// SPDX-License-Identifier: GPL-2.0-only /* * linux/kernel/power/snapshot.c * * This file provides system snapshot/restore functionality for swsusp. * * Copyright (C) 1998-2005 Pavel Machek <[email protected]> * Copyright (C) 2006 Rafael J. Wysocki <[email protected]> */ #define pr_fmt(fmt) … #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/memblock.h> #include <linux/nmi.h> #include <linux/syscalls.h> #include <linux/console.h> #include <linux/highmem.h> #include <linux/list.h> #include <linux/slab.h> #include <linux/compiler.h> #include <linux/ktime.h> #include <linux/set_memory.h> #include <linux/uaccess.h> #include <asm/mmu_context.h> #include <asm/tlbflush.h> #include <asm/io.h> #include "power.h" #if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_ARCH_HAS_SET_MEMORY) static bool hibernate_restore_protection; static bool hibernate_restore_protection_active; void enable_restore_image_protection(void) { … } static inline void hibernate_restore_protection_begin(void) { … } static inline void hibernate_restore_protection_end(void) { … } static inline int __must_check hibernate_restore_protect_page(void *page_address) { … } static inline int hibernate_restore_unprotect_page(void *page_address) { … } #else static inline void hibernate_restore_protection_begin(void) {} static inline void hibernate_restore_protection_end(void) {} static inline int __must_check hibernate_restore_protect_page(void *page_address) {return 0; } static inline int hibernate_restore_unprotect_page(void *page_address) {return 0; } #endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */ /* * The calls to set_direct_map_*() should not fail because remapping a page * here means that we only update protection bits in an existing PTE. * It is still worth to have a warning here if something changes and this * will no longer be the case. */ static inline void hibernate_map_page(struct page *page) { … } static inline void hibernate_unmap_page(struct page *page) { … } 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) { … } /* * 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) { … } /* * 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; /* struct linked_page is used to build chains of pages */ #define LINKED_PAGE_DATA_SIZE … struct linked_page { … } __packed; /* * List of "safe" pages (ie. pages that were not used by the image kernel * before hibernation) that may be used as temporary storage for image kernel * memory contents. */ static struct linked_page *safe_pages_list; /* Pointer to an auxiliary buffer (1 page) */ static void *buffer; #define PG_ANY … #define PG_SAFE … #define PG_UNSAFE_CLEAR … #define PG_UNSAFE_KEEP … static unsigned int allocated_unsafe_pages; /** * get_image_page - Allocate a page for a hibernation image. * @gfp_mask: GFP mask for the allocation. * @safe_needed: Get pages that were not used before hibernation (restore only) * * During image restoration, for storing the PBE list and the image data, we can * only use memory pages that do not conflict with the pages used before * hibernation. The "unsafe" pages have PageNosaveFree set and we count them * using allocated_unsafe_pages. * * Each allocated image page is marked as PageNosave and PageNosaveFree so that * swsusp_free() can release it. */ static void *get_image_page(gfp_t gfp_mask, int safe_needed) { … } static void *__get_safe_page(gfp_t gfp_mask) { … } unsigned long get_safe_page(gfp_t gfp_mask) { … } static struct page *alloc_image_page(gfp_t gfp_mask) { … } static void recycle_safe_page(void *page_address) { … } /** * free_image_page - Free a page allocated for hibernation image. * @addr: Address of the page to free. * @clear_nosave_free: If set, clear the PageNosaveFree bit for the page. * * The page to free should have been allocated by get_image_page() (page flags * set by it are affected). */ static inline void free_image_page(void *addr, int clear_nosave_free) { … } static inline void free_list_of_pages(struct linked_page *list, int clear_page_nosave) { … } /* * 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 { … }; static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed) { … } static void *chain_alloc(struct chain_allocator *ca, unsigned int size) { … } /* * Data types related to memory bitmaps. * * Memory bitmap is a structure consisting of many linked lists of * objects. The main list's elements are of type struct zone_bitmap * and each of them corresponds 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. * * The memory bitmap is organized as a radix tree to guarantee fast random * access to the bits. There is one radix tree for each zone (as returned * from create_mem_extents). * * One radix tree is represented by one struct mem_zone_bm_rtree. There are * two linked lists for the nodes of the tree, one for the inner nodes and * one for the leave nodes. The linked leave nodes are used for fast linear * access of the memory bitmap. * * The struct rtree_node represents one node of the radix tree. */ #define BM_END_OF_MAP … #define BM_BITS_PER_BLOCK … #define