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 #define pr_fmt(fmt) "PM: " fmt
  14
  15 #include <linux/export.h>
  16 #include <linux/suspend.h>
  17 #include <linux/reboot.h>
  18 #include <linux/string.h>
  19 #include <linux/device.h>
  20 #include <linux/async.h>
  21 #include <linux/delay.h>
  22 #include <linux/fs.h>
  23 #include <linux/mount.h>
  24 #include <linux/pm.h>
  25 #include <linux/nmi.h>
  26 #include <linux/console.h>
  27 #include <linux/cpu.h>
  28 #include <linux/freezer.h>
  29 #include <linux/gfp.h>
  30 #include <linux/syscore_ops.h>
  31 #include <linux/ctype.h>
  32 #include <linux/genhd.h>
  33 #include <linux/ktime.h>
  34 #include <trace/events/power.h>
  35
  36 #include "power.h"
  37
  38
  39 static int nocompress;
  40 static int noresume;
  41 static int nohibernate;
  42 static int resume_wait;
  43 static unsigned int resume_delay;
  44 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  45 dev_t swsusp_resume_device;
  46 sector_t swsusp_resume_block;
  47 __visible int in_suspend __nosavedata;
  48
  49 enum {
  50         HIBERNATION_INVALID,
  51         HIBERNATION_PLATFORM,
  52         HIBERNATION_SHUTDOWN,
  53         HIBERNATION_REBOOT,
  54 #ifdef CONFIG_SUSPEND
  55         HIBERNATION_SUSPEND,
  56 #endif
  57         HIBERNATION_TEST_RESUME,
  58         /* keep last */
  59         __HIBERNATION_AFTER_LAST
  60 };
  61 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  62 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  63
  64 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  65
  66 bool freezer_test_done;
  67
  68 static const struct platform_hibernation_ops *hibernation_ops;
  69
  70 bool hibernation_available(void)
  71 {
  72         return (nohibernate == 0);
  73 }
  74
  75 /**
  76  * hibernation_set_ops - Set the global hibernate operations.
  77  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  78  */
  79 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  80 {
  81         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  82             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  83             && ops->restore_cleanup && ops->leave)) {
  84                 WARN_ON(1);
  85                 return;
  86         }
  87         lock_system_sleep();
  88         hibernation_ops = ops;
  89         if (ops)
  90                 hibernation_mode = HIBERNATION_PLATFORM;
  91         else if (hibernation_mode == HIBERNATION_PLATFORM)
  92                 hibernation_mode = HIBERNATION_SHUTDOWN;
  93
  94         unlock_system_sleep();
  95 }
  96 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  97
  98 static bool entering_platform_hibernation;
  99
 100 bool system_entering_hibernation(void)
 101 {
 102         return entering_platform_hibernation;
 103 }
 104 EXPORT_SYMBOL(system_entering_hibernation);
 105
 106 #ifdef CONFIG_PM_DEBUG
 107 static void hibernation_debug_sleep(void)
 108 {
 109         pr_info("hibernation debug: Waiting for 5 seconds.\n");
 110         mdelay(5000);
 111 }
 112
 113 static int hibernation_test(int level)
 114 {
 115         if (pm_test_level == level) {
 116                 hibernation_debug_sleep();
 117                 return 1;
 118         }
 119         return 0;
 120 }
 121 #else /* !CONFIG_PM_DEBUG */
 122 static int hibernation_test(int level) { return 0; }
 123 #endif /* !CONFIG_PM_DEBUG */
 124
 125 /**
 126  * platform_begin - Call platform to start hibernation.
 127  * @platform_mode: Whether or not to use the platform driver.
 128  */
 129 static int platform_begin(int platform_mode)
 130 {
 131         return (platform_mode && hibernation_ops) ?
 132                 hibernation_ops->begin() : 0;
 133 }
 134
 135 /**
 136  * platform_end - Call platform to finish transition to the working state.
 137  * @platform_mode: Whether or not to use the platform driver.
 138  */
 139 static void platform_end(int platform_mode)
 140 {
 141         if (platform_mode && hibernation_ops)
 142                 hibernation_ops->end();
 143 }
 144
 145 /**
 146  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 147  * @platform_mode: Whether or not to use the platform driver.
 148  *
 149  * Use the platform driver to prepare the system for creating a hibernate image,
 150  * if so configured, and return an error code if that fails.
 151  */
 152
 153 static int platform_pre_snapshot(int platform_mode)
 154 {
 155         return (platform_mode && hibernation_ops) ?
