static void _Thread_Free( Thread_Control *the_thread )
{
_User_extensions_Thread_delete( the_thread );
/*
* Free the per-thread scheduling information.
*/
_Scheduler_Node_destroy( _Scheduler_Get( the_thread ), the_thread );
/*
* The thread might have been FP. So deal with that.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
if ( _Thread_Is_allocated_fp( the_thread ) )
_Thread_Deallocate_fp();
#endif
_Workspace_Free( the_thread->Start.fp_context );
#endif
/*
* Free the rest of the memory associated with this task
* and set the associated pointers to NULL for safety.
*/
_Thread_Stack_Free( the_thread );
_Workspace_Free( the_thread->Start.tls_area );
_Objects_Free(
_Objects_Get_information_id( the_thread->Object.id ),
&the_thread->Object
);
}
static void _Thread_Free( Thread_Control *the_thread )
{
Thread_Information *information = (Thread_Information *)
_Objects_Get_information_id( the_thread->Object.id );
_User_extensions_Thread_delete( the_thread );
_User_extensions_Destroy_iterators( the_thread );
_ISR_lock_Destroy( &the_thread->Keys.Lock );
_Scheduler_Node_destroy(
_Thread_Scheduler_get_home( the_thread ),
_Thread_Scheduler_get_home_node( the_thread )
);
_ISR_lock_Destroy( &the_thread->Timer.Lock );
/*
* The thread might have been FP. So deal with that.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
if ( _Thread_Is_allocated_fp( the_thread ) )
_Thread_Deallocate_fp();
#endif
_Workspace_Free( the_thread->Start.fp_context );
#endif
_Freechain_Put(
&information->Free_thread_queue_heads,
the_thread->Wait.spare_heads
);
/*
* Free the rest of the memory associated with this task
* and set the associated pointers to NULL for safety.
*/
_Thread_Stack_Free( the_thread );
_Workspace_Free( the_thread->Start.tls_area );
#if defined(RTEMS_SMP)
_ISR_lock_Destroy( &the_thread->Scheduler.Lock );
_ISR_lock_Destroy( &the_thread->Wait.Lock.Default );
_SMP_lock_Stats_destroy( &the_thread->Potpourri_stats );
#endif
_Thread_queue_Destroy( &the_thread->Join_queue );
_Objects_Free( &information->Objects, &the_thread->Object );
}
void _Thread_Handler( void )
{
ISR_Level level;
Thread_Control *executing;
#if defined(EXECUTE_GLOBAL_CONSTRUCTORS)
static char doneConstructors;
char doneCons;
#endif
executing = _Thread_Executing;
/*
* Some CPUs need to tinker with the call frame or registers when the
* thread actually begins to execute for the first time. This is a
* hook point where the port gets a shot at doing whatever it requires.
*/
_Context_Initialization_at_thread_begin();
/*
* have to put level into a register for those cpu's that use
* inline asm here
*/
level = executing->Start.isr_level;
_ISR_Set_level(level);
#if defined(EXECUTE_GLOBAL_CONSTRUCTORS)
doneCons = doneConstructors;
doneConstructors = 1;
#endif
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
if ( (executing->fp_context != NULL) &&
!_Thread_Is_allocated_fp( executing ) ) {
if ( _Thread_Allocated_fp != NULL )
_Context_Save_fp( &_Thread_Allocated_fp->fp_context );
_Thread_Allocated_fp = executing;
}
#endif
#endif
/*
* Take care that 'begin' extensions get to complete before
* 'switch' extensions can run. This means must keep dispatch
* disabled until all 'begin' extensions complete.
*/
_User_extensions_Thread_begin( executing );
/*
* At this point, the dispatch disable level BETTER be 1.
