1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/power/user.c
5 * This file provides the user space interface for software suspend/resume.
7 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
10 #include <linux/suspend.h>
11 #include <linux/reboot.h>
12 #include <linux/string.h>
13 #include <linux/device.h>
14 #include <linux/miscdevice.h>
16 #include <linux/swap.h>
17 #include <linux/swapops.h>
20 #include <linux/compat.h>
21 #include <linux/console.h>
22 #include <linux/cpu.h>
23 #include <linux/freezer.h>
25 #include <linux/uaccess.h>
30 static struct snapshot_data {
31 struct snapshot_handle handle;
36 bool platform_support;
38 struct inode *bd_inode;
41 int is_hibernate_resume_dev(const struct inode *bd_inode)
43 return hibernation_available() && snapshot_state.bd_inode == bd_inode;
46 static int snapshot_open(struct inode *inode, struct file *filp)
48 struct snapshot_data *data;
51 if (!hibernation_available())
56 if (!hibernate_acquire()) {
61 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
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) {
71 /* Hibernating. The image device should be accessible. */
72 data->swap = swsusp_resume_device ?
73 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
74 data->mode = O_RDONLY;
75 data->free_bitmaps = false;
76 error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
79 * Resuming. We may need to wait for the image device to
82 wait_for_device_probe();
85 data->mode = O_WRONLY;
86 error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
88 error = create_basic_memory_bitmaps();
89 data->free_bitmaps = !error;
97 data->platform_support = false;
98 data->bd_inode = NULL;
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 data->bd_inode = NULL;
115 free_all_swap_pages(data->swap);
117 pm_restore_gfp_mask();
118 free_basic_memory_bitmaps();
120 } else if (data->free_bitmaps) {
121 free_basic_memory_bitmaps();
123 pm_notifier_call_chain(data->mode == O_RDONLY ?
124 PM_POST_HIBERNATION : PM_POST_RESTORE);
127 unlock_system_sleep();
132 static ssize_t snapshot_read(struct file *filp, char __user *buf,
133 size_t count, loff_t *offp)
135 struct snapshot_data *data;
137 loff_t pg_offp = *offp & ~PAGE_MASK;
141 data = filp->private_data;
146 if (!pg_offp) { /* on page boundary? */
147 res = snapshot_read_next(&data->handle);
151 res = PAGE_SIZE - pg_offp;
154 res = simple_read_from_buffer(buf, count, &pg_offp,
155 data_of(data->handle), res);
160 unlock_system_sleep();
165 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
166 size_t count, loff_t *offp)
168 struct snapshot_data *data;
170 loff_t pg_offp = *offp & ~PAGE_MASK;
174 data = filp->private_data;
177 res = snapshot_write_next(&data->handle);
181 res = PAGE_SIZE - pg_offp;
184 if (!data_of(data->handle)) {
189 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
194 unlock_system_sleep();
199 struct compat_resume_swap_area {
200 compat_loff_t offset;
204 static int snapshot_set_swap_area(struct snapshot_data *data,
207 struct block_device *bdev;
211 if (swsusp_swap_in_use())
214 if (in_compat_syscall()) {
215 struct compat_resume_swap_area swap_area;
217 if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
219 swdev = new_decode_dev(swap_area.dev);
220 offset = swap_area.offset;
222 struct resume_swap_area swap_area;
224 if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
226 swdev = new_decode_dev(swap_area.dev);
227 offset = swap_area.offset;
231 * User space encodes device types as two-byte values,
232 * so we need to recode them
238 data->swap = swap_type_of(swdev, offset, &bdev);
242 data->bd_inode = bdev->bd_inode;
247 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
251 struct snapshot_data *data;
255 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
257 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
259 if (!capable(CAP_SYS_ADMIN))
262 if (!mutex_trylock(&system_transition_mutex))
265 lock_device_hotplug();
266 data = filp->private_data;
270 case SNAPSHOT_FREEZE:
276 error = freeze_processes();
280 error = create_basic_memory_bitmaps();
288 case SNAPSHOT_UNFREEZE:
289 if (!data->frozen || data->ready)
291 pm_restore_gfp_mask();
292 free_basic_memory_bitmaps();
293 data->free_bitmaps = false;
295 data->frozen = false;
298 case SNAPSHOT_CREATE_IMAGE:
299 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
303 pm_restore_gfp_mask();
304 error = hibernation_snapshot(data->platform_support);
306 error = put_user(in_suspend, (int __user *)arg);
307 data->ready = !freezer_test_done && !error;
308 freezer_test_done = false;
312 case SNAPSHOT_ATOMIC_RESTORE:
313 snapshot_write_finalize(&data->handle);
314 if (data->mode != O_WRONLY || !data->frozen ||
315 !snapshot_image_loaded(&data->handle)) {
319 error = hibernation_restore(data->platform_support);
324 memset(&data->handle, 0, sizeof(struct snapshot_handle));
327 * It is necessary to thaw kernel threads here, because
328 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
329 * SNAPSHOT_FREE. In that case, if kernel threads were not
330 * thawed, the preallocation of memory carried out by
331 * hibernation_snapshot() might run into problems (i.e. it
332 * might fail or even deadlock).
334 thaw_kernel_threads();
337 case SNAPSHOT_PREF_IMAGE_SIZE:
341 case SNAPSHOT_GET_IMAGE_SIZE:
346 size = snapshot_get_image_size();
348 error = put_user(size, (loff_t __user *)arg);
351 case SNAPSHOT_AVAIL_SWAP_SIZE:
352 size = count_swap_pages(data->swap, 1);
354 error = put_user(size, (loff_t __user *)arg);
357 case SNAPSHOT_ALLOC_SWAP_PAGE:
358 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
362 offset = alloc_swapdev_block(data->swap);
364 offset <<= PAGE_SHIFT;
365 error = put_user(offset, (loff_t __user *)arg);
371 case SNAPSHOT_FREE_SWAP_PAGES:
372 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
376 free_all_swap_pages(data->swap);
385 * Tasks are frozen and the notifiers have been called with
386 * PM_HIBERNATION_PREPARE
388 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
392 case SNAPSHOT_PLATFORM_SUPPORT:
393 data->platform_support = !!arg;
396 case SNAPSHOT_POWER_OFF:
397 if (data->platform_support)
398 error = hibernation_platform_enter();
401 case SNAPSHOT_SET_SWAP_AREA:
402 error = snapshot_set_swap_area(data, (void __user *)arg);
410 unlock_device_hotplug();
411 mutex_unlock(&system_transition_mutex);
418 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
420 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
423 case SNAPSHOT_GET_IMAGE_SIZE:
424 case SNAPSHOT_AVAIL_SWAP_SIZE:
425 case SNAPSHOT_ALLOC_SWAP_PAGE:
426 case SNAPSHOT_CREATE_IMAGE:
427 case SNAPSHOT_SET_SWAP_AREA:
428 return snapshot_ioctl(file, cmd,
429 (unsigned long) compat_ptr(arg));
431 return snapshot_ioctl(file, cmd, arg);
434 #endif /* CONFIG_COMPAT */
436 static const struct file_operations snapshot_fops = {
437 .open = snapshot_open,
438 .release = snapshot_release,
439 .read = snapshot_read,
440 .write = snapshot_write,
442 .unlocked_ioctl = snapshot_ioctl,
444 .compat_ioctl = snapshot_compat_ioctl,
448 static struct miscdevice snapshot_device = {
449 .minor = SNAPSHOT_MINOR,
451 .fops = &snapshot_fops,
454 static int __init snapshot_device_init(void)
456 return misc_register(&snapshot_device);
459 device_initcall(snapshot_device_init);