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;
52 if (!hibernation_available())
57 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
62 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
63 atomic_inc(&snapshot_device_available);
67 nonseekable_open(inode, filp);
68 data = &snapshot_state;
69 filp->private_data = data;
70 memset(&data->handle, 0, sizeof(struct snapshot_handle));
71 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
72 /* Hibernating. The image device should be accessible. */
73 data->swap = swsusp_resume_device ?
74 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
75 data->mode = O_RDONLY;
76 data->free_bitmaps = false;
77 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
79 pm_notifier_call_chain(PM_POST_HIBERNATION);
82 * Resuming. We may need to wait for the image device to
85 wait_for_device_probe();
88 data->mode = O_WRONLY;
89 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
91 error = create_basic_memory_bitmaps();
92 data->free_bitmaps = !error;
95 pm_notifier_call_chain(PM_POST_RESTORE);
98 atomic_inc(&snapshot_device_available);
100 data->frozen = false;
102 data->platform_support = false;
105 unlock_system_sleep();
110 static int snapshot_release(struct inode *inode, struct file *filp)
112 struct snapshot_data *data;
117 data = filp->private_data;
118 free_all_swap_pages(data->swap);
120 pm_restore_gfp_mask();
121 free_basic_memory_bitmaps();
123 } else if (data->free_bitmaps) {
124 free_basic_memory_bitmaps();
126 pm_notifier_call_chain(data->mode == O_RDONLY ?
127 PM_POST_HIBERNATION : PM_POST_RESTORE);
128 atomic_inc(&snapshot_device_available);
130 unlock_system_sleep();
135 static ssize_t snapshot_read(struct file *filp, char __user *buf,
136 size_t count, loff_t *offp)
138 struct snapshot_data *data;
140 loff_t pg_offp = *offp & ~PAGE_MASK;
144 data = filp->private_data;
149 if (!pg_offp) { /* on page boundary? */
150 res = snapshot_read_next(&data->handle);
154 res = PAGE_SIZE - pg_offp;
157 res = simple_read_from_buffer(buf, count, &pg_offp,
158 data_of(data->handle), res);
163 unlock_system_sleep();
168 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
169 size_t count, loff_t *offp)
171 struct snapshot_data *data;
173 loff_t pg_offp = *offp & ~PAGE_MASK;
177 data = filp->private_data;
180 res = snapshot_write_next(&data->handle);
184 res = PAGE_SIZE - pg_offp;
187 if (!data_of(data->handle)) {
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);