diff --git a/sys/arch/x86/conf/files.x86 b/sys/arch/x86/conf/files.x86
index f35b062f9e28..3cf97c0e8585 100644
--- a/sys/arch/x86/conf/files.x86
+++ b/sys/arch/x86/conf/files.x86
@@ -1,7 +1,7 @@
-#	$NetBSD: files.x86,v 1.3 2003/02/27 01:50:40 fvdl Exp $
+#	$NetBSD: files.x86,v 1.4 2003/03/01 22:55:02 fvdl Exp $
 
 # options for MP configuration through the MP spec
-defflag opt_mpbios.h MPBIOS MPVERBOSE MPDEBUGA
+defflag opt_mpbios.h MPBIOS MPVERBOSE MPDEBUG
 
 # MTRR support
 defflag                 MTRR
@@ -9,13 +9,14 @@ defflag                 MTRR
 define  mainbus { [apid = -1] }
 
 file	arch/x86/x86/apic.c		ioapic | lapic
+file	arch/x86/x86/bus_machdep.c
 file	arch/x86/x86/consinit.c
 file	arch/x86/x86/i8259.c
 file	arch/x86/x86/intr.c
-file	arch/x86/x86/softintr.c
-file	arch/x86/x86/bus_machdep.c
 file	arch/x86/x86/ipi.c		multiprocessor
+file	arch/x86/x86/lock_machdep.c	lockdebug
 file	arch/x86/x86/mtrr_i686.c	mtrr
+file	arch/x86/x86/softintr.c
 
 define lapic
 file	arch/x86/x86/lapic.c		lapic needs-flag
diff --git a/sys/arch/x86/x86/lock_machdep.c b/sys/arch/x86/x86/lock_machdep.c
new file mode 100644
index 000000000000..1c233d91db98
--- /dev/null
+++ b/sys/arch/x86/x86/lock_machdep.c
@@ -0,0 +1,143 @@
+/* 	$NetBSD: lock_machdep.c,v 1.1 2003/03/01 22:55:02 fvdl Exp $ */
+
+/*-
+ * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
+ * NASA Ames Research Center.
+ *
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the NetBSD
+ *	Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ */
+
+#include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
+
+/*
+ * Machine-dependent spin lock operations.
+ */
+
+#include "opt_ddb.h"
+
+#include <sys/types.h>
+#include <sys/lock.h>
+#include <sys/systm.h>
+
+#include <machine/atomic.h>
+#include <machine/cpu.h>
+
+#include <ddb/db_output.h>
+
+void
+__cpu_simple_lock_init(lockp)
+	__cpu_simple_lock_t *lockp;
+{
+
+	*lockp = __SIMPLELOCK_UNLOCKED;
+}
+
+#if defined (DEBUG) && defined(DDB)
+int spin_limit = 10000000;
+__cpu_simple_lock_t *wantlock[X86_MAXPROCS], *gotlock[X86_MAXPROCS];
+#endif
+
+void
+__cpu_simple_lock(lockp)
+	__cpu_simple_lock_t *lockp;
+{
+#if defined (DEBUG)
+#if defined(DDB)
+	int spincount = 0;
+	int cpu = cpu_number();
+	int limit = spin_limit * (cpu + 1);
+#endif
+	__cpu_simple_lock_t v = *lockp;
+
+	KDASSERT((v == __SIMPLELOCK_LOCKED) || (v == __SIMPLELOCK_UNLOCKED));
+#if defined(DDB)
+	wantlock[cpu] = lockp;
+#endif
+#endif
+
+	while (x86_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED) ==
+	    __SIMPLELOCK_LOCKED) {
+#if defined(DEBUG) && defined(DDB)
+		spincount++;
+		if (spincount == limit) {
+			extern int db_active;
+			spincount = 0;
+
+			if (db_active) {
+				db_printf("cpu%d: spinout while in debugger\n",
+				    cpu);
+				while (db_active)
+					;
+			}
+			db_printf("cpu%d: spinout\n", cpu);
+			Debugger();
+		}
+#endif
+	}
+#if defined(DEBUG) && defined(DDB)
+	wantlock[cpu] = 0;
+	gotlock[cpu] = lockp;
+#endif
+	__lockbarrier();
+}
+
+int
+__cpu_simple_lock_try(lockp)
+	__cpu_simple_lock_t *lockp;
+{
+	int r;
+#ifdef DEBUG
+	__cpu_simple_lock_t v = *lockp;
+
+	KDASSERT((v == __SIMPLELOCK_LOCKED) || (v == __SIMPLELOCK_UNLOCKED));
+#endif
+	r = (x86_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
+	    == __SIMPLELOCK_UNLOCKED);
+
+	__lockbarrier();
+
+	return (r);
+}
+
+void
+__cpu_simple_unlock(lockp)
+	__cpu_simple_lock_t *lockp;
+{
+#ifdef DEBUG
+	__cpu_simple_lock_t v = *lockp;
+
+	KDASSERT((v == __SIMPLELOCK_LOCKED) || (v == __SIMPLELOCK_UNLOCKED));
+#endif
+	__lockbarrier();
+	*lockp = __SIMPLELOCK_UNLOCKED;
+}