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/syscalls.h>
  18 #include <linux/reboot.h>
  19 #include <linux/string.h>
  20 #include <linux/device.h>
  21 #include <linux/async.h>
  22 #include <linux/delay.h>
  23 #include <linux/fs.h>
  24 #include <linux/mount.h>
  25 #include <linux/pm.h>
  26 #include <linux/nmi.h>
  27 #include <linux/console.h>
  28 #include <linux/cpu.h>
  29 #include <linux/freezer.h>
  30 #include <linux/gfp.h>
  31 #include <linux/syscore_ops.h>
  32 #include <linux/ctype.h>
  33 #include <linux/genhd.h>
  34 #include <linux/ktime.h>
  35 #include <trace/events/power.h>
  36
  37 #include "power.h"
  38
  39
  40 static int nocompress;
  41 static int noresume;
  42 static int nohibernate;
  43 static int resume_wait;
  44 static unsigned int resume_delay;
  45 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  46 dev_t swsusp_resume_device;
  47 sector_t swsusp_resume_block;
  48 __visible int in_suspend __nosavedata;
  49
  50 enum {
  51         HIBERNATION_INVALID,
  52         HIBERNATION_PLATFORM,
  53         HIBERNATION_SHUTDOWN,
  54         HIBERNATION_REBOOT,
  55 #ifdef CONFIG_SUSPEND
  56         HIBERNATION_SUSPEND,
  57 #endif
  58         HIBERNATION_TEST_RESUME,
  59         /* keep last */
  60         __HIBERNATION_AFTER_LAST
  61 };
  62 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  63 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  64
  65 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  66
  67 bool freezer_test_done;
  68
  69 static const struct platform_hibernation_ops *hibernation_ops;
  70
  71 bool hibernation_available(void)
  72 {
  73         return (nohibernate == 0);
  74 }
  75
  76 /**
  77  * hibernation_set_ops - Set the global hibernate operations.
  78  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  79  */
  80 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  81 {
  82         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  83             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  84             && ops->restore_cleanup && ops->leave)) {
  85                 WARN_ON(1);
  86                 return;
  87         }
  88         lock_system_sleep();
  89         hibernation_ops = ops;
  90         if (ops)
  91                 hibernation_mode = HIBERNATION_PLATFORM;
  92         else if (hibernation_mode == HIBERNATION_PLATFORM)
  93                 hibernation_mode = HIBERNATION_SHUTDOWN;
  94
  95         unlock_system_sleep();
  96 }
  97 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  98
  99 static bool entering_platform_hibernation;
 100
 101 bool system_entering_hibernation(void)
 102 {
 103         return entering_platform_hibernation;
 104 }
 105 EXPORT_SYMBOL(system_entering_hibernation);
 106
 107 #ifdef CONFIG_PM_DEBUG
 108 static void hibernation_debug_sleep(void)
 109 {
 110         pr_info("hibernation debug: Waiting for 5 seconds.\n");
 111         mdelay(5000);
 112 }
 113
 114 static int hibernation_test(int level)
 115 {
 116         if (pm_test_level == level) {
 117                 hibernation_debug_sleep();
 118                 return 1;
 119         }
 120         return 0;
 121 }
 122 #else /* !CONFIG_PM_DEBUG */
 123 static int hibernation_test(int level) { return 0; }
 124 #endif /* !CONFIG_PM_DEBUG */
 125
 126 /**
 127  * platform_begin - Call platform to start hibernation.
 128  * @platform_mode: Whether or not to use the platform driver.
 129  */
 130 static int platform_begin(int platform_mode)
 131 {
 132         return (platform_mode && hibernation_ops) ?
 133                 hibernation_ops->begin() : 0;
 134 }
 135
 136 /**
 137  * platform_end - Call platform to finish transition to the working state.
 138  * @platform_mode: Whether or not to use the platform driver.
 139  */
 140 static void platform_end(int platform_mode)
 141 {
 142         if (platform_mode && hibernation_ops)
 143                 hibernation_ops->end();
 144 }
 145
 146 /**
 147  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 148  * @platform_mode: Whether or not to use the platform driver.
 149  *
 150  * Use the platform driver to prepare the system for creating a hibernate image,
 151  * if so configured, and return an error code if that fails.
 152  */
 153
 154 static int platform_pre_snapshot(int platform_mode)
 155 {
 156         return (platform_mode && hibernation_ops) ?
