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Commit b5390f4b authored by Mathieu Poirier's avatar Mathieu Poirier Committed by Greg Kroah-Hartman
Browse files

coresight: Use event attributes for sink selection 



This patch uses the information conveyed by perf_event::attr::config2
to select a sink to use for the session.  That way a sink can easily be
selected to be used by more than one source, something that isn't currently
possible with the sysfs implementation.

Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 988036f9

drivers/hwtracing/coresight/coresight-etm-perf.c

+12 −12
Original line number Diff line number Diff line
@@ -31,11 +31,14 @@ static DEFINE_PER_CPU(struct coresight_device *, csdev_src); 
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));

/* Sink ID - same for all ETMs */

PMU_FORMAT_ATTR(sinkid,		"config2:0-31");



static struct attribute *etm_config_formats_attr[] = {

	&format_attr_cycacc.attr,

	&format_attr_timestamp.attr,

	&format_attr_retstack.attr,

	&format_attr_sinkid.attr,

	NULL,

};
@@ -191,6 +194,7 @@ static void etm_free_aux(void *data) 
static void *etm_setup_aux(struct perf_event *event, void **pages,

			   int nr_pages, bool overwrite)

{

	u32 id;

	int cpu = event->cpu;

	cpumask_t *mask;

	struct coresight_device *sink;
@@ -201,18 +205,14 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, 
		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.

	 */

	/* First get the selected sink from user space. */

	if (event->attr.config2) {

		id = (u32)event->attr.config2;

		sink = coresight_get_sink_by_id(id);

	} else {

		sink = coresight_get_enabled_sink(true);

	}



	if (!sink || !sink_ops(sink)->alloc_buffer)

		goto err;

drivers/hwtracing/coresight/coresight-priv.h

+1 −0
Original line number Diff line number Diff line
@@ -147,6 +147,7 @@ void coresight_disable_path(struct list_head *path); 
int coresight_enable_path(struct list_head *path, u32 mode, void *sink_data);

struct coresight_device *coresight_get_sink(struct list_head *path);

struct coresight_device *coresight_get_enabled_sink(bool reset);

struct coresight_device *coresight_get_sink_by_id(u32 id);

struct list_head *coresight_build_path(struct coresight_device *csdev,

				       struct coresight_device *sink);

void coresight_release_path(struct list_head *path);

drivers/hwtracing/coresight/coresight.c

+42 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/err.h>

#include <linux/export.h>

#include <linux/slab.h>

#include <linux/stringhash.h>

#include <linux/mutex.h>

#include <linux/clk.h>

#include <linux/coresight.h>
@@ -541,6 +542,47 @@ struct coresight_device *coresight_get_enabled_sink(bool deactivate) 
	return dev ? to_coresight_device(dev) : NULL;

}



static int coresight_sink_by_id(struct device *dev, void *data)

{

	struct coresight_device *csdev = to_coresight_device(dev);

	unsigned long hash;



	if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||

	     csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {



		if (!csdev->ea)

			return 0;

		/*

		 * See function etm_perf_add_symlink_sink() to know where

		 * this comes from.

		 */

		hash = (unsigned long)csdev->ea->var;



		if ((u32)hash == *(u32 *)data)

			return 1;

	}



	return 0;

}



/**

 * coresight_get_sink_by_id - returns the sink that matches the id

 * @id: Id of the sink to match

 *

 * The name of a sink is unique, whether it is found on the AMBA bus or

 * otherwise.  As such the hash of that name can easily be used to identify

 * a sink.

 */

struct coresight_device *coresight_get_sink_by_id(u32 id)

{

	struct device *dev = NULL;



	dev = bus_find_device(&coresight_bustype, NULL, &id,

			      coresight_sink_by_id);



	return dev ? to_coresight_device(dev) : NULL;

}



/*

 * coresight_grab_device - Power up this device and any of the helper

 * devices connected to it for trace operation. Since the helper devices