summaryrefslogtreecommitdiff
path: root/arch/ia64/kernel/mca_drv.c
blob: 832cf1e647e821f8543b8682b8675c95accc9828 (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
/*
 * File:	mca_drv.c
 * Purpose:	Generic MCA handling layer
 *
 * Copyright (C) 2004 FUJITSU LIMITED
 * Copyright (C) Hidetoshi Seto (seto.hidetoshi@jp.fujitsu.com)
 * Copyright (C) 2005 Silicon Graphics, Inc
 * Copyright (C) 2005 Keith Owens <kaos@sgi.com>
 * Copyright (C) 2006 Russ Anderson <rja@sgi.com>
 */
#include <linux/types.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kallsyms.h>
#include <linux/smp_lock.h>
#include <linux/bootmem.h>
#include <linux/acpi.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/workqueue.h>
#include <linux/mm.h>

#include <asm/delay.h>
#include <asm/machvec.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/system.h>
#include <asm/sal.h>
#include <asm/mca.h>

#include <asm/irq.h>
#include <asm/hw_irq.h>

#include "mca_drv.h"

/* max size of SAL error record (default) */
static int sal_rec_max = 10000;

/* from mca_drv_asm.S */
extern void *mca_handler_bhhook(void);

static DEFINE_SPINLOCK(mca_bh_lock);

typedef enum {
	MCA_IS_LOCAL  = 0,
	MCA_IS_GLOBAL = 1
} mca_type_t;

#define MAX_PAGE_ISOLATE 1024

static struct page *page_isolate[MAX_PAGE_ISOLATE];
static int num_page_isolate = 0;

typedef enum {
	ISOLATE_NG,
	ISOLATE_OK,
	ISOLATE_NONE
} isolate_status_t;

typedef enum {
	MCA_NOT_RECOVERED = 0,
	MCA_RECOVERED	  = 1
} recovery_status_t;

/*
 *  This pool keeps pointers to the section part of SAL error record
 */
static struct {
	slidx_list_t *buffer; /* section pointer list pool */
	int	     cur_idx; /* Current index of section pointer list pool */
	int	     max_idx; /* Maximum index of section pointer list pool */
} slidx_pool;

static int
fatal_mca(const char *fmt, ...)
{
	va_list args;
	char buf[256];

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	ia64_mca_printk(KERN_ALERT "MCA: %s\n", buf);

	return MCA_NOT_RECOVERED;
}

static int
mca_recovered(const char *fmt, ...)
{
	va_list args;
	char buf[256];

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	ia64_mca_printk(KERN_INFO "MCA: %s\n", buf);

	return MCA_RECOVERED;
}

/**
 * mca_page_isolate - isolate a poisoned page in order not to use it later
 * @paddr:	poisoned memory location
 *
 * Return value:
 *	one of isolate_status_t, ISOLATE_OK/NG/NONE.
 */

static isolate_status_t
mca_page_isolate(unsigned long paddr)
{
	int i;
	struct page *p;

	/* whether physical address is valid or not */
	if (!ia64_phys_addr_valid(paddr))
		return ISOLATE_NONE;

	if (!pfn_valid(paddr >> PAGE_SHIFT))
		return ISOLATE_NONE;

	/* convert physical address to physical page number */
	p = pfn_to_page(paddr>>PAGE_SHIFT);

	/* check whether a page number have been already registered or not */
	for (i = 0; i < num_page_isolate; i++)
		if (page_isolate[i] == p)
			return ISOLATE_OK; /* already listed */

	/* limitation check */
	if (num_page_isolate == MAX_PAGE_ISOLATE)
		return ISOLATE_NG;

	/* kick pages having attribute 'SLAB' or 'Reserved' */
	if (PageSlab(p) || PageReserved(p))
		return ISOLATE_NG;

