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
  38 #include "signal-common.h"
  39
  40 static int (*save_fp_context)(struct sigcontext __user *sc);
  41 static int (*restore_fp_context)(struct sigcontext __user *sc);
  42
  43 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
  44 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
  45
  46 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
  47 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
  48
  49 struct sigframe {
  50         u32 sf_ass[4];          /* argument save space for o32 */
  51         u32 sf_pad[2];          /* Was: signal trampoline */
  52         struct sigcontext sf_sc;
  53         sigset_t sf_mask;
  54 };
  55
  56 struct rt_sigframe {
  57         u32 rs_ass[4];          /* argument save space for o32 */
  58         u32 rs_pad[2];          /* Was: signal trampoline */
  59         struct siginfo rs_info;
  60         struct ucontext rs_uc;
  61 };
  62
  63 /*
  64  * Helper routines
  65  */
  66 static int protected_save_fp_context(struct sigcontext __user *sc)
  67 {
  68         int err;
  69         while (1) {
  70                 lock_fpu_owner();
  71                 own_fpu_inatomic(1);
  72                 err = save_fp_context(sc); /* this might fail */
  73                 unlock_fpu_owner();
  74                 if (likely(!err))
  75                         break;
  76                 /* touch the sigcontext and try again */
  77                 err = __put_user(0, &sc->sc_fpregs[0]) |
  78                         __put_user(0, &sc->sc_fpregs[31]) |
  79                         __put_user(0, &sc->sc_fpc_csr);
  80                 if (err)
  81                         break;  /* really bad sigcontext */
  82         }
  83         return err;
  84 }
  85
  86 static int protected_restore_fp_context(struct sigcontext __user *sc)
  87 {
  88         int err, tmp __maybe_unused;
  89         while (1) {
  90                 lock_fpu_owner();
  91                 own_fpu_inatomic(0);
  92                 err = restore_fp_context(sc); /* this might fail */
  93                 unlock_fpu_owner();
  94                 if (likely(!err))
  95                         break;
  96                 /* touch the sigcontext and try again */
  97                 err = __get_user(tmp, &sc->sc_fpregs[0]) |
  98                         __get_user(tmp, &sc->sc_fpregs[31]) |
  99                         __get_user(tmp, &sc->sc_fpc_csr);
 100                 if (err)
 101                         break;  /* really bad sigcontext */
 102         }
 103         return err;
 104 }
 105
 106 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 107 {
 108         int err = 0;
 109         int i;
 110         unsigned int used_math;
 111
 112         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 113
 114         err |= __put_user(0, &sc->sc_regs[0]);
 115         for (i = 1; i < 32; i++)
 116                 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
 117
 118 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 119         err |= __put_user(regs->acx, &sc->sc_acx);
 120 #endif
 121         err |= __put_user(regs->hi, &sc->sc_mdhi);
 122         err |= __put_user(regs->lo, &sc->sc_mdlo);
 123         if (cpu_has_dsp) {
 124                 err |= __put_user(mfhi1(), &sc->sc_hi1);
 125                 err |= __put_user(mflo1(), &sc->sc_lo1);
 126                 err |= __put_user(mfhi2(), &sc->sc_hi2);
 127                 err |= __put_user(mflo2(), &sc->sc_lo2);
 128                 err |= __put_user(mfhi3(), &sc->sc_hi3);
 129                 err |= __put_user(mflo3(), &sc->sc_lo3);
 130                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 131         }
 132
 133         used_math = !!used_math();
 134         err |= __put_user(used_math, &sc->sc_used_math);
 135
 136         if (used_math) {
 137                 /*
 138                  * Save FPU state to signal context. Signal handler
 139                  * will "inherit" current FPU state.
 140                  */
 141                 err |= protected_save_fp_context(sc);
 142         }
 143         return err;
 144 }
 145
 146 int fpcsr_pending(unsigned int __user *fpcsr)
 147 {
 148         int err, sig = 0;
 149         unsigned int csr, enabled;
 150
 151         err = __get_user(csr, fpcsr);
 152         enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
 153         /*
 154          * If the signal handler set some FPU exceptions, clear it and
 155          * send SIGFPE.