 157                 hibernation_ops->pre_snapshot() : 0;
 158 }
 159
 160 /**
 161  * platform_leave - Call platform to prepare a transition to the working state.
 162  * @platform_mode: Whether or not to use the platform driver.
 163  *
 164  * Use the platform driver prepare to prepare the machine for switching to the
 165  * normal mode of operation.
 166  *
 167  * This routine is called on one CPU with interrupts disabled.
 168  */
 169 static void platform_leave(int platform_mode)
 170 {
 171         if (platform_mode && hibernation_ops)
 172                 hibernation_ops->leave();
 173 }
 174
 175 /**
 176  * platform_finish - Call platform to switch the system to the working state.
 177  * @platform_mode: Whether or not to use the platform driver.
 178  *
 179  * Use the platform driver to switch the machine to the normal mode of
 180  * operation.
 181  *
 182  * This routine must be called after platform_prepare().
 183  */
 184 static void platform_finish(int platform_mode)
 185 {
 186         if (platform_mode && hibernation_ops)
 187                 hibernation_ops->finish();
 188 }
 189
 190 /**
 191  * platform_pre_restore - Prepare for hibernate image restoration.
 192  * @platform_mode: Whether or not to use the platform driver.
 193  *
 194  * Use the platform driver to prepare the system for resume from a hibernation
 195  * image.
 196  *
 197  * If the restore fails after this function has been called,
 198  * platform_restore_cleanup() must be called.
 199  */
 200 static int platform_pre_restore(int platform_mode)
 201 {
 202         return (platform_mode && hibernation_ops) ?
 203                 hibernation_ops->pre_restore() : 0;
 204 }
 205
 206 /**
 207  * platform_restore_cleanup - Switch to the working state after failing restore.
 208  * @platform_mode: Whether or not to use the platform driver.
 209  *
 210  * Use the platform driver to switch the system to the normal mode of operation
 211  * after a failing restore.
 212  *
 213  * If platform_pre_restore() has been called before the failing restore, this
 214  * function must be called too, regardless of the result of
 215  * platform_pre_restore().
 216  */
 217 static void platform_restore_cleanup(int platform_mode)
 218 {
 219         if (platform_mode && hibernation_ops)
 220                 hibernation_ops->restore_cleanup();
 221 }
 222
 223 /**
 224  * platform_recover - Recover from a failure to suspend devices.
 225  * @platform_mode: Whether or not to use the platform driver.
 226  */
 227 static void platform_recover(int platform_mode)
 228 {
 229         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 230                 hibernation_ops->recover();
 231 }
 232
 233 /**
 234  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 235  * @start: Starting event.
 236  * @stop: Final event.
 237  * @nr_pages: Number of memory pages processed between @start and @stop.
 238  * @msg: Additional diagnostic message to print.
 239  */
 240 void swsusp_show_speed(ktime_t start, ktime_t stop,
 241                       unsigned nr_pages, char *msg)
 242 {
 243         ktime_t diff;
 244         u64 elapsed_centisecs64;
 245         unsigned int centisecs;
 246         unsigned int k;
 247         unsigned int kps;
 248
 249         diff = ktime_sub(stop, start);
 250         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 251         centisecs = elapsed_centisecs64;
 252         if (centisecs == 0)
 253                 centisecs = 1;  /* avoid div-by-zero */
 254         k = nr_pages * (PAGE_SIZE / 1024);
 255         kps = (k * 100) / centisecs;
 256         pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 257                 msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 258                 (kps % 1000) / 10);
 259 }
 260
 261 __weak int arch_resume_nosmt(void)
 262 {
 263         return 0;
 264 }
 265
 266 /**
 267  * create_image - Create a hibernation image.
 268  * @platform_mode: Whether or not to use the platform driver.
 269  *
 270  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 271  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 272  *
 273  * Control reappears in this routine after the subsequent restore.