	/* add attribute 'Reserved' and register the page */
	get_page(p);
	SetPageReserved(p);
	page_isolate[num_page_isolate++] = p;

	return ISOLATE_OK;
}

/**
 * mca_hanlder_bh - Kill the process which occurred memory read error
 * @paddr:	poisoned address received from MCA Handler
 */

void
mca_handler_bh(unsigned long paddr, void *iip, unsigned long ipsr)
{
	ia64_mlogbuf_dump();
	printk(KERN_ERR "OS_MCA: process [cpu %d, pid: %d, uid: %d, "
		"iip: %p, psr: 0x%lx,paddr: 0x%lx](%s) encounters MCA.\n",
		raw_smp_processor_id(), current->pid, current->uid,
		iip, ipsr, paddr, current->comm);

	spin_lock(&mca_bh_lock);
	switch (mca_page_isolate(paddr)) {
	case ISOLATE_OK:
		printk(KERN_DEBUG "Page isolation: ( %lx ) success.\n", paddr);
		break;
	case ISOLATE_NG:
		printk(KERN_CRIT "Page isolation: ( %lx ) failure.\n", paddr);
		break;
	default:
		break;
	}
	spin_unlock(&mca_bh_lock);

	/* This process is about to be killed itself */
	do_exit(SIGKILL);
}

/**
 * mca_make_peidx - Make index of processor error section
 * @slpi:	pointer to record of processor error section
 * @peidx:	pointer to index of processor error section
 */

static void
mca_make_peidx(sal_log_processor_info_t *slpi, peidx_table_t *peidx)
{
	/*
	 * calculate the start address of
	 *   "struct cpuid_info" and "sal_processor_static_info_t".
	 */
	u64 total_check_num = slpi->valid.num_cache_check
				+ slpi->valid.num_tlb_check
				+ slpi->valid.num_bus_check
				+ slpi->valid.num_reg_file_check
				+ slpi->valid.num_ms_check;
	u64 head_size =	sizeof(sal_log_mod_error_info_t) * total_check_num
			+ sizeof(sal_log_processor_info_t);
	u64 mid_size  = slpi->valid.cpuid_info * sizeof(struct sal_cpuid_info);

	peidx_head(peidx)   = slpi;
	peidx_mid(peidx)    = (struct sal_cpuid_info *)
		(slpi->valid.cpuid_info ? ((char*)slpi + head_size) : NULL);
	peidx_bottom(peidx) = (sal_processor_static_info_t *)
		(slpi->valid.psi_static_struct ?
			((char*)slpi + head_size + mid_size) : NULL);
}

/**
 * mca_make_slidx -  Make index of SAL error record
 * @buffer:	pointer to SAL error record
 * @slidx:	pointer to index of SAL error record
 *
 * Return value:
 *	1 if record has platform error / 0 if not
 */
#define LOG_INDEX_ADD_SECT_PTR(sect, ptr) \
	{slidx_list_t *hl = &slidx_pool.buffer[slidx_pool.cur_idx]; \
	hl->hdr = ptr; \
	list_add(&hl->list, &(sect)); \
	slidx_pool.cur_idx = (slidx_pool.cur_idx + 1)%slidx_pool.max_idx; }

static int
mca_make_slidx(void *buffer, slidx_table_t *slidx)
{
	int platform_err = 0;
	int record_len = ((sal_log_record_header_t*)buffer)->len;
	u32 ercd_pos;
	int sects;
	sal_log_section_hdr_t *sp;

	/*
	 * Initialize index referring current record
	 */
	INIT_LIST_HEAD(&(slidx->proc_err));
	INIT_LIST_HEAD(&(slidx->mem_dev_err));
	INIT_LIST_HEAD(&(slidx->sel_dev_err));
	INIT_LIST_HEAD(&(slidx->pci_bus_err));
	INIT_LIST_HEAD(&(slidx->smbios_dev_err));
	INIT_LIST_HEAD(&(slidx->pci_comp_err));
	INIT_LIST_HEAD(&(slidx->plat_specific_err));
	INIT_LIST_HEAD(&(slidx->host_ctlr_err));
	INIT_LIST_HEAD(&(slidx->plat_bus_err));
	INIT_LIST_HEAD(&(slidx->unsupported));

	/*
	 * Extract a Record Header
	 */
	slidx->header = buffer;

