; $Id: bs3-mode-TrapSystemCallHandler.asm $ ;; @file ; BS3Kit - System call trap handler. ; ; ; Copyright (C) 2007-2019 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" ;********************************************************************************************************************************* ;* External Symbols * ;********************************************************************************************************************************* BS3_EXTERN_DATA16 g_bBs3CurrentMode %if TMPL_BITS != 64 BS3_EXTERN_DATA16 g_uBs3CpuDetected %endif %if TMPL_BITS == 16 BS3_EXTERN_DATA16 g_uBs3TrapEipHint %endif TMPL_BEGIN_TEXT BS3_EXTERN_CMN Bs3SelProtFar32ToFlat32 BS3_EXTERN_CMN Bs3RegCtxConvertToRingX BS3_EXTERN_CMN Bs3RegCtxRestore BS3_EXTERN_CMN Bs3Panic BS3_BEGIN_TEXT16 extern Bs3PrintStrN_c16_CX_Bytes_At_DS_SI TMPL_BEGIN_TEXT ;; ; System call handler. ; ; This is an assembly trap handler that is called in response to a system call ; request from 'user' code. The only fixed parameter is [ER]AX which contains ; the system call number. Other registers are assigned on a per system call ; basis, ditto for which registers are preserved and which are used to return ; stuff. Generally, though, we preserve all registers not used as return ; values or otherwise implicitly transformed by the call. ; ; Note! The 16-bit versions of this code must be careful with using extended ; registers as we wish this code to work on real 80286 (maybe even 8086) ; CPUs too! ; BS3_PROC_BEGIN_MODE Bs3TrapSystemCallHandler, BS3_PBC_NEAR ; Near because we'll probably only ever need this from CGROUP16. ; ; This prologue is kind of complicated because of 80286 and older CPUs ; as well as different requirements for 64-bit and the other modes. ; %define VAR_CALLER_BP [xBP] %if TMPL_BITS != 64 %define VAR_CALLER_DS [xBP - xCB] %endif %define VAR_CALLER_BX [xBP - sCB*1 - xCB] ; Note! the upper word is not clean on pre-386 (16-bit mode). %define VAR_CALLER_AX [xBP - sCB*2 - xCB] %define VAR_CALLER_CX [xBP - sCB*3 - xCB] %define VAR_CALLER_DX [xBP - sCB*4 - xCB] %define VAR_CALLER_SI [xBP - sCB*5 - xCB] %define VAR_CALLER_SI_HI [xBP - sCB*5 - xCB + 2] %define VAR_CALLER_DI [xBP - sCB*6 - xCB] %define VAR_CALLER_DI_HI [xBP - sCB*6 - xCB + 2] %if TMPL_BITS == 16 %define VAR_CALLER_EBP [xBP - sCB*7 - xCB] %define VAR_CALLER_ESP [xBP - sCB*8 - xCB] %define VAR_CALLER_EFLAGS [xBP - sCB*9 - xCB] %define VAR_CALLER_MODE [xBP - sCB*9 - xCB*2] %define BP_TOP_STACK_EXPR xBP - sCB*9 - xCB*2 %else %define VAR_CALLER_MODE [xBP - sCB*6 - xCB*2] %define BP_TOP_STACK_EXPR xBP - sCB*6 - xCB*2 %endif push xBP mov xBP, xSP %if TMPL_BITS == 64 push 0 mov [rsp+2], es mov [rsp], ds %else push ds %ifdef TMPL_CMN_R86 push BS3_SEL_DATA16 %else push RT_CONCAT(BS3_SEL_R0_DS,TMPL_BITS) %endif pop ds ; DS = BS3KIT_GRPNM_DATA16 or FLAT and we can safely access data %if TMPL_BITS == 16 && (TMPL_MODE == BS3_MODE_RM || TMPL_MODE == BS3_MODE_PE16) cmp byte [BS3_DATA16_WRT(g_uBs3CpuDetected)], BS3CPU_80286 