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/tracehook.h>
  21 #include <linux/elf.h>
  22 #include <linux/smp.h>
  23 #include <linux/mm.h>
  24
  25 #include <asm/processor.h>
  26 #include <asm/ucontext.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/i387.h>
  29 #include <asm/vdso.h>
  30 #include <asm/syscall.h>
  31 #include <asm/syscalls.h>
  32
  33 #include "sigframe.h"
  34
  35 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  36
  37 #define __FIX_EFLAGS    (X86_EFLAGS_AC | X86_EFLAGS_OF | \
  38                          X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
  39                          X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
  40                          X86_EFLAGS_CF)
  41
  42 #ifdef CONFIG_X86_32
  43 # define FIX_EFLAGS     (__FIX_EFLAGS | X86_EFLAGS_RF)
  44 #else
  45 # define FIX_EFLAGS     __FIX_EFLAGS
  46 #endif
  47
  48 /*
  49  * Atomically swap in the new signal mask, and wait for a signal.
  50  */
  51 asmlinkage int
  52 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  53 {
  54         mask &= _BLOCKABLE;
  55         spin_lock_irq(&current->sighand->siglock);
  56         current->saved_sigmask = current->blocked;
  57         siginitset(&current->blocked, mask);
  58         recalc_sigpending();
  59         spin_unlock_irq(&current->sighand->siglock);
  60
  61         current->state = TASK_INTERRUPTIBLE;
  62         schedule();
  63         set_restore_sigmask();
  64
  65         return -ERESTARTNOHAND;
  66 }
  67
  68 asmlinkage int
  69 sys_sigaction(int sig, const struct old_sigaction __user *act,
  70               struct old_sigaction __user *oact)
  71 {
  72         struct k_sigaction new_ka, old_ka;
  73         int ret;
  74
  75         if (act) {
  76                 old_sigset_t mask;
  77
  78                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  79                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  80                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  81                         return -EFAULT;
  82
  83                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  84                 __get_user(mask, &act->sa_mask);
  85                 siginitset(&new_ka.sa.sa_mask, mask);
  86         }
  87
  88         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  89
  90         if (!ret && oact) {
  91                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  92                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  93                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  94                         return -EFAULT;
  95
  96                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  97                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  98         }
  99
 100         return ret;
 101 }
 102
 103 asmlinkage int sys_sigaltstack(unsigned long bx)
 104 {
 105         /*
 106          * This is needed to make gcc realize it doesn't own the
 107          * "struct pt_regs"
 108          */
 109         struct pt_regs *regs = (struct pt_regs *)&bx;
 110         const stack_t __user *uss = (const stack_t __user *)bx;
 111         stack_t __user *uoss = (stack_t __user *)regs->cx;
 112
 113         return do_sigaltstack(uss, uoss, regs->sp);
 114 }
 115
 116
 117 /*
 118  * Do a signal return; undo the signal stack.
 119  */
 120 static int
 121 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 122                    unsigned long *pax)
 123 {
 124         unsigned int err = 0;
 125
 126         /* Always make any pending restarted system calls return -EINTR */
 127         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 128
 129 #define COPY(x)         err |= __get_user(regs->x, &sc->x)
 130
 131 #define COPY_SEG(seg)                                                   \
 132         { unsigned short tmp;                                           \
 133           err |= __get_user(tmp, &sc->seg);                             \
 134           regs->seg = tmp; }
 135
 136 #define COPY_SEG_STRICT(seg)                                            \
 137         { unsigned short tmp;                                           \
 138           err |= __get_user(tmp, &sc->seg);                             \
 139           regs->seg = tmp|3; }
 140
 141 #define GET_SEG(seg)                                                    \
 142         { unsigned short tmp;                                           \
 143           err |= __get_user(tmp, &sc->seg);                             \
 144           loadsegment(seg, tmp); }
 145
 146         GET_SEG(gs);
 147         COPY_SEG(fs);
 148         COPY_SEG(es);
 149         COPY_SEG(ds);
 150         COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
 151         COPY(dx); COPY(cx); COPY(ip);
 152         COPY_SEG_STRICT(cs);
 153         COPY_SEG_STRICT(ss);
 154
 155         {
 156                 unsigned int tmpflags;
 157
 158                 err |= __get_user(tmpflags, &sc->flags);
 159                 regs->flags = (regs->flags & ~FIX_EFLAGS) |