*/
_Thread_Enable_dispatch();
#if defined(EXECUTE_GLOBAL_CONSTRUCTORS)
/*
* _init could be a weak symbol and we SHOULD test it but it isn't
* in any configuration I know of and it generates a warning on every
* RTEMS target configuration. --joel (12 May 2007)
*/
if (!doneCons) /* && (volatile void *)_init) */ {
INIT_NAME ();
}
#endif
if ( executing->Start.prototype == THREAD_START_NUMERIC ) {
executing->Wait.return_argument =
(*(Thread_Entry_numeric) executing->Start.entry_point)(
executing->Start.numeric_argument
);
}
#if defined(RTEMS_POSIX_API)
else if ( executing->Start.prototype == THREAD_START_POINTER ) {
executing->Wait.return_argument =
(*(Thread_Entry_pointer) executing->Start.entry_point)(
executing->Start.pointer_argument
);
}
#endif
#if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API)
else if ( executing->Start.prototype == THREAD_START_BOTH_POINTER_FIRST ) {
executing->Wait.return_argument =
(*(Thread_Entry_both_pointer_first) executing->Start.entry_point)(
executing->Start.pointer_argument,
executing->Start.numeric_argument
);
}
else if ( executing->Start.prototype == THREAD_START_BOTH_NUMERIC_FIRST ) {
executing->Wait.return_argument =
(*(Thread_Entry_both_numeric_first) executing->Start.entry_point)(
executing->Start.numeric_argument,
executing->Start.pointer_argument
);
}
#endif
/*
* In the switch above, the return code from the user thread body
* was placed in return_argument. This assumed that if it returned
* anything (which is not supporting in all APIs), then it would be
* able to fit in a (void *).
*/
_User_extensions_Thread_exitted( executing );
_Internal_error_Occurred(
INTERNAL_ERROR_CORE,
true,
INTERNAL_ERROR_THREAD_EXITTED
);
}
void _Thread_Handler( void )
{
Thread_Control *executing = _Thread_Executing;
ISR_Level level;
/*
* Some CPUs need to tinker with the call frame or registers when the
* thread actually begins to execute for the first time. This is a
* hook point where the port gets a shot at doing whatever it requires.
*/
_Context_Initialization_at_thread_begin();
#if !defined(RTEMS_SMP)
/*
* have to put level into a register for those cpu's that use
* inline asm here
*/
level = executing->Start.isr_level;
_ISR_Set_level( level );
#endif
/*
* Initialize the floating point context because we do not come
* through _Thread_Dispatch on our first invocation. So the normal
* code path for performing the FP context switch is not hit.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
if ( (executing->fp_context != NULL) &&
!_Thread_Is_allocated_fp( executing ) ) {
if ( _Thread_Allocated_fp != NULL )
_Context_Save_fp( &_Thread_Allocated_fp->fp_context );
_Thread_Allocated_fp = executing;
}
#endif
#endif
/*
* Take care that 'begin' extensions get to complete before
* 'switch' extensions can run. This means must keep dispatch
* disabled until all 'begin' extensions complete.
*/
_User_extensions_Thread_begin( executing );
/*
* At this point, the dispatch disable level BETTER be 1.
*/
#if defined(RTEMS_SMP)
{
/*
* On SMP we enter _Thread_Handler() with interrupts disabled and
* _Thread_Dispatch() obtained the per-CPU lock for us. We have to
* release it here and set the desired interrupt level of the thread.
*/
Per_CPU_Control *cpu_self = _Per_CPU_Get();
_Assert( cpu_self->thread_dispatch_disable_level == 1 );
_Assert( _ISR_Get_level() != 0 );
_Thread_Debug_set_real_processor( executing, cpu_self );
cpu_self->thread_dispatch_disable_level = 0;
_Profiling_Thread_dispatch_enable( cpu_self, 0 );
level = executing->Start.isr_level;
_ISR_Set_level( level);
/*
* The thread dispatch level changed from one to zero. Make sure we lose
* no thread dispatch necessary update.
*/
_Thread_Dispatch();
}
#else
_Thread_Enable_dispatch();
#endif
/*
* RTEMS supports multiple APIs and each API can define a different
* thread/task prototype. The following code supports invoking the
* user thread entry point using the prototype expected.
