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>
29 #include <asm/uaccess.h>
30 #include <asm/mmu_context.h>
31 #include <asm/pgtable.h>
32 #include <asm/tlbflush.h>
37 static int swsusp_page_is_free(struct page *);
38 static void swsusp_set_page_forbidden(struct page *);
39 static void swsusp_unset_page_forbidden(struct page *);
41 /* List of PBEs needed for restoring the pages that were allocated before
42 * the suspend and included in the suspend image, but have also been
43 * allocated by the "resume" kernel, so their contents cannot be written
44 * directly to their "original" page frames.
46 struct pbe *restore_pblist;
48 /* Pointer to an auxiliary buffer (1 page) */
52 * @safe_needed - on resume, for storing the PBE list and the image,
53 * we can only use memory pages that do not conflict with the pages
54 * used before suspend. The unsafe pages have PageNosaveFree set
55 * and we count them using unsafe_pages.
57 * Each allocated image page is marked as PageNosave and PageNosaveFree
58 * so that swsusp_free() can release it.
63 #define PG_UNSAFE_CLEAR 1
64 #define PG_UNSAFE_KEEP 0
66 static unsigned int allocated_unsafe_pages;
68 static void *get_image_page(gfp_t gfp_mask, int safe_needed)
72 res = (void *)get_zeroed_page(gfp_mask);
74 while (res && swsusp_page_is_free(virt_to_page(res))) {
75 /* The page is unsafe, mark it for swsusp_free() */
76 swsusp_set_page_forbidden(virt_to_page(res));
77 allocated_unsafe_pages++;
78 res = (void *)get_zeroed_page(gfp_mask);
81 swsusp_set_page_forbidden(virt_to_page(res));
82 swsusp_set_page_free(virt_to_page(res));
87 unsigned long get_safe_page(gfp_t gfp_mask)
89 return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
92 static struct page *alloc_image_page(gfp_t gfp_mask)
96 page = alloc_page(gfp_mask);
98 swsusp_set_page_forbidden(page);
99 swsusp_set_page_free(page);
105 * free_image_page - free page represented by @addr, allocated with
106 * get_image_page (page flags set by it must be cleared)
109 static inline void free_image_page(void *addr, int clear_nosave_free)
113 BUG_ON(!virt_addr_valid(addr));
115 page = virt_to_page(addr);
117 swsusp_unset_page_forbidden(page);
118 if (clear_nosave_free)
119 swsusp_unset_page_free(page);
124 /* struct linked_page is used to build chains of pages */
126 #define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *))
129 struct linked_page *next;
130 char data[LINKED_PAGE_DATA_SIZE];
131 } __attribute__((packed));
134 free_list_of_pages(struct linked_page *list, int clear_page_nosave)
137 struct linked_page *lp = list->next;
139 free_image_page(list, clear_page_nosave);
145 * struct chain_allocator is used for allocating small objects out of
146 * a linked list of pages called 'the chain'.
148 * The chain grows each time when there is no room for a new object in
149 * the current page. The allocated objects cannot be freed individually.
150 * It is only possible to free them all at once, by freeing the entire
153 * NOTE: The chain allocator may be inefficient if the allocated objects
154 * are not much smaller than PAGE_SIZE.
157 struct chain_allocator {
158 struct linked_page *chain; /* the chain */
159 unsigned int used_space; /* total size of objects allocated out
160 * of the current page
162 gfp_t gfp_mask; /* mask for allocating pages */
163 int safe_needed; /* if set, only "safe" pages are allocated */
167 chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed)
170 ca->used_space = LINKED_PAGE_DATA_SIZE;
171 ca->gfp_mask = gfp_mask;
172 ca->safe_needed = safe_needed;
175 static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
179 if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
180 struct linked_page *lp;
182 lp = get_image_page(ca->gfp_mask, ca->safe_needed);
186 lp->next = ca->chain;
190 ret = ca->chain->data + ca->used_space;
191 ca->used_space += size;
195 static void chain_free(struct chain_allocator *ca, int clear_page_nosave)
197 free_list_of_pages(ca->chain, clear_page_nosave);
198 memset(ca, 0, sizeof(struct chain_allocator));
202 * Data types related to memory bitmaps.
204 * Memory bitmap is a structure consiting of many linked lists of
205 * objects. The main list's elements are of type struct zone_bitmap
206 * and each of them corresonds to one zone. For each zone bitmap
207 * object there is a list of objects of type struct bm_block that
208 * represent each blocks of bitmap in which information is stored.
210 * struct memory_bitmap contains a pointer to the main list of zone
211 * bitmap objects, a struct bm_position used for browsing the bitmap,
212 * and a pointer to the list of pages used for allocating all of the
213 * zone bitmap objects and bitmap block objects.
215 * NOTE: It has to be possible to lay out the bitmap in memory
216 * using only allocations of order 0. Additionally, the bitmap is
217 * designed to work with arbitrary number of zones (this is over the
218 * top for now, but let's avoid making unnecessary assumptions ;-).
220 * struct zone_bitmap contains a pointer to a list of bitmap block
221 * objects and a pointer to the bitmap block object that has been
222 * most recently used for setting bits. Additionally, it contains the
223 * pfns that correspond to the start and end of the represented zone.
225 * struct bm_block contains a pointer to the memory page in which
226 * information is stored (in the form of a block of bitmap)
227 * It also contains the pfns that correspond to the start and end of
228 * the represented memory area.