 160                                                 (tmpflags & FIX_EFLAGS);
 161                 regs->orig_ax = -1;             /* disable syscall checks */
 162         }
 163
 164         {
 165                 void __user *buf;
 166
 167                 err |= __get_user(buf, &sc->fpstate);
 168                 err |= restore_i387_xstate(buf);
 169         }
 170
 171         err |= __get_user(*pax, &sc->ax);
 172         return err;
 173 }
 174
 175 asmlinkage unsigned long sys_sigreturn(unsigned long __unused)
 176 {
 177         struct sigframe __user *frame;
 178         struct pt_regs *regs;
 179         unsigned long ax;
 180         sigset_t set;
 181
 182         regs = (struct pt_regs *) &__unused;
 183         frame = (struct sigframe __user *)(regs->sp - 8);
 184
 185         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 186                 goto badframe;
 187         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 188                 && __copy_from_user(&set.sig[1], &frame->extramask,
 189                                     sizeof(frame->extramask))))
 190                 goto badframe;
 191
 192         sigdelsetmask(&set, ~_BLOCKABLE);
 193         spin_lock_irq(&current->sighand->siglock);
 194         current->blocked = set;
 195         recalc_sigpending();
 196         spin_unlock_irq(&current->sighand->siglock);
 197
 198         if (restore_sigcontext(regs, &frame->sc, &ax))
 199                 goto badframe;
 200         return ax;
 201
 202 badframe:
 203         if (show_unhandled_signals && printk_ratelimit()) {
 204                 printk("%s%s[%d] bad frame in sigreturn frame:"
 205                         "%p ip:%lx sp:%lx oeax:%lx",
 206                     task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 207                     current->comm, task_pid_nr(current), frame, regs->ip,
 208                     regs->sp, regs->orig_ax);
 209                 print_vma_addr(" in ", regs->ip);
 210                 printk(KERN_CONT "\n");
 211         }
 212
 213         force_sig(SIGSEGV, current);
 214
 215         return 0;
 216 }
 217
 218 asmlinkage int sys_rt_sigreturn(unsigned long __unused)
 219 {
 220         struct pt_regs *regs = (struct pt_regs *)&__unused;
 221         struct rt_sigframe __user *frame;
 222         unsigned long ax;
 223         sigset_t set;
 224
 225         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 226         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 227                 goto badframe;
 228         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 229                 goto badframe;
 230
 231         sigdelsetmask(&set, ~_BLOCKABLE);
 232         spin_lock_irq(&current->sighand->siglock);
 233         current->blocked = set;
 234         recalc_sigpending();
 235         spin_unlock_irq(&current->sighand->siglock);
 236
 237         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 238                 goto badframe;
 239
 240         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 241                 goto badframe;
 242
 243         return ax;
 244
 245 badframe:
 246         signal_fault(regs, frame, "rt sigreturn");
 247         return 0;
 248 }
 249
 250 /*
 251  * Set up a signal frame.
 252  */
 253 static int
 254 setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 255                  struct pt_regs *regs, unsigned long mask)
 256 {
 257         int tmp, err = 0;
 258
 259         err |= __put_user(regs->fs, (unsigned int __user *)&sc->fs);
 260         savesegment(gs, tmp);
 261         err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
 262
 263         err |= __put_user(regs->es, (unsigned int __user *)&sc->es);
 264         err |= __put_user(regs->ds, (unsigned int __user *)&sc->ds);
 265         err |= __put_user(regs->di, &sc->di);
 266         err |= __put_user(regs->si, &sc->si);
 267         err |= __put_user(regs->bp, &sc->bp);
 268         err |= __put_user(regs->sp, &sc->sp);
 269         err |= __put_user(regs->bx, &sc->bx);
 270         err |= __put_user(regs->dx, &sc->dx);
 271         err |= __put_user(regs->cx, &sc->cx);
 272         err |= __put_user(regs->ax, &sc->ax);
 273         err |= __put_user(current->thread.trap_no, &sc->trapno);
 274         err |= __put_user(current->thread.error_code, &sc->err);
 275         err |= __put_user(regs->ip, &sc->ip);
 276         err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
 277         err |= __put_user(regs->flags, &sc->flags);
 278         err |= __put_user(regs->sp, &sc->sp_at_signal);
 279         err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
 280
 281         tmp = save_i387_xstate(fpstate);
 282         if (tmp < 0)
 283                 err = 1;
 284         else
 285                 err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
 286
 287         /* non-iBCS2 extensions.. */
 288         err |= __put_user(mask, &sc->oldmask);
 289         err |= __put_user(current->thread.cr2, &sc->cr2);
 290
 291         return err;
 292 }
 293
 294 /*
 295  * Determine which stack to use..
