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 <linux/ktime.h>
  32 #include <trace/events/power.h>
  33 #include <soc/qcom/boot_stats.h>
  34
  35 #include "power.h"
  36
  37
  38 static int nocompress;
  39 static int noresume;
  40 static int nohibernate;
  41 static int resume_wait;
  42 static unsigned int resume_delay;
  43 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  44 dev_t swsusp_resume_device;
  45 sector_t swsusp_resume_block;
  46 __visible int in_suspend __nosavedata;
  47
  48 enum {
  49         HIBERNATION_INVALID,
  50         HIBERNATION_PLATFORM,
  51         HIBERNATION_SHUTDOWN,
  52         HIBERNATION_REBOOT,
  53 #ifdef CONFIG_SUSPEND
  54         HIBERNATION_SUSPEND,
  55 #endif
  56         /* keep last */
  57         __HIBERNATION_AFTER_LAST
  58 };
  59 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  60 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  61
  62 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  63
  64 bool freezer_test_done;
  65
  66 static const struct platform_hibernation_ops *hibernation_ops;
  67
  68 bool hibernation_available(void)
  69 {
  70         return (nohibernate == 0);
  71 }
  72
  73 /**
  74  * hibernation_set_ops - Set the global hibernate operations.
  75  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  76  */
  77 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  78 {
  79         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  80             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  81             && ops->restore_cleanup && ops->leave)) {
  82                 WARN_ON(1);
  83                 return;
  84         }
  85         lock_system_sleep();
  86         hibernation_ops = ops;
  87         if (ops)
  88                 hibernation_mode = HIBERNATION_PLATFORM;
  89         else if (hibernation_mode == HIBERNATION_PLATFORM)
  90                 hibernation_mode = HIBERNATION_SHUTDOWN;
  91
  92         unlock_system_sleep();
  93 }
  94 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  95
  96 static bool entering_platform_hibernation;
  97
  98 bool system_entering_hibernation(void)
  99 {
 100         return entering_platform_hibernation;
 101 }
 102 EXPORT_SYMBOL(system_entering_hibernation);
 103
 104 #ifdef CONFIG_PM_DEBUG
 105 static void hibernation_debug_sleep(void)
 106 {
 107         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 108         mdelay(5000);
 109 }
 110
 111 static int hibernation_test(int level)
 112 {
 113         if (pm_test_level == level) {
 114                 hibernation_debug_sleep();
 115                 return 1;
 116         }
 117         return 0;
 118 }
 119 #else /* !CONFIG_PM_DEBUG */
 120 static int hibernation_test(int level) { return 0; }
 121 #endif /* !CONFIG_PM_DEBUG */
 122
 123 /**
 124  * platform_begin - Call platform to start hibernation.
 125  * @platform_mode: Whether or not to use the platform driver.
 126  */
 127 static int platform_begin(int platform_mode)
 128 {
 129         return (platform_mode && hibernation_ops) ?
 130                 hibernation_ops->begin() : 0;
 131 }
 132
 133 /**
 134  * platform_end - Call platform to finish transition to the working state.
 135  * @platform_mode: Whether or not to use the platform driver.
 136  */
 137 static void platform_end(int platform_mode)
 138 {
 139         if (platform_mode && hibernation_ops)
 140                 hibernation_ops->end();
 141 }
 142
 143 /**
 144  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 145  * @platform_mode: Whether or not to use the platform driver.
 146  *
 147  * Use the platform driver to prepare the system for creating a hibernate image,
 148  * if so configured, and return an error code if that fails.
 149  */
 150
 151 static int platform_pre_snapshot(int platform_mode)
 152 {
 153         return (platform_mode && hibernation_ops) ?
 154                 hibernation_ops->pre_snapshot() : 0;
 155 }
 156
 157 /**
 158  * platform_leave - Call platform to prepare a transition to the working state.
 159  * @platform_mode: Whether or not to use the platform driver.
 160  *
 161  * Use the platform driver prepare to prepare the machine for switching to the
 162  * normal mode of operation.
 163  *
 164  * This routine is called on one CPU with interrupts disabled.
 165  */
 166 static void platform_leave(int platform_mode)
 167 {
 168         if (platform_mode && hibernation_ops)
 169                 hibernation_ops->leave();
 170 }
 171
 172 /**
 173  * platform_finish - Call platform to switch the system to the working state.
