Specification Update 31
HSD53. The From-IP for Branch Tracing May be Incorrect
Problem: BTM (Branch Trace Message) and BTS (Branch Trace Store) report the “From-IP”
indicating the source address of the branch instruction. Due to this erratum, BTM and
BTS may repeat the “From-IP” value previously reported. The “To-IP” value is not
affected.
Implication: Using BTM or BTS reports to reconstruct program execution may be unreliable.
Workaround: It is possible for the BIOS to contain a workaround for this erratum.
Status: For the steppings affected, see the Summary Table of Changes.
HSD54. TM1 Throttling May Continue indefinitely
Problem: TM1 (Thermal Monitor 1) throttling may continue when the processor’s temperature
decreases below the throttling point while the processor is in Package C3 or deeper.
Implication: The processor will continue thermal throttling but does not indicate it is hot.
Workaround: It is possible for the BIOS to contain a workaround for this erratum.
Status: For the steppings affected, see the Summary Table of Changes.
HSD55. Internal Parity Errors May Incorrectly Report Overflow in The IA32_MCi_STATUS MSR
Problem: Due to this erratum, uncorrectable internal parity error reports with an
IA32_MCi_STATUS.MCACOD (bits [15:0]) value of 0005H and an
IA32_MCi_STATUS.MSCOD (bits [31:16]) value of 0004H may incorrectly set the
IA32_MCi_STATUS.OVER flag (bit 62) indicating an overflow even when only a single
error has been observed.
Implication: IA32_MCi_STATUS.OVER may not accurately indicate multiple occurrences of
uncorrectable internal parity errors. There is no other impact to normal processor
functionality.
Workaround: None identified.
Status: For the steppings affected, see the Summary Table of Changes.
HSD56. Performance Monitor Events OTHER_ASSISTS.AVX_TO_SSE And OTHER_ASSISTS.SSE_TO_AVX May Over Count
Problem: The Performance Monitor events OTHER_ASSISTS.AVX_TO_SSE (Event C1H; Umask
08H) and OTHER_ASSISTS.SSE_TO_AVX (Event C1H; Umask 10H) incorrectly
increment and over count when an HLE (Hardware Lock Elision) abort occurs.
Implication: The Performance Monitor Events OTHER_ASSISTS.AVX_TO_SSE And
OTHER_ASSISTS.SSE_TO_AVX may over count.
Workaround: None identified.
Status: For the steppings affected, see the Summary Table of Changes.
HSD57. Processor May Run at Incorrect P-State
Problem: The processor package may use stale software P-State (performance state) requests
when one or more logical processors are idle.
Implication: The processor package may run at a higher or lower than expected P-State. This issue
may persist as long as any logical processor is idle.
Workaround: It is possible for the BIOS to contain a workaround for this erratum.
Status: For the steppings affected, see the Summary Table of Changes.