diff --git a/sys/compat/freebsd32/freebsd32_ipc.h b/sys/compat/freebsd32/freebsd32_ipc.h
index ac469585cafe..d1fa7f1cf8ca 100644
--- a/sys/compat/freebsd32/freebsd32_ipc.h
+++ b/sys/compat/freebsd32/freebsd32_ipc.h
@@ -181,6 +181,12 @@ struct shmid_ds32_old {
 	uint32_t	shm_internal;
 };
 
+union semun_old32 {
+	int		val;
+	uint32_t	buf;
+	uint32_t	array;
+};
+
 void	freebsd32_ipcperm_old_in(struct ipc_perm32_old *ip32,
 	    struct ipc_perm *ip);
 void	freebsd32_ipcperm_old_out(struct ipc_perm *ip,
diff --git a/sys/compat/freebsd32/freebsd32_proto.h b/sys/compat/freebsd32/freebsd32_proto.h
index 34ba0974c9b9..c3a7dd241c47 100644
--- a/sys/compat/freebsd32/freebsd32_proto.h
+++ b/sys/compat/freebsd32/freebsd32_proto.h
@@ -1171,7 +1171,7 @@ struct freebsd7_freebsd32_semctl_args {
 	char semid_l_[PADL_(int)]; int semid; char semid_r_[PADR_(int)];
 	char semnum_l_[PADL_(int)]; int semnum; char semnum_r_[PADR_(int)];
 	char cmd_l_[PADL_(int)]; int cmd; char cmd_r_[PADR_(int)];
-	char arg_l_[PADL_(union semun32 *)]; union semun32 * arg; char arg_r_[PADR_(union semun32 *)];
+	char arg_l_[PADL_(union semun_old32 *)]; union semun_old32 * arg; char arg_r_[PADR_(union semun_old32 *)];
 };
 struct freebsd7_freebsd32_msgctl_args {
 	char msqid_l_[PADL_(int)]; int msqid; char msqid_r_[PADR_(int)];
diff --git a/sys/compat/freebsd32/syscalls.master b/sys/compat/freebsd32/syscalls.master
index 81ed039a4195..d9feba7aef0e 100644
--- a/sys/compat/freebsd32/syscalls.master
+++ b/sys/compat/freebsd32/syscalls.master
@@ -420,7 +420,7 @@
 
 220	AUE_SEMCTL	COMPAT7|NOSTD	{ int freebsd32_semctl( \
 				    int semid, int semnum, \
-				    int cmd, union semun32 *arg); }
+				    int cmd, union semun_old32 *arg); }
 221	AUE_SEMGET	NOSTD|NOPROTO	{ int semget(key_t key, int nsems, \
 				    int semflg); }
 222	AUE_SEMOP	NOSTD|NOPROTO	{ int semop(int semid, \
diff --git a/sys/kern/sysv_sem.c b/sys/kern/sysv_sem.c
index dd8925246d1e..274226481fa7 100644
--- a/sys/kern/sysv_sem.c
+++ b/sys/kern/sysv_sem.c
@@ -1870,7 +1870,7 @@ freebsd7_freebsd32_semctl(struct thread *td,
 	struct semid_ds32_old dsbuf32;
 	struct semid_ds dsbuf;
 	union semun semun;
-	union semun32 arg;
+	union semun_old32 arg;
 	register_t rval;
 	int error;