xref: /openbmc/linux/arch/ia64/kernel/mca_drv.c (revision 113094f7)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * File:	mca_drv.c
4  * Purpose:	Generic MCA handling layer
5  *
6  * Copyright (C) 2004 FUJITSU LIMITED
7  * Copyright (C) 2004 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
8  * Copyright (C) 2005 Silicon Graphics, Inc
9  * Copyright (C) 2005 Keith Owens <kaos@sgi.com>
10  * Copyright (C) 2006 Russ Anderson <rja@sgi.com>
11  */
12 #include <linux/types.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/interrupt.h>
16 #include <linux/irq.h>
17 #include <linux/kallsyms.h>
18 #include <linux/memblock.h>
19 #include <linux/acpi.h>
20 #include <linux/timer.h>
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/smp.h>
24 #include <linux/workqueue.h>
25 #include <linux/mm.h>
26 #include <linux/slab.h>
27 
28 #include <asm/delay.h>
29 #include <asm/machvec.h>
30 #include <asm/page.h>
31 #include <asm/ptrace.h>
32 #include <asm/sal.h>
33 #include <asm/mca.h>
34 
35 #include <asm/irq.h>
36 #include <asm/hw_irq.h>
37 
38 #include "mca_drv.h"
39 
40 /* max size of SAL error record (default) */
41 static int sal_rec_max = 10000;
42 
43 /* from mca_drv_asm.S */
44 extern void *mca_handler_bhhook(void);
45 
46 static DEFINE_SPINLOCK(mca_bh_lock);
47 
48 typedef enum {
49 	MCA_IS_LOCAL  = 0,
50 	MCA_IS_GLOBAL = 1
51 } mca_type_t;
52 
53 #define MAX_PAGE_ISOLATE 1024
54 
55 static struct page *page_isolate[MAX_PAGE_ISOLATE];
56 static int num_page_isolate = 0;
57 
58 typedef enum {
59 	ISOLATE_NG,
60 	ISOLATE_OK,
61 	ISOLATE_NONE
62 } isolate_status_t;
63 
64 typedef enum {
65 	MCA_NOT_RECOVERED = 0,
66 	MCA_RECOVERED	  = 1
67 } recovery_status_t;
68 
69 /*
70  *  This pool keeps pointers to the section part of SAL error record
71  */
72 static struct {
73 	slidx_list_t *buffer; /* section pointer list pool */
74 	int	     cur_idx; /* Current index of section pointer list pool */
75 	int	     max_idx; /* Maximum index of section pointer list pool */
76 } slidx_pool;
77 
78 static int
79 fatal_mca(const char *fmt, ...)
80 {
81 	va_list args;
82 	char buf[256];
83 
84 	va_start(args, fmt);
85 	vsnprintf(buf, sizeof(buf), fmt, args);
86 	va_end(args);
87 	ia64_mca_printk(KERN_ALERT "MCA: %s\n", buf);
88 
89 	return MCA_NOT_RECOVERED;
90 }
91 
92 static int
93 mca_recovered(const char *fmt, ...)
94 {
95 	va_list args;
96 	char buf[256];
97 
98 	va_start(args, fmt);
99 	vsnprintf(buf, sizeof(buf), fmt, args);
100 	va_end(args);
101 	ia64_mca_printk(KERN_INFO "MCA: %s\n", buf);
102 
103 	return MCA_RECOVERED;
104 }
105 
106 /**
107  * mca_page_isolate - isolate a poisoned page in order not to use it later
108  * @paddr:	poisoned memory location
109  *
110  * Return value:
111  *	one of isolate_status_t, ISOLATE_OK/NG/NONE.