 174  * @platform_mode: Whether or not to use the platform driver.
 175  *
 176  * Use the platform driver to switch the machine to the normal mode of
 177  * operation.
 178  *
 179  * This routine must be called after platform_prepare().
 180  */
 181 static void platform_finish(int platform_mode)
 182 {
 183         if (platform_mode && hibernation_ops)
 184                 hibernation_ops->finish();
 185 }
 186
 187 /**
 188  * platform_pre_restore - Prepare for hibernate image restoration.
 189  * @platform_mode: Whether or not to use the platform driver.
 190  *
 191  * Use the platform driver to prepare the system for resume from a hibernation
 192  * image.
 193  *
 194  * If the restore fails after this function has been called,
 195  * platform_restore_cleanup() must be called.
 196  */
 197 static int platform_pre_restore(int platform_mode)
 198 {
 199         return (platform_mode && hibernation_ops) ?
 200                 hibernation_ops->pre_restore() : 0;
 201 }
 202
 203 /**
 204  * platform_restore_cleanup - Switch to the working state after failing restore.
 205  * @platform_mode: Whether or not to use the platform driver.
 206  *
 207  * Use the platform driver to switch the system to the normal mode of operation
 208  * after a failing restore.
 209  *
 210  * If platform_pre_restore() has been called before the failing restore, this
 211  * function must be called too, regardless of the result of
 212  * platform_pre_restore().
 213  */
 214 static void platform_restore_cleanup(int platform_mode)
 215 {
 216         if (platform_mode && hibernation_ops)
 217                 hibernation_ops->restore_cleanup();
 218 }
 219
 220 /**
 221  * platform_recover - Recover from a failure to suspend devices.
 222  * @platform_mode: Whether or not to use the platform driver.
 223  */
 224 static void platform_recover(int platform_mode)
 225 {
 226         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 227                 hibernation_ops->recover();
 228 }
 229
 230 /**
 231  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 232  * @start: Starting event.
 233  * @stop: Final event.
 234  * @nr_pages: Number of memory pages processed between @start and @stop.
 235  * @msg: Additional diagnostic message to print.
 236  */
 237 void swsusp_show_speed(ktime_t start, ktime_t stop,
 238                       unsigned nr_pages, char *msg)
 239 {
 240         ktime_t diff;
 241         u64 elapsed_centisecs64;
 242         unsigned int centisecs;
 243         unsigned int k;
 244         unsigned int kps;
 245
 246         diff = ktime_sub(stop, start);
 247         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 248         centisecs = elapsed_centisecs64;
 249         if (centisecs == 0)
 250                 centisecs = 1;  /* avoid div-by-zero */
 251         k = nr_pages * (PAGE_SIZE / 1024);
 252         kps = (k * 100) / centisecs;
 253         printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 254                         msg, k,
 255                         centisecs / 100, centisecs % 100,
 256                         kps / 1000, (kps % 1000) / 10);
 257 }
 258
 259 /**
 260  * create_image - Create a hibernation image.
 261  * @platform_mode: Whether or not to use the platform driver.
 262  *
 263  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 264  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 265  *
 266  * Control reappears in this routine after the subsequent restore.
 267  */
 268 static int create_image(int platform_mode)
 269 {
 270         int error;
 271
 272         error = dpm_suspend_end(PMSG_FREEZE);
 273         if (error) {
 274                 printk(KERN_ERR "PM: Some devices failed to power down, "
 275                         "aborting hibernation\n");
 276                 return error;
 277         }
 278
 279         error = platform_pre_snapshot(platform_mode);
 280         if (error || hibernation_test(TEST_PLATFORM))
 281                 goto Platform_finish;
 282
 283         error = disable_nonboot_cpus();
 284         if (error || hibernation_test(TEST_CPUS))
 285                 goto Enable_cpus;
 286
 287         local_irq_disable();
 288
 289         error = syscore_suspend();
 290         if (error) {
 291                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 292                         "aborting hibernation\n");
 293                 goto Enable_irqs;
 294         }
 295
 296         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 297                 goto Power_up;
 298
 299         in_suspend = 1;
 300         save_processor_state();
 301         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 302         error = swsusp_arch_suspend();
 303         /* Restore control flow magically appears here */
 304         restore_processor_state();
 305         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 306         if (error)
 307                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 308                         error);
 309         if (!in_suspend)
 310                 events_check_enabled = false;
 311
 312         platform_leave(platform_mode);
 313
 314  Power_up:
 315         syscore_resume();
 316
 317  Enable_irqs:
 318         local_irq_enable();
 319
 320  Enable_cpus:
 321         enable_nonboot_cpus();
 322
 323  Platform_finish:
 324         platform_finish(platform_mode);
 325
 326         dpm_resume_start(in_suspend ?
