+extern void __xchg_called_with_bad_pointer(void);
+
+#define __xchg(ptr, x, size) \
+({ \
+ unsigned long __xchg__res; \
+ volatile void *__xchg_ptr = (ptr); \
+ switch (size) { \
+ case 4: \
+ __xchg__res = xchg_u32(__xchg_ptr, x); \
+ break; \
+ case 1: \
+ __xchg__res = xchg_u8(__xchg_ptr, x); \
+ break; \
+ default: \
+ __xchg_called_with_bad_pointer(); \
+ __xchg__res = x; \
+ break; \
+ } \
+ \
+ __xchg__res; \
+})
+
+#define xchg(ptr,x) \
+ ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
+
+static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
+ unsigned long new)
+{
+ __u32 retval;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ retval = *m;
+ if (retval == old)
+ *m = new;
+ local_irq_restore(flags); /* implies memory barrier */
+ return retval;
+}
+
+/* This function doesn't exist, so you'll get a linker error
+ * if something tries to do an invalid cmpxchg(). */
+extern void __cmpxchg_called_with_bad_pointer(void);
+
+#define __HAVE_ARCH_CMPXCHG 1
+
+static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
+ unsigned long new, int size)