	/*
	 * Extract each section records
	 * (arranged from "int ia64_log_platform_info_print()")
	 */
	for (ercd_pos = sizeof(sal_log_record_header_t), sects = 0;
		ercd_pos < record_len; ercd_pos += sp->len, sects++) {
		sp = (sal_log_section_hdr_t *)((char*)buffer + ercd_pos);
		if (!efi_guidcmp(sp->guid, SAL_PROC_DEV_ERR_SECT_GUID)) {
			LOG_INDEX_ADD_SECT_PTR(slidx->proc_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_MEM_DEV_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->mem_dev_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_SEL_DEV_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->sel_dev_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_PCI_BUS_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->pci_bus_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_SMBIOS_DEV_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->smbios_dev_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_PCI_COMP_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->pci_comp_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_SPECIFIC_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->plat_specific_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_HOST_CTLR_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->host_ctlr_err, sp);
		} else if (!efi_guidcmp(sp->guid,
				SAL_PLAT_BUS_ERR_SECT_GUID)) {
			platform_err = 1;
			LOG_INDEX_ADD_SECT_PTR(slidx->plat_bus_err, sp);
		} else {
			LOG_INDEX_ADD_SECT_PTR(slidx->unsupported, sp);
		}
	}
	slidx->n_sections = sects;

	return platform_err;
}

/**
 * init_record_index_pools - Initialize pool of lists for SAL record index
 *
 * Return value:
 *	0 on Success / -ENOMEM on Failure
 */
static int
init_record_index_pools(void)
{
	int i;
	int rec_max_size;  /* Maximum size of SAL error records */
	int sect_min_size; /* Minimum size of SAL error sections */
	/* minimum size table of each section */
	static int sal_log_sect_min_sizes[] = {
		sizeof(sal_log_processor_info_t)
		+ sizeof(sal_processor_static_info_t),
		sizeof(sal_log_mem_dev_err_info_t),
		sizeof(sal_log_sel_dev_err_info_t),
		sizeof(sal_log_pci_bus_err_info_t),
		sizeof(sal_log_smbios_dev_err_info_t),
		sizeof(sal_log_pci_comp_err_info_t),
		sizeof(sal_log_plat_specific_err_info_t),
		sizeof(sal_log_host_ctlr_err_info_t),
		sizeof(sal_log_plat_bus_err_info_t),
	};

	/*
	 * MCA handler cannot allocate new memory on flight,
	 * so we preallocate enough memory to handle a SAL record.
	 *
	 * Initialize a handling set of slidx_pool:
	 *   1. Pick up the max size of SAL error records
	 *   2. Pick up the min size of SAL error sections
	 *   3. Allocate the pool as enough to 2 SAL records
	 *     (now we can estimate the maxinum of section in a record.)
	 */

	/* - 1 - */
	rec_max_size = sal_rec_max;

	/* - 2 - */
	sect_min_size = sal_log_sect_min_sizes[0];
	for (i = 1; i < sizeof sal_log_sect_min_sizes/sizeof(size_t); i++)
		if (sect_min_size > sal_log_sect_min_sizes[i])
			sect_min_size = sal_log_sect_min_sizes[i];

	/* - 3 - */
	slidx_pool.max_idx = (rec_max_size/sect_min_size) * 2 + 1;
	slidx_pool.buffer = (slidx_list_t *)
		kmalloc(slidx_pool.max_idx * sizeof(slidx_list_t), GFP_KERNEL);

	return slidx_pool.buffer ? 0 : -ENOMEM;
}


/*****************************************************************************
 * Recovery functions                                                        *
 *****************************************************************************/

/**
 * is_mca_global - Check whether this MCA is global or not
 * @peidx:	pointer of index of processor error section
 * @pbci:	pointer to pal_bus_check_info_t
 * @sos:	pointer to hand off struct between SAL and OS
 *
 * Return value:
 *	MCA_IS_LOCAL / MCA_IS_GLOBAL
 */

static mca_type_t
is_mca_global(peidx_table_t *peidx, pal_bus_check_info_t *pbci,
	      struct ia64_sal_os_state *sos)
{
	pal_processor_state_info_t *psp =
		(pal_processor_state_info_t*)peidx_psp(peidx);

	/*
	 * PAL can request a rendezvous, if the MCA has a global scope.
	 * If "rz_always" flag is set, SAL requests MCA rendezvous
	 * in spite of global MCA.
	 * Therefore it is local MCA when rendezvous has not been requested.
	 * Failed to rendezvous, the system must be down.
	 */
	switch (sos->rv_rc) {
		case -1: /* SAL rendezvous unsuccessful */
			return MCA_IS_GLOBAL;
		case  0: /* SAL rendezvous not required */
			return MCA_IS_LOCAL;
		case  1: /* SAL rendezvous successful int */
		case  2: /* SAL rendezvous successful int with init */
		default:
			break;
	}

