xref: /openbmc/linux/kernel/power/user.c (revision 6ee73861) 
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 #include <scsi/scsi_scan.h>
27 
28 #include <asm/uaccess.h>
29 
30 #include "power.h"
31 
32 /*
33  * NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
34  * will be removed in the future.  They are only preserved here for
35  * compatibility with existing userland utilities.
36  */
37 #define SNAPSHOT_SET_SWAP_FILE	_IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
38 #define SNAPSHOT_PMOPS		_IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
39 
40 #define PMOPS_PREPARE	1
41 #define PMOPS_ENTER	2
42 #define PMOPS_FINISH	3
43 
44 /*
45  * NOTE: The following ioctl definitions are wrong and have been replaced with
46  * correct ones.  They are only preserved here for compatibility with existing
47  * userland utilities and will be removed in the future.
48  */
49 #define SNAPSHOT_ATOMIC_SNAPSHOT	_IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
50 #define SNAPSHOT_SET_IMAGE_SIZE		_IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
51 #define SNAPSHOT_AVAIL_SWAP		_IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
52 #define SNAPSHOT_GET_SWAP_PAGE		_IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
53 
54 
55 #define SNAPSHOT_MINOR	231
56 
57 static struct snapshot_data {
58 	struct snapshot_handle handle;
59 	int swap;
60 	int mode;
61 	char frozen;
62 	char ready;
63 	char platform_support;
64 } snapshot_state;
65 
66 atomic_t snapshot_device_available = ATOMIC_INIT(1);
67 
68 static int snapshot_open(struct inode *inode, struct file *filp)
69 {
70 	struct snapshot_data *data;
71 	int error;
72 
73 	mutex_lock(&pm_mutex);
74 
75 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
76 		error = -EBUSY;
77 		goto Unlock;
78 	}
79 
80 	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
81 		atomic_inc(&snapshot_device_available);
82 		error = -ENOSYS;
83 		goto Unlock;
84 	}
85 	if(create_basic_memory_bitmaps()) {
86 		atomic_inc(&snapshot_device_available);
87 		error = -ENOMEM;
88 		goto Unlock;
89 	}
90 	nonseekable_open(inode, filp);
91 	data = &snapshot_state;
92 	filp->private_data = data;
93 	memset(&data->handle, 0, sizeof(struct snapshot_handle));
94 	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
95 		/* Hibernating.  The image device should be accessible. */
96 		data->swap = swsusp_resume_device ?
97 			swap_type_of(swsusp_resume_device, 0, NULL) : -1;
98 		data->mode = O_RDONLY;
99 		error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
100 		if (error)
101 			pm_notifier_call_chain(PM_POST_HIBERNATION);
102 	} else {
103 		/*
104 		 * Resuming.  We may need to wait for the image device to
105 		 * appear.
106 		 */
107 		wait_for_device_probe();
108 		scsi_complete_async_scans();
109 
110 		data->swap = -1;
111 		data->mode = O_WRONLY;
112 		error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
113 		if (error)
114 			pm_notifier_call_chain(PM_POST_RESTORE);
115 	}
116 	if (error)
117 		atomic_inc(&snapshot_device_available);
118 	data->frozen = 0;
119 	data->ready = 0;
120 	data->platform_support = 0;
121 
122  Unlock:
123 	mutex_unlock(&pm_mutex);
124 
125 	return error;
126 }
127 
128 static int snapshot_release(struct inode *inode, struct file *filp)
129 {
130 	struct snapshot_data *data;
131 
132 	mutex_lock(&pm_mutex);
133 
134 	swsusp_free();
135 	free_basic_memory_bitmaps();
136 	data = filp->private_data;
137 	free_all_swap_pages(data->swap);
138 	if (data->frozen)
139 		thaw_processes();
140 	pm_notifier_call_chain(data->mode == O_WRONLY ?
