LXR linux/arch/sparc/include/asm/cmpxchg

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/* 32-bit atomic xchg() and cmpxchg() definitions.
   3 *
   4 * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
   5 * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
   6 * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
   7 *
   8 * Additions by Keith M Wesolowski (wesolows@foobazco.org) based
   9 * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
  10 */
  11
  12#ifndef __ARCH_SPARC_CMPXCHG__
  13#define __ARCH_SPARC_CMPXCHG__
  14
  15unsigned long __xchg_u32(volatile u32 *m, u32 new);
  16void __xchg_called_with_bad_pointer(void);
  17
  18static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, int size)
  19{
  20        switch (size) {
  21        case 4:
  22                return __xchg_u32(ptr, x);
  23        }
  24        __xchg_called_with_bad_pointer();
  25        return x;
  26}
  27
  28#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  29
  30/* Emulate cmpxchg() the same way we emulate atomics,
  31 * by hashing the object address and indexing into an array
  32 * of spinlocks to get a bit of performance...
  33 *
  34 * See arch/sparc/lib/atomic32.c for implementation.
  35 *
  36 * Cribbed from <asm-parisc/atomic.h>
  37 */
  38
  39/* bug catcher for when unsupported size is used - won't link */
  40void __cmpxchg_called_with_bad_pointer(void);
  41/* we only need to support cmpxchg of a u32 on sparc */
  42unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
  43
  44/* don't worry...optimizer will get rid of most of this */
  45static inline unsigned long
  46__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
  47{
  48        switch (size) {
  49        case 4:
  50                return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
  51        default:
  52                __cmpxchg_called_with_bad_pointer();
  53                break;
  54        }
  55        return old;
  56}
  57
  58#define cmpxchg(ptr, o, n)                                              \
  59({                                                                      \
  60        __typeof__(*(ptr)) _o_ = (o);                                   \
  61        __typeof__(*(ptr)) _n_ = (n);                                   \
  62        (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,       \
  63                        (unsigned long)_n_, sizeof(*(ptr)));            \
  64})
  65
  66u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new);
  67#define cmpxchg64(ptr, old, new)        __cmpxchg_u64(ptr, old, new)
  68
  69#include <asm-generic/cmpxchg-local.h>
  70
  71/*
  72 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  73 * them available.
  74 */
  75#define cmpxchg_local(ptr, o, n)                                               \
  76        ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
  77                        (unsigned long)(n), sizeof(*(ptr))))
  78#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
  79
  80#endif /* __ARCH_SPARC_CMPXCHG__ */
  81