| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | #ifndef __LINUX_KCONFIG_H |
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| 3 | #define __LINUX_KCONFIG_H |
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| 4 | |
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| 5 | #include <generated/autoconf.h> |
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| 6 | |
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| 7 | #ifdef CONFIG_CPU_BIG_ENDIAN |
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| 8 | #define __BIG_ENDIAN 4321 |
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| 9 | #else |
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| 10 | #define __LITTLE_ENDIAN 1234 |
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| 11 | #endif |
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| 12 | |
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| 13 | #define __ARG_PLACEHOLDER_1 0, |
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| 14 | #define __take_second_arg(__ignored, val, ...) val |
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| 15 | |
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| 16 | /* |
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| 17 | * The use of "&&" / "||" is limited in certain expressions. |
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| 18 | * The following enable to calculate "and" / "or" with macro expansion only. |
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| 19 | */ |
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| 20 | #define __and(x, y) ___and(x, y) |
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| 21 | #define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y) |
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| 22 | #define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0) |
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| 23 | |
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| 24 | #define __or(x, y) ___or(x, y) |
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| 25 | #define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y) |
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| 26 | #define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y) |
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| 27 | |
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| 28 | /* |
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| 29 | * Helper macros to use CONFIG_ options in C/CPP expressions. Note that |
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| 30 | * these only work with boolean and tristate options. |
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| 31 | */ |
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| 32 | |
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| 33 | /* |
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| 34 | * Getting something that works in C and CPP for an arg that may or may |
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| 35 | * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1" |
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| 36 | * we match on the placeholder define, insert the "0," for arg1 and generate |
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| 37 | * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one). |
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| 38 | * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when |
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| 39 | * the last step cherry picks the 2nd arg, we get a zero. |
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| 40 | */ |
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| 41 | #define __is_defined(x) ___is_defined(x) |
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| 42 | #define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val) |
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| 43 | #define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0) |
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| 44 | |
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| 45 | /* |
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| 46 | * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0 |
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| 47 | * otherwise. For boolean options, this is equivalent to |
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| 48 | * IS_ENABLED(CONFIG_FOO). |
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| 49 | */ |
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| 50 | #define IS_BUILTIN(option) __is_defined(option) |
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| 51 | |
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| 52 | /* |
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| 53 | * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0 |
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| 54 | * otherwise. CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1" in |
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| 55 | * autoconf.h. |
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| 56 | */ |
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| 57 | #define IS_MODULE(option) __is_defined(option##_MODULE) |
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| 58 | |
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| 59 | /* |
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| 60 | * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled |
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| 61 | * code can call a function defined in code compiled based on CONFIG_FOO. |
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| 62 | * This is similar to IS_ENABLED(), but returns false when invoked from |
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| 63 | * built-in code when CONFIG_FOO is set to 'm'. |
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| 64 | */ |
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| 65 | #define IS_REACHABLE(option) __or(IS_BUILTIN(option), \ |
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| 66 | __and(IS_MODULE(option), __is_defined(MODULE))) |
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| 67 | |
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| 68 | /* |
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| 69 | * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm', |
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| 70 | * 0 otherwise. Note that CONFIG_FOO=y results in "#define CONFIG_FOO 1" in |
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| 71 | * autoconf.h, while CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1". |
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| 72 | */ |
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| 73 | #define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option)) |
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| 74 | |
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| 75 | #endif /* __LINUX_KCONFIG_H */ |
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| 76 | |
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