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