arch/x86/kernel/signal_32.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *
   4  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   5  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
   6  */
   7 #include <linux/list.h>
   8
   9 #include <linux/personality.h>
  10 #include <linux/binfmts.h>
  11 #include <linux/suspend.h>
  12 #include <linux/kernel.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/signal.h>
  15 #include <linux/stddef.h>
  16 #include <linux/unistd.h>
  17 #include <linux/errno.h>
  18 #include <linux/sched.h>
  19 #include <linux/wait.h>
  20 #include <linux/elf.h>
  21 #include <linux/smp.h>
  22 #include <linux/mm.h>
  23
  24 #include <asm/processor.h>
  25 #include <asm/ucontext.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/i387.h>
  28 #include <asm/vdso.h>
  29
  30 #include "sigframe.h"
  31
  32 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  33
  34 #define __FIX_EFLAGS    (X86_EFLAGS_AC | X86_EFLAGS_OF | \
  35                          X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
  36                          X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
  37                          X86_EFLAGS_CF)
  38
  39 #ifdef CONFIG_X86_32
  40 # define FIX_EFLAGS     (__FIX_EFLAGS | X86_EFLAGS_RF)
  41 #else
  42 # define FIX_EFLAGS     __FIX_EFLAGS
  43 #endif
  44
  45 /*
  46  * Atomically swap in the new signal mask, and wait for a signal.
  47  */
  48 asmlinkage int
  49 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  50 {
  51         mask &= _BLOCKABLE;
  52         spin_lock_irq(&current->sighand->siglock);
  53         current->saved_sigmask = current->blocked;
  54         siginitset(&current->blocked, mask);
  55         recalc_sigpending();
  56         spin_unlock_irq(&current->sighand->siglock);
  57
  58         current->state = TASK_INTERRUPTIBLE;
  59         schedule();
  60         set_restore_sigmask();
  61
  62         return -ERESTARTNOHAND;
  63 }
  64
  65 asmlinkage int
  66 sys_sigaction(int sig, const struct old_sigaction __user *act,
  67               struct old_sigaction __user *oact)
  68 {
  69         struct k_sigaction new_ka, old_ka;
  70         int ret;
  71
  72         if (act) {
  73                 old_sigset_t mask;
  74
  75                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  76                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  77                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  78                         return -EFAULT;
  79
  80                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  81                 __get_user(mask, &act->sa_mask);
  82                 siginitset(&new_ka.sa.sa_mask, mask);
  83         }
  84
  85         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  86
  87         if (!ret && oact) {
  88                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  89                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  90                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  91                         return -EFAULT;
  92
  93                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  94                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  95         }
  96
  97         return ret;
  98 }
  99
 100 asmlinkage int sys_sigaltstack(unsigned long bx)
 101 {
 102         /*
 103          * This is needed to make gcc realize it doesn't own the
 104          * "struct pt_regs"
 105          */
 106         struct pt_regs *regs = (struct pt_regs *)&bx;
 107         const stack_t __user *uss = (const stack_t __user *)bx;
 108         stack_t __user *uoss = (stack_t __user *)regs->cx;
 109
 110         return do_sigaltstack(uss, uoss, regs->sp);
 111 }
 112
 113
 114 /*
 115  * Do a signal return; undo the signal stack.
