[PATCH] powerpc64le: ROP changes for clone/clone3

[Florian Weimer]

* Sachin Monga:

> Store/Retrieve ROP pointer in Red zone
>
> Signed-off-by: Sachin Monga <smonga@linux.ibm.com>

Could you spill lr to a nonvolatile register instead?  If I read
Documentation/powerpc/syscall64-abi.rst along with the ELF psABI
correctly, r14 to r31 should be available.  If you spill to a
register, no ROP protection will be needed.