[PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Rebecca Cran]

This is the rework of the patches I sent out in late 2021,
building on fixes done by Ard at
https://github.com/ardbiesheuvel/edk2/tree/armpkg-mpservicesdxe-refactor.

The most significant changes are the addition of code to enable
the MMU and caches on the APs, and changing MpServicesTest to
use commandline parameters to control its operation.

Rebecca Cran (2):
  ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls
  MdeModulePkg: Add new Application/MpServicesTest application

 ArmPkg/ArmPkg.dsc                                            |    1 +
 MdeModulePkg/MdeModulePkg.dsc                                |    9 +
 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf |   55 +
 MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf   |   41 +
 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h     |  351 ++++
 MdeModulePkg/Application/MpServicesTest/Options.h            |   39 +
 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c   | 1774 ++++++++++++++++++++
 MdeModulePkg/Application/MpServicesTest/MpServicesTest.c     |  558 ++++++
 MdeModulePkg/Application/MpServicesTest/Options.c            |  215 +++
 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S                |   57 +
 10 files changed, 3100 insertions(+)
 create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
 create mode 100644 MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf
 create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
 create mode 100644 MdeModulePkg/Application/MpServicesTest/Options.h
 create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
 create mode 100644 MdeModulePkg/Application/MpServicesTest/MpServicesTest.c
 create mode 100644 MdeModulePkg/Application/MpServicesTest/Options.c
 create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S

-- 
2.30.2

[PATCH 1/2] ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls

[Rebecca Cran]

Add support for EFI_MP_SERVICES_PROTOCOL during the DXE phase under
AArch64.

PSCI_CPU_ON is called to power on the core, the supplied procedure is
executed and PSCI_CPU_OFF is called to power off the core.

Fixes contributed by Ard Biesheuvel.

Signed-off-by: Rebecca Cran <rebecca@quicinc.com>
---
 ArmPkg/ArmPkg.dsc                                            |    1 +
 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf |   55 +
 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h     |  351 ++++
 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c   | 1774 ++++++++++++++++++++
 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S                |   57 +
 5 files changed, 2238 insertions(+)

diff --git a/ArmPkg/ArmPkg.dsc b/ArmPkg/ArmPkg.dsc
index 59fd8f295d4f..4716789402fc 100644
--- a/ArmPkg/ArmPkg.dsc
+++ b/ArmPkg/ArmPkg.dsc
@@ -125,6 +125,7 @@ [Components.common]
   ArmPkg/Drivers/CpuPei/CpuPei.inf
   ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
   ArmPkg/Drivers/ArmGic/ArmGicLib.inf
+  ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
   ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.inf
   ArmPkg/Drivers/TimerDxe/TimerDxe.inf
 
diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
new file mode 100644
index 000000000000..2b109c72e0a0
--- /dev/null
+++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
@@ -0,0 +1,55 @@
+## @file
+#  ARM MP services protocol driver
+#
+#  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 1.27
+  BASE_NAME                      = ArmPsciMpServicesDxe
+  FILE_GUID                      = 007ab472-dc4a-4df8-a5c2-abb4a327278c
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+
+  ENTRY_POINT                    = ArmPsciMpServicesDxeInitialize
+
+[Sources.Common]
+  ArmPsciMpServicesDxe.c
+  MpFuncs.S
+  MpServicesInternal.h
+
+[Packages]
+  ArmPkg/ArmPkg.dec
+  ArmPlatformPkg/ArmPlatformPkg.dec
+  EmbeddedPkg/EmbeddedPkg.dec
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  ArmLib
+  ArmMmuLib
+  ArmSmcLib
+  BaseMemoryLib
+  CacheMaintenanceLib
+  DebugLib
+  HobLib
+  MemoryAllocationLib
+  UefiBootServicesTableLib
+  UefiDriverEntryPoint
+  UefiLib
+
+[Protocols]
+  gEfiMpServiceProtocolGuid            ## PRODUCES
+  gEfiLoadedImageProtocolGuid          ## CONSUMES
+
+[Guids]
+  gArmMpCoreInfoGuid
+
+[Depex]
+  TRUE
+
+[BuildOptions]
+  GCC:*_*_*_CC_FLAGS = -mstrict-align
diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
new file mode 100644
index 000000000000..ee13816ef64c
--- /dev/null
+++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
@@ -0,0 +1,351 @@
+/** @file
+
+Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
+Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
+Portions copyright (c) 2011, Apple Inc. All rights reserved.
+
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef MP_SERVICES_INTERNAL_H_
+#define MP_SERVICES_INTERNAL_H_
+
+#include <Protocol/Cpu.h>
+#include <Protocol/MpService.h>
+
+#include <Library/BaseLib.h>
+#include <Library/UefiLib.h>
+
+#define AP_STACK_SIZE  0x1000
+
+//
+// Internal Data Structures
+//
+
+//
+// AP state
+//
+// The state transitions for an AP when it process a procedure are:
+//  Idle ----> Ready ----> Busy ----> Idle
+//       [BSP]       [AP]       [AP]
+//
+typedef enum {
+  CpuStateIdle,
+  CpuStateReady,
+  CpuStateBlocked,
+  CpuStateBusy,
+  CpuStateFinished,
+  CpuStateDisabled
+} CPU_STATE;
+
+//
+// Define Individual Processor Data block.
+//
+typedef struct {
+  EFI_PROCESSOR_INFORMATION    Info;
+  EFI_AP_PROCEDURE             Procedure;
+  VOID                         *Parameter;
+  CPU_STATE                    State;
+  EFI_EVENT                    CheckThisAPEvent;
+  UINTN                        Timeout;
+  UINTN                        TimeTaken;
+  VOID                         *Ttbr0;
+  UINTN                        Tcr;
+  UINTN                        Mair;
+} CPU_AP_DATA;
+
+//
+// Define MP data block which consumes individual processor block.
+//
+typedef struct {
+  UINTN               NumberOfProcessors;
+  UINTN               NumberOfEnabledProcessors;
+  EFI_EVENT           CheckAllAPsEvent;
+  EFI_EVENT           WaitEvent;
+  UINTN               FinishCount;
+  UINTN               StartCount;
+  EFI_AP_PROCEDURE    Procedure;
+  VOID                *ProcedureArgument;
+  BOOLEAN             SingleThread;
+  UINTN               StartedNumber;
+  CPU_AP_DATA         *CpuData;
+  UINTN               Timeout;
+  UINTN               *FailedList;
+  UINTN               FailedListIndex;
+  BOOLEAN             TimeoutActive;
+} CPU_MP_DATA;
+
+/** Secondary core entry point.
+
+**/
+VOID
+ApEntryPoint (
+  VOID
+  );
+
+/** C entry-point for the AP.
+    This function gets called from the assembly function ApEntryPoint.
+**/
+VOID
+ApProcedure (
+  VOID
+  );
+
+/** Turns on the specified core using PSCI and executes the user-supplied
+    function that's been configured via a previous call to SetApProcedure.
+
+   @param ProcessorIndex The index of the core to turn on.
+
+   @retval EFI_SUCCESS       The processor was successfully turned on.
+   @retval EFI_DEVICE_ERROR  An error occurred turning the processor on.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+DispatchCpu (
+  IN UINTN  ProcessorIndex
+  );
+
+/** Returns whether the specified processor is the BSP.
+
+   @param[in] ProcessorIndex The index the processor to check.
+
+   @return TRUE if the processor is the BSP, FALSE otherwise.
+**/
+STATIC
+BOOLEAN
+IsProcessorBSP (
+  UINTN  ProcessorIndex
+  );
+
+/** Returns whether the processor executing this function is the BSP.
+
+   @return Whether the current processor is the BSP.
+**/
+STATIC
+BOOLEAN
+IsCurrentProcessorBSP (
+  VOID
+  );
+
+/** Returns whether the specified processor is enabled.
+
+   @param[in] ProcessorIndex The index of the processor to check.
+
+   @return TRUE if the processor is enabled, FALSE otherwise.
+**/
+STATIC
+BOOLEAN
+IsProcessorEnabled (
+  UINTN  ProcessorIndex
+  );
+
+/** Configures the processor context with the user-supplied procedure and
+    argument.
+
+   @param CpuData           The processor context.
+   @param Procedure         The user-supplied procedure.
+   @param ProcedureArgument The user-supplied procedure argument.
+
+**/
+STATIC
+VOID
+SetApProcedure (
+  IN   CPU_AP_DATA       *CpuData,
+  IN   EFI_AP_PROCEDURE  Procedure,
+  IN   VOID              *ProcedureArgument
+  );
+
+/**
+  Get the Application Processors state.
+
+  @param[in]  CpuData    The pointer to CPU_AP_DATA of specified AP
+
+  @return  The AP status
+**/
+CPU_STATE
+GetApState (
+  IN  CPU_AP_DATA  *CpuData
+  );
+
+/** Returns the index of the next processor that is blocked.
+
+   @param[out] NextNumber The index of the next blocked processor.
+
+   @retval EFI_SUCCESS   Successfully found the next blocked processor.
+   @retval EFI_NOT_FOUND There are no blocked processors.
+
+**/
+STATIC
+EFI_STATUS
+GetNextBlockedNumber (
+  OUT UINTN  *NextNumber
+  );
+
+/** Stalls the BSP for the minimum of gPollInterval and Timeout.
+
+   @param[in]  Timeout    The time limit in microseconds remaining for
+                          APs to return from Procedure.
+
+   @retval     StallTime  Time of execution stall.
+**/
+STATIC
+UINTN
+CalculateAndStallInterval (
+  IN UINTN  Timeout
+  );
+
+/** Returns whether all processors are in the idle state.
+
+   @return Whether all the processors are idle.
+
+**/
+STATIC
+BOOLEAN
+CheckAllCpusReady (
+  VOID
+  );
+
+/** Sets up the state for the StartupAllAPs function.
+
+   @param SingleThread Whether the APs will execute sequentially.
+
+**/
+STATIC
+VOID
+StartupAllAPsPrepareState (
+  IN BOOLEAN  SingleThread
+  );
+
+/** Handles execution of StartupAllAPs when a WaitEvent has been specified.
+
+   @param Procedure         The user-supplied procedure.
+   @param ProcedureArgument The user-supplied procedure argument.
+   @param WaitEvent         The wait event to be signaled when the work is
+                            complete or a timeout has occurred.
+   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
+                                indicates an infinite timeout.
+
+   @return EFI_SUCCESS on success.
+**/
+STATIC
+EFI_STATUS
+StartupAllAPsWithWaitEvent (
+  IN EFI_AP_PROCEDURE  Procedure,
+  IN VOID              *ProcedureArgument,
+  IN EFI_EVENT         WaitEvent,
+  IN UINTN             TimeoutInMicroseconds
+  );
+
+/** Handles execution of StartupAllAPs when no wait event has been specified.
+
+   @param Procedure             The user-supplied procedure.
+   @param ProcedureArgument     The user-supplied procedure argument.
+   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
+                                indicates an infinite timeout.
+   @param SingleThread          Whether the APs will execute sequentially.
+   @param FailedCpuList         User-supplied pointer for list of failed CPUs.
+
+   @return EFI_SUCCESS on success.
+**/
+STATIC
+EFI_STATUS
+StartupAllAPsNoWaitEvent (
+  IN EFI_AP_PROCEDURE  Procedure,
+  IN VOID              *ProcedureArgument,
+  IN UINTN             TimeoutInMicroseconds,
+  IN BOOLEAN           SingleThread,
+  IN UINTN             **FailedCpuList
+  );
+
+/** Adds the specified processor the list of failed processors.
+
+   @param ProcessorIndex The processor index to add.
+   @param ApState         Processor state.
+
+**/
+STATIC
+VOID
+AddProcessorToFailedList (
+  UINTN      ProcessorIndex,
+  CPU_STATE  ApState
+  );
+
+/** Handles the StartupAllAPs case where the timeout has occurred.
+
+**/
+STATIC
+VOID
+ProcessStartupAllAPsTimeout (
+  VOID
+  );
+
+/**
+  If a timeout is specified in StartupAllAps(), a timer is set, which invokes
+  this procedure periodically to check whether all APs have finished.
+
+  @param[in] Event   The WaitEvent the user supplied.
+  @param[in] Context The event context.
+**/
+STATIC
+VOID
+EFIAPI
+CheckAllAPsStatus (
+  IN  EFI_EVENT  Event,
+  IN  VOID       *Context
+  );
+
+/** Invoked periodically via a timer to check the state of the processor.
+
+   @param Event   The event supplied by the timer expiration.
+   @param Context The processor context.
+
+**/
+STATIC
+VOID
+EFIAPI
+CheckThisAPStatus (
+  IN  EFI_EVENT  Event,
+  IN  VOID       *Context
+  );
+
+/**
+  This function is called by all processors (both BSP and AP) once and collects
+  MP related data.
+
+  @param BSP            TRUE if the processor is the BSP.
+  @param Mpidr          The MPIDR for the specified processor. This should be
+                        the full MPIDR and not only the affinity bits.
+  @param ProcessorIndex The index of the processor.
+
+  @return EFI_SUCCESS if the data for the processor collected and filled in.
+
+**/
+STATIC
+EFI_STATUS
+FillInProcessorInformation (
+  IN BOOLEAN  BSP,
+  IN UINTN    Mpidr,
+  IN UINTN    ProcessorIndex
+  );
+
+/**
+  Event notification function called when the EFI_EVENT_GROUP_READY_TO_BOOT is
+  signaled. After this point, non-blocking mode is no longer allowed.
+
+  @param  Event     Event whose notification function is being invoked.
+  @param  Context   The pointer to the notification function's context,
+                    which is implementation-dependent.
+
+**/
+STATIC
+VOID
+EFIAPI
+ReadyToBootSignaled (
+  IN  EFI_EVENT  Event,
+  IN  VOID       *Context
+  );
+
+#endif /* MP_SERVICES_INTERNAL_H_ */
diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
new file mode 100644
index 000000000000..8cea203c7e34
--- /dev/null
+++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
@@ -0,0 +1,1774 @@
+/** @file
+  Construct MP Services Protocol.
+
+  The MP Services Protocol provides a generalized way of performing following tasks:
+    - Retrieving information of multi-processor environment and MP-related status of
+      specific processors.
+    - Dispatching user-provided function to APs.
+    - Maintain MP-related processor status.
+
+  The MP Services Protocol must be produced on any system with more than one logical
+  processor.
+
+  The Protocol is available only during boot time.
+
+  MP Services Protocol is hardware-independent. Most of the logic of this protocol
+  is architecturally neutral. It abstracts the multi-processor environment and
+  status of processors, and provides interfaces to retrieve information, maintain,
+  and dispatch.
+
+  MP Services Protocol may be consumed by ACPI module. The ACPI module may use this
+  protocol to retrieve data that are needed for an MP platform and report them to OS.
+  MP Services Protocol may also be used to program and configure processors, such
+  as MTRR synchronization for memory space attributes setting in DXE Services.
+  MP Services Protocol may be used by non-CPU DXE drivers to speed up platform boot
+  by taking advantage of the processing capabilities of the APs, for example, using
+  APs to help test system memory in parallel with other device initialization.
+  Diagnostics applications may also use this protocol for multi-processor.
+
+  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <PiDxe.h>
+
+#include <Library/ArmLib.h>
+#include <Library/ArmMmuLib.h>
+#include <Library/ArmPlatformLib.h>
+#include <Library/ArmSmcLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/CacheMaintenanceLib.h>
+#include <Library/DebugLib.h>
+#include <Library/HobLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+#include <IndustryStandard/ArmStdSmc.h>
+#include <Ppi/ArmMpCoreInfo.h>
+#include <Protocol/LoadedImage.h>
+
+#include "MpServicesInternal.h"
+
+#define POLL_INTERVAL_US  50000
+
+#define GET_MPIDR_AFFINITY_BITS(x)  ((x) & 0xFF00FFFFFF)
+
+#define MPIDR_MT_BIT  BIT24
+
+STATIC CPU_MP_DATA  mCpuMpData;
+STATIC BOOLEAN      mNonBlockingModeAllowed;
+UINT64              *gApStacksBase;
+UINT64              *gProcessorIDs;
+CONST UINT64        gApStackSize = AP_STACK_SIZE;
+
+STATIC
+BOOLEAN
+IsCurrentProcessorBSP (
+  VOID
+  );
+
+/** Turns on the specified core using PSCI and executes the user-supplied
+    function that's been configured via a previous call to SetApProcedure.
+
+    @param ProcessorIndex The index of the core to turn on.
+
+    @retval EFI_SUCCESS      Success.
+    @retval EFI_DEVICE_ERROR The processor could not be turned on.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+DispatchCpu (
+  IN UINTN  ProcessorIndex
+  )
+{
+  ARM_SMC_ARGS  Args;
+  EFI_STATUS    Status;
+
+  Status = EFI_SUCCESS;
+
+  mCpuMpData.CpuData[ProcessorIndex].State = CpuStateBusy;
+
+  /* Turn the AP on */
+  if (sizeof (Args.Arg0) == sizeof (UINT32)) {
+    Args.Arg0 = ARM_SMC_ID_PSCI_CPU_ON_AARCH32;
+  } else {
+    Args.Arg0 = ARM_SMC_ID_PSCI_CPU_ON_AARCH64;
+  }
+
+  Args.Arg1 = gProcessorIDs[ProcessorIndex];
+  Args.Arg2 = (UINTN)ApEntryPoint;
+
+  mCpuMpData.CpuData[ProcessorIndex].Tcr   = ArmGetTCR ();
+  mCpuMpData.CpuData[ProcessorIndex].Mair  = ArmGetMAIR ();
+  mCpuMpData.CpuData[ProcessorIndex].Ttbr0 = ArmGetTTBR0BaseAddress ();
+  WriteBackDataCacheRange (&mCpuMpData.CpuData[ProcessorIndex], sizeof (CPU_AP_DATA));
+
+  ArmCallSmc (&Args);
+
+  if (Args.Arg0 != ARM_SMC_PSCI_RET_SUCCESS) {
+    DEBUG ((DEBUG_ERROR, "PSCI_CPU_ON call failed: %d\n", Args.Arg0));
+    Status = EFI_DEVICE_ERROR;
+  }
+
+  return Status;
+}
+
+/** Returns whether the specified processor is the BSP.
+
+  @param[in] ProcessorIndex The index the processor to check.
+
+  @return TRUE if the processor is the BSP, FALSE otherwise.
+**/
+STATIC
+BOOLEAN
+IsProcessorBSP (
+  UINTN  ProcessorIndex
+  )
+{
+  EFI_PROCESSOR_INFORMATION  *CpuInfo;
+
+  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
+
+  return (CpuInfo->StatusFlag & PROCESSOR_AS_BSP_BIT) != 0;
+}
+
+/** Get the Application Processors state.
+
+  @param[in]  CpuData    The pointer to CPU_AP_DATA of specified AP.
+
+  @return The AP status.
+**/
+CPU_STATE
+GetApState (
+  IN  CPU_AP_DATA  *CpuData
+  )
+{
+  return CpuData->State;
+}
+
+/** Configures the processor context with the user-supplied procedure and
+    argument.
+
+   @param CpuData           The processor context.
+   @param Procedure         The user-supplied procedure.
+   @param ProcedureArgument The user-supplied procedure argument.
+
+**/
+STATIC
+VOID
+SetApProcedure (
+  IN   CPU_AP_DATA       *CpuData,
+  IN   EFI_AP_PROCEDURE  Procedure,
+  IN   VOID              *ProcedureArgument
+  )
+{
+  ASSERT (CpuData != NULL);
+  ASSERT (Procedure != NULL);
+
+  CpuData->Parameter = ProcedureArgument;
+  CpuData->Procedure = Procedure;
+}
+
+/** Returns the index of the next processor that is blocked.
+
+   @param[out] NextNumber The index of the next blocked processor.
+
+   @retval EFI_SUCCESS   Successfully found the next blocked processor.
+   @retval EFI_NOT_FOUND There are no blocked processors.
+
+**/
+STATIC
+EFI_STATUS
+GetNextBlockedNumber (
+  OUT UINTN  *NextNumber
+  )
+{
+  UINTN        Index;
+  CPU_STATE    State;
+  CPU_AP_DATA  *CpuData;
+
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    CpuData = &mCpuMpData.CpuData[Index];
+    if (IsProcessorBSP (Index)) {
+      // Skip BSP
+      continue;
+    }
+
+    State = CpuData->State;
+
+    if (State == CpuStateBlocked) {
+      *NextNumber = Index;
+      return EFI_SUCCESS;
+    }
+  }
+
+  return EFI_NOT_FOUND;
+}
+
+/** Stalls the BSP for the minimum of POLL_INTERVAL_US and Timeout.
+
+   @param[in]  Timeout    The time limit in microseconds remaining for
+                          APs to return from Procedure.
+
+   @retval     StallTime  Time of execution stall.
+**/
+STATIC
+UINTN
+CalculateAndStallInterval (
+  IN UINTN  Timeout
+  )
+{
+  UINTN  StallTime;
+
+  if ((Timeout < POLL_INTERVAL_US) && (Timeout != 0)) {
+    StallTime = Timeout;
+  } else {
+    StallTime = POLL_INTERVAL_US;
+  }
+
+  gBS->Stall (StallTime);
+
+  return StallTime;
+}
+
+/**
+  This service retrieves the number of logical processor in the platform
+  and the number of those logical processors that are enabled on this boot.
+  This service may only be called from the BSP.
+
+  This function is used to retrieve the following information:
+    - The number of logical processors that are present in the system.
+    - The number of enabled logical processors in the system at the instant
+      this call is made.
+
+  Because MP Service Protocol provides services to enable and disable processors
+  dynamically, the number of enabled logical processors may vary during the
+  course of a boot session.
+
+  If this service is called from an AP, then EFI_DEVICE_ERROR is returned.
+  If NumberOfProcessors or NumberOfEnabledProcessors is NULL, then
+  EFI_INVALID_PARAMETER is returned. Otherwise, the total number of processors
+  is returned in NumberOfProcessors, the number of currently enabled processor
+  is returned in NumberOfEnabledProcessors, and EFI_SUCCESS is returned.
+
+  @param[in]  This                        A pointer to the
+                                          EFI_MP_SERVICES_PROTOCOL instance.
+  @param[out] NumberOfProcessors          Pointer to the total number of logical
+                                          processors in the system, including
+                                          the BSP and disabled APs.
+  @param[out] NumberOfEnabledProcessors   Pointer to the number of enabled
+                                          logical processors that exist in the
+                                          system, including the BSP.
+
+  @retval EFI_SUCCESS             The number of logical processors and enabled
+                                  logical processors was retrieved.
+  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
+  @retval EFI_INVALID_PARAMETER   NumberOfProcessors is NULL.
+  @retval EFI_INVALID_PARAMETER   NumberOfEnabledProcessors is NULL.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+GetNumberOfProcessors (
+  IN  EFI_MP_SERVICES_PROTOCOL  *This,
+  OUT UINTN                     *NumberOfProcessors,
+  OUT UINTN                     *NumberOfEnabledProcessors
+  )
+{
+  if ((NumberOfProcessors == NULL) || (NumberOfEnabledProcessors == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (!IsCurrentProcessorBSP ()) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  *NumberOfProcessors        = mCpuMpData.NumberOfProcessors;
+  *NumberOfEnabledProcessors = mCpuMpData.NumberOfEnabledProcessors;
+  return EFI_SUCCESS;
+}
+
+/**
+  Gets detailed MP-related information on the requested processor at the
+  instant this call is made. This service may only be called from the BSP.
+
+  This service retrieves detailed MP-related information about any processor
+  on the platform. Note the following:
+    - The processor information may change during the course of a boot session.
+    - The information presented here is entirely MP related.
+
+  Information regarding the number of caches and their sizes, frequency of
+  operation, slot numbers is all considered platform-related information and is
+  not provided by this service.
+
+  @param[in]  This                  A pointer to the EFI_MP_SERVICES_PROTOCOL
+                                    instance.
+  @param[in]  ProcessorIndex        The index of the processor.
+  @param[out] ProcessorInfoBuffer   A pointer to the buffer where information
+                                    for the requested processor is deposited.
+
+  @retval EFI_SUCCESS             Processor information was returned.
+  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
+  @retval EFI_INVALID_PARAMETER   ProcessorInfoBuffer is NULL.
+  @retval EFI_NOT_FOUND           The processor with the handle specified by
+                                  ProcessorNumber does not exist in the platform.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+GetProcessorInfo (
+  IN  EFI_MP_SERVICES_PROTOCOL   *This,
+  IN  UINTN                      ProcessorIndex,
+  OUT EFI_PROCESSOR_INFORMATION  *ProcessorInfoBuffer
+  )
+{
+  if (ProcessorInfoBuffer == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (!IsCurrentProcessorBSP ()) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  ProcessorIndex &= ~CPU_V2_EXTENDED_TOPOLOGY;
+
+  if (ProcessorIndex >= mCpuMpData.NumberOfProcessors) {
+    return EFI_NOT_FOUND;
+  }
+
+  CopyMem (
+    ProcessorInfoBuffer,
+    &mCpuMpData.CpuData[ProcessorIndex],
+    sizeof (EFI_PROCESSOR_INFORMATION)
+    );
+  return EFI_SUCCESS;
+}
+
+/**
+  This service executes a caller provided function on all enabled APs. APs can
+  run either simultaneously or one at a time in sequence. This service supports
+  both blocking and non-blocking requests. The non-blocking requests use EFI
+  events so the BSP can detect when the APs have finished. This service may only
+  be called from the BSP.
+
+  This function is used to dispatch all the enabled APs to the function
+  specified by Procedure.  If any enabled AP is busy, then EFI_NOT_READY is
+  returned immediately and Procedure is not started on any AP.
+
+  If SingleThread is TRUE, all the enabled APs execute the function specified by
+  Procedure one by one, in ascending order of processor handle number.
+  Otherwise, all the enabled APs execute the function specified by Procedure
+  simultaneously.
+
+  If WaitEvent is NULL, execution is in blocking mode. The BSP waits until all
+  APs finish or TimeoutInMicroseconds expires. Otherwise, execution is in
+  non-blocking mode, and the BSP returns from this service without waiting for
+  APs. If a non-blocking mode is requested after the UEFI Event
+  EFI_EVENT_GROUP_READY_TO_BOOT is signaled, then EFI_UNSUPPORTED must be
+  returned.
+
+  If the timeout specified by TimeoutInMicroseconds expires before all APs
+  return from Procedure, then Procedure on the failed APs is terminated.
+  All enabled APs are always available for further calls to
+  EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and
+  EFI_MP_SERVICES_PROTOCOL.StartupThisAP(). If FailedCpuList is not NULL, its
+  content points to the list of processor handle numbers in which Procedure was
+  terminated.
+
+  Note: It is the responsibility of the consumer of the
+  EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() to make sure that the nature of the
+  code that is executed on the BSP and the dispatched APs is well controlled.
+  The MP Services Protocol does not guarantee that the Procedure function is
+  MP-safe. Hence, the tasks that can be run in parallel are limited to certain
+  independent tasks and well-controlled exclusive code. EFI services and
+  protocols may not be called by APs unless otherwise specified.
+
+  In blocking execution mode, BSP waits until all APs finish or
+  TimeoutInMicroseconds expires.
+
+  In non-blocking execution mode, BSP is freed to return to the caller and then
+  proceed to the next task without having to wait for APs. The following
+  sequence needs to occur in a non-blocking execution mode:
+
+    -# The caller that intends to use this MP Services Protocol in non-blocking
+       mode creates WaitEvent by calling the EFI CreateEvent() service.  The
+       caller invokes EFI_MP_SERVICES_PROTOCOL.StartupAllAPs(). If the parameter
+       WaitEvent is not NULL, then StartupAllAPs() executes in non-blocking
+       mode. It requests the function specified by Procedure to be started on
+       all the enabled APs, and releases the BSP to continue with other tasks.
+    -# The caller can use the CheckEvent() and WaitForEvent() services to check
+       the state of the WaitEvent created in step 1.
+    -# When the APs complete their task or TimeoutInMicroSecondss expires, the
+       MP Service signals WaitEvent by calling the EFI SignalEvent() function.
+       If FailedCpuList is not NULL, its content is available when WaitEvent is
+       signaled. If all APs returned from Procedure prior to the timeout, then
+       FailedCpuList is set to NULL. If not all APs return from Procedure before
+       the timeout, then FailedCpuList is filled in with the list of the failed
+       APs. The buffer is allocated by MP Service Protocol using AllocatePool().
+       It is the caller's responsibility to free the buffer with FreePool()
+       service.
+    -# This invocation of SignalEvent() function informs the caller that invoked
+       EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() that either all the APs
+       completed the specified task or a timeout occurred. The contents of
+       FailedCpuList can be examined to determine which APs did not complete the
+       specified task prior to the timeout.
+
+  @param[in]  This                    A pointer to the EFI_MP_SERVICES_PROTOCOL
+                                      instance.
+  @param[in]  Procedure               A pointer to the function to be run on
+                                      enabled APs of the system. See type
+                                      EFI_AP_PROCEDURE.
+  @param[in]  SingleThread            If TRUE, then all the enabled APs execute
+                                      the function specified by Procedure one by
+                                      one, in ascending order of processor
+                                      handle number.  If FALSE, then all the
+                                      enabled APs execute the function specified
+                                      by Procedure simultaneously.
+  @param[in]  WaitEvent               The event created by the caller with
+                                      CreateEvent() service.  If it is NULL,
+                                      then execute in blocking mode. BSP waits
+                                      until all APs finish or
+                                      TimeoutInMicroseconds expires.  If it's
+                                      not NULL, then execute in non-blocking
+                                      mode. BSP requests the function specified
+                                      by Procedure to be started on all the
+                                      enabled APs, and go on executing
+                                      immediately. If all return from Procedure,
+                                      or TimeoutInMicroseconds expires, this
+                                      event is signaled. The BSP can use the
+                                      CheckEvent() or WaitForEvent()
+                                      services to check the state of event. Type
+                                      EFI_EVENT is defined in CreateEvent() in
+                                      the Unified Extensible Firmware Interface
+                                      Specification.
+  @param[in]  TimeoutInMicroseconds   Indicates the time limit in microseconds
+                                      for APs to return from Procedure, either
+                                      for blocking or non-blocking mode. Zero
+                                      means infinity.  If the timeout expires
+                                      before all APs return from Procedure, then
+                                      Procedure on the failed APs is terminated.
+                                      All enabled APs are available for next
+                                      function assigned by
+                                      EFI_MP_SERVICES_PROTOCOL.StartupAllAPs()
+                                      or EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
+                                      If the timeout expires in blocking mode,
+                                      BSP returns EFI_TIMEOUT.  If the timeout
+                                      expires in non-blocking mode, WaitEvent
+                                      is signaled with SignalEvent().
+  @param[in]  ProcedureArgument       The parameter passed into Procedure for
+                                      all APs.
+  @param[out] FailedCpuList           If NULL, this parameter is ignored.
+                                      Otherwise, if all APs finish successfully,
+                                      then its content is set to NULL. If not
+                                      all APs finish before timeout expires,
+                                      then its content is set to address of the
+                                      buffer holding handle numbers of the
+                                      failed APs.
+                                      The buffer is allocated by MP Service
+                                      Protocol, and it's the caller's
+                                      responsibility to free the buffer with
+                                      FreePool() service.
+                                      In blocking mode, it is ready for
+                                      consumption when the call returns. In
+                                      non-blocking mode, it is ready when
+                                      WaitEvent is signaled. The list of failed
+                                      CPU is terminated by  END_OF_CPU_LIST.
+
+  @retval EFI_SUCCESS             In blocking mode, all APs have finished before
+                                  the timeout expired.
+  @retval EFI_SUCCESS             In non-blocking mode, function has been
+                                  dispatched to all enabled APs.
+  @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the
+                                  UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
+                                  signaled.
+  @retval EFI_DEVICE_ERROR        Caller processor is AP.
+  @retval EFI_NOT_STARTED         No enabled APs exist in the system.
+  @retval EFI_NOT_READY           Any enabled APs are busy.
+  @retval EFI_TIMEOUT             In blocking mode, the timeout expired before
+                                  all enabled APs have finished.
+  @retval EFI_INVALID_PARAMETER   Procedure is NULL.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+StartupAllAPs (
+  IN  EFI_MP_SERVICES_PROTOCOL  *This,
+  IN  EFI_AP_PROCEDURE          Procedure,
+  IN  BOOLEAN                   SingleThread,
+  IN  EFI_EVENT                 WaitEvent               OPTIONAL,
+  IN  UINTN                     TimeoutInMicroseconds,
+  IN  VOID                      *ProcedureArgument      OPTIONAL,
+  OUT UINTN                     **FailedCpuList         OPTIONAL
+  )
+{
+  EFI_STATUS  Status;
+
+  if (!IsCurrentProcessorBSP ()) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  if (mCpuMpData.NumberOfProcessors == 1) {
+    return EFI_NOT_STARTED;
+  }
+
+  if (Procedure == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if ((WaitEvent != NULL) && !mNonBlockingModeAllowed) {
+    return EFI_UNSUPPORTED;
+  }
+
+  if (!CheckAllCpusReady ()) {
+    return EFI_NOT_READY;
+  }
+
+  if (FailedCpuList != NULL) {
+    mCpuMpData.FailedList = AllocatePool (
+                              (mCpuMpData.NumberOfProcessors + 1) *
+                              sizeof (UINTN)
+                              );
+    if (mCpuMpData.FailedList == NULL) {
+      return EFI_OUT_OF_RESOURCES;
+    }
+
+    SetMemN (
+      mCpuMpData.FailedList,
+      (mCpuMpData.NumberOfProcessors + 1) *
+      sizeof (UINTN),
+      END_OF_CPU_LIST
+      );
+    mCpuMpData.FailedListIndex = 0;
+    *FailedCpuList             = mCpuMpData.FailedList;
+  }
+
+  StartupAllAPsPrepareState (SingleThread);
+
+  if (WaitEvent != NULL) {
+    Status = StartupAllAPsWithWaitEvent (
+               Procedure,
+               ProcedureArgument,
+               WaitEvent,
+               TimeoutInMicroseconds
+               );
+  } else {
+    Status = StartupAllAPsNoWaitEvent (
+               Procedure,
+               ProcedureArgument,
+               TimeoutInMicroseconds,
+               SingleThread,
+               FailedCpuList
+               );
+  }
+
+  return Status;
+}
+
+/**
+  This service lets the caller get one enabled AP to execute a caller-provided
+  function. The caller can request the BSP to either wait for the completion
+  of the AP or just proceed with the next task by using the EFI event mechanism.
+  See EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() for more details on non-blocking
+  execution support.  This service may only be called from the BSP.
+
+  This function is used to dispatch one enabled AP to the function specified by
+  Procedure passing in the argument specified by ProcedureArgument.  If WaitEvent
+  is NULL, execution is in blocking mode. The BSP waits until the AP finishes or
+  TimeoutInMicroSecondss expires. Otherwise, execution is in non-blocking mode.
+  BSP proceeds to the next task without waiting for the AP. If a non-blocking mode
+  is requested after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled,
+  then EFI_UNSUPPORTED must be returned.
+
+  If the timeout specified by TimeoutInMicroseconds expires before the AP returns
+  from Procedure, then execution of Procedure by the AP is terminated. The AP is
+  available for subsequent calls to EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and
+  EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
+
+  @param[in]  This                    A pointer to the EFI_MP_SERVICES_PROTOCOL
+                                      instance.
+  @param[in]  Procedure               A pointer to the function to be run on
+                                      enabled APs of the system. See type
+                                      EFI_AP_PROCEDURE.
+  @param[in]  ProcessorNumber         The handle number of the AP. The range is
+                                      from 0 to the total number of logical
+                                      processors minus 1. The total number of
+                                      logical processors can be retrieved by
+                                      EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
+  @param[in]  WaitEvent               The event created by the caller with CreateEvent()
+                                      service.  If it is NULL, then execute in
+                                      blocking mode. BSP waits until all APs finish
+                                      or TimeoutInMicroseconds expires.  If it's
+                                      not NULL, then execute in non-blocking mode.
+                                      BSP requests the function specified by
+                                      Procedure to be started on all the enabled
+                                      APs, and go on executing immediately. If
+                                      all return from Procedure or TimeoutInMicroseconds
+                                      expires, this event is signaled. The BSP
+                                      can use the CheckEvent() or WaitForEvent()
+                                      services to check the state of event.  Type
+                                      EFI_EVENT is defined in CreateEvent() in
+                                      the Unified Extensible Firmware Interface
+                                      Specification.
+  @param[in]  TimeoutInMicroseconds   Indicates the time limit in microseconds for
+                                      APs to return from Procedure, either for
+                                      blocking or non-blocking mode. Zero means
+                                      infinity.  If the timeout expires before
+                                      all APs return from Procedure, then Procedure
+                                      on the failed APs is terminated. All enabled
+                                      APs are available for next function assigned
+                                      by EFI_MP_SERVICES_PROTOCOL.StartupAllAPs()
+                                      or EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
+                                      If the timeout expires in blocking mode,
+                                      BSP returns EFI_TIMEOUT.  If the timeout
+                                      expires in non-blocking mode, WaitEvent
+                                      is signaled with SignalEvent().
+  @param[in]  ProcedureArgument       The parameter passed into Procedure for
+                                      all APs.
+  @param[out] Finished                If NULL, this parameter is ignored.  In
+                                      blocking mode, this parameter is ignored.
+                                      In non-blocking mode, if AP returns from
+                                      Procedure before the timeout expires, its
+                                      content is set to TRUE. Otherwise, the
+                                      value is set to FALSE. The caller can
+                                      determine if the AP returned from Procedure
+                                      by evaluating this value.
+
+  @retval EFI_SUCCESS             In blocking mode, specified AP finished before
+                                  the timeout expires.
+  @retval EFI_SUCCESS             In non-blocking mode, the function has been
+                                  dispatched to specified AP.
+  @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the
+                                  UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
+                                  signaled.
+  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
+  @retval EFI_TIMEOUT             In blocking mode, the timeout expired before
+                                  the specified AP has finished.
+  @retval EFI_NOT_READY           The specified AP is busy.
+  @retval EFI_NOT_FOUND           The processor with the handle specified by
+                                  ProcessorNumber does not exist.
+  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP or disabled AP.
+  @retval EFI_INVALID_PARAMETER   Procedure is NULL.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+StartupThisAP (
+  IN  EFI_MP_SERVICES_PROTOCOL  *This,
+  IN  EFI_AP_PROCEDURE          Procedure,
+  IN  UINTN                     ProcessorNumber,
+  IN  EFI_EVENT                 WaitEvent               OPTIONAL,
+  IN  UINTN                     TimeoutInMicroseconds,
+  IN  VOID                      *ProcedureArgument      OPTIONAL,
+  OUT BOOLEAN                   *Finished               OPTIONAL
+  )
+{
+  EFI_STATUS   Status;
+  UINTN        Timeout;
+  CPU_AP_DATA  *CpuData;
+
+  if (!IsCurrentProcessorBSP ()) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  if (Procedure == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (ProcessorNumber >= mCpuMpData.NumberOfProcessors) {
+    return EFI_NOT_FOUND;
+  }
+
+  CpuData = &mCpuMpData.CpuData[ProcessorNumber];
+
+  if (IsProcessorBSP (ProcessorNumber)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (!IsProcessorEnabled (ProcessorNumber)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (GetApState (CpuData) != CpuStateIdle) {
+    return EFI_NOT_READY;
+  }
+
+  if ((WaitEvent != NULL) && !mNonBlockingModeAllowed) {
+    return EFI_UNSUPPORTED;
+  }
+
+  Timeout = TimeoutInMicroseconds;
+
+  mCpuMpData.StartCount  = 1;
+  mCpuMpData.FinishCount = 0;
+
+  SetApProcedure (
+    CpuData,
+    Procedure,
+    ProcedureArgument
+    );
+
+  Status = DispatchCpu (ProcessorNumber);
+  if (EFI_ERROR (Status)) {
+    CpuData->State = CpuStateIdle;
+    return EFI_NOT_READY;
+  }
+
+  if (WaitEvent != NULL) {
+    // Non Blocking
+    mCpuMpData.WaitEvent = WaitEvent;
+    gBS->SetTimer (
+           CpuData->CheckThisAPEvent,
+           TimerPeriodic,
+           POLL_INTERVAL_US
+           );
+    return EFI_SUCCESS;
+  }
+
+  // Blocking
+  while (TRUE) {
+    if (GetApState (CpuData) == CpuStateFinished) {
+      CpuData->State = CpuStateIdle;
+      break;
+    }
+
+    if ((TimeoutInMicroseconds != 0) && (Timeout == 0)) {
+      return EFI_TIMEOUT;
+    }
+
+    Timeout -= CalculateAndStallInterval (Timeout);
+  }
+
+  return EFI_SUCCESS;
+}
+
+/**
+  This service switches the requested AP to be the BSP from that point onward.
+  This service changes the BSP for all purposes.   This call can only be
+  performed by the current BSP.
+
+  This service switches the requested AP to be the BSP from that point onward.
+  This service changes the BSP for all purposes. The new BSP can take over the
+  execution of the old BSP and continue seamlessly from where the old one left
+  off. This service may not be supported after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT
+  is signaled.
+
+  If the BSP cannot be switched prior to the return from this service, then
+  EFI_UNSUPPORTED must be returned.
+
+  @param[in] This              A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
+  @param[in] ProcessorNumber   The handle number of AP that is to become the new
+                               BSP. The range is from 0 to the total number of
+                               logical processors minus 1. The total number of
+                               logical processors can be retrieved by
+                               EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
+  @param[in] EnableOldBSP      If TRUE, then the old BSP will be listed as an
+                               enabled AP. Otherwise, it will be disabled.
+
+  @retval EFI_SUCCESS             BSP successfully switched.
+  @retval EFI_UNSUPPORTED         Switching the BSP cannot be completed prior to
+                                  this service returning.
+  @retval EFI_UNSUPPORTED         Switching the BSP is not supported.
+  @retval EFI_SUCCESS             The calling processor is an AP.
+  @retval EFI_NOT_FOUND           The processor with the handle specified by
+                                  ProcessorNumber does not exist.
+  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the current BSP or
+                                  a disabled AP.
+  @retval EFI_NOT_READY           The specified AP is busy.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+SwitchBSP (
+  IN EFI_MP_SERVICES_PROTOCOL  *This,
+  IN  UINTN                    ProcessorNumber,
+  IN  BOOLEAN                  EnableOldBSP
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  This service lets the caller enable or disable an AP from this point onward.
+  This service may only be called from the BSP.
+
+  This service allows the caller enable or disable an AP from this point onward.
+  The caller can optionally specify the health status of the AP by Health. If
+  an AP is being disabled, then the state of the disabled AP is implementation
+  dependent. If an AP is enabled, then the implementation must guarantee that a
+  complete initialization sequence is performed on the AP, so the AP is in a state
+  that is compatible with an MP operating system. This service may not be supported
+  after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled.
+
+  If the enable or disable AP operation cannot be completed prior to the return
+  from this service, then EFI_UNSUPPORTED must be returned.
+
+  @param[in] This              A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
+  @param[in] ProcessorNumber   The handle number of AP that is to become the new
+                               BSP. The range is from 0 to the total number of
+                               logical processors minus 1. The total number of
+                               logical processors can be retrieved by
+                               EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
+  @param[in] EnableAP          Specifies the new state for the processor for
+                               enabled, FALSE for disabled.
+  @param[in] HealthFlag        If not NULL, a pointer to a value that specifies
+                               the new health status of the AP. This flag
+                               corresponds to StatusFlag defined in
+                               EFI_MP_SERVICES_PROTOCOL.GetProcessorInfo(). Only
+                               the PROCESSOR_HEALTH_STATUS_BIT is used. All other
+                               bits are ignored.  If it is NULL, this parameter
+                               is ignored.
+
+  @retval EFI_SUCCESS             The specified AP was enabled or disabled successfully.
+  @retval EFI_UNSUPPORTED         Enabling or disabling an AP cannot be completed
+                                  prior to this service returning.
+  @retval EFI_UNSUPPORTED         Enabling or disabling an AP is not supported.
+  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
+  @retval EFI_NOT_FOUND           Processor with the handle specified by ProcessorNumber
+                                  does not exist.
+  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+EnableDisableAP (
+  IN  EFI_MP_SERVICES_PROTOCOL  *This,
+  IN  UINTN                     ProcessorNumber,
+  IN  BOOLEAN                   EnableAP,
+  IN  UINT32                    *HealthFlag OPTIONAL
+  )
+{
+  UINTN        StatusFlag;
+  CPU_AP_DATA  *CpuData;
+
+  StatusFlag = mCpuMpData.CpuData[ProcessorNumber].Info.StatusFlag;
+  CpuData    = &mCpuMpData.CpuData[ProcessorNumber];
+
+  if (!IsCurrentProcessorBSP ()) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  if (ProcessorNumber >= mCpuMpData.NumberOfProcessors) {
+    return EFI_NOT_FOUND;
+  }
+
+  if (IsProcessorBSP (ProcessorNumber)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (GetApState (CpuData) != CpuStateIdle) {
+    return EFI_UNSUPPORTED;
+  }
+
+  if (EnableAP) {
+    if (!IsProcessorEnabled (ProcessorNumber)) {
+      mCpuMpData.NumberOfEnabledProcessors++;
+    }
+
+    StatusFlag |= PROCESSOR_ENABLED_BIT;
+  } else {
+    if (IsProcessorEnabled (ProcessorNumber)) {
+      mCpuMpData.NumberOfEnabledProcessors--;
+    }
+
+    StatusFlag &= ~PROCESSOR_ENABLED_BIT;
+  }
+
+  if (HealthFlag != NULL) {
+    StatusFlag &= ~PROCESSOR_HEALTH_STATUS_BIT;
+    StatusFlag |= (*HealthFlag & PROCESSOR_HEALTH_STATUS_BIT);
+  }
+
+  mCpuMpData.CpuData[ProcessorNumber].Info.StatusFlag = StatusFlag;
+  return EFI_SUCCESS;
+}
+
+/**
+  This return the handle number for the calling processor.  This service may be
+  called from the BSP and APs.
+
+  This service returns the processor handle number for the calling processor.
+  The returned value is in the range from 0 to the total number of logical
+  processors minus 1. The total number of logical processors can be retrieved
+  with EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors(). This service may be
+  called from the BSP and APs. If ProcessorNumber is NULL, then EFI_INVALID_PARAMETER
+  is returned. Otherwise, the current processors handle number is returned in
+  ProcessorNumber, and EFI_SUCCESS is returned.
+
+  @param[in] This              A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
+  @param[out] ProcessorNumber  The handle number of AP that is to become the new
+                               BSP. The range is from 0 to the total number of
+                               logical processors minus 1. The total number of
+                               logical processors can be retrieved by
+                               EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
+
+  @retval EFI_SUCCESS             The current processor handle number was returned
+                                  in ProcessorNumber.
+  @retval EFI_INVALID_PARAMETER   ProcessorNumber is NULL.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+WhoAmI (
+  IN EFI_MP_SERVICES_PROTOCOL  *This,
+  OUT UINTN                    *ProcessorNumber
+  )
+{
+  UINTN   Index;
+  UINT64  ProcessorId;
+
+  if (ProcessorNumber == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  ProcessorId = GET_MPIDR_AFFINITY_BITS (ArmReadMpidr ());
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    if (ProcessorId == gProcessorIDs[Index]) {
+      *ProcessorNumber = Index;
+      break;
+    }
+  }
+
+  return EFI_SUCCESS;
+}
+
+STATIC EFI_MP_SERVICES_PROTOCOL  mMpServicesProtocol = {
+  GetNumberOfProcessors,
+  GetProcessorInfo,
+  StartupAllAPs,
+  StartupThisAP,
+  SwitchBSP,
+  EnableDisableAP,
+  WhoAmI
+};
+
+/** Adds the specified processor the list of failed processors.
+
+   @param ProcessorIndex The processor index to add.
+   @param ApState        Processor state.
+
+**/
+STATIC
+VOID
+AddProcessorToFailedList (
+  UINTN      ProcessorIndex,
+  CPU_STATE  ApState
+  )
+{
+  UINTN    Index;
+  BOOLEAN  Found;
+
+  Found = FALSE;
+
+  if (ApState == CpuStateIdle) {
+    return;
+  }
+
+  // If we are retrying make sure we don't double count
+  for (Index = 0; Index < mCpuMpData.FailedListIndex; Index++) {
+    if (mCpuMpData.FailedList[Index] == ProcessorIndex) {
+      Found = TRUE;
+      break;
+    }
+  }
+
+  /* If the CPU isn't already in the FailedList, add it */
+  if (!Found) {
+    mCpuMpData.FailedList[mCpuMpData.FailedListIndex++] = Index;
+  }
+}
+
+/** Handles the StartupAllAPs case where the timeout has occurred.
+
+**/
+STATIC
+VOID
+ProcessStartupAllAPsTimeout (
+  VOID
+  )
+{
+  CPU_AP_DATA  *CpuData;
+  UINTN        Index;
+
+  if (mCpuMpData.FailedList == NULL) {
+    return;
+  }
+
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    CpuData = &mCpuMpData.CpuData[Index];
+    if (IsProcessorBSP (Index)) {
+      // Skip BSP
+      continue;
+    }
+
+    if (!IsProcessorEnabled (Index)) {
+      // Skip Disabled processors
+      continue;
+    }
+
+    CpuData = &mCpuMpData.CpuData[Index];
+    AddProcessorToFailedList (Index, GetApState (CpuData));
+  }
+}
+
+/** Updates the status of the APs.
+
+   @param[in] ProcessorIndex The index of the AP to update.
+**/
+STATIC
+VOID
+UpdateApStatus (
+  IN UINTN  ProcessorIndex
+  )
+{
+  EFI_STATUS   Status;
+  CPU_AP_DATA  *CpuData;
+  CPU_AP_DATA  *NextCpuData;
+  CPU_STATE    State;
+  UINTN        NextNumber;
+
+  CpuData = &mCpuMpData.CpuData[ProcessorIndex];
+
+  if (IsProcessorBSP (ProcessorIndex)) {
+    // Skip BSP
+    return;
+  }
+
+  if (!IsProcessorEnabled (ProcessorIndex)) {
+    // Skip Disabled processors
+    return;
+  }
+
+  State = GetApState (CpuData);
+
+  switch (State) {
+    case CpuStateFinished:
+      if (mCpuMpData.SingleThread) {
+        Status = GetNextBlockedNumber (&NextNumber);
+        if (!EFI_ERROR (Status)) {
+          NextCpuData = &mCpuMpData.CpuData[NextNumber];
+
+          NextCpuData->State = CpuStateReady;
+
+          SetApProcedure (
+            NextCpuData,
+            mCpuMpData.Procedure,
+            mCpuMpData.ProcedureArgument
+            );
+        }
+      }
+
+      CpuData->State = CpuStateIdle;
+      mCpuMpData.FinishCount++;
+      break;
+
+    default:
+      break;
+  }
+}
+
+/**
+  If a timeout is specified in StartupAllAps(), a timer is set, which invokes
+  this procedure periodically to check whether all APs have finished.
+
+  @param[in] Event   The WaitEvent the user supplied.
+  @param[in] Context The event context.
+**/
+STATIC
+VOID
+EFIAPI
+CheckAllAPsStatus (
+  IN  EFI_EVENT  Event,
+  IN  VOID       *Context
+  )
+{
+  UINTN  Index;
+
+  if (mCpuMpData.TimeoutActive) {
+    mCpuMpData.Timeout -= CalculateAndStallInterval (mCpuMpData.Timeout);
+  }
+
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    UpdateApStatus (Index);
+  }
+
+  if (mCpuMpData.TimeoutActive && (mCpuMpData.Timeout == 0)) {
+    ProcessStartupAllAPsTimeout ();
+
+    // Force terminal exit
+    mCpuMpData.FinishCount = mCpuMpData.StartCount;
+  }
+
+  if (mCpuMpData.FinishCount != mCpuMpData.StartCount) {
+    return;
+  }
+
+  gBS->SetTimer (
+         mCpuMpData.CheckAllAPsEvent,
+         TimerCancel,
+         0
+         );
+
+  if (mCpuMpData.FailedListIndex == 0) {
+    if (mCpuMpData.FailedList != NULL) {
+      FreePool (mCpuMpData.FailedList);
+      mCpuMpData.FailedList = NULL;
+    }
+  }
+
+  gBS->SignalEvent (mCpuMpData.WaitEvent);
+}
+
+/** Invoked periodically via a timer to check the state of the processor.
+
+   @param Event   The event supplied by the timer expiration.
+   @param Context The processor context.
+
+**/
+STATIC
+VOID
+EFIAPI
+CheckThisAPStatus (
+  IN  EFI_EVENT  Event,
+  IN  VOID       *Context
+  )
+{
+  EFI_STATUS   Status;
+  CPU_AP_DATA  *CpuData;
+  CPU_STATE    State;
+
+  CpuData             = Context;
+  CpuData->TimeTaken += POLL_INTERVAL_US;
+
+  State = GetApState (CpuData);
+
+  if (State == CpuStateFinished) {
+    Status = gBS->SetTimer (CpuData->CheckThisAPEvent, TimerCancel, 0);
+    ASSERT_EFI_ERROR (Status);
+
+    if (mCpuMpData.WaitEvent != NULL) {
+      Status = gBS->SignalEvent (mCpuMpData.WaitEvent);
+      ASSERT_EFI_ERROR (Status);
+    }
+
+    CpuData->State = CpuStateIdle;
+  }
+
+  if (CpuData->TimeTaken > CpuData->Timeout) {
+    if (mCpuMpData.WaitEvent != NULL) {
+      Status = gBS->SignalEvent (mCpuMpData.WaitEvent);
+      ASSERT_EFI_ERROR (Status);
+    }
+  }
+}
+
+/**
+  This function is called by all processors (both BSP and AP) once and collects
+  MP related data.
+
+  @param BSP            TRUE if the processor is the BSP.
+  @param Mpidr          The MPIDR for the specified processor. This should be
+                        the full MPIDR and not only the affinity bits.
+  @param ProcessorIndex The index of the processor.
+
+  @return EFI_SUCCESS if the data for the processor collected and filled in.
+
+**/
+STATIC
+EFI_STATUS
+FillInProcessorInformation (
+  IN BOOLEAN  BSP,
+  IN UINTN    Mpidr,
+  IN UINTN    ProcessorIndex
+  )
+{
+  EFI_PROCESSOR_INFORMATION  *CpuInfo;
+
+  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
+
+  CpuInfo->ProcessorId = GET_MPIDR_AFFINITY_BITS (Mpidr);
+  CpuInfo->StatusFlag  = PROCESSOR_ENABLED_BIT | PROCESSOR_HEALTH_STATUS_BIT;
+
+  if (BSP) {
+    CpuInfo->StatusFlag |= PROCESSOR_AS_BSP_BIT;
+  }
+
+  if ((Mpidr & MPIDR_MT_BIT) > 0) {
+    CpuInfo->Location.Package = GET_MPIDR_AFF2 (Mpidr);
+    CpuInfo->Location.Core    = GET_MPIDR_AFF1 (Mpidr);
+    CpuInfo->Location.Thread  = GET_MPIDR_AFF0 (Mpidr);
+
+    CpuInfo->ExtendedInformation.Location2.Package = GET_MPIDR_AFF3 (Mpidr);
+    CpuInfo->ExtendedInformation.Location2.Die     = GET_MPIDR_AFF2 (Mpidr);
+    CpuInfo->ExtendedInformation.Location2.Core    = GET_MPIDR_AFF1 (Mpidr);
+    CpuInfo->ExtendedInformation.Location2.Thread  = GET_MPIDR_AFF0 (Mpidr);
+  } else {
+    CpuInfo->Location.Package = GET_MPIDR_AFF1 (Mpidr);
+    CpuInfo->Location.Core    = GET_MPIDR_AFF0 (Mpidr);
+    CpuInfo->Location.Thread  = 0;
+
+    CpuInfo->ExtendedInformation.Location2.Package = GET_MPIDR_AFF2 (Mpidr);
+    CpuInfo->ExtendedInformation.Location2.Die     = GET_MPIDR_AFF1 (Mpidr);
+    CpuInfo->ExtendedInformation.Location2.Core    = GET_MPIDR_AFF0 (Mpidr);
+    CpuInfo->ExtendedInformation.Location2.Thread  = 0;
+  }
+
+  mCpuMpData.CpuData[ProcessorIndex].State = BSP ? CpuStateBusy : CpuStateIdle;
+
+  mCpuMpData.CpuData[ProcessorIndex].Procedure = NULL;
+  mCpuMpData.CpuData[ProcessorIndex].Parameter = NULL;
+
+  return EFI_SUCCESS;
+}
+
+/** Initializes the MP Services system data
+
+   @param NumberOfProcessors The number of processors, both BSP and AP.
+   @param CoreInfo           CPU information gathered earlier during boot.
+
+**/
+STATIC
+EFI_STATUS
+MpServicesInitialize (
+  IN   UINTN                NumberOfProcessors,
+  IN   CONST ARM_CORE_INFO  *CoreInfo
+  )
+{
+  EFI_STATUS  Status;
+  UINTN       Index;
+  EFI_EVENT   ReadyToBootEvent;
+  BOOLEAN     IsBsp;
+
+  //
+  // Clear the data structure area first.
+  //
+  ZeroMem (&mCpuMpData, sizeof (CPU_MP_DATA));
+  //
+  // First BSP fills and inits all known values, including its own records.
+  //
+  mCpuMpData.NumberOfProcessors        = NumberOfProcessors;
+  mCpuMpData.NumberOfEnabledProcessors = NumberOfProcessors;
+
+  mCpuMpData.CpuData = AllocateZeroPool (
+                         mCpuMpData.NumberOfProcessors * sizeof (CPU_AP_DATA)
+                         );
+
+  if (mCpuMpData.CpuData == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  /* Allocate one extra for the sentinel entry at the end */
+  gProcessorIDs = AllocatePool ((mCpuMpData.NumberOfProcessors + 1) * sizeof (UINT64));
+  ASSERT (gProcessorIDs != NULL);
+
+  Status = gBS->CreateEvent (
+                  EVT_TIMER | EVT_NOTIFY_SIGNAL,
+                  TPL_CALLBACK,
+                  CheckAllAPsStatus,
+                  NULL,
+                  &mCpuMpData.CheckAllAPsEvent
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  gApStacksBase = AllocatePages (
+                    EFI_SIZE_TO_PAGES (
+                      mCpuMpData.NumberOfProcessors *
+                      gApStackSize
+                      )
+                    );
+  ASSERT (gApStacksBase != NULL);
+
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    if (GET_MPIDR_AFFINITY_BITS (ArmReadMpidr ()) == CoreInfo[Index].Mpidr) {
+      IsBsp = TRUE;
+    } else {
+      IsBsp = FALSE;
+    }
+
+    FillInProcessorInformation (IsBsp, CoreInfo[Index].Mpidr, Index);
+
+    gProcessorIDs[Index] = mCpuMpData.CpuData[Index].Info.ProcessorId;
+
+    Status = gBS->CreateEvent (
+                    EVT_TIMER | EVT_NOTIFY_SIGNAL,
+                    TPL_CALLBACK,
+                    CheckThisAPStatus,
+                    (VOID *)&mCpuMpData.CpuData[Index],
+                    &mCpuMpData.CpuData[Index].CheckThisAPEvent
+                    );
+    ASSERT_EFI_ERROR (Status);
+  }
+
+  gProcessorIDs[Index] = MAX_UINT64;
+
+  //
+  // The global pointer variables as well as the gProcessorIDs array contents
+  // are accessed by the other cores so we must clean them to the PoC
+  //
+  WriteBackDataCacheRange (&gProcessorIDs, sizeof (UINT64 *));
+  WriteBackDataCacheRange (&gApStacksBase, sizeof (UINT64 *));
+
+  WriteBackDataCacheRange (
+    gProcessorIDs,
+    (mCpuMpData.NumberOfProcessors + 1) * sizeof (UINT64)
+    );
+
+  Status = EfiCreateEventReadyToBootEx (
+             TPL_CALLBACK,
+             ReadyToBootSignaled,
+             NULL,
+             &ReadyToBootEvent
+             );
+  ASSERT_EFI_ERROR (Status);
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Event notification function called when the EFI_EVENT_GROUP_READY_TO_BOOT is
+  signaled. After this point, non-blocking mode is no longer allowed.
+
+  @param  Event     Event whose notification function is being invoked.
+  @param  Context   The pointer to the notification function's context,
+                    which is implementation-dependent.
+
+**/
+STATIC
+VOID
+EFIAPI
+ReadyToBootSignaled (
+  IN  EFI_EVENT  Event,
+  IN  VOID       *Context
+  )
+{
+  mNonBlockingModeAllowed = FALSE;
+}
+
+/** Initialize multi-processor support.
+
+  @param ImageHandle  Image handle.
+  @param SystemTable  System table.
+
+  @return EFI_SUCCESS on success, or an error code.
+
+**/
+EFI_STATUS
+EFIAPI
+ArmPsciMpServicesDxeInitialize (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS                 Status;
+  EFI_HANDLE                 Handle;
+  UINTN                      MaxCpus;
+  EFI_LOADED_IMAGE_PROTOCOL  *Image;
+  EFI_HOB_GENERIC_HEADER     *Hob;
+  VOID                       *HobData;
+  UINTN                      HobDataSize;
+  CONST ARM_CORE_INFO        *CoreInfo;
+
+  MaxCpus = 1;
+
+  DEBUG ((DEBUG_INFO, "Starting MP services\n"));
+
+  Status = gBS->HandleProtocol (
+                  ImageHandle,
+                  &gEfiLoadedImageProtocolGuid,
+                  (VOID **)&Image
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Parts of the code in this driver may be executed by other cores running
+  // with the MMU off so we need to ensure that everything is clean to the
+  // point of coherency (PoC)
+  //
+  WriteBackDataCacheRange (Image->ImageBase, Image->ImageSize);
+
+  Status = gBS->HandleProtocol (
+                  ImageHandle,
+                  &gEfiLoadedImageProtocolGuid,
+                  (VOID **)&Image
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Parts of the code in this driver may be executed by other cores running
+  // with the MMU off so we need to ensure that everything is clean to the
+  // point of coherency (PoC)
+  //
+  WriteBackDataCacheRange (Image->ImageBase, Image->ImageSize);
+
+  Hob = GetFirstGuidHob (&gArmMpCoreInfoGuid);
+  if (Hob != NULL) {
+    HobData     = GET_GUID_HOB_DATA (Hob);
+    HobDataSize = GET_GUID_HOB_DATA_SIZE (Hob);
+    CoreInfo    = (ARM_CORE_INFO *)HobData;
+    MaxCpus     = HobDataSize / sizeof (ARM_CORE_INFO);
+  }
+
+  if (MaxCpus == 1) {
+    DEBUG ((DEBUG_WARN, "Trying to use EFI_MP_SERVICES_PROTOCOL on a UP system"));
+    // We are not MP so nothing to do
+    return EFI_NOT_FOUND;
+  }
+
+  Status = MpServicesInitialize (MaxCpus, CoreInfo);
+  if (Status != EFI_SUCCESS) {
+    ASSERT_EFI_ERROR (Status);
+    return Status;
+  }
+
+  //
+  // Now install the MP services protocol.
+  //
+  Handle = NULL;
+  Status = gBS->InstallMultipleProtocolInterfaces (
+                  &Handle,
+                  &gEfiMpServiceProtocolGuid,
+                  &mMpServicesProtocol,
+                  NULL
+                  );
+  ASSERT_EFI_ERROR (Status);
+  return Status;
+}
+
+/** C entry-point for the AP.
+    This function gets called from the assembly function ApEntryPoint.
+
+**/
+VOID
+ApProcedure (
+  VOID
+  )
+{
+  ARM_SMC_ARGS      Args;
+  EFI_AP_PROCEDURE  UserApProcedure;
+  VOID              *UserApParameter;
+  UINTN             ProcessorIndex;
+
+  WhoAmI (&mMpServicesProtocol, &ProcessorIndex);
+
+  /* Fetch the user-supplied procedure and parameter to execute */
+  UserApProcedure = mCpuMpData.CpuData[ProcessorIndex].Procedure;
+  UserApParameter = mCpuMpData.CpuData[ProcessorIndex].Parameter;
+
+  // Configure the MMU and caches
+  ArmSetTCR (mCpuMpData.CpuData[ProcessorIndex].Tcr);
+  ArmSetTTBR0 (mCpuMpData.CpuData[ProcessorIndex].Ttbr0);
+  ArmSetMAIR (mCpuMpData.CpuData[ProcessorIndex].Mair);
+  ArmDisableAlignmentCheck ();
+  ArmEnableStackAlignmentCheck ();
+  ArmEnableInstructionCache ();
+  ArmEnableDataCache ();
+  ArmEnableMmu ();
+
+  UserApProcedure (UserApParameter);
+
+  mCpuMpData.CpuData[ProcessorIndex].State = CpuStateFinished;
+
+  ArmDataMemoryBarrier ();
+
+  /* Since we're finished with this AP, turn it off */
+  Args.Arg0 = ARM_SMC_ID_PSCI_CPU_OFF;
+  ArmCallSmc (&Args);
+
+  /* Should never be reached */
+  ASSERT (FALSE);
+  CpuDeadLoop ();
+}
+
+/** Returns whether the processor executing this function is the BSP.
+
+    @return Whether the current processor is the BSP.
+**/
+STATIC
+BOOLEAN
+IsCurrentProcessorBSP (
+  VOID
+  )
+{
+  EFI_STATUS  Status;
+  UINTN       ProcessorIndex;
+
+  Status = WhoAmI (&mMpServicesProtocol, &ProcessorIndex);
+  if (EFI_ERROR (Status)) {
+    ASSERT_EFI_ERROR (Status);
+    return FALSE;
+  }
+
+  return IsProcessorBSP (ProcessorIndex);
+}
+
+/** Returns whether the specified processor is enabled.
+
+   @param[in] ProcessorIndex The index of the processor to check.
+
+   @return TRUE if the processor is enabled, FALSE otherwise.
+**/
+STATIC
+BOOLEAN
+IsProcessorEnabled (
+  UINTN  ProcessorIndex
+  )
+{
+  EFI_PROCESSOR_INFORMATION  *CpuInfo;
+
+  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
+
+  return (CpuInfo->StatusFlag & PROCESSOR_ENABLED_BIT) != 0;
+}
+
+/** Returns whether all processors are in the idle state.
+
+   @return Whether all the processors are idle.
+
+**/
+STATIC
+BOOLEAN
+CheckAllCpusReady (
+  VOID
+  )
+{
+  UINTN        Index;
+  CPU_AP_DATA  *CpuData;
+
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    CpuData = &mCpuMpData.CpuData[Index];
+    if (IsProcessorBSP (Index)) {
+      // Skip BSP
+      continue;
+    }
+
+    if (!IsProcessorEnabled (Index)) {
+      // Skip Disabled processors
+      continue;
+    }
+
+    if (GetApState (CpuData) != CpuStateIdle) {
+      return FALSE;
+    }
+  }
+
+  return TRUE;
+}
+
+/** Sets up the state for the StartupAllAPs function.
+
+   @param SingleThread Whether the APs will execute sequentially.
+
+**/
+STATIC
+VOID
+StartupAllAPsPrepareState (
+  IN BOOLEAN  SingleThread
+  )
+{
+  UINTN        Index;
+  CPU_STATE    APInitialState;
+  CPU_AP_DATA  *CpuData;
+
+  mCpuMpData.FinishCount  = 0;
+  mCpuMpData.StartCount   = 0;
+  mCpuMpData.SingleThread = SingleThread;
+
+  APInitialState = CpuStateReady;
+
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    CpuData = &mCpuMpData.CpuData[Index];
+
+    //
+    // Get APs prepared, and put failing APs into FailedCpuList.
+    // If "SingleThread", only 1 AP will put into ready state, other AP will be
+    // put into ready state 1 by 1, until the previous 1 finished its task.
+    // If not "SingleThread", all APs are put into ready state from the
+    // beginning
+    //
+
+    if (IsProcessorBSP (Index)) {
+      // Skip BSP
+      continue;
+    }
+
+    if (!IsProcessorEnabled (Index)) {
+      // Skip Disabled processors
+      if (mCpuMpData.FailedList != NULL) {
+        mCpuMpData.FailedList[mCpuMpData.FailedListIndex++] = Index;
+      }
+
+      continue;
+    }
+
+    ASSERT (GetApState (CpuData) == CpuStateIdle);
+    CpuData->State = APInitialState;
+
+    mCpuMpData.StartCount++;
+    if (SingleThread) {
+      APInitialState = CpuStateBlocked;
+    }
+  }
+}
+
+/** Handles execution of StartupAllAPs when a WaitEvent has been specified.
+
+   @param Procedure         The user-supplied procedure.
+   @param ProcedureArgument The user-supplied procedure argument.
+   @param WaitEvent         The wait event to be signaled when the work is
+                            complete or a timeout has occurred.
+   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
+                                indicates an infinite timeout.
+
+   @return EFI_SUCCESS on success.
+**/
+STATIC
+EFI_STATUS
+StartupAllAPsWithWaitEvent (
+  IN EFI_AP_PROCEDURE  Procedure,
+  IN VOID              *ProcedureArgument,
+  IN EFI_EVENT         WaitEvent,
+  IN UINTN             TimeoutInMicroseconds
+  )
+{
+  EFI_STATUS   Status;
+  UINTN        Index;
+  CPU_AP_DATA  *CpuData;
+
+  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+    CpuData = &mCpuMpData.CpuData[Index];
+    if (IsProcessorBSP (Index)) {
+      // Skip BSP
+      continue;
+    }
+
+    if (!IsProcessorEnabled (Index)) {
+      // Skip Disabled processors
+      continue;
+    }
+
+    if (GetApState (CpuData) == CpuStateReady) {
+      SetApProcedure (CpuData, Procedure, ProcedureArgument);
+    }
+  }
+
+  //
+  // Save data into private data structure, and create timer to poll AP state
+  // before exiting
+  //
+  mCpuMpData.Procedure         = Procedure;
+  mCpuMpData.ProcedureArgument = ProcedureArgument;
+  mCpuMpData.WaitEvent         = WaitEvent;
+  mCpuMpData.Timeout           = TimeoutInMicroseconds;
+  mCpuMpData.TimeoutActive     = (BOOLEAN)(TimeoutInMicroseconds != 0);
+  Status                       = gBS->SetTimer (
+                                        mCpuMpData.CheckAllAPsEvent,
+                                        TimerPeriodic,
+                                        POLL_INTERVAL_US
+                                        );
+  return Status;
+}
+
+/** Handles execution of StartupAllAPs when no wait event has been specified.
+
+   @param Procedure             The user-supplied procedure.
+   @param ProcedureArgument     The user-supplied procedure argument.
+   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
+                                indicates an infinite timeout.
+   @param SingleThread          Whether the APs will execute sequentially.
+   @param FailedCpuList         User-supplied pointer for list of failed CPUs.
+
+   @return EFI_SUCCESS on success.
+**/
+STATIC
+EFI_STATUS
+StartupAllAPsNoWaitEvent (
+  IN EFI_AP_PROCEDURE  Procedure,
+  IN VOID              *ProcedureArgument,
+  IN UINTN             TimeoutInMicroseconds,
+  IN BOOLEAN           SingleThread,
+  IN UINTN             **FailedCpuList
+  )
+{
+  EFI_STATUS   Status;
+  UINTN        Index;
+  UINTN        NextIndex;
+  UINTN        Timeout;
+  CPU_AP_DATA  *CpuData;
+
+  Timeout = TimeoutInMicroseconds;
+
+  while (TRUE) {
+    for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
+      CpuData = &mCpuMpData.CpuData[Index];
+      if (IsProcessorBSP (Index)) {
+        // Skip BSP
+        continue;
+      }
+
+      if (!IsProcessorEnabled (Index)) {
+        // Skip Disabled processors
+        continue;
+      }
+
+      switch (GetApState (CpuData)) {
+        case CpuStateReady:
+          SetApProcedure (CpuData, Procedure, ProcedureArgument);
+          Status = DispatchCpu (Index);
+          if (EFI_ERROR (Status)) {
+            CpuData->State = CpuStateIdle;
+            Status         = EFI_NOT_READY;
+            goto Done;
+          }
+
+          break;
+
+        case CpuStateFinished:
+          mCpuMpData.FinishCount++;
+          if (SingleThread) {
+            Status = GetNextBlockedNumber (&NextIndex);
+            if (!EFI_ERROR (Status)) {
+              mCpuMpData.CpuData[NextIndex].State = CpuStateReady;
+            }
+          }
+
+          CpuData->State = CpuStateIdle;
+          break;
+
+        default:
+          break;
+      }
+    }
+
+    if (mCpuMpData.FinishCount == mCpuMpData.StartCount) {
+      Status = EFI_SUCCESS;
+      goto Done;
+    }
+
+    if ((TimeoutInMicroseconds != 0) && (Timeout == 0)) {
+      Status = EFI_TIMEOUT;
+      goto Done;
+    }
+
+    Timeout -= CalculateAndStallInterval (Timeout);
+  }
+
+Done:
+  if (FailedCpuList != NULL) {
+    if (mCpuMpData.FailedListIndex == 0) {
+      FreePool (*FailedCpuList);
+      *FailedCpuList = NULL;
+    }
+  }
+
+  return Status;
+}
diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S
new file mode 100644
index 000000000000..a90fa8a0075f
--- /dev/null
+++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S
@@ -0,0 +1,57 @@
+#===============================================================================
+#  Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#===============================================================================
+
+.text
+.align 3
+
+#include <AsmMacroIoLibV8.h>
+#include <IndustryStandard/ArmStdSmc.h>
+
+#include "MpServicesInternal.h"
+
+GCC_ASM_IMPORT (gApStacksBase)
+GCC_ASM_IMPORT (gProcessorIDs)
+GCC_ASM_IMPORT (ApProcedure)
+GCC_ASM_IMPORT (gApStackSize)
+
+GCC_ASM_EXPORT (ApEntryPoint)
+
+// Entry-point for the AP
+// VOID
+// ApEntryPoint (
+//   VOID
+//   );
+ASM_PFX(ApEntryPoint):
+  mrs x0, mpidr_el1
+  // Mask the non-affinity bits
+  bic x0, x0, 0x00ff000000
+  and x0, x0, 0xffffffffff
+  ldr x1, gProcessorIDs
+  mov x2, 0                   // x2 = processor index
+
+// Find index in gProcessorIDs for current processor
+1:
+  ldr x3, [x1, x2, lsl #3]    // x4 = gProcessorIDs + x2 * 8
+  cmp x3, #-1                 // check if we've reached the end of gProcessorIDs
+  beq ProcessorNotFound
+  add x2, x2, 1               // x2++
+  cmp x0, x3                  // if mpidr_el1 != gProcessorIDs[x] then loop
+  bne 1b
+
+// Calculate stack address
+  // x2 contains the index for the current processor plus 1
+  ldr x0, gApStacksBase
+  ldr x1, gApStackSize
+  mul x3, x2, x1              // x3 = (ProcessorIndex + 1) * gApStackSize
+  add sp, x0, x3              // sp = gApStacksBase + x3
+  mov x29, xzr
+  bl ApProcedure              // doesn't return
+
+ProcessorNotFound:
+// Turn off the processor
+  MOV32 (w0, ARM_SMC_ID_PSCI_CPU_OFF)
+  smc #0
+  b .
-- 
2.30.2

Re: [edk2-devel] [PATCH 1/2] ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls

[Kun Qin]

Hi Rebecca,

Thanks for sending this patch. I have a few questions inline "[KQ]". 
Could you please help me to
understand the patch better? Thanks in advance.

Regards,
Kun

On 8/29/2022 8:59 AM, Rebecca Cran wrote:
> Add support for EFI_MP_SERVICES_PROTOCOL during the DXE phase under
> AArch64.
>
> PSCI_CPU_ON is called to power on the core, the supplied procedure is
> executed and PSCI_CPU_OFF is called to power off the core.
>
> Fixes contributed by Ard Biesheuvel.
>
> Signed-off-by: Rebecca Cran <rebecca@quicinc.com>
> ---
>   ArmPkg/ArmPkg.dsc                                            |    1 +
>   ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf |   55 +
>   ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h     |  351 ++++
>   ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c   | 1774 ++++++++++++++++++++
>   ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S                |   57 +
>   5 files changed, 2238 insertions(+)
>
> diff --git a/ArmPkg/ArmPkg.dsc b/ArmPkg/ArmPkg.dsc
> index 59fd8f295d4f..4716789402fc 100644
> --- a/ArmPkg/ArmPkg.dsc
> +++ b/ArmPkg/ArmPkg.dsc
> @@ -125,6 +125,7 @@ [Components.common]
>     ArmPkg/Drivers/CpuPei/CpuPei.inf
>     ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
>     ArmPkg/Drivers/ArmGic/ArmGicLib.inf
> +  ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
>     ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.inf
>     ArmPkg/Drivers/TimerDxe/TimerDxe.inf
>   
> diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
> new file mode 100644
> index 000000000000..2b109c72e0a0
> --- /dev/null
> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
> @@ -0,0 +1,55 @@
> +## @file
> +#  ARM MP services protocol driver
> +#
> +#  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 1.27
> +  BASE_NAME                      = ArmPsciMpServicesDxe
> +  FILE_GUID                      = 007ab472-dc4a-4df8-a5c2-abb4a327278c
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +
> +  ENTRY_POINT                    = ArmPsciMpServicesDxeInitialize
> +
> +[Sources.Common]
> +  ArmPsciMpServicesDxe.c
> +  MpFuncs.S
> +  MpServicesInternal.h
> +
> +[Packages]
> +  ArmPkg/ArmPkg.dec
> +  ArmPlatformPkg/ArmPlatformPkg.dec
> +  EmbeddedPkg/EmbeddedPkg.dec
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +
> +[LibraryClasses]
> +  ArmLib
> +  ArmMmuLib
> +  ArmSmcLib
> +  BaseMemoryLib
> +  CacheMaintenanceLib
> +  DebugLib
> +  HobLib
> +  MemoryAllocationLib
> +  UefiBootServicesTableLib
> +  UefiDriverEntryPoint
> +  UefiLib
> +
> +[Protocols]
> +  gEfiMpServiceProtocolGuid            ## PRODUCES
> +  gEfiLoadedImageProtocolGuid          ## CONSUMES
> +
> +[Guids]
> +  gArmMpCoreInfoGuid
> +
> +[Depex]
> +  TRUE
> +
> +[BuildOptions]
> +  GCC:*_*_*_CC_FLAGS = -mstrict-align
> diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
> new file mode 100644
> index 000000000000..ee13816ef64c
> --- /dev/null
> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
> @@ -0,0 +1,351 @@
> +/** @file
> +
> +Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
> +Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
> +Portions copyright (c) 2011, Apple Inc. All rights reserved.
> +
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef MP_SERVICES_INTERNAL_H_
> +#define MP_SERVICES_INTERNAL_H_
> +
> +#include <Protocol/Cpu.h>
> +#include <Protocol/MpService.h>
> +
> +#include <Library/BaseLib.h>
> +#include <Library/UefiLib.h>
> +
> +#define AP_STACK_SIZE  0x1000
> +
> +//
> +// Internal Data Structures
> +//
> +
> +//
> +// AP state
> +//
> +// The state transitions for an AP when it process a procedure are:
> +//  Idle ----> Ready ----> Busy ----> Idle
> +//       [BSP]       [AP]       [AP]
> +//
> +typedef enum {
> +  CpuStateIdle,
> +  CpuStateReady,
> +  CpuStateBlocked,
> +  CpuStateBusy,
> +  CpuStateFinished,
> +  CpuStateDisabled
> +} CPU_STATE;
> +
> +//
> +// Define Individual Processor Data block.
> +//
> +typedef struct {
> +  EFI_PROCESSOR_INFORMATION    Info;
> +  EFI_AP_PROCEDURE             Procedure;
> +  VOID                         *Parameter;
> +  CPU_STATE                    State;
> +  EFI_EVENT                    CheckThisAPEvent;
> +  UINTN                        Timeout;
> +  UINTN                        TimeTaken;
> +  VOID                         *Ttbr0;
> +  UINTN                        Tcr;
> +  UINTN                        Mair;
> +} CPU_AP_DATA;
> +
> +//
> +// Define MP data block which consumes individual processor block.
> +//
> +typedef struct {
> +  UINTN               NumberOfProcessors;
> +  UINTN               NumberOfEnabledProcessors;
> +  EFI_EVENT           CheckAllAPsEvent;
> +  EFI_EVENT           WaitEvent;
> +  UINTN               FinishCount;
> +  UINTN               StartCount;
> +  EFI_AP_PROCEDURE    Procedure;
> +  VOID                *ProcedureArgument;
> +  BOOLEAN             SingleThread;
> +  UINTN               StartedNumber;
> +  CPU_AP_DATA         *CpuData;
> +  UINTN               Timeout;
> +  UINTN               *FailedList;
> +  UINTN               FailedListIndex;
> +  BOOLEAN             TimeoutActive;
> +} CPU_MP_DATA;
> +
> +/** Secondary core entry point.
> +
> +**/
> +VOID
> +ApEntryPoint (
> +  VOID
> +  );
> +
> +/** C entry-point for the AP.
> +    This function gets called from the assembly function ApEntryPoint.
> +**/
> +VOID
> +ApProcedure (
> +  VOID
> +  );
> +
> +/** Turns on the specified core using PSCI and executes the user-supplied
> +    function that's been configured via a previous call to SetApProcedure.
> +
> +   @param ProcessorIndex The index of the core to turn on.
> +
> +   @retval EFI_SUCCESS       The processor was successfully turned on.
> +   @retval EFI_DEVICE_ERROR  An error occurred turning the processor on.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +DispatchCpu (
> +  IN UINTN  ProcessorIndex
> +  );
> +
> +/** Returns whether the specified processor is the BSP.
> +
> +   @param[in] ProcessorIndex The index the processor to check.
> +
> +   @return TRUE if the processor is the BSP, FALSE otherwise.
> +**/
> +STATIC
> +BOOLEAN
> +IsProcessorBSP (
> +  UINTN  ProcessorIndex
> +  );
> +
> +/** Returns whether the processor executing this function is the BSP.
> +
> +   @return Whether the current processor is the BSP.
> +**/
> +STATIC
> +BOOLEAN
> +IsCurrentProcessorBSP (
> +  VOID
> +  );
> +
> +/** Returns whether the specified processor is enabled.
> +
> +   @param[in] ProcessorIndex The index of the processor to check.
> +
> +   @return TRUE if the processor is enabled, FALSE otherwise.
> +**/
> +STATIC
> +BOOLEAN
> +IsProcessorEnabled (
> +  UINTN  ProcessorIndex
> +  );
> +
> +/** Configures the processor context with the user-supplied procedure and
> +    argument.
> +
> +   @param CpuData           The processor context.
> +   @param Procedure         The user-supplied procedure.
> +   @param ProcedureArgument The user-supplied procedure argument.
> +
> +**/
> +STATIC
> +VOID
> +SetApProcedure (
> +  IN   CPU_AP_DATA       *CpuData,
> +  IN   EFI_AP_PROCEDURE  Procedure,
> +  IN   VOID              *ProcedureArgument
> +  );
> +
> +/**
> +  Get the Application Processors state.
> +
> +  @param[in]  CpuData    The pointer to CPU_AP_DATA of specified AP
> +
> +  @return  The AP status
> +**/
> +CPU_STATE
> +GetApState (
> +  IN  CPU_AP_DATA  *CpuData
> +  );
> +
> +/** Returns the index of the next processor that is blocked.
> +
> +   @param[out] NextNumber The index of the next blocked processor.
> +
> +   @retval EFI_SUCCESS   Successfully found the next blocked processor.
> +   @retval EFI_NOT_FOUND There are no blocked processors.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +GetNextBlockedNumber (
> +  OUT UINTN  *NextNumber
> +  );
> +
> +/** Stalls the BSP for the minimum of gPollInterval and Timeout.
> +
> +   @param[in]  Timeout    The time limit in microseconds remaining for
> +                          APs to return from Procedure.
> +
> +   @retval     StallTime  Time of execution stall.
> +**/
> +STATIC
> +UINTN
> +CalculateAndStallInterval (
> +  IN UINTN  Timeout
> +  );
> +
> +/** Returns whether all processors are in the idle state.
> +
> +   @return Whether all the processors are idle.
> +
> +**/
> +STATIC
> +BOOLEAN
> +CheckAllCpusReady (
> +  VOID
> +  );
> +
> +/** Sets up the state for the StartupAllAPs function.
> +
> +   @param SingleThread Whether the APs will execute sequentially.
> +
> +**/
> +STATIC
> +VOID
> +StartupAllAPsPrepareState (
> +  IN BOOLEAN  SingleThread
> +  );
> +
> +/** Handles execution of StartupAllAPs when a WaitEvent has been specified.
> +
> +   @param Procedure         The user-supplied procedure.
> +   @param ProcedureArgument The user-supplied procedure argument.
> +   @param WaitEvent         The wait event to be signaled when the work is
> +                            complete or a timeout has occurred.
> +   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
> +                                indicates an infinite timeout.
> +
> +   @return EFI_SUCCESS on success.
> +**/
> +STATIC
> +EFI_STATUS
> +StartupAllAPsWithWaitEvent (
> +  IN EFI_AP_PROCEDURE  Procedure,
> +  IN VOID              *ProcedureArgument,
> +  IN EFI_EVENT         WaitEvent,
> +  IN UINTN             TimeoutInMicroseconds
> +  );
> +
> +/** Handles execution of StartupAllAPs when no wait event has been specified.
> +
> +   @param Procedure             The user-supplied procedure.
> +   @param ProcedureArgument     The user-supplied procedure argument.
> +   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
> +                                indicates an infinite timeout.
> +   @param SingleThread          Whether the APs will execute sequentially.
> +   @param FailedCpuList         User-supplied pointer for list of failed CPUs.
> +
> +   @return EFI_SUCCESS on success.
> +**/
> +STATIC
> +EFI_STATUS
> +StartupAllAPsNoWaitEvent (
> +  IN EFI_AP_PROCEDURE  Procedure,
> +  IN VOID              *ProcedureArgument,
> +  IN UINTN             TimeoutInMicroseconds,
> +  IN BOOLEAN           SingleThread,
> +  IN UINTN             **FailedCpuList
> +  );
> +
> +/** Adds the specified processor the list of failed processors.
> +
> +   @param ProcessorIndex The processor index to add.
> +   @param ApState         Processor state.
> +
> +**/
> +STATIC
> +VOID
> +AddProcessorToFailedList (
> +  UINTN      ProcessorIndex,
> +  CPU_STATE  ApState
> +  );
> +
> +/** Handles the StartupAllAPs case where the timeout has occurred.
> +
> +**/
> +STATIC
> +VOID
> +ProcessStartupAllAPsTimeout (
> +  VOID
> +  );
> +
> +/**
> +  If a timeout is specified in StartupAllAps(), a timer is set, which invokes
> +  this procedure periodically to check whether all APs have finished.
> +
> +  @param[in] Event   The WaitEvent the user supplied.
> +  @param[in] Context The event context.
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +CheckAllAPsStatus (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  );
> +
> +/** Invoked periodically via a timer to check the state of the processor.
> +
> +   @param Event   The event supplied by the timer expiration.
> +   @param Context The processor context.
> +
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +CheckThisAPStatus (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  );
> +
> +/**
> +  This function is called by all processors (both BSP and AP) once and collects
> +  MP related data.
> +
> +  @param BSP            TRUE if the processor is the BSP.
> +  @param Mpidr          The MPIDR for the specified processor. This should be
> +                        the full MPIDR and not only the affinity bits.
> +  @param ProcessorIndex The index of the processor.
> +
> +  @return EFI_SUCCESS if the data for the processor collected and filled in.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +FillInProcessorInformation (
> +  IN BOOLEAN  BSP,
> +  IN UINTN    Mpidr,
> +  IN UINTN    ProcessorIndex
> +  );
> +
> +/**
> +  Event notification function called when the EFI_EVENT_GROUP_READY_TO_BOOT is
> +  signaled. After this point, non-blocking mode is no longer allowed.
> +
> +  @param  Event     Event whose notification function is being invoked.
> +  @param  Context   The pointer to the notification function's context,
> +                    which is implementation-dependent.
> +
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +ReadyToBootSignaled (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  );
> +
> +#endif /* MP_SERVICES_INTERNAL_H_ */
> diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
> new file mode 100644
> index 000000000000..8cea203c7e34
> --- /dev/null
> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
> @@ -0,0 +1,1774 @@
> +/** @file
> +  Construct MP Services Protocol.
> +
> +  The MP Services Protocol provides a generalized way of performing following tasks:
> +    - Retrieving information of multi-processor environment and MP-related status of
> +      specific processors.
> +    - Dispatching user-provided function to APs.
> +    - Maintain MP-related processor status.
> +
> +  The MP Services Protocol must be produced on any system with more than one logical
> +  processor.
> +
> +  The Protocol is available only during boot time.
> +
> +  MP Services Protocol is hardware-independent. Most of the logic of this protocol
> +  is architecturally neutral. It abstracts the multi-processor environment and
> +  status of processors, and provides interfaces to retrieve information, maintain,
> +  and dispatch.
> +
> +  MP Services Protocol may be consumed by ACPI module. The ACPI module may use this
> +  protocol to retrieve data that are needed for an MP platform and report them to OS.
> +  MP Services Protocol may also be used to program and configure processors, such
> +  as MTRR synchronization for memory space attributes setting in DXE Services.
> +  MP Services Protocol may be used by non-CPU DXE drivers to speed up platform boot
> +  by taking advantage of the processing capabilities of the APs, for example, using
> +  APs to help test system memory in parallel with other device initialization.
> +  Diagnostics applications may also use this protocol for multi-processor.
> +
> +  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <PiDxe.h>
> +
> +#include <Library/ArmLib.h>
> +#include <Library/ArmMmuLib.h>
> +#include <Library/ArmPlatformLib.h>
> +#include <Library/ArmSmcLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/CacheMaintenanceLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/HobLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiLib.h>
> +
> +#include <IndustryStandard/ArmStdSmc.h>
> +#include <Ppi/ArmMpCoreInfo.h>
> +#include <Protocol/LoadedImage.h>
> +
> +#include "MpServicesInternal.h"
> +
> +#define POLL_INTERVAL_US  50000
> +
> +#define GET_MPIDR_AFFINITY_BITS(x)  ((x) & 0xFF00FFFFFF)
> +
> +#define MPIDR_MT_BIT  BIT24
[KQ]: Is there any reason why this is not defined in a more formal 
place? I think that will allow the platform to use as well.
> +
> +STATIC CPU_MP_DATA  mCpuMpData;
> +STATIC BOOLEAN      mNonBlockingModeAllowed;
> +UINT64              *gApStacksBase;
> +UINT64              *gProcessorIDs;
> +CONST UINT64        gApStackSize = AP_STACK_SIZE;
> +
> +STATIC
> +BOOLEAN
> +IsCurrentProcessorBSP (
> +  VOID
> +  );
> +
> +/** Turns on the specified core using PSCI and executes the user-supplied
> +    function that's been configured via a previous call to SetApProcedure.
> +
> +    @param ProcessorIndex The index of the core to turn on.
> +
> +    @retval EFI_SUCCESS      Success.
> +    @retval EFI_DEVICE_ERROR The processor could not be turned on.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +DispatchCpu (
> +  IN UINTN  ProcessorIndex
> +  )
> +{
> +  ARM_SMC_ARGS  Args;
> +  EFI_STATUS    Status;
> +
> +  Status = EFI_SUCCESS;
> +
> +  mCpuMpData.CpuData[ProcessorIndex].State = CpuStateBusy;
> +
> +  /* Turn the AP on */
> +  if (sizeof (Args.Arg0) == sizeof (UINT32)) {
> +    Args.Arg0 = ARM_SMC_ID_PSCI_CPU_ON_AARCH32;
> +  } else {
> +    Args.Arg0 = ARM_SMC_ID_PSCI_CPU_ON_AARCH64;
> +  }
> +
> +  Args.Arg1 = gProcessorIDs[ProcessorIndex];
> +  Args.Arg2 = (UINTN)ApEntryPoint;
> +
> +  mCpuMpData.CpuData[ProcessorIndex].Tcr   = ArmGetTCR ();
> +  mCpuMpData.CpuData[ProcessorIndex].Mair  = ArmGetMAIR ();
> +  mCpuMpData.CpuData[ProcessorIndex].Ttbr0 = ArmGetTTBR0BaseAddress ();
> +  WriteBackDataCacheRange (&mCpuMpData.CpuData[ProcessorIndex], sizeof (CPU_AP_DATA));
> +
> +  ArmCallSmc (&Args);
> +
> +  if (Args.Arg0 != ARM_SMC_PSCI_RET_SUCCESS) {
> +    DEBUG ((DEBUG_ERROR, "PSCI_CPU_ON call failed: %d\n", Args.Arg0));
> +    Status = EFI_DEVICE_ERROR;
> +  }
> +
> +  return Status;
> +}
> +
> +/** Returns whether the specified processor is the BSP.
> +
> +  @param[in] ProcessorIndex The index the processor to check.
> +
> +  @return TRUE if the processor is the BSP, FALSE otherwise.
> +**/
> +STATIC
> +BOOLEAN
> +IsProcessorBSP (
> +  UINTN  ProcessorIndex
> +  )
> +{
> +  EFI_PROCESSOR_INFORMATION  *CpuInfo;
> +
> +  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
> +
> +  return (CpuInfo->StatusFlag & PROCESSOR_AS_BSP_BIT) != 0;
> +}
> +
> +/** Get the Application Processors state.
> +
> +  @param[in]  CpuData    The pointer to CPU_AP_DATA of specified AP.
> +
> +  @return The AP status.
> +**/
> +CPU_STATE
> +GetApState (
> +  IN  CPU_AP_DATA  *CpuData
> +  )
> +{
> +  return CpuData->State;
> +}
> +
> +/** Configures the processor context with the user-supplied procedure and
> +    argument.
> +
> +   @param CpuData           The processor context.
> +   @param Procedure         The user-supplied procedure.
> +   @param ProcedureArgument The user-supplied procedure argument.
> +
> +**/
> +STATIC
> +VOID
> +SetApProcedure (
> +  IN   CPU_AP_DATA       *CpuData,
> +  IN   EFI_AP_PROCEDURE  Procedure,
> +  IN   VOID              *ProcedureArgument
> +  )
> +{
> +  ASSERT (CpuData != NULL);
> +  ASSERT (Procedure != NULL);
> +
> +  CpuData->Parameter = ProcedureArgument;
> +  CpuData->Procedure = Procedure;
> +}
> +
> +/** Returns the index of the next processor that is blocked.
> +
> +   @param[out] NextNumber The index of the next blocked processor.
> +
> +   @retval EFI_SUCCESS   Successfully found the next blocked processor.
> +   @retval EFI_NOT_FOUND There are no blocked processors.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +GetNextBlockedNumber (
> +  OUT UINTN  *NextNumber
> +  )
> +{
> +  UINTN        Index;
> +  CPU_STATE    State;
> +  CPU_AP_DATA  *CpuData;
> +
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    CpuData = &mCpuMpData.CpuData[Index];
> +    if (IsProcessorBSP (Index)) {
> +      // Skip BSP
> +      continue;
> +    }
> +
> +    State = CpuData->State;
> +
> +    if (State == CpuStateBlocked) {
> +      *NextNumber = Index;
> +      return EFI_SUCCESS;
> +    }
> +  }
> +
> +  return EFI_NOT_FOUND;
> +}
> +
> +/** Stalls the BSP for the minimum of POLL_INTERVAL_US and Timeout.
> +
> +   @param[in]  Timeout    The time limit in microseconds remaining for
> +                          APs to return from Procedure.
> +
> +   @retval     StallTime  Time of execution stall.
> +**/
> +STATIC
> +UINTN
> +CalculateAndStallInterval (
> +  IN UINTN  Timeout
> +  )
> +{
> +  UINTN  StallTime;
> +
> +  if ((Timeout < POLL_INTERVAL_US) && (Timeout != 0)) {
> +    StallTime = Timeout;
> +  } else {
> +    StallTime = POLL_INTERVAL_US;
> +  }
> +
> +  gBS->Stall (StallTime);
> +
> +  return StallTime;
> +}
> +
> +/**
> +  This service retrieves the number of logical processor in the platform
> +  and the number of those logical processors that are enabled on this boot.
> +  This service may only be called from the BSP.
> +
> +  This function is used to retrieve the following information:
> +    - The number of logical processors that are present in the system.
> +    - The number of enabled logical processors in the system at the instant
> +      this call is made.
> +
> +  Because MP Service Protocol provides services to enable and disable processors
> +  dynamically, the number of enabled logical processors may vary during the
> +  course of a boot session.
> +
> +  If this service is called from an AP, then EFI_DEVICE_ERROR is returned.
> +  If NumberOfProcessors or NumberOfEnabledProcessors is NULL, then
> +  EFI_INVALID_PARAMETER is returned. Otherwise, the total number of processors
> +  is returned in NumberOfProcessors, the number of currently enabled processor
> +  is returned in NumberOfEnabledProcessors, and EFI_SUCCESS is returned.
> +
> +  @param[in]  This                        A pointer to the
> +                                          EFI_MP_SERVICES_PROTOCOL instance.
> +  @param[out] NumberOfProcessors          Pointer to the total number of logical
> +                                          processors in the system, including
> +                                          the BSP and disabled APs.
> +  @param[out] NumberOfEnabledProcessors   Pointer to the number of enabled
> +                                          logical processors that exist in the
> +                                          system, including the BSP.
> +
> +  @retval EFI_SUCCESS             The number of logical processors and enabled
> +                                  logical processors was retrieved.
> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
> +  @retval EFI_INVALID_PARAMETER   NumberOfProcessors is NULL.
> +  @retval EFI_INVALID_PARAMETER   NumberOfEnabledProcessors is NULL.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +GetNumberOfProcessors (
> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
> +  OUT UINTN                     *NumberOfProcessors,
> +  OUT UINTN                     *NumberOfEnabledProcessors
> +  )
> +{
> +  if ((NumberOfProcessors == NULL) || (NumberOfEnabledProcessors == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (!IsCurrentProcessorBSP ()) {
> +    return EFI_DEVICE_ERROR;
> +  }
> +
> +  *NumberOfProcessors        = mCpuMpData.NumberOfProcessors;
> +  *NumberOfEnabledProcessors = mCpuMpData.NumberOfEnabledProcessors;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Gets detailed MP-related information on the requested processor at the
> +  instant this call is made. This service may only be called from the BSP.
> +
> +  This service retrieves detailed MP-related information about any processor
> +  on the platform. Note the following:
> +    - The processor information may change during the course of a boot session.
> +    - The information presented here is entirely MP related.
> +
> +  Information regarding the number of caches and their sizes, frequency of
> +  operation, slot numbers is all considered platform-related information and is
> +  not provided by this service.
> +
> +  @param[in]  This                  A pointer to the EFI_MP_SERVICES_PROTOCOL
> +                                    instance.
> +  @param[in]  ProcessorIndex        The index of the processor.
> +  @param[out] ProcessorInfoBuffer   A pointer to the buffer where information
> +                                    for the requested processor is deposited.
> +
> +  @retval EFI_SUCCESS             Processor information was returned.
> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
> +  @retval EFI_INVALID_PARAMETER   ProcessorInfoBuffer is NULL.
> +  @retval EFI_NOT_FOUND           The processor with the handle specified by
> +                                  ProcessorNumber does not exist in the platform.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +GetProcessorInfo (
> +  IN  EFI_MP_SERVICES_PROTOCOL   *This,
> +  IN  UINTN                      ProcessorIndex,
> +  OUT EFI_PROCESSOR_INFORMATION  *ProcessorInfoBuffer
> +  )
> +{
> +  if (ProcessorInfoBuffer == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (!IsCurrentProcessorBSP ()) {
> +    return EFI_DEVICE_ERROR;
> +  }
> +
> +  ProcessorIndex &= ~CPU_V2_EXTENDED_TOPOLOGY;
> +
> +  if (ProcessorIndex >= mCpuMpData.NumberOfProcessors) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  CopyMem (
> +    ProcessorInfoBuffer,
> +    &mCpuMpData.CpuData[ProcessorIndex],
> +    sizeof (EFI_PROCESSOR_INFORMATION)
> +    );
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  This service executes a caller provided function on all enabled APs. APs can
> +  run either simultaneously or one at a time in sequence. This service supports
> +  both blocking and non-blocking requests. The non-blocking requests use EFI
> +  events so the BSP can detect when the APs have finished. This service may only
> +  be called from the BSP.
> +
> +  This function is used to dispatch all the enabled APs to the function
> +  specified by Procedure.  If any enabled AP is busy, then EFI_NOT_READY is
> +  returned immediately and Procedure is not started on any AP.
> +
> +  If SingleThread is TRUE, all the enabled APs execute the function specified by
> +  Procedure one by one, in ascending order of processor handle number.
> +  Otherwise, all the enabled APs execute the function specified by Procedure
> +  simultaneously.
> +
> +  If WaitEvent is NULL, execution is in blocking mode. The BSP waits until all
> +  APs finish or TimeoutInMicroseconds expires. Otherwise, execution is in
> +  non-blocking mode, and the BSP returns from this service without waiting for
> +  APs. If a non-blocking mode is requested after the UEFI Event
> +  EFI_EVENT_GROUP_READY_TO_BOOT is signaled, then EFI_UNSUPPORTED must be
> +  returned.
> +
> +  If the timeout specified by TimeoutInMicroseconds expires before all APs
> +  return from Procedure, then Procedure on the failed APs is terminated.
> +  All enabled APs are always available for further calls to
> +  EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and
> +  EFI_MP_SERVICES_PROTOCOL.StartupThisAP(). If FailedCpuList is not NULL, its
> +  content points to the list of processor handle numbers in which Procedure was
> +  terminated.
> +
> +  Note: It is the responsibility of the consumer of the
> +  EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() to make sure that the nature of the
> +  code that is executed on the BSP and the dispatched APs is well controlled.
> +  The MP Services Protocol does not guarantee that the Procedure function is
> +  MP-safe. Hence, the tasks that can be run in parallel are limited to certain
> +  independent tasks and well-controlled exclusive code. EFI services and
> +  protocols may not be called by APs unless otherwise specified.
> +
> +  In blocking execution mode, BSP waits until all APs finish or
> +  TimeoutInMicroseconds expires.
> +
> +  In non-blocking execution mode, BSP is freed to return to the caller and then
> +  proceed to the next task without having to wait for APs. The following
> +  sequence needs to occur in a non-blocking execution mode:
> +
> +    -# The caller that intends to use this MP Services Protocol in non-blocking
> +       mode creates WaitEvent by calling the EFI CreateEvent() service.  The
> +       caller invokes EFI_MP_SERVICES_PROTOCOL.StartupAllAPs(). If the parameter
> +       WaitEvent is not NULL, then StartupAllAPs() executes in non-blocking
> +       mode. It requests the function specified by Procedure to be started on
> +       all the enabled APs, and releases the BSP to continue with other tasks.
> +    -# The caller can use the CheckEvent() and WaitForEvent() services to check
> +       the state of the WaitEvent created in step 1.
> +    -# When the APs complete their task or TimeoutInMicroSecondss expires, the
> +       MP Service signals WaitEvent by calling the EFI SignalEvent() function.
> +       If FailedCpuList is not NULL, its content is available when WaitEvent is
> +       signaled. If all APs returned from Procedure prior to the timeout, then
> +       FailedCpuList is set to NULL. If not all APs return from Procedure before
> +       the timeout, then FailedCpuList is filled in with the list of the failed
> +       APs. The buffer is allocated by MP Service Protocol using AllocatePool().
> +       It is the caller's responsibility to free the buffer with FreePool()
> +       service.
> +    -# This invocation of SignalEvent() function informs the caller that invoked
> +       EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() that either all the APs
> +       completed the specified task or a timeout occurred. The contents of
> +       FailedCpuList can be examined to determine which APs did not complete the
> +       specified task prior to the timeout.
> +
> +  @param[in]  This                    A pointer to the EFI_MP_SERVICES_PROTOCOL
> +                                      instance.
> +  @param[in]  Procedure               A pointer to the function to be run on
> +                                      enabled APs of the system. See type
> +                                      EFI_AP_PROCEDURE.
> +  @param[in]  SingleThread            If TRUE, then all the enabled APs execute
> +                                      the function specified by Procedure one by
> +                                      one, in ascending order of processor
> +                                      handle number.  If FALSE, then all the
> +                                      enabled APs execute the function specified
> +                                      by Procedure simultaneously.
> +  @param[in]  WaitEvent               The event created by the caller with
> +                                      CreateEvent() service.  If it is NULL,
> +                                      then execute in blocking mode. BSP waits
> +                                      until all APs finish or
> +                                      TimeoutInMicroseconds expires.  If it's
> +                                      not NULL, then execute in non-blocking
> +                                      mode. BSP requests the function specified
> +                                      by Procedure to be started on all the
> +                                      enabled APs, and go on executing
> +                                      immediately. If all return from Procedure,
> +                                      or TimeoutInMicroseconds expires, this
> +                                      event is signaled. The BSP can use the
> +                                      CheckEvent() or WaitForEvent()
> +                                      services to check the state of event. Type
> +                                      EFI_EVENT is defined in CreateEvent() in
> +                                      the Unified Extensible Firmware Interface
> +                                      Specification.
> +  @param[in]  TimeoutInMicroseconds   Indicates the time limit in microseconds
> +                                      for APs to return from Procedure, either
> +                                      for blocking or non-blocking mode. Zero
> +                                      means infinity.  If the timeout expires
> +                                      before all APs return from Procedure, then
> +                                      Procedure on the failed APs is terminated.
> +                                      All enabled APs are available for next
> +                                      function assigned by
> +                                      EFI_MP_SERVICES_PROTOCOL.StartupAllAPs()
> +                                      or EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
> +                                      If the timeout expires in blocking mode,
> +                                      BSP returns EFI_TIMEOUT.  If the timeout
> +                                      expires in non-blocking mode, WaitEvent
> +                                      is signaled with SignalEvent().
> +  @param[in]  ProcedureArgument       The parameter passed into Procedure for
> +                                      all APs.
> +  @param[out] FailedCpuList           If NULL, this parameter is ignored.
> +                                      Otherwise, if all APs finish successfully,
> +                                      then its content is set to NULL. If not
> +                                      all APs finish before timeout expires,
> +                                      then its content is set to address of the
> +                                      buffer holding handle numbers of the
> +                                      failed APs.
> +                                      The buffer is allocated by MP Service
> +                                      Protocol, and it's the caller's
> +                                      responsibility to free the buffer with
> +                                      FreePool() service.
> +                                      In blocking mode, it is ready for
> +                                      consumption when the call returns. In
> +                                      non-blocking mode, it is ready when
> +                                      WaitEvent is signaled. The list of failed
> +                                      CPU is terminated by  END_OF_CPU_LIST.
> +
> +  @retval EFI_SUCCESS             In blocking mode, all APs have finished before
> +                                  the timeout expired.
> +  @retval EFI_SUCCESS             In non-blocking mode, function has been
> +                                  dispatched to all enabled APs.
> +  @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the
> +                                  UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
> +                                  signaled.
> +  @retval EFI_DEVICE_ERROR        Caller processor is AP.
> +  @retval EFI_NOT_STARTED         No enabled APs exist in the system.
> +  @retval EFI_NOT_READY           Any enabled APs are busy.
> +  @retval EFI_TIMEOUT             In blocking mode, the timeout expired before
> +                                  all enabled APs have finished.
> +  @retval EFI_INVALID_PARAMETER   Procedure is NULL.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +StartupAllAPs (
> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
> +  IN  EFI_AP_PROCEDURE          Procedure,
> +  IN  BOOLEAN                   SingleThread,
> +  IN  EFI_EVENT                 WaitEvent               OPTIONAL,
> +  IN  UINTN                     TimeoutInMicroseconds,
> +  IN  VOID                      *ProcedureArgument      OPTIONAL,
> +  OUT UINTN                     **FailedCpuList         OPTIONAL
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  if (!IsCurrentProcessorBSP ()) {
> +    return EFI_DEVICE_ERROR;
> +  }
> +
> +  if (mCpuMpData.NumberOfProcessors == 1) {
> +    return EFI_NOT_STARTED;
> +  }
> +
> +  if (Procedure == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if ((WaitEvent != NULL) && !mNonBlockingModeAllowed) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  if (!CheckAllCpusReady ()) {
> +    return EFI_NOT_READY;
> +  }
> +
> +  if (FailedCpuList != NULL) {
> +    mCpuMpData.FailedList = AllocatePool (
> +                              (mCpuMpData.NumberOfProcessors + 1) *
> +                              sizeof (UINTN)
> +                              );
> +    if (mCpuMpData.FailedList == NULL) {
> +      return EFI_OUT_OF_RESOURCES;
> +    }
> +
> +    SetMemN (
> +      mCpuMpData.FailedList,
> +      (mCpuMpData.NumberOfProcessors + 1) *
> +      sizeof (UINTN),
> +      END_OF_CPU_LIST
> +      );
> +    mCpuMpData.FailedListIndex = 0;
> +    *FailedCpuList             = mCpuMpData.FailedList;
> +  }
> +
> +  StartupAllAPsPrepareState (SingleThread);
> +
> +  if (WaitEvent != NULL) {
> +    Status = StartupAllAPsWithWaitEvent (
> +               Procedure,
> +               ProcedureArgument,
> +               WaitEvent,
> +               TimeoutInMicroseconds
> +               );
> +  } else {
> +    Status = StartupAllAPsNoWaitEvent (
> +               Procedure,
> +               ProcedureArgument,
> +               TimeoutInMicroseconds,
> +               SingleThread,
> +               FailedCpuList
> +               );
> +  }
> +
> +  return Status;
> +}
> +
> +/**
> +  This service lets the caller get one enabled AP to execute a caller-provided
> +  function. The caller can request the BSP to either wait for the completion
> +  of the AP or just proceed with the next task by using the EFI event mechanism.
> +  See EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() for more details on non-blocking
> +  execution support.  This service may only be called from the BSP.
> +
> +  This function is used to dispatch one enabled AP to the function specified by
> +  Procedure passing in the argument specified by ProcedureArgument.  If WaitEvent
> +  is NULL, execution is in blocking mode. The BSP waits until the AP finishes or
> +  TimeoutInMicroSecondss expires. Otherwise, execution is in non-blocking mode.
> +  BSP proceeds to the next task without waiting for the AP. If a non-blocking mode
> +  is requested after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled,
> +  then EFI_UNSUPPORTED must be returned.
> +
> +  If the timeout specified by TimeoutInMicroseconds expires before the AP returns
> +  from Procedure, then execution of Procedure by the AP is terminated. The AP is
> +  available for subsequent calls to EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and
> +  EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
> +
> +  @param[in]  This                    A pointer to the EFI_MP_SERVICES_PROTOCOL
> +                                      instance.
> +  @param[in]  Procedure               A pointer to the function to be run on
> +                                      enabled APs of the system. See type
> +                                      EFI_AP_PROCEDURE.
> +  @param[in]  ProcessorNumber         The handle number of the AP. The range is
> +                                      from 0 to the total number of logical
> +                                      processors minus 1. The total number of
> +                                      logical processors can be retrieved by
> +                                      EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
> +  @param[in]  WaitEvent               The event created by the caller with CreateEvent()
> +                                      service.  If it is NULL, then execute in
> +                                      blocking mode. BSP waits until all APs finish
> +                                      or TimeoutInMicroseconds expires.  If it's
> +                                      not NULL, then execute in non-blocking mode.
> +                                      BSP requests the function specified by
> +                                      Procedure to be started on all the enabled
> +                                      APs, and go on executing immediately. If
> +                                      all return from Procedure or TimeoutInMicroseconds
> +                                      expires, this event is signaled. The BSP
> +                                      can use the CheckEvent() or WaitForEvent()
> +                                      services to check the state of event.  Type
> +                                      EFI_EVENT is defined in CreateEvent() in
> +                                      the Unified Extensible Firmware Interface
> +                                      Specification.
> +  @param[in]  TimeoutInMicroseconds   Indicates the time limit in microseconds for
> +                                      APs to return from Procedure, either for
> +                                      blocking or non-blocking mode. Zero means
> +                                      infinity.  If the timeout expires before
> +                                      all APs return from Procedure, then Procedure
> +                                      on the failed APs is terminated. All enabled
> +                                      APs are available for next function assigned
> +                                      by EFI_MP_SERVICES_PROTOCOL.StartupAllAPs()
> +                                      or EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
> +                                      If the timeout expires in blocking mode,
> +                                      BSP returns EFI_TIMEOUT.  If the timeout
> +                                      expires in non-blocking mode, WaitEvent
> +                                      is signaled with SignalEvent().
> +  @param[in]  ProcedureArgument       The parameter passed into Procedure for
> +                                      all APs.
> +  @param[out] Finished                If NULL, this parameter is ignored.  In
> +                                      blocking mode, this parameter is ignored.
> +                                      In non-blocking mode, if AP returns from
> +                                      Procedure before the timeout expires, its
> +                                      content is set to TRUE. Otherwise, the
> +                                      value is set to FALSE. The caller can
> +                                      determine if the AP returned from Procedure
> +                                      by evaluating this value.
> +
> +  @retval EFI_SUCCESS             In blocking mode, specified AP finished before
> +                                  the timeout expires.
> +  @retval EFI_SUCCESS             In non-blocking mode, the function has been
> +                                  dispatched to specified AP.
> +  @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the
> +                                  UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
> +                                  signaled.
> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
> +  @retval EFI_TIMEOUT             In blocking mode, the timeout expired before
> +                                  the specified AP has finished.
> +  @retval EFI_NOT_READY           The specified AP is busy.
> +  @retval EFI_NOT_FOUND           The processor with the handle specified by
> +                                  ProcessorNumber does not exist.
> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP or disabled AP.
> +  @retval EFI_INVALID_PARAMETER   Procedure is NULL.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +StartupThisAP (
> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
> +  IN  EFI_AP_PROCEDURE          Procedure,
> +  IN  UINTN                     ProcessorNumber,
> +  IN  EFI_EVENT                 WaitEvent               OPTIONAL,
> +  IN  UINTN                     TimeoutInMicroseconds,
> +  IN  VOID                      *ProcedureArgument      OPTIONAL,
> +  OUT BOOLEAN                   *Finished               OPTIONAL
> +  )
> +{
> +  EFI_STATUS   Status;
> +  UINTN        Timeout;
> +  CPU_AP_DATA  *CpuData;
> +
> +  if (!IsCurrentProcessorBSP ()) {
> +    return EFI_DEVICE_ERROR;
> +  }
> +
> +  if (Procedure == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (ProcessorNumber >= mCpuMpData.NumberOfProcessors) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  CpuData = &mCpuMpData.CpuData[ProcessorNumber];
> +
> +  if (IsProcessorBSP (ProcessorNumber)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (!IsProcessorEnabled (ProcessorNumber)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (GetApState (CpuData) != CpuStateIdle) {
> +    return EFI_NOT_READY;
> +  }
> +
> +  if ((WaitEvent != NULL) && !mNonBlockingModeAllowed) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  Timeout = TimeoutInMicroseconds;
> +
> +  mCpuMpData.StartCount  = 1;
> +  mCpuMpData.FinishCount = 0;
> +
> +  SetApProcedure (
> +    CpuData,
> +    Procedure,
> +    ProcedureArgument
> +    );
> +
> +  Status = DispatchCpu (ProcessorNumber);
> +  if (EFI_ERROR (Status)) {
> +    CpuData->State = CpuStateIdle;
> +    return EFI_NOT_READY;
> +  }
> +
> +  if (WaitEvent != NULL) {
> +    // Non Blocking
> +    mCpuMpData.WaitEvent = WaitEvent;
> +    gBS->SetTimer (
> +           CpuData->CheckThisAPEvent,
> +           TimerPeriodic,
> +           POLL_INTERVAL_US
> +           );
> +    return EFI_SUCCESS;
> +  }
> +
> +  // Blocking
> +  while (TRUE) {
> +    if (GetApState (CpuData) == CpuStateFinished) {
> +      CpuData->State = CpuStateIdle;
> +      break;
> +    }
> +
> +    if ((TimeoutInMicroseconds != 0) && (Timeout == 0)) {
> +      return EFI_TIMEOUT;
> +    }
> +
> +    Timeout -= CalculateAndStallInterval (Timeout);
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  This service switches the requested AP to be the BSP from that point onward.
> +  This service changes the BSP for all purposes.   This call can only be
> +  performed by the current BSP.
> +
> +  This service switches the requested AP to be the BSP from that point onward.
> +  This service changes the BSP for all purposes. The new BSP can take over the
> +  execution of the old BSP and continue seamlessly from where the old one left
> +  off. This service may not be supported after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT
> +  is signaled.
> +
> +  If the BSP cannot be switched prior to the return from this service, then
> +  EFI_UNSUPPORTED must be returned.
> +
> +  @param[in] This              A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
> +  @param[in] ProcessorNumber   The handle number of AP that is to become the new
> +                               BSP. The range is from 0 to the total number of
> +                               logical processors minus 1. The total number of
> +                               logical processors can be retrieved by
> +                               EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
> +  @param[in] EnableOldBSP      If TRUE, then the old BSP will be listed as an
> +                               enabled AP. Otherwise, it will be disabled.
> +
> +  @retval EFI_SUCCESS             BSP successfully switched.
> +  @retval EFI_UNSUPPORTED         Switching the BSP cannot be completed prior to
> +                                  this service returning.
> +  @retval EFI_UNSUPPORTED         Switching the BSP is not supported.
> +  @retval EFI_SUCCESS             The calling processor is an AP.
> +  @retval EFI_NOT_FOUND           The processor with the handle specified by
> +                                  ProcessorNumber does not exist.
> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the current BSP or
> +                                  a disabled AP.
> +  @retval EFI_NOT_READY           The specified AP is busy.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +SwitchBSP (
> +  IN EFI_MP_SERVICES_PROTOCOL  *This,
> +  IN  UINTN                    ProcessorNumber,
> +  IN  BOOLEAN                  EnableOldBSP
> +  )
> +{
> +  return EFI_UNSUPPORTED;
> +}
> +
> +/**
> +  This service lets the caller enable or disable an AP from this point onward.
> +  This service may only be called from the BSP.
> +
> +  This service allows the caller enable or disable an AP from this point onward.
> +  The caller can optionally specify the health status of the AP by Health. If
> +  an AP is being disabled, then the state of the disabled AP is implementation
> +  dependent. If an AP is enabled, then the implementation must guarantee that a
> +  complete initialization sequence is performed on the AP, so the AP is in a state
> +  that is compatible with an MP operating system. This service may not be supported
> +  after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled.
> +
> +  If the enable or disable AP operation cannot be completed prior to the return
> +  from this service, then EFI_UNSUPPORTED must be returned.
> +
> +  @param[in] This              A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
> +  @param[in] ProcessorNumber   The handle number of AP that is to become the new
> +                               BSP. The range is from 0 to the total number of
> +                               logical processors minus 1. The total number of
> +                               logical processors can be retrieved by
> +                               EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
> +  @param[in] EnableAP          Specifies the new state for the processor for
> +                               enabled, FALSE for disabled.
> +  @param[in] HealthFlag        If not NULL, a pointer to a value that specifies
> +                               the new health status of the AP. This flag
> +                               corresponds to StatusFlag defined in
> +                               EFI_MP_SERVICES_PROTOCOL.GetProcessorInfo(). Only
> +                               the PROCESSOR_HEALTH_STATUS_BIT is used. All other
> +                               bits are ignored.  If it is NULL, this parameter
> +                               is ignored.
> +
> +  @retval EFI_SUCCESS             The specified AP was enabled or disabled successfully.
> +  @retval EFI_UNSUPPORTED         Enabling or disabling an AP cannot be completed
> +                                  prior to this service returning.
> +  @retval EFI_UNSUPPORTED         Enabling or disabling an AP is not supported.
> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
> +  @retval EFI_NOT_FOUND           Processor with the handle specified by ProcessorNumber
> +                                  does not exist.
> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +EnableDisableAP (
> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
> +  IN  UINTN                     ProcessorNumber,
> +  IN  BOOLEAN                   EnableAP,
> +  IN  UINT32                    *HealthFlag OPTIONAL
> +  )
> +{
> +  UINTN        StatusFlag;
> +  CPU_AP_DATA  *CpuData;
> +
> +  StatusFlag = mCpuMpData.CpuData[ProcessorNumber].Info.StatusFlag;
> +  CpuData    = &mCpuMpData.CpuData[ProcessorNumber];
> +
> +  if (!IsCurrentProcessorBSP ()) {
> +    return EFI_DEVICE_ERROR;
> +  }
> +
> +  if (ProcessorNumber >= mCpuMpData.NumberOfProcessors) {
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  if (IsProcessorBSP (ProcessorNumber)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (GetApState (CpuData) != CpuStateIdle) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  if (EnableAP) {
> +    if (!IsProcessorEnabled (ProcessorNumber)) {
> +      mCpuMpData.NumberOfEnabledProcessors++;
> +    }
> +
> +    StatusFlag |= PROCESSOR_ENABLED_BIT;
> +  } else {
> +    if (IsProcessorEnabled (ProcessorNumber)) {
> +      mCpuMpData.NumberOfEnabledProcessors--;
> +    }
> +
> +    StatusFlag &= ~PROCESSOR_ENABLED_BIT;
> +  }
> +
> +  if (HealthFlag != NULL) {
> +    StatusFlag &= ~PROCESSOR_HEALTH_STATUS_BIT;
> +    StatusFlag |= (*HealthFlag & PROCESSOR_HEALTH_STATUS_BIT);
> +  }
> +
> +  mCpuMpData.CpuData[ProcessorNumber].Info.StatusFlag = StatusFlag;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  This return the handle number for the calling processor.  This service may be
> +  called from the BSP and APs.
> +
> +  This service returns the processor handle number for the calling processor.
> +  The returned value is in the range from 0 to the total number of logical
> +  processors minus 1. The total number of logical processors can be retrieved
> +  with EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors(). This service may be
> +  called from the BSP and APs. If ProcessorNumber is NULL, then EFI_INVALID_PARAMETER
> +  is returned. Otherwise, the current processors handle number is returned in
> +  ProcessorNumber, and EFI_SUCCESS is returned.
> +
> +  @param[in] This              A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
> +  @param[out] ProcessorNumber  The handle number of AP that is to become the new
> +                               BSP. The range is from 0 to the total number of
> +                               logical processors minus 1. The total number of
> +                               logical processors can be retrieved by
> +                               EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
> +
> +  @retval EFI_SUCCESS             The current processor handle number was returned
> +                                  in ProcessorNumber.
> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber is NULL.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +WhoAmI (
> +  IN EFI_MP_SERVICES_PROTOCOL  *This,
> +  OUT UINTN                    *ProcessorNumber
> +  )
> +{
> +  UINTN   Index;
> +  UINT64  ProcessorId;
> +
> +  if (ProcessorNumber == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  ProcessorId = GET_MPIDR_AFFINITY_BITS (ArmReadMpidr ());
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    if (ProcessorId == gProcessorIDs[Index]) {
> +      *ProcessorNumber = Index;
> +      break;
> +    }
> +  }
> +
> +  return EFI_SUCCESS;
> +}
> +
> +STATIC EFI_MP_SERVICES_PROTOCOL  mMpServicesProtocol = {
> +  GetNumberOfProcessors,
> +  GetProcessorInfo,
> +  StartupAllAPs,
> +  StartupThisAP,
> +  SwitchBSP,
> +  EnableDisableAP,
> +  WhoAmI
> +};
> +
> +/** Adds the specified processor the list of failed processors.
> +
> +   @param ProcessorIndex The processor index to add.
> +   @param ApState        Processor state.
> +
> +**/
> +STATIC
> +VOID
> +AddProcessorToFailedList (
> +  UINTN      ProcessorIndex,
> +  CPU_STATE  ApState
> +  )
> +{
> +  UINTN    Index;
> +  BOOLEAN  Found;
> +
> +  Found = FALSE;
> +
> +  if (ApState == CpuStateIdle) {
> +    return;
> +  }
> +
> +  // If we are retrying make sure we don't double count
> +  for (Index = 0; Index < mCpuMpData.FailedListIndex; Index++) {
> +    if (mCpuMpData.FailedList[Index] == ProcessorIndex) {
> +      Found = TRUE;
> +      break;
> +    }
> +  }
> +
> +  /* If the CPU isn't already in the FailedList, add it */
> +  if (!Found) {
> +    mCpuMpData.FailedList[mCpuMpData.FailedListIndex++] = Index;
> +  }
> +}
> +
> +/** Handles the StartupAllAPs case where the timeout has occurred.
> +
> +**/
> +STATIC
> +VOID
> +ProcessStartupAllAPsTimeout (
> +  VOID
> +  )
> +{
> +  CPU_AP_DATA  *CpuData;
> +  UINTN        Index;
> +
> +  if (mCpuMpData.FailedList == NULL) {
> +    return;
> +  }
> +
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    CpuData = &mCpuMpData.CpuData[Index];
> +    if (IsProcessorBSP (Index)) {
> +      // Skip BSP
> +      continue;
> +    }
> +
> +    if (!IsProcessorEnabled (Index)) {
> +      // Skip Disabled processors
> +      continue;
> +    }
> +
> +    CpuData = &mCpuMpData.CpuData[Index];
> +    AddProcessorToFailedList (Index, GetApState (CpuData));
> +  }
> +}
> +
> +/** Updates the status of the APs.
> +
> +   @param[in] ProcessorIndex The index of the AP to update.
> +**/
> +STATIC
> +VOID
> +UpdateApStatus (
> +  IN UINTN  ProcessorIndex
> +  )
> +{
> +  EFI_STATUS   Status;
> +  CPU_AP_DATA  *CpuData;
> +  CPU_AP_DATA  *NextCpuData;
> +  CPU_STATE    State;
> +  UINTN        NextNumber;
> +
> +  CpuData = &mCpuMpData.CpuData[ProcessorIndex];
> +
> +  if (IsProcessorBSP (ProcessorIndex)) {
> +    // Skip BSP
> +    return;
> +  }
> +
> +  if (!IsProcessorEnabled (ProcessorIndex)) {
> +    // Skip Disabled processors
> +    return;
> +  }
> +
> +  State = GetApState (CpuData);
> +
> +  switch (State) {
> +    case CpuStateFinished:
> +      if (mCpuMpData.SingleThread) {
> +        Status = GetNextBlockedNumber (&NextNumber);
> +        if (!EFI_ERROR (Status)) {
> +          NextCpuData = &mCpuMpData.CpuData[NextNumber];
> +
> +          NextCpuData->State = CpuStateReady;
> +
> +          SetApProcedure (
> +            NextCpuData,
> +            mCpuMpData.Procedure,
> +            mCpuMpData.ProcedureArgument
> +            );
> +        }
> +      }
> +
> +      CpuData->State = CpuStateIdle;
> +      mCpuMpData.FinishCount++;
> +      break;
> +
> +    default:
> +      break;
> +  }
> +}
> +
> +/**
> +  If a timeout is specified in StartupAllAps(), a timer is set, which invokes
> +  this procedure periodically to check whether all APs have finished.
> +
> +  @param[in] Event   The WaitEvent the user supplied.
> +  @param[in] Context The event context.
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +CheckAllAPsStatus (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  )
> +{
> +  UINTN  Index;
> +
> +  if (mCpuMpData.TimeoutActive) {
> +    mCpuMpData.Timeout -= CalculateAndStallInterval (mCpuMpData.Timeout);
> +  }
> +
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    UpdateApStatus (Index);
> +  }
> +
> +  if (mCpuMpData.TimeoutActive && (mCpuMpData.Timeout == 0)) {
> +    ProcessStartupAllAPsTimeout ();
> +
> +    // Force terminal exit
> +    mCpuMpData.FinishCount = mCpuMpData.StartCount;
> +  }
> +
> +  if (mCpuMpData.FinishCount != mCpuMpData.StartCount) {
> +    return;
> +  }
> +
> +  gBS->SetTimer (
> +         mCpuMpData.CheckAllAPsEvent,
> +         TimerCancel,
> +         0
> +         );
> +
> +  if (mCpuMpData.FailedListIndex == 0) {
> +    if (mCpuMpData.FailedList != NULL) {
> +      FreePool (mCpuMpData.FailedList);
> +      mCpuMpData.FailedList = NULL;
> +    }
> +  }
> +
> +  gBS->SignalEvent (mCpuMpData.WaitEvent);
> +}
> +
> +/** Invoked periodically via a timer to check the state of the processor.
> +
> +   @param Event   The event supplied by the timer expiration.
> +   @param Context The processor context.
> +
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +CheckThisAPStatus (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  )
> +{
> +  EFI_STATUS   Status;
> +  CPU_AP_DATA  *CpuData;
> +  CPU_STATE    State;
> +
> +  CpuData             = Context;
> +  CpuData->TimeTaken += POLL_INTERVAL_US;
> +
> +  State = GetApState (CpuData);
> +
> +  if (State == CpuStateFinished) {
> +    Status = gBS->SetTimer (CpuData->CheckThisAPEvent, TimerCancel, 0);
> +    ASSERT_EFI_ERROR (Status);
> +
> +    if (mCpuMpData.WaitEvent != NULL) {
> +      Status = gBS->SignalEvent (mCpuMpData.WaitEvent);
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +
> +    CpuData->State = CpuStateIdle;
> +  }
> +
> +  if (CpuData->TimeTaken > CpuData->Timeout) {
> +    if (mCpuMpData.WaitEvent != NULL) {
> +      Status = gBS->SignalEvent (mCpuMpData.WaitEvent);
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +  }
> +}
> +
> +/**
> +  This function is called by all processors (both BSP and AP) once and collects
> +  MP related data.
> +
> +  @param BSP            TRUE if the processor is the BSP.
> +  @param Mpidr          The MPIDR for the specified processor. This should be
> +                        the full MPIDR and not only the affinity bits.
> +  @param ProcessorIndex The index of the processor.
> +
> +  @return EFI_SUCCESS if the data for the processor collected and filled in.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +FillInProcessorInformation (
> +  IN BOOLEAN  BSP,
> +  IN UINTN    Mpidr,
> +  IN UINTN    ProcessorIndex
> +  )
> +{
> +  EFI_PROCESSOR_INFORMATION  *CpuInfo;
> +
> +  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
> +
> +  CpuInfo->ProcessorId = GET_MPIDR_AFFINITY_BITS (Mpidr);
> +  CpuInfo->StatusFlag  = PROCESSOR_ENABLED_BIT | PROCESSOR_HEALTH_STATUS_BIT;
> +
> +  if (BSP) {
> +    CpuInfo->StatusFlag |= PROCESSOR_AS_BSP_BIT;
> +  }
> +
> +  if ((Mpidr & MPIDR_MT_BIT) > 0) {
> +    CpuInfo->Location.Package = GET_MPIDR_AFF2 (Mpidr);
> +    CpuInfo->Location.Core    = GET_MPIDR_AFF1 (Mpidr);
> +    CpuInfo->Location.Thread  = GET_MPIDR_AFF0 (Mpidr);
> +
> +    CpuInfo->ExtendedInformation.Location2.Package = GET_MPIDR_AFF3 (Mpidr);
> +    CpuInfo->ExtendedInformation.Location2.Die     = GET_MPIDR_AFF2 (Mpidr);
> +    CpuInfo->ExtendedInformation.Location2.Core    = GET_MPIDR_AFF1 (Mpidr);
> +    CpuInfo->ExtendedInformation.Location2.Thread  = GET_MPIDR_AFF0 (Mpidr);
> +  } else {
> +    CpuInfo->Location.Package = GET_MPIDR_AFF1 (Mpidr);
> +    CpuInfo->Location.Core    = GET_MPIDR_AFF0 (Mpidr);
> +    CpuInfo->Location.Thread  = 0;
> +
> +    CpuInfo->ExtendedInformation.Location2.Package = GET_MPIDR_AFF2 (Mpidr);
> +    CpuInfo->ExtendedInformation.Location2.Die     = GET_MPIDR_AFF1 (Mpidr);
> +    CpuInfo->ExtendedInformation.Location2.Core    = GET_MPIDR_AFF0 (Mpidr);
> +    CpuInfo->ExtendedInformation.Location2.Thread  = 0;
> +  }
> +
> +  mCpuMpData.CpuData[ProcessorIndex].State = BSP ? CpuStateBusy : CpuStateIdle;
> +
> +  mCpuMpData.CpuData[ProcessorIndex].Procedure = NULL;
> +  mCpuMpData.CpuData[ProcessorIndex].Parameter = NULL;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/** Initializes the MP Services system data
> +
> +   @param NumberOfProcessors The number of processors, both BSP and AP.
> +   @param CoreInfo           CPU information gathered earlier during boot.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +MpServicesInitialize (
> +  IN   UINTN                NumberOfProcessors,
> +  IN   CONST ARM_CORE_INFO  *CoreInfo
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINTN       Index;
> +  EFI_EVENT   ReadyToBootEvent;
> +  BOOLEAN     IsBsp;
[KQ]: Can we add a check to see if BSP is found during this routine? I 
think failing to identify a BSP might cause other issues in the 
following services?
> +
> +  //
> +  // Clear the data structure area first.
> +  //
> +  ZeroMem (&mCpuMpData, sizeof (CPU_MP_DATA));
> +  //
> +  // First BSP fills and inits all known values, including its own records.
> +  //
> +  mCpuMpData.NumberOfProcessors        = NumberOfProcessors;
> +  mCpuMpData.NumberOfEnabledProcessors = NumberOfProcessors;
> +
> +  mCpuMpData.CpuData = AllocateZeroPool (
> +                         mCpuMpData.NumberOfProcessors * sizeof (CPU_AP_DATA)
> +                         );
> +
> +  if (mCpuMpData.CpuData == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  /* Allocate one extra for the sentinel entry at the end */
> +  gProcessorIDs = AllocatePool ((mCpuMpData.NumberOfProcessors + 1) * sizeof (UINT64));
> +  ASSERT (gProcessorIDs != NULL);
> +
> +  Status = gBS->CreateEvent (
> +                  EVT_TIMER | EVT_NOTIFY_SIGNAL,
> +                  TPL_CALLBACK,
> +                  CheckAllAPsStatus,
> +                  NULL,
> +                  &mCpuMpData.CheckAllAPsEvent
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  gApStacksBase = AllocatePages (
> +                    EFI_SIZE_TO_PAGES (
> +                      mCpuMpData.NumberOfProcessors *
> +                      gApStackSize
> +                      )
> +                    );
> +  ASSERT (gApStacksBase != NULL);
> +
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    if (GET_MPIDR_AFFINITY_BITS (ArmReadMpidr ()) == CoreInfo[Index].Mpidr) {
[KQ]: Does this mean BSP should never set the `MPIDR_MT_BIT` in the 
gArmMpCoreInfoGuid HOB data? Otherwise, this logic will never be able to 
find the BSP?
> +      IsBsp = TRUE;
> +    } else {
> +      IsBsp = FALSE;
> +    }
> +
> +    FillInProcessorInformation (IsBsp, CoreInfo[Index].Mpidr, Index);
> +
> +    gProcessorIDs[Index] = mCpuMpData.CpuData[Index].Info.ProcessorId;
> +
> +    Status = gBS->CreateEvent (
> +                    EVT_TIMER | EVT_NOTIFY_SIGNAL,
> +                    TPL_CALLBACK,
> +                    CheckThisAPStatus,
> +                    (VOID *)&mCpuMpData.CpuData[Index],
> +                    &mCpuMpData.CpuData[Index].CheckThisAPEvent
> +                    );
> +    ASSERT_EFI_ERROR (Status);
> +  }
> +
> +  gProcessorIDs[Index] = MAX_UINT64;
> +
> +  //
> +  // The global pointer variables as well as the gProcessorIDs array contents
> +  // are accessed by the other cores so we must clean them to the PoC
> +  //
> +  WriteBackDataCacheRange (&gProcessorIDs, sizeof (UINT64 *));
> +  WriteBackDataCacheRange (&gApStacksBase, sizeof (UINT64 *));
> +
> +  WriteBackDataCacheRange (
> +    gProcessorIDs,
> +    (mCpuMpData.NumberOfProcessors + 1) * sizeof (UINT64)
> +    );
> +
> +  Status = EfiCreateEventReadyToBootEx (
> +             TPL_CALLBACK,
> +             ReadyToBootSignaled,
> +             NULL,
> +             &ReadyToBootEvent
> +             );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Event notification function called when the EFI_EVENT_GROUP_READY_TO_BOOT is
> +  signaled. After this point, non-blocking mode is no longer allowed.
> +
> +  @param  Event     Event whose notification function is being invoked.
> +  @param  Context   The pointer to the notification function's context,
> +                    which is implementation-dependent.
> +
> +**/
> +STATIC
> +VOID
> +EFIAPI
> +ReadyToBootSignaled (
> +  IN  EFI_EVENT  Event,
> +  IN  VOID       *Context
> +  )
> +{
> +  mNonBlockingModeAllowed = FALSE;
> +}
> +
> +/** Initialize multi-processor support.
> +
> +  @param ImageHandle  Image handle.
> +  @param SystemTable  System table.
> +
> +  @return EFI_SUCCESS on success, or an error code.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +ArmPsciMpServicesDxeInitialize (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS                 Status;
> +  EFI_HANDLE                 Handle;
> +  UINTN                      MaxCpus;
> +  EFI_LOADED_IMAGE_PROTOCOL  *Image;
> +  EFI_HOB_GENERIC_HEADER     *Hob;
> +  VOID                       *HobData;
> +  UINTN                      HobDataSize;
> +  CONST ARM_CORE_INFO        *CoreInfo;
> +
> +  MaxCpus = 1;
> +
> +  DEBUG ((DEBUG_INFO, "Starting MP services\n"));
> +
> +  Status = gBS->HandleProtocol (
> +                  ImageHandle,
> +                  &gEfiLoadedImageProtocolGuid,
> +                  (VOID **)&Image
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Parts of the code in this driver may be executed by other cores running
> +  // with the MMU off so we need to ensure that everything is clean to the
> +  // point of coherency (PoC)
> +  //
> +  WriteBackDataCacheRange (Image->ImageBase, Image->ImageSize);
> +
> +  Status = gBS->HandleProtocol (
> +                  ImageHandle,
> +                  &gEfiLoadedImageProtocolGuid,
> +                  (VOID **)&Image
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +
> +  //
> +  // Parts of the code in this driver may be executed by other cores running
> +  // with the MMU off so we need to ensure that everything is clean to the
> +  // point of coherency (PoC)
> +  //
> +  WriteBackDataCacheRange (Image->ImageBase, Image->ImageSize);
> +
> +  Hob = GetFirstGuidHob (&gArmMpCoreInfoGuid);
> +  if (Hob != NULL) {
> +    HobData     = GET_GUID_HOB_DATA (Hob);
> +    HobDataSize = GET_GUID_HOB_DATA_SIZE (Hob);
> +    CoreInfo    = (ARM_CORE_INFO *)HobData;
> +    MaxCpus     = HobDataSize / sizeof (ARM_CORE_INFO);
> +  }
> +
> +  if (MaxCpus == 1) {
> +    DEBUG ((DEBUG_WARN, "Trying to use EFI_MP_SERVICES_PROTOCOL on a UP system"));
> +    // We are not MP so nothing to do
> +    return EFI_NOT_FOUND;
> +  }
> +
> +  Status = MpServicesInitialize (MaxCpus, CoreInfo);
> +  if (Status != EFI_SUCCESS) {
> +    ASSERT_EFI_ERROR (Status);
> +    return Status;
> +  }
> +
> +  //
> +  // Now install the MP services protocol.
> +  //
> +  Handle = NULL;
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +                  &Handle,
> +                  &gEfiMpServiceProtocolGuid,
> +                  &mMpServicesProtocol,
> +                  NULL
> +                  );
> +  ASSERT_EFI_ERROR (Status);
> +  return Status;
> +}
> +
> +/** C entry-point for the AP.
> +    This function gets called from the assembly function ApEntryPoint.
> +
> +**/
> +VOID
> +ApProcedure (
> +  VOID
> +  )
> +{
> +  ARM_SMC_ARGS      Args;
> +  EFI_AP_PROCEDURE  UserApProcedure;
> +  VOID              *UserApParameter;
> +  UINTN             ProcessorIndex;
> +
> +  WhoAmI (&mMpServicesProtocol, &ProcessorIndex);
> +
> +  /* Fetch the user-supplied procedure and parameter to execute */
> +  UserApProcedure = mCpuMpData.CpuData[ProcessorIndex].Procedure;
> +  UserApParameter = mCpuMpData.CpuData[ProcessorIndex].Parameter;
> +
> +  // Configure the MMU and caches
> +  ArmSetTCR (mCpuMpData.CpuData[ProcessorIndex].Tcr);
> +  ArmSetTTBR0 (mCpuMpData.CpuData[ProcessorIndex].Ttbr0);
> +  ArmSetMAIR (mCpuMpData.CpuData[ProcessorIndex].Mair);
> +  ArmDisableAlignmentCheck ();
> +  ArmEnableStackAlignmentCheck ();
> +  ArmEnableInstructionCache ();
> +  ArmEnableDataCache ();
> +  ArmEnableMmu ();
> +
> +  UserApProcedure (UserApParameter);
> +
> +  mCpuMpData.CpuData[ProcessorIndex].State = CpuStateFinished;
> +
> +  ArmDataMemoryBarrier ();
> +
> +  /* Since we're finished with this AP, turn it off */
> +  Args.Arg0 = ARM_SMC_ID_PSCI_CPU_OFF;
> +  ArmCallSmc (&Args);
> +
> +  /* Should never be reached */
> +  ASSERT (FALSE);
> +  CpuDeadLoop ();
> +}
> +
> +/** Returns whether the processor executing this function is the BSP.
> +
> +    @return Whether the current processor is the BSP.
> +**/
> +STATIC
> +BOOLEAN
> +IsCurrentProcessorBSP (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINTN       ProcessorIndex;
> +
> +  Status = WhoAmI (&mMpServicesProtocol, &ProcessorIndex);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT_EFI_ERROR (Status);
> +    return FALSE;
> +  }
> +
> +  return IsProcessorBSP (ProcessorIndex);
> +}
> +
> +/** Returns whether the specified processor is enabled.
> +
> +   @param[in] ProcessorIndex The index of the processor to check.
> +
> +   @return TRUE if the processor is enabled, FALSE otherwise.
> +**/
> +STATIC
> +BOOLEAN
> +IsProcessorEnabled (
> +  UINTN  ProcessorIndex
> +  )
> +{
> +  EFI_PROCESSOR_INFORMATION  *CpuInfo;
> +
> +  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
> +
> +  return (CpuInfo->StatusFlag & PROCESSOR_ENABLED_BIT) != 0;
> +}
> +
> +/** Returns whether all processors are in the idle state.
> +
> +   @return Whether all the processors are idle.
> +
> +**/
> +STATIC
> +BOOLEAN
> +CheckAllCpusReady (
> +  VOID
> +  )
> +{
> +  UINTN        Index;
> +  CPU_AP_DATA  *CpuData;
> +
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    CpuData = &mCpuMpData.CpuData[Index];
> +    if (IsProcessorBSP (Index)) {
> +      // Skip BSP
> +      continue;
> +    }
> +
> +    if (!IsProcessorEnabled (Index)) {
> +      // Skip Disabled processors
> +      continue;
> +    }
> +
> +    if (GetApState (CpuData) != CpuStateIdle) {
> +      return FALSE;
> +    }
> +  }
> +
> +  return TRUE;
> +}
> +
> +/** Sets up the state for the StartupAllAPs function.
> +
> +   @param SingleThread Whether the APs will execute sequentially.
> +
> +**/
> +STATIC
> +VOID
> +StartupAllAPsPrepareState (
> +  IN BOOLEAN  SingleThread
> +  )
> +{
> +  UINTN        Index;
> +  CPU_STATE    APInitialState;
> +  CPU_AP_DATA  *CpuData;
> +
> +  mCpuMpData.FinishCount  = 0;
> +  mCpuMpData.StartCount   = 0;
> +  mCpuMpData.SingleThread = SingleThread;
> +
> +  APInitialState = CpuStateReady;
> +
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    CpuData = &mCpuMpData.CpuData[Index];
> +
> +    //
> +    // Get APs prepared, and put failing APs into FailedCpuList.
> +    // If "SingleThread", only 1 AP will put into ready state, other AP will be
> +    // put into ready state 1 by 1, until the previous 1 finished its task.
> +    // If not "SingleThread", all APs are put into ready state from the
> +    // beginning
> +    //
> +
> +    if (IsProcessorBSP (Index)) {
> +      // Skip BSP
> +      continue;
> +    }
> +
> +    if (!IsProcessorEnabled (Index)) {
> +      // Skip Disabled processors
> +      if (mCpuMpData.FailedList != NULL) {
> +        mCpuMpData.FailedList[mCpuMpData.FailedListIndex++] = Index;
> +      }
> +
> +      continue;
> +    }
> +
> +    ASSERT (GetApState (CpuData) == CpuStateIdle);
> +    CpuData->State = APInitialState;
> +
> +    mCpuMpData.StartCount++;
> +    if (SingleThread) {
> +      APInitialState = CpuStateBlocked;
> +    }
> +  }
> +}
> +
> +/** Handles execution of StartupAllAPs when a WaitEvent has been specified.
> +
> +   @param Procedure         The user-supplied procedure.
> +   @param ProcedureArgument The user-supplied procedure argument.
> +   @param WaitEvent         The wait event to be signaled when the work is
> +                            complete or a timeout has occurred.
> +   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
> +                                indicates an infinite timeout.
> +
> +   @return EFI_SUCCESS on success.
> +**/
> +STATIC
> +EFI_STATUS
> +StartupAllAPsWithWaitEvent (
> +  IN EFI_AP_PROCEDURE  Procedure,
> +  IN VOID              *ProcedureArgument,
> +  IN EFI_EVENT         WaitEvent,
> +  IN UINTN             TimeoutInMicroseconds
> +  )
> +{
> +  EFI_STATUS   Status;
> +  UINTN        Index;
> +  CPU_AP_DATA  *CpuData;
> +
> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +    CpuData = &mCpuMpData.CpuData[Index];
> +    if (IsProcessorBSP (Index)) {
> +      // Skip BSP
> +      continue;
> +    }
> +
> +    if (!IsProcessorEnabled (Index)) {
> +      // Skip Disabled processors
> +      continue;
> +    }
> +
> +    if (GetApState (CpuData) == CpuStateReady) {
> +      SetApProcedure (CpuData, Procedure, ProcedureArgument);
> +    }
> +  }
> +
> +  //
> +  // Save data into private data structure, and create timer to poll AP state
> +  // before exiting
> +  //
> +  mCpuMpData.Procedure         = Procedure;
> +  mCpuMpData.ProcedureArgument = ProcedureArgument;
> +  mCpuMpData.WaitEvent         = WaitEvent;
> +  mCpuMpData.Timeout           = TimeoutInMicroseconds;
> +  mCpuMpData.TimeoutActive     = (BOOLEAN)(TimeoutInMicroseconds != 0);
> +  Status                       = gBS->SetTimer (
> +                                        mCpuMpData.CheckAllAPsEvent,
> +                                        TimerPeriodic,
> +                                        POLL_INTERVAL_US
> +                                        );
> +  return Status;
> +}
> +
> +/** Handles execution of StartupAllAPs when no wait event has been specified.
> +
> +   @param Procedure             The user-supplied procedure.
> +   @param ProcedureArgument     The user-supplied procedure argument.
> +   @param TimeoutInMicroseconds The timeout for the work to be completed. Zero
> +                                indicates an infinite timeout.
> +   @param SingleThread          Whether the APs will execute sequentially.
> +   @param FailedCpuList         User-supplied pointer for list of failed CPUs.
> +
> +   @return EFI_SUCCESS on success.
> +**/
> +STATIC
> +EFI_STATUS
> +StartupAllAPsNoWaitEvent (
> +  IN EFI_AP_PROCEDURE  Procedure,
> +  IN VOID              *ProcedureArgument,
> +  IN UINTN             TimeoutInMicroseconds,
> +  IN BOOLEAN           SingleThread,
> +  IN UINTN             **FailedCpuList
> +  )
> +{
> +  EFI_STATUS   Status;
> +  UINTN        Index;
> +  UINTN        NextIndex;
> +  UINTN        Timeout;
> +  CPU_AP_DATA  *CpuData;
> +
> +  Timeout = TimeoutInMicroseconds;
> +
> +  while (TRUE) {
> +    for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
> +      CpuData = &mCpuMpData.CpuData[Index];
> +      if (IsProcessorBSP (Index)) {
> +        // Skip BSP
> +        continue;
> +      }
> +
> +      if (!IsProcessorEnabled (Index)) {
> +        // Skip Disabled processors
> +        continue;
> +      }
> +
> +      switch (GetApState (CpuData)) {
> +        case CpuStateReady:
> +          SetApProcedure (CpuData, Procedure, ProcedureArgument);
> +          Status = DispatchCpu (Index);
> +          if (EFI_ERROR (Status)) {
> +            CpuData->State = CpuStateIdle;
> +            Status         = EFI_NOT_READY;
> +            goto Done;
[KQ]: Is it really necessary to use "goto Done"? This might cause all 
the CPUs after this failing index to not reset the CPU state.
That way, all the subsequent "StartupAllAps" will fail due to 
"CheckAllCpusReady" returning FALSE on those "dirty cores". Please
let me know if that is by design or not.
> +          }
> +
> +          break;
> +
> +        case CpuStateFinished:
> +          mCpuMpData.FinishCount++;
> +          if (SingleThread) {
> +            Status = GetNextBlockedNumber (&NextIndex);
> +            if (!EFI_ERROR (Status)) {
> +              mCpuMpData.CpuData[NextIndex].State = CpuStateReady;
> +            }
> +          }
> +
> +          CpuData->State = CpuStateIdle;
> +          break;
> +
> +        default:
> +          break;
> +      }
> +    }
> +
> +    if (mCpuMpData.FinishCount == mCpuMpData.StartCount) {
> +      Status = EFI_SUCCESS;
> +      goto Done;
> +    }
> +
> +    if ((TimeoutInMicroseconds != 0) && (Timeout == 0)) {
> +      Status = EFI_TIMEOUT;
> +      goto Done;
> +    }
> +
> +    Timeout -= CalculateAndStallInterval (Timeout);
> +  }
> +
> +Done:
> +  if (FailedCpuList != NULL) {
> +    if (mCpuMpData.FailedListIndex == 0) {
> +      FreePool (*FailedCpuList);
> +      *FailedCpuList = NULL;
> +    }
> +  }
> +
> +  return Status;
> +}
> diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S
> new file mode 100644
> index 000000000000..a90fa8a0075f
> --- /dev/null
> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S
> @@ -0,0 +1,57 @@
> +#===============================================================================
> +#  Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#===============================================================================
> +
> +.text
> +.align 3
> +
> +#include <AsmMacroIoLibV8.h>
> +#include <IndustryStandard/ArmStdSmc.h>
> +
> +#include "MpServicesInternal.h"
> +
> +GCC_ASM_IMPORT (gApStacksBase)
> +GCC_ASM_IMPORT (gProcessorIDs)
> +GCC_ASM_IMPORT (ApProcedure)
> +GCC_ASM_IMPORT (gApStackSize)
> +
> +GCC_ASM_EXPORT (ApEntryPoint)
> +
> +// Entry-point for the AP
> +// VOID
> +// ApEntryPoint (
> +//   VOID
> +//   );
> +ASM_PFX(ApEntryPoint):
> +  mrs x0, mpidr_el1
> +  // Mask the non-affinity bits
> +  bic x0, x0, 0x00ff000000
> +  and x0, x0, 0xffffffffff
> +  ldr x1, gProcessorIDs
> +  mov x2, 0                   // x2 = processor index
> +
> +// Find index in gProcessorIDs for current processor
> +1:
> +  ldr x3, [x1, x2, lsl #3]    // x4 = gProcessorIDs + x2 * 8
> +  cmp x3, #-1                 // check if we've reached the end of gProcessorIDs
> +  beq ProcessorNotFound
> +  add x2, x2, 1               // x2++
> +  cmp x0, x3                  // if mpidr_el1 != gProcessorIDs[x] then loop
> +  bne 1b
> +
> +// Calculate stack address
> +  // x2 contains the index for the current processor plus 1
> +  ldr x0, gApStacksBase
> +  ldr x1, gApStackSize
> +  mul x3, x2, x1              // x3 = (ProcessorIndex + 1) * gApStackSize
> +  add sp, x0, x3              // sp = gApStacksBase + x3
> +  mov x29, xzr
> +  bl ApProcedure              // doesn't return
> +
> +ProcessorNotFound:
> +// Turn off the processor
> +  MOV32 (w0, ARM_SMC_ID_PSCI_CPU_OFF)
> +  smc #0
> +  b .

Re: [edk2-devel] [PATCH 1/2] ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls

[Kun Qin]

Hi Rebecca/Ard,

I was trying to reach out regarding the original patches earlier (see 
below) but it might fell off your stacks
due to high traffic on the mailing list. Could you please kindly review 
the questions when you have a chance?

In addition, I found another edge case of the MP service: when the AP 
routine hits a timeout, the metadata
will be left in the unfinished states. If the AP routine eventually 
completes and return, this AP will stay in "finished"
but never become "ready" during this boot. I tried to add below change, 
which seems to work. But please let me
know if you have other concerns:
https://github.com/kuqin12/mu_silicon_arm_tiano/commit/c76072b37018276f2fec2582d0c540be5b40d0f2

Lastly, do you plan to merge these patches in the near future? This will 
be a great add-on for ARM platforms.

Thanks,
Kun

On 9/29/2022 11:45 AM, Kun Qin wrote:
> Hi Rebecca,
>
> Thanks for sending this patch. I have a few questions inline "[KQ]". 
> Could you please help me to
> understand the patch better? Thanks in advance.
>
> Regards,
> Kun
>
> On 8/29/2022 8:59 AM, Rebecca Cran wrote:
>> Add support for EFI_MP_SERVICES_PROTOCOL during the DXE phase under
>> AArch64.
>>
>> PSCI_CPU_ON is called to power on the core, the supplied procedure is
>> executed and PSCI_CPU_OFF is called to power off the core.
>>
>> Fixes contributed by Ard Biesheuvel.
>>
>> Signed-off-by: Rebecca Cran <rebecca@quicinc.com>
>> ---
>>   ArmPkg/ArmPkg.dsc |    1 +
>>   ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf |   55 +
>>   ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h |  351 ++++
>>   ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c   | 1774 
>> ++++++++++++++++++++
>>   ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S |   57 +
>>   5 files changed, 2238 insertions(+)
>>
>> diff --git a/ArmPkg/ArmPkg.dsc b/ArmPkg/ArmPkg.dsc
>> index 59fd8f295d4f..4716789402fc 100644
>> --- a/ArmPkg/ArmPkg.dsc
>> +++ b/ArmPkg/ArmPkg.dsc
>> @@ -125,6 +125,7 @@ [Components.common]
>>     ArmPkg/Drivers/CpuPei/CpuPei.inf
>>     ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
>>     ArmPkg/Drivers/ArmGic/ArmGicLib.inf
>> +  ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
>>     ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.inf
>>     ArmPkg/Drivers/TimerDxe/TimerDxe.inf
>>   diff --git 
>> a/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf 
>> b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
>> new file mode 100644
>> index 000000000000..2b109c72e0a0
>> --- /dev/null
>> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
>> @@ -0,0 +1,55 @@
>> +## @file
>> +#  ARM MP services protocol driver
>> +#
>> +#  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights 
>> reserved.<BR>
>> +#
>> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
>> +#
>> +##
>> +
>> +[Defines]
>> +  INF_VERSION                    = 1.27
>> +  BASE_NAME                      = ArmPsciMpServicesDxe
>> +  FILE_GUID                      = 007ab472-dc4a-4df8-a5c2-abb4a327278c
>> +  MODULE_TYPE                    = DXE_DRIVER
>> +  VERSION_STRING                 = 1.0
>> +
>> +  ENTRY_POINT                    = ArmPsciMpServicesDxeInitialize
>> +
>> +[Sources.Common]
>> +  ArmPsciMpServicesDxe.c
>> +  MpFuncs.S
>> +  MpServicesInternal.h
>> +
>> +[Packages]
>> +  ArmPkg/ArmPkg.dec
>> +  ArmPlatformPkg/ArmPlatformPkg.dec
>> +  EmbeddedPkg/EmbeddedPkg.dec
>> +  MdePkg/MdePkg.dec
>> +  MdeModulePkg/MdeModulePkg.dec
>> +
>> +[LibraryClasses]
>> +  ArmLib
>> +  ArmMmuLib
>> +  ArmSmcLib
>> +  BaseMemoryLib
>> +  CacheMaintenanceLib
>> +  DebugLib
>> +  HobLib
>> +  MemoryAllocationLib
>> +  UefiBootServicesTableLib
>> +  UefiDriverEntryPoint
>> +  UefiLib
>> +
>> +[Protocols]
>> +  gEfiMpServiceProtocolGuid            ## PRODUCES
>> +  gEfiLoadedImageProtocolGuid          ## CONSUMES
>> +
>> +[Guids]
>> +  gArmMpCoreInfoGuid
>> +
>> +[Depex]
>> +  TRUE
>> +
>> +[BuildOptions]
>> +  GCC:*_*_*_CC_FLAGS = -mstrict-align
>> diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h 
>> b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
>> new file mode 100644
>> index 000000000000..ee13816ef64c
>> --- /dev/null
>> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
>> @@ -0,0 +1,351 @@
>> +/** @file
>> +
>> +Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights 
>> reserved.<BR>
>> +Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
>> +Portions copyright (c) 2011, Apple Inc. All rights reserved.
>> +
>> +SPDX-License-Identifier: BSD-2-Clause-Patent
>> +
>> +**/
>> +
>> +#ifndef MP_SERVICES_INTERNAL_H_
>> +#define MP_SERVICES_INTERNAL_H_
>> +
>> +#include <Protocol/Cpu.h>
>> +#include <Protocol/MpService.h>
>> +
>> +#include <Library/BaseLib.h>
>> +#include <Library/UefiLib.h>
>> +
>> +#define AP_STACK_SIZE  0x1000
>> +
>> +//
>> +// Internal Data Structures
>> +//
>> +
>> +//
>> +// AP state
>> +//
>> +// The state transitions for an AP when it process a procedure are:
>> +//  Idle ----> Ready ----> Busy ----> Idle
>> +//       [BSP]       [AP]       [AP]
>> +//
>> +typedef enum {
>> +  CpuStateIdle,
>> +  CpuStateReady,
>> +  CpuStateBlocked,
>> +  CpuStateBusy,
>> +  CpuStateFinished,
>> +  CpuStateDisabled
>> +} CPU_STATE;
>> +
>> +//
>> +// Define Individual Processor Data block.
>> +//
>> +typedef struct {
>> +  EFI_PROCESSOR_INFORMATION    Info;
>> +  EFI_AP_PROCEDURE             Procedure;
>> +  VOID                         *Parameter;
>> +  CPU_STATE                    State;
>> +  EFI_EVENT                    CheckThisAPEvent;
>> +  UINTN                        Timeout;
>> +  UINTN                        TimeTaken;
>> +  VOID                         *Ttbr0;
>> +  UINTN                        Tcr;
>> +  UINTN                        Mair;
>> +} CPU_AP_DATA;
>> +
>> +//
>> +// Define MP data block which consumes individual processor block.
>> +//
>> +typedef struct {
>> +  UINTN               NumberOfProcessors;
>> +  UINTN               NumberOfEnabledProcessors;
>> +  EFI_EVENT           CheckAllAPsEvent;
>> +  EFI_EVENT           WaitEvent;
>> +  UINTN               FinishCount;
>> +  UINTN               StartCount;
>> +  EFI_AP_PROCEDURE    Procedure;
>> +  VOID                *ProcedureArgument;
>> +  BOOLEAN             SingleThread;
>> +  UINTN               StartedNumber;
>> +  CPU_AP_DATA         *CpuData;
>> +  UINTN               Timeout;
>> +  UINTN               *FailedList;
>> +  UINTN               FailedListIndex;
>> +  BOOLEAN             TimeoutActive;
>> +} CPU_MP_DATA;
>> +
>> +/** Secondary core entry point.
>> +
>> +**/
>> +VOID
>> +ApEntryPoint (
>> +  VOID
>> +  );
>> +
>> +/** C entry-point for the AP.
>> +    This function gets called from the assembly function ApEntryPoint.
>> +**/
>> +VOID
>> +ApProcedure (
>> +  VOID
>> +  );
>> +
>> +/** Turns on the specified core using PSCI and executes the 
>> user-supplied
>> +    function that's been configured via a previous call to 
>> SetApProcedure.
>> +
>> +   @param ProcessorIndex The index of the core to turn on.
>> +
>> +   @retval EFI_SUCCESS       The processor was successfully turned on.
>> +   @retval EFI_DEVICE_ERROR  An error occurred turning the processor 
>> on.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +DispatchCpu (
>> +  IN UINTN  ProcessorIndex
>> +  );
>> +
>> +/** Returns whether the specified processor is the BSP.
>> +
>> +   @param[in] ProcessorIndex The index the processor to check.
>> +
>> +   @return TRUE if the processor is the BSP, FALSE otherwise.
>> +**/
>> +STATIC
>> +BOOLEAN
>> +IsProcessorBSP (
>> +  UINTN  ProcessorIndex
>> +  );
>> +
>> +/** Returns whether the processor executing this function is the BSP.
>> +
>> +   @return Whether the current processor is the BSP.
>> +**/
>> +STATIC
>> +BOOLEAN
>> +IsCurrentProcessorBSP (
>> +  VOID
>> +  );
>> +
>> +/** Returns whether the specified processor is enabled.
>> +
>> +   @param[in] ProcessorIndex The index of the processor to check.
>> +
>> +   @return TRUE if the processor is enabled, FALSE otherwise.
>> +**/
>> +STATIC
>> +BOOLEAN
>> +IsProcessorEnabled (
>> +  UINTN  ProcessorIndex
>> +  );
>> +
>> +/** Configures the processor context with the user-supplied 
>> procedure and
>> +    argument.
>> +
>> +   @param CpuData           The processor context.
>> +   @param Procedure         The user-supplied procedure.
>> +   @param ProcedureArgument The user-supplied procedure argument.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +SetApProcedure (
>> +  IN   CPU_AP_DATA       *CpuData,
>> +  IN   EFI_AP_PROCEDURE  Procedure,
>> +  IN   VOID              *ProcedureArgument
>> +  );
>> +
>> +/**
>> +  Get the Application Processors state.
>> +
>> +  @param[in]  CpuData    The pointer to CPU_AP_DATA of specified AP
>> +
>> +  @return  The AP status
>> +**/
>> +CPU_STATE
>> +GetApState (
>> +  IN  CPU_AP_DATA  *CpuData
>> +  );
>> +
>> +/** Returns the index of the next processor that is blocked.
>> +
>> +   @param[out] NextNumber The index of the next blocked processor.
>> +
>> +   @retval EFI_SUCCESS   Successfully found the next blocked processor.
>> +   @retval EFI_NOT_FOUND There are no blocked processors.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +GetNextBlockedNumber (
>> +  OUT UINTN  *NextNumber
>> +  );
>> +
>> +/** Stalls the BSP for the minimum of gPollInterval and Timeout.
>> +
>> +   @param[in]  Timeout    The time limit in microseconds remaining for
>> +                          APs to return from Procedure.
>> +
>> +   @retval     StallTime  Time of execution stall.
>> +**/
>> +STATIC
>> +UINTN
>> +CalculateAndStallInterval (
>> +  IN UINTN  Timeout
>> +  );
>> +
>> +/** Returns whether all processors are in the idle state.
>> +
>> +   @return Whether all the processors are idle.
>> +
>> +**/
>> +STATIC
>> +BOOLEAN
>> +CheckAllCpusReady (
>> +  VOID
>> +  );
>> +
>> +/** Sets up the state for the StartupAllAPs function.
>> +
>> +   @param SingleThread Whether the APs will execute sequentially.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +StartupAllAPsPrepareState (
>> +  IN BOOLEAN  SingleThread
>> +  );
>> +
>> +/** Handles execution of StartupAllAPs when a WaitEvent has been 
>> specified.
>> +
>> +   @param Procedure         The user-supplied procedure.
>> +   @param ProcedureArgument The user-supplied procedure argument.
>> +   @param WaitEvent         The wait event to be signaled when the 
>> work is
>> +                            complete or a timeout has occurred.
>> +   @param TimeoutInMicroseconds The timeout for the work to be 
>> completed. Zero
>> +                                indicates an infinite timeout.
>> +
>> +   @return EFI_SUCCESS on success.
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +StartupAllAPsWithWaitEvent (
>> +  IN EFI_AP_PROCEDURE  Procedure,
>> +  IN VOID              *ProcedureArgument,
>> +  IN EFI_EVENT         WaitEvent,
>> +  IN UINTN             TimeoutInMicroseconds
>> +  );
>> +
>> +/** Handles execution of StartupAllAPs when no wait event has been 
>> specified.
>> +
>> +   @param Procedure             The user-supplied procedure.
>> +   @param ProcedureArgument     The user-supplied procedure argument.
>> +   @param TimeoutInMicroseconds The timeout for the work to be 
>> completed. Zero
>> +                                indicates an infinite timeout.
>> +   @param SingleThread          Whether the APs will execute 
>> sequentially.
>> +   @param FailedCpuList         User-supplied pointer for list of 
>> failed CPUs.
>> +
>> +   @return EFI_SUCCESS on success.
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +StartupAllAPsNoWaitEvent (
>> +  IN EFI_AP_PROCEDURE  Procedure,
>> +  IN VOID              *ProcedureArgument,
>> +  IN UINTN             TimeoutInMicroseconds,
>> +  IN BOOLEAN           SingleThread,
>> +  IN UINTN             **FailedCpuList
>> +  );
>> +
>> +/** Adds the specified processor the list of failed processors.
>> +
>> +   @param ProcessorIndex The processor index to add.
>> +   @param ApState         Processor state.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +AddProcessorToFailedList (
>> +  UINTN      ProcessorIndex,
>> +  CPU_STATE  ApState
>> +  );
>> +
>> +/** Handles the StartupAllAPs case where the timeout has occurred.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +ProcessStartupAllAPsTimeout (
>> +  VOID
>> +  );
>> +
>> +/**
>> +  If a timeout is specified in StartupAllAps(), a timer is set, 
>> which invokes
>> +  this procedure periodically to check whether all APs have finished.
>> +
>> +  @param[in] Event   The WaitEvent the user supplied.
>> +  @param[in] Context The event context.
>> +**/
>> +STATIC
>> +VOID
>> +EFIAPI
>> +CheckAllAPsStatus (
>> +  IN  EFI_EVENT  Event,
>> +  IN  VOID       *Context
>> +  );
>> +
>> +/** Invoked periodically via a timer to check the state of the 
>> processor.
>> +
>> +   @param Event   The event supplied by the timer expiration.
>> +   @param Context The processor context.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +EFIAPI
>> +CheckThisAPStatus (
>> +  IN  EFI_EVENT  Event,
>> +  IN  VOID       *Context
>> +  );
>> +
>> +/**
>> +  This function is called by all processors (both BSP and AP) once 
>> and collects
>> +  MP related data.
>> +
>> +  @param BSP            TRUE if the processor is the BSP.
>> +  @param Mpidr          The MPIDR for the specified processor. This 
>> should be
>> +                        the full MPIDR and not only the affinity bits.
>> +  @param ProcessorIndex The index of the processor.
>> +
>> +  @return EFI_SUCCESS if the data for the processor collected and 
>> filled in.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +FillInProcessorInformation (
>> +  IN BOOLEAN  BSP,
>> +  IN UINTN    Mpidr,
>> +  IN UINTN    ProcessorIndex
>> +  );
>> +
>> +/**
>> +  Event notification function called when the 
>> EFI_EVENT_GROUP_READY_TO_BOOT is
>> +  signaled. After this point, non-blocking mode is no longer allowed.
>> +
>> +  @param  Event     Event whose notification function is being invoked.
>> +  @param  Context   The pointer to the notification function's context,
>> +                    which is implementation-dependent.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +EFIAPI
>> +ReadyToBootSignaled (
>> +  IN  EFI_EVENT  Event,
>> +  IN  VOID       *Context
>> +  );
>> +
>> +#endif /* MP_SERVICES_INTERNAL_H_ */
>> diff --git 
>> a/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c 
>> b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
>> new file mode 100644
>> index 000000000000..8cea203c7e34
>> --- /dev/null
>> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
>> @@ -0,0 +1,1774 @@
>> +/** @file
>> +  Construct MP Services Protocol.
>> +
>> +  The MP Services Protocol provides a generalized way of performing 
>> following tasks:
>> +    - Retrieving information of multi-processor environment and 
>> MP-related status of
>> +      specific processors.
>> +    - Dispatching user-provided function to APs.
>> +    - Maintain MP-related processor status.
>> +
>> +  The MP Services Protocol must be produced on any system with more 
>> than one logical
>> +  processor.
>> +
>> +  The Protocol is available only during boot time.
>> +
>> +  MP Services Protocol is hardware-independent. Most of the logic of 
>> this protocol
>> +  is architecturally neutral. It abstracts the multi-processor 
>> environment and
>> +  status of processors, and provides interfaces to retrieve 
>> information, maintain,
>> +  and dispatch.
>> +
>> +  MP Services Protocol may be consumed by ACPI module. The ACPI 
>> module may use this
>> +  protocol to retrieve data that are needed for an MP platform and 
>> report them to OS.
>> +  MP Services Protocol may also be used to program and configure 
>> processors, such
>> +  as MTRR synchronization for memory space attributes setting in DXE 
>> Services.
>> +  MP Services Protocol may be used by non-CPU DXE drivers to speed 
>> up platform boot
>> +  by taking advantage of the processing capabilities of the APs, for 
>> example, using
>> +  APs to help test system memory in parallel with other device 
>> initialization.
>> +  Diagnostics applications may also use this protocol for 
>> multi-processor.
>> +
>> +  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights 
>> reserved.<BR>
>> +  SPDX-License-Identifier: BSD-2-Clause-Patent
>> +
>> +**/
>> +
>> +#include <PiDxe.h>
>> +
>> +#include <Library/ArmLib.h>
>> +#include <Library/ArmMmuLib.h>
>> +#include <Library/ArmPlatformLib.h>
>> +#include <Library/ArmSmcLib.h>
>> +#include <Library/BaseMemoryLib.h>
>> +#include <Library/CacheMaintenanceLib.h>
>> +#include <Library/DebugLib.h>
>> +#include <Library/HobLib.h>
>> +#include <Library/MemoryAllocationLib.h>
>> +#include <Library/UefiBootServicesTableLib.h>
>> +#include <Library/UefiLib.h>
>> +
>> +#include <IndustryStandard/ArmStdSmc.h>
>> +#include <Ppi/ArmMpCoreInfo.h>
>> +#include <Protocol/LoadedImage.h>
>> +
>> +#include "MpServicesInternal.h"
>> +
>> +#define POLL_INTERVAL_US  50000
>> +
>> +#define GET_MPIDR_AFFINITY_BITS(x)  ((x) & 0xFF00FFFFFF)
>> +
>> +#define MPIDR_MT_BIT  BIT24
> [KQ]: Is there any reason why this is not defined in a more formal 
> place? I think that will allow the platform to use as well.
>> +
>> +STATIC CPU_MP_DATA  mCpuMpData;
>> +STATIC BOOLEAN      mNonBlockingModeAllowed;
>> +UINT64              *gApStacksBase;
>> +UINT64              *gProcessorIDs;
>> +CONST UINT64        gApStackSize = AP_STACK_SIZE;
>> +
>> +STATIC
>> +BOOLEAN
>> +IsCurrentProcessorBSP (
>> +  VOID
>> +  );
>> +
>> +/** Turns on the specified core using PSCI and executes the 
>> user-supplied
>> +    function that's been configured via a previous call to 
>> SetApProcedure.
>> +
>> +    @param ProcessorIndex The index of the core to turn on.
>> +
>> +    @retval EFI_SUCCESS      Success.
>> +    @retval EFI_DEVICE_ERROR The processor could not be turned on.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +DispatchCpu (
>> +  IN UINTN  ProcessorIndex
>> +  )
>> +{
>> +  ARM_SMC_ARGS  Args;
>> +  EFI_STATUS    Status;
>> +
>> +  Status = EFI_SUCCESS;
>> +
>> +  mCpuMpData.CpuData[ProcessorIndex].State = CpuStateBusy;
>> +
>> +  /* Turn the AP on */
>> +  if (sizeof (Args.Arg0) == sizeof (UINT32)) {
>> +    Args.Arg0 = ARM_SMC_ID_PSCI_CPU_ON_AARCH32;
>> +  } else {
>> +    Args.Arg0 = ARM_SMC_ID_PSCI_CPU_ON_AARCH64;
>> +  }
>> +
>> +  Args.Arg1 = gProcessorIDs[ProcessorIndex];
>> +  Args.Arg2 = (UINTN)ApEntryPoint;
>> +
>> +  mCpuMpData.CpuData[ProcessorIndex].Tcr   = ArmGetTCR ();
>> +  mCpuMpData.CpuData[ProcessorIndex].Mair  = ArmGetMAIR ();
>> +  mCpuMpData.CpuData[ProcessorIndex].Ttbr0 = ArmGetTTBR0BaseAddress ();
>> +  WriteBackDataCacheRange (&mCpuMpData.CpuData[ProcessorIndex], 
>> sizeof (CPU_AP_DATA));
>> +
>> +  ArmCallSmc (&Args);
>> +
>> +  if (Args.Arg0 != ARM_SMC_PSCI_RET_SUCCESS) {
>> +    DEBUG ((DEBUG_ERROR, "PSCI_CPU_ON call failed: %d\n", Args.Arg0));
>> +    Status = EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  return Status;
>> +}
>> +
>> +/** Returns whether the specified processor is the BSP.
>> +
>> +  @param[in] ProcessorIndex The index the processor to check.
>> +
>> +  @return TRUE if the processor is the BSP, FALSE otherwise.
>> +**/
>> +STATIC
>> +BOOLEAN
>> +IsProcessorBSP (
>> +  UINTN  ProcessorIndex
>> +  )
>> +{
>> +  EFI_PROCESSOR_INFORMATION  *CpuInfo;
>> +
>> +  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
>> +
>> +  return (CpuInfo->StatusFlag & PROCESSOR_AS_BSP_BIT) != 0;
>> +}
>> +
>> +/** Get the Application Processors state.
>> +
>> +  @param[in]  CpuData    The pointer to CPU_AP_DATA of specified AP.
>> +
>> +  @return The AP status.
>> +**/
>> +CPU_STATE
>> +GetApState (
>> +  IN  CPU_AP_DATA  *CpuData
>> +  )
>> +{
>> +  return CpuData->State;
>> +}
>> +
>> +/** Configures the processor context with the user-supplied 
>> procedure and
>> +    argument.
>> +
>> +   @param CpuData           The processor context.
>> +   @param Procedure         The user-supplied procedure.
>> +   @param ProcedureArgument The user-supplied procedure argument.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +SetApProcedure (
>> +  IN   CPU_AP_DATA       *CpuData,
>> +  IN   EFI_AP_PROCEDURE  Procedure,
>> +  IN   VOID              *ProcedureArgument
>> +  )
>> +{
>> +  ASSERT (CpuData != NULL);
>> +  ASSERT (Procedure != NULL);
>> +
>> +  CpuData->Parameter = ProcedureArgument;
>> +  CpuData->Procedure = Procedure;
>> +}
>> +
>> +/** Returns the index of the next processor that is blocked.
>> +
>> +   @param[out] NextNumber The index of the next blocked processor.
>> +
>> +   @retval EFI_SUCCESS   Successfully found the next blocked processor.
>> +   @retval EFI_NOT_FOUND There are no blocked processors.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +GetNextBlockedNumber (
>> +  OUT UINTN  *NextNumber
>> +  )
>> +{
>> +  UINTN        Index;
>> +  CPU_STATE    State;
>> +  CPU_AP_DATA  *CpuData;
>> +
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    CpuData = &mCpuMpData.CpuData[Index];
>> +    if (IsProcessorBSP (Index)) {
>> +      // Skip BSP
>> +      continue;
>> +    }
>> +
>> +    State = CpuData->State;
>> +
>> +    if (State == CpuStateBlocked) {
>> +      *NextNumber = Index;
>> +      return EFI_SUCCESS;
>> +    }
>> +  }
>> +
>> +  return EFI_NOT_FOUND;
>> +}
>> +
>> +/** Stalls the BSP for the minimum of POLL_INTERVAL_US and Timeout.
>> +
>> +   @param[in]  Timeout    The time limit in microseconds remaining for
>> +                          APs to return from Procedure.
>> +
>> +   @retval     StallTime  Time of execution stall.
>> +**/
>> +STATIC
>> +UINTN
>> +CalculateAndStallInterval (
>> +  IN UINTN  Timeout
>> +  )
>> +{
>> +  UINTN  StallTime;
>> +
>> +  if ((Timeout < POLL_INTERVAL_US) && (Timeout != 0)) {
>> +    StallTime = Timeout;
>> +  } else {
>> +    StallTime = POLL_INTERVAL_US;
>> +  }
>> +
>> +  gBS->Stall (StallTime);
>> +
>> +  return StallTime;
>> +}
>> +
>> +/**
>> +  This service retrieves the number of logical processor in the 
>> platform
>> +  and the number of those logical processors that are enabled on 
>> this boot.
>> +  This service may only be called from the BSP.
>> +
>> +  This function is used to retrieve the following information:
>> +    - The number of logical processors that are present in the system.
>> +    - The number of enabled logical processors in the system at the 
>> instant
>> +      this call is made.
>> +
>> +  Because MP Service Protocol provides services to enable and 
>> disable processors
>> +  dynamically, the number of enabled logical processors may vary 
>> during the
>> +  course of a boot session.
>> +
>> +  If this service is called from an AP, then EFI_DEVICE_ERROR is 
>> returned.
>> +  If NumberOfProcessors or NumberOfEnabledProcessors is NULL, then
>> +  EFI_INVALID_PARAMETER is returned. Otherwise, the total number of 
>> processors
>> +  is returned in NumberOfProcessors, the number of currently enabled 
>> processor
>> +  is returned in NumberOfEnabledProcessors, and EFI_SUCCESS is 
>> returned.
>> +
>> +  @param[in]  This                        A pointer to the
>> + EFI_MP_SERVICES_PROTOCOL instance.
>> +  @param[out] NumberOfProcessors          Pointer to the total 
>> number of logical
>> +                                          processors in the system, 
>> including
>> +                                          the BSP and disabled APs.
>> +  @param[out] NumberOfEnabledProcessors   Pointer to the number of 
>> enabled
>> +                                          logical processors that 
>> exist in the
>> +                                          system, including the BSP.
>> +
>> +  @retval EFI_SUCCESS             The number of logical processors 
>> and enabled
>> +                                  logical processors was retrieved.
>> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
>> +  @retval EFI_INVALID_PARAMETER   NumberOfProcessors is NULL.
>> +  @retval EFI_INVALID_PARAMETER   NumberOfEnabledProcessors is NULL.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +GetNumberOfProcessors (
>> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
>> +  OUT UINTN                     *NumberOfProcessors,
>> +  OUT UINTN                     *NumberOfEnabledProcessors
>> +  )
>> +{
>> +  if ((NumberOfProcessors == NULL) || (NumberOfEnabledProcessors == 
>> NULL)) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (!IsCurrentProcessorBSP ()) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  *NumberOfProcessors        = mCpuMpData.NumberOfProcessors;
>> +  *NumberOfEnabledProcessors = mCpuMpData.NumberOfEnabledProcessors;
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +/**
>> +  Gets detailed MP-related information on the requested processor at 
>> the
>> +  instant this call is made. This service may only be called from 
>> the BSP.
>> +
>> +  This service retrieves detailed MP-related information about any 
>> processor
>> +  on the platform. Note the following:
>> +    - The processor information may change during the course of a 
>> boot session.
>> +    - The information presented here is entirely MP related.
>> +
>> +  Information regarding the number of caches and their sizes, 
>> frequency of
>> +  operation, slot numbers is all considered platform-related 
>> information and is
>> +  not provided by this service.
>> +
>> +  @param[in]  This                  A pointer to the 
>> EFI_MP_SERVICES_PROTOCOL
>> +                                    instance.
>> +  @param[in]  ProcessorIndex        The index of the processor.
>> +  @param[out] ProcessorInfoBuffer   A pointer to the buffer where 
>> information
>> +                                    for the requested processor is 
>> deposited.
>> +
>> +  @retval EFI_SUCCESS             Processor information was returned.
>> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
>> +  @retval EFI_INVALID_PARAMETER   ProcessorInfoBuffer is NULL.
>> +  @retval EFI_NOT_FOUND           The processor with the handle 
>> specified by
>> +                                  ProcessorNumber does not exist in 
>> the platform.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +GetProcessorInfo (
>> +  IN  EFI_MP_SERVICES_PROTOCOL   *This,
>> +  IN  UINTN                      ProcessorIndex,
>> +  OUT EFI_PROCESSOR_INFORMATION  *ProcessorInfoBuffer
>> +  )
>> +{
>> +  if (ProcessorInfoBuffer == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (!IsCurrentProcessorBSP ()) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  ProcessorIndex &= ~CPU_V2_EXTENDED_TOPOLOGY;
>> +
>> +  if (ProcessorIndex >= mCpuMpData.NumberOfProcessors) {
>> +    return EFI_NOT_FOUND;
>> +  }
>> +
>> +  CopyMem (
>> +    ProcessorInfoBuffer,
>> +    &mCpuMpData.CpuData[ProcessorIndex],
>> +    sizeof (EFI_PROCESSOR_INFORMATION)
>> +    );
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +/**
>> +  This service executes a caller provided function on all enabled 
>> APs. APs can
>> +  run either simultaneously or one at a time in sequence. This 
>> service supports
>> +  both blocking and non-blocking requests. The non-blocking requests 
>> use EFI
>> +  events so the BSP can detect when the APs have finished. This 
>> service may only
>> +  be called from the BSP.
>> +
>> +  This function is used to dispatch all the enabled APs to the function
>> +  specified by Procedure.  If any enabled AP is busy, then 
>> EFI_NOT_READY is
>> +  returned immediately and Procedure is not started on any AP.
>> +
>> +  If SingleThread is TRUE, all the enabled APs execute the function 
>> specified by
>> +  Procedure one by one, in ascending order of processor handle number.
>> +  Otherwise, all the enabled APs execute the function specified by 
>> Procedure
>> +  simultaneously.
>> +
>> +  If WaitEvent is NULL, execution is in blocking mode. The BSP waits 
>> until all
>> +  APs finish or TimeoutInMicroseconds expires. Otherwise, execution 
>> is in
>> +  non-blocking mode, and the BSP returns from this service without 
>> waiting for
>> +  APs. If a non-blocking mode is requested after the UEFI Event
>> +  EFI_EVENT_GROUP_READY_TO_BOOT is signaled, then EFI_UNSUPPORTED 
>> must be
>> +  returned.
>> +
>> +  If the timeout specified by TimeoutInMicroseconds expires before 
>> all APs
>> +  return from Procedure, then Procedure on the failed APs is 
>> terminated.
>> +  All enabled APs are always available for further calls to
>> +  EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and
>> +  EFI_MP_SERVICES_PROTOCOL.StartupThisAP(). If FailedCpuList is not 
>> NULL, its
>> +  content points to the list of processor handle numbers in which 
>> Procedure was
>> +  terminated.
>> +
>> +  Note: It is the responsibility of the consumer of the
>> +  EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() to make sure that the 
>> nature of the
>> +  code that is executed on the BSP and the dispatched APs is well 
>> controlled.
>> +  The MP Services Protocol does not guarantee that the Procedure 
>> function is
>> +  MP-safe. Hence, the tasks that can be run in parallel are limited 
>> to certain
>> +  independent tasks and well-controlled exclusive code. EFI services 
>> and
>> +  protocols may not be called by APs unless otherwise specified.
>> +
>> +  In blocking execution mode, BSP waits until all APs finish or
>> +  TimeoutInMicroseconds expires.
>> +
>> +  In non-blocking execution mode, BSP is freed to return to the 
>> caller and then
>> +  proceed to the next task without having to wait for APs. The 
>> following
>> +  sequence needs to occur in a non-blocking execution mode:
>> +
>> +    -# The caller that intends to use this MP Services Protocol in 
>> non-blocking
>> +       mode creates WaitEvent by calling the EFI CreateEvent() 
>> service.  The
>> +       caller invokes EFI_MP_SERVICES_PROTOCOL.StartupAllAPs(). If 
>> the parameter
>> +       WaitEvent is not NULL, then StartupAllAPs() executes in 
>> non-blocking
>> +       mode. It requests the function specified by Procedure to be 
>> started on
>> +       all the enabled APs, and releases the BSP to continue with 
>> other tasks.
>> +    -# The caller can use the CheckEvent() and WaitForEvent() 
>> services to check
>> +       the state of the WaitEvent created in step 1.
>> +    -# When the APs complete their task or TimeoutInMicroSecondss 
>> expires, the
>> +       MP Service signals WaitEvent by calling the EFI SignalEvent() 
>> function.
>> +       If FailedCpuList is not NULL, its content is available when 
>> WaitEvent is
>> +       signaled. If all APs returned from Procedure prior to the 
>> timeout, then
>> +       FailedCpuList is set to NULL. If not all APs return from 
>> Procedure before
>> +       the timeout, then FailedCpuList is filled in with the list of 
>> the failed
>> +       APs. The buffer is allocated by MP Service Protocol using 
>> AllocatePool().
>> +       It is the caller's responsibility to free the buffer with 
>> FreePool()
>> +       service.
>> +    -# This invocation of SignalEvent() function informs the caller 
>> that invoked
>> +       EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() that either all the APs
>> +       completed the specified task or a timeout occurred. The 
>> contents of
>> +       FailedCpuList can be examined to determine which APs did not 
>> complete the
>> +       specified task prior to the timeout.
>> +
>> +  @param[in]  This                    A pointer to the 
>> EFI_MP_SERVICES_PROTOCOL
>> +                                      instance.
>> +  @param[in]  Procedure               A pointer to the function to 
>> be run on
>> +                                      enabled APs of the system. See 
>> type
>> +                                      EFI_AP_PROCEDURE.
>> +  @param[in]  SingleThread            If TRUE, then all the enabled 
>> APs execute
>> +                                      the function specified by 
>> Procedure one by
>> +                                      one, in ascending order of 
>> processor
>> +                                      handle number.  If FALSE, then 
>> all the
>> +                                      enabled APs execute the 
>> function specified
>> +                                      by Procedure simultaneously.
>> +  @param[in]  WaitEvent               The event created by the 
>> caller with
>> +                                      CreateEvent() service. If it 
>> is NULL,
>> +                                      then execute in blocking mode. 
>> BSP waits
>> +                                      until all APs finish or
>> +                                      TimeoutInMicroseconds 
>> expires.  If it's
>> +                                      not NULL, then execute in 
>> non-blocking
>> +                                      mode. BSP requests the 
>> function specified
>> +                                      by Procedure to be started on 
>> all the
>> +                                      enabled APs, and go on executing
>> +                                      immediately. If all return 
>> from Procedure,
>> +                                      or TimeoutInMicroseconds 
>> expires, this
>> +                                      event is signaled. The BSP can 
>> use the
>> +                                      CheckEvent() or WaitForEvent()
>> +                                      services to check the state of 
>> event. Type
>> +                                      EFI_EVENT is defined in 
>> CreateEvent() in
>> +                                      the Unified Extensible 
>> Firmware Interface
>> +                                      Specification.
>> +  @param[in]  TimeoutInMicroseconds   Indicates the time limit in 
>> microseconds
>> +                                      for APs to return from 
>> Procedure, either
>> +                                      for blocking or non-blocking 
>> mode. Zero
>> +                                      means infinity.  If the 
>> timeout expires
>> +                                      before all APs return from 
>> Procedure, then
>> +                                      Procedure on the failed APs is 
>> terminated.
>> +                                      All enabled APs are available 
>> for next
>> +                                      function assigned by
>> + EFI_MP_SERVICES_PROTOCOL.StartupAllAPs()
>> +                                      or 
>> EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
>> +                                      If the timeout expires in 
>> blocking mode,
>> +                                      BSP returns EFI_TIMEOUT. If 
>> the timeout
>> +                                      expires in non-blocking mode, 
>> WaitEvent
>> +                                      is signaled with SignalEvent().
>> +  @param[in]  ProcedureArgument       The parameter passed into 
>> Procedure for
>> +                                      all APs.
>> +  @param[out] FailedCpuList           If NULL, this parameter is 
>> ignored.
>> +                                      Otherwise, if all APs finish 
>> successfully,
>> +                                      then its content is set to 
>> NULL. If not
>> +                                      all APs finish before timeout 
>> expires,
>> +                                      then its content is set to 
>> address of the
>> +                                      buffer holding handle numbers 
>> of the
>> +                                      failed APs.
>> +                                      The buffer is allocated by MP 
>> Service
>> +                                      Protocol, and it's the caller's
>> +                                      responsibility to free the 
>> buffer with
>> +                                      FreePool() service.
>> +                                      In blocking mode, it is ready for
>> +                                      consumption when the call 
>> returns. In
>> +                                      non-blocking mode, it is ready 
>> when
>> +                                      WaitEvent is signaled. The 
>> list of failed
>> +                                      CPU is terminated by 
>> END_OF_CPU_LIST.
>> +
>> +  @retval EFI_SUCCESS             In blocking mode, all APs have 
>> finished before
>> +                                  the timeout expired.
>> +  @retval EFI_SUCCESS             In non-blocking mode, function has 
>> been
>> +                                  dispatched to all enabled APs.
>> +  @retval EFI_UNSUPPORTED         A non-blocking mode request was 
>> made after the
>> +                                  UEFI event 
>> EFI_EVENT_GROUP_READY_TO_BOOT was
>> +                                  signaled.
>> +  @retval EFI_DEVICE_ERROR        Caller processor is AP.
>> +  @retval EFI_NOT_STARTED         No enabled APs exist in the system.
>> +  @retval EFI_NOT_READY           Any enabled APs are busy.
>> +  @retval EFI_TIMEOUT             In blocking mode, the timeout 
>> expired before
>> +                                  all enabled APs have finished.
>> +  @retval EFI_INVALID_PARAMETER   Procedure is NULL.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +StartupAllAPs (
>> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
>> +  IN  EFI_AP_PROCEDURE          Procedure,
>> +  IN  BOOLEAN                   SingleThread,
>> +  IN  EFI_EVENT                 WaitEvent OPTIONAL,
>> +  IN  UINTN                     TimeoutInMicroseconds,
>> +  IN  VOID                      *ProcedureArgument OPTIONAL,
>> +  OUT UINTN                     **FailedCpuList OPTIONAL
>> +  )
>> +{
>> +  EFI_STATUS  Status;
>> +
>> +  if (!IsCurrentProcessorBSP ()) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  if (mCpuMpData.NumberOfProcessors == 1) {
>> +    return EFI_NOT_STARTED;
>> +  }
>> +
>> +  if (Procedure == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if ((WaitEvent != NULL) && !mNonBlockingModeAllowed) {
>> +    return EFI_UNSUPPORTED;
>> +  }
>> +
>> +  if (!CheckAllCpusReady ()) {
>> +    return EFI_NOT_READY;
>> +  }
>> +
>> +  if (FailedCpuList != NULL) {
>> +    mCpuMpData.FailedList = AllocatePool (
>> +                              (mCpuMpData.NumberOfProcessors + 1) *
>> +                              sizeof (UINTN)
>> +                              );
>> +    if (mCpuMpData.FailedList == NULL) {
>> +      return EFI_OUT_OF_RESOURCES;
>> +    }
>> +
>> +    SetMemN (
>> +      mCpuMpData.FailedList,
>> +      (mCpuMpData.NumberOfProcessors + 1) *
>> +      sizeof (UINTN),
>> +      END_OF_CPU_LIST
>> +      );
>> +    mCpuMpData.FailedListIndex = 0;
>> +    *FailedCpuList             = mCpuMpData.FailedList;
>> +  }
>> +
>> +  StartupAllAPsPrepareState (SingleThread);
>> +
>> +  if (WaitEvent != NULL) {
>> +    Status = StartupAllAPsWithWaitEvent (
>> +               Procedure,
>> +               ProcedureArgument,
>> +               WaitEvent,
>> +               TimeoutInMicroseconds
>> +               );
>> +  } else {
>> +    Status = StartupAllAPsNoWaitEvent (
>> +               Procedure,
>> +               ProcedureArgument,
>> +               TimeoutInMicroseconds,
>> +               SingleThread,
>> +               FailedCpuList
>> +               );
>> +  }
>> +
>> +  return Status;
>> +}
>> +
>> +/**
>> +  This service lets the caller get one enabled AP to execute a 
>> caller-provided
>> +  function. The caller can request the BSP to either wait for the 
>> completion
>> +  of the AP or just proceed with the next task by using the EFI 
>> event mechanism.
>> +  See EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() for more details on 
>> non-blocking
>> +  execution support.  This service may only be called from the BSP.
>> +
>> +  This function is used to dispatch one enabled AP to the function 
>> specified by
>> +  Procedure passing in the argument specified by ProcedureArgument.  
>> If WaitEvent
>> +  is NULL, execution is in blocking mode. The BSP waits until the AP 
>> finishes or
>> +  TimeoutInMicroSecondss expires. Otherwise, execution is in 
>> non-blocking mode.
>> +  BSP proceeds to the next task without waiting for the AP. If a 
>> non-blocking mode
>> +  is requested after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is 
>> signaled,
>> +  then EFI_UNSUPPORTED must be returned.
>> +
>> +  If the timeout specified by TimeoutInMicroseconds expires before 
>> the AP returns
>> +  from Procedure, then execution of Procedure by the AP is 
>> terminated. The AP is
>> +  available for subsequent calls to 
>> EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and
>> +  EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
>> +
>> +  @param[in]  This                    A pointer to the 
>> EFI_MP_SERVICES_PROTOCOL
>> +                                      instance.
>> +  @param[in]  Procedure               A pointer to the function to 
>> be run on
>> +                                      enabled APs of the system. See 
>> type
>> +                                      EFI_AP_PROCEDURE.
>> +  @param[in]  ProcessorNumber         The handle number of the AP. 
>> The range is
>> +                                      from 0 to the total number of 
>> logical
>> +                                      processors minus 1. The total 
>> number of
>> +                                      logical processors can be 
>> retrieved by
>> + EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
>> +  @param[in]  WaitEvent               The event created by the 
>> caller with CreateEvent()
>> +                                      service.  If it is NULL, then 
>> execute in
>> +                                      blocking mode. BSP waits until 
>> all APs finish
>> +                                      or TimeoutInMicroseconds 
>> expires.  If it's
>> +                                      not NULL, then execute in 
>> non-blocking mode.
>> +                                      BSP requests the function 
>> specified by
>> +                                      Procedure to be started on all 
>> the enabled
>> +                                      APs, and go on executing 
>> immediately. If
>> +                                      all return from Procedure or 
>> TimeoutInMicroseconds
>> +                                      expires, this event is 
>> signaled. The BSP
>> +                                      can use the CheckEvent() or 
>> WaitForEvent()
>> +                                      services to check the state of 
>> event.  Type
>> +                                      EFI_EVENT is defined in 
>> CreateEvent() in
>> +                                      the Unified Extensible 
>> Firmware Interface
>> +                                      Specification.
>> +  @param[in]  TimeoutInMicroseconds   Indicates the time limit in 
>> microseconds for
>> +                                      APs to return from Procedure, 
>> either for
>> +                                      blocking or non-blocking mode. 
>> Zero means
>> +                                      infinity.  If the timeout 
>> expires before
>> +                                      all APs return from Procedure, 
>> then Procedure
>> +                                      on the failed APs is 
>> terminated. All enabled
>> +                                      APs are available for next 
>> function assigned
>> +                                      by 
>> EFI_MP_SERVICES_PROTOCOL.StartupAllAPs()
>> +                                      or 
>> EFI_MP_SERVICES_PROTOCOL.StartupThisAP().
>> +                                      If the timeout expires in 
>> blocking mode,
>> +                                      BSP returns EFI_TIMEOUT. If 
>> the timeout
>> +                                      expires in non-blocking mode, 
>> WaitEvent
>> +                                      is signaled with SignalEvent().
>> +  @param[in]  ProcedureArgument       The parameter passed into 
>> Procedure for
>> +                                      all APs.
>> +  @param[out] Finished                If NULL, this parameter is 
>> ignored.  In
>> +                                      blocking mode, this parameter 
>> is ignored.
>> +                                      In non-blocking mode, if AP 
>> returns from
>> +                                      Procedure before the timeout 
>> expires, its
>> +                                      content is set to TRUE. 
>> Otherwise, the
>> +                                      value is set to FALSE. The 
>> caller can
>> +                                      determine if the AP returned 
>> from Procedure
>> +                                      by evaluating this value.
>> +
>> +  @retval EFI_SUCCESS             In blocking mode, specified AP 
>> finished before
>> +                                  the timeout expires.
>> +  @retval EFI_SUCCESS             In non-blocking mode, the function 
>> has been
>> +                                  dispatched to specified AP.
>> +  @retval EFI_UNSUPPORTED         A non-blocking mode request was 
>> made after the
>> +                                  UEFI event 
>> EFI_EVENT_GROUP_READY_TO_BOOT was
>> +                                  signaled.
>> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
>> +  @retval EFI_TIMEOUT             In blocking mode, the timeout 
>> expired before
>> +                                  the specified AP has finished.
>> +  @retval EFI_NOT_READY           The specified AP is busy.
>> +  @retval EFI_NOT_FOUND           The processor with the handle 
>> specified by
>> +                                  ProcessorNumber does not exist.
>> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP 
>> or disabled AP.
>> +  @retval EFI_INVALID_PARAMETER   Procedure is NULL.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +StartupThisAP (
>> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
>> +  IN  EFI_AP_PROCEDURE          Procedure,
>> +  IN  UINTN                     ProcessorNumber,
>> +  IN  EFI_EVENT                 WaitEvent OPTIONAL,
>> +  IN  UINTN                     TimeoutInMicroseconds,
>> +  IN  VOID                      *ProcedureArgument OPTIONAL,
>> +  OUT BOOLEAN                   *Finished OPTIONAL
>> +  )
>> +{
>> +  EFI_STATUS   Status;
>> +  UINTN        Timeout;
>> +  CPU_AP_DATA  *CpuData;
>> +
>> +  if (!IsCurrentProcessorBSP ()) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  if (Procedure == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (ProcessorNumber >= mCpuMpData.NumberOfProcessors) {
>> +    return EFI_NOT_FOUND;
>> +  }
>> +
>> +  CpuData = &mCpuMpData.CpuData[ProcessorNumber];
>> +
>> +  if (IsProcessorBSP (ProcessorNumber)) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (!IsProcessorEnabled (ProcessorNumber)) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (GetApState (CpuData) != CpuStateIdle) {
>> +    return EFI_NOT_READY;
>> +  }
>> +
>> +  if ((WaitEvent != NULL) && !mNonBlockingModeAllowed) {
>> +    return EFI_UNSUPPORTED;
>> +  }
>> +
>> +  Timeout = TimeoutInMicroseconds;
>> +
>> +  mCpuMpData.StartCount  = 1;
>> +  mCpuMpData.FinishCount = 0;
>> +
>> +  SetApProcedure (
>> +    CpuData,
>> +    Procedure,
>> +    ProcedureArgument
>> +    );
>> +
>> +  Status = DispatchCpu (ProcessorNumber);
>> +  if (EFI_ERROR (Status)) {
>> +    CpuData->State = CpuStateIdle;
>> +    return EFI_NOT_READY;
>> +  }
>> +
>> +  if (WaitEvent != NULL) {
>> +    // Non Blocking
>> +    mCpuMpData.WaitEvent = WaitEvent;
>> +    gBS->SetTimer (
>> +           CpuData->CheckThisAPEvent,
>> +           TimerPeriodic,
>> +           POLL_INTERVAL_US
>> +           );
>> +    return EFI_SUCCESS;
>> +  }
>> +
>> +  // Blocking
>> +  while (TRUE) {
>> +    if (GetApState (CpuData) == CpuStateFinished) {
>> +      CpuData->State = CpuStateIdle;
>> +      break;
>> +    }
>> +
>> +    if ((TimeoutInMicroseconds != 0) && (Timeout == 0)) {
>> +      return EFI_TIMEOUT;
>> +    }
>> +
>> +    Timeout -= CalculateAndStallInterval (Timeout);
>> +  }
>> +
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +/**
>> +  This service switches the requested AP to be the BSP from that 
>> point onward.
>> +  This service changes the BSP for all purposes.   This call can 
>> only be
>> +  performed by the current BSP.
>> +
>> +  This service switches the requested AP to be the BSP from that 
>> point onward.
>> +  This service changes the BSP for all purposes. The new BSP can 
>> take over the
>> +  execution of the old BSP and continue seamlessly from where the 
>> old one left
>> +  off. This service may not be supported after the UEFI Event 
>> EFI_EVENT_GROUP_READY_TO_BOOT
>> +  is signaled.
>> +
>> +  If the BSP cannot be switched prior to the return from this 
>> service, then
>> +  EFI_UNSUPPORTED must be returned.
>> +
>> +  @param[in] This              A pointer to the 
>> EFI_MP_SERVICES_PROTOCOL instance.
>> +  @param[in] ProcessorNumber   The handle number of AP that is to 
>> become the new
>> +                               BSP. The range is from 0 to the total 
>> number of
>> +                               logical processors minus 1. The total 
>> number of
>> +                               logical processors can be retrieved by
>> + EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
>> +  @param[in] EnableOldBSP      If TRUE, then the old BSP will be 
>> listed as an
>> +                               enabled AP. Otherwise, it will be 
>> disabled.
>> +
>> +  @retval EFI_SUCCESS             BSP successfully switched.
>> +  @retval EFI_UNSUPPORTED         Switching the BSP cannot be 
>> completed prior to
>> +                                  this service returning.
>> +  @retval EFI_UNSUPPORTED         Switching the BSP is not supported.
>> +  @retval EFI_SUCCESS             The calling processor is an AP.
>> +  @retval EFI_NOT_FOUND           The processor with the handle 
>> specified by
>> +                                  ProcessorNumber does not exist.
>> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the 
>> current BSP or
>> +                                  a disabled AP.
>> +  @retval EFI_NOT_READY           The specified AP is busy.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +SwitchBSP (
>> +  IN EFI_MP_SERVICES_PROTOCOL  *This,
>> +  IN  UINTN                    ProcessorNumber,
>> +  IN  BOOLEAN                  EnableOldBSP
>> +  )
>> +{
>> +  return EFI_UNSUPPORTED;
>> +}
>> +
>> +/**
>> +  This service lets the caller enable or disable an AP from this 
>> point onward.
>> +  This service may only be called from the BSP.
>> +
>> +  This service allows the caller enable or disable an AP from this 
>> point onward.
>> +  The caller can optionally specify the health status of the AP by 
>> Health. If
>> +  an AP is being disabled, then the state of the disabled AP is 
>> implementation
>> +  dependent. If an AP is enabled, then the implementation must 
>> guarantee that a
>> +  complete initialization sequence is performed on the AP, so the AP 
>> is in a state
>> +  that is compatible with an MP operating system. This service may 
>> not be supported
>> +  after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled.
>> +
>> +  If the enable or disable AP operation cannot be completed prior to 
>> the return
>> +  from this service, then EFI_UNSUPPORTED must be returned.
>> +
>> +  @param[in] This              A pointer to the 
>> EFI_MP_SERVICES_PROTOCOL instance.
>> +  @param[in] ProcessorNumber   The handle number of AP that is to 
>> become the new
>> +                               BSP. The range is from 0 to the total 
>> number of
>> +                               logical processors minus 1. The total 
>> number of
>> +                               logical processors can be retrieved by
>> + EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
>> +  @param[in] EnableAP          Specifies the new state for the 
>> processor for
>> +                               enabled, FALSE for disabled.
>> +  @param[in] HealthFlag        If not NULL, a pointer to a value 
>> that specifies
>> +                               the new health status of the AP. This 
>> flag
>> +                               corresponds to StatusFlag defined in
>> + EFI_MP_SERVICES_PROTOCOL.GetProcessorInfo(). Only
>> +                               the PROCESSOR_HEALTH_STATUS_BIT is 
>> used. All other
>> +                               bits are ignored.  If it is NULL, 
>> this parameter
>> +                               is ignored.
>> +
>> +  @retval EFI_SUCCESS             The specified AP was enabled or 
>> disabled successfully.
>> +  @retval EFI_UNSUPPORTED         Enabling or disabling an AP cannot 
>> be completed
>> +                                  prior to this service returning.
>> +  @retval EFI_UNSUPPORTED         Enabling or disabling an AP is not 
>> supported.
>> +  @retval EFI_DEVICE_ERROR        The calling processor is an AP.
>> +  @retval EFI_NOT_FOUND           Processor with the handle 
>> specified by ProcessorNumber
>> +                                  does not exist.
>> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +EnableDisableAP (
>> +  IN  EFI_MP_SERVICES_PROTOCOL  *This,
>> +  IN  UINTN                     ProcessorNumber,
>> +  IN  BOOLEAN                   EnableAP,
>> +  IN  UINT32                    *HealthFlag OPTIONAL
>> +  )
>> +{
>> +  UINTN        StatusFlag;
>> +  CPU_AP_DATA  *CpuData;
>> +
>> +  StatusFlag = mCpuMpData.CpuData[ProcessorNumber].Info.StatusFlag;
>> +  CpuData    = &mCpuMpData.CpuData[ProcessorNumber];
>> +
>> +  if (!IsCurrentProcessorBSP ()) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  if (ProcessorNumber >= mCpuMpData.NumberOfProcessors) {
>> +    return EFI_NOT_FOUND;
>> +  }
>> +
>> +  if (IsProcessorBSP (ProcessorNumber)) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (GetApState (CpuData) != CpuStateIdle) {
>> +    return EFI_UNSUPPORTED;
>> +  }
>> +
>> +  if (EnableAP) {
>> +    if (!IsProcessorEnabled (ProcessorNumber)) {
>> +      mCpuMpData.NumberOfEnabledProcessors++;
>> +    }
>> +
>> +    StatusFlag |= PROCESSOR_ENABLED_BIT;
>> +  } else {
>> +    if (IsProcessorEnabled (ProcessorNumber)) {
>> +      mCpuMpData.NumberOfEnabledProcessors--;
>> +    }
>> +
>> +    StatusFlag &= ~PROCESSOR_ENABLED_BIT;
>> +  }
>> +
>> +  if (HealthFlag != NULL) {
>> +    StatusFlag &= ~PROCESSOR_HEALTH_STATUS_BIT;
>> +    StatusFlag |= (*HealthFlag & PROCESSOR_HEALTH_STATUS_BIT);
>> +  }
>> +
>> +  mCpuMpData.CpuData[ProcessorNumber].Info.StatusFlag = StatusFlag;
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +/**
>> +  This return the handle number for the calling processor. This 
>> service may be
>> +  called from the BSP and APs.
>> +
>> +  This service returns the processor handle number for the calling 
>> processor.
>> +  The returned value is in the range from 0 to the total number of 
>> logical
>> +  processors minus 1. The total number of logical processors can be 
>> retrieved
>> +  with EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors(). This 
>> service may be
>> +  called from the BSP and APs. If ProcessorNumber is NULL, then 
>> EFI_INVALID_PARAMETER
>> +  is returned. Otherwise, the current processors handle number is 
>> returned in
>> +  ProcessorNumber, and EFI_SUCCESS is returned.
>> +
>> +  @param[in] This              A pointer to the 
>> EFI_MP_SERVICES_PROTOCOL instance.
>> +  @param[out] ProcessorNumber  The handle number of AP that is to 
>> become the new
>> +                               BSP. The range is from 0 to the total 
>> number of
>> +                               logical processors minus 1. The total 
>> number of
>> +                               logical processors can be retrieved by
>> + EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
>> +
>> +  @retval EFI_SUCCESS             The current processor handle 
>> number was returned
>> +                                  in ProcessorNumber.
>> +  @retval EFI_INVALID_PARAMETER   ProcessorNumber is NULL.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +WhoAmI (
>> +  IN EFI_MP_SERVICES_PROTOCOL  *This,
>> +  OUT UINTN                    *ProcessorNumber
>> +  )
>> +{
>> +  UINTN   Index;
>> +  UINT64  ProcessorId;
>> +
>> +  if (ProcessorNumber == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  ProcessorId = GET_MPIDR_AFFINITY_BITS (ArmReadMpidr ());
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    if (ProcessorId == gProcessorIDs[Index]) {
>> +      *ProcessorNumber = Index;
>> +      break;
>> +    }
>> +  }
>> +
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +STATIC EFI_MP_SERVICES_PROTOCOL  mMpServicesProtocol = {
>> +  GetNumberOfProcessors,
>> +  GetProcessorInfo,
>> +  StartupAllAPs,
>> +  StartupThisAP,
>> +  SwitchBSP,
>> +  EnableDisableAP,
>> +  WhoAmI
>> +};
>> +
>> +/** Adds the specified processor the list of failed processors.
>> +
>> +   @param ProcessorIndex The processor index to add.
>> +   @param ApState        Processor state.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +AddProcessorToFailedList (
>> +  UINTN      ProcessorIndex,
>> +  CPU_STATE  ApState
>> +  )
>> +{
>> +  UINTN    Index;
>> +  BOOLEAN  Found;
>> +
>> +  Found = FALSE;
>> +
>> +  if (ApState == CpuStateIdle) {
>> +    return;
>> +  }
>> +
>> +  // If we are retrying make sure we don't double count
>> +  for (Index = 0; Index < mCpuMpData.FailedListIndex; Index++) {
>> +    if (mCpuMpData.FailedList[Index] == ProcessorIndex) {
>> +      Found = TRUE;
>> +      break;
>> +    }
>> +  }
>> +
>> +  /* If the CPU isn't already in the FailedList, add it */
>> +  if (!Found) {
>> +    mCpuMpData.FailedList[mCpuMpData.FailedListIndex++] = Index;
>> +  }
>> +}
>> +
>> +/** Handles the StartupAllAPs case where the timeout has occurred.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +ProcessStartupAllAPsTimeout (
>> +  VOID
>> +  )
>> +{
>> +  CPU_AP_DATA  *CpuData;
>> +  UINTN        Index;
>> +
>> +  if (mCpuMpData.FailedList == NULL) {
>> +    return;
>> +  }
>> +
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    CpuData = &mCpuMpData.CpuData[Index];
>> +    if (IsProcessorBSP (Index)) {
>> +      // Skip BSP
>> +      continue;
>> +    }
>> +
>> +    if (!IsProcessorEnabled (Index)) {
>> +      // Skip Disabled processors
>> +      continue;
>> +    }
>> +
>> +    CpuData = &mCpuMpData.CpuData[Index];
>> +    AddProcessorToFailedList (Index, GetApState (CpuData));
>> +  }
>> +}
>> +
>> +/** Updates the status of the APs.
>> +
>> +   @param[in] ProcessorIndex The index of the AP to update.
>> +**/
>> +STATIC
>> +VOID
>> +UpdateApStatus (
>> +  IN UINTN  ProcessorIndex
>> +  )
>> +{
>> +  EFI_STATUS   Status;
>> +  CPU_AP_DATA  *CpuData;
>> +  CPU_AP_DATA  *NextCpuData;
>> +  CPU_STATE    State;
>> +  UINTN        NextNumber;
>> +
>> +  CpuData = &mCpuMpData.CpuData[ProcessorIndex];
>> +
>> +  if (IsProcessorBSP (ProcessorIndex)) {
>> +    // Skip BSP
>> +    return;
>> +  }
>> +
>> +  if (!IsProcessorEnabled (ProcessorIndex)) {
>> +    // Skip Disabled processors
>> +    return;
>> +  }
>> +
>> +  State = GetApState (CpuData);
>> +
>> +  switch (State) {
>> +    case CpuStateFinished:
>> +      if (mCpuMpData.SingleThread) {
>> +        Status = GetNextBlockedNumber (&NextNumber);
>> +        if (!EFI_ERROR (Status)) {
>> +          NextCpuData = &mCpuMpData.CpuData[NextNumber];
>> +
>> +          NextCpuData->State = CpuStateReady;
>> +
>> +          SetApProcedure (
>> +            NextCpuData,
>> +            mCpuMpData.Procedure,
>> +            mCpuMpData.ProcedureArgument
>> +            );
>> +        }
>> +      }
>> +
>> +      CpuData->State = CpuStateIdle;
>> +      mCpuMpData.FinishCount++;
>> +      break;
>> +
>> +    default:
>> +      break;
>> +  }
>> +}
>> +
>> +/**
>> +  If a timeout is specified in StartupAllAps(), a timer is set, 
>> which invokes
>> +  this procedure periodically to check whether all APs have finished.
>> +
>> +  @param[in] Event   The WaitEvent the user supplied.
>> +  @param[in] Context The event context.
>> +**/
>> +STATIC
>> +VOID
>> +EFIAPI
>> +CheckAllAPsStatus (
>> +  IN  EFI_EVENT  Event,
>> +  IN  VOID       *Context
>> +  )
>> +{
>> +  UINTN  Index;
>> +
>> +  if (mCpuMpData.TimeoutActive) {
>> +    mCpuMpData.Timeout -= CalculateAndStallInterval 
>> (mCpuMpData.Timeout);
>> +  }
>> +
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    UpdateApStatus (Index);
>> +  }
>> +
>> +  if (mCpuMpData.TimeoutActive && (mCpuMpData.Timeout == 0)) {
>> +    ProcessStartupAllAPsTimeout ();
>> +
>> +    // Force terminal exit
>> +    mCpuMpData.FinishCount = mCpuMpData.StartCount;
>> +  }
>> +
>> +  if (mCpuMpData.FinishCount != mCpuMpData.StartCount) {
>> +    return;
>> +  }
>> +
>> +  gBS->SetTimer (
>> +         mCpuMpData.CheckAllAPsEvent,
>> +         TimerCancel,
>> +         0
>> +         );
>> +
>> +  if (mCpuMpData.FailedListIndex == 0) {
>> +    if (mCpuMpData.FailedList != NULL) {
>> +      FreePool (mCpuMpData.FailedList);
>> +      mCpuMpData.FailedList = NULL;
>> +    }
>> +  }
>> +
>> +  gBS->SignalEvent (mCpuMpData.WaitEvent);
>> +}
>> +
>> +/** Invoked periodically via a timer to check the state of the 
>> processor.
>> +
>> +   @param Event   The event supplied by the timer expiration.
>> +   @param Context The processor context.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +EFIAPI
>> +CheckThisAPStatus (
>> +  IN  EFI_EVENT  Event,
>> +  IN  VOID       *Context
>> +  )
>> +{
>> +  EFI_STATUS   Status;
>> +  CPU_AP_DATA  *CpuData;
>> +  CPU_STATE    State;
>> +
>> +  CpuData             = Context;
>> +  CpuData->TimeTaken += POLL_INTERVAL_US;
>> +
>> +  State = GetApState (CpuData);
>> +
>> +  if (State == CpuStateFinished) {
>> +    Status = gBS->SetTimer (CpuData->CheckThisAPEvent, TimerCancel, 0);
>> +    ASSERT_EFI_ERROR (Status);
>> +
>> +    if (mCpuMpData.WaitEvent != NULL) {
>> +      Status = gBS->SignalEvent (mCpuMpData.WaitEvent);
>> +      ASSERT_EFI_ERROR (Status);
>> +    }
>> +
>> +    CpuData->State = CpuStateIdle;
>> +  }
>> +
>> +  if (CpuData->TimeTaken > CpuData->Timeout) {
>> +    if (mCpuMpData.WaitEvent != NULL) {
>> +      Status = gBS->SignalEvent (mCpuMpData.WaitEvent);
>> +      ASSERT_EFI_ERROR (Status);
>> +    }
>> +  }
>> +}
>> +
>> +/**
>> +  This function is called by all processors (both BSP and AP) once 
>> and collects
>> +  MP related data.
>> +
>> +  @param BSP            TRUE if the processor is the BSP.
>> +  @param Mpidr          The MPIDR for the specified processor. This 
>> should be
>> +                        the full MPIDR and not only the affinity bits.
>> +  @param ProcessorIndex The index of the processor.
>> +
>> +  @return EFI_SUCCESS if the data for the processor collected and 
>> filled in.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +FillInProcessorInformation (
>> +  IN BOOLEAN  BSP,
>> +  IN UINTN    Mpidr,
>> +  IN UINTN    ProcessorIndex
>> +  )
>> +{
>> +  EFI_PROCESSOR_INFORMATION  *CpuInfo;
>> +
>> +  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
>> +
>> +  CpuInfo->ProcessorId = GET_MPIDR_AFFINITY_BITS (Mpidr);
>> +  CpuInfo->StatusFlag  = PROCESSOR_ENABLED_BIT | 
>> PROCESSOR_HEALTH_STATUS_BIT;
>> +
>> +  if (BSP) {
>> +    CpuInfo->StatusFlag |= PROCESSOR_AS_BSP_BIT;
>> +  }
>> +
>> +  if ((Mpidr & MPIDR_MT_BIT) > 0) {
>> +    CpuInfo->Location.Package = GET_MPIDR_AFF2 (Mpidr);
>> +    CpuInfo->Location.Core    = GET_MPIDR_AFF1 (Mpidr);
>> +    CpuInfo->Location.Thread  = GET_MPIDR_AFF0 (Mpidr);
>> +
>> +    CpuInfo->ExtendedInformation.Location2.Package = GET_MPIDR_AFF3 
>> (Mpidr);
>> +    CpuInfo->ExtendedInformation.Location2.Die     = GET_MPIDR_AFF2 
>> (Mpidr);
>> +    CpuInfo->ExtendedInformation.Location2.Core    = GET_MPIDR_AFF1 
>> (Mpidr);
>> +    CpuInfo->ExtendedInformation.Location2.Thread  = GET_MPIDR_AFF0 
>> (Mpidr);
>> +  } else {
>> +    CpuInfo->Location.Package = GET_MPIDR_AFF1 (Mpidr);
>> +    CpuInfo->Location.Core    = GET_MPIDR_AFF0 (Mpidr);
>> +    CpuInfo->Location.Thread  = 0;
>> +
>> +    CpuInfo->ExtendedInformation.Location2.Package = GET_MPIDR_AFF2 
>> (Mpidr);
>> +    CpuInfo->ExtendedInformation.Location2.Die     = GET_MPIDR_AFF1 
>> (Mpidr);
>> +    CpuInfo->ExtendedInformation.Location2.Core    = GET_MPIDR_AFF0 
>> (Mpidr);
>> +    CpuInfo->ExtendedInformation.Location2.Thread  = 0;
>> +  }
>> +
>> +  mCpuMpData.CpuData[ProcessorIndex].State = BSP ? CpuStateBusy : 
>> CpuStateIdle;
>> +
>> +  mCpuMpData.CpuData[ProcessorIndex].Procedure = NULL;
>> +  mCpuMpData.CpuData[ProcessorIndex].Parameter = NULL;
>> +
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +/** Initializes the MP Services system data
>> +
>> +   @param NumberOfProcessors The number of processors, both BSP and AP.
>> +   @param CoreInfo           CPU information gathered earlier during 
>> boot.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +MpServicesInitialize (
>> +  IN   UINTN                NumberOfProcessors,
>> +  IN   CONST ARM_CORE_INFO  *CoreInfo
>> +  )
>> +{
>> +  EFI_STATUS  Status;
>> +  UINTN       Index;
>> +  EFI_EVENT   ReadyToBootEvent;
>> +  BOOLEAN     IsBsp;
> [KQ]: Can we add a check to see if BSP is found during this routine? I 
> think failing to identify a BSP might cause other issues in the 
> following services?
>> +
>> +  //
>> +  // Clear the data structure area first.
>> +  //
>> +  ZeroMem (&mCpuMpData, sizeof (CPU_MP_DATA));
>> +  //
>> +  // First BSP fills and inits all known values, including its own 
>> records.
>> +  //
>> +  mCpuMpData.NumberOfProcessors        = NumberOfProcessors;
>> +  mCpuMpData.NumberOfEnabledProcessors = NumberOfProcessors;
>> +
>> +  mCpuMpData.CpuData = AllocateZeroPool (
>> +                         mCpuMpData.NumberOfProcessors * sizeof 
>> (CPU_AP_DATA)
>> +                         );
>> +
>> +  if (mCpuMpData.CpuData == NULL) {
>> +    return EFI_OUT_OF_RESOURCES;
>> +  }
>> +
>> +  /* Allocate one extra for the sentinel entry at the end */
>> +  gProcessorIDs = AllocatePool ((mCpuMpData.NumberOfProcessors + 1) 
>> * sizeof (UINT64));
>> +  ASSERT (gProcessorIDs != NULL);
>> +
>> +  Status = gBS->CreateEvent (
>> +                  EVT_TIMER | EVT_NOTIFY_SIGNAL,
>> +                  TPL_CALLBACK,
>> +                  CheckAllAPsStatus,
>> +                  NULL,
>> +                  &mCpuMpData.CheckAllAPsEvent
>> +                  );
>> +  ASSERT_EFI_ERROR (Status);
>> +
>> +  gApStacksBase = AllocatePages (
>> +                    EFI_SIZE_TO_PAGES (
>> +                      mCpuMpData.NumberOfProcessors *
>> +                      gApStackSize
>> +                      )
>> +                    );
>> +  ASSERT (gApStacksBase != NULL);
>> +
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    if (GET_MPIDR_AFFINITY_BITS (ArmReadMpidr ()) == 
>> CoreInfo[Index].Mpidr) {
> [KQ]: Does this mean BSP should never set the `MPIDR_MT_BIT` in the 
> gArmMpCoreInfoGuid HOB data? Otherwise, this logic will never be able 
> to find the BSP?
>> +      IsBsp = TRUE;
>> +    } else {
>> +      IsBsp = FALSE;
>> +    }
>> +
>> +    FillInProcessorInformation (IsBsp, CoreInfo[Index].Mpidr, Index);
>> +
>> +    gProcessorIDs[Index] = mCpuMpData.CpuData[Index].Info.ProcessorId;
>> +
>> +    Status = gBS->CreateEvent (
>> +                    EVT_TIMER | EVT_NOTIFY_SIGNAL,
>> +                    TPL_CALLBACK,
>> +                    CheckThisAPStatus,
>> +                    (VOID *)&mCpuMpData.CpuData[Index],
>> + &mCpuMpData.CpuData[Index].CheckThisAPEvent
>> +                    );
>> +    ASSERT_EFI_ERROR (Status);
>> +  }
>> +
>> +  gProcessorIDs[Index] = MAX_UINT64;
>> +
>> +  //
>> +  // The global pointer variables as well as the gProcessorIDs array 
>> contents
>> +  // are accessed by the other cores so we must clean them to the PoC
>> +  //
>> +  WriteBackDataCacheRange (&gProcessorIDs, sizeof (UINT64 *));
>> +  WriteBackDataCacheRange (&gApStacksBase, sizeof (UINT64 *));
>> +
>> +  WriteBackDataCacheRange (
>> +    gProcessorIDs,
>> +    (mCpuMpData.NumberOfProcessors + 1) * sizeof (UINT64)
>> +    );
>> +
>> +  Status = EfiCreateEventReadyToBootEx (
>> +             TPL_CALLBACK,
>> +             ReadyToBootSignaled,
>> +             NULL,
>> +             &ReadyToBootEvent
>> +             );
>> +  ASSERT_EFI_ERROR (Status);
>> +
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +/**
>> +  Event notification function called when the 
>> EFI_EVENT_GROUP_READY_TO_BOOT is
>> +  signaled. After this point, non-blocking mode is no longer allowed.
>> +
>> +  @param  Event     Event whose notification function is being invoked.
>> +  @param  Context   The pointer to the notification function's context,
>> +                    which is implementation-dependent.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +EFIAPI
>> +ReadyToBootSignaled (
>> +  IN  EFI_EVENT  Event,
>> +  IN  VOID       *Context
>> +  )
>> +{
>> +  mNonBlockingModeAllowed = FALSE;
>> +}
>> +
>> +/** Initialize multi-processor support.
>> +
>> +  @param ImageHandle  Image handle.
>> +  @param SystemTable  System table.
>> +
>> +  @return EFI_SUCCESS on success, or an error code.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +ArmPsciMpServicesDxeInitialize (
>> +  IN EFI_HANDLE        ImageHandle,
>> +  IN EFI_SYSTEM_TABLE  *SystemTable
>> +  )
>> +{
>> +  EFI_STATUS                 Status;
>> +  EFI_HANDLE                 Handle;
>> +  UINTN                      MaxCpus;
>> +  EFI_LOADED_IMAGE_PROTOCOL  *Image;
>> +  EFI_HOB_GENERIC_HEADER     *Hob;
>> +  VOID                       *HobData;
>> +  UINTN                      HobDataSize;
>> +  CONST ARM_CORE_INFO        *CoreInfo;
>> +
>> +  MaxCpus = 1;
>> +
>> +  DEBUG ((DEBUG_INFO, "Starting MP services\n"));
>> +
>> +  Status = gBS->HandleProtocol (
>> +                  ImageHandle,
>> +                  &gEfiLoadedImageProtocolGuid,
>> +                  (VOID **)&Image
>> +                  );
>> +  ASSERT_EFI_ERROR (Status);
>> +
>> +  //
>> +  // Parts of the code in this driver may be executed by other cores 
>> running
>> +  // with the MMU off so we need to ensure that everything is clean 
>> to the
>> +  // point of coherency (PoC)
>> +  //
>> +  WriteBackDataCacheRange (Image->ImageBase, Image->ImageSize);
>> +
>> +  Status = gBS->HandleProtocol (
>> +                  ImageHandle,
>> +                  &gEfiLoadedImageProtocolGuid,
>> +                  (VOID **)&Image
>> +                  );
>> +  ASSERT_EFI_ERROR (Status);
>> +
>> +  //
>> +  // Parts of the code in this driver may be executed by other cores 
>> running
>> +  // with the MMU off so we need to ensure that everything is clean 
>> to the
>> +  // point of coherency (PoC)
>> +  //
>> +  WriteBackDataCacheRange (Image->ImageBase, Image->ImageSize);
>> +
>> +  Hob = GetFirstGuidHob (&gArmMpCoreInfoGuid);
>> +  if (Hob != NULL) {
>> +    HobData     = GET_GUID_HOB_DATA (Hob);
>> +    HobDataSize = GET_GUID_HOB_DATA_SIZE (Hob);
>> +    CoreInfo    = (ARM_CORE_INFO *)HobData;
>> +    MaxCpus     = HobDataSize / sizeof (ARM_CORE_INFO);
>> +  }
>> +
>> +  if (MaxCpus == 1) {
>> +    DEBUG ((DEBUG_WARN, "Trying to use EFI_MP_SERVICES_PROTOCOL on a 
>> UP system"));
>> +    // We are not MP so nothing to do
>> +    return EFI_NOT_FOUND;
>> +  }
>> +
>> +  Status = MpServicesInitialize (MaxCpus, CoreInfo);
>> +  if (Status != EFI_SUCCESS) {
>> +    ASSERT_EFI_ERROR (Status);
>> +    return Status;
>> +  }
>> +
>> +  //
>> +  // Now install the MP services protocol.
>> +  //
>> +  Handle = NULL;
>> +  Status = gBS->InstallMultipleProtocolInterfaces (
>> +                  &Handle,
>> +                  &gEfiMpServiceProtocolGuid,
>> +                  &mMpServicesProtocol,
>> +                  NULL
>> +                  );
>> +  ASSERT_EFI_ERROR (Status);
>> +  return Status;
>> +}
>> +
>> +/** C entry-point for the AP.
>> +    This function gets called from the assembly function ApEntryPoint.
>> +
>> +**/
>> +VOID
>> +ApProcedure (
>> +  VOID
>> +  )
>> +{
>> +  ARM_SMC_ARGS      Args;
>> +  EFI_AP_PROCEDURE  UserApProcedure;
>> +  VOID              *UserApParameter;
>> +  UINTN             ProcessorIndex;
>> +
>> +  WhoAmI (&mMpServicesProtocol, &ProcessorIndex);
>> +
>> +  /* Fetch the user-supplied procedure and parameter to execute */
>> +  UserApProcedure = mCpuMpData.CpuData[ProcessorIndex].Procedure;
>> +  UserApParameter = mCpuMpData.CpuData[ProcessorIndex].Parameter;
>> +
>> +  // Configure the MMU and caches
>> +  ArmSetTCR (mCpuMpData.CpuData[ProcessorIndex].Tcr);
>> +  ArmSetTTBR0 (mCpuMpData.CpuData[ProcessorIndex].Ttbr0);
>> +  ArmSetMAIR (mCpuMpData.CpuData[ProcessorIndex].Mair);
>> +  ArmDisableAlignmentCheck ();
>> +  ArmEnableStackAlignmentCheck ();
>> +  ArmEnableInstructionCache ();
>> +  ArmEnableDataCache ();
>> +  ArmEnableMmu ();
>> +
>> +  UserApProcedure (UserApParameter);
>> +
>> +  mCpuMpData.CpuData[ProcessorIndex].State = CpuStateFinished;
>> +
>> +  ArmDataMemoryBarrier ();
>> +
>> +  /* Since we're finished with this AP, turn it off */
>> +  Args.Arg0 = ARM_SMC_ID_PSCI_CPU_OFF;
>> +  ArmCallSmc (&Args);
>> +
>> +  /* Should never be reached */
>> +  ASSERT (FALSE);
>> +  CpuDeadLoop ();
>> +}
>> +
>> +/** Returns whether the processor executing this function is the BSP.
>> +
>> +    @return Whether the current processor is the BSP.
>> +**/
>> +STATIC
>> +BOOLEAN
>> +IsCurrentProcessorBSP (
>> +  VOID
>> +  )
>> +{
>> +  EFI_STATUS  Status;
>> +  UINTN       ProcessorIndex;
>> +
>> +  Status = WhoAmI (&mMpServicesProtocol, &ProcessorIndex);
>> +  if (EFI_ERROR (Status)) {
>> +    ASSERT_EFI_ERROR (Status);
>> +    return FALSE;
>> +  }
>> +
>> +  return IsProcessorBSP (ProcessorIndex);
>> +}
>> +
>> +/** Returns whether the specified processor is enabled.
>> +
>> +   @param[in] ProcessorIndex The index of the processor to check.
>> +
>> +   @return TRUE if the processor is enabled, FALSE otherwise.
>> +**/
>> +STATIC
>> +BOOLEAN
>> +IsProcessorEnabled (
>> +  UINTN  ProcessorIndex
>> +  )
>> +{
>> +  EFI_PROCESSOR_INFORMATION  *CpuInfo;
>> +
>> +  CpuInfo = &mCpuMpData.CpuData[ProcessorIndex].Info;
>> +
>> +  return (CpuInfo->StatusFlag & PROCESSOR_ENABLED_BIT) != 0;
>> +}
>> +
>> +/** Returns whether all processors are in the idle state.
>> +
>> +   @return Whether all the processors are idle.
>> +
>> +**/
>> +STATIC
>> +BOOLEAN
>> +CheckAllCpusReady (
>> +  VOID
>> +  )
>> +{
>> +  UINTN        Index;
>> +  CPU_AP_DATA  *CpuData;
>> +
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    CpuData = &mCpuMpData.CpuData[Index];
>> +    if (IsProcessorBSP (Index)) {
>> +      // Skip BSP
>> +      continue;
>> +    }
>> +
>> +    if (!IsProcessorEnabled (Index)) {
>> +      // Skip Disabled processors
>> +      continue;
>> +    }
>> +
>> +    if (GetApState (CpuData) != CpuStateIdle) {
>> +      return FALSE;
>> +    }
>> +  }
>> +
>> +  return TRUE;
>> +}
>> +
>> +/** Sets up the state for the StartupAllAPs function.
>> +
>> +   @param SingleThread Whether the APs will execute sequentially.
>> +
>> +**/
>> +STATIC
>> +VOID
>> +StartupAllAPsPrepareState (
>> +  IN BOOLEAN  SingleThread
>> +  )
>> +{
>> +  UINTN        Index;
>> +  CPU_STATE    APInitialState;
>> +  CPU_AP_DATA  *CpuData;
>> +
>> +  mCpuMpData.FinishCount  = 0;
>> +  mCpuMpData.StartCount   = 0;
>> +  mCpuMpData.SingleThread = SingleThread;
>> +
>> +  APInitialState = CpuStateReady;
>> +
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    CpuData = &mCpuMpData.CpuData[Index];
>> +
>> +    //
>> +    // Get APs prepared, and put failing APs into FailedCpuList.
>> +    // If "SingleThread", only 1 AP will put into ready state, other 
>> AP will be
>> +    // put into ready state 1 by 1, until the previous 1 finished 
>> its task.
>> +    // If not "SingleThread", all APs are put into ready state from the
>> +    // beginning
>> +    //
>> +
>> +    if (IsProcessorBSP (Index)) {
>> +      // Skip BSP
>> +      continue;
>> +    }
>> +
>> +    if (!IsProcessorEnabled (Index)) {
>> +      // Skip Disabled processors
>> +      if (mCpuMpData.FailedList != NULL) {
>> +        mCpuMpData.FailedList[mCpuMpData.FailedListIndex++] = Index;
>> +      }
>> +
>> +      continue;
>> +    }
>> +
>> +    ASSERT (GetApState (CpuData) == CpuStateIdle);
>> +    CpuData->State = APInitialState;
>> +
>> +    mCpuMpData.StartCount++;
>> +    if (SingleThread) {
>> +      APInitialState = CpuStateBlocked;
>> +    }
>> +  }
>> +}
>> +
>> +/** Handles execution of StartupAllAPs when a WaitEvent has been 
>> specified.
>> +
>> +   @param Procedure         The user-supplied procedure.
>> +   @param ProcedureArgument The user-supplied procedure argument.
>> +   @param WaitEvent         The wait event to be signaled when the 
>> work is
>> +                            complete or a timeout has occurred.
>> +   @param TimeoutInMicroseconds The timeout for the work to be 
>> completed. Zero
>> +                                indicates an infinite timeout.
>> +
>> +   @return EFI_SUCCESS on success.
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +StartupAllAPsWithWaitEvent (
>> +  IN EFI_AP_PROCEDURE  Procedure,
>> +  IN VOID              *ProcedureArgument,
>> +  IN EFI_EVENT         WaitEvent,
>> +  IN UINTN             TimeoutInMicroseconds
>> +  )
>> +{
>> +  EFI_STATUS   Status;
>> +  UINTN        Index;
>> +  CPU_AP_DATA  *CpuData;
>> +
>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    CpuData = &mCpuMpData.CpuData[Index];
>> +    if (IsProcessorBSP (Index)) {
>> +      // Skip BSP
>> +      continue;
>> +    }
>> +
>> +    if (!IsProcessorEnabled (Index)) {
>> +      // Skip Disabled processors
>> +      continue;
>> +    }
>> +
>> +    if (GetApState (CpuData) == CpuStateReady) {
>> +      SetApProcedure (CpuData, Procedure, ProcedureArgument);
>> +    }
>> +  }
>> +
>> +  //
>> +  // Save data into private data structure, and create timer to poll 
>> AP state
>> +  // before exiting
>> +  //
>> +  mCpuMpData.Procedure         = Procedure;
>> +  mCpuMpData.ProcedureArgument = ProcedureArgument;
>> +  mCpuMpData.WaitEvent         = WaitEvent;
>> +  mCpuMpData.Timeout           = TimeoutInMicroseconds;
>> +  mCpuMpData.TimeoutActive     = (BOOLEAN)(TimeoutInMicroseconds != 0);
>> +  Status                       = gBS->SetTimer (
>> + mCpuMpData.CheckAllAPsEvent,
>> +                                        TimerPeriodic,
>> +                                        POLL_INTERVAL_US
>> +                                        );
>> +  return Status;
>> +}
>> +
>> +/** Handles execution of StartupAllAPs when no wait event has been 
>> specified.
>> +
>> +   @param Procedure             The user-supplied procedure.
>> +   @param ProcedureArgument     The user-supplied procedure argument.
>> +   @param TimeoutInMicroseconds The timeout for the work to be 
>> completed. Zero
>> +                                indicates an infinite timeout.
>> +   @param SingleThread          Whether the APs will execute 
>> sequentially.
>> +   @param FailedCpuList         User-supplied pointer for list of 
>> failed CPUs.
>> +
>> +   @return EFI_SUCCESS on success.
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +StartupAllAPsNoWaitEvent (
>> +  IN EFI_AP_PROCEDURE  Procedure,
>> +  IN VOID              *ProcedureArgument,
>> +  IN UINTN             TimeoutInMicroseconds,
>> +  IN BOOLEAN           SingleThread,
>> +  IN UINTN             **FailedCpuList
>> +  )
>> +{
>> +  EFI_STATUS   Status;
>> +  UINTN        Index;
>> +  UINTN        NextIndex;
>> +  UINTN        Timeout;
>> +  CPU_AP_DATA  *CpuData;
>> +
>> +  Timeout = TimeoutInMicroseconds;
>> +
>> +  while (TRUE) {
>> +    for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +      CpuData = &mCpuMpData.CpuData[Index];
>> +      if (IsProcessorBSP (Index)) {
>> +        // Skip BSP
>> +        continue;
>> +      }
>> +
>> +      if (!IsProcessorEnabled (Index)) {
>> +        // Skip Disabled processors
>> +        continue;
>> +      }
>> +
>> +      switch (GetApState (CpuData)) {
>> +        case CpuStateReady:
>> +          SetApProcedure (CpuData, Procedure, ProcedureArgument);
>> +          Status = DispatchCpu (Index);
>> +          if (EFI_ERROR (Status)) {
>> +            CpuData->State = CpuStateIdle;
>> +            Status         = EFI_NOT_READY;
>> +            goto Done;
> [KQ]: Is it really necessary to use "goto Done"? This might cause all 
> the CPUs after this failing index to not reset the CPU state.
> That way, all the subsequent "StartupAllAps" will fail due to 
> "CheckAllCpusReady" returning FALSE on those "dirty cores". Please
> let me know if that is by design or not.
>> +          }
>> +
>> +          break;
>> +
>> +        case CpuStateFinished:
>> +          mCpuMpData.FinishCount++;
>> +          if (SingleThread) {
>> +            Status = GetNextBlockedNumber (&NextIndex);
>> +            if (!EFI_ERROR (Status)) {
>> +              mCpuMpData.CpuData[NextIndex].State = CpuStateReady;
>> +            }
>> +          }
>> +
>> +          CpuData->State = CpuStateIdle;
>> +          break;
>> +
>> +        default:
>> +          break;
>> +      }
>> +    }
>> +
>> +    if (mCpuMpData.FinishCount == mCpuMpData.StartCount) {
>> +      Status = EFI_SUCCESS;
>> +      goto Done;
>> +    }
>> +
>> +    if ((TimeoutInMicroseconds != 0) && (Timeout == 0)) {
>> +      Status = EFI_TIMEOUT;
>> +      goto Done;
>> +    }
>> +
>> +    Timeout -= CalculateAndStallInterval (Timeout);
>> +  }
>> +
>> +Done:
>> +  if (FailedCpuList != NULL) {
>> +    if (mCpuMpData.FailedListIndex == 0) {
>> +      FreePool (*FailedCpuList);
>> +      *FailedCpuList = NULL;
>> +    }
>> +  }
>> +
>> +  return Status;
>> +}
>> diff --git a/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S 
>> b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S
>> new file mode 100644
>> index 000000000000..a90fa8a0075f
>> --- /dev/null
>> +++ b/ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S
>> @@ -0,0 +1,57 @@
>> +#=============================================================================== 
>>
>> +#  Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights 
>> reserved.
>> +#
>> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
>> +#=============================================================================== 
>>
>> +
>> +.text
>> +.align 3
>> +
>> +#include <AsmMacroIoLibV8.h>
>> +#include <IndustryStandard/ArmStdSmc.h>
>> +
>> +#include "MpServicesInternal.h"
>> +
>> +GCC_ASM_IMPORT (gApStacksBase)
>> +GCC_ASM_IMPORT (gProcessorIDs)
>> +GCC_ASM_IMPORT (ApProcedure)
>> +GCC_ASM_IMPORT (gApStackSize)
>> +
>> +GCC_ASM_EXPORT (ApEntryPoint)
>> +
>> +// Entry-point for the AP
>> +// VOID
>> +// ApEntryPoint (
>> +//   VOID
>> +//   );
>> +ASM_PFX(ApEntryPoint):
>> +  mrs x0, mpidr_el1
>> +  // Mask the non-affinity bits
>> +  bic x0, x0, 0x00ff000000
>> +  and x0, x0, 0xffffffffff
>> +  ldr x1, gProcessorIDs
>> +  mov x2, 0                   // x2 = processor index
>> +
>> +// Find index in gProcessorIDs for current processor
>> +1:
>> +  ldr x3, [x1, x2, lsl #3]    // x4 = gProcessorIDs + x2 * 8
>> +  cmp x3, #-1                 // check if we've reached the end of 
>> gProcessorIDs
>> +  beq ProcessorNotFound
>> +  add x2, x2, 1               // x2++
>> +  cmp x0, x3                  // if mpidr_el1 != gProcessorIDs[x] 
>> then loop
>> +  bne 1b
>> +
>> +// Calculate stack address
>> +  // x2 contains the index for the current processor plus 1
>> +  ldr x0, gApStacksBase
>> +  ldr x1, gApStackSize
>> +  mul x3, x2, x1              // x3 = (ProcessorIndex + 1) * 
>> gApStackSize
>> +  add sp, x0, x3              // sp = gApStacksBase + x3
>> +  mov x29, xzr
>> +  bl ApProcedure              // doesn't return
>> +
>> +ProcessorNotFound:
>> +// Turn off the processor
>> +  MOV32 (w0, ARM_SMC_ID_PSCI_CPU_OFF)
>> +  smc #0
>> +  b .

