Specification Update

Errata
Specification Update 39
AZ49. RSM Instruction Execution under Certain Conditions May Cause
Processor Hang or Unexpected Instruction Execution Results
Problem: Problem: RSM instruction execution, under certain conditions triggered by a complex
sequence of internal processor micro-architectural events, may lead to processor hang,
or unexpected instruction execution results.
Implication: In the above sequence, the processor may live lock or hang, or RSM instruction may
restart the interrupted processor context through a nondeterministic EIP offset in the
code segment, resulting in unexpected instruction execution, unexpected exceptions or
system hang. Intel has not observed this erratum with any commercially available
software.
Workaround: It is possible for the BIOS to contain a workaround for this erratum.
Status: For the steppings affected, see the Summary Tables of Changes.
AZ50. Benign Exception after a Double Fault May Not Cause a Triple Fault
Shutdown
Problem: According to the Intel® 64 and IA-32 Architectures Software Developer's Manual,
Volume 3A, “Exception and Interrupt Reference”, if another exception occurs while
attempting to call the double-fault handler, the processor enters shutdown mode. Due to
this erratum, any benign faults while attempting to call double-fault handler will not
cause a shutdown. However Contributory Exceptions and Page Faults will continue to
cause a triple fault shutdown.
Implication: If a benign exception occurs while attempting to call the double-fault handler, the
processor may hang or may handle the benign exception. Intel has not observed this
erratum with any commercially available software.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.