summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/mce.c
blob: 9a3c2a84a2acab32e4c0544d92f9633822a4a430 (plain)
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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Machine check exception handling.
 *
 * Copyright 2013 IBM Corporation
 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
 */

#undef DEBUG
#define pr_fmt(fmt) "mce: " fmt

#include <linux/hardirq.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/percpu.h>
#include <linux/export.h>
#include <linux/irq_work.h>
#include <linux/extable.h>
#include <linux/ftrace.h>
#include <linux/memblock.h>

#include <asm/interrupt.h>
#include <asm/machdep.h>
#include <asm/mce.h>
#include <asm/nmi.h>
#include <asm/asm-prototypes.h>

#include "setup.h"

static void machine_check_process_queued_event(struct irq_work *work);
static void machine_check_ue_irq_work(struct irq_work *work);
static void machine_check_ue_event(struct machine_check_event *evt);
static void machine_process_ue_event(struct work_struct *work);

static struct irq_work mce_event_process_work = {
        .func = machine_check_process_queued_event,
};

static struct irq_work mce_ue_event_irq_work = {
	.func = machine_check_ue_irq_work,
};

static DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);

static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);

int mce_register_notifier(struct notifier_block *nb)
{
	return blocking_notifier_chain_register(&mce_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(mce_register_notifier);

int mce_unregister_notifier(struct notifier_block *nb)
{
	return blocking_notifier_chain_unregister(&mce_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(mce_unregister_notifier);

static void mce_set_error_info(struct machine_check_event *mce,
			       struct mce_error_info *mce_err)
{
	mce->error_type = mce_err->error_type;
	switch (mce_err->error_type) {
	case MCE_ERROR_TYPE_UE:
		mce->u.ue_error.ue_error_type = mce_err->u.ue_error_type;
		break;
	case MCE_ERROR_TYPE_SLB:
		mce->u.slb_error.slb_error_type = mce_err->u.slb_error_type;
		break;
	case MCE_ERROR_TYPE_ERAT:
		mce->u.erat_error.erat_error_type = mce_err->u.erat_error_type;
		break;
	case MCE_ERROR_TYPE_TLB:
		mce->u.tlb_error.tlb_error_type = mce_err->u.tlb_error_type;
		break;
	case MCE_ERROR_TYPE_USER:
		mce->u.user_error.user_error_type = mce_err->u.user_error_type;
		break;
	case MCE_ERROR_TYPE_RA:
		mce->u.ra_error.ra_error_type = mce_err->u.ra_error_type;
		break;
	case MCE_ERROR_TYPE_LINK:
		mce->u.link_error.link_error_type = mce_err->u.link_error_type;
		break;
	case MCE_ERROR_TYPE_UNKNOWN:
	default:
		break;
	}
}

/*
 * Decode and save high level MCE information into per cpu buffer which
 * is an array of machine_check_event structure.
 */
void save_mce_event(struct pt_regs *regs, long handled,
		    struct mce_error_info *mce_err,
		    uint64_t nip, uint64_t addr, uint64_t phys_addr)
{
	int index = local_paca->mce_info->mce_nest_count++;
	struct machine_check_event *mce;

	mce = &local_paca->mce_info->mce_event[index];
	/*
	 * Return if we don't have enough space to log mce event.
	 * mce_nest_count may go beyond MAX_MC_EVT but that's ok,
	 * the check below will stop buffer overrun.
	 */
	if (index >= MAX_MC_EVT)
		return;

	/* Populate generic machine check info */
	mce->version = MCE_V1;
	mce->srr0 = nip;
	mce->srr1 = regs->msr;
	mce->gpr3 = regs->gpr[3];
	mce->in_use = 1;
	mce->cpu = get_paca()->paca_index;

	/* Mark it recovered if we have handled it and MSR(RI=1). */
	if (handled && (regs->msr & MSR_RI))
		mce->disposition = MCE_DISPOSITION_RECOVERED;
	else
		mce->disposition = MCE_DISPOSITION_NOT_RECOVERED;

	mce->initiator = mce_err->initiator;
	mce->severity = mce_err->severity;
	mce->sync_error = mce_err->sync_error;
	mce->error_class = mce_err->error_class;

