Line data Source code
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 : /* Set bits in the first 'n' bytes when loaded from memory */
12 : #ifdef __LITTLE_ENDIAN
13 : # define aligned_byte_mask(n) ((1UL << 8*(n))-1)
14 : #else
15 : # define aligned_byte_mask(n) (~0xffUL << (BITS_PER_LONG - 8 - 8*(n)))
16 : #endif
17 :
18 : #define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
19 : #define BITS_TO_LONGS(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(long))
20 : #define BITS_TO_U64(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u64))
21 : #define BITS_TO_U32(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u32))
22 : #define BITS_TO_BYTES(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(char))
23 :
24 : extern unsigned int __sw_hweight8(unsigned int w);
25 : extern unsigned int __sw_hweight16(unsigned int w);
26 : extern unsigned int __sw_hweight32(unsigned int w);
27 : extern unsigned long __sw_hweight64(__u64 w);
28 :
29 : /*
30 : * Defined here because those may be needed by architecture-specific static
31 : * inlines.
32 : */
33 :
34 : #include <asm-generic/bitops/generic-non-atomic.h>
35 :
36 : /*
37 : * Many architecture-specific non-atomic bitops contain inline asm code and due
38 : * to that the compiler can't optimize them to compile-time expressions or
39 : * constants. In contrary, generic_*() helpers are defined in pure C and
40 : * compilers optimize them just well.
41 : * Therefore, to make `unsigned long foo = 0; __set_bit(BAR, &foo)` effectively
42 : * equal to `unsigned long foo = BIT(BAR)`, pick the generic C alternative when
43 : * the arguments can be resolved at compile time. That expression itself is a
44 : * constant and doesn't bring any functional changes to the rest of cases.
45 : * The casts to `uintptr_t` are needed to mitigate `-Waddress` warnings when
46 : * passing a bitmap from .bss or .data (-> `!!addr` is always true).
47 : */
48 : #define bitop(op, nr, addr) \
49 : ((__builtin_constant_p(nr) && \
50 : __builtin_constant_p((uintptr_t)(addr) != (uintptr_t)NULL) && \
51 : (uintptr_t)(addr) != (uintptr_t)NULL && \
52 : __builtin_constant_p(*(const unsigned long *)(addr))) ? \
53 : const##op(nr, addr) : op(nr, addr))
54 :
55 : #define __set_bit(nr, addr) bitop(___set_bit, nr, addr)
56 : #define __clear_bit(nr, addr) bitop(___clear_bit, nr, addr)
57 : #define __change_bit(nr, addr) bitop(___change_bit, nr, addr)
58 : #define __test_and_set_bit(nr, addr) bitop(___test_and_set_bit, nr, addr)
59 : #define __test_and_clear_bit(nr, addr) bitop(___test_and_clear_bit, nr, addr)
60 : #define __test_and_change_bit(nr, addr) bitop(___test_and_change_bit, nr, addr)
61 : #define test_bit(nr, addr) bitop(_test_bit, nr, addr)
62 : #define test_bit_acquire(nr, addr) bitop(_test_bit_acquire, nr, addr)
63 :
64 : /*
65 : * Include this here because some architectures need generic_ffs/fls in
66 : * scope
67 : */
68 : #include <asm/bitops.h>
69 :
70 : /* Check that the bitops prototypes are sane */
71 : #define __check_bitop_pr(name) \
72 : static_assert(__same_type(arch_##name, generic_##name) && \
73 : __same_type(const_##name, generic_##name) && \
74 : __same_type(_##name, generic_##name))
75 :
76 : __check_bitop_pr(__set_bit);
77 : __check_bitop_pr(__clear_bit);
78 : __check_bitop_pr(__change_bit);
79 : __check_bitop_pr(__test_and_set_bit);
80 : __check_bitop_pr(__test_and_clear_bit);
81 : __check_bitop_pr(__test_and_change_bit);
82 : __check_bitop_pr(test_bit);
83 :
84 : #undef __check_bitop_pr
85 :
86 : static inline int get_bitmask_order(unsigned int count)
87 : {
88 : int order;
89 :
90 : order = fls(count);
91 : return order; /* We could be slightly more clever with -1 here... */
92 : }
93 :
94 : static __always_inline unsigned long hweight_long(unsigned long w)
95 : {
96 4 : return sizeof(w) == 4 ? hweight32(w) : hweight64((__u64)w);
97 : }
98 :
99 : /**
