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v5.9
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   4 *
   5 * Copyright (c) 2003 Patrick Mochel
   6 * Copyright (c) 2003 Open Source Development Lab
   7 * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   8 * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   9 * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
  10 */
  11
  12#define pr_fmt(fmt) "PM: hibernation: " fmt
  13
  14#include <linux/export.h>
  15#include <linux/suspend.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/nmi.h>
  25#include <linux/console.h>
  26#include <linux/cpu.h>
  27#include <linux/freezer.h>
  28#include <linux/gfp.h>
  29#include <linux/syscore_ops.h>
  30#include <linux/ctype.h>
  31#include <linux/genhd.h>
  32#include <linux/ktime.h>
  33#include <linux/security.h>
  34#include <trace/events/power.h>
  35
  36#include "power.h"
  37
  38
  39static int nocompress;
  40static int noresume;
  41static int nohibernate;
  42static int resume_wait;
  43static unsigned int resume_delay;
  44static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  45dev_t swsusp_resume_device;
  46sector_t swsusp_resume_block;
  47__visible int in_suspend __nosavedata;
  48
  49enum {
  50	HIBERNATION_INVALID,
  51	HIBERNATION_PLATFORM,
  52	HIBERNATION_SHUTDOWN,
  53	HIBERNATION_REBOOT,
  54#ifdef CONFIG_SUSPEND
  55	HIBERNATION_SUSPEND,
  56#endif
  57	HIBERNATION_TEST_RESUME,
  58	/* keep last */
  59	__HIBERNATION_AFTER_LAST
  60};
  61#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  62#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  63
  64static int hibernation_mode = HIBERNATION_SHUTDOWN;
  65
  66bool freezer_test_done;
  67
  68static const struct platform_hibernation_ops *hibernation_ops;
  69
  70static atomic_t hibernate_atomic = ATOMIC_INIT(1);
  71
  72bool hibernate_acquire(void)
  73{
  74	return atomic_add_unless(&hibernate_atomic, -1, 0);
  75}
  76
  77void hibernate_release(void)
  78{
  79	atomic_inc(&hibernate_atomic);
  80}
  81
  82bool hibernation_available(void)
  83{
  84	return nohibernate == 0 && !security_locked_down(LOCKDOWN_HIBERNATION);
  85}
  86
  87/**
  88 * hibernation_set_ops - Set the global hibernate operations.
  89 * @ops: Hibernation operations to use in subsequent hibernation transitions.
  90 */
  91void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  92{
  93	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  94	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  95	    && ops->restore_cleanup && ops->leave)) {
  96		WARN_ON(1);
  97		return;
  98	}
  99	lock_system_sleep();
 100	hibernation_ops = ops;
 101	if (ops)
 102		hibernation_mode = HIBERNATION_PLATFORM;
 103	else if (hibernation_mode == HIBERNATION_PLATFORM)
 104		hibernation_mode = HIBERNATION_SHUTDOWN;
 105
 106	unlock_system_sleep();
 107}
 108EXPORT_SYMBOL_GPL(hibernation_set_ops);
 109
 110static bool entering_platform_hibernation;
 111
 112bool system_entering_hibernation(void)
 113{
 114	return entering_platform_hibernation;
 115}
 116EXPORT_SYMBOL(system_entering_hibernation);
 117
 118#ifdef CONFIG_PM_DEBUG
 119static void hibernation_debug_sleep(void)
 120{
 121	pr_info("debug: Waiting for 5 seconds.\n");
 122	mdelay(5000);
 123}
 124
 125static int hibernation_test(int level)
 126{
 127	if (pm_test_level == level) {
 128		hibernation_debug_sleep();
 129		return 1;
 130	}
 131	return 0;
 132}
 133#else /* !CONFIG_PM_DEBUG */
 134static int hibernation_test(int level) { return 0; }
 135#endif /* !CONFIG_PM_DEBUG */
 136
 137/**
 138 * platform_begin - Call platform to start hibernation.
 139 * @platform_mode: Whether or not to use the platform driver.
 140 */
 141static int platform_begin(int platform_mode)
 142{
 143	return (platform_mode && hibernation_ops) ?
 144		hibernation_ops->begin(PMSG_FREEZE) : 0;
 145}
 146
 147/**
 148 * platform_end - Call platform to finish transition to the working state.
 149 * @platform_mode: Whether or not to use the platform driver.
 150 */
 151static void platform_end(int platform_mode)
 152{
 153	if (platform_mode && hibernation_ops)
 154		hibernation_ops->end();
 155}
 156
 157/**
 158 * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 159 * @platform_mode: Whether or not to use the platform driver.
 160 *
 161 * Use the platform driver to prepare the system for creating a hibernate image,
 162 * if so configured, and return an error code if that fails.
 163 */
 164
 165static int platform_pre_snapshot(int platform_mode)
 166{
 167	return (platform_mode && hibernation_ops) ?
 168		hibernation_ops->pre_snapshot() : 0;
 169}
 170
 171/**
 172 * platform_leave - Call platform to prepare a transition to the working state.
 173 * @platform_mode: Whether or not to use the platform driver.
 174 *
 175 * Use the platform driver prepare to prepare the machine for switching to the
 176 * normal mode of operation.
 177 *
 178 * This routine is called on one CPU with interrupts disabled.
 179 */
 180static void platform_leave(int platform_mode)
 181{
 182	if (platform_mode && hibernation_ops)
 183		hibernation_ops->leave();
 184}
 185
 186/**
 187 * platform_finish - Call platform to switch the system to the working state.
 188 * @platform_mode: Whether or not to use the platform driver.
 189 *
 190 * Use the platform driver to switch the machine to the normal mode of
 191 * operation.
 192 *
 193 * This routine must be called after platform_prepare().
 194 */
 195static void platform_finish(int platform_mode)
 196{
 197	if (platform_mode && hibernation_ops)
 198		hibernation_ops->finish();
 199}
 200
 201/**
 202 * platform_pre_restore - Prepare for hibernate image restoration.
 203 * @platform_mode: Whether or not to use the platform driver.
 204 *
 205 * Use the platform driver to prepare the system for resume from a hibernation
 206 * image.
 207 *
 208 * If the restore fails after this function has been called,
 209 * platform_restore_cleanup() must be called.
 210 */
 211static int platform_pre_restore(int platform_mode)
 212{
 213	return (platform_mode && hibernation_ops) ?
 214		hibernation_ops->pre_restore() : 0;
 215}
 216
 217/**
 218 * platform_restore_cleanup - Switch to the working state after failing restore.
 219 * @platform_mode: Whether or not to use the platform driver.
 220 *
 221 * Use the platform driver to switch the system to the normal mode of operation
 222 * after a failing restore.
 223 *
 224 * If platform_pre_restore() has been called before the failing restore, this
 225 * function must be called too, regardless of the result of
 226 * platform_pre_restore().
 227 */
 228static void platform_restore_cleanup(int platform_mode)
 229{
 230	if (platform_mode && hibernation_ops)
 231		hibernation_ops->restore_cleanup();
 232}
 233
 234/**
 235 * platform_recover - Recover from a failure to suspend devices.
 236 * @platform_mode: Whether or not to use the platform driver.
 237 */
 238static void platform_recover(int platform_mode)
 239{
 240	if (platform_mode && hibernation_ops && hibernation_ops->recover)
 241		hibernation_ops->recover();
 242}
 243
 244/**
 245 * swsusp_show_speed - Print time elapsed between two events during hibernation.
 246 * @start: Starting event.
 247 * @stop: Final event.
 248 * @nr_pages: Number of memory pages processed between @start and @stop.
 249 * @msg: Additional diagnostic message to print.
 250 */
 251void swsusp_show_speed(ktime_t start, ktime_t stop,
 252		      unsigned nr_pages, char *msg)
 253{
 254	ktime_t diff;
 255	u64 elapsed_centisecs64;
 256	unsigned int centisecs;
 257	unsigned int k;
 258	unsigned int kps;
 259
 260	diff = ktime_sub(stop, start);
 261	elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 262	centisecs = elapsed_centisecs64;
 263	if (centisecs == 0)
 264		centisecs = 1;	/* avoid div-by-zero */
 265	k = nr_pages * (PAGE_SIZE / 1024);
 266	kps = (k * 100) / centisecs;
 267	pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 268		msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 269		(kps % 1000) / 10);
 270}
 271
 272__weak int arch_resume_nosmt(void)
 273{
 274	return 0;
 275}
 276
 277/**
 278 * create_image - Create a hibernation image.
 279 * @platform_mode: Whether or not to use the platform driver.
 280 *
 281 * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 282 * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 283 *
 284 * Control reappears in this routine after the subsequent restore.
