xref: /openbmc/linux/kernel/power/user.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 	res = snapshot_read_next(&data->handle, count);
103 	if (res > 0) {
104 		if (copy_to_user(buf, data_of(data->handle), res))
105 			res = -EFAULT;
106 		else
107 			*offp = data->handle.offset;
108 	}
109 	return res;
110 }
111 
112 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
113                               size_t count, loff_t *offp)
114 {
115 	struct snapshot_data *data;
116 	ssize_t res;
117 
118 	data = filp->private_data;
119 	res = snapshot_write_next(&data->handle, count);
120 	if (res > 0) {
121 		if (copy_from_user(data_of(data->handle), buf, res))
122 			res = -EFAULT;
123 		else
124 			*offp = data->handle.offset;
125 	}
126 	return res;
127 }
128 
129 static inline int platform_prepare(void)
130 {
131 	int error = 0;
132 
133 	if (hibernation_ops)
134 		error = hibernation_ops->prepare();
135 
136 	return error;
137 }
138 
139 static inline void platform_finish(void)
140 {
141 	if (hibernation_ops)
142 		hibernation_ops->finish();
143 }
144 
145 static inline int snapshot_suspend(int platform_suspend)
146 {
147 	int error;
148 
149 	mutex_lock(&pm_mutex);
150 	/* Free memory before shutting down devices. */
151 	error = swsusp_shrink_memory();
152 	if (error)
153 		goto Finish;
154 
155 	if (platform_suspend) {
156 		error = platform_prepare();
157 		if (error)
158 			goto Finish;
159 	}
160 	suspend_console();
161 	error = device_suspend(PMSG_FREEZE);
162 	if (error)
163 		goto Resume_devices;
164 
165 	error = disable_nonboot_cpus();
166 	if (!error) {
167 		in_suspend = 1;
168 		error = swsusp_suspend();
169 	}
170 	enable_nonboot_cpus();
171  Resume_devices:
172 	if (platform_suspend)
173 		platform_finish();
174 
175 	device_resume();
176 	resume_console();
177  Finish:
178 	mutex_unlock(&pm_mutex);
179 	return error;
180 }
181 
182 static inline int snapshot_restore(int platform_suspend)
183 {
184 	int error;
185 
186 	mutex_lock(&pm_mutex);
187 	pm_prepare_console();
188 	if (platform_suspend) {
189 		error = platform_prepare();
190 		if (error)
191 			goto Finish;
192 	}
193 	suspend_console();
194 	error = device_suspend(PMSG_PRETHAW);
195 	if (error)
196 		goto Resume_devices;
197 
198 	error = disable_nonboot_cpus();
199 	if (!error)
200 		error = swsusp_resume();
201 
202 	enable_nonboot_cpus();
203  Resume_devices:
204 	if (platform_suspend)
205 		platform_finish();
206 
207 	device_resume();
208 	resume_console();
209  Finish:
210 	pm_restore_console();
211 	mutex_unlock(&pm_mutex);
212 	return error;
213 }
214 
215 static int snapshot_ioctl(struct inode *inode, struct file *filp,
216                           unsigned int cmd, unsigned long arg)
217 {
218 	int error = 0;
219 	struct snapshot_data *data;
220 	loff_t avail;
221 	sector_t offset;
222 
223 	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
224 		return -ENOTTY;
225 	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
226 		return -ENOTTY;
227 	if (!capable(CAP_SYS_ADMIN))
228 		return -EPERM;
229 
230 	data = filp->private_data;
231 
232 	switch (cmd) {
233 
234 	case SNAPSHOT_FREEZE:
235 		if (data->frozen)
236 			break;
237 		mutex_lock(&pm_mutex);
238 		if (freeze_processes()) {
239 			thaw_processes();
240 			error = -EBUSY;
241 		}
242 		mutex_unlock(&pm_mutex);
243 		if (!error)
244 			data->frozen = 1;
245 		break;
246 
247 	case SNAPSHOT_UNFREEZE:
248 		if (!data->frozen)
249 			break;
250 		mutex_lock(&pm_mutex);
251 		thaw_processes();
252 		mutex_unlock(&pm_mutex);
253 		data->frozen = 0;
254 		break;
255 
256 	case SNAPSHOT_ATOMIC_SNAPSHOT:
257 		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
258 			error = -EPERM;
259 			break;
260 		}
261 		error = snapshot_suspend(data->platform_suspend);
262 		if (!error)
263 			error = put_user(in_suspend, (unsigned int __user *)arg);
264 		if (!error)
265 			data->ready = 1;
266 		break;
267 
268 	case SNAPSHOT_ATOMIC_RESTORE:
269 		snapshot_write_finalize(&data->handle);
270 		if (data->mode != O_WRONLY || !data->frozen ||
271 		    !snapshot_image_loaded(&data->handle)) {
272 			error = -EPERM;
273 			break;
274 		}
