kernel/kernel/power/hibernate.c

   1 /*
   2  * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   7  * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   8  * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
   9  *
  10  * This file is released under the GPLv2.
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/suspend.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/reboot.h>
  17 #include <linux/string.h>
  18 #include <linux/device.h>
  19 #include <linux/async.h>
  20 #include <linux/delay.h>
  21 #include <linux/fs.h>
  22 #include <linux/mount.h>
  23 #include <linux/pm.h>
  24 #include <linux/console.h>
  25 #include <linux/cpu.h>
  26 #include <linux/freezer.h>
  27 #include <linux/gfp.h>
  28 #include <linux/syscore_ops.h>
  29 #include <linux/ctype.h>
  30 #include <linux/genhd.h>
  31 #include <linux/ktime.h>
  32 #include <trace/events/power.h>
  33
  34 #include "power.h"
  35
  36
  37 static int nocompress;
  38 static int noresume;
  39 static int nohibernate;
  40 static int resume_wait;
  41 static unsigned int resume_delay;
  42 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  43 dev_t swsusp_resume_device;
  44 sector_t swsusp_resume_block;
  45 __visible int in_suspend __nosavedata;
  46
  47 enum {
  48         HIBERNATION_INVALID,
  49         HIBERNATION_PLATFORM,
  50         HIBERNATION_SHUTDOWN,
  51         HIBERNATION_REBOOT,
  52 #ifdef CONFIG_SUSPEND
  53         HIBERNATION_SUSPEND,
  54 #endif
  55         /* keep last */
  56         __HIBERNATION_AFTER_LAST
  57 };
  58 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  59 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  60
  61 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  62
  63 bool freezer_test_done;
  64
  65 static const struct platform_hibernation_ops *hibernation_ops;
  66
  67 bool hibernation_available(void)
  68 {
  69         return (nohibernate == 0);
  70 }
  71
  72 /**
  73  * hibernation_set_ops - Set the global hibernate operations.
  74  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  75  */
  76 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  77 {
  78         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  79             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  80             && ops->restore_cleanup && ops->leave)) {
  81                 WARN_ON(1);
  82                 return;
  83         }
  84         lock_system_sleep();
  85         hibernation_ops = ops;
  86         if (ops)
  87                 hibernation_mode = HIBERNATION_PLATFORM;
  88         else if (hibernation_mode == HIBERNATION_PLATFORM)
  89                 hibernation_mode = HIBERNATION_SHUTDOWN;
  90
  91         unlock_system_sleep();
  92 }
  93 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  94
  95 static bool entering_platform_hibernation;
  96
  97 bool system_entering_hibernation(void)
  98 {
  99         return entering_platform_hibernation;
 100 }
 101 EXPORT_SYMBOL(system_entering_hibernation);
 102
 103 #ifdef CONFIG_PM_DEBUG
 104 static void hibernation_debug_sleep(void)
 105 {
 106         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 107         mdelay(5000);
 108 }
 109
 110 static int hibernation_test(int level)
 111 {
 112         if (pm_test_level == level) {
 113                 hibernation_debug_sleep();
 114                 return 1;
 115         }
 116         return 0;
 117 }
 118 #else /* !CONFIG_PM_DEBUG */
 119 static int hibernation_test(int level) { return 0; }
 120 #endif /* !CONFIG_PM_DEBUG */
 121
 122 /**
 123  * platform_begin - Call platform to start hibernation.
 124  * @platform_mode: Whether or not to use the platform driver.
 125  */
 126 static int platform_begin(int platform_mode)
 127 {
 128         return (platform_mode && hibernation_ops) ?
 129                 hibernation_ops->begin() : 0;
 130 }
 131
 132 /**
 133  * platform_end - Call platform to finish transition to the working state.
 134  * @platform_mode: Whether or not to use the platform driver.
 135  */
 136 static void platform_end(int platform_mode)
 137 {
 138         if (platform_mode && hibernation_ops)
 139                 hibernation_ops->end();
 140 }
 141
 142 /**
 143  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 144  * @platform_mode: Whether or not to use the platform driver.
 145  *
 146  * Use the platform driver to prepare the system for creating a hibernate image,
 147  * if so configured, and return an error code if that fails.
 148  */
 149
 150 static int platform_pre_snapshot(int platform_mode)
 151 {
 152         return (platform_mode && hibernation_ops) ?
