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         return sigsuspend(&newset);
 259 }
 260 #endif
 261
 262 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 263 {
 264         sigset_t newset;
 265         sigset_t __user *unewset;
 266         size_t sigsetsize;
 267
 268         /* XXX Don't preclude handling different sized sigset_t's.  */
 269         sigsetsize = regs.regs[5];
 270         if (sigsetsize != sizeof(sigset_t))
 271                 return -EINVAL;
 272
 273         unewset = (sigset_t __user *) regs.regs[4];
 274         if (copy_from_user(&newset, unewset, sizeof(newset)))
 275                 return -EFAULT;
 276         return sigsuspend(&newset);
 277 }
 278
 279 #ifdef CONFIG_TRAD_SIGNALS
 280 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 281         struct sigaction __user *, oact)
 282 {
 283         struct k_sigaction new_ka, old_ka;
 284         int ret;
 285         int err = 0;
 286
 287         if (act) {
 288                 old_sigset_t mask;
 289
 290                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 291                         return -EFAULT;
 292                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 293                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 294                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 295                 if (err)
 296                         return -EFAULT;
 297
 298                 siginitset(&new_ka.sa.sa_mask, mask);
 299         }
 300
 301         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 302
 303         if (!ret && oact) {
 304                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 305                         return -EFAULT;
 306                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 307                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 308                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 309                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 310                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 311                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 312                 if (err)
 313                         return -EFAULT;
 314         }
 315
 316         return ret;
 317 }
 318 #endif
 319
 320 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 321 {
 322         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
 323         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
 324         unsigned long usp = regs.regs[29];
 325
 326         return do_sigaltstack(uss, uoss, usp);
 327 }
 328
 329 #ifdef CONFIG_TRAD_SIGNALS
 330 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 331 {
 332         struct sigframe __user *frame;
 333         sigset_t blocked;
 334         int sig;
 335
 336         frame = (struct sigframe __user *) regs.regs[29];
 337         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 338                 goto badframe;
 339         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 340                 goto badframe;
 341
 342         sigdelsetmask(&blocked, ~_BLOCKABLE);
 343         set_current_blocked(&blocked);
 344
 345         sig = restore_sigcontext(&regs, &frame->sf_sc);
 346         if (sig < 0)
 347                 goto badframe;
 348         else if (sig)
 349                 force_sig(sig, current);
 350
 351         /*
 352          * Don't let your children do this ...
 353          */
 354         __asm__ __volatile__(
 355                 "move\t$29, %0\n\t"
 356                 "j\tsyscall_exit"
 357                 :/* no outputs */
 358                 :"r" (&regs));
 359         /* Unreached */
 360
 361 badframe:
 362         force_sig(SIGSEGV, current);
 363 }
 364 #endif /* CONFIG_TRAD_SIGNALS */
 365
 366 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 367 {
 368         struct rt_sigframe __user *frame;
 369         sigset_t set;
 370         int sig;
 371
 372         frame = (struct rt_sigframe __user *) regs.regs[29];
 373         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 374                 goto badframe;
 375         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 376                 goto badframe;
 377
 378         sigdelsetmask(&set, ~_BLOCKABLE);
 379         set_current_blocked(&set);
 380
 381         sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 382         if (sig < 0)
 383                 goto badframe;
 384         else if (sig)
 385                 force_sig(sig, current);
 386
 387         /* It is more difficult to avoid calling this function than to
 388            call it and ignore errors.  */
 389         do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]);
 390
 391         /*
 392          * Don't let your children do this ...
 393          */
 394         __asm__ __volatile__(
 395                 "move\t$29, %0\n\t"
 396                 "j\tsyscall_exit"
 397                 :/* no outputs */
 398                 :"r" (&regs));
 399         /* Unreached */
 400
 401 badframe:
 402         force_sig(SIGSEGV, current);
 403 }
 404
 405 #ifdef CONFIG_TRAD_SIGNALS
 406 static int setup_frame(void *sig_return, struct k_sigaction *ka,
 407                        struct pt_regs *regs, int signr, sigset_t *set)
 408 {
 409         struct sigframe __user *frame;
 410         int err = 0;
 411
 412         frame = get_sigframe(ka, regs, sizeof(*frame));
 413         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 414                 goto give_sigsegv;
 415
 416         err |= setup_sigcontext(regs, &frame->sf_sc);
 417         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 418         if (err)
 419                 goto give_sigsegv;
 420
 421         /*
 422          * Arguments to signal handler:
 423          *
 424          *   a0 = signal number
 425          *   a1 = 0 (should be cause)
 426          *   a2 = pointer to struct sigcontext
 427          *
 428          * $25 and c0_epc point to the signal handler, $29 points to the
 429          * struct sigframe.
