1 /* 2 * Copyright (c) 2011 The Chromium OS Authors. 3 * 4 * Copyright 1995, Russell King. 5 * Various bits and pieces copyrights include: 6 * Linus Torvalds (test_bit). 7 * 8 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). 9 * 10 * Please note that the code in this file should never be included 11 * from user space. Many of these are not implemented in assembler 12 * since they would be too costly. Also, they require priviledged 13 * instructions (which are not available from user mode) to ensure 14 * that they are atomic. 15 */ 16 17 #ifndef __ASM_SANDBOX_BITOPS_H 18 #define __ASM_SANDBOX_BITOPS_H 19 20 #include <asm/system.h> 21 22 #ifdef __KERNEL__ 23 24 #define smp_mb__before_clear_bit() do { } while (0) 25 #define smp_mb__after_clear_bit() do { } while (0) 26 27 /* 28 * Function prototypes to keep gcc -Wall happy. 29 */ 30 extern void set_bit(int nr, void *addr); 31 32 extern void clear_bit(int nr, void *addr); 33 34 extern void change_bit(int nr, void *addr); 35 36 static inline void __change_bit(int nr, void *addr) 37 { 38 unsigned long mask = BIT_MASK(nr); 39 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 40 41 *p ^= mask; 42 } 43 44 static inline int __test_and_set_bit(int nr, void *addr) 45 { 46 unsigned long mask = BIT_MASK(nr); 47 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 48 unsigned long old = *p; 49 50 *p = old | mask; 51 return (old & mask) != 0; 52 } 53 54 static inline int test_and_set_bit(int nr, void *addr) 55 { 56 unsigned long flags; 57 int out; 58 59 local_irq_save(flags); 60 out = __test_and_set_bit(nr, addr); 61 local_irq_restore(flags); 62 63 return out; 64 } 65 66 static inline int __test_and_clear_bit(int nr, void *addr) 67 { 68 unsigned long mask = BIT_MASK(nr); 69 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 70 unsigned long old = *p; 71 72 *p = old & ~mask; 73 return (old & mask) != 0; 74 } 75 76 static inline int test_and_clear_bit(int nr, void *addr) 77 { 78 unsigned long flags; 79 int out; 80 81 local_irq_save(flags); 82 out = __test_and_clear_bit(nr, addr); 83 local_irq_restore(flags); 84 85 return out; 86 } 87 88 extern int test_and_change_bit(int nr, void *addr); 89 90 static inline int __test_and_change_bit(int nr, void *addr) 91 { 92 unsigned long mask = BIT_MASK(nr); 93 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 94 unsigned long old = *p; 95 96 *p = old ^ mask; 97 return (old & mask) != 0; 98 } 99 100 extern int find_first_zero_bit(void *addr, unsigned size); 101 extern int find_next_zero_bit(void *addr, int size, int offset); 102 103 /* 104 * This routine doesn't need to be atomic. 105 */ 106 static inline int test_bit(int nr, const void *addr) 107 { 108 return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7)); 109 } 110 111 /* 112 * ffz = Find First Zero in word. Undefined if no zero exists, 113 * so code should check against ~0UL first.. 114 */ 115 static inline unsigned long ffz(unsigned long word) 116 { 117 int k; 118 119 word = ~word; 120 k = 31; 121 if (word & 0x0000ffff) { 122 k -= 16; word <<= 16; 123 } 124 if (word & 0x00ff0000) { 125 k -= 8; word <<= 8; 126 } 127 if (word & 0x0f000000) { 128 k -= 4; word <<= 4; 129 } 130 if (word & 0x30000000) { 131 k -= 2; word <<= 2; 132 } 133 if (word & 0x40000000) 134 k -= 1; 135 return k; 136 } 137 138 /* 139 * hweightN: returns the hamming weight (i.e. the number 140 * of bits set) of a N-bit word 141 */ 142 143 #define hweight32(x) generic_hweight32(x) 144 #define hweight16(x) generic_hweight16(x) 145 #define hweight8(x) generic_hweight8(x) 146 147 #define ext2_set_bit test_and_set_bit 148 #define ext2_clear_bit test_and_clear_bit 149 #define ext2_test_bit test_bit 150 #define ext2_find_first_zero_bit find_first_zero_bit 151 #define ext2_find_next_zero_bit find_next_zero_bit 152 153 /* Bitmap functions for the minix filesystem. */ 154 #define minix_test_and_set_bit(nr, addr) test_and_set_bit(nr, addr) 155 #define minix_set_bit(nr, addr) set_bit(nr, addr) 156 #define minix_test_and_clear_bit(nr, addr) test_and_clear_bit(nr, addr) 157 #define minix_test_bit(nr, addr) test_bit(nr, addr) 158 #define minix_find_first_zero_bit(addr, size) find_first_zero_bit(addr, size) 159 160 #endif /* __KERNEL__ */ 161 162 #endif /* _ARM_BITOPS_H */ 163