From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754504Ab0AECSz (ORCPT ); Mon, 4 Jan 2010 21:18:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754256Ab0AECSy (ORCPT ); Mon, 4 Jan 2010 21:18:54 -0500 Received: from ozlabs.org ([203.10.76.45]:51140 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754191Ab0AECSy (ORCPT ); Mon, 4 Jan 2010 21:18:54 -0500 From: Rusty Russell To: Ingo Molnar Subject: [PATCH] Revert "x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium" Date: Tue, 5 Jan 2010 12:48:49 +1030 User-Agent: KMail/1.12.2 (Linux/2.6.31-16-generic; KDE/4.3.2; i686; ; ) Cc: Linus Torvalds , "H. Anvin" , linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <201001051248.49700.rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This reverts commit ae1b22f6e46c03cede7cea234d0bf2253b4261cf. As Linus said in 982d007a6ee: "There was something really messy about cmpxchg8b and clone CPU's, so if you enable it on other CPUs later, do it carefully." This breaks lguest for those configs, but we can fix that by emulating if we have to. Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=14884 Signed-off-by: Rusty Russell Cc: stable@kernel.org --- arch/x86/Kconfig.cpu | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index 08e442b..f20ddf8 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu @@ -396,7 +396,7 @@ config X86_TSC config X86_CMPXCHG64 def_bool y - depends on !M386 && !M486 + depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM # this should be set for all -march=.. options where the compiler # generates cmov.