kernel/power/user.c

   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 #include <linux/freezer.h>
  26
  27 #include <asm/uaccess.h>
  28
  29 #include "power.h"
  30
  31 #define SNAPSHOT_MINOR  231
  32
  33 static struct snapshot_data {
  34         struct snapshot_handle handle;
  35         int swap;
  36         struct bitmap_page *bitmap;
  37         int mode;
  38         char frozen;
  39         char ready;
  40 } snapshot_state;
  41
  42 static atomic_t device_available = ATOMIC_INIT(1);
  43
  44 static int snapshot_open(struct inode *inode, struct file *filp)
  45 {
  46         struct snapshot_data *data;
  47
  48         if (!atomic_add_unless(&device_available, -1, 0))
  49                 return -EBUSY;
  50
  51         if ((filp->f_flags & O_ACCMODE) == O_RDWR)
  52                 return -ENOSYS;
  53
  54         nonseekable_open(inode, filp);
  55         data = &snapshot_state;
  56         filp->private_data = data;
  57         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  58         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  59                 data->swap = swsusp_resume_device ?
  60                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  61                 data->mode = O_RDONLY;
  62         } else {
  63                 data->swap = -1;
  64                 data->mode = O_WRONLY;
  65         }
  66         data->bitmap = NULL;
  67         data->frozen = 0;
  68         data->ready = 0;
  69
  70         return 0;
  71 }
  72
  73 static int snapshot_release(struct inode *inode, struct file *filp)
  74 {
  75         struct snapshot_data *data;
  76
  77         swsusp_free();
  78         data = filp->private_data;
  79         free_all_swap_pages(data->swap, data->bitmap);
  80         free_bitmap(data->bitmap);
  81         if (data->frozen) {
  82                 mutex_lock(&pm_mutex);
  83                 thaw_processes();
  84                 enable_nonboot_cpus();
  85                 mutex_unlock(&pm_mutex);
  86         }
  87         atomic_inc(&device_available);
  88         return 0;
  89 }
  90
  91 static ssize_t snapshot_read(struct file *filp, char __user *buf,
  92                              size_t count, loff_t *offp)
  93 {
  94         struct snapshot_data *data;
  95         ssize_t res;
  96
  97         data = filp->private_data;
  98         res = snapshot_read_next(&data->handle, count);
  99         if (res > 0) {
 100                 if (copy_to_user(buf, data_of(data->handle), res))
 101                         res = -EFAULT;
 102                 else
 103                         *offp = data->handle.offset;
 104         }
 105         return res;
 106 }
 107
 108 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 109                               size_t count, loff_t *offp)
 110 {
 111         struct snapshot_data *data;
 112         ssize_t res;
 113
 114         data = filp->private_data;
 115         res = snapshot_write_next(&data->handle, count);
 116         if (res > 0) {
 117                 if (copy_from_user(data_of(data->handle), buf, res))
 118                         res = -EFAULT;
 119                 else
 120                         *offp = data->handle.offset;
 121         }
 122         return res;
 123 }
 124
 125 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 126                           unsigned int cmd, unsigned long arg)
 127 {
 128         int error = 0;
 129         struct snapshot_data *data;
 130         loff_t avail;
 131         sector_t offset;
 132
 133         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 134                 return -ENOTTY;
 135         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 136                 return -ENOTTY;
 137         if (!capable(CAP_SYS_ADMIN))
 138                 return -EPERM;
 139
 140         data = filp->private_data;
 141
 142         switch (cmd) {
 143
 144         case SNAPSHOT_FREEZE:
 145                 if (data->frozen)
 146                         break;
 147                 mutex_lock(&pm_mutex);
 148                 error = disable_nonboot_cpus();
 149                 if (!error) {
 150                         error = freeze_processes();
 151                         if (error) {
 152                                 thaw_processes();
 153                                 enable_nonboot_cpus();
 154                                 error = -EBUSY;
 155                         }
 156                 }
 157                 mutex_unlock(&pm_mutex);
 158                 if (!error)
 159                         data->frozen = 1;
 160                 break;
 161
 162         case SNAPSHOT_UNFREEZE:
 163                 if (!data->frozen)
 164                         break;
 165                 mutex_lock(&pm_mutex);
