diff --git a/kernel/include/hos_types.h b/kernel/include/hos_types.h
index 5921615..9048d78 100644
--- a/kernel/include/hos_types.h
+++ b/kernel/include/hos_types.h
@@ -40,6 +40,14 @@ typedef struct
     u32_t   ss;
 } int_stack_t;
 
+typedef struct
+{
+    u16_t   length;
+    u32_t   phys_addr;
+} __attribute__ ((packed)) gdtr_t;
+
+typedef gdtr_t idtr_t;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/kernel/mm/mm.h b/kernel/mm/mm.h
index 1562d32..cd6af87 100644
--- a/kernel/mm/mm.h
+++ b/kernel/mm/mm.h
@@ -29,12 +29,6 @@ int mm_map(u32_t virtual_address, u32_t physical_address,
 u32_t mm_early_page_alloc();
 u32_t mm_page_alloc();
 
-typedef struct
-{
-    u16_t   length;
-    u32_t   phys_addr;
-} __attribute__ ((packed)) gdtr_t;
-
 #define set_cr3(address) \
     __asm__ __volatile__ ("movl %0, %%cr3" : : "r" (address));