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/smp_lock.h>
  17 #include <linux/kernel.h>
  18 #include <linux/signal.h>
  19 #include <linux/errno.h>
  20 #include <linux/wait.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/unistd.h>
  23 #include <linux/personality.h>
  24 #include <linux/suspend.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
  33 struct fdpic_func_descriptor {
  34         unsigned long   text;
  35         unsigned long   GOT;
  36 };
  37
  38 asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
  39
  40 /*
  41  * Atomically swap in the new signal mask, and wait for a signal.
  42  */
  43 asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  44 {
  45         sigset_t saveset;
  46
  47         mask &= _BLOCKABLE;
  48         spin_lock_irq(&current->sighand->siglock);
  49         saveset = current->blocked;
  50         siginitset(&current->blocked, mask);
  51         recalc_sigpending();
  52         spin_unlock_irq(&current->sighand->siglock);
  53
  54         __frame->gr8 = -EINTR;
  55         while (1) {
  56                 current->state = TASK_INTERRUPTIBLE;
  57                 schedule();
  58                 if (do_signal(__frame, &saveset))
  59                         /* return the signal number as the return value of this function
  60                          * - this is an utterly evil hack. syscalls should not invoke do_signal()
  61                          *   as entry.S sets regs->gr8 to the return value of the system call
  62                          * - we can't just use sigpending() as we'd have to discard SIG_IGN signals
  63                          *   and call waitpid() if SIGCHLD needed discarding
  64                          * - this only works on the i386 because it passes arguments to the signal
  65                          *   handler on the stack, and the return value in EAX is effectively
  66                          *   discarded
  67                          */
  68                         return __frame->gr8;
  69         }
  70 }
  71
  72 asmlinkage int sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
  73 {
  74         sigset_t saveset, newset;
  75
  76         /* XXX: Don't preclude handling different sized sigset_t's.  */
  77         if (sigsetsize != sizeof(sigset_t))
  78                 return -EINVAL;
  79
  80         if (copy_from_user(&newset, unewset, sizeof(newset)))
  81                 return -EFAULT;
  82         sigdelsetmask(&newset, ~_BLOCKABLE);
  83
  84         spin_lock_irq(&current->sighand->siglock);
  85         saveset = current->blocked;
  86         current->blocked = newset;
  87         recalc_sigpending();
  88         spin_unlock_irq(&current->sighand->siglock);
  89
  90         __frame->gr8 = -EINTR;
  91         while (1) {
  92                 current->state = TASK_INTERRUPTIBLE;
  93                 schedule();
  94                 if (do_signal(__frame, &saveset))
  95                         /* return the signal number as the return value of this function
  96                          * - this is an utterly evil hack. syscalls should not invoke do_signal()
  97                          *   as entry.S sets regs->gr8 to the return value of the system call
  98                          * - we can't just use sigpending() as we'd have to discard SIG_IGN signals
  99                          *   and call waitpid() if SIGCHLD needed discarding
 100                          * - this only works on the i386 because it passes arguments to the signal
 101                          *   handler on the stack, and the return value in EAX is effectively
 102                          *   discarded
 103                          */
 104                         return __frame->gr8;
 105         }
 106 }
 107
 108 asmlinkage int sys_sigaction(int sig,
 109                              const struct old_sigaction __user *act,
 110                              struct old_sigaction __user *oact)
 111 {
 112         struct k_sigaction new_ka, old_ka;
 113         int ret;
 114
 115         if (act) {
 116                 old_sigset_t mask;
 117                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 118                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 119                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 120                         return -EFAULT;
 121                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 122                 __get_user(mask, &act->sa_mask);
 123                 siginitset(&new_ka.sa.sa_mask, mask);
 124         }
 125
 126         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 127
 128         if (!ret && oact) {
 129                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 130                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 131                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 132                         return -EFAULT;
 133                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 134                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 135         }
 136
 137         return ret;
 138 }
 139
 140 asmlinkage
 141 int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 142 {
 143         return do_sigaltstack(uss, uoss, __frame->sp);
 144 }
 145
 146
 147 /*
 148  * Do a signal return; undo the signal stack.
