summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/platforms/pseries/ras.c
blob: c97d15352f9ff086ade22879596607e87f283cb3 (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
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
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
/*
 * Copyright (C) 2001 Dave Engebretsen IBM Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/irq_work.h>

#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/firmware.h>
#include <asm/mce.h>

#include "pseries.h"

static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
static DEFINE_SPINLOCK(ras_log_buf_lock);

static int ras_check_exception_token;

static void mce_process_errlog_event(struct irq_work *work);
static struct irq_work mce_errlog_process_work = {
	.func = mce_process_errlog_event,
};

#define EPOW_SENSOR_TOKEN	9
#define EPOW_SENSOR_INDEX	0

/* EPOW events counter variable */
static int num_epow_events;

static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id);
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
static irqreturn_t ras_error_interrupt(int irq, void *dev_id);

/* RTAS pseries MCE errorlog section. */
struct pseries_mc_errorlog {
	__be32	fru_id;
	__be32	proc_id;
	u8	error_type;
	/*
	 * sub_err_type (1 byte). Bit fields depends on error_type
	 *
	 *   MSB0
	 *   |
	 *   V
	 *   01234567
	 *   XXXXXXXX
	 *
	 * For error_type == MC_ERROR_TYPE_UE
	 *   XXXXXXXX
	 *   X		1: Permanent or Transient UE.
	 *    X		1: Effective address provided.
	 *     X	1: Logical address provided.
	 *      XX	2: Reserved.
	 *        XXX	3: Type of UE error.
	 *
	 * For error_type != MC_ERROR_TYPE_UE
	 *   XXXXXXXX
	 *   X		1: Effective address provided.
	 *    XXXXX	5: Reserved.
	 *         XX	2: Type of SLB/ERAT/TLB error.
	 */
	u8	sub_err_type;
	u8	reserved_1[6];
	__be64	effective_address;
	__be64	logical_address;
} __packed;

/* RTAS pseries MCE error types */
#define MC_ERROR_TYPE_UE		0x00
#define MC_ERROR_TYPE_SLB		0x01
#define MC_ERROR_TYPE_ERAT		0x02
#define MC_ERROR_TYPE_TLB		0x04
#define MC_ERROR_TYPE_D_CACHE		0x05
#define MC_ERROR_TYPE_I_CACHE		0x07

/* RTAS pseries MCE error sub types */
#define MC_ERROR_UE_INDETERMINATE		0
#define MC_ERROR_UE_IFETCH			1
#define MC_ERROR_UE_PAGE_TABLE_WALK_IFETCH	2
#define MC_ERROR_UE_LOAD_STORE			3
#define MC_ERROR_UE_PAGE_TABLE_WALK_LOAD_STORE	4

#define MC_ERROR_SLB_PARITY		0
#define MC_ERROR_SLB_MULTIHIT		1
#define MC_ERROR_SLB_INDETERMINATE	2

#define MC_ERROR_ERAT_PARITY		1
#define MC_ERROR_ERAT_MULTIHIT		2
#define MC_ERROR_ERAT_INDETERMINATE	3

#define MC_ERROR_TLB_PARITY		1
#define MC_ERROR_TLB_MULTIHIT		2
#define MC_ERROR_TLB_INDETERMINATE	3

static inline u8 rtas_mc_error_sub_type(const struct pseries_mc_errorlog *mlog)
{
	switch (mlog->error_type) {
	case	MC_ERROR_TYPE_UE:
		return (mlog->sub_err_type & 0x07);
	case	MC_ERROR_TYPE_SLB:
	case	MC_ERROR_TYPE_ERAT:
	case	MC_ERROR_TYPE_TLB:
		return (mlog->sub_err_type & 0x03);
	default:
		return 0;
	}
}

static
inline u64 rtas_mc_get_effective_addr(const struct pseries_mc_errorlog *mlog)
{
	__be64 addr = 0;

	switch (mlog->error_type) {
	case	MC_ERROR_TYPE_UE:
		if (mlog->sub_err_type & 0x40)
			addr = mlog->effective_address;
		break;
	case	MC_ERROR_TYPE_SLB:
	case	MC_ERROR_TYPE_ERAT:
	case	MC_ERROR_TYPE_TLB:
		if (mlog->sub_err_type & 0x80)
			addr = mlog->effective_address;
	default:
		break;
	}
	return be64_to_cpu(addr);
}

