xref: /linux-6.15/include/linux/bitops.h (revision 9d64fc08)
1 #ifndef _LINUX_BITOPS_H
2 #define _LINUX_BITOPS_H
3 #include <asm/types.h>
4 
5 #ifdef	__KERNEL__
6 #define BIT(nr)			(1UL << (nr))
7 #define BIT_ULL(nr)		(1ULL << (nr))
8 #define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
9 #define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
10 #define BIT_ULL_MASK(nr)	(1ULL << ((nr) % BITS_PER_LONG_LONG))
11 #define BIT_ULL_WORD(nr)	((nr) / BITS_PER_LONG_LONG)
12 #define BITS_PER_BYTE		8
13 #define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
14 #endif
15 
16 /*
17  * Create a contiguous bitmask starting at bit position @l and ending at
18  * position @h. For example
19  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
20  */
21 #define GENMASK(h, l) \
22 	(((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
23 
24 #define GENMASK_ULL(h, l) \
25 	(((~0ULL) - (1ULL << (l)) + 1) & \
26 	 (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
27 
28 extern unsigned int __sw_hweight8(unsigned int w);
29 extern unsigned int __sw_hweight16(unsigned int w);
30 extern unsigned int __sw_hweight32(unsigned int w);
31 extern unsigned long __sw_hweight64(__u64 w);
32 
33 /*
34  * Include this here because some architectures need generic_ffs/fls in
35  * scope
36  */
37 #include <asm/bitops.h>
38 
39 #define for_each_set_bit(bit, addr, size) \
40 	for ((bit) = find_first_bit((addr), (size));		\
41 	     (bit) < (size);					\
42 	     (bit) = find_next_bit((addr), (size), (bit) + 1))
43 
44 /* same as for_each_set_bit() but use bit as value to start with */
45 #define for_each_set_bit_from(bit, addr, size) \
46 	for ((bit) = find_next_bit((addr), (size), (bit));	\
47 	     (bit) < (size);					\
48 	     (bit) = find_next_bit((addr), (size), (bit) + 1))
49 
50 #define for_each_clear_bit(bit, addr, size) \
51 	for ((bit) = find_first_zero_bit((addr), (size));	\
52 	     (bit) < (size);					\
53 	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
54 
55 /* same as for_each_clear_bit() but use bit as value to start with */
56 #define for_each_clear_bit_from(bit, addr, size) \
57 	for ((bit) = find_next_zero_bit((addr), (size), (bit));	\
58 	     (bit) < (size);					\
59 	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
60 
61 static inline int get_bitmask_order(unsigned int count)
62 {
63 	int order;
64 
65 	order = fls(count);
66 	return order;	/* We could be slightly more clever with -1 here... */
67 }
68 
69 static __always_inline unsigned long hweight_long(unsigned long w)
70 {
71 	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
72 }
73 
74 /**
75  * rol64 - rotate a 64-bit value left
76  * @word: value to rotate
77  * @shift: bits to roll
78  */
79 static inline __u64 rol64(__u64 word, unsigned int shift)
80 {
81 	return (word << shift) | (word >> (64 - shift));
82 }
83 
84 /**
85  * ror64 - rotate a 64-bit value right
86  * @word: value to rotate
87  * @shift: bits to roll
88  */
89 static inline __u64 ror64(__u64 word, unsigned int shift)
90 {
91 	return (word >> shift) | (word << (64 - shift));
92 }
93 
94 /**
95  * rol32 - rotate a 32-bit value left
96  * @word: value to rotate
97  * @shift: bits to roll
98  */
99 static inline __u32 rol32(__u32 word, unsigned int shift)
100 {
101 	return (word << shift) | (word >> ((-shift) & 31));
102 }
103 
104 /**
105  * ror32 - rotate a 32-bit value right
106  * @word: value to rotate
107  * @shift: bits to roll
108  */
109 static inline __u32 ror32(__u32 word, unsigned int shift)
110 {
111 	return (word >> shift) | (word << (32 - shift));
112 }
113 
114 /**
115  * rol16 - rotate a 16-bit value left
116  * @word: value to rotate
117  * @shift: bits to roll
118  */
119 static inline __u16 rol16(__u16 word, unsigned int shift)
120 {
121 	return (word << shift) | (word >> (16 - shift));
122 }
123 
124 /**
125  * ror16 - rotate a 16-bit value right
126  * @word: value to rotate
127  * @shift: bits to roll
128  */
129 static inline __u16 ror16(__u16 word, unsigned int shift)
130 {
131 	return (word >> shift) | (word << (16 - shift));
132 }
133 
134 /**
135  * rol8 - rotate an 8-bit value left
136  * @word: value to rotate
137  * @shift: bits to roll
138  */
139 static inline __u8 rol8(__u8 word, unsigned int shift)
140 {
141 	return (word << shift) | (word >> (8 - shift));
142 }
143 
144 /**
145  * ror8 - rotate an 8-bit value right
146  * @word: value to rotate
147  * @shift: bits to roll
148  */
149 static inline __u8 ror8(__u8 word, unsigned int shift)
150 {
151 	return (word >> shift) | (word << (8 - shift));
152 }
153 
154 /**
155  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
156  * @value: value to sign extend
157  * @index: 0 based bit index (0<=index<32) to sign bit
158  *
159  * This is safe to use for 16- and 8-bit types as well.