 153                 hibernation_ops->pre_snapshot() : 0;
 154 }
 155
 156 /**
 157  * platform_leave - Call platform to prepare a transition to the working state.
 158  * @platform_mode: Whether or not to use the platform driver.
 159  *
 160  * Use the platform driver prepare to prepare the machine for switching to the
 161  * normal mode of operation.
 162  *
 163  * This routine is called on one CPU with interrupts disabled.
 164  */
 165 static void platform_leave(int platform_mode)
 166 {
 167         if (platform_mode && hibernation_ops)
 168                 hibernation_ops->leave();
 169 }
 170
 171 /**
 172  * platform_finish - Call platform to switch the system to the working state.
 173  * @platform_mode: Whether or not to use the platform driver.
 174  *
 175  * Use the platform driver to switch the machine to the normal mode of
 176  * operation.
 177  *
 178  * This routine must be called after platform_prepare().
 179  */
 180 static void platform_finish(int platform_mode)
 181 {
 182         if (platform_mode && hibernation_ops)
 183                 hibernation_ops->finish();
 184 }
 185
 186 /**
 187  * platform_pre_restore - Prepare for hibernate image restoration.
 188  * @platform_mode: Whether or not to use the platform driver.
 189  *
 190  * Use the platform driver to prepare the system for resume from a hibernation
 191  * image.
 192  *
 193  * If the restore fails after this function has been called,
 194  * platform_restore_cleanup() must be called.
 195  */
 196 static int platform_pre_restore(int platform_mode)
 197 {
 198         return (platform_mode && hibernation_ops) ?
 199                 hibernation_ops->pre_restore() : 0;
 200 }
 201
 202 /**
 203  * platform_restore_cleanup - Switch to the working state after failing restore.
 204  * @platform_mode: Whether or not to use the platform driver.
 205  *
 206  * Use the platform driver to switch the system to the normal mode of operation
 207  * after a failing restore.
 208  *
 209  * If platform_pre_restore() has been called before the failing restore, this
 210  * function must be called too, regardless of the result of
 211  * platform_pre_restore().
 212  */
 213 static void platform_restore_cleanup(int platform_mode)
 214 {
 215         if (platform_mode && hibernation_ops)
 216                 hibernation_ops->restore_cleanup();
 217 }
 218
 219 /**
 220  * platform_recover - Recover from a failure to suspend devices.
 221  * @platform_mode: Whether or not to use the platform driver.
 222  */
 223 static void platform_recover(int platform_mode)
 224 {
 225         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 226                 hibernation_ops->recover();
 227 }
 228
 229 /**
 230  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 231  * @start: Starting event.
 232  * @stop: Final event.
 233  * @nr_pages: Number of memory pages processed between @start and @stop.
 234  * @msg: Additional diagnostic message to print.
 235  */
 236 void swsusp_show_speed(ktime_t start, ktime_t stop,
 237                       unsigned nr_pages, char *msg)
 238 {
 239         ktime_t diff;
 240         u64 elapsed_centisecs64;
 241         unsigned int centisecs;
 242         unsigned int k;
 243         unsigned int kps;
 244
 245         diff = ktime_sub(stop, start);
 246         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 247         centisecs = elapsed_centisecs64;
 248         if (centisecs == 0)
 249                 centisecs = 1;  /* avoid div-by-zero */
 250         k = nr_pages * (PAGE_SIZE / 1024);
 251         kps = (k * 100) / centisecs;
 252         printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 253                         msg, k,
 254                         centisecs / 100, centisecs % 100,
 255                         kps / 1000, (kps % 1000) / 10);
 256 }
 257
 258 /**
 259  * create_image - Create a hibernation image.
 260  * @platform_mode: Whether or not to use the platform driver.
 261  *
 262  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 263  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 264  *
 265  * Control reappears in this routine after the subsequent restore.
