kernel/power/hibernate.c

   1 /*
   2  * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   7  * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   8  * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
   9  *
  10  * This file is released under the GPLv2.
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/suspend.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/reboot.h>
  17 #include <linux/string.h>
  18 #include <linux/device.h>
  19 #include <linux/async.h>
  20 #include <linux/delay.h>
  21 #include <linux/fs.h>
  22 #include <linux/mount.h>
  23 #include <linux/pm.h>
  24 #include <linux/console.h>
  25 #include <linux/cpu.h>
  26 #include <linux/freezer.h>
  27 #include <linux/gfp.h>
  28 #include <linux/syscore_ops.h>
  29 #include <linux/ctype.h>
  30 #include <linux/genhd.h>
  31 #include <linux/ktime.h>
  32 #include <trace/events/power.h>
  33
  34 #include "power.h"
  35
  36
  37 static int nocompress;
  38 static int noresume;
  39 static int nohibernate;
  40 static int resume_wait;
  41 static unsigned int resume_delay;
  42 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  43 dev_t swsusp_resume_device;
  44 sector_t swsusp_resume_block;
  45 __visible int in_suspend __nosavedata;
  46
  47 enum {
  48         HIBERNATION_INVALID,
  49         HIBERNATION_PLATFORM,
  50         HIBERNATION_SHUTDOWN,
  51         HIBERNATION_REBOOT,
  52 #ifdef CONFIG_SUSPEND
  53         HIBERNATION_SUSPEND,
  54 #endif
  55         /* keep last */
  56         __HIBERNATION_AFTER_LAST
  57 };
  58 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  59 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  60
  61 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  62
  63 bool freezer_test_done;
  64
  65 static const struct platform_hibernation_ops *hibernation_ops;
  66
  67 bool hibernation_available(void)
  68 {
  69         return (nohibernate == 0);
  70 }
  71
  72 /**
  73  * hibernation_set_ops - Set the global hibernate operations.
  74  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  75  */
  76 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  77 {
  78         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  79             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  80             && ops->restore_cleanup && ops->leave)) {
  81                 WARN_ON(1);
  82                 return;
  83         }
  84         lock_system_sleep();
  85         hibernation_ops = ops;
  86         if (ops)
  87                 hibernation_mode = HIBERNATION_PLATFORM;
  88         else if (hibernation_mode == HIBERNATION_PLATFORM)
  89                 hibernation_mode = HIBERNATION_SHUTDOWN;
  90
  91         unlock_system_sleep();
  92 }
  93 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  94
  95 static bool entering_platform_hibernation;
  96
  97 bool system_entering_hibernation(void)
  98 {
  99         return entering_platform_hibernation;
 100 }
 101 EXPORT_SYMBOL(system_entering_hibernation);
 102
 103 #ifdef CONFIG_PM_DEBUG
 104 static void hibernation_debug_sleep(void)
 105 {
 106         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 107         mdelay(5000);
 108 }
 109
 110 static int hibernation_test(int level)
 111 {
 112         if (pm_test_level == level) {
 113                 hibernation_debug_sleep();
 114                 return 1;
 115         }
 116         return 0;
 117 }
 118 #else /* !CONFIG_PM_DEBUG */
 119 static int hibernation_test(int level) { return 0; }
 120 #endif /* !CONFIG_PM_DEBUG */
 121
 122 /**
 123  * platform_begin - Call platform to start hibernation.
 124  * @platform_mode: Whether or not to use the platform driver.
 125  */
 126 static int platform_begin(int platform_mode)
 127 {
 128         return (platform_mode && hibernation_ops) ?
 129                 hibernation_ops->begin() : 0;
 130 }
 131
 132 /**
 133  * platform_end - Call platform to finish transition to the working state.
 134  * @platform_mode: Whether or not to use the platform driver.
 135  */
 136 static void platform_end(int platform_mode)
 137 {
 138         if (platform_mode && hibernation_ops)
 139                 hibernation_ops->end();
 140 }
 141
 142 /**
 143  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 144  * @platform_mode: Whether or not to use the platform driver.
 145  *
 146  * Use the platform driver to prepare the system for creating a hibernate image,
 147  * if so configured, and return an error code if that fails.
 148  */
 149
 150 static int platform_pre_snapshot(int platform_mode)
 151 {
 152         return (platform_mode && hibernation_ops) ?
