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