From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 61937 invoked by alias); 15 May 2019 16:07:13 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 61929 invoked by uid 89); 15 May 2019 16:07:13 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-0.3 required=5.0 tests=AWL,BAYES_00,RDNS_DYNAMIC,TVD_RCVD_IP autolearn=no version=3.3.1 spammy=HX-Languages-Length:1981 X-HELO: brightrain.aerifal.cx Received: from 216-12-86-13.cv.mvl.ntelos.net (HELO brightrain.aerifal.cx) (216.12.86.13) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 15 May 2019 16:07:12 +0000 Received: from dalias by brightrain.aerifal.cx with local (Exim 3.15 #2) id 1hQwQY-0003s1-00; Wed, 15 May 2019 16:06:46 +0000 Date: Wed, 15 May 2019 16:07:00 -0000 From: Rich Felker To: Szabolcs Nagy Cc: Christophe Lyon , nd , Christophe Lyon , "gcc-patches@gcc.gnu.org" Subject: Re: [ARM/FDPIC v5 03/21] [ARM] FDPIC: Force FDPIC related options unless -mno-fdpic is provided Message-ID: <20190515160646.GW23599@brightrain.aerifal.cx> References: <20190515124006.25840-1-christophe.lyon@st.com> <20190515124006.25840-4-christophe.lyon@st.com> <67018f7b-f120-b33f-886f-c081a9ee1061@arm.com> <20190515143653.GT23599@brightrain.aerifal.cx> <20190515153718.GV23599@brightrain.aerifal.cx> <2d337959-2238-eb8d-012b-9f46e64728f8@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2d337959-2238-eb8d-012b-9f46e64728f8@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes X-SW-Source: 2019-05/txt/msg00868.txt.bz2 On Wed, May 15, 2019 at 03:59:39PM +0000, Szabolcs Nagy wrote: > On 15/05/2019 16:37, Rich Felker wrote: > > On Wed, May 15, 2019 at 05:12:11PM +0200, Christophe Lyon wrote: > >> On Wed, 15 May 2019 at 16:37, Rich Felker wrote: > >>> On Wed, May 15, 2019 at 01:55:30PM +0000, Szabolcs Nagy wrote: > >>>> can support both normal elf and fdpic elf so you can test/use > >>>> an fdpic toolchain on a system with mmu, but this requires > >>>> different dynamic linker name ..otherwise one has to run > >>>> executables in a chroot or separate mount namespace to change > >>>> the dynamic linker) > >>> > >>> Indeed, it's a bad idea to make them clash. > >>> > >> > >> Not sure to understand your point: indeed FDPIC binaries work > >> on a system with mmu, provided you have the right dynamic > >> linker in the right place, as well as the needed runtime libs (libc, etc....) > >> > >> Do you want me to change anything here? > > > > I think the concern is that if the PT_INTERP name is the same for > > binaries with different ABIs, you wouldn't be able to have both > > present in the same root fs, and this would make it more of a pain to > > debug fdpic binaries on a full (with-mmu) host. > > > > musl always uses a different PT_INTERP name for each ABI combination, > > so I guess the question is whether uclibc or whatever other libc > > you're intending people to use would also want to do this. > > glibc uses different names now for new abis, so i was expecting > some *_DYNAMIC_LINKER update, but it seems uclibc always uses > the same fixed name > > /lib/ld-uClibc.so.0 > > i guess it makes sense for them since iirc uclibc can change > its runtime abi based on lot of build time config so having > different name for each abi variant may be impractical. Yes, this "feature" of uclibc was was of the key motivations behind the creation of musl... :-) Rich