From f5bfa23f576fdcc8e0b7fbff44cf70bd69ff9bdb Mon Sep 17 00:00:00 2001
From: Atish Patra
Date: Fri, 18 Feb 2022 16:46:54 -0800
Subject: RISC-V: Add a perf core library for pmu drivers

Implement a perf core library that can support all the essential perf
features in future. It can also accommodate any type of PMU implementation
in future. Currently, both SBI based perf driver and legacy driver
implemented uses the library. Most of the common perf functionalities
are kept in this core library wile PMU specific driver can implement PMU
specific features. For example, the SBI specific functionality will be
implemented in the SBI specific driver.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 drivers/perf/Kconfig     |  10 ++
 drivers/perf/Makefile    |   1 +
 drivers/perf/riscv_pmu.c | 322 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 333 insertions(+)
 create mode 100644 drivers/perf/riscv_pmu.c

(limited to 'drivers')

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index e1a0c44bc686..dbc0e3f98be9 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -56,6 +56,16 @@ config ARM_PMU
 	  Say y if you want to use CPU performance monitors on ARM-based
 	  systems.
 
+config RISCV_PMU
+	depends on RISCV
+	bool "RISC-V PMU framework"
+	default y
+	help
+	  Say y if you want to use CPU performance monitors on RISCV-based
+	  systems. This provides the core PMU framework that abstracts common
+	  PMU functionalities in a core library so that different PMU drivers
+	  can reuse it.
+
 config ARM_PMU_ACPI
 	depends on ARM_PMU && ACPI
 	def_bool y
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index 2db5418d5b0a..09082dea154b 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_FSL_IMX8_DDR_PMU) += fsl_imx8_ddr_perf.o
 obj-$(CONFIG_HISI_PMU) += hisilicon/
 obj-$(CONFIG_QCOM_L2_PMU)	+= qcom_l2_pmu.o
 obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
+obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
 obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
 obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
 obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c
new file mode 100644
index 000000000000..590a5789c128
--- /dev/null
+++ b/drivers/perf/riscv_pmu.c
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V performance counter support.
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ *
+ * This implementation is based on old RISC-V perf and ARM perf event code
+ * which are in turn based on sparc64 and x86 code.
+ */
+
+#include <linux/cpumask.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+#include <linux/perf/riscv_pmu.h>
+#include <linux/printk.h>
+#include <linux/smp.h>
+
+static unsigned long csr_read_num(int csr_num)
+{
+#define switchcase_csr_read(__csr_num, __val)		{\
+	case __csr_num:					\
+		__val = csr_read(__csr_num);		\
+		break; }
+#define switchcase_csr_read_2(__csr_num, __val)		{\
+	switchcase_csr_read(__csr_num + 0, __val)	 \
+	switchcase_csr_read(__csr_num + 1, __val)}
+#define switchcase_csr_read_4(__csr_num, __val)		{\
+	switchcase_csr_read_2(__csr_num + 0, __val)	 \
+	switchcase_csr_read_2(__csr_num + 2, __val)}
+#define switchcase_csr_read_8(__csr_num, __val)		{\
+	switchcase_csr_read_4(__csr_num + 0, __val)	 \
+	switchcase_csr_read_4(__csr_num + 4, __val)}
+#define switchcase_csr_read_16(__csr_num, __val)	{\
+	switchcase_csr_read_8(__csr_num + 0, __val)	 \
+	switchcase_csr_read_8(__csr_num + 8, __val)}
+#define switchcase_csr_read_32(__csr_num, __val)	{\
+	switchcase_csr_read_16(__csr_num + 0, __val)	 \
+	switchcase_csr_read_16(__csr_num + 16, __val)}
+
+	unsigned long ret = 0;
+
+	switch (csr_num) {
+	switchcase_csr_read_32(CSR_CYCLE, ret)
+	switchcase_csr_read_32(CSR_CYCLEH, ret)
+	default :
+		break;
+	}
+
+	return ret;
+#undef switchcase_csr_read_32
+#undef switchcase_csr_read_16
+#undef switchcase_csr_read_8
+#undef switchcase_csr_read_4
+#undef switchcase_csr_read_2
+#undef switchcase_csr_read
+}
+
+/*
+ * Read the CSR of a corresponding counter.
+ */
+unsigned long riscv_pmu_ctr_read_csr(unsigned long csr)
+{
+	if (csr < CSR_CYCLE || csr > CSR_HPMCOUNTER31H ||
+	   (csr > CSR_HPMCOUNTER31 && csr < CSR_CYCLEH)) {
+		pr_err("Invalid performance counter csr %lx\n", csr);
+		return -EINVAL;
+	}
+
+	return csr_read_num(csr);
+}
+
+u64 riscv_pmu_ctr_get_width_mask(struct perf_event *event)
+{
+	int cwidth;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!rvpmu->ctr_get_width)
+	/**
+	 * If the pmu driver doesn't support counter width, set it to default
+	 * maximum allowed by the specification.
+	 */
+		cwidth = 63;
+	else {
+		if (hwc->idx == -1)
+			/* Handle init case where idx is not initialized yet */
+			cwidth = rvpmu->ctr_get_width(0);
+		else
+			cwidth = rvpmu->ctr_get_width(hwc->idx);
+	}
+
+	return GENMASK_ULL(cwidth, 0);
+}
+
+u64 riscv_pmu_event_update(struct perf_event *event)
+{
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	u64 prev_raw_count, new_raw_count;
+	unsigned long cmask;
+	u64 oldval, delta;
+
+	if (!rvpmu->ctr_read)
+		return 0;
+
+	cmask = riscv_pmu_ctr_get_width_mask(event);
+
+	do {
+		prev_raw_count = local64_read(&hwc->prev_count);
+		new_raw_count = rvpmu->ctr_read(event);