BM_BLOCK_SHIFT … #define BM_BLOCK_MASK … /* * struct rtree_node is a wrapper struct to link the nodes * of the rtree together for easy linear iteration over * bits and easy freeing */ struct rtree_node { … }; /* * struct mem_zone_bm_rtree represents a bitmap used for one * populated memory zone. */ struct mem_zone_bm_rtree { … }; /* struct bm_position is used for browsing memory bitmaps */ struct bm_position { … }; struct memory_bitmap { … }; /* Functions that operate on memory bitmaps */ #define BM_ENTRIES_PER_LEVEL … #if BITS_PER_LONG == 32 #define BM_RTREE_LEVEL_SHIFT … #else #define BM_RTREE_LEVEL_SHIFT … #endif #define BM_RTREE_LEVEL_MASK … /** * alloc_rtree_node - Allocate a new node and add it to the radix tree. * @gfp_mask: GFP mask for the allocation. * @safe_needed: Get pages not used before hibernation (restore only) * @ca: Pointer to a linked list of pages ("a chain") to allocate from * @list: Radix Tree node to add. * * This function is used to allocate inner nodes as well as the * leave nodes of the radix tree. It also adds the node to the * corresponding linked list passed in by the *list parameter. */ static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed, struct chain_allocator *ca, struct list_head *list) { … } /** * add_rtree_block - Add a new leave node to the radix tree. * * The leave nodes need to be allocated in order to keep the leaves * linked list in order. This is guaranteed by the zone->blocks * counter. */ static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask, int safe_needed, struct chain_allocator *ca) { … } static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone, int clear_nosave_free); /** * create_zone_bm_rtree - Create a radix tree for one zone. * * Allocated the mem_zone_bm_rtree structure and initializes it. * This function also allocated and builds the radix tree for the * zone. */ static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask, int safe_needed, struct chain_allocator *ca, unsigned long start, unsigned long end) { … } /** * free_zone_bm_rtree - Free the memory of the radix tree. * * Free all node pages of the radix tree. The mem_zone_bm_rtree * structure itself is not freed here nor are the rtree_node * structs. */ static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone, int clear_nosave_free) { … } static void memory_bm_position_reset(struct memory_bitmap *bm) { … } static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free); struct mem_extent { … }; /** * free_mem_extents - Free a list of memory extents. * @list: List of extents to free. */ static void free_mem_extents(struct list_head *list) { … } /** * create_mem_extents - Create a list of memory extents. * @list: List to put the extents into. * @gfp_mask: Mask to use for memory allocations. * * The extents represent contiguous ranges of PFNs. */ static int create_mem_extents(struct list_head *list, gfp_t gfp_mask) { … } /** * 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) { … } /** * memory_bm_free - Free memory occupied by the memory bitmap. * @bm: Memory bitmap. */ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free) { … } /** * memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap. * * Find the bit in memory bitmap @bm that corresponds to the given PFN. * The cur.zone, cur.block and cur.node_pfn members of @bm are updated. * * Walk the radix tree to find the page containing the bit that represents @pfn * and return the position of the bit in @addr and @bit_nr. */ static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, void **addr, unsigned int *bit_nr) { … } static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn) { … } static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn) { … } static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn) { … } static void memory_bm_clear_current(struct memory_bitmap *bm) { … } static unsigned long memory_bm_get_current(struct memory_bitmap *bm) { … } static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn) { … } static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn) { … } /* * rtree_next_node - Jump to the next leaf node. * * Set the position to the beginning of the next node in the * memory bitmap. This is either the next node in the current * zone's radix tree or the first node in the radix tree of the * next zone. * * Return true if there is a next node, false otherwise. */ static bool rtree_next_node(struct memory_bitmap *bm) { … } /** * memory_bm_next_pfn - Find the next set bit in a memory bitmap. * @bm: Memory bitmap. * * Starting from the last returned position this function searches for the next * set bit in @bm and returns the PFN represented by it. If no more bits are * set, BM_END_OF_MAP is returned. * * It is required to run memory_bm_position_reset() before the first call to * this function for the given memory bitmap. */ static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm) { … } /* * This structure represents a range of page frames the contents of which * should not be saved during hibernation. */ struct