This adds support for the STACKLEAK gcc plugin to arm64 by implementing
stackleak_check_alloca(), based heavily on the x86 version, and adding the
two helpers used by the stackleak common code: current_top_of_stack() and
on_thread_stack(). The stack erasure calls are made at syscall returns.
Additionally, this disables the plugin in hypervisor and EFI stub code,
which are out of scope for the protection.
Acked-by: NAlexander Popov <alex.popov@linux.com>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NLaura Abbott <labbott@redhat.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>