Storing a system-absolute address (SAA) in a first level translation look-aside buffer (TLB)

摘要

Embodiments relate to a method, system and computer program product for storing a system-absolute address (SAA) in a first level look-aside buffer (TLB). In one embodiment, the system includes a central processor including the TLB and general purpose registers (GPRS). The TLB is configured for storing the SAA. The central processor is configured for issuing a load system-absolute address (LSAA) instruction. The system includes a translation unit that is in communication with the TLB of the central processor. The system is configured to perform a method including determining, based on the LSAA instruction being issued, whether the SAA is stored in the TLB. The method includes sending a translation request to the translation unit from the central processor based on the SAA not being stored in the TLB. The method includes determining the SAA by the translation unit based on receiving the translation request.

主权项

1. A computer system for storing a system-absolute address (SAA) in a first level look-aside buffer (TLB), the system comprising:
a central processor including the first level TLB and general purpose registers (GPRS), the first level TLB configured for storing the SAA, the central processor configured for issuing a load system-absolute address (LSAA) instruction; a directory; access exception checking logic; and a translation unit in communication with the first level TLB of the central processor, the translation unit being distinct from the central processor, the translation unit configured for storing a second level TLB that is distinct from the first level TLB, the system configured to perform a method comprising:
determining, based on the LSAA instruction being issued, whether the SAA is stored in the first level TLB;sending a translation request to the translation unit from the central processor based on the SAA not being stored in the first level TLB;determining the SAA by the translation unit based on receiving the translation request by looking up the SAA in a second level TLB that is located on the translation unit;sending the SAA from the translation unit to the first level TLB and writing the SAA to the first level TLB;restarting the LSAA instruction by the central processor;determining that the SAA is stored in an entry in each of the first level TLB and the directory;obtaining the SAA and a page protection bit corresponding to the SAA from the first level TLB based on the LSAA instruction being issued;sending the page protection bit to the access exception checking logic;writing the SAA and a page size to the GPRS;while writing the SAA to the GPRS, performing access exception checking for the SAA by the access checking logic based on the page protection bit, the access exception checking comprising:
based on the page protection bit having a first value, only checking for fetch-type access exceptions corresponding to the SAA; andbased on the page protection bit having a second value that is distinct from the first value, checking for both fetch-type access exceptions and store-type access exceptions corresponding to the SAA; andproviding the SAA from the GPRS to an accelerator.