64-bit Intel
®
Xeon
®
Processor with 800 MHz System Bus
35
(1 MB and 2 MB L2 Cache Versions) Specification Update
Errata
S62
The Execute Disable Bit fault may be reported before other types of page
fault when both occur
Problem:
If the Execute Disable Bit is enabled and both the Execute Disable Bit fault and page faults occur,
the Execute Disable Bit fault will be reported prior to other types of page fault being reported.
Implication:
No impact to properly written code since both types of faults will be generated but in the opposite
order.
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
.
S63
Writes to IA32_MISC_ENABLE may not update flags for both logical
processors
Problem:
On processors supporting HT Technology with Execute Disable Bit feature, writes to
IA32_MISC_ENABLE may only update IA32_EFER.NXE for the current logical processor.
Implication:
Due to this erratum, the non-current logical processor may not update its IA32_EFER.NXE bit.
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
.
S64
Execute Disable Bit set with CR4.PAE may cause livelock
Problem:
If the Execute Disable bit of IA32_MISC_Enable is set along with the PAE bit of CR4
(IA32_EFER.NXE & CR4.PAE), the processor may livelock.
Implication:
When this erratum occurs, the processor may livelock resulting in a system hang or operating
system failure.
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
.
S65
SYSENTER or SYSEXIT instructions may experience incorrect canonical
address checking on processors supporting Intel
®
Extended Memory 64
Technology (Intel
®
EM64T)
Problem:
Processors which support Intel EM64T always perform canonical address checks before accessing
memory. SYSENTER or SYSEXIT instructions may check an incorrect address.
Implication:
Due to this erratum, an unexpected #GP fault may occur, or a reference to a non-canonical address
without a #GP fault may occur.
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
.
S66
Checking of Page Table Base Address may not match Address Bit Width
supported by the platform
Problem:
If the page table base address included in the page map level-4 table, page-directory pointer table,
page-directory table, or page table exceeds the physical address range supported by the platform
(e.g. 36 bits) and it is less than the implemented address range (e.g. 40 bits), the processor does not
check to see if the address is invalid.
Implication:
If software sets such an invalid physical address in the listed tables, the processor does not generate
a page fault (#PF) upon accessing that virtual address, and the access results in an incorrect read or
write. If BIOS provides only valid physical address ranges to the operating system, this erratum
will not occur.
Workaround:
Ensure that BIOS provides only valid physical address ranges to the operating system.
