bs3-cpu-state64-1-asm.asm@ 93115

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1	; $Id: bs3-cpu-state64-1-asm.asm 93115 2022-01-01 11:31:46Z vboxsync $
2	;; @file
3	; BS3Kit - bs3-cpu-state64-1
4	;
5
6	;
7	; Copyright (C) 2007-2022 Oracle Corporation
8	;
9	; This file is part of VirtualBox Open Source Edition (OSE), as
10	; available from http://www.virtualbox.org. This file is free software;
11	; you can redistribute it and/or modify it under the terms of the GNU
12	; General Public License (GPL) as published by the Free Software
13	; Foundation, in version 2 as it comes in the "COPYING" file of the
14	; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	;
17	; The contents of this file may alternatively be used under the terms
18	; of the Common Development and Distribution License Version 1.0
19	; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	; VirtualBox OSE distribution, in which case the provisions of the
21	; CDDL are applicable instead of those of the GPL.
22	;
23	; You may elect to license modified versions of this file under the
24	; terms and conditions of either the GPL or the CDDL or both.
25	;
26
27
28	;*********************************************************************************************************************************
29	;* Header Files *
30	;*********************************************************************************************************************************
31	%include "bs3kit.mac"
32
33
34	;*********************************************************************************************************************************
35	;* Global Variables *
36	;*********************************************************************************************************************************
37	BS3_BEGIN_DATA16
38	BS3_GLOBAL_DATA g_bs3CpuState64CtxCaller, BS3REGCTX_size
39	resb BS3REGCTX_size
40	BS3_GLOBAL_DATA g_bs3CpuState64CtxToLoad, BS3REGCTX_size
41	resb BS3REGCTX_size
42	BS3_GLOBAL_DATA g_bs3CpuState64CtxSaved, BS3REGCTX_size
43	resb BS3REGCTX_size
44
45	BS3_GLOBAL_DATA g_bs3CpuState64RCX, 8
46	dq 1
47
48
49	;*********************************************************************************************************************************
50	;* External Symbols *
51	;*********************************************************************************************************************************
52	BS3_BEGIN_TEXT64
53	EXTERN Bs3RegCtxRestore_c64
54	EXTERN Bs3RegCtxSave_c64
55
56
57	BS3_BEGIN_TEXT64
58	BS3_SET_BITS 64
59
60	;;
61	;; Test worker that switches between 64-bit and 16-bit real mode,
62	;; only trashing RAX, BX, DS, RSP (preseved) and RIP.
63	;;
64	;; Caller puts the state to load in g_bs3CpuState64CtxToLoad, this function alters
65	;; the BX and RIP values before loading it. It then switches to 16-bit real mode,
66	;; executes the worker given as input, re-enters long mode and saves the state to
67	;; g_bs3CpuState64CtxSaved.
68	;;
69	;; @param rcx Address of worker (16-bit) to invoke while in real-mode.
70	;;
71	BS3_PROC_BEGIN NAME(bs3CpuState64Worker)
72	push rbp
73	mov rbp, rsp
74	sub rsp, 40h
75	mov [rbp + 16], rcx
76
77	;
78	; Save the current register state so we can return with the exact state we entered.
79	;
80	lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxCaller)) wrt FLAT]
81	mov [rsp], rcx
82	call NAME(Bs3RegCtxSave_c64)
83
84	;
85	; Load the context. We modify the state to be loaded so that it fits
86	; into the code flow here..
87	;
88	lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxToLoad)) wrt FLAT]
89	mov [rcx + BS3REGCTX.rsp], rsp
90	;lea rdx, [BS3_WRT_RIP(.ctx_loaded) wrt FLAT] - absolute address cannot be relative. wtf?
91	mov edx, .ctx_loaded wrt FLAT
92	mov [rcx + BS3REGCTX.rip], rdx
93	mov edx, [rbp + 16] ; Worker address. Putting it in the BX register relative to 16-bit CS.
94	sub edx, BS3_ADDR_BS3TEXT16
95	mov [rcx + BS3REGCTX.rbx], dx
96	mov edx, 0 ; fFlags
97	mov [rsp], rcx
98	mov [rsp + 8], rdx
99	call NAME(Bs3RegCtxRestore_c64)
