arch/mips/kernel/signal.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1991, 1992  Linus Torvalds
   7  * Copyright (C) 1994 - 2000  Ralf Baechle
   8  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   9  */
  10 #include <linux/cache.h>
  11 #include <linux/sched.h>
  12 #include <linux/mm.h>
  13 #include <linux/personality.h>
  14 #include <linux/smp.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/kernel.h>
  17 #include <linux/signal.h>
  18 #include <linux/errno.h>
  19 #include <linux/wait.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/unistd.h>
  22 #include <linux/compiler.h>
  23
  24 #include <asm/abi.h>
  25 #include <asm/asm.h>
  26 #include <linux/bitops.h>
  27 #include <asm/cacheflush.h>
  28 #include <asm/fpu.h>
  29 #include <asm/sim.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/ucontext.h>
  32 #include <asm/cpu-features.h>
  33 #include <asm/war.h>
  34
  35 #include "signal-common.h"
  36
  37 /*
  38  * Horribly complicated - with the bloody RM9000 workarounds enabled
  39  * the signal trampolines is moving to the end of the structure so we can
  40  * increase the alignment without breaking software compatibility.
  41  */
  42 #if ICACHE_REFILLS_WORKAROUND_WAR == 0
  43
  44 struct sigframe {
  45         u32 sf_ass[4];          /* argument save space for o32 */
  46         u32 sf_code[2];         /* signal trampoline */
  47         struct sigcontext sf_sc;
  48         sigset_t sf_mask;
  49 };
  50
  51 struct rt_sigframe {
  52         u32 rs_ass[4];          /* argument save space for o32 */
  53         u32 rs_code[2];         /* signal trampoline */
  54         struct siginfo rs_info;
  55         struct ucontext rs_uc;
  56 };
  57
  58 #else
  59
  60 struct sigframe {
  61         u32 sf_ass[4];                  /* argument save space for o32 */
  62         u32 sf_pad[2];
  63         struct sigcontext sf_sc;        /* hw context */
  64         sigset_t sf_mask;
  65         u32 sf_code[8] ____cacheline_aligned;   /* signal trampoline */
  66 };
  67
  68 struct rt_sigframe {
  69         u32 rs_ass[4];                  /* argument save space for o32 */
  70         u32 rs_pad[2];
  71         struct siginfo rs_info;
  72         struct ucontext rs_uc;
  73         u32 rs_code[8] ____cacheline_aligned;   /* signal trampoline */
  74 };
  75
  76 #endif
  77
  78 /*
  79  * Helper routines
  80  */
  81 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  82 {
  83         int err = 0;
  84         int i;
  85
  86         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
  87
  88         err |= __put_user(0, &sc->sc_regs[0]);
  89         for (i = 1; i < 32; i++)
  90                 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
  91
  92         err |= __put_user(regs->hi, &sc->sc_mdhi);
  93         err |= __put_user(regs->lo, &sc->sc_mdlo);
  94         if (cpu_has_dsp) {
  95                 err |= __put_user(mfhi1(), &sc->sc_hi1);
  96                 err |= __put_user(mflo1(), &sc->sc_lo1);
  97                 err |= __put_user(mfhi2(), &sc->sc_hi2);
  98                 err |= __put_user(mflo2(), &sc->sc_lo2);
  99                 err |= __put_user(mfhi3(), &sc->sc_hi3);
 100                 err |= __put_user(mflo3(), &sc->sc_lo3);
 101                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 102         }
 103
 104         err |= __put_user(!!used_math(), &sc->sc_used_math);
 105
 106         if (used_math()) {
 107                 /*
 108                  * Save FPU state to signal context. Signal handler
 109                  * will "inherit" current FPU state.