jbe .prologue_pre_80386 %endif %endif push sBX push sAX push sCX push sDX push sSI push sDI %if TMPL_BITS == 16 push ebp push esp pushfd %if TMPL_MODE == BS3_MODE_RM || TMPL_MODE == BS3_MODE_PE16 jmp .prologue_end .prologue_pre_80386: push bx ; dummy push bx xor bx, bx push bx ; dummy push ax push bx ; dummy push cx push bx ; dummy push dx push bx ; dummy push si push bx ; dummy push di sub sp, 0ch ; dummy %endif %endif .prologue_end: ; ; VAR_CALLER_MODE: Save the current mode (important for v8086 with 16-bit kernel). ; xor xBX, xBX mov bl, [BS3_DATA16_WRT(g_bBs3CurrentMode)] push xBX ; ; Dispatch the system call. ; cmp ax, BS3_SYSCALL_LAST ja .invalid_syscall %if TMPL_BITS == 16 mov bx, ax shl bx, 1 jmp word [cs:.aoffSyscallHandlers + bx] %else movzx ebx, ax mov ebx, [.aoffSyscallHandlers + ebx * 4] jmp xBX %endif .aoffSyscallHandlers: %ifdef TMPL_16BIT dw .invalid_syscall wrt CGROUP16 dw .print_chr wrt CGROUP16 dw .print_str wrt CGROUP16 dw .to_ringX wrt CGROUP16 dw .to_ringX wrt CGROUP16 dw .to_ringX wrt CGROUP16 dw .to_ringX wrt CGROUP16 dw .restore_ctx wrt CGROUP16 %else dd .invalid_syscall wrt FLAT dd .print_chr wrt FLAT dd .print_str wrt FLAT dd .to_ringX wrt FLAT dd .to_ringX wrt FLAT dd .to_ringX wrt FLAT dd .to_ringX wrt FLAT dd .restore_ctx wrt FLAT %endif ; ; Invalid system call. ; .invalid_syscall: int3 jmp .return ; ; Print char in the CL register. ; ; We use the vga bios teletype interrupt to do the writing, so we must ; be in some kind of real mode for this to work. 16-bit code segment ; requried for the mode switching code. ; BS3_BEGIN_TEXT16 BS3_SET_BITS TMPL_BITS .print_chr: %if TMPL_BITS != 64 push es mov di, ss ; Must save and restore SS for supporting 16/32 and 32/16 caller/kernel ring-0 combinations. %endif %ifndef TMPL_CMN_R86 ; Switch to real mode (20h param scratch area not required). extern TMPL_NM(Bs3SwitchToRM) call TMPL_NM(Bs3SwitchToRM) BS3_SET_BITS 16 %endif ; Print the character, turning '\n' into '\r\n'. cmp cl, 0ah ; \n je .print_chr_newline mov ah, 0eh mov al, cl mov bx, 0ff00h int 10h jmp .print_chr_done .print_chr_newline: mov ax, 0e0dh ; cmd + \r mov bx, 0ff00h int 10h mov ax, 0e0ah ; cmd + \n mov bx, 0ff00h int 10h .print_chr_done: %ifndef TMPL_CMN_R86 ; Switch back (20h param scratch area not required). extern RT_CONCAT3(_Bs3SwitchTo,TMPL_MODE_UNAME,_rm) call RT_CONCAT3(_Bs3SwitchTo,TMPL_MODE_UNAME,_rm) BS3_SET_BITS TMPL_BITS %endif %if TMPL_BITS != 64 mov ss, di pop es %endif jmp .return TMPL_BEGIN_TEXT ; ; Prints DX chars from the string pointed to by CX:xSI to the screen. ; ; We use the vga bios teletype interrupt to do the writing, so we must ; be in some kind of real mode for this to work. The string must be ; accessible from real mode too. ; .print_str: %if TMPL_BITS != 64 push es %endif ; Convert the incoming pointer to real mode (assuming caller checked ; that real mode can access it). call .convert_ptr_arg_to_real_mode_ax_si mov cx, VAR_CALLER_DX ; Switch to real mode (no 20h scratch required) %ifndef TMPL_CMN_R86 %if TMPL_BITS != 16 jmp .print_str_to_16bit BS3_BEGIN_TEXT16 .print_str_to_16bit: BS3_SET_BITS TMPL_BITS %endif extern TMPL_NM(Bs3SwitchToRM) call TMPL_NM(Bs3SwitchToRM) BS3_SET_BITS 16 %endif ; Call code in Bs3PrintStrN to do the work. mov ds, ax call Bs3PrintStrN_c16_CX_Bytes_At_DS_SI ; Switch back (20h param scratch area not required). %ifndef TMPL_CMN_R86 extern RT_CONCAT3(_Bs3SwitchTo,TMPL_MODE_UNAME,_rm) call RT_CONCAT3(_Bs3SwitchTo,TMPL_MODE_UNAME,_rm) %if TMPL_BITS != 16 BS3_SET_BITS TMPL_BITS jmp .print_str_end TMPL_BEGIN_TEXT %endif .print_str_end: %endif %if TMPL_BITS != 64 pop es %endif jmp .return ; ; Switch the caller to ring-0, ring-1, ring-2 or ring-3. ; ; This implement this by saving the entire register context, calling ; a transformation function (C) and restoring the modified register ; context using a generic worker. ; .to_ringX: sub xSP, BS3REGCTX_size mov xBX, xSP ; xBP = BS3REGCTX pointer. call .save_context %if TMPL_BITS == 32 ; Convert xBP to flat pointer in 32-bit push ss push xBX call Bs3SelProtFar32ToFlat32 add sSP, 8 mov xBX, xAX %endif push xBX ; Save pointer for the final restore call. ; Convert the register context from whatever it is to ring-0. BONLY64 sub rsp, 10h mov ax, VAR_CALLER_AX sub ax, BS3_SYSCALL_TO_RING0 push xAX BONLY16 push ss push xBX BS3_CALL Bs3RegCtxConvertToRingX, 2 add xSP, sCB + xCB BS3_ONLY_64BIT(+ 10h) ; Restore the register context (does not return). pop xBX ; restore saved pointer. BONLY64 sub rsp, 18h BONLY16 push ss push xBX BS3_CALL Bs3RegCtxRestore, 1 jmp Bs3Panic ; ; Restore context pointed to by cx:xSI. ; .restore_ctx: call .convert_ptr_arg_to_cx_xSI BONLY64 sub rsp, 10h mov xDX, VAR_CALLER_DX push xDX BONLY16 push cx push xSI BS3_CALL Bs3RegCtxRestore, 2 jmp Bs3Panic ; ; Return. ; .return: pop xBX ; saved mode mov [BS3_DATA16_WRT(g_bBs3CurrentMode)], bl %if TMPL_BITS == 16 and bl, BS3_MODE_CODE_MASK cmp bl, BS3_MODE_CODE_V86 je .return_to_v8086_from_16bit_krnl cmp bl, BS3_MODE_CODE_32 je .return_to_32bit_from_16bit_krnl %if TMPL_MODE == BS3_MODE_RM || TMPL_MODE == BS3_MODE_PE16 cmp byte [BS3_DATA16_WRT(g_uBs3CpuDetected)], BS3CPU_80286 jbe .return_pre_80386 %endif popfd pop esp pop ebp %endif pop sDI pop sSI pop sDX pop sCX pop sAX pop sBX %if TMPL_BITS != 64 pop ds leave iret %else mov es, [rsp+2] mov ds, [rsp] leave ; skips ds iretq %endif %if TMPL_BITS == 16 %if TMPL_MODE == BS3_MODE_RM || TMPL_MODE == BS3_MODE_PE16 ; Variant of the above for 80286 and older. .return_pre_80386: add sp, 0ch pop di pop bx ; dummy pop si pop bx ; dummy pop dx pop bx ; dummy pop cx pop bx ; dummy pop ax pop bx ; dummy pop bx ; pushed twice pop bx pop ds pop bp iret %endif .return_to_v8086_from_16bit_krnl: int3 jmp .return_to_v8086_from_16bit_krnl ; ; Returning to 32-bit code may require us to expand and seed the eip ; and esp addresses in the iret frame since these are truncated when ; using a 16-bit interrupt handler. ; ; Incoming