[mirror_edk2.git] / MdePkg / Library / BaseLib / X64 / Thunk16.asm

;------------------------------------------------------------------------------\r
;\r
; Copyright (c) 2006, Intel Corporation\r
; All rights reserved. This program and the accompanying materials\r
; are licensed and made available under the terms and conditions of the BSD License\r
; which accompanies this distribution.  The full text of the license may be found at\r
; http://opensource.org/licenses/bsd-license.php\r
;\r
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
;\r
; Module Name:\r
;\r
;   Thunk.asm\r
;\r
; Abstract:\r
;\r
;   Real mode thunk\r
;\r
;------------------------------------------------------------------------------\r
\r
EXTERNDEF   m16Start:BYTE\r
EXTERNDEF   m16Size:WORD\r
EXTERNDEF   mThunk16Attr:WORD\r
EXTERNDEF   m16Gdt:WORD\r
EXTERNDEF   m16GdtrBase:WORD\r
EXTERNDEF   mTransition:WORD\r
\r
THUNK_ATTRIBUTE_BIG_REAL_MODE               EQU 1\r
THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15     EQU 2\r
THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL   EQU 4\r
\r
IA32_REGS   STRUC   4t\r
_EDI        DD      ?\r
_ESI        DD      ?\r
_EBP        DD      ?\r
_ESP        DD      ?\r
_EBX        DD      ?\r
_EDX        DD      ?\r
_ECX        DD      ?\r
_EAX        DD      ?\r
_DS         DW      ?\r
_ES         DW      ?\r
_FS         DW      ?\r
_GS         DW      ?\r
_EFLAGS     DQ      ?\r
_EIP        DD      ?\r
_CS         DW      ?\r
_SS         DW      ?\r
IA32_REGS   ENDS\r
\r
    .const\r
\r
m16Size         DW      offset InternalAsmThunk16 - offset m16Start\r
mThunk16Attr    DW      offset _ThunkAttr - offset m16Start\r
m16Gdt          DW      offset _NullSegDesc - offset m16Start\r
m16GdtrBase     DW      offset _16GdtrBase - offset m16Start\r
mTransition     DW      offset _EntryPoint - offset m16Start\r
\r
    .code\r
\r
m16Start    LABEL   BYTE\r
\r
SavedGdt        LABEL   FWORD\r
                DW      ?\r
                DQ      ?\r
\r
_BackFromUserCode   PROC\r
    DB      16h                         ; push ss\r
    DB      0eh                         ; push cs\r
    DB      66h\r
    call    @Base                       ; push eip\r
@Base:\r
    DB      66h\r
    push    0                           ; reserved high order 32 bits of EFlags\r
    pushf                               ; pushfd actually\r
    cli                                 ; disable interrupts\r
    push    gs\r
    push    fs\r
    DB      6                           ; push es\r
    DB      1eh                         ; push ds\r
    DB      66h, 60h                    ; pushad\r
    DB      66h, 0bah                   ; mov edx, imm32\r
_ThunkAttr  DD      ?\r
    test    dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
    jz      @1\r
    mov     eax, 15cd2401h              ; mov ax, 2401h & int 15h\r
    cli                                 ; disable interrupts\r
    jnc     @2\r
@1:\r
    test    dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL\r
    jz      @2\r
    in      al, 92h\r
    or      al, 2\r
    out     92h, al                     ; deactivate A20M#\r
@2:\r
    mov     eax, ss\r
    lea     bp, [esp + sizeof (IA32_REGS)]\r
