free electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/export.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/efi.h>
#include <linux/dmi.h>
#include <linux/sched.h>
#include <linux/tboot.h>
#include <linux/delay.h>
#include <acpi/reboot.h>
#include <asm/io.h>
#include <asm/apic.h>
#include <asm/io_apic.h>
#include <asm/desc.h>
#include <asm/hpet.h>
#include <asm/pgtable.h>
#include <asm/proto.h>
#include <asm/reboot_fixups.h>
#include <asm/reboot.h>
#include <asm/pci_x86.h>
#include <asm/virtext.h>
#include <asm/cpu.h>
#include <asm/nmi.h>
#include <asm/smp.h>

#include <linux/ctype.h>
#include <linux/mc146818rtc.h>
#include <asm/realmode.h>
#include <asm/x86_init.h>
#include <asm/efi.h>

/*
 * Power off function, if any
 */
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);

static const struct desc_ptr no_idt = {};

/*
 * This is set if we need to go through the 'emergency' path.
 * When machine_emergency_restart() is called, we may be on
 * an inconsistent state and won't be able to do a clean cleanup
 */
static int reboot_emergency;

/* This is set by the PCI code if either type 1 or type 2 PCI is detected */
bool port_cf9_safe = false;

/*
 * Reboot options and system auto-detection code provided by
 * Dell Inc. so their systems "just work". :-)
 */

/*
 * Some machines require the "reboot=a" commandline options
 */
static int __init set_acpi_reboot(const struct dmi_system_id *d)
{
	if (reboot_type != BOOT_ACPI) {
		reboot_type = BOOT_ACPI;
		pr_info("%s series board detected. Selecting %s-method for reboots.\n",
			d->ident, "ACPI");
	}
	return 0;
}

/*
 * Some machines require the "reboot=b" or "reboot=k"  commandline options,
 * this quirk makes that automatic.
 */
static int __init set_bios_reboot(const struct dmi_system_id *d)
{
	if (reboot_type != BOOT_BIOS) {
		reboot_type = BOOT_BIOS;
		pr_info("%s series board detected. Selecting %s-method for reboots.\n",
			d->ident, "BIOS");
	}
	return 0;
}

void __noreturn machine_real_restart(unsigned int type)
{
	local_irq_disable();

	/*
	 * Write zero to CMOS register number 0x0f, which the BIOS POST
	 * routine will recognize as telling it to do a proper reboot.  (Well
	 * that's what this book in front of me says -- it may only apply to
	 * the Phoenix BIOS though, it's not clear).  At the same time,
	 * disable NMIs by setting the top bit in the CMOS address register,
	 * as we're about to do peculiar things to the CPU.  I'm not sure if
	 * `outb_p' is needed instead of just `outb'.  Use it to be on the
	 * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
	 */
	spin_lock(&rtc_lock);
	CMOS_WRITE(0x00, 0x8f);
	spin_unlock(&rtc_lock);

	/*
	 * Switch back to the initial page table.
	 */
#ifdef CONFIG_X86_32
	load_cr3(initial_page_table);
#else
	write_cr3(real_mode_header->trampoline_pgd);
#endif

	/* Jump to the identity-mapped low memory code */
#ifdef CONFIG_X86_32
	asm volatile("jmpl *%0" : :
		     "rm" (real_mode_header->machine_real_restart_asm),
		     "a" (type));
#else
	asm volatile("ljmpl *%0" : :
		     "m" (real_mode_header->machine_real_restart_asm),
		     "D" (type));
#endif
	unreachable();
}
#ifdef CONFIG_APM_MODULE
EXPORT_SYMBOL(machine_real_restart);
#endif

/*
 * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
 */
static int __init set_pci_reboot(const struct dmi_system_id *d)
{
	if (reboot_type != BOOT_CF9_FORCE) {
		reboot_type = BOOT_CF9_FORCE;
		pr_info("%s series board detected. Selecting %s-method for reboots.\n",
			d->ident, "PCI");
	}
	return 0;
}

static int __init set_kbd_reboot(const struct dmi_system_id *d)
{
	if (reboot_type != BOOT_KBD) {
		reboot_type = BOOT_KBD;
		pr_info("%s series board detected. Selecting %s-method for reboot.\n",
			d->ident, "KBD");
	}
	return 0;
}

/*
 * This is a single dmi_table handling all reboot quirks.
 */
static struct dmi_system_id __initdata reboot_dmi_table[] = {

