Move the common bits of syscall invocation and return handling into

an MI file, <sys/syscall_mi.h>, correcting inconsistencies and the
handling when copyin() of arguments fails.

Tested on i386, amd64, sparc64, and alpha (thanks naddy@)
Any issues with other platforms will be fixed in tree.

header name from millert@; ok miod@

20 files changed, 366 insertions, 913 deletions

diff --git a/sys/arch/alpha/alpha/trap.c b/sys/arch/alpha/alpha/trap.c
index b6c4bf00b24..2963ebf0a25 100644
--- a/sys/arch/alpha/alpha/trap.c
+++ b/sys/arch/alpha/alpha/trap.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: trap.c,v 1.60 2012/04/11 14:38:55 mikeb Exp $ */
+/* $OpenBSD: trap.c,v 1.61 2012/08/07 05:16:53 guenther Exp $ */
 /* $NetBSD: trap.c,v 1.52 2000/05/24 16:48:33 thorpej Exp $ */
 
 /*-
@@ -94,18 +94,13 @@
 #include <sys/signalvar.h>
 #include <sys/user.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/buf.h>
 #ifndef NO_IEEE
 #include <sys/device.h>
 #endif
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
 #include <sys/ptrace.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm_extern.h>
 
 #include <machine/cpu.h>
@@ -578,8 +573,9 @@ syscall(code, framep)
 	default:
 		if (nargs > 10)		/* XXX */
 			panic("syscall: too many args (%d)", nargs);
-		error = copyin((caddr_t)(alpha_pal_rdusp()), &args[6],
-		    (nargs - 6) * sizeof(u_long));
+		if ((error = copyin((caddr_t)(alpha_pal_rdusp()), &args[6],
+		    (nargs - 6) * sizeof(u_long))))
+			goto bad;
 	case 6:	
 		args[5] = framep->tf_regs[FRAME_A5];
 	case 5:	
@@ -595,23 +591,11 @@ syscall(code, framep)
 	case 0:
 		break;
 	}
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, callp->sy_argsize, args + hidden);
-#endif
-#ifdef SYSCALL_DEBUG
-	scdebug_call(p, code, args + hidden);
-#endif
-	if (error == 0) {
-		rval[0] = 0;
-		rval[1] = 0;
-#if NSYSTRACE > 0
-		if (ISSET(p->p_flag, P_SYSTRACE))
-			error = systrace_redirect(code, p, args + hidden, rval);
-		else
-#endif
-			error = (*callp->sy_call)(p, args + hidden, rval);
-	}
+
+	rval[0] = 0;
+	rval[1] = 0;
+
+	error = mi_syscall(p, code, callp, args + hidden, rval);
 
 	switch (error) {
 	case 0:
@@ -625,6 +609,7 @@ syscall(code, framep)
 	case EJUSTRETURN:
 		break;
 	default:
+	bad:
 		if (p->p_emul->e_errno)
 			error = p->p_emul->e_errno[error];
 		framep->tf_regs[FRAME_V0] = error;
@@ -632,17 +617,10 @@ syscall(code, framep)
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	scdebug_ret(p, code, error, rval);
-#endif
 	/* Do any deferred user pmap operations. */
 	PMAP_USERRET(vm_map_pmap(&p->p_vmspace->vm_map));
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, error, rval[0]);
-#endif
+	mi_syscall_return(p, code, error, rval);
 }
 
 /*
@@ -665,14 +643,7 @@ child_return(arg)
 	/* Do any deferred user pmap operations. */
 	PMAP_USERRET(vm_map_pmap(&p->p_vmspace->vm_map));
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-#endif
+	mi_child_return(p);
 }
 
 /*
diff --git a/sys/arch/amd64/amd64/trap.c b/sys/arch/amd64/amd64/trap.c
index 85c969834db..ec6445b6db4 100644
--- a/sys/arch/amd64/amd64/trap.c
+++ b/sys/arch/amd64/amd64/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.28 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.29 2012/08/07 05:16:53 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.2 2003/05/04 23:51:56 fvdl Exp $	*/
 
 /*-
@@ -77,13 +77,8 @@
 #include <sys/acct.h>
 #include <sys/kernel.h>
 #include <sys/signal.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
 #include <sys/syscall.h>
-
-#include "systrace.h"
-#include <dev/systrace.h>
+#include <sys/syscall_mi.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -494,7 +489,6 @@ syscall(struct trapframe *frame)
 	int nsys;
 	size_t argsize, argoff;
 	register_t code, args[9], rval[2], *argp;
-	int lock;
 
 	uvmexp.syscalls++;
 	p = curproc;
@@ -546,43 +540,16 @@ syscall(struct trapframe *frame)
 		if (argsize > 6) {
 			argsize -= 6;
 			params = (caddr_t)frame->tf_rsp + sizeof(register_t);
-			error = copyin(params, (caddr_t)&args[6],
-					argsize << 3);
-			if (error != 0)
+			if ((error = copyin(params, &args[6], argsize << 3)))
 				goto bad;
 		}
 	}
 
-	lock = !(callp->sy_flags & SY_NOLOCK);
-
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_call(p, code, argp);
-	KERNEL_UNLOCK();
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL)) {
-		KERNEL_LOCK();
-		ktrsyscall(p, code, callp->sy_argsize, argp);
-		KERNEL_UNLOCK();
-	}
-#endif
 	rval[0] = 0;
 	rval[1] = frame->tf_rdx;
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE)) {
-		KERNEL_LOCK();
-		error = systrace_redirect(code, p, argp, rval);
-		KERNEL_UNLOCK();
-	} else
-#endif
-	{
-		if (lock)
-			KERNEL_LOCK();
-		error = (*callp->sy_call)(p, argp, rval);
-		if (lock)
-			KERNEL_UNLOCK();
-	}
+
+	error = mi_syscall(p, code, callp, argp, rval);
+
 	switch (error) {
 	case 0:
 		frame->tf_rax = rval[0];
@@ -607,19 +574,7 @@ syscall(struct trapframe *frame)
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_ret(p, code, error, rval);
-	KERNEL_UNLOCK();
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p, code, error, rval[0]);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_syscall_return(p, code, error, rval);
 }
 
 void
@@ -634,15 +589,6 @@ child_return(void *arg)
 
 	KERNEL_UNLOCK();
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_child_return(p);
 }
+
diff --git a/sys/arch/arm/arm/syscall.c b/sys/arch/arm/arm/syscall.c
index 655139c521a..45ec8ebcfe5 100644
--- a/sys/arch/arm/arm/syscall.c
+++ b/sys/arch/arm/arm/syscall.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syscall.c,v 1.14 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: syscall.c,v 1.15 2012/08/07 05:16:53 guenther Exp $	*/
 /*	$NetBSD: syscall.c,v 1.24 2003/11/14 19:03:17 scw Exp $	*/
 
 /*-
@@ -78,15 +78,10 @@
 #include <sys/reboot.h>
 #include <sys/signalvar.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/systm.h>
 #include <sys/proc.h>
 #include <sys/user.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
-
-#include "systrace.h"
-#include <dev/systrace.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -102,7 +97,7 @@ swi_handler(trapframe_t *frame)
 {
 	struct proc *p = curproc;
 	const struct sysent *callp;
-	int code, error, orig_error;
+	int code, error;
 	u_int nap = 4, nargs;
 	register_t *ap, *args, copyargs[MAXARGS], rval[2];
 
