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linux/kernel/power/swsusp.c

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/*
* linux/kernel/power/swsusp.c
*
* This file is to realize architecture-independent
* machine suspend feature using pretty near only high-level routines
*
* Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
* Copyright (C) 1998,2001-2004 Pavel Machek <pavel@suse.cz>
*
* This file is released under the GPLv2.
*
* I'd like to thank the following people for their work:
*
* Pavel Machek <pavel@ucw.cz>:
* Modifications, defectiveness pointing, being with me at the very beginning,
* suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
*
* Steve Doddi <dirk@loth.demon.co.uk>:
* Support the possibility of hardware state restoring.
*
* Raph <grey.havens@earthling.net>:
* Support for preserving states of network devices and virtual console
* (including X and svgatextmode)
*
* Kurt Garloff <garloff@suse.de>:
* Straightened the critical function in order to prevent compilers from
* playing tricks with local variables.
*
* Andreas Mohr <a.mohr@mailto.de>
*
* Alex Badea <vampire@go.ro>:
* Fixed runaway init
*
* More state savers are welcome. Especially for the scsi layer...
*
* For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/smp_lock.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/version.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/bitops.h>
#include <linux/vt_kern.h>
#include <linux/kbd_kern.h>
#include <linux/keyboard.h>
#include <linux/spinlock.h>
#include <linux/genhd.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/swap.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/buffer_head.h>
#include <linux/swapops.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>
#include <linux/bio.h>
#include <linux/mount.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"
/* References to section boundaries */
extern const void __nosave_begin, __nosave_end;
/* Variables to be preserved over suspend */
static int nr_copy_pages_check;
extern char resume_file[];
/* Local variables that should not be affected by save */
static unsigned int nr_copy_pages __nosavedata = 0;
/* Suspend pagedir is allocated before final copy, therefore it
must be freed after resume
Warning: this is evil. There are actually two pagedirs at time of
resume. One is "pagedir_save", which is empty frame allocated at
time of suspend, that must be freed. Second is "pagedir_nosave",
allocated at time of resume, that travels through memory not to
collide with anything.
Warning: this is even more evil than it seems. Pagedirs this file
talks about are completely different from page directories used by
MMU hardware.
*/
suspend_pagedir_t *pagedir_nosave __nosavedata = NULL;
static suspend_pagedir_t *pagedir_save;
#define SWSUSP_SIG "S1SUSPEND"
static struct swsusp_header {
char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
swp_entry_t swsusp_info;
char orig_sig[10];
char sig[10];
} __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
static struct swsusp_info swsusp_info;
/*
* XXX: We try to keep some more pages free so that I/O operations succeed
* without paging. Might this be more?
*/
#define PAGES_FOR_IO 512
/*
* Saving part...
*/
/* We memorize in swapfile_used what swap devices are used for suspension */
#define SWAPFILE_UNUSED 0
#define SWAPFILE_SUSPEND 1 /* This is the suspending device */
#define SWAPFILE_IGNORED 2 /* Those are other swap devices ignored for suspension */
static unsigned short swapfile_used[MAX_SWAPFILES];
static unsigned short root_swap;
static int mark_swapfiles(swp_entry_t prev)
{
int error;
rw_swap_page_sync(READ,
swp_entry(root_swap, 0),
virt_to_page((unsigned long)&swsusp_header));
if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
!memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
swsusp_header.swsusp_info = prev;
error = rw_swap_page_sync(WRITE,
swp_entry(root_swap, 0),
virt_to_page((unsigned long)
&swsusp_header));
} else {
pr_debug("swsusp: Partition is not swap space.\n");
error = -ENODEV;
}
return error;
}
/*
* Check whether the swap device is the specified resume
* device, irrespective of whether they are specified by
* identical names.
*
* (Thus, device inode aliasing is allowed. You can say /dev/hda4
* instead of /dev/ide/host0/bus0/target0/lun0/part4 [if using devfs]
* and they'll be considered the same device. This is *necessary* for
* devfs, since the resume code can only recognize the form /dev/hda4,
* but the suspend code would see the long name.)
