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 - 2012, 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
  38 ///
  39 /// Byte packed structure for an IA-32 Interrupt Gate Descriptor.
  40 ///
  41 typedef union {
  42   struct {
  43     UINT32  OffsetLow:16;   ///< Offset bits 15..0.
  44     UINT32  Selector:16;    ///< Selector.
  45     UINT32  Reserved_0:8;   ///< Reserved.
  46     UINT32  GateType:8;     ///< Gate Type.  See #defines above.
  47     UINT32  OffsetHigh:16;  ///< Offset bits 31..16.
  48   } Bits;
  49   UINT64  Uint64;
  50 } IA32_IDT_ENTRY;
  51 #pragma pack()
  52
  53 #define COMPATIBILITY_MODE_SELECTOR  8
  54
  55 //
  56 // Global Descriptor Table (GDT)
  57 //
  58 GLOBAL_REMOVE_IF_UNREFERENCED IA32_GDT mGdtEntries[] = {
  59   {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, /* 0x0:  reserve */
  60   {{0xFFFF, 0,  0,  0xB,  1,  0,  1,  0xF,  0,  0, 1,  1,  0}}, /* 0x8:  compatibility mode */
  61   {{0xFFFF, 0,  0,  0xB,  1,  0,  1,  0xF,  0,  1, 0,  1,  0}}, /* 0x10: for long mode */
  62   {{0xFFFF, 0,  0,  0x3,  1,  0,  1,  0xF,  0,  0, 1,  1,  0}}, /* 0x18: data */
  63   {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, /* 0x20: reserve */
  64 };
  65
  66 //
  67 // IA32 Gdt register
  68 //
  69 GLOBAL_REMOVE_IF_UNREFERENCED IA32_DESCRIPTOR mGdt = {
  70   sizeof (mGdtEntries) - 1,
  71   (UINTN) mGdtEntries
  72   };
  73 /**
  74   Assembly function to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
  75   long mode.
  76   @param  Function     The 32bit code entry to be executed.
  77   @param  Param1       The first parameter to pass to 32bit code
  78   @param  Param2       The second parameter to pass to 32bit code
  79   @param  InternalGdtr The GDT and GDT descriptor used by this library
  80
  81   @retval EFI_SUCCESS  Execute 32bit code successfully.
  82   @retval other        Something wrong when execute the 32bit code
  83 **/
  84 EFI_STATUS
  85 AsmExecute32BitCode (
  86   IN UINT64           Function,
  87   IN UINT64           Param1,
  88   IN UINT64           Param2,
  89   IN IA32_DESCRIPTOR  *InternalGdtr
  90   );
  91
  92 /**
  93   Wrapper for a thunk  to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
  94   long mode.
  95
  96   @param  Function     The 32bit code entry to be executed.
  97   @param  Param1       The first parameter to pass to 32bit code
  98   @param  Param2       The second parameter to pass to 32bit code
  99   @retval EFI_SUCCESS  Execute 32bit code successfully.
 100   @retval other        Something wrong when execute the 32bit code
 101
 102 **/
 103 EFI_STATUS
 104 Execute32BitCode (
 105   IN UINT64      Function,
 106   IN UINT64      Param1,
 107   IN UINT64      Param2
 108   )
 109 {
 110   EFI_STATUS                 Status;
 111   IA32_DESCRIPTOR            *Ia32Idtr;
 112   IA32_DESCRIPTOR            X64Idtr;
 113   UINTN                      Ia32IdtEntryCount;
 114   UINTN                      Index;
 115   IA32_IDT_ENTRY             *Ia32IdtEntry;
 116
 117   //
 118   // Save x64 IDT Descriptor
 119   //
 120   AsmReadIdtr ((IA32_DESCRIPTOR *) &X64Idtr);
 121
 122   //
 123   // Get the IA32 IDT Descriptor saved in 16 bytes in front of X64 IDT table.
 124   //
 125   Ia32Idtr = (IA32_DESCRIPTOR *) (UINTN) (X64Idtr.Base - 16);
 126   Ia32IdtEntryCount = (Ia32Idtr->Limit + 1) / sizeof (IA32_IDT_ENTRY);
 127
 128   Ia32IdtEntry = (IA32_IDT_ENTRY *)(Ia32Idtr->Base);
 129   for (Index = 0; Index < Ia32IdtEntryCount; Index ++ ) {
 130     //
 131     // Use the new Code Selector value
 132     //
 133     Ia32IdtEntry[Index].Bits.Selector = COMPATIBILITY_MODE_SELECTOR;
 134   }
 135
 136   //
 137   // Setup IA32 IDT table for 32-bit framework Boot Script code
 138   //
 139   AsmWriteIdtr (Ia32Idtr);
 140
 141   ASSERT (Function != 0);
 142
 143   Status = AsmExecute32BitCode (
 144              Function,
 145              Param1,
 146              Param2,
 147              &mGdt
 148              );
 149
 150   //
 151   // Restore X64 IDT table
 152   //
 153   AsmWriteIdtr ((IA32_DESCRIPTOR *) &X64Idtr);
 154
 155   return Status;
 156 }
 157