[mirror_ubuntu-artful-kernel.git] / kernel / power / user.c

/*
 * linux/kernel/power/user.c
 *
 * This file provides the user space interface for software suspend/resume.
 *
 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
 *
 * This file is released under the GPLv2.
 *
 */

#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/pm.h>
#include <linux/fs.h>
#include <linux/compat.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>

#include <linux/uaccess.h>

#include "power.h"


#define SNAPSHOT_MINOR	231

static struct snapshot_data {
	struct snapshot_handle handle;
	int swap;
	int mode;
	bool frozen;
	bool ready;
	bool platform_support;
	bool free_bitmaps;
} snapshot_state;

atomic_t snapshot_device_available = ATOMIC_INIT(1);

static int snapshot_open(struct inode *inode, struct file *filp)
{
	struct snapshot_data *data;
	int error, nr_calls = 0;

	if (!hibernation_available())
		return -EPERM;

	if (kernel_is_locked_down())
		return -EPERM;

	lock_system_sleep();

	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
		error = -EBUSY;
		goto Unlock;
	}

	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
		atomic_inc(&snapshot_device_available);
		error = -ENOSYS;
		goto Unlock;
	}
	nonseekable_open(inode, filp);
	data = &snapshot_state;
	filp->private_data = data;
	memset(&data->handle, 0, sizeof(struct snapshot_handle));
	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
		/* Hibernating.  The image device should be accessible. */
		data->swap = swsusp_resume_device ?
			swap_type_of(swsusp_resume_device, 0, NULL) : -1;
		data->mode = O_RDONLY;
		data->free_bitmaps = false;
		error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
		if (error)
			__pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL);
	} else {
		/*
		 * Resuming.  We may need to wait for the image device to
		 * appear.
		 */
		wait_for_device_probe();

		data->swap = -1;
		data->mode = O_WRONLY;
		error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
		if (!error) {
			error = create_basic_memory_bitmaps();
			data->free_bitmaps = !error;
		} else
			nr_calls--;

		if (error)
			__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
	}
	if (error)
		atomic_inc(&snapshot_device_available);

	data->frozen = false;
	data->ready = false;
	data->platform_support = false;

 Unlock:
	unlock_system_sleep();

	return error;
}

static int snapshot_release(struct inode *inode, struct file *filp)
{
	struct snapshot_data *data;

	lock_system_sleep();

	swsusp_free();
	data = filp->private_data;
	free_all_swap_pages(data->swap);
	if (data->frozen) {
		pm_restore_gfp_mask();
		free_basic_memory_bitmaps();
		thaw_processes();
	} else if (data->free_bitmaps) {
		free_basic_memory_bitmaps();
	}
	pm_notifier_call_chain(data->mode == O_RDONLY ?
			PM_POST_HIBERNATION : PM_POST_RESTORE);
	atomic_inc(&snapshot_device_available);

	unlock_system_sleep();

	return 0;
}

static ssize_t snapshot_read(struct file *filp, char __user *buf,
                             size_t count, loff_t *offp)
{
	struct snapshot_data *data;
	ssize_t res;
	loff_t pg_offp = *offp & ~PAGE_MASK;

	lock_system_sleep();

	data = filp->private_data;
	if (!data->ready) {
		res = -ENODATA;
		goto Unlock;
	}
	if (!pg_offp) { /* on page boundary? */
		res = snapshot_read_next(&data->handle);
		if (res <= 0)
			goto Unlock;
	} else {
		res = PAGE_SIZE - pg_offp;
	}

	res = simple_read_from_buffer(buf, count, &pg_offp,
			data_of(data->handle), res);
	if (res > 0)
		*offp += res;

 Unlock:
	unlock_system_sleep();

	return res;
}

static ssize_t snapshot_write(struct file *filp, const char __user *buf,
                              size_t count, loff_t *offp)
{
	struct snapshot_data *data;
	ssize_t res;
	loff_t pg_offp = *offp & ~PAGE_MASK;

	lock_system_sleep();

	data = filp->private_data;

	if (!pg_offp) {
		res = snapshot_write_next(&data->handle);
		if (res <= 0)
			goto unlock;
	} else {
		res = PAGE_SIZE - pg_offp;
	}

	res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
			buf, count);
	if (res > 0)
		*offp += res;
unlock:
	unlock_system_sleep();

	return res;
}

static long snapshot_ioctl(struct file *filp, unsigned int cmd,
							unsigned long arg)
{
	int error = 0;
	struct snapshot_data *data;
	loff_t size;
	sector_t offset;

