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 /* default linux values for the selectors */
  85 #define __USER_CS       (0x23)
  86 #define __USER_DS       (0x2B)
  87
  88 void write_dt(void *ptr, unsigned long addr, unsigned long limit,
  89               int seg32_bit)
  90 {
  91     unsigned int e1, e2, limit_in_pages;
  92     limit_in_pages = 0;
  93     if (limit > 0xffff) {
  94         limit = limit >> 12;
  95         limit_in_pages = 1;
  96     }
  97     e1 = (addr << 16) | (limit & 0xffff);
  98     e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);
  99     e2 |= limit_in_pages << 23; /* byte granularity */
 100     e2 |= seg32_bit << 22; /* 32 bit segment */
 101     stl((uint8_t *)ptr, e1);
 102     stl((uint8_t *)ptr + 4, e2);
 103 }
 104
 105 uint64_t gdt_table[6];
 106
 107 void cpu_loop(struct CPUX86State *env)
 108 {
 109     for(;;) {
 110         int err;
 111         uint8_t *pc;
 112
 113         err = cpu_x86_exec(env);
 114         pc = env->seg_cache[R_CS].base + env->eip;
 115         switch(err) {
 116         case EXCP0D_GPF:
 117             if (pc[0] == 0xcd && pc[1] == 0x80) {
 118                 /* syscall */
 119                 env->eip += 2;
 120                 env->regs[R_EAX] = do_syscall(env,
 121                                               env->regs[R_EAX],
 122                                               env->regs[R_EBX],
 123                                               env->regs[R_ECX],
 124                                               env->regs[R_EDX],
 125                                               env->regs[R_ESI],
 126                                               env->regs[R_EDI],
 127                                               env->regs[R_EBP]);
 128             } else {
 129                 goto trap_error;
 130             }
 131             break;
 132         default:
 133         trap_error:
 134             fprintf(stderr, "0x%08lx: Unknown exception %d, aborting\n",
 135                     (long)pc, err);
 136             abort();
 137         }
 138     }
 139 }
 140
 141 void usage(void)
 142 {
 143     printf("gemu version " GEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"
 144            "usage: gemu [-d] program [arguments...]\n"
 145            "Linux x86 emulator\n"
 146            );
 147     exit(1);
 148 }
 149
 150 int main(int argc, char **argv)
 151 {
 152     const char *filename;
 153     struct target_pt_regs regs1, *regs = &regs1;
 154     struct image_info info1, *info = &info1;
 155     CPUX86State *env;
 156     int optind;
 157
 158     if (argc <= 1)
 159         usage();
 160     loglevel = 0;
 161     optind = 1;
 162     if (argv[optind] && !strcmp(argv[optind], "-d")) {
 163         loglevel = 1;
 164         optind++;
 165     }
 166     filename = argv[optind];
 167
 168     /* init debug */
 169     if (loglevel) {
 170         logfile = fopen(DEBUG_LOGFILE, "w");
 171         if (!logfile) {
 172             perror(DEBUG_LOGFILE);
 173             exit(1);
 174         }
 175         setvbuf(logfile, NULL, _IOLBF, 0);
 176     }
 177
 178     /* Zero out regs */
 179     memset(regs, 0, sizeof(struct target_pt_regs));
 180
 181     /* Zero out image_info */
 182     memset(info, 0, sizeof(struct image_info));
 183
 184     if(elf_exec(filename, argv+optind, environ, regs, info) != 0) {
 185         printf("Error loading %s\n", filename);
 186         exit(1);
 187     }
 188
 189     if (loglevel) {
 190         fprintf(logfile, "start_brk   0x%08lx\n" , info->start_brk);
 191         fprintf(logfile, "end_code    0x%08lx\n" , info->end_code);
 192         fprintf(logfile, "start_code  0x%08lx\n" , info->start_code);
 193         fprintf(logfile, "end_data    0x%08lx\n" , info->end_data);
 194         fprintf(logfile, "start_stack 0x%08lx\n" , info->start_stack);
 195         fprintf(logfile, "brk         0x%08lx\n" , info->brk);
 196         fprintf(logfile, "esp         0x%08lx\n" , regs->esp);
 197         fprintf(logfile, "eip         0x%08lx\n" , regs->eip);
 198     }
 199
 200     target_set_brk((char *)info->brk);
 201     syscall_init();
 202
 203     env = cpu_x86_init();
 204
 205     /* linux register setup */
 206     env->regs[R_EAX] = regs->eax;
 207     env->regs[R_EBX] = regs->ebx;
 208     env->regs[R_ECX] = regs->ecx;
 209     env->regs[R_EDX] = regs->edx;
 210     env->regs[R_ESI] = regs->esi;
 211     env->regs[R_EDI] = regs->edi;
 212     env->regs[R_EBP] = regs->ebp;
 213     env->regs[R_ESP] = regs->esp;
 214     env->eip = regs->eip;
 215
 216     /* linux segment setup */
 217     env->gdt.base = (void *)gdt_table;
 218     env->gdt.limit = sizeof(gdt_table) - 1;
 219     write_dt(&gdt_table[__USER_CS >> 3], 0, 0xffffffff, 1);
 220     write_dt(&gdt_table[__USER_DS >> 3], 0, 0xffffffff, 1);
 221     cpu_x86_load_seg(env, R_CS, __USER_CS);
 222     cpu_x86_load_seg(env, R_DS, __USER_DS);
 223     cpu_x86_load_seg(env, R_ES, __USER_DS);
 224     cpu_x86_load_seg(env, R_SS, __USER_DS);
 225     cpu_x86_load_seg(env, R_FS, __USER_DS);
 226     cpu_x86_load_seg(env, R_GS, __USER_DS);
 227
 228     cpu_loop(env);
 229     /* never exits */
 230     return 0;
 231 }