1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_INDIRECT_CALL_WRAPPER_H
3 #define _LINUX_INDIRECT_CALL_WRAPPER_H
4 
5 #ifdef CONFIG_RETPOLINE
6 
7 /*
8  * INDIRECT_CALL_$NR - wrapper for indirect calls with $NR known builtin
9  *  @f: function pointer
10  *  @f$NR: builtin functions names, up to $NR of them
11  *  @__VA_ARGS__: arguments for @f
12  *
13  * Avoid retpoline overhead for known builtin, checking @f vs each of them and
14  * eventually invoking directly the builtin function. The functions are check
15  * in the given order. Fallback to the indirect call.
16  */
17 #define INDIRECT_CALL_1(f, f1, ...)					\
18 	({								\
19 		likely(f == f1) ? f1(__VA_ARGS__) : f(__VA_ARGS__);	\
20 	})
21 #define INDIRECT_CALL_2(f, f2, f1, ...)					\
22 	({								\
23 		likely(f == f2) ? f2(__VA_ARGS__) :			\
24 				  INDIRECT_CALL_1(f, f1, __VA_ARGS__);	\
25 	})
26 
27 #define INDIRECT_CALLABLE_DECLARE(f)	f
28 #define INDIRECT_CALLABLE_SCOPE
29 
30 #else
31 #define INDIRECT_CALL_1(f, f1, ...) f(__VA_ARGS__)
32 #define INDIRECT_CALL_2(f, f2, f1, ...) f(__VA_ARGS__)
33 #define INDIRECT_CALLABLE_DECLARE(f)
34 #define INDIRECT_CALLABLE_SCOPE		static
35 #endif
36 
37 /*
38  * We can use INDIRECT_CALL_$NR for ipv6 related functions only if ipv6 is
39  * builtin, this macro simplify dealing with indirect calls with only ipv4/ipv6
40  * alternatives
41  */
42 #if IS_BUILTIN(CONFIG_IPV6)
43 #define INDIRECT_CALL_INET(f, f2, f1, ...) \
44 	INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
45 #elif IS_ENABLED(CONFIG_INET)
46 #define INDIRECT_CALL_INET(f, f2, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__)
47 #else
48 #define INDIRECT_CALL_INET(f, f2, f1, ...) f(__VA_ARGS__)
49 #endif
50 
51 #endif
52