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authorDesnes A. Nunes do Rosario <desnesn@linux.ibm.com>2020-02-27 10:47:15 -0300
committerMichael Ellerman <mpe@ellerman.id.au>2020-02-28 10:09:33 +1100
commitfc37a1632d40c80c067eb1bc235139f5867a2667 (patch)
tree3d2cc770e40e05a4072d7affee44e15d12cdaa5c
parentcb0cc635c7a9fa8a3a0f75d4d896721819c63add (diff)
powerpc: fix hardware PMU exception bug on PowerVM compatibility mode systems
PowerVM systems running compatibility mode on a few Power8 revisions are still vulnerable to the hardware defect that loses PMU exceptions arriving prior to a context switch. The software fix for this issue is enabled through the CPU_FTR_PMAO_BUG cpu_feature bit, nevertheless this bit also needs to be set for PowerVM compatibility mode systems. Fixes: 68f2f0d431d9ea4 ("powerpc: Add a cpu feature CPU_FTR_PMAO_BUG") Signed-off-by: Desnes A. Nunes do Rosario <desnesn@linux.ibm.com> Reviewed-by: Leonardo Bras <leonardo@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200227134715.9715-1-desnesn@linux.ibm.com
-rw-r--r--arch/powerpc/kernel/cputable.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index e745abc5457a..245be4fafe13 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -2193,11 +2193,13 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset,
* oprofile_cpu_type already has a value, then we are
* possibly overriding a real PVR with a logical one,
* and, in that case, keep the current value for
- * oprofile_cpu_type.
+ * oprofile_cpu_type. Futhermore, let's ensure that the
+ * fix for the PMAO bug is enabled on compatibility mode.
*/
if (old.oprofile_cpu_type != NULL) {
t->oprofile_cpu_type = old.oprofile_cpu_type;
t->oprofile_type = old.oprofile_type;
+ t->cpu_features |= old.cpu_features & CPU_FTR_PMAO_BUG;
}
}