ptrace/m68k: Stop open coding ptrace_report_syscall

The generic function ptrace_report_syscall does a little more
than syscall_trace on m68k.  The function ptrace_report_syscall
stops early if PT_TRACED is not set, it sets ptrace_message,
and returns the result of fatal_signal_pending.

Setting ptrace_message to a passed in value of 0 is effectively not
setting ptrace_message, making that additional work a noop.

Returning the result of fatal_signal_pending and letting the caller
ignore the result becomes a noop in this change.

When a process is ptraced, the flag PT_PTRACED is always set in
current->ptrace.  Testing for PT_PTRACED in ptrace_report_syscall is
just an optimization to fail early if the process is not ptraced.
Later on in ptrace_notify, ptrace_stop will test current->ptrace under
tasklist_lock and skip performing any work if the task is not ptraced.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lkml.kernel.org/r/20220103213312.9144-8-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Author: ebiederm

arch/m68k/kernel/ptrace.c

@@ -273,17 +273,7 @@ long arch_ptrace(struct task_struct *child, long request,
 
 asmlinkage void syscall_trace(void)
 {
-	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-				 ? 0x80 : 0));
-	/*
-	 * this isn't the same as continuing with a signal, but it will do
-	 * for normal use.  strace only continues with a signal if the
-	 * stopping signal is not SIGTRAP.  -brl
-	 */
-	if (current->exit_code) {
-		send_sig(current->exit_code, current, 1);
-		current->exit_code = 0;
-	}
+	ptrace_report_syscall(0);
 }
 
 #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)