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TOMOYO Linux Cross Reference
Linux/kernel/power/user.c

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  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 <asm/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         char frozen;
 40         char ready;
 41         char platform_support;
 42 } snapshot_state;
 43 
 44 atomic_t snapshot_device_available = ATOMIC_INIT(1);
 45 
 46 static int snapshot_open(struct inode *inode, struct file *filp)
 47 {
 48         struct snapshot_data *data;
 49         int error;
 50 
 51         lock_system_sleep();
 52 
 53         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 54                 error = -EBUSY;
 55                 goto Unlock;
 56         }
 57 
 58         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
 59                 atomic_inc(&snapshot_device_available);
 60                 error = -ENOSYS;
 61                 goto Unlock;
 62         }
 63         if(create_basic_memory_bitmaps()) {
 64                 atomic_inc(&snapshot_device_available);
 65                 error = -ENOMEM;
 66                 goto Unlock;
 67         }
 68         nonseekable_open(inode, filp);
 69         data = &snapshot_state;
 70         filp->private_data = data;
 71         memset(&data->handle, 0, sizeof(struct snapshot_handle));
 72         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
 73                 /* Hibernating.  The image device should be accessible. */
 74                 data->swap = swsusp_resume_device ?
 75                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
 76                 data->mode = O_RDONLY;
 77                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 78                 if (error)
 79                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 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);
 90                 if (error)
 91                         pm_notifier_call_chain(PM_POST_RESTORE);
 92         }
 93         if (error) {
 94                 free_basic_memory_bitmaps();
 95                 atomic_inc(&snapshot_device_available);
 96         }
 97         data->frozen = 0;
 98         data->ready = 0;
 99         data->platform_support = 0;
100 
101  Unlock:
102         unlock_system_sleep();
103 
104         return error;
105 }
106 
107 static int snapshot_release(struct inode *inode, struct file *filp)
108 {
109         struct snapshot_data *data;
110 
111         lock_system_sleep();
112 
113         swsusp_free();
114         free_basic_memory_bitmaps();
115         data = filp->private_data;
116         free_all_swap_pages(data->swap);
117         if (data->frozen) {
118                 pm_restore_gfp_mask();
119                 thaw_processes();
120         }
121         pm_notifier_call_chain(data->mode == O_RDONLY ?
122                         PM_POST_HIBERNATION : PM_POST_RESTORE);
123         atomic_inc(&snapshot_device_available);
124 
125         unlock_system_sleep();
126 
127         return 0;
128 }
129 
130 static ssize_t snapshot_read(struct file *filp, char __user *buf,
131                              size_t count, loff_t *offp)
132 {
133         struct snapshot_data *data;
134         ssize_t res;
135         loff_t pg_offp = *offp & ~PAGE_MASK;
136 
137         lock_system_sleep();
138 
139         data = filp->private_data;
140         if (!data->ready) {
141                 res = -ENODATA;
142                 goto Unlock;
143         }
144         if (!pg_offp) { /* on page boundary? */
145                 res = snapshot_read_next(&data->handle);
146                 if (res <= 0)
147                         goto Unlock;
148         } else {
149                 res = PAGE_SIZE - pg_offp;
150         }
151 
152         res = simple_read_from_buffer(buf, count, &pg_offp,
153                         data_of(data->handle), res);
154         if (res > 0)
155                 *offp += res;
156 
157  Unlock:
158         unlock_system_sleep();
159 
160         return res;
161 }
162 
163 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
164                               size_t count, loff_t *offp)
165 {
166         struct snapshot_data *data;
167         ssize_t res;
168         loff_t pg_offp = *offp & ~PAGE_MASK;
169 
170         lock_system_sleep();
171 
172         data = filp->private_data;
173 
174         if (!pg_offp) {
175                 res = snapshot_write_next(&data->handle);
176                 if (res <= 0)
177                         goto unlock;
178         } else {
179                 res = PAGE_SIZE - pg_offp;
180         }
181 
182         res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
183                         buf, count);
184         if (res > 0)
185                 *offp += res;
186 unlock:
187         unlock_system_sleep();
188 
189         return res;
190 }
191 
192 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
