stk::TaskW< _Weight, _StackSize, _AccessMode > Class Template Reference

Partial implementation of the user task with a compile-time scheduling weight. Use when the kernel is configured with SwitchStrategySmoothWeightedRoundRobin. More...

#include <stk_helper.h>

Inheritance diagram for stk::TaskW< _Weight, _StackSize, _AccessMode >:

Collaboration diagram for stk::TaskW< _Weight, _StackSize, _AccessMode >:

Public Types
enum	{ STACK_SIZE = _StackSize }

Public Member Functions
const Word *	GetStack () const override
	Get pointer to the stack memory.
size_t	GetStackSize () const override
	Get number of elements of the stack memory array.
EAccessMode	GetAccessMode () const override
	Get pointer to the stack memory.
Weight	GetWeight () const override
	Get static base weight of the task.
virtual void	Run ()=0
	Entry point of the user task.
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 const char *	GetTraceName () const
	Get task trace name set by application.
virtual size_t	GetStackSpace () const
	Get available stack space.

Protected Member Functions
	TaskW (const TaskW &)=delete
TaskW &	operator= (const TaskW &)=delete
	TaskW ()
	Initializes task instance and zero-initializes its internal stack memory.
	~TaskW ()=default
	Destructor.

Private Attributes
StackMemoryDef< _StackSize >::Type	m_stack
	Stack memory region, 16-byte aligned.

Detailed Description

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>
class stk::TaskW< _Weight, _StackSize, _AccessMode >

Partial implementation of the user task with a compile-time scheduling weight. Use when the kernel is configured with SwitchStrategySmoothWeightedRoundRobin.

Template Parameters

_Weight	Static scheduling weight (positive, non-zero 24-bit integer). Higher values cause this task to receive proportionally more CPU time.
_StackSize	Stack size in elements of Word.
_AccessMode	Hardware access mode (ACCESS_USER or ACCESS_PRIVILEGED).

Note

Hard Real-Time mode (KERNEL_HRT) is not supported for weighted tasks. OnDeadlineMissed() will trigger an assertion if HRT scheduling is attempted.

See Task for full usage example, implementation guidance, and TrustZone Non-Secure inheritance notes.

Definition at line 144 of file stk_helper.h.

Member Enumeration Documentation

anonymous enum

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

anonymous enum

Enumerator
STACK_SIZE

Definition at line 152 of file stk_helper.h.

{ STACK_SIZE = _StackSize }; 

Constructor & Destructor Documentation

TaskW() [1/2]

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

stk::TaskW< _Weight, _StackSize, _AccessMode >::TaskW ( const TaskW< _Weight, _StackSize, _AccessMode > & )

protecteddelete

Referenced by operator=().

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TaskW() [2/2]

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

stk::TaskW< _Weight, _StackSize, _AccessMode >::TaskW ( )

inlineprotected

Initializes task instance and zero-initializes its internal stack memory.

The constructor is protected to ensure that the Task class can only be instantiated through a derived subclass. It handles the allocation (if applicable) and zero-initialization of the m_stack member based on the _StackSize template parameter.

Definition at line 169 of file stk_helper.h.

: m_stack() {}

References m_stack.

~TaskW()

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

stk::TaskW< _Weight, _StackSize, _AccessMode >::~TaskW ( )

protecteddefault

Destructor.

Note

Protected by design. Prevents unsafe polymorphic delete.

References STK_VIRT_DTOR.

Member Function Documentation

GetAccessMode()

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

EAccessMode stk::TaskW< _Weight, _StackSize, _AccessMode >::GetAccessMode ( ) const

inlineoverridevirtual

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.

Implements stk::ITask.

Definition at line 156 of file stk_helper.h.

{ return _AccessMode; }

GetStack()

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

const Word * stk::TaskW< _Weight, _StackSize, _AccessMode >::GetStack ( ) const

inlineoverridevirtual

Get pointer to the stack memory.

Implements stk::IStackMemory.

Definition at line 154 of file stk_helper.h.

{ return const_cast<Word *>(m_stack); }

References m_stack.

GetStackSize()

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

size_t stk::TaskW< _Weight, _StackSize, _AccessMode >::GetStackSize ( ) const

inlineoverridevirtual

Get number of elements of the stack memory array.

Implements stk::IStackMemory.

Definition at line 155 of file stk_helper.h.

{ return _StackSize; }

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 430 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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GetTraceName()

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

inlinevirtualinherited

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 FrtosTask, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Definition at line 866 of file stk_common.h.

{ return nullptr; }

GetWeight()

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

Weight stk::TaskW< _Weight, _StackSize, _AccessMode >::GetWeight ( ) const

inlineoverridevirtual

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 from stk::ITask.

Definition at line 157 of file stk_helper.h.

{ return _Weight; }

OnDeadlineMissed()

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

inlinevirtualinherited

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 FrtosTask, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Definition at line 842 of file stk_common.h.

{ STK_UNUSED(duration); }

References STK_UNUSED.

OnExit()

virtual void stk::ITask::OnExit ( )

inlinevirtualinherited

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 FrtosTask, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Definition at line 852 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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operator=()

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

TaskW & stk::TaskW< _Weight, _StackSize, _AccessMode >::operator= ( const TaskW< _Weight, _StackSize, _AccessMode > & )

protecteddelete

References TaskW().

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Run()

virtual void stk::ITask::Run ( )

pure virtualinherited

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 FrtosTask, stk::time::TimerHost::TimerWorkerTask, StkThread, and TaskWrapper.

Member Data Documentation

m_stack

template<Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>

StackMemoryDef<_StackSize>::Type stk::TaskW< _Weight, _StackSize, _AccessMode >::m_stack

private

Stack memory region, 16-byte aligned.

Definition at line 177 of file stk_helper.h.

Referenced by GetStack(), and TaskW().

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

• stk_helper.h