On the integration and hardening of Software Test Libraries in Real-Time Operating Systems

The performance and complexity of Automotive System-on-Chip (SoC) have dramatically risen in the last decade thanks to technology scaling and moved to multicore capabilities. As a matter of fact, user requirements and the scenario complex-ity handled by devices are dramatically growing. Therefore, bare-metal safety-critical applications have shifted to a new application paradigm on top of Real-Time Operating Systems (RTOS). Safety standards require runtime self-check procedures the CPU executes from time to time. Such self-test procedures have strict requirements on their execution time and memory foot-print. The aforementioned self-test processes are also known as Software-Based Self Test encapsulated in Software Test Libraries. Following the shift to applications written on top of an RTOS, Software Test Libraries must also be integrated. This paper investigates possible software architectures when integrating Software Test Libraries in RTOSes with their pros e cons. Afterward, some hardening mechanisms are provided to overcome eventual problems in case permanent or transient faults arise. In order to simulate critical conditions, fault injections are performed via debugger in the Software Test Library to investigate their behavior and how they affect the system. Previously developed Software Test Library is integrated into a commercial RTOS called Micrium C OS-III. The fault injection campaign is performed on a real automotive System-on-Chip belonging to the SPC58 family from ST Microelectronics.