112  */
113 
114 static isolate_status_t
115 mca_page_isolate(unsigned long paddr)
116 {
117 	int i;
118 	struct page *p;
119 
120 	/* whether physical address is valid or not */
121 	if (!ia64_phys_addr_valid(paddr))
122 		return ISOLATE_NONE;
123 
124 	if (!pfn_valid(paddr >> PAGE_SHIFT))
125 		return ISOLATE_NONE;
126 
127 	/* convert physical address to physical page number */
128 	p = pfn_to_page(paddr>>PAGE_SHIFT);
129 
130 	/* check whether a page number have been already registered or not */
131 	for (i = 0; i < num_page_isolate; i++)
132 		if (page_isolate[i] == p)
133 			return ISOLATE_OK; /* already listed */
134 
135 	/* limitation check */
136 	if (num_page_isolate == MAX_PAGE_ISOLATE)
137 		return ISOLATE_NG;
138 
139 	/* kick pages having attribute 'SLAB' or 'Reserved' */
140 	if (PageSlab(p) || PageReserved(p))
141 		return ISOLATE_NG;
142 
143 	/* add attribute 'Reserved' and register the page */
144 	get_page(p);
145 	SetPageReserved(p);
146 	page_isolate[num_page_isolate++] = p;
147 
148 	return ISOLATE_OK;
149 }
150 
151 /**
152  * mca_hanlder_bh - Kill the process which occurred memory read error
153  * @paddr:	poisoned address received from MCA Handler
154  */
155 
156 void
157 mca_handler_bh(unsigned long paddr, void *iip, unsigned long ipsr)
158 {
159 	ia64_mlogbuf_dump();
160 	printk(KERN_ERR "OS_MCA: process [cpu %d, pid: %d, uid: %d, "
161 		"iip: %p, psr: 0x%lx,paddr: 0x%lx](%s) encounters MCA.\n",
162 	       raw_smp_processor_id(), current->pid,
163 		from_kuid(&init_user_ns, current_uid()),
164 		iip, ipsr, paddr, current->comm);
165 
166 	spin_lock(&mca_bh_lock);
167 	switch (mca_page_isolate(paddr)) {
168 	case ISOLATE_OK:
169 		printk(KERN_DEBUG "Page isolation: ( %lx ) success.\n", paddr);
170 		break;
171 	case ISOLATE_NG:
172 		printk(KERN_CRIT "Page isolation: ( %lx ) failure.\n", paddr);
173 		break;
174 	default:
175 		break;
176 	}
177 	spin_unlock(&mca_bh_lock);
178 
179 	/* This process is about to be killed itself */
180 	do_exit(SIGKILL);
181 }
182 
183 /**
184  * mca_make_peidx - Make index of processor error section
185  * @slpi:	pointer to record of processor error section
186  * @peidx:	pointer to index of processor error section
187  */
188 
189 static void
190 mca_make_peidx(sal_log_processor_info_t *slpi, peidx_table_t *peidx)
191 {
192 	/*
193 	 * calculate the start address of
194 	 *   "struct cpuid_info" and "sal_processor_static_info_t".
195 	 */
196 	u64 total_check_num = slpi->valid.num_cache_check
197 				+ slpi->valid.num_tlb_check
198 				+ slpi->valid.num_bus_check
199 				+ slpi->valid.num_reg_file_check
200 				+ slpi->valid.num_ms_check;
201 	u64 head_size =	sizeof(sal_log_mod_error_info_t) * total_check_num
202 			+ sizeof(sal_log_processor_info_t);
203 	u64 mid_size  = slpi->valid.cpuid_info * sizeof(struct sal_cpuid_info);
204 
205 	peidx_head(peidx)   = slpi;
206 	peidx_mid(peidx)    = (struct sal_cpuid_info *)
207 		(slpi->valid.cpuid_info ? ((char*)slpi + head_size) : NULL);
208 	peidx_bottom(peidx) = (sal_processor_static_info_t *)
209 		(slpi->valid.psi_static_struct ?
