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/syscalls.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/tracehook.h>
  25
  26 #include <asm/abi.h>
  27 #include <asm/asm.h>
  28 #include <linux/bitops.h>
  29 #include <asm/cacheflush.h>
  30 #include <asm/fpu.h>
  31 #include <asm/sim.h>
  32 #include <asm/ucontext.h>
  33 #include <asm/cpu-features.h>
  34 #include <asm/war.h>
  35 #include <asm/vdso.h>
  36
  37 #include "signal-common.h"
  38
  39 static int (*save_fp_context)(struct sigcontext __user *sc);
  40 static int (*restore_fp_context)(struct sigcontext __user *sc);
  41
  42 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
  43 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
  44
  45 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
  46 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
  47
  48 struct sigframe {
  49         u32 sf_ass[4];          /* argument save space for o32 */
  50         u32 sf_pad[2];          /* Was: signal trampoline */
  51         struct sigcontext sf_sc;
  52         sigset_t sf_mask;
  53 };
  54
  55 struct rt_sigframe {
  56         u32 rs_ass[4];          /* argument save space for o32 */
  57         u32 rs_pad[2];          /* Was: signal trampoline */
  58         struct siginfo rs_info;
  59         struct ucontext rs_uc;
  60 };
  61
  62 /*
  63  * Helper routines
  64  */
  65 static int protected_save_fp_context(struct sigcontext __user *sc)
  66 {
  67         int err;
  68         while (1) {
  69                 lock_fpu_owner();
  70                 own_fpu_inatomic(1);
  71                 err = save_fp_context(sc); /* this might fail */
  72                 unlock_fpu_owner();
  73                 if (likely(!err))
  74                         break;
  75                 /* touch the sigcontext and try again */
  76                 err = __put_user(0, &sc->sc_fpregs[0]) |
  77                         __put_user(0, &sc->sc_fpregs[31]) |
  78                         __put_user(0, &sc->sc_fpc_csr);
  79                 if (err)
  80                         break;  /* really bad sigcontext */
  81         }
  82         return err;
  83 }
  84
  85 static int protected_restore_fp_context(struct sigcontext __user *sc)
  86 {
  87         int err, tmp;
  88         while (1) {
  89                 lock_fpu_owner();
  90                 own_fpu_inatomic(0);
  91                 err = restore_fp_context(sc); /* this might fail */
  92                 unlock_fpu_owner();
  93                 if (likely(!err))
  94                         break;
  95                 /* touch the sigcontext and try again */
  96                 err = __get_user(tmp, &sc->sc_fpregs[0]) |
  97                         __get_user(tmp, &sc->sc_fpregs[31]) |
  98                         __get_user(tmp, &sc->sc_fpc_csr);
  99                 if (err)
 100                         break;  /* really bad sigcontext */
 101         }
 102         return err;
 103 }
 104
 105 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 106 {
 107         int err = 0;
 108         int i;
 109         unsigned int used_math;
 110
 111         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 112
 113         err |= __put_user(0, &sc->sc_regs[0]);
 114         for (i = 1; i < 32; i++)
 115                 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
 116
 117 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 118         err |= __put_user(regs->acx, &sc->sc_acx);
 119 #endif
 120         err |= __put_user(regs->hi, &sc->sc_mdhi);
 121         err |= __put_user(regs->lo, &sc->sc_mdlo);
 122         if (cpu_has_dsp) {
 123                 err |= __put_user(mfhi1(), &sc->sc_hi1);
 124                 err |= __put_user(mflo1(), &sc->sc_lo1);
 125                 err |= __put_user(mfhi2(), &sc->sc_hi2);
 126                 err |= __put_user(mflo2(), &sc->sc_lo2);
 127                 err |= __put_user(mfhi3(), &sc->sc_hi3);
 128                 err |= __put_user(mflo3(), &sc->sc_lo3);
 129                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 130         }
 131
 132         used_math = !!used_math();
 133         err |= __put_user(used_math, &sc->sc_used_math);
 134
 135         if (used_math) {
 136                 /*
 137                  * Save FPU state to signal context. Signal handler
 138                  * will "inherit" current FPU state.
