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/sched.h>
  15 #include <linux/signal.h>
  16 #include <linux/smp.h>
  17 #include <linux/smp_lock.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 long
  45 ia64_rt_sigsuspend (sigset_t __user *uset, size_t sigsetsize, struct sigscratch *scr)
  46 {
  47         sigset_t oldset, set;
  48
  49         /* XXX: Don't preclude handling different sized sigset_t's.  */
  50         if (sigsetsize != sizeof(sigset_t))
  51                 return -EINVAL;
  52
  53         if (!access_ok(VERIFY_READ, uset, sigsetsize))
  54                 return -EFAULT;
  55
  56         if (GET_SIGSET(&set, uset))
  57                 return -EFAULT;
  58
  59         sigdelsetmask(&set, ~_BLOCKABLE);
  60
  61         spin_lock_irq(&current->sighand->siglock);
  62         {
  63                 oldset = current->blocked;
  64                 current->blocked = set;
  65                 recalc_sigpending();
  66         }
  67         spin_unlock_irq(&current->sighand->siglock);
  68
  69         /*
  70          * The return below usually returns to the signal handler.  We need to
  71          * pre-set the correct error code here to ensure that the right values
  72          * get saved in sigcontext by ia64_do_signal.
  73          */
  74         scr->pt.r8 = EINTR;
  75         scr->pt.r10 = -1;
  76
  77         while (1) {
  78                 current->state = TASK_INTERRUPTIBLE;
  79                 schedule();
  80                 if (ia64_do_signal(&oldset, scr, 1))
  81                         return -EINTR;
  82         }
  83 }
  84
  85 asmlinkage long
  86 sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
  87                  long arg3, long arg4, long arg5, long arg6, long arg7,
  88                  struct pt_regs regs)
  89 {
  90         return do_sigaltstack(uss, uoss, regs.r12);
  91 }
  92
  93 static long
  94 restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
  95 {
  96         unsigned long ip, flags, nat, um, cfm, rsc;
  97         long err;
  98
  99         /* Always make any pending restarted system calls return -EINTR */
 100         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 101
 102         /* restore scratch that always needs gets updated during signal delivery: */
 103         err  = __get_user(flags, &sc->sc_flags);
 104         err |= __get_user(nat, &sc->sc_nat);
 105         err |= __get_user(ip, &sc->sc_ip);                      /* instruction pointer */
 106         err |= __get_user(cfm, &sc->sc_cfm);
 107         err |= __get_user(um, &sc->sc_um);                      /* user mask */
 108         err |= __get_user(rsc, &sc->sc_ar_rsc);
 109         err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
 110         err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
 111         err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
 112         err |= __get_user(scr->pt.pr, &sc->sc_pr);              /* predicates */
 113         err |= __get_user(scr->pt.b0, &sc->sc_br[0]);           /* b0 (rp) */
 114         err |= __get_user(scr->pt.b6, &sc->sc_br[6]);           /* b6 */
 115         err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
 116         err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8);       /* r8-r11 */
 117         err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8);     /* r12-r13 */
 118         err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8);       /* r15 */
 119
 120         scr->pt.cr_ifs = cfm | (1UL << 63);
 121         scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
 122
 123         /* establish new instruction pointer: */
 124         scr->pt.cr_iip = ip & ~0x3UL;
 125         ia64_psr(&scr->pt)->ri = ip & 0x3;
 126         scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
 127
 128         scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
 129
 130         if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
 131                 /* Restore most scratch-state only when not in syscall. */
 132                 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);              /* ar.ccv */
 133                 err |= __get_user(scr->pt.b7, &sc->sc_br[7]);                   /* b7 */
 134                 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]);                 /* r14 */
 135                 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
 136                 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8);       /* r2-r3 */
 137                 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8);    /* r16-r31 */
 138         }
 139
 140         if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
 141                 struct ia64_psr *psr = ia64_psr(&scr->pt);
 142
 143                 __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
 144                 psr->mfh = 0;   /* drop signal handler's fph contents... */
 145                 preempt_disable();
 146                 if (psr->dfh)
 147                         ia64_drop_fpu(current);
 148                 else {
 149                         /* We already own the local fph, otherwise psr->dfh wouldn't be 0.  */
 150                         __ia64_load_fpu(current->thread.fph);
 151                         ia64_set_local_fpu_owner(current);
 152                 }
 153                 preempt_enable();
 154         }
 155         return err;
 156 }
 157
 158 int
 159 copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
 160 {
 161         if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
 162                 return -EFAULT;
 163         if (from->si_code < 0) {
 164                 if (__copy_to_user(to, from, sizeof(siginfo_t)))
 165                         return -EFAULT;
 166                 return 0;
 167         } else {
 168                 int err;
 169
 170                 /*
 171                  * If you change siginfo_t structure, please be sure this code is fixed
 172                  * accordingly.  It should never copy any pad contained in the structure
 173                  * to avoid security leaks, but must copy the generic 3 ints plus the
 174                  * relevant union member.
