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
  36 #include "signal-common.h"
  37
  38 /*
  39  * Horribly complicated - with the bloody RM9000 workarounds enabled
  40  * the signal trampolines is moving to the end of the structure so we can
  41  * increase the alignment without breaking software compatibility.
  42  */
  43 #if ICACHE_REFILLS_WORKAROUND_WAR == 0
  44
  45 struct sigframe {
  46         u32 sf_ass[4];          /* argument save space for o32 */
  47         u32 sf_code[2];         /* signal trampoline */
  48         struct sigcontext sf_sc;
  49         sigset_t sf_mask;
  50 };
  51
  52 struct rt_sigframe {
  53         u32 rs_ass[4];          /* argument save space for o32 */
  54         u32 rs_code[2];         /* signal trampoline */
  55         struct siginfo rs_info;
  56         struct ucontext rs_uc;
  57 };
  58
  59 #else
  60
  61 struct sigframe {
  62         u32 sf_ass[4];                  /* argument save space for o32 */
  63         u32 sf_pad[2];
  64         struct sigcontext sf_sc;        /* hw context */
  65         sigset_t sf_mask;
  66         u32 sf_code[8] ____cacheline_aligned;   /* signal trampoline */
  67 };
  68
  69 struct rt_sigframe {
  70         u32 rs_ass[4];                  /* argument save space for o32 */
  71         u32 rs_pad[2];
  72         struct siginfo rs_info;
  73         struct ucontext rs_uc;
  74         u32 rs_code[8] ____cacheline_aligned;   /* signal trampoline */
  75 };
  76
  77 #endif
  78
  79 /*
  80  * Helper routines
  81  */
  82 static int protected_save_fp_context(struct sigcontext __user *sc)
  83 {
  84         int err;
  85         while (1) {
  86                 lock_fpu_owner();
  87                 own_fpu_inatomic(1);
  88                 err = save_fp_context(sc); /* this might fail */
  89                 unlock_fpu_owner();
  90                 if (likely(!err))
  91                         break;
  92                 /* touch the sigcontext and try again */
  93                 err = __put_user(0, &sc->sc_fpregs[0]) |
  94                         __put_user(0, &sc->sc_fpregs[31]) |
  95                         __put_user(0, &sc->sc_fpc_csr);
  96                 if (err)
  97                         break;  /* really bad sigcontext */
  98         }
  99         return err;
 100 }
 101
 102 static int protected_restore_fp_context(struct sigcontext __user *sc)
 103 {
 104         int err, tmp;
 105         while (1) {
 106                 lock_fpu_owner();
 107                 own_fpu_inatomic(0);
 108                 err = restore_fp_context(sc); /* this might fail */
 109                 unlock_fpu_owner();
 110                 if (likely(!err))
 111                         break;
 112                 /* touch the sigcontext and try again */
 113                 err = __get_user(tmp, &sc->sc_fpregs[0]) |
 114                         __get_user(tmp, &sc->sc_fpregs[31]) |
 115                         __get_user(tmp, &sc->sc_fpc_csr);
 116                 if (err)
 117                         break;  /* really bad sigcontext */
 118         }
 119         return err;
 120 }
 121
 122 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 123 {
 124         int err = 0;
 125         int i;
 126         unsigned int used_math;
 127
 128         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 129
 130         err |= __put_user(0, &sc->sc_regs[0]);
 131         for (i = 1; i < 32; i++)
 132                 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
 133
 134 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 135         err |= __put_user(regs->acx, &sc->sc_acx);
 136 #endif
 137         err |= __put_user(regs->hi, &sc->sc_mdhi);
 138         err |= __put_user(regs->lo, &sc->sc_mdlo);
 139         if (cpu_has_dsp) {
 140                 err |= __put_user(mfhi1(), &sc->sc_hi1);
 141                 err |= __put_user(mflo1(), &sc->sc_lo1);
 142                 err |= __put_user(mfhi2(), &sc->sc_hi2);
 143                 err |= __put_user(mflo2(), &sc->sc_lo2);
 144                 err |= __put_user(mfhi3(), &sc->sc_hi3);
 145                 err |= __put_user(mflo3(), &sc->sc_lo3);
 146                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 147         }
 148
 149         used_math = !!used_math();
 150         err |= __put_user(used_math, &sc->sc_used_math);
 151
 152         if (used_math) {
 153                 /*
 154                  * Save FPU state to signal context. Signal handler
 155                  * will "inherit" current FPU state.