 156                 hibernation_ops->pre_snapshot() : 0;
 157 }
 158
 159 /**
 160  * platform_leave - Call platform to prepare a transition to the working state.
 161  * @platform_mode: Whether or not to use the platform driver.
 162  *
 163  * Use the platform driver prepare to prepare the machine for switching to the
 164  * normal mode of operation.
 165  *
 166  * This routine is called on one CPU with interrupts disabled.
 167  */
 168 static void platform_leave(int platform_mode)
 169 {
 170         if (platform_mode && hibernation_ops)
 171                 hibernation_ops->leave();
 172 }
 173
 174 /**
 175  * platform_finish - Call platform to switch the system to the working state.
 176  * @platform_mode: Whether or not to use the platform driver.
 177  *
 178  * Use the platform driver to switch the machine to the normal mode of
 179  * operation.
 180  *
 181  * This routine must be called after platform_prepare().
 182  */
 183 static void platform_finish(int platform_mode)
 184 {
 185         if (platform_mode && hibernation_ops)
 186                 hibernation_ops->finish();
 187 }
 188
 189 /**
 190  * platform_pre_restore - Prepare for hibernate image restoration.
 191  * @platform_mode: Whether or not to use the platform driver.
 192  *
 193  * Use the platform driver to prepare the system for resume from a hibernation
 194  * image.
 195  *
 196  * If the restore fails after this function has been called,
 197  * platform_restore_cleanup() must be called.
 198  */
 199 static int platform_pre_restore(int platform_mode)
 200 {
 201         return (platform_mode && hibernation_ops) ?
 202                 hibernation_ops->pre_restore() : 0;
 203 }
 204
 205 /**
 206  * platform_restore_cleanup - Switch to the working state after failing restore.
 207  * @platform_mode: Whether or not to use the platform driver.
 208  *
 209  * Use the platform driver to switch the system to the normal mode of operation
 210  * after a failing restore.
 211  *
 212  * If platform_pre_restore() has been called before the failing restore, this
 213  * function must be called too, regardless of the result of
 214  * platform_pre_restore().
 215  */
 216 static void platform_restore_cleanup(int platform_mode)
 217 {
 218         if (platform_mode && hibernation_ops)
 219                 hibernation_ops->restore_cleanup();
 220 }
 221
 222 /**
 223  * platform_recover - Recover from a failure to suspend devices.
 224  * @platform_mode: Whether or not to use the platform driver.
 225  */
 226 static void platform_recover(int platform_mode)
 227 {
 228         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 229                 hibernation_ops->recover();
 230 }
 231
 232 /**
 233  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 234  * @start: Starting event.
 235  * @stop: Final event.
 236  * @nr_pages: Number of memory pages processed between @start and @stop.
 237  * @msg: Additional diagnostic message to print.
 238  */
 239 void swsusp_show_speed(ktime_t start, ktime_t stop,
 240                       unsigned nr_pages, char *msg)
 241 {
 242         ktime_t diff;
 243         u64 elapsed_centisecs64;
 244         unsigned int centisecs;
 245         unsigned int k;
 246         unsigned int kps;
 247
 248         diff = ktime_sub(stop, start);
 249         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 250         centisecs = elapsed_centisecs64;
 251         if (centisecs == 0)
 252                 centisecs = 1;  /* avoid div-by-zero */
 253         k = nr_pages * (PAGE_SIZE / 1024);
 254         kps = (k * 100) / centisecs;
 255         pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 256                 msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 257                 (kps % 1000) / 10);
 258 }
 259
 260 /**
 261  * create_image - Create a hibernation image.
 262  * @platform_mode: Whether or not to use the platform driver.
 263  *
 264  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 265  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 266  *
 267  * Control reappears in this routine after the subsequent restore.
 268  */
 269 static int create_image(int platform_mode)
 270 {
 271         int error;
 272
 273         error = dpm_suspend_end(PMSG_FREEZE);
 274         if (error) {
 275                 pr_err("Some devices failed to power down, 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 = suspend_disable_secondary_cpus();
 284         if (error || hibernation_test(TEST_CPUS))
 285                 goto Enable_cpus;
 286
 287         local_irq_disable();
 288
 289         system_state = SYSTEM_SUSPEND;
 290
 291         error = syscore_suspend();
 292         if (error) {
 293                 pr_err("Some system devices failed to power down, aborting hibernation\n");
 294                 goto Enable_irqs;
 295         }
 296
 297         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 298                 goto Power_up;
 299
 300         in_suspend = 1;
 301         save_processor_state();
 302         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 303         error = swsusp_arch_suspend();
 304         /* Restore control flow magically appears here */
 305         restore_processor_state();
 306         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 307         if (error)
 308                 pr_err("Error %d creating hibernation image\n", error);
 309
 310         if (!in_suspend) {
 311                 events_check_enabled = false;
 312                 clear_free_pages();
 313         }
 314
 315         platform_leave(platform_mode);
 316
 317  Power_up:
 318         syscore_resume();
 319
 320  Enable_irqs:
 321         system_state = SYSTEM_RUNNING;
 322         local_irq_enable();
 323
 324  Enable_cpus:
 325         suspend_enable_secondary_cpus();
 326
 327  Platform_finish:
 328         platform_finish(platform_mode);
 329
 330         dpm_resume_start(in_suspend ?
 331                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 332
 333         return error;
 334 }
 335
 336 /**
 337  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 338  * @platform_mode: If set, use platform driver to prepare for the transition.
 339  *
 340  * This routine must be called with system_transition_mutex held.
 341  */
 342 int hibernation_snapshot(int platform_mode)
 343 {
 344         pm_message_t msg;
 345         int error;
 346
 347         pm_suspend_clear_flags();
 348         error = platform_begin(platform_mode);
 349         if (error)
 350                 goto Close;
 351
 352         /* Preallocate image memory before shutting down devices. */
 353         error = hibernate_preallocate_memory();
 354         if (error)
 355                 goto Close;
 356
 357         error = freeze_kernel_threads();
 358         if (error)
 359                 goto Cleanup;
 360
 361         if (hibernation_test(TEST_FREEZER)) {
 362
 363                 /*
 364                  * Indicate to the caller that we are returning due to a
 365                  * successful freezer test.
 366                  */
 367                 freezer_test_done = true;
 368                 goto Thaw;
 369         }
 370
 371         error = dpm_prepare(PMSG_FREEZE);
 372         if (error) {
 373                 dpm_complete(PMSG_RECOVER);
 374                 goto Thaw;
 375         }
 376
 377         suspend_console();
 378         pm_restrict_gfp_mask();
 379
 380         error = dpm_suspend(PMSG_FREEZE);
 381
 382         if (error || hibernation_test(TEST_DEVICES))
 383                 platform_recover(platform_mode);
 384         else
 385                 error = create_image(platform_mode);
 386
 387         /*
 388          * In the case that we call create_image() above, the control
 389          * returns here (1) after the image has been created or the
 390          * image creation has failed and (2) after a successful restore.
 391          */
 392
 393         /* We may need to release the preallocated image pages here. */
 394         if (error || !in_suspend)
 395                 swsusp_free();
 396
 397         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 398         dpm_resume(msg);
 399
 400         if (error || !in_suspend)
 401                 pm_restore_gfp_mask();
 402
 403         resume_console();
 404         dpm_complete(msg);
 405
 406  Close:
 407         platform_end(platform_mode);
 408         return error;
 409
 410  Thaw:
 411         thaw_kernel_threads();
 412  Cleanup:
 413         swsusp_free();
 414         goto Close;
 415 }
 416
 417 int __weak hibernate_resume_nonboot_cpu_disable(void)
 418 {
 419         return suspend_disable_secondary_cpus();
 420 }
 421
 422 /**
 423  * resume_target_kernel - Restore system state from a hibernation image.
 424  * @platform_mode: Whether or not to use the platform driver.
 425  *
 426  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 427  * contents of highmem that have not been restored yet from the image and run
 428  * the low-level code that will restore the remaining contents of memory and
 429  * switch to the just restored target kernel.
 430  */
 431 static int resume_target_kernel(bool platform_mode)
 432 {
 433         int error;
 434
 435         error = dpm_suspend_end(PMSG_QUIESCE);
 436         if (error) {
 437                 pr_err("Some devices failed to power down, aborting resume\n");
 438                 return error;
 439         }
 440
 441         error = platform_pre_restore(platform_mode);
 442         if (error)
 443                 goto Cleanup;
 444
 445         error = hibernate_resume_nonboot_cpu_disable();
 446         if (error)
 447                 goto Enable_cpus;
 448
 449         local_irq_disable();
 450         system_state = SYSTEM_SUSPEND;
 451
 452         error = syscore_suspend();
 453         if (error)
 454                 goto Enable_irqs;
 455
 456         save_processor_state();
 457         error = restore_highmem();
 458         if (!error) {
 459                 error = swsusp_arch_resume();
 460                 /*
 461                  * The code below is only ever reached in case of a failure.
 462                  * Otherwise, execution continues at the place where
 463                  * swsusp_arch_suspend() was called.
