Blackfin arch: Print out doublefault addresses, so debug can occur

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/arch/blackfin/mach-common/head.S b/arch/blackfin/mach-common/head.S
index 2c69ad4..fb7e2d4 100644
--- a/arch/blackfin/mach-common/head.S
+++ b/arch/blackfin/mach-common/head.S
@@ -90,6 +90,12 @@
 	[p0] = R0;
 	SSYNC;
 
+	/* Save RETX, in case of doublefault */
+	p0.l = ___retx;
+	p0.h = ___retx;
+	R0 = RETX;
+	[P0] = R0;
+
 	/* Let each Blackfin family do its own thing */
 	call _mach_early_start;