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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178/* SPDX-License-Identifier: GPL-2.0-only *//* * Copyright (C) 2014 Felix Fietkau <nbd@nbd.name> * Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> */
#ifndef _LINUX_BITFIELD_H#define _LINUX_BITFIELD_H
#include <linux/build_bug.h>#include <linux/kernel.h>#include <asm/byteorder.h>
/* * Bitfield access macros * * FIELD_{GET,PREP} macros take as first parameter shifted mask * from which they extract the base mask and shift amount. * Mask must be a compilation time constant. * * Example: * * #define REG_FIELD_A GENMASK(6, 0) * #define REG_FIELD_B BIT(7) * #define REG_FIELD_C GENMASK(15, 8) * #define REG_FIELD_D GENMASK(31, 16) * * Get: * a = FIELD_GET(REG_FIELD_A, reg); * b = FIELD_GET(REG_FIELD_B, reg); * * Set: * reg = FIELD_PREP(REG_FIELD_A, 1) | * FIELD_PREP(REG_FIELD_B, 0) | * FIELD_PREP(REG_FIELD_C, c) | * FIELD_PREP(REG_FIELD_D, 0x40); * * Modify: * reg &= ~REG_FIELD_C; * reg |= FIELD_PREP(REG_FIELD_C, c); */
#define __bf_shf(x) (__builtin_ffsll(x) - 1)
#define __scalar_type_to_unsigned_cases(type) \ unsigned type: (unsigned type)0, \ signed type: (unsigned type)0
#define __unsigned_scalar_typeof(x) typeof( \ _Generic((x), \ char: (unsigned char)0, \ __scalar_type_to_unsigned_cases(char), \ __scalar_type_to_unsigned_cases(short), \ __scalar_type_to_unsigned_cases(int), \ __scalar_type_to_unsigned_cases(long), \ __scalar_type_to_unsigned_cases(long long), \ default: (x)))
#define __bf_cast_unsigned(type, x) ((__unsigned_scalar_typeof(type))(x))
#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \ ({ \ BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \ _pfx "mask is not constant"); \ BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero"); \ BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \ ~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \ _pfx "value too large for the field"); \ BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \ __bf_cast_unsigned(_reg, ~0ull), \ _pfx "type of reg too small for mask"); \ __BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \ (1ULL << __bf_shf(_mask))); \ })
/** * FIELD_MAX() - produce the maximum value representable by a field * @_mask: shifted mask defining the field's length and position * * FIELD_MAX() returns the maximum value that can be held in the field * specified by @_mask. */#define FIELD_MAX(_mask) \ ({ \ __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: "); \ (typeof(_mask))((_mask) >> __bf_shf(_mask)); \ })
/** * FIELD_FIT() - check if value fits in the field * @_mask: shifted mask defining the field's length and position * @_val: value to test against the field * * Return: true if @_val can fit inside @_mask, false if @_val is too big. */#define FIELD_FIT(_mask, _val) \ ({ \ __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_FIT: "); \ !((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \ })
/** * FIELD_PREP() - prepare a bitfield element * @_mask: shifted mask defining the field's length and position * @_val: value to put in the field * * FIELD_PREP() masks and shifts up the value. The result should * be combined with other fields of the bitfield using logical OR. */#define FIELD_PREP(_mask, _val) \ ({ \ __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \ ((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask); \ })
/** * FIELD_GET() - extract a bitfield element * @_mask: shifted mask defining the field's length and position * @_reg: value of entire bitfield * * FIELD_GET() extracts the field specified by @_mask from the * bitfield passed in as @_reg by masking and shifting it down. */#define FIELD_GET(_mask, _reg) \ ({ \ __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \ (typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \ })
extern void __compiletime_error("value doesn't fit into mask")__field_overflow(void);extern void __compiletime_error("bad bitfield mask")__bad_mask(void);static __always_inline u64 field_multiplier(u64 field){ if ((field | (field - 1)) & ((field | (field - 1)) + 1)) __bad_mask(); return field & -field;}static __always_inline u64 field_mask(u64 field){ return field / field_multiplier(field);}#define field_max(field) ((typeof(field))field_mask(field))#define ____MAKE_OP(type,base,to,from) \static __always_inline __##type type##_encode_bits(base v, base field) \{ \ if (__builtin_constant_p(v) && (v & ~field_mask(field))) \ __field_overflow(); \ return to((v & field_mask(field)) * field_multiplier(field)); \} \static __always_inline __##type type##_replace_bits(__##type old, \ base val, base field) \{ \ return (old & ~to(field)) | type##_encode_bits(val, field); \} \static __always_inline void type##p_replace_bits(__##type *p, \ base val, base field) \{ \ *p = (*p & ~to(field)) | type##_encode_bits(val, field); \} \static __always_inline base type##_get_bits(__##type v, base field) \{ \ return (from(v) & field)/field_multiplier(field); \}#define __MAKE_OP(size) \ ____MAKE_OP(le##size,u##size,cpu_to_le##size,le##size##_to_cpu) \ ____MAKE_OP(be##size,u##size,cpu_to_be##size,be##size##_to_cpu) \ ____MAKE_OP(u##size,u##size,,)____MAKE_OP(u8,u8,,)__MAKE_OP(16)__MAKE_OP(32)__MAKE_OP(64)#undef __MAKE_OP#undef ____MAKE_OP
#endif