Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 796 insertions, 0 deletions

diff --git a/arch/ia64/kernel/mca_drv.c b/arch/ia64/kernel/mca_drv.c
new file mode 100644
index 000000000..06419a95a
--- /dev/null
+++ b/arch/ia64/kernel/mca_drv.c
@@ -0,0 +1,796 @@
+/*
+ * File:	mca_drv.c
+ * Purpose:	Generic MCA handling layer
+ *
+ * Copyright (C) 2004 FUJITSU LIMITED
+ * Copyright (C) 2004 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/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 <linux/slab.h>
+
+#include <asm/delay.h>
+#include <asm/machvec.h>
+#include <asm/page.h>
+#include <asm/ptrace.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,
+		from_kuid(&init_user_ns, 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 < ARRAY_SIZE(sal_log_sect_min_sizes); 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 =
+		kmalloc_array(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 Failure
+ */
+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 recoverable 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");