/*
* linux/kernel/power/swsusp.c
*
* This file provides code to write suspend image to swap and read it back.
*
* Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
* Copyright (C) 1998,2001-2005 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
*
* Rafael J. Wysocki <rjw@sisk.pl>
* Reworked the freeing of memory and the handling of swap
*
* More state savers are welcome. Especially for the scsi layer...
*
* For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
*/
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/swap.h>
#include <linux/pm.h>
#include <linux/swapops.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include "power.h"
/*
* Preferred image size in bytes (tunable via /sys/power/image_size).
* When it is set to N, swsusp will do its best to ensure the image
* size will not exceed N bytes, but if that is impossible, it will
* try to create the smallest image possible.
*/
unsigned long image_size = 500 * 1024 * 1024;
int in_suspend __nosavedata = 0;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void);
int restore_highmem(void);
#else
static inline int restore_highmem(void) { return 0; }
static inline unsigned int count_highmem_pages(void) { return 0; }
#endif
/**
* The following functions are used for tracing the allocated
* swap pages, so that they can be freed in case of an error.
*
* The functions operate on a linked bitmap structure defined
* in power.h
*/
void free_bitmap(struct bitmap_page *bitmap)
{
struct bitmap_page *bp;
while (bitmap) {
bp = bitmap->next;
free_page((unsigned long)bitmap);
bitmap = bp;
}
}
struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
{
struct bitmap_page *bitmap, *bp;
unsigned int n;
if (!nr_bits)
return NULL;
bitmap = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bitmap;
for (n = BITMAP_PAGE_BITS; n < nr_bits; n += BITMAP_PAGE_BITS) {
bp->next = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bp->next;
if (!bp) {
free_bitmap(bitmap);
return NULL;
}
}
return bitmap;
}
static int bitmap_set(struct bitmap_page *bitmap, unsigned long bit)
{
unsigned int n;
n = BITMAP_PAGE_BITS;
while (bitmap && n <= bit) {
n += BITMAP_PAGE_BITS;
bitmap = bitmap->next;
}
if (!bitmap)
return -EINVAL;
n -= BITMAP_PAGE_BITS;
bit -= n;
n = 0;
while (bit >= BITS_PER_CHUNK) {
bit -= BITS_PER_CHUNK;
n++;
}
bitmap->chunks[n] |= (1UL << bit);
return 0;
}
sector_t alloc_swapdev_block(int swap, struct bitmap_page *bitmap)
{
unsigned long offset;
offset = swp_offset(get_swap_page_of_type(swap));
if (offset) {
if (bitmap_set(bitmap, offset))
swap_free(swp_entry(swap, offset));
else
return swapdev_block(swap, offset);
}
return 0;
}
void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
{
unsigned int bit, n;
unsigned long test;
bit = 0;
while (bitmap) {
for (n = 0; n < BITMAP_PAGE_CHUNKS; n++)
for (test = 1UL; test; test <<= 1) {
if (bitmap->chunks[n] & test)
swap_free(swp_entry(swap, bit));
bit++;
}
bitmap = bitmap->next;
}
}
/**
* swsusp_show_speed - print the time elapsed between two events represented by
* @start and @stop
*
* @nr_pages - number of pages processed between @start and @stop
* @msg - introductory message to print
*/
void swsusp_show_speed(struct timeval *start, struct timeval *stop,
unsigned nr_pages, char *msg)
{
s64 elapsed_centisecs64;
int centisecs;
int k;
int kps;
elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
centisecs = elapsed_centisecs64;
if (centisecs == 0)
centisecs = 1; /* avoid div-by-zero */
k = nr_pages * (PAGE_SIZE / 1024);
kps = (k * 100) / centisecs;
printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
centisecs / 100, centisecs % 100,
kps / 1000, (kps % 1000) / 10);
}
/**
* swsusp_shrink_memory - Try to free as much memory as needed
*
* ... but do not OOM-kill anyone
*
* Notice: all userland should be stopped before it is called, or
* livelock is possible.
*/
#define SHRINK_BITE 10000
static inline unsigned long __shrink_memory(long tmp)
{
if (tmp > SHRINK_BITE)
tmp = SHRINK_BITE;
return shrink_all_memory(tmp);
}
int swsusp_shrink_memory(void)
{
long tmp;
struct zone *zone;
unsigned long pages = 0;
unsigned int i = 0;
char *p = "-\\|/";
struct timeval start, stop;
printk("Shrinking memory... ");
do_gettimeofday(&start);
do {
long size, highmem_size;
highmem_size = count_highmem_pages();
size = count_data_pages() + PAGES_FOR_IO;
tmp = size;
size += highmem_size;
for_each_zone (zone)
if (populated_zone(zone)) {
if (is_highmem(zone)) {
highmem_size -= zone->free_pages;
} else {
tmp -= zone->free_pages;
tmp += zone->lowmem_reserve[ZONE_NORMAL];
tmp += snapshot_additional_pages(zone);
}
}
if (highmem_size < 0)
highmem_size = 0;
tmp += highmem_size;
if (tmp > 0) {
tmp = __shrink_memory(tmp);
if (!tmp)
return -ENOMEM;
pages += tmp;
} else if (size > image_size / PAGE_SIZE) {
tmp = __shrink_memory(size - (image_size / PAGE_SIZE));
pages += tmp;
}
printk("\b%c", p[i++%4]);
} while (tmp > 0);
do_gettimeofday(&stop);
printk("\bdone (%lu pages freed)\n", pages);
swsusp_show_speed(&start, &stop, pages, "Freed");
return 0;
}
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");
goto Enable_irqs;
}
save_processor_state();
if ((error = swsusp_arch_suspend()))
printk(KERN_ERR "Error %d suspending\n", error);
/* Restore control flow magically appears here */
restore_processor_state();
/* NOTE: device_power_up() is just a resume() for devices
* that suspended with irqs off ... no overall powerup.
*/
device_power_up();
Enable_irqs:
local_irq_enable();
return error;
}
int swsusp_resume(void)
{
int error;
local_irq_disable();
/* NOTE: device_power_down() is just a suspend() with irqs off;
* it has no special "power things down" semantics
*/
if (device_power_down(PMSG_PRETHAW))
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 = restore_highmem();
if (!error) {
error = swsusp_arch_resume();
/* The code below is only ever reached in case of a failure.
* Otherwise execution continues at place where
* swsusp_arch_suspend() was called
*/
BUG_ON(!error);
/* This call to restore_highmem() undos the previous one */
restore_highmem();
}
/* The only reason why swsusp_arch_resume() can fail is memory being
* very tight, so we have to free it as soon as we can to avoid
* subsequent failures
*/
swsusp_free();
restore_processor_state();
touch_softlockup_watchdog();
device_power_up();
local_irq_enable();
return error;
}
