Errata
Intel
®
Core
™
2 Duo Processor
Specification Update
27
Workaround:
Any vector programmed into an LVT entry must have an ISR associated with
it, even if that vector was programmed as masked. This ISR routine must do
an EOI to clear any unexpected interrupts that may occur. The ISR
associated with the spurious vector does not generate an EOI, therefore the
spurious vector should not be used when writing the LVT.
Status:
For the steppings affected, see the Summary Tables of Changes.
AW26.
Pending x87 FPU Exceptions (#MF) Following STI May Be Serviced
Before Higher Priority Interrupts
Problem:
Interrupts that are pending prior to the execution of the STI (Set Interrupt
Flag) instruction are normally serviced immediately after the instruction
following the STI. An exception to this is if the following instruction triggers a
#MF. In this situation, the interrupt should be serviced before the #MF.
Because of this erratum, if following STI, an instruction that triggers a #MF is
executed while STPCLK#, Enhanced Intel SpeedStep® Technology transitions
or Thermal Monitor 1 events occur, the pending #MF may be serviced before
higher priority interrupts.
Implication:
Software may observe #MF being serviced before higher priority interrupts.
Workaround:
None identified.
Status:
For the steppings affected, see the Summary Tables of Changes.
AW27.
VERW/VERR/LSL/LAR Instructions May Unexpectedly Update the Last
Exception Record (LER) MSR
Problem:
The LER MSR may be unexpectedly updated, if the resultant value of the Zero
Flag (ZF) is zero after executing the following instructions
1. VERR (ZF=0 indicates unsuccessful segment read verification)
2. VERW (ZF=0 indicates unsuccessful segment write verification)
3. LAR (ZF=0 indicates unsuccessful access rights load)
4. LSL (ZF=0 indicates unsuccessful segment limit load)
Implication:
The value of the LER MSR may be inaccurate if VERW/VERR/LSL/LAR
instructions are executed after the occurrence of an exception.
Workaround:
Software exception handlers that rely on the LER MSR value should read the
LER MSR before executing VERW/VERR/LSL/LAR instructions.
Status:
For the steppings affected, see the Summary Tables of Changes.
AW28.
INIT Does Not Clear Global Entries in the TLB
Problem:
INIT may not flush a TLB entry when:
•
The processor is in protected mode with paging enabled and the page
global enable flag is set (PGE bit of CR4 register)
•
G bit for the page table entry is set