 110                  */
 111                 preempt_disable();
 112
 113                 if (!is_fpu_owner()) {
 114                         own_fpu();
 115                         restore_fp(current);
 116                 }
 117                 err |= save_fp_context(sc);
 118
 119                 preempt_enable();
 120         }
 121         return err;
 122 }
 123
 124 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 125 {
 126         unsigned int used_math;
 127         unsigned long treg;
 128         int err = 0;
 129         int i;
 130
 131         /* Always make any pending restarted system calls return -EINTR */
 132         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 133
 134         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 135         err |= __get_user(regs->hi, &sc->sc_mdhi);
 136         err |= __get_user(regs->lo, &sc->sc_mdlo);
 137         if (cpu_has_dsp) {
 138                 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 139                 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 140                 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 141                 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 142                 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 143                 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 144                 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 145         }
 146
 147         for (i = 1; i < 32; i++)
 148                 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 149
 150         err |= __get_user(used_math, &sc->sc_used_math);
 151         conditional_used_math(used_math);
 152
 153         preempt_disable();
 154
 155         if (used_math()) {
 156                 /* restore fpu context if we have used it before */
 157                 own_fpu();
 158                 err |= restore_fp_context(sc);
 159         } else {
 160                 /* signal handler may have used FPU.  Give it up. */
 161                 lose_fpu();
 162         }
 163
 164         preempt_enable();
 165
 166         return err;
 167 }
 168
 169 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 170                           size_t frame_size)
 171 {
 172         unsigned long sp;
 173
 174         /* Default to using normal stack */
 175         sp = regs->regs[29];
 176
 177         /*
 178          * FPU emulator may have it's own trampoline active just
 179          * above the user stack, 16-bytes before the next lowest
 180          * 16 byte boundary.  Try to avoid trashing it.
 181          */
 182         sp -= 32;
 183
 184         /* This is the X/Open sanctioned signal stack switching.  */
 185         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 186                 sp = current->sas_ss_sp + current->sas_ss_size;
 187
 188         return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
 189 }
 190
 191 int install_sigtramp(unsigned int __user *tramp, unsigned int syscall)
 192 {
 193         int err;
 194
 195         /*
 196          * Set up the return code ...
 197          *
 198          *         li      v0, __NR__foo_sigreturn
 199          *         syscall
 200          */
 201
 202         err = __put_user(0x24020000 + syscall, tramp + 0);
 203         err |= __put_user(0x0000000c         , tramp + 1);
 204         if (ICACHE_REFILLS_WORKAROUND_WAR) {
 205                 err |= __put_user(0, tramp + 2);
 206                 err |= __put_user(0, tramp + 3);
 207                 err |= __put_user(0, tramp + 4);
 208                 err |= __put_user(0, tramp + 5);
 209                 err |= __put_user(0, tramp + 6);
 210                 err |= __put_user(0, tramp + 7);
 211         }
 212         flush_cache_sigtramp((unsigned long) tramp);
 213
 214         return err;
 215 }
 216
 217 /*
 218  * Atomically swap in the new signal mask, and wait for a signal.
