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From: "Desnes A. Nunes do Rosario" <desnesn@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: desnesn@linux.ibm.com, gromero@linux.ibm.com
Subject: [PATCH] powerpc: fix hardware PMU exception bug on PowerVM compatibility mode systems
Date: Thu, 13 Feb 2020 21:19:05 -0300	[thread overview]
Message-ID: <20200214001905.20065-1-desnesn@linux.ibm.com> (raw)

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>
---
 arch/powerpc/kernel/cputable.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index e745abc5457a..5bfef6263dfb 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -2198,6 +2198,8 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset,
 		if (old.oprofile_cpu_type != NULL) {
 			t->oprofile_cpu_type = old.oprofile_cpu_type;
 			t->oprofile_type = old.oprofile_type;
+			if (old.cpu_features & CPU_FTR_PMAO_BUG)
+				t->cpu_features |= CPU_FTR_PMAO_BUG;
 		}
 	}
 
-- 
2.21.1


             reply	other threads:[~2020-02-14  0:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14  0:19 Desnes A. Nunes do Rosario [this message]
2020-02-15  6:26 ` [PATCH] powerpc: fix hardware PMU exception bug on PowerVM compatibility mode systems Leonardo Bras
2020-02-15  5:39 Leonardo Bras
2020-02-27 13:29 ` Desnes Augusto Nunes do Rosario

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