From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15589 invoked by alias); 20 Feb 2020 09:37:38 -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 15498 invoked by uid 89); 20 Feb 2020 09:37:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.100.3 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-6.2 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.1 spammy=H*i:sk:TRX53E-, H*MI:sk:TRX53E-, H*f:sk:TRX53E-, H*MI:sk:2e29243 X-Spam-Status: No, score=-6.2 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on sourceware.org X-Spam-Level: X-Spam-User: qpsmtpd, 2 recipients X-HELO: gnu.wildebeest.org Received: from wildebeest.demon.nl (HELO gnu.wildebeest.org) (212.238.236.112) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 20 Feb 2020 09:37:35 +0000 Received: from tarox.wildebeest.org (tarox.wildebeest.org [172.31.17.39]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by gnu.wildebeest.org (Postfix) with ESMTPSA id BCD43300D925; Thu, 20 Feb 2020 10:37:33 +0100 (CET) Received: by tarox.wildebeest.org (Postfix, from userid 1000) id 71406401ED8C; Thu, 20 Feb 2020 10:37:33 +0100 (CET) Message-ID: Subject: Re: binutils ld and new PT_GNU_PROPERTY segment From: Mark Wielaard To: "H.J. Lu" Cc: Fangrui Song , Cary Coutant , "Zhang, Annita" , "Liu, Hongtao" , gnu-gabi , Binutils Date: Wed, 01 Jan 2020 00:00:00 -0000 In-Reply-To: References: <20200219023120.gvr4ajolbjbqcfix@google.com> <6bf04476b559f11965b4474b500156e26949ffc2.camel@klomp.org> <20200219182701.vrtzwhgtpelmpaub@google.com> <2e29243995903cf2d52975543675f2b92fa1e201.camel@klomp.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Evolution 3.28.5 (3.28.5-5.el7) Mime-Version: 1.0 X-Spam-Flag: NO X-SW-Source: 2020-q1/txt/msg00016.txt Hi, On Wed, 2020-02-19 at 14:17 -0800, H.J. Lu wrote: > On Wed, Feb 19, 2020 at 1:46 PM Mark Wielaard wrote: > > This code isn't in the kernel yet. So either it gets changed to use the > > existing scheme with gnu property notes found through PT_NOTE to work > > with existing binaries. Then there is no need for PT_GNU_PROPERTY > > headers. > >=20 > > Or some future kernel will start using PT_GNU_PROPERTY headers to find > > the gnu property notes. But that means it won't work with existing > > binaries that do not have that header. So there is no backwards > > compatibility anyway and we can define SHT_GNU_PROPERTY like above. > >=20 > > So this actually seems the perfect time to make this decision. >=20 > Binaries with .note.gnu.property section have been put into many > OS releases. We must support them. OK. Then it is option 1. The kernel will need to support PT_NOTE for parsing the properties, since such older binaries won't have a PT_GNU_PROPERTY program header. Then we can simply get rid of PT_GNU_PROPERTY since nobody uses it and all information is already available through the PT_NOTE segment. Cheers, Mark