    mov     word ptr (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._ESP, bp\r
    mov     ebx, (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._EIP\r
    shl     ax, 4                       ; shl eax, 4\r
    add     bp, ax                      ; add ebp, eax\r
    DB      66h, 0b8h                   ; mov eax, imm32\r
SavedCr4    DD      ?\r
    mov     cr4, rax\r
    DB      66h, 2eh\r
    lgdt    fword ptr [rdi + (offset SavedGdt - offset @Base)]\r
    DB      66h\r
    mov     ecx, 0c0000080h\r
    rdmsr\r
    or      ah, 1\r
    wrmsr\r
    DB      66h, 0b8h                   ; mov eax, imm32\r
SavedCr0    DD      ?\r
    mov     cr0, rax\r
    DB      0b8h                        ; mov ax, imm16\r
SavedSs     DW      ?\r
    mov     ss, eax\r
    DB      66h, 0bch                   ; mov esp, imm32\r
SavedEsp    DD      ?\r
    DB      66h\r
    retf                                ; return to protected mode\r
_BackFromUserCode   ENDP\r
\r
_EntryPoint     DD      offset _ToUserCode - offset m16Start\r
                DW      8h\r
_16Gdtr         LABEL   FWORD\r
                DW      offset GdtEnd - offset _NullSegDesc - 1\r
_16GdtrBase     DQ      offset _NullSegDesc\r
_16Idtr         FWORD   (1 SHL 10) - 1\r
\r
_ToUserCode PROC\r
    mov     edi, ss\r
    mov     ss, edx                     ; set new segment selectors\r
    mov     ds, edx\r
    mov     es, edx\r
    mov     fs, edx\r
    mov     gs, edx\r
    DB      66h\r
    mov     ecx, 0c0000080h\r
    mov     cr0, rax                    ; real mode starts at next instruction\r
    rdmsr\r
    and     ah, NOT 1\r
    wrmsr\r
    mov     cr4, rbp\r
    mov     ss, esi                     ; set up 16-bit stack segment\r
    xchg    sp, bx                      ; set up 16-bit stack pointer\r
    DB      66h\r
    call    @Base                       ; push eip\r
@Base:\r
    pop     bp                          ; ebp <- offset @Base\r
    DB      2eh                         ; cs:\r
    mov     [rsi + (offset SavedSs - offset @Base)], edi\r
    DB      2eh                         ; cs:\r
    mov     [rsi + (offset SavedEsp - offset @Base)], bx\r
    DB      66h, 2eh                    ; CS and operand size override\r
    lidt    fword ptr [rsi + (offset _16Idtr - offset @Base)]\r
    DB      66h, 61h                    ; popad\r
    DB      1fh                         ; pop ds\r
    DB      07h                         ; pop es\r
    pop     fs\r
    pop     gs\r
    popf                                ; popfd\r
    lea     sp, [esp + 4]               ; skip high order 32 bits of EFlags\r
    DB      66h\r
    retf                                ; transfer control to user code\r
_ToUserCode ENDP\r
\r
_NullSegDesc    DQ      0\r
_16CsDesc       LABEL   QWORD\r
                DW      -1\r
                DW      0\r
                DB      0\r
                DB      9bh\r
                DB      8fh             ; 16-bit segment, 4GB limit\r
                DB      0\r
_16DsDesc       LABEL   QWORD\r
                DW      -1\r
                DW      0\r
                DB      0\r
                DB      93h\r
                DB      8fh             ; 16-bit segment, 4GB limit\r
