From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 3/3] ARM: Work around faulty ISAR0 register in some Krait CPUs Date: Mon, 18 Mar 2013 18:19:08 +0000 Message-ID: <20130318181908.GC31193@mudshark.cambridge.arm.com> References: <1363138321-27849-1-git-send-email-sboyd@codeaurora.org> <1363138321-27849-4-git-send-email-sboyd@codeaurora.org> <20130317142854.GC19071@mudshark.cambridge.arm.com> <514748F5.70504@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:36812 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752420Ab3CRST0 (ORCPT ); Mon, 18 Mar 2013 14:19:26 -0400 Content-Disposition: inline In-Reply-To: <514748F5.70504@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Stephen Boyd Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , Stepan Moskovchenko On Mon, Mar 18, 2013 at 05:03:49PM +0000, Stephen Boyd wrote: > On 03/17/13 07:28, Will Deacon wrote: > > On Wed, Mar 13, 2013 at 01:32:01AM +0000, Stephen Boyd wrote: > >> 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 detection code > >> to indicate support in both modes. > >> > >> Cc: Will Deacon > >> Cc: Stepan Moskovchenko > >> Signed-off-by: Stephen Boyd > >> --- > >> arch/arm/kernel/setup.c | 8 ++++++++ > >> 1 file changed, 8 insertions(+) > > After all this, you might as well just pass the relevant HWCAPs for your > > krait entry in proc-v7.S rather than have an exception in the CPU-agnostic > > code. > > Ok. Care to ack the previous patch I sent then? Gah, I can't find the original one. If you resend the series with the changes I suggested in the other mail, I'll add the necessary acks there. Will From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Mon, 18 Mar 2013 18:19:08 +0000 Subject: [PATCH 3/3] ARM: Work around faulty ISAR0 register in some Krait CPUs In-Reply-To: <514748F5.70504@codeaurora.org> References: <1363138321-27849-1-git-send-email-sboyd@codeaurora.org> <1363138321-27849-4-git-send-email-sboyd@codeaurora.org> <20130317142854.GC19071@mudshark.cambridge.arm.com> <514748F5.70504@codeaurora.org> Message-ID: <20130318181908.GC31193@mudshark.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Mar 18, 2013 at 05:03:49PM +0000, Stephen Boyd wrote: > On 03/17/13 07:28, Will Deacon wrote: > > On Wed, Mar 13, 2013 at 01:32:01AM +0000, Stephen Boyd wrote: > >> 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 detection code > >> to indicate support in both modes. > >> > >> Cc: Will Deacon > >> Cc: Stepan Moskovchenko > >> Signed-off-by: Stephen Boyd > >> --- > >> arch/arm/kernel/setup.c | 8 ++++++++ > >> 1 file changed, 8 insertions(+) > > After all this, you might as well just pass the relevant HWCAPs for your > > krait entry in proc-v7.S rather than have an exception in the CPU-agnostic > > code. > > Ok. Care to ack the previous patch I sent then? Gah, I can't find the original one. If you resend the series with the changes I suggested in the other mail, I'll add the necessary acks there. Will