 266  */
 267 static int create_image(int platform_mode)
 268 {
 269         int error;
 270
 271         error = dpm_suspend_end(PMSG_FREEZE);
 272         if (error) {
 273                 printk(KERN_ERR "PM: Some devices failed to power down, "
 274                         "aborting hibernation\n");
 275                 return error;
 276         }
 277
 278         error = platform_pre_snapshot(platform_mode);
 279         if (error || hibernation_test(TEST_PLATFORM))
 280                 goto Platform_finish;
 281
 282         error = disable_nonboot_cpus();
 283         if (error || hibernation_test(TEST_CPUS))
 284                 goto Enable_cpus;
 285
 286         local_irq_disable();
 287
 288         system_state = SYSTEM_SUSPEND;
 289
 290         error = syscore_suspend();
 291         if (error) {
 292                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 293                         "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                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 309                         error);
 310         if (!in_suspend)
 311                 events_check_enabled = false;
 312
 313         platform_leave(platform_mode);
 314
 315  Power_up:
 316         syscore_resume();
 317
 318  Enable_irqs:
 319         system_state = SYSTEM_RUNNING;
 320         local_irq_enable();
 321
 322  Enable_cpus:
 323         enable_nonboot_cpus();
 324
 325  Platform_finish:
 326         platform_finish(platform_mode);
 327
 328         dpm_resume_start(in_suspend ?
 329                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 330
 331         return error;
 332 }
 333
 334 /**
 335  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 336  * @platform_mode: If set, use platform driver to prepare for the transition.
 337  *
 338  * This routine must be called with pm_mutex held.
 339  */
 340 int hibernation_snapshot(int platform_mode)
 341 {
 342         pm_message_t msg;
 343         int error;
 344
 345         pm_suspend_clear_flags();
 346         error = platform_begin(platform_mode);
 347         if (error)
 348                 goto Close;
 349
 350         /* Preallocate image memory before shutting down devices. */
 351         error = hibernate_preallocate_memory();
 352         if (error)
 353                 goto Close;
 354
 355         error = freeze_kernel_threads();
 356         if (error)
 357                 goto Cleanup;
 358
 359         if (hibernation_test(TEST_FREEZER)) {
 360
 361                 /*
 362                  * Indicate to the caller that we are returning due to a
 363                  * successful freezer test.
 364                  */
 365                 freezer_test_done = true;
 366                 goto Thaw;
 367         }
 368
 369         error = dpm_prepare(PMSG_FREEZE);
 370         if (error) {
 371                 dpm_complete(PMSG_RECOVER);
 372                 goto Thaw;
 373         }
 374
 375         suspend_console();
 376         pm_restrict_gfp_mask();
 377
 378         error = dpm_suspend(PMSG_FREEZE);
 379
 380         if (error || hibernation_test(TEST_DEVICES))
 381                 platform_recover(platform_mode);
 382         else
 383                 error = create_image(platform_mode);
 384
 385         /*
 386          * In the case that we call create_image() above, the control
 387          * returns here (1) after the image has been created or the
 388          * image creation has failed and (2) after a successful restore.
 389          */
 390
 391         /* We may need to release the preallocated image pages here. */
 392         if (error || !in_suspend)
 393                 swsusp_free();
 394
 395         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 396         dpm_resume(msg);
 397
 398         if (error || !in_suspend)
 399                 pm_restore_gfp_mask();
 400
 401         resume_console();
 402         dpm_complete(msg);
 403
 404  Close:
 405         platform_end(platform_mode);
 406         return error;
 407
 408  Thaw:
 409         thaw_kernel_threads();
 410  Cleanup:
 411         swsusp_free();
 412         goto Close;
 413 }
 414
 415 /**
 416  * resume_target_kernel - Restore system state from a hibernation image.
 417  * @platform_mode: Whether or not to use the platform driver.
 418  *
 419  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 420  * contents of highmem that have not been restored yet from the image and run
 421  * the low-level code that will restore the remaining contents of memory and
 422  * switch to the just restored target kernel.
 423  */
 424 static int resume_target_kernel(bool platform_mode)
 425 {
 426         int error;
 427
 428         error = dpm_suspend_end(PMSG_QUIESCE);
 429         if (error) {
 430                 printk(KERN_ERR "PM: Some devices failed to power down, "
 431                         "aborting resume\n");
 432                 return error;
 433         }
 434
 435         error = platform_pre_restore(platform_mode);
 436         if (error)
 437                 goto Cleanup;
 438
 439         error = disable_nonboot_cpus();
 440         if (error)
 441                 goto Enable_cpus;
 442
 443         local_irq_disable();
 444         system_state = SYSTEM_SUSPEND;
 445
 446         error = syscore_suspend();
 447         if (error)
 448                 goto Enable_irqs;
 449
 450         save_processor_state();
 451         error = restore_highmem();
 452         if (!error) {
 453                 error = swsusp_arch_resume();
 454                 /*
 455                  * The code below is only ever reached in case of a failure.
