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        tbr = user->i.tbr;
 125        psr = user->i.psr;
 126        if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
 127                goto badframe;
 128        user->i.tbr = tbr;
 129        user->i.psr = psr;
 130
 131        restore_user_regs(user);
 132
 133        user->i.syscallno = -1;         /* disable syscall checks */
 134
 135        *_gr8 = user->i.gr[8];
 136        return 0;
 137
 138 badframe:
 139        return 1;
 140}
 141
 142asmlinkage int sys_sigreturn(void)
 143{
 144        struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
 145        sigset_t set;
 146        int gr8;
 147
 148        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 149                goto badframe;
 150        if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
 151                goto badframe;
 152
 153        if (_NSIG_WORDS > 1 &&
 154            __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
 155                goto badframe;
 156
 157        sigdelsetmask(&set, ~_BLOCKABLE);
 158        spin_lock_irq(&current->sighand->siglock);
 159        current->blocked = set;
 160        recalc_sigpending();
 161        spin_unlock_irq(&current->sighand->siglock);
 162
 163        if (restore_sigcontext(&frame->sc, &gr8))
 164                goto badframe;
 165        return gr8;
 166
 167 badframe:
 168        force_sig(SIGSEGV, current);
 169        return 0;
 170}
 171
 172asmlinkage int sys_rt_sigreturn(void)
 173{
 174        struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
 175        sigset_t set;
 176        int gr8;
 177
 178        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 179                goto badframe;
 180        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 181                goto badframe;
 182
 183        sigdelsetmask(&set, ~_BLOCKABLE);
 184        spin_lock_irq(&current->sighand->siglock);
 185        current->blocked = set;
 186        recalc_sigpending();
 187        spin_unlock_irq(&current->sighand->siglock);
 188
 189        if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
 190                goto badframe;
 191
 192        if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
 193                goto badframe;
 194
 195        return gr8;
 196
 197badframe:
 198        force_sig(SIGSEGV, current);
 199        return 0;
 200}
 201
 202/*
 203 * Set up a signal frame
 204 */
 205static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
 206{
 207        save_user_regs(current->thread.user);
 208
 209        if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
 210                goto badframe;
 211
 212        /* non-iBCS2 extensions.. */
 213        if (__put_user(mask, &sc->sc_oldmask) < 0)
 214                goto badframe;
 215
 216        return 0;
 217
 218 badframe:
 219        return 1;
 220}
 221
 222/*****************************************************************************/
 223/*
 224 * Determine which stack to use..
 225 */
 226static inline void __user *get_sigframe(struct k_sigaction *ka,
 227                                        size_t frame_size)
 228{
 229        unsigned long sp;
 230
 231        /* Default to using normal stack */
 232        sp = __frame->sp;
 233
 234        /* This is the X/Open sanctioned signal stack switching.  */
 235        if (ka->sa.sa_flags & SA_ONSTACK) {
 236                if (! sas_ss_flags(sp))
 237                        sp = current->sas_ss_sp + current->sas_ss_size;
 238        }
 239
 240        return (void __user *) ((sp - frame_size) & ~7UL);
 241
 242} /* end get_sigframe() */
 243
 244/*****************************************************************************/
 245/*
 246 *
 247 */
 248static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
 249{
 250        struct sigframe __user *frame;
 251        int rsig;
 252
 253        frame = get_sigframe(ka, sizeof(*frame));
 254
 255        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 256                goto give_sigsegv;
 257
 258        rsig = sig;
 259        if (sig < 32 &&
 260            __current_thread_info->exec_domain &&
 261            __current_thread_info->exec_domain->signal_invmap)
 262                rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 263
 264        if (__put_user(rsig, &frame->sig) < 0)
 265                goto give_sigsegv;
 266
 267        if (setup_sigcontext(&frame->sc, set->sig[0]))
 268                goto give_sigsegv;
 269
 270        if (_NSIG_WORDS > 1) {
 271                if (__copy_to_user(frame->extramask, &set->sig[1],
 272                                   sizeof(frame->extramask)))
 273                        goto give_sigsegv;
 274        }
 275
 276        /* Set up to return from userspace.  If provided, use a stub
 277         * already in userspace.  */
 278        if (ka->sa.sa_flags & SA_RESTORER) {
 279                if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
 280                        goto give_sigsegv;
 281        }
 282        else {
 283                /* Set up the following code on the stack:
 284                 *      setlos  #__NR_sigreturn,gr7
 285                 *      tira    gr0,0
 286                 */
 287                if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 288                    __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
 289                    __put_user(0xc0700000, &frame->retcode[1]))
 290                        goto give_sigsegv;
 291
 292                flush_icache_range((unsigned long) frame->retcode,
