linux-kernel - Re: [PATCH] x86/mce: Don't disable MCA banks when offlining a CPU on AMD systems

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Date:   Mon, 5 Jun 2017 22:10:22 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Yazen Ghannam <Yazen.Ghannam@....com>
Cc:     linux-edac@...r.kernel.org, Tony Luck <tony.luck@...el.com>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/mce: Don't disable MCA banks when offlining a CPU on
 AMD systems

On Mon, Jun 05, 2017 at 02:53:47PM -0500, Yazen Ghannam wrote:
> From: Yazen Ghannam <yazen.ghannam@....com>
> 
> AMD systems have non-core, shared MCA banks within a Die. These banks are
> controlled by a master CPU per Die. If this CPU is offlined then all the
> shared banks are disabled in addition to the CPU's core banks.
> 
> Also, Fam17h systems may have SMT enabled. The MCA_CTL register is shared
> between SMT thread siblings. If a CPU is offlined then all its sibling's
> MCA banks are also disabled.
> 
> Do a vendor check for AMD and return early when offling a CPU.
> 
> Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>
> ---
>  arch/x86/kernel/cpu/mcheck/mce.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index 5cfbaeb..e317a95 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1917,7 +1917,8 @@ static void vendor_disable_error_reporting(void)
>  	 * inhibit reporting for all shared resources on the socket like the
>  	 * last level cache (LLC), the integrated memory controller (iMC), etc.
>  	 */
> -	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
> +	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL ||
> +	    boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
>  		return;
>  
>  	mce_disable_error_reporting();
> -- 

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

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