 456                  * Otherwise, execution continues at the place where
 457                  * swsusp_arch_suspend() was called.
 458                  */
 459                 BUG_ON(!error);
 460                 /*
 461                  * This call to restore_highmem() reverts the changes made by
 462                  * the previous one.
 463                  */
 464                 restore_highmem();
 465         }
 466         /*
 467          * The only reason why swsusp_arch_resume() can fail is memory being
 468          * very tight, so we have to free it as soon as we can to avoid
 469          * subsequent failures.
 470          */
 471         swsusp_free();
 472         restore_processor_state();
 473         touch_softlockup_watchdog();
 474
 475         syscore_resume();
 476
 477  Enable_irqs:
 478         system_state = SYSTEM_RUNNING;
 479         local_irq_enable();
 480
 481  Enable_cpus:
 482         enable_nonboot_cpus();
 483
 484  Cleanup:
 485         platform_restore_cleanup(platform_mode);
 486
 487         dpm_resume_start(PMSG_RECOVER);
 488
 489         return error;
 490 }
 491
 492 /**
 493  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 494  * @platform_mode: If set, use platform driver to prepare for the transition.
 495  *
 496  * This routine must be called with pm_mutex held.  If it is successful, control
 497  * reappears in the restored target kernel in hibernation_snapshot().
 498  */
 499 int hibernation_restore(int platform_mode)
 500 {
 501         int error;
 502
 503         pm_prepare_console();
 504         suspend_console();
 505         pm_restrict_gfp_mask();
 506         error = dpm_suspend_start(PMSG_QUIESCE);
 507         if (!error) {
 508                 error = resume_target_kernel(platform_mode);
 509                 /*
 510                  * The above should either succeed and jump to the new kernel,
 511                  * or return with an error. Otherwise things are just
 512                  * undefined, so let's be paranoid.
 513                  */
 514                 BUG_ON(!error);
 515         }
 516         dpm_resume_end(PMSG_RECOVER);
 517         pm_restore_gfp_mask();
 518         resume_console();
 519         pm_restore_console();
 520         return error;
 521 }
 522
 523 /**
 524  * hibernation_platform_enter - Power off the system using the platform driver.
 525  */
 526 int hibernation_platform_enter(void)
 527 {
 528         int error;
 529
 530         if (!hibernation_ops)
 531                 return -ENOSYS;
 532
 533         /*
 534          * We have cancelled the power transition by running
 535          * hibernation_ops->finish() before saving the image, so we should let
 536          * the firmware know that we're going to enter the sleep state after all
 537          */
 538         error = hibernation_ops->begin();
 539         if (error)
 540                 goto Close;
 541
 542         entering_platform_hibernation = true;
 543         suspend_console();
 544         error = dpm_suspend_start(PMSG_HIBERNATE);
 545         if (error) {
 546                 if (hibernation_ops->recover)
 547                         hibernation_ops->recover();
 548                 goto Resume_devices;
 549         }
 550
 551         error = dpm_suspend_end(PMSG_HIBERNATE);
 552         if (error)
 553                 goto Resume_devices;
 554
 555         error = hibernation_ops->prepare();
 556         if (error)
 557                 goto Platform_finish;
 558
 559         error = disable_nonboot_cpus();
 560         if (error)
 561                 goto Enable_cpus;
 562
 563         local_irq_disable();
 564         system_state = SYSTEM_SUSPEND;
 565         syscore_suspend();
 566         if (pm_wakeup_pending()) {
 567                 error = -EAGAIN;
 568                 goto Power_up;
 569         }
 570
 571         hibernation_ops->enter();
 572         /* We should never get here */
 573         while (1);
 574
 575  Power_up:
 576         syscore_resume();
 577         system_state = SYSTEM_RUNNING;
 578         local_irq_enable();
 579
 580  Enable_cpus:
 581         enable_nonboot_cpus();
 582
 583  Platform_finish:
 584         hibernation_ops->finish();
 585
 586         dpm_resume_start(PMSG_RESTORE);
 587
 588  Resume_devices:
 589         entering_platform_hibernation = false;
 590         dpm_resume_end(PMSG_RESTORE);
 591         resume_console();
 592
 593  Close:
 594         hibernation_ops->end();
 595
 596         return error;
 597 }
 598
 599 /**
 600  * power_down - Shut the machine down for hibernation.
