bs3-c16-Trap16Generic.asm@ 66316

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1	; $Id: bs3-c16-Trap16Generic.asm 64529 2016-11-03 14:01:30Z vboxsync $
2	;; @file
3	; BS3Kit - Trap, 16-bit assembly handlers.
4	;
5
6	;
7	; Copyright (C) 2007-2016 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	;* Header Files *
29	;*********************************************************************************************************************************
30	%include "bs3kit-template-header.mac"
31
32	%ifndef TMPL_16BIT
33	%error "16-bit only template"
34	%endif
35
36
37	;*********************************************************************************************************************************
38	;* External Symbols *
39	;*********************************************************************************************************************************
40	BS3_EXTERN_DATA16 g_bBs3CurrentMode
41	BS3_EXTERN_DATA16 g_uBs3TrapEipHint
42	BS3_EXTERN_DATA16 g_uBs3CpuDetected
43	BS3_EXTERN_DATA16 g_apfnBs3TrapHandlers_c16
44	BS3_EXTERN_SYSTEM16 Bs3Gdt
45	TMPL_BEGIN_TEXT
46	BS3_EXTERN_CMN Bs3TrapDefaultHandler
47	BS3_EXTERN_CMN Bs3RegCtxRestore
48	TMPL_BEGIN_TEXT
49
50
51	;;
52	; Generic entry points for IDT handlers, 8 byte spacing.
53	;
54	BS3_PROC_BEGIN _Bs3Trap16GenericEntries
55	BS3_PROC_BEGIN Bs3Trap16GenericEntries
56	%macro Bs3Trap16GenericEntryNoErr 1
57	push byte 0 ; 2 byte: fake error code
58	db 06ah, i ; 2 byte: push imm8 - note that this is a signextended value.
59	jmp %1 ; 3 byte
60	ALIGNCODE(8)
61	%assign i i+1
62	%endmacro
63
64	%macro Bs3Trap16GenericEntryErrCd 1
65	db 06ah, i ; 2 byte: push imm8 - note that this is a signextended value.
66	jmp %1 ; 3 byte
67	ALIGNCODE(8)
68	%assign i i+1
69	%endmacro
70
71	%assign i 0 ; start counter.
72	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 0
73	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1
74	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 2
75	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 3
76	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 4
77	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 5
78	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 6
79	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 7
80	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; 8
81	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 9
82	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; a
83	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; b
84	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; c
85	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; d
86	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; e
87	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; f (reserved)
88	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 10
89	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; 11
90	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 12
91	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 13
92	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 14
93	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 15 (reserved)
94	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 16 (reserved)
95	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 17 (reserved)
96	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 18 (reserved)
97	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 19 (reserved)
98	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1a (reserved)
99	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1b (reserved)
100	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1c (reserved)
101	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1d (reserved)
102	Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; 1e
103	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1f (reserved)
104	%rep 224
105	Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt
106	%endrep
107	BS3_PROC_END Bs3Trap16GenericEntries
108	AssertCompile(Bs3Trap16GenericEntries_EndProc - Bs3Trap16GenericEntries == 8*256)
109
110
111	;;
112	; Trap or interrupt with error code, faked if necessary.
113	;
114	; Note! This code is going to "misbehave" if the high word of ESP is not cleared.
115	;
116	BS3_PROC_BEGIN _bs3Trap16GenericTrapOrInt
117	BS3_PROC_BEGIN bs3Trap16GenericTrapOrInt
118	CPU 386
119	jmp near bs3Trap16GenericTrapErrCode80286 ; Bs3Trap16Init adjusts this on 80386+
120	push ebp
121	movzx ebp, sp
122	push ebx ; BP - 04h
123	pushfd ; BP - 08h
124	cld
125	push edx ; BP - 0ch
126	push ss ; BP - 0eh
127	push esp ; BP - 12h
128
129	;
130	; We may be comming from 32-bit code where SS is flat and ESP has a non-
131	; zero high word. We need to thunk it for C code to work correctly with
132	; [BP+xx] and [SS:BX+xx] style addressing that leaves out the high word.
