/*
* linux/kernel/power/snapshot.c
*
* This file provides system snapshot/restore functionality for swsusp.
*
* Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>
* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
*
* This file is released under the GPLv2.
*
*/
#include <linux/version.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
#include "power.h"
static int swsusp_page_is_free(struct page *);
static void swsusp_set_page_forbidden(struct page *);
static void swsusp_unset_page_forbidden(struct page *);
/*
* Number of bytes to reserve for memory allocations made by device drivers
* from their ->freeze() and ->freeze_noirq() callbacks so that they don't
* cause image creation to fail (tunable via /sys/power/reserved_size).
*/
unsigned long reserved_size;
void __init hibernate_reserved_size_init(void)
{
reserved_size = SPARE_PAGES * PAGE_SIZE;
}
/*
* Preferred image size in bytes (tunable via /sys/power/image_size).
* When it is set to N, swsusp will do its best to ensure the image
* size will not exceed N bytes, but if that is impossible, it will
* try to create the smallest image possible.
*/
unsigned long image_size;
void __init hibernate_image_size_init(void)
{
image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE;
}
/* List of PBEs needed for restoring the pages that were allocated before
* the suspend and included in the suspend image, but have also been
* allocated by the "resume" kernel, so their contents cannot be written
* directly to their "original" page frames.
*/
struct pbe *restore_pblist;
/* Pointer to an auxiliary buffer (1 page) */
static void *buffer;
/**
* @safe_needed - on resume, for storing the PBE list and the image,
* we can only use memory pages that do not conflict with the pages
* used before suspend. The unsafe pages have PageNosaveFree set
* and we count them using unsafe_pages.
*
* Each allocated image page is marked as PageNosave and PageNosaveFree
* so that swsusp_free() can release it.
*/
#define PG_ANY 0
#define PG_SAFE 1
#define PG_UNSAFE_CLEAR 1
#define PG_UNSAFE_KEEP 0
static unsigned int allocated_unsafe_pages;
static void *get_image_page(gfp_t gfp_mask, int safe_needed)
{
void *res;
res = (void *)get_zeroed_page(gfp_mask);
if (safe_needed)
while (res && swsusp_page_is_free(virt_to_page(res))) {
/* The page is unsafe, mark it for swsusp_free() */
swsusp_set_page_forbidden(virt_to_page(res));
allocated_unsafe_pages++;
res = (void *)get_zeroed_page(gfp_mask);
}
if (res) {
swsusp_set_page_forbidden(virt_to_page(res));
swsusp_set_page_free(virt_to_page(res));
}
return res;
}
unsigned long get_safe_page(gfp_t gfp_mask)
{
return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
}
static struct page *alloc_image_page(gfp_t gfp_mask)
{
struct page *page;
page = alloc_page(gfp_mask);
if (page) {
swsusp_set_page_forbidden(page);
swsusp_set_page_free(page);
}
return page;
}
/**
* free_image_page - free page represented by @addr, allocated with
* get_image_page (page flags set by it must be cleared)
*/
static inline void free_image_page(void *addr, int clear_nosave_free)
{
struct page *page;
BUG_ON(!virt_addr_valid(addr));
page = virt_to_page(addr);
swsusp_unset_page_forbidden(page);
if (clear_nosave_free)
swsusp_unset_page_free(page);
__free_page(page);
}
/* struct linked_page is used to build chains of pages */
#define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *))
struct linked_page {
struct linked_page *next;
char data[LINKED_PAGE_DATA_SIZE];
} __attribute__((packed));
static inline void
free_list_of_pages(struct linked_page *list, int clear_page_nosave)
{
while (list) {
struct linked_page *lp = list->next;
free_image_page(list, clear_page_nosave);
list = lp;
}
}
/**
* struct chain_allocator is used for allocating small objects out of
* a linked list of pages called 'the chain'.
*
* The chain grows each time when there is no room for a new object in
* the current page. The allocated objects cannot be freed individually.
* It is only possible to free them all at once, by freeing the entire
* chain.
*
* NOTE: The chain allocator may be inefficient if the allocated objects
* are not much smaller than PAGE_SIZE.
*/
struct chain_allocator {
struct linked_page *chain; /* the chain */
unsigned int used_space; /* total size of objects allocated out
* of the current page
*/
gfp_t gfp_mask; /* mask for allocating pages */
int safe_needed; /* if set, only "safe" pages are allocated */
};
static void
chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed)
{
ca->chain = NULL;
ca->used_space = LINKED_PAGE_DATA_SIZE;
ca->gfp_mask = gfp_mask;
ca->safe_needed = safe_needed;
}
static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
{
void *ret;
if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
struct linked_page *lp;
lp = get_image_page(ca->gfp_mask, ca->safe_needed);
if (!lp)
return NULL;
lp->next = ca->chain;
ca->chain = lp;
ca->used_space = 0;
}
ret = ca->chain->data + ca->used_space;
ca->used_space += size;
return ret;
}
/**
* Data types related to memory bitmaps.
*
* Memory bitmap is a structure consiting of many linked lists of
* objects. The main list's elements are of type struct zone_bitmap
* and each of them corresonds to one zone. For each zone bitmap
* object there is a list of objects of type struct bm_block that
* represent each blocks of bitmap in which information is stored.
*
* struct memory_bitmap contains a pointer to the main list of zone
* bitmap objects, a struct bm_position used for browsing the bitmap,
* and a pointer to the list of pages used for allocating all of the
* zone bitmap objects and bitmap block objects.
*
* NOTE: It has to be possible to lay out the bitmap in memory
* using only allocations of order 0. Additionally, the bitmap is
* designed to work with arbitrary number of zones (this is over the
* top for now, but let's avoid making unnecessary assumptions ;-).
*
* struct zone_bitmap contains a pointer to a list of bitmap block
* objects and a pointer to the bitmap block object that has been
* most recently used for setting bits. Additionally, it contains the
* pfns that correspond to the start and end of the represented zone.
*
* struct bm_block contains a pointer to the memory page in which
* information is stored (in the form of a block of bitmap)
* It also contains the pfns that correspond to the start and end of
* the represented memory area.
