kernel/power/hibernate.c

   1 /*
   2  * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   7  * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   8  * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
   9  *
  10  * This file is released under the GPLv2.
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/suspend.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/reboot.h>
  17 #include <linux/string.h>
  18 #include <linux/device.h>
  19 #include <linux/async.h>
  20 #include <linux/delay.h>
  21 #include <linux/fs.h>
  22 #include <linux/mount.h>
  23 #include <linux/pm.h>
  24 #include <linux/console.h>
  25 #include <linux/cpu.h>
  26 #include <linux/freezer.h>
  27 #include <linux/gfp.h>
  28 #include <linux/syscore_ops.h>
  29 #include <linux/ctype.h>
  30 #include <linux/genhd.h>
  31 #include <trace/events/power.h>
  32
  33 #include "power.h"
  34
  35
  36 static int nocompress;
  37 static int noresume;
  38 static int resume_wait;
  39 static unsigned int resume_delay;
  40 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  41 dev_t swsusp_resume_device;
  42 sector_t swsusp_resume_block;
  43 __visible int in_suspend __nosavedata;
  44
  45 enum {
  46         HIBERNATION_INVALID,
  47         HIBERNATION_PLATFORM,
  48         HIBERNATION_SHUTDOWN,
  49         HIBERNATION_REBOOT,
  50 #ifdef CONFIG_SUSPEND
  51         HIBERNATION_SUSPEND,
  52 #endif
  53         /* keep last */
  54         __HIBERNATION_AFTER_LAST
  55 };
  56 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  57 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  58
  59 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  60
  61 bool freezer_test_done;
  62
  63 static const struct platform_hibernation_ops *hibernation_ops;
  64
  65 /**
  66  * hibernation_set_ops - Set the global hibernate operations.
  67  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  68  */
  69 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  70 {
  71         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  72             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  73             && ops->restore_cleanup && ops->leave)) {
  74                 WARN_ON(1);
  75                 return;
  76         }
  77         lock_system_sleep();
  78         hibernation_ops = ops;
  79         if (ops)
  80                 hibernation_mode = HIBERNATION_PLATFORM;
  81         else if (hibernation_mode == HIBERNATION_PLATFORM)
  82                 hibernation_mode = HIBERNATION_SHUTDOWN;
  83
  84         unlock_system_sleep();
  85 }
  86 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  87
  88 static bool entering_platform_hibernation;
  89
  90 bool system_entering_hibernation(void)
  91 {
  92         return entering_platform_hibernation;
  93 }
  94 EXPORT_SYMBOL(system_entering_hibernation);
  95
  96 #ifdef CONFIG_PM_DEBUG
  97 static void hibernation_debug_sleep(void)
  98 {
  99         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 100         mdelay(5000);
 101 }
 102
 103 static int hibernation_test(int level)
 104 {
 105         if (pm_test_level == level) {
 106                 hibernation_debug_sleep();
 107                 return 1;
 108         }
 109         return 0;
 110 }
 111 #else /* !CONFIG_PM_DEBUG */
 112 static int hibernation_test(int level) { return 0; }
 113 #endif /* !CONFIG_PM_DEBUG */
 114
 115 /**
 116  * platform_begin - Call platform to start hibernation.
 117  * @platform_mode: Whether or not to use the platform driver.
 118  */
 119 static int platform_begin(int platform_mode)
 120 {
 121         return (platform_mode && hibernation_ops) ?
 122                 hibernation_ops->begin() : 0;
 123 }
 124
 125 /**
 126  * platform_end - Call platform to finish transition to the working state.
 127  * @platform_mode: Whether or not to use the platform driver.
 128  */
 129 static void platform_end(int platform_mode)
 130 {
 131         if (platform_mode && hibernation_ops)
 132                 hibernation_ops->end();
 133 }
 134
 135 /**
 136  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 137  * @platform_mode: Whether or not to use the platform driver.
 138  *
 139  * Use the platform driver to prepare the system for creating a hibernate image,
 140  * if so configured, and return an error code if that fails.
 141  */
 142
 143 static int platform_pre_snapshot(int platform_mode)
 144 {
 145         return (platform_mode && hibernation_ops) ?
