xref: /linux/arch/s390/include/asm/bitops.h (revision 906fd46a65383cd639e5eec72a047efc33045d86) 
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  *    Copyright IBM Corp. 1999,2013
4  *
5  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
6  *
7  * The description below was taken in large parts from the powerpc
8  * bitops header file:
9  * Within a word, bits are numbered LSB first.  Lot's of places make
10  * this assumption by directly testing bits with (val & (1<<nr)).
11  * This can cause confusion for large (> 1 word) bitmaps on a
12  * big-endian system because, unlike little endian, the number of each
13  * bit depends on the word size.
14  *
15  * The bitop functions are defined to work on unsigned longs, so the bits
16  * end up numbered:
17  *   |63..............0|127............64|191...........128|255...........192|
18  *
19  * We also have special functions which work with an MSB0 encoding.
20  * The bits are numbered:
21  *   |0..............63|64............127|128...........191|192...........255|
22  *
23  * The main difference is that bit 0-63 in the bit number field needs to be
24  * reversed compared to the LSB0 encoded bit fields. This can be achieved by
25  * XOR with 0x3f.
26  *
27  */
28 
29 #ifndef _S390_BITOPS_H
30 #define _S390_BITOPS_H
31 
32 #ifndef _LINUX_BITOPS_H
33 #error only <linux/bitops.h> can be included directly
34 #endif
35 
36 #include <linux/typecheck.h>
37 #include <linux/compiler.h>
38 #include <linux/types.h>
39 #include <asm/atomic_ops.h>
40 #include <asm/barrier.h>
41 
42 #define __BITOPS_WORDS(bits) (((bits) + BITS_PER_LONG - 1) / BITS_PER_LONG)
43 
44 static inline unsigned long *
45 __bitops_word(unsigned long nr, const volatile unsigned long *ptr)
46 {
47 	unsigned long addr;
48 
49 	addr = (unsigned long)ptr + ((nr ^ (nr & (BITS_PER_LONG - 1))) >> 3);
50 	return (unsigned long *)addr;
51 }
52 
53 static inline unsigned long __bitops_mask(unsigned long nr)
54 {
55 	return 1UL << (nr & (BITS_PER_LONG - 1));
56 }
57 
58 static __always_inline void arch_set_bit(unsigned long nr, volatile unsigned long *ptr)
59 {
60 	unsigned long *addr = __bitops_word(nr, ptr);
61 	unsigned long mask = __bitops_mask(nr);
62 
63 	__atomic64_or(mask, (long *)addr);
64 }
65 
66 static __always_inline void arch_clear_bit(unsigned long nr, volatile unsigned long *ptr)
67 {
68 	unsigned long *addr = __bitops_word(nr, ptr);
69 	unsigned long mask = __bitops_mask(nr);
70 
71 	__atomic64_and(~mask, (long *)addr);
72 }
73 
74 static __always_inline void arch_change_bit(unsigned long nr,
75 					    volatile unsigned long *ptr)
76 {
77 	unsigned long *addr = __bitops_word(nr, ptr);
78 	unsigned long mask = __bitops_mask(nr);
79 
80 	__atomic64_xor(mask, (long *)addr);
81 }
82 
83 static inline bool arch_test_and_set_bit(unsigned long nr,
84 					 volatile unsigned long *ptr)
85 {
86 	unsigned long *addr = __bitops_word(nr, ptr);
87 	unsigned long mask = __bitops_mask(nr);
88 	unsigned long old;
89 
90 	old = __atomic64_or_barrier(mask, (long *)addr);
91 	return old & mask;
92 }
93 
94 static inline bool arch_test_and_clear_bit(unsigned long nr,
95 					   volatile unsigned long *ptr)
96 {
97 	unsigned long *addr = __bitops_word(nr, ptr);
98 	unsigned long mask = __bitops_mask(nr);
99 	unsigned long old;
100 
101 	old = __atomic64_and_barrier(~mask, (long *)addr);
102 	return old & mask;
103 }
104 
105 static inline bool arch_test_and_change_bit(unsigned long nr,
106 					    volatile unsigned long *ptr)
107 {
108 	unsigned long *addr = __bitops_word(nr, ptr);
109 	unsigned long mask = __bitops_mask(nr);
110 	unsigned long old;
111 
112 	old = __atomic64_xor_barrier(mask, (long *)addr);
113 	return old & mask;
114 }
115 
116 static __always_inline void
117 arch___set_bit(unsigned long nr, volatile unsigned long *addr)
118 {
119 	unsigned long *p = __bitops_word(nr, addr);
120 	unsigned long mask = __bitops_mask(nr);
121 
122 	*p |= mask;
123 }
124 
125 static __always_inline void
126 arch___clear_bit(unsigned long nr, volatile unsigned long *addr)
127 {
128 	unsigned long *p = __bitops_word(nr, addr);