231 #define BM_END_OF_MAP (~0UL)
233 #define BM_BITS_PER_BLOCK (PAGE_SIZE << 3)
236 struct bm_block *next; /* next element of the list */
237 unsigned long start_pfn; /* pfn represented by the first bit */
238 unsigned long end_pfn; /* pfn represented by the last bit plus 1 */
239 unsigned long *data; /* bitmap representing pages */
242 static inline unsigned long bm_block_bits(struct bm_block *bb)
244 return bb->end_pfn - bb->start_pfn;
248 struct zone_bitmap *next; /* next element of the list */
249 unsigned long start_pfn; /* minimal pfn in this zone */
250 unsigned long end_pfn; /* maximal pfn in this zone plus 1 */
251 struct bm_block *bm_blocks; /* list of bitmap blocks */
252 struct bm_block *cur_block; /* recently used bitmap block */
255 /* strcut bm_position is used for browsing memory bitmaps */
258 struct zone_bitmap *zone_bm;
259 struct bm_block *block;
263 struct memory_bitmap {
264 struct zone_bitmap *zone_bm_list; /* list of zone bitmaps */
265 struct linked_page *p_list; /* list of pages used to store zone
266 * bitmap objects and bitmap block
269 struct bm_position cur; /* most recently used bit position */
272 /* Functions that operate on memory bitmaps */
274 static void memory_bm_position_reset(struct memory_bitmap *bm)
276 struct zone_bitmap *zone_bm;
278 zone_bm = bm->zone_bm_list;
279 bm->cur.zone_bm = zone_bm;
280 bm->cur.block = zone_bm->bm_blocks;
284 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
287 * create_bm_block_list - create a list of block bitmap objects
290 static inline struct bm_block *
291 create_bm_block_list(unsigned int nr_blocks, struct chain_allocator *ca)
293 struct bm_block *bblist = NULL;
295 while (nr_blocks-- > 0) {
298 bb = chain_alloc(ca, sizeof(struct bm_block));
309 * create_zone_bm_list - create a list of zone bitmap objects
312 static inline struct zone_bitmap *
313 create_zone_bm_list(unsigned int nr_zones, struct chain_allocator *ca)
315 struct zone_bitmap *zbmlist = NULL;
317 while (nr_zones-- > 0) {
318 struct zone_bitmap *zbm;
320 zbm = chain_alloc(ca, sizeof(struct zone_bitmap));
331 * memory_bm_create - allocate memory for a memory bitmap
335 memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
337 struct chain_allocator ca;
339 struct zone_bitmap *zone_bm;
343 chain_init(&ca, gfp_mask, safe_needed);
345 /* Compute the number of zones */
348 if (populated_zone(zone))
351 /* Allocate the list of zones bitmap objects */
352 zone_bm = create_zone_bm_list(nr, &ca);
353 bm->zone_bm_list = zone_bm;
355 chain_free(&ca, PG_UNSAFE_CLEAR);
359 /* Initialize the zone bitmap objects */
360 for_each_zone(zone) {
363 if (!populated_zone(zone))
366 zone_bm->start_pfn = zone->zone_start_pfn;
367 zone_bm->end_pfn = zone->zone_start_pfn + zone->spanned_pages;
368 /* Allocate the list of bitmap block objects */
369 nr = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
370 bb = create_bm_block_list(nr, &ca);
371 zone_bm->bm_blocks = bb;
372 zone_bm->cur_block = bb;
376 nr = zone->spanned_pages;
377 pfn = zone->zone_start_pfn;
378 /* Initialize the bitmap block objects */
382 ptr = get_image_page(gfp_mask, safe_needed);
388 if (nr >= BM_BITS_PER_BLOCK) {
389 pfn += BM_BITS_PER_BLOCK;
390 nr -= BM_BITS_PER_BLOCK;
392 /* This is executed only once in the loop */
398 zone_bm = zone_bm->next;
400 bm->p_list = ca.chain;
401 memory_bm_position_reset(bm);
405 bm->p_list = ca.chain;
406 memory_bm_free(bm, PG_UNSAFE_CLEAR);
411 * memory_bm_free - free memory occupied by the memory bitmap @bm
414 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
416 struct zone_bitmap *zone_bm;
418 /* Free the list of bit blocks for each zone_bitmap object */
419 zone_bm = bm->zone_bm_list;
423 bb = zone_bm->bm_blocks;
426 free_image_page(bb->data, clear_nosave_free);
429 zone_bm = zone_bm->next;
431 free_list_of_pages(bm->p_list, clear_nosave_free);
432 bm->zone_bm_list = NULL;
436 * memory_bm_find_bit - find the bit in the bitmap @bm that corresponds
437 * to given pfn. The cur_zone_bm member of @bm and the cur_block member
438 * of @bm->cur_zone_bm are updated.
441 static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
442 void **addr, unsigned int *bit_nr)
444 struct zone_bitmap *zone_bm;
447 /* Check if the pfn is from the current zone */
448 zone_bm = bm->cur.zone_bm;
449 if (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {
450 zone_bm = bm->zone_bm_list;
451 /* We don't assume that the zones are sorted by pfns */
452 while (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {
453 zone_bm = zone_bm->next;
458 bm->cur.zone_bm = zone_bm;
460 /* Check if the pfn corresponds to the current bitmap block */
461 bb = zone_bm->cur_block;
462 if (pfn < bb->start_pfn)
463 bb = zone_bm->bm_blocks;
465 while (pfn >= bb->end_pfn) {
470 zone_bm->cur_block = bb;
471 pfn -= bb->start_pfn;
477 static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
483 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
488 static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
494 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
500 static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
506 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
508 clear_bit(bit, addr);
511 static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
517 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
519 return test_bit(bit, addr);
522 static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
527 return !memory_bm_find_bit(bm, pfn, &addr, &bit);
531 * memory_bm_next_pfn - find the pfn that corresponds to the next set bit
532 * in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is
535 * It is required to run memory_bm_position_reset() before the first call to
539 static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
541 struct zone_bitmap *zone_bm;
549 bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
550 if (bit < bm_block_bits(bb))
557 zone_bm = bm->cur.zone_bm->next;
559 bm->cur.zone_bm = zone_bm;
560 bm->cur.block = zone_bm->bm_blocks;
564 memory_bm_position_reset(bm);
565 return BM_END_OF_MAP;
568 bm->cur.bit = bit + 1;
569 return bb->start_pfn + bit;
573 * This structure represents a range of page frames the contents of which
574 * should not be saved during the suspend.
