Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Zong Li <zong.li@sifive.com>
To:     palmer@dabbelt.com, paul.walmsley@sifive.com,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     Zong Li <zong.li@sifive.com>
Subject: [RFC PATCH 5/6] riscv: perf: introduce DT mechanism
Date:   Mon, 29 Jun 2020 11:19:14 +0800
Message-Id: <da261dc8b456fc0dd67508d98b16838bcd697220.1593397455.git.zong.li@sifive.com>
In-Reply-To: <cover.1593397455.git.zong.li@sifive.com>
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Each architecture is responsible for mapping generic hardware and cache
events to their own specific encoding of hardware events. For each
architecture, it also have to distinguish the defination of hardware
events of different platforms of each vendor. We use DT file to describe
platform-specific information to make our perf implementation more
generic and common.

Signed-off-by: Zong Li <zong.li@sifive.com>
---
 arch/riscv/include/asm/perf_event.h |  55 ++----
 arch/riscv/kernel/perf_event.c      | 273 +++++++++++++---------------
 2 files changed, 139 insertions(+), 189 deletions(-)

diff --git a/arch/riscv/include/asm/perf_event.h b/arch/riscv/include/asm/perf_event.h
index 41d515a1f331..e95d3bbaae3e 100644
--- a/arch/riscv/include/asm/perf_event.h
+++ b/arch/riscv/include/asm/perf_event.h
@@ -17,6 +17,8 @@
 #define RISCV_EVENT_COUNTERS	29
 #define RISCV_TOTAL_COUNTERS	(RISCV_BASE_COUNTERS + RISCV_EVENT_COUNTERS)
 
+#define RISCV_DEFAULT_WIDTH_COUNTER	64
+
 /*
  * According to the spec, an implementation can support counter up to
  * mhpmcounter31, but many high-end processors has at most 6 general
@@ -33,9 +35,21 @@
 
 #define RISCV_PMU_HPMCOUNTER_FIRST	3
 #define RISCV_PMU_HPMCOUNTER_LAST					\
-	(RISCV_PMU_HPMCOUNTER_FIRST + riscv_pmu->num_counters - 1)
+	(RISCV_PMU_HPMCOUNTER_FIRST + riscv_pmu.num_event_cntr - 1)
+
+#define RISCV_OP_UNSUPP			(-EOPNOTSUPP)
+
+#define RISCV_MAP_ALL_UNSUPPORTED					\
+	[0 ... PERF_COUNT_HW_MAX - 1] = RISCV_OP_UNSUPP
 
-#define RISCV_OP_UNSUPP		(-EOPNOTSUPP)
+#define C(x) PERF_COUNT_HW_CACHE_##x
+
+#define RISCV_CACHE_MAP_ALL_UNSUPPORTED					\
+[0 ... C(MAX) - 1] = {							\
+	[0 ... C(OP_MAX) - 1] = {					\
+		[0 ... C(RESULT_MAX) - 1] = RISCV_OP_UNSUPP,		\
+	},								\
+}
 
 /* Hardware cache event encoding */
 #define PERF_HW_CACHE_TYPE		0
@@ -65,43 +79,6 @@
 #define CSR_MHPMEVENT7	0x327
 #define CSR_MHPMEVENT8	0x328
 
