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                         return -EFAULT;
  70                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  71                 __get_user(mask, &act->sa_mask);
  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                         return -EFAULT;
  82                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  83                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  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         if (is_using_fpu(current))
 106                 fpu_kill_state(current);
 107
 108 #define COPY(x) err |= __get_user(regs->x, &sc->x)
 109         COPY(d1); COPY(d2); COPY(d3);
 110         COPY(a0); COPY(a1); COPY(a2); COPY(a3);
 111         COPY(e0); COPY(e1); COPY(e2); COPY(e3);
 112         COPY(e4); COPY(e5); COPY(e6); COPY(e7);
 113         COPY(lar); COPY(lir);
 114         COPY(mdr); COPY(mdrq);
 115         COPY(mcvf); COPY(mcrl); COPY(mcrh);
 116         COPY(sp); COPY(pc);
 117 #undef COPY
 118
 119         {
 120                 unsigned int tmpflags;
 121 #ifndef CONFIG_MN10300_USING_JTAG
 122 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
 123                    EPSW_T | EPSW_nAR)
 124 #else
 125 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
 126                    EPSW_nAR)
 127 #endif
 128                 err |= __get_user(tmpflags, &sc->epsw);
 129                 regs->epsw = (regs->epsw & ~USER_EPSW) |
 130                   (tmpflags & USER_EPSW);
 131                 regs->orig_d0 = -1;             /* disable syscall checks */
 132         }
 133
 134         {
 135                 struct fpucontext *buf;
 136                 err |= __get_user(buf, &sc->fpucontext);
 137                 if (buf) {
 138                         if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
 139                                 goto badframe;
 140                         err |= fpu_restore_sigcontext(buf);
 141                 }
 142         }
 143
 144         err |= __get_user(*_d0, &sc->d0);
 145         return err;
 146
 147 badframe:
 148         return 1;
 149 }
 150
 151 /*
 152  * standard signal return syscall
 153  */
 154 asmlinkage long sys_sigreturn(void)
 155 {
 156         struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
 157         sigset_t set;
 158         long d0;
 159
 160         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 161                 goto badframe;
 162         if (__get_user(set.sig[0], &frame->sc.oldmask))
 163                 goto badframe;
 164
 165         if (_NSIG_WORDS > 1 &&
 166             __copy_from_user(&set.sig[1], &frame->extramask,
 167                              sizeof(frame->extramask)))
 168                 goto badframe;
 169
 170         sigdelsetmask(&set, ~_BLOCKABLE);
 171         spin_lock_irq(&current->sighand->siglock);
 172         current->blocked = set;
 173         recalc_sigpending();
 174         spin_unlock_irq(&current->sighand->siglock);
 175
 176         if (restore_sigcontext(__frame, &frame->sc, &d0))
 177                 goto badframe;
 178
 179         return d0;
 180
 181 badframe:
 182         force_sig(SIGSEGV, current);
 183         return 0;
 184 }
 185
 186 /*
 187  * realtime signal return syscall
 188  */
 189 asmlinkage long sys_rt_sigreturn(void)
 190 {
 191         struct rt_sigframe __user *frame =
 192                 (struct rt_sigframe __user *) __frame->sp;
 193         sigset_t set;
 194         unsigned long d0;
 195
 196         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 197                 goto badframe;
 198         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 199                 goto badframe;
 200
 201         sigdelsetmask(&set, ~_BLOCKABLE);
 202         spin_lock_irq(&current->sighand->siglock);
 203         current->blocked = set;
 204         recalc_sigpending();
 205         spin_unlock_irq(&current->sighand->siglock);
 206
 207         if (restore_sigcontext(__frame, &frame->uc.uc_mcontext, &d0))
 208                 goto badframe;
 209
 210         if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
 211                 goto badframe;
 212
 213         return d0;
 214
 215 badframe:
 216         force_sig(SIGSEGV, current);
 217         return 0;
 218 }
 219
 220 /*
 221  * store the userspace context into a signal frame
 222  */
 223 static int setup_sigcontext(struct sigcontext __user *sc,
 224                             struct fpucontext *fpuctx,
 225                             struct pt_regs *regs,
