1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_BITOPS_H
3 #define _LINUX_BITOPS_H
4
5 #include <asm/types.h>
6 #include <linux/bits.h>
7 #include <linux/typecheck.h>
8
9 #include <uapi/linux/kernel.h>
10
11 #define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
12 #define BITS_TO_LONGS(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(long))
13 #define BITS_TO_U64(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u64))
14 #define BITS_TO_U32(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u32))
15 #define BITS_TO_BYTES(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(char))
16
17 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_BYTE)
18
19 extern unsigned int __sw_hweight8(unsigned int w);
20 extern unsigned int __sw_hweight16(unsigned int w);
21 extern unsigned int __sw_hweight32(unsigned int w);
22 extern unsigned long __sw_hweight64(__u64 w);
23
24 /*
25 * Defined here because those may be needed by architecture-specific static
26 * inlines.
27 */
28
29 #include <asm-generic/bitops/generic-non-atomic.h>
30
31 /*
32 * Many architecture-specific non-atomic bitops contain inline asm code and due
33 * to that the compiler can't optimize them to compile-time expressions or
34 * constants. In contrary, generic_*() helpers are defined in pure C and
35 * compilers optimize them just well.
36 * Therefore, to make `unsigned long foo = 0; __set_bit(BAR, &foo)` effectively
37 * equal to `unsigned long foo = BIT(BAR)`, pick the generic C alternative when
38 * the arguments can be resolved at compile time. That expression itself is a
39 * constant and doesn't bring any functional changes to the rest of cases.
40 * The casts to `uintptr_t` are needed to mitigate `-Waddress` warnings when
41 * passing a bitmap from .bss or .data (-> `!!addr` is always true).
42 */
43 #define bitop(op, nr, addr) \
44 ((__builtin_constant_p(nr) && \
45 __builtin_constant_p((uintptr_t)(addr) != (uintptr_t)NULL) && \
46 (uintptr_t)(addr) != (uintptr_t)NULL && \
47 __builtin_constant_p(*(const unsigned long *)(addr))) ? \
48 const##op(nr, addr) : op(nr, addr))
49
50 #define __set_bit(nr, addr) bitop(___set_bit, nr, addr)
51 #define __clear_bit(nr, addr) bitop(___clear_bit, nr, addr)
52 #define __change_bit(nr, addr) bitop(___change_bit, nr, addr)
53 #define __test_and_set_bit(nr, addr) bitop(___test_and_set_bit, nr, addr)
54 #define __test_and_clear_bit(nr, addr) bitop(___test_and_clear_bit, nr, addr)
55 #define __test_and_change_bit(nr, addr) bitop(___test_and_change_bit, nr, addr)
56 #define test_bit(nr, addr) bitop(_test_bit, nr, addr)
57 #define test_bit_acquire(nr, addr) bitop(_test_bit_acquire, nr, addr)
58
59 /*
60 * Include this here because some architectures need generic_ffs/fls in
61 * scope
62 */
63 #include <asm/bitops.h>
64
65 /* Check that the bitops prototypes are sane */
66 #define __check_bitop_pr(name) \
67 static_assert(__same_type(arch_##name, generic_##name) && \
68 __same_type(const_##name, generic_##name) && \
69 __same_type(_##name, generic_##name))
70
71 __check_bitop_pr(__set_bit);
72 __check_bitop_pr(__clear_bit);
73 __check_bitop_pr(__change_bit);
74 __check_bitop_pr(__test_and_set_bit);
75 __check_bitop_pr(__test_and_clear_bit);
76 __check_bitop_pr(__test_and_change_bit);
77 __check_bitop_pr(test_bit);
78 __check_bitop_pr(test_bit_acquire);
79
80 #undef __check_bitop_pr
81
get_bitmask_order(unsigned int count)82 static inline int get_bitmask_order(unsigned int count)
83 {
84 int order;
85
86 order = fls(count);
87 return order; /* We could be slightly more clever with -1 here... */
88 }
89
hweight_long(unsigned long w)90 static __always_inline unsigned long hweight_long(unsigned long w)
91 {
92 return sizeof(w) == 4 ? hweight32(w) : hweight64((__u64)w);
93 }
94
95 /**
96 * rol64 - rotate a 64-bit value left
97 * @word: value to rotate
98 * @shift: bits to roll
99 */