*/
#define BM_END_OF_MAP (~0UL)
#define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE)
struct bm_block {
struct list_head hook; /* hook into a list of bitmap blocks */
unsigned long start_pfn; /* pfn represented by the first bit */
unsigned long end_pfn; /* pfn represented by the last bit plus 1 */
unsigned long *data; /* bitmap representing pages */
};
static inline unsigned long bm_block_bits(struct bm_block *bb)
{
return bb->end_pfn - bb->start_pfn;
}
/* strcut bm_position is used for browsing memory bitmaps */
struct bm_position {
struct bm_block *block;
int bit;
};
struct memory_bitmap {
struct list_head blocks; /* list of bitmap blocks */
struct linked_page *p_list; /* list of pages used to store zone
* bitmap objects and bitmap block
* objects
*/
struct bm_position cur; /* most recently used bit position */
};
/* Functions that operate on memory bitmaps */
static void memory_bm_position_reset(struct memory_bitmap *bm)
{
bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);
bm->cur.bit = 0;
}
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
/**
* create_bm_block_list - create a list of block bitmap objects
* @pages - number of pages to track
* @list - list to put the allocated blocks into
* @ca - chain allocator to be used for allocating memory
*/
static int create_bm_block_list(unsigned long pages,
struct list_head *list,
struct chain_allocator *ca)
{
unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
while (nr_blocks-- > 0) {
struct bm_block *bb;
bb = chain_alloc(ca, sizeof(struct bm_block));
if (!bb)
return -ENOMEM;
list_add(&bb->hook, list);
}
return 0;
}
struct mem_extent {
struct list_head hook;
unsigned long start;
unsigned long end;
};
/**
* free_mem_extents - free a list of memory extents
* @list - list of extents to empty
*/
static void free_mem_extents(struct list_head *list)
{
struct mem_extent *ext, *aux;
list_for_each_entry_safe(ext, aux, list, hook) {
list_del(&ext->hook);
kfree(ext);
}
}
/**
* create_mem_extents - create a list of memory extents representing
* contiguous ranges of PFNs
* @list - list to put the extents into
* @gfp_mask - mask to use for memory allocations
*/
static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
{
struct zone *zone;
INIT_LIST_HEAD(list);
for_each_populated_zone(zone) {
unsigned long zone_start, zone_end;
struct mem_extent *ext, *cur, *aux;
zone_start = zone->zone_start_pfn;
zone_end = zone->zone_start_pfn + zone->spanned_pages;
list_for_each_entry(ext, list, hook)
if (zone_start <= ext->end)
break;
if (&ext->hook == list || zone_end < ext->start) {
/* New extent is necessary */
struct mem_extent *new_ext;
new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
if (!new_ext) {
free_mem_extents(list);
return -ENOMEM;
}
new_ext->start = zone_start;
new_ext->end = zone_end;
list_add_tail(&new_ext->hook, &ext->hook);
continue;
}
/* Merge this zone's range of PFNs with the existing one */
if (zone_start < ext->start)
ext->start = zone_start;
if (zone_end > ext->end)
ext->end = zone_end;
/* More merging may be possible */
cur = ext;
list_for_each_entry_safe_continue(cur, aux, list, hook) {
if (zone_end < cur->start)
break;
if (zone_end < cur->end)
ext->end = cur->end;
list_del(&cur->hook);
kfree(cur);
}
}
return 0;
}
/**
* memory_bm_create - allocate memory for a memory bitmap
*/
static int
memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
{
struct chain_allocator ca;
struct list_head mem_extents;
struct mem_extent *ext;
int error;
chain_init(&ca, gfp_mask, safe_needed);
INIT_LIST_HEAD(&bm->blocks);
error = create_mem_extents(&mem_extents, gfp_mask);
if (error)
return error;
list_for_each_entry(ext, &mem_extents, hook) {
struct bm_block *bb;
unsigned long pfn = ext->start;
unsigned long pages = ext->end - ext->start;
bb = list_entry(bm->blocks.prev, struct bm_block, hook);
error = create_bm_block_list(pages, bm->blocks.prev, &ca);
if (error)
goto Error;
list_for_each_entry_continue(bb, &bm->blocks, hook) {
bb->data = get_image_page(gfp_mask, safe_needed);
if (!bb->data) {
error = -ENOMEM;
goto Error;
}
bb->start_pfn = pfn;
if (pages >= BM_BITS_PER_BLOCK) {
pfn += BM_BITS_PER_BLOCK;
pages -= BM_BITS_PER_BLOCK;
} else {
/* This is executed only once in the loop */
pfn += pages;
}
bb->end_pfn = pfn;
}
}
bm->p_list = ca.chain;
memory_bm_position_reset(bm);
Exit:
free_mem_extents(&mem_extents);
return error;
Error:
bm->p_list = ca.chain;
memory_bm_free(bm, PG_UNSAFE_CLEAR);
goto Exit;
}
/**
* memory_bm_free - free memory occupied by the memory bitmap @bm
*/
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
{
struct bm_block *bb;
list_for_each_entry(bb, &bm->blocks, hook)
if (bb->data)
free_image_page(bb->data, clear_nosave_free);
free_list_of_pages(bm->p_list, clear_nosave_free);
INIT_LIST_HEAD(&bm->blocks);
}
/**
* memory_bm_find_bit - find the bit in the bitmap @bm that corresponds
* to given pfn. The cur_zone_bm member of @bm and the cur_block member
* of @bm->cur_zone_bm are updated.
*/
static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
void **addr, unsigned int *bit_nr)
{
struct bm_block *bb;
/*
* Check if the pfn corresponds to the current bitmap block and find
* the block where it fits if this is not the case.
*/
bb = bm->cur.block;
if (pfn < bb->start_pfn)
list_for_each_entry_continue_reverse(bb, &bm->blocks, hook)
if (pfn >= bb->start_pfn)
break;
if (pfn >= bb->end_pfn)
list_for_each_entry_continue(bb, &bm->blocks, hook)
if (pfn >= bb->start_pfn && pfn < bb->end_pfn)
break;
if (&bb->hook == &bm->blocks)
return -EFAULT;
/* The block has been found */
bm->cur.block = bb;
pfn -= bb->start_pfn;
bm->cur.bit = pfn + 1;
*bit_nr = pfn;
*addr = bb->data;
return 0;
}
static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
{
void *addr;
unsigned int bit;
int error;
error = memory_bm_find_bit(bm, pfn, &addr, &bit);
BUG_ON(error);
set_bit(bit, addr);
}
static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
{
void *addr;
unsigned int bit;
int error;
error = memory_bm_find_bit(bm, pfn, &addr, &bit);
if (!error)
set_bit(bit, addr);
return error;
}
static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
{
void *addr;
unsigned int bit;
int error;
error = memory_bm_find_bit(bm, pfn, &addr, &bit);
BUG_ON(error);
clear_bit(bit, addr);
}
static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
{
void *addr;
unsigned int bit;
int error;
error = memory_bm_find_bit(bm, pfn, &addr, &bit);
BUG_ON(error);
return test_bit(bit, addr);
}
static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
{
void *addr;
unsigned int bit;
return !memory_bm_find_bit(bm, pfn, &addr, &bit);
}
/**
* memory_bm_next_pfn - find the pfn that corresponds to the next set bit
* in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is
* returned.
*
* It is required to run memory_bm_position_reset() before the first call to
* this function.
*/
static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
{
struct bm_block *bb;
int bit;
bb = bm->cur.block;
do {
bit = bm->cur.bit;
bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
if (bit < bm_block_bits(bb))
goto Return_pfn;
bb = list_entry(bb->hook.next, struct bm_block, hook);
bm->cur.block = bb;
bm->cur.bit = 0;
} while (&bb->hook != &bm->blocks);
memory_bm_position_reset(bm);
return BM_END_OF_MAP;
Return_pfn:
bm->cur.bit = bit + 1;
return bb->start_pfn + bit;
}
/**
* This structure represents a range of page frames the contents of which
* should not be saved during the suspend.
