[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / Thunk16.nasm

\r
#include "BaseLibInternals.h"\r
\r
;------------------------------------------------------------------------------\r
;\r
; Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>\r
; 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
global ASM_PFX(m16Size)\r
global ASM_PFX(mThunk16Attr)\r
global ASM_PFX(m16Gdt)\r
global ASM_PFX(m16GdtrBase)\r
global ASM_PFX(mTransition)\r
global ASM_PFX(m16Start)\r
\r
struc IA32_REGS\r
\r
  ._EDI:       resd      1\r
  ._ESI:       resd      1\r
  ._EBP:       resd      1\r
  ._ESP:       resd      1\r
  ._EBX:       resd      1\r
  ._EDX:       resd      1\r
  ._ECX:       resd      1\r
  ._EAX:       resd      1\r
  ._DS:        resw      1\r
  ._ES:        resw      1\r
  ._FS:        resw      1\r
  ._GS:        resw      1\r
  ._EFLAGS:    resd      1\r
  ._EIP:       resd      1\r
  ._CS:        resw      1\r
  ._SS:        resw      1\r
  .size:\r
\r
endstruc\r
\r
;; .const\r
\r
SECTION .data\r
\r
;\r
; These are global constant to convey information to C code.\r
;\r
ASM_PFX(m16Size)         DW      ASM_PFX(InternalAsmThunk16) - ASM_PFX(m16Start)\r
ASM_PFX(mThunk16Attr)    DW      _BackFromUserCode.ThunkAttrEnd - 4 - ASM_PFX(m16Start)\r
ASM_PFX(m16Gdt)          DW      _NullSegDesc - ASM_PFX(m16Start)\r
ASM_PFX(m16GdtrBase)     DW      _16GdtrBase - ASM_PFX(m16Start)\r
ASM_PFX(mTransition)     DW      _EntryPoint - ASM_PFX(m16Start)\r
\r
SECTION .text\r
\r
ASM_PFX(m16Start):\r
\r
SavedGdt:\r
            dw  0\r
            dd  0\r
\r
;------------------------------------------------------------------------------\r
; _BackFromUserCode() takes control in real mode after 'retf' has been executed\r
; by user code. It will be shadowed to somewhere in memory below 1MB.\r
;------------------------------------------------------------------------------\r
_BackFromUserCode:\r
    ;\r
    ; The order of saved registers on the stack matches the order they appears\r
    ; in IA32_REGS structure. This facilitates wrapper function to extract them\r
    ; into that structure.\r
    ;\r
BITS    16\r
    push    ss\r
    push    cs\r
    ;\r
    ; Note: We can't use o32 on the next instruction because of a bug\r
    ; in NASM 2.09.04 through 2.10rc1.\r
    ;\r
    call    dword .Base                 ; push eip\r
.Base:\r
    pushfd\r
    cli                                 ; disable interrupts\r
    push    gs\r
    push    fs\r
    push    es\r
    push    ds\r
    pushad\r
    mov     edx, strict dword 0\r
.ThunkAttrEnd:\r
    test    dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
    jz      .1\r
    mov     ax, 2401h\r
    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
    xor     eax, eax\r
    mov     ax, ss\r
    lea     ebp, [esp + IA32_REGS.size]\r
    mov     [bp - IA32_REGS.size + IA32_REGS._ESP], ebp\r
    mov     bx, [bp - IA32_REGS.size + IA32_REGS._EIP]\r
    shl     eax, 4                      ; shl eax, 4\r
    add     ebp, eax                    ; add ebp, eax\r
    mov     eax, strict dword 0\r
.SavedCr4End:\r
    mov     cr4, eax\r
o32 lgdt [cs:bx + (SavedGdt - .Base)]\r
    mov     eax, strict dword 0\r
.SavedCr0End:\r
    mov     cr0, eax\r
    mov     ax, strict word 0\r
.SavedSsEnd:\r
    mov     ss, eax\r
    mov     esp, strict dword 0\r
.SavedEspEnd:\r
o32 retf                                ; return to protected mode\r
\r
_EntryPoint:\r
        DD      _ToUserCode - ASM_PFX(m16Start)\r
        DW      8h\r
_16Idtr:\r
        DW      (1 << 10) - 1\r
        DD      0\r
_16Gdtr:\r
        DW      GdtEnd - _NullSegDesc - 1\r
_16GdtrBase:\r
        DD      0\r
\r
;------------------------------------------------------------------------------\r
; _ToUserCode() takes control in real mode before passing control to user code.\r
; It will be shadowed to somewhere in memory below 1MB.\r
;------------------------------------------------------------------------------\r
_ToUserCode:\r
BITS    16\r
    mov     dx, ss\r
    mov     ss, cx                      ; set new segment selectors\r
    mov     ds, cx\r
    mov     es, cx\r
    mov     fs, cx\r
    mov     gs, cx\r
    mov     cr0, eax                    ; real mode starts at next instruction\r
                                        ;  which (per SDM) *must* be a far JMP.\r
    jmp     0:strict word 0\r
.RealAddrEnd:\r
    mov     cr4, ebp\r
    mov     ss, si                      ; set up 16-bit stack segment\r
    xchg    esp, ebx                    ; set up 16-bit stack pointer\r
    mov     bp, [esp + IA32_REGS.size]\r
    mov     [cs:bp + (_BackFromUserCode.SavedSsEnd - 2 - _BackFromUserCode)], dx\r
    mov     [cs:bp + (_BackFromUserCode.SavedEspEnd - 4 - _BackFromUserCode)], ebx\r
    lidt    [cs:bp + (_16Idtr - _BackFromUserCode)]\r
\r
    popad\r
    pop     ds\r
    pop     es\r
    pop     fs\r
    pop     gs\r
    popfd\r
\r
o32 retf                                ; transfer control to user code\r
\r
ALIGN   16\r
_NullSegDesc    DQ      0\r
_16CsDesc:\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:\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:\r
\r
;------------------------------------------------------------------------------\r
; IA32_REGISTER_SET *\r
; EFIAPI\r
; InternalAsmThunk16 (\r
;   IN      IA32_REGISTER_SET         *RegisterSet,\r
;   IN OUT  VOID                      *Transition\r
;   );\r
;------------------------------------------------------------------------------\r
global ASM_PFX(InternalAsmThunk16)\r
ASM_PFX(InternalAsmThunk16):\r
BITS    32\r
    push    ebp\r
    push    ebx\r
    push    esi\r
    push    edi\r
    push    ds\r
    push    es\r
    push    fs\r
    push    gs\r
    mov     esi, [esp + 36]             ; esi <- RegSet, the 1st parameter\r
    movzx   edx, word [esi + IA32_REGS._SS]\r
    mov     edi, [esi + IA32_REGS._ESP]\r
    add     edi, - (IA32_REGS.size + 4) ; reserve stack space\r
    mov     ebx, edi                    ; ebx <- stack offset\r
    imul    eax, edx, 16                ; eax <- edx * 16\r
    push    IA32_REGS.size / 4\r
    add     edi, eax                    ; edi <- linear address of 16-bit stack\r
    pop     ecx\r
    rep     movsd                       ; copy RegSet\r
    mov     eax, [esp + 40]             ; eax <- address of transition code\r
    mov     esi, edx                    ; esi <- 16-bit stack segment\r
    lea     edx, [eax + (_BackFromUserCode.SavedCr0End - ASM_PFX(m16Start))]\r
    mov     ecx, eax\r
    and     ecx, 0fh\r
    shl     eax, 12\r
    lea     ecx, [ecx + (_BackFromUserCode - ASM_PFX(m16Start))]\r
    mov     ax, cx\r
    stosd                               ; [edi] <- return address of user code\r
    add     eax, _ToUserCode.RealAddrEnd - _BackFromUserCode\r
    mov     [edx + (_ToUserCode.RealAddrEnd - 4 - _BackFromUserCode.SavedCr0End)], eax\r
    sgdt    [edx + (SavedGdt - _BackFromUserCode.SavedCr0End)]\r
    sidt    [esp + 36]        ; save IDT stack in argument space\r
    mov     eax, cr0\r
    mov     [edx - 4], eax                  ; save CR0 in _BackFromUserCode.SavedCr0End - 4\r
    and     eax, 7ffffffeh              ; clear PE, PG bits\r
    mov     ebp, cr4\r
    mov     [edx + (_BackFromUserCode.SavedCr4End - 4 - _BackFromUserCode.SavedCr0End)], ebp\r
    and     ebp, ~30h                ; clear PAE, PSE bits\r
    push    10h\r
    pop     ecx                         ; ecx <- selector for data segments\r
    lgdt    [edx + (_16Gdtr - _BackFromUserCode.SavedCr0End)]\r
    pushfd                              ; Save df/if indeed\r
    call    dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0End)]\r
    popfd\r
    lidt    [esp + 36]        ; restore protected mode IDTR\r
    lea     eax, [ebp - IA32_REGS.size] ; eax <- the address of IA32_REGS\r
    pop     gs\r
    pop     fs\r
    pop     es\r
    pop     ds\r
    pop     edi\r
    pop     esi\r
    pop     ebx\r
    pop     ebp\r
    ret\r
Commit	Line	Data
	1	\r
	2	#include "BaseLibInternals.h"\r
	3	\r
	4	;------------------------------------------------------------------------------\r
	5	;\r
	6	; Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>\r
	7	; This program and the accompanying materials\r
	8	; are licensed and made available under the terms and conditions of the BSD License\r
	9	; which accompanies this distribution. The full text of the license may be found at\r
	10	; http://opensource.org/licenses/bsd-license.php.\r
	11	;\r
	12	; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	13	; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	14	;\r
	15	; Module Name:\r
	16	;\r
	17	; Thunk.asm\r
	18	;\r
	19	; Abstract:\r
	20	;\r
	21	; Real mode thunk\r
	22	;\r
	23	;------------------------------------------------------------------------------\r
	24	\r
	25	global ASM_PFX(m16Size)\r
	26	global ASM_PFX(mThunk16Attr)\r
	27	global ASM_PFX(m16Gdt)\r
	28	global ASM_PFX(m16GdtrBase)\r
	29	global ASM_PFX(mTransition)\r
	30	global ASM_PFX(m16Start)\r
	31	\r
	32	struc IA32_REGS\r
	33	\r
	34	._EDI: resd 1\r
	35	._ESI: resd 1\r
	36	._EBP: resd 1\r
	37	._ESP: resd 1\r
	38	._EBX: resd 1\r
	39	._EDX: resd 1\r
	40	._ECX: resd 1\r
	41	._EAX: resd 1\r
	42	._DS: resw 1\r
	43	._ES: resw 1\r
	44	._FS: resw 1\r
	45	._GS: resw 1\r
	46	._EFLAGS: resd 1\r
	47	._EIP: resd 1\r
	48	._CS: resw 1\r
	49	._SS: resw 1\r
	50	.size:\r
	51	\r
	52	endstruc\r
	53	\r
	54	;; .const\r
	55	\r
	56	SECTION .data\r
	57	\r
	58	;\r
	59	; These are global constant to convey information to C code.\r
	60	;\r
	61	ASM_PFX(m16Size) DW ASM_PFX(InternalAsmThunk16) - ASM_PFX(m16Start)\r
