linux/kernel/power/snapshot.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) 1998-2005 Pavel Machek <pavel@suse.cz>
*
* This file is released under the GPLv2, and is based on swsusp.c.
*
*/
#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 <linux/random.h>
#include <linux/crypto.h>
#include <asm/scatterlist.h>
#include "power.h"
#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;
}
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, *p;
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);
/* This is necessary for swsusp_free() */
for_each_pb_page (p, pagedir_nosave)
SetPageNosaveFree(virt_to_page(p));
for_each_pbe(p, pagedir_nosave)
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()
*/
void free_pagedir(struct pbe *pblist)
{
struct pbe *pbe;
while (pblist) {
pbe = (pblist + PB_PAGE_SKIP)->next;
ClearPageNosave(virt_to_page(pblist));
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()
*/
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);
}
static void *alloc_image_page(void)
{
void *res = (void *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
if (res) {
SetPageNosave(virt_to_page(res));
SetPageNosaveFree(virt_to_page(res));
}
return res;
}
/**
* 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 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 *)alloc_image_page();
/* 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 = (struct pbe *)alloc_image_page();
}
if (!pbe) { /* get_zeroed_page() failed */
free_pagedir(pblist);
pblist = NULL;
}
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));
}
}
}
}
/**
* 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)
{
pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
return nr_free_pages() > (nr_copy_pages + PAGES_FOR_IO +
nr_copy_pages/PBES_PER_PAGE + !!(nr_copy_pages%PBES_PER_PAGE));
}
static int swsusp_alloc(void)
{
struct pbe * p;
pagedir_nosave = NULL;
if (MAX_PBES < nr_copy_pages / PBES_PER_PAGE +
!!(nr_copy_pages % PBES_PER_PAGE))
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;
for_each_pbe (p, pagedir_save) {
p->address = (unsigned long)alloc_image_page();
if (!p->address) {
printk(KERN_ERR "suspend: Allocating image pages failed.\n");
swsusp_free();
return -ENOMEM;
}
}
return 0;
}
static int suspend_prepare_image(void)
{
int error;
pr_debug("swsusp: critical section: \n");
if (save_highmem()) {
printk(KERN_CRIT "swsusp: 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);
pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
nr_copy_pages,
nr_copy_pages/PBES_PER_PAGE + !!(nr_copy_pages%PBES_PER_PAGE),
PAGES_FOR_IO, nr_free_pages());
if (!enough_free_mem()) {
printk(KERN_ERR "swsusp: Not enough free memory\n");
return -ENOMEM;
}
if (!enough_swap()) {
printk(KERN_ERR "swsusp: Not enough free swap\n");
return -ENOSPC;
}
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;
}
asmlinkage int swsusp_save(void)
{
return suspend_prepare_image();
}