vm86bios.s revision 69971
134840Sjlemon/*- 234840Sjlemon * Copyright (c) 1998 Jonathan Lemon 334840Sjlemon * All rights reserved. 434840Sjlemon * 534840Sjlemon * Redistribution and use in source and binary forms, with or without 634840Sjlemon * modification, are permitted provided that the following conditions 734840Sjlemon * are met: 834840Sjlemon * 1. Redistributions of source code must retain the above copyright 934840Sjlemon * notice, this list of conditions and the following disclaimer. 1034840Sjlemon * 2. Redistributions in binary form must reproduce the above copyright 1134840Sjlemon * notice, this list of conditions and the following disclaimer in the 1234840Sjlemon * documentation and/or other materials provided with the distribution. 1334840Sjlemon * 1434840Sjlemon * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1534840Sjlemon * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1634840Sjlemon * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1734840Sjlemon * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1834840Sjlemon * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1934840Sjlemon * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2034840Sjlemon * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2134840Sjlemon * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2234840Sjlemon * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2334840Sjlemon * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2434840Sjlemon * SUCH DAMAGE. 2534840Sjlemon * 2650477Speter * $FreeBSD: head/sys/i386/i386/vm86bios.s 69971 2000-12-13 09:23:53Z jake $ 2734840Sjlemon */ 2834840Sjlemon 2934840Sjlemon#include <machine/asmacros.h> /* miscellaneous asm macros */ 3034840Sjlemon#include <machine/trap.h> 3134840Sjlemon 3234840Sjlemon#include "assym.s" 3334840Sjlemon 3437889Sjlemon#define SCR_NEWPTD PCB_ESI /* readability macros */ 3537889Sjlemon#define SCR_VMFRAME PCB_EBP /* see vm86.c for explanation */ 3637889Sjlemon#define SCR_STACK PCB_ESP 3737889Sjlemon#define SCR_PGTABLE PCB_EBX 3837889Sjlemon#define SCR_ARGFRAME PCB_EIP 3946129Sluoqi#define SCR_TSS0 PCB_SPARE 4046129Sluoqi#define SCR_TSS1 (PCB_SPARE+4) 4137889Sjlemon 4234840Sjlemon .data 4334840Sjlemon ALIGN_DATA 4434840Sjlemon 4534840Sjlemon .globl _in_vm86call, _vm86pcb 4634840Sjlemon 4734840Sjlemon_in_vm86call: .long 0 4834840Sjlemon_vm86pcb: .long 0 4934840Sjlemon 5034840Sjlemon .text 5134840Sjlemon 5234840Sjlemon/* 5334840Sjlemon * vm86_bioscall(struct trapframe_vm86 *vm86) 5434840Sjlemon */ 5534840SjlemonENTRY(vm86_bioscall) 5637889Sjlemon movl _vm86pcb,%edx /* scratch data area */ 5734840Sjlemon movl 4(%esp),%eax 5837889Sjlemon movl %eax,SCR_ARGFRAME(%edx) /* save argument pointer */ 5934840Sjlemon pushl %ebx 6034840Sjlemon pushl %ebp 6134840Sjlemon pushl %esi 6234840Sjlemon pushl %edi 6334840Sjlemon pushl %gs 6434840Sjlemon 6534840Sjlemon#if NNPX > 0 6669971Sjake movl PCPU(CURPROC),%ecx 6769971Sjake cmpl %ecx,PCPU(NPXPROC) /* do we need to save fp? */ 6834840Sjlemon jne 1f 6939872Sjlemon testl %ecx,%ecx 7039872Sjlemon je 1f /* no curproc/npxproc */ 7139046Syokota pushl %edx 7234840Sjlemon movl P_ADDR(%ecx),%ecx 7334840Sjlemon addl $PCB_SAVEFPU,%ecx 7439046Syokota pushl %ecx 7534840Sjlemon call _npxsave 7639046Syokota popl %ecx 7734840Sjlemon popl %edx /* recover our pcb */ 7834840Sjlemon#endif 7934840Sjlemon 8034840Sjlemon1: 8137889Sjlemon movl SCR_VMFRAME(%edx),%ebx /* target frame location */ 8234840Sjlemon movl %ebx,%edi /* destination */ 8337889Sjlemon movl SCR_ARGFRAME(%edx),%esi /* source (set on entry) */ 8447080Sluoqi movl $VM86_FRAMESIZE/4,%ecx /* sizeof(struct vm86frame)/4 */ 