arch/x86/ia32/ia32_signal.c

   1 /*
   2  *  linux/arch/x86_64/ia32/ia32_signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   7  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
   8  *  2000-12-*   x86-64 compatibility mode signal handling by Andi Kleen
   9  */
  10
  11 #include <linux/sched.h>
  12 #include <linux/mm.h>
  13 #include <linux/smp.h>
  14 #include <linux/kernel.h>
  15 #include <linux/signal.h>
  16 #include <linux/errno.h>
  17 #include <linux/wait.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/unistd.h>
  20 #include <linux/stddef.h>
  21 #include <linux/personality.h>
  22 #include <linux/compat.h>
  23 #include <linux/binfmts.h>
  24 #include <asm/ucontext.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/i387.h>
  27 #include <asm/ia32.h>
  28 #include <asm/ptrace.h>
  29 #include <asm/ia32_unistd.h>
  30 #include <asm/user32.h>
  31 #include <asm/sigcontext32.h>
  32 #include <asm/proto.h>
  33 #include <asm/vdso.h>
  34
  35 #define DEBUG_SIG 0
  36
  37 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  38
  39 #define FIX_EFLAGS      (X86_EFLAGS_AC | X86_EFLAGS_OF | \
  40                          X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
  41                          X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
  42                          X86_EFLAGS_CF)
  43
  44 asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
  45 void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
  46
  47 int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
  48 {
  49         int err;
  50
  51         if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
  52                 return -EFAULT;
  53
  54         /* If you change siginfo_t structure, please make sure that
  55            this code is fixed accordingly.
  56            It should never copy any pad contained in the structure
  57            to avoid security leaks, but must copy the generic
  58            3 ints plus the relevant union member.  */
  59         err = __put_user(from->si_signo, &to->si_signo);
  60         err |= __put_user(from->si_errno, &to->si_errno);
  61         err |= __put_user((short)from->si_code, &to->si_code);
  62
  63         if (from->si_code < 0) {
  64                 err |= __put_user(from->si_pid, &to->si_pid);
  65                 err |= __put_user(from->si_uid, &to->si_uid);
  66                 err |= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
  67         } else {
  68                 /*
  69                  * First 32bits of unions are always present:
  70                  * si_pid === si_band === si_tid === si_addr(LS half)
  71                  */
  72                 err |= __put_user(from->_sifields._pad[0],
  73                                   &to->_sifields._pad[0]);
  74                 switch (from->si_code >> 16) {
  75                 case __SI_FAULT >> 16:
  76                         break;
  77                 case __SI_CHLD >> 16:
  78                         err |= __put_user(from->si_utime, &to->si_utime);
  79                         err |= __put_user(from->si_stime, &to->si_stime);
  80                         err |= __put_user(from->si_status, &to->si_status);
  81                         /* FALL THROUGH */
  82                 default:
  83                 case __SI_KILL >> 16:
  84                         err |= __put_user(from->si_uid, &to->si_uid);
  85                         break;
  86                 case __SI_POLL >> 16:
  87                         err |= __put_user(from->si_fd, &to->si_fd);
  88                         break;
  89                 case __SI_TIMER >> 16:
  90                         err |= __put_user(from->si_overrun, &to->si_overrun);
  91                         err |= __put_user(ptr_to_compat(from->si_ptr),
  92                                           &to->si_ptr);
  93                         break;
  94                          /* This is not generated by the kernel as of now.  */
  95                 case __SI_RT >> 16:
  96                 case __SI_MESGQ >> 16:
  97                         err |= __put_user(from->si_uid, &to->si_uid);
  98                         err |= __put_user(from->si_int, &to->si_int);
  99                         break;
 100                 }
 101         }
 102         return err;
 103 }
 104
 105 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
 106 {
 107         int err;
 108         u32 ptr32;
 109
 110         if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
 111                 return -EFAULT;
 112
 113         err = __get_user(to->si_signo, &from->si_signo);
 114         err |= __get_user(to->si_errno, &from->si_errno);
