Re: [RFC 1/2] MdeModulePkg/EbcDxe: Add AARCH64 EBC VM support

[Daniil Egranov <daniil.egranov@arm.com>]

Hi Leif,


On 07/29/2016 11:06 AM, Leif Lindholm wrote:
> From: Jeff Brasen <jbrasen@codeaurora.org>
>
> Adds support for the EBC VM for AARCH64 platforms
>
> Submitted on behalf of a third-party: The Linux Foundation
> This contribution is licensed under the BSD license as found at
> http://opensource.org/licenses/bsd-license.php
>
> [Taken from https://source.codeaurora.org/external/server/edk2-blue/]
> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
> ---
>   .../Universal/EbcDxe/AArch64/EbcLowLevel.S         | 135 +++++
>   MdeModulePkg/Universal/EbcDxe/AArch64/EbcSupport.c | 563 +++++++++++++++++++++
>   MdeModulePkg/Universal/EbcDxe/EbcDxe.inf           |   6 +-
>   3 files changed, 703 insertions(+), 1 deletion(-)
>   create mode 100644 MdeModulePkg/Universal/EbcDxe/AArch64/EbcLowLevel.S
>   create mode 100644 MdeModulePkg/Universal/EbcDxe/AArch64/EbcSupport.c
>
> diff --git a/MdeModulePkg/Universal/EbcDxe/AArch64/EbcLowLevel.S b/MdeModulePkg/Universal/EbcDxe/AArch64/EbcLowLevel.S
> new file mode 100644
> index 0000000..e858227
> --- /dev/null
> +++ b/MdeModulePkg/Universal/EbcDxe/AArch64/EbcLowLevel.S
> @@ -0,0 +1,135 @@
> +#/** @file
> +#
> +#    This code provides low level routines that support the Virtual Machine
> +#   for option ROMs.
> +#
> +#  Copyright (c) 2015, The Linux Foundation. All rights reserved.
> +#  Copyright (c) 2007 - 2014, Intel Corporation. All rights reserved.<BR>
> +#  This program and the accompanying materials
> +#  are licensed and made available under the terms and conditions of the BSD License
> +#  which accompanies this distribution.  The full text of the license may be found at
> +#  http://opensource.org/licenses/bsd-license.php
> +#
> +#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +#
> +#**/
> +
> +#---------------------------------------------------------------------------
> +# Equate files needed.
> +#---------------------------------------------------------------------------
> +
> +ASM_GLOBAL ASM_PFX(CopyMem);
> +ASM_GLOBAL ASM_PFX(EbcInterpret);
> +ASM_GLOBAL ASM_PFX(ExecuteEbcImageEntryPoint);
> +
> +#****************************************************************************
> +# EbcLLCALLEX
> +#
> +# This function is called to execute an EBC CALLEX instruction.
> +# This instruction requires that we thunk out to external native
> +# code. For AArch64, we copy the VM stack into the main stack and then pop
> +# the first 8 arguments off according to the AArch64 Procedure Call Standard
> +# On return, we restore the stack pointer to its original location.
> +#
> +#****************************************************************************
> +# UINTN EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)
The code has a mix of using UINTN and UINT64 types. Even the 
ProcessorBind.h defines UINTN as UINT64 for Aarch64, this code is 
specific for the Aarch64 architecture. Should the UINT64 type be 
explicitly used instead of UINTN and avoid mixing of this types?
> +ASM_GLOBAL ASM_PFX(EbcLLCALLEXNative);
> +ASM_PFX(EbcLLCALLEXNative):
> +      stp  x19, x20, [sp, #-16]!
> +      stp  x29, x30, [sp, #-16]!
> +
> +      mov  x19, x0
> +      mov  x20, sp
> +      sub  x2, x2, x1   // Length = NewStackPointer-FramePtr
> +      sub  sp, sp, x2
> +      sub  sp, sp, #64  // Make sure there is room for at least 8 args in the new stack
> +      mov  x0, sp
> +
> +      bl   CopyMem      // Sp, NewStackPointer, Length
> +
> +      ldp  x0, x1, [sp], #16
> +      ldp  x2, x3, [sp], #16
> +      ldp  x4, x5, [sp], #16
> +      ldp  x6, x7, [sp], #16
> +
> +      blr  x19
> +
> +      mov  sp,  x20
> +      ldp  x29, x30, [sp], #16
> +      ldp  x19, x20, [sp], #16
> +
> +      ret
> +
> +#****************************************************************************
> +# EbcLLEbcInterpret
> +#
> +# This function is called by the thunk code to handle an Native to EBC call
> +# This can handle up to 16 arguments (1-8 on in x0-x7, 9-16 are on the stack)
> +# x9 contains the Entry point that will be the first argument when
> +# EBCInterpret is called.
