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[PATCH] x86_64: ignore machine checks from boot time

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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>
This commit is contained in:
Andi Kleen 2005-08-07 09:42:07 -07:00 committed by Linus Torvalds
parent cf7bee5a0b
commit d5172f263f
2 changed files with 17 additions and 4 deletions
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5
Documentation/x86_64/boot-options.txt
View file

@ -6,6 +6,11 @@ only the AMD64 specific ones are listed here.
Machine check
mce=off disable machine check
mce=bootlog Enable logging of machine checks left over from booting.
Disabled by default because some BIOS leave bogus ones.
If your BIOS doesn't do that it's a good idea to enable though
to make sure you log even machine check events that result
in a reboot.
nomce (for compatibility with i386): same as mce=off

16
arch/x86_64/kernel/mce.c
View file

@ -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;