linux-kernel - [tip: ras/core] x86/mce: Use severity table to handle uncorrected errors in kernel

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Date:   Mon, 31 Oct 2022 16:15:53 -0000
From:   "tip-bot2 for Tony Luck" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Tony Luck <tony.luck@...el.com>, Borislav Petkov <bp@...e.de>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: ras/core] x86/mce: Use severity table to handle uncorrected
 errors in kernel

The following commit has been merged into the ras/core branch of tip:

Commit-ID:     a51cbd0d86d3fa9ecc6ddf186dd1cb66a4fefa87
Gitweb:        https://git.kernel.org/tip/a51cbd0d86d3fa9ecc6ddf186dd1cb66a4fefa87
Author:        Tony Luck <tony.luck@...el.com>
AuthorDate:    Thu, 22 Sep 2022 12:51:35 -07:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Mon, 31 Oct 2022 17:01:19 +01:00

x86/mce: Use severity table to handle uncorrected errors in kernel

mce_severity_intel() has a special case to promote UC and AR errors
in kernel context to PANIC severity.

The "AR" case is already handled with separate entries in the severity
table for all instruction fetch errors, and those data fetch errors that
are not in a recoverable area of the kernel (i.e. have an extable fixup
entry).

Add an entry to the severity table for UC errors in kernel context that
reports severity = PANIC. Delete the special case code from
mce_severity_intel().

Signed-off-by: Tony Luck <tony.luck@...el.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lore.kernel.org/r/20220922195136.54575-2-tony.luck@intel.com
---
 arch/x86/kernel/cpu/mce/severity.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 00483d1..c447716 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -203,6 +203,11 @@ static struct severity {
 		BITSET(MCI_STATUS_OVER|MCI_STATUS_UC)
 		),
 	MCESEV(
+		PANIC, "Uncorrected in kernel",
+		BITSET(MCI_STATUS_UC),
+		KERNEL
+		),
+	MCESEV(
 		UC, "Uncorrected",
 		BITSET(MCI_STATUS_UC)
 		),
@@ -391,9 +396,6 @@ static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs, char 
 			*msg = s->msg;
 		s->covered = 1;
 
-		if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL)
-			return MCE_PANIC_SEVERITY;
-
 		return s->sev;
 	}
 }