arch/sh/kernel/signal.c

   1 /*
   2  *  linux/arch/sh/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   7  *
   8  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
   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/tty.h>
  22 #include <linux/elf.h>
  23 #include <linux/personality.h>
  24 #include <linux/binfmts.h>
  25 #include <linux/freezer.h>
  26 #include <linux/io.h>
  27 #include <asm/system.h>
  28 #include <asm/ucontext.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/cacheflush.h>
  32
  33 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  34
  35 /*
  36  * Atomically swap in the new signal mask, and wait for a signal.
  37  */
  38 asmlinkage int
  39 sys_sigsuspend(old_sigset_t mask,
  40                unsigned long r5, unsigned long r6, unsigned long r7,
  41                struct pt_regs __regs)
  42 {
  43         mask &= _BLOCKABLE;
  44         spin_lock_irq(&current->sighand->siglock);
  45         current->saved_sigmask = current->blocked;
  46         siginitset(&current->blocked, mask);
  47         recalc_sigpending();
  48         spin_unlock_irq(&current->sighand->siglock);
  49
  50         current->state = TASK_INTERRUPTIBLE;
  51         schedule();
  52         set_thread_flag(TIF_RESTORE_SIGMASK);
  53         return -ERESTARTNOHAND;
  54 }
  55
  56 asmlinkage int
  57 sys_sigaction(int sig, const struct old_sigaction __user *act,
  58               struct old_sigaction __user *oact)
  59 {
  60         struct k_sigaction new_ka, old_ka;
  61         int ret;
  62
  63         if (act) {
  64                 old_sigset_t mask;
  65                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  66                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  67                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  68                         return -EFAULT;
  69                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  70                 __get_user(mask, &act->sa_mask);
  71                 siginitset(&new_ka.sa.sa_mask, mask);
  72         }
  73
  74         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  75
  76         if (!ret && oact) {
  77                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  78                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  79                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  80                         return -EFAULT;
  81                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  82                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  83         }
  84
  85         return ret;
  86 }
  87
  88 asmlinkage int
  89 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  90                 unsigned long r6, unsigned long r7,
  91                 struct pt_regs __regs)
  92 {
  93         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
  94
  95         return do_sigaltstack(uss, uoss, regs->regs[15]);
  96 }
  97
  98
  99 /*
 100  * Do a signal return; undo the signal stack.
 101  */
 102
 103 #define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */
 104 #if defined(CONFIG_CPU_SH2)
 105 #define TRAP_NOARG 0xc320               /* Syscall w/no args (NR in R3) */
 106 #else
 107 #define TRAP_NOARG 0xc310               /* Syscall w/no args (NR in R3) */
 108 #endif
 109 #define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */
 110
 111 struct sigframe
 112 {
 113         struct sigcontext sc;
 114         unsigned long extramask[_NSIG_WORDS-1];
 115         u16 retcode[8];
 116 };
 117
 118 struct rt_sigframe
 119 {
 120         struct siginfo info;
 121         struct ucontext uc;
 122         u16 retcode[8];
 123 };
 124
 125 #ifdef CONFIG_SH_FPU
 126 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
 127 {
 128         struct task_struct *tsk = current;
 129
 130         if (!(current_cpu_data.flags & CPU_HAS_FPU))
 131                 return 0;
 132
 133         set_used_math();
 134         return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],
 135                                 sizeof(long)*(16*2+2));
 136 }
 137
 138 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
 139                                       struct pt_regs *regs)
 140 {
 141         struct task_struct *tsk = current;
 142
 143         if (!(current_cpu_data.flags & CPU_HAS_FPU))
 144                 return 0;
 145
 146         if (!used_math()) {
 147                 __put_user(0, &sc->sc_ownedfp);
 148                 return 0;
 149         }
 150
 151         __put_user(1, &sc->sc_ownedfp);
 152
 153         /* This will cause a "finit" to be triggered by the next
 154            attempted FPU operation by the 'current' process.
