-extern void set_usable_vm(unsigned long start, unsigned long end);
-extern void set_kmem_end(unsigned long new);
+extern int phys_mapping(unsigned long phys, __u64 *offset_out);
+extern int physmem_subst_mapping(void *virt, int fd, __u64 offset, int w);
+extern int is_remapped(void *virt);
+extern int physmem_remove_mapping(void *virt);
+extern void physmem_forget_descriptor(int fd);