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/irqflags.h>
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/personality.h>
  15 #include <linux/smp.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 #include <linux/syscalls.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/tracehook.h>
  26
  27 #include <asm/abi.h>
  28 #include <asm/asm.h>
  29 #include <linux/bitops.h>
  30 #include <asm/cacheflush.h>
  31 #include <asm/fpu.h>
  32 #include <asm/sim.h>
  33 #include <asm/ucontext.h>
  34 #include <asm/cpu-features.h>
  35 #include <asm/war.h>
  36 #include <asm/vdso.h>
  37 #include <asm/dsp.h>
  38
  39 #include "signal-common.h"
  40
  41 static int (*save_fp_context)(struct sigcontext __user *sc);
  42 static int (*restore_fp_context)(struct sigcontext __user *sc);
  43
  44 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
  45 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
  46
  47 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
  48 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
  49
  50 struct sigframe {
  51         u32 sf_ass[4];          /* argument save space for o32 */
  52         u32 sf_pad[2];          /* Was: signal trampoline */
  53         struct sigcontext sf_sc;
  54         sigset_t sf_mask;
  55 };
  56
  57 struct rt_sigframe {
  58         u32 rs_ass[4];          /* argument save space for o32 */
  59         u32 rs_pad[2];          /* Was: signal trampoline */
  60         struct siginfo rs_info;
  61         struct ucontext rs_uc;
  62 };
  63
  64 /*
  65  * Helper routines
  66  */
  67 static int protected_save_fp_context(struct sigcontext __user *sc)
  68 {
  69         int err;
  70         while (1) {
  71                 lock_fpu_owner();
  72                 own_fpu_inatomic(1);
  73                 err = save_fp_context(sc); /* this might fail */
  74                 unlock_fpu_owner();
  75                 if (likely(!err))
  76                         break;
  77                 /* touch the sigcontext and try again */
  78                 err = __put_user(0, &sc->sc_fpregs[0]) |
  79                         __put_user(0, &sc->sc_fpregs[31]) |
  80                         __put_user(0, &sc->sc_fpc_csr);
  81                 if (err)
  82                         break;  /* really bad sigcontext */
  83         }
  84         return err;
  85 }
  86
  87 static int protected_restore_fp_context(struct sigcontext __user *sc)
  88 {
  89         int err, tmp __maybe_unused;
  90         while (1) {
  91                 lock_fpu_owner();
  92                 own_fpu_inatomic(0);
  93                 err = restore_fp_context(sc); /* this might fail */
  94                 unlock_fpu_owner();
  95                 if (likely(!err))
  96                         break;
  97                 /* touch the sigcontext and try again */
  98                 err = __get_user(tmp, &sc->sc_fpregs[0]) |
  99                         __get_user(tmp, &sc->sc_fpregs[31]) |
 100                         __get_user(tmp, &sc->sc_fpc_csr);
 101                 if (err)
 102                         break;  /* really bad sigcontext */
 103         }
 104         return err;
 105 }
 106
 107 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 108 {
 109         int err = 0;
 110         int i;
 111         unsigned int used_math;
 112
 113         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 114
 115         err |= __put_user(0, &sc->sc_regs[0]);
 116         for (i = 1; i < 32; i++)
 117                 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
 118
 119 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 120         err |= __put_user(regs->acx, &sc->sc_acx);
 121 #endif
 122         err |= __put_user(regs->hi, &sc->sc_mdhi);
 123         err |= __put_user(regs->lo, &sc->sc_mdlo);
 124         if (cpu_has_dsp) {
 125                 err |= __put_user(mfhi1(), &sc->sc_hi1);
 126                 err |= __put_user(mflo1(), &sc->sc_lo1);
 127                 err |= __put_user(mfhi2(), &sc->sc_hi2);
 128                 err |= __put_user(mflo2(), &sc->sc_lo2);
 129                 err |= __put_user(mfhi3(), &sc->sc_hi3);
 130                 err |= __put_user(mflo3(), &sc->sc_lo3);
 131                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 132         }
 133
 134         used_math = !!used_math();
 135         err |= __put_user(used_math, &sc->sc_used_math);
 136
 137         if (used_math) {
 138                 /*
 139                  * Save FPU state to signal context. Signal handler
 140                  * will "inherit" current FPU state.
