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 $NR of them 11 * @__VA_ARGS__: arguments for @f 12 * 13 * Avoid retpoline overhead for known builtin, checking @f vs each of them and 14 * eventually invoking directly the builtin function. The functions are checked 15 * in the given order. Fallback to the indirect call. 16 */ 17 #define INDIRECT_CALL_1(f, f1, ...) \ 18 ({ \ 19 typeof(f) __f1 = (f); \ 20 likely(__f1 == f1) ? f1(__VA_ARGS__) : __f1(__VA_ARGS__); \ 21 }) 22 #define INDIRECT_CALL_2(f, f2, f1, ...) \ 23 ({ \ 24 typeof(f) __f2 = (f); \ 25 likely(__f2 == f2) ? f2(__VA_ARGS__) : \ 26 INDIRECT_CALL_1(__f2, f1, __VA_ARGS__); \ 27 }) 28 #define INDIRECT_CALL_3(f, f3, f2, f1, ...) \ 29 ({ \ 30 typeof(f) __f3 = (f); \ 31 likely(__f3 == f3) ? f3(__VA_ARGS__) : \ 32 INDIRECT_CALL_2(__f3, f2, f1, __VA_ARGS__); \ 33 }) 34 #define INDIRECT_CALL_4(f, f4, f3, f2, f1, ...) \ 35 ({ \ 36 typeof(f) __f4 = (f); \ 37 likely(__f4 == f4) ? f4(__VA_ARGS__) : \ 38 INDIRECT_CALL_3(__f4, f3, f2, f1, __VA_ARGS__); \ 39 }) 40 41 #define INDIRECT_CALLABLE_DECLARE(f) f 42 #define INDIRECT_CALLABLE_SCOPE 43 #define EXPORT_INDIRECT_CALLABLE(f) EXPORT_SYMBOL(f) 44 45 #else 46 #define INDIRECT_CALL_1(f, f1, ...) f(__VA_ARGS__) 47 #define INDIRECT_CALL_2(f, f2, f1, ...) f(__VA_ARGS__) 48 #define INDIRECT_CALL_3(f, f3, f2, f1, ...) f(__VA_ARGS__) 49 #define INDIRECT_CALL_4(f, f4, f3, f2, f1, ...) f(__VA_ARGS__) 50 #define INDIRECT_CALLABLE_DECLARE(f) 51 #define INDIRECT_CALLABLE_SCOPE static 52 #define EXPORT_INDIRECT_CALLABLE(f) 53 #endif 54 55 /* 56 * We can use INDIRECT_CALL_$NR for ipv6 related functions only if ipv6 is 57 * builtin, this macro simplify dealing with indirect calls with only ipv4/ipv6 58 * alternatives 59 */ 60 #if IS_BUILTIN(CONFIG_IPV6) 61 #define INDIRECT_CALL_INET(f, f2, f1, ...) \ 62 INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__) 63 #elif IS_ENABLED(CONFIG_INET) 64 #define INDIRECT_CALL_INET(f, f2, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__) 65 #else 66 #define INDIRECT_CALL_INET(f, f2, f1, ...) f(__VA_ARGS__) 67 #endif 68 69 #if IS_ENABLED(CONFIG_INET) 70 #define INDIRECT_CALL_INET_1(f, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__) 71 #else 72 #define INDIRECT_CALL_INET_1(f, f1, ...) f(__VA_ARGS__) 73 #endif 74 75 #endif 76