From: Nicholas Piggin npiggin@gmail.com
stable inclusion from stable-v6.6.3 commit 63fe567a0668a893e8bb16faa8624e8c99c2dbd2 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit ea142e590aec55ba40c5affb4d49e68c713c63dc upstream.
When the PMU is disabled, MMCRA is not updated to disable BHRB and instruction sampling. This can lead to those features remaining enabled, which can slow down a real or emulated CPU.
Fixes: 1cade527f6e9 ("powerpc/perf: BHRB control to disable BHRB logic when not used") Cc: stable@vger.kernel.org # v5.9+ Signed-off-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://msgid.link/20231018153423.298373-1-npiggin@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/powerpc/perf/core-book3s.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 8c1f7def596e..10b946e9c6e7 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1371,8 +1371,7 @@ static void power_pmu_disable(struct pmu *pmu) /* * Disable instruction sampling if it was enabled */ - if (cpuhw->mmcr.mmcra & MMCRA_SAMPLE_ENABLE) - val &= ~MMCRA_SAMPLE_ENABLE; + val &= ~MMCRA_SAMPLE_ENABLE;
/* Disable BHRB via mmcra (BHRBRD) for p10 */ if (ppmu->flags & PPMU_ARCH_31) @@ -1383,7 +1382,7 @@ static void power_pmu_disable(struct pmu *pmu) * instruction sampling or BHRB. */ if (val != mmcra) { - mtspr(SPRN_MMCRA, mmcra); + mtspr(SPRN_MMCRA, val); mb(); isync(); }