 149  */
 150
 151 struct sigframe
 152 {
 153         void (*pretcode)(void);
 154         int sig;
 155         struct sigcontext sc;
 156         unsigned long extramask[_NSIG_WORDS-1];
 157         uint32_t retcode[2];
 158 };
 159
 160 struct rt_sigframe
 161 {
 162         void (*pretcode)(void);
 163         int sig;
 164         struct siginfo *pinfo;
 165         void *puc;
 166         struct siginfo info;
 167         struct ucontext uc;
 168         uint32_t retcode[2];
 169 };
 170
 171 static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
 172 {
 173         struct user_context *user = current->thread.user;
 174         unsigned long tbr, psr;
 175
 176         tbr = user->i.tbr;
 177         psr = user->i.psr;
 178         if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
 179                 goto badframe;
 180         user->i.tbr = tbr;
 181         user->i.psr = psr;
 182
 183         restore_user_regs(user);
 184
 185         user->i.syscallno = -1;         /* disable syscall checks */
 186
 187         *_gr8 = user->i.gr[8];
 188         return 0;
 189
 190  badframe:
 191         return 1;
 192 }
 193
 194 asmlinkage int sys_sigreturn(void)
 195 {
 196         struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
 197         sigset_t set;
 198         int gr8;
 199
 200         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 201                 goto badframe;
 202         if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
 203                 goto badframe;
 204
 205         if (_NSIG_WORDS > 1 &&
 206             __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
 207                 goto badframe;
 208
 209         sigdelsetmask(&set, ~_BLOCKABLE);
 210         spin_lock_irq(&current->sighand->siglock);
 211         current->blocked = set;
 212         recalc_sigpending();
 213         spin_unlock_irq(&current->sighand->siglock);
 214
 215         if (restore_sigcontext(&frame->sc, &gr8))
 216                 goto badframe;
 217         return gr8;
 218
 219  badframe:
 220         force_sig(SIGSEGV, current);
 221         return 0;
 222 }
 223
 224 asmlinkage int sys_rt_sigreturn(void)
 225 {
 226         struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
 227         sigset_t set;
 228         int gr8;
 229
 230         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 231                 goto badframe;
 232         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 233                 goto badframe;
 234
 235         sigdelsetmask(&set, ~_BLOCKABLE);
 236         spin_lock_irq(&current->sighand->siglock);
 237         current->blocked = set;
 238         recalc_sigpending();
 239         spin_unlock_irq(&current->sighand->siglock);
 240
 241         if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
 242                 goto badframe;
 243
 244         if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
 245                 goto badframe;
 246
 247         return gr8;
 248
 249 badframe:
 250         force_sig(SIGSEGV, current);
 251         return 0;
 252 }
 253
 254 /*
 255  * Set up a signal frame
 256  */
 257 static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
 258 {
 259         save_user_regs(current->thread.user);
 260
 261         if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
 262                 goto badframe;
 263
 264         /* non-iBCS2 extensions.. */
 265         if (__put_user(mask, &sc->sc_oldmask) < 0)
 266                 goto badframe;
 267
 268         return 0;
 269
 270  badframe:
 271         return 1;
 272 }
 273
 274 /*****************************************************************************/
 275 /*
 276  * Determine which stack to use..
 277  */
 278 static inline void __user *get_sigframe(struct k_sigaction *ka,
 279                                         struct pt_regs *regs,
 280                                         size_t frame_size)
 281 {
 282         unsigned long sp;
 283
 284         /* Default to using normal stack */
 285         sp = regs->sp;
 286
 287         /* This is the X/Open sanctioned signal stack switching.  */
 288         if (ka->sa.sa_flags & SA_ONSTACK) {
 289                 if (! on_sig_stack(sp))
 290                         sp = current->sas_ss_sp + current->sas_ss_size;
 291         }
 292
 293         return (void __user *) ((sp - frame_size) & ~7UL);
 294 } /* end get_sigframe() */
 295
 296 /*****************************************************************************/
 297 /*
 298  *
 299  */
 300 static void setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs * regs)
 301 {
 302         struct sigframe __user *frame;
 303         int rsig;
 304
 305         frame = get_sigframe(ka, regs, sizeof(*frame));
 306
 307         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 308                 goto give_sigsegv;
 309
 310         rsig = sig;
 311         if (sig < 32 &&
 312             __current_thread_info->exec_domain &&
 313             __current_thread_info->exec_domain->signal_invmap)
 314                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 315
 316         if (__put_user(rsig, &frame->sig) < 0)
 317                 goto give_sigsegv;
 318
 319         if (setup_sigcontext(&frame->sc, set->sig[0]))
