Synchronize function comment in MdePkg\Library\BaseLib.h with the instance of this...

[mirror_edk2.git] / MdePkg / Library / BaseLib / Synchronization.c

diff --git a/MdePkg/Library/BaseLib/Synchronization.c b/MdePkg/Library/BaseLib/Synchronization.c
index b7c89732e0f19b5d8daf7f6fa056dafed5e104ca..b84188e61869acdd12aa7f785e38c36350e1dc9d 100644 (file)
--- a/MdePkg/Library/BaseLib/Synchronization.c
+++ b/MdePkg/Library/BaseLib/Synchronization.c
@@ -12,11 +12,6 @@
 \r
 **/\r
 \r
-//\r
-// Include common header file for this module.\r
-//\r
-\r
-\r
 #include "BaseLibInternals.h"\r
 \r
 #define SPIN_LOCK_RELEASED          ((UINTN) 1)\r
@@ -44,7 +39,6 @@ GetSpinLockProperties (
   VOID\r
   )\r
 {\r
-  // @bug May use a PCD entry to determine this alignment.\r
   return 32;\r
 }\r
 \r
@@ -61,7 +55,7 @@ GetSpinLockProperties (
   @param  SpinLock  A pointer to the spin lock to initialize to the released\r
                     state.\r
 \r
-  @return SpinLock\r
+  @return SpinLock in release state.\r
 \r
 **/\r
 SPIN_LOCK *\r
@@ -92,7 +86,7 @@ InitializeSpinLock (
 \r
   @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
 \r
-  @return SpinLock\r
+  @return SpinLock acquired lock.\r
 \r
 **/\r
 SPIN_LOCK *\r
@@ -101,15 +95,32 @@ AcquireSpinLock (
   IN OUT  SPIN_LOCK                 *SpinLock\r
   )\r
 {\r
-  UINT64                            Tick;\r
-  UINT64                            Start, End;\r
-  UINT64                            Timeout;\r
+  UINT64  Current;\r
+  UINT64  Previous;\r
+  UINT64  Total;\r
+  UINT64  Start;\r
+  UINT64  End;\r
+  UINT64  Timeout;\r
+  INT64   Cycle;\r
+  INT64   Delta;\r
 \r
-  Tick = 0;\r
-  Start = 0;\r
-  End = 0;\r
   if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
-    Tick = GetPerformanceCounter ();\r
+    //\r
+    // Get the current timer value\r
+    //\r
+    Current = GetPerformanceCounter();\r
+\r
+    //\r
+    // Initialize local variables\r
+    //\r
+    Start = 0;\r
+    End   = 0;\r
+    Total = 0;\r
+\r
+    //\r
+    // Retrieve the performance counter properties and compute the number of performance\r
+    // counter ticks required to reach the timeout\r
+    //\r
     Timeout = DivU64x32 (\r
                 MultU64x32 (\r
                   GetPerformanceCounterProperties (&Start, &End),\r
@@ -117,16 +128,30 @@ AcquireSpinLock (
                   ),\r
                 1000000\r
                 );\r
-    if (Start < End) {\r
-      Tick += Timeout;\r
-    } else {\r
-      Tick -= Timeout;\r
+    Cycle = End - Start;\r
+    if (Cycle < 0) {\r
+      Cycle = -Cycle;\r
+    }\r
+    Cycle++;\r
+\r
+    while (!AcquireSpinLockOrFail (SpinLock)) {\r
+      CpuPause ();\r
+      Previous = Current;\r
+      Current  = GetPerformanceCounter();\r
+      Delta = (INT64) (Current - Previous);\r
+      if (Start > End) {\r
+        Delta = -Delta;\r
+      }\r
+      if (Delta < 0) {\r
+        Delta += Cycle;\r
+      }\r
+      Total += Delta;\r
+      ASSERT (Total < Timeout);\r
+    }\r
+  } else {\r
+    while (!AcquireSpinLockOrFail (SpinLock)) {\r
+      CpuPause ();\r
     }\r
-  }\r
-\r
-  while (!AcquireSpinLockOrFail (SpinLock)) {\r
-    CpuPause ();\r
-    ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
   }\r
   return SpinLock;\r
 }\r
@@ -159,7 +184,7 @@ AcquireSpinLockOrFail (
   ASSERT (SpinLock != NULL);\r
 \r
   LockValue = *SpinLock;\r
-  ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
+  ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);\r
 \r
   return (BOOLEAN)(\r
            InterlockedCompareExchangePointer (\r
@@ -181,7 +206,7 @@ AcquireSpinLockOrFail (
 \r
   @param  SpinLock  A pointer to the spin lock to release.\r
 \r
-  @return SpinLock\r
+  @return SpinLock released lock.\r
 \r
 **/\r
 SPIN_LOCK *\r
@@ -195,7 +220,7 @@ ReleaseSpinLock (
   ASSERT (SpinLock != NULL);\r
 \r
   LockValue = *SpinLock;\r
-  ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
+  ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);\r
 \r
   *SpinLock = SPIN_LOCK_RELEASED;\r
   return SpinLock;\r
@@ -255,9 +280,9 @@ InterlockedDecrement (
   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
+  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
+  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
@@ -285,9 +310,9 @@ InterlockedCompareExchange32 (
 /**\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
+  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
@@ -327,6 +352,8 @@ InterlockedCompareExchange64 (
                         operation.\r
   @param  CompareValue  Pointer value used in compare operation.\r
   @param  ExchangeValue Pointer value used in exchange operation.\r
+  \r
+  @return The original *Value before exchange.\r
 \r
 **/\r
 VOID *\r