Remove assumption on EAX and R10 usage for IA32 compiler and X64 compiler.

Signed-off-by: jyao1
Reviewed-by: lgao4

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12760 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/EbcDxe/Ia32/EbcLowLevel.S

@@ -14,6 +14,8 @@
 #**/
 
 ASM_GLOBAL ASM_PFX(CopyMem)
+ASM_GLOBAL ASM_PFX(EbcInterpret)
+ASM_GLOBAL ASM_PFX(ExecuteEbcImageEntryPoint)
 
 ASM_GLOBAL ASM_PFX(EbcLLCALLEXNative)
 ASM_PFX(EbcLLCALLEXNative):
@@ -42,6 +44,40 @@ ASM_PFX(EbcLLCALLEXNative):
          pop    %ebp
          ret
 
-ASM_GLOBAL ASM_PFX(EbcLLGetEbcEntryPoint)
+ASM_GLOBAL ASM_PFX(EbcLLEbcInterpret)
-ASM_PFX(EbcLLGetEbcEntryPoint):
+ASM_PFX(EbcLLEbcInterpret):
-        ret
+    # Construct new stack
+    push %ebp
+    mov  %esp, %ebp
+    push %esi
+    push %edi
+    sub  $0x40, %esp
+    push %eax
+    mov  %ebp, %esi
+    add  $0x8, %esi
+    mov  %esp, %edi
+    add  $0x4, %edi
+    mov  $0x10, %ecx
+    rep  movsd
+    
+    # call C-code
+    call ASM_PFX(EbcInterpret)
+    add  $0x44, %esp
+    pop  %edi
+    pop  %esi
+    pop  %ebp
+    ret
+
+ASM_GLOBAL ASM_PFX(EbcLLExecuteEbcImageEntryPoint)
+ASM_PFX(EbcLLExecuteEbcImageEntryPoint):
+    # Construct new stack
+    mov  %eax, -0xC(%esp)
+    mov  0x4(%esp), %eax
+    mov  %eax, -0x8(%esp)
+    mov  0x8(%esp), %eax
+    mov  %eax, -0x4(%esp)
+    # call C-code
+    sub  $0xC, %esp
+    call ASM_PFX(ExecuteEbcImageEntryPoint)
+    add  $0xC, %esp
+    ret

MdeModulePkg/Universal/EbcDxe/Ia32/EbcLowLevel.asm

@@ -30,9 +30,11 @@
 ;---------------------------------------------------------------------------
 
 .686p
-.model  flat
+.model  flat, C
 .code
-CopyMem  PROTO  C Destination:PTR DWORD, Source:PTR DWORD, Count:DWORD
+CopyMem  PROTO  Destination:PTR DWORD, Source:PTR DWORD, Count:DWORD
+EbcInterpret               PROTO
+ExecuteEbcImageEntryPoint  PROTO
 
 ;****************************************************************************
 ; EbcLLCALLEXNative
@@ -47,7 +49,7 @@ CopyMem  PROTO  C Destination:PTR DWORD, Source:PTR DWORD, Count:DWORD
 ; Destroys no working registers.
 ;****************************************************************************
 ; INT64 EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)
-_EbcLLCALLEXNative        PROC        PUBLIC
+EbcLLCALLEXNative        PROC        PUBLIC
       push   ebp
       push   ebx
       mov    ebp, esp              ; standard function prolog
@@ -85,25 +87,121 @@ _EbcLLCALLEXNative        PROC        PUBLIC
       pop      ebx
       pop      ebp
       ret
-_EbcLLCALLEXNative    ENDP
+EbcLLCALLEXNative    ENDP
 
