Interface for the kernel services exposed to the user processes during run-time when Kernel started scheduling the processes. More...

#include <stk_common.h>

Inheritance diagram for stk::IKernelService:

Public Member Functions
virtual TId	GetTid () const =0
	Get thread Id of the currently running task.
virtual Ticks	GetTicks () const =0
	Get number of ticks elapsed since kernel start.
virtual int32_t	GetTickResolution () const =0
	Get number of microseconds in one tick.
virtual void	Delay (Timeout ticks)=0
	Delay calling process.
virtual void	Sleep (Timeout ticks)=0
	Put calling process into a sleep state.
virtual void	SleepUntil (Ticks timestamp)=0
	Put calling process into a sleep state until the specified timestamp.
virtual void	SwitchToNext ()=0
	Notify scheduler to switch to the next task (yield).
virtual IWaitObject *	Wait (ISyncObject sobj, IMutex mutex, Timeout timeout)=0
	Put calling process into a waiting state until synchronization object is signaled or timeout occurs.

Static Public Member Functions
static IKernelService *	GetInstance ()
	Get CPU-local instance of the kernel service.

Detailed Description

Interface for the kernel services exposed to the user processes during run-time when Kernel started scheduling the processes.

Note: State design pattern: this interface represents the kernel's active running state. It becomes valid only after IKernel::Start() is called. Before that point the kernel is in an idle/unstarted state and this interface must not be used. Obtain the CPU-local instance via IKernelService::GetInstance().

Definition at line 928 of file stk_common.h.

Member Function Documentation

◆ Delay()

virtual void stk::IKernelService::Delay ( Timeout ticks )

pure virtual

Delay calling process.

Note: Unlike Sleep this function delays code execution by spinning in a loop until deadline expiry.; Use with care in HRT mode to avoid missed deadline (see stk::KERNEL_HRT, ITask::OnDeadlineMissed).

Parameters

[in] ticks Delay time (ticks).

Warning: ISR-unsafe. Calling from an ISR context is not permitted and will trigger an assertion.

See also: Delay

Implemented in stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelService, stk::test::KernelServiceMock, and stk::test::stk::KernelServiceMock.

Referenced by stk::Delay().

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◆ GetInstance()

IKernelService * IKernelService::GetInstance ( )

static

Get CPU-local instance of the kernel service.

Definition at line 69 of file stktest.cpp.

{
    return g_KernelService;
}

References stk::test::g_KernelService.

Referenced by stk::Delay(), stk::GetTickResolution(), stk::GetTicks(), stk::GetTid(), stk::GetTimeNowMs(), stk::Sleep(), stk::SleepUntil(), stk::test::TEST(), stk::test::TEST(), stk::test::TEST(), stk::test::TEST(), stk::test::TEST(), stk::test::TEST(), stk::test::TEST(), stk::test::TEST(), stk::test::Test_SyncWait(), stk::sync::Mutex::TimedLock(), stk::sync::ConditionVariable::Wait(), stk::sync::Event::Wait(), stk::sync::Semaphore::Wait(), and stk::Yield().

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◆ GetTickResolution()

virtual int32_t stk::IKernelService::GetTickResolution ( ) const

pure virtual

Get number of microseconds in one tick.

Note: Tick is a periodicity of the system timer expressed in microseconds.; ISR-safe.

Returns: Microseconds in one tick.

Implemented in stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelService, stk::test::KernelServiceMock, and stk::test::stk::KernelServiceMock.

Referenced by stk::GetTickResolution(), and stk::GetTimeNowMs().

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◆ GetTicks()

virtual Ticks stk::IKernelService::GetTicks ( ) const

pure virtual

Get number of ticks elapsed since kernel start.

Returns: Ticks.

Note: ISR-safe.

Implemented in stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelService, stk::test::KernelServiceMock, and stk::test::stk::KernelServiceMock.

Referenced by stk::GetTicks(), and stk::GetTimeNowMs().

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◆ GetTid()

virtual TId stk::IKernelService::GetTid ( ) const

pure virtual

Get thread Id of the currently running task.

Returns: Thread Id.

Warning: ISR-unsafe. Calling from an ISR context is not permitted and will trigger an assertion.

Implemented in stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelService, stk::test::KernelServiceMock, and stk::test::stk::KernelServiceMock.

Referenced by stk::GetTid(), and stk::sync::Mutex::TimedLock().

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◆ Sleep()

virtual void stk::IKernelService::Sleep ( Timeout ticks )

pure virtual

Put calling process into a sleep state.

Note: Unlike Delay this function does not waste CPU cycles and allows kernel to put CPU into a low-power state.; Unsupported in HRT mode (see stk::KERNEL_HRT); in HRT mode tasks sleep automatically according to their periodicity and workload.

Parameters

[in] ticks Sleep time (ticks).

Warning: ISR-unsafe. Calling from an ISR context is not permitted and will trigger an assertion.

Implemented in stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelService, stk::test::KernelServiceMock, and stk::test::stk::KernelServiceMock.

Referenced by stk::Sleep().

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◆ SleepUntil()

virtual void stk::IKernelService::SleepUntil ( Ticks timestamp )

pure virtual

Put calling process into a sleep state until the specified timestamp.

Note: Unlike Delay this function does not waste CPU cycles and allows kernel to put CPU into a low-power state.; Unsupported in HRT mode (see stk::KERNEL_HRT); in HRT mode tasks sleep automatically according to their periodicity and workload.

Parameters

[in] timestamp Absolute timestamp (ticks).

Warning: ISR-unsafe. Calling from an ISR context is not permitted and will trigger an assertion.

Implemented in stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelService, stk::test::KernelServiceMock, and stk::test::stk::KernelServiceMock.

Referenced by stk::SleepUntil().

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◆ SwitchToNext()

virtual void stk::IKernelService::SwitchToNext ( )

pure virtual

Notify scheduler to switch to the next task (yield).

Note: A cooperation mechanism in HRT mode (see stk::KERNEL_HRT).

Warning: ISR-unsafe.

Implemented in stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelService, stk::test::KernelServiceMock, and stk::test::stk::KernelServiceMock.

Referenced by stk::Yield().

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◆ Wait()

virtual IWaitObject * stk::IKernelService::Wait	(	ISyncObject *	sobj,
		IMutex *	mutex,
		Timeout	timeout )

pure virtual

Put calling process into a waiting state until synchronization object is signaled or timeout occurs.

Note: This function implements core blocking logic using the Monitor pattern to ensure atomicity between state check and suspension.; The kernel automatically unlocks the provided mutex before the task is suspended and re-locks it before this function returns.

Parameters

[in]	sobj	Synchronization object to wait on.
[in]	mutex	Mutex protecting the state of the synchronization object.
[in]	timeout	Maximum wait time (ticks). Use `WAIT_INFINITE` to block indefinitely, use `NO_WAIT` to poll without blocking.

Returns: Pointer to the wait object representing this wait operation (always non-NULL). The caller must check IWaitObject::IsTimeout() after this function returns to determine whether the wake was caused by a signal or by timeout expiry. The returned pointer is valid until the calling task re-enters a wait or the wait object is explicitly released by the kernel. The return value is guaranteed non nullptr and points to a valid IWaitObject.