LXR linux/arch/i386/kernel/signal.c

   1/*
   2 *  linux/arch/i386/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 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
   8 */
   9
  10#include <linux/sched.h>
  11#include <linux/mm.h>
  12#include <linux/smp.h>
  13#include <linux/kernel.h>
  14#include <linux/signal.h>
  15#include <linux/errno.h>
  16#include <linux/wait.h>
  17#include <linux/unistd.h>
  18#include <linux/stddef.h>
  19#include <linux/personality.h>
  20#include <linux/suspend.h>
  21#include <linux/ptrace.h>
  22#include <linux/elf.h>
  23#include <linux/binfmts.h>
  24#include <asm/processor.h>
  25#include <asm/ucontext.h>
  26#include <asm/uaccess.h>
  27#include <asm/i387.h>
  28#include "sigframe.h"
  29
  30#define DEBUG_SIG 0
  31
  32#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  33
  34/*
  35 * Atomically swap in the new signal mask, and wait for a signal.
  36 */
  37asmlinkage int
  38sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  39{
  40        mask &= _BLOCKABLE;
  41        spin_lock_irq(&current->sighand->siglock);
  42        current->saved_sigmask = current->blocked;
  43        siginitset(&current->blocked, mask);
  44        recalc_sigpending();
  45        spin_unlock_irq(&current->sighand->siglock);
  46
  47        current->state = TASK_INTERRUPTIBLE;
  48        schedule();
  49        set_thread_flag(TIF_RESTORE_SIGMASK);
  50        return -ERESTARTNOHAND;
  51}
  52
  53asmlinkage int 
  54sys_sigaction(int sig, const struct old_sigaction __user *act,
  55              struct old_sigaction __user *oact)
  56{
  57        struct k_sigaction new_ka, old_ka;
  58        int ret;
  59
  60        if (act) {
  61                old_sigset_t mask;
  62                if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  63                    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  64                    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  65                        return -EFAULT;
  66                __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  67                __get_user(mask, &act->sa_mask);
  68                siginitset(&new_ka.sa.sa_mask, mask);
  69        }
  70
  71        ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  72
  73        if (!ret && oact) {
  74                if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  75                    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  76                    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  77                        return -EFAULT;
  78                __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  79                __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  80        }
  81
  82        return ret;
  83}
  84
  85asmlinkage int
  86sys_sigaltstack(unsigned long ebx)
  87{
  88        /* This is needed to make gcc realize it doesn't own the "struct pt_regs" */
  89        struct pt_regs *regs = (struct pt_regs *)&ebx;
  90        const stack_t __user *uss = (const stack_t __user *)ebx;
  91        stack_t __user *uoss = (stack_t __user *)regs->ecx;
  92
  93        return do_sigaltstack(uss, uoss, regs->esp);
  94}
  95
  96
  97/*
  98 * Do a signal return; undo the signal stack.
  99 */
 100
 101static int
 102restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *peax)
 103{
 104        unsigned int err = 0;
 105
 106        /* Always make any pending restarted system calls return -EINTR */
 107        current_thread_info()->restart_block.fn = do_no_restart_syscall;
 108
 109#define COPY(x)         err |= __get_user(regs->x, &sc->x)
 110
 111#define COPY_SEG(seg)                                                   \
 112        { unsigned short tmp;                                           \
 113          err |= __get_user(tmp, &sc->seg);                             \
 114          regs->x##seg = tmp; }
 115
 116#define COPY_SEG_STRICT(seg)                                            \
 117        { unsigned short tmp;                                           \
 118          err |= __get_user(tmp, &sc->seg);                             \
 119          regs->x##seg = tmp|3; }
 120
 121#define GET_SEG(seg)                                                    \
 122        { unsigned short tmp;                                           \
 123          err |= __get_user(tmp, &sc->seg);                             \
 124          loadsegment(seg,tmp); }
 125
 126#define FIX_EFLAGS      (X86_EFLAGS_AC | X86_EFLAGS_RF |                 \
 127                         X86_EFLAGS_OF | X86_EFLAGS_DF |                 \
 128                         X86_EFLAGS_TF | X86_EFLAGS_SF | X86_EFLAGS_ZF | \
 129                         X86_EFLAGS_AF | X86_EFLAGS_PF | X86_EFLAGS_CF)
 130
 131        GET_SEG(gs);
 132        COPY_SEG(fs);
 133        COPY_SEG(es);
 134        COPY_SEG(ds);
 135        COPY(edi);
 136        COPY(esi);
 137        COPY(ebp);
 138        COPY(esp);
 139        COPY(ebx);
 140        COPY(edx);
 141        COPY(ecx);
 142        COPY(eip);
 143        COPY_SEG_STRICT(cs);
 144        COPY_SEG_STRICT(ss);
