MdeModulePkg/Library/SmmPerformanceLib/SmmPerformanceLib.c - device/linaro/bootloader/edk2 - Git at Google

 /** @file
   Performance Library used in SMM phase.

   This library instance provides infrastructure for SMM drivers to log performance
   data. It consumes SMM PerformanceEx or Performance Protocol published by SmmCorePerformanceLib
   to log performance data. If both SMM PerformanceEx and Performance Protocol are not available, it does not log any
   performance information.

   Copyright (c) 2011 - 2016, 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 <Guid/Performance.h>

 #include <Library/PerformanceLib.h>
 #include <Library/DebugLib.h>
 #include <Library/SmmServicesTableLib.h>
 #include <Library/PcdLib.h>
 #include <Library/BaseMemoryLib.h>

 //
 // The cached SMM Performance Protocol and SMM PerformanceEx Protocol interface.
 //
 PERFORMANCE_PROTOCOL        *mPerformance = NULL;
 PERFORMANCE_EX_PROTOCOL     *mPerformanceEx = NULL;
 BOOLEAN                     mPerformanceMeasurementEnabled;

 /**
   The constructor function initializes the Performance Measurement Enable flag

   @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 EFI_SUCCESS.

 **/
 EFI_STATUS
 EFIAPI
 SmmPerformanceLibConstructor (
   IN EFI_HANDLE        ImageHandle,
   IN EFI_SYSTEM_TABLE  *SystemTable
   )
 {

   mPerformanceMeasurementEnabled =  (BOOLEAN) ((PcdGet8(PcdPerformanceLibraryPropertyMask) & PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED) != 0);

   return EFI_SUCCESS;
 }

 /**
   The function caches the pointers to SMM PerformanceEx protocol and Performance Protocol.

   The function locates SMM PerformanceEx protocol and Performance Protocol from protocol database.

   @retval EFI_SUCCESS     SMM PerformanceEx protocol or Performance Protocol is successfully located.
   @retval EFI_NOT_FOUND   Both SMM PerformanceEx protocol and Performance Protocol are not located to log performance.

 **/
 EFI_STATUS
 GetPerformanceProtocol (
   VOID
   )
 {
   EFI_STATUS                Status;
   PERFORMANCE_PROTOCOL      *Performance;
   PERFORMANCE_EX_PROTOCOL   *PerformanceEx;

   if (mPerformanceEx != NULL || mPerformance != NULL) {
     return EFI_SUCCESS;
   }

   Status = gSmst->SmmLocateProtocol (&gSmmPerformanceExProtocolGuid, NULL, (VOID **) &PerformanceEx);
   if (!EFI_ERROR (Status)) {
     ASSERT (PerformanceEx != NULL);
     //
     // Cache PerformanceEx Protocol.
     //
     mPerformanceEx = PerformanceEx;
     return EFI_SUCCESS;
   }

   Status = gSmst->SmmLocateProtocol (&gSmmPerformanceProtocolGuid, NULL, (VOID **) &Performance);
   if (!EFI_ERROR (Status)) {
     ASSERT (Performance != NULL);
     //
     // Cache performance protocol.
     //
     mPerformance = Performance;
     return EFI_SUCCESS;
   }

   return EFI_NOT_FOUND;
 }

 /**
   Creates a record for the beginning of a performance measurement.

   Creates a record that contains the Handle, Token, Module and Identifier.
   If TimeStamp is not zero, then TimeStamp is added to the record as the start time.
   If TimeStamp is zero, then this function reads the current time stamp
   and adds that time stamp value to the record as the start time.

   @param  Handle                  Pointer to environment specific context used
                                   to identify the component being measured.
   @param  Token                   Pointer to a Null-terminated ASCII string
                                   that identifies the component being measured.
   @param  Module                  Pointer to a Null-terminated ASCII string
                                   that identifies the module being measured.
   @param  TimeStamp               64-bit time stamp.
   @param  Identifier              32-bit identifier. If the value is 0, the created record
                                   is same as the one created by StartPerformanceMeasurement.

   @retval RETURN_SUCCESS          The start of the measurement was recorded.
   @retval RETURN_OUT_OF_RESOURCES There are not enough resources to record the measurement.

 **/
 RETURN_STATUS
 EFIAPI
 StartPerformanceMeasurementEx (
   IN CONST VOID   *Handle,  OPTIONAL
   IN CONST CHAR8  *Token,   OPTIONAL
   IN CONST CHAR8  *Module,  OPTIONAL
   IN UINT64       TimeStamp,
   IN UINT32       Identifier
   )
 {
   EFI_STATUS  Status;

   Status = GetPerformanceProtocol ();
   if (EFI_ERROR (Status)) {
     return RETURN_OUT_OF_RESOURCES;
   }

   if (mPerformanceEx != NULL) {
     Status = mPerformanceEx->StartGaugeEx (Handle, Token, Module, TimeStamp, Identifier);
   } else if (mPerformance != NULL) {
     Status = mPerformance->StartGauge (Handle, Token, Module, TimeStamp);
   } else {
     ASSERT (FALSE);
   }

   return (RETURN_STATUS) Status;
 }

 /**
   Fills in the end time of a performance measurement.

   Looks up the record that matches Handle, Token and Module.
   If the record can not be found then return RETURN_NOT_FOUND.
   If the record is found and TimeStamp is not zero,
   then TimeStamp is added to the record as the end time.
   If the record is found and TimeStamp is zero, then this function reads
   the current time stamp and adds that time stamp value to the record as the end time.

   @param  Handle                  Pointer to environment specific context used
                                   to identify the component being measured.
   @param  Token                   Pointer to a Null-terminated ASCII string
                                   that identifies the component being measured.
   @param  Module                  Pointer to a Null-terminated ASCII string
                                   that identifies the module being measured.
   @param  TimeStamp               64-bit time stamp.
   @param  Identifier              32-bit identifier. If the value is 0, the found record
                                   is same as the one found by EndPerformanceMeasurement.

   @retval RETURN_SUCCESS          The end of  the measurement was recorded.
   @retval RETURN_NOT_FOUND        The specified measurement record could not be found.

 **/
 RETURN_STATUS
 EFIAPI
 EndPerformanceMeasurementEx (
   IN CONST VOID   *Handle,  OPTIONAL
   IN CONST CHAR8  *Token,   OPTIONAL
   IN CONST CHAR8  *Module,  OPTIONAL
   IN UINT64       TimeStamp,
   IN UINT32       Identifier
   )
 {
   EFI_STATUS  Status;

   Status = GetPerformanceProtocol ();
   if (EFI_ERROR (Status)) {
     return RETURN_NOT_FOUND;
   }

   if (mPerformanceEx != NULL) {
     Status = mPerformanceEx->EndGaugeEx (Handle, Token, Module, TimeStamp, Identifier);
   } else if (mPerformance != NULL) {
     Status = mPerformance->EndGauge (Handle, Token, Module, TimeStamp);
   } else {
     ASSERT (FALSE);
   }

   return (RETURN_STATUS) Status;
 }

 /**
   Attempts to retrieve a performance measurement log entry from the performance measurement log.
   It can also retrieve the log created by StartPerformanceMeasurement and EndPerformanceMeasurement,
   and then assign the Identifier with 0.

   Attempts to retrieve the performance log entry specified by LogEntryKey.  If LogEntryKey is
   zero on entry, then an attempt is made to retrieve the first entry from the performance log,
   and the key for the second entry in the log is returned.  If the performance log is empty,
   then no entry is retrieved and zero is returned.  If LogEntryKey is not zero, then the performance
   log entry associated with LogEntryKey is retrieved, and the key for the next entry in the log is
   returned.  If LogEntryKey is the key for the last entry in the log, then the last log entry is
   retrieved and an implementation specific non-zero key value that specifies the end of the performance
   log is returned.  If LogEntryKey is equal this implementation specific non-zero key value, then no entry
   is retrieved and zero is returned.  In the cases where a performance log entry can be returned,
   the log entry is returned in Handle, Token, Module, StartTimeStamp, EndTimeStamp and Identifier.
   If LogEntryKey is not a valid log entry key for the performance measurement log, then ASSERT().
   If Handle is NULL, then ASSERT().
   If Token is NULL, then ASSERT().
   If Module is NULL, then ASSERT().
   If StartTimeStamp is NULL, then ASSERT().
   If EndTimeStamp is NULL, then ASSERT().
   If Identifier is NULL, then ASSERT().

   @param  LogEntryKey             On entry, the key of the performance measurement log entry to retrieve.
                                   0, then the first performance measurement log entry is retrieved.
                                   On exit, the key of the next performance log entry.
   @param  Handle                  Pointer to environment specific context used to identify the component
                                   being measured.
   @param  Token                   Pointer to a Null-terminated ASCII string that identifies the component
                                   being measured.
   @param  Module                  Pointer to a Null-terminated ASCII string that identifies the module
                                   being measured.
   @param  StartTimeStamp          Pointer to the 64-bit time stamp that was recorded when the measurement
                                   was started.
   @param  EndTimeStamp            Pointer to the 64-bit time stamp that was recorded when the measurement
                                   was ended.
   @param  Identifier              Pointer to the 32-bit identifier that was recorded.

   @return The key for the next performance log entry (in general case).

 **/
 UINTN
 EFIAPI
 GetPerformanceMeasurementEx (
   IN  UINTN       LogEntryKey,
   OUT CONST VOID  **Handle,
   OUT CONST CHAR8 **Token,
   OUT CONST CHAR8 **Module,
   OUT UINT64      *StartTimeStamp,
   OUT UINT64      *EndTimeStamp,
   OUT UINT32      *Identifier
   )
 {
   EFI_STATUS            Status;
   GAUGE_DATA_ENTRY_EX   *GaugeData;

   GaugeData = NULL;

   ASSERT (Handle != NULL);
   ASSERT (Token != NULL);
   ASSERT (Module != NULL);
   ASSERT (StartTimeStamp != NULL);
   ASSERT (EndTimeStamp != NULL);
   ASSERT (Identifier != NULL);

   Status = GetPerformanceProtocol ();
   if (EFI_ERROR (Status)) {
     return 0;
   }

   if (mPerformanceEx != NULL) {
     Status = mPerformanceEx->GetGaugeEx (LogEntryKey++, &GaugeData);
   } else if (mPerformance != NULL) {
     Status = mPerformance->GetGauge (LogEntryKey++, (GAUGE_DATA_ENTRY **) &GaugeData);
   } else {
     ASSERT (FALSE);
     return 0;
   }

   //
   // Make sure that LogEntryKey is a valid log entry key,
   //
   ASSERT (Status != EFI_INVALID_PARAMETER);

   if (EFI_ERROR (Status)) {
     //
     // The LogEntryKey is the last entry (equals to the total entry number).
     //
     return 0;
   }

   ASSERT (GaugeData != NULL);

   *Handle         = (VOID *) (UINTN) GaugeData->Handle;
   *Token          = GaugeData->Token;
   *Module         = GaugeData->Module;
   *StartTimeStamp = GaugeData->StartTimeStamp;
   *EndTimeStamp   = GaugeData->EndTimeStamp;
   if (mPerformanceEx != NULL) {
     *Identifier   = GaugeData->Identifier;
   } else {
     *Identifier   = 0;
   }

   return LogEntryKey;
 }

 /**
   Creates a record for the beginning of a performance measurement.

   Creates a record that contains the Handle, Token, and Module.
   If TimeStamp is not zero, then TimeStamp is added to the record as the start time.
   If TimeStamp is zero, then this function reads the current time stamp
   and adds that time stamp value to the record as the start time.

   @param  Handle                  Pointer to environment specific context used
                                   to identify the component being measured.
   @param  Token                   Pointer to a Null-terminated ASCII string
                                   that identifies the component being measured.
   @param  Module                  Pointer to a Null-terminated ASCII string
                                   that identifies the module being measured.
   @param  TimeStamp               64-bit time stamp.

   @retval RETURN_SUCCESS          The start of the measurement was recorded.
   @retval RETURN_OUT_OF_RESOURCES There are not enough resources to record the measurement.

 **/
 RETURN_STATUS
 EFIAPI
 StartPerformanceMeasurement (
   IN CONST VOID   *Handle,  OPTIONAL
   IN CONST CHAR8  *Token,   OPTIONAL
   IN CONST CHAR8  *Module,  OPTIONAL
   IN UINT64       TimeStamp
   )
 {
   return StartPerformanceMeasurementEx (Handle, Token, Module, TimeStamp, 0);
 }

 /**
   Fills in the end time of a performance measurement.

   Looks up the record that matches Handle, Token, and Module.
   If the record can not be found then return RETURN_NOT_FOUND.
   If the record is found and TimeStamp is not zero,
   then TimeStamp is added to the record as the end time.
   If the record is found and TimeStamp is zero, then this function reads
   the current time stamp and adds that time stamp value to the record as the end time.

   @param  Handle                  Pointer to environment specific context used
                                   to identify the component being measured.
   @param  Token                   Pointer to a Null-terminated ASCII string
                                   that identifies the component being measured.
   @param  Module                  Pointer to a Null-terminated ASCII string
                                   that identifies the module being measured.
   @param  TimeStamp               64-bit time stamp.

   @retval RETURN_SUCCESS          The end of  the measurement was recorded.
   @retval RETURN_NOT_FOUND        The specified measurement record could not be found.

 **/
 RETURN_STATUS
 EFIAPI
 EndPerformanceMeasurement (
   IN CONST VOID   *Handle,  OPTIONAL
   IN CONST CHAR8  *Token,   OPTIONAL
   IN CONST CHAR8  *Module,  OPTIONAL
   IN UINT64       TimeStamp
   )
 {
   return EndPerformanceMeasurementEx (Handle, Token, Module, TimeStamp, 0);
 }

 /**
   Attempts to retrieve a performance measurement log entry from the performance measurement log.
   It can also retrieve the log created by StartPerformanceMeasurementEx and EndPerformanceMeasurementEx,
   and then eliminate the Identifier.

   Attempts to retrieve the performance log entry specified by LogEntryKey.  If LogEntryKey is
   zero on entry, then an attempt is made to retrieve the first entry from the performance log,
   and the key for the second entry in the log is returned.  If the performance log is empty,
   then no entry is retrieved and zero is returned.  If LogEntryKey is not zero, then the performance
   log entry associated with LogEntryKey is retrieved, and the key for the next entry in the log is
   returned.  If LogEntryKey is the key for the last entry in the log, then the last log entry is
   retrieved and an implementation specific non-zero key value that specifies the end of the performance
   log is returned.  If LogEntryKey is equal this implementation specific non-zero key value, then no entry
   is retrieved and zero is returned.  In the cases where a performance log entry can be returned,
   the log entry is returned in Handle, Token, Module, StartTimeStamp, and EndTimeStamp.
   If LogEntryKey is not a valid log entry key for the performance measurement log, then ASSERT().
   If Handle is NULL, then ASSERT().
   If Token is NULL, then ASSERT().
   If Module is NULL, then ASSERT().
   If StartTimeStamp is NULL, then ASSERT().
   If EndTimeStamp is NULL, then ASSERT().

   @param  LogEntryKey             On entry, the key of the performance measurement log entry to retrieve.
                                   0, then the first performance measurement log entry is retrieved.
                                   On exit, the key of the next performance log entry.
   @param  Handle                  Pointer to environment specific context used to identify the component
                                   being measured.
   @param  Token                   Pointer to a Null-terminated ASCII string that identifies the component
                                   being measured.
   @param  Module                  Pointer to a Null-terminated ASCII string that identifies the module
                                   being measured.
   @param  StartTimeStamp          Pointer to the 64-bit time stamp that was recorded when the measurement
                                   was started.
   @param  EndTimeStamp            Pointer to the 64-bit time stamp that was recorded when the measurement
                                   was ended.

   @return The key for the next performance log entry (in general case).

 **/
 UINTN
 EFIAPI
 GetPerformanceMeasurement (
   IN  UINTN       LogEntryKey,
   OUT CONST VOID  **Handle,
   OUT CONST CHAR8 **Token,
   OUT CONST CHAR8 **Module,
   OUT UINT64      *StartTimeStamp,
   OUT UINT64      *EndTimeStamp
   )
 {
   UINT32 Identifier;
   return GetPerformanceMeasurementEx (LogEntryKey, Handle, Token, Module, StartTimeStamp, EndTimeStamp, &Identifier);
 }

 /**
   Returns TRUE if the performance measurement macros are enabled.

   This function returns TRUE if the PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED bit of
   PcdPerformanceLibraryPropertyMask is set.  Otherwise FALSE is returned.

   @retval TRUE                    The PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED bit of
                                   PcdPerformanceLibraryPropertyMask is set.
   @retval FALSE                   The PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED bit of
                                   PcdPerformanceLibraryPropertyMask is clear.

 **/
 BOOLEAN
 EFIAPI
 PerformanceMeasurementEnabled (
   VOID
   )
 {
   return mPerformanceMeasurementEnabled;
 }
	/** @file
	Performance Library used in SMM phase.

	This library instance provides infrastructure for SMM drivers to log performance
	data. It consumes SMM PerformanceEx or Performance Protocol published by SmmCorePerformanceLib
	to log performance data. If both SMM PerformanceEx and Performance Protocol are not available, it does not log any
	performance information.

	Copyright (c) 2011 - 2016, 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 <Guid/Performance.h>

	#include <Library/PerformanceLib.h>
	#include <Library/DebugLib.h>
	#include <Library/SmmServicesTableLib.h>
	#include <Library/PcdLib.h>
	#include <Library/BaseMemoryLib.h>

	//
	// The cached SMM Performance Protocol and SMM PerformanceEx Protocol interface.
	//
	PERFORMANCE_PROTOCOL *mPerformance = NULL;
	PERFORMANCE_EX_PROTOCOL *mPerformanceEx = NULL;
	BOOLEAN mPerformanceMeasurementEnabled;

	/**
	The constructor function initializes the Performance Measurement Enable flag

	@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 EFI_SUCCESS.

	**/
	EFI_STATUS
	EFIAPI
	SmmPerformanceLibConstructor (
	IN EFI_HANDLE ImageHandle,
	IN EFI_SYSTEM_TABLE *SystemTable
	)
	{

	mPerformanceMeasurementEnabled = (BOOLEAN) ((PcdGet8(PcdPerformanceLibraryPropertyMask) & PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED) != 0);

	return EFI_SUCCESS;
	}

	/**
	The function caches the pointers to SMM PerformanceEx protocol and Performance Protocol.

	The function locates SMM PerformanceEx protocol and Performance Protocol from protocol database.

	@retval EFI_SUCCESS SMM PerformanceEx protocol or Performance Protocol is successfully located.
	@retval EFI_NOT_FOUND Both SMM PerformanceEx protocol and Performance Protocol are not located to log performance.

	**/
	EFI_STATUS
	GetPerformanceProtocol (
	VOID
	)
	{
	EFI_STATUS Status;
	PERFORMANCE_PROTOCOL *Performance;
	PERFORMANCE_EX_PROTOCOL *PerformanceEx;

	if (mPerformanceEx != NULL \|\| mPerformance != NULL) {
	return EFI_SUCCESS;
	}

	Status = gSmst->SmmLocateProtocol (&gSmmPerformanceExProtocolGuid, NULL, (VOID **) &PerformanceEx);
	if (!EFI_ERROR (Status)) {
	ASSERT (PerformanceEx != NULL);
	//
	// Cache PerformanceEx Protocol.
	//
	mPerformanceEx = PerformanceEx;
	return EFI_SUCCESS;
	}

	Status = gSmst->SmmLocateProtocol (&gSmmPerformanceProtocolGuid, NULL, (VOID **) &Performance);
	if (!EFI_ERROR (Status)) {
	ASSERT (Performance != NULL);
	//
	// Cache performance protocol.
	//
	mPerformance = Performance;
	return EFI_SUCCESS;
	}

	return EFI_NOT_FOUND;
	}

	/**
	Creates a record for the beginning of a performance measurement.

	Creates a record that contains the Handle, Token, Module and Identifier.
	If TimeStamp is not zero, then TimeStamp is added to the record as the start time.
	If TimeStamp is zero, then this function reads the current time stamp
	and adds that time stamp value to the record as the start time.

	@param Handle Pointer to environment specific context used
	to identify the component being measured.
	@param Token Pointer to a Null-terminated ASCII string
	that identifies the component being measured.
	@param Module Pointer to a Null-terminated ASCII string
	that identifies the module being measured.
	@param TimeStamp 64-bit time stamp.
	@param Identifier 32-bit identifier. If the value is 0, the created record
	is same as the one created by StartPerformanceMeasurement.

	@retval RETURN_SUCCESS The start of the measurement was recorded.
	@retval RETURN_OUT_OF_RESOURCES There are not enough resources to record the measurement.