 601  *
 602  * Use the platform driver, if configured, to put the system into the sleep
 603  * state corresponding to hibernation, or try to power it off or reboot,
 604  * depending on the value of hibernation_mode.
 605  */
 606 static void power_down(void)
 607 {
 608 #ifdef CONFIG_SUSPEND
 609         int error;
 610 #endif
 611
 612         switch (hibernation_mode) {
 613         case HIBERNATION_REBOOT:
 614                 kernel_restart(NULL);
 615                 break;
 616         case HIBERNATION_PLATFORM:
 617                 hibernation_platform_enter();
 618         case HIBERNATION_SHUTDOWN:
 619                 if (pm_power_off)
 620                         kernel_power_off();
 621                 break;
 622 #ifdef CONFIG_SUSPEND
 623         case HIBERNATION_SUSPEND:
 624                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 625                 if (error) {
 626                         if (hibernation_ops)
 627                                 hibernation_mode = HIBERNATION_PLATFORM;
 628                         else
 629                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 630                         power_down();
 631                 }
 632                 /*
 633                  * Restore swap signature.
 634                  */
 635                 error = swsusp_unmark();
 636                 if (error)
 637                         printk(KERN_ERR "PM: Swap will be unusable! "
 638                                         "Try swapon -a.\n");
 639                 return;
 640 #endif
 641         }
 642         kernel_halt();
 643         /*
 644          * Valid image is on the disk, if we continue we risk serious data
 645          * corruption after resume.
 646          */
 647         printk(KERN_CRIT "PM: Please power down manually\n");
 648         while (1)
 649                 cpu_relax();
 650 }
 651
 652 #ifndef CONFIG_SUSPEND
 653 bool pm_in_action;
 654 #endif
 655
 656 /**
 657  * hibernate - Carry out system hibernation, including saving the image.
 658  */
 659 int hibernate(void)
 660 {
 661         int error;
 662
 663         if (!hibernation_available()) {
 664                 pr_debug("PM: Hibernation not available.\n");
 665                 return -EPERM;
 666         }
 667
 668         pm_in_action = true;
 669
 670         lock_system_sleep();
 671         /* The snapshot device should not be opened while we're running */
 672         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 673                 error = -EBUSY;
 674                 goto Unlock;
 675         }
 676
 677         pm_prepare_console();
 678         error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 679         if (error)
 680                 goto Exit;
 681
 682         printk(KERN_INFO "PM: Syncing filesystems ... ");
 683         sys_sync();
 684         printk("done.\n");
 685
 686         error = freeze_processes();
 687         if (error)
 688                 goto Exit;
 689
 690         lock_device_hotplug();
 691         /* Allocate memory management structures */
 692         error = create_basic_memory_bitmaps();
 693         if (error)
 694                 goto Thaw;
 695
 696         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 697         if (error || freezer_test_done)
 698                 goto Free_bitmaps;
 699
 700         if (in_suspend) {
 701                 unsigned int flags = 0;
 702
 703                 if (hibernation_mode == HIBERNATION_PLATFORM)
 704                         flags |= SF_PLATFORM_MODE;
 705                 if (nocompress)
 706                         flags |= SF_NOCOMPRESS_MODE;
 707                 else
 708                         flags |= SF_CRC32_MODE;
 709
 710                 pr_debug("PM: writing image.\n");
 711                 error = swsusp_write(flags);
 712                 swsusp_free();
 713                 if (!error)
 714                         power_down();
 715                 in_suspend = 0;
 716                 pm_restore_gfp_mask();
 717         } else {
 718                 pr_debug("PM: Image restored successfully.\n");
 719         }
 720
 721  Free_bitmaps:
 722         free_basic_memory_bitmaps();
 723  Thaw:
 724         unlock_device_hotplug();
 725         thaw_processes();
 726
 727         /* Don't bother checking whether freezer_test_done is true */
 728         freezer_test_done = false;
 729  Exit:
 730         pm_notifier_call_chain(PM_POST_HIBERNATION);
 731         pm_restore_console();
 732         atomic_inc(&snapshot_device_available);
 733  Unlock:
 734         unlock_system_sleep();
 735         pm_in_action = false;
 736         return error;
 737 }
 738
 739
 740 /**
 741  * software_resume - Resume from a saved hibernation image.