 285 */
 286static int create_image(int platform_mode)
 287{
 288	int error;
 289
 290	error = dpm_suspend_end(PMSG_FREEZE);
 291	if (error) {
 292		pr_err("Some devices failed to power down, aborting\n");
 293		return error;
 294	}
 295
 296	error = platform_pre_snapshot(platform_mode);
 297	if (error || hibernation_test(TEST_PLATFORM))
 298		goto Platform_finish;
 299
 300	error = suspend_disable_secondary_cpus();
 301	if (error || hibernation_test(TEST_CPUS))
 302		goto Enable_cpus;
 303
 304	local_irq_disable();
 305
 306	system_state = SYSTEM_SUSPEND;
 307
 308	error = syscore_suspend();
 309	if (error) {
 310		pr_err("Some system devices failed to power down, aborting\n");
 311		goto Enable_irqs;
 312	}
 313
 314	if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 315		goto Power_up;
 316
 317	in_suspend = 1;
 318	save_processor_state();
 319	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 320	error = swsusp_arch_suspend();
 321	/* Restore control flow magically appears here */
 322	restore_processor_state();
 323	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 324	if (error)
 325		pr_err("Error %d creating image\n", error);
 326
 327	if (!in_suspend) {
 328		events_check_enabled = false;
 329		clear_free_pages();
 330	}
 331
 332	platform_leave(platform_mode);
 333
 334 Power_up:
 335	syscore_resume();
 336
 337 Enable_irqs:
 338	system_state = SYSTEM_RUNNING;
 339	local_irq_enable();
 340
 341 Enable_cpus:
 342	suspend_enable_secondary_cpus();
 343
 344	/* Allow architectures to do nosmt-specific post-resume dances */
 345	if (!in_suspend)
 346		error = arch_resume_nosmt();
 347
 348 Platform_finish:
 349	platform_finish(platform_mode);
 350
 351	dpm_resume_start(in_suspend ?
 352		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 353
 354	return error;
 355}
 356
 357/**
 358 * hibernation_snapshot - Quiesce devices and create a hibernation image.
 359 * @platform_mode: If set, use platform driver to prepare for the transition.
 360 *
 361 * This routine must be called with system_transition_mutex held.
 362 */
 363int hibernation_snapshot(int platform_mode)
 364{
 365	pm_message_t msg;
 366	int error;
 367
 368	pm_suspend_clear_flags();
 369	error = platform_begin(platform_mode);
 370	if (error)
 371		goto Close;
 372
 373	/* Preallocate image memory before shutting down devices. */
 374	error = hibernate_preallocate_memory();
 375	if (error)
 376		goto Close;
 377
 378	error = freeze_kernel_threads();
 379	if (error)
 380		goto Cleanup;
 381
 382	if (hibernation_test(TEST_FREEZER)) {
 383
 384		/*
 385		 * Indicate to the caller that we are returning due to a
 386		 * successful freezer test.
 387		 */
 388		freezer_test_done = true;
 389		goto Thaw;
 390	}
 391
 392	error = dpm_prepare(PMSG_FREEZE);
 393	if (error) {
 394		dpm_complete(PMSG_RECOVER);
 395		goto Thaw;
 396	}
 397
 398	suspend_console();
 399	pm_restrict_gfp_mask();
 400
 401	error = dpm_suspend(PMSG_FREEZE);
 402
 403	if (error || hibernation_test(TEST_DEVICES))
 404		platform_recover(platform_mode);
 405	else
 406		error = create_image(platform_mode);
 407
 408	/*
 409	 * In the case that we call create_image() above, the control
 410	 * returns here (1) after the image has been created or the
 411	 * image creation has failed and (2) after a successful restore.
 412	 */
 413
 414	/* We may need to release the preallocated image pages here. */
 415	if (error || !in_suspend)
 416		swsusp_free();
 417
 418	msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 419	dpm_resume(msg);
 420
 421	if (error || !in_suspend)
 422		pm_restore_gfp_mask();
 423
 424	resume_console();
 425	dpm_complete(msg);
 426
 427 Close:
 428	platform_end(platform_mode);
 429	return error;
 430
 431 Thaw:
 432	thaw_kernel_threads();
 433 Cleanup:
 434	swsusp_free();
 435	goto Close;
 436}
 437
 438int __weak hibernate_resume_nonboot_cpu_disable(void)
 439{
 440	return suspend_disable_secondary_cpus();
 441}
 442
 443/**
 444 * resume_target_kernel - Restore system state from a hibernation image.
 445 * @platform_mode: Whether or not to use the platform driver.
 446 *
 447 * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 448 * contents of highmem that have not been restored yet from the image and run
 449 * the low-level code that will restore the remaining contents of memory and
 450 * switch to the just restored target kernel.
 451 */
 452static int resume_target_kernel(bool platform_mode)
 453{
 454	int error;
 455
 456	error = dpm_suspend_end(PMSG_QUIESCE);
 457	if (error) {
 458		pr_err("Some devices failed to power down, aborting resume\n");
 459		return error;
 460	}
 461
 462	error = platform_pre_restore(platform_mode);
 463	if (error)
 464		goto Cleanup;
 465
 466	error = hibernate_resume_nonboot_cpu_disable();
 467	if (error)
 468		goto Enable_cpus;
 469
 470	local_irq_disable();
 471	system_state = SYSTEM_SUSPEND;
 472
 473	error = syscore_suspend();
 474	if (error)
 475		goto Enable_irqs;
 476
 477	save_processor_state();
 478	error = restore_highmem();
 479	if (!error) {
 480		error = swsusp_arch_resume();
 481		/*
 482		 * The code below is only ever reached in case of a failure.
 483		 * Otherwise, execution continues at the place where
 484		 * swsusp_arch_suspend() was called.
 485		 */
 486		BUG_ON(!error);
 487		/*
 488		 * This call to restore_highmem() reverts the changes made by
 489		 * the previous one.
 490		 */
 491		restore_highmem();
 492	}
 493	/*
 494	 * The only reason why swsusp_arch_resume() can fail is memory being
 495	 * very tight, so we have to free it as soon as we can to avoid
 496	 * subsequent failures.
 497	 */
 498	swsusp_free();
 499	restore_processor_state();
 500	touch_softlockup_watchdog();
 501
 502	syscore_resume();
 503
 504 Enable_irqs:
 505	system_state = SYSTEM_RUNNING;
 506	local_irq_enable();
 507
 508 Enable_cpus:
 509	suspend_enable_secondary_cpus();
 510
 511 Cleanup:
 512	platform_restore_cleanup(platform_mode);
 513
 514	dpm_resume_start(PMSG_RECOVER);
 515
 516	return error;
 517}
 518
 519/**
 520 * hibernation_restore - Quiesce devices and restore from a hibernation image.
 521 * @platform_mode: If set, use platform driver to prepare for the transition.
 522 *
 523 * This routine must be called with system_transition_mutex held.  If it is
 524 * successful, control reappears in the restored target kernel in
 525 * hibernation_snapshot().
 526 */
 527int hibernation_restore(int platform_mode)
 528{
 529	int error;
 530
 531	pm_prepare_console();
 532	suspend_console();
 533	pm_restrict_gfp_mask();
 534	error = dpm_suspend_start(PMSG_QUIESCE);
 535	if (!error) {
 536		error = resume_target_kernel(platform_mode);
 537		/*
 538		 * The above should either succeed and jump to the new kernel,
 539		 * or return with an error. Otherwise things are just
 540		 * undefined, so let's be paranoid.
 541		 */
 542		BUG_ON(!error);
 543	}
 544	dpm_resume_end(PMSG_RECOVER);
 545	pm_restore_gfp_mask();
 546	resume_console();
 547	pm_restore_console();
 548	return error;
 549}
 550
 551/**
 552 * hibernation_platform_enter - Power off the system using the platform driver.
 553 */
 554int hibernation_platform_enter(void)
 555{
 556	int error;
 557
 558	if (!hibernation_ops)
 559		return -ENOSYS;
 560
 561	/*
 562	 * We have cancelled the power transition by running
 563	 * hibernation_ops->finish() before saving the image, so we should let
 564	 * the firmware know that we're going to enter the sleep state after all
 565	 */
 566	error = hibernation_ops->begin(PMSG_HIBERNATE);
 567	if (error)
 568		goto Close;
 569
 570	entering_platform_hibernation = true;
 571	suspend_console();
 572	error = dpm_suspend_start(PMSG_HIBERNATE);
 573	if (error) {
 574		if (hibernation_ops->recover)
 575			hibernation_ops->recover();
 576		goto Resume_devices;
 577	}
 578
 579	error = dpm_suspend_end(PMSG_HIBERNATE);
 580	if (error)
 581		goto Resume_devices;
 582
 583	error = hibernation_ops->prepare();
 584	if (error)
 585		goto Platform_finish;
 586
 587	error = suspend_disable_secondary_cpus();
 588	if (error)
 589		goto Enable_cpus;
 590
 591	local_irq_disable();
 592	system_state = SYSTEM_SUSPEND;
 593	syscore_suspend();
 594	if (pm_wakeup_pending()) {
 595		error = -EAGAIN;
 596		goto Power_up;
 597	}
 598
 599	hibernation_ops->enter();
 600	/* We should never get here */
 601	while (1);
 602
 603 Power_up:
 604	syscore_resume();
 605	system_state = SYSTEM_RUNNING;
 606	local_irq_enable();
 607
 608 Enable_cpus:
 609	suspend_enable_secondary_cpus();
 610
 611 Platform_finish:
 612	hibernation_ops->finish();
 613
 614	dpm_resume_start(PMSG_RESTORE);
 615
 616 Resume_devices:
 617	entering_platform_hibernation = false;
 618	dpm_resume_end(PMSG_RESTORE);
 619	resume_console();
 620
 621 Close:
 622	hibernation_ops->end();
 623
 624	return error;
 625}
 626
 627/**
 628 * power_down - Shut the machine down for hibernation.
 629 *
 630 * Use the platform driver, if configured, to put the system into the sleep
 631 * state corresponding to hibernation, or try to power it off or reboot,
 632 * depending on the value of hibernation_mode.
 633 */
 634static void power_down(void)
 635{
 636#ifdef CONFIG_SUSPEND
 637	int error;
 638
 639	if (hibernation_mode == HIBERNATION_SUSPEND) {
 640		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 641		if (error) {
 642			hibernation_mode = hibernation_ops ?
