EdkCompatibilityPkg/Compatibility/BootScriptSaveOnS3SaveStateThunk/X64/DispatchExecute.c

   1 /** @file
   2   Execute 32-bit code in Long Mode
   3   Provide a thunk function to transition from long mode to compatibility mode to execute 32-bit code and then transit
   4   back to long mode.
   5
   6   Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>
   7   This program and the accompanying materials
   8   are licensed and made available under the terms and conditions of the BSD License
   9   which accompanies this distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16 #include "ScriptSave.h"
  17
  18 #pragma pack(1)
  19 typedef union {
  20   struct {
  21     UINT32  LimitLow    : 16;
  22     UINT32  BaseLow     : 16;
  23     UINT32  BaseMid     : 8;
  24     UINT32  Type        : 4;
  25     UINT32  System      : 1;
  26     UINT32  Dpl         : 2;
  27     UINT32  Present     : 1;
  28     UINT32  LimitHigh   : 4;
  29     UINT32  Software    : 1;
  30     UINT32  Reserved    : 1;
  31     UINT32  DefaultSize : 1;
  32     UINT32  Granularity : 1;
  33     UINT32  BaseHigh    : 8;
  34   } Bits;
  35   UINT64  Uint64;
  36 } IA32_GDT;
  37 #pragma pack()
  38
  39 //
  40 // Global Descriptor Table (GDT)
  41 //
  42 GLOBAL_REMOVE_IF_UNREFERENCED IA32_GDT mGdtEntries[] = {
  43   {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, /* 0x0:  reserve */
  44   {{0xFFFF, 0,  0,  0xB,  1,  0,  1,  0xF,  0,  0, 1,  1,  0}}, /* 0x8:  compatibility mode */
  45   {{0xFFFF, 0,  0,  0xB,  1,  0,  1,  0xF,  0,  1, 0,  1,  0}}, /* 0x10: for long mode */
  46   {{0xFFFF, 0,  0,  0x3,  1,  0,  1,  0xF,  0,  0, 1,  1,  0}}, /* 0x18: data */
  47   {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, /* 0x20: reserve */
  48 };
  49
  50 //
  51 // IA32 Gdt register
  52 //
  53 GLOBAL_REMOVE_IF_UNREFERENCED IA32_DESCRIPTOR mGdt = {
  54   sizeof (mGdtEntries) - 1,
  55   (UINTN) mGdtEntries
  56   };
  57 /**
  58   Assembly function to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
  59   long mode.
  60   @param  Function     The 32bit code entry to be executed.
  61   @param  Param1       The first parameter to pass to 32bit code
  62   @param  Param2       The second parameter to pass to 32bit code
  63   @param  InternalGdtr The GDT and GDT descriptor used by this library
  64
  65   @retval EFI_SUCCESS  Execute 32bit code successfully.
  66   @retval other        Something wrong when execute the 32bit code
  67 **/
  68 EFI_STATUS
  69 AsmExecute32BitCode (
  70   IN UINT64           Function,
  71   IN UINT64           Param1,
  72   IN UINT64           Param2,
  73   IN IA32_DESCRIPTOR  *InternalGdtr
  74   );
  75
  76 /**
  77   Wrapper for a thunk  to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
  78   long mode.
  79
  80   @param  Function     The 32bit code entry to be executed.
  81   @param  Param1       The first parameter to pass to 32bit code
  82   @param  Param2       The second parameter to pass to 32bit code
  83   @retval EFI_SUCCESS  Execute 32bit code successfully.
  84   @retval other        Something wrong when execute the 32bit code
  85
  86 **/
  87 EFI_STATUS
  88 Execute32BitCode (
  89   IN UINT64      Function,
  90   IN UINT64      Param1,
  91   IN UINT64      Param2
  92   )
  93 {
  94   EFI_STATUS                 Status;
  95
  96   ASSERT (Function != 0);
  97
  98   Status = AsmExecute32BitCode (
  99              Function,
 100              Param1,
 101              Param2,
 102              &mGdt
 103              );
 104   return Status;
 105 }
 106