> +#
> +#****************************************************************************
> +ASM_GLOBAL ASM_PFX(EbcLLEbcInterpret);
> +ASM_PFX(EbcLLEbcInterpret):
> +    stp  x29, x30, [sp, #-16]!
> +
> +    // copy the current arguments 9-16 from old location and add arg 7 to stack
> +    // keeping 16 byte stack alignment
> +    sub sp, sp, #80
> +    str x7, [sp]
> +    ldr x11, [sp, #96]
> +    str x11, [sp, #8]
> +    ldr x11, [sp, #104]
> +    str x11, [sp, #16]
> +    ldr x11, [sp, #112]
> +    str x11, [sp, #24]
> +    ldr x11, [sp, #120]
> +    str x11, [sp, #32]
> +    ldr x11, [sp, #128]
> +    str x11, [sp, #40]
> +    ldr x11, [sp, #136]
> +    str x11, [sp, #48]
> +    ldr x11, [sp, #144]
> +    str x11, [sp, #56]
> +    ldr x11, [sp, #152]
> +    str x11, [sp, #64]
> +
> +    // Shift arguments and add entry point and as argument 1
> +    mov x7, x6
> +    mov x6, x5
> +    mov x5, x4
> +    mov x4, x3
> +    mov x3, x2
> +    mov x2, x1
> +    mov x1, x0
> +    mov x0, x9
> +
> +    # call C-code
> +    bl ASM_PFX(EbcInterpret)
> +    add sp, sp, #80
> +
> +    ldp  x29, x30, [sp], #16
> +
> +    ret
> +
> +#****************************************************************************
> +# EbcLLExecuteEbcImageEntryPoint
> +#
> +# This function is called by the thunk code to handle the image entry point
> +# x9 contains the Entry point that will be the first argument when
> +# ExecuteEbcImageEntryPoint is called.
> +#
> +#****************************************************************************
> +ASM_GLOBAL ASM_PFX(EbcLLExecuteEbcImageEntryPoint);
> +ASM_PFX(EbcLLExecuteEbcImageEntryPoint):
> +    stp  x29, x30, [sp, #-16]!
> +    # build new paramater calling convention
> +    mov  x2, x1
> +    mov  x1, x0
> +    mov  x0, x9
> +
> +    # call C-code
> +    bl ASM_PFX(ExecuteEbcImageEntryPoint)
> +    ldp  x29, x30, [sp], #16
> +    ret
> diff --git a/MdeModulePkg/Universal/EbcDxe/AArch64/EbcSupport.c b/MdeModulePkg/Universal/EbcDxe/AArch64/EbcSupport.c
> new file mode 100644
> index 0000000..23261a0
> --- /dev/null
> +++ b/MdeModulePkg/Universal/EbcDxe/AArch64/EbcSupport.c
> @@ -0,0 +1,563 @@
> +/** @file
> +  This module contains EBC support routines that are customized based on
> +  the target AArch64 processor.
> +
> +Copyright (c) 2015, The Linux Foundation. All rights reserved.
> +Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
> +This program and the accompanying materials
> +are licensed and made available under the terms and conditions of the BSD License
> +which accompanies this distribution.  The full text of the license may be found at
> +http://opensource.org/licenses/bsd-license.php
> +
> +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#include "EbcInt.h"
> +#include "EbcExecute.h"
> +
> +//
> +// Amount of space that is not used in the stack
> +//
The "#define VM_STACK_SIZE ()" exists in Ia32, X64 and Ipf code but not 
here. However, it's not been used anywhere in the code directly. Is it 
safe to ignore it?
