sched/rt, xtensa: Use CONFIG_PREEMPTION

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the entry code over to use CONFIG_PREEMPTION. Add PREEMPT_RT
output to die().

[bigeasy: +traps.c]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-xtensa@linux-xtensa.org
Link: https://lore.kernel.org/r/20191015191821.11479-21-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/xtensa/kernel/entry.S

@@ -520,7 +520,7 @@ common_exception_return:
 	call4	schedule	# void schedule (void)
 	j	1b
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 6:
 	_bbci.l	a4, TIF_NEED_RESCHED, 4f
 

arch/xtensa/kernel/traps.c

@@ -519,12 +519,15 @@ DEFINE_SPINLOCK(die_lock);
 void die(const char * str, struct pt_regs * regs, long err)
 {
 	static int die_counter;
+	const char *pr = "";
+
+	if (IS_ENABLED(CONFIG_PREEMPTION))
+		pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
 
 	console_verbose();
 	spin_lock_irq(&die_lock);
 
-	pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter,
-		IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "");
+	pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter, pr);
 	show_regs(regs);
 	if (!user_mode(regs))
 		show_stack(NULL, (unsigned long*)regs->areg[1]);