 156                  */
 157                 err |= protected_save_fp_context(sc);
 158         }
 159         return err;
 160 }
 161
 162 int fpcsr_pending(unsigned int __user *fpcsr)
 163 {
 164         int err, sig = 0;
 165         unsigned int csr, enabled;
 166
 167         err = __get_user(csr, fpcsr);
 168         enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
 169         /*
 170          * If the signal handler set some FPU exceptions, clear it and
 171          * send SIGFPE.
 172          */
 173         if (csr & enabled) {
 174                 csr &= ~enabled;
 175                 err |= __put_user(csr, fpcsr);
 176                 sig = SIGFPE;
 177         }
 178         return err ?: sig;
 179 }
 180
 181 static int
 182 check_and_restore_fp_context(struct sigcontext __user *sc)
 183 {
 184         int err, sig;
 185
 186         err = sig = fpcsr_pending(&sc->sc_fpc_csr);
 187         if (err > 0)
 188                 err = 0;
 189         err |= protected_restore_fp_context(sc);
 190         return err ?: sig;
 191 }
 192
 193 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 194 {
 195         unsigned int used_math;
 196         unsigned long treg;
 197         int err = 0;
 198         int i;
 199
 200         /* Always make any pending restarted system calls return -EINTR */
 201         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 202
 203         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 204
 205 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 206         err |= __get_user(regs->acx, &sc->sc_acx);
 207 #endif
 208         err |= __get_user(regs->hi, &sc->sc_mdhi);
 209         err |= __get_user(regs->lo, &sc->sc_mdlo);
 210         if (cpu_has_dsp) {
 211                 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 212                 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 213                 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 214                 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 215                 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 216                 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 217                 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 218         }
 219
 220         for (i = 1; i < 32; i++)
 221                 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 222
 223         err |= __get_user(used_math, &sc->sc_used_math);
 224         conditional_used_math(used_math);
 225
 226         if (used_math) {
 227                 /* restore fpu context if we have used it before */
 228                 if (!err)
 229                         err = check_and_restore_fp_context(sc);
 230         } else {
 231                 /* signal handler may have used FPU.  Give it up. */
 232                 lose_fpu(0);
 233         }
 234
 235         return err;
 236 }
 237
 238 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 239                           size_t frame_size)
 240 {
 241         unsigned long sp;
 242
 243         /* Default to using normal stack */
 244         sp = regs->regs[29];
 245
 246         /*
 247          * FPU emulator may have it's own trampoline active just
 248          * above the user stack, 16-bytes before the next lowest
 249          * 16 byte boundary.  Try to avoid trashing it.
 250          */
 251         sp -= 32;
 252
 253         /* This is the X/Open sanctioned signal stack switching.  */
 254         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 255                 sp = current->sas_ss_sp + current->sas_ss_size;
 256
 257         return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
 258 }
 259
 260 int install_sigtramp(unsigned int __user *tramp, unsigned int syscall)
 261 {
 262         int err;
 263
 264         /*
 265          * Set up the return code ...
 266          *
 267          *         li      v0, __NR__foo_sigreturn
 268          *         syscall
 269          */
 270
 271         err = __put_user(0x24020000 + syscall, tramp + 0);
 272         err |= __put_user(0x0000000c         , tramp + 1);
 273         if (ICACHE_REFILLS_WORKAROUND_WAR) {
 274                 err |= __put_user(0, tramp + 2);
 275                 err |= __put_user(0, tramp + 3);
 276                 err |= __put_user(0, tramp + 4);
 277                 err |= __put_user(0, tramp + 5);
 278                 err |= __put_user(0, tramp + 6);
 279                 err |= __put_user(0, tramp + 7);
 280         }
 281         flush_cache_sigtramp((unsigned long) tramp);
 282
 283         return err;
 284 }
 285
 286 /*
 287  * Atomically swap in the new signal mask, and wait for a signal.
