stk::SyncObjectBase Class Reference

Default, storage-owning implementation of ISyncObject. More...

#include <stk_helper.h>

Inheritance diagram for stk::SyncObjectBase:

Collaboration diagram for stk::SyncObjectBase:

Public Types
typedef DLHeadType	ListHeadType
	List head type for ISyncObject elements.
typedef DLEntryType	ListEntryType
	List entry type of ISyncObject elements.
enum
	A tag for type-safe casts done by CastListEntryToParent. More...
typedef DListEntry< ISyncObject, TClosedLoop >	DLEntryType
	Convenience alias for this entry type. Used to avoid repeating the full template spelling.
typedef DListHead< ISyncObject, TClosedLoop >	DLHeadType
	Convenience alias for the corresponding list head type.

Public Member Functions
void	AddWaitObject (IWaitObject *wobj) override
	Called by kernel when a new task starts waiting on this event.
void	RemoveWaitObject (IWaitObject *wobj) override
	Called by kernel when a waiting task is being removed (timeout expired, wait aborted, task terminated etc.).
const IWaitObject::ListHeadType &	GetWaitList () const override
	Get list of tasks blocked on this object.
virtual bool	Tick (Timeout elapsed_ticks)
	Called by kernel on every system tick to handle timeout logic of waiting tasks.
Weight	FindWeightHigherThan (Weight comp) const
	Find higher weight within linked wait objects.
DLHeadType *	GetHead ()
	Get the list head this entry currently belongs to.
DLEntryType *	GetNext ()
	Get the next entry in the list.
DLEntryType *	GetPrev ()
	Get the previous entry in the list.
bool	IsLinked () const
	Check whether this entry is currently a member of any list.
	operator ISyncObject * ()
	Implicit conversion to a mutable pointer to the host object (T).
	operator const ISyncObject * () const
	Implicit conversion to a const pointer to the host object (T).

Static Public Member Functions
static void	AddWaitObject (IWaitObject::ListHeadType &wlist, IWaitObject *wobj)
	Called by kernel when a new task starts waiting on this event.
static void	RemoveWaitObject (IWaitObject::ListHeadType &wlist, IWaitObject *wobj)
	Called by kernel when a waiting task is being removed (timeout expired, wait aborted, task terminated etc.).
static void	WakeOne (IWaitObject::ListHeadType &wlist)
	Wake the first task in the wait list (FIFO order).
static void	WakeAll (IWaitObject::ListHeadType &wlist)
	Wake all tasks currently in the wait list.

Protected Member Functions
	SyncObjectBase ()
	Constructor.
	~SyncObjectBase ()=default
	Destructor.
void	WakeOne () override
	Wake the first task in the wait list (FIFO order).
void	WakeAll () override
	Wake all tasks currently in the wait list.
IWaitObject::ListHeadType &	GetWaitList () override
	Get list of tasks blocked on this object.

Protected Attributes
IWaitObject::ListHeadType	m_wait_list
	Tasks blocked on this object.

Private Member Functions
void	Link (DLHeadType *head, DLEntryType *next, DLEntryType *prev)
	Wire this entry into a list between prev and next.
void	Unlink ()
	Remove this entry from its current list.

Private Attributes
DLHeadType *	m_head
	Owning list head, or NULL when the entry is not linked.
DLEntryType *	m_next
	Next entry in the list, or NULL (open list boundary) / first entry (closed loop).
DLEntryType *	m_prev
	Previous entry in the list, or NULL (open list boundary) / last entry (closed loop).

Friends
class	IKernelService

Detailed Description

Default, storage-owning implementation of ISyncObject.

Owns the intrusive wait list (m_wait_list) and provides the standard add/remove/wake bookkeeping used by all built-in synchronization primitives (Mutex, Event, Semaphore, ConditionVariable, ...). m_wait_list is protected rather than private: primitives that privately inherit this class are permitted to touch it directly on the hot path (see e.g. Mutex::Unlock) instead of going through the virtual GetWaitList() accessor.

