// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/power/snapshot.c
*
* This file provides system snapshot/restore functionality for swsusp.
*
* Copyright (C) 1998-2005 Pavel Machek <[email protected]>
* Copyright (C) 2006 Rafael J. Wysocki <[email protected]>
*/
#define pr_fmt(fmt) "PM: hibernation: " fmt
#include <linux/version.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/nmi.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/compiler.h>
#include <linux/ktime.h>
#include <linux/set_memory.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
#include "power.h"
#if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_ARCH_HAS_SET_MEMORY)
static bool hibernate_restore_protection;
static bool hibernate_restore_protection_active;
void enable_restore_image_protection(void)
{
hibernate_restore_protection = true;
}
static inline void hibernate_restore_protection_begin(void)
{
hibernate_restore_protection_active = hibernate_restore_protection;
}
static inline void hibernate_restore_protection_end(void)
{
hibernate_restore_protection_active = false;
}
static inline int __must_check hibernate_restore_protect_page(void *page_address)
{
if (hibernate_restore_protection_active)
return set_memory_ro((unsigned long)page_address, 1);
return 0;
}
static inline int hibernate_restore_unprotect_page(void *page_address)
{
if (hibernate_restore_protection_active)
return set_memory_rw((unsigned long)page_address, 1);
return 0;
}
#else
static inline void hibernate_restore_protection_begin(void) {}
static inline void hibernate_restore_protection_end(void) {}
static inline int __must_check hibernate_restore_protect_page(void *page_address) {return 0; }
static inline int hibernate_restore_unprotect_page(void *page_address) {return 0; }
#endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */
/*
* The calls to set_direct_map_*() should not fail because remapping a page
* here means that we only update protection bits in an existing PTE.
* It is still worth to have a warning here if something changes and this
* will no longer be the case.
*/
static inline void hibernate_map_page(struct page *page)
{
if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
int ret = set_direct_map_default_noflush(page);
if (ret)
pr_warn_once("Failed to remap page\n");
} else {
debug_pagealloc_map_pages(page, 1);
}
}
static inline void hibernate_unmap_page(struct page *page)
{
if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
unsigned long addr = (unsigned long)page_address(page);
int ret = set_direct_map_invalid_noflush(page);
if (ret)
pr_warn_once("Failed to remap page\n");
flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
} else {
debug_pagealloc_unmap_pages(page, 1);
}
}
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;
/* 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];
} __packed;
/*
* List of "safe" pages (ie. pages that were not used by the image kernel
* before hibernation) that may be used as temporary storage for image kernel
* memory contents.
*/
static struct linked_page *safe_pages_list;
/* Pointer to an auxiliary buffer (1 page) */
static void *buffer;
#define PG_ANY 0
#define PG_SAFE 1
#define PG_UNSAFE_CLEAR 1
#define PG_UNSAFE_KEEP 0
static unsigned int allocated_unsafe_pages;
/**
* get_image_page - Allocate a page for a hibernation image.
* @gfp_mask: GFP mask for the allocation.
* @safe_needed: Get pages that were not used before hibernation (restore only)
*
* During image restoration, for storing the PBE list and the image data, we can
* only use memory pages that do not conflict with the pages used before
* hibernation. The "unsafe" pages have PageNosaveFree set and we count them
* using allocated_unsafe_pages.
*
* Each allocated image page is marked as PageNosave and PageNosaveFree so that
* swsusp_free() can release it.
*/
static void *get_image_page(gfp_t gfp_mask, int safe_needed)
{
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;
}
static void *__get_safe_page(gfp_t gfp_mask)
{
if (safe_pages_list) {
void *ret = safe_pages_list;
safe_pages_list = safe_pages_list->next;
memset(ret, 0, PAGE_SIZE);
return ret;
}
return get_image_page(gfp_mask, PG_SAFE);
}
unsigned long get_safe_page(gfp_t gfp_mask)
{
return (unsigned long)__get_safe_page(gfp_mask);
}
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;
}
static void recycle_safe_page(void *page_address)
{
struct linked_page *lp = page_address;
lp->next = safe_pages_list;
safe_pages_list = lp;
}
/**
* free_image_page - Free a page allocated for hibernation image.
* @addr: Address of the page to free.
* @clear_nosave_free: If set, clear the PageNosaveFree bit for the page.
*
* The page to free should have been allocated by get_image_page() (page flags
* set by it are affected).
*/
static inline void free_image_page(void *addr, int clear_nosave_free)
{
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);
}
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 = ca->safe_needed ? __get_safe_page(ca->gfp_mask) :
get_image_page(ca->gfp_mask, PG_ANY);
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 consisting of many linked lists of
* objects. The main list's elements are of type struct zone_bitmap
* and each of them corresponds to one zone. For each zone bitmap
* object there is a list of objects of type struct bm_block that
* represent each blocks of bitmap in which information is stored.
*
* struct memory_bitmap contains a pointer to the main list of zone
* bitmap objects, a struct bm_position used for browsing the bitmap,
* and a pointer to the list of pages used for allocating all of the
* zone bitmap objects and bitmap block objects.
*
* NOTE: It has to be possible to lay out the bitmap in memory
* using only allocations of order 0. Additionally, the bitmap is
* designed to work with arbitrary number of zones (this is over the
* top for now, but let's avoid making unnecessary assumptions ;-).
*
* struct zone_bitmap contains a pointer to a list of bitmap block
* objects and a pointer to the bitmap block object that has been
* most recently used for setting bits. Additionally, it contains the
* PFNs that correspond to the start and end of the represented zone.
*
* struct bm_block contains a pointer to the memory page in which
* information is stored (in the form of a block of bitmap)
* It also contains the pfns that correspond to the start and end of
* the represented memory area.
*
* The memory bitmap is organized as a radix tree to guarantee fast random
* access to the bits. There is one radix tree for each zone (as returned
* from create_mem_extents).
*
* One radix tree is represented by one struct mem_zone_bm_rtree. There are
* two linked lists for the nodes of the tree, one for the inner nodes and
* one for the leave nodes. The linked leave nodes are used for fast linear
* access of the memory bitmap.
*
* The struct rtree_node represents one node of the radix tree.
*/
#define BM_END_OF_MAP (~0UL)
#define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE)
#define BM_BLOCK_SHIFT (PAGE_SHIFT + 3)
#define BM_BLOCK_MASK ((1UL << BM_BLOCK_SHIFT) - 1)
/*
* struct rtree_node is a wrapper struct to link the nodes
* of the rtree together for easy linear iteration over
* bits and easy freeing
*/
struct rtree_node {
struct list_head list;
unsigned long *data;
};
/*
* struct mem_zone_bm_rtree represents a bitmap used for one
* populated memory zone.
