TrustZone for Supervised Asymmetric Multiprocessing Systems

Many modern forms of asymmetric multiprocessing (AMP) architecture use hypervisors to increase software security by isolating the system software in virtual machines. However, efficient virtualisation depends on hardware support that is not available across all products. Within modern ARM architectures, the aforementioned software isolation can also be implemented using ARM TrustZone technology. This paper presents a TrustZone-based AMP architecture (TZ-AMP) that can consolidate multiple system software environments securely on devices that lack hardware virtualisation support. We evaluate our prototype on the ARMv7-A architecture, and demonstrate TrustZone-based context-switching performance in the order of microseconds, confirming that TZ-AMP maintains high performance while also achieving hardware-backed software security.