Blackfin arch: add supporting for double fault debug handling

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 30 insertions, 4 deletions

diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index fd24e04fc19e..bd41fca315dd 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -68,7 +68,15 @@ void __init trap_init(void)
         CSYNC();
 }
 
-unsigned long saved_icplb_fault_addr, saved_dcplb_fault_addr;
+/*
+ * Used to save the RETX, SEQSTAT, I/D CPLB FAULT ADDR
+ * values across the transition from exception to IRQ5.
+ * We put these in L1, so they are going to be in a valid
+ * location during exception context
+ */
+__attribute__((l1_data))
+unsigned long saved_retx, saved_seqstat,
+        saved_icplb_fault_addr, saved_dcplb_fault_addr;
 
 static void decode_address(char *buf, unsigned long address)
 {
@@ -186,9 +194,27 @@ asmlinkage void double_fault_c(struct pt_regs *fp)
         console_verbose();
         oops_in_progress = 1;
         printk(KERN_EMERG "\n" KERN_EMERG "Double Fault\n");
-        dump_bfin_process(fp);
-        dump_bfin_mem(fp);
-        show_regs(fp);
+#ifdef CONFIG_DEBUG_DOUBLEFAULT_PRINT
+        if (((long)fp->seqstat &  SEQSTAT_EXCAUSE) == VEC_UNCOV) {
+                char buf[150];
+                decode_address(buf, saved_retx);
+                printk(KERN_EMERG "While handling exception (EXCAUSE = 0x%x) at %s:\n",
+                        (int)saved_seqstat & SEQSTAT_EXCAUSE, buf);
+                decode_address(buf, saved_dcplb_fault_addr);
+                printk(KERN_NOTICE "   DCPLB_FAULT_ADDR: %s\n", buf);
+                decode_address(buf, saved_icplb_fault_addr);
+                printk(KERN_NOTICE "   ICPLB_FAULT_ADDR: %s\n", buf);
+
+                decode_address(buf, fp->retx);
+                printk(KERN_NOTICE "The instruction at %s caused a double exception\n",
+                        buf);
+        } else
+#endif
+        {
+                dump_bfin_process(fp);
+                dump_bfin_mem(fp);
+                show_regs(fp);
+        }
         panic("Double Fault - unrecoverable event\n");
 
 }