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
  34 #include "power.h"
  35
  36
  37 static int nocompress;
  38 static int noresume;
  39 static int nohibernate;
  40 static int resume_wait;
  41 static unsigned int resume_delay;
  42 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  43 dev_t swsusp_resume_device;
  44 sector_t swsusp_resume_block;
  45 __visible int in_suspend __nosavedata;
  46
  47 enum {
  48         HIBERNATION_INVALID,
  49         HIBERNATION_PLATFORM,
  50         HIBERNATION_SHUTDOWN,
  51         HIBERNATION_REBOOT,
  52 #ifdef CONFIG_SUSPEND
  53         HIBERNATION_SUSPEND,
  54 #endif
  55         /* keep last */
  56         __HIBERNATION_AFTER_LAST
  57 };
  58 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  59 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  60
  61 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  62
  63 bool freezer_test_done;
  64
  65 static const struct platform_hibernation_ops *hibernation_ops;
  66
  67 bool hibernation_available(void)
  68 {
  69         return (nohibernate == 0);
  70 }
  71
  72 /**
  73  * hibernation_set_ops - Set the global hibernate operations.
  74  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  75  */
  76 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  77 {
  78         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  79             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  80             && ops->restore_cleanup && ops->leave)) {
  81                 WARN_ON(1);
  82                 return;
  83         }
  84         lock_system_sleep();
  85         hibernation_ops = ops;
  86         if (ops)
  87                 hibernation_mode = HIBERNATION_PLATFORM;
  88         else if (hibernation_mode == HIBERNATION_PLATFORM)
  89                 hibernation_mode = HIBERNATION_SHUTDOWN;
  90
  91         unlock_system_sleep();
  92 }
  93 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  94
  95 static bool entering_platform_hibernation;
  96
  97 bool system_entering_hibernation(void)
  98 {
  99         return entering_platform_hibernation;
 100 }
 101 EXPORT_SYMBOL(system_entering_hibernation);
 102
 103 #ifdef CONFIG_PM_DEBUG
 104 static void hibernation_debug_sleep(void)
 105 {
 106         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 107         mdelay(5000);
 108 }
 109
 110 static int hibernation_test(int level)
 111 {
 112         if (pm_test_level == level) {
 113                 hibernation_debug_sleep();
 114                 return 1;
 115         }
 116         return 0;
 117 }
 118 #else /* !CONFIG_PM_DEBUG */
 119 static int hibernation_test(int level) { return 0; }
 120 #endif /* !CONFIG_PM_DEBUG */
 121
 122 /**
 123  * platform_begin - Call platform to start hibernation.
 124  * @platform_mode: Whether or not to use the platform driver.
 125  */
 126 static int platform_begin(int platform_mode)
 127 {
 128         return (platform_mode && hibernation_ops) ?
 129                 hibernation_ops->begin() : 0;
 130 }
 131
 132 /**
 133  * platform_end - Call platform to finish transition to the working state.
 134  * @platform_mode: Whether or not to use the platform driver.
 135  */
 136 static void platform_end(int platform_mode)
 137 {
 138         if (platform_mode && hibernation_ops)
 139                 hibernation_ops->end();
 140 }
 141
 142 /**
 143  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 144  * @platform_mode: Whether or not to use the platform driver.
 145  *
 146  * Use the platform driver to prepare the system for creating a hibernate image,
 147  * if so configured, and return an error code if that fails.
 148  */
 149
 150 static int platform_pre_snapshot(int platform_mode)
 151 {
 152         return (platform_mode && hibernation_ops) ?
 153                 hibernation_ops->pre_snapshot() : 0;
 154 }
 155
 156 /**
 157  * platform_leave - Call platform to prepare a transition to the working state.
 158  * @platform_mode: Whether or not to use the platform driver.
 159  *
 160  * Use the platform driver prepare to prepare the machine for switching to the
 161  * normal mode of operation.
 162  *
 163  * This routine is called on one CPU with interrupts disabled.
 164  */
 165 static void platform_leave(int platform_mode)
 166 {
 167         if (platform_mode && hibernation_ops)
 168                 hibernation_ops->leave();
 169 }
 170
 171 /**
 172  * platform_finish - Call platform to switch the system to the working state.
 173  * @platform_mode: Whether or not to use the platform driver.
 174  *
 175  * Use the platform driver to switch the machine to the normal mode of
 176  * operation.
