arch/sparc/include/asm/cmpxchg_64.h

   1 /* 64-bit atomic xchg() and cmpxchg() definitions.
   2  *
   3  * Copyright (C) 1996, 1997, 2000 David S. Miller (davem@redhat.com)
   4  */
   5
   6 #ifndef __ARCH_SPARC64_CMPXCHG__
   7 #define __ARCH_SPARC64_CMPXCHG__
   8
   9 static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
  10 {
  11         unsigned long tmp1, tmp2;
  12
  13         __asm__ __volatile__(
  14 "       mov             %0, %1\n"
  15 "1:     lduw            [%4], %2\n"
  16 "       cas             [%4], %2, %0\n"
  17 "       cmp             %2, %0\n"
  18 "       bne,a,pn        %%icc, 1b\n"
  19 "        mov            %1, %0\n"
  20         : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
  21         : "0" (val), "r" (m)
  22         : "cc", "memory");
  23         return val;
  24 }
  25
  26 static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long val)
  27 {
  28         unsigned long tmp1, tmp2;
  29
  30         __asm__ __volatile__(
  31 "       mov             %0, %1\n"
  32 "1:     ldx             [%4], %2\n"
  33 "       casx            [%4], %2, %0\n"
  34 "       cmp             %2, %0\n"
  35 "       bne,a,pn        %%xcc, 1b\n"
  36 "        mov            %1, %0\n"
  37         : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
  38         : "0" (val), "r" (m)
  39         : "cc", "memory");
  40         return val;
  41 }
  42
  43 #define xchg(ptr,x)                                                     \
  44 ({      __typeof__(*(ptr)) __ret;                                       \
  45         __ret = (__typeof__(*(ptr)))                                    \
  46                 __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)));      \
  47         __ret;                                                          \
  48 })
  49
  50 void __xchg_called_with_bad_pointer(void);
  51
  52 static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
  53                                        int size)
  54 {
  55         switch (size) {
  56         case 4:
  57                 return xchg32(ptr, x);
  58         case 8:
  59                 return xchg64(ptr, x);
  60         }
  61         __xchg_called_with_bad_pointer();
  62         return x;
  63 }
  64
  65 /*
  66  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  67  * store NEW in MEM.  Return the initial value in MEM.  Success is
  68  * indicated by comparing RETURN with OLD.
  69  */
  70
  71 #include <asm-generic/cmpxchg-local.h>
  72
  73 static inline unsigned long
  74 __cmpxchg_u32(volatile int *m, int old, int new)
  75 {
  76         __asm__ __volatile__("cas [%2], %3, %0"
  77                              : "=&r" (new)
  78                              : "0" (new), "r" (m), "r" (old)
  79                              : "memory");
  80
  81         return new;
  82 }
  83
  84 static inline unsigned long
  85 __cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
  86 {
  87         __asm__ __volatile__("casx [%2], %3, %0"
  88                              : "=&r" (new)
  89                              : "0" (new), "r" (m), "r" (old)
  90                              : "memory");
  91
  92         return new;
  93 }
  94
  95 /* This function doesn't exist, so you'll get a linker error
  96    if something tries to do an invalid cmpxchg().  */
  97 void __cmpxchg_called_with_bad_pointer(void);
  98
  99 static inline unsigned long
 100 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
 101 {
 102         switch (size) {
 103                 case 4:
 104                         return __cmpxchg_u32(ptr, old, new);
 105                 case 8:
 106                         return __cmpxchg_u64(ptr, old, new);
 107         }
 108         __cmpxchg_called_with_bad_pointer();
 109         return old;
 110 }
 111
 112 #define cmpxchg(ptr,o,n)                                                 \
 113   ({                                                                     \
 114      __typeof__(*(ptr)) _o_ = (o);                                       \
 115      __typeof__(*(ptr)) _n_ = (n);                                       \
 116      (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,           \
 117                                     (unsigned long)_n_, sizeof(*(ptr))); \
 118   })
 119
 120 /*
 121  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 122  * them available.
 123  */
 124
 125 static inline unsigned long __cmpxchg_local(volatile void *ptr,
 126                                       unsigned long old,
 127                                       unsigned long new, int size)
 128 {
 129         switch (size) {
 130         case 4:
 131         case 8: return __cmpxchg(ptr, old, new, size);
 132         default:
 133                 return __cmpxchg_local_generic(ptr, old, new, size);
 134         }
 135
 136         return old;
 137 }
 138
 139 #define cmpxchg_local(ptr, o, n)                                        \
 140         ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 141                         (unsigned long)(n), sizeof(*(ptr))))
 142 #define cmpxchg64_local(ptr, o, n)                                      \
 143   ({                                                                    \
 144         BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 145         cmpxchg_local((ptr), (o), (n));                                 \
 146   })
 147 #define cmpxchg64(ptr, o, n)    cmpxchg64_local((ptr), (o), (n))
 148
 149 #endif /* __ARCH_SPARC64_CMPXCHG__ */