Root/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 *
9 * This file is released under the GPLv2.
10 */
11
12#include <linux/export.h>
13#include <linux/suspend.h>
14#include <linux/syscalls.h>
15#include <linux/reboot.h>
16#include <linux/string.h>
17#include <linux/device.h>
18#include <linux/async.h>
19#include <linux/delay.h>
20#include <linux/fs.h>
21#include <linux/mount.h>
22#include <linux/pm.h>
23#include <linux/console.h>
24#include <linux/cpu.h>
25#include <linux/freezer.h>
26#include <linux/gfp.h>
27#include <linux/syscore_ops.h>
28#include <linux/ctype.h>
29#include <linux/genhd.h>
30
31#include "power.h"
32
33
34static int nocompress;
35static int noresume;
36static int resume_wait;
37static int resume_delay;
38static char resume_file[256] = CONFIG_PM_STD_PARTITION;
39dev_t swsusp_resume_device;
40sector_t swsusp_resume_block;
41int in_suspend __nosavedata;
42
43enum {
44    HIBERNATION_INVALID,
45    HIBERNATION_PLATFORM,
46    HIBERNATION_SHUTDOWN,
47    HIBERNATION_REBOOT,
48    /* keep last */
49    __HIBERNATION_AFTER_LAST
50};
51#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
52#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
53
54static int hibernation_mode = HIBERNATION_SHUTDOWN;
55
56bool freezer_test_done;
57
58static const struct platform_hibernation_ops *hibernation_ops;
59
60/**
61 * hibernation_set_ops - Set the global hibernate operations.
62 * @ops: Hibernation operations to use in subsequent hibernation transitions.
63 */
64void hibernation_set_ops(const struct platform_hibernation_ops *ops)
65{
66    if (ops && !(ops->begin && ops->end && ops->pre_snapshot
67        && ops->prepare && ops->finish && ops->enter && ops->pre_restore
68        && ops->restore_cleanup && ops->leave)) {
69        WARN_ON(1);
70        return;
71    }
72    lock_system_sleep();
73    hibernation_ops = ops;
74    if (ops)
75        hibernation_mode = HIBERNATION_PLATFORM;
76    else if (hibernation_mode == HIBERNATION_PLATFORM)
77        hibernation_mode = HIBERNATION_SHUTDOWN;
78
79    unlock_system_sleep();
80}
81
82static bool entering_platform_hibernation;
83
84bool system_entering_hibernation(void)
85{
86    return entering_platform_hibernation;
87}
88EXPORT_SYMBOL(system_entering_hibernation);
89
90#ifdef CONFIG_PM_DEBUG
91static void hibernation_debug_sleep(void)
92{
93    printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
94    mdelay(5000);
95}
96
97static int hibernation_test(int level)
98{
99    if (pm_test_level == level) {
100        hibernation_debug_sleep();
101        return 1;
102    }
103    return 0;
104}
105#else /* !CONFIG_PM_DEBUG */
106static int hibernation_test(int level) { return 0; }
107#endif /* !CONFIG_PM_DEBUG */
108
109/**
110 * platform_begin - Call platform to start hibernation.
111 * @platform_mode: Whether or not to use the platform driver.
112 */
113static int platform_begin(int platform_mode)
114{
115    return (platform_mode && hibernation_ops) ?
116        hibernation_ops->begin() : 0;
117}
118
119/**
120 * platform_end - Call platform to finish transition to the working state.
121 * @platform_mode: Whether or not to use the platform driver.
122 */
123static void platform_end(int platform_mode)
124{
125    if (platform_mode && hibernation_ops)
126        hibernation_ops->end();
127}
128
129/**
130 * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
131 * @platform_mode: Whether or not to use the platform driver.
132 *
133 * Use the platform driver to prepare the system for creating a hibernate image,
134 * if so configured, and return an error code if that fails.
135 */
136
137static int platform_pre_snapshot(int platform_mode)
138{
139    return (platform_mode && hibernation_ops) ?
140        hibernation_ops->pre_snapshot() : 0;
141}
142
143/**
144 * platform_leave - Call platform to prepare a transition to the working state.
145 * @platform_mode: Whether or not to use the platform driver.
146 *
147 * Use the platform driver prepare to prepare the machine for switching to the
148 * normal mode of operation.
