[PATCH v6 06/10] drivers: perf: Implement perf event mmap support in the legacy backend
From: Alexandre Ghiti <hidden>
Date: 2023-08-02 08:10:14
Also in:
linux-doc, linux-perf-users, linux-riscv, lkml
Subsystem:
arm pmu profiling and debugging, risc-v pmu drivers, the rest · Maintainers:
Will Deacon, Mark Rutland, Atish Patra, Linus Torvalds
Implement the needed callbacks in the legacy driver so that we can directly access the counters through perf in userspace. Signed-off-by: Alexandre Ghiti <redacted> Reviewed-by: Andrew Jones <redacted> Reviewed-by: Atish Patra <redacted> --- drivers/perf/riscv_pmu_legacy.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c
index 6a000abc28bb..79fdd667922e 100644
--- a/drivers/perf/riscv_pmu_legacy.c
+++ b/drivers/perf/riscv_pmu_legacy.c@@ -71,6 +71,29 @@ static void pmu_legacy_ctr_start(struct perf_event *event, u64 ival) local64_set(&hwc->prev_count, initial_val); } +static uint8_t pmu_legacy_csr_index(struct perf_event *event) +{ + return event->hw.idx; +} + +static void pmu_legacy_event_mapped(struct perf_event *event, struct mm_struct *mm) +{ + if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES && + event->attr.config != PERF_COUNT_HW_INSTRUCTIONS) + return; + + event->hw.flags |= PERF_EVENT_FLAG_USER_READ_CNT; +} + +static void pmu_legacy_event_unmapped(struct perf_event *event, struct mm_struct *mm) +{ + if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES && + event->attr.config != PERF_COUNT_HW_INSTRUCTIONS) + return; + + event->hw.flags &= ~PERF_EVENT_FLAG_USER_READ_CNT; +} + /* * This is just a simple implementation to allow legacy implementations * compatible with new RISC-V PMU driver framework.
@@ -91,6 +114,9 @@ static void pmu_legacy_init(struct riscv_pmu *pmu) pmu->ctr_get_width = NULL; pmu->ctr_clear_idx = NULL; pmu->ctr_read = pmu_legacy_read_ctr; + pmu->event_mapped = pmu_legacy_event_mapped; + pmu->event_unmapped = pmu_legacy_event_unmapped; + pmu->csr_index = pmu_legacy_csr_index; perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW); }
--
2.39.2
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