 116  */
 117 static int
 118 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 119                    unsigned long *pax)
 120 {
 121         unsigned int err = 0;
 122
 123         /* Always make any pending restarted system calls return -EINTR */
 124         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 125
 126 #define COPY(x)         err |= __get_user(regs->x, &sc->x)
 127
 128 #define COPY_SEG(seg)                                                   \
 129         { unsigned short tmp;                                           \
 130           err |= __get_user(tmp, &sc->seg);                             \
 131           regs->seg = tmp; }
 132
 133 #define COPY_SEG_STRICT(seg)                                            \
 134         { unsigned short tmp;                                           \
 135           err |= __get_user(tmp, &sc->seg);                             \
 136           regs->seg = tmp|3; }
 137
 138 #define GET_SEG(seg)                                                    \
 139         { unsigned short tmp;                                           \
 140           err |= __get_user(tmp, &sc->seg);                             \
 141           loadsegment(seg, tmp); }
 142
 143         GET_SEG(gs);
 144         COPY_SEG(fs);
 145         COPY_SEG(es);
 146         COPY_SEG(ds);
 147         COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
 148         COPY(dx); COPY(cx); COPY(ip);
 149         COPY_SEG_STRICT(cs);
 150         COPY_SEG_STRICT(ss);
 151
 152         {
 153                 unsigned int tmpflags;
 154
 155                 err |= __get_user(tmpflags, &sc->flags);
 156                 regs->flags = (regs->flags & ~FIX_EFLAGS) |
 157                                                 (tmpflags & FIX_EFLAGS);
 158                 regs->orig_ax = -1;             /* disable syscall checks */
 159         }
 160
 161         {
 162                 void __user *buf;
 163
 164                 err |= __get_user(buf, &sc->fpstate);
 165                 err |= restore_i387_xstate(buf);
 166         }
 167
 168         err |= __get_user(*pax, &sc->ax);
 169         return err;
 170 }
 171
 172 asmlinkage unsigned long sys_sigreturn(unsigned long __unused)
 173 {
 174         struct sigframe __user *frame;
 175         struct pt_regs *regs;
 176         unsigned long ax;
 177         sigset_t set;
 178
 179         regs = (struct pt_regs *) &__unused;
 180         frame = (struct sigframe __user *)(regs->sp - 8);
 181
 182         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 183                 goto badframe;
 184         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 185                 && __copy_from_user(&set.sig[1], &frame->extramask,
 186                                     sizeof(frame->extramask))))
 187                 goto badframe;
 188
 189         sigdelsetmask(&set, ~_BLOCKABLE);
 190         spin_lock_irq(&current->sighand->siglock);
 191         current->blocked = set;
 192         recalc_sigpending();
 193         spin_unlock_irq(&current->sighand->siglock);
 194
 195         if (restore_sigcontext(regs, &frame->sc, &ax))
 196                 goto badframe;
 197         return ax;
 198
 199 badframe:
 200         if (show_unhandled_signals && printk_ratelimit()) {
 201                 printk("%s%s[%d] bad frame in sigreturn frame:"
 202                         "%p ip:%lx sp:%lx oeax:%lx",
 203                     task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 204                     current->comm, task_pid_nr(current), frame, regs->ip,
 205                     regs->sp, regs->orig_ax);
 206                 print_vma_addr(" in ", regs->ip);
 207                 printk(KERN_CONT "\n");
 208         }
 209
 210         force_sig(SIGSEGV, current);
 211
 212         return 0;
 213 }
 214
 215 asmlinkage int sys_rt_sigreturn(unsigned long __unused)
 216 {
 217         struct pt_regs *regs = (struct pt_regs *)&__unused;
 218         struct rt_sigframe __user *frame;
 219         unsigned long ax;
 220         sigset_t set;
 221
 222         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 223         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 224                 goto badframe;
 225         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 226                 goto badframe;
 227
 228         sigdelsetmask(&set, ~_BLOCKABLE);
 229         spin_lock_irq(&current->sighand->siglock);
 230         current->blocked = set;
 231         recalc_sigpending();
 232         spin_unlock_irq(&current->sighand->siglock);
 233
 234         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 235                 goto badframe;
 236
 237         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 238                 goto badframe;
 239
 240         return ax;
 241
 242 badframe:
 243         force_sig(SIGSEGV, current);
 244         return 0;
 245 }
 246
 247 /*
 248  * Set up a signal frame.
