root/arch/unicore32/include/asm/cmpxchg.h

INCLUDED FROM

DEFINITIONS

1. __xchg

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Atomics xchg/cmpxchg for PKUnity SoC and UniCore ISA
   4  *
   5  * Copyright (C) 2001-2012 GUAN Xue-tao
   6  */
   7 #ifndef __UNICORE_CMPXCHG_H__
   8 #define __UNICORE_CMPXCHG_H__
   9 
  10 /*
  11  * Generate a link failure on undefined symbol if the pointer points to a value
  12  * of unsupported size.
  13  */
  14 extern void __xchg_bad_pointer(void);
  15 
  16 static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
  17                 int size)
  18 {
  19         unsigned long ret;
  20 
  21         switch (size) {
  22         case 1:
  23                 asm volatile("swapb     %0, %1, [%2]"
  24                         : "=&r" (ret)
  25                         : "r" (x), "r" (ptr)
  26                         : "memory", "cc");
  27                 break;
  28         case 4:
  29                 asm volatile("swapw     %0, %1, [%2]"
  30                         : "=&r" (ret)
  31                         : "r" (x), "r" (ptr)
  32                         : "memory", "cc");
  33                 break;
  34         default:
  35                 __xchg_bad_pointer();
  36         }
  37 
  38         return ret;
  39 }
  40 
  41 #define xchg(ptr, x) \
  42         ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
  43 
  44 #include <asm-generic/cmpxchg-local.h>
  45 
  46 /*
  47  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  48  * them available.
  49  */
  50 #define cmpxchg_local(ptr, o, n)                                        \
  51                 ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr),     \
  52                 (unsigned long)(o), (unsigned long)(n), sizeof(*(ptr))))
  53 #define cmpxchg64_local(ptr, o, n)                                      \
  54                 __cmpxchg64_local_generic((ptr), (o), (n))
  55 
  56 #include <asm-generic/cmpxchg.h>
  57 
  58 #endif /* __UNICORE_CMPXCHG_H__ */