linux-user/main.c

   1 /*
   2  *  qemu 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 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)
  27 #include <sys/personality.h>
  28 #endif
  29
  30 #include "qemu.h"
  31
  32 #include "cpu-i386.h"
  33
  34 #define DEBUG_LOGFILE "/tmp/qemu.log"
  35
  36 FILE *logfile = NULL;
  37 int loglevel;
  38 const char *interp_prefix = CONFIG_QEMU_PREFIX "/qemu-i386";
  39
  40 #ifdef __i386__
  41 /* Force usage of an ELF interpreter even if it is an ELF shared
  42    object ! */
  43 const char interp[] __attribute__((section(".interp"))) = "/lib/ld-linux.so.2";
  44 #endif
  45
  46 /* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
  47    we allocate a bigger stack. Need a better solution, for example
  48    by remapping the process stack directly at the right place */
  49 unsigned long x86_stack_size = 512 * 1024;
  50
  51 void gemu_log(const char *fmt, ...)
  52 {
  53     va_list ap;
  54
  55     va_start(ap, fmt);
  56     vfprintf(stderr, fmt, ap);
  57     va_end(ap);
  58 }
  59
  60 /***********************************************************/
  61 /* CPUX86 core interface */
  62
  63 void cpu_x86_outb(int addr, int val)
  64 {
  65     fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);
  66 }
  67
  68 void cpu_x86_outw(int addr, int val)
  69 {
  70     fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);
  71 }
  72
  73 void cpu_x86_outl(int addr, int val)
  74 {
  75     fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
  76 }
  77
  78 int cpu_x86_inb(int addr)
  79 {
  80     fprintf(stderr, "inb: port=0x%04x\n", addr);
  81     return 0;
  82 }
  83
  84 int cpu_x86_inw(int addr)
  85 {
  86     fprintf(stderr, "inw: port=0x%04x\n", addr);
  87     return 0;
  88 }
  89
  90 int cpu_x86_inl(int addr)
  91 {
  92     fprintf(stderr, "inl: port=0x%04x\n", addr);
  93     return 0;
  94 }
  95
  96 void write_dt(void *ptr, unsigned long addr, unsigned long limit,
  97               int seg32_bit)
  98 {
  99     unsigned int e1, e2, limit_in_pages;
 100     limit_in_pages = 0;
 101     if (limit > 0xffff) {
 102         limit = limit >> 12;
 103         limit_in_pages = 1;
 104     }
 105     e1 = (addr << 16) | (limit & 0xffff);
 106     e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);
 107     e2 |= limit_in_pages << 23; /* byte granularity */
 108     e2 |= seg32_bit << 22; /* 32 bit segment */
 109     stl((uint8_t *)ptr, e1);
 110     stl((uint8_t *)ptr + 4, e2);
 111 }
 112
 113 uint64_t gdt_table[6];
 114
 115 //#define DEBUG_VM86
 116
 117 static inline int is_revectored(int nr, struct target_revectored_struct *bitmap)
 118 {
 119     return (tswap32(bitmap->__map[nr >> 5]) >> (nr & 0x1f)) & 1;
 120 }
 121
 122 static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
 123 {
 124     return (uint8_t *)((seg << 4) + (reg & 0xffff));
 125 }
 126
 127 static inline void pushw(CPUX86State *env, int val)
 128 {
 129     env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) |
 130         ((env->regs[R_ESP] - 2) & 0xffff);
 131     *(uint16_t *)seg_to_linear(env->segs[R_SS], env->regs[R_ESP]) = val;
 132 }
 133
 134 static inline unsigned int get_vflags(CPUX86State *env)
 135 {
 136     unsigned int eflags;
 137     eflags = env->eflags & ~(VM_MASK | RF_MASK | IF_MASK);
 138     if (eflags & VIF_MASK)
 139         eflags |= IF_MASK;
 140     return eflags;
 141 }
 142
 143 void save_v86_state(CPUX86State *env)
 144 {
 145     TaskState *ts = env->opaque;
 146 #ifdef DEBUG_VM86
 147     printf("save_v86_state\n");
 148 #endif
 149
 150     /* put the VM86 registers in the userspace register structure */
 151     ts->target_v86->regs.eax = tswap32(env->regs[R_EAX]);
 152     ts->target_v86->regs.ebx = tswap32(env->regs[R_EBX]);
 153     ts->target_v86->regs.ecx = tswap32(env->regs[R_ECX]);
 154     ts->target_v86->regs.edx = tswap32(env->regs[R_EDX]);
 155     ts->target_v86->regs.esi = tswap32(env->regs[R_ESI]);
 156     ts->target_v86->regs.edi = tswap32(env->regs[R_EDI]);
 157     ts->target_v86->regs.ebp = tswap32(env->regs[R_EBP]);
 158     ts->target_v86->regs.esp = tswap32(env->regs[R_ESP]);
 159     ts->target_v86->regs.eip = tswap32(env->eip);
 160     ts->target_v86->regs.cs = tswap16(env->segs[R_CS]);
