[thirdparty/linux.git] / tools / include / linux / bits.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_BITS_H
#define __LINUX_BITS_H

#include <linux/const.h>
#include <vdso/bits.h>
#include <uapi/linux/bits.h>
#include <asm/bitsperlong.h>

#define BIT_MASK(nr)		(UL(1) << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
#define BIT_ULL_MASK(nr)	(ULL(1) << ((nr) % BITS_PER_LONG_LONG))
#define BIT_ULL_WORD(nr)	((nr) / BITS_PER_LONG_LONG)
#define BITS_PER_BYTE		8
#define BITS_PER_TYPE(type)	(sizeof(type) * BITS_PER_BYTE)

/*
 * Create a contiguous bitmask starting at bit position @l and ending at
 * position @h. For example
 * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
 */
#if !defined(__ASSEMBLY__)

/*
 * Missing asm support
 *
 * GENMASK_U*() and BIT_U*() depend on BITS_PER_TYPE() which relies on sizeof(),
 * something not available in asm. Nevertheless, fixed width integers is a C
 * concept. Assembly code can rely on the long and long long versions instead.
 */

#include <linux/build_bug.h>
#include <linux/compiler.h>
#include <linux/overflow.h>

#define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h)))

/*
 * Generate a mask for the specified type @t. Additional checks are made to
 * guarantee the value returned fits in that type, relying on
 * -Wshift-count-overflow compiler check to detect incompatible arguments.
 * For example, all these create build errors or warnings:
 *
 * - GENMASK(15, 20): wrong argument order
 * - GENMASK(72, 15): doesn't fit unsigned long
 * - GENMASK_U32(33, 15): doesn't fit in a u32
 */
#define GENMASK_TYPE(t, h, l)					\
	((t)(GENMASK_INPUT_CHECK(h, l) +			\
	     (type_max(t) << (l) &				\
	      type_max(t) >> (BITS_PER_TYPE(t) - 1 - (h)))))

#define GENMASK_U8(h, l)	GENMASK_TYPE(u8, h, l)
#define GENMASK_U16(h, l)	GENMASK_TYPE(u16, h, l)
#define GENMASK_U32(h, l)	GENMASK_TYPE(u32, h, l)
#define GENMASK_U64(h, l)	GENMASK_TYPE(u64, h, l)

/*
 * Fixed-type variants of BIT(), with additional checks like GENMASK_TYPE(). The
 * following examples generate compiler warnings due to -Wshift-count-overflow:
 *
 * - BIT_U8(8)
 * - BIT_U32(-1)
 * - BIT_U32(40)
 */
#define BIT_INPUT_CHECK(type, nr) \
	BUILD_BUG_ON_ZERO(const_true((nr) >= BITS_PER_TYPE(type)))

#define BIT_TYPE(type, nr) ((type)(BIT_INPUT_CHECK(type, nr) + BIT_ULL(nr)))

#define BIT_U8(nr)	BIT_TYPE(u8, nr)
#define BIT_U16(nr)	BIT_TYPE(u16, nr)
#define BIT_U32(nr)	BIT_TYPE(u32, nr)
#define BIT_U64(nr)	BIT_TYPE(u64, nr)

#else /* defined(__ASSEMBLY__) */

/*
 * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
 * disable the input check if that is the case.
 */
#define GENMASK_INPUT_CHECK(h, l) 0

#endif /* !defined(__ASSEMBLY__) */

#define GENMASK(h, l) \
	(GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
#define GENMASK_ULL(h, l) \
	(GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))

#if !defined(__ASSEMBLY__)
/*
 * Missing asm support
 *
 * __GENMASK_U128() depends on _BIT128() which would not work
 * in the asm code, as it shifts an 'unsigned __int128' data
 * type instead of direct representation of 128 bit constants
 * such as long and unsigned long. The fundamental problem is
 * that a 128 bit constant will get silently truncated by the
 * gcc compiler.
 */
#define GENMASK_U128(h, l) \
	(GENMASK_INPUT_CHECK(h, l) + __GENMASK_U128(h, l))
#endif

