[PATCH] x86_64: Log machine checks from boot on Intel systems
The logging for boot errors was turned off because it was broken
on some AMD systems. But give Intel EM64T systems a chance because they are
supposed to be correct there.
The advantage is that there is a chance to actually log uncorrected
machine checks after the reset.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index a831396..aaabb58 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -7,10 +7,12 @@
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.
+ Disabled by default on AMD 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.
+ in a reboot. On Intel systems it is enabled by default.
+ mce=nobootlog
+ Disable boot machine check logging.
mce=tolerancelevel (number)
0: always panic, 1: panic if deadlock possible,
2: try to avoid panic, 3: never panic or exit (for testing)
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c
index cf8a76f..183dc61 100644
--- a/arch/x86_64/kernel/mce.c
+++ b/arch/x86_64/kernel/mce.c
@@ -37,7 +37,7 @@
static unsigned long console_logged;
static int notify_user;
static int rip_msr;
-static int mce_bootlog;
+static int mce_bootlog = 1;
/*
* Lockless MCE logging infrastructure.
@@ -347,7 +347,11 @@
/* disable GART TBL walk error reporting, which trips off
incorrectly with the IOMMU & 3ware & Cerberus. */
clear_bit(10, &bank[4]);
+ /* Lots of broken BIOS around that don't clear them
+ by default and leave crap in there. Don't log. */
+ mce_bootlog = 0;
}
+
}
static void __cpuinit mce_cpu_features(struct cpuinfo_x86 *c)
@@ -498,16 +502,16 @@
/* mce=off disables machine check. Note you can reenable it later
using sysfs.
mce=TOLERANCELEVEL (number, see above)
- mce=bootlog Log MCEs from before booting. Disabled by default to work
- around buggy BIOS that leave bogus MCEs. */
+ mce=bootlog Log MCEs from before booting. Disabled by default on AMD.
+ mce=nobootlog Don't log MCEs from before booting. */
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 if (!strcmp(str, "bootlog") || !strcmp(str,"nobootlog"))
+ mce_bootlog = str[0] == 'b';
else if (isdigit(str[0]))
get_option(&str, &tolerant);
else