-struct cpu_hw_events {
-	/* # currently enabled events*/
-	int			n_events;
-	/* currently enabled events */
-	struct perf_event	*events[RISCV_EVENT_COUNTERS];
-	/* bitmap of used event counters */
-	unsigned long		used_cntr_mask;
-	/* vendor-defined PMU data */
-	void			*platform;
-};
-
-struct riscv_pmu {
-	struct pmu	*pmu;
-
-	/* generic hw/cache events table */
-	const int	*hw_events;
-	const int	(*cache_events)[PERF_COUNT_HW_CACHE_MAX]
-				       [PERF_COUNT_HW_CACHE_OP_MAX]
-				       [PERF_COUNT_HW_CACHE_RESULT_MAX];
-	/* method used to map hw/cache events */
-	int		(*map_hw_event)(u64 config);
-	int		(*map_cache_event)(u64 config);
-
-	/* max generic hw events in map */
-	int		max_events;
-	/* number total counters, 2(base) + x(general) */
-	int		num_counters;
-	/* the width of the counter */
-	int		counter_width;
-
-	/* vendor-defined PMU features */
-	void		*platform;
-
-	irqreturn_t	(*handle_irq)(int irq_num, void *dev);
-	int		irq;
-};
-
 #endif
 #ifdef CONFIG_PERF_EVENTS
 #define perf_arch_bpf_user_pt_regs(regs) (struct user_regs_struct *)regs
diff --git a/arch/riscv/kernel/perf_event.c b/arch/riscv/kernel/perf_event.c
index 0cfcd6f1e57b..3bdfbe4efd5c 100644
--- a/arch/riscv/kernel/perf_event.c
+++ b/arch/riscv/kernel/perf_event.c
@@ -9,6 +9,7 @@
  * Copyright (C) 2009 Google, Inc., Stephane Eranian
  * Copyright 2014 Tilera Corporation. All Rights Reserved.
  * Copyright (C) 2018 Andes Technology Corporation
+ * Copyright (C) 2020 SiFive
  *
  * Perf_events support for RISC-V platforms.
  *
@@ -30,113 +31,55 @@
 #include <linux/perf_event.h>
 #include <linux/atomic.h>
 #include <linux/of.h>
+#include <asm/csr.h>
 #include <asm/perf_event.h>
 
-static const struct riscv_pmu *riscv_pmu __read_mostly;
+static struct riscv_pmu {
+	struct pmu	*pmu;
+
+	/* number of event counters */
+	int		num_event_cntr;
+
+	/* the width of base counters */
+	int		width_base_cntr;
+
+	/* the width of event counters */
+	int		width_event_cntr;
+
+	irqreturn_t	(*handle_irq)(int irq_num, void *dev);
+
+	int		irq;
+} riscv_pmu;
+
+struct cpu_hw_events {
+	/* # currently enabled events*/
+	int			n_events;
+
+	/* currently enabled events */
+	struct perf_event	*events[RISCV_EVENT_COUNTERS];
+
+	/* bitmap of used event counters */
+	unsigned long		used_cntr_mask;
+};
+
 static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
 
 /*
  * Hardware & cache maps and their methods
  */
 
-static const int riscv_hw_event_map[] = {
-	[PERF_COUNT_HW_CPU_CYCLES]		= RISCV_PMU_CYCLE,
-	[PERF_COUNT_HW_INSTRUCTIONS]		= RISCV_PMU_INSTRET,
-	[PERF_COUNT_HW_CACHE_REFERENCES]	= RISCV_OP_UNSUPP,
-	[PERF_COUNT_HW_CACHE_MISSES]		= RISCV_OP_UNSUPP,
-	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS]	= RISCV_OP_UNSUPP,
-	[PERF_COUNT_HW_BRANCH_MISSES]		= RISCV_OP_UNSUPP,
-	[PERF_COUNT_HW_BUS_CYCLES]		= RISCV_OP_UNSUPP,
+static int riscv_hw_event_map[PERF_COUNT_HW_MAX] = {
+	RISCV_MAP_ALL_UNSUPPORTED,
+
+	/* Specify base pmu, even if they aren't present in DT file */
+	[PERF_COUNT_HW_CPU_CYCLES]	= RISCV_PMU_CYCLE,
+	[PERF_COUNT_HW_INSTRUCTIONS]	= RISCV_PMU_INSTRET,
 };
 
