2 * Copyright (c) 1998 Jonathan Lemon
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/sys/i386/i386/vm86bios.s,v 1.15.2.1 2000/05/16 06:58:07 dillon Exp $
29 #include <machine/asmacros.h> /* miscellaneous asm macros */
30 #include <machine/trap.h>
34 #define SCR_NEWPTD PCB_ESI /* readability macros */
35 #define SCR_VMFRAME PCB_EBP /* see vm86.c for explanation */
36 #define SCR_STACK PCB_ESP
37 #define SCR_PGTABLE PCB_EBX
38 #define SCR_ARGFRAME PCB_EIP
39 #define SCR_TSS0 PCB_SPARE
40 #define SCR_TSS1 (PCB_SPARE+4)
45 .globl _in_vm86call, _vm86pcb
53 * vm86_bioscall(struct trapframe_vm86 *vm86)
56 movl _vm86pcb,%edx /* scratch data area */
58 movl %eax,SCR_ARGFRAME(%edx) /* save argument pointer */
67 MP_LOCK /* Get global lock */
73 cmpl %ecx,_npxproc /* do we need to save fp? */
76 je 1f /* no curproc/npxproc */
78 movl P_ADDR(%ecx),%ecx
79 addl $PCB_SAVEFPU,%ecx
83 popl %edx /* recover our pcb */
87 movl SCR_VMFRAME(%edx),%ebx /* target frame location */
88 movl %ebx,%edi /* destination */
89 movl SCR_ARGFRAME(%edx),%esi /* source (set on entry) */
90 movl $VM86_FRAMESIZE/4,%ecx /* sizeof(struct vm86frame)/4 */
93 movsl /* copy frame to new stack */
96 pushl %eax /* save curpcb */
97 movl %edx,_curpcb /* set curpcb to vm86pcb */
99 movl _tss_gdt,%ebx /* entry in GDT */
101 movl %eax,SCR_TSS0(%edx) /* save first word */
103 andl $~0x200, %eax /* flip 386BSY -> 386TSS */
104 movl %eax,SCR_TSS1(%edx) /* save second word */
106 movl PCB_EXT(%edx),%edi /* vm86 tssd entry */
111 movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
115 pushl %eax /* save address space */
118 addl $KERNBASE,%ebx /* va of Idle PTD */
120 pushl %eax /* old ptde != 0 when booting */
121 pushl %ebx /* keep for reuse */
123 movl %esp,SCR_STACK(%edx) /* save current stack location */
125 movl SCR_NEWPTD(%edx),%eax /* mapping for vm86 page table */
126 movl %eax,0(%ebx) /* ... install as PTD entry 0 */
128 movl %ecx,%cr3 /* new page tables */
129 movl SCR_VMFRAME(%edx),%esp /* switch to new stack */
131 call _vm86_prepcall /* finish setup */
133 movl $1,_in_vm86call /* set flag for trap() */
139 pushl _cpl /* cpl to restore */
141 pushl _cpl /* cpl to restore */
143 subl $4,%esp /* dummy unit */
144 incb _intr_nesting_level
150 * vm86_biosret(struct trapframe_vm86 *vm86)
153 movl _vm86pcb,%edx /* data area */
155 movl 4(%esp),%esi /* source */
156 movl SCR_ARGFRAME(%edx),%edi /* destination */
157 movl $VM86_FRAMESIZE/4,%ecx /* size */
160 movsl /* copy frame to original frame */
162 movl SCR_STACK(%edx),%esp /* back to old stack */
163 popl %ebx /* saved va of Idle PTD */
165 movl %eax,0(%ebx) /* restore old pte */
167 movl %eax,%cr3 /* install old page table */
169 movl $0,_in_vm86call /* reset trapflag */
171 movl _tss_gdt,%ebx /* entry in GDT */
172 movl SCR_TSS0(%edx),%eax
173 movl %eax,0(%ebx) /* restore first word */
174 movl SCR_TSS1(%edx),%eax
175 movl %eax,4(%ebx) /* restore second word */
176 movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
179 popl _curpcb /* restore curpcb/curproc */
180 movl SCR_ARGFRAME(%edx),%edx /* original stack frame */
181 movl TF_TRAPNO(%edx),%eax /* return (trapno) */
188 ret /* back to our normal program */