*/
struct nosave_region {
struct list_head list;
unsigned long start_pfn;
unsigned long end_pfn;
};
static LIST_HEAD(nosave_regions);
/**
* register_nosave_region - register a range of page frames the contents
* of which should not be saved during the suspend (to be used in the early
* initialization code)
*/
void __init
__register_nosave_region(unsigned long start_pfn, unsigned long end_pfn,
int use_kmalloc)
{
struct nosave_region *region;
if (start_pfn >= end_pfn)
return;
if (!list_empty(&nosave_regions)) {
/* Try to extend the previous region (they should be sorted) */
region = list_entry(nosave_regions.prev,
struct nosave_region, list);
if (region->end_pfn == start_pfn) {
region->end_pfn = end_pfn;
goto Report;
}
}
if (use_kmalloc) {
/* during init, this shouldn't fail */
region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
BUG_ON(!region);
} else
/* This allocation cannot fail */
region = alloc_bootmem(sizeof(struct nosave_region));
region->start_pfn = start_pfn;
region->end_pfn = end_pfn;
list_add_tail(®ion->list, &nosave_regions);
Report:
printk(KERN_INFO "PM: Registered nosave memory: %016lx - %016lx\n",
start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT);
}
/*
* Set bits in this map correspond to the page frames the contents of which
* should not be saved during the suspend.
*/
static struct memory_bitmap *forbidden_pages_map;
/* Set bits in this map correspond to free page frames. */
static struct memory_bitmap *free_pages_map;
/*
* Each page frame allocated for creating the image is marked by setting the
* corresponding bits in forbidden_pages_map and free_pages_map simultaneously
*/
void swsusp_set_page_free(struct page *page)
{
if (free_pages_map)
memory_bm_set_bit(free_pages_map, page_to_pfn(page));
}
static int swsusp_page_is_free(struct page *page)
{
return free_pages_map ?
memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
}
void swsusp_unset_page_free(struct page *page)
{
if (free_pages_map)
memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
}
static void swsusp_set_page_forbidden(struct page *page)
{
if (forbidden_pages_map)
memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
}
int swsusp_page_is_forbidden(struct page *page)
{
return forbidden_pages_map ?
memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
}
static void swsusp_unset_page_forbidden(struct page *page)
{
if (forbidden_pages_map)
memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
}
/**
* mark_nosave_pages - set bits corresponding to the page frames the
* contents of which should not be saved in a given bitmap.
*/
static void mark_nosave_pages(struct memory_bitmap *bm)
{
struct nosave_region *region;
if (list_empty(&nosave_regions))
return;
list_for_each_entry(region, &nosave_regions, list) {
unsigned long pfn;
pr_debug("PM: Marking nosave pages: [mem %#010llx-%#010llx]\n",
(unsigned long long) region->start_pfn << PAGE_SHIFT,
((unsigned long long) region->end_pfn << PAGE_SHIFT)
- 1);
for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
if (pfn_valid(pfn)) {
/*
* It is safe to ignore the result of
* mem_bm_set_bit_check() here, since we won't
* touch the PFNs for which the error is
* returned anyway.
*/
mem_bm_set_bit_check(bm, pfn);
}
}
}
/**
* create_basic_memory_bitmaps - create bitmaps needed for marking page
* frames that should not be saved and free page frames. The pointers
* forbidden_pages_map and free_pages_map are only modified if everything
* goes well, because we don't want the bits to be used before both bitmaps
* are set up.
*/
int create_basic_memory_bitmaps(void)
{
struct memory_bitmap *bm1, *bm2;
int error = 0;
BUG_ON(forbidden_pages_map || free_pages_map);
bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
if (!bm1)
return -ENOMEM;
error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
if (error)
goto Free_first_object;
bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
if (!bm2)
goto Free_first_bitmap;
error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
if (error)
goto Free_second_object;
forbidden_pages_map = bm1;
free_pages_map = bm2;
mark_nosave_pages(forbidden_pages_map);
pr_debug("PM: Basic memory bitmaps created\n");
return 0;
Free_second_object:
kfree(bm2);
Free_first_bitmap:
memory_bm_free(bm1, PG_UNSAFE_CLEAR);
Free_first_object:
kfree(bm1);
return -ENOMEM;
}
/**
* free_basic_memory_bitmaps - free memory bitmaps allocated by
* create_basic_memory_bitmaps(). The auxiliary pointers are necessary
* so that the bitmaps themselves are not referred to while they are being
* freed.
*/
void free_basic_memory_bitmaps(void)
{
struct memory_bitmap *bm1, *bm2;
BUG_ON(!(forbidden_pages_map && free_pages_map));
bm1 = forbidden_pages_map;
bm2 = free_pages_map;
forbidden_pages_map = NULL;
free_pages_map = NULL;
memory_bm_free(bm1, PG_UNSAFE_CLEAR);
kfree(bm1);
memory_bm_free(bm2, PG_UNSAFE_CLEAR);
kfree(bm2);
pr_debug("PM: Basic memory bitmaps freed\n");
}
/**
* snapshot_additional_pages - estimate the number of additional pages
* be needed for setting up the suspend image data structures for given
* zone (usually the returned value is greater than the exact number)
*/
unsigned int snapshot_additional_pages(struct zone *zone)
{
unsigned int res;
res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
res += DIV_ROUND_UP(res * sizeof(struct bm_block),
LINKED_PAGE_DATA_SIZE);
return 2 * res;
}
#ifdef CONFIG_HIGHMEM
/**
* count_free_highmem_pages - compute the total number of free highmem
* pages, system-wide.
*/
static unsigned int count_free_highmem_pages(void)
{
struct zone *zone;
unsigned int cnt = 0;
for_each_populated_zone(zone)
if (is_highmem(zone))
cnt += zone_page_state(zone, NR_FREE_PAGES);
return cnt;
}
/**
* saveable_highmem_page - Determine whether a highmem page should be
* included in the suspend image.
*
* We should save the page if it isn't Nosave or NosaveFree, or Reserved,
* and it isn't a part of a free chunk of pages.
*/
static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
{
struct page *page;
if (!pfn_valid(pfn))
return NULL;
page = pfn_to_page(pfn);
if (page_zone(page) != zone)
return NULL;
BUG_ON(!PageHighMem(page));
if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page) ||
PageReserved(page))
return NULL;
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->zone_start_pfn + zone->spanned_pages;
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (saveable_highmem_page(zone, pfn))
n++;
}
return n;
}
#else
static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
{
return NULL;
}
#endif /* CONFIG_HIGHMEM */
/**
* saveable_page - Determine whether a non-highmem page should be included
* in the suspend image.
*
* We should save the page if it isn't Nosave, and is not in the range
* of pages statically defined as 'unsaveable', and it isn't a part of
* a free chunk of pages.
*/
static struct page *saveable_page(struct zone *zone, unsigned long pfn)
{
struct page *page;
if (!pfn_valid(pfn))
return NULL;
page = pfn_to_page(pfn);
if (page_zone(page) != zone)
return NULL;
BUG_ON(PageHighMem(page));
if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
return NULL;
if (PageReserved(page)
&& (!kernel_page_present(page) || pfn_is_nosave(pfn)))
return NULL;
if (page_is_guard(page))
return NULL;
return page;
}
/**
* count_data_pages - compute the total number of saveable non-highmem
* pages.
