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Re: [RFC] [MIPS] Enable non-executable PT_GNU_STACK support v2
- From: "Maciej W. Rozycki" <macro at imgtec dot com>
- To: Aaro Koskinen <aaro dot koskinen at iki dot fi>
- Cc: <binutils at sourceware dot org>, Faraz Shahbazker <faraz dot shahbazker at imgtec dot com>, Joseph Myers <joseph at codesourcery dot com>, "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>, Aurelien Jarno <aurelien at aurel32 dot net>
- Date: Thu, 22 Dec 2016 00:52:41 +0000
- Subject: Re: [RFC] [MIPS] Enable non-executable PT_GNU_STACK support v2
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- References: <56A15768.20005@imgtec.com> <56A157AF.8080504@imgtec.com> <alpine.DEB.2.10.1601212215030.24424@digraph.polyomino.org.uk> <56A6BF93.5010401@imgtec.com> <56B4EC43.7040000@imgtec.com> <20160811210118.GA5342@aurel32.net> <20161222003609.3fdfjx6at2f5ffuv@raspberrypi-2.musicnaut.iki.fi>
Hi,
On Thu, 22 Dec 2016, Aaro Koskinen wrote:
> On Thu, Aug 11, 2016 at 11:01:18PM +0200, Aurelien Jarno wrote:
> > On 2016-02-05 10:38, Faraz Shahbazker wrote:
> > > Bump!
> > >
> > > Related patches for review:
> > > * binutils: https://sourceware.org/ml/libc-alpha/2016-01/msg00567.html
> > > * gcc : https://gcc.gnu.org/ml/gcc-patches/2016-02/msg00444.html
> > >
> >
> > It seems that the patches are present in the 2.27 binutils release,
> > while they are not yet ready on the glibc side (I guess still waiting
> > on the IFUNC patches).
> >
> > This means that building binaries with -Wl,-z,noexecstack set the ABI
> > version to 5 and we then have no way to execute them. Some configure
> > scripts probe for the availability of this option and enable it
> > automatically.
>
> Would it be possible to revert (or provide option to disable) these
> changes in binutils 2.28?
Making PT_GNU_STACK executables stop working with legacy glibc which
does not support the feature required is IIUC the whole point of the
binutils change, so it serves its purpose AFAICT. I can revert the
change, but before I do it can someone please tell me why can't MIPS
support for PT_GNU_STACK be simply pushed to glibc instead? And what's
the relevance of the IFUNC feature here (which will now use ABI version
6, the next available one) -- is there a functional dependency between
the glibc side of these two features?
Maciej