                DB      0\r
GdtEnd          LABEL   QWORD\r
\r
;\r
;   @param  RegSet  Pointer to a IA32_DWORD_REGS structure\r
;   @param  Transition  Pointer to the transition code\r
;   @return The address of the 16-bit stack after returning from user code\r
;\r
InternalAsmThunk16  PROC    USES    rbp rbx rsi rdi\r
    mov     r10d, ds\r
    mov     r11d, es\r
    push    fs\r
    push    gs\r
    mov     rsi, rcx\r
    movzx   r8d, (IA32_REGS ptr [rsi])._SS\r
    mov     edi, (IA32_REGS ptr [rsi])._ESP\r
    lea     rdi, [edi - (sizeof (IA32_REGS) + 4)]\r
    imul    eax, r8d, 16                ; eax <- r8d(stack segment) * 16\r
    mov     ebx, edi                    ; ebx <- stack offset for 16-bit code\r
    push    sizeof (IA32_REGS) / 4\r
    add     edi, eax                    ; edi <- linear address of 16-bit stack\r
    pop     rcx\r
    rep     movsd                       ; copy RegSet\r
    lea     ecx, [rdx + (offset SavedCr4 - offset m16Start)]\r
    mov     eax, edx                    ; eax <- transition code address\r
    and     edx, 0fh\r
    shl     eax, 12\r
    lea     edx, [rdx + (offset _BackFromUserCode - offset m16Start)]\r
    mov     ax, dx\r
    stosd                               ; [edi] <- return address of user code\r
    sgdt    fword ptr [rcx + (offset SavedGdt - offset SavedCr4)]\r
    sidt    fword ptr [rsp + 38h]       ; save IDT stack in argument space\r
    mov     rax, cr0\r
    mov     [rcx + (offset SavedCr0 - offset SavedCr4)], eax\r
    and     eax, 7ffffffeh              ; clear PE, PG bits\r
    mov     rbp, cr4\r
    mov     [rcx], ebp                  ; save CR4 in SavedCr4\r
    and     ebp, 300h                   ; clear all but PCE and OSFXSR bits\r
    mov     esi, r8d                    ; esi <- 16-bit stack segment\r
    push    10h\r
    pop     rdx                         ; rdx <- selector for data segments\r
    lgdt    fword ptr [rcx + (offset _16Gdtr - offset SavedCr4)]\r
    call    fword ptr [rcx + (offset _EntryPoint - offset SavedCr4)]\r
    lidt    fword ptr [rsp + 38h]       ; restore protected mode IDTR\r
    lea     eax, [rbp - sizeof (IA32_REGS)]\r
    pop     gs\r
    pop     fs\r
    mov     es, r11d\r
    mov     ds, r10d\r
    ret\r
InternalAsmThunk16  ENDP\r
\r
    END\r
Commit	Line	Data
878ddf1f	1	;------------------------------------------------------------------------------\r
	2	;\r
	3	; Copyright (c) 2006, Intel Corporation\r
	4	; All rights reserved. This program and the accompanying materials\r
	5	; are licensed and made available under the terms and conditions of the BSD License\r
	6	; which accompanies this distribution. The full text of the license may be found at\r
	7	; http://opensource.org/licenses/bsd-license.php\r
	8	;\r
	9	; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	10	; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	11	;\r
	12	; Module Name:\r
	13	;\r
	14	; Thunk.asm\r
	15	;\r
	16	; Abstract:\r
	17	;\r
	18	; Real mode thunk\r
	19	;\r
	20	;------------------------------------------------------------------------------\r
	21	\r
97d92bda	22	EXTERNDEF m16Start:BYTE\r
	23	EXTERNDEF m16Size:WORD\r
