Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 885 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..f9a0ee49d
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -0,0 +1,885 @@
+// 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/stringhash.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+#include "coresight-config.h"
+#include "coresight-etm-perf.h"
+#include "coresight-priv.h"
+#include "coresight-syscfg.h"
+
+static struct pmu etm_pmu;
+static bool etm_perf_up;
+
+/*
+ * An ETM context for a running event includes the perf aux handle
+ * and aux_data. For ETM, the aux_data (etm_event_data), consists of
+ * the trace path and the sink configuration. The event data is accessible
+ * via perf_get_aux(handle). However, a sink could "end" a perf output
+ * handle via the IRQ handler. And if the "sink" encounters a failure
+ * to "begin" another session (e.g due to lack of space in the buffer),
+ * the handle will be cleared. Thus, the event_data may not be accessible
+ * from the handle when we get to the etm_event_stop(), which is required
+ * for stopping the trace path. The event_data is guaranteed to stay alive
+ * until "free_aux()", which cannot happen as long as the event is active on
+ * the ETM. Thus the event_data for the session must be part of the ETM context
+ * to make sure we can disable the trace path.
+ */
+struct etm_ctxt {
+	struct perf_output_handle handle;
+	struct etm_event_data *event_data;
+};
+
+static DEFINE_PER_CPU(struct etm_ctxt, etm_ctxt);
+static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
+
+/*
+ * The PMU formats were orignally for ETMv3.5/PTM's ETMCR 'config';
+ * now take them as general formats and apply on all ETMs.
+ */
+PMU_FORMAT_ATTR(branch_broadcast, "config:"__stringify(ETM_OPT_BRANCH_BROADCAST));
+PMU_FORMAT_ATTR(cycacc,		"config:" __stringify(ETM_OPT_CYCACC));
+/* contextid1 enables tracing CONTEXTIDR_EL1 for ETMv4 */
+PMU_FORMAT_ATTR(contextid1,	"config:" __stringify(ETM_OPT_CTXTID));
+/* contextid2 enables tracing CONTEXTIDR_EL2 for ETMv4 */
+PMU_FORMAT_ATTR(contextid2,	"config:" __stringify(ETM_OPT_CTXTID2));
+PMU_FORMAT_ATTR(timestamp,	"config:" __stringify(ETM_OPT_TS));
+PMU_FORMAT_ATTR(retstack,	"config:" __stringify(ETM_OPT_RETSTK));
+/* preset - if sink ID is used as a configuration selector */
+PMU_FORMAT_ATTR(preset,		"config:0-3");
+/* Sink ID - same for all ETMs */
+PMU_FORMAT_ATTR(sinkid,		"config2:0-31");
+/* config ID - set if a system configuration is selected */
+PMU_FORMAT_ATTR(configid,	"config2:32-63");
+
+
+/*
+ * contextid always traces the "PID".  The PID is in CONTEXTIDR_EL1
+ * when the kernel is running at EL1; when the kernel is at EL2,
+ * the PID is in CONTEXTIDR_EL2.