+		oldval = local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+					 new_raw_count);
+	} while (oldval != prev_raw_count);
+
+	delta = (new_raw_count - prev_raw_count) & cmask;
+	local64_add(delta, &event->count);
+	local64_sub(delta, &hwc->period_left);
+
+	return delta;
+}
+
+static void riscv_pmu_stop(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+
+	WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
+
+	if (!(hwc->state & PERF_HES_STOPPED)) {
+		if (rvpmu->ctr_stop) {
+			rvpmu->ctr_stop(event, 0);
+			hwc->state |= PERF_HES_STOPPED;
+		}
+		riscv_pmu_event_update(event);
+		hwc->state |= PERF_HES_UPTODATE;
+	}
+}
+
+int riscv_pmu_event_set_period(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	s64 left = local64_read(&hwc->period_left);
+	s64 period = hwc->sample_period;
+	int overflow = 0;
+	uint64_t max_period = riscv_pmu_ctr_get_width_mask(event);
+
+	if (unlikely(left <= -period)) {
+		left = period;
+		local64_set(&hwc->period_left, left);
+		hwc->last_period = period;
+		overflow = 1;
+	}
+
+	if (unlikely(left <= 0)) {
+		left += period;
+		local64_set(&hwc->period_left, left);
+		hwc->last_period = period;
+		overflow = 1;
+	}
+
+	/*
+	 * Limit the maximum period to prevent the counter value
+	 * from overtaking the one we are about to program. In
+	 * effect we are reducing max_period to account for
+	 * interrupt latency (and we are being very conservative).
+	 */
+	if (left > (max_period >> 1))
+		left = (max_period >> 1);
+
+	local64_set(&hwc->prev_count, (u64)-left);
+	perf_event_update_userpage(event);
+
+	return overflow;
+}
+
+static void riscv_pmu_start(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	uint64_t max_period = riscv_pmu_ctr_get_width_mask(event);
+	u64 init_val;
+
+	if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
+		return;
+
+	if (flags & PERF_EF_RELOAD)
+		WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
+
+	hwc->state = 0;
+	riscv_pmu_event_set_period(event);
+	init_val = local64_read(&hwc->prev_count) & max_period;
+	rvpmu->ctr_start(event, init_val);
+	perf_event_update_userpage(event);
+}
+
+static int riscv_pmu_add(struct perf_event *event, int flags)
+{
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx;
+
+	idx = rvpmu->ctr_get_idx(event);
+	if (idx < 0)
+		return idx;
+
+	hwc->idx = idx;
+	cpuc->events[idx] = event;
+	cpuc->n_events++;
+	hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+	if (flags & PERF_EF_START)
+		riscv_pmu_start(event, PERF_EF_RELOAD);
+
+	/* Propagate our changes to the userspace mapping. */
+	perf_event_update_userpage(event);
+
+	return 0;
+}
+
+static void riscv_pmu_del(struct perf_event *event, int flags)
+{
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+
+	riscv_pmu_stop(event, PERF_EF_UPDATE);
+	cpuc->events[hwc->idx] = NULL;
+	/* The firmware need to reset the counter mapping */
+	if (rvpmu->ctr_stop)
+		rvpmu->ctr_stop(event, RISCV_PMU_STOP_FLAG_RESET);
+	cpuc->n_events--;
+	if (rvpmu->ctr_clear_idx)
+		rvpmu->ctr_clear_idx(event);
+	perf_event_update_userpage(event);
+	hwc->idx = -1;
+}
+
+static void riscv_pmu_read(struct perf_event *event)
+{
+	riscv_pmu_event_update(event);
+}
+
+static int riscv_pmu_event_init(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	int mapped_event;
+	u64 event_config = 0;
+	uint64_t cmask;
+
+	hwc->flags = 0;
+	mapped_event = rvpmu->event_map(event, &event_config);
+	if (mapped_event < 0) {
+		pr_debug("event %x:%llx not supported\n", event->attr.type,
+			 event->attr.config);
+		return mapped_event;
+	}
+
+	/*
+	 * idx is set to -1 because the index of a general event should not be
+	 * decided until binding to some counter in pmu->add().
+	 * config will contain the information about counter CSR
+	 * the idx will contain the counter index
+	 */
+	hwc->config = event_config;
+	hwc->idx = -1;
+	hwc->event_base = mapped_event;
+
+	if (!is_sampling_event(event)) {
+		/*
+		 * For non-sampling runs, limit the sample_period to half
+		 * of the counter width. That way, the new counter value
+		 * is far less likely to overtake the previous one unless
+		 * you have some serious IRQ latency issues.
+		 */
+		cmask = riscv_pmu_ctr_get_width_mask(event);
+		hwc->sample_period  =  cmask >> 1;
+		hwc->last_period    = hwc->sample_period;
+		local64_set(&hwc->period_left, hwc->sample_period);
+	}
+
+	return 0;
+}
+
+struct riscv_pmu *riscv_pmu_alloc(void)
+{
+	struct riscv_pmu *pmu;
+	int cpuid, i;
+	struct cpu_hw_events *cpuc;
+
+	pmu = kzalloc(sizeof(*pmu), GFP_KERNEL);
+	if (!pmu)
+		goto out;
+
+	pmu->hw_events = alloc_percpu_gfp(struct cpu_hw_events, GFP_KERNEL);
+	if (!pmu->hw_events) {
+		pr_info("failed to allocate per-cpu PMU data.\n");
+		goto out_free_pmu;
+	}
+
+	for_each_possible_cpu(cpuid) {
+		cpuc = per_cpu_ptr(pmu->hw_events, cpuid);
+		cpuc->n_events = 0;
+		for (i = 0; i < RISCV_MAX_COUNTERS; i++)
+			cpuc->events[i] = NULL;
+	}
+	pmu->pmu = (struct pmu) {
+		.event_init	= riscv_pmu_event_init,
+		.add		= riscv_pmu_add,
+		.del		= riscv_pmu_del,
+		.start		= riscv_pmu_start,
+		.stop		= riscv_pmu_stop,
+		.read		= riscv_pmu_read,
+	};
+
+	return pmu;
+
+out_free_pmu:
+	kfree(pmu);
+out:
+	return NULL;
+}
-- 
cgit v1.2.3


