xref: /openbmc/linux/arch/ia64/kernel/mca_drv.c (revision b9b77222)
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_array(slidx_pool.max_idx, sizeof(slidx_list_t),
354 			      GFP_KERNEL);
355 
356 	return slidx_pool.buffer ? 0 : -ENOMEM;
357 }
358 
359 
360 /*****************************************************************************
361  * Recovery functions                                                        *
362  *****************************************************************************/
363 
364 /**
365  * is_mca_global - Check whether this MCA is global or not
366  * @peidx:	pointer of index of processor error section
367  * @pbci:	pointer to pal_bus_check_info_t
368  * @sos:	pointer to hand off struct between SAL and OS
369  *
370  * Return value:
371  *	MCA_IS_LOCAL / MCA_IS_GLOBAL
372  */
373 
374 static mca_type_t
375 is_mca_global(peidx_table_t *peidx, pal_bus_check_info_t *pbci,
376 	      struct ia64_sal_os_state *sos)
377 {
378 	pal_processor_state_info_t *psp =
379 		(pal_processor_state_info_t*)peidx_psp(peidx);
380 
381 	/*
382 	 * PAL can request a rendezvous, if the MCA has a global scope.
383 	 * If "rz_always" flag is set, SAL requests MCA rendezvous
384 	 * in spite of global MCA.
385 	 * Therefore it is local MCA when rendezvous has not been requested.
386 	 * Failed to rendezvous, the system must be down.
387 	 */
388 	switch (sos->rv_rc) {
389 		case -1: /* SAL rendezvous unsuccessful */
390 			return MCA_IS_GLOBAL;
391 		case  0: /* SAL rendezvous not required */
392 			return MCA_IS_LOCAL;
393 		case  1: /* SAL rendezvous successful int */
394 		case  2: /* SAL rendezvous successful int with init */
395 		default:
396 			break;
397 	}
398 
399 	/*
400 	 * If One or more Cache/TLB/Reg_File/Uarch_Check is here,
401 	 * it would be a local MCA. (i.e. processor internal error)
402 	 */
403 	if (psp->tc || psp->cc || psp->rc || psp->uc)
404 		return MCA_IS_LOCAL;
405 
406 	/*
407 	 * Bus_Check structure with Bus_Check.ib (internal bus error) flag set
408 	 * would be a global MCA. (e.g. a system bus address parity error)
409 	 */
410 	if (!pbci || pbci->ib)
411 		return MCA_IS_GLOBAL;
412 
413 	/*
414 	 * Bus_Check structure with Bus_Check.eb (external bus error) flag set
415 	 * could be either a local MCA or a global MCA.
416 	 *
417 	 * Referring Bus_Check.bsi:
418 	 *   0: Unknown/unclassified
419 	 *   1: BERR#
420 	 *   2: BINIT#
421 	 *   3: Hard Fail
422 	 * (FIXME: Are these SGI specific or generic bsi values?)
423 	 */
424 	if (pbci->eb)
425 		switch (pbci->bsi) {
426 			case 0:
427 				/* e.g. a load from poisoned memory */
428 				return MCA_IS_LOCAL;
429 			case 1:
430 			case 2:
431 			case 3:
432 				return MCA_IS_GLOBAL;
433 		}
434 
435 	return MCA_IS_GLOBAL;
436 }
437 
438 /**
439  * get_target_identifier - Get the valid Cache or Bus check target identifier.
440  * @peidx:	pointer of index of processor error section
441  *
442  * Return value:
443  *	target address on Success / 0 on Failure
444  */
445 static u64
446 get_target_identifier(peidx_table_t *peidx)
447 {
448 	u64 target_address = 0;
449 	sal_log_mod_error_info_t *smei;
450 	pal_cache_check_info_t *pcci;
451 	int i, level = 9;
452 
453 	/*
454 	 * Look through the cache checks for a valid target identifier
455 	 * If more than one valid target identifier, return the one
456 	 * with the lowest cache level.
