[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      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
o32 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      _NullSegDesc\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
6dab5c8a JJ	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 InternalAsmThunk16 - ASM_PFX(m16Start)\r
7458df40	62	ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttrEnd - 4 - ASM_PFX(m16Start)\r
6dab5c8a JJ	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
f6888eea	85	BITS 16\r
6dab5c8a JJ	86	push ss\r
6dab5c8a JJ	87	push cs\r
f6888eea	88	o32 call dword .Base ; push eip\r
a8458d6c	89	.Base:\r
f6888eea	90	pushfd\r
6dab5c8a JJ	91	cli ; disable interrupts\r
	92	push gs\r
	93	push fs\r
	94	push es\r
	95	push ds\r
f6888eea	96	pushad\r
7458df40 JJ	97	mov edx, strict dword 0\r
7458df40 JJ	98	.ThunkAttrEnd:\r
6dab5c8a	99	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
a8458d6c	100	jz .1\r
f6888eea JJ	101	mov ax, 2401h\r
f6888eea JJ	102	int 15h\r
6dab5c8a	103	cli ; disable interrupts\r
a8458d6c JJ	104	jnc .2\r
a8458d6c JJ	105	.1:\r
6dab5c8a	106	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL\r
a8458d6c	107	jz .2\r
6dab5c8a JJ	108	in al, 92h\r
	109	or al, 2\r
	110	out 92h, al ; deactivate A20M#\r
a8458d6c	111	.2:\r
f6888eea JJ	112	xor eax, eax\r
	113	mov ax, ss\r
	114	lea ebp, [esp + IA32_REGS.size]\r
	115	mov [bp - IA32_REGS.size + IA32_REGS._ESP], ebp\r
	116	mov bx, [bp - IA32_REGS.size + IA32_REGS._EIP]\r
	117	shl eax, 4 ; shl eax, 4\r
	118	add ebp, eax ; add ebp, eax\r
7458df40 JJ	119	mov eax, strict dword 0\r
7458df40 JJ	120	.SavedCr4End:\r
6dab5c8a	121	mov cr4, eax\r
f6888eea	122	o32 lgdt [cs:bx + (SavedGdt - .Base)]\r
7458df40 JJ	123	mov eax, strict dword 0\r
7458df40 JJ	124	.SavedCr0End:\r
6dab5c8a	125	mov cr0, eax\r
7458df40 JJ	126	mov ax, strict word 0\r
7458df40 JJ	127	.SavedSsEnd:\r
6dab5c8a	128	mov ss, eax\r
7458df40 JJ	129	mov esp, strict dword 0\r
7458df40 JJ	130	.SavedEspEnd:\r
f6888eea	131	o32 retf ; return to protected mode\r
6dab5c8a JJ	132	\r
	133	_EntryPoint:\r
	134	DD _ToUserCode - ASM_PFX(m16Start)\r
	135	DW 8h\r
	136	_16Idtr:\r
	137	DW (1 << 10) - 1\r
	138	DD 0\r
	139	_16Gdtr:\r
	140	DW GdtEnd - _NullSegDesc - 1\r
	141	_16GdtrBase:\r
	142	DD _NullSegDesc\r
	143	\r
	144	;------------------------------------------------------------------------------\r
	145	; _ToUserCode() takes control in real mode before passing control to user code.\r
	146	; It will be shadowed to somewhere in memory below 1MB.\r
	147	;------------------------------------------------------------------------------\r
	148	_ToUserCode:\r
f6888eea JJ	149	BITS 16\r
	150	mov dx, ss\r
	151	mov ss, cx ; set new segment selectors\r
	152	mov ds, cx\r
	153	mov es, cx\r
	154	mov fs, cx\r
	155	mov gs, cx\r
6dab5c8a JJ	156	mov cr0, eax ; real mode starts at next instruction\r
6dab5c8a JJ	157	; which (per SDM) must be a far JMP.\r
7458df40 JJ	158	jmp 0:strict word 0\r
7458df40 JJ	159	.RealAddrEnd:\r
6dab5c8a	160	mov cr4, ebp\r
f6888eea JJ	161	mov ss, si ; set up 16-bit stack segment\r
	162	xchg esp, ebx ; set up 16-bit stack pointer\r
	163	mov bp, [esp + IA32_REGS.size]\r
7458df40 JJ	164	mov [cs:bp + (_BackFromUserCode.SavedSsEnd - 2 - _BackFromUserCode)], dx\r
