From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 86023DDF53 for ; Thu, 22 Mar 2007 17:10:50 +1100 (EST) Subject: [RFC/PATCH] powerpc: Always use -mno-string & -mno-multiple From: Benjamin Herrenschmidt To: Paul Mackerras Content-Type: text/plain Date: Thu, 22 Mar 2007 17:10:38 +1100 Message-Id: <1174543838.10836.21.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev list , Akinobu Mita List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , powerpc: Always use -mno-string and -mno-multiple The string and multiple load/store instructions are causing more damage than help on a lot of processors where they are microcoded and are generally no good for the kernel to use. Let's make sure we don't emit them on any powerpc variant. Signed-off-by: Benjamin Herrenschmidt --- Is that actually true ? What about 601 ? 4xx ? Do we want to keep generating those for space on embedded processors where they actually work (if they do) ? Index: linux-cell/arch/powerpc/Makefile =================================================================== --- linux-cell.orig/arch/powerpc/Makefile 2007-03-22 17:02:42.000000000 +1100 +++ linux-cell/arch/powerpc/Makefile 2007-03-22 17:05:23.000000000 +1100 @@ -102,9 +102,9 @@ CFLAGS += $(call cc-option,-mno-altivec) # kernel considerably. CFLAGS += $(call cc-option,-funit-at-a-time) -ifndef CONFIG_FSL_BOOKE -CFLAGS += -mstring -endif +# Never use string and multiple load/store instructions as they are +# often slow when they are implemented at all +CFLAGS += -mno-string -mno-multiple ifeq ($(CONFIG_6xx),y) CFLAGS += -mcpu=powerpc