 177  *
 178  * This routine must be called after platform_prepare().
 179  */
 180 static void platform_finish(int platform_mode)
 181 {
 182         if (platform_mode && hibernation_ops)
 183                 hibernation_ops->finish();
 184 }
 185
 186 /**
 187  * platform_pre_restore - Prepare for hibernate image restoration.
 188  * @platform_mode: Whether or not to use the platform driver.
 189  *
 190  * Use the platform driver to prepare the system for resume from a hibernation
 191  * image.
 192  *
 193  * If the restore fails after this function has been called,
 194  * platform_restore_cleanup() must be called.
 195  */
 196 static int platform_pre_restore(int platform_mode)
 197 {
 198         return (platform_mode && hibernation_ops) ?
 199                 hibernation_ops->pre_restore() : 0;
 200 }
 201
 202 /**
 203  * platform_restore_cleanup - Switch to the working state after failing restore.
 204  * @platform_mode: Whether or not to use the platform driver.
 205  *
 206  * Use the platform driver to switch the system to the normal mode of operation
 207  * after a failing restore.
 208  *
 209  * If platform_pre_restore() has been called before the failing restore, this
 210  * function must be called too, regardless of the result of
 211  * platform_pre_restore().
 212  */
 213 static void platform_restore_cleanup(int platform_mode)
 214 {
 215         if (platform_mode && hibernation_ops)
 216                 hibernation_ops->restore_cleanup();
 217 }
 218
 219 /**
 220  * platform_recover - Recover from a failure to suspend devices.
 221  * @platform_mode: Whether or not to use the platform driver.
 222  */
 223 static void platform_recover(int platform_mode)
 224 {
 225         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 226                 hibernation_ops->recover();
 227 }
 228
 229 /**
 230  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 231  * @start: Starting event.
 232  * @stop: Final event.
 233  * @nr_pages: Number of memory pages processed between @start and @stop.
 234  * @msg: Additional diagnostic message to print.
 235  */
 236 void swsusp_show_speed(ktime_t start, ktime_t stop,
 237                       unsigned nr_pages, char *msg)
 238 {
 239         ktime_t diff;
 240         u64 elapsed_centisecs64;
 241         unsigned int centisecs;
 242         unsigned int k;
 243         unsigned int kps;
 244
 245         diff = ktime_sub(stop, start);
 246         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 247         centisecs = elapsed_centisecs64;
 248         if (centisecs == 0)
 249                 centisecs = 1;  /* avoid div-by-zero */
 250         k = nr_pages * (PAGE_SIZE / 1024);
 251         kps = (k * 100) / centisecs;
 252         printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 253                         msg, k,
 254                         centisecs / 100, centisecs % 100,
 255                         kps / 1000, (kps % 1000) / 10);
 256 }
 257
 258 /**
 259  * create_image - Create a hibernation image.
 260  * @platform_mode: Whether or not to use the platform driver.
 261  *
 262  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 263  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 264  *
 265  * Control reappears in this routine after the subsequent restore.
 266  */
 267 static int create_image(int platform_mode)
 268 {
 269         int error;
 270
 271         error = dpm_suspend_end(PMSG_FREEZE);
 272         if (error) {
 273                 printk(KERN_ERR "PM: Some devices failed to power down, "
 274                         "aborting hibernation\n");
 275                 return error;
 276         }
 277
 278         error = platform_pre_snapshot(platform_mode);
 279         if (error || hibernation_test(TEST_PLATFORM))
 280                 goto Platform_finish;
 281
 282         error = disable_nonboot_cpus();
 283         if (error || hibernation_test(TEST_CPUS))
 284                 goto Enable_cpus;
 285
 286         local_irq_disable();
 287
 288         error = syscore_suspend();
 289         if (error) {
 290                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 291                         "aborting hibernation\n");
 292                 goto Enable_irqs;
 293         }
 294
 295         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 296                 goto Power_up;
 297
 298         in_suspend = 1;
 299         save_processor_state();
 300         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 301         error = swsusp_arch_suspend();
 302         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 303         if (error)
 304                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 305                         error);
 306         /* Restore control flow magically appears here */
 307         restore_processor_state();
 308         if (!in_suspend)
 309                 events_check_enabled = false;
 310
 311         platform_leave(platform_mode);
 312
 313  Power_up:
 314         syscore_resume();
 315
 316  Enable_irqs:
 317         local_irq_enable();
 318
 319  Enable_cpus:
 320         enable_nonboot_cpus();
 321
 322  Platform_finish:
 323         platform_finish(platform_mode);
 324
 325         dpm_resume_start(in_suspend ?
