LXR linux/arch/frv/kernel/signal.c

   1/* signal.c: FRV specific bits of signal handling
   2 *
   3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 * - Derived from arch/m68k/kernel/signal.c
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * as published by the Free Software Foundation; either version
  10 * 2 of the License, or (at your option) any later version.
  11 */
  12
  13#include <linux/sched.h>
  14#include <linux/mm.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/personality.h>
  23#include <linux/freezer.h>
  24#include <linux/tracehook.h>
  25#include <asm/ucontext.h>
  26#include <asm/uaccess.h>
  27#include <asm/cacheflush.h>
  28
  29#define DEBUG_SIG 0
  30
  31#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  32
  33struct fdpic_func_descriptor {
  34        unsigned long   text;
  35        unsigned long   GOT;
  36};
  37
  38/*
  39 * Atomically swap in the new signal mask, and wait for a signal.
  40 */
  41asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  42{
  43        mask &= _BLOCKABLE;
  44        spin_lock_irq(&current->sighand->siglock);
  45        current->saved_sigmask = current->blocked;
  46        siginitset(&current->blocked, mask);
  47        recalc_sigpending();
  48        spin_unlock_irq(&current->sighand->siglock);
  49
  50        current->state = TASK_INTERRUPTIBLE;
  51        schedule();
  52        set_thread_flag(TIF_RESTORE_SIGMASK);
  53        return -ERESTARTNOHAND;
  54}
  55
  56asmlinkage int sys_sigaction(int sig,
  57                             const struct old_sigaction __user *act,
  58                             struct old_sigaction __user *oact)
  59{
  60        struct k_sigaction new_ka, old_ka;
  61        int ret;
  62
  63        if (act) {
  64                old_sigset_t mask;
  65                if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  66                    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  67                    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  68                        return -EFAULT;
  69                __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  70                __get_user(mask, &act->sa_mask);
  71                siginitset(&new_ka.sa.sa_mask, mask);
  72        }
  73
  74        ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  75
  76        if (!ret && oact) {
  77                if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  78                    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  79                    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  80                        return -EFAULT;
  81                __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  82                __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  83        }
  84
  85        return ret;
  86}
  87
  88asmlinkage
  89int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
  90{
  91        return do_sigaltstack(uss, uoss, __frame->sp);
  92}
  93
  94
  95/*
  96 * Do a signal return; undo the signal stack.
  97 */
  98
  99struct sigframe
 100{
 101        __sigrestore_t pretcode;
 102        int sig;
 103        struct sigcontext sc;
 104        unsigned long extramask[_NSIG_WORDS-1];
 105        uint32_t retcode[2];
 106};
 107
 108struct rt_sigframe
 109{
 110        __sigrestore_t pretcode;
 111        int sig;
 112        struct siginfo __user *pinfo;
 113        void __user *puc;
 114        struct siginfo info;
 115        struct ucontext uc;
 116        uint32_t retcode[2];
 117};
 118
 119static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
 120{
 121        struct user_context *user = current->thread.user;
 122        unsigned long tbr, psr;
 123
 124        /* Always make any pending restarted system calls return -EINTR */
 125        current_thread_info()->restart_block.fn = do_no_restart_syscall;
 126
 127        tbr = user->i.tbr;
 128        psr = user->i.psr;
 129        if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
 130                goto badframe;
 131        user->i.tbr = tbr;
 132        user->i.psr = psr;
 133
 134        restore_user_regs(user);
 135
 136        user->i.syscallno = -1;         /* disable syscall checks */
 137
 138        *_gr8 = user->i.gr[8];
 139        return 0;
 140
 141 badframe:
 142        return 1;
 143}
 144
 145asmlinkage int sys_sigreturn(void)
 146{
 147        struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
 148        sigset_t set;
 149        int gr8;
 150
 151        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 152                goto badframe;
 153        if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
 154                goto badframe;
 155
 156        if (_NSIG_WORDS > 1 &&
 157            __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
 158                goto badframe;
 159
 160        sigdelsetmask(&set, ~_BLOCKABLE);
 161        spin_lock_irq(&current->sighand->siglock);
 162        current->blocked = set;
 163        recalc_sigpending();
 164        spin_unlock_irq(&current->sighand->siglock);
 165
 166        if (restore_sigcontext(&frame->sc, &gr8))
 167                goto badframe;
 168        return gr8;
 169
 170 badframe:
 171        force_sig(SIGSEGV, current);
 172        return 0;
 173}
 174
 175asmlinkage int sys_rt_sigreturn(void)
 176{
 177        struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
 178        sigset_t set;
 179        int gr8;
 180
 181        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 182                goto badframe;
 183        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 184                goto badframe;
 185
 186        sigdelsetmask(&set, ~_BLOCKABLE);
 187        spin_lock_irq(&current->sighand->siglock);
 188        current->blocked = set;
 189        recalc_sigpending();
 190        spin_unlock_irq(&current->sighand->siglock);
 191
 192        if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
 193                goto badframe;
 194
 195        if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
 196                goto badframe;
 197
 198        return gr8;
 199
 200badframe:
 201        force_sig(SIGSEGV, current);
 202        return 0;
 203}
 204
 205/*
 206 * Set up a signal frame
 207 */
 208static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
 209{
 210        save_user_regs(current->thread.user);
 211
 212        if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
 213                goto badframe;
 214
 215        /* non-iBCS2 extensions.. */
 216        if (__put_user(mask, &sc->sc_oldmask) < 0)
 217                goto badframe;
 218
 219        return 0;
 220
 221 badframe:
 222        return 1;
 223}
 224
 225/*****************************************************************************/
 226/*
 227 * Determine which stack to use..