 296  */
 297 static inline void __user *
 298 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 299              void **fpstate)
 300 {
 301         unsigned long sp;
 302
 303         /* Default to using normal stack */
 304         sp = regs->sp;
 305
 306         /*
 307          * If we are on the alternate signal stack and would overflow it, don't.
 308          * Return an always-bogus address instead so we will die with SIGSEGV.
 309          */
 310         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
 311                 return (void __user *) -1L;
 312
 313         /* This is the X/Open sanctioned signal stack switching.  */
 314         if (ka->sa.sa_flags & SA_ONSTACK) {
 315                 if (sas_ss_flags(sp) == 0)
 316                         sp = current->sas_ss_sp + current->sas_ss_size;
 317         } else {
 318                 /* This is the legacy signal stack switching. */
 319                 if ((regs->ss & 0xffff) != __USER_DS &&
 320                         !(ka->sa.sa_flags & SA_RESTORER) &&
 321                                 ka->sa.sa_restorer)
 322                         sp = (unsigned long) ka->sa.sa_restorer;
 323         }
 324
 325         if (used_math()) {
 326                 sp = sp - sig_xstate_size;
 327                 *fpstate = (struct _fpstate *) sp;
 328         }
 329
 330         sp -= frame_size;
 331         /*
 332          * Align the stack pointer according to the i386 ABI,
 333          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 334          */
 335         sp = ((sp + 4) & -16ul) - 4;
 336
 337         return (void __user *) sp;
 338 }
 339
 340 static int
 341 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 342               struct pt_regs *regs)
 343 {
 344         struct sigframe __user *frame;
 345         void __user *restorer;
 346         int err = 0;
 347         void __user *fpstate = NULL;
 348
 349         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 350
 351         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 352                 return -EFAULT;
 353
 354         err = __put_user(sig, &frame->sig);
 355         if (err)
 356                 return -EFAULT;
 357
 358         err = setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]);
 359         if (err)
 360                 return -EFAULT;
 361
 362         if (_NSIG_WORDS > 1) {
 363                 err = __copy_to_user(&frame->extramask, &set->sig[1],
 364                                       sizeof(frame->extramask));
 365                 if (err)
 366                         return -EFAULT;
 367         }
 368
 369         if (current->mm->context.vdso)
 370                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 371         else
 372                 restorer = &frame->retcode;
 373         if (ka->sa.sa_flags & SA_RESTORER)
 374                 restorer = ka->sa.sa_restorer;
 375
 376         /* Set up to return from userspace.  */
 377         err |= __put_user(restorer, &frame->pretcode);
 378
 379         /*
 380          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 381          *
 382          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 383          * reasons and because gdb uses it as a signature to notice
 384          * signal handler stack frames.
