linux-kernel - Re: [PATCH v3] x86/mce: Honour bios-set CMCI threshold

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Message-ID: <20121018132456.GB6951@aftab.osrc.amd.com>
Date:	Thu, 18 Oct 2012 15:24:56 +0200
From:	Borislav Petkov <bp@...64.org>
To:	"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
Cc:	"Luck, Tony" <tony.luck@...el.com>, Borislav Petkov <bp@...en8.de>,
	"gong.chen@...ux.intel.com" <gong.chen@...ux.intel.com>,
	"ananth@...ibm.com" <ananth@...ibm.com>,
	"masbock@...ux.vnet.ibm.com" <masbock@...ux.vnet.ibm.com>,
	"x86@...nel.org" <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"lcm@...ibm.com" <lcm@...ibm.com>,
	"andi@...stfloor.org" <andi@...stfloor.org>,
	"hpa@...or.com" <hpa@...or.com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"gregkh@...e.de" <gregkh@...e.de>,
	"linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>
Subject: Re: [PATCH v3] x86/mce: Honour bios-set CMCI threshold

On Thu, Oct 18, 2012 at 11:13:14AM +0530, Naveen N. Rao wrote:
> On 10/17/2012 10:58 PM, Luck, Tony wrote:
> >BUT (squared) do you even really need to know that thresholds were set? You
> >could look at bits {52:38} in the MCi_STATUS information for the bank to see
> >how many corrected errors had been logged.
> 
> Ah, nice. I think we should be able to use this instead of the sysfs
> attribute.

Ok, patch below removes it.

@Tony: I'll send it upwards soonish in case there are no objections.
This way no stable backport will be needed.

Thanks.

--
From: Borislav Petkov <borislav.petkov@....com>
Date: Thu, 18 Oct 2012 15:10:56 +0200
Subject: [PATCH] x86, MCE: Remove bios_cmci_threshold sysfs attribute

450cc201038f3 ("x86/mce: Provide boot argument to honour bios-set CMCI
threshold") added the bios_cmci_threshold attribute which was supposed
to communicate to userspace tools that BIOS CMCI threshold has been
honoured.

However, this info is not of any importance to userspace - rather it
can get the actual error count it has been thresholded already from
MCi_STATUS[38:52].

So drop this before it becomes a used interface (good thing is we caught
this early in 3.7-rc1, right after the merge window closed).

Cc: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
Cc: Tony Luck <tony.luck@...el.com>
Link: http://lkml.kernel.org/r/20121017105940.GA14590@x1.osrc.amd.com
Signed-off-by: Borislav Petkov <borislav.petkov@....com>
---
 arch/x86/kernel/cpu/mcheck/mce.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 29e87d3b2843..46cbf8689692 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -2209,11 +2209,6 @@ static struct dev_ext_attribute dev_attr_cmci_disabled = {
 	&mce_cmci_disabled
 };
 
-static struct dev_ext_attribute dev_attr_bios_cmci_threshold = {
-	__ATTR(bios_cmci_threshold, 0444, device_show_int, NULL),
-	&mce_bios_cmci_threshold
-};
-
 static struct device_attribute *mce_device_attrs[] = {
 	&dev_attr_tolerant.attr,
 	&dev_attr_check_interval.attr,
@@ -2222,7 +2217,6 @@ static struct device_attribute *mce_device_attrs[] = {
 	&dev_attr_dont_log_ce.attr,
 	&dev_attr_ignore_ce.attr,
 	&dev_attr_cmci_disabled.attr,
-	&dev_attr_bios_cmci_threshold.attr,
 	NULL
 };
 
-- 
1.8.0.rc2.4.g42e55a5

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
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