1 files changed, 363 insertions, 0 deletions
diff --git a/arch/sh/kernel/perf_event.c b/arch/sh/kernel/perf_event.c
new file mode 100644
index 000000000..1d2507f22
--- /dev/null
+++ b/arch/sh/kernel/perf_event.c
@@ -0,0 +1,363 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Performance event support framework for SuperH hardware counters.
+ *
+ *  Copyright (C) 2009  Paul Mundt
+ *
+ * Heavily based on the x86 and PowerPC implementations.
+ *
+ * x86:
+ *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
+ *  Copyright (C) 2009 Jaswinder Singh Rajput
+ *  Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
+ *  Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra
+ *  Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
+ *
+ * ppc:
+ *  Copyright 2008-2009 Paul Mackerras, IBM Corporation.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/perf_event.h>
+#include <linux/export.h>
+#include <asm/processor.h>
+
+struct cpu_hw_events {
+	struct perf_event	*events[MAX_HWEVENTS];
+	unsigned long		used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
+	unsigned long		active_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
+};
+
+DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
+
+static struct sh_pmu *sh_pmu __read_mostly;
+
+/* Number of perf_events counting hardware events */
+static atomic_t num_events;
+/* Used to avoid races in calling reserve/release_pmc_hardware */
+static DEFINE_MUTEX(pmc_reserve_mutex);
+
+/*
+ * Stub these out for now, do something more profound later.
+ */
+int reserve_pmc_hardware(void)
+{
+	return 0;
+}
+
+void release_pmc_hardware(void)
+{
+}
+
+static inline int sh_pmu_initialized(void)
+{
+	return !!sh_pmu;
+}
+
+/*
+ * Release the PMU if this is the last perf_event.
+ */
+static void hw_perf_event_destroy(struct perf_event *event)
+{
+	if (!atomic_add_unless(&num_events, -1, 1)) {
+		mutex_lock(&pmc_reserve_mutex);
+		if (atomic_dec_return(&num_events) == 0)
+			release_pmc_hardware();
+		mutex_unlock(&pmc_reserve_mutex);
+	}
+}
+
+static int hw_perf_cache_event(int config, int *evp)
+{
+	unsigned long type, op, result;
+	int ev;
+
+	if (!sh_pmu->cache_events)
+		return -EINVAL;
+
+	/* unpack config */
+	type = config & 0xff;
+	op = (config >> 8) & 0xff;
+	result = (config >> 16) & 0xff;
+
+	if (type >= PERF_COUNT_HW_CACHE_MAX ||
+	    op >= PERF_COUNT_HW_CACHE_OP_MAX ||
+	    result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+		return -EINVAL;
+
+	ev = (*sh_pmu->cache_events)[type][op][result];
+	if (ev == 0)
+		return -EOPNOTSUPP;
+	if (ev == -1)
+		return -EINVAL;
+	*evp = ev;
+	return 0;
+}
+
+static int __hw_perf_event_init(struct perf_event *event)
+{
+	struct perf_event_attr *attr = &event->attr;
+	struct hw_perf_event *hwc = &event->hw;
+	int config = -1;
+	int err;
+
+	if (!sh_pmu_initialized())
+		return -ENODEV;
+
+	/*
+	 * See if we need to reserve the counter.
+	 *
+	 * If no events are currently in use, then we have to take a
+	 * mutex to ensure that we don't race with another task doing
+	 * reserve_pmc_hardware or release_pmc_hardware.
+	 */
+	err = 0;
+	if (!atomic_inc_not_zero(&num_events)) {
+		mutex_lock(&pmc_reserve_mutex);
+		if (atomic_read(&num_events) == 0 &&
+		    reserve_pmc_hardware())
+			err = -EBUSY;
+		else
+			atomic_inc(&num_events);
+		mutex_unlock(&pmc_reserve_mutex);
+	}
+
+	if (err)
+		return err;
+
+	event->destroy = hw_perf_event_destroy;
+
+	switch (attr->type) {
+	case PERF_TYPE_RAW:
+		config = attr->config & sh_pmu->raw_event_mask;
+		break;
+	case PERF_TYPE_HW_CACHE:
+		err = hw_perf_cache_event(attr->config, &config);
+		if (err)
+			return err;
+		break;
+	case PERF_TYPE_HARDWARE:
+		if (attr->config >= sh_pmu->max_events)
+			return -EINVAL;
+
+		config = sh_pmu->event_map(attr->config);
+		break;
+	}
+
+	if (config == -1)
+		return -EINVAL;
+
+	hwc->config |= config;
+
+	return 0;
+}
+
+static void sh_perf_event_update(struct perf_event *event,
+				   struct hw_perf_event *hwc, int idx)
+{
+	u64 prev_raw_count, new_raw_count;
+	s64 delta;
+	int shift = 0;
+
+	/*
+	 * Depending on the counter configuration, they may or may not
+	 * be chained, in which case the previous counter value can be
+	 * updated underneath us if the lower-half overflows.
+	 *
+	 * Our tactic to handle this is to first atomically read and
+	 * exchange a new raw count - then add that new-prev delta
+	 * count to the generic counter atomically.