 643						HIBERNATION_PLATFORM :
 644						HIBERNATION_SHUTDOWN;
 645		} else {
 646			/* Restore swap signature. */
 647			error = swsusp_unmark();
 648			if (error)
 649				pr_err("Swap will be unusable! Try swapon -a.\n");
 650
 651			return;
 652		}
 653	}
 654#endif
 655
 656	switch (hibernation_mode) {
 657	case HIBERNATION_REBOOT:
 658		kernel_restart(NULL);
 659		break;
 660	case HIBERNATION_PLATFORM:
 661		hibernation_platform_enter();
 662		fallthrough;
 663	case HIBERNATION_SHUTDOWN:
 664		if (pm_power_off)
 665			kernel_power_off();
 666		break;
 667	}
 668	kernel_halt();
 669	/*
 670	 * Valid image is on the disk, if we continue we risk serious data
 671	 * corruption after resume.
 672	 */
 673	pr_crit("Power down manually\n");
 674	while (1)
 675		cpu_relax();
 676}
 677
 678static int load_image_and_restore(void)
 679{
 680	int error;
 681	unsigned int flags;
 682
 683	pm_pr_dbg("Loading hibernation image.\n");
 684
 685	lock_device_hotplug();
 686	error = create_basic_memory_bitmaps();
 687	if (error)
 688		goto Unlock;
 689
 690	error = swsusp_read(&flags);
 691	swsusp_close(FMODE_READ);
 692	if (!error)
 693		error = hibernation_restore(flags & SF_PLATFORM_MODE);
 694
 695	pr_err("Failed to load image, recovering.\n");
 696	swsusp_free();
 697	free_basic_memory_bitmaps();
 698 Unlock:
 699	unlock_device_hotplug();
 700
 701	return error;
 702}
 703
 704/**
 705 * hibernate - Carry out system hibernation, including saving the image.
 706 */
 707int hibernate(void)
 708{
 709	int error, nr_calls = 0;
 710	bool snapshot_test = false;
 711
 712	if (!hibernation_available()) {
 713		pm_pr_dbg("Hibernation not available.\n");
 714		return -EPERM;
 715	}
 716
 717	lock_system_sleep();
 718	/* The snapshot device should not be opened while we're running */
 719	if (!hibernate_acquire()) {
 720		error = -EBUSY;
 721		goto Unlock;
 722	}
 723
 724	pr_info("hibernation entry\n");
 725	pm_prepare_console();
 726	error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 727	if (error) {
 728		nr_calls--;
 729		goto Exit;
 730	}
 731
 732	ksys_sync_helper();
 733
 734	error = freeze_processes();
 735	if (error)
 736		goto Exit;
 737
 738	lock_device_hotplug();
 739	/* Allocate memory management structures */
 740	error = create_basic_memory_bitmaps();
 741	if (error)
 742		goto Thaw;
 743
 744	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 745	if (error || freezer_test_done)
 746		goto Free_bitmaps;
 747
 748	if (in_suspend) {
 749		unsigned int flags = 0;
 750
 751		if (hibernation_mode == HIBERNATION_PLATFORM)
 752			flags |= SF_PLATFORM_MODE;
 753		if (nocompress)
 754			flags |= SF_NOCOMPRESS_MODE;
 755		else
 756		        flags |= SF_CRC32_MODE;
 757
 758		pm_pr_dbg("Writing hibernation image.\n");
 759		error = swsusp_write(flags);
 760		swsusp_free();
 761		if (!error) {
 762			if (hibernation_mode == HIBERNATION_TEST_RESUME)
 763				snapshot_test = true;
 764			else
 765				power_down();
 766		}
 767		in_suspend = 0;
 768		pm_restore_gfp_mask();
 769	} else {
 770		pm_pr_dbg("Hibernation image restored successfully.\n");
 771	}
 772
 773 Free_bitmaps:
 774	free_basic_memory_bitmaps();
 775 Thaw:
 776	unlock_device_hotplug();
 777	if (snapshot_test) {
 778		pm_pr_dbg("Checking hibernation image\n");
 779		error = swsusp_check();
 780		if (!error)
 781			error = load_image_and_restore();
 782	}
 783	thaw_processes();
 784
 785	/* Don't bother checking whether freezer_test_done is true */
 786	freezer_test_done = false;
 787 Exit:
 788	__pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 789	pm_restore_console();
 790	hibernate_release();
 791 Unlock:
 792	unlock_system_sleep();
 793	pr_info("hibernation exit\n");
 794
 795	return error;
 796}
 797
 798/**
 799 * hibernate_quiet_exec - Execute a function with all devices frozen.
 800 * @func: Function to execute.
 801 * @data: Data pointer to pass to @func.
 802 *
 803 * Return the @func return value or an error code if it cannot be executed.
 804 */
 805int hibernate_quiet_exec(int (*func)(void *data), void *data)
 806{
 807	int error, nr_calls = 0;
 808
 809	lock_system_sleep();
 810
 811	if (!hibernate_acquire()) {
 812		error = -EBUSY;
 813		goto unlock;
 814	}
 815
 816	pm_prepare_console();
 817
 818	error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 819	if (error) {
 820		nr_calls--;
 821		goto exit;
 822	}
 823
 824	error = freeze_processes();
 825	if (error)
 826		goto exit;
 827
 828	lock_device_hotplug();
 829
 830	pm_suspend_clear_flags();
 831
 832	error = platform_begin(true);
 833	if (error)
 834		goto thaw;
 835
 836	error = freeze_kernel_threads();
 837	if (error)
 838		goto thaw;
 839
 840	error = dpm_prepare(PMSG_FREEZE);
 841	if (error)
 842		goto dpm_complete;
 843
 844	suspend_console();
 845
 846	error = dpm_suspend(PMSG_FREEZE);
 847	if (error)
 848		goto dpm_resume;
 849
 850	error = dpm_suspend_end(PMSG_FREEZE);
 851	if (error)
 852		goto dpm_resume;
 853
 854	error = platform_pre_snapshot(true);
 855	if (error)
 856		goto skip;
 857
 858	error = func(data);
 859
 860skip:
 861	platform_finish(true);
 862
 863	dpm_resume_start(PMSG_THAW);
 864
 865dpm_resume:
 866	dpm_resume(PMSG_THAW);
 867
 868	resume_console();
 869
 870dpm_complete:
 871	dpm_complete(PMSG_THAW);
 872
 873	thaw_kernel_threads();
 874
 875thaw:
 876	platform_end(true);
 877
 878	unlock_device_hotplug();
 879
 880	thaw_processes();
 881
 882exit:
 883	__pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 884
 885	pm_restore_console();
 886
 887	hibernate_release();
 888
 889unlock:
 890	unlock_system_sleep();
 891
 892	return error;
 893}
 894EXPORT_SYMBOL_GPL(hibernate_quiet_exec);
 895
 896/**
 897 * software_resume - Resume from a saved hibernation image.
 898 *
 899 * This routine is called as a late initcall, when all devices have been
 900 * discovered and initialized already.
 901 *
 902 * The image reading code is called to see if there is a hibernation image
 903 * available for reading.  If that is the case, devices are quiesced and the
 904 * contents of memory is restored from the saved image.
 905 *
 906 * If this is successful, control reappears in the restored target kernel in
 907 * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 908 * attempts to recover gracefully and make the kernel return to the normal mode
 909 * of operation.
 910 */
 911static int software_resume(void)
 912{
 913	int error, nr_calls = 0;
 914
 915	/*
 916	 * If the user said "noresume".. bail out early.
 917	 */
 918	if (noresume || !hibernation_available())
 919		return 0;
 920
 921	/*
 922	 * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 923	 * is configured into the kernel. Since the regular hibernate
 924	 * trigger path is via sysfs which takes a buffer mutex before
 925	 * calling hibernate functions (which take system_transition_mutex)
 926	 * this can cause lockdep to complain about a possible ABBA deadlock
 927	 * which cannot happen since we're in the boot code here and
 928	 * sysfs can't be invoked yet. Therefore, we use a subclass
 929	 * here to avoid lockdep complaining.
 930	 */
 931	mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 932
 933	if (swsusp_resume_device)
 934		goto Check_image;
 935
 936	if (!strlen(resume_file)) {
 937		error = -ENOENT;
 938		goto Unlock;
 939	}
 940
 941	pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 942
 943	if (resume_delay) {
 944		pr_info("Waiting %dsec before reading resume device ...\n",
 945			resume_delay);
 946		ssleep(resume_delay);
 947	}
 948
 949	/* Check if the device is there */
 950	swsusp_resume_device = name_to_dev_t(resume_file);
 951
 952	/*
 953	 * name_to_dev_t is ineffective to verify parition if resume_file is in
 954	 * integer format. (e.g. major:minor)
 955	 */
 956	if (isdigit(resume_file[0]) && resume_wait) {
 957		int partno;
 958		while (!get_gendisk(swsusp_resume_device, &partno))
 959			msleep(10);
 960	}
 961
 962	if (!swsusp_resume_device) {
 963		/*
 964		 * Some device discovery might still be in progress; we need
 965		 * to wait for this to finish.
