diff --git a/sys/powerpc/aim/machdep.c b/sys/powerpc/aim/machdep.c
index 75b59186187e..a74cc27286e4 100644
--- a/sys/powerpc/aim/machdep.c
+++ b/sys/powerpc/aim/machdep.c
@@ -247,6 +247,7 @@ extern void	*dsitrap, *dsisize;
 extern void	*decrint, *decrsize;
 extern void     *extint, *extsize;
 extern void	*dblow, *dbsize;
+extern void	*vectrap, *vectrapsize;
 
 void
 powerpc_init(u_int startkernel, u_int endkernel, u_int basekernel, void *mdp)
@@ -335,6 +336,8 @@ powerpc_init(u_int startkernel, u_int endkernel, u_int basekernel, void *mdp)
 	bcopy(&trapcode, (void *)EXC_SC,   (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_TRC,  (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_FPA,  (size_t)&trapsize);
+	bcopy(&vectrap,  (void *)EXC_VEC,  (size_t)&vectrapsize);
+	bcopy(&trapcode, (void *)EXC_VECAST, (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_THRM, (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_BPT,  (size_t)&trapsize);
 #ifdef KDB
diff --git a/sys/powerpc/aim/trap.c b/sys/powerpc/aim/trap.c
index 669bb60b939d..85bdab95ccd1 100644
--- a/sys/powerpc/aim/trap.c
+++ b/sys/powerpc/aim/trap.c
@@ -199,6 +199,11 @@ trap(struct trapframe *frame)
 			enable_vec(td);
 			frame->srr1 |= PSL_VEC;
 			break;
+#else
+		case EXC_VEC:
+		case EXC_VECAST:
+			sig = SIGILL;
+			break;
 #endif /* ALTIVEC */
 
 		case EXC_ALI:
diff --git a/sys/powerpc/aim/trap_subr.S b/sys/powerpc/aim/trap_subr.S
index 60435dd83481..c7199171df03 100644
--- a/sys/powerpc/aim/trap_subr.S
+++ b/sys/powerpc/aim/trap_subr.S
@@ -443,6 +443,14 @@ CNAME(trapexit):
 	FRAME_LEAVE(PC_TEMPSAVE)
 	rfi
 
+/*
+ *     Temporary: vector-unavailable traps are directed to vector-assist traps
+ */
+	.globl  CNAME(vectrap),CNAME(vectrapsize)
+CNAME(vectrap):
+	ba	EXC_VECAST
+CNAME(vectrapsize) = .-CNAME(vectrap)
+
 #if defined(KDB)
 /*
  * Deliberate entry to dbtrap
diff --git a/sys/powerpc/powerpc/machdep.c b/sys/powerpc/powerpc/machdep.c
index 75b59186187e..a74cc27286e4 100644
--- a/sys/powerpc/powerpc/machdep.c
+++ b/sys/powerpc/powerpc/machdep.c
@@ -247,6 +247,7 @@ extern void	*dsitrap, *dsisize;
 extern void	*decrint, *decrsize;
 extern void     *extint, *extsize;
 extern void	*dblow, *dbsize;
+extern void	*vectrap, *vectrapsize;
 
 void
 powerpc_init(u_int startkernel, u_int endkernel, u_int basekernel, void *mdp)
@@ -335,6 +336,8 @@ powerpc_init(u_int startkernel, u_int endkernel, u_int basekernel, void *mdp)
 	bcopy(&trapcode, (void *)EXC_SC,   (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_TRC,  (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_FPA,  (size_t)&trapsize);
+	bcopy(&vectrap,  (void *)EXC_VEC,  (size_t)&vectrapsize);
+	bcopy(&trapcode, (void *)EXC_VECAST, (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_THRM, (size_t)&trapsize);
 	bcopy(&trapcode, (void *)EXC_BPT,  (size_t)&trapsize);
 #ifdef KDB
diff --git a/sys/powerpc/powerpc/trap.c b/sys/powerpc/powerpc/trap.c
index 669bb60b939d..85bdab95ccd1 100644
--- a/sys/powerpc/powerpc/trap.c
+++ b/sys/powerpc/powerpc/trap.c
@@ -199,6 +199,11 @@ trap(struct trapframe *frame)
 			enable_vec(td);
 			frame->srr1 |= PSL_VEC;
 			break;
+#else
+		case EXC_VEC:
+		case EXC_VECAST:
+			sig = SIGILL;
+			break;
 #endif /* ALTIVEC */
 
 		case EXC_ALI:
diff --git a/sys/powerpc/powerpc/trap_subr.S b/sys/powerpc/powerpc/trap_subr.S
index 60435dd83481..c7199171df03 100644
--- a/sys/powerpc/powerpc/trap_subr.S
+++ b/sys/powerpc/powerpc/trap_subr.S
@@ -443,6 +443,14 @@ CNAME(trapexit):
 	FRAME_LEAVE(PC_TEMPSAVE)
 	rfi
 
+/*
+ *     Temporary: vector-unavailable traps are directed to vector-assist traps
+ */
+	.globl  CNAME(vectrap),CNAME(vectrapsize)
+CNAME(vectrap):
+	ba	EXC_VECAST
+CNAME(vectrapsize) = .-CNAME(vectrap)
+
 #if defined(KDB)
 /*
  * Deliberate entry to dbtrap