arch/sparc64/kernel/ptrace.c

   1 /* ptrace.c: Sparc process tracing support.
   2  *
   3  * Copyright (C) 1996 David S. Miller (davem@caipfs.rutgers.edu)
   4  * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   5  *
   6  * Based upon code written by Ross Biro, Linus Torvalds, Bob Manson,
   7  * and David Mosberger.
   8  *
   9  * Added Linux support -miguel (weird, eh?, the original code was meant
  10  * to emulate SunOS).
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/errno.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/user.h>
  19 #include <linux/smp.h>
  20 #include <linux/smp_lock.h>
  21 #include <linux/security.h>
  22
  23 #include <asm/asi.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/system.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/psrcompat.h>
  28 #include <asm/visasm.h>
  29 #include <asm/spitfire.h>
  30
  31 /* Returning from ptrace is a bit tricky because the syscall return
  32  * low level code assumes any value returned which is negative and
  33  * is a valid errno will mean setting the condition codes to indicate
  34  * an error return.  This doesn't work, so we have this hook.
  35  */
  36 static inline void pt_error_return(struct pt_regs *regs, unsigned long error)
  37 {
  38         regs->u_regs[UREG_I0] = error;
  39         regs->tstate |= (TSTATE_ICARRY | TSTATE_XCARRY);
  40         regs->tpc = regs->tnpc;
  41         regs->tnpc += 4;
  42 }
  43
  44 static inline void pt_succ_return(struct pt_regs *regs, unsigned long value)
  45 {
  46         regs->u_regs[UREG_I0] = value;
  47         regs->tstate &= ~(TSTATE_ICARRY | TSTATE_XCARRY);
  48         regs->tpc = regs->tnpc;
  49         regs->tnpc += 4;
  50 }
  51
  52 static inline void
  53 pt_succ_return_linux(struct pt_regs *regs, unsigned long value, long *addr)
  54 {
  55         if (test_thread_flag(TIF_32BIT)) {
  56                 if (put_user(value, (unsigned int *)addr))
  57                         return pt_error_return(regs, EFAULT);
  58         } else {
  59                 if (put_user(value, addr))
  60                         return pt_error_return(regs, EFAULT);
  61         }
  62         regs->u_regs[UREG_I0] = 0;
  63         regs->tstate &= ~(TSTATE_ICARRY | TSTATE_XCARRY);
  64         regs->tpc = regs->tnpc;
  65         regs->tnpc += 4;
  66 }
  67
  68 static void
  69 pt_os_succ_return (struct pt_regs *regs, unsigned long val, long *addr)
  70 {
  71         if (current->personality == PER_SUNOS)
  72                 pt_succ_return (regs, val);
  73         else
  74                 pt_succ_return_linux (regs, val, addr);
  75 }
  76
  77 /* #define ALLOW_INIT_TRACING */
  78 /* #define DEBUG_PTRACE */
  79
  80 #ifdef DEBUG_PTRACE
  81 char *pt_rq [] = {
  82         /* 0  */ "TRACEME", "PEEKTEXT", "PEEKDATA", "PEEKUSR",
  83         /* 4  */ "POKETEXT", "POKEDATA", "POKEUSR", "CONT",
  84         /* 8  */ "KILL", "SINGLESTEP", "SUNATTACH", "SUNDETACH",
  85         /* 12 */ "GETREGS", "SETREGS", "GETFPREGS", "SETFPREGS",
  86         /* 16 */ "READDATA", "WRITEDATA", "READTEXT", "WRITETEXT",
  87         /* 20 */ "GETFPAREGS", "SETFPAREGS", "unknown", "unknown",
  88         /* 24 */ "SYSCALL", ""
  89 };
  90 #endif
  91
  92 /*
  93  * Called by kernel/ptrace.c when detaching..
  94  *
  95  * Make sure single step bits etc are not set.
