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, current_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;
 160         sigset_t set;
 161         long d0;
 162
 163         frame = (struct sigframe __user *) current_frame()->sp;
 164         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 165                 goto badframe;
 166         if (__get_user(set.sig[0], &frame->sc.oldmask))
 167                 goto badframe;
 168
 169         if (_NSIG_WORDS > 1 &&
 170             __copy_from_user(&set.sig[1], &frame->extramask,
 171                              sizeof(frame->extramask)))
 172                 goto badframe;
 173
 174         sigdelsetmask(&set, ~_BLOCKABLE);
 175         spin_lock_irq(&current->sighand->siglock);
 176         current->blocked = set;
 177         recalc_sigpending();
 178         spin_unlock_irq(&current->sighand->siglock);
 179
 180         if (restore_sigcontext(current_frame(), &frame->sc, &d0))
 181                 goto badframe;
 182
 183         return d0;
 184
 185 badframe:
 186         force_sig(SIGSEGV, current);
 187         return 0;
 188 }
 189
 190 /*
 191  * realtime signal return syscall
 192  */
 193 asmlinkage long sys_rt_sigreturn(void)
 194 {
 195         struct rt_sigframe __user *frame;
 196         sigset_t set;
 197         long d0;
 198
 199         frame = (struct rt_sigframe __user *) current_frame()->sp;
 200         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 201                 goto badframe;
 202         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 203                 goto badframe;
 204
 205         sigdelsetmask(&set, ~_BLOCKABLE);
 206         spin_lock_irq(&current->sighand->siglock);
 207         current->blocked = set;
 208         recalc_sigpending();
 209         spin_unlock_irq(&current->sighand->siglock);
 210
 211         if (restore_sigcontext(current_frame(), &frame->uc.uc_mcontext, &d0))
 212                 goto badframe;
 213
 214         if (do_sigaltstack(&frame->uc.uc_stack, NULL, current_frame()->sp) ==
 215             -EFAULT)
 216                 goto badframe;
 217
 218         return d0;
 219
 220 badframe:
 221         force_sig(SIGSEGV, current);
 222         return 0;
 223 }
 224
 225 /*
 226  * store the userspace context into a signal frame
 227  */
 228 static int setup_sigcontext(struct sigcontext __user *sc,
 229                             struct fpucontext *fpuctx,
 230                             struct pt_regs *regs,
 231                             unsigned long mask)
 232 {
 233         int tmp, err = 0;
 234
 235 #define COPY(x) err |= __put_user(regs->x, &sc->x)
 236         COPY(d0); COPY(d1); COPY(d2); COPY(d3);
 237         COPY(a0); COPY(a1); COPY(a2); COPY(a3);
 238         COPY(e0); COPY(e1); COPY(e2); COPY(e3);
 239         COPY(e4); COPY(e5); COPY(e6); COPY(e7);
 240         COPY(lar); COPY(lir);
 241         COPY(mdr); COPY(mdrq);
 242         COPY(mcvf); COPY(mcrl); COPY(mcrh);
 243         COPY(sp); COPY(epsw); COPY(pc);
 244 #undef COPY
 245
 246         tmp = fpu_setup_sigcontext(fpuctx);
 247         if (tmp < 0)
 248                 err = 1;
 249         else
 250                 err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);
 251
 252         /* non-iBCS2 extensions.. */
 253         err |= __put_user(mask, &sc->oldmask);
 254
 255         return err;
 256 }
 257
 258 /*
 259  * determine which stack to use..
