[Feature]add MT2731_MP2_MR2_SVN388 baseline version

Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/bsp/lk/kernel/thread.c b/src/bsp/lk/kernel/thread.c
new file mode 100644
index 0000000..688c1d4
--- /dev/null
+++ b/src/bsp/lk/kernel/thread.c
@@ -0,0 +1,1267 @@
+/*
+ * Copyright (c) 2008-2015 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * @file
+ * @brief  Kernel threading
+ *
+ * This file is the core kernel threading interface.
+ *
+ * @defgroup thread Threads
+ * @{
+ */
+#include <debug.h>
+#include <assert.h>
+#include <list.h>
+#include <malloc.h>
+#include <string.h>
+#include <printf.h>
+#include <err.h>
+#include <lib/dpc.h>
+#include <kernel/thread.h>
+#include <kernel/timer.h>
+#include <kernel/debug.h>
+#include <kernel/mp.h>
+#include <platform.h>
+#include <target.h>
+#include <lib/heap.h>
+
+#if THREAD_STATS
+struct thread_stats thread_stats[SMP_MAX_CPUS];
+#endif
+
+#define STACK_DEBUG_BYTE (0x99)
+#define STACK_DEBUG_WORD (0x99999999)
+
+#define DEBUG_THREAD_CONTEXT_SWITCH 0
+
+/* global thread list */
+static struct list_node thread_list;
+
+/* master thread spinlock */
+spin_lock_t thread_lock = SPIN_LOCK_INITIAL_VALUE;
+
+/* the run queue */
+static struct list_node run_queue[NUM_PRIORITIES];
+static uint32_t run_queue_bitmap;
+
+/* make sure the bitmap is large enough to cover our number of priorities */
+STATIC_ASSERT(NUM_PRIORITIES <= sizeof(run_queue_bitmap) * 8);
+
+/* the idle thread(s) (statically allocated) */
+#if WITH_SMP
+static thread_t _idle_threads[SMP_MAX_CPUS];
+#define idle_thread(cpu) (&_idle_threads[cpu])
+#else
+static thread_t _idle_thread;
+#define idle_thread(cpu) (&_idle_thread)
+#endif
+
+/* local routines */
+static void thread_resched(void);
+static void idle_thread_routine(void) __NO_RETURN;
+
+#if PLATFORM_HAS_DYNAMIC_TIMER
+/* preemption timer */
+static timer_t preempt_timer[SMP_MAX_CPUS];
+#endif
+
+/* run queue manipulation */
+static void insert_in_run_queue_head(thread_t *t)
+{
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(t->state == THREAD_READY);
+	DEBUG_ASSERT(!list_in_list(&t->queue_node));
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+
+	list_add_head(&run_queue[t->priority], &t->queue_node);
+	run_queue_bitmap |= (1<<t->priority);
+}
+
+static void insert_in_run_queue_tail(thread_t *t)
+{
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(t->state == THREAD_READY);
+	DEBUG_ASSERT(!list_in_list(&t->queue_node));
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+
+	list_add_tail(&run_queue[t->priority], &t->queue_node);
+	run_queue_bitmap |= (1<<t->priority);
+}
+
+static void init_thread_struct(thread_t *t, const char *name)
+{
+	memset(t, 0, sizeof(thread_t));
+	t->magic = THREAD_MAGIC;
+	thread_set_pinned_cpu(t, -1);
+	strlcpy(t->name, name, sizeof(t->name));
+}
+
+/**
+ * @brief  Create a new thread
+ *
+ * This function creates a new thread.  The thread is initially suspended, so you
+ * need to call thread_resume() to execute it.
+ *
+ * @param  name        Name of thread
+ * @param  entry       Entry point of thread
+ * @param  arg         Arbitrary argument passed to entry()
+ * @param  priority    Execution priority for the thread.
+ * @param  stack_size  Stack size for the thread.
+ *
+ * Thread priority is an integer from 0 (lowest) to 31 (highest).  Some standard
+ * prioritys are defined in <kernel/thread.h>:
+ *
+ *  HIGHEST_PRIORITY
+ *  DPC_PRIORITY
+ *  HIGH_PRIORITY
+ *  DEFAULT_PRIORITY
+ *  LOW_PRIORITY
+ *  IDLE_PRIORITY
+ *  LOWEST_PRIORITY
+ *
+ * Stack size is typically set to DEFAULT_STACK_SIZE
+ *
+ * @return  Pointer to thread object, or NULL on failure.
