From f32b4f48e3d8f42f01bdd3e5b223de52000288c2 Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Sat, 30 Apr 2016 14:33:57 +0200 Subject: [PATCH] x86/mce: Detect local MCEs properly Orabug: 25384378 Check the MCG_STATUS_LMCES bit on Intel to verify that current MCE is local. It is always local on AMD. Signed-off-by: Yazen Ghannam [ Massaged it a bit. Reflowed comments. Shut up -Wmaybe-uninitialized. ] Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/1462019637-16474-8-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar (cherry picked from commit fead35c68926682c90c995f22b48f1c8d78865c1) Signed-off-by: Somasundaram Krishnasamy Reviewed-by: Jack Vogel --- arch/x86/kernel/cpu/mcheck/mce.c | 33 +++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 80d5fc61ec1f..6dd41e4a326d 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -1030,11 +1030,12 @@ void do_machine_check(struct pt_regs *regs, long error_code) int i; int worst = 0; int severity; + /* * Establish sequential order between the CPUs entering the machine * check handler. */ - int order; + int order = -1; /* * If no_way_out gets set, there is no safe way to recover from this * MCE. If mca_cfg.tolerant is cranked up, we'll try anyway. @@ -1050,7 +1051,12 @@ void do_machine_check(struct pt_regs *regs, long error_code) char *msg = "Unknown"; u64 recover_paddr = ~0ull; int flags = MF_ACTION_REQUIRED; - int lmce = 0; + + /* + * MCEs are always local on AMD. Same is determined by MCG_STATUS_LMCES + * on Intel. + */ + int lmce = 1; /* If this CPU is offline, just bail out. */ if (cpu_is_offline(smp_processor_id())) { @@ -1089,19 +1095,20 @@ void do_machine_check(struct pt_regs *regs, long error_code) kill_it = 1; /* - * Check if this MCE is signaled to only this logical processor + * Check if this MCE is signaled to only this logical processor, + * on Intel only. */ - if (m.mcgstatus & MCG_STATUS_LMCES) - lmce = 1; - else { - /* - * Go through all the banks in exclusion of the other CPUs. - * This way we don't report duplicated events on shared banks - * because the first one to see it will clear it. - * If this is a Local MCE, then no need to perform rendezvous. - */ + if (m.cpuvendor == X86_VENDOR_INTEL) + lmce = m.mcgstatus & MCG_STATUS_LMCES; + + /* + * Go through all banks in exclusion of the other CPUs. This way we + * don't report duplicated events on shared banks because the first one + * to see it will clear it. If this is a Local MCE, then no need to + * perform rendezvous. + */ + if (!lmce) order = mce_start(&no_way_out); - } for (i = 0; i < cfg->banks; i++) { __clear_bit(i, toclear); -- 2.50.1