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>

2 files changed, 12 insertions, 1 deletions

diff --git a/arch/blackfin/kernel/setup.c b/arch/blackfin/kernel/setup.c
index 2ae84fea89eb..eb300550e093 100644
--- a/arch/blackfin/kernel/setup.c
+++ b/arch/blackfin/kernel/setup.c
@@ -52,6 +52,7 @@ EXPORT_SYMBOL(mtd_size);
 #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 @@ void __init setup_arch(char **cmdline_p)
         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 2c69ad49894e..fb7e2d426999 100644
--- a/arch/blackfin/mach-common/head.S
+++ b/arch/blackfin/mach-common/head.S
@@ -90,6 +90,12 @@ ENTRY(__start)
         [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;