 153                 hibernation_ops->pre_snapshot() : 0;
 154 }
 155
 156 /**
 157  * platform_leave - Call platform to prepare a transition to the working state.
 158  * @platform_mode: Whether or not to use the platform driver.
 159  *
 160  * Use the platform driver prepare to prepare the machine for switching to the
 161  * normal mode of operation.
 162  *
 163  * This routine is called on one CPU with interrupts disabled.
 164  */
 165 static void platform_leave(int platform_mode)
 166 {
 167         if (platform_mode && hibernation_ops)
 168                 hibernation_ops->leave();
 169 }
 170
 171 /**
 172  * platform_finish - Call platform to switch the system to the working state.
 173  * @platform_mode: Whether or not to use the platform driver.
 174  *
 175  * Use the platform driver to switch the machine to the normal mode of
 176  * operation.
 177  *
 178  * This routine must be called after platform_prepare().
 179  */
 180 static void platform_finish(int platform_mode)
 181 {
 182         if (platform_mode && hibernation_ops)
 183                 hibernation_ops->finish();
 184 }
 185
 186 /**
 187  * platform_pre_restore - Prepare for hibernate image restoration.
 188  * @platform_mode: Whether or not to use the platform driver.
 189  *
 190  * Use the platform driver to prepare the system for resume from a hibernation
 191  * image.
 192  *
 193  * If the restore fails after this function has been called,
 194  * platform_restore_cleanup() must be called.
 195  */
 196 static int platform_pre_restore(int platform_mode)
 197 {
 198         return (platform_mode && hibernation_ops) ?
 199                 hibernation_ops->pre_restore() : 0;
 200 }
 201
 202 /**
 203  * platform_restore_cleanup - Switch to the working state after failing restore.
 204  * @platform_mode: Whether or not to use the platform driver.
 205  *
 206  * Use the platform driver to switch the system to the normal mode of operation
 207  * after a failing restore.
 208  *
 209  * If platform_pre_restore() has been called before the failing restore, this
 210  * function must be called too, regardless of the result of
 211  * platform_pre_restore().
 212  */
 213 static void platform_restore_cleanup(int platform_mode)
 214 {
 215         if (platform_mode && hibernation_ops)
 216                 hibernation_ops->restore_cleanup();
 217 }
 218
 219 /**
 220  * platform_recover - Recover from a failure to suspend devices.
 221  * @platform_mode: Whether or not to use the platform driver.
 222  */
 223 static void platform_recover(int platform_mode)
 224 {
 225         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 226                 hibernation_ops->recover();
 227 }
 228
 229 /**
 230  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 231  * @start: Starting event.
 232  * @stop: Final event.
 233  * @nr_pages: Number of memory pages processed between @start and @stop.
 234  * @msg: Additional diagnostic message to print.
 235  */
 236 void swsusp_show_speed(ktime_t start, ktime_t stop,
 237                       unsigned nr_pages, char *msg)
 238 {
 239         ktime_t diff;
 240         u64 elapsed_centisecs64;
 241         unsigned int centisecs;
 242         unsigned int k;
 243         unsigned int kps;
 244
 245         diff = ktime_sub(stop, start);
 246         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 247         centisecs = elapsed_centisecs64;
 248         if (centisecs == 0)
 249                 centisecs = 1;  /* avoid div-by-zero */
 250         k = nr_pages * (PAGE_SIZE / 1024);
 251         kps = (k * 100) / centisecs;
 252         printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 253                         msg, k,
 254                         centisecs / 100, centisecs % 100,
 255                         kps / 1000, (kps % 1000) / 10);
 256 }
 257
 258 /**
 259  * create_image - Create a hibernation image.
 260  * @platform_mode: Whether or not to use the platform driver.
 261  *
 262  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 263  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 264  *
 265  * Control reappears in this routine after the subsequent restore.
