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 struct bitmap_page *bitmap; 37 int mode; 38 char frozen; 39 char ready; 40 } snapshot_state; 41 42 static atomic_t 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(&device_available, -1, 0)) 49 return -EBUSY; 50 51 if ((filp->f_flags & O_ACCMODE) == O_RDWR) 52 return -ENOSYS; 53 54 nonseekable_open(inode, filp); 55 data = &snapshot_state; 56 filp->private_data = data; 57 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 58 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) { 59 data->swap = swsusp_resume_device ? 60 swap_type_of(swsusp_resume_device, 0, NULL) : -1; 61 data->mode = O_RDONLY; 62 } else { 63 data->swap = -1; 64 data->mode = O_WRONLY; 65 } 66 data->bitmap = NULL; 67 data->frozen = 0; 68 data->ready = 0; 69 70 return 0; 71 } 72 73 static int snapshot_release(struct inode *inode, struct file *filp) 74 { 75 struct snapshot_data *data; 76 77 swsusp_free(); 78 data = filp->private_data; 79 free_all_swap_pages(data->swap, data->bitmap); 80 free_bitmap(data->bitmap); 81 if (data->frozen) { 82 mutex_lock(&pm_mutex); 83 thaw_processes(); 84 enable_nonboot_cpus(); 85 mutex_unlock(&pm_mutex); 86 } 87 atomic_inc(&device_available); 88 return 0; 89 } 90 91 static ssize_t snapshot_read(struct file *filp, char __user *buf, 92 size_t count, loff_t *offp) 93 { 94 struct snapshot_data *data; 95 ssize_t res; 96 97 data = filp->private_data; 98 res = snapshot_read_next(&data->handle, count); 99 if (res > 0) { 100 if (copy_to_user(buf, data_of(data->handle), res)) 101 res = -EFAULT; 102 else 103 *offp = data->handle.offset; 104 } 105 return res; 106 } 107 108 static ssize_t snapshot_write(struct file *filp, const char __user *buf, 109 size_t count, loff_t *offp) 110 { 111 struct snapshot_data *data; 112 ssize_t res; 113 114 data = filp->private_data; 115 res = snapshot_write_next(&data->handle, count); 116 if (res > 0) { 117 if (copy_from_user(data_of(data->handle), buf, res)) 118 res = -EFAULT; 119 else 120 *offp = data->handle.offset; 121 } 122 return res; 123 } 124 125 static int snapshot_ioctl(struct inode *inode, struct file *filp, 126 unsigned int cmd, unsigned long arg) 127 { 128 int error = 0; 129 struct snapshot_data *data; 130 loff_t avail; 131 sector_t offset; 132 133 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) 134 return -ENOTTY; 135 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) 136 return -ENOTTY; 137 if (!capable(CAP_SYS_ADMIN)) 138 return -EPERM; 139 140 data = filp->private_data; 141 142 switch (cmd) { 143 144 case SNAPSHOT_FREEZE: 145 if (data->frozen) 146 break; 147 mutex_lock(&pm_mutex); 148 error = disable_nonboot_cpus(); 149 if (!error) { 150 error = freeze_processes(); 151 if (error) { 152 thaw_processes(); 153 enable_nonboot_cpus(); 154 error = -EBUSY; 155 } 156 } 157 mutex_unlock(&pm_mutex); 158 if (!error) 159 data->frozen = 1; 160 break; 161 162 case SNAPSHOT_UNFREEZE: 163 if (!data->frozen) 164 break; 165 mutex_lock(&pm_mutex); 166 thaw_processes(); 167 enable_nonboot_cpus(); 168 mutex_unlock(&pm_mutex); 169 data->frozen = 0; 170 break; 171 172 case SNAPSHOT_ATOMIC_SNAPSHOT: 173 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 174 error = -EPERM; 175 break; 176 } 177 mutex_lock(&pm_mutex); 178 /* Free memory before shutting down devices. */ 179 error = swsusp_shrink_memory(); 180 if (!error) { 181 suspend_console(); 182 error = device_suspend(PMSG_FREEZE); 183 if (!error) { 184 in_suspend = 1; 185 error = swsusp_suspend(); 186 device_resume(); 187 } 188 resume_console(); 189 } 190 mutex_unlock(&pm_mutex); 191 if (!error) 192 error = put_user(in_suspend, (unsigned int __user *)arg); 193 if (!error) 194 data->ready = 1; 195 break; 196 197 case SNAPSHOT_ATOMIC_RESTORE: 198 snapshot_write_finalize(&data->handle); 199 if (data->mode != O_WRONLY || !data->frozen || 200 !snapshot_image_loaded(&data->handle)) { 201 error = -EPERM; 202 break; 203 } 204 mutex_lock(&pm_mutex); 205 pm_prepare_console(); 206 suspend_console(); 207 error = device_suspend(PMSG_PRETHAW); 208 if (!error) { 209 error = swsusp_resume(); 210 device_resume(); 211 } 212 resume_console(); 213 pm_restore_console(); 214 