusp_page_is_free(page)) {
1762 /* The page is "safe", set its bit the bitmap */
1763 memory_bm_set_bit(bm, page_to_pfn(page));
1764 safe_highmem_pages++;
1766 /* Mark the page as allocated */
1767 swsusp_set_page_forbidden(page);
1768 swsusp_set_page_free(page);
1770 memory_bm_position_reset(bm);
1771 safe_highmem_bm = bm;
1776 * get_highmem_page_buffer - for given highmem image page find the buffer
1777 * that suspend_write_next() should set for its caller to write to.
1779 * If the page is to be saved to its "original" page frame or a copy of
1780 * the page is to be made in the highmem, @buffer is returned. Otherwise,
1781 * the copy of the page is to be made in normal memory, so the address of
1782 * the copy is returned.
1784 * If @buffer is returned, the caller of suspend_write_next() will write
1785 * the page's contents to @buffer, so they will have to be copied to the
1786 * right location on the next call to suspend_write_next() and it is done
1787 * with the help of copy_last_highmem_page(). For this purpose, if
1788 * @buffer is returned, @last_highmem page is set to the page to which
1789 * the data will have to be copied from @buffer.
1792 static struct page *last_highmem_page;
1795 get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
1797 struct highmem_pbe *pbe;
1800 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
1801 /* We have allocated the "original" page frame and we can
1802 * use it directly to store the loaded page.
1804 last_highmem_page = page;
1807 /* The "original" page frame has not been allocated and we have to
1808 * use a "safe" page frame to store the loaded page.
1810 pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
1813 return ERR_PTR(-ENOMEM);
1815 pbe->orig_page = page;
1816 if (safe_highmem_pages > 0) {
1819 /* Copy of the page will be stored in high memory */
1821 tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
1822 safe_highmem_pages--;
1823 last_highmem_page = tmp;
1824 pbe->copy_page = tmp;
1826 /* Copy of the page will be stored in normal memory */
1827 kaddr = safe_pages_list;
1828 safe_pages_list = safe_pages_list->next;
1829 pbe->copy_page = virt_to_page(kaddr);
1831 pbe->next = highmem_pblist;
1832 highmem_pblist = pbe;
1837 * copy_last_highmem_page - copy the contents of a highmem image from
1838 * @buffer, where the caller of snapshot_write_next() has place them,
1839 * to the right location represented by @last_highmem_page .
1842 static void copy_last_highmem_page(void)
1844 if (last_highmem_page) {
1847 dst = kmap_atomic(last_highmem_page, KM_USER0);
1848 memcpy(dst, buffer, PAGE_SIZE);
1849 kunmap_atomic(dst, KM_USER0);
1850 last_highmem_page = NULL;
1854 static inline int last_highmem_page_copied(void)
1856 return !last_highmem_page;
1859 static inline void free_highmem_data(void)
1861 if (safe_highmem_bm)
1862 memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
1865 free_image_page(buffer, PG_UNSAFE_CLEAR);
1868 static inline int get_safe_write_buffer(void) { return 0; }
1871 count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
1874 prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
1879 static inline void *
1880 get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
1882 return ERR_PTR(-EINVAL);
1885 static inline void copy_last_highmem_page(void) {}
1886 static inline int last_highmem_page_copied(void) { return 1; }
1887 static inline void free_highmem_data(void) {}
1888 #endif /* CONFIG_HIGHMEM */
1891 * prepare_image - use the memory bitmap @bm to mark the pages that will
1892 * be overwritten in the process of restoring the system memory state
1893 * from the suspend image ("unsafe" pages) and allocate memory for the
1896 * The idea is to allocate a new memory bitmap first and then allocate
1897 * as many pages as needed for the image data, but not to assign these
1898 * pages to specific tasks initially. Instead, we just mark them as
1899 * allocated and create a lists of "safe" pages that will be used
1900 * later. On systems with high memory a list of "safe" highmem pages is
1904 #define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
1907 prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
1909 unsigned int nr_pages, nr_highmem;
1910 struct linked_page *sp_list, *lp;
1913 /* If there is no highmem, the buffer will not be necessary */
1914 free_image_page(buffer, PG_UNSAFE_CLEAR);
1917 nr_highmem = count_highmem_image_pages(bm);
1918 error = mark_unsafe_pages(bm);
1922 error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
1926 duplicate_memory_bitmap(new_bm, bm);
1927 memory_bm_free(bm, PG_UNSAFE_KEEP);
1928 if (nr_highmem > 0) {
1929 error = prepare_highmem_image(bm, &nr_highmem);
1933 /* Reserve some safe pages for potential later use.
1935 * NOTE: This way we make sure there will be enough safe pages for the
1936 * chain_alloc() in get_buffer(). It is a bit wasteful, but
1937 * nr_copy_pages cannot be greater than 50% of the memory anyway.
1940 /* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
1941 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
1942 nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
1943 while (nr_pages > 0) {
1944 lp = get_image_page(GFP_ATOMIC, PG_SAFE);
1953 /* Preallocate memory for the image */
1954 safe_pages_list = NULL;
1955 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
1956 while (nr_pages > 0) {
1957 lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
1962 if (!swsusp_page_is_free(virt_to_page(lp))) {
1963 /* The page is "safe", add it to the list */
1964 lp->next = safe_pages_list;
1965 safe_pages_list = lp;
1967 /* Mark the page as allocated */
1968 swsusp_set_page_forbidden(virt_to_page(lp));
1969 swsusp_set_page_free(virt_to_page(lp));
1972 /* Free the reserved safe pages so that chain_alloc() can use them */
1975 free_image_page(sp_list, PG_UNSAFE_CLEAR);
1986 * get_buffer - compute the address that snapshot_write_next() should
1987 * set for its caller to write to.
