swsusp: Fix userland interface
[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         int mode;
37         char frozen;
38         char ready;
39         char platform_suspend;
40 } snapshot_state;
41
42 atomic_t snapshot_device_available = ATOMIC_INIT(1);
43
44 static int snapshot_open(struct inode *inode, struct file *filp)
45 {
46         struct snapshot_data *data;
47
48         if (!atomic_add_unless(&snapshot_device_available, -1, 0))
49                 return -EBUSY;
50
51         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
52                 atomic_inc(&snapshot_device_available);
53                 return -ENOSYS;
54         }
55         if(create_basic_memory_bitmaps()) {
56                 atomic_inc(&snapshot_device_available);
57                 return -ENOMEM;
58         }
59         nonseekable_open(inode, filp);
60         data = &snapshot_state;
61         filp->private_data = data;
62         memset(&data->handle, 0, sizeof(struct snapshot_handle));
63         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
64                 data->swap = swsusp_resume_device ?
65                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
66                 data->mode = O_RDONLY;
67         } else {
68                 data->swap = -1;
69                 data->mode = O_WRONLY;
70         }
71         data->frozen = 0;
72         data->ready = 0;
73         data->platform_suspend = 0;
74
75         return 0;
76 }
77
78 static int snapshot_release(struct inode *inode, struct file *filp)
79 {
80         struct snapshot_data *data;
81
82         swsusp_free();
83         free_basic_memory_bitmaps();
84         data = filp->private_data;
85         free_all_swap_pages(data->swap);
86         if (data->frozen) {
87                 mutex_lock(&pm_mutex);
88                 thaw_processes();
89                 mutex_unlock(&pm_mutex);
90         }
91         atomic_inc(&snapshot_device_available);
92         return 0;
93 }
94
95 static ssize_t snapshot_read(struct file *filp, char __user *buf,
96                              size_t count, loff_t *offp)
97 {
98         struct snapshot_data *data;
99         ssize_t res;
100
101         data = filp->private_data;
102         if (!data->ready)
103                 return -ENODATA;
104         res = snapshot_read_next(&data->handle, count);
105         if (res > 0) {
106                 if (copy_to_user(buf, data_of(data->handle), res))
107                         res = -EFAULT;
108                 else
109                         *offp = data->handle.offset;
110         }
111         return res;
112 }
113
114 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
115                               size_t count, loff_t *offp)
116 {
117         struct snapshot_data *data;
118         ssize_t res;
119
120         data = filp->private_data;
121         res = snapshot_write_next(&data->handle, count);
122         if (res > 0) {
123                 if (copy_from_user(data_of(data->handle), buf, res))
124                         res = -EFAULT;
125                 else
126                         *offp = data->handle.offset;
127         }
128         return res;
129 }
130
131 static inline int platform_prepare(void)
132 {
133         int error = 0;
134
135         if (hibernation_ops)
136                 error = hibernation_ops->prepare();
137
138         return error;
139 }
140
141 static inline void platform_finish(void)
142 {
143         if (hibernation_ops)
144                 hibernation_ops->finish();
145 }
146
147 static inline int snapshot_suspend(int platform_suspend)
148 {
149         int error;
150
151         mutex_lock(&pm_mutex);
152         /* Free memory before shutting down devices. */
153         error = swsusp_shrink_memory();
154         if (error)
155                 goto Finish;
156
157         if (platform_suspend) {
158                 error = platform_prepare();
159                 if (error)
160                         goto Finish;
161         }
162         suspend_console();
163         error = device_suspend(PMSG_FREEZE);
164         if (error)
165                 goto Resume_devices;
166
167         error = disable_nonboot_cpus();
168         if (!error) {
169                 in_suspend = 1;
170                 error = swsusp_suspend();
171         }
172         enable_nonboot_cpus();
173  Resume_devices:
174         if (platform_suspend)
175                 platform_finish();
176
177         device_resume();
178         resume_console();
179  Finish:
180         mutex_unlock(&pm_mutex);
181         return error;
182 }
183
184 static inline int snapshot_restore(int platform_suspend)
185 {
186         int error;
187
188         mutex_lock(&pm_mutex);
189         pm_prepare_console();
190         if (platform_suspend) {
191                 error = platform_prepare();
192                 if (error)
193                         goto Finish;
194         }
195         suspend_console();
196         error = device_suspend(PMSG_PRETHAW);
197         if (error)
198                 goto Resume_devices;
199
200         error = disable_nonboot_cpus();
201         if (!error)
202                 error = swsusp_resume();
203
204         enable_nonboot_cpus();
205  Resume_devices:
206         if (platform_suspend)
207                 platform_finish();
208
209         device_resume();
210         resume_console();
211  Finish:
212         pm_restore_console();
213         mutex_unlock(&pm_mutex);
214         return error;
215 }
216
217 static int snapshot_ioctl(struct inode *inode, struct file *filp,
218                           unsigned int cmd, unsigned long arg)
219 {
220         int error = 0;
221         struct snapshot_data *data;
222         loff_t avail;
223         sector_t offset;
224
225         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
226                 return -ENOTTY;
227         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
228                 return -ENOTTY;
229         if (!capable(CAP_SYS_ADMIN))
230                 return -EPERM;
231
232         data = filp->private_data;
233
234         switch (cmd) {
235
236         case SNAPSHOT_FREEZE:
237                 if (data->frozen)
238                         break;
239                 mutex_lock(&pm_mutex);
240                 if (freeze_processes()) {
241                         thaw_processes();
242                         error = -EBUSY;
243                 }
244                 mutex_unlock(&pm_mutex);
245                 if (!error)
246                         data->frozen = 1;
247                 break;
248
249         case SNAPSHOT_UNFREEZE:
250                 if (!data->frozen || data->ready)
251                         break;
252                 mutex_lock(&pm_mutex);
253                 thaw_processes();
254                 mutex_unlock(&pm_mutex);
255                 data->frozen = 0;
256                 break;
257
258         case SNAPSHOT_ATOMIC_SNAPSHOT:
259                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
260                         error = -EPERM;
261                         break;
262                 }
263                 error = snapshot_suspend(data->platform_suspend);
264                 if (!error)
265                         error = put_user(in_suspend, (unsigned int __user *)arg);
266                 if (!error)
267                         data->ready = 1;
268                 break;
269
270         case SNAPSHOT_ATOMIC_RESTORE:
271                 snapshot_write_finalize(&data->handle);
272                 if (data->mode != O_WRONLY || !data->frozen ||
273                     !snapshot_image_loaded(&data->handle)) {
274                         error = -EPERM;
275                         break;
276                 }
277                 error = snapshot_restore(data->platform_suspend);
278                 break;
279
280         case SNAPSHOT_FREE:
281                 swsusp_free();
282                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
283                 data->ready = 0;
284                 break;
285
286         case SNAPSHOT_SET_IMAGE_SIZE:
287                 image_size = arg;
288                 break;
289
290         case SNAPSHOT_AVAIL_SWAP:
291                 avail = count_swap_pages(data->swap, 1);
292                 avail <<= PAGE_SHIFT;
293                 error = put_user(avail, (loff_t __user *)arg);
294                 break;
295
296         case SNAPSHOT_GET_SWAP_PAGE:
297                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
298                         error = -ENODEV;
299                         break;
300                 }
301                 offset = alloc_swapdev_block(data->swap);
302                 if (offset) {
303                         offset <<= PAGE_SHIFT;
304                         error = put_user(offset, (sector_t __user *)arg);
305                 } else {
306                         error = -ENOSPC;
307                 }
308                 break;
309
310         case SNAPSHOT_FREE_SWAP_PAGES:
311                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
312                         error = -ENODEV;
313                         break;
314                 }
315                 free_all_swap_pages(data->swap);
316                 break;
317
318         case SNAPSHOT_SET_SWAP_FILE:
319                 if (!swsusp_swap_in_use()) {
320                         /*
321                          * User space encodes device types as two-byte values,
322                          * so we need to recode them
323                          */
324                         if (old_decode_dev(arg)) {
325                                 data->swap = swap_type_of(old_decode_dev(arg),
326                                                         0, NULL);
327                                 if (data->swap < 0)
328                                         error = -ENODEV;
329                         } else {
330                                 data->swap = -1;