 156          */
 157         if (csr & enabled) {
 158                 csr &= ~enabled;
 159                 err |= __put_user(csr, fpcsr);
 160                 sig = SIGFPE;
 161         }
 162         return err ?: sig;
 163 }
 164
 165 static int
 166 check_and_restore_fp_context(struct sigcontext __user *sc)
 167 {
 168         int err, sig;
 169
 170         err = sig = fpcsr_pending(&sc->sc_fpc_csr);
 171         if (err > 0)
 172                 err = 0;
 173         err |= protected_restore_fp_context(sc);
 174         return err ?: sig;
 175 }
 176
 177 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 178 {
 179         unsigned int used_math;
 180         unsigned long treg;
 181         int err = 0;
 182         int i;
 183
 184         /* Always make any pending restarted system calls return -EINTR */
 185         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 186
 187         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 188
 189 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 190         err |= __get_user(regs->acx, &sc->sc_acx);
 191 #endif
 192         err |= __get_user(regs->hi, &sc->sc_mdhi);
 193         err |= __get_user(regs->lo, &sc->sc_mdlo);
 194         if (cpu_has_dsp) {
 195                 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 196                 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 197                 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 198                 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 199                 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 200                 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 201                 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 202         }
 203
 204         for (i = 1; i < 32; i++)
 205                 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 206
 207         err |= __get_user(used_math, &sc->sc_used_math);
 208         conditional_used_math(used_math);
 209
 210         if (used_math) {
 211                 /* restore fpu context if we have used it before */
 212                 if (!err)
 213                         err = check_and_restore_fp_context(sc);
 214         } else {
 215                 /* signal handler may have used FPU.  Give it up. */
 216                 lose_fpu(0);
 217         }
 218
 219         return err;
 220 }
 221
 222 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 223                           size_t frame_size)
 224 {
 225         unsigned long sp;
 226
 227         /* Default to using normal stack */
 228         sp = regs->regs[29];
 229
 230         /*
 231          * FPU emulator may have it's own trampoline active just
 232          * above the user stack, 16-bytes before the next lowest
 233          * 16 byte boundary.  Try to avoid trashing it.
 234          */
 235         sp -= 32;
 236
 237         /* This is the X/Open sanctioned signal stack switching.  */
 238         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 239                 sp = current->sas_ss_sp + current->sas_ss_size;
 240
 241         return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
 242 }
 243
 244 /*
 245  * Atomically swap in the new signal mask, and wait for a signal.
 246  */
 247
 248 #ifdef CONFIG_TRAD_SIGNALS
 249 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
 250 {
 251         sigset_t newset;
 252         sigset_t __user *uset;
 253
 254         uset = (sigset_t __user *) regs.regs[4];
 255         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
 256                 return -EFAULT;
 257         sigdelsetmask(&newset, ~_BLOCKABLE);
 258
 259         spin_lock_irq(&current->sighand->siglock);
 260         current->saved_sigmask = current->blocked;
 261         current->blocked = newset;
 262         recalc_sigpending();
 263         spin_unlock_irq(&current->sighand->siglock);
 264
 265         current->state = TASK_INTERRUPTIBLE;
 266         schedule();
 267         set_thread_flag(TIF_RESTORE_SIGMASK);
 268         return -ERESTARTNOHAND;
 269 }
 270 #endif
 271
 272 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 273 {
 274         sigset_t newset;
 275         sigset_t __user *unewset;
 276         size_t sigsetsize;
 277
 278         /* XXX Don't preclude handling different sized sigset_t's.  */
 279         sigsetsize = regs.regs[5];
 280         if (sigsetsize != sizeof(sigset_t))
 281                 return -EINVAL;
 282
 283         unewset = (sigset_t __user *) regs.regs[4];
 284         if (copy_from_user(&newset, unewset, sizeof(newset)))
 285                 return -EFAULT;
 286         sigdelsetmask(&newset, ~_BLOCKABLE);
 287
 288         spin_lock_irq(&current->sighand->siglock);
 289         current->saved_sigmask = current->blocked;
 290         current->blocked = newset;
 291         recalc_sigpending();
 292         spin_unlock_irq(&current->sighand->siglock);
 293
 294         current->state = TASK_INTERRUPTIBLE;
 295         schedule();
 296         set_thread_flag(TIF_RESTORE_SIGMASK);
