From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754368Ab3CRSev (ORCPT ); Mon, 18 Mar 2013 14:34:51 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:37000 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753630Ab3CRSet (ORCPT ); Mon, 18 Mar 2013 14:34:49 -0400 Date: Mon, 18 Mar 2013 18:34:36 +0000 From: Will Deacon To: Stephen Boyd Cc: "linux-arm-kernel@lists.infradead.org" , Stepan Moskovchenko , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" Subject: Re: [PATCHv2 3/3] ARM: Work around faulty ISAR0 register in some Krait CPUs Message-ID: <20130318183435.GD31193@mudshark.cambridge.arm.com> References: <1363631337-13816-1-git-send-email-sboyd@codeaurora.org> <1363631337-13816-4-git-send-email-sboyd@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1363631337-13816-4-git-send-email-sboyd@codeaurora.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 Mon, Mar 18, 2013 at 06:28:57PM +0000, Stephen Boyd wrote: > From: Stepan Moskovchenko > > Some early versions of the Krait CPU design incorrectly indicate > that they only support the UDIV and SDIV instructions in Thumb > mode when they actually support them in ARM and Thumb mode. It > seems that these CPUs follow the DDI0406B ARM ARM which has two > possible values for the divide instructions field, instead of the > DDI0406C document which has three possible values. > > Work around this problem by checking the MIDR against Krait CPUs > with this faulty ISAR0 register and force the hwcaps to indicate > support in both modes. > > Cc: Will Deacon > Signed-off-by: Stepan Moskovchenko > [sboyd: Rewrote commit text to reflect real reasoning now that > we autodetect udiv/sdiv] > Signed-off-by: Stephen Boyd > --- > arch/arm/mm/proc-v7.S | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) Acked-by: Will Deacon Will