arch/cris/arch-v32/kernel/signal.c

   1 /*
   2  * Copyright (C) 2003, Axis Communications AB.
   3  */
   4
   5 #include <linux/sched.h>
   6 #include <linux/mm.h>
   7 #include <linux/slab.h>
   8 #include <linux/kernel.h>
   9 #include <linux/signal.h>
  10 #include <linux/errno.h>
  11 #include <linux/wait.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/unistd.h>
  14 #include <linux/stddef.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/vmalloc.h>
  17
  18 #include <asm/io.h>
  19 #include <asm/processor.h>
  20 #include <asm/ucontext.h>
  21 #include <asm/uaccess.h>
  22 #include <arch/ptrace.h>
  23 #include <arch/hwregs/cpu_vect.h>
  24
  25 extern unsigned long cris_signal_return_page;
  26
  27 /* Flag to check if a signal is blockable. */
  28 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  29
  30 /*
  31  * A syscall in CRIS is really a "break 13" instruction, which is 2
  32  * bytes. The registers is manipulated so upon return the instruction
  33  * will be executed again.
  34  *
  35  * This relies on that PC points to the instruction after the break call.
  36  */
  37 #define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->erp -= 2;
  38
  39 /* Signal frames. */
  40 struct signal_frame {
  41         struct sigcontext sc;
  42         unsigned long extramask[_NSIG_WORDS - 1];
  43         unsigned char retcode[8];       /* Trampoline code. */
  44 };
  45
  46 struct rt_signal_frame {
  47         struct siginfo *pinfo;
  48         void *puc;
  49         struct siginfo info;
  50         struct ucontext uc;
  51         unsigned char retcode[8];       /* Trampoline code. */
  52 };
  53
  54 void do_signal(int restart, struct pt_regs *regs);
  55 void keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
  56                       struct pt_regs *regs);
  57 /*
  58  * Swap in the new signal mask, and wait for a signal. Define some
  59  * dummy arguments to be able to reach the regs argument.
  60  */
  61 int
  62 sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof,
  63                long srp, struct pt_regs *regs)
  64 {
  65         mask &= _BLOCKABLE;
  66         spin_lock_irq(&current->sighand->siglock);
  67         current->saved_sigmask = current->blocked;
  68         siginitset(&current->blocked, mask);
  69         recalc_sigpending();
  70         spin_unlock_irq(&current->sighand->siglock);
  71         current->state = TASK_INTERRUPTIBLE;
  72         schedule();
  73         set_thread_flag(TIF_RESTORE_SIGMASK);
  74         return -ERESTARTNOHAND;
  75 }
  76
  77 int
  78 sys_sigaction(int signal, const struct old_sigaction *act,
  79               struct old_sigaction *oact)
  80 {
  81         int retval;
  82         struct k_sigaction newk;
  83         struct k_sigaction oldk;
  84
  85         if (act) {
  86                 old_sigset_t mask;
  87
  88                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  89                     __get_user(newk.sa.sa_handler, &act->sa_handler) ||
  90                     __get_user(newk.sa.sa_restorer, &act->sa_restorer))
  91                         return -EFAULT;
  92
  93                 __get_user(newk.sa.sa_flags, &act->sa_flags);
  94                 __get_user(mask, &act->sa_mask);
  95                 siginitset(&newk.sa.sa_mask, mask);
  96         }
  97
  98         retval = do_sigaction(signal, act ? &newk : NULL, oact ? &oldk : NULL);
  99
 100         if (!retval && oact) {
 101                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 102                     __put_user(oldk.sa.sa_handler, &oact->sa_handler) ||
 103                     __put_user(oldk.sa.sa_restorer, &oact->sa_restorer))
 104                         return -EFAULT;
 105
 106                 __put_user(oldk.sa.sa_flags, &oact->sa_flags);
 107                 __put_user(oldk.sa.sa_mask.sig[0], &oact->sa_mask);
 108         }
 109
 110         return retval;
 111 }
 112
 113 int
 114 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 115 {
 116         return do_sigaltstack(uss, uoss, rdusp());
 117 }
 118
 119 static int
 120 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 121 {
 122         unsigned int err = 0;
 123         unsigned long old_usp;
 124
 125         /* Always make any pending restarted system calls return -EINTR */
 126         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 127
 128         /*
 129          * Restore the registers from &sc->regs. sc is already checked
 130          * for VERIFY_READ since the signal_frame was previously
 131          * checked in sys_sigreturn().
