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 /* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
  37    we allocate a bigger stack. Need a better solution, for example
  38    by remapping the process stack directly at the right place */
  39 unsigned long x86_stack_size = 512 * 1024;
  40 unsigned long stktop;
  41
  42 void gemu_log(const char *fmt, ...)
  43 {
  44     va_list ap;
  45
  46     va_start(ap, fmt);
  47     vfprintf(stderr, fmt, ap);
  48     va_end(ap);
  49 }
  50
  51 /***********************************************************/
  52 /* CPUX86 core interface */
  53
  54 void cpu_x86_outb(int addr, int val)
  55 {
  56     fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);
  57 }
  58
  59 void cpu_x86_outw(int addr, int val)
  60 {
  61     fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);
  62 }
  63
  64 void cpu_x86_outl(int addr, int val)
  65 {
  66     fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
  67 }
  68
  69 int cpu_x86_inb(int addr)
  70 {
  71     fprintf(stderr, "inb: port=0x%04x\n", addr);
  72     return 0;
  73 }
  74
  75 int cpu_x86_inw(int addr)
  76 {
  77     fprintf(stderr, "inw: port=0x%04x\n", addr);
  78     return 0;
  79 }
  80
  81 int cpu_x86_inl(int addr)
  82 {
  83     fprintf(stderr, "inl: port=0x%04x\n", addr);
  84     return 0;
  85 }
  86
  87 void write_dt(void *ptr, unsigned long addr, unsigned long limit,
  88               int seg32_bit)
  89 {
  90     unsigned int e1, e2, limit_in_pages;
  91     limit_in_pages = 0;
  92     if (limit > 0xffff) {
  93         limit = limit >> 12;
  94         limit_in_pages = 1;
  95     }
  96     e1 = (addr << 16) | (limit & 0xffff);
  97     e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);
  98     e2 |= limit_in_pages << 23; /* byte granularity */
  99     e2 |= seg32_bit << 22; /* 32 bit segment */
 100     stl((uint8_t *)ptr, e1);
 101     stl((uint8_t *)ptr + 4, e2);
 102 }
 103
 104 uint64_t gdt_table[6];
 105
 106 void cpu_loop(struct CPUX86State *env)
 107 {
 108     int err;
 109     uint8_t *pc;
 110     target_siginfo_t info;
 111
 112     for(;;) {
 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                 /* XXX: more precise info */
 130                 info.si_signo = SIGSEGV;
 131                 info.si_errno = 0;
 132                 info.si_code = 0;
 133                 info._sifields._sigfault._addr = 0;
 134                 queue_signal(info.si_signo, &info);
 135             }
 136             break;
 137         case EXCP00_DIVZ:
 138             /* division by zero */
 139             info.si_signo = SIGFPE;
 140             info.si_errno = 0;
 141             info.si_code = TARGET_FPE_INTDIV;
 142             info._sifields._sigfault._addr = env->eip;
 143             queue_signal(info.si_signo, &info);
 144             break;
 145         case EXCP04_INTO:
 146         case EXCP05_BOUND:
 147             info.si_signo = SIGSEGV;
 148             info.si_errno = 0;
 149             info.si_code = 0;
 150             info._sifields._sigfault._addr = 0;
 151             queue_signal(info.si_signo, &info);
 152             break;
 153         case EXCP06_ILLOP:
 154             info.si_signo = SIGILL;
 155             info.si_errno = 0;
 156             info.si_code = TARGET_ILL_ILLOPN;
 157             info._sifields._sigfault._addr = env->eip;
 158             queue_signal(info.si_signo, &info);
 159             break;
 160         case EXCP_INTERRUPT:
 161             /* just indicate that signals should be handled asap */