*/
struct mem_zone_bm_rtree {
struct list_head list; /* Link Zones together */
struct list_head nodes; /* Radix Tree inner nodes */
struct list_head leaves; /* Radix Tree leaves */
unsigned long start_pfn; /* Zone start page frame */
unsigned long end_pfn; /* Zone end page frame + 1 */
struct rtree_node *rtree; /* Radix Tree Root */
int levels; /* Number of Radix Tree Levels */
unsigned int blocks; /* Number of Bitmap Blocks */
};
/* struct bm_position is used for browsing memory bitmaps */
struct bm_position {
struct mem_zone_bm_rtree *zone;
struct rtree_node *node;
unsigned long node_pfn;
unsigned long cur_pfn;
int node_bit;
};
struct memory_bitmap {
struct list_head zones;
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 */
#define BM_ENTRIES_PER_LEVEL (PAGE_SIZE / sizeof(unsigned long))
#if BITS_PER_LONG == 32
#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 2)
#else
#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 3)
#endif
#define BM_RTREE_LEVEL_MASK ((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
/**
* alloc_rtree_node - Allocate a new node and add it to the radix tree.
* @gfp_mask: GFP mask for the allocation.
* @safe_needed: Get pages not used before hibernation (restore only)
* @ca: Pointer to a linked list of pages ("a chain") to allocate from
* @list: Radix Tree node to add.
*
* This function is used to allocate inner nodes as well as the
* leave nodes of the radix tree. It also adds the node to the
* corresponding linked list passed in by the *list parameter.
*/
static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
struct chain_allocator *ca,
struct list_head *list)
{
struct rtree_node *node;
node = chain_alloc(ca, sizeof(struct rtree_node));
if (!node)
return NULL;
node->data = get_image_page(gfp_mask, safe_needed);
if (!node->data)
return NULL;
list_add_tail(&node->list, list);
return node;
}
/**
* add_rtree_block - Add a new leave node to the radix tree.
*
* The leave nodes need to be allocated in order to keep the leaves
* linked list in order. This is guaranteed by the zone->blocks
* counter.
*/
static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
int safe_needed, struct chain_allocator *ca)
{
struct rtree_node *node, *block, **dst;
unsigned int levels_needed, block_nr;
int i;
block_nr = zone->blocks;
levels_needed = 0;
/* How many levels do we need for this block nr? */
while (block_nr) {
levels_needed += 1;
block_nr >>= BM_RTREE_LEVEL_SHIFT;
}
/* Make sure the rtree has enough levels */
for (i = zone->levels; i < levels_needed; i++) {
node = alloc_rtree_node(gfp_mask, safe_needed, ca,
&zone->nodes);
if (!node)
return -ENOMEM;
node->data[0] = (unsigned long)zone->rtree;
zone->rtree = node;
zone->levels += 1;
}
/* Allocate new block */
block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves);
if (!block)
return -ENOMEM;
/* Now walk the rtree to insert the block */
node = zone->rtree;
dst = &zone->rtree;
block_nr = zone->blocks;
for (i = zone->levels; i > 0; i--) {
int index;
if (!node) {
node = alloc_rtree_node(gfp_mask, safe_needed, ca,
&zone->nodes);
if (!node)
return -ENOMEM;
*dst = node;
}
index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
index &= BM_RTREE_LEVEL_MASK;
dst = (struct rtree_node **)&((*dst)->data[index]);
node = *dst;
}
zone->blocks += 1;
*dst = block;
return 0;
}
static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
int clear_nosave_free);
/**
* create_zone_bm_rtree - Create a radix tree for one zone.
*
* Allocated the mem_zone_bm_rtree structure and initializes it.
* This function also allocated and builds the radix tree for the
* zone.
*/
static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask,
int safe_needed,
struct chain_allocator *ca,
unsigned long start,
unsigned long end)
{
struct mem_zone_bm_rtree *zone;
unsigned int i, nr_blocks;
unsigned long pages;
pages = end - start;
zone = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree));
if (!zone)
return NULL;
INIT_LIST_HEAD(&zone->nodes);
INIT_LIST_HEAD(&zone->leaves);
zone->start_pfn = start;
zone->end_pfn = end;
nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
for (i = 0; i < nr_blocks; i++) {
if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
return NULL;
}
}
return zone;
}
/**
* free_zone_bm_rtree - Free the memory of the radix tree.
*
* Free all node pages of the radix tree. The mem_zone_bm_rtree
* structure itself is not freed here nor are the rtree_node
* structs.
*/
static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
int clear_nosave_free)
{
struct rtree_node *node;
list_for_each_entry(node, &zone->nodes, list)
free_image_page(node->data, clear_nosave_free);
list_for_each_entry(node, &zone->leaves, list)
free_image_page(node->data, clear_nosave_free);
}
static void memory_bm_position_reset(struct memory_bitmap *bm)
{
bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
list);
bm->cur.node = list_entry(bm->cur.zone->leaves.next,
struct rtree_node, list);
bm->cur.node_pfn = 0;
bm->cur.cur_pfn = BM_END_OF_MAP;
bm->cur.node_bit = 0;
}
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
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 free.
*/
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.
* @list: List to put the extents into.
* @gfp_mask: Mask to use for memory allocations.
*
* The extents represent contiguous ranges of PFNs.
*/
static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
{
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_end_pfn(zone);
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->zones);
error = create_mem_extents(&mem_extents, gfp_mask);
if (error)
return error;
list_for_each_entry(ext, &mem_extents, hook) {
struct mem_zone_bm_rtree *zone;
zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca,
ext->start, ext->end);
if (!zone) {
error = -ENOMEM;
goto Error;
}
list_add_tail(&zone->list, &bm->zones);
}
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: Memory bitmap.
*/
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
{
struct mem_zone_bm_rtree *zone;
list_for_each_entry(zone, &bm->zones, list)
free_zone_bm_rtree(zone, clear_nosave_free);
free_list_of_pages(bm->p_list, clear_nosave_free);
INIT_LIST_HEAD(&bm->zones);
}
/**
* memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap.
*
* Find the bit in memory bitmap @bm that corresponds to the given PFN.
* The cur.zone, cur.block and cur.node_pfn members of @bm are updated.
*
* Walk the radix tree to find the page containing the bit that represents @pfn
* and return the position of the bit in @addr and @bit_nr.