 288  */
 289
 290 #ifdef CONFIG_TRAD_SIGNALS
 291 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
 292 {
 293         sigset_t newset;
 294         sigset_t __user *uset;
 295
 296         uset = (sigset_t __user *) regs.regs[4];
 297         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
 298                 return -EFAULT;
 299         sigdelsetmask(&newset, ~_BLOCKABLE);
 300
 301         spin_lock_irq(&current->sighand->siglock);
 302         current->saved_sigmask = current->blocked;
 303         current->blocked = newset;
 304         recalc_sigpending();
 305         spin_unlock_irq(&current->sighand->siglock);
 306
 307         current->state = TASK_INTERRUPTIBLE;
 308         schedule();
 309         set_thread_flag(TIF_RESTORE_SIGMASK);
 310         return -ERESTARTNOHAND;
 311 }
 312 #endif
 313
 314 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 315 {
 316         sigset_t newset;
 317         sigset_t __user *unewset;
 318         size_t sigsetsize;
 319
 320         /* XXX Don't preclude handling different sized sigset_t's.  */
 321         sigsetsize = regs.regs[5];
 322         if (sigsetsize != sizeof(sigset_t))
 323                 return -EINVAL;
 324
 325         unewset = (sigset_t __user *) regs.regs[4];
 326         if (copy_from_user(&newset, unewset, sizeof(newset)))
 327                 return -EFAULT;
 328         sigdelsetmask(&newset, ~_BLOCKABLE);
 329
 330         spin_lock_irq(&current->sighand->siglock);
 331         current->saved_sigmask = current->blocked;
 332         current->blocked = newset;
 333         recalc_sigpending();
 334         spin_unlock_irq(&current->sighand->siglock);
 335
 336         current->state = TASK_INTERRUPTIBLE;
 337         schedule();
 338         set_thread_flag(TIF_RESTORE_SIGMASK);
 339         return -ERESTARTNOHAND;
 340 }
 341
 342 #ifdef CONFIG_TRAD_SIGNALS
 343 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 344         struct sigaction __user *, oact)
 345 {
 346         struct k_sigaction new_ka, old_ka;
 347         int ret;
 348         int err = 0;
 349
 350         if (act) {
 351                 old_sigset_t mask;
 352
 353                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 354                         return -EFAULT;
 355                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 356                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 357                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 358                 if (err)
 359                         return -EFAULT;
 360
 361                 siginitset(&new_ka.sa.sa_mask, mask);
 362         }
 363
 364         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 365
 366         if (!ret && oact) {
 367                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 368                         return -EFAULT;
 369                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 370                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 371                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 372                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 373                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 374                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 375                 if (err)
 376                         return -EFAULT;
 377         }
 378
 379         return ret;
 380 }
 381 #endif
 382
 383 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 384 {
 385         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
 386         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
 387         unsigned long usp = regs.regs[29];
 388
 389         return do_sigaltstack(uss, uoss, usp);
 390 }
 391
 392 #ifdef CONFIG_TRAD_SIGNALS
 393 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 394 {
 395         struct sigframe __user *frame;
 396         sigset_t blocked;
 397         int sig;
 398
 399         frame = (struct sigframe __user *) regs.regs[29];
 400         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 401                 goto badframe;
 402         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 403                 goto badframe;
 404
 405         sigdelsetmask(&blocked, ~_BLOCKABLE);
 406         spin_lock_irq(&current->sighand->siglock);
 407         current->blocked = blocked;
 408         recalc_sigpending();
 409         spin_unlock_irq(&current->sighand->siglock);
 410
 411         sig = restore_sigcontext(&regs, &frame->sf_sc);
 412         if (sig < 0)
 413                 goto badframe;
 414         else if (sig)
 415                 force_sig(sig, current);
 416
 417         /*
 418          * Don't let your children do this ...
 419          */
 420         __asm__ __volatile__(
 421                 "move\t$29, %0\n\t"
 422                 "j\tsyscall_exit"
 423                 :/* no outputs */
 424                 :"r" (&regs));
 425         /* Unreached */
 426
 427 badframe:
 428         force_sig(SIGSEGV, current);
 429 }
 430 #endif /* CONFIG_TRAD_SIGNALS */
 431
 432 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 433 {
 434         struct rt_sigframe __user *frame;
 435         sigset_t set;
 436         stack_t st;
 437         int sig;
 438
 439         frame = (struct rt_sigframe __user *) regs.regs[29];
 440         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 441                 goto badframe;
 442         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 443                 goto badframe;
 444
 445         sigdelsetmask(&set, ~_BLOCKABLE);
 446         spin_lock_irq(&current->sighand->siglock);
 447         current->blocked = set;
 448         recalc_sigpending();
 449         spin_unlock_irq(&current->sighand->siglock);
 450
 451         sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 452         if (sig < 0)
 453                 goto badframe;
 454         else if (sig)
 455                 force_sig(sig, current);
 456
 457         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 458                 goto badframe;
 459         /* It is more difficult to avoid calling this function than to
 460            call it and ignore errors.  */
 461         do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
 462
 463         /*
 464          * Don't let your children do this ...
