kernel: Add halt_queue field to k_thread

The halt queue will be used to identify threads that are waiting
for a thread on another CPU to finish suspending.

Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>

include/zephyr/kernel/thread.h

@@ -351,6 +351,11 @@ struct k_thread {
 	struct k_obj_core  obj_core;
 #endif
 
+#ifdef CONFIG_SMP
+	/** threads waiting in k_thread_suspend() */
+	_wait_q_t  halt_queue;
+#endif
+
 	/** arch-specifics: must always be at the end */
 	struct _thread_arch arch;
 };

kernel/thread.c

@@ -681,6 +681,10 @@ char *z_setup_new_thread(struct k_thread *new_thread,
 #endif
 	new_thread->resource_pool = _current->resource_pool;
 
+#ifdef CONFIG_SMP
+	z_waitq_init(&new_thread->halt_queue);
+#endif
+
 #ifdef CONFIG_SCHED_THREAD_USAGE
 	new_thread->base.usage = (struct k_cycle_stats) {};
 	new_thread->base.usage.track_usage =