1 files changed, 524 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
new file mode 100644
index 000000000..567f46ca2
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(C) 2015 Linaro Limited. All rights reserved.
+ * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
+ */
+
+#include <linux/coresight.h>
+#include <linux/coresight-pmu.h>
+#include <linux/cpumask.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/perf_event.h>
+#include <linux/percpu-defs.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+#include "coresight-etm-perf.h"
+#include "coresight-priv.h"
+
+static struct pmu etm_pmu;
+static bool etm_perf_up;
+
+/**
+ * struct etm_event_data - Coresight specifics associated to an event
+ * @work:		Handle to free allocated memory outside IRQ context.
+ * @mask:		Hold the CPU(s) this event was set for.
+ * @snk_config:		The sink configuration.
+ * @path:		An array of path, each slot for one CPU.
+ */
+struct etm_event_data {
+	struct work_struct work;
+	cpumask_t mask;
+	void *snk_config;
+	struct list_head * __percpu *path;
+};
+
+static DEFINE_PER_CPU(struct perf_output_handle, ctx_handle);
+static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
+
+/* ETMv3.5/PTM's ETMCR is 'config' */
+PMU_FORMAT_ATTR(cycacc,		"config:" __stringify(ETM_OPT_CYCACC));
+PMU_FORMAT_ATTR(timestamp,	"config:" __stringify(ETM_OPT_TS));
+PMU_FORMAT_ATTR(retstack,	"config:" __stringify(ETM_OPT_RETSTK));
+
+static struct attribute *etm_config_formats_attr[] = {
+	&format_attr_cycacc.attr,
+	&format_attr_timestamp.attr,
+	&format_attr_retstack.attr,
+	NULL,
+};
+
+static const struct attribute_group etm_pmu_format_group = {
+	.name   = "format",
+	.attrs  = etm_config_formats_attr,
+};
+
+static const struct attribute_group *etm_pmu_attr_groups[] = {
+	&etm_pmu_format_group,
+	NULL,
+};
+
+static inline struct list_head **
+etm_event_cpu_path_ptr(struct etm_event_data *data, int cpu)
+{
+	return per_cpu_ptr(data->path, cpu);
+}
+
+static inline struct list_head *
+etm_event_cpu_path(struct etm_event_data *data, int cpu)
+{
+	return *etm_event_cpu_path_ptr(data, cpu);
+}
+
+static void etm_event_read(struct perf_event *event) {}
+
+static int etm_addr_filters_alloc(struct perf_event *event)
+{
+	struct etm_filters *filters;
+	int node = event->cpu == -1 ? -1 : cpu_to_node(event->cpu);
+
+	filters = kzalloc_node(sizeof(struct etm_filters), GFP_KERNEL, node);
+	if (!filters)
+		return -ENOMEM;
+
+	if (event->parent)
+		memcpy(filters, event->parent->hw.addr_filters,
+		       sizeof(*filters));
+
+	event->hw.addr_filters = filters;
+
+	return 0;
+}
+
+static void etm_event_destroy(struct perf_event *event)
+{
+	kfree(event->hw.addr_filters);
+	event->hw.addr_filters = NULL;
+}
+
+static int etm_event_init(struct perf_event *event)
+{
+	int ret = 0;
+
+	if (event->attr.type != etm_pmu.type) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	ret = etm_addr_filters_alloc(event);
+	if (ret)
+		goto out;
+
+	event->destroy = etm_event_destroy;
+out:
+	return ret;
+}
+
+static void free_event_data(struct work_struct *work)
+{
+	int cpu;
+	cpumask_t *mask;
+	struct etm_event_data *event_data;
+	struct coresight_device *sink;
+
+	event_data = container_of(work, struct etm_event_data, work);
+	mask = &event_data->mask;
+	/*
+	 * First deal with the sink configuration.  See comment in
+	 * etm_setup_aux() about why we take the first available path.
