arch/sh/kernel/signal_32.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 <linux/tracehook.h>
  28 #include <asm/system.h>
  29 #include <asm/ucontext.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/cacheflush.h>
  33 #include <asm/syscalls.h>
  34 #include <asm/fpu.h>
  35
  36 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  37
  38 struct fdpic_func_descriptor {
  39         unsigned long   text;
  40         unsigned long   GOT;
  41 };
  42
  43 /*
  44  * Atomically swap in the new signal mask, and wait for a signal.
  45  */
  46 asmlinkage int
  47 sys_sigsuspend(old_sigset_t mask,
  48                unsigned long r5, unsigned long r6, unsigned long r7,
  49                struct pt_regs __regs)
  50 {
  51         mask &= _BLOCKABLE;
  52         spin_lock_irq(&current->sighand->siglock);
  53         current->saved_sigmask = current->blocked;
  54         siginitset(&current->blocked, mask);
  55         recalc_sigpending();
  56         spin_unlock_irq(&current->sighand->siglock);
  57
  58         current->state = TASK_INTERRUPTIBLE;
  59         schedule();
  60         set_thread_flag(TIF_RESTORE_SIGMASK);
  61         return -ERESTARTNOHAND;
  62 }
  63
  64 asmlinkage int
  65 sys_sigaction(int sig, const struct old_sigaction __user *act,
  66               struct old_sigaction __user *oact)
  67 {
  68         struct k_sigaction new_ka, old_ka;
  69         int ret;
  70
  71         if (act) {
  72                 old_sigset_t mask;
  73                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  74                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  75                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  76                         return -EFAULT;
  77                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  78                 __get_user(mask, &act->sa_mask);
  79                 siginitset(&new_ka.sa.sa_mask, mask);
  80         }
  81
  82         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  83
  84         if (!ret && oact) {
  85                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  86                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  87                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  88                         return -EFAULT;
  89                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  90                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  91         }
  92
  93         return ret;
  94 }
  95
  96 asmlinkage int
  97 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  98                 unsigned long r6, unsigned long r7,
  99                 struct pt_regs __regs)
 100 {
 101         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 102
 103         return do_sigaltstack(uss, uoss, regs->regs[15]);
 104 }
 105
 106
 107 /*
 108  * Do a signal return; undo the signal stack.
 109  */
 110
 111 #define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */
 112 #if defined(CONFIG_CPU_SH2)
 113 #define TRAP_NOARG 0xc320               /* Syscall w/no args (NR in R3) */
 114 #else
 115 #define TRAP_NOARG 0xc310               /* Syscall w/no args (NR in R3) */
 116 #endif
 117 #define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */
 118
 119 struct sigframe
 120 {
 121         struct sigcontext sc;
 122         unsigned long extramask[_NSIG_WORDS-1];
 123         u16 retcode[8];
 124 };
 125
 126 struct rt_sigframe
 127 {
 128         struct siginfo info;
 129         struct ucontext uc;
 130         u16 retcode[8];
 131 };
 132
 133 #ifdef CONFIG_SH_FPU
 134 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
 135 {
 136         struct task_struct *tsk = current;
 137
 138         if (!(current_cpu_data.flags & CPU_HAS_FPU))
 139                 return 0;
 140
 141         set_used_math();
 142         return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],
 143                                 sizeof(long)*(16*2+2));
 144 }
 145
 146 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
 147                                       struct pt_regs *regs)
 148 {
 149         struct task_struct *tsk = current;
 150
 151         if (!(current_cpu_data.flags & CPU_HAS_FPU))
 152                 return 0;
 153
 154         if (!used_math()) {
 155                 __put_user(0, &sc->sc_ownedfp);
 156                 return 0;
 157         }
 158
 159         __put_user(1, &sc->sc_ownedfp);
 160
 161         /* This will cause a "finit" to be triggered by the next
 162            attempted FPU operation by the 'current' process.
