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| author | Ravi Bangoria <ravi.bangoria@linux.ibm.com> | 2019-05-11 08:12:17 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-11 12:22:41 +0200 |
| commit | 9cda7c0b07bd044a910533f8a9c8910de7d6cf58 (patch) | |
| tree | c75d8ebf0b871471836db2474c35d89ebbd9b7a7 /arch/powerpc/perf/power9-pmu.c | |
| parent | bb7804421b13a20e0bac2fbed0d26fcdcde17e21 (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")
Cc: stable@vger.kernel.org # v3.10+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/perf/power9-pmu.c')
| -rw-r--r-- | arch/powerpc/perf/power9-pmu.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c index 9abcd8f65504..c396d5e5098c 100644 --- a/arch/powerpc/perf/power9-pmu.c +++ b/arch/powerpc/perf/power9-pmu.c @@ -30,6 +30,7 @@ enum { #define POWER9_MMCRA_IFM1 0x0000000040000000UL #define POWER9_MMCRA_IFM2 0x0000000080000000UL #define POWER9_MMCRA_IFM3 0x00000000C0000000UL +#define POWER9_MMCRA_BHRB_MASK 0x00000000C0000000UL GENERIC_EVENT_ATTR(cpu-cycles, PM_CYC); GENERIC_EVENT_ATTR(stalled-cycles-frontend, PM_ICT_NOSLOT_CYC); @@ -177,6 +178,8 @@ static u64 power9_bhrb_filter_map(u64 branch_sample_type) static void power9_config_bhrb(u64 pmu_bhrb_filter) { + pmu_bhrb_filter &= POWER9_MMCRA_BHRB_MASK; + /* Enable BHRB filter in PMU */ mtspr(SPRN_MMCRA, (mfspr(SPRN_MMCRA) | pmu_bhrb_filter)); } |