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/*  thread.h

 *

 *  This include file contains all constants and structures associated

 *  with the thread control block.

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: thread.h,v 1.2 2001-09-27 11:59:32 chris Exp $

 */

#ifndef __THREAD_h

#define __THREAD_h

#ifdef __cplusplus

extern "C" {

#endif

#include <rtems/score/context.h>

#include <rtems/score/cpu.h>

#if defined(RTEMS_MULTIPROCESSING)

#include <rtems/score/mppkt.h>

#endif

#include <rtems/score/object.h>

#include <rtems/score/priority.h>

#include <rtems/score/stack.h>

#include <rtems/score/states.h>

#include <rtems/score/tod.h>

#include <rtems/score/tqdata.h>

#include <rtems/score/watchdog.h>

/*

 *  The following defines the "return type" of a thread.

 *

 *  NOTE:  This cannot always be right.  Some APIs have void

 *         tasks/threads, others return pointers, others may

 *         return a numeric value.  Hopefully a pointer is

 *         always at least as big as an unsigned32. :)

 */

typedef void *Thread;

/*

 *  The following defines the ways in which the entry point for a

 *  thread can be invoked.  Basically, it can be passed any

 *  combination/permutation of a pointer and an unsigned32 value.

 *

 *  NOTE: For now, we are ignoring the return type.

 */

typedef enum {

  THREAD_START_NUMERIC,

  THREAD_START_POINTER,

  THREAD_START_BOTH_POINTER_FIRST,

  THREAD_START_BOTH_NUMERIC_FIRST

} Thread_Start_types;

typedef Thread ( *Thread_Entry )();   /* basic type */

typedef Thread ( *Thread_Entry_numeric )( unsigned32 );

typedef Thread ( *Thread_Entry_pointer )( void * );

typedef Thread ( *Thread_Entry_both_pointer_first )( void *, unsigned32 );

typedef Thread ( *Thread_Entry_both_numeric_first )( unsigned32, void * );

/*

 *  The following lists the algorithms used to manage the thread cpu budget.

 *

 *  Reset Timeslice:   At each context switch, reset the time quantum.

 *  Exhaust Timeslice: Only reset the quantum once it is consumed.

 *  Callout:           Execute routine when budget is consumed.

 */

typedef enum {

  THREAD_CPU_BUDGET_ALGORITHM_NONE,

  THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE,

  THREAD_CPU_BUDGET_ALGORITHM_EXHAUST_TIMESLICE,

  THREAD_CPU_BUDGET_ALGORITHM_CALLOUT

}  Thread_CPU_budget_algorithms;

typedef struct Thread_Control_struct Thread_Control;

typedef void (*Thread_CPU_budget_algorithm_callout )( Thread_Control * );

/*

 *  Per task variable structure

 */

struct rtems_task_variable_tt;

struct rtems_task_variable_tt {

  struct rtems_task_variable_tt  *next;

  void                          **ptr;

  void                           *gval;

  void                           *tval;

  void                          (*dtor)(void *);

};

typedef struct rtems_task_variable_tt   rtems_task_variable_t;

/*

 *  The following structure contains the information which defines

 *  the starting state of a thread.

 */

typedef struct {

  Thread_Entry         entry_point;      /* starting thread address         */

  Thread_Start_types   prototype;        /* how task is invoked             */

  void                *pointer_argument; /* pointer argument                */

  unsigned32           numeric_argument; /* numeric argument                */

                                         /* initial execution modes         */

  boolean              is_preemptible;

  Thread_CPU_budget_algorithms          budget_algorithm;

  Thread_CPU_budget_algorithm_callout   budget_callout;

  unsigned32           isr_level;

  Priority_Control     initial_priority; /* initial priority                */

  boolean              core_allocated_stack;

  Stack_Control        Initial_stack;    /* stack information               */

  void                *fp_context;       /* initial FP context area address */

  void                *stack;            /* initial stack area address      */

}   Thread_Start_information;

/*

 *  The following structure contains the information necessary to manage

 *  a thread which it is  waiting for a resource.

 */

#define THREAD_STATUS_PROXY_BLOCKING 0x1111111

typedef struct {

  Objects_Id            id;              /* waiting on this object       */

  unsigned32            count;           /* "generic" fields to be used */

  void                 *return_argument; /*   when blocking */

  void                 *return_argument_1;

  unsigned32            option;

  /*

   *  NOTE: The following assumes that all API return codes can be

   *        treated as an unsigned32.

   */

  unsigned32            return_code;     /* status for thread awakened   */

  Chain_Control         Block2n;         /* 2 - n priority blocked chain */

  Thread_queue_Control *queue;           /* pointer to thread queue      */

}   Thread_Wait_information;

/*

 *  The following defines the control block used to manage

 *  each thread proxy.

 *

 *  NOTE: It is critical that proxies and threads have identical

 *        memory images for the shared part.

 */

typedef struct {

  Objects_Control          Object;

  States_Control           current_state;

  Priority_Control         current_priority;

  Priority_Control         real_priority;

  unsigned32               resource_count;

  Thread_Wait_information  Wait;

  Watchdog_Control         Timer;

#if defined(RTEMS_MULTIPROCESSING)

  MP_packet_Prefix        *receive_packet;

#endif

     /****************** end of common block ********************/

  Chain_Node               Active;

}   Thread_Proxy_control;

/*

 *  The following record defines the control block used

 *  to manage each thread.

 *

 *  NOTE: It is critical that proxies and threads have identical

 *        memory images for the shared part.

 */

typedef enum {

  THREAD_API_RTEMS,

  THREAD_API_POSIX,

  THREAD_API_ITRON

}  Thread_APIs;

#define THREAD_API_FIRST THREAD_API_RTEMS

#define THREAD_API_LAST  THREAD_API_ITRON

struct Thread_Control_struct {

  Objects_Control                       Object;

  States_Control                        current_state;

  Priority_Control                      current_priority;

  Priority_Control                      real_priority;

  unsigned32                            resource_count;

  Thread_Wait_information               Wait;

  Watchdog_Control                      Timer;

#if defined(RTEMS_MULTIPROCESSING)

  MP_packet_Prefix                     *receive_packet;

#endif

     /****************** end of common block ********************/

  unsigned32                            suspend_count;

  boolean                               is_global;

  boolean                               do_post_task_switch_extension;

  boolean                               is_preemptible;

  void                                 *rtems_ada_self;

  unsigned32                            cpu_time_budget;

  Thread_CPU_budget_algorithms          budget_algorithm;

  Thread_CPU_budget_algorithm_callout   budget_callout;

  unsigned32                            ticks_executed;

  Chain_Control                        *ready;

  Priority_Information                  Priority_map;

  Thread_Start_information              Start;

  Context_Control                       Registers;

  void                                 *fp_context;

  void                                 *API_Extensions[ THREAD_API_LAST + 1 ];

  void                                **extensions;

  rtems_task_variable_t                *task_variables;

};

/*

 *  Self for the GNU Ada Run-Time

 */

SCORE_EXTERN void *rtems_ada_self;

/*

 *  The following defines the information control block used to

 *  manage this class of objects.

 */

SCORE_EXTERN Objects_Information _Thread_Internal_information;

/*

 *  The following define the thread control pointers used to access

 *  and manipulate the idle thread.

 */

SCORE_EXTERN Thread_Control *_Thread_Idle;

/*

 *  The following context area contains the context of the "thread"

 *  which invoked the start multitasking routine.  This context is

 *  restored as the last action of the stop multitasking routine.  Thus

 *  control of the processor can be returned to the environment

 *  which initiated the system.

 */

SCORE_EXTERN Context_Control _Thread_BSP_context;

/*

 *  The following declares the dispatch critical section nesting

 *  counter which is used to prevent context switches at inopportune

 *  moments.

 */

SCORE_EXTERN volatile unsigned32 _Thread_Dispatch_disable_level;

/*

 *  If this is non-zero, then the post-task switch extension

 *  is run regardless of the state of the per thread flag.

 */

SCORE_EXTERN unsigned32 _Thread_Do_post_task_switch_extension;

/*

 *  The following holds how many user extensions are in the system.  This

 *  is used to determine how many user extension data areas to allocate

 *  per thread.

 */

SCORE_EXTERN unsigned32 _Thread_Maximum_extensions;

/*

 *  The following is used to manage the length of a timeslice quantum.

 */

SCORE_EXTERN unsigned32 _Thread_Ticks_per_timeslice;

/*

 *  The following points to the array of FIFOs used to manage the

 *  set of ready threads.

 */

SCORE_EXTERN Chain_Control *_Thread_Ready_chain;

/*

 *  The following points to the thread which is currently executing.

 *  This thread is implicitly manipulated by numerous directives.

 */

SCORE_EXTERN Thread_Control *_Thread_Executing;

/*

 *  The following points to the highest priority ready thread

 *  in the system.  Unless the current thread is not preemptibl,

 *  then this thread will be context switched to when the next

 *  dispatch occurs.

 */

SCORE_EXTERN Thread_Control *_Thread_Heir;

/*

 *  The following points to the thread whose floating point

 *  context is currently loaded.

 */

SCORE_EXTERN Thread_Control *_Thread_Allocated_fp;

/*

 *  _Thread_Handler_initialization

 *

 *  DESCRIPTION:

 *

 *  This routine performs the initialization necessary for this handler.

 */

void _Thread_Handler_initialization (

  unsigned32   ticks_per_timeslice,

  unsigned32   maximum_extensions,

  unsigned32   maximum_proxies

);

/*

 *  _Thread_Create_idle

 *

 *  DESCRIPTION:

 *

 *  This routine creates the idle thread.

 *

 *  WARNING!! No thread should be created before this one.

 */

void _Thread_Create_idle( void );

/*

 *  _Thread_Start_multitasking

 *

 *  DESCRIPTION:

 *

 *  This routine initiates multitasking.  It is invoked only as

 *  part of initialization and its invocation is the last act of

 *  the non-multitasking part of the system initialization.

 */

void _Thread_Start_multitasking( void );

/*

 *  _Thread_Dispatch

 *

 *  DESCRIPTION:

 *

 *  This routine is responsible for transferring control of the

 *  processor from the executing thread to the heir thread.  As part

 *  of this process, it is responsible for the following actions:

 *

 *     + saving the context of the executing thread

 *     + restoring the context of the heir thread

 *     + dispatching any signals for the resulting executing thread

 */

void _Thread_Dispatch( void );

/*

 *  _Thread_Stack_Allocate

 *

 *  DESCRIPTION:

 *

 *  Allocate the requested stack space for the thread.

 *  return the actual size allocated after any adjustment

 *  or return zero if the allocation failed.

 *  Set the Start.stack field to the address of the stack

 *

 *  NOTES: NONE

 *

 */

unsigned32 _Thread_Stack_Allocate(

  Thread_Control *the_thread,

  unsigned32 stack_size

);

/*

 *  _Thread_Stack_Free

 *

 *  DESCRIPTION:

 *

 *  Deallocate the Thread's stack.

 *  NOTES: NONE

 *

 */

void _Thread_Stack_Free(

  Thread_Control *the_thread

);

/*

 *  _Thread_Initialize

 *

 *  DESCRIPTION:

 *

 *  This routine initializes the specified the thread.  It allocates

 *  all memory associated with this thread.  It completes by adding

 *  the thread to the local object table so operations on this

 *  thread id are allowed.

 *

 *  NOTES:

 *

 *  If stack_area is NULL, it is allocated from the workspace.

 *

 *  If the stack is allocated from the workspace, then it is guaranteed to be

 *  of at least minimum size.

 */

boolean _Thread_Initialize(

  Objects_Information                  *information,

  Thread_Control                       *the_thread,

  void                                 *stack_area,

  unsigned32                            stack_size,

  boolean                               is_fp,

  Priority_Control                      priority,

  boolean                               is_preemptible,

  Thread_CPU_budget_algorithms          budget_algorithm,

  Thread_CPU_budget_algorithm_callout   budget_callout,

  unsigned32                            isr_level,

  Objects_Name                          name

);

/*

 *  _Thread_Start

 *

 *  DESCRIPTION:

 *

 *  This routine initializes the executable information for a thread

 *  and makes it ready to execute.  After this routine executes, the

 *  thread competes with all other threads for CPU time.

 */

boolean _Thread_Start(

  Thread_Control           *the_thread,

  Thread_Start_types        the_prototype,

  void                     *entry_point,

  void                     *pointer_argument,

  unsigned32                numeric_argument

);

/*

 *  _Thread_Restart

 *

 *  DESCRIPTION:

 *

 *  This support routine restarts the specified task in a way that the

 *  next time this thread executes, it will begin execution at its

 *  original starting point.

 */

/* XXX multiple task arg profiles */

boolean _Thread_Restart(

  Thread_Control           *the_thread,

  void                     *pointer_argument,

  unsigned32                numeric_argument

);

/*

 *  _Thread_Reset

 *

 *  DESCRIPTION:

 *

 *  This routine resets a thread to its initial state but does

 *  not restart it.

 */

void _Thread_Reset(

  Thread_Control      *the_thread,

  void                *pointer_argument,

  unsigned32           numeric_argument

);

/*

 *  _Thread_Close

 *

 *  DESCRIPTION:

 *

 *  This routine frees all memory associated with the specified

 *  thread and removes it from the local object table so no further

 *  operations on this thread are allowed.

 */

void _Thread_Close(

  Objects_Information  *information,

  Thread_Control       *the_thread

);

/*

 *  _Thread_Ready

 *

 *  DESCRIPTION:

 *

 *  This routine removes any set states for the_thread.  It performs

 *  any necessary scheduling operations including the selection of

 *  a new heir thread.

 */

void _Thread_Ready(

  Thread_Control *the_thread

);

/*

 *  _Thread_Clear_state

 *

 *  DESCRIPTION:

 *

 *  This routine clears the indicated STATES for the_thread.  It performs

 *  any necessary scheduling operations including the selection of

 *  a new heir thread.

 */

void _Thread_Clear_state(

  Thread_Control *the_thread,

  States_Control  state

);

/*

 *  _Thread_Set_state

 *

 *  DESCRIPTION:

 *

 *  This routine sets the indicated states for the_thread.  It performs

 *  any necessary scheduling operations including the selection of

 *  a new heir thread.

 *

 */

void _Thread_Set_state(

  Thread_Control *the_thread,

  States_Control  state

);

/*

 *  _Thread_Set_transient

 *

 *  DESCRIPTION:

 *

 *  This routine sets the TRANSIENT state for the_thread.  It performs

 *  any necessary scheduling operations including the selection of

 *  a new heir thread.

 */

void _Thread_Set_transient(

  Thread_Control *the_thread

);

/*

 *  _Thread_Reset_timeslice

 *

 *  DESCRIPTION:

 *

 *  This routine is invoked upon expiration of the currently

 *  executing thread's timeslice.  If no other thread's are ready

 *  at the priority of the currently executing thread, then the

 *  executing thread's timeslice is reset.  Otherwise, the

 *  currently executing thread is placed at the rear of the

 *  FIFO for this priority and a new heir is selected.

 */

void _Thread_Reset_timeslice( void );

/*

 *  _Thread_Tickle_timeslice

 *

 *  DESCRIPTION:

 *

 *  This routine is invoked as part of processing each clock tick.

 *  It is responsible for determining if the current thread allows

 *  timeslicing and, if so, when its timeslice expires.

 */

void _Thread_Tickle_timeslice( void );

/*

 *  _Thread_Yield_processor

 *

 *  DESCRIPTION:

 *

 *  This routine is invoked when a thread wishes to voluntarily

 *  transfer control of the processor to another thread of equal

 *  or greater priority.

 */

void _Thread_Yield_processor( void );

/*

 *  _Thread_Rotate_Ready_Queue

 *

 *  DESCRIPTION:

 *

 *  This routine is invoked to rotate the ready queue for the

 *  given priority.  It can be used to yeild the processor

 *  by rotating the executing threads ready queue.

 */

void _Thread_Rotate_Ready_Queue(

  Priority_Control  priority

);

/*

 *  _Thread_Load_environment

 *

 *  DESCRIPTION:

 *

 *  This routine initializes the context of the_thread to its

 *  appropriate starting state.

 */

void _Thread_Load_environment(

  Thread_Control *the_thread

);

/*

 *  _Thread_Handler

 *

 *  DESCRIPTION:

 *

 *  This routine is the wrapper function for all threads.  It is

 *  the starting point for all threads.  The user provided thread

 *  entry point is invoked by this routine.  Operations

 *  which must be performed immediately before and after the user's

 *  thread executes are found here.

 */

void _Thread_Handler( void );

/*

 *  _Thread_Delay_ended

 *

 *  DESCRIPTION:

 *

 *  This routine is invoked when a thread must be unblocked at the

 *  end of a time based delay (i.e. wake after or wake when).

 */

void _Thread_Delay_ended(

  Objects_Id  id,

  void       *ignored

);

/*

 *  _Thread_Change_priority

 *

 *  DESCRIPTION:

 *

 *  This routine changes the current priority of the_thread to

 *  new_priority.  It performs any necessary scheduling operations

 *  including the selection of a new heir thread.

 */

void _Thread_Change_priority (

  Thread_Control   *the_thread,

  Priority_Control  new_priority,

  boolean           prepend_it

);

/*

 *  _Thread_Set_priority

 *

 *  DESCRIPTION:

 *

 *  This routine updates the priority related fields in the_thread

 *  control block to indicate the current priority is now new_priority.

 */

void _Thread_Set_priority(

  Thread_Control   *the_thread,

  Priority_Control  new_priority

);

/*

 *  _Thread_Suspend

 *

 *  DESCRIPTION:

 *

 *  This routine updates the related suspend fields in the_thread

 *  control block to indicate the current nested level.

 */

void _Thread_Suspend(

  Thread_Control   *the_thread

);

/*

 *  _Thread_Resume

 *

 *  DESCRIPTION:

 *

 *  This routine updates the related suspend fields in the_thread

 *  control block to indicate the current nested level.  A force

 *  parameter of TRUE will force a resume and clear the suspend count.

 */

void _Thread_Resume(

  Thread_Control   *the_thread,

  boolean           force

);

/*

 *  _Thread_Evaluate_mode

 *

 *  DESCRIPTION:

 *

 *  This routine evaluates the current scheduling information for the

 *  system and determines if a context switch is required.  This

 *  is usually called after changing an execution mode such as preemptability

 *  for a thread.

 */

boolean _Thread_Evaluate_mode( void );

/*

 *  _Thread_Get

 *

 *  NOTE:  If we are not using static inlines, this must be a real

 *         subroutine call.

 */

#ifndef USE_INLINES

Thread_Control *_Thread_Get (

  Objects_Id           id,

  Objects_Locations   *location

);

#endif

/*

 *  _Thread_Idle_body

 *

 *  DESCRIPTION:

 *

 *  This routine is the body of the system idle thread.

 */

#if (CPU_PROVIDES_IDLE_THREAD_BODY == FALSE)

Thread _Thread_Idle_body(

  unsigned32 ignored

);

#endif

#ifndef __RTEMS_APPLICATION__

#include <rtems/score/thread.inl>

#endif

#if defined(RTEMS_MULTIPROCESSING)

#include <rtems/score/threadmp.h>

#endif

#ifdef __cplusplus

}

#endif

#endif

/* end of include file */