1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/kernel/power/user.c 4 * 5 * This file provides the user space interface for software suspend/resume. 6 * 7 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> 8 */ 9 10 #include <linux/suspend.h> 11 #include <linux/reboot.h> 12 #include <linux/string.h> 13 #include <linux/device.h> 14 #include <linux/miscdevice.h> 15 #include <linux/mm.h> 16 #include <linux/swap.h> 17 #include <linux/swapops.h> 18 #include <linux/pm.h> 19 #include <linux/fs.h> 20 #include <linux/compat.h> 21 #include <linux/console.h> 22 #include <linux/cpu.h> 23 #include <linux/freezer.h> 24 25 #include <linux/uaccess.h> 26 27 #include "power.h" 28 29 30 static struct snapshot_data { 31 struct snapshot_handle handle; 32 int swap; 33 int mode; 34 bool frozen; 35 bool ready; 36 bool platform_support; 37 bool free_bitmaps; 38 struct inode *bd_inode; 39 } snapshot_state; 40 41 int is_hibernate_resume_dev(const struct inode *bd_inode) 42 { 43 return hibernation_available() && snapshot_state.bd_inode == bd_inode; 44 } 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 (!hibernate_acquire()) { 57 error = -EBUSY; 58 goto Unlock; 59 } 60 61 if ((filp->f_flags & O_ACCMODE) == O_RDWR) { 62 hibernate_release(); 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 hibernate_release(); 100 101 data->frozen = false; 102 data->ready = false; 103 data->platform_support = false; 104 data->bd_inode = NULL; 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 data->bd_inode = NULL; 121 free_all_swap_pages(data->swap); 122 if (data->frozen) { 123 pm_restore_gfp_mask(); 124 free_basic_memory_bitmaps(); 125 thaw_processes(); 126 } else if (data->free_bitmaps) { 127 free_basic_memory_bitmaps(); 128 } 129 pm_notifier_call_chain(data->mode == O_RDONLY ? 130 PM_POST_HIBERNATION : PM_POST_RESTORE); 131 hibernate_release(); 132 133 unlock_system_sleep(); 134 135 return 0; 136 } 137 138 static ssize_t snapshot_read(struct file *filp, char __user *buf, 139 size_t count, loff_t *offp) 140 { 141 struct snapshot_data *data; 142 ssize_t res; 143 loff_t pg_offp = *offp & ~PAGE_MASK; 144 145 lock_system_sleep(); 146 147 data = filp->private_data; 148 if (!data->ready) { 149 res = -ENODATA; 150 goto Unlock; 151 } 152 if (!pg_offp) { /* on page boundary? */ 153 res = snapshot_read_next(&data->handle); 154 if (res <= 0) 155 goto Unlock; 156 } else { 157 res = PAGE_SIZE - pg_offp; 158 } 159 160 res = simple_read_from_buffer(buf, count, &pg_offp, 161 data_of(data->handle), res); 162 if (res > 0) 163 *offp += res; 164 165 Unlock: 166 unlock_system_sleep(); 167 168 return res; 169 } 170 171 static ssize_t snapshot_write(struct file *filp, const char __user *buf, 172 size_t count, loff_t *offp) 173 { 174 struct snapshot_data *data; 175 ssize_t res; 176 loff_t pg_offp = *offp & ~PAGE_MASK; 177 178 lock_system_sleep(); 179 180 data = filp->private_data; 181 182 if (!pg_offp) { 183 res = snapshot_write_next(&data->handle); 184 if (res <= 0) 185 goto unlock; 186 } else { 187 res = PAGE_SIZE - pg_offp; 188 } 189 190 if (!data_of(data->handle)) { 191 res = -EINVAL; 192 goto unlock; 193 } 194 195 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp, 196 