275 		error = snapshot_restore(data->platform_suspend);
276 		break;
277 
278 	case SNAPSHOT_FREE:
279 		swsusp_free();
280 		memset(&data->handle, 0, sizeof(struct snapshot_handle));
281 		data->ready = 0;
282 		break;
283 
284 	case SNAPSHOT_SET_IMAGE_SIZE:
285 		image_size = arg;
286 		break;
287 
288 	case SNAPSHOT_AVAIL_SWAP:
289 		avail = count_swap_pages(data->swap, 1);
290 		avail <<= PAGE_SHIFT;
291 		error = put_user(avail, (loff_t __user *)arg);
292 		break;
293 
294 	case SNAPSHOT_GET_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, (sector_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_SET_SWAP_FILE:
317 		if (!swsusp_swap_in_use()) {
318 			/*
319 			 * User space encodes device types as two-byte values,
320 			 * so we need to recode them
321 			 */
322 			if (old_decode_dev(arg)) {
323 				data->swap = swap_type_of(old_decode_dev(arg),
324 							0, NULL);
325 				if (data->swap < 0)
326 					error = -ENODEV;
327 			} else {
328 				data->swap = -1;
329 				error = -EINVAL;
330 			}
331 		} else {
332 			error = -EPERM;
333 		}
334 		break;
335 
336 	case SNAPSHOT_S2RAM:
337 		if (!pm_ops) {
338 			error = -ENOSYS;
339 			break;
340 		}
341 
342 		if (!data->frozen) {
343 			error = -EPERM;
344 			break;
345 		}
346 
347 		if (!mutex_trylock(&pm_mutex)) {
348 			error = -EBUSY;
349 			break;
350 		}
351 
352 		if (pm_ops->prepare) {
353 			error = pm_ops->prepare(PM_SUSPEND_MEM);
354 			if (error)
355 				goto OutS3;
356 		}
357 
358 		/* Put devices to sleep */
359 		suspend_console();
360 		error = device_suspend(PMSG_SUSPEND);
361 		if (error) {
362 			printk(KERN_ERR "Failed to suspend some devices.\n");
363 		} else {
364 			error = disable_nonboot_cpus();
365 			if (!error) {
366 				/* Enter S3, system is already frozen */
367 				suspend_enter(PM_SUSPEND_MEM);
368 				enable_nonboot_cpus();
369 			}
370 			/* Wake up devices */
371 			device_resume();
372 		}
373 		resume_console();
374 		if (pm_ops->finish)
375 			pm_ops->finish(PM_SUSPEND_MEM);
376 
377  OutS3:
378 		mutex_unlock(&pm_mutex);
379 		break;
380 
381 	case SNAPSHOT_PMOPS:
382 		error = -EINVAL;
383 
384 		switch (arg) {
385 
386 		case PMOPS_PREPARE:
387 			if (hibernation_ops) {
388 				data->platform_suspend = 1;
389 				error = 0;
390 			} else {
391 				error = -ENOSYS;
392 			}
393 			break;
394 
395 		case PMOPS_ENTER:
396 			if (data->platform_suspend) {
397 				kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
398 				error = hibernation_ops->enter();
399 			}
400 			break;
401 
402 		case PMOPS_FINISH:
403 			if (data->platform_suspend)
404 				error = 0;
405 
406 			break;
407 
408 		default:
409 			printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
410 
411 		}
412 		break;
413 
414 	case SNAPSHOT_SET_SWAP_AREA:
415 		if (swsusp_swap_in_use()) {
416 			error = -EPERM;
417 		} else {
418 			struct resume_swap_area swap_area;
419 			dev_t swdev;
420 
421 			error = copy_from_user(&swap_area, (void __user *)arg,
422 					sizeof(struct resume_swap_area));
423 			if (error) {
424 				error = -EFAULT;
425 				break;
426 			}
427 
428 			/*
429 			 * User space encodes device types as two-byte values,
430 			 * so we need to recode them
431 			 */
432 			swdev = old_decode_dev(swap_area.dev);
433 			if (swdev) {
434 				offset = swap_area.offset;
435 				data->swap = swap_type_of(swdev, offset, NULL);
436 				if (data->swap < 0)
437 					error = -ENODEV;
438 			} else {
439 				data->swap = -1;
440 				error = -EINVAL;
441 			}
442 		}
443 		break;
444 
445 	default:
446 		error = -ENOTTY;
447 
448 	}
449 
450 	return error;
451 }
452 
453 static const struct file_operations snapshot_fops = {
454 	.open = snapshot_open,
455 	.release = snapshot_release,
456 	.read = snapshot_read,
457 	.write = snapshot_write,
458 	.llseek = no_llseek,
459 	.ioctl = snapshot_ioctl,
460 };
461 
462 static struct miscdevice snapshot_device = {
463 	.minor = SNAPSHOT_MINOR,
464 	.name = "snapshot",
465 	.fops = &snapshot_fops,
466 };
467 
468 static int __init snapshot_device_init(void)
469 {
470 	return misc_register(&snapshot_device);
471 };
472 
473 device_initcall(snapshot_device_init);
474