/* * linux/kernel/power/snapshot.c * * This file provides system snapshot/restore functionality for swsusp. * * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz> * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> * * This file is released under the GPLv2. * */ #include <linux/version.h> #include <linux/module.h> #include <linux/mm.h> #include <linux/suspend.h> #include <linux/delay.h> #include <linux/bitops.h> #include <linux/spinlock.h> #include <linux/kernel.h> #include <linux/pm.h> #include <linux/device.h> #include <linux/init.h> #include <linux/bootmem.h> #include <linux/syscalls.h> #include <linux/console.h> #include <linux/highmem.h> #include <linux/list.h> #include <linux/slab.h> #include <asm/uaccess.h> #include <asm/mmu_context.h> #include <asm/pgtable.h> #include <asm/tlbflush.h> #include <asm/io.h> #include "power.h" static int swsusp_page_is_free(struct page *); static void swsusp_set_page_forbidden(struct page *); static void swsusp_unset_page_forbidden(struct page *); /* * Number of bytes to reserve for memory allocations made by device drivers * from their ->freeze() and ->freeze_noirq() callbacks so that they don't * cause image creation to fail (tunable via /sys/power/reserved_size). */ unsigned long reserved_size; void __init hibernate_reserved_size_init(void) { reserved_size = SPARE_PAGES * PAGE_SIZE; } /* * Preferred image size in bytes (tunable via /sys/power/image_size). * When it is set to N, swsusp will do its best to ensure the image * size will not exceed N bytes, but if that is impossible, it will * try to create the smallest image possible. */ unsigned long image_size; void __init hibernate_image_size_init(void) { image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE; } /* List of PBEs needed for restoring the pages that were allocated before * the suspend and included in the suspend image, but have also been * allocated by the "resume" kernel, so their contents cannot be written * directly to their "original" page frames. */ struct pbe *restore_pblist; /* Pointer to an auxiliary buffer (1 page) */ static void *buffer; /** * @safe_needed - on resume, for storing the PBE list and the image, * we can only use memory pages that do not conflict with the pages * used before suspend. The unsafe pages have PageNosaveFree set * and we count them using unsafe_pages. * * Each allocated image page is marked as PageNosave and PageNosaveFree * so that swsusp_free() can release it. */ #define PG_ANY 0 #define PG_SAFE 1 #define PG_UNSAFE_CLEAR 1 #define PG_UNSAFE_KEEP 0 static unsigned int allocated_unsafe_pages; static void *get_image_page(gfp_t gfp_mask, int safe_needed) { void *res; res = (void *)get_zeroed_page(gfp_mask); if (safe_needed) while (res && swsusp_page_is_free(virt_to_page(res))) { /* The page is unsafe, mark it for swsusp_free() */ swsusp_set_page_forbidden(virt_to_page(res)); allocated_unsafe_pages++; res = (void *)get_zeroed_page(gfp_mask); } if (res) { swsusp_set_page_forbidden(virt_to_page(res)); swsusp_set_page_free(virt_to_page(res)); } return res; } unsigned long get_safe_page(gfp_t gfp_mask) { return (unsigned long)get_image_page(gfp_mask, PG_SAFE); } static struct page *alloc_image_page(gfp_t gfp_mask) { struct page *page; page = alloc_page(gfp_mask); if (page) { swsusp_set_page_forbidden(page); swsusp_set_page_free(page); } return page; } /** * free_image_page - free page represented by @addr, allocated with * get_image_page (page flags set by it must be cleared) */ static inline void free_image_page(void *addr, int clear_nosave_free) { struct page *page; BUG_ON(!virt_addr_valid(addr)); page = virt_to_page(addr); swsusp_unset_page_forbidden(page); if (clear_nosave_free) swsusp_unset_page_free(page); __free_page(page); } /* struct linked_page is used to build chains of pages */ #define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *)) struct linked_page { struct linked_page *next; char data[LINKED_PAGE_DATA_SIZE]; } __attribute__((packed)); static inline void free_list_of_pages(struct linked_page *list, int clear_page_nosave) { while (list) { struct linked_page *lp = list->next; free_image_page(list, clear_page_nosave); list = lp; } } /** * struct chain_allocator is used for allocating small objects out of * a linked list of pages called 'the chain'. * * The chain grows each time when there is no room for a new object in * the current page. The allocated objects cannot be freed individually. * It is only possible to free them all at once, by freeing the entire * chain. * * NOTE: The chain allocator may be inefficient if the allocated objects * are not much smaller than PAGE_SIZE. */ struct chain_allocator { struct linked_page *chain; /* the chain */ unsigned int used_space; /* total size of objects allocated out * of the current page */ gfp_t gfp_mask; /* mask for allocating pages */ int safe_needed; /* if set, only "safe" pages are allocated */ }; static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed) { ca->chain = NULL; ca->used_space = LINKED_PAGE_DATA_SIZE; ca->gfp_mask = gfp_mask; ca->safe_needed = safe_needed; } static void *chain_alloc(struct chain_allocator *ca, unsigned int size) { void *ret; if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) { struct linked_page *lp; lp = get_image_page(ca->gfp_mask, ca->safe_needed); if (!lp) return NULL; lp->next = ca->chain; ca->chain = lp; ca->used_space = 0; } ret = ca->chain->data + ca->used_space; ca->used_space += size; return ret; } /** * Data types related to memory bitmaps. * * Memory bitmap is a structure consiting of many linked lists of * objects. The main list's elements are of type struct zone_bitmap * and each of them corresonds to one zone. For each zone bitmap * object there is a list of objects of type struct bm_block that * represent each blocks of bitmap in which information is stored. * * struct memory_bitmap contains a pointer to the main list of zone * bitmap objects, a struct bm_position used for browsing the bitmap, * and a pointer to the list of pages used for allocating all of the * zone bitmap objects and bitmap block objects. * * NOTE: It has to be possible to lay out the bitmap in memory * using only allocations of order 0. Additionally, the bitmap is * designed to work with arbitrary number of zones (this is over the * top for now, but let's avoid making unnecessary assumptions ;-). * * struct zone_bitmap contains a pointer to a list of bitmap block * objects and a pointer to the bitmap block object that has been * most recently used for setting bits. Additionally, it contains the * pfns that correspond to the start and end of the represented zone. * * struct bm_block contains a pointer to the memory page in which * information is stored (in the form of a block of bitmap) * It also contains the pfns that correspond to the start and end of * the represented memory area. */ #define BM_END_OF_MAP (~0UL) #define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE) struct bm_block { struct list_head hook; /* hook into a list of bitmap blocks */ unsigned long start_pfn; /* pfn represented by the first bit */ unsigned long end_pfn; /* pfn represented by the last bit plus 1 */ unsigned long *data; /* bitmap representing pages */ }; static inline unsigned long bm_block_bits(struct bm_block *bb) { return bb->end_pfn - bb->start_pfn; } /* strcut bm_position is used for browsing memory bitmaps */ struct bm_position { struct bm_block *block; int bit; }; struct memory_bitmap { struct list_head blocks; /* list of bitmap blocks */ struct linked_page *p_list; /* list of pages used to store zone * bitmap objects and bitmap block * objects */ struct bm_position cur; /* most recently used bit position */ }; /* Functions that operate on memory bitmaps */ static void memory_bm_position_reset(struct memory_bitmap *bm) { bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook); bm->cur.bit = 0; } static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free); /** * create_bm_block_list - create a list of block bitmap objects * @pages - number of pages to track * @list - list to put the allocated blocks into * @ca - chain allocator to be used for allocating memory */ static int create_bm_block_list(unsigned long pages, struct list_head *list, struct chain_allocator *ca) { unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK); while (nr_blocks-- > 0) { struct bm_block *bb; bb = chain_alloc(ca, sizeof(struct bm_block)); if (!bb) return -ENOMEM; list_add(&bb->hook, list); } return 0; } struct mem_extent { struct list_head hook; unsigned long start; unsigned long end; }; /** * free_mem_extents - free a list of memory extents * @list - list of extents to empty */ static void free_mem_extents(struct list_head *list) { struct mem_extent *ext, *aux; list_for_each_entry_safe(ext, aux, list, hook) { list_del(&ext->hook); kfree(ext); } } /** * create_mem_extents - create a list of memory extents representing * contiguous ranges of PFNs * @list - list to put the extents into * @gfp_mask - mask to use for memory allocations */ static int create_mem_extents(struct list_head *list, gfp_t gfp_mask) { struct zone *zone; INIT_LIST_HEAD(list); for_each_populated_zone(zone) { unsigned long zone_start, zone_end; struct mem_extent *ext, *cur, *aux; zone_start = zone->zone_start_pfn; zone_end = zone->zone_start_pfn + zone->spanned_pages; list_for_each_entry(ext, list, hook) if (zone_start <= ext->end) break; if (&ext->hook == list || zone_end < ext->start) { /* New extent is necessary */ struct mem_extent *new_ext; new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask); if (!new_ext) { free_mem_extents(list); return -ENOMEM; } new_ext->start = zone_start; new_ext->end = zone_end; list_add_tail(&new_ext->hook, &ext->hook); continue; } /* Merge this zone's range of PFNs with the existing one */ if (zone_start < ext->start) ext->start = zone_start; if (zone_end > ext->end) ext->end = zone_end; /* More merging may be possible */ cur = ext; list_for_each_entry_safe_continue(cur, aux, list, hook) { if (zone_end < cur->start) break; if (zone_end < cur->end) ext->end = cur->end; list_del(&cur->hook); kfree(cur); } } return 0; } /** * memory_bm_create - allocate memory for a memory bitmap */ static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed) { struct chain_allocator ca; struct list_head mem_extents; struct mem_extent *ext; int error; chain_init(&ca, gfp_mask, safe_needed); INIT_LIST_HEAD(&bm->blocks); error = create_mem_extents(&mem_extents, gfp_mask); if (error) return error; list_for_each_entry(ext, &mem_extents, hook) { struct bm_block *bb; unsigned long pfn = ext->start; unsigned long pages = ext->end - ext->start; bb = list_entry(bm->blocks.prev, struct bm_block, hook); error = create_bm_block_list(pages, bm->blocks.prev, &ca); if (error) goto Error; list_for_each_entry_continue(bb, &bm->blocks, hook) { bb->data = get_image_page(gfp_mask, safe_needed); if (!bb->data) { error = -ENOMEM; goto Error; } bb->start_pfn = pfn; if (pages >= BM_BITS_PER_BLOCK) { pfn += BM_BITS_PER_BLOCK; pages -= BM_BITS_PER_BLOCK; } else { /* This is executed only once in the loop */ pfn += pages; } bb->end_pfn = pfn; } } bm->p_list = ca.chain; memory_bm_position_reset(bm); Exit: free_mem_extents(&mem_extents); return error; Error: bm->p_list = ca.chain; memory_bm_free(bm, PG_UNSAFE_CLEAR); goto Exit; } /** * memory_bm_free - free memory occupied by the memory bitmap @bm */ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free) { struct bm_block *bb; list_for_each_entry(bb, &bm->blocks, hook) if (bb->data) free_image_page(bb->data, clear_nosave_free); free_list_of_pages(bm->p_list, clear_nosave_free); INIT_LIST_HEAD(&bm->blocks); } /** * memory_bm_find_bit - find the bit in the bitmap @bm that corresponds * to given pfn. The cur_zone_bm member of @bm and the cur_block member * of @bm->cur_zone_bm are updated. */ static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, void **addr, unsigned int *bit_nr) { struct bm_block *bb; /* * Check if the pfn corresponds to the current bitmap block and find * the block where it fits if this is not the case. */ bb = bm->cur.block; if (pfn < bb->start_pfn) list_for_each_entry_continue_reverse(bb, &bm->blocks, hook) if (pfn >= bb->start_pfn) break; if (pfn >= bb->end_pfn) list_for_each_entry_continue(bb, &bm->blocks, hook) if (pfn >= bb->start_pfn && pfn < bb->end_pfn) break; if (&bb->hook == &bm->blocks) return -EFAULT; /* The block has been found */ bm->cur.block = bb; pfn -= bb->start_pfn; bm->cur.bit = pfn + 1; *bit_nr = pfn; *addr = bb->data; return 0; } static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn) { void *addr; unsigned int bit; int error; error = memory_bm_find_bit(bm, pfn, &addr, &bit); BUG_ON(error); set_bit(bit, addr); } static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn) { void *addr; unsigned int bit; int error; error = memory_bm_find_bit(bm, pfn, &addr, &bit); if (!error) set_bit(bit, addr); return error; } static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn) { void *addr; unsigned int bit; int error; error = memory_bm_find_bit(bm, pfn, &addr, &bit); BUG_ON(error); clear_bit(bit, addr); } static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn) { void *addr; unsigned int bit; int error; error = memory_bm_find_bit(bm, pfn, &addr, &bit); BUG_ON(error); return test_bit(bit, addr); } static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn) { void *addr; unsigned int bit; return !memory_bm_find_bit(bm, pfn, &addr, &bit); } /** * memory_bm_next_pfn - find the pfn that corresponds to the next set bit * in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is * returned. * * It is required to run memory_bm_position_reset() before the first call to * this function. */ static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm) { struct bm_block *bb; int bit; bb = bm->cur.block; do { bit = bm->cur.bit; bit = find_next_bit(bb->data, bm_block_bits(bb), bit); if (bit < bm_block_bits(bb)) goto Return_pfn; bb = list_entry(bb->hook.next, struct bm_block, hook); bm->cur.block = bb; bm->cur.bit = 0; } while (&bb->hook != &bm->blocks); memory_bm_position_reset(bm); return BM_END_OF_MAP; Return_pfn: bm->cur.bit = bit + 1; return bb->start_pfn + bit; } /** * This structure represents a range of page frames the contents of which * should not be saved during the suspend. */ struct nosave_region { struct list_head list; unsigned long start_pfn; unsigned long end_pfn; }; static LIST_HEAD(nosave_regions); /** * register_nosave_region - register a range of page frames the contents * of which should not be saved during the suspend (to be used in the early * initialization code) */ void __init __register_nosave_region(unsigned long start_pfn, unsigned long end_pfn, int use_kmalloc) { struct nosave_region *region; if (start_pfn >= end_pfn) return; if (!list_empty(&nosave_regions)) { /* Try to extend the previous region (they should be sorted) */ region = list_entry(nosave_regions.prev, struct nosave_region, list); if (region->end_pfn == start_pfn) { region->end_pfn = end_pfn; goto Report; } } if (use_kmalloc) { /* during init, this shouldn't fail */ region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL); BUG_ON(!region); } else /* This allocation cannot fail */ region = alloc_bootmem(sizeof(struct nosave_region)); region->start_pfn = start_pfn; region->end_pfn = end_pfn; list_add_tail(®ion->list, &nosave_regions); Report: printk(KERN_INFO "PM: Registered nosave memory: %016lx - %016lx\n", start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT); } /* * Set bits in this map correspond to the page frames the contents of which * should not be saved during the suspend. */ static struct memory_bitmap *forbidden_pages_map; /* Set bits in this map correspond to free page frames. */ static struct memory_bitmap *free_pages_map; /* * Each page frame allocated for creating the image is marked by setting the * corresponding bits in forbidden_pages_map and free_pages_map simultaneously */ void swsusp_set_page_free(struct page *page) { if (free_pages_map) memory_bm_set_bit(free_pages_map, page_to_pfn(page)); } static int swsusp_page_is_free(struct page *page) { return free_pages_map ? memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0; } void swsusp_unset_page_free(struct page *page) { if (free_pages_map) memory_bm_clear_bit(free_pages_map, page_to_pfn(page)); } static void swsusp_set_page_forbidden(struct page *page) { if (forbidden_pages_map) memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page)); } int swsusp_page_is_forbidden(struct page *page) { return forbidden_pages_map ? memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0; } static void swsusp_unset_page_forbidden(struct page *page) { if (forbidden_pages_map) memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page)); } /** * mark_nosave_pages - set bits corresponding to the page frames the * contents of which should not be saved in a given bitmap. */ static void mark_nosave_pages(struct memory_bitmap *bm) { struct nosave_region *region; if (list_empty(&nosave_regions)) return; list_for_each_entry(region, &nosave_regions, list) { unsigned long pfn; pr_debug("PM: Marking nosave pages: %016lx - %016lx\n", region->start_pfn << PAGE_SHIFT, region->end_pfn << PAGE_SHIFT); for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++) if (pfn_valid(pfn)) { /* * It is safe to ignore the result of * mem_bm_set_bit_check() here, since we won't * touch the PFNs for which the error is * returned anyway. */ mem_bm_set_bit_check(bm, pfn); } } } /** * create_basic_memory_bitmaps - create bitmaps needed for marking page * frames that should not be saved and free page frames. The pointers * forbidden_pages_map and free_pages_map are only modified if everything * goes well, because we don't want the bits to be used before both bitmaps * are set up. */ int create_basic_memory_bitmaps(void) { struct memory_bitmap *bm1, *bm2; int error = 0; BUG_ON(forbidden_pages_map || free_pages_map); bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL); if (!bm1) return -ENOMEM; error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY); if (error) goto Free_first_object; bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL); if (!bm2) goto Free_first_bitmap; error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY); if (error) goto Free_second_object; forbidden_pages_map = bm1; free_pages_map = bm2; mark_nosave_pages(forbidden_pages_map); pr_debug("PM: Basic memory bitmaps created\n"); return 0; Free_second_object: kfree(bm2); Free_first_bitmap: memory_bm_free(bm1, PG_UNSAFE_CLEAR); Free_first_object: kfree(bm1); return -ENOMEM; } /** * free_basic_memory_bitmaps - free memory bitmaps allocated by * create_basic_memory_bitmaps(). The auxiliary pointers are necessary * so that the bitmaps themselves are not referred to while they are being * freed. */ void free_basic_memory_bitmaps(void) { struct memory_bitmap *bm1, *bm2; BUG_ON(!(forbidden_pages_map && free_pages_map)); bm1 = forbidden_pages_map; bm2 = free_pages_map; forbidden_pages_map = NULL; free_pages_map = NULL; memory_bm_free(bm1, PG_UNSAFE_CLEAR); kfree(bm1); memory_bm_free(bm2, PG_UNSAFE_CLEAR); kfree(bm2); pr_debug("PM: Basic memory bitmaps freed\n"); } /** * snapshot_additional_pages - estimate the number of additional pages * be needed for setting up the suspend image data structures for given * zone (usually the returned value is greater than the exact number) */ unsigned int snapshot_additional_pages(struct zone *zone) { unsigned int res; res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK); res += DIV_ROUND_UP(res * sizeof(struct bm_block), PAGE_SIZE); return 2 * res; } #ifdef CONFIG_HIGHMEM /** * count_free_highmem_pages - compute the total number of free highmem * pages, system-wide. */ static unsigned int count_free_highmem_pages(void) { struct zone *zone; unsigned int cnt = 0; for_each_populated_zone(zone) if (is_highmem(zone)) cnt += zone_page_state(zone, NR_FREE_PAGES); return cnt; } /** * saveable_highmem_page - Determine whether a highmem page should be * included in the suspend image. * * We should save the page if it isn't Nosave or NosaveFree, or Reserved, * and it isn't a part of a free chunk of pages. */ static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn) { struct page *page; if (!pfn_valid(pfn)) return NULL; page = pfn_to_page(pfn); if (page_zone(page) != zone) return NULL; BUG_ON(!PageHighMem(page)); if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page) || PageReserved(page)) return NULL; return page; } /** * count_highmem_pages - compute the total number of saveable highmem * pages. */ static unsigned int count_highmem_pages(void) { struct zone *zone; unsigned int n = 0; for_each_populated_zone(zone) { unsigned long pfn, max_zone_pfn; if (!is_highmem(zone)) continue; mark_free_pages(zone); max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages; for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) if (saveable_highmem_page(zone, pfn)) n++; } return n; } #else static inline void *saveable_highmem_page(struct zone *z, unsigned long p) { return NULL; } #endif /* CONFIG_HIGHMEM */ /** * saveable_page - Determine whether a non-highmem page should be included * in the suspend image. * * We should save the page if it isn't Nosave, and is not in the range * of pages statically defined as 'unsaveable', and it isn't a part of * a free chunk of pages. */ static struct page *saveable_page(struct zone *zone, unsigned long pfn) { struct page *page; if (!pfn_valid(pfn)) return NULL; page = pfn_to_page(pfn); if (page_zone(page) != zone) return NULL; BUG_ON(PageHighMem(page)); if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page)) return NULL; if (PageReserved(page) && (!kernel_page_present(page) || pfn_is_nosave(pfn))) return NULL; return page; } /** * count_data_pages - compute the total number of saveable non-highmem * pages. */ static unsigned int