 146                 hibernation_ops->pre_snapshot() : 0;
 147 }
 148
 149 /**
 150  * platform_leave - Call platform to prepare a transition to the working state.
 151  * @platform_mode: Whether or not to use the platform driver.
 152  *
 153  * Use the platform driver prepare to prepare the machine for switching to the
 154  * normal mode of operation.
 155  *
 156  * This routine is called on one CPU with interrupts disabled.
 157  */
 158 static void platform_leave(int platform_mode)
 159 {
 160         if (platform_mode && hibernation_ops)
 161                 hibernation_ops->leave();
 162 }
 163
 164 /**
 165  * platform_finish - Call platform to switch the system to the working state.
 166  * @platform_mode: Whether or not to use the platform driver.
 167  *
 168  * Use the platform driver to switch the machine to the normal mode of
 169  * operation.
 170  *
 171  * This routine must be called after platform_prepare().
 172  */
 173 static void platform_finish(int platform_mode)
 174 {
 175         if (platform_mode && hibernation_ops)
 176                 hibernation_ops->finish();
 177 }
 178
 179 /**
 180  * platform_pre_restore - Prepare for hibernate image restoration.
 181  * @platform_mode: Whether or not to use the platform driver.
 182  *
 183  * Use the platform driver to prepare the system for resume from a hibernation
 184  * image.
 185  *
 186  * If the restore fails after this function has been called,
 187  * platform_restore_cleanup() must be called.
 188  */
 189 static int platform_pre_restore(int platform_mode)
 190 {
 191         return (platform_mode && hibernation_ops) ?
 192                 hibernation_ops->pre_restore() : 0;
 193 }
 194
 195 /**
 196  * platform_restore_cleanup - Switch to the working state after failing restore.
 197  * @platform_mode: Whether or not to use the platform driver.
 198  *
 199  * Use the platform driver to switch the system to the normal mode of operation
 200  * after a failing restore.
 201  *
 202  * If platform_pre_restore() has been called before the failing restore, this
 203  * function must be called too, regardless of the result of
 204  * platform_pre_restore().
 205  */
 206 static void platform_restore_cleanup(int platform_mode)
 207 {
 208         if (platform_mode && hibernation_ops)
 209                 hibernation_ops->restore_cleanup();
 210 }
 211
 212 /**
 213  * platform_recover - Recover from a failure to suspend devices.
 214  * @platform_mode: Whether or not to use the platform driver.
 215  */
 216 static void platform_recover(int platform_mode)
 217 {
 218         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 219                 hibernation_ops->recover();
 220 }
 221
 222 /**
 223  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 224  * @start: Starting event.
 225  * @stop: Final event.
 226  * @nr_pages: Number of memory pages processed between @start and @stop.
 227  * @msg: Additional diagnostic message to print.
 228  */
 229 void swsusp_show_speed(struct timeval *start, struct timeval *stop,
 230                         unsigned nr_pages, char *msg)
 231 {
 232         u64 elapsed_centisecs64;
 233         unsigned int centisecs;
 234         unsigned int k;
 235         unsigned int kps;
 236
 237         elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
 238         /*
 239          * If "(s64)elapsed_centisecs64 < 0", it will print long elapsed time,
 240          * it is obvious enough for what went wrong.
 241          */
 242         do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 243         centisecs = elapsed_centisecs64;
 244         if (centisecs == 0)
 245                 centisecs = 1;  /* avoid div-by-zero */
 246         k = nr_pages * (PAGE_SIZE / 1024);
 247         kps = (k * 100) / centisecs;
 248         printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 249                         msg, k,
 250                         centisecs / 100, centisecs % 100,
 251                         kps / 1000, (kps % 1000) / 10);
 252 }
 253
 254 /**
 255  * create_image - Create a hibernation image.
 256  * @platform_mode: Whether or not to use the platform driver.
 257  *
 258  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 259  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 260  *
 261  * Control reappears in this routine after the subsequent restore.
