path: root/kernel/power/swsusp.c

/*
 * 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
 *
 * Andreas Steinmetz <ast@domdv.de>:
 * Added encrypted suspend option
 *
 * 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/bitops.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/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 <linux/random.h>
#include <linux/crypto.h>
#include <asm/scatterlist.h>

#include "power.h"

#define CIPHER "aes"
#define MAXKEY 32
#define MAXIV  32

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 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;

#define SWSUSP_SIG	"S1SUSPEND"

static struct swsusp_header {
	char reserved[PAGE_SIZE - 20 - MAXKEY - MAXIV - sizeof(swp_entry_t)];
	u8 key_iv[MAXKEY+MAXIV];
	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;

/*
 * 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 write_page(unsigned long addr, swp_entry_t *loc);
static int bio_read_page(pgoff_t page_off, void *page);

static u8 key_iv[MAXKEY+MAXIV];

#ifdef CONFIG_SWSUSP_ENCRYPT

static int crypto_init(int mode, void **mem)
{
	int error = 0;
	int len;
	char *modemsg;
	struct crypto_tfm *tfm;

	modemsg = mode ? "suspend not possible" : "resume not possible";

	tfm = crypto_alloc_tfm(CIPHER, CRYPTO_TFM_MODE_CBC);
	if(!tfm) {
		printk(KERN_ERR "swsusp: no tfm, %s\n", modemsg);
		error = -EINVAL;
		goto out;
	}

	if(MAXKEY < crypto_tfm_alg_min_keysize(tfm)) {
		printk(KERN_ERR "swsusp: key buffer too small, %s\n", modemsg);
		error = -ENOKEY;
		goto fail;
	}

	if (mode)
		get_random_bytes(key_iv, MAXKEY+MAXIV);

	len = crypto_tfm_alg_max_keysize(tfm);
	if (len > MAXKEY)
		len = MAXKEY;

	if (crypto_cipher_setkey(tfm, key_iv, len)) {
		printk(KERN_ERR "swsusp: key setup failure, %s\n", modemsg);
		error = -EKEYREJECTED;
		goto fail;
	}

	len = crypto_tfm_alg_ivsize(tfm);

	if (MAXIV < len) {
		printk(KERN_ERR "swsusp: iv buffer too small, %s\n", modemsg);
		error = -EOVERFLOW;
		goto fail;
	}

	crypto_cipher_set_iv(tfm, key_iv+MAXKEY, len);

	*mem=(void *)tfm;

	goto out;

fail:	crypto_free_tfm(tfm);
out:	return error;
}

static __inline__ void crypto_exit(void *mem)
{
	crypto_free_tfm((struct crypto_tfm *)mem);
}

static __inline__ int crypto_write(struct pbe *p, void *mem)
{
	int error = 0;
	struct scatterlist src, dst;

	src.page   = virt_to_page(p->address);
	src.offset = 0;
	src.length = PAGE_SIZE;