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