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 int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 301                        struct pt_regs *regs)
 302 {
 303         struct sigframe __user *frame;
 304         int rsig;
 305
 306         frame = get_sigframe(ka, regs, sizeof(*frame));
 307
 308         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 309                 goto give_sigsegv;
 310
 311         rsig = sig;
 312         if (sig < 32 &&
 313             __current_thread_info->exec_domain &&
 314             __current_thread_info->exec_domain->signal_invmap)
 315                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 316
 317         if (__put_user(rsig, &frame->sig) < 0)
 318                 goto give_sigsegv;
 319
 320         if (setup_sigcontext(&frame->sc, set->sig[0]))
 321                 goto give_sigsegv;
 322
 323         if (_NSIG_WORDS > 1) {
 324                 if (__copy_to_user(frame->extramask, &set->sig[1],
 325                                    sizeof(frame->extramask)))
 326                         goto give_sigsegv;
 327         }
 328
 329         /* Set up to return from userspace.  If provided, use a stub
 330          * already in userspace.  */
 331         if (ka->sa.sa_flags & SA_RESTORER) {
 332                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
 333                         goto give_sigsegv;
 334         }
 335         else {
 336                 /* Set up the following code on the stack:
 337                  *      setlos  #__NR_sigreturn,gr7
 338                  *      tira    gr0,0
 339                  */
 340                 if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
 341                     __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
 342                     __put_user(0xc0700000, &frame->retcode[1]))
 343                         goto give_sigsegv;
 344
 345                 flush_icache_range((unsigned long) frame->retcode,
 346                                    (unsigned long) (frame->retcode + 2));
 347         }
 348
 349         /* set up registers for signal handler */
 350         regs->sp   = (unsigned long) frame;
 351         regs->lr   = (unsigned long) &frame->retcode;
 352         regs->gr8  = sig;
 353
 354         if (get_personality & FDPIC_FUNCPTRS) {
 355                 struct fdpic_func_descriptor __user *funcptr =
 356                         (struct fdpic_func_descriptor *) ka->sa.sa_handler;
 357                 __get_user(regs->pc, &funcptr->text);
 358                 __get_user(regs->gr15, &funcptr->GOT);
 359         } else {
 360                 regs->pc   = (unsigned long) ka->sa.sa_handler;
 361                 regs->gr15 = 0;
 362         }
 363
 364         set_fs(USER_DS);
 365
 366         /* the tracer may want to single-step inside the handler */
 367         if (test_thread_flag(TIF_SINGLESTEP))
 368                 ptrace_notify(SIGTRAP);
 369
 370 #if DEBUG_SIG
 371         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 372                sig, current->comm, current->pid, frame, regs->pc,
 373                frame->pretcode);
 374 #endif
 375
 376         return 1;
 377
 378 give_sigsegv:
 379         force_sig(SIGSEGV, current);
 380         return 0;
 381
 382 } /* end setup_frame() */
 383
 384 /*****************************************************************************/
 385 /*
 386  *
 387  */
 388 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 389                           sigset_t *set, struct pt_regs * regs)
 390 {
 391         struct rt_sigframe __user *frame;
 392         int rsig;
 393
 394         frame = get_sigframe(ka, regs, sizeof(*frame));
 395
 396         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 397                 goto give_sigsegv;
 398
 399         rsig = sig;
 400         if (sig < 32 &&
 401             __current_thread_info->exec_domain &&
 402             __current_thread_info->exec_domain->signal_invmap)
 403                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 404
 405         if (__put_user(rsig,            &frame->sig) ||
 406             __put_user(&frame->info,    &frame->pinfo) ||
 407             __put_user(&frame->uc,      &frame->puc))
 408                 goto give_sigsegv;
 409
 410         if (copy_siginfo_to_user(&frame->info, info))
 411                 goto give_sigsegv;
 412
 413         /* Create the ucontext.  */
 414         if (__put_user(0, &frame->uc.uc_flags) ||
 415             __put_user(0, &frame->uc.uc_link) ||
 416             __put_user((void*)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 417             __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
 418             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
 419                 goto give_sigsegv;
 420
 421         if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
 422                 goto give_sigsegv;
 423
 424         if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 425                 goto give_sigsegv;
 426
 427         /* Set up to return from userspace.  If provided, use a stub
 428          * already in userspace.  */
 429         if (ka->sa.sa_flags & SA_RESTORER) {
 430                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 431                         goto give_sigsegv;
 432         }
 433         else {
 434                 /* Set up the following code on the stack:
 435                  *      setlos  #__NR_sigreturn,gr7
 436                  *      tira    gr0,0
 437                  */
 438                 if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
 439                     __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
 440                     __put_user(0xc0700000, &frame->retcode[1]))
 441                         goto give_sigsegv;
 442