*/
static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
void **addr, unsigned int *bit_nr)
{
struct mem_zone_bm_rtree *curr, *zone;
struct rtree_node *node;
int i, block_nr;
zone = bm->cur.zone;
if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
goto zone_found;
zone = NULL;
/* Find the right zone */
list_for_each_entry(curr, &bm->zones, list) {
if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
zone = curr;
break;
}
}
if (!zone)
return -EFAULT;
zone_found:
/*
* We have found the zone. Now walk the radix tree to find the leaf node
* for our PFN.
*/
/*
* If the zone we wish to scan is the current zone and the
* pfn falls into the current node then we do not need to walk
* the tree.
*/
node = bm->cur.node;
if (zone == bm->cur.zone &&
((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
goto node_found;
node = zone->rtree;
block_nr = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
for (i = zone->levels; i > 0; i--) {
int index;
index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
index &= BM_RTREE_LEVEL_MASK;
BUG_ON(node->data[index] == 0);
node = (struct rtree_node *)node->data[index];
}
node_found:
/* Update last position */
bm->cur.zone = zone;
bm->cur.node = node;
bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;
bm->cur.cur_pfn = pfn;
/* Set return values */
*addr = node->data;
*bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;
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 void memory_bm_clear_current(struct memory_bitmap *bm)
{
int bit;
bit = max(bm->cur.node_bit - 1, 0);
clear_bit(bit, bm->cur.node->data);
}
static unsigned long memory_bm_get_current(struct memory_bitmap *bm)
{
return bm->cur.cur_pfn;
}
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);
}
/*
* rtree_next_node - Jump to the next leaf node.
*
* Set the position to the beginning of the next node in the
* memory bitmap. This is either the next node in the current
* zone's radix tree or the first node in the radix tree of the
* next zone.
*
* Return true if there is a next node, false otherwise.
*/
static bool rtree_next_node(struct memory_bitmap *bm)
{
if (!list_is_last(&bm->cur.node->list, &bm->cur.zone->leaves)) {
bm->cur.node = list_entry(bm->cur.node->list.next,
struct rtree_node, list);
bm->cur.node_pfn += BM_BITS_PER_BLOCK;
bm->cur.node_bit = 0;
touch_softlockup_watchdog();
return true;
}
/* No more nodes, goto next zone */
if (!list_is_last(&bm->cur.zone->list, &bm->zones)) {
bm->cur.zone = list_entry(bm->cur.zone->list.next,
struct mem_zone_bm_rtree, list);
bm->cur.node = list_entry(bm->cur.zone->leaves.next,
struct rtree_node, list);
bm->cur.node_pfn = 0;
bm->cur.node_bit = 0;
return true;
}
/* No more zones */
return false;
}
/**
* memory_bm_next_pfn - Find the next set bit in a memory bitmap.
* @bm: Memory bitmap.
*
* Starting from the last returned position this function searches for the next
* set bit in @bm and returns the PFN represented by it. If no more bits are
* set, BM_END_OF_MAP is returned.
*
* It is required to run memory_bm_position_reset() before the first call to
* this function for the given memory bitmap.
*/
static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
{
unsigned long bits, pfn, pages;
int bit;
do {
pages = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
bits = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
bit = find_next_bit(bm->cur.node->data, bits,
bm->cur.node_bit);
if (bit < bits) {
pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
bm->cur.node_bit = bit + 1;
bm->cur.cur_pfn = pfn;
return pfn;
}
} while (rtree_next_node(bm));
bm->cur.cur_pfn = BM_END_OF_MAP;
return BM_END_OF_MAP;
}
/*
* This structure represents a range of page frames the contents of which
* should not be saved during hibernation.
*/
struct nosave_region {
struct list_head list;
unsigned long start_pfn;
unsigned long end_pfn;
};
static LIST_HEAD(nosave_regions);
static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone)
{
struct rtree_node *node;
list_for_each_entry(node, &zone->nodes, list)
recycle_safe_page(node->data);
list_for_each_entry(node, &zone->leaves, list)
recycle_safe_page(node->data);
}
static void memory_bm_recycle(struct memory_bitmap *bm)
{
struct mem_zone_bm_rtree *zone;
struct linked_page *p_list;
list_for_each_entry(zone, &bm->zones, list)
recycle_zone_bm_rtree(zone);
p_list = bm->p_list;
while (p_list) {
struct linked_page *lp = p_list;
p_list = lp->next;
recycle_safe_page(lp);
}
}
/**
* register_nosave_region - Register a region of unsaveable memory.
*
* Register a range of page frames the contents of which should not be saved
* during hibernation (to be used in the early initialization code).
*/
void __init register_nosave_region(unsigned long start_pfn, unsigned long end_pfn)
{
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;
}
}
/* This allocation cannot fail */
region = memblock_alloc(sizeof(struct nosave_region),
SMP_CACHE_BYTES);
if (!region)
panic("%s: Failed to allocate %zu bytes\n", __func__,
sizeof(struct nosave_region));
region->start_pfn = start_pfn;
region->end_pfn = end_pfn;
list_add_tail(®ion->list, &nosave_regions);
Report:
pr_info("Registered nosave memory: [mem %#010llx-%#010llx]\n",
(unsigned long long) start_pfn << PAGE_SHIFT,
((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
}
/*
* 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 - Mark pages that should not be saved.
* @bm: Memory bitmap.
*
* Set the bits in @bm that correspond to the page frames the contents of which
* should not be saved.
*/
static void mark_nosave_pages(struct memory_bitmap *bm)
{
struct nosave_region *region;
if (list_empty(&nosave_regions))
return;
list_for_each_entry(region, &nosave_regions, list) {
unsigned long pfn;
pr_debug("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 to hold basic page information.
*
* Create bitmaps needed for marking page frames that should not be saved and
* free page frames. The forbidden_pages_map and free_pages_map pointers are
* only modified if everything goes well, because we don't want the bits to be
* touched before both bitmaps are set up.
*/
int create_basic_memory_bitmaps(void)
{
struct memory_bitmap *bm1, *bm2;
int error;
if (forbidden_pages_map && free_pages_map)
return 0;
else
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("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 holding basic information.
*
* Free memory bitmaps allocated by create_basic_memory_bitmaps(). The
* auxiliary pointers are necessary so that the bitmaps themselves are not
* referred to while they are being freed.
