ARC: Show fault information passed to show_kernel_fault_diag()

Currently we pass a string argument to show_kernel_fault_diag() which
describes the reason for the fault. This is not being used so just
add a pr_info() which outputs the fault information.

With this change we get from:

|
| Path: /bin/busybox
| CPU: 0 PID: 92 Comm: modprobe Not tainted 4.12.0-rc6 #30
| task: 9a254780 task.stack: 9a212000
|
| [ECR   ]: 0x00200400 => Other Fatal Err
|

to:

|
| Unhandled Machine Check Exception
| Path: /bin/busybox
| CPU: 0 PID: 92 Comm: modprobe Not tainted 4.12.0-rc6 #37
| task: 9a240780 task.stack: 9a226000
|
|[ECR   ]: 0x00200400 => Machine Check (Other Fatal Err)
|

Which can help debugging.

Cc: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

2 files changed, 5 insertions, 2 deletions

diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
index 62675b94fccd..bcd7c9fc5d0f 100644
--- a/arch/arc/kernel/traps.c
+++ b/arch/arc/kernel/traps.c
@@ -103,7 +103,7 @@ int do_misaligned_access(unsigned long address, struct pt_regs *regs,
  */
 void do_machine_check_fault(unsigned long address, struct pt_regs *regs)
 {
-        die("Machine Check Exception", regs, address);
+        die("Unhandled Machine Check Exception", regs, address);
 }
 
 
diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
index f9caf79186d4..7e94476f3994 100644
--- a/arch/arc/kernel/troubleshoot.c
+++ b/arch/arc/kernel/troubleshoot.c
@@ -140,7 +140,7 @@ static void show_ecr_verbose(struct pt_regs *regs)
         } else if (vec == ECR_V_ITLB_MISS) {
                 pr_cont("Insn could not be fetched\n");
         } else if (vec == ECR_V_MACH_CHK) {
-                pr_cont("%s\n", (cause_code == 0x0) ?
+                pr_cont("Machine Check (%s)\n", (cause_code == 0x0) ?
                                         "Double Fault" : "Other Fatal Err");
 
         } else if (vec == ECR_V_PROTV) {
@@ -233,6 +233,9 @@ void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 {
         current->thread.fault_address = address;
 
+        /* Show fault description */
+        pr_info("\n%s\n", str);
+
         /* Caller and Callee regs */
         show_regs(regs);