 145        
 146        {
 147                unsigned int tmpflags;
 148                err |= __get_user(tmpflags, &sc->eflags);
 149                regs->eflags = (regs->eflags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 150                regs->orig_eax = -1;            /* disable syscall checks */
 151        }
 152
 153        {
 154                struct _fpstate __user * buf;
 155                err |= __get_user(buf, &sc->fpstate);
 156                if (buf) {
 157                        if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
 158                                goto badframe;
 159                        err |= restore_i387(buf);
 160                } else {
 161                        struct task_struct *me = current;
 162                        if (used_math()) {
 163                                clear_fpu(me);
 164                                clear_used_math();
 165                        }
 166                }
 167        }
 168
 169        err |= __get_user(*peax, &sc->eax);
 170        return err;
 171
 172badframe:
 173        return 1;
 174}
 175
 176asmlinkage int sys_sigreturn(unsigned long __unused)
 177{
 178        struct pt_regs *regs = (struct pt_regs *) &__unused;
 179        struct sigframe __user *frame = (struct sigframe __user *)(regs->esp - 8);
 180        sigset_t set;
 181        int eax;
 182
 183        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 184                goto badframe;
 185        if (__get_user(set.sig[0], &frame->sc.oldmask)
 186            || (_NSIG_WORDS > 1
 187                && __copy_from_user(&set.sig[1], &frame->extramask,
 188                                    sizeof(frame->extramask))))
 189                goto badframe;
 190
 191        sigdelsetmask(&set, ~_BLOCKABLE);
 192        spin_lock_irq(&current->sighand->siglock);
 193        current->blocked = set;
 194        recalc_sigpending();
 195        spin_unlock_irq(&current->sighand->siglock);
 196        
 197        if (restore_sigcontext(regs, &frame->sc, &eax))
 198                goto badframe;
 199        return eax;
 200
 201badframe:
 202        force_sig(SIGSEGV, current);
 203        return 0;
 204}       
 205
 206asmlinkage int sys_rt_sigreturn(unsigned long __unused)
 207{
 208        struct pt_regs *regs = (struct pt_regs *) &__unused;
 209        struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(regs->esp - 4);
 210        sigset_t set;
 211        int eax;
 212
 213        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 214                goto badframe;
 215        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 216                goto badframe;
 217
 218        sigdelsetmask(&set, ~_BLOCKABLE);
 219        spin_lock_irq(&current->sighand->siglock);
 220        current->blocked = set;
 221        recalc_sigpending();
 222        spin_unlock_irq(&current->sighand->siglock);
 223        
 224        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
 225                goto badframe;
 226
 227        if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->esp) == -EFAULT)
 228                goto badframe;
 229
 230        return eax;
 231
 232badframe:
 233        force_sig(SIGSEGV, current);
 234        return 0;
 235}       
 236
 237/*
 238 * Set up a signal frame.
 239 */
 240
 241static int
 242setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
 243                 struct pt_regs *regs, unsigned long mask)
 244{
 245        int tmp, err = 0;
 246
 247        err |= __put_user(regs->xfs, (unsigned int __user *)&sc->fs);
 248        savesegment(gs, tmp);
 249        err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
 250
 251        err |= __put_user(regs->xes, (unsigned int __user *)&sc->es);
 252        err |= __put_user(regs->xds, (unsigned int __user *)&sc->ds);
 253        err |= __put_user(regs->edi, &sc->edi);
 254        err |= __put_user(regs->esi, &sc->esi);
 255        err |= __put_user(regs->ebp, &sc->ebp);
 256        err |= __put_user(regs->esp, &sc->esp);
 257        err |= __put_user(regs->ebx, &sc->ebx);
 258        err |= __put_user(regs->edx, &sc->edx);
 259        err |= __put_user(regs->ecx, &sc->ecx);
 260        err |= __put_user(regs->eax, &sc->eax);
 261        err |= __put_user(current->thread.trap_no, &sc->trapno);
 262        err |= __put_user(current->thread.error_code, &sc->err);
 263        err |= __put_user(regs->eip, &sc->eip);
 264        err |= __put_user(regs->xcs, (unsigned int __user *)&sc->cs);
 265        err |= __put_user(regs->eflags, &sc->eflags);
 266        err |= __put_user(regs->esp, &sc->esp_at_signal);
 267        err |= __put_user(regs->xss, (unsigned int __user *)&sc->ss);
 268
 269        tmp = save_i387(fpstate);
 270        if (tmp < 0)
 271          err = 1;
 272        else
 273          err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
 274
 275        /* non-iBCS2 extensions.. */
 276        err |= __put_user(mask, &sc->oldmask);
 277        err |= __put_user(current->thread.cr2, &sc->cr2);
 278
 279        return err;
 280}
 281
 282/*
 283 * Determine which stack to use..
