d0e03218ca
Now that asm-generic/atomic.h is only used by architectures without any architecture-specific atomic definitions, we know that there will be no architecture-specific implementations to override, and can remove the ifdeffery this has previously required, bringing it into line with asm-generic/atomic64.h. At the same time, we can implement atomic_add() and atomic_sub() directly using ATOMIC_OP(), since we know architectures won't provide atomic_add_return() or atomic_sub_return(). There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210525140232.53872-9-mark.rutland@arm.com
122 lines
2.8 KiB
C
122 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Generic C implementation of atomic counter operations. Do not include in
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* machine independent code.
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#ifndef __ASM_GENERIC_ATOMIC_H
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#define __ASM_GENERIC_ATOMIC_H
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#include <asm/cmpxchg.h>
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#include <asm/barrier.h>
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#ifdef CONFIG_SMP
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/* we can build all atomic primitives from cmpxchg */
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#define ATOMIC_OP(op, c_op) \
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static inline void atomic_##op(int i, atomic_t *v) \
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{ \
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int c, old; \
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\
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c = v->counter; \
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while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
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c = old; \
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}
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#define ATOMIC_OP_RETURN(op, c_op) \
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static inline int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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int c, old; \
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\
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c = v->counter; \
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while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
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c = old; \
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\
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return c c_op i; \
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}
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#define ATOMIC_FETCH_OP(op, c_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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int c, old; \
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\
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c = v->counter; \
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while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
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c = old; \
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\
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return c; \
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}
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#else
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#include <linux/irqflags.h>
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#define ATOMIC_OP(op, c_op) \
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static inline void atomic_##op(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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\
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raw_local_irq_save(flags); \
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v->counter = v->counter c_op i; \
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raw_local_irq_restore(flags); \
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}
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#define ATOMIC_OP_RETURN(op, c_op) \
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static inline int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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int ret; \
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\
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raw_local_irq_save(flags); \
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ret = (v->counter = v->counter c_op i); \
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raw_local_irq_restore(flags); \
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\
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return ret; \
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}
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#define ATOMIC_FETCH_OP(op, c_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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int ret; \
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\
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raw_local_irq_save(flags); \
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ret = v->counter; \
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v->counter = v->counter c_op i; \
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raw_local_irq_restore(flags); \
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\
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return ret; \
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}
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#endif /* CONFIG_SMP */
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ATOMIC_OP_RETURN(add, +)
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ATOMIC_OP_RETURN(sub, -)
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ATOMIC_FETCH_OP(add, +)
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ATOMIC_FETCH_OP(sub, -)
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ATOMIC_FETCH_OP(and, &)
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ATOMIC_FETCH_OP(or, |)
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ATOMIC_FETCH_OP(xor, ^)
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ATOMIC_OP(add, +)
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ATOMIC_OP(sub, -)
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ATOMIC_OP(and, &)
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ATOMIC_OP(or, |)
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ATOMIC_OP(xor, ^)
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#undef ATOMIC_FETCH_OP
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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#define atomic_read(v) READ_ONCE((v)->counter)
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#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
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#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
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#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
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#endif /* __ASM_GENERIC_ATOMIC_H */
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