*/
static int is_resume_device(const struct swap_info_struct *swap_info)
{
struct file *file = swap_info->swap_file;
struct inode *inode = file->f_dentry->d_inode;
return S_ISBLK(inode->i_mode) &&
swsusp_resume_device == MKDEV(imajor(inode), iminor(inode));
}
static int swsusp_swap_check(void) /* This is called before saving image */
{
int i, len;
len=strlen(resume_file);
root_swap = 0xFFFF;
swap_list_lock();
for (i=0; i<MAX_SWAPFILES; i++) {
if (swap_info[i].flags == 0) {
swapfile_used[i]=SWAPFILE_UNUSED;
} else {
if (!len) {
printk(KERN_WARNING "resume= option should be used to set suspend device" );
if (root_swap == 0xFFFF) {
swapfile_used[i] = SWAPFILE_SUSPEND;
root_swap = i;
} else
swapfile_used[i] = SWAPFILE_IGNORED;
} else {
/* we ignore all swap devices that are not the resume_file */
if (is_resume_device(&swap_info[i])) {
swapfile_used[i] = SWAPFILE_SUSPEND;
root_swap = i;
} else {
swapfile_used[i] = SWAPFILE_IGNORED;
}
}
}
}
swap_list_unlock();
return (root_swap != 0xffff) ? 0 : -ENODEV;
}
/**
* This is called after saving image so modification
* will be lost after resume... and that's what we want.
* we make the device unusable. A new call to
* lock_swapdevices can unlock the devices.
*/
static void lock_swapdevices(void)
{
int i;
swap_list_lock();
for (i = 0; i< MAX_SWAPFILES; i++)
if (swapfile_used[i] == SWAPFILE_IGNORED) {
swap_info[i].flags ^= 0xFF;
}
swap_list_unlock();
}
/**
* write_swap_page - Write one page to a fresh swap location.
* @addr: Address we're writing.
* @loc: Place to store the entry we used.
*
* Allocate a new swap entry and 'sync' it. Note we discard -EIO
* errors. That is an artifact left over from swsusp. It did not
* check the return of rw_swap_page_sync() at all, since most pages
* written back to swap would return -EIO.
* This is a partial improvement, since we will at least return other
* errors, though we need to eventually fix the damn code.
*/
static int write_page(unsigned long addr, swp_entry_t * loc)
{
swp_entry_t entry;
int error = 0;
entry = get_swap_page();
if (swp_offset(entry) &&
swapfile_used[swp_type(entry)] == SWAPFILE_SUSPEND) {
error = rw_swap_page_sync(WRITE, entry,
virt_to_page(addr));
if (error == -EIO)
error = 0;
if (!error)
*loc = entry;
} else
error = -ENOSPC;
return error;
}
/**
* data_free - Free the swap entries used by the saved image.
*
* Walk the list of used swap entries and free each one.
* This is only used for cleanup when suspend fails.
*/
static void data_free(void)
{
swp_entry_t entry;
int i;
for (i = 0; i < nr_copy_pages; i++) {
entry = (pagedir_nosave + i)->swap_address;
if (entry.val)
swap_free(entry);
else
break;
(pagedir_nosave + i)->swap_address = (swp_entry_t){0};
}
}
/**
* data_write - Write saved image to swap.
*
* Walk the list of pages in the image and sync each one to swap.
