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 <rjw@sisk.pl>
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/kmod.h>
16 #include <linux/string.h>
17 #include <linux/device.h>
18 #include <linux/miscdevice.h>
19 #include <linux/mm.h>
20 #include <linux/swap.h>
21 #include <linux/swapops.h>
22 #include <linux/pm.h>
23 #include <linux/fs.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>
29
30 #include <asm/uaccess.h>
31
32 #include "power.h"
33
34
35 #define SNAPSHOT_MINOR 231
36
37 static struct snapshot_data {
38 struct snapshot_handle handle;
39 int swap;
40 int mode;
41 char frozen;
42 char ready;
43 char platform_support;
44 } snapshot_state;
45
46 atomic_t snapshot_device_available = ATOMIC_INIT(1);
47
snapshot_open(struct inode * inode,struct file * filp)48 static int snapshot_open(struct inode *inode, struct file *filp)
49 {
50 struct snapshot_data *data;
51 int error;
52
53 lock_system_sleep();
54
55 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
56 error = -EBUSY;
57 goto Unlock;
58 }
59
60 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
61 atomic_inc(&snapshot_device_available);
62 error = -ENOSYS;
63 goto Unlock;
64 }
65 if(create_basic_memory_bitmaps()) {
66 atomic_inc(&snapshot_device_available);
67 error = -ENOMEM;
68 goto Unlock;
69 }
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);
80 if (error)
81 pm_notifier_call_chain(PM_POST_HIBERNATION);
82 } else {
83 /*
84 * Resuming. We may need to wait for the image device to
85 * appear.
86 */
87 wait_for_device_probe();
88 scsi_complete_async_scans();
89
90 data->swap = -1;
91 data->mode = O_WRONLY;
92 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
93 if (error)
94 pm_notifier_call_chain(PM_POST_RESTORE);
95 }
96 if (error) {
97 free_basic_memory_bitmaps();
98 atomic_inc(&snapshot_device_available);
99 }
100 data->frozen = 0;
101 data->ready = 0;
102 data->platform_support = 0;
103
104 Unlock:
105 unlock_system_sleep();
106
107 return error;
108 }
109
snapshot_release(struct inode * inode,struct file * filp)110 static int snapshot_release(struct inode *inode, struct file *filp)
111 {
112 struct snapshot_data *data;
113
114 lock_system_sleep();
115
116 swsusp_free();
117 free_basic_memory_bitmaps();
118 data = filp->private_data;
119 free_all_swap_pages(data->swap);
120 if (data->frozen) {
121 pm_restore_gfp_mask();
122 thaw_processes();
123 }
124 pm_notifier_call_chain(data->mode == O_RDONLY ?
125 PM_POST_HIBERNATION : PM_POST_RESTORE);
126 atomic_inc(&snapshot_device_available);
127
128 unlock_system_sleep();
129
130 return 0;
131 }
132
snapshot_read(struct file * filp,char __user * buf,size_t count,loff_t * offp)133 static ssize_t snapshot_read(struct file *filp, char __user *buf,
134 size_t count, loff_t *offp)
135 {
136 struct snapshot_data *data;
137 ssize_t res;
138 loff_t pg_offp = *offp & ~PAGE_MASK;
139
140 lock_system_sleep();
141
142 data = filp->private_data;
143 if (!data->ready) {
144 res = -ENODATA;
145 goto Unlock;
146 }
147 if (!pg_offp) { /* on page boundary? */
148 res = snapshot_read_next(&data->handle);
149 if (res <= 0)
150 goto Unlock;
151 } else {
152 res = PAGE_SIZE - pg_offp;
153 }
154
155 res = simple_read_from_buffer(buf, count, &pg_offp,
156 data_of(data->handle), res);
157 if (res > 0)
158 *offp += res;
159
160 Unlock:
161 unlock_system_sleep();
162
163 return res;
164 }
165
snapshot_write(struct file * filp,const char __user * buf,size_t count,loff_t * offp)166 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
167 size_t count, loff_t *offp)
168 {
169 struct snapshot_data *data;
