Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754350AbcKRRDG (ORCPT ); Fri, 18 Nov 2016 12:03:06 -0500 Received: from mga02.intel.com ([134.134.136.20]:8907 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754159AbcKRRDE (ORCPT ); Fri, 18 Nov 2016 12:03:04 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,510,1473145200"; d="scan'208";a="788083273" From: Andi Kleen To: Borislav Petkov Cc: "Luck\, Tony" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] x86/mce: Include the PPIN in machine check records when it is available References: <1479429348-1664-1-git-send-email-tony.luck@intel.com> <1479429348-1664-2-git-send-email-tony.luck@intel.com> <20161118130022.vcnodxrslg6khycc@pd.tnic> Date: Fri, 18 Nov 2016 09:02:56 -0800 In-Reply-To: <20161118130022.vcnodxrslg6khycc@pd.tnic> (Borislav Petkov's message of "Fri, 18 Nov 2016 14:00:22 +0100") Message-ID: <878tsg67r3.fsf@tassilo.jf.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 607 Lines: 20 Borislav Petkov writes: > >> @@ -2134,8 +2140,37 @@ static int __init mcheck_enable(char *str) >> } >> __setup("mce", mcheck_enable); >> >> +static void mcheck_intel_ppin_init(void) > > So this functionality could all be moved to arch/x86/kernel/cpu/intel.c > where you could set an artificial X86_FEATURE_PPIN and get rid of the > have_ppin var. That means that a tiny kernel that compiles out machine check functionality has this unnecessary code. In general it doesn't make any sense to define a FEATURE flag for a single user. It's better to just check it where it is needed. -Andi