diff options
Diffstat (limited to 'IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.asm')
| -rw-r--r-- | IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.asm | 230 |
1 files changed, 0 insertions, 230 deletions
diff --git a/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.asm b/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.asm deleted file mode 100644 index 70e7b5f408..0000000000 --- a/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.asm +++ /dev/null @@ -1,230 +0,0 @@ -;
-; Copyright (c) 2014, 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.
-;
-;
-; Module Name:
-;
-; Thunk64To32.asm
-;
-; Abstract:
-;
-; This is the assembly code to transition from long mode to compatibility mode to execute 32-bit code and then
-; transit back to long mode.
-;
-;-------------------------------------------------------------------------------
- .code
-;----------------------------------------------------------------------------
-; Procedure: AsmExecute32BitCode
-;
-; Input: None
-;
-; Output: None
-;
-; Prototype: UINT32
-; AsmExecute32BitCode (
-; IN UINT64 Function,
-; IN UINT64 Param1,
-; IN UINT64 Param2,
-; IN IA32_DESCRIPTOR *InternalGdtr
-; );
-;
-;
-; Description: A thunk function to execute 32-bit code in long mode.
-;
-;----------------------------------------------------------------------------
-AsmExecute32BitCode PROC
- ;
- ; save IFLAG and disable it
- ;
- pushfq
- cli
-
- ;
- ; save orignal GDTR and CS
- ;
- mov rax, ds
- push rax
- mov rax, cs
- push rax
- sub rsp, 10h
- sgdt fword ptr [rsp]
- ;
- ; load internal GDT
- ;
- lgdt fword ptr [r9]
- ;
- ; Save general purpose register and rflag register
- ;
- pushfq
- push rdi
- push rsi
- push rbp
- push rbx
-
- ;
- ; save CR3
- ;
- mov rax, cr3
- mov rbp, rax
-
- ;
- ; Prepare the CS and return address for the transition from 32-bit to 64-bit mode
- ;
- mov rax, 10h ; load long mode selector
- shl rax, 32
- mov r9, OFFSET ReloadCS ;Assume the ReloadCS is under 4G
- or rax, r9
- push rax
- ;
- ; Save parameters for 32-bit function call
- ;
- mov rax, r8
- shl rax, 32
- or rax, rdx
- push rax
- ;
- ; save the 32-bit function entry and the return address into stack which will be
- ; retrieve in compatibility mode.
- ;
- mov rax, OFFSET ReturnBack ;Assume the ReloadCS is under 4G
- shl rax, 32
- or rax, rcx
- push rax
-
- ;
- ; let rax save DS
- ;
- mov rax, 018h
-
- ;
- ; Change to Compatible Segment
- ;
- mov rcx, 08h ; load compatible mode selector
- shl rcx, 32
- mov rdx, OFFSET Compatible ; assume address < 4G
- or rcx, rdx
- push rcx
- retf
-
-Compatible:
- ; reload DS/ES/SS to make sure they are correct referred to current GDT
- mov ds, ax
- mov es, ax
- mov ss, ax
-
- ;
- ; Disable paging
- ;
- mov rcx, cr0
- btc ecx, 31
- mov cr0, rcx
- ;
- ; Clear EFER.LME
- ;
- mov ecx, 0C0000080h
- rdmsr
- btc eax, 8
- wrmsr
-
-; Now we are in protected mode
- ;
- ; Call 32-bit function. Assume the function entry address and parameter value is less than 4G
- ;
- pop rax ; Here is the function entry
- ;
- ; Now the parameter is at the bottom of the stack, then call in to IA32 function.
- ;
- jmp rax
-ReturnBack:
- mov ebx, eax ; save return status
- pop rcx ; drop param1
- pop rcx ; drop param2
-
- ;
- ; restore CR4
- ;
- mov rax, cr4
- bts eax, 5
- mov cr4, rax
-
- ;
- ; restore CR3
- ;
- mov eax, ebp
- mov cr3, rax
-
- ;
- ; Set EFER.LME to re-enable ia32-e
- ;
- mov ecx, 0C0000080h
- rdmsr
- bts eax, 8
- wrmsr
- ;
- ; Enable paging
- ;
- mov rax, cr0
- bts eax, 31
- mov cr0, rax
-; Now we are in compatible mode
-
- ;
- ; Reload cs register
- ;
- retf
-ReloadCS:
- ;
- ; Now we're in Long Mode
- ;
- ;
- ; Restore C register and eax hold the return status from 32-bit function.
- ; Note: Do not touch rax from now which hold the return value from IA32 function
- ;
- mov eax, ebx ; put return status to EAX
- pop rbx
- pop rbp
- pop rsi
- pop rdi
- popfq
- ;
- ; Switch to orignal GDT and CS. here rsp is pointer to the orignal GDT descriptor.
- ;
- lgdt fword ptr[rsp]
- ;
- ; drop GDT descriptor in stack
- ;
- add rsp, 10h
- ;
- ; switch to orignal CS and GDTR
- ;
- pop r9 ; get CS
- shl r9, 32 ; rcx[32..47] <- Cs
- mov rcx, OFFSET @F
- or rcx, r9
- push rcx
- retf
-@@:
- ;
- ; Reload original DS/ES/SS
- ;
- pop rcx
- mov ds, rcx
- mov es, rcx
- mov ss, rcx
-
- ;
- ; Restore IFLAG
- ;
- popfq
-
- ret
-AsmExecute32BitCode ENDP
-
- END
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