*/
if ( executing->Start.prototype == THREAD_START_NUMERIC ) {
executing->Wait.return_argument =
(*(Thread_Entry_numeric) executing->Start.entry_point)(
executing->Start.numeric_argument
);
}
#if defined(RTEMS_POSIX_API)
else if ( executing->Start.prototype == THREAD_START_POINTER ) {
executing->Wait.return_argument =
(*(Thread_Entry_pointer) executing->Start.entry_point)(
executing->Start.pointer_argument
);
}
#endif
#if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API)
else if ( executing->Start.prototype == THREAD_START_BOTH_POINTER_FIRST ) {
executing->Wait.return_argument =
(*(Thread_Entry_both_pointer_first) executing->Start.entry_point)(
executing->Start.pointer_argument,
executing->Start.numeric_argument
);
}
else if ( executing->Start.prototype == THREAD_START_BOTH_NUMERIC_FIRST ) {
executing->Wait.return_argument =
(*(Thread_Entry_both_numeric_first) executing->Start.entry_point)(
executing->Start.numeric_argument,
executing->Start.pointer_argument
);
}
#endif
/*
* In the switch above, the return code from the user thread body
* was placed in return_argument. This assumed that if it returned
* anything (which is not supporting in all APIs), then it would be
* able to fit in a (void *).
*/
_User_extensions_Thread_exitted( executing );
_Terminate(
INTERNAL_ERROR_CORE,
true,
INTERNAL_ERROR_THREAD_EXITTED
);
}
void _Thread_Close(
Objects_Information *information,
Thread_Control *the_thread
)
{
/*
* Now we are in a dispatching critical section again and we
* can take the thread OUT of the published set. It is invalid
* to use this thread's Id after this call. This will prevent
* any other task from attempting to initiate a call on this task.
*/
_Objects_Invalidate_Id( information, &the_thread->Object );
/*
* We assume the Allocator Mutex is locked when we get here.
* This provides sufficient protection to let the user extensions
* run but as soon as we get back, we will make the thread
* disappear and set a transient state on it. So we temporarily
* unnest dispatching.
*/
_Thread_Unnest_dispatch();
_User_extensions_Thread_delete( the_thread );
_Thread_Disable_dispatch();
/*
* Now we are in a dispatching critical section again and we
* can take the thread OUT of the published set. It is invalid
* to use this thread's Id OR name after this call.
*/
_Objects_Close( information, &the_thread->Object );
/*
* By setting the dormant state, the thread will not be considered
* for scheduling when we remove any blocking states.
*/
_Thread_Set_state( the_thread, STATES_DORMANT );
if ( !_Thread_queue_Extract_with_proxy( the_thread ) ) {
if ( _Watchdog_Is_active( &the_thread->Timer ) )
(void) _Watchdog_Remove( &the_thread->Timer );
}
/*
* Free the per-thread scheduling information.
*/
_Scheduler_Free( the_thread );
/*
* The thread might have been FP. So deal with that.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
if ( _Thread_Is_allocated_fp( the_thread ) )
_Thread_Deallocate_fp();
#endif
the_thread->fp_context = NULL;
_Workspace_Free( the_thread->Start.fp_context );
#endif
/*
* Free the rest of the memory associated with this task
* and set the associated pointers to NULL for safety.
*/
_Thread_Stack_Free( the_thread );
the_thread->Start.stack = NULL;
_Workspace_Free( the_thread->extensions );
the_thread->extensions = NULL;
_Workspace_Free( the_thread->Start.tls_area );
}
void _Thread_Dispatch( void )
{
Per_CPU_Control *cpu_self;
Thread_Control *executing;
ISR_Level level;
#if defined( RTEMS_SMP )
/*
* On SMP the complete context switch must be atomic with respect to one
* processor. See also _Thread_Handler() since _Context_switch() may branch
* to this function.
*/
_ISR_Disable_without_giant( level );
#endif
cpu_self = _Per_CPU_Get();
_Assert( cpu_self->thread_dispatch_disable_level == 0 );
_Profiling_Thread_dispatch_disable( cpu_self, 0 );
cpu_self->thread_dispatch_disable_level = 1;
/*
* Now determine if we need to perform a dispatch on the current CPU.