 219  */
 220
 221 #ifdef CONFIG_TRAD_SIGNALS
 222 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
 223 {
 224         sigset_t newset;
 225         sigset_t __user *uset;
 226
 227         uset = (sigset_t __user *) regs.regs[4];
 228         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
 229                 return -EFAULT;
 230         sigdelsetmask(&newset, ~_BLOCKABLE);
 231
 232         spin_lock_irq(&current->sighand->siglock);
 233         current->saved_sigmask = current->blocked;
 234         current->blocked = newset;
 235         recalc_sigpending();
 236         spin_unlock_irq(&current->sighand->siglock);
 237
 238         current->state = TASK_INTERRUPTIBLE;
 239         schedule();
 240         set_thread_flag(TIF_RESTORE_SIGMASK);
 241         return -ERESTARTNOHAND;
 242 }
 243 #endif
 244
 245 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 246 {
 247         sigset_t newset;
 248         sigset_t __user *unewset;
 249         size_t sigsetsize;
 250
 251         /* XXX Don't preclude handling different sized sigset_t's.  */
 252         sigsetsize = regs.regs[5];
 253         if (sigsetsize != sizeof(sigset_t))
 254                 return -EINVAL;
 255
 256         unewset = (sigset_t __user *) regs.regs[4];
 257         if (copy_from_user(&newset, unewset, sizeof(newset)))
 258                 return -EFAULT;
 259         sigdelsetmask(&newset, ~_BLOCKABLE);
 260
 261         spin_lock_irq(&current->sighand->siglock);
 262         current->saved_sigmask = current->blocked;
 263         current->blocked = newset;
 264         recalc_sigpending();
 265         spin_unlock_irq(&current->sighand->siglock);
 266
 267         current->state = TASK_INTERRUPTIBLE;
 268         schedule();
 269         set_thread_flag(TIF_RESTORE_SIGMASK);
 270         return -ERESTARTNOHAND;
 271 }
 272
 273 #ifdef CONFIG_TRAD_SIGNALS
 274 asmlinkage int sys_sigaction(int sig, const struct sigaction __user *act,
 275         struct sigaction __user *oact)
 276 {
 277         struct k_sigaction new_ka, old_ka;
 278         int ret;
 279         int err = 0;
 280
 281         if (act) {
 282                 old_sigset_t mask;
 283
 284                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 285                         return -EFAULT;
 286                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 287                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 288                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 289                 if (err)
 290                         return -EFAULT;
 291
 292                 siginitset(&new_ka.sa.sa_mask, mask);
 293         }
 294
 295         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 296
 297         if (!ret && oact) {
 298                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 299                         return -EFAULT;
 300                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 301                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 302                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 303                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 304                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 305                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 306                 if (err)
 307                         return -EFAULT;
 308         }
 309
 310         return ret;
 311 }
 312 #endif
 313
 314 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 315 {
 316         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
 317         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
 318         unsigned long usp = regs.regs[29];
 319
 320         return do_sigaltstack(uss, uoss, usp);
 321 }
 322
 323 #ifdef CONFIG_TRAD_SIGNALS
 324 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 325 {
 326         struct sigframe __user *frame;
 327         sigset_t blocked;
 328
 329         frame = (struct sigframe __user *) regs.regs[29];
 330         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 331                 goto badframe;
 332         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 333                 goto badframe;
 334
 335         sigdelsetmask(&blocked, ~_BLOCKABLE);
 336         spin_lock_irq(&current->sighand->siglock);
 337         current->blocked = blocked;
 338         recalc_sigpending();
 339         spin_unlock_irq(&current->sighand->siglock);
 340
 341         if (restore_sigcontext(&regs, &frame->sf_sc))
 342                 goto badframe;
 343
 344         /*
 345          * Don't let your children do this ...
 346          */
 347         __asm__ __volatile__(
 348                 "move\t$29, %0\n\t"
 349                 "j\tsyscall_exit"
 350                 :/* no outputs */
 351                 :"r" (&regs));
 352         /* Unreached */
 353
 354 badframe:
 355         force_sig(SIGSEGV, current);
 356 }
 357 #endif /* CONFIG_TRAD_SIGNALS */
 358
 359 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 360 {
 361         struct rt_sigframe __user *frame;
 362         sigset_t set;
 363         stack_t st;
 364
 365         frame = (struct rt_sigframe __user *) regs.regs[29];
 366         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 367                 goto badframe;
 368         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 369                 goto badframe;
 370
 371         sigdelsetmask(&set, ~_BLOCKABLE);
 372         spin_lock_irq(&current->sighand->siglock);
 373         current->blocked = set;
 374         recalc_sigpending();
 375         spin_unlock_irq(&current->sighand->siglock);
 376
 377         if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
 378                 goto badframe;
 379
 380         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 381                 goto badframe;
 382         /* It is more difficult to avoid calling this function than to
 383            call it and ignore errors.  */
 384         do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
 385
 386         /*
 387          * Don't let your children do this ...
