2 * linux/kernel/power/user.c
4 * This file provides the user space interface for software suspend/resume.
6 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
8 * This file is released under the GPLv2.
12 #include <linux/suspend.h>
13 #include <linux/syscalls.h>
14 #include <linux/reboot.h>
15 #include <linux/string.h>
16 #include <linux/device.h>
17 #include <linux/miscdevice.h>
19 #include <linux/swap.h>
20 #include <linux/swapops.h>
23 #include <linux/compat.h>
24 #include <linux/console.h>
25 #include <linux/cpu.h>
26 #include <linux/freezer.h>
28 #include <asm/uaccess.h>
33 #define SNAPSHOT_MINOR 231
35 static struct snapshot_data
{
36 struct snapshot_handle handle
;
41 char platform_support
;
44 atomic_t snapshot_device_available
= ATOMIC_INIT(1);
46 static int snapshot_open(struct inode
*inode
, struct file
*filp
)
48 struct snapshot_data
*data
;
53 if (!atomic_add_unless(&snapshot_device_available
, -1, 0)) {
58 if ((filp
->f_flags
& O_ACCMODE
) == O_RDWR
) {
59 atomic_inc(&snapshot_device_available
);
63 nonseekable_open(inode
, filp
);
64 data
= &snapshot_state
;
65 filp
->private_data
= data
;
66 memset(&data
->handle
, 0, sizeof(struct snapshot_handle
));
67 if ((filp
->f_flags
& O_ACCMODE
) == O_RDONLY
) {
68 /* Hibernating. The image device should be accessible. */
69 data
->swap
= swsusp_resume_device
?
70 swap_type_of(swsusp_resume_device
, 0, NULL
) : -1;
71 data
->mode
= O_RDONLY
;
72 error
= pm_notifier_call_chain(PM_HIBERNATION_PREPARE
);
74 pm_notifier_call_chain(PM_POST_HIBERNATION
);
77 * Resuming. We may need to wait for the image device to
80 wait_for_device_probe();
83 data
->mode
= O_WRONLY
;
84 error
= pm_notifier_call_chain(PM_RESTORE_PREPARE
);
86 pm_notifier_call_chain(PM_POST_RESTORE
);
89 atomic_inc(&snapshot_device_available
);
93 data
->platform_support
= 0;
96 unlock_system_sleep();
101 static int snapshot_release(struct inode
*inode
, struct file
*filp
)
103 struct snapshot_data
*data
;
108 data
= filp
->private_data
;
109 free_all_swap_pages(data
->swap
);
111 pm_restore_gfp_mask();
112 free_basic_memory_bitmaps();
115 pm_notifier_call_chain(data
->mode
== O_RDONLY
?
116 PM_POST_HIBERNATION
: PM_POST_RESTORE
);
117 atomic_inc(&snapshot_device_available
);
119 unlock_system_sleep();
124 static ssize_t
snapshot_read(struct file
*filp
, char __user
*buf
,
125 size_t count
, loff_t
*offp
)
127 struct snapshot_data
*data
;
129 loff_t pg_offp
= *offp
& ~PAGE_MASK
;
133 data
= filp
->private_data
;
138 if (!pg_offp
) { /* on page boundary? */
139 res
= snapshot_read_next(&data
->handle
);
143 res
= PAGE_SIZE
- pg_offp
;
146 res
= simple_read_from_buffer(buf
, count
, &pg_offp
,
147 data_of(data
->handle
), res
);
152 unlock_system_sleep();
157 static ssize_t
snapshot_write(struct file
*filp
, const char __user
*buf
,
158 size_t count
, loff_t
*offp
)
160 struct snapshot_data
*data
;
162 loff_t pg_offp
= *offp
& ~PAGE_MASK
;
166 data
= filp
->private_data
;
169 res
= snapshot_write_next(&data
->handle
);
173 res
= PAGE_SIZE
- pg_offp
;
176 res
= simple_write_to_buffer(data_of(data
->handle
), res
, &pg_offp
,
181 unlock_system_sleep();
186 static long snapshot_ioctl(struct file
*filp
, unsigned int cmd
,
190 struct snapshot_data
*data
;
194 if (_IOC_TYPE(cmd
) != SNAPSHOT_IOC_MAGIC
)
196 if (_IOC_NR(cmd
) > SNAPSHOT_IOC_MAXNR
)
198 if (!capable(CAP_SYS_ADMIN
))
201 if (!mutex_trylock(&pm_mutex
))
204 lock_device_hotplug();
205 data
= filp
->private_data
;
209 case SNAPSHOT_FREEZE
:
213 printk("Syncing filesystems ... ");
217 error
= freeze_processes();
221 error
= create_basic_memory_bitmaps();
229 case SNAPSHOT_UNFREEZE
:
230 if (!data
->frozen
|| data
->ready
)
232 pm_restore_gfp_mask();
233 free_basic_memory_bitmaps();
238 case SNAPSHOT_CREATE_IMAGE
:
239 if (data
->mode
!= O_RDONLY
|| !data
->frozen
|| data
->ready
) {
243 pm_restore_gfp_mask();
244 error
= hibernation_snapshot(data
->platform_support
);
246 error
= put_user(in_suspend
, (int __user
*)arg
);
247 data
->ready
= !freezer_test_done
&& !error
;
248 freezer_test_done
= false;
252 case SNAPSHOT_ATOMIC_RESTORE
:
253 snapshot_write_finalize(&data
->handle
);
254 if (data
->mode
!= O_WRONLY
|| !data
->frozen
||
255 !snapshot_image_loaded(&data
->handle
)) {
259 error
= hibernation_restore(data
->platform_support
);
264 memset(&data
->handle
, 0, sizeof(struct snapshot_handle
));
267 * It is necessary to thaw kernel threads here, because
268 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
269 * SNAPSHOT_FREE. In that case, if kernel threads were not
270 * thawed, the preallocation of memory carried out by
271 * hibernation_snapshot() might run into problems (i.e. it
272 * might fail or even deadlock).
