Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764154AbZFPUUf (ORCPT ); Tue, 16 Jun 2009 16:20:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763021AbZFPURB (ORCPT ); Tue, 16 Jun 2009 16:17:01 -0400 Received: from ru.mvista.com ([213.79.90.228]:2501 "EHLO buildserver.ru.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1763006AbZFPURA (ORCPT ); Tue, 16 Jun 2009 16:17:00 -0400 Date: Wed, 17 Jun 2009 00:16:30 +0400 From: Anton Vorontsov To: Ingo Molnar Cc: Steven Rostedt , Segher Boessenkool , Sam Ravnborg , Benjamin Herrenschmidt , linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH RFC 1/2] Makefile: Never use -fno-omit-frame-pointer Message-ID: <20090616201630.GA4971@oksana.dev.rtsoft.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1536 Lines: 49 According to Segher Boessenkool and GCC manual, -fomit-frame-pointer is only the default when optimising on archs/ABIs where it doesn't hinder debugging and -pg. So, we do not get it by default on x86, not at any optimisation level. On the other hand, *using* -fno-omit-frame-pointer causes gcc to produce buggy code on PowerPC targets. If Segher and GCC manual are right, this patch should be a no-op for all arches except PowerPC, where the patch fixes gcc issues. Signed-off-by: Anton Vorontsov --- See this thread for more discussion: http://osdir.com/ml/linux-kernel/2009-05/msg01754.html p.s. Obviously, I didn't test this patch on anything else but PPC32. ;-) Segher, do you know if all GCC versions that we support for building Linux are behaving the way that GCC manual describe? Thanks, Makefile | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/Makefile b/Makefile index ea63667..70ad1ff 100644 --- a/Makefile +++ b/Makefile @@ -535,7 +535,7 @@ KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector) endif ifdef CONFIG_FRAME_POINTER -KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls +KBUILD_CFLAGS += -fno-optimize-sibling-calls else KBUILD_CFLAGS += -fomit-frame-pointer endif -- 1.6.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/