*/
void free_basic_memory_bitmaps(void)
{
struct memory_bitmap *bm1, *bm2;
if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
return;
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("Basic memory bitmaps freed\n");
}
static void clear_or_poison_free_page(struct page *page)
{
if (page_poisoning_enabled_static())
__kernel_poison_pages(page, 1);
else if (want_init_on_free())
clear_highpage(page);
}
void clear_or_poison_free_pages(void)
{
struct memory_bitmap *bm = free_pages_map;
unsigned long pfn;
if (WARN_ON(!(free_pages_map)))
return;
if (page_poisoning_enabled() || want_init_on_free()) {
memory_bm_position_reset(bm);
pfn = memory_bm_next_pfn(bm);
while (pfn != BM_END_OF_MAP) {
if (pfn_valid(pfn))
clear_or_poison_free_page(pfn_to_page(pfn));
pfn = memory_bm_next_pfn(bm);
}
memory_bm_position_reset(bm);
pr_info("free pages cleared after restore\n");
}
}
/**
* snapshot_additional_pages - Estimate the number of extra pages needed.
* @zone: Memory zone to carry out the computation for.
*
* Estimate the number of additional pages needed for setting up a hibernation
* image data structures for @zone (usually, the returned value is greater than
* the exact number).
*/
unsigned int snapshot_additional_pages(struct zone *zone)
{
unsigned int rtree, nodes;
rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
LINKED_PAGE_DATA_SIZE);
while (nodes > 1) {
nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
rtree += nodes;
}
return 2 * rtree;
}
/*
* Touch the watchdog for every WD_PAGE_COUNT pages.
*/
#define WD_PAGE_COUNT (128*1024)
static void mark_free_pages(struct zone *zone)
{
unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
unsigned long flags;
unsigned int order, t;
struct page *page;
if (zone_is_empty(zone))
return;
spin_lock_irqsave(&zone->lock, flags);
max_zone_pfn = zone_end_pfn(zone);
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (pfn_valid(pfn)) {
page = pfn_to_page(pfn);
if (!--page_count) {
touch_nmi_watchdog();
page_count = WD_PAGE_COUNT;
}
if (page_zone(page) != zone)
continue;
if (!swsusp_page_is_forbidden(page))
swsusp_unset_page_free(page);
}
for_each_migratetype_order(order, t) {
list_for_each_entry(page,
&zone->free_area[order].free_list[t], buddy_list) {
unsigned long i;
pfn = page_to_pfn(page);
for (i = 0; i < (1UL << order); i++) {
if (!--page_count) {
touch_nmi_watchdog();
page_count = WD_PAGE_COUNT;
}
swsusp_set_page_free(pfn_to_page(pfn + i));
}
}
}
spin_unlock_irqrestore(&zone->lock, flags);
}
#ifdef CONFIG_HIGHMEM
/**
* count_free_highmem_pages - Compute the total number of free highmem pages.
*
* The returned number is system-wide.
*/
static unsigned int count_free_highmem_pages(void)
{
struct zone *zone;
unsigned int cnt = 0;
for_each_populated_zone(zone)
if (is_highmem(zone))
cnt += zone_page_state(zone, NR_FREE_PAGES);
return cnt;
}
/**
* saveable_highmem_page - Check if a highmem page is saveable.
*
* Determine whether a highmem page should be included in a hibernation image.
*
* We should save the page if it isn't Nosave or NosaveFree, or Reserved,
* and it isn't part of a free chunk of pages.
*/
static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
{
struct page *page;
if (!pfn_valid(pfn))
return NULL;
page = pfn_to_online_page(pfn);
if (!page || page_zone(page) != zone)
return NULL;
BUG_ON(!PageHighMem(page));
if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
return NULL;
if (PageReserved(page) || PageOffline(page))
return NULL;
if (page_is_guard(page))
return NULL;
return page;
}
/**
* count_highmem_pages - Compute the total number of saveable highmem pages.
*/
static unsigned int count_highmem_pages(void)
{
struct zone *zone;
unsigned int n = 0;
for_each_populated_zone(zone) {
unsigned long pfn, max_zone_pfn;
if (!is_highmem(zone))
continue;
mark_free_pages(zone);
max_zone_pfn = zone_end_pfn(zone);
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (saveable_highmem_page(zone, pfn))
n++;
}
return n;
}
#endif /* CONFIG_HIGHMEM */
/**
* saveable_page - Check if the given page is saveable.
*
* Determine whether a non-highmem page should be included in a hibernation
* image.
*
* We should save the page if it isn't Nosave, and is not in the range
* of pages statically defined as 'unsaveable', and it isn't part of
* a free chunk of pages.
*/
static struct page *saveable_page(struct zone *zone, unsigned long pfn)
{
struct page *page;
if (!pfn_valid(pfn))
return NULL;
page = pfn_to_online_page(pfn);
if (!page || page_zone(page) != zone)
return NULL;
BUG_ON(PageHighMem(page));
if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
return NULL;
if (PageOffline(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_end_pfn(zone);
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. Returns true if the page was filled with only zeros,
* otherwise false.
*/
static inline bool do_copy_page(long *dst, long *src)
{
long z = 0;
int n;
for (n = PAGE_SIZE / sizeof(long); n; n--) {
z |= *src;
*dst++ = *src++;
}
return !z;
}
/**
* safe_copy_page - Copy a page in a safe way.
*
* Check if the page we are going to copy is marked as present in the kernel
* page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
* CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
* always returns 'true'. Returns true if the page was entirely composed of
* zeros, otherwise it will return false.
*/
static bool safe_copy_page(void *dst, struct page *s_page)
{
bool zeros_only;
if (kernel_page_present(s_page)) {
zeros_only = do_copy_page(dst, page_address(s_page));
} else {
hibernate_map_page(s_page);
zeros_only = do_copy_page(dst, page_address(s_page));
hibernate_unmap_page(s_page);
}
return zeros_only;
}
#ifdef CONFIG_HIGHMEM
static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn)
{
return is_highmem(zone) ?
saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
}
static bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
struct page *s_page, *d_page;
void *src, *dst;
bool zeros_only;
s_page = pfn_to_page(src_pfn);
d_page = pfn_to_page(dst_pfn);
if (PageHighMem(s_page)) {
src = kmap_local_page(s_page);
dst = kmap_local_page(d_page);
zeros_only = do_copy_page(dst, src);
kunmap_local(dst);
kunmap_local(src);
} else {
if (PageHighMem(d_page)) {
/*
* The page pointed to by src may contain some kernel
* data modified by kmap_atomic()
*/
zeros_only = safe_copy_page(buffer, s_page);
dst = kmap_local_page(d_page);
copy_page(dst, buffer);
kunmap_local(dst);
} else {
zeros_only = safe_copy_page(page_address(d_page), s_page);
}
}
return zeros_only;
}
#else
#define page_is_saveable(zone, pfn) saveable_page(zone, pfn)
static inline int copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
return safe_copy_page(page_address(pfn_to_page(dst_pfn)),
pfn_to_page(src_pfn));
}
#endif /* CONFIG_HIGHMEM */
/*
* Copy data pages will copy all pages into pages pulled from the copy_bm.