 326                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 327
 328         return error;
 329 }
 330
 331 /**
 332  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 333  * @platform_mode: If set, use platform driver to prepare for the transition.
 334  *
 335  * This routine must be called with pm_mutex held.
 336  */
 337 int hibernation_snapshot(int platform_mode)
 338 {
 339         pm_message_t msg;
 340         int error;
 341
 342         pm_suspend_clear_flags();
 343         error = platform_begin(platform_mode);
 344         if (error)
 345                 goto Close;
 346
 347         /* Preallocate image memory before shutting down devices. */
 348         error = hibernate_preallocate_memory();
 349         if (error)
 350                 goto Close;
 351
 352         error = freeze_kernel_threads();
 353         if (error)
 354                 goto Cleanup;
 355
 356         if (hibernation_test(TEST_FREEZER)) {
 357
 358                 /*
 359                  * Indicate to the caller that we are returning due to a
 360                  * successful freezer test.
 361                  */
 362                 freezer_test_done = true;
 363                 goto Thaw;
 364         }
 365
 366         error = dpm_prepare(PMSG_FREEZE);
 367         if (error) {
 368                 dpm_complete(PMSG_RECOVER);
 369                 goto Thaw;
 370         }
 371
 372         suspend_console();
 373         pm_restrict_gfp_mask();
 374
 375         error = dpm_suspend(PMSG_FREEZE);
 376
 377         if (error || hibernation_test(TEST_DEVICES))
 378                 platform_recover(platform_mode);
 379         else
 380                 error = create_image(platform_mode);
 381
 382         /*
 383          * In the case that we call create_image() above, the control
 384          * returns here (1) after the image has been created or the
 385          * image creation has failed and (2) after a successful restore.
 386          */
 387
 388         /* We may need to release the preallocated image pages here. */
 389         if (error || !in_suspend)
 390                 swsusp_free();
 391
 392         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 393         dpm_resume(msg);
 394
 395         if (error || !in_suspend)
 396                 pm_restore_gfp_mask();
 397
 398         resume_console();
 399         dpm_complete(msg);
 400
 401  Close:
 402         platform_end(platform_mode);
 403         return error;
 404
 405  Thaw:
 406         thaw_kernel_threads();
 407  Cleanup:
 408         swsusp_free();
 409         goto Close;
 410 }
 411
 412 int __weak hibernate_resume_nonboot_cpu_disable(void)
 413 {
 414         return disable_nonboot_cpus();
 415 }
 416
 417 /**
 418  * resume_target_kernel - Restore system state from a hibernation image.
 419  * @platform_mode: Whether or not to use the platform driver.
 420  *
 421  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 422  * contents of highmem that have not been restored yet from the image and run
 423  * the low-level code that will restore the remaining contents of memory and
 424  * switch to the just restored target kernel.
 425  */
 426 static int resume_target_kernel(bool platform_mode)
 427 {
 428         int error;
 429
 430         error = dpm_suspend_end(PMSG_QUIESCE);
 431         if (error) {
 432                 printk(KERN_ERR "PM: Some devices failed to power down, "
 433                         "aborting resume\n");
 434                 return error;
 435         }
 436
 437         error = platform_pre_restore(platform_mode);
 438         if (error)
 439                 goto Cleanup;
 440
 441         error = hibernate_resume_nonboot_cpu_disable();
 442         if (error)
 443                 goto Enable_cpus;
 444
 445         local_irq_disable();
 446
 447         error = syscore_suspend();
 448         if (error)
 449                 goto Enable_irqs;
 450
 451         save_processor_state();
 452         error = restore_highmem();
 453         if (!error) {
 454                 error = swsusp_arch_resume();
 455                 /*
 456                  * The code below is only ever reached in case of a failure.
 457                  * Otherwise, execution continues at the place where
 458                  * swsusp_arch_suspend() was called.
 459                  */
 460                 BUG_ON(!error);
 461                 /*
 462                  * This call to restore_highmem() reverts the changes made by
 463                  * the previous one.