 430          */
 431         regs->regs[ 4] = signr;
 432         regs->regs[ 5] = 0;
 433         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 434         regs->regs[29] = (unsigned long) frame;
 435         regs->regs[31] = (unsigned long) sig_return;
 436         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 437
 438         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 439                current->comm, current->pid,
 440                frame, regs->cp0_epc, regs->regs[31]);
 441         return 0;
 442
 443 give_sigsegv:
 444         force_sigsegv(signr, current);
 445         return -EFAULT;
 446 }
 447 #endif
 448
 449 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
 450                           struct pt_regs *regs, int signr, sigset_t *set,
 451                           siginfo_t *info)
 452 {
 453         struct rt_sigframe __user *frame;
 454         int err = 0;
 455
 456         frame = get_sigframe(ka, regs, sizeof(*frame));
 457         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 458                 goto give_sigsegv;
 459
 460         /* Create siginfo.  */
 461         err |= copy_siginfo_to_user(&frame->rs_info, info);
 462
 463         /* Create the ucontext.  */
 464         err |= __put_user(0, &frame->rs_uc.uc_flags);
 465         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 466         err |= __put_user((void __user *)current->sas_ss_sp,
 467                           &frame->rs_uc.uc_stack.ss_sp);
 468         err |= __put_user(sas_ss_flags(regs->regs[29]),
 469                           &frame->rs_uc.uc_stack.ss_flags);
 470         err |= __put_user(current->sas_ss_size,
 471                           &frame->rs_uc.uc_stack.ss_size);
 472         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 473         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 474
 475         if (err)
 476                 goto give_sigsegv;
 477
 478         /*
 479          * Arguments to signal handler:
 480          *
 481          *   a0 = signal number
 482          *   a1 = 0 (should be cause)
 483          *   a2 = pointer to ucontext
 484          *
 485          * $25 and c0_epc point to the signal handler, $29 points to
 486          * the struct rt_sigframe.
 487          */
 488         regs->regs[ 4] = signr;
 489         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 490         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 491         regs->regs[29] = (unsigned long) frame;
 492         regs->regs[31] = (unsigned long) sig_return;
 493         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 494
 495         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 496                current->comm, current->pid,
 497                frame, regs->cp0_epc, regs->regs[31]);
 498
 499         return 0;
 500
 501 give_sigsegv:
 502         force_sigsegv(signr, current);
 503         return -EFAULT;
 504 }
 505
 506 struct mips_abi mips_abi = {
 507 #ifdef CONFIG_TRAD_SIGNALS
 508         .setup_frame    = setup_frame,
 509         .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
 510 #endif
 511         .setup_rt_frame = setup_rt_frame,
 512         .rt_signal_return_offset =
 513                 offsetof(struct mips_vdso, rt_signal_trampoline),
 514         .restart        = __NR_restart_syscall
 515 };
 516
 517 static int handle_signal(unsigned long sig, siginfo_t *info,
 518         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 519 {
 520         int ret;
 521         struct mips_abi *abi = current->thread.abi;
 522         void *vdso = current->mm->context.vdso;
 523
 524         if (regs->regs[0]) {
 525                 switch(regs->regs[2]) {
 526                 case ERESTART_RESTARTBLOCK:
 527                 case ERESTARTNOHAND:
 528                         regs->regs[2] = EINTR;
 529                         break;
 530                 case ERESTARTSYS:
 531                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 532                                 regs->regs[2] = EINTR;
 533                                 break;
 534                         }
 535                 /* fallthrough */
 536                 case ERESTARTNOINTR:
 537                         regs->regs[7] = regs->regs[26];
 538                         regs->regs[2] = regs->regs[0];
 539                         regs->cp0_epc -= 4;
 540                 }
 541
 542                 regs->regs[0] = 0;              /* Don't deal with this again.  */
 543         }
 544
 545         if (sig_uses_siginfo(ka))
 546                 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
 547                                           ka, regs, sig, oldset, info);
 548         else
 549                 ret = abi->setup_frame(vdso + abi->signal_return_offset,
 550                                        ka, regs, sig, oldset);
 551
 552         if (ret)
 553                 return ret;
 554
 555         block_sigmask(ka, sig);
 556
 557         return ret;
 558 }
 559
 560 static void do_signal(struct pt_regs *regs)
 561 {
 562         struct k_sigaction ka;
 563         sigset_t *oldset;
 564         siginfo_t info;
 565         int signr;
 566
 567         /*
 568          * We want the common case to go fast, which is why we may in certain
 569          * cases get here from kernel mode. Just return without doing anything
 570          * if so.
