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Inspired by the s390 arch_test_and_clear_bit(), this will surely be more efficient than the generic one defined in filemap.c. Link: https://lkml.kernel.org/r/20231004165317.1061855-14-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
389 lines
9.7 KiB
C
389 lines
9.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright IBM Corp. 1999,2013
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*
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
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*
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* The description below was taken in large parts from the powerpc
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* bitops header file:
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* Within a word, bits are numbered LSB first. Lot's of places make
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* this assumption by directly testing bits with (val & (1<<nr)).
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* This can cause confusion for large (> 1 word) bitmaps on a
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* big-endian system because, unlike little endian, the number of each
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* bit depends on the word size.
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*
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* The bitop functions are defined to work on unsigned longs, so the bits
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* end up numbered:
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* |63..............0|127............64|191...........128|255...........192|
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*
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* We also have special functions which work with an MSB0 encoding.
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* The bits are numbered:
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* |0..............63|64............127|128...........191|192...........255|
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*
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* The main difference is that bit 0-63 in the bit number field needs to be
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* reversed compared to the LSB0 encoded bit fields. This can be achieved by
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* XOR with 0x3f.
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*
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*/
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#ifndef _S390_BITOPS_H
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#define _S390_BITOPS_H
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#ifndef _LINUX_BITOPS_H
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#error only <linux/bitops.h> can be included directly
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#endif
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#include <linux/typecheck.h>
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/atomic_ops.h>
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#include <asm/barrier.h>
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#define __BITOPS_WORDS(bits) (((bits) + BITS_PER_LONG - 1) / BITS_PER_LONG)
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static inline unsigned long *
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__bitops_word(unsigned long nr, const volatile unsigned long *ptr)
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{
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unsigned long addr;
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addr = (unsigned long)ptr + ((nr ^ (nr & (BITS_PER_LONG - 1))) >> 3);
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return (unsigned long *)addr;
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}
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static inline unsigned long __bitops_mask(unsigned long nr)
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{
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return 1UL << (nr & (BITS_PER_LONG - 1));
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}
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static __always_inline void arch_set_bit(unsigned long nr, volatile unsigned long *ptr)
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{
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unsigned long *addr = __bitops_word(nr, ptr);
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unsigned long mask = __bitops_mask(nr);
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__atomic64_or(mask, (long *)addr);
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}
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static __always_inline void arch_clear_bit(unsigned long nr, volatile unsigned long *ptr)
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{
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unsigned long *addr = __bitops_word(nr, ptr);
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unsigned long mask = __bitops_mask(nr);
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__atomic64_and(~mask, (long *)addr);
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}
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static __always_inline void arch_change_bit(unsigned long nr,
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volatile unsigned long *ptr)
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{
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unsigned long *addr = __bitops_word(nr, ptr);
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unsigned long mask = __bitops_mask(nr);
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__atomic64_xor(mask, (long *)addr);
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}
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static inline bool arch_test_and_set_bit(unsigned long nr,
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volatile unsigned long *ptr)
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{
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unsigned long *addr = __bitops_word(nr, ptr);
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unsigned long mask = __bitops_mask(nr);
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unsigned long old;
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old = __atomic64_or_barrier(mask, (long *)addr);
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return old & mask;
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}
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static inline bool arch_test_and_clear_bit(unsigned long nr,
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volatile unsigned long *ptr)
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{
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unsigned long *addr = __bitops_word(nr, ptr);
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unsigned long mask = __bitops_mask(nr);
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unsigned long old;
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old = __atomic64_and_barrier(~mask, (long *)addr);
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return old & mask;
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}
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static inline bool arch_test_and_change_bit(unsigned long nr,
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volatile unsigned long *ptr)
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{
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unsigned long *addr = __bitops_word(nr, ptr);
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unsigned long mask = __bitops_mask(nr);
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unsigned long old;
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old = __atomic64_xor_barrier(mask, (long *)addr);
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return old & mask;
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}
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static __always_inline void
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arch___set_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *p = __bitops_word(nr, addr);
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unsigned long mask = __bitops_mask(nr);
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*p |= mask;
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}
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static __always_inline void
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arch___clear_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *p = __bitops_word(nr, addr);
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unsigned long mask = __bitops_mask(nr);
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*p &= ~mask;
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}
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static __always_inline void
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arch___change_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *p = __bitops_word(nr, addr);
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unsigned long mask = __bitops_mask(nr);
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*p ^= mask;
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}
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static __always_inline bool
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arch___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *p = __bitops_word(nr, addr);
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unsigned long mask = __bitops_mask(nr);
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unsigned long old;
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old = *p;
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*p |= mask;
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return old & mask;
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}
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static __always_inline bool
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arch___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *p = __bitops_word(nr, addr);
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unsigned long mask = __bitops_mask(nr);
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unsigned long old;
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old = *p;
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*p &= ~mask;
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return old & mask;
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}
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static __always_inline bool
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arch___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *p = __bitops_word(nr, addr);
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unsigned long mask = __bitops_mask(nr);
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unsigned long old;
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old = *p;
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*p ^= mask;
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return old & mask;
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}
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#define arch_test_bit generic_test_bit
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#define arch_test_bit_acquire generic_test_bit_acquire
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static inline bool arch_test_and_set_bit_lock(unsigned long nr,
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volatile unsigned long *ptr)
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{
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if (arch_test_bit(nr, ptr))
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return true;
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return arch_test_and_set_bit(nr, ptr);
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}
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static inline void arch_clear_bit_unlock(unsigned long nr,
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volatile unsigned long *ptr)
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{
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smp_mb__before_atomic();
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arch_clear_bit(nr, ptr);
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}
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static inline void arch___clear_bit_unlock(unsigned long nr,
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volatile unsigned long *ptr)
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{
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smp_mb();
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arch___clear_bit(nr, ptr);
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}
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static inline bool arch_xor_unlock_is_negative_byte(unsigned long mask,
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volatile unsigned long *ptr)
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{
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unsigned long old;
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old = __atomic64_xor_barrier(mask, (long *)ptr);
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return old & BIT(7);
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}
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#define arch_xor_unlock_is_negative_byte arch_xor_unlock_is_negative_byte
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#include <asm-generic/bitops/instrumented-atomic.h>
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#include <asm-generic/bitops/instrumented-non-atomic.h>
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#include <asm-generic/bitops/instrumented-lock.h>
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/*
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* Functions which use MSB0 bit numbering.