 327                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 328
 329         return error;
 330 }
 331
 332 /**
 333  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 334  * @platform_mode: If set, use platform driver to prepare for the transition.
 335  *
 336  * This routine must be called with pm_mutex held.
 337  */
 338 int hibernation_snapshot(int platform_mode)
 339 {
 340         pm_message_t msg;
 341         int error;
 342
 343         pm_suspend_clear_flags();
 344         error = platform_begin(platform_mode);
 345         if (error)
 346                 goto Close;
 347
 348         /* Preallocate image memory before shutting down devices. */
 349         error = hibernate_preallocate_memory();
 350         if (error)
 351                 goto Close;
 352
 353         error = freeze_kernel_threads();
 354         if (error)
 355                 goto Cleanup;
 356
 357         if (hibernation_test(TEST_FREEZER)) {
 358
 359                 /*
 360                  * Indicate to the caller that we are returning due to a
 361                  * successful freezer test.
 362                  */
 363                 freezer_test_done = true;
 364                 goto Thaw;
 365         }
 366
 367         error = dpm_prepare(PMSG_FREEZE);
 368         if (error) {
 369                 dpm_complete(PMSG_RECOVER);
 370                 goto Thaw;
 371         }
 372
 373         suspend_console();
 374         pm_restrict_gfp_mask();
 375
 376         error = dpm_suspend(PMSG_FREEZE);
 377
 378         if (error || hibernation_test(TEST_DEVICES))
 379                 platform_recover(platform_mode);
 380         else
 381                 error = create_image(platform_mode);
 382
 383         /*
 384          * In the case that we call create_image() above, the control
 385          * returns here (1) after the image has been created or the
 386          * image creation has failed and (2) after a successful restore.
 387          */
 388
 389         /* We may need to release the preallocated image pages here. */
 390         if (error || !in_suspend)
 391                 swsusp_free();
 392
 393         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 394         dpm_resume(msg);
 395
 396         if (error || !in_suspend)
 397                 pm_restore_gfp_mask();
 398
 399         resume_console();
 400         dpm_complete(msg);
 401
 402  Close:
 403         platform_end(platform_mode);
 404         return error;
 405
 406  Thaw:
 407         thaw_kernel_threads();
 408  Cleanup:
 409         swsusp_free();
 410         goto Close;
 411 }
 412
 413 /**
 414  * resume_target_kernel - Restore system state from a hibernation image.
 415  * @platform_mode: Whether or not to use the platform driver.
 416  *
 417  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 418  * contents of highmem that have not been restored yet from the image and run
 419  * the low-level code that will restore the remaining contents of memory and
 420  * switch to the just restored target kernel.
 421  */
 422 static int resume_target_kernel(bool platform_mode)
 423 {
 424         int error;
 425
 426         error = dpm_suspend_end(PMSG_QUIESCE);
 427         if (error) {
 428                 printk(KERN_ERR "PM: Some devices failed to power down, "
 429                         "aborting resume\n");
 430                 return error;
 431         }
 432
 433         error = platform_pre_restore(platform_mode);
 434         if (error)
 435                 goto Cleanup;
 436
 437         error = disable_nonboot_cpus();
 438         if (error)
 439                 goto Enable_cpus;
 440
 441         local_irq_disable();
 442
 443         error = syscore_suspend();
 444         if (error)
 445                 goto Enable_irqs;
 446
 447         save_processor_state();
 448         error = restore_highmem();
 449         if (!error) {
 450                 error = swsusp_arch_resume();
 451                 /*
 452                  * The code below is only ever reached in case of a failure.
 453                  * Otherwise, execution continues at the place where
 454                  * swsusp_arch_suspend() was called.
 455                  */
 456                 BUG_ON(!error);
 457                 /*
 458                  * This call to restore_highmem() reverts the changes made by
 459                  * the previous one.
 460                  */
 461                 restore_highmem();
 462         }
 463         /*
 464          * The only reason why swsusp_arch_resume() can fail is memory being
 465          * very tight, so we have to free it as soon as we can to avoid
 466          * subsequent failures.
 467          */
 468         swsusp_free();
 469         restore_processor_state();
 470         touch_softlockup_watchdog();
 471
 472         syscore_resume();
 473         place_marker("PM: Image Restoration failed!");
 474
 475  Enable_irqs:
 476         local_irq_enable();
 477
 478  Enable_cpus:
 479         enable_nonboot_cpus();
 480
 481  Cleanup:
 482         platform_restore_cleanup(platform_mode);
 483
 484         dpm_resume_start(PMSG_RECOVER);
 485
 486         return error;
 487 }
 488
 489 /**
 490  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 491  * @platform_mode: If set, use platform driver to prepare for the transition.
 492  *
 493  * This routine must be called with pm_mutex held.  If it is successful, control
 494  * reappears in the restored target kernel in hibernation_snapshot().
 495  */
 496 int hibernation_restore(int platform_mode)
 497 {
 498         int error;
 499
 500         pm_prepare_console();
 501         suspend_console();
 502         pm_restrict_gfp_mask();
 503         error = dpm_suspend_start(PMSG_QUIESCE);
 504         if (!error) {
 505                 error = resume_target_kernel(platform_mode);
 506                 /*
 507                  * The above should either succeed and jump to the new kernel,
 508                  * or return with an error. Otherwise things are just
 509                  * undefined, so let's be paranoid.
 510                  */
 511                 BUG_ON(!error);
 512         }
 513         dpm_resume_end(PMSG_RECOVER);
 514         pm_restore_gfp_mask();
 515         resume_console();
 516         pm_restore_console();
 517         return error;
 518 }
 519
 520 /**
 521  * hibernation_platform_enter - Power off the system using the platform driver.
 522  */
 523 int hibernation_platform_enter(void)
 524 {
 525         int error;
 526
 527         if (!hibernation_ops)
 528                 return -ENOSYS;
 529
 530         /*
 531          * We have cancelled the power transition by running
 532          * hibernation_ops->finish() before saving the image, so we should let
 533          * the firmware know that we're going to enter the sleep state after all
 534          */
 535         error = hibernation_ops->begin();
 536         if (error)
 537                 goto Close;
 538
 539         entering_platform_hibernation = true;
 540         suspend_console();
 541         error = dpm_suspend_start(PMSG_HIBERNATE);
 542         if (error) {
 543                 if (hibernation_ops->recover)
 544                         hibernation_ops->recover();
 545                 goto Resume_devices;
 546         }
 547
 548         error = dpm_suspend_end(PMSG_HIBERNATE);
 549         if (error)
 550                 goto Resume_devices;
 551
 552         error = hibernation_ops->prepare();
 553         if (error)
 554                 goto Platform_finish;
 555
 556         error = disable_nonboot_cpus();
 557         if (error)
 558                 goto Enable_cpus;
 559
 560         local_irq_disable();
 561         syscore_suspend();
 562         if (pm_wakeup_pending()) {
 563                 error = -EAGAIN;
 564                 goto Power_up;
 565         }
 566
 567         hibernation_ops->enter();
 568         /* We should never get here */
 569         while (1);
 570
 571  Power_up:
 572         syscore_resume();
 573         local_irq_enable();
 574
 575  Enable_cpus:
 576         enable_nonboot_cpus();
 577
 578  Platform_finish:
 579         hibernation_ops->finish();
 580
 581         dpm_resume_start(PMSG_RESTORE);
 582
 583  Resume_devices:
 584         entering_platform_hibernation = false;
 585         dpm_resume_end(PMSG_RESTORE);
 586         resume_console();
 587
 588  Close:
 589         hibernation_ops->end();
 590
 591         return error;
 592 }
 593
 594 /**
 595  * power_down - Shut the machine down for hibernation.
 596  *
 597  * Use the platform driver, if configured, to put the system into the sleep
 598  * state corresponding to hibernation, or try to power it off or reboot,
 599  * depending on the value of hibernation_mode.