nosave_region { … }; static LIST_HEAD(nosave_regions); static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone) { … } static void memory_bm_recycle(struct memory_bitmap *bm) { … } /** * register_nosave_region - Register a region of unsaveable memory. * * Register a range of page frames the contents of which should not be saved * during hibernation (to be used in the early initialization code). */ void __init register_nosave_region(unsigned long start_pfn, unsigned long end_pfn) { … } /* * 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) { … } static int swsusp_page_is_free(struct page *page) { … } void swsusp_unset_page_free(struct page *page) { … } static void swsusp_set_page_forbidden(struct page *page) { … } int swsusp_page_is_forbidden(struct page *page) { … } static void swsusp_unset_page_forbidden(struct page *page) { … } /** * mark_nosave_pages - Mark pages that should not be saved. * @bm: Memory bitmap. * * Set the bits in @bm that correspond to the page frames the contents of which * should not be saved. */ static void mark_nosave_pages(struct memory_bitmap *bm) { … } /** * create_basic_memory_bitmaps - Create bitmaps to hold basic page information. * * Create bitmaps needed for marking page frames that should not be saved and * free page frames. The forbidden_pages_map and free_pages_map pointers are * only modified if everything goes well, because we don't want the bits to be * touched before both bitmaps are set up. */ int create_basic_memory_bitmaps(void) { … } /** * free_basic_memory_bitmaps - Free memory bitmaps holding basic information. * * 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) { … } static void clear_or_poison_free_page(struct page *page) { … } void clear_or_poison_free_pages(void) { … } /** * snapshot_additional_pages - Estimate the number of extra pages needed. * @zone: Memory zone to carry out the computation for. * * Estimate the number of additional pages needed for setting up a hibernation * image data structures for @zone (usually, the returned value is greater than * the exact number). */ unsigned int snapshot_additional_pages(struct zone *zone) { … } /* * Touch the watchdog for every WD_PAGE_COUNT pages. */ #define WD_PAGE_COUNT … static void mark_free_pages(struct zone *zone) { … } #ifdef CONFIG_HIGHMEM /** * count_free_highmem_pages - Compute the total number of free highmem pages. * * The returned number is 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 - Check if a highmem page is saveable. * * Determine whether a highmem page should be included in a hibernation image. * * We should save the page if it isn't Nosave or NosaveFree, or Reserved, * and it isn't 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_online_page(pfn); if (!page || 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) || PageOffline(page)) return NULL; if (page_is_guard(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_end_pfn(zone); 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) { … } #endif /* CONFIG_HIGHMEM */ /** * saveable_page - Check if the given page is saveable. * * Determine whether a non-highmem page should be included in a hibernation * 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 part of * a free chunk of pages. */ static struct page *saveable_page(struct zone *zone, unsigned long pfn) { … } /** * count_data_pages - Compute the total number of saveable non-highmem pages. */ static unsigned int count_data_pages(void) { … } /* * This is needed, because copy_page and memcpy are not usable for copying * task structs. Returns true if the page was filled with only zeros, * otherwise false. */ static inline bool do_copy_page(long *dst, long *src) { … } /** * safe_copy_page - Copy a page in a safe way. * * 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 or * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present() * always returns 'true'. Returns true if the page was entirely composed of * zeros, otherwise it will return false. */ static bool safe_copy_page(void *dst, struct page *s_page) { … } #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 bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn) { struct page *s_page, *d_page; void *src, *dst; bool zeros_only; s_page = pfn_to_page(src_pfn); d_page = pfn_to_page(dst_pfn); if (PageHighMem(s_page)) { src = kmap_local_page(s_page); dst = kmap_local_page(d_page); zeros_only = do_copy_page(dst, src); kunmap_local(dst); kunmap_local(src); } else { if (PageHighMem(d_page)) { /* * The page pointed to by src may contain some kernel * data modified by kmap_atomic() */ zeros_only = safe_copy_page(buffer, s_page); dst = kmap_local_page(d_page); copy_page(dst, buffer); kunmap_local(dst); } else { zeros_only = safe_copy_page(page_address(d_page), s_page); } } return zeros_only; } #else #define page_is_saveable(zone, pfn) … static inline int copy_data_page(unsigned long dst_pfn, unsigned long src_pfn) { … } #endif /* CONFIG_HIGHMEM */ /* * Copy data pages will copy all pages into pages pulled from the copy_bm. * If a page was entirely