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 /**
 262  * create_image - Create a hibernation image.
 263  * @platform_mode: Whether or not to use the platform driver.
 264  *
 265  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 266  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 267  *
 268  * Control reappears in this routine after the subsequent restore.
 269  */
 270 static int create_image(int platform_mode)
 271 {
 272         int error;
 273
 274         error = dpm_suspend_end(PMSG_FREEZE);
 275         if (error) {
 276                 pr_err("Some devices failed to power down, aborting hibernation\n");
 277                 return error;
 278         }
 279
 280         error = platform_pre_snapshot(platform_mode);
 281         if (error || hibernation_test(TEST_PLATFORM))
 282                 goto Platform_finish;
 283
 284         error = disable_nonboot_cpus();
 285         if (error || hibernation_test(TEST_CPUS))
 286                 goto Enable_cpus;
 287
 288         local_irq_disable();
 289
 290         system_state = SYSTEM_SUSPEND;
 291
 292         error = syscore_suspend();
 293         if (error) {
 294                 pr_err("Some system devices failed to power down, aborting hibernation\n");
 295                 goto Enable_irqs;
 296         }
 297
 298         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 299                 goto Power_up;
 300
 301         in_suspend = 1;
 302         save_processor_state();
 303         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 304         error = swsusp_arch_suspend();
 305         /* Restore control flow magically appears here */
 306         restore_processor_state();
 307         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 308         if (error)
 309                 pr_err("Error %d creating hibernation image\n", error);
 310
 311         if (!in_suspend) {
 312                 events_check_enabled = false;
 313                 clear_free_pages();
 314         }
 315
 316         platform_leave(platform_mode);
 317
 318  Power_up:
 319         syscore_resume();
 320
 321  Enable_irqs:
 322         system_state = SYSTEM_RUNNING;
 323         local_irq_enable();
 324
 325  Enable_cpus:
 326         enable_nonboot_cpus();
 327
 328  Platform_finish:
 329         platform_finish(platform_mode);
 330
 331         dpm_resume_start(in_suspend ?
 332                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 333
 334         return error;
 335 }
 336
 337 /**
 338  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 339  * @platform_mode: If set, use platform driver to prepare for the transition.
 340  *
 341  * This routine must be called with pm_mutex held.
 342  */
 343 int hibernation_snapshot(int platform_mode)
 344 {
 345         pm_message_t msg;
 346         int error;
 347
 348         pm_suspend_clear_flags();
 349         error = platform_begin(platform_mode);
 350         if (error)
 351                 goto Close;
 352
 353         /* Preallocate image memory before shutting down devices. */
 354         error = hibernate_preallocate_memory();
 355         if (error)
 356                 goto Close;
 357
 358         error = freeze_kernel_threads();
 359         if (error)
 360                 goto Cleanup;
 361
 362         if (hibernation_test(TEST_FREEZER)) {
 363
 364                 /*
 365                  * Indicate to the caller that we are returning due to a
 366                  * successful freezer test.
 367                  */
 368                 freezer_test_done = true;
 369                 goto Thaw;
 370         }
 371
 372         error = dpm_prepare(PMSG_FREEZE);
 373         if (error) {
 374                 dpm_complete(PMSG_RECOVER);
 375                 goto Thaw;
 376         }
 377
 378         suspend_console();
 379         pm_restrict_gfp_mask();
 380
 381         error = dpm_suspend(PMSG_FREEZE);
 382
 383         if (error || hibernation_test(TEST_DEVICES))
 384                 platform_recover(platform_mode);
 385         else
 386                 error = create_image(platform_mode);
 387
 388         /*
 389          * In the case that we call create_image() above, the control
 390          * returns here (1) after the image has been created or the
 391          * image creation has failed and (2) after a successful restore.
