Memory Device Attack Row Selector for Rowhammer Mitigation
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Solution Overview
Problem
As the density of memory cells in memory devices increases, the charge of memory cells in adjacent rows can be affected by voltage distribution, leading to issues like rowhammer, where intensive access to one row can alter data in adjacent rows, necessitating effective refresh operations.
Innovation Solution
A memory device with an attack row selector, an attack row register, and a victim row determiner is implemented. The attack row selector generates an update signal based on an accumulation value of activation signals, the attack row register determines the attack row address, and the victim row determiner identifies a victim row address for refresh, thereby addressing rowhammer effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cell density is increased, then storage capacity is improved, but voltage distribution effects on adjacent rows worsen, causing rowhammer attacks
Solution Approach 1:
The patent applies preliminary action by performing refresh operations on victim rows before rowhammer attacks can occur. The system monitors activation counts of rows and proactively identifies rows that are likely to be affected by voltage distribution effects, then performs refresh operations on these victim rows in advance. This preventive approach counteracts the harmful voltage distribution effects caused by high memory cell density without requiring a reduction in density.
2Reliability
If refresh operations are performed on all rows, then data integrity is improved, but operational complexity and time consumption increase
Solution Approach 1:
The patent applies local quality by performing refresh operations selectively only on victim rows that are likely to be affected by rowhammer attacks, rather than refreshing all rows uniformly. The system determines which rows are victims based on their activation patterns and voltage distribution characteristics, then applies refresh operations only to these specific rows. This targeted approach maintains data integrity for affected rows while reducing the overall complexity and time consumption of refresh operations compared to a comprehensive refresh of all rows.
3Productivity
If intensive access is performed on a row, then read/write performance is improved, but voltage effects on adjacent rows worsen, causing data changes
Solution Approach 1:
The patent applies feedback by continuously monitoring the activation counts of rows and using this information to determine which rows should be performed with intensive access and which are likely to be affected by voltage effects. The system uses feedback from activation pattern analysis to dynamically adjust refresh operations, ensuring that rows experiencing intensive access are properly managed while protecting adjacent rows from voltage-induced data changes. This feedback mechanism allows the system to maintain high read/write performance while mitigating harmful voltage effects.
Data Source
AI summary
A memory device may include an attack row selector configured to receive an activation signal at a first time point, and generate an update signal based on an accumulation value, an attack row register configured to receive an activation row address corresponding to the activation signal, and determine an attack row address based on the update signal and the activation row address, and a victim row determiner configured to determine a victim row address based on the attack row address. The accumulation value may be the number of activation signals received from a second time point before the first time point to the first time point.