linux-kernel - Opteron Rev E has a bug ... a locked instruction doesn't act as a read-acquire barrier

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Message-Id: <200808031106.12366.arekm@maven.pl>
Date:	Sun, 3 Aug 2008 11:06:12 +0200
From:	Arkadiusz Miskiewicz <arekm@...en.pl>
To:	linux-kernel@...r.kernel.org
Subject: Opteron Rev E has a bug ... a locked  instruction doesn't act as a read-acquire barrier


Hello,

http://google-perftools.googlecode.com/svn-history/r48/trunk/src/base/atomicops-internals-x86.cc
says

"  // Opteron Rev E has a bug in which on very rare occasions a locked
  // instruction doesn't act as a read-acquire barrier if followed by a
  // non-locked read-modify-write instruction.  Rev F has this bug in 
  // pre-release versions, but not in versions released to customers,
  // so we test only for Rev E, which is family 15, model 32..63 inclusive.
  if (strcmp(vendor, "AuthenticAMD") == 0 &&       // AMD
      family == 15 &&
      32 <= model && model <= 63) {
    AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug = true;
  } else {
    AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug = false;
  }
"

does kernel have quirk/workaround for this? I'm looking at arch/x86/kernel/cpu 
but I don't see workaround related to this (possibly I'm overlooking).

-- 
Arkadiusz Miśkiewicz        PLD/Linux Team
arekm / maven.pl            http://ftp.pld-linux.org/
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