  96  */
  97 void ptrace_disable(struct task_struct *child)
  98 {
  99         /* nothing to do */
 100 }
 101
 102 asmlinkage void do_ptrace(struct pt_regs *regs)
 103 {
 104         int request = regs->u_regs[UREG_I0];
 105         pid_t pid = regs->u_regs[UREG_I1];
 106         unsigned long addr = regs->u_regs[UREG_I2];
 107         unsigned long data = regs->u_regs[UREG_I3];
 108         unsigned long addr2 = regs->u_regs[UREG_I4];
 109         struct task_struct *child;
 110         int ret;
 111
 112         if (test_thread_flag(TIF_32BIT)) {
 113                 addr &= 0xffffffffUL;
 114                 data &= 0xffffffffUL;
 115                 addr2 &= 0xffffffffUL;
 116         }
 117         lock_kernel();
 118 #ifdef DEBUG_PTRACE
 119         {
 120                 char *s;
 121
 122                 if ((request >= 0) && (request <= 24))
 123                         s = pt_rq [request];
 124                 else
 125                         s = "unknown";
 126
 127                 if (request == PTRACE_POKEDATA && data == 0x91d02001){
 128                         printk ("do_ptrace: breakpoint pid=%d, addr=%016lx addr2=%016lx\n",
 129                                 pid, addr, addr2);
 130                 } else
 131                         printk("do_ptrace: rq=%s(%d) pid=%d addr=%016lx data=%016lx addr2=%016lx\n",
 132                                s, request, pid, addr, data, addr2);
 133         }
 134 #endif
 135         if (request == PTRACE_TRACEME) {
 136                 int ret;
 137
 138                 /* are we already being traced? */
 139                 if (current->ptrace & PT_PTRACED) {
 140                         pt_error_return(regs, EPERM);
 141                         goto out;
 142                 }
 143                 ret = security_ptrace(current->parent, current);
 144                 if (ret) {
 145                         pt_error_return(regs, -ret);
 146                         goto out;
 147                 }
 148
 149                 /* set the ptrace bit in the process flags. */
 150                 current->ptrace |= PT_PTRACED;
 151                 pt_succ_return(regs, 0);
 152                 goto out;
 153         }
 154 #ifndef ALLOW_INIT_TRACING
 155         if (pid == 1) {
 156                 /* Can't dork with init. */
 157                 pt_error_return(regs, EPERM);
 158                 goto out;
 159         }
 160 #endif
 161         read_lock(&tasklist_lock);
 162         child = find_task_by_pid(pid);
 163         if (child)
 164                 get_task_struct(child);
 165         read_unlock(&tasklist_lock);
 166
 167         if (!child) {
 168                 pt_error_return(regs, ESRCH);
 169                 goto out;
 170         }
 171
 172         if ((current->personality == PER_SUNOS && request == PTRACE_SUNATTACH)
 173             || (current->personality != PER_SUNOS && request == PTRACE_ATTACH)) {
 174                 if (ptrace_attach(child)) {
 175                         pt_error_return(regs, EPERM);
 176                         goto out_tsk;
 177                 }
 178                 pt_succ_return(regs, 0);
 179                 goto out_tsk;
 180         }
 181
 182         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 183         if (ret < 0) {
 184                 pt_error_return(regs, -ret);
 185                 goto out_tsk;
 186         }
 187
 188         if (!(test_thread_flag(TIF_32BIT))      &&
 189             ((request == PTRACE_READDATA64)             ||
 190              (request == PTRACE_WRITEDATA64)            ||
 191              (request == PTRACE_READTEXT64)             ||
 192              (request == PTRACE_WRITETEXT64)            ||
 193              (request == PTRACE_PEEKTEXT64)             ||
 194              (request == PTRACE_POKETEXT64)             ||
 195              (request == PTRACE_PEEKDATA64)             ||
 196              (request == PTRACE_POKEDATA64))) {
 197                 addr = regs->u_regs[UREG_G2];
 198                 addr2 = regs->u_regs[UREG_G3];
 199                 request -= 30; /* wheee... */
 200         }
 201
 202         switch(request) {
 203         case PTRACE_PEEKTEXT: /* read word at location addr. */
 204         case PTRACE_PEEKDATA: {
 205                 unsigned long tmp64;
 206                 unsigned int tmp32;
 207                 int res, copied;
 208
 209                 res = -EIO;
 210                 if (test_thread_flag(TIF_32BIT)) {
 211                         copied = access_process_vm(child, addr,
 212                                                    &tmp32, sizeof(tmp32), 0);
 213                         tmp64 = (unsigned long) tmp32;