+ */
+thread_t *thread_create_etc(thread_t *t, const char *name, thread_start_routine entry, void *arg, int priority, void *stack, size_t stack_size)
+{
+	unsigned int flags = 0;
+
+	if (!t) {
+		t = malloc(sizeof(thread_t));
+		if (!t)
+			return NULL;
+		flags |= THREAD_FLAG_FREE_STRUCT;
+	}
+
+	init_thread_struct(t, name);
+
+	t->entry = entry;
+	t->arg = arg;
+	t->priority = priority;
+	t->state = THREAD_SUSPENDED;
+	t->blocking_wait_queue = NULL;
+	t->wait_queue_block_ret = NO_ERROR;
+	thread_set_curr_cpu(t, -1);
+
+	t->retcode = 0;
+	wait_queue_init(&t->retcode_wait_queue);
+
+	/* create the stack */
+	if (!stack) {
+#if THREAD_STACK_BOUNDS_CHECK
+		stack_size += THREAD_STACK_PADDING_SIZE;
+		flags |= THREAD_FLAG_DEBUG_STACK_BOUNDS_CHECK;
+#endif
+		t->stack = malloc(stack_size);
+		if (!t->stack) {
+			if (flags & THREAD_FLAG_FREE_STRUCT)
+				free(t);
+			return NULL;
+		}
+		flags |= THREAD_FLAG_FREE_STACK;
+#if THREAD_STACK_BOUNDS_CHECK
+		memset(t->stack, STACK_DEBUG_BYTE, THREAD_STACK_PADDING_SIZE);
+#endif
+	} else {
+		t->stack = stack;
+	}
+
+	t->stack_size = stack_size;
+
+	/* save whether or not we need to free the thread struct and/or stack */
+	t->flags = flags;
+
+	/* inheirit thread local storage from the parent */
+	thread_t *current_thread = get_current_thread();
+	int i;
+	for (i=0; i < MAX_TLS_ENTRY; i++)
+		t->tls[i] = current_thread->tls[i];
+
+	/* set up the initial stack frame */
+	arch_thread_initialize(t);
+
+	/* add it to the global thread list */
+	THREAD_LOCK(state);
+	list_add_head(&thread_list, &t->thread_list_node);
+	THREAD_UNLOCK(state);
+
+	return t;
+}
+
+thread_t *thread_create(const char *name, thread_start_routine entry, void *arg, int priority, size_t stack_size)
+{
+	return thread_create_etc(NULL, name, entry, arg, priority, NULL, stack_size);
+}
+
+/**
+ * @brief Flag a thread as real time
+ *
+ * @param t Thread to flag
+ *
+ * @return NO_ERROR on success
+ */
+status_t thread_set_real_time(thread_t *t)
+{
+	if (!t)
+		return ERR_INVALID_ARGS;
+
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+
+	THREAD_LOCK(state);
+#if PLATFORM_HAS_DYNAMIC_TIMER
+	if (t == get_current_thread()) {
+		/* if we're currently running, cancel the preemption timer. */
+		timer_cancel(&preempt_timer[arch_curr_cpu_num()]);
+	}
+#endif
+	t->flags |= THREAD_FLAG_REAL_TIME;
+	THREAD_UNLOCK(state);
+
+	return NO_ERROR;
+}
+
+static bool thread_is_realtime(thread_t *t)
+{
+	return (t->flags & THREAD_FLAG_REAL_TIME) && t->priority > DEFAULT_PRIORITY;
+}
+
+static bool thread_is_idle(thread_t *t)
+{
+	return !!(t->flags & THREAD_FLAG_IDLE);
+}
+
+static bool thread_is_real_time_or_idle(thread_t *t)
+{
+	return !!(t->flags & (THREAD_FLAG_REAL_TIME | THREAD_FLAG_IDLE));
+}
+
+/**
+ * @brief  Make a suspended thread executable.
+ *
+ * This function is typically called to start a thread which has just been
+ * created with thread_create()
+ *
+ * @param t  Thread to resume
+ *
+ * @return NO_ERROR on success, ERR_NOT_SUSPENDED if thread was not suspended.
+ */
+status_t thread_resume(thread_t *t)
+{
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(t->state != THREAD_DEATH);
+
+	bool resched = false;
+	bool ints_disabled = arch_ints_disabled();
+	THREAD_LOCK(state);
+	if (t->state == THREAD_SUSPENDED) {
+		t->state = THREAD_READY;
+		insert_in_run_queue_head(t);
+		if (!ints_disabled) /* HACK, don't resced into bootstrap thread before idle thread is set up */
+			resched = true;
+	}
+
+	mp_reschedule(MP_CPU_ALL_BUT_LOCAL, 0);
+
+	THREAD_UNLOCK(state);
+
+	if (resched)
+		thread_yield();
+
+	return NO_ERROR;
+}
+
+status_t thread_detach_and_resume(thread_t *t)
+{
+	status_t err;
+	err = thread_detach(t);
+	if (err < 0)
+		return err;
+	return thread_resume(t);
+}
+
+status_t thread_join(thread_t *t, int *retcode, lk_time_t timeout)
+{
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+
+	THREAD_LOCK(state);
+
+	if (t->flags & THREAD_FLAG_DETACHED) {
+		/* the thread is detached, go ahead and exit */
+		THREAD_UNLOCK(state);
+		return ERR_THREAD_DETACHED;
+	}
+
+	/* wait for the thread to die */
+	if (t->state != THREAD_DEATH) {
+		status_t err = wait_queue_block(&t->retcode_wait_queue, timeout);
+		if (err < 0) {
+			THREAD_UNLOCK(state);
+			return err;
+		}
+	}
+
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(t->state == THREAD_DEATH);
+	DEBUG_ASSERT(t->blocking_wait_queue == NULL);
+	DEBUG_ASSERT(!list_in_list(&t->queue_node));
+
+	/* save the return code */
+	if (retcode)
+		*retcode = t->retcode;
+
+	/* remove it from the master thread list */
+	list_delete(&t->thread_list_node);
+
+	/* clear the structure's magic */
+	t->magic = 0;
+
+	THREAD_UNLOCK(state);
+
+	/* free its stack and the thread structure itself */
+	if (t->flags & THREAD_FLAG_FREE_STACK && t->stack)
+		free(t->stack);
+
+	if (t->flags & THREAD_FLAG_FREE_STRUCT)
+		free(t);
+
+	return NO_ERROR;
+}
+
+status_t thread_detach(thread_t *t)
+{
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+
+	THREAD_LOCK(state);
+
+	/* if another thread is blocked inside thread_join() on this thread,
+	 * wake them up with a specific return code */
+	wait_queue_wake_all(&t->retcode_wait_queue, false, ERR_THREAD_DETACHED);
+
+	/* if it's already dead, then just do what join would have and exit */
+	if (t->state == THREAD_DEATH) {
+		t->flags &= ~THREAD_FLAG_DETACHED; /* makes sure thread_join continues */
+		THREAD_UNLOCK(state);
+		return thread_join(t, NULL, 0);
+	} else {
+		t->flags |= THREAD_FLAG_DETACHED;
+		THREAD_UNLOCK(state);
+		return NO_ERROR;
+	}
+}
+
+/**
+ * @brief  Terminate the current thread
+ *
+ * Current thread exits with the specified return code.
