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| author | Ravi Bangoria <ravi.bangoria@linux.ibm.com> | 2019-05-11 08:12:17 +0530 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-10-05 16:19:41 +0100 |
| commit | 19101a7d64caba559aba5573aa7b78576a82780c (patch) | |
| tree | 3daa8eefaaf36fe7c76589c344e9127430280c8a /arch/powerpc/perf/power8-pmu.c | |
| parent | 7beaf6ee32a3b1298db6db81cf8983588d2f7366 (diff) | |
powerpc/perf: Fix MMCRA corruption by bhrb_filter
commit 3202e35ec1c8fc19cea24253ff83edf702a60a02 upstream.
Consider a scenario where user creates two events:
1st event:
attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY;
fd = perf_event_open(attr, 0, 1, -1, 0);
This sets cpuhw->bhrb_filter to 0 and returns valid fd.
2nd event:
attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
attr.branch_sample_type = PERF_SAMPLE_BRANCH_CALL;
fd = perf_event_open(attr, 0, 1, -1, 0);
It overrides cpuhw->bhrb_filter to -1 and returns with error.
Now if power_pmu_enable() gets called by any path other than
power_pmu_add(), ppmu->config_bhrb(-1) will set MMCRA to -1.
Fixes: 3925f46bb590 ("powerpc/perf: Enable branch stack sampling framework")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[bwh: Backported to 3.16: drop changes in power9-pmu.c]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/powerpc/perf/power8-pmu.c')
| -rw-r--r-- | arch/powerpc/perf/power8-pmu.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c index fc6b5282bce1..71e630d9558b 100644 --- a/arch/powerpc/perf/power8-pmu.c +++ b/arch/powerpc/perf/power8-pmu.c @@ -175,6 +175,7 @@ #define POWER8_MMCRA_IFM1 0x0000000040000000UL #define POWER8_MMCRA_IFM2 0x0000000080000000UL #define POWER8_MMCRA_IFM3 0x00000000C0000000UL +#define POWER8_MMCRA_BHRB_MASK 0x00000000C0000000UL #define ONLY_PLM \ (PERF_SAMPLE_BRANCH_USER |\ @@ -666,6 +667,8 @@ static u64 power8_bhrb_filter_map(u64 branch_sample_type) static void power8_config_bhrb(u64 pmu_bhrb_filter) { + pmu_bhrb_filter &= POWER8_MMCRA_BHRB_MASK; + /* Enable BHRB filter in PMU */ mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter)); } |