Re: [edk2-devel] [PATCH] UefiCpuPkg: Adding a new TSC library by using CPUID(0x15) TSC leaf

["Liming Gao" <liming.gao@intel.com>]

Donald:
  This change is a new feature. Now, it is not in edk2 feature planning list. If you want to catch it into 201908 stable tag, please get approve from Stewards first. I have cc this mail to all Stewards. 

  For this patch, I have one minor comment. You add one PCD in UefiCpuPkg DEC. Please also add this PCD into UefiCpuPkg.uni. 

Thanks
Liming
> -----Original Message-----
> From: Kuo, Donald
> Sent: Thursday, August 15, 2019 11:02 AM
> To: Dong, Eric <eric.dong@intel.com>; devel@edk2.groups.io; Gao, Liming <liming.gao@intel.com>
> Cc: Ni, Ray <ray.ni@intel.com>; Zeng, Star <star.zeng@intel.com>; Chan, Amy <amy.chan@intel.com>; Chaganty, Rangasai V
> <rangasai.v.chaganty@intel.com>; Lai, Luke <luke.lai@intel.com>; Li, Kevin Y <kevin.y.li@intel.com>
> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg: Adding a new TSC library by using CPUID(0x15) TSC leaf
> 
> Hi Liming,
> 
> As we plan to add new TimerLib to use CPUID Leaf 0x15 (CPU XTAL clock frequency) to calculate TSC to resolve performance value
> unreliable concern.
> 
> As the code review had got approved and planning into 201908 stable tag. Please help to review whether any concern for 201908 stable
> tag.
> 
> Thanks,
> Donald
> 
> > -----Original Message-----
> > From: Dong, Eric
> > Sent: Thursday, August 15, 2019 10:46 AM
> > To: devel@edk2.groups.io; Kuo, Donald <donald.kuo@intel.com>
> > Cc: Ni, Ray <ray.ni@intel.com>; Zeng, Star <star.zeng@intel.com>; Chan,
> > Amy <amy.chan@intel.com>; Chaganty, Rangasai V
> > <rangasai.v.chaganty@intel.com>
> > Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg: Adding a new TSC library by
> > using CPUID(0x15) TSC leaf
> >
> > Reviewed-by: Eric Dong <eric.dong@intel.com>
> >
> > > -----Original Message-----
> > > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of
> > > Donald Kuo
> > > Sent: Tuesday, August 13, 2019 6:53 PM
> > > To: devel@edk2.groups.io
> > > Cc: Ni, Ray <ray.ni@intel.com>; Zeng, Star <star.zeng@intel.com>;
> > > Dong, Eric <eric.dong@intel.com>; Chan, Amy <amy.chan@intel.com>;
> > > Chaganty, Rangasai V <rangasai.v.chaganty@intel.com>
> > > Subject: [edk2-devel] [PATCH] UefiCpuPkg: Adding a new TSC library by
> > > using
> > > CPUID(0x15) TSC leaf
> > >
> > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1909
> > >
> > > Cc: Ray Ni <ray.ni@intel.com>
> > > Cc: Star Zeng <star.zeng@intel.com>
> > > Cc: Eric Dong <eric.dong@intel.com>
> > > Cc: Amy Chan <amy.chan@intel.com>
> > > Cc: Rangasai V Chaganty <rangasai.v.chaganty@intel.com>
> > > Signed-off-by: Donald Kuo <donald.kuo@intel.com>
> > > ---
> > >  UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.c   |  41 +++
> > >  UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.inf |  35 +++
> > > UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.uni |  17 ++
> > >  UefiCpuPkg/Library/CpuTimerLib/CpuTimerLib.c       | 274
> > > +++++++++++++++++++++
> > >  UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c    |  81 ++++++
> > >  UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.inf  |  37 +++
> > > UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.uni  |  17 ++
> > >  UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.c    |  58 +++++
> > >  UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.inf  |  36 +++
> > > UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.uni  |  17 ++
> > >  UefiCpuPkg/UefiCpuPkg.dec                          |   8 +
> > >  UefiCpuPkg/UefiCpuPkg.dsc                          |   3 +
> > >  12 files changed, 624 insertions(+)
> > >  create mode 100644 UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.c
> > >  create mode 100644
> > UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.inf
> > >  create mode 100644
> > UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.uni
> > >  create mode 100644 UefiCpuPkg/Library/CpuTimerLib/CpuTimerLib.c
> > >  create mode 100644 UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c
> > >  create mode 100644 UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.inf
> > >  create mode 100644
> > UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.uni
> > >  create mode 100644 UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.c
> > >  create mode 100644 UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.inf
> > >  create mode 100644 UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.uni
> > >
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.c
> > > b/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.c
> > > new file mode 100644
> > > index 0000000000..6ddf917bad
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.c
> > > @@ -0,0 +1,41 @@
> > > +/** @file
> > > +  CPUID Leaf 0x15 for Core Crystal Clock frequency instance as Base
> > > +Timer
> > > Library.
