diff --git a/include/minix/com.h b/include/minix/com.h
index 67bc7a1f1..d571f2a3c 100644
--- a/include/minix/com.h
+++ b/include/minix/com.h
@@ -830,22 +830,10 @@
 #define IPC_SHMAT	(IPC_BASE+2)
 #define IPC_SHMDT	(IPC_BASE+3)
 #define IPC_SHMCTL	(IPC_BASE+4)
-#	define SHMCTL_ID	m2_i1
-#	define SHMCTL_CMD	m2_i2
-#	define SHMCTL_BUF	m2_l1
-#	define SHMCTL_RET	m2_i3
 
 /* Semaphore */
 #define IPC_SEMGET	(IPC_BASE+5)
-#	define SEMGET_KEY	m2_l1
-#	define SEMGET_NR	m2_i1
-#	define SEMGET_FLAG	m2_i2
-#	define SEMGET_RETID	m2_i3
 #define IPC_SEMCTL	(IPC_BASE+6)
-#	define SEMCTL_ID	m2_i1
-#	define SEMCTL_NUM	m2_i2
-#	define SEMCTL_CMD	m2_i3
-#	define SEMCTL_OPT	m2_l1
 #define IPC_SEMOP	(IPC_BASE+7)
 #	define SEMOP_ID		m2_i1
 #	define SEMOP_OPS	m2_l1
diff --git a/include/minix/ipc.h b/include/minix/ipc.h
index 374da5358..328eab4ca 100644
--- a/include/minix/ipc.h
+++ b/include/minix/ipc.h
@@ -1789,6 +1789,34 @@ typedef struct {
 } mess_lc_ipc_shmdt;
 _ASSERT_MSG_SIZE(mess_lc_ipc_shmdt);
 
+typedef struct {
+	int		id;
+	int		cmd;
+	void		*buf;
+	int		ret;
+	uint8_t		padding[40];
+} mess_lc_ipc_shmctl;
+_ASSERT_MSG_SIZE(mess_lc_ipc_shmctl);
+
+typedef struct {
+	key_t		key;
+	int		nr;
+	int		flag;
+	int		retid;
+	uint8_t		padding[40];
+} mess_lc_ipc_semget;
+_ASSERT_MSG_SIZE(mess_lc_ipc_semget);
+
+typedef struct {
+	int		id;
+	int		num;
+	int		cmd;
+	int		opt;
+	int		ret;
+	uint8_t		padding[36];
+} mess_lc_ipc_semctl;
+_ASSERT_MSG_SIZE(mess_lc_ipc_semctl);
+
 typedef struct {
 	endpoint_t m_source;		/* who sent the message */
 	int m_type;			/* what kind of message is it */
@@ -2018,6 +2046,9 @@ typedef struct {
 		mess_lc_ipc_shmget	m_lc_ipc_shmget;
 		mess_lc_ipc_shmat	m_lc_ipc_shmat;
 		mess_lc_ipc_shmdt	m_lc_ipc_shmdt;
+		mess_lc_ipc_shmctl	m_lc_ipc_shmctl;
+		mess_lc_ipc_semget	m_lc_ipc_semget;
+		mess_lc_ipc_semctl	m_lc_ipc_semctl;
 
 		mess_vfs_lchardriver_cancel	m_vfs_lchardriver_cancel;
 		mess_vfs_lchardriver_openclose	m_vfs_lchardriver_openclose;
diff --git a/lib/libc/sys-minix/sem.c b/lib/libc/sys-minix/sem.c
index de8ba6c7f..37d3b3e66 100644
--- a/lib/libc/sys-minix/sem.c
+++ b/lib/libc/sys-minix/sem.c
@@ -35,15 +35,15 @@ int semget(key_t key, int nsems, int semflag)
 	}
 
 	memset(&m, 0, sizeof(m));
-	m.SEMGET_KEY = key;
-	m.SEMGET_NR = nsems;
-	m.SEMGET_FLAG = semflag;
+	m.m_lc_ipc_semget.key = key;
+	m.m_lc_ipc_semget.nr = nsems;
+	m.m_lc_ipc_semget.flag = semflag;
 
 	r = _syscall(ipc_pt, IPC_SEMGET, &m);
 	if (r != OK)
 		return r;
 