@@ -139,33 +134,19 @@ swi_handler(trapframe_t *frame)
 	nargs = callp->sy_argsize / sizeof(register_t);
 	if (nargs <= nap) {
 		args = ap;
-		error = 0;
 	} else {
 		KASSERT(nargs <= MAXARGS);
 		memcpy(copyargs, ap, nap * sizeof(register_t));
-		error = copyin((void *)frame->tf_usr_sp, copyargs + nap,
-		    (nargs - nap) * sizeof(register_t));
+		if ((error = copyin((void *)frame->tf_usr_sp, copyargs + nap,
+		    (nargs - nap) * sizeof(register_t))))
+			goto bad;
 		args = copyargs;
 	}
-	orig_error = error;
-#ifdef SYSCALL_DEBUG
-        scdebug_call(p, code, args);
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, callp->sy_argsize, args);
-#endif
-	if (error)
-		goto bad;
 
 	rval[0] = 0;
 	rval[1] = frame->tf_r1;
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		orig_error = error = systrace_redirect(code, p, args, rval);
-	else 
-#endif
-		orig_error = error = (*callp->sy_call)(p, args, rval);
+
+	error = mi_syscall(p, code, callp, args, rval);
 
 	switch (error) {
 	case 0:
@@ -192,14 +173,8 @@ swi_handler(trapframe_t *frame)
 		frame->tf_spsr |= PSR_C_bit;	/* carry bit */
 		break;
 	}
-#ifdef SYSCALL_DEBUG
-	scdebug_ret(p, code, orig_error, rval);
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, orig_error, rval[0]);
-#endif
+
+	mi_syscall_return(p, code, error, rval);
 }
 
 void
@@ -212,14 +187,5 @@ child_return(arg)
 	frame->tf_r0 = 0;
 	frame->tf_spsr &= ~PSR_C_bit;	/* carry bit */
 
-	userret(p);
-
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-	}
-#endif
+	mi_child_return(p);
 }
diff --git a/sys/arch/hp300/hp300/trap.c b/sys/arch/hp300/hp300/trap.c
index d299aa6b140..79dd088277f 100644
--- a/sys/arch/hp300/hp300/trap.c
+++ b/sys/arch/hp300/hp300/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.60 2011/11/16 20:50:18 deraadt Exp $	*/
+/*	$OpenBSD: trap.c,v 1.61 2012/08/07 05:16:53 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.57 1998/02/16 20:58:31 thorpej Exp $	*/
 
 /*
@@ -70,11 +70,9 @@
 #include <sys/signalvar.h>
 #include <sys/resourcevar.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/syslog.h>
 #include <sys/user.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
 
 #include <m68k/frame.h>
 
@@ -85,9 +83,6 @@
 #include <machine/reg.h>
 #include <machine/intr.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm_extern.h>
 #include <uvm/uvm_pmap.h>
 
@@ -949,8 +944,8 @@ syscall(code, frame)
 		/*
 		 * Code is first argument, followed by actual args.
 		 */
-		if (copyin(params, &code, sizeof(register_t)) != 0)
-			code = -1;
+		if ((error = copyin(params, &code, sizeof(register_t))))
+			goto bad;
 		params += sizeof(int);
 		/*
 		 * XXX sigreturn requires special stack manipulation
@@ -967,9 +962,9 @@ syscall(code, frame)
 		 */
 		if (callp != sysent)
 			break;
-		if (copyin(params + _QUAD_LOWWORD * sizeof(int), &code,
-		    sizeof(register_t)) != 0)
-			code = -1;
+		if ((error = copyin(params + _QUAD_LOWWORD * sizeof(int),
+		    &code, sizeof(register_t))))
+			goto bad;
 		params += sizeof(quad_t);
 		break;
 	default:
@@ -980,27 +975,14 @@ syscall(code, frame)
 	else
 		callp += code;
 	argsize = callp->sy_argsize;
-	if (argsize)
-		error = copyin(params, (caddr_t)args, argsize);
-	else
-		error = 0;
-#ifdef SYSCALL_DEBUG
-	scdebug_call(p, code, args);
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, argsize, args);
-#endif
-	if (error)
+	if (argsize && (error = copyin(params, args, argsize)))
 		goto bad;
+
 	rval[0] = 0;
 	rval[1] = frame.f_regs[D1];
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		error = systrace_redirect(code, p, args, rval);
-	else
-#endif
-		error = (*callp->sy_call)(p, args, rval);
+
+	error = mi_syscall(p, code, callp, args, rval);
+
 	switch (error) {
 	case 0:
 		frame.f_regs[D0] = rval[0];
@@ -1018,7 +1000,7 @@ syscall(code, frame)
 		/* nothing to do */
 		break;
 	default:
-bad:
+	bad:
 		if (p->p_emul->e_errno)
 			error = p->p_emul->e_errno[error];
 		frame.f_regs[D0] = error;
@@ -1026,12 +1008,5 @@ bad:
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	scdebug_ret(p, code, error, rval);
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, error, rval[0]);
-#endif
+	mi_syscall_return(p, code, error, rval);
 }
diff --git a/sys/arch/hppa/hppa/trap.c b/sys/arch/hppa/hppa/trap.c
index 8ebf286f463..7da4b3f4532 100644
--- a/sys/arch/hppa/hppa/trap.c
+++ b/sys/arch/hppa/hppa/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.122 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.123 2012/08/07 05:16:53 guenther Exp $	*/
 
 /*
  * Copyright (c) 1998-2004 Michael Shalayeff
@@ -31,14 +31,12 @@
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/ktrace.h>
 #include <sys/proc.h>
 #include <sys/signalvar.h>
 #include <sys/user.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm.h>
 
 #include <machine/autoconf.h>
@@ -659,17 +657,8 @@ child_return(void *arg)
 	KERNEL_UNLOCK();
 
 	ast(p);
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-		KERNEL_UNLOCK();
-	}
-#endif
+
+	mi_child_return(p);
 }
 
 #ifdef PTRACE
@@ -838,17 +827,14 @@ syscall(struct trapframe *frame)
 	else
 		callp += code;
 
-	oerror = error = 0;
 	if ((argsize = callp->sy_argsize)) {
 		int i;
 
 		for (i = 0, argsize -= argoff * 4;
 		    argsize > 0; i++, argsize -= 4) {
-			error = copyin((void *)(frame->tf_sp +
-			    HPPA_FRAME_ARG(i + 4)), args + i + argoff, 4);
-
-			if (error)
-				break;
+			if ((error = copyin((void *)(frame->tf_sp +
+			    HPPA_FRAME_ARG(i + 4)), args + i + argoff, 4)))
+				goto bad;
 		}
 
 		/*
@@ -860,7 +846,7 @@ syscall(struct trapframe *frame)
 		 * by their normal syscall number, maybe a regress
 		 * test should be used, to watch the behaviour.
 		 */
-		if (!error && argoff < 4) {
+		if (argoff < 4) {
 			int t;
 
 			i = 0;
@@ -884,39 +870,11 @@ syscall(struct trapframe *frame)
 		}
 	}
 
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_call(p, code, args);
-	KERNEL_UNLOCK();
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL)) {
-		KERNEL_LOCK();
-		ktrsyscall(p, code, callp->sy_argsize, args);
-		KERNEL_UNLOCK();
-	}
-#endif
-	if (error)
-		goto bad;
-
 	rval[0] = 0;
 	rval[1] = frame->tf_ret1;
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE)) {
-		KERNEL_LOCK();
-		oerror = error = systrace_redirect(code, p, args, rval);
-		KERNEL_UNLOCK();
-	} else
-#endif
-	{
-		int nolock = (callp->sy_flags & SY_NOLOCK);
-		if (!nolock)
-			KERNEL_LOCK();
-		oerror = error = (*callp->sy_call)(p, args, rval);
-		if (!nolock)
-			KERNEL_UNLOCK();
 