577 struct nosave_region {
578 struct list_head list;
579 unsigned long start_pfn;
580 unsigned long end_pfn;
583 static LIST_HEAD(nosave_regions);
586 * register_nosave_region - register a range of page frames the contents
587 * of which should not be saved during the suspend (to be used in the early
588 * initialization code)
592 __register_nosave_region(unsigned long start_pfn, unsigned long end_pfn,
595 struct nosave_region *region;
597 if (start_pfn >= end_pfn)
600 if (!list_empty(&nosave_regions)) {
601 /* Try to extend the previous region (they should be sorted) */
602 region = list_entry(nosave_regions.prev,
603 struct nosave_region, list);
604 if (region->end_pfn == start_pfn) {
605 region->end_pfn = end_pfn;
610 /* during init, this shouldn't fail */
611 region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
614 /* This allocation cannot fail */
615 region = alloc_bootmem_low(sizeof(struct nosave_region));
616 region->start_pfn = start_pfn;
617 region->end_pfn = end_pfn;
618 list_add_tail(®ion->list, &nosave_regions);
620 printk(KERN_INFO "PM: Registered nosave memory: %016lx - %016lx\n",
621 start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT);
625 * Set bits in this map correspond to the page frames the contents of which
626 * should not be saved during the suspend.
628 static struct memory_bitmap *forbidden_pages_map;
630 /* Set bits in this map correspond to free page frames. */
631 static struct memory_bitmap *free_pages_map;
634 * Each page frame allocated for creating the image is marked by setting the
635 * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
638 void swsusp_set_page_free(struct page *page)
641 memory_bm_set_bit(free_pages_map, page_to_pfn(page));
644 static int swsusp_page_is_free(struct page *page)
646 return free_pages_map ?
647 memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
650 void swsusp_unset_page_free(struct page *page)
653 memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
656 static void swsusp_set_page_forbidden(struct page *page)
658 if (forbidden_pages_map)
659 memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
662 int swsusp_page_is_forbidden(struct page *page)
664 return forbidden_pages_map ?
665 memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
668 static void swsusp_unset_page_forbidden(struct page *page)
670 if (forbidden_pages_map)
671 memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
675 * mark_nosave_pages - set bits corresponding to the page frames the
676 * contents of which should not be saved in a given bitmap.
679 static void mark_nosave_pages(struct memory_bitmap *bm)
681 struct nosave_region *region;
683 if (list_empty(&nosave_regions))
686 list_for_each_entry(region, &nosave_regions, list) {
689 pr_debug("PM: Marking nosave pages: %016lx - %016lx\n",
690 region->start_pfn << PAGE_SHIFT,
691 region->end_pfn << PAGE_SHIFT);
693 for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
694 if (pfn_valid(pfn)) {
696 * It is safe to ignore the result of
697 * mem_bm_set_bit_check() here, since we won't
698 * touch the PFNs for which the error is
701 mem_bm_set_bit_check(bm, pfn);
707 * create_basic_memory_bitmaps - create bitmaps needed for marking page
708 * frames that should not be saved and free page frames. The pointers
709 * forbidden_pages_map and free_pages_map are only modified if everything
710 * goes well, because we don't want the bits to be used before both bitmaps
714 int create_basic_memory_bitmaps(void)
716 struct memory_bitmap *bm1, *bm2;
719 BUG_ON(forbidden_pages_map || free_pages_map);
721 bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
725 error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
727 goto Free_first_object;
729 bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
731 goto Free_first_bitmap;
733 error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
735 goto Free_second_object;
737 forbidden_pages_map = bm1;
738 free_pages_map = bm2;
739 mark_nosave_pages(forbidden_pages_map);
741 pr_debug("PM: Basic memory bitmaps created\n");
748 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
755 * free_basic_memory_bitmaps - free memory bitmaps allocated by
756 * create_basic_memory_bitmaps(). The auxiliary pointers are necessary
757 * so that the bitmaps themselves are not referred to while they are being
761 void free_basic_memory_bitmaps(void)
763 struct memory_bitmap *bm1, *bm2;
765 BUG_ON(!(forbidden_pages_map && free_pages_map));
767 bm1 = forbidden_pages_map;
768 bm2 = free_pages_map;
769 forbidden_pages_map = NULL;
770 free_pages_map = NULL;
771 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
773 memory_bm_free(bm2, PG_UNSAFE_CLEAR);
776 pr_debug("PM: Basic memory bitmaps freed\n");
780 * snapshot_additional_pages - estimate the number of additional pages
781 * be needed for setting up the suspend image data structures for given
782 * zone (usually the returned value is greater than the exact number)
785 unsigned int snapshot_additional_pages(struct zone *zone)
789 res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
790 res += DIV_ROUND_UP(res * sizeof(struct bm_block), PAGE_SIZE);
794 #ifdef CONFIG_HIGHMEM
796 * count_free_highmem_pages - compute the total number of free highmem
797 * pages, system-wide.
800 static unsigned int count_free_highmem_pages(void)
803 unsigned int cnt = 0;
806 if (populated_zone(zone) && is_highmem(zone))
807 cnt += zone_page_state(zone, NR_FREE_PAGES);
813 * saveable_highmem_page - Determine whether a highmem page should be
814 * included in the suspend image.
816 * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
817 * and it isn't a part of a free chunk of pages.
820 static struct page *saveable_highmem_page(unsigned long pfn)
827 page = pfn_to_page(pfn);
829 BUG_ON(!PageHighMem(page));
831 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page) ||
839 * count_highmem_pages - compute the total number of saveable highmem
843 unsigned int count_highmem_pages(void)
848 for_each_zone(zone) {
849 unsigned long pfn, max_zone_pfn;
851 if (!is_highmem(zone))
854 mark_free_pages(zone);
855 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
856 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
857 if (saveable_highmem_page(pfn))
863 static inline void *saveable_highmem_page(unsigned long pfn) { return NULL; }
864 #endif /* CONFIG_HIGHMEM */
867 * saveable_page - Determine whether a non-highmem page should be included
868 * in the suspend image.
870 * We should save the page if it isn't Nosave, and is not in the range
871 * of pages statically defined as 'unsaveable', and it isn't a part of
872 * a free chunk of pages.
875 static struct page *saveable_page(unsigned long pfn)
882 page = pfn_to_page(pfn);
884 BUG_ON(PageHighMem(page));
886 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
889 if (PageReserved(page)
890 && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
897 * count_data_pages - compute the total number of saveable non-highmem
901 unsigned int count_data_pages(void)
904 unsigned long pfn, max_zone_pfn;
907 for_each_zone(zone) {
908 if (is_highmem(zone))
911 mark_free_pages(zone);
912 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
913 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
914 if(saveable_page(pfn))
920 /* This is needed, because copy_page and memcpy are not usable for copying
923 static inline void do_copy_page(long *dst, long *src)
927 for (n = PAGE_SIZE / sizeof(long); n; n--)
933 * safe_copy_page - check if the page we are going to copy is marked as
934 * present in the kernel page tables (this always is the case if
935 * CONFIG_DEBUG_PAGEALLOC is not set and in that case
936 * kernel_page_present() always returns 'true').
938 static void safe_copy_page(void *dst, struct page *s_page)
940 if (kernel_page_present(s_page)) {
941 do_copy_page(dst, page_address(s_page));
943 kernel_map_pages(s_page, 1, 1);
944 do_copy_page(dst, page_address(s_page));
945 kernel_map_pages(s_page, 1, 0);
950 #ifdef CONFIG_HIGHMEM
951 static inline struct page *
952 page_is_saveable(struct zone *zone, unsigned long pfn)
954 return is_highmem(zone) ?
955 saveable_highmem_page(pfn) : saveable_page(pfn);
958 static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
960 struct page *s_page, *d_page;
963 s_page = pfn_to_page(src_pfn);
964 d_page = pfn_to_page(dst_pfn);
965 if (PageHighMem(s_page)) {
966 src = kmap_atomic(s_page, KM_USER0);
967 dst = kmap_atomic(d_page, KM_USER1);
968 do_copy_page(dst, src);
969 kunmap_atomic(src, KM_USER0);
970 kunmap_atomic(dst, KM_USER1);
972 if (PageHighMem(d_page)) {
973 /* Page pointed to by src may contain some kernel
974 * data modified by kmap_atomic()
976 safe_copy_page(buffer, s_page);
977 dst = kmap_atomic(pfn_to_page(dst_pfn), KM_USER0);
978 memcpy(dst, buffer, PAGE_SIZE);
979 kunmap_atomic(dst, KM_USER0);
981 safe_copy_page(page_address(d_page), s_page);
986 #define page_is_saveable(zone, pfn) saveable_page(pfn)
988 static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
990 safe_copy_page(page_address(pfn_to_page(dst_pfn)),
991 pfn_to_page(src_pfn));
993 #endif /* CONFIG_HIGHMEM */
996 copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
1001 for_each_zone(zone) {
1002 unsigned long max_zone_pfn;
1004 mark_free_pages(zone);
1005 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1006 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1007 if (page_is_saveable(zone, pfn))
1008 memory_bm_set_bit(orig_bm, pfn);
1010 memory_bm_position_reset(orig_bm);
1011 memory_bm_position_reset(copy_bm);
1013 pfn = memory_bm_next_pfn(orig_bm);
1014 if (unlikely(pfn == BM_END_OF_MAP))
1016 copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
1020 /* Total number of image pages */
1021 static unsigned int nr_copy_pages;
1022 /* Number of pages needed for saving the original pfns of the image pages */
1023 static unsigned int nr_meta_pages;
1026 * swsusp_free - free pages allocated for the suspend.
1028 * Suspend pages are alocated before the atomic copy is made, so we
1029 * need to release them after the resume.
1032 void swsusp_free(void)
1035 unsigned long pfn, max_zone_pfn;
1037 for_each_zone(zone) {
1038 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1039 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1040 if (pfn_valid(pfn)) {
1041 struct page *page = pfn_to_page(pfn);
1043 if (swsusp_page_is_forbidden(page) &&
1044 swsusp_page_is_free(page)) {
1045 swsusp_unset_page_forbidden(page);
1046 swsusp_unset_page_free(page);
1053 restore_pblist = NULL;
1057 #ifdef CONFIG_HIGHMEM
1059 * count_pages_for_highmem - compute the number of non-highmem pages
1060 * that will be necessary for creating copies of highmem pages.
1063 static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
1065 unsigned int free_highmem = count_free_highmem_pages();
1067 if (free_highmem >= nr_highmem)
1070 nr_highmem -= free_highmem;
1076 count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
1077 #endif /* CONFIG_HIGHMEM */
1080 * enough_free_mem - Make sure we have enough free memory for the
1084 static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
1087 unsigned int free = 0, meta = 0;
1089 for_each_zone(zone) {
1090 meta += snapshot_additional_pages(zone);
1091 if (!is_highmem(zone))
1092 free += zone_page_state(zone, NR_FREE_PAGES);
1095 nr_pages += count_pages_for_highmem(nr_highmem);
1096 pr_debug("PM: Normal pages needed: %u + %u + %u, available pages: %u\n",
1097 nr_pages, PAGES_FOR_IO, meta, free);
1099 return free > nr_pages + PAGES_FOR_IO + meta;
1102 #ifdef CONFIG_HIGHMEM
1104 * get_highmem_buffer - if there are some highmem pages in the suspend
1105 * image, we may need the buffer to copy them and/or load their data.