> +#define STACK_REMAIN_SIZE (1024 * 4)
> +
> +//
> +// This is instruction buffer used to create EBC thunk
> +//
> +#define EBC_MAGIC_SIGNATURE                0xCA112EBCCA112EBCull
> +#define EBC_ENTRYPOINT_SIGNATURE           0xAFAFAFAFAFAFAFAFull
> +#define EBC_LL_EBC_ENTRYPOINT_SIGNATURE    0xFAFAFAFAFAFAFAFAull
> +UINT8  mInstructionBufferTemplate[] = {
> +  0x03,  0x00, 0x00, 0x14, //b pc+16
> +  //
> +  // Add a magic code here to help the VM recognize the thunk..
> +  //
> +    (UINT8)(EBC_MAGIC_SIGNATURE & 0xFF),
> +    (UINT8)((EBC_MAGIC_SIGNATURE >> 8) & 0xFF),
> +    (UINT8)((EBC_MAGIC_SIGNATURE >> 16) & 0xFF),
> +    (UINT8)((EBC_MAGIC_SIGNATURE >> 24) & 0xFF),
> +    (UINT8)((EBC_MAGIC_SIGNATURE >> 32) & 0xFF),
> +    (UINT8)((EBC_MAGIC_SIGNATURE >> 40) & 0xFF),
> +    (UINT8)((EBC_MAGIC_SIGNATURE >> 48) & 0xFF),
> +    (UINT8)((EBC_MAGIC_SIGNATURE >> 56) & 0xFF),
> +  0x69, 0x00, 0x00, 0x58, //ldr x9, #32
> +  0x8A, 0x00, 0x00, 0x58, //ldr x10, #40
> +  0x05, 0x00, 0x00, 0x14, //b pc+32
> +    (UINT8)(EBC_ENTRYPOINT_SIGNATURE & 0xFF),
> +    (UINT8)((EBC_ENTRYPOINT_SIGNATURE >> 8) & 0xFF),
> +    (UINT8)((EBC_ENTRYPOINT_SIGNATURE >> 16) & 0xFF),
> +    (UINT8)((EBC_ENTRYPOINT_SIGNATURE >> 24) & 0xFF),
> +    (UINT8)((EBC_ENTRYPOINT_SIGNATURE >> 32) & 0xFF),
> +    (UINT8)((EBC_ENTRYPOINT_SIGNATURE >> 40) & 0xFF),
> +    (UINT8)((EBC_ENTRYPOINT_SIGNATURE >> 48) & 0xFF),
> +    (UINT8)((EBC_ENTRYPOINT_SIGNATURE >> 56) & 0xFF),
> +    (UINT8)(EBC_LL_EBC_ENTRYPOINT_SIGNATURE & 0xFF),
> +    (UINT8)((EBC_LL_EBC_ENTRYPOINT_SIGNATURE >> 8) & 0xFF),
> +    (UINT8)((EBC_LL_EBC_ENTRYPOINT_SIGNATURE >> 16) & 0xFF),
> +    (UINT8)((EBC_LL_EBC_ENTRYPOINT_SIGNATURE >> 24) & 0xFF),
> +    (UINT8)((EBC_LL_EBC_ENTRYPOINT_SIGNATURE >> 32) & 0xFF),
> +    (UINT8)((EBC_LL_EBC_ENTRYPOINT_SIGNATURE >> 40) & 0xFF),
> +    (UINT8)((EBC_LL_EBC_ENTRYPOINT_SIGNATURE >> 48) & 0xFF),
> +    (UINT8)((EBC_LL_EBC_ENTRYPOINT_SIGNATURE >> 56) & 0xFF),
> +  0x40, 0x01, 0x1F, 0xD6 //br x10
> +
> +};
This template may need additional comments explaining the code. There 
are couple of branching in the template above with jumping to PC+16 and 
PC+32. Are the 16 and 32 correct values?

Assuming that this template should have a similar functionality as x64 
template:
mov rax, 0xca112ebcca112ebc //store a magic signature (EBC_MAGIC_SIGNATURE)
mov r10, XXXXXXXXXXXXXXXX // store EBC entry point, the dummy address 
replaced with a valid address during runtime (EBC_ENTRYPOINT_SIGNATURE 
marker)
mov r11, XXXXXXXXXXXXXXXX //store VM function address,  the dummy 
address replaced with a valid address during runtime 
(EBC_LL_EBC_ENTRYPOINT_SIGNATURE marker)
jmp r11
> +
> +/**
> +  Begin executing an EBC image.