 262  */
 263 static int create_image(int platform_mode)
 264 {
 265         int error;
 266
 267         error = dpm_suspend_end(PMSG_FREEZE);
 268         if (error) {
 269                 printk(KERN_ERR "PM: Some devices failed to power down, "
 270                         "aborting hibernation\n");
 271                 return error;
 272         }
 273
 274         error = platform_pre_snapshot(platform_mode);
 275         if (error || hibernation_test(TEST_PLATFORM))
 276                 goto Platform_finish;
 277
 278         error = disable_nonboot_cpus();
 279         if (error || hibernation_test(TEST_CPUS))
 280                 goto Enable_cpus;
 281
 282         local_irq_disable();
 283
 284         error = syscore_suspend();
 285         if (error) {
 286                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 287                         "aborting hibernation\n");
 288                 goto Enable_irqs;
 289         }
 290
 291         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 292                 goto Power_up;
 293
 294         in_suspend = 1;
 295         save_processor_state();
 296         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 297         error = swsusp_arch_suspend();
 298         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 299         if (error)
 300                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 301                         error);
 302         /* Restore control flow magically appears here */
 303         restore_processor_state();
 304         if (!in_suspend)
 305                 events_check_enabled = false;
 306
 307         platform_leave(platform_mode);
 308
 309  Power_up:
 310         syscore_resume();
 311
 312  Enable_irqs:
 313         local_irq_enable();
 314
 315  Enable_cpus:
 316         enable_nonboot_cpus();
 317
 318  Platform_finish:
 319         platform_finish(platform_mode);
 320
 321         dpm_resume_start(in_suspend ?
 322                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 323
 324         return error;
 325 }
 326
 327 /**
 328  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 329  * @platform_mode: If set, use platform driver to prepare for the transition.
 330  *
 331  * This routine must be called with pm_mutex held.
 332  */
 333 int hibernation_snapshot(int platform_mode)
 334 {
 335         pm_message_t msg;
 336         int error;
 337
 338         error = platform_begin(platform_mode);
 339         if (error)
 340                 goto Close;
 341
 342         /* Preallocate image memory before shutting down devices. */
 343         error = hibernate_preallocate_memory();
 344         if (error)
 345                 goto Close;
 346
 347         error = freeze_kernel_threads();
 348         if (error)
 349                 goto Cleanup;
 350
 351         if (hibernation_test(TEST_FREEZER)) {
 352
 353                 /*
 354                  * Indicate to the caller that we are returning due to a
 355                  * successful freezer test.
 356                  */
 357                 freezer_test_done = true;
 358                 goto Thaw;
 359         }
 360
 361         error = dpm_prepare(PMSG_FREEZE);
 362         if (error) {
 363                 dpm_complete(PMSG_RECOVER);
 364                 goto Thaw;
 365         }
 366
 367         suspend_console();
 368         ftrace_stop();
 369         pm_restrict_gfp_mask();
 370
 371         error = dpm_suspend(PMSG_FREEZE);
 372
 373         if (error || hibernation_test(TEST_DEVICES))
 374                 platform_recover(platform_mode);
 375         else
 376                 error = create_image(platform_mode);
 377
 378         /*
 379          * In the case that we call create_image() above, the control
 380          * returns here (1) after the image has been created or the
 381          * image creation has failed and (2) after a successful restore.
 382          */
 383
 384         /* We may need to release the preallocated image pages here. */
 385         if (error || !in_suspend)
 386                 swsusp_free();
 387
 388         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 389         dpm_resume(msg);
 390
 391         if (error || !in_suspend)
 392                 pm_restore_gfp_mask();
 393
 394         ftrace_start();
 395         resume_console();
 396         dpm_complete(msg);
 397
 398  Close:
 399         platform_end(platform_mode);
 400         return error;
 401
 402  Thaw:
 403         thaw_kernel_threads();
 404  Cleanup:
 405         swsusp_free();
 406         goto Close;
 407 }
 408
 409 /**
 410  * resume_target_kernel - Restore system state from a hibernation image.
 411  * @platform_mode: Whether or not to use the platform driver.
 412  *
 413  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 414  * contents of highmem that have not been restored yet from the image and run
 415  * the low-level code that will restore the remaining contents of memory and
 416  * switch to the just restored target kernel.