 266  */
 267 static int create_image(int platform_mode)
 268 {
 269         int error;
 270
 271         error = dpm_suspend_end(PMSG_FREEZE);
 272         if (error) {
 273                 printk(KERN_ERR "PM: Some devices failed to power down, "
 274                         "aborting hibernation\n");
 275                 return error;
 276         }
 277
 278         error = platform_pre_snapshot(platform_mode);
 279         if (error || hibernation_test(TEST_PLATFORM))
 280                 goto Platform_finish;
 281
 282         error = disable_nonboot_cpus();
 283         if (error || hibernation_test(TEST_CPUS))
 284                 goto Enable_cpus;
 285
 286         local_irq_disable();
 287
 288         error = syscore_suspend();
 289         if (error) {
 290                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 291                         "aborting hibernation\n");
 292                 goto Enable_irqs;
 293         }
 294
 295         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 296                 goto Power_up;
 297
 298         in_suspend = 1;
 299         save_processor_state();
 300         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 301         error = swsusp_arch_suspend();
 302         /* Restore control flow magically appears here */
 303         restore_processor_state();
 304         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 305         if (error)
 306                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 307                         error);
 308         if (!in_suspend)
 309                 events_check_enabled = false;
 310
 311         platform_leave(platform_mode);
 312
 313  Power_up:
 314         syscore_resume();
 315
 316  Enable_irqs:
 317         local_irq_enable();
 318
 319  Enable_cpus:
 320         enable_nonboot_cpus();
 321
 322  Platform_finish:
 323         platform_finish(platform_mode);
 324
 325         dpm_resume_start(in_suspend ?
 326                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 327
 328         return error;
 329 }
 330
 331 /**
 332  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 333  * @platform_mode: If set, use platform driver to prepare for the transition.
 334  *
 335  * This routine must be called with pm_mutex held.
 336  */
 337 int hibernation_snapshot(int platform_mode)
 338 {
 339         pm_message_t msg;
 340         int error;
 341
 342         pm_suspend_clear_flags();
 343         error = platform_begin(platform_mode);
 344         if (error)
 345                 goto Close;
 346
 347         /* Preallocate image memory before shutting down devices. */
 348         error = hibernate_preallocate_memory();
 349         if (error)
 350                 goto Close;
 351
 352         error = freeze_kernel_threads();
 353         if (error)
 354                 goto Cleanup;
 355
 356         if (hibernation_test(TEST_FREEZER)) {
 357
 358                 /*
 359                  * Indicate to the caller that we are returning due to a
 360                  * successful freezer test.
 361                  */
 362                 freezer_test_done = true;
 363                 goto Thaw;
 364         }
 365
 366         error = dpm_prepare(PMSG_FREEZE);
 367         if (error) {
 368                 dpm_complete(PMSG_RECOVER);
 369                 goto Thaw;
 370         }
 371
 372         suspend_console();
 373         pm_restrict_gfp_mask();
 374
 375         error = dpm_suspend(PMSG_FREEZE);
 376
 377         if (error || hibernation_test(TEST_DEVICES))
 378                 platform_recover(platform_mode);
 379         else
 380                 error = create_image(platform_mode);
 381
 382         /*
 383          * In the case that we call create_image() above, the control
 384          * returns here (1) after the image has been created or the
 385          * image creation has failed and (2) after a successful restore.
 386          */
 387
 388         /* We may need to release the preallocated image pages here. */
 389         if (error || !in_suspend)
 390                 swsusp_free();
 391
 392         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 393         dpm_resume(msg);
 394
 395         if (error || !in_suspend)
 396                 pm_restore_gfp_mask();
 397
 398         resume_console();
 399         dpm_complete(msg);
 400
 401  Close:
 402         platform_end(platform_mode);
 403         return error;
 404
 405  Thaw:
 406         thaw_kernel_threads();
 407  Cleanup:
 408         swsusp_free();
 409         goto Close;
 410 }
 411
 412 /**
 413  * resume_target_kernel - Restore system state from a hibernation image.
 414  * @platform_mode: Whether or not to use the platform driver.
 415  *
 416  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 417  * contents of highmem that have not been restored yet from the image and run
 418  * the low-level code that will restore the remaining contents of memory and
 419  * switch to the just restored target kernel.