 464                  */
 465                 restore_highmem();
 466         }
 467         /*
 468          * The only reason why swsusp_arch_resume() can fail is memory being
 469          * very tight, so we have to free it as soon as we can to avoid
 470          * subsequent failures.
 471          */
 472         swsusp_free();
 473         restore_processor_state();
 474         touch_softlockup_watchdog();
 475
 476         syscore_resume();
 477
 478  Enable_irqs:
 479         local_irq_enable();
 480
 481  Enable_cpus:
 482         enable_nonboot_cpus();
 483
 484  Cleanup:
 485         platform_restore_cleanup(platform_mode);
 486
 487         dpm_resume_start(PMSG_RECOVER);
 488
 489         return error;
 490 }
 491
 492 /**
 493  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 494  * @platform_mode: If set, use platform driver to prepare for the transition.
 495  *
 496  * This routine must be called with pm_mutex held.  If it is successful, control
 497  * reappears in the restored target kernel in hibernation_snapshot().
 498  */
 499 int hibernation_restore(int platform_mode)
 500 {
 501         int error;
 502
 503         pm_prepare_console();
 504         suspend_console();
 505         pm_restrict_gfp_mask();
 506         error = dpm_suspend_start(PMSG_QUIESCE);
 507         if (!error) {
 508                 error = resume_target_kernel(platform_mode);
 509                 /*
 510                  * The above should either succeed and jump to the new kernel,
 511                  * or return with an error. Otherwise things are just
 512                  * undefined, so let's be paranoid.
 513                  */
 514                 BUG_ON(!error);
 515         }
 516         dpm_resume_end(PMSG_RECOVER);
 517         pm_restore_gfp_mask();
 518         resume_console();
 519         pm_restore_console();
 520         return error;
 521 }
 522
 523 /**
 524  * hibernation_platform_enter - Power off the system using the platform driver.
 525  */
 526 int hibernation_platform_enter(void)
 527 {
 528         int error;
 529
 530         if (!hibernation_ops)
 531                 return -ENOSYS;
 532
 533         /*
 534          * We have cancelled the power transition by running
 535          * hibernation_ops->finish() before saving the image, so we should let
 536          * the firmware know that we're going to enter the sleep state after all
 537          */
 538         error = hibernation_ops->begin();
 539         if (error)
 540                 goto Close;
 541
 542         entering_platform_hibernation = true;
 543         suspend_console();
 544         error = dpm_suspend_start(PMSG_HIBERNATE);
 545         if (error) {
 546                 if (hibernation_ops->recover)
 547                         hibernation_ops->recover();
 548                 goto Resume_devices;
 549         }
 550
 551         error = dpm_suspend_end(PMSG_HIBERNATE);
 552         if (error)
 553                 goto Resume_devices;
 554
 555         error = hibernation_ops->prepare();
 556         if (error)
 557                 goto Platform_finish;
 558
 559         error = disable_nonboot_cpus();
 560         if (error)
 561                 goto Enable_cpus;
 562
 563         local_irq_disable();
 564         syscore_suspend();
 565         if (pm_wakeup_pending()) {
 566                 error = -EAGAIN;
 567                 goto Power_up;
 568         }
 569
 570         hibernation_ops->enter();
 571         /* We should never get here */
 572         while (1);
 573
 574  Power_up:
 575         syscore_resume();
 576         local_irq_enable();
 577
 578  Enable_cpus:
 579         enable_nonboot_cpus();
 580
 581  Platform_finish:
 582         hibernation_ops->finish();
 583
 584         dpm_resume_start(PMSG_RESTORE);
 585
 586  Resume_devices:
 587         entering_platform_hibernation = false;
 588         dpm_resume_end(PMSG_RESTORE);
 589         resume_console();
 590
 591  Close:
 592         hibernation_ops->end();
 593
 594         return error;
 595 }
 596
 597 /**
 598  * power_down - Shut the machine down for hibernation.
 599  *
 600  * Use the platform driver, if configured, to put the system into the sleep
 601  * state corresponding to hibernation, or try to power it off or reboot,
 602  * depending on the value of hibernation_mode.