+ */
+static ssize_t format_attr_contextid_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *page)
+{
+	int pid_fmt = ETM_OPT_CTXTID;
+
+#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)
+	pid_fmt = is_kernel_in_hyp_mode() ? ETM_OPT_CTXTID2 : ETM_OPT_CTXTID;
+#endif
+	return sprintf(page, "config:%d\n", pid_fmt);
+}
+
+static struct device_attribute format_attr_contextid =
+	__ATTR(contextid, 0444, format_attr_contextid_show, NULL);
+
+static struct attribute *etm_config_formats_attr[] = {
+	&format_attr_cycacc.attr,
+	&format_attr_contextid.attr,
+	&format_attr_contextid1.attr,
+	&format_attr_contextid2.attr,
+	&format_attr_timestamp.attr,
+	&format_attr_retstack.attr,
+	&format_attr_sinkid.attr,
+	&format_attr_preset.attr,
+	&format_attr_configid.attr,
+	&format_attr_branch_broadcast.attr,
+	NULL,
+};
+
+static const struct attribute_group etm_pmu_format_group = {
+	.name   = "format",
+	.attrs  = etm_config_formats_attr,
+};
+
+static struct attribute *etm_config_sinks_attr[] = {
+	NULL,
+};
+
+static const struct attribute_group etm_pmu_sinks_group = {
+	.name   = "sinks",
+	.attrs  = etm_config_sinks_attr,
+};
+
+static struct attribute *etm_config_events_attr[] = {
+	NULL,
+};
+
+static const struct attribute_group etm_pmu_events_group = {
+	.name   = "events",
+	.attrs  = etm_config_events_attr,
+};
+
+static const struct attribute_group *etm_pmu_attr_groups[] = {
+	&etm_pmu_format_group,
+	&etm_pmu_sinks_group,
+	&etm_pmu_events_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_sink_buffer(struct etm_event_data *event_data)
+{
+	int cpu;
+	cpumask_t *mask = &event_data->mask;
+	struct coresight_device *sink;
+
+	if (!event_data->snk_config)
+		return;
+
+	if (WARN_ON(cpumask_empty(mask)))
+		return;
+
+	cpu = cpumask_first(mask);
+	sink = coresight_get_sink(etm_event_cpu_path(event_data, cpu));
+	sink_ops(sink)->free_buffer(event_data->snk_config);
+}
+
+static void free_event_data(struct work_struct *work)
+{
+	int cpu;
+	cpumask_t *mask;
+	struct etm_event_data *event_data;
+
+	event_data = container_of(work, struct etm_event_data, work);
+	mask = &event_data->mask;
+
+	/* Free the sink buffers, if there are any */
+	free_sink_buffer(event_data);
+
+	/* clear any configuration we were using */
+	if (event_data->cfg_hash)
+		cscfg_deactivate_config(event_data->cfg_hash);
+
+	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;
+
+
+	mask = &event_data->mask;
+	if (cpu != -1)
+		cpumask_set_cpu(cpu, mask);
+	else
+		cpumask_copy(mask, cpu_present_mask);
+
+	/*
+	 * 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);
+}
+
+/*
+ * Check if two given sinks are compatible with each other,
+ * so that they can use the same sink buffers, when an event
+ * moves around.
+ */
+static bool sinks_compatible(struct coresight_device *a,
+			     struct coresight_device *b)
+{
+	if (!a || !b)
+		return false;
+	/*
+	 * If the sinks are of the same subtype and driven
+	 * by the same driver, we can use the same buffer
+	 * on these sinks.
+	 */
+	return (a->subtype.sink_subtype == b->subtype.sink_subtype) &&
+	       (sink_ops(a) == sink_ops(b));
+}
+
+static void *etm_setup_aux(struct perf_event *event, void **pages,
+			   int nr_pages, bool overwrite)
+{
+	u32 id, cfg_hash;
+	int cpu = event->cpu;
+	cpumask_t *mask;
+	struct coresight_device *sink = NULL;
+	struct coresight_device *user_sink = NULL, *last_sink = NULL;
+	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);
+
+	/* First get the selected sink from user space. */
+	if (event->attr.config2 & GENMASK_ULL(31, 0)) {
+		id = (u32)event->attr.config2;
+		sink = user_sink = coresight_get_sink_by_id(id);
+	}
+
+	/* check if user wants a coresight configuration selected */
+	cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32);
+	if (cfg_hash) {
+		if (cscfg_activate_config(cfg_hash))
+			goto err;
+		event_data->cfg_hash = cfg_hash;
+	}
+
+	mask = &event_data->mask;
+
+	/*
+	 * Setup the path for each CPU in a trace session. We try to build
+	 * trace path for each CPU in the mask. If we don't find an ETM
+	 * for the CPU or fail to build a path, we clear the CPU from the
+	 * mask and continue with the rest. If ever we try to trace on those
+	 * CPUs, we can handle it and fail the session.