 320                 goto give_sigsegv;
 321
 322         if (_NSIG_WORDS > 1) {
 323                 if (__copy_to_user(frame->extramask, &set->sig[1],
 324                                    sizeof(frame->extramask)))
 325                         goto give_sigsegv;
 326         }
 327
 328         /* Set up to return from userspace.  If provided, use a stub
 329          * already in userspace.  */
 330         if (ka->sa.sa_flags & SA_RESTORER) {
 331                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
 332                         goto give_sigsegv;
 333         }
 334         else {
 335                 /* Set up the following code on the stack:
 336                  *      setlos  #__NR_sigreturn,gr7
 337                  *      tira    gr0,0
 338                  */
 339                 if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
 340                     __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
 341                     __put_user(0xc0700000, &frame->retcode[1]))
 342                         goto give_sigsegv;
 343
 344                 flush_icache_range((unsigned long) frame->retcode,
 345                                    (unsigned long) (frame->retcode + 2));
 346         }
 347
 348         /* set up registers for signal handler */
 349         regs->sp   = (unsigned long) frame;
 350         regs->lr   = (unsigned long) &frame->retcode;
 351         regs->gr8  = sig;
 352
 353         if (get_personality & FDPIC_FUNCPTRS) {
 354                 struct fdpic_func_descriptor __user *funcptr =
 355                         (struct fdpic_func_descriptor *) ka->sa.sa_handler;
 356                 __get_user(regs->pc, &funcptr->text);
 357                 __get_user(regs->gr15, &funcptr->GOT);
 358         } else {
 359                 regs->pc   = (unsigned long) ka->sa.sa_handler;
 360                 regs->gr15 = 0;
 361         }
 362
 363         set_fs(USER_DS);
 364
 365 #if DEBUG_SIG
 366         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 367                 sig, current->comm, current->pid, frame, regs->pc, frame->pretcode);
 368 #endif
 369
 370         return;
 371
 372 give_sigsegv:
 373         if (sig == SIGSEGV)
 374                 ka->sa.sa_handler = SIG_DFL;
 375
 376         force_sig(SIGSEGV, current);
 377 } /* end setup_frame() */
 378
 379 /*****************************************************************************/
 380 /*
 381  *
 382  */
 383 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 384                            sigset_t *set, struct pt_regs * regs)
 385 {
 386         struct rt_sigframe __user *frame;
 387         int rsig;
 388
 389         frame = get_sigframe(ka, regs, sizeof(*frame));
 390
 391         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 392                 goto give_sigsegv;
 393
 394         rsig = sig;
 395         if (sig < 32 &&
 396             __current_thread_info->exec_domain &&
 397             __current_thread_info->exec_domain->signal_invmap)
 398                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 399
 400         if (__put_user(rsig,            &frame->sig) ||
 401             __put_user(&frame->info,    &frame->pinfo) ||
 402             __put_user(&frame->uc,      &frame->puc))
 403                 goto give_sigsegv;
 404
 405         if (copy_siginfo_to_user(&frame->info, info))
 406                 goto give_sigsegv;
 407
 408         /* Create the ucontext.  */
 409         if (__put_user(0, &frame->uc.uc_flags) ||
 410             __put_user(0, &frame->uc.uc_link) ||
 411             __put_user((void*)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 412             __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
 413             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
 414                 goto give_sigsegv;
 415
 416         if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
 417                 goto give_sigsegv;
 418
 419         if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 420                 goto give_sigsegv;
 421
 422         /* Set up to return from userspace.  If provided, use a stub
 423          * already in userspace.  */
 424         if (ka->sa.sa_flags & SA_RESTORER) {
 425                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 426                         goto give_sigsegv;
 427         }
 428         else {
 429                 /* Set up the following code on the stack:
 430                  *      setlos  #__NR_sigreturn,gr7
 431                  *      tira    gr0,0
 432                  */
 433                 if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
 434                     __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
 435                     __put_user(0xc0700000, &frame->retcode[1]))
 436                         goto give_sigsegv;
 437
 438                 flush_icache_range((unsigned long) frame->retcode,
 439                                    (unsigned long) (frame->retcode + 2));
 440         }
 441
 442         /* Set up registers for signal handler */
 443         regs->sp  = (unsigned long) frame;
 444         regs->lr   = (unsigned long) &frame->retcode;
 445         regs->gr8 = sig;
