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_MITIGATION_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 $NR of them
11 * @__VA_ARGS__: arguments for @f
12 *
13 * Avoid retpoline overhead for known builtin, checking @f vs each of them and
14 * eventually invoking directly the builtin function. The functions are checked
15 * in the given order. Fallback to the indirect call.
16 */
17 #define INDIRECT_CALL_1(f, f1, ...) \
18 ({ \
19 likely(f == f1) ? f1(__VA_ARGS__) : f(__VA_ARGS__); \
20 })
21 #define INDIRECT_CALL_2(f, f2, f1, ...) \
22 ({ \
23 likely(f == f2) ? f2(__VA_ARGS__) : \
24 INDIRECT_CALL_1(f, f1, __VA_ARGS__); \
25 })
26 #define INDIRECT_CALL_3(f, f3, f2, f1, ...) \
27 ({ \
28 likely(f == f3) ? f3(__VA_ARGS__) : \
29 INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__); \
30 })
31 #define INDIRECT_CALL_4(f, f4, f3, f2, f1, ...) \
32 ({ \
33 likely(f == f4) ? f4(__VA_ARGS__) : \
34 INDIRECT_CALL_3(f, f3, f2, f1, __VA_ARGS__); \
35 })
36
37 #define INDIRECT_CALLABLE_DECLARE(f) f
38 #define INDIRECT_CALLABLE_SCOPE
39 #define EXPORT_INDIRECT_CALLABLE(f) EXPORT_SYMBOL(f)
40
41 #else
42 #define INDIRECT_CALL_1(f, f1, ...) f(__VA_ARGS__)
43 #define INDIRECT_CALL_2(f, f2, f1, ...) f(__VA_ARGS__)
44 #define INDIRECT_CALL_3(f, f3, f2, f1, ...) f(__VA_ARGS__)
45 #define INDIRECT_CALL_4(f, f4, f3, f2, f1, ...) f(__VA_ARGS__)
46 #define INDIRECT_CALLABLE_DECLARE(f)
47 #define INDIRECT_CALLABLE_SCOPE static
48 #define EXPORT_INDIRECT_CALLABLE(f)
49 #endif
50
51 /*
52 * We can use INDIRECT_CALL_$NR for ipv6 related functions only if ipv6 is
53 * builtin, this macro simplify dealing with indirect calls with only ipv4/ipv6
54 * alternatives
55 */
56 #if IS_BUILTIN(CONFIG_IPV6)
57 #define INDIRECT_CALL_INET(f, f2, f1, ...) \
58 INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
59 #elif IS_ENABLED(CONFIG_INET)
60 #define INDIRECT_CALL_INET(f, f2, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__)
61 #else
62 #define INDIRECT_CALL_INET(f, f2, f1, ...) f(__VA_ARGS__)
63 #endif
64
65 #if IS_ENABLED(CONFIG_INET)
66 #define INDIRECT_CALL_INET_1(f, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__)
67 #else
68 #define INDIRECT_CALL_INET_1(f, f1, ...) f(__VA_ARGS__)
69 #endif
70
71 #endif
72
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.