-#define C(x) PERF_COUNT_HW_CACHE_##x
-static const int riscv_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)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_WRITE)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_PREFETCH)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-	},
-	[C(L1I)] = {
-		[C(OP_READ)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_WRITE)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_PREFETCH)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-	},
-	[C(LL)] = {
-		[C(OP_READ)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_WRITE)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_PREFETCH)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-	},
-	[C(DTLB)] = {
-		[C(OP_READ)] = {
-			[C(RESULT_ACCESS)] =  RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] =  RISCV_OP_UNSUPP,
-		},
-		[C(OP_WRITE)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_PREFETCH)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-	},
-	[C(ITLB)] = {
-		[C(OP_READ)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_WRITE)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_PREFETCH)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-	},
-	[C(BPU)] = {
-		[C(OP_READ)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_WRITE)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-		[C(OP_PREFETCH)] = {
-			[C(RESULT_ACCESS)] = RISCV_OP_UNSUPP,
-			[C(RESULT_MISS)] = RISCV_OP_UNSUPP,
-		},
-	},
+static int riscv_cache_event_map[PERF_COUNT_HW_CACHE_MAX]
+				[PERF_COUNT_HW_CACHE_OP_MAX]
+				[PERF_COUNT_HW_CACHE_RESULT_MAX] = {
+	RISCV_CACHE_MAP_ALL_UNSUPPORTED,
 };
 
 /*
@@ -154,6 +97,17 @@ static inline int is_event_counter(int idx)
 		idx <= RISCV_PMU_HPMCOUNTER_LAST);
 }
 
+static inline int get_counter_width(int idx)
+{
+	if (is_base_counter(idx))
+		return riscv_pmu.width_base_cntr;
+
+	if (is_event_counter(idx))
+		return riscv_pmu.width_event_cntr;
+
+	return 0;
+}
+
 static inline int get_available_counter(struct perf_event *event)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
@@ -188,10 +142,14 @@ static inline int get_available_counter(struct perf_event *event)
  */
 static int riscv_map_hw_event(u64 config)
 {
-	if (config >= riscv_pmu->max_events)
+	int ret;
+
+	if (config >= PERF_COUNT_HW_MAX)
 		return -EINVAL;
 
-	return riscv_pmu->hw_events[config];
+	ret = riscv_hw_event_map[config];
+
+	return ret == RISCV_OP_UNSUPP ? -ENOENT : ret;
 }
 
 /*
@@ -355,7 +313,7 @@ static void riscv_pmu_read(struct perf_event *event)
 	 * delta is the value to update the counter we maintain in the kernel.
 	 */
 	delta = (new_raw_count - prev_raw_count) &
-		((1ULL << riscv_pmu->counter_width) - 1);
+		((1ULL << get_counter_width(idx)) - 1);
 
 	local64_add(delta, &event->count);
 	/*
@@ -386,7 +344,7 @@ static void riscv_pmu_stop(struct perf_event *event, int flags)
 	hwc->state |= PERF_HES_STOPPED;
 
 	if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
-		riscv_pmu->pmu->read(event);
+		riscv_pmu_read(event);
 		hwc->state |= PERF_HES_UPTODATE;
 	}
 }
@@ -429,7 +387,7 @@ static int riscv_pmu_add(struct perf_event *event, int flags)
 	struct hw_perf_event *hwc = &event->hw;
 	int count_idx;
 
-	if (cpuc->n_events == riscv_pmu->num_counters)
+	if (cpuc->n_events == riscv_pmu.num_event_cntr)
 		return -ENOSPC;
 
 	count_idx = get_available_counter(event);
@@ -437,13 +395,13 @@ static int riscv_pmu_add(struct perf_event *event, int flags)
 		return -ENOSPC;
 
 	cpuc->n_events++;
+
 	hwc->idx = count_idx;
-	cpuc->events[hwc->idx] = event;
 
 	hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
 
 	if (flags & PERF_EF_START)
-		riscv_pmu->pmu->start(event, PERF_EF_RELOAD);
+		riscv_pmu_start(event, PERF_EF_RELOAD);
 
 	return 0;
 }
@@ -459,8 +417,8 @@ static void riscv_pmu_del(struct perf_event *event, int flags)
 	cpuc->n_events--;
 	__clear_bit(hwc->idx, &cpuc->used_cntr_mask);
 
