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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
 */

#ifndef KERN_THREAD_H_
#define KERN_THREAD_H_

#include <synch/waitq.h>
#include <proc/task.h>
#include <time/timeout.h>
#include <cpu.h>
#include <synch/rwlock.h>
#include <adt/btree.h>
#include <mm/slab.h>
#include <arch/cpu.h>
#include <mm/tlb.h>
#include <proc/uarg.h>

#define THREAD_STACK_SIZE   STACK_SIZE
#define THREAD_NAME_BUFLEN  20

extern char *thread_states[];

/* Thread flags */

/** Thread cannot be migrated to another CPU. */
#define THREAD_FLAG_WIRED   (1 << 0)
/** Thread was migrated to another CPU and has not run yet. */
#define THREAD_FLAG_STOLEN  (1 << 1)
/** Thread executes in userspace. */
#define THREAD_FLAG_USPACE  (1 << 2)

/** Thread states. */
typedef enum {
    /** It is an error, if thread is found in this state. */
    Invalid,
    /** State of a thread that is currently executing on some CPU. */
    Running,
    /** Thread in this state is waiting for an event. */
    Sleeping,
    /** State of threads in a run queue. */
    Ready,
    /** Threads are in this state before they are first readied. */
    Entering,
    /** After a thread calls thread_exit(), it is put into Exiting state. */
    Exiting,
    /** Threads that were not detached but exited are in the Undead state. */
    Undead
} state_t;

/** Join types. */
typedef enum {
    None,
    TaskClnp,   /**< The thread will be joined by ktaskclnp thread. */
    TaskGC      /**< The thread will be joined by ktaskgc thread. */
} thread_join_type_t;

/** Thread structure. There is one per thread. */
typedef 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. */
    
    /** Lock protecting thread structure.
     *
     * Protects the whole thread structure except list links above.
     */
    SPINLOCK_DECLARE(lock);

    char name[THREAD_NAME_BUFLEN];

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

    /**
     * From here, the stored context is restored when the thread is
     * scheduled.
     */
    context_t saved_context;
    /**
     * From here, the stored timeout context is restored when sleep times
     * out.
     */
    context_t sleep_timeout_context;
    /**
     * From here, the stored interruption context is restored when sleep is
     * interrupted.
     */
    context_t sleep_interruption_context;

    /** If true, the thread can be interrupted from sleep. */
    bool sleep_interruptible;
    /** Wait queue in which this thread sleeps. */
    waitq_t *sleep_queue;
    /** Timeout used for timeoutable sleeping.  */
    timeout_t sleep_timeout;
    /** Flag signalling sleep timeout in progress. */
    volatile int timeout_pending;

    /**
     * True if this thread is executing copy_from_uspace().
     * False otherwise.
     */
    bool in_copy_from_uspace;
    /**
     * True if this thread is executing copy_to_uspace().
     * False otherwise.
     */
    bool in_copy_to_uspace;
    
    /**
     * If true, the thread will not go to sleep at all and will call
     * thread_exit() before returning to userspace.
     */
    bool interrupted;           
    
    /** Who joinins the thread. */
    thread_join_type_t join_type;
    /** If true, thread_join_timeout() cannot be used on this thread. */
    bool detached;
    /** Waitq for thread_join_timeout(). */
    waitq_t join_wq;

    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;

    /** Callback fired in scheduler before the thread is put asleep. */
    void (* call_me)(void *);
    /** Argument passed to call_me(). */
    void *call_me_with;

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

    /** Ticks before preemption. */
    uint64_t ticks;
    
    /** Thread accounting. */
    uint64_t cycles;
    /** Last sampled cycle. */
    uint64_t last_cycle;
    /** Thread doesn't affect accumulated accounting. */    
    bool uncounted;

    /** Thread's priority. Implemented as index to CPU->rq */
    int priority;
    /** Thread ID. */
    uint32_t tid;
    
    /** Architecture-specific data. */
    thread_arch_t arch;

    /** Thread's kernel stack. */
    uint8_t *kstack;
} thread_t;

/** Thread list lock.
 *
 * This lock protects all link_t structures chained in threads_head.
 * Must be acquired before T.lock for each T of type thread_t.
 *
 */
SPINLOCK_EXTERN(threads_lock);

/** B+tree containing all threads. */
extern btree_t threads_btree;

extern void thread_init(void);
extern thread_t *thread_create(void (* func)(void *), void *arg, task_t *task,
    int flags, char *name, bool uncounted);
extern void thread_ready(thread_t *t);
extern void thread_exit(void) __attribute__((noreturn));

#ifndef thread_create_arch
extern void thread_create_arch(thread_t *t);
#endif
#ifndef thr_constructor_arch
extern void thr_constructor_arch(thread_t *t);
#endif
#ifndef thr_destructor_arch
extern void thr_destructor_arch(thread_t *t);
#endif

extern void thread_sleep(uint32_t sec);
extern void thread_usleep(uint32_t usec);

#define thread_join(t) \
    thread_join_timeout((t), SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE)
extern int thread_join_timeout(thread_t *t, uint32_t usec, int flags);
extern void thread_detach(thread_t *t);

extern void thread_register_call_me(void (* call_me)(void *),
    void *call_me_with);
extern void thread_print_list(void);
extern void thread_destroy(thread_t *t);
extern void thread_update_accounting(void);
extern bool thread_exists(thread_t *t);

/** Fpu context slab cache. */
extern slab_cache_t *fpu_context_slab;

/* Thread syscall prototypes. */
unative_t sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name);
unative_t sys_thread_exit(int uspace_status);
unative_t sys_thread_get_id(void);

#endif

/** @}
 */