 417  */
 418 static int resume_target_kernel(bool platform_mode)
 419 {
 420         int error;
 421
 422         error = dpm_suspend_end(PMSG_QUIESCE);
 423         if (error) {
 424                 printk(KERN_ERR "PM: Some devices failed to power down, "
 425                         "aborting resume\n");
 426                 return error;
 427         }
 428
 429         error = platform_pre_restore(platform_mode);
 430         if (error)
 431                 goto Cleanup;
 432
 433         error = disable_nonboot_cpus();
 434         if (error)
 435                 goto Enable_cpus;
 436
 437         local_irq_disable();
 438
 439         error = syscore_suspend();
 440         if (error)
 441                 goto Enable_irqs;
 442
 443         save_processor_state();
 444         error = restore_highmem();
 445         if (!error) {
 446                 error = swsusp_arch_resume();
 447                 /*
 448                  * The code below is only ever reached in case of a failure.
 449                  * Otherwise, execution continues at the place where
 450                  * swsusp_arch_suspend() was called.
 451                  */
 452                 BUG_ON(!error);
 453                 /*
 454                  * This call to restore_highmem() reverts the changes made by
 455                  * the previous one.
 456                  */
 457                 restore_highmem();
 458         }
 459         /*
 460          * The only reason why swsusp_arch_resume() can fail is memory being
 461          * very tight, so we have to free it as soon as we can to avoid
 462          * subsequent failures.
 463          */
 464         swsusp_free();
 465         restore_processor_state();
 466         touch_softlockup_watchdog();
 467
 468         syscore_resume();
 469
 470  Enable_irqs:
 471         local_irq_enable();
 472
 473  Enable_cpus:
 474         enable_nonboot_cpus();
 475
 476  Cleanup:
 477         platform_restore_cleanup(platform_mode);
 478
 479         dpm_resume_start(PMSG_RECOVER);
 480
 481         return error;
 482 }
 483
 484 /**
 485  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 486  * @platform_mode: If set, use platform driver to prepare for the transition.
 487  *
 488  * This routine must be called with pm_mutex held.  If it is successful, control
 489  * reappears in the restored target kernel in hibernation_snapshot().
 490  */
 491 int hibernation_restore(int platform_mode)
 492 {
 493         int error;
 494
 495         pm_prepare_console();
 496         suspend_console();
 497         ftrace_stop();
 498         pm_restrict_gfp_mask();
 499         error = dpm_suspend_start(PMSG_QUIESCE);
 500         if (!error) {
 501                 error = resume_target_kernel(platform_mode);
 502                 dpm_resume_end(PMSG_RECOVER);
 503         }
 504         pm_restore_gfp_mask();
 505         ftrace_start();
 506         resume_console();
 507         pm_restore_console();
 508         return error;
 509 }
 510
 511 /**
 512  * hibernation_platform_enter - Power off the system using the platform driver.
 513  */
 514 int hibernation_platform_enter(void)
 515 {
 516         int error;
 517
 518         if (!hibernation_ops)
 519                 return -ENOSYS;
 520
 521         /*
 522          * We have cancelled the power transition by running
 523          * hibernation_ops->finish() before saving the image, so we should let
 524          * the firmware know that we're going to enter the sleep state after all
 525          */
 526         error = hibernation_ops->begin();
 527         if (error)
 528                 goto Close;
 529
 530         entering_platform_hibernation = true;
 531         suspend_console();
 532         ftrace_stop();
 533         error = dpm_suspend_start(PMSG_HIBERNATE);
 534         if (error) {
 535                 if (hibernation_ops->recover)
 536                         hibernation_ops->recover();
 537                 goto Resume_devices;
 538         }
 539
 540         error = dpm_suspend_end(PMSG_HIBERNATE);
 541         if (error)
 542                 goto Resume_devices;
 543
 544         error = hibernation_ops->prepare();
 545         if (error)
 546                 goto Platform_finish;
 547
 548         error = disable_nonboot_cpus();
 549         if (error)
 550                 goto Platform_finish;
 551
 552         local_irq_disable();
 553         syscore_suspend();
 554         if (pm_wakeup_pending()) {
 555                 error = -EAGAIN;
 556                 goto Power_up;
 557         }
 558
 559         hibernation_ops->enter();
 560         /* We should never get here */
 561         while (1);
 562
 563  Power_up:
 564         syscore_resume();
 565         local_irq_enable();
 566         enable_nonboot_cpus();
 567
 568  Platform_finish:
 569         hibernation_ops->finish();
 570
 571         dpm_resume_start(PMSG_RESTORE);
 572
 573  Resume_devices:
 574         entering_platform_hibernation = false;
 575         dpm_resume_end(PMSG_RESTORE);
 576         ftrace_start();
 577         resume_console();
 578
 579  Close:
 580         hibernation_ops->end();
 581
 582         return error;
 583 }
 584
 585 /**
 586  * power_down - Shut the machine down for hibernation.
