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Most architectures define the atomic/atomic64 xchg and cmpxchg operations in terms of arch_xchg and arch_cmpxchg respectfully. Add fallbacks for these cases and remove the trivial cases from arch code. On some architectures the existing definitions are kept as these are used to build other arch_atomic*() operations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230605070124.3741859-5-mark.rutland@arm.com
134 lines
3.3 KiB
C
134 lines
3.3 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 generic_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 = arch_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 generic_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 = arch_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 generic_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 = arch_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 generic_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 generic_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 generic_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 arch_atomic_add_return generic_atomic_add_return
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#define arch_atomic_sub_return generic_atomic_sub_return
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#define arch_atomic_fetch_add generic_atomic_fetch_add
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#define arch_atomic_fetch_sub generic_atomic_fetch_sub
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#define arch_atomic_fetch_and generic_atomic_fetch_and
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#define arch_atomic_fetch_or generic_atomic_fetch_or
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#define arch_atomic_fetch_xor generic_atomic_fetch_xor
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#define arch_atomic_add generic_atomic_add
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#define arch_atomic_sub generic_atomic_sub
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#define arch_atomic_and generic_atomic_and
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#define arch_atomic_or generic_atomic_or
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#define arch_atomic_xor generic_atomic_xor
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#define arch_atomic_read(v) READ_ONCE((v)->counter)
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#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
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#endif /* __ASM_GENERIC_ATOMIC_H */
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