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 <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/machine.c

···
 {
 	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

···
 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

···
 #include <linux/kernel.h>
 #include <traceevent/event-parse.h>
 #include "trace-event.h"
+#include "machine.h"
 #include "util.h"
 
 /*
···
  * there.
  */
 static struct trace_event tevent;
+static bool tevent_initialized;
 
 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)
···
 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

···
 
 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);