1108 static inline int get_highmem_buffer(int safe_needed)
1110 buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
1111 return buffer ? 0 : -ENOMEM;
1115 * alloc_highmem_image_pages - allocate some highmem pages for the image.
1116 * Try to allocate as many pages as needed, but if the number of free
1117 * highmem pages is lesser than that, allocate them all.
1120 static inline unsigned int
1121 alloc_highmem_image_pages(struct memory_bitmap *bm, unsigned int nr_highmem)
1123 unsigned int to_alloc = count_free_highmem_pages();
1125 if (to_alloc > nr_highmem)
1126 to_alloc = nr_highmem;
1128 nr_highmem -= to_alloc;
1129 while (to_alloc-- > 0) {
1132 page = alloc_image_page(__GFP_HIGHMEM);
1133 memory_bm_set_bit(bm, page_to_pfn(page));
1138 static inline int get_highmem_buffer(int safe_needed) { return 0; }
1140 static inline unsigned int
1141 alloc_highmem_image_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }
1142 #endif /* CONFIG_HIGHMEM */
1145 * swsusp_alloc - allocate memory for the suspend image
1147 * We first try to allocate as many highmem pages as there are
1148 * saveable highmem pages in the system. If that fails, we allocate
1149 * non-highmem pages for the copies of the remaining highmem ones.
1151 * In this approach it is likely that the copies of highmem pages will
1152 * also be located in the high memory, because of the way in which
1153 * copy_data_pages() works.
1157 swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
1158 unsigned int nr_pages, unsigned int nr_highmem)
1162 error = memory_bm_create(orig_bm, GFP_ATOMIC | __GFP_COLD, PG_ANY);
1166 error = memory_bm_create(copy_bm, GFP_ATOMIC | __GFP_COLD, PG_ANY);
1170 if (nr_highmem > 0) {
1171 error = get_highmem_buffer(PG_ANY);
1175 nr_pages += alloc_highmem_image_pages(copy_bm, nr_highmem);
1177 while (nr_pages-- > 0) {
1178 struct page *page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
1183 memory_bm_set_bit(copy_bm, page_to_pfn(page));
1192 /* Memory bitmap used for marking saveable pages (during suspend) or the
1193 * suspend image pages (during resume)
1195 static struct memory_bitmap orig_bm;
1196 /* Memory bitmap used on suspend for marking allocated pages that will contain
1197 * the copies of saveable pages. During resume it is initially used for
1198 * marking the suspend image pages, but then its set bits are duplicated in
1199 * @orig_bm and it is released. Next, on systems with high memory, it may be
1200 * used for marking "safe" highmem pages, but it has to be reinitialized for
1203 static struct memory_bitmap copy_bm;
1205 asmlinkage int swsusp_save(void)
1207 unsigned int nr_pages, nr_highmem;
1209 printk(KERN_INFO "PM: Creating hibernation image: \n");
1211 drain_local_pages(NULL);
1212 nr_pages = count_data_pages();
1213 nr_highmem = count_highmem_pages();
1214 printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem);
1216 if (!enough_free_mem(nr_pages, nr_highmem)) {
1217 printk(KERN_ERR "PM: Not enough free memory\n");
1221 if (swsusp_alloc(&orig_bm, ©_bm, nr_pages, nr_highmem)) {
1222 printk(KERN_ERR "PM: Memory allocation failed\n");
1226 /* During allocating of suspend pagedir, new cold pages may appear.
1229 drain_local_pages(NULL);
1230 copy_data_pages(©_bm, &orig_bm);
1233 * End of critical section. From now on, we can write to memory,
1234 * but we should not touch disk. This specially means we must _not_
1235 * touch swap space! Except we must write out our image of course.
1238 nr_pages += nr_highmem;
1239 nr_copy_pages = nr_pages;
1240 nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
1242 printk(KERN_INFO "PM: Hibernation image created (%d pages copied)\n",
1248 #ifndef CONFIG_ARCH_HIBERNATION_HEADER
1249 static int init_header_complete(struct swsusp_info *info)
1251 memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
1252 info->version_code = LINUX_VERSION_CODE;
1256 static char *check_image_kernel(struct swsusp_info *info)
1258 if (info->version_code != LINUX_VERSION_CODE)
1259 return "kernel version";
1260 if (strcmp(info->uts.sysname,init_utsname()->sysname))
1261 return "system type";
1262 if (strcmp(info->uts.release,init_utsname()->release))
1263 return "kernel release";
1264 if (strcmp(info->uts.version,init_utsname()->version))
1266 if (strcmp(info->uts.machine,init_utsname()->machine))
1270 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */
1272 unsigned long snapshot_get_image_size(void)
1274 return nr_copy_pages + nr_meta_pages + 1;
1277 static int init_header(struct swsusp_info *info)
1279 memset(info, 0, sizeof(struct swsusp_info));
1280 info->num_physpages = num_physpages;
1281 info->image_pages = nr_copy_pages;
1282 info->pages = snapshot_get_image_size();
1283 info->size = info->pages;
1284 info->size <<= PAGE_SHIFT;
1285 return init_header_complete(info);
1289 * pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
1290 * are stored in the array @buf[] (1 page at a time)
1294 pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
1298 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1299 buf[j] = memory_bm_next_pfn(bm);
1300 if (unlikely(buf[j] == BM_END_OF_MAP))
1306 * snapshot_read_next - used for reading the system memory snapshot.
1308 * On the first call to it @handle should point to a zeroed
1309 * snapshot_handle structure. The structure gets updated and a pointer
1310 * to it should be passed to this function every next time.
1312 * The @count parameter should contain the number of bytes the caller
1313 * wants to read from the snapshot. It must not be zero.
1315 * On success the function returns a positive number. Then, the caller
1316 * is allowed to read up to the returned number of bytes from the memory
1317 * location computed by the data_of() macro. The number returned
1318 * may be smaller than @count, but this only happens if the read would
1319 * cross a page boundary otherwise.