Note

Not every ISyncObject need derive from this class - an implementation with a different storage strategy (e.g. a cross-domain TrustZone wrapper) may implement ISyncObject directly instead.

On ARM TrustZone Non-Secure builds (_STK_CORTEX_M_TRUSTZONE_NON_SECURE), derives from tz::nsec::NsSyncObject instead of ISyncObject directly. Unlike ITask, ISyncObject has no explicit deregistration call, so NsSyncObject's destructor is the only mechanism that frees the Secure-side proxy pool slot for a dynamically-allocated sync object - without it, destroying sync objects at runtime would permanently exhaust the pool.

See also

tz::nsec::NsSyncObject

Definition at line 242 of file stk_helper.h.

Member Typedef Documentation

DLEntryType

typedef DListEntry<ISyncObject, TClosedLoop> stk::util::DListEntry< ISyncObject, TClosedLoop >::DLEntryType

inherited

Convenience alias for this entry type. Used to avoid repeating the full template spelling.

Definition at line 75 of file stk_linked_list.h.

DLHeadType

typedef DListHead<ISyncObject, TClosedLoop> stk::util::DListEntry< ISyncObject, TClosedLoop >::DLHeadType

inherited

Convenience alias for the corresponding list head type.

Definition at line 80 of file stk_linked_list.h.

ListEntryType

typedef DLEntryType stk::ISyncObject::ListEntryType

inherited

List entry type of ISyncObject elements.

Definition at line 577 of file stk_common.h.

ListHeadType

typedef DLHeadType stk::ISyncObject::ListHeadType

inherited

List head type for ISyncObject elements.

Definition at line 572 of file stk_common.h.

Member Enumeration Documentation

anonymous enum

anonymous enum

inherited

A tag for type-safe casts done by CastListEntryToParent.

See also

CastListEntryToParent.

Definition at line 70 of file stk_linked_list.h.

{ DLEntryTag = 1 };

Constructor & Destructor Documentation

SyncObjectBase()

stk::SyncObjectBase::SyncObjectBase ( )

inlineexplicitprotected

Constructor.

Note

Can not be standalone object, must be inherited by the implementation.

Definition at line 271 of file stk_helper.h.

                              : m_wait_list()
    {}

References m_wait_list.

~SyncObjectBase()

stk::SyncObjectBase::~SyncObjectBase ( )

protecteddefault

Destructor.

Note

Protected by design. Prevents unsafe polymorphic delete.

Member Function Documentation

AddWaitObject() [1/2]

void stk::ISyncObject::AddWaitObject ( IWaitObject::ListHeadType & wlist, IWaitObject * wobj )

inlinestaticinherited

Called by kernel when a new task starts waiting on this event.

Parameters

[in]

wobj

Wait object representing blocked task.

Note

Utility for AddWaitObject and ARM TrustZone support.

Definition at line 583 of file stk_common.h.

    {
        STK_ASSERT(wobj->GetHead() == nullptr);
        wlist.LinkBack(wobj);
    }

References stk::util::DListEntry< T, TClosedLoop >::GetHead(), stk::util::DListHead< T, TClosedLoop >::LinkBack(), and STK_ASSERT.

Referenced by stk::SyncObjectBase::AddWaitObject(), and stk::Kernel< TMode, TSize, TStrategy, TPlatform >::KernelTask::WaitObject::SetupWait().

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AddWaitObject() [2/2]

void stk::SyncObjectBase::AddWaitObject ( IWaitObject * wobj )

inlineoverridevirtual

Called by kernel when a new task starts waiting on this event.

Parameters

[in]

wobj

Wait object representing blocked task.

Note

Must be called inside the critical section (see hw::CriticalSection, sync::ScopedCrticalSection).

Implements stk::ISyncObject.

Definition at line 252 of file stk_helper.h.