Re: [edk2-devel] [PATCH 1/2] ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls

[Rebecca Cran]

On 11/28/22 15:59, Kun Qin wrote:
> Hi Rebecca/Ard,
> 
> I was trying to reach out regarding the original patches earlier (see 
> below) but it might fell off your stacks
> due to high traffic on the mailing list. Could you please kindly review 
> the questions when you have a chance?
> 
> In addition, I found another edge case of the MP service: when the AP 
> routine hits a timeout, the metadata
> will be left in the unfinished states. If the AP routine eventually 
> completes and return, this AP will stay in "finished"
> but never become "ready" during this boot. I tried to add below change, 
> which seems to work. But please let me
> know if you have other concerns:
> https://github.com/kuqin12/mu_silicon_arm_tiano/commit/c76072b37018276f2fec2582d0c540be5b40d0f2

Thanks, I'll take a look and integrate the fix into the next revision of 
the patch series.

> 
> Lastly, do you plan to merge these patches in the near future? This will 
> be a great add-on for ARM platforms.

The issue that's currently preventing them from being merged is a 
failure I noticed on the Neoverse N2 FVP: for some reason despite 
enabling the MMU and caches, manual cache flushes are still required for 
the data to be seen between CPUs. I don't know if that's a bug in the 
code or in the FVP model.

-- 
Rebecca Cran

Re: [edk2-devel] [PATCH 1/2] ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls

[Kun Qin]

Thanks for the update, Rebecca. I will also keep an eye on the cache 
issue when I have a chance to run this on FVP models.

Regards,
Kun

On 11/28/2022 4:04 PM, Rebecca Cran wrote:
> On 11/28/22 15:59, Kun Qin wrote:
>> Hi Rebecca/Ard,
>>
>> I was trying to reach out regarding the original patches earlier (see 
>> below) but it might fell off your stacks
>> due to high traffic on the mailing list. Could you please kindly 
>> review the questions when you have a chance?
>>
>> In addition, I found another edge case of the MP service: when the AP 
>> routine hits a timeout, the metadata
>> will be left in the unfinished states. If the AP routine eventually 
>> completes and return, this AP will stay in "finished"
>> but never become "ready" during this boot. I tried to add below 
>> change, which seems to work. But please let me
>> know if you have other concerns:
>> https://github.com/kuqin12/mu_silicon_arm_tiano/commit/c76072b37018276f2fec2582d0c540be5b40d0f2 
>>
>
> Thanks, I'll take a look and integrate the fix into the next revision 
> of the patch series.
>
>>
>> Lastly, do you plan to merge these patches in the near future? This 
>> will be a great add-on for ARM platforms.
>
> The issue that's currently preventing them from being merged is a 
> failure I noticed on the Neoverse N2 FVP: for some reason despite 
> enabling the MMU and caches, manual cache flushes are still required 
> for the data to be seen between CPUs. I don't know if that's a bug in 
> the code or in the FVP model.
>

Re: [edk2-devel] [PATCH 1/2] ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls

[Rebecca Cran]

Sorry, I missed this originally. I've added my replies inline.][

On 9/29/22 12:45, Kun Qin wrote:
> Hi Rebecca,
> 
> Thanks for sending this patch. I have a few questions inline "[KQ]". 
> Could you please help me to
> understand the patch better? Thanks in advance.
> 
> Regards,
> Kun
> 
> On 8/29/2022 8:59 AM, Rebecca Cran wrote:

>> +#define GET_MPIDR_AFFINITY_BITS(x)  ((x) & 0xFF00FFFFFF)
>> +
>> +#define MPIDR_MT_BIT  BIT24
> [KQ]: Is there any reason why this is not defined in a more formal 
> place? I think that will allow the platform to use as well.

That's a good point. I can certainly move it somewhere more proper.

>> +  BOOLEAN     IsBsp;
> [KQ]: Can we add a check to see if BSP is found during this routine? I 
> think failing to identify a BSP might cause other issues in the 
> following services?

We could certainly log an error and abort if IsBsp is never set to TRUE.

>> +  for (Index = 0; Index < mCpuMpData.NumberOfProcessors; Index++) {
>> +    if (GET_MPIDR_AFFINITY_BITS (ArmReadMpidr ()) == 
>> CoreInfo[Index].Mpidr) {
> [KQ]: Does this mean BSP should never set the `MPIDR_MT_BIT` in the 
> gArmMpCoreInfoGuid HOB data? Otherwise, this logic will never be able to 
> find the BSP?

No, here we assume we're running on the BSP, and the code is looking for 
the entry in the CoreInfo array that matches the BSP's affinity fields.

>> +      switch (GetApState (CpuData)) {
>> +        case CpuStateReady:
>> +          SetApProcedure (CpuData, Procedure, ProcedureArgument);
>> +          Status = DispatchCpu (Index);
>> +          if (EFI_ERROR (Status)) {
>> +            CpuData->State = CpuStateIdle;
>> +            Status         = EFI_NOT_READY;
>> +            goto Done;
> [KQ]: Is it really necessary to use "goto Done"? This might cause all 
> the CPUs after this failing index to not reset the CPU state.
> That way, all the subsequent "StartupAllAps" will fail due to 
> "CheckAllCpusReady" returning FALSE on those "dirty cores". Please
> let me know if that is by design or not.

Good point. I'll fix it.


-- 
Rebecca Cran

[PATCH 2/2] MdeModulePkg: Add new Application/MpServicesTest application

[Rebecca Cran]

The MpServicesTest application exercises the EFI_MP_SERVICES_PROTOCOL.

usage:
  MpServicesTest -A [-O]
  MpServicesTest -T <Timeout>
  MpServicesTest -S <Processor #>
  MpServicesTest -P
  MpServicesTest -U <Processor #>
  MpServicesTest -W
  MpServicesTest -E <Processor #>
  MpServicesTest -D <Processor #>
  MpServicesTest -h

Parameter:
  -A:  Run all APs.
  -O:  Run APs sequentially (use with -A).
  -T:  Specify timeout in milliseconds. Default is to wait forever.
  -S:  Specify the single AP to run.
  -P:  Print processor information.
  -U:  Set the specified AP to the Unhealthy status (use with -E/-D).
  -W:  Run WhoAmI and print index of BSP.
  -E:  Enable the specified AP.
  -D:  Disable the specified AP.
  -h:  Print this help page.

Signed-off-by: Rebecca Cran <rebecca@quicinc.com>
---
 MdeModulePkg/MdeModulePkg.dsc                              |   9 +
 MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf |  41 ++
 MdeModulePkg/Application/MpServicesTest/Options.h          |  39 ++
 MdeModulePkg/Application/MpServicesTest/MpServicesTest.c   | 558 ++++++++++++++++++++
 MdeModulePkg/Application/MpServicesTest/Options.c          | 215 ++++++++
 5 files changed, 862 insertions(+)

diff --git a/MdeModulePkg/MdeModulePkg.dsc b/MdeModulePkg/MdeModulePkg.dsc
index 45a8ec84ad69..2444cd2927a2 100644
--- a/MdeModulePkg/MdeModulePkg.dsc
+++ b/MdeModulePkg/MdeModulePkg.dsc
@@ -166,6 +166,7 @@ [LibraryClasses.common.UEFI_APPLICATION]
   MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
   DebugLib|MdePkg/Library/UefiDebugLibStdErr/UefiDebugLibStdErr.inf
   FileHandleLib|MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.inf
+  ShellLib|ShellPkg/Library/UefiShellLib/UefiShellLib.inf
 
 [LibraryClasses.common.MM_STANDALONE]
   HobLib|MdeModulePkg/Library/BaseHobLibNull/BaseHobLibNull.inf
@@ -512,9 +513,17 @@ [Components.IA32, Components.X64]
   MdeModulePkg/Universal/RegularExpressionDxe/RegularExpressionDxe.inf
   MdeModulePkg/Universal/SmmCommunicationBufferDxe/SmmCommunicationBufferDxe.inf
   MdeModulePkg/Universal/Disk/RamDiskDxe/RamDiskDxe.inf
+  MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf
 
 [Components.X64]
   MdeModulePkg/Universal/CapsulePei/CapsuleX64.inf
 
+[Components.AARCH64]
+  MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf {
+    <LibraryClasses>
+      CacheMaintenanceLib|ArmPkg/Library/ArmCacheMaintenanceLib/ArmCacheMaintenanceLib.inf
+      ShellLib|ShellPkg/Library/UefiShellLib/UefiShellLib.inf
+  }
+
 [BuildOptions]
 
diff --git a/MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf b/MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf
new file mode 100644
index 000000000000..25d5666a5fec
--- /dev/null
+++ b/MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf
@@ -0,0 +1,41 @@
+## @file
+#  UEFI Application to exercise EFI_MP_SERVICES_PROTOCOL.
+#
+#  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 1.29
+  BASE_NAME                      = MpServicesTest
+  FILE_GUID                      = 43e9defa-7209-4b0d-b136-cc4ca02cb469
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 0.1
+  ENTRY_POINT                    = UefiMain
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
+#
+
+[Sources]
+  MpServicesTest.c
+  Options.c
+  Options.h
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  CacheMaintenanceLib
+  ShellLib
+  UefiApplicationEntryPoint
+  UefiLib
+
+[Protocols]
+  gEfiMpServiceProtocolGuid    ## CONSUMES
+
diff --git a/MdeModulePkg/Application/MpServicesTest/Options.h b/MdeModulePkg/Application/MpServicesTest/Options.h
new file mode 100644
index 000000000000..cb28230ab095
--- /dev/null
+++ b/MdeModulePkg/Application/MpServicesTest/Options.h
@@ -0,0 +1,39 @@
+/** @file
+  Options handling code.
+
+  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef MPSERVICESTEST_OPTIONS_H_
+#define MPSERVICESTEST_OPTIONS_H_
+
+#define INFINITE_TIMEOUT  0
+
+typedef struct {
+  UINTN      Timeout;
+  UINTN      ProcessorIndex;
+  BOOLEAN    RunAllAPs;
+  BOOLEAN    RunSingleAP;
+  BOOLEAN    DisableProcessor;
+  BOOLEAN    EnableProcessor;
+  BOOLEAN    SetProcessorHealthy;
+  BOOLEAN    SetProcessorUnhealthy;
+  BOOLEAN    PrintProcessorInformation;
+  BOOLEAN    PrintBspProcessorIndex;
+  BOOLEAN    RunAPsSequentially;
+} MP_SERVICES_TEST_OPTIONS;
+
+/**
+  Parses any arguments provided on the command line.
+
+  @param Options  The arguments structure.
+
+  @return EFI_SUCCESS on success, or an error code.
+**/
+EFI_STATUS
+ParseArguments (
+  MP_SERVICES_TEST_OPTIONS  *Options
+  );
+
+#endif /* MPSERVICESTEST_OPTIONS_H_ */
diff --git a/MdeModulePkg/Application/MpServicesTest/MpServicesTest.c b/MdeModulePkg/Application/MpServicesTest/MpServicesTest.c
new file mode 100644
index 000000000000..82dbac700884
--- /dev/null
+++ b/MdeModulePkg/Application/MpServicesTest/MpServicesTest.c
@@ -0,0 +1,558 @@
+/** @file
+  UEFI Application to exercise EFI_MP_SERVICES_PROTOCOL.
+
+  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Uefi.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/CacheMaintenanceLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PrintLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+#include <Pi/PiMultiPhase.h>
+#include <Protocol/MpService.h>
+
+#include "Options.h"
+
+#define APFUNC_BUFFER_LEN  256
+
+typedef struct {
+  EFI_MP_SERVICES_PROTOCOL    *Mp;
+  CHAR16                      **Buffer;
+} APFUNC_ARG;
+
+/** The procedure to run with the MP Services interface.
+
+  @param Arg The procedure argument.
+
+**/
+STATIC
+VOID
+EFIAPI
+ApFunction (
+  IN OUT VOID  *Arg
+  )
+{
+  APFUNC_ARG  *Param;
+  UINTN       ProcessorId;
+
+  if (Arg != NULL) {
+    Param = Arg;
+
+    Param->Mp->WhoAmI (Param->Mp, &ProcessorId);
+    UnicodeSPrint (Param->Buffer[ProcessorId], APFUNC_BUFFER_LEN, L"Hello from CPU %ld\n", ProcessorId);
+  }
+}
+
+/**
+  Fetches the number of processors and which processor is the BSP.
+
+  @param Mp  MP Services Protocol.
+  @param NumProcessors Number of processors.
+  @param BspIndex      The index of the BSP.
+**/
+STATIC
+EFI_STATUS
+GetProcessorInformation (
+  IN  EFI_MP_SERVICES_PROTOCOL  *Mp,
+  OUT UINTN                     *NumProcessors,
+  OUT UINTN                     *BspIndex
+  )
+{
+  EFI_STATUS  Status;
+  UINTN       NumEnabledProcessors;
+
+  Status = Mp->GetNumberOfProcessors (Mp, NumProcessors, &NumEnabledProcessors);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = Mp->WhoAmI (Mp, BspIndex);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/** Displays information returned from MP Services Protocol.
+
+  @param Mp       The MP Services Protocol
+  @param BspIndex On return, contains the index of the BSP.
+
+  @return The number of CPUs in the system.
+
+**/
+STATIC
+UINTN
+PrintProcessorInformation (
+  IN   EFI_MP_SERVICES_PROTOCOL  *Mp,
+  OUT  UINTN                     *BspIndex
+  )
+{
+  EFI_STATUS                 Status;
+  EFI_PROCESSOR_INFORMATION  CpuInfo;
+  UINTN                      Index;
+  UINTN                      NumCpu;
+  UINTN                      NumEnabledCpu;
+
+  Status = Mp->GetNumberOfProcessors (Mp, &NumCpu, &NumEnabledCpu);
+  if (EFI_ERROR (Status)) {
+    Print (L"GetNumberOfProcessors failed: %r\n", Status);
+  } else {
+    Print (L"Number of CPUs: %ld, Enabled: %d\n", NumCpu, NumEnabledCpu);
+  }
+
+  for (Index = 0; Index < NumCpu; Index++) {
+    Status = Mp->GetProcessorInfo (Mp, CPU_V2_EXTENDED_TOPOLOGY | Index, &CpuInfo);
+    if (EFI_ERROR (Status)) {
+      Print (L"GetProcessorInfo for Processor %d failed: %r\n", Index, Status);
+    } else {
+      Print (
+        L"Processor %d:\n"
+        L"\tID: %016lx\n"
+        L"\tStatus: %s | ",
+        Index,
+        CpuInfo.ProcessorId,
+        (CpuInfo.StatusFlag & PROCESSOR_AS_BSP_BIT) ? L"BSP" : L"AP"
+        );
+
+      if ((CpuInfo.StatusFlag & PROCESSOR_AS_BSP_BIT) && (BspIndex != NULL)) {
+        *BspIndex = Index;
+      }
+
+      Print (L"%s | ", (CpuInfo.StatusFlag & PROCESSOR_ENABLED_BIT) ? L"Enabled" : L"Disabled");
+      Print (L"%s\n", (CpuInfo.StatusFlag & PROCESSOR_HEALTH_STATUS_BIT) ? L"Healthy" : L"Faulted");
+
+      Print (
+        L"\tLocation: Package %d, Core %d, Thread %d\n"
+        L"\tExtended Information: Package %d, Module %d, Tile %d, Die %d, Core %d, Thread %d\n\n",
+        CpuInfo.Location.Package,
+        CpuInfo.Location.Core,
+        CpuInfo.Location.Thread,
+        CpuInfo.ExtendedInformation.Location2.Package,
+        CpuInfo.ExtendedInformation.Location2.Module,
+        CpuInfo.ExtendedInformation.Location2.Tile,
+        CpuInfo.ExtendedInformation.Location2.Die,
+        CpuInfo.ExtendedInformation.Location2.Core,
+        CpuInfo.ExtendedInformation.Location2.Thread
+        );
+    }
+  }
+
+  return NumCpu;
+}
+
+/** Allocates memory in ApArg for the single AP specified.
+
+  @param ApArg          Pointer to the AP argument structure.
+  @param Mp             The MP Services Protocol.
+  @param ProcessorIndex The index of the AP.
+
+  @retval EFI_SUCCESS          Memory was successfully allocated.
+  @retval EFI_OUT_OF_RESOURCES Failed to allocate memory.
+
+**/
+STATIC
+EFI_STATUS
+AllocateApFuncBufferSingleAP (
+  IN APFUNC_ARG                *ApArg,
+  IN EFI_MP_SERVICES_PROTOCOL  *Mp,
+  IN UINTN                     ProcessorIndex
+  )
+{
+  ApArg->Mp = Mp;
+
+  ApArg->Buffer = AllocateZeroPool ((ProcessorIndex + 1) * sizeof (VOID *));
+  if (ApArg->Buffer == NULL) {
+    Print (L"Failed to allocate buffer for AP buffer\n");
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  ApArg->Buffer[ProcessorIndex] = AllocateZeroPool (APFUNC_BUFFER_LEN);
+  if (ApArg->Buffer[ProcessorIndex] == NULL) {
+    Print (L"Failed to allocate buffer for AP buffer\n");
+    FreePool (ApArg->Buffer);
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/** Allocates memory in ApArg for all APs.
+
+  @param ApArg   Pointer to the AP argument structure.
+  @param Mp      The MP Services Protocol.
+  @param NumCpus The number of CPUs.
+
+  @retval EFI_SUCCESS          Memory was successfully allocated.
+  @retval EFI_OUT_OF_RESOURCES Failed to allocate memory.
+
+**/
+STATIC
+EFI_STATUS
+AllocateApFuncBufferAllAPs (
+  IN APFUNC_ARG                *ApArg,
+  IN EFI_MP_SERVICES_PROTOCOL  *Mp,
+  IN UINTN                     NumCpus
+  )
+{
+  INT32  Index;
+
+  ApArg->Mp = Mp;
+
+  ApArg->Buffer = AllocateZeroPool (NumCpus * sizeof (VOID *));
+  if (ApArg->Buffer == NULL) {
+    Print (L"Failed to allocate buffer for AP message\n");
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  for (Index = 0; Index < NumCpus; Index++) {
+    ApArg->Buffer[Index] = AllocateZeroPool (APFUNC_BUFFER_LEN);
+    if (ApArg->Buffer[Index] == NULL) {
+      Print (L"Failed to allocate buffer for AP message\n");
+      for (--Index; Index >= 0; Index++) {
+        FreePool (ApArg->Buffer[Index]);
+      }
+
+      FreePool (ApArg->Buffer);
+      return EFI_OUT_OF_RESOURCES;
+    }
+  }
+
+  return EFI_SUCCESS;
+}
+
+/** Frees memory in ApArg for all APs.
+
+  @param ApArg   Pointer to the AP argument structure.
+  @param NumCpus The number of CPUs.
+
+**/
+STATIC
+VOID
+FreeApFuncBuffer (
+  APFUNC_ARG  *ApArg,
+  UINTN       NumCpus
+  )
+{
+  UINTN  Index;
+
+  for (Index = 0; Index < NumCpus; Index++) {
+    if (ApArg->Buffer[Index] != NULL) {
+      FreePool (ApArg->Buffer[Index]);
+    }
+  }
+
+  FreePool (ApArg->Buffer);
+}
+
+/** Runs a specified AP.
+
+  @param Mp             The MP Services Protocol.
+  @param ProcessorIndex The processor index.
+  @param Timeout        Timeout in milliseconds.
+
+  @return EFI_SUCCESS on success, or an error code.
+
+**/
+STATIC
+EFI_STATUS
+StartupThisAP (
+  IN EFI_MP_SERVICES_PROTOCOL  *Mp,
+  IN UINTN                     ProcessorIndex,
+  IN UINTN                     Timeout
+  )
+{
+  EFI_STATUS  Status;
+  APFUNC_ARG  ApArg;
+
+  Status = AllocateApFuncBufferSingleAP (&ApArg, Mp, ProcessorIndex);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = AllocateApFuncBufferSingleAP (&ApArg, Mp, ProcessorIndex);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Print (
+    L"StartupThisAP on Processor %d with %d%s timeout...",
+    ProcessorIndex,
+    Timeout,
+    (Timeout == INFINITE_TIMEOUT) ? " (infinite)" : "ms"
+    );
+  Status = Mp->StartupThisAP (
+                 Mp,
+                 ApFunction,
+                 ProcessorIndex,
+                 NULL,
+                 Timeout * 1000,
+                 &ApArg,
+                 NULL
+                 );
+  if (EFI_ERROR (Status)) {
+    Print (L"failed: %r\n", Status);
+    return Status;
+  } else {
+    Print (L"done.\n");
+    Print (ApArg.Buffer[ProcessorIndex]);
+  }
+
+  FreeApFuncBuffer (&ApArg, ProcessorIndex + 1);
+
+  return EFI_SUCCESS;
+}
+
+/** Runs all APs.
+
+  @param Mp                 The MP Services Protocol.
+  @param NumCpus            The number of CPUs in the system.
+  @param Timeout            Timeout in milliseconds.
+  @param RunAPsSequentially Run APs sequentially (FALSE: run simultaneously)
+
+  @return EFI_SUCCESS on success, or an error code.
+
+**/
+STATIC
+EFI_STATUS
+StartupAllAPs (
+  IN EFI_MP_SERVICES_PROTOCOL  *Mp,
+  IN UINTN                     NumCpus,
+  IN UINTN                     Timeout,
+  IN BOOLEAN                   RunAPsSequentially
+  )
+{
+  EFI_STATUS  Status;
+  UINTN       Index;
+  APFUNC_ARG  ApArg;
+
+  Status = AllocateApFuncBufferAllAPs (&ApArg, Mp, NumCpus);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Print (
+    L"Running with SingleThread TRUE, %dms timeout...",
+    Timeout,
+    (Timeout == INFINITE_TIMEOUT) ? " (infinite)" : "ms"
+    );
+  Status = Mp->StartupAllAPs (
+                 Mp,
+                 ApFunction,
+                 RunAPsSequentially,
+                 NULL,
+                 Timeout * 1000,
+                 &ApArg,
+                 NULL
+                 );
+  if (EFI_ERROR (Status)) {
+    Print (L"failed: %r\n", Status);
+    return Status;
+  } else {
+    Print (L"done.\n");
+    for (Index = 0; Index < NumCpus; Index++) {
+      Print (ApArg.Buffer[Index]);
+    }
+  }
+
+  FreeApFuncBuffer (&ApArg, NumCpus);
+  return EFI_SUCCESS;
+}
+
+/**
+  Enables the specified AP.
+
+  @param Mp               The MP Services Protocol.
+  @param ProcessorIndex   The processor to enable.
+  @param ProcessorHealthy The health status of the processor.
+
+  @return EFI_SUCCESS on success, or an error code.
+**/
+STATIC
+EFI_STATUS
+EnableAP (
+  IN EFI_MP_SERVICES_PROTOCOL  *Mp,
+  UINTN                        ProcessorIndex,
+  BOOLEAN                      ProcessorHealthy
+  )
+{
+  EFI_STATUS  Status;
+  UINT32      HealthFlag;
+
+  if (ProcessorHealthy) {
+    Print (L"Enabling Processor %d with HealthFlag healthy...", ProcessorIndex);
+    HealthFlag = PROCESSOR_HEALTH_STATUS_BIT;
+  } else {
+    Print (L"Enabling Processor %d with HealthFlag faulted...", ProcessorIndex);
+    HealthFlag = 0;
+  }
+
+  Status = Mp->EnableDisableAP (Mp, ProcessorIndex, TRUE, &HealthFlag);
+  if (EFI_ERROR (Status)) {
+    Print (L"failed: %r\n", Status);
+    return Status;
+  } else {
+    Print (L"done.\n");
+  }
+
+  return Status;
+}
+
+/**
+  Disables the specified AP.
+
+  @param Mp               The MP Services Protocol.
+  @param ProcessorIndex   The processor to disable.
+  @param ProcessorHealthy The health status of the processor.
+
+  @return EFI_SUCCESS on success, or an error code.
+**/
+STATIC
+EFI_STATUS
+DisableAP (
+  IN EFI_MP_SERVICES_PROTOCOL  *Mp,
+  UINTN                        ProcessorIndex,
+  BOOLEAN                      ProcessorHealthy
+  )
+{
+  EFI_STATUS  Status;
+  UINT32      HealthFlag;
+
+  if (ProcessorHealthy) {
+    Print (L"Disabling Processor %d with HealthFlag healthy...", ProcessorIndex);
+    HealthFlag = PROCESSOR_HEALTH_STATUS_BIT;
+  } else {
+    Print (L"Disabling Processor %d with HealthFlag faulted...", ProcessorIndex);
+    HealthFlag = 0;
+  }
+
+  Status = Mp->EnableDisableAP (Mp, ProcessorIndex, FALSE, &HealthFlag);
+  if (EFI_ERROR (Status)) {
+    Print (L"failed: %r\n", Status);
+    return Status;
+  } else {
+    Print (L"done.\n");
+  }
+
+  return Status;
+}
+
+/**
+  The user Entry Point for Application. The user code starts with this function
+  as the real entry point for the application.
+
+  @param[in] ImageHandle    The firmware allocated handle for the EFI image.
+  @param[in] SystemTable    A pointer to the EFI System Table.
+
+  @retval EFI_SUCCESS       The entry point is executed successfully.
+  @retval other             Some error occurs when executing this entry point.
+
+**/
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS                Status;
+  EFI_MP_SERVICES_PROTOCOL  *Mp;
+  UINTN                     BspIndex;
+  UINTN                     CpuIndex;
+  UINTN                     NumCpus;
+  BOOLEAN                   ProcessorHealthy;
+  MP_SERVICES_TEST_OPTIONS  Options;
+
+  WriteBackDataCacheRange ((VOID *)&ApFunction, 32);
+
+  BspIndex = 0;
+
+  Status = gBS->LocateProtocol (
+                  &gEfiMpServiceProtocolGuid,
+                  NULL,
+                  (VOID **)&Mp
+                  );
+  if (EFI_ERROR (Status)) {
+    Print (L"Failed to locate EFI_MP_SERVICES_PROTOCOL (%r). Not installed on platform?\n", Status);
+    return EFI_NOT_FOUND;
+  }
+
+  Status = ParseArguments (&Options);
+  if (EFI_ERROR (Status)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Status = GetProcessorInformation (Mp, &NumCpus, &BspIndex);
+  if (EFI_ERROR (Status)) {
+    Print (L"Error: Failed to fetch processor information.\n");
+    return Status;
+  }
+
+  if (Options.PrintBspProcessorIndex) {
+    Status = Mp->WhoAmI (Mp, &CpuIndex);
+    if (EFI_ERROR (Status)) {
+      Print (L"WhoAmI failed: %r\n", Status);
+      return Status;
+    } else {
+      Print (L"BSP: %016lx\n", CpuIndex);
+    }
+  }
+
+  if (Options.PrintProcessorInformation) {
+    NumCpus = PrintProcessorInformation (Mp, &BspIndex);
+    if (NumCpus < 2) {
+      Print (L"Error: Uniprocessor system found.\n");
+      return EFI_INVALID_PARAMETER;
+    }
+  }
+
+  if (Options.RunSingleAP) {
+    Status = StartupThisAP (
+               Mp,
+               Options.ProcessorIndex,
+               Options.Timeout
+               );
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+  }
+
+  if (Options.RunAllAPs) {
+    Status = StartupAllAPs (Mp, NumCpus, Options.Timeout, Options.RunAPsSequentially);
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+  }
+
+  if (Options.EnableProcessor) {
+    ProcessorHealthy = TRUE;
+    if (Options.SetProcessorUnhealthy) {
+      ProcessorHealthy = FALSE;
+    }
+
+    Status = EnableAP (Mp, Options.ProcessorIndex, ProcessorHealthy);
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+  }
+
+  if (Options.DisableProcessor) {
+    ProcessorHealthy = TRUE;
+    if (Options.SetProcessorUnhealthy) {
+      ProcessorHealthy = FALSE;
+    }
+
+    Status = DisableAP (Mp, Options.ProcessorIndex, ProcessorHealthy);
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/MdeModulePkg/Application/MpServicesTest/Options.c b/MdeModulePkg/Application/MpServicesTest/Options.c
new file mode 100644
index 000000000000..7380ca44daf7
--- /dev/null
+++ b/MdeModulePkg/Application/MpServicesTest/Options.c
@@ -0,0 +1,215 @@
+/** @file
+  Options handling code.
+
+  Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.<BR>
+  Copyright (c) 2010-2019  Finnbarr P. Murphy.   All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Uefi.h>
+#include <Library/BaseMemoryLib.h>
+#include <Protocol/ShellParameters.h>
+#include <Library/BaseLib.h>
+#include <Library/UefiLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+#include "Options.h"
+
+STATIC UINTN   Argc;
+STATIC CHAR16  **Argv;
+
+/**
+
+  This function provides argc and argv.
+
+  @return Status
+**/
+EFI_STATUS
+GetArg (
+  VOID
+  )
+{
+  EFI_STATUS                     Status;
+  EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters;
+
+  Status = gBS->HandleProtocol (
+                  gImageHandle,
+                  &gEfiShellParametersProtocolGuid,
+                  (VOID **)&ShellParameters
+                  );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Argc = ShellParameters->Argc;
+  Argv = ShellParameters->Argv;
+  return EFI_SUCCESS;
+}
+
+/**
+  Checks if the character is a decimal digit.
+
+  @param Char The character to check.
+
+  @return TRUE if the character is a decimal digit.
+**/
+BOOLEAN
+IsUnicodeDecimalDigit (
+  CHAR16  Char
+  )
+{
+  return ((BOOLEAN)(Char >= L'0' && Char <= L'9'));
+}
+
+/**
+  Converts the string to an integer.
+
+  @param String The input string.
+  @param Value  The converted number.
+
+  @return EFI_SUCCESS on success, or an error code.
+**/
+EFI_STATUS
+UnicodeStringToInteger (
+  CHAR16  *String,
+  UINTN   *Value
+  )
+{
+  UINTN  Result;
+
+  Result = 0;
+
+  if ((String == NULL) || (StrSize (String) == 0) || (Value == NULL)) {
+    return (EFI_INVALID_PARAMETER);
+  }
+
+  while (IsUnicodeDecimalDigit (*String)) {
+    if (!(Result <= (DivU64x32 ((((UINT64) ~0) - (*String - L'0')), 10)))) {
+      return (EFI_DEVICE_ERROR);
+    }
+
+    Result = MultU64x32 (Result, 10) + (*String - L'0');
+    String++;
+  }
+
+  *Value = Result;
+
+  return (EFI_SUCCESS);
+}
+
+/**
+  Print app usage.
+**/
+STATIC
+VOID
+PrintUsage (
+  VOID
+  )
+{
+  Print (L"MpServicesTest:  usage\n");
+  Print (L"  MpServicesTest -A [-O]\n");
+  Print (L"  MpServicesTest -T <Timeout>\n");
+  Print (L"  MpServicesTest -S <Processor #>\n");
+  Print (L"  MpServicesTest -P\n");
+  Print (L"  MpServicesTest -U <Processor #>\n");
+  Print (L"  MpServicesTest -W\n");
+  Print (L"  MpServicesTest -E <Processor #>\n");
+  Print (L"  MpServicesTest -D <Processor #>\n");
+  Print (L"  MpServicesTest -h\n");
+  Print (L"Parameter:\n");
+  Print (L"  -A:  Run all APs.\n");
+  Print (L"  -O:  Run APs sequentially (use with -A).\n");
+  Print (L"  -T:  Specify timeout in milliseconds. Default is to wait forever.\n");
+  Print (L"  -S:  Specify the single AP to run.\n");
+  Print (L"  -P:  Print processor information.\n");
+  Print (L"  -U:  Set the specified AP to the Unhealthy status (use with -E/-D).\n");
+  Print (L"  -W:  Run WhoAmI and print index of BSP.\n");
+  Print (L"  -E:  Enable the specified AP.\n");
+  Print (L"  -D:  Disable the specified AP.\n");
+  Print (L"  -h:  Print this help page.\n");
+}
+
+/**
+  Parses any arguments provided on the command line.
+
+  @param Options  The arguments structure.
+
+  @return EFI_SUCCESS on success, or an error code.
+**/
+EFI_STATUS
+ParseArguments (
+  MP_SERVICES_TEST_OPTIONS  *Options
+  )
+{
+  EFI_STATUS    Status;
+  INT32         ArgIndex;
+  CONST CHAR16  *Argument;
+  BOOLEAN       NeedsValue;
+  UINTN         *Value;
+
+  Status = GetArg ();
+  if (EFI_ERROR (Status)) {
+    Print (L"Please use the UEFI Shell to run this application!\n", Status);
+    return Status;
+  }
+
+  if (Argc == 1) {
+    PrintUsage ();
+  }
+
+  ZeroMem (Options, sizeof (MP_SERVICES_TEST_OPTIONS));
+
+  for (ArgIndex = 1; ArgIndex < Argc; ArgIndex++) {
+    Argument   = Argv[ArgIndex];
+    NeedsValue = FALSE;
+
+    if (StrCmp (Argument, L"-A") == 0) {
+      Options->RunAllAPs = TRUE;
+    } else if (StrCmp (Argument, L"-O") == 0) {
+      Options->RunAPsSequentially = TRUE;
+    } else if (StrCmp (Argument, L"-T") == 0) {
+      NeedsValue = TRUE;
+      Value      = &Options->Timeout;
+    } else if (StrCmp (Argument, L"-S") == 0) {
+      Options->RunSingleAP = TRUE;
+      NeedsValue           = TRUE;
+      Value                = &Options->ProcessorIndex;
+    } else if (StrCmp (Argument, L"-P") == 0) {
+      Options->PrintProcessorInformation = TRUE;
+    } else if (StrCmp (Argument, L"-U") == 0) {
+      Options->SetProcessorUnhealthy = TRUE;
+    } else if (StrCmp (Argument, L"-W") == 0) {
+      Options->PrintBspProcessorIndex = TRUE;
+    } else if (StrCmp (Argument, L"-E") == 0) {
+      Options->EnableProcessor = TRUE;
+      NeedsValue               = TRUE;
+      Value                    = &Options->ProcessorIndex;
+    } else if (StrCmp (Argument, L"-D") == 0) {
+      Options->DisableProcessor = TRUE;
+      NeedsValue                = TRUE;
+      Value                     = &Options->ProcessorIndex;
+    } else {
+      PrintUsage ();
+      ZeroMem (Options, sizeof (MP_SERVICES_TEST_OPTIONS));
+      return EFI_SUCCESS;
+    }
+
+    if (NeedsValue) {
+      if ((ArgIndex + 1) < Argc) {
+        Status = UnicodeStringToInteger (Argv[ArgIndex + 1], Value);
+        if (EFI_ERROR (Status)) {
+          Print (L"Error: option value must be a positive integer.\n");
+          PrintUsage ();
+          return EFI_INVALID_PARAMETER;
+        }
+
+        ArgIndex++;
+      } else {
+        PrintUsage ();
+        return EFI_INVALID_PARAMETER;
+      }
+    }
+  }
+
+  return EFI_SUCCESS;
+}
-- 
2.30.2

Re: [PATCH 2/2] MdeModulePkg: Add new Application/MpServicesTest application

[Rebecca Cran]

On 8/29/22 09:59, Rebecca Cran wrote:
> +/**
> +  Print app usage.
> +**/
> +STATIC
> +VOID
> +PrintUsage (
> +  VOID
> +  )
> +{
> +  Print (L"MpServicesTest:  usage\n");
> +  Print (L"  MpServicesTest -A [-O]\n");
> +  Print (L"  MpServicesTest -T <Timeout>\n");
> +  Print (L"  MpServicesTest -S <Processor #>\n");
> +  Print (L"  MpServicesTest -P\n");
> +  Print (L"  MpServicesTest -U <Processor #>\n");
> +  Print (L"  MpServicesTest -W\n");
> +  Print (L"  MpServicesTest -E <Processor #>\n");
> +  Print (L"  MpServicesTest -D <Processor #>\n");

The -U option doesn't take a processor# parameter, since it's used with -E/-D where that's specified.

I'll fix this in patch 2.

-- 

Rebecca Cran

Re: [edk2-devel] [PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Ard Biesheuvel]

On Mon, 29 Aug 2022 at 18:00, Rebecca Cran <quic_rcran@quicinc.com> wrote:
>
> This is the rework of the patches I sent out in late 2021,
> building on fixes done by Ard at
> https://github.com/ardbiesheuvel/edk2/tree/armpkg-mpservicesdxe-refactor.
>
> The most significant changes are the addition of code to enable
> the MMU and caches on the APs, and changing MpServicesTest to
> use commandline parameters to control its operation.
>

IIRC, there were some issues with this code on bare metal. Which
hardware did you use to test it? Any chance you could try it on a
RPi4?

> Rebecca Cran (2):
>   ArmPkg: implement EFI_MP_SERVICES_PROTOCOL based on PSCI calls
>   MdeModulePkg: Add new Application/MpServicesTest application
>
>  ArmPkg/ArmPkg.dsc                                            |    1 +
>  MdeModulePkg/MdeModulePkg.dsc                                |    9 +
>  ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf |   55 +
>  MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf   |   41 +
>  ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h     |  351 ++++
>  MdeModulePkg/Application/MpServicesTest/Options.h            |   39 +
>  ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c   | 1774 ++++++++++++++++++++
>  MdeModulePkg/Application/MpServicesTest/MpServicesTest.c     |  558 ++++++
>  MdeModulePkg/Application/MpServicesTest/Options.c            |  215 +++
>  ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S                |   57 +
>  10 files changed, 3100 insertions(+)
>  create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.inf
>  create mode 100644 MdeModulePkg/Application/MpServicesTest/MpServicesTest.inf
>  create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpServicesInternal.h
>  create mode 100644 MdeModulePkg/Application/MpServicesTest/Options.h
>  create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c
>  create mode 100644 MdeModulePkg/Application/MpServicesTest/MpServicesTest.c
>  create mode 100644 MdeModulePkg/Application/MpServicesTest/Options.c
>  create mode 100644 ArmPkg/Drivers/ArmPsciMpServicesDxe/MpFuncs.S
>
> --
> 2.30.2
>
>
>
> 
>
>

Re: [edk2-devel] [PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Rebecca Cran]

On 9/5/22 04:57, Ard Biesheuvel wrote:
>
> IIRC, there were some issues with this code on bare metal. Which
> hardware did you use to test it? Any chance you could try it on a
> RPi4?

Yes, there were. I've run this code on an Arm Juno R2, Synquacer Developer Box and SolidRun HoneyComb.
I do have an RPi4 I can use, so I'll test it on that too.

-- 
Rebecca Cran

Re: [edk2-devel] [PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Ard Biesheuvel]

On Mon, 5 Sept 2022 at 17:52, Rebecca Cran <quic_rcran@quicinc.com> wrote:
>
> On 9/5/22 04:57, Ard Biesheuvel wrote:
> >
> > IIRC, there were some issues with this code on bare metal. Which
> > hardware did you use to test it? Any chance you could try it on a
> > RPi4?
>
> Yes, there were. I've run this code on an Arm Juno R2, Synquacer Developer Box and SolidRun HoneyComb.
> I do have an RPi4 I can use, so I'll test it on that too.
>

I think you've got things covered: I suggested RPi4 because it uses
A72, and I seem to remember the issues I observed were either on A57
or A72 (which are quite similar). But between Juno and HoneyComb, I
don't think the RPi4 data point is that useful.

Re: [edk2-devel] [PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Ard Biesheuvel]

On Mon, 5 Sept 2022 at 17:55, Ard Biesheuvel <ardb@kernel.org> wrote:
>
> On Mon, 5 Sept 2022 at 17:52, Rebecca Cran <quic_rcran@quicinc.com> wrote:
> >
> > On 9/5/22 04:57, Ard Biesheuvel wrote:
> > >
> > > IIRC, there were some issues with this code on bare metal. Which
> > > hardware did you use to test it? Any chance you could try it on a
> > > RPi4?
> >
> > Yes, there were. I've run this code on an Arm Juno R2, Synquacer Developer Box and SolidRun HoneyComb.
> > I do have an RPi4 I can use, so I'll test it on that too.
> >
>
> I think you've got things covered: I suggested RPi4 because it uses
> A72, and I seem to remember the issues I observed were either on A57
> or A72 (which are quite similar). But between Juno and HoneyComb, I
> don't think the RPi4 data point is that useful.

For the series,

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

Re: [edk2-devel] [PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Rebecca Cran]

On 9/5/22 09:55, Ard Biesheuvel wrote:
> I think you've got things covered: I suggested RPi4 because it uses
> A72, and I seem to remember the issues I observed were either on A57
> or A72 (which are quite similar). But between Juno and HoneyComb, I
> don't think the RPi4 data point is that useful.

My only concern is about the call in MpServicesTest:

WriteBackDataCacheRange ((VOID *)&ApFunction, 32);

Obviously the '32' is a magic number and should be something based on the size of ApFunction.
But I don't think there's a portable way to calculate what that value should be.

-- 
Rebecca Cran

Re: [edk2-devel] [PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Ard Biesheuvel]

On Tue, 6 Sept 2022 at 19:01, Rebecca Cran <quic_rcran@quicinc.com> wrote:
>
> On 9/5/22 09:55, Ard Biesheuvel wrote:
> > I think you've got things covered: I suggested RPi4 because it uses
> > A72, and I seem to remember the issues I observed were either on A57
> > or A72 (which are quite similar). But between Juno and HoneyComb, I
> > don't think the RPi4 data point is that useful.
>
> My only concern is about the call in MpServicesTest:
>
> WriteBackDataCacheRange ((VOID *)&ApFunction, 32);
>
> Obviously the '32' is a magic number and should be something based on the size of ApFunction.
> But I don't think there's a portable way to calculate what that value should be.
>

Why exactly do we need that call?

I understand that some of the code needs to be clean to the PoC (on
ARM) so that the AP can fetch instructions with the MMU and caches
disabled. But the actual routine passed into the API is called with
the MMU and caches on, right?

Re: [edk2-devel] [PATCH 0/2] Add support EFI_MP_SERVICES_PROTOCOL on AARCH64

[Rebecca Cran]

On 9/6/22 11:53, Ard Biesheuvel wrote:
> On Tue, 6 Sept 2022 at 19:01, Rebecca Cran <quic_rcran@quicinc.com> wrote:
>> My only concern is about the call in MpServicesTest:
>>
>> WriteBackDataCacheRange ((VOID *)&ApFunction, 32);
>>
>> Obviously the '32' is a magic number and should be something based on the size of ApFunction.
>> But I don't think there's a portable way to calculate what that value should be.
>>
> Why exactly do we need that call?
>
> I understand that some of the code needs to be clean to the PoC (on
> ARM) so that the AP can fetch instructions with the MMU and caches
> disabled. But the actual routine passed into the API is called with
> the MMU and caches on, right?

It's a leftover from the work you did on the code, before I changed it to have the MMU and caches enabled on the APs.
I'll go through and remove it and any others for the v2 patch which I'll send out later today (which will also fix the Usage text for MpServicesTest).

-- 
Rebecca Cran