@@ -22,6 +22,7 @@
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/init.h>
+#include <linux/parser.h>
#include <linux/perf_event.h>
#include <linux/slab.h>
#include <linux/types.h>
@@ -71,11 +72,25 @@ static const struct attribute_group *etm_pmu_attr_groups[] = {
static void etm_event_read(struct perf_event *event) {}
+static void etm_event_destroy(struct perf_event *event)
+{
+ void *sink;
+
+ sink = perf_event_drv_configs_set(event, NULL);
+ kfree(sink);
+}
+
static int etm_event_init(struct perf_event *event)
{
+ struct hw_perf_event *hw_event = &event->hw;
+
if (event->attr.type != etm_pmu.type)
return -ENOENT;
+ event->destroy = etm_event_destroy;
+ raw_spin_lock_init(&hw_event->drv_configs_lock);
+ hw_event->drv_configs = NULL;
+
return 0;
}
@@ -159,6 +174,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
int nr_pages, bool overwrite)
{
int cpu;
+ char *cmdl_sink;
cpumask_t *mask;
struct coresight_device *sink;
struct etm_event_data *event_data = NULL;
@@ -171,6 +187,14 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
mask = &event_data->mask;
+ /*
+ * If a sink was specified from the perf cmdline it will be part of
+ * the event's drv_configs.
+ */
+ cmdl_sink = (char *)perf_event_drv_configs_get(event);
+ if (IS_ERR(cmdl_sink))
+ cmdl_sink = NULL;
+
/* Setup the path for each CPU in a trace session */
for_each_cpu(cpu, mask) {
struct coresight_device *csdev;
@@ -184,7 +208,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
* list of devices from source to sink that can be
* referenced later when the path is actually needed.
*/
- event_data->path[cpu] = coresight_build_path(csdev, NULL);
+ event_data->path[cpu] = coresight_build_path(csdev, cmdl_sink);
if (!event_data->path[cpu])
goto err;
}
@@ -342,6 +366,118 @@ static void etm_event_del(struct perf_event *event, int mode)
etm_event_stop(event, PERF_EF_UPDATE);
}
+enum {
+ ETM_TOKEN_SINK_CPU,
+ ETM_TOKEN_SINK,
+ ETM_TOKEN_ERR,
+};
+
+static const match_table_t drv_cfg_tokens = {
+ {ETM_TOKEN_SINK_CPU, "sink=cpu%d:%s"},
+ {ETM_TOKEN_SINK, "sink=%s"},
+ {ETM_TOKEN_ERR, NULL},
+};
+
+/**
+ * etm_parse_drv_configs - parse configuration string
+ *
+ * Returns: ERR_PTR() upon error, NULL if the config string CPU is different
+ * from the event's CPU and the address of a valid string if one has
+ * been found.
+ */
+static char *etm_parse_drv_configs(int event_cpu, char *config_str)
+{
+ char *sink = NULL, *config = config_str;
+ int cpu, token;
+ substring_t args[MAX_OPT_ARGS];
+
+ /* See above declared @drv_cfg_tokens for the usable formats */
+ token = match_token(config, drv_cfg_tokens, args);
+ switch (token) {
+ case ETM_TOKEN_SINK:
+ /* Simply return the sink that was specified */
+ sink = match_strdup(&args[0]);
+ break;
+ case ETM_TOKEN_SINK_CPU:
+ /*
+ * We have a sink and a CPU, so we need to make sure the
+ * given CPU matches the event's CPU. If not this sink is
+ * destined to another tracer. This isn't an error hence not
+ * setting @ret.
+ */
+
+ /* Get the cpu */
+ if (match_int(&args[0], &cpu)) {
+ sink = ERR_PTR(-EINVAL);
+ goto out;
+ }
+
+ /* This sink configuration is meant for another CPU */
+ if (event_cpu != cpu)
+ goto out;
+
+ sink = match_strdup(&args[1]);
+ break;
+ default:
+ sink = ERR_PTR(-EINVAL);
+ }
+
+out:
+ return sink;
+}
+
+static int
+etm_set_drv_configs(struct perf_event *event,
+ struct list_head *drv_configs)
+{
+ char *config, *sink;
+ int len;
+ struct perf_drv_config *drv_config;
+ void *old_sink;
+
+ list_for_each_entry(drv_config, drv_configs, entry) {
+ /* ETM HW configuration needs a sink specification */
+ if (!drv_config->option)
+ return -EINVAL;
+
+ len = strlen(drv_config->config) + strlen("=") +
+ strlen(drv_config->option) + 1;
+
+ config = kmalloc(len, GFP_KERNEL);
+ if (!config)
+ return -ENOMEM;
+
+ /* Reconstruct user configuration */
+ snprintf(config, len, "%s=%s",
+ drv_config->config, drv_config->option);
+
+ sink = etm_parse_drv_configs(event->cpu, config);
+ kfree(config);
+
+ /* No need to continue if the parse encountered and error */
+ if (IS_ERR(sink))
+ return PTR_ERR(sink);
+
+ /* A valid sink was found */
+ if (sink)
+ goto found;
+ }
+
+ /*
+ * A sink wasn't found, which isn't automatically an error. Other
+ * options on the cmd line may still need to be parsed.
+ */
+ return 0;
+
+found:
+ /* Record the sink that was found */
+ old_sink = perf_event_drv_configs_set(event, sink);
+ /* And get rid of whatever we had before */
+ kfree(old_sink);
+
+ return 0;
+}
+
int etm_perf_symlink(struct coresight_device *csdev, bool link)
{
char entry[sizeof("cpu9999999")];
@@ -383,6 +519,7 @@ static int __init etm_perf_init(void)
etm_pmu.stop = etm_event_stop;
etm_pmu.add = etm_event_add;
etm_pmu.del = etm_event_del;
+ etm_pmu.set_drv_configs = etm_set_drv_configs;
ret = perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1);
if (ret == 0)
Now that PMU specific configuration is available as part of the event, lookup the sink identified by users from the perf command line and build a path from source to sink. With this functionality it is no longer required to select a sink in a separate step (from sysFS) before a perf trace session can be started. Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> --- drivers/hwtracing/coresight/coresight-etm-perf.c | 139 ++++++++++++++++++++++- 1 file changed, 138 insertions(+), 1 deletion(-) -- 2.7.4