snapshot.c 44.1 KB
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/*
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 * linux/kernel/power/snapshot.c
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 *
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 * This file provides system snapshot/restore functionality for swsusp.
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 *
 * Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
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 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
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 *
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 * This file is released under the GPLv2.
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 *
 */

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#include <linux/version.h>
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#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/smp_lock.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/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.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"

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/* 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.
 */
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struct pbe *restore_pblist;

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/* Pointer to an auxiliary buffer (1 page) */
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static void *buffer;
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/**
 *	@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
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 *	used before suspend.  The unsafe pages have PageNosaveFree set
 *	and we count them using unsafe_pages.
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 *
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 *	Each allocated image page is marked as PageNosave and PageNosaveFree
 *	so that swsusp_free() can release it.
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 */

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#define PG_ANY		0
#define PG_SAFE		1
#define PG_UNSAFE_CLEAR	1
#define PG_UNSAFE_KEEP	0

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static unsigned int allocated_unsafe_pages;
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static void *get_image_page(gfp_t gfp_mask, int safe_needed)
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{
	void *res;

	res = (void *)get_zeroed_page(gfp_mask);
	if (safe_needed)
		while (res && PageNosaveFree(virt_to_page(res))) {
			/* The page is unsafe, mark it for swsusp_free() */
			SetPageNosave(virt_to_page(res));
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			allocated_unsafe_pages++;
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			res = (void *)get_zeroed_page(gfp_mask);
		}
	if (res) {
		SetPageNosave(virt_to_page(res));
		SetPageNosaveFree(virt_to_page(res));
	}
	return res;
}

unsigned long get_safe_page(gfp_t gfp_mask)
{
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	return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
}

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static struct page *alloc_image_page(gfp_t gfp_mask)
{
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	struct page *page;

	page = alloc_page(gfp_mask);
	if (page) {
		SetPageNosave(page);
		SetPageNosaveFree(page);
	}
	return page;
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}

/**
 *	free_image_page - free page represented by @addr, allocated with
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 *	get_image_page (page flags set by it must be cleared)
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 */

static inline void free_image_page(void *addr, int clear_nosave_free)
{
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	struct page *page;

	BUG_ON(!virt_addr_valid(addr));

	page = virt_to_page(addr);

	ClearPageNosave(page);
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	if (clear_nosave_free)
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		ClearPageNosaveFree(page);

	__free_page(page);
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}

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/* 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;

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		lp = get_image_page(ca->gfp_mask, ca->safe_needed);
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		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;
}

static void chain_free(struct chain_allocator *ca, int clear_page_nosave)
{
	free_list_of_pages(ca->chain, clear_page_nosave);
	memset(ca, 0, sizeof(struct chain_allocator));
}

/**
 *	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 bit chunks 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 bit chunks
 *	of type unsigned long each).  It also contains the pfns that
 *	correspond to the start and end of the represented memory area and
 *	the number of bit chunks in the block.
 *
 *	NOTE: Memory bitmaps are used for two types of operations only:
 *	"set a bit" and "find the next bit set".  Moreover, the searching
 *	is always carried out after all of the "set a bit" operations
 *	on given bitmap.
 */

#define BM_END_OF_MAP	(~0UL)

#define BM_CHUNKS_PER_BLOCK	(PAGE_SIZE / sizeof(long))
#define BM_BITS_PER_CHUNK	(sizeof(long) << 3)
#define BM_BITS_PER_BLOCK	(PAGE_SIZE << 3)

struct bm_block {
	struct bm_block *next;		/* next element of the list */
	unsigned long start_pfn;	/* pfn represented by the first bit */
	unsigned long end_pfn;	/* pfn represented by the last bit plus 1 */
	unsigned int size;	/* number of bit chunks */
	unsigned long *data;	/* chunks of bits representing pages */
};

struct zone_bitmap {
	struct zone_bitmap *next;	/* next element of the list */
	unsigned long start_pfn;	/* minimal pfn in this zone */
	unsigned long end_pfn;		/* maximal pfn in this zone plus 1 */
	struct bm_block *bm_blocks;	/* list of bitmap blocks */
	struct bm_block *cur_block;	/* recently used bitmap block */
};