100 : * rol64 - rotate a 64-bit value left
101 : * @word: value to rotate
102 : * @shift: bits to roll
103 : */
104 : static inline __u64 rol64(__u64 word, unsigned int shift)
105 : {
106 62 : return (word << (shift & 63)) | (word >> ((-shift) & 63));
107 : }
108 :
109 : /**
110 : * ror64 - rotate a 64-bit value right
111 : * @word: value to rotate
112 : * @shift: bits to roll
113 : */
114 : static inline __u64 ror64(__u64 word, unsigned int shift)
115 : {
116 : return (word >> (shift & 63)) | (word << ((-shift) & 63));
117 : }
118 :
119 : /**
120 : * rol32 - rotate a 32-bit value left
121 : * @word: value to rotate
122 : * @shift: bits to roll
123 : */
124 : static inline __u32 rol32(__u32 word, unsigned int shift)
125 : {
126 64042 : return (word << (shift & 31)) | (word >> ((-shift) & 31));
127 : }
128 :
129 : /**
130 : * ror32 - rotate a 32-bit value right
131 : * @word: value to rotate
132 : * @shift: bits to roll
133 : */
134 : static inline __u32 ror32(__u32 word, unsigned int shift)
135 : {
136 765440 : return (word >> (shift & 31)) | (word << ((-shift) & 31));
137 : }
138 :
139 : /**
140 : * rol16 - rotate a 16-bit value left
141 : * @word: value to rotate
142 : * @shift: bits to roll
143 : */
144 : static inline __u16 rol16(__u16 word, unsigned int shift)
145 : {
146 : return (word << (shift & 15)) | (word >> ((-shift) & 15));
147 : }
148 :
149 : /**
150 : * ror16 - rotate a 16-bit value right
151 : * @word: value to rotate
152 : * @shift: bits to roll
153 : */
154 : static inline __u16 ror16(__u16 word, unsigned int shift)
155 : {
156 : return (word >> (shift & 15)) | (word << ((-shift) & 15));
157 : }
158 :
159 : /**
160 : * rol8 - rotate an 8-bit value left
161 : * @word: value to rotate
162 : * @shift: bits to roll
163 : */
164 : static inline __u8 rol8(__u8 word, unsigned int shift)
165 : {
166 : return (word << (shift & 7)) | (word >> ((-shift) & 7));
167 : }
168 :
169 : /**
170 : * ror8 - rotate an 8-bit value right
171 : * @word: value to rotate
172 : * @shift: bits to roll
173 : */
174 : static inline __u8 ror8(__u8 word, unsigned int shift)
175 : {
176 : return (word >> (shift & 7)) | (word << ((-shift) & 7));
177 : }
178 :
179 : /**
180 : * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
181 : * @value: value to sign extend
182 : * @index: 0 based bit index (0<=index<32) to sign bit
183 : *
184 : * This is safe to use for 16- and 8-bit types as well.
185 : */
186 : static __always_inline __s32 sign_extend32(__u32 value, int index)
187 : {
188 0 : __u8 shift = 31 - index;
189 0 : return (__s32)(value << shift) >> shift;
190 : }
191 :
192 : /**
193 : * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
194 : * @value: value to sign extend
195 : * @index: 0 based bit index (0<=index<64) to sign bit
196 : */
197 : static __always_inline __s64 sign_extend64(__u64 value, int index)
198 : {
199 : __u8 shift = 63 - index;
200 : return (__s64)(value << shift) >> shift;
201 : }
202 :
203 : static inline unsigned fls_long(unsigned long l)
204 : {
205 : if (sizeof(l) == 4)
206 : return fls(l);
207 10 : return fls64(l);
208 : }
209 :
210 : static inline int get_count_order(unsigned int count)
211 : {
212 : if (count == 0)
213 : return -1;
214 :
215 : return fls(--count);
216 : }
217 :
218 : /**
219 : * get_count_order_long - get order after rounding @l up to power of 2
220 : * @l: parameter
221 : *
222 : * it is same as get_count_order() but with long type parameter
223 : */
224 : static inline int get_count_order_long(unsigned long l)
225 : {
226 0 : if (l == 0UL)
227 : return -1;
228 0 : return (int)fls_long(--l);
229 : }
230 :
231 : /**
232 : * __ffs64 - find first set bit in a 64 bit word
233 : * @word: The 64 bit word
234 : *
235 : * On 64 bit arches this is a synonym for __ffs
236 : * The result is not defined if no bits are set, so check that @word
237 : * is non-zero before calling this.
