xref: /openbmc/linux/arch/ia64/kernel/mca_drv.c (revision 293d5b43)
1 /*
2  * File:	mca_drv.c
3  * Purpose:	Generic MCA handling layer
4  *
5  * Copyright (C) 2004 FUJITSU LIMITED
6  * Copyright (C) 2004 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
7  * Copyright (C) 2005 Silicon Graphics, Inc
8  * Copyright (C) 2005 Keith Owens <kaos@sgi.com>
9  * Copyright (C) 2006 Russ Anderson <rja@sgi.com>
10  */
11 #include <linux/types.h>
12 #include <linux/init.h>
13 #include <linux/sched.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/kallsyms.h>
17 #include <linux/bootmem.h>
18 #include <linux/acpi.h>
19 #include <linux/timer.h>
20 #include <linux/module.h>
21 #include <linux/kernel.h>
22 #include <linux/smp.h>
23 #include <linux/workqueue.h>
24 #include <linux/mm.h>
25 #include <linux/slab.h>
26 
27 #include <asm/delay.h>
28 #include <asm/machvec.h>
29 #include <asm/page.h>
30 #include <asm/ptrace.h>
31 #include <asm/sal.h>
32 #include <asm/mca.h>
33 
34 #include <asm/irq.h>
35 #include <asm/hw_irq.h>
36 
37 #include "mca_drv.h"
38 
39 /* max size of SAL error record (default) */
40 static int sal_rec_max = 10000;
41 
42 /* from mca_drv_asm.S */
43 extern void *mca_handler_bhhook(void);
44 
45 static DEFINE_SPINLOCK(mca_bh_lock);
46 
47 typedef enum {
48 	MCA_IS_LOCAL  = 0,
49 	MCA_IS_GLOBAL = 1
50 } mca_type_t;
51 
52 #define MAX_PAGE_ISOLATE 1024
53 
54 static struct page *page_isolate[MAX_PAGE_ISOLATE];
55 static int num_page_isolate = 0;
56 
57 typedef enum {
58 	ISOLATE_NG,
59 	ISOLATE_OK,
60 	ISOLATE_NONE
61 } isolate_status_t;
62 
63 typedef enum {
64 	MCA_NOT_RECOVERED = 0,
65 	MCA_RECOVERED	  = 1
66 } recovery_status_t;
67 
68 /*
69  *  This pool keeps pointers to the section part of SAL error record
70  */
71 static struct {
72 	slidx_list_t *buffer; /* section pointer list pool */
73 	int	     cur_idx; /* Current index of section pointer list pool */
74 	int	     max_idx; /* Maximum index of section pointer list pool */
75 } slidx_pool;
76 
77 static int
78 fatal_mca(const char *fmt, ...)
79 {
80 	va_list args;
81 	char buf[256];
82 
83 	va_start(args, fmt);
84 	vsnprintf(buf, sizeof(buf), fmt, args);
85 	va_end(args);
86 	ia64_mca_printk(KERN_ALERT "MCA: %s\n", buf);
87 
88 	return MCA_NOT_RECOVERED;
89 }
90 
91 static int
92 mca_recovered(const char *fmt, ...)
93 {
94 	va_list args;
95 	char buf[256];
96 
97 	va_start(args, fmt);
98 	vsnprintf(buf, sizeof(buf), fmt, args);
99 	va_end(args);
100 	ia64_mca_printk(KERN_INFO "MCA: %s\n", buf);
101 
102 	return MCA_RECOVERED;
103 }
104 
105 /**
106  * mca_page_isolate - isolate a poisoned page in order not to use it later
107  * @paddr:	poisoned memory location
108  *
109  * Return value:
110  *	one of isolate_status_t, ISOLATE_OK/NG/NONE.
