[PATCH 3/7] Add GLIBC_ABI_DT_RELR for DT_RELR support

[H.J. Lu]

On Fri, Feb 4, 2022 at 3:58 PM Joseph Myers <joseph@codesourcery.com> wrote:
>
> On Fri, 4 Feb 2022, H.J. Lu via Libc-alpha wrote:
>
> > On Fri, Feb 4, 2022 at 1:01 PM Joseph Myers <joseph@codesourcery.com> wrote:
> > >
> > > On Fri, 4 Feb 2022, H.J. Lu via Libc-alpha wrote:
> > >
> > > > Good point.  How about "enable DT_RELR only if SUPPORT_DT_RELR is
> > > > defined?  Currently, only x86 defines SUPPORT_DT_RELR.
> > >
> > > My preference would be:
> > >
> > > 1. Support user executables and shared libraries with RELR relocations
> > > across all platforms, unconditionally.
> >
> > RELR is kind of like static PIE.  Not all architectures support it.
>
> My understanding is that analogy only applies to the static linker, not to
> glibc itself - that the static linker needs architecture-specific code,
> but glibc doesn't (as evidenced by the lack of any architecture-specific
> non-configure changes in this patch series).
>
> > RELR should be enabled only if there is a linker which supports
> > -z pack-relative-relocs.
>
> (a) That should only apply to "enabled" in the sense of "glibc itself uses
> RELR relocations", not "glibc supports loading executables and shared
> libraries with such relocations".
>
> (b) The configure test for that should be architecture-independent, with
> no architecture-specific configure changes needed at all.
>

Fixed in the v2 patch.

-- 
H.J.