MdePkg/Library/BaseSynchronizationLib/Synchronization.c File Reference


Defines

#define SPIN_LOCK_RELEASED   ((UINTN) 1)
#define SPIN_LOCK_ACQUIRED   ((UINTN) 2)

Functions

UINTN EFIAPI GetSpinLockProperties (VOID)
SPIN_LOCK *EFIAPI InitializeSpinLock (OUT SPIN_LOCK *SpinLock)
SPIN_LOCK *EFIAPI AcquireSpinLock (IN OUT SPIN_LOCK *SpinLock)
BOOLEAN EFIAPI AcquireSpinLockOrFail (IN OUT SPIN_LOCK *SpinLock)
SPIN_LOCK *EFIAPI ReleaseSpinLock (IN OUT SPIN_LOCK *SpinLock)
UINT32 EFIAPI InterlockedIncrement (IN UINT32 *Value)
UINT32 EFIAPI InterlockedDecrement (IN UINT32 *Value)
UINT16 EFIAPI InterlockedCompareExchange16 (IN OUT UINT16 *Value, IN UINT16 CompareValue, IN UINT16 ExchangeValue)
UINT32 EFIAPI InterlockedCompareExchange32 (IN OUT UINT32 *Value, IN UINT32 CompareValue, IN UINT32 ExchangeValue)
UINT64 EFIAPI InterlockedCompareExchange64 (IN OUT UINT64 *Value, IN UINT64 CompareValue, IN UINT64 ExchangeValue)
VOID *EFIAPI InterlockedCompareExchangePointer (IN OUT VOID **Value, IN VOID *CompareValue, IN VOID *ExchangeValue)

Detailed Description

Implementation of synchronization functions.

Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License which accompanies this distribution. The full text of the license may be found at http://opensource.org/licenses/bsd-license.php.

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.


Define Documentation

#define SPIN_LOCK_ACQUIRED   ((UINTN) 2)

#define SPIN_LOCK_RELEASED   ((UINTN) 1)


Function Documentation

SPIN_LOCK* EFIAPI AcquireSpinLock ( IN OUT SPIN_LOCK SpinLock  ) 

Waits until a spin lock can be placed in the acquired state.

This function checks the state of the spin lock specified by SpinLock. If SpinLock is in the released state, then this function places SpinLock in the acquired state and returns SpinLock. Otherwise, this function waits indefinitely for the spin lock to be released, and then places it in the acquired state and returns SpinLock. All state transitions of SpinLock must be performed using MP safe mechanisms.

If SpinLock is NULL, then ASSERT(). If SpinLock was not initialized with InitializeSpinLock(), then ASSERT(). If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in PcdSpinLockTimeout microseconds, then ASSERT().

Parameters:
SpinLock A pointer to the spin lock to place in the acquired state.
Returns:
SpinLock acquired the lock.

References AcquireSpinLockOrFail(), ASSERT, CpuPause(), DivU64x32(), GetPerformanceCounter(), GetPerformanceCounterProperties(), MultU64x32(), and PcdGet32.

BOOLEAN EFIAPI AcquireSpinLockOrFail ( IN OUT SPIN_LOCK SpinLock  ) 

Attempts to place a spin lock in the acquired state.

This function checks the state of the spin lock specified by SpinLock. If SpinLock is in the released state, then this function places SpinLock in the acquired state and returns TRUE. Otherwise, FALSE is returned. All state transitions of SpinLock must be performed using MP safe mechanisms.

If SpinLock is NULL, then ASSERT(). If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().

Parameters:
SpinLock A pointer to the spin lock to place in the acquired state.
Return values:
TRUE SpinLock was placed in the acquired state.
FALSE SpinLock could not be acquired.

References ASSERT, InterlockedCompareExchangePointer(), NULL, SPIN_LOCK_ACQUIRED, SPIN_LOCK_RELEASED, and VOID.

UINTN EFIAPI GetSpinLockProperties ( VOID   ) 

Retrieves the architecture specific spin lock alignment requirements for optimal spin lock performance.

This function retrieves the spin lock alignment requirements for optimal performance on a given CPU architecture. The spin lock alignment is byte alignment. It must be a power of two and is returned by this function. If there are no alignment requirements, then 1 must be returned. The spin lock synchronization functions must function correctly if the spin lock size and alignment values returned by this function are not used at all. These values are hints to the consumers of the spin lock synchronization functions to obtain optimal spin lock performance.

Returns:
The architecture specific spin lock alignment.

SPIN_LOCK* EFIAPI InitializeSpinLock ( OUT SPIN_LOCK SpinLock  ) 

Initializes a spin lock to the released state and returns the spin lock.

This function initializes the spin lock specified by SpinLock to the released state, and returns SpinLock. Optimal performance can be achieved by calling GetSpinLockProperties() to determine the size and alignment requirements for SpinLock.