mutex_unlock(&pm_mutex); 215 break; 216 217 case SNAPSHOT_FREE: 218 swsusp_free(); 219 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 220 data->ready = 0; 221 break; 222 223 case SNAPSHOT_SET_IMAGE_SIZE: 224 image_size = arg; 225 break; 226 227 case SNAPSHOT_AVAIL_SWAP: 228 avail = count_swap_pages(data->swap, 1); 229 avail <<= PAGE_SHIFT; 230 error = put_user(avail, (loff_t __user *)arg); 231 break; 232 233 case SNAPSHOT_GET_SWAP_PAGE: 234 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 235 error = -ENODEV; 236 break; 237 } 238 if (!data->bitmap) { 239 data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0)); 240 if (!data->bitmap) { 241 error = -ENOMEM; 242 break; 243 } 244 } 245 offset = alloc_swapdev_block(data->swap, data->bitmap); 246 if (offset) { 247 offset <<= PAGE_SHIFT; 248 error = put_user(offset, (sector_t __user *)arg); 249 } else { 250 error = -ENOSPC; 251 } 252 break; 253 254 case SNAPSHOT_FREE_SWAP_PAGES: 255 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 256 error = -ENODEV; 257 break; 258 } 259 free_all_swap_pages(data->swap, data->bitmap); 260 free_bitmap(data->bitmap); 261 data->bitmap = NULL; 262 break; 263 264 case SNAPSHOT_SET_SWAP_FILE: 265 if (!data->bitmap) { 266 /* 267 * User space encodes device types as two-byte values, 268 * so we need to recode them 269 */ 270 if (old_decode_dev(arg)) { 271 data->swap = swap_type_of(old_decode_dev(arg), 272 0, NULL); 273 if (data->swap < 0) 274 error = -ENODEV; 275 } else { 276 data->swap = -1; 277 error = -EINVAL; 278 } 279 } else { 280 error = -EPERM; 281 } 282 break; 283 284 case SNAPSHOT_S2RAM: 285 if (!data->frozen) { 286 error = -EPERM; 287 break; 288 } 289 290 if (!mutex_trylock(&pm_mutex)) { 291 error = -EBUSY; 292 break; 293 } 294 295 if (pm_ops->prepare) { 296 error = pm_ops->prepare(PM_SUSPEND_MEM); 297 if (error) 298 goto OutS3; 299 } 300 301 /* Put devices to sleep */ 302 suspend_console(); 303 error = device_suspend(PMSG_SUSPEND); 304 if (error) { 305 printk(KERN_ERR "Failed to suspend some devices.\n"); 306 } else { 307 /* Enter S3, system is already frozen */ 308 suspend_enter(PM_SUSPEND_MEM); 309 310 /* Wake up devices */ 311 device_resume(); 312 } 313 resume_console(); 314 if (pm_ops->finish) 315 pm_ops->finish(PM_SUSPEND_MEM); 316 317 OutS3: 318 mutex_unlock(&pm_mutex); 319 break; 320 321 case SNAPSHOT_PMOPS: 322 switch (arg) { 323 324 case PMOPS_PREPARE: 325 if (pm_ops->prepare) { 326 error = pm_ops->prepare(PM_SUSPEND_DISK); 327 } 328 break; 329 330 case PMOPS_ENTER: 331 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); 332 error = pm_ops->enter(PM_SUSPEND_DISK); 333 break; 334 335 case PMOPS_FINISH: 336 if (pm_ops && pm_ops->finish) { 337 pm_ops->finish(PM_SUSPEND_DISK); 338 } 339 break; 340 341 default: 342 printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg); 343 error = -EINVAL; 344 345 } 346 break; 347 348 case SNAPSHOT_SET_SWAP_AREA: 349 if (data->bitmap) { 350 error = -EPERM; 351 } else { 352 struct resume_swap_area swap_area; 353 dev_t swdev; 354 355 error = copy_from_user(&swap_area, (void __user *)arg, 356 sizeof(struct resume_swap_area)); 357 if (error) { 358 error = -EFAULT; 359 break; 360 } 361 362 /* 363 * User space encodes device types as two-byte values, 364 * so we need to recode them 365 */ 366 swdev = old_decode_dev(swap_area.dev); 367 if (swdev) { 368 offset = swap_area.offset; 369 data->swap = swap_type_of(swdev, offset, NULL); 370 if (data->swap < 0) 371 error = -ENODEV; 372 } else { 373 data->swap = -1; 374 error = -EINVAL; 375 } 376 } 377 break; 378 379 default: 380 error = -ENOTTY; 381 382 } 383 384 return error; 385 } 386 387 static const struct file_operations snapshot_fops = { 388 .open = snapshot_open, 389 .release = snapshot_release, 390 .read = snapshot_read, 391 .write = snapshot_write, 392 .llseek = no_llseek, 393 .ioctl = snapshot_ioctl, 394 }; 395 396 static struct miscdevice snapshot_device = { 397 .minor = SNAPSHOT_MINOR, 398 .name = "snapshot", 399 .fops = &snapshot_fops, 400 }; 401 402 static int __init snapshot_device_init(void) 403 { 404 return misc_register(&snapshot_device); 405 }; 406 407 device_initcall(snapshot_device_init); 408