/**
* @file rtems/score/thread.h
*
* This include file contains all constants and structures associated
* with the thread control block.
*/
/*
* COPYRIGHT (c) 1989-2011.
* 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 _RTEMS_SCORE_THREAD_H
#define _RTEMS_SCORE_THREAD_H
/**
* @defgroup ScoreThread Thread Handler
*
* This handler encapsulates functionality related to the management of
* threads. This includes the creation, deletion, and scheduling of threads.
*
* The following variables are maintained as part of the per cpu data
* structure.
*
* + Idle thread pointer
* + Executing thread pointer
* + Heir thread pointer
*/
/**@{*/
#if defined(RTEMS_POSIX_API)
#define RTEMS_SCORE_THREAD_ENABLE_EXHAUST_TIMESLICE
#endif
#if defined(RTEMS_POSIX_API)
#define RTEMS_SCORE_THREAD_ENABLE_SCHEDULER_CALLOUT
#endif
#if defined(RTEMS_POSIX_API)
#define RTEMS_SCORE_THREAD_ENABLE_USER_PROVIDED_STACK_VIA_API
#endif
#if defined(RTEMS_SMP) || \
defined(RTEMS_HEAVY_STACK_DEBUG) || \
defined(RTEMS_HEAVY_MALLOC_DEBUG)
#define __THREAD_DO_NOT_INLINE_DISABLE_DISPATCH__
#endif
#if defined(RTEMS_SMP) || \
(CPU_INLINE_ENABLE_DISPATCH == FALSE) || \
(__RTEMS_DO_NOT_INLINE_THREAD_ENABLE_DISPATCH__ == 1)
#define __THREAD_DO_NOT_INLINE_ENABLE_DISPATCH__
#endif
#ifdef __cplusplus
extern "C" {
#endif
/*
* The user can define this at configure time and go back to ticks
* resolution.
*/
#ifndef __RTEMS_USE_TICKS_FOR_STATISTICS__
#include <rtems/score/timestamp.h>
typedef Timestamp_Control Thread_CPU_usage_t;
#else
typedef uint32_t Thread_CPU_usage_t;
#endif
#include <rtems/score/percpu.h>
#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/scheduler.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 uint32_t . :)
*/
typedef void *Thread;
/**
* @brief Type of the numeric argument of a thread entry function with at
* least one numeric argument.
*
* This numeric argument type designates an unsigned integer type with the
* property that any valid pointer to void can be converted to this type and
* then converted back to a pointer to void. The result will compare equal to
* the original pointer.
*/
typedef uintptr_t Thread_Entry_numeric_type;
/**
* 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,
#if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API)
THREAD_START_BOTH_POINTER_FIRST,
THREAD_START_BOTH_NUMERIC_FIRST
#endif
} Thread_Start_types;
/** This type corresponds to a very simple style thread entry point. */
typedef Thread ( *Thread_Entry )( void ); /* basic type */
/** This type corresponds to a thread entry point which takes a single
* unsigned thirty-two bit integer as an argument.
*/
typedef Thread ( *Thread_Entry_numeric )( Thread_Entry_numeric_type );
/** This type corresponds to a thread entry point which takes a single
* untyped pointer as an argument.
*/
typedef Thread ( *Thread_Entry_pointer )( void * );
/** This type corresponds to a thread entry point which takes a single
* untyped pointer and an unsigned thirty-two bit integer as arguments.
*/
typedef Thread ( *Thread_Entry_both_pointer_first )( void *, Thread_Entry_numeric_type );
/** This type corresponds to a thread entry point which takes a single
* unsigned thirty-two bit integer and an untyped pointer and an
* as arguments.
*/
typedef Thread ( *Thread_Entry_both_numeric_first )( Thread_Entry_numeric_type, 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,
#if defined(RTEMS_SCORE_THREAD_ENABLE_EXHAUST_TIMESLICE)
THREAD_CPU_BUDGET_ALGORITHM_EXHAUST_TIMESLICE,
#endif
#if defined(RTEMS_SCORE_THREAD_ENABLE_SCHEDULER_CALLOUT)
THREAD_CPU_BUDGET_ALGORITHM_CALLOUT
#endif
} Thread_CPU_budget_algorithms;
/** This defines thes the entry point for the thread specific timeslice
* budget management algorithm.
*/
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.
*/
typedef struct {
/** 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 *);
} rtems_task_variable_t;
/**
* The following structure contains the information which defines
* the starting state of a thread.
*/
typedef struct {
/** This field is the starting address for the thread. */
Thread_Entry entry_point;
/** This field indicates the how task is invoked. */
Thread_Start_types prototype;
/** This field is the pointer argument passed at thread start. */
void *pointer_argument;
/** This field is the numeric argument passed at thread start. */
Thread_Entry_numeric_type numeric_argument;
/*-------------- initial execution modes ----------------- */
/** This field indicates whether the thread was preemptible when
* it started.
*/
bool is_preemptible;
/** This field indicates the CPU budget algorith. */
Thread_CPU_budget_algorithms budget_algorithm;
/** This field is the routine to invoke when the CPU allotment is
* consumed.
*/
Thread_CPU_budget_algorithm_callout budget_callout;
/** This field is the initial ISR disable level of this thread. */
uint32_t isr_level;
/** This field is the initial priority. */
Priority_Control initial_priority;
#if defined(RTEMS_SCORE_THREAD_ENABLE_USER_PROVIDED_STACK_VIA_API)
/** This field indicates whether the SuperCore allocated the stack. */
bool core_allocated_stack;
#endif
/** This field is the stack information. */
Stack_Control Initial_stack;
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
/** This field is the initial FP context area address. */
Context_Control_fp *fp_context;
#endif
/** This field is the initial stack area address. */
void *stack;
} 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 Union type to hold a pointer to an immutable or a mutable object.
*
* The main purpose is to enable passing of pointers to read-only send buffers
* in the message passing subsystem. This approach is somewhat fragile since
* it prevents the compiler to check if the operations on objects are valid
* with respect to the constant qualifier. An alternative would be to add a
* third pointer argument for immutable objects, but this would increase the
* structure size.
*/
typedef union {
void *mutable_object;
const void *immutable_object;
} Thread_Wait_information_Object_argument_type;
/** @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 for a pointer to a user return argument. */
void *return_argument;
/** This field is for a pointer to a second user return argument. */
Thread_Wait_information_Object_argument_type
return_argument_second;
/** 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 {
/** This field is the object management structure for each proxy. */
Objects_Control Object;
/** This field is the current execution state of this proxy. */
States_Control current_state;
/** This field is the current priority state of this proxy. */
Priority_Control current_priority;
/** This field is the base priority of this proxy. */
Priority_Control real_priority;
/** This field is the number of mutexes currently held by this proxy. */
uint32_t resource_count;
/** This field is the blocking information for this proxy. */
Thread_Wait_information Wait;
/** This field is the Watchdog used to manage proxy delays and timeouts. */
Watchdog_Control Timer;
#if defined(RTEMS_MULTIPROCESSING)
/** This field is the received response packet in an MP system. */
MP_packet_Prefix *receive_packet;
#endif
/****************** end of common block ********************/
/** This field is used to manage the set of proxies in the system. */
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 {
/** This value is for the Classic RTEMS API. */
THREAD_API_RTEMS,
/** This value is for the POSIX API. */
THREAD_API_POSIX
} Thread_APIs;
/** This macro defines the first API which has threads. */
#define THREAD_API_FIRST THREAD_API_RTEMS
/** This macro defines the last API which has threads. */
#define THREAD_API_LAST THREAD_API_POSIX
/**
* This structure defines the Thread Control Block (TCB).
*/
struct Thread_Control_struct {
/** This field is the object management structure for each thread. */
Objects_Control Object;
/** This field is the current execution state of this thread. */
States_Control current_state;
/** This field is the current priority state of this thread. */
Priority_Control current_priority;
/** This field is the base priority of this thread. */
Priority_Control real_priority;
/** This field is the number of mutexes currently held by this thread. */
uint32_t resource_count;
/** This field is the blocking information for this thread. */
Thread_Wait_information Wait;
/** This field is the Watchdog used to manage thread delays and timeouts. */
Watchdog_Control Timer;
#if defined(RTEMS_MULTIPROCESSING)
/** This field is the received response packet in an MP system. */
MP_packet_Prefix *receive_packet;
#endif
#ifdef __RTEMS_STRICT_ORDER_MUTEX__
/** This field is the head of queue of priority inheritance mutex
* held by the thread.
*/
Chain_Control lock_mutex;
#endif
/*================= end of common block =================*/
/** This field is the number of nested suspend calls. */
uint32_t suspend_count;
#if defined(RTEMS_MULTIPROCESSING)
/** This field is true if the thread is offered globally */
bool is_global;
#endif
/** This field is true if the thread is preemptible. */
bool is_preemptible;
#if __RTEMS_ADA__
/** This field is the GNAT self context pointer. */
void *rtems_ada_self;
#endif
/** This field is the length of the time quantum that this thread is
* allowed to consume. The algorithm used to manage limits on CPU usage
* is specified by budget_algorithm.