 420  */
 421 static int resume_target_kernel(bool platform_mode)
 422 {
 423         int error;
 424
 425         error = dpm_suspend_end(PMSG_QUIESCE);
 426         if (error) {
 427                 printk(KERN_ERR "PM: Some devices failed to power down, "
 428                         "aborting resume\n");
 429                 return error;
 430         }
 431
 432         error = platform_pre_restore(platform_mode);
 433         if (error)
 434                 goto Cleanup;
 435
 436         error = disable_nonboot_cpus();
 437         if (error)
 438                 goto Enable_cpus;
 439
 440         local_irq_disable();
 441
 442         error = syscore_suspend();
 443         if (error)
 444                 goto Enable_irqs;
 445
 446         save_processor_state();
 447         error = restore_highmem();
 448         if (!error) {
 449                 error = swsusp_arch_resume();
 450                 /*
 451                  * The code below is only ever reached in case of a failure.
 452                  * Otherwise, execution continues at the place where
 453                  * swsusp_arch_suspend() was called.
 454                  */
 455                 BUG_ON(!error);
 456                 /*
 457                  * This call to restore_highmem() reverts the changes made by
 458                  * the previous one.
 459                  */
 460                 restore_highmem();
 461         }
 462         /*
 463          * The only reason why swsusp_arch_resume() can fail is memory being
 464          * very tight, so we have to free it as soon as we can to avoid
 465          * subsequent failures.
 466          */
 467         swsusp_free();
 468         restore_processor_state();
 469         touch_softlockup_watchdog();
 470
 471         syscore_resume();
 472
 473  Enable_irqs:
 474         local_irq_enable();
 475
 476  Enable_cpus:
 477         enable_nonboot_cpus();
 478
 479  Cleanup:
 480         platform_restore_cleanup(platform_mode);
 481
 482         dpm_resume_start(PMSG_RECOVER);
 483
 484         return error;
 485 }
 486
 487 /**
 488  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 489  * @platform_mode: If set, use platform driver to prepare for the transition.
 490  *
 491  * This routine must be called with pm_mutex held.  If it is successful, control
 492  * reappears in the restored target kernel in hibernation_snapshot().
 493  */
 494 int hibernation_restore(int platform_mode)
 495 {
 496         int error;
 497
 498         pm_prepare_console();
 499         suspend_console();
 500         pm_restrict_gfp_mask();
 501         error = dpm_suspend_start(PMSG_QUIESCE);
 502         if (!error) {
 503                 error = resume_target_kernel(platform_mode);
 504                 /*
 505                  * The above should either succeed and jump to the new kernel,
 506                  * or return with an error. Otherwise things are just
 507                  * undefined, so let's be paranoid.
 508                  */
 509                 BUG_ON(!error);
 510         }
 511         dpm_resume_end(PMSG_RECOVER);
 512         pm_restore_gfp_mask();
 513         resume_console();
 514         pm_restore_console();
 515         return error;
 516 }
 517
 518 /**
 519  * hibernation_platform_enter - Power off the system using the platform driver.
 520  */
 521 int hibernation_platform_enter(void)
 522 {
 523         int error;
 524
 525         if (!hibernation_ops)
 526                 return -ENOSYS;
 527
 528         /*
 529          * We have cancelled the power transition by running
 530          * hibernation_ops->finish() before saving the image, so we should let
 531          * the firmware know that we're going to enter the sleep state after all
 532          */
 533         error = hibernation_ops->begin();
 534         if (error)
 535                 goto Close;
 536
 537         entering_platform_hibernation = true;
 538         suspend_console();
 539         error = dpm_suspend_start(PMSG_HIBERNATE);
 540         if (error) {
 541                 if (hibernation_ops->recover)
 542                         hibernation_ops->recover();
 543                 goto Resume_devices;
 544         }
 545
 546         error = dpm_suspend_end(PMSG_HIBERNATE);
 547         if (error)
 548                 goto Resume_devices;
 549
 550         error = hibernation_ops->prepare();
 551         if (error)
 552                 goto Platform_finish;
 553
 554         error = disable_nonboot_cpus();
 555         if (error)
 556                 goto Enable_cpus;
 557
 558         local_irq_disable();
 559         syscore_suspend();
 560         if (pm_wakeup_pending()) {
 561                 error = -EAGAIN;
 562                 goto Power_up;
 563         }
 564
 565         hibernation_ops->enter();
 566         /* We should never get here */
 567         while (1);
 568
 569  Power_up:
 570         syscore_resume();
 571         local_irq_enable();
 572
 573  Enable_cpus:
 574         enable_nonboot_cpus();
 575
 576  Platform_finish:
 577         hibernation_ops->finish();
 578
 579         dpm_resume_start(PMSG_RESTORE);
 580
 581  Resume_devices:
 582         entering_platform_hibernation = false;
 583         dpm_resume_end(PMSG_RESTORE);
 584         resume_console();
 585
 586  Close:
 587         hibernation_ops->end();
 588
 589         return error;
 590 }
 591
 592 /**
 593  * power_down - Shut the machine down for hibernation.
