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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: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/20190131184714.20388-4-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Mathieu Poirier 2019-01-31 11:47:10 -07:00 committed by Arnaldo Carvalho de Melo
parent bb8e370bdc
commit 2264439258
3 changed files with 55 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/hwtracing/coresight/coresight-etm-perf.c
View File

@ -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.
*/
sink = coresight_get_enabled_sink(true);
/* 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;

1
drivers/hwtracing/coresight/coresight-priv.h
View File

@ -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);

42
drivers/hwtracing/coresight/coresight.c
View File

@ -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