diff options
Diffstat (limited to 'EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/X64/Thunk16.asm')
| -rw-r--r-- | EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/X64/Thunk16.asm | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/X64/Thunk16.asm b/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/X64/Thunk16.asm new file mode 100644 index 0000000..243c053 --- /dev/null +++ b/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/X64/Thunk16.asm @@ -0,0 +1,251 @@ +; Copyright (c) 2004, 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: +; +; Thunk.asm +; +; Abstract: +; +; Real mode thunk +; +;------------------------------------------------------------------------------ + +EXTERNDEF m16Start:BYTE +EXTERNDEF m16Size:WORD +EXTERNDEF mThunk16Attr:WORD +EXTERNDEF m16Gdt:WORD +EXTERNDEF m16GdtrBase:WORD +EXTERNDEF mTransition:WORD + +THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15 EQU 2 +THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL EQU 4 + +IA32_REGS STRUC 4t +_EDI DD ? +_ESI DD ? +_EBP DD ? +_ESP DD ? +_EBX DD ? +_EDX DD ? +_ECX DD ? +_EAX DD ? +_DS DW ? +_ES DW ? +_FS DW ? +_GS DW ? +_EFLAGS DQ ? +_EIP DD ? +_CS DW ? +_SS DW ? +IA32_REGS ENDS + + .const + +m16Size DW InternalAsmThunk16 - m16Start +mThunk16Attr DW _ThunkAttr - m16Start +m16Gdt DW _NullSegDesc - m16Start +m16GdtrBase DW _16GdtrBase - m16Start +mTransition DW _EntryPoint - m16Start + + .code + +m16Start LABEL BYTE + +SavedGdt LABEL FWORD + DW ? + DQ ? + +;------------------------------------------------------------------------------ +; _BackFromUserCode() takes control in real mode after 'retf' has been executed +; by user code. It will be shadowed to somewhere in memory below 1MB. +;------------------------------------------------------------------------------ +_BackFromUserCode PROC + DB 16h ; push ss + DB 0eh ; push cs + DB 66h + call @Base ; push eip +@Base: + DB 66h + push 0 ; reserved high order 32 bits of EFlags + pushf ; pushfd actually + cli ; disable interrupts + push gs + push fs + DB 6 ; push es + DB 1eh ; push ds + DB 66h, 60h ; pushad + DB 66h, 0bah ; mov edx, imm32 +_ThunkAttr DD ? + test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15 + jz @1 + mov eax, 15cd2401h ; mov ax, 2401h & int 15h + cli ; disable interrupts + jnc @2 +@1: + test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL + jz @2 + in al, 92h + or al, 2 + out 92h, al ; deactivate A20M# +@2: + xor ax, ax ; xor eax, eax + mov eax, ss + lea bp, [esp + sizeof (IA32_REGS)] + mov word ptr (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._ESP, bp + mov ebx, (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._EIP + shl ax, 4 ; shl eax, 4 + add bp, ax ; add ebp, eax + DB 66h, 0b8h ; mov eax, imm32 +SavedCr4 DD ? + mov cr4, rax + DB 66h, 2eh + lgdt fword ptr [rdi + (SavedGdt - @Base)] + DB 66h + mov ecx, 0c0000080h + rdmsr + or ah, 1 + wrmsr + DB 66h, 0b8h ; mov eax, imm32 +SavedCr0 DD ? + mov cr0, rax + DB 0b8h ; mov ax, imm16 +SavedSs DW ? + mov ss, eax + DB 66h, 0bch ; mov esp, imm32 +SavedEsp DD ? + DB 66h + retf ; return to protected mode +_BackFromUserCode ENDP + +_EntryPoint DD _ToUserCode - m16Start + DW 8h +_16Gdtr LABEL FWORD + DW GdtEnd - _NullSegDesc - 1 +_16GdtrBase DQ _NullSegDesc +_16Idtr FWORD (1 SHL 10) - 1 + +;------------------------------------------------------------------------------ +; _ToUserCode() takes control in real mode before passing control to user code. +; It will be shadowed to somewhere in memory below 1MB. +;------------------------------------------------------------------------------ +_ToUserCode PROC + mov edi, ss + mov ss, edx ; set new segment selectors + mov ds, edx + mov es, edx + mov fs, edx + mov gs, edx + DB 66h + mov ecx, 0c0000080h + mov cr0, rax ; real mode starts at next instruction + rdmsr + and ah, NOT 1 + wrmsr + mov cr4, rbp + mov ss, esi ; set up 16-bit stack segment + xchg sp, bx ; set up 16-bit stack pointer + DB 66h + call @Base ; push eip +@Base: + pop bp ; ebp <- address of @Base + push [esp + sizeof (IA32_REGS) + 2] + lea eax, [rsi + (@RealMode - @Base)] + push rax + retf +@RealMode: + DB 2eh ; cs: + mov [rsi + (SavedSs - @Base)], edi + DB 2eh ; cs: + mov [rsi + (SavedEsp - @Base)], bx + DB 66h, 2eh ; CS and operand size override + lidt fword ptr [rsi + (_16Idtr - @Base)] + DB 66h, 61h ; popad + DB 1fh ; pop ds + DB 07h ; pop es + pop fs + pop gs + popf ; popfd + lea sp, [esp + 4] ; skip high order 32 bits of EFlags + DB 66h + retf ; transfer control to user code +_ToUserCode ENDP + +_NullSegDesc DQ 0 +_16CsDesc LABEL QWORD + DW -1 + DW 0 + DB 0 + DB 9bh + DB 8fh ; 16-bit segment, 4GB limit + DB 0 +_16DsDesc LABEL QWORD + DW -1 + DW 0 + DB 0 + DB 93h + DB 8fh ; 16-bit segment, 4GB limit + DB 0 +GdtEnd LABEL QWORD + +;------------------------------------------------------------------------------ +; IA32_REGISTER_SET * +; EFIAPI +; InternalAsmThunk16 ( +; IN IA32_REGISTER_SET *RegisterSet, +; IN OUT VOID *Transition +; ); +;------------------------------------------------------------------------------ +InternalAsmThunk16 PROC USES rbp rbx rsi rdi + mov r10d, ds + mov r11d, es + push fs + push gs + mov rsi, rcx + movzx r8d, (IA32_REGS ptr [rsi])._SS + mov edi, (IA32_REGS ptr [rsi])._ESP + lea rdi, [edi - (sizeof (IA32_REGS) + 4)] + imul eax, r8d, 16 ; eax <- r8d(stack segment) * 16 + mov ebx, edi ; ebx <- stack for 16-bit code + push sizeof (IA32_REGS) / 4 + add edi, eax ; edi <- linear address of 16-bit stack + pop rcx + rep movsd ; copy RegSet + lea ecx, [rdx + (SavedCr4 - m16Start)] + mov eax, edx ; eax <- transition code address + and edx, 0fh + shl eax, 12 + lea edx, [rdx + (_BackFromUserCode - m16Start)] + mov ax, dx + stosd ; [edi] <- return address of user code + sgdt fword ptr [rcx + (SavedGdt - SavedCr4)] + sidt fword ptr [rsp + 38h] ; save IDT stack in argument space + mov rax, cr0 + mov [rcx + (SavedCr0 - SavedCr4)], eax + and eax, 7ffffffeh ; clear PE, PG bits + mov rbp, cr4 + mov [rcx], ebp ; save CR4 in SavedCr4 + and ebp, 300h ; clear all but PCE and OSFXSR bits + mov esi, r8d ; esi <- 16-bit stack segment + push 10h + pop rdx ; rdx <- selector for data segments + lgdt fword ptr [rcx + (_16Gdtr - SavedCr4)] + pushfq + call fword ptr [rcx + (_EntryPoint - SavedCr4)] + popfq + lidt fword ptr [rsp + 38h] ; restore protected mode IDTR + lea eax, [rbp - sizeof (IA32_REGS)] + pop gs + pop fs + mov es, r11d + mov ds, r10d + ret +InternalAsmThunk16 ENDP + + END |