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

[Sergey Matyukevich]

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 at 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