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* [Bug middle-end/39677] New: AMD Opteron E needs workaround for lock erratum
@ 2009-04-07 13:36 bonzini at gnu dot org
2009-04-07 13:42 ` [Bug middle-end/39677] " bonzini at gnu dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: bonzini at gnu dot org @ 2009-04-07 13:36 UTC (permalink / raw)
To: gcc-bugs
From
http://code.google.com/p/google-perftools/source/browse/trunk/src/base/atomicops-internals-x86.h
bool has_amd_lock_mb_bug; // Processor has AMD memory-barrier bug; do lfence
// after acquire compare-and-swap.
...
inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
Atomic32 old_value,
Atomic32 new_value) {
Atomic32 prev;
__asm__ __volatile__("lock; cmpxchgl %1,%2"
: "=a" (prev)
: "q" (new_value), "m" (*ptr), "0" (old_value)
: "memory");
return prev;
}
inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
Atomic32 old_value,
Atomic32 new_value) {
Atomic32 x = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
if (AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug) {
__asm__ __volatile__("lfence" : : : "memory");
}
return x;
}
inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
Atomic32 old_value,
Atomic32 new_value) {
return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
}
This bug can also affect lock+xadd combinations.
--
Summary: AMD Opteron E needs workaround for lock erratum
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Keywords: openmp
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: bonzini at gnu dot org
GCC target triplet: i386-*-*, x86_64-*-*
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39677
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/39677] AMD Opteron E needs workaround for lock erratum
2009-04-07 13:36 [Bug middle-end/39677] New: AMD Opteron E needs workaround for lock erratum bonzini at gnu dot org
@ 2009-04-07 13:42 ` bonzini at gnu dot org
2009-04-07 15:02 ` bonzini at gnu dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: bonzini at gnu dot org @ 2009-04-07 13:42 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from bonzini at gnu dot org 2009-04-07 13:42 -------
More info from Solaris bug # 6323525:
if (number_of_cores() < 2) then don't have bug
if (family == 0xf && Model < 0x40) then have bug
if (rdmsr(MSR_BU_CFG/*0xC0011023*/) & 2) then bug is masked
See also http://bugzilla.kernel.org/show_bug.cgi?id=11305
--
bonzini at gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2009-04-07 13:42:25
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39677
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/39677] AMD Opteron E needs workaround for lock erratum
2009-04-07 13:36 [Bug middle-end/39677] New: AMD Opteron E needs workaround for lock erratum bonzini at gnu dot org
2009-04-07 13:42 ` [Bug middle-end/39677] " bonzini at gnu dot org
@ 2009-04-07 15:02 ` bonzini at gnu dot org
2009-10-13 1:07 ` [Bug target/39677] " rth at gcc dot gnu dot org
2009-12-07 16:12 ` rth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: bonzini at gnu dot org @ 2009-04-07 15:02 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from bonzini at gnu dot org 2009-04-07 15:02 -------
I cannot see any better alternative, but I'll point out that saying
"wrong-code" is not exact.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39677
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/39677] AMD Opteron E needs workaround for lock erratum
2009-04-07 13:36 [Bug middle-end/39677] New: AMD Opteron E needs workaround for lock erratum bonzini at gnu dot org
2009-04-07 13:42 ` [Bug middle-end/39677] " bonzini at gnu dot org
2009-04-07 15:02 ` bonzini at gnu dot org
@ 2009-10-13 1:07 ` rth at gcc dot gnu dot org
2009-12-07 16:12 ` rth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: rth at gcc dot gnu dot org @ 2009-10-13 1:07 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from rth at gcc dot gnu dot org 2009-10-13 01:07 -------
Not an openmp bug; we've got to make the change for all code gcc generates.
--
rth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |rth at gcc dot gnu dot org
|dot org |
Status|NEW |ASSIGNED
Component|middle-end |target
Keywords|openmp |
Last reconfirmed|2009-04-07 13:42:25 |2009-10-13 01:07:32
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39677
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/39677] AMD Opteron E needs workaround for lock erratum
2009-04-07 13:36 [Bug middle-end/39677] New: AMD Opteron E needs workaround for lock erratum bonzini at gnu dot org
` (2 preceding siblings ...)
2009-10-13 1:07 ` [Bug target/39677] " rth at gcc dot gnu dot org
@ 2009-12-07 16:12 ` rth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: rth at gcc dot gnu dot org @ 2009-12-07 16:12 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from rth at gcc dot gnu dot org 2009-12-07 16:12 -------
Not working on it any longer.
--
rth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|rth at gcc dot gnu dot org |unassigned at gcc dot gnu
| |dot org
Status|ASSIGNED |NEW
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39677
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2009-12-07 16:12 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2009-04-07 13:36 [Bug middle-end/39677] New: AMD Opteron E needs workaround for lock erratum bonzini at gnu dot org
2009-04-07 13:42 ` [Bug middle-end/39677] " bonzini at gnu dot org
2009-04-07 15:02 ` bonzini at gnu dot org
2009-10-13 1:07 ` [Bug target/39677] " rth at gcc dot gnu dot org
2009-12-07 16:12 ` rth at gcc dot gnu dot org
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