From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754185AbYIEUP6 (ORCPT ); Fri, 5 Sep 2008 16:15:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751608AbYIEUPu (ORCPT ); Fri, 5 Sep 2008 16:15:50 -0400 Received: from terminus.zytor.com ([198.137.202.10]:39648 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002AbYIEUPt (ORCPT ); Fri, 5 Sep 2008 16:15:49 -0400 Message-ID: <48C19296.6020201@zytor.com> Date: Fri, 05 Sep 2008 13:12:06 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Jan Beulich CC: linux@sandersweb.net, Ingo Molnar , Andi Kleen , Arjan van de Ven , Thomas Gleixner , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [BUG] x86 kenel won't boot under Virtual PC References: <200808311422.12525.linux@sandersweb.net> <20080831122751.72afafb5@infradead.org> <200809051138.20615.linux@sandersweb.net> <48C17754.76E4.0078.0@novell.com> In-Reply-To: <48C17754.76E4.0078.0@novell.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jan Beulich wrote: > > I disagree here: If I configure a 686+ kernel, I expect these NOPs to be > that way (and to work). If you want to run on something that's not > compliant, you just shouldn't configure your kernel that way. > Okay, we do not generate P6 NOPs statically if CONFIG_X86_GENERIC_CPU is enabled -- unless, of course gcc/binutils generates them, which they now do for certain CPU types. If you are selecting a specific CPU *and* you don't select GENERIC, you should get valid code for the selected CPU only. As far as using them dynamically, there is code in -tip that determines dynamically and explicitly if the long NOPs are available, and only uses them if they are. -hpa