filled with zeros it will be marked in the zero_bm. * * Returns the number of pages copied. */ static unsigned long copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm, struct memory_bitmap *zero_bm) { … } /* 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; /* Number of zero pages */ static unsigned int nr_zero_pages; /* * Numbers of normal and highmem page frames allocated for hibernation image * before suspending devices. */ static 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; /* Memory bitmap which tracks which saveable pages were zero filled. */ static struct memory_bitmap zero_bm; /** * swsusp_free - Free pages allocated for hibernation image. * * Image pages are allocated before snapshot creation, so they need to be * released after resume. */ void swsusp_free(void) { … } /* Helper functions used for the shrinking of memory. */ #define GFP_IMAGE … /** * 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) { … } static unsigned long preallocate_image_memory(unsigned long nr_pages, unsigned long avail_normal) { … } #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) { return div64_u64(x * multiplier, base); } 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) { … } static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages, unsigned long highmem, unsigned long total) { … } #endif /* CONFIG_HIGHMEM */ /** * free_unnecessary_pages - Release preallocated pages not needed for the image. */ static unsigned long free_unnecessary_pages(void) { … } /** * 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 anonymous pages, (4) active and (5) inactive file pages. */ static unsigned long minimum_image_size(unsigned long saveable) { … } /** * 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 reserved_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) { … } #ifdef CONFIG_HIGHMEM /** * count_pages_for_highmem - Count non-highmem pages needed for copying 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) { … } #endif /* CONFIG_HIGHMEM */ /** * enough_free_mem - Check if there is enough free memory for the image. */ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) { … } #ifdef CONFIG_HIGHMEM /** * get_highmem_buffer - Allocate a buffer for highmem pages. * * If there are some highmem pages in the hibernation image, we may need a * buffer to copy them and/or load their data. */ static inline int get_highmem_buffer(int safe_needed) { buffer = get_image_page(GFP_ATOMIC, safe_needed); return buffer ? 0 : -ENOMEM; } /** * alloc_highmem_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 less 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|__GFP_KSWAPD_RECLAIM); memory_bm_set_bit(bm, page_to_pfn(page)); } return nr_highmem; } #else static inline int get_highmem_buffer(int safe_needed) { … } static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, unsigned int n) { … } #endif /* CONFIG_HIGHMEM */ /** * swsusp_alloc - Allocate memory for hibernation 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 *copy_bm, unsigned int nr_pages, unsigned int nr_highmem) { … } asmlinkage __visible int swsusp_save(void) { … } #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 const 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) { … } static int init_header(struct swsusp_info *info) { … } #define ENCODED_PFN_ZERO_FLAG … #define ENCODED_PFN_MASK … /** * pack_pfns - Prepare PFNs for saving. * @bm: Memory bitmap. * @buf: Memory buffer to store the PFNs in. * @zero_bm: Memory bitmap containing PFNs of zero pages. * * PFNs corresponding to set bits in @bm are stored in the area of memory * pointed to by @buf (1 page at a time). Pages which were filled with only * zeros will have the highest bit set in the packed format to distinguish * them from PFNs which will be contained in the image file. */ static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm, struct memory_bitmap *zero_bm) { … } /** * snapshot_read_next - Get the address to read the next image page from. * @handle: Snapshot handle to be used for the reading. * * On the first call, @handle should point to a zeroed snapshot_handle * structure. The structure gets populated then 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 the data stream condition, * and negative numbers are returned on errors. If that happens, the structure * pointed to by @handle is not updated and should not be used any more. */ int snapshot_read_next(struct snapshot_handle *handle) { … } static void duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src) { … } /** * mark_unsafe_pages - Mark pages that were used before hibernation. * * Mark the pages that cannot be used for storing the image during restoration, * because they conflict with the pages that had been used before hibernation. */ static void mark_unsafe_pages(struct memory_bitmap *bm) { … } static int check_header(struct swsusp_info *info) { … } /** * load_header - Check the image header and copy the data from it. */ static int load_header(struct swsusp_info *info) { … } /** * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap. * @bm: Memory bitmap. * @buf: Area of memory containing the PFNs. * @zero_bm: Memory bitmap with the zero PFNs marked. * * For each element of the array pointed to by @buf (1 page at a time), set the * corresponding bit in @bm. If the page was originally populated with only * zeros then a corresponding bit will also be set in @zero_bm. */ static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm, struct memory_bitmap *zero_bm) { … } #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 image. * @bm: Memory bitmap. * * The bits in @bm that correspond to 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; } static unsigned int safe_highmem_pages; static struct memory_bitmap *safe_highmem_bm; /** * prepare_highmem_image - Allocate memory for loading highmem data from image. * @bm: Pointer to an uninitialized memory bitmap structure. * @nr_highmem_p: Pointer to the number of highmem image pages. * * 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 * hibernation image is restored entirely) have the corresponding bits set in * @bm (it must be uninitialized). * * NOTE: This function should not be called if there are no highmem image pages. */ 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; } static struct page *last_highmem_page; /** * get_highmem_page_buffer - Prepare a buffer to store a highmem image page. * * For a given highmem image page get a buffer that suspend_write_next() should * return to 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 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 = __get_safe_page(ca->gfp_mask); if (!kaddr) return ERR_PTR(-ENOMEM); pbe->copy_page = virt_to_page(kaddr); } pbe->next = highmem_pblist; highmem_pblist = pbe; return kaddr; } /** * copy_last_highmem_page - Copy most the most recent highmem image page. * * Copy the contents of a highmem image from @buffer, where the caller of * snapshot_write_next() has stored 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); copy_page(dst, buffer); kunmap_atomic(dst); 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 unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { … } static inline int prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p) { … } static inline void *get_highmem_page_buffer(struct page *page, struct chain_allocator *ca) { … } static inline void copy_last_highmem_page(void) { … } static inline int last_highmem_page_copied(void) { … } static inline void free_highmem_data(void) { … } #endif /* CONFIG_HIGHMEM */ #define PBES_PER_LINKED_PAGE … /** * prepare_image - Make room for loading hibernation image. * @new_bm: Uninitialized memory bitmap structure. * @bm: Memory bitmap with unsafe pages marked. * @zero_bm: Memory bitmap containing the zero pages. * * Use @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 image data, but without specifying what those * pages will be used for just yet. Instead, we mark them all as allocated and * create a lists of "safe" pages to be used later. On systems with high * memory a list of "safe" highmem pages is created too. * * Because it was not known which pages were unsafe when @zero_bm was created, * make a copy of it and recreate it within safe pages. */ static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm, struct memory_bitmap *zero_bm) { … } /** * get_buffer - Get the address to store the next image data page. * * Get the address that snapshot_write_next() should return to its caller to * write to. */ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca) { … } /** * snapshot_write_next - Get the address to store the next image page. * @handle: Snapshot handle structure to guide the writing. * * On the first call, @handle should point to a zeroed snapshot_handle * structure. The structure gets populated then 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. Negative * numbers are returned on errors, in which 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) { … } /** * snapshot_write_finalize - Complete the loading of a hibernation image. * * 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 highmem. Additionally, it recycles bitmap memory that's not * necessary any more. */ int snapshot_write_finalize(struct snapshot_handle *handle) { … } int snapshot_image_loaded(struct snapshot_handle *handle) { … } #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); kaddr2 = kmap_atomic(p2); copy_page(buf, kaddr1); copy_page(kaddr1, kaddr2); copy_page(kaddr2, buf); kunmap_atomic(kaddr2); kunmap_atomic(kaddr1); } /** * restore_highmem - Put highmem image pages into their original locations. * * For each highmem page that was in use before hibernation and is included in * the image, and also has been allocated by the "restore" kernel, swap its * current contents with the previous (ie. "before hibernation") ones. * * If the restore eventually fails, we can call this function once again and * restore the highmem state as seen by the restore kernel. */ 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 */
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