 594  *
 595  * Use the platform driver, if configured, to put the system into the sleep
 596  * state corresponding to hibernation, or try to power it off or reboot,
 597  * depending on the value of hibernation_mode.
 598  */
 599 static void power_down(void)
 600 {
 601 #ifdef CONFIG_SUSPEND
 602         int error;
 603 #endif
 604
 605         switch (hibernation_mode) {
 606         case HIBERNATION_REBOOT:
 607                 kernel_restart(NULL);
 608                 break;
 609         case HIBERNATION_PLATFORM:
 610                 hibernation_platform_enter();
 611         case HIBERNATION_SHUTDOWN:
 612                 if (pm_power_off)
 613                         kernel_power_off();
 614                 break;
 615 #ifdef CONFIG_SUSPEND
 616         case HIBERNATION_SUSPEND:
 617                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 618                 if (error) {
 619                         if (hibernation_ops)
 620                                 hibernation_mode = HIBERNATION_PLATFORM;
 621                         else
 622                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 623                         power_down();
 624                 }
 625                 /*
 626                  * Restore swap signature.
 627                  */
 628                 error = swsusp_unmark();
 629                 if (error)
 630                         printk(KERN_ERR "PM: Swap will be unusable! "
 631                                         "Try swapon -a.\n");
 632                 return;
 633 #endif
 634         }
 635         kernel_halt();
 636         /*
 637          * Valid image is on the disk, if we continue we risk serious data
 638          * corruption after resume.
 639          */
 640         printk(KERN_CRIT "PM: Please power down manually\n");
 641         while (1)
 642                 cpu_relax();
 643 }
 644
 645 /**
 646  * hibernate - Carry out system hibernation, including saving the image.
 647  */
 648 int hibernate(void)
 649 {
 650         int error;
 651
 652         if (!hibernation_available()) {
 653                 pr_debug("PM: Hibernation not available.\n");
 654                 return -EPERM;
 655         }
 656
 657         lock_system_sleep();
 658         /* The snapshot device should not be opened while we're running */
 659         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 660                 error = -EBUSY;
 661                 goto Unlock;
 662         }
 663
 664         pm_prepare_console();
 665         error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 666         if (error)
 667                 goto Exit;
 668
 669         printk(KERN_INFO "PM: Syncing filesystems ... ");
 670         sys_sync();
 671         printk("done.\n");
 672
 673         error = freeze_processes();
 674         if (error)
 675                 goto Exit;
 676
 677         lock_device_hotplug();
 678         /* Allocate memory management structures */
 679         error = create_basic_memory_bitmaps();
 680         if (error)
 681                 goto Thaw;
 682
 683         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 684         if (error || freezer_test_done)
 685                 goto Free_bitmaps;
 686
 687         if (in_suspend) {
 688                 unsigned int flags = 0;
 689
 690                 if (hibernation_mode == HIBERNATION_PLATFORM)
 691                         flags |= SF_PLATFORM_MODE;
 692                 if (nocompress)
 693                         flags |= SF_NOCOMPRESS_MODE;
 694                 else
 695                         flags |= SF_CRC32_MODE;
 696
 697                 pr_debug("PM: writing image.\n");
 698                 error = swsusp_write(flags);
 699                 swsusp_free();
 700                 if (!error)
 701                         power_down();
 702                 in_suspend = 0;
 703                 pm_restore_gfp_mask();
 704         } else {
 705                 pr_debug("PM: Image restored successfully.\n");
 706         }
 707
 708  Free_bitmaps:
 709         free_basic_memory_bitmaps();
 710  Thaw:
 711         unlock_device_hotplug();
 712         thaw_processes();
 713
 714         /* Don't bother checking whether freezer_test_done is true */
 715         freezer_test_done = false;
 716  Exit:
 717         pm_notifier_call_chain(PM_POST_HIBERNATION);
 718         pm_restore_console();
 719         atomic_inc(&snapshot_device_available);
 720  Unlock:
 721         unlock_system_sleep();
 722         return error;
 723 }
 724
 725
 726 /**
 727  * software_resume - Resume from a saved hibernation image.
