From ee95b88d71b9cf7ac1085ebc014f161971e1be9a Mon Sep 17 00:00:00 2001 From: Viacheslav Mitrofanov Date: Fri, 5 May 2023 07:20:57 +0000 Subject: perf: RISC-V: Limit the number of counters returned from SBI Perf gets the number of supported counters from SBI. If it happens that the number of returned counters more than RISCV_MAX_COUNTERS the code trusts it. It does not lead to an immediate problem but can potentially lead to it. Prevent getting more than RISCV_MAX_COUNTERS from SBI. Signed-off-by: Viacheslav Mitrofanov Reviewed-by: Andrew Jones Reviewed-by: Atish Patra Link: https://lore.kernel.org/r/20230505072058.1049732-1-v.v.mitrofanov@yadro.com Signed-off-by: Palmer Dabbelt --- drivers/perf/riscv_pmu_sbi.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/perf') diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c index 0bc491252a44..4163ff517471 100644 --- a/drivers/perf/riscv_pmu_sbi.c +++ b/drivers/perf/riscv_pmu_sbi.c @@ -855,6 +855,12 @@ static int pmu_sbi_device_probe(struct platform_device *pdev) goto out_free; } + /* It is possible to get from SBI more than max number of counters */ + if (num_counters > RISCV_MAX_COUNTERS) { + num_counters = RISCV_MAX_COUNTERS; + pr_info("SBI returned more than maximum number of counters. Limiting the number of counters to %d\n", num_counters); + } + /* cache all the information about counters now */ if (pmu_sbi_get_ctrinfo(num_counters, &cmask)) goto out_free; -- cgit v1.2.3