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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2/* const.h: Macros for dealing with constants. */
3
4#ifndef _UAPI_LINUX_CONST_H
5#define _UAPI_LINUX_CONST_H
6
7/* Some constant macros are used in both assembler and
8 * C code. Therefore we cannot annotate them always with
9 * 'UL' and other type specifiers unilaterally. We
10 * use the following macros to deal with this.
11 *
12 * Similarly, _AT() will cast an expression with a type in C, but
13 * leave it unchanged in asm.
14 */
15
16#ifdef __ASSEMBLY__
17#define _AC(X,Y) X
18#define _AT(T,X) X
19#else
20#define __AC(X,Y) (X##Y)
21#define _AC(X,Y) __AC(X,Y)
22#define _AT(T,X) ((T)(X))
23#endif
24
25#define _UL(x) (_AC(x, UL))
26#define _ULL(x) (_AC(x, ULL))
27
28#define _BITUL(x) (_UL(1) << (x))
29#define _BITULL(x) (_ULL(1) << (x))
30
31#if !defined(__ASSEMBLY__)
32/*
33 * Missing asm support
34 *
35 * __BIT128() would not work in the asm code, as it shifts an
36 * 'unsigned __int128' data type as direct representation of
37 * 128 bit constants is not supported in the gcc compiler, as
38 * they get silently truncated.
39 *
40 * TODO: Please revisit this implementation when gcc compiler
41 * starts representing 128 bit constants directly like long
42 * and unsigned long etc. Subsequently drop the comment for
43 * GENMASK_U128() which would then start supporting asm code.
44 */
45#define _BIT128(x) ((unsigned __int128)(1) << (x))
46#endif
47
48#define __ALIGN_KERNEL(x, a) __ALIGN_KERNEL_MASK(x, (__typeof__(x))(a) - 1)
49#define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask))
50
51#define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
52
53#endif /* _UAPI_LINUX_CONST_H */