8534840Sjlemon cld 8634840Sjlemon rep 8734840Sjlemon movsl /* copy frame to new stack */ 8834840Sjlemon 8969971Sjake movl PCPU(CURPCB),%eax 9034840Sjlemon pushl %eax /* save curpcb */ 9169971Sjake movl %edx,PCPU(CURPCB) /* set curpcb to vm86pcb */ 9234840Sjlemon 9369971Sjake movl PCPU(TSS_GDT),%ebx /* entry in GDT */ 9434840Sjlemon movl 0(%ebx),%eax 9537889Sjlemon movl %eax,SCR_TSS0(%edx) /* save first word */ 9634840Sjlemon movl 4(%ebx),%eax 9734840Sjlemon andl $~0x200, %eax /* flip 386BSY -> 386TSS */ 9837889Sjlemon movl %eax,SCR_TSS1(%edx) /* save second word */ 9934840Sjlemon 10034840Sjlemon movl PCB_EXT(%edx),%edi /* vm86 tssd entry */ 10134840Sjlemon movl 0(%edi),%eax 10234840Sjlemon movl %eax,0(%ebx) 10334840Sjlemon movl 4(%edi),%eax 10434840Sjlemon movl %eax,4(%ebx) 10547081Sluoqi movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */ 10634840Sjlemon ltr %si 10734840Sjlemon 10834840Sjlemon movl %cr3,%eax 10934840Sjlemon pushl %eax /* save address space */ 11034840Sjlemon movl _IdlePTD,%ecx 11134840Sjlemon movl %ecx,%ebx 11234840Sjlemon addl $KERNBASE,%ebx /* va of Idle PTD */ 11334840Sjlemon movl 0(%ebx),%eax 11434840Sjlemon pushl %eax /* old ptde != 0 when booting */ 11534840Sjlemon pushl %ebx /* keep for reuse */ 11634840Sjlemon 11737889Sjlemon movl %esp,SCR_STACK(%edx) /* save current stack location */ 11834840Sjlemon 11937889Sjlemon movl SCR_NEWPTD(%edx),%eax /* mapping for vm86 page table */ 12034840Sjlemon movl %eax,0(%ebx) /* ... install as PTD entry 0 */ 12134840Sjlemon 12234840Sjlemon movl %ecx,%cr3 /* new page tables */ 12337889Sjlemon movl SCR_VMFRAME(%edx),%esp /* switch to new stack */ 12434840Sjlemon 12534840Sjlemon call _vm86_prepcall /* finish setup */ 12634840Sjlemon 12734840Sjlemon movl $1,_in_vm86call /* set flag for trap() */ 12834840Sjlemon 12934840Sjlemon /* 13034840Sjlemon * Return via _doreti 13134840Sjlemon */ 13269971Sjake incb PCPU(INTR_NESTING_LEVEL) 13334840Sjlemon MEXITCOUNT 13434840Sjlemon jmp _doreti 13534840Sjlemon 13634840Sjlemon 13734840Sjlemon/* 13834840Sjlemon * vm86_biosret(struct trapframe_vm86 *vm86) 13934840Sjlemon */ 14034840SjlemonENTRY(vm86_biosret) 14134840Sjlemon movl _vm86pcb,%edx /* data area */ 14234840Sjlemon 14334840Sjlemon movl 4(%esp),%esi /* source */ 14437889Sjlemon movl SCR_ARGFRAME(%edx),%edi /* destination */ 14547080Sluoqi movl $VM86_FRAMESIZE/4,%ecx /* size */ 14634840Sjlemon cld 14734840Sjlemon rep 14834840Sjlemon movsl /* copy frame to original frame */ 14934840Sjlemon 15037889Sjlemon movl SCR_STACK(%edx),%esp /* back to old stack */ 15134840Sjlemon popl %ebx /* saved va of Idle PTD */ 15234840Sjlemon popl %eax 15334840Sjlemon movl %eax,0(%ebx) /* restore old pte */ 15434840Sjlemon popl %eax 15534840Sjlemon movl %eax,%cr3 /* install old page table */ 15634840Sjlemon 15734840Sjlemon movl $0,_in_vm86call /* reset trapflag */ 15834840Sjlemon 15969971Sjake movl PCPU(TSS_GDT),%ebx /* entry in GDT */ 16037889Sjlemon movl SCR_TSS0(%edx),%eax 16134840Sjlemon movl %eax,0(%ebx) /* restore first word */ 16237889Sjlemon movl SCR_TSS1(%edx),%eax 16334840Sjlemon movl %eax,4(%ebx) /* restore second word */ 16447081Sluoqi movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */ 16534840Sjlemon ltr %si 16634840Sjlemon 16769971Sjake popl PCPU(CURPCB) /* restore curpcb/curproc */ 16837889Sjlemon movl SCR_ARGFRAME(%edx),%edx /* original stack frame */ 16934840Sjlemon movl TF_TRAPNO(%edx),%eax /* return (trapno) */ 17034840Sjlemon 17134840Sjlemon popl %gs 17234840Sjlemon popl %edi 17334840Sjlemon popl %esi 17434840Sjlemon popl %ebp 17534840Sjlemon popl %ebx 17634840Sjlemon ret /* back to our normal program */ 177