From 24498828f71992e9fd87dd516dcbb5ccd5b71ff0 Mon Sep 17 00:00:00 2001 From: Liming Gao Date: Wed, 8 Jun 2016 17:51:15 +0800 Subject: [PATCH] IntelFsp2WrapperPkg BaseFspWrapperApiLib: Convert X64/Thunk64To32.asm to NASM Manually convert X64/Thunk64To32.asm to X64/Thunk64To32.nasm Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Liming Gao --- .../BaseFspWrapperApiLib.inf | 1 + .../BaseFspWrapperApiLib/X64/Thunk64To32.nasm | 230 ++++++++++++++++++ 2 files changed, 231 insertions(+) create mode 100644 IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm diff --git a/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/BaseFspWrapperApiLib.inf b/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/BaseFspWrapperApiLib.inf index 870c3fbee4..f2cef05a24 100644 --- a/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/BaseFspWrapperApiLib.inf +++ b/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/BaseFspWrapperApiLib.inf @@ -47,6 +47,7 @@ X64/DispatchExecute.c X64/Thunk64To32.asm X64/Thunk64To32.S + X64/Thunk64To32.nasm ################################################################################ # diff --git a/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm b/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm new file mode 100644 index 0000000000..bcc6d70a73 --- /dev/null +++ b/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm @@ -0,0 +1,230 @@ +; +; Copyright (c) 2016, Intel Corporation. All rights reserved.
+; 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.nasm +; +; 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. +; +;------------------------------------------------------------------------------- + DEFAULT REL + SECTION .text +;---------------------------------------------------------------------------- +; 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. +; +;---------------------------------------------------------------------------- +global ASM_PFX(AsmExecute32BitCode) +ASM_PFX(AsmExecute32BitCode): + ; + ; save IFLAG and disable it + ; + pushfq + cli + + ; + ; save orignal GDTR and CS + ; + mov rax, ds + push rax + mov rax, cs + push rax + sub rsp, 0x10 + sgdt [rsp] + ; + ; load internal GDT + ; + lgdt [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, dword 0x10 ; load long mode selector + shl rax, 32 + mov r9, 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, ReturnBack ;Assume the ReloadCS is under 4G + shl rax, 32 + or rax, rcx + push rax + + ; + ; let rax save DS + ; + mov rax, dword 0x18 + + ; + ; Change to Compatible Segment + ; + mov rcx, dword 0x8 ; load compatible mode selector + shl rcx, 32 + mov rdx, 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, 0xC0000080 + 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, 0xC0000080 + 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 [rsp] + ; + ; drop GDT descriptor in stack + ; + add rsp, 0x10 + ; + ; switch to orignal CS and GDTR + ; + pop r9 ; get CS + shl r9, 32 ; rcx[32..47] <- Cs + mov rcx, .0 + or rcx, r9 + push rcx + retf +.0: + ; + ; Reload original DS/ES/SS + ; + pop rcx + mov ds, rcx + mov es, rcx + mov ss, rcx + + ; + ; Restore IFLAG + ; + popfq + + ret + -- 2.39.2