 155            */
 156         clear_used_math();
 157
 158         unlazy_fpu(tsk, regs);
 159         return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,
 160                               sizeof(long)*(16*2+2));
 161 }
 162 #endif /* CONFIG_SH_FPU */
 163
 164 static int
 165 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
 166 {
 167         unsigned int err = 0;
 168
 169 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
 170                         COPY(regs[1]);
 171         COPY(regs[2]);  COPY(regs[3]);
 172         COPY(regs[4]);  COPY(regs[5]);
 173         COPY(regs[6]);  COPY(regs[7]);
 174         COPY(regs[8]);  COPY(regs[9]);
 175         COPY(regs[10]); COPY(regs[11]);
 176         COPY(regs[12]); COPY(regs[13]);
 177         COPY(regs[14]); COPY(regs[15]);
 178         COPY(gbr);      COPY(mach);
 179         COPY(macl);     COPY(pr);
 180         COPY(sr);       COPY(pc);
 181 #undef COPY
 182
 183 #ifdef CONFIG_SH_FPU
 184         if (current_cpu_data.flags & CPU_HAS_FPU) {
 185                 int owned_fp;
 186                 struct task_struct *tsk = current;
 187
 188                 regs->sr |= SR_FD; /* Release FPU */
 189                 clear_fpu(tsk, regs);
 190                 clear_used_math();
 191                 __get_user (owned_fp, &sc->sc_ownedfp);
 192                 if (owned_fp)
 193                         err |= restore_sigcontext_fpu(sc);
 194         }
 195 #endif
 196
 197         regs->tra = -1;         /* disable syscall checks */
 198         err |= __get_user(*r0_p, &sc->sc_regs[0]);
 199         return err;
 200 }
 201
 202 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
 203                              unsigned long r6, unsigned long r7,
 204                              struct pt_regs __regs)
 205 {
 206         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 207         struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
 208         sigset_t set;
 209         int r0;
 210
 211         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 212                 goto badframe;
 213
 214         if (__get_user(set.sig[0], &frame->sc.oldmask)
 215             || (_NSIG_WORDS > 1
 216                 && __copy_from_user(&set.sig[1], &frame->extramask,
 217                                     sizeof(frame->extramask))))
 218                 goto badframe;
 219
 220         sigdelsetmask(&set, ~_BLOCKABLE);
 221
 222         spin_lock_irq(&current->sighand->siglock);
 223         current->blocked = set;
 224         recalc_sigpending();
 225         spin_unlock_irq(&current->sighand->siglock);
 226
 227         if (restore_sigcontext(regs, &frame->sc, &r0))
 228                 goto badframe;
 229         return r0;
 230
 231 badframe:
 232         force_sig(SIGSEGV, current);
 233         return 0;
 234 }
 235
 236 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
 237                                 unsigned long r6, unsigned long r7,
 238                                 struct pt_regs __regs)
 239 {
 240         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 241         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
 242         sigset_t set;
 243         stack_t st;
 244         int r0;
 245
 246         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 247                 goto badframe;
 248
 249         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 250                 goto badframe;
 251
 252         sigdelsetmask(&set, ~_BLOCKABLE);
 253         spin_lock_irq(&current->sighand->siglock);
 254         current->blocked = set;
 255         recalc_sigpending();
 256         spin_unlock_irq(&current->sighand->siglock);
 257
 258         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 259                 goto badframe;
 260
 261         if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
 262                 goto badframe;
 263         /* It is more difficult to avoid calling this function than to
 264            call it and ignore errors.  */
 265         do_sigaltstack((const stack_t __user *)&st, NULL, (unsigned long)frame);
 266
 267         return r0;
 268
 269 badframe:
 270         force_sig(SIGSEGV, current);
 271         return 0;
 272 }
 273
 274 /*
 275  * Set up a signal frame.
 276  */
 277
 278 static int
 279 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 280                  unsigned long mask)
 281 {
 282         int err = 0;
 283
 284 #define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)
 285         COPY(regs[0]);  COPY(regs[1]);
 286         COPY(regs[2]);  COPY(regs[3]);
 287         COPY(regs[4]);  COPY(regs[5]);
 288         COPY(regs[6]);  COPY(regs[7]);
 289         COPY(regs[8]);  COPY(regs[9]);
 290         COPY(regs[10]); COPY(regs[11]);
 291         COPY(regs[12]); COPY(regs[13]);
 292         COPY(regs[14]); COPY(regs[15]);
 293         COPY(gbr);      COPY(mach);
 294         COPY(macl);     COPY(pr);
 295         COPY(sr);       COPY(pc);
 296 #undef COPY
 297
 298 #ifdef CONFIG_SH_FPU
 299         err |= save_sigcontext_fpu(sc, regs);
 300 #endif
 301
 302         /* non-iBCS2 extensions.. */
 303         err |= __put_user(mask, &sc->oldmask);
 304
 305         return err;
 306 }
 307
 308 /*
 309  * Determine which stack to use..
 310  */
 311 static inline void __user *
 312 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 313 {
 314         if (ka->sa.sa_flags & SA_ONSTACK) {
 315                 if (sas_ss_flags(sp) == 0)
 316                         sp = current->sas_ss_sp + current->sas_ss_size;
 317         }
 318
 319         return (void __user *)((sp - frame_size) & -8ul);
 320 }
 321
 322 /* These symbols are defined with the addresses in the vsyscall page.