 214                         if (copied == sizeof(tmp32))
 215                                 res = 0;
 216                 } else {
 217                         copied = access_process_vm(child, addr,
 218                                                    &tmp64, sizeof(tmp64), 0);
 219                         if (copied == sizeof(tmp64))
 220                                 res = 0;
 221                 }
 222                 if (res < 0)
 223                         pt_error_return(regs, -res);
 224                 else
 225                         pt_os_succ_return(regs, tmp64, (long *) data);
 226                 goto flush_and_out;
 227         }
 228
 229         case PTRACE_POKETEXT: /* write the word at location addr. */
 230         case PTRACE_POKEDATA: {
 231                 unsigned long tmp64;
 232                 unsigned int tmp32;
 233                 int copied, res = -EIO;
 234
 235                 if (test_thread_flag(TIF_32BIT)) {
 236                         tmp32 = data;
 237                         copied = access_process_vm(child, addr,
 238                                                    &tmp32, sizeof(tmp32), 1);
 239                         if (copied == sizeof(tmp32))
 240                                 res = 0;
 241                 } else {
 242                         tmp64 = data;
 243                         copied = access_process_vm(child, addr,
 244                                                    &tmp64, sizeof(tmp64), 1);
 245                         if (copied == sizeof(tmp64))
 246                                 res = 0;
 247                 }
 248                 if (res < 0)
 249                         pt_error_return(regs, -res);
 250                 else
 251                         pt_succ_return(regs, res);
 252                 goto flush_and_out;
 253         }
 254
 255         case PTRACE_GETREGS: {
 256                 struct pt_regs32 *pregs = (struct pt_regs32 *) addr;
 257                 struct pt_regs *cregs = child->thread_info->kregs;
 258                 int rval;
 259
 260                 if (__put_user(tstate_to_psr(cregs->tstate), (&pregs->psr)) ||
 261                     __put_user(cregs->tpc, (&pregs->pc)) ||
 262                     __put_user(cregs->tnpc, (&pregs->npc)) ||
 263                     __put_user(cregs->y, (&pregs->y))) {
 264                         pt_error_return(regs, EFAULT);
 265                         goto out_tsk;
 266                 }
 267                 for (rval = 1; rval < 16; rval++)
 268                         if (__put_user(cregs->u_regs[rval], (&pregs->u_regs[rval - 1]))) {
 269                                 pt_error_return(regs, EFAULT);
 270                                 goto out_tsk;
 271                         }
 272                 pt_succ_return(regs, 0);
 273 #ifdef DEBUG_PTRACE
 274                 printk ("PC=%lx nPC=%lx o7=%lx\n", cregs->tpc, cregs->tnpc, cregs->u_regs [15]);
 275 #endif
 276                 goto out_tsk;
 277         }
 278
 279         case PTRACE_GETREGS64: {
 280                 struct pt_regs *pregs = (struct pt_regs *) addr;
 281                 struct pt_regs *cregs = child->thread_info->kregs;
 282                 unsigned long tpc = cregs->tpc;
 283                 int rval;
 284
 285                 if ((child->thread_info->flags & _TIF_32BIT) != 0)
 286                         tpc &= 0xffffffff;
 287                 if (__put_user(cregs->tstate, (&pregs->tstate)) ||
 288                     __put_user(tpc, (&pregs->tpc)) ||
 289                     __put_user(cregs->tnpc, (&pregs->tnpc)) ||
 290                     __put_user(cregs->y, (&pregs->y))) {
 291                         pt_error_return(regs, EFAULT);
 292                         goto out_tsk;
 293                 }
 294                 for (rval = 1; rval < 16; rval++)
 295                         if (__put_user(cregs->u_regs[rval], (&pregs->u_regs[rval - 1]))) {
 296                                 pt_error_return(regs, EFAULT);
 297                                 goto out_tsk;
 298                         }
 299                 pt_succ_return(regs, 0);
 300 #ifdef DEBUG_PTRACE
 301                 printk ("PC=%lx nPC=%lx o7=%lx\n", cregs->tpc, cregs->tnpc, cregs->u_regs [15]);
 302 #endif
 303                 goto out_tsk;
 304         }
 305
 306         case PTRACE_SETREGS: {
 307                 struct pt_regs32 *pregs = (struct pt_regs32 *) addr;
 308                 struct pt_regs *cregs = child->thread_info->kregs;
 309                 unsigned int psr, pc, npc, y;
 310                 int i;
 311
 312                 /* Must be careful, tracing process can only set certain
 313                  * bits in the psr.
