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 0B3F3387085D for ; Mon, 18 Jan 2021 20:14:24 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 0B3F3387085D 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-316-0YBsWTV8PDu92f0o287Gmg-1; Mon, 18 Jan 2021 15:14:22 -0500 X-MC-Unique: 0YBsWTV8PDu92f0o287Gmg-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 2697B806667; Mon, 18 Jan 2021 20:14:21 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-110.ams2.redhat.com [10.36.112.110]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 18C915D9D7; Mon, 18 Jan 2021 20:14:19 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella via Libc-help Subject: Re: Glibc 2.31 - time64 with 64-bit kernel and 32-bit userland References: <5FDBA7C2-79E2-4B21-98EF-800694DEB500@technology.de> Date: Mon, 18 Jan 2021 21:14:15 +0100 In-Reply-To: (Adhemerval Zanella via Libc-help's message of "Mon, 18 Jan 2021 16:31:24 -0300") Message-ID: <87sg6yknoo.fsf@oldenburg.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 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.6 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, 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-help@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-help mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Jan 2021 20:14:26 -0000 * Adhemerval Zanella via Libc-help: > This is the expected behavior, running this small example: > > -- > #include > > int main (int argc, char *argv[]) > { > clock_gettime (CLOCK_REALTIME, &((struct timespec) {})); > clock_gettime (CLOCK_BOOTTIME, &((struct timespec) {})); > return 0; > } > -- > > On a aarch64 kernel without 64-bit compat time_t support (4.12.13), > this is the generated syscalls: > > -- > clock_gettime64(CLOCK_REALTIME, 0xfffebb58) = -1 ENOSYS (Function not implemented) > clock_gettime(CLOCK_REALTIME, {tv_sec=1610997887, tv_nsec=516302599}) = 0 > clock_gettime(CLOCK_BOOTTIME, {tv_sec=2750059, tv_nsec=271773400}) = 0 > -- > > The catch here the 64-bit kernel when running 32-bit userland will > use compat entrypoints to provide the expected kernel ABI. For kernel > older than v5.1, it means that even if kernel is 64-bit and support > 64-bit time_t, the 32-bit syscall entrypoints won't have 64-bit time_t > support. Ugh. Is this for ILP32 support? Should we just undefined __NR_clock_gettime64 for 64-bit AArch64? 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