149 *
150 * This routine is called on one CPU with interrupts disabled.
151 */
152static void platform_leave(int platform_mode)
153{
154    if (platform_mode && hibernation_ops)
155        hibernation_ops->leave();
156}
157
158/**
159 * platform_finish - Call platform to switch the system to the working state.
160 * @platform_mode: Whether or not to use the platform driver.
161 *
162 * Use the platform driver to switch the machine to the normal mode of
163 * operation.
164 *
165 * This routine must be called after platform_prepare().
166 */
167static void platform_finish(int platform_mode)
168{
169    if (platform_mode && hibernation_ops)
170        hibernation_ops->finish();
171}
172
173/**
174 * platform_pre_restore - Prepare for hibernate image restoration.
175 * @platform_mode: Whether or not to use the platform driver.
176 *
177 * Use the platform driver to prepare the system for resume from a hibernation
178 * image.
179 *
180 * If the restore fails after this function has been called,
181 * platform_restore_cleanup() must be called.
182 */
183static int platform_pre_restore(int platform_mode)
184{
185    return (platform_mode && hibernation_ops) ?
186        hibernation_ops->pre_restore() : 0;
187}
188
189/**
190 * platform_restore_cleanup - Switch to the working state after failing restore.
191 * @platform_mode: Whether or not to use the platform driver.
192 *
193 * Use the platform driver to switch the system to the normal mode of operation
194 * after a failing restore.
195 *
196 * If platform_pre_restore() has been called before the failing restore, this
197 * function must be called too, regardless of the result of
198 * platform_pre_restore().
199 */
200static void platform_restore_cleanup(int platform_mode)
201{
202    if (platform_mode && hibernation_ops)
203        hibernation_ops->restore_cleanup();
204}
205
206/**
207 * platform_recover - Recover from a failure to suspend devices.
208 * @platform_mode: Whether or not to use the platform driver.
209 */
210static void platform_recover(int platform_mode)
211{
212    if (platform_mode && hibernation_ops && hibernation_ops->recover)
213        hibernation_ops->recover();
214}
215
216/**
217 * swsusp_show_speed - Print time elapsed between two events during hibernation.
218 * @start: Starting event.
219 * @stop: Final event.
220 * @nr_pages: Number of memory pages processed between @start and @stop.
221 * @msg: Additional diagnostic message to print.
222 */
223void swsusp_show_speed(struct timeval *start, struct timeval *stop,
224            unsigned nr_pages, char *msg)
225{
226    s64 elapsed_centisecs64;
227    int centisecs;
228    int k;
229    int kps;
230
231    elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
232    do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
233    centisecs = elapsed_centisecs64;
234    if (centisecs == 0)
235        centisecs = 1; /* avoid div-by-zero */
236    k = nr_pages * (PAGE_SIZE / 1024);
237    kps = (k * 100) / centisecs;
238    printk(KERN_INFO "PM: %s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n",
239            msg, k,
240            centisecs / 100, centisecs % 100,
241            kps / 1000, (kps % 1000) / 10);
242}
243
244/**
245 * create_image - Create a hibernation image.
246 * @platform_mode: Whether or not to use the platform driver.
247 *
248 * Execute device drivers' "late" and "noirq" freeze callbacks, create a
249 * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
250 *
251 * Control reappears in this routine after the subsequent restore.
252 */
253static int create_image(int platform_mode)
254{
255    int error;
256
257    error = dpm_suspend_end(PMSG_FREEZE);
258    if (error) {
259        printk(KERN_ERR "PM: Some devices failed to power down, "
260            "aborting hibernation\n");
261        return error;
262    }
263
264    error = platform_pre_snapshot(platform_mode);
265    if (error || hibernation_test(TEST_PLATFORM))
266        goto Platform_finish;
267
268    error = disable_nonboot_cpus();
269    if (error || hibernation_test(TEST_CPUS))
270        goto Enable_cpus;
271
272    local_irq_disable();
273
274    error = syscore_suspend();
275    if (error) {
276        printk(KERN_ERR "PM: Some system devices failed to power down, "
277            "aborting hibernation\n");
278        goto Enable_irqs;
279    }
280
281    if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
282        goto Power_up;
283
284    in_suspend = 1;
285    save_processor_state();
286    error = swsusp_arch_suspend();
287    if (error)
288        printk(KERN_ERR "PM: Error %d creating hibernation image\n",
289            error);
290    /* Restore control flow magically appears here */
291    restore_processor_state();
292    if (!in_suspend) {
293        events_check_enabled = false;
294        platform_leave(platform_mode);
295    }
296
297 Power_up:
298    syscore_resume();
299
300 Enable_irqs:
301    local_irq_enable();
302
303 Enable_cpus:
304    enable_nonboot_cpus();
305
306 Platform_finish:
307    platform_finish(platform_mode);
308
309    dpm_resume_start(in_suspend ?