* If a page was entirely filled with zeros it will be marked in the zero_bm.
*
* Returns the number of pages copied.
*/
static unsigned long copy_data_pages(struct memory_bitmap *copy_bm,
struct memory_bitmap *orig_bm,
struct memory_bitmap *zero_bm)
{
unsigned long copied_pages = 0;
struct zone *zone;
unsigned long pfn, copy_pfn;
for_each_populated_zone(zone) {
unsigned long max_zone_pfn;
mark_free_pages(zone);
max_zone_pfn = zone_end_pfn(zone);
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);
copy_pfn = memory_bm_next_pfn(copy_bm);
for(;;) {
pfn = memory_bm_next_pfn(orig_bm);
if (unlikely(pfn == BM_END_OF_MAP))
break;
if (copy_data_page(copy_pfn, pfn)) {
memory_bm_set_bit(zero_bm, pfn);
/* Use this copy_pfn for a page that is not full of zeros */
continue;
}
copied_pages++;
copy_pfn = memory_bm_next_pfn(copy_bm);
}
return copied_pages;
}
/* Total number of image pages */
static unsigned int nr_copy_pages;
/* Number of pages needed for saving the original pfns of the image pages */
static unsigned int nr_meta_pages;
/* Number of zero pages */
static unsigned int nr_zero_pages;
/*
* Numbers of normal and highmem page frames allocated for hibernation image
* before suspending devices.
*/
static unsigned int alloc_normal, alloc_highmem;
/*
* Memory bitmap used for marking saveable pages (during hibernation) or
* hibernation image pages (during restore)
*/
static struct memory_bitmap orig_bm;
/*
* Memory bitmap used during hibernation for marking allocated page frames that
* will contain copies of saveable pages. During restore it is initially used
* for marking hibernation image pages, but then the set bits from it are
* duplicated in @orig_bm and it is released. On highmem systems it is next
* used for marking "safe" highmem pages, but it has to be reinitialized for
* this purpose.
*/
static struct memory_bitmap copy_bm;
/* Memory bitmap which tracks which saveable pages were zero filled. */
static struct memory_bitmap zero_bm;
/**
* swsusp_free - Free pages allocated for hibernation image.
*
* Image pages are allocated before snapshot creation, so they need to be
* released after resume.
*/
void swsusp_free(void)
{
unsigned long fb_pfn, fr_pfn;
if (!forbidden_pages_map || !free_pages_map)
goto out;
memory_bm_position_reset(forbidden_pages_map);
memory_bm_position_reset(free_pages_map);
loop:
fr_pfn = memory_bm_next_pfn(free_pages_map);
fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
/*
* Find the next bit set in both bitmaps. This is guaranteed to
* terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
*/
do {
if (fb_pfn < fr_pfn)
fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
if (fr_pfn < fb_pfn)
fr_pfn = memory_bm_next_pfn(free_pages_map);
} while (fb_pfn != fr_pfn);
if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) {
struct page *page = pfn_to_page(fr_pfn);
memory_bm_clear_current(forbidden_pages_map);
memory_bm_clear_current(free_pages_map);
hibernate_restore_unprotect_page(page_address(page));
__free_page(page);
goto loop;
}
out:
nr_copy_pages = 0;
nr_meta_pages = 0;
nr_zero_pages = 0;
restore_pblist = NULL;
buffer = NULL;
alloc_normal = 0;
alloc_highmem = 0;
hibernate_restore_protection_end();
}
/* 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)
{
return div64_u64(x * multiplier, base);
}
static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
unsigned long highmem,
unsigned long total)
{
unsigned long alloc = __fraction(nr_pages, highmem, total);
return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
}
#else /* CONFIG_HIGHMEM */
static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
{
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 unsigned long free_unnecessary_pages(void)
{
unsigned long save, to_free_normal, to_free_highmem, free;
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;
}
free = to_free_normal + to_free_highmem;
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);
}
return free;
}
/**
* minimum_image_size - Estimate the minimum acceptable size of an image.
* @saveable: Number of saveable pages in the system.
*
* We want to avoid attempting to free too much memory too hard, so estimate the
* minimum acceptable size of a hibernation image to use as the lower limit for
* preallocating memory.
*
* We assume that the minimum image size should be proportional to
*
* [number of saveable pages] - [number of pages that can be freed in theory]
*
* where the second term is the sum of (1) reclaimable slab pages, (2) active
* and (3) inactive anonymous pages, (4) active and (5) inactive file pages.
*/
static unsigned long minimum_image_size(unsigned long saveable)
{
unsigned long size;
size = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B)
+ global_node_page_state(NR_ACTIVE_ANON)
+ global_node_page_state(NR_INACTIVE_ANON)
+ global_node_page_state(NR_ACTIVE_FILE)
+ global_node_page_state(NR_INACTIVE_FILE);
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 reserved_size divided by PAGE_SIZE (which is tunable through
* /sys/power/reserved_size, respectively). To make this happen, we compute the
* total number of available page frames and allocate at least
*
* ([page frames total] - PAGES_FOR_IO - [metadata pages]) / 2
* - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
*
* of them, which corresponds to the maximum size of a hibernation image.
*
* If image_size is set below the number following from the above formula,
* the preallocation of memory is continued until the total number of saveable
* pages in the system is below the requested image size or the minimum
* acceptable image size returned by minimum_image_size(), whichever is greater.
*/
int hibernate_preallocate_memory(void)
{
struct zone *zone;
unsigned long saveable, size, max_size, count, highmem, pages = 0;
unsigned long alloc, save_highmem, pages_highmem, avail_normal;
ktime_t start, stop;
int error;
pr_info("Preallocating image memory\n");
start = ktime_get();
error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
if (error) {
pr_err("Cannot allocate original bitmap\n");
goto err_out;
}
error = memory_bm_create(©_bm, GFP_IMAGE, PG_ANY);
if (error) {
pr_err("Cannot allocate copy bitmap\n");
goto err_out;
}
error = memory_bm_create(&zero_bm, GFP_IMAGE, PG_ANY);
if (error) {
pr_err("Cannot allocate zero bitmap\n");
goto err_out;
}
alloc_normal = 0;
alloc_highmem = 0;
nr_zero_pages = 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;
/* 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;
if (alloc > pages_highmem)
alloc -= pages_highmem;
else
alloc = 0;
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) {
pr_err("Image allocation is %lu pages short\n",
alloc - pages_highmem);
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.