 388          */
 389         __asm__ __volatile__(
 390                 "move\t$29, %0\n\t"
 391                 "j\tsyscall_exit"
 392                 :/* no outputs */
 393                 :"r" (&regs));
 394         /* Unreached */
 395
 396 badframe:
 397         force_sig(SIGSEGV, current);
 398 }
 399
 400 #ifdef CONFIG_TRAD_SIGNALS
 401 static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
 402         int signr, sigset_t *set)
 403 {
 404         struct sigframe __user *frame;
 405         int err = 0;
 406
 407         frame = get_sigframe(ka, regs, sizeof(*frame));
 408         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 409                 goto give_sigsegv;
 410
 411         err |= install_sigtramp(frame->sf_code, __NR_sigreturn);
 412
 413         err |= setup_sigcontext(regs, &frame->sf_sc);
 414         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 415         if (err)
 416                 goto give_sigsegv;
 417
 418         /*
 419          * Arguments to signal handler:
 420          *
 421          *   a0 = signal number
 422          *   a1 = 0 (should be cause)
 423          *   a2 = pointer to struct sigcontext
 424          *
 425          * $25 and c0_epc point to the signal handler, $29 points to the
 426          * struct sigframe.
 427          */
 428         regs->regs[ 4] = signr;
 429         regs->regs[ 5] = 0;
 430         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 431         regs->regs[29] = (unsigned long) frame;
 432         regs->regs[31] = (unsigned long) frame->sf_code;
 433         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 434
 435         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 436                current->comm, current->pid,
 437                frame, regs->cp0_epc, regs->regs[31]);
 438         return 0;
 439
 440 give_sigsegv:
 441         force_sigsegv(signr, current);
 442         return -EFAULT;
 443 }
 444 #endif
 445
 446 static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
 447         int signr, sigset_t *set, siginfo_t *info)
 448 {
 449         struct rt_sigframe __user *frame;
 450         int err = 0;
 451
 452         frame = get_sigframe(ka, regs, sizeof(*frame));
 453         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 454                 goto give_sigsegv;
 455
 456         err |= install_sigtramp(frame->rs_code, __NR_rt_sigreturn);
 457
 458         /* Create siginfo.  */
 459         err |= copy_siginfo_to_user(&frame->rs_info, info);
 460
 461         /* Create the ucontext.  */
 462         err |= __put_user(0, &frame->rs_uc.uc_flags);
 463         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 464         err |= __put_user((void __user *)current->sas_ss_sp,
 465                           &frame->rs_uc.uc_stack.ss_sp);
 466         err |= __put_user(sas_ss_flags(regs->regs[29]),
 467                           &frame->rs_uc.uc_stack.ss_flags);
 468         err |= __put_user(current->sas_ss_size,
 469                           &frame->rs_uc.uc_stack.ss_size);
 470         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 471         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 472
 473         if (err)
 474                 goto give_sigsegv;
 475
 476         /*
 477          * Arguments to signal handler:
 478          *
 479          *   a0 = signal number
 480          *   a1 = 0 (should be cause)
 481          *   a2 = pointer to ucontext
 482          *
 483          * $25 and c0_epc point to the signal handler, $29 points to
 484          * the struct rt_sigframe.