+	 */
+	if (event_data->snk_config) {
+		cpu = cpumask_first(mask);
+		sink = coresight_get_sink(etm_event_cpu_path(event_data, cpu));
+		if (sink_ops(sink)->free_buffer)
+			sink_ops(sink)->free_buffer(event_data->snk_config);
+	}
+
+	for_each_cpu(cpu, mask) {
+		struct list_head **ppath;
+
+		ppath = etm_event_cpu_path_ptr(event_data, cpu);
+		if (!(IS_ERR_OR_NULL(*ppath)))
+			coresight_release_path(*ppath);
+		*ppath = NULL;
+	}
+
+	free_percpu(event_data->path);
+	kfree(event_data);
+}
+
+static void *alloc_event_data(int cpu)
+{
+	cpumask_t *mask;
+	struct etm_event_data *event_data;
+
+	/* First get memory for the session's data */
+	event_data = kzalloc(sizeof(struct etm_event_data), GFP_KERNEL);
+	if (!event_data)
+		return NULL;
+
+	/* Make sure nothing disappears under us */
+	get_online_cpus();
+
+	mask = &event_data->mask;
+	if (cpu != -1)
+		cpumask_set_cpu(cpu, mask);
+	else
+		cpumask_copy(mask, cpu_online_mask);
+	put_online_cpus();
+
+	/*
+	 * Each CPU has a single path between source and destination.  As such
+	 * allocate an array using CPU numbers as indexes.  That way a path
+	 * for any CPU can easily be accessed at any given time.  We proceed
+	 * the same way for sessions involving a single CPU.  The cost of
+	 * unused memory when dealing with single CPU trace scenarios is small
+	 * compared to the cost of searching through an optimized array.
+	 */
+	event_data->path = alloc_percpu(struct list_head *);
+
+	if (!event_data->path) {
+		kfree(event_data);
+		return NULL;
+	}
+
+	return event_data;
+}
+
+static void etm_free_aux(void *data)
+{
+	struct etm_event_data *event_data = data;
+
+	schedule_work(&event_data->work);
+}
+
+static void *etm_setup_aux(struct perf_event *event, void **pages,
+			   int nr_pages, bool overwrite)
+{
+	int cpu = event->cpu;
+	cpumask_t *mask;
+	struct coresight_device *sink;
+	struct etm_event_data *event_data = NULL;
+
+	event_data = alloc_event_data(cpu);
+	if (!event_data)
+		return NULL;
+	INIT_WORK(&event_data->work, free_event_data);
+
+	/*
+	 * In theory nothing prevent tracers in a trace session from being
+	 * associated with different sinks, nor having a sink per tracer.  But
+	 * until we have HW with this kind of topology we need to assume tracers
+	 * in a trace session are using the same sink.  Therefore go through
+	 * the coresight bus and pick the first enabled sink.
+	 *
+	 * When operated from sysFS users are responsible to enable the sink
+	 * while from perf, the perf tools will do it based on the choice made
+	 * on the cmd line.  As such the "enable_sink" flag in sysFS is reset.
+	 */
+	sink = coresight_get_enabled_sink(true);
+	if (!sink)
+		goto err;
+
+	mask = &event_data->mask;
+
+	/* Setup the path for each CPU in a trace session */
+	for_each_cpu(cpu, mask) {
+		struct list_head *path;
+		struct coresight_device *csdev;
+
+		csdev = per_cpu(csdev_src, cpu);
+		if (!csdev)
+			goto err;
+
+		/*
+		 * Building a path doesn't enable it, it simply builds a
+		 * list of devices from source to sink that can be
+		 * referenced later when the path is actually needed.