133	;
134	; Note! Require ring-0 handler for non-standard stacks (SS.DPL must equal CPL).
135	;
136	mov bx, ss
137	lar ebx, bx
138	test ebx, X86LAR_F_D
139	jz .stack_fine
140	test esp, 0ffff0000h
141	jnz .stack_thunk
142	.stack_load_r0_ss16:
143	mov bx, ss
144	and bl, 3
145	AssertCompile(BS3_SEL_RING_SHIFT == 8)
146	mov bh, bl
147	add bx, BS3_SEL_R0_SS16
148	jmp .stack_load_bx_into_ss
149	.stack_thunk:
150	mov ebx, esp
151	shr ebx, 16
152	shl ebx, X86_SEL_SHIFT
153	add ebx, BS3_SEL_TILED_R0
154	cmp ebx, BS3_SEL_TILED_R0_LAST
155	ja .stack_esp_out_of_bounds
156	.stack_load_bx_into_ss:
157	mov ss, bx
158	.stack_fine:
159	movzx esp, sp
160
161	; Reserve space for the register and trap frame.
162	mov bx, (BS3TRAPFRAME_size + 7) / 8
163	.more_zeroed_space:
164	push 0
165	push 0
166	push 0
167	push 0
168	dec bx
169	jnz .more_zeroed_space
170	movzx ebx, sp
171
172	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], eax
173	mov edx, [bp - 12h] ; This isn't quite right for wrap arounds, but close enough for now
174	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], edx ; high bits
175	mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], edx ; high bits
176	mov dx, [bp - 0eh]
177	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], dx
178	mov [ss:bx + BS3TRAPFRAME.uHandlerSs], dx
179	mov edx, [bp - 0ch]
180	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], edx
181	mov edx, [bp - 8]
182	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], edx ; high bits
183	mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], edx
184	mov edx, [bp - 4]
185	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], edx
186	mov edx, [bp]
187	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], edx
188
189	mov dl, [bp + 4]
190	mov [ss:bx + BS3TRAPFRAME.bXcpt], dl
191
192	mov dx, [bp + 6]
193	;; @todo Do voodoo checks for 'int xx' or misguided hardware interrupts.
194	mov [ss:bx + BS3TRAPFRAME.uErrCd], dx
195
196	add bp, 6 ; adjust so it points to the word before the iret frame.
197	xor dx, dx
198	jmp bs3Trap16GenericCommon
199
200	.stack_esp_out_of_bounds:
201	%ifdef BS3_STRICT
202	int3
203	%endif
204	jmp .stack_esp_out_of_bounds
205	BS3_PROC_END bs3Trap16GenericTrapErrCode
206
207	;;
208	; Trap with error code - 80286 code variant.
209	;
210	BS3_PROC_BEGIN bs3Trap16GenericTrapErrCode80286
211	CPU 286
212	push bp
213	mov bp, sp
214	push bx
215	pushf
216	cld
217
218	; Reserve space for the register and trap frame.
219	mov bx, (BS3TRAPFRAME_size + 7) / 8
220	.more_zeroed_space:
221	push 0
222	push 0
223	push 0
224	push 0
225	dec bx
226	jnz .more_zeroed_space
227	mov bx, sp
228
229	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], ax
230	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], ss
231	mov [ss:bx + BS3TRAPFRAME.uHandlerSs], ss
232	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], dx
233	mov dx, [bp - 4]
234	mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], dx
235	mov dx, [bp - 2]
236	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], dx
237	mov dx, [bp]
238	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], dx
239
240	mov dl, [bp + 2]
241	mov [ss:bx + BS3TRAPFRAME.bXcpt], dl
242
243	mov dx, [bp + 4]
244	;; @todo Do voodoo checks for 'int xx' or misguided hardware interrupts.