 728  *
 729  * This routine is called as a late initcall, when all devices have been
 730  * discovered and initialized already.
 731  *
 732  * The image reading code is called to see if there is a hibernation image
 733  * available for reading.  If that is the case, devices are quiesced and the
 734  * contents of memory is restored from the saved image.
 735  *
 736  * If this is successful, control reappears in the restored target kernel in
 737  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 738  * attempts to recover gracefully and make the kernel return to the normal mode
 739  * of operation.
 740  */
 741 static int software_resume(void)
 742 {
 743         int error;
 744         unsigned int flags;
 745
 746         /*
 747          * If the user said "noresume".. bail out early.
 748          */
 749         if (noresume || !hibernation_available())
 750                 return 0;
 751
 752         /*
 753          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 754          * is configured into the kernel. Since the regular hibernate
 755          * trigger path is via sysfs which takes a buffer mutex before
 756          * calling hibernate functions (which take pm_mutex) this can
 757          * cause lockdep to complain about a possible ABBA deadlock
 758          * which cannot happen since we're in the boot code here and
 759          * sysfs can't be invoked yet. Therefore, we use a subclass
 760          * here to avoid lockdep complaining.
 761          */
 762         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 763
 764         if (swsusp_resume_device)
 765                 goto Check_image;
 766
 767         if (!strlen(resume_file)) {
 768                 error = -ENOENT;
 769                 goto Unlock;
 770         }
 771
 772         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 773
 774         if (resume_delay) {
 775                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 776                         resume_delay);
 777                 ssleep(resume_delay);
 778         }
 779
 780         /* Check if the device is there */
 781         swsusp_resume_device = name_to_dev_t(resume_file);
 782         if (!swsusp_resume_device) {
 783                 /*
 784                  * Some device discovery might still be in progress; we need
 785                  * to wait for this to finish.
 786                  */
 787                 wait_for_device_probe();
 788
 789                 if (resume_wait) {
 790                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 791                                 msleep(10);
 792                         async_synchronize_full();
 793                 }
 794
 795                 swsusp_resume_device = name_to_dev_t(resume_file);
 796                 if (!swsusp_resume_device) {
 797                         error = -ENODEV;
 798                         goto Unlock;
 799                 }
 800         }
 801
 802  Check_image:
 803         pr_debug("PM: Hibernation image partition %d:%d present\n",
 804                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 805
 806         pr_debug("PM: Looking for hibernation image.\n");
 807         error = swsusp_check();
 808         if (error)
 809                 goto Unlock;
 810
 811         /* The snapshot device should not be opened while we're running */
 812         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 813                 error = -EBUSY;
 814                 swsusp_close(FMODE_READ);
 815                 goto Unlock;
 816         }
 817
 818         pm_prepare_console();
 819         error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 820         if (error)
 821                 goto Close_Finish;
 822
 823         pr_debug("PM: Preparing processes for restore.\n");
 824         error = freeze_processes();
 825         if (error)
 826                 goto Close_Finish;
 827
 828         pr_debug("PM: Loading hibernation image.\n");
 829
 830         lock_device_hotplug();
 831         error = create_basic_memory_bitmaps();
 832         if (error)
 833                 goto Thaw;
 834
 835         error = swsusp_read(&flags);
 836         swsusp_close(FMODE_READ);
 837         if (!error)
 838                 hibernation_restore(flags & SF_PLATFORM_MODE);
 839
 840         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 841         swsusp_free();
 842         free_basic_memory_bitmaps();
 843  Thaw:
 844         unlock_device_hotplug();
 845         thaw_processes();
 846  Finish:
 847         pm_notifier_call_chain(PM_POST_RESTORE);
 848         pm_restore_console();
 849         atomic_inc(&snapshot_device_available);
 850         /* For success case, the suspend path will release the lock */
 851  Unlock:
 852         mutex_unlock(&pm_mutex);
 853         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 854         return error;
 855  Close_Finish:
 856         swsusp_close(FMODE_READ);
 857         goto Finish;
 858 }
 859
 860 late_initcall_sync(software_resume);
 861
 862
 863 static const char * const hibernation_modes[] = {
 864         [HIBERNATION_PLATFORM]  = "platform",
 865         [HIBERNATION_SHUTDOWN]  = "shutdown",
 866         [HIBERNATION_REBOOT]    = "reboot",
 867 #ifdef CONFIG_SUSPEND
 868         [HIBERNATION_SUSPEND]   = "suspend",
 869 #endif
 870 };
 871
 872 /*
 873  * /sys/power/disk - Control hibernation mode.
