[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
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
15f8eef7	61	ASM_PFX(m16Size) DW ASM_PFX(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
eabcdf3a JJ	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
a8458d6c	93	.Base:\r
f6888eea	94	pushfd\r
6dab5c8a JJ	95	cli ; disable interrupts\r
	96	push gs\r
	97	push fs\r
	98	push es\r
	99	push ds\r
f6888eea	100	pushad\r
7458df40 JJ	101	mov edx, strict dword 0\r
7458df40 JJ	102	.ThunkAttrEnd:\r
6dab5c8a	103	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15\r
a8458d6c	104	jz .1\r
f6888eea JJ	105	mov ax, 2401h\r
f6888eea JJ	106	int 15h\r
6dab5c8a	107	cli ; disable interrupts\r
a8458d6c JJ	108	jnc .2\r
a8458d6c JJ	109	.1:\r
6dab5c8a	110	test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL\r
a8458d6c	111	jz .2\r
6dab5c8a JJ	112	in al, 92h\r
	113	or al, 2\r
	114	out 92h, al ; deactivate A20M#\r
a8458d6c	115	.2:\r
f6888eea JJ	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
7458df40 JJ	123	mov eax, strict dword 0\r
7458df40 JJ	124	.SavedCr4End:\r
6dab5c8a	125	mov cr4, eax\r
f6888eea	126	o32 lgdt [cs:bx + (SavedGdt - .Base)]\r
7458df40 JJ	127	mov eax, strict dword 0\r
7458df40 JJ	128	.SavedCr0End:\r
6dab5c8a	129	mov cr0, eax\r
7458df40 JJ	130	mov ax, strict word 0\r
7458df40 JJ	131	.SavedSsEnd:\r
6dab5c8a	132	mov ss, eax\r
7458df40 JJ	133	mov esp, strict dword 0\r
7458df40 JJ	134	.SavedEspEnd:\r
f6888eea	135	o32 retf ; return to protected mode\r
6dab5c8a JJ	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
03e9db15	146	DD 0\r
6dab5c8a JJ	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
f6888eea JJ	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
6dab5c8a JJ	160	mov cr0, eax ; real mode starts at next instruction\r
6dab5c8a JJ	161	; which (per SDM) must be a far JMP.\r
7458df40 JJ	162	jmp 0:strict word 0\r
7458df40 JJ	163	.RealAddrEnd:\r
6dab5c8a	164	mov cr4, ebp\r
f6888eea JJ	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
7458df40 JJ	168	mov [cs:bp + (_BackFromUserCode.SavedSsEnd - 2 - _BackFromUserCode)], dx\r
7458df40 JJ	169	mov [cs:bp + (_BackFromUserCode.SavedEspEnd - 4 - _BackFromUserCode)], ebx\r
f6888eea JJ	170	lidt [cs:bp + (_16Idtr - _BackFromUserCode)]\r
	171	\r
	172	popad\r
6dab5c8a JJ	173	pop ds\r
	174	pop es\r
	175	pop fs\r
	176	pop gs\r
f6888eea	177	popfd\r
6dab5c8a	178	\r
f6888eea	179	o32 retf ; transfer control to user code\r
6dab5c8a JJ	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
f6888eea	209	BITS 32\r
6dab5c8a JJ	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
7458df40	230	lea edx, [eax + (_BackFromUserCode.SavedCr0End - ASM_PFX(m16Start))]\r
6dab5c8a JJ	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
7458df40 JJ	237	add eax, _ToUserCode.RealAddrEnd - _BackFromUserCode\r
	238	mov [edx + (_ToUserCode.RealAddrEnd - 4 - _BackFromUserCode.SavedCr0End)], eax\r
	239	sgdt [edx + (SavedGdt - _BackFromUserCode.SavedCr0End)]\r
6dab5c8a JJ	240	sidt [esp + 36] ; save IDT stack in argument space\r
6dab5c8a JJ	241	mov eax, cr0\r
7458df40	242	mov [edx - 4], eax ; save CR0 in _BackFromUserCode.SavedCr0End - 4\r
6dab5c8a JJ	243	and eax, 7ffffffeh ; clear PE, PG bits\r
6dab5c8a JJ	244	mov ebp, cr4\r
7458df40	245	mov [edx + (_BackFromUserCode.SavedCr4End - 4 - _BackFromUserCode.SavedCr0End)], ebp\r
6dab5c8a JJ	246	and ebp, ~30h ; clear PAE, PSE bits\r
	247	push 10h\r
	248	pop ecx ; ecx <- selector for data segments\r
7458df40	249	lgdt [edx + (_16Gdtr - _BackFromUserCode.SavedCr0End)]\r
6dab5c8a	250	pushfd ; Save df/if indeed\r
7458df40	251	call dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0End)]\r
6dab5c8a JJ	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