 249  */
 250 static int
 251 setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 252                  struct pt_regs *regs, unsigned long mask)
 253 {
 254         int tmp, err = 0;
 255
 256         err |= __put_user(regs->fs, (unsigned int __user *)&sc->fs);
 257         savesegment(gs, tmp);
 258         err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
 259
 260         err |= __put_user(regs->es, (unsigned int __user *)&sc->es);
 261         err |= __put_user(regs->ds, (unsigned int __user *)&sc->ds);
 262         err |= __put_user(regs->di, &sc->di);
 263         err |= __put_user(regs->si, &sc->si);
 264         err |= __put_user(regs->bp, &sc->bp);
 265         err |= __put_user(regs->sp, &sc->sp);
 266         err |= __put_user(regs->bx, &sc->bx);
 267         err |= __put_user(regs->dx, &sc->dx);
 268         err |= __put_user(regs->cx, &sc->cx);
 269         err |= __put_user(regs->ax, &sc->ax);
 270         err |= __put_user(current->thread.trap_no, &sc->trapno);
 271         err |= __put_user(current->thread.error_code, &sc->err);
 272         err |= __put_user(regs->ip, &sc->ip);
 273         err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
 274         err |= __put_user(regs->flags, &sc->flags);
 275         err |= __put_user(regs->sp, &sc->sp_at_signal);
 276         err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
 277
 278         tmp = save_i387_xstate(fpstate);
 279         if (tmp < 0)
 280                 err = 1;
 281         else
 282                 err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
 283
 284         /* non-iBCS2 extensions.. */
 285         err |= __put_user(mask, &sc->oldmask);
 286         err |= __put_user(current->thread.cr2, &sc->cr2);
 287
 288         return err;
 289 }
 290
 291 /*
 292  * Determine which stack to use..
 293  */
 294 static inline void __user *
 295 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 296              void **fpstate)
 297 {
 298         unsigned long sp;
 299
 300         /* Default to using normal stack */
 301         sp = regs->sp;
 302
 303         /*
 304          * If we are on the alternate signal stack and would overflow it, don't.
 305          * Return an always-bogus address instead so we will die with SIGSEGV.
 306          */
 307         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
 308                 return (void __user *) -1L;
 309
 310         /* This is the X/Open sanctioned signal stack switching.  */
 311         if (ka->sa.sa_flags & SA_ONSTACK) {
 312                 if (sas_ss_flags(sp) == 0)
 313                         sp = current->sas_ss_sp + current->sas_ss_size;
 314         } else {
 315                 /* This is the legacy signal stack switching. */
 316                 if ((regs->ss & 0xffff) != __USER_DS &&
 317                         !(ka->sa.sa_flags & SA_RESTORER) &&
 318                                 ka->sa.sa_restorer)
 319                         sp = (unsigned long) ka->sa.sa_restorer;
 320         }
 321
 322         if (used_math()) {
 323                 sp = sp - sig_xstate_size;
 324                 *fpstate = (struct _fpstate *) sp;
 325         }
 326
 327         sp -= frame_size;
 328         /*
 329          * Align the stack pointer according to the i386 ABI,
 330          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 331          */
 332         sp = ((sp + 4) & -16ul) - 4;
 333
 334         return (void __user *) sp;
 335 }
 336
 337 static int
 338 setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 339             struct pt_regs *regs)
 340 {
 341         struct sigframe __user *frame;
 342         void __user *restorer;
 343         int err = 0;
 344         int usig;
 345         void __user *fpstate = NULL;
 346
 347         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 348
 349         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 350                 goto give_sigsegv;
 351
 352         usig = current_thread_info()->exec_domain
 353                 && current_thread_info()->exec_domain->signal_invmap
 354                 && sig < 32
 355                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 356                 : sig;
 357
 358         err = __put_user(usig, &frame->sig);
 359         if (err)
 360                 goto give_sigsegv;
 361
 362         err = setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]);
 363         if (err)
 364                 goto give_sigsegv;
 365
 366         if (_NSIG_WORDS > 1) {
 367                 err = __copy_to_user(&frame->extramask, &set->sig[1],
 368                                       sizeof(frame->extramask));
 369                 if (err)
 370                         goto give_sigsegv;
 371         }
 372
 373         if (current->mm->context.vdso)
 374                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 375         else
 376                 restorer = &frame->retcode;
 377         if (ka->sa.sa_flags & SA_RESTORER)
 378                 restorer = ka->sa.sa_restorer;
 379
 380         /* Set up to return from userspace.  */
 381         err |= __put_user(restorer, &frame->pretcode);
 382
 383         /*
 384          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 385          *
 386          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 387          * reasons and because gdb uses it as a signature to notice
 388          * signal handler stack frames.
