rtla/trace: Add trace events helpers

Add a set of helper functions to allow the rtla tools to enable
additional tracepoints in the trace instance.

Link: https://lkml.kernel.org/r/932398b36c1bbaa22c7810d7a40ca9b8c5595b94.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c
index 83de259abcc1eff0d6a3169ba55e056d411106bb..9ad3d8890ec5cb852fd5170146b95193d135f1bf 100644 (file)
--- a/tools/tracing/rtla/src/trace.c
+++ b/tools/tracing/rtla/src/trace.c
@@ -190,3 +190,107 @@ int trace_instance_start(struct trace_instance *trace)
 {
        return tracefs_trace_on(trace->inst);
 }
+
+/*
+ * trace_events_free - free a list of trace events
+ */
+static void trace_events_free(struct trace_events *events)
+{
+       struct trace_events *tevent = events;
+       struct trace_events *free_event;
+
+       while (tevent) {
+               free_event = tevent;
+
+               tevent = tevent->next;
+
+               free(free_event->system);
+               free(free_event);
+       }
+}
+
+/*
+ * trace_event_alloc - alloc and parse a single trace event
+ */
+struct trace_events *trace_event_alloc(const char *event_string)
+{
+       struct trace_events *tevent;
+
+       tevent = calloc(1, sizeof(*tevent));
+       if (!tevent)
+               return NULL;
+
+       tevent->system = strdup(event_string);
+       if (!tevent->system) {
+               free(tevent);
+               return NULL;
+       }
+
+       tevent->event = strstr(tevent->system, ":");
+       if (tevent->event) {
+               *tevent->event = '\0';
+               tevent->event = &tevent->event[1];
+       }
+
+       return tevent;
+}
+
+/*
+ * trace_events_disable - disable all trace events
+ */
+void trace_events_disable(struct trace_instance *instance,
+                         struct trace_events *events)
+{
+       struct trace_events *tevent = events;
+
+       if (!events)
+               return;
+
+       while (tevent) {
+               debug_msg("Disabling event %s:%s\n", tevent->system, tevent->event ? : "*");
+               if (tevent->enabled)
+                       tracefs_event_disable(instance->inst, tevent->system, tevent->event);
+
+               tevent->enabled = 0;
+               tevent = tevent->next;
+       }
+}
+
+/*
+ * trace_events_enable - enable all events
+ */
+int trace_events_enable(struct trace_instance *instance,
+                       struct trace_events *events)
+{
+       struct trace_events *tevent = events;
+       int retval;
+
+       while (tevent) {
+               debug_msg("Enabling event %s:%s\n", tevent->system, tevent->event ? : "*");
+               retval = tracefs_event_enable(instance->inst, tevent->system, tevent->event);
+               if (retval < 0) {
+                       err_msg("Error enabling event %s:%s\n", tevent->system,
+                               tevent->event ? : "*");
+                       return 1;
+               }
+
+
+               tevent->enabled = 1;
+               tevent = tevent->next;
+       }
+
+       return 0;
+}
+
+/*
+ * trace_events_destroy - disable and free all trace events
+ */
+void trace_events_destroy(struct trace_instance *instance,
+                         struct trace_events *events)
+{
+       if (!events)
+               return;
+
+       trace_events_disable(instance, events);
+       trace_events_free(events);
+}

diff --git a/tools/tracing/rtla/src/trace.h b/tools/tracing/rtla/src/trace.h
index 0ea1df0ad9a77cff3830964825a0cc9b5649110f..9f9751f7ee36f4920ea3073559b0a137edf37d3d 100644 (file)
--- a/tools/tracing/rtla/src/trace.h
+++ b/tools/tracing/rtla/src/trace.h
@@ -2,6 +2,13 @@
 #include <tracefs.h>
 #include <stddef.h>
 
+struct trace_events {
+       struct trace_events *next;
+       char *system;
+       char *event;
+       char enabled;
+};
+
 struct trace_instance {
        struct tracefs_instance         *inst;
        struct tep_handle               *tep;
@@ -25,3 +32,11 @@ void destroy_instance(struct tracefs_instance *inst);
 int save_trace_to_file(struct tracefs_instance *inst, const char *filename);
 int collect_registered_events(struct tep_event *tep, struct tep_record *record,
                              int cpu, void *context);
+
+struct trace_events *trace_event_alloc(const char *event_string);
+void trace_events_disable(struct trace_instance *instance,
+                         struct trace_events *events);
+void trace_events_destroy(struct trace_instance *instance,
+                         struct trace_events *events);
+int trace_events_enable(struct trace_instance *instance,
+                         struct trace_events *events);