diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2014-07-23 17:20:04 +1000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-07-23 17:16:47 +1000 |
| commit | 8903461c9bc56fcb041fb92d054e2529951770b6 (patch) | |
| tree | 56c803836b9612a4e0cf25471df04621a4307cbd | |
| parent | 6f5405bc2ee0102bb3856e2cdea64ff415db2e0c (diff) | |
powerpc/perf: Fix MMCR2 handling for EBB
In the recent commit b50a6c584bb4 "Clear MMCR2 when enabling PMU", I
screwed up the handling of MMCR2 for tasks using EBB.
We must make sure we set MMCR2 *before* ebb_switch_in(), otherwise we
overwrite the value of MMCR2 that userspace may have written. That
potentially breaks a task that uses EBB and manually uses MMCR2 for
event freezing.
Fixes: b50a6c584bb4 ("powerpc/perf: Clear MMCR2 when enabling PMU")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/perf/core-book3s.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 6b0641c3f03..fe52db2eea6 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1307,6 +1307,9 @@ static void power_pmu_enable(struct pmu *pmu) out_enable: pmao_restore_workaround(ebb); + if (ppmu->flags & PPMU_ARCH_207S) + mtspr(SPRN_MMCR2, 0); + mmcr0 = ebb_switch_in(ebb, cpuhw->mmcr[0]); mb(); @@ -1315,9 +1318,6 @@ static void power_pmu_enable(struct pmu *pmu) write_mmcr0(cpuhw, mmcr0); - if (ppmu->flags & PPMU_ARCH_207S) - mtspr(SPRN_MMCR2, 0); - /* * Enable instruction sampling if necessary */ |