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         sigset_t blocked;
  42
  43         current->saved_sigmask = current->blocked;
  44
  45         mask &= _BLOCKABLE;
  46         siginitset(&blocked, mask);
  47         set_current_blocked(&blocked);
  48
  49         current->state = TASK_INTERRUPTIBLE;
  50         schedule();
  51         set_thread_flag(TIF_RESTORE_SIGMASK);
  52         return -ERESTARTNOHAND;
  53 }
  54
  55 /*
  56  * set signal action syscall
  57  */
  58 asmlinkage long sys_sigaction(int sig,
  59                               const struct old_sigaction __user *act,
  60                               struct old_sigaction __user *oact)
  61 {
  62         struct k_sigaction new_ka, old_ka;
  63         int ret;
  64
  65         if (act) {
  66                 old_sigset_t mask;
  67                 if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
  68                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  69                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
  70                     __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
  71                     __get_user(mask, &act->sa_mask))
  72                         return -EFAULT;
  73                 siginitset(&new_ka.sa.sa_mask, mask);
  74         }
  75
  76         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  77
  78         if (!ret && oact) {
  79                 if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
  80                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  81                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
  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                         return -EFAULT;
  85         }
  86
  87         return ret;
  88 }
  89
  90 /*
  91  * set alternate signal stack syscall
  92  */
  93 asmlinkage long sys_sigaltstack(const stack_t __user *uss, stack_t *uoss)
  94 {
  95         return do_sigaltstack(uss, uoss, current_frame()->sp);
  96 }
  97
  98 /*
  99  * do a signal return; undo the signal stack.
 100  */
 101 static int restore_sigcontext(struct pt_regs *regs,
 102                               struct sigcontext __user *sc, long *_d0)
 103 {
 104         unsigned int err = 0;
 105
 106         /* Always make any pending restarted system calls return -EINTR */
 107         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 108
 109         if (is_using_fpu(current))
 110                 fpu_kill_state(current);
 111
 112 #define COPY(x) err |= __get_user(regs->x, &sc->x)
 113         COPY(d1); COPY(d2); COPY(d3);
 114         COPY(a0); COPY(a1); COPY(a2); COPY(a3);
 115         COPY(e0); COPY(e1); COPY(e2); COPY(e3);
 116         COPY(e4); COPY(e5); COPY(e6); COPY(e7);
 117         COPY(lar); COPY(lir);
 118         COPY(mdr); COPY(mdrq);
 119         COPY(mcvf); COPY(mcrl); COPY(mcrh);
 120         COPY(sp); COPY(pc);
 121 #undef COPY
 122
 123         {
 124                 unsigned int tmpflags;
 125 #ifndef CONFIG_MN10300_USING_JTAG
 126 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
 127                    EPSW_T | EPSW_nAR)
 128 #else
 129 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
 130                    EPSW_nAR)
 131 #endif
 132                 err |= __get_user(tmpflags, &sc->epsw);
 133                 regs->epsw = (regs->epsw & ~USER_EPSW) |
 134                   (tmpflags & USER_EPSW);
 135                 regs->orig_d0 = -1;             /* disable syscall checks */
 136         }
 137
 138         {
 139                 struct fpucontext *buf;
 140                 err |= __get_user(buf, &sc->fpucontext);
 141                 if (buf) {
 142                         if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
 143                                 goto badframe;
 144                         err |= fpu_restore_sigcontext(buf);
 145                 }
 146         }
 147
 148         err |= __get_user(*_d0, &sc->d0);
 149         return err;
 150
 151 badframe:
 152         return 1;
 153 }
 154
 155 /*
 156  * standard signal return syscall
 157  */
 158 asmlinkage long sys_sigreturn(void)
 159 {
 160         struct sigframe __user *frame;
 161         sigset_t set;
 162         long d0;
 163
 164         frame = (struct sigframe __user *) current_frame()->sp;
 165         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 166                 goto badframe;
 167         if (__get_user(set.sig[0], &frame->sc.oldmask))
 168                 goto badframe;
 169
 170         if (_NSIG_WORDS > 1 &&
 171             __copy_from_user(&set.sig[1], &frame->extramask,
 172                              sizeof(frame->extramask)))
 173                 goto badframe;
 174
 175         sigdelsetmask(&set, ~_BLOCKABLE);
 176         set_current_blocked(&set);
 177
 178         if (restore_sigcontext(current_frame(), &frame->sc, &d0))
 179                 goto badframe;
 180
 181         return d0;
 182
 183 badframe:
 184         force_sig(SIGSEGV, current);
 185         return 0;
 186 }
 187
 188 /*