 443                 flush_icache_range((unsigned long) frame->retcode,
 444                                    (unsigned long) (frame->retcode + 2));
 445         }
 446
 447         /* Set up registers for signal handler */
 448         regs->sp  = (unsigned long) frame;
 449         regs->lr   = (unsigned long) &frame->retcode;
 450         regs->gr8 = sig;
 451         regs->gr9 = (unsigned long) &frame->info;
 452
 453         if (get_personality & FDPIC_FUNCPTRS) {
 454                 struct fdpic_func_descriptor *funcptr =
 455                         (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 456                 __get_user(regs->pc, &funcptr->text);
 457                 __get_user(regs->gr15, &funcptr->GOT);
 458         } else {
 459                 regs->pc   = (unsigned long) ka->sa.sa_handler;
 460                 regs->gr15 = 0;
 461         }
 462
 463         set_fs(USER_DS);
 464
 465         /* the tracer may want to single-step inside the handler */
 466         if (test_thread_flag(TIF_SINGLESTEP))
 467                 ptrace_notify(SIGTRAP);
 468
 469 #if DEBUG_SIG
 470         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 471                 sig, current->comm, current->pid, frame, regs->pc,
 472                frame->pretcode);
 473 #endif
 474
 475         return 1;
 476
 477 give_sigsegv:
 478         force_sig(SIGSEGV, current);
 479         return 0;
 480
 481 } /* end setup_rt_frame() */
 482
 483 /*****************************************************************************/
 484 /*
 485  * OK, we're invoking a handler
 486  */
 487 static int handle_signal(unsigned long sig, siginfo_t *info,
 488                          struct k_sigaction *ka, sigset_t *oldset,
 489                          struct pt_regs *regs)
 490 {
 491         int ret;
 492
 493         /* Are we from a system call? */
 494         if (in_syscall(regs)) {
 495                 /* If so, check system call restarting.. */
 496                 switch (regs->gr8) {
 497                 case -ERESTART_RESTARTBLOCK:
 498                 case -ERESTARTNOHAND:
 499                         regs->gr8 = -EINTR;
 500                         break;
 501
 502                 case -ERESTARTSYS:
 503                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 504                                 regs->gr8 = -EINTR;
 505                                 break;
 506                         }
 507
 508                         /* fallthrough */
 509                 case -ERESTARTNOINTR:
 510                         regs->gr8 = regs->orig_gr8;
 511                         regs->pc -= 4;
 512                 }
 513         }
 514
 515         /* Set up the stack frame */
 516         if (ka->sa.sa_flags & SA_SIGINFO)
 517                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 518         else
 519                 ret = setup_frame(sig, ka, oldset, regs);
 520
 521         if (ret) {
 522                 spin_lock_irq(&current->sighand->siglock);
 523                 sigorsets(&current->blocked, &current->blocked,
 524                           &ka->sa.sa_mask);
 525                 if (!(ka->sa.sa_flags & SA_NODEFER))
 526                         sigaddset(&current->blocked, sig);
 527                 recalc_sigpending();
 528                 spin_unlock_irq(&current->sighand->siglock);
 529         }
 530
 531         return ret;
 532
 533 } /* end handle_signal() */
 534
 535 /*****************************************************************************/
 536 /*
 537  * Note that 'init' is a special process: it doesn't get signals it doesn't
 538  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 539  * mistake.
 540  */
 541 int do_signal(struct pt_regs *regs, sigset_t *oldset)
 542 {
 543         struct k_sigaction ka;
 544         siginfo_t info;
 545         int signr;
 546
 547         /*
 548          * We want the common case to go fast, which
 549          * is why we may in certain cases get here from
 550          * kernel mode. Just return without doing anything
 551          * if so.
 552          */
 553         if (!user_mode(regs))
 554                 return 1;
 555
 556         if (try_to_freeze())
 557                 goto no_signal;
 558
 559         if (!oldset)
 560                 oldset = &current->blocked;
 561
 562         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 563         if (signr > 0)
 564                 return handle_signal(signr, &info, &ka, oldset, regs);
 565
 566 no_signal:
 567         /* Did we come from a system call? */
 568         if (regs->syscallno >= 0) {
 569                 /* Restart the system call - no handlers present */
 570                 if (regs->gr8 == -ERESTARTNOHAND ||
 571                     regs->gr8 == -ERESTARTSYS ||
 572                     regs->gr8 == -ERESTARTNOINTR) {
 573                         regs->gr8 = regs->orig_gr8;
 574                         regs->pc -= 4;
 575                 }
 576
 577                 if (regs->gr8 == -ERESTART_RESTARTBLOCK){
 578                         regs->gr8 = __NR_restart_syscall;
 579                         regs->pc -= 4;
 580                 }
 581         }
 582
 583         return 0;
 584
 585 } /* end do_signal() */
 586
 587 /*****************************************************************************/
 588 /*
 589  * notification of userspace execution resumption
 590  * - triggered by current->work.notify_resume
 591  */
 592 asmlinkage void do_notify_resume(__u32 thread_info_flags)
 593 {
 594         /* pending single-step? */
 595         if (thread_info_flags & _TIF_SINGLESTEP)
 596                 clear_thread_flag(TIF_SINGLESTEP);
 597
 598         /* deal with pending signal delivery */
 599         if (thread_info_flags & _TIF_SIGPENDING)
 600                 do_signal(__frame, NULL);
 601
 602 } /* end do_notify_resume() */