ftrace: Return ENOTSUPP when DYNAMIC_FTRACE_WITH_DIRECT_CALLS is not configured

4ast · rostedt · commit eb01fedc3d53 · 2019-11-20T18:52:23.000-05:00
When CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS is not set it's best to have the stub functions return ENOTSUPP instead of ENODEV, otherwise ENODEV is a valid error when ip is incorrect which is indistinguishable from ftrace not compiled in. Link: http://lkml.kernel.org/r/CAADnVQ+OzTikM9EhrfsC7NFsVYhATW1SVHxK64w3xn9qpk81pg@mail.gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
@@ -268,16 +268,16 @@ int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
 # define ftrace_direct_func_count 0
 static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
 {
-	return -ENODEV;
+	return -ENOTSUPP;
 }
 static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
 {
-	return -ENODEV;
+	return -ENOTSUPP;
 }
 static inline int modify_ftrace_direct(unsigned long ip,
 				       unsigned long old_addr, unsigned long new_addr)
 {
-	return -ENODEV;
+	return -ENOTSUPP;
 }
 static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
 {

Original file line number	Diff line number	Diff line change
`@@ -268,16 +268,16 @@ int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,`
`268`	`268`	`# define ftrace_direct_func_count 0`
`269`	`269`	`static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)`
`270`	`270`	`{`
`271`		`- return -ENODEV;`
	`271`	`+ return -ENOTSUPP;`
`272`	`272`	`}`
`273`	`273`	`static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr)`
`274`	`274`	`{`
`275`		`- return -ENODEV;`
	`275`	`+ return -ENOTSUPP;`
`276`	`276`	`}`
`277`	`277`	`static inline int modify_ftrace_direct(unsigned long ip,`
`278`	`278`	`unsigned long old_addr, unsigned long new_addr)`
`279`	`279`	`{`
`280`		`- return -ENODEV;`
	`280`	`+ return -ENOTSUPP;`
`281`	`281`	`}`
`282`	`282`	`static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)`
`283`	`283`	`{`