	/*
	 * If One or more Cache/TLB/Reg_File/Uarch_Check is here,
	 * it would be a local MCA. (i.e. processor internal error)
	 */
	if (psp->tc || psp->cc || psp->rc || psp->uc)
		return MCA_IS_LOCAL;
	
	/*
	 * Bus_Check structure with Bus_Check.ib (internal bus error) flag set
	 * would be a global MCA. (e.g. a system bus address parity error)
	 */
	if (!pbci || pbci->ib)
		return MCA_IS_GLOBAL;

	/*
	 * Bus_Check structure with Bus_Check.eb (external bus error) flag set
	 * could be either a local MCA or a global MCA.
	 *
	 * Referring Bus_Check.bsi:
	 *   0: Unknown/unclassified
	 *   1: BERR#
	 *   2: BINIT#
	 *   3: Hard Fail
	 * (FIXME: Are these SGI specific or generic bsi values?)
	 */
	if (pbci->eb)
		switch (pbci->bsi) {
			case 0:
				/* e.g. a load from poisoned memory */
				return MCA_IS_LOCAL;
			case 1:
			case 2:
			case 3:
				return MCA_IS_GLOBAL;
		}

	return MCA_IS_GLOBAL;
}

/**
 * get_target_identifier - Get the valid Cache or Bus check target identifier.
 * @peidx:	pointer of index of processor error section
 *
 * Return value:
 *	target address on Success / 0 on Failue
 */
static u64
get_target_identifier(peidx_table_t *peidx)
{
	u64 target_address = 0;
	sal_log_mod_error_info_t *smei;
	pal_cache_check_info_t *pcci;
	int i, level = 9;

	/*
	 * Look through the cache checks for a valid target identifier
	 * If more than one valid target identifier, return the one
	 * with the lowest cache level.
	 */
	for (i = 0; i < peidx_cache_check_num(peidx); i++) {
		smei = (sal_log_mod_error_info_t *)peidx_cache_check(peidx, i);
		if (smei->valid.target_identifier && smei->target_identifier) {
			pcci = (pal_cache_check_info_t *)&(smei->check_info);
			if (!target_address || (pcci->level < level)) {
				target_address = smei->target_identifier;
				level = pcci->level;
				continue;
			}
		}
	}
	if (target_address)
		return target_address;

	/*
	 * Look at the bus check for a valid target identifier
	 */
	smei = peidx_bus_check(peidx, 0);
	if (smei && smei->valid.target_identifier)
		return smei->target_identifier;

	return 0;
}

/**
 * recover_from_read_error - Try to recover the errors which type are "read"s.
 * @slidx:	pointer of index of SAL error record
 * @peidx:	pointer of index of processor error section
 * @pbci:	pointer of pal_bus_check_info
 * @sos:	pointer to hand off struct between SAL and OS
 *
 * Return value:
 *	1 on Success / 0 on Failure
 */

static int
recover_from_read_error(slidx_table_t *slidx,
			peidx_table_t *peidx, pal_bus_check_info_t *pbci,
			struct ia64_sal_os_state *sos)
{
	u64 target_identifier;
	pal_min_state_area_t *pmsa;
	struct ia64_psr *psr1, *psr2;
	ia64_fptr_t *mca_hdlr_bh = (ia64_fptr_t*)mca_handler_bhhook;

	/* Is target address valid? */
	target_identifier = get_target_identifier(peidx);
	if (!target_identifier)
		return fatal_mca("target address not valid");

	/*
	 * cpu read or memory-mapped io read
	 *
	 *    offending process  affected process  OS MCA do
	 *     kernel mode        kernel mode       down system
	 *     kernel mode        user   mode       kill the process
	 *     user   mode        kernel mode       down system (*)
	 *     user   mode        user   mode       kill the process
	 *
	 * (*) You could terminate offending user-mode process
	 *    if (pbci->pv && pbci->pl != 0) *and* if you sure
	 *    the process not have any locks of kernel.
	 */

	/* Is minstate valid? */
	if (!peidx_bottom(peidx) || !(peidx_bottom(peidx)->valid.minstate))
		return fatal_mca("minstate not valid");
	psr1 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_ipsr);
	psr2 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_xpsr);

