[PATCH] convert pm_sem to a mutex
[linux-2.6.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/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 } snapshot_state;
41
42 static atomic_t 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(&device_available, -1, 0))
49                 return -EBUSY;
50
51         if ((filp->f_flags & O_ACCMODE) == O_RDWR)
52                 return -ENOSYS;
53
54         nonseekable_open(inode, filp);
55         data = &snapshot_state;
56         filp->private_data = data;
57         memset(&data->handle, 0, sizeof(struct snapshot_handle));
58         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
59                 data->swap = swsusp_resume_device ?
60                                 swap_type_of(swsusp_resume_device, 0) : -1;
61                 data->mode = O_RDONLY;
62         } else {
63                 data->swap = -1;
64                 data->mode = O_WRONLY;
65         }
66         data->bitmap = NULL;
67         data->frozen = 0;
68         data->ready = 0;
69
70         return 0;
71 }
72
73 static int snapshot_release(struct inode *inode, struct file *filp)
74 {
75         struct snapshot_data *data;
76
77         swsusp_free();
78         data = filp->private_data;
79         free_all_swap_pages(data->swap, data->bitmap);
80         free_bitmap(data->bitmap);
81         if (data->frozen) {
82                 mutex_lock(&pm_mutex);
83                 thaw_processes();
84                 enable_nonboot_cpus();
85                 mutex_unlock(&pm_mutex);
86         }
87         atomic_inc(&device_available);
88         return 0;
89 }
90
91 static ssize_t snapshot_read(struct file *filp, char __user *buf,
92                              size_t count, loff_t *offp)
93 {
94         struct snapshot_data *data;
95         ssize_t res;
96
97         data = filp->private_data;
98         res = snapshot_read_next(&data->handle, count);
99         if (res > 0) {
100                 if (copy_to_user(buf, data_of(data->handle), res))
101                         res = -EFAULT;
102                 else
103                         *offp = data->handle.offset;
104         }
105         return res;
106 }
107
108 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
109                               size_t count, loff_t *offp)
110 {
111         struct snapshot_data *data;
112         ssize_t res;
113
114         data = filp->private_data;
115         res = snapshot_write_next(&data->handle, count);
116         if (res > 0) {
117                 if (copy_from_user(data_of(data->handle), buf, res))
118                         res = -EFAULT;
119                 else
120                         *offp = data->handle.offset;
121         }
122         return res;
123 }
124
125 static int snapshot_ioctl(struct inode *inode, struct file *filp,
126                           unsigned int cmd, unsigned long arg)
127 {
128         int error = 0;
129         struct snapshot_data *data;
130         loff_t avail;
131         sector_t offset;
132
133         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
134                 return -ENOTTY;
135         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
136                 return -ENOTTY;
137         if (!capable(CAP_SYS_ADMIN))
138                 return -EPERM;
139
140         data = filp->private_data;
141
142         switch (cmd) {
143
144         case SNAPSHOT_FREEZE:
145                 if (data->frozen)
146                         break;
147                 mutex_lock(&pm_mutex);
148                 error = disable_nonboot_cpus();
149                 if (!error) {
150                         error = freeze_processes();
151                         if (error) {
152                                 thaw_processes();
153                                 enable_nonboot_cpus();
154                                 error = -EBUSY;
155                         }
156                 }
157                 mutex_unlock(&pm_mutex);
158                 if (!error)
159                         data->frozen = 1;
160                 break;
161
162         case SNAPSHOT_UNFREEZE:
163                 if (!data->frozen)
164                         break;
165                 mutex_lock(&pm_mutex);
166                 thaw_processes();
167                 enable_nonboot_cpus();
168                 mutex_unlock(&pm_mutex);
169                 data->frozen = 0;
170                 break;
171
172         case SNAPSHOT_ATOMIC_SNAPSHOT:
173                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
174                         error = -EPERM;
175                         break;
176                 }
177                 mutex_lock(&pm_mutex);
178                 /* Free memory before shutting down devices. */
179                 error = swsusp_shrink_memory();
180                 if (!error) {
181                         suspend_console();
182                         error = device_suspend(PMSG_FREEZE);
183                         if (!error) {
184                                 in_suspend = 1;
185                                 error = swsusp_suspend();
186                                 device_resume();
187                         }
188                         resume_console();
189                 }
190                 mutex_unlock(&pm_mutex);
191                 if (!error)
192                         error = put_user(in_suspend, (unsigned int __user *)arg);
193                 if (!error)
194                         data->ready = 1;
195                 break;
196
197         case SNAPSHOT_ATOMIC_RESTORE:
198                 snapshot_write_finalize(&data->handle);
199                 if (data->mode != O_WRONLY || !data->frozen ||
200                     !snapshot_image_loaded(&data->handle)) {
201                         error = -EPERM;
202                         break;
203                 }
204                 mutex_lock(&pm_mutex);
205                 pm_prepare_console();
206                 suspend_console();
207                 error = device_suspend(PMSG_PRETHAW);
208                 if (!error) {
209                         error = swsusp_resume();
210                         device_resume();
211                 }
212                 resume_console();
213                 pm_restore_console();
214                 mutex_unlock(&pm_mutex);
215                 break;
216
217         case SNAPSHOT_FREE:
218                 swsusp_free();
219                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
220                 data->ready = 0;
221                 break;
222
223         case SNAPSHOT_SET_IMAGE_SIZE:
224                 image_size = arg;
225                 break;
226
227         case SNAPSHOT_AVAIL_SWAP:
228                 avail = count_swap_pages(data->swap, 1);
229                 avail <<= PAGE_SHIFT;
230                 error = put_user(avail, (loff_t __user *)arg);
231                 break;
232
233         case SNAPSHOT_GET_SWAP_PAGE:
234                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
235                         error = -ENODEV;
236                         break;
237                 }
238                 if (!data->bitmap) {
239                         data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
240                         if (!data->bitmap) {
241                                 error = -ENOMEM;
242                                 break;
243                         }
244                 }
245                 offset = alloc_swapdev_block(data->swap, data->bitmap);
246                 if (offset) {
247                         offset <<= PAGE_SHIFT;
248                         error = put_user(offset, (sector_t __user *)arg);
249                 } else {
250                         error = -ENOSPC;
251                 }
252                 break;
253
254         case SNAPSHOT_FREE_SWAP_PAGES:
255                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
256                         error = -ENODEV;
257                         break;
258                 }
259                 free_all_swap_pages(data->swap, data->bitmap);
260                 free_bitmap(data->bitmap);
261                 data->bitmap = NULL;
262                 break;
263
264         case SNAPSHOT_SET_SWAP_FILE:
265                 if (!data->bitmap) {
266                         /*
267                          * User space encodes device types as two-byte values,
268                          * so we need to recode them
269                          */
270                         if (old_decode_dev(arg)) {
271                                 data->swap = swap_type_of(old_decode_dev(arg), 0);
272                                 if (data->swap < 0)
273                                         error = -ENODEV;
274                         } else {
275                                 data->swap = -1;
276                                 error = -EINVAL;
277                         }
278                 } else {
279                         error = -EPERM;
280                 }
281                 break;
282
283         case SNAPSHOT_S2RAM:
284                 if (!data->frozen) {
285                         error = -EPERM;
286                         break;
287                 }
288
289                 if (!mutex_trylock(&pm_mutex)) {
290                         error = -EBUSY;
291                         break;
292                 }
293
294                 if (pm_ops->prepare) {
295                         error = pm_ops->prepare(PM_SUSPEND_MEM);
296                         if (error)
297                                 goto OutS3;
298                 }
299
300                 /* Put devices to sleep */
301                 suspend_console();
302                 error = device_suspend(PMSG_SUSPEND);
303                 if (error) {
304                         printk(KERN_ERR "Failed to suspend some devices.\n");
305                 } else {
306                         /* Enter S3, system is already frozen */
307                         suspend_enter(PM_SUSPEND_MEM);
308
309                         /* Wake up devices */
310                         device_resume();
311                 }
312                 resume_console();
313                 if (pm_ops->finish)
314                         pm_ops->finish(PM_SUSPEND_MEM);
315
316 OutS3:
317                 mutex_unlock(&pm_mutex);
318                 break;
319
320         case SNAPSHOT_PMOPS:
321                 switch (arg) {
322
323                 case PMOPS_PREPARE:
324                         if (pm_ops->prepare) {
325                                 error = pm_ops->prepare(PM_SUSPEND_DISK);
326                         }
327                         break;
328
329                 case PMOPS_ENTER:
330                         kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
331                         error = pm_ops->enter(PM_SUSPEND_DISK);
332                         break;
333
334                 case PMOPS_FINISH:
335                         if (pm_ops && pm_ops->finish) {
336                                 pm_ops->finish(PM_SUSPEND_DISK);
337                         }
338                         break;
339
340                 default:
341                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
342                         error = -EINVAL;
343
344                 }
345                 break;
346
347         case SNAPSHOT_SET_SWAP_AREA:
348                 if (data->bitmap) {
349                         error = -EPERM;
350                 } else {
351                         struct resume_swap_area swap_area;
352                         dev_t swdev;
353
354                         error = copy_from_user(&swap_area, (void __user *)arg,
355                                         sizeof(struct resume_swap_area));
356                         if (error) {
357                                 error = -EFAULT;
358                                 break;
359                         }
360
361                         /*
362                          * User space encodes device types as two-byte values,
363                          * so we need to recode them
364                          */
365                         swdev = old_decode_dev(swap_area.dev);
366                         if (swdev) {
367                                 offset = swap_area.offset;
368                                 data->swap = swap_type_of(swdev, offset);
369                                 if (data->swap < 0)
370                                         error = -ENODEV;
371                         } else {
372                                 data->swap = -1;
373                                 error = -EINVAL;
374                         }
375                 }
376                 break;
377
378         default:
379                 error = -ENOTTY;
380
381         }
382
383         return error;
384 }
385
386 static struct file_operations snapshot_fops = {
387         .open = snapshot_open,
388         .release = snapshot_release,
389         .read = snapshot_read,
390         .write = snapshot_write,
391         .llseek = no_llseek,
392         .ioctl = snapshot_ioctl,
393 };
394
395 static struct miscdevice snapshot_device = {
396         .minor = SNAPSHOT_MINOR,
397         .name = "snapshot",
398         .fops = &snapshot_fops,
399 };
400
401 static int __init snapshot_device_init(void)
402 {
403         return misc_register(&snapshot_device);
404 };
405
406 device_initcall(snapshot_device_init);