Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / kernel / power / user.c
blob22df9f7ff672425f1200c421eceff5a41c220ff2
1 /*
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>
18 #include <linux/mm.h>
19 #include <linux/swap.h>
20 #include <linux/swapops.h>
21 #include <linux/pm.h>
22 #include <linux/fs.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>
30 #include "power.h"
33 #define SNAPSHOT_MINOR 231
35 static struct snapshot_data {
36 struct snapshot_handle handle;
37 int swap;
38 int mode;
39 bool frozen;
40 bool ready;
41 bool platform_support;
42 bool free_bitmaps;
43 } snapshot_state;
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())
53 return -EPERM;
55 lock_system_sleep();
57 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
58 error = -EBUSY;
59 goto Unlock;
62 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
63 atomic_inc(&snapshot_device_available);
64 error = -ENOSYS;
65 goto Unlock;
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, -1, &nr_calls);
78 if (error)
79 __pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL);
80 } else {
82 * Resuming. We may need to wait for the image device to
83 * appear.
85 wait_for_device_probe();
87 data->swap = -1;
88 data->mode = O_WRONLY;
89 error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
90 if (!error) {
91 error = create_basic_memory_bitmaps();
92 data->free_bitmaps = !error;
93 } else
94 nr_calls--;
96 if (error)
97 __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
99 if (error)
100 atomic_inc(&snapshot_device_available);
102 data->frozen = false;
103 data->ready = false;
104 data->platform_support = false;
106 Unlock:
107 unlock_system_sleep();
109 return error;
112 static int snapshot_release(struct inode *inode, struct file *filp)
114 struct snapshot_data *data;
116 lock_system_sleep();
118 swsusp_free();
119 data = filp->private_data;
120 free_all_swap_pages(data->swap);
121 if (data->frozen) {
122 pm_restore_gfp_mask();
123 free_basic_memory_bitmaps();
124 thaw_processes();
125 } else if (data->free_bitmaps) {
126 free_basic_memory_bitmaps();
128 pm_notifier_call_chain(data->mode == O_RDONLY ?
129 PM_POST_HIBERNATION : PM_POST_RESTORE);
130 atomic_inc(&snapshot_device_available);
132 unlock_system_sleep();
134 return 0;
137 static ssize_t snapshot_read(struct file *filp, char __user *buf,
138 size_t count, loff_t *offp)
140 struct snapshot_data *data;
141 ssize_t res;
142 loff_t pg_offp = *offp & ~PAGE_MASK;
144 lock_system_sleep();
146 data = filp->private_data;
147 if (!data->ready) {
148 res = -ENODATA;
149 goto Unlock;
151 if (!pg_offp) { /* on page boundary? */
152 res = snapshot_read_next(&data->handle);
153 if (res <= 0)
154 goto Unlock;
155 } else {
156 res = PAGE_SIZE - pg_offp;
159 res = simple_read_from_buffer(buf, count, &pg_offp,
160 data_of(data->handle), res);
161 if (res > 0)
162 *offp += res;
164 Unlock:
165 unlock_system_sleep();
167 return res;
170 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
171 size_t count, loff_t *offp)
173 struct snapshot_data *data;
174 ssize_t res;
175 loff_t pg_offp = *offp & ~PAGE_MASK;
177 lock_system_sleep();
179 data = filp->private_data;
181 if (!pg_offp) {
182 res = snapshot_write_next(&data->handle);
183 if (res <= 0)
184 goto unlock;
185 } else {
186 res = PAGE_SIZE - pg_offp;
189 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
190 buf, count);
191 if (res > 0)
192 *offp += res;
193 unlock:
194 unlock_system_sleep();
196 return res;
199 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
200 unsigned long arg)
202 int error = 0;
203 struct snapshot_data *data;
204 loff_t size;
205 sector_t offset;
207 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
208 return -ENOTTY;
209 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
210 return -ENOTTY;
211 if (!capable(CAP_SYS_ADMIN))
212 return -EPERM;
214 if (!mutex_trylock(&pm_mutex))
215 return -EBUSY;
217 lock_device_hotplug();
218 data = filp->private_data;
220 switch (cmd) {
222 case SNAPSHOT_FREEZE:
223 if (data->frozen)
224 break;
226 printk("Syncing filesystems ... ");
227 sys_sync();
228 printk("done.\n");
230 error = freeze_processes();
231 if (error)
232 break;
234 error = create_basic_memory_bitmaps();
235 if (error)
236 thaw_processes();
237 else
238 data->frozen = true;
240 break;
242 case SNAPSHOT_UNFREEZE:
243 if (!data->frozen || data->ready)
244 break;
245 pm_restore_gfp_mask();
246 free_basic_memory_bitmaps();
247 data->free_bitmaps = false;
248 thaw_processes();
249 data->frozen = false;
250 break;
252 case SNAPSHOT_CREATE_IMAGE:
253 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
254 error = -EPERM;
255 break;
257 pm_restore_gfp_mask();
258 error = hibernation_snapshot(data->platform_support);
259 if (!error) {
260 error = put_user(in_suspend, (int __user *)arg);
261 data->ready = !freezer_test_done && !error;
262 freezer_test_done = false;
264 break;
266 case SNAPSHOT_ATOMIC_RESTORE:
267 snapshot_write_finalize(&data->handle);
268 if (data->mode != O_WRONLY || !data->frozen ||
269 !snapshot_image_loaded(&data->handle)) {
270 error = -EPERM;
271 break;
273 error = hibernation_restore(data->platform_support);
274 break;
276 case SNAPSHOT_FREE:
277 swsusp_free();
278 memset(&data->handle, 0, sizeof(struct snapshot_handle));
279 data->ready = false;
281 * It is necessary to thaw kernel threads here, because
282 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
283 * SNAPSHOT_FREE. In that case, if kernel threads were not
284 * thawed, the preallocation of memory carried out by
285 * hibernation_snapshot() might run into problems (i.e. it
286 * might fail or even deadlock).
