xref: /openbmc/linux/kernel/power/user.c (revision 6a108a14) 
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_RDONLY ?
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 	loff_t pg_offp = *offp & ~PAGE_MASK;
155 
156 	mutex_lock(&pm_mutex);
157 
158 	data = filp->private_data;
159 	if (!data->ready) {
160 		res = -ENODATA;
161 		goto Unlock;
162 	}
163 	if (!pg_offp) { /* on page boundary? */
164 		res = snapshot_read_next(&data->handle);
165 		if (res <= 0)
166 			goto Unlock;
167 	} else {
168 		res = PAGE_SIZE - pg_offp;
169 	}
170 
171 	res = simple_read_from_buffer(buf, count, &pg_offp,
172 			data_of(data->handle), res);
173 	if (res > 0)
174 		*offp += res;
175 
176  Unlock:
177 	mutex_unlock(&pm_mutex);
178 
179 	return res;
180 }
181 
182 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
183                               size_t count, loff_t *offp)
184 {
185 	struct snapshot_data *data;
186 	ssize_t res;
187 	loff_t pg_offp = *offp & ~PAGE_MASK;
188 
189 	mutex_lock(&pm_mutex);
190 
191 	data = filp->private_data;
192 
193 	if (!pg_offp) {
194 		res = snapshot_write_next(&data->handle);
195 		if (res <= 0)
196 			goto unlock;
197 	} else {
198 		res = PAGE_SIZE - pg_offp;
199 	}
200 
201 	res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
202 			buf, count);
203 	if (res > 0)
204 		*offp += res;
205 unlock:
206 	mutex_unlock(&pm_mutex);
207 
208 	return res;
209 }
210 
211 static void snapshot_deprecated_ioctl(unsigned int cmd)
212 {
213 	if (printk_ratelimit())
214 		printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will "
215 				"be removed soon, update your suspend-to-disk "
216 				"utilities\n",
217 				__builtin_return_address(0), cmd);
218 }
219 
220 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
221 							unsigned long arg)
222 {
223 	int error = 0;
224 	struct snapshot_data *data;
225 	loff_t size;
226 	sector_t offset;
227 
228 	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
229 		return -ENOTTY;
230 	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
231 		return -ENOTTY;
232 	if (!capable(CAP_SYS_ADMIN))
233 		return -EPERM;
234 
235 	if (!mutex_trylock(&pm_mutex))
236 		return -EBUSY;
237 
238 	data = filp->private_data;
239 
240 	switch (cmd) {
241 
242 	case SNAPSHOT_FREEZE:
243 		if (data->frozen)
244 			break;
245 
246 		printk("Syncing filesystems ... ");
247 		sys_sync();
248 		printk("done.\n");
249 
250 		error = usermodehelper_disable();
251 		if (error)
252 			break;
253 
254 		error = freeze_processes();
255 		if (error) {
256 			thaw_processes();
257 			usermodehelper_enable();
258 		}
259 		if (!error)
260 			data->frozen = 1;
261 		break;
262 
263 	case SNAPSHOT_UNFREEZE:
264 		if (!data->frozen || data->ready)
265 			break;
266 		pm_restore_gfp_mask();
267 		thaw_processes();
268 		usermodehelper_enable();
269 		data->frozen = 0;
270 		break;
271 
272 	case SNAPSHOT_ATOMIC_SNAPSHOT:
273 		snapshot_deprecated_ioctl(cmd);
274 	case SNAPSHOT_CREATE_IMAGE:
275 		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
276 			error = -EPERM;
277 			break;
278 		}
279 		pm_restore_gfp_mask();
280 		error = hibernation_snapshot(data->platform_support);
281 		if (!error)
282 			error = put_user(in_suspend, (int __user *)arg);
283 		if (!error)
284 			data->ready = 1;
285 		break;
286 
287 	case SNAPSHOT_ATOMIC_RESTORE:
288 		snapshot_write_finalize(&data->handle);
289 		if (data->mode != O_WRONLY || !data->frozen ||
290 		    !snapshot_image_loaded(&data->handle)) {
291 			error = -EPERM;
292 			break;
293 		}
294 		error = hibernation_restore(data->platform_support);
295 		break;
296 
297 	case SNAPSHOT_FREE:
298 		swsusp_free();
299 		memset(&data->handle, 0, sizeof(struct snapshot_handle));
300 		data->ready = 0;
301 		break;
302 
303 	case SNAPSHOT_SET_IMAGE_SIZE:
304 		snapshot_deprecated_ioctl(cmd);
305 	case SNAPSHOT_PREF_IMAGE_SIZE:
306 		image_size = arg;
307 		break;
308 
309 	case SNAPSHOT_GET_IMAGE_SIZE:
310 		if (!data->ready) {
311 			error = -ENODATA;
312 			break;
313 		}
314 		size = snapshot_get_image_size();