 166                 thaw_processes();
 167                 enable_nonboot_cpus();
 168                 mutex_unlock(&pm_mutex);
 169                 data->frozen = 0;
 170                 break;
 171
 172         case SNAPSHOT_ATOMIC_SNAPSHOT:
 173                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 174                         error = -EPERM;
 175                         break;
 176                 }
 177                 mutex_lock(&pm_mutex);
 178                 /* Free memory before shutting down devices. */
 179                 error = swsusp_shrink_memory();
 180                 if (!error) {
 181                         suspend_console();
 182                         error = device_suspend(PMSG_FREEZE);
 183                         if (!error) {
 184                                 in_suspend = 1;
 185                                 error = swsusp_suspend();
 186                                 device_resume();
 187                         }
 188                         resume_console();
 189                 }
 190                 mutex_unlock(&pm_mutex);
 191                 if (!error)
 192                         error = put_user(in_suspend, (unsigned int __user *)arg);
 193                 if (!error)
 194                         data->ready = 1;
 195                 break;
 196
 197         case SNAPSHOT_ATOMIC_RESTORE:
 198                 snapshot_write_finalize(&data->handle);
 199                 if (data->mode != O_WRONLY || !data->frozen ||
 200                     !snapshot_image_loaded(&data->handle)) {
 201                         error = -EPERM;
 202                         break;
 203                 }
 204                 mutex_lock(&pm_mutex);
 205                 pm_prepare_console();
 206                 suspend_console();
 207                 error = device_suspend(PMSG_PRETHAW);
 208                 if (!error) {
 209                         error = swsusp_resume();
 210                         device_resume();
 211                 }
 212                 resume_console();
 213                 pm_restore_console();
 214                 mutex_unlock(&pm_mutex);
 215                 break;
 216
 217         case SNAPSHOT_FREE:
 218                 swsusp_free();
 219                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 220                 data->ready = 0;
 221                 break;
 222
 223         case SNAPSHOT_SET_IMAGE_SIZE:
 224                 image_size = arg;
 225                 break;
 226
 227         case SNAPSHOT_AVAIL_SWAP:
 228                 avail = count_swap_pages(data->swap, 1);
 229                 avail <<= PAGE_SHIFT;
 230                 error = put_user(avail, (loff_t __user *)arg);
 231                 break;
 232
 233         case SNAPSHOT_GET_SWAP_PAGE:
 234                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 235                         error = -ENODEV;
 236                         break;
 237                 }
 238                 if (!data->bitmap) {
 239                         data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
 240                         if (!data->bitmap) {
 241                                 error = -ENOMEM;
 242                                 break;
 243                         }
 244                 }
 245                 offset = alloc_swapdev_block(data->swap, data->bitmap);
 246                 if (offset) {
 247                         offset <<= PAGE_SHIFT;
 248                         error = put_user(offset, (sector_t __user *)arg);
 249                 } else {
 250                         error = -ENOSPC;
 251                 }
 252                 break;
 253
 254         case SNAPSHOT_FREE_SWAP_PAGES:
 255                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 256                         error = -ENODEV;
 257                         break;
 258                 }
 259                 free_all_swap_pages(data->swap, data->bitmap);
 260                 free_bitmap(data->bitmap);
 261                 data->bitmap = NULL;
 262                 break;
 263
 264         case SNAPSHOT_SET_SWAP_FILE:
 265                 if (!data->bitmap) {
 266                         /*
 267                          * User space encodes device types as two-byte values,
 268                          * so we need to recode them
 269                          */
 270                         if (old_decode_dev(arg)) {
 271                                 data->swap = swap_type_of(old_decode_dev(arg),
 272                                                         0, NULL);
 273                                 if (data->swap < 0)
 274                                         error = -ENODEV;
 275                         } else {
 276                                 data->swap = -1;
