arch/parisc/include/asm/cmpxchg.h

   1 /*
   2  * forked from parisc asm/atomic.h which was:
   3  *      Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
   4  *      Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
   5  */
   6
   7 #ifndef _ASM_PARISC_CMPXCHG_H_
   8 #define _ASM_PARISC_CMPXCHG_H_
   9
  10 /* This should get optimized out since it's never called.
  11 ** Or get a link error if xchg is used "wrong".
  12 */
  13 extern void __xchg_called_with_bad_pointer(void);
  14
  15 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */
  16 extern unsigned long __xchg8(char, char *);
  17 extern unsigned long __xchg32(int, int *);
  18 #ifdef CONFIG_64BIT
  19 extern unsigned long __xchg64(unsigned long, unsigned long *);
  20 #endif
  21
  22 /* optimizer better get rid of switch since size is a constant */
  23 static inline unsigned long
  24 __xchg(unsigned long x, __volatile__ void *ptr, int size)
  25 {
  26         switch (size) {
  27 #ifdef CONFIG_64BIT
  28         case 8: return __xchg64(x, (unsigned long *) ptr);
  29 #endif
  30         case 4: return __xchg32((int) x, (int *) ptr);
  31         case 1: return __xchg8((char) x, (char *) ptr);
  32         }
  33         __xchg_called_with_bad_pointer();
  34         return x;
  35 }
  36
  37 /*
  38 ** REVISIT - Abandoned use of LDCW in xchg() for now:
  39 ** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
  40 ** o and while we are at it, could CONFIG_64BIT code use LDCD too?
  41 **
  42 **      if (__builtin_constant_p(x) && (x == NULL))
  43 **              if (((unsigned long)p & 0xf) == 0)
  44 **                      return __ldcw(p);
  45 */
  46 #define xchg(ptr, x) \
  47         ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
  48
  49 /* bug catcher for when unsupported size is used - won't link */
  50 extern void __cmpxchg_called_with_bad_pointer(void);
  51
  52 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
  53 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
  54                                    unsigned int new_);
  55 extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
  56
  57 /* don't worry...optimizer will get rid of most of this */
  58 static inline unsigned long
  59 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
  60 {
  61         switch (size) {
  62 #ifdef CONFIG_64BIT
  63         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  64 #endif
  65         case 4: return __cmpxchg_u32((unsigned int *)ptr,
  66                                      (unsigned int)old, (unsigned int)new_);
  67         }
  68         __cmpxchg_called_with_bad_pointer();
  69         return old;
  70 }
  71
  72 #define cmpxchg(ptr, o, n)                                               \
  73 ({                                                                       \
  74         __typeof__(*(ptr)) _o_ = (o);                                    \
  75         __typeof__(*(ptr)) _n_ = (n);                                    \
  76         (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,        \
  77                                     (unsigned long)_n_, sizeof(*(ptr))); \
  78 })
  79
  80 #include <asm-generic/cmpxchg-local.h>
  81
  82 static inline unsigned long __cmpxchg_local(volatile void *ptr,
  83                                       unsigned long old,
  84                                       unsigned long new_, int size)
  85 {
  86         switch (size) {
  87 #ifdef CONFIG_64BIT
  88         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  89 #endif
  90         case 4: return __cmpxchg_u32(ptr, old, new_);
  91         default:
  92                 return __cmpxchg_local_generic(ptr, old, new_, size);
  93         }
  94 }
  95
  96 /*
  97  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  98  * them available.
  99  */
 100 #define cmpxchg_local(ptr, o, n)                                        \
 101         ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 102                         (unsigned long)(n), sizeof(*(ptr))))
 103 #ifdef CONFIG_64BIT
 104 #define cmpxchg64_local(ptr, o, n)                                      \
 105 ({                                                                      \
 106         BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 107         cmpxchg_local((ptr), (o), (n));                                 \
 108 })
 109 #else
 110 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 111 #endif
 112
 113 #define cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
 114
 115 #endif /* _ASM_PARISC_CMPXCHG_H_ */