| Message ID | 20231018153423.298373-1-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ea142e590aec55ba40c5affb4d49e68c713c63dc |
| Headers | show |
| Series | powerpc/perf: Fix disabling BHRB and instruction sampling | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/github-powerpc_ppctests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_selftests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_sparse | success | Successfully ran 4 jobs. |
| snowpatch_ozlabs/github-powerpc_clang | success | Successfully ran 6 jobs. |
| snowpatch_ozlabs/github-powerpc_kernel_qemu | success | Successfully ran 23 jobs. |
On Thu, 19 Oct 2023 01:34:23 +1000, Nicholas Piggin wrote: > 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. > > Applied to powerpc/next. [1/1] powerpc/perf: Fix disabling BHRB and instruction sampling https://git.kernel.org/powerpc/c/ea142e590aec55ba40c5affb4d49e68c713c63dc cheers
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(); }
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") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/perf/core-book3s.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)