 163            */
 164         clear_used_math();
 165
 166         unlazy_fpu(tsk, regs);
 167         return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,
 168                               sizeof(long)*(16*2+2));
 169 }
 170 #endif /* CONFIG_SH_FPU */
 171
 172 static int
 173 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
 174 {
 175         unsigned int err = 0;
 176
 177 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
 178                         COPY(regs[1]);
 179         COPY(regs[2]);  COPY(regs[3]);
 180         COPY(regs[4]);  COPY(regs[5]);
 181         COPY(regs[6]);  COPY(regs[7]);
 182         COPY(regs[8]);  COPY(regs[9]);
 183         COPY(regs[10]); COPY(regs[11]);
 184         COPY(regs[12]); COPY(regs[13]);
 185         COPY(regs[14]); COPY(regs[15]);
 186         COPY(gbr);      COPY(mach);
 187         COPY(macl);     COPY(pr);
 188         COPY(sr);       COPY(pc);
 189 #undef COPY
 190
 191 #ifdef CONFIG_SH_FPU
 192         if (current_cpu_data.flags & CPU_HAS_FPU) {
 193                 int owned_fp;
 194                 struct task_struct *tsk = current;
 195
 196                 regs->sr |= SR_FD; /* Release FPU */
 197                 clear_fpu(tsk, regs);
 198                 clear_used_math();
 199                 __get_user (owned_fp, &sc->sc_ownedfp);
 200                 if (owned_fp)
 201                         err |= restore_sigcontext_fpu(sc);
 202         }
 203 #endif
 204
 205         regs->tra = -1;         /* disable syscall checks */
 206         err |= __get_user(*r0_p, &sc->sc_regs[0]);
 207         return err;
 208 }
 209
 210 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
 211                              unsigned long r6, unsigned long r7,
 212                              struct pt_regs __regs)
 213 {
 214         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 215         struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
 216         sigset_t set;
 217         int r0;
 218
 219         /* Always make any pending restarted system calls return -EINTR */
 220         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 221
 222         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 223                 goto badframe;
 224
 225         if (__get_user(set.sig[0], &frame->sc.oldmask)
 226             || (_NSIG_WORDS > 1
 227                 && __copy_from_user(&set.sig[1], &frame->extramask,
 228                                     sizeof(frame->extramask))))
 229                 goto badframe;
 230
 231         sigdelsetmask(&set, ~_BLOCKABLE);
 232
 233         spin_lock_irq(&current->sighand->siglock);
 234         current->blocked = set;
 235         recalc_sigpending();
 236         spin_unlock_irq(&current->sighand->siglock);
 237
 238         if (restore_sigcontext(regs, &frame->sc, &r0))
 239                 goto badframe;
 240         return r0;
 241
 242 badframe:
 243         force_sig(SIGSEGV, current);
 244         return 0;
 245 }
 246
 247 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
 248                                 unsigned long r6, unsigned long r7,
 249                                 struct pt_regs __regs)
 250 {
 251         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 252         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
 253         sigset_t set;
 254         int r0;
 255
 256         /* Always make any pending restarted system calls return -EINTR */
 257         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 258
 259         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 260                 goto badframe;
 261
 262         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 263                 goto badframe;
 264
 265         sigdelsetmask(&set, ~_BLOCKABLE);
 266         spin_lock_irq(&current->sighand->siglock);
 267         current->blocked = set;
 268         recalc_sigpending();
 269         spin_unlock_irq(&current->sighand->siglock);
 270
 271         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 272                 goto badframe;
 273
 274         if (do_sigaltstack(&frame->uc.uc_stack, NULL,
 275                            regs->regs[15]) == -EFAULT)
 276                 goto badframe;
 277
 278         return r0;
 279
 280 badframe:
 281         force_sig(SIGSEGV, current);
 282         return 0;
 283 }
 284
 285 /*
 286  * Set up a signal frame.
 287  */
 288
 289 static int
 290 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 291                  unsigned long mask)
 292 {
 293         int err = 0;
 294
 295 #define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)
 296         COPY(regs[0]);  COPY(regs[1]);
 297         COPY(regs[2]);  COPY(regs[3]);
 298         COPY(regs[4]);  COPY(regs[5]);
 299         COPY(regs[6]);  COPY(regs[7]);
 300         COPY(regs[8]);  COPY(regs[9]);
 301         COPY(regs[10]); COPY(regs[11]);
 302         COPY(regs[12]); COPY(regs[13]);
 303         COPY(regs[14]); COPY(regs[15]);
 304         COPY(gbr);      COPY(mach);
 305         COPY(macl);     COPY(pr);
 306         COPY(sr);       COPY(pc);
 307 #undef COPY
 308
 309 #ifdef CONFIG_SH_FPU
 310         err |= save_sigcontext_fpu(sc, regs);
 311 #endif
 312
 313         /* non-iBCS2 extensions.. */
 314         err |= __put_user(mask, &sc->oldmask);
 315
 316         return err;
 317 }
 318
 319 /*
 320  * Determine which stack to use..
 321  */
 322 static inline void __user *
 323 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 324 {
 325         if (ka->sa.sa_flags & SA_ONSTACK) {
 326                 if (sas_ss_flags(sp) == 0)
 327                         sp = current->sas_ss_sp + current->sas_ss_size;
 328         }
 329
 330         return (void __user *)((sp - frame_size) & -8ul);
 331 }
 332
 333 /* These symbols are defined with the addresses in the vsyscall page.