 392          */
 393
 394         /* We may need to release the preallocated image pages here. */
 395         if (error || !in_suspend)
 396                 swsusp_free();
 397
 398         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 399         dpm_resume(msg);
 400
 401         if (error || !in_suspend)
 402                 pm_restore_gfp_mask();
 403
 404         resume_console();
 405         dpm_complete(msg);
 406
 407  Close:
 408         platform_end(platform_mode);
 409         return error;
 410
 411  Thaw:
 412         thaw_kernel_threads();
 413  Cleanup:
 414         swsusp_free();
 415         goto Close;
 416 }
 417
 418 int __weak hibernate_resume_nonboot_cpu_disable(void)
 419 {
 420         return disable_nonboot_cpus();
 421 }
 422
 423 /**
 424  * resume_target_kernel - Restore system state from a hibernation image.
 425  * @platform_mode: Whether or not to use the platform driver.
 426  *
 427  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 428  * contents of highmem that have not been restored yet from the image and run
 429  * the low-level code that will restore the remaining contents of memory and
 430  * switch to the just restored target kernel.
 431  */
 432 static int resume_target_kernel(bool platform_mode)
 433 {
 434         int error;
 435
 436         error = dpm_suspend_end(PMSG_QUIESCE);
 437         if (error) {
 438                 pr_err("Some devices failed to power down, aborting resume\n");
 439                 return error;
 440         }
 441
 442         error = platform_pre_restore(platform_mode);
 443         if (error)
 444                 goto Cleanup;
 445
 446         error = hibernate_resume_nonboot_cpu_disable();
 447         if (error)
 448                 goto Enable_cpus;
 449
 450         local_irq_disable();
 451         system_state = SYSTEM_SUSPEND;
 452
 453         error = syscore_suspend();
 454         if (error)
 455                 goto Enable_irqs;
 456
 457         save_processor_state();
 458         error = restore_highmem();
 459         if (!error) {
 460                 error = swsusp_arch_resume();
 461                 /*
 462                  * The code below is only ever reached in case of a failure.
 463                  * Otherwise, execution continues at the place where
 464                  * swsusp_arch_suspend() was called.
 465                  */
 466                 BUG_ON(!error);
 467                 /*
 468                  * This call to restore_highmem() reverts the changes made by
 469                  * the previous one.
 470                  */
 471                 restore_highmem();
 472         }
 473         /*
 474          * The only reason why swsusp_arch_resume() can fail is memory being
 475          * very tight, so we have to free it as soon as we can to avoid
 476          * subsequent failures.
 477          */
 478         swsusp_free();
 479         restore_processor_state();
 480         touch_softlockup_watchdog();
 481
 482         syscore_resume();
 483
 484  Enable_irqs:
 485         system_state = SYSTEM_RUNNING;
 486         local_irq_enable();
 487
 488  Enable_cpus:
 489         enable_nonboot_cpus();
 490
 491  Cleanup:
 492         platform_restore_cleanup(platform_mode);
 493
 494         dpm_resume_start(PMSG_RECOVER);
 495
 496         return error;
 497 }
 498
 499 /**
 500  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 501  * @platform_mode: If set, use platform driver to prepare for the transition.
 502  *
 503  * This routine must be called with pm_mutex held.  If it is successful, control
 504  * reappears in the restored target kernel in 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 = disable_nonboot_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         enable_nonboot_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         case HIBERNATION_SHUTDOWN:
 642                 if (pm_power_off)
 643                         kernel_power_off();
 644                 break;
 645         }
 646         kernel_halt();
 647         /*
 648          * Valid image is on the disk, if we continue we risk serious data
 649          * corruption after resume.
 650          */
 651         pr_crit("Power down manually\n");
 652         while (1)
 653                 cpu_relax();
 654 }
 655
 656 static int load_image_and_restore(void)
 657 {
 658         int error;
 659         unsigned int flags;
 660
 661         pm_pr_dbg("Loading hibernation image.\n");
 662
 663         lock_device_hotplug();
 664         error = create_basic_memory_bitmaps();
 665         if (error)
 666                 goto Unlock;
 667
 668         error = swsusp_read(&flags);
 669         swsusp_close(FMODE_READ);
 670         if (!error)
 671                 hibernation_restore(flags & SF_PLATFORM_MODE);
 672
 673         pr_err("Failed to load hibernation image, recovering.\n");
 674         swsusp_free();
 675         free_basic_memory_bitmaps();
 676  Unlock:
 677         unlock_device_hotplug();
 678
 679         return error;
 680 }
 681
 682 /**
 683  * hibernate - Carry out system hibernation, including saving the image.
