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