> +  This is used for Ebc Thunk call.
> +
> +  @return The value returned by the EBC application we're going to run.
> +
> +**/
> +UINT64
> +EFIAPI
> +EbcLLEbcInterpret (
> +  VOID
> +  );
> +
> +/**
> +  Begin executing an EBC image.
> +  This is used for Ebc image entrypoint.
> +
> +  @return The value returned by the EBC application we're going to run.
> +
> +**/
> +UINT64
> +EFIAPI
> +EbcLLExecuteEbcImageEntryPoint (
> +  VOID
> +  );
> +
> +/**
> +  Pushes a 64 bit unsigned value to the VM stack.
> +
> +  @param VmPtr  The pointer to current VM context.
> +  @param Arg    The value to be pushed.
> +
> +**/
> +VOID
> +PushU64 (
> +  IN VM_CONTEXT *VmPtr,
> +  IN UINT64     Arg
> +  )
> +{
> +  //
> +  // Advance the VM stack down, and then copy the argument to the stack.
> +  // Hope it's aligned.
> +  //
> +  VmPtr->Gpr[0] -= sizeof (UINT64);
> +  *(UINT64 *) VmPtr->Gpr[0] = Arg;
> +  return;
> +}
> +
> +
> +/**
> +  Begin executing an EBC image.
> +
> +  This is a thunk function.
> +
> +  @param  EntryPoint            The entrypoint of EBC code.
> +  @param  Arg1                  The 1st argument.
> +  @param  Arg2                  The 2nd argument.
> +  @param  Arg3                  The 3rd argument.
> +  @param  Arg4                  The 4th argument.
> +  @param  Arg5                  The 5th argument.
> +  @param  Arg6                  The 6th argument.
> +  @param  Arg7                  The 7th argument.
> +  @param  Arg8                  The 8th argument.
> +  @param  Arg9                  The 9th argument.
> +  @param  Arg10                 The 10th argument.
> +  @param  Arg11                 The 11th argument.
> +  @param  Arg12                 The 12th argument.
> +  @param  Arg13                 The 13th argument.
> +  @param  Arg14                 The 14th argument.
> +  @param  Arg15                 The 15th argument.
> +  @param  Arg16                 The 16th argument.
> +
> +  @return The value returned by the EBC application we're going to run.
> +
> +**/
> +UINT64
> +EFIAPI
> +EbcInterpret (
> +  IN UINTN      EntryPoint,
> +  IN UINTN      Arg1,
> +  IN UINTN      Arg2,
> +  IN UINTN      Arg3,
> +  IN UINTN      Arg4,
> +  IN UINTN      Arg5,
> +  IN UINTN      Arg6,
> +  IN UINTN      Arg7,
> +  IN UINTN      Arg8,
> +  IN UINTN      Arg9,
> +  IN UINTN      Arg10,
> +  IN UINTN      Arg11,
> +  IN UINTN      Arg12,
> +  IN UINTN      Arg13,
> +  IN UINTN      Arg14,
> +  IN UINTN      Arg15,
> +  IN UINTN      Arg16
> +  )
> +{
> +  //
> +  // Create a new VM context on the stack
> +  //
> +  VM_CONTEXT  VmContext;
> +  UINTN       Addr;
> +  EFI_STATUS  Status;
> +  UINTN       StackIndex;
> +
> +  //
> +  // Get the EBC entry point
> +  //
> +  Addr = EntryPoint;
> +
> +  //
> +  // Now clear out our context
> +  //
> +  ZeroMem ((VOID *) &VmContext, sizeof (VM_CONTEXT));
> +
> +  //
> +  // Set the VM instruction pointer to the correct location in memory.
> +  //
> +  VmContext.Ip = (VMIP) Addr;
> +
> +  //
> +  // Initialize the stack pointer for the EBC. Get the current system stack
> +  // pointer and adjust it down by the max needed for the interpreter.
> +  //
> +
> +  //
> +  // Adjust the VM's stack pointer down.
