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/kernel.h>
  17 #include <linux/signal.h>
  18 #include <linux/errno.h>
  19 #include <linux/wait.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/unistd.h>
  22 #include <linux/personality.h>
  23 #include <linux/tracehook.h>
  24 #include <asm/ucontext.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/cacheflush.h>
  27
  28 #define DEBUG_SIG 0
  29
  30 struct fdpic_func_descriptor {
  31         unsigned long   text;
  32         unsigned long   GOT;
  33 };
  34
  35 /*
  36  * Atomically swap in the new signal mask, and wait for a signal.
  37  */
  38 asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  39 {
  40         sigset_t blocked;
  41         siginitset(&blocked, mask);
  42         return sigsuspend(&blocked);
  43 }
  44
  45 asmlinkage int sys_sigaction(int sig,
  46                              const struct old_sigaction __user *act,
  47                              struct old_sigaction __user *oact)
  48 {
  49         struct k_sigaction new_ka, old_ka;
  50         int ret;
  51
  52         if (act) {
  53                 old_sigset_t mask;
  54                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  55                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  56                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
  57                     __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
  58                     __get_user(mask, &act->sa_mask))
  59                         return -EFAULT;
  60                 siginitset(&new_ka.sa.sa_mask, mask);
  61         }
  62
  63         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  64
  65         if (!ret && oact) {
  66                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  67                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  68                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
  69                     __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
  70                     __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
  71                         return -EFAULT;
  72         }
  73
  74         return ret;
  75 }
  76
  77 asmlinkage
  78 int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
  79 {
  80         return do_sigaltstack(uss, uoss, __frame->sp);
  81 }
  82
  83
  84 /*
  85  * Do a signal return; undo the signal stack.
  86  */
  87
  88 struct sigframe
  89 {
  90         __sigrestore_t pretcode;
  91         int sig;
  92         struct sigcontext sc;
  93         unsigned long extramask[_NSIG_WORDS-1];
  94         uint32_t retcode[2];
  95 };
  96
  97 struct rt_sigframe
  98 {
  99         __sigrestore_t pretcode;
 100         int sig;
 101         struct siginfo __user *pinfo;
 102         void __user *puc;
 103         struct siginfo info;
 104         struct ucontext uc;
 105         uint32_t retcode[2];
 106 };
 107
 108 static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
 109 {
 110         struct user_context *user = current->thread.user;
 111         unsigned long tbr, psr;
 112
 113         /* Always make any pending restarted system calls return -EINTR */
 114         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 115
 116         tbr = user->i.tbr;
 117         psr = user->i.psr;
 118         if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
 119                 goto badframe;
 120         user->i.tbr = tbr;
 121         user->i.psr = psr;
 122
 123         restore_user_regs(user);
 124
 125         user->i.syscallno = -1;         /* disable syscall checks */
 126
 127         *_gr8 = user->i.gr[8];
 128         return 0;
 129
 130  badframe:
 131         return 1;
 132 }
 133
 134 asmlinkage int sys_sigreturn(void)
 135 {
 136         struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
 137         sigset_t set;
 138         int gr8;
 139
 140         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 141                 goto badframe;
 142         if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
 143                 goto badframe;
 144
 145         if (_NSIG_WORDS > 1 &&
 146             __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
 147                 goto badframe;
 148
 149         set_current_blocked(&set);
 150
 151         if (restore_sigcontext(&frame->sc, &gr8))
 152                 goto badframe;
 153         return gr8;
 154
 155  badframe:
 156         force_sig(SIGSEGV, current);
 157         return 0;
 158 }
 159
 160 asmlinkage int sys_rt_sigreturn(void)
 161 {
 162         struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
 163         sigset_t set;
 164         int gr8;
 165
 166         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 167                 goto badframe;
 168         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 169                 goto badframe;
 170
 171         set_current_blocked(&set);
 172
 173         if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
 174                 goto badframe;
 175
 176         if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
 177                 goto badframe;
 178
 179         return gr8;
 180
 181 badframe:
 182         force_sig(SIGSEGV, current);
 183         return 0;
 184 }
 185
 186 /*
 187  * Set up a signal frame
 188  */
 189 static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
 190 {
 191         save_user_regs(current->thread.user);
 192
 193         if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
 194                 goto badframe;
 195
 196         /* non-iBCS2 extensions.. */
 197         if (__put_user(mask, &sc->sc_oldmask) < 0)
 198                 goto badframe;
 199
 200         return 0;
 201
 202  badframe:
 203         return 1;
 204 }
 205
 206 /*****************************************************************************/
 207 /*
 208  * Determine which stack to use..