245	mov [ss:bx + BS3TRAPFRAME.uErrCd], dx
246
247	add bp, 4 ; adjust so it points to the word before the iret frame.
248	mov dl, 1
249	jmp bs3Trap16GenericCommon
250	BS3_PROC_END bs3Trap16GenericTrapErrCode80286
251
252
253	;;
254	; Common context saving code and dispatching.
255	;
256	; @param bx Pointer to the trap frame, zero filled. The following members
257	; have been filled in by the previous code:
258	; - bXcpt
259	; - uErrCd
260	; - fHandlerRFL
261	; - Ctx.eax
262	; - Ctx.edx
263	; - Ctx.ebx
264	; - Ctx.ebp
265	; - Ctx.rflags - high bits only.
266	; - Ctx.esp - high bits only.
267	; - Ctx.ss - for same cpl frames
268	; - All other bytes are zeroed.
269	;
270	; @param bp Pointer to the word before the iret frame, i.e. where bp
271	; would be saved if this was a normal near call.
272	; @param dx One (1) if 286, zero (0) if 386+.
273	;
274	BS3_PROC_BEGIN bs3Trap16GenericCommon
275	CPU 286
276	;
277	; Fake EBP frame.
278	;
279	mov ax, [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp]
280	mov [bp], ax
281
282	;
283	; Save the remaining GPRs and segment registers.
284	;
285	test dx, dx
286	jnz .save_word_grps
287	CPU 386
288	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], ecx
289	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], edi
290	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], esi
291	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fs], fs
292	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.gs], gs
293	jmp .save_segment_registers
294	.save_word_grps:
295	CPU 286
296	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], cx
297	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], di
298	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], si
299	.save_segment_registers:
300	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ds], ds
301	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.es], es
302	mov [ss:bx + BS3TRAPFRAME.uHandlerCs], cs
303
304	;
305	; Load 16-bit data selector for the DPL we're executing at into DS and ES.
306	;
307	mov ax, ss
308	and ax, 3
309	mov cx, ax
310	shl ax, BS3_SEL_RING_SHIFT
311	or ax, cx
312	add ax, BS3_SEL_R0_DS16
313	mov ds, ax
314	mov es, ax
315
316	;
317	; Copy and update the mode now that we've got a flat DS.
318	;
319	mov al, [BS3_DATA16_WRT(g_bBs3CurrentMode)]
320	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bMode], al
321	mov cl, al
322	and cl, ~BS3_MODE_CODE_MASK
323	or cl, BS3_MODE_CODE_16
324	mov [BS3_DATA16_WRT(g_bBs3CurrentMode)], cl
325
326	;
327	; Copy iret info.
328	;
329	lea cx, [bp + 2]
330	mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], cx
331	mov cx, [bp + 2]
332	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rip], cx
333	mov cx, [bp + 6]
334	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], cx
335	mov cx, [bp + 4]
336	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cs], cx
337
338	test al, BS3_MODE_CODE_V86
339	jnz .iret_frame_v8086
340
341	mov ax, ss
342	and al, 3
343	and cl, 3
344	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bCpl], cl
345	cmp cl, al
346	je .iret_frame_same_cpl
347
348	.ret_frame_different_cpl:
349	mov cx, [bp + 10]
350	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], cx
351	mov cx, [bp + 8]
352	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx
353	mov byte [ss:bx + BS3TRAPFRAME.cbIretFrame], 5*2
354	test dx, dx
355	jnz .iret_frame_done
356	jmp .iret_frame_seed_high_eip_word
357
358	.iret_frame_same_cpl: ; (ss and high bits was saved by CPU specific part)
359	lea cx, [bp + 8]
360	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx
361	mov byte [ss:bx + BS3TRAPFRAME.cbIretFrame], 3*2
362	test dx, dx
363	jnz .iret_frame_done
364	jmp .iret_frame_seed_high_eip_word
365
366	.iret_frame_v8086:
367	CPU 386
368	or dword [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], X86_EFL_VM
369	mov byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bCpl], 3
370	or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bMode], BS3_MODE_CODE_V86 ; paranoia ^ 2
371	%if 0 ;; @todo testcase: high ESP word from V86 mode, 16-bit TSS.