+;****************************************************************************
+; EbcLLEbcInterpret
+;
+; Begin executing an EBC image.
+;****************************************************************************
+; UINT64 EbcLLEbcInterpret(VOID)
+EbcLLEbcInterpret PROC PUBLIC
+    ;
+    ;; mov eax, 0xca112ebc
+    ;; mov eax, EbcEntryPoint
+    ;; mov ecx, EbcLLEbcInterpret
+    ;; jmp ecx
+    ;
+    ; Caller uses above instruction to jump here
+    ; The stack is below:
+    ; +-----------+
+    ; |  RetAddr  |
+    ; +-----------+
+    ; |EntryPoint | (EAX)
+    ; +-----------+
+    ; |   Arg1    | <- EDI
+    ; +-----------+
+    ; |   Arg2    |
+    ; +-----------+
+    ; |   ...     |
+    ; +-----------+
+    ; |   Arg16   |
+    ; +-----------+
+    ; |   EDI     |
+    ; +-----------+
+    ; |   ESI     |
+    ; +-----------+
+    ; |   EBP     | <- EBP
+    ; +-----------+
+    ; |  RetAddr  | <- ESP is here
+    ; +-----------+
+    ; |   Arg1    | <- ESI
+    ; +-----------+
+    ; |   Arg2    |
+    ; +-----------+
+    ; |   ...     |
+    ; +-----------+
+    ; |   Arg16   |
+    ; +-----------+
+    ; 
 
-; UINTN EbcLLGetEbcEntryPoint(VOID);
+    ; Construct new stack
-; Routine Description:
+    push ebp
-;   The VM thunk code stuffs an EBC entry point into a processor
+    mov  ebp, esp
-;   register. Since we can't use inline assembly to get it from
+    push esi
-;   the interpreter C code, stuff it into the return value
+    push edi
-;   register and return.
+    sub  esp, 40h
-;
+    push eax
-; Arguments:
+    mov  esi, ebp
-;     None.
+    add  esi, 8
-;
+    mov  edi, esp
-; Returns:
+    add  edi, 4
-;     The contents of the register in which the entry point is passed.
+    mov  ecx, 16
-;
+    rep  movsd
-_EbcLLGetEbcEntryPoint        PROC        PUBLIC
+    
-    ; The EbcEntryPoint is saved to EAX, so just return here.
+    ; call C-code
+    call EbcInterpret
+    add  esp, 44h
+    pop  edi
+    pop  esi
+    pop  ebp
     ret
-_EbcLLGetEbcEntryPoint    ENDP
+EbcLLEbcInterpret ENDP
+
+;****************************************************************************
+; EbcLLExecuteEbcImageEntryPoint
+;
+; Begin executing an EBC image.
+;****************************************************************************
+; UINT64 EbcLLExecuteEbcImageEntryPoint(VOID)
+EbcLLExecuteEbcImageEntryPoint PROC PUBLIC
+    ;
+    ;; mov eax, 0xca112ebc
+    ;; mov eax, EbcEntryPoint
+    ;; mov ecx, EbcLLExecuteEbcImageEntryPoint
+    ;; jmp ecx
+    ;
+    ; Caller uses above instruction to jump here
+    ; The stack is below:
+    ; +-----------+
+    ; |  RetAddr  |
+    ; +-----------+
+    ; |EntryPoint | (EAX)
+    ; +-----------+
+    ; |ImageHandle|
+    ; +-----------+
+    ; |SystemTable|
+    ; +-----------+
+    ; |  RetAddr  | <- ESP is here
+    ; +-----------+
+    ; |ImageHandle|
+    ; +-----------+
+    ; |SystemTable|
+    ; +-----------+
+    ; 
+    
+    ; Construct new stack
+    mov  [esp - 0Ch], eax
+    mov  eax, [esp + 04h]
+    mov  [esp - 08h], eax
+    mov  eax, [esp + 08h]
+    mov  [esp - 04h], eax
+    
+    ; call C-code
+    sub  esp, 0Ch
+    call ExecuteEbcImageEntryPoint
+    add  esp, 0Ch
+    ret
+EbcLLExecuteEbcImageEntryPoint ENDP
 
 END

MdeModulePkg/Universal/EbcDxe/Ia32/EbcSupport.c

@@ -27,6 +27,31 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 #define STACK_REMAIN_SIZE (1024 * 4)
 
+/**
+  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
+  );
 
 /**
   This function is called to execute an EBC CALLEX instruction.
@@ -131,14 +156,13 @@ Action:
 
 
 /**
-  Begin executing an EBC image. The address of the entry point is passed
+  Begin executing an EBC image.
-  in via a processor register, so we'll need to make a call to get the
-  value.
 
   This is a thunk function. Microsoft x64 compiler only provide fast_call
   calling convention, so the first four arguments are passed by rcx, rdx,
   r8, and r9, while other arguments are passed in stack.
 
