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_restore_sigmask();
  71
  72         return -ERESTARTNOHAND;
  73 }
  74
  75 asmlinkage int
  76 sys_sigaction(int sig, const struct old_sigaction __user *act,
  77               struct old_sigaction __user *oact)
  78 {
  79         struct k_sigaction new_ka, old_ka;
  80         int ret;
  81
  82         if (act) {
  83                 old_sigset_t mask;
  84                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  85                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  86                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  87                         return -EFAULT;
  88                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  89                 __get_user(mask, &act->sa_mask);
  90                 siginitset(&new_ka.sa.sa_mask, mask);
  91         }
  92
  93         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  94
  95         if (!ret && oact) {
  96                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  97                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  98                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  99                         return -EFAULT;
 100                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 101                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 102         }
 103
 104         return ret;
 105 }
 106
 107 asmlinkage int
 108 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 109                 unsigned long r6, unsigned long r7,
 110                 struct pt_regs __regs)
 111 {
 112         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 113
 114         return do_sigaltstack(uss, uoss, regs->regs[15]);
 115 }
 116
 117
 118 /*
 119  * Do a signal return; undo the signal stack.
 120  */
 121
 122 #define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */
 123 #if defined(CONFIG_CPU_SH2)
 124 #define TRAP_NOARG 0xc320               /* Syscall w/no args (NR in R3) */
 125 #else
 126 #define TRAP_NOARG 0xc310               /* Syscall w/no args (NR in R3) */
 127 #endif
 128 #define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */
 129
 130 struct sigframe
 131 {
 132         struct sigcontext sc;
 133         unsigned long extramask[_NSIG_WORDS-1];
 134         u16 retcode[8];
 135 };
 136
 137 struct rt_sigframe
 138 {
 139         struct siginfo info;
 140         struct ucontext uc;
 141         u16 retcode[8];
 142 };
 143
 144 #ifdef CONFIG_SH_FPU
 145 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
 146 {
 147         struct task_struct *tsk = current;
 148
 149         if (!(boot_cpu_data.flags & CPU_HAS_FPU))
 150                 return 0;
 151
 152         set_used_math();
 153         return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0],
 154                                 sizeof(long)*(16*2+2));
 155 }
 156
 157 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
 158                                       struct pt_regs *regs)
 159 {
 160         struct task_struct *tsk = current;
 161
 162         if (!(boot_cpu_data.flags & CPU_HAS_FPU))
 163                 return 0;
 164
 165         if (!used_math()) {
 166                 __put_user(0, &sc->sc_ownedfp);
 167                 return 0;
 168         }
 169
 170         __put_user(1, &sc->sc_ownedfp);
 171
 172         /* This will cause a "finit" to be triggered by the next
 173            attempted FPU operation by the 'current' process.
 174            */
 175         clear_used_math();
 176
 177         unlazy_fpu(tsk, regs);
 178         return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu,
 179                               sizeof(long)*(16*2+2));
 180 }
 181 #endif /* CONFIG_SH_FPU */
 182
 183 static int
 184 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
 185 {
 186         unsigned int err = 0;
 187
 188 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
 189                         COPY(regs[1]);
 190         COPY(regs[2]);  COPY(regs[3]);
 191         COPY(regs[4]);  COPY(regs[5]);
 192         COPY(regs[6]);  COPY(regs[7]);
 193         COPY(regs[8]);  COPY(regs[9]);
 194         COPY(regs[10]); COPY(regs[11]);
 195         COPY(regs[12]); COPY(regs[13]);
 196         COPY(regs[14]); COPY(regs[15]);
 197         COPY(gbr);      COPY(mach);
 198         COPY(macl);     COPY(pr);
 199         COPY(sr);       COPY(pc);
 200 #undef COPY
 201
 202 #ifdef CONFIG_SH_FPU
 203         if (boot_cpu_data.flags & CPU_HAS_FPU) {
 204                 int owned_fp;
 205                 struct task_struct *tsk = current;
 206
 207                 regs->sr |= SR_FD; /* Release FPU */
 208                 clear_fpu(tsk, regs);
 209                 clear_used_math();
 210                 __get_user (owned_fp, &sc->sc_ownedfp);
 211                 if (owned_fp)
 212                         err |= restore_sigcontext_fpu(sc);
 213         }
 214 #endif
 215
 216         regs->tra = -1;         /* disable syscall checks */
 217         err |= __get_user(*r0_p, &sc->sc_regs[0]);
 218         return err;
 219 }
 220
 221 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
 222                              unsigned long r6, unsigned long r7,
 223                              struct pt_regs __regs)
 224 {
 225         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 226         struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
 227         sigset_t set;
 228         int r0;
 229
 230         /* Always make any pending restarted system calls return -EINTR */
 231         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 232
 233         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 234                 goto badframe;
 235
 236         if (__get_user(set.sig[0], &frame->sc.oldmask)
 237             || (_NSIG_WORDS > 1
 238                 && __copy_from_user(&set.sig[1], &frame->extramask,
 239                                     sizeof(frame->extramask))))
 240                 goto badframe;
 241
 242         sigdelsetmask(&set, ~_BLOCKABLE);
 243
 244         spin_lock_irq(&current->sighand->siglock);
 245         current->blocked = set;
 246         recalc_sigpending();
 247         spin_unlock_irq(&current->sighand->siglock);
 248
 249         if (restore_sigcontext(regs, &frame->sc, &r0))
