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-rw-r--r--kernel/power/user.c301
1 files changed, 301 insertions, 0 deletions
diff --git a/kernel/power/user.c b/kernel/power/user.c
new file mode 100644
index 000000000000..8cabc405ca10
--- /dev/null
+++ b/kernel/power/user.c
@@ -0,0 +1,301 @@
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
29static 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
38static atomic_t device_available = ATOMIC_INIT(1);
39
40static 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
68static 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
86static 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
103static 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
120static 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
281static 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
290static struct miscdevice snapshot_device = {
291 .minor = SNAPSHOT_MINOR,
292 .name = "snapshot",
293 .fops = &snapshot_fops,
294};
295
296static int __init snapshot_device_init(void)
297{
298 return misc_register(&snapshot_device);
299};
300
301device_initcall(snapshot_device_init);
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