perf diff: Add kallsyms option

Required for off-box analysis to convert kernel addresses.
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1427212317-7018-1-git-send-email-dsahern@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-diff.txt

@@ -31,6 +31,9 @@ OPTIONS
 --dump-raw-trace::
         Dump raw trace in ASCII.
 
+--kallsyms=<file>::
+        kallsyms pathname
+
 -m::
 --modules::
         Load module symbols. WARNING: use only with -k and LIVE kernel

tools/perf/builtin-diff.c

@@ -791,6 +791,8 @@ static const struct option options[] = {
 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
 		    "dump raw trace in ASCII"),
 	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
+	OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
+		   "file", "kallsyms pathname"),
 	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
 		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
 	OPT_STRING('d', "dsos", &symbol_conf.dso_list_str, "dso[,dso...]",