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 bool platform_support
;
45 atomic_t snapshot_device_available
= ATOMIC_INIT(1);
47 static int snapshot_open(struct inode
*inode
, struct file
*filp
)
49 struct snapshot_data
*data
;
54 if (!atomic_add_unless(&snapshot_device_available
, -1, 0)) {
59 if ((filp
->f_flags
& O_ACCMODE
) == O_RDWR
) {
60 atomic_inc(&snapshot_device_available
);
64 nonseekable_open(inode
, filp
);
65 data
= &snapshot_state
;
66 filp
->private_data
= data
;
67 memset(&data
->handle
, 0, sizeof(struct snapshot_handle
));
68 if ((filp
->f_flags
& O_ACCMODE
) == O_RDONLY
) {
69 /* Hibernating. The image device should be accessible. */
70 data
->swap
= swsusp_resume_device
?
71 swap_type_of(swsusp_resume_device
, 0, NULL
) : -1;
72 data
->mode
= O_RDONLY
;
73 error
= pm_notifier_call_chain(PM_HIBERNATION_PREPARE
);
75 pm_notifier_call_chain(PM_POST_HIBERNATION
);
78 * Resuming. We may need to wait for the image device to
81 wait_for_device_probe();
84 data
->mode
= O_WRONLY
;
85 error
= pm_notifier_call_chain(PM_RESTORE_PREPARE
);
87 error
= create_basic_memory_bitmaps();
88 data
->free_bitmaps
= !error
;
91 pm_notifier_call_chain(PM_POST_RESTORE
);
94 atomic_inc(&snapshot_device_available
);
98 data
->platform_support
= false;
101 unlock_system_sleep();
106 static int snapshot_release(struct inode
*inode
, struct file
*filp
)
108 struct snapshot_data
*data
;
113 data
= filp
->private_data
;
114 free_all_swap_pages(data
->swap
);
116 pm_restore_gfp_mask();
117 free_basic_memory_bitmaps();
119 } else if (data
->free_bitmaps
) {
120 free_basic_memory_bitmaps();
122 pm_notifier_call_chain(data
->mode
== O_RDONLY
?
123 PM_POST_HIBERNATION
: PM_POST_RESTORE
);
124 atomic_inc(&snapshot_device_available
);
126 unlock_system_sleep();
131 static ssize_t
snapshot_read(struct file
*filp
, char __user
*buf
,
132 size_t count
, loff_t
*offp
)
134 struct snapshot_data
*data
;
136 loff_t pg_offp
= *offp
& ~PAGE_MASK
;
140 data
= filp
->private_data
;
145 if (!pg_offp
) { /* on page boundary? */
146 res
= snapshot_read_next(&data
->handle
);
150 res
= PAGE_SIZE
- pg_offp
;
153 res
= simple_read_from_buffer(buf
, count
, &pg_offp
,
154 data_of(data
->handle
), res
);
159 unlock_system_sleep();
164 static ssize_t
snapshot_write(struct file
*filp
, const char __user
*buf
,
165 size_t count
, loff_t
*offp
)
167 struct snapshot_data
*data
;
169 loff_t pg_offp
= *offp
& ~PAGE_MASK
;
173 data
= filp
->private_data
;
176 res
= snapshot_write_next(&data
->handle
);
180 res
= PAGE_SIZE
- pg_offp
;
183 res
= simple_write_to_buffer(data_of(data
->handle
), res
, &pg_offp
,
188 unlock_system_sleep();
193 static long snapshot_ioctl(struct file
*filp
, unsigned int cmd
,
197 struct snapshot_data
*data
;
201 if (_IOC_TYPE(cmd
) != SNAPSHOT_IOC_MAGIC
)
203 if (_IOC_NR(cmd
) > SNAPSHOT_IOC_MAXNR
)
205 if (!capable(CAP_SYS_ADMIN
))
208 if (!mutex_trylock(&pm_mutex
))
211 lock_device_hotplug();
212 data
= filp
->private_data
;
216 case SNAPSHOT_FREEZE
:
220 printk("Syncing filesystems ... ");
224 error
= freeze_processes();
228 error
= create_basic_memory_bitmaps();
236 case SNAPSHOT_UNFREEZE
:
237 if (!data
->frozen
|| data
->ready
)
239 pm_restore_gfp_mask();
240 free_basic_memory_bitmaps();
241 data
->free_bitmaps
= false;
243 data
->frozen
= false;
246 case SNAPSHOT_CREATE_IMAGE
:
247 if (data
->mode
!= O_RDONLY
|| !data
->frozen
|| data
->ready
) {
251 pm_restore_gfp_mask();
252 error
= hibernation_snapshot(data
->platform_support
);
254 error
= put_user(in_suspend
, (int __user
*)arg
);
255 data
->ready
= !freezer_test_done
&& !error
;
256 freezer_test_done
= false;
260 case SNAPSHOT_ATOMIC_RESTORE
:
261 snapshot_write_finalize(&data
->handle
);
262 if (data
->mode
!= O_WRONLY
|| !data
->frozen
||
263 !snapshot_image_loaded(&data
->handle
)) {
267 error
= hibernation_restore(data
->platform_support
);
272 memset(&data
->handle
, 0, sizeof(struct snapshot_handle
));
275 * It is necessary to thaw kernel threads here, because
276 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
277 * SNAPSHOT_FREE. In that case, if kernel threads were not
278 * thawed, the preallocation of memory carried out by
279 * hibernation_snapshot() might run into problems (i.e. it
280 * might fail or even deadlock).