 603  */
 604 static void power_down(void)
 605 {
 606 #ifdef CONFIG_SUSPEND
 607         int error;
 608 #endif
 609
 610         switch (hibernation_mode) {
 611         case HIBERNATION_REBOOT:
 612                 kernel_restart(NULL);
 613                 break;
 614         case HIBERNATION_PLATFORM:
 615                 hibernation_platform_enter();
 616         case HIBERNATION_SHUTDOWN:
 617                 if (pm_power_off)
 618                         kernel_power_off();
 619                 break;
 620 #ifdef CONFIG_SUSPEND
 621         case HIBERNATION_SUSPEND:
 622                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 623                 if (error) {
 624                         if (hibernation_ops)
 625                                 hibernation_mode = HIBERNATION_PLATFORM;
 626                         else
 627                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 628                         power_down();
 629                 }
 630                 /*
 631                  * Restore swap signature.
 632                  */
 633                 error = swsusp_unmark();
 634                 if (error)
 635                         printk(KERN_ERR "PM: Swap will be unusable! "
 636                                         "Try swapon -a.\n");
 637                 return;
 638 #endif
 639         }
 640         kernel_halt();
 641         /*
 642          * Valid image is on the disk, if we continue we risk serious data
 643          * corruption after resume.
 644          */
 645         printk(KERN_CRIT "PM: Please power down manually\n");
 646         while (1)
 647                 cpu_relax();
 648 }
 649
 650 /**
 651  * hibernate - Carry out system hibernation, including saving the image.
 652  */
 653 int hibernate(void)
 654 {
 655         int error, nr_calls = 0;
 656
 657         if (!hibernation_available()) {
 658                 pr_debug("PM: Hibernation not available.\n");
 659                 return -EPERM;
 660         }
 661
 662         lock_system_sleep();
 663         /* The snapshot device should not be opened while we're running */
 664         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 665                 error = -EBUSY;
 666                 goto Unlock;
 667         }
 668
 669         pm_prepare_console();
 670         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 671         if (error) {
 672                 nr_calls--;
 673                 goto Exit;
 674         }
 675
 676         printk(KERN_INFO "PM: Syncing filesystems ... ");
 677         sys_sync();
 678         printk("done.\n");
 679
 680         error = freeze_processes();
 681         if (error)
 682                 goto Exit;
 683
 684         lock_device_hotplug();
 685         /* Allocate memory management structures */
 686         error = create_basic_memory_bitmaps();
 687         if (error)
 688                 goto Thaw;
 689
 690         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 691         if (error || freezer_test_done)
 692                 goto Free_bitmaps;
 693
 694         if (in_suspend) {
 695                 unsigned int flags = 0;
 696
 697                 if (hibernation_mode == HIBERNATION_PLATFORM)
 698                         flags |= SF_PLATFORM_MODE;
 699                 if (nocompress)
 700                         flags |= SF_NOCOMPRESS_MODE;
 701                 else
 702                         flags |= SF_CRC32_MODE;
 703
 704                 pr_debug("PM: writing image.\n");
 705                 error = swsusp_write(flags);
 706                 swsusp_free();
 707                 if (!error)
 708                         power_down();
 709                 in_suspend = 0;
 710                 pm_restore_gfp_mask();
 711         } else {
 712                 pr_debug("PM: Image restored successfully.\n");
 713         }
 714
 715  Free_bitmaps:
 716         free_basic_memory_bitmaps();
 717  Thaw:
 718         unlock_device_hotplug();
 719         thaw_processes();
 720
 721         /* Don't bother checking whether freezer_test_done is true */
 722         freezer_test_done = false;
 723  Exit:
 724         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 725         pm_restore_console();
 726         atomic_inc(&snapshot_device_available);
 727  Unlock:
 728         unlock_system_sleep();
 729         return error;
 730 }
 731
 732
 733 /**
 734  * software_resume - Resume from a saved hibernation image.
 735  *
 736  * This routine is called as a late initcall, when all devices have been
 737  * discovered and initialized already.
 738  *
 739  * The image reading code is called to see if there is a hibernation image
 740  * available for reading.  If that is the case, devices are quiesced and the
 741  * contents of memory is restored from the saved image.
 742  *
 743  * If this is successful, control reappears in the restored target kernel in
 744  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 745  * attempts to recover gracefully and make the kernel return to the normal mode
 746  * of operation.
 747  */
 748 static int software_resume(void)
 749 {
 750         int error, nr_calls = 0;
 751         unsigned int flags;
 752
 753         /*
 754          * If the user said "noresume".. bail out early.