 141                  */
 142                 err |= protected_save_fp_context(sc);
 143         }
 144         return err;
 145 }
 146
 147 int fpcsr_pending(unsigned int __user *fpcsr)
 148 {
 149         int err, sig = 0;
 150         unsigned int csr, enabled;
 151
 152         err = __get_user(csr, fpcsr);
 153         enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
 154         /*
 155          * If the signal handler set some FPU exceptions, clear it and
 156          * send SIGFPE.
 157          */
 158         if (csr & enabled) {
 159                 csr &= ~enabled;
 160                 err |= __put_user(csr, fpcsr);
 161                 sig = SIGFPE;
 162         }
 163         return err ?: sig;
 164 }
 165
 166 static int
 167 check_and_restore_fp_context(struct sigcontext __user *sc)
 168 {
 169         int err, sig;
 170
 171         err = sig = fpcsr_pending(&sc->sc_fpc_csr);
 172         if (err > 0)
 173                 err = 0;
 174         err |= protected_restore_fp_context(sc);
 175         return err ?: sig;
 176 }
 177
 178 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 179 {
 180         unsigned int used_math;
 181         unsigned long treg;
 182         int err = 0;
 183         int i;
 184
 185         /* Always make any pending restarted system calls return -EINTR */
 186         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 187
 188         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 189
 190 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 191         err |= __get_user(regs->acx, &sc->sc_acx);
 192 #endif
 193         err |= __get_user(regs->hi, &sc->sc_mdhi);
 194         err |= __get_user(regs->lo, &sc->sc_mdlo);
 195         if (cpu_has_dsp) {
 196                 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 197                 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 198                 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 199                 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 200                 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 201                 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 202                 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 203         }
 204
 205         for (i = 1; i < 32; i++)
 206                 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 207
 208         err |= __get_user(used_math, &sc->sc_used_math);
 209         conditional_used_math(used_math);
 210
 211         if (used_math) {
 212                 /* restore fpu context if we have used it before */
 213                 if (!err)
 214                         err = check_and_restore_fp_context(sc);
 215         } else {
 216                 /* signal handler may have used FPU.  Give it up. */
 217                 lose_fpu(0);
 218         }
 219
 220         return err;
 221 }
 222
 223 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 224                           size_t frame_size)
 225 {
 226         unsigned long sp;
 227
 228         /* Default to using normal stack */
 229         sp = regs->regs[29];
 230
 231         /*
 232          * FPU emulator may have it's own trampoline active just
 233          * above the user stack, 16-bytes before the next lowest
 234          * 16 byte boundary.  Try to avoid trashing it.
 235          */
 236         sp -= 32;
 237
 238         /* This is the X/Open sanctioned signal stack switching.  */
 239         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 240                 sp = current->sas_ss_sp + current->sas_ss_size;
 241
 242         return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
 243 }
 244
 245 /*
 246  * Atomically swap in the new signal mask, and wait for a signal.
 247  */
 248
 249 #ifdef CONFIG_TRAD_SIGNALS
 250 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
 251 {
 252         sigset_t newset;
 253         sigset_t __user *uset;
 254
 255         uset = (sigset_t __user *) regs.regs[4];
 256         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
 257                 return -EFAULT;
 258         sigdelsetmask(&newset, ~_BLOCKABLE);
 259
 260         current->saved_sigmask = current->blocked;
 261         set_current_blocked(&newset);
 262
 263         current->state = TASK_INTERRUPTIBLE;
 264         schedule();
 265         set_thread_flag(TIF_RESTORE_SIGMASK);
 266         return -ERESTARTNOHAND;
 267 }
 268 #endif
 269
 270 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 271 {
 272         sigset_t newset;
 273         sigset_t __user *unewset;
 274         size_t sigsetsize;
 275
 276         /* XXX Don't preclude handling different sized sigset_t's.  */
 277         sigsetsize = regs.regs[5];
 278         if (sigsetsize != sizeof(sigset_t))
 279                 return -EINVAL;
 280
 281         unewset = (sigset_t __user *) regs.regs[4];
 282         if (copy_from_user(&newset, unewset, sizeof(newset)))
 283                 return -EFAULT;
 284         sigdelsetmask(&newset, ~_BLOCKABLE);
 285
 286         current->saved_sigmask = current->blocked;
 287         set_current_blocked(&newset);
 288
 289         current->state = TASK_INTERRUPTIBLE;
 290         schedule();
 291         set_thread_flag(TIF_RESTORE_SIGMASK);
 292         return -ERESTARTNOHAND;
 293 }
 294
 295 #ifdef CONFIG_TRAD_SIGNALS
 296 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 297         struct sigaction __user *, oact)
 298 {
 299         struct k_sigaction new_ka, old_ka;
 300         int ret;
 301         int err = 0;
 302
 303         if (act) {
 304                 old_sigset_t mask;
 305
 306                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 307                         return -EFAULT;
 308                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 309                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 310                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 311                 if (err)
 312                         return -EFAULT;
 313
 314                 siginitset(&new_ka.sa.sa_mask, mask);
 315         }
 316
 317         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 318
 319         if (!ret && oact) {
 320                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 321                         return -EFAULT;
 322                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 323                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 324                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 325                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 326                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 327                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 328                 if (err)
 329                         return -EFAULT;
 330         }
 331
 332         return ret;
 333 }
 334 #endif
 335
 336 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 337 {
 338         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
 339         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
 340         unsigned long usp = regs.regs[29];
 341
 342         return do_sigaltstack(uss, uoss, usp);
 343 }
 344
 345 #ifdef CONFIG_TRAD_SIGNALS
 346 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 347 {
 348         struct sigframe __user *frame;
 349         sigset_t blocked;
 350         int sig;
 351
 352         frame = (struct sigframe __user *) regs.regs[29];
 353         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 354                 goto badframe;
 355         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 356                 goto badframe;
 357
 358         sigdelsetmask(&blocked, ~_BLOCKABLE);
 359         set_current_blocked(&blocked);
 360
 361         sig = restore_sigcontext(&regs, &frame->sf_sc);
 362         if (sig < 0)
 363                 goto badframe;
 364         else if (sig)
 365                 force_sig(sig, current);
 366
 367         /*
 368          * Don't let your children do this ...
 369          */
 370         __asm__ __volatile__(
 371                 "move\t$29, %0\n\t"
 372                 "j\tsyscall_exit"
 373                 :/* no outputs */
 374                 :"r" (&regs));
 375         /* Unreached */
 376
 377 badframe:
 378         force_sig(SIGSEGV, current);
 379 }
 380 #endif /* CONFIG_TRAD_SIGNALS */
 381
 382 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 383 {
 384         struct rt_sigframe __user *frame;
 385         sigset_t set;
 386         int sig;
 387
 388         frame = (struct rt_sigframe __user *) regs.regs[29];
 389         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 390                 goto badframe;
 391         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 392                 goto badframe;
 393
 394         sigdelsetmask(&set, ~_BLOCKABLE);
 395         set_current_blocked(&set);
 396
 397         sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 398         if (sig < 0)
 399                 goto badframe;
 400         else if (sig)
 401                 force_sig(sig, current);
 402
 403         /* It is more difficult to avoid calling this function than to
 404            call it and ignore errors.  */
 405         do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
 406
 407         /*
 408          * Don't let your children do this ...
 409          */
 410         __asm__ __volatile__(
 411                 "move\t$29, %0\n\t"
 412                 "j\tsyscall_exit"
 413                 :/* no outputs */
 414                 :"r" (&regs));
 415         /* Unreached */
 416
 417 badframe:
 418         force_sig(SIGSEGV, current);
 419 }
 420
 421 #ifdef CONFIG_TRAD_SIGNALS
 422 static int setup_frame(void *sig_return, struct k_sigaction *ka,
 423                        struct pt_regs *regs, int signr, sigset_t *set)
 424 {
 425         struct sigframe __user *frame;
 426         int err = 0;
 427
 428         frame = get_sigframe(ka, regs, sizeof(*frame));
 429         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 430                 goto give_sigsegv;
 431
 432         err |= setup_sigcontext(regs, &frame->sf_sc);
 433         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 434         if (err)
 435                 goto give_sigsegv;
 436
 437         /*
 438          * Arguments to signal handler:
 439          *
 440          *   a0 = signal number
 441          *   a1 = 0 (should be cause)
 442          *   a2 = pointer to struct sigcontext
 443          *
 444          * $25 and c0_epc point to the signal handler, $29 points to the
 445          * struct sigframe.
