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 061BE1E51EE; Thu, 9 Oct 2025 16:53:22 +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=1760028804; cv=none; b=liKDnvqzvKCkeP1XIosbGtTbKjZ5lEDLef7smBQBcqibzCknKmfYzvT229F3My9M8vbRyhHwFmZdX9lC7d6BiVM8V7UkmOOwicrFH0PWd5Q+fBcNR4SO/KO7HlZcX7L9YpMgVm8eMcwbaRUqNHaIsRIIvIO6/S7nf31JE7IalRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760028804; c=relaxed/simple; bh=s3EeI5Z56afA2rXL7zIjK2ku2OOzEBiB/kUemFUGtIY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RrTaVznqPlXlVf0iJxqzV9tvcerUpQDEfomTUL1+/L+PC/hdsp2Nhq8UmYEL2ICFBYV7O8cjpdV25VAeVvVLUQmsFwmlpb1WfoQDWxSw0w4Pbdzcs3g1YsT2Fg82r2ZMQIhxSK3llWtZamAYZxb8rpAt8aogvApdpR8cz/xIgEE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eoF+m5hs; 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="eoF+m5hs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 246BDC4CEE7; Thu, 9 Oct 2025 16:53:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760028802; bh=s3EeI5Z56afA2rXL7zIjK2ku2OOzEBiB/kUemFUGtIY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eoF+m5hsCRlnJ3mziERlyxeSUZkpA+Uq3/wyy0nW6KS76Qfb+DLrB7hQ4iX52qBHG 7tXtaxX24wHY/VwV9QKXc/FiB2EJAmz5u+VKW8IEu1dmCUNunglycXeDQVoaBd7VdY dJzXhEOr48fU7PwHGyMy45putihKE4EoaFAvtrOVJ7FYK/LOCIiXQ6QvJFljBV3dXC 5lDb8tQRlWcItlQ+g9QOd+oI6bns4qp+WL2GQJP4+tUFU7s2GY/gsFpJdwkjJ4dKg3 bRNiLY4RVfWd+P6Ud/EfIwhG4WBQO0oJk5VxwnQC113R7E1j57jp6id5eK7q0kVWcT FJMxRKP14E4TQ== Date: Thu, 9 Oct 2025 17:53:14 +0100 From: Conor Dooley To: Yunhui Cui Cc: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com, peterz@infradead.org, jpoimboe@kernel.org, jbaron@akamai.com, ardb@kernel.org, willy@infradead.org, guoren@kernel.org, ziy@nvidia.com, akpm@linux-foundation.org, bjorn@rivosinc.com, ajones@ventanamicro.com, parri.andrea@gmail.com, cleger@rivosinc.com, yongxuan.wang@sifive.com, inochiama@gmail.com, samuel.holland@sifive.com, charlie@rivosinc.com, conor.dooley@microchip.com, yikming2222@gmail.com, andybnac@gmail.com, yury.norov@gmail.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH RFC] riscv: add support for Ziccid Message-ID: <20251009-secluded-writing-adefb1f71a72@spud> References: <20251009134514.8549-1-cuiyunhui@bytedance.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="nor471u/BfNy6yoJ" Content-Disposition: inline In-Reply-To: <20251009134514.8549-1-cuiyunhui@bytedance.com> --nor471u/BfNy6yoJ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 09, 2025 at 09:45:14PM +0800, Yunhui Cui wrote: > The Ziccid extension provides hardware synchronization between > Dcache and Icache. With this hardware support, there's no longer > a need to trigger remote hart execution of fence.i via IPI. >=20 > Signed-off-by: Yunhui Cui Actual correctness aside, in an RFC should you really state why this is an RFC and not just a v1 patch. You're missing a dt-binding change that's required for new extensions, that you'll need for v2. > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeatur= e.c > index 67b59699357da..2da82aa2dbf0a 100644 > --- a/arch/riscv/kernel/cpufeature.c > +++ b/arch/riscv/kernel/cpufeature.c > @@ -540,6 +540,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] =3D { > __RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT), > __RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT), > __RISCV_ISA_EXT_DATA(svvptc, RISCV_ISA_EXT_SVVPTC), > + __RISCV_ISA_EXT_DATA(ziccid, RISCV_ISA_EXT_ZICCID), > }; The comment about this structure reads: /* * The canonical order of ISA extension names in the ISA string is defined = in * chapter 27 of the unprivileged specification. * * Ordinarily, for in-kernel data structures, this order is unimportant but * isa_ext_arr defines the order of the ISA string in /proc/cpuinfo. * * The specification uses vague wording, such as should, when it comes to * ordering, so for our purposes the following rules apply: * * 1. All multi-letter extensions must be separated from other extensions b= y an * underscore. * * 2. Additional standard extensions (starting with 'Z') must be sorted aft= er * single-letter extensions and before any higher-privileged extensions. * * 3. The first letter following the 'Z' conventionally indicates the most * closely related alphabetical extension category, IMAFDQLCBKJTPVH. * If multiple 'Z' extensions are named, they must be ordered first by * category, then alphabetically within a category. * * 3. Standard supervisor-level extensions (starting with 'S') must be list= ed * after standard unprivileged extensions. If multiple supervisor-level * extensions are listed, they must be ordered alphabetically. * * 4. Standard machine-level extensions (starting with 'Zxm') must be listed * after any lower-privileged, standard extensions. If multiple * machine-level extensions are listed, they must be ordered * alphabetically. * * 5. Non-standard extensions (starting with 'X') must be listed after all * standard extensions. If multiple non-standard extensions are listed, = they * must be ordered alphabetically. * * An example string following the order is: * rv64imadc_zifoo_zigoo_zafoo_sbar_scar_zxmbaz_xqux_xrux * * New entries to this struct should follow the ordering rules described ab= ove. */ Cheers, Conor. --nor471u/BfNy6yoJ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCaOfoegAKCRB4tDGHoIJi 0hdSAP4mmjzLQiGeP2lXFFu31PWRRLqRQHE8ipZDJS96deFWTQD+PwyH70gg9y03 slIpEN0aUuJ9z2FpvqNH5MXCJurtAgE= =tcgM -----END PGP SIGNATURE----- --nor471u/BfNy6yoJ--