 314                  */
 315                 if (__get_user(psr, (&pregs->psr)) ||
 316                     __get_user(pc, (&pregs->pc)) ||
 317                     __get_user(npc, (&pregs->npc)) ||
 318                     __get_user(y, (&pregs->y))) {
 319                         pt_error_return(regs, EFAULT);
 320                         goto out_tsk;
 321                 }
 322                 cregs->tstate &= ~(TSTATE_ICC);
 323                 cregs->tstate |= psr_to_tstate_icc(psr);
 324                 if (!((pc | npc) & 3)) {
 325                         cregs->tpc = pc;
 326                         cregs->tnpc = npc;
 327                 }
 328                 cregs->y = y;
 329                 for (i = 1; i < 16; i++) {
 330                         if (__get_user(cregs->u_regs[i], (&pregs->u_regs[i-1]))) {
 331                                 pt_error_return(regs, EFAULT);
 332                                 goto out_tsk;
 333                         }
 334                 }
 335                 pt_succ_return(regs, 0);
 336                 goto out_tsk;
 337         }
 338
 339         case PTRACE_SETREGS64: {
 340                 struct pt_regs *pregs = (struct pt_regs *) addr;
 341                 struct pt_regs *cregs = child->thread_info->kregs;
 342                 unsigned long tstate, tpc, tnpc, y;
 343                 int i;
 344
 345                 /* Must be careful, tracing process can only set certain
 346                  * bits in the psr.
 347                  */
 348                 if (__get_user(tstate, (&pregs->tstate)) ||
 349                     __get_user(tpc, (&pregs->tpc)) ||
 350                     __get_user(tnpc, (&pregs->tnpc)) ||
 351                     __get_user(y, (&pregs->y))) {
 352                         pt_error_return(regs, EFAULT);
 353                         goto out_tsk;
 354                 }
 355                 if ((child->thread_info->flags & _TIF_32BIT) != 0) {
 356                         tpc &= 0xffffffff;
 357                         tnpc &= 0xffffffff;
 358                 }
 359                 tstate &= (TSTATE_ICC | TSTATE_XCC);
 360                 cregs->tstate &= ~(TSTATE_ICC | TSTATE_XCC);
 361                 cregs->tstate |= tstate;
 362                 if (!((tpc | tnpc) & 3)) {
 363                         cregs->tpc = tpc;
 364                         cregs->tnpc = tnpc;
 365                 }
 366                 cregs->y = y;
 367                 for (i = 1; i < 16; i++) {
 368                         if (__get_user(cregs->u_regs[i], (&pregs->u_regs[i-1]))) {
 369                                 pt_error_return(regs, EFAULT);
 370                                 goto out_tsk;
 371                         }
 372                 }
 373                 pt_succ_return(regs, 0);
 374                 goto out_tsk;
 375         }
 376
 377         case PTRACE_GETFPREGS: {
 378                 struct fps {
 379                         unsigned int regs[32];
 380                         unsigned int fsr;
 381                         unsigned int flags;
 382                         unsigned int extra;
 383                         unsigned int fpqd;
 384                         struct fq {
 385                                 unsigned int insnaddr;
 386                                 unsigned int insn;
 387                         } fpq[16];
 388                 } *fps = (struct fps *) addr;
 389                 unsigned long *fpregs = child->thread_info->fpregs;
 390
 391                 if (copy_to_user(&fps->regs[0], fpregs,
 392                                  (32 * sizeof(unsigned int))) ||
 393                     __put_user(child->thread_info->xfsr[0], (&fps->fsr)) ||
 394                     __put_user(0, (&fps->fpqd)) ||
 395                     __put_user(0, (&fps->flags)) ||
 396                     __put_user(0, (&fps->extra)) ||
 397                     clear_user(&fps->fpq[0], 32 * sizeof(unsigned int))) {
 398                         pt_error_return(regs, EFAULT);
 399                         goto out_tsk;
 400                 }
 401                 pt_succ_return(regs, 0);
 402                 goto out_tsk;
 403         }
 404
 405         case PTRACE_GETFPREGS64: {
 406                 struct fps {
 407                         unsigned int regs[64];
 408                         unsigned long fsr;
 409                 } *fps = (struct fps *) addr;
 410                 unsigned long *fpregs = child->thread_info->fpregs;
 411
 412                 if (copy_to_user(&fps->regs[0], fpregs,
 413                                  (64 * sizeof(unsigned int))) ||
 414                     __put_user(child->thread_info->xfsr[0], (&fps->fsr))) {
 415                         pt_error_return(regs, EFAULT);
 416                         goto out_tsk;
 417                 }
 418                 pt_succ_return(regs, 0);
 419                 goto out_tsk;
 420         }
 421
 422         case PTRACE_SETFPREGS: {
 423                 struct fps {
 424                         unsigned int regs[32];
 425                         unsigned int fsr;
 426                         unsigned int flags;
 427                         unsigned int extra;
 428                         unsigned int fpqd;
 429                         struct fq {
