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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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>
 */

#include <linux/suspend.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"


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

int is_hibernate_resume_dev(dev_t dev)
{
	return hibernation_available() && snapshot_state.dev == dev;
}

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

	if (!hibernation_available())
		return -EPERM;

	lock_system_sleep();

	if (!hibernate_acquire()) {
		error = -EBUSY;
		goto Unlock;
	}

	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
		hibernate_release();
		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 = swap_type_of(swsusp_resume_device, 0);
		data->mode = O_RDONLY;
		data->free_bitmaps = false;
		error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
	} 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_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
		if (!error) {
			error = create_basic_memory_bitmaps();
			data->free_bitmaps = !error;
		}
	}
	if (error)
		hibernate_release();

	data->frozen = false;
	data->ready = false;
	data->platform_support = false;
	data->dev = 0;

 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;
	data->dev = 0;
	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);
	hibernate_release();

	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;
	}

	if (!data_of(data->handle)) {
		res = -EINVAL;
		goto unlock;
	}

	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;
}

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

static int snapshot_set_swap_area(struct snapshot_data *data,
		void __user *argp)
{
	sector_t offset;
	dev_t swdev;

	if (swsusp_swap_in_use())
		return -EPERM;

	if (in_compat_syscall()) {
		struct compat_resume_swap_area swap_area;

		if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
			return -EFAULT;
		swdev = new_decode_dev(swap_area.dev);
		offset = swap_area.offset;
	} else {
		struct resume_swap_area swap_area;

		if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
			return -EFAULT;
		swdev = new_decode_dev(swap_area.dev);
		offset = swap_area.offset;
	}

	/*
	 * User space encodes device types as two-byte values,
	 * so we need to recode them
	 */
	data->swap = swap_type_of(swdev, offset);
	if (data->swap < 0)
		return swdev ? -ENODEV : -EINVAL;
	data->dev = swdev;
	return 0;
}

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(&system_transition_mutex))
		return -EBUSY;

	lock_device_hotplug();
	data = filp->private_data;

	switch (cmd) {

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

		ksys_sync_helper();

		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:
		error = snapshot_set_swap_area(data, (void __user *)arg);
		break;

	default:
		error = -ENOTTY;

	}

	unlock_device_hotplug();
	mutex_unlock(&system_transition_mutex);