	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
		return -ENOTTY;
	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
		return -ENOTTY;
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	if (!mutex_trylock(&pm_mutex))
		return -EBUSY;

	lock_device_hotplug();
	data = filp->private_data;

	switch (cmd) {

	case SNAPSHOT_FREEZE:
		if (data->frozen)
			break;

		printk("Syncing filesystems ... ");
		sys_sync();
		printk("done.\n");

		error = freeze_processes();
		if (error)
			break;

		error = create_basic_memory_bitmaps();
		if (error)
			thaw_processes();
		else
			data->frozen = true;

		break;

	case SNAPSHOT_UNFREEZE:
		if (!data->frozen || data->ready)
			break;
		pm_restore_gfp_mask();
		free_basic_memory_bitmaps();
		data->free_bitmaps = false;
		thaw_processes();
		data->frozen = false;
		break;

	case SNAPSHOT_CREATE_IMAGE:
		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
			error = -EPERM;
			break;
		}
		pm_restore_gfp_mask();
		error = hibernation_snapshot(data->platform_support);
		if (!error) {
			error = put_user(in_suspend, (int __user *)arg);
			data->ready = !freezer_test_done && !error;
			freezer_test_done = false;
		}
		break;

	case SNAPSHOT_ATOMIC_RESTORE:
		snapshot_write_finalize(&data->handle);
		if (data->mode != O_WRONLY || !data->frozen ||
		    !snapshot_image_loaded(&data->handle)) {
			error = -EPERM;
			break;
		}
		error = hibernation_restore(data->platform_support);
		break;

	case SNAPSHOT_FREE:
		swsusp_free();
		memset(&data->handle, 0, sizeof(struct snapshot_handle));
		data->ready = false;
		/*
		 * It is necessary to thaw kernel threads here, because
		 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
		 * SNAPSHOT_FREE.  In that case, if kernel threads were not
		 * thawed, the preallocation of memory carried out by
		 * hibernation_snapshot() might run into problems (i.e. it
		 * might fail or even deadlock).
		 */
		thaw_kernel_threads();
		break;

	case SNAPSHOT_PREF_IMAGE_SIZE:
		image_size = arg;
		break;

	case SNAPSHOT_GET_IMAGE_SIZE:
		if (!data->ready) {
			error = -ENODATA;
			break;
		}
		size = snapshot_get_image_size();
		size <<= PAGE_SHIFT;
		error = put_user(size, (loff_t __user *)arg);
		break;

	case SNAPSHOT_AVAIL_SWAP_SIZE:
		size = count_swap_pages(data->swap, 1);
		size <<= PAGE_SHIFT;
		error = put_user(size, (loff_t __user *)arg);
		break;

	case SNAPSHOT_ALLOC_SWAP_PAGE:
		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
			error = -ENODEV;
			break;
		}
		offset = alloc_swapdev_block(data->swap);
		if (offset) {
			offset <<= PAGE_SHIFT;
			error = put_user(offset, (loff_t __user *)arg);
		} else {
			error = -ENOSPC;
		}
		break;

	case SNAPSHOT_FREE_SWAP_PAGES:
		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
			error = -ENODEV;
			break;
		}
		free_all_swap_pages(data->swap);
		break;

	case SNAPSHOT_S2RAM:
		if (!data->frozen) {
			error = -EPERM;
			break;
		}
		/*
		 * Tasks are frozen and the notifiers have been called with
		 * PM_HIBERNATION_PREPARE
		 */
		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
		data->ready = false;
		break;

	case SNAPSHOT_PLATFORM_SUPPORT:
		data->platform_support = !!arg;
		break;

	case SNAPSHOT_POWER_OFF:
		if (data->platform_support)
			error = hibernation_platform_enter();
		break;

	case SNAPSHOT_SET_SWAP_AREA:
		if (swsusp_swap_in_use()) {
			error = -EPERM;
		} else {
			struct resume_swap_area swap_area;
			dev_t swdev;

			error = copy_from_user(&swap_area, (void __user *)arg,
					sizeof(struct resume_swap_area));
			if (error) {
				error = -EFAULT;
				break;
			}