331                                 error = -EINVAL;
332                         }
333                 } else {
334                         error = -EPERM;
335                 }
336                 break;
337
338         case SNAPSHOT_S2RAM:
339                 if (!pm_ops) {
340                         error = -ENOSYS;
341                         break;
342                 }
343
344                 if (!data->frozen) {
345                         error = -EPERM;
346                         break;
347                 }
348
349                 if (!mutex_trylock(&pm_mutex)) {
350                         error = -EBUSY;
351                         break;
352                 }
353
354                 if (pm_ops->prepare) {
355                         error = pm_ops->prepare(PM_SUSPEND_MEM);
356                         if (error)
357                                 goto OutS3;
358                 }
359
360                 /* Put devices to sleep */
361                 suspend_console();
362                 error = device_suspend(PMSG_SUSPEND);
363                 if (error) {
364                         printk(KERN_ERR "Failed to suspend some devices.\n");
365                 } else {
366                         error = disable_nonboot_cpus();
367                         if (!error) {
368                                 /* Enter S3, system is already frozen */
369                                 suspend_enter(PM_SUSPEND_MEM);
370                                 enable_nonboot_cpus();
371                         }
372                         /* Wake up devices */
373                         device_resume();
374                 }
375                 resume_console();
376                 if (pm_ops->finish)
377                         pm_ops->finish(PM_SUSPEND_MEM);
378
379  OutS3:
380                 mutex_unlock(&pm_mutex);
381                 break;
382
383         case SNAPSHOT_PMOPS:
384                 error = -EINVAL;
385
386                 switch (arg) {
387
388                 case PMOPS_PREPARE:
389                         if (hibernation_ops) {
390                                 data->platform_suspend = 1;
391                                 error = 0;
392                         } else {
393                                 error = -ENOSYS;
394                         }
395                         break;
396
397                 case PMOPS_ENTER:
398                         if (data->platform_suspend) {
399                                 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
400                                 error = hibernation_ops->enter();
401                         }
402                         break;
403
404                 case PMOPS_FINISH:
405                         if (data->platform_suspend)
406                                 error = 0;
407
408                         break;
409
410                 default:
411                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
412
413                 }
414                 break;
415
416         case SNAPSHOT_SET_SWAP_AREA:
417                 if (swsusp_swap_in_use()) {
418                         error = -EPERM;
419                 } else {
420                         struct resume_swap_area swap_area;
421                         dev_t swdev;
422
423                         error = copy_from_user(&swap_area, (void __user *)arg,
424                                         sizeof(struct resume_swap_area));
425                         if (error) {
426                                 error = -EFAULT;
427                                 break;
428                         }
429
430                         /*
431                          * User space encodes device types as two-byte values,
432                          * so we need to recode them
433                          */
434                         swdev = old_decode_dev(swap_area.dev);
435                         if (swdev) {
436                                 offset = swap_area.offset;
437                                 data->swap = swap_type_of(swdev, offset, NULL);
438                                 if (data->swap < 0)
439                                         error = -ENODEV;
440                         } else {
441                                 data->swap = -1;
442                                 error = -EINVAL;
443                         }
444                 }
445                 break;
446
447         default:
448                 error = -ENOTTY;
449
450         }
451
452         return error;
453 }
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         .ioctl = snapshot_ioctl,
462 };
463
464 static struct miscdevice snapshot_device = {
465         .minor = SNAPSHOT_MINOR,
466         .name = "snapshot",
467         .fops = &snapshot_fops,
468 };
469
470 static int __init snapshot_device_init(void)
471 {
472         return misc_register(&snapshot_device);
473 };
474
475 device_initcall(snapshot_device_init);