> +  //
> +
> +  Status = GetEBCStack((EFI_HANDLE)(UINTN)-1, &VmContext.StackPool, &StackIndex);
> +  if (EFI_ERROR(Status)) {
> +    return Status;
> +  }
> +  VmContext.StackTop = (UINT8*)VmContext.StackPool + (STACK_REMAIN_SIZE);
> +  VmContext.Gpr[0] = (UINT64) ((UINT8*)VmContext.StackPool + STACK_POOL_SIZE);
> +  VmContext.HighStackBottom = (UINTN) VmContext.Gpr[0];
> +  VmContext.Gpr[0] -= sizeof (UINTN);
> +
> +  //
> +  // Align the stack on a natural boundary.
> +  //
> +  VmContext.Gpr[0] &= ~(VM_REGISTER)(sizeof (UINTN) - 1);
This code is the same as x64. Is this correct alignment for Aarch64?
> +
> +  //
> +  // Put a magic value in the stack gap, then adjust down again.
> +  //
> +  *(UINTN *) (UINTN) (VmContext.Gpr[0]) = (UINTN) VM_STACK_KEY_VALUE;
> +  VmContext.StackMagicPtr             = (UINTN *) (UINTN) VmContext.Gpr[0];
> +
> +  //
> +  // The stack upper to LowStackTop is belong to the VM.
> +  //
> +  VmContext.LowStackTop   = (UINTN) VmContext.Gpr[0];
> +
> +  //
> +  // For the worst case, assume there are 4 arguments passed in registers, store
> +  // them to VM's stack.
> +  //
> +  PushU64 (&VmContext, (UINT64) Arg16);
> +  PushU64 (&VmContext, (UINT64) Arg15);
> +  PushU64 (&VmContext, (UINT64) Arg14);
> +  PushU64 (&VmContext, (UINT64) Arg13);
> +  PushU64 (&VmContext, (UINT64) Arg12);
> +  PushU64 (&VmContext, (UINT64) Arg11);
> +  PushU64 (&VmContext, (UINT64) Arg10);
> +  PushU64 (&VmContext, (UINT64) Arg9);
> +  PushU64 (&VmContext, (UINT64) Arg8);
> +  PushU64 (&VmContext, (UINT64) Arg7);
> +  PushU64 (&VmContext, (UINT64) Arg6);
> +  PushU64 (&VmContext, (UINT64) Arg5);
> +  PushU64 (&VmContext, (UINT64) Arg4);
> +  PushU64 (&VmContext, (UINT64) Arg3);
> +  PushU64 (&VmContext, (UINT64) Arg2);
> +  PushU64 (&VmContext, (UINT64) Arg1);
> +
> +  //
> +  // Interpreter assumes 64-bit return address is pushed on the stack.
> +  // AArch64 does not do this so pad the stack accordingly.
> +  //
> +  PushU64 (&VmContext, (UINT64) 0);
> +  PushU64 (&VmContext, (UINT64) 0x1234567887654321ULL);
> +
> +  //
> +  // For AArch64, this is where we say our return address is
> +  //
> +  VmContext.StackRetAddr  = (UINT64) VmContext.Gpr[0];
> +
> +  //
> +  // We need to keep track of where the EBC stack starts. This way, if the EBC
> +  // accesses any stack variables above its initial stack setting, then we know
> +  // it's accessing variables passed into it, which means the data is on the
> +  // VM's stack.
> +  // When we're called, on the stack (high to low) we have the parameters, the
> +  // return address, then the saved ebp. Save the pointer to the return address.
> +  // EBC code knows that's there, so should look above it for function parameters.
> +  // The offset is the size of locals (VMContext + Addr + saved ebp).
> +  // Note that the interpreter assumes there is a 16 bytes of return address on
> +  // the stack too, so adjust accordingly.
> +  //  VmContext.HighStackBottom = (UINTN)(Addr + sizeof (VmContext) + sizeof (Addr));
> +  //
> +
> +  //
> +  // Begin executing the EBC code
> +  //
> +  EbcExecute (&VmContext);
> +
> +  //
> +  // Return the value in R[7] unless there was an error
> +  //
> +  ReturnEBCStack(StackIndex);
> +  return (UINT64) VmContext.Gpr[7];
> +}
> +
> +
> +/**
> +  Begin executing an EBC image.
> +
> +  @param  EntryPoint       The entrypoint of EBC code.
