drivers/perf: riscv: handle legacy fallback in event check

[PATCH] drivers/perf: riscv: handle legacy fallback in event check

Sergey Matyukevich posted 1 patch 2 weeks, 1 day ago

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drivers/perf/riscv_pmu_sbi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

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[PATCH] drivers/perf: riscv: handle legacy fallback in event check

Posted by Sergey Matyukevich 2 weeks, 1 day ago

Common events PERF_COUNT_HW_CPU_CYCLES and PERF_COUNT_HW_INSTRUCTIONS
can fall back to the legacy counters. So do not mark them as invalid
if OpenSBI reports that they are not mapped to sampling counters
in PMU DT node.

Signed-off-by: Sergey Matyukevich <geomatsi@gmail.com>
---
 drivers/perf/riscv_pmu_sbi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index dfc886dee5ad..8f7aa71dc96f 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -335,7 +335,8 @@ static int pmu_sbi_check_event_info(void)
 		goto free_mem;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(pmu_hw_event_map); i++) {
+	/* skip check for cycles and instructions as they can fall back to legacy counters */
+	for (i = 2; i < ARRAY_SIZE(pmu_hw_event_map); i++) {
 		if (!(event_info_shmem[i].output & RISCV_PMU_EVENT_INFO_OUTPUT_MASK))
 			pmu_hw_event_map[i].event_idx = -ENOENT;
 	}

base-commit: a635d6748234582ea287c5ffeae28b9b23f91c7e
-- 
2.54.0