2.4.1 HN-F exclusive accesses

The HN-F supports exclusive access on ReadNoSnp, WriteNoSnp, ReadShared, ReadClean, and CleanUnique transactions to any address that maps to the HN-F.


The RN-F generates:

  • ReadNoSnp and WriteNoSnp exclusives for memory locations that are marked Non-cacheable or Device.
  • ReadShared, ReadClean, and CleanUnique exclusives are used for Shareable and coherent memory locations.

Each HN-F partition includes 32 exclusive monitors for tracking these transaction types, and each monitor can operate as both a PoC monitor and System monitor, as defined by the CHI architecture.

For each of the 2 (6XP/2HNF) or 4 (8XP/4HNF) HN-F partitions, only 32 unique logical threads, either processor or device threads, designated by a unique SrcID or LPID, can access the exclusive monitors of that HN-F during one instance of the CCN-502 operation, from reset deassertion to reset assertion. This is because these monitors are permanently assigned to a logical thread on the first exclusive access by that thread, and are not then available to any other thread.

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