315 		size <<= PAGE_SHIFT;
316 		error = put_user(size, (loff_t __user *)arg);
317 		break;
318 
319 	case SNAPSHOT_AVAIL_SWAP:
320 		snapshot_deprecated_ioctl(cmd);
321 	case SNAPSHOT_AVAIL_SWAP_SIZE:
322 		size = count_swap_pages(data->swap, 1);
323 		size <<= PAGE_SHIFT;
324 		error = put_user(size, (loff_t __user *)arg);
325 		break;
326 
327 	case SNAPSHOT_GET_SWAP_PAGE:
328 		snapshot_deprecated_ioctl(cmd);
329 	case SNAPSHOT_ALLOC_SWAP_PAGE:
330 		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
331 			error = -ENODEV;
332 			break;
333 		}
334 		offset = alloc_swapdev_block(data->swap);
335 		if (offset) {
336 			offset <<= PAGE_SHIFT;
337 			error = put_user(offset, (loff_t __user *)arg);
338 		} else {
339 			error = -ENOSPC;
340 		}
341 		break;
342 
343 	case SNAPSHOT_FREE_SWAP_PAGES:
344 		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
345 			error = -ENODEV;
346 			break;
347 		}
348 		free_all_swap_pages(data->swap);
349 		break;
350 
351 	case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
352 		snapshot_deprecated_ioctl(cmd);
353 		if (!swsusp_swap_in_use()) {
354 			/*
355 			 * User space encodes device types as two-byte values,
356 			 * so we need to recode them
357 			 */
358 			if (old_decode_dev(arg)) {
359 				data->swap = swap_type_of(old_decode_dev(arg),
360 							0, NULL);
361 				if (data->swap < 0)
362 					error = -ENODEV;
363 			} else {
364 				data->swap = -1;
365 				error = -EINVAL;
366 			}
367 		} else {
368 			error = -EPERM;
369 		}
370 		break;
371 
372 	case SNAPSHOT_S2RAM:
373 		if (!data->frozen) {
374 			error = -EPERM;
375 			break;
376 		}
377 		/*
378 		 * Tasks are frozen and the notifiers have been called with
379 		 * PM_HIBERNATION_PREPARE
380 		 */
381 		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
382 		break;
383 
384 	case SNAPSHOT_PLATFORM_SUPPORT:
385 		data->platform_support = !!arg;
386 		break;
387 
388 	case SNAPSHOT_POWER_OFF:
389 		if (data->platform_support)
390 			error = hibernation_platform_enter();
391 		break;
392 
393 	case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
394 		snapshot_deprecated_ioctl(cmd);
395 		error = -EINVAL;
396 
397 		switch (arg) {
398 
399 		case PMOPS_PREPARE:
400 			data->platform_support = 1;
401 			error = 0;
402 			break;
403 
404 		case PMOPS_ENTER:
405 			if (data->platform_support)
406 				error = hibernation_platform_enter();
407 			break;
408 
409 		case PMOPS_FINISH:
410 			if (data->platform_support)
411 				error = 0;
412 			break;
413 
414 		default:
415 			printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
416 
417 		}
418 		break;
419 
420 	case SNAPSHOT_SET_SWAP_AREA:
421 		if (swsusp_swap_in_use()) {
422 			error = -EPERM;
423 		} else {
424 			struct resume_swap_area swap_area;
425 			dev_t swdev;
426 
427 			error = copy_from_user(&swap_area, (void __user *)arg,
428 					sizeof(struct resume_swap_area));
429 			if (error) {
430 				error = -EFAULT;
431 				break;
432 			}
433 
434 			/*
435 			 * User space encodes device types as two-byte values,
436 			 * so we need to recode them
437 			 */
438 			swdev = new_decode_dev(swap_area.dev);
439 			if (swdev) {
440 				offset = swap_area.offset;
441 				data->swap = swap_type_of(swdev, offset, NULL);
442 				if (data->swap < 0)
443 					error = -ENODEV;
444 			} else {
445 				data->swap = -1;
446 				error = -EINVAL;
447 			}
448 		}
449 		break;
450 
451 	default:
452 		error = -ENOTTY;
453 
454 	}
455 
456 	mutex_unlock(&pm_mutex);
457 
458 	return error;
459 }
460 
461 static const struct file_operations snapshot_fops = {
462 	.open = snapshot_open,
463 	.release = snapshot_release,
464 	.read = snapshot_read,
465 	.write = snapshot_write,
466 	.llseek = no_llseek,
467 	.unlocked_ioctl = snapshot_ioctl,
468 };
469 
470 static struct miscdevice snapshot_device = {
471 	.minor = SNAPSHOT_MINOR,
472 	.name = "snapshot",
473 	.fops = &snapshot_fops,
474 };
475 
476 static int __init snapshot_device_init(void)
477 {
478 	return misc_register(&snapshot_device);
479 };
480 
481 device_initcall(snapshot_device_init);
482