Micron Technology Incorporated

Cagdas Dirik

Robert Michael Walker

Edmund Gieske

Sujeet V Ayyapureddi

Ameen D Akel

Yang Lu

Elliott Clifford Cooper-Balis

Amitava Majumdar

Laurent Isenegger

Danilo Caraccio

Markus H Geiger

Elliott C Cooper-balis

Horia Cristian Simionescu

Patrick A La Fratta

Paul Roger Stonelake

Chung Kuang Chin

Narasimhulu Dharanikumar Kotte

Niccolo Izzo

Niccolo′ Izzo

An apparatus can include a number of memory devices and a controller coupled to one or more of the number of memory devices. The controller can include row hammer detection circuitry configured to receive signaling indicative of a row activation command having a row address, increment a row counter corresponding to the row address stored in a stored in a data structure in a register or storage device, determine whether the incremented row counter is greater than a row hammer threshold, and issue a row hammer mitigation command to mitigate row hammer.

Row hammer mitigation using hierarchical detectors

An access tracker configured to receive a request to access a page, determine whether a page identification (ID) associated with the page is in the access tracker, increment an access count of the page in response to determining the page ID is in the access tracker, sort a number of page IDs based on an access count of each page ID, and determine whether a different page is hot or cold in response to sorting the number of page IDs.

Access tracking in memory

An energy-efficient and area-efficient, mitigation of errors in a memory media device that are caused by row hammer attacks and the like is described. The detection of errors is deterministically performed while maintaining, in an SRAM, a number of row access counters that is smaller than the total number of rows protected in the memory media device. The reduction of the number of required counters is achieved by aliasing a plurality of rows that are being protected to each counter. The mitigation may be implemented on a per-bank basis, per-channel basis or per-memory media device basis. The memory media device may be DRAM.

Aliased row hammer detector

Exemplary methods, apparatuses, and systems include detecting an operation to write dirty data to a cache. The cache is divided into a plurality of channels. In response to the operation, the dirty data is written to a first cache line in the cache, the first cache line being accessed via a first channel. Additionally, a redundant copy of the dirty data is written to a second cache line in the cache. The second cache line serves as a redundant write buffer and is accessed via a second channel, the first and second channels differing from one another. A metadata entry for the second cache line is updated to reference a location of the dirty data in the first cache line.

Dynamically sized redundant write buffer with sector-based tracking

Systems and methods for finite time counting period counting of infinite data streams is presented. In particular example systems and methods enable counting row accesses to a memory media device over predetermined time intervals in order to deterministically detect row hammer attacks on the memory media device. Example embodiments use two identical tables that are reset at times offset in relation to each other in a ping-pong manner in order to ensure that there exists no false negative detections. The counting techniques described in this disclosure can be used in various types of row hammer mitigation techniques and can be implemented in content addressable memory or another type of memory. The mitigation may be implemented on a per-bank basis, per-channel basis or per-memory media device basis. The memory media device may be a dynamic random access memory type device.

Finite time counting period counting of infinite data streams

Systems and methods for area-efficient mitigation of errors that are caused by row hammer attacks and the like in a memory media device are described. The counters for counting row accesses are maintained in a content addressable memory (CAM) the provides fast access times. The detection of errors is deterministically performed while maintaining a number of row access counters that is smaller than the total number of rows protected in the memory media device. The circuitry for the detection and mitigation may be in the memory media device or in a memory controller to which the memory media device attaches. The memory media device may be dynamic random access memory (DRAM).

Area-optimized row hammer mitigation

A system comprising a row hammer mitigation circuitry and a cache memory that collaborate to mitigate row hammer attacks on a memory media device is described. The cache memory biases cache policy based on row access count information maintained by the row hammer mitigation circuit. The row hammer mitigation circuitry may be implemented in a memory controller. The memory media device may be DRAM. Corresponding methods are also described.

Cache-assisted row hammer mitigation

Systems, methods, and apparatus for memory device security and row hammer mitigation are described. A control mechanism may be implemented in a front-end and/or a back-end of a memory sub-system to refresh rows of the memory. A row activation command having a row address at control circuitry of a memory sub-system and incrementing a first count of a row counter corresponding to the row address stored in a content addressable memory (CAM) of the memory sub-system may be received. Control circuitry may determine whether the first count is greater than a row hammer threshold (RHT) minus a second count of a CAM decrease counter (CDC); the second count may be incremented each time the CAM is full. A refresh command to the row address may be issued when a determination is made that the first count is greater than the RHT minus the second count.

Memory device security and row hammer mitigation

A cache memory having a memory media device row activation-biased caching policy is described. The cache policies that are biased based on row activation counts include at least one of a cache line eviction policy which determines which cache lines are the most evictable from the cache memory, and cache line storage policy which determined which row data is allocated cache lines for storage. A memory controller including a row activation-biased cache memory is also described. The memory media device may be DRAM.

Memory media row activation-biased caching

A method includes receiving, at a direct memory access (DMA) controller of a memory device, a first command from a first cache controller coupled to the memory device to prefetch first data from the memory device and sending the prefetched first data, in response to receiving the first command, to a second cache controller coupled to the memory device. The method can further include receiving a second command from a second cache controller coupled to the memory device to prefetch second data from the memory device, and sending the prefetched second data, in response to receiving the second command, to a third cache controller coupled to the memory device.

Interleaved cache prefetching

The present disclosure includes apparatuses and methods related to a memory system with cache line data. An example apparatus can store data in a number of cache lines in the cache, wherein each of the number of lines includes a number of chunks of data that are individually accessible.

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Indianola, WA, United States of America

Cagdas Dirik