 385          */
 386         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
 387         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
 388         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
 389
 390         if (err)
 391                 return -EFAULT;
 392
 393         /* Set up registers for signal handler */
 394         regs->sp = (unsigned long)frame;
 395         regs->ip = (unsigned long)ka->sa.sa_handler;
 396         regs->ax = (unsigned long)sig;
 397         regs->dx = 0;
 398         regs->cx = 0;
 399
 400         regs->ds = __USER_DS;
 401         regs->es = __USER_DS;
 402         regs->ss = __USER_DS;
 403         regs->cs = __USER_CS;
 404
 405         return 0;
 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         struct rt_sigframe __user *frame;
 412         void __user *restorer;
 413         int err = 0;
 414         void __user *fpstate = NULL;
 415
 416         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 417
 418         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 419                 return -EFAULT;
 420
 421         err |= __put_user(sig, &frame->sig);
 422         err |= __put_user(&frame->info, &frame->pinfo);
 423         err |= __put_user(&frame->uc, &frame->puc);
 424         err |= copy_siginfo_to_user(&frame->info, info);
 425         if (err)
 426                 return -EFAULT;
 427
 428         /* Create the ucontext.  */
 429         if (cpu_has_xsave)
 430                 err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
 431         else
 432                 err |= __put_user(0, &frame->uc.uc_flags);
 433         err |= __put_user(0, &frame->uc.uc_link);
 434         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 435         err |= __put_user(sas_ss_flags(regs->sp),
 436                           &frame->uc.uc_stack.ss_flags);
 437         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 438         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 439                                 regs, set->sig[0]);
 440         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 441         if (err)
 442                 return -EFAULT;
 443
 444         /* Set up to return from userspace.  */
 445         restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 446         if (ka->sa.sa_flags & SA_RESTORER)
 447                 restorer = ka->sa.sa_restorer;
 448         err |= __put_user(restorer, &frame->pretcode);
 449
 450         /*
 451          * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 452          *
 453          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 454          * reasons and because gdb uses it as a signature to notice
 455          * signal handler stack frames.
 456          */
 457         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
 458         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
 459         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
 460
 461         if (err)
 462                 return -EFAULT;
 463
 464         /* Set up registers for signal handler */
 465         regs->sp = (unsigned long)frame;
 466         regs->ip = (unsigned long)ka->sa.sa_handler;
 467         regs->ax = (unsigned long)sig;
 468         regs->dx = (unsigned long)&frame->info;
 469         regs->cx = (unsigned long)&frame->uc;
 470
 471         regs->ds = __USER_DS;
 472         regs->es = __USER_DS;
 473         regs->ss = __USER_DS;
 474         regs->cs = __USER_CS;
 475
 476         return 0;
 477 }
 478
 479 /*
 480  * OK, we're invoking a handler:
 481  */
 482 static int
 483 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 484                sigset_t *set, struct pt_regs *regs)
 485 {
 486         int ret;
 487         int usig;
 488
 489         usig = current_thread_info()->exec_domain
 490                 && current_thread_info()->exec_domain->signal_invmap
 491                 && sig < 32
 492                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 493                 : sig;
 494
 495         /* Set up the stack frame */
 496         if (ka->sa.sa_flags & SA_SIGINFO)
 497                 ret = __setup_rt_frame(usig, ka, info, set, regs);
 498         else
 499                 ret = __setup_frame(usig, ka, set, regs);
 500
 501         if (ret) {
 502                 force_sigsegv(sig, current);
 503                 return -EFAULT;
 504         }
 505
 506         return ret;
 507 }
 508
 509 static int
 510 handle_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 (syscall_get_nr(current, regs) >= 0) {
 517                 /* If so, check system call restarting.. */
 518                 switch (syscall_get_error(current, regs)) {
 519                 case -ERESTART_RESTARTBLOCK:
 520                 case -ERESTARTNOHAND:
 521                         regs->ax = -EINTR;
 522                         break;
 523
 524                 case -ERESTARTSYS:
 525                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 526                                 regs->ax = -EINTR;
 527                                 break;
 528                         }
 529                 /* fallthrough */
 530                 case -ERESTARTNOINTR:
 531                         regs->ax = regs->orig_ax;
 532                         regs->ip -= 2;
 533                         break;
 534                 }
 535         }
 536
 537         /*
 538          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 539          * flag so that register information in the sigcontext is correct.
 540          */
 541         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 542             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 543                 regs->flags &= ~X86_EFLAGS_TF;
 544
 545         ret = setup_rt_frame(sig, ka, info, oldset, regs);
 546
 547         if (ret)
 548                 return ret;
 549
 550         /*
 551          * Clear the direction flag as per the ABI for function entry.
 552          */
 553         regs->flags &= ~X86_EFLAGS_DF;
 554
 555         /*
 556          * Clear TF when entering the signal handler, but
 557          * notify any tracer that was single-stepping it.