*/
static unsigned int count_data_pages(void)
{
struct zone *zone;
unsigned long pfn, max_zone_pfn;
unsigned int n = 0;
for_each_populated_zone(zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (saveable_page(zone, pfn))
n++;
}
return n;
}
/* This is needed, because copy_page and memcpy are not usable for copying
* task structs.
*/
static inline void do_copy_page(long *dst, long *src)
{
int n;
for (n = PAGE_SIZE / sizeof(long); n; n--)
*dst++ = *src++;
}
/**
* safe_copy_page - check if the page we are going to copy is marked as
* present in the kernel page tables (this always is the case if
* CONFIG_DEBUG_PAGEALLOC is not set and in that case
* kernel_page_present() always returns 'true').
*/
static void safe_copy_page(void *dst, struct page *s_page)
{
if (kernel_page_present(s_page)) {
do_copy_page(dst, page_address(s_page));
} else {
kernel_map_pages(s_page, 1, 1);
do_copy_page(dst, page_address(s_page));
kernel_map_pages(s_page, 1, 0);
}
}
#ifdef CONFIG_HIGHMEM
static inline struct page *
page_is_saveable(struct zone *zone, unsigned long pfn)
{
return is_highmem(zone) ?
saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
}
static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
struct page *s_page, *d_page;
void *src, *dst;
s_page = pfn_to_page(src_pfn);
d_page = pfn_to_page(dst_pfn);
if (PageHighMem(s_page)) {
src = kmap_atomic(s_page);
dst = kmap_atomic(d_page);
do_copy_page(dst, src);
kunmap_atomic(dst);
kunmap_atomic(src);
} else {
if (PageHighMem(d_page)) {
/* Page pointed to by src may contain some kernel
* data modified by kmap_atomic()
*/
safe_copy_page(buffer, s_page);
dst = kmap_atomic(d_page);
copy_page(dst, buffer);
kunmap_atomic(dst);
} else {
safe_copy_page(page_address(d_page), s_page);
}
}
}
#else
#define page_is_saveable(zone, pfn) saveable_page(zone, pfn)
static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
safe_copy_page(page_address(pfn_to_page(dst_pfn)),
pfn_to_page(src_pfn));
}
#endif /* CONFIG_HIGHMEM */
static void
copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
{
struct zone *zone;
unsigned long pfn;
for_each_populated_zone(zone) {
unsigned long max_zone_pfn;
mark_free_pages(zone);
max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (page_is_saveable(zone, pfn))
memory_bm_set_bit(orig_bm, pfn);
}
memory_bm_position_reset(orig_bm);
memory_bm_position_reset(copy_bm);
for(;;) {
pfn = memory_bm_next_pfn(orig_bm);
if (unlikely(pfn == BM_END_OF_MAP))
break;
copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
}
}
/* Total number of image pages */
static unsigned int nr_copy_pages;
/* Number of pages needed for saving the original pfns of the image pages */
static unsigned int nr_meta_pages;
/*
* Numbers of normal and highmem page frames allocated for hibernation image
* before suspending devices.
*/
unsigned int alloc_normal, alloc_highmem;
/*
* Memory bitmap used for marking saveable pages (during hibernation) or
* hibernation image pages (during restore)
*/
static struct memory_bitmap orig_bm;
/*
* Memory bitmap used during hibernation for marking allocated page frames that
* will contain copies of saveable pages. During restore it is initially used
* for marking hibernation image pages, but then the set bits from it are
* duplicated in @orig_bm and it is released. On highmem systems it is next
* used for marking "safe" highmem pages, but it has to be reinitialized for
* this purpose.
*/
static struct memory_bitmap copy_bm;
/**
* swsusp_free - free pages allocated for the suspend.
*
* Suspend pages are alocated before the atomic copy is made, so we
* need to release them after the resume.
*/
void swsusp_free(void)
{
struct zone *zone;
unsigned long pfn, max_zone_pfn;
for_each_populated_zone(zone) {
max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);
if (swsusp_page_is_forbidden(page) &&
swsusp_page_is_free(page)) {
swsusp_unset_page_forbidden(page);
swsusp_unset_page_free(page);
__free_page(page);
}
}
}
nr_copy_pages = 0;
nr_meta_pages = 0;
restore_pblist = NULL;
buffer = NULL;
alloc_normal = 0;
alloc_highmem = 0;
}
/* Helper functions used for the shrinking of memory. */
#define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN)
/**
* preallocate_image_pages - Allocate a number of pages for hibernation image
* @nr_pages: Number of page frames to allocate.
* @mask: GFP flags to use for the allocation.
*
* Return value: Number of page frames actually allocated
*/
static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
{
unsigned long nr_alloc = 0;
while (nr_pages > 0) {
struct page *page;
page = alloc_image_page(mask);
if (!page)
break;
memory_bm_set_bit(©_bm, page_to_pfn(page));
if (PageHighMem(page))
alloc_highmem++;
else
alloc_normal++;
nr_pages--;
nr_alloc++;
}
return nr_alloc;
}
static unsigned long preallocate_image_memory(unsigned long nr_pages,
unsigned long avail_normal)
{
unsigned long alloc;
if (avail_normal <= alloc_normal)
return 0;
alloc = avail_normal - alloc_normal;
if (nr_pages < alloc)
alloc = nr_pages;
return preallocate_image_pages(alloc, GFP_IMAGE);
}
#ifdef CONFIG_HIGHMEM
static unsigned long preallocate_image_highmem(unsigned long nr_pages)
{
return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
}
/**
* __fraction - Compute (an approximation of) x * (multiplier / base)
*/
static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
{
x *= multiplier;
do_div(x, base);
return (unsigned long)x;
}
static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
unsigned long highmem,
unsigned long total)
{
unsigned long alloc = __fraction(nr_pages, highmem, total);
return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
}
#else /* CONFIG_HIGHMEM */
static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
{
return 0;
}
static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
unsigned long highmem,
unsigned long total)
{
return 0;
}
#endif /* CONFIG_HIGHMEM */
/**
* free_unnecessary_pages - Release preallocated pages not needed for the image
*/
static void free_unnecessary_pages(void)
{
unsigned long save, to_free_normal, to_free_highmem;
save = count_data_pages();
if (alloc_normal >= save) {
to_free_normal = alloc_normal - save;
save = 0;
} else {
to_free_normal = 0;
save -= alloc_normal;
}
save += count_highmem_pages();
if (alloc_highmem >= save) {
to_free_highmem = alloc_highmem - save;
} else {
to_free_highmem = 0;
save -= alloc_highmem;
if (to_free_normal > save)
to_free_normal -= save;
else
to_free_normal = 0;
}
memory_bm_position_reset(©_bm);
while (to_free_normal > 0 || to_free_highmem > 0) {
unsigned long pfn = memory_bm_next_pfn(©_bm);
struct page *page = pfn_to_page(pfn);
if (PageHighMem(page)) {
if (!to_free_highmem)
continue;
to_free_highmem--;
alloc_highmem--;
} else {
if (!to_free_normal)
continue;
to_free_normal--;
alloc_normal--;
}
memory_bm_clear_bit(©_bm, pfn);
swsusp_unset_page_forbidden(page);
swsusp_unset_page_free(page);
__free_page(page);
}
}
/**
* minimum_image_size - Estimate the minimum acceptable size of an image
* @saveable: Number of saveable pages in the system.
