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 if (!data->ready) 103 return -ENODATA; 104 res = snapshot_read_next(&data->handle, count); 105 if (res > 0) { 106 if (copy_to_user(buf, data_of(data->handle), res)) 107 res = -EFAULT; 108 else 109 *offp = data->handle.offset; 110 } 111 return res; 112 } 113 114 static ssize_t snapshot_write(struct file *filp, const char __user *buf, 115 size_t count, loff_t *offp) 116 { 117 struct snapshot_data *data; 118 ssize_t res; 119 120 data = filp->private_data; 121 res = snapshot_write_next(&data->handle, count); 122 if (res > 0) { 123 if (copy_from_user(data_of(data->handle), buf, res)) 124 res = -EFAULT; 125 else 126 *offp = data->handle.offset; 127 } 128 return res; 129 } 130 131 static int snapshot_ioctl(struct inode *inode, struct file *filp, 132 unsigned int cmd, unsigned long arg) 133 { 134 int error = 0; 135 struct snapshot_data *data; 136 loff_t avail; 137 sector_t offset; 138 139 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) 140 return -ENOTTY; 141 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) 142 return -ENOTTY; 143 if (!capable(CAP_SYS_ADMIN)) 144 return -EPERM; 145 146 data = filp->private_data; 147 148 switch (cmd) { 149 150 case SNAPSHOT_FREEZE: 151 if (data->frozen) 152 break; 153 mutex_lock(&pm_mutex); 154 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE); 155 if (!error) { 156 error = freeze_processes(); 157 if (error) 158 thaw_processes(); 159 } 160 if (error) 161 pm_notifier_call_chain(PM_POST_HIBERNATION); 162 mutex_unlock(&pm_mutex); 163 if (!error) 164 data->frozen = 1; 165 break; 166 167 case SNAPSHOT_UNFREEZE: 168 if (!data->frozen || data->ready) 169 break; 170 mutex_lock(&pm_mutex); 171 thaw_processes(); 172 pm_notifier_call_chain(PM_POST_HIBERNATION); 173 mutex_unlock(&pm_mutex); 174 data->frozen = 0; 175 break; 176 177 case SNAPSHOT_ATOMIC_SNAPSHOT: 178 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 179 error = -EPERM; 180 break; 181 } 182 error = hibernation_snapshot(data->platform_suspend); 183 if (!error) 184 error = put_user(in_suspend, (unsigned int __user *)arg); 185 if (!error) 186 data->ready = 1; 187 break; 188 189 case SNAPSHOT_ATOMIC_RESTORE: 190 snapshot_write_finalize(&data->handle); 191 if (data->mode != O_WRONLY || !data->frozen || 192 !snapshot_image_loaded(&data->handle)) { 193 error = -EPERM; 194 break; 195 } 196 error = hibernation_restore(data->platform_suspend); 197 break; 198 199 case SNAPSHOT_FREE: 200 swsusp_free(); 201 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 202 data->ready = 0; 203 break; 204 205 case SNAPSHOT_SET_IMAGE_SIZE: 206 image_size = arg; 207 break; 208 209 case SNAPSHOT_AVAIL_SWAP: 210 avail = count_swap_pages(data->swap, 1); 211 avail <<= PAGE_SHIFT; 212 error = put_user(avail, (loff_t __user *)arg); 213 break; 214 215 case SNAPSHOT_GET_SWAP_PAGE: 216 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 217 error = -ENODEV; 218 break; 219 } 220 offset = alloc_swapdev_block(data->swap); 221 if (offset) { 222 offset <<= PAGE_SHIFT; 223 error = put_user(offset, (sector_t __user *)arg); 224 } else { 225 error = -ENOSPC; 226 } 227 break; 228 229 case SNAPSHOT_FREE_SWAP_PAGES: 230 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 231 error = -ENODEV; 232 break; 233 } 234 free_all_swap_pages(data->swap); 235 break; 236 237 case SNAPSHOT_SET_SWAP_FILE: 238 if (!swsusp_swap_in_use()) { 239 /* 240 * User space encodes device types as two-byte values, 241 * so we need to recode them 242 */ 243 if (old_decode_dev(arg)) { 244 data->swap = swap_type_of(old_decode_dev(arg), 245 0, NULL); 246 if (data->swap < 0) 247 error = -ENODEV; 248 } else { 249 data->swap = -1; 250 error = -EINVAL; 251 } 252 } else { 253 error = -EPERM; 254 } 255 break; 256 257 case SNAPSHOT_S2RAM: 258 if (!data->frozen) { 259 error = -EPERM; 260 break; 261 } 262 if (!mutex_trylock(&pm_mutex)) { 263 error = -EBUSY; 264 break; 265 } 266 /* 267 * Tasks are frozen and the notifiers have been called with 268 * PM_HIBERNATION_PREPARE 269 */ 270 error = suspend_devices_and_enter(PM_SUSPEND_MEM); 271 mutex_unlock(&pm_mutex); 272 break; 273 274 case SNAPSHOT_PMOPS: 275 error = -EINVAL; 276 277 switch (arg) { 278 279 case PMOPS_PREPARE: 280 data->platform_suspend = 1; 281 error = 0; 282 break; 283 284 case PMOPS_ENTER: 285 if (data->platform_suspend) 286 error = hibernation_platform_enter(); 287 288 break; 289 290 case PMOPS_FINISH: 291 if (data->platform_suspend) 292 error = 0; 293 294 break; 295 296 default: 297 printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg); 298 299 } 300 break; 301 302 case SNAPSHOT_SET_SWAP_AREA: 303 if (swsusp_swap_in_use()) { 304 error = -EPERM; 305 } else { 306 struct resume_swap_area swap_area; 307 dev_t swdev; 308 309 error = copy_from_user(&swap_area, (void __user *)arg, 310 sizeof(struct resume_swap_area)); 311 if (error) { 312 error = -EFAULT; 313 break; 314 } 315 316 /* 317 * User space encodes device types as two-byte values, 318 * so we need to recode them 319 */ 320 swdev = old_decode_dev(swap_area.dev); 321 if (swdev) { 322 offset = swap_area.offset; 323 data->swap = swap_type_of(swdev, offset, NULL); 324 if (data->swap < 0) 325 error = -ENODEV; 326 } else { 327 data->swap = -1; 328 error = -EINVAL; 329 } 330 } 331 break; 332 333 default: 334 error = -ENOTTY; 335 336 } 337 338 return error; 339 } 340 341 static const struct file_operations snapshot_fops = { 342 .open = snapshot_open, 343 .release = snapshot_release, 344 .read = snapshot_read, 345 .write = snapshot_write, 346 .llseek = no_llseek, 347 .ioctl = snapshot_ioctl, 348 }; 349 350 static struct miscdevice snapshot_device = { 351 .minor = SNAPSHOT_MINOR, 352 .name = "snapshot", 353 .fops = &snapshot_fops, 354 }; 355 356 static int __init snapshot_device_init(void) 357 { 358 return misc_register(&snapshot_device); 359 }; 360 361 device_initcall(snapshot_device_init); 362