RFC: Shadow Stack support in glibc

[H.J. Lu]

On Fri, Jun 9, 2017 at 2:05 AM, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>
> fixing setjmp/longjmp is non-trivial since jmpbuf size is abi,
> it may be possible to do without saving ssp into jmpbuf though.
>

Shadow stack is enabled at run-time only if all sources are compiled
with shadow stack enabled compiler against shadow stack enabled
glibc.  setjmp/longjmp are implemented with IFUNC, which uses
the old setjmp/longjmp if shadow stack is off and uses the new
setjmp/longjmp if shadow stack is on.

-- 
H.J.