linux-kernel - Re: [PATCH] x86/AMD: Fix Socket ID for LLC topology for AMD Fam17h systems

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Date:   Fri, 2 Sep 2016 10:41:25 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Yazen Ghannam <Yazen.Ghannam@....com>
cc:     mingo@...hat.com, hpa@...or.com, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/AMD: Fix Socket ID for LLC topology for AMD Fam17h
 systems

On Wed, 31 Aug 2016, Yazen Ghannam wrote:

> The Socket ID is ApicId[bits] on Fam17h systems.
> 
> Change substraction to logical AND when extracting socket_id
> from c->apicid.

So Fam17h will only ever have 2 sockets, right?

Thanks,

	tglx

> Signed-off-by: Yazen Ghannam <Yazen.Ghannam@....com>
> ---
>  arch/x86/kernel/cpu/amd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> index f5c69d8..479555f 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -365,7 +365,7 @@ static void amd_detect_cmp(struct cpuinfo_x86 *c)
>  	 if (c->x86 != 0x17 || !cpuid_edx(0x80000006))
>  		return;
>  
> -	socket_id	= (c->apicid >> bits) - 1;
> +	socket_id	= (c->apicid >> bits) & 1;
>  	core_complex_id	= (c->apicid & ((1 << bits) - 1)) >> 3;
>  
>  	per_cpu(cpu_llc_id, cpu) = (socket_id << 3) | core_complex_id;
> -- 
> 1.9.1
> 
>