Efficient Fault Injection for Embedded Systems: As Fast as Possible but as Accurate as Necessary

When used for safety-critical applications, embedded systems must behave safely at all times - even in the presence of random hardware faults. To ensure this, fault effect simulation by simulation-based fault injection is an integral part of embedded system development. The high complexity of embedded systems results in low simulation performance if all details of the system are simulated. Not simulating all details, i.e. increasing the simulation abstraction level, speeds up fault injection but can result in less accuracy in predicting the fault impacts on the system behavior. To achieve high accuracy and high simulation performance at the same time, we avoid simulation of details unrelated to the injected fault. For this, we divide the set of faults that can occur in an embedded system into three subsets. For each subset, we select the fault injection abstraction level of the embedded processor model that is as accurate as necessary but as fast as possible. The considered levels are host-compiled simulation, instruction set simulation and register transfer level simulation. For additional speed-up, the abstraction level can be switched during the fault injection simulation between register transfer and instruction set level. The fault set for host-compiled simulation can be reduced by static program analysis. Our results show that adapting the abstraction level to the fault set achieves high performance of the fault injection simulation.