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/*

 * Copyright (C) 2001-2004 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup genericproc

 * @{

 */

/**

 * @file

 * @brief	Thread management functions.

 */

#include <proc/scheduler.h>

#include <proc/thread.h>

#include <proc/task.h>

#include <proc/uarg.h>

#include <mm/frame.h>

#include <mm/page.h>

#include <arch/asm.h>

#include <arch.h>

#include <synch/synch.h>

#include <synch/spinlock.h>

#include <synch/waitq.h>

#include <synch/rwlock.h>

#include <cpu.h>

#include <func.h>

#include <context.h>

#include <adt/btree.h>

#include <adt/list.h>

#include <typedefs.h>

#include <time/clock.h>

#include <config.h>

#include <arch/interrupt.h>

#include <smp/ipi.h>

#include <arch/faddr.h>

#include <atomic.h>

#include <memstr.h>

#include <print.h>

#include <mm/slab.h>

#include <debug.h>

#include <main/uinit.h>

#include <syscall/copy.h>

#include <errno.h>

/** Thread states */

char *thread_states[] = {

	"Invalid",

	"Running",

	"Sleeping",

	"Ready",

	"Entering",

	"Exiting",

	"Undead"

}; 

/** Lock protecting the threads_btree B+tree. For locking rules, see declaration thereof. */

SPINLOCK_INITIALIZE(threads_lock);

/** B+tree of all threads.

 *

 * When a thread is found in the threads_btree B+tree, it is guaranteed to exist as long

 * as the threads_lock is held.

 */

btree_t threads_btree;		

SPINLOCK_INITIALIZE(tidlock);

uint32_t last_tid = 0;

static slab_cache_t *thread_slab;

#ifdef ARCH_HAS_FPU

slab_cache_t *fpu_context_slab;

#endif

/** Thread wrapper

 *

 * This wrapper is provided to ensure that every thread

 * makes a call to thread_exit() when its implementing

 * function returns.

 *

 * interrupts_disable() is assumed.

 *

 */

static void cushion(void)

{

	void (*f)(void *) = THREAD->thread_code;

	void *arg = THREAD->thread_arg;

	/* this is where each thread wakes up after its creation */

	spinlock_unlock(&THREAD->lock);

	interrupts_enable();

	f(arg);

	thread_exit();

	/* not reached */

}

/** Initialization and allocation for thread_t structure */

static int thr_constructor(void *obj, int kmflags)

{

	thread_t *t = (thread_t *)obj;

	spinlock_initialize(&t->lock, "thread_t_lock");

	link_initialize(&t->rq_link);

	link_initialize(&t->wq_link);

	link_initialize(&t->th_link);

#ifdef ARCH_HAS_FPU

#  ifdef CONFIG_FPU_LAZY

	t->saved_fpu_context = NULL;

#  else

	t->saved_fpu_context = slab_alloc(fpu_context_slab,kmflags);

	if (!t->saved_fpu_context)

		return -1;

#  endif

#endif	

	t->kstack = frame_alloc(STACK_FRAMES, FRAME_KA | kmflags);

	if (! t->kstack) {

#ifdef ARCH_HAS_FPU

		if (t->saved_fpu_context)

			slab_free(fpu_context_slab,t->saved_fpu_context);

#endif

		return -1;

	}

	return 0;

}

/** Destruction of thread_t object */

static int thr_destructor(void *obj)

{

	thread_t *t = (thread_t *)obj;

	frame_free(KA2PA(t->kstack));

#ifdef ARCH_HAS_FPU

	if (t->saved_fpu_context)

		slab_free(fpu_context_slab,t->saved_fpu_context);

#endif

	return 1; /* One page freed */

}

/** Initialize threads

 *

 * Initialize kernel threads support.

