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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.

 *

 * When using this flag, the caller must set cpu in the thread_t

 * structure manually before calling thread_ready (even on uniprocessor).

 */

#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. */

    thread_id_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. */

extern unative_t sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name, thread_id_t *uspace_thread_id);

extern unative_t sys_thread_exit(int uspace_status);

extern unative_t sys_thread_get_id(thread_id_t *uspace_thread_id);

#endif

/** @}

 */