linux-kernel - Re: [RESEND][PATCH -tip 3/3] x86, mce: Add new option mce=no_cmci and mce=ignore

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Date:	Mon, 20 Apr 2009 09:31:08 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
Cc:	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
	Andi Kleen <ak@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [RESEND][PATCH -tip 3/3] x86, mce: Add new option mce=no_cmci and mce=ignore_ce

Hidetoshi Seto <seto.hidetoshi@...fujitsu.com> writes:

> This patch introduces a couple of boot option for x86_64 mce.
>
> The "mce=no_cmci" boot option disables cmci feature.
> Since cmci is a new feature so having boot controls to disable
> it will be a help if the hardware is misbehaving.

Acked-by: Andi Kleen <ak@...ux.intel.com>

Although I expect on Nehalem you'll get more problems without CMCI
than with due to the shared banks. Perhaps the documentation
should make that clearer.

>
> The "mce=ignore_ce" boot option disables features for corrected
> errors, i.e. polling timer and cmci.  Usually this disablement
> is not recommended, however it will be a help if there are some
> conflict with the BIOS or hardware monitoring applications etc.

Same problem as with the earlier patch.  You need a point
somewhere where the event is cleared, otherwise all hell
breaks loose.

>  static int mce_dont_init;
> +int cmci_disabled;
> +int ignore_ce;

For global variables you should use a mce_ prefix to not pollute
global name space.

> diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel_64.c b/arch/x86/kernel/cpu/mcheck/mce_intel_64.c
> index d6b72df..64c0dd9 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce_intel_64.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce_intel_64.c
> @@ -109,6 +109,9 @@ static int cmci_supported(int *banks)
>  {
>  	u64 cap;
>  
> +	if (cmci_disabled | ignore_ce)

I presume you meant || here

-Amndi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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