> > > +
> > > +  Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
> > > +  SPDX-License-Identifier: BSD-2-Clause-Patent
> > > +
> > > +**/
> > > +
> > > +#include <Base.h>
> > > +#include <Library/TimerLib.h>
> > > +#include <Library/BaseLib.h>
> > > +
> > > +/**
> > > +  CPUID Leaf 0x15 for Core Crystal Clock Frequency.
> > > +
> > > +  The TSC counting frequency is determined by using CPUID leaf 0x15.
> > > Frequency in MHz = Core XTAL frequency * EBX/EAX.
> > > +  In newer flavors of the CPU, core xtal frequency is returned in ECX
> > > + or 0 if
> > > not supported.
> > > +  @return The number of TSC counts per second.
> > > +
> > > +**/
> > > +UINT64
> > > +CpuidCoreClockCalculateTscFrequency (
> > > +  VOID
> > > +  );
> > > +
> > > +/**
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  @return The frequency in Hz.
> > > +
> > > +**/
> > > +UINT64
> > > +InternalGetPerformanceCounterFrequency (
> > > +  VOID
> > > +  )
> > > +{
> > > +  return CpuidCoreClockCalculateTscFrequency (); }
> > > +
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.inf
> > > b/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.inf
> > > new file mode 100644
> > > index 0000000000..fd93adc5f1
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.inf
> > > @@ -0,0 +1,35 @@
> > > +## @file
> > > +#  Base CPU Timer Library
> > > +#
> > > +#  Provides basic timer support using CPUID Leaf 0x15 XTAL frequency.
> > > +The performance #  counter features are provided by the processors
> > > +time
> > > stamp counter.
> > > +#
> > > +#  Copyright (c) 2019, Intel Corporation. All rights reserved.<BR> #
> > > +SPDX-License-Identifier: BSD-2-Clause-Patent # ##
> > > +
> > > +[Defines]
> > > +  INF_VERSION                    = 0x00010005
> > > +  BASE_NAME                      = BaseCpuTimerLib
> > > +  FILE_GUID                      = F10B5B91-D15A-496C-B044-B5235721AA08
> > > +  MODULE_TYPE                    = BASE
> > > +  VERSION_STRING                 = 1.0
> > > +  LIBRARY_CLASS                  = TimerLib|SEC PEI_CORE PEIM
> > > +  MODULE_UNI_FILE                = BaseCpuTimerLib.uni
> > > +
> > > +[Sources]
> > > +  CpuTimerLib.c
> > > +  BaseCpuTimerLib.c
> > > +
> > > +[Packages]
> > > +  MdePkg/MdePkg.dec
> > > +  UefiCpuPkg/UefiCpuPkg.dec
> > > +
> > > +[LibraryClasses]
> > > +  BaseLib
> > > +  PcdLib
> > > +  DebugLib
> > > +
> > > +[Pcd]
> > > +  gUefiCpuPkgTokenSpaceGuid.PcdCpuCoreCrystalClockFrequency  ##
> > > +CONSUMES
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.uni
> > > b/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.uni
> > > new file mode 100644
> > > index 0000000000..fcf2b0fbcb
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.uni
> > > @@ -0,0 +1,17 @@
> > > +// /** @file
> > > +// Base CPU Timer Library
> > > +//
> > > +// Provides basic timer support using CPUID Leaf 0x15 XTAL frequency.
> > > +The performance // counter features are provided by the processors
> > > +time
> > > stamp counter.