 277                                 error = -EINVAL;
 278                         }
 279                 } else {
 280                         error = -EPERM;
 281                 }
 282                 break;
 283
 284         case SNAPSHOT_S2RAM:
 285                 if (!data->frozen) {
 286                         error = -EPERM;
 287                         break;
 288                 }
 289
 290                 if (!mutex_trylock(&pm_mutex)) {
 291                         error = -EBUSY;
 292                         break;
 293                 }
 294
 295                 if (pm_ops->prepare) {
 296                         error = pm_ops->prepare(PM_SUSPEND_MEM);
 297                         if (error)
 298                                 goto OutS3;
 299                 }
 300
 301                 /* Put devices to sleep */
 302                 suspend_console();
 303                 error = device_suspend(PMSG_SUSPEND);
 304                 if (error) {
 305                         printk(KERN_ERR "Failed to suspend some devices.\n");
 306                 } else {
 307                         /* Enter S3, system is already frozen */
 308                         suspend_enter(PM_SUSPEND_MEM);
 309
 310                         /* Wake up devices */
 311                         device_resume();
 312                 }
 313                 resume_console();
 314                 if (pm_ops->finish)
 315                         pm_ops->finish(PM_SUSPEND_MEM);
 316
 317  OutS3:
 318                 mutex_unlock(&pm_mutex);
 319                 break;
 320
 321         case SNAPSHOT_PMOPS:
 322                 switch (arg) {
 323
 324                 case PMOPS_PREPARE:
 325                         if (pm_ops->prepare) {
 326                                 error = pm_ops->prepare(PM_SUSPEND_DISK);
 327                         }
 328                         break;
 329
 330                 case PMOPS_ENTER:
 331                         kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
 332                         error = pm_ops->enter(PM_SUSPEND_DISK);
 333                         break;
 334
 335                 case PMOPS_FINISH:
 336                         if (pm_ops && pm_ops->finish) {
 337                                 pm_ops->finish(PM_SUSPEND_DISK);
 338                         }
 339                         break;
 340
 341                 default:
 342                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 343                         error = -EINVAL;
 344
 345                 }
 346                 break;
 347
 348         case SNAPSHOT_SET_SWAP_AREA:
 349                 if (data->bitmap) {
 350                         error = -EPERM;
 351                 } else {
 352                         struct resume_swap_area swap_area;
 353                         dev_t swdev;
 354
 355                         error = copy_from_user(&swap_area, (void __user *)arg,
 356                                         sizeof(struct resume_swap_area));
 357                         if (error) {
 358                                 error = -EFAULT;
 359                                 break;
 360                         }
 361
 362                         /*
 363                          * User space encodes device types as two-byte values,
 364                          * so we need to recode them
 365                          */
 366                         swdev = old_decode_dev(swap_area.dev);
 367                         if (swdev) {
 368                                 offset = swap_area.offset;
 369                                 data->swap = swap_type_of(swdev, offset, NULL);
 370                                 if (data->swap < 0)
 371                                         error = -ENODEV;
 372                         } else {
 373                                 data->swap = -1;
 374                                 error = -EINVAL;
 375                         }
 376                 }
 377                 break;
 378
 379         default:
 380                 error = -ENOTTY;
 381
 382         }
 383
 384         return error;
 385 }
 386
 387 static const struct file_operations snapshot_fops = {
 388         .open = snapshot_open,
 389         .release = snapshot_release,
 390         .read = snapshot_read,
 391         .write = snapshot_write,
 392         .llseek = no_llseek,
 393         .ioctl = snapshot_ioctl,
 394 };
 395
 396 static struct miscdevice snapshot_device = {
 397         .minor = SNAPSHOT_MINOR,
 398         .name = "snapshot",
 399         .fops = &snapshot_fops,
 400 };
 401
 402 static int __init snapshot_device_init(void)
 403 {
 404         return misc_register(&snapshot_device);
 405 };
 406
 407 device_initcall(snapshot_device_init);