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