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