On Wed, Oct 13, 2021 at 05:22:43PM +0200, Ard Biesheuvel wrote:

> +config UNWIND_PATCH_PAC_INTO_SCS
> +	def_bool y
> +	depends on CC_IS_GCC && SHADOW_CALL_STACK
> +	select UNWIND_TABLES
> +	select ARM64_PTR_AUTH_KERNEL
> +

This needs a dependency on the GCC relevant toolchain features for
pointer auth doesn't it?  Or just make it depend on rather than select
pointer auth.