*
* We want to avoid attempting to free too much memory too hard, so estimate the
* minimum acceptable size of a hibernation image to use as the lower limit for
* preallocating memory.
*
* We assume that the minimum image size should be proportional to
*
* [number of saveable pages] - [number of pages that can be freed in theory]
*
* where the second term is the sum of (1) reclaimable slab pages, (2) active
* and (3) inactive anonymouns pages, (4) active and (5) inactive file pages,
* minus mapped file pages.
*/
static unsigned long minimum_image_size(unsigned long saveable)
{
unsigned long size;
size = global_page_state(NR_SLAB_RECLAIMABLE)
+ global_page_state(NR_ACTIVE_ANON)
+ global_page_state(NR_INACTIVE_ANON)
+ global_page_state(NR_ACTIVE_FILE)
+ global_page_state(NR_INACTIVE_FILE)
- global_page_state(NR_FILE_MAPPED);
return saveable <= size ? 0 : saveable - size;
}
/**
* hibernate_preallocate_memory - Preallocate memory for hibernation image
*
* To create a hibernation image it is necessary to make a copy of every page
* frame in use. We also need a number of page frames to be free during
* hibernation for allocations made while saving the image and for device
* drivers, in case they need to allocate memory from their hibernation
* callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
* estimate) and reserverd_size divided by PAGE_SIZE (which is tunable through
* /sys/power/reserved_size, respectively). To make this happen, we compute the
* total number of available page frames and allocate at least
*
* ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2
* + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
*
* of them, which corresponds to the maximum size of a hibernation image.
*
* If image_size is set below the number following from the above formula,
* the preallocation of memory is continued until the total number of saveable
* pages in the system is below the requested image size or the minimum
* acceptable image size returned by minimum_image_size(), whichever is greater.
*/
int hibernate_preallocate_memory(void)
{
struct zone *zone;
unsigned long saveable, size, max_size, count, highmem, pages = 0;
unsigned long alloc, save_highmem, pages_highmem, avail_normal;
struct timeval start, stop;
int error;
printk(KERN_INFO "PM: Preallocating image memory... ");
do_gettimeofday(&start);
error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
if (error)
goto err_out;
error = memory_bm_create(©_bm, GFP_IMAGE, PG_ANY);
if (error)
goto err_out;
alloc_normal = 0;
alloc_highmem = 0;
/* Count the number of saveable data pages. */
save_highmem = count_highmem_pages();
saveable = count_data_pages();
/*
* Compute the total number of page frames we can use (count) and the
* number of pages needed for image metadata (size).
*/
count = saveable;
saveable += save_highmem;
highmem = save_highmem;
size = 0;
for_each_populated_zone(zone) {
size += snapshot_additional_pages(zone);
if (is_highmem(zone))
highmem += zone_page_state(zone, NR_FREE_PAGES);
else
count += zone_page_state(zone, NR_FREE_PAGES);
}
avail_normal = count;
count += highmem;
count -= totalreserve_pages;
/* Add number of pages required for page keys (s390 only). */
size += page_key_additional_pages(saveable);
/* Compute the maximum number of saveable pages to leave in memory. */
max_size = (count - (size + PAGES_FOR_IO)) / 2
- 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
/* Compute the desired number of image pages specified by image_size. */
size = DIV_ROUND_UP(image_size, PAGE_SIZE);
if (size > max_size)
size = max_size;
/*
* If the desired number of image pages is at least as large as the
* current number of saveable pages in memory, allocate page frames for
* the image and we're done.
*/
if (size >= saveable) {
pages = preallocate_image_highmem(save_highmem);
pages += preallocate_image_memory(saveable - pages, avail_normal);
goto out;
}
/* Estimate the minimum size of the image. */
pages = minimum_image_size(saveable);
/*
* To avoid excessive pressure on the normal zone, leave room in it to
* accommodate an image of the minimum size (unless it's already too
* small, in which case don't preallocate pages from it at all).
*/
if (avail_normal > pages)
avail_normal -= pages;
else
avail_normal = 0;
if (size < pages)
size = min_t(unsigned long, pages, max_size);
/*
* Let the memory management subsystem know that we're going to need a
* large number of page frames to allocate and make it free some memory.
* NOTE: If this is not done, performance will be hurt badly in some
* test cases.
*/
shrink_all_memory(saveable - size);
/*
* The number of saveable pages in memory was too high, so apply some
* pressure to decrease it. First, make room for the largest possible
* image and fail if that doesn't work. Next, try to decrease the size
* of the image as much as indicated by 'size' using allocations from
* highmem and non-highmem zones separately.
*/
pages_highmem = preallocate_image_highmem(highmem / 2);
alloc = (count - max_size) - pages_highmem;
pages = preallocate_image_memory(alloc, avail_normal);
if (pages < alloc) {
/* We have exhausted non-highmem pages, try highmem. */
alloc -= pages;
pages += pages_highmem;
pages_highmem = preallocate_image_highmem(alloc);
if (pages_highmem < alloc)
goto err_out;
pages += pages_highmem;
/*
* size is the desired number of saveable pages to leave in
* memory, so try to preallocate (all memory - size) pages.
*/
alloc = (count - pages) - size;
pages += preallocate_image_highmem(alloc);
} else {
/*
* There are approximately max_size saveable pages at this point
* and we want to reduce this number down to size.
*/
alloc = max_size - size;
size = preallocate_highmem_fraction(alloc, highmem, count);
pages_highmem += size;
alloc -= size;
size = preallocate_image_memory(alloc, avail_normal);
pages_highmem += preallocate_image_highmem(alloc - size);
pages += pages_highmem + size;
}
/*
* We only need as many page frames for the image as there are saveable
* pages in memory, but we have allocated more. Release the excessive
* ones now.
*/
free_unnecessary_pages();
out:
do_gettimeofday(&stop);
printk(KERN_CONT "done (allocated %lu pages)\n", pages);
swsusp_show_speed(&start, &stop, pages, "Allocated");
return 0;
err_out:
printk(KERN_CONT "\n");
swsusp_free();
return -ENOMEM;
}
#ifdef CONFIG_HIGHMEM
/**
* count_pages_for_highmem - compute the number of non-highmem pages
* that will be necessary for creating copies of highmem pages.
*/
static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
{
unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
if (free_highmem >= nr_highmem)
nr_highmem = 0;
else
nr_highmem -= free_highmem;
return nr_highmem;
}
#else
static unsigned int
count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
#endif /* CONFIG_HIGHMEM */
/**
* enough_free_mem - Make sure we have enough free memory for the
* snapshot image.