> > > +//
> > > +// Copyright (c) 2019, Intel Corporation. All rights reserved.<BR> //
> > > +// SPDX-License-Identifier: BSD-2-Clause-Patent // // **/
> > > +
> > > +
> > > +#string STR_MODULE_ABSTRACT             #language en-US "CPU Timer
> > > Library"
> > > +
> > > +#string STR_MODULE_DESCRIPTION          #language en-US "Provides
> > basic
> > > timer support using CPUID Leaf 0x15 XTAL frequency."
> > > +
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/CpuTimerLib.c
> > > b/UefiCpuPkg/Library/CpuTimerLib/CpuTimerLib.c
> > > new file mode 100644
> > > index 0000000000..0b9e9384f5
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/CpuTimerLib.c
> > > @@ -0,0 +1,274 @@
> > > +/** @file
> > > +  CPUID Leaf 0x15 for Core Crystal Clock frequency instance of Timer
> > Library.
> > > +
> > > +  Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
> > > +  SPDX-License-Identifier: BSD-2-Clause-Patent
> > > +
> > > +**/
> > > +
> > > +#include <Base.h>
> > > +#include <Library/TimerLib.h>
> > > +#include <Library/BaseLib.h>
> > > +#include <Library/PcdLib.h>
> > > +#include <Library/DebugLib.h>
> > > +#include <Register/Cpuid.h>
> > > +
> > > +GUID mCpuCrystalFrequencyHobGuid = { 0xe1ec5ad0, 0x8569, 0x46bd, {
> > > +0x8d, 0xcd, 0x3b, 0x9f, 0x6f, 0x45, 0x82, 0x7a } };
> > > +
> > > +/**
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  @return The frequency in Hz.
> > > +
> > > +**/
> > > +UINT64
> > > +InternalGetPerformanceCounterFrequency (
> > > +  VOID
> > > +  );
> > > +
> > > +/**
> > > +  CPUID Leaf 0x15 for Core Crystal Clock Frequency.
> > > +
> > > +  The TSC counting frequency is determined by using CPUID leaf 0x15.
> > > Frequency in MHz = Core XTAL frequency * EBX/EAX.
> > > +  In newer flavors of the CPU, core xtal frequency is returned in ECX
> > > + or 0 if
> > > not supported.
> > > +  @return The number of TSC counts per second.
> > > +
> > > +**/
> > > +UINT64
> > > +CpuidCoreClockCalculateTscFrequency (
> > > +  VOID
> > > +  )
> > > +{
> > > +  UINT64                 TscFrequency;
> > > +  UINT64                 CoreXtalFrequency;
> > > +  UINT32                 RegEax;
> > > +  UINT32                 RegEbx;
> > > +  UINT32                 RegEcx;
> > > +
> > > +  //
> > > +  // Use CPUID leaf 0x15 Time Stamp Counter and Nominal Core Crystal
> > > + Clock Information  // EBX returns 0 if not supported. ECX, if non
> > > + zero,
> > > provides Core Xtal Frequency in hertz.
> > > +  // TSC frequency = (ECX, Core Xtal Frequency) * EBX/EAX.
> > > +  //
> > > +  AsmCpuid (CPUID_TIME_STAMP_COUNTER, &RegEax, &RegEbx,
> > &RegEcx,
> > > NULL);
> > > +
> > > +  //
> > > +  // If EBX returns 0, the XTAL ratio is not enumerated.
> > > +  //
> > > +  ASSERT (RegEbx != 0);
> > > +  //
> > > +  // If ECX returns 0, the XTAL frequency is not enumerated.
> > > +  //
> > > +  if (RegEcx == 0) {
> > > +    CoreXtalFrequency = PcdGet64 (PcdCpuCoreCrystalClockFrequency);
> > > +  } else {
> > > +    CoreXtalFrequency = (UINT64) RegEcx;  }
> > > +
> > > +  //
> > > +  // Calculate TSC frequency = (ECX, Core Xtal Frequency) * EBX/EAX
> > > + // TscFrequency = DivU64x32 (MultU64x32 (CoreXtalFrequency, RegEbx)
> > > + + (UINT64)(RegEax >> 1), RegEax);
> > > +
> > > +  return TscFrequency;
> > > +}
> > > +
> > > +/**
> > > +  Stalls the CPU for at least the given number of ticks.
> > > +
> > > +  Stalls the CPU for at least the given number of ticks. It's invoked
> > > + by
> > > +  MicroSecondDelay() and NanoSecondDelay().