/* strcut bm_position is used for browsing memory bitmaps */

struct bm_position {
	struct zone_bitmap *zone_bm;
	struct bm_block *block;
	int chunk;
	int bit;
};

struct memory_bitmap {
	struct zone_bitmap *zone_bm_list;	/* list of zone bitmaps */
	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 inline void memory_bm_reset_chunk(struct memory_bitmap *bm)
{
	bm->cur.chunk = 0;
	bm->cur.bit = -1;
}

static void memory_bm_position_reset(struct memory_bitmap *bm)
{
	struct zone_bitmap *zone_bm;

	zone_bm = bm->zone_bm_list;
	bm->cur.zone_bm = zone_bm;
	bm->cur.block = zone_bm->bm_blocks;
	memory_bm_reset_chunk(bm);
}

static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);

/**
 *	create_bm_block_list - create a list of block bitmap objects
 */

static inline struct bm_block *
create_bm_block_list(unsigned int nr_blocks, struct chain_allocator *ca)
{
	struct bm_block *bblist = NULL;

	while (nr_blocks-- > 0) {
		struct bm_block *bb;

		bb = chain_alloc(ca, sizeof(struct bm_block));
		if (!bb)
			return NULL;

		bb->next = bblist;
		bblist = bb;
	}
	return bblist;
}

/**
 *	create_zone_bm_list - create a list of zone bitmap objects
 */

static inline struct zone_bitmap *
create_zone_bm_list(unsigned int nr_zones, struct chain_allocator *ca)
{
	struct zone_bitmap *zbmlist = NULL;

	while (nr_zones-- > 0) {
		struct zone_bitmap *zbm;

		zbm = chain_alloc(ca, sizeof(struct zone_bitmap));
		if (!zbm)
			return NULL;

		zbm->next = zbmlist;
		zbmlist = zbm;
	}
	return zbmlist;
}

/**
  *	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 zone *zone;
	struct zone_bitmap *zone_bm;
	struct bm_block *bb;
	unsigned int nr;

	chain_init(&ca, gfp_mask, safe_needed);

	/* Compute the number of zones */
	nr = 0;
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	for_each_zone(zone)
		if (populated_zone(zone))
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			nr++;

	/* Allocate the list of zones bitmap objects */
	zone_bm = create_zone_bm_list(nr, &ca);
	bm->zone_bm_list = zone_bm;
	if (!zone_bm) {
		chain_free(&ca, PG_UNSAFE_CLEAR);
		return -ENOMEM;
	}

	/* Initialize the zone bitmap objects */
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	for_each_zone(zone) {
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		unsigned long pfn;

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		if (!populated_zone(zone))
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			continue;

		zone_bm->start_pfn = zone->zone_start_pfn;
		zone_bm->end_pfn = zone->zone_start_pfn + zone->spanned_pages;
		/* Allocate the list of bitmap block objects */
		nr = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
		bb = create_bm_block_list(nr, &ca);
		zone_bm->bm_blocks = bb;
		zone_bm->cur_block = bb;
		if (!bb)
			goto Free;

		nr = zone->spanned_pages;
		pfn = zone->zone_start_pfn;
		/* Initialize the bitmap block objects */
		while (bb) {
			unsigned long *ptr;

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			ptr = get_image_page(gfp_mask, safe_needed);
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			bb->data = ptr;
			if (!ptr)
				goto Free;

			bb->start_pfn = pfn;
			if (nr >= BM_BITS_PER_BLOCK) {
				pfn += BM_BITS_PER_BLOCK;
				bb->size = BM_CHUNKS_PER_BLOCK;
				nr -= BM_BITS_PER_BLOCK;
			} else {
				/* This is executed only once in the loop */
				pfn += nr;
				bb->size = DIV_ROUND_UP(nr, BM_BITS_PER_CHUNK);
			}
			bb->end_pfn = pfn;
			bb = bb->next;
		}
		zone_bm = zone_bm->next;
	}
	bm->p_list = ca.chain;
	memory_bm_position_reset(bm);
	return 0;

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	bm->p_list = ca.chain;
	memory_bm_free(bm, PG_UNSAFE_CLEAR);
	return -ENOMEM;
}

