--- /dev/null
+/** @file\r
+ Implementation of synchronization functions.\r
+\r
+ Copyright (c) 2006, Intel Corporation<BR>\r
+ All rights reserved. This program and the accompanying materials\r
+ are licensed and made available under the terms and conditions of the BSD License\r
+ which accompanies this distribution. The full text of the license may be found at\r
+ http://opensource.org/licenses/bsd-license.php\r
+\r
+ THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+\r
+ Module Name: Synchronization.c\r
+\r
+**/\r
+\r
+#include "BaseLibInternals.h"\r
+\r
+#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
+#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
+\r
+/**\r
+ Retrieves the architecture specific spin lock alignment requirements for\r
+ optimal spin lock performance.\r
+\r
+ This function retrieves the spin lock alignment requirements for optimal\r
+ performance on a given CPU architecture. The spin lock alignment must be a\r
+ power of two and is returned by this function. If there are no alignment\r
+ requirements, then 1 must be returned. The spin lock synchronization\r
+ functions must function correctly if the spin lock size and alignment values\r
+ returned by this function are not used at all. These values are hints to the\r
+ consumers of the spin lock synchronization functions to obtain optimal spin\r
+ lock performance.\r
+\r
+ @return The architecture specific spin lock alignment.\r
+\r
+**/\r
+UINTN\r
+EFIAPI\r
+GetSpinLockProperties (\r
+ VOID\r
+ )\r
+{\r
+ // @bug May use a PCD entry to determine this alignment.\r
+ return 32;\r
+}\r
+\r
+/**\r
+ Initializes a spin lock to the released state and returns the spin lock.\r
+\r
+ This function initializes the spin lock specified by SpinLock to the released\r
+ state, and returns SpinLock. Optimal performance can be achieved by calling\r
+ GetSpinLockProperties() to determine the size and alignment requirements for\r
+ SpinLock.\r
+\r
+ If SpinLock is NULL, then ASSERT().\r
+\r
+ @param SpinLock A pointer to the spin lock to initialize to the released\r
+ state.\r
+\r
+ @return SpinLock\r
+\r
+**/\r
+SPIN_LOCK *\r
+EFIAPI\r
+InitializeSpinLock (\r
+ OUT SPIN_LOCK *SpinLock\r
+ )\r
+{\r
+ ASSERT (SpinLock != NULL);\r
+ *SpinLock = SPIN_LOCK_RELEASED;\r
+ return SpinLock;\r
+}\r
+\r
+/**\r
+ Waits until a spin lock can be placed in the acquired state.\r
+\r
+ This function checks the state of the spin lock specified by SpinLock. If\r
+ SpinLock is in the released state, then this function places SpinLock in the\r
+ acquired state and returns SpinLock. Otherwise, this function waits\r
+ indefinitely for the spin lock to be released, and then places it in the\r
+ acquired state and returns SpinLock. All state transitions of SpinLock must\r
+ be performed using MP safe mechanisms.\r
+\r
+ If SpinLock is NULL, then ASSERT().\r
+ If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
+ If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
+ PcdSpinLockTimeout microseconds, then ASSERT().\r
+\r
+ @param SpinLock A pointer to the spin lock to place in the acquired state.\r
+\r
+ @return SpinLock\r
+\r
+**/\r
+SPIN_LOCK *\r
+EFIAPI\r
+AcquireSpinLock (\r
+ IN OUT SPIN_LOCK *SpinLock\r
+ )\r
+{\r
+ UINT64 Tick;\r
+ UINT64 Start, End;\r
+ UINT64 Timeout;\r
+\r
+ Tick = 0;\r
+ Start = 0;\r
+ End = 0;\r
+ if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