 293                                   (unsigned long) (frame->retcode + 2));
 294        }
 295
 296        /* set up registers for signal handler */
 297        __frame->sp   = (unsigned long) frame;
 298        __frame->lr   = (unsigned long) &frame->retcode;
 299        __frame->gr8  = sig;
 300
 301        if (current->personality & FDPIC_FUNCPTRS) {
 302                struct fdpic_func_descriptor __user *funcptr =
 303                        (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 304                __get_user(__frame->pc, &funcptr->text);
 305                __get_user(__frame->gr15, &funcptr->GOT);
 306        } else {
 307                __frame->pc   = (unsigned long) ka->sa.sa_handler;
 308                __frame->gr15 = 0;
 309        }
 310
 311        set_fs(USER_DS);
 312
 313        /* the tracer may want to single-step inside the handler */
 314        if (test_thread_flag(TIF_SINGLESTEP))
 315                ptrace_notify(SIGTRAP);
 316
 317#if DEBUG_SIG
 318        printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 319               sig, current->comm, current->pid, frame, __frame->pc,
 320               frame->pretcode);
 321#endif
 322
 323        return 0;
 324
 325give_sigsegv:
 326        force_sig(SIGSEGV, current);
 327        return -EFAULT;
 328
 329} /* end setup_frame() */
 330
 331/*****************************************************************************/
 332/*
 333 *
 334 */
 335static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 336                          sigset_t *set)
 337{
 338        struct rt_sigframe __user *frame;
 339        int rsig;
 340
 341        frame = get_sigframe(ka, sizeof(*frame));
 342
 343        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 344                goto give_sigsegv;
 345
 346        rsig = sig;
 347        if (sig < 32 &&
 348            __current_thread_info->exec_domain &&
 349            __current_thread_info->exec_domain->signal_invmap)
 350                rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 351
 352        if (__put_user(rsig,            &frame->sig) ||
 353            __put_user(&frame->info,    &frame->pinfo) ||
 354            __put_user(&frame->uc,      &frame->puc))
 355                goto give_sigsegv;
 356
 357        if (copy_siginfo_to_user(&frame->info, info))
 358                goto give_sigsegv;
 359
 360        /* Create the ucontext.  */
 361        if (__put_user(0, &frame->uc.uc_flags) ||
 362            __put_user(NULL, &frame->uc.uc_link) ||
 363            __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 364            __put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) ||
 365            __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
 366                goto give_sigsegv;
 367
 368        if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
 369                goto give_sigsegv;
 370
 371        if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 372                goto give_sigsegv;
 373
 374        /* Set up to return from userspace.  If provided, use a stub
 375         * already in userspace.  */
 376        if (ka->sa.sa_flags & SA_RESTORER) {
 377                if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 378                        goto give_sigsegv;
 379        }
 380        else {
 381                /* Set up the following code on the stack:
 382                 *      setlos  #__NR_sigreturn,gr7
 383                 *      tira    gr0,0
 384                 */
 385                if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 386                    __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
 387                    __put_user(0xc0700000, &frame->retcode[1]))
 388                        goto give_sigsegv;
 389
 390                flush_icache_range((unsigned long) frame->retcode,
 391                                   (unsigned long) (frame->retcode + 2));
 392        }
 393
 394        /* Set up registers for signal handler */
 395        __frame->sp  = (unsigned long) frame;
 396        __frame->lr   = (unsigned long) &frame->retcode;
 397        __frame->gr8 = sig;
 398        __frame->gr9 = (unsigned long) &frame->info;
 399
 400        if (current->personality & FDPIC_FUNCPTRS) {
 401                struct fdpic_func_descriptor __user *funcptr =
 402                        (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 403                __get_user(__frame->pc, &funcptr->text);
 404                __get_user(__frame->gr15, &funcptr->GOT);
 405        } else {
 406                __frame->pc   = (unsigned long) ka->sa.sa_handler;
 407                __frame->gr15 = 0;
 408        }
 409
 410        set_fs(USER_DS);
 411
 412        /* the tracer may want to single-step inside the handler */
 413        if (test_thread_flag(TIF_SINGLESTEP))
 414                ptrace_notify(SIGTRAP);
 415
 416#if DEBUG_SIG
 417        printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 418               sig, current->comm, current->pid, frame, __frame->pc,
 419               frame->pretcode);
 420#endif
 421
 422        return 0;
 423
 424give_sigsegv:
 425        force_sig(SIGSEGV, current);
 426        return -EFAULT;
 427
 428} /* end setup_rt_frame() */
 429
 430/*****************************************************************************/
 431/*
 432 * OK, we're invoking a handler
 433 */
 434static int handle_signal(unsigned long sig, siginfo_t *info,
 435                         struct k_sigaction *ka, sigset_t *oldset)