111  */
112 
113 static isolate_status_t
114 mca_page_isolate(unsigned long paddr)
115 {
116 	int i;
117 	struct page *p;
118 
119 	/* whether physical address is valid or not */
120 	if (!ia64_phys_addr_valid(paddr))
121 		return ISOLATE_NONE;
122 
123 	if (!pfn_valid(paddr >> PAGE_SHIFT))
124 		return ISOLATE_NONE;
125 
126 	/* convert physical address to physical page number */
127 	p = pfn_to_page(paddr>>PAGE_SHIFT);
128 
129 	/* check whether a page number have been already registered or not */
130 	for (i = 0; i < num_page_isolate; i++)
131 		if (page_isolate[i] == p)
132 			return ISOLATE_OK; /* already listed */
133 
134 	/* limitation check */
135 	if (num_page_isolate == MAX_PAGE_ISOLATE)
136 		return ISOLATE_NG;
137 
138 	/* kick pages having attribute 'SLAB' or 'Reserved' */
139 	if (PageSlab(p) || PageReserved(p))
140 		return ISOLATE_NG;
141 
142 	/* add attribute 'Reserved' and register the page */
143 	get_page(p);
144 	SetPageReserved(p);
145 	page_isolate[num_page_isolate++] = p;
146 
147 	return ISOLATE_OK;
148 }
149 
150 /**
151  * mca_hanlder_bh - Kill the process which occurred memory read error
152  * @paddr:	poisoned address received from MCA Handler
153  */
154 
155 void
156 mca_handler_bh(unsigned long paddr, void *iip, unsigned long ipsr)
157 {
158 	ia64_mlogbuf_dump();
159 	printk(KERN_ERR "OS_MCA: process [cpu %d, pid: %d, uid: %d, "
160 		"iip: %p, psr: 0x%lx,paddr: 0x%lx](%s) encounters MCA.\n",
161 	       raw_smp_processor_id(), current->pid,
162 		from_kuid(&init_user_ns, current_uid()),
163 		iip, ipsr, paddr, current->comm);
164 
165 	spin_lock(&mca_bh_lock);
166 	switch (mca_page_isolate(paddr)) {
167 	case ISOLATE_OK:
168 		printk(KERN_DEBUG "Page isolation: ( %lx ) success.\n", paddr);
169 		break;
170 	case ISOLATE_NG:
171 		printk(KERN_CRIT "Page isolation: ( %lx ) failure.\n", paddr);
172 		break;
173 	default:
174 		break;
175 	}
176 	spin_unlock(&mca_bh_lock);
177 
178 	/* This process is about to be killed itself */
179 	do_exit(SIGKILL);
180 }
181 
182 /**
183  * mca_make_peidx - Make index of processor error section
184  * @slpi:	pointer to record of processor error section
185  * @peidx:	pointer to index of processor error section
186  */
187 
188 static void
189 mca_make_peidx(sal_log_processor_info_t *slpi, peidx_table_t *peidx)
190 {
191 	/*
192 	 * calculate the start address of
193 	 *   "struct cpuid_info" and "sal_processor_static_info_t".
194 	 */
195 	u64 total_check_num = slpi->valid.num_cache_check
196 				+ slpi->valid.num_tlb_check
197 				+ slpi->valid.num_bus_check
198 				+ slpi->valid.num_reg_file_check
199 				+ slpi->valid.num_ms_check;
200 	u64 head_size =	sizeof(sal_log_mod_error_info_t) * total_check_num
201 			+ sizeof(sal_log_processor_info_t);
202 	u64 mid_size  = slpi->valid.cpuid_info * sizeof(struct sal_cpuid_info);
203 
204 	peidx_head(peidx)   = slpi;
205 	peidx_mid(peidx)    = (struct sal_cpuid_info *)
206 		(slpi->valid.cpuid_info ? ((char*)slpi + head_size) : NULL);
207 	peidx_bottom(peidx) = (sal_processor_static_info_t *)
208 		(slpi->valid.psi_static_struct ?