 742  *
 743  * This routine is called as a late initcall, when all devices have been
 744  * discovered and initialized already.
 745  *
 746  * The image reading code is called to see if there is a hibernation image
 747  * available for reading.  If that is the case, devices are quiesced and the
 748  * contents of memory is restored from the saved image.
 749  *
 750  * If this is successful, control reappears in the restored target kernel in
 751  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 752  * attempts to recover gracefully and make the kernel return to the normal mode
 753  * of operation.
 754  */
 755 static int software_resume(void)
 756 {
 757         int error;
 758         unsigned int flags;
 759
 760         /*
 761          * If the user said "noresume".. bail out early.
 762          */
 763         if (noresume || !hibernation_available())
 764                 return 0;
 765
 766         /*
 767          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 768          * is configured into the kernel. Since the regular hibernate
 769          * trigger path is via sysfs which takes a buffer mutex before
 770          * calling hibernate functions (which take pm_mutex) this can
 771          * cause lockdep to complain about a possible ABBA deadlock
 772          * which cannot happen since we're in the boot code here and
 773          * sysfs can't be invoked yet. Therefore, we use a subclass
 774          * here to avoid lockdep complaining.
 775          */
 776         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 777
 778         if (swsusp_resume_device)
 779                 goto Check_image;
 780
 781         if (!strlen(resume_file)) {
 782                 error = -ENOENT;
 783                 goto Unlock;
 784         }
 785
 786         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 787
 788         if (resume_delay) {
 789                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 790                         resume_delay);
 791                 ssleep(resume_delay);
 792         }
 793
 794         /* Check if the device is there */
 795         swsusp_resume_device = name_to_dev_t(resume_file);
 796
 797         /*
 798          * name_to_dev_t is ineffective to verify parition if resume_file is in
 799          * integer format. (e.g. major:minor)
 800          */
 801         if (isdigit(resume_file[0]) && resume_wait) {
 802                 int partno;
 803                 while (!get_gendisk(swsusp_resume_device, &partno))
 804                         msleep(10);
 805         }
 806
 807         if (!swsusp_resume_device) {
 808                 /*
 809                  * Some device discovery might still be in progress; we need
 810                  * to wait for this to finish.
 811                  */
 812                 wait_for_device_probe();
 813
 814                 if (resume_wait) {
 815                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 816                                 msleep(10);
 817                         async_synchronize_full();
 818                 }
 819
 820                 swsusp_resume_device = name_to_dev_t(resume_file);
 821                 if (!swsusp_resume_device) {
 822                         error = -ENODEV;
 823                         goto Unlock;
 824                 }
 825         }
 826
 827  Check_image:
 828         pr_debug("PM: Hibernation image partition %d:%d present\n",
 829                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 830
 831         pr_debug("PM: Looking for hibernation image.\n");
 832         error = swsusp_check();
 833         if (error)
 834                 goto Unlock;
 835
 836         /* The snapshot device should not be opened while we're running */
 837         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 838                 error = -EBUSY;
 839                 swsusp_close(FMODE_READ);
 840                 goto Unlock;
 841         }
 842
 843         pm_prepare_console();
 844         error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 845         if (error)
 846                 goto Close_Finish;
 847
 848         pr_debug("PM: Preparing processes for restore.\n");
 849         error = freeze_processes();
 850         if (error)
 851                 goto Close_Finish;
 852
 853         pr_debug("PM: Loading hibernation image.\n");
 854
 855         lock_device_hotplug();
 856         error = create_basic_memory_bitmaps();
 857         if (error)
 858                 goto Thaw;
 859
 860         error = swsusp_read(&flags);
 861         swsusp_close(FMODE_READ);
 862         if (!error)
 863                 hibernation_restore(flags & SF_PLATFORM_MODE);
 864
 865         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 866         swsusp_free();
 867         free_basic_memory_bitmaps();
 868  Thaw:
 869         unlock_device_hotplug();
 870         thaw_processes();
 871  Finish:
 872         pm_notifier_call_chain(PM_POST_RESTORE);
 873         pm_restore_console();
 874         atomic_inc(&snapshot_device_available);
 875         /* For success case, the suspend path will release the lock */
 876  Unlock:
 877         mutex_unlock(&pm_mutex);
 878         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 879         return error;
 880  Close_Finish:
 881         swsusp_close(FMODE_READ);
 882         goto Finish;
 883 }
 884
 885 late_initcall_sync(software_resume);
 886
 887
 888 static const char * const hibernation_modes[] = {
 889         [HIBERNATION_PLATFORM]  = "platform",
 890         [HIBERNATION_SHUTDOWN]  = "shutdown",
 891         [HIBERNATION_REBOOT]    = "reboot",
 892 #ifdef CONFIG_SUSPEND
 893         [HIBERNATION_SUSPEND]   = "suspend",
 894 #endif
 895 };
 896
 897 /*
 898  * /sys/power/disk - Control hibernation mode.