 297         return -ERESTARTNOHAND;
 298 }
 299
 300 #ifdef CONFIG_TRAD_SIGNALS
 301 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 302         struct sigaction __user *, oact)
 303 {
 304         struct k_sigaction new_ka, old_ka;
 305         int ret;
 306         int err = 0;
 307
 308         if (act) {
 309                 old_sigset_t mask;
 310
 311                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 312                         return -EFAULT;
 313                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 314                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 315                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 316                 if (err)
 317                         return -EFAULT;
 318
 319                 siginitset(&new_ka.sa.sa_mask, mask);
 320         }
 321
 322         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 323
 324         if (!ret && oact) {
 325                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 326                         return -EFAULT;
 327                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 328                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 329                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 330                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 331                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 332                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 333                 if (err)
 334                         return -EFAULT;
 335         }
 336
 337         return ret;
 338 }
 339 #endif
 340
 341 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 342 {
 343         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
 344         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
 345         unsigned long usp = regs.regs[29];
 346
 347         return do_sigaltstack(uss, uoss, usp);
 348 }
 349
 350 #ifdef CONFIG_TRAD_SIGNALS
 351 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 352 {
 353         struct sigframe __user *frame;
 354         sigset_t blocked;
 355         int sig;
 356
 357         frame = (struct sigframe __user *) regs.regs[29];
 358         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 359                 goto badframe;
 360         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 361                 goto badframe;
 362
 363         sigdelsetmask(&blocked, ~_BLOCKABLE);
 364         spin_lock_irq(&current->sighand->siglock);
 365         current->blocked = blocked;
 366         recalc_sigpending();
 367         spin_unlock_irq(&current->sighand->siglock);
 368
 369         sig = restore_sigcontext(&regs, &frame->sf_sc);
 370         if (sig < 0)
 371                 goto badframe;
 372         else if (sig)
 373                 force_sig(sig, current);
 374
 375         /*
 376          * Don't let your children do this ...
 377          */
 378         __asm__ __volatile__(
 379                 "move\t$29, %0\n\t"
 380                 "j\tsyscall_exit"
 381                 :/* no outputs */
 382                 :"r" (&regs));
 383         /* Unreached */
 384
 385 badframe:
 386         force_sig(SIGSEGV, current);
 387 }
 388 #endif /* CONFIG_TRAD_SIGNALS */
 389
 390 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 391 {
 392         struct rt_sigframe __user *frame;
 393         sigset_t set;
 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         /* It is more difficult to avoid calling this function than to
 415            call it and ignore errors.  */
 416         do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
 417
 418         /*
 419          * Don't let your children do this ...
 420          */
 421         __asm__ __volatile__(
 422                 "move\t$29, %0\n\t"
 423                 "j\tsyscall_exit"
 424                 :/* no outputs */
 425                 :"r" (&regs));
 426         /* Unreached */
 427
 428 badframe:
 429         force_sig(SIGSEGV, current);
 430 }
 431
 432 #ifdef CONFIG_TRAD_SIGNALS
 433 static int setup_frame(void *sig_return, struct k_sigaction *ka,
 434                        struct pt_regs *regs, int signr, sigset_t *set)
 435 {
 436         struct sigframe __user *frame;
 437         int err = 0;
 438
 439         frame = get_sigframe(ka, regs, sizeof(*frame));
 440         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 441                 goto give_sigsegv;
 442
 443         err |= setup_sigcontext(regs, &frame->sf_sc);
 444         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 445         if (err)
 446                 goto give_sigsegv;
 447
 448         /*
 449          * Arguments to signal handler:
 450          *
 451          *   a0 = signal number
 452          *   a1 = 0 (should be cause)
 453          *   a2 = pointer to struct sigcontext
 454          *
 455          * $25 and c0_epc point to the signal handler, $29 points to the
 456          * struct sigframe.
