Calculate Hash of Memory Layout

Hello,
I am looking for a smart way to calculate a Hash or something simular of the whole memory of the normal world. Does anyone know if the memory of normal world is accessible from secure world so I can store the programm securely there and how can I do this ? If anybody had some simular issues in the past or any ideas that might help me I would be really glad if you share this with me.

Thanks in advance and best regards,
Lukas