	return error;
}

#ifdef CONFIG_COMPAT
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:
	case SNAPSHOT_CREATE_IMAGE:
	case SNAPSHOT_SET_SWAP_AREA:
		return snapshot_ioctl(file, cmd,
				      (unsigned long) compat_ptr(arg));
	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
55716d26	1	// SPDX-License-Identifier: GPL-2.0-only
6e1819d6 RW	2	/*
	3	* linux/kernel/power/user.c
	4	*
	5	* This file provides the user space interface for software suspend/resume.
	6	*
	7	* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
6e1819d6 RW	8	*/
	9
	10	#include <linux/suspend.h>
3592695c	11	#include <linux/reboot.h>
6e1819d6 RW	12	#include <linux/string.h>
	13	#include <linux/device.h>
	14	#include <linux/miscdevice.h>
	15	#include <linux/mm.h>
	16	#include <linux/swap.h>
	17	#include <linux/swapops.h>
	18	#include <linux/pm.h>
	19	#include <linux/fs.h>
c336078b	20	#include <linux/compat.h>
97c7801c	21	#include <linux/console.h>
e3920fb4	22	#include <linux/cpu.h>
7dfb7103	23	#include <linux/freezer.h>
6e1819d6	24
7c0f6ba6	25	#include <linux/uaccess.h>
6e1819d6 RW	26
	27	#include "power.h"
	28
eb57c1cf	29
6e1819d6 RW	30	static struct snapshot_data {
	31	struct snapshot_handle handle;
	32	int swap;
6e1819d6	33	int mode;
7bc9b1cf RW	34	bool frozen;
	35	bool ready;
	36	bool platform_support;
aab17289	37	bool free_bitmaps;
bb3247a3	38	dev_t dev;
6e1819d6 RW	39	} snapshot_state;
6e1819d6 RW	40
bb3247a3	41	int is_hibernate_resume_dev(dev_t dev)
ad1e4f74	42	{
bb3247a3	43	return hibernation_available() && snapshot_state.dev == dev;
ad1e4f74 DA	44	}
ad1e4f74 DA	45
6e1819d6 RW	46	static int snapshot_open(struct inode inode, struct file filp)
	47	{
	48	struct snapshot_data *data;
70d93298	49	int error;
6e1819d6	50
a6e15a39 KC	51	if (!hibernation_available())
	52	return -EPERM;
	53
bcda53fa	54	lock_system_sleep();
25f2f3da	55
ab7e9b06	56	if (!hibernate_acquire()) {
25f2f3da RW	57	error = -EBUSY;
	58	goto Unlock;
	59	}
6e1819d6	60
1525a2ad	61	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
ab7e9b06	62	hibernate_release();
25f2f3da RW	63	error = -ENOSYS;
25f2f3da RW	64	goto Unlock;
1525a2ad	65	}
6e1819d6 RW	66	nonseekable_open(inode, filp);
	67	data = &snapshot_state;
	68	filp->private_data = data;
	69	memset(&data->handle, 0, sizeof(struct snapshot_handle));
	70	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
c7510859	71	/* Hibernating. The image device should be accessible. */
21bd9005	72	data->swap = swap_type_of(swsusp_resume_device, 0);
6e1819d6	73	data->mode = O_RDONLY;
6a0c7cd3	74	data->free_bitmaps = false;
70d93298	75	error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
6e1819d6	76	} else {
c7510859 RW	77	/*
	78	* Resuming. We may need to wait for the image device to
	79	* appear.
	80	*/
	81	wait_for_device_probe();
c7510859	82
6e1819d6 RW	83	data->swap = -1;
6e1819d6 RW	84	data->mode = O_WRONLY;
70d93298	85	error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
aab17289 RW	86	if (!error) {
	87	error = create_basic_memory_bitmaps();
	88	data->free_bitmaps = !error;
70d93298	89	}
c3e94d89	90	}
8fd37a4c	91	if (error)
ab7e9b06	92	hibernate_release();
8fd37a4c	93
7bc9b1cf RW	94	data->frozen = false;
	95	data->ready = false;
	96	data->platform_support = false;
bb3247a3	97	data->dev = 0;
6e1819d6	98
25f2f3da	99	Unlock:
bcda53fa	100	unlock_system_sleep();
25f2f3da RW	101