	24	EXTERNDEF mThunk16Attr:WORD\r
	25	EXTERNDEF m16Gdt:WORD\r
	26	EXTERNDEF m16GdtrBase:WORD\r
	27	EXTERNDEF mTransition:WORD\r
878ddf1f	28	\r
97d92bda	29	THUNK_ATTRIBUTE_BIG_REAL_MODE EQU 1\r
	30	THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15 EQU 2\r
	31	THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL EQU 4\r
878ddf1f	32	\r
	33	IA32_REGS STRUC 4t\r
	34	_EDI DD ?\r
	35	_ESI DD ?\r
	36	_EBP DD ?\r
	37	_ESP DD ?\r
	38	_EBX DD ?\r
	39	_EDX DD ?\r
	40	_ECX DD ?\r
	41	_EAX DD ?\r
	42	_DS DW ?\r
	43	_ES DW ?\r
	44	_FS DW ?\r
	45	_GS DW ?\r
97d92bda	46	_EFLAGS DQ ?\r
878ddf1f	47	_EIP DD ?\r
	48	_CS DW ?\r
	49	_SS DW ?\r
	50	IA32_REGS ENDS\r
	51	\r
97d92bda	52	.const\r
	53	\r
	54	m16Size DW offset InternalAsmThunk16 - offset m16Start\r
	55	mThunk16Attr DW offset _ThunkAttr - offset m16Start\r
	56	m16Gdt DW offset _NullSegDesc - offset m16Start\r
	57	m16GdtrBase DW offset _16GdtrBase - offset m16Start\r
	58	mTransition DW offset _EntryPoint - offset m16Start\r
	59	\r
	60	.code\r
	61	\r
	62	m16Start LABEL BYTE\r
	63	\r
	64	SavedGdt LABEL FWORD\r
	65	DW ?\r
	66	DQ ?\r
	67	\r
	68	_BackFromUserCode PROC\r
	69	DB 16h ; push ss\r
	70	DB 0eh ; push cs\r
878ddf1f	71	DB 66h\r
97d92bda	72	call @Base ; push eip\r
97d92bda	73	@Base:\r
878ddf1f	74	DB 66h\r
97d92bda	75	push 0 ; reserved high order 32 bits of EFlags\r
878ddf1f	76	pushf ; pushfd actually\r
97d92bda	77	cli ; disable interrupts\r
878ddf1f	78	push gs\r
	79	push fs\r
	80	DB 6 ; push es\r
	81	DB 1eh ; push ds\r
	82	DB 66h, 60h ; pushad\r
97d92bda	83	DB 66h, 0bah ; mov edx, imm32\r
	84	_ThunkAttr DD ?\r
	85	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
	86	jz @1\r
	87	mov eax, 15cd2401h ; mov ax, 2401h & int 15h\r
	88	cli ; disable interrupts\r
	89	jnc @2\r
	90	@1:\r
	91	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL\r
	92	jz @2\r
	93	in al, 92h\r
	94	or al, 2\r
	95	out 92h, al ; deactivate A20M#\r
	96	@2:\r
	97	mov eax, ss\r
	98	lea bp, [esp + sizeof (IA32_REGS)]\r
	99	mov word ptr (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._ESP, bp\r
	100	mov ebx, (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._EIP\r
	101	shl ax, 4 ; shl eax, 4\r
	102	add bp, ax ; add ebp, eax\r
	103	DB 66h, 0b8h ; mov eax, imm32\r
	104	SavedCr4 DD ?\r
	105	mov cr4, rax\r
	106	DB 66h, 2eh\r
	107	lgdt fword ptr [rdi + (offset SavedGdt - offset @Base)]\r
878ddf1f	108	DB 66h\r
	109	mov ecx, 0c0000080h\r
	110	rdmsr\r
97d92bda	111	or ah, 1\r
878ddf1f	112	wrmsr\r
97d92bda	113	DB 66h, 0b8h ; mov eax, imm32\r
	114	SavedCr0 DD ?\r
	115	mov cr0, rax\r
	116	DB 0b8h ; mov ax, imm16\r
	117	SavedSs DW ?\r
	118	mov ss, eax\r
	119	DB 66h, 0bch ; mov esp, imm32\r
	120	SavedEsp DD ?\r
878ddf1f	121	DB 66h\r
97d92bda	122	retf ; return to protected mode\r
	123	_BackFromUserCode ENDP\r
	124	\r
	125	_EntryPoint DD offset _ToUserCode - offset m16Start\r
	126	DW 8h\r
	127	_16Gdtr LABEL FWORD\r
	128	DW offset GdtEnd - offset _NullSegDesc - 1\r
	129	_16GdtrBase DQ offset _NullSegDesc\r
	130	_16Idtr FWORD (1 SHL 10) - 1\r
	131	\r
	132	_ToUserCode PROC\r
	133	mov edi, ss\r
	134	mov ss, edx ; set new segment selectors\r
	135	mov ds, edx\r
	136	mov es, edx\r
	137	mov fs, edx\r
	138	mov gs, edx\r
878ddf1f	139	DB 66h\r