 587  *
 588  * Use the platform driver, if configured, to put the system into the sleep
 589  * state corresponding to hibernation, or try to power it off or reboot,
 590  * depending on the value of hibernation_mode.
 591  */
 592 static void power_down(void)
 593 {
 594 #ifdef CONFIG_SUSPEND
 595         int error;
 596 #endif
 597
 598         switch (hibernation_mode) {
 599         case HIBERNATION_REBOOT:
 600                 kernel_restart(NULL);
 601                 break;
 602         case HIBERNATION_PLATFORM:
 603                 hibernation_platform_enter();
 604         case HIBERNATION_SHUTDOWN:
 605                 if (pm_power_off)
 606                         kernel_power_off();
 607                 break;
 608 #ifdef CONFIG_SUSPEND
 609         case HIBERNATION_SUSPEND:
 610                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 611                 if (error) {
 612                         if (hibernation_ops)
 613                                 hibernation_mode = HIBERNATION_PLATFORM;
 614                         else
 615                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 616                         power_down();
 617                 }
 618                 /*
 619                  * Restore swap signature.
 620                  */
 621                 error = swsusp_unmark();
 622                 if (error)
 623                         printk(KERN_ERR "PM: Swap will be unusable! "
 624                                         "Try swapon -a.\n");
 625                 return;
 626 #endif
 627         }
 628         kernel_halt();
 629         /*
 630          * Valid image is on the disk, if we continue we risk serious data
 631          * corruption after resume.
 632          */
 633         printk(KERN_CRIT "PM: Please power down manually\n");
 634         while (1)
 635                 cpu_relax();
 636 }
 637
 638 /**
 639  * hibernate - Carry out system hibernation, including saving the image.
 640  */
 641 int hibernate(void)
 642 {
 643         int error;
 644
 645         lock_system_sleep();
 646         /* The snapshot device should not be opened while we're running */
 647         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 648                 error = -EBUSY;
 649                 goto Unlock;
 650         }
 651
 652         pm_prepare_console();
 653         error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 654         if (error)
 655                 goto Exit;
 656
 657         printk(KERN_INFO "PM: Syncing filesystems ... ");
 658         sys_sync();
 659         printk("done.\n");
 660
 661         error = freeze_processes();
 662         if (error)
 663                 goto Exit;
 664
 665         lock_device_hotplug();
 666         /* Allocate memory management structures */
 667         error = create_basic_memory_bitmaps();
 668         if (error)
 669                 goto Thaw;
 670
 671         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 672         if (error || freezer_test_done)
 673                 goto Free_bitmaps;
 674
 675         if (in_suspend) {
 676                 unsigned int flags = 0;
 677
 678                 if (hibernation_mode == HIBERNATION_PLATFORM)
 679                         flags |= SF_PLATFORM_MODE;
 680                 if (nocompress)
 681                         flags |= SF_NOCOMPRESS_MODE;
 682                 else
 683                         flags |= SF_CRC32_MODE;
 684
 685                 pr_debug("PM: writing image.\n");
 686                 error = swsusp_write(flags);
 687                 swsusp_free();
 688                 if (!error)
 689                         power_down();
 690                 in_suspend = 0;
 691                 pm_restore_gfp_mask();
 692         } else {
 693                 pr_debug("PM: Image restored successfully.\n");
 694         }
 695
 696  Free_bitmaps:
 697         free_basic_memory_bitmaps();
 698  Thaw:
 699         unlock_device_hotplug();
 700         thaw_processes();
 701
 702         /* Don't bother checking whether freezer_test_done is true */
 703         freezer_test_done = false;
 704  Exit:
 705         pm_notifier_call_chain(PM_POST_HIBERNATION);
 706         pm_restore_console();
 707         atomic_inc(&snapshot_device_available);
 708  Unlock:
 709         unlock_system_sleep();
 710         return error;
 711 }
 712
 713
 714 /**
 715  * software_resume - Resume from a saved hibernation image.