1321 * The function returns 0 to indicate the end of data stream condition,
1322 * and a negative number is returned on error. In such cases the
1323 * structure pointed to by @handle is not updated and should not be used
1327 int snapshot_read_next(struct snapshot_handle *handle, size_t count)
1329 if (handle->cur > nr_meta_pages + nr_copy_pages)
1333 /* This makes the buffer be freed by swsusp_free() */
1334 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
1338 if (!handle->offset) {
1341 error = init_header((struct swsusp_info *)buffer);
1344 handle->buffer = buffer;
1345 memory_bm_position_reset(&orig_bm);
1346 memory_bm_position_reset(©_bm);
1348 if (handle->prev < handle->cur) {
1349 if (handle->cur <= nr_meta_pages) {
1350 memset(buffer, 0, PAGE_SIZE);
1351 pack_pfns(buffer, &orig_bm);
1355 page = pfn_to_page(memory_bm_next_pfn(©_bm));
1356 if (PageHighMem(page)) {
1357 /* Highmem pages are copied to the buffer,
1358 * because we can't return with a kmapped
1359 * highmem page (we may not be called again).
1363 kaddr = kmap_atomic(page, KM_USER0);
1364 memcpy(buffer, kaddr, PAGE_SIZE);
1365 kunmap_atomic(kaddr, KM_USER0);
1366 handle->buffer = buffer;
1368 handle->buffer = page_address(page);
1371 handle->prev = handle->cur;
1373 handle->buf_offset = handle->cur_offset;
1374 if (handle->cur_offset + count >= PAGE_SIZE) {
1375 count = PAGE_SIZE - handle->cur_offset;
1376 handle->cur_offset = 0;
1379 handle->cur_offset += count;
1381 handle->offset += count;
1386 * mark_unsafe_pages - mark the pages that cannot be used for storing
1387 * the image during resume, because they conflict with the pages that
1388 * had been used before suspend
1391 static int mark_unsafe_pages(struct memory_bitmap *bm)
1394 unsigned long pfn, max_zone_pfn;
1396 /* Clear page flags */
1397 for_each_zone(zone) {
1398 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1399 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1401 swsusp_unset_page_free(pfn_to_page(pfn));
1404 /* Mark pages that correspond to the "original" pfns as "unsafe" */
1405 memory_bm_position_reset(bm);
1407 pfn = memory_bm_next_pfn(bm);
1408 if (likely(pfn != BM_END_OF_MAP)) {
1409 if (likely(pfn_valid(pfn)))
1410 swsusp_set_page_free(pfn_to_page(pfn));
1414 } while (pfn != BM_END_OF_MAP);
1416 allocated_unsafe_pages = 0;
1422 duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
1426 memory_bm_position_reset(src);
1427 pfn = memory_bm_next_pfn(src);
1428 while (pfn != BM_END_OF_MAP) {
1429 memory_bm_set_bit(dst, pfn);
1430 pfn = memory_bm_next_pfn(src);
1434 static int check_header(struct swsusp_info *info)
1438 reason = check_image_kernel(info);
1439 if (!reason && info->num_physpages != num_physpages)
1440 reason = "memory size";
1442 printk(KERN_ERR "PM: Image mismatch: %s\n", reason);
1449 * load header - check the image header and copy data from it
1453 load_header(struct swsusp_info *info)
1457 restore_pblist = NULL;
1458 error = check_header(info);
1460 nr_copy_pages = info->image_pages;
1461 nr_meta_pages = info->pages - info->image_pages - 1;
1467 * unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
1468 * the corresponding bit in the memory bitmap @bm
1470 static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
1474 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1475 if (unlikely(buf[j] == BM_END_OF_MAP))
1478 if (memory_bm_pfn_present(bm, buf[j]))
1479 memory_bm_set_bit(bm, buf[j]);
1487 /* List of "safe" pages that may be used to store data loaded from the suspend
1490 static struct linked_page *safe_pages_list;
1492 #ifdef CONFIG_HIGHMEM
1493 /* struct highmem_pbe is used for creating the list of highmem pages that
1494 * should be restored atomically during the resume from disk, because the page
1495 * frames they have occupied before the suspend are in use.
1497 struct highmem_pbe {
1498 struct page *copy_page; /* data is here now */
1499 struct page *orig_page; /* data was here before the suspend */
1500 struct highmem_pbe *next;
1503 /* List of highmem PBEs needed for restoring the highmem pages that were
1504 * allocated before the suspend and included in the suspend image, but have
1505 * also been allocated by the "resume" kernel, so their contents cannot be
1506 * written directly to their "original" page frames.
1508 static struct highmem_pbe *highmem_pblist;
1511 * count_highmem_image_pages - compute the number of highmem pages in the
1512 * suspend image. The bits in the memory bitmap @bm that correspond to the
1513 * image pages are assumed to be set.
1516 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
1519 unsigned int cnt = 0;
1521 memory_bm_position_reset(bm);
1522 pfn = memory_bm_next_pfn(bm);
1523 while (pfn != BM_END_OF_MAP) {
1524 if (PageHighMem(pfn_to_page(pfn)))
1527 pfn = memory_bm_next_pfn(bm);
1533 * prepare_highmem_image - try to allocate as many highmem pages as
1534 * there are highmem image pages (@nr_highmem_p points to the variable
1535 * containing the number of highmem image pages). The pages that are
1536 * "safe" (ie. will not be overwritten when the suspend image is
1537 * restored) have the corresponding bits set in @bm (it must be
1540 * NOTE: This function should not be called if there are no highmem
1544 static unsigned int safe_highmem_pages;
1546 static struct memory_bitmap *safe_highmem_bm;
1549 prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
1551 unsigned int to_alloc;
1553 if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
1556 if (get_highmem_buffer(PG_SAFE))
1559 to_alloc = count_free_highmem_pages();
1560 if (to_alloc > *nr_highmem_p)
1561 to_alloc = *nr_highmem_p;
1563 *nr_highmem_p = to_alloc;
1565 safe_highmem_pages = 0;
1566 while (to_alloc-- > 0) {
1569 page = alloc_page(__GFP_HIGHMEM);
1570 if (!swsusp_page_is_free(page)) {
1571 /* The page is "safe", set its bit the bitmap */
1572 memory_bm_set_bit(bm, page_to_pfn(page));
1573 safe_highmem_pages++;
1575 /* Mark the page as allocated */
1576 swsusp_set_page_forbidden(page);
1577 swsusp_set_page_free(page);
1579 memory_bm_position_reset(bm);
1580 safe_highmem_bm = bm;
1585 * get_highmem_page_buffer - for given highmem image page find the buffer
1586 * that suspend_write_next() should set for its caller to write to.
