; $Id: bs3-c16-Trap16Generic.asm 69222 2017-10-24 15:10:29Z vboxsync $ ;; @file ; BS3Kit - Trap, 16-bit assembly handlers. ; ; ; Copyright (C) 2007-2017 Oracle Corporation ; ; This file is part of VirtualBox Open Source Edition (OSE), as ; available from http://www.virtualbox.org. This file is free software; ; you can redistribute it and/or modify it under the terms of the GNU ; General Public License (GPL) as published by the Free Software ; Foundation, in version 2 as it comes in the "COPYING" file of the ; VirtualBox OSE distribution. VirtualBox OSE is distributed in the ; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. ; ; The contents of this file may alternatively be used under the terms ; of the Common Development and Distribution License Version 1.0 ; (CDDL) only, as it comes in the "COPYING.CDDL" file of the ; VirtualBox OSE 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. ; ;********************************************************************************************************************************* ;* 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 BS3_EXTERN_SYSTEM16 Bs3Gdt 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 _Bs3Trap16GenericEntries BS3_PROC_BEGIN Bs3Trap16GenericEntries %macro Bs3Trap16GenericEntryNoErr 1 push byte 0 ; 2 byte: fake error code db 06ah, i ; 2 byte: push imm8 - note that this is a signextended value. jmp %1 ; 3 byte ALIGNCODE(8) %assign i i+1 %endmacro %macro Bs3Trap16GenericEntryErrCd 1 db 06ah, i ; 2 byte: push imm8 - note that this is a signextended value. jmp %1 ; 3 byte ALIGNCODE(8) %assign i i+1 %endmacro %assign i 0 ; start counter. Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 0 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 2 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 3 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 4 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 5 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 6 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 7 Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; 8 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 9 Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; a Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; b Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; c Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; d Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; e Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; f (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 10 Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; 11 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 12 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 13 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 14 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 15 (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 16 (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 17 (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 18 (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 19 (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1a (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1b (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1c (reserved) Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1d (reserved) Bs3Trap16GenericEntryErrCd bs3Trap16GenericTrapOrInt ; 1e Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt ; 1f (reserved) %rep 224 Bs3Trap16GenericEntryNoErr bs3Trap16GenericTrapOrInt %endrep BS3_PROC_END Bs3Trap16GenericEntries AssertCompile(Bs3Trap16GenericEntries_EndProc - Bs3Trap16GenericEntries == 8*256) ;; ; Trap or interrupt with error code, faked if necessary. ; ; Note! This code is going to "misbehave" if the high word of ESP is not cleared. ; BS3_PROC_BEGIN _bs3Trap16GenericTrapOrInt BS3_PROC_BEGIN bs3Trap16GenericTrapOrInt CPU 386 jmp near bs3Trap16GenericTrapErrCode80286 ; Bs3Trap16Init 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 ; ; We may be comming from 32-bit code where SS is flat and ESP has a non- ; zero high word. We need to thunk it for C code to work correctly with ; [BP+xx] and [SS:BX+xx] style addressing that leaves out the high word. ; ; Note! Require