If SpinLock is NULL, then ASSERT().

Parameters:
SpinLock A pointer to the spin lock to initialize to the released state.
Returns:
SpinLock is in release state.

References ASSERT, NULL, and SPIN_LOCK_RELEASED.

UINT16 EFIAPI InterlockedCompareExchange16 ( IN OUT UINT16 Value,
IN UINT16  CompareValue,
IN UINT16  ExchangeValue 
)

Performs an atomic compare exchange operation on a 16-bit unsigned integer.

Performs an atomic compare exchange operation on the 16-bit unsigned integer specified by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. The compare exchange operation must be performed using MP safe mechanisms.

If Value is NULL, then ASSERT().

Parameters:
Value A pointer to the 16-bit value for the compare exchange operation.
CompareValue 16-bit value used in compare operation.
ExchangeValue 16-bit value used in exchange operation.
Returns:
The original *Value before exchange.

References ASSERT, InternalSyncCompareExchange16(), and NULL.

UINT32 EFIAPI InterlockedCompareExchange32 ( IN OUT UINT32 Value,
IN UINT32  CompareValue,
IN UINT32  ExchangeValue 
)

Performs an atomic compare exchange operation on a 32-bit unsigned integer.

Performs an atomic compare exchange operation on the 32-bit unsigned integer specified by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. The compare exchange operation must be performed using MP safe mechanisms.

If Value is NULL, then ASSERT().

Parameters:
Value A pointer to the 32-bit value for the compare exchange operation.
CompareValue 32-bit value used in compare operation.
ExchangeValue 32-bit value used in exchange operation.
Returns:
The original *Value before exchange.

References ASSERT, InternalSyncCompareExchange32(), and NULL.

UINT64 EFIAPI InterlockedCompareExchange64 ( IN OUT UINT64 Value,
IN UINT64  CompareValue,
IN UINT64  ExchangeValue 
)

Performs an atomic compare exchange operation on a 64-bit unsigned integer.

Performs an atomic compare exchange operation on the 64-bit unsigned integer specified by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. The compare exchange operation must be performed using MP safe mechanisms.

If Value is NULL, then ASSERT().

Parameters:
Value A pointer to the 64-bit value for the compare exchange operation.
CompareValue 64-bit value used in compare operation.
ExchangeValue 64-bit value used in exchange operation.
Returns:
The original *Value before exchange.

References ASSERT, InternalSyncCompareExchange64(), and NULL.

VOID* EFIAPI InterlockedCompareExchangePointer ( IN OUT VOID **  Value,
IN VOID *  CompareValue,
IN VOID *  ExchangeValue 
)

Performs an atomic compare exchange operation on a pointer value.

Performs an atomic compare exchange operation on the pointer value specified by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. The compare exchange operation must be performed using MP safe mechanisms.

If Value is NULL, then ASSERT().

Parameters:
Value A pointer to the pointer value for the compare exchange operation.
CompareValue Pointer value used in compare operation.
ExchangeValue Pointer value used in exchange operation.
Returns:
The original *Value before exchange.

References ASSERT, FALSE, InterlockedCompareExchange32(), InterlockedCompareExchange64(), NULL, and VOID.

UINT32 EFIAPI InterlockedDecrement ( IN UINT32 Value  ) 

Performs an atomic decrement of an 32-bit unsigned integer.

Performs an atomic decrement of the 32-bit unsigned integer specified by Value and returns the decremented value. The decrement operation must be performed using MP safe mechanisms. The state of the return value is not guaranteed to be MP safe.

If Value is NULL, then ASSERT().

Parameters:
Value A pointer to the 32-bit value to decrement.
Returns:
The decremented value.

References ASSERT, InternalSyncDecrement(), and NULL.

UINT32 EFIAPI InterlockedIncrement ( IN UINT32 Value  ) 

Performs an atomic increment of an 32-bit unsigned integer.

Performs an atomic increment of the 32-bit unsigned integer specified by Value and returns the incremented value. The increment operation must be performed using MP safe mechanisms. The state of the return value is not guaranteed to be MP safe.

If Value is NULL, then ASSERT().

Parameters:
Value A pointer to the 32-bit value to increment.
Returns:
The incremented value.

References ASSERT, InternalSyncIncrement(), and NULL.

SPIN_LOCK* EFIAPI ReleaseSpinLock ( IN OUT SPIN_LOCK SpinLock  ) 

Releases a spin lock.

This function places the spin lock specified by SpinLock in the release state and returns SpinLock.

If SpinLock is NULL, then ASSERT(). If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().

Parameters:
SpinLock A pointer to the spin lock to release.
Returns:
SpinLock released lock.

References ASSERT, NULL, SPIN_LOCK_ACQUIRED, and SPIN_LOCK_RELEASED.


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