	62	ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttrEnd - 4 - ASM_PFX(m16Start)\r
	63	ASM_PFX(m16Gdt) DW _NullSegDesc - ASM_PFX(m16Start)\r
	64	ASM_PFX(m16GdtrBase) DW _16GdtrBase - ASM_PFX(m16Start)\r
	65	ASM_PFX(mTransition) DW _EntryPoint - ASM_PFX(m16Start)\r
	66	\r
	67	SECTION .text\r
	68	\r
	69	ASM_PFX(m16Start):\r
	70	\r
	71	SavedGdt:\r
	72	dw 0\r
	73	dd 0\r
	74	\r
	75	;------------------------------------------------------------------------------\r
	76	; _BackFromUserCode() takes control in real mode after 'retf' has been executed\r
	77	; by user code. It will be shadowed to somewhere in memory below 1MB.\r
	78	;------------------------------------------------------------------------------\r
	79	_BackFromUserCode:\r
	80	;\r
	81	; The order of saved registers on the stack matches the order they appears\r
	82	; in IA32_REGS structure. This facilitates wrapper function to extract them\r
	83	; into that structure.\r
	84	;\r
	85	BITS 16\r
	86	push ss\r
	87	push cs\r
	88	;\r
	89	; Note: We can't use o32 on the next instruction because of a bug\r
	90	; in NASM 2.09.04 through 2.10rc1.\r
	91	;\r
	92	call dword .Base ; push eip\r
	93	.Base:\r
	94	pushfd\r
	95	cli ; disable interrupts\r
	96	push gs\r
	97	push fs\r
	98	push es\r
	99	push ds\r
	100	pushad\r
	101	mov edx, strict dword 0\r
	102	.ThunkAttrEnd:\r
	103	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
	104	jz .1\r
	105	mov ax, 2401h\r
	106	int 15h\r
	107	cli ; disable interrupts\r
	108	jnc .2\r
	109	.1:\r
	110	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL\r
	111	jz .2\r
	112	in al, 92h\r
	113	or al, 2\r
	114	out 92h, al ; deactivate A20M#\r
	115	.2:\r
	116	xor eax, eax\r
	117	mov ax, ss\r
	118	lea ebp, [esp + IA32_REGS.size]\r
	119	mov [bp - IA32_REGS.size + IA32_REGS._ESP], ebp\r
	120	mov bx, [bp - IA32_REGS.size + IA32_REGS._EIP]\r
	121	shl eax, 4 ; shl eax, 4\r
	122	add ebp, eax ; add ebp, eax\r
	123	mov eax, strict dword 0\r
	124	.SavedCr4End:\r
	125	mov cr4, eax\r
	126	o32 lgdt [cs:bx + (SavedGdt - .Base)]\r
	127	mov eax, strict dword 0\r
	128	.SavedCr0End:\r
	129	mov cr0, eax\r
	130	mov ax, strict word 0\r
	131	.SavedSsEnd:\r
	132	mov ss, eax\r
	133	mov esp, strict dword 0\r
	134	.SavedEspEnd:\r
	135	o32 retf ; return to protected mode\r
	136	\r
	137	_EntryPoint:\r
	138	DD _ToUserCode - ASM_PFX(m16Start)\r
	139	DW 8h\r
	140	_16Idtr:\r
	141	DW (1 << 10) - 1\r
	142	DD 0\r
	143	_16Gdtr:\r
	144	DW GdtEnd - _NullSegDesc - 1\r
	145	_16GdtrBase:\r
	146	DD 0\r
	147	\r
	148	;------------------------------------------------------------------------------\r
	149	; _ToUserCode() takes control in real mode before passing control to user code.\r
	150	; It will be shadowed to somewhere in memory below 1MB.\r
	151	;------------------------------------------------------------------------------\r
	152	_ToUserCode:\r
	153	BITS 16\r
	154	mov dx, ss\r
	155	mov ss, cx ; set new segment selectors\r
	156	mov ds, cx\r
	157	mov es, cx\r
	158	mov fs, cx\r
	159	mov gs, cx\r
	160	mov cr0, eax ; real mode starts at next instruction\r
	161	; which (per SDM) must be a far JMP.\r
	162	jmp 0:strict word 0\r
	163	.RealAddrEnd:\r
	164	mov cr4, ebp\r
	165	mov ss, si ; set up 16-bit stack segment\r
