| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef __LINUX_KCONFIG_H |
| #define __LINUX_KCONFIG_H |
| |
| #include <generated/autoconf.h> |
| |
| #ifdef CONFIG_CPU_BIG_ENDIAN |
| #define __BIG_ENDIAN 4321 |
| #else |
| #define __LITTLE_ENDIAN 1234 |
| #endif |
| |
| #define __ARG_PLACEHOLDER_1 0, |
| #define __take_second_arg(__ignored, val, ...) val |
| |
| /* |
| * The use of "&&" / "||" is limited in certain expressions. |
| * The following enable to calculate "and" / "or" with macro expansion only. |
| */ |
| #define __and(x, y) ___and(x, y) |
| #define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y) |
| #define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0) |
| |
| #define __or(x, y) ___or(x, y) |
| #define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y) |
| #define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y) |
| |
| /* |
| * Helper macros to use CONFIG_ options in C/CPP expressions. Note that |
| * these only work with boolean and tristate options. |
| */ |
| |
| /* |
| * Getting something that works in C and CPP for an arg that may or may |
| * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1" |
| * we match on the placeholder define, insert the "0," for arg1 and generate |
| * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one). |
| * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when |
| * the last step cherry picks the 2nd arg, we get a zero. |
| */ |
| #define __is_defined(x) ___is_defined(x) |
| #define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val) |
| #define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0) |
| |
| /* |
| * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0 |
| * otherwise. For boolean options, this is equivalent to |
| * IS_ENABLED(CONFIG_FOO). |
| */ |
| #define IS_BUILTIN(option) __is_defined(option) |
| |
| /* |
| * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0 |
| * otherwise. CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1" in |
| * autoconf.h. |
| */ |
| #define IS_MODULE(option) __is_defined(option##_MODULE) |
| |
| /* |
| * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled |
| * code can call a function defined in code compiled based on CONFIG_FOO. |
| * This is similar to IS_ENABLED(), but returns false when invoked from |
| * built-in code when CONFIG_FOO is set to 'm'. |
| */ |
| #define IS_REACHABLE(option) __or(IS_BUILTIN(option), \ |
| __and(IS_MODULE(option), __is_defined(MODULE))) |
| |
| /* |
| * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm', |
| * 0 otherwise. Note that CONFIG_FOO=y results in "#define CONFIG_FOO 1" in |
| * autoconf.h, while CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1". |
| */ |
| #define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option)) |
| |
| #endif /* __LINUX_KCONFIG_H */ |