[PATCH v5 6/7] perf/sdt: List events fetched from uprobe_events

[Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>]

List those events which are fetched from uprobe_events as 'event addr@file'
followed by hint on how these events can be deleted with 'perf probe -d'
command.

For example:
  $ sudo cat /sys/kernel/debug/tracing/uprobe_events
    p:sdt_libpthread/mutex_release /usr/lib64/libpthread-2.24.so:0x000000000000b126

  $ sudo ./perf record -a -e sdt_libpthread:mutex_release
    Matching event(s) from uprobe_events:
       sdt_libpthread:mutex_release  0xb126@/usr/lib64/libpthread-2.24.so
    Use 'perf probe -d <event>' to delete event(s).

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
 tools/perf/util/probe-event.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7bf8783..e150de0 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -3593,6 +3593,24 @@ static void sdt_warn_multi_events(int ctr, struct perf_probe_event *pev)
 		   ctr, pev->group, pev->event);
 }
 
+static void print_exst_sdt_events(struct probe_trace_event *tev)
+{
+	static bool msg_head;
+
+	if (!msg_head) {
+		pr_info("Matching event(s) from uprobe_events:\n");
+		msg_head = true;
+	}
+
+	pr_info("   %s:%s  0x%" PRIx64 "@%s\n", tev->group,
+		tev->event, tev->point.address, tev->point.module);
+}
+
+static void print_exst_sdt_event_footer(void)
+{
+	pr_info("Use 'perf probe -d <event>' to delete event(s).\n\n");
+}
+
 static int sdt_event_probepoint_exists(struct perf_probe_event *pev,
 				       struct probe_trace_event *tevs,
 				       int ntevs,
@@ -3607,10 +3625,14 @@ static int sdt_event_probepoint_exists(struct perf_probe_event *pev,
 			if (ret < 0)
 				return ret;
 
+			print_exst_sdt_events(&tevs[i]);
 			ctr++;
 		}
 	}
 
+	if (ctr > 0)
+		print_exst_sdt_event_footer();
+
 	if (ctr > 1)
 		sdt_warn_multi_events(ctr, pev);
 
@@ -3660,11 +3682,16 @@ static int sdt_merge_events(struct perf_probe_event *pev,
 
 				if (!ptrn_used)
 					shift_sdt_events(pev, i);
+
+				print_exst_sdt_events(&exst_tevs[j]);
 				ctr++;
 			}
 		}
 	}
 
+	if (ctr > 0)
+		print_exst_sdt_event_footer();
+
 	if (!ptrn_used || ctr == 0) {
 		/*
 		 * Create probe point for all probe-cached events by
-- 
2.9.3