perf symbols: Provide libtraceevent callback to resolve kernel symbols

That provides the function signature expected by libtraceevent's
pevent_set_function_resolver().
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-ie6hvlb6u15y4ulg9j1612zg@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/machine.c

@@ -1993,3 +1993,17 @@ struct dso *machine__findnew_dso(struct machine *machine, const char *filename)
 {
 	return dsos__findnew(&machine->dsos, filename);
 }
+
+char *machine__resolve_kernel_addr(void *vmachine, unsigned long long *addrp, char **modp)
+{
+	struct machine *machine = vmachine;
+	struct map *map;
+	struct symbol *sym = map_groups__find_symbol(&machine->kmaps, MAP__FUNCTION, *addrp, &map,  NULL);
+
+	if (sym == NULL)
+		return NULL;
+
+	*modp = __map__is_kmodule(map) ? (char *)map->dso->short_name : NULL;
+	*addrp = map->unmap_ip(map, sym->start);
+	return sym->name;
+}

tools/perf/util/machine.h

@@ -237,5 +237,9 @@ int machine__synthesize_threads(struct machine *machine, struct target *target,
 pid_t machine__get_current_tid(struct machine *machine, int cpu);
 int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
 			     pid_t tid);
+/*
+ * For use with libtraceevent's pevent_set_function_resolver()
+ */
+char *machine__resolve_kernel_addr(void *vmachine, unsigned long long *addrp, char **modp);
 
 #endif /* __PERF_MACHINE_H */

tools/perf/util/trace-event.c

@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <traceevent/event-parse.h>
 #include "trace-event.h"
+#include "machine.h"
 #include "util.h"
 
 /*
@@ -19,6 +20,7 @@
  * there.
  */
 static struct trace_event tevent;
+static bool tevent_initialized;
 
 int trace_event__init(struct trace_event *t)
 {
@@ -32,6 +34,32 @@ int trace_event__init(struct trace_event *t)
 	return pevent ? 0 : -1;
 }
 
+static int trace_event__init2(void)
+{
+	int be = traceevent_host_bigendian();
+	struct pevent *pevent;
+
+	if (trace_event__init(&tevent))
+		return -1;
+
+	pevent = tevent.pevent;
+	pevent_set_flag(pevent, PEVENT_NSEC_OUTPUT);
+	pevent_set_file_bigendian(pevent, be);
+	pevent_set_host_bigendian(pevent, be);
+	tevent_initialized = true;
+	return 0;
+}
+
+int trace_event__register_resolver(struct machine *machine)
+{
+	if (!tevent_initialized && trace_event__init2())
+		return -1;
+
+	return pevent_set_function_resolver(tevent.pevent,
+					    machine__resolve_kernel_addr,
+					    machine);
+}
+
 void trace_event__cleanup(struct trace_event *t)
 {
 	traceevent_unload_plugins(t->plugin_list, t->pevent);
@@ -62,21 +90,8 @@ tp_format(const char *sys, const char *name)
 struct event_format*
 trace_event__tp_format(const char *sys, const char *name)
 {
-	static bool initialized;
-
-	if (!initialized) {
-		int be = traceevent_host_bigendian();
-		struct pevent *pevent;
-
-		if (trace_event__init(&tevent))
-			return NULL;
-
-		pevent = tevent.pevent;
-		pevent_set_flag(pevent, PEVENT_NSEC_OUTPUT);
-		pevent_set_file_bigendian(pevent, be);
-		pevent_set_host_bigendian(pevent, be);
-		initialized = true;
-	}
+	if (!tevent_initialized && trace_event__init2())
+		return NULL;
 
 	return tp_format(sys, name);
 }

tools/perf/util/trace-event.h

@@ -18,6 +18,7 @@ struct trace_event {
 
 int trace_event__init(struct trace_event *t);
 void trace_event__cleanup(struct trace_event *t);
+int trace_event__register_resolver(struct machine *machine);
 struct event_format*
 trace_event__tp_format(const char *sys, const char *name);