 161     ts->target_v86->regs.ss = tswap16(env->segs[R_SS]);
 162     ts->target_v86->regs.ds = tswap16(env->segs[R_DS]);
 163     ts->target_v86->regs.es = tswap16(env->segs[R_ES]);
 164     ts->target_v86->regs.fs = tswap16(env->segs[R_FS]);
 165     ts->target_v86->regs.gs = tswap16(env->segs[R_GS]);
 166     ts->target_v86->regs.eflags = tswap32(env->eflags);
 167
 168     /* restore 32 bit registers */
 169     env->regs[R_EAX] = ts->vm86_saved_regs.eax;
 170     env->regs[R_EBX] = ts->vm86_saved_regs.ebx;
 171     env->regs[R_ECX] = ts->vm86_saved_regs.ecx;
 172     env->regs[R_EDX] = ts->vm86_saved_regs.edx;
 173     env->regs[R_ESI] = ts->vm86_saved_regs.esi;
 174     env->regs[R_EDI] = ts->vm86_saved_regs.edi;
 175     env->regs[R_EBP] = ts->vm86_saved_regs.ebp;
 176     env->regs[R_ESP] = ts->vm86_saved_regs.esp;
 177     env->eflags = ts->vm86_saved_regs.eflags;
 178     env->eip = ts->vm86_saved_regs.eip;
 179
 180     cpu_x86_load_seg(env, R_CS, ts->vm86_saved_regs.cs);
 181     cpu_x86_load_seg(env, R_SS, ts->vm86_saved_regs.ss);
 182     cpu_x86_load_seg(env, R_DS, ts->vm86_saved_regs.ds);
 183     cpu_x86_load_seg(env, R_ES, ts->vm86_saved_regs.es);
 184     cpu_x86_load_seg(env, R_FS, ts->vm86_saved_regs.fs);
 185     cpu_x86_load_seg(env, R_GS, ts->vm86_saved_regs.gs);
 186 }
 187
 188 /* return from vm86 mode to 32 bit. The vm86() syscall will return
 189    'retval' */
 190 static inline void return_to_32bit(CPUX86State *env, int retval)
 191 {
 192 #ifdef DEBUG_VM86
 193     printf("return_to_32bit: ret=0x%x\n", retval);
 194 #endif
 195     save_v86_state(env);
 196     env->regs[R_EAX] = retval;
 197 }
 198
 199 /* handle VM86 interrupt (NOTE: the CPU core currently does not
 200    support TSS interrupt revectoring, so this code is always executed) */
 201 static void do_int(CPUX86State *env, int intno)
 202 {
 203     TaskState *ts = env->opaque;
 204     uint32_t *int_ptr, segoffs;
 205
 206     if (env->segs[R_CS] == TARGET_BIOSSEG)
 207         goto cannot_handle; /* XXX: I am not sure this is really useful */
 208     if (is_revectored(intno, &ts->target_v86->int_revectored))
 209         goto cannot_handle;
 210     if (intno == 0x21 && is_revectored((env->regs[R_EAX] >> 8) & 0xff,
 211                                        &ts->target_v86->int21_revectored))
 212         goto cannot_handle;
 213     int_ptr = (uint32_t *)(intno << 2);
 214     segoffs = tswap32(*int_ptr);
 215     if ((segoffs >> 16) == TARGET_BIOSSEG)
 216         goto cannot_handle;
 217 #ifdef DEBUG_VM86
 218     printf("VM86: emulating int 0x%x. CS:IP=%04x:%04x\n",
 219            intno, segoffs >> 16, segoffs & 0xffff);
 220 #endif
 221     /* save old state */
 222     pushw(env, get_vflags(env));
 223     pushw(env, env->segs[R_CS]);
 224     pushw(env, env->eip);
 225     /* goto interrupt handler */
 226     env->eip = segoffs & 0xffff;
 227     cpu_x86_load_seg(env, R_CS, segoffs >> 16);
 228     env->eflags &= ~(VIF_MASK | TF_MASK);
 229     return;
 230  cannot_handle:
 231 #ifdef DEBUG_VM86
 232     printf("VM86: return to 32 bits int 0x%x\n", intno);
 233 #endif
 234     return_to_32bit(env, TARGET_VM86_INTx | (intno << 8));
 235 }
 236
 237 void cpu_loop(struct CPUX86State *env)
 238 {
 239     int trapnr;
 240     uint8_t *pc;
 241     target_siginfo_t info;
 242
 243     for(;;) {
 244         trapnr = cpu_x86_exec(env);
 245         pc = env->seg_cache[R_CS].base + env->eip;
 246         switch(trapnr) {
 247         case EXCP0D_GPF:
 248             if (env->eflags & VM_MASK) {
 249 #ifdef DEBUG_VM86
 250                 printf("VM86 exception %04x:%08x %02x %02x\n",
 251                        env->segs[R_CS], env->eip, pc[0], pc[1]);
 252 #endif
 253                 /* VM86 mode */
 254                 switch(pc[0]) {
 255                 case 0xcd: /* int */
 256                     env->eip += 2;
 257                     do_int(env, pc[1]);
 258                     break;
 259                 case 0x66:
 260                     switch(pc[1]) {
 261                     case 0xfb: /* sti */
 262                     case 0x9d: /* popf */
 263                     case 0xcf: /* iret */
 264                         env->eip += 2;