209 			((char*)slpi + head_size + mid_size) : NULL);
210 }
211 
212 /**
213  * mca_make_slidx -  Make index of SAL error record
214  * @buffer:	pointer to SAL error record
215  * @slidx:	pointer to index of SAL error record
216  *
217  * Return value:
218  *	1 if record has platform error / 0 if not
219  */
220 #define LOG_INDEX_ADD_SECT_PTR(sect, ptr) \
221 	{slidx_list_t *hl = &slidx_pool.buffer[slidx_pool.cur_idx]; \
222 	hl->hdr = ptr; \
223 	list_add(&hl->list, &(sect)); \
224 	slidx_pool.cur_idx = (slidx_pool.cur_idx + 1)%slidx_pool.max_idx; }
225 
226 static int
227 mca_make_slidx(void *buffer, slidx_table_t *slidx)
228 {
229 	int platform_err = 0;
230 	int record_len = ((sal_log_record_header_t*)buffer)->len;
231 	u32 ercd_pos;
232 	int sects;
233 	sal_log_section_hdr_t *sp;
234 
235 	/*
236 	 * Initialize index referring current record
237 	 */
238 	INIT_LIST_HEAD(&(slidx->proc_err));
239 	INIT_LIST_HEAD(&(slidx->mem_dev_err));
240 	INIT_LIST_HEAD(&(slidx->sel_dev_err));
241 	INIT_LIST_HEAD(&(slidx->pci_bus_err));
242 	INIT_LIST_HEAD(&(slidx->smbios_dev_err));
243 	INIT_LIST_HEAD(&(slidx->pci_comp_err));
244 	INIT_LIST_HEAD(&(slidx->plat_specific_err));
245 	INIT_LIST_HEAD(&(slidx->host_ctlr_err));
246 	INIT_LIST_HEAD(&(slidx->plat_bus_err));
247 	INIT_LIST_HEAD(&(slidx->unsupported));
248 
249 	/*
250 	 * Extract a Record Header
251 	 */
252 	slidx->header = buffer;
253 
254 	/*
255 	 * Extract each section records
256 	 * (arranged from "int ia64_log_platform_info_print()")
257 	 */
258 	for (ercd_pos = sizeof(sal_log_record_header_t), sects = 0;
259 		ercd_pos < record_len; ercd_pos += sp->len, sects++) {
260 		sp = (sal_log_section_hdr_t *)((char*)buffer + ercd_pos);
261 		if (!efi_guidcmp(sp->guid, SAL_PROC_DEV_ERR_SECT_GUID)) {
262 			LOG_INDEX_ADD_SECT_PTR(slidx->proc_err, sp);
263 		} else if (!efi_guidcmp(sp->guid,
264 				SAL_PLAT_MEM_DEV_ERR_SECT_GUID)) {
265 			platform_err = 1;
266 			LOG_INDEX_ADD_SECT_PTR(slidx->mem_dev_err, sp);
267 		} else if (!efi_guidcmp(sp->guid,
268 				SAL_PLAT_SEL_DEV_ERR_SECT_GUID)) {
269 			platform_err = 1;
270 			LOG_INDEX_ADD_SECT_PTR(slidx->sel_dev_err, sp);
271 		} else if (!efi_guidcmp(sp->guid,
272 				SAL_PLAT_PCI_BUS_ERR_SECT_GUID)) {
273 			platform_err = 1;
274 			LOG_INDEX_ADD_SECT_PTR(slidx->pci_bus_err, sp);
275 		} else if (!efi_guidcmp(sp->guid,
276 				SAL_PLAT_SMBIOS_DEV_ERR_SECT_GUID)) {
277 			platform_err = 1;
278 			LOG_INDEX_ADD_SECT_PTR(slidx->smbios_dev_err, sp);
279 		} else if (!efi_guidcmp(sp->guid,
280 				SAL_PLAT_PCI_COMP_ERR_SECT_GUID)) {
281 			platform_err = 1;
282 			LOG_INDEX_ADD_SECT_PTR(slidx->pci_comp_err, sp);
283 		} else if (!efi_guidcmp(sp->guid,
284 				SAL_PLAT_SPECIFIC_ERR_SECT_GUID)) {
285 			platform_err = 1;
286 			LOG_INDEX_ADD_SECT_PTR(slidx->plat_specific_err, sp);
287 		} else if (!efi_guidcmp(sp->guid,
288 				SAL_PLAT_HOST_CTLR_ERR_SECT_GUID)) {
289 			platform_err = 1;
290 			LOG_INDEX_ADD_SECT_PTR(slidx->host_ctlr_err, sp);
291 		} else if (!efi_guidcmp(sp->guid,
