AMD 3200 Revision History - Page 38

Last-Branch, Record, Enabled, Cause, Machine, Check, Incorrect, LastBranchToIp

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Revision Guide for AMD Family 15h Models 00h-0Fh Processors 48063 Rev. 3.18 October 2012 593 Last-Branch Record Enabled May Cause Machine Check and Incorrect LastBranchToIp Description When LBR is enabled, a complex interaction between two threads of the same compute-unit may result in the processor core reporting an incorrect value in the LastBranchToIp register (MSR0000_01DC). Potential Effect on System In rare circumstances, the value reported in LastBranchToIP may present incorrect debug information. The processor may also report an uncorrectable machine check exception for a branch status register parity error, simultaneous to the above error. MC1_STATUS[ErrorCodeExt] (MSR0000_0405[20:16]) = 00110b identifies a branch status register parity error. Suggested Workaround BIOS should set MSRC001_0045[15] = 1b (MC1_CTL_MASK[BSRP]). This workaround does not resolve the potential for an incorrect address to be provided in LastBranchToIp. This latter effect has negligible impact on debugging due to the low probability of the error occurring when this data is being collected. No workaround is required for this aspect. Fix Planned Yes 38 Product Errata

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593
Last-Branch
Record
Enabled
May
Cause
Machine
Check
and
Incorrect
LastBranchToIp
Description
When
LBR
is
enabled
,
a
complex
interaction
between
two
threads
of
the
same
compute-unit
may
result
in
the
processor
core
reporting
an
incorrect
value
in
the
LastBranchToIp
register
(
MSR
0000_01
DC
.
Potential
Effect
on
System
In
rare
circumstances
,
the
value
reported
in
LastBranchToIP
may
present
incorrect
debug
information
.
The
processor
may
also
report
an
uncorrectable
machine
check
exception
for
a
branch
status
register
parity
error
,
simultaneous
to
the
above
error
.
MC
1_
STATUS
[
ErrorCodeExt
] (
MSR
0000_0405[20:16] = 00110
b
identifies
a
branch
status
register
parity
error
.
Suggested
Workaround
BIOS
should
set
MSRC
001_0045[15] = 1
b
(
MC
1_
CTL
_
MASK
[
BSRP
].
This
workaround
does
not
resolve
the
potential
for
an
incorrect
address
to
be
provided
in
LastBranchToIp
.
This
latter
effect
has
negligible
impact
on
debugging
due
to
the
low
probability
of
the
error
occurring
when
this
data
is
being
collected
.
No
workaround
is
required
for
this
aspect
.
Fix
Planned
Yes
Revision
Guide
for
AMD
Family
15
h
Models
00
h-
0
Fh
Processors
48063
Rev
. 3.18
October
2012
38
Product
Errata