kernel: remove checking for TIF_NOTIFY_SIGNAL

It's available everywhere now, no need to check or add dummy defines.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

include/linux/entry-common.h

@@ -37,10 +37,6 @@
 # define _TIF_UPROBE			(0)
 #endif
 
-#ifndef _TIF_NOTIFY_SIGNAL
-# define _TIF_NOTIFY_SIGNAL		(0)
-#endif
-
 /*
  * TIF flags handled in syscall_enter_from_user_mode()
  */

include/linux/sched/signal.h

@@ -360,7 +360,6 @@ static inline int task_sigpending(struct task_struct *p)
 
 static inline int signal_pending(struct task_struct *p)
 {
-#if defined(TIF_NOTIFY_SIGNAL)
 	/*
 	 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
 	 * behavior in terms of ensuring that we break out of wait loops
@@ -368,7 +367,6 @@ static inline int signal_pending(struct task_struct *p)
 	 */
 	if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
 		return 1;
-#endif
 	return task_sigpending(p);
 }
 

include/linux/tracehook.h

@@ -205,12 +205,10 @@ static inline void tracehook_notify_resume(struct pt_regs *regs)
  */
 static inline void tracehook_notify_signal(void)
 {
-#if defined(TIF_NOTIFY_SIGNAL)
 	clear_thread_flag(TIF_NOTIFY_SIGNAL);
 	smp_mb__after_atomic();
 	if (current->task_works)
 		task_work_run();
-#endif
 }
 
 /*
@@ -218,11 +216,9 @@ static inline void tracehook_notify_signal(void)
  */
 static inline void set_notify_signal(struct task_struct *task)
 {
-#if defined(TIF_NOTIFY_SIGNAL)
 	if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
 	    !wake_up_state(task, TASK_INTERRUPTIBLE))
 		kick_process(task);
-#endif
 }
 
 #endif	/* <linux/tracehook.h> */

kernel/signal.c

@@ -2535,14 +2535,12 @@ bool get_signal(struct ksignal *ksig)
 	 * that the arch handlers don't all have to do it. If we get here
 	 * without TIF_SIGPENDING, just exit after running signal work.
 	 */
-#ifdef TIF_NOTIFY_SIGNAL
 	if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) {
 		if (test_thread_flag(TIF_NOTIFY_SIGNAL))
 			tracehook_notify_signal();
 		if (!task_sigpending(current))
 			return false;
 	}
-#endif
 
 	if (unlikely(uprobe_deny_signal()))
 		return false;