282 thaw_kernel_threads();
285 case SNAPSHOT_PREF_IMAGE_SIZE
:
289 case SNAPSHOT_GET_IMAGE_SIZE
:
294 size
= snapshot_get_image_size();
296 error
= put_user(size
, (loff_t __user
*)arg
);
299 case SNAPSHOT_AVAIL_SWAP_SIZE
:
300 size
= count_swap_pages(data
->swap
, 1);
302 error
= put_user(size
, (loff_t __user
*)arg
);
305 case SNAPSHOT_ALLOC_SWAP_PAGE
:
306 if (data
->swap
< 0 || data
->swap
>= MAX_SWAPFILES
) {
310 offset
= alloc_swapdev_block(data
->swap
);
312 offset
<<= PAGE_SHIFT
;
313 error
= put_user(offset
, (loff_t __user
*)arg
);
319 case SNAPSHOT_FREE_SWAP_PAGES
:
320 if (data
->swap
< 0 || data
->swap
>= MAX_SWAPFILES
) {
324 free_all_swap_pages(data
->swap
);
333 * Tasks are frozen and the notifiers have been called with
334 * PM_HIBERNATION_PREPARE
336 error
= suspend_devices_and_enter(PM_SUSPEND_MEM
);
340 case SNAPSHOT_PLATFORM_SUPPORT
:
341 data
->platform_support
= !!arg
;
344 case SNAPSHOT_POWER_OFF
:
345 if (data
->platform_support
)
346 error
= hibernation_platform_enter();
349 case SNAPSHOT_SET_SWAP_AREA
:
350 if (swsusp_swap_in_use()) {
353 struct resume_swap_area swap_area
;
356 error
= copy_from_user(&swap_area
, (void __user
*)arg
,
357 sizeof(struct resume_swap_area
));
364 * User space encodes device types as two-byte values,
365 * so we need to recode them
367 swdev
= new_decode_dev(swap_area
.dev
);
369 offset
= swap_area
.offset
;
370 data
->swap
= swap_type_of(swdev
, offset
, NULL
);
385 unlock_device_hotplug();
386 mutex_unlock(&pm_mutex
);
393 struct compat_resume_swap_area
{
394 compat_loff_t offset
;
399 snapshot_compat_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
401 BUILD_BUG_ON(sizeof(loff_t
) != sizeof(compat_loff_t
));
404 case SNAPSHOT_GET_IMAGE_SIZE
:
405 case SNAPSHOT_AVAIL_SWAP_SIZE
:
406 case SNAPSHOT_ALLOC_SWAP_PAGE
: {
407 compat_loff_t __user
*uoffset
= compat_ptr(arg
);
414 err
= snapshot_ioctl(file
, cmd
, (unsigned long) &offset
);
416 if (!err
&& put_user(offset
, uoffset
))
421 case SNAPSHOT_CREATE_IMAGE
:
422 return snapshot_ioctl(file
, cmd
,
423 (unsigned long) compat_ptr(arg
));
425 case SNAPSHOT_SET_SWAP_AREA
: {
426 struct compat_resume_swap_area __user
*u_swap_area
=
428 struct resume_swap_area swap_area
;
432 err
= get_user(swap_area
.offset
, &u_swap_area
->offset
);
433 err
|= get_user(swap_area
.dev
, &u_swap_area
->dev
);
438 err
= snapshot_ioctl(file
, SNAPSHOT_SET_SWAP_AREA
,
439 (unsigned long) &swap_area
);
445 return snapshot_ioctl(file
, cmd
, arg
);
449 #endif /* CONFIG_COMPAT */
451 static const struct file_operations snapshot_fops
= {
452 .open
= snapshot_open
,
453 .release
= snapshot_release
,
454 .read
= snapshot_read
,
455 .write
= snapshot_write
,
457 .unlocked_ioctl
= snapshot_ioctl
,
459 .compat_ioctl
= snapshot_compat_ioctl
,
463 static struct miscdevice snapshot_device
= {
464 .minor
= SNAPSHOT_MINOR
,
466 .fops
= &snapshot_fops
,
469 static int __init
snapshot_device_init(void)
471 return misc_register(&snapshot_device
);
474 device_initcall(snapshot_device_init
);