 874  *
 875  * Hibernation can be handled in several ways.  There are a few different ways
 876  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 877  * or other hibernation_ops), powering it off or rebooting it (for testing
 878  * mostly).
 879  *
 880  * The sysfs file /sys/power/disk provides an interface for selecting the
 881  * hibernation mode to use.  Reading from this file causes the available modes
 882  * to be printed.  There are 3 modes that can be supported:
 883  *
 884  *      'platform'
 885  *      'shutdown'
 886  *      'reboot'
 887  *
 888  * If a platform hibernation driver is in use, 'platform' will be supported
 889  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 890  * The selected option (i.e. the one corresponding to the current value of
 891  * hibernation_mode) is enclosed by a square bracket.
 892  *
 893  * To select a given hibernation mode it is necessary to write the mode's
 894  * string representation (as returned by reading from /sys/power/disk) back
 895  * into /sys/power/disk.
 896  */
 897
 898 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 899                          char *buf)
 900 {
 901         int i;
 902         char *start = buf;
 903
 904         if (!hibernation_available())
 905                 return sprintf(buf, "[disabled]\n");
 906
 907         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 908                 if (!hibernation_modes[i])
 909                         continue;
 910                 switch (i) {
 911                 case HIBERNATION_SHUTDOWN:
 912                 case HIBERNATION_REBOOT:
 913 #ifdef CONFIG_SUSPEND
 914                 case HIBERNATION_SUSPEND:
 915 #endif
 916                         break;
 917                 case HIBERNATION_PLATFORM:
 918                         if (hibernation_ops)
 919                                 break;
 920                         /* not a valid mode, continue with loop */
 921                         continue;
 922                 }
 923                 if (i == hibernation_mode)
 924                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 925                 else
 926                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 927         }
 928         buf += sprintf(buf, "\n");
 929         return buf-start;
 930 }
 931
 932 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 933                           const char *buf, size_t n)
 934 {
 935         int error = 0;
 936         int i;
 937         int len;
 938         char *p;
 939         int mode = HIBERNATION_INVALID;
 940
 941         if (!hibernation_available())
 942                 return -EPERM;
 943
 944         p = memchr(buf, '\n', n);
 945         len = p ? p - buf : n;
 946
 947         lock_system_sleep();
 948         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 949                 if (len == strlen(hibernation_modes[i])
 950                     && !strncmp(buf, hibernation_modes[i], len)) {
 951                         mode = i;
 952                         break;
 953                 }
 954         }
 955         if (mode != HIBERNATION_INVALID) {
 956                 switch (mode) {
 957                 case HIBERNATION_SHUTDOWN:
 958                 case HIBERNATION_REBOOT:
 959 #ifdef CONFIG_SUSPEND
 960                 case HIBERNATION_SUSPEND:
 961 #endif
 962                         hibernation_mode = mode;
 963                         break;
 964                 case HIBERNATION_PLATFORM:
 965                         if (hibernation_ops)
 966                                 hibernation_mode = mode;
 967                         else
 968                                 error = -EINVAL;
 969                 }
 970         } else
 971                 error = -EINVAL;
 972
 973         if (!error)
 974                 pr_debug("PM: Hibernation mode set to '%s'\n",
 975                          hibernation_modes[mode]);
 976         unlock_system_sleep();
 977         return error ? error : n;
 978 }
 979
 980 power_attr(disk);
 981
 982 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
 983                            char *buf)
 984 {
 985         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 986                        MINOR(swsusp_resume_device));
 987 }
 988
 989 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 990                             const char *buf, size_t n)
 991 {