 389          */
 390         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 391         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 392         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 393
 394         if (err)
 395                 goto give_sigsegv;
 396
 397         /* Set up registers for signal handler */
 398         regs->sp = (unsigned long)frame;
 399         regs->ip = (unsigned long)ka->sa.sa_handler;
 400         regs->ax = (unsigned long)sig;
 401         regs->dx = 0;
 402         regs->cx = 0;
 403
 404         regs->ds = __USER_DS;
 405         regs->es = __USER_DS;
 406         regs->ss = __USER_DS;
 407         regs->cs = __USER_CS;
 408
 409         return 0;
 410
 411 give_sigsegv:
 412         force_sigsegv(sig, current);
 413         return -EFAULT;
 414 }
 415
 416 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 417                           sigset_t *set, struct pt_regs *regs)
 418 {
 419         struct rt_sigframe __user *frame;
 420         void __user *restorer;
 421         int err = 0;
 422         int usig;
 423         void __user *fpstate = NULL;
 424
 425         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 426
 427         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 428                 goto give_sigsegv;
 429
 430         usig = current_thread_info()->exec_domain
 431                 && current_thread_info()->exec_domain->signal_invmap
 432                 && sig < 32
 433                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 434                 : sig;
 435
 436         err |= __put_user(usig, &frame->sig);
 437         err |= __put_user(&frame->info, &frame->pinfo);
 438         err |= __put_user(&frame->uc, &frame->puc);
 439         err |= copy_siginfo_to_user(&frame->info, info);
 440         if (err)
 441                 goto give_sigsegv;
 442
 443         /* Create the ucontext.  */
 444         err |= __put_user(0, &frame->uc.uc_flags);
 445         err |= __put_user(0, &frame->uc.uc_link);
 446         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 447         err |= __put_user(sas_ss_flags(regs->sp),
 448                           &frame->uc.uc_stack.ss_flags);
 449         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 450         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 451                                 regs, set->sig[0]);
 452         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 453         if (err)
 454                 goto give_sigsegv;
 455
 456         /* Set up to return from userspace.  */
 457         restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 458         if (ka->sa.sa_flags & SA_RESTORER)
 459                 restorer = ka->sa.sa_restorer;
 460         err |= __put_user(restorer, &frame->pretcode);
 461
 462         /*
 463          * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 464          *
 465          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 466          * reasons and because gdb uses it as a signature to notice
 467          * signal handler stack frames.
 468          */
 469         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 470         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 471         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 472
 473         if (err)
 474                 goto give_sigsegv;
 475
 476         /* Set up registers for signal handler */
 477         regs->sp = (unsigned long)frame;
 478         regs->ip = (unsigned long)ka->sa.sa_handler;
 479         regs->ax = (unsigned long)usig;
 480         regs->dx = (unsigned long)&frame->info;
 481         regs->cx = (unsigned long)&frame->uc;
 482
 483         regs->ds = __USER_DS;
 484         regs->es = __USER_DS;
 485         regs->ss = __USER_DS;
 486         regs->cs = __USER_CS;
 487
 488         return 0;
 489
 490 give_sigsegv:
 491         force_sigsegv(sig, current);
 492         return -EFAULT;
 493 }
 494
 495 /*
 496  * OK, we're invoking a handler:
 497  */
 498 static int
 499 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 500               sigset_t *oldset, struct pt_regs *regs)
 501 {
 502         int ret;
 503
 504         /* Are we from a system call? */
 505         if ((long)regs->orig_ax >= 0) {
 506                 /* If so, check system call restarting.. */
 507                 switch (regs->ax) {
 508                 case -ERESTART_RESTARTBLOCK:
 509                 case -ERESTARTNOHAND:
 510                         regs->ax = -EINTR;
 511                         break;
 512
 513                 case -ERESTARTSYS:
 514                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 515                                 regs->ax = -EINTR;
 516                                 break;
 517                         }
 518                 /* fallthrough */
 519                 case -ERESTARTNOINTR:
 520                         regs->ax = regs->orig_ax;
 521                         regs->ip -= 2;
 522                         break;
 523                 }
 524         }
 525
 526         /*
 527          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 528          * flag so that register information in the sigcontext is correct.