+ *
+ * This function does not return.
+ */
+void thread_exit(int retcode)
+{
+	thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(current_thread->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(current_thread->state == THREAD_RUNNING);
+	DEBUG_ASSERT(!thread_is_idle(current_thread));
+
+//	dprintf("thread_exit: current %p\n", current_thread);
+
+	THREAD_LOCK(state);
+
+	/* enter the dead state */
+	current_thread->state = THREAD_DEATH;
+	current_thread->retcode = retcode;
+
+	/* if we're detached, then do our teardown here */
+	if (current_thread->flags & THREAD_FLAG_DETACHED) {
+		/* remove it from the master thread list */
+		list_delete(&current_thread->thread_list_node);
+
+		/* clear the structure's magic */
+		current_thread->magic = 0;
+
+		/* free its stack and the thread structure itself */
+		if (current_thread->flags & THREAD_FLAG_FREE_STACK && current_thread->stack) {
+			heap_delayed_free(current_thread->stack);
+
+			/* make sure its not going to get a bounds check performed on the half-freed stack */
+			current_thread->flags &= ~THREAD_FLAG_DEBUG_STACK_BOUNDS_CHECK;
+		}
+
+		if (current_thread->flags & THREAD_FLAG_FREE_STRUCT)
+			heap_delayed_free(current_thread);
+	} else {
+		/* signal if anyone is waiting */
+		wait_queue_wake_all(&current_thread->retcode_wait_queue, false, 0);
+	}
+
+	/* reschedule */
+	thread_resched();
+
+	panic("somehow fell through thread_exit()\n");
+}
+
+static void idle_thread_routine(void)
+{
+	for (;;)
+		arch_idle();
+}
+
+static thread_t *get_top_thread(int cpu)
+{
+	thread_t *newthread;
+	uint32_t local_run_queue_bitmap = run_queue_bitmap;
+
+	while (local_run_queue_bitmap) {
+		/* find the first (remaining) queue with a thread in it */
+		uint next_queue = HIGHEST_PRIORITY - __builtin_clz(local_run_queue_bitmap)
+			- (sizeof(run_queue_bitmap) * 8 - NUM_PRIORITIES);
+
+		list_for_every_entry(&run_queue[next_queue], newthread, thread_t, queue_node) {
+#if WITH_SMP
+			if (newthread->pinned_cpu < 0 || newthread->pinned_cpu == cpu)
+#endif
+			{
+				list_delete(&newthread->queue_node);
+
+				if (list_is_empty(&run_queue[next_queue]))
+					run_queue_bitmap &= ~(1<<next_queue);
+
+				return newthread;
+			}
+		}
+
+		local_run_queue_bitmap &= ~(1<<next_queue);
+	}
+	/* no threads to run, select the idle thread for this cpu */
+	return idle_thread(cpu);
+}
+
+/**
+ * @brief  Cause another thread to be executed.
+ *
+ * Internal reschedule routine. The current thread needs to already be in whatever
+ * state and queues it needs to be in. This routine simply picks the next thread and
+ * switches to it.
+ *
+ * This is probably not the function you're looking for. See
+ * thread_yield() instead.
