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author | Ravi Bangoria <ravi.bangoria@linux.ibm.com> | 2019-05-11 05:42:17 +0300 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-05-22 14:38:20 +0300 |
commit | 3202e35ec1c8fc19cea24253ff83edf702a60a02 (patch) | |
tree | 07a2f0939c84526a9bc367cccb2b958c7e8b8550 /arch/powerpc/perf/power9-pmu.c | |
parent | b59bd3527fe3c1939340df558d7f9d568fc9f882 (diff) | |
download | linux-3202e35ec1c8fc19cea24253ff83edf702a60a02.tar.xz |
powerpc/perf: Fix MMCRA corruption by bhrb_filter
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>
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 3a31ac6f4805..e19c492bd6ec 100644 --- a/arch/powerpc/perf/power9-pmu.c +++ b/arch/powerpc/perf/power9-pmu.c @@ -92,6 +92,7 @@ enum { #define POWER9_MMCRA_IFM1 0x0000000040000000UL #define POWER9_MMCRA_IFM2 0x0000000080000000UL #define POWER9_MMCRA_IFM3 0x00000000C0000000UL +#define POWER9_MMCRA_BHRB_MASK 0x00000000C0000000UL /* Nasty Power9 specific hack */ #define PVR_POWER9_CUMULUS 0x00002000 @@ -300,6 +301,8 @@ 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)); } |