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
  27 #include "qemu.h"
  28
  29 #include "cpu-i386.h"
  30
  31 #define DEBUG_LOGFILE "/tmp/qemu.log"
  32
  33 FILE *logfile = NULL;
  34 int loglevel;
  35 static const char *interp_prefix = CONFIG_QEMU_PREFIX;
  36
  37 #ifdef __i386__
  38 /* Force usage of an ELF interpreter even if it is an ELF shared
  39    object ! */
  40 const char interp[] __attribute__((section(".interp"))) = "/lib/ld-linux.so.2";
  41
  42 /* for recent libc, we add these dummies symbol which are not declared
  43    when generating a linked object (bug in ld ?) */
  44 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)
  45 long __init_array_start[0];
  46 long __init_array_end[0];
  47 long __fini_array_start[0];
  48 long __fini_array_end[0];
  49 #endif
  50
  51 #endif
  52
  53 /* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
  54    we allocate a bigger stack. Need a better solution, for example
  55    by remapping the process stack directly at the right place */
  56 unsigned long x86_stack_size = 512 * 1024;
  57
  58 void gemu_log(const char *fmt, ...)
  59 {
  60     va_list ap;
  61
  62     va_start(ap, fmt);
  63     vfprintf(stderr, fmt, ap);
  64     va_end(ap);
  65 }
  66
  67 /***********************************************************/
  68 /* CPUX86 core interface */
  69
  70 void cpu_x86_outb(CPUX86State *env, int addr, int val)
  71 {
  72     fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);
  73 }
  74
  75 void cpu_x86_outw(CPUX86State *env, int addr, int val)
  76 {
  77     fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);
  78 }
  79
  80 void cpu_x86_outl(CPUX86State *env, int addr, int val)
  81 {
  82     fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
  83 }
  84
  85 int cpu_x86_inb(CPUX86State *env, int addr)
  86 {
  87     fprintf(stderr, "inb: port=0x%04x\n", addr);
  88     return 0;
  89 }
  90
  91 int cpu_x86_inw(CPUX86State *env, int addr)
  92 {
  93     fprintf(stderr, "inw: port=0x%04x\n", addr);
  94     return 0;
  95 }
  96
  97 int cpu_x86_inl(CPUX86State *env, int addr)
  98 {
  99     fprintf(stderr, "inl: port=0x%04x\n", addr);
 100     return 0;
 101 }
 102
 103 void write_dt(void *ptr, unsigned long addr, unsigned long limit,
 104               int seg32_bit)
 105 {
 106     unsigned int e1, e2, limit_in_pages;
 107     limit_in_pages = 0;
 108     if (limit > 0xffff) {
 109         limit = limit >> 12;
 110         limit_in_pages = 1;
 111     }
 112     e1 = (addr << 16) | (limit & 0xffff);
 113     e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);
 114     e2 |= limit_in_pages << 23; /* byte granularity */
 115     e2 |= seg32_bit << 22; /* 32 bit segment */
 116     stl((uint8_t *)ptr, e1);
 117     stl((uint8_t *)ptr + 4, e2);
 118 }
 119
 120 uint64_t gdt_table[6];
 121
 122 //#define DEBUG_VM86
 123
 124 static inline int is_revectored(int nr, struct target_revectored_struct *bitmap)
 125 {
 126     return (tswap32(bitmap->__map[nr >> 5]) >> (nr & 0x1f)) & 1;
 127 }
 128
 129 static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
 130 {
 131     return (uint8_t *)((seg << 4) + (reg & 0xffff));
 132 }
 133
 134 static inline void pushw(CPUX86State *env, int val)
 135 {
 136     env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) |
 137         ((env->regs[R_ESP] - 2) & 0xffff);
 138     *(uint16_t *)seg_to_linear(env->segs[R_SS], env->regs[R_ESP]) = val;
 139 }
 140
 141 static inline unsigned int get_vflags(CPUX86State *env)
 142 {
 143     unsigned int eflags;
 144     eflags = env->eflags & ~(VM_MASK | RF_MASK | IF_MASK);
 145     if (eflags & VIF_MASK)
 146         eflags |= IF_MASK;
 147     return eflags;
 148 }
 149
 150 void save_v86_state(CPUX86State *env)
 151 {
 152     TaskState *ts = env->opaque;
 153 #ifdef DEBUG_VM86
 154     printf("save_v86_state\n");
 155 #endif
 156
 157     /* put the VM86 registers in the userspace register structure */
 158     ts->target_v86->regs.eax = tswap32(env->regs[R_EAX]);
 159     ts->target_v86->regs.ebx = tswap32(env->regs[R_EBX]);
 160     ts->target_v86->regs.ecx = tswap32(env->regs[R_ECX]);
 161     ts->target_v86->regs.edx = tswap32(env->regs[R_EDX]);
 162     ts->target_v86->regs.esi = tswap32(env->regs[R_ESI]);
 163     ts->target_v86->regs.edi = tswap32(env->regs[R_EDI]);
 164     ts->target_v86->regs.ebp = tswap32(env->regs[R_EBP]);
 165     ts->target_v86->regs.esp = tswap32(env->regs[R_ESP]);
 166     ts->target_v86->regs.eip = tswap32(env->eip);
 167     ts->target_v86->regs.cs = tswap16(env->segs[R_CS]);
 168     ts->target_v86->regs.ss = tswap16(env->segs[R_SS]);
 169     ts->target_v86->regs.ds = tswap16(env->segs[R_DS]);
 170     ts->target_v86->regs.es = tswap16(env->segs[R_ES]);
 171     ts->target_v86->regs.fs = tswap16(env->segs[R_FS]);
 172     ts->target_v86->regs.gs = tswap16(env->segs[R_GS]);
 173     ts->target_v86->regs.eflags = tswap32(env->eflags);
 174
 175     /* restore 32 bit registers */
 176     env->regs[R_EAX] = ts->vm86_saved_regs.eax;
 177     env->regs[R_EBX] = ts->vm86_saved_regs.ebx;
 178     env->regs[R_ECX] = ts->vm86_saved_regs.ecx;
 179     env->regs[R_EDX] = ts->vm86_saved_regs.edx;
 180     env->regs[R_ESI] = ts->vm86_saved_regs.esi;
 181     env->regs[R_EDI] = ts->vm86_saved_regs.edi;
 182     env->regs[R_EBP] = ts->vm86_saved_regs.ebp;
 183     env->regs[R_ESP] = ts->vm86_saved_regs.esp;
 184     env->eflags = ts->vm86_saved_regs.eflags;
 185     env->eip = ts->vm86_saved_regs.eip;
 186
 187     cpu_x86_load_seg(env, R_CS, ts->vm86_saved_regs.cs);
 188     cpu_x86_load_seg(env, R_SS, ts->vm86_saved_regs.ss);
 189     cpu_x86_load_seg(env, R_DS, ts->vm86_saved_regs.ds);
 190     cpu_x86_load_seg(env, R_ES, ts->vm86_saved_regs.es);
 191     cpu_x86_load_seg(env, R_FS, ts->vm86_saved_regs.fs);
 192     cpu_x86_load_seg(env, R_GS, ts->vm86_saved_regs.gs);
 193 }
 194
 195 /* return from vm86 mode to 32 bit. The vm86() syscall will return
 196    'retval' */
 197 static inline void return_to_32bit(CPUX86State *env, int retval)
 198 {
 199 #ifdef DEBUG_VM86
 200     printf("return_to_32bit: ret=0x%x\n", retval);
 201 #endif
 202     save_v86_state(env);
 203     env->regs[R_EAX] = retval;
 204 }
 205
 206 /* handle VM86 interrupt (NOTE: the CPU core currently does not
 207    support TSS interrupt revectoring, so this code is always executed) */
 208 static void do_int(CPUX86State *env, int intno)
 209 {
 210     TaskState *ts = env->opaque;
 211     uint32_t *int_ptr, segoffs;
 212
 213     if (env->segs[R_CS] == TARGET_BIOSSEG)
 214         goto cannot_handle; /* XXX: I am not sure this is really useful */
 215     if (is_revectored(intno, &ts->target_v86->int_revectored))
 216         goto cannot_handle;
 217     if (intno == 0x21 && is_revectored((env->regs[R_EAX] >> 8) & 0xff,
 218                                        &ts->target_v86->int21_revectored))
 219         goto cannot_handle;
 220     int_ptr = (uint32_t *)(intno << 2);
 221     segoffs = tswap32(*int_ptr);