 228 */
 229static inline void __user *get_sigframe(struct k_sigaction *ka,
 230                                        size_t frame_size)
 231{
 232        unsigned long sp;
 233
 234        /* Default to using normal stack */
 235        sp = __frame->sp;
 236
 237        /* This is the X/Open sanctioned signal stack switching.  */
 238        if (ka->sa.sa_flags & SA_ONSTACK) {
 239                if (! sas_ss_flags(sp))
 240                        sp = current->sas_ss_sp + current->sas_ss_size;
 241        }
 242
 243        return (void __user *) ((sp - frame_size) & ~7UL);
 244
 245} /* end get_sigframe() */
 246
 247/*****************************************************************************/
 248/*
 249 *
 250 */
 251static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
 252{
 253        struct sigframe __user *frame;
 254        int rsig;
 255
 256        set_fs(USER_DS);
 257
 258        frame = get_sigframe(ka, sizeof(*frame));
 259
 260        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 261                goto give_sigsegv;
 262
 263        rsig = sig;
 264        if (sig < 32 &&
 265            __current_thread_info->exec_domain &&
 266            __current_thread_info->exec_domain->signal_invmap)
 267                rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 268
 269        if (__put_user(rsig, &frame->sig) < 0)
 270                goto give_sigsegv;
 271
 272        if (setup_sigcontext(&frame->sc, set->sig[0]))
 273                goto give_sigsegv;
 274
 275        if (_NSIG_WORDS > 1) {
 276                if (__copy_to_user(frame->extramask, &set->sig[1],
 277                                   sizeof(frame->extramask)))
 278                        goto give_sigsegv;
 279        }
 280
 281        /* Set up to return from userspace.  If provided, use a stub
 282         * already in userspace.  */
 283        if (ka->sa.sa_flags & SA_RESTORER) {
 284                if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
 285                        goto give_sigsegv;
 286        }
 287        else {
 288                /* Set up the following code on the stack:
 289                 *      setlos  #__NR_sigreturn,gr7
 290                 *      tira    gr0,0
 291                 */
 292                if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 293                    __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
 294                    __put_user(0xc0700000, &frame->retcode[1]))
 295                        goto give_sigsegv;
 296
 297                flush_icache_range((unsigned long) frame->retcode,
 298                                   (unsigned long) (frame->retcode + 2));
 299        }
 300
 301        /* Set up registers for the signal handler */
 302        if (current->personality & FDPIC_FUNCPTRS) {
 303                struct fdpic_func_descriptor __user *funcptr =
 304                        (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 305                struct fdpic_func_descriptor desc;
 306                if (copy_from_user(&desc, funcptr, sizeof(desc)))
 307                        goto give_sigsegv;
 308                __frame->pc = desc.text;
 309                __frame->gr15 = desc.GOT;
 310        } else {
 311                __frame->pc   = (unsigned long) ka->sa.sa_handler;
 312                __frame->gr15 = 0;
 313        }
 314
 315        __frame->sp   = (unsigned long) frame;
 316        __frame->lr   = (unsigned long) &frame->retcode;
 317        __frame->gr8  = sig;
 318
 319        /* the tracer may want to single-step inside the handler */
 320        if (test_thread_flag(TIF_SINGLESTEP))
 321                ptrace_notify(SIGTRAP);
 322
 323#if DEBUG_SIG
 324        printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 325               sig, current->comm, current->pid, frame, __frame->pc,
 326               frame->pretcode);
 327#endif
 328
 329        return 0;
 330
 331give_sigsegv:
 332        force_sigsegv(sig, current);
 333        return -EFAULT;
 334
 335} /* end setup_frame() */
 336
 337/*****************************************************************************/
 338/*
 339 *
 340 */
 341static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 342                          sigset_t *set)
 343{
 344        struct rt_sigframe __user *frame;
 345        int rsig;
 346
 347        set_fs(USER_DS);
 348
 349        frame = get_sigframe(ka, sizeof(*frame));
 350
 351        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 352                goto give_sigsegv;
 353
 354        rsig = sig;
 355        if (sig < 32 &&
 356            __current_thread_info->exec_domain &&
 357            __current_thread_info->exec_domain->signal_invmap)
 358                rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 359
 360        if (__put_user(rsig,            &frame->sig) ||
 361            __put_user(&frame->info,    &frame->pinfo) ||
 362            __put_user(&frame->uc,      &frame->puc))
 363                goto give_sigsegv;
 364
 365        if (copy_siginfo_to_user(&frame->info, info))
 366                goto give_sigsegv;
 367
 368        /* Create the ucontext.  */