+  @param  EntryPoint            The entrypoint of EBC code.
   @param  Arg1                  The 1st argument.
   @param  Arg2                  The 2nd argument.
   @param  Arg3                  The 3rd argument.
@@ -162,22 +186,23 @@ Action:
 UINT64
 EFIAPI
 EbcInterpret (
-  IN OUT UINTN      Arg1,
+  IN UINTN      EntryPoint,
-  IN OUT UINTN      Arg2,
+  IN UINTN      Arg1,
-  IN OUT UINTN      Arg3,
+  IN UINTN      Arg2,
-  IN OUT UINTN      Arg4,
+  IN UINTN      Arg3,
-  IN OUT UINTN      Arg5,
+  IN UINTN      Arg4,
-  IN OUT UINTN      Arg6,
+  IN UINTN      Arg5,
-  IN OUT UINTN      Arg7,
+  IN UINTN      Arg6,
-  IN OUT UINTN      Arg8,
+  IN UINTN      Arg7,
-  IN OUT UINTN      Arg9,
+  IN UINTN      Arg8,
-  IN OUT UINTN      Arg10,
+  IN UINTN      Arg9,
-  IN OUT UINTN      Arg11,
+  IN UINTN      Arg10,
-  IN OUT UINTN      Arg12,
+  IN UINTN      Arg11,
-  IN OUT UINTN      Arg13,
+  IN UINTN      Arg12,
-  IN OUT UINTN      Arg14,
+  IN UINTN      Arg13,
-  IN OUT UINTN      Arg15,
+  IN UINTN      Arg14,
-  IN OUT UINTN      Arg16
+  IN UINTN      Arg15,
+  IN UINTN      Arg16
   )
 {
   //
@@ -189,9 +214,9 @@ EbcInterpret (
   UINTN       StackIndex;
 
   //
-  // Get the EBC entry point from the processor register.
+  // Get the EBC entry point
   //
-  Addr = EbcLLGetEbcEntryPoint ();
+  Addr = EntryPoint;
 
   //
   // Now clear out our context
@@ -297,10 +322,9 @@ EbcInterpret (
 
 
 /**
-  Begin executing an EBC image. The address of the entry point is passed
+  Begin executing an EBC image.
-  in via a processor register, so we'll need to make a call to get the
-  value.
 
+  @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
@@ -311,6 +335,7 @@ EbcInterpret (
 UINT64
 EFIAPI
 ExecuteEbcImageEntryPoint (
+  IN UINTN                EntryPoint,
   IN EFI_HANDLE           ImageHandle,
   IN EFI_SYSTEM_TABLE     *SystemTable
   )
@@ -324,15 +349,10 @@ ExecuteEbcImageEntryPoint (
   UINTN       StackIndex;
 
   //
-  // Get the EBC entry point from the processor register. Make sure you don't
+  // Get the EBC entry point
-  // call any functions before this or you could mess up the register the
-  // entry point is passed in.
   //
-  Addr = EbcLLGetEbcEntryPoint ();
+  Addr = EntryPoint;
 
-  //
-  //  Print(L"*** Thunked into EBC entry point - ImageHandle = 0x%X\n", (UINTN)ImageHandle);
-  //  Print(L"EBC entry point is 0x%X\n", (UINT32)(UINTN)Addr);
   //
   // Now clear out our context
   //
@@ -496,9 +516,9 @@ EbcCreateThunks (
   //  mov ecx 12345678h  => 0xB9 0x78 0x56 0x34 0x12
   //
   if ((Flags & FLAG_THUNK_ENTRY_POINT) != 0) {
-    Addr = (UINT32) (UINTN) ExecuteEbcImageEntryPoint;
+    Addr = (UINT32) (UINTN) EbcLLExecuteEbcImageEntryPoint;
   } else {
-    Addr = (UINT32) (UINTN) EbcInterpret;
+    Addr = (UINT32) (UINTN) EbcLLEbcInterpret;
   }
 
   //

MdeModulePkg/Universal/EbcDxe/X64/EbcLowLevel.S

@@ -19,6 +19,8 @@
 #---------------------------------------------------------------------------
 