/**
  *	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 zone_bitmap *zone_bm;

	/* Free the list of bit blocks for each zone_bitmap object */
	zone_bm = bm->zone_bm_list;
	while (zone_bm) {
		struct bm_block *bb;

		bb = zone_bm->bm_blocks;
		while (bb) {
			if (bb->data)
				free_image_page(bb->data, clear_nosave_free);
			bb = bb->next;
		}
		zone_bm = zone_bm->next;
	}
	free_list_of_pages(bm->p_list, clear_nosave_free);
	bm->zone_bm_list = NULL;
}

/**
 *	memory_bm_set_bit - set 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.
 *
 *	If the bit cannot be set, the function returns -EINVAL .
 */

static int
memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
{
	struct zone_bitmap *zone_bm;
	struct bm_block *bb;

	/* Check if the pfn is from the current zone */
	zone_bm = bm->cur.zone_bm;
	if (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {
		zone_bm = bm->zone_bm_list;
		/* We don't assume that the zones are sorted by pfns */
		while (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {
			zone_bm = zone_bm->next;
			if (unlikely(!zone_bm))
				return -EINVAL;
		}
		bm->cur.zone_bm = zone_bm;
	}
	/* Check if the pfn corresponds to the current bitmap block */
	bb = zone_bm->cur_block;
	if (pfn < bb->start_pfn)
		bb = zone_bm->bm_blocks;

	while (pfn >= bb->end_pfn) {
		bb = bb->next;
		if (unlikely(!bb))
			return -EINVAL;
	}
	zone_bm->cur_block = bb;
	pfn -= bb->start_pfn;
	set_bit(pfn % BM_BITS_PER_CHUNK, bb->data + pfn / BM_BITS_PER_CHUNK);
	return 0;
}

/* Two auxiliary functions for memory_bm_next_pfn */

/* Find the first set bit in the given chunk, if there is one */

static inline int next_bit_in_chunk(int bit, unsigned long *chunk_p)
{
	bit++;
	while (bit < BM_BITS_PER_CHUNK) {
		if (test_bit(bit, chunk_p))
			return bit;

		bit++;
	}
	return -1;
}

/* Find a chunk containing some bits set in given block of bits */

static inline int next_chunk_in_block(int n, struct bm_block *bb)
{
	n++;
	while (n < bb->size) {
		if (bb->data[n])
			return n;

		n++;
	}
	return -1;
}

/**
 *	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 zone_bitmap *zone_bm;
	struct bm_block *bb;
	int chunk;
	int bit;

	do {
		bb = bm->cur.block;
		do {
			chunk = bm->cur.chunk;
			bit = bm->cur.bit;
			do {
				bit = next_bit_in_chunk(bit, bb->data + chunk);
				if (bit >= 0)
					goto Return_pfn;

				chunk = next_chunk_in_block(chunk, bb);
				bit = -1;
			} while (chunk >= 0);
			bb = bb->next;
			bm->cur.block = bb;
			memory_bm_reset_chunk(bm);
		} while (bb);
		zone_bm = bm->cur.zone_bm->next;
		if (zone_bm) {
			bm->cur.zone_bm = zone_bm;
			bm->cur.block = zone_bm->bm_blocks;
			memory_bm_reset_chunk(bm);
		}
	} while (zone_bm);
	memory_bm_position_reset(bm);
	return BM_END_OF_MAP;

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	bm->cur.chunk = chunk;
	bm->cur.bit = bit;
	return bb->start_pfn + chunk * BM_BITS_PER_CHUNK + bit;
}

/**
 *	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);
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	return 2 * res;
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}

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#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_zone(zone)
		if (populated_zone(zone) && is_highmem(zone))
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			cnt += zone_page_state(zone, NR_FREE_PAGES);
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	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(unsigned long pfn)
{
	struct page *page;

	if (!pfn_valid(pfn))
		return NULL;

	page = pfn_to_page(pfn);

