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BJ19.
LBR, BTS, BTM May Report a Wrong Address when an Exception/
Interrupt Occurs in 64-bit Mode
Problem:
An exception/interrupt event should be transparent to the LBR (Last Branch Record),
BTS (Branch Trace Store) and BTM (Branch Trace Message) mechanisms. However,
during a specific boundary condition where the exception/interrupt occurs right after
the execution of an instruction at the lower canonical boundary (0x00007FFFFFFFFFFF)
in 64-bit mode, the LBR return registers will save a wrong return address with bits 63
to 48 incorrectly sign extended to all 1's. Subsequent BTS and BTM operations which
report the LBR will also be incorrect.
Implication:
LBR, BTS and BTM may report incorrect information in the event of an exception/
interrupt.
Workaround:
None identified.
Status:
For the steppings affected, see the Summary Tables of Changes.
BJ20.
MCi_Status Overflow Bit May Be Incorrectly Set on a Single Instance
of a DTLB Error
Problem:
A single Data Translation Look Aside Buffer (DTLB) error can incorrectly set the
Overflow (bit [62]) in the MCi_Status register. A DTLB error is indicated by MCA error
code (bits [15:0]) appearing as binary value, 000x 0000 0001 0100, in the MCi_Status
register.
Implication:
Due to this erratum, the Overflow bit in the MCi_Status register may not be an accurate
indication of multiple occurrences of DTLB errors. There is no other impact to normal
processor functionality.
Workaround:
None identified.
Status:
For the steppings affected, see the Summary Tables of Changes.
BJ21.
MONITOR or CLFLUSH on the Local XAPIC's Address Space Results in
Hang
Problem:
If the target linear address range for a MONITOR or CLFLUSH is mapped to the local
xAPIC's address space, the processor will hang.
Implication:
When this erratum occurs, the processor will hang. The local xAPIC's address space
must be uncached. The MONITOR instruction only functions correctly if the specified
linear address range is of the type write-back. CLFLUSH flushes data from the cache.
Intel has not observed this erratum with any commercially available software.
Workaround:
Do not execute MONITOR or CLFLUSH instructions on the local xAPIC address space.
Status:
For the steppings affected, see the Summary Tables of Changes.
26
Specification Update
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