GNU Linux-libre 4.19.211-gnu1
[releases.git] / kernel / power / user.c
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/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 <linux/uaccess.h>
29
30 #include "power.h"
31
32
33 #define SNAPSHOT_MINOR  231
34
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;
44
45 atomic_t snapshot_device_available = ATOMIC_INIT(1);
46
47 static int snapshot_open(struct inode *inode, struct file *filp)
48 {
49         struct snapshot_data *data;
50         int error, nr_calls = 0;
51
52         if (!hibernation_available())
53                 return -EPERM;
54
55         lock_system_sleep();
56
57         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
58                 error = -EBUSY;
59                 goto Unlock;
60         }
61
62         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
63                 atomic_inc(&snapshot_device_available);
64                 error = -ENOSYS;
65                 goto Unlock;
66         }
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 {
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, -1, &nr_calls);
90                 if (!error) {
91                         error = create_basic_memory_bitmaps();
92                         data->free_bitmaps = !error;
93                 } else
94                         nr_calls--;
95
96                 if (error)
97                         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
98         }
99         if (error)
100                 atomic_inc(&snapshot_device_available);
101
102         data->frozen = false;
103         data->ready = false;
104         data->platform_support = false;
105
106  Unlock:
107         unlock_system_sleep();
108
109         return error;
110 }
111
112 static int snapshot_release(struct inode *inode, struct file *filp)
113 {
114         struct snapshot_data *data;
115
116         lock_system_sleep();
117
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();
127         }
128         pm_notifier_call_chain(data->mode == O_RDONLY ?
129                         PM_POST_HIBERNATION : PM_POST_RESTORE);
130         atomic_inc(&snapshot_device_available);
131
132         unlock_system_sleep();
133
134         return 0;
135 }
136
137 static ssize_t snapshot_read(struct file *filp, char __user *buf,
138                              size_t count, loff_t *offp)
139 {
140         struct snapshot_data *data;
141         ssize_t res;
142         loff_t pg_offp = *offp & ~PAGE_MASK;
143
144         lock_system_sleep();
145
146         data = filp->private_data;
147         if (!data->ready) {
148                 res = -ENODATA;
149                 goto Unlock;
150         }
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;
157         }
158
159         res = simple_read_from_buffer(buf, count, &pg_offp,
160                         data_of(data->handle), res);
161         if (res > 0)
162                 *offp += res;
163
164  Unlock:
165         unlock_system_sleep();
166
167         return res;
168 }
169
170 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
171                               size_t count, loff_t *offp)
172 {
173         struct snapshot_data *data;
174         ssize_t res;
175         loff_t pg_offp = *offp & ~PAGE_MASK;
176
177         lock_system_sleep();
178
179         data = filp->private_data;
180
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;
187         }
188
189         if (!data_of(data->handle)) {
190                 res = -EINVAL;
191                 goto unlock;
192         }
193
194         res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
195                         buf, count);
196         if (res > 0)
197                 *offp += res;
198 unlock:
199         unlock_system_sleep();
200
201         return res;
202 }
203
204 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
205                                                         unsigned long arg)
206 {
207         int error = 0;
208         struct snapshot_data *data;
209         loff_t size;
210         sector_t offset;
211
212         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
213                 return -ENOTTY;
214         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
215                 return -ENOTTY;
216         if (!capable(CAP_SYS_ADMIN))
217                 return -EPERM;
218
219         if (!mutex_trylock(&system_transition_mutex))
220                 return -EBUSY;
221
222         lock_device_hotplug();
223         data = filp->private_data;
224
225         switch (cmd) {
226
227         case SNAPSHOT_FREEZE:
228                 if (data->frozen)
229                         break;
230
231                 printk("Syncing filesystems ... ");
232                 ksys_sync();
233                 printk("done.\n");
234
235                 error = freeze_processes();
236                 if (error)
237                         break;
238
239                 error = create_basic_memory_bitmaps();
240                 if (error)
241                         thaw_processes();
242                 else
243                         data->frozen = true;
244
245                 break;
246
247         case SNAPSHOT_UNFREEZE:
248                 if (!data->frozen || data->ready)
249                         break;
250                 pm_restore_gfp_mask();
251                 free_basic_memory_bitmaps();
252                 data->free_bitmaps = false;
253                 thaw_processes();
254                 data->frozen = false;
255                 break;
256
257         case SNAPSHOT_CREATE_IMAGE:
258                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
259                         error = -EPERM;
260                         break;
261                 }
262                 pm_restore_gfp_mask();
263                 error = hibernation_snapshot(data->platform_support);
264                 if (!error) {
265                         error = put_user(in_suspend, (int __user *)arg);
266                         data->ready = !freezer_test_done && !error;
267                         freezer_test_done = false;
268                 }
269                 break;
270
271         case SNAPSHOT_ATOMIC_RESTORE:
272                 snapshot_write_finalize(&data->handle);
273                 if (data->mode != O_WRONLY || !data->frozen ||
274                     !snapshot_image_loaded(&data->handle)) {
275                         error = -EPERM;
276                         break;
277                 }
278                 error = hibernation_restore(data->platform_support);
279                 break;
280
281         case SNAPSHOT_FREE:
282                 swsusp_free();
283                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
284                 data->ready = false;
285                 /*
286                  * It is necessary to thaw kernel threads here, because
287                  * SNAPSHOT_CREATE_IMAGE may be invoked directly after
288                  * SNAPSHOT_FREE.  In that case, if kernel threads were not
289                  * thawed, the preallocation of memory carried out by
290                  * hibernation_snapshot() might run into problems (i.e. it
291                  * might fail or even deadlock).