 457          */
 458         regs->regs[ 4] = signr;
 459         regs->regs[ 5] = 0;
 460         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 461         regs->regs[29] = (unsigned long) frame;
 462         regs->regs[31] = (unsigned long) sig_return;
 463         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 464
 465         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 466                current->comm, current->pid,
 467                frame, regs->cp0_epc, regs->regs[31]);
 468         return 0;
 469
 470 give_sigsegv:
 471         force_sigsegv(signr, current);
 472         return -EFAULT;
 473 }
 474 #endif
 475
 476 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
 477                           struct pt_regs *regs, int signr, sigset_t *set,
 478                           siginfo_t *info)
 479 {
 480         struct rt_sigframe __user *frame;
 481         int err = 0;
 482
 483         frame = get_sigframe(ka, regs, sizeof(*frame));
 484         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 485                 goto give_sigsegv;
 486
 487         /* Create siginfo.  */
 488         err |= copy_siginfo_to_user(&frame->rs_info, info);
 489
 490         /* Create the ucontext.  */
 491         err |= __put_user(0, &frame->rs_uc.uc_flags);
 492         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 493         err |= __put_user((void __user *)current->sas_ss_sp,
 494                           &frame->rs_uc.uc_stack.ss_sp);
 495         err |= __put_user(sas_ss_flags(regs->regs[29]),
 496                           &frame->rs_uc.uc_stack.ss_flags);
 497         err |= __put_user(current->sas_ss_size,
 498                           &frame->rs_uc.uc_stack.ss_size);
 499         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 500         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 501
 502         if (err)
 503                 goto give_sigsegv;
 504
 505         /*
 506          * Arguments to signal handler:
 507          *
 508          *   a0 = signal number
 509          *   a1 = 0 (should be cause)
 510          *   a2 = pointer to ucontext
 511          *
 512          * $25 and c0_epc point to the signal handler, $29 points to
 513          * the struct rt_sigframe.
 514          */
 515         regs->regs[ 4] = signr;
 516         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 517         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 518         regs->regs[29] = (unsigned long) frame;
 519         regs->regs[31] = (unsigned long) sig_return;
 520         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 521
 522         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 523                current->comm, current->pid,
 524                frame, regs->cp0_epc, regs->regs[31]);
 525
 526         return 0;
 527
 528 give_sigsegv:
 529         force_sigsegv(signr, current);
 530         return -EFAULT;
 531 }
 532
 533 struct mips_abi mips_abi = {
 534 #ifdef CONFIG_TRAD_SIGNALS
 535         .setup_frame    = setup_frame,
 536         .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
 537 #endif
 538         .setup_rt_frame = setup_rt_frame,
 539         .rt_signal_return_offset =
 540                 offsetof(struct mips_vdso, rt_signal_trampoline),
 541         .restart        = __NR_restart_syscall
 542 };
 543
 544 static int handle_signal(unsigned long sig, siginfo_t *info,
 545         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 546 {
 547         int ret;
 548         struct mips_abi *abi = current->thread.abi;
 549         void *vdso = current->mm->context.vdso;
 550
 551         if (regs->regs[0]) {
 552                 switch(regs->regs[2]) {
 553                 case ERESTART_RESTARTBLOCK:
 554                 case ERESTARTNOHAND:
 555                         regs->regs[2] = EINTR;
 556                         break;
 557                 case ERESTARTSYS:
 558                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 559                                 regs->regs[2] = EINTR;
 560                                 break;
 561                         }
 562                 /* fallthrough */
 563                 case ERESTARTNOINTR:
 564                         regs->regs[7] = regs->regs[26];
 565                         regs->regs[2] = regs->regs[0];
 566                         regs->cp0_epc -= 4;
 567                 }
 568