372	movzx ecx, word [bp + 8]
373	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], ecx
374	%else
375	mov cx, word [bp + 8]
376	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx
377	%endif
378	mov cx, [bp + 10]
379	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], cx
380	mov cx, [bp + 12]
381	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.es], cx
382	mov cx, [bp + 14]
383	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ds], cx
384	mov cx, [bp + 16]
385	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fs], cx
386	mov cx, [bp + 18]
387	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.gs], cx
388	mov byte [ss:bx + BS3TRAPFRAME.cbIretFrame], 9*2
389	jmp .iret_frame_done
390
391	;
392	; For 386 we do special tricks to supply the high word of EIP when
393	; arriving here from 32-bit code. (ESP was seeded earlier.)
394	;
395	.iret_frame_seed_high_eip_word:
396	lar eax, [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cs]
397	jnz .iret_frame_done
398	test eax, X86LAR_F_D
399	jz .iret_frame_done
400	mov ax, [g_uBs3TrapEipHint+2]
401	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rip + 2], ax
402
403	.iret_frame_done:
404	;
405	; Control registers.
406	;
407	str [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.tr]
408	sldt [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ldtr]
409	test dx, dx
410	jnz .save_286_control_registers
411	.save_386_control_registers:
412	CPU 386
413	mov ax, ss
414	test al, 3
415	jnz .skip_crX_because_cpl_not_0
416	mov eax, cr0
417	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0], eax
418	mov eax, cr2
419	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr2], eax
420	mov eax, cr3
421	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr3], eax
422
423	test byte [1 + BS3_DATA16_WRT(g_uBs3CpuDetected)], (BS3CPU_F_CPUID >> 8) ; CR4 first appeared in later 486es.
424	jz .skip_cr4_because_not_there
425	mov eax, cr4
426	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr4], eax
427	jmp .set_flags
428
429	.skip_cr4_because_not_there:
430	mov byte [edi + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_CR4
431	jmp .set_flags
432
433	.skip_crX_because_cpl_not_0:
434	or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], \
435	BS3REG_CTX_F_NO_CR2_CR3 \| BS3REG_CTX_F_NO_CR4 \| BS3REG_CTX_F_NO_CR0_IS_MSW
436
437	CPU 286
438	.save_286_control_registers:
439	smsw [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0]
440
441	.set_flags: ; The double fault code joins us here.
442	or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_AMD64
443
444	;
445	; Dispatch it to C code.
446	;
447	.dispatch_to_handler:
448	mov di, bx
449	mov bl, byte [ss:bx + BS3TRAPFRAME.bXcpt]
450	mov bh, 0
451	shl bx, 1
452	mov bx, [bx + BS3_DATA16_WRT(_g_apfnBs3TrapHandlers_c16)]
453	or bx, bx
454	jnz .call_handler
455	mov bx, Bs3TrapDefaultHandler
456	.call_handler:
457	push ss
458	push di
459	call bx
460
461	;
462	; Resume execution using trap frame.
463	;
464	push 0
465	push ss
466	add di, BS3TRAPFRAME.Ctx
467	push di
468	call Bs3RegCtxRestore
469	.panic:
470	hlt
471	jmp .panic
472	BS3_PROC_END bs3Trap16GenericCommon
473
474
475	;;
476	; Helper.
477	;
478	; @retruns Flat address in es:di.
479	; @param di
480	; @uses eax
481	;
482	bs3Trap16TssInDiToFar1616InEsDi:
483	CPU 286
484	push ax
485
486	; ASSUME Bs3Gdt is being used.