 716  *
 717  * This routine is called as a late initcall, when all devices have been
 718  * discovered and initialized already.
 719  *
 720  * The image reading code is called to see if there is a hibernation image
 721  * available for reading.  If that is the case, devices are quiesced and the
 722  * contents of memory is restored from the saved image.
 723  *
 724  * If this is successful, control reappears in the restored target kernel in
 725  * hibernation_snaphot() which returns to hibernate().  Otherwise, the routine
 726  * attempts to recover gracefully and make the kernel return to the normal mode
 727  * of operation.
 728  */
 729 static int software_resume(void)
 730 {
 731         int error;
 732         unsigned int flags;
 733
 734         /*
 735          * If the user said "noresume".. bail out early.
 736          */
 737         if (noresume)
 738                 return 0;
 739
 740         /*
 741          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 742          * is configured into the kernel. Since the regular hibernate
 743          * trigger path is via sysfs which takes a buffer mutex before
 744          * calling hibernate functions (which take pm_mutex) this can
 745          * cause lockdep to complain about a possible ABBA deadlock
 746          * which cannot happen since we're in the boot code here and
 747          * sysfs can't be invoked yet. Therefore, we use a subclass
 748          * here to avoid lockdep complaining.
 749          */
 750         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 751
 752         if (swsusp_resume_device)
 753                 goto Check_image;
 754
 755         if (!strlen(resume_file)) {
 756                 error = -ENOENT;
 757                 goto Unlock;
 758         }
 759
 760         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 761
 762         if (resume_delay) {
 763                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 764                         resume_delay);
 765                 ssleep(resume_delay);
 766         }
 767
 768         /* Check if the device is there */
 769         swsusp_resume_device = name_to_dev_t(resume_file);
 770
 771         /*
 772          * name_to_dev_t is ineffective to verify parition if resume_file is in
 773          * integer format. (e.g. major:minor)
 774          */
 775         if (isdigit(resume_file[0]) && resume_wait) {
 776                 int partno;
 777                 while (!get_gendisk(swsusp_resume_device, &partno))
 778                         msleep(10);
 779         }
 780
 781         if (!swsusp_resume_device) {
 782                 /*
 783                  * Some device discovery might still be in progress; we need
 784                  * to wait for this to finish.
 785                  */
 786                 wait_for_device_probe();
 787
 788                 if (resume_wait) {
 789                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 790                                 msleep(10);
 791                         async_synchronize_full();
 792                 }
 793
 794                 swsusp_resume_device = name_to_dev_t(resume_file);
 795                 if (!swsusp_resume_device) {
 796                         error = -ENODEV;
 797                         goto Unlock;
 798                 }
 799         }
 800
 801  Check_image:
 802         pr_debug("PM: Hibernation image partition %d:%d present\n",
 803                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 804
 805         pr_debug("PM: Looking for hibernation image.\n");
 806         error = swsusp_check();
 807         if (error)
 808                 goto Unlock;
 809
 810         /* The snapshot device should not be opened while we're running */
 811         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 812                 error = -EBUSY;
 813                 swsusp_close(FMODE_READ);
 814                 goto Unlock;
 815         }
 816
 817         pm_prepare_console();
 818         error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 819         if (error)
 820                 goto Close_Finish;
 821
 822         pr_debug("PM: Preparing processes for restore.\n");
 823         error = freeze_processes();
 824         if (error)
 825                 goto Close_Finish;
 826
 827         pr_debug("PM: Loading hibernation image.\n");
 828
 829         lock_device_hotplug();
 830         error = create_basic_memory_bitmaps();
 831         if (error)
 832                 goto Thaw;
 833
 834         error = swsusp_read(&flags);
 835         swsusp_close(FMODE_READ);
 836         if (!error)
 837                 hibernation_restore(flags & SF_PLATFORM_MODE);
 838
 839         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 840         swsusp_free();
 841         free_basic_memory_bitmaps();
 842  Thaw:
 843         unlock_device_hotplug();
 844         thaw_processes();
 845  Finish:
 846         pm_notifier_call_chain(PM_POST_RESTORE);
 847         pm_restore_console();
 848         atomic_inc(&snapshot_device_available);
 849         /* For success case, the suspend path will release the lock */
 850  Unlock:
 851         mutex_unlock(&pm_mutex);
 852         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 853         return error;
 854  Close_Finish:
 855         swsusp_close(FMODE_READ);
 856         goto Finish;
 857 }
 858
 859 late_initcall_sync(software_resume);
 860
 861
 862 static const char * const hibernation_modes[] = {
 863         [HIBERNATION_PLATFORM]  = "platform",
 864         [HIBERNATION_SHUTDOWN]  = "shutdown",
 865         [HIBERNATION_REBOOT]    = "reboot",
 866 #ifdef CONFIG_SUSPEND
 867         [HIBERNATION_SUSPEND]   = "suspend",
 868 #endif
 869 };
 870
 871 /*
 872  * /sys/power/disk - Control hibernation mode.
