Sifive, Inc.

John Ingalls

Wesley Waylon Terpstra

Henry Cook

Josh Smith

Leigang Kou

Shubhendu Sekhar Mukherjee

Krste Asanovic

Andrew Waterman

Yann Loisel

Mohit Gopal Wani

Benoy Alexander

Systems and methods are disclosed for error management in a system on a chip with a securely partitioned memory space. For example, an integrated circuit (e.g., a processor) for executing instructions includes a world identifier checker circuitry configured to check memory requests for one or more memory mapped resources that are received via the bus that have been tagged with a world identifier to determine whether to allow or reject access based on the tagged world identifier; a world identifier checker circuitry configured to compare the tagged world identifier to a world list for a resource that specifies which world identifiers supported by the integrated circuit are authorized for access to the resource; and a data store configured to store world error data, including the tagged world identifier of a memory request that has been rejected by the world identifier checker circuitry.

Error management in system on a chip with securely partitioned memory space

Described is a translation lookaside buffer (TLB) prefetcher with multi-level TLB prefetches and feedback architecture. A processing system includes two or more translation lookaside buffer (TLB) levels, each TLB level including a miss queue, and a TLB prefetcher connected to each of the two or more TLB levels. The TLB prefetcher configured to receive feedback from the miss queue at each TLB level for previously sent TLB prefetches and control number of TLB prefetches sent for a trained TLB entry to each TLB level of the two or more TLB levels based on the feedback.

Translation lookaside buffer (TLB) prefetcher with multi-level TLB prefetches and feedback architecture

Systems and methods are disclosed for logging guest physical address for memory access faults. For example, a method for logging guest physical address includes receiving a first address translation request from a processor pipeline at a translation lookaside buffer for a first guest virtual address; identifying a hit with a fault condition corresponding to the first guest virtual address; responsive to the fault condition, invoking a single-stage page table walk with the first guest virtual address to obtain a first guest physical address; and storing the first guest physical address with the first guest virtual address in a data store, wherein the data store is separate from an entry in the translation lookaside buffer that includes a tag that includes the first guest virtual address and data that includes a physical address.

Logging guest physical address for memory access faults

Described are methods and a system for atomic memory operations with contended cache lines. A processing system includes at least two cores, each core having a local cache, and a lower level cache in communication with each local cache. One local cache configured to request a cache line to execute an atomic memory operation (AMO) instruction, receive the cache line via the lower level cache, receive a probe downgrade due to other local cache requesting the cache line prior to execution of the AMO, and send the AMO instruction to the lower level cache for remote execution in response to the probe downgrade.

Method for executing atomic memory operations when contested

Described is a data cache with prediction hints for a cache hit. The data cache includes a plurality of cache lines, where a cache line includes a data field, a tag field, and a prediction hint field. The prediction hint field is configured to store a prediction hint which directs alternate behavior for a cache hit against the cache line. The prediction hint field is integrated with the tag field or is integrated with a way predictor field.

Data cache with prediction hints for cache hits

Described is a data cache implementing hybrid writebacks and writethroughs. A processing system includes a memory, a memory controller, and a processor. The processor includes a data cache including cache lines, a write buffer, and a store queue. The store queue writes data to a hit cache line and an allocated entry in the write buffer when the hit cache line is initially in at least a shared coherence state, resulting in the hit cache line being in a shared coherence state with data and the allocated entry being in a modified coherence state with data. The write buffer requests and the memory controller upgrades the hit cache line to a modified coherence state with data based on tracked coherence states. The write buffer retires the data upon upgrade. The data cache writebacks the data to memory for a defined event.

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Sunnyvale, CA, United States of America

John Ingalls