 569                 regs->regs[0] = 0;              /* Don't deal with this again.  */
 570         }
 571
 572         if (sig_uses_siginfo(ka))
 573                 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
 574                                           ka, regs, sig, oldset, info);
 575         else
 576                 ret = abi->setup_frame(vdso + abi->signal_return_offset,
 577                                        ka, regs, sig, oldset);
 578
 579         if (ret)
 580                 return ret;
 581
 582         spin_lock_irq(&current->sighand->siglock);
 583         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 584         if (!(ka->sa.sa_flags & SA_NODEFER))
 585                 sigaddset(&current->blocked, sig);
 586         recalc_sigpending();
 587         spin_unlock_irq(&current->sighand->siglock);
 588
 589         return ret;
 590 }
 591
 592 static void do_signal(struct pt_regs *regs)
 593 {
 594         struct k_sigaction ka;
 595         sigset_t *oldset;
 596         siginfo_t info;
 597         int signr;
 598
 599         /*
 600          * We want the common case to go fast, which is why we may in certain
 601          * cases get here from kernel mode. Just return without doing anything
 602          * if so.
 603          */
 604         if (!user_mode(regs))
 605                 return;
 606
 607         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 608                 oldset = &current->saved_sigmask;
 609         else
 610                 oldset = &current->blocked;
 611
 612         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 613         if (signr > 0) {
 614                 /* Whee!  Actually deliver the signal.  */
 615                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 616                         /*
 617                          * A signal was successfully delivered; the saved
 618                          * sigmask will have been stored in the signal frame,
 619                          * and will be restored by sigreturn, so we can simply
 620                          * clear the TIF_RESTORE_SIGMASK flag.
 621                          */
 622                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 623                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 624                 }
 625
 626                 return;
 627         }
 628
 629         if (regs->regs[0]) {
 630                 if (regs->regs[2] == ERESTARTNOHAND ||
 631                     regs->regs[2] == ERESTARTSYS ||
 632                     regs->regs[2] == ERESTARTNOINTR) {
 633                         regs->regs[2] = regs->regs[0];
 634                         regs->regs[7] = regs->regs[26];
 635                         regs->cp0_epc -= 4;
 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         local_irq_enable();
 663
 664         /* deal with pending signal delivery */
 665         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 666                 do_signal(regs);
 667
 668         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 669                 clear_thread_flag(TIF_NOTIFY_RESUME);
 670                 tracehook_notify_resume(regs);
 671                 if (current->replacement_session_keyring)
 672                         key_replace_session_keyring();
 673         }
 674 }
 675
 676 #ifdef CONFIG_SMP
 677 static int smp_save_fp_context(struct sigcontext __user *sc)
 678 {
 679         return raw_cpu_has_fpu
 680                ? _save_fp_context(sc)
 681                : fpu_emulator_save_context(sc);
 682 }
 683
 684 static int smp_restore_fp_context(struct sigcontext __user *sc)
 685 {
 686         return raw_cpu_has_fpu
 687                ? _restore_fp_context(sc)
 688                : fpu_emulator_restore_context(sc);
 689 }
 690 #endif
 691
 692 static int signal_setup(void)
 693 {
 694 #ifdef CONFIG_SMP
 695         /* For now just do the cpu_has_fpu check when the functions are invoked */
 696         save_fp_context = smp_save_fp_context;
 697         restore_fp_context = smp_restore_fp_context;
 698 #else
 699         if (cpu_has_fpu) {
 700                 save_fp_context = _save_fp_context;
 701                 restore_fp_context = _restore_fp_context;
 702         } else {
 703                 save_fp_context = fpu_emulator_save_context;
 704                 restore_fp_context = fpu_emulator_restore_context;
 705         }
 706 #endif
 707
 708         return 0;
 709 }
 710
 711 arch_initcall(signal_setup);