From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760699AbXFAAoV (ORCPT ); Thu, 31 May 2007 20:44:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757298AbXFAAoN (ORCPT ); Thu, 31 May 2007 20:44:13 -0400 Received: from smtp1.linux-foundation.org ([207.189.120.13]:55571 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756339AbXFAAoM (ORCPT ); Thu, 31 May 2007 20:44:12 -0400 Date: Thu, 31 May 2007 17:43:55 -0700 From: Andrew Morton To: Mikael Pettersson Cc: mathieu.desnoyers@polymtl.ca, linux-kernel@vger.kernel.org Subject: Re: [patch 8/9] F00F bug fixup for i386 - use conditional calls Message-Id: <20070531174355.544e7588.akpm@linux-foundation.org> In-Reply-To: <200706010014.l510ErWa022252@harpo.it.uu.se> References: <200706010014.l510ErWa022252@harpo.it.uu.se> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 1 Jun 2007 02:14:53 +0200 (MEST) Mikael Pettersson wrote: > Andrew Morton wrote: > > Mathieu Desnoyers wrote: > > > > > * Andrew Morton (akpm@linux-foundation.org) wrote: > > > > > > > > Use the faster conditional calls for F00F bug handling in do_page_fault. > > > > > > > > > > > > > I guess this means that CONDCALL will be enabled on pretty much all i386, > > > > in which case making the whole feature Kconfigurable is starting to look > > > > marginal. > > > > > > > > Perhaps a better approach would have to made this change dependent upon > > > > CONDCALL, rather than forcing it on. > > > > > > > > > > Do you mean making X86_F00F_BUG depend on COND_CALL instead of selecting > > > it ? > > > > yup > > X86_F00F_BUG needs to be enabled in all kernels capable of booting on > P5 class machines, whether or not some obscure CONFIG_COND_CALL thingy > is enabled or not. X86_F00F_BUG is not some optional optimisation, it's > an essential workaround for a serious hardware bug. > > Therefore it seems select rather than depend is called for. Nope. CONFIG_COND_CALL=n -> do f00f handling the present way CONFIG_COND_CALL=y -> do f00f handling the new, fast-n-fancy way Because I don't think everyone will want to drag all this cond_call stuff into their kernel just for slightly faster f00f handling.