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/*3D
 * 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 <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;

/** CPU structure.
 *
 * There is one structure like this for every processor.
 */
typedef struct {
    SPINLOCK_DECLARE(lock);

    tlb_shootdown_msg_t tlb_messages[TLB_MESSAGE_QUEUE_LEN];
    count_t tlb_messages_count;
    
    context_t saved_context;

    atomic_t nrdy;
    runq_t rq[RQ_COUNT];
    volatile count_t needs_relink;

    SPINLOCK_DECLARE(timeoutlock);
    link_t timeout_active_head;

    count_t missed_clock_ticks; /**< When system clock loses a tick, it is recorded here
                         so that clock() can react. This variable is
                         CPU-local and can be only accessed when interrupts
                         are disabled. */

    /**
     * Processor ID assigned by kernel.
     */
    int id;
    
    int active;
    int tlb_active;

    uint16_t frequency_mhz;
    uint32_t delay_loop_const;

    cpu_arch_t arch;

    struct thread *fpu_owner;
    
    /**
     * Stack used by scheduler when there is no running thread.
     */
    uint8_t *stack;
} cpu_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;

extern spinlock_t 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

/** @}
 */