 ASM_GLOBAL ASM_PFX(CopyMem);
+ASM_GLOBAL ASM_PFX(EbcInterpret);
+ASM_GLOBAL ASM_PFX(ExecuteEbcImageEntryPoint);
 
 #****************************************************************************
 # EbcLLCALLEX
@@ -66,21 +68,53 @@ ASM_PFX(EbcLLCALLEXNative):
       pop      %rbp
       ret
 
+ASM_GLOBAL ASM_PFX(EbcLLEbcInterpret);
+ASM_PFX(EbcLLEbcInterpret):
+    # save old parameter to stack
+    mov  %rcx, 0x8(%rsp)
+    mov  %rdx, 0x10(%rsp)
+    mov  %r8, 0x18(%rsp)
+    mov  %r9, 0x20(%rsp)
 
-# UINTN EbcLLGetEbcEntryPoint(VOID);
+    # Construct new stack
-# Routine Description:
+    push %rbp
-#   The VM thunk code stuffs an EBC entry point into a processor
+    mov  %rsp, %rbp
-#   register. Since we can't use inline assembly to get it from
+    push %rsi
-#   the interpreter C code, stuff it into the return value
+    push %rdi
-#   register and return.
+    push %rbx
-#
+    sub  $0x80, %rsp
-# Arguments:
+    push %r10
-#     None.
+    mov  %rbp, %rsi
-#
+    add  $0x10, %rsi
-# Returns:
+    mov  %rsp, %rdi
-#     The contents of the register in which the entry point is passed.
+    add  $0x8, %rdi
-#
+    mov  $0x10, %rcx
-ASM_GLOBAL ASM_PFX(EbcLLGetEbcEntryPoint);
+    rep  movsq
-ASM_PFX(EbcLLGetEbcEntryPoint):
+    
-    mov    %r10, %rax
+    # build new paramater calling convention
+    mov  0x18(%rsp), %r9
+    mov  0x10(%rsp), %r8
+    mov  0x8(%rsp), %rdx
+    mov  %r10, %rcx
+
+    # call C-code
+    call ASM_PFX(EbcInterpret)
+    add  $0x88, %esp
+    pop  %rbx
+    pop  %rdi
+    pop  %rsi
+    pop  %rbp
+    ret
+
+ASM_GLOBAL ASM_PFX(EbcLLExecuteEbcImageEntryPoint);
+ASM_PFX(EbcLLExecuteEbcImageEntryPoint):
+    # build new paramater calling convention
+    mov  %rdx, %r8
+    mov  %rcx, %rdx
+    mov  %r10, %rcx
+
+    # call C-code
+    sub  $0x28, %rsp
+    call ASM_PFX(ExecuteEbcImageEntryPoint)
+    add  $0x28, %rsp
     ret

MdeModulePkg/Universal/EbcDxe/X64/EbcLowLevel.asm

@@ -24,6 +24,8 @@
 .CODE
 
 CopyMem  PROTO  Destination:PTR DWORD, Source:PTR DWORD, Count:DWORD
+EbcInterpret               PROTO
+ExecuteEbcImageEntryPoint  PROTO
 
 ;****************************************************************************
 ; EbcLLCALLEX
@@ -71,25 +73,146 @@ EbcLLCALLEXNative        PROC    PUBLIC
       ret
 EbcLLCALLEXNative    ENDP
 
+;****************************************************************************
+; EbcLLEbcInterpret
+;
+; Begin executing an EBC image.
+;****************************************************************************
+; UINT64 EbcLLEbcInterpret(VOID)
+EbcLLEbcInterpret PROC PUBLIC
+    ;
+    ;; mov rax, ca112ebccall2ebch
+    ;; mov r10, EbcEntryPoint
+    ;; mov r11, EbcLLEbcInterpret
+    ;; jmp r11
+    ;
+    ; Caller uses above instruction to jump here
+    ; The stack is below:
+    ; +-----------+
+    ; |  RetAddr  |
+    ; +-----------+
+    ; |EntryPoint | (R10)
+    ; +-----------+
+    ; |   Arg1    | <- RDI
+    ; +-----------+
+    ; |   Arg2    |
+    ; +-----------+
+    ; |   ...     |
+    ; +-----------+
+    ; |   Arg16   |
+    ; +-----------+
+    ; |   Dummy   |
+    ; +-----------+
+    ; |   RDI     |
+    ; +-----------+
+    ; |   RSI     |
+    ; +-----------+
+    ; |   RBP     | <- RBP
+    ; +-----------+
+    ; |  RetAddr  | <- RSP is here
+    ; +-----------+
+    ; |  Scratch1 | (RCX) <- RSI
+    ; +-----------+
+    ; |  Scratch2 | (RDX)
+    ; +-----------+
+    ; |  Scratch3 | (R8)
+    ; +-----------+
+    ; |  Scratch4 | (R9)
+    ; +-----------+
+    ; |   Arg5    |
+    ; +-----------+
+    ; |   Arg6    |
+    ; +-----------+
+    ; |   ...     |
+    ; +-----------+
+    ; |   Arg16   |
+    ; +-----------+
+    ;
 