rol64(__u64 word,unsigned int shift)100 static inline __u64 rol64(__u64 word, unsigned int shift)
101 {
102 return (word << (shift & 63)) | (word >> ((-shift) & 63));
103 }
104
105 /**
106 * ror64 - rotate a 64-bit value right
107 * @word: value to rotate
108 * @shift: bits to roll
109 */
ror64(__u64 word,unsigned int shift)110 static inline __u64 ror64(__u64 word, unsigned int shift)
111 {
112 return (word >> (shift & 63)) | (word << ((-shift) & 63));
113 }
114
115 /**
116 * rol32 - rotate a 32-bit value left
117 * @word: value to rotate
118 * @shift: bits to roll
119 */
rol32(__u32 word,unsigned int shift)120 static inline __u32 rol32(__u32 word, unsigned int shift)
121 {
122 return (word << (shift & 31)) | (word >> ((-shift) & 31));
123 }
124
125 /**
126 * ror32 - rotate a 32-bit value right
127 * @word: value to rotate
128 * @shift: bits to roll
129 */
ror32(__u32 word,unsigned int shift)130 static inline __u32 ror32(__u32 word, unsigned int shift)
131 {
132 return (word >> (shift & 31)) | (word << ((-shift) & 31));
133 }
134
135 /**
136 * rol16 - rotate a 16-bit value left
137 * @word: value to rotate
138 * @shift: bits to roll
139 */
rol16(__u16 word,unsigned int shift)140 static inline __u16 rol16(__u16 word, unsigned int shift)
141 {
142 return (word << (shift & 15)) | (word >> ((-shift) & 15));
143 }
144
145 /**
146 * ror16 - rotate a 16-bit value right
147 * @word: value to rotate
148 * @shift: bits to roll
149 */
ror16(__u16 word,unsigned int shift)150 static inline __u16 ror16(__u16 word, unsigned int shift)
151 {
152 return (word >> (shift & 15)) | (word << ((-shift) & 15));
153 }
154
155 /**
156 * rol8 - rotate an 8-bit value left
157 * @word: value to rotate
158 * @shift: bits to roll
159 */
rol8(__u8 word,unsigned int shift)160 static inline __u8 rol8(__u8 word, unsigned int shift)
161 {
162 return (word << (shift & 7)) | (word >> ((-shift) & 7));
163 }
164
165 /**
166 * ror8 - rotate an 8-bit value right
167 * @word: value to rotate
168 * @shift: bits to roll
169 */
ror8(__u8 word,unsigned int shift)170 static inline __u8 ror8(__u8 word, unsigned int shift)
171 {
172 return (word >> (shift & 7)) | (word << ((-shift) & 7));
173 }
174
175 /**
176 * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
177 * @value: value to sign extend
178 * @index: 0 based bit index (0<=index<32) to sign bit
179 *
180 * This is safe to use for 16- and 8-bit types as well.
181 */
sign_extend32(__u32 value,int index)182 static __always_inline __s32 sign_extend32(__u32 value, int index)
183 {
184 __u8 shift = 31 - index;
185 return (__s32)(value << shift) >> shift;
186 }
187
188 /**
189 * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
190 * @value: value to sign extend
191 * @index: 0 based bit index (0<=index<64) to sign bit
192 */
sign_extend64(__u64 value,int index)193 static __always_inline __s64 sign_extend64(__u64 value, int index)
194 {
195 __u8 shift = 63 - index;
196 return (__s64)(value << shift) >> shift;
197 }
198
fls_long(unsigned long l)199 static inline unsigned int fls_long(unsigned long l)
200 {
201 if (sizeof(l) == 4)
202 return fls(l);
203 return fls64(l);
204 }
205
get_count_order(unsigned int count)206 static inline int get_count_order(unsigned int count)
207 {
208 if (count == 0)
209 return -1;
210
211 return fls(--count);
212 }
213
214 /**
215 * get_count_order_long - get order after rounding @l up to power of 2
216 * @l: parameter
217 *
218 * it is same as get_count_order() but with long type parameter
219 */
get_count_order_long(unsigned long l)220 static inline int get_count_order_long(unsigned long l)
221 {
222 if (l == 0UL)
223 return -1;
224 return (int)fls_long(--l);
225 }
226
227 /**
228 * __ffs64 - find first set bit in a 64 bit word
229 * @word: The 64 bit word
230 *
231 * On 64 bit arches this is a synonym for __ffs
232 * The result is not defined if no bits are set, so check that @word
233 * is non-zero before calling this.
