text: /*
   * Based on arch/arm/include/asm/cmpxchg.h
   *
   * 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_CMPXCHG_H
  #define __ASM_CMPXCHG_H
  
  #include <linux/bug.h>
  
  #include <asm/atomic.h>
  #include <asm/barrier.h>
  #include <asm/lse.h>
  
  /*
   * We need separate acquire parameters for ll/sc and lse, since the full
   * barrier case is generated as release+dmb for the former and
   * acquire+release for the latter.
   */
  #define __XCHG_CASE(w, sz, name, mb, nop_lse, acq, acq_lse, rel, cl)	\
  static inline unsigned long __xchg_case_##name(unsigned long x,		\
  					       volatile void *ptr)	\
  {									\
  	unsigned long ret, tmp;						\
  									\
  	asm volatile(ARM64_LSE_ATOMIC_INSN(				\
  	/* LL/SC */							\
  	"	prfm	pstl1strm, %2\n"				\
  	"1:	ld" #acq "xr" #sz "\t%" #w "0, %2\n"			\
  	"	st" #rel "xr" #sz "\t%w1, %" #w "3, %2\n"		\
  	"	cbnz	%w1, 1b\n"					\
  	"	" #mb,							\
  	/* LSE atomics */						\
  	"	swp" #acq_lse #rel #sz "\t%" #w "3, %" #w "0, %2\n"	\
  		__nops(3)						\
  	"	" #nop_lse)						\
  	: "=&r" (ret), "=&r" (tmp), "+Q" (*(unsigned long *)ptr)	\
  	: "r" (x)							\
  	: cl);								\
  									\
  	return ret;							\
  }
  
  __XCHG_CASE(w, b,     1,        ,    ,  ,  ,  ,         )
  __XCHG_CASE(w, h,     2,        ,    ,  ,  ,  ,         )
  __XCHG_CASE(w,  ,     4,        ,    ,  ,  ,  ,         )
  __XCHG_CASE( ,  ,     8,        ,    ,  ,  ,  ,         )
  __XCHG_CASE(w, b, acq_1,        ,    , a, a,  , "memory")
  __XCHG_CASE(w, h, acq_2,        ,    , a, a,  , "memory")
  __XCHG_CASE(w,  , acq_4,        ,    , a, a,  , "memory")
  __XCHG_CASE( ,  , acq_8,        ,    , a, a,  , "memory")
  __XCHG_CASE(w, b, rel_1,        ,    ,  ,  , l, "memory")
  __XCHG_CASE(w, h, rel_2,        ,    ,  ,  , l, "memory")
  __XCHG_CASE(w,  , rel_4,        ,    ,  ,  , l, "memory")
  __XCHG_CASE( ,  , rel_8,        ,    ,  ,  , l, "memory")
  __XCHG_CASE(w, b,  mb_1, dmb ish, nop,  , a, l, "memory")
  __XCHG_CASE(w, h,  mb_2, dmb ish, nop,  , a, l, "memory")
  __XCHG_CASE(w,  ,  mb_4, dmb ish, nop,  , a, l, "memory")
  __XCHG_CASE( ,  ,  mb_8, dmb ish, nop,  , a, l, "memory")
  
  #undef __XCHG_CASE
  
  #define __XCHG_GEN(sfx)							\
  static inline unsigned long __xchg##sfx(unsigned long x,		\
  					volatile void *ptr,		\
  					int size)			\
  {									\
  	switch (size) {							\
  	case 1:								\
  		return __xchg_case##sfx##_1(x, ptr);			\
  	case 2:								\
  		return __xchg_case##sfx##_2(x, ptr);			\
  	case 4:								\
  		return __xchg_case##sfx##_4(x, ptr);			\
  	case 8:								\
  		return __xchg_case##sfx##_8(x, ptr);			\
  	default:							\
  		BUILD_BUG();						\
  	}								\
  									\
  	unreachable();							\
  }
  
  __XCHG_GEN()
  __XCHG_GEN(_acq)
  __XCHG_GEN(_rel)
  __XCHG_GEN(_mb)
  
  #undef __XCHG_GEN
  
  #define __xchg_wrapper(sfx, ptr, x)					\
  ({									\
  	__typeof__(*(ptr)) __ret;					\
  	__ret = (__typeof__(*(ptr)))					\
  		__xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
  	__ret;								\
  })
  
  /* xchg */
  #define xchg_relaxed(...)	__xchg_wrapper(    , __VA_ARGS__)
  #define xchg_acquire(...)	__xchg_wrapper(_acq, __VA_ARGS__)
  #define xchg_release(...)	__xchg_wrapper(_rel, __VA_ARGS__)
  #define xchg(...)		__xchg_wrapper( _mb, __VA_ARGS__)
  
  #define __CMPXCHG_GEN(sfx)						\
  static inline unsigned long __cmpxchg##sfx(volatile void *ptr,		\
  					   unsigned long old,		\
  					   unsigned long new,		\
  					   int size)			\
  {									\
  	switch (size) {							\
  	case 1:								\
  		return __cmpxchg_case##sfx##_1(ptr, (u8)old, new);	\
  	case 2:								\
  		return __cmpxchg_case##sfx##_2(ptr, (u16)old, new);	\
  	case 4:								\
  		return __cmpxchg_case##sfx##_4(ptr, old, new);		\
  	case 8:								\
  		return __cmpxchg_case##sfx##_8(ptr, old, new);		\
  	default:							\
  		BUILD_BUG();						\
  	}								\
  									\
  	unreachable();							\
  }
  
