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 3196AE7AD48 for ; Tue, 3 Oct 2023 13:38:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236365AbjJCNiV (ORCPT ); Tue, 3 Oct 2023 09:38:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232653AbjJCNiQ (ORCPT ); Tue, 3 Oct 2023 09:38:16 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87F82A9; Tue, 3 Oct 2023 06:38:13 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B35ABC433C7; Tue, 3 Oct 2023 13:38:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696340293; bh=uwtqnUxTMKbAVfD+gZWXN+2nSoPSgsCGQxxJs5nbdeo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hmdjXMqXyZeGSvyuQRufMD+IbooZlHt4Fl+2QKKDFRxTKFWqLtibJL9fD2WNsXRqn PpPdqOp7OhH7MsubfkpS6TMDyTKN/AeMfpIWAAhKiHBW6JEQ3eVUvzKQho+r0c73bq uSoe4cVF/Qi/iaTEhllRcf5K1O5CZiHLBq7R6bewNsL3AMIX0hrDkyw4IamVbeEUVY H7fYoWgMgUl9JjkhObUuvSdL4RBWAerpg148lOtgda7gOTMm7ojp6Djmbc+MxP93EK lDx842uWlD4YM9qLneth2OoHkxGe3TPPF+PSAUpxItWZWQKpSHLSND54oimTw+6Bas PVQHDSsJ52lWQ== Date: Tue, 3 Oct 2023 14:38:02 +0100 From: Mark Brown To: "Edgecombe, Rick P" Cc: "Szabolcs.Nagy@arm.com" , "corbet@lwn.net" , "ardb@kernel.org" , "maz@kernel.org" , "shuah@kernel.org" , "linux-kernel@vger.kernel.org" , "keescook@chromium.org" , "james.morse@arm.com" , "debug@rivosinc.com" , "akpm@linux-foundation.org" , "palmer@dabbelt.com" , "catalin.marinas@arm.com" , "hjl.tools@gmail.com" , "paul.walmsley@sifive.com" , "linux-mm@kvack.org" , "aou@eecs.berkeley.edu" , "oleg@redhat.com" , "arnd@arndb.de" , "ebiederm@xmission.com" , "will@kernel.org" , "suzuki.poulose@arm.com" , "kvmarm@lists.linux.dev" , "linux-doc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-fsdevel@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "linux-arch@vger.kernel.org" , "oliver.upton@linux.dev" , "linux-riscv@lists.infradead.org" Subject: Re: [PATCH v4 03/36] arm64/gcs: Document the ABI for Guarded Control Stacks Message-ID: <3985b0d8-e35e-4cd5-a2bd-6a16d7c7e559@sirena.org.uk> References: <43ec219d-bf20-47b8-a5f8-32bc3b64d487@sirena.org.uk> <38edb5c3-367e-4ab7-8cb7-aa1a5c0e330c@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="VOYoYIe/0D3GI3W0" Content-Disposition: inline In-Reply-To: X-Cookie: Oh Dad! We're ALL Devo! Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --VOYoYIe/0D3GI3W0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Oct 02, 2023 at 09:43:25PM +0000, Edgecombe, Rick P wrote: > If ARM is thinking of doing things differently than x86, you might > think about how you weight those tradeoffs. Like, it might be silly to > worry about clone() support if something else ends up breaking > compatibility majorly. But, it might be worthwhile it you end up going > to the proposed extremes around signal alt stacks, to maximize > compatibility Yeah, I think Catalin's thinking here was that we're quite a way out =66rom actual hardware so it's much more tractable to fix up callers than it is for x86 where the hardware is widely available. > Also then maybe x86 could copy the ARM ABI some day, if it ends up > chasing the tradeoff people prefer. It probably goes without saying > that the closer these features behave from the app developer > perspective, the better. So a different ABI than x86 that also targets > a mix would be a bit unfortunate. (not the end of the world though) If nothing else even if we end up being stricter about things it would be extremely disappointing if we ended up with something where code for arm64 won't run when built for x86. --VOYoYIe/0D3GI3W0 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmUcGToACgkQJNaLcl1U h9DGrwf/e1Q1mca/c+Y8gjB9uTmkbz6UTxEP5Ie+SQ8OHE0DeQjg4wUgWFKyhONR Gja5KPwSLlu7n1otNu8P3ztqCLwd3+sa1yM4Tzhq965l/wqp1cmwh3OcRJwWNO/w TzGqD8fnAAZY6EyfMg6oP8IcWvD1ru5jttF18YdJdekWjBGQyWI+aZaN8ERdT1hG 8G2Jz0DOJCCRuMo4JWQQ7wyKmgXsaCsO0UeTLsniZYatysygBlZPnxwG+kSlwwrP jJwDtljE9WONcZZttwNT0Rn/dFpXj4cO5L0RjHX/HPvHmSwOgdnO4fBD2HSL53xL WSStamx5uiW/Ch8ilcxeRdcT+rL/Jw== =Wyj+ -----END PGP SIGNATURE----- --VOYoYIe/0D3GI3W0--