[tip:ras/core] x86/mce: Grade uncorrected errors for SMCA-enabled systems

From: tip-bot for Aravind Gopalakrishnan
Date: Tue May 03 2016 - 03:48:34 EST


Commit-ID: 6bda529ec42e1cd4dde1c3d0a1a18000ffd3d419
Gitweb: http://git.kernel.org/tip/6bda529ec42e1cd4dde1c3d0a1a18000ffd3d419
Author: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
AuthorDate: Sat, 30 Apr 2016 14:33:52 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 3 May 2016 08:24:15 +0200

x86/mce: Grade uncorrected errors for SMCA-enabled systems

For upcoming processors with Scalable MCA feature, we need to check the
"succor" CPUID bit and the TCC bit in the MCx_STATUS register in order
to grade an MCE's severity.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
Signed-off-by: Yazen Ghannam <Yazen.Ghannam@xxxxxxx>
[ Simplified code flow, shortened comments. ]
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Aravind Gopalakrishnan <aravindksg.lkml@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1459886686-13977-3-git-send-email-Yazen.Ghannam@xxxxxxx
Link: http://lkml.kernel.org/r/1462019637-16474-3-git-send-email-bp@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/cpu/mcheck/mce-severity.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/arch/x86/kernel/cpu/mcheck/mce-severity.c b/arch/x86/kernel/cpu/mcheck/mce-severity.c
index 5119766..631356c 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-severity.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c
@@ -204,6 +204,33 @@ static int error_context(struct mce *m)
return IN_KERNEL;
}

+static int mce_severity_amd_smca(struct mce *m, int err_ctx)
+{
+ u32 addr = MSR_AMD64_SMCA_MCx_CONFIG(m->bank);
+ u32 low, high;
+
+ /*
+ * We need to look at the following bits:
+ * - "succor" bit (data poisoning support), and
+ * - TCC bit (Task Context Corrupt)
+ * in MCi_STATUS to determine error severity.
+ */
+ if (!mce_flags.succor)
+ return MCE_PANIC_SEVERITY;
+
+ if (rdmsr_safe(addr, &low, &high))
+ return MCE_PANIC_SEVERITY;
+
+ /* TCC (Task context corrupt). If set and if IN_KERNEL, panic. */
+ if ((low & MCI_CONFIG_MCAX) &&
+ (m->status & MCI_STATUS_TCC) &&
+ (err_ctx == IN_KERNEL))
+ return MCE_PANIC_SEVERITY;
+
+ /* ...otherwise invoke hwpoison handler. */
+ return MCE_AR_SEVERITY;
+}
+
/*
* See AMD Error Scope Hierarchy table in a newer BKDG. For example
* 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features"
@@ -225,6 +252,9 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_exc
* to at least kill process to prolong system operation.
*/
if (mce_flags.overflow_recov) {
+ if (mce_flags.smca)
+ return mce_severity_amd_smca(m, ctx);
+
/* software can try to contain */
if (!(m->mcgstatus & MCG_STATUS_RIPV) && (ctx == IN_KERNEL))
return MCE_PANIC_SEVERITY;