  __CMPXCHG_GEN()
  __CMPXCHG_GEN(_acq)
  __CMPXCHG_GEN(_rel)
  __CMPXCHG_GEN(_mb)
  
  #undef __CMPXCHG_GEN
  
  #define __cmpxchg_wrapper(sfx, ptr, o, n)				\
  ({									\
  	__typeof__(*(ptr)) __ret;					\
  	__ret = (__typeof__(*(ptr)))					\
  		__cmpxchg##sfx((ptr), (unsigned long)(o),		\
  				(unsigned long)(n), sizeof(*(ptr)));	\
  	__ret;								\
  })
  
  /* cmpxchg */
  #define cmpxchg_relaxed(...)	__cmpxchg_wrapper(    , __VA_ARGS__)
  #define cmpxchg_acquire(...)	__cmpxchg_wrapper(_acq, __VA_ARGS__)
  #define cmpxchg_release(...)	__cmpxchg_wrapper(_rel, __VA_ARGS__)
  #define cmpxchg(...)		__cmpxchg_wrapper( _mb, __VA_ARGS__)
  #define cmpxchg_local		cmpxchg_relaxed
  
  /* cmpxchg64 */
  #define cmpxchg64_relaxed	cmpxchg_relaxed
  #define cmpxchg64_acquire	cmpxchg_acquire
  #define cmpxchg64_release	cmpxchg_release
  #define cmpxchg64		cmpxchg
  #define cmpxchg64_local		cmpxchg_local
  
  /* cmpxchg_double */
  #define system_has_cmpxchg_double()     1
  
  #define __cmpxchg_double_check(ptr1, ptr2)					\
  ({										\
  	if (sizeof(*(ptr1)) != 8)						\
  		BUILD_BUG();							\
  	VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1);	\
  })
  
  #define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
  ({\
  	int __ret;\
  	__cmpxchg_double_check(ptr1, ptr2); \
  	__ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2), \
  				     (unsigned long)(n1), (unsigned long)(n2), \
  				     ptr1); \
  	__ret; \
  })
  
  #define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \
  ({\
  	int __ret;\
  	__cmpxchg_double_check(ptr1, ptr2); \
  	__ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2), \
  				  (unsigned long)(n1), (unsigned long)(n2), \
  				  ptr1); \
  	__ret; \
  })
  
  /* this_cpu_cmpxchg */
  #define _protect_cmpxchg_local(pcp, o, n)			\
  ({								\
  	typeof(*raw_cpu_ptr(&(pcp))) __ret;			\
  	preempt_disable();					\
  	__ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n);	\
  	preempt_enable();					\
  	__ret;							\
  })
  
  #define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
  #define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
  #define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
  #define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
  
  #define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2)		\
  ({									\
  	int __ret;							\
  	preempt_disable();						\
  	__ret = cmpxchg_double_local(	raw_cpu_ptr(&(ptr1)),		\
  					raw_cpu_ptr(&(ptr2)),		\
  					o1, o2, n1, n2);		\
  	preempt_enable();						\
  	__ret;								\
  })
  
  #define __CMPWAIT_CASE(w, sz, name)					\
  static inline void __cmpwait_case_##name(volatile void *ptr,		\
  					 unsigned long val)		\
  {									\
  	unsigned long tmp;						\
  									\
  	asm volatile(							\
  	"	sevl\n"							\
  	"	wfe\n"							\
  	"	ldxr" #sz "\t%" #w "[tmp], %[v]\n"			\
  	"	eor	%" #w "[tmp], %" #w "[tmp], %" #w "[val]\n"	\
  	"	cbnz	%" #w "[tmp], 1f\n"				\
  	"	wfe\n"							\
  	"1:"								\
  	: [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr)		\
  	: [val] "r" (val));						\
  }
  
  __CMPWAIT_CASE(w, b, 1);
  __CMPWAIT_CASE(w, h, 2);
  __CMPWAIT_CASE(w,  , 4);
  __CMPWAIT_CASE( ,  , 8);
  
  #undef __CMPWAIT_CASE
  
  #define __CMPWAIT_GEN(sfx)						\
  static inline void __cmpwait##sfx(volatile void *ptr,			\
  				  unsigned long val,			\
  				  int size)				\
  {									\
  	switch (size) {							\
  	case 1:								\
  		return __cmpwait_case##sfx##_1(ptr, (u8)val);		\
  	case 2:								\
  		return __cmpwait_case##sfx##_2(ptr, (u16)val);		\
  	case 4:								\
  		return __cmpwait_case##sfx##_4(ptr, val);		\
  	case 8:								\
  		return __cmpwait_case##sfx##_8(ptr, val);		\
  	default:							\
  		BUILD_BUG();						\
  	}								\
  									\
  	unreachable();							\
  }
  
  __CMPWAIT_GEN()
  
  #undef __CMPWAIT_GEN
  
  #define __cmpwait_relaxed(ptr, val) \
  	__cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr)))
  
  #endif	/* __ASM_CMPXCHG_H */
  