From 9b3e150e310ee71d7bae1e31c38a300cfa5e951b Mon Sep 17 00:00:00 2001
From: Atish Patra
Date: Fri, 18 Feb 2022 16:46:55 -0800
Subject: RISC-V: Add a simple platform driver for RISC-V legacy perf

The old RISC-V perf implementation allowed counting of only
cycle/instruction counters using perf. Restore that feature by implementing
a simple platform driver under a separate config to provide backward
compatibility. Any existing software stack will continue to work as it is.
However, it provides an easy way out in future where we can remove the
legacy driver.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 drivers/perf/Kconfig            |  10 +++
 drivers/perf/Makefile           |   1 +
 drivers/perf/riscv_pmu_legacy.c | 142 ++++++++++++++++++++++++++++++++++++++++
 include/linux/perf/riscv_pmu.h  |   6 ++
 4 files changed, 159 insertions(+)
 create mode 100644 drivers/perf/riscv_pmu_legacy.c

(limited to 'drivers')

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index dbc0e3f98be9..386162ad858a 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -66,6 +66,16 @@ config RISCV_PMU
 	  PMU functionalities in a core library so that different PMU drivers
 	  can reuse it.
 
+config RISCV_PMU_LEGACY
+	depends on RISCV_PMU
+	bool "RISC-V legacy PMU implementation"
+	default y
+	help
+	  Say y if you want to use the legacy CPU performance monitor
+	  implementation on RISC-V based systems. This only allows counting
+	  of cycle/instruction counter and doesn't support counter overflow,
+	  or programmable counters. It will be removed in future.
+
 config ARM_PMU_ACPI
 	depends on ARM_PMU && ACPI
 	def_bool y
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index 09082dea154b..c3d3268d495b 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_HISI_PMU) += hisilicon/
 obj-$(CONFIG_QCOM_L2_PMU)	+= qcom_l2_pmu.o
 obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
 obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
+obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
 obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
 obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
 obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c
new file mode 100644
index 000000000000..342778782359
--- /dev/null
+++ b/drivers/perf/riscv_pmu_legacy.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V performance counter support.
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ *
+ * This implementation is based on old RISC-V perf and ARM perf event code
+ * which are in turn based on sparc64 and x86 code.
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/perf/riscv_pmu.h>
+#include <linux/platform_device.h>
+
+#define RISCV_PMU_LEGACY_CYCLE		0
+#define RISCV_PMU_LEGACY_INSTRET	1
+#define RISCV_PMU_LEGACY_NUM_CTR	2
+
+static bool pmu_init_done;
+
+static int pmu_legacy_ctr_get_idx(struct perf_event *event)
+{
+	struct perf_event_attr *attr = &event->attr;
+
+	if (event->attr.type != PERF_TYPE_HARDWARE)
+		return -EOPNOTSUPP;
+	if (attr->config == PERF_COUNT_HW_CPU_CYCLES)
+		return RISCV_PMU_LEGACY_CYCLE;
+	else if (attr->config == PERF_COUNT_HW_INSTRUCTIONS)
+		return RISCV_PMU_LEGACY_INSTRET;
+	else
+		return -EOPNOTSUPP;
+}
+
+/* For legacy config & counter index are same */
+static int pmu_legacy_event_map(struct perf_event *event, u64 *config)
+{
+	return pmu_legacy_ctr_get_idx(event);
+}
+
+static u64 pmu_legacy_read_ctr(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+	u64 val;
+
+	if (idx == RISCV_PMU_LEGACY_CYCLE) {
+		val = riscv_pmu_ctr_read_csr(CSR_CYCLE);
+		if (IS_ENABLED(CONFIG_32BIT))
+			val = (u64)riscv_pmu_ctr_read_csr(CSR_CYCLEH) << 32 | val;
+	} else if (idx == RISCV_PMU_LEGACY_INSTRET) {
+		val = riscv_pmu_ctr_read_csr(CSR_INSTRET);
+		if (IS_ENABLED(CONFIG_32BIT))
+			val = ((u64)riscv_pmu_ctr_read_csr(CSR_INSTRETH)) << 32 | val;
+	} else
+		return 0;
+
+	return val;
+}
+
+static void pmu_legacy_ctr_start(struct perf_event *event, u64 ival)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	u64 initial_val = pmu_legacy_read_ctr(event);
+
+	/**
+	 * The legacy method doesn't really have a start/stop method.
+	 * It also can not update the counter with a initial value.
+	 * But we still need to set the prev_count so that read() can compute
+	 * the delta. Just use the current counter value to set the prev_count.
+	 */
+	local64_set(&hwc->prev_count, initial_val);
+}
+
+/**
+ * This is just a simple implementation to allow legacy implementations
+ * compatible with new RISC-V PMU driver framework.
+ * This driver only allows reading two counters i.e CYCLE & INSTRET.
+ * However, it can not start or stop the counter. Thus, it is not very useful
+ * will be removed in future.
+ */
+static void pmu_legacy_init(struct riscv_pmu *pmu)
+{
+	pr_info("Legacy PMU implementation is available\n");
+
+	pmu->num_counters = RISCV_PMU_LEGACY_NUM_CTR;
+	pmu->ctr_start = pmu_legacy_ctr_start;
+	pmu->ctr_stop = NULL;
+	pmu->event_map = pmu_legacy_event_map;
+	pmu->ctr_get_idx = pmu_legacy_ctr_get_idx;
+	pmu->ctr_get_width = NULL;
+	pmu->ctr_clear_idx = NULL;
+	pmu->ctr_read = pmu_legacy_read_ctr;
+
+	perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
+}
+
+static int pmu_legacy_device_probe(struct platform_device *pdev)
+{
+	struct riscv_pmu *pmu = NULL;
+
+	pmu = riscv_pmu_alloc();
+	if (!pmu)
+		return -ENOMEM;
+	pmu_legacy_init(pmu);
+
+	return 0;
+}
+
+static struct platform_driver pmu_legacy_driver = {
+	.probe		= pmu_legacy_device_probe,
+	.driver		= {
+		.name	= RISCV_PMU_LEGACY_PDEV_NAME,
+	},
+};
+
+static int __init riscv_pmu_legacy_devinit(void)
+{
+	int ret;
+	struct platform_device *pdev;
+
+	if (likely(pmu_init_done))
+		return 0;
+
+	ret = platform_driver_register(&pmu_legacy_driver);
+	if (ret)
+		return ret;
+
+	pdev = platform_device_register_simple(RISCV_PMU_LEGACY_PDEV_NAME, -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		platform_driver_unregister(&pmu_legacy_driver);
+		return PTR_ERR(pdev);
+	}
+
+	return ret;
+}
+late_initcall(riscv_pmu_legacy_devinit);
+
+void riscv_pmu_legacy_skip_init(void)
+{
+	pmu_init_done = true;
+}
diff --git a/include/linux/perf/riscv_pmu.h b/include/linux/perf/riscv_pmu.h
index 0d8979765d79..9140c491fc54 100644
--- a/include/linux/perf/riscv_pmu.h
+++ b/include/linux/perf/riscv_pmu.h
@@ -22,6 +22,7 @@
 #define RISCV_MAX_COUNTERS	64
 #define RISCV_OP_UNSUPP		(-EOPNOTSUPP)
 #define RISCV_PMU_PDEV_NAME	"riscv-pmu"
+#define RISCV_PMU_LEGACY_PDEV_NAME	"riscv-pmu-legacy"
 
 #define RISCV_PMU_STOP_FLAG_RESET 1
 
@@ -58,6 +59,11 @@ unsigned long riscv_pmu_ctr_read_csr(unsigned long csr);
 int riscv_pmu_event_set_period(struct perf_event *event);
 uint64_t riscv_pmu_ctr_get_width_mask(struct perf_event *event);
 u64 riscv_pmu_event_update(struct perf_event *event);
+#ifdef CONFIG_RISCV_PMU_LEGACY
+void riscv_pmu_legacy_skip_init(void);
+#else
+static inline void riscv_pmu_legacy_skip_init(void) {};
+#endif
 struct riscv_pmu *riscv_pmu_alloc(void);
 
 #endif /* CONFIG_RISCV_PMU */
-- 
cgit v1.2.3


From e9991434596f5373dfd75857b445eb92a9253c56 Mon Sep 17 00:00:00 2001
From: Atish Patra
Date: Fri, 18 Feb 2022 16:46:57 -0800
Subject: RISC-V: Add perf platform driver based on SBI PMU extension

RISC-V SBI specification added a PMU extension that allows to configure
start/stop any pmu counter. The RISC-V perf can use most of the generic
perf features except interrupt overflow and event filtering based on
privilege mode which will be added in future.

