Datasheet

Errata
Specification Update 59
AH44. Performance Monitor IDLE_DURING_DIV (18h) Count May Not Be
Accurate
Problem: Performance monitoring events that count the number of cycles the divider is busy
and no other execution unit operation or load operation is in progress may not be
accurate.
Implication: The counter may reflect a value higher or lower than the actual number of events.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.
AH45. Values for LBR/BTS/BTM Will Be Incorrect after an Exit from SMM
Problem: After a return from SMM (System Management Mode), the CPU will incorrectly update
the LBR (Last Branch Record) and the BTS (Branch Trace Store), hence rendering their
data invalid. The corresponding data if sent out as a BTM on the system bus will also
be incorrect.
Note: This issue would only occur when one of the 3 above mentioned debug support
facilities are used.
Implication: The value of the LBR, BTS, and BTM immediately after an RSM operation should not be
used.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.
AH46. Shutdown Condition May Disable Non-Bootstrap Processors
Problem: When a logical processor encounters an error resulting in shutdown, non-bootstrap
processors in the package may be unexpectedly disabled.
Implication: Non-bootstrap logical processors in the package that have not observed the error
condition may be disabled and may not respond to INIT#, SMI#, NMI#, SIPI or other
events.
Workaround: When this erratum occurs, RESET# must be asserted to restore multi-core
functionality.
Status: For the steppings affected, see the Summary Tables of Changes.