 139                  */
 140                 err |= protected_save_fp_context(sc);
 141         }
 142         return err;
 143 }
 144
 145 int fpcsr_pending(unsigned int __user *fpcsr)
 146 {
 147         int err, sig = 0;
 148         unsigned int csr, enabled;
 149
 150         err = __get_user(csr, fpcsr);
 151         enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
 152         /*
 153          * If the signal handler set some FPU exceptions, clear it and
 154          * send SIGFPE.
 155          */
 156         if (csr & enabled) {
 157                 csr &= ~enabled;
 158                 err |= __put_user(csr, fpcsr);
 159                 sig = SIGFPE;
 160         }
 161         return err ?: sig;
 162 }
 163
 164 static int
 165 check_and_restore_fp_context(struct sigcontext __user *sc)
 166 {
 167         int err, sig;
 168
 169         err = sig = fpcsr_pending(&sc->sc_fpc_csr);
 170         if (err > 0)
 171                 err = 0;
 172         err |= protected_restore_fp_context(sc);
 173         return err ?: sig;
 174 }
 175
 176 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 177 {
 178         unsigned int used_math;
 179         unsigned long treg;
 180         int err = 0;
 181         int i;
 182
 183         /* Always make any pending restarted system calls return -EINTR */
 184         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 185
 186         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 187
 188 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 189         err |= __get_user(regs->acx, &sc->sc_acx);
 190 #endif
 191         err |= __get_user(regs->hi, &sc->sc_mdhi);
 192         err |= __get_user(regs->lo, &sc->sc_mdlo);
 193         if (cpu_has_dsp) {
 194                 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 195                 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 196                 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 197                 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 198                 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 199                 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 200                 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 201         }
 202
 203         for (i = 1; i < 32; i++)
 204                 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 205
 206         err |= __get_user(used_math, &sc->sc_used_math);
 207         conditional_used_math(used_math);
 208
 209         if (used_math) {
 210                 /* restore fpu context if we have used it before */
 211                 if (!err)
 212                         err = check_and_restore_fp_context(sc);
 213         } else {
 214                 /* signal handler may have used FPU.  Give it up. */
 215                 lose_fpu(0);
 216         }
 217
 218         return err;
 219 }
 220
 221 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 222                           size_t frame_size)
 223 {
 224         unsigned long sp;
 225
 226         /* Default to using normal stack */
 227         sp = regs->regs[29];
 228
 229         /*
 230          * FPU emulator may have it's own trampoline active just
 231          * above the user stack, 16-bytes before the next lowest
 232          * 16 byte boundary.  Try to avoid trashing it.
 233          */
 234         sp -= 32;
 235
 236         /* This is the X/Open sanctioned signal stack switching.  */
 237         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 238                 sp = current->sas_ss_sp + current->sas_ss_size;
 239
 240         return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
 241 }
 242
 243 /*
 244  * Atomically swap in the new signal mask, and wait for a signal.
 245  */
 246
 247 #ifdef CONFIG_TRAD_SIGNALS
 248 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
 249 {
 250         sigset_t newset;
 251         sigset_t __user *uset;
 252
 253         uset = (sigset_t __user *) regs.regs[4];
 254         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
 255                 return -EFAULT;
 256         sigdelsetmask(&newset, ~_BLOCKABLE);
 257
 258         spin_lock_irq(&current->sighand->siglock);
 259         current->saved_sigmask = current->blocked;
 260         current->blocked = newset;
 261         recalc_sigpending();
 262         spin_unlock_irq(&current->sighand->siglock);
 263
 264         current->state = TASK_INTERRUPTIBLE;
 265         schedule();
 266         set_thread_flag(TIF_RESTORE_SIGMASK);
 267         return -ERESTARTNOHAND;
 268 }
 269 #endif
 270
 271 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 272 {
 273         sigset_t newset;
 274         sigset_t __user *unewset;
 275         size_t sigsetsize;
 276
 277         /* XXX Don't preclude handling different sized sigset_t's.  */
 278         sigsetsize = regs.regs[5];
 279         if (sigsetsize != sizeof(sigset_t))
 280                 return -EINVAL;
 281
 282         unewset = (sigset_t __user *) regs.regs[4];
 283         if (copy_from_user(&newset, unewset, sizeof(newset)))
 284                 return -EFAULT;
 285         sigdelsetmask(&newset, ~_BLOCKABLE);
 286
 287         spin_lock_irq(&current->sighand->siglock);
 288         current->saved_sigmask = current->blocked;
 289         current->blocked = newset;
 290         recalc_sigpending();
 291         spin_unlock_irq(&current->sighand->siglock);
 292
 293         current->state = TASK_INTERRUPTIBLE;
 294         schedule();
 295         set_thread_flag(TIF_RESTORE_SIGMASK);
 296         return -ERESTARTNOHAND;
 297 }
 298
 299 #ifdef CONFIG_TRAD_SIGNALS
 300 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 301         struct sigaction __user *, oact)
