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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 2B55C3854834 for ; Mon, 21 Jun 2021 12:57:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 2B55C3854834 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-503-3DswDup6N4iwSwAXpxwQcg-1; Mon, 21 Jun 2021 08:57:38 -0400 X-MC-Unique: 3DswDup6N4iwSwAXpxwQcg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 51315100CA9E; Mon, 21 Jun 2021 12:57:37 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-115-60.ams2.redhat.com [10.36.115.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 755A760871; Mon, 21 Jun 2021 12:57:36 +0000 (UTC) From: Florian Weimer To: "H.J. Lu" Cc: "H.J. Lu via Libc-alpha" Subject: Re: [PATCH 4/4] Update tests for protected data and function symbols References: <20210620233620.391576-1-hjl.tools@gmail.com> <20210620233620.391576-5-hjl.tools@gmail.com> <878s33n0q0.fsf@oldenburg.str.redhat.com> Date: Mon, 21 Jun 2021 14:57:34 +0200 In-Reply-To: (H. J. Lu's message of "Mon, 21 Jun 2021 05:54:58 -0700") Message-ID: <875yy7jry9.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, KAM_SHORT, 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-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, 21 Jun 2021 12:57:44 -0000 * H. J. Lu: > On Mon, Jun 21, 2021 at 12:19 AM Florian Weimer wrote: >> >> * H. J. Lu via Libc-alpha: >> >> > Protected data and function symbols don't work well without >> > -fsingle-global-definition: >> > >> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37611 >> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44166 >> > >> > 1. Compile tst-protected1[ab].c and tst-protected1mod[ab].c with >> > -fsingle-global-definition if possible so that GOT entries are used >> > for undefined data accesses. >> > 2. Add tests for protected function pointers. >> > 3. Build tst-prelink.c without single global definition to keepp COPY >> > relocation. >> >> I think these tests need to check that the statically linked bits from >> GCC have been built with -fsingle-global-definition. I don't think >> that's guaranteed even if GCC supports -fsingle-global-definition. >> >> I think this shows the limitation of the single bit of markup: the >> statically linked GCC bits are all hidden, so setting >> GNU_PROPERTY_1_NEEDED_SINGLE_GLOBAL_DEFINITION so is not correct as a >> marker to *require* a single global definition, but neither is not >> setting it because libgcc.a etc. should be *compatible* with >> GNU_PROPERTY_1_NEEDED_SINGLE_GLOBAL_DEFINITION. > > The output bit is ORed from all inputs. When one input object file doesn't > work with COPY relocation, the final output object is marked incompatible > with COPY relocation even if some inputs do work with COPY relocation. But for the main executable, it has to work the other way round. Thanks, Florian