	**/
	RETURN_STATUS
	EFIAPI
	StartPerformanceMeasurementEx (
	IN CONST VOID *Handle, OPTIONAL
	IN CONST CHAR8 *Token, OPTIONAL
	IN CONST CHAR8 *Module, OPTIONAL
	IN UINT64 TimeStamp,
	IN UINT32 Identifier
	)
	{
	EFI_STATUS Status;

	Status = GetPerformanceProtocol ();
	if (EFI_ERROR (Status)) {
	return RETURN_OUT_OF_RESOURCES;
	}

	if (mPerformanceEx != NULL) {
	Status = mPerformanceEx->StartGaugeEx (Handle, Token, Module, TimeStamp, Identifier);
	} else if (mPerformance != NULL) {
	Status = mPerformance->StartGauge (Handle, Token, Module, TimeStamp);
	} else {
	ASSERT (FALSE);
	}

	return (RETURN_STATUS) Status;
	}

	/**
	Fills in the end time of a performance measurement.

	Looks up the record that matches Handle, Token and Module.
	If the record can not be found then return RETURN_NOT_FOUND.
	If the record is found and TimeStamp is not zero,
	then TimeStamp is added to the record as the end time.
	If the record is found and TimeStamp is zero, then this function reads
	the current time stamp and adds that time stamp value to the record as the end time.

	@param Handle Pointer to environment specific context used
	to identify the component being measured.
	@param Token Pointer to a Null-terminated ASCII string
	that identifies the component being measured.
	@param Module Pointer to a Null-terminated ASCII string
	that identifies the module being measured.
	@param TimeStamp 64-bit time stamp.
	@param Identifier 32-bit identifier. If the value is 0, the found record
	is same as the one found by EndPerformanceMeasurement.

	@retval RETURN_SUCCESS The end of the measurement was recorded.
	@retval RETURN_NOT_FOUND The specified measurement record could not be found.

	**/
	RETURN_STATUS
	EFIAPI
	EndPerformanceMeasurementEx (
	IN CONST VOID *Handle, OPTIONAL
	IN CONST CHAR8 *Token, OPTIONAL
	IN CONST CHAR8 *Module, OPTIONAL
	IN UINT64 TimeStamp,
	IN UINT32 Identifier
	)
	{
	EFI_STATUS Status;

	Status = GetPerformanceProtocol ();
	if (EFI_ERROR (Status)) {
	return RETURN_NOT_FOUND;
	}

	if (mPerformanceEx != NULL) {
	Status = mPerformanceEx->EndGaugeEx (Handle, Token, Module, TimeStamp, Identifier);
	} else if (mPerformance != NULL) {
	Status = mPerformance->EndGauge (Handle, Token, Module, TimeStamp);
	} else {
	ASSERT (FALSE);
	}

	return (RETURN_STATUS) Status;
	}

	/**
	Attempts to retrieve a performance measurement log entry from the performance measurement log.
	It can also retrieve the log created by StartPerformanceMeasurement and EndPerformanceMeasurement,
	and then assign the Identifier with 0.

	Attempts to retrieve the performance log entry specified by LogEntryKey. If LogEntryKey is
	zero on entry, then an attempt is made to retrieve the first entry from the performance log,
	and the key for the second entry in the log is returned. If the performance log is empty,
	then no entry is retrieved and zero is returned. If LogEntryKey is not zero, then the performance
	log entry associated with LogEntryKey is retrieved, and the key for the next entry in the log is
	returned. If LogEntryKey is the key for the last entry in the log, then the last log entry is
	retrieved and an implementation specific non-zero key value that specifies the end of the performance
	log is returned. If LogEntryKey is equal this implementation specific non-zero key value, then no entry
	is retrieved and zero is returned. In the cases where a performance log entry can be returned,
	the log entry is returned in Handle, Token, Module, StartTimeStamp, EndTimeStamp and Identifier.
	If LogEntryKey is not a valid log entry key for the performance measurement log, then ASSERT().
	If Handle is NULL, then ASSERT().
	If Token is NULL, then ASSERT().
	If Module is NULL, then ASSERT().
	If StartTimeStamp is NULL, then ASSERT().
	If EndTimeStamp is NULL, then ASSERT().
	If Identifier is NULL, then ASSERT().