 226                             unsigned long mask)
 227 {
 228         int tmp, err = 0;
 229
 230 #define COPY(x) err |= __put_user(regs->x, &sc->x)
 231         COPY(d0); COPY(d1); COPY(d2); COPY(d3);
 232         COPY(a0); COPY(a1); COPY(a2); COPY(a3);
 233         COPY(e0); COPY(e1); COPY(e2); COPY(e3);
 234         COPY(e4); COPY(e5); COPY(e6); COPY(e7);
 235         COPY(lar); COPY(lir);
 236         COPY(mdr); COPY(mdrq);
 237         COPY(mcvf); COPY(mcrl); COPY(mcrh);
 238         COPY(sp); COPY(epsw); COPY(pc);
 239 #undef COPY
 240
 241         tmp = fpu_setup_sigcontext(fpuctx);
 242         if (tmp < 0)
 243                 err = 1;
 244         else
 245                 err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);
 246
 247         /* non-iBCS2 extensions.. */
 248         err |= __put_user(mask, &sc->oldmask);
 249
 250         return err;
 251 }
 252
 253 /*
 254  * determine which stack to use..
 255  */
 256 static inline void __user *get_sigframe(struct k_sigaction *ka,
 257                                         struct pt_regs *regs,
 258                                         size_t frame_size)
 259 {
 260         unsigned long sp;
 261
 262         /* default to using normal stack */
 263         sp = regs->sp;
 264
 265         /* this is the X/Open sanctioned signal stack switching.  */
 266         if (ka->sa.sa_flags & SA_ONSTACK) {
 267                 if (!on_sig_stack(sp))
 268                         sp = current->sas_ss_sp + current->sas_ss_size;
 269         }
 270
 271         return (void __user *) ((sp - frame_size) & ~7UL);
 272 }
 273
 274 /*
 275  * set up a normal signal frame
 276  */
 277 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 278                        struct pt_regs *regs)
 279 {
 280         struct sigframe __user *frame;
 281         int rsig;
 282
 283         frame = get_sigframe(ka, regs, sizeof(*frame));
 284
 285         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 286                 goto give_sigsegv;
 287
 288         rsig = sig;
 289         if (sig < 32 &&
 290             current_thread_info()->exec_domain &&
 291             current_thread_info()->exec_domain->signal_invmap)
 292                 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
 293
 294         if (__put_user(rsig, &frame->sig) < 0 ||
 295             __put_user(&frame->sc, &frame->psc) < 0)
 296                 goto give_sigsegv;
 297
 298         if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
 299                 goto give_sigsegv;
 300
 301         if (_NSIG_WORDS > 1) {
 302                 if (__copy_to_user(frame->extramask, &set->sig[1],
 303                                    sizeof(frame->extramask)))
 304                         goto give_sigsegv;
 305         }
 306
 307         /* set up to return from userspace.  If provided, use a stub already in
 308          * userspace */
 309         if (ka->sa.sa_flags & SA_RESTORER) {
 310                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 311                         goto give_sigsegv;
 312         } else {
 313                 if (__put_user((void (*)(void))frame->retcode,
 314                                &frame->pretcode))
 315                         goto give_sigsegv;
 316                 /* this is mov $,d0; syscall 0 */
 317                 if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
 318                     __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
 319                     __put_user(0x00, (char *)(frame->retcode + 2)) ||
 320                     __put_user(0xf0, (char *)(frame->retcode + 3)) ||
 321                     __put_user(0xe0, (char *)(frame->retcode + 4)))
 322                         goto give_sigsegv;
 323                 flush_icache_range((unsigned long) frame->retcode,
 324                                    (unsigned long) frame->retcode + 5);
 325         }
 326
 327         /* set up registers for signal handler */
 328         regs->sp = (unsigned long) frame;
 329         regs->pc = (unsigned long) ka->sa.sa_handler;
 330         regs->d0 = sig;
 331         regs->d1 = (unsigned long) &frame->sc;
 332
 333         set_fs(USER_DS);
 334
 335         /* the tracer may want to single-step inside the handler */
 336         if (test_thread_flag(TIF_SINGLESTEP))
 337                 ptrace_notify(SIGTRAP);
 338
 339 #if DEBUG_SIG
 340         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 341                sig, current->comm, current->pid, frame, regs->pc,