 175                  */
 176                 err = __put_user(from->si_signo, &to->si_signo);
 177                 err |= __put_user(from->si_errno, &to->si_errno);
 178                 err |= __put_user((short)from->si_code, &to->si_code);
 179                 switch (from->si_code >> 16) {
 180                       case __SI_FAULT >> 16:
 181                         err |= __put_user(from->si_flags, &to->si_flags);
 182                         err |= __put_user(from->si_isr, &to->si_isr);
 183                       case __SI_POLL >> 16:
 184                         err |= __put_user(from->si_addr, &to->si_addr);
 185                         err |= __put_user(from->si_imm, &to->si_imm);
 186                         break;
 187                       case __SI_TIMER >> 16:
 188                         err |= __put_user(from->si_tid, &to->si_tid);
 189                         err |= __put_user(from->si_overrun, &to->si_overrun);
 190                         err |= __put_user(from->si_ptr, &to->si_ptr);
 191                         break;
 192                       case __SI_RT >> 16:       /* Not generated by the kernel as of now.  */
 193                       case __SI_MESGQ >> 16:
 194                         err |= __put_user(from->si_uid, &to->si_uid);
 195                         err |= __put_user(from->si_pid, &to->si_pid);
 196                         err |= __put_user(from->si_ptr, &to->si_ptr);
 197                         break;
 198                       case __SI_CHLD >> 16:
 199                         err |= __put_user(from->si_utime, &to->si_utime);
 200                         err |= __put_user(from->si_stime, &to->si_stime);
 201                         err |= __put_user(from->si_status, &to->si_status);
 202                       default:
 203                         err |= __put_user(from->si_uid, &to->si_uid);
 204                         err |= __put_user(from->si_pid, &to->si_pid);
 205                         break;
 206                 }
 207                 return err;
 208         }
 209 }
 210
 211 long
 212 ia64_rt_sigreturn (struct sigscratch *scr)
 213 {
 214         extern char ia64_strace_leave_kernel, ia64_leave_kernel;
 215         struct sigcontext __user *sc;
 216         struct siginfo si;
 217         sigset_t set;
 218         long retval;
 219
 220         sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
 221
 222         /*
 223          * When we return to the previously executing context, r8 and r10 have already
 224          * been setup the way we want them.  Indeed, if the signal wasn't delivered while
 225          * in a system call, we must not touch r8 or r10 as otherwise user-level state
 226          * could be corrupted.
 227          */
 228         retval = (long) &ia64_leave_kernel;
 229         if (test_thread_flag(TIF_SYSCALL_TRACE)
 230             || test_thread_flag(TIF_SYSCALL_AUDIT))
 231                 /*
 232                  * strace expects to be notified after sigreturn returns even though the
 233                  * context to which we return may not be in the middle of a syscall.
 234                  * Thus, the return-value that strace displays for sigreturn is
 235                  * meaningless.
 236                  */
 237                 retval = (long) &ia64_strace_leave_kernel;
 238
 239         if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
 240                 goto give_sigsegv;
 241
 242         if (GET_SIGSET(&set, &sc->sc_mask))
 243                 goto give_sigsegv;
 244
 245         sigdelsetmask(&set, ~_BLOCKABLE);
 246
 247         spin_lock_irq(&current->sighand->siglock);
 248         {
 249                 current->blocked = set;
 250                 recalc_sigpending();
 251         }
 252         spin_unlock_irq(&current->sighand->siglock);
 253
 254         if (restore_sigcontext(sc, scr))
 255                 goto give_sigsegv;
 256
 257 #if DEBUG_SIG
 258         printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
 259                current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
 260 #endif
 261         /*
 262          * It is more difficult to avoid calling this function than to
 263          * call it and ignore errors.