1588 * If the page is to be saved to its "original" page frame or a copy of
1589 * the page is to be made in the highmem, @buffer is returned. Otherwise,
1590 * the copy of the page is to be made in normal memory, so the address of
1591 * the copy is returned.
1593 * If @buffer is returned, the caller of suspend_write_next() will write
1594 * the page's contents to @buffer, so they will have to be copied to the
1595 * right location on the next call to suspend_write_next() and it is done
1596 * with the help of copy_last_highmem_page(). For this purpose, if
1597 * @buffer is returned, @last_highmem page is set to the page to which
1598 * the data will have to be copied from @buffer.
1601 static struct page *last_highmem_page;
1604 get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
1606 struct highmem_pbe *pbe;
1609 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
1610 /* We have allocated the "original" page frame and we can
1611 * use it directly to store the loaded page.
1613 last_highmem_page = page;
1616 /* The "original" page frame has not been allocated and we have to
1617 * use a "safe" page frame to store the loaded page.
1619 pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
1622 return ERR_PTR(-ENOMEM);
1624 pbe->orig_page = page;
1625 if (safe_highmem_pages > 0) {
1628 /* Copy of the page will be stored in high memory */
1630 tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
1631 safe_highmem_pages--;
1632 last_highmem_page = tmp;
1633 pbe->copy_page = tmp;
1635 /* Copy of the page will be stored in normal memory */
1636 kaddr = safe_pages_list;
1637 safe_pages_list = safe_pages_list->next;
1638 pbe->copy_page = virt_to_page(kaddr);
1640 pbe->next = highmem_pblist;
1641 highmem_pblist = pbe;
1646 * copy_last_highmem_page - copy the contents of a highmem image from
1647 * @buffer, where the caller of snapshot_write_next() has place them,
1648 * to the right location represented by @last_highmem_page .
1651 static void copy_last_highmem_page(void)
1653 if (last_highmem_page) {
1656 dst = kmap_atomic(last_highmem_page, KM_USER0);
1657 memcpy(dst, buffer, PAGE_SIZE);
1658 kunmap_atomic(dst, KM_USER0);
1659 last_highmem_page = NULL;
1663 static inline int last_highmem_page_copied(void)
1665 return !last_highmem_page;
1668 static inline void free_highmem_data(void)
1670 if (safe_highmem_bm)
1671 memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
1674 free_image_page(buffer, PG_UNSAFE_CLEAR);
1677 static inline int get_safe_write_buffer(void) { return 0; }
1680 count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
1683 prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
1688 static inline void *
1689 get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
1691 return ERR_PTR(-EINVAL);
1694 static inline void copy_last_highmem_page(void) {}
1695 static inline int last_highmem_page_copied(void) { return 1; }
1696 static inline void free_highmem_data(void) {}
1697 #endif /* CONFIG_HIGHMEM */
1700 * prepare_image - use the memory bitmap @bm to mark the pages that will
1701 * be overwritten in the process of restoring the system memory state
1702 * from the suspend image ("unsafe" pages) and allocate memory for the
1705 * The idea is to allocate a new memory bitmap first and then allocate
1706 * as many pages as needed for the image data, but not to assign these
1707 * pages to specific tasks initially. Instead, we just mark them as
1708 * allocated and create a lists of "safe" pages that will be used
1709 * later. On systems with high memory a list of "safe" highmem pages is
1713 #define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
1716 prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
1718 unsigned int nr_pages, nr_highmem;
1719 struct linked_page *sp_list, *lp;
1722 /* If there is no highmem, the buffer will not be necessary */
1723 free_image_page(buffer, PG_UNSAFE_CLEAR);
1726 nr_highmem = count_highmem_image_pages(bm);
1727 error = mark_unsafe_pages(bm);
1731 error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
1735 duplicate_memory_bitmap(new_bm, bm);
1736 memory_bm_free(bm, PG_UNSAFE_KEEP);
1737 if (nr_highmem > 0) {
1738 error = prepare_highmem_image(bm, &nr_highmem);
1742 /* Reserve some safe pages for potential later use.
1744 * NOTE: This way we make sure there will be enough safe pages for the
1745 * chain_alloc() in get_buffer(). It is a bit wasteful, but
1746 * nr_copy_pages cannot be greater than 50% of the memory anyway.
1749 /* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
1750 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
1751 nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
1752 while (nr_pages > 0) {
1753 lp = get_image_page(GFP_ATOMIC, PG_SAFE);
1762 /* Preallocate memory for the image */
1763 safe_pages_list = NULL;
1764 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
1765 while (nr_pages > 0) {
1766 lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
1771 if (!swsusp_page_is_free(virt_to_page(lp))) {
1772 /* The page is "safe", add it to the list */
1773 lp->next = safe_pages_list;
1774 safe_pages_list = lp;
1776 /* Mark the page as allocated */
1777 swsusp_set_page_forbidden(virt_to_page(lp));
1778 swsusp_set_page_free(virt_to_page(lp));
1781 /* Free the reserved safe pages so that chain_alloc() can use them */
1784 free_image_page(sp_list, PG_UNSAFE_CLEAR);
1795 * get_buffer - compute the address that snapshot_write_next() should
1796 * set for its caller to write to.