			/*
			 * User space encodes device types as two-byte values,
			 * so we need to recode them
			 */
			swdev = new_decode_dev(swap_area.dev);
			if (swdev) {
				offset = swap_area.offset;
				data->swap = swap_type_of(swdev, offset, NULL);
				if (data->swap < 0)
					error = -ENODEV;
			} else {
				data->swap = -1;
				error = -EINVAL;
			}
		}
		break;

	default:
		error = -ENOTTY;

	}

	unlock_device_hotplug();
	mutex_unlock(&pm_mutex);

	return error;
}

#ifdef CONFIG_COMPAT

struct compat_resume_swap_area {
	compat_loff_t offset;
	u32 dev;
} __packed;

static long
snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));

	switch (cmd) {
	case SNAPSHOT_GET_IMAGE_SIZE:
	case SNAPSHOT_AVAIL_SWAP_SIZE:
	case SNAPSHOT_ALLOC_SWAP_PAGE: {
		compat_loff_t __user *uoffset = compat_ptr(arg);
		loff_t offset;
		mm_segment_t old_fs;
		int err;

		old_fs = get_fs();
		set_fs(KERNEL_DS);
		err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
		set_fs(old_fs);
		if (!err && put_user(offset, uoffset))
			err = -EFAULT;
		return err;
	}

	case SNAPSHOT_CREATE_IMAGE:
		return snapshot_ioctl(file, cmd,
				      (unsigned long) compat_ptr(arg));

	case SNAPSHOT_SET_SWAP_AREA: {
		struct compat_resume_swap_area __user *u_swap_area =
			compat_ptr(arg);
		struct resume_swap_area swap_area;
		mm_segment_t old_fs;
		int err;

		err = get_user(swap_area.offset, &u_swap_area->offset);
		err |= get_user(swap_area.dev, &u_swap_area->dev);
		if (err)
			return -EFAULT;
		old_fs = get_fs();
		set_fs(KERNEL_DS);
		err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
				     (unsigned long) &swap_area);
		set_fs(old_fs);
		return err;
	}

	default:
		return snapshot_ioctl(file, cmd, arg);
	}
}

#endif /* CONFIG_COMPAT */

static const struct file_operations snapshot_fops = {
	.open = snapshot_open,
	.release = snapshot_release,
	.read = snapshot_read,
	.write = snapshot_write,
	.llseek = no_llseek,
	.unlocked_ioctl = snapshot_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = snapshot_compat_ioctl,
#endif
};

static struct miscdevice snapshot_device = {
	.minor = SNAPSHOT_MINOR,
	.name = "snapshot",
	.fops = &snapshot_fops,
};

static int __init snapshot_device_init(void)
{
	return misc_register(&snapshot_device);
};