 465          */
 466         __asm__ __volatile__(
 467                 "move\t$29, %0\n\t"
 468                 "j\tsyscall_exit"
 469                 :/* no outputs */
 470                 :"r" (&regs));
 471         /* Unreached */
 472
 473 badframe:
 474         force_sig(SIGSEGV, current);
 475 }
 476
 477 #ifdef CONFIG_TRAD_SIGNALS
 478 static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
 479         int signr, sigset_t *set)
 480 {
 481         struct sigframe __user *frame;
 482         int err = 0;
 483
 484         frame = get_sigframe(ka, regs, sizeof(*frame));
 485         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 486                 goto give_sigsegv;
 487
 488         err |= install_sigtramp(frame->sf_code, __NR_sigreturn);
 489
 490         err |= setup_sigcontext(regs, &frame->sf_sc);
 491         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 492         if (err)
 493                 goto give_sigsegv;
 494
 495         /*
 496          * Arguments to signal handler:
 497          *
 498          *   a0 = signal number
 499          *   a1 = 0 (should be cause)
 500          *   a2 = pointer to struct sigcontext
 501          *
 502          * $25 and c0_epc point to the signal handler, $29 points to the
 503          * struct sigframe.
 504          */
 505         regs->regs[ 4] = signr;
 506         regs->regs[ 5] = 0;
 507         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 508         regs->regs[29] = (unsigned long) frame;
 509         regs->regs[31] = (unsigned long) frame->sf_code;
 510         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 511
 512         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 513                current->comm, current->pid,
 514                frame, regs->cp0_epc, regs->regs[31]);
 515         return 0;
 516
 517 give_sigsegv:
 518         force_sigsegv(signr, current);
 519         return -EFAULT;
 520 }
 521 #endif
 522
 523 static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
 524         int signr, sigset_t *set, siginfo_t *info)
 525 {
 526         struct rt_sigframe __user *frame;
 527         int err = 0;
 528
 529         frame = get_sigframe(ka, regs, sizeof(*frame));
 530         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 531                 goto give_sigsegv;
 532
 533         err |= install_sigtramp(frame->rs_code, __NR_rt_sigreturn);
 534
 535         /* Create siginfo.  */
 536         err |= copy_siginfo_to_user(&frame->rs_info, info);
 537
 538         /* Create the ucontext.  */
 539         err |= __put_user(0, &frame->rs_uc.uc_flags);
 540         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 541         err |= __put_user((void __user *)current->sas_ss_sp,
 542                           &frame->rs_uc.uc_stack.ss_sp);
 543         err |= __put_user(sas_ss_flags(regs->regs[29]),
 544                           &frame->rs_uc.uc_stack.ss_flags);
 545         err |= __put_user(current->sas_ss_size,
 546                           &frame->rs_uc.uc_stack.ss_size);
 547         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 548         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 549
 550         if (err)
 551                 goto give_sigsegv;
 552
 553         /*
 554          * Arguments to signal handler:
 555          *
 556          *   a0 = signal number
 557          *   a1 = 0 (should be cause)
 558          *   a2 = pointer to ucontext
 559          *
 560          * $25 and c0_epc point to the signal handler, $29 points to
 561          * the struct rt_sigframe.
