Nordic Semiconductor ASA
MEMORY-ACCESS CONTROL

Abstract:

An electronic device comprises a processor, a memory, a memory controller for controlling access to the memory, a hardware security module, and a bus system, to which the processor, the memory controller, and the hardware security module are connected. The hardware security module uses its connection to the bus system to detect requests on the bus system that are sent by the processor. The hardware security module has a secure state and a non-secure state. When in the secure state, the hardware security module adds a secure-state signal to requests sent by the processor over the bus system. The memory controller determines whether memory-access requests include the secure-state signal, and denies access to a secure region of the memory in response to receiving memory-access requests that do not include the secure-state signal.