141 			PM_POST_HIBERNATION : PM_POST_RESTORE);
142 	atomic_inc(&snapshot_device_available);
143 
144 	mutex_unlock(&pm_mutex);
145 
146 	return 0;
147 }
148 
149 static ssize_t snapshot_read(struct file *filp, char __user *buf,
150                              size_t count, loff_t *offp)
151 {
152 	struct snapshot_data *data;
153 	ssize_t res;
154 
155 	mutex_lock(&pm_mutex);
156 
157 	data = filp->private_data;
158 	if (!data->ready) {
159 		res = -ENODATA;
160 		goto Unlock;
161 	}
162 	res = snapshot_read_next(&data->handle, count);
163 	if (res > 0) {
164 		if (copy_to_user(buf, data_of(data->handle), res))
165 			res = -EFAULT;
166 		else
167 			*offp = data->handle.offset;
168 	}
169 
170  Unlock:
171 	mutex_unlock(&pm_mutex);
172 
173 	return res;
174 }
175 
176 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
177                               size_t count, loff_t *offp)
178 {
179 	struct snapshot_data *data;
180 	ssize_t res;
181 
182 	mutex_lock(&pm_mutex);
183 
184 	data = filp->private_data;
185 	res = snapshot_write_next(&data->handle, count);
186 	if (res > 0) {
187 		if (copy_from_user(data_of(data->handle), buf, res))
188 			res = -EFAULT;
189 		else
190 			*offp = data->handle.offset;
191 	}
192 
193 	mutex_unlock(&pm_mutex);
194 
195 	return res;
196 }
197 
198 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
199 							unsigned long arg)
200 {
201 	int error = 0;
202 	struct snapshot_data *data;
203 	loff_t size;
204 	sector_t offset;
205 
206 	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
207 		return -ENOTTY;
208 	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
209 		return -ENOTTY;
210 	if (!capable(CAP_SYS_ADMIN))
211 		return -EPERM;
212 
213 	if (!mutex_trylock(&pm_mutex))
214 		return -EBUSY;
215 
216 	data = filp->private_data;
217 
218 	switch (cmd) {
219 
220 	case SNAPSHOT_FREEZE:
221 		if (data->frozen)
222 			break;
223 
224 		printk("Syncing filesystems ... ");
225 		sys_sync();
226 		printk("done.\n");
227 
228 		error = usermodehelper_disable();
229 		if (error)
230 			break;
231 
232 		error = freeze_processes();
233 		if (error) {
234 			thaw_processes();
235 			usermodehelper_enable();
236 		}
237 		if (!error)
238 			data->frozen = 1;
239 		break;
240 
241 	case SNAPSHOT_UNFREEZE:
242 		if (!data->frozen || data->ready)
243 			break;
244 		thaw_processes();
245 		usermodehelper_enable();
246 		data->frozen = 0;
247 		break;
248 
249 	case SNAPSHOT_CREATE_IMAGE:
250 	case SNAPSHOT_ATOMIC_SNAPSHOT:
251 		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
252 			error = -EPERM;
253 			break;
254 		}
255 		error = hibernation_snapshot(data->platform_support);
256 		if (!error)
257 			error = put_user(in_suspend, (int __user *)arg);
258 		if (!error)
259 			data->ready = 1;
260 		break;
261 
262 	case SNAPSHOT_ATOMIC_RESTORE:
263 		snapshot_write_finalize(&data->handle);
264 		if (data->mode != O_WRONLY || !data->frozen ||
265 		    !snapshot_image_loaded(&data->handle)) {
266 			error = -EPERM;
267 			break;
268 		}
269 		error = hibernation_restore(data->platform_support);
270 		break;
271 
272 	case SNAPSHOT_FREE:
273 		swsusp_free();
274 		memset(&data->handle, 0, sizeof(struct snapshot_handle));
275 		data->ready = 0;
276 		break;
277 
278 	case SNAPSHOT_PREF_IMAGE_SIZE:
279 	case SNAPSHOT_SET_IMAGE_SIZE:
280 		image_size = arg;
281 		break;
282 
283 	case SNAPSHOT_GET_IMAGE_SIZE:
284 		if (!data->ready) {
285 			error = -ENODATA;
286 			break;
287 		}
288 		size = snapshot_get_image_size();
