From d5172f263f76ca6d588f533c0989b22521fcbac2 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sun, 7 Aug 2005 09:42:07 -0700 Subject: [PATCH] [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/x86_64/boot-options.txt | 5 +++++ arch/x86_64/kernel/mce.c | 16 ++++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index 476c0c22fbb7..678e8f192db2 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -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 diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c index 3b267c91bb0c..8aa56736cde3 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; -- 2.20.1