LXR linux/arch/parisc/include/asm/cmpxchg.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * forked from parisc asm/atomic.h which was:
   4 *      Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
   5 *      Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
   6 */
   7
   8#ifndef _ASM_PARISC_CMPXCHG_H_
   9#define _ASM_PARISC_CMPXCHG_H_
  10
  11/* This should get optimized out since it's never called.
  12** Or get a link error if xchg is used "wrong".
  13*/
  14extern void __xchg_called_with_bad_pointer(void);
  15
  16/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
  17extern unsigned long __xchg8(char, char *);
  18extern unsigned long __xchg32(int, int *);
  19#ifdef CONFIG_64BIT
  20extern unsigned long __xchg64(unsigned long, unsigned long *);
  21#endif
  22
  23/* optimizer better get rid of switch since size is a constant */
  24static inline unsigned long
  25__xchg(unsigned long x, __volatile__ void *ptr, int size)
  26{
  27        switch (size) {
  28#ifdef CONFIG_64BIT
  29        case 8: return __xchg64(x, (unsigned long *) ptr);
  30#endif
  31        case 4: return __xchg32((int) x, (int *) ptr);
  32        case 1: return __xchg8((char) x, (char *) ptr);
  33        }
  34        __xchg_called_with_bad_pointer();
  35        return x;
  36}
  37
  38/*
  39** REVISIT - Abandoned use of LDCW in xchg() for now:
  40** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
  41** o and while we are at it, could CONFIG_64BIT code use LDCD too?
  42**
  43**      if (__builtin_constant_p(x) && (x == NULL))
  44**              if (((unsigned long)p & 0xf) == 0)
  45**                      return __ldcw(p);
  46*/
  47#define xchg(ptr, x) \
  48        ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
  49
  50/* bug catcher for when unsupported size is used - won't link */
  51extern void __cmpxchg_called_with_bad_pointer(void);
  52
  53/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
  54extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
  55                                   unsigned int new_);
  56extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
  57
  58/* don't worry...optimizer will get rid of most of this */
  59static inline unsigned long
  60__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
  61{
  62        switch (size) {
  63#ifdef CONFIG_64BIT
  64        case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  65#endif
  66        case 4: return __cmpxchg_u32((unsigned int *)ptr,
  67                                     (unsigned int)old, (unsigned int)new_);
  68        }
  69        __cmpxchg_called_with_bad_pointer();
  70        return old;
  71}
  72
  73#define cmpxchg(ptr, o, n)                                               \
  74({                                                                       \
  75        __typeof__(*(ptr)) _o_ = (o);                                    \
  76        __typeof__(*(ptr)) _n_ = (n);                                    \
  77        (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,        \
  78                                    (unsigned long)_n_, sizeof(*(ptr))); \
  79})
  80
  81#include <asm-generic/cmpxchg-local.h>
  82
  83static inline unsigned long __cmpxchg_local(volatile void *ptr,
  84                                      unsigned long old,
  85                                      unsigned long new_, int size)
  86{
  87        switch (size) {
  88#ifdef CONFIG_64BIT
  89        case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  90#endif
  91        case 4: return __cmpxchg_u32(ptr, old, new_);
  92        default:
  93                return __cmpxchg_local_generic(ptr, old, new_, size);
  94        }
  95}
  96
  97/*
  98 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  99 * them available.
 100 */
 101#define cmpxchg_local(ptr, o, n)                                        \
 102        ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 103                        (unsigned long)(n), sizeof(*(ptr))))
 104#ifdef CONFIG_64BIT
 105#define cmpxchg64_local(ptr, o, n)                                      \
 106({                                                                      \
 107        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 108        cmpxchg_local((ptr), (o), (n));                                 \
 109})
 110#else
 111#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 112#endif
 113
 114#define cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
 115
 116#endif /* _ASM_PARISC_CMPXCHG_H_ */
 117