buf, count); 197 if (res > 0) 198 *offp += res; 199 unlock: 200 unlock_system_sleep(); 201 202 return res; 203 } 204 205 struct compat_resume_swap_area { 206 compat_loff_t offset; 207 u32 dev; 208 } __packed; 209 210 static int snapshot_set_swap_area(struct snapshot_data *data, 211 void __user *argp) 212 { 213 struct block_device *bdev; 214 sector_t offset; 215 dev_t swdev; 216 217 if (swsusp_swap_in_use()) 218 return -EPERM; 219 220 if (in_compat_syscall()) { 221 struct compat_resume_swap_area swap_area; 222 223 if (copy_from_user(&swap_area, argp, sizeof(swap_area))) 224 return -EFAULT; 225 swdev = new_decode_dev(swap_area.dev); 226 offset = swap_area.offset; 227 } else { 228 struct resume_swap_area swap_area; 229 230 if (copy_from_user(&swap_area, argp, sizeof(swap_area))) 231 return -EFAULT; 232 swdev = new_decode_dev(swap_area.dev); 233 offset = swap_area.offset; 234 } 235 236 /* 237 * User space encodes device types as two-byte values, 238 * so we need to recode them 239 */ 240 if (!swdev) { 241 data->swap = -1; 242 return -EINVAL; 243 } 244 data->swap = swap_type_of(swdev, offset, &bdev); 245 if (data->swap < 0) 246 return -ENODEV; 247 248 data->bd_inode = bdev->bd_inode; 249 bdput(bdev); 250 return 0; 251 } 252 253 static long snapshot_ioctl(struct file *filp, unsigned int cmd, 254 unsigned long arg) 255 { 256 int error = 0; 257 struct snapshot_data *data; 258 loff_t size; 259 sector_t offset; 260 261 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) 262 return -ENOTTY; 263 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) 264 return -ENOTTY; 265 if (!capable(CAP_SYS_ADMIN)) 266 return -EPERM; 267 268 if (!mutex_trylock(&system_transition_mutex)) 269 return -EBUSY; 270 271 lock_device_hotplug(); 272 data = filp->private_data; 273 274 switch (cmd) { 275 276 case SNAPSHOT_FREEZE: 277 if (data->frozen) 278 break; 279 280 ksys_sync_helper(); 281 282 error = freeze_processes(); 283 if (error) 284 break; 285 286 error = create_basic_memory_bitmaps(); 287 if (error) 288 thaw_processes(); 289 else 290 data->frozen = true; 291 292 break; 293 294 case SNAPSHOT_UNFREEZE: 295 if (!data->frozen || data->ready) 296 break; 297 pm_restore_gfp_mask(); 298 free_basic_memory_bitmaps(); 299 data->free_bitmaps = false; 300 thaw_processes(); 301 data->frozen = false; 302 break; 303 304 case SNAPSHOT_CREATE_IMAGE: 305 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 306 error = -EPERM; 307 break; 308 } 309 pm_restore_gfp_mask(); 310 error = hibernation_snapshot(data->platform_support); 311 if (!error) { 312 error = put_user(in_suspend, (int __user *)arg); 313 data->ready = !freezer_test_done && !error; 314 freezer_test_done = false; 315 } 316 break; 317 318 case SNAPSHOT_ATOMIC_RESTORE: 319 snapshot_write_finalize(&data->handle); 320 if (data->mode != O_WRONLY || !data->frozen || 321 !snapshot_image_loaded(&data->handle)) { 322 error = -EPERM; 323 break; 324 } 325 error = hibernation_restore(data->platform_support); 326 break; 327 328 case SNAPSHOT_FREE: 329 swsusp_free(); 330 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 331 data->ready = false; 332 /* 333 * It is necessary to thaw kernel threads here, because 334 * SNAPSHOT_CREATE_IMAGE may be invoked directly after 335 * SNAPSHOT_FREE. In that case, if kernel threads were not 336 * thawed, the preallocation of memory carried out by 337 * hibernation_snapshot() might run into problems (i.e. it 338 * might fail or even deadlock). 