310        (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
311
312    return error;
313}
314
315/**
316 * hibernation_snapshot - Quiesce devices and create a hibernation image.
317 * @platform_mode: If set, use platform driver to prepare for the transition.
318 *
319 * This routine must be called with pm_mutex held.
320 */
321int hibernation_snapshot(int platform_mode)
322{
323    pm_message_t msg;
324    int error;
325
326    error = platform_begin(platform_mode);
327    if (error)
328        goto Close;
329
330    /* Preallocate image memory before shutting down devices. */
331    error = hibernate_preallocate_memory();
332    if (error)
333        goto Close;
334
335    error = freeze_kernel_threads();
336    if (error)
337        goto Cleanup;
338
339    if (hibernation_test(TEST_FREEZER)) {
340
341        /*
342         * Indicate to the caller that we are returning due to a
343         * successful freezer test.
344         */
345        freezer_test_done = true;
346        goto Thaw;
347    }
348
349    error = dpm_prepare(PMSG_FREEZE);
350    if (error) {
351        dpm_complete(PMSG_RECOVER);
352        goto Thaw;
353    }
354
355    suspend_console();
356    pm_restrict_gfp_mask();
357
358    error = dpm_suspend(PMSG_FREEZE);
359
360    if (error || hibernation_test(TEST_DEVICES))
361        platform_recover(platform_mode);
362    else
363        error = create_image(platform_mode);
364
365    /*
366     * In the case that we call create_image() above, the control
367     * returns here (1) after the image has been created or the
368     * image creation has failed and (2) after a successful restore.
369     */
370
371    /* We may need to release the preallocated image pages here. */
372    if (error || !in_suspend)
373        swsusp_free();
374
375    msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
376    dpm_resume(msg);
377
378    if (error || !in_suspend)
379        pm_restore_gfp_mask();
380
381    resume_console();
382    dpm_complete(msg);
383
384 Close:
385    platform_end(platform_mode);
386    return error;
387
388 Thaw:
389    thaw_kernel_threads();
390 Cleanup:
391    swsusp_free();
392    goto Close;
393}
394
395/**
396 * resume_target_kernel - Restore system state from a hibernation image.
397 * @platform_mode: Whether or not to use the platform driver.
398 *
399 * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
400 * contents of highmem that have not been restored yet from the image and run
401 * the low-level code that will restore the remaining contents of memory and
402 * switch to the just restored target kernel.
403 */
404static int resume_target_kernel(bool platform_mode)
405{
406    int error;
407
408    error = dpm_suspend_end(PMSG_QUIESCE);
409    if (error) {
410        printk(KERN_ERR "PM: Some devices failed to power down, "
411            "aborting resume\n");
412        return error;
413    }
414
415    error = platform_pre_restore(platform_mode);
416    if (error)
417        goto Cleanup;
418
419    error = disable_nonboot_cpus();
420    if (error)
421        goto Enable_cpus;
422
423    local_irq_disable();
424
425    error = syscore_suspend();
426    if (error)
427        goto Enable_irqs;
428
429    save_processor_state();
430    error = restore_highmem();
431    if (!error) {
432        error = swsusp_arch_resume();
433        /*
434         * The code below is only ever reached in case of a failure.
435         * Otherwise, execution continues at the place where
436         * swsusp_arch_suspend() was called.
437         */
438        BUG_ON(!error);
439        /*
440         * This call to restore_highmem() reverts the changes made by
441         * the previous one.
442         */
443        restore_highmem();
444    }
445    /*
446     * The only reason why swsusp_arch_resume() can fail is memory being
447     * very tight, so we have to free it as soon as we can to avoid
448     * subsequent failures.
