kernel: Init back pointer to microkernel task

Fibers initialize this back pointer to NULL as they are (by definition)
not microkernel tasks.  Microkernel tasks initialize it to their
corresponding 'ktask_t'.

However for nanokernel systems, the back pointer is always NULL. This
is because there is only one task in a nanokernel system (the background
task) and it can not pend on a nanokernel object--it must poll.

Change-Id: I9840fecc44224bef63d09d587d703720cf33ad57
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>

arch/arc/core/thread.c

@@ -101,7 +101,8 @@ static ALWAYS_INLINE void thread_monitor_init(struct tcs *tcs)
  *
  * @return N/A
  */
-void _new_thread(char *pStackMem, unsigned stackSize, _thread_entry_t pEntry,
+void _new_thread(char *pStackMem, unsigned stackSize,
+		 void *uk_task_ptr, _thread_entry_t pEntry,
 		 void *parameter1, void *parameter2, void *parameter3,
 		 int priority, unsigned options)
 {
@@ -154,6 +155,13 @@ void _new_thread(char *pStackMem, unsigned stackSize, _thread_entry_t pEntry,
 	 */
 	tcs->entry = (struct __thread_entry *)(pInitCtx);
 #endif
+
+#ifdef CONFIG_MICROKERNEL
+	tcs->uk_task_ptr = uk_task_ptr;
+#else
+	ARG_UNUSED(uk_task_ptr);
+#endif
+
 	/*
 	 * intlock_key is constructed based on ARCv2 ISA Programmer's
 	 * Reference Manual CLRI instruction description:

arch/arm/core/thread.c

@@ -100,7 +100,8 @@ static ALWAYS_INLINE void _thread_monitor_init(struct tcs *tcs /* thread */
  * @return N/A
  */
 
-void _new_thread(char *pStackMem, unsigned stackSize, _thread_entry_t pEntry,
+void _new_thread(char *pStackMem, unsigned stackSize,
+		 void *uk_task_ptr, _thread_entry_t pEntry,
 		 void *parameter1, void *parameter2, void *parameter3,
 		 int priority, unsigned options)
 {
@@ -143,6 +144,12 @@ void _new_thread(char *pStackMem, unsigned stackSize, _thread_entry_t pEntry,
 	tcs->entry = (struct __thread_entry *)(pInitCtx);
 #endif
 
+#ifdef CONFIG_MICROKERNEL
+	tcs->uk_task_ptr = uk_task_ptr;
+#else
+	ARG_UNUSED(uk_task_ptr);
+#endif
+
 	tcs->preempReg.psp = (uint32_t)pInitCtx;
 	tcs->basepri = 0;
 

arch/x86/core/i386_sysV_abi/thread.c

@@ -64,7 +64,7 @@ void _thread_entry_wrapper(_thread_entry_t, _thread_arg_t,
  * @return N/A
  */
 static void _new_thread_internal(char *pStackMem, unsigned stackSize,
-				 int priority, unsigned options)
+				 void *uk_task_ptr, int priority, unsigned options)
 {
 	unsigned long *pInitialCtx;
 	/* ptr to the new task's tcs */
@@ -92,6 +92,11 @@ static void _new_thread_internal(char *pStackMem, unsigned stackSize,
 	tcs->custom_data = NULL;
 #endif
 
+#ifdef CONFIG_MICROKERNEL
+	tcs->uk_task_ptr = uk_task_ptr;
+#else
+	ARG_UNUSED(uk_task_ptr);
+#endif
 
 	/*
 	 * The creation of the initial stack for the task has already been done.
@@ -287,7 +292,8 @@ __asm__("\t.globl _thread_entry\n"
  *
  * @return opaque pointer to initialized TCS structure
  */
-void _new_thread(char *pStackMem, unsigned stackSize, _thread_entry_t pEntry,
+void _new_thread(char *pStackMem, unsigned stackSize,
+		 void *uk_task_ptr, _thread_entry_t pEntry,
 		 void *parameter1, void *parameter2, void *parameter3,
 		 int priority, unsigned options)
 {
@@ -347,5 +353,5 @@ void _new_thread(char *pStackMem, unsigned stackSize, _thread_entry_t pEntry,
 	 * is located at the "low end" of memory set aside for the thread's stack.
 	 */
 
-	_new_thread_internal(pStackMem, stackSize, priority, options);
+	_new_thread_internal(pStackMem, stackSize, uk_task_ptr, priority, options);
 }

arch/x86/core/iamcu_abi/thread.c

@@ -60,9 +60,9 @@ void _thread_entry_wrapper(_thread_entry_t, _thread_arg_t,
  */
 
 void _new_thread(char *stack_memory, unsigned stack_size,
-		 _thread_entry_t thread_func, void *parameter1,
+		 void *uk_task_ptr, _thread_entry_t thread_func,
-		 void *parameter2, void *parameter3, int priority,
+		 void *parameter1, void *parameter2, void *parameter3,
-		 unsigned options)
+		 int priority, unsigned options)
 {
 	unsigned long *thread_context;
 	struct tcs *tcs = (struct tcs *)stack_memory;
@@ -118,6 +118,11 @@ void _new_thread(char *stack_memory, unsigned stack_size,
 	*thread_context = (unsigned long)(thread_context + 4);
 	*--thread_context = 0;
 
+#ifdef CONFIG_MICROKERNEL
+	tcs->uk_task_ptr = uk_task_ptr;
+#else
+	ARG_UNUSED(uk_task_ptr);
+#endif
 	tcs->coopReg.esp = (unsigned long)thread_context;
 #if defined(CONFIG_THREAD_MONITOR)
 	{

kernel/microkernel/k_task.c

@@ -206,6 +206,7 @@ static void start_task(struct k_task *X, void (*func)(void))
 
 	_new_thread((char *)X->workspace, /* pStackMem */
 			X->worksize,		/* stackSize */
+			X,                  /* microkernel task pointer */
 			(_thread_entry_t)func,  /* pEntry */
 			parameter1,		/* parameter1 */
 			(void *)0,		/* parameter2 */

kernel/nanokernel/include/nano_internal.h

@@ -48,8 +48,9 @@ extern void _thread_entry(_thread_entry_t,
 			     _thread_arg_t);
 
 extern void _new_thread(char *pStack, unsigned stackSize,
-						_thread_entry_t pEntry, _thread_arg_t arg1,
+						void *uk_task_ptr, _thread_entry_t pEntry,
-						_thread_arg_t arg2, _thread_arg_t arg3,
+						_thread_arg_t arg1, _thread_arg_t arg2,
+						_thread_arg_t arg3,
 						int prio, unsigned options);
 
 /* context switching and scheduling-related routines */

kernel/nanokernel/nano_fiber.c

@@ -81,6 +81,7 @@ nano_thread_id_t _fiber_start(char *pStack,
 	tcs = (struct tcs *) pStack;
 	_new_thread(pStack,
 			stackSize,
+			NULL,
 			(_thread_entry_t)pEntry,
 			(void *)parameter1,
 			(void *)parameter2,
@@ -193,7 +194,7 @@ nano_thread_id_t fiber_delayed_start(char *stack,
 	struct tcs *tcs;
 
 	tcs = (struct tcs *)stack;
-	_new_thread(stack, stack_size_in_bytes, (_thread_entry_t)entry_point,
+	_new_thread(stack, stack_size_in_bytes, NULL, (_thread_entry_t)entry_point,
 		(void *)param1, (void *)param2, (void *)0, priority, options);
 
 	key = irq_lock();

kernel/nanokernel/nano_init.c

@@ -93,6 +93,9 @@ char __noinit _interrupt_stack[CONFIG_ISR_STACK_SIZE];
 #endif
 
 #ifdef CONFIG_NANOKERNEL
+
+#define MICROKERNEL_IDLE_TASK_PTR  (NULL)
+
 /**
  *
  * @brief Mainline for nanokernel's background task
@@ -120,6 +123,13 @@ static void _main(void)
 	main();
 }
 #else
+
+typedef int32_t ktask_t;   /* Must match definition in base_api.h */
+
+extern ktask_t _k_task_ptr_idle;
+
+#define MICROKERNEL_IDLE_TASK_PTR  ((void *) _k_task_ptr_idle)
+
 /* microkernel has its own implementation of _main() */
 
 extern void _main(void);
@@ -178,6 +188,7 @@ static void nano_init(struct tcs *dummyOutContext)
 
 	_new_thread(main_task_stack,	/* pStackMem */
 			    CONFIG_MAIN_STACK_SIZE, /* stackSize */
+			    MICROKERNEL_IDLE_TASK_PTR, /* ptr to idle task */
 			    (_thread_entry_t)_main,	 /* pEntry */
 			    (_thread_arg_t)0,	 /* parameter1 */
 			    (_thread_arg_t)0,	 /* parameter2 */