*/
static int data_write(void)
{
int error = 0, i = 0;
unsigned int mod = nr_copy_pages / 100;
struct pbe *p;
if (!mod)
mod = 1;
printk( "Writing data to swap (%d pages)... ", nr_copy_pages );
for_each_pbe (p, pagedir_nosave) {
if (!(i%mod))
printk( "\b\b\b\b%3d%%", i / mod );
if ((error = write_page(p->address, &(p->swap_address))))
return error;
i++;
}
printk("\b\b\b\bdone\n");
return error;
}
static void dump_info(void)
{
pr_debug(" swsusp: Version: %u\n",swsusp_info.version_code);
pr_debug(" swsusp: Num Pages: %ld\n",swsusp_info.num_physpages);
pr_debug(" swsusp: UTS Sys: %s\n",swsusp_info.uts.sysname);
pr_debug(" swsusp: UTS Node: %s\n",swsusp_info.uts.nodename);
pr_debug(" swsusp: UTS Release: %s\n",swsusp_info.uts.release);
pr_debug(" swsusp: UTS Version: %s\n",swsusp_info.uts.version);
pr_debug(" swsusp: UTS Machine: %s\n",swsusp_info.uts.machine);
pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
pr_debug(" swsusp: Pagedir: %ld Pages\n",swsusp_info.pagedir_pages);
}
static void init_header(void)
{
memset(&swsusp_info, 0, sizeof(swsusp_info));
swsusp_info.version_code = LINUX_VERSION_CODE;
swsusp_info.num_physpages = num_physpages;
memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
swsusp_info.suspend_pagedir = pagedir_nosave;
swsusp_info.cpus = num_online_cpus();
swsusp_info.image_pages = nr_copy_pages;
}
static int close_swap(void)
{
swp_entry_t entry;
int error;
dump_info();
error = write_page((unsigned long)&swsusp_info, &entry);
if (!error) {
printk( "S" );
error = mark_swapfiles(entry);
printk( "|\n" );
}
return error;
}
/**
* free_pagedir_entries - Free pages used by the page directory.
*
* This is used during suspend for error recovery.
*/
static void free_pagedir_entries(void)
{
int i;
for (i = 0; i < swsusp_info.pagedir_pages; i++)
swap_free(swsusp_info.pagedir[i]);
}
/**
* write_pagedir - Write the array of pages holding the page directory.
* @last: Last swap entry we write (needed for header).
*/
static int write_pagedir(void)
{
int error = 0;
unsigned n = 0;
struct pbe * pbe;
printk( "Writing pagedir...");
for_each_pb_page (pbe, pagedir_nosave) {
if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
return error;
}
swsusp_info.pagedir_pages = n;
printk("done (%u pages)\n", n);
return error;
}
/**
* write_suspend_image - Write entire image and metadata.
*
*/
static int write_suspend_image(void)
{
int error;
init_header();
if ((error = data_write()))
goto FreeData;
if ((error = write_pagedir()))
goto FreePagedir;
if ((error = close_swap()))
goto FreePagedir;
Done:
return error;
FreePagedir:
free_pagedir_entries();
FreeData:
data_free();
goto Done;
}
#ifdef CONFIG_HIGHMEM
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%1000))
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)) {
printk("highmem reserved page?!\n");
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;
}
#endif /* CONFIG_HIGHMEM */
static int save_highmem(void)
{
#ifdef CONFIG_HIGHMEM
struct zone *zone;
int res = 0;
pr_debug("swsusp: Saving Highmem\n");
for_each_zone (zone) {
if (is_highmem(zone))
res = save_highmem_zone(zone);
if (res)
return res;
}
#endif
return 0;
}
static int restore_highmem(void)
{
#ifdef CONFIG_HIGHMEM
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);
}
#endif
return 0;
}
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)) {
pr_debug("[nosave pfn 0x%lx]", pfn);
return 0;
}
if (PageNosaveFree(page))
return 0;
return 1;
}
static void count_data_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
nr_copy_pages = 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)
nr_copy_pages += saveable(zone, &zone_pfn);
}
}
static void copy_data_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe * pbe = pagedir_nosave;
pr_debug("copy_data_pages(): pages to copy: %d\n", nr_copy_pages);
for_each_zone (zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
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 = (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);
}
/**
* calc_nr - Determine the number of pages needed for a pbe list.
*/
static int calc_nr(int nr_copy)
{
int extra = 0;
int mod = !!(nr_copy % PBES_PER_PAGE);
int diff = (nr_copy / PBES_PER_PAGE) + mod;
do {
extra += diff;
nr_copy += diff;
mod = !!(nr_copy % PBES_PER_PAGE);
diff = (nr_copy / PBES_PER_PAGE) + mod - extra;
} while (diff > 0);
return nr_copy;
}
/**
* free_pagedir - free pages allocated with alloc_pagedir()
*/
static inline void free_pagedir(struct pbe *pblist)
{
struct pbe *pbe;
while (pblist) {
pbe = (pblist + PB_PAGE_SKIP)->next;
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 void create_pbe_list(struct pbe *pblist, unsigned nr_pages)
{
struct pbe *pbpage, *p;
unsigned 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;
}
pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
}
/**
* 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.
