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SPARC JPS1 Implementation Supplement:
Fujitsu SPARC64 V
• Release 1.0, 1 July 2002
■
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
ASI_AFSR.CE_INCOMED
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
UE
s 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: