/* * 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 "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_HIGHMEMunsigned int count_highmem_pages(void);int save_highmem(void);int restore_highmem(void);#elsestatic int save_highmem(void) { return 0; }static int restore_highmem(void) { return 0; }static 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;} unsigned long alloc_swap_page(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));			offset = 0;		}	}	return offset;} 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_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 int swsusp_shrink_memory(void){	long size, tmp;	struct zone *zone;	unsigned long pages = 0;	unsigned int i = 0;	char *p = "-\\|/"; 	printk("Shrinking memory...  ");	do {		size = 2 * count_highmem_pages();		size += size / 50 + count_data_pages();		size += (size + PBES_PER_PAGE - 1) / PBES_PER_PAGE +			PAGES_FOR_IO;		tmp = size;		for_each_zone (zone)			if (!is_highmem(zone))				tmp -= zone->free_pages;		if (tmp > 0) {			tmp = shrink_all_memory(SHRINK_BITE);			if (!tmp)				return -ENOMEM;			pages += tmp;		} else if (size > image_size / PAGE_SIZE) {			tmp = shrink_all_memory(SHRINK_BITE);			pages += tmp;		}		printk("\b%c", p[i++%4]);	} while (tmp > 0);	printk("\bdone (%lu pages freed)\n", pages); 	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;	} 	if ((error = save_highmem())) {		printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");		goto Restore_highmem;	} 	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();Restore_highmem:	restore_highmem();	device_power_up();Enable_irqs:	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);	/* 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();	restore_highmem();	touch_softlockup_watchdog();	device_power_up();	local_irq_enable();	return error;}