*/
static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
{
struct zone *zone;
unsigned int free = alloc_normal;
for_each_populated_zone(zone)
if (!is_highmem(zone))
free += zone_page_state(zone, NR_FREE_PAGES);
nr_pages += count_pages_for_highmem(nr_highmem);
pr_debug("PM: Normal pages needed: %u + %u, available pages: %u\n",
nr_pages, PAGES_FOR_IO, free);
return free > nr_pages + PAGES_FOR_IO;
}
#ifdef CONFIG_HIGHMEM
/**
* get_highmem_buffer - if there are some highmem pages in the suspend
* image, we may need the buffer to copy them and/or load their data.
*/
static inline int get_highmem_buffer(int safe_needed)
{
buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
return buffer ? 0 : -ENOMEM;
}
/**
* alloc_highmem_image_pages - allocate some highmem pages for the image.
* Try to allocate as many pages as needed, but if the number of free
* highmem pages is lesser than that, allocate them all.
*/
static inline unsigned int
alloc_highmem_pages(struct memory_bitmap *bm, unsigned int nr_highmem)
{
unsigned int to_alloc = count_free_highmem_pages();
if (to_alloc > nr_highmem)
to_alloc = nr_highmem;
nr_highmem -= to_alloc;
while (to_alloc-- > 0) {
struct page *page;
page = alloc_image_page(__GFP_HIGHMEM);
memory_bm_set_bit(bm, page_to_pfn(page));
}
return nr_highmem;
}
#else
static inline int get_highmem_buffer(int safe_needed) { return 0; }
static inline unsigned int
alloc_highmem_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }
#endif /* CONFIG_HIGHMEM */
/**
* swsusp_alloc - allocate memory for the suspend image
*
* We first try to allocate as many highmem pages as there are
* saveable highmem pages in the system. If that fails, we allocate
* non-highmem pages for the copies of the remaining highmem ones.
*
* In this approach it is likely that the copies of highmem pages will
* also be located in the high memory, because of the way in which
* copy_data_pages() works.
*/
static int
swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
unsigned int nr_pages, unsigned int nr_highmem)
{
if (nr_highmem > 0) {
if (get_highmem_buffer(PG_ANY))
goto err_out;
if (nr_highmem > alloc_highmem) {
nr_highmem -= alloc_highmem;
nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
}
}
if (nr_pages > alloc_normal) {
nr_pages -= alloc_normal;
while (nr_pages-- > 0) {
struct page *page;
page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
if (!page)
goto err_out;
memory_bm_set_bit(copy_bm, page_to_pfn(page));
}
}
return 0;
err_out:
swsusp_free();
return -ENOMEM;
}
asmlinkage int swsusp_save(void)
{
unsigned int nr_pages, nr_highmem;
printk(KERN_INFO "PM: Creating hibernation image:\n");
drain_local_pages(NULL);
nr_pages = count_data_pages();
nr_highmem = count_highmem_pages();
printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem);
if (!enough_free_mem(nr_pages, nr_highmem)) {
printk(KERN_ERR "PM: Not enough free memory\n");
return -ENOMEM;
}
if (swsusp_alloc(&orig_bm, ©_bm, nr_pages, nr_highmem)) {
printk(KERN_ERR "PM: Memory allocation failed\n");
return -ENOMEM;
}
/* During allocating of suspend pagedir, new cold pages may appear.
* Kill them.
*/
drain_local_pages(NULL);
copy_data_pages(©_bm, &orig_bm);
/*
* End of critical section. From now on, we can write to memory,
* but we should not touch disk. This specially means we must _not_
* touch swap space! Except we must write out our image of course.
*/
nr_pages += nr_highmem;
nr_copy_pages = nr_pages;
nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
printk(KERN_INFO "PM: Hibernation image created (%d pages copied)\n",
nr_pages);
return 0;
}
#ifndef CONFIG_ARCH_HIBERNATION_HEADER
static int init_header_complete(struct swsusp_info *info)
{
memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
info->version_code = LINUX_VERSION_CODE;
return 0;
}
static char *check_image_kernel(struct swsusp_info *info)
{
if (info->version_code != LINUX_VERSION_CODE)
return "kernel version";
if (strcmp(info->uts.sysname,init_utsname()->sysname))
return "system type";
if (strcmp(info->uts.release,init_utsname()->release))
return "kernel release";
if (strcmp(info->uts.version,init_utsname()->version))
return "version";
if (strcmp(info->uts.machine,init_utsname()->machine))
return "machine";
return NULL;
}
#endif /* CONFIG_ARCH_HIBERNATION_HEADER */
unsigned long snapshot_get_image_size(void)
{
return nr_copy_pages + nr_meta_pages + 1;
}
static int init_header(struct swsusp_info *info)
{
memset(info, 0, sizeof(struct swsusp_info));
info->num_physpages = num_physpages;
info->image_pages = nr_copy_pages;
info->pages = snapshot_get_image_size();
info->size = info->pages;
info->size <<= PAGE_SHIFT;
return init_header_complete(info);
}
/**
* pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
* are stored in the array @buf[] (1 page at a time)
*/
static inline void
pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
buf[j] = memory_bm_next_pfn(bm);
if (unlikely(buf[j] == BM_END_OF_MAP))
break;
/* Save page key for data page (s390 only). */
page_key_read(buf + j);
}
}
/**
* snapshot_read_next - used for reading the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* On success the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory
* location computed by the data_of() macro.
*
* The function returns 0 to indicate the end of data stream condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_read_next(struct snapshot_handle *handle)
{
if (handle->cur > nr_meta_pages + nr_copy_pages)
return 0;
if (!buffer) {
/* This makes the buffer be freed by swsusp_free() */
buffer = get_image_page(GFP_ATOMIC, PG_ANY);
if (!buffer)
return -ENOMEM;
}
if (!handle->cur) {
int error;
error = init_header((struct swsusp_info *)buffer);
if (error)
return error;
handle->buffer = buffer;
memory_bm_position_reset(&orig_bm);
memory_bm_position_reset(©_bm);
} else if (handle->cur <= nr_meta_pages) {
clear_page(buffer);
pack_pfns(buffer, &orig_bm);
} else {
struct page *page;
page = pfn_to_page(memory_bm_next_pfn(©_bm));
if (PageHighMem(page)) {
/* Highmem pages are copied to the buffer,
* because we can't return with a kmapped
* highmem page (we may not be called again).
