diff --git a/sys/arch/arm/arm/sig_machdep.c b/sys/arch/arm/arm/sig_machdep.c
index f85731c75e4e..8d715969bac3 100644
--- a/sys/arch/arm/arm/sig_machdep.c
+++ b/sys/arch/arm/arm/sig_machdep.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: sig_machdep.c,v 1.48 2014/08/13 21:10:31 matt Exp $	*/
+/*	$NetBSD: sig_machdep.c,v 1.49 2015/03/24 08:38:29 matt Exp $	*/
 
 /*
  * Copyright (c) 1994-1998 Mark Brinicombe.
@@ -44,7 +44,7 @@
 
 #include <sys/param.h>
 
-__KERNEL_RCSID(0, "$NetBSD: sig_machdep.c,v 1.48 2014/08/13 21:10:31 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sig_machdep.c,v 1.49 2015/03/24 08:38:29 matt Exp $");
 
 #include <sys/mount.h>		/* XXX only needed by syscallargs.h */
 #include <sys/cpu.h>
@@ -199,6 +199,11 @@ cpu_getmcontext(struct lwp *l, mcontext_t *mcp, unsigned int *flags)
 
 	mcp->_mc_tlsbase = (uintptr_t)l->l_private;
 	*flags |= _UC_TLSBASE;
+
+#ifdef __PROG32
+	const struct pcb * const pcb = lwp_getpcb(l);
+	mcp->_mc_user_tpid = pcb->pcb_user_pid_rw;
+#endif
 }
 
 int
@@ -268,5 +273,10 @@ cpu_setmcontext(struct lwp *l, const mcontext_t *mcp, unsigned int flags)
 		l->l_sigstk.ss_flags &= ~SS_ONSTACK;
 	mutex_exit(p->p_lock);
 
+#ifdef __PROG32
+	struct pcb * const pcb = lwp_getpcb(l);
+	pcb->pcb_user_pid_rw = mcp->_mc_user_tpid;
+#endif
+
 	return (0);
 }
diff --git a/sys/arch/arm/include/mcontext.h b/sys/arch/arm/include/mcontext.h
index 12d1acc739e9..d0d0cc1cd3b8 100644
--- a/sys/arch/arm/include/mcontext.h
+++ b/sys/arch/arm/include/mcontext.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: mcontext.h,v 1.17 2015/03/18 21:02:47 joerg Exp $	*/
+/*	$NetBSD: mcontext.h,v 1.18 2015/03/24 08:38:29 matt Exp $	*/
 
 /*-
  * Copyright (c) 2001, 2002 The NetBSD Foundation, Inc.
@@ -95,6 +95,7 @@ typedef struct {
 		__vfpregset_t __vfpregs;
 	} __fpu;
 	__greg_t	_mc_tlsbase;
+	__greg_t	_mc_user_tpid;
 } mcontext_t, mcontext32_t;
 
 /* Machine-dependent uc_flags */
@@ -106,7 +107,7 @@ typedef struct {
 
 #define	_UC_TLSBASE	0x00080000
 
-#define _UC_MACHINE_PAD	2		/* Padding appended to ucontext_t */
+#define _UC_MACHINE_PAD	1		/* Padding appended to ucontext_t */
 
 #define _UC_MACHINE_SP(uc)	((uc)->uc_mcontext.__gregs[_REG_SP])
 #define _UC_MACHINE_PC(uc)	((uc)->uc_mcontext.__gregs[_REG_PC])