release/src-rt-6.x.4708/linux/linux-2.6.36/arch/mn10300/kernel/signal.c

   1 /* MN10300 Signal handling
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11
  12 #include <linux/sched.h>
  13 #include <linux/mm.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/stddef.h>
  22 #include <linux/tty.h>
  23 #include <linux/personality.h>
  24 #include <linux/suspend.h>
  25 #include <linux/tracehook.h>
  26 #include <asm/cacheflush.h>
  27 #include <asm/ucontext.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/fpu.h>
  30 #include "sigframe.h"
  31
  32 #define DEBUG_SIG 0
  33
  34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  35
  36 /*
  37  * atomically swap in the new signal mask, and wait for a signal.
  38  */
  39 asmlinkage long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  40 {
  41         mask &= _BLOCKABLE;
  42         spin_lock_irq(&current->sighand->siglock);
  43         current->saved_sigmask = current->blocked;
  44         siginitset(&current->blocked, mask);
  45         recalc_sigpending();
  46         spin_unlock_irq(&current->sighand->siglock);
  47
  48         current->state = TASK_INTERRUPTIBLE;
  49         schedule();
  50         set_thread_flag(TIF_RESTORE_SIGMASK);
  51         return -ERESTARTNOHAND;
  52 }
  53
  54 /*
  55  * set signal action syscall
  56  */
  57 asmlinkage long sys_sigaction(int sig,
  58                               const struct old_sigaction __user *act,
  59                               struct old_sigaction __user *oact)
  60 {
  61         struct k_sigaction new_ka, old_ka;
  62         int ret;
  63
  64         if (act) {
  65                 old_sigset_t mask;
  66                 if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
  67                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  68                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
  69                     __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
  70                     __get_user(mask, &act->sa_mask))
  71                         return -EFAULT;
  72                 siginitset(&new_ka.sa.sa_mask, mask);
  73         }
  74
  75         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  76
  77         if (!ret && oact) {
  78                 if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
  79                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  80                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
  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                         return -EFAULT;
  84         }
  85
  86         return ret;
  87 }
  88
  89 /*
  90  * set alternate signal stack syscall
  91  */
  92 asmlinkage long sys_sigaltstack(const stack_t __user *uss, stack_t *uoss)
  93 {
  94         return do_sigaltstack(uss, uoss, __frame->sp);
  95 }
  96
  97 /*
  98  * do a signal return; undo the signal stack.
  99  */
 100 static int restore_sigcontext(struct pt_regs *regs,
 101                               struct sigcontext __user *sc, long *_d0)
 102 {
 103         unsigned int err = 0;
 104
 105         /* Always make any pending restarted system calls return -EINTR */
 106         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 107
 108         if (is_using_fpu(current))
 109                 fpu_kill_state(current);
 110
 111 #define COPY(x) err |= __get_user(regs->x, &sc->x)
 112         COPY(d1); COPY(d2); COPY(d3);
 113         COPY(a0); COPY(a1); COPY(a2); COPY(a3);
 114         COPY(e0); COPY(e1); COPY(e2); COPY(e3);
 115         COPY(e4); COPY(e5); COPY(e6); COPY(e7);
 116         COPY(lar); COPY(lir);
 117         COPY(mdr); COPY(mdrq);
 118         COPY(mcvf); COPY(mcrl); COPY(mcrh);
 119         COPY(sp); COPY(pc);
 120 #undef COPY
 121
 122         {
 123                 unsigned int tmpflags;
 124 #ifndef CONFIG_MN10300_USING_JTAG
 125 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
 126                    EPSW_T | EPSW_nAR)
 127 #else
 128 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
 129                    EPSW_nAR)
 130 #endif
 131                 err |= __get_user(tmpflags, &sc->epsw);
 132                 regs->epsw = (regs->epsw & ~USER_EPSW) |
 133                   (tmpflags & USER_EPSW);
 134                 regs->orig_d0 = -1;             /* disable syscall checks */
 135         }
 136
 137         {
 138                 struct fpucontext *buf;
 139                 err |= __get_user(buf, &sc->fpucontext);
 140                 if (buf) {
 141                         if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
 142                                 goto badframe;
 143                         err |= fpu_restore_sigcontext(buf);
 144                 }
 145         }
 146
 147         err |= __get_user(*_d0, &sc->d0);
 148         return err;
 149
 150 badframe:
 151         return 1;
 152 }
 153
 154 /*
 155  * standard signal return syscall
 156  */
 157 asmlinkage long sys_sigreturn(void)
 158 {
 159         struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
 160         sigset_t set;
 161         long d0;
 162
 163         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 164                 goto badframe;
 165         if (__get_user(set.sig[0], &frame->sc.oldmask))
 166                 goto badframe;
 167
 168         if (_NSIG_WORDS > 1 &&
 169             __copy_from_user(&set.sig[1], &frame->extramask,
 170                              sizeof(frame->extramask)))
 171                 goto badframe;
 172
 173         sigdelsetmask(&set, ~_BLOCKABLE);
 174         spin_lock_irq(&current->sighand->siglock);
 175         current->blocked = set;
 176         recalc_sigpending();
 177         spin_unlock_irq(&current->sighand->siglock);
 178
 179         if (restore_sigcontext(__frame, &frame->sc, &d0))
 180                 goto badframe;
 181
 182         return d0;
 183
 184 badframe:
 185         force_sig(SIGSEGV, current);
 186         return 0;
 187 }
 188
 189 /*
 190  * realtime signal return syscall
 191  */
 192 asmlinkage long sys_rt_sigreturn(void)
 193 {
 194         struct rt_sigframe __user *frame =
 195                 (struct rt_sigframe __user *) __frame->sp;
 196         sigset_t set;
 197         unsigned long d0;
 198
 199         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 200                 goto badframe;
 201         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 202                 goto badframe;
 203
 204         sigdelsetmask(&set, ~_BLOCKABLE);
 205         spin_lock_irq(&current->sighand->siglock);
 206         current->blocked = set;
 207         recalc_sigpending();
 208         spin_unlock_irq(&current->sighand->siglock);
 209
 210         if (restore_sigcontext(__frame, &frame->uc.uc_mcontext, &d0))
 211                 goto badframe;
 212
 213         if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
 214                 goto badframe;
 215
 216         return d0;
 217
 218 badframe:
 219         force_sig(SIGSEGV, current);
 220         return 0;
 221 }
 222
 223 /*
 224  * store the userspace context into a signal frame
 225  */
 226 static int setup_sigcontext(struct sigcontext __user *sc,
 227                             struct fpucontext *fpuctx,
 228                             struct pt_regs *regs,
 229                             unsigned long mask)
 230 {
 231         int tmp, err = 0;
 232
 233 #define COPY(x) err |= __put_user(regs->x, &sc->x)
 234         COPY(d0); COPY(d1); COPY(d2); COPY(d3);
 235         COPY(a0); COPY(a1); COPY(a2); COPY(a3);
 236         COPY(e0); COPY(e1); COPY(e2); COPY(e3);
 237         COPY(e4); COPY(e5); COPY(e6); COPY(e7);
 238         COPY(lar); COPY(lir);
 239         COPY(mdr); COPY(mdrq);
 240         COPY(mcvf); COPY(mcrl); COPY(mcrh);
 241         COPY(sp); COPY(epsw); COPY(pc);
 242 #undef COPY
 243
 244         tmp = fpu_setup_sigcontext(fpuctx);
 245         if (tmp < 0)
 246                 err = 1;
 247         else
 248                 err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);
 249
 250         /* non-iBCS2 extensions.. */
 251         err |= __put_user(mask, &sc->oldmask);
 252
 253         return err;
 254 }
 255
 256 /*
 257  * determine which stack to use..