 264          */
 265         do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
 266         return retval;
 267
 268   give_sigsegv:
 269         si.si_signo = SIGSEGV;
 270         si.si_errno = 0;
 271         si.si_code = SI_KERNEL;
 272         si.si_pid = current->pid;
 273         si.si_uid = current->uid;
 274         si.si_addr = sc;
 275         force_sig_info(SIGSEGV, &si, current);
 276         return retval;
 277 }
 278
 279 /*
 280  * This does just the minimum required setup of sigcontext.
 281  * Specifically, it only installs data that is either not knowable at
 282  * the user-level or that gets modified before execution in the
 283  * trampoline starts.  Everything else is done at the user-level.
 284  */
 285 static long
 286 setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
 287 {
 288         unsigned long flags = 0, ifs, cfm, nat;
 289         long err;
 290
 291         ifs = scr->pt.cr_ifs;
 292
 293         if (on_sig_stack((unsigned long) sc))
 294                 flags |= IA64_SC_FLAG_ONSTACK;
 295         if ((ifs & (1UL << 63)) == 0)
 296                 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
 297                 flags |= IA64_SC_FLAG_IN_SYSCALL;
 298         cfm = ifs & ((1UL << 38) - 1);
 299         ia64_flush_fph(current);
 300         if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
 301                 flags |= IA64_SC_FLAG_FPH_VALID;
 302                 __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
 303         }
 304
 305         nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
 306
 307         err  = __put_user(flags, &sc->sc_flags);
 308         err |= __put_user(nat, &sc->sc_nat);
 309         err |= PUT_SIGSET(mask, &sc->sc_mask);
 310         err |= __put_user(cfm, &sc->sc_cfm);
 311         err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
 312         err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
 313         err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat);            /* ar.unat */
 314         err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);            /* ar.fpsr */
 315         err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
 316         err |= __put_user(scr->pt.pr, &sc->sc_pr);                      /* predicates */
 317         err |= __put_user(scr->pt.b0, &sc->sc_br[0]);                   /* b0 (rp) */
 318         err |= __put_user(scr->pt.b6, &sc->sc_br[6]);                   /* b6 */
 319         err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8);           /* r1 */
 320         err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8);         /* r8-r11 */
 321         err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8);       /* r12-r13 */
 322         err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8);         /* r15 */
 323         err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
 324
 325         if (flags & IA64_SC_FLAG_IN_SYSCALL) {
 326                 /* Clear scratch registers if the signal interrupted a system call. */
 327                 err |= __put_user(0, &sc->sc_ar_ccv);                           /* ar.ccv */
 328                 err |= __put_user(0, &sc->sc_br[7]);                            /* b7 */
 329                 err |= __put_user(0, &sc->sc_gr[14]);                           /* r14 */
 330                 err |= __clear_user(&sc->sc_ar25, 2*8);                 /* ar.csd & ar.ssd */
 331                 err |= __clear_user(&sc->sc_gr[2], 2*8);                        /* r2-r3 */
 332                 err |= __clear_user(&sc->sc_gr[16], 16*8);                      /* r16-r31 */
 333         } else {
 334                 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
 335                 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);              /* ar.ccv */
 336                 err |= __put_user(scr->pt.b7, &sc->sc_br[7]);                   /* b7 */
 337                 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]);                 /* r14 */
 338                 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
 339                 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8);         /* r2-r3 */
 340                 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8);      /* r16-r31 */
 341         }
 342         return err;
 343 }
 344
 345 /*
 346  * Check whether the register-backing store is already on the signal stack.
 347  */
 348 static inline int
 349 rbs_on_sig_stack (unsigned long bsp)
 350 {
 351         return (bsp - current->sas_ss_sp < current->sas_ss_size);
 352 }
 353
 354 static long
 355 force_sigsegv_info (int sig, void __user *addr)
 356 {
 357         unsigned long flags;
 358         struct siginfo si;
 359
 360         if (sig == SIGSEGV) {
 361                 /*
 362                  * Acquiring siglock around the sa_handler-update is almost
 363                  * certainly overkill, but this isn't a
 364                  * performance-critical path and I'd rather play it safe
 365                  * here than having to debug a nasty race if and when
 366                  * something changes in kernel/signal.c that would make it
 367                  * no longer safe to modify sa_handler without holding the
 368                  * lock.
