Pass --enable-standard-branch-protection. This is an aarch64-specific
option (currently) which does nothing on other targets. On aarch64 this
generates code uses BTI/PAC instructions to mitigate Return Orientated
Programming attacks. This approach is backwards compatible and the code
size/performance impact is typically negliable.
More details can be found at
https://events.static.linuxfound.org/sites/events/files/slides/slides_23.pdf
Signed-off-by: Ross Burton <ross.burton@arm.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
