stk::ITask Class Reference

Interface for a user task. More...

#include <stk_common.h>

Inheritance diagram for stk::ITask:

Collaboration diagram for stk::ITask:

Public Member Functions
virtual void	Run ()=0
	Entry point of the user task.
virtual EAccessMode	GetAccessMode () const =0
	Get pointer to the stack memory.
virtual void	OnDeadlineMissed (uint32_t duration)
	Called by the scheduler if deadline of the task is missed when Kernel is operating in Hard Real-Time mode (see stk::KERNEL_HRT).
virtual void	OnExit ()
	Called by the kernel before removal from the scheduling (see stk::KERNEL_DYNAMIC).
virtual Weight	GetWeight () const
	Get static base weight of the task.
virtual Timeout	GetTimeSlice () const
	Get time-slice quantum of the task (ticks). KERNEL_TIMESLICE only.
virtual const char *	GetTraceName () const
	Get task trace name set by application.
virtual const Word *	GetStack () const =0
	Get pointer to the stack memory.
virtual size_t	GetStackSize () const =0
	Get number of elements of the stack memory array.
virtual size_t	GetStackSpace () const
	Get available stack space.

Protected Member Functions
	~ITask ()=default
	Destructor.

Detailed Description

Interface for a user task.

Note

Inherit this interface by your thread/task class to make it schedulable by the Kernel.

Usage example:

class MyTask : public stk::Task<256, ACCESS_USER>
{
    void Run() override
    {
        while (true)
        {
            // task logic here
        }
    }
};
 
MyTask task1, task2;
kernel.AddTask(&task1);
kernel.AddTask(&task2);

Examples

D:/SVN/private/stk/interop/c/include/stk_c.h.

Definition at line 823 of file stk_common.h.

Constructor & Destructor Documentation

~ITask()

stk::ITask::~ITask ( )

protecteddefault

Destructor.

Note

Protected by design. Prevents unsafe polymorphic delete.

Member Function Documentation

GetAccessMode()

virtual EAccessMode stk::ITask::GetAccessMode ( ) const

pure virtual

Get pointer to the stack memory.

Note

Optional. ARM TrustZone only.

Returns

Pointer to the Secure stack memory.

Get up to (STK_MPU_TASK_REGIONS - 1) application-defined MPU regions for this task.

When STK_MPU_STACK_GUARD is enabled, each task owns STK_MPU_TASK_REGIONS (2, 4, 6, 8, 12 or 16, see STK_MPU_TASK_REGIONS) hardware MPU region slots. Slot 0 is always the automatic stack guard, computed by the driver from the task's own stack memory (see IStackMemory::GetStack/GetStackSize). This hook supplies the remaining STK_MPU_TASK_REGIONS-1 slots, letting an application additionally sandbox a task to e.g. a private data buffer, a specific peripheral block, or a shared IPC region - on top of its stack guard.

Returns

Pointer to a constant MpuRegionList containing up to (STK_MPU_TASK_REGIONS - 1) region descriptors, or nullptr if no extra task regions are configured. Array element i is applied at task-relative region index i +1 (i.e. the slots following the stack guard).

Note

Optional. Only consulted when STK_MPU_STACK_GUARD is enabled; a no-op on platforms/builds without MPU stack-guard support.

Read once, when the task is bound via Kernel::AddTask() (through IPlatform::InitStack()), not re-evaluated on every context switch. The underlying MpuRegionList instance referenced by the returned pointer must remain valid (e.g. a static const instance); a stack-local temporary is invalid once this function returns.