-	}
+	oerror = error = mi_syscall(p, code, callp, args, rval);
+
 	switch (error) {
 	case 0:
 		frame->tf_ret0 = rval[0];
@@ -937,20 +895,11 @@ syscall(struct trapframe *frame)
 		frame->tf_ret1 = 0;
 		break;
 	}
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_ret(p, code, oerror, rval);
-	KERNEL_UNLOCK();
-#endif
+
 	ast(p);
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p, code, oerror, rval[0]);
-		KERNEL_UNLOCK();
-	}
-#endif
+
+	mi_syscall_return(p, code, oerror, rval);
+
 #ifdef DIAGNOSTIC
 	if (curcpu()->ci_cpl != oldcpl) {
 		printf("WARNING: SPL (0x%x) NOT LOWERED ON "
diff --git a/sys/arch/hppa64/hppa64/trap.c b/sys/arch/hppa64/hppa64/trap.c
index 6499e43d94f..f917976a8c5 100644
--- a/sys/arch/hppa64/hppa64/trap.c
+++ b/sys/arch/hppa64/hppa64/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.30 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.31 2012/08/07 05:16:53 guenther Exp $	*/
 
 /*
  * Copyright (c) 2005 Michael Shalayeff
@@ -22,14 +22,12 @@
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/ktrace.h>
 #include <sys/proc.h>
 #include <sys/signalvar.h>
 #include <sys/user.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm.h>
 
 #include <machine/autoconf.h>
@@ -551,14 +549,8 @@ child_return(void *arg)
 	tf->tf_r1 = 0;		/* errno */
 
 	ast(p);
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-#endif
+
+	mi_child_return(p);
 }
 
 void	syscall(struct trapframe *frame);
@@ -615,23 +607,11 @@ syscall(struct trapframe *frame)
 	else
 		callp += code;
 
-	oerror = error = 0;
-
-#ifdef SYSCALL_DEBUG
-	scdebug_call(p, code, args);
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, callp->sy_argsize, args);
-#endif
 	rval[0] = 0;
 	rval[1] = frame->tf_ret1;
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		oerror = error = systrace_redirect(code, p, args, rval);
-	else
-#endif
-		oerror = error = (*callp->sy_call)(p, args, rval);
+
+	oerror = error = mi_syscall(p, code, callp, args, rval);
+
 	switch (error) {
 	case 0:
 		frame->tf_ret0 = rval[0];
@@ -651,15 +631,11 @@ syscall(struct trapframe *frame)
 		frame->tf_ret1 = 0;
 		break;
 	}
-#ifdef SYSCALL_DEBUG
-	scdebug_ret(p, code, oerror, rval);
-#endif
+
 	ast(p);
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, oerror, rval[0]);
-#endif
+
+	mi_syscall_return(p, code, oerror, rval);
+
 #ifdef DIAGNOSTIC
 	if (curcpu()->ci_cpl != oldcpl) {
 		printf("WARNING: SPL (0x%x) NOT LOWERED ON "
diff --git a/sys/arch/i386/i386/trap.c b/sys/arch/i386/i386/trap.c
index 7e8e867c9b7..db4d6b73b67 100644
--- a/sys/arch/i386/i386/trap.c
+++ b/sys/arch/i386/i386/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.102 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.103 2012/08/07 05:16:53 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.95 1996/05/05 06:50:02 mycroft Exp $	*/
 
 /*-
@@ -48,13 +48,8 @@
 #include <sys/acct.h>
 #include <sys/kernel.h>
 #include <sys/signal.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
 #include <sys/syscall.h>
-
-#include "systrace.h"
-#include <dev/systrace.h>
+#include <sys/syscall_mi.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -541,7 +536,7 @@ syscall(struct trapframe *frame)
 	caddr_t params;
 	struct sysent *callp;
 	struct proc *p;
-	int orig_error, error, opc, nsys, lock;
+	int orig_error, error, opc, nsys;
 	register_t code, args[8], rval[2];
 #ifdef DIAGNOSTIC
 	int ocpl = lapic_tpr;
@@ -637,52 +632,16 @@ syscall(struct trapframe *frame)
 			    argsize);
 			break;
 		}
-		error = 0;
 	}
 	else
 #endif
-	if (argsize)
-		error = copyin(params, (caddr_t)args, argsize);
-	else
-		error = 0;
-	orig_error = error;
-
-	lock = !(callp->sy_flags & SY_NOLOCK);	
-
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_call(p, code, args);
-	KERNEL_UNLOCK();
-#endif
-
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL)) {
-		KERNEL_LOCK();
-		ktrsyscall(p, code, argsize, args);
-		KERNEL_UNLOCK();
-	}
-#endif
-
-	if (error) {
+	if (argsize && (error = copyin(params, args, argsize)))
 		goto bad;
-	}
+
 	rval[0] = 0;
 	rval[1] = frame->tf_edx;
 
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE)) {
-		KERNEL_LOCK();
-		orig_error = error = systrace_redirect(code, p, args, rval);
-		KERNEL_UNLOCK();
-	} else
-#endif
-	{
-		if (lock)
-			KERNEL_LOCK();
-			orig_error = error = (*callp->sy_call)(p, args, rval);
-		if (lock)
-			KERNEL_UNLOCK();
-	}
+	orig_error = error = mi_syscall(p, code, callp, args, rval);
 
 	switch (error) {
 	case 0:
@@ -710,19 +669,8 @@ syscall(struct trapframe *frame)
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_ret(p, code, orig_error, rval);
-	KERNEL_UNLOCK();
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p, code, orig_error, rval[0]);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_syscall_return(p, code, orig_error, rval);
+
 #ifdef DIAGNOSTIC
 	if (lapic_tpr != ocpl) {
 		printf("WARNING: SPL (0x%x) NOT LOWERED ON "
@@ -744,15 +692,5 @@ child_return(void *arg)
 
 	KERNEL_UNLOCK();
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_child_return(p);
 }
diff --git a/sys/arch/m68k/m68k/m68k_machdep.c b/sys/arch/m68k/m68k/m68k_machdep.c
index 30251fcddd2..e9e42eb266e 100644
--- a/sys/arch/m68k/m68k/m68k_machdep.c
+++ b/sys/arch/m68k/m68k/m68k_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: m68k_machdep.c,v 1.16 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: m68k_machdep.c,v 1.17 2012/08/07 05:16:53 guenther Exp $	*/
 /*	$NetBSD: m68k_machdep.c,v 1.3 1997/06/12 09:57:04 veego Exp $	*/
 
 /*-
@@ -35,6 +35,7 @@
 #include <sys/exec.h>
 #include <sys/proc.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/ktrace.h>
 #include <sys/user.h>
 
@@ -85,12 +86,5 @@ child_return(arg)
 	f->f_sr &= ~PSL_C;	/* carry bit */
 	f->f_format = FMT0;
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-#endif
+	mi_child_return(p);
 }
diff --git a/sys/arch/m88k/m88k/trap.c b/sys/arch/m88k/m88k/trap.c
index 2cad56abb1d..be32edeedde 100644
--- a/sys/arch/m88k/m88k/trap.c
+++ b/sys/arch/m88k/m88k/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.80 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.81 2012/08/07 05:16:53 guenther Exp $	*/
 /*
  * Copyright (c) 2004, Miodrag Vallat.
  * Copyright (c) 1998 Steve Murphree, Jr.
@@ -51,12 +51,10 @@
 #include <sys/signalvar.h>
 #include <sys/user.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/systm.h>
 #include <sys/ktrace.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm_extern.h>
 
 #include <machine/asm_macro.h>
@@ -1138,7 +1136,6 @@ m88100_syscall(register_t code, struct trapframe *tf)
 	struct proc *p = curproc;
 	int error;
 	register_t args[8], rval[2], *ap;
-	int nolock;
 
 	uvmexp.syscalls++;
 