 966		 */
 967		wait_for_device_probe();
 968
 969		if (resume_wait) {
 970			while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 971				msleep(10);
 972			async_synchronize_full();
 973		}
 974
 975		swsusp_resume_device = name_to_dev_t(resume_file);
 976		if (!swsusp_resume_device) {
 977			error = -ENODEV;
 978			goto Unlock;
 979		}
 980	}
 981
 982 Check_image:
 983	pm_pr_dbg("Hibernation image partition %d:%d present\n",
 984		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 985
 986	pm_pr_dbg("Looking for hibernation image.\n");
 987	error = swsusp_check();
 988	if (error)
 989		goto Unlock;
 990
 991	/* The snapshot device should not be opened while we're running */
 992	if (!hibernate_acquire()) {
 993		error = -EBUSY;
 994		swsusp_close(FMODE_READ);
 995		goto Unlock;
 996	}
 997
 998	pr_info("resume from hibernation\n");
 999	pm_prepare_console();
1000	error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
1001	if (error) {
1002		nr_calls--;
1003		goto Close_Finish;
1004	}
1005
1006	pm_pr_dbg("Preparing processes for hibernation restore.\n");
1007	error = freeze_processes();
1008	if (error)
1009		goto Close_Finish;
1010
1011	error = freeze_kernel_threads();
1012	if (error) {
1013		thaw_processes();
1014		goto Close_Finish;
1015	}
1016
1017	error = load_image_and_restore();
1018	thaw_processes();
1019 Finish:
1020	__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
1021	pm_restore_console();
1022	pr_info("resume failed (%d)\n", error);
1023	hibernate_release();
1024	/* For success case, the suspend path will release the lock */
1025 Unlock:
1026	mutex_unlock(&system_transition_mutex);
1027	pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
1028	return error;
1029 Close_Finish:
1030	swsusp_close(FMODE_READ);
1031	goto Finish;
1032}
1033
1034late_initcall_sync(software_resume);
1035
1036
1037static const char * const hibernation_modes[] = {
1038	[HIBERNATION_PLATFORM]	= "platform",
1039	[HIBERNATION_SHUTDOWN]	= "shutdown",
1040	[HIBERNATION_REBOOT]	= "reboot",
1041#ifdef CONFIG_SUSPEND
1042	[HIBERNATION_SUSPEND]	= "suspend",
1043#endif
1044	[HIBERNATION_TEST_RESUME]	= "test_resume",
1045};
1046
1047/*
1048 * /sys/power/disk - Control hibernation mode.
1049 *
1050 * Hibernation can be handled in several ways.  There are a few different ways
1051 * to put the system into the sleep state: using the platform driver (e.g. ACPI
1052 * or other hibernation_ops), powering it off or rebooting it (for testing
1053 * mostly).
1054 *
1055 * The sysfs file /sys/power/disk provides an interface for selecting the
1056 * hibernation mode to use.  Reading from this file causes the available modes
1057 * to be printed.  There are 3 modes that can be supported:
1058 *
1059 *	'platform'
1060 *	'shutdown'
1061 *	'reboot'
1062 *
1063 * If a platform hibernation driver is in use, 'platform' will be supported
1064 * and will be used by default.  Otherwise, 'shutdown' will be used by default.
1065 * The selected option (i.e. the one corresponding to the current value of
1066 * hibernation_mode) is enclosed by a square bracket.
1067 *
1068 * To select a given hibernation mode it is necessary to write the mode's
1069 * string representation (as returned by reading from /sys/power/disk) back
1070 * into /sys/power/disk.
1071 */
1072
1073static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
1074			 char *buf)
1075{
1076	int i;
1077	char *start = buf;
1078
1079	if (!hibernation_available())
1080		return sprintf(buf, "[disabled]\n");
1081
1082	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1083		if (!hibernation_modes[i])
1084			continue;
1085		switch (i) {
1086		case HIBERNATION_SHUTDOWN:
1087		case HIBERNATION_REBOOT:
1088#ifdef CONFIG_SUSPEND
1089		case HIBERNATION_SUSPEND:
1090#endif
1091		case HIBERNATION_TEST_RESUME:
1092			break;
1093		case HIBERNATION_PLATFORM:
1094			if (hibernation_ops)
1095				break;
1096			/* not a valid mode, continue with loop */
1097			continue;
1098		}
1099		if (i == hibernation_mode)
1100			buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
1101		else
1102			buf += sprintf(buf, "%s ", hibernation_modes[i]);
1103	}
1104	buf += sprintf(buf, "\n");
1105	return buf-start;
1106}
1107
1108static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
1109			  const char *buf, size_t n)
1110{
1111	int error = 0;
1112	int i;
1113	int len;
1114	char *p;
1115	int mode = HIBERNATION_INVALID;
1116
1117	if (!hibernation_available())
1118		return -EPERM;
1119
1120	p = memchr(buf, '\n', n);
1121	len = p ? p - buf : n;
1122
1123	lock_system_sleep();
1124	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1125		if (len == strlen(hibernation_modes[i])
1126		    && !strncmp(buf, hibernation_modes[i], len)) {
1127			mode = i;
1128			break;
1129		}
1130	}
1131	if (mode != HIBERNATION_INVALID) {
1132		switch (mode) {
1133		case HIBERNATION_SHUTDOWN:
1134		case HIBERNATION_REBOOT:
1135#ifdef CONFIG_SUSPEND
1136		case HIBERNATION_SUSPEND:
1137#endif
1138		case HIBERNATION_TEST_RESUME:
1139			hibernation_mode = mode;
1140			break;
1141		case HIBERNATION_PLATFORM:
1142			if (hibernation_ops)
1143				hibernation_mode = mode;
1144			else
1145				error = -EINVAL;
1146		}
1147	} else
1148		error = -EINVAL;
1149
1150	if (!error)
1151		pm_pr_dbg("Hibernation mode set to '%s'\n",
1152			       hibernation_modes[mode]);
1153	unlock_system_sleep();
1154	return error ? error : n;
1155}
1156
1157power_attr(disk);
1158
1159static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1160			   char *buf)
1161{
1162	return sprintf(buf, "%d:%d\n", MAJOR(swsusp_resume_device),
1163		       MINOR(swsusp_resume_device));
1164}
1165
1166static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1167			    const char *buf, size_t n)
1168{
1169	dev_t res;
1170	int len = n;
1171	char *name;
1172
1173	if (len && buf[len-1] == '\n')
1174		len--;
1175	name = kstrndup(buf, len, GFP_KERNEL);
1176	if (!name)
1177		return -ENOMEM;
1178
1179	res = name_to_dev_t(name);
1180	kfree(name);
1181	if (!res)
1182		return -EINVAL;
1183
1184	lock_system_sleep();
1185	swsusp_resume_device = res;
1186	unlock_system_sleep();
1187	pm_pr_dbg("Configured hibernation resume from disk to %u\n",
1188		  swsusp_resume_device);
1189	noresume = 0;
1190	software_resume();
1191	return n;
1192}
1193
1194power_attr(resume);
1195
1196static ssize_t resume_offset_show(struct kobject *kobj,
1197				  struct kobj_attribute *attr, char *buf)
1198{
1199	return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1200}
1201
1202static ssize_t resume_offset_store(struct kobject *kobj,
1203				   struct kobj_attribute *attr, const char *buf,
1204				   size_t n)
1205{
1206	unsigned long long offset;
1207	int rc;
1208
1209	rc = kstrtoull(buf, 0, &offset);
1210	if (rc)
1211		return rc;
1212	swsusp_resume_block = offset;
1213
1214	return n;
1215}
1216
1217power_attr(resume_offset);
1218
1219static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1220			       char *buf)
1221{
1222	return sprintf(buf, "%lu\n", image_size);
1223}
1224
1225static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1226				const char *buf, size_t n)
1227{
1228	unsigned long size;
1229
1230	if (sscanf(buf, "%lu", &size) == 1) {
1231		image_size = size;
1232		return n;
1233	}
1234
1235	return -EINVAL;
1236}
1237
1238power_attr(image_size);
1239
1240static ssize_t reserved_size_show(struct kobject *kobj,
1241				  struct kobj_attribute *attr, char *buf)
1242{
1243	return sprintf(buf, "%lu\n", reserved_size);
1244}
1245
1246static ssize_t reserved_size_store(struct kobject *kobj,
1247				   struct kobj_attribute *attr,
1248				   const char *buf, size_t n)
1249{
1250	unsigned long size;
1251
1252	if (sscanf(buf, "%lu", &size) == 1) {
1253		reserved_size = size;
1254		return n;
1255	}
1256
1257	return -EINVAL;
1258}
1259
1260power_attr(reserved_size);
1261
1262static struct attribute *g[] = {
1263	&disk_attr.attr,
1264	&resume_offset_attr.attr,
1265	&resume_attr.attr,
1266	&image_size_attr.attr,
1267	&reserved_size_attr.attr,
1268	NULL,
1269};
1270
1271
1272static const struct attribute_group attr_group = {
1273	.attrs = g,
1274};
1275
1276
1277static int __init pm_disk_init(void)
1278{
1279	return sysfs_create_group(power_kobj, &attr_group);
1280}
1281
1282core_initcall(pm_disk_init);
1283
1284
1285static int __init resume_setup(char *str)
1286{
1287	if (noresume)
1288		return 1;
1289
1290	strncpy(resume_file, str, 255);
1291	return 1;
1292}
1293
1294static int __init resume_offset_setup(char *str)
1295{
1296	unsigned long long offset;
1297
1298	if (noresume)
1299		return 1;
1300
1301	if (sscanf(str, "%llu", &offset) == 1)
1302		swsusp_resume_block = offset;
1303
1304	return 1;
1305}
1306
1307static int __init hibernate_setup(char *str)
1308{
1309	if (!strncmp(str, "noresume", 8)) {
1310		noresume = 1;
1311	} else if (!strncmp(str, "nocompress", 10)) {
1312		nocompress = 1;
1313	} else if (!strncmp(str, "no", 2)) {
1314		noresume = 1;
1315		nohibernate = 1;
1316	} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1317		   && !strncmp(str, "protect_image", 13)) {
1318		enable_restore_image_protection();
1319	}
1320	return 1;
1321}
1322
1323static int __init noresume_setup(char *str)
1324{
1325	noresume = 1;
1326	return 1;
1327}
1328
1329static int __init resumewait_setup(char *str)
1330{
1331	resume_wait = 1;
1332	return 1;
1333}
1334
1335static int __init resumedelay_setup(char *str)
1336{
1337	int rc = kstrtouint(str, 0, &resume_delay);
1338
1339	if (rc)
1340		return rc;
1341	return 1;
1342}
1343
1344static int __init nohibernate_setup(char *str)
1345{
1346	noresume = 1;
1347	nohibernate = 1;
1348	return 1;
1349}
1350
1351__setup("noresume", noresume_setup);
1352__setup("resume_offset=", resume_offset_setup);
1353__setup("resume=", resume_setup);
1354__setup("hibernate=", hibernate_setup);
1355__setup("resumewait", resumewait_setup);
1356__setup("resumedelay=", resumedelay_setup);
1357__setup("nohibernate", nohibernate_setup);
v5.4
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   4 *
   5 * Copyright (c) 2003 Patrick Mochel
   6 * Copyright (c) 2003 Open Source Development Lab
   7 * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   8 * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   9 * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
  10 */
  11
  12#define pr_fmt(fmt) "PM: " fmt
  13
  14#include <linux/export.h>
  15#include <linux/suspend.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/nmi.h>
  25#include <linux/console.h>
  26#include <linux/cpu.h>
  27#include <linux/freezer.h>
  28#include <linux/gfp.h>
  29#include <linux/syscore_ops.h>
  30#include <linux/ctype.h>
  31#include <linux/genhd.h>
  32#include <linux/ktime.h>
  33#include <linux/security.h>
  34#include <trace/events/power.h>
  35
  36#include "power.h"
  37
  38
  39static int nocompress;
  40static int noresume;
  41static int nohibernate;
  42static int resume_wait;
  43static unsigned int resume_delay;
  44static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  45dev_t swsusp_resume_device;
  46sector_t swsusp_resume_block;
  47__visible int in_suspend __nosavedata;
  48
  49enum {
  50	HIBERNATION_INVALID,
  51	HIBERNATION_PLATFORM,
  52	HIBERNATION_SHUTDOWN,
  53	HIBERNATION_REBOOT,
  54#ifdef CONFIG_SUSPEND
  55	HIBERNATION_SUSPEND,
  56#endif
  57	HIBERNATION_TEST_RESUME,
  58	/* keep last */
  59	__HIBERNATION_AFTER_LAST
  60};
  61#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  62#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  63
  64static int hibernation_mode = HIBERNATION_SHUTDOWN;
  65
  66bool freezer_test_done;
  67
  68static const struct platform_hibernation_ops *hibernation_ops;
  69
 
 
 
 
 
 
 
 
 
 
 
 
  70bool hibernation_available(void)
  71{
  72	return nohibernate == 0 && !security_locked_down(LOCKDOWN_HIBERNATION);
  73}
  74
  75/**
  76 * hibernation_set_ops - Set the global hibernate operations.
  77 * @ops: Hibernation operations to use in subsequent hibernation transitions.
  78 */
  79void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  80{
  81	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  82	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  83	    && ops->restore_cleanup && ops->leave)) {
  84		WARN_ON(1);
  85		return;
  86	}
  87	lock_system_sleep();
  88	hibernation_ops = ops;
  89	if (ops)
  90		hibernation_mode = HIBERNATION_PLATFORM;
  91	else if (hibernation_mode == HIBERNATION_PLATFORM)
  92		hibernation_mode = HIBERNATION_SHUTDOWN;
  93
  94	unlock_system_sleep();
  95}
  96EXPORT_SYMBOL_GPL(hibernation_set_ops);
  97
  98static bool entering_platform_hibernation;
  99
 100bool system_entering_hibernation(void)
 101{
 102	return entering_platform_hibernation;
 103}
 104EXPORT_SYMBOL(system_entering_hibernation);
 105
 106#ifdef CONFIG_PM_DEBUG
 107static void hibernation_debug_sleep(void)
 108{
 109	pr_info("hibernation debug: Waiting for 5 seconds.\n");
 110	mdelay(5000);
 111}
 112
 113static int hibernation_test(int level)
 114{
 115	if (pm_test_level == level) {
 116		hibernation_debug_sleep();
 117		return 1;
 118	}
 119	return 0;
 120}
 121#else /* !CONFIG_PM_DEBUG */
 122static int hibernation_test(int level) { return 0; }
 123#endif /* !CONFIG_PM_DEBUG */
 124
 125/**
 126 * platform_begin - Call platform to start hibernation.
 127 * @platform_mode: Whether or not to use the platform driver.
 128 */
 129static int platform_begin(int platform_mode)
 130{
 131	return (platform_mode && hibernation_ops) ?
 132		hibernation_ops->begin(PMSG_FREEZE) : 0;
 133}
 134
 135/**
 136 * platform_end - Call platform to finish transition to the working state.
 137 * @platform_mode: Whether or not to use the platform driver.
 138 */
 139static void platform_end(int platform_mode)
 140{
 141	if (platform_mode && hibernation_ops)
 142		hibernation_ops->end();
 143}
 144
 145/**
 146 * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 147 * @platform_mode: Whether or not to use the platform driver.
 148 *
 149 * Use the platform driver to prepare the system for creating a hibernate image,
 150 * if so configured, and return an error code if that fails.
 151 */
 152
 153static int platform_pre_snapshot(int platform_mode)
 154{
 155	return (platform_mode && hibernation_ops) ?
 156		hibernation_ops->pre_snapshot() : 0;
 157}
 158
 159/**
 160 * platform_leave - Call platform to prepare a transition to the working state.
 161 * @platform_mode: Whether or not to use the platform driver.
 162 *
 163 * Use the platform driver prepare to prepare the machine for switching to the
 164 * normal mode of operation.
 165 *
 166 * This routine is called on one CPU with interrupts disabled.
 167 */
 168static void platform_leave(int platform_mode)
 169{
 170	if (platform_mode && hibernation_ops)
 171		hibernation_ops->leave();
 172}
 173
 174/**
 175 * platform_finish - Call platform to switch the system to the working state.
 176 * @platform_mode: Whether or not to use the platform driver.
 177 *
 178 * Use the platform driver to switch the machine to the normal mode of
 179 * operation.
 180 *
 181 * This routine must be called after platform_prepare().
 182 */
 183static void platform_finish(int platform_mode)
 184{
 185	if (platform_mode && hibernation_ops)
 186		hibernation_ops->finish();
 187}
 188
 189/**
 190 * platform_pre_restore - Prepare for hibernate image restoration.
 191 * @platform_mode: Whether or not to use the platform driver.
 192 *
 193 * Use the platform driver to prepare the system for resume from a hibernation
 194 * image.
 195 *
 196 * If the restore fails after this function has been called,
 197 * platform_restore_cleanup() must be called.
 198 */
 199static int platform_pre_restore(int platform_mode)
 200{
 201	return (platform_mode && hibernation_ops) ?
 202		hibernation_ops->pre_restore() : 0;
 203}
 204
 205/**
 206 * platform_restore_cleanup - Switch to the working state after failing restore.
 207 * @platform_mode: Whether or not to use the platform driver.
 208 *
 209 * Use the platform driver to switch the system to the normal mode of operation
 210 * after a failing restore.
 211 *
 212 * If platform_pre_restore() has been called before the failing restore, this
 213 * function must be called too, regardless of the result of
 214 * platform_pre_restore().
 215 */
 216static void platform_restore_cleanup(int platform_mode)
 217{
 218	if (platform_mode && hibernation_ops)
 219		hibernation_ops->restore_cleanup();
 220}
 221
 222/**
 223 * platform_recover - Recover from a failure to suspend devices.
 224 * @platform_mode: Whether or not to use the platform driver.
 225 */
 226static void platform_recover(int platform_mode)
 227{
 228	if (platform_mode && hibernation_ops && hibernation_ops->recover)
 229		hibernation_ops->recover();
 230}
 231
 232/**
 233 * swsusp_show_speed - Print time elapsed between two events during hibernation.
 234 * @start: Starting event.
 235 * @stop: Final event.
 236 * @nr_pages: Number of memory pages processed between @start and @stop.
 237 * @msg: Additional diagnostic message to print.
 238 */
 239void swsusp_show_speed(ktime_t start, ktime_t stop,
 240		      unsigned nr_pages, char *msg)
 241{
 242	ktime_t diff;
 243	u64 elapsed_centisecs64;
 244	unsigned int centisecs;
 245	unsigned int k;
 246	unsigned int kps;
 247
 248	diff = ktime_sub(stop, start);
 249	elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 250	centisecs = elapsed_centisecs64;
 251	if (centisecs == 0)
 252		centisecs = 1;	/* avoid div-by-zero */
 253	k = nr_pages * (PAGE_SIZE / 1024);
 254	kps = (k * 100) / centisecs;
 255	pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 256		msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 257		(kps % 1000) / 10);
 258}
 259
 260__weak int arch_resume_nosmt(void)
 261{
 262	return 0;
 263}
 264
 265/**
 266 * create_image - Create a hibernation image.