> > > +
> > > +  @param  Delay     A period of time to delay in ticks.
> > > +
> > > +**/
> > > +VOID
> > > +InternalCpuDelay (
> > > +  IN UINT64  Delay
> > > +  )
> > > +{
> > > +  UINT64  Ticks;
> > > +
> > > +  //
> > > +  // The target timer count is calculated here  //  Ticks =
> > > + AsmReadTsc() + Delay;
> > > +
> > > +  //
> > > +  // Wait until time out
> > > +  // Timer wrap-arounds are NOT handled correctly by this function.
> > > +  // Thus, this function must be called within 10 years of reset
> > > +since
> > > +  // Intel guarantees a minimum of 10 years before the TSC wraps.
> > > +  //
> > > +  while (AsmReadTsc() <= Ticks) {
> > > +    CpuPause();
> > > +  }
> > > +}
> > > +
> > > +/**
> > > +  Stalls the CPU for at least the given number of microseconds.
> > > +
> > > +  Stalls the CPU for the number of microseconds specified by
> > MicroSeconds.
> > > +
> > > +  @param[in]  MicroSeconds  The minimum number of microseconds to
> > > delay.
> > > +
> > > +  @return MicroSeconds
> > > +
> > > +**/
> > > +UINTN
> > > +EFIAPI
> > > +MicroSecondDelay (
> > > +  IN UINTN  MicroSeconds
> > > +  )
> > > +{
> > > +
> > > +  InternalCpuDelay (
> > > +    DivU64x32 (
> > > +      MultU64x64 (
> > > +        MicroSeconds,
> > > +        InternalGetPerformanceCounterFrequency ()
> > > +        ),
> > > +      1000000u
> > > +    )
> > > +  );
> > > +
> > > +  return MicroSeconds;
> > > +}
> > > +
> > > +/**
> > > +  Stalls the CPU for at least the given number of nanoseconds.
> > > +
> > > +  Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
> > > +
> > > +  @param  NanoSeconds The minimum number of nanoseconds to delay.
> > > +
> > > +  @return NanoSeconds
> > > +
> > > +**/
> > > +UINTN
> > > +EFIAPI
> > > +NanoSecondDelay (
> > > +  IN UINTN  NanoSeconds
> > > +  )
> > > +{
> > > +
> > > +  InternalCpuDelay (
> > > +    DivU64x32 (
> > > +      MultU64x64 (
> > > +        NanoSeconds,
> > > +        InternalGetPerformanceCounterFrequency ()
> > > +        ),
> > > +      1000000000u
> > > +    )
> > > +  );
> > > +
> > > +  return NanoSeconds;
> > > +}
> > > +
> > > +/**
> > > +  Retrieves the current value of a 64-bit free running performance counter.
> > > +
> > > +  Retrieves the current value of a 64-bit free running performance
> > > + counter. The  counter can either count up by 1 or count down by 1.
> > > + If the physical  performance counter counts by a larger increment,
> > > + then the counter values  must be translated. The properties of the
> > > + counter can be retrieved from  GetPerformanceCounterProperties().
> > > +
> > > +  @return The current value of the free running performance counter.
> > > +
> > > +**/
> > > +UINT64
> > > +EFIAPI
> > > +GetPerformanceCounter (
> > > +  VOID
> > > +  )
> > > +{
> > > +  return AsmReadTsc ();
> > > +}
> > > +
> > > +/**
> > > +  Retrieves the 64-bit frequency in Hz and the range of performance
> > > +counter
> > > +  values.
> > > +
> > > +  If StartValue is not NULL, then the value that the performance
> > > + counter starts  with immediately after is it rolls over is returned
> > > + in StartValue. If  EndValue is not NULL, then the value that the
> > > + performance counter end with  immediately before it rolls over is
> > > + returned in EndValue. The 64-bit  frequency of the performance
> > > + counter in Hz is always returned. If StartValue  is less than
> > > + EndValue, then the performance counter counts up. If StartValue  is
> > > + greater than EndValue, then the performance counter counts down. For
> > > + example, a 64-bit free running counter that counts up would have a
> > > + StartValue  of
> > > + 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running
> > > + counter
> > > that counts down would have a StartValue of 0xFFFFFF and an EndValue of
> > 0.
> > > +
> > > +  @param  StartValue  The value the performance counter starts with
> > > + when
> > > it
> > > +                      rolls over.
> > > +  @param  EndValue    The value that the performance counter ends with
> > > before
> > > +                      it rolls over.
> > > +
> > > +  @return The frequency in Hz.
> > > +
> > > +**/
> > > +UINT64
> > > +EFIAPI
> > > +GetPerformanceCounterProperties (
> > > +  OUT UINT64  *StartValue,  OPTIONAL
> > > +  OUT UINT64  *EndValue     OPTIONAL
> > > +  )
> > > +{
> > > +  if (StartValue != NULL) {
> > > +    *StartValue = 0;
> > > +  }
> > > +
> > > +  if (EndValue != NULL) {
> > > +    *EndValue = 0xffffffffffffffffULL;  }  return
> > > + InternalGetPerformanceCounterFrequency (); }
> > > +
> > > +/**
> > > +  Converts elapsed ticks of performance counter to time in nanoseconds.
> > > +
> > > +  This function converts the elapsed ticks of running performance
> > > + counter to  time value in unit of nanoseconds.
> > > +
> > > +  @param  Ticks     The number of elapsed ticks of running performance
> > > counter.
> > > +
> > > +  @return The elapsed time in nanoseconds.
> > > +
> > > +**/
> > > +UINT64
> > > +EFIAPI
> > > +GetTimeInNanoSecond (
> > > +  IN UINT64  Ticks
> > > +  )
> > > +{
> > > +  UINT64  Frequency;
> > > +  UINT64  NanoSeconds;
> > > +  UINT64  Remainder;
> > > +  INTN    Shift;
> > > +
> > > +  Frequency = GetPerformanceCounterProperties (NULL, NULL);
> > > +
> > > +  //
> > > +  //          Ticks
> > > +  // Time = --------- x 1,000,000,000
> > > +  //        Frequency
> > > +  //
> > > +  NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency,
> > > + &Remainder), 1000000000u);
> > > +
> > > +  //
> > > +  // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
> > > +  // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should
> > > + <
> > > + 2^(64-30) = 2^34,  // i.e. highest bit set in Remainder should <= 33.
> > > +  //
> > > +  Shift = MAX (0, HighBitSet64 (Remainder) - 33);  Remainder =
> > > + RShiftU64 (Remainder, (UINTN) Shift);  Frequency = RShiftU64
> > > + (Frequency, (UINTN) Shift);  NanoSeconds += DivU64x64Remainder
> > > + (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
> > > +
> > > +  return NanoSeconds;
> > > +}
> > > +
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c
> > > b/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c
> > > new file mode 100644
> > > index 0000000000..2d0ef6ab07
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.c
> > > @@ -0,0 +1,81 @@
> > > +/** @file
> > > +  CPUID Leaf 0x15 for Core Crystal Clock frequency instance of Timer
> > Library.
> > > +
> > > +  Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
> > > +  SPDX-License-Identifier: BSD-2-Clause-Patent
> > > +
> > > +**/
> > > +
> > > +#include <PiDxe.h>
> > > +#include <Library/TimerLib.h>
> > > +#include <Library/BaseLib.h>
> > > +#include <Library/HobLib.h>
> > > +
> > > +extern GUID mCpuCrystalFrequencyHobGuid;
> > > +
> > > +/**
> > > +  CPUID Leaf 0x15 for Core Crystal Clock Frequency.
> > > +
> > > +  The TSC counting frequency is determined by using CPUID leaf 0x15.
> > > Frequency in MHz = Core XTAL frequency * EBX/EAX.
> > > +  In newer flavors of the CPU, core xtal frequency is returned in ECX
> > > + or 0 if
> > > not supported.
> > > +  @return The number of TSC counts per second.
> > > +
> > > +**/
> > > +UINT64
> > > +CpuidCoreClockCalculateTscFrequency (
> > > +  VOID
> > > +  );
> > > +
> > > +//
> > > +// Cached CPU Crystal counter frequency //
> > > +UINT64  mCpuCrystalCounterFrequency = 0;
> > > +
> > > +
> > > +/**
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  @return The frequency in Hz.
> > > +
> > > +**/
> > > +UINT64
> > > +InternalGetPerformanceCounterFrequency (
> > > +  VOID
> > > +  )
> > > +{
> > > +  return mCpuCrystalCounterFrequency; }
> > > +
> > > +/**
> > > +  The constructor function is to initialize CpuCrystalCounterFrequency.
