/*
 * Copyright (c) 2001-2007 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/spinlock.h>
#include <synch/rcu_types.h>
#include <adt/avl.h>
#include <mm/slab.h>
#include <arch/cpu.h>
#include <mm/tlb.h>
#include <abi/proc/uarg.h>
#include <udebug/udebug.h>
#include <abi/proc/thread.h>
#include <abi/sysinfo.h>
#include <arch.h>

#define THREAD              THE->thread

#define THREAD_NAME_BUFLEN  20

extern const char *thread_states[];

/* Thread flags */
typedef enum {
	THREAD_FLAG_NONE = 0,
	/** Thread executes in user space. */
	THREAD_FLAG_USPACE = (1 << 0),
	/** Thread will be attached by the caller. */
	THREAD_FLAG_NOATTACH = (1 << 1),
	/** Thread accounting doesn't affect accumulated task accounting. */
	THREAD_FLAG_UNCOUNTED = (1 << 2)
} thread_flags_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. */

	/** Threads linkage to the threads_tree. */
	avltree_node_t threads_tree_node;

	/** Lock protecting thread structure.
	 *
	 * Protects the whole thread structure except list links above.
	 */
	IRQ_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;

	/**
	 * If true, and this thread's sleep returns without a wakeup
	 * (timed out or interrupted), waitq ignores the next wakeup.
	 * This is necessary for futex to be able to handle those conditions.
	 */
	bool sleep_composable;

	/** 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 bool 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;

	/** If true, thread_join_timeout() cannot be used on this thread. */
	bool detached;
	/** Waitq for thread_join_timeout(). */
	waitq_t join_wq;
	/** Link used in the joiner_head list. */
	link_t joiner_link;

	fpu_context_t *saved_fpu_context;
	bool 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.
	 */
	bool fpu_context_engaged;

	/* The thread will not be migrated if nomigrate is non-zero. */
	unsigned int nomigrate;

	/** Thread state. */
	state_t state;

	/** Thread CPU. */
	cpu_t *cpu;
	/** Containing task. */
	task_t *task;
	/** Thread is wired to CPU. */
	bool wired;
	/** Thread was migrated to another CPU and has not run yet. */
	bool stolen;
	/** Thread is executed in user space. */
	bool uspace;

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

	/** Thread accounting. */
	uint64_t ucycles;
	uint64_t kcycles;
	/** 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;

	/** Work queue this thread belongs to or NULL. Immutable. */
	struct work_queue *workq;
	/** Links work queue threads. Protected by workq->lock. */
	link_t workq_link;
	/** True if the worker was blocked and is not running. Use thread->lock. */
	bool workq_blocked;
	/** True if the worker will block in order to become idle. Use workq->lock. */
	bool workq_idling;

	/** RCU thread related data. Protected by its own locks. */
	rcu_thread_data_t rcu;

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

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

#ifdef CONFIG_UDEBUG
	/**
	 * If true, the scheduler will print a stack trace
	 * to the kernel console upon scheduling this thread.
	 */
	bool btrace;

	/** Debugging stuff */
	udebug_thread_t udebug;
#endif /* CONFIG_UDEBUG */
} thread_t;

/** Thread list lock.
 *
 * This lock protects the threads_tree.
 * Must be acquired before T.lock for each T of type thread_t.
 *
 */
IRQ_SPINLOCK_EXTERN(threads_lock);

/** AVL tree containing all threads. */
extern avltree_t threads_tree;

extern void thread_init(void);
extern thread_t *thread_create(void (*)(void *), void *, task_t *,
    thread_flags_t, const char *);
extern void thread_wire(thread_t *, cpu_t *);
extern void thread_attach(thread_t *, task_t *);
extern void thread_ready(thread_t *);
extern void thread_exit(void) __attribute__((noreturn));
extern void thread_interrupt(thread_t *);
extern bool thread_interrupted(thread_t *);

#ifndef thread_create_arch
extern void thread_create_arch(thread_t *);
#endif

#ifndef thr_constructor_arch
extern void thr_constructor_arch(thread_t *);
#endif

#ifndef thr_destructor_arch
extern void thr_destructor_arch(thread_t *);
#endif

extern void thread_sleep(uint32_t);
extern void thread_usleep(uint32_t);

#define thread_join(t) \
	thread_join_timeout((t), SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE)

extern errno_t thread_join_timeout(thread_t *, uint32_t, unsigned int);
extern void thread_detach(thread_t *);

extern void thread_print_list(bool);
extern void thread_destroy(thread_t *, bool);
extern thread_t *thread_find_by_id(thread_id_t);
extern void thread_update_accounting(bool);
extern bool thread_exists(thread_t *);

extern void thread_migration_disable(void);
extern void thread_migration_enable(void);

#ifdef CONFIG_UDEBUG
extern void thread_stack_trace(thread_id_t);
#endif

/** Fpu context slab cache. */
extern slab_cache_t *fpu_context_cache;

/* Thread syscall prototypes. */
extern sys_errno_t sys_thread_create(uspace_arg_t *, char *, size_t,
    thread_id_t *);
extern sys_errno_t sys_thread_exit(int);
extern sys_errno_t sys_thread_get_id(thread_id_t *);
extern sys_errno_t sys_thread_usleep(uint32_t);
extern sys_errno_t sys_thread_udelay(uint32_t);

#endif

/** @}
 */