+		 */
+		path = coresight_build_path(csdev, sink);
+		if (IS_ERR(path))
+			goto err;
+
+		*etm_event_cpu_path_ptr(event_data, cpu) = path;
+	}
+
+	if (!sink_ops(sink)->alloc_buffer)
+		goto err;
+
+	cpu = cpumask_first(mask);
+	/* Get the AUX specific data from the sink buffer */
+	event_data->snk_config =
+			sink_ops(sink)->alloc_buffer(sink, cpu, pages,
+						     nr_pages, overwrite);
+	if (!event_data->snk_config)
+		goto err;
+
+out:
+	return event_data;
+
+err:
+	etm_free_aux(event_data);
+	event_data = NULL;
+	goto out;
+}
+
+static void etm_event_start(struct perf_event *event, int flags)
+{
+	int cpu = smp_processor_id();
+	struct etm_event_data *event_data;
+	struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
+	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
+	struct list_head *path;
+
+	if (!csdev)
+		goto fail;
+
+	/*
+	 * Deal with the ring buffer API and get a handle on the
+	 * session's information.
+	 */
+	event_data = perf_aux_output_begin(handle, event);
+	if (!event_data)
+		goto fail;
+
+	path = etm_event_cpu_path(event_data, cpu);
+	/* We need a sink, no need to continue without one */
+	sink = coresight_get_sink(path);
+	if (WARN_ON_ONCE(!sink || !sink_ops(sink)->set_buffer))
+		goto fail_end_stop;
+
+	/* Configure the sink */
+	if (sink_ops(sink)->set_buffer(sink, handle,
+				       event_data->snk_config))
+		goto fail_end_stop;
+
+	/* Nothing will happen without a path */
+	if (coresight_enable_path(path, CS_MODE_PERF))
+		goto fail_end_stop;
+
+	/* Tell the perf core the event is alive */
+	event->hw.state = 0;
+
+	/* Finally enable the tracer */
+	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
+		goto fail_disable_path;
+
+out:
+	return;
+
+fail_disable_path:
+	coresight_disable_path(path);
+fail_end_stop:
+	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+	perf_aux_output_end(handle, 0);
+fail:
+	event->hw.state = PERF_HES_STOPPED;
+	goto out;
+}
+
+static void etm_event_stop(struct perf_event *event, int mode)
+{
+	int cpu = smp_processor_id();
+	unsigned long size;
+	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
+	struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
+	struct etm_event_data *event_data = perf_get_aux(handle);
+	struct list_head *path;
+
+	if (event->hw.state == PERF_HES_STOPPED)
+		return;
+
+	if (!csdev)
+		return;
+
+	path = etm_event_cpu_path(event_data, cpu);
+	if (!path)
+		return;
+
+	sink = coresight_get_sink(path);
+	if (!sink)
+		return;
+
+	/* stop tracer */
+	source_ops(csdev)->disable(csdev, event);
+
+	/* tell the core */
+	event->hw.state = PERF_HES_STOPPED;
+
+	if (mode & PERF_EF_UPDATE) {
+		if (WARN_ON_ONCE(handle->event != event))
+			return;
+
+		/* update trace information */
+		if (!sink_ops(sink)->update_buffer)
+			return;
+
+		sink_ops(sink)->update_buffer(sink, handle,
+					      event_data->snk_config);
+
+		if (!sink_ops(sink)->reset_buffer)
+			return;
+
+		size = sink_ops(sink)->reset_buffer(sink, handle,
+						    event_data->snk_config);
+
+		perf_aux_output_end(handle, size);
+	}
+
+	/* Disabling the path make its elements available to other sessions */
+	coresight_disable_path(path);
+}
+
+static int etm_event_add(struct perf_event *event, int mode)
+{
+	int ret = 0;
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (mode & PERF_EF_START) {
+		etm_event_start(event, 0);
+		if (hwc->state & PERF_HES_STOPPED)
+			ret = -EINVAL;
+	} else {
+		hwc->state = PERF_HES_STOPPED;
+	}
+
+	return ret;
+}
+
+static void etm_event_del(struct perf_event *event, int mode)
+{
+	etm_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int etm_addr_filters_validate(struct list_head *filters)
+{
+	bool range = false, address = false;
+	int index = 0;
+	struct perf_addr_filter *filter;
+
+	list_for_each_entry(filter, filters, entry) {
+		/*
+		 * No need to go further if there's no more
+		 * room for filters.