 446          */
 447         regs->regs[ 4] = signr;
 448         regs->regs[ 5] = 0;
 449         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 450         regs->regs[29] = (unsigned long) frame;
 451         regs->regs[31] = (unsigned long) sig_return;
 452         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 453
 454         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 455                current->comm, current->pid,
 456                frame, regs->cp0_epc, regs->regs[31]);
 457         return 0;
 458
 459 give_sigsegv:
 460         force_sigsegv(signr, current);
 461         return -EFAULT;
 462 }
 463 #endif
 464
 465 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
 466                           struct pt_regs *regs, int signr, sigset_t *set,
 467                           siginfo_t *info)
 468 {
 469         struct rt_sigframe __user *frame;
 470         int err = 0;
 471
 472         frame = get_sigframe(ka, regs, sizeof(*frame));
 473         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 474                 goto give_sigsegv;
 475
 476         /* Create siginfo.  */
 477         err |= copy_siginfo_to_user(&frame->rs_info, info);
 478
 479         /* Create the ucontext.  */
 480         err |= __put_user(0, &frame->rs_uc.uc_flags);
 481         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 482         err |= __put_user((void __user *)current->sas_ss_sp,
 483                           &frame->rs_uc.uc_stack.ss_sp);
 484         err |= __put_user(sas_ss_flags(regs->regs[29]),
 485                           &frame->rs_uc.uc_stack.ss_flags);
 486         err |= __put_user(current->sas_ss_size,
 487                           &frame->rs_uc.uc_stack.ss_size);
 488         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 489         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 490
 491         if (err)
 492                 goto give_sigsegv;
 493
 494         /*
 495          * Arguments to signal handler:
 496          *
 497          *   a0 = signal number
 498          *   a1 = 0 (should be cause)
 499          *   a2 = pointer to ucontext
 500          *
 501          * $25 and c0_epc point to the signal handler, $29 points to
 502          * the struct rt_sigframe.
 503          */
 504         regs->regs[ 4] = signr;
 505         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 506         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 507         regs->regs[29] = (unsigned long) frame;
 508         regs->regs[31] = (unsigned long) sig_return;
 509         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 510
 511         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 512                current->comm, current->pid,
 513                frame, regs->cp0_epc, regs->regs[31]);
 514
 515         return 0;
 516
 517 give_sigsegv:
 518         force_sigsegv(signr, current);
 519         return -EFAULT;
 520 }
 521
 522 struct mips_abi mips_abi = {
 523 #ifdef CONFIG_TRAD_SIGNALS
 524         .setup_frame    = setup_frame,
 525         .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
 526 #endif
 527         .setup_rt_frame = setup_rt_frame,
 528         .rt_signal_return_offset =
 529                 offsetof(struct mips_vdso, rt_signal_trampoline),
 530         .restart        = __NR_restart_syscall
 531 };
 532
 533 static int handle_signal(unsigned long sig, siginfo_t *info,
 534         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 535 {
 536         int ret;
 537         struct mips_abi *abi = current->thread.abi;
 538         void *vdso = current->mm->context.vdso;
 539
 540         if (regs->regs[0]) {
 541                 switch(regs->regs[2]) {
 542                 case ERESTART_RESTARTBLOCK:
 543                 case ERESTARTNOHAND:
 544                         regs->regs[2] = EINTR;
 545                         break;
 546                 case ERESTARTSYS:
 547                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 548                                 regs->regs[2] = EINTR;
 549                                 break;
 550                         }
 551                 /* fallthrough */
 552                 case ERESTARTNOINTR:
 553                         regs->regs[7] = regs->regs[26];
 554                         regs->regs[2] = regs->regs[0];
 555                         regs->cp0_epc -= 4;
 556                 }
 557
 558                 regs->regs[0] = 0;              /* Don't deal with this again.  */
 559         }
 560
 561         if (sig_uses_siginfo(ka))
 562                 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
 563                                           ka, regs, sig, oldset, info);
 564         else
 565                 ret = abi->setup_frame(vdso + abi->signal_return_offset,
 566                                        ka, regs, sig, oldset);
 567
 568         if (ret)
 569                 return ret;
 570
 571         block_sigmask(ka, sig);
 572
 573         return ret;
 574 }
 575
 576 static void do_signal(struct pt_regs *regs)
 577 {
 578         struct k_sigaction ka;
 579         sigset_t *oldset;
 580         siginfo_t info;
 581         int signr;
 582
 583         /*
 584          * We want the common case to go fast, which is why we may in certain
 585          * cases get here from kernel mode. Just return without doing anything
 586          * if so.
