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) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  44
  45 void __xchg_called_with_bad_pointer(void);
  46
  47 static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
  48                                        int size)
  49 {
  50         switch (size) {
  51         case 4:
  52                 return xchg32(ptr, x);
  53         case 8:
  54                 return xchg64(ptr, x);
  55         }
  56         __xchg_called_with_bad_pointer();
  57         return x;
  58 }
  59
  60 /*
  61  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  62  * store NEW in MEM.  Return the initial value in MEM.  Success is
  63  * indicated by comparing RETURN with OLD.
  64  */
  65
  66 #include <asm-generic/cmpxchg-local.h>
  67
  68 #define __HAVE_ARCH_CMPXCHG 1
  69
  70 static inline unsigned long
  71 __cmpxchg_u32(volatile int *m, int old, int new)
  72 {
  73         __asm__ __volatile__("cas [%2], %3, %0"
  74                              : "=&r" (new)
  75                              : "0" (new), "r" (m), "r" (old)
  76                              : "memory");
  77
  78         return new;
  79 }
  80
  81 static inline unsigned long
  82 __cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
  83 {
  84         __asm__ __volatile__("casx [%2], %3, %0"
  85                              : "=&r" (new)
  86                              : "0" (new), "r" (m), "r" (old)
  87                              : "memory");
  88
  89         return new;
  90 }
  91
  92 /* This function doesn't exist, so you'll get a linker error
  93    if something tries to do an invalid cmpxchg().  */
  94 void __cmpxchg_called_with_bad_pointer(void);
  95
  96 static inline unsigned long
  97 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
  98 {
  99         switch (size) {
 100                 case 4:
 101                         return __cmpxchg_u32(ptr, old, new);
 102                 case 8:
 103                         return __cmpxchg_u64(ptr, old, new);
 104         }
 105         __cmpxchg_called_with_bad_pointer();
 106         return old;
 107 }
 108
 109 #define cmpxchg(ptr,o,n)                                                 \
 110   ({                                                                     \
 111      __typeof__(*(ptr)) _o_ = (o);                                       \
 112      __typeof__(*(ptr)) _n_ = (n);                                       \
 113      (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,           \
 114                                     (unsigned long)_n_, sizeof(*(ptr))); \
 115   })
 116
 117 /*
 118  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 119  * them available.
 120  */
 121
 122 static inline unsigned long __cmpxchg_local(volatile void *ptr,
 123                                       unsigned long old,
 124                                       unsigned long new, int size)
 125 {
 126         switch (size) {
 127         case 4:
 128         case 8: return __cmpxchg(ptr, old, new, size);
 129         default:
 130                 return __cmpxchg_local_generic(ptr, old, new, size);
 131         }
 132
 133         return old;
 134 }
 135
 136 #define cmpxchg_local(ptr, o, n)                                        \
 137         ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 138                         (unsigned long)(n), sizeof(*(ptr))))
 139 #define cmpxchg64_local(ptr, o, n)                                      \
 140   ({                                                                    \
 141         BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 142         cmpxchg_local((ptr), (o), (n));                                 \
 143   })
 144 #define cmpxchg64(ptr, o, n)    cmpxchg64_local((ptr), (o), (n))
 145
 146 #endif /* __ARCH_SPARC64_CMPXCHG__ */