 369        if (__put_user(0, &frame->uc.uc_flags) ||
 370            __put_user(NULL, &frame->uc.uc_link) ||
 371            __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 372            __put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) ||
 373            __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
 374                goto give_sigsegv;
 375
 376        if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
 377                goto give_sigsegv;
 378
 379        if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 380                goto give_sigsegv;
 381
 382        /* Set up to return from userspace.  If provided, use a stub
 383         * already in userspace.  */
 384        if (ka->sa.sa_flags & SA_RESTORER) {
 385                if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 386                        goto give_sigsegv;
 387        }
 388        else {
 389                /* Set up the following code on the stack:
 390                 *      setlos  #__NR_sigreturn,gr7
 391                 *      tira    gr0,0
 392                 */
 393                if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 394                    __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
 395                    __put_user(0xc0700000, &frame->retcode[1]))
 396                        goto give_sigsegv;
 397
 398                flush_icache_range((unsigned long) frame->retcode,
 399                                   (unsigned long) (frame->retcode + 2));
 400        }
 401
 402        /* Set up registers for signal handler */
 403        if (current->personality & FDPIC_FUNCPTRS) {
 404                struct fdpic_func_descriptor __user *funcptr =
 405                        (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 406                struct fdpic_func_descriptor desc;
 407                if (copy_from_user(&desc, funcptr, sizeof(desc)))
 408                        goto give_sigsegv;
 409                __frame->pc = desc.text;
 410                __frame->gr15 = desc.GOT;
 411        } else {
 412                __frame->pc   = (unsigned long) ka->sa.sa_handler;
 413                __frame->gr15 = 0;
 414        }
 415
 416        __frame->sp  = (unsigned long) frame;
 417        __frame->lr  = (unsigned long) &frame->retcode;
 418        __frame->gr8 = sig;
 419        __frame->gr9 = (unsigned long) &frame->info;
 420
 421        /* the tracer may want to single-step inside the handler */
 422        if (test_thread_flag(TIF_SINGLESTEP))
 423                ptrace_notify(SIGTRAP);
 424
 425#if DEBUG_SIG
 426        printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 427               sig, current->comm, current->pid, frame, __frame->pc,
 428               frame->pretcode);
 429#endif
 430
 431        return 0;
 432
 433give_sigsegv:
 434        force_sigsegv(sig, current);
 435        return -EFAULT;
 436
 437} /* end setup_rt_frame() */
 438
 439/*****************************************************************************/
 440/*
 441 * OK, we're invoking a handler
 442 */
 443static int handle_signal(unsigned long sig, siginfo_t *info,
 444                         struct k_sigaction *ka, sigset_t *oldset)
 445{
 446        int ret;
 447
 448        /* Are we from a system call? */
 449        if (__frame->syscallno != -1) {
 450                /* If so, check system call restarting.. */
 451                switch (__frame->gr8) {
 452                case -ERESTART_RESTARTBLOCK:
 453                case -ERESTARTNOHAND:
 454                        __frame->gr8 = -EINTR;
 455                        break;
 456
 457                case -ERESTARTSYS:
 458                        if (!(ka->sa.sa_flags & SA_RESTART)) {
 459                                __frame->gr8 = -EINTR;
 460                                break;
 461                        }
 462
 463                        /* fallthrough */
 464                case -ERESTARTNOINTR:
 465                        __frame->gr8 = __frame->orig_gr8;
 466                        __frame->pc -= 4;
 467                }
 468                __frame->syscallno = -1;
 469        }
 470
 471        /* Set up the stack frame */
 472        if (ka->sa.sa_flags & SA_SIGINFO)
 473                ret = setup_rt_frame(sig, ka, info, oldset);
 474        else
 475                ret = setup_frame(sig, ka, oldset);
 476
 477        if (ret == 0) {
 478                spin_lock_irq(&current->sighand->siglock);
 479                sigorsets(&current->blocked, &current->blocked,
 480                          &ka->sa.sa_mask);
 481                if (!(ka->sa.sa_flags & SA_NODEFER))
 482                        sigaddset(&current->blocked, sig);
 483                recalc_sigpending();
 484                spin_unlock_irq(&current->sighand->siglock);
 485        }
 486
 487        return ret;
 488
 489} /* end handle_signal() */
 490
 491/*****************************************************************************/
 492/*
 493 * Note that 'init' is a special process: it doesn't get signals it doesn't
 494 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 495 * mistake.