 684  */
 685 int hibernate(void)
 686 {
 687         int error, nr_calls = 0;
 688         bool snapshot_test = false;
 689
 690         if (!hibernation_available()) {
 691                 pm_pr_dbg("Hibernation not available.\n");
 692                 return -EPERM;
 693         }
 694
 695         lock_system_sleep();
 696         /* The snapshot device should not be opened while we're running */
 697         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 698                 error = -EBUSY;
 699                 goto Unlock;
 700         }
 701
 702         pr_info("hibernation entry\n");
 703         pm_prepare_console();
 704         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 705         if (error) {
 706                 nr_calls--;
 707                 goto Exit;
 708         }
 709
 710         pr_info("Syncing filesystems ... \n");
 711         ksys_sync();
 712         pr_info("done.\n");
 713
 714         error = freeze_processes();
 715         if (error)
 716                 goto Exit;
 717
 718         lock_device_hotplug();
 719         /* Allocate memory management structures */
 720         error = create_basic_memory_bitmaps();
 721         if (error)
 722                 goto Thaw;
 723
 724         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 725         if (error || freezer_test_done)
 726                 goto Free_bitmaps;
 727
 728         if (in_suspend) {
 729                 unsigned int flags = 0;
 730
 731                 if (hibernation_mode == HIBERNATION_PLATFORM)
 732                         flags |= SF_PLATFORM_MODE;
 733                 if (nocompress)
 734                         flags |= SF_NOCOMPRESS_MODE;
 735                 else
 736                         flags |= SF_CRC32_MODE;
 737
 738                 pm_pr_dbg("Writing image.\n");
 739                 error = swsusp_write(flags);
 740                 swsusp_free();
 741                 if (!error) {
 742                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 743                                 snapshot_test = true;
 744                         else
 745                                 power_down();
 746                 }
 747                 in_suspend = 0;
 748                 pm_restore_gfp_mask();
 749         } else {
 750                 pm_pr_dbg("Image restored successfully.\n");
 751         }
 752
 753  Free_bitmaps:
 754         free_basic_memory_bitmaps();
 755  Thaw:
 756         unlock_device_hotplug();
 757         if (snapshot_test) {
 758                 pm_pr_dbg("Checking hibernation image\n");
 759                 error = swsusp_check();
 760                 if (!error)
 761                         error = load_image_and_restore();
 762         }
 763         thaw_processes();
 764
 765         /* Don't bother checking whether freezer_test_done is true */
 766         freezer_test_done = false;
 767  Exit:
 768         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 769         pm_restore_console();
 770         atomic_inc(&snapshot_device_available);
 771  Unlock:
 772         unlock_system_sleep();
 773         pr_info("hibernation exit\n");
 774
 775         return error;
 776 }
 777
 778
 779 /**
 780  * software_resume - Resume from a saved hibernation image.
 781  *
 782  * This routine is called as a late initcall, when all devices have been
 783  * discovered and initialized already.
 784  *
 785  * The image reading code is called to see if there is a hibernation image
 786  * available for reading.  If that is the case, devices are quiesced and the
 787  * contents of memory is restored from the saved image.
 788  *
 789  * If this is successful, control reappears in the restored target kernel in
 790  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 791  * attempts to recover gracefully and make the kernel return to the normal mode
 792  * of operation.
 793  */
 794 static int software_resume(void)
 795 {
 796         int error, nr_calls = 0;
 797
 798         /*
 799          * If the user said "noresume".. bail out early.
 800          */
 801         if (noresume || !hibernation_available())
 802                 return 0;
 803
 804         /*
 805          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 806          * is configured into the kernel. Since the regular hibernate
 807          * trigger path is via sysfs which takes a buffer mutex before
 808          * calling hibernate functions (which take pm_mutex) this can
 809          * cause lockdep to complain about a possible ABBA deadlock
 810          * which cannot happen since we're in the boot code here and
 811          * sysfs can't be invoked yet. Therefore, we use a subclass
 812          * here to avoid lockdep complaining.