	/* Acer */
	{	/* Handle reboot issue on Acer Aspire one */
		.callback = set_kbd_reboot,
		.ident = "Acer Aspire One A110",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
			DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
		},
	},

	/* Apple */
	{	/* Handle problems with rebooting on Apple MacBook5 */
		.callback = set_pci_reboot,
		.ident = "Apple MacBook5",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
		},
	},
	{	/* Handle problems with rebooting on Apple MacBookPro5 */
		.callback = set_pci_reboot,
		.ident = "Apple MacBookPro5",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
		},
	},
	{	/* Handle problems with rebooting on Apple Macmini3,1 */
		.callback = set_pci_reboot,
		.ident = "Apple Macmini3,1",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
		},
	},
	{	/* Handle problems with rebooting on the iMac9,1. */
		.callback = set_pci_reboot,
		.ident = "Apple iMac9,1",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
		},
	},
	{	/* Handle problems with rebooting on the iMac10,1. */
		.callback = set_pci_reboot,
		.ident = "Apple iMac10,1",
		.matches = {
		    DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
		    DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
		},
	},

	/* ASRock */
	{	/* Handle problems with rebooting on ASRock Q1900DC-ITX */
		.callback = set_pci_reboot,
		.ident = "ASRock Q1900DC-ITX",
		.matches = {
			DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
			DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
		},
	},

	/* ASUS */
	{	/* Handle problems with rebooting on ASUS P4S800 */
		.callback = set_bios_reboot,
		.ident = "ASUS P4S800",
		.matches = {
			DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
			DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
		},
	},
	{	/* Handle problems with rebooting on ASUS EeeBook X205TA */
		.callback = set_acpi_reboot,
		.ident = "ASUS EeeBook X205TA",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
			DMI_MATCH(DMI_PRODUCT_NAME, "X205TA"),
		},
	},
	{	/* Handle problems with rebooting on ASUS EeeBook X205TAW */
		.callback = set_acpi_reboot,
		.ident = "ASUS EeeBook X205TAW",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
			DMI_MATCH(DMI_PRODUCT_NAME, "X205TAW"),
		},
	},

	/* Certec */
	{       /* Handle problems with rebooting on Certec BPC600 */
		.callback = set_pci_reboot,
		.ident = "Certec BPC600",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
			DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
		},
	},

	/* Dell */
	{	/* Handle problems with rebooting on Dell DXP061 */
		.callback = set_bios_reboot,
		.ident = "Dell DXP061",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
		},
	},
	{	/* Handle problems with rebooting on Dell E520's */
		.callback = set_bios_reboot,
		.ident = "Dell E520",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
		},
	},
	{	/* Handle problems with rebooting on the Latitude E5410. */
		.callback = set_pci_reboot,
		.ident = "Dell Latitude E5410",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
		},
	},
	{	/* Handle problems with rebooting on the Latitude E5420. */
		.callback = set_pci_reboot,
		.ident = "Dell Latitude E5420",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
		},
	},
	{	/* Handle problems with rebooting on the Latitude E6320. */
		.callback = set_pci_reboot,
		.ident = "Dell Latitude E6320",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
		},
	},
	{	/* Handle problems with rebooting on the Latitude E6420. */
		.callback = set_pci_reboot,
		.ident = "Dell Latitude E6420",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
		},
	},
	{	/* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
		.callback = set_bios_reboot,
		.ident = "Dell OptiPlex 330",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
			DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
		},
	},
	{	/* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
		.callback = set_bios_reboot,
		.ident = "Dell OptiPlex 360",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
			DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
		},
	},
	{	/* Handle problems with rebooting on Dell Optiplex 745's SFF */
		.callback = set_bios_reboot,
		.ident = "Dell OptiPlex 745",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
		},
	},
	{	/* Handle problems with rebooting on Dell Optiplex 745's DFF */
		.callback = set_bios_reboot,
		.ident = "Dell OptiPlex 745",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
			DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
		},
	},
	{	/* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
		.callback = set_bios_reboot,
		.ident = "Dell OptiPlex 745",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
			DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
		},
	},
	{	/* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
		.callback = set_bios_reboot,
		.ident = "Dell OptiPlex 760",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
			DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
		},
	},
	{	/* Handle problems with rebooting on the OptiPlex 990. */
		.callback = set_pci_reboot,
		.ident = "Dell OptiPlex 990",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
		},
	},
	{	/* Handle problems with rebooting on Dell 300's */
		.callback = set_bios_reboot,
		.ident = "Dell PowerEdge 300",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
		},
	},
	{	/* Handle problems with rebooting on Dell 1300's */
		.callback = set_bios_reboot,
		.ident = "Dell PowerEdge 1300",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
		},
	},
	{	/* Handle problems with rebooting on Dell 2400's */
		.callback = set_bios_reboot,
		.ident = "Dell PowerEdge 2400",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
		},
	},
	{	/* Handle problems with rebooting on the Dell PowerEdge C6100. */
		.callback = set_pci_reboot,
		.ident = "Dell PowerEdge C6100",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
			DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
		},
	},
	{	/* Handle problems with rebooting on the Precision M6600. */
		.callback = set_pci_reboot,
		.ident = "Dell Precision M6600",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
		},
	},
	{	/* Handle problems with rebooting on Dell T5400's */
		.callback = set_bios_reboot,
		.ident = "Dell Precision T5400",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
		},
	},
	{	/* Handle problems with rebooting on Dell T7400's */
		.callback = set_bios_reboot,
		.ident = "Dell Precision T7400",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
		},
	},
	{	/* Handle problems with rebooting on Dell XPS710 */
		.callback = set_bios_reboot,
		.ident = "Dell XPS710",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
		},
	},
	{	/* Handle problems with rebooting on Dell Optiplex 7450 AIO */
		.callback = set_acpi_reboot,
		.ident = "Dell OptiPlex 7450 AIO",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7450 AIO"),
		},
	},

