From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755296AbYIHSEv (ORCPT ); Mon, 8 Sep 2008 14:04:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753229AbYIHSEl (ORCPT ); Mon, 8 Sep 2008 14:04:41 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38777 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752387AbYIHSEk (ORCPT ); Mon, 8 Sep 2008 14:04:40 -0400 Date: Mon, 8 Sep 2008 11:04:30 -0700 (PDT) From: Linus Torvalds To: "H. Peter Anvin" cc: x86 maintainers , Andrew Morton , Linux Kernel Mailing List Subject: Re: [git pull] x86 fixes In-Reply-To: <200809081752.m88Hq6tn005080@askone.hos.anvin.org> Message-ID: References: <200809081752.m88Hq6tn005080@askone.hos.anvin.org> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 8 Sep 2008, H. Peter Anvin wrote: > > config X86_GENERIC > - bool "Generic x86 support" > + bool "Generic x86 support" if EMBEDDED Ok, so after having realized that this seems to be more about a bug with gcc, I'm really not as convinced any more. As far as I can tell, there are three issues: - "-mtune=core/core2/pentium4/.." is buggy in some gas/gcc versions on x86-32, and makes architectural choices. Any actual _released_ versions? Maybe it's just a current SVN issue? Workaround: don't use it. And yes, X86_GENERIC=y will do that, although quite frankly that seems to be dubious in itself. But quite frankly, it's a gcc bug, and we should see it as such. The better workaround may well be "-Wa,-mtune=generic" as you pointed out. - We do the CONFIG_P6_NOPL thing ourselves, and we should just stop doing that on 32-bit. There simply isn't a good enough reason to do so. I already posteed the Kconfig.cpu patch to just stop doing it. - X86_GENERIC means _other_ things too, like doing a 128-bit cacheline just so that it won't suck horribly on P4's even if it's otherwise tuned for a good microarchitecture. And they really do seem to be _separate_ issues. Do we really want to tie these things together under X86_GENERIC? Linus