diff --git a/service/ptos/head/arch/amd64/msr.h b/service/ptos/head/arch/amd64/msr.h
index 56a3acc..f357056 100644
--- a/service/ptos/head/arch/amd64/msr.h
+++ b/service/ptos/head/arch/amd64/msr.h
@@ -10,7 +10,7 @@
 #define _MACHINE_MSR_H_ 1
 
 #ifndef __ASSEMBLER__
-#include <stdef.h>
+#include <ptdef.h>
 #endif  /* !__ASSEMBLER__ */
 
 #define IA32_SPEC_CTL       0x00000048