 *

 */

void thread_init(void)

{

	THREAD = NULL;

	atomic_set(&nrdy,0);

	thread_slab = slab_cache_create("thread_slab", 

					sizeof(thread_t),0, 

					thr_constructor, thr_destructor, 0);

#ifdef ARCH_HAS_FPU

	fpu_context_slab = slab_cache_create("fpu_slab",

					     sizeof(fpu_context_t),

					     FPU_CONTEXT_ALIGN,

					     NULL, NULL, 0);

#endif

	btree_create(&threads_btree);

}

/** Make thread ready

 *

 * Switch thread t to the ready state.

 *

 * @param t Thread to make ready.

 *

 */

void thread_ready(thread_t *t)

{

	cpu_t *cpu;

	runq_t *r;

	ipl_t ipl;

	int i, avg;

	ipl = interrupts_disable();

	spinlock_lock(&t->lock);

	ASSERT(! (t->state == Ready));

	i = (t->priority < RQ_COUNT -1) ? ++t->priority : t->priority;

	cpu = CPU;

	if (t->flags & X_WIRED) {

		cpu = t->cpu;

	}

	t->state = Ready;

	spinlock_unlock(&t->lock);

	/*

	 * Append t to respective ready queue on respective processor.

	 */

	r = &cpu->rq[i];

	spinlock_lock(&r->lock);

	list_append(&t->rq_link, &r->rq_head);

	r->n++;

	spinlock_unlock(&r->lock);

	atomic_inc(&nrdy);

	avg = atomic_get(&nrdy) / config.cpu_active;

	atomic_inc(&cpu->nrdy);

	interrupts_restore(ipl);

}

/** Destroy thread memory structure

 *

 * Detach thread from all queues, cpus etc. and destroy it.

 *

 * Assume thread->lock is held!!

 */

void thread_destroy(thread_t *t)

{

	bool destroy_task = false;	

	ASSERT(t->state == Exiting || t->state == Undead);

	ASSERT(t->task);

	ASSERT(t->cpu);

	spinlock_lock(&t->cpu->lock);

	if(t->cpu->fpu_owner==t)

		t->cpu->fpu_owner=NULL;

	spinlock_unlock(&t->cpu->lock);

	spinlock_unlock(&t->lock);

	spinlock_lock(&threads_lock);

	btree_remove(&threads_btree, (btree_key_t) ((uintptr_t ) t), NULL);

	spinlock_unlock(&threads_lock);

	/*

	 * Detach from the containing task.

	 */

	spinlock_lock(&t->task->lock);

	list_remove(&t->th_link);

	if (--t->task->refcount == 0) {

		t->task->accept_new_threads = false;

		destroy_task = true;

	}

	spinlock_unlock(&t->task->lock);	

	if (destroy_task)

		task_destroy(t->task);

	slab_free(thread_slab, t);

}

/** Create new thread

 *

 * Create a new thread.

 *

 * @param func  Thread's implementing function.

 * @param arg   Thread's implementing function argument.

 * @param task  Task to which the thread belongs.

 * @param flags Thread flags.

 * @param name  Symbolic name.

 *

 * @return New thread's structure on success, NULL on failure.

 *

 */

thread_t *thread_create(void (* func)(void *), void *arg, task_t *task, int flags, char *name)

{

	thread_t *t;

	ipl_t ipl;

	t = (thread_t *) slab_alloc(thread_slab, 0);

	if (!t)

		return NULL;

	thread_create_arch(t);

	/* Not needed, but good for debugging */

	memsetb((uintptr_t)t->kstack, THREAD_STACK_SIZE * 1<<STACK_FRAMES, 0);

	ipl = interrupts_disable();

	spinlock_lock(&tidlock);

	t->tid = ++last_tid;

	spinlock_unlock(&tidlock);

	interrupts_restore(ipl);

	context_save(&t->saved_context);

	context_set(&t->saved_context, FADDR(cushion), (uintptr_t) t->kstack, THREAD_STACK_SIZE);

	the_initialize((the_t *) t->kstack);

	ipl = interrupts_disable();