	BUG_ON(!PageHighMem(page));

	if (PageNosave(page) || PageReserved(page) || PageNosaveFree(page))
		return NULL;

	return page;
}

/**
 *	count_highmem_pages - compute the total number of saveable highmem
 *	pages.
 */

unsigned int count_highmem_pages(void)
{
	struct zone *zone;
	unsigned int n = 0;

	for_each_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(pfn))
				n++;
	}
	return n;
}
#else
static inline void *saveable_highmem_page(unsigned long pfn) { return NULL; }
static inline unsigned int count_highmem_pages(void) { return 0; }
#endif /* CONFIG_HIGHMEM */

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/**
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 *	saveable - Determine whether a non-highmem page should be included in
 *	the suspend image.
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 *
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 *	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.
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 */

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static struct page *saveable_page(unsigned long pfn)
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{
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	struct page *page;
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	if (!pfn_valid(pfn))
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		return NULL;
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	page = pfn_to_page(pfn);
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	BUG_ON(PageHighMem(page));

	if (PageNosave(page) || PageNosaveFree(page))
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		return NULL;
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	if (PageReserved(page) && pfn_is_nosave(pfn))
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		return NULL;
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	return page;
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}

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/**
 *	count_data_pages - compute the total number of saveable non-highmem
 *	pages.
 */

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unsigned int count_data_pages(void)
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{
	struct zone *zone;
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	unsigned long pfn, max_zone_pfn;
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	unsigned int n = 0;
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	for_each_zone(zone) {
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		if (is_highmem(zone))
			continue;
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		mark_free_pages(zone);
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		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
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			if(saveable_page(pfn))
				n++;
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	}
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	return n;
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}

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/* 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)
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{
	int n;

	for (n = PAGE_SIZE / sizeof(long); n; n--)
		*dst++ = *src++;
}

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#ifdef CONFIG_HIGHMEM
static inline struct page *
page_is_saveable(struct zone *zone, unsigned long pfn)
{
	return is_highmem(zone) ?
			saveable_highmem_page(pfn) : saveable_page(pfn);
}

static inline 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(src, KM_USER0);
		kunmap_atomic(dst, KM_USER1);
	} else {
		src = page_address(s_page);
		if (PageHighMem(d_page)) {
			/* Page pointed to by src may contain some kernel
			 * data modified by kmap_atomic()
			 */
			do_copy_page(buffer, src);
			dst = kmap_atomic(pfn_to_page(dst_pfn), KM_USER0);
			memcpy(dst, buffer, PAGE_SIZE);
			kunmap_atomic(dst, KM_USER0);
		} else {
			dst = page_address(d_page);
			do_copy_page(dst, src);
		}
	}
}
#else
#define page_is_saveable(zone, pfn)	saveable_page(pfn)

static inline void
copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
	do_copy_page(page_address(pfn_to_page(dst_pfn)),
			page_address(pfn_to_page(src_pfn)));
}
#endif /* CONFIG_HIGHMEM */

766 767
static void
copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
768 769
{
	struct zone *zone;
770
	unsigned long pfn;
771

772
	for_each_zone(zone) {
773 774
		unsigned long max_zone_pfn;

775
		mark_free_pages(zone);
776
		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
777
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
778
			if (page_is_saveable(zone, pfn))
779
				memory_bm_set_bit(orig_bm, pfn);
780
	}
781 782 783 784
	memory_bm_position_reset(orig_bm);
	memory_bm_position_reset(copy_bm);
	do {
		pfn = memory_bm_next_pfn(orig_bm);
785 786
		if (likely(pfn != BM_END_OF_MAP))
			copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
787
	} while (pfn != BM_END_OF_MAP);
788 789
}

790 791 792 793 794
/* 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;

795
/**
796
 *	swsusp_free - free pages allocated for the suspend.
797
 *
798 799
 *	Suspend pages are alocated before the atomic copy is made, so we
 *	need to release them after the resume.
800 801 802 803 804
 */

void swsusp_free(void)
{
	struct zone *zone;
805
	unsigned long pfn, max_zone_pfn;
806 807

	for_each_zone(zone) {
808 809 810 811 812
		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);

813 814 815
				if (PageNosave(page) && PageNosaveFree(page)) {
					ClearPageNosave(page);
					ClearPageNosaveFree(page);
816
					__free_page(page);
817 818 819
				}
			}
	}
820 821
	nr_copy_pages = 0;
	nr_meta_pages = 0;
822
	restore_pblist = NULL;
823
	buffer = NULL;
824 825
}

