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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_TASK_H_

#define KERN_TASK_H_

#include <cpu.h>

#include <synch/spinlock.h>

#include <synch/mutex.h>

#include <synch/rwlock.h>

#include <synch/futex.h>

#include <adt/btree.h>

#include <adt/list.h>

#include <security/cap.h>

#include <arch/proc/task.h>

#include <arch/proc/thread.h>

#include <arch/context.h>

#include <arch/fpu_context.h>

#include <arch/cpu.h>

#include <mm/tlb.h>

#include <proc/scheduler.h>

#define IPC_MAX_PHONES  16

#define THREAD_NAME_BUFLEN  20

struct answerbox;

struct task;

struct thread;

typedef enum {

    IPC_PHONE_FREE = 0,     /**< Phone is free and can be allocated */

    IPC_PHONE_CONNECTING,   /**< Phone is connecting somewhere */

    IPC_PHONE_CONNECTED,    /**< Phone is connected */

    IPC_PHONE_HUNGUP,   /**< Phone is hung up, waiting for answers to come */

    IPC_PHONE_SLAMMED       /**< Phone was hungup from server */

} ipc_phone_state_t;

/** Structure identifying phone (in TASK structure) */

typedef struct {

    SPINLOCK_DECLARE(lock);

    link_t link;

    struct answerbox *callee;

    ipc_phone_state_t state;

    atomic_t active_calls;

} phone_t;

typedef struct answerbox {

    SPINLOCK_DECLARE(lock);

    struct task *task;

    waitq_t wq;

    link_t connected_phones;    /**< Phones connected to this answerbox */

    link_t calls;           /**< Received calls */

    link_t dispatched_calls;    /* Should be hash table in the future */

    link_t answers;         /**< Answered calls */

    SPINLOCK_DECLARE(irq_lock);

    link_t irq_notifs;          /**< Notifications from IRQ handlers */

    link_t irq_head;        /**< IRQs with notifications to this answerbox. */

} answerbox_t;

/** Task structure. */

typedef struct task {

    /** Task lock.

     *

     * Must be acquired before threads_lock and thread lock of any of its threads.

     */

    SPINLOCK_DECLARE(lock);

    char *name;

    struct thread *main_thread; /**< Pointer to the main thread. */

    link_t th_head;     /**< List of threads contained in this task. */

    as_t *as;       /**< Address space. */

    task_id_t taskid;   /**< Unique identity of task */

    context_id_t context;   /**< Task security context */

    /** If this is true, new threads can become part of the task. */

    bool accept_new_threads;

    count_t refcount;   /**< Number of references (i.e. threads). */

    cap_t capabilities; /**< Task capabilities. */

    /* IPC stuff */

    answerbox_t answerbox;  /**< Communication endpoint */

    phone_t phones[IPC_MAX_PHONES];

    atomic_t active_calls;  /**< Active asynchronous messages.

                 *   It is used for limiting uspace to

                 *   certain extent. */

    task_arch_t arch;   /**< Architecture specific task data. */

    /**

     * Serializes access to the B+tree of task's futexes. This mutex is

     * independent on the task spinlock.

     */

    mutex_t futexes_lock;

    btree_t futexes;    /**< B+tree of futexes referenced by this task. */

    uint64_t cycles;    /**< Accumulated accounting. */

} task_t;

typedef void (* timeout_handler_t)(void *arg);

typedef struct {

    SPINLOCK_DECLARE(lock);

    link_t link;            /**< Link to the list of active timeouts on THE->cpu */

    uint64_t ticks;         /**< Timeout will be activated in this amount of clock() ticks. */

    timeout_handler_t handler;  /**< Function that will be called on timeout activation. */

    void *arg;          /**< Argument to be passed to handler() function. */

    cpu_t *cpu;         /**< On which processor is this timeout registered. */

} timeout_t;

/** Thread states. */

typedef enum {

    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. */

    Undead      /**< Threads that were not detached but exited are in the Undead state. */

} 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];

    void (* thread_code)(void *);       /**< Function implementing the thread. */

    void *thread_arg;           /**< Argument passed to thread_code() function. */

    /** 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;

    bool sleep_interruptible;       /**< If true, the thread can be interrupted from sleep. */

    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. */

    /** 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;          

    thread_join_type_t  join_type;  /**< Who joinins the thread. */

    bool detached;              /**< If true, thread_join_timeout() cannot be used on this thread. */

    waitq_t join_wq;            /**< Waitq for thread_join_timeout(). */

    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. */

    uint64_t ticks;             /**< Ticks before preemption. */

    uint64_t cycles;            /**< Thread accounting. */

    uint64_t last_cycle;        /**< Last sampled cycle. */

    bool uncounted;             /**< Thread doesn't affect accumulated accounting. */

    int priority;               /**< Thread's priority. Implemented as index to CPU->rq */

    uint32_t tid;               /**< Thread ID. */

    thread_arch_t arch;         /**< Architecture-specific data. */

    uint8_t *kstack;            /**< Thread's kernel stack. */

} thread_t;

SPINLOCK_EXTERN(tasks_lock);

extern btree_t tasks_btree;

extern void task_init(void);

extern task_t *task_create(as_t *as, char *name);

extern void task_destroy(task_t *t);

extern task_t *task_run_program(void *program_addr, char *name);

extern task_t *task_find_by_id(task_id_t id);

extern int task_kill(task_id_t id);

extern uint64_t task_get_accounting(task_t *t);

extern void cap_set(task_t *t, cap_t caps);

extern cap_t cap_get(task_t *t);

#ifndef task_create_arch

extern void task_create_arch(task_t *t);

#endif

#ifndef task_destroy_arch

extern void task_destroy_arch(task_t *t);

#endif

extern unative_t sys_task_get_id(task_id_t *uspace_task_id);

#endif

/** @}

 */