selftests/ftrace: Add %return suffix tests

Add kprobe %return suffix testcase and syntax error tests
for %return suffix.

Link: https://lkml.kernel.org/r/159972817653.428528.9180599115849301184.stgit@devnote2

Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc

@@ -97,4 +97,10 @@ check_error 'p:kprobes/testevent _do_fork ^abcd=\"foo"'	# DIFF_ARG_TYPE
 check_error '^p:kprobes/testevent _do_fork abcd=\1'	# SAME_PROBE
 fi
 
+# %return suffix errors
+if grep -q "place (kretprobe): .*%return.*" README; then
+check_error 'p vfs_read^%hoge'		# BAD_ADDR_SUFFIX
+check_error 'p ^vfs_read+10%return'	# BAD_RETPROBE
+fi
+
 exit 0

tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_return_suffix.tc

@@ -0,0 +1,21 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Kretprobe %%return suffix test
+# requires: kprobe_events '<symbol>[+<offset>]%return':README
+
+# Test for kretprobe by "r"
+echo 'r:myprobeaccept vfs_read' > kprobe_events
+RESULT1=`cat kprobe_events`
+
+# Test for kretprobe by "%return"
+echo 'p:myprobeaccept vfs_read%return' > kprobe_events
+RESULT2=`cat kprobe_events`
+
+if [ "$RESULT1" != "$RESULT2" ]; then
+	echo "Error: %return suffix didn't make a return probe."
+	echo "r-command: $RESULT1"
+	echo "%return: $RESULT2"
+	exit_fail
+fi
+
+echo > kprobe_events

tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc

@@ -17,4 +17,10 @@ check_error 'p /bin/sh:10(10)^a'	# BAD_REFCNT_SUFFIX
 check_error 'p /bin/sh:10 ^@+ab'	# BAD_FILE_OFFS
 check_error 'p /bin/sh:10 ^@symbol'	# SYM_ON_UPROBE
 
+# %return suffix error
+if grep -q "place (uprobe): .*%return.*" README; then
+check_error 'p /bin/sh:10^%hoge'	# BAD_ADDR_SUFFIX
+check_error 'p /bin/sh:10(10)^%return'	# BAD_REFCNT_SUFFIX
+fi
+
 exit 0