> +  @param  ImageHandle      image handle for the EBC application we're executing
> +  @param  SystemTable      standard system table passed into an driver's entry
> +                           point
> +
> +  @return The value returned by the EBC application we're going to run.
> +
> +**/
> +UINT64
> +EFIAPI
> +ExecuteEbcImageEntryPoint (
> +  IN UINTN                EntryPoint,
> +  IN EFI_HANDLE           ImageHandle,
> +  IN EFI_SYSTEM_TABLE     *SystemTable
> +  )
> +{
> +  //
> +  // Create a new VM context on the stack
> +  //
> +  VM_CONTEXT  VmContext;
> +  UINTN       Addr;
> +  EFI_STATUS  Status;
> +  UINTN       StackIndex;
> +
> +  //
> +  // Get the EBC entry point
> +  //
> +  Addr = EntryPoint;
> +
> +  //
> +  // Now clear out our context
> +  //
> +  ZeroMem ((VOID *) &VmContext, sizeof (VM_CONTEXT));
> +
> +  //
> +  // Save the image handle so we can track the thunks created for this image
> +  //
> +  VmContext.ImageHandle = ImageHandle;
> +  VmContext.SystemTable = SystemTable;
> +
> +  //
> +  // Set the VM instruction pointer to the correct location in memory.
> +  //
> +  VmContext.Ip = (VMIP) Addr;
> +
> +  //
> +  // Initialize the stack pointer for the EBC. Get the current system stack
> +  // pointer and adjust it down by the max needed for the interpreter.
> +  //
> +
> +  Status = GetEBCStack(ImageHandle, &VmContext.StackPool, &StackIndex);
> +  if (EFI_ERROR(Status)) {
> +    return Status;
> +  }
> +  VmContext.StackTop = (UINT8*)VmContext.StackPool + (STACK_REMAIN_SIZE);
> +  VmContext.Gpr[0] = (UINT64) ((UINT8*)VmContext.StackPool + STACK_POOL_SIZE);
> +  VmContext.HighStackBottom = (UINTN) VmContext.Gpr[0];
> +  VmContext.Gpr[0] -= sizeof (UINTN);
> +
> +
> +  //
> +  // Put a magic value in the stack gap, then adjust down again
> +  //
> +  *(UINTN *) (UINTN) (VmContext.Gpr[0]) = (UINTN) VM_STACK_KEY_VALUE;
> +  VmContext.StackMagicPtr             = (UINTN *) (UINTN) VmContext.Gpr[0];
> +
> +  //
> +  // Align the stack on a natural boundary
> +  VmContext.Gpr[0] &= ~(VM_REGISTER)(sizeof(UINTN) - 1);
This code is the same as x64. Is this correct alignment for Aarch64?
> +  //
> +  VmContext.LowStackTop   = (UINTN) VmContext.Gpr[0];
> +
> +  //
> +  // Simply copy the image handle and system table onto the EBC stack.
> +  // Greatly simplifies things by not having to spill the args.
> +  //
> +  PushU64 (&VmContext, (UINT64) SystemTable);
> +  PushU64 (&VmContext, (UINT64) ImageHandle);
> +
> +  //
> +  // VM pushes 16-bytes for return address. Simulate that here.
> +  //
> +  PushU64 (&VmContext, (UINT64) 0);
> +  PushU64 (&VmContext, (UINT64) 0x1234567887654321ULL);
> +
> +  //
> +  // For AArch64, this is where we say our return address is
> +  //
> +  VmContext.StackRetAddr  = (UINT64) VmContext.Gpr[0];
> +
> +  //
> +  // Entry function needn't access high stack context, simply
> +  // put the stack pointer here.
> +  //
> +
> +  //
> +  // Begin executing the EBC code
> +  //
> +  EbcExecute (&VmContext);
> +
> +  //
> +  // Return the value in R[7] unless there was an error
> +  //
> +  ReturnEBCStack(StackIndex);
> +  return (UINT64) VmContext.Gpr[7];
> +}
> +
> +
> +/**
> +  Create thunks for an EBC image entry point, or an EBC protocol service.
> +
> +  @param  ImageHandle           Image handle for the EBC image. If not null, then
> +                                we're creating a thunk for an image entry point.