 813          */
 814         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 815
 816         if (swsusp_resume_device)
 817                 goto Check_image;
 818
 819         if (!strlen(resume_file)) {
 820                 error = -ENOENT;
 821                 goto Unlock;
 822         }
 823
 824         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 825
 826         if (resume_delay) {
 827                 pr_info("Waiting %dsec before reading resume device ...\n",
 828                         resume_delay);
 829                 ssleep(resume_delay);
 830         }
 831
 832         /* Check if the device is there */
 833         swsusp_resume_device = name_to_dev_t(resume_file);
 834
 835         /*
 836          * name_to_dev_t is ineffective to verify parition if resume_file is in
 837          * integer format. (e.g. major:minor)
 838          */
 839         if (isdigit(resume_file[0]) && resume_wait) {
 840                 int partno;
 841                 while (!get_gendisk(swsusp_resume_device, &partno))
 842                         msleep(10);
 843         }
 844
 845         if (!swsusp_resume_device) {
 846                 /*
 847                  * Some device discovery might still be in progress; we need
 848                  * to wait for this to finish.
 849                  */
 850                 wait_for_device_probe();
 851
 852                 if (resume_wait) {
 853                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 854                                 msleep(10);
 855                         async_synchronize_full();
 856                 }
 857
 858                 swsusp_resume_device = name_to_dev_t(resume_file);
 859                 if (!swsusp_resume_device) {
 860                         error = -ENODEV;
 861                         goto Unlock;
 862                 }
 863         }
 864
 865  Check_image:
 866         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 867                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 868
 869         pm_pr_dbg("Looking for hibernation image.\n");
 870         error = swsusp_check();
 871         if (error)
 872                 goto Unlock;
 873
 874         /* The snapshot device should not be opened while we're running */
 875         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 876                 error = -EBUSY;
 877                 swsusp_close(FMODE_READ);
 878                 goto Unlock;
 879         }
 880
 881         pr_info("resume from hibernation\n");
 882         pm_prepare_console();
 883         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 884         if (error) {
 885                 nr_calls--;
 886                 goto Close_Finish;
 887         }
 888
 889         pm_pr_dbg("Preparing processes for restore.\n");
 890         error = freeze_processes();
 891         if (error)
 892                 goto Close_Finish;
 893         error = load_image_and_restore();
 894         thaw_processes();
 895  Finish:
 896         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 897         pm_restore_console();
 898         pr_info("resume from hibernation failed (%d)\n", error);
 899         atomic_inc(&snapshot_device_available);
 900         /* For success case, the suspend path will release the lock */
 901  Unlock:
 902         mutex_unlock(&pm_mutex);
 903         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 904         return error;
 905  Close_Finish:
 906         swsusp_close(FMODE_READ);
 907         goto Finish;
 908 }
 909
 910 late_initcall_sync(software_resume);
 911
 912
 913 static const char * const hibernation_modes[] = {
 914         [HIBERNATION_PLATFORM]  = "platform",
 915         [HIBERNATION_SHUTDOWN]  = "shutdown",
 916         [HIBERNATION_REBOOT]    = "reboot",
 917 #ifdef CONFIG_SUSPEND
 918         [HIBERNATION_SUSPEND]   = "suspend",
 919 #endif
 920         [HIBERNATION_TEST_RESUME]       = "test_resume",
 921 };
 922
 923 /*
 924  * /sys/power/disk - Control hibernation mode.
 925  *
 926  * Hibernation can be handled in several ways.  There are a few different ways
 927  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 928  * or other hibernation_ops), powering it off or rebooting it (for testing
 929  * mostly).
 930  *
 931  * The sysfs file /sys/power/disk provides an interface for selecting the
 932  * hibernation mode to use.  Reading from this file causes the available modes
 933  * to be printed.  There are 3 modes that can be supported:
 934  *
 935  *      'platform'
 936  *      'shutdown'
 937  *      'reboot'
 938  *
 939  * If a platform hibernation driver is in use, 'platform' will be supported
 940  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 941  * The selected option (i.e. the one corresponding to the current value of
 942  * hibernation_mode) is enclosed by a square bracket.
