--- zzzz-none-000/linux-2.6.19.2/arch/powerpc/kernel/signal_64.c	2007-01-10 19:10:37.000000000 +0000
+++ davinci-8020-5504/linux-2.6.19.2/arch/powerpc/kernel/signal_64.c	2007-01-19 14:42:56.000000000 +0000
@@ -397,7 +397,7 @@
 	current->thread.fpscr.val = 0;
 
 	/* Set up to return from userspace. */
-	if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
+	if (vdso64_rt_sigtramp && current->mm->context.vdso_base != ~0UL) {
 		regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
 	} else {
 		err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);