 267 * @platform_mode: Whether or not to use the platform driver.
 268 *
 269 * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 270 * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 271 *
 272 * Control reappears in this routine after the subsequent restore.
 273 */
 274static int create_image(int platform_mode)
 275{
 276	int error;
 277
 278	error = dpm_suspend_end(PMSG_FREEZE);
 279	if (error) {
 280		pr_err("Some devices failed to power down, aborting hibernation\n");
 281		return error;
 282	}
 283
 284	error = platform_pre_snapshot(platform_mode);
 285	if (error || hibernation_test(TEST_PLATFORM))
 286		goto Platform_finish;
 287
 288	error = suspend_disable_secondary_cpus();
 289	if (error || hibernation_test(TEST_CPUS))
 290		goto Enable_cpus;
 291
 292	local_irq_disable();
 293
 294	system_state = SYSTEM_SUSPEND;
 295
 296	error = syscore_suspend();
 297	if (error) {
 298		pr_err("Some system devices failed to power down, aborting hibernation\n");
 299		goto Enable_irqs;
 300	}
 301
 302	if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 303		goto Power_up;
 304
 305	in_suspend = 1;
 306	save_processor_state();
 307	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 308	error = swsusp_arch_suspend();
 309	/* Restore control flow magically appears here */
 310	restore_processor_state();
 311	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 312	if (error)
 313		pr_err("Error %d creating hibernation image\n", error);
 314
 315	if (!in_suspend) {
 316		events_check_enabled = false;
 317		clear_free_pages();
 318	}
 319
 320	platform_leave(platform_mode);
 321
 322 Power_up:
 323	syscore_resume();
 324
 325 Enable_irqs:
 326	system_state = SYSTEM_RUNNING;
 327	local_irq_enable();
 328
 329 Enable_cpus:
 330	suspend_enable_secondary_cpus();
 331
 332	/* Allow architectures to do nosmt-specific post-resume dances */
 333	if (!in_suspend)
 334		error = arch_resume_nosmt();
 335
 336 Platform_finish:
 337	platform_finish(platform_mode);
 338
 339	dpm_resume_start(in_suspend ?
 340		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 341
 342	return error;
 343}
 344
 345/**
 346 * hibernation_snapshot - Quiesce devices and create a hibernation image.
 347 * @platform_mode: If set, use platform driver to prepare for the transition.
 348 *
 349 * This routine must be called with system_transition_mutex held.
 350 */
 351int hibernation_snapshot(int platform_mode)
 352{
 353	pm_message_t msg;
 354	int error;
 355
 356	pm_suspend_clear_flags();
 357	error = platform_begin(platform_mode);
 358	if (error)
 359		goto Close;
 360
 361	/* Preallocate image memory before shutting down devices. */
 362	error = hibernate_preallocate_memory();
 363	if (error)
 364		goto Close;
 365
 366	error = freeze_kernel_threads();
 367	if (error)
 368		goto Cleanup;
 369
 370	if (hibernation_test(TEST_FREEZER)) {
 371
 372		/*
 373		 * Indicate to the caller that we are returning due to a
 374		 * successful freezer test.
 375		 */
 376		freezer_test_done = true;
 377		goto Thaw;
 378	}
 379
 380	error = dpm_prepare(PMSG_FREEZE);
 381	if (error) {
 382		dpm_complete(PMSG_RECOVER);
 383		goto Thaw;
 384	}
 385
 386	suspend_console();
 387	pm_restrict_gfp_mask();
 388
 389	error = dpm_suspend(PMSG_FREEZE);
 390
 391	if (error || hibernation_test(TEST_DEVICES))
 392		platform_recover(platform_mode);
 393	else
 394		error = create_image(platform_mode);
 395
 396	/*
 397	 * In the case that we call create_image() above, the control
 398	 * returns here (1) after the image has been created or the
 399	 * image creation has failed and (2) after a successful restore.
 400	 */
 401
 402	/* We may need to release the preallocated image pages here. */
 403	if (error || !in_suspend)
 404		swsusp_free();
 405
 406	msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 407	dpm_resume(msg);
 408
 409	if (error || !in_suspend)
 410		pm_restore_gfp_mask();
 411
 412	resume_console();
 413	dpm_complete(msg);
 414
 415 Close:
 416	platform_end(platform_mode);
 417	return error;
 418
 419 Thaw:
 420	thaw_kernel_threads();
 421 Cleanup:
 422	swsusp_free();
 423	goto Close;
 424}
 425
 426int __weak hibernate_resume_nonboot_cpu_disable(void)
 427{
 428	return suspend_disable_secondary_cpus();
 429}
 430
 431/**
 432 * resume_target_kernel - Restore system state from a hibernation image.
 433 * @platform_mode: Whether or not to use the platform driver.
 434 *
 435 * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 436 * contents of highmem that have not been restored yet from the image and run
 437 * the low-level code that will restore the remaining contents of memory and
 438 * switch to the just restored target kernel.
 439 */
 440static int resume_target_kernel(bool platform_mode)
 441{
 442	int error;
 443
 444	error = dpm_suspend_end(PMSG_QUIESCE);
 445	if (error) {
 446		pr_err("Some devices failed to power down, aborting resume\n");
 447		return error;
 448	}
 449
 450	error = platform_pre_restore(platform_mode);
 451	if (error)
 452		goto Cleanup;
 453
 454	error = hibernate_resume_nonboot_cpu_disable();
 455	if (error)
 456		goto Enable_cpus;
 457
 458	local_irq_disable();
 459	system_state = SYSTEM_SUSPEND;
 460
 461	error = syscore_suspend();
 462	if (error)
 463		goto Enable_irqs;
 464
 465	save_processor_state();
 466	error = restore_highmem();
 467	if (!error) {
 468		error = swsusp_arch_resume();
 469		/*
 470		 * The code below is only ever reached in case of a failure.
 471		 * Otherwise, execution continues at the place where
 472		 * swsusp_arch_suspend() was called.
 473		 */
 474		BUG_ON(!error);
 475		/*
 476		 * This call to restore_highmem() reverts the changes made by
 477		 * the previous one.
 478		 */
 479		restore_highmem();
 480	}
 481	/*
 482	 * The only reason why swsusp_arch_resume() can fail is memory being
 483	 * very tight, so we have to free it as soon as we can to avoid
 484	 * subsequent failures.
 485	 */
 486	swsusp_free();
 487	restore_processor_state();
 488	touch_softlockup_watchdog();
 489
 490	syscore_resume();
 491
 492 Enable_irqs:
 493	system_state = SYSTEM_RUNNING;
 494	local_irq_enable();
 495
 496 Enable_cpus:
 497	suspend_enable_secondary_cpus();
 498
 499 Cleanup:
 500	platform_restore_cleanup(platform_mode);
 501
 502	dpm_resume_start(PMSG_RECOVER);
 503
 504	return error;
 505}
 506
 507/**
 508 * hibernation_restore - Quiesce devices and restore from a hibernation image.
 509 * @platform_mode: If set, use platform driver to prepare for the transition.
 510 *
 511 * This routine must be called with system_transition_mutex held.  If it is
 512 * successful, control reappears in the restored target kernel in
 513 * hibernation_snapshot().
 514 */
 515int hibernation_restore(int platform_mode)
 516{
 517	int error;
 518
 519	pm_prepare_console();
 520	suspend_console();
 521	pm_restrict_gfp_mask();
 522	error = dpm_suspend_start(PMSG_QUIESCE);
 523	if (!error) {
 524		error = resume_target_kernel(platform_mode);
 525		/*
 526		 * The above should either succeed and jump to the new kernel,
 527		 * or return with an error. Otherwise things are just
 528		 * undefined, so let's be paranoid.
 529		 */
 530		BUG_ON(!error);
 531	}
 532	dpm_resume_end(PMSG_RECOVER);
 533	pm_restore_gfp_mask();
 534	resume_console();
 535	pm_restore_console();
 536	return error;
 537}
 538
 539/**
 540 * hibernation_platform_enter - Power off the system using the platform driver.
 541 */
 542int hibernation_platform_enter(void)
 543{
 544	int error;
 545
 546	if (!hibernation_ops)
 547		return -ENOSYS;
 548
 549	/*
 550	 * We have cancelled the power transition by running
 551	 * hibernation_ops->finish() before saving the image, so we should let
 552	 * the firmware know that we're going to enter the sleep state after all
 553	 */
 554	error = hibernation_ops->begin(PMSG_HIBERNATE);
 555	if (error)
 556		goto Close;
 557
 558	entering_platform_hibernation = true;
 559	suspend_console();
 560	error = dpm_suspend_start(PMSG_HIBERNATE);
 561	if (error) {
 562		if (hibernation_ops->recover)
 563			hibernation_ops->recover();
 564		goto Resume_devices;
 565	}
 566
 567	error = dpm_suspend_end(PMSG_HIBERNATE);
 568	if (error)
 569		goto Resume_devices;
 570
 571	error = hibernation_ops->prepare();
 572	if (error)
 573		goto Platform_finish;
 574
 575	error = suspend_disable_secondary_cpus();
 576	if (error)
 577		goto Enable_cpus;
 578
 579	local_irq_disable();
 580	system_state = SYSTEM_SUSPEND;
 581	syscore_suspend();
 582	if (pm_wakeup_pending()) {
 583		error = -EAGAIN;
 584		goto Power_up;
 585	}
 586
 587	hibernation_ops->enter();
 588	/* We should never get here */
 589	while (1);
 590
 591 Power_up:
 592	syscore_resume();
 593	system_state = SYSTEM_RUNNING;
 594	local_irq_enable();
 595
 596 Enable_cpus:
 597	suspend_enable_secondary_cpus();
 598
 599 Platform_finish:
 600	hibernation_ops->finish();
 601
 602	dpm_resume_start(PMSG_RESTORE);
 603
 604 Resume_devices:
 605	entering_platform_hibernation = false;
 606	dpm_resume_end(PMSG_RESTORE);
 607	resume_console();
 608
 609 Close:
 610	hibernation_ops->end();
 611
 612	return error;
 613}
 614
 615/**
 616 * power_down - Shut the machine down for hibernation.