	/* Hewlett-Packard */
	{	/* Handle problems with rebooting on HP laptops */
		.callback = set_bios_reboot,
		.ident = "HP Compaq Laptop",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
			DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
		},
	},

	/* Sony */
	{	/* Handle problems with rebooting on Sony VGN-Z540N */
		.callback = set_bios_reboot,
		.ident = "Sony VGN-Z540N",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
			DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
		},
	},

	{ }
};

static int __init reboot_init(void)
{
	int rv;

	/*
	 * Only do the DMI check if reboot_type hasn't been overridden
	 * on the command line
	 */
	if (!reboot_default)
		return 0;

	/*
	 * The DMI quirks table takes precedence. If no quirks entry
	 * matches and the ACPI Hardware Reduced bit is set, force EFI
	 * reboot.
	 */
	rv = dmi_check_system(reboot_dmi_table);

	if (!rv && efi_reboot_required())
		reboot_type = BOOT_EFI;

	return 0;
}
core_initcall(reboot_init);

static inline void kb_wait(void)
{
	int i;

	for (i = 0; i < 0x10000; i++) {
		if ((inb(0x64) & 0x02) == 0)
			break;
		udelay(2);
	}
}

static void vmxoff_nmi(int cpu, struct pt_regs *regs)
{
	cpu_emergency_vmxoff();
}

/* Use NMIs as IPIs to tell all CPUs to disable virtualization */
static void emergency_vmx_disable_all(void)
{
	/* Just make sure we won't change CPUs while doing this */
	local_irq_disable();

	/*
	 * We need to disable VMX on all CPUs before rebooting, otherwise
	 * we risk hanging up the machine, because the CPU ignore INIT
	 * signals when VMX is enabled.
	 *
	 * We can't take any locks and we may be on an inconsistent
	 * state, so we use NMIs as IPIs to tell the other CPUs to disable
	 * VMX and halt.
	 *
	 * For safety, we will avoid running the nmi_shootdown_cpus()
	 * stuff unnecessarily, but we don't have a way to check
	 * if other CPUs have VMX enabled. So we will call it only if the
	 * CPU we are running on has VMX enabled.
	 *
	 * We will miss cases where VMX is not enabled on all CPUs. This
	 * shouldn't do much harm because KVM always enable VMX on all
	 * CPUs anyway. But we can miss it on the small window where KVM
	 * is still enabling VMX.
	 */
	if (cpu_has_vmx() && cpu_vmx_enabled()) {
		/* Disable VMX on this CPU. */
		cpu_vmxoff();

		/* Halt and disable VMX on the other CPUs */
		nmi_shootdown_cpus(vmxoff_nmi);

