text: /*
   * 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
  