Commit | Line | Data |
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6e1819d6 RW |
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/string.h> | |
15 | #include <linux/device.h> | |
16 | #include <linux/miscdevice.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/swap.h> | |
19 | #include <linux/swapops.h> | |
20 | #include <linux/pm.h> | |
21 | #include <linux/fs.h> | |
22 | ||
23 | #include <asm/uaccess.h> | |
24 | ||
25 | #include "power.h" | |
26 | ||
27 | #define SNAPSHOT_MINOR 231 | |
28 | ||
29 | static struct snapshot_data { | |
30 | struct snapshot_handle handle; | |
31 | int swap; | |
32 | struct bitmap_page *bitmap; | |
33 | int mode; | |
34 | char frozen; | |
35 | char ready; | |
36 | } snapshot_state; | |
37 | ||
38 | static atomic_t device_available = ATOMIC_INIT(1); | |
39 | ||
40 | static int snapshot_open(struct inode *inode, struct file *filp) | |
41 | { | |
42 | struct snapshot_data *data; | |
43 | ||
44 | if (!atomic_add_unless(&device_available, -1, 0)) | |
45 | return -EBUSY; | |
46 | ||
47 | if ((filp->f_flags & O_ACCMODE) == O_RDWR) | |
48 | return -ENOSYS; | |
49 | ||
50 | nonseekable_open(inode, filp); | |
51 | data = &snapshot_state; | |
52 | filp->private_data = data; | |
53 | memset(&data->handle, 0, sizeof(struct snapshot_handle)); | |
54 | if ((filp->f_flags & O_ACCMODE) == O_RDONLY) { | |
55 | data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1; | |
56 | data->mode = O_RDONLY; | |
57 | } else { | |
58 | data->swap = -1; | |
59 | data->mode = O_WRONLY; | |
60 | } | |
61 | data->bitmap = NULL; | |
62 | data->frozen = 0; | |
63 | data->ready = 0; | |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
68 | static int snapshot_release(struct inode *inode, struct file *filp) | |
69 | { | |
70 | struct snapshot_data *data; | |
71 | ||
72 | swsusp_free(); | |
73 | data = filp->private_data; | |
74 | free_all_swap_pages(data->swap, data->bitmap); | |
75 | free_bitmap(data->bitmap); | |
76 | if (data->frozen) { | |
77 | down(&pm_sem); | |
78 | thaw_processes(); | |
79 | enable_nonboot_cpus(); | |
80 | up(&pm_sem); | |
81 | } | |
82 | atomic_inc(&device_available); | |
83 | return 0; | |
84 | } | |
85 | ||
86 | static ssize_t snapshot_read(struct file *filp, char __user *buf, | |
87 | size_t count, loff_t *offp) | |
88 | { | |
89 | struct snapshot_data *data; | |
90 | ssize_t res; | |
91 | ||
92 | data = filp->private_data; | |
93 | res = snapshot_read_next(&data->handle, count); | |
94 | if (res > 0) { | |
95 | if (copy_to_user(buf, data_of(data->handle), res)) | |
96 | res = -EFAULT; | |
97 | else | |
98 | *offp = data->handle.offset; | |
99 | } | |
100 | return res; | |
101 | } | |
102 | ||
103 | static ssize_t snapshot_write(struct file *filp, const char __user *buf, | |
104 | size_t count, loff_t *offp) | |
105 | { | |
106 | struct snapshot_data *data; | |
107 | ssize_t res; | |
108 | ||
109 | data = filp->private_data; | |
110 | res = snapshot_write_next(&data->handle, count); | |
111 | if (res > 0) { | |
112 | if (copy_from_user(data_of(data->handle), buf, res)) | |
113 | res = -EFAULT; | |
114 | else | |
115 | *offp = data->handle.offset; | |
116 | } | |
117 | return res; | |
118 | } | |
119 | ||
120 | static int snapshot_ioctl(struct inode *inode, struct file *filp, | |
121 | unsigned int cmd, unsigned long arg) | |
122 | { | |
123 | int error = 0; | |
124 | struct snapshot_data *data; | |
125 | loff_t offset, avail; | |
126 | ||
127 | if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) | |
128 | return -ENOTTY; | |
129 | if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) | |
130 | return -ENOTTY; | |
131 | if (!capable(CAP_SYS_ADMIN)) | |
132 | return -EPERM; | |
133 | ||
134 | data = filp->private_data; | |
135 | ||
136 | switch (cmd) { | |
137 | ||
138 | case SNAPSHOT_FREEZE: | |
139 | if (data->frozen) | |
140 | break; | |
141 | sys_sync(); | |
142 | down(&pm_sem); | |
143 | pm_prepare_console(); | |
144 | disable_nonboot_cpus(); | |
145 | if (freeze_processes()) { | |
146 | thaw_processes(); | |
147 | enable_nonboot_cpus(); | |
148 | pm_restore_console(); | |
149 | error = -EBUSY; | |
150 | } | |
151 | up(&pm_sem); | |
152 | if (!error) | |