/*
 * Enable the hotplug interrupt late because processing them may touch other
 * devices or systems (e.g. hugepages) that have not been initialized at the
 * subsys stage.
 */
int __init init_ras_hotplug_IRQ(void)
{
	struct device_node *np;

	/* Hotplug Events */
	np = of_find_node_by_path("/event-sources/hot-plug-events");
	if (np != NULL) {
		if (dlpar_workqueue_init() == 0)
			request_event_sources_irqs(np, ras_hotplug_interrupt,
						   "RAS_HOTPLUG");
		of_node_put(np);
	}

	return 0;
}
machine_late_initcall(pseries, init_ras_hotplug_IRQ);

/*
 * Initialize handlers for the set of interrupts caused by hardware errors
 * and power system events.
 */
static int __init init_ras_IRQ(void)
{
	struct device_node *np;

	ras_check_exception_token = rtas_token("check-exception");

	/* Internal Errors */
	np = of_find_node_by_path("/event-sources/internal-errors");
	if (np != NULL) {
		request_event_sources_irqs(np, ras_error_interrupt,
					   "RAS_ERROR");
		of_node_put(np);
	}

	/* EPOW Events */
	np = of_find_node_by_path("/event-sources/epow-events");
	if (np != NULL) {
		request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW");
		of_node_put(np);
	}

	return 0;
}
machine_subsys_initcall(pseries, init_ras_IRQ);

#define EPOW_SHUTDOWN_NORMAL				1
#define EPOW_SHUTDOWN_ON_UPS				2
#define EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS	3
#define EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH	4

static void handle_system_shutdown(char event_modifier)
{
	switch (event_modifier) {
	case EPOW_SHUTDOWN_NORMAL:
		pr_emerg("Power off requested\n");
		orderly_poweroff(true);
		break;

	case EPOW_SHUTDOWN_ON_UPS:
		pr_emerg("Loss of system power detected. System is running on"
			 " UPS/battery. Check RTAS error log for details\n");
		orderly_poweroff(true);
		break;

	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
		pr_emerg("Loss of system critical functions detected. Check"
			 " RTAS error log for details\n");
		orderly_poweroff(true);
		break;

	case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
		pr_emerg("High ambient temperature detected. Check RTAS"
			 " error log for details\n");
		orderly_poweroff(true);
		break;

	default:
		pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
			event_modifier);
	}
}

struct epow_errorlog {
	unsigned char sensor_value;
	unsigned char event_modifier;
	unsigned char extended_modifier;
	unsigned char reserved;
	unsigned char platform_reason;
};

#define EPOW_RESET			0
#define EPOW_WARN_COOLING		1
#define EPOW_WARN_POWER			2
#define EPOW_SYSTEM_SHUTDOWN		3
#define EPOW_SYSTEM_HALT		4
#define EPOW_MAIN_ENCLOSURE		5
#define EPOW_POWER_OFF			7

static void rtas_parse_epow_errlog(struct rtas_error_log *log)
{
	struct pseries_errorlog *pseries_log;
	struct epow_errorlog *epow_log;
	char action_code;
	char modifier;

	pseries_log = get_pseries_errorlog(log, PSERIES_ELOG_SECT_ID_EPOW);
	if (pseries_log == NULL)
		return;

	epow_log = (struct epow_errorlog *)pseries_log->data;
	action_code = epow_log->sensor_value & 0xF;	/* bottom 4 bits */
	modifier = epow_log->event_modifier & 0xF;	/* bottom 4 bits */