25f2f3da RW	102	return error;
6e1819d6 RW	103	}
	104
	105	static int snapshot_release(struct inode inode, struct file filp)
	106	{
	107	struct snapshot_data *data;
	108
bcda53fa	109	lock_system_sleep();
25f2f3da	110
6e1819d6 RW	111	swsusp_free();
6e1819d6 RW	112	data = filp->private_data;
bb3247a3	113	data->dev = 0;
d1d241cc	114	free_all_swap_pages(data->swap);
9744997a RW	115	if (data->frozen) {
9744997a RW	116	pm_restore_gfp_mask();
8fd37a4c	117	free_basic_memory_bitmaps();
6e1819d6	118	thaw_processes();
aab17289 RW	119	} else if (data->free_bitmaps) {
aab17289 RW	120	free_basic_memory_bitmaps();
9744997a	121	}
1497dd1d	122	pm_notifier_call_chain(data->mode == O_RDONLY ?
c3e94d89	123	PM_POST_HIBERNATION : PM_POST_RESTORE);
ab7e9b06	124	hibernate_release();
25f2f3da	125
bcda53fa	126	unlock_system_sleep();
25f2f3da	127
6e1819d6 RW	128	return 0;
	129	}
	130
	131	static ssize_t snapshot_read(struct file filp, char __user buf,
	132	size_t count, loff_t *offp)
	133	{
	134	struct snapshot_data *data;
	135	ssize_t res;
d3c1b24c	136	loff_t pg_offp = *offp & ~PAGE_MASK;
6e1819d6	137
bcda53fa	138	lock_system_sleep();
25f2f3da	139
6e1819d6	140	data = filp->private_data;
25f2f3da RW	141	if (!data->ready) {
	142	res = -ENODATA;
	143	goto Unlock;
	144	}
d3c1b24c JS	145	if (!pg_offp) { /* on page boundary? */
	146	res = snapshot_read_next(&data->handle);
	147	if (res <= 0)
	148	goto Unlock;
	149	} else {
	150	res = PAGE_SIZE - pg_offp;
6e1819d6	151	}
25f2f3da	152
d3c1b24c JS	153	res = simple_read_from_buffer(buf, count, &pg_offp,
	154	data_of(data->handle), res);
	155	if (res > 0)
	156	*offp += res;
	157
25f2f3da	158	Unlock:
bcda53fa	159	unlock_system_sleep();
25f2f3da	160
6e1819d6 RW	161	return res;
	162	}
	163
	164	static ssize_t snapshot_write(struct file filp, const char __user buf,
	165	size_t count, loff_t *offp)
	166	{
	167	struct snapshot_data *data;
	168	ssize_t res;
d3c1b24c	169	loff_t pg_offp = *offp & ~PAGE_MASK;
6e1819d6	170
bcda53fa	171	lock_system_sleep();
25f2f3da	172
6e1819d6	173	data = filp->private_data;
d3c1b24c JS	174
	175	if (!pg_offp) {
	176	res = snapshot_write_next(&data->handle);
	177	if (res <= 0)
	178	goto unlock;
	179	} else {
	180	res = PAGE_SIZE - pg_offp;
6e1819d6	181	}
25f2f3da	182
fc14eebf TH	183	if (!data_of(data->handle)) {
	184	res = -EINVAL;
	185	goto unlock;
	186	}
	187
d3c1b24c JS	188	res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
	189	buf, count);
	190	if (res > 0)
	191	*offp += res;
	192	unlock:
bcda53fa	193	unlock_system_sleep();
25f2f3da	194
6e1819d6 RW	195	return res;
	196	}
	197
0f5c4c6e CH	198	struct compat_resume_swap_area {
	199	compat_loff_t offset;
	200	u32 dev;
	201	} __packed;
	202
88a77559 CH	203	static int snapshot_set_swap_area(struct snapshot_data *data,
	204	void __user *argp)
	205	{
88a77559 CH	206	sector_t offset;
	207	dev_t swdev;
	208
	209	if (swsusp_swap_in_use())
	210	return -EPERM;
0f5c4c6e CH	211
	212	if (in_compat_syscall()) {
	213	struct compat_resume_swap_area swap_area;
	214
	215	if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
	216	return -EFAULT;
	217	swdev = new_decode_dev(swap_area.dev);
	218	offset = swap_area.offset;
	219	} else {
	220	struct resume_swap_area swap_area;
	221
	222	if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
	223	return -EFAULT;
	224	swdev = new_decode_dev(swap_area.dev);
