perf probe: Fix to get ummapped symbol address on kernel

Fix to get correctly unmapped symbol address on kernel.  This allows us
to probe on syscall symbols which are aliases of SyS_ functions with
using debuginfo.

Without this fix:
  ----
  # ./perf probe -a sys_write
  Failed to find debug information for address 3b0100
  Probe point 'sys_write' not found.
    Error: Failed to add events.
  ----
The address 0x3b0100 is a mapped address, and not usable
in debuginfo.

With this fix:
  ----
  # ./perf probe -a sys_write
  Added new event:
    probe:sys_write      (on sys_write)

  You can now use it in all perf tools, such as:

          perf record -e probe:sys_write -aR sleep 1
  ----

Signed-off-by: Masami Hiramatsu <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 4 insertions, 1 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 6b95985db5b0..8feac0774c41 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -310,7 +310,10 @@ static int find_alternative_probe_point(struct debuginfo *dinfo,
 
 	/* Find the address of given function */
 	map__for_each_symbol_by_name(map, pp->function, sym) {
-		address = sym->start;
+		if (uprobes)
+			address = sym->start;
+		else
+			address = map->unmap_ip(map, sym->start);
 		break;
 	}
 	if (!address) {