From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753610AbaIYPLK (ORCPT ); Thu, 25 Sep 2014 11:11:10 -0400 Received: from mout.kundenserver.de ([212.227.17.10]:51196 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753013AbaIYPLF (ORCPT ); Thu, 25 Sep 2014 11:11:05 -0400 From: Arnd Bergmann To: Will Deacon Cc: "linux-arch@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "benh@kernel.crashing.org" , "chris@zankel.net" , "cmetcalf@tilera.com" , "davem@davemloft.net" , "deller@gmx.de" , "dhowells@redhat.com" , "geert@linux-m68k.org" , "heiko.carstens@de.ibm.com" , "hpa@zytor.com" , "jcmvbkbc@gmail.com" , "jesper.nilsson@axis.com" , "mingo@redhat.com" , "monstr@monstr.eu" , "paulmck@linux.vnet.ibm.com" , "rdunlap@infradead.org" , "sam@ravnborg.org" , "schwidefsky@de.ibm.com" , "starvik@axis.com" , "takata@linux-m32r.org" , "tglx@linutronix.de" , "tony.luck@intel.com" , "daniel.thompson@linaro.org" , "broonie@linaro.org" , "linux@arm.linux.org.uk" , "thierry.reding@gmail.com" Subject: Re: [PATCH v3 00/17] Cross-architecture definitions of relaxed MMIO accessors Date: Thu, 25 Sep 2014 17:07:47 +0200 Message-ID: <3361270.4SkjDs5lox@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20140925145538.GN20043@arm.com> References: <1411579056-16966-1-git-send-email-will.deacon@arm.com> <2811016.mhqlsl6pTS@wuerfel> <20140925145538.GN20043@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V02:K0:QQ3+Fv4Uaa0r1xyBdlmGBX38ZsbCJZcUb6Lxc4/NveD 6KWXLK8O5U/FxwAKUwjOS7G8B+T7mEP7OutOEi6KODSaml9KBN DeeVc+bGFx1PwVHlx5AEQ9EakNyqslOb2e6lfyO21fDXaAtTDw wKsmU1JPNMol3BK5WibuGVZstFIdWNzKz6bo5xZrcMM20Mpp0k FcURBQd2+PKflQRoM68v2igDdNkqzNnQ0tcUQWIETXOaeR4QQL +Vp19bgqLVs1uv2XNMAYzJdQr4BdMEt10I0TfuKgg7WwNhyr5Q a1yFNv2YgVgxjCQENdKsO2r6VWF+UcC2T00+qSLzhOYAzucJ59 Osf8ZXMowhoEA5Hgc3MI= X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 25 September 2014 15:55:38 Will Deacon wrote: > On Thu, Sep 25, 2014 at 02:15:10PM +0100, Arnd Bergmann wrote: > > On Wednesday 24 September 2014 18:17:19 Will Deacon wrote: > > > This is version three of the series I've originally posted here: > > > > > > v1: https://lkml.org/lkml/2014/4/17/269 > > > v2: https://lkml.org/lkml/2014/5/22/468 > > > > > > This is basically just a rebase on top of 3.17-rc6, minus the alpha patch > > > (which was merged into mainline). > > > > > > I looked at reworking the non-relaxed accessors to imply mmiowb, but it > > > quickly got messy as some architectures (e.g. mips) deliberately keep > > > mmiowb and readX/writeX separate whilst others (e.g. powerpc) don't trust > > > drivers to get mmiowb correct, so add barriers to both. Given that > > > arm/arm64/x86 don't care about mmiowb, I've left that as an exercise for > > > an architecture that does care. > > > > > > In order to get this lot merged, we probably want to merge the asm-generic > > > patch (1/17) first, so Acks would be much appreciated on the architecture > > > bits. > > > > > > As before, I've included the original cover letter below, as that describes > > > what I'm trying to do in more detail. > > > > > > > I've now applied the parts of your series that are required to have > > every architecture provide all the 'relaxed' accessors to the > > asm-generic tree, on top of Thierry's series. > > Brill, thanks Arnd! I'll repost what's left during the next cycle, however > I think you also need to pick the microblaze patch as it includes > before defining its relaxed accessors, so I think > you'll get a redefinition warning from the preprocessor. Good point, I'll add that on top then. > > I had to change your first patch significantly because all the context > > changed in his patches. See below for the new version. Thierry, can > > you also confirm that this matches up with the intention of your > > series? Since that now adds a separate #ifdef for each symbol, I > > ended up putting the #ifdef for the relaxed version inside of the > > #ifdef for the non-relaxed version, but it could alternatively > > be defined outside of it as well. > > I think both work, as I can't find any architectures that define the > relaxed variants but not the non-relaxed versions. Actually I just made up my mind about that: Architectures are actually supposed to provide the non-relaxed versions themselves using inline assembly, but they don't need to provide the relaxed version. The current version doesn't let you do that, so I'll keel the #ifdef sections separate. This also means that I won't apply your patch 17: we will keep needing the #ifdef to support all three relevant combinations: a) architectures that provide neither and want to get the defaults from asm-generic b) architectures that provide the non-relaxed versions and want tog to get just the relaxed version from asm-generic c) architectures that provide both Arnd