1 files changed, 116 insertions, 0 deletions
diff --git a/Core/UefiCpuPkg/PiSmmCpuDxeSmm/SyncTimer.c b/Core/UefiCpuPkg/PiSmmCpuDxeSmm/SyncTimer.c
new file mode 100644
index 0000000000..5a632eaa24
--- /dev/null
+++ b/Core/UefiCpuPkg/PiSmmCpuDxeSmm/SyncTimer.c
@@ -0,0 +1,116 @@
+/** @file
+SMM Timer feature support
+
+Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
+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.
+
+**/
+
+#include "PiSmmCpuDxeSmm.h"
+
+UINT64   mTimeoutTicker = 0;
+//
+//  Number of counts in a roll-over cycle of the performance counter.
+//
+UINT64   mCycle = 0;
+//
+// Flag to indicate the performance counter is count-up or count-down.
+//
+BOOLEAN  mCountDown;
+
+/**
+  Initialize Timer for SMM AP Sync.
+
+**/
+VOID
+InitializeSmmTimer (
+  VOID
+  )
+{
+  UINT64  TimerFrequency;
+  UINT64  Start;
+  UINT64  End;
+
+  TimerFrequency = GetPerformanceCounterProperties (&Start, &End);
+  mTimeoutTicker = DivU64x32 (
+                     MultU64x64(TimerFrequency, PcdGet64 (PcdCpuSmmApSyncTimeout)),
+                     1000 * 1000
+                     );
+  if (End < Start) {
+    mCountDown = TRUE;
+    mCycle = Start - End;
+  } else {
+    mCountDown = FALSE;
+    mCycle = End - Start;
+  }
+}
+
+/**
+  Start Timer for SMM AP Sync.
+
+**/
+UINT64
+EFIAPI
+StartSyncTimer (
+  VOID
+  )
+{
+  return GetPerformanceCounter ();
+}
+
+
+/**
+  Check if the SMM AP Sync timer is timeout.
+
+  @param Timer  The start timer from the begin.
+
+**/
+BOOLEAN
+EFIAPI
+IsSyncTimerTimeout (
+  IN      UINT64                    Timer
+  )
+{
+  UINT64  CurrentTimer;
+  UINT64  Delta;
+
+  CurrentTimer = GetPerformanceCounter ();
+  //
+  // We need to consider the case that CurrentTimer is equal to Timer
+  // when some timer runs too slow and CPU runs fast. We think roll over
+  // condition does not happen on this case.
+  //
+  if (mCountDown) {
+    //
+    // The performance counter counts down.  Check for roll over condition.
+    //
+    if (CurrentTimer <= Timer) {
+      Delta = Timer - CurrentTimer;
+    } else {
+      //
+      // Handle one roll-over.
+      //
+      Delta = mCycle - (CurrentTimer - Timer) + 1;
+    }
+  } else {
+    //
+    // The performance counter counts up.  Check for roll over condition.
+    //
+    if (CurrentTimer >= Timer) {
+      Delta = CurrentTimer - Timer;
+    } else {
+      //
+      // Handle one roll-over.
+      //
+      Delta = mCycle - (Timer - CurrentTimer) + 1;
+    }
+  }
+
+  return (BOOLEAN) (Delta >= mTimeoutTicker);
+}