release/src-rt-6.x/linux/linux-2.6/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/kernel.h>
  16 #include <linux/signal.h>
  17 #include <linux/errno.h>
  18 #include <linux/wait.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/unistd.h>
  21 #include <linux/compiler.h>
  22 #include <linux/uaccess.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/ucontext.h>
  31 #include <asm/cpu-features.h>
  32 #include <asm/war.h>
  33 #include <asm/vdso.h>
  34
  35 #include "signal-common.h"
  36
  37 struct sigframe {
  38         u32 sf_ass[4];          /* argument save space for o32 */
  39         u32 sf_pad[2];          /* Was: signal trampoline */
  40         struct sigcontext sf_sc;
  41         sigset_t sf_mask;
  42 };
  43
  44 struct rt_sigframe {
  45         u32 rs_ass[4];          /* argument save space for o32 */
  46         u32 rs_pad[2];          /* Was: signal trampoline */
  47         struct siginfo rs_info;
  48         struct ucontext rs_uc;
  49 };
  50
  51 /*
  52  * Helper routines
  53  */
  54 static int protected_save_fp_context(struct sigcontext __user *sc)
  55 {
  56         int err;
  57         while (1) {
  58                 lock_fpu_owner();
  59                 own_fpu_inatomic(1);
  60                 err = save_fp_context(sc); /* this might fail */
  61                 unlock_fpu_owner();
  62                 if (likely(!err))
  63                         break;
  64                 /* touch the sigcontext and try again */
  65                 err = __put_user(0, &sc->sc_fpregs[0]) |
  66                         __put_user(0, &sc->sc_fpregs[31]) |
  67                         __put_user(0, &sc->sc_fpc_csr);
  68                 if (err)
  69                         break;  /* really bad sigcontext */
  70         }
  71         return err;
  72 }
  73
  74 static int protected_restore_fp_context(struct sigcontext __user *sc)
  75 {
  76         int err, tmp __maybe_unused;
  77         while (1) {
  78                 lock_fpu_owner();
  79                 own_fpu_inatomic(0);
  80                 err = restore_fp_context(sc); /* this might fail */
  81                 unlock_fpu_owner();
  82                 if (likely(!err))
  83                         break;
  84                 /* touch the sigcontext and try again */
  85                 err = __get_user(tmp, &sc->sc_fpregs[0]) |
  86                         __get_user(tmp, &sc->sc_fpregs[31]) |
  87                         __get_user(tmp, &sc->sc_fpc_csr);
  88                 if (err)
  89                         break;  /* really bad sigcontext */
  90         }
  91         return err;
  92 }
  93
  94 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  95 {
  96         int err = 0;
  97         int i;
  98         unsigned int used_math;
  99
 100         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 101
 102         err |= __put_user(0, &sc->sc_regs[0]);
 103         for (i = 1; i < 32; i++)
 104                 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
 105
 106 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 107         err |= __put_user(regs->acx, &sc->sc_acx);
 108 #endif
 109         err |= __put_user(regs->hi, &sc->sc_mdhi);
 110         err |= __put_user(regs->lo, &sc->sc_mdlo);
 111         if (cpu_has_dsp) {
 112                 err |= __put_user(mfhi1(), &sc->sc_hi1);
 113                 err |= __put_user(mflo1(), &sc->sc_lo1);
 114                 err |= __put_user(mfhi2(), &sc->sc_hi2);
 115                 err |= __put_user(mflo2(), &sc->sc_lo2);
 116                 err |= __put_user(mfhi3(), &sc->sc_hi3);
 117                 err |= __put_user(mflo3(), &sc->sc_lo3);
 118                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 119         }
 120
 121         used_math = !!used_math();
 122         err |= __put_user(used_math, &sc->sc_used_math);
 123
 124         if (used_math) {
 125                 /*
 126                  * Save FPU state to signal context. Signal handler
 127                  * will "inherit" current FPU state.
