From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3CB372F870 for ; Wed, 15 May 2024 14:34:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715783681; cv=none; b=tOrQok4S2aObunhm80xofWoluWNfKHvFCvE7eQ48+sSfXJQCQUesBklpKCHMwfJpuKr8dY1yqRmA1o3w8tyY9lmHgeaG+qo9K0Sfnf0/CmQhISuH+k3LZuD5+h2UWvfOg0wKxKDgH5ogj3nWdpgpQECq/pTVLFARg7Pc0U9LCtQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715783681; c=relaxed/simple; bh=j/XnY4Ou9a6eJs+MOmPai9peUKhp5Tll7YO5cG6SzzY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lEpDjsLjoBBggP/eclz/hK6rBfz5EKcIi1T2PpS7lmAlNaF/c4L668L4uFplcqdhyv4shv/i8ufDtMaKJMfENkofGfikhNqkwJuymm7GYModcX/1RfNl1dPmtb4IR+ZmBCwHoZlQieSBRbwFsobYEmkTa394rGco0UTo174U3ns= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UUEUoATW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UUEUoATW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C58DC4AF07; Wed, 15 May 2024 14:34:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715783680; bh=j/XnY4Ou9a6eJs+MOmPai9peUKhp5Tll7YO5cG6SzzY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UUEUoATWfr34myIc0rnXR0ELSQlSHOVVtrffGh6wdBaiV1iMv8fn/Dylc4VdJ7eIa z/IFSMUy5AAksOk8fPYFcD+kchrQ7y3ZuqZNyKrqyK3WKhfCnBGUNFqGE5++MQtMe9 UWv8nfk3G7wo27kskoEEljP1JbNJa912uxc7ud7NiI9Dqq3CjYG1CXz82ykprcqjcC XJbjW1RX5pJ/KbOjpoC8Dh/uCKH/UBs1EkGLSo9sWLNnh7y2agam9IlM7QXGabTwn7 uxFm+Y7weh8PId23dRle1mBqIN8DBiLDmd/w/HHsHJzZu9tb5esgvWVkYo0Zs1n4W/ bIqV0TDUTF60Q== Date: Wed, 15 May 2024 15:34:36 +0100 From: Conor Dooley To: Charlie Jenkins Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Conor Dooley , Song Liu , Xi Wang , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , =?iso-8859-1?Q?Cl=E9ment_L=E9ger?= , Jessica Clarke , Andy Chiu , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/8] riscv: Add PLATFORM_MAY_SUPPORT_RISCV_ISA_V Kconfig option Message-ID: <20240515-subpar-implement-6fcf333ce9d3@spud> References: <20240507-compile_kernel_with_extensions-v2-0-722c21c328c6@rivosinc.com> <20240507-compile_kernel_with_extensions-v2-2-722c21c328c6@rivosinc.com> <20240510-earthly-regress-7a8c8dba55db@spud> <20240510-pursuable-oppose-e0b8430271f6@spud> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ZKjQ/5BhNQvy54yM" Content-Disposition: inline In-Reply-To: <20240510-pursuable-oppose-e0b8430271f6@spud> --ZKjQ/5BhNQvy54yM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 10, 2024 at 11:26:22PM +0100, Conor Dooley wrote: > On Fri, May 10, 2024 at 02:43:10PM -0700, Charlie Jenkins wrote: > > On Fri, May 10, 2024 at 09:43:33PM +0100, Conor Dooley wrote: > > > Hey Charlie, > > >=20 > > > On Tue, May 07, 2024 at 06:36:28PM -0700, Charlie Jenkins wrote: > > > > Current versions of the kernel add "v" to the march and then immeid= ately > > > > filter it out such that "v" is not passed to CFLAGS. Instead of do= ing > > > > this filtering, code blocks in the kernel that want to use vector > > > > assembly have been changed to locally enable vector (using ".option > > > > arch, +v"). > > >=20 > > > Other content in the series aside, since this is a change that could = be > > > made independently of the main series objectives, I figured it was wo= rth > > > pointing out that this is not a change without downsides: I think that > > > it would drop support for vector with most versions of LLVM as > > > .option arch support there is much more recent thing than it is for g= cc. > > > Off the top of my head I don't know exactly the versions involved, but > > > it is something like LLVM-14 supports vector but only LLVM-17 and lat= er > > > supports .option arch. > >=20 > > Toolchain incompatibilities are always fun. It does look like .option > > arch was introduced in LLVM-17. That would be a regression. We do use > > .option arch for every other extension, but vector was treated special > > when it was introduced unfortunately so maybe we have to live with the > > weird march parsing hack. >=20 > I wrote out a long message about the history of some of this, but right > at the end I was scrolling through my chat logs with Andy and realised > we actually did make it depend on AS_HAS_OPTION_ARCH, so it should be > safe to do without regressing anything. I didn't notice in the diff that > the AS_HAS_OPTION_ARCH was a movement, not an addition. Maybe Andy knows > why, despite the dependency on the assembler having it, we didn't use it > everywhere. And while I remember, the bits of this doing the .option arch conversion should be (IMO) split into a different patch to anything dealing with Kconfig options etc. Cheers, Conor. --ZKjQ/5BhNQvy54yM Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZkTH/AAKCRB4tDGHoIJi 0szcAQDBzSfhT6hyr1aMrYz0B6QSH4FaqNn9GXsP9yi3ZgA6aAEAqEXaBTtCPjux 6DPqxss1XZfW3iAObMh2xDZIwaJlnQk= =+Ld6 -----END PGP SIGNATURE----- --ZKjQ/5BhNQvy54yM--