From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) by sourceware.org (Postfix) with ESMTP id EBAF43857C57 for ; Mon, 6 Jul 2020 10:45:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org EBAF43857C57 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-322-KkcGbw68NNOE7aICHPALIw-1; Mon, 06 Jul 2020 06:45:13 -0400 X-MC-Unique: KkcGbw68NNOE7aICHPALIw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 09BB51005510; Mon, 6 Jul 2020 10:45:12 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-112-118.ams2.redhat.com [10.36.112.118]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5C1935D9E4; Mon, 6 Jul 2020 10:45:11 +0000 (UTC) From: Florian Weimer To: "H.J. Lu" Cc: libc-alpha@sourceware.org Subject: Re: V7: [PATCH 1/2] x86: Support usable check for all CPU features References: <20200630043529.739181-1-hjl.tools@gmail.com> <20200630043529.739181-2-hjl.tools@gmail.com> <20200704171752.GA645968@gmail.com> Date: Mon, 06 Jul 2020 12:45:09 +0200 In-Reply-To: <20200704171752.GA645968@gmail.com> (H. J. Lu's message of "Sat, 4 Jul 2020 10:17:52 -0700") Message-ID: <878sfw6hxm.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 06 Jul 2020 10:45:16 -0000 * H. J. Lu: > + /* Copy the cpuid array to the usable array. */ > + unsigned int i; > + for (i = 0; i < COMMON_CPUID_INDEX_MAX; i++) > + cpu_features->features[i].usable = cpu_features->features[i].cpuid; > + > + /* Clear the usable bits which require OS support. */ > + CPU_FEATURE_UNSET (cpu_features, FMA); > + CPU_FEATURE_UNSET (cpu_features, AVX); > + CPU_FEATURE_UNSET (cpu_features, F16C); > + CPU_FEATURE_UNSET (cpu_features, AVX2); > + CPU_FEATURE_UNSET (cpu_features, AVX512F); > + CPU_FEATURE_UNSET (cpu_features, AVX512DQ); > + CPU_FEATURE_UNSET (cpu_features, AVX512_IFMA); > + CPU_FEATURE_UNSET (cpu_features, AVX512PF); > + CPU_FEATURE_UNSET (cpu_features, AVX512ER); > + CPU_FEATURE_UNSET (cpu_features, AVX512CD); > + CPU_FEATURE_UNSET (cpu_features, AVX512BW); > + CPU_FEATURE_UNSET (cpu_features, AVX512VL); > + CPU_FEATURE_UNSET (cpu_features, AVX512_VBMI); > + CPU_FEATURE_UNSET (cpu_features, PKU); > + CPU_FEATURE_UNSET (cpu_features, AVX512_VBMI2); > + CPU_FEATURE_UNSET (cpu_features, VAES); > + CPU_FEATURE_UNSET (cpu_features, VPCLMULQDQ); > + CPU_FEATURE_UNSET (cpu_features, AVX512_VNNI); > + CPU_FEATURE_UNSET (cpu_features, AVX512_BITALG); > + CPU_FEATURE_UNSET (cpu_features, AVX512_VPOPCNTDQ); > + CPU_FEATURE_UNSET (cpu_features, AVX512_4VNNIW); > + CPU_FEATURE_UNSET (cpu_features, AVX512_4FMAPS); > + CPU_FEATURE_UNSET (cpu_features, AVX512_VP2INTERSECT); > + CPU_FEATURE_UNSET (cpu_features, AMX_BF16); > + CPU_FEATURE_UNSET (cpu_features, AMX_TILE); > + CPU_FEATURE_UNSET (cpu_features, AMX_INT8); > + CPU_FEATURE_UNSET (cpu_features, XOP); > + CPU_FEATURE_UNSET (cpu_features, FMA4); > + CPU_FEATURE_UNSET (cpu_features, XSAVEC); > + CPU_FEATURE_UNSET (cpu_features, AVX512_BF16); This is not future-proof because we do not know which new features will require OS support, too. I think the sense has to be reversed, copying only the known flags. Thanks, Florian