129 	unsigned long mask = __bitops_mask(nr);
130 
131 	*p &= ~mask;
132 }
133 
134 static __always_inline void
135 arch___change_bit(unsigned long nr, volatile unsigned long *addr)
136 {
137 	unsigned long *p = __bitops_word(nr, addr);
138 	unsigned long mask = __bitops_mask(nr);
139 
140 	*p ^= mask;
141 }
142 
143 static __always_inline bool
144 arch___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
145 {
146 	unsigned long *p = __bitops_word(nr, addr);
147 	unsigned long mask = __bitops_mask(nr);
148 	unsigned long old;
149 
150 	old = *p;
151 	*p |= mask;
152 	return old & mask;
153 }
154 
155 static __always_inline bool
156 arch___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
157 {
158 	unsigned long *p = __bitops_word(nr, addr);
159 	unsigned long mask = __bitops_mask(nr);
160 	unsigned long old;
161 
162 	old = *p;
163 	*p &= ~mask;
164 	return old & mask;
165 }
166 
167 static __always_inline bool
168 arch___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
169 {
170 	unsigned long *p = __bitops_word(nr, addr);
171 	unsigned long mask = __bitops_mask(nr);
172 	unsigned long old;
173 
174 	old = *p;
175 	*p ^= mask;
176 	return old & mask;
177 }
178 
179 #define arch_test_bit generic_test_bit
180 #define arch_test_bit_acquire generic_test_bit_acquire
181 
182 static inline bool arch_test_and_set_bit_lock(unsigned long nr,
183 					      volatile unsigned long *ptr)
184 {
185 	if (arch_test_bit(nr, ptr))
186 		return true;
187 	return arch_test_and_set_bit(nr, ptr);
188 }
189 
190 static inline void arch_clear_bit_unlock(unsigned long nr,
191 					 volatile unsigned long *ptr)
192 {
193 	smp_mb__before_atomic();
194 	arch_clear_bit(nr, ptr);
195 }
196 
197 static inline void arch___clear_bit_unlock(unsigned long nr,
198 					   volatile unsigned long *ptr)
199 {
200 	smp_mb();
201 	arch___clear_bit(nr, ptr);
202 }
203 
204 static inline bool arch_xor_unlock_is_negative_byte(unsigned long mask,
205 		volatile unsigned long *ptr)
206 {
207 	unsigned long old;
208 
209 	old = __atomic64_xor_barrier(mask, (long *)ptr);
210 	return old & BIT(7);
211 }
212 #define arch_xor_unlock_is_negative_byte arch_xor_unlock_is_negative_byte
213 
214 #include <asm-generic/bitops/instrumented-atomic.h>
215 #include <asm-generic/bitops/instrumented-non-atomic.h>
216 #include <asm-generic/bitops/instrumented-lock.h>
217 
218 /*
219  * Functions which use MSB0 bit numbering.
220  * The bits are numbered:
221  *   |0..............63|64............127|128...........191|192...........255|
222  */
223 unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size);
224 unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size,
225 				unsigned long offset);
226 
227 #define for_each_set_bit_inv(bit, addr, size)				\
228 	for ((bit) = find_first_bit_inv((addr), (size));		\
229 	     (bit) < (size);						\
230 	     (bit) = find_next_bit_inv((addr), (size), (bit) + 1))
231 
232 static inline void set_bit_inv(unsigned long nr, volatile unsigned long *ptr)
233 {
234 	return set_bit(nr ^ (BITS_PER_LONG - 1), ptr);
235 }
236 
237 static inline void clear_bit_inv(unsigned long nr, volatile unsigned long *ptr)
238 {
239 	return clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
240 }
241 
242 static inline bool test_and_clear_bit_inv(unsigned long nr,
243 					  volatile unsigned long *ptr)
244 {
245 	return test_and_clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
246 }
247 
248 static inline void __set_bit_inv(unsigned long nr, volatile unsigned long *ptr)
249 {
250 	return __set_bit(nr ^ (BITS_PER_LONG - 1), ptr);
251 }
252 
253 static inline void __clear_bit_inv(unsigned long nr, volatile unsigned long *ptr)
254 {
255 	return __clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
256 }
257 
258 static inline bool test_bit_inv(unsigned long nr,
259 				const volatile unsigned long *ptr)
260 {
261 	return test_bit(nr ^ (BITS_PER_LONG - 1), ptr);
262 }
263 
264 /**
265  * __flogr - find leftmost one
266  * @word - The word to search
267  *
268  * Returns the bit number of the most significant bit set,
269  * where the most significant bit has bit number 0.