*/
void *kaddr;
kaddr = kmap_atomic(page);
copy_page(buffer, kaddr);
kunmap_atomic(kaddr);
handle->buffer = buffer;
} else {
handle->buffer = page_address(page);
}
}
handle->cur++;
return PAGE_SIZE;
}
/**
* mark_unsafe_pages - mark the pages that cannot be used for storing
* the image during resume, because they conflict with the pages that
* had been used before suspend
*/
static int mark_unsafe_pages(struct memory_bitmap *bm)
{
struct zone *zone;
unsigned long pfn, max_zone_pfn;
/* Clear page flags */
for_each_populated_zone(zone) {
max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (pfn_valid(pfn))
swsusp_unset_page_free(pfn_to_page(pfn));
}
/* Mark pages that correspond to the "original" pfns as "unsafe" */
memory_bm_position_reset(bm);
do {
pfn = memory_bm_next_pfn(bm);
if (likely(pfn != BM_END_OF_MAP)) {
if (likely(pfn_valid(pfn)))
swsusp_set_page_free(pfn_to_page(pfn));
else
return -EFAULT;
}
} while (pfn != BM_END_OF_MAP);
allocated_unsafe_pages = 0;
return 0;
}
static void
duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
{
unsigned long pfn;
memory_bm_position_reset(src);
pfn = memory_bm_next_pfn(src);
while (pfn != BM_END_OF_MAP) {
memory_bm_set_bit(dst, pfn);
pfn = memory_bm_next_pfn(src);
}
}
static int check_header(struct swsusp_info *info)
{
char *reason;
reason = check_image_kernel(info);
if (!reason && info->num_physpages != num_physpages)
reason = "memory size";
if (reason) {
printk(KERN_ERR "PM: Image mismatch: %s\n", reason);
return -EPERM;
}
return 0;
}
/**
* load header - check the image header and copy data from it
*/
static int
load_header(struct swsusp_info *info)
{
int error;
restore_pblist = NULL;
error = check_header(info);
if (!error) {
nr_copy_pages = info->image_pages;
nr_meta_pages = info->pages - info->image_pages - 1;
}
return error;
}
/**
* unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
* the corresponding bit in the memory bitmap @bm
*/
static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
if (unlikely(buf[j] == BM_END_OF_MAP))
break;
/* Extract and buffer page key for data page (s390 only). */
page_key_memorize(buf + j);
if (memory_bm_pfn_present(bm, buf[j]))
memory_bm_set_bit(bm, buf[j]);
else
return -EFAULT;
}
return 0;
}
/* List of "safe" pages that may be used to store data loaded from the suspend
* image
*/
static struct linked_page *safe_pages_list;
#ifdef CONFIG_HIGHMEM
/* struct highmem_pbe is used for creating the list of highmem pages that
* should be restored atomically during the resume from disk, because the page
* frames they have occupied before the suspend are in use.
*/
struct highmem_pbe {
struct page *copy_page; /* data is here now */
struct page *orig_page; /* data was here before the suspend */
struct highmem_pbe *next;
};
/* List of highmem PBEs needed for restoring the highmem pages that were
* allocated before the suspend and included in the suspend image, but have
* also been allocated by the "resume" kernel, so their contents cannot be
* written directly to their "original" page frames.
*/
static struct highmem_pbe *highmem_pblist;
/**
* count_highmem_image_pages - compute the number of highmem pages in the
* suspend image. The bits in the memory bitmap @bm that correspond to the
* image pages are assumed to be set.
*/
static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
{
unsigned long pfn;
unsigned int cnt = 0;
memory_bm_position_reset(bm);
pfn = memory_bm_next_pfn(bm);
while (pfn != BM_END_OF_MAP) {
if (PageHighMem(pfn_to_page(pfn)))
cnt++;
pfn = memory_bm_next_pfn(bm);
}
return cnt;
}
/**
* prepare_highmem_image - try to allocate as many highmem pages as
* there are highmem image pages (@nr_highmem_p points to the variable
* containing the number of highmem image pages). The pages that are
* "safe" (ie. will not be overwritten when the suspend image is
* restored) have the corresponding bits set in @bm (it must be
* unitialized).
*
* NOTE: This function should not be called if there are no highmem
* image pages.
*/
static unsigned int safe_highmem_pages;
static struct memory_bitmap *safe_highmem_bm;
static int
prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
{
unsigned int to_alloc;
if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
return -ENOMEM;
if (get_highmem_buffer(PG_SAFE))
return -ENOMEM;
to_alloc = count_free_highmem_pages();
if (to_alloc > *nr_highmem_p)
to_alloc = *nr_highmem_p;
else
*nr_highmem_p = to_alloc;
safe_highmem_pages = 0;
while (to_alloc-- > 0) {
struct page *page;
page = alloc_page(__GFP_HIGHMEM);
if (!swsusp_page_is_free(page)) {
/* The page is "safe", set its bit the bitmap */
memory_bm_set_bit(bm, page_to_pfn(page));
safe_highmem_pages++;
}
/* Mark the page as allocated */
swsusp_set_page_forbidden(page);
swsusp_set_page_free(page);
}
memory_bm_position_reset(bm);
safe_highmem_bm = bm;
return 0;
}
/**
* get_highmem_page_buffer - for given highmem image page find the buffer
* that suspend_write_next() should set for its caller to write to.
*
* If the page is to be saved to its "original" page frame or a copy of
* the page is to be made in the highmem, @buffer is returned. Otherwise,
* the copy of the page is to be made in normal memory, so the address of
* the copy is returned.
*
* If @buffer is returned, the caller of suspend_write_next() will write
* the page's contents to @buffer, so they will have to be copied to the
* right location on the next call to suspend_write_next() and it is done
* with the help of copy_last_highmem_page(). For this purpose, if
* @buffer is returned, @last_highmem page is set to the page to which
* the data will have to be copied from @buffer.
*/
static struct page *last_highmem_page;
static void *
get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
{
struct highmem_pbe *pbe;
void *kaddr;
if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
/* We have allocated the "original" page frame and we can
* use it directly to store the loaded page.
*/
last_highmem_page = page;
return buffer;
}
/* The "original" page frame has not been allocated and we have to
* use a "safe" page frame to store the loaded page.
*/
pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
if (!pbe) {
swsusp_free();
return ERR_PTR(-ENOMEM);
}
pbe->orig_page = page;
if (safe_highmem_pages > 0) {
struct page *tmp;
/* Copy of the page will be stored in high memory */
kaddr = buffer;
tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
safe_highmem_pages--;
last_highmem_page = tmp;
pbe->copy_page = tmp;
} else {
/* Copy of the page will be stored in normal memory */
kaddr = safe_pages_list;
safe_pages_list = safe_pages_list->next;
pbe->copy_page = virt_to_page(kaddr);
}
pbe->next = highmem_pblist;
highmem_pblist = pbe;
return kaddr;
}
/**
* copy_last_highmem_page - copy the contents of a highmem image from
* @buffer, where the caller of snapshot_write_next() has place them,
* to the right location represented by @last_highmem_page .
*/
static void copy_last_highmem_page(void)
{
if (last_highmem_page) {
void *dst;
dst = kmap_atomic(last_highmem_page);
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 inline int get_safe_write_buffer(void) { return 0; }
static unsigned int
count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
static inline int
prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
{
return 0;
}
static inline void *
get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
{
return ERR_PTR(-EINVAL);
}
static inline void copy_last_highmem_page(void) {}
static inline int last_highmem_page_copied(void) { return 1; }
static inline void free_highmem_data(void) {}
#endif /* CONFIG_HIGHMEM */
/**
* prepare_image - use the memory bitmap @bm to mark the pages that will
* be overwritten in the process of restoring the system memory state
* from the suspend image ("unsafe" pages) and allocate memory for the
* image.
