arm64: show unhandled SP/PC alignment faults

Report unhandled SP/PC alignment faults if the show_unhandled_signals
variable is set (via /proc/sys/debug/exception-trace).
Signed-off-by: NVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

arch/arm64/mm/fault.c

@@ -478,12 +478,19 @@ asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
 					   struct pt_regs *regs)
 {
 	struct siginfo info;
+	struct task_struct *tsk = current;
+
+	if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS))
+		pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n",
+				    tsk->comm, task_pid_nr(tsk),
+				    esr_get_class_string(esr), (void *)regs->pc,
+				    (void *)regs->sp);
 
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code  = BUS_ADRALN;
 	info.si_addr  = (void __user *)addr;
-	arm64_notify_die("", regs, &info, esr);
+	arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr);
 }
 
 static struct fault_info debug_fault_info[] = {