From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753410Ab0JCOo2 (ORCPT ); Sun, 3 Oct 2010 10:44:28 -0400 Received: from terminus.zytor.com ([198.137.202.10]:35217 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253Ab0JCOo1 (ORCPT ); Sun, 3 Oct 2010 10:44:27 -0400 Message-ID: <4CA89681.8000202@zytor.com> Date: Sun, 03 Oct 2010 07:43:13 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc13 Thunderbird/3.1.4 MIME-Version: 1.0 To: Borislav Petkov , Ingo Molnar , Thomas Gleixner , lkml Subject: Re: NOPL on 32-bit References: <20101003093701.GB3733@liondog.tnic> In-Reply-To: <20101003093701.GB3733@liondog.tnic> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/03/2010 02:37 AM, Borislav Petkov wrote: > Hi, > > it looks like we currently clear X86_FEATURE_NOPL in detect_nopl() > unconditionally and not only on 32-bit, as it should be according to > ba0593bf553c450a03dbc5f8c1f0ff58b778a0c8. > > I'm thinking maybe something like the following might be in order > > -- > diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c > index caa967d..9a2cfeb 100644 > --- a/arch/x86/kernel/cpu/common.c > +++ b/arch/x86/kernel/cpu/common.c > @@ -713,7 +713,9 @@ void __init early_cpu_init(void) > */ > static void __cpuinit detect_nopl(struct cpuinfo_x86 *c) > { > +#ifdef CONFIG_X86_32 > clear_cpu_cap(c, X86_FEATURE_NOPL); > +#endif > } > > static void __cpuinit generic_identify(struct cpuinfo_x86 *c) > -- > Yes, that's a bug. It should be disabled only on 32 bits. -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.