diff --git a/arch/s390/include/asm/vdso.h b/arch/s390/include/asm/vdso.h
index 787acd4..f9b02d3 100644
--- a/arch/s390/include/asm/vdso.h
+++ b/arch/s390/include/asm/vdso.h
@@ -42,8 +42,8 @@
 
 extern struct vdso_data *vdso_data;
 
-int vdso_alloc_per_cpu(struct _lowcore *lowcore);
-void vdso_free_per_cpu(struct _lowcore *lowcore);
+int vdso_alloc_per_cpu(struct lowcore *lowcore);
+void vdso_free_per_cpu(struct lowcore *lowcore);
 
 #endif /* __ASSEMBLY__ */
 #endif /* __S390_VDSO_H__ */