Multi-Context Execution on a RISC-V Core for Mixed-Criticality Systems

Mixed-criticality systems integrating software modules with varying levels of criticality require robust isolation to ensure safety and dependability. High-end and mid-end architectures achieve this through strict time and space partitioning supported by multiple privilege levels and memory management units. However, low-end processors, limited to two privilege levels, face challenges in implementing efficient time and space partitioning without compromising system composability. This paper introduces a novel multi-context environment for low-end RISC-V processors, leveraging a lightweight hardware extension and enabling efficient time and space partitioning. The proposed solution not only ensures robust isolation and system composability but also provides flexibility to balance hardware and software overhead, advancing the state of the art in the dependability for resource-constrained systems.