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 8AE7CC05027 for ; Wed, 8 Feb 2023 18:19:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230335AbjBHSTX (ORCPT ); Wed, 8 Feb 2023 13:19:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229460AbjBHSTV (ORCPT ); Wed, 8 Feb 2023 13:19:21 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18011113C7 for ; Wed, 8 Feb 2023 10:19:21 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 9C0FA6178B for ; Wed, 8 Feb 2023 18:19:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7343FC433D2; Wed, 8 Feb 2023 18:19:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675880360; bh=6KoBeMpeRHFeimH5d0ziYXzYBp1yUeV/0hV0eN2Wxyg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qjh1vN3mKT0iPCq+xThdF1HLZpgWOw5GP4vdzmO6bRJ7aSatMSwkhFvvb4bZg5doD vpLq1v+rzaJRdQ2An0Vm1k4xWvT8QSW0EQgQf8BKyH8WfrP7136Xk8N40bJcl8QrrX mx3gYHqtfFMcNAKz0+HjICOgbgvnfabMgYXKTWWlJyk7xlohRzarr8qubU8tsc7DNp vCxCNYYtOJCXB1ya/s8vJtNwiF9fnCiQ4sVFLeYiqa5gCjsX2YZAiiJDP0NRFONGcq vyjZ7F37ftrL2DqY8GD/US9fF5g/FjtKnOFZnvEq/82wWaS5+KHiWXWH7xcsTJgIFW eq12Ci6e/DOFw== Date: Wed, 8 Feb 2023 18:19:14 +0000 From: Conor Dooley To: Conor Dooley Cc: Andy Chiu , linux-riscv@lists.infradead.org, palmer@dabbelt.com, anup@brainfault.org, atishp@atishpatra.org, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, vineetg@rivosinc.com, greentime.hu@sifive.com, guoren@linux.alibaba.com, Paul Walmsley , Albert Ou Subject: Re: [PATCH -next v13 19/19] riscv: Enable Vector code to be built Message-ID: References: <20230125142056.18356-1-andy.chiu@sifive.com> <20230125142056.18356-20-andy.chiu@sifive.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="gyvV7XIdJDtwPXYD" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org --gyvV7XIdJDtwPXYD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hey Andy, On Mon, Jan 30, 2023 at 08:13:20AM +0000, Conor Dooley wrote: > On Mon, Jan 30, 2023 at 03:46:32PM +0800, Andy Chiu wrote: > > On Thu, Jan 26, 2023 at 5:04 AM Conor Dooley wrote: > > > Firstly, no-implicit-float is a CFLAG, so why add it to march? > > I placed it in march because I thought we need the flag in vdso. And, > > KBUILD_CFLAGS is not enough for vdso. However, I think we don't need > > this flag in vdso since it is run in user space anyway. > > > There is an existing patch on the list for enabling this flag, but I > > > recall Palmer saying that it was not actually needed? > > The flag is needed for clang builds to prevent auto-vectorization from > > using V in the kernel code [1]. > >=20 > > > Palmer, do you remember why that was? > > The discussion[2] suggested that we need this flag, IIUC. But somehow > > the patch did make it into the tree. >=20 > I know, in [1] I left an R-b as the patch seemed reasonable to me. > Palmer mentioned some reason for not thinking it was actually needed but > not on-list, so I was hoping he'd comment! Palmer replied there today with his rationale & an expectation that we do the same thing for vector as we did for float: https://lore.kernel.org/linux-riscv/mhng-4c71ada6-003c-414f-9a74-efa3ccd285= 6b@palmer-ri-x1c9/T/#m366779709bbcf7672b5277b3bb27a7d6ce6c6115 >=20 > And I suppose, it never got any further attention as it isn't needed by > any in-tree code? >=20 > > [1]https://lore.kernel.org/all/CAOnJCULtT-y9vo6YhW7bW9XyKRdod-hvFfr02jH= VamR_LcsKdA@mail.gmail.com/ > > [2]https://lore.kernel.org/all/20221216185012.2342675-1-abdulras@google= =2Ecom/ Cheers, Conor. --gyvV7XIdJDtwPXYD Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCY+PnogAKCRB4tDGHoIJi 0uJ7AQDYZ/e40tjcGorJ/ALeoRnKAUyci3t2IcqRT1xoAD16dgEA7cSgEiEZ6h6l r1xFWeLAvcre2pZxf/YPY7NXXWrhzAQ= =9EzO -----END PGP SIGNATURE----- --gyvV7XIdJDtwPXYD-- 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5F4C0C636D3 for ; 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Wed, 08 Feb 2023 18:19:24 