drivers/perf: riscv: Add raw event v2 support

SBI v3.0 introduced a new raw event type that allows wider
mhpmeventX width to be programmed via CFG_MATCH.

Use the raw event v2 if SBI v3.0 is available.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Paul Walmsley <pjw@kernel.org>
Link: https://lore.kernel.org/r/20250909-pmu_event_info-v6-2-d8f80cacb884@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>

Author: atishp04

arch/riscv/include/asm/sbi.h

@@ -161,7 +161,10 @@ struct riscv_pmu_snapshot_data {
 
 #define RISCV_PMU_RAW_EVENT_MASK GENMASK_ULL(47, 0)
 #define RISCV_PMU_PLAT_FW_EVENT_MASK GENMASK_ULL(61, 0)
+/* SBI v3.0 allows extended hpmeventX width value */
+#define RISCV_PMU_RAW_EVENT_V2_MASK GENMASK_ULL(55, 0)
 #define RISCV_PMU_RAW_EVENT_IDX 0x20000
+#define RISCV_PMU_RAW_EVENT_V2_IDX 0x30000
 #define RISCV_PLAT_FW_EVENT	0xFFFF
 
 /** General pmu event codes specified in SBI PMU extension */
@@ -219,6 +222,7 @@ enum sbi_pmu_event_type {
 	SBI_PMU_EVENT_TYPE_HW = 0x0,
 	SBI_PMU_EVENT_TYPE_CACHE = 0x1,
 	SBI_PMU_EVENT_TYPE_RAW = 0x2,
+	SBI_PMU_EVENT_TYPE_RAW_V2 = 0x3,
 	SBI_PMU_EVENT_TYPE_FW = 0xf,
 };
 

drivers/perf/riscv_pmu_sbi.c

@@ -59,7 +59,7 @@ asm volatile(ALTERNATIVE(						\
 #define PERF_EVENT_FLAG_USER_ACCESS	BIT(SYSCTL_USER_ACCESS)
 #define PERF_EVENT_FLAG_LEGACY		BIT(SYSCTL_LEGACY)
 
-PMU_FORMAT_ATTR(event, "config:0-47");
+PMU_FORMAT_ATTR(event, "config:0-55");
 PMU_FORMAT_ATTR(firmware, "config:62-63");
 
 static bool sbi_v2_available;
@@ -527,8 +527,10 @@ static int pmu_sbi_event_map(struct perf_event *event, u64 *econfig)
 		break;
 	case PERF_TYPE_RAW:
 		/*
-		 * As per SBI specification, the upper 16 bits must be unused
-		 * for a hardware raw event.
+		 * As per SBI v0.3 specification,
+		 *  -- the upper 16 bits must be unused for a hardware raw event.
+		 * As per SBI v2.0 specification,
+		 *  -- the upper 8 bits must be unused for a hardware raw event.
 		 * Bits 63:62 are used to distinguish between raw events
 		 * 00 - Hardware raw event
 		 * 10 - SBI firmware events
@@ -537,8 +539,12 @@ static int pmu_sbi_event_map(struct perf_event *event, u64 *econfig)
 
 		switch (config >> 62) {
 		case 0:
-			/* Return error any bits [48-63] is set  as it is not allowed by the spec */
-			if (!(config & ~RISCV_PMU_RAW_EVENT_MASK)) {
+			if (sbi_v3_available) {
+				if (!(config & ~RISCV_PMU_RAW_EVENT_V2_MASK)) {
+					*econfig = config & RISCV_PMU_RAW_EVENT_V2_MASK;
+					ret = RISCV_PMU_RAW_EVENT_V2_IDX;
+				}
+			} else if (!(config & ~RISCV_PMU_RAW_EVENT_MASK)) {
 				*econfig = config & RISCV_PMU_RAW_EVENT_MASK;
 				ret = RISCV_PMU_RAW_EVENT_IDX;
 			}