1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 /* const.h: Macros for dealing with constants. */ 3 #pragma once 4 5 #ifndef _UAPI_LINUX_CONST_H 6 #define _UAPI_LINUX_CONST_H 7 8 /* Some constant macros are used in both assembler and 9 * C code. Therefore we cannot annotate them always with 10 * 'UL' and other type specifiers unilaterally. We 11 * use the following macros to deal with this. 12 * 13 * Similarly, _AT() will cast an expression with a type in C, but 14 * leave it unchanged in asm. 15 */ 16 17 #ifdef __ASSEMBLY__ 18 #define _AC(X,Y) X 19 #define _AT(T,X) X 20 #else 21 #define __AC(X,Y) (X##Y) 22 #define _AC(X,Y) __AC(X,Y) 23 #define _AT(T,X) ((T)(X)) 24 #endif 25 26 #define _UL(x) (_AC(x, UL)) 27 #define _ULL(x) (_AC(x, ULL)) 28 29 #define _BITUL(x) (_UL(1) << (x)) 30 #define _BITULL(x) (_ULL(1) << (x)) 31 32 #define __ALIGN_KERNEL(x, a) __ALIGN_KERNEL_MASK(x, (__typeof__(x))(a) - 1) 33 #define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask)) 34 35 #define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) 36 37 /* 38 * This returns a constant expression while determining if an argument is 39 * a constant expression, most importantly without evaluating the argument. 40 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de> 41 */ 42 #define __is_constexpr(x) \ 43 (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) 44 45 #endif /* _UAPI_LINUX_CONST_H */ 46