Arm's SVE PCS and LD_AUDIT support?

[Carlos O'Donell]

Szabolcs,

One of the things I want to refactor is to move some of the LD_AUDIT
support up a level inside the dynamic loader and have it depend
less on the lazy-binding semantics.

I want only la_pltenter() and la_pltexit() to be affected by the
binding semantics, but today because lazy was the default, we aren't
there yet.

Florian and I were wondering if we couldn't implement the following:

- Leave PLT in place for SVE PCS but unused.

- Enable full save-restore in plt enter/exit conservatively for
  STO_AARCH64_VARIANT_PCS if LD_AUDIT is in use, possibly routing
  those symbols to a different _dl_profile_fixup_full_save?

Would that work? 

-- 
Cheers,
Carlos.