*/
uint32_t cpu_time_budget;
/** This field is the algorithm used to manage this thread's time
* quantum. The algorithm may be specified as none which case,
* no limit is in place.
*/
Thread_CPU_budget_algorithms budget_algorithm;
/** This field is the method invoked with the budgeted time is consumed. */
Thread_CPU_budget_algorithm_callout budget_callout;
/** This field is the amount of CPU time consumed by this thread
* since it was created.
*/
Thread_CPU_usage_t cpu_time_used;
/** This pointer holds per-thread data for the scheduler and ready queue. */
void *scheduler_info;
/** This field contains information about the starting state of
* this thread.
*/
Thread_Start_information Start;
/** This field contains the context of this thread. */
Context_Control Registers;
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
/** This field points to the floating point context for this thread.
* If NULL, the thread is integer only.
*/
Context_Control_fp *fp_context;
#endif
/** This field points to the newlib reentrancy structure for this thread. */
struct _reent *libc_reent;
/** This array contains the API extension area pointers. */
void *API_Extensions[ THREAD_API_LAST + 1 ];
/** This field points to the user extension pointers. */
void **extensions;
/** This field points to the set of per task variables. */
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 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;
/**
* 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 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;
#ifndef __RTEMS_USE_TICKS_FOR_STATISTICS__
/**
* This contains the time since boot when the last context switch occurred.
* By placing it in the BSS, it will automatically be zeroed out at
* system initialization and does not need to be known outside this
* file.
*/
SCORE_EXTERN Timestamp_Control _Thread_Time_of_last_context_switch;
#endif
/**
* This routine performs the initialization necessary for this handler.
*/
void _Thread_Handler_initialization(void);
/**
* 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
*/
size_t _Thread_Stack_Allocate(
Thread_Control *the_thread,
size_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.
*/
bool _Thread_Initialize(
Objects_Information *information,
Thread_Control *the_thread,
void *stack_area,
size_t stack_size,
bool is_fp,
Priority_Control priority,
bool 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.
*/
bool _Thread_Start(
Thread_Control *the_thread,
Thread_Start_types the_prototype,
void *entry_point,
void *pointer_argument,
Thread_Entry_numeric_type 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
*/
bool _Thread_Restart(
Thread_Control *the_thread,
void *pointer_argument,
Thread_Entry_numeric_type 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,
Thread_Entry_numeric_type 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 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 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,
bool 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.
*/
#define _Thread_Suspend( _the_thread ) \
_Thread_Set_state( _the_thread, STATES_SUSPENDED )
/**
* 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.
*/
#define _Thread_Resume( _the_thread ) \
_Thread_Clear_state( _the_thread, STATES_SUSPENDED )
#if (CPU_PROVIDES_IDLE_THREAD_BODY == FALSE)
/**
* This routine is the body of the system idle thread.
*
* NOTE: This routine is actually instantiated by confdefs.h when needed.
*/
void *_Thread_Idle_body(
uintptr_t ignored
);
#endif
/** This defines the type for a method which operates on a single thread.
*/
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
);
/**
* This function maps thread IDs to thread control
* blocks. If ID corresponds to a local thread, then it
* returns the_thread control pointer which maps to ID
* and location is set to OBJECTS_LOCAL. If the thread ID is
* global and resides on a remote node, then location is set
* to OBJECTS_REMOTE, and the_thread is undefined.
* Otherwise, location is set to OBJECTS_ERROR and
* the_thread is undefined.
*
* @note The performance of many RTEMS services depends upon
* the quick execution of the "good object" path in this
* routine. If there is a possibility of saving a few
* cycles off the execution time, this routine is worth
* further optimization attention.
*/
Thread_Control *_Thread_Get (
Objects_Id id,
Objects_Locations *location
);
/**
* @brief Cancel a blocking operation due to ISR
*
* This method is used to cancel a blocking operation that was
* satisfied from an ISR while the thread executing was in the
* process of blocking.
*
* @param[in] sync_state is the synchronization state
* @param[in] the_thread is the thread whose blocking is canceled
* @param[in] level is the previous ISR disable level
*
* @note This is a rare routine in RTEMS. It is called with
* interrupts disabled and only when an ISR completed
* a blocking condition in process.
*/
void _Thread_blocking_operation_Cancel(
Thread_blocking_operation_States sync_state,
Thread_Control *the_thread,
ISR_Level level
);
#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 */
