linux-kernel - [PATCH v7 09/24] drivers/perf: riscv: Fix counter mask iteration for RV32

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Message-Id: <20240416184421.3693802-10-atishp@rivosinc.com>
Date: Tue, 16 Apr 2024 11:44:06 -0700
From: Atish Patra <atishp@...osinc.com>
To: linux-kernel@...r.kernel.org
Cc: Atish Patra <atishp@...osinc.com>,
	Andrew Jones <ajones@...tanamicro.com>,
	Ajay Kaher <ajay.kaher@...adcom.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Alexandre Ghiti <alexghiti@...osinc.com>,
	Anup Patel <anup@...infault.org>,
	Conor Dooley <conor.dooley@...rochip.com>,
	Juergen Gross <jgross@...e.com>,
	kvm-riscv@...ts.infradead.org,
	kvm@...r.kernel.org,
	linux-kselftest@...r.kernel.org,
	linux-riscv@...ts.infradead.org,
	Mark Rutland <mark.rutland@....com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Paul Walmsley <paul.walmsley@...ive.com>,
	Shuah Khan <shuah@...nel.org>,
	virtualization@...ts.linux.dev,
	Will Deacon <will@...nel.org>,
	x86@...nel.org
Subject: [PATCH v7 09/24] drivers/perf: riscv: Fix counter mask iteration for RV32

For RV32, used_hw_ctrs can have more than 1 word if the firmware chooses
to interleave firmware/hardware counters indicies. Even though it's a
unlikely scenario, handle that case by iterating over all the words
instead of just using the first word.

Reviewed-by: Andrew Jones <ajones@...tanamicro.com>
Signed-off-by: Atish Patra <atishp@...osinc.com>
---
 drivers/perf/riscv_pmu_sbi.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index dabf8a17b096..60bcd52f6da9 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -772,13 +772,15 @@ static inline void pmu_sbi_stop_hw_ctrs(struct riscv_pmu *pmu)
 {
 	struct cpu_hw_events *cpu_hw_evt = this_cpu_ptr(pmu->hw_events);
 	unsigned long flag = 0;
+	int i;
 
 	if (sbi_pmu_snapshot_available())
 		flag = SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT;
 
-	/* No need to check the error here as we can't do anything about the error */
-	sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, 0,
-		  cpu_hw_evt->used_hw_ctrs[0], flag, 0, 0, 0);
+	for (i = 0; i < BITS_TO_LONGS(RISCV_MAX_COUNTERS); i++)
+		/* No need to check the error here as we can't do anything about the error */
+		sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, i * BITS_PER_LONG,
+			  cpu_hw_evt->used_hw_ctrs[i], flag, 0, 0, 0);
 }
 
 /*
@@ -790,7 +792,7 @@ static inline void pmu_sbi_stop_hw_ctrs(struct riscv_pmu *pmu)
 static noinline void pmu_sbi_start_ovf_ctrs_sbi(struct cpu_hw_events *cpu_hw_evt,
 						unsigned long ctr_ovf_mask)
 {
-	int idx = 0;
+	int idx = 0, i;
 	struct perf_event *event;
 	unsigned long flag = SBI_PMU_START_FLAG_SET_INIT_VALUE;
 	unsigned long ctr_start_mask = 0;
@@ -798,11 +800,12 @@ static noinline void pmu_sbi_start_ovf_ctrs_sbi(struct cpu_hw_events *cpu_hw_evt
 	struct hw_perf_event *hwc;
 	u64 init_val = 0;
 
-	ctr_start_mask = cpu_hw_evt->used_hw_ctrs[0] & ~ctr_ovf_mask;
-
-	/* Start all the counters that did not overflow in a single shot */
-	sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, 0, ctr_start_mask,
-		  0, 0, 0, 0);
+	for (i = 0; i < BITS_TO_LONGS(RISCV_MAX_COUNTERS); i++) {
+		ctr_start_mask = cpu_hw_evt->used_hw_ctrs[i] & ~ctr_ovf_mask;
+		/* Start all the counters that did not overflow in a single shot */
+		sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG, ctr_start_mask,
+			0, 0, 0, 0);
+	}
 
 	/* Reinitialize and start all the counter that overflowed */
 	while (ctr_ovf_mask) {
-- 
2.34.1