 529          */
 530         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 531             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 532                 regs->flags &= ~X86_EFLAGS_TF;
 533
 534         /* Set up the stack frame */
 535         if (ka->sa.sa_flags & SA_SIGINFO)
 536                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 537         else
 538                 ret = setup_frame(sig, ka, oldset, regs);
 539
 540         if (ret)
 541                 return ret;
 542
 543         /*
 544          * Clear the direction flag as per the ABI for function entry.
 545          */
 546         regs->flags &= ~X86_EFLAGS_DF;
 547
 548         /*
 549          * Clear TF when entering the signal handler, but
 550          * notify any tracer that was single-stepping it.
 551          * The tracer may want to single-step inside the
 552          * handler too.
 553          */
 554         regs->flags &= ~X86_EFLAGS_TF;
 555         if (test_thread_flag(TIF_SINGLESTEP))
 556                 ptrace_notify(SIGTRAP);
 557
 558         spin_lock_irq(&current->sighand->siglock);
 559         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 560         if (!(ka->sa.sa_flags & SA_NODEFER))
 561                 sigaddset(&current->blocked, sig);
 562         recalc_sigpending();
 563         spin_unlock_irq(&current->sighand->siglock);
 564
 565         return 0;
 566 }
 567
 568 /*
 569  * Note that 'init' is a special process: it doesn't get signals it doesn't
 570  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 571  * mistake.
 572  */
 573 static void do_signal(struct pt_regs *regs)
 574 {
 575         struct k_sigaction ka;
 576         siginfo_t info;
 577         int signr;
 578         sigset_t *oldset;
 579
 580         /*
 581          * We want the common case to go fast, which is why we may in certain
 582          * cases get here from kernel mode. Just return without doing anything
 583          * if so.
 584          * X86_32: vm86 regs switched out by assembly code before reaching
 585          * here, so testing against kernel CS suffices.
 586          */
 587         if (!user_mode(regs))
 588                 return;
 589
 590         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 591                 oldset = &current->saved_sigmask;
 592         else
 593                 oldset = &current->blocked;
 594
 595         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 596         if (signr > 0) {
 597                 /*
 598                  * Re-enable any watchpoints before delivering the
 599                  * signal to user space. The processor register will
 600                  * have been cleared if the watchpoint triggered
 601                  * inside the kernel.
 602                  */
 603                 if (current->thread.debugreg7)
 604                         set_debugreg(current->thread.debugreg7, 7);
 605
 606                 /* Whee! Actually deliver the signal.  */
 607                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 608                         /*
 609                          * A signal was successfully delivered; the saved
 610                          * sigmask will have been stored in the signal frame,
 611                          * and will be restored by sigreturn, so we can simply
 612                          * clear the TS_RESTORE_SIGMASK flag.
 613                          */
 614                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 615                 }
 616                 return;
 617         }
 618
 619         /* Did we come from a system call? */
 620         if ((long)regs->orig_ax >= 0) {
 621                 /* Restart the system call - no handlers present */
 622                 switch (regs->ax) {
 623                 case -ERESTARTNOHAND:
 624                 case -ERESTARTSYS:
 625                 case -ERESTARTNOINTR:
 626                         regs->ax = regs->orig_ax;
 627                         regs->ip -= 2;
 628                         break;
 629
 630                 case -ERESTART_RESTARTBLOCK:
 631                         regs->ax = __NR_restart_syscall;
 632                         regs->ip -= 2;
 633                         break;
 634                 }
 635         }
 636
 637         /*
 638          * If there's no signal to deliver, we just put the saved sigmask
 639          * back.
 640          */
 641         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 642                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 643                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 644         }
 645 }
 646
 647 /*
 648  * notification of userspace execution resumption
 649  * - triggered by the TIF_WORK_MASK flags
 650  */
 651 void
 652 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 653 {
 654         /* deal with pending signal delivery */
 655         if (thread_info_flags & _TIF_SIGPENDING)
 656                 do_signal(regs);
 657
 658         clear_thread_flag(TIF_IRET);
 659 }