487	push BS3_SEL_SYSTEM16
488	pop es
489	and di, 0fff8h
490	add di, Bs3Gdt wrt BS3SYSTEM16
491
492	; Load the TSS base into ax:di (di is low, ax high)
493	mov al, [es:di + (X86DESCGENERIC_BIT_OFF_BASE_HIGH1 / 8)]
494	mov ah, [es:di + (X86DESCGENERIC_BIT_OFF_BASE_HIGH2 / 8)]
495	mov di, [es:di + (X86DESCGENERIC_BIT_OFF_BASE_LOW / 8)]
496
497	; Convert ax to tiled selector, if not within the tiling area we read
498	; random BS3SYSTEM16 bits as that's preferable to #GP'ing.
499	shl ax, X86_SEL_SHIFT
500	cmp ax, BS3_SEL_TILED_LAST - BS3_SEL_TILED
501	%ifdef BS3_STRICT
502	jbe .tiled
503	int3
504	%endif
505	ja .return ; don't crash again.
506	.tiled:
507	add ax, BS3_SEL_TILED
508	mov es, ax
509	.return:
510	pop ax
511	ret
512
513
514	;;
515	; Double fault handler.
516	;
517	; We don't have to load any selectors or clear anything in EFLAGS because the
518	; TSS specified sane values which got loaded during the task switch.
519	;
520	; @param dx Zero (0) for indicating 386+ to the common code.
521	;
522	BS3_PROC_BEGIN _Bs3Trap16DoubleFaultHandler80386
523	BS3_PROC_BEGIN Bs3Trap16DoubleFaultHandler80386
524	CPU 386
525	push 0 ; We'll copy the rip from the other TSS here later to create a more sensible call chain.
526	push ebp
527	mov bp, sp
528	pushfd ; Handler flags.
529
530	; Reserve space for the register and trap frame.
531	mov bx, (BS3TRAPFRAME_size + 15) / 16
532	.more_zeroed_space:
533	push dword 0
534	push dword 0
535	push dword 0
536	push dword 0
537	dec bx
538	jz .more_zeroed_space
539	mov bx, sp
540
541	;
542	; Fill in the high GRP register words before we mess them up.
543	;
544	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], eax
545	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], ebx
546	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], ecx
547	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], edx
548	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], esi
549	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], edi
550	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], ebp
551	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], esp
552
553	;
554	; FS and GS are not part of the 16-bit TSS because they are 386+ specfic.
555	;
556	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fs], fs
557	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.gs], gs
558
559	;
560	; Fill in the non-context trap frame bits.
561	;
562	mov ecx, [bp - 4]
563	mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], ecx
564	mov byte [ss:bx + BS3TRAPFRAME.bXcpt], X86_XCPT_DF
565	mov [ss:bx + BS3TRAPFRAME.uHandlerCs], cs
566	mov [ss:bx + BS3TRAPFRAME.uHandlerSs], ss
567	mov ecx, esp
568	lea cx, [bp + 8]
569	mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], ecx
570	mov cx, [bp + 6]
571	mov [ss:bx + BS3TRAPFRAME.uErrCd], cx
572
573	;
574	; Copy 80386+ control registers.
575	;
576	mov ecx, cr0
577	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0], ecx
578	mov ecx, cr2
579	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr2], ecx
580	mov ecx, cr3
581	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr3], ecx
582
583	test byte [1 + BS3_DATA16_WRT(g_uBs3CpuDetected)], (BS3CPU_F_CPUID >> 8) ; CR4 first appeared in later 486es.
584	jz .skip_cr4_because_not_there
585	mov ecx, cr4
586	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr4], ecx
587	jmp .common
588
589	.skip_cr4_because_not_there:
590	mov byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_CR4
591
592	;
593	; Copy the register state from the previous task segment.
594	; The 80286 code with join us here.
595	;
596	.common:
597	CPU 286
598	; Find our TSS.
599	str di
600	call bs3Trap16TssInDiToFar1616InEsDi
601
602	; Find the previous TSS.
603	mov di, [es:di + X86TSS32.selPrev]
604	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.tr], ax
605	call bs3Trap16TssInDiToFar1616InEsDi
606
607	; Do the copying.