@@ -1181,45 +1178,16 @@ m88100_syscall(register_t code, struct trapframe *tf)
 		panic("syscall nargs");
 	if (i > nap) {
 		bcopy((caddr_t)ap, (caddr_t)args, nap * sizeof(register_t));
-		error = copyin((caddr_t)tf->tf_r[31], (caddr_t)(args + nap),
-		    (i - nap) * sizeof(register_t));
-	} else {
+		if ((error = copyin((caddr_t)tf->tf_r[31], args + nap,
+		    (i - nap) * sizeof(register_t))))
+			goto bad;
+	} else
 		bcopy((caddr_t)ap, (caddr_t)args, i * sizeof(register_t));
-		error = 0;
-	}
 
-	if (error != 0)
-		goto bad;
-
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_call(p, code, args);
-	KERNEL_UNLOCK();
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL)) {
-		KERNEL_LOCK();
-		ktrsyscall(p, code, callp->sy_argsize, args);
-		KERNEL_UNLOCK();
-	}
-#endif
 	rval[0] = 0;
 	rval[1] = tf->tf_r[3];
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE)) {
-		KERNEL_LOCK();
-		error = systrace_redirect(code, p, args, rval);
-		KERNEL_UNLOCK();
-	} else
-#endif
-	{
-		nolock = (callp->sy_flags & SY_NOLOCK);
-		if (!nolock)
-			KERNEL_LOCK();
-		error = (*callp->sy_call)(p, args, rval);
-		if (!nolock)
-			KERNEL_UNLOCK();
-	}
+
+	error = mi_syscall(p, code, callp, args, rval);
 
 	/*
 	 * system call will look like:
@@ -1267,7 +1235,7 @@ m88100_syscall(register_t code, struct trapframe *tf)
 		tf->tf_epsr &= ~PSR_C;
 		break;
 	default:
-bad:
+	bad:
 		if (p->p_emul->e_errno)
 			error = p->p_emul->e_errno[error];
 		tf->tf_r[2] = error;
@@ -1276,19 +1244,8 @@ bad:
 		tf->tf_sfip = tf->tf_sfip & ~FIP_E;
 		break;
 	}
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_ret(p, code, error, rval);
-	KERNEL_UNLOCK();
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p, code, error, rval[0]);
-		KERNEL_UNLOCK();
-	}
-#endif
+
+	mi_syscall_return(p, code, error, rval);
 }
 #endif /* M88100 */
 
@@ -1302,7 +1259,6 @@ m88110_syscall(register_t code, struct trapframe *tf)
 	struct proc *p = curproc;
 	int error;
 	register_t args[8], rval[2], *ap;
-	int nolock;
 
 	uvmexp.syscalls++;
 
@@ -1345,45 +1301,16 @@ m88110_syscall(register_t code, struct trapframe *tf)
 		panic("syscall nargs");
 	if (i > nap) {
 		bcopy((caddr_t)ap, (caddr_t)args, nap * sizeof(register_t));
-		error = copyin((caddr_t)tf->tf_r[31], (caddr_t)(args + nap),
-		    (i - nap) * sizeof(register_t));
-	} else {
+		if ((error = copyin((caddr_t)tf->tf_r[31], args + nap,
+		    (i - nap) * sizeof(register_t))))
+			goto bad;
+	} else
 		bcopy((caddr_t)ap, (caddr_t)args, i * sizeof(register_t));
-		error = 0;
-	}
-
-	if (error != 0)
-		goto bad;
 
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_call(p, code, args);
-	KERNEL_UNLOCK();
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL)) {
-		KERNEL_LOCK();
-		ktrsyscall(p, code, callp->sy_argsize, args);
-		KERNEL_UNLOCK();
-	}
-#endif
 	rval[0] = 0;
 	rval[1] = tf->tf_r[3];
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE)) {
-		KERNEL_LOCK();
-		error = systrace_redirect(code, p, args, rval);
-		KERNEL_UNLOCK();
-	} else
-#endif
-	{
-		nolock = (callp->sy_flags & SY_NOLOCK);
-		if (!nolock)
-			KERNEL_LOCK();
-		error = (*callp->sy_call)(p, args, rval);
-		if (!nolock)
-			KERNEL_UNLOCK();
-	}
+
+	error = mi_syscall(p, code, callp, args, rval);
 
 	/*
 	 * system call will look like:
@@ -1433,7 +1360,7 @@ m88110_syscall(register_t code, struct trapframe *tf)
 		m88110_skip_insn(tf);
 		break;
 	default:
-bad:
+	bad:
 		if (p->p_emul->e_errno)
 			error = p->p_emul->e_errno[error];
 		tf->tf_r[2] = error;
@@ -1443,19 +1370,7 @@ bad:
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_ret(p, code, error, rval);
-	KERNEL_UNLOCK();
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p, code, error, rval[0]);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_syscall_return(p, code, error, rval);
 }
 #endif	/* M88110 */
 
@@ -1490,18 +1405,8 @@ child_return(arg)
 #endif
 
 	KERNEL_UNLOCK();
-	userret(p);
 
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_child_return(p);
 }
 
 #ifdef PTRACE
diff --git a/sys/arch/mips64/mips64/trap.c b/sys/arch/mips64/mips64/trap.c
index 66725092ad3..c5b73a3b3ba 100644
--- a/sys/arch/mips64/mips64/trap.c
+++ b/sys/arch/mips64/mips64/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.81 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.82 2012/08/07 05:16:54 guenther Exp $	*/
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -50,12 +50,10 @@
 #include <sys/kernel.h>
 #include <sys/signalvar.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/user.h>
 #include <sys/buf.h>
 #include <sys/device.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
 #ifdef PTRACE
 #include <sys/ptrace.h>
 #endif
@@ -80,9 +78,6 @@
 
 #include <sys/syslog.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #define	USERMODE(ps)	(((ps) & SR_KSU_MASK) == SR_KSU_USER)
 
 const char *trap_type[] = {
@@ -402,7 +397,7 @@ printf("SIG-BUSB @%p pc %p, ra %p\n", trapframe->badvaddr, trapframe->pc, trapfr
 		struct sysent *callp;
 		unsigned int code;
 		unsigned long tpc;
-		int numsys;
+		int numsys, error;
 		struct args {
 			register_t i[8];
 		} args;
@@ -439,8 +434,9 @@ printf("SIG-BUSB @%p pc %p, ra %p\n", trapframe->badvaddr, trapframe->pc, trapfr
 				args.i[4] = locr0->a5;
 				args.i[5] = locr0->a6;
 				args.i[6] = locr0->a7;
-				i = copyin((void *)locr0->sp,
-				    &args.i[7], sizeof(register_t));
+				if ((error = copyin((void *)locr0->sp,
+				    &args.i[7], sizeof(register_t))))
+					goto bad;
 			}
 			break;
 
@@ -464,8 +460,9 @@ printf("SIG-BUSB @%p pc %p, ra %p\n", trapframe->badvaddr, trapframe->pc, trapfr
 				args.i[4] = locr0->a5;
 				args.i[5] = locr0->a6;
 				args.i[6] = locr0->a7;
-				i = copyin((void *)locr0->sp, &args.i[7],
-				    sizeof(register_t));
+				if ((error = copyin((void *)locr0->sp,
+				    &args.i[7], sizeof(register_t))))
+					goto bad;
 			}
 			break;
 
@@ -487,41 +484,18 @@ printf("SIG-BUSB @%p pc %p, ra %p\n", trapframe->badvaddr, trapframe->pc, trapfr
 				args.i[7] = locr0->a7;
 			}
 		}
-#ifdef SYSCALL_DEBUG
-		KERNEL_LOCK();
-		scdebug_call(p, code, args.i);
-		KERNEL_UNLOCK();
-#endif
-#ifdef KTRACE
-		if (KTRPOINT(p, KTR_SYSCALL)) {
-			KERNEL_LOCK();
-			ktrsyscall(p, code, callp->sy_argsize, args.i);
-			KERNEL_UNLOCK();
-		}
-#endif
+
 		rval[0] = 0;
 		rval[1] = locr0->v1;
+
 #if defined(DDB) || defined(DEBUG)
 		trapdebug[TRAPSIZE * ci->ci_cpuid + (trppos[ci->ci_cpuid] == 0 ?
 		    TRAPSIZE : trppos[ci->ci_cpuid]) - 1].code = code;
 #endif
 
-#if NSYSTRACE > 0
-		if (ISSET(p->p_flag, P_SYSTRACE)) {
-			KERNEL_LOCK();
-			i = systrace_redirect(code, p, args.i, rval);
-			KERNEL_UNLOCK();
-		} else
-#endif
-		{
-			int nolock = (callp->sy_flags & SY_NOLOCK);
-			if (!nolock)
-				KERNEL_LOCK();
-			i = (*callp->sy_call)(p, &args, rval);
-			if (!nolock)
-				KERNEL_UNLOCK();
-		}
-		switch (i) {
+		error = mi_syscall(p, code, callp, args.i, rval);
+
+		switch (error) {
 		case 0:
 			locr0->v0 = rval[0];
 			locr0->v1 = rval[1];
@@ -536,22 +510,14 @@ printf("SIG-BUSB @%p pc %p, ra %p\n", trapframe->badvaddr, trapframe->pc, trapfr
 			break;	/* nothing to do */
 
 		default:
-			locr0->v0 = i;
+		bad:
+			locr0->v0 = error;
 			locr0->a3 = 1;
 		}
-#ifdef SYSCALL_DEBUG
-		KERNEL_LOCK();
-		scdebug_ret(p, code, i, rval);
-		KERNEL_UNLOCK();
-#endif
-#ifdef KTRACE
-		if (KTRPOINT(p, KTR_SYSRET)) {
-			KERNEL_LOCK();
-			ktrsysret(p, code, i, rval[0]);
-			KERNEL_UNLOCK();
-		}
-#endif
-		goto out;
+
+		mi_syscall_return(p, code, error, rval);
+
+		return;
 	    }
 
 	case T_BREAK:
@@ -846,18 +812,7 @@ child_return(arg)
 
 	KERNEL_UNLOCK();
 
-	userret(p);
-
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_child_return(p);
 }
 
 #if defined(DDB) || defined(DEBUG)
diff --git a/sys/arch/mvme68k/mvme68k/trap.c b/sys/arch/mvme68k/mvme68k/trap.c
index 01ae2c3b22f..1a3cefe82fd 100644
--- a/sys/arch/mvme68k/mvme68k/trap.c
+++ b/sys/arch/mvme68k/mvme68k/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.75 2011/11/16 20:50:19 deraadt Exp $ */
+/*	$OpenBSD: trap.c,v 1.76 2012/08/07 05:16:54 guenther Exp $ */
 
 /*
  * Copyright (c) 1995 Theo de Raadt
@@ -70,11 +70,9 @@
 #include <sys/signalvar.h>
 #include <sys/resourcevar.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/syslog.h>
 #include <sys/user.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
 
 #include <machine/db_machdep.h>
 #include <machine/cpu.h>
@@ -82,9 +80,6 @@
 #include <machine/reg.h>
 #include <machine/trap.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm_extern.h>
 #include <uvm/uvm_pmap.h>
 
@@ -893,9 +888,9 @@ syscall(code, frame)
 		 */
 		if (callp != sysent)
 			break;
-		if (copyin(params + _QUAD_LOWWORD * sizeof(int), &code,
-		    sizeof(register_t)) != 0)
-			code = -1;
+		if ((error = copyin(params + _QUAD_LOWWORD * sizeof(int),
+		    &code, sizeof(register_t))))
+			goto bad;
 		params += sizeof(quad_t);
 		break;
 	default:
@@ -906,27 +901,14 @@ syscall(code, frame)
 	else
 		callp	+= code;
 	argsize = callp->sy_argsize;
-	if (argsize)
-		error = copyin(params, (caddr_t)args, argsize);
-	else
-		error	= 0;
-#ifdef SYSCALL_DEBUG
-	scdebug_call(p, code, args);
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, argsize, args);
-#endif
-	if (error)
+	if (argsize && (error = copyin(params, args, argsize)))
 		goto bad;
+
 	rval[0] = 0;
 	rval[1] = frame.f_regs[D1];
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		error = systrace_redirect(code, p, args, rval);
-	else
-#endif
-		error = (*callp->sy_call)(p, args, rval);
+
+	error = mi_syscall(p, code, callp, args, rval);
+
 	switch (error) {
 	case 0:
 		frame.f_regs[D0] = rval[0];
@@ -944,7 +926,7 @@ syscall(code, frame)
 		/* nothing to do */
 		break;
 	default:
-bad:
+	bad:
 		if (p->p_emul->e_errno)
 			error = p->p_emul->e_errno[error];
 		frame.f_regs[D0] = error;
@@ -952,14 +934,7 @@ bad:
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	scdebug_ret(p, code, error, rval);
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, error, rval[0]);
-#endif
+	mi_syscall_return(p, code, error, rval);
 }
 
 typedef SLIST_HEAD(,intrhand) intrhand_t;
diff --git a/sys/arch/powerpc/powerpc/trap.c b/sys/arch/powerpc/powerpc/trap.c
index 8f511c76951..e18597f1ce9 100644
--- a/sys/arch/powerpc/powerpc/trap.c
+++ b/sys/arch/powerpc/powerpc/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.90 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.91 2012/08/07 05:16:54 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.3 1996/10/13 03:31:37 christos Exp $	*/
 
 /*
@@ -36,6 +36,7 @@
 #include <sys/signalvar.h>
 #include <sys/reboot.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/systm.h>
 #include <sys/user.h>
 #include <sys/ktrace.h>
@@ -52,9 +53,6 @@
 #include <machine/trap.h>
 #include <machine/db_machdep.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm_extern.h>
 
 #include <ddb/db_extern.h>
@@ -442,53 +440,18 @@ printf("isi iar %x lr %x\n", frame->srr0, frame->lr);
 			if (argsize > n * sizeof(register_t)) {
 				bcopy(params, args, n * sizeof(register_t));
 
-				error = copyin(MOREARGS(frame->fixreg[1]),
-				   args + n, argsize - n * sizeof(register_t));
-				if (error) {
-#ifdef	KTRACE
-					/* Can't get all the arguments! */
-					if (KTRPOINT(p, KTR_SYSCALL))
-						ktrsyscall(p, code,
-							   argsize, args);
-#endif
-					goto syscall_bad;
-				}
+				if ((error = copyin(MOREARGS(frame->fixreg[1]),
+				   args + n,
+				   argsize - n * sizeof(register_t))))
+					goto bad;
 				params = args;
 			}
 
-#ifdef	KTRACE
-			if (KTRPOINT(p, KTR_SYSCALL)) {
-				KERNEL_LOCK();
-				ktrsyscall(p, code, argsize, params);
-				KERNEL_UNLOCK();
-			}
-#endif
 			rval[0] = 0;
 			rval[1] = frame->fixreg[FIRSTARG + 1];
 
-#ifdef SYSCALL_DEBUG
-			KERNEL_LOCK();
-			scdebug_call(p, code, params);
-			KERNEL_UNLOCK();
-#endif
+			error = mi_syscall(p, code, callp, params, rval);
 