292 				SAL_PLAT_BUS_ERR_SECT_GUID)) {
293 			platform_err = 1;
294 			LOG_INDEX_ADD_SECT_PTR(slidx->plat_bus_err, sp);
295 		} else {
296 			LOG_INDEX_ADD_SECT_PTR(slidx->unsupported, sp);
297 		}
298 	}
299 	slidx->n_sections = sects;
300 
301 	return platform_err;
302 }
303 
304 /**
305  * init_record_index_pools - Initialize pool of lists for SAL record index
306  *
307  * Return value:
308  *	0 on Success / -ENOMEM on Failure
309  */
310 static int
311 init_record_index_pools(void)
312 {
313 	int i;
314 	int rec_max_size;  /* Maximum size of SAL error records */
315 	int sect_min_size; /* Minimum size of SAL error sections */
316 	/* minimum size table of each section */
317 	static int sal_log_sect_min_sizes[] = {
318 		sizeof(sal_log_processor_info_t)
319 		+ sizeof(sal_processor_static_info_t),
320 		sizeof(sal_log_mem_dev_err_info_t),
321 		sizeof(sal_log_sel_dev_err_info_t),
322 		sizeof(sal_log_pci_bus_err_info_t),
323 		sizeof(sal_log_smbios_dev_err_info_t),
324 		sizeof(sal_log_pci_comp_err_info_t),
325 		sizeof(sal_log_plat_specific_err_info_t),
326 		sizeof(sal_log_host_ctlr_err_info_t),
327 		sizeof(sal_log_plat_bus_err_info_t),
328 	};
329 
330 	/*
331 	 * MCA handler cannot allocate new memory on flight,
332 	 * so we preallocate enough memory to handle a SAL record.
333 	 *
334 	 * Initialize a handling set of slidx_pool:
335 	 *   1. Pick up the max size of SAL error records
336 	 *   2. Pick up the min size of SAL error sections
337 	 *   3. Allocate the pool as enough to 2 SAL records
338 	 *     (now we can estimate the maxinum of section in a record.)
339 	 */
340 
341 	/* - 1 - */
342 	rec_max_size = sal_rec_max;
343 
344 	/* - 2 - */
345 	sect_min_size = sal_log_sect_min_sizes[0];
346 	for (i = 1; i < sizeof sal_log_sect_min_sizes/sizeof(size_t); i++)
347 		if (sect_min_size > sal_log_sect_min_sizes[i])
348 			sect_min_size = sal_log_sect_min_sizes[i];
349 
350 	/* - 3 - */
351 	slidx_pool.max_idx = (rec_max_size/sect_min_size) * 2 + 1;
352 	slidx_pool.buffer =
353 		kmalloc(slidx_pool.max_idx * sizeof(slidx_list_t), GFP_KERNEL);
354 
355 	return slidx_pool.buffer ? 0 : -ENOMEM;
356 }
357 
358 
359 /*****************************************************************************
360  * Recovery functions                                                        *
361  *****************************************************************************/
362 
363 /**
364  * is_mca_global - Check whether this MCA is global or not
365  * @peidx:	pointer of index of processor error section
366  * @pbci:	pointer to pal_bus_check_info_t
367  * @sos:	pointer to hand off struct between SAL and OS
368  *
369  * Return value:
370  *	MCA_IS_LOCAL / MCA_IS_GLOBAL
371  */
372 
373 static mca_type_t
374 is_mca_global(peidx_table_t *peidx, pal_bus_check_info_t *pbci,
375 	      struct ia64_sal_os_state *sos)
376 {
377 	pal_processor_state_info_t *psp =
378 		(pal_processor_state_info_t*)peidx_psp(peidx);
379 
380 	/*
381 	 * PAL can request a rendezvous, if the MCA has a global scope.