 209  */
 210 static inline void __user *get_sigframe(struct k_sigaction *ka,
 211                                         size_t frame_size)
 212 {
 213         unsigned long sp;
 214
 215         /* Default to using normal stack */
 216         sp = __frame->sp;
 217
 218         /* This is the X/Open sanctioned signal stack switching.  */
 219         if (ka->sa.sa_flags & SA_ONSTACK) {
 220                 if (! sas_ss_flags(sp))
 221                         sp = current->sas_ss_sp + current->sas_ss_size;
 222         }
 223
 224         return (void __user *) ((sp - frame_size) & ~7UL);
 225
 226 } /* end get_sigframe() */
 227
 228 /*****************************************************************************/
 229 /*
 230  *
 231  */
 232 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
 233 {
 234         struct sigframe __user *frame;
 235         int rsig;
 236
 237         set_fs(USER_DS);
 238
 239         frame = get_sigframe(ka, sizeof(*frame));
 240
 241         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 242                 goto give_sigsegv;
 243
 244         rsig = sig;
 245         if (sig < 32 &&
 246             __current_thread_info->exec_domain &&
 247             __current_thread_info->exec_domain->signal_invmap)
 248                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 249
 250         if (__put_user(rsig, &frame->sig) < 0)
 251                 goto give_sigsegv;
 252
 253         if (setup_sigcontext(&frame->sc, set->sig[0]))
 254                 goto give_sigsegv;
 255
 256         if (_NSIG_WORDS > 1) {
 257                 if (__copy_to_user(frame->extramask, &set->sig[1],
 258                                    sizeof(frame->extramask)))
 259                         goto give_sigsegv;
 260         }
 261
 262         /* Set up to return from userspace.  If provided, use a stub
 263          * already in userspace.  */
 264         if (ka->sa.sa_flags & SA_RESTORER) {
 265                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
 266                         goto give_sigsegv;
 267         }
 268         else {
 269                 /* Set up the following code on the stack:
 270                  *      setlos  #__NR_sigreturn,gr7
 271                  *      tira    gr0,0
 272                  */
 273                 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 274                     __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
 275                     __put_user(0xc0700000, &frame->retcode[1]))
 276                         goto give_sigsegv;
 277
 278                 flush_icache_range((unsigned long) frame->retcode,
 279                                    (unsigned long) (frame->retcode + 2));
 280         }
 281
 282         /* Set up registers for the signal handler */
 283         if (current->personality & FDPIC_FUNCPTRS) {
 284                 struct fdpic_func_descriptor __user *funcptr =
 285                         (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 286                 struct fdpic_func_descriptor desc;
 287                 if (copy_from_user(&desc, funcptr, sizeof(desc)))
 288                         goto give_sigsegv;
 289                 __frame->pc = desc.text;
 290                 __frame->gr15 = desc.GOT;
 291         } else {
 292                 __frame->pc   = (unsigned long) ka->sa.sa_handler;
 293                 __frame->gr15 = 0;
 294         }
 295
 296         __frame->sp   = (unsigned long) frame;
 297         __frame->lr   = (unsigned long) &frame->retcode;
 298         __frame->gr8  = sig;
 299
 300 #if DEBUG_SIG
 301         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 302                sig, current->comm, current->pid, frame, __frame->pc,
 303                frame->pretcode);
 304 #endif
 305
 306         return 0;
 307
 308 give_sigsegv:
 309         force_sigsegv(sig, current);
 310         return -EFAULT;
 311
 312 } /* end setup_frame() */
 313
 314 /*****************************************************************************/
 315 /*
 316  *
 317  */
 318 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 319                           sigset_t *set)
 320 {
 321         struct rt_sigframe __user *frame;
 322         int rsig;
 323
 324         set_fs(USER_DS);
 325
 326         frame = get_sigframe(ka, sizeof(*frame));
 327
 328         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 329                 goto give_sigsegv;
 330
 331         rsig = sig;
 332         if (sig < 32 &&
 333             __current_thread_info->exec_domain &&
 334             __current_thread_info->exec_domain->signal_invmap)
 335                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 336
 337         if (__put_user(rsig,            &frame->sig) ||
 338             __put_user(&frame->info,    &frame->pinfo) ||
 339             __put_user(&frame->uc,      &frame->puc))
 340                 goto give_sigsegv;
 341
 342         if (copy_siginfo_to_user(&frame->info, info))
 343                 goto give_sigsegv;
 344
 345         /* Create the ucontext.  */
 346         if (__put_user(0, &frame->uc.uc_flags) ||
 347             __put_user(NULL, &frame->uc.uc_link) ||
 348             __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 349             __put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) ||
 350             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
 351                 goto give_sigsegv;
 352
 353         if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
 354                 goto give_sigsegv;
 355
 356         if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 357                 goto give_sigsegv;
 358
 359         /* Set up to return from userspace.  If provided, use a stub
 360          * already in userspace.  */
 361         if (ka->sa.sa_flags & SA_RESTORER) {
 362                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 363                         goto give_sigsegv;
 364         }
 365         else {