-			
-#if NSYSTRACE > 0
-			if (ISSET(p->p_flag, P_SYSTRACE)) {
-				KERNEL_LOCK();
-				error = systrace_redirect(code, p, params,
-				    rval);
-				KERNEL_UNLOCK();
-			} else
-#endif
-			{
-				nolock = (callp->sy_flags & SY_NOLOCK);
-				if (!nolock)
-					KERNEL_LOCK();
-				error = (*callp->sy_call)(p, params, rval);
-				if (!nolock)
-					KERNEL_UNLOCK();
-			}
 			switch (error) {
 			case 0:
 				frame->fixreg[0] = error;
@@ -506,7 +469,7 @@ printf("isi iar %x lr %x\n", frame->srr0, frame->lr);
 				/* nothing to do */
 				break;
 			default:
-syscall_bad:
+			bad:
 				if (p->p_emul->e_errno)
 					error = p->p_emul->e_errno[error];
 				frame->fixreg[0] = error;
@@ -515,20 +478,10 @@ syscall_bad:
 				frame->cr |= 0x10000000;
 				break;
 			}
-#ifdef SYSCALL_DEBUG
-			KERNEL_LOCK();
-			scdebug_ret(p, code, error, rval); 
-			KERNEL_UNLOCK();
-#endif  
-#ifdef	KTRACE
-			if (KTRPOINT(p, KTR_SYSRET)) {
-				KERNEL_LOCK();
-				ktrsysret(p, code, error, rval[0]);
-				KERNEL_UNLOCK();
-			}
-#endif
+
+			mi_syscall_return(p, code, error, rval);
+			goto finish;
 		}
-		break;
 
 	case EXC_FPU|EXC_USER:
 		if (ci->ci_fpuproc)
@@ -682,6 +635,7 @@ for (i = 0; i < errnum; i++) {
 
 	userret(p);
 
+finish:
 	/*
 	 * If someone stole the fpu while we were away, disable it
 	 */
@@ -716,18 +670,7 @@ child_return(void *arg)
 
 	KERNEL_UNLOCK();
 
-	userret(p);
-
-#ifdef	KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_child_return(p);
 }
 
 int
diff --git a/sys/arch/sh/sh/trap.c b/sys/arch/sh/sh/trap.c
index 826dc4b71d3..f3b2dee761f 100644
--- a/sys/arch/sh/sh/trap.c
+++ b/sys/arch/sh/sh/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.19 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.20 2012/08/07 05:16:54 guenther Exp $	*/
 /*	$NetBSD: exception.c,v 1.32 2006/09/04 23:57:52 uwe Exp $	*/
 /*	$NetBSD: syscall.c,v 1.6 2006/03/07 07:21:50 thorpej Exp $	*/
 
@@ -89,15 +89,7 @@
 #include <sys/resourcevar.h>
 #include <sys/signalvar.h>
 #include <sys/syscall.h>
-
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
-
-#include "systrace.h"
-#if NSYSTRACE > 0
-#include <dev/systrace.h>
-#endif
+#include <sys/syscall_mi.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -584,12 +576,11 @@ syscall(struct proc *p, struct trapframe *tf)
 			args[2] = tf->tf_r7;
 			if (argsize > 3 * sizeof(int)) {
 				argsize -= 3 * sizeof(int);
-				error = copyin(params, (caddr_t)&args[3],
-					       argsize);
-			} else
-				error = 0;
-		} else
-			error = 0;
+				if ((error = copyin(params, &args[3],
+				    argsize)))
+					goto bad;
+			}
+		}
 		break;
 	case SYS___syscall:
 		if (argsize) {
@@ -597,12 +588,11 @@ syscall(struct proc *p, struct trapframe *tf)
 			args[1] = tf->tf_r7;
 			if (argsize > 2 * sizeof(int)) {
 				argsize -= 2 * sizeof(int);
-				error = copyin(params, (caddr_t)&args[2],
-					       argsize);
-			} else
-				error = 0;
-		} else
-			error = 0;
+				if ((error = copyin(params, &args[2],
+				    argsize)))
+					goto bad;
+			}
+		}
 		break;
 	default:
 		if (argsize) {
@@ -612,36 +602,19 @@ syscall(struct proc *p, struct trapframe *tf)
 			args[3] = tf->tf_r7;
 			if (argsize > 4 * sizeof(int)) {
 				argsize -= 4 * sizeof(int);
-				error = copyin(params, (caddr_t)&args[4],
-					       argsize);
-			} else
-				error = 0;
-		} else
-			error = 0;
+				if ((error = copyin(params, &args[4],
+				    argsize)))
+					goto bad;
+			}
+		}
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	scdebug_call(p, code, args);
-#endif
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, callp->sy_argsize, args);
-#endif
-
-	if (error != 0)
-		goto bad;
-
 	rval[0] = 0;
 	rval[1] = tf->tf_r1;
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		error = systrace_redirect(code, p, args, rval);
-	else
-#endif
-		error = (*callp->sy_call)(p, args, rval);
 
-bad:
+	error = mi_syscall(p, code, callp, args, rval);
+
 	switch (oerror = error) {
 	case 0:
 		tf->tf_r0 = rval[0];
@@ -656,6 +629,7 @@ bad:
 		/* nothing to do */
 		break;
 	default:
+	bad:
 		if (p->p_emul->e_errno)
 			error = p->p_emul->e_errno[error];
 		tf->tf_r0 = error;
@@ -663,14 +637,7 @@ bad:
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	scdebug_ret(p, code, oerror, rval);
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, oerror, rval[0]);
-#endif
+	mi_syscall_return(p, code, oerror, rval);
 }
 
 /*
@@ -688,14 +655,6 @@ child_return(void *arg)
 	tf->tf_r0 = 0;
 	tf->tf_ssr |= PSL_TBIT; /* This indicates no error. */
 
-	userret(p);
-
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-#endif
+	mi_child_return(p);
 }
 
diff --git a/sys/arch/solbourne/solbourne/trap.c b/sys/arch/solbourne/solbourne/trap.c
index d80811eb4db..26be7192169 100644
--- a/sys/arch/solbourne/solbourne/trap.c
+++ b/sys/arch/solbourne/solbourne/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.15 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.16 2012/08/07 05:16:54 guenther Exp $	*/
 /*	OpenBSD: trap.c,v 1.42 2004/12/06 20:12:25 miod Exp 	*/
 
 /*
@@ -60,13 +60,8 @@
 #include <sys/signal.h>
 #include <sys/wait.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/syslog.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
-
-#include "systrace.h"
-#include <dev/systrace.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -832,33 +827,20 @@ syscall(code, tf, pc)
 		if (i > nap) {	/* usually false */
 			if (i > 8)
 				panic("syscall nargs");
-			error = copyin((caddr_t)tf->tf_out[6] +
+			if ((error = copyin((caddr_t)tf->tf_out[6] +
 			    offsetof(struct frame, fr_argx),
-			    (caddr_t)&args.i[nap], (i - nap) * sizeof(register_t));
-			if (error) {
-#ifdef KTRACE
-				if (KTRPOINT(p, KTR_SYSCALL))
-					ktrsyscall(p, code,
-					    callp->sy_argsize, args.i);
-#endif
+			    &args.i[nap], (i - nap) * sizeof(register_t))))
 				goto bad;
-			}
 			i = nap;
 		}
-		copywords(ap, args.i, i * sizeof(register_t));
+		if (error == 0)
+			copywords(ap, args.i, i * sizeof(register_t));
 	}
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, callp->sy_argsize, args.i);
-#endif
+
 	rval[0] = 0;
 	rval[1] = tf->tf_out[1];
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		error = systrace_redirect(code, p, &args, rval);
-	else
-#endif
-		error = (*callp->sy_call)(p, &args, rval);
+
+	error = mi_syscall(p, code, callp, args.i, rval);
 
 	switch (error) {
 	case 0:
@@ -898,11 +880,8 @@ syscall(code, tf, pc)
 		break;
 	}
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, error, rval[0]);
-#endif
+	mi_syscall_return(p, code, error, rval);
+
 	share_fpu(p, tf);
 }
 
