From ee95b88d71b9cf7ac1085ebc014f161971e1be9a Mon Sep 17 00:00:00 2001
From: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>
Date: Fri, 5 May 2023 07:20:57 +0000
Subject: [PATCH] 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 <v.v.mitrofanov@yadro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20230505072058.1049732-1-v.v.mitrofanov@yadro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
drivers/perf/riscv_pmu_sbi.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 0bc491252a44c..4163ff5174715 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;
--
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