linux-kernel - [PATCH tip:ras/core 1/2] x86/MCE: Extend table to report action optional errors through CMCI too

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Message-Id: <20171204165438.25048-1-bp@alien8.de>
Date:   Mon,  4 Dec 2017 17:54:37 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        linux-edac <linux-edac@...r.kernel.org>
Subject: [PATCH tip:ras/core 1/2] x86/MCE: Extend table to report action optional errors through CMCI too

From: Xie XiuQi <xiexiuqi@...wei.com>

According to the Intel SDM Volume 3B (253669-063US, July 2017), action
optional (SRAO) errors can be reported either via MCE or CMC:

  In cases when SRAO is signaled via CMCI the error signature is
  indicated via UC=1, PCC=0, S=0.

  Type(*1)	UC	EN	PCC	S	AR	Signaling
  ---------------------------------------------------------------
  UC		1	1	1	x	x	MCE
  SRAR		1	1	0	1	1	MCE
  SRAO		1	x(*2)	0	x(*2)	0	MCE/CMC
  UCNA		1	x	0	0	0	CMC
  CE		0	x	x	x	x	CMC

  NOTES:
  1. SRAR, SRAO and UCNA errors are supported by the processor only
     when IA32_MCG_CAP[24] (MCG_SER_P) is set.
  2. EN=1, S=1 when signaled via MCE. EN=x, S=0 when signaled via CMC.

And there is a description in 15.6.2 UCR Error Reporting and Logging,
for bit S:

  S (Signaling) flag, bit 56 - Indicates (when set) that a machine check
  exception was generated for the UCR error reported in this MC bank...
  When the S flag in the IA32_MCi_STATUS register is clear, this UCR error
  was not signaled via a machine check exception and instead was reported
  as a corrected machine check (CMC).

So merge the two cases and just remove the S=0 check for SRAO in
mce_severity().

Signed-off-by: Xie XiuQi <xiexiuqi@...wei.com>
Reviewed-by: Tony Luck <tony.luck@...el.com>
Tested-by: Chen Wei <chenwei68@...wei.com>
Cc: linux-edac <linux-edac@...r.kernel.org>
Cc: x86-ml <x86@...nel.org>
Link: http://lkml.kernel.org/r/1511575548-41992-1-git-send-email-xiexiuqi@huawei.com
[ Massage commit message. ]
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/cpu/mcheck/mce-severity.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce-severity.c b/arch/x86/kernel/cpu/mcheck/mce-severity.c
index 4ca632a06e0b..5bbd06f38ff6 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-severity.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c
@@ -59,6 +59,7 @@ static struct severity {
 #define  MCGMASK(x, y)	.mcgmask = x, .mcgres = y
 #define  MASK(x, y)	.mask = x, .result = y
 #define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
+#define MCI_UC_AR (MCI_STATUS_UC|MCI_STATUS_AR)
 #define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
 #define	MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
 
@@ -101,6 +102,22 @@ static struct severity {
 		NOSER, BITCLR(MCI_STATUS_UC)
 		),
 
+	/*
+	 * known AO MCACODs reported via MCE or CMC:
+	 *
+	 * SRAO could be signaled either via a machine check exception or
+	 * CMCI with the corresponding bit S 1 or 0. So we don't need to
+	 * check bit S for SRAO.
+	 */
+	MCESEV(
+		AO, "Action optional: memory scrubbing error",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_AR|MCACOD_SCRUBMSK, MCI_STATUS_UC|MCACOD_SCRUB)
+		),
+	MCESEV(
+		AO, "Action optional: last level cache writeback error",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_AR|MCACOD, MCI_STATUS_UC|MCACOD_L3WB)
+		),
+
 	/* ignore OVER for UCNA */
 	MCESEV(
 		UCNA, "Uncorrected no action required",
@@ -149,15 +166,6 @@ static struct severity {
 		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)
 		),
 
-	/* known AO MCACODs: */
-	MCESEV(
-		AO, "Action optional: memory scrubbing error",
-		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD_SCRUBMSK, MCI_UC_S|MCACOD_SCRUB)
-		),
-	MCESEV(
-		AO, "Action optional: last level cache writeback error",
-		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_S|MCACOD_L3WB)
-		),
 	MCESEV(
 		SOME, "Action optional: unknown MCACOD",
 		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S)
-- 
2.13.0