 558          * The tracer may want to single-step inside the
 559          * handler too.
 560          */
 561         regs->flags &= ~X86_EFLAGS_TF;
 562
 563         spin_lock_irq(&current->sighand->siglock);
 564         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 565         if (!(ka->sa.sa_flags & SA_NODEFER))
 566                 sigaddset(&current->blocked, sig);
 567         recalc_sigpending();
 568         spin_unlock_irq(&current->sighand->siglock);
 569
 570         tracehook_signal_handler(sig, info, ka, regs,
 571                                  test_thread_flag(TIF_SINGLESTEP));
 572
 573         return 0;
 574 }
 575
 576 #define NR_restart_syscall      __NR_restart_syscall
 577 /*
 578  * Note that 'init' is a special process: it doesn't get signals it doesn't
 579  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 580  * mistake.
 581  */
 582 static void do_signal(struct pt_regs *regs)
 583 {
 584         struct k_sigaction ka;
 585         siginfo_t info;
 586         int signr;
 587         sigset_t *oldset;
 588
 589         /*
 590          * We want the common case to go fast, which is why we may in certain
 591          * cases get here from kernel mode. Just return without doing anything
 592          * if so.
 593          * X86_32: vm86 regs switched out by assembly code before reaching
 594          * here, so testing against kernel CS suffices.
 595          */
 596         if (!user_mode(regs))
 597                 return;
 598
 599         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 600                 oldset = &current->saved_sigmask;
 601         else
 602                 oldset = &current->blocked;
 603
 604         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 605         if (signr > 0) {
 606                 /*
 607                  * Re-enable any watchpoints before delivering the
 608                  * signal to user space. The processor register will
 609                  * have been cleared if the watchpoint triggered
 610                  * inside the kernel.
 611                  */
 612                 if (current->thread.debugreg7)
 613                         set_debugreg(current->thread.debugreg7, 7);
 614
 615                 /* Whee! Actually deliver the signal.  */
 616                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 617                         /*
 618                          * A signal was successfully delivered; the saved
 619                          * sigmask will have been stored in the signal frame,
 620                          * and will be restored by sigreturn, so we can simply
 621                          * clear the TS_RESTORE_SIGMASK flag.
 622                          */
 623                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 624                 }
 625                 return;
 626         }
 627
 628         /* Did we come from a system call? */
 629         if (syscall_get_nr(current, regs) >= 0) {
 630                 /* Restart the system call - no handlers present */
 631                 switch (syscall_get_error(current, regs)) {
 632                 case -ERESTARTNOHAND:
 633                 case -ERESTARTSYS:
 634                 case -ERESTARTNOINTR:
 635                         regs->ax = regs->orig_ax;
 636                         regs->ip -= 2;
 637                         break;
 638
 639                 case -ERESTART_RESTARTBLOCK:
 640                         regs->ax = NR_restart_syscall;
 641                         regs->ip -= 2;
 642                         break;
 643                 }
 644         }
 645
 646         /*
 647          * If there's no signal to deliver, we just put the saved sigmask
 648          * back.
 649          */
 650         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 651                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 652                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 653         }
 654 }
 655
 656 /*
 657  * notification of userspace execution resumption
 658  * - triggered by the TIF_WORK_MASK flags
 659  */
 660 void
 661 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 662 {
 663         /* deal with pending signal delivery */
 664         if (thread_info_flags & _TIF_SIGPENDING)
 665                 do_signal(regs);
 666
 667         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 668                 clear_thread_flag(TIF_NOTIFY_RESUME);
 669                 tracehook_notify_resume(regs);
 670         }
 671
 672         clear_thread_flag(TIF_IRET);
 673 }
 674
 675 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 676 {
 677         struct task_struct *me = current;
 678
 679         if (show_unhandled_signals && printk_ratelimit()) {
 680                 printk(KERN_INFO
 681                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 682                        me->comm, me->pid, where, frame,
 683                        regs->ip, regs->sp, regs->orig_ax);
 684                 print_vma_addr(" in ", regs->ip);
 685                 printk(KERN_CONT "\n");
 686         }
 687
 688         force_sig(SIGSEGV, me);
 689 }