linux/include/uapi/linux/const.h

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/* const.h: Macros for dealing with constants.  */

#ifndef _UAPI_LINUX_CONST_H
#define _UAPI_LINUX_CONST_H

/* Some constant macros are used in both assembler and
 * C code.  Therefore we cannot annotate them always with
 * 'UL' and other type specifiers unilaterally.  We
 * use the following macros to deal with this.
 *
 * Similarly, _AT() will cast an expression with a type in C, but
 * leave it unchanged in asm.
 */

#ifdef __ASSEMBLY__
#define _AC(X,Y) …
#define _AT(T,X) …
#else
#define __AC …
#define _AC …
#define _AT …
#endif

#define _UL(x) …
#define _ULL(x) …

#define _BITUL(x) …
#define _BITULL(x) …

#if !defined(__ASSEMBLY__)
/*
 * Missing asm support
 *
 * __BIT128() would not work in the asm code, as it shifts an
 * 'unsigned __init128' data type as direct representation of
 * 128 bit constants is not supported in the gcc compiler, as
 * they get silently truncated.
 *
 * TODO: Please revisit this implementation when gcc compiler
 * starts representing 128 bit constants directly like long
 * and unsigned long etc. Subsequently drop the comment for
 * GENMASK_U128() which would then start supporting asm code.
 */
#define _BIT128 …
#endif

#define __ALIGN_KERNEL(x, a) …
#define __ALIGN_KERNEL_MASK(x, mask) …

#define __KERNEL_DIV_ROUND_UP(n, d) …

#endif /* _UAPI_LINUX_CONST_H */