	/*
	 * Populate the mce error_type and type-specific error_type.
	 */
	mce_set_error_info(mce, mce_err);
	if (mce->error_type == MCE_ERROR_TYPE_UE)
		mce->u.ue_error.ignore_event = mce_err->ignore_event;

	if (!addr)
		return;

	if (mce->error_type == MCE_ERROR_TYPE_TLB) {
		mce->u.tlb_error.effective_address_provided = true;
		mce->u.tlb_error.effective_address = addr;
	} else if (mce->error_type == MCE_ERROR_TYPE_SLB) {
		mce->u.slb_error.effective_address_provided = true;
		mce->u.slb_error.effective_address = addr;
	} else if (mce->error_type == MCE_ERROR_TYPE_ERAT) {
		mce->u.erat_error.effective_address_provided = true;
		mce->u.erat_error.effective_address = addr;
	} else if (mce->error_type == MCE_ERROR_TYPE_USER) {
		mce->u.user_error.effective_address_provided = true;
		mce->u.user_error.effective_address = addr;
	} else if (mce->error_type == MCE_ERROR_TYPE_RA) {
		mce->u.ra_error.effective_address_provided = true;
		mce->u.ra_error.effective_address = addr;
	} else if (mce->error_type == MCE_ERROR_TYPE_LINK) {
		mce->u.link_error.effective_address_provided = true;
		mce->u.link_error.effective_address = addr;
	} else if (mce->error_type == MCE_ERROR_TYPE_UE) {
		mce->u.ue_error.effective_address_provided = true;
		mce->u.ue_error.effective_address = addr;
		if (phys_addr != ULONG_MAX) {
			mce->u.ue_error.physical_address_provided = true;
			mce->u.ue_error.physical_address = phys_addr;
			machine_check_ue_event(mce);
		}
	}
	return;
}

/*
 * get_mce_event:
 *	mce	Pointer to machine_check_event structure to be filled.
 *	release Flag to indicate whether to free the event slot or not.
 *		0 <= do not release the mce event. Caller will invoke
 *		     release_mce_event() once event has been consumed.
 *		1 <= release the slot.
 *
 *	return	1 = success
 *		0 = failure
 *
 * get_mce_event() will be called by platform specific machine check
 * handle routine and in KVM.
 * When we call get_mce_event(), we are still in interrupt context and
 * preemption will not be scheduled until ret_from_expect() routine
 * is called.
 */
int get_mce_event(struct machine_check_event *mce, bool release)
{
	int index = local_paca->mce_info->mce_nest_count - 1;
	struct machine_check_event *mc_evt;
	int ret = 0;

	/* Sanity check */
	if (index < 0)
		return ret;

	/* Check if we have MCE info to process. */
	if (index < MAX_MC_EVT) {
		mc_evt = &local_paca->mce_info->mce_event[index];
		/* Copy the event structure and release the original */
		if (mce)
			*mce = *mc_evt;
		if (release)
			mc_evt->in_use = 0;
		ret = 1;
	}
	/* Decrement the count to free the slot. */
	if (release)
		local_paca->mce_info->mce_nest_count--;

	return ret;
}

void release_mce_event(void)
{
	get_mce_event(NULL, true);
}

static void machine_check_ue_irq_work(struct irq_work *work)
{
	schedule_work(&mce_ue_event_work);
}

/*
 * Queue up the MCE event which then can be handled later.
 */
static void machine_check_ue_event(struct machine_check_event *evt)
{
	int index;

	index = local_paca->mce_info->mce_ue_count++;
	/* If queue is full, just return for now. */
	if (index >= MAX_MC_EVT) {
		local_paca->mce_info->mce_ue_count--;
		return;
	}
	memcpy(&local_paca->mce_info->mce_ue_event_queue[index],
	       evt, sizeof(*evt));

	/* Queue work to process this event later. */
	irq_work_queue(&mce_ue_event_irq_work);
}