 430                                 unsigned int insnaddr;
 431                                 unsigned int insn;
 432                         } fpq[16];
 433                 } *fps = (struct fps *) addr;
 434                 unsigned long *fpregs = child->thread_info->fpregs;
 435                 unsigned fsr;
 436
 437                 if (copy_from_user(fpregs, &fps->regs[0],
 438                                    (32 * sizeof(unsigned int))) ||
 439                     __get_user(fsr, (&fps->fsr))) {
 440                         pt_error_return(regs, EFAULT);
 441                         goto out_tsk;
 442                 }
 443                 child->thread_info->xfsr[0] &= 0xffffffff00000000UL;
 444                 child->thread_info->xfsr[0] |= fsr;
 445                 if (!(child->thread_info->fpsaved[0] & FPRS_FEF))
 446                         child->thread_info->gsr[0] = 0;
 447                 child->thread_info->fpsaved[0] |= (FPRS_FEF | FPRS_DL);
 448                 pt_succ_return(regs, 0);
 449                 goto out_tsk;
 450         }
 451
 452         case PTRACE_SETFPREGS64: {
 453                 struct fps {
 454                         unsigned int regs[64];
 455                         unsigned long fsr;
 456                 } *fps = (struct fps *) addr;
 457                 unsigned long *fpregs = child->thread_info->fpregs;
 458
 459                 if (copy_from_user(fpregs, &fps->regs[0],
 460                                    (64 * sizeof(unsigned int))) ||
 461                     __get_user(child->thread_info->xfsr[0], (&fps->fsr))) {
 462                         pt_error_return(regs, EFAULT);
 463                         goto out_tsk;
 464                 }
 465                 if (!(child->thread_info->fpsaved[0] & FPRS_FEF))
 466                         child->thread_info->gsr[0] = 0;
 467                 child->thread_info->fpsaved[0] |= (FPRS_FEF | FPRS_DL | FPRS_DU);
 468                 pt_succ_return(regs, 0);
 469                 goto out_tsk;
 470         }
 471
 472         case PTRACE_READTEXT:
 473         case PTRACE_READDATA: {
 474                 int res = ptrace_readdata(child, addr,
 475                                           (void *)addr2, data);
 476                 if (res == data) {
 477                         pt_succ_return(regs, 0);
 478                         goto flush_and_out;
 479                 }
 480                 if (res >= 0)
 481                         res = -EIO;
 482                 pt_error_return(regs, -res);
 483                 goto flush_and_out;
 484         }
 485
 486         case PTRACE_WRITETEXT:
 487         case PTRACE_WRITEDATA: {
 488                 int res = ptrace_writedata(child, (void *) addr2,
 489                                            addr, data);
 490                 if (res == data) {
 491                         pt_succ_return(regs, 0);
 492                         goto flush_and_out;
 493                 }
 494                 if (res >= 0)
 495                         res = -EIO;
 496                 pt_error_return(regs, -res);
 497                 goto flush_and_out;
 498         }
 499         case PTRACE_SYSCALL: /* continue and stop at (return from) syscall */
 500                 addr = 1;
 501
 502         case PTRACE_CONT: { /* restart after signal. */
 503                 if (data > _NSIG) {
 504                         pt_error_return(regs, EIO);
 505                         goto out_tsk;
 506                 }
 507                 if (addr != 1) {
 508                         unsigned long pc_mask = ~0UL;
 509
 510                         if ((child->thread_info->flags & _TIF_32BIT) != 0)
 511                                 pc_mask = 0xffffffff;
 512
 513                         if (addr & 3) {
 514                                 pt_error_return(regs, EINVAL);
 515                                 goto out_tsk;
 516                         }
 517 #ifdef DEBUG_PTRACE
 518                         printk ("Original: %016lx %016lx\n",
 519                                 child->thread_info->kregs->tpc,
 520                                 child->thread_info->kregs->tnpc);
 521                         printk ("Continuing with %016lx %016lx\n", addr, addr+4);
 522 #endif
 523                         child->thread_info->kregs->tpc = (addr & pc_mask);
 524                         child->thread_info->kregs->tnpc = ((addr + 4) & pc_mask);
 525                 }
 526
 527                 if (request == PTRACE_SYSCALL) {
 528                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 529                 } else {
 530                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 531                 }
 532
 533                 child->exit_code = data;
 534 #ifdef DEBUG_PTRACE
 535                 printk("CONT: %s [%d]: set exit_code = %x %lx %lx\n", child->comm,
 536                         child->pid, child->exit_code,
 537                         child->thread_info->kregs->tpc,
 538                         child->thread_info->kregs->tnpc);
 539
 540 #endif
 541                 wake_up_process(child);
 542                 pt_succ_return(regs, 0);
 543                 goto out_tsk;
 544         }
 545
 546 /*
 547  * make the child exit.  Best I can do is send it a sigkill.
