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/smp_lock.h>
  14 #include <linux/kernel.h>
  15 #include <linux/signal.h>
  16 #include <linux/errno.h>
  17 #include <linux/wait.h>
  18 #include <linux/unistd.h>
  19 #include <linux/stddef.h>
  20 #include <linux/personality.h>
  21 #include <linux/suspend.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/elf.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  */
  37 asmlinkage int
  38 sys_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
  53 asmlinkage int
  54 sys_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
  85 asmlinkage int
  86 sys_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
 101 static int
 102 restore_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         COPY_SEG(gs);
 132         GET_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
 172 badframe:
 173         return 1;
 174 }
 175
 176 asmlinkage 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
 201 badframe:
 202         force_sig(SIGSEGV, current);
 203         return 0;
 204 }
 205
 206 asmlinkage 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
 232 badframe:
 233         force_sig(SIGSEGV, current);
 234         return 0;
 235 }
 236
 237 /*
 238  * Set up a signal frame.
 239  */
 240
 241 static int
 242 setup_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->xgs, (unsigned int __user *)&sc->gs);
 248         savesegment(fs, tmp);
 249         err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
 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  */
 285 static inline void __user *
 286 get_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.  */
 315 extern void __user __kernel_sigreturn;
 316 extern void __user __kernel_rt_sigreturn;
 317
 318 static 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         restorer = (void *)VDSO_SYM(&__kernel_sigreturn);
 353         if (ka->sa.sa_flags & SA_RESTORER)
 354                 restorer = ka->sa.sa_restorer;
 355
 356         /* Set up to return from userspace.  */
 357         err |= __put_user(restorer, &frame->pretcode);
 358
 359         /*
 360          * This is popl %eax ; movl $,%eax ; int $0x80
 361          *
 362          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 363          * reasons and because gdb uses it as a signature to notice
 364          * signal handler stack frames.
 365          */
 366         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 367         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 368         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 369
 370         if (err)
 371                 goto give_sigsegv;
 372
 373         /* Set up registers for signal handler */
 374         regs->esp = (unsigned long) frame;
 375         regs->eip = (unsigned long) ka->sa.sa_handler;
 376         regs->eax = (unsigned long) sig;
 377         regs->edx = (unsigned long) 0;
 378         regs->ecx = (unsigned long) 0;
 379
 380         set_fs(USER_DS);
 381         regs->xds = __USER_DS;
 382         regs->xes = __USER_DS;
 383         regs->xss = __USER_DS;
 384         regs->xcs = __USER_CS;
 385
 386         /*
 387          * Clear TF when entering the signal handler, but
 388          * notify any tracer that was single-stepping it.
 389          * The tracer may want to single-step inside the
 390          * handler too.
 391          */
 392         regs->eflags &= ~TF_MASK;
 393         if (test_thread_flag(TIF_SINGLESTEP))
 394                 ptrace_notify(SIGTRAP);
 395
 396 #if DEBUG_SIG
 397         printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
 398                 current->comm, current->pid, frame, regs->eip, frame->pretcode);
 399 #endif
 400
 401         return 0;
 402
 403 give_sigsegv:
 404         force_sigsegv(sig, current);
 405         return -EFAULT;
 406 }
 407
 408 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 409                            sigset_t *set, struct pt_regs * regs)
 410 {
 411         void __user *restorer;
 412         struct rt_sigframe __user *frame;
 413         int err = 0;
 414         int usig;
 415
 416         frame = get_sigframe(ka, regs, sizeof(*frame));
 417
 418         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 419                 goto give_sigsegv;
 420
 421         usig = current_thread_info()->exec_domain
 422                 && current_thread_info()->exec_domain->signal_invmap
 423                 && sig < 32
 424                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 425                 : sig;
 426
 427         err |= __put_user(usig, &frame->sig);
 428         err |= __put_user(&frame->info, &frame->pinfo);
 429         err |= __put_user(&frame->uc, &frame->puc);
 430         err |= copy_siginfo_to_user(&frame->info, info);
 431         if (err)
 432                 goto give_sigsegv;
 433
 434         /* Create the ucontext.  */
 435         err |= __put_user(0, &frame->uc.uc_flags);
 436         err |= __put_user(0, &frame->uc.uc_link);
 437         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 438         err |= __put_user(sas_ss_flags(regs->esp),
 439                           &frame->uc.uc_stack.ss_flags);
 440         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 441         err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
 442                                 regs, set->sig[0]);
 443         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 444         if (err)
 445                 goto give_sigsegv;
 446
 447         /* Set up to return from userspace.  */
 448         restorer = (void *)VDSO_SYM(&__kernel_rt_sigreturn);
 449         if (ka->sa.sa_flags & SA_RESTORER)
 450                 restorer = ka->sa.sa_restorer;
 451         err |= __put_user(restorer, &frame->pretcode);
 452
 453         /*
 454          * This is movl $,%eax ; int $0x80
 455          *
 456          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 457          * reasons and because gdb uses it as a signature to notice
 458          * signal handler stack frames.
 459          */
 460         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 461         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 462         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 463
 464         if (err)
 465                 goto give_sigsegv;
 466
 467         /* Set up registers for signal handler */
 468         regs->esp = (unsigned long) frame;
 469         regs->eip = (unsigned long) ka->sa.sa_handler;
 470         regs->eax = (unsigned long) usig;
 471         regs->edx = (unsigned long) &frame->info;
 472         regs->ecx = (unsigned long) &frame->uc;
 473
 474         set_fs(USER_DS);
 475         regs->xds = __USER_DS;
 476         regs->xes = __USER_DS;
 477         regs->xss = __USER_DS;
 478         regs->xcs = __USER_CS;
 479
 480         /*
 481          * Clear TF when entering the signal handler, but
 482          * notify any tracer that was single-stepping it.