292                  */
293                 thaw_kernel_threads();
294                 break;
295
296         case SNAPSHOT_PREF_IMAGE_SIZE:
297                 image_size = arg;
298                 break;
299
300         case SNAPSHOT_GET_IMAGE_SIZE:
301                 if (!data->ready) {
302                         error = -ENODATA;
303                         break;
304                 }
305                 size = snapshot_get_image_size();
306                 size <<= PAGE_SHIFT;
307                 error = put_user(size, (loff_t __user *)arg);
308                 break;
309
310         case SNAPSHOT_AVAIL_SWAP_SIZE:
311                 size = count_swap_pages(data->swap, 1);
312                 size <<= PAGE_SHIFT;
313                 error = put_user(size, (loff_t __user *)arg);
314                 break;
315
316         case SNAPSHOT_ALLOC_SWAP_PAGE:
317                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
318                         error = -ENODEV;
319                         break;
320                 }
321                 offset = alloc_swapdev_block(data->swap);
322                 if (offset) {
323                         offset <<= PAGE_SHIFT;
324                         error = put_user(offset, (loff_t __user *)arg);
325                 } else {
326                         error = -ENOSPC;
327                 }
328                 break;
329
330         case SNAPSHOT_FREE_SWAP_PAGES:
331                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
332                         error = -ENODEV;
333                         break;
334                 }
335                 free_all_swap_pages(data->swap);
336                 break;
337
338         case SNAPSHOT_S2RAM:
339                 if (!data->frozen) {
340                         error = -EPERM;
341                         break;
342                 }
343                 /*
344                  * Tasks are frozen and the notifiers have been called with
345                  * PM_HIBERNATION_PREPARE
346                  */
347                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
348                 data->ready = false;
349                 break;
350
351         case SNAPSHOT_PLATFORM_SUPPORT:
352                 data->platform_support = !!arg;
353                 break;
354
355         case SNAPSHOT_POWER_OFF:
356                 if (data->platform_support)
357                         error = hibernation_platform_enter();
358                 break;
359
360         case SNAPSHOT_SET_SWAP_AREA:
361                 if (swsusp_swap_in_use()) {
362                         error = -EPERM;
363                 } else {
364                         struct resume_swap_area swap_area;
365                         dev_t swdev;
366
367                         error = copy_from_user(&swap_area, (void __user *)arg,
368                                         sizeof(struct resume_swap_area));
369                         if (error) {
370                                 error = -EFAULT;
371                                 break;
372                         }
373
374                         /*
375                          * User space encodes device types as two-byte values,
376                          * so we need to recode them
377                          */
378                         swdev = new_decode_dev(swap_area.dev);
379                         if (swdev) {
380                                 offset = swap_area.offset;
381                                 data->swap = swap_type_of(swdev, offset, NULL);
382                                 if (data->swap < 0)
383                                         error = -ENODEV;
384                         } else {
385                                 data->swap = -1;
386                                 error = -EINVAL;
387                         }
388                 }
389                 break;
390
391         default:
392                 error = -ENOTTY;
393
394         }
395
396         unlock_device_hotplug();
397         mutex_unlock(&system_transition_mutex);
398
399         return error;
400 }
401
402 #ifdef CONFIG_COMPAT
403
404 struct compat_resume_swap_area {
405         compat_loff_t offset;
406         u32 dev;
407 } __packed;
408
409 static long
410 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
411 {
412         BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
413
414         switch (cmd) {
415         case SNAPSHOT_GET_IMAGE_SIZE:
416         case SNAPSHOT_AVAIL_SWAP_SIZE:
417         case SNAPSHOT_ALLOC_SWAP_PAGE: {
418                 compat_loff_t __user *uoffset = compat_ptr(arg);
419                 loff_t offset;
420                 mm_segment_t old_fs;
421                 int err;
422
423                 old_fs = get_fs();
424                 set_fs(KERNEL_DS);
425                 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
426                 set_fs(old_fs);
427                 if (!err && put_user(offset, uoffset))
428                         err = -EFAULT;
429                 return err;
430         }
431
432         case SNAPSHOT_CREATE_IMAGE:
433                 return snapshot_ioctl(file, cmd,
434                                       (unsigned long) compat_ptr(arg));
435
436         case SNAPSHOT_SET_SWAP_AREA: {
437                 struct compat_resume_swap_area __user *u_swap_area =
438                         compat_ptr(arg);
439                 struct resume_swap_area swap_area;
440                 mm_segment_t old_fs;
441                 int err;
442
443                 err = get_user(swap_area.offset, &u_swap_area->offset);
444                 err |= get_user(swap_area.dev, &u_swap_area->dev);
445                 if (err)
446                         return -EFAULT;
447                 old_fs = get_fs();
448                 set_fs(KERNEL_DS);
449                 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
450                                      (unsigned long) &swap_area);
451                 set_fs(old_fs);
452                 return err;
453         }
454
455         default:
456                 return snapshot_ioctl(file, cmd, arg);
457         }
458 }
459
460 #endif /* CONFIG_COMPAT */
461
462 static const struct file_operations snapshot_fops = {
463         .open = snapshot_open,
464         .release = snapshot_release,
465         .read = snapshot_read,
466         .write = snapshot_write,
467         .llseek = no_llseek,
468         .unlocked_ioctl = snapshot_ioctl,
469 #ifdef CONFIG_COMPAT
470         .compat_ioctl = snapshot_compat_ioctl,
471 #endif
472 };
473
474 static struct miscdevice snapshot_device = {
475         .minor = SNAPSHOT_MINOR,
476         .name = "snapshot",
477         .fops = &snapshot_fops,
478 };
479
480 static int __init snapshot_device_init(void)
481 {
482         return misc_register(&snapshot_device);
483 };
484
485 device_initcall(snapshot_device_init);