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pPp2P-00GafT-PA; Wed, 08 Feb 2023 18:19:23 +0000 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 dfw.source.kernel.org (Postfix) with ESMTPS id 961A161785; Wed, 8 Feb 2023 18:19:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7343FC433D2; Wed, 8 Feb 2023 18:19:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675880360; bh=6KoBeMpeRHFeimH5d0ziYXzYBp1yUeV/0hV0eN2Wxyg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qjh1vN3mKT0iPCq+xThdF1HLZpgWOw5GP4vdzmO6bRJ7aSatMSwkhFvvb4bZg5doD vpLq1v+rzaJRdQ2An0Vm1k4xWvT8QSW0EQgQf8BKyH8WfrP7136Xk8N40bJcl8QrrX mx3gYHqtfFMcNAKz0+HjICOgbgvnfabMgYXKTWWlJyk7xlohRzarr8qubU8tsc7DNp vCxCNYYtOJCXB1ya/s8vJtNwiF9fnCiQ4sVFLeYiqa5gCjsX2YZAiiJDP0NRFONGcq vyjZ7F37ftrL2DqY8GD/US9fF5g/FjtKnOFZnvEq/82wWaS5+KHiWXWH7xcsTJgIFW eq12Ci6e/DOFw== Date: Wed, 8 Feb 2023 18:19:14 +0000 From: Conor Dooley To: Conor Dooley Cc: Andy Chiu , linux-riscv@lists.infradead.org, palmer@dabbelt.com, anup@brainfault.org, atishp@atishpatra.org, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, vineetg@rivosinc.com, greentime.hu@sifive.com, guoren@linux.alibaba.com, Paul Walmsley , Albert Ou Subject: Re: [PATCH -next v13 19/19] riscv: Enable Vector code to be built Message-ID: References: <20230125142056.18356-1-andy.chiu@sifive.com> <20230125142056.18356-20-andy.chiu@sifive.com> MIME-Version: 1.0 In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230208_101921_935861_73203C54 X-CRM114-Status: GOOD ( 24.61 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============6376684334746837138==" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org --===============6376684334746837138== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="gyvV7XIdJDtwPXYD" Content-Disposition: inline --gyvV7XIdJDtwPXYD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hey Andy, On Mon, Jan 30, 2023 at 08:13:20AM +0000, Conor Dooley wrote: > On Mon, Jan 30, 2023 at 03:46:32PM +0800, Andy Chiu wrote: > > On Thu, Jan 26, 2023 at 5:04 AM Conor Dooley wrote: > > > Firstly, no-implicit-float is a CFLAG, so why add it to march? > > I placed it in march because I thought we need the flag in vdso. And, > > KBUILD_CFLAGS is not enough for vdso. However, I think we don't need > > this flag in vdso since it is run in user space anyway. > > > There is an existing patch on the list for enabling this flag, but I > > > recall Palmer saying that it was not actually needed? > > The flag is needed for clang builds to prevent auto-vectorization from > > using V in the kernel code [1]. > >=20 > > > Palmer, do you remember why that was? > > The discussion[2] suggested that we need this flag, IIUC. But somehow > > the patch did make it into the tree. >=20 > I know, in [1] I left an R-b as the patch seemed reasonable to me. > Palmer mentioned some reason for not thinking it was actually needed but > not on-list, so I was hoping he'd comment! Palmer replied there today with his rationale & an expectation that we do the same thing for vector as we did for float: https://lore.kernel.org/linux-riscv/mhng-4c71ada6-003c-414f-9a74-efa3ccd285= 6b@palmer-ri-x1c9/T/#m366779709bbcf7672b5277b3bb27a7d6ce6c6115 >=20 > And I suppose, it never got any further attention as it isn't needed by > any in-tree code? >=20 > > [1]https://lore.kernel.org/all/CAOnJCULtT-y9vo6YhW7bW9XyKRdod-hvFfr02jH= VamR_LcsKdA@mail.gmail.com/ > > [2]https://lore.kernel.org/all/20221216185012.2342675-1-abdulras@google= =2Ecom/ Cheers, Conor. --gyvV7XIdJDtwPXYD Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCY+PnogAKCRB4tDGHoIJi 0uJ7AQDYZ/e40tjcGorJ/ALeoRnKAUyci3t2IcqRT1xoAD16dgEA7cSgEiEZ6h6l r1xFWeLAvcre2pZxf/YPY7NXXWrhzAQ= =9EzO -----END PGP SIGNATURE----- --gyvV7XIdJDtwPXYD-- --===============6376684334746837138== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv --===============6376684334746837138==--