d3febfd9ad
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3790 Replace Opcode with the corresponding instructions. The code changes have been verified with CompareBuild.py tool, which can be used to compare the results of two different EDK II builds to determine if they generate the same binaries. (tool link: https://github.com/mdkinney/edk2/tree/sandbox/CompareBuild) Signed-off-by: Jason Lou <yun.lou@intel.com> Cc: Michael D Kinney <michael.d.kinney@intel.com> Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn> Cc: Zhiguang Liu <zhiguang.liu@intel.com>
78 lines
3.0 KiB
NASM
78 lines
3.0 KiB
NASM
;------------------------------------------------------------------------------
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;
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; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
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; SPDX-License-Identifier: BSD-2-Clause-Patent
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;
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; Module Name:
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;
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; DisablePaging64.Asm
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;
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; Abstract:
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;
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; AsmDisablePaging64 function
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;
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; Notes:
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;
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;------------------------------------------------------------------------------
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DEFAULT REL
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SECTION .text
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;------------------------------------------------------------------------------
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; VOID
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; EFIAPI
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; InternalX86DisablePaging64 (
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; IN UINT16 Cs,
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; IN UINT32 EntryPoint,
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; IN UINT32 Context1, OPTIONAL
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; IN UINT32 Context2, OPTIONAL
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; IN UINT32 NewStack
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; );
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;------------------------------------------------------------------------------
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global ASM_PFX(InternalX86DisablePaging64)
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ASM_PFX(InternalX86DisablePaging64):
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cli
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lea rsi, [.0] ; rsi <- The start address of transition code
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mov edi, [rsp + 0x28] ; rdi <- New stack
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lea rax, [mTransitionEnd] ; rax <- end of transition code
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sub rax, rsi ; rax <- The size of transition piece code
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add rax, 4 ; Round RAX up to the next 4 byte boundary
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and al, 0xfc
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sub rdi, rax ; rdi <- Use stack to hold transition code
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mov r10d, edi ; r10 <- The start address of transicition code below 4G
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push rcx ; save rcx to stack
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mov rcx, rax ; rcx <- The size of transition piece code
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rep movsb ; copy transition code to top of new stack which must be below 4GB
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pop rcx ; restore rcx
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mov esi, r8d
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mov edi, r9d
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mov eax, r10d ; eax <- start of the transition code on the stack
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sub eax, 4 ; eax <- One slot below transition code on the stack
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push rcx ; push Cs to stack
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push r10 ; push address of tansition code on stack
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retfq
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; Start of transition code
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.0:
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mov esp, eax ; set up new stack
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mov rax, cr0
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btr eax, 31 ; Clear CR0.PG
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mov cr0, rax ; disable paging and caches
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mov ebx, edx ; save EntryPoint to rbx, for rdmsr will overwrite rdx
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mov ecx, 0xc0000080
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rdmsr
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and ah, ~ 1 ; clear LME
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wrmsr
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mov rax, cr4
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and al, ~ (1 << 5) ; clear PAE
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mov cr4, rax
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push rdi ; push Context2
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push rsi ; push Context1
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call rbx ; transfer control to EntryPoint
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hlt ; no one should get here
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mTransitionEnd:
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