 899  *
 900  * Hibernation can be handled in several ways.  There are a few different ways
 901  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 902  * or other hibernation_ops), powering it off or rebooting it (for testing
 903  * mostly).
 904  *
 905  * The sysfs file /sys/power/disk provides an interface for selecting the
 906  * hibernation mode to use.  Reading from this file causes the available modes
 907  * to be printed.  There are 3 modes that can be supported:
 908  *
 909  *      'platform'
 910  *      'shutdown'
 911  *      'reboot'
 912  *
 913  * If a platform hibernation driver is in use, 'platform' will be supported
 914  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 915  * The selected option (i.e. the one corresponding to the current value of
 916  * hibernation_mode) is enclosed by a square bracket.
 917  *
 918  * To select a given hibernation mode it is necessary to write the mode's
 919  * string representation (as returned by reading from /sys/power/disk) back
 920  * into /sys/power/disk.
 921  */
 922
 923 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 924                          char *buf)
 925 {
 926         int i;
 927         char *start = buf;
 928
 929         if (!hibernation_available())
 930                 return sprintf(buf, "[disabled]\n");
 931
 932         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 933                 if (!hibernation_modes[i])
 934                         continue;
 935                 switch (i) {
 936                 case HIBERNATION_SHUTDOWN:
 937                 case HIBERNATION_REBOOT:
 938 #ifdef CONFIG_SUSPEND
 939                 case HIBERNATION_SUSPEND:
 940 #endif
 941                         break;
 942                 case HIBERNATION_PLATFORM:
 943                         if (hibernation_ops)
 944                                 break;
 945                         /* not a valid mode, continue with loop */
 946                         continue;
 947                 }
 948                 if (i == hibernation_mode)
 949                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 950                 else
 951                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 952         }
 953         buf += sprintf(buf, "\n");
 954         return buf-start;
 955 }
 956
 957 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 958                           const char *buf, size_t n)
 959 {
 960         int error = 0;
 961         int i;
 962         int len;
 963         char *p;
 964         int mode = HIBERNATION_INVALID;
 965
 966         if (!hibernation_available())
 967                 return -EPERM;
 968
 969         p = memchr(buf, '\n', n);
 970         len = p ? p - buf : n;
 971
 972         lock_system_sleep();
 973         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 974                 if (len == strlen(hibernation_modes[i])
 975                     && !strncmp(buf, hibernation_modes[i], len)) {
 976                         mode = i;
 977                         break;
 978                 }
 979         }
 980         if (mode != HIBERNATION_INVALID) {
 981                 switch (mode) {
 982                 case HIBERNATION_SHUTDOWN:
 983                 case HIBERNATION_REBOOT:
 984 #ifdef CONFIG_SUSPEND
 985                 case HIBERNATION_SUSPEND:
 986 #endif
 987                         hibernation_mode = mode;
 988                         break;
 989                 case HIBERNATION_PLATFORM:
 990                         if (hibernation_ops)
 991                                 hibernation_mode = mode;
 992                         else
 993                                 error = -EINVAL;
 994                 }
 995         } else
 996                 error = -EINVAL;
 997
 998         if (!error)
 999                 pr_debug("PM: Hibernation mode set to '%s'\n",
1000                          hibernation_modes[mode]);
1001         unlock_system_sleep();
1002         return error ? error : n;
1003 }
1004
1005 power_attr(disk);
1006
1007 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1008                            char *buf)
1009 {
1010         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1011                        MINOR(swsusp_resume_device));
1012 }
1013
1014 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1015                             const char *buf, size_t n)
1016 {