-; UINTN EbcLLGetEbcEntryPoint(VOID);
+    ; save old parameter to stack
-; Routine Description:
+    mov  [rsp + 08h], rcx
-;   The VM thunk code stuffs an EBC entry point into a processor
+    mov  [rsp + 10h], rdx
-;   register. Since we can't use inline assembly to get it from
+    mov  [rsp + 18h], r8
-;   the interpreter C code, stuff it into the return value
+    mov  [rsp + 20h], r9
-;   register and return.
+
-;
+    ; Construct new stack
-; Arguments:
+    push rbp
-;     None.
+    mov  rbp, rsp
-;
+    push rsi
-; Returns:
+    push rdi
-;     The contents of the register in which the entry point is passed.
+    push rbx
-;
+    sub  rsp, 80h
-EbcLLGetEbcEntryPoint        PROC    PUBLIC
+    push r10
-    ; The EbcEntryPoint is saved to R10.
+    mov  rsi, rbp
-    mov  rax, r10
+    add  rsi, 10h
+    mov  rdi, rsp
+    add  rdi, 8
+    mov  rcx, 16
+    rep  movsq
+    
+    ; build new paramater calling convention
+    mov  r9,  [rsp + 18h]
+    mov  r8,  [rsp + 10h]
+    mov  rdx, [rsp + 08h]
+    mov  rcx, r10
+
+    ; call C-code
+    call EbcInterpret
+    add  rsp, 88h
+    pop  rbx
+    pop  rdi
+    pop  rsi
+    pop  rbp
     ret
-EbcLLGetEbcEntryPoint    ENDP
+EbcLLEbcInterpret ENDP
+
+;****************************************************************************
+; EbcLLExecuteEbcImageEntryPoint
+;
+; Begin executing an EBC image.
+;****************************************************************************
+; UINT64 EbcLLExecuteEbcImageEntryPoint(VOID)
+EbcLLExecuteEbcImageEntryPoint PROC PUBLIC
+    ;
+    ;; mov rax, ca112ebccall2ebch
+    ;; mov r10, EbcEntryPoint
+    ;; mov r11, EbcLLExecuteEbcImageEntryPoint
+    ;; jmp r11
+    ;
+    ; Caller uses above instruction to jump here
+    ; The stack is below:
+    ; +-----------+
+    ; |  RetAddr  |
+    ; +-----------+
+    ; |EntryPoint | (R10)
+    ; +-----------+
+    ; |ImageHandle|
+    ; +-----------+
+    ; |SystemTable|
+    ; +-----------+
+    ; |   Dummy   |
+    ; +-----------+
+    ; |   Dummy   |
+    ; +-----------+
+    ; |  RetAddr  | <- RSP is here
+    ; +-----------+
+    ; |ImageHandle| (RCX)
+    ; +-----------+
+    ; |SystemTable| (RDX)
+    ; +-----------+
+    ; 
+
+    ; build new paramater calling convention
+    mov  r8, rdx
+    mov  rdx, rcx
+    mov  rcx, r10
+
+    ; call C-code
+    sub  rsp, 28h
+    call ExecuteEbcImageEntryPoint
+    add  rsp, 28h
+    ret
+EbcLLExecuteEbcImageEntryPoint ENDP
 
 END
 

MdeModulePkg/Universal/EbcDxe/X64/EbcSupport.c

@@ -27,6 +27,31 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 #define STACK_REMAIN_SIZE (1024 * 4)
 
+/**
+  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.
@@ -52,14 +77,13 @@ PushU64 (
 
 
 /**
-  Begin executing an EBC image. The address of the entry point is passed
+  Begin executing an EBC image.
-  in via a processor register, so we'll need to make a call to get the
-  value.
 