	@param LogEntryKey On entry, the key of the performance measurement log entry to retrieve.
	0, then the first performance measurement log entry is retrieved.
	On exit, the key of the next performance log entry.
	@param Handle Pointer to environment specific context used to identify the component
	being measured.
	@param Token Pointer to a Null-terminated ASCII string that identifies the component
	being measured.
	@param Module Pointer to a Null-terminated ASCII string that identifies the module
	being measured.
	@param StartTimeStamp Pointer to the 64-bit time stamp that was recorded when the measurement
	was started.
	@param EndTimeStamp Pointer to the 64-bit time stamp that was recorded when the measurement
	was ended.
	@param Identifier Pointer to the 32-bit identifier that was recorded.

	@return The key for the next performance log entry (in general case).

	**/
	UINTN
	EFIAPI
	GetPerformanceMeasurementEx (
	IN UINTN LogEntryKey,
	OUT CONST VOID **Handle,
	OUT CONST CHAR8 **Token,
	OUT CONST CHAR8 **Module,
	OUT UINT64 *StartTimeStamp,
	OUT UINT64 *EndTimeStamp,
	OUT UINT32 *Identifier
	)
	{
	EFI_STATUS Status;
	GAUGE_DATA_ENTRY_EX *GaugeData;

	GaugeData = NULL;

	ASSERT (Handle != NULL);
	ASSERT (Token != NULL);
	ASSERT (Module != NULL);
	ASSERT (StartTimeStamp != NULL);
	ASSERT (EndTimeStamp != NULL);
	ASSERT (Identifier != NULL);

	Status = GetPerformanceProtocol ();
	if (EFI_ERROR (Status)) {
	return 0;
	}

	if (mPerformanceEx != NULL) {
	Status = mPerformanceEx->GetGaugeEx (LogEntryKey++, &GaugeData);
	} else if (mPerformance != NULL) {
	Status = mPerformance->GetGauge (LogEntryKey++, (GAUGE_DATA_ENTRY **) &GaugeData);
	} else {
	ASSERT (FALSE);
	return 0;
	}

	//
	// Make sure that LogEntryKey is a valid log entry key,
	//
	ASSERT (Status != EFI_INVALID_PARAMETER);

	if (EFI_ERROR (Status)) {
	//
	// The LogEntryKey is the last entry (equals to the total entry number).
	//
	return 0;
	}

	ASSERT (GaugeData != NULL);

	Handle = (VOID ) (UINTN) GaugeData->Handle;
	*Token = GaugeData->Token;
	*Module = GaugeData->Module;
	*StartTimeStamp = GaugeData->StartTimeStamp;
	*EndTimeStamp = GaugeData->EndTimeStamp;
	if (mPerformanceEx != NULL) {
	*Identifier = GaugeData->Identifier;
	} else {
	*Identifier = 0;
	}

	return LogEntryKey;
	}

	/**
	Creates a record for the beginning of a performance measurement.

	Creates a record that contains the Handle, Token, and Module.
	If TimeStamp is not zero, then TimeStamp is added to the record as the start time.
	If TimeStamp is zero, then this function reads the current time stamp
	and adds that time stamp value to the record as the start time.

	@param Handle Pointer to environment specific context used
	to identify the component being measured.
	@param Token Pointer to a Null-terminated ASCII string
	that identifies the component being measured.
	@param Module Pointer to a Null-terminated ASCII string
	that identifies the module being measured.
	@param TimeStamp 64-bit time stamp.

	@retval RETURN_SUCCESS The start of the measurement was recorded.
	@retval RETURN_OUT_OF_RESOURCES There are not enough resources to record the measurement.

	**/
	RETURN_STATUS
	EFIAPI
	StartPerformanceMeasurement (
	IN CONST VOID *Handle, OPTIONAL
	IN CONST CHAR8 *Token, OPTIONAL
	IN CONST CHAR8 *Module, OPTIONAL
	IN UINT64 TimeStamp
	)
	{
	return StartPerformanceMeasurementEx (Handle, Token, Module, TimeStamp, 0);
	}

	/**
	Fills in the end time of a performance measurement.

	Looks up the record that matches Handle, Token, and Module.
	If the record can not be found then return RETURN_NOT_FOUND.
	If the record is found and TimeStamp is not zero,
	then TimeStamp is added to the record as the end time.
	If the record is found and TimeStamp is zero, then this function reads
	the current time stamp and adds that time stamp value to the record as the end time.