	switch (action_code) {
	case EPOW_RESET:
		if (num_epow_events) {
			pr_info("Non critical power/cooling issue cleared\n");
			num_epow_events--;
		}
		break;

	case EPOW_WARN_COOLING:
		pr_info("Non-critical cooling issue detected. Check RTAS error"
			" log for details\n");
		break;

	case EPOW_WARN_POWER:
		pr_info("Non-critical power issue detected. Check RTAS error"
			" log for details\n");
		break;

	case EPOW_SYSTEM_SHUTDOWN:
		handle_system_shutdown(epow_log->event_modifier);
		break;

	case EPOW_SYSTEM_HALT:
		pr_emerg("Critical power/cooling issue detected. Check RTAS"
			 " error log for details. Powering off.\n");
		orderly_poweroff(true);
		break;

	case EPOW_MAIN_ENCLOSURE:
	case EPOW_POWER_OFF:
		pr_emerg("System about to lose power. Check RTAS error log "
			 " for details. Powering off immediately.\n");
		emergency_sync();
		kernel_power_off();
		break;

	default:
		pr_err("Unknown power/cooling event (action code  = %d)\n",
			action_code);
	}

	/* Increment epow events counter variable */
	if (action_code != EPOW_RESET)
		num_epow_events++;
}

static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id)
{
	struct pseries_errorlog *pseries_log;
	struct pseries_hp_errorlog *hp_elog;

	spin_lock(&ras_log_buf_lock);

	rtas_call(ras_check_exception_token, 6, 1, NULL,
		  RTAS_VECTOR_EXTERNAL_INTERRUPT, virq_to_hw(irq),
		  RTAS_HOTPLUG_EVENTS, 0, __pa(&ras_log_buf),
		  rtas_get_error_log_max());

	pseries_log = get_pseries_errorlog((struct rtas_error_log *)ras_log_buf,
					   PSERIES_ELOG_SECT_ID_HOTPLUG);
	hp_elog = (struct pseries_hp_errorlog *)pseries_log->data;

	/*
	 * Since PCI hotplug is not currently supported on pseries, put PCI
	 * hotplug events on the ras_log_buf to be handled by rtas_errd.
	 */
	if (hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_MEM ||
	    hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_CPU ||
	    hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_PMEM)
		queue_hotplug_event(hp_elog);
	else
		log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);

	spin_unlock(&ras_log_buf_lock);
	return IRQ_HANDLED;
}

/* Handle environmental and power warning (EPOW) interrupts. */
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
{
	int status;
	int state;
	int critical;

	status = rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX,
				      &state);

	if (state > 3)
		critical = 1;		/* Time Critical */
	else
		critical = 0;

	spin_lock(&ras_log_buf_lock);

	status = rtas_call(ras_check_exception_token, 6, 1, NULL,
			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
			   virq_to_hw(irq),
			   RTAS_EPOW_WARNING,
			   critical, __pa(&ras_log_buf),
				rtas_get_error_log_max());

	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);

	rtas_parse_epow_errlog((struct rtas_error_log *)ras_log_buf);

	spin_unlock(&ras_log_buf_lock);
	return IRQ_HANDLED;
}

/*
 * Handle hardware error interrupts.
 *
 * RTAS check-exception is called to collect data on the exception.  If
 * the error is deemed recoverable, we log a warning and return.
 * For nonrecoverable errors, an error is logged and we stop all processing
 * as quickly as possible in order to prevent propagation of the failure.
 */
static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
{
	struct rtas_error_log *rtas_elog;
	int status;
	int fatal;

	spin_lock(&ras_log_buf_lock);

	status = rtas_call(ras_check_exception_token, 6, 1, NULL,
			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
			   virq_to_hw(irq),
			   RTAS_INTERNAL_ERROR, 1 /* Time Critical */,
			   __pa(&ras_log_buf),
				rtas_get_error_log_max());

	rtas_elog = (struct rtas_error_log *)ras_log_buf;

	if (status == 0 &&
	    rtas_error_severity(rtas_elog) >= RTAS_SEVERITY_ERROR_SYNC)
		fatal = 1;
	else
		fatal = 0;

