arch/unicore32/include/asm/cmpxchg.h

   1 /*
   2  * Atomics xchg/cmpxchg for PKUnity SoC and UniCore ISA
   3  *
   4  * Copyright (C) 2001-2012 GUAN Xue-tao
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #ifndef __UNICORE_CMPXCHG_H__
  11 #define __UNICORE_CMPXCHG_H__
  12
  13 /*
  14  * Generate a link failure on undefined symbol if the pointer points to a value
  15  * of unsupported size.
  16  */
  17 extern void __xchg_bad_pointer(void);
  18
  19 static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
  20                 int size)
  21 {
  22         unsigned long ret;
  23
  24         switch (size) {
  25         case 1:
  26                 asm volatile("swapb     %0, %1, [%2]"
  27                         : "=&r" (ret)
  28                         : "r" (x), "r" (ptr)
  29                         : "memory", "cc");
  30                 break;
  31         case 4:
  32                 asm volatile("swapw     %0, %1, [%2]"
  33                         : "=&r" (ret)
  34                         : "r" (x), "r" (ptr)
  35                         : "memory", "cc");
  36                 break;
  37         default:
  38                 __xchg_bad_pointer();
  39         }
  40
  41         return ret;
  42 }
  43
  44 #define xchg(ptr, x) \
  45         ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
  46
  47 #include <asm-generic/cmpxchg-local.h>
  48
  49 /*
  50  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  51  * them available.
  52  */
  53 #define cmpxchg_local(ptr, o, n)                                        \
  54                 ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr),     \
  55                 (unsigned long)(o), (unsigned long)(n), sizeof(*(ptr))))
  56 #define cmpxchg64_local(ptr, o, n)                                      \
  57                 __cmpxchg64_local_generic((ptr), (o), (n))
  58
  59 #include <asm-generic/cmpxchg.h>
  60
  61 #endif /* __UNICORE_CMPXCHG_H__ */