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 25 #ifdef __KERNEL__ 26 27 #define smp_mb__before_clear_bit() do { } while (0) 28 #define smp_mb__after_clear_bit() do { } while (0) 29 30 /* 31 * Function prototypes to keep gcc -Wall happy. 32 */ 33 extern void set_bit(int nr, void *addr); 34 35 extern void clear_bit(int nr, void *addr); 36 37 extern void change_bit(int nr, void *addr); 38 39 static inline void __change_bit(int nr, void *addr) 40 { 41 unsigned long mask = BIT_MASK(nr); 42 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 43 44 *p ^= mask; 45 } 46 47 static inline int __test_and_set_bit(int nr, void *addr) 48 { 49 unsigned long mask = BIT_MASK(nr); 50 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 51 unsigned long old = *p; 52 53 *p = old | mask; 54 return (old & mask) != 0; 55 } 56 57 static inline int test_and_set_bit(int nr, void *addr) 58 { 59 unsigned long __always_unused flags; 60 int out; 61 62 local_irq_save(flags); 63 out = __test_and_set_bit(nr, addr); 64 local_irq_restore(flags); 65 66 return out; 67 } 68 69 static inline int __test_and_clear_bit(int nr, void *addr) 70 { 71 unsigned long mask = BIT_MASK(nr); 72 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 73 unsigned long old = *p; 74 75 *p = old & ~mask; 76 return (old & mask) != 0; 77 } 78 79 static inline int test_and_clear_bit(int nr, void *addr) 80 { 81 unsigned long __always_unused flags; 82 int out; 83 84 local_irq_save(flags); 85 out = __test_and_clear_bit(nr, addr); 86 local_irq_restore(flags); 87 88 return out; 89 } 90 91 extern int test_and_change_bit(int nr, void *addr); 92 93 static inline int __test_and_change_bit(int nr, void *addr) 94 { 95 unsigned long mask = BIT_MASK(nr); 96 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 97 unsigned long old = *p; 98 99 *p = old ^ mask; 100 return (old & mask) != 0; 101 } 102 103 extern int find_first_zero_bit(void *addr, unsigned size); 104 extern int find_next_zero_bit(void *addr, int size, int offset); 105 106 /* 107 * This routine doesn't need to be atomic. 108 */ 109 static inline int test_bit(int nr, const void *addr) 110 { 111 return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7)); 112 } 113 114 /* 115 * ffz = Find First Zero in word. Undefined if no zero exists, 116 * so code should check against ~0UL first.. 117 */ 118 static inline unsigned long ffz(unsigned long word) 119 { 120 int k; 121 122 word = ~word; 123 k = 31; 124 if (word & 0x0000ffff) { 125 k -= 16; word <<= 16; 126 } 127 if (word & 0x00ff0000) { 128 k -= 8; word <<= 8; 129 } 130 if (word & 0x0f000000) { 131 k -= 4; word <<= 4; 132 } 133 if (word & 0x30000000) { 134 k -= 2; word <<= 2; 135 } 136 if (word & 0x40000000) 137 k -= 1; 138 return k; 139 } 140 141 /* 142 * hweightN: returns the hamming weight (i.e. the number 143 * of bits set) of a N-bit word 144 */ 145 146 #define hweight32(x) generic_hweight32(x) 147 #define hweight16(x) generic_hweight16(x) 148 #define hweight8(x) generic_hweight8(x) 149 150 #define ext2_set_bit test_and_set_bit 151 #define ext2_clear_bit test_and_clear_bit 152 #define ext2_test_bit test_bit 153 #define ext2_find_first_zero_bit find_first_zero_bit 154 #define ext2_find_next_zero_bit find_next_zero_bit 155 156 /* Bitmap functions for the minix filesystem. */ 157 #define minix_test_and_set_bit(nr, addr) test_and_set_bit(nr, addr) 158 #define minix_set_bit(nr, addr) set_bit(nr, addr) 159 #define minix_test_and_clear_bit(nr, addr) test_and_clear_bit(nr, addr) 160 #define minix_test_bit(nr, addr) test_bit(nr, addr) 161 #define minix_find_first_zero_bit(addr, size) find_first_zero_bit(addr, size) 162 163 #endif /* __KERNEL__ */ 164 165 #endif /* _ARM_BITOPS_H */ 166