 485          */
 486         regs->regs[ 4] = signr;
 487         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 488         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 489         regs->regs[29] = (unsigned long) frame;
 490         regs->regs[31] = (unsigned long) frame->rs_code;
 491         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 492
 493         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 494                current->comm, current->pid,
 495                frame, regs->cp0_epc, regs->regs[31]);
 496
 497         return 0;
 498
 499 give_sigsegv:
 500         force_sigsegv(signr, current);
 501         return -EFAULT;
 502 }
 503
 504 struct mips_abi mips_abi = {
 505 #ifdef CONFIG_TRAD_SIGNALS
 506         .setup_frame    = setup_frame,
 507 #endif
 508         .setup_rt_frame = setup_rt_frame,
 509         .restart        = __NR_restart_syscall
 510 };
 511
 512 static int handle_signal(unsigned long sig, siginfo_t *info,
 513         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 514 {
 515         int ret;
 516
 517         switch(regs->regs[0]) {
 518         case ERESTART_RESTARTBLOCK:
 519         case ERESTARTNOHAND:
 520                 regs->regs[2] = EINTR;
 521                 break;
 522         case ERESTARTSYS:
 523                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 524                         regs->regs[2] = EINTR;
 525                         break;
 526                 }
 527         /* fallthrough */
 528         case ERESTARTNOINTR:            /* Userland will reload $v0.  */
 529                 regs->regs[7] = regs->regs[26];
 530                 regs->cp0_epc -= 8;
 531         }
 532
 533         regs->regs[0] = 0;              /* Don't deal with this again.  */
 534
 535         if (sig_uses_siginfo(ka))
 536                 ret = current->thread.abi->setup_rt_frame(ka, regs, sig, oldset, info);
 537         else
 538                 ret = current->thread.abi->setup_frame(ka, regs, sig, oldset);
 539
 540         spin_lock_irq(&current->sighand->siglock);
 541         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 542         if (!(ka->sa.sa_flags & SA_NODEFER))
 543                 sigaddset(&current->blocked,sig);
 544         recalc_sigpending();
 545         spin_unlock_irq(&current->sighand->siglock);
 546
 547         return ret;
 548 }
 549
 550 static void do_signal(struct pt_regs *regs)
 551 {
 552         struct k_sigaction ka;
 553         sigset_t *oldset;
 554         siginfo_t info;
 555         int signr;
 556
 557         /*
 558          * We want the common case to go fast, which is why we may in certain
 559          * cases get here from kernel mode. Just return without doing anything
 560          * if so.
 561          */
 562         if (!user_mode(regs))
 563                 return;
 564
 565         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 566                 oldset = &current->saved_sigmask;
 567         else
 568                 oldset = &current->blocked;
 569
 570         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 571         if (signr > 0) {
 572                 /* Whee!  Actually deliver the signal.  */
 573                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 574                         /*
 575                          * A signal was successfully delivered; the saved
 576                          * sigmask will have been stored in the signal frame,
 577                          * and will be restored by sigreturn, so we can simply
 578                          * clear the TIF_RESTORE_SIGMASK flag.
 579                          */
 580                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 581                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 582                 }
 583
 584                 return;
 585         }
 586
 587         /*
 588          * Who's code doesn't conform to the restartable syscall convention
 589          * dies here!!!  The li instruction, a single machine instruction,
 590          * must directly be followed by the syscall instruction.
 591          */
 592         if (regs->regs[0]) {
 593                 if (regs->regs[2] == ERESTARTNOHAND ||
 594                     regs->regs[2] == ERESTARTSYS ||
 595                     regs->regs[2] == ERESTARTNOINTR) {
 596                         regs->regs[7] = regs->regs[26];
 597                         regs->cp0_epc -= 8;
 598                 }
 599                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
 600                         regs->regs[2] = current->thread.abi->restart;
 601                         regs->regs[7] = regs->regs[26];
 602                         regs->cp0_epc -= 4;
 603                 }
 604                 regs->regs[0] = 0;      /* Don't deal with this again.  */
 605         }
 606
 607         /*
 608          * If there's no signal to deliver, we just put the saved sigmask
 609          * back
 610          */
 611         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 612                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 613                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 614         }
 615 }
 616
 617 /*
 618  * notification of userspace execution resumption
 619  * - triggered by the TIF_WORK_MASK flags
 620  */
 621 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 622         __u32 thread_info_flags)
 623 {
 624         /* deal with pending signal delivery */
 625         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 626                 do_signal(regs);
 627 }