Blocking address space from all access(A53)?

[Joakim Tjernlund]

We have this space that cannot be touched at all. devs makes mistakes and do that anyway.
Is these anyway I can block access even from /dev/mem accesses ?

i tried with this but that didn't block /dev/mem 
	reserved-memory {
		#address-cells = <2>;
		#size-cells = <1>;
		ranges;
		blocked_space {
			no-map;
			reg = <0x0 0x70000000 0x100000>;
		};
	};
Maybe it should?

 Jocke