device_initcall(snapshot_device_init);
Commit	Line	Data
6e1819d6 RW	1	/*
	2	* linux/kernel/power/user.c
	3	*
	4	* This file provides the user space interface for software suspend/resume.
	5	*
	6	* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
	7	*
	8	* This file is released under the GPLv2.
	9	*
	10	*/
	11
	12	#include <linux/suspend.h>
	13	#include <linux/syscalls.h>
3592695c	14	#include <linux/reboot.h>
6e1819d6 RW	15	#include <linux/string.h>
	16	#include <linux/device.h>
	17	#include <linux/miscdevice.h>
	18	#include <linux/mm.h>
	19	#include <linux/swap.h>
	20	#include <linux/swapops.h>
	21	#include <linux/pm.h>
	22	#include <linux/fs.h>
c336078b	23	#include <linux/compat.h>
97c7801c	24	#include <linux/console.h>
e3920fb4	25	#include <linux/cpu.h>
7dfb7103	26	#include <linux/freezer.h>
6e1819d6	27
7c0f6ba6	28	#include <linux/uaccess.h>
6e1819d6 RW	29
	30	#include "power.h"
	31
eb57c1cf	32
6e1819d6 RW	33	#define SNAPSHOT_MINOR 231
	34
	35	static struct snapshot_data {
	36	struct snapshot_handle handle;
	37	int swap;
6e1819d6	38	int mode;
7bc9b1cf RW	39	bool frozen;
	40	bool ready;
	41	bool platform_support;
aab17289	42	bool free_bitmaps;
6e1819d6 RW	43	} snapshot_state;
6e1819d6 RW	44
0709db60	45	atomic_t snapshot_device_available = ATOMIC_INIT(1);
6e1819d6 RW	46
	47	static int snapshot_open(struct inode inode, struct file filp)
	48	{
	49	struct snapshot_data *data;
ea00f4f4	50	int error, nr_calls = 0;
6e1819d6	51
a6e15a39 KC	52	if (!hibernation_available())
	53	return -EPERM;
	54
ba3256a4 MG	55	if (kernel_is_locked_down())
	56	return -EPERM;
	57
bcda53fa	58	lock_system_sleep();
25f2f3da RW	59
	60	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
	61	error = -EBUSY;
	62	goto Unlock;
	63	}
6e1819d6	64
1525a2ad	65	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
0709db60	66	atomic_inc(&snapshot_device_available);
25f2f3da RW	67	error = -ENOSYS;
25f2f3da RW	68	goto Unlock;
1525a2ad	69	}
6e1819d6 RW	70	nonseekable_open(inode, filp);
	71	data = &snapshot_state;
	72	filp->private_data = data;
	73	memset(&data->handle, 0, sizeof(struct snapshot_handle));
	74	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
c7510859	75	/* Hibernating. The image device should be accessible. */
915bae9e	76	data->swap = swsusp_resume_device ?
7bf23687	77	swap_type_of(swsusp_resume_device, 0, NULL) : -1;
6e1819d6	78	data->mode = O_RDONLY;
6a0c7cd3	79	data->free_bitmaps = false;
ea00f4f4	80	error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
c3e94d89	81	if (error)
ea00f4f4	82	__pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL);
6e1819d6	83	} else {
c7510859 RW	84	/*
	85	* Resuming. We may need to wait for the image device to
	86	* appear.
	87	*/
	88	wait_for_device_probe();
c7510859	89
6e1819d6 RW	90	data->swap = -1;
6e1819d6 RW	91	data->mode = O_WRONLY;
ea00f4f4	92	error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
aab17289 RW	93	if (!error) {
	94	error = create_basic_memory_bitmaps();
	95	data->free_bitmaps = !error;
ea00f4f4 LW	96	} else
	97	nr_calls--;
	98
c3e94d89	99	if (error)
ea00f4f4	100	__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
c3e94d89	101	}
8fd37a4c	102	if (error)
c3e94d89	103	atomic_inc(&snapshot_device_available);
8fd37a4c	104
7bc9b1cf RW	105	data->frozen = false;
	106	data->ready = false;
	107	data->platform_support = false;
6e1819d6	108
25f2f3da	109	Unlock:
bcda53fa	110	unlock_system_sleep();
25f2f3da RW	111
25f2f3da RW	112	return error;