ring-0 handler for non-standard stacks (SS.DPL must equal CPL). ; mov bx, ss lar ebx, bx test ebx, X86LAR_F_D jz .stack_fine test esp, 0ffff0000h jnz .stack_thunk .stack_load_r0_ss16: mov bx, ss and bl, 3 AssertCompile(BS3_SEL_RING_SHIFT == 8) mov bh, bl add bx, BS3_SEL_R0_SS16 jmp .stack_load_bx_into_ss .stack_thunk: mov ebx, esp shr ebx, 16 shl ebx, X86_SEL_SHIFT add ebx, BS3_SEL_TILED_R0 cmp ebx, BS3_SEL_TILED_R0_LAST ja .stack_esp_out_of_bounds .stack_load_bx_into_ss: mov ss, bx .stack_fine: movzx esp, sp ; 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 [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], eax mov edx, [bp - 12h] ; This isn't quite right for wrap arounds, but close enough for now 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.Ctx + BS3REGCTX.ss], dx 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 dl, [bp + 4] mov [ss:bx + BS3TRAPFRAME.bXcpt], dl mov dx, [bp + 6] ;; @todo Do voodoo checks for 'int xx' or misguided hardware interrupts. mov [ss:bx + BS3TRAPFRAME.uErrCd], dx add bp, 6 ; adjust so it points to the word before the iret frame. xor dx, dx jmp bs3Trap16GenericCommon .stack_esp_out_of_bounds: %ifdef BS3_STRICT int3 %endif jmp .stack_esp_out_of_bounds BS3_PROC_END bs3Trap16GenericTrapErrCode ;; ; Trap with error code - 80286 code variant. ; BS3_PROC_BEGIN bs3Trap16GenericTrapErrCode80286 CPU 286 push bp mov bp, sp push bx pushf cld ; 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 mov bx, sp mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], ax mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], ss 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 dl, [bp + 2] mov [ss:bx + BS3TRAPFRAME.bXcpt], dl mov dx, [bp + 4] ;; @todo Do voodoo checks for 'int xx' or misguided hardware interrupts. mov [ss:bx + BS3TRAPFRAME.uErrCd], dx add bp, 4 ; adjust so it points to the word before the iret frame. mov dl, 1 jmp bs3Trap16GenericCommon BS3_PROC_END bs3Trap16GenericTrapErrCode80286 ;; ; Common context saving code and dispatching. ; ; @param 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. ; - Ctx.ss - for same cpl frames ; - 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 bs3Trap16GenericCommon CPU 286 ; ; 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 286 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 data selector for the DPL we're executing at into DS and ES. ; mov ax, ss and ax, 3 mov cx, ax shl ax, BS3_SEL_RING_SHIFT or ax, cx add ax, BS3_SEL_R0_DS16 mov ds, ax mov es, ax ; ; Copy and update the mode now that we've got a flat DS. ; mov al, [BS3_DATA16_WRT(g_bBs3CurrentMode)] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bMode], al mov cl, al and cl, ~BS3_MODE_CODE_MASK or cl, BS3_MODE_CODE_16 mov [BS3_DATA16_WRT(g_bBs3CurrentMode)], cl ; ; 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 test al, BS3_MODE_CODE_V86 jnz .iret_frame_v8086 mov ax, ss and al, 3 and cl, 3 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bCpl], cl cmp cl, al je .iret_frame_same_cpl .ret_frame_different_cpl: mov cx, [bp + 10] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], cx mov cx, [bp + 8] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx mov byte [ss:bx + BS3TRAPFRAME.cbIretFrame], 5*2 test dx, dx jnz .iret_frame_done jmp .iret_frame_seed_high_eip_word .iret_frame_same_cpl: ; (ss and high bits was saved by CPU specific part) lea cx, [bp + 8] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx mov byte [ss:bx + BS3TRAPFRAME.cbIretFrame], 3*2 test dx, dx jnz .iret_frame_done jmp .iret_frame_seed_high_eip_word .iret_frame_v8086: CPU 386 or dword [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], X86_EFL_VM mov byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bCpl], 3 or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bMode], BS3_MODE_CODE_V86 ; paranoia ^ 2 %if 0 ;; @todo testcase: high ESP word from V86 mode, 16-bit TSS. movzx ecx, word [bp + 8] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], ecx %else mov cx, word [bp + 8] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx %endif mov cx, [bp + 10] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], cx mov cx, [bp + 12] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.es], cx mov cx, [bp + 14] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ds], cx mov cx, [bp + 16] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fs], cx mov cx, [bp + 18] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.gs], cx mov byte [ss:bx + BS3TRAPFRAME.cbIretFrame], 9*2 jmp .iret_frame_done ; ; For 386 we do special tricks to supply the high word of EIP when ; arriving here from 32-bit code. (ESP was seeded earlier.) ; .iret_frame_seed_high_eip_word: lar eax, [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cs] jnz .iret_frame_done test eax, X86LAR_F_D jz .iret_frame_done mov ax, [g_uBs3TrapEipHint+2] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rip + 2], ax .iret_frame_done: ; ; Control registers. ; str [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.tr] sldt [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ldtr] test dx, dx jnz .save_286_control_registers .save_386_control_registers: CPU 386 mov ax, ss test al, 3 jnz .skip_crX_because_cpl_not_0 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 .skip_crX_because_cpl_not_0: or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], \ BS3REG_CTX_F_NO_CR2_CR3 | BS3REG_CTX_F_NO_CR4 | BS3REG_CTX_F_NO_CR0_IS_MSW CPU 286 .save_286_control_registers: smsw [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0] .set_flags: ; The double fault code joins us here. or byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_AMD64 ; ; 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. ; push 0 push ss add di, BS3TRAPFRAME.Ctx push di call Bs3RegCtxRestore .panic: hlt jmp .panic BS3_PROC_END bs3Trap16GenericCommon ;; ; Helper. ; ; @retruns Flat address in es:di. ; @param di ; @uses eax ; bs3Trap16TssInDiToFar1616InEsDi: CPU 286 push ax ; ASSUME Bs3Gdt is being used. push BS3_SEL_SYSTEM16 pop es and di, 0fff8h add di, Bs3Gdt wrt BS3SYSTEM16 ; Load the TSS base into ax:di (di is low, ax high) mov al, [es:di + (X86DESCGENERIC_BIT_OFF_BASE_HIGH1 / 8)] mov ah, [es:di + (X86DESCGENERIC_BIT_OFF_BASE_HIGH2 / 8)] mov di, [es:di + (X86DESCGENERIC_BIT_OFF_BASE_LOW / 8)] ; Convert ax to tiled selector, if not within the tiling area we read ; random BS3SYSTEM16 bits as that's preferable to #GP'ing. shl ax, X86_SEL_SHIFT cmp ax, BS3_SEL_TILED_LAST - BS3_SEL_TILED %ifdef BS3_STRICT jbe .tiled int3 %endif ja .return ; don't crash again. .tiled: add ax, BS3_SEL_TILED mov es, ax .return: pop ax ret ;; ; Double fault handler. ; ; We don't have to load any selectors or clear anything in EFLAGS because the ; TSS specified sane values which got loaded during the task switch. ; ; @param dx Zero (0) for indicating 386+ to the common code. ; BS3_PROC_BEGIN _Bs3Trap16DoubleFaultHandler80386 BS3_PROC_BEGIN Bs3Trap16DoubleFaultHandler80386 CPU 386 push 0 ; We'll copy the rip from the other TSS here later to create a more sensible call chain. push ebp mov bp, sp pushfd ; Handler flags. ; Reserve space for the register and trap frame. mov bx, (BS3TRAPFRAME_size + 15) / 16 .more_zeroed_space: push dword 0 push dword 0 push dword 0 push dword 0 dec bx jz .more_zeroed_space mov bx, sp ; ; Fill in the high GRP register words before we mess them up. ; mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], eax mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], ebx mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], ecx mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], edx mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], esi mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], edi mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], ebp mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], esp ; ; FS and GS are not part of the 16-bit TSS because they are 386+ specfic. ; mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fs], fs mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.gs], gs ; ; Fill in the non-context trap frame bits. ; mov ecx, [bp - 4] mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], ecx mov byte [ss:bx + BS3TRAPFRAME.bXcpt], X86_XCPT_DF mov [ss:bx + BS3TRAPFRAME.uHandlerCs], cs mov [ss:bx + BS3TRAPFRAME.uHandlerSs], ss mov ecx, esp lea cx, [bp + 8] mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], ecx mov cx, [bp + 6] mov [ss:bx + BS3TRAPFRAME.uErrCd], cx ; ; Copy 80386+ control registers. ; mov ecx, cr0 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0], ecx mov ecx, cr2 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr2], ecx mov ecx, cr3 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr3], ecx 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 ecx, cr4 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr4], ecx jmp .common .skip_cr4_because_not_there: mov byte [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_CR4 ; ; Copy the register state from the previous task segment. ; The 80286 code with join us here. ; .common: CPU 286 ; Find our TSS. str di call bs3Trap16TssInDiToFar1616InEsDi ; Find the previous TSS. mov di, [es:di + X86TSS32.selPrev] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.tr], ax call bs3Trap16TssInDiToFar1616InEsDi ; Do the copying. mov cx, [es:di + X86TSS16.ax] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rax], cx mov cx, [es:di + X86TSS16.cx] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rcx], cx mov cx, [es:di + X86TSS16.dx] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdx], cx mov cx, [es:di + X86TSS16.bx] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbx], cx mov cx, [es:di + X86TSS16.sp] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsp], cx mov cx, [es:di + X86TSS16.bp] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rbp], cx mov [bp], cx ; For better call stacks. mov cx, [es:di + X86TSS16.si] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], cx mov cx, [es:di + X86TSS16.di] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rdi], cx mov cx, [es:di + X86TSS16.si] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rsi], cx mov cx, [es:di + X86TSS16.flags] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rflags], cx mov cx, [es:di + X86TSS16.ip] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.rip], cx mov [bp + 2], cx ; For better call stacks. mov cx, [es:di + X86TSS16.cs] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cs], cx mov cx, [es:di + X86TSS16.ds] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ds], cx mov cx, [es:di + X86TSS16.es] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.es], cx mov cx, [es:di + X86TSS16.ss] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss], cx mov cx, [es:di + X86TSS16.selLdt] ; Note! This isn't necessarily the ldtr at the time of the fault. mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ldtr], cx ; ; Set CPL; copy and update mode. ; mov cl, [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.ss] and cl, 3 mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bCpl], cl mov cl, [BS3_DATA16_WRT(g_bBs3CurrentMode)] mov [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.bMode], cl and cl, ~BS3_MODE_CODE_MASK or cl, BS3_MODE_CODE_16 mov [BS3_DATA16_WRT(g_bBs3CurrentMode)], cl ; ; Join code paths with the generic handler code. ; jmp bs3Trap16GenericCommon.set_flags BS3_PROC_END Bs3Trap16DoubleFaultHandler ;; ; Double fault handler. ; ; We don't have to load any selectors or clear anything in EFLAGS because the ; TSS specified sane values which got loaded during the task switch. ; ; @param dx One (1) for indicating 386+ to the common code. ; BS3_PROC_BEGIN _Bs3Trap16DoubleFaultHandler80286 BS3_PROC_BEGIN Bs3Trap16DoubleFaultHandler80286 CPU 286 push 0 ; We'll copy the rip from the other TSS here later to create a more sensible call chain. push bp mov bp, sp pushf ; Handler flags. ; 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 jz .more_zeroed_space mov bx, sp ; ; Fill in the non-context trap frame bits. ; mov cx, [bp - 2] mov [ss:bx + BS3TRAPFRAME.fHandlerRfl], cx mov byte [ss:bx + BS3TRAPFRAME.bXcpt], X86_XCPT_DF mov [ss:bx + BS3TRAPFRAME.uHandlerCs], cs mov [ss:bx + BS3TRAPFRAME.uHandlerSs], ss lea cx, [bp + 8] mov [ss:bx + BS3TRAPFRAME.uHandlerRsp], cx mov cx, [bp + 6] mov [ss:bx + BS3TRAPFRAME.uErrCd], cx ; ; Copy 80286 specific control register. ; smsw [ss:bx + BS3TRAPFRAME.Ctx + BS3REGCTX.cr0] jmp Bs3Trap16DoubleFaultHandler80386.common BS3_PROC_END Bs3Trap16DoubleFaultHandler80286