diff --git a/include/minix/com.h b/include/minix/com.h
index 463ded22c..0ea6126e9 100644
--- a/include/minix/com.h
+++ b/include/minix/com.h
@@ -470,14 +470,6 @@
 #define SG_ADDR		m2_p1	/* address */
 #define SG_SIZE		m2_i2	/* no. of entries */
 
-/* Field names for SYS_GETKSIG, _ENDKSIG, _KILL, _SIGSEND, _SIGRETURN. */
-#define SYS_SIG_ENDPT      m_sigcalls.ep     /* process number for inform */
-#define SYS_SIG_NUMBER     m_sigcalls.sig    /* signal number to send */
-#define SYS_SIG_FLAGS      m_sigcalls.flags  /* signal flags field */
-#define SYS_SIG_MAP        m_sigcalls.sigs   /* used to pass signal bit map */
-#define SYS_SIG_CTXT_PTR   m_sigcalls.sigctx /* pointer to signal context */
-#define SYS_SIG_HOW        m_sigcalls.how   /* used to pass signal bit map */
-
 /* Field names for SYS_FORK, _EXEC, _EXIT, GETMCONTEXT, SETMCONTEXT.*/
 #define PR_ENDPT        m1_i1	/* indicates a process */
 #define PR_PRIORITY     m1_i2	/* process priority */
diff --git a/include/minix/ipc.h b/include/minix/ipc.h
index 9213e323e..6eae8bfa4 100644
--- a/include/minix/ipc.h
+++ b/include/minix/ipc.h
@@ -35,17 +35,6 @@ typedef struct {
 } mess_2;
 _ASSERT_MSG_SIZE(mess_2);
 
-typedef struct {
-	endpoint_t ep;
-	int sig;
-	u32_t flags;
-	sigset_t sigs;
-	void *sigctx;
-	int how;
-	uint8_t padding[20];
-} mess_sigcalls;
-_ASSERT_MSG_SIZE(mess_sigcalls);
-
 typedef struct {
 	int m3i1, m3i2;
 	char *m3p1;
@@ -135,6 +124,16 @@ typedef struct {
 } mess_notify;
 _ASSERT_MSG_SIZE(mess_notify);
 
+/* For SYS_GETKSIG, _ENDKSIG, _KILL, _SIGSEND, _SIGRETURN. */
+typedef struct {
+	sigset_t map;		/* used to pass signal bit map */
+	endpoint_t endpt;	/* process number for inform */
+	int sig;		/* signal number to send */
+	void *sigctx;		/* pointer to signal context */
+	uint8_t padding[28];
+} mess_sigcalls;
+_ASSERT_MSG_SIZE(mess_sigcalls);
+
 typedef struct {
 	off_t offset;
 	dev_t dev;
@@ -186,10 +185,10 @@ typedef struct {
 	mess_11 m_m11;
 	mess_mmap m_mmap;
 	mess_notify m_notify;
+	mess_sigcalls m_sigcalls;
 	mess_vm_vfs_mmap m_vm_vfs_mmap;
 	mess_vmmcp m_vmmcp;
 	mess_vmmcp_reply m_vmmcp_reply;
-	mess_sigcalls m_sigcalls; /* SYS_{GETKSIG,ENDKSIG,KILL,SIGSEND,SIGRETURN} */
 	u8_t size[56];		/* message payload may have 56 bytes at most */
   };
 } message __aligned(16);
diff --git a/kernel/system/do_endksig.c b/kernel/system/do_endksig.c
index 414e01179..eac6a3e70 100644
--- a/kernel/system/do_endksig.c
+++ b/kernel/system/do_endksig.c
@@ -1,8 +1,8 @@
 /* The kernel call that is implemented in this file:
- *   m_type:	SYS_ENDKSIG
+ *	m_type: SYS_ENDKSIG
  *
  * The parameters for this kernel call are:
- *     m2_i1:	SIG_ENDPT  	# process for which PM is done
+ *	m_sigcalls.endpt	# process for which PM is done
  */
 
 #include "kernel/system.h"
@@ -24,7 +24,7 @@ int do_endksig(struct proc * caller, message * m_ptr)
   /* Get process pointer and verify that it had signals pending. If the 
    * process is already dead its flags will be reset. 
    */
-  if(!isokendpt(m_ptr->SYS_SIG_ENDPT, &proc_nr))
+  if(!isokendpt(m_ptr->m_sigcalls.endpt, &proc_nr))
 	return EINVAL;
 
   rp = proc_addr(proc_nr);
diff --git a/kernel/system/do_getksig.c b/kernel/system/do_getksig.c
index 496066f91..a8b5e7dc9 100644
--- a/kernel/system/do_getksig.c
+++ b/kernel/system/do_getksig.c
@@ -1,9 +1,9 @@
 /* The kernel call that is implemented in this file:
- *   m_type:	SYS_GETKSIG
+ *	m_type: SYS_GETKSIG
  *
  * The parameters for this kernel call are:
- *     m2_i1:	SYS_SIG_ENDPT  	# process with pending signals
- *     m2_l1:	SYS_SIG_MAP		# bit map with pending signals
+ *	m_sigcalls.endpt	# process with pending signals
+ *	m_sigcalls.map		# bit map with pending signals
  */
 
 #include "kernel/system.h"
@@ -28,8 +28,8 @@ int do_getksig(struct proc * caller, message * m_ptr)
       if (RTS_ISSET(rp, RTS_SIGNALED)) {
           if (caller->p_endpoint != priv(rp)->s_sig_mgr) continue;
 	  /* store signaled process' endpoint */
-          m_ptr->SYS_SIG_ENDPT = rp->p_endpoint;
-          m_ptr->SYS_SIG_MAP = rp->p_pending;	/* pending signals map */
+          m_ptr->m_sigcalls.endpt = rp->p_endpoint;
+          m_ptr->m_sigcalls.map = rp->p_pending;	/* pending signals map */
           (void) sigemptyset(&rp->p_pending); 	/* clear map in the kernel */
 	  RTS_UNSET(rp, RTS_SIGNALED);		/* blocked by SIG_PENDING */
           return(OK);
@@ -37,8 +37,7 @@ int do_getksig(struct proc * caller, message * m_ptr)
   }
 
   /* No process with pending signals was found. */
-  m_ptr->SYS_SIG_ENDPT = NONE; 
+  m_ptr->m_sigcalls.endpt = NONE;
   return(OK);
 }
 #endif /* USE_GETKSIG */
-
diff --git a/kernel/system/do_kill.c b/kernel/system/do_kill.c
index 7bc4a9568..b3e22f735 100644
--- a/kernel/system/do_kill.c
+++ b/kernel/system/do_kill.c
@@ -1,9 +1,9 @@
 /* The kernel call that is implemented in this file:
- *   m_type:	SYS_KILL
+ *	m_type: SYS_KILL
  *
  * The parameters for this kernel call are:
- *     m2_i1:	SYS_SIG_ENDPT  	# process to signal/ pending		
- *     m2_i2:	SYS_SIG_NUMBER	# signal number to send to process
+ *	m_sigcalls.endpt  	# process to signal/ pending
+ *	m_sigcalls.sig		# signal number to send to process
  */
 
 #include "kernel/system.h"
@@ -23,9 +23,9 @@ int do_kill(struct proc * caller, message * m_ptr)
  * translated into an IPC message for system services.
  */
   proc_nr_t proc_nr, proc_nr_e;
-  int sig_nr = m_ptr->SYS_SIG_NUMBER;
+  int sig_nr = m_ptr->m_sigcalls.sig;
 
-  proc_nr_e= (proc_nr_t) m_ptr->SYS_SIG_ENDPT;
+  proc_nr_e = (proc_nr_t)m_ptr->m_sigcalls.endpt;
 
   if (!isokendpt(proc_nr_e, &proc_nr)) return(EINVAL);
   if (sig_nr >= _NSIG) return(EINVAL);
diff --git a/kernel/system/do_sigreturn.c b/kernel/system/do_sigreturn.c
index 833010733..09fc7d65d 100644
--- a/kernel/system/do_sigreturn.c
+++ b/kernel/system/do_sigreturn.c
@@ -1,9 +1,9 @@
 /* The kernel call that is implemented in this file:
- *   m_type:	SYS_SIGRETURN
+ *	m_type: SYS_SIGRETURN
  *
  * The parameters for this kernel call are:
- *     m2_i1:	SIG_ENDPT  	# process returning from handler
- *     m2_p1:	SIG_CTXT_PTR 	# pointer to sigcontext structure
+ *	m_sigcalls.endp		# process returning from handler
+ *	m_sigcalls.sigctx	# pointer to sigcontext structure
  *
  */
 
@@ -25,13 +25,14 @@ int do_sigreturn(struct proc * caller, message * m_ptr)
   register struct proc *rp;
   int proc_nr, r;
 
-  if (! isokendpt(m_ptr->SYS_SIG_ENDPT, &proc_nr)) return(EINVAL);
-  if (iskerneln(proc_nr)) return(EPERM);
+  if (!isokendpt(m_ptr->m_sigcalls.endpt, &proc_nr)) return EINVAL;
+  if (iskerneln(proc_nr)) return EPERM;
   rp = proc_addr(proc_nr);
 
   /* Copy in the sigcontext structure. */
-  if((r=data_copy(m_ptr->SYS_SIG_ENDPT, (vir_bytes) m_ptr->SYS_SIG_CTXT_PTR,
-	KERNEL, (vir_bytes) &sc, sizeof(struct sigcontext))) != OK)
+  if ((r = data_copy(m_ptr->m_sigcalls.endpt,
+		 (vir_bytes)m_ptr->m_sigcalls.sigctx, KERNEL,
+		 (vir_bytes)&sc, sizeof(struct sigcontext))) != OK)
 	return r;
 
 #if defined(__i386__)
@@ -53,7 +54,7 @@ int do_sigreturn(struct proc * caller, message * m_ptr)
   /* Restore the registers. */
   arch_proc_setcontext(rp, &sc.sc_regs, 1, sc.trap_style);
 #if defined(__i386__)
-  if(sc.sc_flags & MF_FPU_INITIALIZED)
+  if (sc.sc_flags & MF_FPU_INITIALIZED)
   {
 	memcpy(rp->p_seg.fpu_state, &sc.sc_fpu_state, FPU_XFP_SIZE);
 	rp->p_misc_flags |=  MF_FPU_INITIALIZED; /* Restore math usage flag. */
@@ -62,7 +63,7 @@ int do_sigreturn(struct proc * caller, message * m_ptr)
   }
 #endif
 
-  return(OK);
+  return OK;
 }
 #endif /* USE_SIGRETURN */
 
diff --git a/kernel/system/do_sigsend.c b/kernel/system/do_sigsend.c
index 95f46e3e1..430a2b083 100644
--- a/kernel/system/do_sigsend.c
+++ b/kernel/system/do_sigsend.c
@@ -1,10 +1,9 @@
 /* The kernel call that is implemented in this file:
- *   m_type:	SYS_SIGSEND
+ *	m_type: SYS_SIGSEND
  *
  * The parameters for this kernel call are:
- *     m2_i1:	SYS_SIG_ENDPT  	# process to call signal handler
- *     m2_p1:	SYS_SIG_CTXT_PTR 	# pointer to sigcontext structure
- *     m2_i3:	SYS_SIG_FLAGS    	# flags for S_SIGRETURN call	
+ * 	m_sigcalls.endpt	# process to call signal handler
+ *	m_sigcalls.sigctx	# pointer to sigcontext structure
  *
  */
 
@@ -27,14 +26,14 @@ int do_sigsend(struct proc * caller, message * m_ptr)
   struct sigframe fr, *frp;
   int proc_nr, r;
 
-  if (!isokendpt(m_ptr->SYS_SIG_ENDPT, &proc_nr)) return(EINVAL);
-  if (iskerneln(proc_nr)) return(EPERM);
+  if (!isokendpt(m_ptr->m_sigcalls.endpt, &proc_nr)) return EINVAL;
+  if (iskerneln(proc_nr)) return EPERM;
   rp = proc_addr(proc_nr);
 
   /* Get the sigmsg structure into our address space.  */
-  if((r=data_copy_vmcheck(caller, caller->p_endpoint,
-		(vir_bytes) m_ptr->SYS_SIG_CTXT_PTR, KERNEL, (vir_bytes) &smsg,
-		(phys_bytes) sizeof(struct sigmsg))) != OK)
+  if ((r = data_copy_vmcheck(caller, caller->p_endpoint,
+		(vir_bytes)m_ptr->m_sigcalls.sigctx, KERNEL,
+		(vir_bytes)&smsg, (phys_bytes) sizeof(struct sigmsg))) != OK)
 	return r;
 
   /* Compute the user stack pointer where sigcontext will be stored. */
@@ -47,12 +46,12 @@ int do_sigsend(struct proc * caller, message * m_ptr)
 #if defined(__i386__)
   sc.trap_style = rp->p_seg.p_kern_trap_style;
 
-  if(sc.trap_style == KTS_NONE) {
+  if (sc.trap_style == KTS_NONE) {
   	printf("do_sigsend: sigsend an unsaved process\n");
 	return EINVAL;
   }
 
-    if(proc_used_fpu(rp)) {
+    if (proc_used_fpu(rp)) {
 	    /* save the FPU context before saving it to the sig context */
 	    save_fpu(rp);
 	    memcpy(&sc.sc_fpu_state, rp->p_seg.fpu_state, FPU_XFP_SIZE);
@@ -64,8 +63,9 @@ int do_sigsend(struct proc * caller, message * m_ptr)
   sc.sc_flags = rp->p_misc_flags & MF_FPU_INITIALIZED;
 
   /* Copy the sigcontext structure to the user's stack. */
-  if((r=data_copy_vmcheck(caller, KERNEL, (vir_bytes) &sc, m_ptr->SYS_SIG_ENDPT,
-	(vir_bytes) scp, (vir_bytes) sizeof(struct sigcontext))) != OK)
+  if ((r = data_copy_vmcheck(caller, KERNEL, (vir_bytes)&sc,
+		m_ptr->m_sigcalls.endpt, (vir_bytes)scp,
+		(vir_bytes)sizeof(struct sigcontext))) != OK)
       return r;
 
   /* Initialize the sigframe structure. */
@@ -96,9 +96,9 @@ int do_sigsend(struct proc * caller, message * m_ptr)
 #endif
 
   /* Copy the sigframe structure to the user's stack. */
-  if((r=data_copy_vmcheck(caller, KERNEL, (vir_bytes) &fr,
-	m_ptr->SYS_SIG_ENDPT, (vir_bytes) frp, 
-      (vir_bytes) sizeof(struct sigframe))) != OK)
+  if ((r = data_copy_vmcheck(caller, KERNEL, (vir_bytes)&fr,
+		m_ptr->m_sigcalls.endpt, (vir_bytes)frp,
+		(vir_bytes)sizeof(struct sigframe))) != OK)
       return r;
 
   /* Reset user registers to execute the signal handler. */
@@ -114,7 +114,7 @@ int do_sigsend(struct proc * caller, message * m_ptr)
 	proc_stacktrace(caller);
   }
 
-  return(OK);
+  return OK;
 }
 
 #endif /* USE_SIGSEND */
diff --git a/lib/libsys/sys_endsig.c b/lib/libsys/sys_endsig.c
index a93fe0c04..aa789febd 100644
--- a/lib/libsys/sys_endsig.c
+++ b/lib/libsys/sys_endsig.c
@@ -9,7 +9,7 @@ endpoint_t proc_ep;				/* process number */
     message m;
     int result;
 
-    m.SYS_SIG_ENDPT = proc_ep;
+    m.m_sigcalls.endpt = proc_ep;
     result = _kernel_call(SYS_ENDKSIG, &m);
     return(result);
 }
diff --git a/lib/libsys/sys_getsig.c b/lib/libsys/sys_getsig.c
index 30e335a33..cef42ced4 100644
--- a/lib/libsys/sys_getsig.c
+++ b/lib/libsys/sys_getsig.c
@@ -11,8 +11,8 @@ sigset_t *k_sig_map;			/* return signal map here */
     int result;
 
     result = _kernel_call(SYS_GETKSIG, &m);
-    *proc_ep = m.SYS_SIG_ENDPT;
-    *k_sig_map = m.SYS_SIG_MAP;
+    *proc_ep = m.m_sigcalls.endpt;
+    *k_sig_map = m.m_sigcalls.map;
     return(result);
 }
 
diff --git a/lib/libsys/sys_kill.c b/lib/libsys/sys_kill.c
index 7886c47ef..72a7f0b65 100644
--- a/lib/libsys/sys_kill.c
+++ b/lib/libsys/sys_kill.c
@@ -7,8 +7,8 @@ int signr;			/* signal number: 1 - 16 */
 /* A proc_ep has to be signaled via PM.  Tell the kernel. */
   message m;
 
-  m.SYS_SIG_ENDPT = proc_ep;
-  m.SYS_SIG_NUMBER = signr;
+  m.m_sigcalls.endpt = proc_ep;
+  m.m_sigcalls.sig = signr;
   return(_kernel_call(SYS_KILL, &m));
 }
 
diff --git a/lib/libsys/sys_sigreturn.c b/lib/libsys/sys_sigreturn.c
index 15ed38a4c..aa15786f6 100644
--- a/lib/libsys/sys_sigreturn.c
+++ b/lib/libsys/sys_sigreturn.c
@@ -10,8 +10,8 @@ struct sigmsg *sig_ctxt;		/* POSIX style handling */
     message m;
     int result;
 
-    m.SYS_SIG_ENDPT = proc_ep;
-    m.SYS_SIG_CTXT_PTR = (char *) sig_ctxt;
+    m.m_sigcalls.endpt = proc_ep;
+    m.m_sigcalls.sigctx = sig_ctxt;
     result = _kernel_call(SYS_SIGRETURN, &m);
     return(result);
 }
diff --git a/lib/libsys/sys_sigsend.c b/lib/libsys/sys_sigsend.c
index 2d0eae933..47efc2fb1 100644
--- a/lib/libsys/sys_sigsend.c
+++ b/lib/libsys/sys_sigsend.c
@@ -10,8 +10,8 @@ struct sigmsg *sig_ctxt;		/* POSIX style handling */
     message m;
     int result;
 
-    m.SYS_SIG_ENDPT = proc_ep;
-    m.SYS_SIG_CTXT_PTR = (char *) sig_ctxt;
+    m.m_sigcalls.endpt = proc_ep;
+    m.m_sigcalls.sigctx = sig_ctxt;
     result = _kernel_call(SYS_SIGSEND, &m);
     return(result);
 }