 587          */
 588         if (!user_mode(regs))
 589                 return;
 590
 591         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 592                 oldset = &current->saved_sigmask;
 593         else
 594                 oldset = &current->blocked;
 595
 596         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 597         if (signr > 0) {
 598                 /* Whee!  Actually deliver the signal.  */
 599                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 600                         /*
 601                          * A signal was successfully delivered; the saved
 602                          * sigmask will have been stored in the signal frame,
 603                          * and will be restored by sigreturn, so we can simply
 604                          * clear the TIF_RESTORE_SIGMASK flag.
 605                          */
 606                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 607                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 608                 }
 609
 610                 return;
 611         }
 612
 613         if (regs->regs[0]) {
 614                 if (regs->regs[2] == ERESTARTNOHAND ||
 615                     regs->regs[2] == ERESTARTSYS ||
 616                     regs->regs[2] == ERESTARTNOINTR) {
 617                         regs->regs[2] = regs->regs[0];
 618                         regs->regs[7] = regs->regs[26];
 619                         regs->cp0_epc -= 4;
 620                 }
 621                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
 622                         regs->regs[2] = current->thread.abi->restart;
 623                         regs->regs[7] = regs->regs[26];
 624                         regs->cp0_epc -= 4;
 625                 }
 626                 regs->regs[0] = 0;      /* Don't deal with this again.  */
 627         }
 628
 629         /*
 630          * If there's no signal to deliver, we just put the saved sigmask
 631          * back
 632          */
 633         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 634                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 635                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 636         }
 637 }
 638
 639 /*
 640  * notification of userspace execution resumption
 641  * - triggered by the TIF_WORK_MASK flags
 642  */
 643 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 644         __u32 thread_info_flags)
 645 {
 646         local_irq_enable();
 647
 648         /* deal with pending signal delivery */
 649         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 650                 do_signal(regs);
 651
 652         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 653                 clear_thread_flag(TIF_NOTIFY_RESUME);
 654                 tracehook_notify_resume(regs);
 655                 if (current->replacement_session_keyring)
 656                         key_replace_session_keyring();
 657         }
 658 }
 659
 660 #ifdef CONFIG_SMP
 661 static int smp_save_fp_context(struct sigcontext __user *sc)
 662 {
 663         return raw_cpu_has_fpu
 664                ? _save_fp_context(sc)
 665                : fpu_emulator_save_context(sc);
 666 }
 667
 668 static int smp_restore_fp_context(struct sigcontext __user *sc)
 669 {
 670         return raw_cpu_has_fpu
 671                ? _restore_fp_context(sc)
 672                : fpu_emulator_restore_context(sc);
 673 }
 674 #endif
 675
 676 static int signal_setup(void)
 677 {
 678 #ifdef CONFIG_SMP
 679         /* For now just do the cpu_has_fpu check when the functions are invoked */
 680         save_fp_context = smp_save_fp_context;
 681         restore_fp_context = smp_restore_fp_context;
 682 #else
 683         if (cpu_has_fpu) {
 684                 save_fp_context = _save_fp_context;
 685                 restore_fp_context = _restore_fp_context;
 686         } else {
 687                 save_fp_context = fpu_emulator_save_context;
 688                 restore_fp_context = fpu_emulator_restore_context;
 689         }
 690 #endif
 691
 692         return 0;
 693 }
 694
 695 arch_initcall(signal_setup);