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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

/** @}

 */