1 #ifndef __LINUX_KCONFIG_H 2 #define __LINUX_KCONFIG_H 3 4 #include <generated/autoconf.h> 5 6 #define __ARG_PLACEHOLDER_1 0, 7 #define __take_second_arg(__ignored, val, ...) val 8 9 /* 10 * The use of "&&" / "||" is limited in certain expressions. 11 * The followings enable to calculate "and" / "or" with macro expansion only. 12 */ 13 #define __and(x, y) ___and(x, y) 14 #define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y) 15 #define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0) 16 17 #define __or(x, y) ___or(x, y) 18 #define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y) 19 #define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y) 20 21 /* 22 * Helper macros to use CONFIG_ options in C/CPP expressions. Note that 23 * these only work with boolean and tristate options. 24 */ 25 26 /* 27 * Getting something that works in C and CPP for an arg that may or may 28 * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1" 29 * we match on the placeholder define, insert the "0," for arg1 and generate 30 * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one). 31 * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when 32 * the last step cherry picks the 2nd arg, we get a zero. 33 */ 34 #define __is_defined(x) ___is_defined(x) 35 #define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val) 36 #define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0) 37 38 /* 39 * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0 40 * otherwise. For boolean options, this is equivalent to 41 * IS_ENABLED(CONFIG_FOO). 42 */ 43 #define IS_BUILTIN(option) __is_defined(option) 44 45 /* 46 * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0 47 * otherwise. 48 */ 49 #define IS_MODULE(option) __is_defined(option##_MODULE) 50 51 /* 52 * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled 53 * code can call a function defined in code compiled based on CONFIG_FOO. 54 * This is similar to IS_ENABLED(), but returns false when invoked from 55 * built-in code when CONFIG_FOO is set to 'm'. 56 */ 57 #define IS_REACHABLE(option) __or(IS_BUILTIN(option), \ 58 __and(IS_MODULE(option), __is_defined(MODULE))) 59 60 /* 61 * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm', 62 * 0 otherwise. 63 */ 64 #define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option)) 65 66 #endif /* __LINUX_KCONFIG_H */ 67