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 printk("Syncing filesystems ... "); 157 sys_sync(); 158 printk("done.\n"); 159 160 error = freeze_processes(); 161 if (error) 162 thaw_processes(); 163 } 164 if (error) 165 pm_notifier_call_chain(PM_POST_HIBERNATION); 166 mutex_unlock(&pm_mutex); 167 if (!error) 168 data->frozen = 1; 169 break; 170 171 case SNAPSHOT_UNFREEZE: 172 if (!data->frozen || data->ready) 173 break; 174 mutex_lock(&pm_mutex); 175 thaw_processes(); 176 pm_notifier_call_chain(PM_POST_HIBERNATION); 177 mutex_unlock(&pm_mutex); 178 data->frozen = 0; 179 break; 180 181 case SNAPSHOT_ATOMIC_SNAPSHOT: 182 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 183 error = -EPERM; 184 break; 185 } 186 error = hibernation_snapshot(data->platform_suspend); 187 if (!error) 188 error = put_user(in_suspend, (unsigned int __user *)arg); 189 if (!error) 190 data->ready = 1; 191 break; 192 193 case SNAPSHOT_ATOMIC_RESTORE: 194 snapshot_write_finalize(&data->handle); 195 if (data->mode != O_WRONLY || !data->frozen || 196 !snapshot_image_loaded(&data->handle)) { 197 error = -EPERM; 198 break; 199 } 200 error = hibernation_restore(data->platform_suspend); 201 break; 202 203 case SNAPSHOT_FREE: 204 swsusp_free(); 205 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 206 data->ready = 0; 207 break; 208 209 case SNAPSHOT_SET_IMAGE_SIZE: 210 image_size = arg; 211 break; 212 213 case SNAPSHOT_AVAIL_SWAP: 214 avail = count_swap_pages(data->swap, 1); 215 avail <<= PAGE_SHIFT; 216 error = put_user(avail, (loff_t __user *)arg); 217 break; 218 219 case SNAPSHOT_GET_SWAP_PAGE: 220 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 221 error = -ENODEV; 222 break; 223 } 224 offset = alloc_swapdev_block(data->swap); 225 if (offset) { 226 offset <<= PAGE_SHIFT; 227 error = put_user(offset, (sector_t __user *)arg); 228 } else { 229 error = -ENOSPC; 230 } 231 break; 232 233 case SNAPSHOT_FREE_SWAP_PAGES: 234 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 235 error = -ENODEV; 236 break; 237 } 238 free_all_swap_pages(data->swap); 239 break; 240 241 case SNAPSHOT_SET_SWAP_FILE: 242 if (!swsusp_swap_in_use()) { 243 /* 244 * User space encodes device types as two-byte values, 245 * so we need to recode them 246 */ 247 if (old_decode_dev(arg)) { 248 data->swap = swap_type_of(old_decode_dev(arg), 249 0, NULL); 250 if (data->swap < 0) 251 error = -ENODEV; 252 } else { 253 data->swap = -1; 254 error = -EINVAL; 255 } 256 } else { 257 error = -EPERM; 258 } 259 break; 260 261 case SNAPSHOT_S2RAM: 262 if (!data->frozen) { 263 error = -EPERM; 264 break; 265 } 266 if (!mutex_trylock(&pm_mutex)) { 267 error = -EBUSY; 268 break; 269 } 270 /* 271 * Tasks are frozen and the notifiers have been called with 272 * PM_HIBERNATION_PREPARE 273 */ 274 error = suspend_devices_and_enter(PM_SUSPEND_MEM); 275 mutex_unlock(&pm_mutex); 276 break; 277 278 case SNAPSHOT_PMOPS: 279 error = -EINVAL; 280 281 switch (arg) { 282 283 case PMOPS_PREPARE: 284 data->platform_suspend = 1; 285 error = 0; 286 break; 287 288 case PMOPS_ENTER: 289 if (data->platform_suspend) 290 error = hibernation_platform_enter(); 291 292 break; 293 294 case PMOPS_FINISH: 295 if (data->platform_suspend) 296 error = 0; 297 298 break; 299 300 default: 301 printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg); 302 303 } 304 break; 305 306 case SNAPSHOT_SET_SWAP_AREA: 307 if (swsusp_swap_in_use()) { 308 error = -EPERM; 309 } else { 310 struct resume_swap_area swap_area; 311 dev_t swdev; 312 313 error = copy_from_user(&swap_area, (void __user *)arg, 314 sizeof(struct resume_swap_area)); 315 if (error) { 316 error = -EFAULT; 317 break; 318 } 319 320 /* 321 * User space encodes device types as two-byte values, 322 * so we need to recode them 323 */ 324 swdev = old_decode_dev(swap_area.dev); 325 if (swdev) { 326 offset = swap_area.offset; 327 data->swap = swap_type_of(swdev, offset, NULL); 328 if (data->swap < 0) 329 error = -ENODEV; 330 } else { 331 data->swap = -1; 332 error = -EINVAL; 333 } 334 } 335 break; 336 337 default: 338 error = -ENOTTY; 339 340 } 341 342 return error; 343 } 344 345 static const struct file_operations snapshot_fops = { 346 .open = snapshot_open, 347 .release = snapshot_release, 348 .read = snapshot_read, 349 .write = snapshot_write, 350 .llseek = no_llseek, 351 .ioctl = snapshot_ioctl, 352 }; 353 354 static struct miscdevice snapshot_device = { 355 .minor = SNAPSHOT_MINOR, 356 .name = "snapshot", 357 .fops = &snapshot_fops, 358 }; 359 360 static int __init snapshot_device_init(void) 361 { 362 return misc_register(&snapshot_device); 363 }; 364 365 device_initcall(snapshot_device_init); 366