From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D77E9C47080 for ; Wed, 9 Mar 2022 16:32:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236835AbiCIQdA (ORCPT ); Wed, 9 Mar 2022 11:33:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235490AbiCIQXU (ORCPT ); Wed, 9 Mar 2022 11:23:20 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A7F0C3DA74 for ; Wed, 9 Mar 2022 08:21:45 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6D154168F; Wed, 9 Mar 2022 08:21:45 -0800 (PST) Received: from [10.1.29.144] (e121487-lin.cambridge.arm.com [10.1.29.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 573453F7F5; Wed, 9 Mar 2022 08:21:42 -0800 (PST) Subject: Re: [PATCH 2/2] ARM: remove support for NOMMU ARMv4/v5 To: Arnd Bergmann , Robin Murphy Cc: Russell King , Linus Walleij , Arnd Bergmann , kernel test robot , Thomas Gleixner , Marc Zyngier , Ard Biesheuvel , Andrew Morton , Mark Rutland , Linux ARM , Linux Kernel Mailing List , "Russell King (Oracle)" , Anshuman Khandual References: <20220309144138.360482-1-arnd@kernel.org> <20220309144138.360482-2-arnd@kernel.org> <27250b4e-cf04-0dab-d658-bb472face5ea@arm.com> From: Vladimir Murzin Message-ID: <08232117-7444-55d8-e13c-b49828c8f3e9@arm.com> Date: Wed, 9 Mar 2022 16:21:39 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/9/22 4:17 PM, Arnd Bergmann wrote: > On Wed, Mar 9, 2022 at 4:48 PM Robin Murphy wrote: >> >> On 2022-03-09 14:40, Arnd Bergmann wrote: >>> From: Arnd Bergmann >>> >>> It is possible to build MMU-less kernels for Cortex-M base >>> microcrontrollers as well as a couple of older platforms that >>> have not been converted to CONFIG_ARCH_MULTIPLATFORM, >>> specifically ep93xx, footbridge, dove, sa1100 and s3c24xx. >>> >>> It seems unlikely that anybody has tested those configurations >>> in recent years, as even building them is frequently broken. >>> A patch I submitted caused another build time regression >>> in this configuration. I sent a patch for that, but it seems >>> better to also remove the option entirely, leaving ARMv7-M >>> as the only supported Arm NOMMU target for simplicity. >> >> In that case, it would probably make sense to garbage-collect all the >> configs, setup code and other stuff relating to older MMU-less CPU cores >> like ARM1156, ARM940, etc. at the same time. > > Right, good idea. These are only selected by CONFIG_ARCH_INTEGRATOR, > but that in turn doesn't build for CONFIG_MMU=n because it depends on > ARCH_MULTIPLATFORM. I'll send a patch for these. > > I also went back and forth between removing the #ifdefs in > arch/arm/mm/proc-*.S for this patch, though I did not do that in the end. > We may still want them at least for proc-v7.S because that is a small > chance that someone will want to support Cortex-R. > I'd appreciate if you keep them since I run Cortex-R52... Cheers Vladimir > Arnd >