Disintegrate asm/system.h for Microblaze

Disintegrate asm/system.h for Microblaze.  Not compiled.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: microblaze-uclinux@itee.uq.edu.au
diff --git a/arch/microblaze/include/asm/cmpxchg.h b/arch/microblaze/include/asm/cmpxchg.h
new file mode 100644
index 0000000..0094859a
--- /dev/null
+++ b/arch/microblaze/include/asm/cmpxchg.h
@@ -0,0 +1,40 @@
+#ifndef _ASM_MICROBLAZE_CMPXCHG_H
+#define _ASM_MICROBLAZE_CMPXCHG_H
+
+void __bad_xchg(volatile void *ptr, int size);
+
+static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
+								int size)
+{
+	unsigned long ret;
+	unsigned long flags;
+
+	switch (size) {
+	case 1:
+		local_irq_save(flags);
+		ret = *(volatile unsigned char *)ptr;
+		*(volatile unsigned char *)ptr = x;
+		local_irq_restore(flags);
+		break;
+
+	case 4:
+		local_irq_save(flags);
+		ret = *(volatile unsigned long *)ptr;
+		*(volatile unsigned long *)ptr = x;
+		local_irq_restore(flags);
+		break;
+	default:
+		__bad_xchg(ptr, size), ret = 0;
+		break;
+	}
+
+	return ret;
+}
+
+#define xchg(ptr, x) \
+	((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
+
+#include <asm-generic/cmpxchg.h>
+#include <asm-generic/cmpxchg-local.h>
+
+#endif /* _ASM_MICROBLAZE_CMPXCHG_H */