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