457 	 */
458 	for (i = 0; i < peidx_cache_check_num(peidx); i++) {
459 		smei = (sal_log_mod_error_info_t *)peidx_cache_check(peidx, i);
460 		if (smei->valid.target_identifier && smei->target_identifier) {
461 			pcci = (pal_cache_check_info_t *)&(smei->check_info);
462 			if (!target_address || (pcci->level < level)) {
463 				target_address = smei->target_identifier;
464 				level = pcci->level;
465 				continue;
466 			}
467 		}
468 	}
469 	if (target_address)
470 		return target_address;
471 
472 	/*
473 	 * Look at the bus check for a valid target identifier
474 	 */
475 	smei = peidx_bus_check(peidx, 0);
476 	if (smei && smei->valid.target_identifier)
477 		return smei->target_identifier;
478 
479 	return 0;
480 }
481 
482 /**
483  * recover_from_read_error - Try to recover the errors which type are "read"s.
484  * @slidx:	pointer of index of SAL error record
485  * @peidx:	pointer of index of processor error section
486  * @pbci:	pointer of pal_bus_check_info
487  * @sos:	pointer to hand off struct between SAL and OS
488  *
489  * Return value:
490  *	1 on Success / 0 on Failure
491  */
492 
493 static int
494 recover_from_read_error(slidx_table_t *slidx,
495 			peidx_table_t *peidx, pal_bus_check_info_t *pbci,
496 			struct ia64_sal_os_state *sos)
497 {
498 	u64 target_identifier;
499 	pal_min_state_area_t *pmsa;
500 	struct ia64_psr *psr1, *psr2;
501 	ia64_fptr_t *mca_hdlr_bh = (ia64_fptr_t*)mca_handler_bhhook;
502 
503 	/* Is target address valid? */
504 	target_identifier = get_target_identifier(peidx);
505 	if (!target_identifier)
506 		return fatal_mca("target address not valid");
507 
508 	/*
509 	 * cpu read or memory-mapped io read
510 	 *
511 	 *    offending process  affected process  OS MCA do
512 	 *     kernel mode        kernel mode       down system
513 	 *     kernel mode        user   mode       kill the process
514 	 *     user   mode        kernel mode       down system (*)
515 	 *     user   mode        user   mode       kill the process
516 	 *
517 	 * (*) You could terminate offending user-mode process
518 	 *    if (pbci->pv && pbci->pl != 0) *and* if you sure
519 	 *    the process not have any locks of kernel.
520 	 */
521 
522 	/* Is minstate valid? */
523 	if (!peidx_bottom(peidx) || !(peidx_bottom(peidx)->valid.minstate))
524 		return fatal_mca("minstate not valid");
525 	psr1 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_ipsr);
526 	psr2 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_xpsr);
527 
528 	/*
529 	 *  Check the privilege level of interrupted context.
530 	 *   If it is user-mode, then terminate affected process.
531 	 */
532 
533 	pmsa = sos->pal_min_state;
534 	if (psr1->cpl != 0 ||
535 	   ((psr2->cpl != 0) && mca_recover_range(pmsa->pmsa_iip))) {
536 		/*
537 		 *  setup for resume to bottom half of MCA,
538 		 * "mca_handler_bhhook"
539 		 */
540 		/* pass to bhhook as argument (gr8, ...) */
541 		pmsa->pmsa_gr[8-1] = target_identifier;
542 		pmsa->pmsa_gr[9-1] = pmsa->pmsa_iip;
543 		pmsa->pmsa_gr[10-1] = pmsa->pmsa_ipsr;
544 		/* set interrupted return address (but no use) */
545 		pmsa->pmsa_br0 = pmsa->pmsa_iip;
546 		/* change resume address to bottom half */
547 		pmsa->pmsa_iip = mca_hdlr_bh->fp;
548 		pmsa->pmsa_gr[1-1] = mca_hdlr_bh->gp;
549 		/* set cpl with kernel mode */
550 		psr2 = (struct ia64_psr *)&pmsa->pmsa_ipsr;
551 		psr2->cpl = 0;
552 		psr2->ri  = 0;
553 		psr2->bn  = 1;
554 		psr2->i  = 0;
555 
556 		return mca_recovered("user memory corruption. "
557 				"kill affected process - recovered.");
558 	}
559 
560 	return fatal_mca("kernel context not recovered, iip 0x%lx\n",
561 			 pmsa->pmsa_iip);
562 }
563 
564 /**
565  * recover_from_platform_error - Recover from platform error.