210 			((char*)slpi + head_size + mid_size) : NULL);
211 }
212 
213 /**
214  * mca_make_slidx -  Make index of SAL error record
215  * @buffer:	pointer to SAL error record
216  * @slidx:	pointer to index of SAL error record
217  *
218  * Return value:
219  *	1 if record has platform error / 0 if not
220  */
221 #define LOG_INDEX_ADD_SECT_PTR(sect, ptr) \
222 	{slidx_list_t *hl = &slidx_pool.buffer[slidx_pool.cur_idx]; \
223 	hl->hdr = ptr; \
224 	list_add(&hl->list, &(sect)); \
225 	slidx_pool.cur_idx = (slidx_pool.cur_idx + 1)%slidx_pool.max_idx; }
226 
227 static int
228 mca_make_slidx(void *buffer, slidx_table_t *slidx)
229 {
230 	int platform_err = 0;
231 	int record_len = ((sal_log_record_header_t*)buffer)->len;
232 	u32 ercd_pos;
233 	int sects;
234 	sal_log_section_hdr_t *sp;
235 
236 	/*
237 	 * Initialize index referring current record
238 	 */
239 	INIT_LIST_HEAD(&(slidx->proc_err));
240 	INIT_LIST_HEAD(&(slidx->mem_dev_err));
241 	INIT_LIST_HEAD(&(slidx->sel_dev_err));
242 	INIT_LIST_HEAD(&(slidx->pci_bus_err));
243 	INIT_LIST_HEAD(&(slidx->smbios_dev_err));
244 	INIT_LIST_HEAD(&(slidx->pci_comp_err));
245 	INIT_LIST_HEAD(&(slidx->plat_specific_err));
246 	INIT_LIST_HEAD(&(slidx->host_ctlr_err));
247 	INIT_LIST_HEAD(&(slidx->plat_bus_err));
248 	INIT_LIST_HEAD(&(slidx->unsupported));
249 
250 	/*
251 	 * Extract a Record Header
252 	 */
253 	slidx->header = buffer;
254 
255 	/*
256 	 * Extract each section records
257 	 * (arranged from "int ia64_log_platform_info_print()")
258 	 */
259 	for (ercd_pos = sizeof(sal_log_record_header_t), sects = 0;
260 		ercd_pos < record_len; ercd_pos += sp->len, sects++) {
261 		sp = (sal_log_section_hdr_t *)((char*)buffer + ercd_pos);
262 		if (!efi_guidcmp(sp->guid, SAL_PROC_DEV_ERR_SECT_GUID)) {
263 			LOG_INDEX_ADD_SECT_PTR(slidx->proc_err, sp);
264 		} else if (!efi_guidcmp(sp->guid,
265 				SAL_PLAT_MEM_DEV_ERR_SECT_GUID)) {
266 			platform_err = 1;
267 			LOG_INDEX_ADD_SECT_PTR(slidx->mem_dev_err, sp);
268 		} else if (!efi_guidcmp(sp->guid,
269 				SAL_PLAT_SEL_DEV_ERR_SECT_GUID)) {
270 			platform_err = 1;
271 			LOG_INDEX_ADD_SECT_PTR(slidx->sel_dev_err, sp);
272 		} else if (!efi_guidcmp(sp->guid,
273 				SAL_PLAT_PCI_BUS_ERR_SECT_GUID)) {
274 			platform_err = 1;
275 			LOG_INDEX_ADD_SECT_PTR(slidx->pci_bus_err, sp);
276 		} else if (!efi_guidcmp(sp->guid,
277 				SAL_PLAT_SMBIOS_DEV_ERR_SECT_GUID)) {
278 			platform_err = 1;
279 			LOG_INDEX_ADD_SECT_PTR(slidx->smbios_dev_err, sp);
280 		} else if (!efi_guidcmp(sp->guid,
281 				SAL_PLAT_PCI_COMP_ERR_SECT_GUID)) {
282 			platform_err = 1;
283 			LOG_INDEX_ADD_SECT_PTR(slidx->pci_comp_err, sp);
284 		} else if (!efi_guidcmp(sp->guid,
285 				SAL_PLAT_SPECIFIC_ERR_SECT_GUID)) {
286 			platform_err = 1;
287 			LOG_INDEX_ADD_SECT_PTR(slidx->plat_specific_err, sp);
288 		} else if (!efi_guidcmp(sp->guid,
289 				SAL_PLAT_HOST_CTLR_ERR_SECT_GUID)) {
290 			platform_err = 1;
291 			LOG_INDEX_ADD_SECT_PTR(slidx->host_ctlr_err, sp);
292 		} else if (!efi_guidcmp(sp->guid,
293 				SAL_PLAT_BUS_ERR_SECT_GUID)) {
294 			platform_err = 1;
295 			LOG_INDEX_ADD_SECT_PTR(slidx->plat_bus_err, sp);
296 		} else {
297 			LOG_INDEX_ADD_SECT_PTR(slidx->unsupported, sp);
298 		}
299 	}
300 	slidx->n_sections = sects;
301 
302 	return platform_err;
303 }
304 
305 /**
306  * init_record_index_pools - Initialize pool of lists for SAL record index
307  *
308  * Return value:
309  *	0 on Success / -ENOMEM on Failure
310  */
311 static int
312 init_record_index_pools(void)
313 {
314 	int i;
315 	int rec_max_size;  /* Maximum size of SAL error records */
316 	int sect_min_size; /* Minimum size of SAL error sections */
317 	/* minimum size table of each section */
318 	static int sal_log_sect_min_sizes[] = {
319 		sizeof(sal_log_processor_info_t)
320 		+ sizeof(sal_processor_static_info_t),
321 		sizeof(sal_log_mem_dev_err_info_t),
322 		sizeof(sal_log_sel_dev_err_info_t),
323 		sizeof(sal_log_pci_bus_err_info_t),
324 		sizeof(sal_log_smbios_dev_err_info_t),
325 		sizeof(sal_log_pci_comp_err_info_t),
326 		sizeof(sal_log_plat_specific_err_info_t),
327 		sizeof(sal_log_host_ctlr_err_info_t),
328 		sizeof(sal_log_plat_bus_err_info_t),
329 	};
330 
331 	/*
332 	 * MCA handler cannot allocate new memory on flight,
333 	 * so we preallocate enough memory to handle a SAL record.
334 	 *
335 	 * Initialize a handling set of slidx_pool:
336 	 *   1. Pick up the max size of SAL error records
337 	 *   2. Pick up the min size of SAL error sections
338 	 *   3. Allocate the pool as enough to 2 SAL records
339 	 *     (now we can estimate the maxinum of section in a record.)
340 	 */
341 
342 	/* - 1 - */
343 	rec_max_size = sal_rec_max;
344 
345 	/* - 2 - */
346 	sect_min_size = sal_log_sect_min_sizes[0];
347 	for (i = 1; i < sizeof sal_log_sect_min_sizes/sizeof(size_t); i++)
348 		if (sect_min_size > sal_log_sect_min_sizes[i])
349 			sect_min_size = sal_log_sect_min_sizes[i];
350 
351 	/* - 3 - */
352 	slidx_pool.max_idx = (rec_max_size/sect_min_size) * 2 + 1;
353 	slidx_pool.buffer =
354 		kmalloc_array(slidx_pool.max_idx, sizeof(slidx_list_t),
355 			      GFP_KERNEL);
356 
357 	return slidx_pool.buffer ? 0 : -ENOMEM;
358 }
359 
360 
361 /*****************************************************************************
362  * Recovery functions                                                        *
363  *****************************************************************************/
364 
365 /**
366  * is_mca_global - Check whether this MCA is global or not
367  * @peidx:	pointer of index of processor error section
368  * @pbci:	pointer to pal_bus_check_info_t
369  * @sos:	pointer to hand off struct between SAL and OS
370  *
371  * Return value:
372  *	MCA_IS_LOCAL / MCA_IS_GLOBAL
373  */
374 
375 static mca_type_t
376 is_mca_global(peidx_table_t *peidx, pal_bus_check_info_t *pbci,
377 	      struct ia64_sal_os_state *sos)
378 {
379 	pal_processor_state_info_t *psp =
380 		(pal_processor_state_info_t*)peidx_psp(peidx);
381 
382 	/*
383 	 * PAL can request a rendezvous, if the MCA has a global scope.
