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/compat.h> 24 #include <linux/console.h> 25 #include <linux/cpu.h> 26 #include <linux/freezer.h> 27 28 #include <linux/uaccess.h> 29 30 #include "power.h" 31 32 33 #define SNAPSHOT_MINOR 231 34 35 static struct snapshot_data { 36 struct snapshot_handle handle; 37 int swap; 38 int mode; 39 bool frozen; 40 bool ready; 41 bool platform_support; 42 bool free_bitmaps; 43 } snapshot_state; 44 45 atomic_t snapshot_device_available = ATOMIC_INIT(1); 46 47 static int snapshot_open(struct inode *inode, struct file *filp) 48 { 49 struct snapshot_data *data; 50 int error, nr_calls = 0; 51 52 if (!hibernation_available()) 53 return -EPERM; 54 55 lock_system_sleep(); 56 57 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) { 58 error = -EBUSY; 59 goto Unlock; 60 } 61 62 if ((filp->f_flags & O_ACCMODE) == O_RDWR) { 63 atomic_inc(&snapshot_device_available); 64 error = -ENOSYS; 65 goto Unlock; 66 } 67 nonseekable_open(inode, filp); 68 data = &snapshot_state; 69 filp->private_data = data; 70 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 71 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) { 72 /* Hibernating. The image device should be accessible. */ 73 data->swap = swsusp_resume_device ? 74 swap_type_of(swsusp_resume_device, 0, NULL) : -1; 75 data->mode = O_RDONLY; 76 data->free_bitmaps = false; 77 error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls); 78 if (error) 79 __pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL); 80 } else { 81 /* 82 * Resuming. We may need to wait for the image device to 83 * appear. 84 */ 85 wait_for_device_probe(); 86 87 data->swap = -1; 88 data->mode = O_WRONLY; 89 error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls); 90 if (!error) { 91 error = create_basic_memory_bitmaps(); 92 data->free_bitmaps = !error; 93 } else 94 nr_calls--; 95 96 if (error) 97 __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); 98 } 99 if (error) 100 atomic_inc(&snapshot_device_available); 101 102 data->frozen = false; 103 data->ready = false; 104 data->platform_support = false; 105 106 Unlock: 107 unlock_system_sleep(); 108 109 return error; 110 } 111 112 static int snapshot_release(struct inode *inode, struct file *filp) 113 { 114 struct snapshot_data *data; 115 116 lock_system_sleep(); 117 118 swsusp_free(); 119 data = filp->private_data; 120 free_all_swap_pages(data->swap); 121 if (data->frozen) { 122 pm_restore_gfp_mask(); 123 free_basic_memory_bitmaps(); 124 thaw_processes(); 125 } else if (data->free_bitmaps) { 126 free_basic_memory_bitmaps(); 127 } 128 pm_notifier_call_chain(data->mode == O_RDONLY ? 129 PM_POST_HIBERNATION : PM_POST_RESTORE); 130 atomic_inc(&snapshot_device_available); 131 132 unlock_system_sleep(); 133 134 return 0; 135 } 136 137 static ssize_t snapshot_read(struct file *filp, char __user *buf, 138 size_t count, loff_t *offp) 139 { 140 struct snapshot_data *data; 141 ssize_t res; 142 loff_t pg_offp = *offp & ~PAGE_MASK; 143 144 lock_system_sleep(); 145 146 data = filp->private_data; 147 if (!data->ready) { 148 res = -ENODATA; 149 goto Unlock; 150 } 151 if (!pg_offp) { /* on page boundary? */ 152 res = snapshot_read_next(&data->handle); 153 if (res <= 0) 154 goto Unlock; 155 } else { 156 res = PAGE_SIZE - pg_offp; 157 } 158 159 res = simple_read_from_buffer(buf, count, &pg_offp, 160 data_of(data->handle), res); 161 if (res > 0) 162 *offp += res; 163 164 Unlock: 165 unlock_system_sleep(); 166 167 return res; 168 } 169 170 static ssize_t snapshot_write(struct file *filp, const char __user *buf, 171 size_t count, loff_t *offp) 172 { 173 struct snapshot_data *data; 174 ssize_t res; 175 loff_t pg_offp = *offp & ~PAGE_MASK; 176 177 lock_system_sleep(); 178 179 data = filp->private_data; 180 181 if (!pg_offp) { 182 res = snapshot_write_next(&data->handle); 183 if (res <= 0) 184 goto unlock; 185 } else { 186 res = PAGE_SIZE - pg_offp; 187 } 188 189 if (!data_of(data->handle)) { 190 res = -EINVAL; 191 goto unlock; 192 } 193 194 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp, 195 buf, count); 196 if (res > 0) 197 *offp += res; 198 unlock: 199 unlock_system_sleep(); 200 201 return res; 202 } 203 204 static long snapshot_ioctl(struct file *filp, unsigned int cmd, 205 unsigned long arg) 206 { 207 int error = 0; 208 struct snapshot_data *data; 209 loff_t size; 210 sector_t offset; 211 212 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) 213 return -ENOTTY; 214 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) 215 return -ENOTTY; 216 if (!capable(CAP_SYS_ADMIN)) 217 return -EPERM; 218 219 if (!mutex_trylock(&pm_mutex)) 220 return -EBUSY; 221 222 lock_device_hotplug(); 223 data = filp->private_data; 224 225 switch (cmd) { 226 227 case SNAPSHOT_FREEZE: 228 if (data->frozen) 229 break; 230 231 printk("Syncing filesystems ... "); 232 ksys_sync(); 233 printk("done.\n"); 234 235 error = freeze_processes(); 236 if (error) 237 break; 238 239 error = create_basic_memory_bitmaps(); 240 if (error) 241 thaw_processes(); 242 else 243 data->frozen = true; 244 245 break; 246 247 case SNAPSHOT_UNFREEZE: 248 if (!data->frozen || data->ready) 249 break; 250 pm_restore_gfp_mask(); 251 free_basic_memory_bitmaps(); 252 data->free_bitmaps = false; 253 thaw_processes(); 254 data->frozen = false; 255 break; 256 257 case SNAPSHOT_CREATE_IMAGE: 258 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 259 error = -EPERM; 260 break; 261 } 262 pm_restore_gfp_mask(); 263 error = hibernation_snapshot(data->platform_support); 264 if (!error) { 265 error = put_user(in_suspend, (int __user *)arg); 266 data->ready = !freezer_test_done && !error; 267 freezer_test_done = false; 268 } 269 break; 270 271 case SNAPSHOT_ATOMIC_RESTORE: 272 snapshot_write_finalize(&data->handle); 273 if (data->mode != O_WRONLY || !data->frozen || 274 !snapshot_image_loaded(&data->handle)) { 275 error = -EPERM; 276 break; 277 } 278 error = hibernation_restore(data->platform_support); 279 break; 280 281 case SNAPSHOT_FREE: 282 swsusp_free(); 283 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 284 data->ready = false; 285 /* 286 * It is necessary to thaw kernel threads here, because 287 * SNAPSHOT_CREATE_IMAGE may be invoked directly after 288 * SNAPSHOT_FREE. In that case, if kernel threads were not 289 * thawed, the preallocation of memory carried out by 290 * hibernation_snapshot() might run into problems (i.e. it 291 * might fail or even deadlock). 292 */ 293 thaw_kernel_threads(); 294 break; 295 296 case SNAPSHOT_PREF_IMAGE_SIZE: 297 image_size = arg; 298 break; 299 300 case SNAPSHOT_GET_IMAGE_SIZE: 301 if (!data->ready) { 302 error = -ENODATA; 303 break; 304 } 305 size = snapshot_get_image_size(); 306 size <<= PAGE_SHIFT; 307 error = put_user(size, (loff_t __user *)arg); 308 break; 309 310 case SNAPSHOT_AVAIL_SWAP_SIZE: 311 size = count_swap_pages(data->swap, 1); 312 size <<= PAGE_SHIFT; 313 error = put_user(size, (loff_t __user *)arg); 314 break; 315 316 case SNAPSHOT_ALLOC_SWAP_PAGE: 317 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 318 error = -ENODEV; 319 break; 320 } 321 offset = alloc_swapdev_block(data->swap); 322 if (offset) { 323 offset <<= PAGE_SHIFT; 324 error = put_user(offset, (loff_t __user *)arg); 325 } else { 326 error = -ENOSPC; 327 } 328 break; 329 330 case SNAPSHOT_FREE_SWAP_PAGES: 331 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 332 error = -ENODEV; 333 break; 334 } 335 free_all_swap_pages(data->swap); 336 break; 337 338 case SNAPSHOT_S2RAM: 339 if (!data->frozen) { 340 error = -EPERM; 341 break; 342 } 343 /* 344 * Tasks are frozen and the notifiers have been called with 345 * PM_HIBERNATION_PREPARE 346 */ 347 error = suspend_devices_and_enter(PM_SUSPEND_MEM); 348 data->ready = false; 349 break; 350 351 case SNAPSHOT_PLATFORM_SUPPORT: 352 data->platform_support = !!arg; 353 break; 354 355 case SNAPSHOT_POWER_OFF: 356 if (data->platform_support) 357 error = hibernation_platform_enter(); 358 break; 359 360 case SNAPSHOT_SET_SWAP_AREA: 361 if (swsusp_swap_in_use()) { 362 error = -EPERM; 363 } else { 364 struct resume_swap_area swap_area; 365 dev_t swdev; 366 367 error = copy_from_user(&swap_area, (void __user *)arg, 368 sizeof(struct resume_swap_area)); 369 if (error) { 370 error = -EFAULT; 371 break; 372 } 373 374 /* 375 * User space encodes device types as two-byte values, 376 * so we need to recode them 377 */ 378 swdev = new_decode_dev(swap_area.dev); 379 if (swdev) { 380 offset = swap_area.offset; 381 data->swap = swap_type_of(swdev, offset, NULL); 382 if (data->swap < 0) 383 error = -ENODEV; 384 } else { 385 data->swap = -1; 386 error = -EINVAL; 387 } 388 } 389 break; 390 391 default: 392 error = -ENOTTY; 393 394 } 395 396 unlock_device_hotplug(); 397 mutex_unlock(&pm_mutex); 398 399 return error; 400 } 401 402 #ifdef CONFIG_COMPAT 403 404 struct compat_resume_swap_area { 405 compat_loff_t offset; 406 u32 dev; 407 } __packed; 408 409 static long 410 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 411 { 412 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t)); 413 414 switch (cmd) { 415 case SNAPSHOT_GET_IMAGE_SIZE: 416 case SNAPSHOT_AVAIL_SWAP_SIZE: 417 case SNAPSHOT_ALLOC_SWAP_PAGE: { 418 compat_loff_t __user *uoffset = compat_ptr(arg); 419 loff_t offset; 420 mm_segment_t old_fs; 421 int err; 422 423 old_fs = get_fs(); 424 set_fs(KERNEL_DS); 425 err = snapshot_ioctl(file, cmd, (unsigned long) &offset); 426 set_fs(old_fs); 427 if (!err && put_user(offset, uoffset)) 428 err = -EFAULT; 429 return err; 430 } 431 432 case SNAPSHOT_CREATE_IMAGE: 433 return snapshot_ioctl(file, cmd, 434 (unsigned long) compat_ptr(arg)); 435 436 case SNAPSHOT_SET_SWAP_AREA: { 437 struct compat_resume_swap_area __user *u_swap_area = 438 compat_ptr(arg); 439 struct resume_swap_area swap_area; 440 mm_segment_t old_fs; 441 int err; 442 443 err = get_user(swap_area.offset, &u_swap_area->offset); 444 err |= get_user(swap_area.dev, &u_swap_area->dev); 445 if (err) 446 return -EFAULT; 447 old_fs = get_fs(); 448 set_fs(KERNEL_DS); 449 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA, 450 (unsigned long) &swap_area); 451 set_fs(old_fs); 452 return err; 453 } 454 455 default: 456 return snapshot_ioctl(file, cmd, arg); 457 } 458 } 459 460 #endif /* CONFIG_COMPAT */ 461 462 static const struct file_operations snapshot_fops = { 463 .open = snapshot_open, 464 .release = snapshot_release, 465 .read = snapshot_read, 466 .write = snapshot_write, 467 .llseek = no_llseek, 468 .unlocked_ioctl = snapshot_ioctl, 469 #ifdef CONFIG_COMPAT 470 .compat_ioctl = snapshot_compat_ioctl, 471 #endif 472 }; 473 474 static struct miscdevice snapshot_device = { 475 .minor = SNAPSHOT_MINOR, 476 .name = "snapshot", 477 .fops = &snapshot_fops, 478 }; 479 480 static int __init snapshot_device_init(void) 481 { 482 return misc_register(&snapshot_device); 483 }; 484 485 device_initcall(snapshot_device_init); 486