*/
pages -= free_unnecessary_pages();
out:
stop = ktime_get();
pr_info("Allocated %lu pages for snapshot\n", pages);
swsusp_show_speed(start, stop, pages, "Allocated");
return 0;
err_out:
swsusp_free();
return -ENOMEM;
}
#ifdef CONFIG_HIGHMEM
/**
* count_pages_for_highmem - Count non-highmem pages needed for copying highmem.
*
* Compute the number of non-highmem pages that will be necessary for creating
* copies of highmem pages.
*/
static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
{
unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
if (free_highmem >= nr_highmem)
nr_highmem = 0;
else
nr_highmem -= free_highmem;
return nr_highmem;
}
#else
static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
#endif /* CONFIG_HIGHMEM */
/**
* enough_free_mem - Check if there is enough free memory for the image.
*/
static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
{
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("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 - Allocate a buffer for highmem pages.
*
* If there are some highmem pages in the hibernation image, we may need a
* buffer to copy them and/or load their data.
*/
static inline int get_highmem_buffer(int safe_needed)
{
buffer = get_image_page(GFP_ATOMIC, safe_needed);
return buffer ? 0 : -ENOMEM;
}
/**
* alloc_highmem_pages - Allocate some highmem pages for the image.
*
* Try to allocate as many pages as needed, but if the number of free highmem
* pages is less than that, allocate them all.
*/
static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
unsigned int nr_highmem)
{
unsigned int to_alloc = count_free_highmem_pages();
if (to_alloc > nr_highmem)
to_alloc = nr_highmem;
nr_highmem -= to_alloc;
while (to_alloc-- > 0) {
struct page *page;
page = alloc_image_page(__GFP_HIGHMEM|__GFP_KSWAPD_RECLAIM);
memory_bm_set_bit(bm, page_to_pfn(page));
}
return nr_highmem;
}
#else
static inline int get_highmem_buffer(int safe_needed) { 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 hibernation image.
*
* We first try to allocate as many highmem pages as there are
* saveable highmem pages in the system. If that fails, we allocate
* non-highmem pages for the copies of the remaining highmem ones.
*
* In this approach it is likely that the copies of highmem pages will
* also be located in the high memory, because of the way in which
* copy_data_pages() works.
*/
static int swsusp_alloc(struct memory_bitmap *copy_bm,
unsigned int nr_pages, unsigned int nr_highmem)
{
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);
if (!page)
goto err_out;
memory_bm_set_bit(copy_bm, page_to_pfn(page));
}
}
return 0;
err_out:
swsusp_free();
return -ENOMEM;
}
asmlinkage __visible int swsusp_save(void)
{
unsigned int nr_pages, nr_highmem;
pr_info("Creating image:\n");
drain_local_pages(NULL);
nr_pages = count_data_pages();
nr_highmem = count_highmem_pages();
pr_info("Need to copy %u pages\n", nr_pages + nr_highmem);
if (!enough_free_mem(nr_pages, nr_highmem)) {
pr_err("Not enough free memory\n");
return -ENOMEM;
}
if (swsusp_alloc(©_bm, nr_pages, nr_highmem)) {
pr_err("Memory allocation failed\n");
return -ENOMEM;
}
/*
* During allocating of suspend pagedir, new cold pages may appear.
* Kill them.
*/
drain_local_pages(NULL);
nr_copy_pages = copy_data_pages(©_bm, &orig_bm, &zero_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;
/* We don't actually copy the zero pages */
nr_zero_pages = nr_pages - nr_copy_pages;
nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
pr_info("Image created (%d pages copied, %d zero pages)\n", nr_copy_pages, nr_zero_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 const char *check_image_kernel(struct swsusp_info *info)
{
if (info->version_code != LINUX_VERSION_CODE)
return "kernel version";
if (strcmp(info->uts.sysname,init_utsname()->sysname))
return "system type";
if (strcmp(info->uts.release,init_utsname()->release))
return "kernel release";
if (strcmp(info->uts.version,init_utsname()->version))
return "version";
if (strcmp(info->uts.machine,init_utsname()->machine))
return "machine";
return NULL;
}
#endif /* CONFIG_ARCH_HIBERNATION_HEADER */
unsigned long snapshot_get_image_size(void)
{
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 = get_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);
}
#define ENCODED_PFN_ZERO_FLAG ((unsigned long)1 << (BITS_PER_LONG - 1))
#define ENCODED_PFN_MASK (~ENCODED_PFN_ZERO_FLAG)
/**
* pack_pfns - Prepare PFNs for saving.
* @bm: Memory bitmap.
* @buf: Memory buffer to store the PFNs in.
* @zero_bm: Memory bitmap containing PFNs of zero pages.
*
* PFNs corresponding to set bits in @bm are stored in the area of memory
* pointed to by @buf (1 page at a time). Pages which were filled with only
* zeros will have the highest bit set in the packed format to distinguish
* them from PFNs which will be contained in the image file.
*/
static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm,
struct memory_bitmap *zero_bm)
{
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;
if (memory_bm_test_bit(zero_bm, buf[j]))
buf[j] |= ENCODED_PFN_ZERO_FLAG;
}
}
/**
* snapshot_read_next - Get the address to read the next image page from.
* @handle: Snapshot handle to be used for the reading.
*
* On the first call, @handle should point to a zeroed snapshot_handle
* structure. The structure gets populated then and a pointer to it should be
* passed to this function every next time.
*
* On success, the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory
* location computed by the data_of() macro.
*
* The function returns 0 to indicate the end of the data stream condition,
* and negative numbers are returned on errors. If that happens, the structure
* pointed to by @handle is not updated and should not be used any more.
*/
int snapshot_read_next(struct snapshot_handle *handle)
{
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, &zero_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;
}
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);
}
}
/**
* mark_unsafe_pages - Mark pages that were used before hibernation.
*
* Mark the pages that cannot be used for storing the image during restoration,
* because they conflict with the pages that had been used before hibernation.
*/
static void mark_unsafe_pages(struct memory_bitmap *bm)
{
unsigned long pfn;
/* Clear the "free"/"unsafe" bit for all PFNs */
memory_bm_position_reset(free_pages_map);
pfn = memory_bm_next_pfn(free_pages_map);
while (pfn != BM_END_OF_MAP) {
memory_bm_clear_current(free_pages_map);
pfn = memory_bm_next_pfn(free_pages_map);
}
/* Mark pages that correspond to the "original" PFNs as "unsafe" */
duplicate_memory_bitmap(free_pages_map, bm);
allocated_unsafe_pages = 0;
}
static int check_header(struct swsusp_info *info)
{
const char *reason;
reason = check_image_kernel(info);
if (!reason && info->num_physpages != get_num_physpages())
reason = "memory size";
if (reason) {
pr_err("Image mismatch: %s\n", reason);
return -EPERM;
}
return 0;
}
/**
* load_header - Check the image header and copy the 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 - Set bits corresponding to given PFNs in a memory bitmap.
