linux/arch/arm64/include/asm/atomic.h
Will Deacon 6059a7b6e8 arm64: atomics: implement atomic{,64}_cmpxchg using cmpxchg
We don't need duplicate cmpxchg implementations, so use cmpxchg to
implement atomic{,64}_cmpxchg, like we do for xchg already.

Reviewed-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-07-27 15:28:53 +01:00

96 lines
3.1 KiB
C

/*
* Based on arch/arm/include/asm/atomic.h
*
* Copyright (C) 1996 Russell King.
* Copyright (C) 2002 Deep Blue Solutions Ltd.
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_ATOMIC_H
#define __ASM_ATOMIC_H
#include <linux/compiler.h>
#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/lse.h>
#ifdef __KERNEL__
#define __ARM64_IN_ATOMIC_IMPL
#if defined(CONFIG_ARM64_LSE_ATOMICS) && defined(CONFIG_AS_LSE)
#include <asm/atomic_lse.h>
#else
#include <asm/atomic_ll_sc.h>
#endif
#undef __ARM64_IN_ATOMIC_IMPL
#include <asm/cmpxchg.h>
#define ___atomic_add_unless(v, a, u, sfx) \
({ \
typeof((v)->counter) c, old; \
\
c = atomic##sfx##_read(v); \
while (c != (u) && \
(old = atomic##sfx##_cmpxchg((v), c, c + (a))) != c) \
c = old; \
c; \
})
#define ATOMIC_INIT(i) { (i) }
#define atomic_read(v) READ_ONCE((v)->counter)
#define atomic_set(v, i) (((v)->counter) = (i))
#define atomic_xchg(v, new) xchg(&((v)->counter), (new))
#define atomic_cmpxchg(v, old, new) cmpxchg(&((v)->counter), (old), (new))
#define atomic_inc(v) atomic_add(1, (v))
#define atomic_dec(v) atomic_sub(1, (v))
#define atomic_inc_return(v) atomic_add_return(1, (v))
#define atomic_dec_return(v) atomic_sub_return(1, (v))
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
#define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0)
#define __atomic_add_unless(v, a, u) ___atomic_add_unless(v, a, u,)
#define atomic_andnot atomic_andnot
/*
* 64-bit atomic operations.
*/
#define ATOMIC64_INIT ATOMIC_INIT
#define atomic64_read atomic_read
#define atomic64_set atomic_set
#define atomic64_xchg atomic_xchg
#define atomic64_cmpxchg atomic_cmpxchg
#define atomic64_inc(v) atomic64_add(1, (v))
#define atomic64_dec(v) atomic64_sub(1, (v))
#define atomic64_inc_return(v) atomic64_add_return(1, (v))
#define atomic64_dec_return(v) atomic64_sub_return(1, (v))
#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
#define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0)
#define atomic64_sub_and_test(i, v) (atomic64_sub_return((i), (v)) == 0)
#define atomic64_add_negative(i, v) (atomic64_add_return((i), (v)) < 0)
#define atomic64_add_unless(v, a, u) (___atomic_add_unless(v, a, u, 64) != u)
#define atomic64_andnot atomic64_andnot
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
#endif
#endif