	t->saved_context.ipl = interrupts_read();

	interrupts_restore(ipl);

	memcpy(t->name, name, THREAD_NAME_BUFLEN);

	t->thread_code = func;

	t->thread_arg = arg;

	t->ticks = -1;

	t->priority = -1;		/* start in rq[0] */

	t->cpu = NULL;

	t->flags = 0;

	t->state = Entering;

	t->call_me = NULL;

	t->call_me_with = NULL;

	timeout_initialize(&t->sleep_timeout);

	t->sleep_interruptible = false;

	t->sleep_queue = NULL;

	t->timeout_pending = 0;

	t->in_copy_from_uspace = false;

	t->in_copy_to_uspace = false;

	t->interrupted = false;	

	t->join_type = None;

	t->detached = false;

	waitq_initialize(&t->join_wq);

	t->rwlock_holder_type = RWLOCK_NONE;

	t->task = task;

	t->fpu_context_exists = 0;

	t->fpu_context_engaged = 0;

	/*

	 * Attach to the containing task.

	 */

	ipl = interrupts_disable();	 

	spinlock_lock(&task->lock);

	if (!task->accept_new_threads) {

		spinlock_unlock(&task->lock);

		slab_free(thread_slab, t);

		interrupts_restore(ipl);

		return NULL;

	}

	list_append(&t->th_link, &task->th_head);

	if (task->refcount++ == 0)

		task->main_thread = t;

	spinlock_unlock(&task->lock);

	/*

	 * Register this thread in the system-wide list.

	 */

	spinlock_lock(&threads_lock);

	btree_insert(&threads_btree, (btree_key_t) ((uintptr_t) t), (void *) t, NULL);

	spinlock_unlock(&threads_lock);

	interrupts_restore(ipl);

	return t;

}

/** Terminate thread.

 *

 * End current thread execution and switch it to the exiting

 * state. All pending timeouts are executed.

 *

 */

void thread_exit(void)

{

	ipl_t ipl;

restart:

	ipl = interrupts_disable();

	spinlock_lock(&THREAD->lock);

	if (THREAD->timeout_pending) { /* busy waiting for timeouts in progress */

		spinlock_unlock(&THREAD->lock);

		interrupts_restore(ipl);

		goto restart;

	}

	THREAD->state = Exiting;

	spinlock_unlock(&THREAD->lock);

	scheduler();

	/* Not reached */

	while (1)

		;

}

/** Thread sleep

 *

 * Suspend execution of the current thread.

 *

 * @param sec Number of seconds to sleep.

 *

 */

void thread_sleep(uint32_t sec)

{

	thread_usleep(sec*1000000);

}

/** Wait for another thread to exit.

 *

 * @param t Thread to join on exit.

 * @param usec Timeout in microseconds.

 * @param flags Mode of operation.

 *

 * @return An error code from errno.h or an error code from synch.h.

 */

int thread_join_timeout(thread_t *t, uint32_t usec, int flags)

{

	ipl_t ipl;

	int rc;

	if (t == THREAD)

		return EINVAL;

	/*

	 * Since thread join can only be called once on an undetached thread,

	 * the thread pointer is guaranteed to be still valid.

	 */

	ipl = interrupts_disable();

	spinlock_lock(&t->lock);

	ASSERT(!t->detached);

	spinlock_unlock(&t->lock);

	interrupts_restore(ipl);

	rc = waitq_sleep_timeout(&t->join_wq, usec, flags);

	return rc;	

}

/** Detach thread.

 *

 * Mark the thread as detached, if the thread is already in the Undead state,

 * deallocate its resources.

 *

 * @param t Thread to be detached.

 */

void thread_detach(thread_t *t)

{

	ipl_t ipl;

	/*

	 * Since the thread is expected to not be already detached,

	 * pointer to it must be still valid.

	 */

	ipl = interrupts_disable();

	spinlock_lock(&t->lock);

	ASSERT(!t->detached);

	if (t->state == Undead) {

		thread_destroy(t);	/* unlocks &t->lock */

		interrupts_restore(ipl);

		return;

	} else {

		t->detached = true;

	}

	spinlock_unlock(&t->lock);

	interrupts_restore(ipl);

}

/** Thread usleep

 *

 * Suspend execution of the current thread.

 *

 * @param usec Number of microseconds to sleep.

 *

 */	

void thread_usleep(uint32_t usec)

{

	waitq_t wq;

	waitq_initialize(&wq);

	(void) waitq_sleep_timeout(&wq, usec, SYNCH_FLAGS_NON_BLOCKING);

}

/** Register thread out-of-context invocation

 *

 * Register a function and its argument to be executed

 * on next context switch to the current thread.

 *

 * @param call_me      Out-of-context function.

 * @param call_me_with Out-of-context function argument.

 *

 */

void thread_register_call_me(void (* call_me)(void *), void *call_me_with)

{

	ipl_t ipl;

	ipl = interrupts_disable();

	spinlock_lock(&THREAD->lock);

	THREAD->call_me = call_me;

	THREAD->call_me_with = call_me_with;

	spinlock_unlock(&THREAD->lock);

	interrupts_restore(ipl);

}

/** Print list of threads debug info */

void thread_print_list(void)

{

	link_t *cur;

	ipl_t ipl;

	/* Messing with thread structures, avoid deadlock */

	ipl = interrupts_disable();

	spinlock_lock(&threads_lock);

	for (cur = threads_btree.leaf_head.next; cur != &threads_btree.leaf_head; cur = cur->next) {

		btree_node_t *node;

		int i;

		node = list_get_instance(cur, btree_node_t, leaf_link);

		for (i = 0; i < node->keys; i++) {

			thread_t *t;

			t = (thread_t *) node->value[i];

			printf("%s: address=%#zx, tid=%zd, state=%s, task=%#zx, code=%#zx, stack=%#zx, cpu=",

				t->name, t, t->tid, thread_states[t->state], t->task, t->thread_code, t->kstack);

			if (t->cpu)

				printf("cpu%zd", t->cpu->id);

			else

				printf("none");

			if (t->state == Sleeping) {

				printf(", kst=%#zx", t->kstack);

				printf(", wq=%#zx", t->sleep_queue);

			}

			printf("\n");

		}

	}

	spinlock_unlock(&threads_lock);

	interrupts_restore(ipl);

}

/** Check whether thread exists.

 *

 * Note that threads_lock must be already held and

 * interrupts must be already disabled.

 *

 * @param t Pointer to thread.

 *

 * @return True if thread t is known to the system, false otherwise.

 */

bool thread_exists(thread_t *t)

{

	btree_node_t *leaf;

	return btree_search(&threads_btree, (btree_key_t) ((uintptr_t) t), &leaf) != NULL;

}

/** Process syscall to create new thread.

 *

 */

unative_t sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name)

{

	thread_t *t;

	char namebuf[THREAD_NAME_BUFLEN];

	uspace_arg_t *kernel_uarg;

	uint32_t tid;

	int rc;

	rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);

	if (rc != 0)

		return (unative_t) rc;

	kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);	

	rc = copy_from_uspace(kernel_uarg, uspace_uarg, sizeof(uspace_arg_t));

	if (rc != 0) {

		free(kernel_uarg);

		return (unative_t) rc;

	}

	if ((t = thread_create(uinit, kernel_uarg, TASK, 0, namebuf))) {

		tid = t->tid;

		thread_ready(t);

		return (unative_t) tid; 

	} else {

		free(kernel_uarg);

	}

	return (unative_t) ENOMEM;

}

/** Process syscall to terminate thread.

 *

 */

unative_t sys_thread_exit(int uspace_status)

{

	thread_exit();

	/* Unreachable */

	return 0;

}

/** @}

 */