> > > +
> > > +  @param  ImageHandle   The firmware allocated handle for the EFI image.
> > > +  @param  SystemTable   A pointer to the EFI System Table.
> > > +
> > > +  @retval EFI_SUCCESS   The constructor always returns
> > RETURN_SUCCESS.
> > > +
> > > +**/
> > > +EFI_STATUS
> > > +EFIAPI
> > > +DxeCpuTimerLibConstructor (
> > > +  IN EFI_HANDLE        ImageHandle,
> > > +  IN EFI_SYSTEM_TABLE  *SystemTable
> > > +  )
> > > +{
> > > +  EFI_HOB_GUID_TYPE   *GuidHob;
> > > +
> > > +  //
> > > +  // Initialize CpuCrystalCounterFrequency  //  GuidHob =
> > > + GetFirstGuidHob (&mCpuCrystalFrequencyHobGuid);  if (GuidHob !=
> > > + NULL) {
> > > +    mCpuCrystalCounterFrequency = *(UINT64*)GET_GUID_HOB_DATA
> > > + (GuidHob);  } else {
> > > +    mCpuCrystalCounterFrequency =
> > CpuidCoreClockCalculateTscFrequency
> > > + ();  }
> > > +
> > > +  return EFI_SUCCESS;
> > > +}
> > > +
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.inf
> > > b/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.inf
> > > new file mode 100644
> > > index 0000000000..6c83549c87
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.inf
> > > @@ -0,0 +1,37 @@
> > > +## @file
> > > +#  DXE CPU Timer Library
> > > +#
> > > +#  Provides basic timer support using CPUID Leaf 0x15 XTAL frequency.
> > > +The performance #  counter features are provided by the processors
> > > +time
> > > stamp counter.
> > > +#
> > > +#  Copyright (c) 2019, Intel Corporation. All rights reserved.<BR> #
> > > +SPDX-License-Identifier: BSD-2-Clause-Patent # ##
> > > +
> > > +[Defines]
> > > +  INF_VERSION                    = 0x00010005
> > > +  BASE_NAME                      = DxeCpuTimerLib
> > > +  FILE_GUID                      = F22CC0DA-E7DB-4E4D-ABE2-A608188233A2
> > > +  MODULE_TYPE                    = DXE_DRIVER
> > > +  VERSION_STRING                 = 1.0
> > > +  LIBRARY_CLASS                  = TimerLib|DXE_CORE DXE_DRIVER
> > > DXE_RUNTIME_DRIVER DXE_SMM_DRIVER UEFI_APPLICATION
> > UEFI_DRIVER
> > > SMM_CORE
> > > +  CONSTRUCTOR                    = DxeCpuTimerLibConstructor
> > > +  MODULE_UNI_FILE                = DxeCpuTimerLib.uni
> > > +
> > > +[Sources]
> > > +  CpuTimerLib.c
> > > +  DxeCpuTimerLib.c
> > > +
> > > +[Packages]
> > > +  MdePkg/MdePkg.dec
> > > +  UefiCpuPkg/UefiCpuPkg.dec
> > > +
> > > +[LibraryClasses]
> > > +  BaseLib
> > > +  PcdLib
> > > +  DebugLib
> > > +  HobLib
> > > +
> > > +[Pcd]
> > > +  gUefiCpuPkgTokenSpaceGuid.PcdCpuCoreCrystalClockFrequency  ##
> > > +CONSUMES
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.uni
> > > b/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.uni
> > > new file mode 100644
> > > index 0000000000..f55b92abac
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.uni
> > > @@ -0,0 +1,17 @@
> > > +// /** @file
> > > +// DXE CPU Timer Library
> > > +//
> > > +// Provides basic timer support using CPUID Leaf 0x15 XTAL frequency.
> > > +The performance // counter features are provided by the processors
> > > +time
> > > stamp counter.
> > > +//
> > > +// Copyright (c) 2019, Intel Corporation. All rights reserved.<BR> //
> > > +// SPDX-License-Identifier: BSD-2-Clause-Patent // // **/
> > > +
> > > +
> > > +#string STR_MODULE_ABSTRACT             #language en-US "CPU Timer
> > > Library"
> > > +
> > > +#string STR_MODULE_DESCRIPTION          #language en-US "Provides
> > basic
> > > timer support using CPUID Leaf 0x15 XTAL frequency."