 222     if ((segoffs >> 16) == TARGET_BIOSSEG)
 223         goto cannot_handle;
 224 #ifdef DEBUG_VM86
 225     printf("VM86: emulating int 0x%x. CS:IP=%04x:%04x\n",
 226            intno, segoffs >> 16, segoffs & 0xffff);
 227 #endif
 228     /* save old state */
 229     pushw(env, get_vflags(env));
 230     pushw(env, env->segs[R_CS]);
 231     pushw(env, env->eip);
 232     /* goto interrupt handler */
 233     env->eip = segoffs & 0xffff;
 234     cpu_x86_load_seg(env, R_CS, segoffs >> 16);
 235     env->eflags &= ~(VIF_MASK | TF_MASK);
 236     return;
 237  cannot_handle:
 238 #ifdef DEBUG_VM86
 239     printf("VM86: return to 32 bits int 0x%x\n", intno);
 240 #endif
 241     return_to_32bit(env, TARGET_VM86_INTx | (intno << 8));
 242 }
 243
 244 void cpu_loop(struct CPUX86State *env)
 245 {
 246     int trapnr;
 247     uint8_t *pc;
 248     target_siginfo_t info;
 249
 250     for(;;) {
 251         trapnr = cpu_x86_exec(env);
 252         pc = env->seg_cache[R_CS].base + env->eip;
 253         switch(trapnr) {
 254         case EXCP0D_GPF:
 255             if (env->eflags & VM_MASK) {
 256 #ifdef DEBUG_VM86
 257                 printf("VM86 exception %04x:%08x %02x %02x\n",
 258                        env->segs[R_CS], env->eip, pc[0], pc[1]);
 259 #endif
 260                 /* VM86 mode */
 261                 switch(pc[0]) {
 262                 case 0xcd: /* int */
 263                     env->eip += 2;
 264                     do_int(env, pc[1]);
 265                     break;
 266                 case 0x66:
 267                     switch(pc[1]) {
 268                     case 0xfb: /* sti */
 269                     case 0x9d: /* popf */
 270                     case 0xcf: /* iret */
 271                         env->eip += 2;
 272                         return_to_32bit(env, TARGET_VM86_STI);
 273                         break;
 274                     default:
 275                         goto vm86_gpf;
 276                     }
 277                     break;
 278                 case 0xfb: /* sti */
 279                 case 0x9d: /* popf */
 280                 case 0xcf: /* iret */
 281                     env->eip++;
 282                     return_to_32bit(env, TARGET_VM86_STI);
 283                     break;
 284                 default:
 285                 vm86_gpf:
 286                     /* real VM86 GPF exception */
 287                     return_to_32bit(env, TARGET_VM86_UNKNOWN);
 288                     break;
 289                 }
 290             } else {
 291                 if (pc[0] == 0xcd && pc[1] == 0x80) {
 292                     /* syscall */
 293                     env->eip += 2;
 294                     env->regs[R_EAX] = do_syscall(env,
 295                                                   env->regs[R_EAX],
 296                                                   env->regs[R_EBX],
 297                                                   env->regs[R_ECX],
 298                                                   env->regs[R_EDX],
 299                                                   env->regs[R_ESI],
 300                                                   env->regs[R_EDI],
 301                                                   env->regs[R_EBP]);
 302                 } else {
 303                     /* XXX: more precise info */
 304                     info.si_signo = SIGSEGV;
 305                     info.si_errno = 0;
 306                     info.si_code = TARGET_SI_KERNEL;
 307                     info._sifields._sigfault._addr = 0;
 308                     queue_signal(info.si_signo, &info);
 309                 }
 310             }
 311             break;
 312         case EXCP0E_PAGE:
 313             info.si_signo = SIGSEGV;
 314             info.si_errno = 0;
 315             if (!(env->error_code & 1))
 316                 info.si_code = TARGET_SEGV_MAPERR;
 317             else
 318                 info.si_code = TARGET_SEGV_ACCERR;
 319             info._sifields._sigfault._addr = env->cr2;
 320             queue_signal(info.si_signo, &info);
 321             break;
 322         case EXCP00_DIVZ:
 323             if (env->eflags & VM_MASK) {
 324                 do_int(env, trapnr);
 325             } else {
 326                 /* division by zero */
 327                 info.si_signo = SIGFPE;
 328                 info.si_errno = 0;
 329                 info.si_code = TARGET_FPE_INTDIV;
 330                 info._sifields._sigfault._addr = env->eip;
 331                 queue_signal(info.si_signo, &info);
 332             }
 333             break;
 334         case EXCP04_INTO:
 335         case EXCP05_BOUND:
 336             if (env->eflags & VM_MASK) {
 337                 do_int(env, trapnr);
 338             } else {
 339                 info.si_signo = SIGSEGV;
 340                 info.si_errno = 0;
 341                 info.si_code = TARGET_SI_KERNEL;
 342                 info._sifields._sigfault._addr = 0;
 343                 queue_signal(info.si_signo, &info);
 344             }
 345             break;
 346         case EXCP06_ILLOP:
 347             info.si_signo = SIGILL;
 348             info.si_errno = 0;
 349             info.si_code = TARGET_ILL_ILLOPN;
 350             info._sifields._sigfault._addr = env->eip;
 351             queue_signal(info.si_signo, &info);
 352             break;
 353         case EXCP_INTERRUPT:
 354             /* just indicate that signals should be handled asap */
 355             break;
 356         default:
 357             fprintf(stderr, "qemu: 0x%08lx: unhandled CPU exception 0x%x - aborting\n",
 358                     (long)pc, trapnr);
 359             abort();
 360         }
 361         process_pending_signals(env);
 362     }
 363 }
 364
 365 void usage(void)
 366 {
 367     printf("qemu version " QEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"
 368            "usage: qemu [-h] [-d] [-L path] [-s size] program [arguments...]\n"
 369            "Linux x86 emulator\n"
 370            "\n"
 371            "-h        print this help\n"
 372            "-d        activate log (logfile=%s)\n"
 373            "-L path   set the x86 elf interpreter prefix (default=%s)\n"
 374            "-s size   set the x86 stack size in bytes (default=%ld)\n",
 375            DEBUG_LOGFILE,
 376            interp_prefix,
 377            x86_stack_size);
 378     _exit(1);
 379 }
 380
 381 /* XXX: currently only used for async signals (see signal.c) */
 382 CPUX86State *global_env;
 383 /* used to free thread contexts */
 384 TaskState *first_task_state;
 385
 386 int main(int argc, char **argv)
 387 {
 388     const char *filename;
 389     struct target_pt_regs regs1, *regs = &regs1;
 390     struct image_info info1, *info = &info1;
 391     TaskState ts1, *ts = &ts1;
 392     CPUX86State *env;
 393     int optind;
 394     const char *r;
 395
 396     if (argc <= 1)
 397         usage();
 398
 399     loglevel = 0;
 400     optind = 1;
 401     for(;;) {
 402         if (optind >= argc)
 403             break;
 404         r = argv[optind];