 162             break;
 163         default:
 164             fprintf(stderr, "0x%08lx: Unknown exception CPU %d, aborting\n",
 165                     (long)pc, err);
 166             abort();
 167         }
 168         process_pending_signals(env);
 169     }
 170 }
 171
 172 void usage(void)
 173 {
 174     printf("gemu version " GEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"
 175            "usage: gemu [-d] program [arguments...]\n"
 176            "Linux x86 emulator\n"
 177            );
 178     exit(1);
 179 }
 180
 181 /* XXX: currently only used for async signals (see signal.c) */
 182 CPUX86State *global_env;
 183
 184 int main(int argc, char **argv)
 185 {
 186     const char *filename;
 187     struct target_pt_regs regs1, *regs = &regs1;
 188     struct image_info info1, *info = &info1;
 189     CPUX86State *env;
 190     int optind;
 191
 192     if (argc <= 1)
 193         usage();
 194     loglevel = 0;
 195     optind = 1;
 196     if (argv[optind] && !strcmp(argv[optind], "-d")) {
 197         loglevel = 1;
 198         optind++;
 199     }
 200     filename = argv[optind];
 201
 202     /* init debug */
 203     if (loglevel) {
 204         logfile = fopen(DEBUG_LOGFILE, "w");
 205         if (!logfile) {
 206             perror(DEBUG_LOGFILE);
 207             exit(1);
 208         }
 209         setvbuf(logfile, NULL, _IOLBF, 0);
 210     }
 211
 212     /* Zero out regs */
 213     memset(regs, 0, sizeof(struct target_pt_regs));
 214
 215     /* Zero out image_info */
 216     memset(info, 0, sizeof(struct image_info));
 217
 218     if(elf_exec(filename, argv+optind, environ, regs, info) != 0) {
 219         printf("Error loading %s\n", filename);
 220         exit(1);
 221     }
 222
 223     if (loglevel) {
 224         fprintf(logfile, "start_brk   0x%08lx\n" , info->start_brk);
 225         fprintf(logfile, "end_code    0x%08lx\n" , info->end_code);
 226         fprintf(logfile, "start_code  0x%08lx\n" , info->start_code);
 227         fprintf(logfile, "end_data    0x%08lx\n" , info->end_data);
 228         fprintf(logfile, "start_stack 0x%08lx\n" , info->start_stack);
 229         fprintf(logfile, "brk         0x%08lx\n" , info->brk);
 230         fprintf(logfile, "esp         0x%08lx\n" , regs->esp);
 231         fprintf(logfile, "eip         0x%08lx\n" , regs->eip);
 232     }
 233
 234     target_set_brk((char *)info->brk);
 235     syscall_init();
 236     signal_init();
 237
 238     env = cpu_x86_init();
 239     global_env = env;
 240
 241     /* linux register setup */
 242     env->regs[R_EAX] = regs->eax;
 243     env->regs[R_EBX] = regs->ebx;
 244     env->regs[R_ECX] = regs->ecx;
 245     env->regs[R_EDX] = regs->edx;
 246     env->regs[R_ESI] = regs->esi;
 247     env->regs[R_EDI] = regs->edi;
 248     env->regs[R_EBP] = regs->ebp;
 249     env->regs[R_ESP] = regs->esp;
 250     env->eip = regs->eip;
 251
 252     /* linux segment setup */
 253     env->gdt.base = (void *)gdt_table;
 254     env->gdt.limit = sizeof(gdt_table) - 1;
 255     write_dt(&gdt_table[__USER_CS >> 3], 0, 0xffffffff, 1);
 256     write_dt(&gdt_table[__USER_DS >> 3], 0, 0xffffffff, 1);
 257     cpu_x86_load_seg(env, R_CS, __USER_CS);
 258     cpu_x86_load_seg(env, R_DS, __USER_DS);
 259     cpu_x86_load_seg(env, R_ES, __USER_DS);
 260     cpu_x86_load_seg(env, R_SS, __USER_DS);
 261     cpu_x86_load_seg(env, R_FS, __USER_DS);
 262     cpu_x86_load_seg(env, R_GS, __USER_DS);
 263
 264     cpu_loop(env);
 265     /* never exits */
 266     return 0;
 267 }