193                                                         unsigned long arg)
194 {
195         int error = 0;
196         struct snapshot_data *data;
197         loff_t size;
198         sector_t offset;
199 
200         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
201                 return -ENOTTY;
202         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
203                 return -ENOTTY;
204         if (!capable(CAP_SYS_ADMIN))
205                 return -EPERM;
206 
207         if (!mutex_trylock(&pm_mutex))
208                 return -EBUSY;
209 
210         data = filp->private_data;
211 
212         switch (cmd) {
213 
214         case SNAPSHOT_FREEZE:
215                 if (data->frozen)
216                         break;
217 
218                 printk("Syncing filesystems ... ");
219                 sys_sync();
220                 printk("done.\n");
221 
222                 error = freeze_processes();
223                 if (!error)
224                         data->frozen = 1;
225                 break;
226 
227         case SNAPSHOT_UNFREEZE:
228                 if (!data->frozen || data->ready)
229                         break;
230                 pm_restore_gfp_mask();
231                 thaw_processes();
232                 data->frozen = 0;
233                 break;
234 
235         case SNAPSHOT_CREATE_IMAGE:
236                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
237                         error = -EPERM;
238                         break;
239                 }
240                 pm_restore_gfp_mask();
241                 error = hibernation_snapshot(data->platform_support);
242                 if (!error) {
243                         error = put_user(in_suspend, (int __user *)arg);
244                         data->ready = !freezer_test_done && !error;
245                         freezer_test_done = false;
246                 }
247                 break;
248 
249         case SNAPSHOT_ATOMIC_RESTORE:
250                 snapshot_write_finalize(&data->handle);
251                 if (data->mode != O_WRONLY || !data->frozen ||
252                     !snapshot_image_loaded(&data->handle)) {
253                         error = -EPERM;
254                         break;
255                 }
256                 error = hibernation_restore(data->platform_support);
257                 break;
258 
259         case SNAPSHOT_FREE:
260                 swsusp_free();
261                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
262                 data->ready = 0;
263                 /*
264                  * It is necessary to thaw kernel threads here, because
265                  * SNAPSHOT_CREATE_IMAGE may be invoked directly after
266                  * SNAPSHOT_FREE.  In that case, if kernel threads were not
267                  * thawed, the preallocation of memory carried out by
268                  * hibernation_snapshot() might run into problems (i.e. it
269                  * might fail or even deadlock).
270                  */
271                 thaw_kernel_threads();
272                 break;
273 
274         case SNAPSHOT_PREF_IMAGE_SIZE:
275                 image_size = arg;
276                 break;
277 
278         case SNAPSHOT_GET_IMAGE_SIZE:
279                 if (!data->ready) {
280                         error = -ENODATA;
281                         break;
282                 }
283                 size = snapshot_get_image_size();
284                 size <<= PAGE_SHIFT;
285                 error = put_user(size, (loff_t __user *)arg);
286                 break;
287 
288         case SNAPSHOT_AVAIL_SWAP_SIZE:
289                 size = count_swap_pages(data->swap, 1);
290                 size <<= PAGE_SHIFT;
291                 error = put_user(size, (loff_t __user *)arg);
292                 break;
293 
294         case SNAPSHOT_ALLOC_SWAP_PAGE:
295                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
296                         error = -ENODEV;
297                         break;
298                 }
299                 offset = alloc_swapdev_block(data->swap);
300                 if (offset) {
301                         offset <<= PAGE_SHIFT;
302                         error = put_user(offset, (loff_t __user *)arg);
303                 } else {
304                         error = -ENOSPC;
305                 }
306                 break;
307 
308         case SNAPSHOT_FREE_SWAP_PAGES:
309                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
310                         error = -ENODEV;
311                         break;
312                 }
313                 free_all_swap_pages(data->swap);
314                 break;
315 
316         case SNAPSHOT_S2RAM:
317                 if (!data->frozen) {
318                         error = -EPERM;
319                         break;
320                 }
321                 /*
322                  * Tasks are frozen and the notifiers have been called with
