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