source: mainline/kernel/generic/include/proc/task.h@ 3bf4143

/*
 * 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.
         */
        unsigned 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

/** @}
 */