e986a0d6cb
The atomic bitops can actually be implemented pretty efficiently using the atomic_*() ops, rather than explicit use of spinlocks. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Cc: yamada.masahiro@socionext.com Link: https://lore.kernel.org/lkml/1529412794-17720-7-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_GENERIC_BITOPS_ATOMIC_H_
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#define _ASM_GENERIC_BITOPS_ATOMIC_H_
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#include <linux/atomic.h>
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#include <linux/compiler.h>
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#include <asm/barrier.h>
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/*
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* Implementation of atomic bitops using atomic-fetch ops.
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* See Documentation/atomic_bitops.txt for details.
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*/
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static inline void set_bit(unsigned int nr, volatile unsigned long *p)
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{
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p += BIT_WORD(nr);
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atomic_long_or(BIT_MASK(nr), (atomic_long_t *)p);
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}
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static inline void clear_bit(unsigned int nr, volatile unsigned long *p)
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{
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p += BIT_WORD(nr);
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atomic_long_andnot(BIT_MASK(nr), (atomic_long_t *)p);
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}
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static inline void change_bit(unsigned int nr, volatile unsigned long *p)
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{
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p += BIT_WORD(nr);
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atomic_long_xor(BIT_MASK(nr), (atomic_long_t *)p);
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}
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static inline int test_and_set_bit(unsigned int nr, volatile unsigned long *p)
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{
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long old;
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unsigned long mask = BIT_MASK(nr);
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p += BIT_WORD(nr);
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if (READ_ONCE(*p) & mask)
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return 1;
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old = atomic_long_fetch_or(mask, (atomic_long_t *)p);
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return !!(old & mask);
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}
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static inline int test_and_clear_bit(unsigned int nr, volatile unsigned long *p)
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{
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long old;
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unsigned long mask = BIT_MASK(nr);
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p += BIT_WORD(nr);
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if (!(READ_ONCE(*p) & mask))
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return 0;
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old = atomic_long_fetch_andnot(mask, (atomic_long_t *)p);
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return !!(old & mask);
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}
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static inline int test_and_change_bit(unsigned int nr, volatile unsigned long *p)
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{
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long old;
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unsigned long mask = BIT_MASK(nr);
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p += BIT_WORD(nr);
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old = atomic_long_fetch_xor(mask, (atomic_long_t *)p);
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return !!(old & mask);
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}
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#endif /* _ASM_GENERIC_BITOPS_ATOMIC_H */
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