449     */
450    swsusp_free();
451    restore_processor_state();
452    touch_softlockup_watchdog();
453
454    syscore_resume();
455
456 Enable_irqs:
457    local_irq_enable();
458
459 Enable_cpus:
460    enable_nonboot_cpus();
461
462 Cleanup:
463    platform_restore_cleanup(platform_mode);
464
465    dpm_resume_start(PMSG_RECOVER);
466
467    return error;
468}
469
470/**
471 * hibernation_restore - Quiesce devices and restore from a hibernation image.
472 * @platform_mode: If set, use platform driver to prepare for the transition.
473 *
474 * This routine must be called with pm_mutex held. If it is successful, control
475 * reappears in the restored target kernel in hibernation_snapshot().
476 */
477int hibernation_restore(int platform_mode)
478{
479    int error;
480
481    pm_prepare_console();
482    suspend_console();
483    pm_restrict_gfp_mask();
484    error = dpm_suspend_start(PMSG_QUIESCE);
485    if (!error) {
486        error = resume_target_kernel(platform_mode);
487        dpm_resume_end(PMSG_RECOVER);
488    }
489    pm_restore_gfp_mask();
490    resume_console();
491    pm_restore_console();
492    return error;
493}
494
495/**
496 * hibernation_platform_enter - Power off the system using the platform driver.
497 */
498int hibernation_platform_enter(void)
499{
500    int error;
501
502    if (!hibernation_ops)
503        return -ENOSYS;
504
505    /*
506     * We have cancelled the power transition by running
507     * hibernation_ops->finish() before saving the image, so we should let
508     * the firmware know that we're going to enter the sleep state after all
509     */
510    error = hibernation_ops->begin();
511    if (error)
512        goto Close;
513
514    entering_platform_hibernation = true;
515    suspend_console();
516    error = dpm_suspend_start(PMSG_HIBERNATE);
517    if (error) {
518        if (hibernation_ops->recover)
519            hibernation_ops->recover();
520        goto Resume_devices;
521    }
522
523    error = dpm_suspend_end(PMSG_HIBERNATE);
524    if (error)
525        goto Resume_devices;
526
527    error = hibernation_ops->prepare();
528    if (error)
529        goto Platform_finish;
530
531    error = disable_nonboot_cpus();
532    if (error)
533        goto Platform_finish;
534
535    local_irq_disable();
536    syscore_suspend();
537    if (pm_wakeup_pending()) {
538        error = -EAGAIN;
539        goto Power_up;
540    }
541
542    hibernation_ops->enter();
543    /* We should never get here */
544    while (1);
545
546 Power_up:
547    syscore_resume();
548    local_irq_enable();
549    enable_nonboot_cpus();
550
551 Platform_finish:
552    hibernation_ops->finish();
553
554    dpm_resume_start(PMSG_RESTORE);
555
556 Resume_devices:
557    entering_platform_hibernation = false;
558    dpm_resume_end(PMSG_RESTORE);
559    resume_console();
560
561 Close:
562    hibernation_ops->end();
563
564    return error;
565}
566
567/**
568 * power_down - Shut the machine down for hibernation.
569 *
570 * Use the platform driver, if configured, to put the system into the sleep
571 * state corresponding to hibernation, or try to power it off or reboot,
572 * depending on the value of hibernation_mode.
573 */
574static void power_down(void)
575{
576    switch (hibernation_mode) {
577    case HIBERNATION_REBOOT:
578        kernel_restart(NULL);
579        break;
580    case HIBERNATION_PLATFORM:
581        hibernation_platform_enter();
582    case HIBERNATION_SHUTDOWN:
583        kernel_power_off();
584        break;
585    }
586    kernel_halt();
587    /*
588     * Valid image is on the disk, if we continue we risk serious data
589     * corruption after resume.
590     */
591    printk(KERN_CRIT "PM: Please power down manually\n");
592    while(1);
593}
594
595/**
596 * hibernate - Carry out system hibernation, including saving the image.
