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  * The following define adds a 64 byte gap between the signal
  45  * stack frame and previous contents of the stack.  This allows
  46  * frame unwinding in a function epilogue but only if a frame
  47  * pointer is used in the function.  This is necessary because
  48  * current gcc compilers (<4.3) do not generate unwind info on
  49  * SH for function epilogues.
  50  */
  51 #define UNWINDGUARD 64
  52
  53 /*
  54  * Atomically swap in the new signal mask, and wait for a signal.
  55  */
  56 asmlinkage int
  57 sys_sigsuspend(old_sigset_t mask,
  58                unsigned long r5, unsigned long r6, unsigned long r7,
  59                struct pt_regs __regs)
  60 {
  61         mask &= _BLOCKABLE;
  62         spin_lock_irq(&current->sighand->siglock);
  63         current->saved_sigmask = current->blocked;
  64         siginitset(&current->blocked, mask);
  65         recalc_sigpending();
  66         spin_unlock_irq(&current->sighand->siglock);
  67
  68         current->state = TASK_INTERRUPTIBLE;
  69         schedule();
  70         set_thread_flag(TIF_RESTORE_SIGMASK);
  71         return -ERESTARTNOHAND;
  72 }
  73
  74 asmlinkage int
  75 sys_sigaction(int sig, const struct old_sigaction __user *act,
  76               struct old_sigaction __user *oact)
  77 {
  78         struct k_sigaction new_ka, old_ka;
  79         int ret;
  80
  81         if (act) {
  82                 old_sigset_t mask;
  83                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  84                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  85                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  86                         return -EFAULT;
  87                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  88                 __get_user(mask, &act->sa_mask);
  89                 siginitset(&new_ka.sa.sa_mask, mask);
  90         }
  91
  92         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  93
  94         if (!ret && oact) {
  95                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  96                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  97                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  98                         return -EFAULT;
  99                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 100                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 101         }
 102
 103         return ret;
 104 }
 105
 106 asmlinkage int
 107 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 108                 unsigned long r6, unsigned long r7,
 109                 struct pt_regs __regs)
 110 {
 111         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 112
 113         return do_sigaltstack(uss, uoss, regs->regs[15]);
 114 }
 115
 116
 117 /*
 118  * Do a signal return; undo the signal stack.
 119  */
 120
 121 #define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */
 122 #if defined(CONFIG_CPU_SH2)
 123 #define TRAP_NOARG 0xc320               /* Syscall w/no args (NR in R3) */
 124 #else
 125 #define TRAP_NOARG 0xc310               /* Syscall w/no args (NR in R3) */
 126 #endif
 127 #define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */
 128
 129 struct sigframe
 130 {
 131         struct sigcontext sc;
 132         unsigned long extramask[_NSIG_WORDS-1];
 133         u16 retcode[8];
 134 };
 135
 136 struct rt_sigframe
 137 {
 138         struct siginfo info;
 139         struct ucontext uc;
 140         u16 retcode[8];
 141 };
 142
 143 #ifdef CONFIG_SH_FPU
 144 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
 145 {
 146         struct task_struct *tsk = current;
 147
 148         if (!(current_cpu_data.flags & CPU_HAS_FPU))
 149                 return 0;
 150
 151         set_used_math();
 152         return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],
 153                                 sizeof(long)*(16*2+2));
 154 }
 155
 156 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
 157                                       struct pt_regs *regs)
 158 {
 159         struct task_struct *tsk = current;
 160
 161         if (!(current_cpu_data.flags & CPU_HAS_FPU))
 162                 return 0;
 163
 164         if (!used_math()) {
 165                 __put_user(0, &sc->sc_ownedfp);
 166                 return 0;
 167         }
 168
 169         __put_user(1, &sc->sc_ownedfp);
 170
 171         /* This will cause a "finit" to be triggered by the next
 172            attempted FPU operation by the 'current' process.