 548  * perhaps it should be put in the status that it wants to
 549  * exit.
 550  */
 551         case PTRACE_KILL: {
 552                 if (child->state == TASK_ZOMBIE) {      /* already dead */
 553                         pt_succ_return(regs, 0);
 554                         goto out_tsk;
 555                 }
 556                 child->exit_code = SIGKILL;
 557                 wake_up_process(child);
 558                 pt_succ_return(regs, 0);
 559                 goto out_tsk;
 560         }
 561
 562         case PTRACE_SUNDETACH: { /* detach a process that was attached. */
 563                 int error = ptrace_detach(child, data);
 564                 if (error) {
 565                         pt_error_return(regs, EIO);
 566                         goto out_tsk;
 567                 }
 568                 pt_succ_return(regs, 0);
 569                 goto out_tsk;
 570         }
 571
 572         /* PTRACE_DUMPCORE unsupported... */
 573
 574         default: {
 575                 int err = ptrace_request(child, request, addr, data);
 576                 if (err)
 577                         pt_error_return(regs, -err);
 578                 else
 579                         pt_succ_return(regs, 0);
 580                 goto out_tsk;
 581         }
 582         }
 583 flush_and_out:
 584         {
 585                 unsigned long va;
 586
 587                 if (tlb_type == cheetah || tlb_type == cheetah_plus) {
 588                         for (va = 0; va < (1 << 16); va += (1 << 5))
 589                                 spitfire_put_dcache_tag(va, 0x0);
 590                         /* No need to mess with I-cache on Cheetah. */
 591                 } else {
 592                         for (va =  0; va < L1DCACHE_SIZE; va += 32)
 593                                 spitfire_put_dcache_tag(va, 0x0);
 594                         if (request == PTRACE_PEEKTEXT ||
 595                             request == PTRACE_POKETEXT ||
 596                             request == PTRACE_READTEXT ||
 597                             request == PTRACE_WRITETEXT) {
 598                                 for (va =  0; va < (PAGE_SIZE << 1); va += 32)
 599                                         spitfire_put_icache_tag(va, 0x0);
 600                                 __asm__ __volatile__("flush %g6");
 601                         }
 602                 }
 603         }
 604 out_tsk:
 605         if (child)
 606                 put_task_struct(child);
 607 out:
 608         unlock_kernel();
 609 }
 610
 611 asmlinkage void syscall_trace(void)
 612 {
 613 #ifdef DEBUG_PTRACE
 614         printk("%s [%d]: syscall_trace\n", current->comm, current->pid);
 615 #endif
 616         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 617                 return;
 618         if (!(current->ptrace & PT_PTRACED))
 619                 return;
 620         current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 621                                         ? 0x80 : 0);
 622         current->state = TASK_STOPPED;
 623         notify_parent(current, SIGCHLD);
 624         schedule();
 625
 626         /*
 627          * this isn't the same as continuing with a signal, but it will do
 628          * for normal use.  strace only continues with a signal if the
 629          * stopping signal is not SIGTRAP.  -brl
 630          */
 631 #ifdef DEBUG_PTRACE
 632         printk("%s [%d]: syscall_trace exit= %x\n", current->comm,
 633                 current->pid, current->exit_code);
 634 #endif
 635         if (current->exit_code) {
 636                 send_sig (current->exit_code, current, 1);
 637                 current->exit_code = 0;
 638         }
 639 }