9. Error Protection and Handling
errors consist of:
- Primary instruction cache array parity errors
- Primary data cache array parity errors
- Secondary cache tag array uncorrectable ECC errors
- Secondary cache data array uncorrectable ECC errors
- System interface command bus parity errors
- System interface address/data bus uncorrectable ECC errors
- System interface response bus parity errors
When the processor detects an uncorrectable error, a Cache Error exception is posted. In general, the detection of an uncorrectable error does not disrupt any ongoing operations. However, the instruction fetch and load/store units never use data which contains an uncorrectable error.
To inform the external agent, the processor asserts SysUncErr* for one SysClk cycle whenever any of the following uncorrectable errors are detected:
- Primary instruction cache tag array parity errors
- Primary data cache tag array parity errors
- Secondary cache tag array uncorrectable ECC errors
- System interface command bus parity errors
- System interface address/data bus external address cycle uncorrectable ECC errors
- System interface response bus parity errors.
The processor informs the external agent that an uncorrectable tag error has been detected by asserting SysUncErr* for one SysClk cycle.