1990 static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
1994 unsigned long pfn = memory_bm_next_pfn(bm);
1996 if (pfn == BM_END_OF_MAP)
1997 return ERR_PTR(-EFAULT);
1999 page = pfn_to_page(pfn);
2000 if (PageHighMem(page))
2001 return get_highmem_page_buffer(page, ca);
2003 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
2004 /* We have allocated the "original" page frame and we can
2005 * use it directly to store the loaded page.
2007 return page_address(page);
2009 /* The "original" page frame has not been allocated and we have to
2010 * use a "safe" page frame to store the loaded page.
2012 pbe = chain_alloc(ca, sizeof(struct pbe));
2015 return ERR_PTR(-ENOMEM);
2017 pbe->orig_address = page_address(page);
2018 pbe->address = safe_pages_list;
2019 safe_pages_list = safe_pages_list->next;
2020 pbe->next = restore_pblist;
2021 restore_pblist = pbe;
2022 return pbe->address;
2026 * snapshot_write_next - used for writing the system memory snapshot.
2028 * On the first call to it @handle should point to a zeroed
2029 * snapshot_handle structure. The structure gets updated and a pointer
2030 * to it should be passed to this function every next time.
2032 * The @count parameter should contain the number of bytes the caller
2033 * wants to write to the image. It must not be zero.
2035 * On success the function returns a positive number. Then, the caller
2036 * is allowed to write up to the returned number of bytes to the memory
2037 * location computed by the data_of() macro. The number returned
2038 * may be smaller than @count, but this only happens if the write would
2039 * cross a page boundary otherwise.
2041 * The function returns 0 to indicate the "end of file" condition,
2042 * and a negative number is returned on error. In such cases the
2043 * structure pointed to by @handle is not updated and should not be used
2047 int snapshot_write_next(struct snapshot_handle *handle, size_t count)
2049 static struct chain_allocator ca;
2052 /* Check if we have already loaded the entire image */
2053 if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages)
2056 if (handle->offset == 0) {
2058 /* This makes the buffer be freed by swsusp_free() */
2059 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2064 handle->buffer = buffer;
2066 handle->sync_read = 1;
2067 if (handle->prev < handle->cur) {
2068 if (handle->prev == 0) {
2069 error = load_header(buffer);
2073 error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
2077 } else if (handle->prev <= nr_meta_pages) {
2078 error = unpack_orig_pfns(buffer, ©_bm);
2082 if (handle->prev == nr_meta_pages) {
2083 error = prepare_image(&orig_bm, ©_bm);
2087 chain_init(&ca, GFP_ATOMIC, PG_SAFE);
2088 memory_bm_position_reset(&orig_bm);
2089 restore_pblist = NULL;
2090 handle->buffer = get_buffer(&orig_bm, &ca);
2091 handle->sync_read = 0;
2092 if (IS_ERR(handle->buffer))
2093 return PTR_ERR(handle->buffer);
2096 copy_last_highmem_page();
2097 handle->buffer = get_buffer(&orig_bm, &ca);
2098 if (IS_ERR(handle->buffer))
2099 return PTR_ERR(handle->buffer);
2100 if (handle->buffer != buffer)
2101 handle->sync_read = 0;
2103 handle->prev = handle->cur;
2105 handle->buf_offset = handle->cur_offset;
2106 if (handle->cur_offset + count >= PAGE_SIZE) {
2107 count = PAGE_SIZE - handle->cur_offset;
2108 handle->cur_offset = 0;
2111 handle->cur_offset += count;
2113 handle->offset += count;
2118 * snapshot_write_finalize - must be called after the last call to
2119 * snapshot_write_next() in case the last page in the image happens
2120 * to be a highmem page and its contents should be stored in the
2121 * highmem. Additionally, it releases the memory that will not be
2125 void snapshot_write_finalize(struct snapshot_handle *handle)
2127 copy_last_highmem_page();
2128 /* Free only if we have loaded the image entirely */
2129 if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages) {
2130 memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
2131 free_highmem_data();
2135 int snapshot_image_loaded(struct snapshot_handle *handle)
2137 return !(!nr_copy_pages || !last_highmem_page_copied() ||
2138 handle->cur <= nr_meta_pages + nr_copy_pages);
2141 #ifdef CONFIG_HIGHMEM
2142 /* Assumes that @buf is ready and points to a "safe" page */
2144 swap_two_pages_data(struct page *p1, struct page *p2, void *buf)
2146 void *kaddr1, *kaddr2;
2148 kaddr1 = kmap_atomic(p1, KM_USER0);
2149 kaddr2 = kmap_atomic(p2, KM_USER1);
2150 memcpy(buf, kaddr1, PAGE_SIZE);
2151 memcpy(kaddr1, kaddr2, PAGE_SIZE);
2152 memcpy(kaddr2, buf, PAGE_SIZE);
2153 kunmap_atomic(kaddr1, KM_USER0);
2154 kunmap_atomic(kaddr2, KM_USER1);
2158 * restore_highmem - for each highmem page that was allocated before
2159 * the suspend and included in the suspend image, and also has been
2160 * allocated by the "resume" kernel swap its current (ie. "before
2161 * resume") contents with the previous (ie. "before suspend") one.
2163 * If the resume eventually fails, we can call this function once
2164 * again and restore the "before resume" highmem state.
2167 int restore_highmem(void)
2169 struct highmem_pbe *pbe = highmem_pblist;
2175 buf = get_image_page(GFP_ATOMIC, PG_SAFE);
2180 swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
2183 free_image_page(buf, PG_UNSAFE_CLEAR);
2186 #endif /* CONFIG_HIGHMEM */