projects/linux·blob v3.7 · refs

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1/*
2 * linux/kernel/power/user.c
3 *
4 * This file provides the user space interface for software suspend/resume.
5 *
6 * Copyright (C) 2006 Rafael J. Wysocki <[email protected]>
7 *
8 * This file is released under the GPLv2.
9 *
10 */
11
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>
27
28#include <asm/uaccess.h>
29
30#include "power.h"
31
32
33#define SNAPSHOT_MINOR 231
34
35static struct snapshot_data {
36 struct snapshot_handle handle;
37 int swap;
38 int mode;
39 char frozen;
40 char ready;
41 char platform_support;
42} snapshot_state;
43
44atomic_t snapshot_device_available = ATOMIC_INIT(1);
45
46static int snapshot_open(struct inode *inode, struct file *filp)
47{
48 struct snapshot_data *data;
49 int error;
50
51 lock_system_sleep();
52
53 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
54 error = -EBUSY;
55 goto Unlock;
56 }
57
58 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
59 atomic_inc(&snapshot_device_available);
60 error = -ENOSYS;
61 goto Unlock;
62 }
63 if(create_basic_memory_bitmaps()) {
64 atomic_inc(&snapshot_device_available);
65 error = -ENOMEM;
66 goto Unlock;
67 }
68 nonseekable_open(inode, filp);
69 data = &snapshot_state;
70 filp->private_data = data;
71 memset(&data->handle, 0, sizeof(struct snapshot_handle));
72 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
73 /* Hibernating. The image device should be accessible. */
74 data->swap = swsusp_resume_device ?
75 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
76 data->mode = O_RDONLY;
77 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
78 if (error)
79 pm_notifier_call_chain(PM_POST_HIBERNATION);
80 } else {
81 /*
82 * Resuming. We may need to wait for the image device to
83 * appear.
84 */
85 wait_for_device_probe();
86
87 data->swap = -1;
88 data->mode = O_WRONLY;
89 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
90 if (error)
91 pm_notifier_call_chain(PM_POST_RESTORE);
92 }
93 if (error) {
94 free_basic_memory_bitmaps();
95 atomic_inc(&snapshot_device_available);
96 }
97 data->frozen = 0;
98 data->ready = 0;
99 data->platform_support = 0;
100
101 Unlock:
102 unlock_system_sleep();
103
104 return error;
105}
106
107static int snapshot_release(struct inode *inode, struct file *filp)
108{
109 struct snapshot_data *data;
110
111 lock_system_sleep();
112
113 swsusp_free();
114 free_basic_memory_bitmaps();
115 data = filp->private_data;
116 free_all_swap_pages(data->swap);
117 if (data->frozen) {
118 pm_restore_gfp_mask();
119 thaw_processes();
120 }
121 pm_notifier_call_chain(data->mode == O_RDONLY ?
122 PM_POST_HIBERNATION : PM_POST_RESTORE);
123 atomic_inc(&snapshot_device_available);
124
125 unlock_system_sleep();
126
127 return 0;
128}
129
130static ssize_t snapshot_read(struct file *filp, char __user *buf,
131 size_t count, loff_t *offp)
132{
133 struct snapshot_data *data;
134 ssize_t res;
135 loff_t pg_offp = *offp & ~PAGE_MASK;
136
137 lock_system_sleep();
138
139 data = filp->private_data;
140 if (!data->ready) {
141 res = -ENODATA;
142 goto Unlock;
143 }
144 if (!pg_offp) { /* on page boundary? */
145 res = snapshot_read_next(&data->handle);
146 if (res <= 0)
147 goto Unlock;
148 } else {
149 res = PAGE_SIZE - pg_offp;
150 }
151
152 res = simple_read_from_buffer(buf, count, &pg_offp,
153 data_of(data->handle), res);
154 if (res > 0)
155 *offp += res;
156
157 Unlock:
158 unlock_system_sleep();
159
160 return res;
161}
162