-	cpuc->events[hwc->idx] = NULL;
-	riscv_pmu->pmu->stop(event, PERF_EF_UPDATE);
+	riscv_pmu_stop(event, PERF_EF_UPDATE);
+
 	perf_event_update_userpage(event);
 }
 
@@ -470,7 +428,7 @@ static void riscv_pmu_del(struct perf_event *event, int flags)
 
 static DEFINE_MUTEX(pmc_reserve_mutex);
 
-static irqreturn_t riscv_base_pmu_handle_irq(int irq_num, void *dev)
+static irqreturn_t riscv_pmu_handle_irq(int irq_num, void *dev)
 {
 	return IRQ_NONE;
 }
@@ -480,8 +438,8 @@ static int reserve_pmc_hardware(void)
 	int err = 0;
 
 	mutex_lock(&pmc_reserve_mutex);
-	if (riscv_pmu->irq >= 0 && riscv_pmu->handle_irq) {
-		err = request_irq(riscv_pmu->irq, riscv_pmu->handle_irq,
+	if (riscv_pmu.irq >= 0 && riscv_pmu.handle_irq) {
+		err = request_irq(riscv_pmu.irq, riscv_pmu.handle_irq,
 				  IRQF_PERCPU, "riscv-base-perf", NULL);
 	}
 	mutex_unlock(&pmc_reserve_mutex);
@@ -492,8 +450,8 @@ static int reserve_pmc_hardware(void)
 static void release_pmc_hardware(void)
 {
 	mutex_lock(&pmc_reserve_mutex);
-	if (riscv_pmu->irq >= 0)
-		free_irq(riscv_pmu->irq, NULL);
+	if (riscv_pmu.irq >= 0)
+		free_irq(riscv_pmu.irq, NULL);
 	mutex_unlock(&pmc_reserve_mutex);
 }
 
@@ -529,10 +487,10 @@ static int riscv_event_init(struct perf_event *event)
 
 	switch (event->attr.type) {
 	case PERF_TYPE_HARDWARE:
-		code = riscv_pmu->map_hw_event(attr->config);
+		code = riscv_map_hw_event(attr->config);
 		break;
 	case PERF_TYPE_HW_CACHE:
-		code = riscv_pmu->map_cache_event(attr->config);
+		code = riscv_map_cache_event(attr->config);
 		break;
 	case PERF_TYPE_RAW:
 		code = attr->config;
@@ -555,9 +513,6 @@ static int riscv_event_init(struct perf_event *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().
-	 *
-	 * But since we don't have such support, later in pmu->add(), we just
-	 * use hwc->config as the index instead.
 	 */
 	hwc->config_base = config_base;
 	hwc->config = code;
@@ -570,52 +525,70 @@ static int riscv_event_init(struct perf_event *event)
  * Initialization
  */
 
-static struct pmu min_pmu = {
-	.name		= "riscv-base",
-	.event_init	= riscv_event_init,
-	.add		= riscv_pmu_add,
-	.del		= riscv_pmu_del,
-	.start		= riscv_pmu_start,
-	.stop		= riscv_pmu_stop,
-	.read		= riscv_pmu_read,
-};
+static struct riscv_pmu riscv_pmu = {
+	.pmu = &(struct pmu) {
+		.name		= "riscv-pmu",
+		.event_init	= riscv_event_init,
+		.add		= riscv_pmu_add,
+		.del		= riscv_pmu_del,
+		.start		= riscv_pmu_start,
+		.stop		= riscv_pmu_stop,
+		.read		= riscv_pmu_read,
+	},
 