 600  */
 601 static void power_down(void)
 602 {
 603 #ifdef CONFIG_SUSPEND
 604         int error;
 605 #endif
 606
 607         switch (hibernation_mode) {
 608         case HIBERNATION_REBOOT:
 609                 kernel_restart(NULL);
 610                 break;
 611         case HIBERNATION_PLATFORM:
 612                 hibernation_platform_enter();
 613         case HIBERNATION_SHUTDOWN:
 614                 if (pm_power_off)
 615                         kernel_power_off();
 616                 break;
 617 #ifdef CONFIG_SUSPEND
 618         case HIBERNATION_SUSPEND:
 619                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 620                 if (error) {
 621                         if (hibernation_ops)
 622                                 hibernation_mode = HIBERNATION_PLATFORM;
 623                         else
 624                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 625                         power_down();
 626                 }
 627                 /*
 628                  * Restore swap signature.
 629                  */
 630                 error = swsusp_unmark();
 631                 if (error)
 632                         printk(KERN_ERR "PM: Swap will be unusable! "
 633                                         "Try swapon -a.\n");
 634                 return;
 635 #endif
 636         }
 637         kernel_halt();
 638         /*
 639          * Valid image is on the disk, if we continue we risk serious data
 640          * corruption after resume.
 641          */
 642         printk(KERN_CRIT "PM: Please power down manually\n");
 643         while (1)
 644                 cpu_relax();
 645 }
 646
 647 /**
 648  * hibernate - Carry out system hibernation, including saving the image.
 649  */
 650 int hibernate(void)
 651 {
 652         int error, nr_calls = 0;
 653
 654         if (!hibernation_available()) {
 655                 pr_debug("PM: Hibernation not available.\n");
 656                 return -EPERM;
 657         }
 658
 659         lock_system_sleep();
 660         /* The snapshot device should not be opened while we're running */
 661         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 662                 error = -EBUSY;
 663                 goto Unlock;
 664         }
 665
 666         pm_prepare_console();
 667         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 668         if (error) {
 669                 nr_calls--;
 670                 goto Exit;
 671         }
 672
 673         printk(KERN_INFO "PM: Syncing filesystems ... ");
 674         sys_sync();
 675         printk("done.\n");
 676
 677         error = freeze_processes();
 678         if (error)
 679                 goto Exit;
 680
 681         lock_device_hotplug();
 682         /* Allocate memory management structures */
 683         error = create_basic_memory_bitmaps();
 684         if (error)
 685                 goto Thaw;
 686
 687         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 688         if (error || freezer_test_done)
 689                 goto Free_bitmaps;
 690
 691         if (in_suspend) {
 692                 unsigned int flags = 0;
 693
 694                 if (hibernation_mode == HIBERNATION_PLATFORM)
 695                         flags |= SF_PLATFORM_MODE;
 696                 if (nocompress)
 697                         flags |= SF_NOCOMPRESS_MODE;
 698                 else
 699                         flags |= SF_CRC32_MODE;
 700
 701                 pr_debug("PM: writing image.\n");
 702                 error = swsusp_write(flags);
 703                 swsusp_free();
 704                 if (!error)
 705                         power_down();
 706                 in_suspend = 0;
 707                 pm_restore_gfp_mask();
 708         } else {
 709                 pr_debug("PM: Image restored successfully.\n");
 710                 place_marker("PM: Image restored!");
 711         }
 712
 713  Free_bitmaps:
 714         free_basic_memory_bitmaps();
 715  Thaw:
 716         unlock_device_hotplug();
 717         thaw_processes();
 718
 719         /* Don't bother checking whether freezer_test_done is true */
 720         freezer_test_done = false;
 721  Exit:
 722         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 723         pm_restore_console();
 724         atomic_inc(&snapshot_device_available);
 725  Unlock:
 726         unlock_system_sleep();
 727         return error;
 728 }
 729
 730
 731 /**
 732  * software_resume - Resume from a saved hibernation image.
 733  *
 734  * This routine is called as a late initcall, when all devices have been
 735  * discovered and initialized already.
 736  *
 737  * The image reading code is called to see if there is a hibernation image
 738  * available for reading.  If that is the case, devices are quiesced and the
 739  * contents of memory is restored from the saved image.
 740  *
 741  * If this is successful, control reappears in the restored target kernel in
 742  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 743  * attempts to recover gracefully and make the kernel return to the normal mode
 744  * of operation.
 745  */
 746 static int software_resume(void)
 747 {
 748         int error, nr_calls = 0;
 749         unsigned int flags;
 750
 751         /*
 752          * If the user said "noresume".. bail out early.