 274  */
 275 static int create_image(int platform_mode)
 276 {
 277         int error;
 278
 279         error = dpm_suspend_end(PMSG_FREEZE);
 280         if (error) {
 281                 pr_err("Some devices failed to power down, aborting hibernation\n");
 282                 return error;
 283         }
 284
 285         error = platform_pre_snapshot(platform_mode);
 286         if (error || hibernation_test(TEST_PLATFORM))
 287                 goto Platform_finish;
 288
 289         error = disable_nonboot_cpus();
 290         if (error || hibernation_test(TEST_CPUS))
 291                 goto Enable_cpus;
 292
 293         local_irq_disable();
 294
 295         error = syscore_suspend();
 296         if (error) {
 297                 pr_err("Some system devices failed to power down, aborting hibernation\n");
 298                 goto Enable_irqs;
 299         }
 300
 301         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 302                 goto Power_up;
 303
 304         in_suspend = 1;
 305         save_processor_state();
 306         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 307         error = swsusp_arch_suspend();
 308         /* Restore control flow magically appears here */
 309         restore_processor_state();
 310         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 311         if (error)
 312                 pr_err("Error %d creating hibernation image\n", error);
 313
 314         if (!in_suspend) {
 315                 events_check_enabled = false;
 316                 clear_free_pages();
 317         }
 318
 319         platform_leave(platform_mode);
 320
 321  Power_up:
 322         syscore_resume();
 323
 324  Enable_irqs:
 325         local_irq_enable();
 326
 327  Enable_cpus:
 328         enable_nonboot_cpus();
 329
 330         /* Allow architectures to do nosmt-specific post-resume dances */
 331         if (!in_suspend)
 332                 error = arch_resume_nosmt();
 333
 334  Platform_finish:
 335         platform_finish(platform_mode);
 336
 337         dpm_resume_start(in_suspend ?
 338                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 339
 340         return error;
 341 }
 342
 343 /**
 344  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 345  * @platform_mode: If set, use platform driver to prepare for the transition.
 346  *
 347  * This routine must be called with pm_mutex held.
 348  */
 349 int hibernation_snapshot(int platform_mode)
 350 {
 351         pm_message_t msg;
 352         int error;
 353
 354         pm_suspend_clear_flags();
 355         error = platform_begin(platform_mode);
 356         if (error)
 357                 goto Close;
 358
 359         /* Preallocate image memory before shutting down devices. */
 360         error = hibernate_preallocate_memory();
 361         if (error)
 362                 goto Close;
 363
 364         error = freeze_kernel_threads();
 365         if (error)
 366                 goto Cleanup;
 367
 368         if (hibernation_test(TEST_FREEZER)) {
 369
 370                 /*
 371                  * Indicate to the caller that we are returning due to a
 372                  * successful freezer test.
 373                  */
 374                 freezer_test_done = true;
 375                 goto Thaw;
 376         }
 377
 378         error = dpm_prepare(PMSG_FREEZE);
 379         if (error) {
 380                 dpm_complete(PMSG_RECOVER);
 381                 goto Thaw;
 382         }
 383
 384         suspend_console();
 385         pm_restrict_gfp_mask();
 386
 387         error = dpm_suspend(PMSG_FREEZE);
 388
 389         if (error || hibernation_test(TEST_DEVICES))
 390                 platform_recover(platform_mode);
 391         else
 392                 error = create_image(platform_mode);
 393
 394         /*
 395          * In the case that we call create_image() above, the control
 396          * returns here (1) after the image has been created or the
 397          * image creation has failed and (2) after a successful restore.
 398          */
 399
 400         /* We may need to release the preallocated image pages here. */
 401         if (error || !in_suspend)
 402                 swsusp_free();
 403
 404         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 405         dpm_resume(msg);
 406
 407         if (error || !in_suspend)
 408                 pm_restore_gfp_mask();
 409
 410         resume_console();
 411         dpm_complete(msg);
 412
 413  Close:
 414         platform_end(platform_mode);
 415         return error;
 416
 417  Thaw:
 418         thaw_kernel_threads();
 419  Cleanup:
 420         swsusp_free();
 421         goto Close;
 422 }
 423
 424 int __weak hibernate_resume_nonboot_cpu_disable(void)
 425 {
 426         return disable_nonboot_cpus();
 427 }
 428
 429 /**
 430  * resume_target_kernel - Restore system state from a hibernation image.
 431  * @platform_mode: Whether or not to use the platform driver.
 432  *
 433  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 434  * contents of highmem that have not been restored yet from the image and run
 435  * the low-level code that will restore the remaining contents of memory and
 436  * switch to the just restored target kernel.
 437  */
 438 static int resume_target_kernel(bool platform_mode)
 439 {
 440         int error;
 441
 442         error = dpm_suspend_end(PMSG_QUIESCE);
 443         if (error) {
 444                 pr_err("Some devices failed to power down, aborting resume\n");
 445                 return error;
 446         }
 447
 448         error = platform_pre_restore(platform_mode);
 449         if (error)
 450                 goto Cleanup;
 451
 452         error = hibernate_resume_nonboot_cpu_disable();
 453         if (error)
 454                 goto Enable_cpus;
 455
 456         local_irq_disable();
 457
 458         error = syscore_suspend();
 459         if (error)
 460                 goto Enable_irqs;
 461
 462         save_processor_state();
 463         error = restore_highmem();
 464         if (!error) {
 465                 error = swsusp_arch_resume();
 466                 /*
 467                  * The code below is only ever reached in case of a failure.