270  * If no bit is set this function returns 64.
271  */
272 static inline unsigned char __flogr(unsigned long word)
273 {
274 	if (__builtin_constant_p(word)) {
275 		unsigned long bit = 0;
276 
277 		if (!word)
278 			return 64;
279 		if (!(word & 0xffffffff00000000UL)) {
280 			word <<= 32;
281 			bit += 32;
282 		}
283 		if (!(word & 0xffff000000000000UL)) {
284 			word <<= 16;
285 			bit += 16;
286 		}
287 		if (!(word & 0xff00000000000000UL)) {
288 			word <<= 8;
289 			bit += 8;
290 		}
291 		if (!(word & 0xf000000000000000UL)) {
292 			word <<= 4;
293 			bit += 4;
294 		}
295 		if (!(word & 0xc000000000000000UL)) {
296 			word <<= 2;
297 			bit += 2;
298 		}
299 		if (!(word & 0x8000000000000000UL)) {
300 			word <<= 1;
301 			bit += 1;
302 		}
303 		return bit;
304 	} else {
305 		union register_pair rp;
306 
307 		rp.even = word;
308 		asm volatile(
309 			"       flogr   %[rp],%[rp]\n"
310 			: [rp] "+d" (rp.pair) : : "cc");
311 		return rp.even;
312 	}
313 }
314 
315 /**
316  * __ffs - find first bit in word.
317  * @word: The word to search
318  *
319  * Undefined if no bit exists, so code should check against 0 first.
320  */
321 static inline unsigned long __ffs(unsigned long word)
322 {
323 	return __flogr(-word & word) ^ (BITS_PER_LONG - 1);
324 }
325 
326 /**
327  * ffs - find first bit set
328  * @word: the word to search
329  *
330  * This is defined the same way as the libc and
331  * compiler builtin ffs routines (man ffs).
332  */
333 static inline int ffs(int word)
334 {
335 	unsigned long mask = 2 * BITS_PER_LONG - 1;
336 	unsigned int val = (unsigned int)word;
337 
338 	return (1 + (__flogr(-val & val) ^ (BITS_PER_LONG - 1))) & mask;
339 }
340 
341 /**
342  * __fls - find last (most-significant) set bit in a long word
343  * @word: the word to search
344  *
345  * Undefined if no set bit exists, so code should check against 0 first.
346  */
347 static inline unsigned long __fls(unsigned long word)
348 {
349 	return __flogr(word) ^ (BITS_PER_LONG - 1);
350 }
351 
352 /**
353  * fls64 - find last set bit in a 64-bit word
354  * @word: the word to search
355  *
356  * This is defined in a similar way as the libc and compiler builtin
357  * ffsll, but returns the position of the most significant set bit.
358  *
359  * fls64(value) returns 0 if value is 0 or the position of the last
360  * set bit if value is nonzero. The last (most significant) bit is
361  * at position 64.
362  */
363 static inline int fls64(unsigned long word)
364 {
365 	unsigned long mask = 2 * BITS_PER_LONG - 1;
366 
367 	return (1 + (__flogr(word) ^ (BITS_PER_LONG - 1))) & mask;
368 }
369 
370 /**
371  * fls - find last (most-significant) bit set
372  * @word: the word to search
373  *
374  * This is defined the same way as ffs.
375  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
376  */
377 static inline int fls(unsigned int word)
378 {
379 	return fls64(word);
380 }
381 
382 #include <asm-generic/bitops/ffz.h>
383 #include <asm-generic/bitops/hweight.h>
384 #include <asm-generic/bitops/sched.h>
385 #include <asm-generic/bitops/le.h>
386 #include <asm-generic/bitops/ext2-atomic-setbit.h>
387 
388 #endif /* _S390_BITOPS_H */
389