 753          */
 754         if (noresume || !hibernation_available())
 755                 return 0;
 756
 757         /*
 758          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 759          * is configured into the kernel. Since the regular hibernate
 760          * trigger path is via sysfs which takes a buffer mutex before
 761          * calling hibernate functions (which take pm_mutex) this can
 762          * cause lockdep to complain about a possible ABBA deadlock
 763          * which cannot happen since we're in the boot code here and
 764          * sysfs can't be invoked yet. Therefore, we use a subclass
 765          * here to avoid lockdep complaining.
 766          */
 767         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 768
 769         if (swsusp_resume_device)
 770                 goto Check_image;
 771
 772         if (!strlen(resume_file)) {
 773                 error = -ENOENT;
 774                 goto Unlock;
 775         }
 776
 777         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 778
 779         if (resume_delay) {
 780                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 781                         resume_delay);
 782                 ssleep(resume_delay);
 783         }
 784
 785         /* Check if the device is there */
 786         swsusp_resume_device = name_to_dev_t(resume_file);
 787
 788         /*
 789          * name_to_dev_t is ineffective to verify parition if resume_file is in
 790          * integer format. (e.g. major:minor)
 791          */
 792         if (isdigit(resume_file[0]) && resume_wait) {
 793                 int partno;
 794                 while (!get_gendisk(swsusp_resume_device, &partno))
 795                         msleep(10);
 796         }
 797
 798         if (!swsusp_resume_device) {
 799                 /*
 800                  * Some device discovery might still be in progress; we need
 801                  * to wait for this to finish.
 802                  */
 803                 wait_for_device_probe();
 804
 805                 if (resume_wait) {
 806                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 807                                 msleep(10);
 808                         async_synchronize_full();
 809                 }
 810
 811                 swsusp_resume_device = name_to_dev_t(resume_file);
 812                 if (!swsusp_resume_device) {
 813                         error = -ENODEV;
 814                         goto Unlock;
 815                 }
 816         }
 817
 818  Check_image:
 819         pr_debug("PM: Hibernation image partition %d:%d present\n",
 820                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 821
 822         pr_debug("PM: Looking for hibernation image.\n");
 823         error = swsusp_check();
 824         if (error)
 825                 goto Unlock;
 826
 827         /* The snapshot device should not be opened while we're running */
 828         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 829                 error = -EBUSY;
 830                 swsusp_close(FMODE_READ);
 831                 goto Unlock;
 832         }
 833
 834         pm_prepare_console();
 835         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 836         if (error) {
 837                 nr_calls--;
 838                 goto Close_Finish;
 839         }
 840
 841         pr_debug("PM: Preparing processes for restore.\n");
 842         error = freeze_processes();
 843         if (error)
 844                 goto Close_Finish;
 845
 846         pr_debug("PM: Loading hibernation image.\n");
 847
 848         lock_device_hotplug();
 849         error = create_basic_memory_bitmaps();
 850         if (error)
 851                 goto Thaw;
 852
 853         error = swsusp_read(&flags);
 854         swsusp_close(FMODE_READ);
 855         if (!error)
 856                 hibernation_restore(flags & SF_PLATFORM_MODE);
 857
 858         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 859         swsusp_free();
 860         free_basic_memory_bitmaps();
 861  Thaw:
 862         unlock_device_hotplug();
 863         thaw_processes();
 864  Finish:
 865         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 866         pm_restore_console();
 867         atomic_inc(&snapshot_device_available);
 868         /* For success case, the suspend path will release the lock */
 869  Unlock:
 870         mutex_unlock(&pm_mutex);
 871         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 872         return error;
 873  Close_Finish:
 874         swsusp_close(FMODE_READ);
 875         goto Finish;
 876 }
 877
 878 late_initcall_sync(software_resume);
 879
 880
 881 static const char * const hibernation_modes[] = {
 882         [HIBERNATION_PLATFORM]  = "platform",
 883         [HIBERNATION_SHUTDOWN]  = "shutdown",
 884         [HIBERNATION_REBOOT]    = "reboot",
 885 #ifdef CONFIG_SUSPEND
 886         [HIBERNATION_SUSPEND]   = "suspend",
 887 #endif
 888 };
 889
 890 /*
 891  * /sys/power/disk - Control hibernation mode.