 468                  * Otherwise, execution continues at the place where
 469                  * swsusp_arch_suspend() was called.
 470                  */
 471                 BUG_ON(!error);
 472                 /*
 473                  * This call to restore_highmem() reverts the changes made by
 474                  * the previous one.
 475                  */
 476                 restore_highmem();
 477         }
 478         /*
 479          * The only reason why swsusp_arch_resume() can fail is memory being
 480          * very tight, so we have to free it as soon as we can to avoid
 481          * subsequent failures.
 482          */
 483         swsusp_free();
 484         restore_processor_state();
 485         touch_softlockup_watchdog();
 486
 487         syscore_resume();
 488
 489  Enable_irqs:
 490         local_irq_enable();
 491
 492  Enable_cpus:
 493         enable_nonboot_cpus();
 494
 495  Cleanup:
 496         platform_restore_cleanup(platform_mode);
 497
 498         dpm_resume_start(PMSG_RECOVER);
 499
 500         return error;
 501 }
 502
 503 /**
 504  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 505  * @platform_mode: If set, use platform driver to prepare for the transition.
 506  *
 507  * This routine must be called with pm_mutex held.  If it is successful, control
 508  * reappears in the restored target kernel in hibernation_snapshot().
 509  */
 510 int hibernation_restore(int platform_mode)
 511 {
 512         int error;
 513
 514         pm_prepare_console();
 515         suspend_console();
 516         pm_restrict_gfp_mask();
 517         error = dpm_suspend_start(PMSG_QUIESCE);
 518         if (!error) {
 519                 error = resume_target_kernel(platform_mode);
 520                 /*
 521                  * The above should either succeed and jump to the new kernel,
 522                  * or return with an error. Otherwise things are just
 523                  * undefined, so let's be paranoid.
 524                  */
 525                 BUG_ON(!error);
 526         }
 527         dpm_resume_end(PMSG_RECOVER);
 528         pm_restore_gfp_mask();
 529         resume_console();
 530         pm_restore_console();
 531         return error;
 532 }
 533
 534 /**
 535  * hibernation_platform_enter - Power off the system using the platform driver.
 536  */
 537 int hibernation_platform_enter(void)
 538 {
 539         int error;
 540
 541         if (!hibernation_ops)
 542                 return -ENOSYS;
 543
 544         /*
 545          * We have cancelled the power transition by running
 546          * hibernation_ops->finish() before saving the image, so we should let
 547          * the firmware know that we're going to enter the sleep state after all
 548          */
 549         error = hibernation_ops->begin();
 550         if (error)
 551                 goto Close;
 552
 553         entering_platform_hibernation = true;
 554         suspend_console();
 555         error = dpm_suspend_start(PMSG_HIBERNATE);
 556         if (error) {
 557                 if (hibernation_ops->recover)
 558                         hibernation_ops->recover();
 559                 goto Resume_devices;
 560         }
 561
 562         error = dpm_suspend_end(PMSG_HIBERNATE);
 563         if (error)
 564                 goto Resume_devices;
 565
 566         error = hibernation_ops->prepare();
 567         if (error)
 568                 goto Platform_finish;
 569
 570         error = disable_nonboot_cpus();
 571         if (error)
 572                 goto Enable_cpus;
 573
 574         local_irq_disable();
 575         syscore_suspend();
 576         if (pm_wakeup_pending()) {
 577                 error = -EAGAIN;
 578                 goto Power_up;
 579         }
 580
 581         hibernation_ops->enter();
 582         /* We should never get here */
 583         while (1);
 584
 585  Power_up:
 586         syscore_resume();
 587         local_irq_enable();
 588
 589  Enable_cpus:
 590         enable_nonboot_cpus();
 591
 592  Platform_finish:
 593         hibernation_ops->finish();
 594
 595         dpm_resume_start(PMSG_RESTORE);
 596
 597  Resume_devices:
 598         entering_platform_hibernation = false;
 599         dpm_resume_end(PMSG_RESTORE);
 600         resume_console();
 601
 602  Close:
 603         hibernation_ops->end();
 604
 605         return error;
 606 }
 607
 608 /**
 609  * power_down - Shut the machine down for hibernation.
