From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
linux-perf-users@vger.kernel.org
Subject: [RFC V1 08/11] arm64/perf: Enable branch stack sampling
Date: Mon, 24 Jan 2022 10:00:50 +0530 [thread overview]
Message-ID: <1642998653-21377-9-git-send-email-anshuman.khandual@arm.com> (raw)
In-Reply-To: <1642998653-21377-1-git-send-email-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 | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 0800c8858ed8..2117bf5d3232 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -537,9 +537,28 @@ 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;
+ }
+
+ /*
+ * 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
next prev parent reply other threads:[~2022-01-24 4:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 4:30 [RFC V1 00/11] arm64/perf: Enable branch stack sampling Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 01/11] perf: Consolidate branch sample filter helpers Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 02/11] arm64/perf: Add register definitions for BRBE Anshuman Khandual
2022-01-24 14:05 ` Marc Zyngier
2022-01-25 5:04 ` Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 03/11] arm64/perf: Update struct arm_pmu " Anshuman Khandual
2022-01-26 16:59 ` Rob Herring
2022-01-28 3:38 ` Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 04/11] arm64/perf: Update struct pmu_hw_events " Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 05/11] arm64/perf: Detect support " Anshuman Khandual
2022-01-26 17:18 ` Rob Herring
2022-01-28 3:27 ` Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 06/11] arm64/perf: Drive BRBE from perf event states Anshuman Khandual
2022-01-26 17:07 ` Rob Herring
2022-01-27 12:20 ` Anshuman Khandual
2022-01-27 14:31 ` Rob Herring
2022-01-24 4:30 ` [RFC V1 07/11] arm64/perf: Add BRBE driver Anshuman Khandual
2022-01-24 18:11 ` James Clark
2022-01-24 18:15 ` James Clark
2022-01-24 4:30 ` Anshuman Khandual [this message]
2022-01-24 18:02 ` [RFC V1 08/11] arm64/perf: Enable branch stack sampling James Clark
2022-01-24 4:30 ` [RFC V1 09/11] perf: Add more generic branch types Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 10/11] perf: Expand perf_branch_entry.type Anshuman Khandual
2022-01-25 16:58 ` James Clark
2022-01-28 4:14 ` Anshuman Khandual
2022-01-26 16:47 ` Rob Herring
2022-01-27 10:41 ` Anshuman Khandual
2022-01-24 4:30 ` [RFC V1 11/11] perf: Capture branch privilege information Anshuman Khandual
2022-01-25 15:39 ` James Clark
2022-02-02 11:11 ` Anshuman Khandual
2022-01-26 17:27 ` James Clark
2022-03-14 6:47 ` Anshuman Khandual
2022-01-25 16:25 ` [PATCH 0/1] perf test: Add branch stack sampling tests for ARM64 German Gomez
2022-01-25 16:25 ` [PATCH 1/1] " German Gomez
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