6e1819d6 RW	113	}
	114
	115	static int snapshot_release(struct inode inode, struct file filp)
	116	{
	117	struct snapshot_data *data;
	118
bcda53fa	119	lock_system_sleep();
25f2f3da	120
6e1819d6 RW	121	swsusp_free();
6e1819d6 RW	122	data = filp->private_data;
d1d241cc	123	free_all_swap_pages(data->swap);
9744997a RW	124	if (data->frozen) {
9744997a RW	125	pm_restore_gfp_mask();
8fd37a4c	126	free_basic_memory_bitmaps();
6e1819d6	127	thaw_processes();
aab17289 RW	128	} else if (data->free_bitmaps) {
aab17289 RW	129	free_basic_memory_bitmaps();
9744997a	130	}
1497dd1d	131	pm_notifier_call_chain(data->mode == O_RDONLY ?
c3e94d89	132	PM_POST_HIBERNATION : PM_POST_RESTORE);
0709db60	133	atomic_inc(&snapshot_device_available);
25f2f3da	134
bcda53fa	135	unlock_system_sleep();
25f2f3da	136
6e1819d6 RW	137	return 0;
	138	}
	139
	140	static ssize_t snapshot_read(struct file filp, char __user buf,
	141	size_t count, loff_t *offp)
	142	{
	143	struct snapshot_data *data;
	144	ssize_t res;
d3c1b24c	145	loff_t pg_offp = *offp & ~PAGE_MASK;
6e1819d6	146
bcda53fa	147	lock_system_sleep();
25f2f3da	148
6e1819d6	149	data = filp->private_data;
25f2f3da RW	150	if (!data->ready) {
	151	res = -ENODATA;
	152	goto Unlock;
	153	}
d3c1b24c JS	154	if (!pg_offp) { /* on page boundary? */
	155	res = snapshot_read_next(&data->handle);
	156	if (res <= 0)
	157	goto Unlock;
	158	} else {
	159	res = PAGE_SIZE - pg_offp;
6e1819d6	160	}
25f2f3da	161
d3c1b24c JS	162	res = simple_read_from_buffer(buf, count, &pg_offp,
	163	data_of(data->handle), res);
	164	if (res > 0)
	165	*offp += res;
	166
25f2f3da	167	Unlock:
bcda53fa	168	unlock_system_sleep();
25f2f3da	169
6e1819d6 RW	170	return res;
	171	}
	172
	173	static ssize_t snapshot_write(struct file filp, const char __user buf,
	174	size_t count, loff_t *offp)
	175	{
	176	struct snapshot_data *data;
	177	ssize_t res;
d3c1b24c	178	loff_t pg_offp = *offp & ~PAGE_MASK;
6e1819d6	179
bcda53fa	180	lock_system_sleep();
25f2f3da	181
6e1819d6	182	data = filp->private_data;
d3c1b24c JS	183
	184	if (!pg_offp) {
	185	res = snapshot_write_next(&data->handle);
	186	if (res <= 0)
	187	goto unlock;
	188	} else {
	189	res = PAGE_SIZE - pg_offp;
6e1819d6	190	}
25f2f3da	191
d3c1b24c JS	192	res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
	193	buf, count);
	194	if (res > 0)
	195	*offp += res;
	196	unlock:
bcda53fa	197	unlock_system_sleep();
25f2f3da	198
6e1819d6 RW	199	return res;
	200	}
	201
52d11025 AC	202	static long snapshot_ioctl(struct file *filp, unsigned int cmd,
52d11025 AC	203	unsigned long arg)
6e1819d6 RW	204	{
	205	int error = 0;
	206	struct snapshot_data *data;
af508b34	207	loff_t size;
3aef83e0	208	sector_t offset;
6e1819d6 RW	209
	210	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
	211	return -ENOTTY;
	212	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
	213	return -ENOTTY;
	214	if (!capable(CAP_SYS_ADMIN))
	215	return -EPERM;
	216
25f2f3da RW	217	if (!mutex_trylock(&pm_mutex))
25f2f3da RW	218	return -EBUSY;
6e1819d6	219
942f4015	220	lock_device_hotplug();
25f2f3da	221	data = filp->private_data;
52d11025	222
6e1819d6 RW	223	switch (cmd) {
	224
	225	case SNAPSHOT_FREEZE:
	226	if (data->frozen)
	227	break;
1bfcf130	228
c3e94d89 AS	229	printk("Syncing filesystems ... ");
	230	sys_sync();
	231	printk("done.\n");
	232
1bfcf130	233	error = freeze_processes();
8fd37a4c RW	234	if (error)
	235	break;
	236
	237	error = create_basic_memory_bitmaps();