+		 */
+		if (++index > ETM_ADDR_CMP_MAX)
+			return -EOPNOTSUPP;
+
+		/* filter::size==0 means single address trigger */
+		if (filter->size) {
+			/*
+			 * The existing code relies on START/STOP filters
+			 * being address filters.
+			 */
+			if (filter->action == PERF_ADDR_FILTER_ACTION_START ||
+			    filter->action == PERF_ADDR_FILTER_ACTION_STOP)
+				return -EOPNOTSUPP;
+
+			range = true;
+		} else
+			address = true;
+
+		/*
+		 * At this time we don't allow range and start/stop filtering
+		 * to cohabitate, they have to be mutually exclusive.
+		 */
+		if (range && address)
+			return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static void etm_addr_filters_sync(struct perf_event *event)
+{
+	struct perf_addr_filters_head *head = perf_event_addr_filters(event);
+	unsigned long start, stop;
+	struct perf_addr_filter_range *fr = event->addr_filter_ranges;
+	struct etm_filters *filters = event->hw.addr_filters;
+	struct etm_filter *etm_filter;
+	struct perf_addr_filter *filter;
+	int i = 0;
+
+	list_for_each_entry(filter, &head->list, entry) {
+		start = fr[i].start;
+		stop = start + fr[i].size;
+		etm_filter = &filters->etm_filter[i];
+
+		switch (filter->action) {
+		case PERF_ADDR_FILTER_ACTION_FILTER:
+			etm_filter->start_addr = start;
+			etm_filter->stop_addr = stop;
+			etm_filter->type = ETM_ADDR_TYPE_RANGE;
+			break;
+		case PERF_ADDR_FILTER_ACTION_START:
+			etm_filter->start_addr = start;
+			etm_filter->type = ETM_ADDR_TYPE_START;
+			break;
+		case PERF_ADDR_FILTER_ACTION_STOP:
+			etm_filter->stop_addr = stop;
+			etm_filter->type = ETM_ADDR_TYPE_STOP;
+			break;
+		}
+		i++;
+	}
+
+	filters->nr_filters = i;
+}
+
+int etm_perf_symlink(struct coresight_device *csdev, bool link)
+{
+	char entry[sizeof("cpu9999999")];
+	int ret = 0, cpu = source_ops(csdev)->cpu_id(csdev);
+	struct device *pmu_dev = etm_pmu.dev;
+	struct device *cs_dev = &csdev->dev;
+
+	sprintf(entry, "cpu%d", cpu);
+
+	if (!etm_perf_up)
+		return -EPROBE_DEFER;
+
+	if (link) {
+		ret = sysfs_create_link(&pmu_dev->kobj, &cs_dev->kobj, entry);
+		if (ret)
+			return ret;
+		per_cpu(csdev_src, cpu) = csdev;
+	} else {
+		sysfs_remove_link(&pmu_dev->kobj, entry);
+		per_cpu(csdev_src, cpu) = NULL;
+	}
+
+	return 0;
+}
+
+static int __init etm_perf_init(void)
+{
+	int ret;
+
+	etm_pmu.capabilities		= PERF_PMU_CAP_EXCLUSIVE;
+
+	etm_pmu.attr_groups		= etm_pmu_attr_groups;
+	etm_pmu.task_ctx_nr		= perf_sw_context;
+	etm_pmu.read			= etm_event_read;
+	etm_pmu.event_init		= etm_event_init;
+	etm_pmu.setup_aux		= etm_setup_aux;
+	etm_pmu.free_aux		= etm_free_aux;
+	etm_pmu.start			= etm_event_start;
+	etm_pmu.stop			= etm_event_stop;
+	etm_pmu.add			= etm_event_add;
+	etm_pmu.del			= etm_event_del;
+	etm_pmu.addr_filters_sync	= etm_addr_filters_sync;
+	etm_pmu.addr_filters_validate	= etm_addr_filters_validate;
+	etm_pmu.nr_addr_filters		= ETM_ADDR_CMP_MAX;
+
+	ret = perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1);
+	if (ret == 0)
+		etm_perf_up = true;
+
+	return ret;
+}
+device_initcall(etm_perf_init);