 189  * realtime signal return syscall
 190  */
 191 asmlinkage long sys_rt_sigreturn(void)
 192 {
 193         struct rt_sigframe __user *frame;
 194         sigset_t set;
 195         long d0;
 196
 197         frame = (struct rt_sigframe __user *) current_frame()->sp;
 198         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 199                 goto badframe;
 200         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 201                 goto badframe;
 202
 203         sigdelsetmask(&set, ~_BLOCKABLE);
 204         set_current_blocked(&set);
 205
 206         if (restore_sigcontext(current_frame(), &frame->uc.uc_mcontext, &d0))
 207                 goto badframe;
 208
 209         if (do_sigaltstack(&frame->uc.uc_stack, NULL, current_frame()->sp) ==
 210             -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 (sas_ss_flags(sp) == 0)
 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         /* the tracer may want to single-step inside the handler */
 334         if (test_thread_flag(TIF_SINGLESTEP))
 335                 ptrace_notify(SIGTRAP);
 336
 337 #if DEBUG_SIG
 338         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 339                sig, current->comm, current->pid, frame, regs->pc,
 340                frame->pretcode);
 341 #endif
 342
 343         return 0;
 344
 345 give_sigsegv:
 346         force_sigsegv(sig, current);
 347         return -EFAULT;
 348 }
 349
 350 /*
 351  * set up a realtime signal frame
 352  */
 353 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 354                           sigset_t *set, struct pt_regs *regs)
 355 {
 356         struct rt_sigframe __user *frame;
 357         int rsig;
 358
 359         frame = get_sigframe(ka, regs, sizeof(*frame));
 360
 361         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 362                 goto give_sigsegv;
 363
 364         rsig = sig;
 365         if (sig < 32 &&
 366             current_thread_info()->exec_domain &&
 367             current_thread_info()->exec_domain->signal_invmap)
 368                 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
 369
 370         if (__put_user(rsig, &frame->sig) ||
 371             __put_user(&frame->info, &frame->pinfo) ||
 372             __put_user(&frame->uc, &frame->puc) ||
 373             copy_siginfo_to_user(&frame->info, info))
 374                 goto give_sigsegv;
 375
 376         /* create the ucontext.  */
 377         if (__put_user(0, &frame->uc.uc_flags) ||
 378             __put_user(0, &frame->uc.uc_link) ||
 379             __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 380             __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
 381             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size) ||
 382             setup_sigcontext(&frame->uc.uc_mcontext,
 383                              &frame->fpuctx, regs, set->sig[0]) ||
 384             __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 385                 goto give_sigsegv;
 386
 387         /* set up to return from userspace.  If provided, use a stub already in
 388          * userspace */
 389         if (ka->sa.sa_flags & SA_RESTORER) {
 390                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 391                         goto give_sigsegv;
 392         } else {
 393                 if (__put_user((void(*)(void))frame->retcode,
 394                                &frame->pretcode) ||
 395                     /* This is mov $,d0; syscall 0 */
 396                     __put_user(0x2c, (char *)(frame->retcode + 0)) ||
 397                     __put_user(__NR_rt_sigreturn,
 398                                (char *)(frame->retcode + 1)) ||
 399                     __put_user(0x00, (char *)(frame->retcode + 2)) ||
 400                     __put_user(0xf0, (char *)(frame->retcode + 3)) ||
 401                     __put_user(0xe0, (char *)(frame->retcode + 4)))
 402                         goto give_sigsegv;
 403
 404                 flush_icache_range((u_long) frame->retcode,
 405                                    (u_long) frame->retcode + 5);
 406         }
 407
 408         /* Set up registers for signal handler */
 409         regs->sp = (unsigned long) frame;
 410         regs->pc = (unsigned long) ka->sa.sa_handler;
 411         regs->d0 = sig;
 412         regs->d1 = (long) &frame->info;
 413
 414         /* the tracer may want to single-step inside the handler */
 415         if (test_thread_flag(TIF_SINGLESTEP))
 416                 ptrace_notify(SIGTRAP);
 417
 418 #if DEBUG_SIG
 419         printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 420                sig, current->comm, current->pid, frame, regs->pc,
 421                frame->pretcode);
 422 #endif
 423
 424         return 0;
 425
 426 give_sigsegv:
 427         force_sigsegv(sig, current);
 428         return -EFAULT;
 429 }
 430
 431 static inline void stepback(struct pt_regs *regs)
 432 {
 433         regs->pc -= 2;
 434         regs->orig_d0 = -1;
 435 }
 436
 437 /*
