1 /* 2 * Copyright (c) 2011 The Chromium OS Authors. 3 * 4 * Modified from Linux arch/arm/include/asm/bitops.h 5 * 6 * Copyright 1995, Russell King. 7 * Various bits and pieces copyrights include: 8 * Linus Torvalds (test_bit). 9 * 10 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). 11 * 12 * Please note that the code in this file should never be included 13 * from user space. Many of these are not implemented in assembler 14 * since they would be too costly. Also, they require priviledged 15 * instructions (which are not available from user mode) to ensure 16 * that they are atomic. 17 */ 18 19 #ifndef __ASM_SANDBOX_BITOPS_H 20 #define __ASM_SANDBOX_BITOPS_H 21 22 #include <linux/compiler.h> 23 #include <asm/system.h> 24 #include <asm-generic/bitops/fls.h> 25 #include <asm-generic/bitops/__fls.h> 26 #include <asm-generic/bitops/fls64.h> 27 #include <asm-generic/bitops/__ffs.h> 28 29 #ifdef __KERNEL__ 30 31 #define smp_mb__before_clear_bit() do { } while (0) 32 #define smp_mb__after_clear_bit() do { } while (0) 33 34 /* 35 * Function prototypes to keep gcc -Wall happy. 36 */ 37 extern void set_bit(int nr, void *addr); 38 39 extern void clear_bit(int nr, void *addr); 40 41 extern void change_bit(int nr, void *addr); 42 43 static inline void __change_bit(int nr, void *addr) 44 { 45 unsigned long mask = BIT_MASK(nr); 46 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 47 48 *p ^= mask; 49 } 50 51 static inline int __test_and_set_bit(int nr, void *addr) 52 { 53 unsigned long mask = BIT_MASK(nr); 54 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 55 unsigned long old = *p; 56 57 *p = old | mask; 58 return (old & mask) != 0; 59 } 60 61 static inline int test_and_set_bit(int nr, void *addr) 62 { 63 unsigned long __always_unused flags; 64 int out; 65 66 local_irq_save(flags); 67 out = __test_and_set_bit(nr, addr); 68 local_irq_restore(flags); 69 70 return out; 71 } 72 73 static inline int __test_and_clear_bit(int nr, void *addr) 74 { 75 unsigned long mask = BIT_MASK(nr); 76 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 77 unsigned long old = *p; 78 79 *p = old & ~mask; 80 return (old & mask) != 0; 81 } 82 83 static inline int test_and_clear_bit(int nr, void *addr) 84 { 85 unsigned long __always_unused flags; 86 int out; 87 88 local_irq_save(flags); 89 out = __test_and_clear_bit(nr, addr); 90 local_irq_restore(flags); 91 92 return out; 93 } 94 95 extern int test_and_change_bit(int nr, void *addr); 96 97 static inline int __test_and_change_bit(int nr, void *addr) 98 { 99 unsigned long mask = BIT_MASK(nr); 100 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 101 unsigned long old = *p; 102 103 *p = old ^ mask; 104 return (old & mask) != 0; 105 } 106 107 extern int find_first_zero_bit(void *addr, unsigned size); 108 extern int find_next_zero_bit(void *addr, int size, int offset); 109 110 /* 111 * This routine doesn't need to be atomic. 112 */ 113 static inline int test_bit(int nr, const void *addr) 114 { 115 return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7)); 116 } 117 118 /* 119 * ffz = Find First Zero in word. Undefined if no zero exists, 120 * so code should check against ~0UL first.. 121 */ 122 static inline unsigned long ffz(unsigned long word) 123 { 124 int k; 125 126 word = ~word; 127 k = 31; 128 if (word & 0x0000ffff) { 129 k -= 16; word <<= 16; 130 } 131 if (word & 0x00ff0000) { 132 k -= 8; word <<= 8; 133 } 134 if (word & 0x0f000000) { 135 k -= 4; word <<= 4; 136 } 137 if (word & 0x30000000) { 138 k -= 2; word <<= 2; 139 } 140 if (word & 0x40000000) 141 k -= 1; 142 return k; 143 } 144 145 /* 146 * hweightN: returns the hamming weight (i.e. the number 147 * of bits set) of a N-bit word 148 */ 149 150 #define hweight32(x) generic_hweight32(x) 151 #define hweight16(x) generic_hweight16(x) 152 #define hweight8(x) generic_hweight8(x) 153 154 #define ext2_set_bit test_and_set_bit 155 #define ext2_clear_bit test_and_clear_bit 156 #define ext2_test_bit test_bit 157 #define ext2_find_first_zero_bit find_first_zero_bit 158 #define ext2_find_next_zero_bit find_next_zero_bit 159 160 /* Bitmap functions for the minix filesystem. */ 161 #define minix_test_and_set_bit(nr, addr) test_and_set_bit(nr, addr) 162 #define minix_set_bit(nr, addr) set_bit(nr, addr) 163 #define minix_test_and_clear_bit(nr, addr) test_and_clear_bit(nr, addr) 164 #define minix_test_bit(nr, addr) test_bit(nr, addr) 165 #define minix_find_first_zero_bit(addr, size) find_first_zero_bit(addr, size) 166 167 #endif /* __KERNEL__ */ 168 169 #endif /* _ARM_BITOPS_H */ 170