Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756132AbbBFQNn (ORCPT ); Fri, 6 Feb 2015 11:13:43 -0500 Received: from mail.skyhub.de ([78.46.96.112]:34557 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751964AbbBFQNl (ORCPT ); Fri, 6 Feb 2015 11:13:41 -0500 Date: Fri, 6 Feb 2015 17:13:10 +0100 From: Borislav Petkov To: Scotty Bauer Cc: tglx@linutronix.de, mingo@redheat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, x86@kernel.org Subject: [PATCH] x86, smpboot: Call CLFLUSH only on X86_BUG_CLFLUSH_MONITOR-affected CPUs Message-ID: <20150206161310.GG3220@pd.tnic> References: <54CBF6F9.5040508@eng.utah.edu> <20150130233142.GA1884@pd.tnic> <20150206160547.GF3220@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150206160547.GF3220@pd.tnic> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1357 Lines: 46 From: Borislav Petkov Subject: [PATCH] x86, smpboot: Call CLFLUSH only on X86_BUG_CLFLUSH_MONITOR-affected CPUs Make the AAI65 erratum workaround for Xeon 7400 machines only instead of punishing all CPUs doing idle with MWAIT with the CLFLUSH penalty. Based on a patch originally by Scotty Bauer . Cc: Scotty Bauer Signed-off-by: Borislav Petkov --- arch/x86/kernel/smpboot.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 6d7022c683e3..771ebd6e8b77 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1432,7 +1432,11 @@ static inline void mwait_play_dead(void) * case where we return around the loop. */ mb(); - clflush(mwait_ptr); + + asm volatile(ALTERNATIVE("", "clflush %[p]", + X86_BUG_CLFLUSH_MONITOR) + : [p] "+m" (*(unsigned long *)mwait_ptr)); + mb(); __monitor(mwait_ptr, 0, 0); mb(); -- 2.2.0.33.gc18b867 -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/