stack: New stack diff cpl: ; bp + 0ah: [ss] ; bp + 08h: [sp] bx + 38h: [ss] New stack same cpl: ; bp + 06h: flags ; bp + 04h: cs bx + 34h: [esp] bx + 30h: eflags ; bp + 02h: ip ; -------------- bx + 30h: eflags bx + 2ch: cs ; bp + 00h: bp ; bp - 02h: ds bx + 2ch: cs bx + 28h: eip ; ------------- ; bp - 06h: ebx bx + 28h: eip bx + 26h: bp ; -------------- bx + 24h: ds ; bp - 0ah: eax bx + 26h: bp ; bx + 24h: ds bx + 20h: ebx ; bp - 0eh: ecx ; bx + 20h: ebx bx + 1ch: eax ; bp - 12h: edx ; bx + 1ch: eax bx + 18h: ecx ; bp - 16h: esi ; bx + 18h: ecx bx + 14h: edx ; bp - 1ah: edi ; bx + 14h: edx bx + 10h: esi ; bp - 1eh: esp ; bx + 10h: esi bx + 0ch: edi ; bp - 22h: ebp ; bx + 0ch: edi bx + 08h: esp ; bp - 26h: eflags ; bx + 08h: esp bx + 04h: ebp ; ; bx + 04h: ebp bx + 00h: eflags ; ; bx + 00h: eflags ; ; ; If we're returning to the same CPL, we're still using the stack of ; the 32-bit caller. The high ESP word does not need restoring. ; ; If we're returning to a lower CPL, there on a 16-bit ring-0 stack, ; however, the high ESP word is still that of the caller. ; .return_to_32bit_from_16bit_krnl: mov ax, cs and al, 3 mov ah, 3 and ah, [xBP + xCB*2] ; The iret frame doubles in size, so allocate more stack. cmp al, ah je .return_to_32bit_from_16bit_krnl_same_cpl_sub_sp sub sp, 2*2 .return_to_32bit_from_16bit_krnl_same_cpl_sub_sp: sub sp, 3*2 mov bx, sp ; Copy the saved registers. xor di, di .return_to_32bit_from_16bit_krnl_copy_loop: mov ecx, [bp + di - 26h] mov [ss:bx + di], ecx add di, 4 cmp di, 28h jb .return_to_32bit_from_16bit_krnl_copy_loop ; Convert the 16-bit iret frame to a 32-bit iret frame. mov ecx, [BS3_DATA16_WRT(g_uBs3TrapEipHint)] mov cx, [bp + 02h] ; ip mov [ss:bx + 28h], ecx mov ecx, 0f00d0000h mov cx, [bp + 04h] ; cs mov [ss:bx + 2ch], ecx mov ecx, [ss:bx] ; caller eflags mov cx, [bp + 06h] ; flags mov [ss:bx + 30h], ecx cmp al, ah jz .return_to_32bit_from_16bit_krnl_do_return mov ecx, [ss:bx + 08h] ; caller esp mov cx, [bp + 08h] ; sp mov [ss:bx + 34h], ecx mov ecx, 0f00d0000h mov cx, [bp + 0ah] ; ss mov [ss:bx + 38h], ecx .return_to_32bit_from_16bit_krnl_do_return: popfd pop ecx ; esp - only the high bits! mov cx, sp mov esp, ecx pop ebp lea bp, [bx + 26h] pop edi pop esi pop edx pop ecx pop eax pop ebx pop ds leave iretd %endif ; 16-bit ; ; Internal function. ss:xBX = Pointer to register frame (BS3REGCTX). ; @uses xAX ; .save_context: %if TMPL_BITS == 16 cmp byte [BS3_DATA16_WRT(g_uBs3CpuDetected)], BS3CPU_80386 jae .save_context_full ; ; 80286 or earlier. ; ; Clear the state area first. push di xor di, di .save_context_16_clear_loop: mov word [ss:bx + di], 0 mov word [ss:bx + di + 2], 0 mov word [ss:bx + di + 4], 0 mov word [ss:bx + di + 6], 0 add di, 8 cmp di, BS3REGCTX_size jb .save_context_16_clear_loop pop di ; Do the 8086/80186/80286 state saving. mov ax, VAR_CALLER_AX mov [ss:bx + BS3REGCTX.rax], ax mov cx, VAR_CALLER_CX mov [ss:bx + BS3REGCTX.rcx], ax mov ax, VAR_CALLER_DX mov [ss:bx + BS3REGCTX.rdx], ax