@@ -923,12 +902,5 @@ child_return(arg)
 	tf->tf_out[1] = 0;
 	tf->tf_psr &= ~PSR_C;
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-#endif
+	mi_child_return(p);
 }
diff --git a/sys/arch/sparc/sparc/trap.c b/sys/arch/sparc/sparc/trap.c
index d659e228cb1..61e67dd8cdd 100644
--- a/sys/arch/sparc/sparc/trap.c
+++ b/sys/arch/sparc/sparc/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.59 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.60 2012/08/07 05:16:54 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.58 1997/09/12 08:55:01 pk Exp $ */
 
 /*
@@ -60,13 +60,8 @@
 #include <sys/signal.h>
 #include <sys/wait.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/syslog.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
-
-#include "systrace.h"
-#include <dev/systrace.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -1015,33 +1010,20 @@ syscall(code, tf, pc)
 		if (i > nap) {	/* usually false */
 			if (i > 8)
 				panic("syscall nargs");
-			error = copyin((caddr_t)tf->tf_out[6] +
+			if ((error = copyin((caddr_t)tf->tf_out[6] +
 			    offsetof(struct frame, fr_argx),
-			    (caddr_t)&args.i[nap], (i - nap) * sizeof(register_t));
-			if (error) {
-#ifdef KTRACE
-				if (KTRPOINT(p, KTR_SYSCALL))
-					ktrsyscall(p, code,
-					    callp->sy_argsize, args.i);
-#endif
+			    &args.i[nap], (i - nap) * sizeof(register_t))))
 				goto bad;
-			}
 			i = nap;
 		}
-		copywords(ap, args.i, i * sizeof(register_t));
+		if (error == 0)
+			copywords(ap, args.i, i * sizeof(register_t));
 	}
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, code, callp->sy_argsize, args.i);
-#endif
+
 	rval[0] = 0;
 	rval[1] = tf->tf_out[1];
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		error = systrace_redirect(code, p, &args, rval);
-	else
-#endif
-		error = (*callp->sy_call)(p, &args, rval);
+
+	error = mi_syscall(p, code, callp, args.i, rval);
 
 	switch (error) {
 	case 0:
@@ -1081,11 +1063,7 @@ syscall(code, tf, pc)
 		break;
 	}
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, code, error, rval[0]);
-#endif
+	mi_syscall_return(p, code, error, rval);
 	share_fpu(p, tf);
 }
 
@@ -1106,12 +1084,5 @@ child_return(arg)
 	tf->tf_out[1] = 0;
 	tf->tf_psr &= ~PSR_C;
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-#endif
+	mi_child_return(p);
 }
diff --git a/sys/arch/sparc64/sparc64/trap.c b/sys/arch/sparc64/sparc64/trap.c
index df20ef0db5e..4e770305213 100644
--- a/sys/arch/sparc64/sparc64/trap.c
+++ b/sys/arch/sparc64/sparc64/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.75 2012/04/11 14:38:55 mikeb Exp $	*/
+/*	$OpenBSD: trap.c,v 1.76 2012/08/07 05:16:54 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.73 2001/08/09 01:03:01 eeh Exp $ */
 
 /*
@@ -60,13 +60,8 @@
 #include <sys/signal.h>
 #include <sys/wait.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/syslog.h>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
-
-#include "systrace.h"
-#include <dev/systrace.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -1228,7 +1223,7 @@ syscall(tf, code, pc)
 	int64_t *ap;
 	const struct sysent *callp;
 	struct proc *p;
-	int error = 0, new, lock;
+	int error, new;
 	register_t args[8];
 	register_t rval[2];
 
@@ -1249,8 +1244,6 @@ syscall(tf, code, pc)
 	callp = p->p_emul->e_sysent;
 	nsys = p->p_emul->e_nsysent;
 
-	lock = !(callp->sy_flags & SY_NOLOCK);
-
 	/*
 	 * The first six system call arguments are in the six %o registers.
 	 * Any arguments beyond that are in the `argument extension' area
@@ -1298,50 +1291,28 @@ syscall(tf, code, pc)
 			if (i > 8)
 				panic("syscall nargs");
 			/* Read the whole block in */
-			error = copyin((caddr_t)(u_long)tf->tf_out[6] + BIAS +
-				       offsetof(struct frame64, fr_argx),
-				       (caddr_t)&args[nap], (i - nap) * sizeof(register_t));
+			if ((error = copyin((caddr_t)(u_long)tf->tf_out[6]
+			    + BIAS + offsetof(struct frame64, fr_argx),
+			    &args[nap], (i - nap) * sizeof(register_t))))
+				goto bad;
 			i = nap;
 		}
-		/* It should be faster to do <=6 longword copies than call bcopy */
+		/*
+		 * It should be faster to do <= 6 longword copies than
+		 * to call bcopy
+		 */
 		for (argp = args; i--;) 
 			*argp++ = *ap++;
-		
-#ifdef KTRACE
-		if (KTRPOINT(p, KTR_SYSCALL)) {
-			KERNEL_LOCK();
-			ktrsyscall(p, code, callp->sy_argsize, args);
-			KERNEL_UNLOCK();
-		}
-#endif
-		if (error)
-			goto bad;
 	} else {
 		error = EFAULT;
 		goto bad;
 	}
 
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_call(p, code, args);
-	KERNEL_UNLOCK();
-#endif
 	rval[0] = 0;
 	rval[1] = tf->tf_out[1];
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE)) {
-		KERNEL_LOCK();
-		error = systrace_redirect(code, p, args, rval);
-		KERNEL_UNLOCK();
-	} else
-#endif
-	{
-		if (lock)
-			KERNEL_LOCK();
-		error = (*callp->sy_call)(p, args, rval);
-		if (lock)
-			KERNEL_UNLOCK();
-	}
+
+	error = mi_syscall(p, code, callp, args, rval);
+
 	switch (error) {
 		vaddr_t dest;
 	case 0:
@@ -1381,19 +1352,7 @@ syscall(tf, code, pc)
 		break;
 	}
 
-#ifdef SYSCALL_DEBUG
-	KERNEL_LOCK();
-	scdebug_ret(p, code, error, rval);
-	KERNEL_UNLOCK();
-#endif
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p, code, error, rval[0]);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_syscall_return(p, code, error, rval);
 	share_fpu(p, tf);
 }
 
@@ -1416,16 +1375,6 @@ child_return(arg)
 
 	KERNEL_UNLOCK();
 
-	userret(p);
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET)) {
-		KERNEL_LOCK();
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-		KERNEL_UNLOCK();
-	}
-#endif
+	mi_child_return(p);
 }
 
diff --git a/sys/arch/vax/vax/trap.c b/sys/arch/vax/vax/trap.c
index 13b4d32b8fa..e1b7a49528f 100644
--- a/sys/arch/vax/vax/trap.c
+++ b/sys/arch/vax/vax/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.44 2012/04/23 19:04:07 miod Exp $     */
+/*	$OpenBSD: trap.c,v 1.45 2012/08/07 05:16:54 guenther Exp $     */
 /*	$NetBSD: trap.c,v 1.47 1999/08/21 19:26:20 matt Exp $     */
 /*
  * Copyright (c) 1994 Ludd, University of Lule}, Sweden.
@@ -36,13 +36,11 @@
 #include <sys/proc.h>
 #include <sys/user.h>
 #include <sys/syscall.h>
+#include <sys/syscall_mi.h>
 #include <sys/systm.h>
 #include <sys/signalvar.h>
 #include <sys/exec.h>
 
-#include "systrace.h"
-#include <dev/systrace.h>
-
 #include <uvm/uvm_extern.h>
 
 #include <machine/mtpr.h>
@@ -56,9 +54,6 @@
 #include <machine/db_machdep.h>
 #endif
 #include <kern/syscalls.c>
-#ifdef KTRACE
-#include <sys/ktrace.h>
-#endif
 