Warning

An element count greater than (STK_MPU_TASK_REGIONS - 1) is clamped by the driver (STK_ASSERT fires in debug builds); only the first STK_MPU_TASK_REGIONS-1 entries are ever applied.

class MyTask : public stk::Task<256, stk::ACCESS_USER>
{
    static constexpr stk::MpuRegionConfig s_extra_regions[] =
    {
        { .addr = MY_BUFFER_ADDR, .size = MY_BUFFER_SIZE,
          .access_perm = stk::hw::mpu::ACCESS_FULL,
          .mem_type    = stk::hw::mpu::TYPE_NORMAL_CACHEABLE,
          .exec        = stk::hw::mpu::EXEC_NEVER },
    };
 
    const stk::MpuRegionList *GetMpuRegions() const override
    {
        static const stk::MpuRegionList mpu_regions(s_extra_regions, 1U);
        return &mpu_regions;
    }
 
    void Run() override { ... }
};

See also

TaskMpu::Configure, IPlatform::InitStack, MpuRegionList

Get hardware access mode of the user task.

Implemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::pthread::PthreadTask, stk::Task< _StackSize, _AccessMode >, stk::TaskW< _Weight, _StackSize, _AccessMode >, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Referenced by stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelTask::Bind().

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GetStack()

virtual const Word * stk::IStackMemory::GetStack ( ) const

pure virtualinherited

Get pointer to the stack memory.

Implemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::pthread::PthreadTask, stk::StackMemoryWrapper< _StackSize >, stk::StackMemoryWrapper< STACK_SIZE_MIN >, stk::StackMemoryWrapper<((32U))>, stk::Task< _StackSize, _AccessMode >, stk::TaskW< _Weight, _StackSize, _AccessMode >, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Referenced by stk::Kernel< stk::KERNEL_DYNAMIC|stk::KERNEL_SYNC|stk::KERNEL_TICKLESS,(16U), stk::SwitchStrategyFP32, stk::PlatformDefault >::AllocateNewTask(), GetStackSpace(), stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelTask::IsMemoryOfSP(), stk::Kernel< stk::KERNEL_DYNAMIC|stk::KERNEL_SYNC|stk::KERNEL_TICKLESS,(16U), stk::SwitchStrategyFP32, stk::PlatformDefault >::StateSwitch(), and stk::Kernel< stk::KERNEL_DYNAMIC|stk::KERNEL_SYNC|stk::KERNEL_TICKLESS,(16U), stk::SwitchStrategyFP32, stk::PlatformDefault >::StateWake().

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GetStackSize()

virtual size_t stk::IStackMemory::GetStackSize ( ) const

pure virtualinherited

Get number of elements of the stack memory array.

Implemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::pthread::PthreadTask, stk::StackMemoryWrapper< _StackSize >, stk::StackMemoryWrapper< STACK_SIZE_MIN >, stk::StackMemoryWrapper<((32U))>, stk::Task< _StackSize, _AccessMode >, stk::TaskW< _Weight, _StackSize, _AccessMode >, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Referenced by GetStackSpace(), and stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelTask::IsMemoryOfSP().

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GetStackSpace()

virtual size_t stk::IStackMemory::GetStackSpace ( ) const

inlinevirtualinherited

Get available stack space.

Returns

Number of elements of the stack memory array remaining on the stack (computed via the watermark pattern). Returns 0 if the stack has been fully used or the watermark STK_STACK_MEMORY_FILLER was overwritten.

Warning

Stack type: Bottom to Top (index[0]).

Definition at line 465 of file stk_common.h.

    {
        const ArrayView<const Word> stack(GetStack(), GetStackSize());
        const size_t total_size = stack.GetSize();
        size_t space = 0U;
 
        for (size_t i = 0U; i < total_size; ++i)
        {
            if (stack[i] == STK_STACK_MEMORY_FILLER)
            {
                space = i + 1U;
            }
            else
            {
                break; // terminate loop as soon as watermark ends
            }
        }
 
        return space;
    }

References stk::ArrayView< T >::GetSize(), GetStack(), GetStackSize(), and STK_STACK_MEMORY_FILLER.

Referenced by FrtosTask::GetStackHighWaterMark(), and osThreadGetStackSpace().

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GetTimeSlice()

virtual Timeout stk::ITask::GetTimeSlice ( ) const

inlinevirtual

Get time-slice quantum of the task (ticks). KERNEL_TIMESLICE only.

Returns

Number of ticks the task may run before being rotated behind its same-priority peers, or NO_TIME_SLICE (default) to run until it blocks, yields or is preempted.

