kernel/arch/m68k/include/asm/cmpxchg.h

   1 #ifndef __ARCH_M68K_CMPXCHG__
   2 #define __ARCH_M68K_CMPXCHG__
   3
   4 #include <linux/irqflags.h>
   5
   6 struct __xchg_dummy { unsigned long a[100]; };
   7 #define __xg(x) ((volatile struct __xchg_dummy *)(x))
   8
   9 extern unsigned long __invalid_xchg_size(unsigned long, volatile void *, int);
  10
  11 #ifndef CONFIG_RMW_INSNS
  12 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
  13 {
  14         unsigned long flags, tmp;
  15
  16         local_irq_save(flags);
  17
  18         switch (size) {
  19         case 1:
  20                 tmp = *(u8 *)ptr;
  21                 *(u8 *)ptr = x;
  22                 x = tmp;
  23                 break;
  24         case 2:
  25                 tmp = *(u16 *)ptr;
  26                 *(u16 *)ptr = x;
  27                 x = tmp;
  28                 break;
  29         case 4:
  30                 tmp = *(u32 *)ptr;
  31                 *(u32 *)ptr = x;
  32                 x = tmp;
  33                 break;
  34         default:
  35                 tmp = __invalid_xchg_size(x, ptr, size);
  36                 break;
  37         }
  38
  39         local_irq_restore(flags);
  40         return x;
  41 }
  42 #else
  43 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
  44 {
  45         switch (size) {
  46         case 1:
  47                 __asm__ __volatile__
  48                         ("moveb %2,%0\n\t"
  49                          "1:\n\t"
  50                          "casb %0,%1,%2\n\t"
  51                          "jne 1b"
  52                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
  53                 break;
  54         case 2:
  55                 __asm__ __volatile__
  56                         ("movew %2,%0\n\t"
  57                          "1:\n\t"
  58                          "casw %0,%1,%2\n\t"
  59                          "jne 1b"
  60                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
  61                 break;
  62         case 4:
  63                 __asm__ __volatile__
  64                         ("movel %2,%0\n\t"
  65                          "1:\n\t"
  66                          "casl %0,%1,%2\n\t"
  67                          "jne 1b"
  68                          : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
  69                 break;
  70         default:
  71                 x = __invalid_xchg_size(x, ptr, size);
  72                 break;
  73         }
  74         return x;
  75 }
  76 #endif
  77
  78 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  79
  80 #include <asm-generic/cmpxchg-local.h>
  81
  82 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
  83
  84 extern unsigned long __invalid_cmpxchg_size(volatile void *,
  85                                             unsigned long, unsigned long, int);
  86
  87 /*
  88  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  89  * store NEW in MEM.  Return the initial value in MEM.  Success is
  90  * indicated by comparing RETURN with OLD.
  91  */
  92 #ifdef CONFIG_RMW_INSNS
  93 #define __HAVE_ARCH_CMPXCHG     1
  94
  95 static inline unsigned long __cmpxchg(volatile void *p, unsigned long old,
  96                                       unsigned long new, int size)
  97 {
  98         switch (size) {
  99         case 1:
 100                 __asm__ __volatile__ ("casb %0,%2,%1"
 101                                       : "=d" (old), "=m" (*(char *)p)
 102                                       : "d" (new), "0" (old), "m" (*(char *)p));
 103                 break;
 104         case 2:
 105                 __asm__ __volatile__ ("casw %0,%2,%1"
 106                                       : "=d" (old), "=m" (*(short *)p)
 107                                       : "d" (new), "0" (old), "m" (*(short *)p));
 108                 break;
 109         case 4:
 110                 __asm__ __volatile__ ("casl %0,%2,%1"
 111                                       : "=d" (old), "=m" (*(int *)p)
 112                                       : "d" (new), "0" (old), "m" (*(int *)p));
 113                 break;
 114         default:
 115                 old = __invalid_cmpxchg_size(p, old, new, size);
 116                 break;
 117         }
 118         return old;
 119 }
 120
 121 #define cmpxchg(ptr, o, n)                                                  \
 122         ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),           \
 123                         (unsigned long)(n), sizeof(*(ptr))))
 124 #define cmpxchg_local(ptr, o, n)                                            \
 125         ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),           \
 126                         (unsigned long)(n), sizeof(*(ptr))))
 127
 128 #define cmpxchg64(ptr, o, n)    cmpxchg64_local((ptr), (o), (n))
 129
 130 #else
 131
 132 /*
 133  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 134  * them available.
 135  */
 136 #define cmpxchg_local(ptr, o, n)                                               \
 137         ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
 138                         (unsigned long)(n), sizeof(*(ptr))))
 139
 140 #include <asm-generic/cmpxchg.h>
 141
 142 #endif
 143
 144 #endif /* __ARCH_M68K_CMPXCHG__ */