On 11/05/19 8:12 AM, Ravi Bangoria wrote:
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.
Reviewed-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bango...@linux.ibm.com> --- arch/powerpc/perf/core-book3s.c | 6 ++++-- arch/powerpc/perf/power8-pmu.c | 3 +++ arch/powerpc/perf/power9-pmu.c | 3 +++ 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index b0723002a396..8eb5dc5df62b 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1846,6 +1846,7 @@ static int power_pmu_event_init(struct perf_event *event) int n; int err; struct cpu_hw_events *cpuhw; + u64 bhrb_filter; if (!ppmu) return -ENOENT; @@ -1951,13 +1952,14 @@ static int power_pmu_event_init(struct perf_event *event) err = power_check_constraints(cpuhw, events, cflags, n + 1); if (has_branch_stack(event)) { - cpuhw->bhrb_filter = ppmu->bhrb_filter_map( + bhrb_filter = ppmu->bhrb_filter_map( event->attr.branch_sample_type); - if (cpuhw->bhrb_filter == -1) { + if (bhrb_filter == -1) { put_cpu_var(cpu_hw_events); return -EOPNOTSUPP; } + cpuhw->bhrb_filter = bhrb_filter; } put_cpu_var(cpu_hw_events); diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c index d12a2db26353..d10feef93b6b 100644 --- a/arch/powerpc/perf/power8-pmu.c +++ b/arch/powerpc/perf/power8-pmu.c @@ -29,6 +29,7 @@ enum { #define POWER8_MMCRA_IFM1 0x0000000040000000UL #define POWER8_MMCRA_IFM2 0x0000000080000000UL #define POWER8_MMCRA_IFM3 0x00000000C0000000UL +#define POWER8_MMCRA_BHRB_MASK 0x00000000C0000000UL /* * Raw event encoding for PowerISA v2.07 (Power8): @@ -243,6 +244,8 @@ 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)); } diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c index 030544e35959..f3987915cadc 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)); }