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 7C0C5C7EE22 for ; Thu, 11 May 2023 21:47:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233312AbjEKVrq (ORCPT ); Thu, 11 May 2023 17:47:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231376AbjEKVrp (ORCPT ); Thu, 11 May 2023 17:47:45 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 753133A93 for ; Thu, 11 May 2023 14:47:44 -0700 (PDT) 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 F1F6E65212 for ; Thu, 11 May 2023 21:47:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF5E4C433D2; Thu, 11 May 2023 21:47:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683841663; bh=N6lJFJqzV7ytXV6+rKvzLTpx6yPBkX401wQ/wXQJiW4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Wl4jlKhfsue4/c+zHUnLXabF7cR1b91X+0Z0SohLoB3xQfCNIeKpkTEOtl58tmT95 XIkYw3V6b9NROUr+rjpt7DpTXeftAsRn6BXaKbVCcmaehEZQ7wO8E6bg/a029tcowQ ey72wKPZEURG+TG+Bek/PzhY95qLydEe0IMV+wfQFl5MREW0QwxfgjLY5dTia0zvUq PT+HOLs0/U/1tt+5HbqigcHs1eBKPKs8RbOPEwi1U1fEDKJUTNNdJU/dmRgV3dv10Z 0ShNuEBMu+Ch/Mzy6wcYT89wFiyS3xf0PhQCuS7YXemz/SnOJdJ0tui/ENxsLKrL4L Ac774mfOgQwAQ== Date: Thu, 11 May 2023 22:47:38 +0100 From: Conor Dooley To: Atish Patra Cc: linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, Conor Dooley , Heiko Stuebner , Yangyu Chen , Conor Dooley , Rob Herring , Palmer Dabbelt , Krzysztof Kozlowski , Paul Walmsley , Andrew Jones Subject: Re: [RFC 0/6] Deprecate riscv,isa DT property? Message-ID: <20230511-punctuate-dinghy-0dd9be94270c@spud> References: <20230508-hypnotic-phobia-99598439d828@spud> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="KNnUOQ8SfmCZhf4A" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org --KNnUOQ8SfmCZhf4A Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 11, 2023 at 02:27:44PM -0700, Atish Patra wrote: > > The other thought I had was that perhaps some software may choose not to > > implement version x.y.0 of an extension and only support x.z.0, z > y > > for some reason. We'd want to refuse that extension if the extension is > > found, but the version is not listed as being something compatible with > > x.z.0, and while the ISA spec does say that the default assumption is > > 2p0 for unversioned extensions in its current form, I struggle to > > extrapolate that to extensions not currently part of the unpriv spec, > > but rather defined on their own. > > >=20 > That's a fair point. However, any new RVI ISA extension will only have v1= =2E0 > as per my knowledge. Any new feature will have to be part of a > different extension. > At least that was the plan discussed last year. That's more than last year at this point, and nothing has changed in the documentation! Talk's cheap, ehh? > https://github.com/riscv/riscv-isa-manual/issues/781#issuecomment-9832226= 55 >=20 > Are you aware of any discussion that changes this ? It's called "trust issues". I am far less worried about the addition of new features though than the removal of existing ones. Part of me fears for fence.i-less systems for example, but there would be other ways to bodge around the mess if it comes to pass. If we are *sure* that no extensions will modify features additively or subtractively, then this may not be needed at all & I can avoid having to bend dt-validate to my will. We have no guarantees for vendor extensions on that front either, they're free to do what they like w.r.t. versioning, no? --KNnUOQ8SfmCZhf4A Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZF1iegAKCRB4tDGHoIJi 0kU0AQDe4wPkJbvFunY7Hd7tVeEqB9Nx4RBMWPuYxZW9CGVh0wEA201Uii1iRlaK nSvwRBXu5EKO8fs96wDjwGzDo9UlRAQ= =BbjJ -----END PGP SIGNATURE----- --KNnUOQ8SfmCZhf4A--