QUALCOMM Incorporated
ON-DIE VOLTAGE-FREQUENCY SECURITY MONITOR

Abstract:

A method to prevent a malicious attack on CPU subsystem (CPUSS) hardware is described. The method includes auto-calibrating tunable delay elements of a dynamic variation monitor (DVM) using an auto-calibration value computed in response to each detected change of a clock frequency (Fclk)/supply voltage (Vdd) of the CPUSS hardware. The method also includes comparing the auto-calibration value with a threshold reference calibration value to determine whether the malicious attack is detected. The method further includes forcing a safe clock frequency (Fclk)/safe supply voltage (Vdd) to the CPUSS hardware when the malicious attack is detected.