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