It also allows to monitor a handful of firmware counters that can provide
insights into firmware activity during a performance analysis.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 drivers/perf/Kconfig           |  10 +
 drivers/perf/Makefile          |   1 +
 drivers/perf/riscv_pmu.c       |   2 +
 drivers/perf/riscv_pmu_sbi.c   | 578 +++++++++++++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h     |   1 +
 include/linux/perf/riscv_pmu.h |   6 +-
 6 files changed, 596 insertions(+), 2 deletions(-)
 create mode 100644 drivers/perf/riscv_pmu_sbi.c

(limited to 'drivers')

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index 386162ad858a..5645b5615c14 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -76,6 +76,16 @@ config RISCV_PMU_LEGACY
 	  of cycle/instruction counter and doesn't support counter overflow,
 	  or programmable counters. It will be removed in future.
 
+config RISCV_PMU_SBI
+	depends on RISCV_PMU && RISCV_SBI
+	bool "RISC-V PMU based on SBI PMU extension"
+	default y
+	help
+	  Say y if you want to use the CPU performance monitor
+	  using SBI PMU extension on RISC-V based systems. This option provides
+	  full perf feature support i.e. counter overflow, privilege mode
+	  filtering, counter configuration.
+
 config ARM_PMU_ACPI
 	depends on ARM_PMU && ACPI
 	def_bool y
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index c3d3268d495b..f149735166e1 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_QCOM_L2_PMU)	+= qcom_l2_pmu.o
 obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
 obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
 obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
+obj-$(CONFIG_RISCV_PMU_SBI) += riscv_pmu_sbi.o
 obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
 obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
 obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c
index 590a5789c128..b2b8d2074ed0 100644
--- a/drivers/perf/riscv_pmu.c
+++ b/drivers/perf/riscv_pmu.c
@@ -15,6 +15,8 @@
 #include <linux/printk.h>
 #include <linux/smp.h>
 