597 */
598int hibernate(void)
599{
600    int error;
601
602    lock_system_sleep();
603    /* The snapshot device should not be opened while we're running */
604    if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
605        error = -EBUSY;
606        goto Unlock;
607    }
608
609    pm_prepare_console();
610    error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
611    if (error)
612        goto Exit;
613
614    /* Allocate memory management structures */
615    error = create_basic_memory_bitmaps();
616    if (error)
617        goto Exit;
618
619    printk(KERN_INFO "PM: Syncing filesystems ... ");
620    sys_sync();
621    printk("done.\n");
622
623    error = freeze_processes();
624    if (error)
625        goto Free_bitmaps;
626
627    error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
628    if (error || freezer_test_done)
629        goto Thaw;
630
631    if (in_suspend) {
632        unsigned int flags = 0;
633
634        if (hibernation_mode == HIBERNATION_PLATFORM)
635            flags |= SF_PLATFORM_MODE;
636        if (nocompress)
637            flags |= SF_NOCOMPRESS_MODE;
638        else
639                flags |= SF_CRC32_MODE;
640
641        pr_debug("PM: writing image.\n");
642        error = swsusp_write(flags);
643        swsusp_free();
644        if (!error)
645            power_down();
646        in_suspend = 0;
647        pm_restore_gfp_mask();
648    } else {
649        pr_debug("PM: Image restored successfully.\n");
650    }
651
652 Thaw:
653    thaw_processes();
654
655    /* Don't bother checking whether freezer_test_done is true */
656    freezer_test_done = false;
657
658 Free_bitmaps:
659    free_basic_memory_bitmaps();
660 Exit:
661    pm_notifier_call_chain(PM_POST_HIBERNATION);
662    pm_restore_console();
663    atomic_inc(&snapshot_device_available);
664 Unlock:
665    unlock_system_sleep();
666    return error;
667}
668
669
670/**
671 * software_resume - Resume from a saved hibernation image.
672 *
673 * This routine is called as a late initcall, when all devices have been
674 * discovered and initialized already.
675 *
676 * The image reading code is called to see if there is a hibernation image
677 * available for reading. If that is the case, devices are quiesced and the
678 * contents of memory is restored from the saved image.
679 *
680 * If this is successful, control reappears in the restored target kernel in
681 * hibernation_snaphot() which returns to hibernate(). Otherwise, the routine
682 * attempts to recover gracefully and make the kernel return to the normal mode
683 * of operation.
684 */
685static int software_resume(void)
686{
687    int error;
688    unsigned int flags;
689
690    /*
691     * If the user said "noresume".. bail out early.
692     */
693    if (noresume)
694        return 0;
695
696    /*
697     * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
698     * is configured into the kernel. Since the regular hibernate
699     * trigger path is via sysfs which takes a buffer mutex before
700     * calling hibernate functions (which take pm_mutex) this can
701     * cause lockdep to complain about a possible ABBA deadlock
702     * which cannot happen since we're in the boot code here and
703     * sysfs can't be invoked yet. Therefore, we use a subclass
704     * here to avoid lockdep complaining.
705     */
706    mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
707
708    if (swsusp_resume_device)
709        goto Check_image;
710
711    if (!strlen(resume_file)) {
712        error = -ENOENT;
713        goto Unlock;
714    }
715
716    pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
717
718    if (resume_delay) {
719        printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
720            resume_delay);
721        ssleep(resume_delay);
722    }
723
724    /* Check if the device is there */
725    swsusp_resume_device = name_to_dev_t(resume_file);
726
727    /*
728     * name_to_dev_t is ineffective to verify parition if resume_file is in
729     * integer format. (e.g. major:minor)
730     */
731    if (isdigit(resume_file[0]) && resume_wait) {
732        int partno;
733        while (!get_gendisk(swsusp_resume_device, &partno))
734            msleep(10);
735    }
736
737    if (!swsusp_resume_device) {
738        /*
739         * Some device discovery might still be in progress; we need
740         * to wait for this to finish.