 755          */
 756         if (noresume || !hibernation_available())
 757                 return 0;
 758
 759         /*
 760          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 761          * is configured into the kernel. Since the regular hibernate
 762          * trigger path is via sysfs which takes a buffer mutex before
 763          * calling hibernate functions (which take pm_mutex) this can
 764          * cause lockdep to complain about a possible ABBA deadlock
 765          * which cannot happen since we're in the boot code here and
 766          * sysfs can't be invoked yet. Therefore, we use a subclass
 767          * here to avoid lockdep complaining.
 768          */
 769         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 770
 771         if (swsusp_resume_device)
 772                 goto Check_image;
 773
 774         if (!strlen(resume_file)) {
 775                 error = -ENOENT;
 776                 goto Unlock;
 777         }
 778
 779         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 780
 781         if (resume_delay) {
 782                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 783                         resume_delay);
 784                 ssleep(resume_delay);
 785         }
 786
 787         /* Check if the device is there */
 788         swsusp_resume_device = name_to_dev_t(resume_file);
 789
 790         /*
 791          * name_to_dev_t is ineffective to verify parition if resume_file is in
 792          * integer format. (e.g. major:minor)
 793          */
 794         if (isdigit(resume_file[0]) && resume_wait) {
 795                 int partno;
 796                 while (!get_gendisk(swsusp_resume_device, &partno))
 797                         msleep(10);
 798         }
 799
 800         if (!swsusp_resume_device) {
 801                 /*
 802                  * Some device discovery might still be in progress; we need
 803                  * to wait for this to finish.
 804                  */
 805                 wait_for_device_probe();
 806
 807                 if (resume_wait) {
 808                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 809                                 msleep(10);
 810                         async_synchronize_full();
 811                 }
 812
 813                 swsusp_resume_device = name_to_dev_t(resume_file);
 814                 if (!swsusp_resume_device) {
 815                         error = -ENODEV;
 816                         goto Unlock;
 817                 }
 818         }
 819
 820  Check_image:
 821         pr_debug("PM: Hibernation image partition %d:%d present\n",
 822                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 823
 824         pr_debug("PM: Looking for hibernation image.\n");
 825         error = swsusp_check();
 826         if (error)
 827                 goto Unlock;
 828
 829         /* The snapshot device should not be opened while we're running */
 830         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 831                 error = -EBUSY;
 832                 swsusp_close(FMODE_READ);
 833                 goto Unlock;
 834         }
 835
 836         pm_prepare_console();
 837         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 838         if (error) {
 839                 nr_calls--;
 840                 goto Close_Finish;
 841         }
 842
 843         pr_debug("PM: Preparing processes for restore.\n");
 844         error = freeze_processes();
 845         if (error)
 846                 goto Close_Finish;
 847
 848         pr_debug("PM: Loading hibernation image.\n");
 849
 850         lock_device_hotplug();
 851         error = create_basic_memory_bitmaps();
 852         if (error)
 853                 goto Thaw;
 854
 855         error = swsusp_read(&flags);
 856         swsusp_close(FMODE_READ);
 857         if (!error)
 858                 hibernation_restore(flags & SF_PLATFORM_MODE);
 859
 860         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 861         swsusp_free();
 862         free_basic_memory_bitmaps();
 863  Thaw:
 864         unlock_device_hotplug();
 865         thaw_processes();
 866  Finish:
 867         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 868         pm_restore_console();
 869         atomic_inc(&snapshot_device_available);
 870         /* For success case, the suspend path will release the lock */
 871  Unlock:
 872         mutex_unlock(&pm_mutex);
 873         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 874         return error;
 875  Close_Finish:
 876         swsusp_close(FMODE_READ);
 877         goto Finish;
 878 }
 879
 880 late_initcall_sync(software_resume);
 881
 882
 883 static const char * const hibernation_modes[] = {
 884         [HIBERNATION_PLATFORM]  = "platform",
 885         [HIBERNATION_SHUTDOWN]  = "shutdown",
 886         [HIBERNATION_REBOOT]    = "reboot",
 887 #ifdef CONFIG_SUSPEND
 888         [HIBERNATION_SUSPEND]   = "suspend",
 889 #endif
 890 };
 891
 892 /*
 893  * /sys/power/disk - Control hibernation mode.
 894  *
 895  * Hibernation can be handled in several ways.  There are a few different ways
 896  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 897  * or other hibernation_ops), powering it off or rebooting it (for testing
 898  * mostly).