 464                  */
 465                 BUG_ON(!error);
 466                 /*
 467                  * This call to restore_highmem() reverts the changes made by
 468                  * the previous one.
 469                  */
 470                 restore_highmem();
 471         }
 472         /*
 473          * The only reason why swsusp_arch_resume() can fail is memory being
 474          * very tight, so we have to free it as soon as we can to avoid
 475          * subsequent failures.
 476          */
 477         swsusp_free();
 478         restore_processor_state();
 479         touch_softlockup_watchdog();
 480
 481         syscore_resume();
 482
 483  Enable_irqs:
 484         system_state = SYSTEM_RUNNING;
 485         local_irq_enable();
 486
 487  Enable_cpus:
 488         suspend_enable_secondary_cpus();
 489
 490  Cleanup:
 491         platform_restore_cleanup(platform_mode);
 492
 493         dpm_resume_start(PMSG_RECOVER);
 494
 495         return error;
 496 }
 497
 498 /**
 499  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 500  * @platform_mode: If set, use platform driver to prepare for the transition.
 501  *
 502  * This routine must be called with system_transition_mutex held.  If it is
 503  * successful, control reappears in the restored target kernel in
 504  * hibernation_snapshot().
 505  */
 506 int hibernation_restore(int platform_mode)
 507 {
 508         int error;
 509
 510         pm_prepare_console();
 511         suspend_console();
 512         pm_restrict_gfp_mask();
 513         error = dpm_suspend_start(PMSG_QUIESCE);
 514         if (!error) {
 515                 error = resume_target_kernel(platform_mode);
 516                 /*
 517                  * The above should either succeed and jump to the new kernel,
 518                  * or return with an error. Otherwise things are just
 519                  * undefined, so let's be paranoid.
 520                  */
 521                 BUG_ON(!error);
 522         }
 523         dpm_resume_end(PMSG_RECOVER);
 524         pm_restore_gfp_mask();
 525         resume_console();
 526         pm_restore_console();
 527         return error;
 528 }
 529
 530 /**
 531  * hibernation_platform_enter - Power off the system using the platform driver.
 532  */
 533 int hibernation_platform_enter(void)
 534 {
 535         int error;
 536
 537         if (!hibernation_ops)
 538                 return -ENOSYS;
 539
 540         /*
 541          * We have cancelled the power transition by running
 542          * hibernation_ops->finish() before saving the image, so we should let
 543          * the firmware know that we're going to enter the sleep state after all
 544          */
 545         error = hibernation_ops->begin();
 546         if (error)
 547                 goto Close;
 548
 549         entering_platform_hibernation = true;
 550         suspend_console();
 551         error = dpm_suspend_start(PMSG_HIBERNATE);
 552         if (error) {
 553                 if (hibernation_ops->recover)
 554                         hibernation_ops->recover();
 555                 goto Resume_devices;
 556         }
 557
 558         error = dpm_suspend_end(PMSG_HIBERNATE);
 559         if (error)
 560                 goto Resume_devices;
 561
 562         error = hibernation_ops->prepare();
 563         if (error)
 564                 goto Platform_finish;
 565
 566         error = suspend_disable_secondary_cpus();
 567         if (error)
 568                 goto Enable_cpus;
 569
 570         local_irq_disable();
 571         system_state = SYSTEM_SUSPEND;
 572         syscore_suspend();
 573         if (pm_wakeup_pending()) {
 574                 error = -EAGAIN;
 575                 goto Power_up;
 576         }
 577
 578         hibernation_ops->enter();
 579         /* We should never get here */
 580         while (1);
 581
 582  Power_up:
 583         syscore_resume();
 584         system_state = SYSTEM_RUNNING;
 585         local_irq_enable();
 586
 587  Enable_cpus:
 588         suspend_enable_secondary_cpus();
 589
 590  Platform_finish:
 591         hibernation_ops->finish();
 592
 593         dpm_resume_start(PMSG_RESTORE);
 594
 595  Resume_devices:
 596         entering_platform_hibernation = false;
 597         dpm_resume_end(PMSG_RESTORE);
 598         resume_console();
 599
 600  Close:
 601         hibernation_ops->end();
 602
 603         return error;
 604 }
 605
 606 /**
 607  * power_down - Shut the machine down for hibernation.
 608  *
 609  * Use the platform driver, if configured, to put the system into the sleep
 610  * state corresponding to hibernation, or try to power it off or reboot,
 611  * depending on the value of hibernation_mode.