826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846
#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();

	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 */
847 848

/**
849 850
 *	enough_free_mem - Make sure we have enough free memory for the
 *	snapshot image.
851 852
 */

853
static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
854
{
855
	struct zone *zone;
856
	unsigned int free = 0, meta = 0;
857

858 859 860
	for_each_zone(zone) {
		meta += snapshot_additional_pages(zone);
		if (!is_highmem(zone))
861
			free += zone_page_state(zone, NR_FREE_PAGES);
862
	}
863

864 865
	nr_pages += count_pages_for_highmem(nr_highmem);
	pr_debug("swsusp: Normal pages needed: %u + %u + %u, available pages: %u\n",
866 867 868
		nr_pages, PAGES_FOR_IO, meta, free);

	return free > nr_pages + PAGES_FOR_IO + meta;
869 870
}

871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924
#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_image_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_image_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.
 */

925 926
static int
swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
927
		unsigned int nr_pages, unsigned int nr_highmem)
928
{
929
	int error;
930

931 932 933
	error = memory_bm_create(orig_bm, GFP_ATOMIC | __GFP_COLD, PG_ANY);
	if (error)
		goto Free;
934

935 936 937
	error = memory_bm_create(copy_bm, GFP_ATOMIC | __GFP_COLD, PG_ANY);
	if (error)
		goto Free;
938

939 940 941 942 943 944 945
	if (nr_highmem > 0) {
		error = get_highmem_buffer(PG_ANY);
		if (error)
			goto Free;

		nr_pages += alloc_highmem_image_pages(copy_bm, nr_highmem);
	}
946
	while (nr_pages-- > 0) {
947 948
		struct page *page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);

949 950
		if (!page)
			goto Free;
951

952
		memory_bm_set_bit(copy_bm, page_to_pfn(page));
953
	}
954
	return 0;
955

R
Rafael J. Wysocki 已提交
956
 Free:
957 958
	swsusp_free();
	return -ENOMEM;
959 960
}

961 962 963
/* Memory bitmap used for marking saveable pages (during suspend) or the
 * suspend image pages (during resume)
 */
964
static struct memory_bitmap orig_bm;
965 966 967 968 969 970
/* Memory bitmap used on suspend for marking allocated pages that will contain
 * the copies of saveable pages.  During resume it is initially used for
 * marking the suspend image pages, but then its set bits are duplicated in
 * @orig_bm and it is released.  Next, on systems with high memory, it may be
 * used for marking "safe" highmem pages, but it has to be reinitialized for
 * this purpose.
971 972 973
 */
static struct memory_bitmap copy_bm;

974
asmlinkage int swsusp_save(void)
975
{
976
	unsigned int nr_pages, nr_highmem;
977

978
	printk("swsusp: critical section: \n");
979 980

	drain_local_pages();
981
	nr_pages = count_data_pages();
982 983
	nr_highmem = count_highmem_pages();
	printk("swsusp: Need to copy %u pages\n", nr_pages + nr_highmem);
984

985
	if (!enough_free_mem(nr_pages, nr_highmem)) {
986 987 988 989
		printk(KERN_ERR "swsusp: Not enough free memory\n");
		return -ENOMEM;
	}

990 991
	if (swsusp_alloc(&orig_bm, &copy_bm, nr_pages, nr_highmem)) {
		printk(KERN_ERR "swsusp: Memory allocation failed\n");
992
		return -ENOMEM;
993
	}
994 995 996 997 998

	/* During allocating of suspend pagedir, new cold pages may appear.
	 * Kill them.
	 */
	drain_local_pages();
999
	copy_data_pages(&copy_bm, &orig_bm);
1000 1001 1002 1003 1004 1005 1006

