From 973a2dd1d50a11d380086601f14e59116f93e8c5 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 12 Feb 2009 13:39:32 +0100 Subject: [PATCH] x86, mce: disable machine checks on suspend Impact: Bug fix During suspend it is not reliable to process machine check exceptions, because CPUs disappear but can still get machine check broadcasts. Also the system is slightly more likely to machine check them, but the handler is typically not a position to handle them in a meaningfull way. So disable them during suspend and enable them during resume. Also make sure they are always disabled on hot-unplugged CPUs. This new code assumes that suspend always hotunplugs all non BP CPUs. v2: Remove the WARN_ONs Thomas objected to. Signed-off-by: Andi Kleen Acked-by: Thomas Gleixner Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/mcheck/mce_64.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/x86/kernel/cpu/mcheck/mce_64.c b/arch/x86/kernel/cpu/mcheck/mce_64.c index 25cf624eccb7..5ed80991ab9e 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_64.c +++ b/arch/x86/kernel/cpu/mcheck/mce_64.c @@ -728,6 +728,29 @@ __setup("mce=", mcheck_enable); * Sysfs support */ +/* + * Disable machine checks on suspend and shutdown. We can't really handle + * them later. + */ +static int mce_disable(void) +{ + int i; + + for (i = 0; i < banks; i++) + wrmsrl(MSR_IA32_MC0_CTL + i*4, 0); + return 0; +} + +static int mce_suspend(struct sys_device *dev, pm_message_t state) +{ + return mce_disable(); +} + +static int mce_shutdown(struct sys_device *dev) +{ + return mce_disable(); +} + /* On resume clear all MCE state. Don't want to see leftovers from the BIOS. Only one CPU is active at this time, the others get readded later using CPU hotplug. */ @@ -752,6 +775,8 @@ static void mce_restart(void) } static struct sysdev_class mce_sysclass = { + .suspend = mce_suspend, + .shutdown = mce_shutdown, .resume = mce_resume, .name = "machinecheck", }; -- 2.39.5