    {
        ISyncObject::AddWaitObject(m_wait_list, wobj);
    }

References stk::ISyncObject::AddWaitObject(), and m_wait_list.

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FindWeightHigherThan()

Weight stk::ISyncObject::FindWeightHigherThan ( Weight comp ) const

inlineinherited

Find higher weight within linked wait objects.

Implementation of ISyncObject::Tick, see ISyncObject. Placed here as it depends on GetUserTaskFromTid.

Parameters

[in]

comp

Weight to compare with.

Returns

Higher weight value than comp, or NO_WEIGHT if there is no object with a higher weight.

Note

Must be called inside the critical section (see hw::CriticalSection, sync::ScopedCrticalSection).

Definition at line 333 of file stk_helper.h.

{
    Weight max_weight = NO_WEIGHT;
    const IWaitObject *itr = util::DListCast::ListEntryToParent<const IWaitObject>(GetWaitList().GetFirst());
 
    while (itr != nullptr)
    {
        const Weight w = GetUserTaskFromTid(itr->GetTid())->GetWeight();
        if (w > max_weight)
        {
            max_weight = w;
        }
            
        itr = util::DListCast::ListEntryToParent<const IWaitObject>(itr->GetNext());
    }
 
    return ((max_weight > comp) ? max_weight : NO_WEIGHT);
}

References stk::util::DListEntry< T, TClosedLoop >::GetNext(), stk::IWaitObject::GetTid(), stk::GetUserTaskFromTid(), GetWaitList(), stk::ITask::GetWeight(), stk::util::DListCast::ListEntryToParent(), and stk::NO_WEIGHT.

Referenced by stk::Kernel< stk::KERNEL_DYNAMIC|stk::KERNEL_SYNC|stk::KERNEL_TICKLESS,(16U), stk::SwitchStrategyFP32, stk::PlatformDefault >::OnRestoreWeight(), and stk::sync::Mutex::Unlock().

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GetHead()

DLHeadType * stk::util::DListEntry< ISyncObject, TClosedLoop >::GetHead ( )

inlineinherited

Get the list head this entry currently belongs to.

Returns

Pointer to the owning DListHead, or NULL if the entry is not linked.

Definition at line 85 of file stk_linked_list.h.

{ return m_head; }

GetNext()

DLEntryType * stk::util::DListEntry< ISyncObject, TClosedLoop >::GetNext ( )

inlineinherited

Get the next entry in the list.

Returns

Pointer to the next DListEntry, or NULL if this is the last entry (open list) or the first entry (closed loop, where next wraps to first).

Note

In a closed loop (TClosedLoop == true) this pointer is never NULL when the entry is linked.

Definition at line 98 of file stk_linked_list.h.

{ return m_next; }

GetPrev()

DLEntryType * stk::util::DListEntry< ISyncObject, TClosedLoop >::GetPrev ( )

inlineinherited

Get the previous entry in the list.

Returns

Pointer to the previous DListEntry, or NULL if this is the first entry (open list) or the last entry (closed loop, where prev wraps to last).

Note

In a closed loop (TClosedLoop == true) this pointer is never NULL when the entry is linked.

Definition at line 114 of file stk_linked_list.h.

{ return m_prev; }

GetWaitList() [1/2]

const IWaitObject::ListHeadType & stk::SyncObjectBase::GetWaitList ( ) const

inlineoverridevirtual

Get list of tasks blocked on this object.

Note

Read-only access for diagnostics / telemetry.

Implements stk::ISyncObject.

Definition at line 262 of file stk_helper.h.

    {
        return m_wait_list;
    }

References m_wait_list.

GetWaitList() [2/2]

IWaitObject::ListHeadType & stk::SyncObjectBase::GetWaitList ( )

inlineoverrideprotectedvirtual

Get list of tasks blocked on this object.

Implements stk::ISyncObject.

Definition at line 289 of file stk_helper.h.

    {
        return m_wait_list;
    }

References m_wait_list.

