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/kmod.h>
16 #include <linux/string.h>
17 #include <linux/device.h>
18 #include <linux/miscdevice.h>
20 #include <linux/swap.h>
21 #include <linux/swapops.h>
24 #include <linux/compat.h>
25 #include <linux/console.h>
26 #include <linux/cpu.h>
27 #include <linux/freezer.h>
28 #include <scsi/scsi_scan.h>
30 #include <asm/uaccess.h>
35 #define SNAPSHOT_MINOR 231
37 static struct snapshot_data {
38 struct snapshot_handle handle;
43 char platform_support;
46 atomic_t snapshot_device_available = ATOMIC_INIT(1);
48 static int snapshot_open(struct inode *inode, struct file *filp)
50 struct snapshot_data *data;
55 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
60 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
61 atomic_inc(&snapshot_device_available);
65 if(create_basic_memory_bitmaps()) {
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 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
81 pm_notifier_call_chain(PM_POST_HIBERNATION);
84 * Resuming. We may need to wait for the image device to
87 wait_for_device_probe();
88 scsi_complete_async_scans();
91 data->mode = O_WRONLY;
92 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
94 pm_notifier_call_chain(PM_POST_RESTORE);
97 free_basic_memory_bitmaps();
98 atomic_inc(&snapshot_device_available);
102 data->platform_support = 0;
105 unlock_system_sleep();
110 static int snapshot_release(struct inode *inode, struct file *filp)
112 struct snapshot_data *data;
117 free_basic_memory_bitmaps();
118 data = filp->private_data;
119 free_all_swap_pages(data->swap);
121 pm_restore_gfp_mask();
124 pm_notifier_call_chain(data->mode == O_RDONLY ?
125 PM_POST_HIBERNATION : PM_POST_RESTORE);
126 atomic_inc(&snapshot_device_available);
128 unlock_system_sleep();
133 static ssize_t snapshot_read(struct file *filp, char __user *buf,
134 size_t count, loff_t *offp)
136 struct snapshot_data *data;
138 loff_t pg_offp = *offp & ~PAGE_MASK;
142 data = filp->private_data;
147 if (!pg_offp) { /* on page boundary? */
148 res = snapshot_read_next(&data->handle);
152 res = PAGE_SIZE - pg_offp;
155 res = simple_read_from_buffer(buf, count, &pg_offp,
156 data_of(data->handle), res);
161 unlock_system_sleep();
166 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
167 size_t count, loff_t *offp)
169 struct snapshot_data *data;
171 loff_t pg_offp = *offp & ~PAGE_MASK;
175 data = filp->private_data;
178 res = snapshot_write_next(&data->handle);
182 res = PAGE_SIZE - pg_offp;
185 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
190 unlock_system_sleep();
195 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
199 struct snapshot_data *data;
203 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
205 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
207 if (!capable(CAP_SYS_ADMIN))
210 if (!mutex_trylock(&pm_mutex))
213 data = filp->private_data;
217 case SNAPSHOT_FREEZE:
221 printk("Syncing filesystems ... ");
225 error = usermodehelper_disable();
229 error = freeze_processes();
231 usermodehelper_enable();
236 case SNAPSHOT_UNFREEZE:
237 if (!data->frozen || data->ready)
239 pm_restore_gfp_mask();
241 usermodehelper_enable();
245 case SNAPSHOT_CREATE_IMAGE:
246 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
250 pm_restore_gfp_mask();
251 error = hibernation_snapshot(data->platform_support);
253 error = put_user(in_suspend, (int __user *)arg);
254 if (!error && !freezer_test_done)
256 if (freezer_test_done) {
257 freezer_test_done = false;
263 case SNAPSHOT_ATOMIC_RESTORE:
264 snapshot_write_finalize(&data->handle);
265 if (data->mode != O_WRONLY || !data->frozen ||
266 !snapshot_image_loaded(&data->handle)) {
270 error = hibernation_restore(data->platform_support);
275 memset(&data->handle, 0, sizeof(struct snapshot_handle));
278 * It is necessary to thaw kernel threads here, because
279 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
280 * SNAPSHOT_FREE. In that case, if kernel threads were not
281 * thawed, the preallocation of memory carried out by
282 * hibernation_snapshot() might run into problems (i.e. it
283 * might fail or even deadlock).
285 thaw_kernel_threads();
288 case SNAPSHOT_PREF_IMAGE_SIZE:
292 case SNAPSHOT_GET_IMAGE_SIZE:
297 size = snapshot_get_image_size();
299 error = put_user(size, (loff_t __user *)arg);
302 case SNAPSHOT_AVAIL_SWAP_SIZE:
303 size = count_swap_pages(data->swap, 1);
305 error = put_user(size, (loff_t __user *)arg);
308 case SNAPSHOT_ALLOC_SWAP_PAGE:
309 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
313 offset = alloc_swapdev_block(data->swap);
315 offset <<= PAGE_SHIFT;
316 error = put_user(offset, (loff_t __user *)arg);
322 case SNAPSHOT_FREE_SWAP_PAGES:
323 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
327 free_all_swap_pages(data->swap);
336 * Tasks are frozen and the notifiers have been called with
337 * PM_HIBERNATION_PREPARE
339 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
343 case SNAPSHOT_PLATFORM_SUPPORT:
344 data->platform_support = !!arg;
347 case SNAPSHOT_POWER_OFF:
348 if (data->platform_support)
349 error = hibernation_platform_enter();
352 case SNAPSHOT_SET_SWAP_AREA:
353 if (swsusp_swap_in_use()) {
356 struct resume_swap_area swap_area;
359 error = copy_from_user(&swap_area, (void __user *)arg,
360 sizeof(struct resume_swap_area));
367 * User space encodes device types as two-byte values,
368 * so we need to recode them
370 swdev = new_decode_dev(swap_area.dev);
372 offset = swap_area.offset;
373 data->swap = swap_type_of(swdev, offset, NULL);
388 mutex_unlock(&pm_mutex);
395 struct compat_resume_swap_area {
396 compat_loff_t offset;
401 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
403 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
406 case SNAPSHOT_GET_IMAGE_SIZE:
407 case SNAPSHOT_AVAIL_SWAP_SIZE:
408 case SNAPSHOT_ALLOC_SWAP_PAGE: {
409 compat_loff_t __user *uoffset = compat_ptr(arg);
416 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
418 if (!err && put_user(offset, uoffset))
423 case SNAPSHOT_CREATE_IMAGE:
424 return snapshot_ioctl(file, cmd,
425 (unsigned long) compat_ptr(arg));
427 case SNAPSHOT_SET_SWAP_AREA: {
428 struct compat_resume_swap_area __user *u_swap_area =
430 struct resume_swap_area swap_area;
434 err = get_user(swap_area.offset, &u_swap_area->offset);
435 err |= get_user(swap_area.dev, &u_swap_area->dev);
440 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
441 (unsigned long) &swap_area);
447 return snapshot_ioctl(file, cmd, arg);
451 #endif /* CONFIG_COMPAT */
453 static const struct file_operations snapshot_fops = {
454 .open = snapshot_open,
455 .release = snapshot_release,
456 .read = snapshot_read,
457 .write = snapshot_write,
459 .unlocked_ioctl = snapshot_ioctl,
461 .compat_ioctl = snapshot_compat_ioctl,
465 static struct miscdevice snapshot_device = {
466 .minor = SNAPSHOT_MINOR,
468 .fops = &snapshot_fops,
471 static int __init snapshot_device_init(void)
473 return misc_register(&snapshot_device);
476 device_initcall(snapshot_device_init);