+	 */
+	for_each_cpu(cpu, mask) {
+		struct list_head *path;
+		struct coresight_device *csdev;
+
+		csdev = per_cpu(csdev_src, cpu);
+		/*
+		 * If there is no ETM associated with this CPU clear it from
+		 * the mask and continue with the rest. If ever we try to trace
+		 * on this CPU, we handle it accordingly.
+		 */
+		if (!csdev) {
+			cpumask_clear_cpu(cpu, mask);
+			continue;
+		}
+
+		/*
+		 * No sink provided - look for a default sink for all the ETMs,
+		 * where this event can be scheduled.
+		 * We allocate the sink specific buffers only once for this
+		 * event. If the ETMs have different default sink devices, we
+		 * can only use a single "type" of sink as the event can carry
+		 * only one sink specific buffer. Thus we have to make sure
+		 * that the sinks are of the same type and driven by the same
+		 * driver, as the one we allocate the buffer for. As such
+		 * we choose the first sink and check if the remaining ETMs
+		 * have a compatible default sink. We don't trace on a CPU
+		 * if the sink is not compatible.
+		 */
+		if (!user_sink) {
+			/* Find the default sink for this ETM */
+			sink = coresight_find_default_sink(csdev);
+			if (!sink) {
+				cpumask_clear_cpu(cpu, mask);
+				continue;
+			}
+
+			/* Check if this sink compatible with the last sink */
+			if (last_sink && !sinks_compatible(last_sink, sink)) {
+				cpumask_clear_cpu(cpu, mask);
+				continue;
+			}
+			last_sink = sink;
+		}
+
+		/*
+		 * 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)) {
+			cpumask_clear_cpu(cpu, mask);
+			continue;
+		}
+
+		*etm_event_cpu_path_ptr(event_data, cpu) = path;
+	}
+
+	/* no sink found for any CPU - cannot trace */
+	if (!sink)
+		goto err;
+
+	/* If we don't have any CPUs ready for tracing, abort */
+	cpu = cpumask_first(mask);
+	if (cpu >= nr_cpu_ids)
+		goto err;
+
+	if (!sink_ops(sink)->alloc_buffer || !sink_ops(sink)->free_buffer)
+		goto err;
+
+	/*
+	 * Allocate the sink buffer for this session. All the sinks
+	 * where this event can be scheduled are ensured to be of the
+	 * same type. Thus the same sink configuration is used by the
+	 * sinks.
+	 */
+	event_data->snk_config =
+			sink_ops(sink)->alloc_buffer(sink, event, 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 etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
+	struct perf_output_handle *handle = &ctxt->handle;
+	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
+	struct list_head *path;
+
+	if (!csdev)
+		goto fail;
+
+	/* Have we messed up our tracking ? */
+	if (WARN_ON(ctxt->event_data))
+		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;
+
+	/*
+	 * Check if this ETM is allowed to trace, as decided
+	 * at etm_setup_aux(). This could be due to an unreachable
+	 * sink from this ETM. We can't do much in this case if
+	 * the sink was specified or hinted to the driver. For
+	 * now, simply don't record anything on this ETM.
+	 *
+	 * As such we pretend that everything is fine, and let
+	 * it continue without actually tracing. The event could
+	 * continue tracing when it moves to a CPU where it is
+	 * reachable to a sink.