 610  *
 611  * Use the platform driver, if configured, to put the system into the sleep
 612  * state corresponding to hibernation, or try to power it off or reboot,
 613  * depending on the value of hibernation_mode.
 614  */
 615 static void power_down(void)
 616 {
 617 #ifdef CONFIG_SUSPEND
 618         int error;
 619
 620         if (hibernation_mode == HIBERNATION_SUSPEND) {
 621                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 622                 if (error) {
 623                         hibernation_mode = hibernation_ops ?
 624                                                 HIBERNATION_PLATFORM :
 625                                                 HIBERNATION_SHUTDOWN;
 626                 } else {
 627                         /* Restore swap signature. */
 628                         error = swsusp_unmark();
 629                         if (error)
 630                                 pr_err("Swap will be unusable! Try swapon -a.\n");
 631
 632                         return;
 633                 }
 634         }
 635 #endif
 636
 637         switch (hibernation_mode) {
 638         case HIBERNATION_REBOOT:
 639                 kernel_restart(NULL);
 640                 break;
 641         case HIBERNATION_PLATFORM:
 642                 hibernation_platform_enter();
 643         case HIBERNATION_SHUTDOWN:
 644                 if (pm_power_off)
 645                         kernel_power_off();
 646                 break;
 647         }
 648         kernel_halt();
 649         /*
 650          * Valid image is on the disk, if we continue we risk serious data
 651          * corruption after resume.
 652          */
 653         pr_crit("Power down manually\n");
 654         while (1)
 655                 cpu_relax();
 656 }
 657
 658 static int load_image_and_restore(void)
 659 {
 660         int error;
 661         unsigned int flags;
 662
 663         pm_pr_dbg("Loading hibernation image.\n");
 664
 665         lock_device_hotplug();
 666         error = create_basic_memory_bitmaps();
 667         if (error)
 668                 goto Unlock;
 669
 670         error = swsusp_read(&flags);
 671         swsusp_close(FMODE_READ | FMODE_EXCL);
 672         if (!error)
 673                 hibernation_restore(flags & SF_PLATFORM_MODE);
 674
 675         pr_err("Failed to load hibernation image, recovering.\n");
 676         swsusp_free();
 677         free_basic_memory_bitmaps();
 678  Unlock:
 679         unlock_device_hotplug();
 680
 681         return error;
 682 }
 683
 684 /**
 685  * hibernate - Carry out system hibernation, including saving the image.
 686  */
 687 int hibernate(void)
 688 {
 689         int error, nr_calls = 0;
 690         bool snapshot_test = false;
 691
 692         if (!hibernation_available()) {
 693                 pm_pr_dbg("Hibernation not available.\n");
 694                 return -EPERM;
 695         }
 696
 697         lock_system_sleep();
 698         /* The snapshot device should not be opened while we're running */
 699         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 700                 error = -EBUSY;
 701                 goto Unlock;
 702         }
 703
 704         pr_info("hibernation entry\n");
 705         pm_prepare_console();
 706         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 707         if (error) {
 708                 nr_calls--;
 709                 goto Exit;
 710         }
 711
 712         pr_info("Syncing filesystems ... \n");
 713         sys_sync();
 714         pr_info("done.\n");
 715
 716         error = freeze_processes();
 717         if (error)
 718                 goto Exit;
 719
 720         lock_device_hotplug();
 721         /* Allocate memory management structures */
 722         error = create_basic_memory_bitmaps();
 723         if (error)
 724                 goto Thaw;
 725
 726         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 727         if (error || freezer_test_done)
 728                 goto Free_bitmaps;
 729
 730         if (in_suspend) {
 731                 unsigned int flags = 0;
 732
 733                 if (hibernation_mode == HIBERNATION_PLATFORM)
 734                         flags |= SF_PLATFORM_MODE;
 735                 if (nocompress)
 736                         flags |= SF_NOCOMPRESS_MODE;
 737                 else
 738                         flags |= SF_CRC32_MODE;
 739
 740                 pm_pr_dbg("Writing image.\n");
 741                 error = swsusp_write(flags);
 742                 swsusp_free();
 743                 if (!error) {
 744                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 745                                 snapshot_test = true;
 746                         else
 747                                 power_down();
 748                 }
 749                 in_suspend = 0;
 750                 pm_restore_gfp_mask();
 751         } else {
 752                 pm_pr_dbg("Image restored successfully.\n");
 753         }
 754
 755  Free_bitmaps:
 756         free_basic_memory_bitmaps();
 757  Thaw:
 758         unlock_device_hotplug();
 759         if (snapshot_test) {
 760                 pm_pr_dbg("Checking hibernation image\n");
 761                 error = swsusp_check();
 762                 if (!error)
 763                         error = load_image_and_restore();
 764         }
 765         thaw_processes();
 766
 767         /* Don't bother checking whether freezer_test_done is true */
 768         freezer_test_done = false;
 769  Exit:
 770         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 771         pm_restore_console();
 772         atomic_inc(&snapshot_device_available);
 773  Unlock:
 774         unlock_system_sleep();
 775         pr_info("hibernation exit\n");
 776
 777         return error;
 778 }
 779
 780
 781 /**
 782  * software_resume - Resume from a saved hibernation image.