 617 *
 618 * Use the platform driver, if configured, to put the system into the sleep
 619 * state corresponding to hibernation, or try to power it off or reboot,
 620 * depending on the value of hibernation_mode.
 621 */
 622static void power_down(void)
 623{
 624#ifdef CONFIG_SUSPEND
 625	int error;
 626
 627	if (hibernation_mode == HIBERNATION_SUSPEND) {
 628		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 629		if (error) {
 630			hibernation_mode = hibernation_ops ?
 631						HIBERNATION_PLATFORM :
 632						HIBERNATION_SHUTDOWN;
 633		} else {
 634			/* Restore swap signature. */
 635			error = swsusp_unmark();
 636			if (error)
 637				pr_err("Swap will be unusable! Try swapon -a.\n");
 638
 639			return;
 640		}
 641	}
 642#endif
 643
 644	switch (hibernation_mode) {
 645	case HIBERNATION_REBOOT:
 646		kernel_restart(NULL);
 647		break;
 648	case HIBERNATION_PLATFORM:
 649		hibernation_platform_enter();
 650		/* Fall through */
 651	case HIBERNATION_SHUTDOWN:
 652		if (pm_power_off)
 653			kernel_power_off();
 654		break;
 655	}
 656	kernel_halt();
 657	/*
 658	 * Valid image is on the disk, if we continue we risk serious data
 659	 * corruption after resume.
 660	 */
 661	pr_crit("Power down manually\n");
 662	while (1)
 663		cpu_relax();
 664}
 665
 666static int load_image_and_restore(void)
 667{
 668	int error;
 669	unsigned int flags;
 670
 671	pm_pr_dbg("Loading hibernation image.\n");
 672
 673	lock_device_hotplug();
 674	error = create_basic_memory_bitmaps();
 675	if (error)
 676		goto Unlock;
 677
 678	error = swsusp_read(&flags);
 679	swsusp_close(FMODE_READ);
 680	if (!error)
 681		hibernation_restore(flags & SF_PLATFORM_MODE);
 682
 683	pr_err("Failed to load hibernation image, recovering.\n");
 684	swsusp_free();
 685	free_basic_memory_bitmaps();
 686 Unlock:
 687	unlock_device_hotplug();
 688
 689	return error;
 690}
 691
 692/**
 693 * hibernate - Carry out system hibernation, including saving the image.
 694 */
 695int hibernate(void)
 696{
 697	int error, nr_calls = 0;
 698	bool snapshot_test = false;
 699
 700	if (!hibernation_available()) {
 701		pm_pr_dbg("Hibernation not available.\n");
 702		return -EPERM;
 703	}
 704
 705	lock_system_sleep();
 706	/* The snapshot device should not be opened while we're running */
 707	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 708		error = -EBUSY;
 709		goto Unlock;
 710	}
 711
 712	pr_info("hibernation entry\n");
 713	pm_prepare_console();
 714	error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 715	if (error) {
 716		nr_calls--;
 717		goto Exit;
 718	}
 719
 720	ksys_sync_helper();
 721
 722	error = freeze_processes();
 723	if (error)
 724		goto Exit;
 725
 726	lock_device_hotplug();
 727	/* Allocate memory management structures */
 728	error = create_basic_memory_bitmaps();
 729	if (error)
 730		goto Thaw;
 731
 732	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 733	if (error || freezer_test_done)
 734		goto Free_bitmaps;
 735
 736	if (in_suspend) {
 737		unsigned int flags = 0;
 738
 739		if (hibernation_mode == HIBERNATION_PLATFORM)
 740			flags |= SF_PLATFORM_MODE;
 741		if (nocompress)
 742			flags |= SF_NOCOMPRESS_MODE;
 743		else
 744		        flags |= SF_CRC32_MODE;
 745
 746		pm_pr_dbg("Writing image.\n");
 747		error = swsusp_write(flags);
 748		swsusp_free();
 749		if (!error) {
 750			if (hibernation_mode == HIBERNATION_TEST_RESUME)
 751				snapshot_test = true;
 752			else
 753				power_down();
 754		}
 755		in_suspend = 0;
 756		pm_restore_gfp_mask();
 757	} else {
 758		pm_pr_dbg("Image restored successfully.\n");
 759	}
 760
 761 Free_bitmaps:
 762	free_basic_memory_bitmaps();
 763 Thaw:
 764	unlock_device_hotplug();
 765	if (snapshot_test) {
 766		pm_pr_dbg("Checking hibernation image\n");
 767		error = swsusp_check();
 768		if (!error)
 769			error = load_image_and_restore();
 770	}
 771	thaw_processes();
 772
 773	/* Don't bother checking whether freezer_test_done is true */
 774	freezer_test_done = false;
 775 Exit:
 776	__pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 777	pm_restore_console();
 778	atomic_inc(&snapshot_device_available);
 779 Unlock:
 780	unlock_system_sleep();
 781	pr_info("hibernation exit\n");
 782
 783	return error;
 784}
 785
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 786
 787/**
 788 * software_resume - Resume from a saved hibernation image.
 789 *
 790 * This routine is called as a late initcall, when all devices have been
 791 * discovered and initialized already.
 792 *
 793 * The image reading code is called to see if there is a hibernation image
 794 * available for reading.  If that is the case, devices are quiesced and the
 795 * contents of memory is restored from the saved image.
 796 *
 797 * If this is successful, control reappears in the restored target kernel in
 798 * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 799 * attempts to recover gracefully and make the kernel return to the normal mode
 800 * of operation.
 801 */
 802static int software_resume(void)
 803{
 804	int error, nr_calls = 0;
 805
 806	/*
 807	 * If the user said "noresume".. bail out early.
 808	 */
 809	if (noresume || !hibernation_available())
 810		return 0;
 811
 812	/*
 813	 * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 814	 * is configured into the kernel. Since the regular hibernate
 815	 * trigger path is via sysfs which takes a buffer mutex before
 816	 * calling hibernate functions (which take system_transition_mutex)
 817	 * this can cause lockdep to complain about a possible ABBA deadlock
 818	 * which cannot happen since we're in the boot code here and
 819	 * sysfs can't be invoked yet. Therefore, we use a subclass
 820	 * here to avoid lockdep complaining.
 821	 */
 822	mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 823
 824	if (swsusp_resume_device)
 825		goto Check_image;
 826
 827	if (!strlen(resume_file)) {
 828		error = -ENOENT;
 829		goto Unlock;
 830	}
 831
 832	pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 833
 834	if (resume_delay) {
 835		pr_info("Waiting %dsec before reading resume device ...\n",
 836			resume_delay);
 837		ssleep(resume_delay);
 838	}
 839
 840	/* Check if the device is there */
 841	swsusp_resume_device = name_to_dev_t(resume_file);
 842
 843	/*
 844	 * name_to_dev_t is ineffective to verify parition if resume_file is in
 845	 * integer format. (e.g. major:minor)
 846	 */
 847	if (isdigit(resume_file[0]) && resume_wait) {
 848		int partno;
 849		while (!get_gendisk(swsusp_resume_device, &partno))
 850			msleep(10);
 851	}
 852
 853	if (!swsusp_resume_device) {
 854		/*
 855		 * Some device discovery might still be in progress; we need
 856		 * to wait for this to finish.
 857		 */
 858		wait_for_device_probe();
 859
 860		if (resume_wait) {
 861			while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 862				msleep(10);
 863			async_synchronize_full();
 864		}
 865
 866		swsusp_resume_device = name_to_dev_t(resume_file);
 867		if (!swsusp_resume_device) {
 868			error = -ENODEV;
 869			goto Unlock;
 870		}
 871	}
 872
 873 Check_image:
 874	pm_pr_dbg("Hibernation image partition %d:%d present\n",
 875		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 876
 877	pm_pr_dbg("Looking for hibernation image.\n");
 878	error = swsusp_check();
 879	if (error)
 880		goto Unlock;
 881
 882	/* The snapshot device should not be opened while we're running */
 883	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 884		error = -EBUSY;
 885		swsusp_close(FMODE_READ);
 886		goto Unlock;
 887	}
 888
 889	pr_info("resume from hibernation\n");
 890	pm_prepare_console();
 891	error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 892	if (error) {
 893		nr_calls--;
 894		goto Close_Finish;
 895	}
 896
 897	pm_pr_dbg("Preparing processes for restore.\n");
 898	error = freeze_processes();
 899	if (error)
 900		goto Close_Finish;
 
 
 
 
 
 
 
 901	error = load_image_and_restore();
 902	thaw_processes();
 903 Finish:
 904	__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 905	pm_restore_console();
 906	pr_info("resume from hibernation failed (%d)\n", error);
 907	atomic_inc(&snapshot_device_available);
 908	/* For success case, the suspend path will release the lock */
 909 Unlock:
 910	mutex_unlock(&system_transition_mutex);
 911	pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 912	return error;
 913 Close_Finish:
 914	swsusp_close(FMODE_READ);
 915	goto Finish;
 916}
 917
 918late_initcall_sync(software_resume);
 919
 920
 921static const char * const hibernation_modes[] = {
 922	[HIBERNATION_PLATFORM]	= "platform",
 923	[HIBERNATION_SHUTDOWN]	= "shutdown",
 924	[HIBERNATION_REBOOT]	= "reboot",
 925#ifdef CONFIG_SUSPEND
 926	[HIBERNATION_SUSPEND]	= "suspend",
 927#endif
 928	[HIBERNATION_TEST_RESUME]	= "test_resume",
 929};
 930
 931/*
 932 * /sys/power/disk - Control hibernation mode.
