[PATCH] perf: riscv: Fix counter_idx_base in PMU snapshot restart

[liutong]

In pmu_sbi_start_ovf_ctrs_snapshot(), after for_each_set_bit() finishes
iterating used_hw_ctrs[i], idx is left at BITS_PER_LONG. The subsequent
sbi_ecall() uses idx * BITS_PER_LONG as counter_idx_base, passing an
out-of-range value (4096 on 64-bit) to SBI_EXT_PMU_COUNTER_START.

This causes the firmware to reject the call and overflowed counters are
never restarted.

Use the outer loop index 'i' instead of the exhausted iterator 'idx'.

Fixes: a8625217a054 ("drivers/perf: riscv: Implement SBI PMU snapshot function")
Signed-off-by: liutong <liutong@xxxxxxxxxxx>
---
 drivers/perf/riscv_pmu_sbi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index dfc886dee..099ba974a 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1021,7 +1021,7 @@ static inline void pmu_sbi_start_ovf_ctrs_snapshot(struct cpu_hw_events *cpu_hw_
 			sdata->ctr_values[idx] =
 					cpu_hw_evt->snapshot_cval_shcopy[idx + i * BITS_PER_LONG];
 		/* Start all the counters in a single shot */
-		sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, idx * BITS_PER_LONG,
+		sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG,
 			  cpu_hw_evt->used_hw_ctrs[i], flag, 0, 0, 0);
 	}
 }
-- 
2.34.1