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/kernel/setup.c b/arch/blackfin/kernel/setup.c
index 2ae84fe..eb30055 100644
--- a/arch/blackfin/kernel/setup.c
+++ b/arch/blackfin/kernel/setup.c
@@ -52,6 +52,7 @@
 #endif
 
 char __initdata command_line[COMMAND_LINE_SIZE];
+unsigned int __initdata *__retx;
 
 /* boot memmap, for parsing "memmap=" */
 #define BFIN_MEMMAP_MAX		128 /* number of entries in bfin_memmap */
@@ -785,7 +786,11 @@
 	bfin_write_SWRST(DOUBLE_FAULT);
 
 	if (_bfin_swrst & RESET_DOUBLE)
-		printk(KERN_INFO "Recovering from Double Fault event\n");
+		/*
+		 * don't decode the address, since you don't know if this
+		 * kernel's symbol map is the same as the crashing kernel
+		 */
+		printk(KERN_INFO "Recovering from Double Fault event at %p\n", __retx);
 	else if (_bfin_swrst & RESET_WDOG)
 		printk(KERN_INFO "Recovering from Watchdog event\n");
 	else if (_bfin_swrst & RESET_SOFTWARE)
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;