 132          */
 133         if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
 134                 goto badframe;
 135
 136         /* Make that the user-mode flag is set. */
 137         regs->ccs |= (1 << (U_CCS_BITNR + CCS_SHIFT));
 138
 139         /* Restore the old USP. */
 140         err |= __get_user(old_usp, &sc->usp);
 141         wrusp(old_usp);
 142
 143         return err;
 144
 145 badframe:
 146         return 1;
 147 }
 148
 149 /* Define some dummy arguments to be able to reach the regs argument. */
 150 asmlinkage int
 151 sys_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp,
 152               struct pt_regs *regs)
 153 {
 154         sigset_t set;
 155         struct signal_frame __user *frame;
 156         unsigned long oldspc = regs->spc;
 157         unsigned long oldccs = regs->ccs;
 158
 159         frame = (struct signal_frame *) rdusp();
 160
 161         /*
 162          * Since the signal is stacked on a dword boundary, the frame
 163          * should be dword aligned here as well. It it's not, then the
 164          * user is trying some funny business.
 165          */
 166         if (((long)frame) & 3)
 167                 goto badframe;
 168
 169         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 170                 goto badframe;
 171
 172         if (__get_user(set.sig[0], &frame->sc.oldmask) ||
 173             (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1],
 174                                                  frame->extramask,
 175                                                  sizeof(frame->extramask))))
 176                 goto badframe;
 177
 178         sigdelsetmask(&set, ~_BLOCKABLE);
 179         spin_lock_irq(&current->sighand->siglock);
 180
 181         current->blocked = set;
 182
 183         recalc_sigpending();
 184         spin_unlock_irq(&current->sighand->siglock);
 185
 186         if (restore_sigcontext(regs, &frame->sc))
 187                 goto badframe;
 188
 189         keep_debug_flags(oldccs, oldspc, regs);
 190
 191         return regs->r10;
 192
 193 badframe:
 194         force_sig(SIGSEGV, current);
 195         return 0;
 196 }
 197
 198 /* Define some dummy variables to be able to reach the regs argument. */
 199 asmlinkage int
 200 sys_rt_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp,
 201                  struct pt_regs *regs)
 202 {
 203         sigset_t set;
 204         struct rt_signal_frame __user *frame;
 205         unsigned long oldspc = regs->spc;
 206         unsigned long oldccs = regs->ccs;
 207
 208         frame = (struct rt_signal_frame *) rdusp();
 209
 210         /*
 211          * Since the signal is stacked on a dword boundary, the frame
 212          * should be dword aligned here as well. It it's not, then the
 213          * user is trying some funny business.
 214          */
 215         if (((long)frame) & 3)
 216                 goto badframe;
 217
 218         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 219                 goto badframe;
 220
 221         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 222                 goto badframe;
 223
 224         sigdelsetmask(&set, ~_BLOCKABLE);
 225         spin_lock_irq(&current->sighand->siglock);
 226
 227         current->blocked = set;
 228
 229         recalc_sigpending();
 230         spin_unlock_irq(&current->sighand->siglock);
 231
 232         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 233                 goto badframe;
 234
 235         if (do_sigaltstack(&frame->uc.uc_stack, NULL, rdusp()) == -EFAULT)
 236                 goto badframe;
 237
 238         keep_debug_flags(oldccs, oldspc, regs);
 239
 240         return regs->r10;
 241
 242 badframe:
 243         force_sig(SIGSEGV, current);
 244         return 0;
 245 }
 246
 247 /* Setup a signal frame. */
 248 static int
 249 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 250                  unsigned long mask)
 251 {
 252         int err;
 253         unsigned long usp;
 254
 255         err = 0;
 256         usp = rdusp();
 257
 258         /*
 259          * Copy the registers. They are located first in sc, so it's
 260          * possible to use sc directly.
 261          */
 262         err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
 263
 264         err |= __put_user(mask, &sc->oldmask);
 265         err |= __put_user(usp, &sc->usp);
 266
 267         return err;
 268 }
 269
 270 /* Figure out where to put the new signal frame - usually on the stack. */
 271 static inline void __user *
 272 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 273 {
 274         unsigned long sp;
 275
 276         sp = rdusp();
 277
 278         /* This is the X/Open sanctioned signal stack switching. */
 279         if (ka->sa.sa_flags & SA_ONSTACK) {
 280                 if (!on_sig_stack(sp))
 281                         sp = current->sas_ss_sp + current->sas_ss_size;
 282         }
 283
 284         /* Make sure the frame is dword-aligned. */
 285         sp &= ~3;
 286
 287         return (void __user *)(sp - frame_size);
 288 }
 289
 290 /* Grab and setup a signal frame.