 284 */
 285static inline void __user *
 286get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 287{
 288        unsigned long esp;
 289
 290        /* Default to using normal stack */
 291        esp = regs->esp;
 292
 293        /* This is the X/Open sanctioned signal stack switching.  */
 294        if (ka->sa.sa_flags & SA_ONSTACK) {
 295                if (sas_ss_flags(esp) == 0)
 296                        esp = current->sas_ss_sp + current->sas_ss_size;
 297        }
 298
 299        /* This is the legacy signal stack switching. */
 300        else if ((regs->xss & 0xffff) != __USER_DS &&
 301                 !(ka->sa.sa_flags & SA_RESTORER) &&
 302                 ka->sa.sa_restorer) {
 303                esp = (unsigned long) ka->sa.sa_restorer;
 304        }
 305
 306        esp -= frame_size;
 307        /* Align the stack pointer according to the i386 ABI,
 308         * i.e. so that on function entry ((sp + 4) & 15) == 0. */
 309        esp = ((esp + 4) & -16ul) - 4;
 310        return (void __user *) esp;
 311}
 312
 313/* These symbols are defined with the addresses in the vsyscall page.
 314   See vsyscall-sigreturn.S.  */
 315extern void __user __kernel_sigreturn;
 316extern void __user __kernel_rt_sigreturn;
 317
 318static int setup_frame(int sig, struct k_sigaction *ka,
 319                       sigset_t *set, struct pt_regs * regs)
 320{
 321        void __user *restorer;
 322        struct sigframe __user *frame;
 323        int err = 0;
 324        int usig;
 325
 326        frame = get_sigframe(ka, regs, sizeof(*frame));
 327
 328        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 329                goto give_sigsegv;
 330
 331        usig = current_thread_info()->exec_domain
 332                && current_thread_info()->exec_domain->signal_invmap
 333                && sig < 32
 334                ? current_thread_info()->exec_domain->signal_invmap[sig]
 335                : sig;
 336
 337        err = __put_user(usig, &frame->sig);
 338        if (err)
 339                goto give_sigsegv;
 340
 341        err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
 342        if (err)
 343                goto give_sigsegv;
 344
 345        if (_NSIG_WORDS > 1) {
 346                err = __copy_to_user(&frame->extramask, &set->sig[1],
 347                                      sizeof(frame->extramask));
 348                if (err)
 349                        goto give_sigsegv;
 350        }
 351
 352        if (current->binfmt->hasvdso)
 353                restorer = (void *)VDSO_SYM(&__kernel_sigreturn);
 354        else
 355                restorer = (void *)&frame->retcode;
 356        if (ka->sa.sa_flags & SA_RESTORER)
 357                restorer = ka->sa.sa_restorer;
 358
 359        /* Set up to return from userspace.  */
 360        err |= __put_user(restorer, &frame->pretcode);
 361         
 362        /*
 363         * This is popl %eax ; movl $,%eax ; int $0x80
 364         *
 365         * WE DO NOT USE IT ANY MORE! It's only left here for historical
 366         * reasons and because gdb uses it as a signature to notice
 367         * signal handler stack frames.
 368         */
 369        err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 370        err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 371        err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 372
 373        if (err)
 374                goto give_sigsegv;
 375
 376        /* Set up registers for signal handler */
 377        regs->esp = (unsigned long) frame;
 378        regs->eip = (unsigned long) ka->sa.sa_handler;
 379        regs->eax = (unsigned long) sig;
 380        regs->edx = (unsigned long) 0;
 381        regs->ecx = (unsigned long) 0;
 382
 383        set_fs(USER_DS);
 384        regs->xds = __USER_DS;
 385        regs->xes = __USER_DS;
 386        regs->xss = __USER_DS;
 387        regs->xcs = __USER_CS;
 388
 389        /*
 390         * Clear TF when entering the signal handler, but
 391         * notify any tracer that was single-stepping it.
 392         * The tracer may want to single-step inside the
 393         * handler too.
