Fujitsu Fujitsu SPARC64 V manual Correctable Error on Extended UPA Data Bus

ASI_AFSR.CE_INCOMED

■Raw (unmarked) uncorrectable error (multibit error)

■Marked uncorrectable error

Correctable Error on Extended UPA Data Bus

When the SPARC64 V processor detects a correctable error in the extended UPA incoming data, the processor corrects the data and uses it. The restrainable error

is indicated.

When the processor detects a correctable error in the outgoing data to the extended UPA data bus before the data transfer occurs, it corrects the error and sends the corrected data to the extended UPA data bus. If the correctable error is also detected in the data in the U2 cache, the processor corrects the source data in the U2 cache, too. The error is not reported to software.

Uncorrectable Error in Incoming Data from Extended UPA Data Bus

At the time data is received, the SPARC64 V processor handles UEs in data coming from the extended UPA data bus, as follows:

■Marked UE in incoming data from the extended UPA data bus. When the processor detects a marked UE in such data, the processor transfers that data to the destination register or cache without modification. The error is not reported to software when the marked UE is received at the extended UPA data bus interface.

■Raw UE in incoming data from the extended UPA data bus. When the processor detects a raw UE in such data, the processor applies error marking to that data. The processor changes the data to marked UE with ERROR_MARK_ID = 0, indicating a memory system error, and then transfers the marked UE data to the destination register or cache.

If the error marking is applied to incoming cacheable data, the restrainable error ASI_AFSR.UE_RAW_L2$FILL is indicated. If the error marking is applied to incoming noncacheable data, the error is not reported to software at the time of error marking.

Note – The destination register or cache always receives the marked UE data for both marked UE and raw UE in the data sent via the extended UPA data bus, as described above.

Finally, the treatment of an uncorrectable error (UE) coming from the extended UPA bus depends on whether the access was to cacheable or noncacheable data and whether the access was an instruction fetch, load, or store instruction, as follows:

198 SPARC JPS1 Implementation Supplement: Fujitsu SPARC64 V • Release 1.0, 1 July 2002