	/* format and print the extended information */
	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);

	if (fatal) {
		pr_emerg("Fatal hardware error detected. Check RTAS error"
			 " log for details. Powering off immediately\n");
		emergency_sync();
		kernel_power_off();
	} else {
		pr_err("Recoverable hardware error detected\n");
	}

	spin_unlock(&ras_log_buf_lock);
	return IRQ_HANDLED;
}

/*
 * Some versions of FWNMI place the buffer inside the 4kB page starting at
 * 0x7000. Other versions place it inside the rtas buffer. We check both.
 */
#define VALID_FWNMI_BUFFER(A) \
	((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
	(((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))

static inline struct rtas_error_log *fwnmi_get_errlog(void)
{
	return (struct rtas_error_log *)local_paca->mce_data_buf;
}

/*
 * Get the error information for errors coming through the
 * FWNMI vectors.  The pt_regs' r3 will be updated to reflect
 * the actual r3 if possible, and a ptr to the error log entry
 * will be returned if found.
 *
 * Use one buffer mce_data_buf per cpu to store RTAS error.
 *
 * The mce_data_buf does not have any locks or protection around it,
 * if a second machine check comes in, or a system reset is done
 * before we have logged the error, then we will get corruption in the
 * error log.  This is preferable over holding off on calling
 * ibm,nmi-interlock which would result in us checkstopping if a
 * second machine check did come in.
 */
static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
{
	unsigned long *savep;
	struct rtas_error_log *h;

	/* Mask top two bits */
	regs->gpr[3] &= ~(0x3UL << 62);

	if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
		printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
		return NULL;
	}

	savep = __va(regs->gpr[3]);
	regs->gpr[3] = be64_to_cpu(savep[0]);	/* restore original r3 */

	h = (struct rtas_error_log *)&savep[1];
	/* Use the per cpu buffer from paca to store rtas error log */
	memset(local_paca->mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
	if (!rtas_error_extended(h)) {
		memcpy(local_paca->mce_data_buf, h, sizeof(__u64));
	} else {
		int len, error_log_length;

		error_log_length = 8 + rtas_error_extended_log_length(h);
		len = min_t(int, error_log_length, RTAS_ERROR_LOG_MAX);
		memcpy(local_paca->mce_data_buf, h, len);
	}

	return (struct rtas_error_log *)local_paca->mce_data_buf;
}

/* Call this when done with the data returned by FWNMI_get_errinfo.
 * It will release the saved data area for other CPUs in the
 * partition to receive FWNMI errors.
 */
static void fwnmi_release_errinfo(void)
{
	int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
	if (ret != 0)
		printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
}

int pSeries_system_reset_exception(struct pt_regs *regs)
{
#ifdef __LITTLE_ENDIAN__
	/*
	 * Some firmware byteswaps SRR registers and gives incorrect SRR1. Try
	 * to detect the bad SRR1 pattern here. Flip the NIP back to correct
	 * endian for reporting purposes. Unfortunately the MSR can't be fixed,
	 * so clear it. It will be missing MSR_RI so we won't try to recover.
	 */
	if ((be64_to_cpu(regs->msr) &
			(MSR_LE|MSR_RI|MSR_DR|MSR_IR|MSR_ME|MSR_PR|
			 MSR_ILE|MSR_HV|MSR_SF)) == (MSR_DR|MSR_SF)) {
		regs->nip = be64_to_cpu((__be64)regs->nip);
		regs->msr = 0;
	}
#endif

	if (fwnmi_active) {
		struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
		if (errhdr) {
			/* XXX Should look at FWNMI information */
		}
		fwnmi_release_errinfo();
	}

	if (smp_handle_nmi_ipi(regs))
		return 1;

	return 0; /* need to perform reset */
}

#define VAL_TO_STRING(ar, val)	\
	(((val) < ARRAY_SIZE(ar)) ? ar[(val)] : "Unknown")