/*
 * Queue up the MCE event which then can be handled later.
 */
void machine_check_queue_event(void)
{
	int index;
	struct machine_check_event evt;

	if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
		return;

	index = local_paca->mce_info->mce_queue_count++;
	/* If queue is full, just return for now. */
	if (index >= MAX_MC_EVT) {
		local_paca->mce_info->mce_queue_count--;
		return;
	}
	memcpy(&local_paca->mce_info->mce_event_queue[index],
	       &evt, sizeof(evt));

	/* Queue irq work to process this event later. */
	irq_work_queue(&mce_event_process_work);
}

void mce_common_process_ue(struct pt_regs *regs,
			   struct mce_error_info *mce_err)
{
	const struct exception_table_entry *entry;

	entry = search_kernel_exception_table(regs->nip);
	if (entry) {
		mce_err->ignore_event = true;
		regs->nip = extable_fixup(entry);
	}
}

/*
 * process pending MCE event from the mce event queue. This function will be
 * called during syscall exit.
 */
static void machine_process_ue_event(struct work_struct *work)
{
	int index;
	struct machine_check_event *evt;

	while (local_paca->mce_info->mce_ue_count > 0) {
		index = local_paca->mce_info->mce_ue_count - 1;
		evt = &local_paca->mce_info->mce_ue_event_queue[index];
		blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
#ifdef CONFIG_MEMORY_FAILURE
		/*
		 * This should probably queued elsewhere, but
		 * oh! well
		 *
		 * Don't report this machine check because the caller has a
		 * asked us to ignore the event, it has a fixup handler which
		 * will do the appropriate error handling and reporting.
		 */
		if (evt->error_type == MCE_ERROR_TYPE_UE) {
			if (evt->u.ue_error.ignore_event) {
				local_paca->mce_info->mce_ue_count--;
				continue;
			}

			if (evt->u.ue_error.physical_address_provided) {
				unsigned long pfn;

				pfn = evt->u.ue_error.physical_address >>
					PAGE_SHIFT;
				memory_failure(pfn, 0);
			} else
				pr_warn("Failed to identify bad address from "
					"where the uncorrectable error (UE) "
					"was generated\n");
		}
#endif
		local_paca->mce_info->mce_ue_count--;
	}
}
/*
 * process pending MCE event from the mce event queue. This function will be
 * called during syscall exit.
 */
static void machine_check_process_queued_event(struct irq_work *work)
{
	int index;
	struct machine_check_event *evt;

	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);

	/*
	 * For now just print it to console.
	 * TODO: log this error event to FSP or nvram.
	 */
	while (local_paca->mce_info->mce_queue_count > 0) {
		index = local_paca->mce_info->mce_queue_count - 1;
		evt = &local_paca->mce_info->mce_event_queue[index];

		if (evt->error_type == MCE_ERROR_TYPE_UE &&
		    evt->u.ue_error.ignore_event) {
			local_paca->mce_info->mce_queue_count--;
			continue;
		}
		machine_check_print_event_info(evt, false, false);
		local_paca->mce_info->mce_queue_count--;
	}
}

void machine_check_print_event_info(struct machine_check_event *evt,
				    bool user_mode, bool in_guest)
{
	const char *level, *sevstr, *subtype, *err_type, *initiator;
	uint64_t ea = 0, pa = 0;
	int n = 0;
	char dar_str[50];
	char pa_str[50];
	static const char *mc_ue_types[] = {
		"Indeterminate",
		"Instruction fetch",
		"Page table walk ifetch",
		"Load/Store",
		"Page table walk Load/Store",
	};
	static const char *mc_slb_types[] = {
		"Indeterminate",
		"Parity",
		"Multihit",
	};
	static const char *mc_erat_types[] = {
		"Indeterminate",
		"Parity",
		"Multihit",
	};
	static const char *mc_tlb_types[] = {
		"Indeterminate",
		"Parity",
		"Multihit",
	};
	static const char *mc_user_types[] = {
		"Indeterminate",
		"tlbie(l) invalid",
		"scv invalid",
	};
	static const char *mc_ra_types[] = {
		"Indeterminate",
		"Instruction fetch (bad)",
		"Instruction fetch (foreign)",
		"Page table walk ifetch (bad)",
		"Page table walk ifetch (foreign)",
		"Load (bad)",
		"Store (bad)",
		"Page table walk Load/Store (bad)",
		"Page table walk Load/Store (foreign)",
		"Load/Store (foreign)",
	};
	static const char *mc_link_types[] = {
		"Indeterminate",
		"Instruction fetch (timeout)",
		"Page table walk ifetch (timeout)",
		"Load (timeout)",
		"Store (timeout)",
		"Page table walk Load/Store (timeout)",
	};
	static const char *mc_error_class[] = {
		"Unknown",
		"Hardware error",
		"Probable Hardware error (some chance of software cause)",
		"Software error",
		"Probable Software error (some chance of hardware cause)",
	};