 612  */
 613 static void power_down(void)
 614 {
 615 #ifdef CONFIG_SUSPEND
 616         int error;
 617
 618         if (hibernation_mode == HIBERNATION_SUSPEND) {
 619                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 620                 if (error) {
 621                         hibernation_mode = hibernation_ops ?
 622                                                 HIBERNATION_PLATFORM :
 623                                                 HIBERNATION_SHUTDOWN;
 624                 } else {
 625                         /* Restore swap signature. */
 626                         error = swsusp_unmark();
 627                         if (error)
 628                                 pr_err("Swap will be unusable! Try swapon -a.\n");
 629
 630                         return;
 631                 }
 632         }
 633 #endif
 634
 635         switch (hibernation_mode) {
 636         case HIBERNATION_REBOOT:
 637                 kernel_restart(NULL);
 638                 break;
 639         case HIBERNATION_PLATFORM:
 640                 hibernation_platform_enter();
 641                 /* Fall through */
 642         case HIBERNATION_SHUTDOWN:
 643                 if (pm_power_off)
 644                         kernel_power_off();
 645                 break;
 646         }
 647         kernel_halt();
 648         /*
 649          * Valid image is on the disk, if we continue we risk serious data
 650          * corruption after resume.
 651          */
 652         pr_crit("Power down manually\n");
 653         while (1)
 654                 cpu_relax();
 655 }
 656
 657 static int load_image_and_restore(void)
 658 {
 659         int error;
 660         unsigned int flags;
 661
 662         pm_pr_dbg("Loading hibernation image.\n");
 663
 664         lock_device_hotplug();
 665         error = create_basic_memory_bitmaps();
 666         if (error)
 667                 goto Unlock;
 668
 669         error = swsusp_read(&flags);
 670         swsusp_close(FMODE_READ);
 671         if (!error)
 672                 hibernation_restore(flags & SF_PLATFORM_MODE);
 673
 674         pr_err("Failed to load hibernation image, recovering.\n");
 675         swsusp_free();
 676         free_basic_memory_bitmaps();
 677  Unlock:
 678         unlock_device_hotplug();
 679
 680         return error;
 681 }
 682
 683 /**
 684  * hibernate - Carry out system hibernation, including saving the image.
 685  */
 686 int hibernate(void)
 687 {
 688         int error, nr_calls = 0;
 689         bool snapshot_test = false;
 690
 691         if (!hibernation_available()) {
 692                 pm_pr_dbg("Hibernation not available.\n");
 693                 return -EPERM;
 694         }
 695
 696         lock_system_sleep();
 697         /* The snapshot device should not be opened while we're running */
 698         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 699                 error = -EBUSY;
 700                 goto Unlock;
 701         }
 702
 703         pr_info("hibernation entry\n");
 704         pm_prepare_console();
 705         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 706         if (error) {
 707                 nr_calls--;
 708                 goto Exit;
 709         }
 710
 711         ksys_sync_helper();
 712
 713         error = freeze_processes();
 714         if (error)
 715                 goto Exit;
 716
 717         lock_device_hotplug();
 718         /* Allocate memory management structures */
 719         error = create_basic_memory_bitmaps();
 720         if (error)
 721                 goto Thaw;
 722
 723         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 724         if (error || freezer_test_done)
 725                 goto Free_bitmaps;
 726
 727         if (in_suspend) {
 728                 unsigned int flags = 0;
 729
 730                 if (hibernation_mode == HIBERNATION_PLATFORM)
 731                         flags |= SF_PLATFORM_MODE;
 732                 if (nocompress)
 733                         flags |= SF_NOCOMPRESS_MODE;
 734                 else
 735                         flags |= SF_CRC32_MODE;
 736
 737                 pm_pr_dbg("Writing image.\n");
 738                 error = swsusp_write(flags);
 739                 swsusp_free();
 740                 if (!error) {
 741                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 742                                 snapshot_test = true;
 743                         else
 744                                 power_down();
 745                 }
 746                 in_suspend = 0;
 747                 pm_restore_gfp_mask();
 748         } else {
 749                 pm_pr_dbg("Image restored successfully.\n");
 750         }
 751
 752  Free_bitmaps:
 753         free_basic_memory_bitmaps();
 754  Thaw:
 755         unlock_device_hotplug();
 756         if (snapshot_test) {
 757                 pm_pr_dbg("Checking hibernation image\n");
 758                 error = swsusp_check();
 759                 if (!error)
 760                         error = load_image_and_restore();
 761         }
 762         thaw_processes();
 763
 764         /* Don't bother checking whether freezer_test_done is true */
 765         freezer_test_done = false;
 766  Exit:
 767         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 768         pm_restore_console();
 769         atomic_inc(&snapshot_device_available);
 770  Unlock:
 771         unlock_system_sleep();
 772         pr_info("hibernation exit\n");
 773
 774         return error;
 775 }
 776
 777
 778 /**
 779  * software_resume - Resume from a saved hibernation image.