1017         dev_t res;
1018         int len = n;
1019         char *name;
1020
1021         if (len && buf[len-1] == '\n')
1022                 len--;
1023         name = kstrndup(buf, len, GFP_KERNEL);
1024         if (!name)
1025                 return -ENOMEM;
1026
1027         res = name_to_dev_t(name);
1028         kfree(name);
1029         if (!res)
1030                 return -EINVAL;
1031
1032         lock_system_sleep();
1033         swsusp_resume_device = res;
1034         unlock_system_sleep();
1035         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1036         noresume = 0;
1037         software_resume();
1038         return n;
1039 }
1040
1041 power_attr(resume);
1042
1043 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1044                                char *buf)
1045 {
1046         return sprintf(buf, "%lu\n", image_size);
1047 }
1048
1049 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1050                                 const char *buf, size_t n)
1051 {
1052         unsigned long size;
1053
1054         if (sscanf(buf, "%lu", &size) == 1) {
1055                 image_size = size;
1056                 return n;
1057         }
1058
1059         return -EINVAL;
1060 }
1061
1062 power_attr(image_size);
1063
1064 static ssize_t reserved_size_show(struct kobject *kobj,
1065                                   struct kobj_attribute *attr, char *buf)
1066 {
1067         return sprintf(buf, "%lu\n", reserved_size);
1068 }
1069
1070 static ssize_t reserved_size_store(struct kobject *kobj,
1071                                    struct kobj_attribute *attr,
1072                                    const char *buf, size_t n)
1073 {
1074         unsigned long size;
1075
1076         if (sscanf(buf, "%lu", &size) == 1) {
1077                 reserved_size = size;
1078                 return n;
1079         }
1080
1081         return -EINVAL;
1082 }
1083
1084 power_attr(reserved_size);
1085
1086 static struct attribute * g[] = {
1087         &disk_attr.attr,
1088         &resume_attr.attr,
1089         &image_size_attr.attr,
1090         &reserved_size_attr.attr,
1091         NULL,
1092 };
1093
1094
1095 static struct attribute_group attr_group = {
1096         .attrs = g,
1097 };
1098
1099
1100 static int __init pm_disk_init(void)
1101 {
1102         return sysfs_create_group(power_kobj, &attr_group);
1103 }
1104
1105 core_initcall(pm_disk_init);
1106
1107
1108 static int __init resume_setup(char *str)
1109 {
1110         if (noresume)
1111                 return 1;
1112
1113         strncpy( resume_file, str, 255 );
1114         return 1;
1115 }
1116
1117 static int __init resume_offset_setup(char *str)
1118 {
1119         unsigned long long offset;
1120
1121         if (noresume)
1122                 return 1;
1123
1124         if (sscanf(str, "%llu", &offset) == 1)
1125                 swsusp_resume_block = offset;
1126
1127         return 1;
1128 }
1129
1130 static int __init hibernate_setup(char *str)
1131 {
1132         if (!strncmp(str, "noresume", 8))
1133                 noresume = 1;
1134         else if (!strncmp(str, "nocompress", 10))
1135                 nocompress = 1;
1136         else if (!strncmp(str, "no", 2)) {
1137                 noresume = 1;
1138                 nohibernate = 1;
1139         }
1140         return 1;
1141 }
1142
1143 static int __init noresume_setup(char *str)
1144 {
1145         noresume = 1;
1146         return 1;
1147 }
1148
1149 static int __init resumewait_setup(char *str)
1150 {
1151         resume_wait = 1;
1152         return 1;
1153 }
1154
1155 static int __init resumedelay_setup(char *str)
1156 {
1157         int rc = kstrtouint(str, 0, &resume_delay);
1158
1159         if (rc)
1160                 return rc;
1161         return 1;
1162 }
1163
1164 static int __init nohibernate_setup(char *str)
1165 {
1166         noresume = 1;
1167         nohibernate = 1;
1168         return 1;
1169 }
1170
1171 static int __init kaslr_nohibernate_setup(char *str)
1172 {
1173         return nohibernate_setup(str);
1174 }
1175
1176 __setup("noresume", noresume_setup);
1177 __setup("resume_offset=", resume_offset_setup);
1178 __setup("resume=", resume_setup);
1179 __setup("hibernate=", hibernate_setup);
1180 __setup("resumewait", resumewait_setup);
1181 __setup("resumedelay=", resumedelay_setup);
1182 __setup("nohibernate", nohibernate_setup);
1183 __setup("kaslr", kaslr_nohibernate_setup);