LXR linux/arch/m68k/include/asm/cmpxchg.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef __ARCH_M68K_CMPXCHG__
   3#define __ARCH_M68K_CMPXCHG__
   4
   5#include <linux/irqflags.h>
   6
   7struct __xchg_dummy { unsigned long a[100]; };
   8#define __xg(x) ((volatile struct __xchg_dummy *)(x))
   9
  10extern unsigned long __invalid_xchg_size(unsigned long, volatile void *, int);
  11
  12#ifndef CONFIG_RMW_INSNS
  13static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
  14{
  15        unsigned long flags, tmp;
  16
  17        local_irq_save(flags);
  18
  19        switch (size) {
  20        case 1:
  21                tmp = *(u8 *)ptr;
  22                *(u8 *)ptr = x;
  23                x = tmp;
  24                break;
  25        case 2:
  26                tmp = *(u16 *)ptr;
  27                *(u16 *)ptr = x;
  28                x = tmp;
  29                break;
  30        case 4:
  31                tmp = *(u32 *)ptr;
  32                *(u32 *)ptr = x;
  33                x = tmp;
  34                break;
  35        default:
  36                tmp = __invalid_xchg_size(x, ptr, size);
  37                break;
  38        }
  39
  40        local_irq_restore(flags);
  41        return x;
  42}
  43#else
  44static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
  45{
  46        switch (size) {
  47        case 1:
  48                __asm__ __volatile__
  49                        ("moveb %2,%0\n\t"
  50                         "1:\n\t"
  51                         "casb %0,%1,%2\n\t"
  52                         "jne 1b"
  53                         : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
  54                break;
  55        case 2:
  56                __asm__ __volatile__
  57                        ("movew %2,%0\n\t"
  58                         "1:\n\t"
  59                         "casw %0,%1,%2\n\t"
  60                         "jne 1b"
  61                         : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
  62                break;
  63        case 4:
  64                __asm__ __volatile__
  65                        ("movel %2,%0\n\t"
  66                         "1:\n\t"
  67                         "casl %0,%1,%2\n\t"
  68                         "jne 1b"
  69                         : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
  70                break;
  71        default:
  72                x = __invalid_xchg_size(x, ptr, size);
  73                break;
  74        }
  75        return x;
  76}
  77#endif
  78
  79#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  80
  81#include <asm-generic/cmpxchg-local.h>
  82
  83#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
  84
  85extern unsigned long __invalid_cmpxchg_size(volatile void *,
  86                                            unsigned long, unsigned long, int);
  87
  88/*
  89 * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  90 * store NEW in MEM.  Return the initial value in MEM.  Success is
  91 * indicated by comparing RETURN with OLD.
  92 */
  93#ifdef CONFIG_RMW_INSNS
  94
  95static inline unsigned long __cmpxchg(volatile void *p, unsigned long old,
  96                                      unsigned long new, int size)
  97{
  98        switch (size) {
  99        case 1:
 100                __asm__ __volatile__ ("casb %0,%2,%1"
 101                                      : "=d" (old), "=m" (*(char *)p)
 102                                      : "d" (new), "0" (old), "m" (*(char *)p));
 103                break;
 104        case 2:
 105                __asm__ __volatile__ ("casw %0,%2,%1"
 106                                      : "=d" (old), "=m" (*(short *)p)
 107                                      : "d" (new), "0" (old), "m" (*(short *)p));
 108                break;
 109        case 4:
 110                __asm__ __volatile__ ("casl %0,%2,%1"
 111                                      : "=d" (old), "=m" (*(int *)p)
 112                                      : "d" (new), "0" (old), "m" (*(int *)p));
 113                break;
 114        default:
 115                old = __invalid_cmpxchg_size(p, old, new, size);
 116                break;
 117        }
 118        return old;
 119}
 120
 121#define cmpxchg(ptr, o, n)                                                  \
 122        ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),           \
 123                        (unsigned long)(n), sizeof(*(ptr))))
 124#define cmpxchg_local(ptr, o, n)                                            \
 125        ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),           \
 126                        (unsigned long)(n), sizeof(*(ptr))))
 127
 128#define cmpxchg64(ptr, o, n)    cmpxchg64_local((ptr), (o), (n))
 129
 130#else
 131
 132#include <asm-generic/cmpxchg.h>
 133
 134#endif
 135
 136#endif /* __ARCH_M68K_CMPXCHG__ */
 137