Merge branch 'upstream-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/linvil...
[linux-2.6] / 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/console.h>
24 #include <linux/cpu.h>
25 #include <linux/freezer.h>
26
27 #include <asm/uaccess.h>
28
29 #include "power.h"
30
31 #define SNAPSHOT_MINOR  231
32
33 static struct snapshot_data {
34         struct snapshot_handle handle;
35         int swap;
36         struct bitmap_page *bitmap;
37         int mode;
38         char frozen;
39         char ready;
40         char platform_suspend;
41 } snapshot_state;
42
43 static atomic_t device_available = ATOMIC_INIT(1);
44
45 static int snapshot_open(struct inode *inode, struct file *filp)
46 {
47         struct snapshot_data *data;
48
49         if (!atomic_add_unless(&device_available, -1, 0))
50                 return -EBUSY;
51
52         if ((filp->f_flags & O_ACCMODE) == O_RDWR)
53                 return -ENOSYS;
54
55         nonseekable_open(inode, filp);
56         data = &snapshot_state;
57         filp->private_data = data;
58         memset(&data->handle, 0, sizeof(struct snapshot_handle));
59         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
60                 data->swap = swsusp_resume_device ?
61                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
62                 data->mode = O_RDONLY;
63         } else {
64                 data->swap = -1;
65                 data->mode = O_WRONLY;
66         }
67         data->bitmap = NULL;
68         data->frozen = 0;
69         data->ready = 0;
70         data->platform_suspend = 0;
71
72         return 0;
73 }
74
75 static int snapshot_release(struct inode *inode, struct file *filp)
76 {
77         struct snapshot_data *data;
78
79         swsusp_free();
80         data = filp->private_data;
81         free_all_swap_pages(data->swap, data->bitmap);
82         free_bitmap(data->bitmap);
83         if (data->frozen) {
84                 mutex_lock(&pm_mutex);
85                 thaw_processes();
86                 enable_nonboot_cpus();
87                 mutex_unlock(&pm_mutex);
88         }
89         atomic_inc(&device_available);
90         return 0;
91 }
92
93 static ssize_t snapshot_read(struct file *filp, char __user *buf,
94                              size_t count, loff_t *offp)
95 {
96         struct snapshot_data *data;
97         ssize_t res;
98
99         data = filp->private_data;
100         res = snapshot_read_next(&data->handle, count);
101         if (res > 0) {
102                 if (copy_to_user(buf, data_of(data->handle), res))
103                         res = -EFAULT;
104                 else
105                         *offp = data->handle.offset;
106         }
107         return res;
108 }
109
110 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
111                               size_t count, loff_t *offp)
112 {
113         struct snapshot_data *data;
114         ssize_t res;
115
116         data = filp->private_data;
117         res = snapshot_write_next(&data->handle, count);
118         if (res > 0) {
119                 if (copy_from_user(data_of(data->handle), buf, res))
120                         res = -EFAULT;
121                 else
122                         *offp = data->handle.offset;
123         }
124         return res;
125 }
126
127 static inline int platform_prepare(void)
128 {
129         int error = 0;
130
131         if (pm_ops && pm_ops->prepare)
132                 error = pm_ops->prepare(PM_SUSPEND_DISK);
133
134         return error;
135 }
136
137 static inline void platform_finish(void)
138 {
139         if (pm_ops && pm_ops->finish)
140                 pm_ops->finish(PM_SUSPEND_DISK);
141 }
142
143 static inline int snapshot_suspend(int platform_suspend)
144 {
145         int error;
146
147         mutex_lock(&pm_mutex);
148         /* Free memory before shutting down devices. */
149         error = swsusp_shrink_memory();
150         if (error)
151                 goto Finish;
152
153         if (platform_suspend) {
154                 error = platform_prepare();
155                 if (error)
156                         goto Finish;
157         }
158         suspend_console();
159         error = device_suspend(PMSG_FREEZE);
160         if (error)
161                 goto Resume_devices;
162
163         error = disable_nonboot_cpus();
164         if (!error) {
165                 in_suspend = 1;
166                 error = swsusp_suspend();
167         }
168         enable_nonboot_cpus();
169  Resume_devices:
170         if (platform_suspend)
171                 platform_finish();
172
173         device_resume();
174         resume_console();
175  Finish:
176         mutex_unlock(&pm_mutex);
177         return error;
178 }
179
180 static inline int snapshot_restore(int platform_suspend)
181 {
182         int error;
183
184         mutex_lock(&pm_mutex);
185         pm_prepare_console();
186         if (platform_suspend) {
187                 error = platform_prepare();
188                 if (error)
189                         goto Finish;
190         }
191         suspend_console();
192         error = device_suspend(PMSG_PRETHAW);