153 | data->frozen = 1; | |
154 | break; | |
155 | ||
156 | case SNAPSHOT_UNFREEZE: | |
157 | if (!data->frozen) | |
158 | break; | |
159 | down(&pm_sem); | |
160 | thaw_processes(); | |
161 | enable_nonboot_cpus(); | |
162 | pm_restore_console(); | |
163 | up(&pm_sem); | |
164 | data->frozen = 0; | |
165 | break; | |
166 | ||
167 | case SNAPSHOT_ATOMIC_SNAPSHOT: | |
168 | if (data->mode != O_RDONLY || !data->frozen || data->ready) { | |
169 | error = -EPERM; | |
170 | break; | |
171 | } | |
172 | down(&pm_sem); | |
173 | /* Free memory before shutting down devices. */ | |
174 | error = swsusp_shrink_memory(); | |
175 | if (!error) { | |
176 | error = device_suspend(PMSG_FREEZE); | |
177 | if (!error) { | |
178 | in_suspend = 1; | |
179 | error = swsusp_suspend(); | |
180 | device_resume(); | |
181 | } | |
182 | } | |
183 | up(&pm_sem); | |
184 | if (!error) | |
185 | error = put_user(in_suspend, (unsigned int __user *)arg); | |
186 | if (!error) | |
187 | data->ready = 1; | |
188 | break; | |
189 | ||
190 | case SNAPSHOT_ATOMIC_RESTORE: | |
191 | if (data->mode != O_WRONLY || !data->frozen || | |
192 | !snapshot_image_loaded(&data->handle)) { | |
193 | error = -EPERM; | |
194 | break; | |
195 | } | |
196 | down(&pm_sem); | |
197 | pm_prepare_console(); | |
198 | error = device_suspend(PMSG_FREEZE); | |
199 | if (!error) { | |
200 | error = swsusp_resume(); | |
201 | device_resume(); | |
202 | } | |
203 | pm_restore_console(); | |
204 | up(&pm_sem); | |
205 | break; | |
206 | ||
207 | case SNAPSHOT_FREE: | |
208 | swsusp_free(); | |
209 | memset(&data->handle, 0, sizeof(struct snapshot_handle)); | |
210 | data->ready = 0; | |
211 | break; | |
212 | ||
213 | case SNAPSHOT_SET_IMAGE_SIZE: | |
214 | image_size = arg; | |
215 | break; | |
216 | ||
217 | case SNAPSHOT_AVAIL_SWAP: | |
218 | avail = count_swap_pages(data->swap, 1); | |
219 | avail <<= PAGE_SHIFT; | |
220 | error = put_user(avail, (loff_t __user *)arg); | |
221 | break; | |
222 | ||
223 | case SNAPSHOT_GET_SWAP_PAGE: | |
224 | if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { | |
225 | error = -ENODEV; | |
226 | break; | |
227 | } | |
228 | if (!data->bitmap) { | |
229 | data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0)); | |
230 | if (!data->bitmap) { | |
231 | error = -ENOMEM; | |
232 | break; | |
233 | } | |
234 | } | |
235 | offset = alloc_swap_page(data->swap, data->bitmap); | |
236 | if (offset) { | |
237 | offset <<= PAGE_SHIFT; | |
238 | error = put_user(offset, (loff_t __user *)arg); | |
239 | } else { | |
240 | error = -ENOSPC; | |
241 | } | |
242 | break; | |
243 | ||
244 | case SNAPSHOT_FREE_SWAP_PAGES: | |
245 | if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { | |
246 | error = -ENODEV; | |
247 | break; | |
248 | } | |
249 | free_all_swap_pages(data->swap, data->bitmap); | |
250 | free_bitmap(data->bitmap); | |
251 | data->bitmap = NULL; | |
252 | break; | |
253 | ||
254 | case SNAPSHOT_SET_SWAP_FILE: | |
255 | if (!data->bitmap) { | |
256 | /* | |
257 | * User space encodes device types as two-byte values, | |
258 | * so we need to recode them | |
259 | */ | |
260 | if (old_decode_dev(arg)) { | |
261 | data->swap = swap_type_of(old_decode_dev(arg)); | |
262 | if (data->swap < 0) | |
263 | error = -ENODEV; | |
264 | } else { | |
265 | data->swap = -1; | |
266 | error = -EINVAL; | |
267 | } | |
268 | } else { | |
269 | error = -EPERM; | |
270 | } | |
271 | break; | |
272 | ||
273 | default: | |
274 | error = -ENOTTY; | |
275 | ||
276 | } | |
277 | ||
278 | return error; | |
279 | } | |
280 | ||
281 | static struct file_operations snapshot_fops = { | |
282 | .open = snapshot_open, | |
283 | .release = snapshot_release, | |
284 | .read = snapshot_read, | |
285 | .write = snapshot_write, | |
286 | .llseek = no_llseek, | |
287 | .ioctl = snapshot_ioctl, | |
288 | }; | |
289 | ||
290 | static struct miscdevice snapshot_device = { | |
291 | .minor = SNAPSHOT_MINOR, | |
292 | .name = "snapshot", | |
293 | .fops = &snapshot_fops, | |
294 | }; | |
295 | ||
296 | static int __init snapshot_device_init(void) | |
297 | { | |
298 | return misc_register(&snapshot_device); | |
299 | }; | |
300 | ||
301 | device_initcall(snapshot_device_init); |