From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751186AbdEBM2F (ORCPT ); Tue, 2 May 2017 08:28:05 -0400 Received: from foss.arm.com ([217.140.101.70]:43796 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750886AbdEBM2E (ORCPT ); Tue, 2 May 2017 08:28:04 -0400 Subject: Re: [PATCH] Remove ARM errata Workarounds 458693 and 460075 References: <1492301166-10292-1-git-send-email-nisalmenuka23@gmail.com> <20170416080446.GI17774@n2100.armlinux.org.uk> <20170418155725.GG27592@e104818-lin.cambridge.arm.com> To: Catalin Marinas , Russell King - ARM Linux Cc: vladimir.murzin@arm.com, linux-kernel@vger.kernel.org, dianders@chromium.org, kever.yang@rock-chips.com, linux-arm-kernel@lists.infradead.org, armlinux@m.disordat.com, Nisal Menuka From: Robin Murphy Message-ID: Date: Tue, 2 May 2017 13:27:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170418155725.GG27592@e104818-lin.cambridge.arm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/04/17 16:57, Catalin Marinas wrote: > On Sun, Apr 16, 2017 at 09:04:46AM +0100, Russell King - ARM Linux wrote: >> On Sat, Apr 15, 2017 at 07:06:06PM -0500, Nisal Menuka wrote: >>> According to ARM, these errata exist only in a version of Cortex-A8 >>> (r2p0) which was never built. Therefore, I believe there are no platforms >>> where this workaround should be enabled. >>> link :http://infocenter.arm.com/help/index.jsp?topic= >>> /com.arm.doc.faqs/ka15634.html >> >> These were submitted by ARM Ltd back in 2009 - if the silicon was never >> built, there would've been no reason to submit them. Maybe Catalin can >> shed some light on this, being the commit author who introduced these? > > We normally try not to submit errata workarounds for revisions that are > not going to be built/deployed. It's possible that at the time there > were plans for r2p0 to be licensed and built (not just FPGA) but I don't > really remember the details. The A8 errata document indeed states that > r1p0 and r2p0 are obsolete but this can mean many things (like not > available to license). > > I'll try to see if any of the A8 past product managers know anything > about this. In the meantime, I would leave them in (no run-time > overhead). FWIW, I just fired up a RealView PB-A8 board to check, and that reports r1p1. True, it's not strictly a real silicon implementation (I think it's one of the structured ASIC test chips), but since it was, as far as I'm aware, a commercially-available development system, it's not impossible that someone may still own and use one of these beasts. Robin.