 369                  */
 370                 spin_lock_irqsave(&current->sighand->siglock, flags);
 371                 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
 372                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 373         }
 374         si.si_signo = SIGSEGV;
 375         si.si_errno = 0;
 376         si.si_code = SI_KERNEL;
 377         si.si_pid = current->pid;
 378         si.si_uid = current->uid;
 379         si.si_addr = addr;
 380         force_sig_info(SIGSEGV, &si, current);
 381         return 0;
 382 }
 383
 384 static long
 385 setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
 386              struct sigscratch *scr)
 387 {
 388         extern char __kernel_sigtramp[];
 389         unsigned long tramp_addr, new_rbs = 0, new_sp;
 390         struct sigframe __user *frame;
 391         long err;
 392
 393         new_sp = scr->pt.r12;
 394         tramp_addr = (unsigned long) __kernel_sigtramp;
 395         if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(new_sp) == 0) {
 396                 new_sp = current->sas_ss_sp + current->sas_ss_size;
 397                 /*
 398                  * We need to check for the register stack being on the signal stack
 399                  * separately, because it's switched separately (memory stack is switched
 400                  * in the kernel, register stack is switched in the signal trampoline).
 401                  */
 402                 if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
 403                         new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1);
 404         }
 405         frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
 406
 407         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 408                 return force_sigsegv_info(sig, frame);
 409
 410         err  = __put_user(sig, &frame->arg0);
 411         err |= __put_user(&frame->info, &frame->arg1);
 412         err |= __put_user(&frame->sc, &frame->arg2);
 413         err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
 414         err |= __put_user(0, &frame->sc.sc_loadrs);     /* initialize to zero */
 415         err |= __put_user(ka->sa.sa_handler, &frame->handler);
 416
 417         err |= copy_siginfo_to_user(&frame->info, info);
 418
 419         err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
 420         err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
 421         err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
 422         err |= setup_sigcontext(&frame->sc, set, scr);
 423
 424         if (unlikely(err))
 425                 return force_sigsegv_info(sig, frame);
 426
 427         scr->pt.r12 = (unsigned long) frame - 16;       /* new stack pointer */
 428         scr->pt.ar_fpsr = FPSR_DEFAULT;                 /* reset fpsr for signal handler */
 429         scr->pt.cr_iip = tramp_addr;
 430         ia64_psr(&scr->pt)->ri = 0;                     /* start executing in first slot */
 431         ia64_psr(&scr->pt)->be = 0;                     /* force little-endian byte-order */
 432         /*
 433          * Force the interruption function mask to zero.  This has no effect when a
 434          * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
 435          * ignored), but it has the desirable effect of making it possible to deliver a
 436          * signal with an incomplete register frame (which happens when a mandatory RSE
 437          * load faults).  Furthermore, it has no negative effect on the getting the user's
 438          * dirty partition preserved, because that's governed by scr->pt.loadrs.
 439          */
 440         scr->pt.cr_ifs = (1UL << 63);
 441
 442         /*
 443          * Note: this affects only the NaT bits of the scratch regs (the ones saved in
 444          * pt_regs), which is exactly what we want.
 445          */
 446         scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
 447
 448 #if DEBUG_SIG
 449         printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
 450                current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
 451 #endif
 452         return 1;
 453 }
 454
 455 static long
 456 handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
 457                struct sigscratch *scr)
 458 {
 459         if (IS_IA32_PROCESS(&scr->pt)) {
 460                 /* send signal to IA-32 process */
 461                 if (!ia32_setup_frame1(sig, ka, info, oldset, &scr->pt))
 462                         return 0;
 463         } else
 464                 /* send signal to IA-64 process */
 465                 if (!setup_frame(sig, ka, info, oldset, scr))
 466                         return 0;
 467
 468         spin_lock_irq(&current->sighand->siglock);
 469         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 470         if (!(ka->sa.sa_flags & SA_NODEFER))
 471                 sigaddset(&current->blocked, sig);
 472         recalc_sigpending();
 473         spin_unlock_irq(&current->sighand->siglock);
 474         return 1;
 475 }
 476
 477 /*
 478  * Note that `init' is a special process: it doesn't get signals it doesn't want to
 479  * handle.  Thus you cannot kill init even with a SIGKILL even by mistake.