> > > +
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.c
> > > b/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.c
> > > new file mode 100644
> > > index 0000000000..91a7212056
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.c
> > > @@ -0,0 +1,58 @@
> > > +/** @file
> > > +  CPUID Leaf 0x15 for Core Crystal Clock frequency instance as PEI
> > > +Timer
> > > Library.
> > > +
> > > +  Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
> > > +  SPDX-License-Identifier: BSD-2-Clause-Patent
> > > +
> > > +**/
> > > +
> > > +#include <PiPei.h>
> > > +#include <Library/TimerLib.h>
> > > +#include <Library/BaseLib.h>
> > > +#include <Library/HobLib.h>
> > > +#include <Library/DebugLib.h>
> > > +
> > > +extern GUID mCpuCrystalFrequencyHobGuid;
> > > +
> > > +/**
> > > +  CPUID Leaf 0x15 for Core Crystal Clock Frequency.
> > > +
> > > +  The TSC counting frequency is determined by using CPUID leaf 0x15.
> > > Frequency in MHz = Core XTAL frequency * EBX/EAX.
> > > +  In newer flavors of the CPU, core xtal frequency is returned in ECX
> > > + or 0 if
> > > not supported.
> > > +  @return The number of TSC counts per second.
> > > +
> > > +**/
> > > +UINT64
> > > +CpuidCoreClockCalculateTscFrequency (
> > > +  VOID
> > > +  );
> > > +
> > > +/**
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  Internal function to retrieves the 64-bit frequency in Hz.
> > > +
> > > +  @return The frequency in Hz.
> > > +
> > > +**/
> > > +UINT64
> > > +InternalGetPerformanceCounterFrequency (
> > > +  VOID
> > > +  )
> > > +{
> > > +  UINT64              *CpuCrystalCounterFrequency;
> > > +  EFI_HOB_GUID_TYPE   *GuidHob;
> > > +
> > > +  CpuCrystalCounterFrequency = NULL;
> > > +  GuidHob = GetFirstGuidHob (&mCpuCrystalFrequencyHobGuid);  if
> > > + (GuidHob == NULL) {
> > > +    CpuCrystalCounterFrequency  =
> > > (UINT64*)BuildGuidHob(&mCpuCrystalFrequencyHobGuid, sizeof
> > > (*CpuCrystalCounterFrequency));
> > > +    ASSERT (CpuCrystalCounterFrequency != NULL);
> > > +    *CpuCrystalCounterFrequency = CpuidCoreClockCalculateTscFrequency
> > > + ();  } else {
> > > +    CpuCrystalCounterFrequency = (UINT64*)GET_GUID_HOB_DATA
> > > (GuidHob);
> > > + }
> > > +
> > > +  return  *CpuCrystalCounterFrequency; }
> > > +
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.inf
> > > b/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.inf
> > > new file mode 100644
> > > index 0000000000..7af0fc44a6
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.inf
> > > @@ -0,0 +1,36 @@
> > > +## @file
> > > +#  PEI CPU Timer Library
> > > +#
> > > +#  Provides basic timer support using CPUID Leaf 0x15 XTAL frequency.
> > > +The performance #  counter features are provided by the processors
> > > +time
> > > stamp counter.
> > > +#
> > > +#  Copyright (c) 2019, Intel Corporation. All rights reserved.<BR> #
> > > +SPDX-License-Identifier: BSD-2-Clause-Patent # ##
> > > +
> > > +[Defines]
> > > +  INF_VERSION                    = 0x00010005
> > > +  BASE_NAME                      = PeiCpuTimerLib
> > > +  FILE_GUID                      = 2B13DE00-1A5F-4DD7-A298-01B08AF1015A
> > > +  MODULE_TYPE                    = BASE
> > > +  VERSION_STRING                 = 1.0
> > > +  LIBRARY_CLASS                  = TimerLib|PEI_CORE PEIM
> > > +  MODULE_UNI_FILE                = PeiCpuTimerLib.uni
> > > +
> > > +[Sources]
> > > +  CpuTimerLib.c
> > > +  PeiCpuTimerLib.c
> > > +
> > > +[Packages]
> > > +  MdePkg/MdePkg.dec
> > > +  UefiCpuPkg/UefiCpuPkg.dec
> > > +
> > > +[LibraryClasses]
> > > +  BaseLib
> > > +  PcdLib
> > > +  DebugLib
> > > +  HobLib
> > > +
> > > +[Pcd]
> > > +  gUefiCpuPkgTokenSpaceGuid.PcdCpuCoreCrystalClockFrequency  ##
> > > +CONSUMES
> > > diff --git a/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.uni
> > > b/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.uni
> > > new file mode 100644
> > > index 0000000000..49beb44908
> > > --- /dev/null
> > > +++ b/UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.uni
> > > @@ -0,0 +1,17 @@
> > > +// /** @file
> > > +// PEI CPU Timer Library
> > > +//
> > > +// Provides basic timer support using CPUID Leaf 0x15 XTAL frequency.