count_data_pages(void) { struct zone *zone; unsigned long pfn, max_zone_pfn; unsigned int n = 0; for_each_populated_zone(zone) { if (is_highmem(zone)) continue; mark_free_pages(zone); max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages; for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) if (saveable_page(zone, pfn)) n++; } return n; } /* This is needed, because copy_page and memcpy are not usable for copying * task structs. */ static inline void do_copy_page(long *dst, long *src) { int n; for (n = PAGE_SIZE / sizeof(long); n; n--) *dst++ = *src++; } /** * safe_copy_page - check if the page we are going to copy is marked as * present in the kernel page tables (this always is the case if * CONFIG_DEBUG_PAGEALLOC is not set and in that case * kernel_page_present() always returns 'true'). */ static void safe_copy_page(void *dst, struct page *s_page) { if (kernel_page_present(s_page)) { do_copy_page(dst, page_address(s_page)); } else { kernel_map_pages(s_page, 1, 1); do_copy_page(dst, page_address(s_page)); kernel_map_pages(s_page, 1, 0); } } #ifdef CONFIG_HIGHMEM static inline struct page * page_is_saveable(struct zone *zone, unsigned long pfn) { return is_highmem(zone) ? saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn); } static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn) { struct page *s_page, *d_page; void *src, *dst; s_page = pfn_to_page(src_pfn); d_page = pfn_to_page(dst_pfn); if (PageHighMem(s_page)) { src = kmap_atomic(s_page, KM_USER0); dst = kmap_atomic(d_page, KM_USER1); do_copy_page(dst, src); kunmap_atomic(dst, KM_USER1); kunmap_atomic(src, KM_USER0); } else { if (PageHighMem(d_page)) { /* Page pointed to by src may contain some kernel * data modified by kmap_atomic() */ safe_copy_page(buffer, s_page); dst = kmap_atomic(d_page, KM_USER0); copy_page(dst, buffer); kunmap_atomic(dst, KM_USER0); } else { safe_copy_page(page_address(d_page), s_page); } } } #else #define page_is_saveable(zone, pfn) saveable_page(zone, pfn) static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn) { safe_copy_page(page_address(pfn_to_page(dst_pfn)), pfn_to_page(src_pfn)); } #endif /* CONFIG_HIGHMEM */ static void copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm) { struct zone *zone; unsigned long pfn; for_each_populated_zone(zone) { unsigned long max_zone_pfn; mark_free_pages(zone); max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages; for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) if (page_is_saveable(zone, pfn)) memory_bm_set_bit(orig_bm, pfn); } memory_bm_position_reset(orig_bm); memory_bm_position_reset(copy_bm); for(;;) { pfn = memory_bm_next_pfn(orig_bm); if (unlikely(pfn == BM_END_OF_MAP)) break; copy_data_page(memory_bm_next_pfn(copy_bm), pfn); } } /* Total number of image pages */ static unsigned int nr_copy_pages; /* Number of pages needed for saving the original pfns of the image pages */ static unsigned int nr_meta_pages; /* * Numbers of normal and highmem page frames allocated for hibernation image * before suspending devices. */ unsigned int alloc_normal, alloc_highmem; /* * Memory bitmap used for marking saveable pages (during hibernation) or * hibernation image pages (during restore) */ static struct memory_bitmap orig_bm; /* * Memory bitmap used during hibernation for marking allocated page frames that * will contain copies of saveable pages. During restore it is initially used * for marking hibernation image pages, but then the set bits from it are * duplicated in @orig_bm and it is released. On highmem systems it is next * used for marking "safe" highmem pages, but it has to be reinitialized for * this purpose. */ static struct memory_bitmap copy_bm; /** * swsusp_free - free pages allocated for the suspend. * * Suspend pages are alocated before the atomic copy is made, so we * need to release them after the resume. */ void swsusp_free(void) { struct zone *zone; unsigned long pfn, max_zone_pfn; for_each_populated_zone(zone) { max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages; for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) if (pfn_valid(pfn)) { struct page *page = pfn_to_page(pfn); if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) { swsusp_unset_page_forbidden(page); swsusp_unset_page_free(page); __free_page(page); } } } nr_copy_pages = 0; nr_meta_pages = 0; restore_pblist = NULL; buffer = NULL; alloc_normal = 0; alloc_highmem = 0; } /* Helper functions used for the shrinking of memory. */ #define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN) /** * preallocate_image_pages - Allocate a number of pages for hibernation image * @nr_pages: Number of page frames to allocate. * @mask: GFP flags to use for the allocation. * * Return value: Number of page frames actually allocated */ static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask) { unsigned long nr_alloc = 0; while (nr_pages > 0) { struct page *page; page = alloc_image_page(mask); if (!page) break; memory_bm_set_bit(©_bm, page_to_pfn(page)); if (PageHighMem(page)) alloc_highmem++; else alloc_normal++; nr_pages--; nr_alloc++; } return nr_alloc; } static unsigned long preallocate_image_memory(unsigned long nr_pages, unsigned long avail_normal) { unsigned long alloc; if (avail_normal <= alloc_normal) return 0; alloc = avail_normal - alloc_normal; if (nr_pages < alloc) alloc = nr_pages; return preallocate_image_pages(alloc, GFP_IMAGE); } #ifdef CONFIG_HIGHMEM static unsigned long preallocate_image_highmem(unsigned long nr_pages) { return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM); } /** * __fraction - Compute (an approximation of) x * (multiplier / base) */ static unsigned long __fraction(u64 x, u64 multiplier, u64 base) { x *= multiplier; do_div(x, base); return (unsigned long)x; } static unsigned long preallocate_highmem_fraction(unsigned long nr_pages, unsigned long highmem, unsigned long total) { unsigned long alloc = __fraction(nr_pages, highmem, total); return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM); } #else /* CONFIG_HIGHMEM */ static inline unsigned long preallocate_image_highmem(unsigned long nr_pages) { return 0; } static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages, unsigned long highmem, unsigned long total) { return 0; } #endif /* CONFIG_HIGHMEM */ /** * free_unnecessary_pages - Release preallocated pages not needed for the image */ static void free_unnecessary_pages(void) { unsigned long save, to_free_normal, to_free_highmem; save = count_data_pages(); if (alloc_normal >= save) { to_free_normal = alloc_normal - save; save = 0; } else { to_free_normal = 0; save -= alloc_normal; } save += count_highmem_pages(); if (alloc_highmem >= save) { to_free_highmem = alloc_highmem - save; } else { to_free_highmem = 0; save -= alloc_highmem; if (to_free_normal > save) to_free_normal -= save; else to_free_normal = 0; } memory_bm_position_reset(©_bm); while (to_free_normal > 0 || to_free_highmem > 0) { unsigned long pfn = memory_bm_next_pfn(©_bm); struct page *page = pfn_to_page(pfn); if (PageHighMem(page)) { if (!to_free_highmem) continue; to_free_highmem--; alloc_highmem--; } else { if (!to_free_normal) continue; to_free_normal--; alloc_normal--; } memory_bm_clear_bit(©_bm, pfn); swsusp_unset_page_forbidden(page); swsusp_unset_page_free(page); __free_page(page); } } /** * minimum_image_size - Estimate the minimum acceptable size of an image * @saveable: Number of saveable pages in the system. * * We want to avoid attempting to free too much memory too hard, so estimate the * minimum acceptable size of a hibernation image to use as the lower limit for * preallocating memory. * * We assume that the minimum image size should be proportional to * * [number of saveable pages] - [number of pages that can be freed in theory] * * where the second term is the sum of (1) reclaimable slab pages, (2) active * and (3) inactive anonymouns pages, (4) active and (5) inactive file pages, * minus mapped file pages. */ static unsigned long minimum_image_size(unsigned long saveable) { unsigned long size; size = global_page_state(NR_SLAB_RECLAIMABLE) + global_page_state(NR_ACTIVE_ANON) + global_page_state(NR_INACTIVE_ANON) + global_page_state(NR_ACTIVE_FILE) + global_page_state(NR_INACTIVE_FILE) - global_page_state(NR_FILE_MAPPED); return saveable <= size ? 