 933 *
 934 * Hibernation can be handled in several ways.  There are a few different ways
 935 * to put the system into the sleep state: using the platform driver (e.g. ACPI
 936 * or other hibernation_ops), powering it off or rebooting it (for testing
 937 * mostly).
 938 *
 939 * The sysfs file /sys/power/disk provides an interface for selecting the
 940 * hibernation mode to use.  Reading from this file causes the available modes
 941 * to be printed.  There are 3 modes that can be supported:
 942 *
 943 *	'platform'
 944 *	'shutdown'
 945 *	'reboot'
 946 *
 947 * If a platform hibernation driver is in use, 'platform' will be supported
 948 * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 949 * The selected option (i.e. the one corresponding to the current value of
 950 * hibernation_mode) is enclosed by a square bracket.
 951 *
 952 * To select a given hibernation mode it is necessary to write the mode's
 953 * string representation (as returned by reading from /sys/power/disk) back
 954 * into /sys/power/disk.
 955 */
 956
 957static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 958			 char *buf)
 959{
 960	int i;
 961	char *start = buf;
 962
 963	if (!hibernation_available())
 964		return sprintf(buf, "[disabled]\n");
 965
 966	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 967		if (!hibernation_modes[i])
 968			continue;
 969		switch (i) {
 970		case HIBERNATION_SHUTDOWN:
 971		case HIBERNATION_REBOOT:
 972#ifdef CONFIG_SUSPEND
 973		case HIBERNATION_SUSPEND:
 974#endif
 975		case HIBERNATION_TEST_RESUME:
 976			break;
 977		case HIBERNATION_PLATFORM:
 978			if (hibernation_ops)
 979				break;
 980			/* not a valid mode, continue with loop */
 981			continue;
 982		}
 983		if (i == hibernation_mode)
 984			buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 985		else
 986			buf += sprintf(buf, "%s ", hibernation_modes[i]);
 987	}
 988	buf += sprintf(buf, "\n");
 989	return buf-start;
 990}
 991
 992static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 993			  const char *buf, size_t n)
 994{
 995	int error = 0;
 996	int i;
 997	int len;
 998	char *p;
 999	int mode = HIBERNATION_INVALID;
1000
1001	if (!hibernation_available())
1002		return -EPERM;
1003
1004	p = memchr(buf, '\n', n);
1005	len = p ? p - buf : n;
1006
1007	lock_system_sleep();
1008	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1009		if (len == strlen(hibernation_modes[i])
1010		    && !strncmp(buf, hibernation_modes[i], len)) {
1011			mode = i;
1012			break;
1013		}
1014	}
1015	if (mode != HIBERNATION_INVALID) {
1016		switch (mode) {
1017		case HIBERNATION_SHUTDOWN:
1018		case HIBERNATION_REBOOT:
1019#ifdef CONFIG_SUSPEND
1020		case HIBERNATION_SUSPEND:
1021#endif
1022		case HIBERNATION_TEST_RESUME:
1023			hibernation_mode = mode;
1024			break;
1025		case HIBERNATION_PLATFORM:
1026			if (hibernation_ops)
1027				hibernation_mode = mode;
1028			else
1029				error = -EINVAL;
1030		}
1031	} else
1032		error = -EINVAL;
1033
1034	if (!error)
1035		pm_pr_dbg("Hibernation mode set to '%s'\n",
1036			       hibernation_modes[mode]);
1037	unlock_system_sleep();
1038	return error ? error : n;
1039}
1040
1041power_attr(disk);
1042
1043static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1044			   char *buf)
1045{
1046	return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1047		       MINOR(swsusp_resume_device));
1048}
1049
1050static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1051			    const char *buf, size_t n)
1052{
1053	dev_t res;
1054	int len = n;
1055	char *name;
1056
1057	if (len && buf[len-1] == '\n')
1058		len--;
1059	name = kstrndup(buf, len, GFP_KERNEL);
1060	if (!name)
1061		return -ENOMEM;
1062
1063	res = name_to_dev_t(name);
1064	kfree(name);
1065	if (!res)
1066		return -EINVAL;
1067
1068	lock_system_sleep();
1069	swsusp_resume_device = res;
1070	unlock_system_sleep();
1071	pm_pr_dbg("Configured resume from disk to %u\n", swsusp_resume_device);
 
1072	noresume = 0;
1073	software_resume();
1074	return n;
1075}
1076
1077power_attr(resume);
1078
1079static ssize_t resume_offset_show(struct kobject *kobj,
1080				  struct kobj_attribute *attr, char *buf)
1081{
1082	return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1083}
1084
1085static ssize_t resume_offset_store(struct kobject *kobj,
1086				   struct kobj_attribute *attr, const char *buf,
1087				   size_t n)
1088{
1089	unsigned long long offset;
1090	int rc;
1091
1092	rc = kstrtoull(buf, 0, &offset);
1093	if (rc)
1094		return rc;
1095	swsusp_resume_block = offset;
1096
1097	return n;
1098}
1099
1100power_attr(resume_offset);
1101
1102static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1103			       char *buf)
1104{
1105	return sprintf(buf, "%lu\n", image_size);
1106}
1107
1108static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1109				const char *buf, size_t n)
1110{
1111	unsigned long size;
1112
1113	if (sscanf(buf, "%lu", &size) == 1) {
1114		image_size = size;
1115		return n;
1116	}
1117
1118	return -EINVAL;
1119}
1120
1121power_attr(image_size);
1122
1123static ssize_t reserved_size_show(struct kobject *kobj,
1124				  struct kobj_attribute *attr, char *buf)
1125{
1126	return sprintf(buf, "%lu\n", reserved_size);
1127}
1128
1129static ssize_t reserved_size_store(struct kobject *kobj,
1130				   struct kobj_attribute *attr,
1131				   const char *buf, size_t n)
1132{
1133	unsigned long size;
1134
1135	if (sscanf(buf, "%lu", &size) == 1) {
1136		reserved_size = size;
1137		return n;
1138	}
1139
1140	return -EINVAL;
1141}
1142
1143power_attr(reserved_size);
1144
1145static struct attribute * g[] = {
1146	&disk_attr.attr,
1147	&resume_offset_attr.attr,
1148	&resume_attr.attr,
1149	&image_size_attr.attr,
1150	&reserved_size_attr.attr,
1151	NULL,
1152};
1153
1154
1155static const struct attribute_group attr_group = {
1156	.attrs = g,
1157};
1158
1159
1160static int __init pm_disk_init(void)
1161{
1162	return sysfs_create_group(power_kobj, &attr_group);
1163}
1164
1165core_initcall(pm_disk_init);
1166
1167
1168static int __init resume_setup(char *str)
1169{
1170	if (noresume)
1171		return 1;
1172
1173	strncpy( resume_file, str, 255 );
1174	return 1;
1175}
1176
1177static int __init resume_offset_setup(char *str)
1178{
1179	unsigned long long offset;
1180
1181	if (noresume)
1182		return 1;
1183
1184	if (sscanf(str, "%llu", &offset) == 1)
1185		swsusp_resume_block = offset;
1186
1187	return 1;
1188}
1189
1190static int __init hibernate_setup(char *str)
1191{
1192	if (!strncmp(str, "noresume", 8)) {
1193		noresume = 1;
1194	} else if (!strncmp(str, "nocompress", 10)) {
1195		nocompress = 1;
1196	} else if (!strncmp(str, "no", 2)) {
1197		noresume = 1;
1198		nohibernate = 1;
1199	} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1200		   && !strncmp(str, "protect_image", 13)) {
1201		enable_restore_image_protection();
1202	}
1203	return 1;
1204}
1205
1206static int __init noresume_setup(char *str)
1207{
1208	noresume = 1;
1209	return 1;
1210}
1211
1212static int __init resumewait_setup(char *str)
1213{
1214	resume_wait = 1;
1215	return 1;
1216}
1217
1218static int __init resumedelay_setup(char *str)
1219{
1220	int rc = kstrtouint(str, 0, &resume_delay);
1221
1222	if (rc)
1223		return rc;
1224	return 1;
1225}
1226
1227static int __init nohibernate_setup(char *str)
1228{
1229	noresume = 1;
1230	nohibernate = 1;
1231	return 1;
1232}
1233
1234__setup("noresume", noresume_setup);
1235__setup("resume_offset=", resume_offset_setup);
1236__setup("resume=", resume_setup);
1237__setup("hibernate=", hibernate_setup);
1238__setup("resumewait", resumewait_setup);
1239__setup("resumedelay=", resumedelay_setup);
1240__setup("nohibernate", nohibernate_setup);