 128                  */
 129                 err |= protected_save_fp_context(sc);
 130         }
 131         return err;
 132 }
 133
 134 int fpcsr_pending(unsigned int __user *fpcsr)
 135 {
 136         int err, sig = 0;
 137         unsigned int csr, enabled;
 138
 139         err = __get_user(csr, fpcsr);
 140         enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
 141         /*
 142          * If the signal handler set some FPU exceptions, clear it and
 143          * send SIGFPE.
 144          */
 145         if (csr & enabled) {
 146                 csr &= ~enabled;
 147                 err |= __put_user(csr, fpcsr);
 148                 sig = SIGFPE;
 149         }
 150         return err ?: sig;
 151 }
 152
 153 static int
 154 check_and_restore_fp_context(struct sigcontext __user *sc)
 155 {
 156         int err, sig;
 157
 158         err = sig = fpcsr_pending(&sc->sc_fpc_csr);
 159         if (err > 0)
 160                 err = 0;
 161         err |= protected_restore_fp_context(sc);
 162         return err ?: sig;
 163 }
 164
 165 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 166 {
 167         unsigned int used_math;
 168         unsigned long treg;
 169         int err = 0;
 170         int i;
 171
 172         /* Always make any pending restarted system calls return -EINTR */
 173         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 174
 175         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 176
 177 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 178         err |= __get_user(regs->acx, &sc->sc_acx);
 179 #endif
 180         err |= __get_user(regs->hi, &sc->sc_mdhi);
 181         err |= __get_user(regs->lo, &sc->sc_mdlo);
 182         if (cpu_has_dsp) {
 183                 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 184                 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 185                 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 186                 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 187                 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 188                 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 189                 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 190         }
 191
 192         for (i = 1; i < 32; i++)
 193                 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 194
 195         err |= __get_user(used_math, &sc->sc_used_math);
 196         conditional_used_math(used_math);
 197
 198         if (used_math) {
 199                 /* restore fpu context if we have used it before */
 200                 if (!err)
 201                         err = check_and_restore_fp_context(sc);
 202         } else {
 203                 /* signal handler may have used FPU.  Give it up. */
 204                 lose_fpu(0);
 205         }
 206
 207         return err;
 208 }
 209
 210 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 211                           size_t frame_size)
 212 {
 213         unsigned long sp;
 214
 215         /* Default to using normal stack */
 216         sp = regs->regs[29];
 217
 218         /*
 219          * FPU emulator may have it's own trampoline active just
 220          * above the user stack, 16-bytes before the next lowest
 221          * 16 byte boundary.  Try to avoid trashing it.
 222          */
 223         sp -= 32;
 224
 225         /* This is the X/Open sanctioned signal stack switching.  */
 226         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 227                 sp = current->sas_ss_sp + current->sas_ss_size;
 228
 229         return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
 230 }
 231
 232 /*
 233  * Atomically swap in the new signal mask, and wait for a signal.