+ */
+void thread_resched(void)
+{
+	thread_t *oldthread;
+	thread_t *newthread;
+
+	thread_t *current_thread = get_current_thread();
+	uint cpu = arch_curr_cpu_num();
+
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+	DEBUG_ASSERT(current_thread->state != THREAD_RUNNING);
+
+	THREAD_STATS_INC(reschedules);
+
+	newthread = get_top_thread(cpu);
+
+	DEBUG_ASSERT(newthread);
+
+	newthread->state = THREAD_RUNNING;
+
+	oldthread = current_thread;
+
+	if (newthread == oldthread)
+		return;
+
+	/* set up quantum for the new thread if it was consumed */
+	if (newthread->remaining_quantum <= 0) {
+		newthread->remaining_quantum = 5; // XXX make this smarter
+	}
+
+	/* mark the cpu ownership of the threads */
+	thread_set_curr_cpu(oldthread, -1);
+	thread_set_curr_cpu(newthread, cpu);
+
+#if WITH_SMP
+	if (thread_is_idle(newthread)) {
+		mp_set_cpu_idle(cpu);
+	} else {
+		mp_set_cpu_busy(cpu);
+	}
+
+	if (thread_is_realtime(newthread)) {
+		mp_set_cpu_realtime(cpu);
+	} else {
+		mp_set_cpu_non_realtime(cpu);
+	}
+#endif
+
+#if THREAD_STATS
+	THREAD_STATS_INC(context_switches);
+
+	if (thread_is_idle(oldthread)) {
+		lk_bigtime_t now = current_time_hires();
+		thread_stats[cpu].idle_time += now - thread_stats[cpu].last_idle_timestamp;
+	}
+	if (thread_is_idle(newthread)) {
+		thread_stats[cpu].last_idle_timestamp = current_time_hires();
+	}
+#endif
+
+	KEVLOG_THREAD_SWITCH(oldthread, newthread);
+
+#if PLATFORM_HAS_DYNAMIC_TIMER
+	if (thread_is_real_time_or_idle(newthread)) {
+		if (!thread_is_real_time_or_idle(oldthread)) {
+			/* if we're switching from a non real time to a real time, cancel
+			 * the preemption timer. */
+#if DEBUG_THREAD_CONTEXT_SWITCH
+			dprintf(ALWAYS, "arch_context_switch: stop preempt, cpu %d, old %p (%s), new %p (%s)\n",
+				cpu, oldthread, oldthread->name, newthread, newthread->name);
+#endif
+			timer_cancel(&preempt_timer[cpu]);
+		}
+	} else if (thread_is_real_time_or_idle(oldthread)) {
+		/* if we're switching from a real time (or idle thread) to a regular one,
+		 * set up a periodic timer to run our preemption tick. */
+#if DEBUG_THREAD_CONTEXT_SWITCH
+		dprintf(ALWAYS, "arch_context_switch: start preempt, cpu %d, old %p (%s), new %p (%s)\n",
+			cpu, oldthread, oldthread->name, newthread, newthread->name);
+#endif
+		timer_set_periodic(&preempt_timer[cpu], 10, thread_timer_tick, NULL);
+	}
+#endif
+
+	/* set some optional target debug leds */
+	target_set_debug_led(0, !thread_is_idle(newthread));
+
+	/* do the switch */
+	set_current_thread(newthread);
+
+#if DEBUG_THREAD_CONTEXT_SWITCH
+	dprintf(ALWAYS, "arch_context_switch: cpu %d, old %p (%s, pri %d, flags 0x%x), new %p (%s, pri %d, flags 0x%x)\n",
+		cpu, oldthread, oldthread->name, oldthread->priority,
+		oldthread->flags, newthread, newthread->name,
+		newthread->priority, newthread->flags);
+#endif
+
+#if THREAD_STACK_BOUNDS_CHECK
+	/* check that the old thread has not blown its stack just before pushing its context */
+	if (oldthread->flags & THREAD_FLAG_DEBUG_STACK_BOUNDS_CHECK) {
+		STATIC_ASSERT((THREAD_STACK_PADDING_SIZE % sizeof(uint32_t)) == 0);
+		uint32_t *s = (uint32_t *)oldthread->stack;
+		for (size_t i = 0; i < THREAD_STACK_PADDING_SIZE / sizeof(uint32_t); i++) {
+			if (unlikely(s[i] != STACK_DEBUG_WORD)) {
+				/* NOTE: will probably blow the stack harder here, but hopefully enough
+				 * state exists to at least get some sort of debugging done.
+				 */
+				panic("stack overrun at %p: thread %p (%s), stack %p\n", &s[i],
+						oldthread, oldthread->name, oldthread->stack);
+			}
+		}
+	}
+#endif
+
+#ifdef WITH_LIB_UTHREAD
+	uthread_context_switch(oldthread, newthread);
+#endif
+	arch_context_switch(oldthread, newthread);
+}
+
+/**
+ * @brief Yield the cpu to another thread
+ *
+ * This function places the current thread at the end of the run queue
+ * and yields the cpu to another waiting thread (if any.)
+ *
+ * This function will return at some later time. Possibly immediately if
+ * no other threads are waiting to execute.
+ */
+void thread_yield(void)
+{
+	thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(current_thread->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(current_thread->state == THREAD_RUNNING);
+
+	THREAD_LOCK(state);
+
+	THREAD_STATS_INC(yields);
+
+	/* we are yielding the cpu, so stick ourselves into the tail of the run queue and reschedule */
+	current_thread->state = THREAD_READY;
+	current_thread->remaining_quantum = 0;
+	if (likely(!thread_is_idle(current_thread))) { /* idle thread doesn't go in the run queue */
+		insert_in_run_queue_tail(current_thread);
+	}
+	thread_resched();
+
+	THREAD_UNLOCK(state);
+}
+
+/**
+ * @brief  Briefly yield cpu to another thread
+ *
+ * This function is similar to thread_yield(), except that it will
+ * restart more quickly.
+ *
+ * This function places the current thread at the head of the run
+ * queue and then yields the cpu to another thread.
+ *
+ * Exception:  If the time slice for this thread has expired, then
+ * the thread goes to the end of the run queue.
+ *
+ * This function will return at some later time. Possibly immediately if
+ * no other threads are waiting to execute.