	238	if (error)
	239	thaw_processes();
	240	else
7bc9b1cf	241	data->frozen = true;
8fd37a4c	242
6e1819d6 RW	243	break;
	244
	245	case SNAPSHOT_UNFREEZE:
2f41dddb	246	if (!data->frozen \|\| data->ready)
6e1819d6	247	break;
c9e664f1	248	pm_restore_gfp_mask();
8fd37a4c	249	free_basic_memory_bitmaps();
aab17289	250	data->free_bitmaps = false;
6e1819d6	251	thaw_processes();
7bc9b1cf	252	data->frozen = false;
6e1819d6 RW	253	break;
6e1819d6 RW	254
b694e52e	255	case SNAPSHOT_CREATE_IMAGE:
6e1819d6 RW	256	if (data->mode != O_RDONLY \|\| !data->frozen \|\| data->ready) {
	257	error = -EPERM;
	258	break;
	259	}
c9e664f1	260	pm_restore_gfp_mask();
eb57c1cf	261	error = hibernation_snapshot(data->platform_support);
51d6ff7a	262	if (!error) {
cc5d207c	263	error = put_user(in_suspend, (int __user *)arg);
a556d5b5 SB	264	data->ready = !freezer_test_done && !error;
a556d5b5 SB	265	freezer_test_done = false;
97819a26	266	}
6e1819d6 RW	267	break;
	268
	269	case SNAPSHOT_ATOMIC_RESTORE:
8357376d	270	snapshot_write_finalize(&data->handle);
6e1819d6 RW	271	if (data->mode != O_WRONLY \|\| !data->frozen \|\|
	272	!snapshot_image_loaded(&data->handle)) {
	273	error = -EPERM;
	274	break;
	275	}
eb57c1cf	276	error = hibernation_restore(data->platform_support);
6e1819d6 RW	277	break;
	278
	279	case SNAPSHOT_FREE:
	280	swsusp_free();
	281	memset(&data->handle, 0, sizeof(struct snapshot_handle));
7bc9b1cf	282	data->ready = false;
181e9bde RW	283	/*
	284	* It is necessary to thaw kernel threads here, because
	285	* SNAPSHOT_CREATE_IMAGE may be invoked directly after
	286	* SNAPSHOT_FREE. In that case, if kernel threads were not
	287	* thawed, the preallocation of memory carried out by
	288	* hibernation_snapshot() might run into problems (i.e. it
	289	* might fail or even deadlock).
	290	*/
	291	thaw_kernel_threads();
6e1819d6 RW	292	break;
6e1819d6 RW	293
b694e52e	294	case SNAPSHOT_PREF_IMAGE_SIZE:
6e1819d6 RW	295	image_size = arg;
	296	break;
	297
af508b34 RW	298	case SNAPSHOT_GET_IMAGE_SIZE:
	299	if (!data->ready) {
	300	error = -ENODATA;
	301	break;
	302	}
	303	size = snapshot_get_image_size();
	304	size <<= PAGE_SHIFT;
	305	error = put_user(size, (loff_t __user *)arg);
	306	break;
	307
b694e52e	308	case SNAPSHOT_AVAIL_SWAP_SIZE:
af508b34 RW	309	size = count_swap_pages(data->swap, 1);
	310	size <<= PAGE_SHIFT;
	311	error = put_user(size, (loff_t __user *)arg);
6e1819d6 RW	312	break;
6e1819d6 RW	313
b694e52e	314	case SNAPSHOT_ALLOC_SWAP_PAGE:
6e1819d6 RW	315	if (data->swap < 0 \|\| data->swap >= MAX_SWAPFILES) {
	316	error = -ENODEV;
	317	break;
	318	}
d1d241cc	319	offset = alloc_swapdev_block(data->swap);
6e1819d6 RW	320	if (offset) {
6e1819d6 RW	321	offset <<= PAGE_SHIFT;
cc5d207c	322	error = put_user(offset, (loff_t __user *)arg);
6e1819d6 RW	323	} else {
	324	error = -ENOSPC;
	325	}
	326	break;
	327
	328	case SNAPSHOT_FREE_SWAP_PAGES:
	329	if (data->swap < 0 \|\| data->swap >= MAX_SWAPFILES) {
	330	error = -ENODEV;
	331	break;
	332	}
d1d241cc	333	free_all_swap_pages(data->swap);
6e1819d6 RW	334	break;
6e1819d6 RW	335
9b238205 LT	336	case SNAPSHOT_S2RAM:
	337	if (!data->frozen) {
	338	error = -EPERM;
	339	break;
	340	}
6c961dfb RW	341	/*
	342	* Tasks are frozen and the notifiers have been called with
	343	* PM_HIBERNATION_PREPARE
	344	*/
	345	error = suspend_devices_and_enter(PM_SUSPEND_MEM);
7bc9b1cf	346	data->ready = false;
9b238205 LT	347	break;
9b238205 LT	348
eb57c1cf RW	349	case SNAPSHOT_PLATFORM_SUPPORT:
	350	data->platform_support = !!arg;
	351	break;
	352
	353	case SNAPSHOT_POWER_OFF:
	354	if (data->platform_support)
	355	error = hibernation_platform_enter();
	356	break;
	357
37b2ba12	358	case SNAPSHOT_SET_SWAP_AREA:
d1d241cc	359	if (swsusp_swap_in_use()) {
37b2ba12 RW	360	error = -EPERM;
	361	} else {
	362	struct resume_swap_area swap_area;
	363	dev_t swdev;
	364
	365	error = copy_from_user(&swap_area, (void __user *)arg,
	366	sizeof(struct resume_swap_area));
	367	if (error) {
	368	error = -EFAULT;
	369	break;
	370	}
	371
	372	/*
	373	* User space encodes device types as two-byte values,
	374	* so we need to recode them
	375	*/
d88d4050	376	swdev = new_decode_dev(swap_area.dev);
37b2ba12 RW	377	if (swdev) {
37b2ba12 RW	378	offset = swap_area.offset;
7bf23687	379	data->swap = swap_type_of(swdev, offset, NULL);
37b2ba12 RW	380	if (data->swap < 0)
	381	error = -ENODEV;
	382	} else {
	383	data->swap = -1;
	384	error = -EINVAL;
	385	}
	386	}
	387	break;
	388
6e1819d6 RW	389	default:
	390	error = -ENOTTY;
	391
	392	}
25f2f3da	393
942f4015	394	unlock_device_hotplug();
25f2f3da RW	395	mutex_unlock(&pm_mutex);
25f2f3da RW	396
6e1819d6 RW	397	return error;
	398	}
	399
c336078b BH	400	#ifdef CONFIG_COMPAT
	401
	402	struct compat_resume_swap_area {
	403	compat_loff_t offset;
	404	u32 dev;
	405	} __packed;
	406
	407	static long
	408	snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	409	{
	410	BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
	411
	412	switch (cmd) {
	413	case SNAPSHOT_GET_IMAGE_SIZE:
	414	case SNAPSHOT_AVAIL_SWAP_SIZE:
	415	case SNAPSHOT_ALLOC_SWAP_PAGE: {
	416	compat_loff_t __user *uoffset = compat_ptr(arg);
	417	loff_t offset;
	418	mm_segment_t old_fs;
	419	int err;
	420
	421	old_fs = get_fs();
	422	set_fs(KERNEL_DS);
	423	err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
	424	set_fs(old_fs);
	425	if (!err && put_user(offset, uoffset))
	426	err = -EFAULT;
	427	return err;
	428	}
	429
	430	case SNAPSHOT_CREATE_IMAGE:
	431	return snapshot_ioctl(file, cmd,
	432	(unsigned long) compat_ptr(arg));
	433
	434	case SNAPSHOT_SET_SWAP_AREA: {
	435	struct compat_resume_swap_area __user *u_swap_area =
	436	compat_ptr(arg);
	437	struct resume_swap_area swap_area;
	438	mm_segment_t old_fs;
	439	int err;
	440
	441	err = get_user(swap_area.offset, &u_swap_area->offset);
	442	err \|= get_user(swap_area.dev, &u_swap_area->dev);
	443	if (err)
	444	return -EFAULT;
	445	old_fs = get_fs();
	446	set_fs(KERNEL_DS);
	447	err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
	448	(unsigned long) &swap_area);
	449	set_fs(old_fs);
	450	return err;
	451	}
	452
	453	default:
	454	return snapshot_ioctl(file, cmd, arg);
	455	}
	456	}
	457
	458	#endif /* CONFIG_COMPAT */
	459
15ad7cdc	460	static const struct file_operations snapshot_fops = {
6e1819d6 RW	461	.open = snapshot_open,
	462	.release = snapshot_release,
	463	.read = snapshot_read,
	464	.write = snapshot_write,
	465	.llseek = no_llseek,
52d11025	466	.unlocked_ioctl = snapshot_ioctl,
c336078b BH	467	#ifdef CONFIG_COMPAT
	468	.compat_ioctl = snapshot_compat_ioctl,
	469	#endif
6e1819d6 RW	470	};
	471
	472	static struct miscdevice snapshot_device = {
	473	.minor = SNAPSHOT_MINOR,
	474	.name = "snapshot",
	475	.fops = &snapshot_fops,
	476	};
	477
	478	static int __init snapshot_device_init(void)
	479	{
	480	return misc_register(&snapshot_device);
	481	};
	482
	483	device_initcall(snapshot_device_init);