projects/linux·blob v3.13 · refs

475 lines · 9.9 KiB

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 bool frozen;
40 bool ready;
41 bool platform_support;
42 bool free_bitmaps;
43} snapshot_state;
44
45atomic_t snapshot_device_available = ATOMIC_INIT(1);
46
47static int snapshot_open(struct inode *inode, struct file *filp)
48{
49 struct snapshot_data *data;
50 int error;
51
52 lock_system_sleep();
53
54 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
55 error = -EBUSY;
56 goto Unlock;
57 }
58
59 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
60 atomic_inc(&snapshot_device_available);
61 error = -ENOSYS;
62 goto Unlock;
63 }
64 nonseekable_open(inode, filp);
65 data = &snapshot_state;
66 filp->private_data = data;
67 memset(&data->handle, 0, sizeof(struct snapshot_handle));
68 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
69 /* Hibernating. The image device should be accessible. */
70 data->swap = swsusp_resume_device ?
71 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
72 data->mode = O_RDONLY;
73 data->free_bitmaps = false;
74 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
75 if (error)
76 pm_notifier_call_chain(PM_POST_HIBERNATION);
77 } else {
78 /*
79 * Resuming. We may need to wait for the image device to
80 * appear.
81 */
82 wait_for_device_probe();
83
84 data->swap = -1;
85 data->mode = O_WRONLY;
86 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
87 if (!error) {
88 error = create_basic_memory_bitmaps();
89 data->free_bitmaps = !error;
90 }
91 if (error)
92 pm_notifier_call_chain(PM_POST_RESTORE);
93 }
94 if (error)
95 atomic_inc(&snapshot_device_available);
96
97 data->frozen = false;
98 data->ready = false;
99 data->platform_support = false;
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 data = filp->private_data;
115 free_all_swap_pages(data->swap);
116 if (data->frozen) {
117 pm_restore_gfp_mask();
118 free_basic_memory_bitmaps();
119 thaw_processes();
120 } else if (data->free_bitmaps) {
121 free_basic_memory_bitmaps();
122 }
123 pm_notifier_call_chain(data->mode == O_RDONLY ?
124 PM_POST_HIBERNATION : PM_POST_RESTORE);
125 atomic_inc(&snapshot_device_available);
126
127 unlock_system_sleep();
128
129 return 0;
130}
131
132static ssize_t snapshot_read(struct file *filp, char __user *buf,
133 size_t count, loff_t *offp)
134{
135 struct snapshot_data *data;
136 ssize_t res;
137 loff_t pg_offp = *offp & ~PAGE_MASK;
138
139 lock_system_sleep();
140
141 data = filp->private_data;
142 if (!data->ready) {
143 res = -ENODATA;
144 goto Unlock;
145 }
146 if (!pg_offp) { /* on page boundary? */
147 res = snapshot_read_next(&data->handle);
148 if (res <= 0)
149 goto Unlock;
150 } else {
151 res = PAGE_SIZE - pg_offp;
152 }
153
154 res = simple_read_from_buffer(buf, count, &pg_offp,
155 data_of(data->handle), res);
156 if (res > 0)
157 *offp += res;
158
159 Unlock:
160 unlock_system_sleep();
161
162 return res;
163}
164
165static ssize_t snapshot_write(struct file *filp, const char __user *buf,
166 size_t count, loff_t *offp)
167{
168 struct snapshot_data *data;
169 ssize_t res;
170 loff_t pg_offp = *offp & ~PAGE_MASK;
171
172 lock_system_sleep();
173
174 data = filp->private_data;
175
176 if (!pg_offp) {
177 res = snapshot_write_next(&data->handle);
178 if (res <= 0)
179 goto unlock;
180 } else {
181 res = PAGE_SIZE - pg_offp;
182 }
183
184 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
