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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;

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

/** @}

 */