741         */
742        wait_for_device_probe();
743
744        if (resume_wait) {
745            while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
746                msleep(10);
747            async_synchronize_full();
748        }
749
750        swsusp_resume_device = name_to_dev_t(resume_file);
751        if (!swsusp_resume_device) {
752            error = -ENODEV;
753            goto Unlock;
754        }
755    }
756
757 Check_image:
758    pr_debug("PM: Hibernation image partition %d:%d present\n",
759        MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
760
761    pr_debug("PM: Looking for hibernation image.\n");
762    error = swsusp_check();
763    if (error)
764        goto Unlock;
765
766    /* The snapshot device should not be opened while we're running */
767    if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
768        error = -EBUSY;
769        swsusp_close(FMODE_READ);
770        goto Unlock;
771    }
772
773    pm_prepare_console();
774    error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
775    if (error)
776        goto close_finish;
777
778    error = create_basic_memory_bitmaps();
779    if (error)
780        goto close_finish;
781
782    pr_debug("PM: Preparing processes for restore.\n");
783    error = freeze_processes();
784    if (error) {
785        swsusp_close(FMODE_READ);
786        goto Done;
787    }
788
789    pr_debug("PM: Loading hibernation image.\n");
790
791    error = swsusp_read(&flags);
792    swsusp_close(FMODE_READ);
793    if (!error)
794        hibernation_restore(flags & SF_PLATFORM_MODE);
795
796    printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
797    swsusp_free();
798    thaw_processes();
799 Done:
800    free_basic_memory_bitmaps();
801 Finish:
802    pm_notifier_call_chain(PM_POST_RESTORE);
803    pm_restore_console();
804    atomic_inc(&snapshot_device_available);
805    /* For success case, the suspend path will release the lock */
806 Unlock:
807    mutex_unlock(&pm_mutex);
808    pr_debug("PM: Hibernation image not present or could not be loaded.\n");
809    return error;
810close_finish:
811    swsusp_close(FMODE_READ);
812    goto Finish;
813}
814
815late_initcall(software_resume);
816
817
818static const char * const hibernation_modes[] = {
819    [HIBERNATION_PLATFORM] = "platform",
820    [HIBERNATION_SHUTDOWN] = "shutdown",
821    [HIBERNATION_REBOOT] = "reboot",
822};
823
824/*
825 * /sys/power/disk - Control hibernation mode.
826 *
827 * Hibernation can be handled in several ways. There are a few different ways
828 * to put the system into the sleep state: using the platform driver (e.g. ACPI
829 * or other hibernation_ops), powering it off or rebooting it (for testing
830 * mostly).
831 *
832 * The sysfs file /sys/power/disk provides an interface for selecting the
833 * hibernation mode to use. Reading from this file causes the available modes
834 * to be printed. There are 3 modes that can be supported:
835 *
836 * 'platform'
837 * 'shutdown'
838 * 'reboot'
839 *
840 * If a platform hibernation driver is in use, 'platform' will be supported
841 * and will be used by default. Otherwise, 'shutdown' will be used by default.
842 * The selected option (i.e. the one corresponding to the current value of
843 * hibernation_mode) is enclosed by a square bracket.
844 *
845 * To select a given hibernation mode it is necessary to write the mode's
846 * string representation (as returned by reading from /sys/power/disk) back
847 * into /sys/power/disk.
848 */
849
850static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
851             char *buf)
852{
853    int i;
854    char *start = buf;
855
856    for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
857        if (!hibernation_modes[i])
858            continue;
859        switch (i) {
860        case HIBERNATION_SHUTDOWN:
861        case HIBERNATION_REBOOT:
862            break;
863        case HIBERNATION_PLATFORM:
864            if (hibernation_ops)
865                break;
866            /* not a valid mode, continue with loop */
867            continue;
868        }
869        if (i == hibernation_mode)
870            buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
871        else
872            buf += sprintf(buf, "%s ", hibernation_modes[i]);
873    }
874    buf += sprintf(buf, "\n");
875    return buf-start;
876}
877
878static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
879              const char *buf, size_t n)
880{
881    int error = 0;
882    int i;
883    int len;
884    char *p;
885    int mode = HIBERNATION_INVALID;
886
887    p = memchr(buf, '\n', n);
888    len = p ? p - buf : n;