 265                         return_to_32bit(env, TARGET_VM86_STI);
 266                         break;
 267                     default:
 268                         goto vm86_gpf;
 269                     }
 270                     break;
 271                 case 0xfb: /* sti */
 272                 case 0x9d: /* popf */
 273                 case 0xcf: /* iret */
 274                     env->eip++;
 275                     return_to_32bit(env, TARGET_VM86_STI);
 276                     break;
 277                 default:
 278                 vm86_gpf:
 279                     /* real VM86 GPF exception */
 280                     return_to_32bit(env, TARGET_VM86_UNKNOWN);
 281                     break;
 282                 }
 283             } else {
 284                 if (pc[0] == 0xcd && pc[1] == 0x80) {
 285                     /* syscall */
 286                     env->eip += 2;
 287                     env->regs[R_EAX] = do_syscall(env,
 288                                                   env->regs[R_EAX],
 289                                                   env->regs[R_EBX],
 290                                                   env->regs[R_ECX],
 291                                                   env->regs[R_EDX],
 292                                                   env->regs[R_ESI],
 293                                                   env->regs[R_EDI],
 294                                                   env->regs[R_EBP]);
 295                 } else {
 296                     /* XXX: more precise info */
 297                     info.si_signo = SIGSEGV;
 298                     info.si_errno = 0;
 299                     info.si_code = 0;
 300                     info._sifields._sigfault._addr = 0;
 301                     queue_signal(info.si_signo, &info);
 302                 }
 303             }
 304             break;
 305         case EXCP00_DIVZ:
 306             if (env->eflags & VM_MASK) {
 307                 do_int(env, trapnr);
 308             } else {
 309                 /* division by zero */
 310                 info.si_signo = SIGFPE;
 311                 info.si_errno = 0;
 312                 info.si_code = TARGET_FPE_INTDIV;
 313                 info._sifields._sigfault._addr = env->eip;
 314                 queue_signal(info.si_signo, &info);
 315             }
 316             break;
 317         case EXCP04_INTO:
 318         case EXCP05_BOUND:
 319             if (env->eflags & VM_MASK) {
 320                 do_int(env, trapnr);
 321             } else {
 322                 info.si_signo = SIGSEGV;
 323                 info.si_errno = 0;
 324                 info.si_code = 0;
 325                 info._sifields._sigfault._addr = 0;
 326                 queue_signal(info.si_signo, &info);
 327             }
 328             break;
 329         case EXCP06_ILLOP:
 330             info.si_signo = SIGILL;
 331             info.si_errno = 0;
 332             info.si_code = TARGET_ILL_ILLOPN;
 333             info._sifields._sigfault._addr = env->eip;
 334             queue_signal(info.si_signo, &info);
 335             break;
 336         case EXCP_INTERRUPT:
 337             /* just indicate that signals should be handled asap */
 338             break;
 339         default:
 340             fprintf(stderr, "qemu: 0x%08lx: unhandled CPU exception 0x%x - aborting\n",
 341                     (long)pc, trapnr);
 342             abort();
 343         }
 344         process_pending_signals(env);
 345     }
 346 }
 347
 348 void usage(void)
 349 {
 350     printf("qemu version " QEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"
 351            "usage: qemu [-h] [-d] [-L path] [-s size] program [arguments...]\n"
 352            "Linux x86 emulator\n"
 353            "\n"
 354            "-h        print this help\n"
 355            "-d        activate log (logfile=%s)\n"
 356            "-L path   set the x86 elf interpreter prefix (default=%s)\n"
 357            "-s size   set the x86 stack size in bytes (default=%ld)\n",
 358            DEBUG_LOGFILE,
 359            interp_prefix,
 360            x86_stack_size);
 361     exit(1);
 362 }
 363
 364 /* XXX: currently only used for async signals (see signal.c) */
 365 CPUX86State *global_env;