 173            */
 174         clear_used_math();
 175
 176         unlazy_fpu(tsk, regs);
 177         return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,
 178                               sizeof(long)*(16*2+2));
 179 }
 180 #endif /* CONFIG_SH_FPU */
 181
 182 static int
 183 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
 184 {
 185         unsigned int err = 0;
 186
 187 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
 188                         COPY(regs[1]);
 189         COPY(regs[2]);  COPY(regs[3]);
 190         COPY(regs[4]);  COPY(regs[5]);
 191         COPY(regs[6]);  COPY(regs[7]);
 192         COPY(regs[8]);  COPY(regs[9]);
 193         COPY(regs[10]); COPY(regs[11]);
 194         COPY(regs[12]); COPY(regs[13]);
 195         COPY(regs[14]); COPY(regs[15]);
 196         COPY(gbr);      COPY(mach);
 197         COPY(macl);     COPY(pr);
 198         COPY(sr);       COPY(pc);
 199 #undef COPY
 200
 201 #ifdef CONFIG_SH_FPU
 202         if (current_cpu_data.flags & CPU_HAS_FPU) {
 203                 int owned_fp;
 204                 struct task_struct *tsk = current;
 205
 206                 regs->sr |= SR_FD; /* Release FPU */
 207                 clear_fpu(tsk, regs);
 208                 clear_used_math();
 209                 __get_user (owned_fp, &sc->sc_ownedfp);
 210                 if (owned_fp)
 211                         err |= restore_sigcontext_fpu(sc);
 212         }
 213 #endif
 214
 215         regs->tra = -1;         /* disable syscall checks */
 216         err |= __get_user(*r0_p, &sc->sc_regs[0]);
 217         return err;
 218 }
 219
 220 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
 221                              unsigned long r6, unsigned long r7,
 222                              struct pt_regs __regs)
 223 {
 224         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 225         struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
 226         sigset_t set;
 227         int r0;
 228
 229         /* Always make any pending restarted system calls return -EINTR */
 230         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 231
 232         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 233                 goto badframe;
 234
 235         if (__get_user(set.sig[0], &frame->sc.oldmask)
 236             || (_NSIG_WORDS > 1
 237                 && __copy_from_user(&set.sig[1], &frame->extramask,
 238                                     sizeof(frame->extramask))))
 239                 goto badframe;
 240
 241         sigdelsetmask(&set, ~_BLOCKABLE);
 242
 243         spin_lock_irq(&current->sighand->siglock);
 244         current->blocked = set;
 245         recalc_sigpending();
 246         spin_unlock_irq(&current->sighand->siglock);
 247
 248         if (restore_sigcontext(regs, &frame->sc, &r0))
 249                 goto badframe;
 250         return r0;
 251
 252 badframe:
 253         force_sig(SIGSEGV, current);
 254         return 0;
 255 }
 256
 257 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
 258                                 unsigned long r6, unsigned long r7,
 259                                 struct pt_regs __regs)
 260 {
 261         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 262         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
 263         sigset_t set;
 264         int r0;
 265
 266         /* Always make any pending restarted system calls return -EINTR */
 267         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 268
 269         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 270                 goto badframe;
 271
 272         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 273                 goto badframe;
 274
 275         sigdelsetmask(&set, ~_BLOCKABLE);
 276         spin_lock_irq(&current->sighand->siglock);
 277         current->blocked = set;
 278         recalc_sigpending();
 279         spin_unlock_irq(&current->sighand->siglock);
 280
 281         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 282                 goto badframe;
 283
 284         if (do_sigaltstack(&frame->uc.uc_stack, NULL,
 285                            regs->regs[15]) == -EFAULT)
 286                 goto badframe;
 287
 288         return r0;
 289
 290 badframe:
 291         force_sig(SIGSEGV, current);
 292         return 0;
 293 }
 294
 295 /*
 296  * Set up a signal frame.
 297  */
 298
 299 static int
 300 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 301                  unsigned long mask)
 302 {
 303         int err = 0;
 304
 305 #define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)
 306         COPY(regs[0]);  COPY(regs[1]);
 307         COPY(regs[2]);  COPY(regs[3]);
 308         COPY(regs[4]);  COPY(regs[5]);
 309         COPY(regs[6]);  COPY(regs[7]);
 310         COPY(regs[8]);  COPY(regs[9]);
 311         COPY(regs[10]); COPY(regs[11]);
 312         COPY(regs[12]); COPY(regs[13]);
 313         COPY(regs[14]); COPY(regs[15]);
 314         COPY(gbr);      COPY(mach);
 315         COPY(macl);     COPY(pr);
 316         COPY(sr);       COPY(pc);
 317 #undef COPY
 318
 319 #ifdef CONFIG_SH_FPU
 320         err |= save_sigcontext_fpu(sc, regs);
 321 #endif
 322
 323         /* non-iBCS2 extensions.. */
 324         err |= __put_user(mask, &sc->oldmask);
 325
 326         return err;
 327 }
 328
 329 /*
 330  * Determine which stack to use..
 331  */
 332 static inline void __user *
 333 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 334 {
 335         if (ka->sa.sa_flags & SA_ONSTACK) {
 336                 if (sas_ss_flags(sp) == 0)
 337                         sp = current->sas_ss_sp + current->sas_ss_size;
 338         }
 339
 340         return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul);
 341 }
 342
 343 /* These symbols are defined with the addresses in the vsyscall page.