+#include <asm/sbi.h>
+
 static unsigned long csr_read_num(int csr_num)
 {
 #define switchcase_csr_read(__csr_num, __val)		{\
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
new file mode 100644
index 000000000000..815d5c509c64
--- /dev/null
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V performance counter support.
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ *
+ * This code is based on ARM perf event code which is in turn based on
+ * sparc64 and x86 code.
+ */
+
+#define pr_fmt(fmt) "riscv-pmu-sbi: " fmt
+
+#include <linux/mod_devicetable.h>
+#include <linux/perf/riscv_pmu.h>
+#include <linux/platform_device.h>
+
+#include <asm/sbi.h>
+
+union sbi_pmu_ctr_info {
+	unsigned long value;
+	struct {
+		unsigned long csr:12;
+		unsigned long width:6;
+#if __riscv_xlen == 32
+		unsigned long reserved:13;
+#else
+		unsigned long reserved:45;
+#endif
+		unsigned long type:1;
+	};
+};
+
+/**
+ * RISC-V doesn't have hetergenous harts yet. This need to be part of
+ * per_cpu in case of harts with different pmu counters
+ */
+static union sbi_pmu_ctr_info *pmu_ctr_list;
+
+struct sbi_pmu_event_data {
+	union {
+		union {
+			struct hw_gen_event {
+				uint32_t event_code:16;
+				uint32_t event_type:4;
+				uint32_t reserved:12;
+			} hw_gen_event;
+			struct hw_cache_event {
+				uint32_t result_id:1;
+				uint32_t op_id:2;
+				uint32_t cache_id:13;
+				uint32_t event_type:4;
+				uint32_t reserved:12;
+			} hw_cache_event;
+		};
+		uint32_t event_idx;
+	};
+};
+
+static const struct sbi_pmu_event_data pmu_hw_event_map[] = {
+	[PERF_COUNT_HW_CPU_CYCLES]		= {.hw_gen_event = {
+							SBI_PMU_HW_CPU_CYCLES,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_INSTRUCTIONS]		= {.hw_gen_event = {
+							SBI_PMU_HW_INSTRUCTIONS,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_CACHE_REFERENCES]	= {.hw_gen_event = {
+							SBI_PMU_HW_CACHE_REFERENCES,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_CACHE_MISSES]		= {.hw_gen_event = {
+							SBI_PMU_HW_CACHE_MISSES,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS]	= {.hw_gen_event = {
+							SBI_PMU_HW_BRANCH_INSTRUCTIONS,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_BRANCH_MISSES]		= {.hw_gen_event = {
+							SBI_PMU_HW_BRANCH_MISSES,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_BUS_CYCLES]		= {.hw_gen_event = {
+							SBI_PMU_HW_BUS_CYCLES,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND]	= {.hw_gen_event = {
+							SBI_PMU_HW_STALLED_CYCLES_FRONTEND,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_STALLED_CYCLES_BACKEND]	= {.hw_gen_event = {
+							SBI_PMU_HW_STALLED_CYCLES_BACKEND,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+	[PERF_COUNT_HW_REF_CPU_CYCLES]		= {.hw_gen_event = {
+							SBI_PMU_HW_REF_CPU_CYCLES,
+							SBI_PMU_EVENT_TYPE_HW, 0}},
+};
+
+#define C(x) PERF_COUNT_HW_CACHE_##x
+static const struct sbi_pmu_event_data pmu_cache_event_map[PERF_COUNT_HW_CACHE_MAX]
+[PERF_COUNT_HW_CACHE_OP_MAX]
+[PERF_COUNT_HW_CACHE_RESULT_MAX] = {
+	[C(L1D)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_READ), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_READ), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_WRITE), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_WRITE), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_PREFETCH), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_PREFETCH), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+	},
+	[C(L1I)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event =	{C(RESULT_ACCESS),
+					C(OP_READ), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS), C(OP_READ),
+					C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_WRITE), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_WRITE), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_PREFETCH), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_PREFETCH), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+	},
+	[C(LL)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_READ), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_READ), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_WRITE), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_WRITE), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_PREFETCH), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_PREFETCH), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+	},
+	[C(DTLB)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_READ), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_READ), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_WRITE), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_WRITE), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_PREFETCH), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_PREFETCH), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+	},
+	[C(ITLB)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_READ), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_READ), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_WRITE), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_WRITE), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_PREFETCH), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_PREFETCH), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+	},
+	[C(BPU)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_READ), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_READ), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_WRITE), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_WRITE), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_PREFETCH), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_PREFETCH), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+	},
+	[C(NODE)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_READ), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_READ), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_WRITE), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_WRITE), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+					C(OP_PREFETCH), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+			[C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+					C(OP_PREFETCH), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+		},
+	},
+};
+
+static int pmu_sbi_ctr_get_width(int idx)
+{
+	return pmu_ctr_list[idx].width;
+}
+
+static bool pmu_sbi_ctr_is_fw(int cidx)
+{
+	union sbi_pmu_ctr_info *info;
+
+	info = &pmu_ctr_list[cidx];
+	if (!info)
+		return false;
+
+	return (info->type == SBI_PMU_CTR_TYPE_FW) ? true : false;
+}
+
+static int pmu_sbi_ctr_get_idx(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+	struct sbiret ret;
+	int idx;
+	uint64_t cbase = 0;
+	uint64_t cmask = GENMASK_ULL(rvpmu->num_counters - 1, 0);
+	unsigned long cflags = 0;
+
+	if (event->attr.exclude_kernel)
+		cflags |= SBI_PMU_CFG_FLAG_SET_SINH;
+	if (event->attr.exclude_user)
+		cflags |= SBI_PMU_CFG_FLAG_SET_UINH;
+
+	/* retrieve the available counter index */
+	ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_CFG_MATCH, cbase, cmask,
+			cflags, hwc->event_base, hwc->config, 0);
+	if (ret.error) {
+		pr_debug("Not able to find a counter for event %lx config %llx\n",
+			hwc->event_base, hwc->config);
+		return sbi_err_map_linux_errno(ret.error);
+	}
+
+	idx = ret.value;
+	if (idx >= rvpmu->num_counters || !pmu_ctr_list[idx].value)
+		return -ENOENT;
+
+	/* Additional sanity check for the counter id */
+	if (pmu_sbi_ctr_is_fw(idx)) {
+		if (!test_and_set_bit(idx, cpuc->used_fw_ctrs))
+			return idx;
+	} else {
+		if (!test_and_set_bit(idx, cpuc->used_hw_ctrs))
+			return idx;
+	}
+
+	return -ENOENT;
+}
+
+static void pmu_sbi_ctr_clear_idx(struct perf_event *event)
+{
+
+	struct hw_perf_event *hwc = &event->hw;
+	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+	int idx = hwc->idx;
+
+	if (pmu_sbi_ctr_is_fw(idx))
+		clear_bit(idx, cpuc->used_fw_ctrs);
+	else
+		clear_bit(idx, cpuc->used_hw_ctrs);
+}
+
