[mirror_ubuntu-bionic-kernel.git] / include / linux / kconfig.h

/* 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.
 */
#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.
 */
#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))

/* Make sure we always have all types and struct attributes defined. */
#include <linux/compiler_types.h>

#endif /* __LINUX_KCONFIG_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
2a11c8ea MM	2	#ifndef __LINUX_KCONFIG_H
	3	#define __LINUX_KCONFIG_H
	4
	5	#include <generated/autoconf.h>
	6
425ebd9c AB	7	#ifdef CONFIG_CPU_BIG_ENDIAN
	8	#define __BIG_ENDIAN 4321
	9	#else
	10	#define __LITTLE_ENDIAN 1234
	11	#endif
	12
5e8754fd MY	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.
4091fb95	18	* The following enable to calculate "and" / "or" with macro expansion only.
5e8754fd MY	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
2a11c8ea	28	/*
69349c2d	29	* Helper macros to use CONFIG_ options in C/CPP expressions. Note that
2a11c8ea MM	30	* these only work with boolean and tristate options.
	31	*/
	32
69349c2d PG	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	*/
4f920843 MY	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)
69349c2d	44
2a11c8ea MM	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	*/
c0a0aba8	50	#define IS_BUILTIN(option) __is_defined(option)
2a11c8ea MM	51
	52	/*
	53	* IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
	54	* otherwise.
	55	*/
c0a0aba8	56	#define IS_MODULE(option) __is_defined(option##_MODULE)
2a11c8ea	57
9b174527 AB	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	*/
5e8754fd MY	64	#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
5e8754fd MY	65	__and(IS_MODULE(option), __is_defined(MODULE)))
9b174527	66
02d699f1 MS	67	/*
	68	* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
	69	* 0 otherwise.
	70	*/
5e8754fd	71	#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
02d699f1	72
73fabf90 KC	73	/* Make sure we always have all types and struct attributes defined. */
	74	#include <linux/compiler_types.h>
	75
2a11c8ea	76	#endif /* __LINUX_KCONFIG_H */