	}
}


void __attribute__((weak)) mach_reboot_fixups(void)
{
}

/*
 * To the best of our knowledge Windows compatible x86 hardware expects
 * the following on reboot:
 *
 * 1) If the FADT has the ACPI reboot register flag set, try it
 * 2) If still alive, write to the keyboard controller
 * 3) If still alive, write to the ACPI reboot register again
 * 4) If still alive, write to the keyboard controller again
 * 5) If still alive, call the EFI runtime service to reboot
 * 6) If no EFI runtime service, call the BIOS to do a reboot
 *
 * We default to following the same pattern. We also have
 * two other reboot methods: 'triple fault' and 'PCI', which
 * can be triggered via the reboot= kernel boot option or
 * via quirks.
 *
 * This means that this function can never return, it can misbehave
 * by not rebooting properly and hanging.
 */
static void native_machine_emergency_restart(void)
{
	int i;
	int attempt = 0;
	int orig_reboot_type = reboot_type;
	unsigned short mode;

	if (reboot_emergency)
		emergency_vmx_disable_all();

	tboot_shutdown(TB_SHUTDOWN_REBOOT);

	/* Tell the BIOS if we want cold or warm reboot */
	mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
	*((unsigned short *)__va(0x472)) = mode;

	/*
	 * If an EFI capsule has been registered with the firmware then
	 * override the reboot= parameter.
	 */
	if (efi_capsule_pending(NULL)) {
		pr_info("EFI capsule is pending, forcing EFI reboot.\n");
		reboot_type = BOOT_EFI;
	}

	for (;;) {
		/* Could also try the reset bit in the Hammer NB */
		switch (reboot_type) {
		case BOOT_ACPI:
			acpi_reboot();
			reboot_type = BOOT_KBD;
			break;

		case BOOT_KBD:
			mach_reboot_fixups(); /* For board specific fixups */

			for (i = 0; i < 10; i++) {
				kb_wait();
				udelay(50);
				outb(0xfe, 0x64); /* Pulse reset low */
				udelay(50);
			}
			if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
				attempt = 1;
				reboot_type = BOOT_ACPI;
			} else {
				reboot_type = BOOT_EFI;
			}
			break;

		case BOOT_EFI:
			efi_reboot(reboot_mode, NULL);
			reboot_type = BOOT_BIOS;
			break;

		case BOOT_BIOS:
			machine_real_restart(MRR_BIOS);

			/* We're probably dead after this, but... */
			reboot_type = BOOT_CF9_SAFE;
			break;

		case BOOT_CF9_FORCE:
			port_cf9_safe = true;
			/* Fall through */

		case BOOT_CF9_SAFE:
			if (port_cf9_safe) {
				u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
				u8 cf9 = inb(0xcf9) & ~reboot_code;
				outb(cf9|2, 0xcf9); /* Request hard reset */
				udelay(50);
				/* Actually do the reset */
				outb(cf9|reboot_code, 0xcf9);
				udelay(50);
			}
			reboot_type = BOOT_TRIPLE;
			break;

		case BOOT_TRIPLE:
			load_idt(&no_idt);
			__asm__ __volatile__("int3");

			/* We're probably dead after this, but... */
			reboot_type = BOOT_KBD;
			break;
		}
	}
}

void native_machine_shutdown(void)
{
	/* Stop the cpus and apics */
#ifdef CONFIG_X86_IO_APIC
	/*
	 * Disabling IO APIC before local APIC is a workaround for
	 * erratum AVR31 in "Intel Atom Processor C2000 Product Family
	 * Specification Update". In this situation, interrupts that target
	 * a Logical Processor whose Local APIC is either in the process of
	 * being hardware disabled or software disabled are neither delivered
	 * nor discarded. When this erratum occurs, the processor may hang.
	 *
	 * Even without the erratum, it still makes sense to quiet IO APIC
	 * before disabling Local APIC.
	 */
	disable_IO_APIC();
#endif

#ifdef CONFIG_SMP
	/*
	 * Stop all of the others. Also disable the local irq to
	 * not receive the per-cpu timer interrupt which may trigger
	 * scheduler's load balance.
	 */
	local_irq_disable();
	stop_other_cpus();
#endif

	lapic_shutdown();