*/
executing = cpu_self->executing;
#if !defined( RTEMS_SMP )
_ISR_Disable( level );
#endif
#if defined( RTEMS_SMP )
if ( cpu_self->dispatch_necessary ) {
#else
while ( cpu_self->dispatch_necessary ) {
#endif
Thread_Control *heir = _Thread_Get_heir_and_make_it_executing( cpu_self );
/*
* When the heir and executing are the same, then we are being
* requested to do the post switch dispatching. This is normally
* done to dispatch signals.
*/
if ( heir == executing )
goto post_switch;
/*
* Since heir and executing are not the same, we need to do a real
* context switch.
*/
#if __RTEMS_ADA__
executing->rtems_ada_self = rtems_ada_self;
rtems_ada_self = heir->rtems_ada_self;
#endif
if ( heir->budget_algorithm == THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE )
heir->cpu_time_budget = rtems_configuration_get_ticks_per_timeslice();
#if !defined( RTEMS_SMP )
_ISR_Enable( level );
#endif
#ifndef __RTEMS_USE_TICKS_FOR_STATISTICS__
_Thread_Update_cpu_time_used(
executing,
&cpu_self->time_of_last_context_switch
);
#else
{
_TOD_Get_uptime( &cpu_self->time_of_last_context_switch );
heir->cpu_time_used++;
}
#endif
#if !defined(__DYNAMIC_REENT__)
/*
* Switch libc's task specific data.
*/
if ( _Thread_libc_reent ) {
executing->libc_reent = *_Thread_libc_reent;
*_Thread_libc_reent = heir->libc_reent;
}
#endif
_User_extensions_Thread_switch( executing, heir );
/*
* If the CPU has hardware floating point, then we must address saving
* and restoring it as part of the context switch.
*
* The second conditional compilation section selects the algorithm used
* to context switch between floating point tasks. The deferred algorithm
* can be significantly better in a system with few floating point tasks
* because it reduces the total number of save and restore FP context
* operations. However, this algorithm can not be used on all CPUs due
* to unpredictable use of FP registers by some compilers for integer
* operations.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH != TRUE )
if ( executing->fp_context != NULL )
_Context_Save_fp( &executing->fp_context );
#endif
#endif
_Context_Switch( &executing->Registers, &heir->Registers );
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
if ( (executing->fp_context != NULL) &&
!_Thread_Is_allocated_fp( executing ) ) {
if ( _Thread_Allocated_fp != NULL )
_Context_Save_fp( &_Thread_Allocated_fp->fp_context );
_Context_Restore_fp( &executing->fp_context );
_Thread_Allocated_fp = executing;
}
#else
if ( executing->fp_context != NULL )
_Context_Restore_fp( &executing->fp_context );
#endif
#endif
/*
* We have to obtain this value again after the context switch since the
* heir thread may have migrated from another processor. Values from the
* stack or non-volatile registers reflect the old execution environment.
*/
cpu_self = _Per_CPU_Get();
_Thread_Debug_set_real_processor( executing, cpu_self );
#if !defined( RTEMS_SMP )
_ISR_Disable( level );
#endif
}
post_switch:
_Assert( cpu_self->thread_dispatch_disable_level == 1 );
cpu_self->thread_dispatch_disable_level = 0;
_Profiling_Thread_dispatch_enable( cpu_self, 0 );
_ISR_Enable_without_giant( level );
_Thread_Run_post_switch_actions( executing );
}
void _Thread_Dispatch( void )
{
Thread_Control *executing;
Thread_Control *heir;
ISR_Level level;
#if defined(RTEMS_SMP)
/*
* WARNING: The SMP sequence has severe defects regarding the real-time
* performance.
*
* Consider the following scenario. We have three tasks L (lowest
* priority), M (middle priority), and H (highest priority). Now let a
* thread dispatch from M to L happen. An interrupt occurs in
* _Thread_Dispatch() here:
*
* void _Thread_Dispatch( void )
* {
* [...]