+ Tick = GetPerformanceCounter ();\r
+ Timeout = DivU64x32 (\r
+ MultU64x32 (\r
+ GetPerformanceCounterProperties (&Start, &End),\r
+ PcdGet32 (PcdSpinLockTimeout)\r
+ ),\r
+ 1000000\r
+ );\r
+ if (Start < End) {\r
+ Tick += Timeout;\r
+ } else {\r
+ Tick -= Timeout;\r
+ }\r
+ }\r
+\r
+ while (!AcquireSpinLockOrFail (SpinLock)) {\r
+ CpuPause ();\r
+ ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
+ }\r
+ return SpinLock;\r
+}\r
+\r
+/**\r
+ Attempts to place a spin lock in the acquired state.\r
+\r
+ This function checks the state of the spin lock specified by SpinLock. If\r
+ SpinLock is in the released state, then this function places SpinLock in the\r
+ acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
+ transitions of SpinLock must be performed using MP safe mechanisms.\r
+\r
+ If SpinLock is NULL, then ASSERT().\r
+ If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
+\r
+ @param SpinLock A pointer to the spin lock to place in the acquired state.\r
+\r
+ @retval TRUE SpinLock was placed in the acquired state.\r
+ @retval FALSE SpinLock could not be acquired.\r
+\r
+**/\r
+BOOLEAN\r
+EFIAPI\r
+AcquireSpinLockOrFail (\r
+ IN OUT SPIN_LOCK *SpinLock\r
+ )\r
+{\r
+ SPIN_LOCK LockValue;\r
+\r
+ ASSERT (SpinLock != NULL);\r
+\r
+ LockValue = *SpinLock;\r
+ ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
+\r
+ return (BOOLEAN)(\r
+ InterlockedCompareExchangePointer (\r
+ (VOID**)SpinLock,\r
+ (VOID*)SPIN_LOCK_RELEASED,\r
+ (VOID*)SPIN_LOCK_ACQUIRED\r
+ ) == (VOID*)SPIN_LOCK_RELEASED\r
+ );\r
+}\r
+\r
+/**\r
+ Releases a spin lock.\r
+\r
+ This function places the spin lock specified by SpinLock in the release state\r
+ and returns SpinLock.\r
+\r
+ If SpinLock is NULL, then ASSERT().\r
+ If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
+\r
+ @param SpinLock A pointer to the spin lock to release.\r
+\r
+ @return SpinLock\r
+\r
+**/\r
+SPIN_LOCK *\r
+EFIAPI\r
+ReleaseSpinLock (\r
+ IN OUT SPIN_LOCK *SpinLock\r
+ )\r
+{\r
+ SPIN_LOCK LockValue;\r
+\r
+ ASSERT (SpinLock != NULL);\r
+\r
+ LockValue = *SpinLock;\r
+ ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
+\r
+ *SpinLock = SPIN_LOCK_RELEASED;\r
+ return SpinLock;\r
+}\r
+\r
+/**\r
+ Performs an atomic increment of an 32-bit unsigned integer.\r
+\r
+ Performs an atomic increment of the 32-bit unsigned integer specified by\r
+ Value and returns the incremented value. The increment operation must be\r
+ performed using MP safe mechanisms. The state of the return value is not\r
+ guaranteed to be MP safe.\r
+\r
+ If Value is NULL, then ASSERT().\r
+\r
+ @param Value A pointer to the 32-bit value to increment.\r
+\r
+ @return The incremented value.\r
+\r
+**/\r
+UINT32\r
+EFIAPI\r
+InterlockedIncrement (\r
+ IN UINT32 *Value\r
+ )\r
+{\r
+ ASSERT (Value != NULL);\r
+ return InternalSyncIncrement (Value);\r
+}\r
+\r
+/**\r
+ Performs an atomic decrement of an 32-bit unsigned integer.\r
+\r
+ Performs an atomic decrement of the 32-bit unsigned integer specified by\r
+ Value and returns the decremented value. The decrement operation must be\r
+ performed using MP safe mechanisms. The state of the return value is not\r
+ guaranteed to be MP safe.\r
+\r
+ If Value is NULL, then ASSERT().\r
+\r
+ @param Value A pointer to the 32-bit value to decrement.\r
+\r
+ @return The decremented value.\r
+\r
+**/\r
+UINT32\r
+EFIAPI\r
