From d5172f263f76ca6d588f533c0989b22521fcbac2 Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@muc.de>
Date: Sun, 7 Aug 2005 09:42:07 -0700
Subject: [PATCH] x86_64: ignore machine checks from boot time
Don't log machine check events left over from boot. Too many BIOSes leave
bogus events in there.
This unfortunately also makes it impossible to log events that caused a
reboot. For people with non broken BIOS there is mce=bootlog
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
arch/x86_64/kernel/mce.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
(limited to 'arch')
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c
index 3b267c91bb..8aa56736cd 100644
--- a/arch/x86_64/kernel/mce.c
+++ b/arch/x86_64/kernel/mce.c
@@ -36,6 +36,7 @@ static unsigned long bank[NR_BANKS] = { [0 ... NR_BANKS-1] = ~0UL };
static unsigned long console_logged;
static int notify_user;
static int rip_msr;
+static int mce_bootlog;
/*
* Lockless MCE logging infrastructure.
@@ -197,10 +198,11 @@ void do_machine_check(struct pt_regs * regs, long error_code)
rdmsrl(MSR_IA32_MC0_ADDR + i*4, m.addr);
mce_get_rip(&m, regs);
- if (error_code != -1)
+ if (error_code >= 0)
rdtscll(m.tsc);
wrmsrl(MSR_IA32_MC0_STATUS + i*4, 0);
- mce_log(&m);
+ if (error_code != -2)
+ mce_log(&m);
/* Did this bank cause the exception? */
/* Assume that the bank with uncorrectable errors did it,
@@ -315,7 +317,7 @@ static void mce_init(void *dummy)
/* Log the machine checks left over from the previous reset.
This also clears all registers */
- do_machine_check(NULL, -1);
+ do_machine_check(NULL, mce_bootlog ? -1 : -2);
set_in_cr4(X86_CR4_MCE);
@@ -476,11 +478,17 @@ static int __init mcheck_disable(char *str)
}
/* mce=off disables machine check. Note you can reenable it later
- using sysfs */
+ using sysfs.
+ mce=bootlog Log MCEs from before booting. Disabled by default to work
+ around buggy BIOS that leave bogus MCEs. */
static int __init mcheck_enable(char *str)
{
+ if (*str == '=')
+ str++;
if (!strcmp(str, "off"))
mce_dont_init = 1;
+ else if (!strcmp(str, "bootlog"))
+ mce_bootlog = 1;
else
printk("mce= argument %s ignored. Please use /sys", str);
return 0;
--
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