rtems_task Floating_point_task_1(
rtems_task_argument argument
)
{
Scheduler_priority_Context *scheduler_context =
_Scheduler_priority_Get_context( _Scheduler_Get( _Thread_Get_executing() ) );
Thread_Control *executing;
FP_DECLARE;
context_switch_restore_1st_fp_time = benchmark_timer_read();
executing = _Thread_Get_executing();
set_thread_executing(
(Thread_Control *) _Chain_First(&scheduler_context->Ready[FP2_PRIORITY])
);
/* do not force context switch */
set_thread_dispatch_necessary( false );
_Thread_Dispatch_disable();
benchmark_timer_initialize();
#if (CPU_HARDWARE_FP == 1) || (CPU_SOFTWARE_FP == 1)
_Context_Save_fp( &executing->fp_context );
_Context_Restore_fp( &_Thread_Get_executing()->fp_context );
#endif
_Context_Switch(
&executing->Registers,
&_Thread_Get_executing()->Registers
);
/* switch to Floating_point_task_2 */
context_switch_save_idle_restore_initted_time = benchmark_timer_read();
FP_LOAD( 1.0 );
executing = _Thread_Get_executing();
set_thread_executing(
(Thread_Control *) _Chain_First(&scheduler_context->Ready[FP2_PRIORITY])
);
benchmark_timer_initialize();
#if (CPU_HARDWARE_FP == 1) || (CPU_SOFTWARE_FP == 1)
_Context_Save_fp( &executing->fp_context );
_Context_Restore_fp( &_Thread_Get_executing()->fp_context );
#endif
_Context_Switch(
&executing->Registers,
&_Thread_Get_executing()->Registers
);
/* switch to Floating_point_task_2 */
}
rtems_task Floating_point_task_1(
rtems_task_argument argument
)
{
Chain_Control *ready_queues;
Thread_Control *executing;
FP_DECLARE;
context_switch_restore_1st_fp_time = benchmark_timer_read();
executing = _Thread_Executing;
ready_queues = (Chain_Control *) _Scheduler.information;
_Thread_Executing =
(Thread_Control *) _Chain_First(&ready_queues[FP2_PRIORITY]);
/* do not force context switch */
_Thread_Dispatch_necessary = false;
_Thread_Disable_dispatch();
benchmark_timer_initialize();
#if (CPU_HARDWARE_FP == 1) || (CPU_SOFTWARE_FP == 1)
_Context_Save_fp( &executing->fp_context );
_Context_Restore_fp( &_Thread_Executing->fp_context );
#endif
_Context_Switch( &executing->Registers, &_Thread_Executing->Registers );
/* switch to Floating_point_task_2 */
context_switch_save_idle_restore_initted_time = benchmark_timer_read();
FP_LOAD( 1.0 );
executing = _Thread_Executing;
ready_queues = (Chain_Control *) _Scheduler.information;
_Thread_Executing =
(Thread_Control *) _Chain_First(&ready_queues[FP2_PRIORITY]);
/* do not force context switch */
_Thread_Dispatch_necessary = false;
_Thread_Disable_dispatch();
benchmark_timer_initialize();
#if (CPU_HARDWARE_FP == 1) || (CPU_SOFTWARE_FP == 1)
_Context_Save_fp( &executing->fp_context );
_Context_Restore_fp( &_Thread_Executing->fp_context );
#endif
_Context_Switch( &executing->Registers, &_Thread_Executing->Registers );
/* switch to Floating_point_task_2 */
}
rtems_task Floating_point_task_2(
rtems_task_argument argument
)
{
Thread_Control *executing;
FP_DECLARE;
context_switch_save_restore_idle_time = benchmark_timer_read();
executing = _Thread_Executing;
_Thread_Executing =
(Thread_Control *) _Thread_Ready_chain[FP1_PRIORITY].first;
FP_LOAD( 1.0 );
/* do not force context switch */
_Context_Switch_necessary = false;
_Thread_Disable_dispatch();
benchmark_timer_initialize();
#if (CPU_HARDWARE_FP == 1) || (CPU_SOFTWARE_FP == 1)
_Context_Save_fp( &executing->fp_context );
_Context_Restore_fp( &_Thread_Executing->fp_context );
#endif
_Context_Switch( &executing->Registers, &_Thread_Executing->Registers );
/* switch to Floating_point_task_1 */
context_switch_save_restore_initted_time = benchmark_timer_read();
complete_test();
}
void _Thread_Start_multitasking( void )
{
Per_CPU_Control *cpu_self = _Per_CPU_Get();
Thread_Control *heir;
#if defined(RTEMS_SMP)
_Per_CPU_State_change( cpu_self, PER_CPU_STATE_UP );
/*
* Threads begin execution in the _Thread_Handler() function. This
* function will set the thread dispatch disable level to zero.