	166	xchg esp, ebx ; set up 16-bit stack pointer\r
	167	mov bp, [esp + IA32_REGS.size]\r
	168	mov [cs:bp + (_BackFromUserCode.SavedSsEnd - 2 - _BackFromUserCode)], dx\r
	169	mov [cs:bp + (_BackFromUserCode.SavedEspEnd - 4 - _BackFromUserCode)], ebx\r
	170	lidt [cs:bp + (_16Idtr - _BackFromUserCode)]\r
	171	\r
	172	popad\r
	173	pop ds\r
	174	pop es\r
	175	pop fs\r
	176	pop gs\r
	177	popfd\r
	178	\r
	179	o32 retf ; transfer control to user code\r
	180	\r
	181	ALIGN 16\r
	182	_NullSegDesc DQ 0\r
	183	_16CsDesc:\r
	184	DW -1\r
	185	DW 0\r
	186	DB 0\r
	187	DB 9bh\r
	188	DB 8fh ; 16-bit segment, 4GB limit\r
	189	DB 0\r
	190	_16DsDesc:\r
	191	DW -1\r
	192	DW 0\r
	193	DB 0\r
	194	DB 93h\r
	195	DB 8fh ; 16-bit segment, 4GB limit\r
	196	DB 0\r
	197	GdtEnd:\r
	198	\r
	199	;------------------------------------------------------------------------------\r
	200	; IA32_REGISTER_SET *\r
	201	; EFIAPI\r
	202	; InternalAsmThunk16 (\r
	203	; IN IA32_REGISTER_SET *RegisterSet,\r
	204	; IN OUT VOID *Transition\r
	205	; );\r
	206	;------------------------------------------------------------------------------\r
	207	global ASM_PFX(InternalAsmThunk16)\r
	208	ASM_PFX(InternalAsmThunk16):\r
	209	BITS 32\r
	210	push ebp\r
	211	push ebx\r
	212	push esi\r
	213	push edi\r
	214	push ds\r
	215	push es\r
	216	push fs\r
	217	push gs\r
	218	mov esi, [esp + 36] ; esi <- RegSet, the 1st parameter\r
	219	movzx edx, word [esi + IA32_REGS._SS]\r
	220	mov edi, [esi + IA32_REGS._ESP]\r
	221	add edi, - (IA32_REGS.size + 4) ; reserve stack space\r
	222	mov ebx, edi ; ebx <- stack offset\r
	223	imul eax, edx, 16 ; eax <- edx * 16\r
	224	push IA32_REGS.size / 4\r
	225	add edi, eax ; edi <- linear address of 16-bit stack\r
	226	pop ecx\r
	227	rep movsd ; copy RegSet\r
	228	mov eax, [esp + 40] ; eax <- address of transition code\r
	229	mov esi, edx ; esi <- 16-bit stack segment\r
	230	lea edx, [eax + (_BackFromUserCode.SavedCr0End - ASM_PFX(m16Start))]\r
	231	mov ecx, eax\r
	232	and ecx, 0fh\r
	233	shl eax, 12\r
	234	lea ecx, [ecx + (_BackFromUserCode - ASM_PFX(m16Start))]\r
	235	mov ax, cx\r
	236	stosd ; [edi] <- return address of user code\r
	237	add eax, _ToUserCode.RealAddrEnd - _BackFromUserCode\r
	238	mov [edx + (_ToUserCode.RealAddrEnd - 4 - _BackFromUserCode.SavedCr0End)], eax\r
	239	sgdt [edx + (SavedGdt - _BackFromUserCode.SavedCr0End)]\r
	240	sidt [esp + 36] ; save IDT stack in argument space\r
	241	mov eax, cr0\r
	242	mov [edx - 4], eax ; save CR0 in _BackFromUserCode.SavedCr0End - 4\r
	243	and eax, 7ffffffeh ; clear PE, PG bits\r
	244	mov ebp, cr4\r
	245	mov [edx + (_BackFromUserCode.SavedCr4End - 4 - _BackFromUserCode.SavedCr0End)], ebp\r
	246	and ebp, ~30h ; clear PAE, PSE bits\r
	247	push 10h\r
	248	pop ecx ; ecx <- selector for data segments\r
	249	lgdt [edx + (_16Gdtr - _BackFromUserCode.SavedCr0End)]\r
	250	pushfd ; Save df/if indeed\r
	251	call dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0End)]\r
	252	popfd\r
	253	lidt [esp + 36] ; restore protected mode IDTR\r
	254	lea eax, [ebp - IA32_REGS.size] ; eax <- the address of IA32_REGS\r
	255	pop gs\r
	256	pop fs\r
	257	pop es\r
	258	pop ds\r
	259	pop edi\r
	260	pop esi\r
	261	pop ebx\r
	262	pop ebp\r
	263	ret\r