From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH v4 2/5] arm: add new asm macro update_sctlr Date: Wed, 22 Jan 2014 11:20:55 +0000 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 Return-path: Content-Disposition: inline In-Reply-To: <1389445524-30623-3-git-send-email-leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Leif Lindholm Cc: "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org" , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org" , "patches-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "roy.franz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org" , "msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: linux-efi@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