linux/kernel/power/snapshot.c

831 lines
20 KiB
C
Raw Normal View History

/*
* linux/kernel/power/snapshot.c
*
* This file provide system snapshot/restore functionality.
*
* Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
*
* This file is released under the GPLv2, and is based on swsusp.c.
*
*/
#include <linux/version.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
#include "power.h"
struct pbe *pagedir_nosave;
static unsigned int nr_copy_pages;
static unsigned int nr_meta_pages;
static unsigned long *buffer;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
unsigned int n = 0;
for_each_zone (zone)
if (is_highmem(zone)) {
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; zone_pfn++) {
struct page *page;
unsigned long pfn = zone_pfn + zone->zone_start_pfn;
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
if (PageReserved(page))
continue;
if (PageNosaveFree(page))
continue;
n++;
}
}
return n;
}
struct highmem_page {
char *data;
struct page *page;
struct highmem_page *next;
};
static struct highmem_page *highmem_copy;
static int save_highmem_zone(struct zone *zone)
{
unsigned long zone_pfn;
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
struct page *page;
struct highmem_page *save;
void *kaddr;
unsigned long pfn = zone_pfn + zone->zone_start_pfn;
if (!(pfn%10000))
printk(".");
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
/*
* This condition results from rvmalloc() sans vmalloc_32()
* and architectural memory reservations. This should be
* corrected eventually when the cases giving rise to this
* are better understood.
*/
if (PageReserved(page))
continue;
BUG_ON(PageNosave(page));
if (PageNosaveFree(page))
continue;
save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
if (!save)
return -ENOMEM;
save->next = highmem_copy;
save->page = page;
save->data = (void *) get_zeroed_page(GFP_ATOMIC);
if (!save->data) {
kfree(save);
return -ENOMEM;
}
kaddr = kmap_atomic(page, KM_USER0);
memcpy(save->data, kaddr, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
highmem_copy = save;
}
return 0;
}
int save_highmem(void)
{
struct zone *zone;
int res = 0;
pr_debug("swsusp: Saving Highmem");
drain_local_pages();
for_each_zone (zone) {
if (is_highmem(zone))
res = save_highmem_zone(zone);
if (res)
return res;
}
printk("\n");
return 0;
}
int restore_highmem(void)
{
printk("swsusp: Restoring Highmem\n");
while (highmem_copy) {
struct highmem_page *save = highmem_copy;
void *kaddr;
highmem_copy = save->next;
kaddr = kmap_atomic(save->page, KM_USER0);
memcpy(kaddr, save->data, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
free_page((long) save->data);
kfree(save);
}
return 0;
}
#endif
static int pfn_is_nosave(unsigned long pfn)
{
unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
}
/**
* saveable - Determine whether a page should be cloned or not.
* @pfn: The page
*
* We save a page if it's Reserved, and not in the range of pages
* statically defined as 'unsaveable', or if it isn't reserved, and
* isn't part of a free chunk of pages.
*/
static int saveable(struct zone *zone, unsigned long *zone_pfn)
{
unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
struct page *page;
if (!pfn_valid(pfn))
return 0;
page = pfn_to_page(pfn);
BUG_ON(PageReserved(page) && PageNosave(page));
if (PageNosave(page))
return 0;
if (PageReserved(page) && pfn_is_nosave(pfn))
return 0;
if (PageNosaveFree(page))
return 0;
return 1;
}
unsigned int count_data_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
unsigned int n = 0;
for_each_zone (zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
n += saveable(zone, &zone_pfn);
}
return n;
}
static void copy_data_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *pbe, *p;
pbe = pblist;
for_each_zone (zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
/* This is necessary for swsusp_free() */
for_each_pb_page (p, pblist)
SetPageNosaveFree(virt_to_page(p));
for_each_pbe (p, pblist)
SetPageNosaveFree(virt_to_page(p->address));
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
if (saveable(zone, &zone_pfn)) {
struct page *page;
page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
BUG_ON(!pbe);
pbe->orig_address = (unsigned long)page_address(page);
