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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E12BC433E0 for ; Fri, 12 Feb 2021 12:36:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE1FA64E30 for ; Fri, 12 Feb 2021 12:36:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230404AbhBLMgy (ORCPT ); Fri, 12 Feb 2021 07:36:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:54016 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229907AbhBLMgu (ORCPT ); Fri, 12 Feb 2021 07:36:50 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0A4B564DEE; Fri, 12 Feb 2021 12:36:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1613133369; bh=cnTIOUrwbSss0NsP381REUNNVtv0SaySoeMM4ym6xLs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RdlEud5Vcwv7Bbex5r6Y2fe3o5GEdrpUXdmwC0fYOpCiL0irjf7O+vggKqq0yhlSZ Dgsz/WmSW5yJs2O+61tMAy9BcqrM+RH3X1cNRDsmN1SA1MbaATctkDSdVMV1xxdVGG A/+ZR/RWTWI8VZdTA8B7rzmUekXxmkr/QiRN3IxmXk3p+nZxCvzaYYV+US91+Y8gqi 0tTIkwnob0V+vuLPht5lZD4a+ikD83oj4+4he7+4Dr5aTLDheqSRdd6g5LyUtJUhw1 m0hBkXbZMzeNZFdoVVH7Jy2km0smiY+44p8m8QYJfN5IbCTHhNhQ/UTIr8AfBvmRD5 JqfoLrfPW/UBA== Date: Fri, 12 Feb 2021 12:35:15 +0000 From: Mark Brown To: Steven Price Cc: sonicadvance1@gmail.com, amanieu@gmail.com, Catalin Marinas , Will Deacon , Mark Rutland , Oleg Nesterov , Al Viro , Dave Martin , Amit Daniel Kachhap , Marc Zyngier , David Brazdil , Jean-Philippe Brucker , Andrew Morton , Anshuman Khandual , Gavin Shan , Mike Rapoport , Vincenzo Frascino , Kristina Martsenko , Kees Cook , Sami Tolvanen , Frederic Weisbecker , Kevin Hao , Jason Yan , Andrey Ignatov , Peter Collingbourne , Julien Grall , Tian Tao , Qais Yousef , Jens Axboe , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND RFC PATCH v2] arm64: Exposes support for 32-bit syscalls Message-ID: <20210212123515.GC6057@sirena.org.uk> References: <20210211202208.31555-1-Sonicadvance1@gmail.com> <58b03e17-3729-99ea-8691-0d735a53b9bc@arm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Md/poaVZ8hnGTzuv" Content-Disposition: inline In-Reply-To: <58b03e17-3729-99ea-8691-0d735a53b9bc@arm.com> X-Cookie: One size fits all. User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Md/poaVZ8hnGTzuv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Feb 12, 2021 at 11:30:41AM +0000, Steven Price wrote: > On 11/02/2021 20:21, sonicadvance1@gmail.com wrote: > > Why do we need compatibility layers? > > There are ARMv8 CPUs that only support AArch64 but still need to run > > AArch32 applications. > > Cortex-A34/R82 and other cores are prime examples of this. > > Additionally if a user is needing to run legacy 32-bit x86 software, it > > needs the same compatibility layer. > Unless I'm much mistaken QEMU's user mode already does this - admittedly I > don't tend to run "legacy 32-bit x86 software". Yes, this has been deployed on Debian for a long time - you can install any combination of Debian architectures on a single system and it will use qemu to run binaries that can't be supported natively by the hardware. --Md/poaVZ8hnGTzuv Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmAmdgIACgkQJNaLcl1U h9Ar6Qf7Be9ErKtx5lm+ZTtLIlBvwbYKuCANK8wuDnCzLybGOxE/0n+OHlsJsPoh +HgRSrSab9IvlOcPXxJZ7tWr81ZW8JHdP+gVAKV2ogYn18IWni9jiFw1ti1qru6m y8ow6AFHYS2BryKDPchKalvl3iKVcYGkWvtZVwvK0+0K6PkWCNOIRKI7vRNbqXKa EvMjgvlb//CumMk6TnW3TajWnK5SCpoUN8aP+s5+SJsAsOwpySsum2lwNDXqc1R1 2xYXdB1pgtWgjA7WtasM1W0xwAJ8ol81BaU6FzFXToOPBxg31dff/9dQHXuSyedk r6DqAhGK+pyhY6mhQJvV5jTzaPad+A== =UG5o -----END PGP SIGNATURE----- --Md/poaVZ8hnGTzuv--