 899  *
 900  * The sysfs file /sys/power/disk provides an interface for selecting the
 901  * hibernation mode to use.  Reading from this file causes the available modes
 902  * to be printed.  There are 3 modes that can be supported:
 903  *
 904  *      'platform'
 905  *      'shutdown'
 906  *      'reboot'
 907  *
 908  * If a platform hibernation driver is in use, 'platform' will be supported
 909  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 910  * The selected option (i.e. the one corresponding to the current value of
 911  * hibernation_mode) is enclosed by a square bracket.
 912  *
 913  * To select a given hibernation mode it is necessary to write the mode's
 914  * string representation (as returned by reading from /sys/power/disk) back
 915  * into /sys/power/disk.
 916  */
 917
 918 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 919                          char *buf)
 920 {
 921         int i;
 922         char *start = buf;
 923
 924         if (!hibernation_available())
 925                 return sprintf(buf, "[disabled]\n");
 926
 927         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 928                 if (!hibernation_modes[i])
 929                         continue;
 930                 switch (i) {
 931                 case HIBERNATION_SHUTDOWN:
 932                 case HIBERNATION_REBOOT:
 933 #ifdef CONFIG_SUSPEND
 934                 case HIBERNATION_SUSPEND:
 935 #endif
 936                         break;
 937                 case HIBERNATION_PLATFORM:
 938                         if (hibernation_ops)
 939                                 break;
 940                         /* not a valid mode, continue with loop */
 941                         continue;
 942                 }
 943                 if (i == hibernation_mode)
 944                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 945                 else
 946                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 947         }
 948         buf += sprintf(buf, "\n");
 949         return buf-start;
 950 }
 951
 952 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 953                           const char *buf, size_t n)
 954 {
 955         int error = 0;
 956         int i;
 957         int len;
 958         char *p;
 959         int mode = HIBERNATION_INVALID;
 960
 961         if (!hibernation_available())
 962                 return -EPERM;
 963
 964         p = memchr(buf, '\n', n);
 965         len = p ? p - buf : n;
 966
 967         lock_system_sleep();
 968         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 969                 if (len == strlen(hibernation_modes[i])
 970                     && !strncmp(buf, hibernation_modes[i], len)) {
 971                         mode = i;
 972                         break;
 973                 }
 974         }
 975         if (mode != HIBERNATION_INVALID) {
 976                 switch (mode) {
 977                 case HIBERNATION_SHUTDOWN:
 978                 case HIBERNATION_REBOOT:
 979 #ifdef CONFIG_SUSPEND
 980                 case HIBERNATION_SUSPEND:
 981 #endif
 982                         hibernation_mode = mode;
 983                         break;
 984                 case HIBERNATION_PLATFORM:
 985                         if (hibernation_ops)
 986                                 hibernation_mode = mode;
 987                         else
 988                                 error = -EINVAL;
 989                 }
 990         } else
 991                 error = -EINVAL;
 992
 993         if (!error)
 994                 pr_debug("PM: Hibernation mode set to '%s'\n",
 995                          hibernation_modes[mode]);
 996         unlock_system_sleep();
 997         return error ? error : n;
 998 }
 999
1000 power_attr(disk);
1001
1002 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1003                            char *buf)
1004 {
1005         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1006                        MINOR(swsusp_resume_device));
1007 }
1008
1009 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1010                             const char *buf, size_t n)
1011 {
1012         dev_t res;
1013         int len = n;
1014         char *name;
1015
1016         if (len && buf[len-1] == '\n')
1017                 len--;
1018         name = kstrndup(buf, len, GFP_KERNEL);
1019         if (!name)
1020                 return -ENOMEM;
1021
1022         res = name_to_dev_t(name);
1023         kfree(name);
1024         if (!res)
1025                 return -EINVAL;
1026
1027         lock_system_sleep();
1028         swsusp_resume_device = res;
1029         unlock_system_sleep();
