From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759076Ab3B0BhU (ORCPT ); Tue, 26 Feb 2013 20:37:20 -0500 Received: from wolverine01.qualcomm.com ([199.106.114.254]:17219 "EHLO wolverine01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754637Ab3B0BhS (ORCPT ); Tue, 26 Feb 2013 20:37:18 -0500 X-IronPort-AV: E=Sophos;i="4.84,744,1355126400"; d="scan'208";a="26748431" Message-ID: <512D634D.5010600@codeaurora.org> Date: Tue, 26 Feb 2013 17:37:17 -0800 From: Stephen Boyd User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:17.0) Gecko/20130215 Thunderbird/17.0.3 MIME-Version: 1.0 To: Russell King - ARM Linux CC: linux-arm-msm@vger.kernel.org, Steve Muckle , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] ARM: vfp: fix fpsid register subarchitecture field mask width References: <1361520485-30269-1-git-send-email-sboyd@codeaurora.org> <20130225172545.GO17833@n2100.arm.linux.org.uk> <20130225200209.GP17833@n2100.arm.linux.org.uk> In-Reply-To: <20130225200209.GP17833@n2100.arm.linux.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/25/13 12:02, Russell King - ARM Linux wrote: > > This can of worms is getting bigger. We have more problems with our > handling of the different VFP versions, specifically the handling of > the EX=0 DEX=0 case. > > VFP common subarch 3 defines the EX=0, DEX=0 encoding to mean one of > the following conditions have been met: > > 1. an unallocated VFP instruction was encountered. > > In other words, the VFP was the target of the co-processor instruction, > but the instruction is not a known VFP instruction encoding. This > should raise an undefined instruction exception. > > 2. an allocated VFP instruction was encountered, but not handled in > hardware. > > In other words, the instruction is a valid VFP instruction, but the > hardware has opted not to implement this instruction and wants > software to emulate it instead. > > (Note: this can also be raised as EX=0, DEX=1 - implementation > defined!) > [snip] > > So, if EX or DEX is set, _or_ IXE is set, we pass control to VFP_bounce. > This is problematical. > > (a) condition (2) above isn't correctly handled for common subarch v3 - it > is always treated as an undefined instruction, and will result in a > SIGILL being delivered. > [snip] > > Now, (a) is just bad behaviour - as we haven't had any reports of this > yet, I suspect that no one has implemented VFP hardware with this > behaviour yet. I believe we ran into this a while ago and fixed it for our chips. We never sent the patch upstream. Sorry. https://www.codeaurora.org/gitweb/quic/la/?p=kernel/msm.git;a=commitdiff;h=00a13be874f230159a6b7f8cc9d0ff23bc1b7d05 I'm looking into what our bits correspond to. Hopefully get back to you in 20 something hours. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation