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/freezer.h>
  24 #include <linux/tracehook.h>
  25 #include <asm/ucontext.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/cacheflush.h>
  28
  29 #define DEBUG_SIG 0
  30
  31 struct fdpic_func_descriptor {
  32         unsigned long   text;
  33         unsigned long   GOT;
  34 };
  35
  36 /*
  37  * Atomically swap in the new signal mask, and wait for a signal.
  38  */
  39 asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  40 {
  41         sigset_t blocked;
  42         siginitset(&blocked, mask);
  43         return sigsuspend(&blocked);
  44 }
  45
  46 asmlinkage int sys_sigaction(int sig,
  47                              const struct old_sigaction __user *act,
  48                              struct old_sigaction __user *oact)
  49 {
  50         struct k_sigaction new_ka, old_ka;
  51         int ret;
  52
  53         if (act) {
  54                 old_sigset_t mask;
  55                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  56                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  57                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
  58                     __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
  59                     __get_user(mask, &act->sa_mask))
  60                         return -EFAULT;
  61                 siginitset(&new_ka.sa.sa_mask, mask);
  62         }
  63
  64         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  65
  66         if (!ret && oact) {
  67                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  68                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  69                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
  70                     __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
  71                     __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
  72                         return -EFAULT;
  73         }
  74
  75         return ret;
  76 }
  77
  78 asmlinkage
  79 int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
  80 {
  81         return do_sigaltstack(uss, uoss, __frame->sp);
  82 }
  83
  84
  85 /*
  86  * Do a signal return; undo the signal stack.
  87  */
  88
  89 struct sigframe
  90 {
  91         __sigrestore_t pretcode;
  92         int sig;
  93         struct sigcontext sc;
  94         unsigned long extramask[_NSIG_WORDS-1];
  95         uint32_t retcode[2];
  96 };
  97
  98 struct rt_sigframe
  99 {
 100         __sigrestore_t pretcode;
 101         int sig;
 102         struct siginfo __user *pinfo;
 103         void __user *puc;
 104         struct siginfo info;
 105         struct ucontext uc;
 106         uint32_t retcode[2];
 107 };
 108
 109 static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
 110 {
 111         struct user_context *user = current->thread.user;
 112         unsigned long tbr, psr;
 113
 114         /* Always make any pending restarted system calls return -EINTR */
 115         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 116
 117         tbr = user->i.tbr;
 118         psr = user->i.psr;
 119         if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
 120                 goto badframe;
 121         user->i.tbr = tbr;
 122         user->i.psr = psr;
 123
 124         restore_user_regs(user);
 125
 126         user->i.syscallno = -1;         /* disable syscall checks */
 127
 128         *_gr8 = user->i.gr[8];
 129         return 0;
 130
 131  badframe:
 132         return 1;
 133 }
 134
 135 asmlinkage int sys_sigreturn(void)
 136 {
 137         struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
 138         sigset_t set;
 139         int gr8;
 140
 141         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 142                 goto badframe;
 143         if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
 144                 goto badframe;
 145
 146         if (_NSIG_WORDS > 1 &&
 147             __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
 148                 goto badframe;
 149
 150         set_current_blocked(&set);
 151
 152         if (restore_sigcontext(&frame->sc, &gr8))
 153                 goto badframe;
 154         return gr8;
 155
 156  badframe:
 157         force_sig(SIGSEGV, current);
 158         return 0;
 159 }
 160
 161 asmlinkage int sys_rt_sigreturn(void)
 162 {
 163         struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
 164         sigset_t set;
 165         int gr8;
 166
 167         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 168                 goto badframe;
 169         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 170                 goto badframe;
 171
 172         set_current_blocked(&set);
 173
 174         if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
 175                 goto badframe;
 176
 177         if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
 178                 goto badframe;
 179
 180         return gr8;
 181
 182 badframe:
 183         force_sig(SIGSEGV, current);
 184         return 0;
 185 }
 186
 187 /*
 188  * Set up a signal frame
 189  */
 190 static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
 191 {
 192         save_user_regs(current->thread.user);
 193
 194         if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
 195                 goto badframe;
 196
 197         /* non-iBCS2 extensions.. */
 198         if (__put_user(mask, &sc->sc_oldmask) < 0)
 199                 goto badframe;
 200
 201         return 0;
 202
 203  badframe:
 204         return 1;
 205 }
 206
 207 /*****************************************************************************/
 208 /*
 209  * Determine which stack to use..
 210  */
 211 static inline void __user *get_sigframe(struct k_sigaction *ka,
 212                                         size_t frame_size)
 213 {
 214         unsigned long sp;
 215
 216         /* Default to using normal stack */
 217         sp = __frame->sp;
 218
 219         /* This is the X/Open sanctioned signal stack switching.  */
 220         if (ka->sa.sa_flags & SA_ONSTACK) {
 221                 if (! sas_ss_flags(sp))
 222                         sp = current->sas_ss_sp + current->sas_ss_size;
 223         }
 224
 225         return (void __user *) ((sp - frame_size) & ~7UL);
 226
 227 } /* end get_sigframe() */
 228
 229 /*****************************************************************************/
 230 /*
 231  *
 232  */
 233 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
 234 {
 235         struct sigframe __user *frame;
 236         int rsig;
 237
 238         set_fs(USER_DS);
 239
 240         frame = get_sigframe(ka, sizeof(*frame));
 241
 242         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 243                 goto give_sigsegv;
 244
 245         rsig = sig;
 246         if (sig < 32 &&
 247             __current_thread_info->exec_domain &&
 248             __current_thread_info->exec_domain->signal_invmap)
 249                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 250
 251         if (__put_user(rsig, &frame->sig) < 0)
 252                 goto give_sigsegv;
 253
 254         if (setup_sigcontext(&frame->sc, set->sig[0]))
 255                 goto give_sigsegv;
 256
 257         if (_NSIG_WORDS > 1) {
 258                 if (__copy_to_user(frame->extramask, &set->sig[1],
 259                                    sizeof(frame->extramask)))
 260                         goto give_sigsegv;
 261         }
 262
 263         /* Set up to return from userspace.  If provided, use a stub
 264          * already in userspace.  */
 265         if (ka->sa.sa_flags & SA_RESTORER) {
 266                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
 267                         goto give_sigsegv;
 268         }
 269         else {
 270                 /* Set up the following code on the stack:
 271                  *      setlos  #__NR_sigreturn,gr7
 272                  *      tira    gr0,0
 273                  */
 274                 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 275                     __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
 276                     __put_user(0xc0700000, &frame->retcode[1]))
 277                         goto give_sigsegv;
 278
 279                 flush_icache_range((unsigned long) frame->retcode,
 280                                    (unsigned long) (frame->retcode + 2));
 281         }
 282
 283         /* Set up registers for the signal handler */
 284         if (current->personality & FDPIC_FUNCPTRS) {
 285                 struct fdpic_func_descriptor __user *funcptr =
 286                         (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 287                 struct fdpic_func_descriptor desc;
 288                 if (copy_from_user(&desc, funcptr, sizeof(desc)))
 289                         goto give_sigsegv;
 290                 __frame->pc = desc.text;
 291                 __frame->gr15 = desc.GOT;
 292         } else {
 293                 __frame->pc   = (unsigned long) ka->sa.sa_handler;
 294                 __frame->gr15 = 0;
 295         }
 296
 297         __frame->sp   = (unsigned long) frame;
 298         __frame->lr   = (unsigned long) &frame->retcode;
 299         __frame->gr8  = sig;
 300
 301         /* the tracer may want to single-step inside the handler */
 302         if (test_thread_flag(TIF_SINGLESTEP))
 303                 ptrace_notify(SIGTRAP);
 304
 305 #if DEBUG_SIG
 306         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 307                sig, current->comm, current->pid, frame, __frame->pc,
 308                frame->pretcode);
 309 #endif
 310
 311         return 0;
 312
 313 give_sigsegv:
 314         force_sigsegv(sig, current);
 315         return -EFAULT;
 316
 317 } /* end setup_frame() */
 318
 319 /*****************************************************************************/
 320 /*
 321  *
 322  */
 323 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 324                           sigset_t *set)
 325 {
 326         struct rt_sigframe __user *frame;
 327         int rsig;
 328
 329         set_fs(USER_DS);
 330
 331         frame = get_sigframe(ka, sizeof(*frame));
 332
 333         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 334                 goto give_sigsegv;
 335
 336         rsig = sig;
 337         if (sig < 32 &&
 338             __current_thread_info->exec_domain &&
 339             __current_thread_info->exec_domain->signal_invmap)
 340                 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
 341
 342         if (__put_user(rsig,            &frame->sig) ||
 343             __put_user(&frame->info,    &frame->pinfo) ||
 344             __put_user(&frame->uc,      &frame->puc))
 345                 goto give_sigsegv;
 346
 347         if (copy_siginfo_to_user(&frame->info, info))
 348                 goto give_sigsegv;
 349
 350         /* Create the ucontext.  */
 351         if (__put_user(0, &frame->uc.uc_flags) ||
 352             __put_user(NULL, &frame->uc.uc_link) ||
 353             __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
 354             __put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) ||
 355             __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
 356                 goto give_sigsegv;
 357
 358         if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
 359                 goto give_sigsegv;
 360
 361         if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 362                 goto give_sigsegv;
 363
 364         /* Set up to return from userspace.  If provided, use a stub
 365          * already in userspace.  */
 366         if (ka->sa.sa_flags & SA_RESTORER) {
 367                 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
 368                         goto give_sigsegv;
 369         }
 370         else {
 371                 /* Set up the following code on the stack:
 372                  *      setlos  #__NR_sigreturn,gr7
 373                  *      tira    gr0,0
 374                  */
 375                 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 376                     __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
 377                     __put_user(0xc0700000, &frame->retcode[1]))
 378                         goto give_sigsegv;
 379
 380                 flush_icache_range((unsigned long) frame->retcode,
 381                                    (unsigned long) (frame->retcode + 2));
 382         }
 383
 384         /* Set up registers for signal handler */
 385         if (current->personality & FDPIC_FUNCPTRS) {
 386                 struct fdpic_func_descriptor __user *funcptr =
 387                         (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
 388                 struct fdpic_func_descriptor desc;
 389                 if (copy_from_user(&desc, funcptr, sizeof(desc)))
 390                         goto give_sigsegv;
 391                 __frame->pc = desc.text;
 392                 __frame->gr15 = desc.GOT;
 393         } else {
 394                 __frame->pc   = (unsigned long) ka->sa.sa_handler;
 395                 __frame->gr15 = 0;
 396         }
 397
 398         __frame->sp  = (unsigned long) frame;
 399         __frame->lr  = (unsigned long) &frame->retcode;
 400         __frame->gr8 = sig;
 401         __frame->gr9 = (unsigned long) &frame->info;
 402
 403         /* the tracer may want to single-step inside the handler */
 404         if (test_thread_flag(TIF_SINGLESTEP))
 405                 ptrace_notify(SIGTRAP);
 406
 407 #if DEBUG_SIG
 408         printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 409                sig, current->comm, current->pid, frame, __frame->pc,
 410                frame->pretcode);
 411 #endif
 412
 413         return 0;
 414
 415 give_sigsegv:
 416         force_sigsegv(sig, current);
 417         return -EFAULT;
 418
 419 } /* end setup_rt_frame() */
 420
 421 /*****************************************************************************/
 422 /*
 423  * OK, we're invoking a handler
 424  */
 425 static void handle_signal(unsigned long sig, siginfo_t *info,
 426                          struct k_sigaction *ka)
 427 {
 428         sigset_t *oldset = sigmask_to_save();
 429         int ret;
 430
 431         /* Are we from a system call? */
 432         if (__frame->syscallno != -1) {
 433                 /* If so, check system call restarting.. */
 434                 switch (__frame->gr8) {
 435                 case -ERESTART_RESTARTBLOCK:
 436                 case -ERESTARTNOHAND:
 437                         __frame->gr8 = -EINTR;
 438                         break;
 439
 440                 case -ERESTARTSYS:
 441                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 442                                 __frame->gr8 = -EINTR;
 443                                 break;
 444                         }
 445
 446                         /* fallthrough */
 447                 case -ERESTARTNOINTR:
 448                         __frame->gr8 = __frame->orig_gr8;
 449                         __frame->pc -= 4;
 450                 }
 451                 __frame->syscallno = -1;
 452         }
 453
 454         /* Set up the stack frame */
 455         if (ka->sa.sa_flags & SA_SIGINFO)
 456                 ret = setup_rt_frame(sig, ka, info, oldset);
 457         else
 458                 ret = setup_frame(sig, ka, oldset);
 459
 460         if (ret)
 461                 return;
 462
 463         signal_delivered(sig, info, ka, __frame,
 464                                  test_thread_flag(TIF_SINGLESTEP));
 465 } /* end handle_signal() */
 466
 467 /*****************************************************************************/
 468 /*
 469  * Note that 'init' is a special process: it doesn't get signals it doesn't
 470  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 471  * mistake.
 472  */
 473 static void do_signal(void)
 474 {
 475         struct k_sigaction ka;
 476         siginfo_t info;
 477         int signr;
 478
 479         signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
 480         if (signr > 0) {
 481                 handle_signal(signr, &info, &ka);
 482                 return;
 483         }
 484
 485         /* Did we come from a system call? */
 486         if (__frame->syscallno != -1) {
 487                 /* Restart the system call - no handlers present */
 488                 switch (__frame->gr8) {
 489                 case -ERESTARTNOHAND:
 490                 case -ERESTARTSYS:
 491                 case -ERESTARTNOINTR:
 492                         __frame->gr8 = __frame->orig_gr8;
 493                         __frame->pc -= 4;
 494                         break;
 495
 496                 case -ERESTART_RESTARTBLOCK:
 497                         __frame->gr7 = __NR_restart_syscall;
 498                         __frame->pc -= 4;
 499                         break;
 500                 }
 501                 __frame->syscallno = -1;
 502         }
 503
 504         /* if there's no signal to deliver, we just put the saved sigmask
 505          * back */
 506         restore_saved_sigmask();
 507 } /* end do_signal() */
 508
 509 /*****************************************************************************/
 510 /*
 511  * notification of userspace execution resumption
 512  * - triggered by the TIF_WORK_MASK flags
 513  */
 514 asmlinkage void do_notify_resume(__u32 thread_info_flags)
 515 {
 516         /* pending single-step? */
 517         if (thread_info_flags & _TIF_SINGLESTEP)
 518                 clear_thread_flag(TIF_SINGLESTEP);
 519
 520         /* deal with pending signal delivery */
 521         if (thread_info_flags & _TIF_SIGPENDING)
 522                 do_signal();
 523
 524         /* deal with notification on about to resume userspace execution */
 525         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 526                 clear_thread_flag(TIF_NOTIFY_RESUME);
 527                 tracehook_notify_resume(__frame);
 528         }
 529
 530 } /* end do_notify_resume() */