Datasheet

Errata
Specification Update 79
AH98. Updating Code Page Directory Attributes without TLB Invalidation May
Result in Improper Handling of Code #PF
Problem: Code #PF (Page Fault exception) is normally handled in lower priority order relative to
both code #DB (Debug Exception) and code Segment Limit Violation #GP (General
Protection Fault). Due to this erratum, code #PF may be handled incorrectly, if all of
the following conditions are met:
Problem: A PDE (Page Directory Entry) is modified without invalidating the corresponding TLB
(Translation Look-aside Buffer) entry
Problem: Code execution transitions to a different code page such that both
 The target linear address corresponds to the modified PDE
 The PTE (Page Table Entry) for the target linear address has an A (Accessed)
bit that is clear
Problem: One of the following simultaneous exception conditions is present following the code
transition
 Code #DB and code #PF
 Code Segment Limit Violation #GP and code #PF
Implication: Software may observe either incorrect processing of code #PF before code Segment
Limit Violation #GP or processing of code #PF in lieu of code #DB.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.