160  */
161 static inline __s32 sign_extend32(__u32 value, int index)
162 {
163 	__u8 shift = 31 - index;
164 	return (__s32)(value << shift) >> shift;
165 }
166 
167 /**
168  * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
169  * @value: value to sign extend
170  * @index: 0 based bit index (0<=index<64) to sign bit
171  */
172 static inline __s64 sign_extend64(__u64 value, int index)
173 {
174 	__u8 shift = 63 - index;
175 	return (__s64)(value << shift) >> shift;
176 }
177 
178 static inline unsigned fls_long(unsigned long l)
179 {
180 	if (sizeof(l) == 4)
181 		return fls(l);
182 	return fls64(l);
183 }
184 
185 static inline int get_count_order(unsigned int count)
186 {
187 	int order;
188 
189 	order = fls(count) - 1;
190 	if (count & (count - 1))
191 		order++;
192 	return order;
193 }
194 
195 /**
196  * get_count_order_long - get order after rounding @l up to power of 2
197  * @l: parameter
198  *
199  * it is same as get_count_order() but with long type parameter
200  */
201 static inline int get_count_order_long(unsigned long l)
202 {
203 	if (l == 0UL)
204 		return -1;
205 	else if (l & (l - 1UL))
206 		return (int)fls_long(l);
207 	else
208 		return (int)fls_long(l) - 1;
209 }
210 
211 /**
212  * __ffs64 - find first set bit in a 64 bit word
213  * @word: The 64 bit word
214  *
215  * On 64 bit arches this is a synomyn for __ffs
216  * The result is not defined if no bits are set, so check that @word
217  * is non-zero before calling this.
218  */
219 static inline unsigned long __ffs64(u64 word)
220 {
221 #if BITS_PER_LONG == 32
222 	if (((u32)word) == 0UL)
223 		return __ffs((u32)(word >> 32)) + 32;
224 #elif BITS_PER_LONG != 64
225 #error BITS_PER_LONG not 32 or 64
226 #endif
227 	return __ffs((unsigned long)word);
228 }
229 
230 #ifdef __KERNEL__
231 
232 #ifndef set_mask_bits
233 #define set_mask_bits(ptr, _mask, _bits)	\
234 ({								\
235 	const typeof(*ptr) mask = (_mask), bits = (_bits);	\
236 	typeof(*ptr) old, new;					\
237 								\
238 	do {							\
239 		old = ACCESS_ONCE(*ptr);			\
240 		new = (old & ~mask) | bits;			\
241 	} while (cmpxchg(ptr, old, new) != old);		\
242 								\
243 	new;							\
244 })
245 #endif
246 
247 #ifndef bit_clear_unless
248 #define bit_clear_unless(ptr, _clear, _test)	\
249 ({								\
250 	const typeof(*ptr) clear = (_clear), test = (_test);	\
251 	typeof(*ptr) old, new;					\
252 								\
253 	do {							\
254 		old = ACCESS_ONCE(*ptr);			\
255 		new = old & ~clear;				\
256 	} while (!(old & test) &&				\
257 		 cmpxchg(ptr, old, new) != old);		\
258 								\
259 	!(old & test);						\
260 })
261 #endif
262 
263 #ifndef find_last_bit
264 /**
265  * find_last_bit - find the last set bit in a memory region
266  * @addr: The address to start the search at
267  * @size: The number of bits to search
268  *
269  * Returns the bit number of the last set bit, or size.
270  */
271 extern unsigned long find_last_bit(const unsigned long *addr,
272 				   unsigned long size);
273 #endif
274 
275 #endif /* __KERNEL__ */
276 #endif
277