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/console.h>
24 #include <linux/cpu.h>
25 #include <linux/freezer.h>
27 #include <asm/uaccess.h>
31 #define SNAPSHOT_MINOR 231
33 static struct snapshot_data {
34 struct snapshot_handle handle;
39 char platform_suspend;
42 atomic_t snapshot_device_available = ATOMIC_INIT(1);
44 static int snapshot_open(struct inode *inode, struct file *filp)
46 struct snapshot_data *data;
48 if (!atomic_add_unless(&snapshot_device_available, -1, 0))
51 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
52 atomic_inc(&snapshot_device_available);
55 if(create_basic_memory_bitmaps()) {
56 atomic_inc(&snapshot_device_available);
59 nonseekable_open(inode, filp);
60 data = &snapshot_state;
61 filp->private_data = data;
62 memset(&data->handle, 0, sizeof(struct snapshot_handle));
63 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
64 data->swap = swsusp_resume_device ?
65 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
66 data->mode = O_RDONLY;
69 data->mode = O_WRONLY;
73 data->platform_suspend = 0;
78 static int snapshot_release(struct inode *inode, struct file *filp)
80 struct snapshot_data *data;
83 free_basic_memory_bitmaps();
84 data = filp->private_data;
85 free_all_swap_pages(data->swap);
87 mutex_lock(&pm_mutex);
89 enable_nonboot_cpus();
90 mutex_unlock(&pm_mutex);
92 atomic_inc(&snapshot_device_available);
96 static ssize_t snapshot_read(struct file *filp, char __user *buf,
97 size_t count, loff_t *offp)
99 struct snapshot_data *data;
102 data = filp->private_data;
103 res = snapshot_read_next(&data->handle, count);
105 if (copy_to_user(buf, data_of(data->handle), res))
108 *offp = data->handle.offset;
113 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
114 size_t count, loff_t *offp)
116 struct snapshot_data *data;
119 data = filp->private_data;
120 res = snapshot_write_next(&data->handle, count);
122 if (copy_from_user(data_of(data->handle), buf, res))
125 *offp = data->handle.offset;
130 static inline int platform_prepare(void)
134 if (pm_ops && pm_ops->prepare)
135 error = pm_ops->prepare(PM_SUSPEND_DISK);
140 static inline void platform_finish(void)
142 if (pm_ops && pm_ops->finish)
143 pm_ops->finish(PM_SUSPEND_DISK);
146 static inline int snapshot_suspend(int platform_suspend)
150 mutex_lock(&pm_mutex);
151 /* Free memory before shutting down devices. */
152 error = swsusp_shrink_memory();
156 if (platform_suspend) {
157 error = platform_prepare();
162 error = device_suspend(PMSG_FREEZE);
166 error = disable_nonboot_cpus();
169 error = swsusp_suspend();
171 enable_nonboot_cpus();
173 if (platform_suspend)
179 mutex_unlock(&pm_mutex);
183 static inline int snapshot_restore(int platform_suspend)
187 mutex_lock(&pm_mutex);
188 pm_prepare_console();
189 if (platform_suspend) {
190 error = platform_prepare();
195 error = device_suspend(PMSG_PRETHAW);
199 error = disable_nonboot_cpus();
201 error = swsusp_resume();
203 enable_nonboot_cpus();
205 if (platform_suspend)
211 pm_restore_console();
212 mutex_unlock(&pm_mutex);
216 static int snapshot_ioctl(struct inode *inode, struct file *filp,
217 unsigned int cmd, unsigned long arg)
220 struct snapshot_data *data;
224 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
226 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
228 if (!capable(CAP_SYS_ADMIN))
231 data = filp->private_data;
235 case SNAPSHOT_FREEZE:
238 mutex_lock(&pm_mutex);
239 if (freeze_processes()) {
243 mutex_unlock(&pm_mutex);
248 case SNAPSHOT_UNFREEZE:
251 mutex_lock(&pm_mutex);
253 mutex_unlock(&pm_mutex);
257 case SNAPSHOT_ATOMIC_SNAPSHOT:
258 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
262 error = snapshot_suspend(data->platform_suspend);
264 error = put_user(in_suspend, (unsigned int __user *)arg);
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 = snapshot_restore(data->platform_suspend);
281 memset(&data->handle, 0, sizeof(struct snapshot_handle));
285 case SNAPSHOT_SET_IMAGE_SIZE:
289 case SNAPSHOT_AVAIL_SWAP:
290 avail = count_swap_pages(data->swap, 1);
291 avail <<= PAGE_SHIFT;
292 error = put_user(avail, (loff_t __user *)arg);
295 case SNAPSHOT_GET_SWAP_PAGE:
296 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
300 offset = alloc_swapdev_block(data->swap);
302 offset <<= PAGE_SHIFT;
303 error = put_user(offset, (sector_t __user *)arg);
309 case SNAPSHOT_FREE_SWAP_PAGES:
310 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
314 free_all_swap_pages(data->swap);
317 case SNAPSHOT_SET_SWAP_FILE:
318 if (!swsusp_swap_in_use()) {
320 * User space encodes device types as two-byte values,
321 * so we need to recode them
323 if (old_decode_dev(arg)) {
324 data->swap = swap_type_of(old_decode_dev(arg),
348 if (!mutex_trylock(&pm_mutex)) {
353 if (pm_ops->prepare) {
354 error = pm_ops->prepare(PM_SUSPEND_MEM);
359 /* Put devices to sleep */
361 error = device_suspend(PMSG_SUSPEND);
363 printk(KERN_ERR "Failed to suspend some devices.\n");
365 error = disable_nonboot_cpus();
367 /* Enter S3, system is already frozen */
368 suspend_enter(PM_SUSPEND_MEM);
369 enable_nonboot_cpus();
371 /* Wake up devices */
376 pm_ops->finish(PM_SUSPEND_MEM);
379 mutex_unlock(&pm_mutex);
388 if (pm_ops && pm_ops->enter) {
389 data->platform_suspend = 1;
397 if (data->platform_suspend) {
398 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
399 error = pm_ops->enter(PM_SUSPEND_DISK);
405 if (data->platform_suspend)
411 printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
416 case SNAPSHOT_SET_SWAP_AREA:
417 if (swsusp_swap_in_use()) {
420 struct resume_swap_area swap_area;
423 error = copy_from_user(&swap_area, (void __user *)arg,
424 sizeof(struct resume_swap_area));
431 * User space encodes device types as two-byte values,
432 * so we need to recode them
434 swdev = old_decode_dev(swap_area.dev);
436 offset = swap_area.offset;
437 data->swap = swap_type_of(swdev, offset, NULL);
455 static const struct file_operations snapshot_fops = {
456 .open = snapshot_open,
457 .release = snapshot_release,
458 .read = snapshot_read,
459 .write = snapshot_write,
461 .ioctl = snapshot_ioctl,
464 static struct miscdevice snapshot_device = {
465 .minor = SNAPSHOT_MINOR,
467 .fops = &snapshot_fops,
470 static int __init snapshot_device_init(void)
472 return misc_register(&snapshot_device);
475 device_initcall(snapshot_device_init);