*/
static struct pbe * alloc_pagedir(unsigned nr_pages)
{
unsigned num;
struct pbe *pblist, *pbe;
if (!nr_pages)
return NULL;
pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
pblist = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
pbe = pbe->next, num += PBES_PER_PAGE) {
pbe += PB_PAGE_SKIP;
pbe->next = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
}
if (!pbe) { /* get_zeroed_page() failed */
free_pagedir(pblist);
pblist = NULL;
}
return pblist;
}
/**
* free_image_pages - Free pages allocated for snapshot
*/
static void free_image_pages(void)
{
struct pbe * p;
for_each_pbe (p, pagedir_save) {
if (p->address) {
ClearPageNosave(virt_to_page(p->address));
free_page(p->address);
p->address = 0;
}
}
}
/**
* alloc_image_pages - Allocate pages for the snapshot.
*/
static int alloc_image_pages(void)
{
struct pbe * p;
for_each_pbe (p, pagedir_save) {
p->address = get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
if (!p->address)
return -ENOMEM;
SetPageNosave(virt_to_page(p->address));
}
return 0;
}
void swsusp_free(void)
{
BUG_ON(PageNosave(virt_to_page(pagedir_save)));
BUG_ON(PageNosaveFree(virt_to_page(pagedir_save)));
free_image_pages();
free_pagedir(pagedir_save);
}
/**
* 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(void)
{
if (nr_free_pages() < (nr_copy_pages + PAGES_FOR_IO)) {
pr_debug("swsusp: Not enough free pages: Have %d\n",
nr_free_pages());
return 0;
}
return 1;
}
/**
* enough_swap - Make sure we have enough swap to save the image.
*
* Returns TRUE or FALSE after checking the total amount of swap
* space avaiable.
*
* FIXME: si_swapinfo(&i) returns all swap devices information.
* We should only consider resume_device.
*/
static int enough_swap(void)
{
struct sysinfo i;
si_swapinfo(&i);
if (i.freeswap < (nr_copy_pages + PAGES_FOR_IO)) {
pr_debug("swsusp: Not enough swap. Need %ld\n",i.freeswap);
return 0;
}
return 1;
}
static int swsusp_alloc(void)
{
int error;
pagedir_nosave = NULL;
nr_copy_pages = calc_nr(nr_copy_pages);
pr_debug("suspend: (pages needed: %d + %d free: %d)\n",
nr_copy_pages, PAGES_FOR_IO, nr_free_pages());
if (!enough_free_mem())
return -ENOMEM;
if (!enough_swap())
return -ENOSPC;
if (!(pagedir_save = alloc_pagedir(nr_copy_pages))) {
printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
return -ENOMEM;
}
create_pbe_list(pagedir_save, nr_copy_pages);
pagedir_nosave = pagedir_save;
if ((error = alloc_image_pages())) {
printk(KERN_ERR "suspend: Allocating image pages failed.\n");
swsusp_free();
return error;
}
nr_copy_pages_check = nr_copy_pages;
return 0;
}
static int suspend_prepare_image(void)
{
int error;
pr_debug("swsusp: critical section: \n");
if (save_highmem()) {
printk(KERN_CRIT "Suspend machine: Not enough free pages for highmem\n");
restore_highmem();
return -ENOMEM;
}
drain_local_pages();
count_data_pages();
printk("swsusp: Need to copy %u pages\n", nr_copy_pages);
error = swsusp_alloc();
if (error)
return error;
/* During allocating of suspend pagedir, new cold pages may appear.
* Kill them.
*/
drain_local_pages();
copy_data_pages();
/*
* 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.
*/
printk("swsusp: critical section/: done (%d pages copied)\n", nr_copy_pages );
return 0;
}
/* It is important _NOT_ to umount filesystems at this point. We want
* them synced (in case something goes wrong) but we DO not want to mark
* filesystem clean: it is not. (And it does not matter, if we resume
* correctly, we'll mark system clean, anyway.)