 943  *
 944  * To select a given hibernation mode it is necessary to write the mode's
 945  * string representation (as returned by reading from /sys/power/disk) back
 946  * into /sys/power/disk.
 947  */
 948
 949 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 950                          char *buf)
 951 {
 952         int i;
 953         char *start = buf;
 954
 955         if (!hibernation_available())
 956                 return sprintf(buf, "[disabled]\n");
 957
 958         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 959                 if (!hibernation_modes[i])
 960                         continue;
 961                 switch (i) {
 962                 case HIBERNATION_SHUTDOWN:
 963                 case HIBERNATION_REBOOT:
 964 #ifdef CONFIG_SUSPEND
 965                 case HIBERNATION_SUSPEND:
 966 #endif
 967                 case HIBERNATION_TEST_RESUME:
 968                         break;
 969                 case HIBERNATION_PLATFORM:
 970                         if (hibernation_ops)
 971                                 break;
 972                         /* not a valid mode, continue with loop */
 973                         continue;
 974                 }
 975                 if (i == hibernation_mode)
 976                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 977                 else
 978                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 979         }
 980         buf += sprintf(buf, "\n");
 981         return buf-start;
 982 }
 983
 984 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 985                           const char *buf, size_t n)
 986 {
 987         int error = 0;
 988         int i;
 989         int len;
 990         char *p;
 991         int mode = HIBERNATION_INVALID;
 992
 993         if (!hibernation_available())
 994                 return -EPERM;
 995
 996         p = memchr(buf, '\n', n);
 997         len = p ? p - buf : n;
 998
 999         lock_system_sleep();
1000         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1001                 if (len == strlen(hibernation_modes[i])
1002                     && !strncmp(buf, hibernation_modes[i], len)) {
1003                         mode = i;
1004                         break;
1005                 }
1006         }
1007         if (mode != HIBERNATION_INVALID) {
1008                 switch (mode) {
1009                 case HIBERNATION_SHUTDOWN:
1010                 case HIBERNATION_REBOOT:
1011 #ifdef CONFIG_SUSPEND
1012                 case HIBERNATION_SUSPEND:
1013 #endif
1014                 case HIBERNATION_TEST_RESUME:
1015                         hibernation_mode = mode;
1016                         break;
1017                 case HIBERNATION_PLATFORM:
1018                         if (hibernation_ops)
1019                                 hibernation_mode = mode;
1020                         else
1021                                 error = -EINVAL;
1022                 }
1023         } else
1024                 error = -EINVAL;
1025
1026         if (!error)
1027                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1028                                hibernation_modes[mode]);
1029         unlock_system_sleep();
1030         return error ? error : n;
1031 }
1032
1033 power_attr(disk);
1034
1035 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1036                            char *buf)
1037 {
1038         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1039                        MINOR(swsusp_resume_device));
1040 }
1041
1042 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1043                             const char *buf, size_t n)
1044 {
1045         dev_t res;
1046         int len = n;
1047         char *name;
1048
1049         if (len && buf[len-1] == '\n')
1050                 len--;
1051         name = kstrndup(buf, len, GFP_KERNEL);
1052         if (!name)
1053                 return -ENOMEM;
1054
1055         res = name_to_dev_t(name);
1056         kfree(name);
1057         if (!res)
1058                 return -EINVAL;
1059
1060         lock_system_sleep();
1061         swsusp_resume_device = res;
1062         unlock_system_sleep();
1063         pm_pr_dbg("Configured resume from disk to %u\n", swsusp_resume_device);
1064         noresume = 0;
1065         software_resume();
1066         return n;
1067 }
1068
1069 power_attr(resume);
1070
1071 static ssize_t resume_offset_show(struct kobject *kobj,