 234  */
 235
 236 #ifdef CONFIG_TRAD_SIGNALS
 237 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
 238 {
 239         sigset_t newset;
 240         sigset_t __user *uset;
 241
 242         uset = (sigset_t __user *) regs.regs[4];
 243         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
 244                 return -EFAULT;
 245         sigdelsetmask(&newset, ~_BLOCKABLE);
 246
 247         spin_lock_irq(&current->sighand->siglock);
 248         current->saved_sigmask = current->blocked;
 249         current->blocked = newset;
 250         recalc_sigpending();
 251         spin_unlock_irq(&current->sighand->siglock);
 252
 253         current->state = TASK_INTERRUPTIBLE;
 254         schedule();
 255         set_thread_flag(TIF_RESTORE_SIGMASK);
 256         return -ERESTARTNOHAND;
 257 }
 258 #endif
 259
 260 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 261 {
 262         sigset_t newset;
 263         sigset_t __user *unewset;
 264         size_t sigsetsize;
 265
 266         /* XXX Don't preclude handling different sized sigset_t's.  */
 267         sigsetsize = regs.regs[5];
 268         if (sigsetsize != sizeof(sigset_t))
 269                 return -EINVAL;
 270
 271         unewset = (sigset_t __user *) regs.regs[4];
 272         if (copy_from_user(&newset, unewset, sizeof(newset)))
 273                 return -EFAULT;
 274         sigdelsetmask(&newset, ~_BLOCKABLE);
 275
 276         spin_lock_irq(&current->sighand->siglock);
 277         current->saved_sigmask = current->blocked;
 278         current->blocked = newset;
 279         recalc_sigpending();
 280         spin_unlock_irq(&current->sighand->siglock);
 281
 282         current->state = TASK_INTERRUPTIBLE;
 283         schedule();
 284         set_thread_flag(TIF_RESTORE_SIGMASK);
 285         return -ERESTARTNOHAND;
 286 }
 287
 288 #ifdef CONFIG_TRAD_SIGNALS
 289 asmlinkage int sys_sigaction(int sig, const struct sigaction __user *act,
 290         struct sigaction __user *oact)
 291 {
 292         struct k_sigaction new_ka, old_ka;
 293         int ret;
 294         int err = 0;
 295
 296         if (act) {
 297                 old_sigset_t mask;
 298
 299                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 300                         return -EFAULT;
 301                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 302                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 303                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 304                 if (err)
 305                         return -EFAULT;
 306
 307                 siginitset(&new_ka.sa.sa_mask, mask);
 308         }
 309
 310         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 311
 312         if (!ret && oact) {
 313                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 314                         return -EFAULT;
 315                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 316                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 317                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 318                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 319                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 320                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 321                 if (err)
 322                         return -EFAULT;
 323         }
 324
 325         return ret;
 326 }
 327 #endif
 328
 329 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 330 {
 331         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
 332         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
 333         unsigned long usp = regs.regs[29];
 334
 335         return do_sigaltstack(uss, uoss, usp);
 336 }
 337
 338 #ifdef CONFIG_TRAD_SIGNALS
 339 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 340 {
 341         struct sigframe __user *frame;
 342         sigset_t blocked;
 343         int sig;
 344
 345         frame = (struct sigframe __user *) regs.regs[29];
 346         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 347                 goto badframe;
 348         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 349                 goto badframe;
 350
 351         sigdelsetmask(&blocked, ~_BLOCKABLE);
 352         spin_lock_irq(&current->sighand->siglock);
 353         current->blocked = blocked;
 354         recalc_sigpending();
 355         spin_unlock_irq(&current->sighand->siglock);
 356
 357         sig = restore_sigcontext(&regs, &frame->sf_sc);
 358         if (sig < 0)
 359                 goto badframe;
 360         else if (sig)
 361                 force_sig(sig, current);
 362
 363         /*
 364          * Don't let your children do this ...
 365          */
 366         __asm__ __volatile__(
 367                 "move\t$29, %0\n\t"
 368                 "j\tsyscall_exit"
 369                 :/* no outputs */
 370                 :"r" (&regs));
 371         /* Unreached */
 372
 373 badframe:
 374         force_sig(SIGSEGV, current);
 375 }
 376 #endif /* CONFIG_TRAD_SIGNALS */
 377
 378 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 379 {
 380         struct rt_sigframe __user *frame;
 381         sigset_t set;
 382         int sig;
 383
 384         frame = (struct rt_sigframe __user *) regs.regs[29];
 385         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 386                 goto badframe;
 387         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 388                 goto badframe;
 389
 390         sigdelsetmask(&set, ~_BLOCKABLE);
 391         spin_lock_irq(&current->sighand->siglock);
 392         current->blocked = set;
 393         recalc_sigpending();
 394         spin_unlock_irq(&current->sighand->siglock);
 395
 396         sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 397         if (sig < 0)
 398                 goto badframe;
 399         else if (sig)
 400                 force_sig(sig, current);
 401
 402         /* It is more difficult to avoid calling this function than to
 403            call it and ignore errors.  */
 404         do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
 405
 406         /*
 407          * Don't let your children do this ...
