From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 70422 invoked by alias); 28 Sep 2018 12:51:25 -0000 Mailing-List: contact gnu-gabi-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Post: List-Help: List-Subscribe: Sender: gnu-gabi-owner@sourceware.org Received: (qmail 54383 invoked by uid 89); 28 Sep 2018 12:51:20 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.100.1 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS autolearn=no version=3.3.2 spammy=Hx-languages-length:1097 X-Spam-Status: No, score=-0.9 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS autolearn=no version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on sourceware.org X-Spam-Level: X-Spam-User: qpsmtpd, 2 recipients X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 28 Sep 2018 12:51:19 +0000 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2D3A981DF7; Fri, 28 Sep 2018 12:51:18 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-116-66.ams2.redhat.com [10.36.116.66]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1BF8F26FBF; Fri, 28 Sep 2018 12:51:15 +0000 (UTC) From: Florian Weimer To: Michael Matz Cc: "H.J. Lu" , Szabolcs Nagy , Jan Beulich , Rich Felker , Binutils , gnu-gabi@sourceware.org Subject: Re: RFC: Add SHT_GNU_PHDRS References: <87tvmbv8hp.fsf@oldenburg.str.redhat.com> <5BAC7D6802000078001EC6D1@prv1-mh.provo.novell.com> <87pnwzuz8r.fsf@oldenburg.str.redhat.com> <20180927103539.GJ10209@port70.net> <87va6rqfg6.fsf@oldenburg.str.redhat.com> <87r2hfqes1.fsf@oldenburg.str.redhat.com> Date: Mon, 01 Jan 2018 00:00:00 -0000 In-Reply-To: (Michael Matz's message of "Fri, 28 Sep 2018 12:32:33 +0000 (UTC)") Message-ID: <87lg7llr99.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 28 Sep 2018 12:51:18 +0000 (UTC) X-IsSubscribed: yes X-SW-Source: 2018-q3/txt/msg00027.txt.bz2 * Michael Matz: > On Thu, 27 Sep 2018, Florian Weimer wrote: > >> I'm now under the impression that the bits that are PT_LOAD'ed all need >> to be covered by (allocated) sections. > > That is wrong. Szabolcs is reading too much into some careless wording of > the ELF text that simply tries to convey the idea that usually segments > contents are the result of some sections combined by the link editor. > Sections are purely optional in the execution view. > > This section hack isn't necessary at all for what we need. The link > editor merely needs to ensure that the program headers are part of some > loadable segment, either by placing it not at the start of the file > (though that would mean the ELF header isn't part of the loaded image, > which is desirable to have), or by creating such loadble segment if > necessary. > > No gABI extensions are needed. That would certainly be nice. Can we try to update the ELF specification to clarify this? That should give us additional feedback whether this reading of the specification is correct. Thanks, Florian