arch/ia64/kernel/signal.c

   1 /*
   2  * Architecture-specific signal handling support.
   3  *
   4  * Copyright (C) 1999-2004 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * Derived from i386 and Alpha versions.
   8  */
   9
  10 #include <linux/errno.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mm.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/tracehook.h>
  15 #include <linux/sched.h>
  16 #include <linux/signal.h>
  17 #include <linux/smp.h>
  18 #include <linux/stddef.h>
  19 #include <linux/tty.h>
  20 #include <linux/binfmts.h>
  21 #include <linux/unistd.h>
  22 #include <linux/wait.h>
  23
  24 #include <asm/intrinsics.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/rse.h>
  27 #include <asm/sigcontext.h>
  28
  29 #include "sigframe.h"
  30
  31 #define DEBUG_SIG       0
  32 #define STACK_ALIGN     16              /* minimal alignment for stack pointer */
  33 #define _BLOCKABLE      (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  34
  35 #if _NSIG_WORDS > 1
  36 # define PUT_SIGSET(k,u)        __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
  37 # define GET_SIGSET(k,u)        __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
  38 #else
  39 # define PUT_SIGSET(k,u)        __put_user((k)->sig[0], &(u)->sig[0])
  40 # define GET_SIGSET(k,u)        __get_user((k)->sig[0], &(u)->sig[0])
  41 #endif
  42
  43 asmlinkage long
  44 sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
  45                  long arg3, long arg4, long arg5, long arg6, long arg7,
  46                  struct pt_regs regs)
  47 {
  48         return do_sigaltstack(uss, uoss, regs.r12);
  49 }
  50
  51 static long
  52 restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
  53 {
  54         unsigned long ip, flags, nat, um, cfm, rsc;
  55         long err;
  56
  57         /* Always make any pending restarted system calls return -EINTR */
  58         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  59
  60         /* restore scratch that always needs gets updated during signal delivery: */
  61         err  = __get_user(flags, &sc->sc_flags);
  62         err |= __get_user(nat, &sc->sc_nat);
  63         err |= __get_user(ip, &sc->sc_ip);                      /* instruction pointer */
  64         err |= __get_user(cfm, &sc->sc_cfm);
  65         err |= __get_user(um, &sc->sc_um);                      /* user mask */
  66         err |= __get_user(rsc, &sc->sc_ar_rsc);
  67         err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
  68         err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
  69         err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
  70         err |= __get_user(scr->pt.pr, &sc->sc_pr);              /* predicates */
  71         err |= __get_user(scr->pt.b0, &sc->sc_br[0]);           /* b0 (rp) */
  72         err |= __get_user(scr->pt.b6, &sc->sc_br[6]);           /* b6 */
  73         err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
  74         err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8);       /* r8-r11 */
  75         err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8);     /* r12-r13 */
  76         err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8);       /* r15 */
  77
  78         scr->pt.cr_ifs = cfm | (1UL << 63);
  79         scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
  80
  81         /* establish new instruction pointer: */
  82         scr->pt.cr_iip = ip & ~0x3UL;
  83         ia64_psr(&scr->pt)->ri = ip & 0x3;
  84         scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
  85
  86         scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
  87
  88         if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
  89                 /* Restore most scratch-state only when not in syscall. */
  90                 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);              /* ar.ccv */
  91                 err |= __get_user(scr->pt.b7, &sc->sc_br[7]);                   /* b7 */
  92                 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]);                 /* r14 */
  93                 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
  94                 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8);       /* r2-r3 */
  95                 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8);    /* r16-r31 */
  96         }
  97
  98         if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
  99                 struct ia64_psr *psr = ia64_psr(&scr->pt);
 100
 101                 err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
 102                 psr->mfh = 0;   /* drop signal handler's fph contents... */
 103                 preempt_disable();
 104                 if (psr->dfh)
 105                         ia64_drop_fpu(current);
 106                 else {
 107                         /* We already own the local fph, otherwise psr->dfh wouldn't be 0.  */
 108                         __ia64_load_fpu(current->thread.fph);
 109                         ia64_set_local_fpu_owner(current);
 110                 }
 111                 preempt_enable();
 112         }
 113         return err;
 114 }
 115
 116 int
 117 copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
 118 {
 119         if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
 120                 return -EFAULT;
 121         if (from->si_code < 0) {
 122                 if (__copy_to_user(to, from, sizeof(siginfo_t)))
 123                         return -EFAULT;
 124                 return 0;
 125         } else {
 126                 int err;
 127
 128                 /*
 129                  * If you change siginfo_t structure, please be sure this code is fixed
 130                  * accordingly.  It should never copy any pad contained in the structure
 131                  * to avoid security leaks, but must copy the generic 3 ints plus the
 132                  * relevant union member.
 133                  */
 134                 err = __put_user(from->si_signo, &to->si_signo);
 135                 err |= __put_user(from->si_errno, &to->si_errno);
 136                 err |= __put_user((short)from->si_code, &to->si_code);
 137                 switch (from->si_code >> 16) {
 138                       case __SI_FAULT >> 16:
 139                         err |= __put_user(from->si_flags, &to->si_flags);
 140                         err |= __put_user(from->si_isr, &to->si_isr);
 141                       case __SI_POLL >> 16:
 142                         err |= __put_user(from->si_addr, &to->si_addr);
 143                         err |= __put_user(from->si_imm, &to->si_imm);
 144                         break;
 145                       case __SI_TIMER >> 16:
 146                         err |= __put_user(from->si_tid, &to->si_tid);
 147                         err |= __put_user(from->si_overrun, &to->si_overrun);
 148                         err |= __put_user(from->si_ptr, &to->si_ptr);
 149                         break;
 150                       case __SI_RT >> 16:       /* Not generated by the kernel as of now.  */
 151                       case __SI_MESGQ >> 16:
 152                         err |= __put_user(from->si_uid, &to->si_uid);
 153                         err |= __put_user(from->si_pid, &to->si_pid);
 154                         err |= __put_user(from->si_ptr, &to->si_ptr);
 155                         break;
 156                       case __SI_CHLD >> 16:
 157                         err |= __put_user(from->si_utime, &to->si_utime);
 158                         err |= __put_user(from->si_stime, &to->si_stime);
 159                         err |= __put_user(from->si_status, &to->si_status);
 160                       default:
 161                         err |= __put_user(from->si_uid, &to->si_uid);
 162                         err |= __put_user(from->si_pid, &to->si_pid);
 163                         break;
 164                 }
 165                 return err;
 166         }
 167 }
 168
 169 long
 170 ia64_rt_sigreturn (struct sigscratch *scr)
 171 {
 172         extern char ia64_strace_leave_kernel, ia64_leave_kernel;
 173         struct sigcontext __user *sc;
 174         struct siginfo si;
 175         sigset_t set;
 176         long retval;
 177
 178         sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
 179
 180         /*
 181          * When we return to the previously executing context, r8 and r10 have already
 182          * been setup the way we want them.  Indeed, if the signal wasn't delivered while
 183          * in a system call, we must not touch r8 or r10 as otherwise user-level state
 184          * could be corrupted.
 185          */
 186         retval = (long) &ia64_leave_kernel;
 187         if (test_thread_flag(TIF_SYSCALL_TRACE)
 188             || test_thread_flag(TIF_SYSCALL_AUDIT))
 189                 /*
 190                  * strace expects to be notified after sigreturn returns even though the
 191                  * context to which we return may not be in the middle of a syscall.
 192                  * Thus, the return-value that strace displays for sigreturn is
 193                  * meaningless.
 194                  */
 195                 retval = (long) &ia64_strace_leave_kernel;
 196
 197         if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
 198                 goto give_sigsegv;
 199
 200         if (GET_SIGSET(&set, &sc->sc_mask))
 201                 goto give_sigsegv;
 202
 203         sigdelsetmask(&set, ~_BLOCKABLE);
 204
 205         spin_lock_irq(&current->sighand->siglock);
 206         {
 207                 current->blocked = set;
 208                 recalc_sigpending();
 209         }
 210         spin_unlock_irq(&current->sighand->siglock);
 211
 212         if (restore_sigcontext(sc, scr))
 213                 goto give_sigsegv;
 214
 215 #if DEBUG_SIG
 216         printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
 217                current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
 218 #endif
 219         /*
 220          * It is more difficult to avoid calling this function than to
 221          * call it and ignore errors.
 222          */
 223         do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
 224         return retval;
 225
 226   give_sigsegv:
 227         si.si_signo = SIGSEGV;
 228         si.si_errno = 0;
 229         si.si_code = SI_KERNEL;
 230         si.si_pid = task_pid_vnr(current);
 231         si.si_uid = current_uid();
 232         si.si_addr = sc;
 233         force_sig_info(SIGSEGV, &si, current);
 234         return retval;
 235 }
 236
 237 /*
 238  * This does just the minimum required setup of sigcontext.
 239  * Specifically, it only installs data that is either not knowable at
 240  * the user-level or that gets modified before execution in the
 241  * trampoline starts.  Everything else is done at the user-level.
 242  */
 243 static long
 244 setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
 245 {
 246         unsigned long flags = 0, ifs, cfm, nat;
 247         long err = 0;
 248
 249         ifs = scr->pt.cr_ifs;
 250
 251         if (on_sig_stack((unsigned long) sc))
 252                 flags |= IA64_SC_FLAG_ONSTACK;
 253         if ((ifs & (1UL << 63)) == 0)
 254                 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
 255                 flags |= IA64_SC_FLAG_IN_SYSCALL;
 256         cfm = ifs & ((1UL << 38) - 1);
 257         ia64_flush_fph(current);
 258         if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
 259                 flags |= IA64_SC_FLAG_FPH_VALID;
 260                 err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
 261         }
 262
 263         nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
 264
 265         err |= __put_user(flags, &sc->sc_flags);
 266         err |= __put_user(nat, &sc->sc_nat);
 267         err |= PUT_SIGSET(mask, &sc->sc_mask);
 268         err |= __put_user(cfm, &sc->sc_cfm);
 269         err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
 270         err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
 271         err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat);            /* ar.unat */
 272         err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);            /* ar.fpsr */
 273         err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
 274         err |= __put_user(scr->pt.pr, &sc->sc_pr);                      /* predicates */
 275         err |= __put_user(scr->pt.b0, &sc->sc_br[0]);                   /* b0 (rp) */
 276         err |= __put_user(scr->pt.b6, &sc->sc_br[6]);                   /* b6 */
 277         err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8);           /* r1 */
 278         err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8);         /* r8-r11 */
 279         err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8);       /* r12-r13 */
 280         err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8);         /* r15 */
 281         err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
 282
 283         if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
 284                 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
 285                 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);              /* ar.ccv */
 286                 err |= __put_user(scr->pt.b7, &sc->sc_br[7]);                   /* b7 */
 287                 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]);                 /* r14 */
 288                 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
 289                 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8);         /* r2-r3 */
 290                 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8);      /* r16-r31 */
 291         }
 292         return err;
 293 }
 294
 295 /*
 296  * Check whether the register-backing store is already on the signal stack.
 297  */
 298 static inline int
 299 rbs_on_sig_stack (unsigned long bsp)
 300 {
 301         return (bsp - current->sas_ss_sp < current->sas_ss_size);
 302 }
 303
 304 static long
 305 force_sigsegv_info (int sig, void __user *addr)
 306 {
 307         unsigned long flags;
 308         struct siginfo si;
 309
 310         if (sig == SIGSEGV) {
 311                 /*
 312                  * Acquiring siglock around the sa_handler-update is almost
 313                  * certainly overkill, but this isn't a
 314                  * performance-critical path and I'd rather play it safe
 315                  * here than having to debug a nasty race if and when
 316                  * something changes in kernel/signal.c that would make it
 317                  * no longer safe to modify sa_handler without holding the
 318                  * lock.
 319                  */
 320                 spin_lock_irqsave(&current->sighand->siglock, flags);
 321                 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
 322                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 323         }
 324         si.si_signo = SIGSEGV;
 325         si.si_errno = 0;
 326         si.si_code = SI_KERNEL;
 327         si.si_pid = task_pid_vnr(current);
 328         si.si_uid = current_uid();
 329         si.si_addr = addr;
 330         force_sig_info(SIGSEGV, &si, current);
 331         return 0;
 332 }
 333
 334 static long
 335 setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
 336              struct sigscratch *scr)
 337 {
 338         extern char __kernel_sigtramp[];
 339         unsigned long tramp_addr, new_rbs = 0, new_sp;
 340         struct sigframe __user *frame;
 341         long err;
 342
 343         new_sp = scr->pt.r12;
 344         tramp_addr = (unsigned long) __kernel_sigtramp;
 345         if (ka->sa.sa_flags & SA_ONSTACK) {
 346                 int onstack = sas_ss_flags(new_sp);
 347
 348                 if (onstack == 0) {
 349                         new_sp = current->sas_ss_sp + current->sas_ss_size;
 350                         /*
 351                          * We need to check for the register stack being on the
 352                          * signal stack separately, because it's switched
 353                          * separately (memory stack is switched in the kernel,
 354                          * register stack is switched in the signal trampoline).
 355                          */
 356                         if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
 357                                 new_rbs = ALIGN(current->sas_ss_sp,
 358                                                 sizeof(long));
 359                 } else if (onstack == SS_ONSTACK) {
 360                         unsigned long check_sp;
 361
 362                         /*
 363                          * If we are on the alternate signal stack and would
 364                          * overflow it, don't. Return an always-bogus address
 365                          * instead so we will die with SIGSEGV.
 366                          */
 367                         check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
 368                         if (!likely(on_sig_stack(check_sp)))
 369                                 return force_sigsegv_info(sig, (void __user *)
 370                                                           check_sp);
 371                 }
 372         }
 373         frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
 374
 375         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 376                 return force_sigsegv_info(sig, frame);
 377
 378         err  = __put_user(sig, &frame->arg0);
 379         err |= __put_user(&frame->info, &frame->arg1);
 380         err |= __put_user(&frame->sc, &frame->arg2);
 381         err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
 382         err |= __put_user(0, &frame->sc.sc_loadrs);     /* initialize to zero */
 383         err |= __put_user(ka->sa.sa_handler, &frame->handler);
 384
 385         err |= copy_siginfo_to_user(&frame->info, info);
 386
 387         err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
 388         err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
 389         err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
 390         err |= setup_sigcontext(&frame->sc, set, scr);
 391
 392         if (unlikely(err))
 393                 return force_sigsegv_info(sig, frame);
 394
 395         scr->pt.r12 = (unsigned long) frame - 16;       /* new stack pointer */
 396         scr->pt.ar_fpsr = FPSR_DEFAULT;                 /* reset fpsr for signal handler */
 397         scr->pt.cr_iip = tramp_addr;
 398         ia64_psr(&scr->pt)->ri = 0;                     /* start executing in first slot */
 399         ia64_psr(&scr->pt)->be = 0;                     /* force little-endian byte-order */
 400         /*
 401          * Force the interruption function mask to zero.  This has no effect when a
 402          * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
 403          * ignored), but it has the desirable effect of making it possible to deliver a
 404          * signal with an incomplete register frame (which happens when a mandatory RSE
 405          * load faults).  Furthermore, it has no negative effect on the getting the user's
 406          * dirty partition preserved, because that's governed by scr->pt.loadrs.
 407          */
 408         scr->pt.cr_ifs = (1UL << 63);
 409
 410         /*
 411          * Note: this affects only the NaT bits of the scratch regs (the ones saved in
 412          * pt_regs), which is exactly what we want.
 413          */
 414         scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
 415
 416 #if DEBUG_SIG
 417         printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
 418                current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
 419 #endif
 420         return 1;
 421 }
 422
 423 static long
 424 handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
 425                struct sigscratch *scr)
 426 {
 427         if (!setup_frame(sig, ka, info, oldset, scr))
 428                 return 0;
 429
 430         spin_lock_irq(&current->sighand->siglock);
 431         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 432         if (!(ka->sa.sa_flags & SA_NODEFER))
 433                 sigaddset(&current->blocked, sig);
 434         recalc_sigpending();
 435         spin_unlock_irq(&current->sighand->siglock);
 436
 437         /*
 438          * Let tracing know that we've done the handler setup.
 439          */
 440         tracehook_signal_handler(sig, info, ka, &scr->pt,
 441                                  test_thread_flag(TIF_SINGLESTEP));
 442
 443         return 1;
 444 }
 445
 446 /*
 447  * Note that `init' is a special process: it doesn't get signals it doesn't want to
 448  * handle.  Thus you cannot kill init even with a SIGKILL even by mistake.
 449  */
 450 void
 451 ia64_do_signal (struct sigscratch *scr, long in_syscall)
 452 {
 453         struct k_sigaction ka;
 454         sigset_t *oldset;
 455         siginfo_t info;
 456         long restart = in_syscall;
 457         long errno = scr->pt.r8;
 458
 459         /*
 460          * In the ia64_leave_kernel code path, we want the common case to go fast, which
 461          * is why we may in certain cases get here from kernel mode. Just return without
 462          * doing anything if so.
 463          */
 464         if (!user_mode(&scr->pt))
 465                 return;
 466
 467         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 468                 oldset = &current->saved_sigmask;
 469         else
 470                 oldset = &current->blocked;
 471
 472         /*
 473          * This only loops in the rare cases of handle_signal() failing, in which case we
 474          * need to push through a forced SIGSEGV.
 475          */
 476         while (1) {
 477                 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
 478
 479                 /*
 480                  * get_signal_to_deliver() may have run a debugger (via notify_parent())
 481                  * and the debugger may have modified the state (e.g., to arrange for an
 482                  * inferior call), thus it's important to check for restarting _after_
 483                  * get_signal_to_deliver().
 484                  */
 485                 if ((long) scr->pt.r10 != -1)
 486                         /*
 487                          * A system calls has to be restarted only if one of the error codes
 488                          * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned.  If r10
 489                          * isn't -1 then r8 doesn't hold an error code and we don't need to
 490                          * restart the syscall, so we can clear the "restart" flag here.
 491                          */
 492                         restart = 0;
 493
 494                 if (signr <= 0)
 495                         break;
 496
 497                 if (unlikely(restart)) {
 498                         switch (errno) {
 499                               case ERESTART_RESTARTBLOCK:
 500                               case ERESTARTNOHAND:
 501                                 scr->pt.r8 = EINTR;
 502                                 /* note: scr->pt.r10 is already -1 */
 503                                 break;
 504
 505                               case ERESTARTSYS:
 506                                 if ((ka.sa.sa_flags & SA_RESTART) == 0) {
 507                                         scr->pt.r8 = EINTR;
 508                                         /* note: scr->pt.r10 is already -1 */
 509                                         break;
 510                                 }
 511                               case ERESTARTNOINTR:
 512                                 ia64_decrement_ip(&scr->pt);
 513                                 restart = 0; /* don't restart twice if handle_signal() fails... */
 514                         }
 515                 }
 516
 517                 /*
 518                  * Whee!  Actually deliver the signal.  If the delivery failed, we need to
 519                  * continue to iterate in this loop so we can deliver the SIGSEGV...
 520                  */
 521                 if (handle_signal(signr, &ka, &info, oldset, scr)) {
 522                         /*
 523                          * A signal was successfully delivered; the saved
 524                          * sigmask will have been stored in the signal frame,
 525                          * and will be restored by sigreturn, so we can simply
 526                          * clear the TS_RESTORE_SIGMASK flag.
 527                          */
 528                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 529                         return;
 530                 }
 531         }
 532
 533         /* Did we come from a system call? */
 534         if (restart) {
 535                 /* Restart the system call - no handlers present */
 536                 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
 537                     || errno == ERESTART_RESTARTBLOCK)
 538                 {
 539                         /*
 540                          * Note: the syscall number is in r15 which is saved in
 541                          * pt_regs so all we need to do here is adjust ip so that
 542                          * the "break" instruction gets re-executed.
 543                          */
 544                         ia64_decrement_ip(&scr->pt);
 545                         if (errno == ERESTART_RESTARTBLOCK)
 546                                 scr->pt.r15 = __NR_restart_syscall;
 547                 }
 548         }
 549
 550         /* if there's no signal to deliver, we just put the saved sigmask
 551          * back */
 552         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 553                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 554                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 555         }
 556 }