 892  *
 893  * Hibernation can be handled in several ways.  There are a few different ways
 894  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 895  * or other hibernation_ops), powering it off or rebooting it (for testing
 896  * mostly).
 897  *
 898  * The sysfs file /sys/power/disk provides an interface for selecting the
 899  * hibernation mode to use.  Reading from this file causes the available modes
 900  * to be printed.  There are 3 modes that can be supported:
 901  *
 902  *      'platform'
 903  *      'shutdown'
 904  *      'reboot'
 905  *
 906  * If a platform hibernation driver is in use, 'platform' will be supported
 907  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 908  * The selected option (i.e. the one corresponding to the current value of
 909  * hibernation_mode) is enclosed by a square bracket.
 910  *
 911  * To select a given hibernation mode it is necessary to write the mode's
 912  * string representation (as returned by reading from /sys/power/disk) back
 913  * into /sys/power/disk.
 914  */
 915
 916 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 917                          char *buf)
 918 {
 919         int i;
 920         char *start = buf;
 921
 922         if (!hibernation_available())
 923                 return sprintf(buf, "[disabled]\n");
 924
 925         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 926                 if (!hibernation_modes[i])
 927                         continue;
 928                 switch (i) {
 929                 case HIBERNATION_SHUTDOWN:
 930                 case HIBERNATION_REBOOT:
 931 #ifdef CONFIG_SUSPEND
 932                 case HIBERNATION_SUSPEND:
 933 #endif
 934                         break;
 935                 case HIBERNATION_PLATFORM:
 936                         if (hibernation_ops)
 937                                 break;
 938                         /* not a valid mode, continue with loop */
 939                         continue;
 940                 }
 941                 if (i == hibernation_mode)
 942                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 943                 else
 944                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 945         }
 946         buf += sprintf(buf, "\n");
 947         return buf-start;
 948 }
 949
 950 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 951                           const char *buf, size_t n)
 952 {
 953         int error = 0;
 954         int i;
 955         int len;
 956         char *p;
 957         int mode = HIBERNATION_INVALID;
 958
 959         if (!hibernation_available())
 960                 return -EPERM;
 961
 962         p = memchr(buf, '\n', n);
 963         len = p ? p - buf : n;
 964
 965         lock_system_sleep();
 966         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 967                 if (len == strlen(hibernation_modes[i])
 968                     && !strncmp(buf, hibernation_modes[i], len)) {
 969                         mode = i;
 970                         break;
 971                 }
 972         }
 973         if (mode != HIBERNATION_INVALID) {
 974                 switch (mode) {
 975                 case HIBERNATION_SHUTDOWN:
 976                 case HIBERNATION_REBOOT:
 977 #ifdef CONFIG_SUSPEND
 978                 case HIBERNATION_SUSPEND:
 979 #endif
 980                         hibernation_mode = mode;
 981                         break;
 982                 case HIBERNATION_PLATFORM:
 983                         if (hibernation_ops)
 984                                 hibernation_mode = mode;
 985                         else
 986                                 error = -EINVAL;
 987                 }
 988         } else
 989                 error = -EINVAL;
 990
 991         if (!error)
 992                 pr_debug("PM: Hibernation mode set to '%s'\n",
 993                          hibernation_modes[mode]);
 994         unlock_system_sleep();
 995         return error ? error : n;
 996 }
 997
 998 power_attr(disk);
 999
1000 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1001                            char *buf)
1002 {
1003         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1004                        MINOR(swsusp_resume_device));
1005 }
1006
1007 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1008                             const char *buf, size_t n)
1009 {
1010         dev_t res;
1011         int len = n;
1012         char *name;
1013
1014         if (len && buf[len-1] == '\n')
1015                 len--;
1016         name = kstrndup(buf, len, GFP_KERNEL);
1017         if (!name)
1018                 return -ENOMEM;
1019
1020         res = name_to_dev_t(name);
1021         kfree(name);