+static int pmu_event_find_cache(u64 config)
+{
+	unsigned int cache_type, cache_op, cache_result, ret;
+
+	cache_type = (config >>  0) & 0xff;
+	if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
+		return -EINVAL;
+
+	cache_op = (config >>  8) & 0xff;
+	if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
+		return -EINVAL;
+
+	cache_result = (config >> 16) & 0xff;
+	if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+		return -EINVAL;
+
+	ret = pmu_cache_event_map[cache_type][cache_op][cache_result].event_idx;
+
+	return ret;
+}
+
+static bool pmu_sbi_is_fw_event(struct perf_event *event)
+{
+	u32 type = event->attr.type;
+	u64 config = event->attr.config;
+
+	if ((type == PERF_TYPE_RAW) && ((config >> 63) == 1))
+		return true;
+	else
+		return false;
+}
+
+static int pmu_sbi_event_map(struct perf_event *event, u64 *econfig)
+{
+	u32 type = event->attr.type;
+	u64 config = event->attr.config;
+	int bSoftware;
+	u64 raw_config_val;
+	int ret;
+
+	switch (type) {
+	case PERF_TYPE_HARDWARE:
+		if (config >= PERF_COUNT_HW_MAX)
+			return -EINVAL;
+		ret = pmu_hw_event_map[event->attr.config].event_idx;
+		break;
+	case PERF_TYPE_HW_CACHE:
+		ret = pmu_event_find_cache(config);
+		break;
+	case PERF_TYPE_RAW:
+		/*
+		 * As per SBI specification, the upper 16 bits must be unused for
+		 * a raw event. Use the MSB (63b) to distinguish between hardware
+		 * raw event and firmware events.
+		 */
+		bSoftware = config >> 63;
+		raw_config_val = config & RISCV_PMU_RAW_EVENT_MASK;
+		if (bSoftware) {
+			if (raw_config_val < SBI_PMU_FW_MAX)
+				ret = (raw_config_val & 0xFFFF) |
+				      (SBI_PMU_EVENT_TYPE_FW << 16);
+			else
+				return -EINVAL;
+		} else {
+			ret = RISCV_PMU_RAW_EVENT_IDX;
+			*econfig = raw_config_val;
+		}
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static u64 pmu_sbi_ctr_read(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+	struct sbiret ret;
+	union sbi_pmu_ctr_info info;
+	u64 val = 0;
+
+	if (pmu_sbi_is_fw_event(event)) {
+		ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ,
+				hwc->idx, 0, 0, 0, 0, 0);
+		if (!ret.error)
+			val = ret.value;
+	} else {
+		info = pmu_ctr_list[idx];
+		val = riscv_pmu_ctr_read_csr(info.csr);
+		if (IS_ENABLED(CONFIG_32BIT))
+			val = ((u64)riscv_pmu_ctr_read_csr(info.csr + 0x80)) << 31 | val;
+	}
+
+	return val;
+}
+
+static void pmu_sbi_ctr_start(struct perf_event *event, u64 ival)
+{
+	struct sbiret ret;
+	struct hw_perf_event *hwc = &event->hw;
+	unsigned long flag = SBI_PMU_START_FLAG_SET_INIT_VALUE;
+
+	ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, hwc->idx,
+			1, flag, ival, ival >> 32, 0);
+	if (ret.error && (ret.error != SBI_ERR_ALREADY_STARTED))
+		pr_err("Starting counter idx %d failed with error %d\n",
+			hwc->idx, sbi_err_map_linux_errno(ret.error));
+}
+
+static void pmu_sbi_ctr_stop(struct perf_event *event, unsigned long flag)
+{
+	struct sbiret ret;
+	struct hw_perf_event *hwc = &event->hw;
+
+	ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, hwc->idx, 1, flag, 0, 0, 0);
+	if (ret.error && (ret.error != SBI_ERR_ALREADY_STOPPED) &&
+		flag != SBI_PMU_STOP_FLAG_RESET)
+		pr_err("Stopping counter idx %d failed with error %d\n",
+			hwc->idx, sbi_err_map_linux_errno(ret.error));
+}
+
+static int pmu_sbi_find_num_ctrs(void)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_NUM_COUNTERS, 0, 0, 0, 0, 0, 0);
+	if (!ret.error)
+		return ret.value;
+	else
+		return sbi_err_map_linux_errno(ret.error);
+}
+
+static int pmu_sbi_get_ctrinfo(int nctr)
+{
+	struct sbiret ret;
+	int i, num_hw_ctr = 0, num_fw_ctr = 0;
+	union sbi_pmu_ctr_info cinfo;
+
+	pmu_ctr_list = kcalloc(nctr, sizeof(*pmu_ctr_list), GFP_KERNEL);
+	if (!pmu_ctr_list)
+		return -ENOMEM;
+
+	for (i = 0; i <= nctr; i++) {
+		ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_GET_INFO, i, 0, 0, 0, 0, 0);
+		if (ret.error)
+			/* The logical counter ids are not expected to be contiguous */
+			continue;
+		cinfo.value = ret.value;
+		if (cinfo.type == SBI_PMU_CTR_TYPE_FW)
+			num_fw_ctr++;
+		else
+			num_hw_ctr++;
+		pmu_ctr_list[i].value = cinfo.value;
+	}
+
+	pr_info("%d firmware and %d hardware counters\n", num_fw_ctr, num_hw_ctr);
+
+	return 0;
+}
+
+static int pmu_sbi_starting_cpu(unsigned int cpu, struct hlist_node *node)
+{
+	struct riscv_pmu *pmu = hlist_entry_safe(node, struct riscv_pmu, node);
+
+	/* Enable the access for TIME csr only from the user mode now */
+	csr_write(CSR_SCOUNTEREN, 0x2);
+
+	/* Stop all the counters so that they can be enabled from perf */
+	sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP,
+		  0, GENMASK_ULL(pmu->num_counters - 1, 0), 0, 0, 0, 0);
+
+	return 0;
+}
+
+static int pmu_sbi_dying_cpu(unsigned int cpu, struct hlist_node *node)
+{
+	/* Disable all counters access for user mode now */
+	csr_write(CSR_SCOUNTEREN, 0x0);
+
+	return 0;
+}
+
+static int pmu_sbi_device_probe(struct platform_device *pdev)
+{
+	struct riscv_pmu *pmu = NULL;
+	int num_counters;
+	int ret;
+
+	pr_info("SBI PMU extension is available\n");
+	pmu = riscv_pmu_alloc();
+	if (!pmu)
+		return -ENOMEM;
+
+	num_counters = pmu_sbi_find_num_ctrs();
+	if (num_counters < 0) {
+		pr_err("SBI PMU extension doesn't provide any counters\n");
+		return -ENODEV;
+	}
+
+	/* cache all the information about counters now */
+	if (pmu_sbi_get_ctrinfo(num_counters))
+		return -ENODEV;
+
+	pmu->num_counters = num_counters;
+	pmu->ctr_start = pmu_sbi_ctr_start;
+	pmu->ctr_stop = pmu_sbi_ctr_stop;
+	pmu->event_map = pmu_sbi_event_map;
+	pmu->ctr_get_idx = pmu_sbi_ctr_get_idx;
+	pmu->ctr_get_width = pmu_sbi_ctr_get_width;
+	pmu->ctr_clear_idx = pmu_sbi_ctr_clear_idx;
+	pmu->ctr_read = pmu_sbi_ctr_read;
+
+	ret = cpuhp_state_add_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
+	if (ret)
+		return ret;
+
+	ret = perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
+	if (ret) {
+		cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver pmu_sbi_driver = {
+	.probe		= pmu_sbi_device_probe,
+	.driver		= {
+		.name	= RISCV_PMU_PDEV_NAME,
+	},
+};
+
+static int __init pmu_sbi_devinit(void)
+{
+	int ret;
+	struct platform_device *pdev;
+
+	if (sbi_spec_version < sbi_mk_version(0, 3) ||
+	    sbi_probe_extension(SBI_EXT_PMU) <= 0) {
+		return 0;
+	}
+
+	ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_RISCV_STARTING,
+				      "perf/riscv/pmu:starting",
+				      pmu_sbi_starting_cpu, pmu_sbi_dying_cpu);
+	if (ret) {
+		pr_err("CPU hotplug notifier could not be registered: %d\n",
+		       ret);
+		return ret;
+	}
+
+	ret = platform_driver_register(&pmu_sbi_driver);
+	if (ret)
+		return ret;
+
+	pdev = platform_device_register_simple(RISCV_PMU_PDEV_NAME, -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		platform_driver_unregister(&pmu_sbi_driver);
+		return PTR_ERR(pdev);
+	}
+
+	/* Notify legacy implementation that SBI pmu is available*/
+	riscv_pmu_legacy_skip_init();
+
+	return ret;
+}
+device_initcall(pmu_sbi_devinit)
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 411a428ace4d..51c7e4929df7 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -165,6 +165,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
 	CPUHP_AP_PERF_ARM_ACPI_STARTING,
 	CPUHP_AP_PERF_ARM_STARTING,
+	CPUHP_AP_PERF_RISCV_STARTING,
 	CPUHP_AP_ARM_L2X0_STARTING,
 	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
diff --git a/include/linux/perf/riscv_pmu.h b/include/linux/perf/riscv_pmu.h
index 9140c491fc54..0f226948c0ca 100644
--- a/include/linux/perf/riscv_pmu.h
+++ b/include/linux/perf/riscv_pmu.h
@@ -31,8 +31,10 @@ struct cpu_hw_events {
 	int			n_events;
 	/* currently enabled events */
 	struct perf_event	*events[RISCV_MAX_COUNTERS];
-	/* currently enabled counters */
-	DECLARE_BITMAP(used_event_ctrs, RISCV_MAX_COUNTERS);
+	/* currently enabled hardware counters */
+	DECLARE_BITMAP(used_hw_ctrs, RISCV_MAX_COUNTERS);
+	/* currently enabled firmware counters */
+	DECLARE_BITMAP(used_fw_ctrs, RISCV_MAX_COUNTERS);
 };
 