*/
cpu_self->thread_dispatch_disable_level = 1;
#endif
heir = _Thread_Get_heir_and_make_it_executing( cpu_self );
/*
* Get the init task(s) running.
*
* Note: Thread_Dispatch() is normally used to dispatch threads. As
* part of its work, Thread_Dispatch() restores floating point
* state for the heir task.
*
* This code avoids Thread_Dispatch(), and so we have to restore
* (actually initialize) the floating point state "by hand".
*
* Ignore the CPU_USE_DEFERRED_FP_SWITCH because we must always
* switch in the first thread if it is FP.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
/*
* don't need to worry about saving BSP's floating point state
*/
if ( heir->fp_context != NULL )
_Context_Restore_fp( &heir->fp_context );
#endif
_Profiling_Thread_dispatch_disable( cpu_self, 0 );
#if defined(RTEMS_SMP)
/*
* The _CPU_Context_Restart_self() implementations usually assume that self
* context is executing.
*
* FIXME: We have a race condition here in case another thread already
* performed scheduler operations and moved our heir thread to another
* processor. The time frame for this is likely too small to be practically
* relevant.
*/
_CPU_Context_Set_is_executing( &heir->Registers, true );
#endif
#if defined(_CPU_Start_multitasking)
_CPU_Start_multitasking( &heir->Registers );
#else
_CPU_Context_Restart_self( &heir->Registers );
#endif
}
rtems_task Low_task(
rtems_task_argument argument
)
{
Scheduler_priority_Context *scheduler_context =
_Scheduler_priority_Get_context( _Scheduler_Get( _Thread_Get_executing() ) );
Thread_Control *executing;
context_switch_no_fp_time = benchmark_timer_read();
executing = _Thread_Get_executing();
Low_tcb = executing;
benchmark_timer_initialize();
_Context_Switch( &executing->Registers, &executing->Registers );
context_switch_self_time = benchmark_timer_read();
_Context_Switch(&executing->Registers, &Middle_tcb->Registers);
context_switch_another_task_time = benchmark_timer_read();
set_thread_executing(
(Thread_Control *) _Chain_First(&scheduler_context->Ready[FP1_PRIORITY])
);
/* do not force context switch */
set_thread_dispatch_necessary( false );
thread_disable_dispatch();
benchmark_timer_initialize();
#if (CPU_HARDWARE_FP == 1) || (CPU_SOFTWARE_FP == 1)
_Context_Restore_fp( &_Thread_Get_executing()->fp_context );
#endif
_Context_Switch(
&executing->Registers,
&_Thread_Get_executing()->Registers
);
}
void _Thread_Start_multitasking( void )
{
/*
* The system is now multitasking and completely initialized.
* This system thread now "hides" in a single processor until
* the system is shut down.
*/
_System_state_Set( SYSTEM_STATE_UP );
_Thread_Dispatch_necessary = false;
_Thread_Executing = _Thread_Heir;
/*
* Get the init task(s) running.
*
* Note: Thread_Dispatch() is normally used to dispatch threads. As
* part of its work, Thread_Dispatch() restores floating point
* state for the heir task.
