[PATCH v6 8/9] selftests/ftrace: Add BTF fields access testcases

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Add test cases for accessing the data structure fields using BTF info.
This includes the field access from parameters and retval, and accessing
string information.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
Acked-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
Changes in v2:
 - Use '$retval' instead of 'retval'.
 - Add a test that use both '$retval' and '$arg1' for fprobe.
Changes in v3:
 - Change a test case with a numeric value.
 - Add a test case with mixed '.' and '->' operators.
Changes in v5:
 - Check fields access availability.
---
 .../ftrace/test.d/dynevent/add_remove_btfarg.tc    |   20 ++++++++++++++++++++
 .../ftrace/test.d/dynevent/fprobe_syntax_errors.tc |    8 ++++++++
 2 files changed, 28 insertions(+)

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
index f34b14ef9781..b9c21a81d248 100644
--- a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
@@ -5,6 +5,7 @@
 
 KPROBES=
 FPROBES=
+FIELDS=
 
 if grep -qF "p[:[<group>/][<event>]] <place> [<args>]" README ; then
   KPROBES=yes
@@ -12,6 +13,9 @@ fi
 if grep -qF "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README ; then
   FPROBES=yes
 fi
+if grep -qF "<argname>[->field[->field|.field...]]" README ; then
+  FIELDS=yes
+fi
 
 if [ -z "$KPROBES" -a -z "$FPROBES" ] ; then
   exit_unsupported
@@ -21,6 +25,9 @@ echo 0 > events/enable
 echo > dynamic_events
 
 TP=kfree
+TP2=kmem_cache_alloc
+TP3=getname_flags
+TP4=sched_wakeup
 
 if [ "$FPROBES" ] ; then
 echo "f:fpevent $TP object" >> dynamic_events
@@ -33,6 +40,7 @@ echo > dynamic_events
 
 echo "f:fpevent $TP "'$arg1' >> dynamic_events
 grep -q "fpevent.*object=object" dynamic_events
+
 echo > dynamic_events
 
 echo "f:fpevent $TP "'$arg*' >> dynamic_events
@@ -45,6 +53,18 @@ fi
 
 echo > dynamic_events
 
+if [ "$FIELDS" ] ; then
+echo "t:tpevent ${TP2} obj_size=s->object_size" >> dynamic_events
+echo "f:fpevent ${TP3}%return path=\$retval->name:string" >> dynamic_events
+echo "t:tpevent2 ${TP4} p->se.group_node.next->prev" >> dynamic_events
+
+grep -q "tpevent .*obj_size=s->object_size" dynamic_events
+grep -q "fpevent.*path=\$retval->name:string" dynamic_events
+grep -q 'tpevent2 .*p->se.group_node.next->prev' dynamic_events
+
+echo > dynamic_events
+fi
+
 if [ "$KPROBES" ] ; then
 echo "p:kpevent $TP object" >> dynamic_events
 grep -q "kpevent.*object=object" dynamic_events
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
index 72563b2e0812..20e42c030095 100644
--- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
@@ -103,6 +103,14 @@ check_error 'f vfs_read%return ^$arg*'		# NOFENTRY_ARGS
 check_error 'f vfs_read ^hoge'			# NO_BTFARG
 check_error 'f kfree ^$arg10'			# NO_BTFARG (exceed the number of parameters)
 check_error 'f kfree%return ^$retval'		# NO_RETVAL
+
+if grep -qF "<argname>[->field[->field|.field...]]" README ; then
+check_error 'f vfs_read%return $retval->^foo'	# NO_PTR_STRCT
+check_error 'f vfs_read file->^foo'		# NO_BTF_FIELD
+check_error 'f vfs_read file^-.foo'		# BAD_HYPHEN
+check_error 'f vfs_read ^file:string'		# BAD_TYPE4STR
+fi
+
 else
 check_error 'f vfs_read ^$arg*'			# NOSUP_BTFARG
 check_error 't kfree ^$arg*'			# NOSUP_BTFARG