#endif	/* __LINUX_BITS_H */
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef __LINUX_BITS_H
	3	#define __LINUX_BITS_H
	4
	5	#include <linux/const.h>
	6	#include <vdso/bits.h>
	7	#include <uapi/linux/bits.h>
	8	#include <asm/bitsperlong.h>
	9
	10	#define BIT_MASK(nr) (UL(1) << ((nr) % BITS_PER_LONG))
	11	#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
	12	#define BIT_ULL_MASK(nr) (ULL(1) << ((nr) % BITS_PER_LONG_LONG))
	13	#define BIT_ULL_WORD(nr) ((nr) / BITS_PER_LONG_LONG)
	14	#define BITS_PER_BYTE 8
	15	#define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
	16
	17	/*
	18	* Create a contiguous bitmask starting at bit position @l and ending at
	19	* position @h. For example
	20	* GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
	21	*/
	22	#if !defined(__ASSEMBLY__)
	23
	24	/*
	25	* Missing asm support
	26	*
	27	* GENMASK_U() and BIT_U() depend on BITS_PER_TYPE() which relies on sizeof(),
	28	* something not available in asm. Nevertheless, fixed width integers is a C
	29	* concept. Assembly code can rely on the long and long long versions instead.
	30	*/
	31
	32	#include <linux/build_bug.h>
	33	#include <linux/compiler.h>
	34	#include <linux/overflow.h>
	35
	36	#define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h)))
	37
	38	/*
	39	* Generate a mask for the specified type @t. Additional checks are made to
	40	* guarantee the value returned fits in that type, relying on
	41	* -Wshift-count-overflow compiler check to detect incompatible arguments.
	42	* For example, all these create build errors or warnings:
	43	*
	44	* - GENMASK(15, 20): wrong argument order
	45	* - GENMASK(72, 15): doesn't fit unsigned long
	46	* - GENMASK_U32(33, 15): doesn't fit in a u32
	47	*/
	48	#define GENMASK_TYPE(t, h, l) \
	49	((t)(GENMASK_INPUT_CHECK(h, l) + \
	50	(type_max(t) << (l) & \
	51	type_max(t) >> (BITS_PER_TYPE(t) - 1 - (h)))))
	52
	53	#define GENMASK_U8(h, l) GENMASK_TYPE(u8, h, l)
	54	#define GENMASK_U16(h, l) GENMASK_TYPE(u16, h, l)
	55	#define GENMASK_U32(h, l) GENMASK_TYPE(u32, h, l)
	56	#define GENMASK_U64(h, l) GENMASK_TYPE(u64, h, l)
	57
	58	/*
	59	* Fixed-type variants of BIT(), with additional checks like GENMASK_TYPE(). The
	60	* following examples generate compiler warnings due to -Wshift-count-overflow:
	61	*
	62	* - BIT_U8(8)
	63	* - BIT_U32(-1)
	64	* - BIT_U32(40)
	65	*/
	66	#define BIT_INPUT_CHECK(type, nr) \
	67	BUILD_BUG_ON_ZERO(const_true((nr) >= BITS_PER_TYPE(type)))
	68
	69	#define BIT_TYPE(type, nr) ((type)(BIT_INPUT_CHECK(type, nr) + BIT_ULL(nr)))
	70
	71	#define BIT_U8(nr) BIT_TYPE(u8, nr)
	72	#define BIT_U16(nr) BIT_TYPE(u16, nr)
	73	#define BIT_U32(nr) BIT_TYPE(u32, nr)
	74	#define BIT_U64(nr) BIT_TYPE(u64, nr)
	75
	76	#else /* defined(__ASSEMBLY__) */
	77
	78	/*
	79	* BUILD_BUG_ON_ZERO is not available in h files included from asm files,
	80	* disable the input check if that is the case.
	81	*/
	82	#define GENMASK_INPUT_CHECK(h, l) 0
	83
	84	#endif /* !defined(__ASSEMBLY__) */
	85
	86	#define GENMASK(h, l) \
	87	(GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
	88	#define GENMASK_ULL(h, l) \
	89	(GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))
	90
	91	#if !defined(__ASSEMBLY__)
	92	/*
	93	* Missing asm support
	94	*
	95	* __GENMASK_U128() depends on _BIT128() which would not work
	96	* in the asm code, as it shifts an 'unsigned __int128' data
	97	* type instead of direct representation of 128 bit constants
	98	* such as long and unsigned long. The fundamental problem is
	99	* that a 128 bit constant will get silently truncated by the
	100	* gcc compiler.
	101	*/
	102	#define GENMASK_U128(h, l) \
	103	(GENMASK_INPUT_CHECK(h, l) + __GENMASK_U128(h, l))
	104	#endif
	105
	106	#endif /* __LINUX_BITS_H */