 334    See vsyscall-trapa.S.  */
 335 extern void __user __kernel_sigreturn;
 336 extern void __user __kernel_rt_sigreturn;
 337
 338 static int setup_frame(int sig, struct k_sigaction *ka,
 339                         sigset_t *set, struct pt_regs *regs)
 340 {
 341         struct sigframe __user *frame;
 342         int err = 0;
 343         int signal;
 344
 345         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 346
 347         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 348                 goto give_sigsegv;
 349
 350         signal = current_thread_info()->exec_domain
 351                 && current_thread_info()->exec_domain->signal_invmap
 352                 && sig < 32
 353                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 354                 : sig;
 355
 356         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 357
 358         if (_NSIG_WORDS > 1)
 359                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 360                                       sizeof(frame->extramask));
 361
 362         /* Set up to return from userspace.  If provided, use a stub
 363            already in userspace.  */
 364         if (ka->sa.sa_flags & SA_RESTORER) {
 365                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 366 #ifdef CONFIG_VSYSCALL
 367         } else if (likely(current->mm->context.vdso)) {
 368                 regs->pr = VDSO_SYM(&__kernel_sigreturn);
 369 #endif
 370         } else {
 371                 /* Generate return code (system call to sigreturn) */
 372                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 373                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 374                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 375                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 376                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 377                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 378                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 379                 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
 380                 regs->pr = (unsigned long) frame->retcode;
 381                 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 382         }
 383
 384         if (err)
 385                 goto give_sigsegv;
 386
 387         /* Set up registers for signal handler */
 388         regs->regs[15] = (unsigned long) frame;
 389         regs->regs[4] = signal; /* Arg for signal handler */
 390         regs->regs[5] = 0;
 391         regs->regs[6] = (unsigned long) &frame->sc;
 392
 393         if (current->personality & FDPIC_FUNCPTRS) {
 394                 struct fdpic_func_descriptor __user *funcptr =
 395                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 396
 397                 __get_user(regs->pc, &funcptr->text);
 398                 __get_user(regs->regs[12], &funcptr->GOT);
 399         } else
 400                 regs->pc = (unsigned long)ka->sa.sa_handler;
 401
 402         set_fs(USER_DS);
 403
 404         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 405                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 406
 407         return 0;
 408
 409 give_sigsegv:
 410         force_sigsegv(sig, current);
 411         return -EFAULT;
 412 }
 413
 414 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 415                            sigset_t *set, struct pt_regs *regs)
 416 {
 417         struct rt_sigframe __user *frame;
 418         int err = 0;
 419         int signal;
 420
 421         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 422
 423         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 424                 goto give_sigsegv;
 425
 426         signal = current_thread_info()->exec_domain
 427                 && current_thread_info()->exec_domain->signal_invmap
 428                 && sig < 32
 429                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 430                 : sig;
 431
 432         err |= copy_siginfo_to_user(&frame->info, info);
 433
 434         /* Create the ucontext.  */
 435         err |= __put_user(0, &frame->uc.uc_flags);
 436         err |= __put_user(NULL, &frame->uc.uc_link);
 437         err |= __put_user((void *)current->sas_ss_sp,
 438                           &frame->uc.uc_stack.ss_sp);
 439         err |= __put_user(sas_ss_flags(regs->regs[15]),
 440                           &frame->uc.uc_stack.ss_flags);
 441         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 442         err |= setup_sigcontext(&frame->uc.uc_mcontext,
 443                                 regs, set->sig[0]);
 444         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 445
 446         /* Set up to return from userspace.  If provided, use a stub
 447            already in userspace.  */
 448         if (ka->sa.sa_flags & SA_RESTORER) {
 449                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 450 #ifdef CONFIG_VSYSCALL
 451         } else if (likely(current->mm->context.vdso)) {
 452                 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
 453 #endif
 454         } else {
 455                 /* Generate return code (system call to rt_sigreturn) */
 456                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 457                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 458                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 459                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 460                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 461                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 462                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 463                 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
 464                 regs->pr = (unsigned long) frame->retcode;
 465         }
 466
 467         if (err)
 468                 goto give_sigsegv;
 469
 470         /* Set up registers for signal handler */
 471         regs->regs[15] = (unsigned long) frame;
 472         regs->regs[4] = signal; /* Arg for signal handler */
 473         regs->regs[5] = (unsigned long) &frame->info;
 474         regs->regs[6] = (unsigned long) &frame->uc;
 475
 476         if (current->personality & FDPIC_FUNCPTRS) {
 477                 struct fdpic_func_descriptor __user *funcptr =
 478                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 479