 258  */
 259 static inline void __user *get_sigframe(struct k_sigaction *ka,
 260                                         struct pt_regs *regs,
 261                                         size_t frame_size)
 262 {
 263         unsigned long sp;
 264
 265         /* default to using normal stack */
 266         sp = regs->sp;
 267
 268         /* this is the X/Open sanctioned signal stack switching.  */
 269         if (ka->sa.sa_flags & SA_ONSTACK) {
 270                 if (sas_ss_flags(sp) == 0)
 271                         sp = current->sas_ss_sp + current->sas_ss_size;
 272         }
 273
 274         return (void __user *) ((sp - frame_size) & ~7UL);
 275 }
 276
 277 /*
 278  * set up a normal signal frame
 279  */
 280 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 281                        struct pt_regs *regs)
 282 {
 283         struct sigframe __user *frame;
 284         int rsig;
 285
 286         frame = get_sigframe(ka, regs, sizeof(*frame));
 287
 288         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 289                 goto give_sigsegv;
 290
 291         rsig = sig;
 292         if (sig < 32 &&
 293             current_thread_info()->exec_domain &&
 294             current_thread_info()->exec_domain->signal_invmap)
 295                 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
 296
 297         if (__put_user(rsig, &frame->sig) < 0 ||
 298             __put_user(&frame->sc, &frame->psc) < 0)
 299                 goto give_sigsegv;
 300
 301         if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
 302                 goto give_sigsegv;
 303
 304         if (_NSIG_WORDS > 1) {
 305                 if (__copy_to_user(frame->extramask, &set->sig[1],
 306                                    sizeof(frame->extramask)))
 307                         goto give_sigsegv;
 308         }
 309
 310         /* set up to return from userspace.  If provided, use a stub already in
 311          * userspace */
 312         if (ka->sa.sa_flags & SA_RESTORER) {
 313                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 314                         goto give_sigsegv;
 315         } else {
 316                 if (__put_user((void (*)(void))frame->retcode,
 317                                &frame->pretcode))
 318                         goto give_sigsegv;
 319                 /* this is mov $,d0; syscall 0 */
 320                 if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
 321                     __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
 322                     __put_user(0x00, (char *)(frame->retcode + 2)) ||
 323                     __put_user(0xf0, (char *)(frame->retcode + 3)) ||
 324                     __put_user(0xe0, (char *)(frame->retcode + 4)))
 325                         goto give_sigsegv;
 326                 flush_icache_range((unsigned long) frame->retcode,
 327                                    (unsigned long) frame->retcode + 5);
 328         }
 329
 330         /* set up registers for signal handler */
 331         regs->sp = (unsigned long) frame;
 332         regs->pc = (unsigned long) ka->sa.sa_handler;
 333         regs->d0 = sig;
 334         regs->d1 = (unsigned long) &frame->sc;
 335
 336         /* the tracer may want to single-step inside the handler */
 337         if (test_thread_flag(TIF_SINGLESTEP))
 338                 ptrace_notify(SIGTRAP);
 339
 340 #if DEBUG_SIG
 341         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 342                sig, current->comm, current->pid, frame, regs->pc,
 343                frame->pretcode);
 344 #endif
 345
 346         return 0;
 347
 348 give_sigsegv:
 349         force_sigsegv(sig, current);
 350         return -EFAULT;
 351 }
 352
 353 /*
 354  * set up a realtime signal frame
 355  */
 356 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 357                           sigset_t *set, struct pt_regs *regs)
 358 {
 359         struct rt_sigframe __user *frame;
 360         int rsig;
 361
 362         frame = get_sigframe(ka, regs, sizeof(*frame));
 363
 364         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 365                 goto give_sigsegv;
 366
 367         rsig = sig;
 368         if (sig < 32 &&
 369             current_thread_info()->exec_domain &&
 370             current_thread_info()->exec_domain->signal_invmap)
 371                 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
 372
 373         if (__put_user(rsig, &frame->sig) ||
 374             __put_user(&frame->info, &frame->pinfo) ||
 375             __put_user(&frame->uc, &frame->puc) ||
 376             copy_siginfo_to_user(&frame->info, info))
 377                 goto give_sigsegv;
 378
 379         /* create the ucontext.  */
 380         if (__put_user(0, &frame->uc.uc_flags) ||
 381             __put_user(0, &frame->uc.uc_link) ||
 382             __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 383             __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
 384             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size) ||
 385             setup_sigcontext(&frame->uc.uc_mcontext,
 386                              &frame->fpuctx, regs, set->sig[0]) ||
 387             __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 388                 goto give_sigsegv;
 389
 390         /* set up to return from userspace.  If provided, use a stub already in
 391          * userspace */
 392         if (ka->sa.sa_flags & SA_RESTORER) {
 393                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 394                         goto give_sigsegv;
 395         } else {
 396                 if (__put_user((void(*)(void))frame->retcode,
 397                                &frame->pretcode) ||
 398                     /* This is mov $,d0; syscall 0 */
 399                     __put_user(0x2c, (char *)(frame->retcode + 0)) ||
 400                     __put_user(__NR_rt_sigreturn,
 401                                (char *)(frame->retcode + 1)) ||
 402                     __put_user(0x00, (char *)(frame->retcode + 2)) ||
