bitops.h (7590B)
1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * Copyright 1995, Russell King. 4 * Various bits and pieces copyrights include: 5 * Linus Torvalds (test_bit). 6 * Big endian support: Copyright 2001, Nicolas Pitre 7 * reworked by rmk. 8 * 9 * bit 0 is the LSB of an "unsigned long" quantity. 10 * 11 * Please note that the code in this file should never be included 12 * from user space. Many of these are not implemented in assembler 13 * since they would be too costly. Also, they require privileged 14 * instructions (which are not available from user mode) to ensure 15 * that they are atomic. 16 */ 17 18#ifndef __ASM_ARM_BITOPS_H 19#define __ASM_ARM_BITOPS_H 20 21#ifdef __KERNEL__ 22 23#ifndef _LINUX_BITOPS_H 24#error only <linux/bitops.h> can be included directly 25#endif 26 27#include <linux/compiler.h> 28#include <linux/irqflags.h> 29#include <asm/barrier.h> 30 31/* 32 * These functions are the basis of our bit ops. 33 * 34 * First, the atomic bitops. These use native endian. 35 */ 36static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p) 37{ 38 unsigned long flags; 39 unsigned long mask = BIT_MASK(bit); 40 41 p += BIT_WORD(bit); 42 43 raw_local_irq_save(flags); 44 *p |= mask; 45 raw_local_irq_restore(flags); 46} 47 48static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p) 49{ 50 unsigned long flags; 51 unsigned long mask = BIT_MASK(bit); 52 53 p += BIT_WORD(bit); 54 55 raw_local_irq_save(flags); 56 *p &= ~mask; 57 raw_local_irq_restore(flags); 58} 59 60static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p) 61{ 62 unsigned long flags; 63 unsigned long mask = BIT_MASK(bit); 64 65 p += BIT_WORD(bit); 66 67 raw_local_irq_save(flags); 68 *p ^= mask; 69 raw_local_irq_restore(flags); 70} 71 72static inline int 73____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p) 74{ 75 unsigned long flags; 76 unsigned int res; 77 unsigned long mask = BIT_MASK(bit); 78 79 p += BIT_WORD(bit); 80 81 raw_local_irq_save(flags); 82 res = *p; 83 *p = res | mask; 84 raw_local_irq_restore(flags); 85 86 return (res & mask) != 0; 87} 88 89static inline int 90____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p) 91{ 92 unsigned long flags; 93 unsigned int res; 94 unsigned long mask = BIT_MASK(bit); 95 96 p += BIT_WORD(bit); 97 98 raw_local_irq_save(flags); 99 res = *p; 100 *p = res & ~mask; 101 raw_local_irq_restore(flags); 102 103 return (res & mask) != 0; 104} 105 106static inline int 107____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p) 108{ 109 unsigned long flags; 110 unsigned int res; 111 unsigned long mask = BIT_MASK(bit); 112 113 p += BIT_WORD(bit); 114 115 raw_local_irq_save(flags); 116 res = *p; 117 *p = res ^ mask; 118 raw_local_irq_restore(flags); 119 120 return (res & mask) != 0; 121} 122 123#include <asm-generic/bitops/non-atomic.h> 124 125/* 126 * A note about Endian-ness. 127 * ------------------------- 128 * 129 * When the ARM is put into big endian mode via CR15, the processor 130 * merely swaps the order of bytes within words, thus: 131 * 132 * ------------ physical data bus bits ----------- 133 * D31 ... D24 D23 ... D16 D15 ... D8 D7 ... D0 134 * little byte 3 byte 2 byte 1 byte 0 135 * big byte 0 byte 1 byte 2 byte 3 136 * 137 * This means that reading a 32-bit word at address 0 returns the same 138 * value irrespective of the endian mode bit. 139 * 140 * Peripheral devices should be connected with the data bus reversed in 141 * "Big Endian" mode. ARM Application Note 61 is applicable, and is 142 * available from http://www.arm.com/. 143 * 144 * The following assumes that the data bus connectivity for big endian 145 * mode has been followed. 146 * 147 * Note that bit 0 is defined to be 32-bit word bit 0, not byte 0 bit 0. 148 */ 149 150/* 151 * Native endian assembly bitops. nr = 0 -> word 0 bit 0. 152 */ 153extern void _set_bit(int nr, volatile unsigned long * p); 154extern void _clear_bit(int nr, volatile unsigned long * p); 155extern void _change_bit(int nr, volatile unsigned long * p); 156extern int _test_and_set_bit(int nr, volatile unsigned long * p); 157extern int _test_and_clear_bit(int nr, volatile unsigned long * p); 158extern int _test_and_change_bit(int nr, volatile unsigned long * p); 159 160/* 161 * Little endian assembly bitops. nr = 0 -> byte 0 bit 0. 