Index: kernel/arch/ppc32/src/asm.S
===================================================================
--- kernel/arch/ppc32/src/asm.S	(revision 7560b606cea3b9fdec24aa6444d3e37011f2d025)
+++ kernel/arch/ppc32/src/asm.S	(revision 0d387d2adba60bc09a047a4aeb5fe9c90f7ad2cc)
@@ -66,4 +66,8 @@
 	
 	mr sp, r4
+
+	# %r3 is defined to hold pcb_ptr - set it to 0
+
+	xor r3, r3, r3
 	
 	# jump to userspace