	/*
	 * 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.
	 */

1007
	nr_pages += nr_highmem;
1008
	nr_copy_pages = nr_pages;
1009
	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
1010 1011

	printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
1012

1013 1014
	return 0;
}
1015 1016 1017 1018 1019 1020

static void init_header(struct swsusp_info *info)
{
	memset(info, 0, sizeof(struct swsusp_info));
	info->version_code = LINUX_VERSION_CODE;
	info->num_physpages = num_physpages;
1021
	memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
1022 1023 1024
	info->cpus = num_online_cpus();
	info->image_pages = nr_copy_pages;
	info->pages = nr_copy_pages + nr_meta_pages + 1;
1025 1026
	info->size = info->pages;
	info->size <<= PAGE_SHIFT;
1027 1028 1029
}

/**
1030 1031
 *	pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
 *	are stored in the array @buf[] (1 page at a time)
1032 1033
 */

1034
static inline void
1035
pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
1036 1037 1038
{
	int j;

1039
	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1040 1041
		buf[j] = memory_bm_next_pfn(bm);
		if (unlikely(buf[j] == BM_END_OF_MAP))
1042
			break;
1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
	}
}

/**
 *	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.
 *
 *	The @count parameter should contain the number of bytes the caller
 *	wants to read from the snapshot.  It must not be zero.
 *
 *	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 number returned
 *	may be smaller than @count, but this only happens if the read would
 *	cross a page boundary otherwise.
 *
 *	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, size_t count)
{
1070
	if (handle->cur > nr_meta_pages + nr_copy_pages)
1071
		return 0;
1072

1073 1074
	if (!buffer) {
		/* This makes the buffer be freed by swsusp_free() */
1075
		buffer = get_image_page(GFP_ATOMIC, PG_ANY);
1076 1077 1078 1079 1080 1081
		if (!buffer)
			return -ENOMEM;
	}
	if (!handle->offset) {
		init_header((struct swsusp_info *)buffer);
		handle->buffer = buffer;
1082 1083
		memory_bm_position_reset(&orig_bm);
		memory_bm_position_reset(&copy_bm);
1084
	}
1085 1086
	if (handle->prev < handle->cur) {
		if (handle->cur <= nr_meta_pages) {
1087
			memset(buffer, 0, PAGE_SIZE);
1088
			pack_pfns(buffer, &orig_bm);
1089
		} else {
1090
			struct page *page;
1091

1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
			page = pfn_to_page(memory_bm_next_pfn(&copy_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);
				memcpy(buffer, kaddr, PAGE_SIZE);
				kunmap_atomic(kaddr, KM_USER0);
				handle->buffer = buffer;
			} else {
				handle->buffer = page_address(page);
			}
1107
		}
1108
		handle->prev = handle->cur;
1109
	}
1110 1111 1112 1113 1114
	handle->buf_offset = handle->cur_offset;
	if (handle->cur_offset + count >= PAGE_SIZE) {
		count = PAGE_SIZE - handle->cur_offset;
		handle->cur_offset = 0;
		handle->cur++;
1115
	} else {
1116
		handle->cur_offset += count;
1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
	}
	handle->offset += count;
	return count;
}

/**
 *	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
 */

1128
static int mark_unsafe_pages(struct memory_bitmap *bm)
1129 1130
{
	struct zone *zone;
1131
	unsigned long pfn, max_zone_pfn;
1132 1133

	/* Clear page flags */
1134
	for_each_zone(zone) {
1135 1136 1137 1138
		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))
				ClearPageNosaveFree(pfn_to_page(pfn));
1139 1140
	}

1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
	/* 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)))
				SetPageNosaveFree(pfn_to_page(pfn));
			else
				return -EFAULT;
		}
	} while (pfn != BM_END_OF_MAP);
1152

1153
	allocated_unsafe_pages = 0;
1154

1155 1156 1157
	return 0;
}

1158 1159
static void
duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
1160
{
1161 1162 1163 1164 1165 1166 1167
	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);
1168 1169 1170
	}
}

1171
static inline int check_header(struct swsusp_info *info)
1172 1173 1174 1175 1176 1177 1178
{
	char *reason = NULL;

	if (info->version_code != LINUX_VERSION_CODE)
		reason = "kernel version";
	if (info->num_physpages != num_physpages)
		reason = "memory size";
1179
	if (strcmp(info->uts.sysname,init_utsname()->sysname))
1180
		reason = "system type";
1181
	if (strcmp(info->uts.release,init_utsname()->release))
1182
		reason = "kernel release";
1183
	if (strcmp(info->uts.version,init_utsname()->version))
1184
		reason = "version";
1185
	if (strcmp(info->uts.machine,init_utsname()->machine))
1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197
		reason = "machine";
	if (reason) {
		printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
		return -EPERM;
	}
	return 0;
}