   This is a thunk function. Microsoft x64 compiler only provide fast_call
   calling convention, so the first four arguments are passed by rcx, rdx,
   r8, and r9, while other arguments are passed in stack.
 
+  @param  EntryPoint            The entrypoint of EBC code.
   @param  Arg1                  The 1st argument.
   @param  Arg2                  The 2nd argument.
   @param  Arg3                  The 3rd argument.
@@ -83,22 +107,23 @@ PushU64 (
 UINT64
 EFIAPI
 EbcInterpret (
-  IN OUT UINTN      Arg1,
+  IN UINTN      EntryPoint,
-  IN OUT UINTN      Arg2,
+  IN UINTN      Arg1,
-  IN OUT UINTN      Arg3,
+  IN UINTN      Arg2,
-  IN OUT UINTN      Arg4,
+  IN UINTN      Arg3,
-  IN OUT UINTN      Arg5,
+  IN UINTN      Arg4,
-  IN OUT UINTN      Arg6,
+  IN UINTN      Arg5,
-  IN OUT UINTN      Arg7,
+  IN UINTN      Arg6,
-  IN OUT UINTN      Arg8,
+  IN UINTN      Arg7,
-  IN OUT UINTN      Arg9,
+  IN UINTN      Arg8,
-  IN OUT UINTN      Arg10,
+  IN UINTN      Arg9,
-  IN OUT UINTN      Arg11,
+  IN UINTN      Arg10,
-  IN OUT UINTN      Arg12,
+  IN UINTN      Arg11,
-  IN OUT UINTN      Arg13,
+  IN UINTN      Arg12,
-  IN OUT UINTN      Arg14,
+  IN UINTN      Arg13,
-  IN OUT UINTN      Arg15,
+  IN UINTN      Arg14,
-  IN OUT UINTN      Arg16
+  IN UINTN      Arg15,
+  IN UINTN      Arg16
   )
 {
   //
@@ -110,11 +135,9 @@ EbcInterpret (
   UINTN       StackIndex;
 
   //
-  // Get the EBC entry point from the processor register.
+  // Get the EBC entry point
-  // Don't call any function before getting the EBC entry
-  // point because this will collab the return register.
   //
-  Addr = EbcLLGetEbcEntryPoint ();
+  Addr = EntryPoint;
 
   //
   // Now clear out our context
@@ -221,10 +244,9 @@ EbcInterpret (
 
 
 /**
-  Begin executing an EBC image. The address of the entry point is passed
+  Begin executing an EBC image.
-  in via a processor register, so we'll need to make a call to get the
-  value.
 
+  @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
@@ -235,6 +257,7 @@ EbcInterpret (
 UINT64
 EFIAPI
 ExecuteEbcImageEntryPoint (
+  IN UINTN                EntryPoint,
   IN EFI_HANDLE           ImageHandle,
   IN EFI_SYSTEM_TABLE     *SystemTable
   )
@@ -248,11 +271,9 @@ ExecuteEbcImageEntryPoint (
   UINTN       StackIndex;
 
   //
-  // Get the EBC entry point from the processor register. Make sure you don't
+  // Get the EBC entry point
-  // call any functions before this or you could mess up the register the
-  // entry point is passed in.
   //
-  Addr = EbcLLGetEbcEntryPoint ();
+  Addr = EntryPoint;
 
   //
   // Now clear out our context
@@ -437,9 +458,9 @@ EbcCreateThunks (
   // mov r11 123456789abcdef0h  => 49 BB F0 DE BC 9A 78 56 34 12
   //
   if ((Flags & FLAG_THUNK_ENTRY_POINT) != 0) {
-    Addr = (UINTN) ExecuteEbcImageEntryPoint;
+    Addr = (UINTN) EbcLLExecuteEbcImageEntryPoint;
   } else {
-    Addr = (UINTN) EbcInterpret;
+    Addr = (UINTN) EbcLLEbcInterpret;
   }
 
   //