LXR linux/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*/
  13extern void __xchg_called_with_bad_pointer(void);
  14
  15/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
  16extern unsigned long __xchg8(char, char *);
  17extern unsigned long __xchg32(int, int *);
  18#ifdef CONFIG_64BIT
  19extern unsigned long __xchg64(unsigned long, unsigned long *);
  20#endif
  21
  22/* optimizer better get rid of switch since size is a constant */
  23static 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 */
  52extern void __cmpxchg_called_with_bad_pointer(void);
  53
  54/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
  55extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
  56                                   unsigned int new_);
  57extern 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 */
  61static 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
  85static 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_ */
 117