	/* Print things out */
	if (evt->version != MCE_V1) {
		pr_err("Machine Check Exception, Unknown event version %d !\n",
		       evt->version);
		return;
	}
	switch (evt->severity) {
	case MCE_SEV_NO_ERROR:
		level = KERN_INFO;
		sevstr = "Harmless";
		break;
	case MCE_SEV_WARNING:
		level = KERN_WARNING;
		sevstr = "Warning";
		break;
	case MCE_SEV_SEVERE:
		level = KERN_ERR;
		sevstr = "Severe";
		break;
	case MCE_SEV_FATAL:
	default:
		level = KERN_ERR;
		sevstr = "Fatal";
		break;
	}

	switch(evt->initiator) {
	case MCE_INITIATOR_CPU:
		initiator = "CPU";
		break;
	case MCE_INITIATOR_PCI:
		initiator = "PCI";
		break;
	case MCE_INITIATOR_ISA:
		initiator = "ISA";
		break;
	case MCE_INITIATOR_MEMORY:
		initiator = "Memory";
		break;
	case MCE_INITIATOR_POWERMGM:
		initiator = "Power Management";
		break;
	case MCE_INITIATOR_UNKNOWN:
	default:
		initiator = "Unknown";
		break;
	}

	switch (evt->error_type) {
	case MCE_ERROR_TYPE_UE:
		err_type = "UE";
		subtype = evt->u.ue_error.ue_error_type <
			ARRAY_SIZE(mc_ue_types) ?
			mc_ue_types[evt->u.ue_error.ue_error_type]
			: "Unknown";
		if (evt->u.ue_error.effective_address_provided)
			ea = evt->u.ue_error.effective_address;
		if (evt->u.ue_error.physical_address_provided)
			pa = evt->u.ue_error.physical_address;
		break;
	case MCE_ERROR_TYPE_SLB:
		err_type = "SLB";
		subtype = evt->u.slb_error.slb_error_type <
			ARRAY_SIZE(mc_slb_types) ?
			mc_slb_types[evt->u.slb_error.slb_error_type]
			: "Unknown";
		if (evt->u.slb_error.effective_address_provided)
			ea = evt->u.slb_error.effective_address;
		break;
	case MCE_ERROR_TYPE_ERAT:
		err_type = "ERAT";
		subtype = evt->u.erat_error.erat_error_type <
			ARRAY_SIZE(mc_erat_types) ?
			mc_erat_types[evt->u.erat_error.erat_error_type]
			: "Unknown";
		if (evt->u.erat_error.effective_address_provided)
			ea = evt->u.erat_error.effective_address;
		break;
	case MCE_ERROR_TYPE_TLB:
		err_type = "TLB";
		subtype = evt->u.tlb_error.tlb_error_type <
			ARRAY_SIZE(mc_tlb_types) ?
			mc_tlb_types[evt->u.tlb_error.tlb_error_type]
			: "Unknown";
		if (evt->u.tlb_error.effective_address_provided)
			ea = evt->u.tlb_error.effective_address;
		break;
	case MCE_ERROR_TYPE_USER:
		err_type = "User";
		subtype = evt->u.user_error.user_error_type <
			ARRAY_SIZE(mc_user_types) ?
			mc_user_types[evt->u.user_error.user_error_type]
			: "Unknown";
		if (evt->u.user_error.effective_address_provided)
			ea = evt->u.user_error.effective_address;
		break;
	case MCE_ERROR_TYPE_RA:
		err_type = "Real address";
		subtype = evt->u.ra_error.ra_error_type <
			ARRAY_SIZE(mc_ra_types) ?
			mc_ra_types[evt->u.ra_error.ra_error_type]
			: "Unknown";
		if (evt->u.ra_error.effective_address_provided)
			ea = evt->u.ra_error.effective_address;
		break;
	case MCE_ERROR_TYPE_LINK:
		err_type = "Link";
		subtype = evt->u.link_error.link_error_type <
			ARRAY_SIZE(mc_link_types) ?
			mc_link_types[evt->u.link_error.link_error_type]
			: "Unknown";
		if (evt->u.link_error.effective_address_provided)
			ea = evt->u.link_error.effective_address;
		break;
	case MCE_ERROR_TYPE_DCACHE:
		err_type = "D-Cache";
		subtype = "Unknown";
		break;
	case MCE_ERROR_TYPE_ICACHE:
		err_type = "I-Cache";
		subtype = "Unknown";
		break;
	default:
	case MCE_ERROR_TYPE_UNKNOWN:
		err_type = "Unknown";
		subtype = "";
		break;
	}

