linux-kernel - [PATCH] x86/mce: Do not use bank 1 for APEI generated error logs.

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Date:	Fri, 27 May 2016 14:11:06 -0700
From:	Tony Luck <tony.luck@...el.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
	Aristeu Rozanski <arozansk@...hat.com>
Subject: [PATCH] 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 "mca_cfg.banks" (one higher than the largest bank number
supported on the platform) so that it will be clearer that this error
did not originate in a machine check bank.

Signed-off-by: Tony Luck <tony.luck@...el.com>
---
 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 34c89a3e8260..9d2c02337713 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 = mca_cfg.banks;
 	/* Fake a memory read error with unknown channel */
 	m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV | 0x9f;

-- 
2.5.0