/* copy_page is not usable for copying task structs. */
memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
pbe = pbe->next;
}
}
}
BUG_ON(pbe);
}
/**
* free_pagedir - free pages allocated with alloc_pagedir()
*/
static void free_pagedir(struct pbe *pblist, int clear_nosave_free)
{
struct pbe *pbe;
while (pblist) {
pbe = (pblist + PB_PAGE_SKIP)->next;
ClearPageNosave(virt_to_page(pblist));
if (clear_nosave_free)
ClearPageNosaveFree(virt_to_page(pblist));
free_page((unsigned long)pblist);
pblist = pbe;
}
}
/**
* fill_pb_page - Create a list of PBEs on a given memory page
*/
static inline void fill_pb_page(struct pbe *pbpage)
{
struct pbe *p;
p = pbpage;
pbpage += PB_PAGE_SKIP;
do
p->next = p + 1;
while (++p < pbpage);
}
/**
* create_pbe_list - Create a list of PBEs on top of a given chain
* of memory pages allocated with alloc_pagedir()
*/
static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
{
struct pbe *pbpage, *p;
unsigned int num = PBES_PER_PAGE;
for_each_pb_page (pbpage, pblist) {
if (num >= nr_pages)
break;
fill_pb_page(pbpage);
num += PBES_PER_PAGE;
}
if (pbpage) {
for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
p->next = p + 1;
p->next = NULL;
}
}
/**
* On resume it is necessary to trace and eventually free the unsafe
* pages that have been allocated, because they are needed for I/O
* (on x86-64 we likely will "eat" these pages once again while
* creating the temporary page translation tables)
*/
struct eaten_page {
struct eaten_page *next;
char padding[PAGE_SIZE - sizeof(void *)];
};
static struct eaten_page *eaten_pages = NULL;
static void release_eaten_pages(void)
{
struct eaten_page *p, *q;
p = eaten_pages;
while (p) {
q = p->next;
/* We don't want swsusp_free() to free this page again */
ClearPageNosave(virt_to_page(p));
free_page((unsigned long)p);
p = q;
}
eaten_pages = NULL;
}
/**
* @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
* which had been used before suspend.
*
* The unsafe pages are marked with the PG_nosave_free flag
*
* Allocated but unusable (ie eaten) memory pages should be marked
* so that swsusp_free() can release them
*/
static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
{
void *res;
if (safe_needed)
do {
res = (void *)get_zeroed_page(gfp_mask);
if (res && PageNosaveFree(virt_to_page(res))) {
/* This is for swsusp_free() */
SetPageNosave(virt_to_page(res));
((struct eaten_page *)res)->next = eaten_pages;
eaten_pages = res;
}
} while (res && PageNosaveFree(virt_to_page(res)));
else
res = (void *)get_zeroed_page(gfp_mask);
if (res) {
SetPageNosave(virt_to_page(res));
SetPageNosaveFree(virt_to_page(res));
}
return res;
}
unsigned long get_safe_page(gfp_t gfp_mask)
{
return (unsigned long)alloc_image_page(gfp_mask, 1);
}
/**
* alloc_pagedir - Allocate the page directory.
*
* First, determine exactly how many pages we need and
* allocate them.
*
* We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
* struct pbe elements (pbes) and the last element in the page points
* to the next page.
*
* On each page we set up a list of struct_pbe elements.
*/
struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed)
{
unsigned int num;
struct pbe *pblist, *pbe;
if (!nr_pages)
return NULL;
pblist = alloc_image_page(gfp_mask, safe_needed);
/* FIXME: rewrite this ugly loop */
for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
pbe = pbe->next, num += PBES_PER_PAGE) {
pbe += PB_PAGE_SKIP;
pbe->next = alloc_image_page(gfp_mask, safe_needed);
}
if (!pbe) { /* get_zeroed_page() failed */
free_pagedir(pblist, 1);
pblist = NULL;
} else
create_pbe_list(pblist, nr_pages);
return pblist;
}
/**
* Free pages we allocated for suspend. Suspend pages are alocated
* before atomic copy, so we need to free them after resume.
*/
void swsusp_free(void)
{
struct zone *zone;
unsigned long zone_pfn;
for_each_zone(zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
struct page *page;
page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
if (PageNosave(page) && PageNosaveFree(page)) {
ClearPageNosave(page);
ClearPageNosaveFree(page);
free_page((long) page_address(page));
}
}
}
nr_copy_pages = 0;
nr_meta_pages = 0;
pagedir_nosave = NULL;
buffer = NULL;
}
/**
* enough_free_mem - Make sure we enough free memory to snapshot.