*/
int swsusp_write(void)
{
int error;
device_resume();
lock_swapdevices();
error = write_suspend_image();
/* This will unlock ignored swap devices since writing is finished */
lock_swapdevices();
return error;
}
extern asmlinkage int swsusp_arch_suspend(void);
extern asmlinkage int swsusp_arch_resume(void);
asmlinkage int swsusp_save(void)
{
return suspend_prepare_image();
}
int swsusp_suspend(void)
{
int error;
if ((error = arch_prepare_suspend()))
return error;
local_irq_disable();
/* At this point, device_suspend() has been called, but *not*
* device_power_down(). We *must* device_power_down() now.
* Otherwise, drivers for some devices (e.g. interrupt controllers)
* become desynchronized with the actual state of the hardware
* at resume time, and evil weirdness ensues.
*/
if ((error = device_power_down(PMSG_FREEZE))) {
local_irq_enable();
return error;
}
if ((error = swsusp_swap_check())) {
printk(KERN_ERR "swsusp: FATAL: cannot find swap device, try "
"swapon -a!\n");
local_irq_enable();
return error;
}
save_processor_state();
if ((error = swsusp_arch_suspend()))
printk("Error %d suspending\n", error);
/* Restore control flow magically appears here */
restore_processor_state();
BUG_ON (nr_copy_pages_check != nr_copy_pages);
restore_highmem();
device_power_up();
local_irq_enable();
return error;
}
int swsusp_resume(void)
{
int error;
local_irq_disable();
if (device_power_down(PMSG_FREEZE))
printk(KERN_ERR "Some devices failed to power down, very bad\n");
/* We'll ignore saved state, but this gets preempt count (etc) right */
save_processor_state();
error = swsusp_arch_resume();
/* Code below is only ever reached in case of failure. Otherwise
* execution continues at place where swsusp_arch_suspend was called
*/
BUG_ON(!error);
restore_processor_state();
restore_highmem();
device_power_up();
local_irq_enable();
return error;
}
/**
* 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.
*
* We don't know which pages are usable until we allocate them.
*
* Allocated but unusable (ie eaten) memory pages are linked together
* to create a list, so that we can free them easily
*
* We could have used a type other than (void *)
* for this purpose, but ...
*/
static void **eaten_memory = NULL;
static inline void eat_page(void *page)
{
void **c;
c = eaten_memory;
eaten_memory = page;
*eaten_memory = c;
}
static unsigned long get_usable_page(unsigned gfp_mask)
{
unsigned long m;
m = get_zeroed_page(gfp_mask);
while (!PageNosaveFree(virt_to_page(m))) {
eat_page((void *)m);
m = get_zeroed_page(gfp_mask);
if (!m)
break;
}
return m;
}
static void free_eaten_memory(void)
{
unsigned long m;
void **c;
int i = 0;
c = eaten_memory;
while (c) {
m = (unsigned long)c;
c = *c;
free_page(m);
i++;
}
eaten_memory = NULL;
pr_debug("swsusp: %d unused pages freed\n", i);
}
/**
* check_pagedir - We ensure here that pages that the PBEs point to
* won't collide with pages where we're going to restore from the loaded
* pages later
*/
static int check_pagedir(struct pbe *pblist)
{
struct pbe *p;
/* This is necessary, so that we can free allocated pages
* in case of failure
*/
for_each_pbe (p, pblist)
p->address = 0UL;
for_each_pbe (p, pblist) {
p->address = get_usable_page(GFP_ATOMIC);
if (!p->address)
return -ENOMEM;
}
return 0;
}
/**
* swsusp_pagedir_relocate - It is possible, that some memory pages
* occupied by the list of PBEs collide with pages where we're going to
* restore from the loaded pages later. We relocate them here.
