EdkModulePkg/Universal/Ebc/Dxe/x64/EbcLowLevel.S

   1 #****************************************************************************
   2 #*
   3 #*  Copyright (c) 2006, Intel Corporation
   4 #*  All rights reserved. This program and the accompanying materials
   5 #*  are licensed and made available under the terms and conditions of the BSD License
   6 #*  which accompanies this distribution.  The full text of the license may be found at
   7 #*  http://opensource.org/licenses/bsd-license.php
   8 #*
   9 #*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 #*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #*
  12 #****************************************************************************
  13 #****************************************************************************
  14 #                                   REV 1.0
  15 #****************************************************************************
  16 #
  17 # Rev  Date      Description
  18 # ---  --------  ------------------------------------------------------------
  19 # 1.0  05/09/12  Initial creation of file.
  20 #
  21 #****************************************************************************
  22
  23 #* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  24 # This code provides low level routines that support the Virtual Machine
  25 # for option ROMs.
  26 #* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  27
  28 #---------------------------------------------------------------------------
  29 # Equate files needed.
  30 #---------------------------------------------------------------------------
  31
  32 #---------------------------------------------------------------------------
  33 ##GenericPostSegment      SEGMENT USE16
  34 #---------------------------------------------------------------------------
  35
  36 #****************************************************************************
  37 # EbcLLCALLEX
  38 #
  39 # This function is called to execute an EBC CALLEX instruction.
  40 # This instruction requires that we thunk out to external native
  41 # code. For x64, we switch stacks, copy the arguments to the stack
  42 # and jump to the specified function.
  43 # On return, we restore the stack pointer to its original location.
  44 #
  45 # Destroys no working registers.
  46 #****************************************************************************
  47 .global _CopyMem;
  48
  49 # VOID EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)
  50 .global _EbcLLCALLEXNative;
  51 _EbcLLCALLEXNative:
  52       push   %rbp
  53       push   %rbx
  54       mov    %rsp, %rbp
  55       # Function prolog
  56
  57       # Copy FuncAddr to a preserved register.
  58       mov    %rcx, %rbx
  59
  60       # Set stack pointer to new value
  61       sub    %r8,  %rdx
  62       sub    %rsp, %r8
  63       mov    %rsp, %rcx
  64       sub    %rsp, 0x20
  65       call   _CopyMem
  66       add    %rsp, 0x20
  67
  68       # Considering the worst case, load 4 potiential arguments
  69       # into registers.
  70       mov    (%rsp), %rcx
  71       mov    8(%rsp), %rdx
  72       mov    10(%rsp), %r8
  73       mov    18(%rsp), %r9
  74
  75       # Now call the external routine
  76       call  *%rbx
  77
  78       # Function epilog
  79       mov      %rbp, %rsp
  80       pop      %rbx
  81       pop      %rbp
  82       ret
  83
  84
  85 # UINTN EbcLLGetEbcEntryPoint(VOID);
  86 # Routine Description:
  87 #   The VM thunk code stuffs an EBC entry point into a processor
  88 #   register. Since we can't use inline assembly to get it from
  89 #   the interpreter C code, stuff it into the return value
  90 #   register and return.
  91 #
  92 # Arguments:
  93 #     None.
  94 #
  95 # Returns:
  96 #     The contents of the register in which the entry point is passed.
  97 #
  98 .global _EbcLLGetEbcEntryPoint;
  99 _EbcLLGetEbcEntryPoint:
 100     ret
 101
 102 #/*++
 103 #
 104 #Routine Description:
 105 #
 106 #  Return the caller's value of the stack pointer.
 107 #
 108 #Arguments:
 109 #
 110 #  None.
 111 #
 112 #Returns:
 113 #
 114 #  The current value of the stack pointer for the caller. We
 115 #  adjust it by 4 here because when they called us, the return address
 116 #  is put on the stack, thereby lowering it by 4 bytes.
 117 #
 118 #--*/
 119
 120 # UINTN EbcLLGetStackPointer()
 121 .global _EbcLLGetStackPointer;
 122 _EbcLLGetStackPointer:
 123     mov    %rsp, %rax
 124     # Stack adjusted by this much when we were called,
 125     # For this function, it's 4.
 126     add   $4, %rax
 127     ret
 128
 129 .global _EbcLLGetReturnValue;
 130 _EbcLLGetReturnValue:
 131 # UINT64 EbcLLGetReturnValue(VOID);
 132 # Routine Description:
 133 #   When EBC calls native, on return the VM has to stuff the return
 134 #   value into a VM register. It's assumed here that the value is still
 135 #    in the register, so simply return and the caller should get the
 136 #   return result properly.
 137 #
 138 # Arguments:
 139 #     None.
 140 #
 141 # Returns:
 142 #     The unmodified value returned by the native code.
 143 #
 144     ret