/**
 *	load header - check the image header and copy data from it
 */

1198 1199
static int
load_header(struct swsusp_info *info)
1200 1201 1202
{
	int error;

1203
	restore_pblist = NULL;
1204 1205 1206 1207 1208 1209 1210 1211 1212
	error = check_header(info);
	if (!error) {
		nr_copy_pages = info->image_pages;
		nr_meta_pages = info->pages - info->image_pages - 1;
	}
	return error;
}

/**
1213 1214
 *	unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
 *	the corresponding bit in the memory bitmap @bm
1215 1216
 */

1217 1218
static inline void
unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
1219 1220 1221
{
	int j;

1222 1223 1224 1225 1226
	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
		if (unlikely(buf[j] == BM_END_OF_MAP))
			break;

		memory_bm_set_bit(bm, buf[j]);
1227 1228 1229
	}
}

1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441
/* 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 (!PageNosaveFree(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 */
		SetPageNosave(page);
		SetPageNosaveFree(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 (PageNosave(page) && PageNosaveFree(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 NULL;
	}
	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);
		memcpy(dst, buffer, PAGE_SIZE);
		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 NULL;
}

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 */

1442
/**
1443 1444 1445 1446
 *	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.
1447
 *
1448 1449 1450
 *	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
1451 1452 1453
 *	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.
1454 1455
 */

1456 1457 1458 1459
#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)
1460
{
1461
	unsigned int nr_pages, nr_highmem;
1462 1463
	struct linked_page *sp_list, *lp;
	int error;
1464

1465 1466 1467 1468 1469
	/* 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);
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479
	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);
1480 1481 1482 1483 1484
	if (nr_highmem > 0) {
		error = prepare_highmem_image(bm, &nr_highmem);
		if (error)
			goto Free;
	}
1485 1486 1487 1488 1489 1490 1491 1492
	/* 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 */
1493
	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
1494 1495
	nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
	while (nr_pages > 0) {
1496
		lp = get_image_page(GFP_ATOMIC, PG_SAFE);
1497
		if (!lp) {
1498
			error = -ENOMEM;
1499 1500 1501 1502 1503
			goto Free;
		}
		lp->next = sp_list;
		sp_list = lp;
		nr_pages--;
1504
	}
1505 1506
	/* Preallocate memory for the image */
	safe_pages_list = NULL;
1507
	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
1508 1509 1510 1511 1512 1513 1514 1515 1516 1517
	while (nr_pages > 0) {
		lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
		if (!lp) {
			error = -ENOMEM;
			goto Free;
		}
		if (!PageNosaveFree(virt_to_page(lp))) {
			/* The page is "safe", add it to the list */
			lp->next = safe_pages_list;
			safe_pages_list = lp;
1518
		}
1519 1520 1521 1522
		/* Mark the page as allocated */
		SetPageNosave(virt_to_page(lp));
		SetPageNosaveFree(virt_to_page(lp));
		nr_pages--;
1523
	}
1524 1525 1526 1527 1528
	/* 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;
1529
	}
1530 1531
	return 0;

R
Rafael J. Wysocki 已提交
1532
 Free:
1533
	swsusp_free();
1534 1535 1536
	return error;
}

1537 1538 1539 1540 1541 1542
/**
 *	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)
1543
{
1544 1545
	struct pbe *pbe;
	struct page *page = pfn_to_page(memory_bm_next_pfn(bm));
1546

1547 1548 1549
	if (PageHighMem(page))
		return get_highmem_page_buffer(page, ca);