238 : */
239 : static inline unsigned long __ffs64(u64 word)
240 : {
241 : #if BITS_PER_LONG == 32
242 : if (((u32)word) == 0UL)
243 : return __ffs((u32)(word >> 32)) + 32;
244 : #elif BITS_PER_LONG != 64
245 : #error BITS_PER_LONG not 32 or 64
246 : #endif
247 0 : return __ffs((unsigned long)word);
248 : }
249 :
250 : /**
251 : * fns - find N'th set bit in a word
252 : * @word: The word to search
253 : * @n: Bit to find
254 : */
255 0 : static inline unsigned long fns(unsigned long word, unsigned int n)
256 : {
257 : unsigned int bit;
258 :
259 0 : while (word) {
260 0 : bit = __ffs(word);
261 0 : if (n-- == 0)
262 0 : return bit;
263 0 : __clear_bit(bit, &word);
264 : }
265 :
266 : return BITS_PER_LONG;
267 : }
268 :
269 : /**
270 : * assign_bit - Assign value to a bit in memory
271 : * @nr: the bit to set
272 : * @addr: the address to start counting from
273 : * @value: the value to assign
274 : */
275 : static __always_inline void assign_bit(long nr, volatile unsigned long *addr,
276 : bool value)
277 : {
278 : if (value)
279 : set_bit(nr, addr);
280 : else
281 : clear_bit(nr, addr);
282 : }
283 :
284 : static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
285 : bool value)
286 : {
287 : if (value)
288 : __set_bit(nr, addr);
289 : else
290 : __clear_bit(nr, addr);
291 : }
292 :
293 : /**
294 : * __ptr_set_bit - Set bit in a pointer's value
295 : * @nr: the bit to set
296 : * @addr: the address of the pointer variable
297 : *
298 : * Example:
299 : * void *p = foo();
300 : * __ptr_set_bit(bit, &p);
301 : */
302 : #define __ptr_set_bit(nr, addr) \
303 : ({ \
304 : typecheck_pointer(*(addr)); \
305 : __set_bit(nr, (unsigned long *)(addr)); \
306 : })
307 :
308 : /**
309 : * __ptr_clear_bit - Clear bit in a pointer's value
310 : * @nr: the bit to clear
311 : * @addr: the address of the pointer variable
312 : *
313 : * Example:
314 : * void *p = foo();
315 : * __ptr_clear_bit(bit, &p);
316 : */
317 : #define __ptr_clear_bit(nr, addr) \
318 : ({ \
319 : typecheck_pointer(*(addr)); \
320 : __clear_bit(nr, (unsigned long *)(addr)); \
321 : })
322 :
323 : /**
324 : * __ptr_test_bit - Test bit in a pointer's value
325 : * @nr: the bit to test
326 : * @addr: the address of the pointer variable
327 : *
328 : * Example:
329 : * void *p = foo();
330 : * if (__ptr_test_bit(bit, &p)) {
331 : * ...
332 : * } else {
333 : * ...
334 : * }
335 : */
336 : #define __ptr_test_bit(nr, addr) \
337 : ({ \
338 : typecheck_pointer(*(addr)); \
339 : test_bit(nr, (unsigned long *)(addr)); \
340 : })
341 :
342 : #ifdef __KERNEL__
343 :
344 : #ifndef set_mask_bits
345 : #define set_mask_bits(ptr, mask, bits) \
346 : ({ \
347 : const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \
348 : typeof(*(ptr)) old__, new__; \
349 : \
350 : old__ = READ_ONCE(*(ptr)); \
351 : do { \
352 : new__ = (old__ & ~mask__) | bits__; \
353 : } while (!try_cmpxchg(ptr, &old__, new__)); \
354 : \
355 : old__; \
356 : })
357 : #endif
358 :
359 : #ifndef bit_clear_unless
360 : #define bit_clear_unless(ptr, clear, test) \
361 : ({ \
362 : const typeof(*(ptr)) clear__ = (clear), test__ = (test);\
363 : typeof(*(ptr)) old__, new__; \
364 : \
365 : old__ = READ_ONCE(*(ptr)); \
366 : do { \
367 : if (old__ & test__) \
368 : break; \
369 : new__ = old__ & ~clear__; \
370 : } while (!try_cmpxchg(ptr, &old__, new__)); \
371 : \
372 : !(old__ & test__); \
373 : })
374 : #endif
375 :
376 : #endif /* __KERNEL__ */
377 : #endif
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