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 632AAC433F5 for ; Fri, 15 Apr 2022 02:25:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348687AbiDOC2O (ORCPT ); Thu, 14 Apr 2022 22:28:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344697AbiDOC2M (ORCPT ); Thu, 14 Apr 2022 22:28:12 -0400 Received: from out199-1.us.a.mail.aliyun.com (out199-1.us.a.mail.aliyun.com [47.90.199.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 35B8685967; Thu, 14 Apr 2022 19:25:44 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=tianjia.zhang@linux.alibaba.com;NM=1;PH=DS;RN=18;SR=0;TI=SMTPD_---0VA5Fc8T_1649989538; Received: from 30.240.101.97(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0VA5Fc8T_1649989538) by smtp.aliyun-inc.com(127.0.0.1); Fri, 15 Apr 2022 10:25:40 +0800 Message-ID: Date: Fri, 15 Apr 2022 10:25:33 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH] arm64/sme: Add hwcap for Scalable Matrix Extension Content-Language: en-US To: Mark Brown 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 References: <20220414115544.36204-1-tianjia.zhang@linux.alibaba.com> From: Tianjia Zhang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, On 4/14/22 8:02 PM, Mark Brown wrote: > On Thu, Apr 14, 2022 at 07:55:44PM +0800, Tianjia Zhang wrote: > >> Allow userspace to detect support for SME (Scalable Matrix Extension) >> by providing a hwcap for it, using the official feature name FEAT_SME, >> declared in ARM DDI 0487H.a specification. > > There's already a hwcap for the core feature and all the subfeatures > added as part of the series I've been posting for SME: > > https://lore.kernel.org/linux-arm-kernel/20220408114328.1401034-1-broonie@kernel.org/ > > 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. 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. > > 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? Kind regards, Tianjia 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 5CF80C433F5 for ; Fri, 15 Apr 2022 02:26:56 +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: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=DDqwxmxqAfA3Ogbzz1sKn+B/kjW24J4P9RR+wDdDXIc=; b=lW9GvG5X4PW6qW mrrrixP/KaDi/iT1MQA/hmhp3jO9IaezMQibim/JIRMjv0Oy34HQ5mdHW5p4IX+vvFnvqmn91jhJo /VGlhHaJgx/twROkE2K7NLGuNr+OepHtfVXIvSXs86OUEiMKW0e+qc3UXZv7HWuNHWKW7QzCq8p8r xldzGFfsPtQV80SkDZLQisOzioKzmA9K8x/0/UgvNbQpiAMb469uT4FEuEWx7nGb3fxH6MkA0Ze/M 6RIyDTl/mdkTrL2hRf48GDOE3JT5YwASISdABp8qemjaH7Pxdst2w4B2D+isHJ4xiWkZ9gCxCN/8E DyV6WvwfMblioXPKHyHA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfBeg-0086l2-Ut; Fri, 15 Apr 2022 02:25:51 +0000 Received: from out199-15.us.a.mail.aliyun.com ([47.90.199.15]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfBed-0086ip-5N for linux-arm-kernel@lists.infradead.org; Fri, 15 Apr 2022 02:25:49 +0000 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R131e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04395; MF=tianjia.zhang@linux.alibaba.com; NM=1; PH=DS; RN=18; SR=0; TI=SMTPD_---0VA5Fc8T_1649989538; Received: from 30.240.101.97(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0VA5Fc8T_1649989538) by smtp.aliyun-inc.com(127.0.0.1); Fri, 15 Apr 2022 10:25:40 +0800 Message-ID: Date: Fri, 15 Apr 2022 10:25:33 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH] arm64/sme: Add hwcap for Scalable Matrix Extension Content-Language: en-US To: Mark Brown 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 References: <20220414115544.36204-1-tianjia.zhang@linux.alibaba.com> From: Tianjia Zhang In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220414_192547_526523_A51B2DB5 X-CRM114-Status: GOOD ( 20.35 ) 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mark, On 4/14/22 8:02 PM, Mark Brown wrote: > On Thu, Apr 14, 2022 at 07:55:44PM +0800, Tianjia Zhang wrote: > >> Allow userspace to detect support for SME (Scalable Matrix Extension) >> by providing a hwcap for it, using the official feature name FEAT_SME, >> declared in ARM DDI 0487H.a specification. > > There's already a hwcap for the core feature and all the subfeatures > added as part of the series I've been posting for SME: > > https://lore.kernel.org/linux-arm-kernel/20220408114328.1401034-1-broonie@kernel.org/ > > 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. 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. > > 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? Kind regards, Tianjia _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel