kernel: move thread monitor init to common code

The original implementation of CONFIG_THREAD_MONITOR would
try to leverage a thread's initial stack layout to provide
the entry function with arguments for any given thread.

This is problematic:

- Some arches do not have a initial stack layout suitable for
this
- Some arches never enabled this at all (riscv32, nios2)
- Some arches did not enable this properly
- Dropping to user mode would erase or provide incorrect
information.

Just spend a few extra bytes to store this stuff directly
in the k_thread struct and get rid of all the arch-specific
code for this.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>

arch/arc/core/thread.c

@@ -174,15 +174,6 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 		thread->arch.priv_stack_size = 0;
 	}
 #endif
-
-#ifdef CONFIG_THREAD_MONITOR
-	/*
-	 * In debug mode thread->entry give direct access to the thread entry
-	 * and the corresponding parameters.
-	 */
-	thread->entry = (struct __thread_entry *)(pInitCtx);
-#endif
-
 	/*
 	 * intlock_key is constructed based on ARCv2 ISA Programmer's
 	 * Reference Manual CLRI instruction description:
@@ -195,8 +186,6 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 		(u32_t)pInitCtx - ___callee_saved_stack_t_SIZEOF;
 
 	/* initial values in all other regs/k_thread entries are irrelevant */
-
-	thread_monitor_init(thread);
 }
 
 

arch/arm/core/thread.c

@@ -68,27 +68,10 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 	char *stackEnd = pStackMem + stackSize;
 #endif
 	struct __esf *pInitCtx;
-#ifdef CONFIG_THREAD_MONITOR
-	struct __thread_entry *pMon;
-#endif
 
 	_new_thread_init(thread, pStackMem, stackEnd - pStackMem, priority,
 			 options);
 
-#ifdef CONFIG_THREAD_MONITOR
-	pMon = (struct __thread_entry *)
-		STACK_ROUND_DOWN(stackEnd - sizeof(struct __thread_entry));
-	pMon->pEntry = pEntry;
-	pMon->parameter1 = parameter1;
-	pMon->parameter2 = parameter2;
-	pMon->parameter3 = parameter3;
-
-	thread->entry = pMon;
-	thread_monitor_init(thread);
-
-	stackEnd = (char *)pMon;
-#endif
-
 	/* carve the thread entry struct from the "base" of the stack */
 	pInitCtx = (struct __esf *)(STACK_ROUND_DOWN(stackEnd -
 						     sizeof(struct __esf)));

arch/nios2/core/thread.c

@@ -57,6 +57,4 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 	thread->callee_saved.ra = (u32_t)_thread_entry_wrapper;
 	thread->callee_saved.key = NIOS2_STATUS_PIE_MSK;
 	/* Leave the rest of thread->callee_saved junk */
-
-	thread_monitor_init(thread);
 }

arch/posix/core/thread.c

@@ -77,10 +77,7 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 
 	thread->callee_saved.thread_status = (u32_t)thread_status;
 
-
 	posix_new_thread(thread_status);
-
-	thread_monitor_init(thread);
 }
 
 void posix_new_thread_pre_start(void)

arch/riscv32/core/thread.c

@@ -64,6 +64,4 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 	stack_init->mepc = (u32_t)_thread_entry_wrapper;
 
 	thread->callee_saved.sp = (u32_t)stack_init;
-
-	thread_monitor_init(thread);
 }

arch/x86/core/thread.c

@@ -124,10 +124,6 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 #if defined(CONFIG_FP_SHARING)
 	thread->arch.excNestCount = 0;
 #endif /* CONFIG_FP_SHARING */
-#ifdef CONFIG_THREAD_MONITOR
-	thread->entry = (struct __thread_entry *)&initial_frame->entry;
-	thread_monitor_init(thread);
-#endif
 }
 
 #ifdef CONFIG_X86_USERSPACE

arch/xtensa/core/thread.c

@@ -118,17 +118,8 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack,
 #endif
 	thread->callee_saved.topOfStack = pInitCtx;
 	thread->arch.flags = 0;
-#ifdef CONFIG_THREAD_MONITOR
-	/*
-	 * In debug mode thread->entry give direct access to the thread entry
-	 * and the corresponding parameters.
-	 */
-	thread->entry = (struct __thread_entry *)(pInitCtx);
-#endif
 	/* initial values in all other registers/k_thread entries are
 	 * irrelevant
 	 */
-
-	thread_monitor_init(thread);
 }
 

arch/xtensa/core/xtensa-asm2.c

@@ -71,15 +71,6 @@ void _new_thread(struct k_thread *thread, k_thread_stack_t *stack, size_t sz,
 
 	_new_thread_init(thread, base, sz, prio, opts);
 
-#ifdef CONFIG_THREAD_MONITOR
-	top -= sizeof(struct __thread_entry);
-	thread->entry = (void *)top;
-	thread->entry->pEntry = entry;
-
-	thread_monitor_init(thread);
-#endif
-
-
 	thread->switch_handle = xtensa_init_stack((void *)top, entry,
 						  p1, p2, p3);
 }

arch/xtensa/include/kernel_arch_thread.h

@@ -110,13 +110,6 @@ struct _thread_arch {
 #ifdef CONFIG_THREAD_CUSTOM_DATA
 	void *custom_data;     /* available for custom use */
 #endif
-#if defined(CONFIG_THREAD_MONITOR)
-	/* thread entry and parameters description */
-	struct __thread_entry *entry;
-
-	/* next item in list of ALL threads n*/
-	struct k_thread *next_thread;
-#endif
 #ifdef CONFIG_ERRNO
 	int errno_var;
 #endif

include/kernel.h

@@ -546,7 +546,7 @@ struct k_thread {
 
 #if defined(CONFIG_THREAD_MONITOR)
 	/** thread entry and parameters description */
-	struct __thread_entry *entry;
+	struct __thread_entry entry;
 
 	/** next item in list of all threads */
 	struct k_thread *next_thread;

kernel/include/kernel_structs.h

@@ -247,25 +247,6 @@ static ALWAYS_INLINE void _new_thread_init(struct k_thread *thread,
 #endif /* CONFIG_THREAD_STACK_INFO */
 }
 
-#if defined(CONFIG_THREAD_MONITOR)
-/*
- * Add a thread to the kernel's list of active threads.
- */
-static ALWAYS_INLINE void thread_monitor_init(struct k_thread *thread)
-{
-	unsigned int key;
-
-	key = irq_lock();
-	thread->next_thread = _kernel.threads;
-	_kernel.threads = thread;
-	irq_unlock(key);
-}
-#else
-#define thread_monitor_init(thread)		\
-	do {/* do nothing */			\
-	} while ((0))
-#endif /* CONFIG_THREAD_MONITOR */
-
 #endif /* _ASMLANGUAGE */
 
 #endif /* _kernel_structs__h_ */

kernel/thread.c

@@ -298,6 +298,18 @@ void _setup_new_thread(struct k_thread *new_thread,
 
 	_new_thread(new_thread, stack, stack_size, entry, p1, p2, p3,
 		    prio, options);
+#ifdef CONFIG_THREAD_MONITOR
+	new_thread->entry.pEntry = entry;
+	new_thread->entry.parameter1 = p1;
+	new_thread->entry.parameter2 = p2;
+	new_thread->entry.parameter3 = p3;
+
+	int key = irq_lock();
+
+	new_thread->next_thread = _kernel.threads;
+	_kernel.threads = new_thread;
+	irq_unlock(key);
+#endif
 #ifdef CONFIG_USERSPACE
 	_k_object_init(new_thread);
 	_k_object_init(stack);
@@ -641,6 +653,12 @@ FUNC_NORETURN void k_thread_user_mode_enter(k_thread_entry_t entry,
 {
 	_current->base.user_options |= K_USER;
 	_thread_essential_clear();
+#ifdef CONFIG_THREAD_MONITOR
+	_current->entry.pEntry = entry;
+	_current->entry.parameter1 = p1;
+	_current->entry.parameter2 = p2;
+	_current->entry.parameter3 = p3;
+#endif
 #ifdef CONFIG_USERSPACE
 	_arch_user_mode_enter(entry, p1, p2, p3);
 #else

samples/subsys/debug/sysview/src/main.c

@@ -99,7 +99,7 @@ static void sysview_api_send_task(const struct k_thread *thr, void *udata)
 	char name[20];
 
 	snprintk(name, sizeof(name), "T%xE%x",
-			(uintptr_t)thr, (uintptr_t)thr->entry);
+			(uintptr_t)thr, (uintptr_t)(&thr->entry));
 
 	/* NOTE: struct k_thread is inside the stack on Zephyr 1.7.
 	 * This is not guaranteed by the API, and is likely to change