Specification Update

Errata
74 Specification Update
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.
W100. CS Limit Violation on RSM May be Serviced before Higher
Priority Interrupts/Exceptions
Problem: When the processor encounters a CS (Code Segment) limit violation, a
#GP (General Protection Exception) fault is generated after all higher
priority Interrupts and exceptions are serviced. Because of this erratum,
if RSM (Resume from System Management Mode) returns to execution
flow where a CS limit violation occurs, the #GP fault may be serviced
before a higher priority Interrupt or Exception (for example NMI (Non-
Maskable Interrupt), Debug break (#DB), Machine Check (#MC), etc.).
Implication: Operating systems may observe a #GP fault being serviced before
higher priority Interrupts and Exceptions.
Workaround: None Identified.
Status: For the steppings affected, see the Summary Tables of Changes.
W101. Count Value for Performance-Monitoring Counter
PMH_PAGE_WALK May Be Incorrect
Problem: Performance-Monitoring Counter PMH_PAGE_WALK is used to count the
number of page walks resulting from Data Translation Look-Aside
Buffer (DTLB) and Instruction Translation Look-Aside (ITLB) misses.
Under certain conditions, this counter may be incorrect.
Implication: There may be small errors in the accuracy of the counter.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.
W102. Performance Monitoring Event For Number of Reference
Cycles When the Processor Is Not Halted (3CH) Does Not
Count According to the Specification
Problem: The CPU_CLK_UNHALTED performance monitor with mask 1 counts bus
clock cycles instead of counting the core clock cycles at the maximum
possible ratio. The maximum possible ratio is computed by dividing the
maximum possible core frequency by the bus frequency.
Implication: The CPU_CLK_UNHALTED performance monitor with mask 1 counts a
value lower than expected. The value is lower by exactly one multiple
of the maximum possible ratio.
Workaround: Multiply the performance monitor value by the maximum possible ratio.
Status: For the steppings affected, see the Summary Tables of Changes.