*
* post_switch:
*
* _ISR_Enable( level );
*
* <-- INTERRUPT
* <-- AFTER INTERRUPT
*
* _Thread_Unnest_dispatch();
*
* _API_extensions_Run_post_switch();
* }
*
* The interrupt event makes task H ready. The interrupt code will see
* _Thread_Dispatch_disable_level > 0 and thus doesn't perform a
* _Thread_Dispatch(). Now we return to position "AFTER INTERRUPT". This
* means task L executes now although task H is ready! Task H will execute
* once someone calls _Thread_Dispatch().
*/
_Thread_Disable_dispatch();
/*
* If necessary, send dispatch request to other cores.
*/
_SMP_Request_other_cores_to_dispatch();
#endif
/*
* Now determine if we need to perform a dispatch on the current CPU.
*/
executing = _Thread_Executing;
_ISR_Disable( level );
while ( _Thread_Dispatch_necessary == true ) {
heir = _Thread_Heir;
#ifndef RTEMS_SMP
_Thread_Dispatch_set_disable_level( 1 );
#endif
_Thread_Dispatch_necessary = false;
_Thread_Executing = heir;
/*
* When the heir and executing are the same, then we are being
* requested to do the post switch dispatching. This is normally
* done to dispatch signals.
*/
if ( heir == executing )
goto post_switch;
/*
* Since heir and executing are not the same, we need to do a real
* context switch.
*/
#if __RTEMS_ADA__
executing->rtems_ada_self = rtems_ada_self;
rtems_ada_self = heir->rtems_ada_self;
#endif
if ( heir->budget_algorithm == THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE )
heir->cpu_time_budget = _Thread_Ticks_per_timeslice;
_ISR_Enable( level );
#ifndef __RTEMS_USE_TICKS_FOR_STATISTICS__
{
Timestamp_Control uptime, ran;
_TOD_Get_uptime( &uptime );
_Timestamp_Subtract(
&_Thread_Time_of_last_context_switch,
&uptime,
&ran
);
_Timestamp_Add_to( &executing->cpu_time_used, &ran );
_Thread_Time_of_last_context_switch = uptime;
}
#else
{
_TOD_Get_uptime( &_Thread_Time_of_last_context_switch );
heir->cpu_time_used++;
}
#endif
/*
* Switch libc's task specific data.
*/
if ( _Thread_libc_reent ) {
executing->libc_reent = *_Thread_libc_reent;
*_Thread_libc_reent = heir->libc_reent;
}
_User_extensions_Thread_switch( executing, heir );
/*
* If the CPU has hardware floating point, then we must address saving
* and restoring it as part of the context switch.
*
* The second conditional compilation section selects the algorithm used
* to context switch between floating point tasks. The deferred algorithm
* can be significantly better in a system with few floating point tasks
* because it reduces the total number of save and restore FP context
* operations. However, this algorithm can not be used on all CPUs due
* to unpredictable use of FP registers by some compilers for integer
* operations.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH != TRUE )
if ( executing->fp_context != NULL )
_Context_Save_fp( &executing->fp_context );
#endif
#endif
_Context_Switch( &executing->Registers, &heir->Registers );
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
if ( (executing->fp_context != NULL) &&
!_Thread_Is_allocated_fp( executing ) ) {
if ( _Thread_Allocated_fp != NULL )
_Context_Save_fp( &_Thread_Allocated_fp->fp_context );
_Context_Restore_fp( &executing->fp_context );
_Thread_Allocated_fp = executing;
}
#else
if ( executing->fp_context != NULL )
_Context_Restore_fp( &executing->fp_context );
#endif
#endif
executing = _Thread_Executing;
_ISR_Disable( level );
}
post_switch:
#ifndef RTEMS_SMP
_Thread_Dispatch_set_disable_level( 0 );
#endif
_ISR_Enable( level );
#ifdef RTEMS_SMP
_Thread_Unnest_dispatch();
#endif
_API_extensions_Run_post_switch( executing );
}
