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
31 #include <machine/asmacros.h> /* miscellaneous asm macros */
32 #include <machine/trap.h>
36 #define SCR_NEWPTD PCB_ESI /* readability macros */
37 #define SCR_VMFRAME PCB_EBP /* see vm86.c for explanation */
38 #define SCR_STACK PCB_ESP
39 #define SCR_PGTABLE PCB_EBX
40 #define SCR_ARGFRAME PCB_EIP
41 #define SCR_TSS0 PCB_VM86
42 #define SCR_TSS1 (PCB_VM86+4)
54 * vm86_bioscall(struct trapframe_vm86 *vm86)
57 movl vm86pcb,%edx /* scratch data area */
59 movl %eax,SCR_ARGFRAME(%edx) /* save argument pointer */
69 movl PCPU(CURTHREAD),%ecx
70 cmpl %ecx,PCPU(FPCURTHREAD) /* do we need to save fp? */
73 je 1f /* no curproc/npxproc */
75 movl TD_PCB(%ecx),%ecx
76 pushl PCB_SAVEFPU(%ecx)
79 popl %edx /* recover our pcb */
84 movl SCR_VMFRAME(%edx),%ebx /* target frame location */
85 movl %ebx,%edi /* destination */
86 movl SCR_ARGFRAME(%edx),%esi /* source (set on entry) */
87 movl $VM86_FRAMESIZE/4,%ecx /* sizeof(struct vm86frame)/4 */
90 movsl /* copy frame to new stack */
92 movl PCPU(CURPCB),%eax
93 pushl %eax /* save curpcb */
94 movl %edx,PCPU(CURPCB) /* set curpcb to vm86pcb */
96 movl PCPU(TSS_GDT),%ebx /* entry in GDT */
98 movl %eax,SCR_TSS0(%edx) /* save first word */
100 andl $~0x200, %eax /* flip 386BSY -> 386TSS */
101 movl %eax,SCR_TSS1(%edx) /* save second word */
103 movl PCB_EXT(%edx),%edi /* vm86 tssd entry */
108 movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
112 pushl %eax /* save address space */
115 addl $KERNBASE,%ebx /* va of Idle PTD */
117 pushl %eax /* old ptde != 0 when booting */
118 pushl %ebx /* keep for reuse */
120 movl %esp,SCR_STACK(%edx) /* save current stack location */
122 movl SCR_NEWPTD(%edx),%eax /* mapping for vm86 page table */
123 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 */
132 call vm86_prepcall /* finish setup */
143 * vm86_biosret(struct trapframe_vm86 *vm86)
146 movl vm86pcb,%edx /* data area */
148 movl 4(%esp),%esi /* source */
149 movl SCR_ARGFRAME(%edx),%edi /* destination */
150 movl $VM86_FRAMESIZE/4,%ecx /* size */
153 movsl /* copy frame to original frame */
155 movl SCR_STACK(%edx),%esp /* back to old stack */
156 popl %ebx /* saved va of Idle PTD */
158 movl %eax,0(%ebx) /* restore old pte */
160 movl %eax,%cr3 /* install old page table */
162 movl PCPU(TSS_GDT),%ebx /* entry in GDT */
163 movl SCR_TSS0(%edx),%eax
164 movl %eax,0(%ebx) /* restore first word */
165 movl SCR_TSS1(%edx),%eax
166 movl %eax,4(%ebx) /* restore second word */
167 movl $GPROC0_SEL*8,%esi /* GSEL(entry, SEL_KPL) */
170 popl PCPU(CURPCB) /* restore curpcb/curproc */
171 movl SCR_ARGFRAME(%edx),%edx /* original stack frame */
172 movl TF_TRAPNO(%edx),%eax /* return (trapno) */
179 ret /* back to our normal program */