*/
static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *pbpage, *tail, *p;
void *m;
int rel = 0, error = 0;
if (!pblist) /* a sanity check */
return NULL;
pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
swsusp_info.pagedir_pages);
/* Set page flags */
for_each_zone (zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
SetPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}
/* Clear orig addresses */
for_each_pbe (p, pblist)
ClearPageNosaveFree(virt_to_page(p->orig_address));
tail = pblist + PB_PAGE_SKIP;
/* Relocate colliding pages */
for_each_pb_page (pbpage, pblist) {
if (!PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
m = (void *)get_usable_page(GFP_ATOMIC | __GFP_COLD);
if (!m) {
error = -ENOMEM;
break;
}
memcpy(m, (void *)pbpage, PAGE_SIZE);
if (pbpage == pblist)
pblist = (struct pbe *)m;
else
tail->next = (struct pbe *)m;
eat_page((void *)pbpage);
pbpage = (struct pbe *)m;
/* We have to link the PBEs again */
for (p = pbpage; p < pbpage + PB_PAGE_SKIP; p++)
if (p->next) /* needed to save the end */
p->next = p + 1;
rel++;
}
tail = pbpage + PB_PAGE_SKIP;
}
if (error) {
printk("\nswsusp: Out of memory\n\n");
free_pagedir(pblist);
free_eaten_memory();
pblist = NULL;
}
else
printk("swsusp: Relocated %d pages\n", rel);
return pblist;
}
/*
* Using bio to read from swap.
* This code requires a bit more work than just using buffer heads
* but, it is the recommended way for 2.5/2.6.
* The following are to signal the beginning and end of I/O. Bios
* finish asynchronously, while we want them to happen synchronously.
* A simple atomic_t, and a wait loop take care of this problem.
*/
static atomic_t io_done = ATOMIC_INIT(0);
static int end_io(struct bio * bio, unsigned int num, int err)
{
if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
panic("I/O error reading memory image");
atomic_set(&io_done, 0);
return 0;
}
static struct block_device * resume_bdev;
/**
* submit - submit BIO request.
* @rw: READ or WRITE.
* @off physical offset of page.
* @page: page we're reading or writing.
*
* Straight from the textbook - allocate and initialize the bio.
* If we're writing, make sure the page is marked as dirty.
* Then submit it and wait.
*/
static int submit(int rw, pgoff_t page_off, void * page)
{
int error = 0;
struct bio * bio;
bio = bio_alloc(GFP_ATOMIC, 1);
if (!bio)
return -ENOMEM;
bio->bi_sector = page_off * (PAGE_SIZE >> 9);
bio_get(bio);
bio->bi_bdev = resume_bdev;
bio->bi_end_io = end_io;
if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
error = -EFAULT;
goto Done;
}
if (rw == WRITE)
bio_set_pages_dirty(bio);
atomic_set(&io_done, 1);
submit_bio(rw | (1 << BIO_RW_SYNC), bio);
while (atomic_read(&io_done))
yield();
Done:
bio_put(bio);
return error;
}
static int bio_read_page(pgoff_t page_off, void * page)
{
return submit(READ, page_off, page);
}
static int bio_write_page(pgoff_t page_off, void * page)
{
return submit(WRITE, page_off, page);
}
/*
* Sanity check if this image makes sense with this kernel/swap context
* I really don't think that it's foolproof but more than nothing..
*/
static const char * sanity_check(void)
{
dump_info();
if (swsusp_info.version_code != LINUX_VERSION_CODE)
return "kernel version";
if (swsusp_info.num_physpages != num_physpages)
return "memory size";
if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
return "system type";
if (strcmp(swsusp_info.uts.release,system_utsname.release))
return "kernel release";
if (strcmp(swsusp_info.uts.version,system_utsname.version))
return "version";
if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
return "machine";
#if 0
if(swsusp_info.cpus != num_online_cpus())
return "number of cpus";
#endif
return NULL;
}
static int check_header(void)
{
const char * reason = NULL;
int error;
if ((error = bio_read_page(swp_offset(swsusp_header.swsusp_info), &swsusp_info)))
return error;
/* Is this same machine? */
if ((reason = sanity_check())) {
printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
return -EPERM;
}
nr_copy_pages = swsusp_info.image_pages;
return error;
}
static int check_sig(void)
{
int error;
memset(&swsusp_header, 0, sizeof(swsusp_header));
if ((error = bio_read_page(0, &swsusp_header)))
return error;
if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
/*
* Reset swap signature now.