 571          */
 572         if (!user_mode(regs))
 573                 return;
 574
 575         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 576                 oldset = &current->saved_sigmask;
 577         else
 578                 oldset = &current->blocked;
 579
 580         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 581         if (signr > 0) {
 582                 /* Whee!  Actually deliver the signal.  */
 583                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 584                         /*
 585                          * A signal was successfully delivered; the saved
 586                          * sigmask will have been stored in the signal frame,
 587                          * and will be restored by sigreturn, so we can simply
 588                          * clear the TIF_RESTORE_SIGMASK flag.
 589                          */
 590                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 591                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 592                 }
 593
 594                 return;
 595         }
 596
 597         if (regs->regs[0]) {
 598                 if (regs->regs[2] == ERESTARTNOHAND ||
 599                     regs->regs[2] == ERESTARTSYS ||
 600                     regs->regs[2] == ERESTARTNOINTR) {
 601                         regs->regs[2] = regs->regs[0];
 602                         regs->regs[7] = regs->regs[26];
 603                         regs->cp0_epc -= 4;
 604                 }
 605                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
 606                         regs->regs[2] = current->thread.abi->restart;
 607                         regs->regs[7] = regs->regs[26];
 608                         regs->cp0_epc -= 4;
 609                 }
 610                 regs->regs[0] = 0;      /* Don't deal with this again.  */
 611         }
 612
 613         /*
 614          * If there's no signal to deliver, we just put the saved sigmask
 615          * back
 616          */
 617         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 618                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 619                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 620         }
 621 }
 622
 623 /*
 624  * notification of userspace execution resumption
 625  * - triggered by the TIF_WORK_MASK flags
 626  */
 627 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 628         __u32 thread_info_flags)
 629 {
 630         local_irq_enable();
 631
 632         /* deal with pending signal delivery */
 633         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 634                 do_signal(regs);
 635
 636         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 637                 clear_thread_flag(TIF_NOTIFY_RESUME);
 638                 tracehook_notify_resume(regs);
 639                 if (current->replacement_session_keyring)
 640                         key_replace_session_keyring();
 641         }
 642 }
 643
 644 #ifdef CONFIG_SMP
 645 static int smp_save_fp_context(struct sigcontext __user *sc)
 646 {
 647         return raw_cpu_has_fpu
 648                ? _save_fp_context(sc)
 649                : fpu_emulator_save_context(sc);
 650 }
 651
 652 static int smp_restore_fp_context(struct sigcontext __user *sc)
 653 {
 654         return raw_cpu_has_fpu
 655                ? _restore_fp_context(sc)
 656                : fpu_emulator_restore_context(sc);
 657 }
 658 #endif
 659
 660 static int signal_setup(void)
 661 {
 662 #ifdef CONFIG_SMP
 663         /* For now just do the cpu_has_fpu check when the functions are invoked */
 664         save_fp_context = smp_save_fp_context;
 665         restore_fp_context = smp_restore_fp_context;
 666 #else
 667         if (cpu_has_fpu) {
 668                 save_fp_context = _save_fp_context;
 669                 restore_fp_context = _restore_fp_context;
 670         } else {
 671                 save_fp_context = fpu_emulator_save_context;
 672                 restore_fp_context = fpu_emulator_restore_context;
 673         }
 674 #endif
 675
 676         return 0;
 677 }
 678
 679 arch_initcall(signal_setup);