> > > +The performance // counter features are provided by the processors
> > > +time
> > > stamp counter.
> > > +//
> > > +// Copyright (c) 2019, Intel Corporation. All rights reserved.<BR> //
> > > +// SPDX-License-Identifier: BSD-2-Clause-Patent // // **/
> > > +
> > > +
> > > +#string STR_MODULE_ABSTRACT             #language en-US "CPU Timer
> > > Library"
> > > +
> > > +#string STR_MODULE_DESCRIPTION          #language en-US "Provides
> > basic
> > > timer support using CPUID Leaf 0x15 XTAL frequency."
> > > +
> > > diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
> > > index 14ddaa8633..a94bd2ea30 100644
> > > --- a/UefiCpuPkg/UefiCpuPkg.dec
> > > +++ b/UefiCpuPkg/UefiCpuPkg.dec
> > > @@ -211,6 +211,14 @@
> > >    # @Prompt If CPU features will be initialized during S3 resume.
> > >
> > > gUefiCpuPkgTokenSpaceGuid.PcdCpuFeaturesInitOnS3Resume|FALSE|BOO
> > > LEAN|0x0000001D
> > >
> > > +  ## Specifies CPUID Leaf 0x15 Time Stamp Counter and Nominal Core
> > > Crystal Clock Frequency.
> > > +  # TSC Frequency = ECX (core crystal clock frequency) * EBX/EAX.
> > > +  #   Intel Xeon Processor Scalable Family with CPUID signature 06_55H =
> > > 25000000 (25MHz)
> > > +  #   6th and 7th generation Intel Core processors and Intel Xeon W
> > > Processor Family = 24000000 (24MHz)
> > > +  #   Intel Atom processors based on Goldmont Microarchitecture with
> > > CPUID signature 06_5CH = 19200000 (19.2MHz)
> > > +  # @Prompt Core Crystal Clock Frequency is for CPUID Leaf 0x15.ECX
> > > +
> > > +
> > >
> > gUefiCpuPkgTokenSpaceGuid.PcdCpuCoreCrystalClockFrequency|24000000|
> > > UIN
> > > + T64|0x32132113
> > > +
> > >  [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
> > >    ## Specifies max supported number of Logical Processors.
> > >    # @Prompt Configure max supported number of Logical Processors diff
> > > --git a/UefiCpuPkg/UefiCpuPkg.dsc b/UefiCpuPkg/UefiCpuPkg.dsc index
> > > bf690d3978..e7dfe30eda 100644
> > > --- a/UefiCpuPkg/UefiCpuPkg.dsc
> > > +++ b/UefiCpuPkg/UefiCpuPkg.dsc
> > > @@ -101,6 +101,9 @@
> > >    UefiCpuPkg/CpuIoPei/CpuIoPei.inf
> > >
> > >
> > UefiCpuPkg/Library/SecPeiDxeTimerLibUefiCpu/SecPeiDxeTimerLibUefiCpu.i
> > > nf
> > >    UefiCpuPkg/Application/Cpuid/Cpuid.inf
> > > +  UefiCpuPkg/Library/CpuTimerLib/BaseCpuTimerLib.inf
> > > +  UefiCpuPkg/Library/CpuTimerLib/DxeCpuTimerLib.inf
> > > +  UefiCpuPkg/Library/CpuTimerLib/PeiCpuTimerLib.inf
> > >
> > >  [Components.IA32, Components.X64]
> > >    UefiCpuPkg/CpuDxe/CpuDxe.inf
> > > --
> > > 2.14.2.windows.3
> > >
> > >
> > >