mov ax, VAR_CALLER_BX mov [ss:bx + BS3REGCTX.rbx], ax mov [ss:bx + BS3REGCTX.rsi], si mov [ss:bx + BS3REGCTX.rdi], di mov ax, VAR_CALLER_BP mov [ss:bx + BS3REGCTX.rbp], ax mov ax, VAR_CALLER_DS mov [ss:bx + BS3REGCTX.ds], ax mov [ss:bx + BS3REGCTX.es], es mov ax, [xBP + xCB] mov [ss:bx + BS3REGCTX.rip], ax mov ax, [xBP + xCB*2] mov [ss:bx + BS3REGCTX.cs], ax and al, X86_SEL_RPL mov [ss:bx + BS3REGCTX.bCpl], al cmp al, 0 je .save_context_16_same mov ax, [xBP + xCB*4] mov [ss:bx + BS3REGCTX.rsp], ax mov ax, [xBP + xCB*5] mov [ss:bx + BS3REGCTX.ss], ax jmp .save_context_16_done_stack .save_context_16_same: mov ax, bp add ax, xCB * (1 + 3) mov [ss:bx + BS3REGCTX.rsp], ax mov ax, ss mov [ss:bx + BS3REGCTX.ss], ax .save_context_16_done_stack: mov ax, [xBP + xCB*3] mov [ss:bx + BS3REGCTX.rflags], ax mov al, VAR_CALLER_MODE mov [ss:bx + BS3REGCTX.bMode], al cmp byte [BS3_DATA16_WRT(g_uBs3CpuDetected)], BS3CPU_80286 jne .save_context_16_return smsw [ss:bx + BS3REGCTX.cr0] str [ss:bx + BS3REGCTX.tr] sldt [ss:bx + BS3REGCTX.ldtr] .save_context_16_return: or byte [ss:bx + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_AMD64 | BS3REG_CTX_F_NO_CR4 ret %endif ; TMPL_BITS == 16 ; ; 80386 or later. ; .save_context_full: ; Clear the state area. push xDI xor xDI, xDI AssertCompileSizeAlignment(BS3REGCTX, 16) .save_context_full_clear_loop: %if TMPL_BITS != 64 mov dword [ss:xBX + xDI], 0 mov dword [ss:xBX + xDI + 4], 0 add xDI, 8 %else mov qword [xBX + xDI], 0 mov qword [xBX + xDI + 8], 0 add xDI, 10h %endif cmp xDI, BS3REGCTX_size jb .save_context_full_clear_loop pop xDI ; Do the 386+ state saving. %if TMPL_BITS == 16 ; save the high word of registered pushed on the stack. mov ecx, VAR_CALLER_AX mov [ss:bx + BS3REGCTX.rax], ecx mov ecx, VAR_CALLER_CX mov [ss:bx + BS3REGCTX.rcx], ecx mov ecx, VAR_CALLER_DX mov [ss:bx + BS3REGCTX.rdx], ecx mov ecx, VAR_CALLER_BX mov [ss:bx + BS3REGCTX.rbx], ecx mov ecx, VAR_CALLER_EBP mov [ss:bx + BS3REGCTX.rbp], ecx mov ecx, VAR_CALLER_ESP mov [ss:bx + BS3REGCTX.rsp], ecx mov ecx, VAR_CALLER_SI mov [ss:bx + BS3REGCTX.rsi], ecx mov ecx, VAR_CALLER_DI mov [ss:bx + BS3REGCTX.rdi], ecx mov ecx, VAR_CALLER_EFLAGS mov [ss:bx + BS3REGCTX.rflags], ecx ; Seed high EIP word if 32-bit CS. lar ecx, [bp + 4] jnz .save_context_full_done_16bit_high_word test ecx, X86LAR_F_D jz .save_context_full_done_16bit_high_word mov ecx, [BS3_DATA16_WRT(g_uBs3TrapEipHint)] mov [ss:bx + BS3REGCTX.rip], ecx .save_context_full_done_16bit_high_word: %endif ; 16-bit mov xAX, VAR_CALLER_AX mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rax], xAX mov xCX, VAR_CALLER_CX mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rcx], xCX mov xAX, VAR_CALLER_DX mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rdx], xAX mov xAX, VAR_CALLER_BX mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rbx], xAX mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rsi], sSI mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rdi], sDI mov