185 buf, count);
186 if (res > 0)
187 *offp += res;
188unlock:
189 unlock_system_sleep();
190
191 return res;
192}
193
194static long snapshot_ioctl(struct file *filp, unsigned int cmd,
195 unsigned long arg)
196{
197 int error = 0;
198 struct snapshot_data *data;
199 loff_t size;
200 sector_t offset;
201
202 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
203 return -ENOTTY;
204 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
205 return -ENOTTY;
206 if (!capable(CAP_SYS_ADMIN))
207 return -EPERM;
208
209 if (!mutex_trylock(&pm_mutex))
210 return -EBUSY;
211
212 lock_device_hotplug();
213 data = filp->private_data;
214
215 switch (cmd) {
216
217 case SNAPSHOT_FREEZE:
218 if (data->frozen)
219 break;
220
221 printk("Syncing filesystems ... ");
222 sys_sync();
223 printk("done.\n");
224
225 error = freeze_processes();
226 if (error)
227 break;
228
229 error = create_basic_memory_bitmaps();
230 if (error)
231 thaw_processes();
232 else
233 data->frozen = true;
234
235 break;
236
237 case SNAPSHOT_UNFREEZE:
238 if (!data->frozen || data->ready)
239 break;
240 pm_restore_gfp_mask();
241 free_basic_memory_bitmaps();
242 data->free_bitmaps = false;
243 thaw_processes();
244 data->frozen = false;
245 break;
246
247 case SNAPSHOT_CREATE_IMAGE:
248 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
249 error = -EPERM;
250 break;
251 }
252 pm_restore_gfp_mask();
253 error = hibernation_snapshot(data->platform_support);
254 if (!error) {
255 error = put_user(in_suspend, (int __user *)arg);
256 data->ready = !freezer_test_done && !error;
257 freezer_test_done = false;
258 }
259 break;
260
261 case SNAPSHOT_ATOMIC_RESTORE:
262 snapshot_write_finalize(&data->handle);
263 if (data->mode != O_WRONLY || !data->frozen ||
264 !snapshot_image_loaded(&data->handle)) {
265 error = -EPERM;
266 break;
267 }
268 error = hibernation_restore(data->platform_support);
269 break;
270
271 case SNAPSHOT_FREE:
272 swsusp_free();
273 memset(&data->handle, 0, sizeof(struct snapshot_handle));
274 data->ready = false;
275 /*
276 * It is necessary to thaw kernel threads here, because
277 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
278 * SNAPSHOT_FREE. In that case, if kernel threads were not
279 * thawed, the preallocation of memory carried out by
280 * hibernation_snapshot() might run into problems (i.e. it
281 * might fail or even deadlock).
282 */
283 thaw_kernel_threads();
284 break;
285
286 case SNAPSHOT_PREF_IMAGE_SIZE:
287 image_size = arg;
288 break;
289
290 case SNAPSHOT_GET_IMAGE_SIZE:
291 if (!data->ready) {
292 error = -ENODATA;
293 break;
294 }
295 size = snapshot_get_image_size();
296 size <<= PAGE_SHIFT;
297 error = put_user(size, (loff_t __user *)arg);
298 break;
299
300 case SNAPSHOT_AVAIL_SWAP_SIZE:
301 size = count_swap_pages(data->swap, 1);
302 size <<= PAGE_SHIFT;
303 error = put_user(size, (loff_t __user *)arg);
304 break;
305
306 case SNAPSHOT_ALLOC_SWAP_PAGE:
307 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
308 error = -ENODEV;
309 break;
310 }
311 offset = alloc_swapdev_block(data->swap);
312 if (offset) {
313 offset <<= PAGE_SHIFT;
314 error = put_user(offset, (loff_t __user *)arg);
315 } else {
316 error = -ENOSPC;
317 }
318 break;
319
320 case SNAPSHOT_FREE_SWAP_PAGES:
321 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
322 error = -ENODEV;
323 break;
324 }
325 free_all_swap_pages(data->swap);