 438  * handle the actual delivery of a signal to userspace
 439  */
 440 static int handle_signal(int sig,
 441                          siginfo_t *info, struct k_sigaction *ka,
 442                          sigset_t *oldset, struct pt_regs *regs)
 443 {
 444         int ret;
 445
 446         /* Are we from a system call? */
 447         if (regs->orig_d0 >= 0) {
 448                 /* If so, check system call restarting.. */
 449                 switch (regs->d0) {
 450                 case -ERESTART_RESTARTBLOCK:
 451                 case -ERESTARTNOHAND:
 452                         regs->d0 = -EINTR;
 453                         break;
 454
 455                 case -ERESTARTSYS:
 456                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 457                                 regs->d0 = -EINTR;
 458                                 break;
 459                         }
 460
 461                         /* fallthrough */
 462                 case -ERESTARTNOINTR:
 463                         regs->d0 = regs->orig_d0;
 464                         stepback(regs);
 465                 }
 466         }
 467
 468         /* Set up the stack frame */
 469         if (ka->sa.sa_flags & SA_SIGINFO)
 470                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 471         else
 472                 ret = setup_frame(sig, ka, oldset, regs);
 473
 474         if (ret == 0)
 475                 block_sigmask(ka, sig);
 476
 477         return ret;
 478 }
 479
 480 /*
 481  * handle a potential signal
 482  */
 483 static void do_signal(struct pt_regs *regs)
 484 {
 485         struct k_sigaction ka;
 486         siginfo_t info;
 487         sigset_t *oldset;
 488         int signr;
 489
 490         /* we want the common case to go fast, which is why we may in certain
 491          * cases get here from kernel mode */
 492         if (!user_mode(regs))
 493                 return;
 494
 495         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 496                 oldset = &current->saved_sigmask;
 497         else
 498                 oldset = &current->blocked;
 499
 500         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 501         if (signr > 0) {
 502                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 503                         /* a signal was successfully delivered; the saved
 504                          * sigmask will have been stored in the signal frame,
 505                          * and will be restored by sigreturn, so we can simply
 506                          * clear the TIF_RESTORE_SIGMASK flag */
 507                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 508                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 509
 510                         tracehook_signal_handler(signr, &info, &ka, regs,
 511                                                  test_thread_flag(TIF_SINGLESTEP));
 512                 }
 513
 514                 return;
 515         }
 516
 517         /* did we come from a system call? */
 518         if (regs->orig_d0 >= 0) {
 519                 /* restart the system call - no handlers present */
 520                 switch (regs->d0) {
 521                 case -ERESTARTNOHAND:
 522                 case -ERESTARTSYS:
 523                 case -ERESTARTNOINTR:
 524                         regs->d0 = regs->orig_d0;
 525                         stepback(regs);
 526                         break;
 527
 528                 case -ERESTART_RESTARTBLOCK:
 529                         regs->d0 = __NR_restart_syscall;
 530                         stepback(regs);
 531                         break;
 532                 }
 533         }
 534
 535         /* if there's no signal to deliver, we just put the saved sigmask
 536          * back */
 537         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 538                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 539                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 540         }
 541 }
 542
 543 /*
 544  * notification of userspace execution resumption
 545  * - triggered by current->work.notify_resume
 546  */
 547 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 548 {
 549         /* Pending single-step? */
 550         if (thread_info_flags & _TIF_SINGLESTEP) {
 551 #ifndef CONFIG_MN10300_USING_JTAG
 552                 regs->epsw |= EPSW_T;
 553                 clear_thread_flag(TIF_SINGLESTEP);
 554 #else
 555                 BUG(); /* no h/w single-step if using JTAG unit */
 556 #endif
 557         }
 558
 559         /* deal with pending signal delivery */
 560         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 561                 do_signal(regs);
 562
 563         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 564                 clear_thread_flag(TIF_NOTIFY_RESUME);
 565                 tracehook_notify_resume(current_frame());
 566                 if (current->replacement_session_keyring)
 567                         key_replace_session_keyring();
 568         }
 569 }