* @bm: Memory bitmap.
* @buf: Area of memory containing the PFNs.
* @zero_bm: Memory bitmap with the zero PFNs marked.
*
* For each element of the array pointed to by @buf (1 page at a time), set the
* corresponding bit in @bm. If the page was originally populated with only
* zeros then a corresponding bit will also be set in @zero_bm.
*/
static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm,
struct memory_bitmap *zero_bm)
{
unsigned long decoded_pfn;
bool zero;
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
if (unlikely(buf[j] == BM_END_OF_MAP))
break;
zero = !!(buf[j] & ENCODED_PFN_ZERO_FLAG);
decoded_pfn = buf[j] & ENCODED_PFN_MASK;
if (pfn_valid(decoded_pfn) && memory_bm_pfn_present(bm, decoded_pfn)) {
memory_bm_set_bit(bm, decoded_pfn);
if (zero) {
memory_bm_set_bit(zero_bm, decoded_pfn);
nr_zero_pages++;
}
} else {
if (!pfn_valid(decoded_pfn))
pr_err(FW_BUG "Memory map mismatch at 0x%llx after hibernation\n",
(unsigned long long)PFN_PHYS(decoded_pfn));
return -EFAULT;
}
}
return 0;
}
#ifdef CONFIG_HIGHMEM
/*
* struct highmem_pbe is used for creating the list of highmem pages that
* should be restored atomically during the resume from disk, because the page
* frames they have occupied before the suspend are in use.
*/
struct highmem_pbe {
struct page *copy_page; /* data is here now */
struct page *orig_page; /* data was here before the suspend */
struct highmem_pbe *next;
};
/*
* List of highmem PBEs needed for restoring the highmem pages that were
* allocated before the suspend and included in the suspend image, but have
* also been allocated by the "resume" kernel, so their contents cannot be
* written directly to their "original" page frames.
*/
static struct highmem_pbe *highmem_pblist;
/**
* count_highmem_image_pages - Compute the number of highmem pages in the image.
* @bm: Memory bitmap.
*
* The bits in @bm that correspond to image pages are assumed to be set.
*/
static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
{
unsigned long pfn;
unsigned int cnt = 0;
memory_bm_position_reset(bm);
pfn = memory_bm_next_pfn(bm);
while (pfn != BM_END_OF_MAP) {
if (PageHighMem(pfn_to_page(pfn)))
cnt++;
pfn = memory_bm_next_pfn(bm);
}
return cnt;
}
static unsigned int safe_highmem_pages;
static struct memory_bitmap *safe_highmem_bm;
/**
* prepare_highmem_image - Allocate memory for loading highmem data from image.
* @bm: Pointer to an uninitialized memory bitmap structure.
* @nr_highmem_p: Pointer to the number of highmem image pages.
*
* Try to allocate as many highmem pages as there are highmem image pages
* (@nr_highmem_p points to the variable containing the number of highmem image
* pages). The pages that are "safe" (ie. will not be overwritten when the
* hibernation image is restored entirely) have the corresponding bits set in
* @bm (it must be uninitialized).
*
* NOTE: This function should not be called if there are no highmem image pages.
*/
static int prepare_highmem_image(struct memory_bitmap *bm,
unsigned int *nr_highmem_p)
{
unsigned int to_alloc;
if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
return -ENOMEM;
if (get_highmem_buffer(PG_SAFE))
return -ENOMEM;
to_alloc = count_free_highmem_pages();
if (to_alloc > *nr_highmem_p)
to_alloc = *nr_highmem_p;
else
*nr_highmem_p = to_alloc;
safe_highmem_pages = 0;
while (to_alloc-- > 0) {
struct page *page;
page = alloc_page(__GFP_HIGHMEM);
if (!swsusp_page_is_free(page)) {
/* The page is "safe", set its bit the bitmap */
memory_bm_set_bit(bm, page_to_pfn(page));
safe_highmem_pages++;
}
/* Mark the page as allocated */
swsusp_set_page_forbidden(page);
swsusp_set_page_free(page);
}
memory_bm_position_reset(bm);
safe_highmem_bm = bm;
return 0;
}
static struct page *last_highmem_page;
/**
* get_highmem_page_buffer - Prepare a buffer to store a highmem image page.
*
* For a given highmem image page get a buffer that suspend_write_next() should
* return to its caller to write to.
*
* If the page is to be saved to its "original" page frame or a copy of
* the page is to be made in the highmem, @buffer is returned. Otherwise,
* the copy of the page is to be made in normal memory, so the address of
* the copy is returned.
*
* If @buffer is returned, the caller of suspend_write_next() will write
* the page's contents to @buffer, so they will have to be copied to the
* right location on the next call to suspend_write_next() and it is done
* with the help of copy_last_highmem_page(). For this purpose, if
* @buffer is returned, @last_highmem_page is set to the page to which
* the data will have to be copied from @buffer.
*/
static void *get_highmem_page_buffer(struct page *page,
struct chain_allocator *ca)
{
struct highmem_pbe *pbe;
void *kaddr;
if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
/*
* We have allocated the "original" page frame and we can
* use it directly to store the loaded page.
*/
last_highmem_page = page;
return buffer;
}
/*
* The "original" page frame has not been allocated and we have to
* use a "safe" page frame to store the loaded page.
*/
pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
if (!pbe) {
swsusp_free();
return ERR_PTR(-ENOMEM);
}
pbe->orig_page = page;
if (safe_highmem_pages > 0) {
struct page *tmp;
/* Copy of the page will be stored in high memory */
kaddr = buffer;
tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
safe_highmem_pages--;
last_highmem_page = tmp;
pbe->copy_page = tmp;
} else {
/* Copy of the page will be stored in normal memory */
kaddr = __get_safe_page(ca->gfp_mask);
if (!kaddr)
return ERR_PTR(-ENOMEM);
pbe->copy_page = virt_to_page(kaddr);
}
pbe->next = highmem_pblist;
highmem_pblist = pbe;
return kaddr;
}
/**
* copy_last_highmem_page - Copy most the most recent highmem image page.
*
* Copy the contents of a highmem image from @buffer, where the caller of
* snapshot_write_next() has stored them, to the right location represented by
* @last_highmem_page .