	/*
	 *  Check the privilege level of interrupted context.
	 *   If it is user-mode, then terminate affected process.
	 */

	pmsa = sos->pal_min_state;
	if (psr1->cpl != 0 ||
	   ((psr2->cpl != 0) && mca_recover_range(pmsa->pmsa_iip))) {
		/*
		 *  setup for resume to bottom half of MCA,
		 * "mca_handler_bhhook"
		 */
		/* pass to bhhook as argument (gr8, ...) */
		pmsa->pmsa_gr[8-1] = target_identifier;
		pmsa->pmsa_gr[9-1] = pmsa->pmsa_iip;
		pmsa->pmsa_gr[10-1] = pmsa->pmsa_ipsr;
		/* set interrupted return address (but no use) */
		pmsa->pmsa_br0 = pmsa->pmsa_iip;
		/* change resume address to bottom half */
		pmsa->pmsa_iip = mca_hdlr_bh->fp;
		pmsa->pmsa_gr[1-1] = mca_hdlr_bh->gp;
		/* set cpl with kernel mode */
		psr2 = (struct ia64_psr *)&pmsa->pmsa_ipsr;
		psr2->cpl = 0;
		psr2->ri  = 0;
		psr2->bn  = 1;
		psr2->i  = 0;

		return mca_recovered("user memory corruption. "
				"kill affected process - recovered.");
	}

	return fatal_mca("kernel context not recovered, iip 0x%lx\n",
			 pmsa->pmsa_iip);
}

/**
 * recover_from_platform_error - Recover from platform error.
 * @slidx:	pointer of index of SAL error record
 * @peidx:	pointer of index of processor error section
 * @pbci:	pointer of pal_bus_check_info
 * @sos:	pointer to hand off struct between SAL and OS
 *
 * Return value:
 *	1 on Success / 0 on Failure
 */

static int
recover_from_platform_error(slidx_table_t *slidx, peidx_table_t *peidx,
			    pal_bus_check_info_t *pbci,
			    struct ia64_sal_os_state *sos)
{
	int status = 0;
	pal_processor_state_info_t *psp =
		(pal_processor_state_info_t*)peidx_psp(peidx);

	if (psp->bc && pbci->eb && pbci->bsi == 0) {
		switch(pbci->type) {
		case 1: /* partial read */
		case 3: /* full line(cpu) read */
		case 9: /* I/O space read */
			status = recover_from_read_error(slidx, peidx, pbci,
							 sos);
			break;
		case 0: /* unknown */
		case 2: /* partial write */
		case 4: /* full line write */
		case 5: /* implicit or explicit write-back operation */
		case 6: /* snoop probe */
		case 7: /* incoming or outgoing ptc.g */
		case 8: /* write coalescing transactions */
		case 10: /* I/O space write */
		case 11: /* inter-processor interrupt message(IPI) */
		case 12: /* interrupt acknowledge or
				external task priority cycle */
		default:
			break;
		}
	} else if (psp->cc && !psp->bc) {	/* Cache error */
		status = recover_from_read_error(slidx, peidx, pbci, sos);
	}

	return status;
}

/*
 * recover_from_tlb_check
 * @peidx:	pointer of index of processor error section
 *
 * Return value:
 *	1 on Success / 0 on Failure
 */
static int
recover_from_tlb_check(peidx_table_t *peidx)
{
	sal_log_mod_error_info_t *smei;
	pal_tlb_check_info_t *ptci;

	smei = (sal_log_mod_error_info_t *)peidx_tlb_check(peidx, 0);
	ptci = (pal_tlb_check_info_t *)&(smei->check_info);

	/*
	 * Look for signature of a duplicate TLB DTC entry, which is
	 * a SW bug and always fatal.
	 */
	if (ptci->op == PAL_TLB_CHECK_OP_PURGE
	    && !(ptci->itr || ptci->dtc || ptci->itc))
		return fatal_mca("Duplicate TLB entry");

	return mca_recovered("TLB check recovered");
}

/**
 * recover_from_processor_error
 * @platform:	whether there are some platform error section or not
 * @slidx:	pointer of index of SAL error record
 * @peidx:	pointer of index of processor error section
 * @pbci:	pointer of pal_bus_check_info
 * @sos:	pointer to hand off struct between SAL and OS
 *
 * Return value:
 *	1 on Success / 0 on Failure
 */

static int
recover_from_processor_error(int platform, slidx_table_t *slidx,
			     peidx_table_t *peidx, pal_bus_check_info_t *pbci,
			     struct ia64_sal_os_state *sos)
{
	pal_processor_state_info_t *psp =
		(pal_processor_state_info_t*)peidx_psp(peidx);

