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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.
 */

#ifndef __THREAD_H__
#define __THREAD_H__

#include <arch/thread.h>
#include <synch/spinlock.h>
#include <arch/context.h>
#include <fpu_context.h>
#include <arch/types.h>
#include <typedefs.h>
#include <time/timeout.h>
#include <synch/rwlock.h>
#include <config.h>
#include <list.h>

#define THREAD_STACK_SIZE   STACK_SIZE

#define THREAD_USER_STACK   1

enum state {
    Invalid,    /**< It is an error, if thread is found in this state. */
    Running,    /**< State of a thread that is currently executing on some CPU. */
    Sleeping,   /**< Thread in this state is waiting for an event. */
    Ready,      /**< State of threads in a run queue. */
    Entering,   /**< Threads are in this state before they are first readied. */
    Exiting     /**< After a thread calls thread_exit(), it is put into Exiting state. */
};

extern char *thread_states[];

#define X_WIRED     (1<<0)
#define X_STOLEN    (1<<1)

struct thread {
    link_t rq_link;             /**< Run queue link. */
    link_t wq_link;             /**< Wait queue link. */
    link_t th_link;             /**< Links to threads within containing task. */
    link_t threads_link;            /**< Link to the list of all threads. */
    
    /* items below are protected by lock */
    spinlock_t lock;

    void (* thread_code)(void *);       /**< Function implementing the thread. */
    void *thread_arg;           /**< Argument passed to thread_code() function. */

    context_t saved_context;        /**< From here, the stored context is restored when the thread is scheduled. */
    context_t sleep_timeout_context;    /**< From here, the stored failover context is restored when sleep times out. */

    waitq_t *sleep_queue;           /**< Wait queue in which this thread sleeps. */
    timeout_t sleep_timeout;        /**< Timeout used for timeoutable sleeping.  */
    volatile int timeout_pending;       /**< Flag signalling sleep timeout in progress. */

    fpu_context_t saved_fpu_context;
    int fpu_context_exists;

    /*
     * Defined only if thread doesn't run.
     * It means that fpu context is in CPU that last time executes this thread.
     * This disables migration
     */
    int fpu_context_engaged;

    rwlock_type_t rwlock_holder_type;

    void (* call_me)(void *);       /**< Funtion to be called in scheduler before the thread is put asleep. */
    void *call_me_with;         /**< Argument passed to call_me(). */

    state_t state;              /**< Thread's state. */
    int flags;              /**< Thread's flags. */
    
    cpu_t *cpu;             /**< Thread's CPU. */
    task_t *task;               /**< Containing task. */

    __u64 ticks;                /**< Ticks before preemption. */

    int pri;                /**< Thread's priority. Implemented as index of run queue. */
    __u32 tid;              /**< Thread ID. */
    
    ARCH_THREAD_DATA;           /**< Architecture-specific data. */

    __u8 *kstack;               /**< Thread's kernel stack. */
    __u8 *ustack;               /**< Thread's user stack. */
};

extern spinlock_t threads_lock;         /**< Lock protecting threads_head list. */
extern link_t threads_head;         /**< List of all threads in the system. */

static void cushion(void);

extern void thread_init(void);
extern thread_t *thread_create(void (* func)(void *), void *arg, task_t *task, int flags);
extern void thread_ready(thread_t *t);
extern void thread_exit(void);

extern void thread_sleep(__u32 sec);
extern void thread_usleep(__u32 usec);

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

#endif