382 	 * If "rz_always" flag is set, SAL requests MCA rendezvous
383 	 * in spite of global MCA.
384 	 * Therefore it is local MCA when rendezvous has not been requested.
385 	 * Failed to rendezvous, the system must be down.
386 	 */
387 	switch (sos->rv_rc) {
388 		case -1: /* SAL rendezvous unsuccessful */
389 			return MCA_IS_GLOBAL;
390 		case  0: /* SAL rendezvous not required */
391 			return MCA_IS_LOCAL;
392 		case  1: /* SAL rendezvous successful int */
393 		case  2: /* SAL rendezvous successful int with init */
394 		default:
395 			break;
396 	}
397 
398 	/*
399 	 * If One or more Cache/TLB/Reg_File/Uarch_Check is here,
400 	 * it would be a local MCA. (i.e. processor internal error)
401 	 */
402 	if (psp->tc || psp->cc || psp->rc || psp->uc)
403 		return MCA_IS_LOCAL;
404 
405 	/*
406 	 * Bus_Check structure with Bus_Check.ib (internal bus error) flag set
407 	 * would be a global MCA. (e.g. a system bus address parity error)
408 	 */
409 	if (!pbci || pbci->ib)
410 		return MCA_IS_GLOBAL;
411 
412 	/*
413 	 * Bus_Check structure with Bus_Check.eb (external bus error) flag set
414 	 * could be either a local MCA or a global MCA.
415 	 *
416 	 * Referring Bus_Check.bsi:
417 	 *   0: Unknown/unclassified
418 	 *   1: BERR#
419 	 *   2: BINIT#
420 	 *   3: Hard Fail
421 	 * (FIXME: Are these SGI specific or generic bsi values?)
422 	 */
423 	if (pbci->eb)
424 		switch (pbci->bsi) {
425 			case 0:
426 				/* e.g. a load from poisoned memory */
427 				return MCA_IS_LOCAL;
428 			case 1:
429 			case 2:
430 			case 3:
431 				return MCA_IS_GLOBAL;
432 		}
433 
434 	return MCA_IS_GLOBAL;
435 }
436 
437 /**
438  * get_target_identifier - Get the valid Cache or Bus check target identifier.
439  * @peidx:	pointer of index of processor error section
440  *
441  * Return value:
442  *	target address on Success / 0 on Failure
443  */
444 static u64
445 get_target_identifier(peidx_table_t *peidx)
446 {
447 	u64 target_address = 0;
448 	sal_log_mod_error_info_t *smei;
449 	pal_cache_check_info_t *pcci;
450 	int i, level = 9;
451 
452 	/*
453 	 * Look through the cache checks for a valid target identifier
454 	 * If more than one valid target identifier, return the one
455 	 * with the lowest cache level.
456 	 */
457 	for (i = 0; i < peidx_cache_check_num(peidx); i++) {
458 		smei = (sal_log_mod_error_info_t *)peidx_cache_check(peidx, i);
459 		if (smei->valid.target_identifier && smei->target_identifier) {
460 			pcci = (pal_cache_check_info_t *)&(smei->check_info);
461 			if (!target_address || (pcci->level < level)) {
462 				target_address = smei->target_identifier;
463 				level = pcci->level;
464 				continue;
465 			}
466 		}
467 	}
468 	if (target_address)
469 		return target_address;
470 
471 	/*
472 	 * Look at the bus check for a valid target identifier
473 	 */
474 	smei = peidx_bus_check(peidx, 0);
475 	if (smei && smei->valid.target_identifier)
476 		return smei->target_identifier;
477 
478 	return 0;
479 }
480 
481 /**
482  * recover_from_read_error - Try to recover the errors which type are "read"s.