+ */
+void thread_preempt(void)
+{
+	thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(current_thread->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(current_thread->state == THREAD_RUNNING);
+
+#if THREAD_STATS
+	if (!thread_is_idle(current_thread))
+		THREAD_STATS_INC(preempts); /* only track when a meaningful preempt happens */
+#endif
+
+	KEVLOG_THREAD_PREEMPT(current_thread);
+
+	THREAD_LOCK(state);
+
+	/* we are being preempted, so we get to go back into the front of the run queue if we have quantum left */
+	current_thread->state = THREAD_READY;
+	if (likely(!thread_is_idle(current_thread))) { /* idle thread doesn't go in the run queue */
+		if (current_thread->remaining_quantum > 0)
+			insert_in_run_queue_head(current_thread);
+		else
+			insert_in_run_queue_tail(current_thread); /* if we're out of quantum, go to the tail of the queue */
+	}
+	thread_resched();
+
+	THREAD_UNLOCK(state);
+}
+
+/**
+ * @brief  Suspend thread until woken.
+ *
+ * This function schedules another thread to execute.  This function does not
+ * return until the thread is made runable again by some other module.
+ *
+ * You probably don't want to call this function directly; it's meant to be called
+ * from other modules, such as mutex, which will presumably set the thread's
+ * state to blocked and add it to some queue or another.
+ */
+void thread_block(void)
+{
+	__UNUSED thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(current_thread->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(current_thread->state == THREAD_BLOCKED);
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+	DEBUG_ASSERT(!thread_is_idle(current_thread));
+
+	/* we are blocking on something. the blocking code should have already stuck us on a queue */
+	thread_resched();
+}
+
+void thread_unblock(thread_t *t, bool resched)
+{
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(t->state == THREAD_BLOCKED);
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+	DEBUG_ASSERT(!thread_is_idle(t));
+
+	t->state = THREAD_READY;
+	insert_in_run_queue_head(t);
+	mp_reschedule(MP_CPU_ALL_BUT_LOCAL, 0);
+	if (resched)
+		thread_resched();
+}
+
+enum handler_return thread_timer_tick(struct timer *t, lk_time_t now, void *arg)
+{
+	thread_t *current_thread = get_current_thread();
+
+	if (thread_is_real_time_or_idle(current_thread))
+		return INT_NO_RESCHEDULE;
+
+	current_thread->remaining_quantum--;
+	if (current_thread->remaining_quantum <= 0) {
+		return INT_RESCHEDULE;
+	} else {
+		return INT_NO_RESCHEDULE;
+	}
+}
+
+/* timer callback to wake up a sleeping thread */
+static enum handler_return thread_sleep_handler(timer_t *timer, lk_time_t now, void *arg)
+{
+	thread_t *t = (thread_t *)arg;
+
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(t->state == THREAD_SLEEPING);
+
+	THREAD_LOCK(state);
+
+	t->state = THREAD_READY;
+	insert_in_run_queue_head(t);
+
+	THREAD_UNLOCK(state);
+
+	return INT_RESCHEDULE;
+}
+
+/**
+ * @brief  Put thread to sleep; delay specified in ms
+ *
+ * This function puts the current thread to sleep until the specified
+ * delay in ms has expired.
+ *
+ * Note that this function could sleep for longer than the specified delay if
+ * other threads are running.  When the timer expires, this thread will
+ * be placed at the head of the run queue.
+ */
+void thread_sleep(lk_time_t delay)
+{
+	timer_t timer;
+
+	thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(current_thread->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(current_thread->state == THREAD_RUNNING);
+	DEBUG_ASSERT(!thread_is_idle(current_thread));
+
+	timer_initialize(&timer);
+
+	THREAD_LOCK(state);
+	timer_set_oneshot(&timer, delay, thread_sleep_handler, (void *)current_thread);
+	current_thread->state = THREAD_SLEEPING;
+	thread_resched();
+	THREAD_UNLOCK(state);
+}
+
+/**
+ * @brief  Initialize threading system
+ *
+ * This function is called once, from kmain()
+ */
+void thread_init_early(void)
+{
+	int i;
+
+	DEBUG_ASSERT(arch_curr_cpu_num() == 0);
+
+	/* initialize the run queues */
+	for (i=0; i < NUM_PRIORITIES; i++)
+		list_initialize(&run_queue[i]);
+
+	/* initialize the thread list */
+	list_initialize(&thread_list);
+
+	/* create a thread to cover the current running state */
+	thread_t *t = idle_thread(0);
+	init_thread_struct(t, "bootstrap");
+
+	/* half construct this thread, since we're already running */
+	t->priority = HIGHEST_PRIORITY;
+	t->state = THREAD_RUNNING;
+	t->flags = THREAD_FLAG_DETACHED;
+	thread_set_curr_cpu(t, 0);
+	thread_set_pinned_cpu(t, 0);
+	wait_queue_init(&t->retcode_wait_queue);
+	list_add_head(&thread_list, &t->thread_list_node);
+	set_current_thread(t);
+}
+
+/**
+ * @brief Complete thread initialization
+ *
+ * This function is called once at boot time
+ */
+void thread_init(void)
+{
+#if PLATFORM_HAS_DYNAMIC_TIMER
+	for (uint i = 0; i < SMP_MAX_CPUS; i++) {
+		timer_initialize(&preempt_timer[i]);
+	}
+#endif
+}
+
+/**
+ * @brief Change name of current thread
+ */
+void thread_set_name(const char *name)
+{
+	thread_t *current_thread = get_current_thread();
+	strlcpy(current_thread->name, name, sizeof(current_thread->name));
+}
+
+/**
+ * @brief Change priority of current thread
+ *
+ * See thread_create() for a discussion of priority values.