 115         err |= __get_user(to->si_code, &from->si_code);
 116
 117         err |= __get_user(to->si_pid, &from->si_pid);
 118         err |= __get_user(to->si_uid, &from->si_uid);
 119         err |= __get_user(ptr32, &from->si_ptr);
 120         to->si_ptr = compat_ptr(ptr32);
 121
 122         return err;
 123 }
 124
 125 asmlinkage long sys32_sigsuspend(int history0, int history1, old_sigset_t mask)
 126 {
 127         mask &= _BLOCKABLE;
 128         spin_lock_irq(&current->sighand->siglock);
 129         current->saved_sigmask = current->blocked;
 130         siginitset(&current->blocked, mask);
 131         recalc_sigpending();
 132         spin_unlock_irq(&current->sighand->siglock);
 133
 134         current->state = TASK_INTERRUPTIBLE;
 135         schedule();
 136         set_restore_sigmask();
 137         return -ERESTARTNOHAND;
 138 }
 139
 140 asmlinkage long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
 141                                   stack_ia32_t __user *uoss_ptr,
 142                                   struct pt_regs *regs)
 143 {
 144         stack_t uss, uoss;
 145         int ret;
 146         mm_segment_t seg;
 147
 148         if (uss_ptr) {
 149                 u32 ptr;
 150
 151                 memset(&uss, 0, sizeof(stack_t));
 152                 if (!access_ok(VERIFY_READ, uss_ptr, sizeof(stack_ia32_t)) ||
 153                             __get_user(ptr, &uss_ptr->ss_sp) ||
 154                             __get_user(uss.ss_flags, &uss_ptr->ss_flags) ||
 155                             __get_user(uss.ss_size, &uss_ptr->ss_size))
 156                         return -EFAULT;
 157                 uss.ss_sp = compat_ptr(ptr);
 158         }
 159         seg = get_fs();
 160         set_fs(KERNEL_DS);
 161         ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, regs->sp);
 162         set_fs(seg);
 163         if (ret >= 0 && uoss_ptr)  {
 164                 if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_ia32_t)) ||
 165                     __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
 166                     __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
 167                     __put_user(uoss.ss_size, &uoss_ptr->ss_size))
 168                         ret = -EFAULT;
 169         }
 170         return ret;
 171 }
 172
 173 /*
 174  * Do a signal return; undo the signal stack.
 175  */
 176
 177 struct sigframe
 178 {
 179         u32 pretcode;
 180         int sig;
 181         struct sigcontext_ia32 sc;
 182         struct _fpstate_ia32 fpstate_unused; /* look at kernel/sigframe.h */
 183         unsigned int extramask[_COMPAT_NSIG_WORDS-1];
 184         char retcode[8];
 185         /* fp state follows here */
 186 };
 187
 188 struct rt_sigframe
 189 {
 190         u32 pretcode;
 191         int sig;
 192         u32 pinfo;
 193         u32 puc;
 194         compat_siginfo_t info;
 195         struct ucontext_ia32 uc;
 196         char retcode[8];
 197         /* fp state follows here */
 198 };
 199
 200 #define COPY(x)         {               \
 201         unsigned int reg;               \
 202         err |= __get_user(reg, &sc->x); \
 203         regs->x = reg;                  \
 204 }
 205
 206 #define RELOAD_SEG(seg,mask)                                            \
 207         { unsigned int cur;                                             \
 208           unsigned short pre;                                           \
 209           err |= __get_user(pre, &sc->seg);                             \
 210           asm volatile("movl %%" #seg ",%0" : "=r" (cur));              \
 211           pre |= mask;                                                  \
 212           if (pre != cur) loadsegment(seg, pre); }
 213
 214 static int ia32_restore_sigcontext(struct pt_regs *regs,
 215                                    struct sigcontext_ia32 __user *sc,
 216                                    unsigned int *peax)
 217 {
 218         unsigned int tmpflags, gs, oldgs, err = 0;
 219         void __user *buf;
 220         u32 tmp;
 221
 222         /* Always make any pending restarted system calls return -EINTR */
 223         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 224
 225 #if DEBUG_SIG
 226         printk(KERN_DEBUG "SIG restore_sigcontext: "
 227                "sc=%p err(%x) eip(%x) cs(%x) flg(%x)\n",
 228                sc, sc->err, sc->ip, sc->cs, sc->flags);
 229 #endif
 230
 231         /*
 232          * Reload fs and gs if they have changed in the signal
 233          * handler.  This does not handle long fs/gs base changes in
 234          * the handler, but does not clobber them at least in the
 235          * normal case.