> +  @param  EbcEntryPoint         Address of the EBC code that the thunk is to call
> +  @param  Thunk                 Returned thunk we create here
> +  @param  Flags                 Flags indicating options for creating the thunk
> +
> +  @retval EFI_SUCCESS           The thunk was created successfully.
> +  @retval EFI_INVALID_PARAMETER The parameter of EbcEntryPoint is not 16-bit
> +                                aligned.
> +  @retval EFI_OUT_OF_RESOURCES  There is not enough memory to created the EBC
> +                                Thunk.
> +  @retval EFI_BUFFER_TOO_SMALL  EBC_THUNK_SIZE is not larger enough.
> +
> +**/
> +EFI_STATUS
> +EbcCreateThunks (
> +  IN EFI_HANDLE           ImageHandle,
> +  IN VOID                 *EbcEntryPoint,
> +  OUT VOID                **Thunk,
> +  IN  UINT32              Flags
> +  )
> +{
> +  UINT8       *Ptr;
> +  UINT8       *ThunkBase;
> +  UINT32      Index;
> +  INT32       ThunkSize;
> +
> +  //
> +  // Check alignment of pointer to EBC code
> +  //
> +  if ((UINT32) (UINTN) EbcEntryPoint & 0x01) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  ThunkSize = sizeof(mInstructionBufferTemplate);
> +
> +  Ptr = AllocatePool (sizeof(mInstructionBufferTemplate));
> +
> +  if (Ptr == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +  //
> +  //  Print(L"Allocate TH: 0x%X\n", (UINT32)Ptr);
> +  //
> +  // Save the start address so we can add a pointer to it to a list later.
> +  //
> +  ThunkBase = Ptr;
> +
> +  //
> +  // Give them the address of our buffer we're going to fix up
> +  //
> +  *Thunk = (VOID *) Ptr;
> +
> +  //
> +  // Copy whole thunk instruction buffer template
> +  //
> +  CopyMem (Ptr, mInstructionBufferTemplate, sizeof(mInstructionBufferTemplate));
> +
> +  //
> +  // Patch EbcEntryPoint and EbcLLEbcInterpret
> +  //
> +  for (Index = 0; Index < sizeof(mInstructionBufferTemplate) - sizeof(UINTN); Index++) {
> +    if (*(UINTN *)&Ptr[Index] == EBC_ENTRYPOINT_SIGNATURE) {
> +      *(UINTN *)&Ptr[Index] = (UINTN)EbcEntryPoint;
> +    }
> +    if (*(UINTN *)&Ptr[Index] == EBC_LL_EBC_ENTRYPOINT_SIGNATURE) {
> +      if ((Flags & FLAG_THUNK_ENTRY_POINT) != 0) {
> +        *(UINTN *)&Ptr[Index] = (UINTN)EbcLLExecuteEbcImageEntryPoint;
> +      } else {
> +        *(UINTN *)&Ptr[Index] = (UINTN)EbcLLEbcInterpret;
> +      }
> +    }
> +  }
> +
> +  //
> +  // Add the thunk to the list for this image. Do this last since the add
> +  // function flushes the cache for us.
> +  //
> +  EbcAddImageThunk (ImageHandle, (VOID *) ThunkBase, ThunkSize);
> +
> +  return EFI_SUCCESS;
> +}
> +
> +
> +/**
> +  This function is called to execute an EBC CALLEX instruction.
> +  The function check the callee's content to see whether it is common native
> +  code or a thunk to another piece of EBC code.
> +  If the callee is common native code, use EbcLLCAllEXASM to manipulate,
> +  otherwise, set the VM->IP to target EBC code directly to avoid another VM
> +  be startup which cost time and stack space.
> +
> +  @param  VmPtr            Pointer to a VM context.
> +  @param  FuncAddr         Callee's address
> +  @param  NewStackPointer  New stack pointer after the call
> +  @param  FramePtr         New frame pointer after the call
> +  @param  Size             The size of call instruction
> +
> +**/
> +VOID
> +EbcLLCALLEX (
> +  IN VM_CONTEXT   *VmPtr,
> +  IN UINTN        FuncAddr,
> +  IN UINTN        NewStackPointer,
> +  IN VOID         *FramePtr,
> +  IN UINT8        Size
> +  )
> +{
> +  UINTN    IsThunk;
> +  UINTN    TargetEbcAddr;
> +  UINT8    InstructionBuffer[sizeof(mInstructionBufferTemplate)];
> +  UINTN    Index;
> +  UINTN    IndexOfEbcEntrypoint;
> +
> +  IsThunk       = 1;
> +  TargetEbcAddr = 0;
> +  IndexOfEbcEntrypoint = 0;
> +
> +  //
> +  // Processor specific code to check whether the callee is a thunk to EBC.
