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
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_VM86
40 #define SCR_TSS1 (PCB_VM86+4)
52 * vm86_bioscall(struct trapframe_vm86 *vm86)
55 movl vm86pcb,%edx /* scratch data area */
57 movl %eax,SCR_ARGFRAME(%edx) /* save argument pointer */
64 movl PCPU(CURTHREAD),%ecx
65 cmpl %ecx,PCPU(FPCURTHREAD) /* do we need to save fp? */
68 movl TD_PCB(%ecx),%ecx
69 pushl PCB_SAVEFPU(%ecx)
73 popl %edx /* recover our pcb */
75 movl SCR_VMFRAME(%edx),%ebx /* target frame location */
76 movl %ebx,%edi /* destination */
77 movl SCR_ARGFRAME(%edx),%esi /* source (set on entry) */
78 movl $VM86_FRAMESIZE/4,%ecx /* sizeof(struct vm86frame)/4 */
81 movsl /* copy frame to new stack */
83 movl PCPU(CURPCB),%eax
84 pushl %eax /* save curpcb */
85 movl %edx,PCPU(CURPCB) /* set curpcb to vm86pcb */
87 movl PCPU(TSS_GDT),%ebx /* entry in GDT */
89 movl %eax,SCR_TSS0(%edx) /* save first word */
91 andl $~0x200, %eax /* flip 386BSY -> 386TSS */
92 movl %eax,SCR_TSS1(%edx) /* save second word */
94 movl PCB_EXT(%edx),%edi /* vm86 tssd entry */
99 movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
103 pushl %eax /* save address space */
104 movl IdlePTD,%ecx /* va (and pa) of Idle PTD */
107 pushl %eax /* old ptde != 0 when booting */
108 pushl %ebx /* keep for reuse */
110 movl %esp,SCR_STACK(%edx) /* save current stack location */
112 movl SCR_NEWPTD(%edx),%eax /* mapping for vm86 page table */
113 movl %eax,0(%ebx) /* ... install as PTD entry 0 */
115 #if defined(PAE) || defined(PAE_TABLES)
118 movl %ecx,%cr3 /* new page tables */
119 movl SCR_VMFRAME(%edx),%esp /* switch to new stack */
122 movl $vm86_prepcall, %eax
123 call *%eax /* finish setup */
134 * vm86_biosret(struct trapframe_vm86 *vm86)
137 movl vm86pcb,%edx /* data area */
139 movl 4(%esp),%esi /* source */
140 movl SCR_ARGFRAME(%edx),%edi /* destination */
141 movl $VM86_FRAMESIZE/4,%ecx /* size */
144 movsl /* copy frame to original frame */
146 movl SCR_STACK(%edx),%esp /* back to old stack */
147 popl %ebx /* saved va of Idle PTD */
149 movl %eax,0(%ebx) /* restore old pte */
151 movl %eax,%cr3 /* install old page table */
153 movl PCPU(TSS_GDT),%ebx /* entry in GDT */
154 movl SCR_TSS0(%edx),%eax
155 movl %eax,0(%ebx) /* restore first word */
156 movl SCR_TSS1(%edx),%eax
157 movl %eax,4(%ebx) /* restore second word */
158 movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
161 popl PCPU(CURPCB) /* restore curpcb/curproc */
162 movl SCR_ARGFRAME(%edx),%edx /* original stack frame */
163 movl TF_TRAPNO(%edx),%eax /* return (trapno) */
170 ret /* back to our normal program */