170 ssize_t res;
171 loff_t pg_offp = *offp & ~PAGE_MASK;
172
173 lock_system_sleep();
174
175 data = filp->private_data;
176
177 if (!pg_offp) {
178 res = snapshot_write_next(&data->handle);
179 if (res <= 0)
180 goto unlock;
181 } else {
182 res = PAGE_SIZE - pg_offp;
183 }
184
185 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
186 buf, count);
187 if (res > 0)
188 *offp += res;
189 unlock:
190 unlock_system_sleep();
191
192 return res;
193 }
194
snapshot_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)195 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
196 unsigned long arg)
197 {
198 int error = 0;
199 struct snapshot_data *data;
200 loff_t size;
201 sector_t offset;
202
203 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
204 return -ENOTTY;
205 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
206 return -ENOTTY;
207 if (!capable(CAP_SYS_ADMIN))
208 return -EPERM;
209
210 if (!mutex_trylock(&pm_mutex))
211 return -EBUSY;
212
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 = usermodehelper_disable();
226 if (error)
227 break;
228
229 error = freeze_processes();
230 if (error)
231 usermodehelper_enable();
232 else
233 data->frozen = 1;
234 break;
235
236 case SNAPSHOT_UNFREEZE:
237 if (!data->frozen || data->ready)
238 break;
239 pm_restore_gfp_mask();
240 thaw_processes();
241 usermodehelper_enable();
242 data->frozen = 0;
243 break;
244
245 case SNAPSHOT_CREATE_IMAGE:
246 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
247 error = -EPERM;
248 break;
249 }
250 pm_restore_gfp_mask();
251 error = hibernation_snapshot(data->platform_support);
252 if (error) {
253 thaw_kernel_threads();
254 } else {
255 error = put_user(in_suspend, (int __user *)arg);
256 if (!error && !freezer_test_done)
257 data->ready = 1;
258 if (freezer_test_done) {
259 freezer_test_done = false;
260 thaw_kernel_threads();
261 }
262 }
263 break;
264
265 case SNAPSHOT_ATOMIC_RESTORE:
266 snapshot_write_finalize(&data->handle);
267 if (data->mode != O_WRONLY || !data->frozen ||
268 !snapshot_image_loaded(&data->handle)) {
269 error = -EPERM;
270 break;
271 }
272 error = hibernation_restore(data->platform_support);
273 break;
274
275 case SNAPSHOT_FREE:
276 swsusp_free();
277 memset(&data->handle, 0, sizeof(struct snapshot_handle));
278 data->ready = 0;
279 /*
280 * It is necessary to thaw kernel threads here, because
281 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
282 * SNAPSHOT_FREE. In that case, if kernel threads were not
283 * thawed, the preallocation of memory carried out by
284 * hibernation_snapshot() might run into problems (i.e. it
285 * might fail or even deadlock).
286 */
287 thaw_kernel_threads();
288 break;
289
290 case SNAPSHOT_PREF_IMAGE_SIZE:
291 image_size = arg;
292 break;
293
294 case SNAPSHOT_GET_IMAGE_SIZE:
295 if (!data->ready) {
296 error = -ENODATA;
297 break;
298 }
299 size = snapshot_get_image_size();
300 size <<= PAGE_SHIFT;
301 error = put_user(size, (loff_t __user *)arg);
302 break;
303
304 case SNAPSHOT_AVAIL_SWAP_SIZE:
305 size = count_swap_pages(data->swap, 1);
306 size <<= PAGE_SHIFT;
307 error = put_user(size, (loff_t __user *)arg);
308 break;
309
310 case SNAPSHOT_ALLOC_SWAP_PAGE:
311 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
312 error = -ENODEV;
313 break;
314 }
315 offset = alloc_swapdev_block(data->swap);
316 if (offset) {
317 offset <<= PAGE_SHIFT;
318 error = put_user(offset, (loff_t __user *)arg);
319 } else {
320 error = -ENOSPC;
321 }
322 break;
323
324 case SNAPSHOT_FREE_SWAP_PAGES:
325 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