static void pseries_print_mce_info(struct pt_regs *regs,
				   struct rtas_error_log *errp)
{
	const char *level, *sevstr;
	struct pseries_errorlog *pseries_log;
	struct pseries_mc_errorlog *mce_log;
	u8 error_type, err_sub_type;
	u64 addr;
	u8 initiator = rtas_error_initiator(errp);
	int disposition = rtas_error_disposition(errp);

	static const char * const initiators[] = {
		[0] = "Unknown",
		[1] = "CPU",
		[2] = "PCI",
		[3] = "ISA",
		[4] = "Memory",
		[5] = "Power Mgmt",
	};
	static const char * const mc_err_types[] = {
		[0] = "UE",
		[1] = "SLB",
		[2] = "ERAT",
		[3] = "Unknown",
		[4] = "TLB",
		[5] = "D-Cache",
		[6] = "Unknown",
		[7] = "I-Cache",
	};
	static const char * const mc_ue_types[] = {
		[0] = "Indeterminate",
		[1] = "Instruction fetch",
		[2] = "Page table walk ifetch",
		[3] = "Load/Store",
		[4] = "Page table walk Load/Store",
	};

	/* SLB sub errors valid values are 0x0, 0x1, 0x2 */
	static const char * const mc_slb_types[] = {
		[0] = "Parity",
		[1] = "Multihit",
		[2] = "Indeterminate",
	};

	/* TLB and ERAT sub errors valid values are 0x1, 0x2, 0x3 */
	static const char * const mc_soft_types[] = {
		[0] = "Unknown",
		[1] = "Parity",
		[2] = "Multihit",
		[3] = "Indeterminate",
	};

	if (!rtas_error_extended(errp)) {
		pr_err("Machine check interrupt: Missing extended error log\n");
		return;
	}

	pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
	if (pseries_log == NULL)
		return;

	mce_log = (struct pseries_mc_errorlog *)pseries_log->data;

	error_type = mce_log->error_type;
	err_sub_type = rtas_mc_error_sub_type(mce_log);

	switch (rtas_error_severity(errp)) {
	case RTAS_SEVERITY_NO_ERROR:
		level = KERN_INFO;
		sevstr = "Harmless";
		break;
	case RTAS_SEVERITY_WARNING:
		level = KERN_WARNING;
		sevstr = "";
		break;
	case RTAS_SEVERITY_ERROR:
	case RTAS_SEVERITY_ERROR_SYNC:
		level = KERN_ERR;
		sevstr = "Severe";
		break;
	case RTAS_SEVERITY_FATAL:
	default:
		level = KERN_ERR;
		sevstr = "Fatal";
		break;
	}

#ifdef CONFIG_PPC_BOOK3S_64
	/* Display faulty slb contents for SLB errors. */
	if (error_type == MC_ERROR_TYPE_SLB)
		slb_dump_contents(local_paca->mce_faulty_slbs);
#endif

	printk("%s%s Machine check interrupt [%s]\n", level, sevstr,
	       disposition == RTAS_DISP_FULLY_RECOVERED ?
	       "Recovered" : "Not recovered");
	if (user_mode(regs)) {
		printk("%s  NIP: [%016lx] PID: %d Comm: %s\n", level,
		       regs->nip, current->pid, current->comm);
	} else {
		printk("%s  NIP [%016lx]: %pS\n", level, regs->nip,
		       (void *)regs->nip);
	}
	printk("%s  Initiator: %s\n", level,
	       VAL_TO_STRING(initiators, initiator));