IsLinked()

bool stk::util::DListEntry< ISyncObject, TClosedLoop >::IsLinked ( ) const

inlineinherited

Check whether this entry is currently a member of any list.

Returns

true if linked (m_head != NULL); false otherwise.

Definition at line 127 of file stk_linked_list.h.

{ return (GetHead() != nullptr); }

Link()

void stk::util::DListEntry< ISyncObject, TClosedLoop >::Link ( DLHeadType * head, DLEntryType * next, DLEntryType * prev )

inlineprivateinherited

Wire this entry into a list between prev and next.

Parameters

[in]	head	The owning DListHead. Stored as a back-pointer for IsLinked() and ownership checks.
[in]	next	The entry that will follow this one, or NULL if this becomes the last entry.
[in]	prev	The entry that will precede this one, or NULL if this becomes the first entry.

Note

Called exclusively by DListHead::Link(). Assumes the entry is not currently linked. Updates the neighbours' forward/back pointers to splice this entry in.

Definition at line 162 of file stk_linked_list.h.

    {
        m_head = head;
        m_next = next;
        m_prev = prev;
 
        if (m_prev != nullptr)
        {
            m_prev->m_next = this;
        }
 
        if (m_next != nullptr)
        {
            m_next->m_prev = this;
        }
    }

operator const ISyncObject *()

stk::util::DListEntry< ISyncObject, TClosedLoop >::operator const ISyncObject * ( ) const

inlineinherited

Implicit conversion to a const pointer to the host object (T).

Note

Safe because T must derive from DListEntry<T, TClosedLoop>. Eliminates the need for explicit static_cast at call sites.

MISRA deviation: [STK-DEV-004] Rule 5-2-x.

Definition at line 141 of file stk_linked_list.h.

{ return static_cast<const T *>(this); }

operator ISyncObject *()

stk::util::DListEntry< ISyncObject, TClosedLoop >::operator ISyncObject* ( )

inlineinherited

Implicit conversion to a mutable pointer to the host object (T).

Note

Safe because T must derive from DListEntry<T, TClosedLoop>. Eliminates the need for explicit static_cast at call sites.

MISRA deviation: [STK-DEV-004] Rule 5-2-x.

Definition at line 134 of file stk_linked_list.h.

{ return static_cast<T *>(this); }

RemoveWaitObject() [1/2]

void stk::ISyncObject::RemoveWaitObject ( IWaitObject::ListHeadType & wlist, IWaitObject * wobj )

inlinestaticinherited

Called by kernel when a waiting task is being removed (timeout expired, wait aborted, task terminated etc.).

Parameters

[in]

wobj

Wait object to remove from the wait list.

Note

Utility for AddWaitObject and ARM TrustZone support.

Definition at line 599 of file stk_common.h.

    {
        STK_ASSERT(wobj->GetHead() == &wlist);
        wlist.Unlink(wobj);
    }

References stk::util::DListEntry< T, TClosedLoop >::GetHead(), STK_ASSERT, and stk::util::DListHead< T, TClosedLoop >::Unlink().

Referenced by stk::SyncObjectBase::RemoveWaitObject().

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RemoveWaitObject() [2/2]

void stk::SyncObjectBase::RemoveWaitObject ( IWaitObject * wobj )

inlineoverridevirtual

Called by kernel when a waiting task is being removed (timeout expired, wait aborted, task terminated etc.).

Parameters

[in]

wobj

Wait object to remove from the wait list.

Note

Must be called inside the critical section (see hw::CriticalSection, sync::ScopedCrticalSection).

Implements stk::ISyncObject.

Definition at line 257 of file stk_helper.h.

    {
        ISyncObject::RemoveWaitObject(m_wait_list, wobj);
    }

References m_wait_list, and stk::ISyncObject::RemoveWaitObject().

Referenced by stk::sync::Event::RemoveWaitObject().