384 	 * If "rz_always" flag is set, SAL requests MCA rendezvous
385 	 * in spite of global MCA.
386 	 * Therefore it is local MCA when rendezvous has not been requested.
387 	 * Failed to rendezvous, the system must be down.
388 	 */
389 	switch (sos->rv_rc) {
390 		case -1: /* SAL rendezvous unsuccessful */
391 			return MCA_IS_GLOBAL;
392 		case  0: /* SAL rendezvous not required */
393 			return MCA_IS_LOCAL;
394 		case  1: /* SAL rendezvous successful int */
395 		case  2: /* SAL rendezvous successful int with init */
396 		default:
397 			break;
398 	}
399 
400 	/*
401 	 * If One or more Cache/TLB/Reg_File/Uarch_Check is here,
402 	 * it would be a local MCA. (i.e. processor internal error)
403 	 */
404 	if (psp->tc || psp->cc || psp->rc || psp->uc)
405 		return MCA_IS_LOCAL;
406 
407 	/*
408 	 * Bus_Check structure with Bus_Check.ib (internal bus error) flag set
409 	 * would be a global MCA. (e.g. a system bus address parity error)
410 	 */
411 	if (!pbci || pbci->ib)
412 		return MCA_IS_GLOBAL;
413 
414 	/*
415 	 * Bus_Check structure with Bus_Check.eb (external bus error) flag set
416 	 * could be either a local MCA or a global MCA.
417 	 *
418 	 * Referring Bus_Check.bsi:
419 	 *   0: Unknown/unclassified
420 	 *   1: BERR#
421 	 *   2: BINIT#
422 	 *   3: Hard Fail
423 	 * (FIXME: Are these SGI specific or generic bsi values?)
424 	 */
425 	if (pbci->eb)
426 		switch (pbci->bsi) {
427 			case 0:
428 				/* e.g. a load from poisoned memory */
429 				return MCA_IS_LOCAL;
430 			case 1:
431 			case 2:
432 			case 3:
433 				return MCA_IS_GLOBAL;
434 		}
435 
436 	return MCA_IS_GLOBAL;
437 }
438 
439 /**
440  * get_target_identifier - Get the valid Cache or Bus check target identifier.
441  * @peidx:	pointer of index of processor error section
442  *
443  * Return value:
444  *	target address on Success / 0 on Failure
445  */
446 static u64
447 get_target_identifier(peidx_table_t *peidx)
448 {
449 	u64 target_address = 0;
450 	sal_log_mod_error_info_t *smei;
451 	pal_cache_check_info_t *pcci;
452 	int i, level = 9;
453 
454 	/*
455 	 * Look through the cache checks for a valid target identifier
456 	 * If more than one valid target identifier, return the one
457 	 * with the lowest cache level.
458 	 */
459 	for (i = 0; i < peidx_cache_check_num(peidx); i++) {
460 		smei = (sal_log_mod_error_info_t *)peidx_cache_check(peidx, i);
461 		if (smei->valid.target_identifier && smei->target_identifier) {
462 			pcci = (pal_cache_check_info_t *)&(smei->check_info);
463 			if (!target_address || (pcci->level < level)) {
464 				target_address = smei->target_identifier;
465 				level = pcci->level;
466 				continue;
467 			}
468 		}
469 	}
470 	if (target_address)
471 		return target_address;
472 
473 	/*
474 	 * Look at the bus check for a valid target identifier
475 	 */
476 	smei = peidx_bus_check(peidx, 0);
477 	if (smei && smei->valid.target_identifier)
478 		return smei->target_identifier;
479 
480 	return 0;
481 }
482 
483 /**
484  * recover_from_read_error - Try to recover the errors which type are "read"s.