 342                frame->pretcode);
 343 #endif
 344
 345         return 0;
 346
 347 give_sigsegv:
 348         force_sig(SIGSEGV, current);
 349         return -EFAULT;
 350 }
 351
 352 /*
 353  * set up a realtime signal frame
 354  */
 355 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 356                           sigset_t *set, struct pt_regs *regs)
 357 {
 358         struct rt_sigframe __user *frame;
 359         int rsig;
 360
 361         frame = get_sigframe(ka, regs, sizeof(*frame));
 362
 363         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 364                 goto give_sigsegv;
 365
 366         rsig = sig;
 367         if (sig < 32 &&
 368             current_thread_info()->exec_domain &&
 369             current_thread_info()->exec_domain->signal_invmap)
 370                 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
 371
 372         if (__put_user(rsig, &frame->sig) ||
 373             __put_user(&frame->info, &frame->pinfo) ||
 374             __put_user(&frame->uc, &frame->puc) ||
 375             copy_siginfo_to_user(&frame->info, info))
 376                 goto give_sigsegv;
 377
 378         /* create the ucontext.  */
 379         if (__put_user(0, &frame->uc.uc_flags) ||
 380             __put_user(0, &frame->uc.uc_link) ||
 381             __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 382             __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
 383             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size) ||
 384             setup_sigcontext(&frame->uc.uc_mcontext,
 385                              &frame->fpuctx, regs, set->sig[0]) ||
 386             __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 387                 goto give_sigsegv;
 388
 389         /* set up to return from userspace.  If provided, use a stub already in
 390          * userspace */
 391         if (ka->sa.sa_flags & SA_RESTORER) {
 392                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 393                         goto give_sigsegv;
 394         } else {
 395                 if (__put_user((void(*)(void))frame->retcode,
 396                                &frame->pretcode) ||
 397                     /* This is mov $,d0; syscall 0 */
 398                     __put_user(0x2c, (char *)(frame->retcode + 0)) ||
 399                     __put_user(__NR_rt_sigreturn,
 400                                (char *)(frame->retcode + 1)) ||
 401                     __put_user(0x00, (char *)(frame->retcode + 2)) ||
 402                     __put_user(0xf0, (char *)(frame->retcode + 3)) ||
 403                     __put_user(0xe0, (char *)(frame->retcode + 4)))
 404                         goto give_sigsegv;
 405
 406                 flush_icache_range((u_long) frame->retcode,
 407                                    (u_long) frame->retcode + 5);
 408         }
 409
 410         /* Set up registers for signal handler */
 411         regs->sp = (unsigned long) frame;
 412         regs->pc = (unsigned long) ka->sa.sa_handler;
 413         regs->d0 = sig;
 414         regs->d1 = (long) &frame->info;
 415
 416         set_fs(USER_DS);
 417
 418         /* the tracer may want to single-step inside the handler */
 419         if (test_thread_flag(TIF_SINGLESTEP))
 420                 ptrace_notify(SIGTRAP);
 421
 422 #if DEBUG_SIG
 423         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 424                sig, current->comm, current->pid, frame, regs->pc,
 425                frame->pretcode);
 426 #endif
 427
 428         return 0;
 429
 430 give_sigsegv:
 431         force_sig(SIGSEGV, current);
 432         return -EFAULT;
 433 }
 434
 435 /*
 436  * handle the actual delivery of a signal to userspace
 437  */
 438 static int handle_signal(int sig,
 439                          siginfo_t *info, struct k_sigaction *ka,
 440                          sigset_t *oldset, struct pt_regs *regs)
 441 {
 442         int ret;
 443
 444         /* Are we from a system call? */
 445         if (regs->orig_d0 >= 0) {
 446                 /* If so, check system call restarting.. */
 447                 switch (regs->d0) {
 448                 case -ERESTART_RESTARTBLOCK:
 449                 case -ERESTARTNOHAND:
 450                         regs->d0 = -EINTR;
 451                         break;
 452
 453                 case -ERESTARTSYS:
 454                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 455                                 regs->d0 = -EINTR;
 456                                 break;
 457                         }
