Datasheet
Errata
76 Specification Update
AH90. Page Access Bit May Be Set Prior to Signaling a Code Segment Limit
Fault
Problem: If code segment limit is set close to the end of a code page, then due to this erratum
the memory page Access bit (A bit) may be set for the subsequent page prior to
general protection fault on code segment limit.
Implication: When this erratum occurs, a non-accessed page present in memory following a page
that contains the code segment limit may be tagged as accessed
Workaround: Non-present or non-executable page can be placed after the limit of the code segment
to prevent this erratum.
Status: For the steppings affected, see the Summary Tables of Changes.
AH91. Update of Attribute Bits on Page Directories without Immediate TLB
Shootdown May Cause Unexpected Processor Behavior
Problem: Updating a page directory entry (or page map level 4 table entry or page directory
pointer table entry in IA-32e mode) by changing R/W, U/S or P bits without immediate
TLB shootdown (as described by the 4 step procedure in "Propagation of Page Table
and Page Directory Entry Changes to Multiple Processors" In Volume 3A of the Intel
®
64 and IA-32 Architectures Software Developer’s Manual), in conjunction with a
complex sequence of internal processor micro-architectural events, may lead to
unexpected processor behavior.
Implication: This erratum may lead to livelock, shutdown or other unexpected processor behavior.
Intel has not observed this erratum with any commercially available system.
Workaround: It is possible for BIOS to contain a workaround for this erratum.
Status: For the steppings affected, see the Summary Tables of Changes.
AH92. Invalid Instructions May Lead to Unexpected Behavior
Problem: Invalid instructions due to undefined opcodes or instructions exceeding the maximum
instruction length (due to redundant prefixes placed before the instruction) may lead,
under complex circumstances, to unexpected behavior.
Implication: The processor may behave unexpectedly due to invalid instructions. 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.