 236          */
 237         err |= __get_user(gs, &sc->gs);
 238         gs |= 3;
 239         asm("movl %%gs,%0" : "=r" (oldgs));
 240         if (gs != oldgs)
 241                 load_gs_index(gs);
 242
 243         RELOAD_SEG(fs, 3);
 244         RELOAD_SEG(ds, 3);
 245         RELOAD_SEG(es, 3);
 246
 247         COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
 248         COPY(dx); COPY(cx); COPY(ip);
 249         /* Don't touch extended registers */
 250
 251         err |= __get_user(regs->cs, &sc->cs);
 252         regs->cs |= 3;
 253         err |= __get_user(regs->ss, &sc->ss);
 254         regs->ss |= 3;
 255
 256         err |= __get_user(tmpflags, &sc->flags);
 257         regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 258         /* disable syscall checks */
 259         regs->orig_ax = -1;
 260
 261         err |= __get_user(tmp, &sc->fpstate);
 262         buf = compat_ptr(tmp);
 263         err |= restore_i387_xstate_ia32(buf);
 264
 265         err |= __get_user(tmp, &sc->ax);
 266         *peax = tmp;
 267
 268         return err;
 269 }
 270
 271 asmlinkage long sys32_sigreturn(struct pt_regs *regs)
 272 {
 273         struct sigframe __user *frame = (struct sigframe __user *)(regs->sp-8);
 274         sigset_t set;
 275         unsigned int ax;
 276
 277         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 278                 goto badframe;
 279         if (__get_user(set.sig[0], &frame->sc.oldmask)
 280             || (_COMPAT_NSIG_WORDS > 1
 281                 && __copy_from_user((((char *) &set.sig) + 4),
 282                                     &frame->extramask,
 283                                     sizeof(frame->extramask))))
 284                 goto badframe;
 285
 286         sigdelsetmask(&set, ~_BLOCKABLE);
 287         spin_lock_irq(&current->sighand->siglock);
 288         current->blocked = set;
 289         recalc_sigpending();
 290         spin_unlock_irq(&current->sighand->siglock);
 291
 292         if (ia32_restore_sigcontext(regs, &frame->sc, &ax))
 293                 goto badframe;
 294         return ax;
 295
 296 badframe:
 297         signal_fault(regs, frame, "32bit sigreturn");
 298         return 0;
 299 }
 300
 301 asmlinkage long sys32_rt_sigreturn(struct pt_regs *regs)
 302 {
 303         struct rt_sigframe __user *frame;
 304         sigset_t set;
 305         unsigned int ax;
 306         struct pt_regs tregs;
 307
 308         frame = (struct rt_sigframe __user *)(regs->sp - 4);
 309
 310         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 311                 goto badframe;
 312         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 313                 goto badframe;
 314
 315         sigdelsetmask(&set, ~_BLOCKABLE);
 316         spin_lock_irq(&current->sighand->siglock);
 317         current->blocked = set;
 318         recalc_sigpending();
 319         spin_unlock_irq(&current->sighand->siglock);
 320
 321         if (ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 322                 goto badframe;
 323
 324         tregs = *regs;
 325         if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
 326                 goto badframe;
 327
 328         return ax;
 329
 330 badframe:
 331         signal_fault(regs, frame, "32bit rt sigreturn");
 332         return 0;
 333 }
 334
 335 /*
 336  * Set up a signal frame.
 337  */
 338
 339 static int ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc,
 340                                  void __user *fpstate,
 341                                  struct pt_regs *regs, unsigned int mask)
 342 {
 343         int tmp, err = 0;
 344
 345         tmp = 0;
 346         __asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp));
 347         err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
 348         __asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp));
 349         err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
 350         __asm__("movl %%ds,%0" : "=r"(tmp): "0"(tmp));
 351         err |= __put_user(tmp, (unsigned int __user *)&sc->ds);
 352         __asm__("movl %%es,%0" : "=r"(tmp): "0"(tmp));
 353         err |= __put_user(tmp, (unsigned int __user *)&sc->es);
 354
 355         err |= __put_user((u32)regs->di, &sc->di);
 356         err |= __put_user((u32)regs->si, &sc->si);
 357         err |= __put_user((u32)regs->bp, &sc->bp);
 358         err |= __put_user((u32)regs->sp, &sc->sp);
 359         err |= __put_user((u32)regs->bx, &sc->bx);
 360         err |= __put_user((u32)regs->dx, &sc->dx);
 361         err |= __put_user((u32)regs->cx, &sc->cx);
 362         err |= __put_user((u32)regs->ax, &sc->ax);
 363         err |= __put_user((u32)regs->cs, &sc->cs);
 364         err |= __put_user((u32)regs->ss, &sc->ss);
 365         err |= __put_user(current->thread.trap_no, &sc->trapno);
 366         err |= __put_user(current->thread.error_code, &sc->err);
 367         err |= __put_user((u32)regs->ip, &sc->ip);
 368         err |= __put_user((u32)regs->flags, &sc->flags);
 369         err |= __put_user((u32)regs->sp, &sc->sp_at_signal);
 370
 371         tmp = save_i387_xstate_ia32(fpstate);
 372         if (tmp < 0)
 373                 err = -EFAULT;
 374         else {
 375                 clear_used_math();
 376                 stts();
 377                 err |= __put_user(ptr_to_compat(tmp ? fpstate : NULL),
 378                                         &sc->fpstate);
 379         }
 380
 381         /* non-iBCS2 extensions.. */
 382         err |= __put_user(mask, &sc->oldmask);
 383         err |= __put_user(current->thread.cr2, &sc->cr2);
 384
 385         return err;
 386 }
 387
 388 /*
 389  * Determine which stack to use..
