From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754189AbYKFVui (ORCPT ); Thu, 6 Nov 2008 16:50:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753986AbYKFVty (ORCPT ); Thu, 6 Nov 2008 16:49:54 -0500 Received: from pfepa.post.tele.dk ([195.41.46.235]:55958 "EHLO pfepa.post.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753955AbYKFVtw (ORCPT ); Thu, 6 Nov 2008 16:49:52 -0500 Date: Thu, 6 Nov 2008 22:48:48 +0100 From: Sam Ravnborg To: Jeremy Fitzhardinge Cc: Takashi Iwai , Tony Luck , Isaku Yamahata , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix section type conflict in arch/ia64/xen/xen_pv_ops.c Message-ID: <20081106214848.GA3579@uranus.ravnborg.org> References: <49133E11.8050607@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49133E11.8050607@goop.org> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 06, 2008 at 10:57:21AM -0800, Jeremy Fitzhardinge wrote: > Takashi Iwai wrote: > >__initdata and const cannot be always a happy pair, as gcc-4.3.3 gives > >the compile errors like: > > > > arch/ia64/xen/xen_pv_ops.c:156: error: xen_init_ops causes a section > > type conflict > > arch/ia64/xen/xen_pv_ops.c:340: error: xen_iosapic_ops causes a section > > type conflict > > > >This patch simply removes const from data with __initdata. > > > > Yeah, I've seen these sort of messages before, but I don't see why > there's an inherent problem with having const __initdata. > > Sam? The root problem here is that in some cases gcc will stuff this into a section marked CONST and in other cases not. So when we manually specify the section we better not mix const and non-const stuff in the same section. The problem is that it is very gcc dependent. I have with powerpc seen that the same code was not put in CONST with a 32 bit build, but with the 64 bit build it was. The only cure was to remove the const and use initdata. You can try to play with initconst - and it may work. But you need to have pretty good build coverage to be sure. Sam