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Tick()

bool stk::ISyncObject::Tick ( Timeout elapsed_ticks )

inlinevirtualinherited

Called by kernel on every system tick to handle timeout logic of waiting tasks.

Implementation of ISyncObject::Tick, see ISyncObject. Placed here as it depends on hw namespace.

Parameters

[in]

elapsed_ticks

Number of ticks elapsed between this and previous calls, in case of KERNEL_TICKLESS mode this value can be >1, for non-tickless mode it is always 1.

Returns

true if this synchronization object still has waiters with a finite timeout and requires further tick calls. false if the wait list is empty or all remaining waiters have infinite timeouts, signaling to the kernel that it may stop calling Tick() for this object until a new waiter is added.

Note

When this method returns false, the kernel unlinks this object from its active sync list. It will be re-linked automatically when the next waiter is added via AddWaitObject().

Does not need to be called inside critical section.

Definition at line 298 of file stk_helper.h.

{
    IWaitObject::ListHeadType &wlist = GetWaitList();
 
    // note: ScopedCriticalSection usage
    //
    // Single-core: no critical section needed - Tick() runs inside the
    // SysTick ISR which already executes with interrupts disabled, making
    // re-entrancy impossible on the local core.
    //
    // Multi-core: critical section is required because the tick handler on
    // each core may call Tick() concurrently for the same Semaphore instance,
    // and ISyncObject::Tick() is not re-entrant.
#if (STK_ARCH_CPU_COUNT > 1)
    const hw::CriticalSection::ScopedLock cs_;
#endif
 
    IWaitObject *itr = util::DListCast::ListEntryToParent<IWaitObject>(wlist.GetFirst());
 
    while (itr != nullptr)
    {
        IWaitObject *const next = util::DListCast::ListEntryToParent<IWaitObject>(itr->GetNext());
 
        if (!itr->Tick(elapsed_ticks))
        {
            itr->Wake(true);
        }
 
        itr = next;
    }
 
    return !wlist.IsEmpty();
}

References stk::util::DListHead< T, TClosedLoop >::GetFirst(), stk::util::DListEntry< T, TClosedLoop >::GetNext(), GetWaitList(), stk::util::DListHead< T, TClosedLoop >::IsEmpty(), stk::util::DListCast::ListEntryToParent(), stk::IWaitObject::Tick(), and stk::IWaitObject::Wake().

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Unlink()

void stk::util::DListEntry< ISyncObject, TClosedLoop >::Unlink ( )

inlineprivateinherited

Remove this entry from its current list.

Note

Called exclusively by DListHead::Unlink(). Patches the neighbours' pointers to bridge over this entry, then clears m_head, m_next, and m_prev to NULL so the entry is in a clean unlinked state.

Does not update DListHead::m_count or m_first / m_last — those are the responsibility of the calling DListHead::Unlink().

Definition at line 186 of file stk_linked_list.h.

    {
        if (m_prev != nullptr)
        {
            m_prev->m_next = m_next;
        }
 
        if (m_next != nullptr)
        {
            m_next->m_prev = m_prev;
        }
 
        m_head = nullptr;
        m_next = nullptr;
        m_prev = nullptr;
    }

WakeAll() [1/2]

void stk::ISyncObject::WakeAll ( IWaitObject::ListHeadType & wlist )

inlinestaticinherited

Wake all tasks currently in the wait list.

Note

Each woken task is notified with timeout=false, indicating a successful signal (not a timeout expiry).

Does nothing if no tasks are currently waiting.

Utility for AddWaitObject and ARM TrustZone support.

Definition at line 652 of file stk_common.h.

    {
        while (IWaitObject *const obj = util::DListCast::ListEntryToParent<IWaitObject>(wlist.GetFirst()))
        {
            obj->Wake(false);
        }
    }

References stk::util::DListHead< T, TClosedLoop >::GetFirst(), and stk::util::DListCast::ListEntryToParent().