485  * @slidx:	pointer of index of SAL error record
486  * @peidx:	pointer of index of processor error section
487  * @pbci:	pointer of pal_bus_check_info
488  * @sos:	pointer to hand off struct between SAL and OS
489  *
490  * Return value:
491  *	1 on Success / 0 on Failure
492  */
493 
494 static int
495 recover_from_read_error(slidx_table_t *slidx,
496 			peidx_table_t *peidx, pal_bus_check_info_t *pbci,
497 			struct ia64_sal_os_state *sos)
498 {
499 	u64 target_identifier;
500 	pal_min_state_area_t *pmsa;
501 	struct ia64_psr *psr1, *psr2;
502 	ia64_fptr_t *mca_hdlr_bh = (ia64_fptr_t*)mca_handler_bhhook;
503 
504 	/* Is target address valid? */
505 	target_identifier = get_target_identifier(peidx);
506 	if (!target_identifier)
507 		return fatal_mca("target address not valid");
508 
509 	/*
510 	 * cpu read or memory-mapped io read
511 	 *
512 	 *    offending process  affected process  OS MCA do
513 	 *     kernel mode        kernel mode       down system
514 	 *     kernel mode        user   mode       kill the process
515 	 *     user   mode        kernel mode       down system (*)
516 	 *     user   mode        user   mode       kill the process
517 	 *
518 	 * (*) You could terminate offending user-mode process
519 	 *    if (pbci->pv && pbci->pl != 0) *and* if you sure
520 	 *    the process not have any locks of kernel.
521 	 */
522 
523 	/* Is minstate valid? */
524 	if (!peidx_bottom(peidx) || !(peidx_bottom(peidx)->valid.minstate))
525 		return fatal_mca("minstate not valid");
526 	psr1 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_ipsr);
527 	psr2 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_xpsr);
528 
529 	/*
530 	 *  Check the privilege level of interrupted context.
531 	 *   If it is user-mode, then terminate affected process.
532 	 */
533 
534 	pmsa = sos->pal_min_state;
535 	if (psr1->cpl != 0 ||
536 	   ((psr2->cpl != 0) && mca_recover_range(pmsa->pmsa_iip))) {
537 		/*
538 		 *  setup for resume to bottom half of MCA,
539 		 * "mca_handler_bhhook"
540 		 */
541 		/* pass to bhhook as argument (gr8, ...) */
542 		pmsa->pmsa_gr[8-1] = target_identifier;
543 		pmsa->pmsa_gr[9-1] = pmsa->pmsa_iip;
544 		pmsa->pmsa_gr[10-1] = pmsa->pmsa_ipsr;
545 		/* set interrupted return address (but no use) */
546 		pmsa->pmsa_br0 = pmsa->pmsa_iip;
547 		/* change resume address to bottom half */
548 		pmsa->pmsa_iip = mca_hdlr_bh->fp;
549 		pmsa->pmsa_gr[1-1] = mca_hdlr_bh->gp;
550 		/* set cpl with kernel mode */
551 		psr2 = (struct ia64_psr *)&pmsa->pmsa_ipsr;
552 		psr2->cpl = 0;
553 		psr2->ri  = 0;
554 		psr2->bn  = 1;
555 		psr2->i  = 0;
556 
557 		return mca_recovered("user memory corruption. "
558 				"kill affected process - recovered.");
559 	}
560 
561 	return fatal_mca("kernel context not recovered, iip 0x%lx\n",
562 			 pmsa->pmsa_iip);
563 }
564 
565 /**
566  * recover_from_platform_error - Recover from platform error.