 344    See vsyscall-trapa.S.  */
 345 extern void __kernel_sigreturn(void);
 346 extern void __kernel_rt_sigreturn(void);
 347
 348 static int setup_frame(int sig, struct k_sigaction *ka,
 349                         sigset_t *set, struct pt_regs *regs)
 350 {
 351         struct sigframe __user *frame;
 352         int err = 0;
 353         int signal;
 354
 355         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 356
 357         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 358                 goto give_sigsegv;
 359
 360         signal = current_thread_info()->exec_domain
 361                 && current_thread_info()->exec_domain->signal_invmap
 362                 && sig < 32
 363                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 364                 : sig;
 365
 366         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 367
 368         if (_NSIG_WORDS > 1)
 369                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 370                                       sizeof(frame->extramask));
 371
 372         /* Set up to return from userspace.  If provided, use a stub
 373            already in userspace.  */
 374         if (ka->sa.sa_flags & SA_RESTORER) {
 375                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 376 #ifdef CONFIG_VSYSCALL
 377         } else if (likely(current->mm->context.vdso)) {
 378                 regs->pr = VDSO_SYM(&__kernel_sigreturn);
 379 #endif
 380         } else {
 381                 /* Generate return code (system call to sigreturn) */
 382                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 383                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 384                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 385                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 386                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 387                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 388                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 389                 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
 390                 regs->pr = (unsigned long) frame->retcode;
 391                 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 392         }
 393
 394         if (err)
 395                 goto give_sigsegv;
 396
 397         /* Set up registers for signal handler */
 398         regs->regs[15] = (unsigned long) frame;
 399         regs->regs[4] = signal; /* Arg for signal handler */
 400         regs->regs[5] = 0;
 401         regs->regs[6] = (unsigned long) &frame->sc;
 402
 403         if (current->personality & FDPIC_FUNCPTRS) {
 404                 struct fdpic_func_descriptor __user *funcptr =
 405                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 406
 407                 __get_user(regs->pc, &funcptr->text);
 408                 __get_user(regs->regs[12], &funcptr->GOT);
 409         } else
 410                 regs->pc = (unsigned long)ka->sa.sa_handler;
 411
 412         set_fs(USER_DS);
 413
 414         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 415                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 416
 417         return 0;
 418
 419 give_sigsegv:
 420         force_sigsegv(sig, current);
 421         return -EFAULT;
 422 }
 423
 424 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 425                            sigset_t *set, struct pt_regs *regs)
 426 {
 427         struct rt_sigframe __user *frame;
 428         int err = 0;
 429         int signal;
 430
 431         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 432
 433         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 434                 goto give_sigsegv;
 435
 436         signal = current_thread_info()->exec_domain
 437                 && current_thread_info()->exec_domain->signal_invmap
 438                 && sig < 32
 439                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 440                 : sig;
 441
 442         err |= copy_siginfo_to_user(&frame->info, info);
 443
 444         /* Create the ucontext.  */
 445         err |= __put_user(0, &frame->uc.uc_flags);
 446         err |= __put_user(NULL, &frame->uc.uc_link);
 447         err |= __put_user((void *)current->sas_ss_sp,
 448                           &frame->uc.uc_stack.ss_sp);
 449         err |= __put_user(sas_ss_flags(regs->regs[15]),
 450                           &frame->uc.uc_stack.ss_flags);
 451         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 452         err |= setup_sigcontext(&frame->uc.uc_mcontext,
 453                                 regs, set->sig[0]);
 454         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 455
 456         /* Set up to return from userspace.  If provided, use a stub
 457            already in userspace.  */
 458         if (ka->sa.sa_flags & SA_RESTORER) {
 459                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 460 #ifdef CONFIG_VSYSCALL
 461         } else if (likely(current->mm->context.vdso)) {
 462                 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
 463 #endif
 464         } else {
 465                 /* Generate return code (system call to rt_sigreturn) */
 466                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 467                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 468                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 469                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 470                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 471                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 472                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 473                 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
 474                 regs->pr = (unsigned long) frame->retcode;
 475         }
 476
 477         if (err)
 478                 goto give_sigsegv;
 479
 480         /* Set up registers for signal handler */
 481         regs->regs[15] = (unsigned long) frame;
 482         regs->regs[4] = signal; /* Arg for signal handler */
 483         regs->regs[5] = (unsigned long) &frame->info;
 484         regs->regs[6] = (unsigned long) &frame->uc;
 485
 486         if (current->personality & FDPIC_FUNCPTRS) {
 487                 struct fdpic_func_descriptor __user *funcptr =
 488                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 489
 490                 __get_user(regs->pc, &funcptr->text);