 408          */
 409         __asm__ __volatile__(
 410                 "move\t$29, %0\n\t"
 411                 "j\tsyscall_exit"
 412                 :/* no outputs */
 413                 :"r" (&regs));
 414         /* Unreached */
 415
 416 badframe:
 417         force_sig(SIGSEGV, current);
 418 }
 419
 420 #ifdef CONFIG_TRAD_SIGNALS
 421 static int setup_frame(void *sig_return, struct k_sigaction *ka,
 422                        struct pt_regs *regs, int signr, sigset_t *set)
 423 {
 424         struct sigframe __user *frame;
 425         int err = 0;
 426
 427         frame = get_sigframe(ka, regs, sizeof(*frame));
 428         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 429                 goto give_sigsegv;
 430
 431         err |= setup_sigcontext(regs, &frame->sf_sc);
 432         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 433         if (err)
 434                 goto give_sigsegv;
 435
 436         /*
 437          * Arguments to signal handler:
 438          *
 439          *   a0 = signal number
 440          *   a1 = 0 (should be cause)
 441          *   a2 = pointer to struct sigcontext
 442          *
 443          * $25 and c0_epc point to the signal handler, $29 points to the
 444          * struct sigframe.
 445          */
 446         regs->regs[ 4] = signr;
 447         regs->regs[ 5] = 0;
 448         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 449         regs->regs[29] = (unsigned long) frame;
 450         regs->regs[31] = (unsigned long) sig_return;
 451         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 452
 453         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 454                current->comm, current->pid,
 455                frame, regs->cp0_epc, regs->regs[31]);
 456         return 0;
 457
 458 give_sigsegv:
 459         force_sigsegv(signr, current);
 460         return -EFAULT;
 461 }
 462 #endif
 463
 464 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
 465                           struct pt_regs *regs, int signr, sigset_t *set,
 466                           siginfo_t *info)
 467 {
 468         struct rt_sigframe __user *frame;
 469         int err = 0;
 470
 471         frame = get_sigframe(ka, regs, sizeof(*frame));
 472         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 473                 goto give_sigsegv;
 474
 475         /* Create siginfo.  */
 476         err |= copy_siginfo_to_user(&frame->rs_info, info);
 477
 478         /* Create the ucontext.  */
 479         err |= __put_user(0, &frame->rs_uc.uc_flags);
 480         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 481         err |= __put_user((void __user *)current->sas_ss_sp,
 482                           &frame->rs_uc.uc_stack.ss_sp);
 483         err |= __put_user(sas_ss_flags(regs->regs[29]),
 484                           &frame->rs_uc.uc_stack.ss_flags);
 485         err |= __put_user(current->sas_ss_size,
 486                           &frame->rs_uc.uc_stack.ss_size);
 487         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 488         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 489
 490         if (err)
 491                 goto give_sigsegv;
 492
 493         /*
 494          * Arguments to signal handler:
 495          *
 496          *   a0 = signal number
 497          *   a1 = 0 (should be cause)
 498          *   a2 = pointer to ucontext
 499          *
 500          * $25 and c0_epc point to the signal handler, $29 points to
 501          * the struct rt_sigframe.
