Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752746Ab3FZRMX (ORCPT ); Wed, 26 Jun 2013 13:12:23 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:60551 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752299Ab3FZRMW (ORCPT ); Wed, 26 Jun 2013 13:12:22 -0400 Date: Wed, 26 Jun 2013 18:11:38 +0100 From: Will Deacon To: Christopher Covington Cc: "linux-arm-kernel@lists.infradead.org" , Russell King , Catalin Marinas , Nicolas Pitre , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] ARM: Add support for LPAE style CONTEXTIDR Message-ID: <20130626171138.GF10333@mudshark.cambridge.arm.com> References: <1372080405-13365-1-git-send-email-cov@codeaurora.org> <20130624140424.GA24861@mudshark.cambridge.arm.com> <51C85A0D.3070400@codeaurora.org> <20130624145303.GA25582@mudshark.cambridge.arm.com> <51C8627A.5000106@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51C8627A.5000106@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 Content-Length: 1285 Lines: 32 On Mon, Jun 24, 2013 at 04:15:06PM +0100, Christopher Covington wrote: > On 06/24/2013 10:53 AM, Will Deacon wrote: > > On Mon, Jun 24, 2013 at 03:39:09PM +0100, Christopher Covington wrote: > >> Hi Will, > >> > >> On 06/24/2013 10:04 AM, Will Deacon wrote: > >> [...] > >> > >>> What's the advantage of this approach, other than you get an extra byte's > >>> worth of PID? > >> > >> In my view, the real advantage is that the the PID is located where people > >> reading ARM Architecture Reference Manual are told they can find it. > > > > Perhaps, but I'd usually expect a debugger or trace tools to do something > > with the PID, and they likely expect it to be shifted, so you can't really > > win. > > But reading and implementing the architecture *is* winning! LOL. I'll file a > ticket with the architecture folks and see what they think. ...aaand that came full circle :) I think the conclusion is that Linux PID != CONTEXTIDR.PROCID, so there's no architectural issue here. I'm just trying to keep it easy for the tools. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/