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 7571DC433FE for ; Wed, 9 Mar 2022 16:23:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232516AbiCIQYD (ORCPT ); Wed, 9 Mar 2022 11:24:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237979AbiCIQVM (ORCPT ); Wed, 9 Mar 2022 11:21:12 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 805C3E10 for ; Wed, 9 Mar 2022 08:17:41 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 516DEB82221 for ; Wed, 9 Mar 2022 16:17:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E277C340F7 for ; Wed, 9 Mar 2022 16:17:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646842659; bh=wcHvu5yCe5RwLv3/dGOPzc0JNrj+q5a53qp5+a2m21I=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=P4s8nVLyAwUaVuySt4MjswdVCrghJHdXHJWl11pfoO8oNuQowU/27mk//j2znrI15 UcX2Je00Fe/yWxKR36XA4BnsbGm5126STh4cbCeThPI6pcewwFDovbVCUQxSuZFSeE a8RtKl26PRJwVSKhnFXti3dFCNR+KMcLAr5MlcdNZeRazqr2mz5wlHtfhTqYwG0hhV 0mz9aI8sjFa4CvY17I2byucqi+P/AHz971xcGi9GiGmkdhw4FJs/kdiweashl0IunM BLAhn2BGxtOPYxNQCuoeoSxbDvtJWx1R7q0Qb0dLEa936LWi4IyCFjUskUwZP2T4IT dms7AHozZ9kDg== Received: by mail-wr1-f52.google.com with SMTP id u1so3825250wrg.11 for ; Wed, 09 Mar 2022 08:17:39 -0800 (PST) X-Gm-Message-State: AOAM531IqslL4RBccobkVyYvMAhj8tSsL1QZUuG5oRDPPza9BPa7WA8u NvDhdrBAk5rWITHQzlo45uBCxuKeGEhcI2tEF2Q= X-Google-Smtp-Source: ABdhPJxGoyWxihc52YXH4rfuLZkMFEs/nxgBgrYnRqvXSt4UGzbMzOAuUKsccPsfh8OGvNhkES6t/rUrJkFkhtYrkP0= X-Received: by 2002:a5d:6810:0:b0:203:7cbb:20be with SMTP id w16-20020a5d6810000000b002037cbb20bemr283536wru.219.1646842657281; Wed, 09 Mar 2022 08:17:37 -0800 (PST) MIME-Version: 1.0 References: <20220309144138.360482-1-arnd@kernel.org> <20220309144138.360482-2-arnd@kernel.org> <27250b4e-cf04-0dab-d658-bb472face5ea@arm.com> In-Reply-To: <27250b4e-cf04-0dab-d658-bb472face5ea@arm.com> From: Arnd Bergmann Date: Wed, 9 Mar 2022 17:17:21 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/2] ARM: remove support for NOMMU ARMv4/v5 To: Robin Murphy Cc: Russell King , Linus Walleij , Arnd Bergmann , kernel test robot , Thomas Gleixner , Marc Zyngier , Ard Biesheuvel , Andrew Morton , Mark Rutland , Vladimir Murzin , Linux ARM , Linux Kernel Mailing List , "Russell King (Oracle)" , Anshuman Khandual Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Arnd