+	 */
+	if (!cpumask_test_cpu(cpu, &event_data->mask))
+		goto out;
+
+	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))
+		goto fail_end_stop;
+
+	/* Nothing will happen without a path */
+	if (coresight_enable_path(path, CS_MODE_PERF, handle))
+		goto fail_end_stop;
+
+	/* Finally enable the tracer */
+	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
+		goto fail_disable_path;
+
+out:
+	/* Tell the perf core the event is alive */
+	event->hw.state = 0;
+	/* Save the event_data for this ETM */
+	ctxt->event_data = event_data;
+	return;
+
+fail_disable_path:
+	coresight_disable_path(path);
+fail_end_stop:
+	/*
+	 * Check if the handle is still associated with the event,
+	 * to handle cases where if the sink failed to start the
+	 * trace and TRUNCATED the handle already.
+	 */
+	if (READ_ONCE(handle->event)) {
+		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+		perf_aux_output_end(handle, 0);
+	}
+fail:
+	event->hw.state = PERF_HES_STOPPED;
+	return;
+}
+
+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 etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
+	struct perf_output_handle *handle = &ctxt->handle;
+	struct etm_event_data *event_data;
+	struct list_head *path;
+
+	/*
+	 * If we still have access to the event_data via handle,
+	 * confirm that we haven't messed up the tracking.
+	 */
+	if (handle->event &&
+	    WARN_ON(perf_get_aux(handle) != ctxt->event_data))
+		return;
+
+	event_data = ctxt->event_data;
+	/* Clear the event_data as this ETM is stopping the trace. */
+	ctxt->event_data = NULL;
+
+	if (event->hw.state == PERF_HES_STOPPED)
+		return;
+
+	/* We must have a valid event_data for a running event */
+	if (WARN_ON(!event_data))
+		return;
+
+	/*
+	 * Check if this ETM was allowed to trace, as decided at
+	 * etm_setup_aux(). If it wasn't allowed to trace, then
+	 * nothing needs to be torn down other than outputting a
+	 * zero sized record.
+	 */
+	if (handle->event && (mode & PERF_EF_UPDATE) &&
+	    !cpumask_test_cpu(cpu, &event_data->mask)) {
+		event->hw.state = PERF_HES_STOPPED;
+		perf_aux_output_end(handle, 0);
+		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 the handle is not bound to an event anymore
+	 * (e.g, the sink driver was unable to restart the
+	 * handle due to lack of buffer space), we don't
+	 * have to do anything here.
+	 */
+	if (handle->event && (mode & PERF_EF_UPDATE)) {
+		if (WARN_ON_ONCE(handle->event != event))
+			return;
+
+		/* update trace information */
+		if (!sink_ops(sink)->update_buffer)
+			return;
+
+		size = sink_ops(sink)->update_buffer(sink, handle,
+					      event_data->snk_config);
+		/*
+		 * Make sure the handle is still valid as the
+		 * sink could have closed it from an IRQ.
+		 * The sink driver must handle the race with
+		 * update_buffer() and IRQ. Thus either we
+		 * should get a valid handle and valid size
+		 * (which may be 0).
+		 *
+		 * But we should never get a non-zero size with
+		 * an invalid handle.
+		 */
+		if (READ_ONCE(handle->event))
+			perf_aux_output_end(handle, size);
+		else
+			WARN_ON(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;
+}
+EXPORT_SYMBOL_GPL(etm_perf_symlink);
+
+static ssize_t etm_perf_sink_name_show(struct device *dev,
+				       struct device_attribute *dattr,
+				       char *buf)
+{
+	struct dev_ext_attribute *ea;
+
+	ea = container_of(dattr, struct dev_ext_attribute, attr);
+	return scnprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)(ea->var));
+}
+
+static struct dev_ext_attribute *
+etm_perf_add_symlink_group(struct device *dev, const char *name, const char *group_name)
+{
+	struct dev_ext_attribute *ea;
+	unsigned long hash;
+	int ret;
+	struct device *pmu_dev = etm_pmu.dev;
+
+	if (!etm_perf_up)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	ea = devm_kzalloc(dev, sizeof(*ea), GFP_KERNEL);
+	if (!ea)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * If this function is called adding a sink then the hash is used for
+	 * sink selection - see function coresight_get_sink_by_id().
+	 * If adding a configuration then the hash is used for selection in
+	 * cscfg_activate_config()
+	 */
+	hash = hashlen_hash(hashlen_string(NULL, name));
+
+	sysfs_attr_init(&ea->attr.attr);
+	ea->attr.attr.name = devm_kstrdup(dev, name, GFP_KERNEL);
+	if (!ea->attr.attr.name)
+		return ERR_PTR(-ENOMEM);
+
+	ea->attr.attr.mode = 0444;
+	ea->var = (unsigned long *)hash;
+
+	ret = sysfs_add_file_to_group(&pmu_dev->kobj,
+				      &ea->attr.attr, group_name);
+
+	return ret ? ERR_PTR(ret) : ea;
+}
+
+int etm_perf_add_symlink_sink(struct coresight_device *csdev)
+{
+	const char *name;
+	struct device *dev = &csdev->dev;
+	int err = 0;
+
+	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
+	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
+		return -EINVAL;
+
+	if (csdev->ea != NULL)
+		return -EINVAL;
+
+	name = dev_name(dev);
+	csdev->ea = etm_perf_add_symlink_group(dev, name, "sinks");
+	if (IS_ERR(csdev->ea)) {
+		err = PTR_ERR(csdev->ea);
+		csdev->ea = NULL;
+	} else
+		csdev->ea->attr.show = etm_perf_sink_name_show;
+
+	return err;
+}
+
+static void etm_perf_del_symlink_group(struct dev_ext_attribute *ea, const char *group_name)
+{
+	struct device *pmu_dev = etm_pmu.dev;
+
+	sysfs_remove_file_from_group(&pmu_dev->kobj,
+				     &ea->attr.attr, group_name);
+}
+
+void etm_perf_del_symlink_sink(struct coresight_device *csdev)
+{
+	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
+	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
+		return;
+
+	if (!csdev->ea)
+		return;
+
+	etm_perf_del_symlink_group(csdev->ea, "sinks");
+	csdev->ea = NULL;
+}
+
+static ssize_t etm_perf_cscfg_event_show(struct device *dev,
+					 struct device_attribute *dattr,
+					 char *buf)
+{
+	struct dev_ext_attribute *ea;
+
+	ea = container_of(dattr, struct dev_ext_attribute, attr);
+	return scnprintf(buf, PAGE_SIZE, "configid=0x%lx\n", (unsigned long)(ea->var));
+}
+
+int etm_perf_add_symlink_cscfg(struct device *dev, struct cscfg_config_desc *config_desc)
+{
+	int err = 0;
+
+	if (config_desc->event_ea != NULL)
+		return 0;
+
+	config_desc->event_ea = etm_perf_add_symlink_group(dev, config_desc->name, "events");
+
+	/* set the show function to the custom cscfg event */
+	if (!IS_ERR(config_desc->event_ea))
+		config_desc->event_ea->attr.show = etm_perf_cscfg_event_show;
+	else {
+		err = PTR_ERR(config_desc->event_ea);
+		config_desc->event_ea = NULL;
+	}
+
+	return err;
+}
+
+void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *config_desc)
+{
+	if (!config_desc->event_ea)
+		return;
+
+	etm_perf_del_symlink_group(config_desc->event_ea, "events");
+	config_desc->event_ea = NULL;
+}
+
+int __init etm_perf_init(void)
+{
+	int ret;
+
+	etm_pmu.capabilities		= (PERF_PMU_CAP_EXCLUSIVE |
+					   PERF_PMU_CAP_ITRACE);
+
+	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;
+	etm_pmu.module			= THIS_MODULE;
+
+	ret = perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1);
+	if (ret == 0)
+		etm_perf_up = true;
+
+	return ret;
+}
+
+void etm_perf_exit(void)
+{
+	perf_pmu_unregister(&etm_pmu);
+}