 323    See vsyscall-trapa.S.  */
 324 extern void __user __kernel_sigreturn;
 325 extern void __user __kernel_rt_sigreturn;
 326
 327 static int setup_frame(int sig, struct k_sigaction *ka,
 328                         sigset_t *set, struct pt_regs *regs)
 329 {
 330         struct sigframe __user *frame;
 331         int err = 0;
 332         int signal;
 333
 334         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 335
 336         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 337                 goto give_sigsegv;
 338
 339         signal = current_thread_info()->exec_domain
 340                 && current_thread_info()->exec_domain->signal_invmap
 341                 && sig < 32
 342                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 343                 : sig;
 344
 345         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 346
 347         if (_NSIG_WORDS > 1)
 348                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 349                                       sizeof(frame->extramask));
 350
 351         /* Set up to return from userspace.  If provided, use a stub
 352            already in userspace.  */
 353         if (ka->sa.sa_flags & SA_RESTORER) {
 354                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 355 #ifdef CONFIG_VSYSCALL
 356         } else if (likely(current->mm->context.vdso)) {
 357                 regs->pr = VDSO_SYM(&__kernel_sigreturn);
 358 #endif
 359         } else {
 360                 /* Generate return code (system call to sigreturn) */
 361                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 362                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 363                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 364                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 365                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 366                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 367                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 368                 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
 369                 regs->pr = (unsigned long) frame->retcode;
 370         }
 371
 372         if (err)
 373                 goto give_sigsegv;
 374
 375         /* Set up registers for signal handler */
 376         regs->regs[15] = (unsigned long) frame;
 377         regs->regs[4] = signal; /* Arg for signal handler */
 378         regs->regs[5] = 0;
 379         regs->regs[6] = (unsigned long) &frame->sc;
 380         regs->pc = (unsigned long) ka->sa.sa_handler;
 381
 382         set_fs(USER_DS);
 383
 384         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 385                  current->comm, current->pid, frame, regs->pc, regs->pr);
 386
 387         flush_cache_sigtramp(regs->pr);
 388
 389         if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
 390                 flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
 391
 392         return 0;
 393
 394 give_sigsegv:
 395         force_sigsegv(sig, current);
 396         return -EFAULT;
 397 }
 398
 399 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 400                            sigset_t *set, struct pt_regs *regs)
 401 {
 402         struct rt_sigframe __user *frame;
 403         int err = 0;
 404         int signal;
 405
 406         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 407
 408         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 409                 goto give_sigsegv;
 410
 411         signal = current_thread_info()->exec_domain
 412                 && current_thread_info()->exec_domain->signal_invmap
 413                 && sig < 32
 414                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 415                 : sig;
 416
 417         err |= copy_siginfo_to_user(&frame->info, info);
 418
 419         /* Create the ucontext.  */
 420         err |= __put_user(0, &frame->uc.uc_flags);
 421         err |= __put_user(0, &frame->uc.uc_link);
 422         err |= __put_user((void *)current->sas_ss_sp,
 423                           &frame->uc.uc_stack.ss_sp);
 424         err |= __put_user(sas_ss_flags(regs->regs[15]),
 425                           &frame->uc.uc_stack.ss_flags);
 426         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 427         err |= setup_sigcontext(&frame->uc.uc_mcontext,
 428                                 regs, set->sig[0]);
 429         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 430
 431         /* Set up to return from userspace.  If provided, use a stub
 432            already in userspace.  */
 433         if (ka->sa.sa_flags & SA_RESTORER) {
 434                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 435 #ifdef CONFIG_VSYSCALL
 436         } else if (likely(current->mm->context.vdso)) {
 437                 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
 438 #endif
 439         } else {
 440                 /* Generate return code (system call to rt_sigreturn) */
 441                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 442                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 443                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 444                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 445                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 446                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 447                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 448                 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
 449                 regs->pr = (unsigned long) frame->retcode;
 450         }
 451
 452         if (err)
 453                 goto give_sigsegv;
 454
 455         /* Set up registers for signal handler */
 456         regs->regs[15] = (unsigned long) frame;
 457         regs->regs[4] = signal; /* Arg for signal handler */
 458         regs->regs[5] = (unsigned long) &frame->info;
 459         regs->regs[6] = (unsigned long) &frame->uc;
 460         regs->pc = (unsigned long) ka->sa.sa_handler;
 461
 462         set_fs(USER_DS);
 463
 464         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 465                  current->comm, current->pid, frame, regs->pc, regs->pr);
 466
 467         flush_cache_sigtramp(regs->pr);
 468
 469         if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