289 		size <<= PAGE_SHIFT;
290 		error = put_user(size, (loff_t __user *)arg);
291 		break;
292 
293 	case SNAPSHOT_AVAIL_SWAP_SIZE:
294 	case SNAPSHOT_AVAIL_SWAP:
295 		size = count_swap_pages(data->swap, 1);
296 		size <<= PAGE_SHIFT;
297 		error = put_user(size, (loff_t __user *)arg);
298 		break;
299 
300 	case SNAPSHOT_ALLOC_SWAP_PAGE:
301 	case SNAPSHOT_GET_SWAP_PAGE:
302 		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
303 			error = -ENODEV;
304 			break;
305 		}
306 		offset = alloc_swapdev_block(data->swap);
307 		if (offset) {
308 			offset <<= PAGE_SHIFT;
309 			error = put_user(offset, (loff_t __user *)arg);
310 		} else {
311 			error = -ENOSPC;
312 		}
313 		break;
314 
315 	case SNAPSHOT_FREE_SWAP_PAGES:
316 		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
317 			error = -ENODEV;
318 			break;
319 		}
320 		free_all_swap_pages(data->swap);
321 		break;
322 
323 	case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
324 		if (!swsusp_swap_in_use()) {
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 (!data->frozen) {
345 			error = -EPERM;
346 			break;
347 		}
348 		/*
349 		 * Tasks are frozen and the notifiers have been called with
350 		 * PM_HIBERNATION_PREPARE
351 		 */
352 		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
353 		break;
354 
355 	case SNAPSHOT_PLATFORM_SUPPORT:
356 		data->platform_support = !!arg;
357 		break;
358 
359 	case SNAPSHOT_POWER_OFF:
360 		if (data->platform_support)
361 			error = hibernation_platform_enter();
362 		break;
363 
364 	case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
365 		error = -EINVAL;
366 
367 		switch (arg) {
368 
369 		case PMOPS_PREPARE:
370 			data->platform_support = 1;
371 			error = 0;
372 			break;
373 
374 		case PMOPS_ENTER:
375 			if (data->platform_support)
376 				error = hibernation_platform_enter();
377 			break;
378 
379 		case PMOPS_FINISH:
380 			if (data->platform_support)
381 				error = 0;
382 			break;
383 
384 		default:
385 			printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
386 
387 		}
388 		break;
389 
390 	case SNAPSHOT_SET_SWAP_AREA:
391 		if (swsusp_swap_in_use()) {
392 			error = -EPERM;
393 		} else {
394 			struct resume_swap_area swap_area;
395 			dev_t swdev;
396 
397 			error = copy_from_user(&swap_area, (void __user *)arg,
398 					sizeof(struct resume_swap_area));
399 			if (error) {
400 				error = -EFAULT;
401 				break;
402 			}
403 
404 			/*
405 			 * User space encodes device types as two-byte values,
406 			 * so we need to recode them
407 			 */
408 			swdev = old_decode_dev(swap_area.dev);
409 			if (swdev) {
410 				offset = swap_area.offset;
411 				data->swap = swap_type_of(swdev, offset, NULL);
412 				if (data->swap < 0)
413 					error = -ENODEV;
414 			} else {
415 				data->swap = -1;
416 				error = -EINVAL;
417 			}
418 		}
419 		break;
420 
421 	default:
422 		error = -ENOTTY;
423 
424 	}
425 
426 	mutex_unlock(&pm_mutex);
427 
428 	return error;
429 }
430 
431 static const struct file_operations snapshot_fops = {
432 	.open = snapshot_open,
433 	.release = snapshot_release,
434 	.read = snapshot_read,
435 	.write = snapshot_write,
436 	.llseek = no_llseek,
437 	.unlocked_ioctl = snapshot_ioctl,
438 };
439 
440 static struct miscdevice snapshot_device = {
441 	.minor = SNAPSHOT_MINOR,
442 	.name = "snapshot",
443 	.fops = &snapshot_fops,
444 };
445 
446 static int __init snapshot_device_init(void)
447 {
448 	return misc_register(&snapshot_device);
449 };
450 
451 device_initcall(snapshot_device_init);
452