*
* The idea is to allocate a new memory bitmap first and then allocate
* as many pages as needed for the image data, but not to assign these
* pages to specific tasks initially. Instead, we just mark them as
* allocated and create a lists of "safe" pages that will be used
* later. On systems with high memory a list of "safe" highmem pages is
* also created.
*/
#define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
static int
prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
{
unsigned int nr_pages, nr_highmem;
struct linked_page *sp_list, *lp;
int error;
/* If there is no highmem, the buffer will not be necessary */
free_image_page(buffer, PG_UNSAFE_CLEAR);
buffer = NULL;
nr_highmem = count_highmem_image_pages(bm);
error = mark_unsafe_pages(bm);
if (error)
goto Free;
error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
if (error)
goto Free;
duplicate_memory_bitmap(new_bm, bm);
memory_bm_free(bm, PG_UNSAFE_KEEP);
if (nr_highmem > 0) {
error = prepare_highmem_image(bm, &nr_highmem);
if (error)
goto Free;
}
/* Reserve some safe pages for potential later use.
*
* NOTE: This way we make sure there will be enough safe pages for the
* chain_alloc() in get_buffer(). It is a bit wasteful, but
* nr_copy_pages cannot be greater than 50% of the memory anyway.
*/
sp_list = NULL;
/* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
while (nr_pages > 0) {
lp = get_image_page(GFP_ATOMIC, PG_SAFE);
if (!lp) {
error = -ENOMEM;
goto Free;
}
lp->next = sp_list;
sp_list = lp;
nr_pages--;
}
/* Preallocate memory for the image */
safe_pages_list = NULL;
nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
while (nr_pages > 0) {
lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
if (!lp) {
error = -ENOMEM;
goto Free;
}
if (!swsusp_page_is_free(virt_to_page(lp))) {
/* The page is "safe", add it to the list */
lp->next = safe_pages_list;
safe_pages_list = lp;
}
/* Mark the page as allocated */
swsusp_set_page_forbidden(virt_to_page(lp));
swsusp_set_page_free(virt_to_page(lp));
nr_pages--;
}
/* Free the reserved safe pages so that chain_alloc() can use them */
while (sp_list) {
lp = sp_list->next;
free_image_page(sp_list, PG_UNSAFE_CLEAR);
sp_list = lp;
}
return 0;
Free:
swsusp_free();
return error;
}
/**
* get_buffer - compute the address that snapshot_write_next() should
* set for its caller to write to.
*/
static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
{
struct pbe *pbe;
struct page *page;
unsigned long pfn = memory_bm_next_pfn(bm);
if (pfn == BM_END_OF_MAP)
return ERR_PTR(-EFAULT);
page = pfn_to_page(pfn);
if (PageHighMem(page))
return get_highmem_page_buffer(page, ca);
if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
/* We have allocated the "original" page frame and we can
* use it directly to store the loaded page.
*/
return page_address(page);
/* The "original" page frame has not been allocated and we have to
* use a "safe" page frame to store the loaded page.
*/
pbe = chain_alloc(ca, sizeof(struct pbe));
if (!pbe) {
swsusp_free();
return ERR_PTR(-ENOMEM);
}
pbe->orig_address = page_address(page);
pbe->address = safe_pages_list;
safe_pages_list = safe_pages_list->next;
pbe->next = restore_pblist;
restore_pblist = pbe;
return pbe->address;
}
/**
* snapshot_write_next - used for writing the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* On success the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory
* location computed by the data_of() macro.
*
* The function returns 0 to indicate the "end of file" condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_write_next(struct snapshot_handle *handle)
{
static struct chain_allocator ca;
int error = 0;
/* Check if we have already loaded the entire image */
if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
return 0;
handle->sync_read = 1;
if (!handle->cur) {
if (!buffer)
/* This makes the buffer be freed by swsusp_free() */
buffer = get_image_page(GFP_ATOMIC, PG_ANY);
if (!buffer)
return -ENOMEM;
handle->buffer = buffer;
} else if (handle->cur == 1) {
error = load_header(buffer);
if (error)
return error;
error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
if (error)
return error;
/* Allocate buffer for page keys. */
error = page_key_alloc(nr_copy_pages);
if (error)
return error;
} else if (handle->cur <= nr_meta_pages + 1) {
error = unpack_orig_pfns(buffer, ©_bm);
if (error)
return error;
if (handle->cur == nr_meta_pages + 1) {
error = prepare_image(&orig_bm, ©_bm);
if (error)
return error;
chain_init(&ca, GFP_ATOMIC, PG_SAFE);
memory_bm_position_reset(&orig_bm);
restore_pblist = NULL;
handle->buffer = get_buffer(&orig_bm, &ca);
handle->sync_read = 0;
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
}
} else {
copy_last_highmem_page();
/* Restore page key for data page (s390 only). */
page_key_write(handle->buffer);
handle->buffer = get_buffer(&orig_bm, &ca);
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
if (handle->buffer != buffer)
handle->sync_read = 0;
}
handle->cur++;
return PAGE_SIZE;
}
/**
* snapshot_write_finalize - must be called after the last call to
* snapshot_write_next() in case the last page in the image happens
* to be a highmem page and its contents should be stored in the
* highmem. Additionally, it releases the memory that will not be
* used any more.
*/
void snapshot_write_finalize(struct snapshot_handle *handle)
{
copy_last_highmem_page();
/* Restore page key for data page (s390 only). */
page_key_write(handle->buffer);
page_key_free();
/* Free only if we have loaded the image entirely */
if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
free_highmem_data();
}
}
int snapshot_image_loaded(struct snapshot_handle *handle)
{
return !(!nr_copy_pages || !last_highmem_page_copied() ||
handle->cur <= nr_meta_pages + nr_copy_pages);
}
#ifdef CONFIG_HIGHMEM
/* Assumes that @buf is ready and points to a "safe" page */
static inline void
swap_two_pages_data(struct page *p1, struct page *p2, void *buf)
{
void *kaddr1, *kaddr2;
kaddr1 = kmap_atomic(p1);
kaddr2 = kmap_atomic(p2);
copy_page(buf, kaddr1);
copy_page(kaddr1, kaddr2);
copy_page(kaddr2, buf);
kunmap_atomic(kaddr2);
kunmap_atomic(kaddr1);
}
/**
* restore_highmem - for each highmem page that was allocated before
* the suspend and included in the suspend image, and also has been
* allocated by the "resume" kernel swap its current (ie. "before
* resume") contents with the previous (ie. "before suspend") one.
*
* If the resume eventually fails, we can call this function once
* again and restore the "before resume" highmem state.
*/
int restore_highmem(void)
{
struct highmem_pbe *pbe = highmem_pblist;
void *buf;
if (!pbe)
return 0;
buf = get_image_page(GFP_ATOMIC, PG_SAFE);
if (!buf)
return -ENOMEM;
while (pbe) {
swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
pbe = pbe->next;
}
free_image_page(buf, PG_UNSAFE_CLEAR);
return 0;
}
#endif /* CONFIG_HIGHMEM */