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 6ADE62206AC for ; Fri, 6 Mar 2026 18:50:25 +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=1772823025; cv=none; b=Zf7/pS0hbGiVe0RnclDeDBKCKBUVra3v/RrVRsh2Gwgjn8zozKyBF0ef8GHV0R2aMH+1DcZOCv1rigEc37+W6romw0MIyB4k+RT9/VQ8+6zTJXK2I5wtiWBYmOanKr92DhNVSYc5ON6QAk7mvkQfsW7fevWsS0vyr46gjb5N9J0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772823025; c=relaxed/simple; bh=CXf+qiTuDfOz6CfipA7SxNP2+LULMzJLNMe3liFGXl8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tNESVlzGy56iFacHRYNH59XpGwskbt2eYFAU+63elTHkZQirCjFkfJbR+IKy8ZDiOaGGt6pWzZgUNDNkNS15znfvF2pN8dsbbPSKHbaKSSEUU0N+D3Tl4n57hfqvgp7eMtV3zKFAj9kcuLXeRvINwulPMK9qG9sQ07b7XhZnRnY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aDLXsQk9; 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="aDLXsQk9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80338C4CEF7; Fri, 6 Mar 2026 18:50:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772823025; bh=CXf+qiTuDfOz6CfipA7SxNP2+LULMzJLNMe3liFGXl8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aDLXsQk9ocHR6NuQ8rXOcdGiBSxfWF61GDyxN1m1bXeXtgz9zOlCePO1gf1n0mDaD xze4NkFofoZlfEj9uaLLiPZ3KprYe+CkRonzasZDz9VPPsaVLhGAS7HotmRhgfAhjG 4is/vp7y1kg+kXM++z28Khmt4lXamB6sAZl2jmxdvS/YKCZJLhXzuw0CVPiYtgq6xr 1J6NAk3kR2Fxqt0t638ugju3KpeRsiAwQF5wb+FMLVJ5Ve0W0q3iRRGQjg4W/Jk/lN UPylw0+h1WA0N4WZe4JggEAqRQOZSkB7KmNGuXc9XObgRzTM8gRcRgQPMB+VBPpi/H E3PcAkA/ANOhA== Date: Fri, 6 Mar 2026 18:50:20 +0000 From: Conor Dooley To: Andrew Jones Cc: Guodong Xu , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, kvm-riscv@lists.infradead.org, Paul Walmsley , Palmer Dabbelt , Anup Patel , =?iso-8859-1?Q?Cl=E9ment_L=E9ger?= , Conor Dooley , Charlie Jenkins , Charlie Jenkins , Samuel Holland Subject: Re: [RFC PATCH v1 04/11] riscv: Add B to hwcap Message-ID: <20260306-extradite-vexingly-707b5633ef03@spud> References: <20260206002349.96740-1-andrew.jones@oss.qualcomm.com> <20260206002349.96740-5-andrew.jones@oss.qualcomm.com> 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-sha512; protocol="application/pgp-signature"; boundary="/AcnNhLeLmSnANzW" Content-Disposition: inline In-Reply-To: --/AcnNhLeLmSnANzW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Mar 06, 2026 at 12:27:50PM -0600, Andrew Jones wrote: > On Fri, Mar 06, 2026 at 10:17:19AM +0800, Guodong Xu wrote: > > + /* > > + * B is functionally a bundle (Zba + Zbb + Zbs, > > + * no additional instructions). We use SUPERSET > > + * instead of BUNDLE because B needs a valid ext > > + * id for isa2hwcap[] to set COMPAT_HWCAP_ISA_B. What's the actual rationale for it working like that? Why shouldn't bundles appear in cpuinfo etc, I forget entirely why we did it this way. Feels like it'd be easier for users, no? 2023 me might disagree, but 2026 me doesn't see the value in hiding these extensions. All I can think of was me being very negative, and hedging against bad software checking for zkn and not checking for the subsets, and breaking if the dt listed the entire subset but not zkn. That, or not wanting to implement code that looked for subset extensions and populated the relevant bundle if the bundle itself was missing but all components were there. --/AcnNhLeLmSnANzW Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCaash0wAKCRB4tDGHoIJi 0iIAAP9oTSvcmB5/lTwaR52b6Bb1IZv+M5XS98rKIMQhw6YIUAEAjhGUgg041nll NfMwiNs7eX/UD6TIlfQOyt46KoyXWw8= =E4vH -----END PGP SIGNATURE----- --/AcnNhLeLmSnANzW--