From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from hera.aquilenet.fr (hera.aquilenet.fr [185.233.100.1]) by sourceware.org (Postfix) with ESMTPS id C8FEC3857805 for ; Tue, 6 Apr 2021 18:03:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org C8FEC3857805 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=ens-lyon.org Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=samuel.thibault@ens-lyon.org Received: from localhost (localhost [127.0.0.1]) by hera.aquilenet.fr (Postfix) with ESMTP id 83DDA5D8; Tue, 6 Apr 2021 20:03:40 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at aquilenet.fr Received: from hera.aquilenet.fr ([127.0.0.1]) by localhost (hera.aquilenet.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id julKYVvHJXkZ; Tue, 6 Apr 2021 20:03:39 +0200 (CEST) Received: from begin (unknown [IPv6:2a01:cb19:956:1b00:de41:a9ff:fe47:ec49]) by hera.aquilenet.fr (Postfix) with ESMTPSA id A9A77B1; Tue, 6 Apr 2021 20:03:39 +0200 (CEST) Received: from samy by begin with local (Exim 4.94) (envelope-from ) id 1lTq38-00FpPe-HS; Tue, 06 Apr 2021 20:03:38 +0200 Date: Tue, 6 Apr 2021 20:03:38 +0200 From: Samuel Thibault To: Adhemerval Zanella Cc: libc-alpha@sourceware.org, Szabolcs Nagy , rrh.henry@gmail.com Subject: Re: RFC: Remove --disable-hidden-plt Message-ID: <20210406180338.wh2vwyqqsro7v3d5@begin> References: <28ab0b62-2b14-4fd2-b333-abb1d91fa714@linaro.org> <20210406171833.24b5vr4j2b762knb@begin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: I am not organized User-Agent: NeoMutt/20170609 (1.8.3) X-Spamd-Bar: -- Authentication-Results: hera.aquilenet.fr X-Rspamd-Server: hera X-Rspamd-Queue-Id: 83DDA5D8 X-Spamd-Result: default: False [-2.50 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; HAS_ORG_HEADER(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; MID_RHS_NOT_FQDN(0.50)[]; BAYES_HAM(-3.00)[100.00%] X-Spam-Status: No, score=-5.7 required=5.0 tests=BAYES_00, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_NEUTRAL, TXREP autolearn=no 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: Tue, 06 Apr 2021 18:03:43 -0000 Adhemerval Zanella, le mar. 06 avril 2021 14:39:27 -0300, a ecrit: > On 06/04/2021 14:18, Samuel Thibault wrote: > > Adhemerval Zanella via Libc-alpha, le mar. 06 avril 2021 14:12:41 -0300, a ecrit: > >> On 03/04/2021 14:41, H.J. Lu via Libc-alpha wrote: > >> However it seems it will still need to support it internally for > >> Hurd > > > > Yes, some symbols in ld.so (most of sysdeps/mach/hurd/dl-sysdep.c) > > *need* to be interposed by the loaded libc.so, because the > > implementation in ld.so is to be used only at bootstrap of the program, > > and then overriden by the real full-fledged implementation. > > Are these the only ones required to Hurd? Yes. Previously we were using the NO_HIDDEN hammer, but: > I wonder if would be simple to instead of have the bit NO_HIDDEN > hammer, to create a different hidden_def/hidden_proto to be used on > the required symbols (where default version would map to use non-PLT > call and Hurd could just reimplement it). That was already roughly done in 3d1870fa3301c5cd00d5fdab0014c4e22b71fef2 where we made all rtld_hidden_proto respect NO_RTLD_HIDDEN. I didn't specifically mark the exactly required functions, but the localplt check exceptions in sysdeps/mach/hurd/i386/localplt.data is already exactly the list of needed PLTs, so I don't think it's worth the extra maintenance complexity of special-casing in the headers for everyone in addition to the rtld implementation in dl-sysdep.c. Samuel