567  * @slidx:	pointer of index of SAL error record
568  * @peidx:	pointer of index of processor error section
569  * @pbci:	pointer of pal_bus_check_info
570  * @sos:	pointer to hand off struct between SAL and OS
571  *
572  * Return value:
573  *	1 on Success / 0 on Failure
574  */
575 
576 static int
577 recover_from_platform_error(slidx_table_t *slidx, peidx_table_t *peidx,
578 			    pal_bus_check_info_t *pbci,
579 			    struct ia64_sal_os_state *sos)
580 {
581 	int status = 0;
582 	pal_processor_state_info_t *psp =
583 		(pal_processor_state_info_t*)peidx_psp(peidx);
584 
585 	if (psp->bc && pbci->eb && pbci->bsi == 0) {
586 		switch(pbci->type) {
587 		case 1: /* partial read */
588 		case 3: /* full line(cpu) read */
589 		case 9: /* I/O space read */
590 			status = recover_from_read_error(slidx, peidx, pbci,
591 							 sos);
592 			break;
593 		case 0: /* unknown */
594 		case 2: /* partial write */
595 		case 4: /* full line write */
596 		case 5: /* implicit or explicit write-back operation */
597 		case 6: /* snoop probe */
598 		case 7: /* incoming or outgoing ptc.g */
599 		case 8: /* write coalescing transactions */
600 		case 10: /* I/O space write */
601 		case 11: /* inter-processor interrupt message(IPI) */
602 		case 12: /* interrupt acknowledge or
603 				external task priority cycle */
604 		default:
605 			break;
606 		}
607 	} else if (psp->cc && !psp->bc) {	/* Cache error */
608 		status = recover_from_read_error(slidx, peidx, pbci, sos);
609 	}
610 
611 	return status;
612 }
613 
614 /*
615  * recover_from_tlb_check
616  * @peidx:	pointer of index of processor error section
617  *
618  * Return value:
619  *	1 on Success / 0 on Failure
620  */
621 static int
622 recover_from_tlb_check(peidx_table_t *peidx)
623 {
624 	sal_log_mod_error_info_t *smei;
625 	pal_tlb_check_info_t *ptci;
626 
627 	smei = (sal_log_mod_error_info_t *)peidx_tlb_check(peidx, 0);
628 	ptci = (pal_tlb_check_info_t *)&(smei->check_info);
629 
630 	/*
631 	 * Look for signature of a duplicate TLB DTC entry, which is
632 	 * a SW bug and always fatal.
633 	 */
634 	if (ptci->op == PAL_TLB_CHECK_OP_PURGE
635 	    && !(ptci->itr || ptci->dtc || ptci->itc))
636 		return fatal_mca("Duplicate TLB entry");
637 
638 	return mca_recovered("TLB check recovered");
639 }
640 
641 /**
642  * recover_from_processor_error
643  * @platform:	whether there are some platform error section or not
644  * @slidx:	pointer of index of SAL error record
645  * @peidx:	pointer of index of processor error section
646  * @pbci:	pointer of pal_bus_check_info
647  * @sos:	pointer to hand off struct between SAL and OS
648  *
649  * Return value:
650  *	1 on Success / 0 on Failure
651  */
652 
653 static int
654 recover_from_processor_error(int platform, slidx_table_t *slidx,
655 			     peidx_table_t *peidx, pal_bus_check_info_t *pbci,
656 			     struct ia64_sal_os_state *sos)
657 {
658 	pal_processor_state_info_t *psp =
659 		(pal_processor_state_info_t*)peidx_psp(peidx);
660 
661 	/*
662 	 * Processor recovery status must key off of the PAL recovery
663 	 * status in the Processor State Parameter.
664 	 */
665 
666 	/*
667 	 * The machine check is corrected.
668 	 */
669 	if (psp->cm == 1)
670 		return mca_recovered("machine check is already corrected.");
671 
672 	/*
673 	 * The error was not contained.  Software must be reset.
674 	 */
675 	if (psp->us || psp->ci == 0)
676 		return fatal_mca("error not contained");
677 
678 	/*
679 	 * Look for recoverable TLB check
680 	 */
681 	if (psp->tc && !(psp->cc || psp->bc || psp->rc || psp->uc))
682 		return recover_from_tlb_check(peidx);
683 
684 	/*
685 	 * The cache check and bus check bits have four possible states
686 	 *   cc bc
687 	 *    1  1	Memory error, attempt recovery
688 	 *    1  0	Cache error, attempt recovery
689 	 *    0  1	I/O error, attempt recovery
690 	 *    0  0	Other error type, not recovered
691 	 */
692 	if (psp->cc == 0 && (psp->bc == 0 || pbci == NULL))
693 		return fatal_mca("No cache or bus check");
694 
695 	/*
696 	 * Cannot handle more than one bus check.
