microblaze: use generic ptrace_resume code

Use the generic ptrace_resume code for PTRACE_SYSCALL, PTRACE_CONT and
PTRACE_KILL.  This also makes PTRACE_SINGLESTEP return -EIO while it
previously succeeded despite not actually causing any kind of single
stepping.

Also the TIF_SYSCALL_TRACE thread flag is now cleared on PTRACE_KILL which
it previously wasn't which is consistent with all architectures using the
modern ptrace code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Acked-by: Michal Simek <monstr@monstr.eu>
Cc: John Williams <john.williams@petalogix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/microblaze/kernel/ptrace.c

@@ -110,43 +110,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		if (rval == 0 && request == PTRACE_PEEKUSR)
 			rval = put_user(val, (unsigned long *)data);
 		break;
-	/* Continue and stop at next (return from) syscall */
-	case PTRACE_SYSCALL:
-		pr_debug("PTRACE_SYSCALL\n");
-	case PTRACE_SINGLESTEP:
-		pr_debug("PTRACE_SINGLESTEP\n");
-	/* Restart after a signal.  */
-	case PTRACE_CONT:
-		pr_debug("PTRACE_CONT\n");
-		rval = -EIO;
-		if (!valid_signal(data))
-			break;
-
-		if (request == PTRACE_SYSCALL)
-			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-		else
-			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-
-		child->exit_code = data;
-		pr_debug("wakeup_process\n");
-		wake_up_process(child);
-		rval = 0;
-		break;
-
-	/*
-	 * make the child exit.  Best I can do is send it a sigkill.
-	 * perhaps it should be put in the status that it wants to
-	 * exit.
-	 */
-	case PTRACE_KILL:
-		pr_debug("PTRACE_KILL\n");
-		rval = 0;
-		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
-			break;
-		child->exit_code = SIGKILL;
-		wake_up_process(child);
-		break;
-
 	default:
 		rval = ptrace_request(child, request, addr, data);
 	}