1030         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1031         noresume = 0;
1032         software_resume();
1033         return n;
1034 }
1035
1036 power_attr(resume);
1037
1038 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1039                                char *buf)
1040 {
1041         return sprintf(buf, "%lu\n", image_size);
1042 }
1043
1044 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1045                                 const char *buf, size_t n)
1046 {
1047         unsigned long size;
1048
1049         if (sscanf(buf, "%lu", &size) == 1) {
1050                 image_size = size;
1051                 return n;
1052         }
1053
1054         return -EINVAL;
1055 }
1056
1057 power_attr(image_size);
1058
1059 static ssize_t reserved_size_show(struct kobject *kobj,
1060                                   struct kobj_attribute *attr, char *buf)
1061 {
1062         return sprintf(buf, "%lu\n", reserved_size);
1063 }
1064
1065 static ssize_t reserved_size_store(struct kobject *kobj,
1066                                    struct kobj_attribute *attr,
1067                                    const char *buf, size_t n)
1068 {
1069         unsigned long size;
1070
1071         if (sscanf(buf, "%lu", &size) == 1) {
1072                 reserved_size = size;
1073                 return n;
1074         }
1075
1076         return -EINVAL;
1077 }
1078
1079 power_attr(reserved_size);
1080
1081 static struct attribute * g[] = {
1082         &disk_attr.attr,
1083         &resume_attr.attr,
1084         &image_size_attr.attr,
1085         &reserved_size_attr.attr,
1086         NULL,
1087 };
1088
1089
1090 static struct attribute_group attr_group = {
1091         .attrs = g,
1092 };
1093
1094
1095 static int __init pm_disk_init(void)
1096 {
1097         return sysfs_create_group(power_kobj, &attr_group);
1098 }
1099
1100 core_initcall(pm_disk_init);
1101
1102
1103 static int __init resume_setup(char *str)
1104 {
1105         if (noresume)
1106                 return 1;
1107
1108         strncpy( resume_file, str, 255 );
1109         return 1;
1110 }
1111
1112 static int __init resume_offset_setup(char *str)
1113 {
1114         unsigned long long offset;
1115
1116         if (noresume)
1117                 return 1;
1118
1119         if (sscanf(str, "%llu", &offset) == 1)
1120                 swsusp_resume_block = offset;
1121
1122         return 1;
1123 }
1124
1125 static int __init hibernate_setup(char *str)
1126 {
1127         if (!strncmp(str, "noresume", 8)) {
1128                 noresume = 1;
1129         } else if (!strncmp(str, "nocompress", 10)) {
1130                 nocompress = 1;
1131         } else if (!strncmp(str, "no", 2)) {
1132                 noresume = 1;
1133                 nohibernate = 1;
1134         } else if (IS_ENABLED(CONFIG_DEBUG_RODATA)
1135                    && !strncmp(str, "protect_image", 13)) {
1136                 enable_restore_image_protection();
1137         }
1138         return 1;
1139 }
1140
1141 static int __init noresume_setup(char *str)
1142 {
1143         noresume = 1;
1144         return 1;
1145 }
1146
1147 static int __init resumewait_setup(char *str)
1148 {
1149         resume_wait = 1;
1150         return 1;
1151 }
1152
1153 static int __init resumedelay_setup(char *str)
1154 {
1155         int rc = kstrtouint(str, 0, &resume_delay);
1156
1157         if (rc)
1158                 return rc;
1159         return 1;
1160 }
1161
1162 static int __init nohibernate_setup(char *str)
1163 {
1164         noresume = 1;
1165         nohibernate = 1;
1166         return 1;
1167 }
1168
1169 static int __init kaslr_nohibernate_setup(char *str)
1170 {
1171         return nohibernate_setup(str);
1172 }
1173
1174 static int __init page_poison_nohibernate_setup(char *str)
1175 {
1176 #ifdef CONFIG_PAGE_POISONING_ZERO
1177         /*
1178          * The zeroing option for page poison skips the checks on alloc.
1179          * since hibernation doesn't save free pages there's no way to
1180          * guarantee the pages will still be zeroed.
1181          */
1182         if (!strcmp(str, "on")) {
1183                 pr_info("Disabling hibernation due to page poisoning\n");
1184                 return nohibernate_setup(str);
1185         }
1186 #endif
1187         return 1;
1188 }
1189
1190 __setup("noresume", noresume_setup);
1191 __setup("resume_offset=", resume_offset_setup);
1192 __setup("resume=", resume_setup);
1193 __setup("hibernate=", hibernate_setup);
1194 __setup("resumewait", resumewait_setup);
1195 __setup("resumedelay=", resumedelay_setup);
1196 __setup("nohibernate", nohibernate_setup);
1197 __setup("kaslr", kaslr_nohibernate_setup);
1198 __setup("page_poison=", page_poison_nohibernate_setup);