*
* This code avoids Thread_Dispatch(), and so we have to restore
* (actually initialize) the floating point state "by hand".
*
* Ignore the CPU_USE_DEFERRED_FP_SWITCH because we must always
* switch in the first thread if it is FP.
*/
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
/*
* don't need to worry about saving BSP's floating point state
*/
if ( _Thread_Heir->fp_context != NULL )
_Context_Restore_fp( &_Thread_Heir->fp_context );
#endif
#if defined(_CPU_Start_multitasking)
_CPU_Start_multitasking( &_Thread_BSP_context, &_Thread_Heir->Registers );
#else
_Context_Switch( &_Thread_BSP_context, &_Thread_Heir->Registers );
#endif
}
rtems_task Low_task(
rtems_task_argument argument
)
{
Thread_Control *executing;
Chain_Control *ready_queues;
ready_queues = (Chain_Control *) _Scheduler.information;
context_switch_no_fp_time = benchmark_timer_read();
executing = _Thread_Executing;
Low_tcb = executing;
benchmark_timer_initialize();
_Context_Switch( &executing->Registers, &executing->Registers );
context_switch_self_time = benchmark_timer_read();
_Context_Switch(&executing->Registers, &Middle_tcb->Registers);
context_switch_another_task_time = benchmark_timer_read();
_Thread_Executing =
(Thread_Control *) _Chain_First(&ready_queues[FP1_PRIORITY]);
/* do not force context switch */
_Thread_Dispatch_necessary = false;
_Thread_Disable_dispatch();
benchmark_timer_initialize();
#if (CPU_HARDWARE_FP == 1) || (CPU_SOFTWARE_FP == 1)
_Context_Restore_fp( &_Thread_Executing->fp_context );
#endif
_Context_Switch( &executing->Registers, &_Thread_Executing->Registers );
}
void _Thread_Life_action_handler(
Thread_Control *executing,
Thread_Action *action,
ISR_lock_Context *lock_context
)
{
Thread_Life_state previous_life_state;
Per_CPU_Control *cpu_self;
(void) action;
previous_life_state = executing->Life.state;
executing->Life.state = previous_life_state | THREAD_LIFE_PROTECTED;
_Thread_State_release( executing, lock_context );
if ( _Thread_Is_life_terminating( previous_life_state ) ) {
_User_extensions_Thread_terminate( executing );
} else {
_Assert( _Thread_Is_life_restarting( previous_life_state ) );
_User_extensions_Thread_restart( executing );
}
cpu_self = _Thread_Dispatch_disable();
if ( _Thread_Is_life_terminating( previous_life_state ) ) {
cpu_self = _Thread_Wait_for_join( executing, cpu_self );
_Thread_Make_zombie( executing );
/* FIXME: Workaround for https://devel.rtems.org/ticket/2751 */
cpu_self->dispatch_necessary = true;
_Assert( cpu_self->heir != executing );
_Thread_Dispatch_enable( cpu_self );
RTEMS_UNREACHABLE();
}
_Assert( _Thread_Is_life_restarting( previous_life_state ) );
_Thread_State_acquire( executing, lock_context );
_Thread_Change_life_locked(
executing,
THREAD_LIFE_PROTECTED | THREAD_LIFE_RESTARTING,
0,
0
);
_Thread_State_release( executing, lock_context );
_Assert(
_Watchdog_Get_state( &executing->Timer.Watchdog ) == WATCHDOG_INACTIVE
);
_Assert(
executing->current_state == STATES_READY
|| executing->current_state == STATES_SUSPENDED
);
_User_extensions_Destroy_iterators( executing );
_Thread_Load_environment( executing );
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
if ( executing->fp_context != NULL ) {
_Context_Restore_fp( &executing->fp_context );
}
#endif
_Context_Restart_self( &executing->Registers );
RTEMS_UNREACHABLE();
}
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 );
}