0 : saveable - size; } /** * hibernate_preallocate_memory - Preallocate memory for hibernation image * * To create a hibernation image it is necessary to make a copy of every page * frame in use. We also need a number of page frames to be free during * hibernation for allocations made while saving the image and for device * drivers, in case they need to allocate memory from their hibernation * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough * estimate) and reserverd_size divided by PAGE_SIZE (which is tunable through * /sys/power/reserved_size, respectively). To make this happen, we compute the * total number of available page frames and allocate at least * * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2 * + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE) * * of them, which corresponds to the maximum size of a hibernation image. * * If image_size is set below the number following from the above formula, * the preallocation of memory is continued until the total number of saveable * pages in the system is below the requested image size or the minimum * acceptable image size returned by minimum_image_size(), whichever is greater. */ int hibernate_preallocate_memory(void) { struct zone *zone; unsigned long saveable, size, max_size, count, highmem, pages = 0; unsigned long alloc, save_highmem, pages_highmem, avail_normal; struct timeval start, stop; int error; printk(KERN_INFO "PM: Preallocating image memory... "); do_gettimeofday(&start); error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY); if (error) goto err_out; error = memory_bm_create(©_bm, GFP_IMAGE, PG_ANY); if (error) goto err_out; alloc_normal = 0; alloc_highmem = 0; /* Count the number of saveable data pages. */ save_highmem = count_highmem_pages(); saveable = count_data_pages(); /* * Compute the total number of page frames we can use (count) and the * number of pages needed for image metadata (size). */ count = saveable; saveable += save_highmem; highmem = save_highmem; size = 0; for_each_populated_zone(zone) { size += snapshot_additional_pages(zone); if (is_highmem(zone)) highmem += zone_page_state(zone, NR_FREE_PAGES); else count += zone_page_state(zone, NR_FREE_PAGES); } avail_normal = count; count += highmem; count -= totalreserve_pages; /* Add number of pages required for page keys (s390 only). */ size += page_key_additional_pages(saveable); /* Compute the maximum number of saveable pages to leave in memory. */ max_size = (count - (size + PAGES_FOR_IO)) / 2 - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE); /* Compute the desired number of image pages specified by image_size. */ size = DIV_ROUND_UP(image_size, PAGE_SIZE); if (size > max_size) size = max_size; /* * If the desired number of image pages is at least as large as the * current number of saveable pages in memory, allocate page frames for * the image and we're done. */ if (size >= saveable) { pages = preallocate_image_highmem(save_highmem); pages += preallocate_image_memory(saveable - pages, avail_normal); goto out; } /* Estimate the minimum size of the image. */ pages = minimum_image_size(saveable); /* * To avoid excessive pressure on the normal zone, leave room in it to * accommodate an image of the minimum size (unless it's already too * small, in which case don't preallocate pages from it at all). */ if (avail_normal > pages) avail_normal -= pages; else avail_normal = 0; if (size < pages) size = min_t(unsigned long, pages, max_size); /* * Let the memory management subsystem know that we're going to need a * large number of page frames to allocate and make it free some memory. * NOTE: If this is not done, performance will be hurt badly in some * test cases. */ shrink_all_memory(saveable - size); /* * The number of saveable pages in memory was too high, so apply some * pressure to decrease it. First, make room for the largest possible * image and fail if that doesn't work. Next, try to decrease the size * of the image as much as indicated by 'size' using allocations from * highmem and non-highmem zones separately. */ pages_highmem = preallocate_image_highmem(highmem / 2); alloc = (count - max_size) - pages_highmem; pages = preallocate_image_memory(alloc, avail_normal); if (pages < alloc) { /* We have exhausted non-highmem pages, try highmem. */ alloc -= pages; pages += pages_highmem; pages_highmem = preallocate_image_highmem(alloc); if (pages_highmem < alloc) goto err_out; pages += pages_highmem; /* * size is the desired number of saveable pages to leave in * memory, so try to preallocate (all memory - size) pages. */ alloc = (count - pages) - size; pages += preallocate_image_highmem(alloc); } else { /* * There are approximately max_size saveable pages at this point * and we want to reduce this number down to size. */ alloc = max_size - size; size = preallocate_highmem_fraction(alloc, highmem, count); pages_highmem += size; alloc -= size; size = preallocate_image_memory(alloc, avail_normal); pages_highmem += preallocate_image_highmem(alloc - size); pages += pages_highmem + size; } /* * We only need as many page frames for the image as there are saveable * pages in memory, but we have allocated more. Release the excessive * ones now. */ free_unnecessary_pages(); out: do_gettimeofday(&stop); printk(KERN_CONT "done (allocated %lu pages)\n", pages); swsusp_show_speed(&start, &stop, pages, "Allocated"); return 0; err_out: printk(KERN_CONT "\n"); swsusp_free(); return -ENOMEM; } #ifdef CONFIG_HIGHMEM /** * count_pages_for_highmem - compute the number of non-highmem pages * that will be necessary for creating copies of highmem pages. */ static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem; if (free_highmem >= nr_highmem) nr_highmem = 0; else nr_highmem -= free_highmem; return nr_highmem; } #else static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; } #endif /* CONFIG_HIGHMEM */ /** * enough_free_mem - Make sure we have enough free memory for the * snapshot image. */ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) { struct zone *zone; unsigned int free = alloc_normal; for_each_populated_zone(zone) if (!is_highmem(zone)) free += zone_page_state(zone, NR_FREE_PAGES); nr_pages += count_pages_for_highmem(nr_highmem); pr_debug("PM: Normal pages needed: %u + %u, available pages: %u\n", nr_pages, PAGES_FOR_IO, free); return free > nr_pages + PAGES_FOR_IO; } #ifdef CONFIG_HIGHMEM /** * get_highmem_buffer - if there are some highmem pages in the suspend * image, we may need the buffer to copy them and/or load their data. */ static inline int get_highmem_buffer(int safe_needed) { buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed); return buffer ? 