Hi Borislav, Tony,
On 2017/11/15 18:33, Borislav Petkov wrote:
> On Wed, Nov 15, 2017 at 02:44:07AM +0000, Luck, Tony wrote:
>> This code is subtle :-(
>
> I'm glad that we agree on this! :-)
>
> Anyone wanting to rewrite it yet?
>
In Intel SDM Volume 3B (253669-063US, July 2017), SRAO could 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).
As the description in SDM, I think this flag could be used to determine whether
MCE or CMC was triggered. So we could merge this two case in one and just
remove the S=0 check for SRAO.
How about this patch?
>From a06b2a781a86e3b1fe241591b53f7a6d33d63331 Mon Sep 17 00:00:00 2001
From: Xie XiuQi <xiexi...@huawei.com>
Date: Tue, 14 Nov 2017 10:13:22 +0800
Subject: [PATCH] x86/mce: add support SRAO reported via CMC check
In Intel SDM Volume 3B (253669-063US, July 2017), SRAO could 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 we could merge this two case, and just remove the S=0 check for SRAO
in mce_severity().
Signed-off-by: Xie XiuQi <xiexi...@huawei.com>
Tested-by: Chen Wei <chenwe...@huawei.com>
---
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 4ca632a..5bbd06f 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-severity.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c
@@ -59,6 +59,7 @@
#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 @@
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 @@
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)
--
1.8.3.1