483  * @slidx:	pointer of index of SAL error record
484  * @peidx:	pointer of index of processor error section
485  * @pbci:	pointer of pal_bus_check_info
486  * @sos:	pointer to hand off struct between SAL and OS
487  *
488  * Return value:
489  *	1 on Success / 0 on Failure
490  */
491 
492 static int
493 recover_from_read_error(slidx_table_t *slidx,
494 			peidx_table_t *peidx, pal_bus_check_info_t *pbci,
495 			struct ia64_sal_os_state *sos)
496 {
497 	u64 target_identifier;
498 	pal_min_state_area_t *pmsa;
499 	struct ia64_psr *psr1, *psr2;
500 	ia64_fptr_t *mca_hdlr_bh = (ia64_fptr_t*)mca_handler_bhhook;
501 
502 	/* Is target address valid? */
503 	target_identifier = get_target_identifier(peidx);
504 	if (!target_identifier)
505 		return fatal_mca("target address not valid");
506 
507 	/*
508 	 * cpu read or memory-mapped io read
509 	 *
510 	 *    offending process  affected process  OS MCA do
511 	 *     kernel mode        kernel mode       down system
512 	 *     kernel mode        user   mode       kill the process
513 	 *     user   mode        kernel mode       down system (*)
514 	 *     user   mode        user   mode       kill the process
515 	 *
516 	 * (*) You could terminate offending user-mode process
517 	 *    if (pbci->pv && pbci->pl != 0) *and* if you sure
518 	 *    the process not have any locks of kernel.
519 	 */
520 
521 	/* Is minstate valid? */
522 	if (!peidx_bottom(peidx) || !(peidx_bottom(peidx)->valid.minstate))
523 		return fatal_mca("minstate not valid");
524 	psr1 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_ipsr);
525 	psr2 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_xpsr);
526 
527 	/*
528 	 *  Check the privilege level of interrupted context.
529 	 *   If it is user-mode, then terminate affected process.
530 	 */
531 
532 	pmsa = sos->pal_min_state;
533 	if (psr1->cpl != 0 ||
534 	   ((psr2->cpl != 0) && mca_recover_range(pmsa->pmsa_iip))) {
535 		/*
536 		 *  setup for resume to bottom half of MCA,
537 		 * "mca_handler_bhhook"
538 		 */
539 		/* pass to bhhook as argument (gr8, ...) */
540 		pmsa->pmsa_gr[8-1] = target_identifier;
541 		pmsa->pmsa_gr[9-1] = pmsa->pmsa_iip;
542 		pmsa->pmsa_gr[10-1] = pmsa->pmsa_ipsr;
543 		/* set interrupted return address (but no use) */
544 		pmsa->pmsa_br0 = pmsa->pmsa_iip;
545 		/* change resume address to bottom half */
546 		pmsa->pmsa_iip = mca_hdlr_bh->fp;
547 		pmsa->pmsa_gr[1-1] = mca_hdlr_bh->gp;
548 		/* set cpl with kernel mode */
549 		psr2 = (struct ia64_psr *)&pmsa->pmsa_ipsr;
550 		psr2->cpl = 0;
551 		psr2->ri  = 0;
552 		psr2->bn  = 1;
553 		psr2->i  = 0;
554 
555 		return mca_recovered("user memory corruption. "
556 				"kill affected process - recovered.");
557 	}
558 
559 	return fatal_mca("kernel context not recovered, iip 0x%lx\n",
560 			 pmsa->pmsa_iip);
561 }
562 
563 /**
564  * recover_from_platform_error - Recover from platform error.