 struct riscv_pmu {
-- 
cgit v1.2.3


From 4905ec2fb7e6421c14c9fb7276f5aa92f60f2b98 Mon Sep 17 00:00:00 2001
From: Atish Patra
Date: Fri, 18 Feb 2022 16:46:58 -0800
Subject: RISC-V: Add sscofpmf extension support

The sscofpmf extension allows counter overflow and filtering for
programmable counters. Enable the perf driver to handle the overflow
interrupt. The overflow interrupt is a hart local interrupt.
Thus, per cpu overflow interrupts are setup as a child under the root
INTC irq domain.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/include/asm/csr.h   |   8 +-
 arch/riscv/include/asm/hwcap.h |   1 +
 arch/riscv/kernel/cpu.c        |   1 +
 arch/riscv/kernel/cpufeature.c |   2 +
 drivers/perf/riscv_pmu_sbi.c   | 222 ++++++++++++++++++++++++++++++++++++++++-
 include/linux/perf/riscv_pmu.h |   2 +
 6 files changed, 230 insertions(+), 6 deletions(-)

(limited to 'drivers')

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index ce493df11177..8b2e48077731 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -65,6 +65,7 @@
 #define IRQ_S_EXT		9
 #define IRQ_VS_EXT		10
 #define IRQ_M_EXT		11
+#define IRQ_PMU_OVF		13
 
 /* Exception causes */
 #define EXC_INST_MISALIGNED	0
@@ -212,6 +213,8 @@
 #define CSR_HPMCOUNTER30H	0xc9e
 #define CSR_HPMCOUNTER31H	0xc9f
 
+#define CSR_SSCOUNTOVF		0xda0
+
 #define CSR_SSTATUS		0x100
 #define CSR_SIE			0x104
 #define CSR_STVEC		0x105
@@ -298,7 +301,10 @@
 # define RV_IRQ_SOFT		IRQ_S_SOFT
 # define RV_IRQ_TIMER	IRQ_S_TIMER
 # define RV_IRQ_EXT		IRQ_S_EXT
-#endif /* CONFIG_RISCV_M_MODE */
+# define RV_IRQ_PMU	IRQ_PMU_OVF
+# define SIP_LCOFIP     (_AC(0x1, UL) << IRQ_PMU_OVF)
+
+#endif /* !CONFIG_RISCV_M_MODE */
 
 /* IE/IP (Supervisor/Machine Interrupt Enable/Pending) flags */
 #define IE_SIE		(_AC(0x1, UL) << RV_IRQ_SOFT)
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 691fc9c8099b..0734e42f74f2 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -51,6 +51,7 @@ extern unsigned long elf_hwcap;
  * available logical extension id.
  */
 enum riscv_isa_ext_id {
+	RISCV_ISA_EXT_SSCOFPMF = RISCV_ISA_EXT_BASE,
 	RISCV_ISA_EXT_ID_MAX = RISCV_ISA_EXT_MAX,
 };
 
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index fc115e307ef5..c11cb576394d 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -87,6 +87,7 @@ int riscv_of_parent_hartid(struct device_node *node)
  *    extensions by an underscore.
  */
 static struct riscv_isa_ext_data isa_ext_arr[] = {
+	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
 	__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
 };
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index a43c08af5f4b..1b2d42d7f589 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -190,6 +190,8 @@ void __init riscv_fill_hwcap(void)
 			if (!ext_long) {
 				this_hwcap |= isa2hwcap[(unsigned char)(*ext)];
 				set_bit(*ext - 'a', this_isa);
+			} else {
+				SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF);
 			}
 #undef SET_ISA_EXT_MAP
 		}
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 815d5c509c64..a1317a483512 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -13,8 +13,13 @@
 #include <linux/mod_devicetable.h>
 #include <linux/perf/riscv_pmu.h>
 #include <linux/platform_device.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of_irq.h>
+#include <linux/of.h>
 
 #include <asm/sbi.h>
+#include <asm/hwcap.h>
 
 union sbi_pmu_ctr_info {
 	unsigned long value;
@@ -35,6 +40,7 @@ union sbi_pmu_ctr_info {
  * per_cpu in case of harts with different pmu counters
  */
 static union sbi_pmu_ctr_info *pmu_ctr_list;
+static unsigned int riscv_pmu_irq;
 
 struct sbi_pmu_event_data {
 	union {
@@ -469,33 +475,229 @@ static int pmu_sbi_get_ctrinfo(int nctr)
 	return 0;
 }
 
+static inline void pmu_sbi_stop_all(struct riscv_pmu *pmu)
+{
+	/**
+	 * No need to check the error because we are disabling all the counters
+	 * which may include counters that are not enabled yet.
+	 */
+	sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP,
+		  0, GENMASK_ULL(pmu->num_counters - 1, 0), 0, 0, 0, 0);
+}
+
+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);
+
+	/* 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], 0, 0, 0, 0);
+}
+
+/**
+ * This function starts all the used counters in two step approach.
+ * Any counter that did not overflow can be start in a single step
+ * while the overflowed counters need to be started with updated initialization
+ * value.
+ */
+static inline void pmu_sbi_start_overflow_mask(struct riscv_pmu *pmu,
+					       unsigned long ctr_ovf_mask)
+{
+	int idx = 0;
+	struct cpu_hw_events *cpu_hw_evt = this_cpu_ptr(pmu->hw_events);
+	struct perf_event *event;
+	unsigned long flag = SBI_PMU_START_FLAG_SET_INIT_VALUE;
+	unsigned long ctr_start_mask = 0;
+	uint64_t max_period;
+	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);
+
+	/* Reinitialize and start all the counter that overflowed */
+	while (ctr_ovf_mask) {
+		if (ctr_ovf_mask & 0x01) {
+			event = cpu_hw_evt->events[idx];
+			hwc = &event->hw;
+			max_period = riscv_pmu_ctr_get_width_mask(event);
+			init_val = local64_read(&hwc->prev_count) & max_period;
+			sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, idx, 1,
+				  flag, init_val, 0, 0);
+		}
+		ctr_ovf_mask = ctr_ovf_mask >> 1;
+		idx++;
+	}
+}
+
+static irqreturn_t pmu_sbi_ovf_handler(int irq, void *dev)
+{
+	struct perf_sample_data data;
+	struct pt_regs *regs;
+	struct hw_perf_event *hw_evt;
+	union sbi_pmu_ctr_info *info;
+	int lidx, hidx, fidx;
+	struct riscv_pmu *pmu;
+	struct perf_event *event;
+	unsigned long overflow;
+	unsigned long overflowed_ctrs = 0;
+	struct cpu_hw_events *cpu_hw_evt = dev;
+
+	if (WARN_ON_ONCE(!cpu_hw_evt))
+		return IRQ_NONE;
+
+	/* Firmware counter don't support overflow yet */
+	fidx = find_first_bit(cpu_hw_evt->used_hw_ctrs, RISCV_MAX_COUNTERS);
+	event = cpu_hw_evt->events[fidx];
+	if (!event) {
+		csr_clear(CSR_SIP, SIP_LCOFIP);
+		return IRQ_NONE;
+	}
+
+	pmu = to_riscv_pmu(event->pmu);
+	pmu_sbi_stop_hw_ctrs(pmu);
+
+	/* Overflow status register should only be read after counter are stopped */
+	overflow = csr_read(CSR_SSCOUNTOVF);
+
+	/**
+	 * Overflow interrupt pending bit should only be cleared after stopping
+	 * all the counters to avoid any race condition.
+	 */
+	csr_clear(CSR_SIP, SIP_LCOFIP);
+
+	/* No overflow bit is set */
+	if (!overflow)
+		return IRQ_NONE;
+
+	regs = get_irq_regs();
+
+	for_each_set_bit(lidx, cpu_hw_evt->used_hw_ctrs, RISCV_MAX_COUNTERS) {
+		struct perf_event *event = cpu_hw_evt->events[lidx];
+
+		/* Skip if invalid event or user did not request a sampling */
+		if (!event || !is_sampling_event(event))
+			continue;
+
+		info = &pmu_ctr_list[lidx];
+		/* Do a sanity check */
+		if (!info || info->type != SBI_PMU_CTR_TYPE_HW)
+			continue;
+
+		/* compute hardware counter index */
+		hidx = info->csr - CSR_CYCLE;
+		/* check if the corresponding bit is set in sscountovf */
+		if (!(overflow & (1 << hidx)))
+			continue;
+
+		/*
+		 * Keep a track of overflowed counters so that they can be started
+		 * with updated initial value.
+		 */
+		overflowed_ctrs |= 1 << lidx;
+		hw_evt = &event->hw;
+		riscv_pmu_event_update(event);
+		perf_sample_data_init(&data, 0, hw_evt->last_period);
+		if (riscv_pmu_event_set_period(event)) {
+			/*
+			 * Unlike other ISAs, RISC-V don't have to disable interrupts
+			 * to avoid throttling here. As per the specification, the
+			 * interrupt remains disabled until the OF bit is set.
+			 * Interrupts are enabled again only during the start.
+			 * TODO: We will need to stop the guest counters once
+			 * virtualization support is added.
+			 */
+			perf_event_overflow(event, &data, regs);
+		}
+	}
+	pmu_sbi_start_overflow_mask(pmu, overflowed_ctrs);
+
+	return IRQ_HANDLED;
+}
+
 static int pmu_sbi_starting_cpu(unsigned int cpu, struct hlist_node *node)
 {
 	struct riscv_pmu *pmu = hlist_entry_safe(node, struct riscv_pmu, node);
+	struct cpu_hw_events *cpu_hw_evt = this_cpu_ptr(pmu->hw_events);
 
