From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from xes-mad.com (xes-mad.com [216.165.139.214]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id EB3A7DDEF0 for ; Sat, 25 Oct 2008 10:51:35 +1100 (EST) Subject: Re: [PATCH] powerpc: enforce a non-spe kernel build even on broken compilers From: Nate Case To: Sebastian Andrzej Siewior In-Reply-To: <1224252131.7879.117.camel@localhost.localdomain> References: <20080901142302.GA13754@www.tglx.de> <76A823BD-A9B8-4FB4-B09B-F818687193CA@kernel.crashing.org> <20081014224946.GA2503@www.tglx.de> <20081015085904.GA28369@Chamillionaire.breakpoint.cc> <6115D7FB-7500-4F67-B02B-B64B92B33D1A@kernel.crashing.org> <20081015144359.GA30649@Chamillionaire.breakpoint.cc> <1224252131.7879.117.camel@localhost.localdomain> Content-Type: text/plain Date: Fri, 24 Oct 2008 18:51:17 -0500 Message-Id: <1224892277.30047.64.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, ths@linutronix.de List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2008-10-17 at 09:02 -0500, Nate Case wrote: > > With this patch it compiles and boots fine. > > The option -mabi=no-spe is not required. > > Please don't accept this patch yet. My past testing showed that > "-mabi=no-spe" was required for my toolchain. I'll go back and double > check though. OK, I went back and re-tested. Kernel: 2.6.27 CPU: MPC8572 Toolchain: Cross-compiler built using crosstool-ng gcc 4.3.1, default target CFLAGS include '-mabi=spe -mspe' binutils 2.18.90 snapshot (built with --enable-spe=yes) Kbuild flags Result ------------ ------ -mno-spe (*) FAILED -mno-spe -mabi=no-spe FAILED -mno-spe -mspe=no OK -mspe=no OK (*) 2.6.27 default In the failure case, the kernel would repeatedly dump out "SPE used in kernel (task=xxxxxxxx, pc=xxxxxxxx)". I think I was fooled before because I added _both_ "-mspe=no" and "-mabi=no-spe" to my KBUILD_CFLAGS and saw the problem go away. Since I trusted the documentation that -mspe=no and -mno-spe were the same, I assumed that -mabi=no-spe was the key. So, I've changed my mind. I now agree with Sebastian that "-mabi=no-spe" is not required. "-mno-spe -mspe=no" is probably the safe way to go. -- Nate Case