	@param Handle Pointer to environment specific context used
	to identify the component being measured.
	@param Token Pointer to a Null-terminated ASCII string
	that identifies the component being measured.
	@param Module Pointer to a Null-terminated ASCII string
	that identifies the module being measured.
	@param TimeStamp 64-bit time stamp.

	@retval RETURN_SUCCESS The end of the measurement was recorded.
	@retval RETURN_NOT_FOUND The specified measurement record could not be found.

	**/
	RETURN_STATUS
	EFIAPI
	EndPerformanceMeasurement (
	IN CONST VOID *Handle, OPTIONAL
	IN CONST CHAR8 *Token, OPTIONAL
	IN CONST CHAR8 *Module, OPTIONAL
	IN UINT64 TimeStamp
	)
	{
	return EndPerformanceMeasurementEx (Handle, Token, Module, TimeStamp, 0);
	}

	/**
	Attempts to retrieve a performance measurement log entry from the performance measurement log.
	It can also retrieve the log created by StartPerformanceMeasurementEx and EndPerformanceMeasurementEx,
	and then eliminate the Identifier.

	Attempts to retrieve the performance log entry specified by LogEntryKey. If LogEntryKey is
	zero on entry, then an attempt is made to retrieve the first entry from the performance log,
	and the key for the second entry in the log is returned. If the performance log is empty,
	then no entry is retrieved and zero is returned. If LogEntryKey is not zero, then the performance
	log entry associated with LogEntryKey is retrieved, and the key for the next entry in the log is
	returned. If LogEntryKey is the key for the last entry in the log, then the last log entry is
	retrieved and an implementation specific non-zero key value that specifies the end of the performance
	log is returned. If LogEntryKey is equal this implementation specific non-zero key value, then no entry
	is retrieved and zero is returned. In the cases where a performance log entry can be returned,
	the log entry is returned in Handle, Token, Module, StartTimeStamp, and EndTimeStamp.
	If LogEntryKey is not a valid log entry key for the performance measurement log, then ASSERT().
	If Handle is NULL, then ASSERT().
	If Token is NULL, then ASSERT().
	If Module is NULL, then ASSERT().
	If StartTimeStamp is NULL, then ASSERT().
	If EndTimeStamp is NULL, then ASSERT().

	@param LogEntryKey On entry, the key of the performance measurement log entry to retrieve.
	0, then the first performance measurement log entry is retrieved.
	On exit, the key of the next performance log entry.
	@param Handle Pointer to environment specific context used to identify the component
	being measured.
	@param Token Pointer to a Null-terminated ASCII string that identifies the component
	being measured.
	@param Module Pointer to a Null-terminated ASCII string that identifies the module
	being measured.
	@param StartTimeStamp Pointer to the 64-bit time stamp that was recorded when the measurement
	was started.
	@param EndTimeStamp Pointer to the 64-bit time stamp that was recorded when the measurement
	was ended.

	@return The key for the next performance log entry (in general case).

	**/
	UINTN
	EFIAPI
	GetPerformanceMeasurement (
	IN UINTN LogEntryKey,
	OUT CONST VOID **Handle,
	OUT CONST CHAR8 **Token,
	OUT CONST CHAR8 **Module,
	OUT UINT64 *StartTimeStamp,
	OUT UINT64 *EndTimeStamp
	)
	{
	UINT32 Identifier;
	return GetPerformanceMeasurementEx (LogEntryKey, Handle, Token, Module, StartTimeStamp, EndTimeStamp, &Identifier);
	}

	/**
	Returns TRUE if the performance measurement macros are enabled.

	This function returns TRUE if the PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED bit of
	PcdPerformanceLibraryPropertyMask is set. Otherwise FALSE is returned.

	@retval TRUE The PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED bit of
	PcdPerformanceLibraryPropertyMask is set.
	@retval FALSE The PERFORMANCE_LIBRARY_PROPERTY_MEASUREMENT_ENABLED bit of
	PcdPerformanceLibraryPropertyMask is clear.

	**/
	BOOLEAN
	EFIAPI
	PerformanceMeasurementEnabled (
	VOID
	)
	{
	return mPerformanceMeasurementEnabled;
	}