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/ia32.h>
  25 #include <asm/intrinsics.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/rse.h>
  28 #include <asm/sigcontext.h>
  29
  30 #include "sigframe.h"
  31
  32 #define DEBUG_SIG       0
  33 #define STACK_ALIGN     16              /* minimal alignment for stack pointer */
  34 #define _BLOCKABLE      (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  35
  36 #if _NSIG_WORDS > 1
  37 # define PUT_SIGSET(k,u)        __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
  38 # define GET_SIGSET(k,u)        __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
  39 #else
  40 # define PUT_SIGSET(k,u)        __put_user((k)->sig[0], &(u)->sig[0])
  41 # define GET_SIGSET(k,u)        __get_user((k)->sig[0], &(u)->sig[0])
  42 #endif
  43
  44 asmlinkage long
  45 sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
  46                  long arg3, long arg4, long arg5, long arg6, long arg7,
  47                  struct pt_regs regs)
  48 {
  49         return do_sigaltstack(uss, uoss, regs.r12);
  50 }
  51
  52 static long
  53 restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
  54 {
  55         unsigned long ip, flags, nat, um, cfm, rsc;
  56         long err;
  57
  58         /* Always make any pending restarted system calls return -EINTR */
  59         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  60
  61         /* restore scratch that always needs gets updated during signal delivery: */
  62         err  = __get_user(flags, &sc->sc_flags);
  63         err |= __get_user(nat, &sc->sc_nat);
  64         err |= __get_user(ip, &sc->sc_ip);                      /* instruction pointer */
  65         err |= __get_user(cfm, &sc->sc_cfm);
  66         err |= __get_user(um, &sc->sc_um);                      /* user mask */
  67         err |= __get_user(rsc, &sc->sc_ar_rsc);
  68         err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
  69         err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
  70         err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
  71         err |= __get_user(scr->pt.pr, &sc->sc_pr);              /* predicates */
  72         err |= __get_user(scr->pt.b0, &sc->sc_br[0]);           /* b0 (rp) */
  73         err |= __get_user(scr->pt.b6, &sc->sc_br[6]);           /* b6 */
  74         err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
  75         err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8);       /* r8-r11 */
  76         err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8);     /* r12-r13 */
  77         err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8);       /* r15 */
  78
  79         scr->pt.cr_ifs = cfm | (1UL << 63);
  80         scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
  81
  82         /* establish new instruction pointer: */
  83         scr->pt.cr_iip = ip & ~0x3UL;
  84         ia64_psr(&scr->pt)->ri = ip & 0x3;
  85         scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
  86
  87         scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
  88
  89         if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
  90                 /* Restore most scratch-state only when not in syscall. */
  91                 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);              /* ar.ccv */
  92                 err |= __get_user(scr->pt.b7, &sc->sc_br[7]);                   /* b7 */
  93                 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]);                 /* r14 */
  94                 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
  95                 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8);       /* r2-r3 */
  96                 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8);    /* r16-r31 */
  97         }
  98
  99         if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
 100                 struct ia64_psr *psr = ia64_psr(&scr->pt);
 101
 102                 err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
 103                 psr->mfh = 0;   /* drop signal handler's fph contents... */
 104                 preempt_disable();
 105                 if (psr->dfh)
 106                         ia64_drop_fpu(current);
 107                 else {
 108                         /* We already own the local fph, otherwise psr->dfh wouldn't be 0.  */
 109                         __ia64_load_fpu(current->thread.fph);
 110                         ia64_set_local_fpu_owner(current);
 111                 }
 112                 preempt_enable();
 113         }
 114         return err;
 115 }
 116
 117 int
 118 copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
 119 {
 120         if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
 121                 return -EFAULT;
 122         if (from->si_code < 0) {
 123                 if (__copy_to_user(to, from, sizeof(siginfo_t)))
 124                         return -EFAULT;
 125                 return 0;
 126         } else {
 127                 int err;
 128
 129                 /*
 130                  * If you change siginfo_t structure, please be sure this code is fixed
 131                  * accordingly.  It should never copy any pad contained in the structure
 132                  * to avoid security leaks, but must copy the generic 3 ints plus the
 133                  * relevant union member.
 134                  */
 135                 err = __put_user(from->si_signo, &to->si_signo);
 136                 err |= __put_user(from->si_errno, &to->si_errno);
 137                 err |= __put_user((short)from->si_code, &to->si_code);
 138                 switch (from->si_code >> 16) {
 139                       case __SI_FAULT >> 16:
 140                         err |= __put_user(from->si_flags, &to->si_flags);
 141                         err |= __put_user(from->si_isr, &to->si_isr);
 142                       case __SI_POLL >> 16:
 143                         err |= __put_user(from->si_addr, &to->si_addr);
 144                         err |= __put_user(from->si_imm, &to->si_imm);
 145                         break;
 146                       case __SI_TIMER >> 16:
 147                         err |= __put_user(from->si_tid, &to->si_tid);
 148                         err |= __put_user(from->si_overrun, &to->si_overrun);
 149                         err |= __put_user(from->si_ptr, &to->si_ptr);
 150                         break;
 151                       case __SI_RT >> 16:       /* Not generated by the kernel as of now.  */
 152                       case __SI_MESGQ >> 16:
 153                         err |= __put_user(from->si_uid, &to->si_uid);
 154                         err |= __put_user(from->si_pid, &to->si_pid);
 155                         err |= __put_user(from->si_ptr, &to->si_ptr);
 156                         break;
 157                       case __SI_CHLD >> 16:
 158                         err |= __put_user(from->si_utime, &to->si_utime);
 159                         err |= __put_user(from->si_stime, &to->si_stime);
 160                         err |= __put_user(from->si_status, &to->si_status);
 161                       default:
 162                         err |= __put_user(from->si_uid, &to->si_uid);
 163                         err |= __put_user(from->si_pid, &to->si_pid);
 164                         break;
 165                 }
 166                 return err;
 167         }
 168 }
 169
 170 long
 171 ia64_rt_sigreturn (struct sigscratch *scr)
 172 {
 173         extern char ia64_strace_leave_kernel, ia64_leave_kernel;
 174         struct sigcontext __user *sc;
 175         struct siginfo si;
 176         sigset_t set;
 177         long retval;
 178
 179         sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
 180
 181         /*
 182          * When we return to the previously executing context, r8 and r10 have already
 183          * been setup the way we want them.  Indeed, if the signal wasn't delivered while
 184          * in a system call, we must not touch r8 or r10 as otherwise user-level state
 185          * could be corrupted.
 186          */
 187         retval = (long) &ia64_leave_kernel;
 188         if (test_thread_flag(TIF_SYSCALL_TRACE)
 189             || test_thread_flag(TIF_SYSCALL_AUDIT))
 190                 /*
 191                  * strace expects to be notified after sigreturn returns even though the
 192                  * context to which we return may not be in the middle of a syscall.
 193                  * Thus, the return-value that strace displays for sigreturn is
 194                  * meaningless.
 195                  */
 196                 retval = (long) &ia64_strace_leave_kernel;
 197
 198         if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
 199                 goto give_sigsegv;
 200
 201         if (GET_SIGSET(&set, &sc->sc_mask))
 202                 goto give_sigsegv;
 203
 204         sigdelsetmask(&set, ~_BLOCKABLE);
 205
 206         spin_lock_irq(&current->sighand->siglock);
 207         {
 208                 current->blocked = set;
 209                 recalc_sigpending();
 210         }
 211         spin_unlock_irq(&current->sighand->siglock);
 212
 213         if (restore_sigcontext(sc, scr))
 214                 goto give_sigsegv;
 215
 216 #if DEBUG_SIG
 217         printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
 218                current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
 219 #endif
 220         /*
 221          * It is more difficult to avoid calling this function than to
 222          * call it and ignore errors.
 223          */
 224         do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
 225         return retval;
 226
 227   give_sigsegv:
 228         si.si_signo = SIGSEGV;
 229         si.si_errno = 0;
 230         si.si_code = SI_KERNEL;
 231         si.si_pid = task_pid_vnr(current);
 232         si.si_uid = current_uid();
 233         si.si_addr = sc;
 234         force_sig_info(SIGSEGV, &si, current);
 235         return retval;
 236 }
 237
 238 /*
 239  * This does just the minimum required setup of sigcontext.
 240  * Specifically, it only installs data that is either not knowable at
 241  * the user-level or that gets modified before execution in the
 242  * trampoline starts.  Everything else is done at the user-level.
 243  */
 244 static long
 245 setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
 246 {
 247         unsigned long flags = 0, ifs, cfm, nat;
 248         long err = 0;
 249
 250         ifs = scr->pt.cr_ifs;
 251
 252         if (on_sig_stack((unsigned long) sc))
 253                 flags |= IA64_SC_FLAG_ONSTACK;
 254         if ((ifs & (1UL << 63)) == 0)
 255                 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
 256                 flags |= IA64_SC_FLAG_IN_SYSCALL;
 257         cfm = ifs & ((1UL << 38) - 1);
 258         ia64_flush_fph(current);
 259         if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
 260                 flags |= IA64_SC_FLAG_FPH_VALID;
 261                 err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
 262         }
 263
 264         nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
 265
 266         err |= __put_user(flags, &sc->sc_flags);
 267         err |= __put_user(nat, &sc->sc_nat);
 268         err |= PUT_SIGSET(mask, &sc->sc_mask);
 269         err |= __put_user(cfm, &sc->sc_cfm);
 270         err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
 271         err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
 272         err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat);            /* ar.unat */
 273         err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);            /* ar.fpsr */
 274         err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
 275         err |= __put_user(scr->pt.pr, &sc->sc_pr);                      /* predicates */
 276         err |= __put_user(scr->pt.b0, &sc->sc_br[0]);                   /* b0 (rp) */
 277         err |= __put_user(scr->pt.b6, &sc->sc_br[6]);                   /* b6 */
 278         err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8);           /* r1 */
 279         err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8);         /* r8-r11 */
 280         err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8);       /* r12-r13 */
 281         err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8);         /* r15 */
 282         err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
 283
 284         if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
 285                 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
 286                 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);              /* ar.ccv */
 287                 err |= __put_user(scr->pt.b7, &sc->sc_br[7]);                   /* b7 */
 288                 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]);                 /* r14 */
 289                 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
 290                 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8);         /* r2-r3 */
 291                 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8);      /* r16-r31 */
 292         }
 293         return err;
 294 }
 295
 296 /*
 297  * Check whether the register-backing store is already on the signal stack.
 298  */
 299 static inline int
 300 rbs_on_sig_stack (unsigned long bsp)
 301 {
 302         return (bsp - current->sas_ss_sp < current->sas_ss_size);
 303 }
 304
 305 static long
 306 force_sigsegv_info (int sig, void __user *addr)
 307 {
 308         unsigned long flags;
 309         struct siginfo si;
 310
 311         if (sig == SIGSEGV) {
 312                 /*
 313                  * Acquiring siglock around the sa_handler-update is almost
 314                  * certainly overkill, but this isn't a
 315                  * performance-critical path and I'd rather play it safe
 316                  * here than having to debug a nasty race if and when
 317                  * something changes in kernel/signal.c that would make it
 318                  * no longer safe to modify sa_handler without holding the
 319                  * lock.
 320                  */
 321                 spin_lock_irqsave(&current->sighand->siglock, flags);
 322                 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
 323                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 324         }
 325         si.si_signo = SIGSEGV;
 326         si.si_errno = 0;
 327         si.si_code = SI_KERNEL;
 328         si.si_pid = task_pid_vnr(current);
 329         si.si_uid = current_uid();
 330         si.si_addr = addr;
 331         force_sig_info(SIGSEGV, &si, current);
 332         return 0;
 333 }
 334
 335 static long
 336 setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
 337              struct sigscratch *scr)
 338 {
 339         extern char __kernel_sigtramp[];
 340         unsigned long tramp_addr, new_rbs = 0, new_sp;
 341         struct sigframe __user *frame;
 342         long err;
 343
 344         new_sp = scr->pt.r12;
 345         tramp_addr = (unsigned long) __kernel_sigtramp;
 346         if (ka->sa.sa_flags & SA_ONSTACK) {
 347                 int onstack = sas_ss_flags(new_sp);
 348
 349                 if (onstack == 0) {
 350                         new_sp = current->sas_ss_sp + current->sas_ss_size;
 351                         /*
 352                          * We need to check for the register stack being on the
 353                          * signal stack separately, because it's switched
 354                          * separately (memory stack is switched in the kernel,
 355                          * register stack is switched in the signal trampoline).
