/** * @file thread.h * * This include file contains all constants and structures associated * with the thread control block. */ /* * COPYRIGHT (c) 1989-2004. * 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.rtems.com/license/LICENSE. * * $Id$ */ #ifndef __THREAD_h #define __THREAD_h /** * @defgroup ScoreThread Thread Handler * * This group contains functionality which XXX */ /**@{*/ #ifdef __cplusplus extern "C" { #endif #include #include #if defined(RTEMS_MULTIPROCESSING) #include #endif #include #include #include #include #include #include #include /** * 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 uint32_t . :) */ 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 uint32_t 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 )( uint32_t ); /** */ typedef Thread ( *Thread_Entry_pointer )( void * ); /** */ typedef Thread ( *Thread_Entry_both_pointer_first )( void *, uint32_t ); /** */ typedef Thread ( *Thread_Entry_both_numeric_first )( uint32_t , 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 * ); /** @brief Per Task Variable Manager Structure Forward Reference * * Forward reference to the per task variable structure. */ struct rtems_task_variable_tt; /** @brief Per Task Variable Manager Structure * * This is the internal structure used to manager per Task Variables. */ struct rtems_task_variable_tt { /** This field points to the next per task variable for this task. */ struct rtems_task_variable_tt *next; /** This field points to the physical memory location of this per * task variable. */ void **ptr; /** This field is to the global value for this per task variable. */ void *gval; /** This field is to this thread's value for this per task variable. */ void *tval; /** This field points to the destructor for this per task variable. */ 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 */ uint32_t numeric_argument; /* numeric argument */ /* initial execution modes */ boolean is_preemptible; Thread_CPU_budget_algorithms budget_algorithm; Thread_CPU_budget_algorithm_callout budget_callout; uint32_t isr_level; Priority_Control initial_priority; /* initial priority */ boolean core_allocated_stack; Stack_Control Initial_stack; /* stack information */ #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE ) void *fp_context; /* initial FP context area address */ #endif 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 /** @brief Thread Blocking Management Information * * This contains the information required to manage a thread while it is * blocked and to return information to it. */ typedef struct { /** This field is the Id of the object this thread is waiting upon. */ Objects_Id id; /** This field is used to return an integer while when blocked. */ uint32_t count; /** This field is the first pointer to a user return argument. */ void *return_argument; /** This field is the second pointer to a user return argument. */ void *return_argument_1; /** This field contains any options in effect on this blocking operation. */ uint32_t option; /** This field will contain the return status from a blocking operation. * * @note The following assumes that all API return codes can be * treated as an uint32_t. */ uint32_t return_code; /** This field is the chain header for the second through Nth tasks * of the same priority blocked waiting on the same object. */ Chain_Control Block2n; /** This field points to the thread queue on which this thread is blocked. */ Thread_queue_Control *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; uint32_t 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; uint32_t resource_count; Thread_Wait_information Wait; Watchdog_Control Timer; #if defined(RTEMS_MULTIPROCESSING) MP_packet_Prefix *receive_packet; #endif /****************** end of common block ********************/ uint32_t suspend_count; boolean is_global; boolean do_post_task_switch_extension; boolean is_preemptible; void *rtems_ada_self; uint32_t cpu_time_budget; Thread_CPU_budget_algorithms budget_algorithm; Thread_CPU_budget_algorithm_callout budget_callout; uint32_t ticks_executed; Chain_Control *ready; Priority_Information Priority_map; Thread_Start_information Start; Context_Control Registers; #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE ) void *fp_context; #endif struct _reent *libc_reent; 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 uint32_t _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 uint32_t _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 uint32_t _Thread_Maximum_extensions; /** * The following is used to manage the length of a timeslice quantum. */ SCORE_EXTERN uint32_t _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. */ #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE ) SCORE_EXTERN Thread_Control *_Thread_Allocated_fp; #endif /** * The C library re-enter-rant global pointer. Some C library implementations * such as newlib have a single global pointer that changed during a context * switch. The pointer points to that global pointer. The Thread control block * holds a pointer to the task specific data. */ SCORE_EXTERN struct _reent **_Thread_libc_reent; /** * This routine performs the initialization necessary for this handler. */ void _Thread_Handler_initialization ( uint32_t ticks_per_timeslice, uint32_t maximum_extensions, uint32_t maximum_proxies ); /** * This routine creates the idle thread. * * @warning No thread should be created before this one. */ void _Thread_Create_idle( void ); /** * 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 ); /** * 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 ); /** * 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 */ uint32_t _Thread_Stack_Allocate( Thread_Control *the_thread, uint32_t stack_size ); /** * Deallocate the Thread's stack. */ void _Thread_Stack_Free( Thread_Control *the_thread ); /** * 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. * * @note If stack_area is NULL, it is allocated from the workspace. * * @note 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, uint32_t stack_size, boolean is_fp, Priority_Control priority, boolean is_preemptible, Thread_CPU_budget_algorithms budget_algorithm, Thread_CPU_budget_algorithm_callout budget_callout, uint32_t isr_level, Objects_Name name ); /** * 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, uint32_t numeric_argument ); /** * 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. * * TODO: multiple task arg profiles */ boolean _Thread_Restart( Thread_Control *the_thread, void *pointer_argument, uint32_t numeric_argument ); /** * This routine resets a thread to its initial state but does * not restart it. */ void _Thread_Reset( Thread_Control *the_thread, void *pointer_argument, uint32_t numeric_argument ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * This routine initializes the context of the_thread to its * appropriate starting state. */ void _Thread_Load_environment( Thread_Control *the_thread ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); /** * 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 ); #ifndef RTEMS_INLINES /** * @note If we are not using static inlines, this must be a real * subroutine call. */ Thread_Control *_Thread_Get ( Objects_Id id, Objects_Locations *location ); #endif #if (CPU_PROVIDES_IDLE_THREAD_BODY == FALSE) /** * This routine is the body of the system idle thread. */ Thread _Thread_Idle_body( uint32_t ignored ); #endif /** */ typedef void (*rtems_per_thread_routine)( Thread_Control * ); /** * This routine iterates over all threads regardless of API and * invokes the specified routine. */ void rtems_iterate_over_all_threads( rtems_per_thread_routine routine ); #ifndef __RTEMS_APPLICATION__ #include #endif #if defined(RTEMS_MULTIPROCESSING) #include #endif #ifdef __cplusplus } #endif /**@}*/ #endif /* end of include file */