 394         */
 395        regs->eflags &= ~TF_MASK;
 396        if (test_thread_flag(TIF_SINGLESTEP))
 397                ptrace_notify(SIGTRAP);
 398
 399#if DEBUG_SIG
 400        printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
 401                current->comm, current->pid, frame, regs->eip, frame->pretcode);
 402#endif
 403
 404        return 0;
 405
 406give_sigsegv:
 407        force_sigsegv(sig, current);
 408        return -EFAULT;
 409}
 410
 411static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 412                           sigset_t *set, struct pt_regs * regs)
 413{
 414        void __user *restorer;
 415        struct rt_sigframe __user *frame;
 416        int err = 0;
 417        int usig;
 418
 419        frame = get_sigframe(ka, regs, sizeof(*frame));
 420
 421        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 422                goto give_sigsegv;
 423
 424        usig = current_thread_info()->exec_domain
 425                && current_thread_info()->exec_domain->signal_invmap
 426                && sig < 32
 427                ? current_thread_info()->exec_domain->signal_invmap[sig]
 428                : sig;
 429
 430        err |= __put_user(usig, &frame->sig);
 431        err |= __put_user(&frame->info, &frame->pinfo);
 432        err |= __put_user(&frame->uc, &frame->puc);
 433        err |= copy_siginfo_to_user(&frame->info, info);
 434        if (err)
 435                goto give_sigsegv;
 436
 437        /* Create the ucontext.  */
 438        err |= __put_user(0, &frame->uc.uc_flags);
 439        err |= __put_user(0, &frame->uc.uc_link);
 440        err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 441        err |= __put_user(sas_ss_flags(regs->esp),
 442                          &frame->uc.uc_stack.ss_flags);
 443        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 444        err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
 445                                regs, set->sig[0]);
 446        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 447        if (err)
 448                goto give_sigsegv;
 449
 450        /* Set up to return from userspace.  */
 451        restorer = (void *)VDSO_SYM(&__kernel_rt_sigreturn);
 452        if (ka->sa.sa_flags & SA_RESTORER)
 453                restorer = ka->sa.sa_restorer;
 454        err |= __put_user(restorer, &frame->pretcode);
 455         
 456        /*
 457         * This is movl $,%eax ; int $0x80
 458         *
 459         * WE DO NOT USE IT ANY MORE! It's only left here for historical
 460         * reasons and because gdb uses it as a signature to notice
 461         * signal handler stack frames.
 462         */
 463        err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 464        err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 465        err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 466
 467        if (err)
 468                goto give_sigsegv;
 469
 470        /* Set up registers for signal handler */
 471        regs->esp = (unsigned long) frame;
 472        regs->eip = (unsigned long) ka->sa.sa_handler;
 473        regs->eax = (unsigned long) usig;
 474        regs->edx = (unsigned long) &frame->info;
 475        regs->ecx = (unsigned long) &frame->uc;
 476
 477        set_fs(USER_DS);
 478        regs->xds = __USER_DS;
 479        regs->xes = __USER_DS;
 480        regs->xss = __USER_DS;
 481        regs->xcs = __USER_CS;
 482
 483        /*
 484         * Clear TF when entering the signal handler, but
 485         * notify any tracer that was single-stepping it.
 486         * The tracer may want to single-step inside the
 487         * handler too.
 488         */
 489        regs->eflags &= ~TF_MASK;
 490        if (test_thread_flag(TIF_SINGLESTEP))
 491                ptrace_notify(SIGTRAP);
 492
 493#if DEBUG_SIG
 494        printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
 495                current->comm, current->pid, frame, regs->eip, frame->pretcode);
 496#endif
 497
 498        return 0;
 499
 500give_sigsegv:
 501        force_sigsegv(sig, current);
 502        return -EFAULT;
 503}
 504
 505/*
 506 * OK, we're invoking a handler
 507 */     
 508
 509static int
 510handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 511              sigset_t *oldset, struct pt_regs * regs)
 512{
 513        int ret;
 514
 515        /* Are we from a system call? */
 516        if (regs->orig_eax >= 0) {
 517                /* If so, check system call restarting.. */
 518                switch (regs->eax) {
 519                        case -ERESTART_RESTARTBLOCK:
 520                        case -ERESTARTNOHAND:
 521                                regs->eax = -EINTR;
 522                                break;
 523
 524                        case -ERESTARTSYS:
 525                                if (!(ka->sa.sa_flags & SA_RESTART)) {
 526                                        regs->eax = -EINTR;
 527                                        break;
 528                                }
 529                        /* fallthrough */
 530                        case -ERESTARTNOINTR:
 531                                regs->eax = regs->orig_eax;
 532                                regs->eip -= 2;
 533                }
 534        }
 535
 536        /*
 537         * If TF is set due to a debugger (PT_DTRACE), clear the TF flag so
 538         * that register information in the sigcontext is correct.