 302 {
 303         struct k_sigaction new_ka, old_ka;
 304         int ret;
 305         int err = 0;
 306
 307         if (act) {
 308                 old_sigset_t mask;
 309
 310                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 311                         return -EFAULT;
 312                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 313                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 314                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 315                 if (err)
 316                         return -EFAULT;
 317
 318                 siginitset(&new_ka.sa.sa_mask, mask);
 319         }
 320
 321         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 322
 323         if (!ret && oact) {
 324                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 325                         return -EFAULT;
 326                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 327                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 328                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 329                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 330                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 331                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 332                 if (err)
 333                         return -EFAULT;
 334         }
 335
 336         return ret;
 337 }
 338 #endif
 339
 340 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 341 {
 342         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
 343         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
 344         unsigned long usp = regs.regs[29];
 345
 346         return do_sigaltstack(uss, uoss, usp);
 347 }
 348
 349 #ifdef CONFIG_TRAD_SIGNALS
 350 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 351 {
 352         struct sigframe __user *frame;
 353         sigset_t blocked;
 354         int sig;
 355
 356         frame = (struct sigframe __user *) regs.regs[29];
 357         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 358                 goto badframe;
 359         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 360                 goto badframe;
 361
 362         sigdelsetmask(&blocked, ~_BLOCKABLE);
 363         spin_lock_irq(&current->sighand->siglock);
 364         current->blocked = blocked;
 365         recalc_sigpending();
 366         spin_unlock_irq(&current->sighand->siglock);
 367
 368         sig = restore_sigcontext(&regs, &frame->sf_sc);
 369         if (sig < 0)
 370                 goto badframe;
 371         else if (sig)
 372                 force_sig(sig, current);
 373
 374         /*
 375          * Don't let your children do this ...
 376          */
 377         __asm__ __volatile__(
 378                 "move\t$29, %0\n\t"
 379                 "j\tsyscall_exit"
 380                 :/* no outputs */
 381                 :"r" (&regs));
 382         /* Unreached */
 383
 384 badframe:
 385         force_sig(SIGSEGV, current);
 386 }
 387 #endif /* CONFIG_TRAD_SIGNALS */
 388
 389 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 390 {
 391         struct rt_sigframe __user *frame;
 392         sigset_t set;
 393         stack_t st;
 394         int sig;
 395
 396         frame = (struct rt_sigframe __user *) regs.regs[29];
 397         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 398                 goto badframe;
 399         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 400                 goto badframe;
 401
 402         sigdelsetmask(&set, ~_BLOCKABLE);
 403         spin_lock_irq(&current->sighand->siglock);
 404         current->blocked = set;
 405         recalc_sigpending();
 406         spin_unlock_irq(&current->sighand->siglock);
 407
 408         sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 409         if (sig < 0)
 410                 goto badframe;
 411         else if (sig)
 412                 force_sig(sig, current);
 413
 414         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 415                 goto badframe;
 416         /* It is more difficult to avoid calling this function than to
 417            call it and ignore errors.  */
 418         do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
 419
 420         /*
 421          * Don't let your children do this ...
 422          */
 423         __asm__ __volatile__(
 424                 "move\t$29, %0\n\t"
 425                 "j\tsyscall_exit"
 426                 :/* no outputs */
 427                 :"r" (&regs));
 428         /* Unreached */
 429
 430 badframe:
 431         force_sig(SIGSEGV, current);
 432 }
 433
 434 #ifdef CONFIG_TRAD_SIGNALS
 435 static int setup_frame(void *sig_return, struct k_sigaction *ka,
 436                        struct pt_regs *regs, int signr, sigset_t *set)
 437 {
 438         struct sigframe __user *frame;
 439         int err = 0;
 440
 441         frame = get_sigframe(ka, regs, sizeof(*frame));
 442         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 443                 goto give_sigsegv;
 444
 445         err |= setup_sigcontext(regs, &frame->sf_sc);
 446         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 447         if (err)
 448                 goto give_sigsegv;
 449
 450         /*
 451          * Arguments to signal handler:
 452          *
 453          *   a0 = signal number
 454          *   a1 = 0 (should be cause)
 455          *   a2 = pointer to struct sigcontext
 456          *
 457          * $25 and c0_epc point to the signal handler, $29 points to the
 458          * struct sigframe.
 459          */
 460         regs->regs[ 4] = signr;
 461         regs->regs[ 5] = 0;
 462         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 463         regs->regs[29] = (unsigned long) frame;
 464         regs->regs[31] = (unsigned long) sig_return;
 465         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 466
 467         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 468                current->comm, current->pid,
 469                frame, regs->cp0_epc, regs->regs[31]);
 470         return 0;
 471
 472 give_sigsegv:
 473         force_sigsegv(signr, current);
 474         return -EFAULT;
 475 }
 476 #endif
 477
 478 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
 479                           struct pt_regs *regs, int signr, sigset_t *set,
 480                           siginfo_t *info)
 481 {
 482         struct rt_sigframe __user *frame;
 483         int err = 0;
 484
 485         frame = get_sigframe(ka, regs, sizeof(*frame));
 486         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 487                 goto give_sigsegv;
 488
 489         /* Create siginfo.  */
 490         err |= copy_siginfo_to_user(&frame->rs_info, info);
 491
 492         /* Create the ucontext.  */
 493         err |= __put_user(0, &frame->rs_uc.uc_flags);
 494         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 495         err |= __put_user((void __user *)current->sas_ss_sp,
 496                           &frame->rs_uc.uc_stack.ss_sp);
 497         err |= __put_user(sas_ss_flags(regs->regs[29]),
 498                           &frame->rs_uc.uc_stack.ss_flags);
 499         err |= __put_user(current->sas_ss_size,
 500                           &frame->rs_uc.uc_stack.ss_size);
 501         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 502         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 503
 504         if (err)
 505                 goto give_sigsegv;
 506
 507         /*
 508          * Arguments to signal handler:
 509          *
 510          *   a0 = signal number
 511          *   a1 = 0 (should be cause)
 512          *   a2 = pointer to ucontext
 513          *
 514          * $25 and c0_epc point to the signal handler, $29 points to
 515          * the struct rt_sigframe.
 516          */
 517         regs->regs[ 4] = signr;
 518         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 519         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 520         regs->regs[29] = (unsigned long) frame;
 521         regs->regs[31] = (unsigned long) sig_return;
 522         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 523
 524         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 525                current->comm, current->pid,
 526                frame, regs->cp0_epc, regs->regs[31]);
 527
 528         return 0;
 529
 530 give_sigsegv:
 531         force_sigsegv(signr, current);
 532         return -EFAULT;
 533 }
 534
 535 struct mips_abi mips_abi = {
 536 #ifdef CONFIG_TRAD_SIGNALS
 537         .setup_frame    = setup_frame,
 538         .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
 539 #endif
 540         .setup_rt_frame = setup_rt_frame,
 541         .rt_signal_return_offset =
 542                 offsetof(struct mips_vdso, rt_signal_trampoline),
 543         .restart        = __NR_restart_syscall
 544 };
 545
 546 static int handle_signal(unsigned long sig, siginfo_t *info,
 547         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 548 {
 549         int ret;
 550         struct mips_abi *abi = current->thread.abi;
 551         void *vdso = current->mm->context.vdso;
 552
 553         switch(regs->regs[0]) {
 554         case ERESTART_RESTARTBLOCK:
 555         case ERESTARTNOHAND:
 556                 regs->regs[2] = EINTR;
 557                 break;
 558         case ERESTARTSYS:
 559                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 560                         regs->regs[2] = EINTR;
 561                         break;
 562                 }
 563         /* fallthrough */
 564         case ERESTARTNOINTR:            /* Userland will reload $v0.  */
 565                 regs->regs[7] = regs->regs[26];
 566                 regs->cp0_epc -= 8;
 567         }
 568
 569         regs->regs[0] = 0;              /* Don't deal with this again.  */
 570
 571         if (sig_uses_siginfo(ka))
 572                 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
 573                                           ka, regs, sig, oldset, info);
 574         else
 575                 ret = abi->setup_frame(vdso + abi->signal_return_offset,
 576                                        ka, regs, sig, oldset);
 577
 578         spin_lock_irq(&current->sighand->siglock);
 579         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 580         if (!(ka->sa.sa_flags & SA_NODEFER))
 581                 sigaddset(&current->blocked, sig);
 582         recalc_sigpending();
 583         spin_unlock_irq(&current->sighand->siglock);
 584
 585         return ret;
 586 }
 587
 588 static void do_signal(struct pt_regs *regs)
 589 {
 590         struct k_sigaction ka;
 591         sigset_t *oldset;
 592         siginfo_t info;
 593         int signr;
 594
 595         /*
 596          * We want the common case to go fast, which is why we may in certain
 597          * cases get here from kernel mode. Just return without doing anything
 598          * if so.