 436{
 437        int ret;
 438
 439        /* Are we from a system call? */
 440        if (in_syscall(__frame)) {
 441                /* If so, check system call restarting.. */
 442                switch (__frame->gr8) {
 443                case -ERESTART_RESTARTBLOCK:
 444                case -ERESTARTNOHAND:
 445                        __frame->gr8 = -EINTR;
 446                        break;
 447
 448                case -ERESTARTSYS:
 449                        if (!(ka->sa.sa_flags & SA_RESTART)) {
 450                                __frame->gr8 = -EINTR;
 451                                break;
 452                        }
 453
 454                        /* fallthrough */
 455                case -ERESTARTNOINTR:
 456                        __frame->gr8 = __frame->orig_gr8;
 457                        __frame->pc -= 4;
 458                }
 459        }
 460
 461        /* Set up the stack frame */
 462        if (ka->sa.sa_flags & SA_SIGINFO)
 463                ret = setup_rt_frame(sig, ka, info, oldset);
 464        else
 465                ret = setup_frame(sig, ka, oldset);
 466
 467        if (ret == 0) {
 468                spin_lock_irq(&current->sighand->siglock);
 469                sigorsets(&current->blocked, &current->blocked,
 470                          &ka->sa.sa_mask);
 471                if (!(ka->sa.sa_flags & SA_NODEFER))
 472                        sigaddset(&current->blocked, sig);
 473                recalc_sigpending();
 474                spin_unlock_irq(&current->sighand->siglock);
 475        }
 476
 477        return ret;
 478
 479} /* end handle_signal() */
 480
 481/*****************************************************************************/
 482/*
 483 * Note that 'init' is a special process: it doesn't get signals it doesn't
 484 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 485 * mistake.
 486 */
 487static void do_signal(void)
 488{
 489        struct k_sigaction ka;
 490        siginfo_t info;
 491        sigset_t *oldset;
 492        int signr;
 493
 494        /*
 495         * We want the common case to go fast, which
 496         * is why we may in certain cases get here from
 497         * kernel mode. Just return without doing anything
 498         * if so.
 499         */
 500        if (!user_mode(__frame))
 501                return;
 502
 503        if (try_to_freeze())
 504                goto no_signal;
 505
 506        if (test_thread_flag(TIF_RESTORE_SIGMASK))
 507                oldset = &current->saved_sigmask;
 508        else
 509                oldset = &current->blocked;
 510
 511        signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
 512        if (signr > 0) {
 513                if (handle_signal(signr, &info, &ka, oldset) == 0) {
 514                        /* a signal was successfully delivered; the saved
 515                         * sigmask will have been stored in the signal frame,
 516                         * and will be restored by sigreturn, so we can simply
 517                         * clear the TIF_RESTORE_SIGMASK flag */
 518                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
 519                                clear_thread_flag(TIF_RESTORE_SIGMASK);
 520
 521                        tracehook_signal_handler(signr, &info, &ka, __frame,
 522                                                 test_thread_flag(TIF_SINGLESTEP));
 523                }
 524
 525                return;
 526        }
 527
 528no_signal:
 529        /* Did we come from a system call? */
 530        if (__frame->syscallno != -1) {
 531                /* Restart the system call - no handlers present */
 532                switch (__frame->gr8) {
 533                case -ERESTARTNOHAND:
 534                case -ERESTARTSYS:
 535                case -ERESTARTNOINTR:
 536                        __frame->gr8 = __frame->orig_gr8;
 537                        __frame->pc -= 4;
 538                        break;
 539
 540                case -ERESTART_RESTARTBLOCK:
 541                        __frame->gr8 = __NR_restart_syscall;
 542                        __frame->pc -= 4;
 543                        break;
 544                }
 545        }
 546
 547        /* if there's no signal to deliver, we just put the saved sigmask
 548         * back */
 549        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 550                clear_thread_flag(TIF_RESTORE_SIGMASK);
 551                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 552        }
 553
 554} /* end do_signal() */
 555
 556/*****************************************************************************/
 557/*
 558 * notification of userspace execution resumption
 559 * - triggered by the TIF_WORK_MASK flags
 560 */
 561asmlinkage void do_notify_resume(__u32 thread_info_flags)
 562{
 563        /* pending single-step? */
 564        if (thread_info_flags & _TIF_SINGLESTEP)
 565                clear_thread_flag(TIF_SINGLESTEP);
 566
 567        /* deal with pending signal delivery */
 568        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 569                do_signal();
 570
 571        /* deal with notification on about to resume userspace execution */
 572        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 573                clear_thread_flag(TIF_NOTIFY_RESUME);
 574                tracehook_notify_resume(__frame);
 575                if (current->replacement_session_keyring)
 576                        key_replace_session_keyring();
 577        }
 578
 579} /* end do_notify_resume() */
 580