 458
 459                         /* fallthrough */
 460                 case -ERESTARTNOINTR:
 461                         regs->d0 = regs->orig_d0;
 462                         regs->pc -= 2;
 463                 }
 464         }
 465
 466         /* Set up the stack frame */
 467         if (ka->sa.sa_flags & SA_SIGINFO)
 468                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 469         else
 470                 ret = setup_frame(sig, ka, oldset, regs);
 471
 472         if (ret == 0) {
 473                 spin_lock_irq(&current->sighand->siglock);
 474                 sigorsets(&current->blocked, &current->blocked,
 475                           &ka->sa.sa_mask);
 476                 if (!(ka->sa.sa_flags & SA_NODEFER))
 477                         sigaddset(&current->blocked, sig);
 478                 recalc_sigpending();
 479                 spin_unlock_irq(&current->sighand->siglock);
 480         }
 481
 482         return ret;
 483 }
 484
 485 /*
 486  * handle a potential signal
 487  */
 488 static void do_signal(struct pt_regs *regs)
 489 {
 490         struct k_sigaction ka;
 491         siginfo_t info;
 492         sigset_t *oldset;
 493         int signr;
 494
 495         /* we want the common case to go fast, which is why we may in certain
 496          * cases get here from kernel mode */
 497         if (!user_mode(regs))
 498                 return;
 499
 500         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 501                 oldset = &current->saved_sigmask;
 502         else
 503                 oldset = &current->blocked;
 504
 505         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 506         if (signr > 0) {
 507                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 508                         /* a signal was successfully delivered; the saved
 509                          * sigmask will have been stored in the signal frame,
 510                          * and will be restored by sigreturn, so we can simply
 511                          * clear the TIF_RESTORE_SIGMASK flag */
 512                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 513                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 514
 515                         tracehook_signal_handler(signr, &info, &ka, regs,
 516                                                  test_thread_flag(TIF_SINGLESTEP));
 517                 }
 518
 519                 return;
 520         }
 521
 522         /* did we come from a system call? */
 523         if (regs->orig_d0 >= 0) {
 524                 /* restart the system call - no handlers present */
 525                 switch (regs->d0) {
 526                 case -ERESTARTNOHAND:
 527                 case -ERESTARTSYS:
 528                 case -ERESTARTNOINTR:
 529                         regs->d0 = regs->orig_d0;
 530                         regs->pc -= 2;
 531                         break;
 532
 533                 case -ERESTART_RESTARTBLOCK:
 534                         regs->d0 = __NR_restart_syscall;
 535                         regs->pc -= 2;
 536                         break;
 537                 }
 538         }
 539
 540         /* if there's no signal to deliver, we just put the saved sigmask
 541          * back */
 542         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 543                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 544                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 545         }
 546 }
 547
 548 /*
 549  * notification of userspace execution resumption
 550  * - triggered by current->work.notify_resume
 551  */
 552 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 553 {
 554         /* Pending single-step? */
 555         if (thread_info_flags & _TIF_SINGLESTEP) {
 556 #ifndef CONFIG_MN10300_USING_JTAG
 557                 regs->epsw |= EPSW_T;
 558                 clear_thread_flag(TIF_SINGLESTEP);
 559 #else
 560                 BUG(); /* no h/w single-step if using JTAG unit */
 561 #endif
 562         }
 563
 564         /* deal with pending signal delivery */
 565         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 566                 do_signal(regs);
 567
 568         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 569                 clear_thread_flag(TIF_NOTIFY_RESUME);
 570                 tracehook_notify_resume(__frame);
 571                 if (current->replacement_session_keyring)
 572                         key_replace_session_keyring();
 573         }
 574 }