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

[Leif Lindholm <leif.lindholm@linaro.org>]

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)
+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
+//
+#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
+
+};
+
+/**
+  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);
+
+  //
+  // 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);
+  //
+  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
-- 
2.1.4