From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753470Ab0BWSjm (ORCPT ); Tue, 23 Feb 2010 13:39:42 -0500 Received: from mail-gy0-f174.google.com ([209.85.160.174]:40229 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753070Ab0BWSjl (ORCPT ); Tue, 23 Feb 2010 13:39:41 -0500 X-Greylist: delayed 88473 seconds by postgrey-1.27 at vger.kernel.org; Tue, 23 Feb 2010 13:39:40 EST DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=gHaARX/ZDolbfakLNJCTE46NC3mxJPZRUH4xIGxwx4CHgOTo4hUvfx0DE7DdQbBiK7 lJBzTSkodV83Nlmt+Bab0n0RCX7fhb2ZrLLCXeVjItBpt4st5aLaWV7a3Y3dhuDdVXio yrG4fer5gKNmNckYvD/ayBEdMoN4DUZK8qu5U= Date: Wed, 24 Feb 2010 00:11:04 +0530 From: Rabin Vincent To: Steven Rostedt Cc: Frederic Weisbecker , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ingo Molnar , Abhishek Sagar , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH 04/10] ARM: ftrace: allow building without frame pointers Message-ID: <20100223184104.GA6325@debian> References: <1266090518-31120-1-git-send-email-rabin@rab.in> <1266090518-31120-5-git-send-email-rabin@rab.in> <20100222190516.GJ5055@nowhere> <1266931113.19540.5.camel@frodo> <20100223171112.GC5357@nowhere> <20100223175807.GB5836@debian> <1266948185.24271.6079.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1266948185.24271.6079.camel@gandalf.stny.rr.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 23, 2010 at 01:03:05PM -0500, Steven Rostedt wrote: > On Tue, 2010-02-23 at 23:28 +0530, Rabin Vincent wrote: > > The easiest option to have a more obvious message than a linker error > > would be to add something like this in entry-common.S: > > > > #if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)) \ > > && !defined(OLD_MCOUNT) > > #warning Ftrace on GCC < 4.4 requires frame pointers > > #endif > > > > Messages like this are also present in other places in ARM (for example > > arch/arm/kernel/unwind.c), so this wouldn't be this first. > > > > Note that the above message would help in all cases except the one where > > someone builds the kernel with !fp and GCC 4.4+, and then builds a > > module with an older GCC. That would still be only a linker error. > > I was going to recommend the #if above. But shouldn't it be a #error > instead of a #warning? Yes, I'll make it a #error. (I had it at #warning in case some one had a custom compiler that had the new mcount patch backported, and chose to ignore the warning. But it's probably better to leave it at #error and see if someone actually complains about it, rather than have someone miss the message with it as a #warning.) Rabin