 491                 __get_user(regs->regs[12], &funcptr->GOT);
 492         } else
 493                 regs->pc = (unsigned long)ka->sa.sa_handler;
 494
 495         set_fs(USER_DS);
 496
 497         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 498                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 499
 500         flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 501
 502         return 0;
 503
 504 give_sigsegv:
 505         force_sigsegv(sig, current);
 506         return -EFAULT;
 507 }
 508
 509 static inline void
 510 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
 511                        struct sigaction *sa)
 512 {
 513         /* If we're not from a syscall, bail out */
 514         if (regs->tra < 0)
 515                 return;
 516
 517         /* check for system call restart.. */
 518         switch (regs->regs[0]) {
 519                 case -ERESTART_RESTARTBLOCK:
 520                 case -ERESTARTNOHAND:
 521                 no_system_call_restart:
 522                         regs->regs[0] = -EINTR;
 523                         break;
 524
 525                 case -ERESTARTSYS:
 526                         if (!(sa->sa_flags & SA_RESTART))
 527                                 goto no_system_call_restart;
 528                 /* fallthrough */
 529                 case -ERESTARTNOINTR:
 530                         regs->regs[0] = save_r0;
 531                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 532                         break;
 533         }
 534 }
 535
 536 /*
 537  * OK, we're invoking a handler
 538  */
 539 static int
 540 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 541               sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0)
 542 {
 543         int ret;
 544
 545         /* Set up the stack frame */
 546         if (ka->sa.sa_flags & SA_SIGINFO)
 547                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 548         else
 549                 ret = setup_frame(sig, ka, oldset, regs);
 550
 551         if (ka->sa.sa_flags & SA_ONESHOT)
 552                 ka->sa.sa_handler = SIG_DFL;
 553
 554         if (ret == 0) {
 555                 spin_lock_irq(&current->sighand->siglock);
 556                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 557                 if (!(ka->sa.sa_flags & SA_NODEFER))
 558                         sigaddset(&current->blocked,sig);
 559                 recalc_sigpending();
 560                 spin_unlock_irq(&current->sighand->siglock);
 561         }
 562
 563         return ret;
 564 }
 565
 566 /*
 567  * Note that 'init' is a special process: it doesn't get signals it doesn't
 568  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 569  * mistake.
 570  *
 571  * Note that we go through the signals twice: once to check the signals that
 572  * the kernel can handle, and then we build all the user-level signal handling
 573  * stack-frames in one go after that.
 574  */
 575 static void do_signal(struct pt_regs *regs, unsigned int save_r0)
 576 {
 577         siginfo_t info;
 578         int signr;
 579         struct k_sigaction ka;
 580         sigset_t *oldset;
 581
 582         /*
 583          * We want the common case to go fast, which
 584          * is why we may in certain cases get here from
 585          * kernel mode. Just return without doing anything
 586          * if so.
 587          */
 588         if (!user_mode(regs))
 589                 return;
 590
 591         if (try_to_freeze())
 592                 goto no_signal;
 593
 594         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 595                 oldset = &current->saved_sigmask;
 596         else
 597                 oldset = &current->blocked;
 598
 599         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 600         if (signr > 0) {
 601                 handle_syscall_restart(save_r0, regs, &ka.sa);
 602
 603                 /* Whee!  Actually deliver the signal.  */
 604                 if (handle_signal(signr, &ka, &info, oldset,
 605                                   regs, save_r0) == 0) {
 606                         /* a signal was successfully delivered; the saved
 607                          * sigmask will have been stored in the signal frame,
 608                          * and will be restored by sigreturn, so we can simply
 609                          * clear the TIF_RESTORE_SIGMASK flag */
 610                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 611                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 612
 613                         tracehook_signal_handler(signr, &info, &ka, regs,
 614                                         test_thread_flag(TIF_SINGLESTEP));
 615                 }
 616
 617                 return;
 618         }
 619
 620 no_signal:
 621         /* Did we come from a system call? */
 622         if (regs->tra >= 0) {
 623                 /* Restart the system call - no handlers present */
 624                 if (regs->regs[0] == -ERESTARTNOHAND ||
 625                     regs->regs[0] == -ERESTARTSYS ||
 626                     regs->regs[0] == -ERESTARTNOINTR) {
 627                         regs->regs[0] = save_r0;
 628                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 629                 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
 630                         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
 631                         regs->regs[3] = __NR_restart_syscall;
 632                 }
 633         }
 634
 635         /* if there's no signal to deliver, we just put the saved sigmask
 636          * back */
 637         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 638                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 639                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 640         }
 641 }
 642
 643 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
 644                                  unsigned long thread_info_flags)
 645 {
 646         /* deal with pending signal delivery */
 647         if (thread_info_flags & _TIF_SIGPENDING)
 648                 do_signal(regs, save_r0);
 649
 650         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 651                 clear_thread_flag(TIF_NOTIFY_RESUME);
 652                 tracehook_notify_resume(regs);
 653                 if (current->replacement_session_keyring)
 654                         key_replace_session_keyring();
 655         }
 656 }