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1 | /* SPDX-License-Identifier: GPL-2.0 */ | |
2 | #ifndef __LINUX_KCONFIG_H | |
3 | #define __LINUX_KCONFIG_H | |
4 | ||
5 | #include <generated/autoconf.h> | |
6 | ||
7 | #ifdef CONFIG_CPU_BIG_ENDIAN | |
8 | #define __BIG_ENDIAN 4321 | |
9 | #else | |
10 | #define __LITTLE_ENDIAN 1234 | |
11 | #endif | |
12 | ||
13 | #define __ARG_PLACEHOLDER_1 0, | |
14 | #define __take_second_arg(__ignored, val, ...) val | |
15 | ||
16 | /* | |
17 | * The use of "&&" / "||" is limited in certain expressions. | |
18 | * The following enable to calculate "and" / "or" with macro expansion only. | |
19 | */ | |
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) | |
23 | ||
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) | |
27 | ||
28 | /* | |
29 | * Helper macros to use CONFIG_ options in C/CPP expressions. Note that | |
30 | * these only work with boolean and tristate options. | |
31 | */ | |
32 | ||
33 | /* | |
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. | |
40 | */ | |
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) | |
44 | ||
45 | /* | |
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). | |
49 | */ | |
50 | #define IS_BUILTIN(option) __is_defined(option) | |
51 | ||
52 | /* | |
53 | * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0 | |
54 | * otherwise. | |
55 | */ | |
56 | #define IS_MODULE(option) __is_defined(option##_MODULE) | |
57 | ||
58 | /* | |
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'. | |
63 | */ | |
64 | #define IS_REACHABLE(option) __or(IS_BUILTIN(option), \ | |
65 | __and(IS_MODULE(option), __is_defined(MODULE))) | |
66 | ||
67 | /* | |
68 | * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm', | |
69 | * 0 otherwise. | |
70 | */ | |
71 | #define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option)) | |
72 | ||
73 | /* Make sure we always have all types and struct attributes defined. */ | |
74 | #include <linux/compiler_types.h> | |
75 | ||
76 | #endif /* __LINUX_KCONFIG_H */ |