 291  *
 292  * Basically a lot of state-info is stacked, and arranged for the
 293  * user-mode program to return to the kernel using either a trampiline
 294  * which performs the syscall sigreturn(), or a provided user-mode
 295  * trampoline.
 296   */
 297 static int
 298 setup_frame(int sig, struct k_sigaction *ka,  sigset_t *set,
 299             struct pt_regs * regs)
 300 {
 301         int err;
 302         unsigned long return_ip;
 303         struct signal_frame __user *frame;
 304
 305         err = 0;
 306         frame = get_sigframe(ka, regs, sizeof(*frame));
 307
 308         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 309                 goto give_sigsegv;
 310
 311         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 312
 313         if (err)
 314                 goto give_sigsegv;
 315
 316         if (_NSIG_WORDS > 1) {
 317                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 318                                       sizeof(frame->extramask));
 319         }
 320
 321         if (err)
 322                 goto give_sigsegv;
 323
 324         /*
 325          * Set up to return from user-space. If provided, use a stub
 326          * already located in user-space.
 327          */
 328         if (ka->sa.sa_flags & SA_RESTORER) {
 329                 return_ip = (unsigned long)ka->sa.sa_restorer;
 330         } else {
 331                 /* Trampoline - the desired return ip is in the signal return page. */
 332                 return_ip = cris_signal_return_page;
 333
 334                 /*
 335                  * This is movu.w __NR_sigreturn, r9; break 13;
 336                  *
 337                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 338                  * reasons and because gdb uses it as a signature to notice
 339                  * signal handler stack frames.
 340                  */
 341                 err |= __put_user(0x9c5f,         (short __user*)(frame->retcode+0));
 342                 err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2));
 343                 err |= __put_user(0xe93d,         (short __user*)(frame->retcode+4));
 344         }
 345
 346         if (err)
 347                 goto give_sigsegv;
 348
 349         /*
 350          * Set up registers for signal handler.
 351          *
 352          * Where the code enters now.
 353          * Where the code enter later.
 354          * First argument, signo.
 355          */
 356         regs->erp = (unsigned long) ka->sa.sa_handler;
 357         regs->srp = return_ip;
 358         regs->r10 = sig;
 359
 360         /* Actually move the USP to reflect the stacked frame. */
 361         wrusp((unsigned long)frame);
 362
 363         return 0;
 364
 365 give_sigsegv:
 366         if (sig == SIGSEGV)
 367                 ka->sa.sa_handler = SIG_DFL;
 368
 369         force_sig(SIGSEGV, current);
 370         return -EFAULT;
 371 }
 372
 373 static int
 374 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 375                sigset_t *set, struct pt_regs * regs)
 376 {
 377         int err;
 378         unsigned long return_ip;
 379         struct rt_signal_frame __user *frame;
 380
 381         err = 0;
 382         frame = get_sigframe(ka, regs, sizeof(*frame));
 383
 384         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 385                 goto give_sigsegv;
 386
 387         /* TODO: what is the current->exec_domain stuff and invmap ? */
 388
 389         err |= __put_user(&frame->info, &frame->pinfo);
 390         err |= __put_user(&frame->uc, &frame->puc);
 391         err |= copy_siginfo_to_user(&frame->info, info);
 392
 393         if (err)
 394                 goto give_sigsegv;
 395
 396         /* Clear all the bits of the ucontext we don't use.  */
 397         err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
 398         err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 399         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 400
 401         if (err)
 402                 goto give_sigsegv;
 403
 404         /*
 405          * Set up to return from user-space. If provided, use a stub
 406          * already located in user-space.
 407          */
 408         if (ka->sa.sa_flags & SA_RESTORER) {
 409                 return_ip = (unsigned long) ka->sa.sa_restorer;
 410         } else {
 411                 /* Trampoline - the desired return ip is in the signal return page. */
 412                 return_ip = cris_signal_return_page + 6;
 413
 414                 /*
 415                  * This is movu.w __NR_rt_sigreturn, r9; break 13;
 416                  *
 417                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 418                  * reasons and because gdb uses it as a signature to notice
 419                  * signal handler stack frames.
 420                  */
 421                 err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
 422
 423                 err |= __put_user(__NR_rt_sigreturn,
 424                                   (short __user*)(frame->retcode+2));
 425
 426                 err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
 427         }
 428
 429         if (err)
 430                 goto give_sigsegv;
 431
 432         /*
 433          * Set up registers for signal handler.
