Per-Channel Row Hammer Alert Signaling in Memory Devices
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Solution Overview
Problem
Existing memory devices struggle to effectively alert hosts to row hammer attacks, particularly in 3D memory devices like HBM, due to the large number of channels and the inefficiency of conventional alert signaling methods.
Innovation Solution
The implementation of overloaded per-channel alert signaling in memory devices, which utilizes existing pins and interfaces to transmit alert information during unused windows, allowing for per-channel or per-PC alert signaling without the need for additional pins or interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional alert signaling methods are used in 3D memory devices with multiple channels, then the device structure remains simple, but the ability to alert hosts to row hammer attacks on specific channels is insufficient
Solution Approach 1:
The alert signaling function is segmented by channel, with each channel having its own alert pin and independent alert logic. This allows the memory device to independently alert the host about row hammer attacks on specific channels without affecting other channels, resolving the contradiction between alert capability and structural complexity.
Solution Approach 2:
The existing per-channel data interface is made multi-functional by using it to transmit both data and alert information. The alert pin serves dual purposes: indicating channel availability and signaling row hammer attacks. This universal approach improves alert capability without adding dedicated alert signaling infrastructure.
2Measurement precision
If additional pins or interfaces are added for per-channel alert signaling, then the alert precision improves, but the device complexity and manufacturing cost increase
Solution Approach 1:
The existing per-channel data interface pins are made multi-functional to carry both data signals and alert signals. By reusing the same physical infrastructure for dual purposes, the patent achieves precise per-channel alert identification without adding new pins or interfaces, thus avoiding increased device complexity and manufacturing cost.
Solution Approach 2:
The memory device uses its own existing per-channel interface infrastructure to provide alert functionality. Rather than requiring external alert infrastructure or additional dedicated alert pins, the system serves its own alerting needs through intelligent reuse of existing resources, maintaining simplicity while achieving precision.
3Productivity
If a single shared alert pin is used across all channels, then the device complexity is reduced, but the productivity and response time are reduced because the host must suspend all channel operations
Solution Approach 1:
The alert signaling is segmented by channel, with each channel having independent alert capability. This allows the host to identify and suspend operations only on the specific channel experiencing a row hammer attack, while continuing normal operations on other channels. This segmentation maintains high productivity by avoiding unnecessary suspensions of healthy channels.
Solution Approach 2:
The alert system is made dynamic and adaptive to channel-specific conditions. Rather than a static global alert that affects all channels uniformly, the system dynamically generates channel-specific alerts that enable selective suspension. This dynamic approach optimizes productivity by maintaining operations on unaffected channels while responding to attacks on specific channels.
4Ease of manufacture
If per-channel alert signaling is implemented using existing pins, then the ease of manufacture is improved, but the reliability of alert transmission may be compromised due to signal interference
Solution Approach 1:
The alert information is transmitted periodically during unused windows of the per-channel interface. Rather than continuously monitoring or using dedicated alert lines, the system utilizes idle time periods in the existing data interface to transmit alert signals. This periodic transmission during unused windows avoids interference with active data operations while maintaining reliable alert delivery.
Solution Approach 2:
The unused interface windows serve as an intermediary medium for transmitting alert information. By using the idle temporal space in the existing data interface as a carrier for alert signals, the patent avoids direct signal interference between data and alert transmissions while still achieving reliable alert delivery through the same physical infrastructure.
Data Source
AI summary
Disclosed are methods, systems, and apparatuses for providing per-channel row hammer alerts, from a memory device to a host, without the use of a dedicated per-channel alert interface. When detecting a row hammer alert condition, the memory device may determine whether an existing interface (e.g., a severity interface used to transmit severity information) is available. The interface may be available outside of certain designated burst positions during a read burst. Once the interface is available, the memory device may transmit a row hammer alert indication to the host. The host may determine whether information received over the interface is associated with a row hammer alert or severity, depending on when the information was received (e.g., in what burst position during a read burst).