 783  *
 784  * This routine is called as a late initcall, when all devices have been
 785  * discovered and initialized already.
 786  *
 787  * The image reading code is called to see if there is a hibernation image
 788  * available for reading.  If that is the case, devices are quiesced and the
 789  * contents of memory is restored from the saved image.
 790  *
 791  * If this is successful, control reappears in the restored target kernel in
 792  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 793  * attempts to recover gracefully and make the kernel return to the normal mode
 794  * of operation.
 795  */
 796 static int software_resume(void)
 797 {
 798         int error, nr_calls = 0;
 799
 800         /*
 801          * If the user said "noresume".. bail out early.
 802          */
 803         if (noresume || !hibernation_available())
 804                 return 0;
 805
 806         /*
 807          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 808          * is configured into the kernel. Since the regular hibernate
 809          * trigger path is via sysfs which takes a buffer mutex before
 810          * calling hibernate functions (which take pm_mutex) this can
 811          * cause lockdep to complain about a possible ABBA deadlock
 812          * which cannot happen since we're in the boot code here and
 813          * sysfs can't be invoked yet. Therefore, we use a subclass
 814          * here to avoid lockdep complaining.
 815          */
 816         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 817
 818         if (swsusp_resume_device)
 819                 goto Check_image;
 820
 821         if (!strlen(resume_file)) {
 822                 error = -ENOENT;
 823                 goto Unlock;
 824         }
 825
 826         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 827
 828         if (resume_delay) {
 829                 pr_info("Waiting %dsec before reading resume device ...\n",
 830                         resume_delay);
 831                 ssleep(resume_delay);
 832         }
 833
 834         /* Check if the device is there */
 835         swsusp_resume_device = name_to_dev_t(resume_file);
 836         if (!swsusp_resume_device) {
 837                 /*
 838                  * Some device discovery might still be in progress; we need
 839                  * to wait for this to finish.
 840                  */
 841                 wait_for_device_probe();
 842
 843                 if (resume_wait) {
 844                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 845                                 msleep(10);
 846                         async_synchronize_full();
 847                 }
 848
 849                 swsusp_resume_device = name_to_dev_t(resume_file);
 850                 if (!swsusp_resume_device) {
 851                         error = -ENODEV;
 852                         goto Unlock;
 853                 }
 854         }
 855
 856  Check_image:
 857         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 858                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 859
 860         pm_pr_dbg("Looking for hibernation image.\n");
 861         error = swsusp_check();
 862         if (error)
 863                 goto Unlock;
 864
 865         /* The snapshot device should not be opened while we're running */
 866         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 867                 error = -EBUSY;
 868                 swsusp_close(FMODE_READ | FMODE_EXCL);
 869                 goto Unlock;
 870         }
 871
 872         pr_info("resume from hibernation\n");
 873         pm_prepare_console();
 874         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 875         if (error) {
 876                 nr_calls--;
 877                 goto Close_Finish;
 878         }
 879
 880         pm_pr_dbg("Preparing processes for restore.\n");
 881         error = freeze_processes();
 882         if (error)
 883                 goto Close_Finish;
 884
 885         error = freeze_kernel_threads();
 886         if (error) {
 887                 thaw_processes();
 888                 goto Close_Finish;
 889         }
 890
 891         error = load_image_and_restore();
 892         thaw_processes();
 893  Finish:
 894         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 895         pm_restore_console();
 896         pr_info("resume from hibernation failed (%d)\n", error);
 897         atomic_inc(&snapshot_device_available);
 898         /* For success case, the suspend path will release the lock */
 899  Unlock:
 900         mutex_unlock(&pm_mutex);
 901         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 902         return error;
 903  Close_Finish:
 904         swsusp_close(FMODE_READ | FMODE_EXCL);
 905         goto Finish;
 906 }
 907
 908 late_initcall_sync(software_resume);
 909
 910
 911 static const char * const hibernation_modes[] = {
 912         [HIBERNATION_PLATFORM]  = "platform",
 913         [HIBERNATION_SHUTDOWN]  = "shutdown",
 914         [HIBERNATION_REBOOT]    = "reboot",
 915 #ifdef CONFIG_SUSPEND
 916         [HIBERNATION_SUSPEND]   = "suspend",
 917 #endif
 918         [HIBERNATION_TEST_RESUME]       = "test_resume",
 919 };
 920
 921 /*
 922  * /sys/power/disk - Control hibernation mode.