 403                     __put_user(0xf0, (char *)(frame->retcode + 3)) ||
 404                     __put_user(0xe0, (char *)(frame->retcode + 4)))
 405                         goto give_sigsegv;
 406
 407                 flush_icache_range((u_long) frame->retcode,
 408                                    (u_long) frame->retcode + 5);
 409         }
 410
 411         /* Set up registers for signal handler */
 412         regs->sp = (unsigned long) frame;
 413         regs->pc = (unsigned long) ka->sa.sa_handler;
 414         regs->d0 = sig;
 415         regs->d1 = (long) &frame->info;
 416
 417         /* the tracer may want to single-step inside the handler */
 418         if (test_thread_flag(TIF_SINGLESTEP))
 419                 ptrace_notify(SIGTRAP);
 420
 421 #if DEBUG_SIG
 422         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 423                sig, current->comm, current->pid, frame, regs->pc,
 424                frame->pretcode);
 425 #endif
 426
 427         return 0;
 428
 429 give_sigsegv:
 430         force_sigsegv(sig, current);
 431         return -EFAULT;
 432 }
 433
 434 static inline void stepback(struct pt_regs *regs)
 435 {
 436         regs->pc -= 2;
 437         regs->orig_d0 = -1;
 438 }
 439
 440 /*
 441  * handle the actual delivery of a signal to userspace
 442  */
 443 static int handle_signal(int sig,
 444                          siginfo_t *info, struct k_sigaction *ka,
 445                          sigset_t *oldset, struct pt_regs *regs)
 446 {
 447         int ret;
 448
 449         /* Are we from a system call? */
 450         if (regs->orig_d0 >= 0) {
 451                 /* If so, check system call restarting.. */
 452                 switch (regs->d0) {
 453                 case -ERESTART_RESTARTBLOCK:
 454                 case -ERESTARTNOHAND:
 455                         regs->d0 = -EINTR;
 456                         break;
 457
 458                 case -ERESTARTSYS:
 459                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 460                                 regs->d0 = -EINTR;
 461                                 break;
 462                         }
 463
 464                         /* fallthrough */
 465                 case -ERESTARTNOINTR:
 466                         regs->d0 = regs->orig_d0;
 467                         stepback(regs);
 468                 }
 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, regs);
 474         else
 475                 ret = setup_frame(sig, ka, oldset, regs);
 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
 490 /*
 491  * handle a potential signal
 492  */
 493 static void do_signal(struct pt_regs *regs)
 494 {
 495         struct k_sigaction ka;
 496         siginfo_t info;
 497         sigset_t *oldset;
 498         int signr;
 499
 500         /* we want the common case to go fast, which is why we may in certain
 501          * cases get here from kernel mode */
 502         if (!user_mode(regs))
 503                 return;
 504
 505         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 506                 oldset = &current->saved_sigmask;
 507         else
 508                 oldset = &current->blocked;
 509
 510         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 511         if (signr > 0) {
 512                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 513                         /* a signal was successfully delivered; the saved
 514                          * sigmask will have been stored in the signal frame,
 515                          * and will be restored by sigreturn, so we can simply
 516                          * clear the TIF_RESTORE_SIGMASK flag */
 517                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 518                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 519
 520                         tracehook_signal_handler(signr, &info, &ka, regs,
 521                                                  test_thread_flag(TIF_SINGLESTEP));
 522                 }
 523
 524                 return;
 525         }
 526
 527         /* did we come from a system call? */
 528         if (regs->orig_d0 >= 0) {
 529                 /* restart the system call - no handlers present */
 530                 switch (regs->d0) {
 531                 case -ERESTARTNOHAND:
 532                 case -ERESTARTSYS:
 533                 case -ERESTARTNOINTR:
 534                         regs->d0 = regs->orig_d0;
 535                         stepback(regs);
 536                         break;
 537
 538                 case -ERESTART_RESTARTBLOCK:
 539                         regs->d0 = __NR_restart_syscall;
 540                         stepback(regs);
 541                         break;
 542                 }
 543         }
 544
 545         /* if there's no signal to deliver, we just put the saved sigmask
 546          * back */
 547         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 548                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 549                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 550         }
 551 }
 552
 553 /*
 554  * notification of userspace execution resumption
 555  * - triggered by current->work.notify_resume
 556  */
 557 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 558 {
 559         /* Pending single-step? */
 560         if (thread_info_flags & _TIF_SINGLESTEP) {
 561 #ifndef CONFIG_MN10300_USING_JTAG
 562                 regs->epsw |= EPSW_T;
 563                 clear_thread_flag(TIF_SINGLESTEP);
 564 #else
 565                 BUG(); /* no h/w single-step if using JTAG unit */
 566 #endif
 567         }
 568
 569         /* deal with pending signal delivery */
 570         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 571                 do_signal(regs);
 572
 573         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 574                 clear_thread_flag(TIF_NOTIFY_RESUME);
 575                 tracehook_notify_resume(__frame);
 576                 if (current->replacement_session_keyring)
 577                         key_replace_session_keyring();
 578         }
 579 }