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/console.h> 24 #include <linux/cpu.h> 25 26 #include <asm/uaccess.h> 27 28 #include "power.h" 29 30 #define SNAPSHOT_MINOR 231 31 32 static struct snapshot_data { 33 struct snapshot_handle handle; 34 int swap; 35 struct bitmap_page *bitmap; 36 int mode; 37 char frozen; 38 char ready; 39 } snapshot_state; 40 41 static atomic_t device_available = ATOMIC_INIT(1); 42 43 static int snapshot_open(struct inode *inode, struct file *filp) 44 { 45 struct snapshot_data *data; 46 47 if (!atomic_add_unless(&device_available, -1, 0)) 48 return -EBUSY; 49 50 if ((filp->f_flags & O_ACCMODE) == O_RDWR) 51 return -ENOSYS; 52 53 nonseekable_open(inode, filp); 54 data = &snapshot_state; 55 filp->private_data = data; 56 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 57 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) { 58 data->swap = swsusp_resume_device ? 59 swap_type_of(swsusp_resume_device, 0) : -1; 60 data->mode = O_RDONLY; 61 } else { 62 data->swap = -1; 63 data->mode = O_WRONLY; 64 } 65 data->bitmap = NULL; 66 data->frozen = 0; 67 data->ready = 0; 68 69 return 0; 70 } 71 72 static int snapshot_release(struct inode *inode, struct file *filp) 73 { 74 struct snapshot_data *data; 75 76 swsusp_free(); 77 data = filp->private_data; 78 free_all_swap_pages(data->swap, data->bitmap); 79 free_bitmap(data->bitmap); 80 if (data->frozen) { 81 down(&pm_sem); 82 thaw_processes(); 83 enable_nonboot_cpus(); 84 up(&pm_sem); 85 } 86 atomic_inc(&device_available); 87 return 0; 88 } 89 90 static ssize_t snapshot_read(struct file *filp, char __user *buf, 91 size_t count, loff_t *offp) 92 { 93 struct snapshot_data *data; 94 ssize_t res; 95 96 data = filp->private_data; 97 res = snapshot_read_next(&data->handle, count); 98 if (res > 0) { 99 if (copy_to_user(buf, data_of(data->handle), res)) 100 res = -EFAULT; 101 else 102 *offp = data->handle.offset; 103 } 104 return res; 105 } 106 107 static ssize_t snapshot_write(struct file *filp, const char __user *buf, 108 size_t count, loff_t *offp) 109 { 110 struct snapshot_data *data; 111 ssize_t res; 112 113 data = filp->private_data; 114 res = snapshot_write_next(&data->handle, count); 115 if (res > 0) { 116 if (copy_from_user(data_of(data->handle), buf, res)) 117 res = -EFAULT; 118 else 119 *offp = data->handle.offset; 120 } 121 return res; 122 } 123 124 static int snapshot_ioctl(struct inode *inode, struct file *filp, 125 unsigned int cmd, unsigned long arg) 126 { 127 int error = 0; 128 struct snapshot_data *data; 129 loff_t offset, avail; 130 131 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC) 132 return -ENOTTY; 133 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR) 134 return -ENOTTY; 135 if (!capable(CAP_SYS_ADMIN)) 136 return -EPERM; 137 138 data = filp->private_data; 139 140 switch (cmd) { 141 142 case SNAPSHOT_FREEZE: 143 if (data->frozen) 144 break; 145 down(&pm_sem); 146 error = disable_nonboot_cpus(); 147 if (!error) { 148 error = freeze_processes(); 149 if (error) { 150 thaw_processes(); 151 enable_nonboot_cpus(); 152 error = -EBUSY; 153 } 154 } 155 up(&pm_sem); 156 if (!error) 157 data->frozen = 1; 158 break; 159 160 case SNAPSHOT_UNFREEZE: 161 if (!data->frozen) 162 break; 163 down(&pm_sem); 164 thaw_processes(); 165 enable_nonboot_cpus(); 166 up(&pm_sem); 167 data->frozen = 0; 168 break; 169 170 case SNAPSHOT_ATOMIC_SNAPSHOT: 171 if (data->mode != O_RDONLY || !data->frozen || data->ready) { 172 error = -EPERM; 173 break; 174 } 175 down(&pm_sem); 176 /* Free memory before shutting down devices. */ 177 error = swsusp_shrink_memory(); 178 if (!error) { 179 suspend_console(); 180 error = device_suspend(PMSG_FREEZE); 181 if (!error) { 182 in_suspend = 1; 183 error = swsusp_suspend(); 184 device_resume(); 185 } 186 resume_console(); 187 } 188 up(&pm_sem); 189 if (!error) 190 error = put_user(in_suspend, (unsigned int __user *)arg); 191 if (!error) 192 data->ready = 1; 193 break; 194 195 case SNAPSHOT_ATOMIC_RESTORE: 196 if (data->mode != O_WRONLY || !data->frozen || 197 !snapshot_image_loaded(&data->handle)) { 198 error = -EPERM; 199 break; 200 } 201 snapshot_free_unused_memory(&data->handle); 202 down(&pm_sem); 203 pm_prepare_console(); 204 suspend_console(); 205 error = device_suspend(PMSG_PRETHAW); 206 if (!error) { 207 error = swsusp_resume(); 208 device_resume(); 209 } 210 resume_console(); 211 pm_restore_console(); 212 up(&pm_sem); 213 break; 214 215 case SNAPSHOT_FREE: 216 swsusp_free(); 217 memset(&data->handle, 0, sizeof(struct snapshot_handle)); 218 data->ready = 0; 219 break; 220 221 case SNAPSHOT_SET_IMAGE_SIZE: 222 image_size = arg; 223 break; 224 225 case SNAPSHOT_AVAIL_SWAP: 226 avail = count_swap_pages(data->swap, 1); 227 avail <<= PAGE_SHIFT; 228 error = put_user(avail, (loff_t __user *)arg); 229 break; 230 231 case SNAPSHOT_GET_SWAP_PAGE: 232 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 233 error = -ENODEV; 234 break; 235 } 236 if (!data->bitmap) { 237 data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0)); 238 if (!data->bitmap) { 239 error = -ENOMEM; 240 break; 241 } 242 } 243 offset = alloc_swap_page(data->swap, data->bitmap); 244 if (offset) { 245 offset <<= PAGE_SHIFT; 246 error = put_user(offset, (loff_t __user *)arg); 247 } else { 248 error = -ENOSPC; 249 } 250 break; 251 252 case SNAPSHOT_FREE_SWAP_PAGES: 253 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { 254 error = -ENODEV; 255 break; 256 } 257 free_all_swap_pages(data->swap, data->bitmap); 258 free_bitmap(data->bitmap); 259 data->bitmap = NULL; 260 break; 261 262 case SNAPSHOT_SET_SWAP_FILE: 263 if (!data->bitmap) { 264 /* 265 * User space encodes device types as two-byte values, 266 * so we need to recode them 267 */ 268 if (old_decode_dev(arg)) { 269 data->swap = swap_type_of(old_decode_dev(arg), 0); 270 if (data->swap < 0) 271 error = -ENODEV; 272 } else { 273 data->swap = -1; 274 error = -EINVAL; 275 } 276 } else { 277 error = -EPERM; 278 } 279 break; 280 281 case SNAPSHOT_S2RAM: 282 if (!data->frozen) { 283 error = -EPERM; 284 break; 285 } 286 287 if (down_trylock(&pm_sem)) { 288 error = -EBUSY; 289 break; 290 } 291 292 if (pm_ops->prepare) { 293 error = pm_ops->prepare(PM_SUSPEND_MEM); 294 if (error) 295 goto OutS3; 296 } 297 298 /* Put devices to sleep */ 299 suspend_console(); 300 error = device_suspend(PMSG_SUSPEND); 301 if (error) { 302 printk(KERN_ERR "Failed to suspend some devices.\n"); 303 } else { 304 /* Enter S3, system is already frozen */ 305 suspend_enter(PM_SUSPEND_MEM); 306 307 /* Wake up devices */ 308 device_resume(); 309 } 310 resume_console(); 311 if (pm_ops->finish) 312 pm_ops->finish(PM_SUSPEND_MEM); 313 314 OutS3: 315 up(&pm_sem); 316 break; 317 318 case SNAPSHOT_PMOPS: 319 switch (arg) { 320 321 case PMOPS_PREPARE: 322 if (pm_ops->prepare) { 323 error = pm_ops->prepare(PM_SUSPEND_DISK); 324 } 325 break; 326 327 case PMOPS_ENTER: 328 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK); 329 error = pm_ops->enter(PM_SUSPEND_DISK); 330 break; 331 332 case PMOPS_FINISH: 333 if (pm_ops && pm_ops->finish) { 334 pm_ops->finish(PM_SUSPEND_DISK); 335 } 336 break; 337 338 default: 339 printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg); 340 error = -EINVAL; 341 342 } 343 break; 344 345 default: 346 error = -ENOTTY; 347 348 } 349 350 return error; 351 } 352 353 static struct file_operations snapshot_fops = { 354 .open = snapshot_open, 355 .release = snapshot_release, 356 .read = snapshot_read, 357 .write = snapshot_write, 358 .llseek = no_llseek, 359 .ioctl = snapshot_ioctl, 360 }; 361 362 static struct miscdevice snapshot_device = { 363 .minor = SNAPSHOT_MINOR, 364 .name = "snapshot", 365 .fops = &snapshot_fops, 366 }; 367 368 static int __init snapshot_device_init(void) 369 { 370 return misc_register(&snapshot_device); 371 }; 372 373 device_initcall(snapshot_device_init); 374