Containing timing-related certification cost in automotive systems deploying complex hardware

Abstract

Measurement-Based Probabilistic Timing Analysis (MBPTA) techniques simplify deriving tight and trustworthy WCET estimates for industrial-size programs running on complex processors. MBPTA poses some requirements on the timing behaviour of the hardware/software platform: execution times of end-to-end runs have to be independent and identically distributed (i.i.d.). Hardware and software solutions have been deployed to accomplish MBPTA requirements. The latter has achieved the i.i.d. properties running on some commercial off-the-shelf (COTS) processor designs. Unfortunately, software randomisation challenges functional verification needed for certification since it introduces indirections through pointers in the code. In this paper we propose a new approach to software randomisation able to contain its functional verification costs. Our approach performs software randomisation statically, as opposed to current dynamic approaches. We carefully review the requirements of the new approach and prove its feasibility.