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

["Dong, Eric" <eric.dong@intel.com>]

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
> 
> 
>