#ifdef CONFIG_HPET_TIMER
	hpet_disable();
#endif

#ifdef CONFIG_X86_64
	x86_platform.iommu_shutdown();
#endif
}

static void __machine_emergency_restart(int emergency)
{
	reboot_emergency = emergency;
	machine_ops.emergency_restart();
}

static void native_machine_restart(char *__unused)
{
	pr_notice("machine restart\n");

	if (!reboot_force)
		machine_shutdown();
	__machine_emergency_restart(0);
}

static void native_machine_halt(void)
{
	/* Stop other cpus and apics */
	machine_shutdown();

	tboot_shutdown(TB_SHUTDOWN_HALT);

	stop_this_cpu(NULL);
}

static void native_machine_power_off(void)
{
	if (pm_power_off) {
		if (!reboot_force)
			machine_shutdown();
		pm_power_off();
	}
	/* A fallback in case there is no PM info available */
	tboot_shutdown(TB_SHUTDOWN_HALT);
}

struct machine_ops machine_ops __ro_after_init = {
	.power_off = native_machine_power_off,
	.shutdown = native_machine_shutdown,
	.emergency_restart = native_machine_emergency_restart,
	.restart = native_machine_restart,
	.halt = native_machine_halt,
#ifdef CONFIG_KEXEC_CORE
	.crash_shutdown = native_machine_crash_shutdown,
#endif
};

void machine_power_off(void)
{
	machine_ops.power_off();
}

void machine_shutdown(void)
{
	machine_ops.shutdown();
}

void machine_emergency_restart(void)
{
	__machine_emergency_restart(1);
}

void machine_restart(char *cmd)
{
	machine_ops.restart(cmd);
}

void machine_halt(void)
{
	machine_ops.halt();
}

#ifdef CONFIG_KEXEC_CORE
void machine_crash_shutdown(struct pt_regs *regs)
{
	machine_ops.crash_shutdown(regs);
}
#endif


#if defined(CONFIG_SMP)

/* This keeps a track of which one is crashing cpu. */
static int crashing_cpu;
static nmi_shootdown_cb shootdown_callback;

static atomic_t waiting_for_crash_ipi;
static int crash_ipi_issued;

static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
{
	int cpu;

	cpu = raw_smp_processor_id();

	/*
	 * Don't do anything if this handler is invoked on crashing cpu.
	 * Otherwise, system will completely hang. Crashing cpu can get
	 * an NMI if system was initially booted with nmi_watchdog parameter.
	 */
	if (cpu == crashing_cpu)
		return NMI_HANDLED;
	local_irq_disable();

	shootdown_callback(cpu, regs);

	atomic_dec(&waiting_for_crash_ipi);
	/* Assume hlt works */
	halt();
	for (;;)
		cpu_relax();

	return NMI_HANDLED;
}

static void smp_send_nmi_allbutself(void)
{
	apic->send_IPI_allbutself(NMI_VECTOR);
}

/*
 * Halt all other CPUs, calling the specified function on each of them
 *
 * This function can be used to halt all other CPUs on crash
 * or emergency reboot time. The function passed as parameter
 * will be called inside a NMI handler on all CPUs.
 */
void nmi_shootdown_cpus(nmi_shootdown_cb callback)
{
	unsigned long msecs;
	local_irq_disable();

	/* Make a note of crashing cpu. Will be used in NMI callback. */
	crashing_cpu = safe_smp_processor_id();

	shootdown_callback = callback;

	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
	/* Would it be better to replace the trap vector here? */
	if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
				 NMI_FLAG_FIRST, "crash"))
		return;		/* Return what? */
	/*
	 * Ensure the new callback function is set before sending
	 * out the NMI
	 */
	wmb();

	smp_send_nmi_allbutself();

	/* Kick CPUs looping in NMI context. */
	WRITE_ONCE(crash_ipi_issued, 1);

	msecs = 1000; /* Wait at most a second for the other cpus to stop */
	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
		mdelay(1);
		msecs--;
	}

	/* Leave the nmi callback set */
}

/*
 * Check if the crash dumping IPI got issued and if so, call its callback
 * directly. This function is used when we have already been in NMI handler.
 * It doesn't return.
 */
void run_crash_ipi_callback(struct pt_regs *regs)
{
	if (crash_ipi_issued)
		crash_nmi_callback(0, regs);
}

/* Override the weak function in kernel/panic.c */
void nmi_panic_self_stop(struct pt_regs *regs)
{
	while (1) {
		/* If no CPU is preparing crash dump, we simply loop here. */
		run_crash_ipi_callback(regs);
		cpu_relax();
	}
}

#else /* !CONFIG_SMP */
void nmi_shootdown_cpus(nmi_shootdown_cb callback)
{
	/* No other CPUs to shoot down */
}

void run_crash_ipi_callback(struct pt_regs *regs)
{
}
#endif