 496 */
 497static void do_signal(void)
 498{
 499        struct k_sigaction ka;
 500        siginfo_t info;
 501        sigset_t *oldset;
 502        int signr;
 503
 504        /*
 505         * We want the common case to go fast, which
 506         * is why we may in certain cases get here from
 507         * kernel mode. Just return without doing anything
 508         * if so.
 509         */
 510        if (!user_mode(__frame))
 511                return;
 512
 513        if (try_to_freeze())
 514                goto no_signal;
 515
 516        if (test_thread_flag(TIF_RESTORE_SIGMASK))
 517                oldset = &current->saved_sigmask;
 518        else
 519                oldset = &current->blocked;
 520
 521        signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
 522        if (signr > 0) {
 523                if (handle_signal(signr, &info, &ka, oldset) == 0) {
 524                        /* a signal was successfully delivered; the saved
 525                         * sigmask will have been stored in the signal frame,
 526                         * and will be restored by sigreturn, so we can simply
 527                         * clear the TIF_RESTORE_SIGMASK flag */
 528                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
 529                                clear_thread_flag(TIF_RESTORE_SIGMASK);
 530
 531                        tracehook_signal_handler(signr, &info, &ka, __frame,
 532                                                 test_thread_flag(TIF_SINGLESTEP));
 533                }
 534
 535                return;
 536        }
 537
 538no_signal:
 539        /* Did we come from a system call? */
 540        if (__frame->syscallno != -1) {
 541                /* Restart the system call - no handlers present */
 542                switch (__frame->gr8) {
 543                case -ERESTARTNOHAND:
 544                case -ERESTARTSYS:
 545                case -ERESTARTNOINTR:
 546                        __frame->gr8 = __frame->orig_gr8;
 547                        __frame->pc -= 4;
 548                        break;
 549
 550                case -ERESTART_RESTARTBLOCK:
 551                        __frame->gr7 = __NR_restart_syscall;
 552                        __frame->pc -= 4;
 553                        break;
 554                }
 555                __frame->syscallno = -1;
 556        }
 557
 558        /* if there's no signal to deliver, we just put the saved sigmask
 559         * back */
 560        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 561                clear_thread_flag(TIF_RESTORE_SIGMASK);
 562                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 563        }
 564
 565} /* end do_signal() */
 566
 567/*****************************************************************************/
 568/*
 569 * notification of userspace execution resumption
 570 * - triggered by the TIF_WORK_MASK flags
 571 */
 572asmlinkage void do_notify_resume(__u32 thread_info_flags)
 573{
 574        /* pending single-step? */
 575        if (thread_info_flags & _TIF_SINGLESTEP)
 576                clear_thread_flag(TIF_SINGLESTEP);
 577
 578        /* deal with pending signal delivery */
 579        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 580                do_signal();
 581
 582        /* deal with notification on about to resume userspace execution */
 583        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 584                clear_thread_flag(TIF_NOTIFY_RESUME);
 585                tracehook_notify_resume(__frame);
 586                if (current->replacement_session_keyring)
 587                        key_replace_session_keyring();
 588        }
 589
 590} /* end do_notify_resume() */
 591