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 EC9C1DDF5E for ; Wed, 15 Oct 2008 06:25:36 +1100 (EST) Subject: Re: [PATCH] powerpc: enforce a non-spe kernel build even on broken compilers From: Nate Case To: Sebastian Siewior In-Reply-To: <20080901142302.GA13754@www.tglx.de> References: <20080901142302.GA13754@www.tglx.de> Content-Type: text/plain Date: Tue, 14 Oct 2008 14:25:20 -0500 Message-Id: <1224012320.7879.79.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 Mon, 2008-09-01 at 16:23 +0200, Sebastian Siewior wrote: > those two are requried on my fresh gcc 4.3.1 > > Signed-off-by: Thiemo Seufer > Signed-off-by: Sebastian Siewior > --- > Not sure if this is intendent or a gcc bug but with -mno-spe > the spe opcodes were not used floating point anymore but > for 64bit save/restore for instance. I wouldn't say this is due to a broken compiler. As I understand it, -mabi=no-spe and -mspe=no serve two different purposes. One is for disabling the SPE instructions and the other controls the ABI (which would make those 64-bit save/restores I'm guessing). I don't know why you'd ever want to use the SPE ABI without -mspe=yes, but gcc does provide that flexibility. -mno-spe: Deprecated way to say "no SPE instructions" -mspe=no: New way to do -mno-spe -mabi=no-spe: Disable SPE ABI Some compilers may enable "-mabi=spe" and/or "-mspe=yes" by default, so explicitly disabling both is necessary. I recently built a SPE toolchain which enabled both by default, so I ran into the "SPE used in kernel" problem when the kernel only passed "-mno-spe". - Nate Case