1022         if (!res)
1023                 return -EINVAL;
1024
1025         lock_system_sleep();
1026         swsusp_resume_device = res;
1027         unlock_system_sleep();
1028         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1029         noresume = 0;
1030         software_resume();
1031         return n;
1032 }
1033
1034 power_attr(resume);
1035
1036 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1037                                char *buf)
1038 {
1039         return sprintf(buf, "%lu\n", image_size);
1040 }
1041
1042 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1043                                 const char *buf, size_t n)
1044 {
1045         unsigned long size;
1046
1047         if (sscanf(buf, "%lu", &size) == 1) {
1048                 image_size = size;
1049                 return n;
1050         }
1051
1052         return -EINVAL;
1053 }
1054
1055 power_attr(image_size);
1056
1057 static ssize_t reserved_size_show(struct kobject *kobj,
1058                                   struct kobj_attribute *attr, char *buf)
1059 {
1060         return sprintf(buf, "%lu\n", reserved_size);
1061 }
1062
1063 static ssize_t reserved_size_store(struct kobject *kobj,
1064                                    struct kobj_attribute *attr,
1065                                    const char *buf, size_t n)
1066 {
1067         unsigned long size;
1068
1069         if (sscanf(buf, "%lu", &size) == 1) {
1070                 reserved_size = size;
1071                 return n;
1072         }
1073
1074         return -EINVAL;
1075 }
1076
1077 power_attr(reserved_size);
1078
1079 static struct attribute * g[] = {
1080         &disk_attr.attr,
1081         &resume_attr.attr,
1082         &image_size_attr.attr,
1083         &reserved_size_attr.attr,
1084         NULL,
1085 };
1086
1087
1088 static struct attribute_group attr_group = {
1089         .attrs = g,
1090 };
1091
1092
1093 static int __init pm_disk_init(void)
1094 {
1095         return sysfs_create_group(power_kobj, &attr_group);
1096 }
1097
1098 core_initcall(pm_disk_init);
1099
1100
1101 static int __init resume_setup(char *str)
1102 {
1103         if (noresume)
1104                 return 1;
1105
1106         strncpy( resume_file, str, 255 );
1107         return 1;
1108 }
1109
1110 static int __init resume_offset_setup(char *str)
1111 {
1112         unsigned long long offset;
1113
1114         if (noresume)
1115                 return 1;
1116
1117         if (sscanf(str, "%llu", &offset) == 1)
1118                 swsusp_resume_block = offset;
1119
1120         return 1;
1121 }
1122
1123 static int __init hibernate_setup(char *str)
1124 {
1125         if (!strncmp(str, "noresume", 8))
1126                 noresume = 1;
1127         else if (!strncmp(str, "nocompress", 10))
1128                 nocompress = 1;
1129         else if (!strncmp(str, "no", 2)) {
1130                 noresume = 1;
1131                 nohibernate = 1;
1132         }
1133         return 1;
1134 }
1135
1136 static int __init noresume_setup(char *str)
1137 {
1138         noresume = 1;
1139         return 1;
1140 }
1141
1142 static int __init resumewait_setup(char *str)
1143 {
1144         resume_wait = 1;
1145         return 1;
1146 }
1147
1148 static int __init resumedelay_setup(char *str)
1149 {
1150         int rc = kstrtouint(str, 0, &resume_delay);
1151
1152         if (rc)
1153                 return rc;
1154         return 1;
1155 }
1156
1157 static int __init nohibernate_setup(char *str)
1158 {
1159         noresume = 1;
1160         nohibernate = 1;
1161         return 1;
1162 }
1163
1164 static int __init kaslr_nohibernate_setup(char *str)
1165 {
1166         return nohibernate_setup(str);
1167 }
1168
1169 static int __init page_poison_nohibernate_setup(char *str)
1170 {
1171 #ifdef CONFIG_PAGE_POISONING_ZERO
1172         /*
1173          * The zeroing option for page poison skips the checks on alloc.
1174          * since hibernation doesn't save free pages there's no way to
1175          * guarantee the pages will still be zeroed.
1176          */
1177         if (!strcmp(str, "on")) {
1178                 pr_info("Disabling hibernation due to page poisoning\n");
1179                 return nohibernate_setup(str);
1180         }
1181 #endif
1182         return 1;
1183 }
1184
1185 __setup("noresume", noresume_setup);
1186 __setup("resume_offset=", resume_offset_setup);
1187 __setup("resume=", resume_setup);
1188 __setup("hibernate=", hibernate_setup);
1189 __setup("resumewait", resumewait_setup);
1190 __setup("resumedelay=", resumedelay_setup);
1191 __setup("nohibernate", nohibernate_setup);
1192 __setup("kaslr", kaslr_nohibernate_setup);
1193 __setup("page_poison=", page_poison_nohibernate_setup);