-extern void __arch_writesb(unsigned long virt, const void *from, int len);
-extern void __arch_writesw(unsigned long virt, const void *from, int len);
-extern void __arch_writesl(unsigned long virt, const void *from, int len);
-extern void __arch_readsb(unsigned long virt, void *from, int len);
-extern void __arch_readsw(unsigned long virt, void *from, int len);
-extern void __arch_readsl(unsigned long virt, void *from, int len);
-