0 : -ENOMEM; } /** * alloc_highmem_image_pages - allocate some highmem pages for the image. * Try to allocate as many pages as needed, but if the number of free * highmem pages is lesser than that, allocate them all. */ static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, unsigned int nr_highmem) { unsigned int to_alloc = count_free_highmem_pages(); if (to_alloc > nr_highmem) to_alloc = nr_highmem; nr_highmem -= to_alloc; while (to_alloc-- > 0) { struct page *page; page = alloc_image_page(__GFP_HIGHMEM); memory_bm_set_bit(bm, page_to_pfn(page)); } return nr_highmem; } #else static inline int get_highmem_buffer(int safe_needed) { return 0; } static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, unsigned int n) { return 0; } #endif /* CONFIG_HIGHMEM */ /** * swsusp_alloc - allocate memory for the suspend image * * We first try to allocate as many highmem pages as there are * saveable highmem pages in the system. If that fails, we allocate * non-highmem pages for the copies of the remaining highmem ones. * * In this approach it is likely that the copies of highmem pages will * also be located in the high memory, because of the way in which * copy_data_pages() works. */ static int swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm, unsigned int nr_pages, unsigned int nr_highmem) { if (nr_highmem > 0) { if (get_highmem_buffer(PG_ANY)) goto err_out; if (nr_highmem > alloc_highmem) { nr_highmem -= alloc_highmem; nr_pages += alloc_highmem_pages(copy_bm, nr_highmem); } } if (nr_pages > alloc_normal) { nr_pages -= alloc_normal; while (nr_pages-- > 0) { struct page *page; page = alloc_image_page(GFP_ATOMIC | __GFP_COLD); if (!page) goto err_out; memory_bm_set_bit(copy_bm, page_to_pfn(page)); } } return 0; err_out: swsusp_free(); return -ENOMEM; } asmlinkage int swsusp_save(void) { unsigned int nr_pages, nr_highmem; printk(KERN_INFO "PM: Creating hibernation image:\n"); drain_local_pages(NULL); nr_pages = count_data_pages(); nr_highmem = count_highmem_pages(); printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem); if (!enough_free_mem(nr_pages, nr_highmem)) { printk(KERN_ERR "PM: Not enough free memory\n"); return -ENOMEM; } if (swsusp_alloc(&orig_bm, ©_bm, nr_pages, nr_highmem)) { printk(KERN_ERR "PM: Memory allocation failed\n"); return -ENOMEM; } /* During allocating of suspend pagedir, new cold pages may appear. * Kill them. */ drain_local_pages(NULL); copy_data_pages(©_bm, &orig_bm); /* * End of critical section. From now on, we can write to memory, * but we should not touch disk. This specially means we must _not_ * touch swap space! Except we must write out our image of course. */ nr_pages += nr_highmem; nr_copy_pages = nr_pages; nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE); printk(KERN_INFO "PM: Hibernation image created (%d pages copied)\n", nr_pages); return 0; } #ifndef CONFIG_ARCH_HIBERNATION_HEADER static int init_header_complete(struct swsusp_info *info) { memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname)); info->version_code = LINUX_VERSION_CODE; return 0; } static char *check_image_kernel(struct swsusp_info *info) { if (info->version_code != LINUX_VERSION_CODE) return "kernel version"; if (strcmp(info->uts.sysname,init_utsname()->sysname)) return "system type"; if (strcmp(info->uts.release,init_utsname()->release)) return "kernel release"; if (strcmp(info->uts.version,init_utsname()->version)) return "version"; if (strcmp(info->uts.machine,init_utsname()->machine)) return "machine"; return NULL; } #endif /* CONFIG_ARCH_HIBERNATION_HEADER */ unsigned long snapshot_get_image_size(void) { return nr_copy_pages + nr_meta_pages + 1; } static int init_header(struct swsusp_info *info) { memset(info, 0, sizeof(struct swsusp_info)); info->num_physpages = num_physpages; info->image_pages = nr_copy_pages; info->pages = snapshot_get_image_size(); info->size = info->pages; info->size <<= PAGE_SHIFT; return init_header_complete(info); } /** * pack_pfns - pfns corresponding to the set bits found in the bitmap @bm * are stored in the array @buf[] (1 page at a time) */ static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm) { int j; for (j = 0; j < PAGE_SIZE / sizeof(long); j++) { buf[j] = memory_bm_next_pfn(bm); if (unlikely(buf[j] == BM_END_OF_MAP)) break; /* Save page key for data page (s390 only). */ page_key_read(buf + j); } } /** * snapshot_read_next - used for reading the system memory snapshot. * * On the first call to it @handle should point to a zeroed * snapshot_handle structure. The structure gets updated and a pointer * to it should be passed to this function every next time. * * On success the function returns a positive number. Then, the caller * is allowed to read up to the returned number of bytes from the memory * location computed by the data_of() macro. * * The function returns 0 to indicate the end of data stream condition, * and a negative number is returned on error. In such cases the * structure pointed to by @handle is not updated and should not be used * any more. */ int snapshot_read_next(struct snapshot_handle *handle) { if (handle->cur > nr_meta_pages + nr_copy_pages) return 0; if (!buffer) { /* This makes the buffer be freed by swsusp_free() */ buffer = get_image_page(GFP_ATOMIC, PG_ANY); if (!buffer) return -ENOMEM; } if (!handle->cur) { int error; error = init_header((struct swsusp_info *)buffer); if (error) return error; handle->buffer = buffer; memory_bm_position_reset(&orig_bm); memory_bm_position_reset(©_bm); } else if (handle->cur <= nr_meta_pages) { clear_page(buffer); pack_pfns(buffer, &orig_bm); } else { struct page *page; page = pfn_to_page(memory_bm_next_pfn(©_bm)); if (PageHighMem(page)) { /* Highmem pages are copied to the buffer, * because we can't return with a kmapped * highmem page (we may not be called again). */ void *kaddr; kaddr = kmap_atomic(page, KM_USER0); copy_page(buffer, kaddr); kunmap_atomic(kaddr, KM_USER0); handle->buffer = buffer; } else { handle->buffer = page_address(page); } } handle->cur++; return PAGE_SIZE; } /** * mark_unsafe_pages - mark the pages that cannot be used for storing * the image during resume, because they conflict with the pages that * had been used before suspend */ static int mark_unsafe_pages(struct memory_bitmap *bm) { struct zone *zone; unsigned long pfn, max_zone_pfn; /* Clear page flags */ for_each_populated_zone(zone) { max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages; for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) if (pfn_valid(pfn)) swsusp_unset_page_free(pfn_to_page(pfn)); } /* Mark pages that correspond to the "original" pfns as "unsafe" */ memory_bm_position_reset(bm); do { pfn = memory_bm_next_pfn(bm); if (likely(pfn != BM_END_OF_MAP)) { if (likely(pfn_valid(pfn))) swsusp_set_page_free(pfn_to_page(pfn)); else return -EFAULT; } } while (pfn != BM_END_OF_MAP); allocated_unsafe_pages = 0; return 0; } static void duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src) { unsigned long