Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755226AbaAVLVf (ORCPT ); Wed, 22 Jan 2014 06:21:35 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:51601 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753419AbaAVLVc (ORCPT ); Wed, 22 Jan 2014 06:21:32 -0500 Date: Wed, 22 Jan 2014 11:20:55 +0000 From: Will Deacon To: Leif Lindholm Cc: "linux-kernel@vger.kernel.org" , "grant.likely@secretlab.ca" , "linux-efi@vger.kernel.org" , "linux@arm.linux.org.uk" , "patches@linaro.org" , "roy.franz@linaro.org" , "matt.fleming@intel.com" , "msalter@redhat.com" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v4 2/5] arm: add new asm macro update_sctlr Message-ID: <20140122112055.GF1621@mudshark.cambridge.arm.com> References: <1389445524-30623-1-git-send-email-leif.lindholm@linaro.org> <1389445524-30623-3-git-send-email-leif.lindholm@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389445524-30623-3-git-send-email-leif.lindholm@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 11, 2014 at 01:05:21PM +0000, Leif Lindholm wrote: > A new macro for setting/clearing bits in the SCTLR. > > Signed-off-by: Leif Lindholm > Suggested-by: Will Deacon > --- > arch/arm/include/asm/assembler.h | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h > index 5c22851..aba6458 100644 > --- a/arch/arm/include/asm/assembler.h > +++ b/arch/arm/include/asm/assembler.h > @@ -383,4 +383,17 @@ THUMB( orr \reg , \reg , #PSR_T_BIT ) > #endif > .endm > > +#ifdef CONFIG_CPU_CP15 > +/* Macro for setting/clearing bits in sctlr */ > + .macro update_sctlr, set:req, clear:req, tmp:req, tmp2:req > + mrc p15, 0, \tmp, c1, c0, 0 > + ldr \tmp2, =\set > + orr \tmp, \tmp, \tmp2 > + ldr \tmp2, =\clear > + mvn \tmp2, \tmp2 > + and \tmp, \tmp, \tmp2 > + mcr p15, 0, \tmp, c1, c0, 0 I think this would be cleaner if you force the caller to put set and clear into registers beforehand, rather than have to do the literal load every time. Also, I don't think set and clear should be required (and then you can lose tmp2 as well). Will -- 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/