xAX, VAR_CALLER_BP mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rbp], xAX %if TMPL_BITS != 64 mov ax, VAR_CALLER_DS mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.ds], ax %else mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.ds], ds %endif mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.es], es mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.fs], fs mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.gs], gs mov xAX, [xBP + xCB] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rip], xAX mov ax, [xBP + xCB*2] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.cs], ax %if TMPL_MODE != BS3_MODE_RM and al, X86_SEL_RPL mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.bCpl], al cmp al, 0 je .save_context_full_same mov xAX, [xBP + xCB*4] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rsp], xAX mov ax, [xBP + xCB*5] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.ss], ax jmp .save_context_full_done_stack %else mov byte [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.bCpl], 0 %endif .save_context_full_same: mov xAX, xBP add xAX, xCB * (1 + 3) mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rsp], xAX mov ax, ss mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.ss], ax .save_context_full_done_stack: mov xAX, [xBP + xCB*3] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rflags], xAX mov al, VAR_CALLER_MODE mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.bMode], al %if TMPL_BITS == 64 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r8], r8 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r9], r9 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r10], r10 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r11], r11 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r12], r12 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r13], r13 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r14], r14 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.r15], r15 %endif str [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.tr] sldt [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.ldtr] mov sAX, cr0 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.cr0], sAX mov sAX, cr2 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.cr2], sAX mov sAX, cr3 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.cr3], sAX %if TMPL_BITS != 64 test byte [BS3_DATA16_WRT(g_uBs3CpuDetected)], (BS3CPU_F_CPUID >> 8) jnz .have_cr4 or byte [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_CR4 jmp .done_cr4 .have_cr4: %endif mov sAX, cr4 mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.cr4], sAX %if TMPL_BITS != 64 .done_cr4: or byte [ss:xBX + BS3REGCTX.fbFlags], BS3REG_CTX_F_NO_AMD64 ; Deal with extended v8086 frame. %if TMPL_BITS == 32 test dword [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rflags], X86_EFL_VM jz .save_context_full_return %else test byte VAR_CALLER_MODE, BS3_MODE_CODE_V86 jz .save_context_full_return mov dword [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rflags], X86_EFL_VM %endif mov xAX, [xBP + xCB*4] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.rsp], xAX mov ax, [xBP + xCB*5] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.ss], ax mov ax, [xBP + xCB*6] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.es], ax mov ax, [xBP + xCB*7] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.ds], ax mov ax, [xBP + xCB*8] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.fs], ax mov ax, [xBP + xCB*9] mov [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.gs], ax mov byte [BS3_NOT_64BIT(ss:) xBX + BS3REGCTX.bCpl], 3 jmp .save_context_full_return %endif ; !64-bit .save_context_full_return: ret %if TMPL_BITS == 16 CPU 286 %endif ; ; Internal function for converting a syscall pointer parameter (cx:xSI) ; to a pointer we can use here in this context. ; ; Returns the result in cx:xSI. ; @uses xAX, xCX, xDX ; .convert_ptr_arg_to_cx_xSI: call .convert_ptr_arg_to_flat %if TMPL_BITS == 16 ; Convert to tiled address. mov si, ax ; offset. shl dx, X86_SEL_SHIFT add dx, BS3_SEL_TILED mov cx, dx %else ; Just supply a flat selector. mov xSI, xAX mov cx, ds %endif ret ; ; Internal function for converting a syscall pointer parameter (caller CX:xSI) ; to a real mode pointer. ; ; Returns the result in AX:SI. ; @uses xAX, xCX, xDX ; .convert_ptr_arg_to_real_mode_ax_si: call .convert_ptr_arg_to_flat mov si, ax %if TMPL_BITS == 16 mov ax, dx %else shr eax, 16 %endif shl ax, 12 ret ; ; Internal function for the above that wraps the Bs3SelProtFar32ToFlat32 call. ; ; @returns eax (32-bit, 64-bit), dx+ax (16-bit). ; @uses eax, ecx, edx ; .convert_ptr_arg_to_flat: %if TMPL_BITS == 16 ; Convert to (32-bit) flat address first. test byte VAR_CALLER_MODE, BS3_MODE_CODE_V86 jz .convert_ptr_arg_to_flat_prot_16 mov ax, VAR_CALLER_CX mov dx, ax shl ax, 4 shr dx, 12 add ax, VAR_CALLER_SI adc dx, 0 ret .convert_ptr_arg_to_flat_prot_16: push es push bx push word VAR_CALLER_CX ; selector xor ax, ax test byte VAR_CALLER_MODE, BS3_MODE_CODE_16 jnz .caller_is_16_bit mov ax, VAR_CALLER_SI_HI .caller_is_16_bit: push ax ; offset high push word VAR_CALLER_SI ; offset low call Bs3SelProtFar32ToFlat32 add sp, 2*3 pop bx pop es ret %else ; 32 or 64 bit test byte VAR_CALLER_MODE, BS3_MODE_CODE_V86 jz .convert_ptr_arg_to_cx_xSI_prot ; Convert real mode address to flat address and return it. movzx eax, word VAR_CALLER_CX shl eax, 4 movzx edx, word VAR_CALLER_SI add eax, edx ret ; Convert to (32-bit) flat address. .convert_ptr_arg_to_cx_xSI_prot: %if TMPL_BITS == 64 push r11 push r10 push r9 push r8 sub rsp, 10h %endif movzx ecx, word VAR_CALLER_CX push xCX mov eax, VAR_CALLER_SI test byte VAR_CALLER_MODE, BS3_MODE_CODE_16 jz .no_masking_offset and eax, 0ffffh .no_masking_offset: push xAX BS3_CALL Bs3SelProtFar32ToFlat32,2 add xSP, xCB*2 BS3_ONLY_64BIT(+ 10h) %if TMPL_BITS == 64 pop r8 pop r9 pop r10 pop r11 %endif %endif ret BS3_PROC_END_MODE Bs3TrapSystemCallHandler