97d92bda	140	mov ecx, 0c0000080h\r
	141	mov cr0, rax ; real mode starts at next instruction\r
	142	rdmsr\r
	143	and ah, NOT 1\r
	144	wrmsr\r
	145	mov cr4, rbp\r
	146	mov ss, esi ; set up 16-bit stack segment\r
	147	xchg sp, bx ; set up 16-bit stack pointer\r
878ddf1f	148	DB 66h\r
97d92bda	149	call @Base ; push eip\r
	150	@Base:\r
	151	pop bp ; ebp <- offset @Base\r
	152	DB 2eh ; cs:\r
	153	mov [rsi + (offset SavedSs - offset @Base)], edi\r
	154	DB 2eh ; cs:\r
	155	mov [rsi + (offset SavedEsp - offset @Base)], bx\r
	156	DB 66h, 2eh ; CS and operand size override\r
	157	lidt fword ptr [rsi + (offset _16Idtr - offset @Base)]\r
	158	DB 66h, 61h ; popad\r
	159	DB 1fh ; pop ds\r
	160	DB 07h ; pop es\r
	161	pop fs\r
	162	pop gs\r
	163	popf ; popfd\r
	164	lea sp, [esp + 4] ; skip high order 32 bits of EFlags\r
878ddf1f	165	DB 66h\r
97d92bda	166	retf ; transfer control to user code\r
	167	_ToUserCode ENDP\r
	168	\r
	169	_NullSegDesc DQ 0\r
	170	_16CsDesc LABEL QWORD\r
	171	DW -1\r
	172	DW 0\r
	173	DB 0\r
	174	DB 9bh\r
	175	DB 8fh ; 16-bit segment, 4GB limit\r
	176	DB 0\r
	177	_16DsDesc LABEL QWORD\r
	178	DW -1\r
	179	DW 0\r
	180	DB 0\r
	181	DB 93h\r
	182	DB 8fh ; 16-bit segment, 4GB limit\r
	183	DB 0\r
	184	GdtEnd LABEL QWORD\r
	185	\r
	186	;\r
	187	; @param RegSet Pointer to a IA32_DWORD_REGS structure\r
	188	; @param Transition Pointer to the transition code\r
	189	; @return The address of the 16-bit stack after returning from user code\r
	190	;\r
	191	InternalAsmThunk16 PROC USES rbp rbx rsi rdi\r
	192	mov r10d, ds\r
	193	mov r11d, es\r
	194	push fs\r
	195	push gs\r
	196	mov rsi, rcx\r
	197	movzx r8d, (IA32_REGS ptr [rsi])._SS\r
	198	mov edi, (IA32_REGS ptr [rsi])._ESP\r
	199	lea rdi, [edi - (sizeof (IA32_REGS) + 4)]\r
	200	imul eax, r8d, 16 ; eax <- r8d(stack segment) * 16\r
	201	mov ebx, edi ; ebx <- stack offset for 16-bit code\r
	202	push sizeof (IA32_REGS) / 4\r
	203	add edi, eax ; edi <- linear address of 16-bit stack\r
	204	pop rcx\r
	205	rep movsd ; copy RegSet\r
	206	lea ecx, [rdx + (offset SavedCr4 - offset m16Start)]\r
	207	mov eax, edx ; eax <- transition code address\r
	208	and edx, 0fh\r
	209	shl eax, 12\r
	210	lea edx, [rdx + (offset _BackFromUserCode - offset m16Start)]\r
	211	mov ax, dx\r
	212	stosd ; [edi] <- return address of user code\r
	213	sgdt fword ptr [rcx + (offset SavedGdt - offset SavedCr4)]\r
	214	sidt fword ptr [rsp + 38h] ; save IDT stack in argument space\r
	215	mov rax, cr0\r
	216	mov [rcx + (offset SavedCr0 - offset SavedCr4)], eax\r
	217	and eax, 7ffffffeh ; clear PE, PG bits\r
	218	mov rbp, cr4\r
	219	mov [rcx], ebp ; save CR4 in SavedCr4\r
	220	and ebp, 300h ; clear all but PCE and OSFXSR bits\r
	221	mov esi, r8d ; esi <- 16-bit stack segment\r
	222	push 10h\r
	223	pop rdx ; rdx <- selector for data segments\r
	224	lgdt fword ptr [rcx + (offset _16Gdtr - offset SavedCr4)]\r
	225	call fword ptr [rcx + (offset _EntryPoint - offset SavedCr4)]\r
	226	lidt fword ptr [rsp + 38h] ; restore protected mode IDTR\r
	227	lea eax, [rbp - sizeof (IA32_REGS)]\r
878ddf1f	228	pop gs\r
878ddf1f	229	pop fs\r
97d92bda	230	mov es, r11d\r
97d92bda	231	mov ds, r10d\r
878ddf1f	232	ret\r
	233	InternalAsmThunk16 ENDP\r
	234	\r
	235	END\r