 #ifdef TRAPDEBUG
 volatile int startsysc = 0, faultdebug = 0;
@@ -368,27 +363,12 @@ if(startsysc)printf("trap syscall %s pc %lx, psl %lx, sp %lx, pid %d, frame %p\n
 	rval[0] = 0;
 	rval[1] = frame->r1;
 	if(callp->sy_narg) {
-		err = copyin((char *)frame->ap + 4, args, callp->sy_argsize);
-		if (err) {
-#ifdef KTRACE
-			if (KTRPOINT(p, KTR_SYSCALL))
-				ktrsyscall(p, frame->code,
-				    callp->sy_argsize, args);
-#endif
+		if ((error = copyin((char *)frame->ap + 4, args,
+		    callp->sy_argsize)))
 			goto bad;
-		}
 	}
 
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSCALL))
-		ktrsyscall(p, frame->code, callp->sy_argsize, args);
-#endif
-#if NSYSTRACE > 0
-	if (ISSET(p->p_flag, P_SYSTRACE))
-		err = systrace_redirect(frame->code, curproc, args, rval);
-	else
-#endif
-		err = (*callp->sy_call)(curproc, args, rval);
+	err = mi_syscall(p, frame->code, callp, args, rval);
 
 #ifdef TRAPDEBUG
 if(startsysc)
@@ -413,17 +393,13 @@ bad:
 		break;
 
 	default:
+	bad:
 		exptr->r0 = err;
 		exptr->psl |= PSL_C;
 		break;
 	}
 
-	userret(p);
-
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p, frame->code, err, rval[0]);
-#endif
+	mi_syscall_return(p, frame->code, err, rval);
 }
 
 void
@@ -437,13 +413,5 @@ child_return(arg)
 	frame->r1 = frame->r0 = 0;
 	frame->psl &= ~PSL_C;
 
-	userret(p);
-
-#ifdef KTRACE
-	if (KTRPOINT(p, KTR_SYSRET))
-		ktrsysret(p,
-		    (p->p_flag & P_THREAD) ? SYS___tfork :
-		    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork,
-		    0, 0);
-#endif
+	mi_child_return(p);
 }
diff --git a/sys/kern/kern_xxx.c b/sys/kern/kern_xxx.c
index 2b0331c3378..063385c4be3 100644
--- a/sys/kern/kern_xxx.c
+++ b/sys/kern/kern_xxx.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_xxx.c,v 1.22 2012/07/09 15:43:36 deraadt Exp $	*/
+/*	$OpenBSD: kern_xxx.c,v 1.23 2012/08/07 05:16:54 guenther Exp $	*/
 /*	$NetBSD: kern_xxx.c,v 1.32 1996/04/22 01:38:41 christos Exp $	*/
 
 /*
@@ -83,7 +83,7 @@ __stack_smash_handler(char func[], int damaged)
 int	scdebug = SCDEBUG_CALLS|SCDEBUG_RETURNS|SCDEBUG_SHOWARGS;
 
 void
-scdebug_call(struct proc *p, register_t code, register_t args[])
+scdebug_call(struct proc *p, register_t code, const register_t args[])
 {
 	struct sysent *sy;
 	struct emul *em;
@@ -116,7 +116,8 @@ scdebug_call(struct proc *p, register_t code, register_t args[])
 }
 
 void
-scdebug_ret(struct proc *p, register_t code, int error, register_t retval[])
+scdebug_ret(struct proc *p, register_t code, int error,
+    const register_t retval[])
 {
 	struct sysent *sy;
 	struct emul *em;
diff --git a/sys/sys/syscall_mi.h b/sys/sys/syscall_mi.h
new file mode 100644
index 00000000000..8f6071c5b2a
--- /dev/null
+++ b/sys/sys/syscall_mi.h
@@ -0,0 +1,139 @@
+/*	$OpenBSD: syscall_mi.h,v 1.1 2012/08/07 05:16:53 guenther Exp $	*/
+
+/*
+ * Copyright (c) 1982, 1986, 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)kern_xxx.c	8.2 (Berkeley) 11/14/93
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+
+#ifdef KTRACE
+#include <sys/ktrace.h>
+#endif
+
+#include "systrace.h"
+#if NSYSTRACE > 0
+#include <dev/systrace.h>
+#endif
+
+
+/*
+ * The MD setup for a system call has been done; here's the MI part.
+ */
+static inline int
+mi_syscall(struct proc *p, register_t code, const struct sysent *callp,
+    register_t *argp, register_t retval[2])
+{
+	int lock = !(callp->sy_flags & SY_NOLOCK);
+	int error;
+
+#ifdef SYSCALL_DEBUG
+	KERNEL_LOCK();
+	scdebug_call(p, code, argp);
+	KERNEL_UNLOCK();
+#endif
+#ifdef KTRACE
+	if (KTRPOINT(p, KTR_SYSCALL)) {
+		KERNEL_LOCK();
+		ktrsyscall(p, code, callp->sy_argsize, argp);
+		KERNEL_UNLOCK();
+	}
+#endif
+
+#if NSYSTRACE > 0
+	if (ISSET(p->p_flag, P_SYSTRACE)) {
+		KERNEL_LOCK();
+		error = systrace_redirect(code, p, argp, retval);
+		KERNEL_UNLOCK();
+	} else
+#endif
+	{
+		if (lock)
+			KERNEL_LOCK();
+		error = (*callp->sy_call)(p, argp, retval);
+		if (lock)
+			KERNEL_UNLOCK();
+	}
+
+	return (error);
+}
+
+/*
+ * Finish MI stuff on return, after the registers have been set
+ */
+static inline void
+mi_syscall_return(struct proc *p, register_t code, int error,
+    const register_t retval[2])
+{
+#ifdef SYSCALL_DEBUG
+	KERNEL_LOCK();
+	scdebug_ret(p, code, error, retval);
+	KERNEL_UNLOCK();
+#endif
+
+	userret(p);
+
+#ifdef KTRACE
+	if (KTRPOINT(p, KTR_SYSRET)) {
+		KERNEL_LOCK();
+		ktrsysret(p, code, error, retval[0]);
+		KERNEL_UNLOCK();
+	}
+#endif
+}
+
+/*
+ * Finish MI stuff for a new process/thread to return
+ */
+static inline void
+mi_child_return(struct proc *p)
+{
+	int code = (p->p_flag & P_THREAD) ? SYS___tfork :
+	    (p->p_p->ps_flags & PS_PPWAIT) ? SYS_vfork : SYS_fork;
+
+#ifdef SYSCALL_DEBUG
+	const register_t child_retval[2] = { 0, 1 };
+
+	KERNEL_LOCK();
+	scdebug_ret(p, code, 0, child_retval);
+	KERNEL_UNLOCK();
+#endif
+
+	userret(p);
+
+#ifdef KTRACE
+	if (KTRPOINT(p, KTR_SYSRET)) {
+		KERNEL_LOCK();
+		ktrsysret(p, code, 0, 0);
+		KERNEL_UNLOCK();
+	}
+#endif
+}
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 5dd1bfd8766..1c20ea6241f 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: systm.h,v 1.91 2012/08/02 03:18:48 guenther Exp $	*/
+/*	$OpenBSD: systm.h,v 1.92 2012/08/07 05:16:53 guenther Exp $	*/
 /*	$NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $	*/
 
 /*-
@@ -133,8 +133,9 @@ extern struct sysent {		/* system call table */
 #endif
 
 #if defined(_KERNEL) && defined(SYSCALL_DEBUG)
-void scdebug_call(struct proc *p, register_t code, register_t retval[]);
-void scdebug_ret(struct proc *p, register_t code, int error, register_t retval[]);
+void scdebug_call(struct proc *p, register_t code, const register_t retval[]);
+void scdebug_ret(struct proc *p, register_t code, int error,
+    const register_t retval[]);
 #endif /* _KERNEL && SYSCALL_DEBUG */
 
 extern int boothowto;		/* reboot flags, from console subsystem */