 390  */
 391 static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 392                                  size_t frame_size,
 393                                  void **fpstate)
 394 {
 395         unsigned long sp;
 396
 397         /* Default to using normal stack */
 398         sp = regs->sp;
 399
 400         /* This is the X/Open sanctioned signal stack switching.  */
 401         if (ka->sa.sa_flags & SA_ONSTACK) {
 402                 if (sas_ss_flags(sp) == 0)
 403                         sp = current->sas_ss_sp + current->sas_ss_size;
 404         }
 405
 406         /* This is the legacy signal stack switching. */
 407         else if ((regs->ss & 0xffff) != __USER_DS &&
 408                 !(ka->sa.sa_flags & SA_RESTORER) &&
 409                  ka->sa.sa_restorer)
 410                 sp = (unsigned long) ka->sa.sa_restorer;
 411
 412         if (used_math()) {
 413                 sp = sp - sig_xstate_ia32_size;
 414                 *fpstate = (struct _fpstate_ia32 *) sp;
 415         }
 416
 417         sp -= frame_size;
 418         /* Align the stack pointer according to the i386 ABI,
 419          * i.e. so that on function entry ((sp + 4) & 15) == 0. */
 420         sp = ((sp + 4) & -16ul) - 4;
 421         return (void __user *) sp;
 422 }
 423
 424 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 425                      compat_sigset_t *set, struct pt_regs *regs)
 426 {
 427         struct sigframe __user *frame;
 428         void __user *restorer;
 429         int err = 0;
 430         void __user *fpstate = NULL;
 431
 432         /* copy_to_user optimizes that into a single 8 byte store */
 433         static const struct {
 434                 u16 poplmovl;
 435                 u32 val;
 436                 u16 int80;
 437                 u16 pad;
 438         } __attribute__((packed)) code = {
 439                 0xb858,          /* popl %eax ; movl $...,%eax */
 440                 __NR_ia32_sigreturn,
 441                 0x80cd,         /* int $0x80 */
 442                 0,
 443         };
 444
 445         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 446
 447         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 448                 goto give_sigsegv;
 449
 450         err |= __put_user(sig, &frame->sig);
 451         if (err)
 452                 goto give_sigsegv;
 453
 454         err |= ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]);
 455         if (err)
 456                 goto give_sigsegv;
 457
 458         if (_COMPAT_NSIG_WORDS > 1) {
 459                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 460                                       sizeof(frame->extramask));
 461                 if (err)
 462                         goto give_sigsegv;
 463         }
 464
 465         if (ka->sa.sa_flags & SA_RESTORER) {
 466                 restorer = ka->sa.sa_restorer;
 467         } else {
 468                 /* Return stub is in 32bit vsyscall page */
 469                 if (current->mm->context.vdso)
 470                         restorer = VDSO32_SYMBOL(current->mm->context.vdso,
 471                                                  sigreturn);
 472                 else
 473                         restorer = &frame->retcode;
 474         }
 475         err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
 476
 477         /*
 478          * These are actually not used anymore, but left because some
 479          * gdb versions depend on them as a marker.
