Data memory-dependent prefetcher: Difference between revisions

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A '''data memory-dependent prefetcher''' ('''DMP''') is a [[Prefetching (computing)|memory prefetcher]] that looks at [[Cache (computing)|cache memory]] content for possible [[Pointer (computer programming)|pointer]] values, and prefetches the data at those locations into cache if it sees memory access patterns that suggest following those pointers would be useful.<ref name=":0">{{Cite web |date=2022-05-02 |title=Augury |url=http://www.prefetchers.info/ |access-date=2024-03-21 |website=www.prefetchers.info}}</ref><ref>{{Cite journal |last=Vicarte |first=Jose Rodrigo Sanchez |last2=Flanders |first2=Michael |last3=Paccagnella |first3=Riccardo |last4=Garrett-Grossman |first4=Grant |last5=Morrison |first5=Adam |last6=Fletcher |first6=Christopher W. |last7=Kohlbrenner |first7=David |date=2022-05 |title=Augury: Using Data Memory-Dependent Prefetchers to Leak Data at Rest |url=https://ieeexplore.ieee.org/document/9833570/ |publisher=IEEE |pages=1491–1505 |doi=10.1109/SP46214.2022.9833570 |isbn=978-1-6654-1316-9}}</ref>

DataAs of 2022, data prefetching iswas already a common feature in modern CPUs,<ref>{{Citation |last=Bakhshalipour |first=Mohammad |title=A Survey on Recent Hardware Data Prefetching Approaches with An Emphasis on Servers |date=2020-09-01 |url=http://arxiv.org/abs/2009.00715 |access-date=2024-03-21 |doi=10.48550/arXiv.2009.00715 |last2=Shakerinava |first2=Mehran |last3=Golshan |first3=Fatemeh |last4=Ansari |first4=Ali |last5=Lotfi-Karman |first5=Pejman |last6=Sarbazi-Azad |first6=Hamid}}</ref> but most prefetchers do not inspect the data within the cache for pointers, instead working by monitoring memory access patterns. DMPs take this one step further.

The DMP in Apple's [[Apple M1|M1]] computer architecture was demonstrated to be capable of being used as a [[memory side-channel]] in work first reported in 2024.<ref>{{Cite web |last=Goodin |first=Dan |date=2024-03-21 |title=Unpatchable vulnerability in Apple chip leaks secret encryption keys |url=https://arstechnica.com/security/2024/03/hackers-can-extract-secret-encryption-keys-from-apples-mac-chips/ |access-date=2024-03-21 |website=Ars Technica |language=en-us}}</ref> As of the time of its announcement, no practical attacks using the side-channel were yet known to exist.<ref name=":0" />