 356                          */
 357                         if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
 358                                 new_rbs = ALIGN(current->sas_ss_sp,
 359                                                 sizeof(long));
 360                 } else if (onstack == SS_ONSTACK) {
 361                         unsigned long check_sp;
 362
 363                         /*
 364                          * If we are on the alternate signal stack and would
 365                          * overflow it, don't. Return an always-bogus address
 366                          * instead so we will die with SIGSEGV.
 367                          */
 368                         check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
 369                         if (!likely(on_sig_stack(check_sp)))
 370                                 return force_sigsegv_info(sig, (void __user *)
 371                                                           check_sp);
 372                 }
 373         }
 374         frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
 375
 376         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 377                 return force_sigsegv_info(sig, frame);
 378
 379         err  = __put_user(sig, &frame->arg0);
 380         err |= __put_user(&frame->info, &frame->arg1);
 381         err |= __put_user(&frame->sc, &frame->arg2);
 382         err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
 383         err |= __put_user(0, &frame->sc.sc_loadrs);     /* initialize to zero */
 384         err |= __put_user(ka->sa.sa_handler, &frame->handler);
 385
 386         err |= copy_siginfo_to_user(&frame->info, info);
 387
 388         err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
 389         err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
 390         err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
 391         err |= setup_sigcontext(&frame->sc, set, scr);
 392
 393         if (unlikely(err))
 394                 return force_sigsegv_info(sig, frame);
 395
 396         scr->pt.r12 = (unsigned long) frame - 16;       /* new stack pointer */
 397         scr->pt.ar_fpsr = FPSR_DEFAULT;                 /* reset fpsr for signal handler */
 398         scr->pt.cr_iip = tramp_addr;
 399         ia64_psr(&scr->pt)->ri = 0;                     /* start executing in first slot */
 400         ia64_psr(&scr->pt)->be = 0;                     /* force little-endian byte-order */
 401         /*
 402          * Force the interruption function mask to zero.  This has no effect when a
 403          * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
 404          * ignored), but it has the desirable effect of making it possible to deliver a
 405          * signal with an incomplete register frame (which happens when a mandatory RSE
 406          * load faults).  Furthermore, it has no negative effect on the getting the user's
 407          * dirty partition preserved, because that's governed by scr->pt.loadrs.
 408          */
 409         scr->pt.cr_ifs = (1UL << 63);
 410
 411         /*
 412          * Note: this affects only the NaT bits of the scratch regs (the ones saved in
 413          * pt_regs), which is exactly what we want.
 414          */
 415         scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
 416
 417 #if DEBUG_SIG
 418         printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
 419                current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
 420 #endif
 421         return 1;
 422 }
 423
 424 static long
 425 handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
 426                struct sigscratch *scr)
 427 {
 428         if (IS_IA32_PROCESS(&scr->pt)) {
 429                 /* send signal to IA-32 process */
 430                 if (!ia32_setup_frame1(sig, ka, info, oldset, &scr->pt))
 431                         return 0;
 432         } else
 433                 /* send signal to IA-64 process */
 434                 if (!setup_frame(sig, ka, info, oldset, scr))
 435                         return 0;
 436
 437         spin_lock_irq(&current->sighand->siglock);
 438         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 439         if (!(ka->sa.sa_flags & SA_NODEFER))
 440                 sigaddset(&current->blocked, sig);
 441         recalc_sigpending();
 442         spin_unlock_irq(&current->sighand->siglock);
 443
 444         /*
 445          * Let tracing know that we've done the handler setup.
 446          */
 447         tracehook_signal_handler(sig, info, ka, &scr->pt,
 448                                  test_thread_flag(TIF_SINGLESTEP));
 449
 450         return 1;
 451 }
 452
 453 /*
 454  * Note that `init' is a special process: it doesn't get signals it doesn't want to
 455  * handle.  Thus you cannot kill init even with a SIGKILL even by mistake.
 456  */
 457 void
 458 ia64_do_signal (struct sigscratch *scr, long in_syscall)
 459 {
 460         struct k_sigaction ka;
 461         sigset_t *oldset;
 462         siginfo_t info;
 463         long restart = in_syscall;
 464         long errno = scr->pt.r8;
 465 #       define ERR_CODE(c)      (IS_IA32_PROCESS(&scr->pt) ? -(c) : (c))
 466
 467         /*
 468          * In the ia64_leave_kernel code path, we want the common case to go fast, which
 469          * is why we may in certain cases get here from kernel mode. Just return without
 470          * doing anything if so.