 992         dev_t res;
 993         int len = n;
 994         char *name;
 995
 996         if (len && buf[len-1] == '\n')
 997                 len--;
 998         name = kstrndup(buf, len, GFP_KERNEL);
 999         if (!name)
1000                 return -ENOMEM;
1001
1002         res = name_to_dev_t(name);
1003         kfree(name);
1004         if (!res)
1005                 return -EINVAL;
1006
1007         lock_system_sleep();
1008         swsusp_resume_device = res;
1009         unlock_system_sleep();
1010         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1011         noresume = 0;
1012         software_resume();
1013         return n;
1014 }
1015
1016 power_attr(resume);
1017
1018 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1019                                char *buf)
1020 {
1021         return sprintf(buf, "%lu\n", image_size);
1022 }
1023
1024 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1025                                 const char *buf, size_t n)
1026 {
1027         unsigned long size;
1028
1029         if (sscanf(buf, "%lu", &size) == 1) {
1030                 image_size = size;
1031                 return n;
1032         }
1033
1034         return -EINVAL;
1035 }
1036
1037 power_attr(image_size);
1038
1039 static ssize_t reserved_size_show(struct kobject *kobj,
1040                                   struct kobj_attribute *attr, char *buf)
1041 {
1042         return sprintf(buf, "%lu\n", reserved_size);
1043 }
1044
1045 static ssize_t reserved_size_store(struct kobject *kobj,
1046                                    struct kobj_attribute *attr,
1047                                    const char *buf, size_t n)
1048 {
1049         unsigned long size;
1050
1051         if (sscanf(buf, "%lu", &size) == 1) {
1052                 reserved_size = size;
1053                 return n;
1054         }
1055
1056         return -EINVAL;
1057 }
1058
1059 power_attr(reserved_size);
1060
1061 static struct attribute * g[] = {
1062         &disk_attr.attr,
1063         &resume_attr.attr,
1064         &image_size_attr.attr,
1065         &reserved_size_attr.attr,
1066         NULL,
1067 };
1068
1069
1070 static struct attribute_group attr_group = {
1071         .attrs = g,
1072 };
1073
1074
1075 static int __init pm_disk_init(void)
1076 {
1077         return sysfs_create_group(power_kobj, &attr_group);
1078 }
1079
1080 core_initcall(pm_disk_init);
1081
1082
1083 static int __init resume_setup(char *str)
1084 {
1085         if (noresume)
1086                 return 1;
1087
1088         strncpy( resume_file, str, 255 );
1089         return 1;
1090 }
1091
1092 static int __init resume_offset_setup(char *str)
1093 {
1094         unsigned long long offset;
1095
1096         if (noresume)
1097                 return 1;
1098
1099         if (sscanf(str, "%llu", &offset) == 1)
1100                 swsusp_resume_block = offset;
1101
1102         return 1;
1103 }
1104
1105 static int __init hibernate_setup(char *str)
1106 {
1107         if (!strncmp(str, "noresume", 8))
1108                 noresume = 1;
1109         else if (!strncmp(str, "nocompress", 10))
1110                 nocompress = 1;
1111         else if (!strncmp(str, "no", 2)) {
1112                 noresume = 1;
1113                 nohibernate = 1;
1114         }
1115         return 1;
1116 }
1117
1118 static int __init noresume_setup(char *str)
1119 {
1120         noresume = 1;
1121         return 1;
1122 }
1123
1124 static int __init resumewait_setup(char *str)
1125 {
1126         resume_wait = 1;
1127         return 1;
1128 }
1129
1130 static int __init resumedelay_setup(char *str)
1131 {
1132         int rc = kstrtouint(str, 0, &resume_delay);
1133
1134         if (rc)
1135                 return rc;
1136         return 1;
1137 }
1138
1139 static int __init nohibernate_setup(char *str)
1140 {
1141         noresume = 1;
1142         nohibernate = 1;
1143         return 1;
1144 }
1145
1146 static int __init kaslr_nohibernate_setup(char *str)
1147 {
1148         return nohibernate_setup(str);
1149 }
1150
1151 __setup("noresume", noresume_setup);
1152 __setup("resume_offset=", resume_offset_setup);
1153 __setup("resume=", resume_setup);
1154 __setup("hibernate=", hibernate_setup);
1155 __setup("resumewait", resumewait_setup);
1156 __setup("resumedelay=", resumedelay_setup);
1157 __setup("nohibernate", nohibernate_setup);
1158 __setup("kaslr", kaslr_nohibernate_setup);