	225	offset = swap_area.offset;
	226	}
88a77559 CH	227
	228	/*
	229	* User space encodes device types as two-byte values,
	230	* so we need to recode them
	231	*/
21bd9005	232	data->swap = swap_type_of(swdev, offset);
88a77559	233	if (data->swap < 0)
21bd9005 CH	234	return swdev ? -ENODEV : -EINVAL;
21bd9005 CH	235	data->dev = swdev;
88a77559 CH	236	return 0;
	237	}
	238
52d11025 AC	239	static long snapshot_ioctl(struct file *filp, unsigned int cmd,
52d11025 AC	240	unsigned long arg)
6e1819d6 RW	241	{
	242	int error = 0;
	243	struct snapshot_data *data;
af508b34	244	loff_t size;
3aef83e0	245	sector_t offset;
6e1819d6 RW	246
	247	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
	248	return -ENOTTY;
	249	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
	250	return -ENOTTY;
	251	if (!capable(CAP_SYS_ADMIN))
	252	return -EPERM;
	253
55f2503c	254	if (!mutex_trylock(&system_transition_mutex))
25f2f3da	255	return -EBUSY;
6e1819d6	256
942f4015	257	lock_device_hotplug();
25f2f3da	258	data = filp->private_data;
52d11025	259
6e1819d6 RW	260	switch (cmd) {
	261
	262	case SNAPSHOT_FREEZE:
	263	if (data->frozen)
	264	break;
1bfcf130	265
b5dee313	266	ksys_sync_helper();
c3e94d89	267
1bfcf130	268	error = freeze_processes();
8fd37a4c RW	269	if (error)
	270	break;
	271
	272	error = create_basic_memory_bitmaps();
	273	if (error)
	274	thaw_processes();
	275	else
7bc9b1cf	276	data->frozen = true;
8fd37a4c	277
6e1819d6 RW	278	break;
	279
	280	case SNAPSHOT_UNFREEZE:
2f41dddb	281	if (!data->frozen \|\| data->ready)
6e1819d6	282	break;
c9e664f1	283	pm_restore_gfp_mask();
8fd37a4c	284	free_basic_memory_bitmaps();
aab17289	285	data->free_bitmaps = false;
6e1819d6	286	thaw_processes();
7bc9b1cf	287	data->frozen = false;
6e1819d6 RW	288	break;
6e1819d6 RW	289
b694e52e	290	case SNAPSHOT_CREATE_IMAGE:
6e1819d6 RW	291	if (data->mode != O_RDONLY \|\| !data->frozen \|\| data->ready) {
	292	error = -EPERM;
	293	break;
	294	}
c9e664f1	295	pm_restore_gfp_mask();
eb57c1cf	296	error = hibernation_snapshot(data->platform_support);
51d6ff7a	297	if (!error) {
cc5d207c	298	error = put_user(in_suspend, (int __user *)arg);
a556d5b5 SB	299	data->ready = !freezer_test_done && !error;
a556d5b5 SB	300	freezer_test_done = false;
97819a26	301	}
6e1819d6 RW	302	break;
	303
	304	case SNAPSHOT_ATOMIC_RESTORE:
8357376d	305	snapshot_write_finalize(&data->handle);
6e1819d6 RW	306	if (data->mode != O_WRONLY \|\| !data->frozen \|\|
	307	!snapshot_image_loaded(&data->handle)) {
	308	error = -EPERM;
	309	break;
	310	}
eb57c1cf	311	error = hibernation_restore(data->platform_support);
6e1819d6 RW	312	break;
	313
	314	case SNAPSHOT_FREE:
	315	swsusp_free();
	316	memset(&data->handle, 0, sizeof(struct snapshot_handle));
7bc9b1cf	317	data->ready = false;
181e9bde RW	318	/*
	319	* It is necessary to thaw kernel threads here, because
	320	* SNAPSHOT_CREATE_IMAGE may be invoked directly after
	321	* SNAPSHOT_FREE. In that case, if kernel threads were not
	322	* thawed, the preallocation of memory carried out by
	323	* hibernation_snapshot() might run into problems (i.e. it
	324	* might fail or even deadlock).
	325	*/
	326	thaw_kernel_threads();
6e1819d6 RW	327	break;
6e1819d6 RW	328
b694e52e	329	case SNAPSHOT_PREF_IMAGE_SIZE:
6e1819d6 RW	330	image_size = arg;
	331	break;
	332
af508b34 RW	333	case SNAPSHOT_GET_IMAGE_SIZE:
	334	if (!data->ready) {
	335	error = -ENODATA;
	336	break;
	337	}
	338	size = snapshot_get_image_size();
	339	size <<= PAGE_SHIFT;
	340	error = put_user(size, (loff_t __user *)arg);
	341	break;
	342
b694e52e	343	case SNAPSHOT_AVAIL_SWAP_SIZE:
af508b34 RW	344	size = count_swap_pages(data->swap, 1);
	345	size <<= PAGE_SHIFT;
	346	error = put_user(size, (loff_t __user *)arg);
6e1819d6 RW	347	break;
6e1819d6 RW	348
b694e52e	349	case SNAPSHOT_ALLOC_SWAP_PAGE:
6e1819d6 RW	350	if (data->swap < 0 \|\| data->swap >= MAX_SWAPFILES) {
	351	error = -ENODEV;
	352	break;
	353	}
d1d241cc	354	offset = alloc_swapdev_block(data->swap);
6e1819d6 RW	355	if (offset) {
6e1819d6 RW	356	offset <<= PAGE_SHIFT;
cc5d207c	357	error = put_user(offset, (loff_t __user *)arg);
6e1819d6 RW	358	} else {
	359	error = -ENOSPC;
	360	}
	361	break;
	362
	363	case SNAPSHOT_FREE_SWAP_PAGES:
	364	if (data->swap < 0 \|\| data->swap >= MAX_SWAPFILES) {
	365	error = -ENODEV;
	366	break;
	367	}
d1d241cc	368	free_all_swap_pages(data->swap);
6e1819d6 RW	369	break;
6e1819d6 RW	370
9b238205 LT	371	case SNAPSHOT_S2RAM:
	372	if (!data->frozen) {
	373	error = -EPERM;
	374	break;
	375	}
6c961dfb RW	376	/*
	377	* Tasks are frozen and the notifiers have been called with
	378	* PM_HIBERNATION_PREPARE
	379	*/
	380	error = suspend_devices_and_enter(PM_SUSPEND_MEM);
7bc9b1cf	381	data->ready = false;
9b238205 LT	382	break;
9b238205 LT	383
eb57c1cf RW	384	case SNAPSHOT_PLATFORM_SUPPORT:
	385	data->platform_support = !!arg;
	386	break;
	387
	388	case SNAPSHOT_POWER_OFF:
	389	if (data->platform_support)
	390	error = hibernation_platform_enter();
	391	break;
	392
37b2ba12	393	case SNAPSHOT_SET_SWAP_AREA:
88a77559	394	error = snapshot_set_swap_area(data, (void __user *)arg);
37b2ba12 RW	395	break;
37b2ba12 RW	396
6e1819d6 RW	397	default:
	398	error = -ENOTTY;
	399
	400	}
25f2f3da	401
942f4015	402	unlock_device_hotplug();
55f2503c	403	mutex_unlock(&system_transition_mutex);
25f2f3da	404
6e1819d6 RW	405	return error;
	406	}
	407
c336078b	408	#ifdef CONFIG_COMPAT
c336078b BH	409	static long
	410	snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	411	{
	412	BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
	413
	414	switch (cmd) {
	415	case SNAPSHOT_GET_IMAGE_SIZE:
	416	case SNAPSHOT_AVAIL_SWAP_SIZE:
fba616a4	417	case SNAPSHOT_ALLOC_SWAP_PAGE:
c336078b	418	case SNAPSHOT_CREATE_IMAGE:
0f5c4c6e	419	case SNAPSHOT_SET_SWAP_AREA:
c336078b BH	420	return snapshot_ioctl(file, cmd,
c336078b BH	421	(unsigned long) compat_ptr(arg));
c336078b BH	422	default:
	423	return snapshot_ioctl(file, cmd, arg);
	424	}
	425	}
c336078b BH	426	#endif /* CONFIG_COMPAT */
c336078b BH	427
15ad7cdc	428	static const struct file_operations snapshot_fops = {
6e1819d6 RW	429	.open = snapshot_open,
	430	.release = snapshot_release,
	431	.read = snapshot_read,
	432	.write = snapshot_write,
	433	.llseek = no_llseek,
52d11025	434	.unlocked_ioctl = snapshot_ioctl,
c336078b BH	435	#ifdef CONFIG_COMPAT
	436	.compat_ioctl = snapshot_compat_ioctl,
	437	#endif
6e1819d6 RW	438	};
	439
	440	static struct miscdevice snapshot_device = {
	441	.minor = SNAPSHOT_MINOR,
	442	.name = "snapshot",
	443	.fops = &snapshot_fops,
	444	};
	445
	446	static int __init snapshot_device_init(void)
	447	{
	448	return misc_register(&snapshot_device);
	449	};
	450
	451	device_initcall(snapshot_device_init);