	switch (error_type) {
	case MC_ERROR_TYPE_UE:
		printk("%s  Error type: %s [%s]\n", level,
		       VAL_TO_STRING(mc_err_types, error_type),
		       VAL_TO_STRING(mc_ue_types, err_sub_type));
		break;
	case MC_ERROR_TYPE_SLB:
		printk("%s  Error type: %s [%s]\n", level,
		       VAL_TO_STRING(mc_err_types, error_type),
		       VAL_TO_STRING(mc_slb_types, err_sub_type));
		break;
	case MC_ERROR_TYPE_ERAT:
	case MC_ERROR_TYPE_TLB:
		printk("%s  Error type: %s [%s]\n", level,
		       VAL_TO_STRING(mc_err_types, error_type),
		       VAL_TO_STRING(mc_soft_types, err_sub_type));
		break;
	default:
		printk("%s  Error type: %s\n", level,
		       VAL_TO_STRING(mc_err_types, error_type));
		break;
	}

	addr = rtas_mc_get_effective_addr(mce_log);
	if (addr)
		printk("%s    Effective address: %016llx\n", level, addr);
}

static int mce_handle_error(struct rtas_error_log *errp)
{
	struct pseries_errorlog *pseries_log;
	struct pseries_mc_errorlog *mce_log;
	int disposition = rtas_error_disposition(errp);
	u8 error_type;

	if (!rtas_error_extended(errp))
		goto out;

	pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
	if (pseries_log == NULL)
		goto out;

	mce_log = (struct pseries_mc_errorlog *)pseries_log->data;
	error_type = mce_log->error_type;

#ifdef CONFIG_PPC_BOOK3S_64
	if (disposition == RTAS_DISP_NOT_RECOVERED) {
		switch (error_type) {
		case	MC_ERROR_TYPE_SLB:
		case	MC_ERROR_TYPE_ERAT:
			/*
			 * Store the old slb content in paca before flushing.
			 * Print this when we go to virtual mode.
			 * There are chances that we may hit MCE again if there
			 * is a parity error on the SLB entry we trying to read
			 * for saving. Hence limit the slb saving to single
			 * level of recursion.
			 */
			if (local_paca->in_mce == 1)
				slb_save_contents(local_paca->mce_faulty_slbs);
			flush_and_reload_slb();
			disposition = RTAS_DISP_FULLY_RECOVERED;
			rtas_set_disposition_recovered(errp);
			break;
		default:
			break;
		}
	}
#endif

out:
	return disposition;
}

#ifdef CONFIG_MEMORY_FAILURE

static DEFINE_PER_CPU(int, rtas_ue_count);
static DEFINE_PER_CPU(unsigned long, rtas_ue_paddr[MAX_MC_EVT]);

#define UE_EFFECTIVE_ADDR_PROVIDED	0x40
#define UE_LOGICAL_ADDR_PROVIDED	0x20


static void pseries_hwpoison_work_fn(struct work_struct *work)
{
	unsigned long paddr;
	int index;

	while (__this_cpu_read(rtas_ue_count) > 0) {
		index = __this_cpu_read(rtas_ue_count) - 1;
		paddr = __this_cpu_read(rtas_ue_paddr[index]);
		memory_failure(paddr >> PAGE_SHIFT, 0);
		__this_cpu_dec(rtas_ue_count);
	}
}

static DECLARE_WORK(hwpoison_work, pseries_hwpoison_work_fn);

static void queue_ue_paddr(unsigned long paddr)
{
	int index;

	index = __this_cpu_inc_return(rtas_ue_count) - 1;
	if (index >= MAX_MC_EVT) {
		__this_cpu_dec(rtas_ue_count);
		return;
	}
	this_cpu_write(rtas_ue_paddr[index], paddr);
	schedule_work(&hwpoison_work);
}

static void pseries_do_memory_failure(struct pt_regs *regs,
				      struct pseries_mc_errorlog *mce_log)
{
	unsigned long paddr;

	if (mce_log->sub_err_type & UE_LOGICAL_ADDR_PROVIDED) {
		paddr = be64_to_cpu(mce_log->logical_address);
	} else if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED) {
		unsigned long pfn;

		pfn = addr_to_pfn(regs,
				  be64_to_cpu(mce_log->effective_address));
		if (pfn == ULONG_MAX)
			return;
		paddr = pfn << PAGE_SHIFT;
	} else {
		return;
	}
	queue_ue_paddr(paddr);
}