	dar_str[0] = pa_str[0] = '\0';
	if (ea && evt->srr0 != ea) {
		/* Load/Store address */
		n = sprintf(dar_str, "DAR: %016llx ", ea);
		if (pa)
			sprintf(dar_str + n, "paddr: %016llx ", pa);
	} else if (pa) {
		sprintf(pa_str, " paddr: %016llx", pa);
	}

	printk("%sMCE: CPU%d: machine check (%s) %s %s %s %s[%s]\n",
		level, evt->cpu, sevstr, in_guest ? "Guest" : "",
		err_type, subtype, dar_str,
		evt->disposition == MCE_DISPOSITION_RECOVERED ?
		"Recovered" : "Not recovered");

	if (in_guest || user_mode) {
		printk("%sMCE: CPU%d: PID: %d Comm: %s %sNIP: [%016llx]%s\n",
			level, evt->cpu, current->pid, current->comm,
			in_guest ? "Guest " : "", evt->srr0, pa_str);
	} else {
		printk("%sMCE: CPU%d: NIP: [%016llx] %pS%s\n",
			level, evt->cpu, evt->srr0, (void *)evt->srr0, pa_str);
	}

	printk("%sMCE: CPU%d: Initiator %s\n", level, evt->cpu, initiator);

	subtype = evt->error_class < ARRAY_SIZE(mc_error_class) ?
		mc_error_class[evt->error_class] : "Unknown";
	printk("%sMCE: CPU%d: %s\n", level, evt->cpu, subtype);

#ifdef CONFIG_PPC_BOOK3S_64
	/* Display faulty slb contents for SLB errors. */
	if (evt->error_type == MCE_ERROR_TYPE_SLB && !in_guest)
		slb_dump_contents(local_paca->mce_faulty_slbs);
#endif
}
EXPORT_SYMBOL_GPL(machine_check_print_event_info);

/*
 * This function is called in real mode. Strictly no printk's please.
 *
 * regs->nip and regs->msr contains srr0 and ssr1.
 */
DEFINE_INTERRUPT_HANDLER_NMI(machine_check_early)
{
	long handled = 0;

	hv_nmi_check_nonrecoverable(regs);

	/*
	 * See if platform is capable of handling machine check.
	 */
	if (ppc_md.machine_check_early)
		handled = ppc_md.machine_check_early(regs);

	return handled;
}

/* Possible meanings for HMER_DEBUG_TRIG bit being set on POWER9 */
static enum {
	DTRIG_UNKNOWN,
	DTRIG_VECTOR_CI,	/* need to emulate vector CI load instr */
	DTRIG_SUSPEND_ESCAPE,	/* need to escape from TM suspend mode */
} hmer_debug_trig_function;

static int init_debug_trig_function(void)
{
	int pvr;
	struct device_node *cpun;
	struct property *prop = NULL;
	const char *str;