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* The bits are numbered:
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* |0..............63|64............127|128...........191|192...........255|
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*/
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unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size);
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unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size,
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unsigned long offset);
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#define for_each_set_bit_inv(bit, addr, size) \
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for ((bit) = find_first_bit_inv((addr), (size)); \
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(bit) < (size); \
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(bit) = find_next_bit_inv((addr), (size), (bit) + 1))
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static inline void set_bit_inv(unsigned long nr, volatile unsigned long *ptr)
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{
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return set_bit(nr ^ (BITS_PER_LONG - 1), ptr);
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}
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static inline void clear_bit_inv(unsigned long nr, volatile unsigned long *ptr)
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{
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return clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
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}
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static inline bool test_and_clear_bit_inv(unsigned long nr,
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volatile unsigned long *ptr)
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{
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return test_and_clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
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}
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static inline void __set_bit_inv(unsigned long nr, volatile unsigned long *ptr)
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{
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return __set_bit(nr ^ (BITS_PER_LONG - 1), ptr);
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}
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static inline void __clear_bit_inv(unsigned long nr, volatile unsigned long *ptr)
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{
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return __clear_bit(nr ^ (BITS_PER_LONG - 1), ptr);
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}
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static inline bool test_bit_inv(unsigned long nr,
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const volatile unsigned long *ptr)
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{
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return test_bit(nr ^ (BITS_PER_LONG - 1), ptr);
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}
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/**
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* __flogr - find leftmost one
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* @word - The word to search
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*
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* Returns the bit number of the most significant bit set,
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* where the most significant bit has bit number 0.
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* If no bit is set this function returns 64.
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*/
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static inline unsigned char __flogr(unsigned long word)
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{
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if (__builtin_constant_p(word)) {
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unsigned long bit = 0;
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if (!word)
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return 64;
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if (!(word & 0xffffffff00000000UL)) {
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word <<= 32;
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bit += 32;
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}
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if (!(word & 0xffff000000000000UL)) {
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word <<= 16;
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bit += 16;
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}
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if (!(word & 0xff00000000000000UL)) {
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word <<= 8;
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bit += 8;
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}
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if (!(word & 0xf000000000000000UL)) {
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word <<= 4;
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bit += 4;
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}
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if (!(word & 0xc000000000000000UL)) {
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word <<= 2;
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bit += 2;
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}
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if (!(word & 0x8000000000000000UL)) {
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word <<= 1;
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bit += 1;
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}
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return bit;
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} else {
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union register_pair rp;
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rp.even = word;
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asm volatile(
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" flogr %[rp],%[rp]\n"
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: [rp] "+d" (rp.pair) : : "cc");
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return rp.even;
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}
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}
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/**
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* __ffs - find first bit in word.
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* @word: The word to search
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*
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* Undefined if no bit exists, so code should check against 0 first.
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*/
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static inline unsigned long __ffs(unsigned long word)
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{
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return __flogr(-word & word) ^ (BITS_PER_LONG - 1);
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}
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/**
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* ffs - find first bit set
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* @word: the word to search
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*
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* This is defined the same way as the libc and
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* compiler builtin ffs routines (man ffs).
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*/
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static inline int ffs(int word)
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{
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unsigned long mask = 2 * BITS_PER_LONG - 1;
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unsigned int val = (unsigned int)word;
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return (1 + (__flogr(-val & val) ^ (BITS_PER_LONG - 1))) & mask;
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}
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/**
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* __fls - find last (most-significant) set bit in a long word
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* @word: the word to search
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*
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* Undefined if no set bit exists, so code should check against 0 first.
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*/
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static inline unsigned long __fls(unsigned long word)
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{
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return __flogr(word) ^ (BITS_PER_LONG - 1);
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}
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/**
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* fls64 - find last set bit in a 64-bit word
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* @word: the word to search
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*
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* This is defined in a similar way as the libc and compiler builtin
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* ffsll, but returns the position of the most significant set bit.
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*
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* fls64(value) returns 0 if value is 0 or the position of the last
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* set bit if value is nonzero. The last (most significant) bit is
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* at position 64.
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*/
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static inline int fls64(unsigned long word)
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{
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unsigned long mask = 2 * BITS_PER_LONG - 1;
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return (1 + (__flogr(word) ^ (BITS_PER_LONG - 1))) & mask;
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}
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/**
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* fls - find last (most-significant) bit set
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* @word: the word to search
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*
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* This is defined the same way as ffs.
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static inline int fls(unsigned int word)
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{
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return fls64(word);
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}
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#include <asm-generic/bitops/ffz.h>
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#include <asm-generic/bitops/hweight.h>
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#include <asm-generic/bitops/sched.h>
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#include <asm-generic/bitops/le.h>
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#include <asm-generic/bitops/ext2-atomic-setbit.h>
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#endif /* _S390_BITOPS_H */
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