pfn; memory_bm_position_reset(src); pfn = memory_bm_next_pfn(src); while (pfn != BM_END_OF_MAP) { memory_bm_set_bit(dst, pfn); pfn = memory_bm_next_pfn(src); } } static int check_header(struct swsusp_info *info) { char *reason; reason = check_image_kernel(info); if (!reason && info->num_physpages != num_physpages) reason = "memory size"; if (reason) { printk(KERN_ERR "PM: Image mismatch: %s\n", reason); return -EPERM; } return 0; } /** * load header - check the image header and copy data from it */ static int load_header(struct swsusp_info *info) { int error; restore_pblist = NULL; error = check_header(info); if (!error) { nr_copy_pages = info->image_pages; nr_meta_pages = info->pages - info->image_pages - 1; } return error; } /** * unpack_orig_pfns - for each element of @buf[] (1 page at a time) set * the corresponding bit in the memory bitmap @bm */ static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm) { int j; for (j = 0; j < PAGE_SIZE / sizeof(long); j++) { if (unlikely(buf[j] == BM_END_OF_MAP)) break; /* Extract and buffer page key for data page (s390 only). */ page_key_memorize(buf + j); if (memory_bm_pfn_present(bm, buf[j])) memory_bm_set_bit(bm, buf[j]); else return -EFAULT; } return 0; } /* List of "safe" pages that may be used to store data loaded from the suspend * image */ static struct linked_page *safe_pages_list; #ifdef CONFIG_HIGHMEM /* struct highmem_pbe is used for creating the list of highmem pages that * should be restored atomically during the resume from disk, because the page * frames they have occupied before the suspend are in use. */ struct highmem_pbe { struct page *copy_page; /* data is here now */ struct page *orig_page; /* data was here before the suspend */ struct highmem_pbe *next; }; /* List of highmem PBEs needed for restoring the highmem pages that were * allocated before the suspend and included in the suspend image, but have * also been allocated by the "resume" kernel, so their contents cannot be * written directly to their "original" page frames. */ static struct highmem_pbe *highmem_pblist; /** * count_highmem_image_pages - compute the number of highmem pages in the * suspend image. The bits in the memory bitmap @bm that correspond to the * image pages are assumed to be set. */ static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { unsigned long pfn; unsigned int cnt = 0; memory_bm_position_reset(bm); pfn = memory_bm_next_pfn(bm); while (pfn != BM_END_OF_MAP) { if (PageHighMem(pfn_to_page(pfn))) cnt++; pfn = memory_bm_next_pfn(bm); } return cnt; } /** * prepare_highmem_image - try to allocate as many highmem pages as * there are highmem image pages (@nr_highmem_p points to the variable * containing the number of highmem image pages). The pages that are * "safe" (ie. will not be overwritten when the suspend image is * restored) have the corresponding bits set in @bm (it must be * unitialized). * * NOTE: This function should not be called if there are no highmem * image pages. */ static unsigned int safe_highmem_pages; static struct memory_bitmap *safe_highmem_bm; static int prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p) { unsigned int to_alloc; if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE)) return -ENOMEM; if (get_highmem_buffer(PG_SAFE)) return -ENOMEM; to_alloc = count_free_highmem_pages(); if (to_alloc > *nr_highmem_p) to_alloc = *nr_highmem_p; else *nr_highmem_p = to_alloc; safe_highmem_pages = 0; while (to_alloc-- > 0) { struct page *page; page = alloc_page(__GFP_HIGHMEM); if (!swsusp_page_is_free(page)) { /* The page is "safe", set its bit the bitmap */ memory_bm_set_bit(bm, page_to_pfn(page)); safe_highmem_pages++; } /* Mark the page as allocated */ swsusp_set_page_forbidden(page); swsusp_set_page_free(page); } memory_bm_position_reset(bm); safe_highmem_bm = bm; return 0; } /** * get_highmem_page_buffer - for given highmem image page find the buffer * that suspend_write_next() should set for its caller to write to. * * If the page is to be saved to its "original" page frame or a copy of * the page is to be made in the highmem, @buffer is returned. Otherwise, * the copy of the page is to be made in normal memory, so the address of * the copy is returned. * * If @buffer is returned, the caller of suspend_write_next() will write * the page's contents to @buffer, so they will have to be copied to the * right location on the next call to suspend_write_next() and it is done * with the help of copy_last_highmem_page(). For this purpose, if * @buffer is returned, @last_highmem page is set to the page to which * the data will have to be copied from @buffer. */ static struct page *last_highmem_page; static void * get_highmem_page_buffer(struct page *page, struct chain_allocator *ca) { struct highmem_pbe *pbe; void *kaddr; if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) { /* We have allocated the "original" page frame and we can * use it directly to store the loaded page. */ last_highmem_page = page; return buffer; } /* The "original" page frame has not been allocated and we have to * use a "safe" page frame to store the loaded page. */ pbe = chain_alloc(ca, sizeof(struct highmem_pbe)); if (!pbe) { swsusp_free(); return ERR_PTR(-ENOMEM); } pbe->orig_page = page; if (safe_highmem_pages > 0) { struct page *tmp; /* Copy of the page will be stored in high memory */ kaddr = buffer; tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm)); safe_highmem_pages--; last_highmem_page = tmp; pbe->copy_page = tmp; } else { /* Copy of the page will be stored in normal memory */ kaddr = safe_pages_list; safe_pages_list = safe_pages_list->next; pbe->copy_page = virt_to_page(kaddr); } pbe->next = highmem_pblist; highmem_pblist = pbe; return kaddr; } /** * copy_last_highmem_page - copy the contents of a highmem image from * @buffer, where the caller of snapshot_write_next() has place them, * to the right location represented by @last_highmem_page . */ static void copy_last_highmem_page(void) { if (last_highmem_page) { void *dst; dst = kmap_atomic(last_highmem_page, KM_USER0); copy_page(dst, buffer); kunmap_atomic(dst, KM_USER0); last_highmem_page = NULL; } } static inline int last_highmem_page_copied(void) { return !last_highmem_page; } static inline void free_highmem_data(void) { if (safe_highmem_bm) memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR); if (buffer) free_image_page(buffer, PG_UNSAFE_CLEAR); } #else static inline int get_safe_write_buffer(void) { return 0; } static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { return 0; } static inline int prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p) { return 0; } static inline void * get_highmem_page_buffer(struct page *page, struct chain_allocator *ca) { return ERR_PTR(-EINVAL); } static inline void copy_last_highmem_page(void) {} static inline int last_highmem_page_copied(void) { return 1; } static inline void free_highmem_data(void) {} #endif /* CONFIG_HIGHMEM */ /** * prepare_image - use the memory bitmap @bm to mark the pages that will * be overwritten in the process of restoring the system memory state * from the suspend image ("unsafe" pages) and allocate memory for the * image. * * The idea is to allocate a new memory bitmap first and then allocate * as many pages as needed for the image data, but not to assign these * pages to specific tasks