 562          */
 563         regs->regs[ 4] = signr;
 564         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 565         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 566         regs->regs[29] = (unsigned long) frame;
 567         regs->regs[31] = (unsigned long) frame->rs_code;
 568         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 569
 570         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 571                current->comm, current->pid,
 572                frame, regs->cp0_epc, regs->regs[31]);
 573
 574         return 0;
 575
 576 give_sigsegv:
 577         force_sigsegv(signr, current);
 578         return -EFAULT;
 579 }
 580
 581 struct mips_abi mips_abi = {
 582 #ifdef CONFIG_TRAD_SIGNALS
 583         .setup_frame    = setup_frame,
 584 #endif
 585         .setup_rt_frame = setup_rt_frame,
 586         .restart        = __NR_restart_syscall
 587 };
 588
 589 static int handle_signal(unsigned long sig, siginfo_t *info,
 590         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 591 {
 592         int ret;
 593
 594         switch(regs->regs[0]) {
 595         case ERESTART_RESTARTBLOCK:
 596         case ERESTARTNOHAND:
 597                 regs->regs[2] = EINTR;
 598                 break;
 599         case ERESTARTSYS:
 600                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 601                         regs->regs[2] = EINTR;
 602                         break;
 603                 }
 604         /* fallthrough */
 605         case ERESTARTNOINTR:            /* Userland will reload $v0.  */
 606                 regs->regs[7] = regs->regs[26];
 607                 regs->cp0_epc -= 8;
 608         }
 609
 610         regs->regs[0] = 0;              /* Don't deal with this again.  */
 611
 612         if (sig_uses_siginfo(ka))
 613                 ret = current->thread.abi->setup_rt_frame(ka, regs, sig, oldset, info);
 614         else
 615                 ret = current->thread.abi->setup_frame(ka, regs, sig, oldset);
 616
 617         spin_lock_irq(&current->sighand->siglock);
 618         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 619         if (!(ka->sa.sa_flags & SA_NODEFER))
 620                 sigaddset(&current->blocked, sig);
 621         recalc_sigpending();
 622         spin_unlock_irq(&current->sighand->siglock);
 623
 624         return ret;
 625 }
 626
 627 static void do_signal(struct pt_regs *regs)
 628 {
 629         struct k_sigaction ka;
 630         sigset_t *oldset;
 631         siginfo_t info;
 632         int signr;
 633
 634         /*
 635          * We want the common case to go fast, which is why we may in certain
 636          * cases get here from kernel mode. Just return without doing anything
 637          * if so.
 638          */
 639         if (!user_mode(regs))
 640                 return;
 641
 642         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 643                 oldset = &current->saved_sigmask;
 644         else
 645                 oldset = &current->blocked;
 646
 647         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 648         if (signr > 0) {
 649                 /* Whee!  Actually deliver the signal.  */
 650                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 651                         /*
 652                          * A signal was successfully delivered; the saved
 653                          * sigmask will have been stored in the signal frame,
 654                          * and will be restored by sigreturn, so we can simply
 655                          * clear the TIF_RESTORE_SIGMASK flag.
 656                          */
 657                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 658                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 659                 }
 660
 661                 return;
 662         }
 663
 664         /*
 665          * Who's code doesn't conform to the restartable syscall convention
 666          * dies here!!!  The li instruction, a single machine instruction,
 667          * must directly be followed by the syscall instruction.
 668          */
 669         if (regs->regs[0]) {
 670                 if (regs->regs[2] == ERESTARTNOHAND ||
 671                     regs->regs[2] == ERESTARTSYS ||
 672                     regs->regs[2] == ERESTARTNOINTR) {
 673                         regs->regs[7] = regs->regs[26];
 674                         regs->cp0_epc -= 8;
 675                 }
 676                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
 677                         regs->regs[2] = current->thread.abi->restart;
 678                         regs->regs[7] = regs->regs[26];
 679                         regs->cp0_epc -= 4;
 680                 }
 681                 regs->regs[0] = 0;      /* Don't deal with this again.  */
 682         }
 683
 684         /*
 685          * If there's no signal to deliver, we just put the saved sigmask
 686          * back
 687          */
 688         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 689                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 690                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 691         }
 692 }
 693
 694 /*
 695  * notification of userspace execution resumption
 696  * - triggered by the TIF_WORK_MASK flags
 697  */
 698 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 699         __u32 thread_info_flags)
 700 {
 701         /* deal with pending signal delivery */
 702         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 703                 do_signal(regs);
 704
 705         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 706                 clear_thread_flag(TIF_NOTIFY_RESUME);
 707                 tracehook_notify_resume(regs);
 708                 if (current->replacement_session_keyring)
 709                         key_replace_session_keyring();
 710         }
 711 }