-	return m.SEMGET_RETID;
+	return m.m_lc_ipc_semget.retid;
 }
  
 /* Semaphore control operation.  */
@@ -60,21 +60,21 @@ int semctl(int semid, int semnum, int cmd, ...)
 	}
 
 	memset(&m, 0, sizeof(m));
-	m.SEMCTL_ID = semid;
-	m.SEMCTL_NUM = semnum;
-	m.SEMCTL_CMD = cmd;
+	m.m_lc_ipc_semctl.id = semid;
+	m.m_lc_ipc_semctl.num = semnum;
+	m.m_lc_ipc_semctl.cmd = cmd;
 	va_start(ap, cmd);
 	if (cmd == IPC_STAT || cmd == IPC_SET || cmd == IPC_INFO ||
 		cmd == SEM_INFO || cmd == SEM_STAT || cmd == GETALL ||
 		cmd == SETALL || cmd == SETVAL)
-		m.SEMCTL_OPT = (long) va_arg(ap, long);
+		m.m_lc_ipc_semctl.opt = (long) va_arg(ap, long);
 	va_end(ap); 
 
 	r = _syscall(ipc_pt, IPC_SEMCTL, &m);
 	if ((r != -1) && (cmd == GETNCNT || cmd == GETZCNT || cmd == GETPID ||
 		cmd == GETVAL || cmd == IPC_INFO || cmd == SEM_INFO ||
 		cmd == SEM_STAT))
-		return m.SHMCTL_RET;
+		return m.m_lc_ipc_semctl.ret;
 	return r;
 }
 
diff --git a/lib/libc/sys-minix/shmctl.c b/lib/libc/sys-minix/shmctl.c
index e3d10e760..9612e65a5 100644
--- a/lib/libc/sys-minix/shmctl.c
+++ b/lib/libc/sys-minix/shmctl.c
@@ -32,14 +32,14 @@ int shmctl(int shmid, int cmd, struct shmid_ds *buf)
 	}
 
 	memset(&m, 0, sizeof(m));
-	m.SHMCTL_ID = shmid;
-	m.SHMCTL_CMD = cmd;
-	m.SHMCTL_BUF = (long) buf;
+	m.m_lc_ipc_shmctl.id = shmid;
+	m.m_lc_ipc_shmctl.cmd = cmd;
+	m.m_lc_ipc_shmctl.buf = buf;
 
 	r = _syscall(ipc_pt, IPC_SHMCTL, &m);
 	if ((cmd == IPC_INFO || cmd == SHM_INFO || cmd == SHM_STAT)
 		&& (r == OK))
-		return m.SHMCTL_RET;
+		return m.m_lc_ipc_shmctl.ret;
 	return r;
 }
 
diff --git a/servers/ipc/sem.c b/servers/ipc/sem.c
index 558d35888..1b37894ed 100644
--- a/servers/ipc/sem.c
+++ b/servers/ipc/sem.c
@@ -57,9 +57,9 @@ int do_semget(message *m)
 	int nsems, flag, id;
 	struct sem_struct *sem;
 
-	key = m->SEMGET_KEY;
-	nsems = m->SEMGET_NR;
-	flag = m->SEMGET_FLAG;
+	key = m->m_lc_ipc_semget.key;
+	nsems = m->m_lc_ipc_semget.nr;
+	flag = m->m_lc_ipc_semget.flag;
 
 	if ((sem = sem_find_key(key))) {
 		if ((flag & IPC_CREAT) && (flag & IPC_EXCL))
@@ -94,7 +94,7 @@ int do_semget(message *m)
 		sem_list_nr++;
 	}
 
-	m->SEMGET_RETID = id;
+	m->m_lc_ipc_semget.retid = id;
 	return OK;
 }
 
@@ -287,14 +287,14 @@ int do_semctl(message *m)
 	struct semid_ds *ds, tmp_ds;
 	struct sem_struct *sem;
 