-static const struct riscv_pmu riscv_base_pmu = {
-	.pmu = &min_pmu,
-	.max_events = ARRAY_SIZE(riscv_hw_event_map),
-	.map_hw_event = riscv_map_hw_event,
-	.hw_events = riscv_hw_event_map,
-	.map_cache_event = riscv_map_cache_event,
-	.cache_events = &riscv_cache_event_map,
-	.counter_width = 63,
-	.num_counters = RISCV_BASE_COUNTERS + 0,
-	.handle_irq = &riscv_base_pmu_handle_irq,
+	.num_event_cntr = 0,
+	.width_event_cntr = RISCV_DEFAULT_WIDTH_COUNTER,
+	.width_base_cntr = RISCV_DEFAULT_WIDTH_COUNTER,
 
+	.handle_irq = &riscv_pmu_handle_irq,
 	/* This means this PMU has no IRQ. */
 	.irq = -1,
 };
 
-static const struct of_device_id riscv_pmu_of_ids[] = {
-	{.compatible = "riscv,base-pmu",	.data = &riscv_base_pmu},
-	{ /* sentinel value */ }
-};
+static int __init init_riscv_pmu(struct device_node *node)
+{
+	int num_events, key, value, i;
+
+	of_property_read_u32(node, "riscv,width-base-cntr", &riscv_pmu.width_base_cntr);
+
+	of_property_read_u32(node, "riscv,width-event-cntr", &riscv_pmu.width_event_cntr);
+
+	of_property_read_u32(node, "riscv,n-event-cntr", &riscv_pmu.num_event_cntr);
+	if (riscv_pmu.num_event_cntr > RISCV_EVENT_COUNTERS)
+		riscv_pmu.num_event_cntr = RISCV_EVENT_COUNTERS;
+
+	num_events = of_property_count_u32_elems(node, "riscv,hw-event-map");
+	if (num_events > 0 && num_events % 2 == 0)
+		for (i = 0; i < num_events;) {
+			of_property_read_u32_index(node, "riscv,hw-event-map", i++, &key);
+			of_property_read_u32_index(node, "riscv,hw-event-map", i++, &value);
+			riscv_hw_event_map[key] = value;
+		}
+
+	num_events = of_property_count_u32_elems(node, "riscv,hw-cache-event-map");
+	if (num_events > 0 && num_events % 2 == 0)
+		for (i = 0; i < num_events;) {
+			of_property_read_u32_index(node, "riscv,hw-cache-event-map", i++, &key);
+			of_property_read_u32_index(node, "riscv,hw-cache-event-map", i++, &value);
+			riscv_cache_event_map
+				[(key >> PERF_HW_CACHE_TYPE) & PERF_HW_CACHE_MASK]
+				[(key >> PERF_HW_CACHE_OP) & PERF_HW_CACHE_MASK]
+				[(key >> PERF_HW_CACHE_RESULT) & PERF_HW_CACHE_MASK] = value;
+		}
+
+	return 0;
+}
 
 static int __init init_hw_perf_events(void)
 {
-	struct device_node *node = of_find_node_by_type(NULL, "pmu");
-	const struct of_device_id *of_id;
+	struct device_node *node = of_find_compatible_node(NULL, NULL, "riscv,pmu");
 
-	riscv_pmu = &riscv_base_pmu;
+	if (node)
+		init_riscv_pmu(node);
 
-	if (node) {
-		of_id = of_match_node(riscv_pmu_of_ids, node);
-
-		if (of_id)
-			riscv_pmu = of_id->data;
-		of_node_put(node);
-	}
+	/* Even if there is no pmu node in DT, we reach here for base PMU. */
+	perf_pmu_register(riscv_pmu.pmu, "cpu", PERF_TYPE_RAW);
 
-	perf_pmu_register(riscv_pmu->pmu, "cpu", PERF_TYPE_RAW);
 	return 0;
 }
 arch_initcall(init_hw_perf_events);
-- 
2.27.0