initially. Instead, we just mark them as * allocated and create a lists of "safe" pages that will be used * later. On systems with high memory a list of "safe" highmem pages is * also created. */ #define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe)) static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm) { unsigned int nr_pages, nr_highmem; struct linked_page *sp_list, *lp; int error; /* If there is no highmem, the buffer will not be necessary */ free_image_page(buffer, PG_UNSAFE_CLEAR); buffer = NULL; nr_highmem = count_highmem_image_pages(bm); error = mark_unsafe_pages(bm); if (error) goto Free; error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE); if (error) goto Free; duplicate_memory_bitmap(new_bm, bm); memory_bm_free(bm, PG_UNSAFE_KEEP); if (nr_highmem > 0) { error = prepare_highmem_image(bm, &nr_highmem); if (error) goto Free; } /* Reserve some safe pages for potential later use. * * NOTE: This way we make sure there will be enough safe pages for the * chain_alloc() in get_buffer(). It is a bit wasteful, but * nr_copy_pages cannot be greater than 50% of the memory anyway. */ sp_list = NULL; /* nr_copy_pages cannot be lesser than allocated_unsafe_pages */ nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages; nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE); while (nr_pages > 0) { lp = get_image_page(GFP_ATOMIC, PG_SAFE); if (!lp) { error = -ENOMEM; goto Free; } lp->next = sp_list; sp_list = lp; nr_pages--; } /* Preallocate memory for the image */ safe_pages_list = NULL; nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages; while (nr_pages > 0) { lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC); if (!lp) { error = -ENOMEM; goto Free; } if (!swsusp_page_is_free(virt_to_page(lp))) { /* The page is "safe", add it to the list */ lp->next = safe_pages_list; safe_pages_list = lp; } /* Mark the page as allocated */ swsusp_set_page_forbidden(virt_to_page(lp)); swsusp_set_page_free(virt_to_page(lp)); nr_pages--; } /* Free the reserved safe pages so that chain_alloc() can use them */ while (sp_list) { lp = sp_list->next; free_image_page(sp_list, PG_UNSAFE_CLEAR); sp_list = lp; } return 0; Free: swsusp_free(); return error; } /** * get_buffer - compute the address that snapshot_write_next() should * set for its caller to write to. */ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca) { struct pbe *pbe; struct page *page; unsigned long pfn = memory_bm_next_pfn(bm); if (pfn == BM_END_OF_MAP) return ERR_PTR(-EFAULT); page = pfn_to_page(pfn); if (PageHighMem(page)) return get_highmem_page_buffer(page, ca); if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) /* We have allocated the "original" page frame and we can * use it directly to store the loaded page. */ return page_address(page); /* The "original" page frame has not been allocated and we have to * use a "safe" page frame to store the loaded page. */ pbe = chain_alloc(ca, sizeof(struct pbe)); if (!pbe) { swsusp_free(); return ERR_PTR(-ENOMEM); } pbe->orig_address = page_address(page); pbe->address = safe_pages_list; safe_pages_list = safe_pages_list->next; pbe->next = restore_pblist; restore_pblist = pbe; return pbe->address; } /** * snapshot_write_next - used for writing the system memory snapshot. * * On the first call to it @handle should point to a zeroed * snapshot_handle structure. The structure gets updated and a pointer * to it should be passed to this function every next time. * * On success the function returns a positive number. Then, the caller * is allowed to write up to the returned number of bytes to the memory * location computed by the data_of() macro. * * The function returns 0 to indicate the "end of file" condition, * and a negative number is returned on error. In such cases the * structure pointed to by @handle is not updated and should not be used * any more. */ int snapshot_write_next(struct snapshot_handle *handle) { static struct chain_allocator ca; int error = 0; /* Check if we have already loaded the entire image */ if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) return 0; handle->sync_read = 1; if (!handle->cur) { if (!buffer) /* This makes the buffer be freed by swsusp_free() */ buffer = get_image_page(GFP_ATOMIC, PG_ANY); if (!buffer) return -ENOMEM; handle->buffer = buffer; } else if (handle->cur == 1) { error = load_header(buffer); if (error) return error; error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY); if (error) return error; /* Allocate buffer for page keys. */ error = page_key_alloc(nr_copy_pages); if (error) return error; } else if (handle->cur <= nr_meta_pages + 1) { error = unpack_orig_pfns(buffer, ©_bm); if (error) return error; if (handle->cur == nr_meta_pages + 1) { error = prepare_image(&orig_bm, ©_bm); if (error) return error; chain_init(&ca, GFP_ATOMIC, PG_SAFE); memory_bm_position_reset(&orig_bm); restore_pblist = NULL; handle->buffer = get_buffer(&orig_bm, &ca); handle->sync_read = 0; if (IS_ERR(handle->buffer)) return PTR_ERR(handle->buffer); } } else { copy_last_highmem_page(); /* Restore page key for data page (s390 only). */ page_key_write(handle->buffer); handle->buffer = get_buffer(&orig_bm, &ca); if (IS_ERR(handle->buffer)) return PTR_ERR(handle->buffer); if (handle->buffer != buffer) handle->sync_read = 0; } handle->cur++; return PAGE_SIZE; } /** * snapshot_write_finalize - must be called after the last call to * snapshot_write_next() in case the last page in the image happens * to be a highmem page and its contents should be stored in the * highmem. Additionally, it releases the memory that will not be * used any more. */ void snapshot_write_finalize(struct snapshot_handle *handle) { copy_last_highmem_page(); /* Restore page key for data page (s390 only). */ page_key_write(handle->buffer); page_key_free(); /* Free only if we have loaded the image entirely */ if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) { memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR); free_highmem_data(); } } int snapshot_image_loaded(struct snapshot_handle *handle) { return !(!nr_copy_pages || !last_highmem_page_copied() || handle->cur <= nr_meta_pages + nr_copy_pages); } #ifdef CONFIG_HIGHMEM /* Assumes that @buf is ready and points to a "safe" page */ static inline void swap_two_pages_data(struct page *p1, struct page *p2, void *buf) { void *kaddr1, *kaddr2; kaddr1 = kmap_atomic(p1, KM_USER0); kaddr2 = kmap_atomic(p2, KM_USER1); copy_page(buf, kaddr1); copy_page(kaddr1, kaddr2); copy_page(kaddr2, buf); kunmap_atomic(kaddr2, KM_USER1); kunmap_atomic(kaddr1, KM_USER0); } /** * restore_highmem - for each highmem page that was allocated before * the suspend and included in the suspend image, and also has been * allocated by the "resume" kernel swap its current (ie. "before * resume") contents with the previous (ie. "before suspend") one. * * If the resume eventually fails, we can call this function once * again and restore the "before resume" highmem state. */ int restore_highmem(void) { struct highmem_pbe *pbe = highmem_pblist; void *buf; if (!pbe) return 0; buf = get_image_page(GFP_ATOMIC, PG_SAFE); if (!buf) return -ENOMEM; while (pbe) { swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf); pbe = pbe->next; } free_image_page(buf, PG_UNSAFE_CLEAR); return 0; } #endif /* CONFIG_HIGHMEM */