193         if (error)
194                 goto Resume_devices;
195
196         error = disable_nonboot_cpus();
197         if (!error)
198                 error = swsusp_resume();
199
200         enable_nonboot_cpus();
201  Resume_devices:
202         if (platform_suspend)
203                 platform_finish();
204
205         device_resume();
206         resume_console();
207  Finish:
208         pm_restore_console();
209         mutex_unlock(&pm_mutex);
210         return error;
211 }
212
213 static int snapshot_ioctl(struct inode *inode, struct file *filp,
214                           unsigned int cmd, unsigned long arg)
215 {
216         int error = 0;
217         struct snapshot_data *data;
218         loff_t avail;
219         sector_t offset;
220
221         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
222                 return -ENOTTY;
223         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
224                 return -ENOTTY;
225         if (!capable(CAP_SYS_ADMIN))
226                 return -EPERM;
227
228         data = filp->private_data;
229
230         switch (cmd) {
231
232         case SNAPSHOT_FREEZE:
233                 if (data->frozen)
234                         break;
235                 mutex_lock(&pm_mutex);
236                 if (freeze_processes()) {
237                         thaw_processes();
238                         error = -EBUSY;
239                 }
240                 mutex_unlock(&pm_mutex);
241                 if (!error)
242                         data->frozen = 1;
243                 break;
244
245         case SNAPSHOT_UNFREEZE:
246                 if (!data->frozen)
247                         break;
248                 mutex_lock(&pm_mutex);
249                 thaw_processes();
250                 mutex_unlock(&pm_mutex);
251                 data->frozen = 0;
252                 break;
253
254         case SNAPSHOT_ATOMIC_SNAPSHOT:
255                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
256                         error = -EPERM;
257                         break;
258                 }
259                 error = snapshot_suspend(data->platform_suspend);
260                 if (!error)
261                         error = put_user(in_suspend, (unsigned int __user *)arg);
262                 if (!error)
263                         data->ready = 1;
264                 break;
265
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;
272                 }
273                 error = snapshot_restore(data->platform_suspend);
274                 break;
275
276         case SNAPSHOT_FREE:
277                 swsusp_free();
278                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
279                 data->ready = 0;
280                 break;
281
282         case SNAPSHOT_SET_IMAGE_SIZE:
283                 image_size = arg;
284                 break;
285
286         case SNAPSHOT_AVAIL_SWAP:
287                 avail = count_swap_pages(data->swap, 1);
288                 avail <<= PAGE_SHIFT;
289                 error = put_user(avail, (loff_t __user *)arg);
290                 break;
291
292         case SNAPSHOT_GET_SWAP_PAGE:
293                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
294                         error = -ENODEV;
295                         break;
296                 }
297                 if (!data->bitmap) {
298                         data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
299                         if (!data->bitmap) {
300                                 error = -ENOMEM;
301                                 break;
302                         }
303                 }
304                 offset = alloc_swapdev_block(data->swap, data->bitmap);
305                 if (offset) {
306                         offset <<= PAGE_SHIFT;
307                         error = put_user(offset, (sector_t __user *)arg);
308                 } else {
309                         error = -ENOSPC;
310                 }
311                 break;
312
313         case SNAPSHOT_FREE_SWAP_PAGES:
314                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
315                         error = -ENODEV;
316                         break;
317                 }
318                 free_all_swap_pages(data->swap, data->bitmap);
319                 free_bitmap(data->bitmap);
320                 data->bitmap = NULL;
321                 break;
322
323         case SNAPSHOT_SET_SWAP_FILE:
324                 if (!data->bitmap) {
325                         /*
326                          * User space encodes device types as two-byte values,
327                          * so we need to recode them
328                          */
329                         if (old_decode_dev(arg)) {
330                                 data->swap = swap_type_of(old_decode_dev(arg),
331                                                         0, NULL);
332                                 if (data->swap < 0)
333                                         error = -ENODEV;
334                         } else {
335                                 data->swap = -1;
336                                 error = -EINVAL;
