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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.

 */

#include <proc/scheduler.h>

#include <proc/thread.h>

#include <proc/task.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/list.h>

#include <typedefs.h>

#include <time/clock.h>

#include <adt/list.h>

#include <config.h>

#include <arch/interrupt.h>

#include <smp/ipi.h>

#include <arch/faddr.h>

#include <arch/atomic.h>

#include <memstr.h>

#include <print.h>

#include <mm/slab.h>

#include <debug.h>

char *thread_states[] = {"Invalid", "Running", "Sleeping", "Ready", "Entering", "Exiting"}; /**< Thread states */

SPINLOCK_INITIALIZE(threads_lock);	/**< Lock protecting threads_head list. For locking rules, see declaration thereof. */

LIST_INITIALIZE(threads_head);		/**< List of all threads. */

SPINLOCK_INITIALIZE(tidlock);

__u32 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 */

	before_thread_runs();

	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;

	pfn_t pfn;

	int status;

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

	link_initialize(&t->rq_link);

	link_initialize(&t->wq_link);

	link_initialize(&t->th_link);

	link_initialize(&t->threads_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	

	pfn = frame_alloc_rc(ONE_FRAME, FRAME_KA | kmflags,&status);

	if (status) {

#ifdef ARCH_HAS_FPU

		if (t->saved_fpu_context)

			slab_free(fpu_context_slab,t->saved_fpu_context);

#endif

		return -1;

	}

	t->kstack = (__u8 *)PA2KA(PFN2ADDR(pfn));

	return 0;

}

/** Destruction of thread_t object */

static int thr_destructor(void *obj)

{

	thread_t *t = (thread_t *)obj;

	frame_free(ADDR2PFN(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

}

/** 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);

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

	cpu = CPU;

	if (t->flags & X_WIRED) {

		cpu = t->cpu;

	}

	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)

{

	ASSERT(t->state == Exiting);

	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);

	/*

	 * Detach from the containing task.

	 */

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

	list_remove(&t->th_link);

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

	spinlock_unlock(&t->lock);

	spinlock_lock(&threads_lock);

	list_remove(&t->threads_link);

	spinlock_unlock(&threads_lock);

	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.

 *

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

 *

 */

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

{

	thread_t *t;

	ipl_t ipl;

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

	if (!t)

		return NULL;

	/* Not needed, but good for debugging */

	memsetb((__address)t->kstack, THREAD_STACK_SIZE, 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), (__address) t->kstack, THREAD_STACK_SIZE);

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

	ipl = interrupts_disable();

	t->saved_context.ipl = interrupts_read();

	interrupts_restore(ipl);

	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_queue = NULL;

	t->timeout_pending = 0;

	t->rwlock_holder_type = RWLOCK_NONE;

	t->task = task;

	t->fpu_context_exists = 0;

	t->fpu_context_engaged = 0;

	/*

	 * Register this thread in the system-wide list.

	 */

	ipl = interrupts_disable();

	spinlock_lock(&threads_lock);

	list_append(&t->threads_link, &threads_head);

	spinlock_unlock(&threads_lock);

	/*

	 * Attach to the containing task.

	 */

	spinlock_lock(&task->lock);

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

	spinlock_unlock(&task->lock);

	interrupts_restore(ipl);

	return t;

}

/** Make thread exiting

 *

 * 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();

}

/** Thread sleep

 *

 * Suspend execution of the current thread.

 *

 * @param sec Number of seconds to sleep.

 *

 */

void thread_sleep(__u32 sec)

{

	thread_usleep(sec*1000000);

}

/** Thread usleep

 *

 * Suspend execution of the current thread.

 *

 * @param usec Number of microseconds to sleep.

 *

 */	

void thread_usleep(__u32 usec)

{

	waitq_t wq;

	waitq_initialize(&wq);

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

	thread_t *t;

	ipl_t ipl;

	/* Messing with thread structures, avoid deadlock */

	ipl = interrupts_disable();

	spinlock_lock(&threads_lock);

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

		t = list_get_instance(cur, thread_t, threads_link);

		printf("Thr: %d(%s) ", t->tid, thread_states[t->state]);

		if (t->cpu)

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

		printf("\n");

	}

	spinlock_unlock(&threads_lock);

	interrupts_enable();

}