565  * @slidx:	pointer of index of SAL error record
566  * @peidx:	pointer of index of processor error section
567  * @pbci:	pointer of pal_bus_check_info
568  * @sos:	pointer to hand off struct between SAL and OS
569  *
570  * Return value:
571  *	1 on Success / 0 on Failure
572  */
573 
574 static int
575 recover_from_platform_error(slidx_table_t *slidx, peidx_table_t *peidx,
576 			    pal_bus_check_info_t *pbci,
577 			    struct ia64_sal_os_state *sos)
578 {
579 	int status = 0;
580 	pal_processor_state_info_t *psp =
581 		(pal_processor_state_info_t*)peidx_psp(peidx);
582 
583 	if (psp->bc && pbci->eb && pbci->bsi == 0) {
584 		switch(pbci->type) {
585 		case 1: /* partial read */
586 		case 3: /* full line(cpu) read */
587 		case 9: /* I/O space read */
588 			status = recover_from_read_error(slidx, peidx, pbci,
589 							 sos);
590 			break;
591 		case 0: /* unknown */
592 		case 2: /* partial write */
593 		case 4: /* full line write */
594 		case 5: /* implicit or explicit write-back operation */
595 		case 6: /* snoop probe */
596 		case 7: /* incoming or outgoing ptc.g */
597 		case 8: /* write coalescing transactions */
598 		case 10: /* I/O space write */
599 		case 11: /* inter-processor interrupt message(IPI) */
600 		case 12: /* interrupt acknowledge or
601 				external task priority cycle */
602 		default:
603 			break;
604 		}
605 	} else if (psp->cc && !psp->bc) {	/* Cache error */
606 		status = recover_from_read_error(slidx, peidx, pbci, sos);
607 	}
608 
609 	return status;
610 }
611 
612 /*
613  * recover_from_tlb_check
614  * @peidx:	pointer of index of processor error section
615  *
616  * Return value:
617  *	1 on Success / 0 on Failure
618  */
619 static int
620 recover_from_tlb_check(peidx_table_t *peidx)
621 {
622 	sal_log_mod_error_info_t *smei;
623 	pal_tlb_check_info_t *ptci;
624 
625 	smei = (sal_log_mod_error_info_t *)peidx_tlb_check(peidx, 0);
626 	ptci = (pal_tlb_check_info_t *)&(smei->check_info);
627 
628 	/*
629 	 * Look for signature of a duplicate TLB DTC entry, which is
630 	 * a SW bug and always fatal.
631 	 */
632 	if (ptci->op == PAL_TLB_CHECK_OP_PURGE
633 	    && !(ptci->itr || ptci->dtc || ptci->itc))
634 		return fatal_mca("Duplicate TLB entry");
635 
636 	return mca_recovered("TLB check recovered");
637 }
638 
639 /**
640  * recover_from_processor_error
641  * @platform:	whether there are some platform error section or not
642  * @slidx:	pointer of index of SAL error record
643  * @peidx:	pointer of index of processor error section
644  * @pbci:	pointer of pal_bus_check_info
645  * @sos:	pointer to hand off struct between SAL and OS
646  *
647  * Return value:
648  *	1 on Success / 0 on Failure
649  */
650 
651 static int
652 recover_from_processor_error(int platform, slidx_table_t *slidx,
653 			     peidx_table_t *peidx, pal_bus_check_info_t *pbci,
654 			     struct ia64_sal_os_state *sos)
655 {
656 	pal_processor_state_info_t *psp =
657 		(pal_processor_state_info_t*)peidx_psp(peidx);
658 
659 	/*
660 	 * Processor recovery status must key off of the PAL recovery
661 	 * status in the Processor State Parameter.
662 	 */
663 
664 	/*
665 	 * The machine check is corrected.
666 	 */
667 	if (psp->cm == 1)
668 		return mca_recovered("machine check is already corrected.");
669 
670 	/*
671 	 * The error was not contained.  Software must be reset.
672 	 */
673 	if (psp->us || psp->ci == 0)
674 		return fatal_mca("error not contained");
675 
676 	/*
677 	 * Look for recoverable TLB check
678 	 */
679 	if (psp->tc && !(psp->cc || psp->bc || psp->rc || psp->uc))
680 		return recover_from_tlb_check(peidx);
681 
682 	/*
683 	 * The cache check and bus check bits have four possible states
684 	 *   cc bc
685 	 *    1  1	Memory error, attempt recovery
686 	 *    1  0	Cache error, attempt recovery
687 	 *    0  1	I/O error, attempt recovery
688 	 *    0  0	Other error type, not recovered
689 	 */
690 	if (psp->cc == 0 && (psp->bc == 0 || pbci == NULL))
691 		return fatal_mca("No cache or bus check");
692 
693 	/*
694 	 * Cannot handle more than one bus check.
