; $Id: bs3-c16-TrapRmV86Generic.asm $ ;; @file ; BS3Kit - Trap, 16-bit assembly handlers for real mode and v8086. ; ; ; Copyright (C) 2007-2023 Oracle and/or its affiliates. ; ; This file is part of VirtualBox base platform packages, as ; available from https://www.virtualbox.org. ; ; This program is free software; you can redistribute it and/or ; modify it under the terms of the GNU General Public License ; as published by the Free Software Foundation, in version 3 of the ; License. ; ; This program is distributed in the hope that it will be useful, but ; WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ; General Public License for more details. ; ; You should have received a copy of the GNU General Public License ; along with this program; if not, see . ; ; The contents of this file may alternatively be used under the terms ; of the Common Development and Distribution License Version 1.0 ; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included ; in the VirtualBox distribution, in which case the provisions of the ; CDDL are applicable instead of those of the GPL. ; ; You may elect to license modified versions of this file under the ; terms and conditions of either the GPL or the CDDL or both. ; ; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 ; ;********************************************************************************************************************************* ;* Header Files * ;********************************************************************************************************************************* %include "bs3kit-template-header.mac" %ifndef TMPL_16BIT %error "16-bit only template" %endif ;********************************************************************************************************************************* ;* External Symbols * ;********************************************************************************************************************************* BS3_EXTERN_DATA16 g_bBs3CurrentMode BS3_EXTERN_DATA16 g_uBs3TrapEipHint BS3_EXTERN_DATA16 g_uBs3CpuDetected BS3_EXTERN_DATA16 g_apfnBs3TrapHandlers_c16 TMPL_BEGIN_TEXT BS3_EXTERN_CMN Bs3TrapDefaultHandler BS3_EXTERN_CMN Bs3RegCtxRestore TMPL_BEGIN_TEXT ;; ; Generic entry points for IDT handlers, 8 byte spacing. ; BS3_PROC_BEGIN _Bs3TrapRmV86GenericEntries BS3_PROC_BEGIN Bs3TrapRmV86GenericEntries %macro Bs3TrapRmV86GenericEntryNoErr 1 push ax ; 1 byte: Reserve space for fake error cd. (BP(+2) + 4) push ax ; 1 byte: Save AX (BP(+2) + 2) mov ax, i | 00000h ; 2 bytes: AL = trap/interrupt number; AH=indicate no error code jmp %1 ; 3 bytes: Jump to handler code ALIGNCODE(8) %assign i i+1 %endmacro %macro Bs3TrapRmV86GenericEntryErrCd 1 Bs3TrapRmV86GenericEntryNoErr %1 ; No error code pushed in real mode or V86 mode. %endmacro %assign i 0 ; start counter. Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 0 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 1 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 2 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 3 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 4 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 5 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 6 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 7 Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; 8 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 9 Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; a Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; b Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; c Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; d Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; e Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; f (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 10 Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; 11 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 12 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 13 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 14 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 15 (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 16 (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 17 (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 18 (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 19 (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 1a (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 1b (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 1c (reserved) Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 1d (reserved) Bs3TrapRmV86GenericEntryErrCd bs3TrapRmV86GenericTrapOrInt ; 1e Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt ; 1f (reserved) %rep 224 Bs3TrapRmV86GenericEntryNoErr bs3TrapRmV86GenericTrapOrInt %endrep BS3_PROC_END Bs3TrapRmV86GenericEntries AssertCompile(Bs3TrapRmV86GenericEntries_EndProc - Bs3TrapRmV86GenericEntries == 8*256) ;; ; Trap or interrupt with error code, faked if necessary. ; ; early 386+ stack (movzx ebp, sp): ; [bp + 000h] ebp ; [bp + 004h] ax ; [bp + 006h] errcd [bp'+0] <--- bp at jmp to common code. ; [bp + 008h] cs [bp'+2] ; [bp + 00ah] ip [bp'+4] ; [bp + 00ch] flags [bp'+6] ; ([bp + 00eh] post-iret sp value) [bp'+8] ; BS3_PROC_BEGIN _bs3TrapRmV86GenericTrapOrInt BS3_PROC_BEGIN bs3TrapRmV86GenericTrapOrInt CPU 386 jmp near bs3TrapRmV86GenericTrapErrCode8086 ; Bs3TrapRmV86Init adjusts this on 80386+ push ebp movzx ebp, sp push ebx ; BP - 04h pushfd ; BP - 08h cld push edx ; BP - 0ch push ss ; BP - 0eh push esp ; BP - 12h ; Reserve space for the register and trap frame. mov bx, (BS3TRAPFRAME_size + 7) / 8 .more_zeroed_space: push 0 push 0 push 0 push 0 dec bx jnz .more_zeroed_space movzx ebx, sp mov edx, [bp - 12h] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], edx ; high bits mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], edx ; high bits mov dx, [bp - 0eh] mov [ss:bx + BS3TRAPFRAME.uHandlerSs], dx mov edx, [bp - 0ch] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], edx mov edx, [bp - 8] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], edx ; high bits mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], edx mov edx, [bp - 4] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], edx mov edx, [bp] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], edx mov edx, eax ; high bits mov dx, [bp + 4] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], edx mov [ss:bx + BS3TRAPFRAME.bXcpt], al test ah, 0ffh jz .no_error_code mov dx, [bp + 6] mov [ss:bx + BS3TRAPFRAME.uErrCd], dx .no_error_code: add bp, 6 ; adjust so it points to the word before the iret frame. xor dx, dx jmp bs3TrapRmV86GenericCommon BS3_PROC_END bs3TrapRmV86GenericTrapErrCode ;; ; Trap with error code - 8086/V20/80186/80286 code variant. ; BS3_PROC_BEGIN bs3TrapRmV86GenericTrapErrCode8086 CPU 8086 push bp mov bp, sp push bx ; BP - 2 pushf ; BP - 4 push ax ; BP - 6 cld ; Reserve space for the register and trap frame. mov bx, (BS3TRAPFRAME_size + 7) / 8 xor ax, ax .more_zeroed_space: push ax push ax push ax push ax dec bx jnz .more_zeroed_space mov bx, sp mov [ss:bx + BS3TRAPFRAME.uHandlerSs], ss mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], dx mov dx, [bp - 4] mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], dx mov dx, [bp - 2] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], dx mov dx, [bp] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], dx mov dx, [bp + 2] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], dx mov ax, [bp - 6] mov [ss:bx + BS3TRAPFRAME.bXcpt], al test ah, 0ffh jz .no_error_code mov dx, [bp + 4] mov [ss:bx + BS3TRAPFRAME.uErrCd], dx .no_error_code: add bp, 4 ; adjust so it points to the word before the iret frame. mov dl, 1 jmp bs3TrapRmV86GenericCommon BS3_PROC_END bs3TrapRmV86GenericTrapErrCode8086 ;; ; Common context saving code and dispatching. ; ; @param ss:bx Pointer to the trap frame, zero filled. The following members ; have been filled in by the previous code: ; - bXcpt ; - uErrCd ; - fHandlerRFL ; - Ctx.eax ; - Ctx.edx ; - Ctx.ebx ; - Ctx.ebp ; - Ctx.rflags - high bits only. ; - Ctx.esp - high bits only. ; - All other bytes are zeroed. ; ; @param bp Pointer to the word before the iret frame, i.e. where bp ; would be saved if this was a normal near call. ; @param dx One (1) if 286, zero (0) if 386+. ; BS3_PROC_BEGIN bs3TrapRmV86GenericCommon CPU 8086 ; ; Fake EBP frame. ; mov ax, [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp] mov [bp], ax ; ; Save the remaining GPRs and segment registers. ; test dx, dx jnz .save_word_grps CPU 386 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], ecx mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], edi mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], esi mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fs], fs mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.gs], gs jmp .save_segment_registers .save_word_grps: CPU 8086 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], cx mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], di mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], si .save_segment_registers: mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ds], ds mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.es], es mov [ss:bx + BS3TRAPFRAME.uHandlerCs], cs ; ; Load 16-bit BS3KIT_GRPNM_DATA16 into DS and ES so we can access globals. ; mov ax, BS3KIT_GRPNM_DATA16 mov ds, ax mov es, ax ; ; Copy the mode now that we've got a flat DS. We don't need to update ; it as it didn't change. ; mov al, [BS3_DATA16_WRT(g_bBs3CurrentMode)] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bMode], al ; ; Copy iret info. ; lea cx, [bp + 2] mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], cx mov cx, [bp + 2] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rip], cx mov cx, [bp + 6] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], cx mov cx, [bp + 4] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cs], cx mov cx, ss mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], cx lea cx, [bp + 8] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx mov byte [ss:bx + BS3TRAPFRAME.cbIretFrame], 3*2 ; The VM flag and CPL. test al, BS3_MODE_CODE_V86 jz .dont_set_vm or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags + 2], X86_EFL_VM >> 16 mov byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bCpl], 3 .dont_set_vm: ; ; Control registers. ; ; Since we're in real or v8086 here, we cannot save TR and LDTR. ; But get MSW (CR0) first since that's always accessible and we ; need it even on a 386 to check whether we're in v8086 mode or not. ; cmp byte [BS3_DATA16_WRT(g_uBs3CpuDetected)], BS3CPU_80286 jb .skip_control_registers_because_80186_or_older CPU 286 smsw ax mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0], ax test dx, dx jnz .set_flags .save_386_control_registers: CPU 386 ; 386 control registers are not accessible from virtual 8086 mode. test al, X86_CR0_PE jnz .skip_crX_because_v8086 mov eax, cr0 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0], eax mov eax, cr2 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr2], eax mov eax, cr3 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr3], eax test byte [1 + BS3_DATA16_WRT(g_uBs3CpuDetected)], (BS3CPU_F_CPUID >> 8) ; CR4 first appeared in later 486es. jz .skip_cr4_because_not_there mov eax, cr4 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr4], eax jmp .set_flags .skip_cr4_because_not_there: mov byte [edi + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_CR4 jmp .set_flags CPU 8086 .skip_control_registers_because_80186_or_older: .skip_crX_because_v8086: or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], \ BS3REG_CTX_F_NO_CR0_IS_MSW | BS3REG_CTX_F_NO_CR2_CR3 | BS3REG_CTX_F_NO_CR4 .set_flags: ; The double fault code joins us here. or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_AMD64 | BS3REG_CTX_F_NO_TR_LDTR ; ; Dispatch it to C code. ; .dispatch_to_handler: mov di, bx mov bl, byte [ss:bx + BS3TRAPFRAME.bXcpt] mov bh, 0 shl bx, 1 mov bx, [bx + BS3_DATA16_WRT(_g_apfnBs3TrapHandlers_c16)] or bx, bx jnz .call_handler mov bx, Bs3TrapDefaultHandler .call_handler: push ss push di call bx ; ; Resume execution using trap frame. ; xor ax, ax push ax push ss add di, BS3TRAPFRAME.Ctx push di call Bs3RegCtxRestore .panic: hlt jmp .panic BS3_PROC_END bs3TrapRmV86GenericCommon