 260  */
 261 static inline void __user *get_sigframe(struct k_sigaction *ka,
 262                                         struct pt_regs *regs,
 263                                         size_t frame_size)
 264 {
 265         unsigned long sp;
 266
 267         /* default to using normal stack */
 268         sp = regs->sp;
 269
 270         /* this is the X/Open sanctioned signal stack switching.  */
 271         if (ka->sa.sa_flags & SA_ONSTACK) {
 272                 if (sas_ss_flags(sp) == 0)
 273                         sp = current->sas_ss_sp + current->sas_ss_size;
 274         }
 275
 276         return (void __user *) ((sp - frame_size) & ~7UL);
 277 }
 278
 279 /*
 280  * set up a normal signal frame
 281  */
 282 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 283                        struct pt_regs *regs)
 284 {
 285         struct sigframe __user *frame;
 286         int rsig;
 287
 288         frame = get_sigframe(ka, regs, sizeof(*frame));
 289
 290         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 291                 goto give_sigsegv;
 292
 293         rsig = sig;
 294         if (sig < 32 &&
 295             current_thread_info()->exec_domain &&
 296             current_thread_info()->exec_domain->signal_invmap)
 297                 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
 298
 299         if (__put_user(rsig, &frame->sig) < 0 ||
 300             __put_user(&frame->sc, &frame->psc) < 0)
 301                 goto give_sigsegv;
 302
 303         if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
 304                 goto give_sigsegv;
 305
 306         if (_NSIG_WORDS > 1) {
 307                 if (__copy_to_user(frame->extramask, &set->sig[1],
 308                                    sizeof(frame->extramask)))
 309                         goto give_sigsegv;
 310         }
 311
 312         /* set up to return from userspace.  If provided, use a stub already in
 313          * userspace */
 314         if (ka->sa.sa_flags & SA_RESTORER) {
 315                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 316                         goto give_sigsegv;
 317         } else {
 318                 if (__put_user((void (*)(void))frame->retcode,
 319                                &frame->pretcode))
 320                         goto give_sigsegv;
 321                 /* this is mov $,d0; syscall 0 */
 322                 if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
 323                     __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
 324                     __put_user(0x00, (char *)(frame->retcode + 2)) ||
 325                     __put_user(0xf0, (char *)(frame->retcode + 3)) ||
 326                     __put_user(0xe0, (char *)(frame->retcode + 4)))
 327                         goto give_sigsegv;
 328                 flush_icache_range((unsigned long) frame->retcode,
 329                                    (unsigned long) frame->retcode + 5);
 330         }
 331
 332         /* set up registers for signal handler */
 333         regs->sp = (unsigned long) frame;
 334         regs->pc = (unsigned long) ka->sa.sa_handler;
 335         regs->d0 = sig;
 336         regs->d1 = (unsigned long) &frame->sc;
 337
 338         /* the tracer may want to single-step inside the handler */
 339         if (test_thread_flag(TIF_SINGLESTEP))
 340                 ptrace_notify(SIGTRAP);
 341
 342 #if DEBUG_SIG
 343         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 344                sig, current->comm, current->pid, frame, regs->pc,
 345                frame->pretcode);
 346 #endif
 347
 348         return 0;
 349
 350 give_sigsegv:
 351         force_sigsegv(sig, current);
 352         return -EFAULT;
 353 }
 354
 355 /*
 356  * set up a realtime signal frame
 357  */
 358 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 359                           sigset_t *set, struct pt_regs *regs)
 360 {
 361         struct rt_sigframe __user *frame;
 362         int rsig;
 363
 364         frame = get_sigframe(ka, regs, sizeof(*frame));
 365
 366         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 367                 goto give_sigsegv;
 368
 369         rsig = sig;
 370         if (sig < 32 &&
 371             current_thread_info()->exec_domain &&
 372             current_thread_info()->exec_domain->signal_invmap)
 373                 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
 374
 375         if (__put_user(rsig, &frame->sig) ||
 376             __put_user(&frame->info, &frame->pinfo) ||
 377             __put_user(&frame->uc, &frame->puc) ||
 378             copy_siginfo_to_user(&frame->info, info))
 379                 goto give_sigsegv;
 380
 381         /* create the ucontext.  */
 382         if (__put_user(0, &frame->uc.uc_flags) ||
 383             __put_user(0, &frame->uc.uc_link) ||
 384             __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 385             __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
 386             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size) ||
 387             setup_sigcontext(&frame->uc.uc_mcontext,
 388                              &frame->fpuctx, regs, set->sig[0]) ||
 389             __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 390                 goto give_sigsegv;
 391
 392         /* set up to return from userspace.  If provided, use a stub already in
 393          * userspace */
 394         if (ka->sa.sa_flags & SA_RESTORER) {
 395                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 396                         goto give_sigsegv;
 397         } else {
 398                 if (__put_user((void(*)(void))frame->retcode,
 399                                &frame->pretcode) ||
 400                     /* This is mov $,d0; syscall 0 */
 401                     __put_user(0x2c, (char *)(frame->retcode + 0)) ||
 402                     __put_user(__NR_rt_sigreturn,
 403                                (char *)(frame->retcode + 1)) ||
 404                     __put_user(0x00, (char *)(frame->retcode + 2)) ||
 405                     __put_user(0xf0, (char *)(frame->retcode + 3)) ||
 406                     __put_user(0xe0, (char *)(frame->retcode + 4)))