 539         */
 540        if (unlikely(regs->eflags & TF_MASK)
 541            && likely(current->ptrace & PT_DTRACE)) {
 542                current->ptrace &= ~PT_DTRACE;
 543                regs->eflags &= ~TF_MASK;
 544        }
 545
 546        /* Set up the stack frame */
 547        if (ka->sa.sa_flags & SA_SIGINFO)
 548                ret = setup_rt_frame(sig, ka, info, oldset, regs);
 549        else
 550                ret = setup_frame(sig, ka, oldset, regs);
 551
 552        if (ret == 0) {
 553                spin_lock_irq(&current->sighand->siglock);
 554                sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 555                if (!(ka->sa.sa_flags & SA_NODEFER))
 556                        sigaddset(&current->blocked,sig);
 557                recalc_sigpending();
 558                spin_unlock_irq(&current->sighand->siglock);
 559        }
 560
 561        return ret;
 562}
 563
 564/*
 565 * Note that 'init' is a special process: it doesn't get signals it doesn't
 566 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 567 * mistake.
 568 */
 569static void fastcall do_signal(struct pt_regs *regs)
 570{
 571        siginfo_t info;
 572        int signr;
 573        struct k_sigaction ka;
 574        sigset_t *oldset;
 575
 576        /*
 577         * We want the common case to go fast, which
 578         * is why we may in certain cases get here from
 579         * kernel mode. Just return without doing anything
 580         * if so.  vm86 regs switched out by assembly code
 581         * before reaching here, so testing against kernel
 582         * CS suffices.
 583         */
 584        if (!user_mode(regs))
 585                return;
 586
 587        if (test_thread_flag(TIF_RESTORE_SIGMASK))
 588                oldset = &current->saved_sigmask;
 589        else
 590                oldset = &current->blocked;
 591
 592        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 593        if (signr > 0) {
 594                /* Reenable any watchpoints before delivering the
 595                 * signal to user space. The processor register will
 596                 * have been cleared if the watchpoint triggered
 597                 * inside the kernel.
 598                 */
 599                if (unlikely(current->thread.debugreg[7]))
 600                        set_debugreg(current->thread.debugreg[7], 7);
 601
 602                /* Whee!  Actually deliver the signal.  */
 603                if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 604                        /* a signal was successfully delivered; the saved
 605                         * sigmask will have been stored in the signal frame,
 606                         * and will be restored by sigreturn, so we can simply
 607                         * clear the TIF_RESTORE_SIGMASK flag */
 608                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
 609                                clear_thread_flag(TIF_RESTORE_SIGMASK);
 610                }
 611
 612                return;
 613        }
 614
 615        /* Did we come from a system call? */
 616        if (regs->orig_eax >= 0) {
 617                /* Restart the system call - no handlers present */
 618                switch (regs->eax) {
 619                case -ERESTARTNOHAND:
 620                case -ERESTARTSYS:
 621                case -ERESTARTNOINTR:
 622                        regs->eax = regs->orig_eax;
 623                        regs->eip -= 2;
 624                        break;
 625
 626                case -ERESTART_RESTARTBLOCK:
 627                        regs->eax = __NR_restart_syscall;
 628                        regs->eip -= 2;
 629                        break;
 630                }
 631        }
 632
 633        /* if there's no signal to deliver, we just put the saved sigmask
 634         * back */
 635        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 636                clear_thread_flag(TIF_RESTORE_SIGMASK);
 637                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 638        }
 639}
 640
 641/*
 642 * notification of userspace execution resumption
 643 * - triggered by the TIF_WORK_MASK flags
 644 */
 645__attribute__((regparm(3)))
 646void do_notify_resume(struct pt_regs *regs, void *_unused,
 647                      __u32 thread_info_flags)
 648{
 649        /* Pending single-step? */
 650        if (thread_info_flags & _TIF_SINGLESTEP) {
 651                regs->eflags |= TF_MASK;
 652                clear_thread_flag(TIF_SINGLESTEP);
 653        }
 654
 655        /* deal with pending signal delivery */
 656        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 657                do_signal(regs);
 658        
 659        clear_thread_flag(TIF_IRET);
 660}
 661