> +  //
> +  CopyMem (InstructionBuffer, (VOID *)FuncAddr, sizeof(InstructionBuffer));
> +  //
> +  // Fill the signature according to mInstructionBufferTemplate
> +  //
> +  for (Index = 0; Index < sizeof(mInstructionBufferTemplate) - sizeof(UINTN); Index++) {
> +    if (*(UINTN *)&mInstructionBufferTemplate[Index] == EBC_ENTRYPOINT_SIGNATURE) {
> +      *(UINTN *)&InstructionBuffer[Index] = EBC_ENTRYPOINT_SIGNATURE;
> +      IndexOfEbcEntrypoint = Index;
> +    }
> +    if (*(UINTN *)&mInstructionBufferTemplate[Index] == EBC_LL_EBC_ENTRYPOINT_SIGNATURE) {
> +      *(UINTN *)&InstructionBuffer[Index] = EBC_LL_EBC_ENTRYPOINT_SIGNATURE;
> +    }
> +  }
> +  //
> +  // Check if we need thunk to native
> +  //
> +  if (CompareMem (InstructionBuffer, mInstructionBufferTemplate, sizeof(mInstructionBufferTemplate)) != 0) {
> +    IsThunk = 0;
> +  }
> +
> +  if (IsThunk == 1){
> +    //
> +    // The callee is a thunk to EBC, adjust the stack pointer down 16 bytes and
> +    // put our return address and frame pointer on the VM stack.
> +    // Then set the VM's IP to new EBC code.
> +    //
> +    VmPtr->Gpr[0] -= 8;
> +    VmWriteMemN (VmPtr, (UINTN) VmPtr->Gpr[0], (UINTN) FramePtr);
> +    VmPtr->FramePtr = (VOID *) (UINTN) VmPtr->Gpr[0];
> +    VmPtr->Gpr[0] -= 8;
> +    VmWriteMem64 (VmPtr, (UINTN) VmPtr->Gpr[0], (UINT64) (UINTN) (VmPtr->Ip + Size));
> +
> +    CopyMem (&TargetEbcAddr, (UINT8 *)FuncAddr + IndexOfEbcEntrypoint, sizeof(UINTN));
> +    VmPtr->Ip = (VMIP) (UINTN) TargetEbcAddr;
> +  } else {
> +    //
> +    // The callee is not a thunk to EBC, call native code,
> +    // and get return value.
> +    //
> +    VmPtr->Gpr[7] = EbcLLCALLEXNative (FuncAddr, NewStackPointer, FramePtr);
> +
> +    //
> +    // Advance the IP.
> +    //
> +    VmPtr->Ip += Size;
> +  }
> +}
> +
> diff --git a/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf b/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
> index 15dc01c..e9a0b28 100644
> --- a/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
> +++ b/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
> @@ -5,6 +5,7 @@
>   #  platform and processor-independent mechanisms for loading and executing EFI
>   #  device drivers.
>   #
> +#  Copyright (c) 2015, The Linux Foundation. All rights reserved.
>   #  Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
>   #  This program and the accompanying materials
>   #  are licensed and made available under the terms and conditions of the BSD License
> @@ -28,7 +29,7 @@ [Defines]
>   #
>   # The following information is for reference only and not required by the build tools.
>   #
> -#  VALID_ARCHITECTURES           = IA32 X64 IPF
> +#  VALID_ARCHITECTURES           = IA32 X64 IPF AARCH64
>   #
>   
>   [Sources]
> @@ -54,6 +55,9 @@ [Sources.IPF]
>     Ipf/EbcSupport.c
>     Ipf/EbcLowLevel.s
>   
> +[Sources.AARCH64]
> +  AArch64/EbcSupport.c
> +  AArch64/EbcLowLevel.S
>   
>   [Packages]
>     MdePkg/MdePkg.dec

Thanks,
Daniil