kconfig.h 2.5 KB

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