perf probe: Allow to add events on the local functions

Allow to add events on the local functions without debuginfo.
(With the debuginfo, we can add events even on inlined functions)
Currently, probing on local functions requires debuginfo to
locate actual address. It is also possible without debuginfo since
we have symbol maps.

Without this change;
  ----
  # ./perf probe -a t_show
  Added new event:
    probe:t_show         (on t_show)

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

          perf record -e probe:t_show -aR sleep 1

  # ./perf probe -x perf -a identity__map_ip
  no symbols found in /kbuild/ksrc/linux-3/tools/perf/perf, maybe install a debug package?
  Failed to load map.
    Error: Failed to add events. (-22)
  ----
As the above results, perf probe just put one event
on the first found symbol for kprobe event. Moreover,
for uprobe event, perf probe failed to find local
functions.

With this change;
  ----
  # ./perf probe -a t_show
  Added new events:
    probe:t_show         (on t_show)
    probe:t_show_1       (on t_show)
    probe:t_show_2       (on t_show)
    probe:t_show_3       (on t_show)

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

          perf record -e probe:t_show_3 -aR sleep 1

  # ./perf probe -x perf -a identity__map_ip
  Added new events:
    probe_perf:identity__map_ip (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf)
    probe_perf:identity__map_ip_1 (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf)
    probe_perf:identity__map_ip_2 (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf)
    probe_perf:identity__map_ip_3 (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf)

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

          perf record -e probe_perf:identity__map_ip_3 -aR sleep 1
  ----
Now we succeed to put events on every given local functions
for both kprobes and uprobes. :)

Note that this also introduces some symbol rbtree
iteration macros; symbols__for_each, dso__for_each_symbol,
and map__for_each_symbol. These are for walking through
the symbol list in a map.

Changes from v2:
  - Fix add_exec_to_probe_trace_events() not to convert address
    to tp->symbol any more.
  - Fix to set kernel probes based on ref_reloc_sym.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: "David A. Long" <dave.long@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20140206053225.29635.15026.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index cd7d6f078cdd..ab06f1c03655 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -102,6 +102,16 @@ struct dso {
 	char		 name[0];
 };
 
+/* dso__for_each_symbol - iterate over the symbols of given type
+ *
+ * @dso: the 'struct dso *' in which symbols itereated
+ * @pos: the 'struct symbol *' to use as a loop cursor
+ * @n: the 'struct rb_node *' to use as a temporary storage
+ * @type: the 'enum map_type' type of symbols
+ */
+#define dso__for_each_symbol(dso, pos, n, type)	\
+	symbols__for_each_entry(&(dso)->symbols[(type)], pos, n)
+
 static inline void dso__set_loaded(struct dso *dso, enum map_type type)
 {
 	dso->loaded |= (1 << type);