regress/sys/arch/i386/vm86/vm86test.c

   1 /* $NetBSD: vm86test.c,v 1.2 2003/09/10 15:33:08 drochner Exp $ */
   2
   3 /*
   4  * Copyright (c) 2003
   5  *      Matthias Drochner.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions, and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/types.h>
  30 #include <signal.h>
  31 #include <ucontext.h>
  32 #include <machine/segments.h>
  33 #include <machine/sysarch.h>
  34 #include <machine/vm86.h>
  35 #include <sys/mman.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <err.h>
  40
  41 void urghdl(int, siginfo_t *, void *);
  42
  43 /*
  44  * Some code to execute in vm86 mode. Uses INT 0x20 to print some status info
  45  * and INT 0x21 to exit.
  46  * We don't use an IDT, so the interrupts must be vectored to the user task.
  47  */
  48 const char vmcode[] = {
  49         0xcd, /* INTxx */
  50         0x20,
  51         0xfb, /* STI */
  52         0xcd, /* INTxx */
  53         0x20,
  54         0xfa, /* CLI */
  55         0xcd, /* INTxx */
  56         0x21,
  57 };
  58
  59 /*
  60  * XXX before our text segment, must be below 1M to be addressable.
  61  * Also chosen to start >=64k, to catch the longstanding kernel bug which
  62  * caused the stack segment to be ignored in the !SA_ONSTACK case.
  63  */
  64 #define VMCODEBASE (void *)0x80000
  65 #define VMSIZE 0x4000
  66
  67 void
  68 urghdl(int sig, siginfo_t *si, void *vuc)
  69 {
  70         stack_t oss;
  71         ucontext_t *uc = vuc;
  72         int res, ip, eflags, code;
  73
  74         ip = uc->uc_mcontext.__gregs[_REG_EIP];
  75         eflags = uc->uc_mcontext.__gregs[_REG_EFL];
  76         code = si->si_trap;
  77
  78         res = sigaltstack(0, &oss);
  79         if (res < 0)
  80                 err(6, "sigaltstack in handler");
  81         fprintf(stderr, "urghdl called @ip=%04x, code=%04x, ", ip, code);
  82         fprintf(stderr, "eflags=%08x, stackflags=%01x\n",
  83                 eflags, oss.ss_flags);
  84         if (code == VM86_MAKEVAL(VM86_INTx, 0x21))
  85                 exit (0);
  86 }
  87
  88 struct vm86_struct vm; /* zero inited */
  89
  90 int
  91 main(int argc, char **argv)
  92 {
  93         void *mapaddr;
  94         unsigned int codeaddr;
  95         struct sigaction sa;
  96         int usealtstack, res;
  97         stack_t ss;
  98
  99         usealtstack = 0;
 100         if (argc > 1)
 101                 usealtstack = 1;
 102
 103         mapaddr = mmap(VMCODEBASE, VMSIZE, PROT_READ|PROT_WRITE|PROT_EXEC,
 104                        MAP_ANON|MAP_FIXED, -1, 0);
 105         if (mapaddr == (void *)-1)
 106                 err(1, "mmap");
 107
 108         memcpy(mapaddr, vmcode, sizeof(vmcode));
 109
 110         codeaddr = (unsigned int)mapaddr;
 111         vm.substr.regs[_REG_CS] = codeaddr >> 4;
 112         vm.substr.regs[_REG_EIP] = codeaddr & 15; /* unnecessary here */
 113         vm.substr.ss_cpu_type = VCPU_586;
 114         vm.int_byuser[4] = 0x03; /* vector INT 0x20 and 0x21 */
 115
 116         if (usealtstack) {
 117                 ss.ss_sp = malloc(SIGSTKSZ);
 118                 ss.ss_size = SIGSTKSZ;
 119                 ss.ss_flags = 0;
 120                 res = sigaltstack(&ss, 0);
 121                 if (res < 0)
 122                         err (2, "sigaltstack");
 123         } else {
 124                 vm.substr.regs[_REG_SS] = codeaddr >> 4;
 125                 vm.substr.regs[_REG_ESP] = VMSIZE - (codeaddr & 15); /* hmm */
 126         }
 127
 128         sa.sa_sigaction = urghdl;
 129         sigemptyset(&sa.sa_mask);
 130         sa.sa_flags = SA_SIGINFO | (usealtstack ? SA_ONSTACK : 0);
 131         res = sigaction(SIGURG, &sa, 0);
 132         if (res < 0)
 133                 err(3, "sigaction");
 134
 135         res = i386_vm86(&vm);
 136         if (res < 0)
 137                 err(4, "vm86");
 138
 139         /* NOTREACHED */
 140         exit (5);
 141 }