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 <linux/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
;
50 int error
, nr_calls
= 0;
52 if (!hibernation_available())
55 if (kernel_is_locked_down())
60 if (!atomic_add_unless(&snapshot_device_available
, -1, 0)) {
65 if ((filp
->f_flags
& O_ACCMODE
) == O_RDWR
) {
66 atomic_inc(&snapshot_device_available
);
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
) {
75 /* Hibernating. The image device should be accessible. */
76 data
->swap
= swsusp_resume_device
?
77 swap_type_of(swsusp_resume_device
, 0, NULL
) : -1;
78 data
->mode
= O_RDONLY
;
79 data
->free_bitmaps
= false;
80 error
= __pm_notifier_call_chain(PM_HIBERNATION_PREPARE
, -1, &nr_calls
);
82 __pm_notifier_call_chain(PM_POST_HIBERNATION
, --nr_calls
, NULL
);
85 * Resuming. We may need to wait for the image device to
88 wait_for_device_probe();
91 data
->mode
= O_WRONLY
;
92 error
= __pm_notifier_call_chain(PM_RESTORE_PREPARE
, -1, &nr_calls
);
94 error
= create_basic_memory_bitmaps();
95 data
->free_bitmaps
= !error
;
100 __pm_notifier_call_chain(PM_POST_RESTORE
, nr_calls
, NULL
);
103 atomic_inc(&snapshot_device_available
);
105 data
->frozen
= false;
107 data
->platform_support
= false;
110 unlock_system_sleep();
115 static int snapshot_release(struct inode
*inode
, struct file
*filp
)
117 struct snapshot_data
*data
;
122 data
= filp
->private_data
;
123 free_all_swap_pages(data
->swap
);
125 pm_restore_gfp_mask();
126 free_basic_memory_bitmaps();
128 } else if (data
->free_bitmaps
) {
129 free_basic_memory_bitmaps();
131 pm_notifier_call_chain(data
->mode
== O_RDONLY
?
132 PM_POST_HIBERNATION
: PM_POST_RESTORE
);
133 atomic_inc(&snapshot_device_available
);
135 unlock_system_sleep();
140 static ssize_t
snapshot_read(struct file
*filp
, char __user
*buf
,
141 size_t count
, loff_t
*offp
)
143 struct snapshot_data
*data
;
145 loff_t pg_offp
= *offp
& ~PAGE_MASK
;
149 data
= filp
->private_data
;
154 if (!pg_offp
) { /* on page boundary? */
155 res
= snapshot_read_next(&data
->handle
);
159 res
= PAGE_SIZE
- pg_offp
;
162 res
= simple_read_from_buffer(buf
, count
, &pg_offp
,
163 data_of(data
->handle
), res
);
168 unlock_system_sleep();
173 static ssize_t
snapshot_write(struct file
*filp
, const char __user
*buf
,
174 size_t count
, loff_t
*offp
)
176 struct snapshot_data
*data
;
178 loff_t pg_offp
= *offp
& ~PAGE_MASK
;
182 data
= filp
->private_data
;
185 res
= snapshot_write_next(&data
->handle
);
189 res
= PAGE_SIZE
- pg_offp
;
192 res
= simple_write_to_buffer(data_of(data
->handle
), res
, &pg_offp
,
197 unlock_system_sleep();
202 static long snapshot_ioctl(struct file
*filp
, unsigned int cmd
,
206 struct snapshot_data
*data
;
210 if (_IOC_TYPE(cmd
) != SNAPSHOT_IOC_MAGIC
)
212 if (_IOC_NR(cmd
) > SNAPSHOT_IOC_MAXNR
)
214 if (!capable(CAP_SYS_ADMIN
))
217 if (!mutex_trylock(&pm_mutex
))
220 lock_device_hotplug();
221 data
= filp
->private_data
;
225 case SNAPSHOT_FREEZE
:
229 printk("Syncing filesystems ... ");
233 error
= freeze_processes();
237 error
= create_basic_memory_bitmaps();
245 case SNAPSHOT_UNFREEZE
:
246 if (!data
->frozen
|| data
->ready
)
248 pm_restore_gfp_mask();
249 free_basic_memory_bitmaps();
250 data
->free_bitmaps
= false;
252 data
->frozen
= false;
255 case SNAPSHOT_CREATE_IMAGE
:
256 if (data
->mode
!= O_RDONLY
|| !data
->frozen
|| data
->ready
) {
260 pm_restore_gfp_mask();
261 error
= hibernation_snapshot(data
->platform_support
);
263 error
= put_user(in_suspend
, (int __user
*)arg
);
264 data
->ready
= !freezer_test_done
&& !error
;
265 freezer_test_done
= false;
269 case SNAPSHOT_ATOMIC_RESTORE
:
270 snapshot_write_finalize(&data
->handle
);
271 if (data
->mode
!= O_WRONLY
|| !data
->frozen
||
272 !snapshot_image_loaded(&data
->handle
)) {
276 error
= hibernation_restore(data
->platform_support
);
281 memset(&data
->handle
, 0, sizeof(struct snapshot_handle
));
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).