-	id = m->SEMCTL_ID;
-	num = m->SEMCTL_NUM;
-	cmd = m->SEMCTL_CMD;
+	id = m->m_lc_ipc_semctl.id;
+	num = m->m_lc_ipc_semctl.num;
+	cmd = m->m_lc_ipc_semctl.cmd;
 
 	if (cmd == IPC_STAT || cmd == IPC_SET || cmd == IPC_INFO ||
 		cmd == SEM_INFO || cmd == SEM_STAT || cmd == GETALL ||
 		cmd == SETALL || cmd == SETVAL)
-		opt = m->SEMCTL_OPT;
+		opt = m->m_lc_ipc_semctl.opt;
 
 	if (!(sem = sem_find_id(id))) {
 		return EINVAL;
@@ -367,22 +367,22 @@ int do_semctl(message *m)
 	case GETNCNT:
 		if (num < 0 || num >= sem->semid_ds.sem_nsems)
 			return EINVAL;
-		m->SHMCTL_RET = sem->sems[num].semncnt;
+		m->m_lc_ipc_semctl.ret = sem->sems[num].semncnt;
 		break;
 	case GETPID:
 		if (num < 0 || num >= sem->semid_ds.sem_nsems)
 			return EINVAL;
-		m->SHMCTL_RET = sem->sems[num].sempid;
+		m->m_lc_ipc_semctl.ret = sem->sems[num].sempid;
 		break;
 	case GETVAL:
 		if (num < 0 || num >= sem->semid_ds.sem_nsems)
 			return EINVAL;
-		m->SHMCTL_RET = sem->sems[num].semval;
+		m->m_lc_ipc_semctl.ret = sem->sems[num].semval;
 		break;
 	case GETZCNT:
 		if (num < 0 || num >= sem->semid_ds.sem_nsems)
 			return EINVAL;
-		m->SHMCTL_RET = sem->sems[num].semzcnt;
+		m->m_lc_ipc_semctl.ret = sem->sems[num].semzcnt;
 		break;
 	case SETALL:
 		buf = malloc(sizeof(unsigned short) * sem->semid_ds.sem_nsems);
diff --git a/servers/ipc/shm.c b/servers/ipc/shm.c
index da90a9cbd..3ce9568db 100644
--- a/servers/ipc/shm.c
+++ b/servers/ipc/shm.c
@@ -217,9 +217,9 @@ int do_shmdt(message *m)
  *===========================================================================*/
 int do_shmctl(message *m)
 {
-	int id = m->SHMCTL_ID;
-	int cmd = m->SHMCTL_CMD;
-	struct shmid_ds *ds = (struct shmid_ds *)m->SHMCTL_BUF;
+	int id = m->m_lc_ipc_shmctl.id;
+	int cmd = m->m_lc_ipc_shmctl.cmd;
+	struct shmid_ds *ds = (struct shmid_ds *)m->m_lc_ipc_shmctl.buf;
 	struct shmid_ds tmp_ds;
 	struct shm_struct *shm = NULL;
 	struct shminfo sinfo;
@@ -286,9 +286,9 @@ int do_shmctl(message *m)
 			who_e, (vir_bytes)ds, sizeof(struct shminfo));
 		if (r != OK)
 			return EFAULT;
-		m->SHMCTL_RET = shm_list_nr - 1;
-		if (m->SHMCTL_RET < 0)
-			m->SHMCTL_RET = 0;
+		m->m_lc_ipc_shmctl.ret = (shm_list_nr - 1);
+		if (m->m_lc_ipc_shmctl.ret < 0)
+			m->m_lc_ipc_shmctl.ret = 0;
 		break;
 	case SHM_INFO:
 		if (!ds)
@@ -306,9 +306,9 @@ int do_shmctl(message *m)
 			who_e, (vir_bytes)ds, sizeof(struct shm_info));
 		if (r != OK)
 			return EFAULT;
-		m->SHMCTL_RET = shm_list_nr - 1;
-		if (m->SHMCTL_RET < 0)
-			m->SHMCTL_RET = 0;
+		m->m_lc_ipc_shmctl.ret = shm_list_nr - 1;
+		if (m->m_lc_ipc_shmctl.ret < 0)
+			m->m_lc_ipc_shmctl.ret = 0;
 		break;
 	case SHM_STAT:
 		if (id < 0 || id >= shm_list_nr)
@@ -318,7 +318,7 @@ int do_shmctl(message *m)
 			who_e, (vir_bytes)ds, sizeof(struct shmid_ds));
 		if (r != OK)
 			return EFAULT;
-		m->SHMCTL_RET = shm->id;
+		m->m_lc_ipc_shmctl.ret = shm->id;
 		break;
 	default:
 		return EINVAL;