LXR linux/arch/unicore32/include/asm/cmpxchg.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Atomics xchg/cmpxchg for PKUnity SoC and UniCore ISA
   4 *
   5 * Copyright (C) 2001-2012 GUAN Xue-tao
   6 */
   7#ifndef __UNICORE_CMPXCHG_H__
   8#define __UNICORE_CMPXCHG_H__
   9
  10/*
  11 * Generate a link failure on undefined symbol if the pointer points to a value
  12 * of unsupported size.
  13 */
  14extern void __xchg_bad_pointer(void);
  15
  16static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
  17                int size)
  18{
  19        unsigned long ret;
  20
  21        switch (size) {
  22        case 1:
  23                asm volatile("swapb     %0, %1, [%2]"
  24                        : "=&r" (ret)
  25                        : "r" (x), "r" (ptr)
  26                        : "memory", "cc");
  27                break;
  28        case 4:
  29                asm volatile("swapw     %0, %1, [%2]"
  30                        : "=&r" (ret)
  31                        : "r" (x), "r" (ptr)
  32                        : "memory", "cc");
  33                break;
  34        default:
  35                __xchg_bad_pointer();
  36        }
  37
  38        return ret;
  39}
  40
  41#define xchg(ptr, x) \
  42        ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
  43
  44#include <asm-generic/cmpxchg-local.h>
  45
  46/*
  47 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  48 * them available.
  49 */
  50#define cmpxchg_local(ptr, o, n)                                        \
  51                ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr),     \
  52                (unsigned long)(o), (unsigned long)(n), sizeof(*(ptr))))
  53#define cmpxchg64_local(ptr, o, n)                                      \
  54                __cmpxchg64_local_generic((ptr), (o), (n))
  55
  56#include <asm-generic/cmpxchg.h>
  57
  58#endif /* __UNICORE_CMPXCHG_H__ */
  59