339 */ 340 thaw_kernel_threads(); 341 break; 342 343 case SNAPSHOT_PREF_IMAGE_SIZE: 344 image_size = arg; 345 break; 346 347 case SNAPSHOT_GET_IMAGE_SIZE: 348 if (!data->ready) { 349 error = -ENODATA; 350 break; 351 } 352 size = snapshot_get_image_size(); 353 size <<= PAGE_SHIFT; 354 error = put_user(size, (loff_t __user *)arg); 355 break; 356 357 case SNAPSHOT_AVAIL_SWAP_SIZE: 358 size = count_swap_pages(data->swap, 1); 359 size <<= PAGE_SHIFT; 360 error = put_user(size, (loff_t __user *)arg); 361 break; 362 363 case SNAPSHOT_ALLOC_SWAP_PAGE: 364 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 365 error = -ENODEV; 366 break; 367 } 368 offset = alloc_swapdev_block(data->swap); 369 if (offset) { 370 offset <<= PAGE_SHIFT; 371 error = put_user(offset, (loff_t __user *)arg); 372 } else { 373 error = -ENOSPC; 374 } 375 break; 376 377 case SNAPSHOT_FREE_SWAP_PAGES: 378 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 379 error = -ENODEV; 380 break; 381 } 382 free_all_swap_pages(data->swap); 383 break; 384 385 case SNAPSHOT_S2RAM: 386 if (!data->frozen) { 387 error = -EPERM; 388 break; 389 } 390 /* 391 * Tasks are frozen and the notifiers have been called with 392 * PM_HIBERNATION_PREPARE 393 */ 394 error = suspend_devices_and_enter(PM_SUSPEND_MEM); 395 data->ready = false; 396 break; 397 398 case SNAPSHOT_PLATFORM_SUPPORT: 399 data->platform_support = !!arg; 400 break; 401 402 case SNAPSHOT_POWER_OFF: 403 if (data->platform_support) 404 error = hibernation_platform_enter(); 405 break; 406 407 case SNAPSHOT_SET_SWAP_AREA: 408 error = snapshot_set_swap_area(data, (void __user *)arg); 409 break; 410 411 default: 412 error = -ENOTTY; 413 414 } 415 416 unlock_device_hotplug(); 417 mutex_unlock(&system_transition_mutex); 418 419 return error; 420 } 421 422 #ifdef CONFIG_COMPAT 423 static long 424 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 425 { 426 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t)); 427 428 switch (cmd) { 429 case SNAPSHOT_GET_IMAGE_SIZE: 430 case SNAPSHOT_AVAIL_SWAP_SIZE: 431 case SNAPSHOT_ALLOC_SWAP_PAGE: 432 case SNAPSHOT_CREATE_IMAGE: 433 case SNAPSHOT_SET_SWAP_AREA: 434 return snapshot_ioctl(file, cmd, 435 (unsigned long) compat_ptr(arg)); 436 default: 437 return snapshot_ioctl(file, cmd, arg); 438 } 439 } 440 #endif /* CONFIG_COMPAT */ 441 442 static const struct file_operations snapshot_fops = { 443 .open = snapshot_open, 444 .release = snapshot_release, 445 .read = snapshot_read, 446 .write = snapshot_write, 447 .llseek = no_llseek, 448 .unlocked_ioctl = snapshot_ioctl, 449 #ifdef CONFIG_COMPAT 450 .compat_ioctl = snapshot_compat_ioctl, 451 #endif 452 }; 453 454 static struct miscdevice snapshot_device = { 455 .minor = SNAPSHOT_MINOR, 456 .name = "snapshot", 457 .fops = &snapshot_fops, 458 }; 459 460 static int __init snapshot_device_init(void) 461 { 462 return misc_register(&snapshot_device); 463 }; 464 465 device_initcall(snapshot_device_init); 466