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/reboot.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 #include <linux/compat.h> 23 #include <linux/console.h> 24 #include <linux/cpu.h> 25 #include <linux/freezer.h> 26 27 #include <linux/uaccess.h> 28 29 #include "power.h" 30 31 32 #define SNAPSHOT_MINOR 231 33 34 static struct snapshot_data { 35 struct snapshot_handle handle; 36 int swap; 37 int mode; 38 bool frozen; 39 bool ready; 40 bool platform_support; 41 bool free_bitmaps; 42 } snapshot_state; 43 44 atomic_t snapshot_device_available = ATOMIC_INIT(1); 45 46 static int snapshot_open(struct inode *inode, struct file *filp) 47 { 48 struct snapshot_data *data; 49 int error, nr_calls = 0; 50 51 if (!hibernation_available()) 52 return -EPERM; 53 54 lock_system_sleep(); 55 56 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) { 57 error = -EBUSY; 58 goto Unlock; 59 } 60 61 if ((filp->f_flags & O_ACCMODE) == O_RDWR) { 62 atomic_inc(&snapshot_device_available); 63 error = -ENOSYS; 64 goto Unlock; 65 } 66 nonseekable_open(inode, filp); 67 data = &snapshot_state; 68 filp->private_data = data; 69 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 70 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) { 71 /* Hibernating. The image device should be accessible. */ 72 data->swap = swsusp_resume_device ? 73 swap_type_of(swsusp_resume_device, 0, NULL) : -1; 74 data->mode = O_RDONLY; 75 data->free_bitmaps = false; 76 error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls); 77 if (error) 78 __pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL); 79 } else { 80 /* 81 * Resuming. We may need to wait for the image device to 82 * appear. 83 */ 84 wait_for_device_probe(); 85 86 data->swap = -1; 87 data->mode = O_WRONLY; 88 error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls); 89 if (!error) { 90 error = create_basic_memory_bitmaps(); 91 data->free_bitmaps = !error; 92 } else 93 nr_calls--; 94 95 if (error) 96 __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); 97 } 98 if (error) 99 atomic_inc(&snapshot_device_available); 100 101 data->frozen = false; 102 data->ready = false; 103 data->platform_support = false; 104 105 Unlock: 106 unlock_system_sleep(); 107 108 return error; 109 } 110 111 static int snapshot_release(struct inode *inode, struct file *filp) 112 { 113 struct snapshot_data *data; 114 115 lock_system_sleep(); 116 117 swsusp_free(); 118 data = filp->private_data; 119 free_all_swap_pages(data->swap); 120 if (data->frozen) { 121 pm_restore_gfp_mask(); 122 free_basic_memory_bitmaps(); 123 thaw_processes(); 124 } else if (data->free_bitmaps) { 125 free_basic_memory_bitmaps(); 126 } 127 pm_notifier_call_chain(data->mode == O_RDONLY ? 128 PM_POST_HIBERNATION : PM_POST_RESTORE); 129 atomic_inc(&snapshot_device_available); 130 131 unlock_system_sleep(); 132 133 return 0; 134 } 135 136 static ssize_t snapshot_read(struct file *filp, char __user *buf, 137 size_t count, loff_t *offp) 138 { 139 struct snapshot_data *data; 140 ssize_t res; 141 loff_t pg_offp = *offp & ~PAGE_MASK; 142 143 lock_system_sleep(); 144 145 data = filp->private_data; 146 if (!data->ready) { 147 res = -ENODATA; 148 goto Unlock; 149 } 150 if (!pg_offp) { /* on page boundary? */ 151 res = snapshot_read_next(&data->handle); 152 if (res <= 0) 153 goto Unlock; 154 } else { 155 res = PAGE_SIZE - pg_offp; 156 } 157 158 res = simple_read_from_buffer(buf, count, &pg_offp, 159 data_of(data->handle), res); 160 if (res > 0) 161 *offp += res; 162 163 Unlock: 164 unlock_system_sleep(); 165 166 return res; 167 } 168 169 static ssize_t snapshot_write(struct file *filp, const char __user *buf, 