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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; 6+ 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] 6+ 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; 6+ 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] 6+ 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; 6+ 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] 6+ 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; 6+ 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] 6+ 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; 6+ 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] 6+ messages in thread
[parent not found: <bug-39677-4@http.gcc.gnu.org/bugzilla/>]
* [Bug target/39677] AMD Opteron E needs workaround for lock erratum [not found] <bug-39677-4@http.gcc.gnu.org/bugzilla/> @ 2021-07-19 18:28 ` pinskia at gcc dot gnu.org 0 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-07-19 18:28 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39677 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |INVALID --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So reading https://www.amd.com/system/files/TechDocs/25759.pdf and errata #147, the errata only occurs if lock is not there: The erratum will not occur if there is a LOCK prefix on the read-modify-write instruction. And GCC never emits a cmpxchg without a lock prefix so there is nothing to be done. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-07-19 18:28 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 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 [not found] <bug-39677-4@http.gcc.gnu.org/bugzilla/> 2021-07-19 18:28 ` pinskia at gcc dot gnu.org
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