 599          */
 600         if (!user_mode(regs))
 601                 return;
 602
 603         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 604                 oldset = &current->saved_sigmask;
 605         else
 606                 oldset = &current->blocked;
 607
 608         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 609         if (signr > 0) {
 610                 /* Whee!  Actually deliver the signal.  */
 611                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 612                         /*
 613                          * A signal was successfully delivered; the saved
 614                          * sigmask will have been stored in the signal frame,
 615                          * and will be restored by sigreturn, so we can simply
 616                          * clear the TIF_RESTORE_SIGMASK flag.
 617                          */
 618                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 619                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 620                 }
 621
 622                 return;
 623         }
 624
 625         /*
 626          * Who's code doesn't conform to the restartable syscall convention
 627          * dies here!!!  The li instruction, a single machine instruction,
 628          * must directly be followed by the syscall instruction.
 629          */
 630         if (regs->regs[0]) {
 631                 if (regs->regs[2] == ERESTARTNOHAND ||
 632                     regs->regs[2] == ERESTARTSYS ||
 633                     regs->regs[2] == ERESTARTNOINTR) {
 634                         regs->regs[7] = regs->regs[26];
 635                         regs->cp0_epc -= 8;
 636                 }
 637                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
 638                         regs->regs[2] = current->thread.abi->restart;
 639                         regs->regs[7] = regs->regs[26];
 640                         regs->cp0_epc -= 4;
 641                 }
 642                 regs->regs[0] = 0;      /* Don't deal with this again.  */
 643         }
 644
 645         /*
 646          * If there's no signal to deliver, we just put the saved sigmask
 647          * back
 648          */
 649         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 650                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 651                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 652         }
 653 }
 654
 655 /*
 656  * notification of userspace execution resumption
 657  * - triggered by the TIF_WORK_MASK flags
 658  */
 659 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 660         __u32 thread_info_flags)
 661 {
 662         /* deal with pending signal delivery */
 663         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 664                 do_signal(regs);
 665
 666         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 667                 clear_thread_flag(TIF_NOTIFY_RESUME);
 668                 tracehook_notify_resume(regs);
 669                 if (current->replacement_session_keyring)
 670                         key_replace_session_keyring();
 671         }
 672 }
 673
 674 #ifdef CONFIG_SMP
 675 static int smp_save_fp_context(struct sigcontext __user *sc)
 676 {
 677         return raw_cpu_has_fpu
 678                ? _save_fp_context(sc)
 679                : fpu_emulator_save_context(sc);
 680 }
 681
 682 static int smp_restore_fp_context(struct sigcontext __user *sc)
 683 {
 684         return raw_cpu_has_fpu
 685                ? _restore_fp_context(sc)
 686                : fpu_emulator_restore_context(sc);
 687 }
 688 #endif
 689
 690 static int signal_setup(void)
 691 {
 692 #ifdef CONFIG_SMP
 693         /* For now just do the cpu_has_fpu check when the functions are invoked */
 694         save_fp_context = smp_save_fp_context;
 695         restore_fp_context = smp_restore_fp_context;
 696 #else
 697         if (cpu_has_fpu) {
 698                 save_fp_context = _save_fp_context;
 699                 restore_fp_context = _restore_fp_context;
 700         } else {
 701                 save_fp_context = fpu_emulator_save_context;
 702                 restore_fp_context = fpu_emulator_restore_context;
 703         }
 704 #endif
 705
 706         return 0;
 707 }
 708
 709 arch_initcall(signal_setup);