From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp1 ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms11 with LMTPS id 2pZbHqxh+F/cRwAA0tVLHw (envelope-from ) for ; Fri, 08 Jan 2021 13:44:12 +0000 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp1 with LMTPS id SGmPGaxh+F/0UwAAbx9fmQ (envelope-from ) for ; Fri, 08 Jan 2021 13:44:12 +0000 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id 14A87940416 for ; Fri, 8 Jan 2021 13:44:12 +0000 (UTC) Received: from localhost ([::1]:47176 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kxs3n-0007pn-0x for larch@yhetil.org; Fri, 08 Jan 2021 08:44:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:45360) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kxs3d-0007oL-E0 for guix-devel@gnu.org; Fri, 08 Jan 2021 08:44:01 -0500 Received: from dd26836.kasserver.com ([85.13.145.193]:45784) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kxs3Z-0004Nb-Qi; Fri, 08 Jan 2021 08:44:00 -0500 Received: from localhost (80-110-127-104.cgn.dynamic.surfer.at [80.110.127.104]) by dd26836.kasserver.com (Postfix) with ESMTPSA id 62D7333652C1; Fri, 8 Jan 2021 14:43:52 +0100 (CET) Date: Fri, 8 Jan 2021 14:43:47 +0100 From: Danny Milosavljevic To: Jan Nieuwenhuizen Subject: Re: [bootstrappable] Re: wip-full-source-bootstrap: from a 357-byte `hex0' to 'hello' Message-ID: <20210108144347.12d82f90@scratchpost.org> In-Reply-To: <87ble0ueq7.fsf@gnu.org> References: <87im8cvdpa.fsf@gnu.org> <36b3777d90af6fa2e1c1778ba183111e@codethink.co.uk> <87lfd5rpr8.fsf@gnu.org> <20210107211058.40e0813a@scratchpost.org> <20210107212324.36bfd236@scratchpost.org> <20210107235208.04835b95@scratchpost.org> <87ble0ueq7.fsf@gnu.org> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/mA6aJeFJFIwOm81/X_.8KYg"; protocol="application/pgp-signature"; micalg=pgp-sha512 Received-SPF: none client-ip=85.13.145.193; envelope-from=dannym@scratchpost.org; helo=dd26836.kasserver.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: guix-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: guix-devel@gnu.org, tinycc-devel@nongnu.org, Michael Matz , Paul Sherwood , bootstrappable@freelists.org Errors-To: guix-devel-bounces+larch=yhetil.org@gnu.org Sender: "Guix-devel" X-Migadu-Flow: FLOW_IN X-Migadu-Spam-Score: -2.45 Authentication-Results: aspmx1.migadu.com; dkim=none; dmarc=none; spf=pass (aspmx1.migadu.com: domain of guix-devel-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-devel-bounces@gnu.org X-Migadu-Queue-Id: 14A87940416 X-Spam-Score: -2.45 X-Migadu-Scanner: scn0.migadu.com X-TUID: PunhMiAYYqzD --Sig_/mA6aJeFJFIwOm81/X_.8KYg Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi Janneke, On Fri, 08 Jan 2021 07:25:52 +0100 Jan Nieuwenhuizen wrote: > > Alignment could be disabled on the CPU > > > > https://developer.arm.com/documentation/ddi0464/f/system-control/regi= ster-descriptions/system-control-register > > > > but I don't think EABI wants that. =20 >=20 > Hmm, what does this mean? We are not really using EABI, or are we? VFP is a floating point unit on ARM CPUs. It has been designed to either require aligned members and be fast, or not, depending on a CPU flag that for example the kernel can set. See also https://www.keil.com/support/man/docs/armcc/armcc_chr1359124231926= .htm for much more detail. ARM is a famously mix-and-match CPU, so the client can choose whatever they want. If you choose aligned-only, you will get a bus error on misaligned access. A single program really shouldn't be choosing--it's more the entire platform doing the choosing. EABI has standardized on particular settings, among which is required align= ment. > So alignment should be fixed, but that's more work and you propose a > workaround, right? =20 No, I wanted to find out what's going on first. Now that grischka commented and I looked up the malloc docs, I suggest to fix mes libc's malloc to align what it gives back. That's all--that should fix everything. We should provide maxalign_t to make it known to the user what the malloc alignment we are using is. --Sig_/mA6aJeFJFIwOm81/X_.8KYg Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEds7GsXJ0tGXALbPZ5xo1VCwwuqUFAl/4YZMACgkQ5xo1VCww uqV0Awf/VnUUk3JnRokqXxHpjAsYmorsRTUhhTbdnK2wS6Li3ih3I8nyJA4wGSYc P/7pj2ji46kUfutOgFOGyPq73EpcSzrU+RDDa4muFk1t9pkDx7XB4+M3V42yMy3U FDyF2NoUasSPskreOxCbMQGHb0h+0nM2QPuvBz4qHvBH+IcMaeq1pv0QscGHGix/ 3F3ZdcEAerQtZ04AANF+slYUMd+qm541GkrYDEN2sdDGPtXt91sPy6n5FIfjFwxz Nobx5eEffitnQOrBX0eeLP9Iao3G1g7P1I+A8UwAYevoYLQDJfSSN+k8eeLP7eTV QTd9IqWpKuoSaxU/57TTin3kbdCz+A== =T/cm -----END PGP SIGNATURE----- --Sig_/mA6aJeFJFIwOm81/X_.8KYg--