+ */
+void thread_set_priority(int priority)
+{
+	thread_t *current_thread = get_current_thread();
+
+	THREAD_LOCK(state);
+
+	if (priority <= IDLE_PRIORITY)
+		priority = IDLE_PRIORITY + 1;
+	if (priority > HIGHEST_PRIORITY)
+		priority = HIGHEST_PRIORITY;
+	current_thread->priority = priority;
+
+	current_thread->state = THREAD_READY;
+	insert_in_run_queue_head(current_thread);
+	thread_resched();
+
+	THREAD_UNLOCK(state);
+}
+
+/**
+ * @brief  Become an idle thread
+ *
+ * This function marks the current thread as the idle thread -- the one which
+ * executes when there is nothing else to do.  This function does not return.
+ * This function is called once at boot time.
+ */
+void thread_become_idle(void)
+{
+	DEBUG_ASSERT(arch_ints_disabled());
+
+	thread_t *t = get_current_thread();
+
+#if WITH_SMP
+	char name[16];
+	snprintf(name, sizeof(name), "idle %d", arch_curr_cpu_num());
+	thread_set_name(name);
+#else
+	thread_set_name("idle");
+#endif
+
+	/* mark ourself as idle */
+	t->priority = IDLE_PRIORITY;
+	t->flags |= THREAD_FLAG_IDLE;
+	thread_set_pinned_cpu(t, arch_curr_cpu_num());
+
+	mp_set_curr_cpu_active(true);
+	mp_set_cpu_idle(arch_curr_cpu_num());
+
+	/* enable interrupts and start the scheduler */
+	arch_enable_ints();
+	thread_yield();
+
+	idle_thread_routine();
+}
+
+/* create an idle thread for the cpu we're on, and start scheduling */
+
+void thread_secondary_cpu_init_early(void)
+{
+	DEBUG_ASSERT(arch_ints_disabled());
+
+	/* construct an idle thread to cover our cpu */
+	uint cpu = arch_curr_cpu_num();
+	thread_t *t = idle_thread(cpu);
+
+	char name[16];
+	snprintf(name, sizeof(name), "idle %u", cpu);
+	init_thread_struct(t, name);
+	thread_set_pinned_cpu(t, cpu);
+
+	/* half construct this thread, since we're already running */
+	t->priority = HIGHEST_PRIORITY;
+	t->state = THREAD_RUNNING;
+	t->flags = THREAD_FLAG_DETACHED | THREAD_FLAG_IDLE;
+	thread_set_curr_cpu(t, cpu);
+	thread_set_pinned_cpu(t, cpu);
+	wait_queue_init(&t->retcode_wait_queue);
+
+	THREAD_LOCK(state);
+
+	list_add_head(&thread_list, &t->thread_list_node);
+	set_current_thread(t);
+
+	THREAD_UNLOCK(state);
+}
+
+void thread_secondary_cpu_entry(void)
+{
+	uint cpu = arch_curr_cpu_num();
+	thread_t *t = get_current_thread();
+	t->priority = IDLE_PRIORITY;
+
+	mp_set_curr_cpu_active(true);
+	mp_set_cpu_idle(cpu);
+
+	/* enable interrupts and start the scheduler on this cpu */
+	arch_enable_ints();
+	thread_yield();
+
+	idle_thread_routine();
+}
+
+static const char *thread_state_to_str(enum thread_state state)
+{
+	switch (state) {
+		case THREAD_SUSPENDED: return "susp";
+		case THREAD_READY: return "rdy";
+		case THREAD_RUNNING: return "run";
+		case THREAD_BLOCKED: return "blok";
+		case THREAD_SLEEPING: return "slep";
+		case THREAD_DEATH: return "deth";
+		default: return "unkn";
+	}
+}
+
+/**
+ * @brief  Dump debugging info about the specified thread.