234 */
__ffs64(u64 word)235 static inline unsigned int __ffs64(u64 word)
236 {
237 #if BITS_PER_LONG == 32
238 if (((u32)word) == 0UL)
239 return __ffs((u32)(word >> 32)) + 32;
240 #elif BITS_PER_LONG != 64
241 #error BITS_PER_LONG not 32 or 64
242 #endif
243 return __ffs((unsigned long)word);
244 }
245
246 /**
247 * fns - find N'th set bit in a word
248 * @word: The word to search
249 * @n: Bit to find
250 */
fns(unsigned long word,unsigned int n)251 static inline unsigned int fns(unsigned long word, unsigned int n)
252 {
253 while (word && n--)
254 word &= word - 1;
255
256 return word ? __ffs(word) : BITS_PER_LONG;
257 }
258
259 /**
260 * assign_bit - Assign value to a bit in memory
261 * @nr: the bit to set
262 * @addr: the address to start counting from
263 * @value: the value to assign
264 */
265 #define assign_bit(nr, addr, value) \
266 ((value) ? set_bit((nr), (addr)) : clear_bit((nr), (addr)))
267
268 #define __assign_bit(nr, addr, value) \
269 ((value) ? __set_bit((nr), (addr)) : __clear_bit((nr), (addr)))
270
271 /**
272 * __ptr_set_bit - Set bit in a pointer's value
273 * @nr: the bit to set
274 * @addr: the address of the pointer variable
275 *
276 * Example:
277 * void *p = foo();
278 * __ptr_set_bit(bit, &p);
279 */
280 #define __ptr_set_bit(nr, addr) \
281 ({ \
282 typecheck_pointer(*(addr)); \
283 __set_bit(nr, (unsigned long *)(addr)); \
284 })
285
286 /**
287 * __ptr_clear_bit - Clear bit in a pointer's value
288 * @nr: the bit to clear
289 * @addr: the address of the pointer variable
290 *
291 * Example:
292 * void *p = foo();
293 * __ptr_clear_bit(bit, &p);
294 */
295 #define __ptr_clear_bit(nr, addr) \
296 ({ \
297 typecheck_pointer(*(addr)); \
298 __clear_bit(nr, (unsigned long *)(addr)); \
299 })
300
301 /**
302 * __ptr_test_bit - Test bit in a pointer's value
303 * @nr: the bit to test
304 * @addr: the address of the pointer variable
305 *
306 * Example:
307 * void *p = foo();
308 * if (__ptr_test_bit(bit, &p)) {
309 * ...
310 * } else {
311 * ...
312 * }
313 */
314 #define __ptr_test_bit(nr, addr) \
315 ({ \
316 typecheck_pointer(*(addr)); \
317 test_bit(nr, (unsigned long *)(addr)); \
318 })
319
320 #ifdef __KERNEL__
321
322 #ifndef set_mask_bits
323 #define set_mask_bits(ptr, mask, bits) \
324 ({ \
325 const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \
326 typeof(*(ptr)) old__, new__; \
327 \
328 old__ = READ_ONCE(*(ptr)); \
329 do { \
330 new__ = (old__ & ~mask__) | bits__; \
331 } while (!try_cmpxchg(ptr, &old__, new__)); \
332 \
333 old__; \
334 })
335 #endif
336
337 #ifndef bit_clear_unless
338 #define bit_clear_unless(ptr, clear, test) \
339 ({ \
340 const typeof(*(ptr)) clear__ = (clear), test__ = (test);\
341 typeof(*(ptr)) old__, new__; \
342 \
343 old__ = READ_ONCE(*(ptr)); \
344 do { \
345 if (old__ & test__) \
346 break; \
347 new__ = old__ & ~clear__; \
348 } while (!try_cmpxchg(ptr, &old__, new__)); \
349 \
350 !(old__ & test__); \
351 })
352 #endif
353
354 #endif /* __KERNEL__ */
355 #endif
356