 407                         goto give_sigsegv;
 408
 409                 flush_icache_range((u_long) frame->retcode,
 410                                    (u_long) frame->retcode + 5);
 411         }
 412
 413         /* Set up registers for signal handler */
 414         regs->sp = (unsigned long) frame;
 415         regs->pc = (unsigned long) ka->sa.sa_handler;
 416         regs->d0 = sig;
 417         regs->d1 = (long) &frame->info;
 418
 419         /* the tracer may want to single-step inside the handler */
 420         if (test_thread_flag(TIF_SINGLESTEP))
 421                 ptrace_notify(SIGTRAP);
 422
 423 #if DEBUG_SIG
 424         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 425                sig, current->comm, current->pid, frame, regs->pc,
 426                frame->pretcode);
 427 #endif
 428
 429         return 0;
 430
 431 give_sigsegv:
 432         force_sigsegv(sig, current);
 433         return -EFAULT;
 434 }
 435
 436 static inline void stepback(struct pt_regs *regs)
 437 {
 438         regs->pc -= 2;
 439         regs->orig_d0 = -1;
 440 }
 441
 442 /*
 443  * handle the actual delivery of a signal to userspace
 444  */
 445 static int handle_signal(int sig,
 446                          siginfo_t *info, struct k_sigaction *ka,
 447                          sigset_t *oldset, struct pt_regs *regs)
 448 {
 449         int ret;
 450
 451         /* Are we from a system call? */
 452         if (regs->orig_d0 >= 0) {
 453                 /* If so, check system call restarting.. */
 454                 switch (regs->d0) {
 455                 case -ERESTART_RESTARTBLOCK:
 456                 case -ERESTARTNOHAND:
 457                         regs->d0 = -EINTR;
 458                         break;
 459
 460                 case -ERESTARTSYS:
 461                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 462                                 regs->d0 = -EINTR;
 463                                 break;
 464                         }
 465
 466                         /* fallthrough */
 467                 case -ERESTARTNOINTR:
 468                         regs->d0 = regs->orig_d0;
 469                         stepback(regs);
 470                 }
 471         }
 472
 473         /* Set up the stack frame */
 474         if (ka->sa.sa_flags & SA_SIGINFO)
 475                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 476         else
 477                 ret = setup_frame(sig, ka, oldset, regs);
 478
 479         if (ret == 0) {
 480                 spin_lock_irq(&current->sighand->siglock);
 481                 sigorsets(&current->blocked, &current->blocked,
 482                           &ka->sa.sa_mask);
 483                 if (!(ka->sa.sa_flags & SA_NODEFER))
 484                         sigaddset(&current->blocked, sig);
 485                 recalc_sigpending();
 486                 spin_unlock_irq(&current->sighand->siglock);
 487         }
 488
 489         return ret;
 490 }
 491
 492 /*
 493  * handle a potential signal
 494  */
 495 static void do_signal(struct pt_regs *regs)
 496 {
 497         struct k_sigaction ka;
 498         siginfo_t info;
 499         sigset_t *oldset;
 500         int signr;
 501
 502         /* we want the common case to go fast, which is why we may in certain
 503          * cases get here from kernel mode */
 504         if (!user_mode(regs))
 505                 return;
 506
 507         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 508                 oldset = &current->saved_sigmask;
 509         else
 510                 oldset = &current->blocked;
 511
 512         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 513         if (signr > 0) {
 514                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 515                         /* a signal was successfully delivered; the saved
 516                          * sigmask will have been stored in the signal frame,
 517                          * and will be restored by sigreturn, so we can simply
 518                          * clear the TIF_RESTORE_SIGMASK flag */
 519                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 520                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 521
 522                         tracehook_signal_handler(signr, &info, &ka, regs,
 523                                                  test_thread_flag(TIF_SINGLESTEP));
 524                 }
 525
 526                 return;
 527         }
 528
 529         /* did we come from a system call? */
 530         if (regs->orig_d0 >= 0) {
 531                 /* restart the system call - no handlers present */
 532                 switch (regs->d0) {
 533                 case -ERESTARTNOHAND:
 534                 case -ERESTARTSYS:
 535                 case -ERESTARTNOINTR:
 536                         regs->d0 = regs->orig_d0;
 537                         stepback(regs);
 538                         break;
 539
 540                 case -ERESTART_RESTARTBLOCK:
 541                         regs->d0 = __NR_restart_syscall;
 542                         stepback(regs);
 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
 555 /*
 556  * notification of userspace execution resumption
 557  * - triggered by current->work.notify_resume
 558  */
 559 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 560 {
 561         /* Pending single-step? */
 562         if (thread_info_flags & _TIF_SINGLESTEP) {
 563 #ifndef CONFIG_MN10300_USING_JTAG
 564                 regs->epsw |= EPSW_T;
 565                 clear_thread_flag(TIF_SINGLESTEP);
 566 #else
 567                 BUG(); /* no h/w single-step if using JTAG unit */
 568 #endif
 569         }
 570
 571         /* deal with pending signal delivery */
 572         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 573                 do_signal(regs);
 574
 575         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 576                 clear_thread_flag(TIF_NOTIFY_RESUME);
 577                 tracehook_notify_resume(current_frame());
 578                 if (current->replacement_session_keyring)
 579                         key_replace_session_keyring();
 580         }
 581 }