 480                 __get_user(regs->pc, &funcptr->text);
 481                 __get_user(regs->regs[12], &funcptr->GOT);
 482         } else
 483                 regs->pc = (unsigned long)ka->sa.sa_handler;
 484
 485         set_fs(USER_DS);
 486
 487         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 488                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 489
 490         flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 491
 492         return 0;
 493
 494 give_sigsegv:
 495         force_sigsegv(sig, current);
 496         return -EFAULT;
 497 }
 498
 499 static inline void
 500 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
 501                        struct sigaction *sa)
 502 {
 503         /* If we're not from a syscall, bail out */
 504         if (regs->tra < 0)
 505                 return;
 506
 507         /* check for system call restart.. */
 508         switch (regs->regs[0]) {
 509                 case -ERESTART_RESTARTBLOCK:
 510                 case -ERESTARTNOHAND:
 511                 no_system_call_restart:
 512                         regs->regs[0] = -EINTR;
 513                         break;
 514
 515                 case -ERESTARTSYS:
 516                         if (!(sa->sa_flags & SA_RESTART))
 517                                 goto no_system_call_restart;
 518                 /* fallthrough */
 519                 case -ERESTARTNOINTR:
 520                         regs->regs[0] = save_r0;
 521                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 522                         break;
 523         }
 524 }
 525
 526 /*
 527  * OK, we're invoking a handler
 528  */
 529 static int
 530 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 531               sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0)
 532 {
 533         int ret;
 534
 535         /* Set up the stack frame */
 536         if (ka->sa.sa_flags & SA_SIGINFO)
 537                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 538         else
 539                 ret = setup_frame(sig, ka, oldset, regs);
 540
 541         if (ka->sa.sa_flags & SA_ONESHOT)
 542                 ka->sa.sa_handler = SIG_DFL;
 543
 544         if (ret == 0) {
 545                 spin_lock_irq(&current->sighand->siglock);
 546                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 547                 if (!(ka->sa.sa_flags & SA_NODEFER))
 548                         sigaddset(&current->blocked,sig);
 549                 recalc_sigpending();
 550                 spin_unlock_irq(&current->sighand->siglock);
 551         }
 552
 553         return ret;
 554 }
 555
 556 /*
 557  * Note that 'init' is a special process: it doesn't get signals it doesn't
 558  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 559  * mistake.
 560  *
 561  * Note that we go through the signals twice: once to check the signals that
 562  * the kernel can handle, and then we build all the user-level signal handling
 563  * stack-frames in one go after that.
 564  */
 565 static void do_signal(struct pt_regs *regs, unsigned int save_r0)
 566 {
 567         siginfo_t info;
 568         int signr;
 569         struct k_sigaction ka;
 570         sigset_t *oldset;
 571
 572         /*
 573          * We want the common case to go fast, which
 574          * is why we may in certain cases get here from
 575          * kernel mode. Just return without doing anything
 576          * if so.
 577          */
 578         if (!user_mode(regs))
 579                 return;
 580
 581         if (try_to_freeze())
 582                 goto no_signal;
 583
 584         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 585                 oldset = &current->saved_sigmask;
 586         else
 587                 oldset = &current->blocked;
 588
 589         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 590         if (signr > 0) {
 591                 handle_syscall_restart(save_r0, regs, &ka.sa);
 592
 593                 /* Whee!  Actually deliver the signal.  */
 594                 if (handle_signal(signr, &ka, &info, oldset,
 595                                   regs, save_r0) == 0) {
 596                         /* a signal was successfully delivered; the saved
 597                          * sigmask will have been stored in the signal frame,
 598                          * and will be restored by sigreturn, so we can simply
 599                          * clear the TIF_RESTORE_SIGMASK flag */
 600                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 601                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 602
 603                         tracehook_signal_handler(signr, &info, &ka, regs,
 604                                         test_thread_flag(TIF_SINGLESTEP));
 605                 }
 606
 607                 return;
 608         }
 609
 610 no_signal:
 611         /* Did we come from a system call? */
 612         if (regs->tra >= 0) {
 613                 /* Restart the system call - no handlers present */
 614                 if (regs->regs[0] == -ERESTARTNOHAND ||
 615                     regs->regs[0] == -ERESTARTSYS ||
 616                     regs->regs[0] == -ERESTARTNOINTR) {
 617                         regs->regs[0] = save_r0;
 618                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 619                 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
 620                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 621                         regs->regs[3] = __NR_restart_syscall;
 622                 }
 623         }
 624
 625         /* if there's no signal to deliver, we just put the saved sigmask
 626          * back */
 627         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 628                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 629                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 630         }
 631 }
 632
 633 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
 634                                  unsigned long thread_info_flags)
 635 {
 636         /* deal with pending signal delivery */
 637         if (thread_info_flags & _TIF_SIGPENDING)
 638                 do_signal(regs, save_r0);
 639
 640         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 641                 clear_thread_flag(TIF_NOTIFY_RESUME);
 642                 tracehook_notify_resume(regs);
 643         }
 644 }