RFC: Add --enable-static-pie to build static executables as PIE

[Alan Modra]

On Mon, Jul 17, 2017 at 03:57:47PM -0700, H.J. Lu wrote:
> On Mon, Jul 17, 2017 at 3:29 PM, Rich Felker <dalias@libc.org> wrote:
> > On Mon, Jul 17, 2017 at 08:58:22AM -0700, H.J. Lu wrote:
> >> Hi,
> >>
> >> Are there any interests for --enable-static-pie, which builds static
> >> executables as PIE?
> >
> > Can you clarify what you're asking about? Is this asking if glibc is
> > interested in providing the runtime support (crt variant) for gcc to
> > be able to produce static PIE executables using glibc? I'm unclear on
> > whose configure script would need --enable-static-pie.
> >
> 
> --enable-static-pie will be a configure option to glibc:
> 
> 1. Build libc.a with -fPIE.
> 2. Update pointers in static PIE.
> 3. Apply IREL relocations for static PIE.
> 4 ....

Explain first exactly what you mean by a "static PIE".

- Will it be ET_EXEC or ET_DYN?
- What practical benefit do you get with a "static PIE"?
- What linker and kernel changes will be needed?

-- 
Alan Modra
Australia Development Lab, IBM