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WakeAll() [2/2]

void stk::SyncObjectBase::WakeAll ( )

inlineoverrideprotectedvirtual

Wake all tasks currently in the wait list.

Note

Each woken task is notified with timeout=false, indicating a successful signal (not a timeout expiry).

Does nothing if no tasks are currently waiting.

Must be called inside the critical section (see hw::CriticalSection, sync::ScopedCrticalSection).

Implements stk::ISyncObject.

Definition at line 284 of file stk_helper.h.

    {
        IKernelService::GetInstance()->Wake(this, true);
    }

References stk::IKernelService::GetInstance(), and stk::IKernelService::Wake().

Referenced by stk::sync::ConditionVariable::NotifyAll_CS(), stk::sync::Event::Pulse(), and stk::sync::Event::Set().

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WakeOne() [1/2]

void stk::ISyncObject::WakeOne ( IWaitObject::ListHeadType & wlist )

inlinestaticinherited

Wake the first task in the wait list (FIFO order).

Note

The woken task is notified with timeout=false, indicating a successful signal (not a timeout expiry).

Does nothing if no tasks are currently waiting.

Utility for AddWaitObject and ARM TrustZone support.

Definition at line 638 of file stk_common.h.

    {
        if (IWaitObject *const obj = util::DListCast::ListEntryToParent<IWaitObject>(wlist.GetFirst()))
        {
            obj->Wake(false);
        }
    }

References stk::util::DListHead< T, TClosedLoop >::GetFirst(), and stk::util::DListCast::ListEntryToParent().

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WakeOne() [2/2]

void stk::SyncObjectBase::WakeOne ( )

inlineoverrideprotectedvirtual

Wake the first task in the wait list (FIFO order).

Note

The woken task is notified with timeout=false, indicating a successful signal (not a timeout expiry).

Does nothing if no tasks are currently waiting.

Must be called inside the critical section (see hw::CriticalSection, sync::ScopedCrticalSection).

Implements stk::ISyncObject.

Definition at line 279 of file stk_helper.h.

    {
        IKernelService::GetInstance()->Wake(this, false);
    }

References stk::IKernelService::GetInstance(), and stk::IKernelService::Wake().

Referenced by stk::sync::ConditionVariable::NotifyOne_CS(), stk::sync::Event::Pulse(), stk::sync::Event::Set(), and stk::sync::Semaphore::TrySignal().

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Friends And Related Symbol Documentation

IKernelService

friend class IKernelService

friend

Definition at line 249 of file stk_helper.h.

References IKernelService.

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

Member Data Documentation

m_head

DLHeadType* stk::util::DListEntry< ISyncObject, TClosedLoop >::m_head

privateinherited

Owning list head, or NULL when the entry is not linked.

Definition at line 203 of file stk_linked_list.h.

m_next

DLEntryType* stk::util::DListEntry< ISyncObject, TClosedLoop >::m_next

privateinherited

Next entry in the list, or NULL (open list boundary) / first entry (closed loop).

Definition at line 204 of file stk_linked_list.h.

m_prev

DLEntryType* stk::util::DListEntry< ISyncObject, TClosedLoop >::m_prev

privateinherited

Previous entry in the list, or NULL (open list boundary) / last entry (closed loop).

Definition at line 205 of file stk_linked_list.h.

m_wait_list

IWaitObject::ListHeadType stk::SyncObjectBase::m_wait_list

protected

Tasks blocked on this object.

Definition at line 294 of file stk_helper.h.

Referenced by AddWaitObject(), GetWaitList(), GetWaitList(), stk::sync::Event::Pulse(), RemoveWaitObject(), SyncObjectBase(), stk::sync::Semaphore::TrySignal(), stk::sync::Mutex::Unlock(), stk::sync::ConditionVariable::~ConditionVariable(), stk::sync::Event::~Event(), stk::sync::Mutex::~Mutex(), and stk::sync::Semaphore::~Semaphore().

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

• stk_helper.h