 471          */
 472         if (!user_mode(&scr->pt))
 473                 return;
 474
 475         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 476                 oldset = &current->saved_sigmask;
 477         else
 478                 oldset = &current->blocked;
 479
 480         /*
 481          * This only loops in the rare cases of handle_signal() failing, in which case we
 482          * need to push through a forced SIGSEGV.
 483          */
 484         while (1) {
 485                 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
 486
 487                 /*
 488                  * get_signal_to_deliver() may have run a debugger (via notify_parent())
 489                  * and the debugger may have modified the state (e.g., to arrange for an
 490                  * inferior call), thus it's important to check for restarting _after_
 491                  * get_signal_to_deliver().
 492                  */
 493                 if (IS_IA32_PROCESS(&scr->pt)) {
 494                         if (in_syscall) {
 495                                 if (errno >= 0)
 496                                         restart = 0;
 497                                 else
 498                                         errno = -errno;
 499                         }
 500                 } else if ((long) scr->pt.r10 != -1)
 501                         /*
 502                          * A system calls has to be restarted only if one of the error codes
 503                          * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned.  If r10
 504                          * isn't -1 then r8 doesn't hold an error code and we don't need to
 505                          * restart the syscall, so we can clear the "restart" flag here.
 506                          */
 507                         restart = 0;
 508
 509                 if (signr <= 0)
 510                         break;
 511
 512                 if (unlikely(restart)) {
 513                         switch (errno) {
 514                               case ERESTART_RESTARTBLOCK:
 515                               case ERESTARTNOHAND:
 516                                 scr->pt.r8 = ERR_CODE(EINTR);
 517                                 /* note: scr->pt.r10 is already -1 */
 518                                 break;
 519
 520                               case ERESTARTSYS:
 521                                 if ((ka.sa.sa_flags & SA_RESTART) == 0) {
 522                                         scr->pt.r8 = ERR_CODE(EINTR);
 523                                         /* note: scr->pt.r10 is already -1 */
 524                                         break;
 525                                 }
 526                               case ERESTARTNOINTR:
 527                                 if (IS_IA32_PROCESS(&scr->pt)) {
 528                                         scr->pt.r8 = scr->pt.r1;
 529                                         scr->pt.cr_iip -= 2;
 530                                 } else
 531                                         ia64_decrement_ip(&scr->pt);
 532                                 restart = 0; /* don't restart twice if handle_signal() fails... */
 533                         }
 534                 }
 535
 536                 /*
 537                  * Whee!  Actually deliver the signal.  If the delivery failed, we need to
 538                  * continue to iterate in this loop so we can deliver the SIGSEGV...
 539                  */
 540                 if (handle_signal(signr, &ka, &info, oldset, scr)) {
 541                         /*
 542                          * A signal was successfully delivered; the saved
 543                          * sigmask will have been stored in the signal frame,
 544                          * and will be restored by sigreturn, so we can simply
 545                          * clear the TS_RESTORE_SIGMASK flag.
 546                          */
 547                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 548                         return;
 549                 }
 550         }
 551
 552         /* Did we come from a system call? */
 553         if (restart) {
 554                 /* Restart the system call - no handlers present */
 555                 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
 556                     || errno == ERESTART_RESTARTBLOCK)
 557                 {
 558                         if (IS_IA32_PROCESS(&scr->pt)) {
 559                                 scr->pt.r8 = scr->pt.r1;
 560                                 scr->pt.cr_iip -= 2;
 561                                 if (errno == ERESTART_RESTARTBLOCK)
 562                                         scr->pt.r8 = 0; /* x86 version of __NR_restart_syscall */
 563                         } else {
 564                                 /*
 565                                  * Note: the syscall number is in r15 which is saved in
 566                                  * pt_regs so all we need to do here is adjust ip so that
 567                                  * the "break" instruction gets re-executed.
 568                                  */
 569                                 ia64_decrement_ip(&scr->pt);
 570                                 if (errno == ERESTART_RESTARTBLOCK)
 571                                         scr->pt.r15 = __NR_restart_syscall;
 572                         }
 573                 }
 574         }
 575
 576         /* if there's no signal to deliver, we just put the saved sigmask
 577          * back */
 578         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 579                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 580                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 581         }
 582 }