695 	 */
696 	if (peidx_bus_check_num(peidx) > 1)
697 		return fatal_mca("Too many bus checks");
698 
699 	if (pbci->ib)
700 		return fatal_mca("Internal Bus error");
701 	if (pbci->eb && pbci->bsi > 0)
702 		return fatal_mca("External bus check fatal status");
703 
704 	/*
705 	 * This is a local MCA and estimated as a recoverable error.
706 	 */
707 	if (platform)
708 		return recover_from_platform_error(slidx, peidx, pbci, sos);
709 
710 	/*
711 	 * On account of strange SAL error record, we cannot recover.
712 	 */
713 	return fatal_mca("Strange SAL record");
714 }
715 
716 /**
717  * mca_try_to_recover - Try to recover from MCA
718  * @rec:	pointer to a SAL error record
719  * @sos:	pointer to hand off struct between SAL and OS
720  *
721  * Return value:
722  *	1 on Success / 0 on Failure
723  */
724 
725 static int
726 mca_try_to_recover(void *rec, struct ia64_sal_os_state *sos)
727 {
728 	int platform_err;
729 	int n_proc_err;
730 	slidx_table_t slidx;
731 	peidx_table_t peidx;
732 	pal_bus_check_info_t pbci;
733 
734 	/* Make index of SAL error record */
735 	platform_err = mca_make_slidx(rec, &slidx);
736 
737 	/* Count processor error sections */
738 	n_proc_err = slidx_count(&slidx, proc_err);
739 
740 	 /* Now, OS can recover when there is one processor error section */
741 	if (n_proc_err > 1)
742 		return fatal_mca("Too Many Errors");
743 	else if (n_proc_err == 0)
744 		/* Weird SAL record ... We can't do anything */
745 		return fatal_mca("Weird SAL record");
746 
747 	/* Make index of processor error section */
748 	mca_make_peidx((sal_log_processor_info_t*)
749 		slidx_first_entry(&slidx.proc_err)->hdr, &peidx);
750 
751 	/* Extract Processor BUS_CHECK[0] */
752 	*((u64*)&pbci) = peidx_check_info(&peidx, bus_check, 0);
753 
754 	/* Check whether MCA is global or not */
755 	if (is_mca_global(&peidx, &pbci, sos))
756 		return fatal_mca("global MCA");
757 
758 	/* Try to recover a processor error */
759 	return recover_from_processor_error(platform_err, &slidx, &peidx,
760 					    &pbci, sos);
761 }
762 
763 /*
764  * =============================================================================
765  */
766 
767 int __init mca_external_handler_init(void)
768 {
769 	if (init_record_index_pools())
770 		return -ENOMEM;
771 
772 	/* register external mca handlers */
773 	if (ia64_reg_MCA_extension(mca_try_to_recover)) {
774 		printk(KERN_ERR "ia64_reg_MCA_extension failed.\n");
775 		kfree(slidx_pool.buffer);
776 		return -EFAULT;
777 	}
778 	return 0;
779 }
780 
781 void __exit mca_external_handler_exit(void)
782 {
783 	/* unregister external mca handlers */
784 	ia64_unreg_MCA_extension();
785 	kfree(slidx_pool.buffer);
786 }
787 
788 module_init(mca_external_handler_init);
789 module_exit(mca_external_handler_exit);
790 
791 module_param(sal_rec_max, int, 0644);
792 MODULE_PARM_DESC(sal_rec_max, "Max size of SAL error record");
793 
794 MODULE_DESCRIPTION("ia64 platform dependent mca handler driver");
795 MODULE_LICENSE("GPL");
796