 780  *
 781  * This routine is called as a late initcall, when all devices have been
 782  * discovered and initialized already.
 783  *
 784  * The image reading code is called to see if there is a hibernation image
 785  * available for reading.  If that is the case, devices are quiesced and the
 786  * contents of memory is restored from the saved image.
 787  *
 788  * If this is successful, control reappears in the restored target kernel in
 789  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 790  * attempts to recover gracefully and make the kernel return to the normal mode
 791  * of operation.
 792  */
 793 static int software_resume(void)
 794 {
 795         int error, nr_calls = 0;
 796
 797         /*
 798          * If the user said "noresume".. bail out early.
 799          */
 800         if (noresume || !hibernation_available())
 801                 return 0;
 802
 803         /*
 804          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 805          * is configured into the kernel. Since the regular hibernate
 806          * trigger path is via sysfs which takes a buffer mutex before
 807          * calling hibernate functions (which take system_transition_mutex)
 808          * this can cause lockdep to complain about a possible ABBA deadlock
 809          * which cannot happen since we're in the boot code here and
 810          * sysfs can't be invoked yet. Therefore, we use a subclass
 811          * here to avoid lockdep complaining.
 812          */
 813         mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 814
 815         if (swsusp_resume_device)
 816                 goto Check_image;
 817
 818         if (!strlen(resume_file)) {
 819                 error = -ENOENT;
 820                 goto Unlock;
 821         }
 822
 823         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 824
 825         if (resume_delay) {
 826                 pr_info("Waiting %dsec before reading resume device ...\n",
 827                         resume_delay);
 828                 ssleep(resume_delay);
 829         }
 830
 831         /* Check if the device is there */
 832         swsusp_resume_device = name_to_dev_t(resume_file);
 833
 834         /*
 835          * name_to_dev_t is ineffective to verify parition if resume_file is in
 836          * integer format. (e.g. major:minor)
 837          */
 838         if (isdigit(resume_file[0]) && resume_wait) {
 839                 int partno;
 840                 while (!get_gendisk(swsusp_resume_device, &partno))
 841                         msleep(10);
 842         }
 843
 844         if (!swsusp_resume_device) {
 845                 /*
 846                  * Some device discovery might still be in progress; we need
 847                  * to wait for this to finish.
 848                  */
 849                 wait_for_device_probe();
 850
 851                 if (resume_wait) {
 852                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 853                                 msleep(10);
 854                         async_synchronize_full();
 855                 }
 856
 857                 swsusp_resume_device = name_to_dev_t(resume_file);
 858                 if (!swsusp_resume_device) {
 859                         error = -ENODEV;
 860                         goto Unlock;
 861                 }
 862         }
 863
 864  Check_image:
 865         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 866                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 867
 868         pm_pr_dbg("Looking for hibernation image.\n");
 869         error = swsusp_check();
 870         if (error)
 871                 goto Unlock;
 872
 873         /* The snapshot device should not be opened while we're running */
 874         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 875                 error = -EBUSY;
 876                 swsusp_close(FMODE_READ);
 877                 goto Unlock;
 878         }
 879
 880         pr_info("resume from hibernation\n");
 881         pm_prepare_console();
 882         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 883         if (error) {
 884                 nr_calls--;
 885                 goto Close_Finish;
 886         }
 887
 888         pm_pr_dbg("Preparing processes for restore.\n");
 889         error = freeze_processes();
 890         if (error)
 891                 goto Close_Finish;
 892         error = load_image_and_restore();
 893         thaw_processes();
 894  Finish:
 895         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 896         pm_restore_console();
 897         pr_info("resume from hibernation failed (%d)\n", error);
 898         atomic_inc(&snapshot_device_available);
 899         /* For success case, the suspend path will release the lock */
 900  Unlock:
 901         mutex_unlock(&system_transition_mutex);
 902         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 903         return error;
 904  Close_Finish:
 905         swsusp_close(FMODE_READ);
 906         goto Finish;
 907 }
 908
 909 late_initcall_sync(software_resume);
 910
 911
 912 static const char * const hibernation_modes[] = {
 913         [HIBERNATION_PLATFORM]  = "platform",
 914         [HIBERNATION_SHUTDOWN]  = "shutdown",
 915         [HIBERNATION_REBOOT]    = "reboot",
 916 #ifdef CONFIG_SUSPEND
 917         [HIBERNATION_SUSPEND]   = "suspend",
 918 #endif
 919         [HIBERNATION_TEST_RESUME]       = "test_resume",
 920 };
 921
 922 /*
 923  * /sys/power/disk - Control hibernation mode.
