Software test libraries and real-time operating systems: A system integrator perspective

In safety-critical systems, functional safety (FuSA) standards require online testing capabilities, for example Software Test Libraries (STLs), which are flexible functional self-test procedures executed to verify the SoC functional behavior. However, the growing complexity of scenarios requires effective hardware management and orchestration achieved by Real-Time Operating Systems (RTOSs). The rising popularity of STLs as online testing techniques is flowing into the coexistence of RTOSs and STLs, raising concerns about how to effectively integrate those two software modules. This work proposes methodologies to correctly and effectively integrate STLs and RTOSs already developed from a system integrator perspective. It describes a portable library interface, called PTLIX, for correctly and effectively integrate STLs across different RTOSs. In addition, it describes analytical execution time and memory footprints requirements to effectively integrate the two software modules. In order to support the analytical requirements, different case studies are presented for STLs based on two different Instruction Set Architectures (RISC-V and PowerPC) integrated in different RTOSs, such as FreeRTOS, Micrium-C OS III and Zephyr.