7458df40 JJ	165	mov [cs:bp + (_BackFromUserCode.SavedEspEnd - 4 - _BackFromUserCode)], ebx\r
f6888eea JJ	166	lidt [cs:bp + (_16Idtr - _BackFromUserCode)]\r
	167	\r
	168	popad\r
6dab5c8a JJ	169	pop ds\r
	170	pop es\r
	171	pop fs\r
	172	pop gs\r
f6888eea	173	popfd\r
6dab5c8a	174	\r
f6888eea	175	o32 retf ; transfer control to user code\r
6dab5c8a JJ	176	\r
	177	ALIGN 16\r
	178	_NullSegDesc DQ 0\r
	179	_16CsDesc:\r
	180	DW -1\r
	181	DW 0\r
	182	DB 0\r
	183	DB 9bh\r
	184	DB 8fh ; 16-bit segment, 4GB limit\r
	185	DB 0\r
	186	_16DsDesc:\r
	187	DW -1\r
	188	DW 0\r
	189	DB 0\r
	190	DB 93h\r
	191	DB 8fh ; 16-bit segment, 4GB limit\r
	192	DB 0\r
	193	GdtEnd:\r
	194	\r
	195	;------------------------------------------------------------------------------\r
	196	; IA32_REGISTER_SET *\r
	197	; EFIAPI\r
	198	; InternalAsmThunk16 (\r
	199	; IN IA32_REGISTER_SET *RegisterSet,\r
	200	; IN OUT VOID *Transition\r
	201	; );\r
	202	;------------------------------------------------------------------------------\r
	203	global ASM_PFX(InternalAsmThunk16)\r
	204	ASM_PFX(InternalAsmThunk16):\r
f6888eea	205	BITS 32\r
6dab5c8a JJ	206	push ebp\r
	207	push ebx\r
	208	push esi\r
	209	push edi\r
	210	push ds\r
	211	push es\r
	212	push fs\r
	213	push gs\r
	214	mov esi, [esp + 36] ; esi <- RegSet, the 1st parameter\r
	215	movzx edx, word [esi + IA32_REGS._SS]\r
	216	mov edi, [esi + IA32_REGS._ESP]\r
	217	add edi, - (IA32_REGS.size + 4) ; reserve stack space\r
	218	mov ebx, edi ; ebx <- stack offset\r
	219	imul eax, edx, 16 ; eax <- edx * 16\r
	220	push IA32_REGS.size / 4\r
	221	add edi, eax ; edi <- linear address of 16-bit stack\r
	222	pop ecx\r
	223	rep movsd ; copy RegSet\r
	224	mov eax, [esp + 40] ; eax <- address of transition code\r
	225	mov esi, edx ; esi <- 16-bit stack segment\r
7458df40	226	lea edx, [eax + (_BackFromUserCode.SavedCr0End - ASM_PFX(m16Start))]\r
6dab5c8a JJ	227	mov ecx, eax\r
	228	and ecx, 0fh\r
	229	shl eax, 12\r
	230	lea ecx, [ecx + (_BackFromUserCode - ASM_PFX(m16Start))]\r
	231	mov ax, cx\r
	232	stosd ; [edi] <- return address of user code\r
7458df40 JJ	233	add eax, _ToUserCode.RealAddrEnd - _BackFromUserCode\r
	234	mov [edx + (_ToUserCode.RealAddrEnd - 4 - _BackFromUserCode.SavedCr0End)], eax\r
	235	sgdt [edx + (SavedGdt - _BackFromUserCode.SavedCr0End)]\r
6dab5c8a JJ	236	sidt [esp + 36] ; save IDT stack in argument space\r
6dab5c8a JJ	237	mov eax, cr0\r
7458df40	238	mov [edx - 4], eax ; save CR0 in _BackFromUserCode.SavedCr0End - 4\r
6dab5c8a JJ	239	and eax, 7ffffffeh ; clear PE, PG bits\r
6dab5c8a JJ	240	mov ebp, cr4\r
7458df40	241	mov [edx + (_BackFromUserCode.SavedCr4End - 4 - _BackFromUserCode.SavedCr0End)], ebp\r
6dab5c8a JJ	242	and ebp, ~30h ; clear PAE, PSE bits\r
	243	push 10h\r
	244	pop ecx ; ecx <- selector for data segments\r
7458df40	245	lgdt [edx + (_16Gdtr - _BackFromUserCode.SavedCr0End)]\r
6dab5c8a	246	pushfd ; Save df/if indeed\r
7458df40	247	call dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0End)]\r
6dab5c8a JJ	248	popfd\r
	249	lidt [esp + 36] ; restore protected mode IDTR\r
	250	lea eax, [ebp - IA32_REGS.size] ; eax <- the address of IA32_REGS\r
	251	pop gs\r
	252	pop fs\r
	253	pop es\r
	254	pop ds\r
	255	pop edi\r
	256	pop esi\r
	257	pop ebx\r
	258	pop ebp\r
	259	ret\r