288 thaw_kernel_threads();
289 break;
291 case SNAPSHOT_PREF_IMAGE_SIZE:
292 image_size = arg;
293 break;
295 case SNAPSHOT_GET_IMAGE_SIZE:
296 if (!data->ready) {
297 error = -ENODATA;
298 break;
300 size = snapshot_get_image_size();
301 size <<= PAGE_SHIFT;
302 error = put_user(size, (loff_t __user *)arg);
303 break;
305 case SNAPSHOT_AVAIL_SWAP_SIZE:
306 size = count_swap_pages(data->swap, 1);
307 size <<= PAGE_SHIFT;
308 error = put_user(size, (loff_t __user *)arg);
309 break;
311 case SNAPSHOT_ALLOC_SWAP_PAGE:
312 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
313 error = -ENODEV;
314 break;
316 offset = alloc_swapdev_block(data->swap);
317 if (offset) {
318 offset <<= PAGE_SHIFT;
319 error = put_user(offset, (loff_t __user *)arg);
320 } else {
321 error = -ENOSPC;
323 break;
325 case SNAPSHOT_FREE_SWAP_PAGES:
326 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
327 error = -ENODEV;
328 break;
330 free_all_swap_pages(data->swap);
331 break;
333 case SNAPSHOT_S2RAM:
334 if (!data->frozen) {
335 error = -EPERM;
336 break;
339 * Tasks are frozen and the notifiers have been called with
340 * PM_HIBERNATION_PREPARE
342 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
343 data->ready = false;
344 break;
346 case SNAPSHOT_PLATFORM_SUPPORT:
347 data->platform_support = !!arg;
348 break;
350 case SNAPSHOT_POWER_OFF:
351 if (data->platform_support)
352 error = hibernation_platform_enter();
353 break;
355 case SNAPSHOT_SET_SWAP_AREA:
356 if (swsusp_swap_in_use()) {
357 error = -EPERM;
358 } else {
359 struct resume_swap_area swap_area;
360 dev_t swdev;
362 error = copy_from_user(&swap_area, (void __user *)arg,
363 sizeof(struct resume_swap_area));
364 if (error) {
365 error = -EFAULT;
366 break;
370 * User space encodes device types as two-byte values,
371 * so we need to recode them
373 swdev = new_decode_dev(swap_area.dev);
374 if (swdev) {
375 offset = swap_area.offset;
376 data->swap = swap_type_of(swdev, offset, NULL);
377 if (data->swap < 0)
378 error = -ENODEV;
379 } else {
380 data->swap = -1;
381 error = -EINVAL;
384 break;
386 default:
387 error = -ENOTTY;
391 unlock_device_hotplug();
392 mutex_unlock(&pm_mutex);
394 return error;
397 #ifdef CONFIG_COMPAT
399 struct compat_resume_swap_area {
400 compat_loff_t offset;
401 u32 dev;
402 } __packed;
404 static long
405 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
407 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
409 switch (cmd) {
410 case SNAPSHOT_GET_IMAGE_SIZE:
411 case SNAPSHOT_AVAIL_SWAP_SIZE:
412 case SNAPSHOT_ALLOC_SWAP_PAGE: {
413 compat_loff_t __user *uoffset = compat_ptr(arg);
414 loff_t offset;
415 mm_segment_t old_fs;
416 int err;
418 old_fs = get_fs();
419 set_fs(KERNEL_DS);
420 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
421 set_fs(old_fs);
422 if (!err && put_user(offset, uoffset))
423 err = -EFAULT;
424 return err;
427 case SNAPSHOT_CREATE_IMAGE:
428 return snapshot_ioctl(file, cmd,
429 (unsigned long) compat_ptr(arg));
431 case SNAPSHOT_SET_SWAP_AREA: {
432 struct compat_resume_swap_area __user *u_swap_area =
433 compat_ptr(arg);
434 struct resume_swap_area swap_area;
435 mm_segment_t old_fs;
436 int err;
438 err = get_user(swap_area.offset, &u_swap_area->offset);
439 err |= get_user(swap_area.dev, &u_swap_area->dev);
440 if (err)
441 return -EFAULT;
442 old_fs = get_fs();
443 set_fs(KERNEL_DS);
444 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
445 (unsigned long) &swap_area);
446 set_fs(old_fs);
447 return err;
450 default:
451 return snapshot_ioctl(file, cmd, arg);
455 #endif /* CONFIG_COMPAT */
457 static const struct file_operations snapshot_fops = {
458 .open = snapshot_open,
459 .release = snapshot_release,
460 .read = snapshot_read,
461 .write = snapshot_write,
462 .llseek = no_llseek,
463 .unlocked_ioctl = snapshot_ioctl,
464 #ifdef CONFIG_COMPAT
465 .compat_ioctl = snapshot_compat_ioctl,
466 #endif
469 static struct miscdevice snapshot_device = {
470 .minor = SNAPSHOT_MINOR,
471 .name = "snapshot",
472 .fops = &snapshot_fops,
475 static int __init snapshot_device_init(void)
477 return misc_register(&snapshot_device);
480 device_initcall(snapshot_device_init);