566  * @slidx:	pointer of index of SAL error record
567  * @peidx:	pointer of index of processor error section
568  * @pbci:	pointer of pal_bus_check_info
569  * @sos:	pointer to hand off struct between SAL and OS
570  *
571  * Return value:
572  *	1 on Success / 0 on Failure
573  */
574 
575 static int
576 recover_from_platform_error(slidx_table_t *slidx, peidx_table_t *peidx,
577 			    pal_bus_check_info_t *pbci,
578 			    struct ia64_sal_os_state *sos)
579 {
580 	int status = 0;
581 	pal_processor_state_info_t *psp =
582 		(pal_processor_state_info_t*)peidx_psp(peidx);
583 
584 	if (psp->bc && pbci->eb && pbci->bsi == 0) {
585 		switch(pbci->type) {
586 		case 1: /* partial read */
587 		case 3: /* full line(cpu) read */
588 		case 9: /* I/O space read */
589 			status = recover_from_read_error(slidx, peidx, pbci,
590 							 sos);
591 			break;
592 		case 0: /* unknown */
593 		case 2: /* partial write */
594 		case 4: /* full line write */
595 		case 5: /* implicit or explicit write-back operation */
596 		case 6: /* snoop probe */
597 		case 7: /* incoming or outgoing ptc.g */
598 		case 8: /* write coalescing transactions */
599 		case 10: /* I/O space write */
600 		case 11: /* inter-processor interrupt message(IPI) */
601 		case 12: /* interrupt acknowledge or
602 				external task priority cycle */
603 		default:
604 			break;
605 		}
606 	} else if (psp->cc && !psp->bc) {	/* Cache error */
607 		status = recover_from_read_error(slidx, peidx, pbci, sos);
608 	}
609 
610 	return status;
611 }
612 
613 /*
614  * recover_from_tlb_check
615  * @peidx:	pointer of index of processor error section
616  *
617  * Return value:
618  *	1 on Success / 0 on Failure
619  */
620 static int
621 recover_from_tlb_check(peidx_table_t *peidx)
622 {
623 	sal_log_mod_error_info_t *smei;
624 	pal_tlb_check_info_t *ptci;
625 
626 	smei = (sal_log_mod_error_info_t *)peidx_tlb_check(peidx, 0);
627 	ptci = (pal_tlb_check_info_t *)&(smei->check_info);
628 
629 	/*
630 	 * Look for signature of a duplicate TLB DTC entry, which is
631 	 * a SW bug and always fatal.
632 	 */
633 	if (ptci->op == PAL_TLB_CHECK_OP_PURGE
634 	    && !(ptci->itr || ptci->dtc || ptci->itc))
635 		return fatal_mca("Duplicate TLB entry");
636 
637 	return mca_recovered("TLB check recovered");
638 }
639 
640 /**
641  * recover_from_processor_error
642  * @platform:	whether there are some platform error section or not
643  * @slidx:	pointer of index of SAL error record
644  * @peidx:	pointer of index of processor error section
645  * @pbci:	pointer of pal_bus_check_info
646  * @sos:	pointer to hand off struct between SAL and OS
647  *
648  * Return value:
649  *	1 on Success / 0 on Failure
650  */
651 
652 static int
653 recover_from_processor_error(int platform, slidx_table_t *slidx,
654 			     peidx_table_t *peidx, pal_bus_check_info_t *pbci,
655 			     struct ia64_sal_os_state *sos)
656 {
657 	pal_processor_state_info_t *psp =
658 		(pal_processor_state_info_t*)peidx_psp(peidx);
659 
660 	/*
661 	 * Processor recovery status must key off of the PAL recovery
662 	 * status in the Processor State Parameter.
663 	 */
664 
665 	/*
666 	 * The machine check is corrected.
667 	 */
668 	if (psp->cm == 1)
669 		return mca_recovered("machine check is already corrected.");
670 
671 	/*
672 	 * The error was not contained.  Software must be reset.
673 	 */
674 	if (psp->us || psp->ci == 0)
675 		return fatal_mca("error not contained");
676 
677 	/*
678 	 * Look for recoverable TLB check
679 	 */
680 	if (psp->tc && !(psp->cc || psp->bc || psp->rc || psp->uc))
681 		return recover_from_tlb_check(peidx);
682 
683 	/*
684 	 * The cache check and bus check bits have four possible states
685 	 *   cc bc
686 	 *    1  1	Memory error, attempt recovery
687 	 *    1  0	Cache error, attempt recovery
688 	 *    0  1	I/O error, attempt recovery
689 	 *    0  0	Other error type, not recovered
690 	 */
691 	if (psp->cc == 0 && (psp->bc == 0 || pbci == NULL))
692 		return fatal_mca("No cache or bus check");
693 
694 	/*
695 	 * Cannot handle more than one bus check.
696 	 */
697 	if (peidx_bus_check_num(peidx) > 1)
698 		return fatal_mca("Too many bus checks");
699 
700 	if (pbci->ib)
701 		return fatal_mca("Internal Bus error");
702 	if (pbci->eb && pbci->bsi > 0)
703 		return fatal_mca("External bus check fatal status");
704 
705 	/*
706 	 * This is a local MCA and estimated as a recoverable error.
707 	 */
708 	if (platform)
709 		return recover_from_platform_error(slidx, peidx, pbci, sos);
710 
711 	/*
712 	 * On account of strange SAL error record, we cannot recover.
713 	 */
714 	return fatal_mca("Strange SAL record");
715 }
716 
717 /**
718  * mca_try_to_recover - Try to recover from MCA
719  * @rec:	pointer to a SAL error record
720  * @sos:	pointer to hand off struct between SAL and OS
721  *
722  * Return value:
723  *	1 on Success / 0 on Failure
724  */
725 
726 static int
727 mca_try_to_recover(void *rec, struct ia64_sal_os_state *sos)
728 {
729 	int platform_err;
730 	int n_proc_err;
731 	slidx_table_t slidx;
732 	peidx_table_t peidx;
733 	pal_bus_check_info_t pbci;
734 
735 	/* Make index of SAL error record */
736 	platform_err = mca_make_slidx(rec, &slidx);
737 
738 	/* Count processor error sections */
739 	n_proc_err = slidx_count(&slidx, proc_err);
740 
741 	 /* Now, OS can recover when there is one processor error section */
742 	if (n_proc_err > 1)
743 		return fatal_mca("Too Many Errors");
744 	else if (n_proc_err == 0)
745 		/* Weird SAL record ... We can't do anything */
746 		return fatal_mca("Weird SAL record");
747 
748 	/* Make index of processor error section */
749 	mca_make_peidx((sal_log_processor_info_t*)
750 		slidx_first_entry(&slidx.proc_err)->hdr, &peidx);
751 
752 	/* Extract Processor BUS_CHECK[0] */
753 	*((u64*)&pbci) = peidx_check_info(&peidx, bus_check, 0);
754 
755 	/* Check whether MCA is global or not */
756 	if (is_mca_global(&peidx, &pbci, sos))
757 		return fatal_mca("global MCA");
758 
759 	/* Try to recover a processor error */
760 	return recover_from_processor_error(platform_err, &slidx, &peidx,
761 					    &pbci, sos);
762 }
763 
764 /*
765  * =============================================================================
766  */
767 
768 int __init mca_external_handler_init(void)
769 {
770 	if (init_record_index_pools())
771 		return -ENOMEM;
772 
773 	/* register external mca handlers */
774 	if (ia64_reg_MCA_extension(mca_try_to_recover)) {
775 		printk(KERN_ERR "ia64_reg_MCA_extension failed.\n");
776 		kfree(slidx_pool.buffer);
777 		return -EFAULT;
778 	}
779 	return 0;
780 }
781 
782 void __exit mca_external_handler_exit(void)
783 {
784 	/* unregister external mca handlers */
785 	ia64_unreg_MCA_extension();
786 	kfree(slidx_pool.buffer);
787 }
788 
789 module_init(mca_external_handler_init);
790 module_exit(mca_external_handler_exit);
791 
792 module_param(sal_rec_max, int, 0644);
793 MODULE_PARM_DESC(sal_rec_max, "Max size of SAL error record");
794 
795 MODULE_DESCRIPTION("ia64 platform dependent mca handler driver");
796 MODULE_LICENSE("GPL");
797