diff --git a/sys/kern/init_sysent.c b/sys/kern/init_sysent.c
index 59a3e5e3e8f..0bd62906ae9 100644
--- a/sys/kern/init_sysent.c
+++ b/sys/kern/init_sysent.c
@@ -239,7 +239,7 @@ struct sysent sysent[] = {
 	{ 6, (sy_call_t *)__sysctl },			/* 202 = __sysctl */
 	{ 2, (sy_call_t *)mlock },			/* 203 = mlock */
 	{ 2, (sy_call_t *)munlock },			/* 204 = munlock */
-	{ 0, (sy_call_t *)nosys },			/* 205 = nosys */
+	{ 2, (sy_call_t *)utrace },			/* 205 = utrace */
 	{ 0, (sy_call_t *)nosys },			/* 206 = nosys */
 	{ 0, (sy_call_t *)nosys },			/* 207 = nosys */
 	{ 0, (sy_call_t *)nosys },			/* 208 = nosys */
diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c
index 46b1ca6b48d..595e4efb840 100644
--- a/sys/kern/kern_ktrace.c
+++ b/sys/kern/kern_ktrace.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_ktrace.c	8.2 (Berkeley) 9/23/93
- * $Id: kern_ktrace.c,v 1.11 1996/03/11 06:03:23 hsu Exp $
+ * $Id: kern_ktrace.c,v 1.12 1996/08/04 20:13:07 phk Exp $
  */
 
 #include "opt_ktrace.h"
@@ -346,6 +346,45 @@ done:
 #endif
 }
 
+/*
+ * utrace system call
+ */
+/* ARGSUSED */
+int
+utrace(curp, uap, retval)
+	struct proc *curp;
+	register struct utrace_args *uap;
+	int *retval;
+{
+#ifdef KTRACE
+	register struct ktr_user *ktp;
+	struct ktr_header *kth;
+	struct proc *p = curproc;	/* XXX */
+	register caddr_t cp;
+
+	if (!KTRPOINT(p, KTR_USER))
+		return (0);
+	p->p_traceflag |= KTRFAC_ACTIVE;
+	kth = ktrgetheader(KTR_USER);
+	MALLOC(ktp, struct ktr_user *, sizeof(struct ktr_user) + uap->len,
+		M_KTRACE, M_WAITOK);
+	ktp->len = uap->len;
+	cp = (caddr_t)((char *)ktp + sizeof (struct ktr_user));
+	if (!copyin(uap->addr, cp, uap->len)) {
+		kth->ktr_buf = (caddr_t)ktp;
+		kth->ktr_len = sizeof (struct ktr_user) + uap->len;
+		ktrwrite(p->p_tracep, kth);
+	}
+	FREE(kth, M_KTRACE);
+	FREE(ktp, M_KTRACE);
+	p->p_traceflag &= ~KTRFAC_ACTIVE;
+
+	return (0);
+#else
+	return (ENOSYS);
+#endif
+}
+
 #ifdef KTRACE
 static int
 ktrops(curp, p, ops, facs, vp)
diff --git a/sys/kern/syscalls.c b/sys/kern/syscalls.c
index ded3c53701b..fd06481974b 100644
--- a/sys/kern/syscalls.c
+++ b/sys/kern/syscalls.c
@@ -226,7 +226,7 @@ char *syscallnames[] = {
 	"__sysctl",			/* 202 = __sysctl */
 	"mlock",			/* 203 = mlock */
 	"munlock",			/* 204 = munlock */
-	"#205",			/* 205 = nosys */
+	"utrace",			/* 205 = utrace */
 	"#206",			/* 206 = nosys */
 	"#207",			/* 207 = nosys */
 	"#208",			/* 208 = nosys */
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index ad5ba53e1c4..c0c5f0fdbb5 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -1,4 +1,4 @@
-	$Id: syscalls.master,v 1.27 1996/03/02 16:51:25 peter Exp $
+	$Id: syscalls.master,v 1.28 1996/08/20 07:17:49 smpatel Exp $
 ;	from: @(#)syscalls.master	8.2 (Berkeley) 1/13/94
 ;
 ; System call name/number master file.
@@ -322,7 +322,7 @@
 ; here allows to avoid one in libc/sys/Makefile.inc.
 203	STD	BSD	{ int mlock(caddr_t addr, size_t len); }
 204	STD	BSD	{ int munlock(caddr_t addr, size_t len); }
-205	UNIMPL	NOHIDE	nosys
+205	STD	BSD	{ int utrace(caddr_t addr, size_t len); }
 206	UNIMPL	NOHIDE	nosys
 207	UNIMPL	NOHIDE	nosys
 208	UNIMPL	NOHIDE	nosys
diff --git a/sys/sys/ktrace.h b/sys/sys/ktrace.h
index 6ae1af3dfba..15b155a6d5a 100644
--- a/sys/sys/ktrace.h
+++ b/sys/sys/ktrace.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ktrace.h	8.1 (Berkeley) 6/2/93
- * $Id: ktrace.h,v 1.7 1995/03/16 18:16:19 bde Exp $
+ * $Id: ktrace.h,v 1.8 1995/12/14 08:32:31 phk Exp $
  */
 
 #ifndef _SYS_KTRACE_H_
@@ -132,6 +132,17 @@ struct ktr_csw {
 	int	user;	/* 1 if usermode (ivcsw), 0 if kernel (vcsw) */
 };
 
+/*
+ * KTR_USER - data comming from userland
+ */
+#define KTR_USER	7
+struct ktr_user {
+	int	len;	/* number of bytes */
+	/*
+	 * followed by data provided by user
+	 */
+};
+
 /*
  * kernel trace points (in p_traceflag)
  */
@@ -142,6 +153,7 @@ struct ktr_csw {
 #define KTRFAC_GENIO	(1<<KTR_GENIO)
 #define	KTRFAC_PSIG	(1<<KTR_PSIG)
 #define KTRFAC_CSW	(1<<KTR_CSW)
+#define KTRFAC_USER	(1<<KTR_USER)
 /*
  * trace flags (also in p_traceflags)
  */
@@ -163,6 +175,7 @@ void	ktrsysret __P((struct vnode *, int, int, int));
 
 __BEGIN_DECLS
 int	ktrace __P((const char *, int, int, pid_t));
+int	utrace __P((const caddr_t , size_t));
 __END_DECLS
 
 #endif	/* !KERNEL */
diff --git a/sys/sys/syscall-hide.h b/sys/sys/syscall-hide.h
index 7ae407a6179..cb41f53c0a1 100644
--- a/sys/sys/syscall-hide.h
+++ b/sys/sys/syscall-hide.h
@@ -196,6 +196,7 @@ HIDE_BSD(ftruncate)
 HIDE_BSD(__sysctl)
 HIDE_BSD(mlock)
 HIDE_BSD(munlock)
+HIDE_BSD(utrace)
 HIDE_BSD(__semctl)
 HIDE_BSD(semget)
 HIDE_BSD(semop)
diff --git a/sys/sys/syscall.h b/sys/sys/syscall.h
index 0759e7ab09d..2ee6553d302 100644
--- a/sys/sys/syscall.h
+++ b/sys/sys/syscall.h
@@ -190,6 +190,7 @@
 #define	SYS___sysctl	202
 #define	SYS_mlock	203
 #define	SYS_munlock	204
+#define	SYS_utrace	205
 #define	SYS___semctl	220
 #define	SYS_semget	221
 #define	SYS_semop	222
diff --git a/sys/sys/sysproto.h b/sys/sys/sysproto.h
index 4aba14dc966..bb7f136b83c 100644
--- a/sys/sys/sysproto.h
+++ b/sys/sys/sysproto.h
@@ -653,6 +653,10 @@ struct	munlock_args {
 	caddr_t addr;
 	size_t len;
 };
+struct	utrace_args {
+	caddr_t addr;
+	size_t len;
+};
 struct	__semctl_args {
 	int semid;
 	int semnum;
@@ -873,6 +877,7 @@ int	ftruncate __P((struct proc *, struct ftruncate_args *, int []));
 int	__sysctl __P((struct proc *, struct sysctl_args *, int []));
 int	mlock __P((struct proc *, struct mlock_args *, int []));
 int	munlock __P((struct proc *, struct munlock_args *, int []));
+int	utrace __P((struct proc *, struct utrace_args *, int []));
 int	lkmnosys __P((struct proc *, struct nosys_args *, int []));
 int	__semctl __P((struct proc *, struct __semctl_args *, int []));
 int	semget __P((struct proc *, struct semget_args *, int []));