 366                 /* Set up the following code on the stack:
 367                  *      setlos  #__NR_sigreturn,gr7
 368                  *      tira    gr0,0
 369                  */
 370                 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 371                     __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
 372                     __put_user(0xc0700000, &frame->retcode[1]))
 373                         goto give_sigsegv;
 374
 375                 flush_icache_range((unsigned long) frame->retcode,
 376                                    (unsigned long) (frame->retcode + 2));
 377         }
 378
 379         /* Set up registers for signal handler */
 380         if (current->personality & FDPIC_FUNCPTRS) {
 381                 struct fdpic_func_descriptor __user *funcptr =
 382                         (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 383                 struct fdpic_func_descriptor desc;
 384                 if (copy_from_user(&desc, funcptr, sizeof(desc)))
 385                         goto give_sigsegv;
 386                 __frame->pc = desc.text;
 387                 __frame->gr15 = desc.GOT;
 388         } else {
 389                 __frame->pc   = (unsigned long) ka->sa.sa_handler;
 390                 __frame->gr15 = 0;
 391         }
 392
 393         __frame->sp  = (unsigned long) frame;
 394         __frame->lr  = (unsigned long) &frame->retcode;
 395         __frame->gr8 = sig;
 396         __frame->gr9 = (unsigned long) &frame->info;
 397
 398 #if DEBUG_SIG
 399         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 400                sig, current->comm, current->pid, frame, __frame->pc,
 401                frame->pretcode);
 402 #endif
 403
 404         return 0;
 405
 406 give_sigsegv:
 407         force_sigsegv(sig, current);
 408         return -EFAULT;
 409
 410 } /* end setup_rt_frame() */
 411
 412 /*****************************************************************************/
 413 /*
 414  * OK, we're invoking a handler
 415  */
 416 static void handle_signal(unsigned long sig, siginfo_t *info,
 417                          struct k_sigaction *ka)
 418 {
 419         sigset_t *oldset = sigmask_to_save();
 420         int ret;
 421
 422         /* Are we from a system call? */
 423         if (__frame->syscallno != -1) {
 424                 /* If so, check system call restarting.. */
 425                 switch (__frame->gr8) {
 426                 case -ERESTART_RESTARTBLOCK:
 427                 case -ERESTARTNOHAND:
 428                         __frame->gr8 = -EINTR;
 429                         break;
 430
 431                 case -ERESTARTSYS:
 432                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 433                                 __frame->gr8 = -EINTR;
 434                                 break;
 435                         }
 436
 437                         /* fallthrough */
 438                 case -ERESTARTNOINTR:
 439                         __frame->gr8 = __frame->orig_gr8;
 440                         __frame->pc -= 4;
 441                 }
 442                 __frame->syscallno = -1;
 443         }
 444
 445         /* Set up the stack frame */
 446         if (ka->sa.sa_flags & SA_SIGINFO)
 447                 ret = setup_rt_frame(sig, ka, info, oldset);
 448         else
 449                 ret = setup_frame(sig, ka, oldset);
 450
 451         if (ret)
 452                 return;
 453
 454         signal_delivered(sig, info, ka, __frame,
 455                                  test_thread_flag(TIF_SINGLESTEP));
 456 } /* end handle_signal() */
 457
 458 /*****************************************************************************/
 459 /*
 460  * Note that 'init' is a special process: it doesn't get signals it doesn't
 461  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 462  * mistake.
 463  */
 464 static void do_signal(void)
 465 {
 466         struct k_sigaction ka;
 467         siginfo_t info;
 468         int signr;
 469
 470         signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
 471         if (signr > 0) {
 472                 handle_signal(signr, &info, &ka);
 473                 return;
 474         }
 475
 476         /* Did we come from a system call? */
 477         if (__frame->syscallno != -1) {
 478                 /* Restart the system call - no handlers present */
 479                 switch (__frame->gr8) {
 480                 case -ERESTARTNOHAND:
 481                 case -ERESTARTSYS:
 482                 case -ERESTARTNOINTR:
 483                         __frame->gr8 = __frame->orig_gr8;
 484                         __frame->pc -= 4;
 485                         break;
 486
 487                 case -ERESTART_RESTARTBLOCK:
 488                         __frame->gr7 = __NR_restart_syscall;
 489                         __frame->pc -= 4;
 490                         break;
 491                 }
 492                 __frame->syscallno = -1;
 493         }
 494
 495         /* if there's no signal to deliver, we just put the saved sigmask
 496          * back */
 497         restore_saved_sigmask();
 498 } /* end do_signal() */
 499
 500 /*****************************************************************************/
 501 /*
 502  * notification of userspace execution resumption
 503  * - triggered by the TIF_WORK_MASK flags
 504  */
 505 asmlinkage void do_notify_resume(__u32 thread_info_flags)
 506 {
 507         /* pending single-step? */
 508         if (thread_info_flags & _TIF_SINGLESTEP)
 509                 clear_thread_flag(TIF_SINGLESTEP);
 510
 511         /* deal with pending signal delivery */
 512         if (thread_info_flags & _TIF_SIGPENDING)
 513                 do_signal();
 514
 515         /* deal with notification on about to resume userspace execution */
 516         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 517                 clear_thread_flag(TIF_NOTIFY_RESUME);
 518                 tracehook_notify_resume(__frame);
 519         }
 520
 521 } /* end do_notify_resume() */