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 ({                                                                      \
  48         __typeof__(*(ptr)) __ret;                                       \
  49         __typeof__(*(ptr)) _x_ = (x);                                   \
  50         __ret = (__typeof__(*(ptr)))                                    \
  51                 __xchg((unsigned long)_x_, (ptr), sizeof(*(ptr)));      \
  52         __ret;                                                          \
  53 })
  54
  55 /* bug catcher for when unsupported size is used - won't link */
  56 extern void __cmpxchg_called_with_bad_pointer(void);
  57
  58 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
  59 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
  60                                    unsigned int new_);
  61 extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
  62 extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_);
  63
  64 /* don't worry...optimizer will get rid of most of this */
  65 static inline unsigned long
  66 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
  67 {
  68         switch (size) {
  69 #ifdef CONFIG_64BIT
  70         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  71 #endif
  72         case 4: return __cmpxchg_u32((unsigned int *)ptr,
  73                                      (unsigned int)old, (unsigned int)new_);
  74         case 1: return __cmpxchg_u8((u8 *)ptr, old & 0xff, new_ & 0xff);
  75         }
  76         __cmpxchg_called_with_bad_pointer();
  77         return old;
  78 }
  79
  80 #define cmpxchg(ptr, o, n)                                               \
  81 ({                                                                       \
  82         __typeof__(*(ptr)) _o_ = (o);                                    \
  83         __typeof__(*(ptr)) _n_ = (n);                                    \
  84         (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,        \
  85                                     (unsigned long)_n_, sizeof(*(ptr))); \
  86 })
  87
  88 #include <asm-generic/cmpxchg-local.h>
  89
  90 static inline unsigned long __cmpxchg_local(volatile void *ptr,
  91                                       unsigned long old,
  92                                       unsigned long new_, int size)
  93 {
  94         switch (size) {
  95 #ifdef CONFIG_64BIT
  96         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  97 #endif
  98         case 4: return __cmpxchg_u32(ptr, old, new_);
  99         default:
 100                 return __cmpxchg_local_generic(ptr, old, new_, size);
 101         }
 102 }
 103
 104 /*
 105  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 106  * them available.
 107  */
 108 #define cmpxchg_local(ptr, o, n)                                        \
 109         ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 110                         (unsigned long)(n), sizeof(*(ptr))))
 111 #ifdef CONFIG_64BIT
 112 #define cmpxchg64_local(ptr, o, n)                                      \
 113 ({                                                                      \
 114         BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 115         cmpxchg_local((ptr), (o), (n));                                 \
 116 })
 117 #else
 118 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 119 #endif
 120
 121 #define cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
 122
 123 #endif /* _ASM_PARISC_CMPXCHG_H_ */