linux-user/main.c

   1 /*
   2  *  gemu main
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 #include <stdlib.h>
  21 #include <stdio.h>
  22 #include <stdarg.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26
  27 #include "gemu.h"
  28
  29 #include "cpu-i386.h"
  30
  31 #define DEBUG_LOGFILE "/tmp/gemu.log"
  32
  33 FILE *logfile = NULL;
  34 int loglevel;
  35
  36 unsigned long x86_stack_size;
  37 unsigned long stktop;
  38
  39 void gemu_log(const char *fmt, ...)
  40 {
  41     va_list ap;
  42
  43     va_start(ap, fmt);
  44     vfprintf(stderr, fmt, ap);
  45     va_end(ap);
  46 }
  47
  48 /***********************************************************/
  49 /* CPUX86 core interface */
  50
  51 void cpu_x86_outb(int addr, int val)
  52 {
  53     fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);
  54 }
  55
  56 void cpu_x86_outw(int addr, int val)
  57 {
  58     fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);
  59 }
  60
  61 void cpu_x86_outl(int addr, int val)
  62 {
  63     fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
  64 }
  65
  66 int cpu_x86_inb(int addr)
  67 {
  68     fprintf(stderr, "inb: port=0x%04x\n", addr);
  69     return 0;
  70 }
  71
  72 int cpu_x86_inw(int addr)
  73 {
  74     fprintf(stderr, "inw: port=0x%04x\n", addr);
  75     return 0;
  76 }
  77
  78 int cpu_x86_inl(int addr)
  79 {
  80     fprintf(stderr, "inl: port=0x%04x\n", addr);
  81     return 0;
  82 }
  83
  84 void write_dt(void *ptr, unsigned long addr, unsigned long limit,
  85               int seg32_bit)
  86 {
  87     unsigned int e1, e2, limit_in_pages;
  88     limit_in_pages = 0;
  89     if (limit > 0xffff) {
  90         limit = limit >> 12;
  91         limit_in_pages = 1;
  92     }
  93     e1 = (addr << 16) | (limit & 0xffff);
  94     e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);
  95     e2 |= limit_in_pages << 23; /* byte granularity */
  96     e2 |= seg32_bit << 22; /* 32 bit segment */
  97     stl((uint8_t *)ptr, e1);
  98     stl((uint8_t *)ptr + 4, e2);
  99 }
 100
 101 uint64_t gdt_table[6];
 102
 103 void cpu_loop(struct CPUX86State *env)
 104 {
 105     for(;;) {
 106         int err;
 107         uint8_t *pc;
 108
 109         err = cpu_x86_exec(env);
 110         pc = env->seg_cache[R_CS].base + env->eip;
 111         switch(err) {
 112         case EXCP0D_GPF:
 113             if (pc[0] == 0xcd && pc[1] == 0x80) {
 114                 /* syscall */
 115                 env->eip += 2;
 116                 env->regs[R_EAX] = do_syscall(env,
 117                                               env->regs[R_EAX],
 118                                               env->regs[R_EBX],
 119                                               env->regs[R_ECX],
 120                                               env->regs[R_EDX],
 121                                               env->regs[R_ESI],
 122                                               env->regs[R_EDI],
 123                                               env->regs[R_EBP]);
 124             } else {
 125                 goto trap_error;
 126             }
 127             break;
 128         default:
 129         trap_error:
 130             fprintf(stderr, "0x%08lx: Unknown exception %d, aborting\n",
 131                     (long)pc, err);
 132             abort();
 133         }
 134         process_pending_signals(env);
 135     }
 136 }
 137
 138 void usage(void)
 139 {
 140     printf("gemu version " GEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"
 141            "usage: gemu [-d] program [arguments...]\n"
 142            "Linux x86 emulator\n"
 143            );
 144     exit(1);
 145 }
 146
 147 int main(int argc, char **argv)
 148 {
 149     const char *filename;
 150     struct target_pt_regs regs1, *regs = &regs1;
 151     struct image_info info1, *info = &info1;
 152     CPUX86State *env;
 153     int optind;
 154
 155     if (argc <= 1)
 156         usage();
 157     loglevel = 0;
 158     optind = 1;
 159     if (argv[optind] && !strcmp(argv[optind], "-d")) {
 160         loglevel = 1;
 161         optind++;
 162     }
 163     filename = argv[optind];
 164
 165     /* init debug */
 166     if (loglevel) {
 167         logfile = fopen(DEBUG_LOGFILE, "w");
 168         if (!logfile) {
 169             perror(DEBUG_LOGFILE);
 170             exit(1);
 171         }
 172         setvbuf(logfile, NULL, _IOLBF, 0);
 173     }
 174
 175     /* Zero out regs */
 176     memset(regs, 0, sizeof(struct target_pt_regs));
 177
 178     /* Zero out image_info */
 179     memset(info, 0, sizeof(struct image_info));
 180
 181     if(elf_exec(filename, argv+optind, environ, regs, info) != 0) {
 182         printf("Error loading %s\n", filename);
 183         exit(1);
 184     }
 185
 186     if (loglevel) {
 187         fprintf(logfile, "start_brk   0x%08lx\n" , info->start_brk);
 188         fprintf(logfile, "end_code    0x%08lx\n" , info->end_code);
 189         fprintf(logfile, "start_code  0x%08lx\n" , info->start_code);
 190         fprintf(logfile, "end_data    0x%08lx\n" , info->end_data);
 191         fprintf(logfile, "start_stack 0x%08lx\n" , info->start_stack);
 192         fprintf(logfile, "brk         0x%08lx\n" , info->brk);
 193         fprintf(logfile, "esp         0x%08lx\n" , regs->esp);
 194         fprintf(logfile, "eip         0x%08lx\n" , regs->eip);
 195     }
 196
 197     target_set_brk((char *)info->brk);
 198     syscall_init();
 199     signal_init();
 200
 201     env = cpu_x86_init();
 202
 203     /* linux register setup */
 204     env->regs[R_EAX] = regs->eax;
 205     env->regs[R_EBX] = regs->ebx;
 206     env->regs[R_ECX] = regs->ecx;
 207     env->regs[R_EDX] = regs->edx;
 208     env->regs[R_ESI] = regs->esi;
 209     env->regs[R_EDI] = regs->edi;
 210     env->regs[R_EBP] = regs->ebp;
 211     env->regs[R_ESP] = regs->esp;
 212     env->eip = regs->eip;
 213
 214     /* linux segment setup */
 215     env->gdt.base = (void *)gdt_table;
 216     env->gdt.limit = sizeof(gdt_table) - 1;
 217     write_dt(&gdt_table[__USER_CS >> 3], 0, 0xffffffff, 1);
 218     write_dt(&gdt_table[__USER_DS >> 3], 0, 0xffffffff, 1);
 219     cpu_x86_load_seg(env, R_CS, __USER_CS);
 220     cpu_x86_load_seg(env, R_DS, __USER_DS);
 221     cpu_x86_load_seg(env, R_ES, __USER_DS);
 222     cpu_x86_load_seg(env, R_SS, __USER_DS);
 223     cpu_x86_load_seg(env, R_FS, __USER_DS);
 224     cpu_x86_load_seg(env, R_GS, __USER_DS);
 225
 226     cpu_loop(env);
 227     /* never exits */
 228     return 0;
 229 }