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ERR<n>MISC2, Error Record Miscellaneous Register 2, n = 0 - 65534

The ERR<n>MISC2 characteristics are:


IMPLEMENTATION DEFINED error syndrome register. The miscellaneous syndrome registers might contain:

  • Information to identify the FRU in which the error was detected, and might contain enough information to locate the error within that FRU.
  • A Corrected error counter or counters.
  • Other state information not present in the corresponding status and address registers.


This register is present only when error record <n> is implemented. Otherwise, direct accesses to ERR<n>MISC2 are RES0.

ERR<q>FR describes the features implemented by the node that owns error record <n>. <q> is the index of the first error record owned by the same node as error record <n>. If the node owns a single record, then q = n.

For IMPLEMENTATION DEFINED fields in ERR<n>MISC2, writing zero must always be supported to return the error record to an initial quiescent state.

In particular, if any IMPLEMENTATION DEFINED syndrome fields might generate a Fault Handling or Error Recovery Interrupt request, writing zero is sufficient to deactivate the Interrupt request.

Fields that are read-only, non-zero, and ignore writes are compliant with this requirement.

If RAS System Architecture v1.1 is not implemented, Arm recommendeds that ERR<n>MISC2 does not require zeroing to return the record to a quiescent state.


Arm recommends that any IMPLEMENTATION DEFINED syndrome fields that can generate a Fault Handling, Error Recovery, Critical, or IMPLEMENTATION DEFINED, interrupt request are disabled at Cold reset and are enabled by software writing an IMPLEMENTATION DEFINED non-zero value to an IMPLEMENTATION DEFINED field in ERR<q>CTRL.

It is IMPLEMENTATION DEFINED whether ERR<n>MISC2 is present if RAS System Architecture v1.1 is not implemented. ERR<n>MISC2 is RES0 if not present.


ERR<n>MISC2 is a 64-bit register.

Field descriptions

The ERR<n>MISC2 bit assignments are:





Accessing the ERR<n>MISC2

Reads from ERR<n>MISC2 return an IMPLEMENTATION DEFINED value and writes have IMPLEMENTATION DEFINED behavior.

Arm recommends that miscellaneous syndrome for multiple errors, such as a corrected error counter, is read/write.

When ERR<n>STATUS.MV == 0b1, the miscellaneous syndrome specific to the most recently recorded error should ignore writes.


These recommendations allow a counter to be reset in the presence of a persistent error, while preventing specific information, such as that identifying a FRU, from being lost if an error is detected while the previous error is being logged.

ERR<n>MISC2 can be accessed through the memory-mapped interfaces:

RAS0x030 + 64nERR<n>MISC2

Accesses on this interface are RW.