323                  * PM_HIBERNATION_PREPARE
324                  */
325                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
326                 data->ready = 0;
327                 break;
328 
329         case SNAPSHOT_PLATFORM_SUPPORT:
330                 data->platform_support = !!arg;
331                 break;
332 
333         case SNAPSHOT_POWER_OFF:
334                 if (data->platform_support)
335                         error = hibernation_platform_enter();
336                 break;
337 
338         case SNAPSHOT_SET_SWAP_AREA:
339                 if (swsusp_swap_in_use()) {
340                         error = -EPERM;
341                 } else {
342                         struct resume_swap_area swap_area;
343                         dev_t swdev;
344 
345                         error = copy_from_user(&swap_area, (void __user *)arg,
346                                         sizeof(struct resume_swap_area));
347                         if (error) {
348                                 error = -EFAULT;
349                                 break;
350                         }
351 
352                         /*
353                          * User space encodes device types as two-byte values,
354                          * so we need to recode them
355                          */
356                         swdev = new_decode_dev(swap_area.dev);
357                         if (swdev) {
358                                 offset = swap_area.offset;
359                                 data->swap = swap_type_of(swdev, offset, NULL);
360                                 if (data->swap < 0)
361                                         error = -ENODEV;
362                         } else {
363                                 data->swap = -1;
364                                 error = -EINVAL;
365                         }
366                 }
367                 break;
368 
369         default:
370                 error = -ENOTTY;
371 
372         }
373 
374         mutex_unlock(&pm_mutex);
375 
376         return error;
377 }
378 
379 #ifdef CONFIG_COMPAT
380 
381 struct compat_resume_swap_area {
382         compat_loff_t offset;
383         u32 dev;
384 } __packed;
385 
386 static long
387 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
388 {
389         BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
390 
391         switch (cmd) {
392         case SNAPSHOT_GET_IMAGE_SIZE:
393         case SNAPSHOT_AVAIL_SWAP_SIZE:
394         case SNAPSHOT_ALLOC_SWAP_PAGE: {
395                 compat_loff_t __user *uoffset = compat_ptr(arg);
396                 loff_t offset;
397                 mm_segment_t old_fs;
398                 int err;
399 
400                 old_fs = get_fs();
401                 set_fs(KERNEL_DS);
402                 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
403                 set_fs(old_fs);
404                 if (!err && put_user(offset, uoffset))
405                         err = -EFAULT;
406                 return err;
407         }
408 
409         case SNAPSHOT_CREATE_IMAGE:
410                 return snapshot_ioctl(file, cmd,
411                                       (unsigned long) compat_ptr(arg));
412 
413         case SNAPSHOT_SET_SWAP_AREA: {
414                 struct compat_resume_swap_area __user *u_swap_area =
415                         compat_ptr(arg);
416                 struct resume_swap_area swap_area;
417                 mm_segment_t old_fs;
418                 int err;
419 
420                 err = get_user(swap_area.offset, &u_swap_area->offset);
421                 err |= get_user(swap_area.dev, &u_swap_area->dev);
422                 if (err)
423                         return -EFAULT;
424                 old_fs = get_fs();
425                 set_fs(KERNEL_DS);
426                 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
427                                      (unsigned long) &swap_area);
428                 set_fs(old_fs);
429                 return err;
430         }
431 
432         default:
433                 return snapshot_ioctl(file, cmd, arg);
434         }
435 }
436 
437 #endif /* CONFIG_COMPAT */
438 
439 static const struct file_operations snapshot_fops = {
440         .open = snapshot_open,
441         .release = snapshot_release,
442         .read = snapshot_read,
443         .write = snapshot_write,
444         .llseek = no_llseek,
445         .unlocked_ioctl = snapshot_ioctl,
446 #ifdef CONFIG_COMPAT
447         .compat_ioctl = snapshot_compat_ioctl,
448 #endif
449 };
450 
451 static struct miscdevice snapshot_device = {
452         .minor = SNAPSHOT_MINOR,
453         .name = "snapshot",
454         .fops = &snapshot_fops,
455 };
456 
457 static int __init snapshot_device_init(void)
458 {
459         return misc_register(&snapshot_device);
460 };
461 
462 device_initcall(snapshot_device_init);
463 

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