 924  *
 925  * Hibernation can be handled in several ways.  There are a few different ways
 926  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 927  * or other hibernation_ops), powering it off or rebooting it (for testing
 928  * mostly).
 929  *
 930  * The sysfs file /sys/power/disk provides an interface for selecting the
 931  * hibernation mode to use.  Reading from this file causes the available modes
 932  * to be printed.  There are 3 modes that can be supported:
 933  *
 934  *      'platform'
 935  *      'shutdown'
 936  *      'reboot'
 937  *
 938  * If a platform hibernation driver is in use, 'platform' will be supported
 939  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 940  * The selected option (i.e. the one corresponding to the current value of
 941  * hibernation_mode) is enclosed by a square bracket.
 942  *
 943  * To select a given hibernation mode it is necessary to write the mode's
 944  * string representation (as returned by reading from /sys/power/disk) back
 945  * into /sys/power/disk.
 946  */
 947
 948 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 949                          char *buf)
 950 {
 951         int i;
 952         char *start = buf;
 953
 954         if (!hibernation_available())
 955                 return sprintf(buf, "[disabled]\n");
 956
 957         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 958                 if (!hibernation_modes[i])
 959                         continue;
 960                 switch (i) {
 961                 case HIBERNATION_SHUTDOWN:
 962                 case HIBERNATION_REBOOT:
 963 #ifdef CONFIG_SUSPEND
 964                 case HIBERNATION_SUSPEND:
 965 #endif
 966                 case HIBERNATION_TEST_RESUME:
 967                         break;
 968                 case HIBERNATION_PLATFORM:
 969                         if (hibernation_ops)
 970                                 break;
 971                         /* not a valid mode, continue with loop */
 972                         continue;
 973                 }
 974                 if (i == hibernation_mode)
 975                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 976                 else
 977                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 978         }
 979         buf += sprintf(buf, "\n");
 980         return buf-start;
 981 }
 982
 983 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 984                           const char *buf, size_t n)
 985 {
 986         int error = 0;
 987         int i;
 988         int len;
 989         char *p;
 990         int mode = HIBERNATION_INVALID;
 991
 992         if (!hibernation_available())
 993                 return -EPERM;
 994
 995         p = memchr(buf, '\n', n);
 996         len = p ? p - buf : n;
 997
 998         lock_system_sleep();
 999         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1000                 if (len == strlen(hibernation_modes[i])
1001                     && !strncmp(buf, hibernation_modes[i], len)) {
1002                         mode = i;
1003                         break;
1004                 }
1005         }
1006         if (mode != HIBERNATION_INVALID) {
1007                 switch (mode) {
1008                 case HIBERNATION_SHUTDOWN:
1009                 case HIBERNATION_REBOOT:
1010 #ifdef CONFIG_SUSPEND
1011                 case HIBERNATION_SUSPEND:
1012 #endif
1013                 case HIBERNATION_TEST_RESUME:
1014                         hibernation_mode = mode;
1015                         break;
1016                 case HIBERNATION_PLATFORM:
1017                         if (hibernation_ops)
1018                                 hibernation_mode = mode;
1019                         else
1020                                 error = -EINVAL;
1021                 }
1022         } else
1023                 error = -EINVAL;
1024
1025         if (!error)
1026                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1027                                hibernation_modes[mode]);
1028         unlock_system_sleep();
1029         return error ? error : n;
1030 }
1031
1032 power_attr(disk);
1033
1034 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1035                            char *buf)
1036 {
1037         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1038                        MINOR(swsusp_resume_device));
1039 }
1040
1041 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1042                             const char *buf, size_t n)
1043 {
1044         dev_t res;
1045         int len = n;
1046         char *name;
1047
1048         if (len && buf[len-1] == '\n')
1049                 len--;
1050         name = kstrndup(buf, len, GFP_KERNEL);
1051         if (!name)
1052                 return -ENOMEM;
1053
1054         res = name_to_dev_t(name);
1055         kfree(name);
1056         if (!res)