+ */
+void dump_thread(thread_t *t)
+{
+	dprintf(INFO, "dump_thread: t %p (%s)\n", t, t->name);
+#if WITH_SMP
+	dprintf(INFO, "\tstate %s, curr_cpu %d, pinned_cpu %d, priority %d, remaining quantum %d\n",
+				  thread_state_to_str(t->state), t->curr_cpu, t->pinned_cpu, t->priority, t->remaining_quantum);
+#else
+	dprintf(INFO, "\tstate %s, priority %d, remaining quantum %d\n",
+				  thread_state_to_str(t->state), t->priority, t->remaining_quantum);
+#endif
+	dprintf(INFO, "\tstack %p, stack_size %zd\n", t->stack, t->stack_size);
+	dprintf(INFO, "\tentry %p, arg %p, flags 0x%x\n", t->entry, t->arg, t->flags);
+	dprintf(INFO, "\twait queue %p, wait queue ret %d\n", t->blocking_wait_queue, t->wait_queue_block_ret);
+#if (MAX_TLS_ENTRY > 0)
+	dprintf(INFO, "\ttls:");
+	int i;
+	for (i=0; i < MAX_TLS_ENTRY; i++) {
+		dprintf(INFO, " 0x%lx", t->tls[i]);
+	}
+	dprintf(INFO, "\n");
+#endif
+	arch_dump_thread(t);
+}
+
+/**
+ * @brief  Dump debugging info about all threads
+ */
+void dump_all_threads(void)
+{
+	thread_t *t;
+
+	THREAD_LOCK(state);
+	list_for_every_entry(&thread_list, t, thread_t, thread_list_node) {
+		if (t->magic != THREAD_MAGIC) {
+			dprintf(INFO, "bad magic on thread struct %p, aborting.\n", t);
+			hexdump(t, sizeof(thread_t));
+			break;
+		}
+		dump_thread(t);
+	}
+	THREAD_UNLOCK(state);
+}
+
+/** @} */
+
+
+/**
+ * @defgroup  wait  Wait Queue
+ * @{
+ */
+void wait_queue_init(wait_queue_t *wait)
+{
+	*wait = (wait_queue_t)WAIT_QUEUE_INITIAL_VALUE(*wait);
+}
+
+static enum handler_return wait_queue_timeout_handler(timer_t *timer, lk_time_t now, void *arg)
+{
+	thread_t *thread = (thread_t *)arg;
+
+	DEBUG_ASSERT(thread->magic == THREAD_MAGIC);
+
+	spin_lock(&thread_lock);
+
+	enum handler_return ret = INT_NO_RESCHEDULE;
+	if (thread_unblock_from_wait_queue(thread, ERR_TIMED_OUT) >= NO_ERROR) {
+		ret = INT_RESCHEDULE;
+	}
+
+	spin_unlock(&thread_lock);
+
+	return ret;
+}
+
+/**
+ * @brief  Block until a wait queue is notified.
+ *
+ * This function puts the current thread at the end of a wait
+ * queue and then blocks until some other thread wakes the queue
+ * up again.
+ *
+ * @param  wait     The wait queue to enter
+ * @param  timeout  The maximum time, in ms, to wait
+ *
+ * If the timeout is zero, this function returns immediately with
+ * ERR_TIMED_OUT.  If the timeout is INFINITE_TIME, this function
+ * waits indefinitely.  Otherwise, this function returns with
+ * ERR_TIMED_OUT at the end of the timeout period.
+ *
+ * @return ERR_TIMED_OUT on timeout, else returns the return
+ * value specified when the queue was woken by wait_queue_wake_one().
+ */
+status_t wait_queue_block(wait_queue_t *wait, lk_time_t timeout)
+{
+	timer_t timer;
+
+	thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(wait->magic == WAIT_QUEUE_MAGIC);
+	DEBUG_ASSERT(current_thread->state == THREAD_RUNNING);
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+
+	if (timeout == 0)
+		return ERR_TIMED_OUT;
+
+	list_add_tail(&wait->list, &current_thread->queue_node);
+	wait->count++;
+	current_thread->state = THREAD_BLOCKED;
+	current_thread->blocking_wait_queue = wait;
+	current_thread->wait_queue_block_ret = NO_ERROR;
+
+	/* if the timeout is nonzero or noninfinite, set a callback to yank us out of the queue */
+	if (timeout != INFINITE_TIME) {
+		timer_initialize(&timer);
+		timer_set_oneshot(&timer, timeout, wait_queue_timeout_handler, (void *)current_thread);
+	}
+
+	thread_resched();
+
+	/* we don't really know if the timer fired or not, so it's better safe to try to cancel it */
+	if (timeout != INFINITE_TIME) {
+		timer_cancel(&timer);
+	}
+
+	return current_thread->wait_queue_block_ret;
+}
+
+/**
+ * @brief  Wake up one thread sleeping on a wait queue
+ *
+ * This function removes one thread (if any) from the head of the wait queue and
+ * makes it executable.  The new thread will be placed at the head of the
+ * run queue.
+ *
+ * @param wait  The wait queue to wake
+ * @param reschedule  If true, the newly-woken thread will run immediately.
+ * @param wait_queue_error  The return value which the new thread will receive
+ * from wait_queue_block().
+ *
+ * @return  The number of threads woken (zero or one)
+ */
+int wait_queue_wake_one(wait_queue_t *wait, bool reschedule, status_t wait_queue_error)
+{
+	thread_t *t;
+	int ret = 0;
+
+	thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(wait->magic == WAIT_QUEUE_MAGIC);
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+
+	t = list_remove_head_type(&wait->list, thread_t, queue_node);
+	if (t) {
+		wait->count--;
+		DEBUG_ASSERT(t->state == THREAD_BLOCKED);
+		t->state = THREAD_READY;
+		t->wait_queue_block_ret = wait_queue_error;
+		t->blocking_wait_queue = NULL;
+
+		/* if we're instructed to reschedule, stick the current thread on the head
+		 * of the run queue first, so that the newly awakened thread gets a chance to run
+		 * before the current one, but the current one doesn't get unnecessarilly punished.
+		 */
+		if (reschedule) {
+			current_thread->state = THREAD_READY;
+			insert_in_run_queue_head(current_thread);
+		}
+		insert_in_run_queue_head(t);
+		mp_reschedule(MP_CPU_ALL_BUT_LOCAL, 0);
+		if (reschedule) {
+			thread_resched();
+		}
+		ret = 1;
+
+	}
+
+	return ret;
+}
+
+
+/**
+ * @brief  Wake all threads sleeping on a wait queue
+ *
+ * This function removes all threads (if any) from the wait queue and
+ * makes them executable.  The new threads will be placed at the head of the
+ * run queue.