100	.ctx_loaded:
101
102	;
103	; Disable long mode.
104	;
105
106	; Construct a far return for switching to 16-bit code.
107	push BS3_SEL_R0_CS16
108	push .sixteen_bit_segment wrt CGROUP16
109	xRETF
110	BS3_BEGIN_TEXT16
111	BS3_SET_BITS 16
112	BS3_GLOBAL_LOCAL_LABEL .sixteen_bit_segment
113	; Make the DS usable from real mode.
114	mov ax, BS3_SEL_R0_DS16
115	mov ds, ax
116
117	; Exit to real mode.
118	mov eax, cr0
119	and eax, X86_CR0_NO_PE_NO_PG
120	mov cr0, eax
121	jmp CGROUP16:.reload_cs16
122	BS3_GLOBAL_LOCAL_LABEL .reload_cs16
123
124	;
125	; Jump to the 16-bit worker function that will make state modifications.
126	;
127	jmp bx
128	BS3_GLOBAL_LOCAL_LABEL .resume16
129
130	;
131	; Re-enter long mode.
132	;
133	mov eax, cr0
134	or eax, X86_CR0_PE \| X86_CR0_PG
135	mov cr0, eax
136	jmp CGROUP16:.reload_cs_long_mode
137	BS3_GLOBAL_LOCAL_LABEL .reload_cs_long_mode
138	; Construct a far return for switching to 64-bit code.
139	push dword BS3_SEL_R0_CS64
140	push dword .sixtyfour_bit_segment wrt FLAT
141	o32 retf
142	BS3_BEGIN_TEXT64
143	BS3_GLOBAL_LOCAL_LABEL .sixtyfour_bit_segment
144	BS3_SET_BITS 64
145
146	;
147	; We're back in long mode, save the context.
148	;
149	mov [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64RCX)) wrt FLAT], rcx
150	lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxSaved)) wrt FLAT]
151	mov [rsp], rcx
152	call NAME(Bs3RegCtxSave_c64)
153	lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxSaved)) wrt FLAT]
154	mov rax, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64RCX)) wrt FLAT]
155	mov [rcx + BS3REGCTX.rcx], rax
156
157	;
158	; Load the caller's context.
159	;
160	lea rcx, [BS3_WRT_RIP(BS3_DATA_NM(g_bs3CpuState64CtxCaller)) wrt FLAT]
161	;lea rdx, [BS3_WRT_RIP(.return_sequence) wrt FLAT] - absolute address cannot be relative. wtf?
162	mov edx, .return_sequence wrt FLAT
163	mov [rcx + BS3REGCTX.rip], rdx
164	mov edx, 0
165	mov [rsp], rcx
166	mov [rsp + 8], rdx
167	call NAME(Bs3RegCtxRestore_c64)
168	.return_sequence:
169
170	add rsp, 40h
171	pop rbp
172	ret
173	BS3_PROC_END NAME(bs3CpuState64Worker)
174
175
176	BS3_BEGIN_TEXT16
177	;
178	; Real-mod modification workers for bs3CpuState64Worker.
179	;
180
181	BS3_PROC_BEGIN NAME(bs3CpuState64Worker_Nop)
182	nop
183	jmp NAME(bs3CpuState64Worker.resume16)
184	BS3_PROC_END NAME(bs3CpuState64Worker_Nop)
185
186
187	BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModAll32BitGrps)
188	mov eax, 0xc0ffee0d ; C code hardcodes these values too.
189	mov ecx, 0xc0ffee1d
190	mov edx, 0xc0ffee2d
191	mov ebx, 0xc0ffee3d
192	; leave esp alone for now.
193	mov ebp, 0xc0ffee5d
194	mov esi, 0xc0ffee6d
195	mov edi, 0xc0ffee7d
196	jmp NAME(bs3CpuState64Worker.resume16)
197	BS3_PROC_END NAME(bs3CpuState64Worker_ModAll32BitGrps)
198
199
200	BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModAll16BitGrps)
201	mov ax, 0xfad0 ; C code hardcodes these values too.
202	mov cx, 0xfad1
203	mov dx, 0xfad2
204	mov bx, 0xfad3
205	; leave esp alone for now.
206	mov bp, 0xfad5
207	mov si, 0xfad6
208	mov di, 0xfad7
209	jmp NAME(bs3CpuState64Worker.resume16)
210	BS3_PROC_END NAME(bs3CpuState64Worker_ModAll16BitGrps)
211
212
213	BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModAll8BitGrps)
214	mov al, 0x10 ; C code hardcodes these values too.
215	mov ah, 0x11
216	mov cl, 0x20
217	mov ch, 0x21
218	mov dl, 0x30
219	mov dh, 0x31
220	mov bl, 0x40
221	mov bh, 0x41
222	jmp NAME(bs3CpuState64Worker.resume16)
223	BS3_PROC_END NAME(bs3CpuState64Worker_ModAll8BitGrps)
224
225	BS3_PROC_BEGIN NAME(bs3CpuState64Worker_ModCr2)
226	mov eax, 0xf00dface ; C code hardcodes this value too.
227	mov cr2, eax
228	jmp NAME(bs3CpuState64Worker.resume16)
229	BS3_PROC_END NAME(bs3CpuState64Worker_ModCr2)
230
231	;; @todo drX registers.
232

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source: vbox/trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-state64-1-asm.asm@ 93115

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