697 	 */
698 	if (peidx_bus_check_num(peidx) > 1)
699 		return fatal_mca("Too many bus checks");
700 
701 	if (pbci->ib)
702 		return fatal_mca("Internal Bus error");
703 	if (pbci->eb && pbci->bsi > 0)
704 		return fatal_mca("External bus check fatal status");
705 
706 	/*
707 	 * This is a local MCA and estimated as a recoverable error.
708 	 */
709 	if (platform)
710 		return recover_from_platform_error(slidx, peidx, pbci, sos);
711 
712 	/*
713 	 * On account of strange SAL error record, we cannot recover.
714 	 */
715 	return fatal_mca("Strange SAL record");
716 }
717 
718 /**
719  * mca_try_to_recover - Try to recover from MCA
720  * @rec:	pointer to a SAL error record
721  * @sos:	pointer to hand off struct between SAL and OS
722  *
723  * Return value:
724  *	1 on Success / 0 on Failure
725  */
726 
727 static int
728 mca_try_to_recover(void *rec, struct ia64_sal_os_state *sos)
729 {
730 	int platform_err;
731 	int n_proc_err;
732 	slidx_table_t slidx;
733 	peidx_table_t peidx;
734 	pal_bus_check_info_t pbci;
735 
736 	/* Make index of SAL error record */
737 	platform_err = mca_make_slidx(rec, &slidx);
738 
739 	/* Count processor error sections */
740 	n_proc_err = slidx_count(&slidx, proc_err);
741 
742 	 /* Now, OS can recover when there is one processor error section */
743 	if (n_proc_err > 1)
744 		return fatal_mca("Too Many Errors");
745 	else if (n_proc_err == 0)
746 		/* Weird SAL record ... We can't do anything */
747 		return fatal_mca("Weird SAL record");
748 
749 	/* Make index of processor error section */
750 	mca_make_peidx((sal_log_processor_info_t*)
751 		slidx_first_entry(&slidx.proc_err)->hdr, &peidx);
752 
753 	/* Extract Processor BUS_CHECK[0] */
754 	*((u64*)&pbci) = peidx_check_info(&peidx, bus_check, 0);
755 
756 	/* Check whether MCA is global or not */
757 	if (is_mca_global(&peidx, &pbci, sos))
758 		return fatal_mca("global MCA");
759 
760 	/* Try to recover a processor error */
761 	return recover_from_processor_error(platform_err, &slidx, &peidx,
762 					    &pbci, sos);
763 }
764 
765 /*
766  * =============================================================================
767  */
768 
769 int __init mca_external_handler_init(void)
770 {
771 	if (init_record_index_pools())
772 		return -ENOMEM;
773 
774 	/* register external mca handlers */
775 	if (ia64_reg_MCA_extension(mca_try_to_recover)) {
776 		printk(KERN_ERR "ia64_reg_MCA_extension failed.\n");
777 		kfree(slidx_pool.buffer);
778 		return -EFAULT;
779 	}
780 	return 0;
781 }
782 
783 void __exit mca_external_handler_exit(void)
784 {
785 	/* unregister external mca handlers */
786 	ia64_unreg_MCA_extension();
787 	kfree(slidx_pool.buffer);
788 }
789 
790 module_init(mca_external_handler_init);
791 module_exit(mca_external_handler_exit);
792 
793 module_param(sal_rec_max, int, 0644);
794 MODULE_PARM_DESC(sal_rec_max, "Max size of SAL error record");
795 
796 MODULE_DESCRIPTION("ia64 platform dependent mca handler driver");
797 MODULE_LICENSE("GPL");
798