static void pseries_process_ue(struct pt_regs *regs,
			       struct rtas_error_log *errp)
{
	struct pseries_errorlog *pseries_log;
	struct pseries_mc_errorlog *mce_log;

	if (!rtas_error_extended(errp))
		return;

	pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
	if (!pseries_log)
		return;

	mce_log = (struct pseries_mc_errorlog *)pseries_log->data;

	if (mce_log->error_type == MC_ERROR_TYPE_UE)
		pseries_do_memory_failure(regs, mce_log);
}
#else
static inline void pseries_process_ue(struct pt_regs *regs,
				      struct rtas_error_log *errp) { }
#endif /*CONFIG_MEMORY_FAILURE */

/*
 * Process MCE rtas errlog event.
 */
static void mce_process_errlog_event(struct irq_work *work)
{
	struct rtas_error_log *err;

	err = fwnmi_get_errlog();
	log_error((char *)err, ERR_TYPE_RTAS_LOG, 0);
}

/*
 * See if we can recover from a machine check exception.
 * This is only called on power4 (or above) and only via
 * the Firmware Non-Maskable Interrupts (fwnmi) handler
 * which provides the error analysis for us.
 *
 * Return 1 if corrected (or delivered a signal).
 * Return 0 if there is nothing we can do.
 */
static int recover_mce(struct pt_regs *regs, struct rtas_error_log *err)
{
	int recovered = 0;
	int disposition = rtas_error_disposition(err);

	pseries_print_mce_info(regs, err);

	if (!(regs->msr & MSR_RI)) {
		/* If MSR_RI isn't set, we cannot recover */
		pr_err("Machine check interrupt unrecoverable: MSR(RI=0)\n");
		recovered = 0;

	} else if (disposition == RTAS_DISP_FULLY_RECOVERED) {
		/* Platform corrected itself */
		recovered = 1;

	} else if (disposition == RTAS_DISP_LIMITED_RECOVERY) {
		/* Platform corrected itself but could be degraded */
		printk(KERN_ERR "MCE: limited recovery, system may "
		       "be degraded\n");
		recovered = 1;

	} else if (user_mode(regs) && !is_global_init(current) &&
		   rtas_error_severity(err) == RTAS_SEVERITY_ERROR_SYNC) {

		/*
		 * If we received a synchronous error when in userspace
		 * kill the task. Firmware may report details of the fail
		 * asynchronously, so we can't rely on the target and type
		 * fields being valid here.
		 */
		printk(KERN_ERR "MCE: uncorrectable error, killing task "
		       "%s:%d\n", current->comm, current->pid);

		_exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip);
		recovered = 1;
	}

	pseries_process_ue(regs, err);

	/* Queue irq work to log this rtas event later. */
	irq_work_queue(&mce_errlog_process_work);

	return recovered;
}

/*
 * Handle a machine check.
 *
 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
 * should be present.  If so the handler which called us tells us if the
 * error was recovered (never true if RI=0).
 *
 * On hardware prior to Power 4 these exceptions were asynchronous which
 * means we can't tell exactly where it occurred and so we can't recover.
 */
int pSeries_machine_check_exception(struct pt_regs *regs)
{
	struct rtas_error_log *errp;

	if (fwnmi_active) {
		fwnmi_release_errinfo();
		errp = fwnmi_get_errlog();
		if (errp && recover_mce(regs, errp))
			return 1;
	}

	return 0;
}

long pseries_machine_check_realmode(struct pt_regs *regs)
{
	struct rtas_error_log *errp;
	int disposition;

	if (fwnmi_active) {
		errp = fwnmi_get_errinfo(regs);
		/*
		 * Call to fwnmi_release_errinfo() in real mode causes kernel
		 * to panic. Hence we will call it as soon as we go into
		 * virtual mode.
		 */
		disposition = mce_handle_error(errp);
		if (disposition == RTAS_DISP_FULLY_RECOVERED)
			return 1;
	}

	return 0;
}