 250                 goto badframe;
 251         return r0;
 252
 253 badframe:
 254         force_sig(SIGSEGV, current);
 255         return 0;
 256 }
 257
 258 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
 259                                 unsigned long r6, unsigned long r7,
 260                                 struct pt_regs __regs)
 261 {
 262         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 263         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
 264         sigset_t set;
 265         int r0;
 266
 267         /* Always make any pending restarted system calls return -EINTR */
 268         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 269
 270         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 271                 goto badframe;
 272
 273         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 274                 goto badframe;
 275
 276         sigdelsetmask(&set, ~_BLOCKABLE);
 277         spin_lock_irq(&current->sighand->siglock);
 278         current->blocked = set;
 279         recalc_sigpending();
 280         spin_unlock_irq(&current->sighand->siglock);
 281
 282         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 283                 goto badframe;
 284
 285         if (do_sigaltstack(&frame->uc.uc_stack, NULL,
 286                            regs->regs[15]) == -EFAULT)
 287                 goto badframe;
 288
 289         return r0;
 290
 291 badframe:
 292         force_sig(SIGSEGV, current);
 293         return 0;
 294 }
 295
 296 /*
 297  * Set up a signal frame.
 298  */
 299
 300 static int
 301 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 302                  unsigned long mask)
 303 {
 304         int err = 0;
 305
 306 #define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)
 307         COPY(regs[0]);  COPY(regs[1]);
 308         COPY(regs[2]);  COPY(regs[3]);
 309         COPY(regs[4]);  COPY(regs[5]);
 310         COPY(regs[6]);  COPY(regs[7]);
 311         COPY(regs[8]);  COPY(regs[9]);
 312         COPY(regs[10]); COPY(regs[11]);
 313         COPY(regs[12]); COPY(regs[13]);
 314         COPY(regs[14]); COPY(regs[15]);
 315         COPY(gbr);      COPY(mach);
 316         COPY(macl);     COPY(pr);
 317         COPY(sr);       COPY(pc);
 318 #undef COPY
 319
 320 #ifdef CONFIG_SH_FPU
 321         err |= save_sigcontext_fpu(sc, regs);
 322 #endif
 323
 324         /* non-iBCS2 extensions.. */
 325         err |= __put_user(mask, &sc->oldmask);
 326
 327         return err;
 328 }
 329
 330 /*
 331  * Determine which stack to use..
 332  */
 333 static inline void __user *
 334 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 335 {
 336         if (ka->sa.sa_flags & SA_ONSTACK) {
 337                 if (sas_ss_flags(sp) == 0)
 338                         sp = current->sas_ss_sp + current->sas_ss_size;
 339         }
 340
 341         return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul);
 342 }
 343
 344 /* These symbols are defined with the addresses in the vsyscall page.
 345    See vsyscall-trapa.S.  */
 346 extern void __kernel_sigreturn(void);
 347 extern void __kernel_rt_sigreturn(void);
 348
 349 static int setup_frame(int sig, struct k_sigaction *ka,
 350                         sigset_t *set, struct pt_regs *regs)
 351 {
 352         struct sigframe __user *frame;
 353         int err = 0;
 354         int signal;
 355
 356         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 357
 358         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 359                 goto give_sigsegv;
 360
 361         signal = current_thread_info()->exec_domain
 362                 && current_thread_info()->exec_domain->signal_invmap
 363                 && sig < 32
 364                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 365                 : sig;
 366
 367         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 368
 369         if (_NSIG_WORDS > 1)
 370                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 371                                       sizeof(frame->extramask));
 372
 373         /* Set up to return from userspace.  If provided, use a stub
 374            already in userspace.  */
 375         if (ka->sa.sa_flags & SA_RESTORER) {
 376                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 377 #ifdef CONFIG_VSYSCALL
 378         } else if (likely(current->mm->context.vdso)) {
 379                 regs->pr = VDSO_SYM(&__kernel_sigreturn);
 380 #endif
 381         } else {
 382                 /* Generate return code (system call to sigreturn) */
 383                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 384                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 385                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 386                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 387                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 388                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 389                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 390                 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
 391                 regs->pr = (unsigned long) frame->retcode;
 392                 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 393         }
 394
 395         if (err)
 396                 goto give_sigsegv;
 397
 398         /* Set up registers for signal handler */
 399         regs->regs[15] = (unsigned long) frame;
 400         regs->regs[4] = signal; /* Arg for signal handler */
 401         regs->regs[5] = 0;
 402         regs->regs[6] = (unsigned long) &frame->sc;
 403
 404         if (current->personality & FDPIC_FUNCPTRS) {
 405                 struct fdpic_func_descriptor __user *funcptr =
 406                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 407
 408                 __get_user(regs->pc, &funcptr->text);
 409                 __get_user(regs->regs[12], &funcptr->GOT);
 410         } else
 411                 regs->pc = (unsigned long)ka->sa.sa_handler;
 412
 413         set_fs(USER_DS);
 414
 415         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 416                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 417
 418         return 0;
 419
 420 give_sigsegv:
 421         force_sigsegv(sig, current);
 422         return -EFAULT;
 423 }
 424
 425 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 426                            sigset_t *set, struct pt_regs *regs)
 427 {
 428         struct rt_sigframe __user *frame;
 429         int err = 0;
 430         int signal;
 431
 432         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 433
 434         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 435                 goto give_sigsegv;
 436
 437         signal = current_thread_info()->exec_domain
 438                 && current_thread_info()->exec_domain->signal_invmap
 439                 && sig < 32
 440                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 441                 : sig;
 442
 443         err |= copy_siginfo_to_user(&frame->info, info);
 444
 445         /* Create the ucontext.  */
 446         err |= __put_user(0, &frame->uc.uc_flags);
 447         err |= __put_user(NULL, &frame->uc.uc_link);
 448         err |= __put_user((void *)current->sas_ss_sp,
 449                           &frame->uc.uc_stack.ss_sp);
 450         err |= __put_user(sas_ss_flags(regs->regs[15]),
 451                           &frame->uc.uc_stack.ss_flags);
 452         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 453         err |= setup_sigcontext(&frame->uc.uc_mcontext,
 454                                 regs, set->sig[0]);
 455         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 456
 457         /* Set up to return from userspace.  If provided, use a stub
 458            already in userspace.  */
 459         if (ka->sa.sa_flags & SA_RESTORER) {
 460                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 461 #ifdef CONFIG_VSYSCALL
 462         } else if (likely(current->mm->context.vdso)) {
 463                 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
 464 #endif
 465         } else {
 466                 /* Generate return code (system call to rt_sigreturn) */
 467                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 468                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 469                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 470                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 471                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 472                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 473                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 474                 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
 475                 regs->pr = (unsigned long) frame->retcode;
 476                 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 477         }
 478
 479         if (err)
 480                 goto give_sigsegv;
 481
 482         /* Set up registers for signal handler */
 483         regs->regs[15] = (unsigned long) frame;
 484         regs->regs[4] = signal; /* Arg for signal handler */
 485         regs->regs[5] = (unsigned long) &frame->info;
 486         regs->regs[6] = (unsigned long) &frame->uc;
 487
 488         if (current->personality & FDPIC_FUNCPTRS) {
 489                 struct fdpic_func_descriptor __user *funcptr =
 490                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 491
 492                 __get_user(regs->pc, &funcptr->text);
 493                 __get_user(regs->regs[12], &funcptr->GOT);
 494         } else
 495                 regs->pc = (unsigned long)ka->sa.sa_handler;
 496
 497         set_fs(USER_DS);
 498
 499         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 500                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 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(__raw_readw(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 (current_thread_info()->status & TS_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                         /*
 607                          * A signal was successfully delivered; the saved
 608                          * sigmask will have been stored in the signal frame,
 609                          * and will be restored by sigreturn, so we can simply
 610                          * clear the TS_RESTORE_SIGMASK flag
 611                          */
 612                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 613
 614                         tracehook_signal_handler(signr, &info, &ka, regs,
 615                                         test_thread_flag(TIF_SINGLESTEP));
 616                 }
 617
 618                 return;
 619         }
 620
 621 no_signal:
 622         /* Did we come from a system call? */
 623         if (regs->tra >= 0) {
 624                 /* Restart the system call - no handlers present */
 625                 if (regs->regs[0] == -ERESTARTNOHAND ||
 626                     regs->regs[0] == -ERESTARTSYS ||
 627                     regs->regs[0] == -ERESTARTNOINTR) {
 628                         regs->regs[0] = save_r0;
 629                         regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
 630                 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
 631                         regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
 632                         regs->regs[3] = __NR_restart_syscall;
 633                 }
 634         }
 635
 636         /*
 637          * If there's no signal to deliver, we just put the saved sigmask
 638          * back.
 639          */
 640         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 641                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 642                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 643         }
 644 }
 645
 646 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
 647                                  unsigned long thread_info_flags)
 648 {
 649         /* deal with pending signal delivery */
 650         if (thread_info_flags & _TIF_SIGPENDING)
 651                 do_signal(regs, save_r0);
 652
 653         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 654                 clear_thread_flag(TIF_NOTIFY_RESUME);
 655                 tracehook_notify_resume(regs);
 656                 if (current->replacement_session_keyring)
 657                         key_replace_session_keyring();
 658         }
 659 }