 502          */
 503         regs->regs[ 4] = signr;
 504         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 505         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 506         regs->regs[29] = (unsigned long) frame;
 507         regs->regs[31] = (unsigned long) sig_return;
 508         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 509
 510         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 511                current->comm, current->pid,
 512                frame, regs->cp0_epc, regs->regs[31]);
 513
 514         return 0;
 515
 516 give_sigsegv:
 517         force_sigsegv(signr, current);
 518         return -EFAULT;
 519 }
 520
 521 struct mips_abi mips_abi = {
 522 #ifdef CONFIG_TRAD_SIGNALS
 523         .setup_frame    = setup_frame,
 524         .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
 525 #endif
 526         .setup_rt_frame = setup_rt_frame,
 527         .rt_signal_return_offset =
 528                 offsetof(struct mips_vdso, rt_signal_trampoline),
 529         .restart        = __NR_restart_syscall
 530 };
 531
 532 static int handle_signal(unsigned long sig, siginfo_t *info,
 533         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 534 {
 535         int ret;
 536         struct mips_abi *abi = current->thread.abi;
 537         void *vdso = current->mm->context.vdso;
 538
 539         if (regs->regs[0]) {
 540                 switch(regs->regs[2]) {
 541                 case ERESTART_RESTARTBLOCK:
 542                 case ERESTARTNOHAND:
 543                         regs->regs[2] = EINTR;
 544                         break;
 545                 case ERESTARTSYS:
 546                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 547                                 regs->regs[2] = EINTR;
 548                                 break;
 549                         }
 550                 /* fallthrough */
 551                 case ERESTARTNOINTR:
 552                         regs->regs[7] = regs->regs[26];
 553                         regs->regs[2] = regs->regs[0];
 554                         regs->cp0_epc -= 4;
 555                 }
 556
 557                 regs->regs[0] = 0;              /* Don't deal with this again.  */
 558         }
 559
 560         if (sig_uses_siginfo(ka))
 561                 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
 562                                           ka, regs, sig, oldset, info);
 563         else
 564                 ret = abi->setup_frame(vdso + abi->signal_return_offset,
 565                                        ka, regs, sig, oldset);
 566
 567         if (ret)
 568                 return ret;
 569
 570         spin_lock_irq(&current->sighand->siglock);
 571         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 572         if (!(ka->sa.sa_flags & SA_NODEFER))
 573                 sigaddset(&current->blocked,sig);
 574         recalc_sigpending();
 575         spin_unlock_irq(&current->sighand->siglock);
 576
 577         return ret;
 578 }
 579
 580 static void do_signal(struct pt_regs *regs)
 581 {
 582         struct k_sigaction ka;
 583         sigset_t *oldset;
 584         siginfo_t info;
 585         int signr;
 586
 587         /*
 588          * We want the common case to go fast, which is why we may in certain
 589          * cases get here from kernel mode. Just return without doing anything
 590          * if so.
 591          */
 592         if (!user_mode(regs))
 593                 return;
 594
 595         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 596                 oldset = &current->saved_sigmask;
 597         else
 598                 oldset = &current->blocked;
 599
 600         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 601         if (signr > 0) {
 602                 /* Whee!  Actually deliver the signal.  */
 603                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 604                         /*
 605                          * A signal was successfully delivered; the saved
 606                          * sigmask will have been stored in the signal frame,
 607                          * and will be restored by sigreturn, so we can simply
 608                          * clear the TIF_RESTORE_SIGMASK flag.
 609                          */
 610                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 611                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 612                 }
 613
 614                 return;
 615         }
 616
 617         if (regs->regs[0]) {
 618                 if (regs->regs[2] == ERESTARTNOHAND ||
 619                     regs->regs[2] == ERESTARTSYS ||
 620                     regs->regs[2] == ERESTARTNOINTR) {
 621                         regs->regs[2] = regs->regs[0];
 622                         regs->regs[7] = regs->regs[26];
 623                         regs->cp0_epc -= 4;
 624                 }
 625                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
 626                         regs->regs[2] = current->thread.abi->restart;
 627                         regs->regs[7] = regs->regs[26];
 628                         regs->cp0_epc -= 4;
 629                 }
 630                 regs->regs[0] = 0;      /* Don't deal with this again.  */
 631         }
 632
 633         /*
 634          * If there's no signal to deliver, we just put the saved sigmask
 635          * back
 636          */
 637         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 638                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 639                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 640         }
 641 }
 642
 643 /*
 644  * notification of userspace execution resumption
 645  * - triggered by the TIF_WORK_MASK flags
 646  */
 647 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 648         __u32 thread_info_flags)
 649 {
 650         /* deal with pending signal delivery */
 651         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 652                 do_signal(regs);
 653 }