Note

Read once when the task is bound by Kernel::AddTask(). Use IKernelService::SetTimeSlice() to change it at run-time.

See also

stk::KERNEL_TIMESLICE, IKernelService::SetTimeSlice

Reimplemented in anonymous_namespace{threadx_stk.cpp}::StkThread, and anonymous_namespace{threadx_stk.cpp}::StkTimerThread.

Definition at line 937 of file stk_common.h.

{ return NO_TIME_SLICE; }

References stk::NO_TIME_SLICE.

Referenced by stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelTask::Bind().

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GetTraceName()

virtual const char * stk::ITask::GetTraceName ( ) const

inlinevirtual

Get task trace name set by application.

Returns

Null-terminated name string, or NULL if unused.

Note

Used for debugging and tracing only (e.g. SEGGER SystemView). Kernel does not interpret this value.

Reimplemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::pthread::PthreadTask, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Definition at line 944 of file stk_common.h.

{ return nullptr; }

GetWeight()

virtual Weight stk::ITask::GetWeight ( ) const

inlinevirtual

Get static base weight of the task.

Returns

Static weight value of the task (must be non-zero, positive 24-bit number).

See also

SwitchStrategyFixedPriority, SwitchStrategySmoothWeightedRoundRobin, IKernelTask::GetWeight, IKernelService::InheritWeight, IKernelService::RestoreWeight

Reimplemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::pthread::PthreadTask, stk::TaskW< _Weight, _StackSize, _AccessMode >, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Definition at line 928 of file stk_common.h.

{ return DEFAULT_WEIGHT; }

References stk::DEFAULT_WEIGHT.

Referenced by stk::ISyncObject::FindWeightHigherThan().

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OnDeadlineMissed()

virtual void stk::ITask::OnDeadlineMissed ( uint32_t duration )

inlinevirtual

Called by the scheduler if deadline of the task is missed when Kernel is operating in Hard Real-Time mode (see stk::KERNEL_HRT).

Parameters

[in]

duration

Elapsed active time in ticks at the point the deadline was detected. Always greater than the task's configured deadline (ticks).

Note

Optional handler. Use it for fault logging.

After this call returns, IPlatform::ProcessHardFault() is invoked and the system enters a safe state. This function should not attempt to recover scheduling.

Reimplemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::time::TimerHost::TimerWorkerTask, and StkThread.

Definition at line 911 of file stk_common.h.

{ STK_UNUSED(duration); }

References STK_UNUSED.

OnExit()

virtual void stk::ITask::OnExit ( )

inlinevirtual

Called by the kernel before removal from the scheduling (see stk::KERNEL_DYNAMIC).

Note

The task's stack is no longer in use but the ITask object itself is still valid.

The default no-op implementation is sufficient for detached tasks. Override to implement join semantics (signal a waiting joiner).

Called in kernel/tick context - keep it short. ISR-safe primitives only (e.g. stk::sync::Semaphore::Signal(), stk::sync::EventFlags::Set()).

KERNEL_DYNAMIC only. Never called in KERNEL_STATIC mode.

Reimplemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::pthread::PthreadTask, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Definition at line 921 of file stk_common.h.

{}

Referenced by stk::Kernel< stk::KERNEL_DYNAMIC|stk::KERNEL_SYNC|stk::KERNEL_TICKLESS,(16U), stk::SwitchStrategyFP32, stk::PlatformDefault >::RemoveTask().

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Run()

virtual void stk::ITask::Run ( )

pure virtual

Entry point of the user task.

Note

Called by the Kernel when the task is scheduled for execution. Implement this method with the task's main logic.

Warning

If Kernel is configured as KERNEL_STATIC, the body must contain an infinite loop.

void Run( override)
{
    while (true)
    {
        // task logic here
    }
}

Implemented in anonymous_namespace{threadx_stk.cpp}::StkThread, anonymous_namespace{threadx_stk.cpp}::StkTimerThread, FrtosTask, stk::pthread::PthreadTask, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

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The documentation for this class was generated from the following file:

• stk_common.h