+InterlockedDecrement (\r
+ IN UINT32 *Value\r
+ )\r
+{\r
+ ASSERT (Value != NULL);\r
+ return InternalSyncDecrement (Value);\r
+}\r
+\r
+/**\r
+ Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
+\r
+ Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
+ specified by Value. If Value is equal to CompareValue, then Value is set to \r
+ ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
+ then Value is returned. The compare exchange operation must be performed using \r
+ MP safe mechanisms.\r
+\r
+ If Value is NULL, then ASSERT().\r
+\r
+ @param Value A pointer to the 32-bit value for the compare exchange\r
+ operation.\r
+ @param CompareValue 32-bit value used in compare operation.\r
+ @param ExchangeValue 32-bit value used in exchange operation.\r
+\r
+ @return The original *Value before exchange.\r
+\r
+**/\r
+UINT32\r
+EFIAPI\r
+InterlockedCompareExchange32 (\r
+ IN OUT UINT32 *Value,\r
+ IN UINT32 CompareValue,\r
+ IN UINT32 ExchangeValue\r
+ )\r
+{\r
+ ASSERT (Value != NULL);\r
+ return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
+}\r
+\r
+/**\r
+ Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
+\r
+ Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
+ by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
+ CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
+ The compare exchange operation must be performed using MP safe mechanisms.\r
+\r
+ If Value is NULL, then ASSERT().\r
+\r
+ @param Value A pointer to the 64-bit value for the compare exchange\r
+ operation.\r
+ @param CompareValue 64-bit value used in compare operation.\r
+ @param ExchangeValue 64-bit value used in exchange operation.\r
+\r
+ @return The original *Value before exchange.\r
+\r
+**/\r
+UINT64\r
+EFIAPI\r
+InterlockedCompareExchange64 (\r
+ IN OUT UINT64 *Value,\r
+ IN UINT64 CompareValue,\r
+ IN UINT64 ExchangeValue\r
+ )\r
+{\r
+ ASSERT (Value != NULL);\r
+ return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
+}\r
+\r
+/**\r
+ Performs an atomic compare exchange operation on a pointer value.\r
+\r
+ Performs an atomic compare exchange operation on the pointer value specified\r
+ by Value. If Value is equal to CompareValue, then Value is set to\r
+ ExchangeValue and CompareValue is returned. If Value is not equal to\r
+ CompareValue, then Value is returned. The compare exchange operation must be\r
+ performed using MP safe mechanisms.\r
+\r
+ If Value is NULL, then ASSERT().\r
+\r
+ @param Value A pointer to the pointer value for the compare exchange\r
+ operation.\r
+ @param CompareValue Pointer value used in compare operation.\r
+ @param ExchangeValue Pointer value used in exchange operation.\r
+\r
+**/\r
+VOID *\r
+EFIAPI\r
+InterlockedCompareExchangePointer (\r
+ IN OUT VOID **Value,\r
+ IN VOID *CompareValue,\r
+ IN VOID *ExchangeValue\r
+ )\r
+{\r
+ UINT8 SizeOfValue;\r
+\r
+ SizeOfValue = sizeof (*Value);\r
+\r
+ switch (SizeOfValue) {\r
+ case sizeof (UINT32):\r
+ return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
+ (UINT32*)Value,\r
+ (UINT32)(UINTN)CompareValue,\r
+ (UINT32)(UINTN)ExchangeValue\r
+ );\r
+ case sizeof (UINT64):\r
+ return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
+ (UINT64*)Value,\r
+ (UINT64)(UINTN)CompareValue,\r
+ (UINT64)(UINTN)ExchangeValue\r
+ );\r
+ default:\r
+ ASSERT (FALSE);\r
+ return NULL;\r
+ }\r
+}\r
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