A Novel Efficient Crash Consistency Solution Enabling Rollback Recovery for Secure NVM in Low-Power Energy Harvesting Systems

Energy Harvesting Systems (EHSs) frequently suffer power failures and are particularly deployed in remote and open environments where physical access attacks on Non-volatile Memories (NVMs) are practical. However, prior crash consistency solutions for secure NVM were designed only for conventional power-rich systems with the assumption that enough power is steadily supplied. Moreover, the prior solutions rely on roll-forward recovery and cause a significant performance overhead in low-power EHSs. To achieve a low-cost and high-performance crash-consistent secure NVM working on low-power EHSs, this paper presents Milestone, the first efficient crash consistency solution that introduces a novel hybrid checkpoint mechanism to enable a rollback recovery for secure NVM working in frequent power failures.The hybrid checkpointing atomically (1) undo-logs data updates from program writes and (2) redo-logs the updates of security metadata associated with the data updates when an adaptive hardware timer expires. In particular, Milestone discovers an optimized eager update method for the security metadata that can be performed in parallel with the program writes to NVM by leveraging the rollback recovery. Our experimental results demonstrate that Milestone significantly outperforms the state-of-the-art roll-forward recovery-based solution for secure NVM running on low-power EHSs, achieving up to a 1.87x speedup, on average.