*
* Returns TRUE or FALSE after checking the number of available
* free pages.
*/
static int enough_free_mem(unsigned int nr_pages)
{
struct zone *zone;
unsigned int n = 0;
for_each_zone (zone)
if (!is_highmem(zone))
n += zone->free_pages;
pr_debug("swsusp: available memory: %u pages\n", n);
return n > (nr_pages + PAGES_FOR_IO +
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}
static int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
{
struct pbe *p;
for_each_pbe (p, pblist) {
p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
if (!p->address)
return -ENOMEM;
}
return 0;
}
static struct pbe *swsusp_alloc(unsigned int nr_pages)
{
struct pbe *pblist;
if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
return NULL;
}
if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
printk(KERN_ERR "suspend: Allocating image pages failed.\n");
swsusp_free();
return NULL;
}
return pblist;
}
asmlinkage int swsusp_save(void)
{
unsigned int nr_pages;
pr_debug("swsusp: critical section: \n");
drain_local_pages();
nr_pages = count_data_pages();
printk("swsusp: Need to copy %u pages\n", nr_pages);
pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
nr_pages,
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
PAGES_FOR_IO, nr_free_pages());
if (!enough_free_mem(nr_pages)) {
printk(KERN_ERR "swsusp: Not enough free memory\n");
return -ENOMEM;
}
pagedir_nosave = swsusp_alloc(nr_pages);
if (!pagedir_nosave)
return -ENOMEM;
/* During allocating of suspend pagedir, new cold pages may appear.
* Kill them.
*/
drain_local_pages();
copy_data_pages(pagedir_nosave);
/*
* 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_copy_pages = nr_pages;
nr_meta_pages = (nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT;
printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
return 0;
}
static void init_header(struct swsusp_info *info)
{
memset(info, 0, sizeof(struct swsusp_info));
info->version_code = LINUX_VERSION_CODE;
info->num_physpages = num_physpages;
memcpy(&info->uts, &system_utsname, sizeof(system_utsname));
info->cpus = num_online_cpus();
info->image_pages = nr_copy_pages;
info->pages = nr_copy_pages + nr_meta_pages + 1;
info->size = info->pages;
info->size <<= PAGE_SHIFT;
}
/**
* pack_orig_addresses - the .orig_address fields of the PBEs from the
* list starting at @pbe are stored in the array @buf[] (1 page)
*/
static inline struct pbe *pack_orig_addresses(unsigned long *buf, struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
buf[j] = pbe->orig_address;
pbe = pbe->next;
}
if (!pbe)
for (; j < PAGE_SIZE / sizeof(long); j++)
buf[j] = 0;
return pbe;
}
/**
* snapshot_read_next - used for reading the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to read from the snapshot. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the read would
* cross a page boundary otherwise.
*
* The function returns 0 to indicate the end of data stream condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_read_next(struct snapshot_handle *handle, size_t count)
{
if (handle->page > nr_meta_pages + nr_copy_pages)
return 0;
if (!buffer) {
/* This makes the buffer be freed by swsusp_free() */
buffer = alloc_image_page(GFP_ATOMIC, 0);
if (!buffer)
return -ENOMEM;
}
if (!handle->offset) {
init_header((struct swsusp_info *)buffer);
handle->buffer = buffer;
handle->pbe = pagedir_nosave;
}
if (handle->prev < handle->page) {
if (handle->page <= nr_meta_pages) {
handle->pbe = pack_orig_addresses(buffer, handle->pbe);
if (!handle->pbe)
handle->pbe = pagedir_nosave;
} else {
handle->buffer = (void *)handle->pbe->address;
handle->pbe = handle->pbe->next;
}
handle->prev = handle->page;
}
handle->buf_offset = handle->page_offset;
if (handle->page_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->page_offset;
handle->page_offset = 0;
handle->page++;
} else {
handle->page_offset += count;
}
handle->offset += count;
return count;
}
/**
* mark_unsafe_pages - mark the pages that cannot be used for storing
* the image during resume, because they conflict with the pages that
* had been used before suspend
*/
static int mark_unsafe_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *p;
if (!pblist) /* a sanity check */
return -EINVAL;
/* Clear page flags */
for_each_zone (zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn))
ClearPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}
