perf kallsyms: Introduce tool to look for extended symbol information on the running kernel

Its similar to doing grep on a /proc/kallsyms, but it also shows extra
information like the path to the kernel module and the unrelocated
addresses in it, to help in diagnosing problems.

It is also helps demonstrate the use of the symbols routines so that
tool writers can use them more effectively.

Using it:

  $ perf kallsyms e1000_xmit_frame netif_rx usb_stor_set_xfer_buf
  e1000_xmit_frame: [e1000e] /lib/modules/4.9.0+/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko 0xffffffffc046fc10-0xffffffffc0470bb0 (0x19c80-0x1ac20)
  netif_rx: [kernel] [kernel.kallsyms] 0xffffffff916f03a0-0xffffffff916f0410 (0xffffffff916f03a0-0xffffffff916f0410)
  usb_stor_set_xfer_buf: [usb_storage] /lib/modules/4.9.0+/kernel/drivers/usb/storage/usb-storage.ko 0xffffffffc057aea0-0xffffffffc057af19 (0xf10-0xf89)
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-79bk9pakujn4l4vq0f90klv3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-help.c b/tools/perf/builtin-help.c
index 3bdb2c7..93da24a 100644
--- a/tools/perf/builtin-help.c
+++ b/tools/perf/builtin-help.c
@@ -434,7 +434,7 @@ int cmd_help(int argc, const char **argv, const char *prefix __maybe_unused)
 	const char * const builtin_help_subcommands[] = {
 		"buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
 		"record", "report", "bench", "stat", "timechart", "top", "annotate",
-		"script", "sched", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
+		"script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
 #ifdef HAVE_LIBELF_SUPPORT
 		"probe",
 #endif