*/
static void copy_last_highmem_page(void)
{
if (last_highmem_page) {
void *dst;
dst = kmap_atomic(last_highmem_page);
copy_page(dst, buffer);
kunmap_atomic(dst);
last_highmem_page = NULL;
}
}
static inline int last_highmem_page_copied(void)
{
return !last_highmem_page;
}
static inline void free_highmem_data(void)
{
if (safe_highmem_bm)
memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
if (buffer)
free_image_page(buffer, PG_UNSAFE_CLEAR);
}
#else
static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { 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 */
#define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
/**
* prepare_image - Make room for loading hibernation image.
* @new_bm: Uninitialized memory bitmap structure.
* @bm: Memory bitmap with unsafe pages marked.
* @zero_bm: Memory bitmap containing the zero pages.
*
* Use @bm to mark the pages that will be overwritten in the process of
* restoring the system memory state from the suspend image ("unsafe" pages)
* and allocate memory for the image.
*
* The idea is to allocate a new memory bitmap first and then allocate
* as many pages as needed for image data, but without specifying what those
* pages will be used for just yet. Instead, we mark them all as allocated and
* create a lists of "safe" pages to be used later. On systems with high
* memory a list of "safe" highmem pages is created too.
*
* Because it was not known which pages were unsafe when @zero_bm was created,
* make a copy of it and recreate it within safe pages.
*/
static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm,
struct memory_bitmap *zero_bm)
{
unsigned int nr_pages, nr_highmem;
struct memory_bitmap tmp;
struct linked_page *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);
mark_unsafe_pages(bm);
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);
/* Make a copy of zero_bm so it can be created in safe pages */
error = memory_bm_create(&tmp, GFP_ATOMIC, PG_SAFE);
if (error)
goto Free;
duplicate_memory_bitmap(&tmp, zero_bm);
memory_bm_free(zero_bm, PG_UNSAFE_KEEP);
/* Recreate zero_bm in safe pages */
error = memory_bm_create(zero_bm, GFP_ATOMIC, PG_SAFE);
if (error)
goto Free;
duplicate_memory_bitmap(zero_bm, &tmp);
memory_bm_free(&tmp, PG_UNSAFE_CLEAR);
/* At this point zero_bm is in safe pages and it can be used for restoring. */
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.
*
* nr_copy_pages cannot be less than allocated_unsafe_pages too.
*/
nr_pages = (nr_zero_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 = safe_pages_list;
safe_pages_list = lp;
nr_pages--;
}
/* Preallocate memory for the image */
nr_pages = (nr_zero_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--;
}
return 0;
Free:
swsusp_free();
return error;
}
/**
* get_buffer - Get the address to store the next image data page.
*
* Get the address that snapshot_write_next() should return to its caller to
* write to.
*/
static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
{
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 = __get_safe_page(ca->gfp_mask);
if (!pbe->address)
return ERR_PTR(-ENOMEM);
pbe->next = restore_pblist;
restore_pblist = pbe;
return pbe->address;
}
/**
* snapshot_write_next - Get the address to store the next image page.
* @handle: Snapshot handle structure to guide the writing.
*
* On the first call, @handle should point to a zeroed snapshot_handle
* structure. The structure gets populated then and a pointer to it should be
* passed to this function every next time.
*
* On success, the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory
* location computed by the data_of() macro.
*
* The function returns 0 to indicate the "end of file" condition. Negative
* numbers are returned on errors, in which cases the structure pointed to by
* @handle is not updated and should not be used any more.
*/
int snapshot_write_next(struct snapshot_handle *handle)
{
static struct chain_allocator ca;
int error;
next:
/* Check if we have already loaded the entire image */
if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages + nr_zero_pages)
return 0;
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;
safe_pages_list = NULL;
error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
if (error)
return error;
error = memory_bm_create(&zero_bm, GFP_ATOMIC, PG_ANY);
if (error)
return error;
nr_zero_pages = 0;
hibernate_restore_protection_begin();
} else if (handle->cur <= nr_meta_pages + 1) {
error = unpack_orig_pfns(buffer, ©_bm, &zero_bm);
if (error)
return error;
if (handle->cur == nr_meta_pages + 1) {
error = prepare_image(&orig_bm, ©_bm, &zero_bm);
if (error)
return error;
chain_init(&ca, GFP_ATOMIC, PG_SAFE);
memory_bm_position_reset(&orig_bm);
memory_bm_position_reset(&zero_bm);
restore_pblist = NULL;
handle->buffer = get_buffer(&orig_bm, &ca);
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
}
} else {
copy_last_highmem_page();
error = hibernate_restore_protect_page(handle->buffer);
if (error)
return error;
handle->buffer = get_buffer(&orig_bm, &ca);
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
}
handle->sync_read = (handle->buffer == buffer);
handle->cur++;
/* Zero pages were not included in the image, memset it and move on. */
if (handle->cur > nr_meta_pages + 1 &&
memory_bm_test_bit(&zero_bm, memory_bm_get_current(&orig_bm))) {
memset(handle->buffer, 0, PAGE_SIZE);
goto next;
}
return PAGE_SIZE;
}
/**
* snapshot_write_finalize - Complete the loading of a hibernation image.
*
* Must be called after the last call to snapshot_write_next() in case the last
* page in the image happens to be a highmem page and its contents should be
* stored in highmem. Additionally, it recycles bitmap memory that's not
* necessary any more.
*/
int snapshot_write_finalize(struct snapshot_handle *handle)
{
int error;
copy_last_highmem_page();
error = hibernate_restore_protect_page(handle->buffer);
/* Do that only if we have loaded the image entirely */
if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages + nr_zero_pages) {
memory_bm_recycle(&orig_bm);
free_highmem_data();
}
return error;
}
int snapshot_image_loaded(struct snapshot_handle *handle)
{
return !(!nr_copy_pages || !last_highmem_page_copied() ||
handle->cur <= nr_meta_pages + nr_copy_pages + nr_zero_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 - Put highmem image pages into their original locations.
*
* For each highmem page that was in use before hibernation and is included in
* the image, and also has been allocated by the "restore" kernel, swap its
* current contents with the previous (ie. "before hibernation") ones.
*
* If the restore eventually fails, we can call this function once again and
* restore the highmem state as seen by the restore kernel.
*/
int restore_highmem(void)
{
struct highmem_pbe *pbe = highmem_pblist;
void *buf;
if (!pbe)
return 0;
buf = get_image_page(GFP_ATOMIC, PG_SAFE);
if (!buf)
return -ENOMEM;
while (pbe) {
swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
pbe = pbe->next;
}
free_image_page(buf, PG_UNSAFE_CLEAR);
return 0;
}
#endif /* CONFIG_HIGHMEM */
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