 470                 flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
 471
 472         return 0;
 473
 474 give_sigsegv:
 475         force_sigsegv(sig, current);
 476         return -EFAULT;
 477 }
 478
 479 /*
 480  * OK, we're invoking a handler
 481  */
 482
 483 static int
 484 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 485               sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0)
 486 {
 487         int ret;
 488
 489         /* Are we from a system call? */
 490         if (regs->tra >= 0) {
 491                 /* If so, check system call restarting.. */
 492                 switch (regs->regs[0]) {
 493                         case -ERESTART_RESTARTBLOCK:
 494                         case -ERESTARTNOHAND:
 495                                 regs->regs[0] = -EINTR;
 496                                 break;
 497
 498                         case -ERESTARTSYS:
 499                                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 500                                         regs->regs[0] = -EINTR;
 501                                         break;
 502                                 }
 503                         /* fallthrough */
 504                         case -ERESTARTNOINTR:
 505                                 regs->regs[0] = save_r0;
 506                                 regs->pc -= instruction_size(
 507                                                 ctrl_inw(regs->pc - 4));
 508                                 break;
 509                 }
 510 #ifdef CONFIG_GUSA
 511         } else {
 512                 /* gUSA handling */
 513                 preempt_disable();
 514
 515                 if (regs->regs[15] >= 0xc0000000) {
 516                         int offset = (int)regs->regs[15];
 517
 518                         /* Reset stack pointer: clear critical region mark */
 519                         regs->regs[15] = regs->regs[1];
 520                         if (regs->pc < regs->regs[0])
 521                                 /* Go to rewind point #1 */
 522                                 regs->pc = regs->regs[0] + offset -
 523                                         instruction_size(ctrl_inw(regs->pc-4));
 524                 }
 525
 526                 preempt_enable_no_resched();
 527 #endif
 528         }
 529
 530         /* Set up the stack frame */
 531         if (ka->sa.sa_flags & SA_SIGINFO)
 532                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 533         else
 534                 ret = setup_frame(sig, ka, oldset, regs);
 535
 536         if (ka->sa.sa_flags & SA_ONESHOT)
 537                 ka->sa.sa_handler = SIG_DFL;
 538
 539         if (ret == 0) {
 540                 spin_lock_irq(&current->sighand->siglock);
 541                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 542                 if (!(ka->sa.sa_flags & SA_NODEFER))
 543                         sigaddset(&current->blocked,sig);
 544                 recalc_sigpending();
 545                 spin_unlock_irq(&current->sighand->siglock);
 546         }
 547
 548         return ret;
 549 }
 550
 551 /*
 552  * Note that 'init' is a special process: it doesn't get signals it doesn't
 553  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 554  * mistake.
 555  *
 556  * Note that we go through the signals twice: once to check the signals that
 557  * the kernel can handle, and then we build all the user-level signal handling
 558  * stack-frames in one go after that.
 559  */
 560 static void do_signal(struct pt_regs *regs, unsigned int save_r0)
 561 {
 562         siginfo_t info;
 563         int signr;
 564         struct k_sigaction ka;
 565         sigset_t *oldset;
 566
 567         /*
 568          * We want the common case to go fast, which
 569          * is why we may in certain cases get here from
 570          * kernel mode. Just return without doing anything
 571          * if so.
 572          */
 573         if (!user_mode(regs))
 574                 return;
 575
 576         if (try_to_freeze())
 577                 goto no_signal;
 578
 579         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 580                 oldset = &current->saved_sigmask;
 581         else
 582                 oldset = &current->blocked;
 583
 584         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 585         if (signr > 0) {
 586                 /* Whee!  Actually deliver the signal.  */
 587                 if (handle_signal(signr, &ka, &info, oldset,
 588                                   regs, save_r0) == 0) {
 589                         /* a signal was successfully delivered; the saved
 590                          * sigmask will have been stored in the signal frame,
 591                          * and will be restored by sigreturn, so we can simply
 592                          * clear the TIF_RESTORE_SIGMASK flag */
 593                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 594                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 595                 }
 596
 597                 return;
 598         }
 599
 600  no_signal:
 601         /* Did we come from a system call? */
 602         if (regs->tra >= 0) {
 603                 /* Restart the system call - no handlers present */
 604                 if (regs->regs[0] == -ERESTARTNOHAND ||
 605                     regs->regs[0] == -ERESTARTSYS ||
 606                     regs->regs[0] == -ERESTARTNOINTR) {
 607                         regs->regs[0] = save_r0;
 608                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 609                 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
 610                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 611                         regs->regs[3] = __NR_restart_syscall;
 612                 }
 613         }
 614
 615         /* if there's no signal to deliver, we just put the saved sigmask
 616          * back */
 617         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 618                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 619                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 620         }
 621 }
 622
 623 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
 624                                  __u32 thread_info_flags)
 625 {
 626         /* deal with pending signal delivery */
 627         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 628                 do_signal(regs, save_r0);
 629 }