	/* First look in the device tree */
	preempt_disable();
	cpun = of_get_cpu_node(smp_processor_id(), NULL);
	if (cpun) {
		of_property_for_each_string(cpun, "ibm,hmi-special-triggers",
					    prop, str) {
			if (strcmp(str, "bit17-vector-ci-load") == 0)
				hmer_debug_trig_function = DTRIG_VECTOR_CI;
			else if (strcmp(str, "bit17-tm-suspend-escape") == 0)
				hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
		}
		of_node_put(cpun);
	}
	preempt_enable();

	/* If we found the property, don't look at PVR */
	if (prop)
		goto out;

	pvr = mfspr(SPRN_PVR);
	/* Check for POWER9 Nimbus (scale-out) */
	if ((PVR_VER(pvr) == PVR_POWER9) && (pvr & 0xe000) == 0) {
		/* DD2.2 and later */
		if ((pvr & 0xfff) >= 0x202)
			hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
		/* DD2.0 and DD2.1 - used for vector CI load emulation */
		else if ((pvr & 0xfff) >= 0x200)
			hmer_debug_trig_function = DTRIG_VECTOR_CI;
	}

 out:
	switch (hmer_debug_trig_function) {
	case DTRIG_VECTOR_CI:
		pr_debug("HMI debug trigger used for vector CI load\n");
		break;
	case DTRIG_SUSPEND_ESCAPE:
		pr_debug("HMI debug trigger used for TM suspend escape\n");
		break;
	default:
		break;
	}
	return 0;
}
__initcall(init_debug_trig_function);

/*
 * Handle HMIs that occur as a result of a debug trigger.
 * Return values:
 * -1 means this is not a HMI cause that we know about
 *  0 means no further handling is required
 *  1 means further handling is required
 */
long hmi_handle_debugtrig(struct pt_regs *regs)
{
	unsigned long hmer = mfspr(SPRN_HMER);
	long ret = 0;

	/* HMER_DEBUG_TRIG bit is used for various workarounds on P9 */
	if (!((hmer & HMER_DEBUG_TRIG)
	      && hmer_debug_trig_function != DTRIG_UNKNOWN))
		return -1;
		
	hmer &= ~HMER_DEBUG_TRIG;
	/* HMER is a write-AND register */
	mtspr(SPRN_HMER, ~HMER_DEBUG_TRIG);

	switch (hmer_debug_trig_function) {
	case DTRIG_VECTOR_CI:
		/*
		 * Now to avoid problems with soft-disable we
		 * only do the emulation if we are coming from
		 * host user space
		 */
		if (regs && user_mode(regs))
			ret = local_paca->hmi_p9_special_emu = 1;

		break;

	default:
		break;
	}

	/*
	 * See if any other HMI causes remain to be handled
	 */
	if (hmer & mfspr(SPRN_HMEER))
		return -1;

	return ret;
}

/*
 * Return values:
 */
DEFINE_INTERRUPT_HANDLER_NMI(hmi_exception_realmode)
{	
	int ret;

	local_paca->hmi_irqs++;

	ret = hmi_handle_debugtrig(regs);
	if (ret >= 0)
		return ret;

	wait_for_subcore_guest_exit();

	if (ppc_md.hmi_exception_early)
		ppc_md.hmi_exception_early(regs);

	wait_for_tb_resync();

	return 1;
}

void __init mce_init(void)
{
	struct mce_info *mce_info;
	u64 limit;
	int i;

	limit = min(ppc64_bolted_size(), ppc64_rma_size);
	for_each_possible_cpu(i) {
		mce_info = memblock_alloc_try_nid(sizeof(*mce_info),
						  __alignof__(*mce_info),
						  MEMBLOCK_LOW_LIMIT,
						  limit, cpu_to_node(i));
		if (!mce_info)
			goto err;
		paca_ptrs[i]->mce_info = mce_info;
	}
	return;
err:
	panic("Failed to allocate memory for MCE event data\n");
}