TL-HLS: Methodology for Low Cost Hardware Trojan Security Aware Scheduling With Optimal Loop Unrolling Factor During High Level Synthesis

Security against hardware Trojan that is capable to change the computational output value is accomplished by employing dual modular redundant (DMR) schedule during high level synthesis (HLS). However, building a DMR for Trojan security is nontrivial and incurs extra delay and hardware. This paper proposes a novel HLS methodology for constraint driven low cost hardware Trojan secured DMR schedule design for loop-based control data flow graphs (CDFGs). Proposed approach simultaneously explores an optimal schedule and optimal loop unrolling factor (U) combination for a low cost Trojan security aware DMR schedule. As a specific example, proposed low cost Trojan secured HLS approach relies on particle swarm optimization algorithm to explore optimized Trojan secured schedule with optimal unrolling that provides security against specific Trojan (causing change in computational output) within user provided area and delay constraints. The novel contributions of this paper are, first an exploration of a low cost Trojan security aware HLS solution for loop-based CDFGs; second, proposed encoding scheme for representing design solution comprising candidate schedule resources, candidate loop unrolling factor and candidate vendor allocation information; third, a process for exploring the a low cost vendor assignment that provides Trojan security; finally, experimental results over the standard benchmark that indicates an average reduction in final cost of ~12% compared to recent approach.