110 lines
2.1 KiB
C
110 lines
2.1 KiB
C
/** @file
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SMM Timer feature support
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Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include "PiSmmCpuDxeSmm.h"
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UINT64 mTimeoutTicker = 0;
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//
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// Number of counts in a roll-over cycle of the performance counter.
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//
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UINT64 mCycle = 0;
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//
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// Flag to indicate the performance counter is count-up or count-down.
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//
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BOOLEAN mCountDown;
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/**
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Initialize Timer for SMM AP Sync.
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**/
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VOID
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InitializeSmmTimer (
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VOID
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)
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{
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UINT64 TimerFrequency;
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UINT64 Start;
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UINT64 End;
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TimerFrequency = GetPerformanceCounterProperties (&Start, &End);
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mTimeoutTicker = DivU64x32 (
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MultU64x64(TimerFrequency, PcdGet64 (PcdCpuSmmApSyncTimeout)),
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1000 * 1000
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);
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if (End < Start) {
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mCountDown = TRUE;
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mCycle = Start - End;
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} else {
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mCountDown = FALSE;
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mCycle = End - Start;
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}
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}
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/**
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Start Timer for SMM AP Sync.
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**/
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UINT64
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EFIAPI
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StartSyncTimer (
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VOID
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)
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{
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return GetPerformanceCounter ();
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}
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/**
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Check if the SMM AP Sync timer is timeout.
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@param Timer The start timer from the begin.
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**/
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BOOLEAN
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EFIAPI
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IsSyncTimerTimeout (
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IN UINT64 Timer
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)
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{
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UINT64 CurrentTimer;
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UINT64 Delta;
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CurrentTimer = GetPerformanceCounter ();
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//
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// We need to consider the case that CurrentTimer is equal to Timer
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// when some timer runs too slow and CPU runs fast. We think roll over
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// condition does not happen on this case.
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//
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if (mCountDown) {
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//
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// The performance counter counts down. Check for roll over condition.
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//
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if (CurrentTimer <= Timer) {
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Delta = Timer - CurrentTimer;
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} else {
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//
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// Handle one roll-over.
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//
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Delta = mCycle - (CurrentTimer - Timer) + 1;
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}
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} else {
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//
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// The performance counter counts up. Check for roll over condition.
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//
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if (CurrentTimer >= Timer) {
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Delta = CurrentTimer - Timer;
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} else {
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//
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// Handle one roll-over.
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//
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Delta = mCycle - (Timer - CurrentTimer) + 1;
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}
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}
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return (BOOLEAN) (Delta >= mTimeoutTicker);
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}
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