142 lines
4.0 KiB
C
142 lines
4.0 KiB
C
/* $NetBSD: vm86test.c,v 1.3 2003/09/11 19:14:01 christos Exp $ */
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/*
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* Copyright (c) 2003
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* Matthias Drochner. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <signal.h>
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#include <ucontext.h>
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#include <machine/segments.h>
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#include <machine/sysarch.h>
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#include <machine/vm86.h>
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#include <sys/mman.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <err.h>
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void urghdl(int, siginfo_t *, void *);
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/*
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* Some code to execute in vm86 mode. Uses INT 0x20 to print some status info
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* and INT 0x21 to exit.
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* We don't use an IDT, so the interrupts must be vectored to the user task.
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*/
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const char vmcode[] = {
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0xcd, /* INTxx */
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0x20,
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0xfb, /* STI */
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0xcd, /* INTxx */
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0x20,
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0xfa, /* CLI */
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0xcd, /* INTxx */
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0x21,
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};
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/*
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* XXX before our text segment, must be below 1M to be addressable.
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* Also chosen to start >=64k, to catch the longstanding kernel bug which
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* caused the stack segment to be ignored in the !SA_ONSTACK case.
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*/
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#define VMCODEBASE (void *)0x80000
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#define VMSIZE 0x4000
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void
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urghdl(int sig, siginfo_t *si, void *vuc)
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{
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stack_t oss;
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ucontext_t *uc = vuc;
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int res, ip, eflags, code;
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ip = uc->uc_mcontext.__gregs[_REG_EIP];
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eflags = uc->uc_mcontext.__gregs[_REG_EFL];
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code = si->si_trap;
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res = sigaltstack(0, &oss);
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if (res < 0)
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err(6, "sigaltstack in handler");
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fprintf(stderr, "urghdl called @ip=%04x, code=%04x, ", ip, code);
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fprintf(stderr, "eflags=%08x, stackflags=%01x\n",
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eflags, oss.ss_flags);
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if (code == VM86_MAKEVAL(VM86_INTx, 0x21))
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exit (0);
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}
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struct vm86_struct vm; /* zero inited */
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int
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main(int argc, char **argv)
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{
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void *mapaddr;
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unsigned int codeaddr;
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struct sigaction sa;
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int usealtstack, res;
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stack_t ss;
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usealtstack = 0;
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if (argc > 1)
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usealtstack = 1;
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mapaddr = mmap(VMCODEBASE, VMSIZE, PROT_READ|PROT_WRITE|PROT_EXEC,
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MAP_ANON|MAP_FIXED, -1, 0);
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if (mapaddr == (void *)-1)
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err(1, "mmap");
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memcpy(mapaddr, vmcode, sizeof(vmcode));
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codeaddr = (unsigned int)mapaddr;
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vm.substr.regs[_REG_CS] = codeaddr >> 4;
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vm.substr.regs[_REG_EIP] = codeaddr & 15; /* unnecessary here */
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vm.substr.ss_cpu_type = VCPU_586;
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vm.int_byuser[4] = 0x03; /* vector INT 0x20 and 0x21 */
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if (usealtstack) {
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ss.ss_sp = malloc(SIGSTKSZ);
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ss.ss_size = SIGSTKSZ;
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ss.ss_flags = 0;
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res = sigaltstack(&ss, 0);
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if (res < 0)
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err (2, "sigaltstack");
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} else {
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vm.substr.regs[_REG_SS] = codeaddr >> 4;
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vm.substr.regs[_REG_ESP] = VMSIZE - (codeaddr & 15); /* hmm */
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}
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sa.sa_sigaction = urghdl;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_SIGINFO | (usealtstack ? SA_ONSTACK : 0);
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res = sigaction(SIGURG, &sa, 0);
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if (res < 0)
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err(3, "sigaction");
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res = i386_vm86(&vm);
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if (res < 0)
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err(4, "vm86");
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/* NOTREACHED */
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exit (5);
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}
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