	/*
	 * Processor recovery status must key off of the PAL recovery
	 * status in the Processor State Parameter.
	 */

	/*
	 * The machine check is corrected.
	 */
	if (psp->cm == 1)
		return mca_recovered("machine check is already corrected.");

	/*
	 * The error was not contained.  Software must be reset.
	 */
	if (psp->us || psp->ci == 0)
		return fatal_mca("error not contained");

	/*
	 * Look for recoverable TLB check
	 */
	if (psp->tc && !(psp->cc || psp->bc || psp->rc || psp->uc))
		return recover_from_tlb_check(peidx);

	/*
	 * The cache check and bus check bits have four possible states
	 *   cc bc
	 *    1  1	Memory error, attempt recovery
	 *    1  0	Cache error, attempt recovery
	 *    0  1	I/O error, attempt recovery
	 *    0  0	Other error type, not recovered
	 */
	if (psp->cc == 0 && (psp->bc == 0 || pbci == NULL))
		return fatal_mca("No cache or bus check");

	/*
	 * Cannot handle more than one bus check.
	 */
	if (peidx_bus_check_num(peidx) > 1)
		return fatal_mca("Too many bus checks");

	if (pbci->ib)
		return fatal_mca("Internal Bus error");
	if (pbci->eb && pbci->bsi > 0)
		return fatal_mca("External bus check fatal status");

	/*
	 * This is a local MCA and estimated as a recoverble error.
	 */
	if (platform)
		return recover_from_platform_error(slidx, peidx, pbci, sos);

	/*
	 * On account of strange SAL error record, we cannot recover.
	 */
	return fatal_mca("Strange SAL record");
}

/**
 * mca_try_to_recover - Try to recover from MCA
 * @rec:	pointer to a SAL error record
 * @sos:	pointer to hand off struct between SAL and OS
 *
 * Return value:
 *	1 on Success / 0 on Failure
 */

static int
mca_try_to_recover(void *rec, struct ia64_sal_os_state *sos)
{
	int platform_err;
	int n_proc_err;
	slidx_table_t slidx;
	peidx_table_t peidx;
	pal_bus_check_info_t pbci;

	/* Make index of SAL error record */
	platform_err = mca_make_slidx(rec, &slidx);

	/* Count processor error sections */
	n_proc_err = slidx_count(&slidx, proc_err);

	 /* Now, OS can recover when there is one processor error section */
	if (n_proc_err > 1)
		return fatal_mca("Too Many Errors");
	else if (n_proc_err == 0)
		/* Weird SAL record ... We can't do anything */
		return fatal_mca("Weird SAL record");

	/* Make index of processor error section */
	mca_make_peidx((sal_log_processor_info_t*)
		slidx_first_entry(&slidx.proc_err)->hdr, &peidx);

	/* Extract Processor BUS_CHECK[0] */
	*((u64*)&pbci) = peidx_check_info(&peidx, bus_check, 0);

	/* Check whether MCA is global or not */
	if (is_mca_global(&peidx, &pbci, sos))
		return fatal_mca("global MCA");
	
	/* Try to recover a processor error */
	return recover_from_processor_error(platform_err, &slidx, &peidx,
					    &pbci, sos);
}

/*
 * =============================================================================
 */

int __init mca_external_handler_init(void)
{
	if (init_record_index_pools())
		return -ENOMEM;

	/* register external mca handlers */
	if (ia64_reg_MCA_extension(mca_try_to_recover)) {	
		printk(KERN_ERR "ia64_reg_MCA_extension failed.\n");
		kfree(slidx_pool.buffer);
		return -EFAULT;
	}
	return 0;
}

void __exit mca_external_handler_exit(void)
{
	/* unregister external mca handlers */
	ia64_unreg_MCA_extension();
	kfree(slidx_pool.buffer);
}

module_init(mca_external_handler_init);
module_exit(mca_external_handler_exit);

module_param(sal_rec_max, int, 0644);
MODULE_PARM_DESC(sal_rec_max, "Max size of SAL error record");

MODULE_DESCRIPTION("ia64 platform dependent mca handler driver");
MODULE_LICENSE("GPL");