bitops.h

  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/asm.h>
 40
 41#define arch___set_bit			generic___set_bit
 42#define arch___clear_bit		generic___clear_bit
 43#define arch___change_bit		generic___change_bit
 44#define arch___test_and_set_bit		generic___test_and_set_bit
 45#define arch___test_and_clear_bit	generic___test_and_clear_bit
 46#define arch___test_and_change_bit	generic___test_and_change_bit
 47#define arch_test_bit_acquire		generic_test_bit_acquire
 48
 49static __always_inline bool arch_test_bit(unsigned long nr, const volatile unsigned long *ptr)
 50{
 51#ifdef __HAVE_ASM_FLAG_OUTPUTS__
 52	const volatile unsigned char *addr;
 53	unsigned long mask;
 54	int cc;
 55
 56	/*
 57	 * With CONFIG_PROFILE_ALL_BRANCHES enabled gcc fails to
 58	 * handle __builtin_constant_p() in some cases.
 59	 */
 60	if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && __builtin_constant_p(nr)) {
 61		addr = (const volatile unsigned char *)ptr;
 62		addr += (nr ^ (BITS_PER_LONG - BITS_PER_BYTE)) / BITS_PER_BYTE;
 63		mask = 1UL << (nr & (BITS_PER_BYTE - 1));
 64		asm volatile(
 65			"	tm	%[addr],%[mask]"
 66			: "=@cc" (cc)
 67			: [addr] "Q" (*addr), [mask] "I" (mask)
 68			);
 69		return cc == 3;
 70	}
 71#endif
 72	return generic_test_bit(nr, ptr);
 73}
 74
 75#include <asm-generic/bitops/atomic.h>
 76#include <asm-generic/bitops/non-instrumented-non-atomic.h>
 77#include <asm-generic/bitops/lock.h>
 78
 79/*
 80 * Functions which use MSB0 bit numbering.
 81 * The bits are numbered:
 82 *   |0..............63|64............127|128...........191|192...........255|
 83 */
 84unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size);
 85unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size,
 86				unsigned long offset);
 87
 88#define for_each_set_bit_inv(bit, addr, size)				\
 89	for ((bit) = find_first_bit_inv((addr), (size));		\
 90	     (bit) < (size);						\
 91	     (bit) = find_next_bit_inv((addr), (size), (bit) + 1))
 92
 93static inline void set_bit_inv(unsigned long nr, volatile unsigned long *ptr)
 94{
 95	return set_bit(nr ^ (BITS_PER_LONG - 1), ptr);
 96}
 97
 98static inline void clear_bit_inv(unsigned long nr, volatile unsigned long *ptr)
 99{
100	return clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
101}
102
103static inline bool test_and_clear_bit_inv(unsigned long nr,
104					  volatile unsigned long *ptr)
105{
106	return test_and_clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
107}
108
109static inline void __set_bit_inv(unsigned long nr, volatile unsigned long *ptr)
110{
111	return __set_bit(nr ^ (BITS_PER_LONG - 1), ptr);
112}
113
114static inline void __clear_bit_inv(unsigned long nr, volatile unsigned long *ptr)
115{
116	return __clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
117}
118
119static inline bool test_bit_inv(unsigned long nr,
120				const volatile unsigned long *ptr)
121{
122	return test_bit(nr ^ (BITS_PER_LONG - 1), ptr);
123}
124
125#ifndef CONFIG_CC_HAS_BUILTIN_FFS
126
127/**
128 * __flogr - find leftmost one
129 * @word - The word to search
130 *
131 * Returns the bit number of the most significant bit set,
132 * where the most significant bit has bit number 0.
133 * If no bit is set this function returns 64.
134 */
135static __always_inline __attribute_const__ unsigned long __flogr(unsigned long word)
136{
137	unsigned long bit;
138
139	if (__builtin_constant_p(word)) {
140		bit = 0;
141		if (!word)
142			return 64;
143		if (!(word & 0xffffffff00000000UL)) {
144			word <<= 32;
145			bit += 32;
146		}
147		if (!(word & 0xffff000000000000UL)) {
148			word <<= 16;
149			bit += 16;
150		}
151		if (!(word & 0xff00000000000000UL)) {
152			word <<= 8;
153			bit += 8;
154		}
155		if (!(word & 0xf000000000000000UL)) {
156			word <<= 4;
157			bit += 4;
158		}
159		if (!(word & 0xc000000000000000UL)) {
160			word <<= 2;
161			bit += 2;
162		}
163		if (!(word & 0x8000000000000000UL)) {
164			word <<= 1;
165			bit += 1;
166		}
167		return bit;
168	} else {
169		union register_pair rp __uninitialized;
170
171		rp.even = word;
172		asm("flogr	%[rp],%[rp]"
173		    : [rp] "+d" (rp.pair) : : "cc");
174		bit = rp.even;
175		/*
176		 * The result of the flogr instruction is a value in the range
177		 * of 0..64. Let the compiler know that the AND operation can
178		 * be optimized away.
179		 */
180		__assume(bit <= 64);
181		return bit & 127;
182	}
183}
184
185/**
186 * ffs - find first bit set
187 * @word: the word to search
188 *
189 * This is defined the same way as the libc and
190 * compiler builtin ffs routines (man ffs).
191 */
192static __always_inline __flatten __attribute_const__ int ffs(int word)
193{
194	unsigned int val = (unsigned int)word;
195
196	return BITS_PER_LONG - __flogr(-val & val);
197}
198
199#else /* CONFIG_CC_HAS_BUILTIN_FFS */
200
201#include <asm-generic/bitops/builtin-ffs.h>
202
203#endif /* CONFIG_CC_HAS_BUILTIN_FFS */
204
205#include <asm-generic/bitops/builtin-__ffs.h>
206#include <asm-generic/bitops/ffz.h>
207#include <asm-generic/bitops/builtin-__fls.h>
208#include <asm-generic/bitops/builtin-fls.h>
209#include <asm-generic/bitops/fls64.h>
210#include <asm/arch_hweight.h>
211#include <asm-generic/bitops/const_hweight.h>
212#include <asm-generic/bitops/sched.h>
213#include <asm-generic/bitops/le.h>
214#include <asm-generic/bitops/ext2-atomic-setbit.h>
215
216#endif /* _S390_BITOPS_H */