From aedbdeab00dcfcc6d751f9fb1b4896b01911d494 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 4 Apr 2020 15:39:13 +0200 Subject: [PATCH] x86/mce: Use untraced rd/wrmsr in the MCE offline/crash check mce_check_crashing_cpu() is called right at the entry of the MCE handler. It uses mce_rdmsr() and mce_wrmsr() which are wrappers around rdmsr() and wrmsr() to handle the MCE error injection mechanism, which is pointless in this context, i.e. when the MCE hits an offline CPU or the system is already marked crashing. The MSR access can also be traced, so use the untraceable variants. This is also safe vs. XEN paravirt as these MSRs are not affected by XEN PV modifications. Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Peter Zijlstra Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505135314.426347351@linutronix.de --- arch/x86/kernel/cpu/mce/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 842dd03..3177652 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -1108,7 +1108,7 @@ static noinstr bool mce_check_crashing_cpu(void) (crashing_cpu != -1 && crashing_cpu != cpu)) { u64 mcgstatus; - mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS); + mcgstatus = __rdmsr(MSR_IA32_MCG_STATUS); if (boot_cpu_data.x86_vendor == X86_VENDOR_ZHAOXIN) { if (mcgstatus & MCG_STATUS_LMCES) @@ -1116,7 +1116,7 @@ static noinstr bool mce_check_crashing_cpu(void) } if (mcgstatus & MCG_STATUS_RIPV) { - mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); + __wrmsr(MSR_IA32_MCG_STATUS, 0, 0); return true; } } -- 2.7.4