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authorMichael Ellerman <mpe@ellerman.id.au>2014-07-23 11:20:04 +0400
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-07-23 11:16:47 +0400
commit8903461c9bc56fcb041fb92d054e2529951770b6 (patch)
tree56c803836b9612a4e0cf25471df04621a4307cbd /arch
parent6f5405bc2ee0102bb3856e2cdea64ff415db2e0c (diff)
downloadlinux-8903461c9bc56fcb041fb92d054e2529951770b6.tar.xz
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/perf/core-book3s.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 6b0641c3f03f..fe52db2eea6a 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
*/