Hybrid fault detection technique: A case study on Virtex-II Pro's PowerPC 405

Hardening processor-based systems against transient faults requires new techniques able to combine high fault detection capabilities with the usual design requirements, e.g., reduced design-time, low area overhead, reduced (or null) accessibility to processor internal hardware. This paper proposes the adoption of a hybrid approach, which combines ideas from previous techniques based on software transformations with the introduction of an Infrastructure IP with reduced memory and performance overheads, to harden system based on the PowerPC 405 core available in Virtex-II Pro FPGAs. The proposed approach targets faults affecting the memory elements storing both the code and the data, independently of their location (inside or outside the processor). Extensive experimental results including comparisons with previous approaches are reported, which allow practically evaluating the characteristics of the method in terms of fault detection capabilities and area, memory and performance overheads.