 873  *
 874  * Hibernation can be handled in several ways.  There are a few different ways
 875  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 876  * or other hibernation_ops), powering it off or rebooting it (for testing
 877  * mostly).
 878  *
 879  * The sysfs file /sys/power/disk provides an interface for selecting the
 880  * hibernation mode to use.  Reading from this file causes the available modes
 881  * to be printed.  There are 3 modes that can be supported:
 882  *
 883  *      'platform'
 884  *      'shutdown'
 885  *      'reboot'
 886  *
 887  * If a platform hibernation driver is in use, 'platform' will be supported
 888  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 889  * The selected option (i.e. the one corresponding to the current value of
 890  * hibernation_mode) is enclosed by a square bracket.
 891  *
 892  * To select a given hibernation mode it is necessary to write the mode's
 893  * string representation (as returned by reading from /sys/power/disk) back
 894  * into /sys/power/disk.
 895  */
 896
 897 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 898                          char *buf)
 899 {
 900         int i;
 901         char *start = buf;
 902
 903         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 904                 if (!hibernation_modes[i])
 905                         continue;
 906                 switch (i) {
 907                 case HIBERNATION_SHUTDOWN:
 908                 case HIBERNATION_REBOOT:
 909 #ifdef CONFIG_SUSPEND
 910                 case HIBERNATION_SUSPEND:
 911 #endif
 912                         break;
 913                 case HIBERNATION_PLATFORM:
 914                         if (hibernation_ops)
 915                                 break;
 916                         /* not a valid mode, continue with loop */
 917                         continue;
 918                 }
 919                 if (i == hibernation_mode)
 920                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 921                 else
 922                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 923         }
 924         buf += sprintf(buf, "\n");
 925         return buf-start;
 926 }
 927
 928 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 929                           const char *buf, size_t n)
 930 {
 931         int error = 0;
 932         int i;
 933         int len;
 934         char *p;
 935         int mode = HIBERNATION_INVALID;
 936
 937         p = memchr(buf, '\n', n);
 938         len = p ? p - buf : n;
 939
 940         lock_system_sleep();
 941         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 942                 if (len == strlen(hibernation_modes[i])
 943                     && !strncmp(buf, hibernation_modes[i], len)) {
 944                         mode = i;
 945                         break;
 946                 }
 947         }
 948         if (mode != HIBERNATION_INVALID) {
 949                 switch (mode) {
 950                 case HIBERNATION_SHUTDOWN:
 951                 case HIBERNATION_REBOOT:
 952 #ifdef CONFIG_SUSPEND
 953                 case HIBERNATION_SUSPEND:
 954 #endif
 955                         hibernation_mode = mode;
 956                         break;
 957                 case HIBERNATION_PLATFORM:
 958                         if (hibernation_ops)
 959                                 hibernation_mode = mode;
 960                         else
 961                                 error = -EINVAL;
 962                 }
 963         } else
 964                 error = -EINVAL;
 965
 966         if (!error)
 967                 pr_debug("PM: Hibernation mode set to '%s'\n",
 968                          hibernation_modes[mode]);
 969         unlock_system_sleep();
 970         return error ? error : n;
 971 }
 972
 973 power_attr(disk);
 974
 975 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
 976                            char *buf)
 977 {
 978         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 979                        MINOR(swsusp_resume_device));