291 thaw_kernel_threads();
294 case SNAPSHOT_PREF_IMAGE_SIZE
:
298 case SNAPSHOT_GET_IMAGE_SIZE
:
303 size
= snapshot_get_image_size();
305 error
= put_user(size
, (loff_t __user
*)arg
);
308 case SNAPSHOT_AVAIL_SWAP_SIZE
:
309 size
= count_swap_pages(data
->swap
, 1);
311 error
= put_user(size
, (loff_t __user
*)arg
);
314 case SNAPSHOT_ALLOC_SWAP_PAGE
:
315 if (data
->swap
< 0 || data
->swap
>= MAX_SWAPFILES
) {
319 offset
= alloc_swapdev_block(data
->swap
);
321 offset
<<= PAGE_SHIFT
;
322 error
= put_user(offset
, (loff_t __user
*)arg
);
328 case SNAPSHOT_FREE_SWAP_PAGES
:
329 if (data
->swap
< 0 || data
->swap
>= MAX_SWAPFILES
) {
333 free_all_swap_pages(data
->swap
);
342 * Tasks are frozen and the notifiers have been called with
343 * PM_HIBERNATION_PREPARE
345 error
= suspend_devices_and_enter(PM_SUSPEND_MEM
);
349 case SNAPSHOT_PLATFORM_SUPPORT
:
350 data
->platform_support
= !!arg
;
353 case SNAPSHOT_POWER_OFF
:
354 if (data
->platform_support
)
355 error
= hibernation_platform_enter();
358 case SNAPSHOT_SET_SWAP_AREA
:
359 if (swsusp_swap_in_use()) {
362 struct resume_swap_area swap_area
;
365 error
= copy_from_user(&swap_area
, (void __user
*)arg
,
366 sizeof(struct resume_swap_area
));
373 * User space encodes device types as two-byte values,
374 * so we need to recode them
376 swdev
= new_decode_dev(swap_area
.dev
);
378 offset
= swap_area
.offset
;
379 data
->swap
= swap_type_of(swdev
, offset
, NULL
);
394 unlock_device_hotplug();
395 mutex_unlock(&pm_mutex
);
402 struct compat_resume_swap_area
{
403 compat_loff_t offset
;
408 snapshot_compat_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
410 BUILD_BUG_ON(sizeof(loff_t
) != sizeof(compat_loff_t
));
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
);
423 err
= snapshot_ioctl(file
, cmd
, (unsigned long) &offset
);
425 if (!err
&& put_user(offset
, uoffset
))
430 case SNAPSHOT_CREATE_IMAGE
:
431 return snapshot_ioctl(file
, cmd
,
432 (unsigned long) compat_ptr(arg
));
434 case SNAPSHOT_SET_SWAP_AREA
: {
435 struct compat_resume_swap_area __user
*u_swap_area
=
437 struct resume_swap_area swap_area
;
441 err
= get_user(swap_area
.offset
, &u_swap_area
->offset
);
442 err
|= get_user(swap_area
.dev
, &u_swap_area
->dev
);
447 err
= snapshot_ioctl(file
, SNAPSHOT_SET_SWAP_AREA
,
448 (unsigned long) &swap_area
);
454 return snapshot_ioctl(file
, cmd
, arg
);
458 #endif /* CONFIG_COMPAT */
460 static const struct file_operations snapshot_fops
= {
461 .open
= snapshot_open
,
462 .release
= snapshot_release
,
463 .read
= snapshot_read
,
464 .write
= snapshot_write
,
466 .unlocked_ioctl
= snapshot_ioctl
,
468 .compat_ioctl
= snapshot_compat_ioctl
,
472 static struct miscdevice snapshot_device
= {
473 .minor
= SNAPSHOT_MINOR
,
475 .fops
= &snapshot_fops
,
478 static int __init
snapshot_device_init(void)
480 return misc_register(&snapshot_device
);
483 device_initcall(snapshot_device_init
);