1057                 return -EINVAL;
1058
1059         lock_system_sleep();
1060         swsusp_resume_device = res;
1061         unlock_system_sleep();
1062         pm_pr_dbg("Configured resume from disk to %u\n", swsusp_resume_device);
1063         noresume = 0;
1064         software_resume();
1065         return n;
1066 }
1067
1068 power_attr(resume);
1069
1070 static ssize_t resume_offset_show(struct kobject *kobj,
1071                                   struct kobj_attribute *attr, char *buf)
1072 {
1073         return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1074 }
1075
1076 static ssize_t resume_offset_store(struct kobject *kobj,
1077                                    struct kobj_attribute *attr, const char *buf,
1078                                    size_t n)
1079 {
1080         unsigned long long offset;
1081         int rc;
1082
1083         rc = kstrtoull(buf, 0, &offset);
1084         if (rc)
1085                 return rc;
1086         swsusp_resume_block = offset;
1087
1088         return n;
1089 }
1090
1091 power_attr(resume_offset);
1092
1093 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1094                                char *buf)
1095 {
1096         return sprintf(buf, "%lu\n", image_size);
1097 }
1098
1099 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1100                                 const char *buf, size_t n)
1101 {
1102         unsigned long size;
1103
1104         if (sscanf(buf, "%lu", &size) == 1) {
1105                 image_size = size;
1106                 return n;
1107         }
1108
1109         return -EINVAL;
1110 }
1111
1112 power_attr(image_size);
1113
1114 static ssize_t reserved_size_show(struct kobject *kobj,
1115                                   struct kobj_attribute *attr, char *buf)
1116 {
1117         return sprintf(buf, "%lu\n", reserved_size);
1118 }
1119
1120 static ssize_t reserved_size_store(struct kobject *kobj,
1121                                    struct kobj_attribute *attr,
1122                                    const char *buf, size_t n)
1123 {
1124         unsigned long size;
1125
1126         if (sscanf(buf, "%lu", &size) == 1) {
1127                 reserved_size = size;
1128                 return n;
1129         }
1130
1131         return -EINVAL;
1132 }
1133
1134 power_attr(reserved_size);
1135
1136 static struct attribute * g[] = {
1137         &disk_attr.attr,
1138         &resume_offset_attr.attr,
1139         &resume_attr.attr,
1140         &image_size_attr.attr,
1141         &reserved_size_attr.attr,
1142         NULL,
1143 };
1144
1145
1146 static const struct attribute_group attr_group = {
1147         .attrs = g,
1148 };
1149
1150
1151 static int __init pm_disk_init(void)
1152 {
1153         return sysfs_create_group(power_kobj, &attr_group);
1154 }
1155
1156 core_initcall(pm_disk_init);
1157
1158
1159 static int __init resume_setup(char *str)
1160 {
1161         if (noresume)
1162                 return 1;
1163
1164         strncpy( resume_file, str, 255 );
1165         return 1;
1166 }
1167
1168 static int __init resume_offset_setup(char *str)
1169 {
1170         unsigned long long offset;
1171
1172         if (noresume)
1173                 return 1;
1174
1175         if (sscanf(str, "%llu", &offset) == 1)
1176                 swsusp_resume_block = offset;
1177
1178         return 1;
1179 }
1180
1181 static int __init hibernate_setup(char *str)
1182 {
1183         if (!strncmp(str, "noresume", 8)) {
1184                 noresume = 1;
1185         } else if (!strncmp(str, "nocompress", 10)) {
1186                 nocompress = 1;
1187         } else if (!strncmp(str, "no", 2)) {
1188                 noresume = 1;
1189                 nohibernate = 1;
1190         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1191                    && !strncmp(str, "protect_image", 13)) {
1192                 enable_restore_image_protection();
1193         }
1194         return 1;
1195 }
1196
1197 static int __init noresume_setup(char *str)
1198 {
1199         noresume = 1;
1200         return 1;
1201 }
1202
1203 static int __init resumewait_setup(char *str)
1204 {
1205         resume_wait = 1;
1206         return 1;
1207 }
1208
1209 static int __init resumedelay_setup(char *str)
1210 {
1211         int rc = kstrtouint(str, 0, &resume_delay);
1212
1213         if (rc)
1214                 return rc;
1215         return 1;
1216 }
1217
1218 static int __init nohibernate_setup(char *str)
1219 {
1220         noresume = 1;
1221         nohibernate = 1;
1222         return 1;
1223 }
1224
1225 __setup("noresume", noresume_setup);
1226 __setup("resume_offset=", resume_offset_setup);
1227 __setup("resume=", resume_setup);
1228 __setup("hibernate=", hibernate_setup);
1229 __setup("resumewait", resumewait_setup);
1230 __setup("resumedelay=", resumedelay_setup);
1231 __setup("nohibernate", nohibernate_setup);