+	 *
+	 * As there is no interrupt associated with the overflow events,
+	 * this is the simplest approach for maintaining consistency.
+	 */
+again:
+	prev_raw_count = local64_read(&hwc->prev_count);
+	new_raw_count = sh_pmu->read(idx);
+
+	if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+			     new_raw_count) != prev_raw_count)
+		goto again;
+
+	/*
+	 * Now we have the new raw value and have updated the prev
+	 * timestamp already. We can now calculate the elapsed delta
+	 * (counter-)time and add that to the generic counter.
+	 *
+	 * Careful, not all hw sign-extends above the physical width
+	 * of the count.
+	 */
+	delta = (new_raw_count << shift) - (prev_raw_count << shift);
+	delta >>= shift;
+
+	local64_add(delta, &event->count);
+}
+
+static void sh_pmu_stop(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+
+	if (!(event->hw.state & PERF_HES_STOPPED)) {
+		sh_pmu->disable(hwc, idx);
+		cpuc->events[idx] = NULL;
+		event->hw.state |= PERF_HES_STOPPED;
+	}
+
+	if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) {
+		sh_perf_event_update(event, &event->hw, idx);
+		event->hw.state |= PERF_HES_UPTODATE;
+	}
+}
+
+static void sh_pmu_start(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+
+	if (WARN_ON_ONCE(idx == -1))
+		return;
+
+	if (flags & PERF_EF_RELOAD)
+		WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
+
+	cpuc->events[idx] = event;
+	event->hw.state = 0;
+	sh_pmu->enable(hwc, idx);
+}
+
+static void sh_pmu_del(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+
+	sh_pmu_stop(event, PERF_EF_UPDATE);
+	__clear_bit(event->hw.idx, cpuc->used_mask);
+
+	perf_event_update_userpage(event);
+}
+
+static int sh_pmu_add(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+	int ret = -EAGAIN;
+
+	perf_pmu_disable(event->pmu);
+
+	if (__test_and_set_bit(idx, cpuc->used_mask)) {
+		idx = find_first_zero_bit(cpuc->used_mask, sh_pmu->num_events);
+		if (idx == sh_pmu->num_events)
+			goto out;
+
+		__set_bit(idx, cpuc->used_mask);
+		hwc->idx = idx;
+	}
+
+	sh_pmu->disable(hwc, idx);
+
+	event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+	if (flags & PERF_EF_START)
+		sh_pmu_start(event, PERF_EF_RELOAD);
+
+	perf_event_update_userpage(event);
+	ret = 0;
+out:
+	perf_pmu_enable(event->pmu);
+	return ret;
+}
+
+static void sh_pmu_read(struct perf_event *event)
+{
+	sh_perf_event_update(event, &event->hw, event->hw.idx);
+}
+
+static int sh_pmu_event_init(struct perf_event *event)
+{
+	int err;
+
+	/* does not support taken branch sampling */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	switch (event->attr.type) {
+	case PERF_TYPE_RAW:
+	case PERF_TYPE_HW_CACHE:
+	case PERF_TYPE_HARDWARE:
+		err = __hw_perf_event_init(event);
+		break;
+
+	default:
+		return -ENOENT;
+	}
+
+	if (unlikely(err)) {
+		if (event->destroy)
+			event->destroy(event);
+	}
+
+	return err;
+}
+
+static void sh_pmu_enable(struct pmu *pmu)
+{
+	if (!sh_pmu_initialized())
+		return;
+
+	sh_pmu->enable_all();
+}
+
+static void sh_pmu_disable(struct pmu *pmu)
+{
+	if (!sh_pmu_initialized())
+		return;
+
+	sh_pmu->disable_all();
+}
+
+static struct pmu pmu = {
+	.pmu_enable	= sh_pmu_enable,
+	.pmu_disable	= sh_pmu_disable,
+	.event_init	= sh_pmu_event_init,
+	.add		= sh_pmu_add,
+	.del		= sh_pmu_del,
+	.start		= sh_pmu_start,
+	.stop		= sh_pmu_stop,
+	.read		= sh_pmu_read,
+};
+
+static int sh_pmu_prepare_cpu(unsigned int cpu)
+{
+	struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
+
+	memset(cpuhw, 0, sizeof(struct cpu_hw_events));
+	return 0;
+}
+
+int register_sh_pmu(struct sh_pmu *_pmu)
+{
+	if (sh_pmu)
+		return -EBUSY;
+	sh_pmu = _pmu;
+
+	pr_info("Performance Events: %s support registered\n", _pmu->name);
+
+	/*
+	 * All of the on-chip counters are "limited", in that they have
+	 * no interrupts, and are therefore unable to do sampling without
+	 * further work and timer assistance.
+	 */
+	pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+
+	WARN_ON(_pmu->num_events > MAX_HWEVENTS);
+
+	perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
+	cpuhp_setup_state(CPUHP_PERF_SUPERH, "PERF_SUPERH", sh_pmu_prepare_cpu,
+			  NULL);
+	return 0;
+}