From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, peterz@infradead.org,
acme@kernel.org, mark.rutland@arm.com, will@kernel.org,
catalin.marinas@arm.com
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Subject: [PATCH V3 7/7] arm64/perf: Enable branch stack sampling
Date: Thu, 29 Sep 2022 13:28:57 +0530 [thread overview]
Message-ID: <20220929075857.158358-8-anshuman.khandual@arm.com> (raw)
In-Reply-To: <20220929075857.158358-1-anshuman.khandual@arm.com>
Now that all the required pieces are already in place, just enable the perf
branch stack sampling support on arm64 platform, by removing the gate which
blocks it in armpmu_event_init().
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
drivers/perf/arm_pmu.c | 32 +++++++++++++++++++++++++++++---
1 file changed, 29 insertions(+), 3 deletions(-)
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 93b36933124f..2a9b988b53c2 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -537,9 +537,35 @@ static int armpmu_event_init(struct perf_event *event)
!cpumask_test_cpu(event->cpu, &armpmu->supported_cpus))
return -ENOENT;
- /* does not support taken branch sampling */
- if (has_branch_stack(event))
- return -EOPNOTSUPP;
+ if (has_branch_stack(event)) {
+ /*
+ * BRBE support is absent. Select CONFIG_ARM_BRBE_PMU
+ * in the config, before branch stack sampling events
+ * can be requested.
+ */
+ if (!IS_ENABLED(CONFIG_ARM_BRBE_PMU)) {
+ pr_warn_once("BRBE is disabled, select CONFIG_ARM_BRBE_PMU\n");
+ return -EOPNOTSUPP;
+ }
+
+ if (event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_KERNEL) {
+ if (!perfmon_capable()) {
+ pr_warn_once("does not have permission for kernel branch filter\n");
+ return -EPERM;
+ }
+ }
+
+ /*
+ * Branch stack sampling event can not be supported in
+ * case either the required driver itself is absent or
+ * BRBE buffer, is not supported. Besides checking for
+ * the callback prevents a crash in case it's absent.
+ */
+ if (!armpmu->brbe_supported || !armpmu->brbe_supported(event)) {
+ pr_warn_once("BRBE is not supported\n");
+ return -EOPNOTSUPP;
+ }
+ }
if (armpmu->map_event(event) == -ENOENT)
return -ENOENT;
--
2.25.1
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next prev parent reply other threads:[~2022-09-29 8:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-29 7:58 [PATCH V3 0/7] arm64/perf: Enable branch stack sampling Anshuman Khandual
2022-09-29 7:58 ` [PATCH V3 1/7] arm64/perf: Add BRBE registers and fields Anshuman Khandual
2022-09-29 11:29 ` Mark Brown
2022-09-30 4:07 ` Anshuman Khandual
2022-09-29 7:58 ` [PATCH V3 2/7] arm64/perf: Update struct arm_pmu for BRBE Anshuman Khandual
2022-09-29 7:58 ` [PATCH V3 3/7] arm64/perf: Update struct pmu_hw_events " Anshuman Khandual
2022-09-29 7:58 ` [PATCH V3 4/7] driver/perf/arm_pmu_platform: Add support for BRBE attributes detection Anshuman Khandual
2022-10-06 13:37 ` James Clark
2022-10-10 14:17 ` James Clark
2022-10-11 9:21 ` Anshuman Khandual
2022-10-12 7:50 ` Anshuman Khandual
2022-10-11 9:16 ` Anshuman Khandual
2022-09-29 7:58 ` [PATCH V3 5/7] arm64/perf: Drive BRBE from perf event states Anshuman Khandual
2022-09-29 7:58 ` [PATCH V3 6/7] arm64/perf: Add BRBE driver Anshuman Khandual
2022-09-29 7:58 ` Anshuman Khandual [this message]
2022-10-10 13:55 ` [PATCH V3 7/7] arm64/perf: Enable branch stack sampling James Clark
2022-10-10 15:48 ` Suzuki K Poulose
2022-10-11 9:27 ` Anshuman Khandual
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