 483          * The tracer may want to single-step inside the
 484          * handler too.
 485          */
 486         regs->eflags &= ~TF_MASK;
 487         if (test_thread_flag(TIF_SINGLESTEP))
 488                 ptrace_notify(SIGTRAP);
 489
 490 #if DEBUG_SIG
 491         printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
 492                 current->comm, current->pid, frame, regs->eip, frame->pretcode);
 493 #endif
 494
 495         return 0;
 496
 497 give_sigsegv:
 498         force_sigsegv(sig, current);
 499         return -EFAULT;
 500 }
 501
 502 /*
 503  * OK, we're invoking a handler
 504  */
 505
 506 static int
 507 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 508               sigset_t *oldset, struct pt_regs * regs)
 509 {
 510         int ret;
 511
 512         /* Are we from a system call? */
 513         if (regs->orig_eax >= 0) {
 514                 /* If so, check system call restarting.. */
 515                 switch (regs->eax) {
 516                         case -ERESTART_RESTARTBLOCK:
 517                         case -ERESTARTNOHAND:
 518                                 regs->eax = -EINTR;
 519                                 break;
 520
 521                         case -ERESTARTSYS:
 522                                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 523                                         regs->eax = -EINTR;
 524                                         break;
 525                                 }
 526                         /* fallthrough */
 527                         case -ERESTARTNOINTR:
 528                                 regs->eax = regs->orig_eax;
 529                                 regs->eip -= 2;
 530                 }
 531         }
 532
 533         /*
 534          * If TF is set due to a debugger (PT_DTRACE), clear the TF flag so
 535          * that register information in the sigcontext is correct.
 536          */
 537         if (unlikely(regs->eflags & TF_MASK)
 538             && likely(current->ptrace & PT_DTRACE)) {
 539                 current->ptrace &= ~PT_DTRACE;
 540                 regs->eflags &= ~TF_MASK;
 541         }
 542
 543         /* Set up the stack frame */
 544         if (ka->sa.sa_flags & SA_SIGINFO)
 545                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 546         else
 547                 ret = setup_frame(sig, ka, oldset, regs);
 548
 549         if (ret == 0) {
 550                 spin_lock_irq(&current->sighand->siglock);
 551                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 552                 if (!(ka->sa.sa_flags & SA_NODEFER))
 553                         sigaddset(&current->blocked,sig);
 554                 recalc_sigpending();
 555                 spin_unlock_irq(&current->sighand->siglock);
 556         }
 557
 558         return ret;
 559 }
 560
 561 /*
 562  * Note that 'init' is a special process: it doesn't get signals it doesn't
 563  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 564  * mistake.
 565  */
 566 static void fastcall do_signal(struct pt_regs *regs)
 567 {
 568         siginfo_t info;
 569         int signr;
 570         struct k_sigaction ka;
 571         sigset_t *oldset;
 572
 573         /*
 574          * We want the common case to go fast, which
 575          * is why we may in certain cases get here from
 576          * kernel mode. Just return without doing anything
 577          * if so.  vm86 regs switched out by assembly code
 578          * before reaching here, so testing against kernel
 579          * CS suffices.
 580          */
 581         if (!user_mode(regs))
 582                 return;
 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                 /* Reenable any watchpoints before delivering the
 592                  * signal to user space. The processor register will
 593                  * have been cleared if the watchpoint triggered
 594                  * inside the kernel.
 595                  */
 596                 if (unlikely(current->thread.debugreg[7]))
 597                         set_debugreg(current->thread.debugreg[7], 7);
 598
 599                 /* Whee!  Actually deliver the signal.  */
 600                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 601                         /* a signal was successfully delivered; the saved
 602                          * sigmask will have been stored in the signal frame,
 603                          * and will be restored by sigreturn, so we can simply
 604                          * clear the TIF_RESTORE_SIGMASK flag */
 605                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 606                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 607                 }
 608
 609                 return;
 610         }
 611
 612         /* Did we come from a system call? */
 613         if (regs->orig_eax >= 0) {
 614                 /* Restart the system call - no handlers present */
 615                 switch (regs->eax) {
 616                 case -ERESTARTNOHAND:
 617                 case -ERESTARTSYS:
 618                 case -ERESTARTNOINTR:
 619                         regs->eax = regs->orig_eax;
 620                         regs->eip -= 2;
 621                         break;
 622
 623                 case -ERESTART_RESTARTBLOCK:
 624                         regs->eax = __NR_restart_syscall;
 625                         regs->eip -= 2;
 626                         break;
 627                 }
 628         }
 629
 630         /* if there's no signal to deliver, we just put the saved sigmask
 631          * back */
 632         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 633                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 634                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 635         }
 636 }
 637
 638 /*
 639  * notification of userspace execution resumption
 640  * - triggered by the TIF_WORK_MASK flags
 641  */
 642 __attribute__((regparm(3)))
 643 void do_notify_resume(struct pt_regs *regs, void *_unused,
 644                       __u32 thread_info_flags)
 645 {
 646         /* Pending single-step? */
 647         if (thread_info_flags & _TIF_SINGLESTEP) {
 648                 regs->eflags |= TF_MASK;
 649                 clear_thread_flag(TIF_SINGLESTEP);
 650         }
 651
 652         /* deal with pending signal delivery */
 653         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 654                 do_signal(regs);
 655
 656         clear_thread_flag(TIF_IRET);
 657 }