diff --git a/sys/arch/usermode/dev/cpu.c b/sys/arch/usermode/dev/cpu.c
index 2cb11c132624..0c3dfd1ac3b2 100644
--- a/sys/arch/usermode/dev/cpu.c
+++ b/sys/arch/usermode/dev/cpu.c
@@ -1,4 +1,4 @@
-/* $NetBSD: cpu.c,v 1.42 2011/09/09 18:41:16 reinoud Exp $ */
+/* $NetBSD: cpu.c,v 1.43 2011/09/09 20:06:04 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2007 Jared D. McNeill <jmcneill@invisible.ca>
@@ -30,7 +30,7 @@
 #include "opt_hz.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.42 2011/09/09 18:41:16 reinoud Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.43 2011/09/09 20:06:04 reinoud Exp $");
 
 #include <sys/param.h>
 #include <sys/conf.h>
@@ -315,20 +315,20 @@ cpu_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize,
 	if (thunk_getcontext(&pcb2->pcb_ucp))
 		panic("getcontext failed");
 
-	/* set up the ucontext for the userland */
+	/* set up the ucontext for the userland switch */
 	pcb2->pcb_ucp.uc_stack.ss_sp = stack;
 	pcb2->pcb_ucp.uc_stack.ss_size = stacksize;
 	pcb2->pcb_ucp.uc_link = &pcb2->pcb_userland_ucp;
 	pcb2->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU;
-	thunk_makecontext(&pcb2->pcb_ucp, (void (*)(void))cpu_lwp_trampoline,
-	    2, func, arg);
+	thunk_makecontext(&pcb2->pcb_ucp, (void (*)(void)) cpu_lwp_trampoline,
+	    2, func, arg, NULL);
 
 	/* set up the ucontext for the syscall */
 	pcb2->pcb_syscall_ucp.uc_flags = _UC_CPU;
 	pcb2->pcb_syscall_ucp.uc_link = &pcb2->pcb_userland_ucp;
 	pcb2->pcb_syscall_ucp.uc_stack.ss_size = 0;	/* no stack move */
 	thunk_makecontext(&pcb2->pcb_syscall_ucp, (void (*)(void)) syscall,
-	    0, NULL, NULL);
+	    0, NULL, NULL, NULL);
 }
 
 void
diff --git a/sys/arch/usermode/usermode/machdep.c b/sys/arch/usermode/usermode/machdep.c
index 481d4f39a4f5..189b2a7d2bce 100644
--- a/sys/arch/usermode/usermode/machdep.c
+++ b/sys/arch/usermode/usermode/machdep.c
@@ -1,4 +1,4 @@
-/* $NetBSD: machdep.c,v 1.28 2011/09/09 12:44:27 reinoud Exp $ */
+/* $NetBSD: machdep.c,v 1.29 2011/09/09 20:06:04 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2011 Reinoud Zandijk <reinoud@netbsd.org>
@@ -32,7 +32,7 @@
 #include "opt_urkelvisor.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.28 2011/09/09 12:44:27 reinoud Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.29 2011/09/09 20:06:04 reinoud Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -200,7 +200,7 @@ setregs(struct lwp *l, struct exec_package *pack, vaddr_t stack)
 
 	ucp->uc_stack.ss_sp = (void *) (stack-4);	/* to prevent clearing */
 	ucp->uc_stack.ss_size = 0; //pack->ep_ssize;
-	thunk_makecontext(ucp, (void *) pack->ep_entry, 0, NULL, NULL);
+	thunk_makecontext(ucp, (void *) pack->ep_entry, 0, NULL, NULL, NULL);
 
 	/* patch up */
 	reg[ 8] = l->l_proc->p_psstrp;	/* _REG_EBX */