[v2,15/21] RISC-V: perf: Skip PMU SBI extension when not implemented

Commit Message

Atish Patra Jan. 14, 2025, 10:57 p.m. UTC

From: Charlie Jenkins <[e-mail]>

When the PMU SBI extension is not implemented, sbi_v2_available should
not be set to true. The SBI implementation for counter config matching
and firmware counter read  should also be skipped when the SBI extension
is not implemented.

Signed-off-by: Atish Patra <[e-mail]>
Signed-off-by: Charlie Jenkins <[e-mail]>
---
 drivers/perf/riscv_pmu_dev.c | 46 ++++++++++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 19 deletions(-)

Patch

diff --git a/drivers/perf/riscv_pmu_dev.c b/drivers/perf/riscv_pmu_dev.c
index c80f8ef79204..83e7d1f6b016 100644
--- a/drivers/perf/riscv_pmu_dev.c
+++ b/drivers/perf/riscv_pmu_dev.c
@@ -410,18 +410,22 @@  static void rvpmu_sbi_check_event(struct sbi_pmu_event_data *edata)
 	}
 }
 
-static void rvpmu_sbi_check_std_events(struct work_struct *work)
+static void rvpmu_check_std_events(struct work_struct *work)
 {
-	for (int i = 0; i < ARRAY_SIZE(pmu_hw_event_map); i++)
-		rvpmu_sbi_check_event(&pmu_hw_event_map[i]);
-
-	for (int i = 0; i < ARRAY_SIZE(pmu_cache_event_map); i++)
-		for (int j = 0; j < ARRAY_SIZE(pmu_cache_event_map[i]); j++)
-			for (int k = 0; k < ARRAY_SIZE(pmu_cache_event_map[i][j]); k++)
-				rvpmu_sbi_check_event(&pmu_cache_event_map[i][j][k]);
+	if (riscv_pmu_sbi_available()) {
+		for (int i = 0; i < ARRAY_SIZE(pmu_hw_event_sbi_map); i++)
+			rvpmu_sbi_check_event(&pmu_hw_event_sbi_map[i]);
+
+		for (int i = 0; i < ARRAY_SIZE(pmu_cache_event_sbi_map); i++)
+			for (int j = 0; j < ARRAY_SIZE(pmu_cache_event_sbi_map[i]); j++)
+				for (int k = 0; k < ARRAY_SIZE(pmu_cache_event_sbi_map[i][j]); k++)
+					rvpmu_sbi_check_event(&pmu_cache_event_sbi_map[i][j][k]);
+	} else {
+		DO_ONCE_LITE_IF(1, pr_err, "Boot time config matching not required for smcdeleg\n");
+	}
 }
 
-static DECLARE_WORK(check_std_events_work, rvpmu_sbi_check_std_events);
+static DECLARE_WORK(check_std_events_work, rvpmu_check_std_events);
 
 static ssize_t rvpmu_format_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
@@ -549,6 +553,9 @@  static int rvpmu_sbi_ctr_get_idx(struct perf_event *event)
 
 	cflags = rvpmu_sbi_get_filter_flags(event);
 
+	if (!riscv_pmu_sbi_available())
+		return -ENOENT;
+
 	/*
 	 * In legacy mode, we have to force the fixed counters for those events
 	 * but not in the user access mode as we want to use the other counters
@@ -562,10 +569,9 @@  static int rvpmu_sbi_ctr_get_idx(struct perf_event *event)
 			cflags |= SBI_PMU_CFG_FLAG_SKIP_MATCH;
 			ctr_mask = BIT(CSR_INSTRET - CSR_CYCLE);
 		}
-	}
-
-	if (pmu_sbi_is_fw_event(event) && cdeleg_available)
+	} else if (pmu_sbi_is_fw_event(event) && cdeleg_available) {
 		ctr_mask = firmware_cmask;
+	}
 
 	/* retrieve the available counter index */
 #if defined(CONFIG_32BIT)
@@ -871,7 +877,7 @@  static u64 rvpmu_ctr_read(struct perf_event *event)
 		return val;
 	}
 
-	if (pmu_sbi_is_fw_event(event)) {
+	if (pmu_sbi_is_fw_event(event) && riscv_pmu_sbi_available()) {
 		ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ,
 				hwc->idx, 0, 0, 0, 0, 0);
 		if (ret.error)
@@ -1952,14 +1958,16 @@  static int __init rvpmu_devinit(void)
 	int ret;
 	struct platform_device *pdev;
 
-	if (sbi_spec_version >= sbi_mk_version(0, 3) &&
-	    sbi_probe_extension(SBI_EXT_PMU)) {
-		static_branch_enable(&riscv_pmu_sbi_available);
-		sbi_available = true;
+	if (sbi_probe_extension(SBI_EXT_PMU)) {
+		if (sbi_spec_version >= sbi_mk_version(0, 3)) {
+			static_branch_enable(&riscv_pmu_sbi_available);
+			sbi_available = true;
+		}
+
+		if (sbi_spec_version >= sbi_mk_version(2, 0))
+			sbi_v2_available = true;
 	}
 
-	if (sbi_spec_version >= sbi_mk_version(2, 0))
-		sbi_v2_available = true;
 	/*
 	 * We need all three extensions to be present to access the counters
 	 * in S-mode via Supervisor Counter delegation.