 434          *
 435          * Where the code enters now.
 436          * Where the code enters later.
 437          * First argument is signo.
 438          * Second argument is (siginfo_t *).
 439          * Third argument is unused.
 440          */
 441         regs->erp = (unsigned long) ka->sa.sa_handler;
 442         regs->srp = return_ip;
 443         regs->r10 = sig;
 444         regs->r11 = (unsigned long) &frame->info;
 445         regs->r12 = 0;
 446
 447         /* Actually move the usp to reflect the stacked frame. */
 448         wrusp((unsigned long)frame);
 449
 450         return 0;
 451
 452 give_sigsegv:
 453         if (sig == SIGSEGV)
 454                 ka->sa.sa_handler = SIG_DFL;
 455
 456         force_sig(SIGSEGV, current);
 457         return -EFAULT;
 458 }
 459
 460 /* Invoke a signal handler to, well, handle the signal. */
 461 static inline int
 462 handle_signal(int canrestart, unsigned long sig,
 463               siginfo_t *info, struct k_sigaction *ka,
 464               sigset_t *oldset, struct pt_regs * regs)
 465 {
 466         int ret;
 467
 468         /* Check if this got called from a system call. */
 469         if (canrestart) {
 470                 /* If so, check system call restarting. */
 471                 switch (regs->r10) {
 472                         case -ERESTART_RESTARTBLOCK:
 473                         case -ERESTARTNOHAND:
 474                                 /*
 475                                  * This means that the syscall should
 476                                  * only be restarted if there was no
 477                                  * handler for the signal, and since
 478                                  * this point isn't reached unless
 479                                  * there is a handler, there's no need
 480                                  * to restart.
 481                                  */
 482                                 regs->r10 = -EINTR;
 483                                 break;
 484
 485                         case -ERESTARTSYS:
 486                                 /*
 487                                  * This means restart the syscall if
 488                                  * there is no handler, or the handler
 489                                  * was registered with SA_RESTART.
 490                                  */
 491                                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 492                                         regs->r10 = -EINTR;
 493                                         break;
 494                                 }
 495
 496                                 /* Fall through. */
 497
 498                         case -ERESTARTNOINTR:
 499                                 /*
 500                                  * This means that the syscall should
 501                                  * be called again after the signal
 502                                  * handler returns.
 503                                  */
 504                                 RESTART_CRIS_SYS(regs);
 505                                 break;
 506                 }
 507         }
 508
 509         /* Set up the stack frame. */
 510         if (ka->sa.sa_flags & SA_SIGINFO)
 511                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 512         else
 513                 ret = setup_frame(sig, ka, oldset, regs);
 514
 515         if (ka->sa.sa_flags & SA_ONESHOT)
 516                 ka->sa.sa_handler = SIG_DFL;
 517
 518         if (ret == 0) {
 519                 spin_lock_irq(&current->sighand->siglock);
 520                 sigorsets(&current->blocked, &current->blocked,
 521                         &ka->sa.sa_mask);
 522                 if (!(ka->sa.sa_flags & SA_NODEFER))
 523                         sigaddset(&current->blocked, sig);
 524                 recalc_sigpending();
 525                 spin_unlock_irq(&current->sighand->siglock);
 526         }
 527
 528         return ret;
 529 }
 530
 531 /*
 532  * Note that 'init' is a special process: it doesn't get signals it doesn't
 533  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 534  * mistake.
 535  *
 536  * Also note that the regs structure given here as an argument, is the latest
 537  * pushed pt_regs. It may or may not be the same as the first pushed registers
 538  * when the initial usermode->kernelmode transition took place. Therefore
 539  * we can use user_mode(regs) to see if we came directly from kernel or user
 540  * mode below.
 541  */
 542 void
 543 do_signal(int canrestart, struct pt_regs *regs)
 544 {
 545         int signr;
 546         siginfo_t info;
 547         struct k_sigaction ka;
 548         sigset_t *oldset;
 549
 550         /*
 551          * The common case should go fast, which is why this point is
 552          * reached from kernel-mode. If that's the case, just return
 553          * without doing anything.