 480  */
 481 long
 482 ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
 483 {
 484         struct k_sigaction ka;
 485         siginfo_t info;
 486         long restart = in_syscall;
 487         long errno = scr->pt.r8;
 488 #       define ERR_CODE(c)      (IS_IA32_PROCESS(&scr->pt) ? -(c) : (c))
 489
 490         /*
 491          * In the ia64_leave_kernel code path, we want the common case to go fast, which
 492          * is why we may in certain cases get here from kernel mode. Just return without
 493          * doing anything if so.
 494          */
 495         if (!user_mode(&scr->pt))
 496                 return 0;
 497
 498         if (!oldset)
 499                 oldset = &current->blocked;
 500
 501         /*
 502          * This only loops in the rare cases of handle_signal() failing, in which case we
 503          * need to push through a forced SIGSEGV.
 504          */
 505         while (1) {
 506                 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL);
 507
 508                 /*
 509                  * get_signal_to_deliver() may have run a debugger (via notify_parent())
 510                  * and the debugger may have modified the state (e.g., to arrange for an
 511                  * inferior call), thus it's important to check for restarting _after_
 512                  * get_signal_to_deliver().
 513                  */
 514                 if (IS_IA32_PROCESS(&scr->pt)) {
 515                         if (in_syscall) {
 516                                 if (errno >= 0)
 517                                         restart = 0;
 518                                 else
 519                                         errno = -errno;
 520                         }
 521                 } else if ((long) scr->pt.r10 != -1)
 522                         /*
 523                          * A system calls has to be restarted only if one of the error codes
 524                          * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned.  If r10
 525                          * isn't -1 then r8 doesn't hold an error code and we don't need to
 526                          * restart the syscall, so we can clear the "restart" flag here.
 527                          */
 528                         restart = 0;
 529
 530                 if (signr <= 0)
 531                         break;
 532
 533                 if (unlikely(restart)) {
 534                         switch (errno) {
 535                               case ERESTART_RESTARTBLOCK:
 536                               case ERESTARTNOHAND:
 537                                 scr->pt.r8 = ERR_CODE(EINTR);
 538                                 /* note: scr->pt.r10 is already -1 */
 539                                 break;
 540
 541                               case ERESTARTSYS:
 542                                 if ((ka.sa.sa_flags & SA_RESTART) == 0) {
 543                                         scr->pt.r8 = ERR_CODE(EINTR);
 544                                         /* note: scr->pt.r10 is already -1 */
 545                                         break;
 546                                 }
 547                               case ERESTARTNOINTR:
 548                                 if (IS_IA32_PROCESS(&scr->pt)) {
 549                                         scr->pt.r8 = scr->pt.r1;
 550                                         scr->pt.cr_iip -= 2;
 551                                 } else
 552                                         ia64_decrement_ip(&scr->pt);
 553                                 restart = 0; /* don't restart twice if handle_signal() fails... */
 554                         }
 555                 }
 556
 557                 /*
 558                  * Whee!  Actually deliver the signal.  If the delivery failed, we need to
 559                  * continue to iterate in this loop so we can deliver the SIGSEGV...
 560                  */
 561                 if (handle_signal(signr, &ka, &info, oldset, scr))
 562                         return 1;
 563         }
 564
 565         /* Did we come from a system call? */
 566         if (restart) {
 567                 /* Restart the system call - no handlers present */
 568                 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
 569                     || errno == ERESTART_RESTARTBLOCK)
 570                 {
 571                         if (IS_IA32_PROCESS(&scr->pt)) {
 572                                 scr->pt.r8 = scr->pt.r1;
 573                                 scr->pt.cr_iip -= 2;
 574                                 if (errno == ERESTART_RESTARTBLOCK)
 575                                         scr->pt.r8 = 0; /* x86 version of __NR_restart_syscall */
 576                         } else {
 577                                 /*
 578                                  * Note: the syscall number is in r15 which is saved in
 579                                  * pt_regs so all we need to do here is adjust ip so that
 580                                  * the "break" instruction gets re-executed.
 581                                  */
 582                                 ia64_decrement_ip(&scr->pt);
 583                                 if (errno == ERESTART_RESTARTBLOCK)
 584                                         scr->pt.r15 = __NR_restart_syscall;
 585                         }
 586                 }
 587         }
 588         return 0;
 589 }