163static ssize_t snapshot_write(struct file *filp, const char __user *buf,
164 size_t count, loff_t *offp)
165{
166 struct snapshot_data *data;
167 ssize_t res;
168 loff_t pg_offp = *offp & ~PAGE_MASK;
169
170 lock_system_sleep();
171
172 data = filp->private_data;
173
174 if (!pg_offp) {
175 res = snapshot_write_next(&data->handle);
176 if (res <= 0)
177 goto unlock;
178 } else {
179 res = PAGE_SIZE - pg_offp;
180 }
181
182 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
183 buf, count);
184 if (res > 0)
185 *offp += res;
186unlock:
187 unlock_system_sleep();
188
189 return res;
190}
191
192static long snapshot_ioctl(struct file *filp, unsigned int cmd,
193 unsigned long arg)
194{
195 int error = 0;
196 struct snapshot_data *data;
197 loff_t size;
198 sector_t offset;
199
200 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
201 return -ENOTTY;
202 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
203 return -ENOTTY;
204 if (!capable(CAP_SYS_ADMIN))
205 return -EPERM;
206
207 if (!mutex_trylock(&pm_mutex))
208 return -EBUSY;
209
210 data = filp->private_data;
211
212 switch (cmd) {
213
214 case SNAPSHOT_FREEZE:
215 if (data->frozen)
216 break;
217
218 printk("Syncing filesystems ... ");
219 sys_sync();
220 printk("done.\n");
221
222 error = freeze_processes();
223 if (!error)
224 data->frozen = 1;
225 break;
226
227 case SNAPSHOT_UNFREEZE:
228 if (!data->frozen || data->ready)
229 break;
230 pm_restore_gfp_mask();
231 thaw_processes();
232 data->frozen = 0;
233 break;
234
235 case SNAPSHOT_CREATE_IMAGE:
236 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
237 error = -EPERM;
238 break;
239 }
240 pm_restore_gfp_mask();
241 error = hibernation_snapshot(data->platform_support);
242 if (!error) {
243 error = put_user(in_suspend, (int __user *)arg);
244 data->ready = !freezer_test_done && !error;
245 freezer_test_done = false;
246 }
247 break;
248
249 case SNAPSHOT_ATOMIC_RESTORE:
250 snapshot_write_finalize(&data->handle);
251 if (data->mode != O_WRONLY || !data->frozen ||
252 !snapshot_image_loaded(&data->handle)) {
253 error = -EPERM;
254 break;
255 }
256 error = hibernation_restore(data->platform_support);
257 break;
258
259 case SNAPSHOT_FREE:
260 swsusp_free();
261 memset(&data->handle, 0, sizeof(struct snapshot_handle));
262 data->ready = 0;
263 /*
264 * It is necessary to thaw kernel threads here, because
265 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
266 * SNAPSHOT_FREE. In that case, if kernel threads were not
267 * thawed, the preallocation of memory carried out by
268 * hibernation_snapshot() might run into problems (i.e. it
269 * might fail or even deadlock).
270 */
271 thaw_kernel_threads();
272 break;
273
274 case SNAPSHOT_PREF_IMAGE_SIZE:
275 image_size = arg;
276 break;
277
278 case SNAPSHOT_GET_IMAGE_SIZE:
279 if (!data->ready) {
280 error = -ENODATA;
281 break;
282 }
283 size = snapshot_get_image_size();
284 size <<= PAGE_SHIFT;
285 error = put_user(size, (loff_t __user *)arg);
286 break;
287
288 case SNAPSHOT_AVAIL_SWAP_SIZE:
289 size = count_swap_pages(data->swap, 1);
290 size <<= PAGE_SHIFT;
291 error = put_user(size, (loff_t __user *)arg);
292 break;
293
294 case SNAPSHOT_ALLOC_SWAP_PAGE:
295 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
296 error = -ENODEV;
297 break;
298 }
299 offset = alloc_swapdev_block(data->swap);
300 if (offset) {
301 offset <<= PAGE_SHIFT;
302 error = put_user(offset, (loff_t __user *)arg);
303 } else {
304 error = -ENOSPC;
305 }
306 break;
307
308 case SNAPSHOT_FREE_SWAP_PAGES:
309 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
310 error = -ENODEV;
311 break;
312 }
313 free_all_swap_pages(data->swap);
314 break;
315
316 case SNAPSHOT_S2RAM:
317 if (!data->frozen) {
318 error = -EPERM;
319 break;
320 }
321 /*
322 * Tasks are frozen and the notifiers have been called with
323 * PM_HIBERNATION_PREPARE
324 */
325 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
326 data->ready = 0;
327 break;
328
329 case SNAPSHOT_PLATFORM_SUPPORT:
330 data->platform_support = !!arg;
331 break;
332
333 case SNAPSHOT_POWER_OFF:
334 if (data->platform_support)
335 error = hibernation_platform_enter();
336 break;
337
338 case SNAPSHOT_SET_SWAP_AREA:
339 if (swsusp_swap_in_use()) {
340 error = -EPERM;
341 } else {
342 struct resume_swap_area swap_area;
343 dev_t swdev;
344
345 error = copy_from_user(&swap_area, (void __user *)arg,
346 sizeof(struct resume_swap_area));
347 if (error) {
348 error = -EFAULT;
349 break;
350 }
351
352 /*
353 * User space encodes device types as two-byte values,
354 * so we need to recode them
355 */
356 swdev = new_decode_dev(swap_area.dev);
357 if (swdev) {
358 offset = swap_area.offset;
359 data->swap = swap_type_of(swdev, offset, NULL);
360 if (data->swap < 0)
361 error = -ENODEV;
362 } else {
363 data->swap = -1;
364 error = -EINVAL;
365 }
366 }
367 break;
368
369 default:
370 error = -ENOTTY;
371
372 }
373
374 mutex_unlock(&pm_mutex);
375
376 return error;
377}
378
379#ifdef CONFIG_COMPAT
380
381struct compat_resume_swap_area {
382 compat_loff_t offset;
383 u32 dev;
384} __packed;
385
386static long
387snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
388{
389 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
390
391 switch (cmd) {
392 case SNAPSHOT_GET_IMAGE_SIZE:
393 case SNAPSHOT_AVAIL_SWAP_SIZE:
394 case SNAPSHOT_ALLOC_SWAP_PAGE: {
395 compat_loff_t __user *uoffset = compat_ptr(arg);
396 loff_t offset;
397 mm_segment_t old_fs;
398 int err;
399
400 old_fs = get_fs();
401 set_fs(KERNEL_DS);
402 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
403 set_fs(old_fs);
404 if (!err && put_user(offset, uoffset))
405 err = -EFAULT;
406 return err;
407 }
408
409 case SNAPSHOT_CREATE_IMAGE:
410 return snapshot_ioctl(file, cmd,
411 (unsigned long) compat_ptr(arg));
412
413 case SNAPSHOT_SET_SWAP_AREA: {
414 struct compat_resume_swap_area __user *u_swap_area =
415 compat_ptr(arg);
416 struct resume_swap_area swap_area;
417 mm_segment_t old_fs;
418 int err;
419
420 err = get_user(swap_area.offset, &u_swap_area->offset);
421 err |= get_user(swap_area.dev, &u_swap_area->dev);
422 if (err)
423 return -EFAULT;
424 old_fs = get_fs();
425 set_fs(KERNEL_DS);
426 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
427 (unsigned long) &swap_area);
428 set_fs(old_fs);
429 return err;
430 }
431
432 default:
433 return snapshot_ioctl(file, cmd, arg);
434 }
435}
436
437#endif /* CONFIG_COMPAT */
438
439static const struct file_operations snapshot_fops = {
440 .open = snapshot_open,
441 .release = snapshot_release,
442 .read = snapshot_read,
443 .write = snapshot_write,
444 .llseek = no_llseek,
445 .unlocked_ioctl = snapshot_ioctl,
446#ifdef CONFIG_COMPAT
447 .compat_ioctl = snapshot_compat_ioctl,
448#endif
449};
450
451static struct miscdevice snapshot_device = {
452 .minor = SNAPSHOT_MINOR,
453 .name = "snapshot",
454 .fops = &snapshot_fops,
455};
456
457static int __init snapshot_device_init(void)
458{
459 return misc_register(&snapshot_device);
460};
461
462device_initcall(snapshot_device_init);