Index: kernel/arch/sparc64/src/trap/sun4v/trap_table.S
===================================================================
--- kernel/arch/sparc64/src/trap/sun4v/trap_table.S	(revision 3349e7d16f3f85b23fba328a563df72e16cc4476)
+++ kernel/arch/sparc64/src/trap/sun4v/trap_table.S	(revision 21373712dcb166726b19fe28f109a3aa73a8e68e)
@@ -897,5 +897,15 @@
 	brnz %g3, 2f
 	nop
+	rdpr %otherwin, %g4
+	brnz %g4, 1f
+	nop
+
+	/* OTHERWIN is zero, we are spilling a kernel window. */
 	INLINE_SPILL %g3, %g4
+	ba,a %xcc, 2f
+
+1:
+	/* OTHERWIN is non-zero, we are spilling a uspace window. */
+	INLINE_SPILL_TO_WBUF %g3, %g4, %g7
 
 2: