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 9B0F1C433F5 for ; Tue, 19 Apr 2022 13:58:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345135AbiDSOBQ (ORCPT ); Tue, 19 Apr 2022 10:01:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344830AbiDSOBH (ORCPT ); Tue, 19 Apr 2022 10:01:07 -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 25F0A38DBD; Tue, 19 Apr 2022 06:58:25 -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 AA07461693; Tue, 19 Apr 2022 13:58:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73840C385A5; Tue, 19 Apr 2022 13:58:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650376704; bh=sGN5CWJMdVz20am6iOdFUlCdx+o7gih1dOCoJNfeTSA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oVlUbHyYZrYiHdaKXoEt9i5RnHm0Tqyb/SexzIytdTBl35qudDnnNVGa1i2jiMyXC EiT2Occbmv0R6ejqmALFC41DISyln6ioVQUxOiobhGuHEBRGmk895qCiGT3llLpgCS DuAciLfgcCBmA6K9EUwaISHek/9dhN+cIDcMCx7WdivxTx1MPnQF5HZzzZvZ9Cwnvx 62Uki5HSRL/zTuf2lvogFTfDR6Lp4/b7t23mS7PaWA5w9XWLhuNcQNFlsl8HGlm8T/ oQ9nz++paPpgY3+W/RpjtfPgw3zZRXV/15bYCfriFjjuEbhwJljAk7bDa/MtAG3UYh Z0199/1sNdoLw== Date: Tue, 19 Apr 2022 14:58:17 +0100 From: Mark Brown To: Tianjia Zhang Cc: Will Deacon , Catalin Marinas , Jonathan Corbet , Marc Zyngier , Joey Gouly , Vincenzo Frascino , Arnd Bergmann , Anshuman Khandual , Fuad Tabba , Mark Rutland , Vladimir Murzin , James Morse , Suzuki K Poulose , Mathieu Poirier , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64/sme: Add hwcap for Scalable Matrix Extension Message-ID: References: <20220414115544.36204-1-tianjia.zhang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="y7+zdXbMAYrYfLfn" Content-Disposition: inline In-Reply-To: X-Cookie: That's what she said. Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --y7+zdXbMAYrYfLfn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Apr 15, 2022 at 10:25:33AM +0800, Tianjia Zhang wrote: > On 4/14/22 8:02 PM, Mark Brown wrote: > > On Thu, Apr 14, 2022 at 07:55:44PM +0800, Tianjia Zhang wrote: > > Why add something independently, especially given that there is no way > > for userspace to do anything constructive with the feature without the > > rest of the kernel support? Any attempt to use SME instructions without > > kernel support will trap and generate a SIGILL even if the feature is > > present in hardware. > Great job, I encountered the issue of invalid REVD (requires FEAT_SME) > instruction when developing SVE2 programs, so I plan to gradually > support SME in the kernel, thanks for your contribution, you can ignore > my patch. I see. Unfortunately all the new registers mean that we really need to define all the ABI as soon as we enable anything and the only thing we can really skip out on when doing initial enablement is KVM (which I have in fact skipped for the time being, I'll look at that at some point after the initial support is landed). > In addition, I would like to ask a question, whether there is an > alternative SVE2 instruction for the REVD instruction that can complete > this operation, if the machine does not support SME. I'm not aware of anything, but I am mostly focused on the OS support rather than any of the actual mathematical operations that are more the point of these architecture features so I might be missing something. > > Do you have a system with SME that you're trying to use? Review/testing > > on the current series would be appreciated. > Unfortunately, the value currently read by my machine ID_AA64PFR1_EL1 > register is 0x121. It seems that the hardware does not support SME. Is > there any other help I can provide? Other than verifying that the series doesn't cause trouble for systems without SME=20 --y7+zdXbMAYrYfLfn Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmJev/gACgkQJNaLcl1U h9D6Pwf5AXCOiooQjnPnliTaNN7/AbtJt2IfDB/g6sI7mk8sbxHv9T62E2BNQW9K 7pG00JpxzBV/cjBTdT0JKgAK4Ze5I0OE8kO6rW2at9n6sKHKBTr3Adbu52KNs6CI wiWlZkTu6RVfy/TKHwsaw93QSJtSbo8LamAbADXSAcZ2BpdVsUvZsaVho/uLEth4 lmd8iCnXhCpZrsyMuRx8sx6FSgizBGtxhWyhxK+1DqN8zEQxE2j2IE7SQiq9k0eI y3/ZF+cwQnAssmJQxS+smIdH6uBFpowl2t5CcUkE2rKIvF69rvun8tSHHDBnv1cK QTE+0+iGFwrWMHo0H63sSeZGs3qMig== =6+y1 -----END PGP SIGNATURE----- --y7+zdXbMAYrYfLfn-- 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 C4DE1C433F5 for ; Tue, 19 Apr 2022 14:57:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=iDncvkQFSlCxKPBrbPXr8BpE2c/g8bnHhZ1Leml9aEQ=; b=2FgVBDajzwAlczPqD0iO5gbvSQ jQId3UwmY3QFatg9nE2RL7jeX85MvJGlq26rdR9TlX9QT5IKyPzyWgT9Y3fqzU6dZvhBgLnkug8n9 27LNb5yAjrRK94kptkyIA8EpiX0HSqaCA0oc7U2jE5vsKQEQU6F4BFYqA+o7ZxFZTz9JGtJdas+On