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1#ifndef __LINUX_KCONFIG_H
2#define __LINUX_KCONFIG_H
3
4#include <generated/autoconf.h>
5
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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
2a11c8ea 21/*
69349c2d 22 * Helper macros to use CONFIG_ options in C/CPP expressions. Note that
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23 * these only work with boolean and tristate options.
24 */
25
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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 */
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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)
69349c2d 37
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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 */
c0a0aba8 43#define IS_BUILTIN(option) __is_defined(option)
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44
45/*
46 * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
47 * otherwise.
48 */
c0a0aba8 49#define IS_MODULE(option) __is_defined(option##_MODULE)
2a11c8ea 50
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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 */
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57#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
58 __and(IS_MODULE(option), __is_defined(MODULE)))
9b174527 59
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60/*
61 * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
62 * 0 otherwise.
63 */
5e8754fd 64#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
02d699f1 65
2a11c8ea 66#endif /* __LINUX_KCONFIG_H */