diff --git a/include/sys/param.h b/include/sys/param.h
index 3cbc066a2..a6a11e702 100644
--- a/include/sys/param.h
+++ b/include/sys/param.h
@@ -1,5 +1,9 @@
+#ifndef __SYS_PARAM_H__
+#define __SYS_PARAM_H__
 /*
 sys/param.h
 */
 
 #define MAXHOSTNAMELEN  256	/* max hostname size */
+
+#endif /* __SYS_PARAM_H__ */
diff --git a/include/sys/vm.h b/include/sys/vm.h
index 514e5e497..e60ce198f 100644
--- a/include/sys/vm.h
+++ b/include/sys/vm.h
@@ -1,3 +1,6 @@
+#ifndef __SYS_VM_H__
+#define __SYS_VM_H__
+
 /*
 sys/vm.h
 */
@@ -23,3 +26,4 @@ struct mapreqvm
 	void	*vaddr_ret;	
 };
 
+#endif /* __SYS_VM_H__ */
diff --git a/include/sys/vm_i386.h b/include/sys/vm_i386.h
index 7fd137ffd..152cd49e0 100644
--- a/include/sys/vm_i386.h
+++ b/include/sys/vm_i386.h
@@ -1,3 +1,5 @@
+#ifndef __SYS_VM_386_H__
+#define __SYS_VM_386_H__
 /*
 sys/vm_i386.h
 */
@@ -63,3 +65,5 @@ sys/vm_i386.h
 /* CPUID flags */
 #define CPUID1_EDX_PSE (1L <<  3)	/* Page Size Extension */
 #define CPUID1_EDX_PGE (1L << 13)	/* Page Global (bit) Enable */
+
+#endif /* __SYS_VM_386_H__ */