337                         }
338                 } else {
339                         error = -EPERM;
340                 }
341                 break;
342
343         case SNAPSHOT_S2RAM:
344                 if (!pm_ops) {
345                         error = -ENOSYS;
346                         break;
347                 }
348
349                 if (!data->frozen) {
350                         error = -EPERM;
351                         break;
352                 }
353
354                 if (!mutex_trylock(&pm_mutex)) {
355                         error = -EBUSY;
356                         break;
357                 }
358
359                 if (pm_ops->prepare) {
360                         error = pm_ops->prepare(PM_SUSPEND_MEM);
361                         if (error)
362                                 goto OutS3;
363                 }
364
365                 /* Put devices to sleep */
366                 suspend_console();
367                 error = device_suspend(PMSG_SUSPEND);
368                 if (error) {
369                         printk(KERN_ERR "Failed to suspend some devices.\n");
370                 } else {
371                         error = disable_nonboot_cpus();
372                         if (!error) {
373                                 /* Enter S3, system is already frozen */
374                                 suspend_enter(PM_SUSPEND_MEM);
375                                 enable_nonboot_cpus();
376                         }
377                         /* Wake up devices */
378                         device_resume();
379                 }
380                 resume_console();
381                 if (pm_ops->finish)
382                         pm_ops->finish(PM_SUSPEND_MEM);
383
384  OutS3:
385                 mutex_unlock(&pm_mutex);
386                 break;
387
388         case SNAPSHOT_PMOPS:
389                 error = -EINVAL;
390
391                 switch (arg) {
392
393                 case PMOPS_PREPARE:
394                         if (pm_ops && pm_ops->enter) {
395                                 data->platform_suspend = 1;
396                                 error = 0;
397                         } else {
398                                 error = -ENOSYS;
399                         }
400                         break;
401
402                 case PMOPS_ENTER:
403                         if (data->platform_suspend) {
404                                 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
405                                 error = pm_ops->enter(PM_SUSPEND_DISK);
406                                 error = 0;
407                         }
408                         break;
409
410                 case PMOPS_FINISH:
411                         if (data->platform_suspend)
412                                 error = 0;
413
414                         break;
415
416                 default:
417                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
418
419                 }
420                 break;
421
422         case SNAPSHOT_SET_SWAP_AREA:
423                 if (data->bitmap) {
424                         error = -EPERM;
425                 } else {
426                         struct resume_swap_area swap_area;
427                         dev_t swdev;
428
429                         error = copy_from_user(&swap_area, (void __user *)arg,
430                                         sizeof(struct resume_swap_area));
431                         if (error) {
432                                 error = -EFAULT;
433                                 break;
434                         }
435
436                         /*
437                          * User space encodes device types as two-byte values,
438                          * so we need to recode them
439                          */
440                         swdev = old_decode_dev(swap_area.dev);
441                         if (swdev) {
442                                 offset = swap_area.offset;
443                                 data->swap = swap_type_of(swdev, offset, NULL);
444                                 if (data->swap < 0)
445                                         error = -ENODEV;
446                         } else {
447                                 data->swap = -1;
448                                 error = -EINVAL;
449                         }
450                 }
451                 break;
452
453         default:
454                 error = -ENOTTY;
455
456         }
457
458         return error;
459 }
460
461 static const struct file_operations snapshot_fops = {
462         .open = snapshot_open,
463         .release = snapshot_release,
464         .read = snapshot_read,
465         .write = snapshot_write,
466         .llseek = no_llseek,
467         .ioctl = snapshot_ioctl,
468 };
469
470 static struct miscdevice snapshot_device = {
471         .minor = SNAPSHOT_MINOR,
472         .name = "snapshot",
473         .fops = &snapshot_fops,
474 };
475
476 static int __init snapshot_device_init(void)
477 {
478         return misc_register(&snapshot_device);
479 };
480
481 device_initcall(snapshot_device_init);