 	/* Enable the access for TIME csr only from the user mode now */
 	csr_write(CSR_SCOUNTEREN, 0x2);
 
 	/* Stop all the counters so that they can be enabled from perf */
-	sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP,
-		  0, GENMASK_ULL(pmu->num_counters - 1, 0), 0, 0, 0, 0);
+	pmu_sbi_stop_all(pmu);
+
+	if (riscv_isa_extension_available(NULL, SSCOFPMF)) {
+		cpu_hw_evt->irq = riscv_pmu_irq;
+		csr_clear(CSR_IP, BIT(RV_IRQ_PMU));
+		csr_set(CSR_IE, BIT(RV_IRQ_PMU));
+		enable_percpu_irq(riscv_pmu_irq, IRQ_TYPE_NONE);
+	}
 
 	return 0;
 }
 
 static int pmu_sbi_dying_cpu(unsigned int cpu, struct hlist_node *node)
 {
+	if (riscv_isa_extension_available(NULL, SSCOFPMF)) {
+		disable_percpu_irq(riscv_pmu_irq);
+		csr_clear(CSR_IE, BIT(RV_IRQ_PMU));
+	}
+
 	/* Disable all counters access for user mode now */
 	csr_write(CSR_SCOUNTEREN, 0x0);
 
 	return 0;
 }
 
+static int pmu_sbi_setup_irqs(struct riscv_pmu *pmu, struct platform_device *pdev)
+{
+	int ret;
+	struct cpu_hw_events __percpu *hw_events = pmu->hw_events;
+	struct device_node *cpu, *child;
+	struct irq_domain *domain = NULL;
+
+	if (!riscv_isa_extension_available(NULL, SSCOFPMF))
+		return -EOPNOTSUPP;
+
+	for_each_of_cpu_node(cpu) {
+		child = of_get_compatible_child(cpu, "riscv,cpu-intc");
+		if (!child) {
+			pr_err("Failed to find INTC node\n");
+			return -ENODEV;
+		}
+		domain = irq_find_host(child);
+		of_node_put(child);
+		if (domain)
+			break;
+	}
+	if (!domain) {
+		pr_err("Failed to find INTC IRQ root domain\n");
+		return -ENODEV;
+	}
+
+	riscv_pmu_irq = irq_create_mapping(domain, RV_IRQ_PMU);
+	if (!riscv_pmu_irq) {
+		pr_err("Failed to map PMU interrupt for node\n");
+		return -ENODEV;
+	}
+
+	ret = request_percpu_irq(riscv_pmu_irq, pmu_sbi_ovf_handler, "riscv-pmu", hw_events);
+	if (ret) {
+		pr_err("registering percpu irq failed [%d]\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int pmu_sbi_device_probe(struct platform_device *pdev)
 {
 	struct riscv_pmu *pmu = NULL;
 	int num_counters;
-	int ret;
+	int ret = -ENODEV;
 
 	pr_info("SBI PMU extension is available\n");
 	pmu = riscv_pmu_alloc();
@@ -505,13 +707,19 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
 	num_counters = pmu_sbi_find_num_ctrs();
 	if (num_counters < 0) {
 		pr_err("SBI PMU extension doesn't provide any counters\n");
-		return -ENODEV;
+		goto out_free;
 	}
 
 	/* cache all the information about counters now */
 	if (pmu_sbi_get_ctrinfo(num_counters))
-		return -ENODEV;
+		goto out_free;
 
+	ret = pmu_sbi_setup_irqs(pmu, pdev);
+	if (ret < 0) {
+		pr_info("Perf sampling/filtering is not supported as sscof extension is not available\n");
+		pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+		pmu->pmu.capabilities |= PERF_PMU_CAP_NO_EXCLUDE;
+	}
 	pmu->num_counters = num_counters;
 	pmu->ctr_start = pmu_sbi_ctr_start;
 	pmu->ctr_stop = pmu_sbi_ctr_stop;
@@ -532,6 +740,10 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
 	}
 
 	return 0;
+
+out_free:
+	kfree(pmu);
+	return ret;
 }
 
 static struct platform_driver pmu_sbi_driver = {
diff --git a/include/linux/perf/riscv_pmu.h b/include/linux/perf/riscv_pmu.h
index 0f226948c0ca..46f9b6fe306e 100644
--- a/include/linux/perf/riscv_pmu.h
+++ b/include/linux/perf/riscv_pmu.h
@@ -29,6 +29,8 @@
 struct cpu_hw_events {
 	/* currently enabled events */
 	int			n_events;
+	/* Counter overflow interrupt */
+	int		irq;
 	/* currently enabled events */
 	struct perf_event	*events[RISCV_MAX_COUNTERS];
 	/* currently enabled hardware counters */
-- 
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