 480          */
 481         err |= __copy_to_user(frame->retcode, &code, 8);
 482         if (err)
 483                 goto give_sigsegv;
 484
 485         /* Set up registers for signal handler */
 486         regs->sp = (unsigned long) frame;
 487         regs->ip = (unsigned long) ka->sa.sa_handler;
 488
 489         /* Make -mregparm=3 work */
 490         regs->ax = sig;
 491         regs->dx = 0;
 492         regs->cx = 0;
 493
 494         asm volatile("movl %0,%%ds" :: "r" (__USER32_DS));
 495         asm volatile("movl %0,%%es" :: "r" (__USER32_DS));
 496
 497         regs->cs = __USER32_CS;
 498         regs->ss = __USER32_DS;
 499
 500 #if DEBUG_SIG
 501         printk(KERN_DEBUG "SIG deliver (%s:%d): sp=%p pc=%lx ra=%u\n",
 502                current->comm, current->pid, frame, regs->ip, frame->pretcode);
 503 #endif
 504
 505         return 0;
 506
 507 give_sigsegv:
 508         force_sigsegv(sig, current);
 509         return -EFAULT;
 510 }
 511
 512 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 513                         compat_sigset_t *set, struct pt_regs *regs)
 514 {
 515         struct rt_sigframe __user *frame;
 516         void __user *restorer;
 517         int err = 0;
 518         void __user *fpstate = NULL;
 519
 520         /* __copy_to_user optimizes that into a single 8 byte store */
 521         static const struct {
 522                 u8 movl;
 523                 u32 val;
 524                 u16 int80;
 525                 u16 pad;
 526                 u8  pad2;
 527         } __attribute__((packed)) code = {
 528                 0xb8,
 529                 __NR_ia32_rt_sigreturn,
 530                 0x80cd,
 531                 0,
 532         };
 533
 534         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 535
 536         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 537                 goto give_sigsegv;
 538
 539         err |= __put_user(sig, &frame->sig);
 540         err |= __put_user(ptr_to_compat(&frame->info), &frame->pinfo);
 541         err |= __put_user(ptr_to_compat(&frame->uc), &frame->puc);
 542         err |= copy_siginfo_to_user32(&frame->info, info);
 543         if (err)
 544                 goto give_sigsegv;
 545
 546         /* Create the ucontext.  */
 547         if (cpu_has_xsave)
 548                 err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
 549         else
 550                 err |= __put_user(0, &frame->uc.uc_flags);
 551         err |= __put_user(0, &frame->uc.uc_link);
 552         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 553         err |= __put_user(sas_ss_flags(regs->sp),
 554                           &frame->uc.uc_stack.ss_flags);
 555         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 556         err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 557                                      regs, set->sig[0]);
 558         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 559         if (err)
 560                 goto give_sigsegv;
 561
 562         if (ka->sa.sa_flags & SA_RESTORER)
 563                 restorer = ka->sa.sa_restorer;
 564         else
 565                 restorer = VDSO32_SYMBOL(current->mm->context.vdso,
 566                                          rt_sigreturn);
 567         err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
 568
 569         /*
 570          * Not actually used anymore, but left because some gdb
 571          * versions need it.
 572          */
 573         err |= __copy_to_user(frame->retcode, &code, 8);
 574         if (err)
 575                 goto give_sigsegv;
 576
 577         /* Set up registers for signal handler */
 578         regs->sp = (unsigned long) frame;
 579         regs->ip = (unsigned long) ka->sa.sa_handler;
 580
 581         /* Make -mregparm=3 work */
 582         regs->ax = sig;
 583         regs->dx = (unsigned long) &frame->info;
 584         regs->cx = (unsigned long) &frame->uc;
 585
 586         /* Make -mregparm=3 work */
 587         regs->ax = sig;
 588         regs->dx = (unsigned long) &frame->info;
 589         regs->cx = (unsigned long) &frame->uc;
 590
 591         asm volatile("movl %0,%%ds" :: "r" (__USER32_DS));
 592         asm volatile("movl %0,%%es" :: "r" (__USER32_DS));
 593
 594         regs->cs = __USER32_CS;
 595         regs->ss = __USER32_DS;
 596
 597 #if DEBUG_SIG
 598         printk(KERN_DEBUG "SIG deliver (%s:%d): sp=%p pc=%lx ra=%u\n",
 599                current->comm, current->pid, frame, regs->ip, frame->pretcode);
 600 #endif
 601
 602         return 0;
 603
 604 give_sigsegv:
 605         force_sigsegv(sig, current);
 606         return -EFAULT;
 607 }