关键词: DRAM存储器, 行扰动, 概率刷新, 最近激活计数器

Abstract:

As DRAM memory scales down to smaller technology nodes, row hammering becomes a critical problem that not only degrades system reliability but also opens up security vulnerabilities. This paper proposes a new row-refresh hammering prevention solution, named Recent Activation Counter based Probabilistic Refresh（RACPR）, which exploits the recent activation information of victim rows. This paper first makes a key observation that a passive activation to victim rows has the same effect of preventing row hammering compared to a dedicated proactive refresh. This paper then proposes Recent Activation Counter（RAC） to track the timing information of activation per row. This paper optimizes the structure and operation of RAC so as to reduce its complexity and overheads. RACPR strategy provides robust row hammering protection at negligible performance overhead and 0.006% area cost. Experimental results show that the approach further reduces the number of proactive refresh by 75% on average, and provides better average performance compared to previous probabilistic approaches.

Key words: DRAM, row hammering, probabilistic refresh, recent activation counter