From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by sourceware.org (Postfix) with ESMTP id 2DDDC3870849 for ; Mon, 28 Sep 2020 14:47:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 2DDDC3870849 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-576-hi-CIwBcNVSuhJkWjc9fWg-1; Mon, 28 Sep 2020 10:47:34 -0400 X-MC-Unique: hi-CIwBcNVSuhJkWjc9fWg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0D30A1868400; Mon, 28 Sep 2020 14:47:33 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-114-84.ams2.redhat.com [10.36.114.84]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5438D60C11; Mon, 28 Sep 2020 14:47:32 +0000 (UTC) From: Florian Weimer To: "H.J. Lu" Cc: "H.J. Lu via Libc-alpha" Subject: Re: [PATCH 1/4] x86: Initialize CPU info via IFUNC relocation [BZ 26203] References: <20200918160709.949608-1-hjl.tools@gmail.com> <20200918160709.949608-2-hjl.tools@gmail.com> <87imby6obw.fsf@oldenburg2.str.redhat.com> <87y2ku574k.fsf@oldenburg2.str.redhat.com> <87lfgu56c8.fsf@oldenburg2.str.redhat.com> Date: Mon, 28 Sep 2020 16:47:30 +0200 In-Reply-To: (H. J. Lu's message of "Mon, 28 Sep 2020 07:39:16 -0700") Message-ID: <87pn663qm5.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.8 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_H5, 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, 28 Sep 2020 14:47:37 -0000 * H. J. Lu: > On Mon, Sep 28, 2020 at 7:22 AM Florian Weimer wrote: >> >> * H. J. Lu: >> >> > We want to call init_cacheinfo as early as possible. __libc_early_init is >> > still too late. >> >> My point is that we should call it from IFUNC resolvers that need it, >> and from __libc_early_init. That should cover all cases, no? > > Why call it from __libc_early_init after it has been called by > IFUNC reloc? IFUNC relocations are processed before > __libc_early_init is called. IFUNC relocations might not existing in a --disable-multi-arch build, but it may still need the cacheinfo data if the hard-coded implementations need them. We would still run the IFUNC resolver for the artificial IFUNC resolver with its function pointer, but: My concern is that you seem to have a specific ordering dependency on IFUNC resolvers, and I would like to get rid of that: Initialize the necessary data on demand (for string function selection), and during __libc_early_init for potential use from string functions. I hope this clarifies what I'm looking for. Please let me know if this is not reasonable. Thanks, Florian -- Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn, Commercial register: Amtsgericht Muenchen, HRB 153243, Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill