linux-kernel - [tip:ras/core] x86/mce: Do not use bank 1 for APEI generated error logs

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Message-ID: <tip-b2de43605410d1970dc9e0f349e399f1d561be13@git.kernel.org>
Date:	Tue, 14 Jun 2016 04:24:57 -0700
From:	tip-bot for Tony Luck <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	bp@...e.de, luto@...capital.net, torvalds@...ux-foundation.org,
	dvlasenk@...hat.com, tglx@...utronix.de, hpa@...or.com,
	linux-kernel@...r.kernel.org, peterz@...radead.org, bp@...en8.de,
	brgerst@...il.com, linux-edac@...r.kernel.org, tony.luck@...el.com,
	mingo@...nel.org, arozansk@...hat.com, mchehab@....samsung.com
Subject: [tip:ras/core] x86/mce: Do not use bank 1 for APEI generated error
 logs

Commit-ID:  b2de43605410d1970dc9e0f349e399f1d561be13
Gitweb:     http://git.kernel.org/tip/b2de43605410d1970dc9e0f349e399f1d561be13
Author:     Tony Luck <tony.luck@...el.com>
AuthorDate: Fri, 27 May 2016 14:11:06 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 14 Jun 2016 10:51:14 +0200

x86/mce: Do not use bank 1 for APEI generated error logs

BIOS can report a memory error to Linux using ACPI/APEI mechanism. When
it does this, we create a fictitious machine check error record and
feed it into the standard mce_log() function. The error record needs a
machine check bank number, and for some reason we chose "1" for this.

But "1" is a valid bank number, and this causes confusion and heartburn
among h/w folks who are concerned that a memory error signature was
somehow logged in bank 1.

Change to use "-1" (field is a "u8" so will typically print as 255).
This should make it clearer that this error did not originate in a
machine check bank.

Signed-off-by: Tony Luck <tony.luck@...el.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Aristeu Rozanski <arozansk@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mauro Carvalho Chehab <mchehab@....samsung.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-edac <linux-edac@...r.kernel.org>
Link: http://lkml.kernel.org/r/b7fffb2b326bc1dd150ffceb9919a803f9496e0e.1464805958.git.tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/cpu/mcheck/mce-apei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce-apei.c b/arch/x86/kernel/cpu/mcheck/mce-apei.c
index 34c89a3..83f1a98 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-apei.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-apei.c
@@ -46,7 +46,7 @@ void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)
 		return;
 
 	mce_setup(&m);
-	m.bank = 1;
+	m.bank = -1;
 	/* Fake a memory read error with unknown channel */
 	m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV | 0x9f;