 405         if (r[0] != '-')
 406             break;
 407         optind++;
 408         r++;
 409         if (!strcmp(r, "-")) {
 410             break;
 411         } else if (!strcmp(r, "d")) {
 412             loglevel = 1;
 413         } else if (!strcmp(r, "s")) {
 414             r = argv[optind++];
 415             x86_stack_size = strtol(r, (char **)&r, 0);
 416             if (x86_stack_size <= 0)
 417                 usage();
 418             if (*r == 'M')
 419                 x86_stack_size *= 1024 * 1024;
 420             else if (*r == 'k' || *r == 'K')
 421                 x86_stack_size *= 1024;
 422         } else if (!strcmp(r, "L")) {
 423             interp_prefix = argv[optind++];
 424         } else {
 425             usage();
 426         }
 427     }
 428     if (optind >= argc)
 429         usage();
 430     filename = argv[optind];
 431
 432     /* init debug */
 433     if (loglevel) {
 434         logfile = fopen(DEBUG_LOGFILE, "w");
 435         if (!logfile) {
 436             perror(DEBUG_LOGFILE);
 437             _exit(1);
 438         }
 439         setvbuf(logfile, NULL, _IOLBF, 0);
 440     }
 441
 442     /* Zero out regs */
 443     memset(regs, 0, sizeof(struct target_pt_regs));
 444
 445     /* Zero out image_info */
 446     memset(info, 0, sizeof(struct image_info));
 447
 448     /* Scan interp_prefix dir for replacement files. */
 449     init_paths(interp_prefix);
 450
 451     if (elf_exec(filename, argv+optind, environ, regs, info) != 0) {
 452         printf("Error loading %s\n", filename);
 453         _exit(1);
 454     }
 455
 456     if (loglevel) {
 457         fprintf(logfile, "start_brk   0x%08lx\n" , info->start_brk);
 458         fprintf(logfile, "end_code    0x%08lx\n" , info->end_code);
 459         fprintf(logfile, "start_code  0x%08lx\n" , info->start_code);
 460         fprintf(logfile, "end_data    0x%08lx\n" , info->end_data);
 461         fprintf(logfile, "start_stack 0x%08lx\n" , info->start_stack);
 462         fprintf(logfile, "brk         0x%08lx\n" , info->brk);
 463         fprintf(logfile, "esp         0x%08lx\n" , regs->esp);
 464         fprintf(logfile, "eip         0x%08lx\n" , regs->eip);
 465     }
 466
 467     target_set_brk((char *)info->brk);
 468     syscall_init();
 469     signal_init();
 470
 471     env = cpu_x86_init();
 472     global_env = env;
 473
 474     /* build Task State */
 475     memset(ts, 0, sizeof(TaskState));
 476     env->opaque = ts;
 477     ts->used = 1;
 478
 479     /* linux register setup */
 480     env->regs[R_EAX] = regs->eax;
 481     env->regs[R_EBX] = regs->ebx;
 482     env->regs[R_ECX] = regs->ecx;
 483     env->regs[R_EDX] = regs->edx;
 484     env->regs[R_ESI] = regs->esi;
 485     env->regs[R_EDI] = regs->edi;
 486     env->regs[R_EBP] = regs->ebp;
 487     env->regs[R_ESP] = regs->esp;
 488     env->eip = regs->eip;
 489
 490     /* linux segment setup */
 491     env->gdt.base = (void *)gdt_table;
 492     env->gdt.limit = sizeof(gdt_table) - 1;
 493     write_dt(&gdt_table[__USER_CS >> 3], 0, 0xffffffff, 1);
 494     write_dt(&gdt_table[__USER_DS >> 3], 0, 0xffffffff, 1);
 495     cpu_x86_load_seg(env, R_CS, __USER_CS);
 496     cpu_x86_load_seg(env, R_DS, __USER_DS);
 497     cpu_x86_load_seg(env, R_ES, __USER_DS);
 498     cpu_x86_load_seg(env, R_SS, __USER_DS);
 499     cpu_x86_load_seg(env, R_FS, __USER_DS);
 500     cpu_x86_load_seg(env, R_GS, __USER_DS);
 501
 502     cpu_loop(env);
 503     /* never exits */
 504     return 0;
 505 }