 366 /* used to free thread contexts */
 367 TaskState *first_task_state;
 368
 369 int main(int argc, char **argv)
 370 {
 371     const char *filename;
 372     struct target_pt_regs regs1, *regs = &regs1;
 373     struct image_info info1, *info = &info1;
 374     TaskState ts1, *ts = &ts1;
 375     CPUX86State *env;
 376     int optind;
 377     const char *r;
 378
 379     if (argc <= 1)
 380         usage();
 381
 382     /* Set personality to X86_LINUX.  May fail on unpatched kernels:
 383        if so, they need to have munged paths themselves (eg. chroot,
 384        hacked ld.so, whatever). */
 385     if (personality(0x11) >= 0)
 386             interp_prefix = "";
 387
 388     loglevel = 0;
 389     optind = 1;
 390     for(;;) {
 391         if (optind >= argc)
 392             break;
 393         r = argv[optind];
 394         if (r[0] != '-')
 395             break;
 396         optind++;
 397         r++;
 398         if (!strcmp(r, "-")) {
 399             break;
 400         } else if (!strcmp(r, "d")) {
 401             loglevel = 1;
 402         } else if (!strcmp(r, "s")) {
 403             r = argv[optind++];
 404             x86_stack_size = strtol(r, (char **)&r, 0);
 405             if (x86_stack_size <= 0)
 406                 usage();
 407             if (*r == 'M')
 408                 x86_stack_size *= 1024 * 1024;
 409             else if (*r == 'k' || *r == 'K')
 410                 x86_stack_size *= 1024;
 411         } else if (!strcmp(r, "L")) {
 412             interp_prefix = argv[optind++];
 413         } else {
 414             usage();
 415         }
 416     }
 417     if (optind >= argc)
 418         usage();
 419     filename = argv[optind];
 420
 421     /* init debug */
 422     if (loglevel) {
 423         logfile = fopen(DEBUG_LOGFILE, "w");
 424         if (!logfile) {
 425             perror(DEBUG_LOGFILE);
 426             exit(1);
 427         }
 428         setvbuf(logfile, NULL, _IOLBF, 0);
 429     }
 430
 431     /* Zero out regs */
 432     memset(regs, 0, sizeof(struct target_pt_regs));
 433
 434     /* Zero out image_info */
 435     memset(info, 0, sizeof(struct image_info));
 436
 437     if(elf_exec(interp_prefix, filename, argv+optind, environ, regs, info) != 0) {
 438         printf("Error loading %s\n", filename);
 439         exit(1);
 440     }
 441
 442     if (loglevel) {
 443         fprintf(logfile, "start_brk   0x%08lx\n" , info->start_brk);
 444         fprintf(logfile, "end_code    0x%08lx\n" , info->end_code);
 445         fprintf(logfile, "start_code  0x%08lx\n" , info->start_code);
 446         fprintf(logfile, "end_data    0x%08lx\n" , info->end_data);
 447         fprintf(logfile, "start_stack 0x%08lx\n" , info->start_stack);
 448         fprintf(logfile, "brk         0x%08lx\n" , info->brk);
 449         fprintf(logfile, "esp         0x%08lx\n" , regs->esp);
 450         fprintf(logfile, "eip         0x%08lx\n" , regs->eip);
 451     }
 452
 453     target_set_brk((char *)info->brk);
 454     syscall_init();
 455     signal_init();
 456
 457     env = cpu_x86_init();
 458     global_env = env;
 459
 460     /* build Task State */
 461     memset(ts, 0, sizeof(TaskState));
 462     env->opaque = ts;
 463     ts->used = 1;
 464
 465     /* linux register setup */
 466     env->regs[R_EAX] = regs->eax;
 467     env->regs[R_EBX] = regs->ebx;
 468     env->regs[R_ECX] = regs->ecx;
 469     env->regs[R_EDX] = regs->edx;
 470     env->regs[R_ESI] = regs->esi;
 471     env->regs[R_EDI] = regs->edi;
 472     env->regs[R_EBP] = regs->ebp;
 473     env->regs[R_ESP] = regs->esp;
 474     env->eip = regs->eip;
 475
 476     /* linux segment setup */
 477     env->gdt.base = (void *)gdt_table;
 478     env->gdt.limit = sizeof(gdt_table) - 1;
 479     write_dt(&gdt_table[__USER_CS >> 3], 0, 0xffffffff, 1);
 480     write_dt(&gdt_table[__USER_DS >> 3], 0, 0xffffffff, 1);
 481     cpu_x86_load_seg(env, R_CS, __USER_CS);
 482     cpu_x86_load_seg(env, R_DS, __USER_DS);
 483     cpu_x86_load_seg(env, R_ES, __USER_DS);
 484     cpu_x86_load_seg(env, R_SS, __USER_DS);
 485     cpu_x86_load_seg(env, R_FS, __USER_DS);
 486     cpu_x86_load_seg(env, R_GS, __USER_DS);
 487
 488     cpu_loop(env);
 489     /* never exits */
 490     return 0;
 491 }