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