 923  *
 924  * Hibernation can be handled in several ways.  There are a few different ways
 925  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 926  * or other hibernation_ops), powering it off or rebooting it (for testing
 927  * mostly).
 928  *
 929  * The sysfs file /sys/power/disk provides an interface for selecting the
 930  * hibernation mode to use.  Reading from this file causes the available modes
 931  * to be printed.  There are 3 modes that can be supported:
 932  *
 933  *      'platform'
 934  *      'shutdown'
 935  *      'reboot'
 936  *
 937  * If a platform hibernation driver is in use, 'platform' will be supported
 938  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 939  * The selected option (i.e. the one corresponding to the current value of
 940  * hibernation_mode) is enclosed by a square bracket.
 941  *
 942  * To select a given hibernation mode it is necessary to write the mode's
 943  * string representation (as returned by reading from /sys/power/disk) back
 944  * into /sys/power/disk.
 945  */
 946
 947 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 948                          char *buf)
 949 {
 950         int i;
 951         char *start = buf;
 952
 953         if (!hibernation_available())
 954                 return sprintf(buf, "[disabled]\n");
 955
 956         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 957                 if (!hibernation_modes[i])
 958                         continue;
 959                 switch (i) {
 960                 case HIBERNATION_SHUTDOWN:
 961                 case HIBERNATION_REBOOT:
 962 #ifdef CONFIG_SUSPEND
 963                 case HIBERNATION_SUSPEND:
 964 #endif
 965                 case HIBERNATION_TEST_RESUME:
 966                         break;
 967                 case HIBERNATION_PLATFORM:
 968                         if (hibernation_ops)
 969                                 break;
 970                         /* not a valid mode, continue with loop */
 971                         continue;
 972                 }
 973                 if (i == hibernation_mode)
 974                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 975                 else
 976                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 977         }
 978         buf += sprintf(buf, "\n");
 979         return buf-start;
 980 }
 981
 982 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 983                           const char *buf, size_t n)
 984 {
 985         int error = 0;
 986         int i;
 987         int len;
 988         char *p;
 989         int mode = HIBERNATION_INVALID;
 990
 991         if (!hibernation_available())
 992                 return -EPERM;
 993
 994         p = memchr(buf, '\n', n);
 995         len = p ? p - buf : n;
 996
 997         lock_system_sleep();
 998         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 999                 if (len == strlen(hibernation_modes[i])
1000                     && !strncmp(buf, hibernation_modes[i], len)) {
1001                         mode = i;
1002                         break;
1003                 }
1004         }
1005         if (mode != HIBERNATION_INVALID) {
1006                 switch (mode) {
1007                 case HIBERNATION_SHUTDOWN:
1008                 case HIBERNATION_REBOOT:
1009 #ifdef CONFIG_SUSPEND
1010                 case HIBERNATION_SUSPEND:
1011 #endif
1012                 case HIBERNATION_TEST_RESUME:
1013                         hibernation_mode = mode;
1014                         break;
1015                 case HIBERNATION_PLATFORM:
1016                         if (hibernation_ops)
1017                                 hibernation_mode = mode;
1018                         else
1019                                 error = -EINVAL;
1020                 }
1021         } else
1022                 error = -EINVAL;
1023
1024         if (!error)
1025                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1026                                hibernation_modes[mode]);
1027         unlock_system_sleep();
1028         return error ? error : n;
1029 }
1030
1031 power_attr(disk);
1032
1033 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1034                            char *buf)
1035 {
1036         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1037                        MINOR(swsusp_resume_device));
1038 }
1039
1040 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1041                             const char *buf, size_t n)
