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MdePkg BaseLib NASM Thunk16: Remove remaining 'DB' code

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Convert remaining 'DB' code to assembly code by:
* Move instruction immediate data labels to end of instruction
* Use strict keyword to make sure immediate data size is not optimized

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16024 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Jordan Justen
2014-09-01 17:23:57 +00:00
committed by jljusten
parent f6888eea46
commit 7458df400c
2 changed files with 46 additions and 49 deletions
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48
MdePkg/Library/BaseLib/X64/Thunk16.nasm
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@@ -57,7 +57,7 @@ SECTION .data
; These are global constant to convey information to C code.
;
ASM_PFX(m16Size) DW InternalAsmThunk16 - ASM_PFX(m16Start)
ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttr - ASM_PFX(m16Start)
ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttrEnd - 4 - ASM_PFX(m16Start)
ASM_PFX(m16Gdt) DW _NullSeg - ASM_PFX(m16Start)
ASM_PFX(m16GdtrBase) DW _16GdtrBase - ASM_PFX(m16Start)
ASM_PFX(mTransition) DW _EntryPoint - ASM_PFX(m16Start)
@@ -93,8 +93,8 @@ o32 call dword .Base ; push eip
push es
push ds
pushad
DB 66h, 0bah ; mov edx, imm32
.ThunkAttr: dd 0
mov edx, strict dword 0
.ThunkAttrEnd:
test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15
jz .1
mov ax, 2401h
@@ -117,27 +117,25 @@ o32 call dword .Base ; push eip
add ebp, eax ; add ebp, eax
mov eax, cs
shl eax, 4
lea eax, [eax + ebx + (.64BitCode - .Base)]
mov [cs:bx + (.64Eip - .Base)], eax
DB 66h, 0b8h ; mov eax, imm32
.SavedCr4: DD 0
lea eax, [eax + ebx + (.X64JmpEnd - .Base)]
mov [cs:bx + (.X64JmpEnd - 6 - .Base)], eax
mov eax, strict dword 0
.SavedCr4End:
mov cr4, eax
o32 lgdt [cs:bx + (SavedGdt - .Base)]
mov ecx, 0c0000080h
rdmsr
or ah, 1
wrmsr
DB 66h, 0b8h ; mov eax, imm32
.SavedCr0: DD 0
mov eax, strict dword 0
.SavedCr0End:
mov cr0, eax
DB 66h, 0eah ; jmp far cs:.64Bit
.64Eip: DD 0
.SavedCs: DW 0
.64BitCode:
jmp 0:strict dword 0
.X64JmpEnd:
BITS 64
nop
db 048h, 0bch ; mov rsp, imm64
.SavedSp: DQ 0 ; restore stack
mov rsp, strict qword 0
.SavedSpEnd:
nop
ret
@@ -258,7 +256,7 @@ BITS 64
add edi, eax ; edi <- linear address of 16-bit stack
pop rcx
rep movsd ; copy RegSet
lea ecx, [rdx + (_BackFromUserCode.SavedCr4 - ASM_PFX(m16Start))]
lea ecx, [rdx + (_BackFromUserCode.SavedCr4End - ASM_PFX(m16Start))]
mov eax, edx ; eax <- transition code address
and edx, 0fh
shl eax, 12 ; segment address in high order 16 bits
@@ -267,11 +265,11 @@ BITS 64
sgdt [rsp + 60h] ; save GDT stack in argument space
movzx r10, word [rsp + 60h] ; r10 <- GDT limit
lea r11, [rcx + (InternalAsmThunk16 - _BackFromUserCode.SavedCr4) + 0xf]
lea r11, [rcx + (InternalAsmThunk16 - _BackFromUserCode.SavedCr4End) + 0xf]
and r11, ~0xf ; r11 <- 16-byte aligned shadowed GDT table in real mode buffer
mov [rcx + (SavedGdt - _BackFromUserCode.SavedCr4)], r10w ; save the limit of shadowed GDT table
mov [rcx + (SavedGdt - _BackFromUserCode.SavedCr4) + 2], r11 ; save the base address of shadowed GDT table
mov [rcx + (SavedGdt - _BackFromUserCode.SavedCr4End)], r10w ; save the limit of shadowed GDT table
mov [rcx + (SavedGdt - _BackFromUserCode.SavedCr4End) + 2], r11 ; save the base address of shadowed GDT table
mov rsi, [rsp + 62h] ; rsi <- the original GDT base address
xchg rcx, r10 ; save rcx to r10 and initialize rcx to be the limit of GDT table
@@ -283,24 +281,24 @@ BITS 64
sidt [rsp + 50h] ; save IDT stack in argument space
mov rax, cr0
mov [rcx + (_BackFromUserCode.SavedCr0 - _BackFromUserCode.SavedCr4)], eax
mov [rcx + (_BackFromUserCode.SavedCr0End - 4 - _BackFromUserCode.SavedCr4End)], eax
and eax, 7ffffffeh ; clear PE, PG bits
mov rbp, cr4
mov [rcx], ebp ; save CR4 in _BackFromUserCode.SavedCr4
mov [rcx - 4], ebp ; save CR4 in _BackFromUserCode.SavedCr4End - 4
and ebp, ~30h ; clear PAE, PSE bits
mov esi, r8d ; esi <- 16-bit stack segment
push DATA32
pop rdx ; rdx <- 32-bit data segment selector
lgdt [rcx + (_16Gdtr - _BackFromUserCode.SavedCr4)]
lgdt [rcx + (_16Gdtr - _BackFromUserCode.SavedCr4End)]
mov ss, edx
pushfq
lea edx, [rdx + DATA16 - DATA32]
lea r8, [REL .RetFromRealMode]
push r8
mov r8d, cs
mov [rcx + (_BackFromUserCode.SavedCs - _BackFromUserCode.SavedCr4)], r8w
mov [rcx + (_BackFromUserCode.SavedSp - _BackFromUserCode.SavedCr4)], rsp
jmp dword far [rcx + (_EntryPoint - _BackFromUserCode.SavedCr4)]
mov [rcx + (_BackFromUserCode.X64JmpEnd - 2 - _BackFromUserCode.SavedCr4End)], r8w
mov [rcx + (_BackFromUserCode.SavedSpEnd - 8 - _BackFromUserCode.SavedCr4End)], rsp
jmp dword far [rcx + (_EntryPoint - _BackFromUserCode.SavedCr4End)]
.RetFromRealMode:
popfq
lgdt [rsp + 60h] ; restore protected mode GDTR