 446         regs->gr9 = (unsigned long) &frame->info;
 447
 448         if (get_personality & FDPIC_FUNCPTRS) {
 449                 struct fdpic_func_descriptor *funcptr =
 450                         (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 451                 __get_user(regs->pc, &funcptr->text);
 452                 __get_user(regs->gr15, &funcptr->GOT);
 453         } else {
 454                 regs->pc   = (unsigned long) ka->sa.sa_handler;
 455                 regs->gr15 = 0;
 456         }
 457
 458         set_fs(USER_DS);
 459
 460 #if DEBUG_SIG
 461         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 462                 sig, current->comm, current->pid, frame, regs->pc, frame->pretcode);
 463 #endif
 464
 465         return;
 466
 467 give_sigsegv:
 468         if (sig == SIGSEGV)
 469                 ka->sa.sa_handler = SIG_DFL;
 470         force_sig(SIGSEGV, current);
 471
 472 } /* end setup_rt_frame() */
 473
 474 /*****************************************************************************/
 475 /*
 476  * OK, we're invoking a handler
 477  */
 478 static void handle_signal(unsigned long sig, siginfo_t *info,
 479                           struct k_sigaction *ka, sigset_t *oldset,
 480                           struct pt_regs *regs)
 481 {
 482         /* Are we from a system call? */
 483         if (in_syscall(regs)) {
 484                 /* If so, check system call restarting.. */
 485                 switch (regs->gr8) {
 486                 case -ERESTART_RESTARTBLOCK:
 487                 case -ERESTARTNOHAND:
 488                         regs->gr8 = -EINTR;
 489                         break;
 490
 491                 case -ERESTARTSYS:
 492                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 493                                 regs->gr8 = -EINTR;
 494                                 break;
 495                         }
 496                         /* fallthrough */
 497                 case -ERESTARTNOINTR:
 498                         regs->gr8 = regs->orig_gr8;
 499                         regs->pc -= 4;
 500                 }
 501         }
 502
 503         /* Set up the stack frame */
 504         if (ka->sa.sa_flags & SA_SIGINFO)
 505                 setup_rt_frame(sig, ka, info, oldset, regs);
 506         else
 507                 setup_frame(sig, ka, oldset, regs);
 508
 509         if (!(ka->sa.sa_flags & SA_NODEFER)) {
 510                 spin_lock_irq(&current->sighand->siglock);
 511                 sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 512                 sigaddset(&current->blocked, sig);
 513                 recalc_sigpending();
 514                 spin_unlock_irq(&current->sighand->siglock);
 515         }
 516 } /* end handle_signal() */
 517
 518 /*****************************************************************************/
 519 /*
 520  * Note that 'init' is a special process: it doesn't get signals it doesn't
 521  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 522  * mistake.
 523  */
 524 int do_signal(struct pt_regs *regs, sigset_t *oldset)
 525 {
 526         struct k_sigaction ka;
 527         siginfo_t info;
 528         int signr;
 529
 530         /*
 531          * We want the common case to go fast, which
 532          * is why we may in certain cases get here from
 533          * kernel mode. Just return without doing anything
 534          * if so.
 535          */
 536         if (!user_mode(regs))
 537                 return 1;
 538
 539         if (try_to_freeze())
 540                 goto no_signal;
 541
 542         if (!oldset)
 543                 oldset = &current->blocked;
 544
 545         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 546         if (signr > 0) {
 547                 handle_signal(signr, &info, &ka, oldset, regs);
 548                 return 1;
 549         }
 550
 551  no_signal:
 552         /* Did we come from a system call? */
 553         if (regs->syscallno >= 0) {
 554                 /* Restart the system call - no handlers present */
 555                 if (regs->gr8 == -ERESTARTNOHAND ||
 556                     regs->gr8 == -ERESTARTSYS ||
 557                     regs->gr8 == -ERESTARTNOINTR) {
 558                         regs->gr8 = regs->orig_gr8;
 559                         regs->pc -= 4;
 560                 }
 561
 562                 if (regs->gr8 == -ERESTART_RESTARTBLOCK){
 563                         regs->gr8 = __NR_restart_syscall;
 564                         regs->pc -= 4;
 565                 }
 566         }
 567
 568         return 0;
 569 } /* end do_signal() */
 570
 571 /*****************************************************************************/
 572 /*
 573  * notification of userspace execution resumption
 574  * - triggered by current->work.notify_resume
 575  */
 576 asmlinkage void do_notify_resume(__u32 thread_info_flags)
 577 {
 578         /* pending single-step? */
 579         if (thread_info_flags & _TIF_SINGLESTEP)
 580                 clear_thread_flag(TIF_SINGLESTEP);
 581
 582         /* deal with pending signal delivery */
 583         if (thread_info_flags & _TIF_SIGPENDING)
 584                 do_signal(__frame, NULL);
 585
 586 } /* end do_notify_resume() */