Presentation
PRAC-Auto: A Flexible and Efficient Framework for PRAC-Based Rowhammer Mitigation
DescriptionRowHammer (RH) remains a leading security threat in modern DRAM. Industry has standardized Per-Row Activation Counting (PRAC) for monitoring and Alert Back-Off (ABO) for mitigation, but ABO's pulse-only ALERT_n exposes little about which rows are at risk or how far recovery has progressed. Lacking actionable state, memory controllers fall back to coarse, pessimistic mitigation producing substantial performance loss. This paper presents PRAC-Auto, a practical, pin-compatible replacement for ABO that enables accurate, flexible, and efficient in-DRAM RH mitigation in PRAC-based systems. PRAC-Auto converts the standard ALERT_n into a lightweight handshake and introduces a subarray-status register read command, allowing the controller to discover which subarrays are affected and to track mitigation progress. With this finer-grained, progress-aware visibility, the controller continues serving requests to unaffected subarrays while the device autonomously refreshes only the vulnerable regions. Moreover, the autonomous mitigation can be extended or reduced via the handshake to reflect new traffic, improving security against adaptive performance attacks. Our evaluation demonstrates that PRAC-Auto nearly eliminates RH-mitigation performance overhead while providing robust protection.
Event Type
Work in Progress
TimeMonday, July 276:42pm - 6:43pm PDT
LocationExhibit Hall