326 error = -ENODEV;
327 break;
328 }
329 free_all_swap_pages(data->swap);
330 break;
331
332 case SNAPSHOT_S2RAM:
333 if (!data->frozen) {
334 error = -EPERM;
335 break;
336 }
337 /*
338 * Tasks are frozen and the notifiers have been called with
339 * PM_HIBERNATION_PREPARE
340 */
341 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
342 data->ready = 0;
343 break;
344
345 case SNAPSHOT_PLATFORM_SUPPORT:
346 data->platform_support = !!arg;
347 break;
348
349 case SNAPSHOT_POWER_OFF:
350 if (data->platform_support)
351 error = hibernation_platform_enter();
352 break;
353
354 case SNAPSHOT_SET_SWAP_AREA:
355 if (swsusp_swap_in_use()) {
356 error = -EPERM;
357 } else {
358 struct resume_swap_area swap_area;
359 dev_t swdev;
360
361 error = copy_from_user(&swap_area, (void __user *)arg,
362 sizeof(struct resume_swap_area));
363 if (error) {
364 error = -EFAULT;
365 break;
366 }
367
368 /*
369 * User space encodes device types as two-byte values,
370 * so we need to recode them
371 */
372 swdev = new_decode_dev(swap_area.dev);
373 if (swdev) {
374 offset = swap_area.offset;
375 data->swap = swap_type_of(swdev, offset, NULL);
376 if (data->swap < 0)
377 error = -ENODEV;
378 } else {
379 data->swap = -1;
380 error = -EINVAL;
381 }
382 }
383 break;
384
385 default:
386 error = -ENOTTY;
387
388 }
389
390 mutex_unlock(&pm_mutex);
391
392 return error;
393 }
394
395 #ifdef CONFIG_COMPAT
396
397 struct compat_resume_swap_area {
398 compat_loff_t offset;
399 u32 dev;
400 } __packed;
401
402 static long
snapshot_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)403 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
404 {
405 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
406
407 switch (cmd) {
408 case SNAPSHOT_GET_IMAGE_SIZE:
409 case SNAPSHOT_AVAIL_SWAP_SIZE:
410 case SNAPSHOT_ALLOC_SWAP_PAGE: {
411 compat_loff_t __user *uoffset = compat_ptr(arg);
412 loff_t offset;
413 mm_segment_t old_fs;
414 int err;
415
416 old_fs = get_fs();
417 set_fs(KERNEL_DS);
418 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
419 set_fs(old_fs);
420 if (!err && put_user(offset, uoffset))
421 err = -EFAULT;
422 return err;
423 }
424
425 case SNAPSHOT_CREATE_IMAGE:
426 return snapshot_ioctl(file, cmd,
427 (unsigned long) compat_ptr(arg));
428
429 case SNAPSHOT_SET_SWAP_AREA: {
430 struct compat_resume_swap_area __user *u_swap_area =
431 compat_ptr(arg);
432 struct resume_swap_area swap_area;
433 mm_segment_t old_fs;
434 int err;
435
436 err = get_user(swap_area.offset, &u_swap_area->offset);
437 err |= get_user(swap_area.dev, &u_swap_area->dev);
438 if (err)
439 return -EFAULT;
440 old_fs = get_fs();
441 set_fs(KERNEL_DS);
442 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
443 (unsigned long) &swap_area);
444 set_fs(old_fs);
445 return err;
446 }
447
448 default:
449 return snapshot_ioctl(file, cmd, arg);
450 }
451 }
452
453 #endif /* CONFIG_COMPAT */
454
455 static const struct file_operations snapshot_fops = {
456 .open = snapshot_open,
457 .release = snapshot_release,
458 .read = snapshot_read,
459 .write = snapshot_write,
460 .llseek = no_llseek,
461 .unlocked_ioctl = snapshot_ioctl,
462 #ifdef CONFIG_COMPAT
463 .compat_ioctl = snapshot_compat_ioctl,
464 #endif
465 };
466
467 static struct miscdevice snapshot_device = {
468 .minor = SNAPSHOT_MINOR,
469 .name = "snapshot",
470 .fops = &snapshot_fops,
471 };
472
snapshot_device_init(void)473 static int __init snapshot_device_init(void)
474 {
475 return misc_register(&snapshot_device);
476 };
477
478 device_initcall(snapshot_device_init);
479