1072                                   struct kobj_attribute *attr, char *buf)
1073 {
1074         return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1075 }
1076
1077 static ssize_t resume_offset_store(struct kobject *kobj,
1078                                    struct kobj_attribute *attr, const char *buf,
1079                                    size_t n)
1080 {
1081         unsigned long long offset;
1082         int rc;
1083
1084         rc = kstrtoull(buf, 0, &offset);
1085         if (rc)
1086                 return rc;
1087         swsusp_resume_block = offset;
1088
1089         return n;
1090 }
1091
1092 power_attr(resume_offset);
1093
1094 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1095                                char *buf)
1096 {
1097         return sprintf(buf, "%lu\n", image_size);
1098 }
1099
1100 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1101                                 const char *buf, size_t n)
1102 {
1103         unsigned long size;
1104
1105         if (sscanf(buf, "%lu", &size) == 1) {
1106                 image_size = size;
1107                 return n;
1108         }
1109
1110         return -EINVAL;
1111 }
1112
1113 power_attr(image_size);
1114
1115 static ssize_t reserved_size_show(struct kobject *kobj,
1116                                   struct kobj_attribute *attr, char *buf)
1117 {
1118         return sprintf(buf, "%lu\n", reserved_size);
1119 }
1120
1121 static ssize_t reserved_size_store(struct kobject *kobj,
1122                                    struct kobj_attribute *attr,
1123                                    const char *buf, size_t n)
1124 {
1125         unsigned long size;
1126
1127         if (sscanf(buf, "%lu", &size) == 1) {
1128                 reserved_size = size;
1129                 return n;
1130         }
1131
1132         return -EINVAL;
1133 }
1134
1135 power_attr(reserved_size);
1136
1137 static struct attribute * g[] = {
1138         &disk_attr.attr,
1139         &resume_offset_attr.attr,
1140         &resume_attr.attr,
1141         &image_size_attr.attr,
1142         &reserved_size_attr.attr,
1143         NULL,
1144 };
1145
1146
1147 static const struct attribute_group attr_group = {
1148         .attrs = g,
1149 };
1150
1151
1152 static int __init pm_disk_init(void)
1153 {
1154         return sysfs_create_group(power_kobj, &attr_group);
1155 }
1156
1157 core_initcall(pm_disk_init);
1158
1159
1160 static int __init resume_setup(char *str)
1161 {
1162         if (noresume)
1163                 return 1;
1164
1165         strncpy( resume_file, str, 255 );
1166         return 1;
1167 }
1168
1169 static int __init resume_offset_setup(char *str)
1170 {
1171         unsigned long long offset;
1172
1173         if (noresume)
1174                 return 1;
1175
1176         if (sscanf(str, "%llu", &offset) == 1)
1177                 swsusp_resume_block = offset;
1178
1179         return 1;
1180 }
1181
1182 static int __init hibernate_setup(char *str)
1183 {
1184         if (!strncmp(str, "noresume", 8)) {
1185                 noresume = 1;
1186         } else if (!strncmp(str, "nocompress", 10)) {
1187                 nocompress = 1;
1188         } else if (!strncmp(str, "no", 2)) {
1189                 noresume = 1;
1190                 nohibernate = 1;
1191         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1192                    && !strncmp(str, "protect_image", 13)) {
1193                 enable_restore_image_protection();
1194         }
1195         return 1;
1196 }
1197
1198 static int __init noresume_setup(char *str)
1199 {
1200         noresume = 1;
1201         return 1;
1202 }
1203
1204 static int __init resumewait_setup(char *str)
1205 {
1206         resume_wait = 1;
1207         return 1;
1208 }
1209
1210 static int __init resumedelay_setup(char *str)
1211 {
1212         int rc = kstrtouint(str, 0, &resume_delay);
1213
1214         if (rc)
1215                 return rc;
1216         return 1;
1217 }
1218
1219 static int __init nohibernate_setup(char *str)
1220 {
1221         noresume = 1;
1222         nohibernate = 1;
1223         return 1;
1224 }
1225
1226 __setup("noresume", noresume_setup);
1227 __setup("resume_offset=", resume_offset_setup);
1228 __setup("resume=", resume_setup);
1229 __setup("hibernate=", hibernate_setup);
1230 __setup("resumewait", resumewait_setup);
1231 __setup("resumedelay=", resumedelay_setup);
1232 __setup("nohibernate", nohibernate_setup);