1550 1551 1552
	if (PageNosave(page) && PageNosaveFree(page))
		/* We have allocated the "original" page frame and we can
		 * use it directly to store the loaded page.
1553
		 */
1554 1555 1556 1557
		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.
1558
	 */
1559 1560 1561 1562 1563
	pbe = chain_alloc(ca, sizeof(struct pbe));
	if (!pbe) {
		swsusp_free();
		return NULL;
	}
1564 1565
	pbe->orig_address = page_address(page);
	pbe->address = safe_pages_list;
1566 1567 1568
	safe_pages_list = safe_pages_list->next;
	pbe->next = restore_pblist;
	restore_pblist = pbe;
1569
	return pbe->address;
1570 1571
}

1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595
/**
 *	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.
 *
 *	The @count parameter should contain the number of bytes the caller
 *	wants to write to the image.  It must not be zero.
 *
 *	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 number returned
 *	may be smaller than @count, but this only happens if the write would
 *	cross a page boundary otherwise.
 *
 *	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, size_t count)
{
1596
	static struct chain_allocator ca;
1597 1598
	int error = 0;

1599
	/* Check if we have already loaded the entire image */
1600
	if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages)
1601
		return 0;
1602

1603 1604 1605 1606 1607
	if (handle->offset == 0) {
		if (!buffer)
			/* This makes the buffer be freed by swsusp_free() */
			buffer = get_image_page(GFP_ATOMIC, PG_ANY);

1608 1609
		if (!buffer)
			return -ENOMEM;
1610

1611
		handle->buffer = buffer;
1612
	}
A
Andrew Morton 已提交
1613
	handle->sync_read = 1;
1614
	if (handle->prev < handle->cur) {
1615 1616 1617 1618 1619 1620
		if (handle->prev == 0) {
			error = load_header(buffer);
			if (error)
				return error;

			error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
1621 1622
			if (error)
				return error;
1623

1624
		} else if (handle->prev <= nr_meta_pages) {
1625 1626 1627
			unpack_orig_pfns(buffer, &copy_bm);
			if (handle->prev == nr_meta_pages) {
				error = prepare_image(&orig_bm, &copy_bm);
1628 1629
				if (error)
					return error;
1630 1631 1632 1633 1634

				chain_init(&ca, GFP_ATOMIC, PG_SAFE);
				memory_bm_position_reset(&orig_bm);
				restore_pblist = NULL;
				handle->buffer = get_buffer(&orig_bm, &ca);
A
Andrew Morton 已提交
1635
				handle->sync_read = 0;
1636 1637
				if (!handle->buffer)
					return -ENOMEM;
1638 1639
			}
		} else {
1640
			copy_last_highmem_page();
1641
			handle->buffer = get_buffer(&orig_bm, &ca);
1642 1643
			if (handle->buffer != buffer)
				handle->sync_read = 0;
1644
		}
1645
		handle->prev = handle->cur;
1646
	}
1647 1648 1649 1650 1651
	handle->buf_offset = handle->cur_offset;
	if (handle->cur_offset + count >= PAGE_SIZE) {
		count = PAGE_SIZE - handle->cur_offset;
		handle->cur_offset = 0;
		handle->cur++;
1652
	} else {
1653
		handle->cur_offset += count;
1654 1655 1656 1657 1658
	}
	handle->offset += count;
	return count;
}

1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676
/**
 *	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();
	/* Free only if we have loaded the image entirely */
	if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages) {
		memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
		free_highmem_data();
	}
}

1677 1678
int snapshot_image_loaded(struct snapshot_handle *handle)
{
1679
	return !(!nr_copy_pages || !last_highmem_page_copied() ||
1680 1681 1682
			handle->cur <= nr_meta_pages + nr_copy_pages);
}

1683 1684 1685 1686
#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)
1687
{
1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726
	void *kaddr1, *kaddr2;

	kaddr1 = kmap_atomic(p1, KM_USER0);
	kaddr2 = kmap_atomic(p2, KM_USER1);
	memcpy(buf, kaddr1, PAGE_SIZE);
	memcpy(kaddr1, kaddr2, PAGE_SIZE);
	memcpy(kaddr2, buf, PAGE_SIZE);
	kunmap_atomic(kaddr1, KM_USER0);
	kunmap_atomic(kaddr2, KM_USER1);
}

/**
 *	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;
1727
}
1728
#endif /* CONFIG_HIGHMEM */