608	mov cx, [es:di + X86TSS16.ax]
609	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], cx
610	mov cx, [es:di + X86TSS16.cx]
611	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], cx
612	mov cx, [es:di + X86TSS16.dx]
613	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], cx
614	mov cx, [es:di + X86TSS16.bx]
615	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], cx
616	mov cx, [es:di + X86TSS16.sp]
617	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx
618	mov cx, [es:di + X86TSS16.bp]
619	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], cx
620	mov [bp], cx ; For better call stacks.
621	mov cx, [es:di + X86TSS16.si]
622	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], cx
623	mov cx, [es:di + X86TSS16.di]
624	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], cx
625	mov cx, [es:di + X86TSS16.si]
626	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], cx
627	mov cx, [es:di + X86TSS16.flags]
628	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], cx
629	mov cx, [es:di + X86TSS16.ip]
630	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rip], cx
631	mov [bp + 2], cx ; For better call stacks.
632	mov cx, [es:di + X86TSS16.cs]
633	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cs], cx
634	mov cx, [es:di + X86TSS16.ds]
635	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ds], cx
636	mov cx, [es:di + X86TSS16.es]
637	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.es], cx
638	mov cx, [es:di + X86TSS16.ss]
639	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], cx
640	mov cx, [es:di + X86TSS16.selLdt] ; Note! This isn't necessarily the ldtr at the time of the fault.
641	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ldtr], cx
642
643	;
644	; Set CPL; copy and update mode.
645	;
646	mov cl, [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss]
647	and cl, 3
648	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bCpl], cl
649
650	mov cl, [BS3_DATA16_WRT(g_bBs3CurrentMode)]
651	mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bMode], cl
652	and cl, ~BS3_MODE_CODE_MASK
653	or cl, BS3_MODE_CODE_16
654	mov [BS3_DATA16_WRT(g_bBs3CurrentMode)], cl
655
656	;
657	; Join code paths with the generic handler code.
658	;
659	jmp bs3Trap16GenericCommon.set_flags
660	BS3_PROC_END Bs3Trap16DoubleFaultHandler
661
662
663	;;
664	; Double fault handler.
665	;
666	; We don't have to load any selectors or clear anything in EFLAGS because the
667	; TSS specified sane values which got loaded during the task switch.
668	;
669	; @param dx One (1) for indicating 386+ to the common code.
670	;
671	BS3_PROC_BEGIN _Bs3Trap16DoubleFaultHandler80286
672	BS3_PROC_BEGIN Bs3Trap16DoubleFaultHandler80286
673	CPU 286
674	push 0 ; We'll copy the rip from the other TSS here later to create a more sensible call chain.
675	push bp
676	mov bp, sp
677	pushf ; Handler flags.
678
679	; Reserve space for the register and trap frame.
680	mov bx, (BS3TRAPFRAME_size + 7) / 8
681	.more_zeroed_space:
682	push 0
683	push 0
684	push 0
685	push 0
686	dec bx
687	jz .more_zeroed_space
688	mov bx, sp
689
690	;
691	; Fill in the non-context trap frame bits.
692	;
693	mov cx, [bp - 2]
694	mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], cx
695	mov byte [ss:bx + BS3TRAPFRAME.bXcpt], X86_XCPT_DF
696	mov [ss:bx + BS3TRAPFRAME.uHandlerCs], cs
697	mov [ss:bx + BS3TRAPFRAME.uHandlerSs], ss
698	lea cx, [bp + 8]
699	mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], cx
700	mov cx, [bp + 6]
701	mov [ss:bx + BS3TRAPFRAME.uErrCd], cx
702
703	;
704	; Copy 80286 specific control register.
705	;
706	smsw [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0]
707
708	jmp Bs3Trap16DoubleFaultHandler80386.common
709	BS3_PROC_END Bs3Trap16DoubleFaultHandler80286
710
711

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source: vbox/trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-c16-Trap16Generic.asm@ 66316

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