+ *
+ * @param wait  The wait queue to wake
+ * @param reschedule  If true, the newly-woken threads will run immediately.
+ * @param wait_queue_error  The return value which the new thread will receive
+ * from wait_queue_block().
+ *
+ * @return  The number of threads woken (zero or one)
+ */
+int wait_queue_wake_all(wait_queue_t *wait, bool reschedule, status_t wait_queue_error)
+{
+	thread_t *t;
+	int ret = 0;
+
+	thread_t *current_thread = get_current_thread();
+
+	DEBUG_ASSERT(wait->magic == WAIT_QUEUE_MAGIC);
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+
+	if (reschedule && wait->count > 0) {
+		/* if we're instructed to reschedule, stick the current thread on the head
+		 * of the run queue first, so that the newly awakened threads get a chance to run
+		 * before the current one, but the current one doesn't get unnecessarilly punished.
+		 */
+		current_thread->state = THREAD_READY;
+		insert_in_run_queue_head(current_thread);
+	}
+
+	/* pop all the threads off the wait queue into the run queue */
+	while ((t = list_remove_head_type(&wait->list, thread_t, queue_node))) {
+		wait->count--;
+		DEBUG_ASSERT(t->state == THREAD_BLOCKED);
+		t->state = THREAD_READY;
+		t->wait_queue_block_ret = wait_queue_error;
+		t->blocking_wait_queue = NULL;
+
+		insert_in_run_queue_head(t);
+		ret++;
+	}
+
+	DEBUG_ASSERT(wait->count == 0);
+
+	if (ret > 0) {
+		mp_reschedule(MP_CPU_ALL_BUT_LOCAL, 0);
+		if (reschedule) {
+			thread_resched();
+		}
+	}
+
+	return ret;
+}
+
+/**
+ * @brief  Free all resources allocated in wait_queue_init()
+ *
+ * If any threads were waiting on this queue, they are all woken.
+ */
+void wait_queue_destroy(wait_queue_t *wait, bool reschedule)
+{
+	DEBUG_ASSERT(wait->magic == WAIT_QUEUE_MAGIC);
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+
+	wait_queue_wake_all(wait, reschedule, ERR_OBJECT_DESTROYED);
+	wait->magic = 0;
+}
+
+/**
+ * @brief  Wake a specific thread in a wait queue
+ *
+ * This function extracts a specific thread from a wait queue, wakes it, and
+ * puts it at the head of the run queue.
+ *
+ * @param t  The thread to wake
+ * @param wait_queue_error  The return value which the new thread will receive
+ *   from wait_queue_block().
+ *
+ * @return ERR_NOT_BLOCKED if thread was not in any wait queue.
+ */
+status_t thread_unblock_from_wait_queue(thread_t *t, status_t wait_queue_error)
+{
+	DEBUG_ASSERT(t->magic == THREAD_MAGIC);
+	DEBUG_ASSERT(arch_ints_disabled());
+	DEBUG_ASSERT(spin_lock_held(&thread_lock));
+
+	if (t->state != THREAD_BLOCKED)
+		return ERR_NOT_BLOCKED;
+
+	DEBUG_ASSERT(t->blocking_wait_queue != NULL);
+	DEBUG_ASSERT(t->blocking_wait_queue->magic == WAIT_QUEUE_MAGIC);
+	DEBUG_ASSERT(list_in_list(&t->queue_node));
+
+	list_delete(&t->queue_node);
+	t->blocking_wait_queue->count--;
+	t->blocking_wait_queue = NULL;
+	t->state = THREAD_READY;
+	t->wait_queue_block_ret = wait_queue_error;
+	insert_in_run_queue_head(t);
+	mp_reschedule(MP_CPU_ALL_BUT_LOCAL, 0);
+
+	return NO_ERROR;
+}
+
+#if defined(WITH_DEBUGGER_INFO)
+// This is, by necessity, arch-specific, and arm-m specific right now,
+// but lives here due to thread_list being static.
+//
+// It contains sufficient information for a remote debugger to walk
+// the thread list without needing the symbols and debug sections in
+// the elf binary for lk or the ability to parse them.
+const struct __debugger_info__ {
+	u32 version; // flags:16 major:8 minor:8
+	void *thread_list_ptr;
+	void *current_thread_ptr;
+	u8 off_list_node;
+	u8 off_state;
+	u8 off_saved_sp;
+	u8 off_was_preempted;
+	u8 off_name;
+	u8 off_waitq;
+} _debugger_info = {
+	.version = 0x0100,
+	.thread_list_ptr = &thread_list,
+	.current_thread_ptr = &_current_thread,
+	.off_list_node = __builtin_offsetof(thread_t, thread_list_node),
+	.off_state = __builtin_offsetof(thread_t, state),
+	.off_saved_sp = __builtin_offsetof(thread_t, arch.sp),
+	.off_was_preempted = __builtin_offsetof(thread_t, arch.was_preempted),
+	.off_name = __builtin_offsetof(thread_t, name),
+	.off_waitq = __builtin_offsetof(thread_t, blocking_wait_queue),
+};
+#endif
+
+/* vim: set ts=4 sw=4 noexpandtab: */