326 break;
327
328 case SNAPSHOT_S2RAM:
329 if (!data->frozen) {
330 error = -EPERM;
331 break;
332 }
333 /*
334 * Tasks are frozen and the notifiers have been called with
335 * PM_HIBERNATION_PREPARE
336 */
337 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
338 data->ready = false;
339 break;
340
341 case SNAPSHOT_PLATFORM_SUPPORT:
342 data->platform_support = !!arg;
343 break;
344
345 case SNAPSHOT_POWER_OFF:
346 if (data->platform_support)
347 error = hibernation_platform_enter();
348 break;
349
350 case SNAPSHOT_SET_SWAP_AREA:
351 if (swsusp_swap_in_use()) {
352 error = -EPERM;
353 } else {
354 struct resume_swap_area swap_area;
355 dev_t swdev;
356
357 error = copy_from_user(&swap_area, (void __user *)arg,
358 sizeof(struct resume_swap_area));
359 if (error) {
360 error = -EFAULT;
361 break;
362 }
363
364 /*
365 * User space encodes device types as two-byte values,
366 * so we need to recode them
367 */
368 swdev = new_decode_dev(swap_area.dev);
369 if (swdev) {
370 offset = swap_area.offset;
371 data->swap = swap_type_of(swdev, offset, NULL);
372 if (data->swap < 0)
373 error = -ENODEV;
374 } else {
375 data->swap = -1;
376 error = -EINVAL;
377 }
378 }
379 break;
380
381 default:
382 error = -ENOTTY;
383
384 }
385
386 unlock_device_hotplug();
387 mutex_unlock(&pm_mutex);
388
389 return error;
390}
391
392#ifdef CONFIG_COMPAT
393
394struct compat_resume_swap_area {
395 compat_loff_t offset;
396 u32 dev;
397} __packed;
398
399static long
400snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
401{
402 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
403
404 switch (cmd) {
405 case SNAPSHOT_GET_IMAGE_SIZE:
406 case SNAPSHOT_AVAIL_SWAP_SIZE:
407 case SNAPSHOT_ALLOC_SWAP_PAGE: {
408 compat_loff_t __user *uoffset = compat_ptr(arg);
409 loff_t offset;
410 mm_segment_t old_fs;
411 int err;
412
413 old_fs = get_fs();
414 set_fs(KERNEL_DS);
415 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
416 set_fs(old_fs);
417 if (!err && put_user(offset, uoffset))
418 err = -EFAULT;
419 return err;
420 }
421
422 case SNAPSHOT_CREATE_IMAGE:
423 return snapshot_ioctl(file, cmd,
424 (unsigned long) compat_ptr(arg));
425
426 case SNAPSHOT_SET_SWAP_AREA: {
427 struct compat_resume_swap_area __user *u_swap_area =
428 compat_ptr(arg);
429 struct resume_swap_area swap_area;
430 mm_segment_t old_fs;
431 int err;
432
433 err = get_user(swap_area.offset, &u_swap_area->offset);
434 err |= get_user(swap_area.dev, &u_swap_area->dev);
435 if (err)
436 return -EFAULT;
437 old_fs = get_fs();
438 set_fs(KERNEL_DS);
439 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
440 (unsigned long) &swap_area);
441 set_fs(old_fs);
442 return err;
443 }
444
445 default:
446 return snapshot_ioctl(file, cmd, arg);
447 }
448}
449
450#endif /* CONFIG_COMPAT */
451
452static const struct file_operations snapshot_fops = {
453 .open = snapshot_open,
454 .release = snapshot_release,
455 .read = snapshot_read,
456 .write = snapshot_write,
457 .llseek = no_llseek,
458 .unlocked_ioctl = snapshot_ioctl,
459#ifdef CONFIG_COMPAT
460 .compat_ioctl = snapshot_compat_ioctl,
461#endif
462};
463
464static struct miscdevice snapshot_device = {
465 .minor = SNAPSHOT_MINOR,
466 .name = "snapshot",
467 .fops = &snapshot_fops,
468};
469
470static int __init snapshot_device_init(void)
471{
472 return misc_register(&snapshot_device);
473};
474
475device_initcall(snapshot_device_init);