170 size_t count, loff_t *offp) 171 { 172 struct snapshot_data *data; 173 ssize_t res; 174 loff_t pg_offp = *offp & ~PAGE_MASK; 175 176 lock_system_sleep(); 177 178 data = filp->private_data; 179 180 if (!pg_offp) { 181 res = snapshot_write_next(&data->handle); 182 if (res <= 0) 183 goto unlock; 184 } else { 185 res = PAGE_SIZE - pg_offp; 186 } 187 188 if (!data_of(data->handle)) { 189 res = -EINVAL; 190 goto unlock; 191 } 192 193 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp, 194 buf, count); 195 if (res > 0) 196 *offp += res; 197 unlock: 198 unlock_system_sleep(); 199 200 return res; 201 } 202 203 static long snapshot_ioctl(struct file *filp, unsigned int cmd, 204 unsigned long arg) 205 { 206 int error = 0; 207 struct snapshot_data *data; 208 loff_t size; 209 sector_t offset; 210 211 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) 212 return -ENOTTY; 213 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) 214 return -ENOTTY; 215 if (!capable(CAP_SYS_ADMIN)) 216 return -EPERM; 217 218 if (!mutex_trylock(&system_transition_mutex)) 219 return -EBUSY; 220 221 lock_device_hotplug(); 222 data = filp->private_data; 223 224 switch (cmd) { 225 226 case SNAPSHOT_FREEZE: 227 if (data->frozen) 228 break; 229 230 ksys_sync_helper(); 231 232 error = freeze_processes(); 233 if (error) 234 break; 235 236 error = create_basic_memory_bitmaps(); 237 if (error) 238 thaw_processes(); 239 else 240 data->frozen = true; 241 242 break; 243 244 case SNAPSHOT_UNFREEZE: 245 if (!data->frozen || data->ready) 246 break; 247 pm_restore_gfp_mask(); 248 free_basic_memory_bitmaps(); 249 data->free_bitmaps = false; 250 thaw_processes(); 251 data->frozen = false; 252 break; 253 254 case SNAPSHOT_CREATE_IMAGE: 255 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 256 error = -EPERM; 257 break; 258 } 259 pm_restore_gfp_mask(); 260 error = hibernation_snapshot(data->platform_support); 261 if (!error) { 262 error = put_user(in_suspend, (int __user *)arg); 263 data->ready = !freezer_test_done && !error; 264 freezer_test_done = false; 265 } 266 break; 267 268 case SNAPSHOT_ATOMIC_RESTORE: 269 snapshot_write_finalize(&data->handle); 270 if (data->mode != O_WRONLY || !data->frozen || 271 !snapshot_image_loaded(&data->handle)) { 272 error = -EPERM; 273 break; 274 } 275 error = hibernation_restore(data->platform_support); 276 break; 277 278 case SNAPSHOT_FREE: 279 swsusp_free(); 280 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 281 data->ready = false; 282 /* 283 * It is necessary to thaw kernel threads here, because 284 * SNAPSHOT_CREATE_IMAGE may be invoked directly after 285 * SNAPSHOT_FREE. In that case, if kernel threads were not 286 * thawed, the preallocation of memory carried out by 287 * hibernation_snapshot() might run into problems (i.e. it 288 * might fail or even deadlock). 289 */ 290 thaw_kernel_threads(); 291 break; 292 293 case SNAPSHOT_PREF_IMAGE_SIZE: 294 image_size = arg; 295 break; 296 297 case SNAPSHOT_GET_IMAGE_SIZE: 298 if (!data->ready) { 299 error = -ENODATA; 300 break; 301 } 302 size = snapshot_get_image_size(); 303 size <<= PAGE_SHIFT; 304 error = put_user(size, (loff_t __user *)arg); 305 break; 306 307 case SNAPSHOT_AVAIL_SWAP_SIZE: 308 size = count_swap_pages(data->swap, 1); 309 size <<= PAGE_SHIFT; 310 error = put_user(size, (loff_t __user *)arg); 311 break; 312 313 case SNAPSHOT_ALLOC_SWAP_PAGE: 314 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 315 error = -ENODEV; 316 break; 317 } 318 offset = alloc_swapdev_block(data->swap); 319 if (offset) { 320 offset <<= PAGE_SHIFT; 321 error = put_user(offset, (loff_t __user *)arg); 322 } else { 323 error = -ENOSPC; 324 } 325 break; 326 327 case SNAPSHOT_FREE_SWAP_PAGES: 328 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 329 error = -ENODEV; 330 break; 331 } 332 free_all_swap_pages(data->swap); 333 break; 334 335 case SNAPSHOT_S2RAM: 336 if (!data->frozen) { 337 error = -EPERM; 338 break; 339 } 340 /* 341 * Tasks are frozen and the notifiers have been called with 342 * PM_HIBERNATION_PREPARE 343 */ 344 error = suspend_devices_and_enter(PM_SUSPEND_MEM); 345 data->ready = false; 346 break; 347 348 case SNAPSHOT_PLATFORM_SUPPORT: 349 data->platform_support = !!arg; 350 break; 351 352 case SNAPSHOT_POWER_OFF: 353 if (data->platform_support) 354 error = hibernation_platform_enter(); 355 break; 356 357 case SNAPSHOT_SET_SWAP_AREA: 358 if (swsusp_swap_in_use()) { 359 error = -EPERM; 360 } else { 361 struct resume_swap_area swap_area; 362 dev_t swdev; 363 364 error = copy_from_user(&swap_area, (void __user *)arg, 365 sizeof(struct resume_swap_area)); 366 if (error) { 367 error = -EFAULT; 368 break; 369 } 370 371 /* 372 * User space encodes device types as two-byte values, 373 * so we need to recode them 374 */ 375 swdev = new_decode_dev(swap_area.dev); 376 if (swdev) { 377 offset = swap_area.offset; 378 data->swap = swap_type_of(swdev, offset, NULL); 379 if (data->swap < 0) 380 error = -ENODEV; 381 } else { 382 data->swap = -1; 383 error = -EINVAL; 384 } 385 } 386 break; 387 388 default: 389 error = -ENOTTY; 390 391 } 392 393 unlock_device_hotplug(); 394 mutex_unlock(&system_transition_mutex); 395 396 return error; 397 } 398 399 #ifdef CONFIG_COMPAT 400 401 struct compat_resume_swap_area { 402 compat_loff_t offset; 403 u32 dev; 404 } __packed; 405 406 static long 407 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 408 { 409 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t)); 410 411 switch (cmd) { 412 case SNAPSHOT_GET_IMAGE_SIZE: 413 case SNAPSHOT_AVAIL_SWAP_SIZE: 414 case SNAPSHOT_ALLOC_SWAP_PAGE: { 415 compat_loff_t __user *uoffset = compat_ptr(arg); 416 loff_t offset; 417 mm_segment_t old_fs; 418 int err; 419 420 old_fs = get_fs(); 421 set_fs(KERNEL_DS); 422 err = snapshot_ioctl(file, cmd, (unsigned long) &offset); 423 set_fs(old_fs); 424 if (!err && put_user(offset, uoffset)) 425 err = -EFAULT; 426 return err; 427 } 428 429 case SNAPSHOT_CREATE_IMAGE: 430 return snapshot_ioctl(file, cmd, 431 (unsigned long) compat_ptr(arg)); 432 433 case SNAPSHOT_SET_SWAP_AREA: { 434 struct compat_resume_swap_area __user *u_swap_area = 435 compat_ptr(arg); 436 struct resume_swap_area swap_area; 437 mm_segment_t old_fs; 438 int err; 439 440 err = get_user(swap_area.offset, &u_swap_area->offset); 441 err |= get_user(swap_area.dev, &u_swap_area->dev); 442 if (err) 443 return -EFAULT; 444 old_fs = get_fs(); 445 set_fs(KERNEL_DS); 446 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA, 447 (unsigned long) &swap_area); 448 set_fs(old_fs); 449 return err; 450 } 451 452 default: 453 return snapshot_ioctl(file, cmd, arg); 454 } 455 } 456 457 #endif /* CONFIG_COMPAT */ 458 459 static const struct file_operations snapshot_fops = { 460 .open = snapshot_open, 461 .release = snapshot_release, 462 .read = snapshot_read, 463 .write = snapshot_write, 464 .llseek = no_llseek, 465 .unlocked_ioctl = snapshot_ioctl, 466 #ifdef CONFIG_COMPAT 467 .compat_ioctl = snapshot_compat_ioctl, 468 #endif 469 }; 470 471 static struct miscdevice snapshot_device = { 472 .minor = SNAPSHOT_MINOR, 473 .name = "snapshot", 474 .fops = &snapshot_fops, 475 }; 476 477 static int __init snapshot_device_init(void) 478 { 479 return misc_register(&snapshot_device); 480 }; 481 482 device_initcall(snapshot_device_init); 483