 554          */
 555         if (!user_mode(regs))
 556                 return;
 557
 558         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 559                 oldset = &current->saved_sigmask;
 560         else
 561                 oldset = &current->blocked;
 562
 563         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 564
 565         if (signr > 0) {
 566                 /* Whee!  Actually deliver the signal.  */
 567                 if (handle_signal(canrestart, signr, &info, &ka,
 568                                 oldset, regs)) {
 569                         /* a signal was successfully delivered; the saved
 570                          * sigmask will have been stored in the signal frame,
 571                          * and will be restored by sigreturn, so we can simply
 572                          * clear the TIF_RESTORE_SIGMASK flag */
 573                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 574                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 575                 }
 576
 577                 return;
 578         }
 579
 580         /* Got here from a system call? */
 581         if (canrestart) {
 582                 /* Restart the system call - no handlers present. */
 583                 if (regs->r10 == -ERESTARTNOHAND ||
 584                     regs->r10 == -ERESTARTSYS ||
 585                     regs->r10 == -ERESTARTNOINTR) {
 586                         RESTART_CRIS_SYS(regs);
 587                 }
 588
 589                 if (regs->r10 == -ERESTART_RESTARTBLOCK){
 590                         regs->r9 = __NR_restart_syscall;
 591                         regs->erp -= 2;
 592                 }
 593         }
 594
 595         /* if there's no signal to deliver, we just put the saved sigmask
 596          * back */
 597         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 598                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 599                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 600         }
 601 }
 602
 603 asmlinkage void
 604 ugdb_trap_user(struct thread_info *ti, int sig)
 605 {
 606         if (((user_regs(ti)->exs & 0xff00) >> 8) != SINGLE_STEP_INTR_VECT) {
 607                 /* Zero single-step PC if the reason we stopped wasn't a single
 608                    step exception. This is to avoid relying on it when it isn't
 609                    reliable. */
 610                 user_regs(ti)->spc = 0;
 611         }
 612         /* FIXME: Filter out false h/w breakpoint hits (i.e. EDA
 613            not within any configured h/w breakpoint range). Synchronize with
 614            what already exists for kernel debugging.  */
 615         if (((user_regs(ti)->exs & 0xff00) >> 8) == BREAK_8_INTR_VECT) {
 616                 /* Break 8: subtract 2 from ERP unless in a delay slot. */
 617                 if (!(user_regs(ti)->erp & 0x1))
 618                         user_regs(ti)->erp -= 2;
 619         }
 620         sys_kill(ti->task->pid, sig);
 621 }
 622
 623 void
 624 keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
 625                  struct pt_regs *regs)
 626 {
 627         if (oldccs & (1 << Q_CCS_BITNR)) {
 628                 /* Pending single step due to single-stepping the break 13
 629                    in the signal trampoline: keep the Q flag. */
 630                 regs->ccs |= (1 << Q_CCS_BITNR);
 631                 /* S flag should be set - complain if it's not. */
 632                 if (!(oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT)))) {
 633                         printk("Q flag but no S flag?");
 634                 }
 635                 regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
 636                 /* Assume the SPC is valid and interesting. */
 637                 regs->spc = oldspc;
 638
 639         } else if (oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT))) {
 640                 /* If a h/w bp was set in the signal handler we need
 641                    to keep the S flag. */
 642                 regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
 643                 /* Don't keep the old SPC though; if we got here due to
 644                    a single-step, the Q flag should have been set. */
 645         } else if (regs->spc) {
 646                 /* If we were single-stepping *before* the signal was taken,
 647                    we don't want to restore that state now, because GDB will
 648                    have forgotten all about it. */
 649                 regs->spc = 0;
 650                 regs->ccs &= ~(1 << (S_CCS_BITNR + CCS_SHIFT));
 651         }
 652 }
 653
 654 /* Set up the trampolines on the signal return page. */
 655 int __init
 656 cris_init_signal(void)
 657 {
 658         u16* data = kmalloc(PAGE_SIZE, GFP_KERNEL);
 659
 660         /* This is movu.w __NR_sigreturn, r9; break 13; */
 661         data[0] = 0x9c5f;
 662         data[1] = __NR_sigreturn;
 663         data[2] = 0xe93d;
 664         /* This is movu.w __NR_rt_sigreturn, r9; break 13; */
 665         data[3] = 0x9c5f;
 666         data[4] = __NR_rt_sigreturn;
 667         data[5] = 0xe93d;
 668
 669         /* Map to userspace with appropriate permissions (no write access...) */
 670         cris_signal_return_page = (unsigned long)
 671           __ioremap_prot(virt_to_phys(data), PAGE_SIZE, PAGE_SIGNAL_TRAMPOLINE);
 672
 673         return 0;
 674 }
 675
 676 __initcall(cris_init_signal);