1042 {
1043         dev_t res;
1044         int len = n;
1045         char *name;
1046
1047         if (len && buf[len-1] == '\n')
1048                 len--;
1049         name = kstrndup(buf, len, GFP_KERNEL);
1050         if (!name)
1051                 return -ENOMEM;
1052
1053         res = name_to_dev_t(name);
1054         kfree(name);
1055         if (!res)
1056                 return -EINVAL;
1057
1058         lock_system_sleep();
1059         swsusp_resume_device = res;
1060         unlock_system_sleep();
1061         pr_info("Starting manual resume from disk\n");
1062         noresume = 0;
1063         software_resume();
1064         return n;
1065 }
1066
1067 power_attr(resume);
1068
1069 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1070                                char *buf)
1071 {
1072         return sprintf(buf, "%lu\n", image_size);
1073 }
1074
1075 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1076                                 const char *buf, size_t n)
1077 {
1078         unsigned long size;
1079
1080         if (sscanf(buf, "%lu", &size) == 1) {
1081                 image_size = size;
1082                 return n;
1083         }
1084
1085         return -EINVAL;
1086 }
1087
1088 power_attr(image_size);
1089
1090 static ssize_t reserved_size_show(struct kobject *kobj,
1091                                   struct kobj_attribute *attr, char *buf)
1092 {
1093         return sprintf(buf, "%lu\n", reserved_size);
1094 }
1095
1096 static ssize_t reserved_size_store(struct kobject *kobj,
1097                                    struct kobj_attribute *attr,
1098                                    const char *buf, size_t n)
1099 {
1100         unsigned long size;
1101
1102         if (sscanf(buf, "%lu", &size) == 1) {
1103                 reserved_size = size;
1104                 return n;
1105         }
1106
1107         return -EINVAL;
1108 }
1109
1110 power_attr(reserved_size);
1111
1112 static struct attribute * g[] = {
1113         &disk_attr.attr,
1114         &resume_attr.attr,
1115         &image_size_attr.attr,
1116         &reserved_size_attr.attr,
1117         NULL,
1118 };
1119
1120
1121 static const struct attribute_group attr_group = {
1122         .attrs = g,
1123 };
1124
1125
1126 static int __init pm_disk_init(void)
1127 {
1128         return sysfs_create_group(power_kobj, &attr_group);
1129 }
1130
1131 core_initcall(pm_disk_init);
1132
1133
1134 static int __init resume_setup(char *str)
1135 {
1136         if (noresume)
1137                 return 1;
1138
1139         strncpy( resume_file, str, 255 );
1140         return 1;
1141 }
1142
1143 static int __init resume_offset_setup(char *str)
1144 {
1145         unsigned long long offset;
1146
1147         if (noresume)
1148                 return 1;
1149
1150         if (sscanf(str, "%llu", &offset) == 1)
1151                 swsusp_resume_block = offset;
1152
1153         return 1;
1154 }
1155
1156 static int __init hibernate_setup(char *str)
1157 {
1158         if (!strncmp(str, "noresume", 8)) {
1159                 noresume = 1;
1160         } else if (!strncmp(str, "nocompress", 10)) {
1161                 nocompress = 1;
1162         } else if (!strncmp(str, "no", 2)) {
1163                 noresume = 1;
1164                 nohibernate = 1;
1165         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1166                    && !strncmp(str, "protect_image", 13)) {
1167                 enable_restore_image_protection();
1168         }
1169         return 1;
1170 }
1171
1172 static int __init noresume_setup(char *str)
1173 {
1174         noresume = 1;
1175         return 1;
1176 }
1177
1178 static int __init resumewait_setup(char *str)
1179 {
1180         resume_wait = 1;
1181         return 1;
1182 }
1183
1184 static int __init resumedelay_setup(char *str)
1185 {
1186         int rc = kstrtouint(str, 0, &resume_delay);
1187
1188         if (rc)
1189                 return rc;
1190         return 1;
1191 }
1192
1193 static int __init nohibernate_setup(char *str)
1194 {
1195         noresume = 1;
1196         nohibernate = 1;
1197         return 1;
1198 }
1199
1200 __setup("noresume", noresume_setup);
1201 __setup("resume_offset=", resume_offset_setup);
1202 __setup("resume=", resume_setup);
1203 __setup("hibernate=", hibernate_setup);
1204 __setup("resumewait", resumewait_setup);
1205 __setup("resumedelay=", resumedelay_setup);
1206 __setup("nohibernate", nohibernate_setup);