xref: /linux/kernel/power/user.c (revision bf74b964775009071cf12f9d59d4dd5e388fbe0b) 
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);
476