889
890    lock_system_sleep();
891    for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
892        if (len == strlen(hibernation_modes[i])
893            && !strncmp(buf, hibernation_modes[i], len)) {
894            mode = i;
895            break;
896        }
897    }
898    if (mode != HIBERNATION_INVALID) {
899        switch (mode) {
900        case HIBERNATION_SHUTDOWN:
901        case HIBERNATION_REBOOT:
902            hibernation_mode = mode;
903            break;
904        case HIBERNATION_PLATFORM:
905            if (hibernation_ops)
906                hibernation_mode = mode;
907            else
908                error = -EINVAL;
909        }
910    } else
911        error = -EINVAL;
912
913    if (!error)
914        pr_debug("PM: Hibernation mode set to '%s'\n",
915             hibernation_modes[mode]);
916    unlock_system_sleep();
917    return error ? error : n;
918}
919
920power_attr(disk);
921
922static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
923               char *buf)
924{
925    return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
926               MINOR(swsusp_resume_device));
927}
928
929static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
930                const char *buf, size_t n)
931{
932    unsigned int maj, min;
933    dev_t res;
934    int ret = -EINVAL;
935
936    if (sscanf(buf, "%u:%u", &maj, &min) != 2)
937        goto out;
938
939    res = MKDEV(maj,min);
940    if (maj != MAJOR(res) || min != MINOR(res))
941        goto out;
942
943    lock_system_sleep();
944    swsusp_resume_device = res;
945    unlock_system_sleep();
946    printk(KERN_INFO "PM: Starting manual resume from disk\n");
947    noresume = 0;
948    software_resume();
949    ret = n;
950 out:
951    return ret;
952}
953
954power_attr(resume);
955
956static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
957                   char *buf)
958{
959    return sprintf(buf, "%lu\n", image_size);
960}
961
962static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
963                const char *buf, size_t n)
964{
965    unsigned long size;
966
967    if (sscanf(buf, "%lu", &size) == 1) {
968        image_size = size;
969        return n;
970    }
971
972    return -EINVAL;
973}
974
975power_attr(image_size);
976
977static ssize_t reserved_size_show(struct kobject *kobj,
978                  struct kobj_attribute *attr, char *buf)
979{
980    return sprintf(buf, "%lu\n", reserved_size);
981}
982
983static ssize_t reserved_size_store(struct kobject *kobj,
984                   struct kobj_attribute *attr,
985                   const char *buf, size_t n)
986{
987    unsigned long size;
988
989    if (sscanf(buf, "%lu", &size) == 1) {
990        reserved_size = size;
991        return n;
992    }
993
994    return -EINVAL;
995}
996
997power_attr(reserved_size);
998
999static struct attribute * g[] = {
1000    &disk_attr.attr,
1001    &resume_attr.attr,
1002    &image_size_attr.attr,
1003    &reserved_size_attr.attr,
1004    NULL,
1005};
1006
1007
1008static struct attribute_group attr_group = {
1009    .attrs = g,
1010};
1011
1012
1013static int __init pm_disk_init(void)
1014{
1015    return sysfs_create_group(power_kobj, &attr_group);
1016}
1017
1018core_initcall(pm_disk_init);
1019
1020
1021static int __init resume_setup(char *str)
1022{
1023    if (noresume)
1024        return 1;
1025
1026    strncpy( resume_file, str, 255 );
1027    return 1;
1028}
1029
1030static int __init resume_offset_setup(char *str)
1031{
1032    unsigned long long offset;
1033
1034    if (noresume)
1035        return 1;
1036
1037    if (sscanf(str, "%llu", &offset) == 1)
1038        swsusp_resume_block = offset;
1039
1040    return 1;
1041}
1042
1043static int __init hibernate_setup(char *str)
1044{
1045    if (!strncmp(str, "noresume", 8))
1046        noresume = 1;
1047    else if (!strncmp(str, "nocompress", 10))
1048        nocompress = 1;
1049    return 1;
1050}
1051
1052static int __init noresume_setup(char *str)
1053{
1054    noresume = 1;
1055    return 1;
1056}
1057
1058static int __init resumewait_setup(char *str)
1059{
1060    resume_wait = 1;
1061    return 1;
1062}
1063
1064static int __init resumedelay_setup(char *str)
1065{
1066    resume_delay = simple_strtoul(str, NULL, 0);
1067    return 1;
1068}
1069
1070__setup("noresume", noresume_setup);
1071__setup("resume_offset=", resume_offset_setup);
1072__setup("resume=", resume_setup);
1073__setup("hibernate=", hibernate_setup);
1074__setup("resumewait", resumewait_setup);
1075__setup("resumedelay=", resumedelay_setup);
1076

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