162 */ 163extern int _find_first_zero_bit_le(const unsigned long *p, unsigned size); 164extern int _find_next_zero_bit_le(const unsigned long *p, int size, int offset); 165extern int _find_first_bit_le(const unsigned long *p, unsigned size); 166extern int _find_next_bit_le(const unsigned long *p, int size, int offset); 167 168/* 169 * Big endian assembly bitops. nr = 0 -> byte 3 bit 0. 170 */ 171extern int _find_first_zero_bit_be(const unsigned long *p, unsigned size); 172extern int _find_next_zero_bit_be(const unsigned long *p, int size, int offset); 173extern int _find_first_bit_be(const unsigned long *p, unsigned size); 174extern int _find_next_bit_be(const unsigned long *p, int size, int offset); 175 176#ifndef CONFIG_SMP 177/* 178 * The __* form of bitops are non-atomic and may be reordered. 179 */ 180#define ATOMIC_BITOP(name,nr,p) \ 181 (__builtin_constant_p(nr) ? ____atomic_##name(nr, p) : _##name(nr,p)) 182#else 183#define ATOMIC_BITOP(name,nr,p) _##name(nr,p) 184#endif 185 186/* 187 * Native endian atomic definitions. 188 */ 189#define set_bit(nr,p) ATOMIC_BITOP(set_bit,nr,p) 190#define clear_bit(nr,p) ATOMIC_BITOP(clear_bit,nr,p) 191#define change_bit(nr,p) ATOMIC_BITOP(change_bit,nr,p) 192#define test_and_set_bit(nr,p) ATOMIC_BITOP(test_and_set_bit,nr,p) 193#define test_and_clear_bit(nr,p) ATOMIC_BITOP(test_and_clear_bit,nr,p) 194#define test_and_change_bit(nr,p) ATOMIC_BITOP(test_and_change_bit,nr,p) 195 196#ifndef __ARMEB__ 197/* 198 * These are the little endian, atomic definitions. 199 */ 200#define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz) 201#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off) 202#define find_first_bit(p,sz) _find_first_bit_le(p,sz) 203#define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off) 204 205#else 206/* 207 * These are the big endian, atomic definitions. 208 */ 209#define find_first_zero_bit(p,sz) _find_first_zero_bit_be(p,sz) 210#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_be(p,sz,off) 211#define find_first_bit(p,sz) _find_first_bit_be(p,sz) 212#define find_next_bit(p,sz,off) _find_next_bit_be(p,sz,off) 213 214#endif 215 216#if __LINUX_ARM_ARCH__ < 5 217 218#include <asm-generic/bitops/__fls.h> 219#include <asm-generic/bitops/__ffs.h> 220#include <asm-generic/bitops/fls.h> 221#include <asm-generic/bitops/ffs.h> 222 223#else 224 225/* 226 * On ARMv5 and above, the gcc built-ins may rely on the clz instruction 227 * and produce optimal inlined code in all cases. On ARMv7 it is even 228 * better by also using the rbit instruction. 229 */ 230#include <asm-generic/bitops/builtin-__fls.h> 231#include <asm-generic/bitops/builtin-__ffs.h> 232#include <asm-generic/bitops/builtin-fls.h> 233#include <asm-generic/bitops/builtin-ffs.h> 234 235#endif 236 237#include <asm-generic/bitops/ffz.h> 238 239#include <asm-generic/bitops/fls64.h> 240 241#include <asm-generic/bitops/sched.h> 242#include <asm-generic/bitops/hweight.h> 243#include <asm-generic/bitops/lock.h> 244 245#ifdef __ARMEB__ 246 247static inline int find_first_zero_bit_le(const void *p, unsigned size) 248{ 249 return _find_first_zero_bit_le(p, size); 250} 251#define find_first_zero_bit_le find_first_zero_bit_le 252 253static inline int find_next_zero_bit_le(const void *p, int size, int offset) 254{ 255 return _find_next_zero_bit_le(p, size, offset); 256} 257#define find_next_zero_bit_le find_next_zero_bit_le 258 259static inline int find_next_bit_le(const void *p, int size, int offset) 260{ 261 return _find_next_bit_le(p, size, offset); 262} 263#define find_next_bit_le find_next_bit_le 264 265#endif 266 267#include <asm-generic/bitops/le.h> 268 269/* 270 * Ext2 is defined to use little-endian byte ordering. 271 */ 272#include <asm-generic/bitops/ext2-atomic-setbit.h> 273 274#endif /* __KERNEL__ */ 275 276#endif /* _ARM_BITOPS_H */