/** @file | |
Execute 32-bit code in Long Mode | |
Provide a thunk function to transition from long mode to compatibility mode to execute 32-bit code and then transit | |
back to long mode. | |
Copyright (c) 2010 - 2012, 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 "ScriptSave.h" | |
#pragma pack(1) | |
typedef union { | |
struct { | |
UINT32 LimitLow : 16; | |
UINT32 BaseLow : 16; | |
UINT32 BaseMid : 8; | |
UINT32 Type : 4; | |
UINT32 System : 1; | |
UINT32 Dpl : 2; | |
UINT32 Present : 1; | |
UINT32 LimitHigh : 4; | |
UINT32 Software : 1; | |
UINT32 Reserved : 1; | |
UINT32 DefaultSize : 1; | |
UINT32 Granularity : 1; | |
UINT32 BaseHigh : 8; | |
} Bits; | |
UINT64 Uint64; | |
} IA32_GDT; | |
/// | |
/// Byte packed structure for an IA-32 Interrupt Gate Descriptor. | |
/// | |
typedef union { | |
struct { | |
UINT32 OffsetLow:16; ///< Offset bits 15..0. | |
UINT32 Selector:16; ///< Selector. | |
UINT32 Reserved_0:8; ///< Reserved. | |
UINT32 GateType:8; ///< Gate Type. See #defines above. | |
UINT32 OffsetHigh:16; ///< Offset bits 31..16. | |
} Bits; | |
UINT64 Uint64; | |
} IA32_IDT_ENTRY; | |
#pragma pack() | |
#define COMPATIBILITY_MODE_SELECTOR 8 | |
// | |
// Global Descriptor Table (GDT) | |
// | |
GLOBAL_REMOVE_IF_UNREFERENCED IA32_GDT mGdtEntries[] = { | |
{{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}, /* 0x0: reserve */ | |
{{0xFFFF, 0, 0, 0xB, 1, 0, 1, 0xF, 0, 0, 1, 1, 0}}, /* 0x8: compatibility mode */ | |
{{0xFFFF, 0, 0, 0xB, 1, 0, 1, 0xF, 0, 1, 0, 1, 0}}, /* 0x10: for long mode */ | |
{{0xFFFF, 0, 0, 0x3, 1, 0, 1, 0xF, 0, 0, 1, 1, 0}}, /* 0x18: data */ | |
{{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}, /* 0x20: reserve */ | |
}; | |
// | |
// IA32 Gdt register | |
// | |
GLOBAL_REMOVE_IF_UNREFERENCED IA32_DESCRIPTOR mGdt = { | |
sizeof (mGdtEntries) - 1, | |
(UINTN) mGdtEntries | |
}; | |
/** | |
Assembly function to transition from long mode to compatibility mode to execute 32-bit code and then transit back to | |
long mode. | |
@param Function The 32bit code entry to be executed. | |
@param Param1 The first parameter to pass to 32bit code | |
@param Param2 The second parameter to pass to 32bit code | |
@param InternalGdtr The GDT and GDT descriptor used by this library | |
@retval EFI_SUCCESS Execute 32bit code successfully. | |
@retval other Something wrong when execute the 32bit code | |
**/ | |
EFI_STATUS | |
AsmExecute32BitCode ( | |
IN UINT64 Function, | |
IN UINT64 Param1, | |
IN UINT64 Param2, | |
IN IA32_DESCRIPTOR *InternalGdtr | |
); | |
/** | |
Wrapper for a thunk to transition from long mode to compatibility mode to execute 32-bit code and then transit back to | |
long mode. | |
@param Function The 32bit code entry to be executed. | |
@param Param1 The first parameter to pass to 32bit code | |
@param Param2 The second parameter to pass to 32bit code | |
@retval EFI_SUCCESS Execute 32bit code successfully. | |
@retval other Something wrong when execute the 32bit code | |
**/ | |
EFI_STATUS | |
Execute32BitCode ( | |
IN UINT64 Function, | |
IN UINT64 Param1, | |
IN UINT64 Param2 | |
) | |
{ | |
EFI_STATUS Status; | |
IA32_DESCRIPTOR *Ia32Idtr; | |
IA32_DESCRIPTOR X64Idtr; | |
UINTN Ia32IdtEntryCount; | |
UINTN Index; | |
IA32_IDT_ENTRY *Ia32IdtEntry; | |
// | |
// Save x64 IDT Descriptor | |
// | |
AsmReadIdtr ((IA32_DESCRIPTOR *) &X64Idtr); | |
// | |
// Get the IA32 IDT Descriptor saved in 16 bytes in front of X64 IDT table. | |
// | |
Ia32Idtr = (IA32_DESCRIPTOR *) (UINTN) (X64Idtr.Base - 16); | |
Ia32IdtEntryCount = (Ia32Idtr->Limit + 1) / sizeof (IA32_IDT_ENTRY); | |
Ia32IdtEntry = (IA32_IDT_ENTRY *)(Ia32Idtr->Base); | |
for (Index = 0; Index < Ia32IdtEntryCount; Index ++ ) { | |
// | |
// Use the new Code Selector value | |
// | |
Ia32IdtEntry[Index].Bits.Selector = COMPATIBILITY_MODE_SELECTOR; | |
} | |
// | |
// Setup IA32 IDT table for 32-bit framework Boot Script code | |
// | |
AsmWriteIdtr (Ia32Idtr); | |
ASSERT (Function != 0); | |
Status = AsmExecute32BitCode ( | |
Function, | |
Param1, | |
Param2, | |
&mGdt | |
); | |
// | |
// Restore X64 IDT table | |
// | |
AsmWriteIdtr ((IA32_DESCRIPTOR *) &X64Idtr); | |
return Status; | |
} | |