274 thaw_kernel_threads();
277 case SNAPSHOT_PREF_IMAGE_SIZE
:
281 case SNAPSHOT_GET_IMAGE_SIZE
:
286 size
= snapshot_get_image_size();
288 error
= put_user(size
, (loff_t __user
*)arg
);
291 case SNAPSHOT_AVAIL_SWAP_SIZE
:
292 size
= count_swap_pages(data
->swap
, 1);
294 error
= put_user(size
, (loff_t __user
*)arg
);
297 case SNAPSHOT_ALLOC_SWAP_PAGE
:
298 if (data
->swap
< 0 || data
->swap
>= MAX_SWAPFILES
) {
302 offset
= alloc_swapdev_block(data
->swap
);
304 offset
<<= PAGE_SHIFT
;
305 error
= put_user(offset
, (loff_t __user
*)arg
);
311 case SNAPSHOT_FREE_SWAP_PAGES
:
312 if (data
->swap
< 0 || data
->swap
>= MAX_SWAPFILES
) {
316 free_all_swap_pages(data
->swap
);
325 * Tasks are frozen and the notifiers have been called with
326 * PM_HIBERNATION_PREPARE
328 error
= suspend_devices_and_enter(PM_SUSPEND_MEM
);
332 case SNAPSHOT_PLATFORM_SUPPORT
:
333 data
->platform_support
= !!arg
;
336 case SNAPSHOT_POWER_OFF
:
337 if (data
->platform_support
)
338 error
= hibernation_platform_enter();
341 case SNAPSHOT_SET_SWAP_AREA
:
342 if (swsusp_swap_in_use()) {
345 struct resume_swap_area swap_area
;
348 error
= copy_from_user(&swap_area
, (void __user
*)arg
,
349 sizeof(struct resume_swap_area
));
356 * User space encodes device types as two-byte values,
357 * so we need to recode them
359 swdev
= new_decode_dev(swap_area
.dev
);
361 offset
= swap_area
.offset
;
362 data
->swap
= swap_type_of(swdev
, offset
, NULL
);
377 unlock_device_hotplug();
378 mutex_unlock(&pm_mutex
);
385 struct compat_resume_swap_area
{
386 compat_loff_t offset
;
391 snapshot_compat_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
393 BUILD_BUG_ON(sizeof(loff_t
) != sizeof(compat_loff_t
));
396 case SNAPSHOT_GET_IMAGE_SIZE
:
397 case SNAPSHOT_AVAIL_SWAP_SIZE
:
398 case SNAPSHOT_ALLOC_SWAP_PAGE
: {
399 compat_loff_t __user
*uoffset
= compat_ptr(arg
);
406 err
= snapshot_ioctl(file
, cmd
, (unsigned long) &offset
);
408 if (!err
&& put_user(offset
, uoffset
))
413 case SNAPSHOT_CREATE_IMAGE
:
414 return snapshot_ioctl(file
, cmd
,
415 (unsigned long) compat_ptr(arg
));
417 case SNAPSHOT_SET_SWAP_AREA
: {
418 struct compat_resume_swap_area __user
*u_swap_area
=
420 struct resume_swap_area swap_area
;
424 err
= get_user(swap_area
.offset
, &u_swap_area
->offset
);
425 err
|= get_user(swap_area
.dev
, &u_swap_area
->dev
);
430 err
= snapshot_ioctl(file
, SNAPSHOT_SET_SWAP_AREA
,
431 (unsigned long) &swap_area
);
437 return snapshot_ioctl(file
, cmd
, arg
);
441 #endif /* CONFIG_COMPAT */
443 static const struct file_operations snapshot_fops
= {
444 .open
= snapshot_open
,
445 .release
= snapshot_release
,
446 .read
= snapshot_read
,
447 .write
= snapshot_write
,
449 .unlocked_ioctl
= snapshot_ioctl
,
451 .compat_ioctl
= snapshot_compat_ioctl
,
455 static struct miscdevice snapshot_device
= {
456 .minor
= SNAPSHOT_MINOR
,
458 .fops
= &snapshot_fops
,
461 static int __init
snapshot_device_init(void)
463 return misc_register(&snapshot_device
);
466 device_initcall(snapshot_device_init
);