/* Mark orig addresses */
for_each_pbe (p, pblist) {
if (virt_addr_valid(p->orig_address))
SetPageNosaveFree(virt_to_page(p->orig_address));
else
return -EFAULT;
}
return 0;
}
static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
{
/* We assume both lists contain the same number of elements */
while (src) {
dst->orig_address = src->orig_address;
dst = dst->next;
src = src->next;
}
}
static int check_header(struct swsusp_info *info)
{
char *reason = NULL;
if (info->version_code != LINUX_VERSION_CODE)
reason = "kernel version";
if (info->num_physpages != num_physpages)
reason = "memory size";
if (strcmp(info->uts.sysname,system_utsname.sysname))
reason = "system type";
if (strcmp(info->uts.release,system_utsname.release))
reason = "kernel release";
if (strcmp(info->uts.version,system_utsname.version))
reason = "version";
if (strcmp(info->uts.machine,system_utsname.machine))
reason = "machine";
if (reason) {
printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
return -EPERM;
}
return 0;
}
/**
* load header - check the image header and copy data from it
*/
static int load_header(struct snapshot_handle *handle,
struct swsusp_info *info)
{
int error;
struct pbe *pblist;
error = check_header(info);
if (!error) {
pblist = alloc_pagedir(info->image_pages, GFP_ATOMIC, 0);
if (!pblist)
return -ENOMEM;
pagedir_nosave = pblist;
handle->pbe = pblist;
nr_copy_pages = info->image_pages;
nr_meta_pages = info->pages - info->image_pages - 1;
}
return error;
}
/**
* unpack_orig_addresses - copy the elements of @buf[] (1 page) to
* the PBEs in the list starting at @pbe
*/
static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
pbe->orig_address = buf[j];
pbe = pbe->next;
}
return pbe;
}
/**
* create_image - use metadata contained in the PBE list
* pointed to by pagedir_nosave to mark the pages that will
* be overwritten in the process of restoring the system
* memory state from the image and allocate memory for
* the image avoiding these pages
*/
static int create_image(struct snapshot_handle *handle)
{
int error = 0;
struct pbe *p, *pblist;
p = pagedir_nosave;
error = mark_unsafe_pages(p);
if (!error) {
pblist = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
if (pblist)
copy_page_backup_list(pblist, p);
free_pagedir(p, 0);
if (!pblist)
error = -ENOMEM;
}
if (!error)
error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
if (!error) {
release_eaten_pages();
pagedir_nosave = pblist;
} else {
pagedir_nosave = NULL;
handle->pbe = NULL;
nr_copy_pages = 0;
nr_meta_pages = 0;
}
return error;
}
/**
* snapshot_write_next - used for writing the system memory snapshot.
*
* On the first call to it @handle should point to a zeroed
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to write to the image. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the write would
* cross a page boundary otherwise.
*
* The function returns 0 to indicate the "end of file" condition,
* and a negative number is returned on error. In such cases the
* structure pointed to by @handle is not updated and should not be used
* any more.
*/
int snapshot_write_next(struct snapshot_handle *handle, size_t count)
{
int error = 0;
if (handle->prev && handle->page > nr_meta_pages + nr_copy_pages)
return 0;
if (!buffer) {
/* This makes the buffer be freed by swsusp_free() */
buffer = alloc_image_page(GFP_ATOMIC, 0);
if (!buffer)
return -ENOMEM;
}
if (!handle->offset)
handle->buffer = buffer;
if (handle->prev < handle->page) {
if (!handle->prev) {
error = load_header(handle, (struct swsusp_info *)buffer);
if (error)
return error;
} else if (handle->prev <= nr_meta_pages) {
handle->pbe = unpack_orig_addresses(buffer, handle->pbe);
if (!handle->pbe) {
error = create_image(handle);
if (error)
return error;
handle->pbe = pagedir_nosave;
handle->buffer = (void *)handle->pbe->address;
}
} else {
handle->pbe = handle->pbe->next;
handle->buffer = (void *)handle->pbe->address;
}
handle->prev = handle->page;
}
handle->buf_offset = handle->page_offset;
if (handle->page_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->page_offset;
handle->page_offset = 0;
handle->page++;
} else {
handle->page_offset += count;
}
handle->offset += count;
return count;
}
int snapshot_image_loaded(struct snapshot_handle *handle)
{
return !(!handle->pbe || handle->pbe->next || !nr_copy_pages ||
handle->page <= nr_meta_pages + nr_copy_pages);
}