/*-
* Copyright (c) 1998 Jonathan Lemon
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <machine/asmacros.h> /* miscellaneous asm macros */
#include <machine/trap.h>
#include "assym.inc"
#define SCR_NEWPTD PCB_ESI /* readability macros */
#define SCR_VMFRAME PCB_EBP /* see vm86.c for explanation */
#define SCR_STACK PCB_ESP
#define SCR_PGTABLE PCB_EBX
#define SCR_ARGFRAME PCB_EIP
#define SCR_TSS0 PCB_VM86
#define SCR_TSS1 (PCB_VM86+4)
.data
ALIGN_DATA
.globl vm86pcb
vm86pcb: .long 0
.text
/*
* vm86_bioscall(struct trapframe_vm86 *vm86)
*/
ENTRY(vm86_bioscall)
movl vm86pcb,%edx /* scratch data area */
movl 4(%esp),%eax
movl %eax,SCR_ARGFRAME(%edx) /* save argument pointer */
pushl %ebx
pushl %ebp
pushl %esi
pushl %edi
pushl %gs
movl PCPU(CURTHREAD),%ecx
cmpl %ecx,PCPU(FPCURTHREAD) /* do we need to save fp? */
jne 1f
pushl %edx
movl TD_PCB(%ecx),%ecx
pushl PCB_SAVEFPU(%ecx)
movl $npxsave,%eax
call *%eax
addl $4,%esp
popl %edx /* recover our pcb */
1:
movl SCR_VMFRAME(%edx),%ebx /* target frame location */
movl %ebx,%edi /* destination */
movl SCR_ARGFRAME(%edx),%esi /* source (set on entry) */
movl $VM86_FRAMESIZE/4,%ecx /* sizeof(struct vm86frame)/4 */
cld
rep
movsl /* copy frame to new stack */
movl PCPU(CURPCB),%eax
pushl %eax /* save curpcb */
movl %edx,PCPU(CURPCB) /* set curpcb to vm86pcb */
movl PCPU(TSS_GDT),%ebx /* entry in GDT */
movl 0(%ebx),%eax
movl %eax,SCR_TSS0(%edx) /* save first word */
movl 4(%ebx),%eax
andl $~0x200, %eax /* flip 386BSY -> 386TSS */
movl %eax,SCR_TSS1(%edx) /* save second word */
movl PCB_EXT(%edx),%edi /* vm86 tssd entry */
movl 0(%edi),%eax
movl %eax,0(%ebx)
movl 4(%edi),%eax
movl %eax,4(%ebx)
movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
ltr %si
movl %cr3,%eax
pushl %eax /* save address space */
cmpb $0,pae_mode
jne 2f
movl IdlePTD_nopae,%ecx /* va (and pa) of Idle PTD */
jmp 3f
2: movl IdlePTD_pae,%ecx
3: movl %ecx,%ebx
movl 0(%ebx),%eax
pushl %eax /* old ptde != 0 when booting */
pushl %ebx /* keep for reuse */
movl %esp,SCR_STACK(%edx) /* save current stack location */
movl SCR_NEWPTD(%edx),%eax /* mapping for vm86 page table */
movl %eax,0(%ebx) /* ... install as PTD entry 0 */
cmpb $0,pae_mode
je 4f
movl IdlePDPT,%ecx
4: movl %ecx,%cr3 /* new page tables */
movl SCR_VMFRAME(%edx),%esp /* switch to new stack */
pushl %esp
movl $vm86_prepcall, %eax
call *%eax /* finish setup */
add $4, %esp
/*
* Return via doreti
*/
jmp doreti
/*
* vm86_biosret(struct trapframe_vm86 *vm86)
*/
ENTRY(vm86_biosret)
movl vm86pcb,%edx /* data area */
movl 4(%esp),%esi /* source */
movl SCR_ARGFRAME(%edx),%edi /* destination */
movl $VM86_FRAMESIZE/4,%ecx /* size */
cld
rep
movsl /* copy frame to original frame */
movl SCR_STACK(%edx),%esp /* back to old stack */
popl %ebx /* saved va of Idle PTD */
popl %eax
movl %eax,0(%ebx) /* restore old pte */
popl %eax
movl %eax,%cr3 /* install old page table */
movl PCPU(TSS_GDT),%ebx /* entry in GDT */
movl SCR_TSS0(%edx),%eax
movl %eax,0(%ebx) /* restore first word */
movl SCR_TSS1(%edx),%eax
movl %eax,4(%ebx) /* restore second word */
movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
ltr %si
popl PCPU(CURPCB) /* restore curpcb/curproc */
movl SCR_ARGFRAME(%edx),%edx /* original stack frame */
movl TF_TRAPNO(%edx),%eax /* return (trapno) */
popl %gs
popl %edi
popl %esi
popl %ebp
popl %ebx
ret /* back to our normal program */