ce+GLv9TRhAF+1plyvvBBtOOEEPazZkrElysA9Ax1OA7H6eW4zANKbsm0cd+v4UwjVZIi83Pw8u8N B4cMcGH+arPzwF8XyDJEpkZv33Yy/fbPC4DdFCr0tH8t6Kiq+tjls9vtPVzJERIy3FeVti/H9ReBT fJWnyLIw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngpGP-004ROP-44; Tue, 19 Apr 2022 14:55:33 +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 1ngoNC-0044O0-6R for linux-arm-kernel@lists.infradead.org; Tue, 19 Apr 2022 13:58:31 +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 A6BCC61698; Tue, 19 Apr 2022 13:58:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73840C385A5; Tue, 19 Apr 2022 13:58:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650376704; bh=sGN5CWJMdVz20am6iOdFUlCdx+o7gih1dOCoJNfeTSA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oVlUbHyYZrYiHdaKXoEt9i5RnHm0Tqyb/SexzIytdTBl35qudDnnNVGa1i2jiMyXC EiT2Occbmv0R6ejqmALFC41DISyln6ioVQUxOiobhGuHEBRGmk895qCiGT3llLpgCS DuAciLfgcCBmA6K9EUwaISHek/9dhN+cIDcMCx7WdivxTx1MPnQF5HZzzZvZ9Cwnvx 62Uki5HSRL/zTuf2lvogFTfDR6Lp4/b7t23mS7PaWA5w9XWLhuNcQNFlsl8HGlm8T/ oQ9nz++paPpgY3+W/RpjtfPgw3zZRXV/15bYCfriFjjuEbhwJljAk7bDa/MtAG3UYh Z0199/1sNdoLw== Date: Tue, 19 Apr 2022 14:58:17 +0100 From: Mark Brown To: Tianjia Zhang Cc: Will Deacon , Catalin Marinas , Jonathan Corbet , Marc Zyngier , Joey Gouly , Vincenzo Frascino , Arnd Bergmann , Anshuman Khandual , Fuad Tabba , Mark Rutland , Vladimir Murzin , James Morse , Suzuki K Poulose , Mathieu Poirier , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64/sme: Add hwcap for Scalable Matrix Extension Message-ID: References: <20220414115544.36204-1-tianjia.zhang@linux.alibaba.com> MIME-Version: 1.0 In-Reply-To: X-Cookie: That's what she said. X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220419_065830_374416_83B64842 X-CRM114-Status: GOOD ( 29.93 ) X-BeenThere: linux-arm-kernel@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="===============0754593818726248258==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============0754593818726248258== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="y7+zdXbMAYrYfLfn" Content-Disposition: inline --y7+zdXbMAYrYfLfn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Apr 15, 2022 at 10:25:33AM +0800, Tianjia Zhang wrote: > On 4/14/22 8:02 PM, Mark Brown wrote: > > On Thu, Apr 14, 2022 at 07:55:44PM +0800, Tianjia Zhang wrote: > > Why add something independently, especially given that there is no way > > for userspace to do anything constructive with the feature without the > > rest of the kernel support? Any attempt to use SME instructions without > > kernel support will trap and generate a SIGILL even if the feature is > > present in hardware. > Great job, I encountered the issue of invalid REVD (requires FEAT_SME) > instruction when developing SVE2 programs, so I plan to gradually > support SME in the kernel, thanks for your contribution, you can ignore > my patch. I see. Unfortunately all the new registers mean that we really need to define all the ABI as soon as we enable anything and the only thing we can really skip out on when doing initial enablement is KVM (which I have in fact skipped for the time being, I'll look at that at some point after the initial support is landed). > In addition, I would like to ask a question, whether there is an > alternative SVE2 instruction for the REVD instruction that can complete > this operation, if the machine does not support SME. I'm not aware of anything, but I am mostly focused on the OS support rather than any of the actual mathematical operations that are more the point of these architecture features so I might be missing something. > > Do you have a system with SME that you're trying to use? Review/testing > > on the current series would be appreciated. > Unfortunately, the value currently read by my machine ID_AA64PFR1_EL1 > register is 0x121. It seems that the hardware does not support SME. Is > there any other help I can provide? Other than verifying that the series doesn't cause trouble for systems without SME=20 --y7+zdXbMAYrYfLfn Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmJev/gACgkQJNaLcl1U h9D6Pwf5AXCOiooQjnPnliTaNN7/AbtJt2IfDB/g6sI7mk8sbxHv9T62E2BNQW9K 7pG00JpxzBV/cjBTdT0JKgAK4Ze5I0OE8kO6rW2at9n6sKHKBTr3Adbu52KNs6CI wiWlZkTu6RVfy/TKHwsaw93QSJtSbo8LamAbADXSAcZ2BpdVsUvZsaVho/uLEth4 lmd8iCnXhCpZrsyMuRx8sx6FSgizBGtxhWyhxK+1DqN8zEQxE2j2IE7SQiq9k0eI y3/ZF+cwQnAssmJQxS+smIdH6uBFpowl2t5CcUkE2rKIvF69rvun8tSHHDBnv1cK QTE+0+iGFwrWMHo0H63sSeZGs3qMig== =6+y1 -----END PGP SIGNATURE----- --y7+zdXbMAYrYfLfn-- --===============0754593818726248258== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============0754593818726248258==--