1799 static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
1803 unsigned long pfn = memory_bm_next_pfn(bm);
1805 if (pfn == BM_END_OF_MAP)
1806 return ERR_PTR(-EFAULT);
1808 page = pfn_to_page(pfn);
1809 if (PageHighMem(page))
1810 return get_highmem_page_buffer(page, ca);
1812 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
1813 /* We have allocated the "original" page frame and we can
1814 * use it directly to store the loaded page.
1816 return page_address(page);
1818 /* The "original" page frame has not been allocated and we have to
1819 * use a "safe" page frame to store the loaded page.
1821 pbe = chain_alloc(ca, sizeof(struct pbe));
1824 return ERR_PTR(-ENOMEM);
1826 pbe->orig_address = page_address(page);
1827 pbe->address = safe_pages_list;
1828 safe_pages_list = safe_pages_list->next;
1829 pbe->next = restore_pblist;
1830 restore_pblist = pbe;
1831 return pbe->address;
1835 * snapshot_write_next - used for writing the system memory snapshot.
1837 * On the first call to it @handle should point to a zeroed
1838 * snapshot_handle structure. The structure gets updated and a pointer
1839 * to it should be passed to this function every next time.
1841 * The @count parameter should contain the number of bytes the caller
1842 * wants to write to the image. It must not be zero.
1844 * On success the function returns a positive number. Then, the caller
1845 * is allowed to write up to the returned number of bytes to the memory
1846 * location computed by the data_of() macro. The number returned
1847 * may be smaller than @count, but this only happens if the write would
1848 * cross a page boundary otherwise.
1850 * The function returns 0 to indicate the "end of file" condition,
1851 * and a negative number is returned on error. In such cases the
1852 * structure pointed to by @handle is not updated and should not be used
1856 int snapshot_write_next(struct snapshot_handle *handle, size_t count)
1858 static struct chain_allocator ca;
1861 /* Check if we have already loaded the entire image */
1862 if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages)
1865 if (handle->offset == 0) {
1867 /* This makes the buffer be freed by swsusp_free() */
1868 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
1873 handle->buffer = buffer;
1875 handle->sync_read = 1;
1876 if (handle->prev < handle->cur) {
1877 if (handle->prev == 0) {
1878 error = load_header(buffer);
1882 error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
1886 } else if (handle->prev <= nr_meta_pages) {
1887 error = unpack_orig_pfns(buffer, ©_bm);
1891 if (handle->prev == nr_meta_pages) {
1892 error = prepare_image(&orig_bm, ©_bm);
1896 chain_init(&ca, GFP_ATOMIC, PG_SAFE);
1897 memory_bm_position_reset(&orig_bm);
1898 restore_pblist = NULL;
1899 handle->buffer = get_buffer(&orig_bm, &ca);
1900 handle->sync_read = 0;
1901 if (IS_ERR(handle->buffer))
1902 return PTR_ERR(handle->buffer);
1905 copy_last_highmem_page();
1906 handle->buffer = get_buffer(&orig_bm, &ca);
1907 if (IS_ERR(handle->buffer))
1908 return PTR_ERR(handle->buffer);
1909 if (handle->buffer != buffer)
1910 handle->sync_read = 0;
1912 handle->prev = handle->cur;
1914 handle->buf_offset = handle->cur_offset;
1915 if (handle->cur_offset + count >= PAGE_SIZE) {
1916 count = PAGE_SIZE - handle->cur_offset;
1917 handle->cur_offset = 0;
1920 handle->cur_offset += count;
1922 handle->offset += count;
1927 * snapshot_write_finalize - must be called after the last call to
1928 * snapshot_write_next() in case the last page in the image happens
1929 * to be a highmem page and its contents should be stored in the
1930 * highmem. Additionally, it releases the memory that will not be
1934 void snapshot_write_finalize(struct snapshot_handle *handle)
1936 copy_last_highmem_page();
1937 /* Free only if we have loaded the image entirely */
1938 if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages) {
1939 memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
1940 free_highmem_data();
1944 int snapshot_image_loaded(struct snapshot_handle *handle)
1946 return !(!nr_copy_pages || !last_highmem_page_copied() ||
1947 handle->cur <= nr_meta_pages + nr_copy_pages);
1950 #ifdef CONFIG_HIGHMEM
1951 /* Assumes that @buf is ready and points to a "safe" page */
1953 swap_two_pages_data(struct page *p1, struct page *p2, void *buf)
1955 void *kaddr1, *kaddr2;
1957 kaddr1 = kmap_atomic(p1, KM_USER0);
1958 kaddr2 = kmap_atomic(p2, KM_USER1);
1959 memcpy(buf, kaddr1, PAGE_SIZE);
1960 memcpy(kaddr1, kaddr2, PAGE_SIZE);
1961 memcpy(kaddr2, buf, PAGE_SIZE);
1962 kunmap_atomic(kaddr1, KM_USER0);
1963 kunmap_atomic(kaddr2, KM_USER1);
1967 * restore_highmem - for each highmem page that was allocated before
1968 * the suspend and included in the suspend image, and also has been
1969 * allocated by the "resume" kernel swap its current (ie. "before
1970 * resume") contents with the previous (ie. "before suspend") one.
1972 * If the resume eventually fails, we can call this function once
1973 * again and restore the "before resume" highmem state.
1976 int restore_highmem(void)
1978 struct highmem_pbe *pbe = highmem_pblist;
1984 buf = get_image_page(GFP_ATOMIC, PG_SAFE);
1989 swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
1992 free_image_page(buf, PG_UNSAFE_CLEAR);
1995 #endif /* CONFIG_HIGHMEM */