 980 }
 981
 982 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 983                             const char *buf, size_t n)
 984 {
 985         dev_t res;
 986         int len = n;
 987         char *name;
 988
 989         if (len && buf[len-1] == '\n')
 990                 len--;
 991         name = kstrndup(buf, len, GFP_KERNEL);
 992         if (!name)
 993                 return -ENOMEM;
 994
 995         res = name_to_dev_t(name);
 996         kfree(name);
 997         if (!res)
 998                 return -EINVAL;
 999
1000         lock_system_sleep();
1001         swsusp_resume_device = res;
1002         unlock_system_sleep();
1003         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1004         noresume = 0;
1005         software_resume();
1006         return n;
1007 }
1008
1009 power_attr(resume);
1010
1011 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1012                                char *buf)
1013 {
1014         return sprintf(buf, "%lu\n", image_size);
1015 }
1016
1017 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1018                                 const char *buf, size_t n)
1019 {
1020         unsigned long size;
1021
1022         if (sscanf(buf, "%lu", &size) == 1) {
1023                 image_size = size;
1024                 return n;
1025         }
1026
1027         return -EINVAL;
1028 }
1029
1030 power_attr(image_size);
1031
1032 static ssize_t reserved_size_show(struct kobject *kobj,
1033                                   struct kobj_attribute *attr, char *buf)
1034 {
1035         return sprintf(buf, "%lu\n", reserved_size);
1036 }
1037
1038 static ssize_t reserved_size_store(struct kobject *kobj,
1039                                    struct kobj_attribute *attr,
1040                                    const char *buf, size_t n)
1041 {
1042         unsigned long size;
1043
1044         if (sscanf(buf, "%lu", &size) == 1) {
1045                 reserved_size = size;
1046                 return n;
1047         }
1048
1049         return -EINVAL;
1050 }
1051
1052 power_attr(reserved_size);
1053
1054 static struct attribute * g[] = {
1055         &disk_attr.attr,
1056         &resume_attr.attr,
1057         &image_size_attr.attr,
1058         &reserved_size_attr.attr,
1059         NULL,
1060 };
1061
1062
1063 static struct attribute_group attr_group = {
1064         .attrs = g,
1065 };
1066
1067
1068 static int __init pm_disk_init(void)
1069 {
1070         return sysfs_create_group(power_kobj, &attr_group);
1071 }
1072
1073 core_initcall(pm_disk_init);
1074
1075
1076 static int __init resume_setup(char *str)
1077 {
1078         if (noresume)
1079                 return 1;
1080
1081         strncpy( resume_file, str, 255 );
1082         return 1;
1083 }
1084
1085 static int __init resume_offset_setup(char *str)
1086 {
1087         unsigned long long offset;
1088
1089         if (noresume)
1090                 return 1;
1091
1092         if (sscanf(str, "%llu", &offset) == 1)
1093                 swsusp_resume_block = offset;
1094
1095         return 1;
1096 }
1097
1098 static int __init hibernate_setup(char *str)
1099 {
1100         if (!strncmp(str, "noresume", 8))
1101                 noresume = 1;
1102         else if (!strncmp(str, "nocompress", 10))
1103                 nocompress = 1;
1104         return 1;
1105 }
1106
1107 static int __init noresume_setup(char *str)
1108 {
1109         noresume = 1;
1110         return 1;
1111 }
1112
1113 static int __init resumewait_setup(char *str)
1114 {
1115         resume_wait = 1;
1116         return 1;
1117 }
1118
1119 static int __init resumedelay_setup(char *str)
1120 {
1121         int rc = kstrtouint(str, 0, &resume_delay);
1122
1123         if (rc)
1124                 return rc;
1125         return 1;
1126 }
1127
1128 __setup("noresume", noresume_setup);
1129 __setup("resume_offset=", resume_offset_setup);
1130 __setup("resume=", resume_setup);
1131 __setup("hibernate=", hibernate_setup);
1132 __setup("resumewait", resumewait_setup);
1133 __setup("resumedelay=", resumedelay_setup);