*/
error = bio_write_page(0, &swsusp_header);
} else {
printk(KERN_ERR "swsusp: Suspend partition has wrong signature?\n");
return -EINVAL;
}
if (!error)
pr_debug("swsusp: Signature found, resuming\n");
return error;
}
/**
* data_read - Read image pages from swap.
*
* You do not need to check for overlaps, check_pagedir()
* already did that.
*/
static int data_read(struct pbe *pblist)
{
struct pbe * p;
int error = 0;
int i = 0;
int mod = swsusp_info.image_pages / 100;
if (!mod)
mod = 1;
printk("swsusp: Reading image data (%lu pages): ",
swsusp_info.image_pages);
for_each_pbe (p, pblist) {
if (!(i % mod))
printk("\b\b\b\b%3d%%", i / mod);
error = bio_read_page(swp_offset(p->swap_address),
(void *)p->address);
if (error)
return error;
i++;
}
printk("\b\b\b\bdone\n");
return error;
}
/**
* read_pagedir - Read page backup list pages from swap
*/
static int read_pagedir(struct pbe *pblist)
{
struct pbe *pbpage, *p;
unsigned i = 0;
int error;
if (!pblist)
return -EFAULT;
printk("swsusp: Reading pagedir (%lu pages)\n",
swsusp_info.pagedir_pages);
for_each_pb_page (pbpage, pblist) {
unsigned long offset = swp_offset(swsusp_info.pagedir[i++]);
error = -EFAULT;
if (offset) {
p = (pbpage + PB_PAGE_SKIP)->next;
error = bio_read_page(offset, (void *)pbpage);
(pbpage + PB_PAGE_SKIP)->next = p;
}
if (error)
break;
}
if (error)
free_page((unsigned long)pblist);
BUG_ON(i != swsusp_info.pagedir_pages);
return error;
}
static int check_suspend_image(void)
{
int error = 0;
if ((error = check_sig()))
return error;
if ((error = check_header()))
return error;
return 0;
}
static int read_suspend_image(void)
{
int error = 0;
struct pbe *p;
if (!(p = alloc_pagedir(nr_copy_pages)))
return -ENOMEM;
if ((error = read_pagedir(p)))
return error;
create_pbe_list(p, nr_copy_pages);
if (!(pagedir_nosave = swsusp_pagedir_relocate(p)))
return -ENOMEM;
/* Allocate memory for the image and read the data from swap */
error = check_pagedir(pagedir_nosave);
free_eaten_memory();
if (!error)
error = data_read(pagedir_nosave);
if (error) { /* We fail cleanly */
for_each_pbe (p, pagedir_nosave)
if (p->address) {
free_page(p->address);
p->address = 0UL;
}
free_pagedir(pagedir_nosave);
}
return error;
}
/**
* swsusp_check - Check for saved image in swap
*/
int swsusp_check(void)
{
int error;
resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
if (!IS_ERR(resume_bdev)) {
set_blocksize(resume_bdev, PAGE_SIZE);
error = check_suspend_image();
if (error)
blkdev_put(resume_bdev);
} else
error = PTR_ERR(resume_bdev);
if (!error)
pr_debug("swsusp: resume file found\n");
else
pr_debug("swsusp: Error %d check for resume file\n", error);
return error;
}
/**
* swsusp_read - Read saved image from swap.
*/
int swsusp_read(void)
{
int error;
if (IS_ERR(resume_bdev)) {
pr_debug("swsusp: block device not initialised\n");
return PTR_ERR(resume_bdev);
}
error = read_suspend_image();
blkdev_put(resume_bdev);
if (!error)
pr_debug("swsusp: Reading resume file was successful\n");
else
pr_debug("swsusp: Error %d resuming\n", error);
return error;
}
/**
* swsusp_close - close swap device.
*/
void swsusp_close(void)
{
if (IS_ERR(resume_bdev)) {
pr_debug("swsusp: block device not initialised\n");
return;
}
blkdev_put(resume_bdev);
}
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