linux/kernel/power/swsusp.c
Pavel Pisa 4dc3b16ba1 [PATCH] DocBook: changes and extensions to the kernel documentation
I have recompiled Linux kernel 2.6.11.5 documentation for me and our
university students again.  The documentation could be extended for more
sources which are equipped by structured comments for recent 2.6 kernels.  I
have tried to proceed with that task.  I have done that more times from 2.6.0
time and it gets boring to do same changes again and again.  Linux kernel
compiles after changes for i386 and ARM targets.  I have added references to
some more files into kernel-api book, I have added some section names as well.
 So please, check that changes do not break something and that categories are
not too much skewed.

I have changed kernel-doc to accept "fastcall" and "asmlinkage" words reserved
by kernel convention.  Most of the other changes are modifications in the
comments to make kernel-doc happy, accept some parameters description and do
not bail out on errors.  Changed <pid> to @pid in the description, moved some
#ifdef before comments to correct function to comments bindings, etc.

You can see result of the modified documentation build at
  http://cmp.felk.cvut.cz/~pisa/linux/lkdb-2.6.11.tar.gz

Some more sources are ready to be included into kernel-doc generated
documentation.  Sources has been added into kernel-api for now.  Some more
section names added and probably some more chaos introduced as result of quick
cleanup work.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Martin Waitz <tali@admingilde.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 08:59:25 -07:00

1433 lines
32 KiB
C

/*
* 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 <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 */
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;
pr_debug("suspend: (pages needed: %d + %d free: %d)\n",
nr_copy_pages, PAGES_FOR_IO, nr_free_pages());
pagedir_nosave = NULL;
if (!enough_free_mem())
return -ENOMEM;
if (!enough_swap())
return -ENOSPC;
nr_copy_pages = calc_nr(nr_copy_pages);
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)
{
int error = 0;
if ((error = swsusp_swap_check())) {
printk(KERN_ERR "swsusp: FATAL: cannot find swap device, try "
"swapon -a!\n");
return error;
}
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))) {
printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
local_irq_enable();
swsusp_free();
return error;
}
save_processor_state();
if ((error = swsusp_arch_suspend()))
swsusp_free();
/* 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;
}
/* More restore stuff */
/*
* Returns true if given address/order collides with any orig_address
*/
static int does_collide_order(unsigned long addr, int order)
{
int i;
for (i=0; i < (1<<order); i++)
if (!PageNosaveFree(virt_to_page(addr + i * PAGE_SIZE)))
return 1;
return 0;
}
/**
* 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 (does_collide_order(m, 0)) {
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 (does_collide_order((unsigned long)pbpage, 0)) {
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(swsusp_info.cpus != num_online_cpus())
return "number of cpus";
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;
}
extern dev_t name_to_dev_t(const char *line);
/**
* 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;
if (!swsusp_resume_device) {
if (!strlen(resume_file))
return -ENOENT;
swsusp_resume_device = name_to_dev_t(resume_file);
pr_debug("swsusp: Resume From Partition %s\n", resume_file);
} else {
pr_debug("swsusp: Resume From Partition %d:%d\n",
MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
}
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);
}