A data memory-dependent prefetcher (DMP) is a
cache prefetcher that looks at
cache memory content for possible
pointer
Pointer may refer to:
Places
* Pointer, Kentucky
* Pointers, New Jersey
* Pointers Airport, Wasco County, Oregon, United States
* The Pointers, a pair of rocks off Antarctica
People with the name
* Pointer (surname), a surname (including a list ...
values, and prefetches the data at those locations into cache if it sees memory access patterns that suggest following those pointers would be useful.
As of 2022, data prefetching was already a common feature in CPUs, but most prefetchers do not inspect the data within the cache for pointers, instead working by monitoring memory access patterns. Data memory-dependent prefetchers take this one step further.
The DMP in Apple's
M1 computer architecture was demonstrated to be capable of being used as a
memory side-channel in an attack published in early 2024. At that time its authors did not know of any practical way to exploit it. The DMP was subsequently discovered to be even more opportunistic than previously thought, and has now been demonstrated to be able to be used to effectively attack a variety of cryptographic algorithms in work called
GoFetch
GoFetch is a family of cryptographic attacks on recent Apple silicon CPUs that exploits the CPU's on-chip data memory-dependent prefetcher (DMP) to investigate the contents of memory. CPUs affected include the M1, M2, M3 and A14 series sys ...
by its authors.
processors also have DMP functionality (Intel use the term "Data Dependent Prefetcher") but Intel states that they have features to prevent their DMPs being used for side-channel attacks.
The authors of GoFetch state that they were unable to make their exploit work on Intel processors.
References
Digital circuits
Computer architecture
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