arch/v850/kernel/signal.c

   1 /*
   2  * arch/v850/kernel/signal.c -- Signal handling
   3  *
   4  *  Copyright (C) 2001,02,03  NEC Electronics Corporation
   5  *  Copyright (C) 2001,02,03  Miles Bader <miles@gnu.org>
   6  *  Copyright (C) 1999,2000,2002  Niibe Yutaka & Kaz Kojima
   7  *  Copyright (C) 1991,1992  Linus Torvalds
   8  *
   9  * This file is subject to the terms and conditions of the GNU General
  10  * Public License.  See the file COPYING in the main directory of this
  11  * archive for more details.
  12  *
  13  * 1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  14  *
  15  * This file was derived from the sh version, arch/sh/kernel/signal.c
  16  */
  17
  18 #include <linux/mm.h>
  19 #include <linux/smp.h>
  20 #include <linux/smp_lock.h>
  21 #include <linux/kernel.h>
  22 #include <linux/signal.h>
  23 #include <linux/errno.h>
  24 #include <linux/wait.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/unistd.h>
  27 #include <linux/stddef.h>
  28 #include <linux/personality.h>
  29 #include <linux/tty.h>
  30
  31 #include <asm/ucontext.h>
  32 #include <asm/uaccess.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/pgalloc.h>
  35 #include <asm/thread_info.h>
  36 #include <asm/cacheflush.h>
  37
  38 #define DEBUG_SIG 0
  39
  40 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  41
  42 asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
  43
  44 /*
  45  * Atomically swap in the new signal mask, and wait for a signal.
  46  */
  47 asmlinkage int
  48 sys_sigsuspend(old_sigset_t mask, struct pt_regs *regs)
  49 {
  50         sigset_t saveset;
  51
  52         mask &= _BLOCKABLE;
  53         spin_lock_irq(&current->sighand->siglock);
  54         saveset = current->blocked;
  55         siginitset(&current->blocked, mask);
  56         recalc_sigpending();
  57         spin_unlock_irq(&current->sighand->siglock);
  58
  59         regs->gpr[GPR_RVAL] = -EINTR;
  60         while (1) {
  61                 current->state = TASK_INTERRUPTIBLE;
  62                 schedule();
  63                 if (do_signal(regs, &saveset))
  64                         return -EINTR;
  65         }
  66 }
  67
  68 asmlinkage int
  69 sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
  70                   struct pt_regs *regs)
  71 {
  72         sigset_t saveset, newset;
  73
  74         /* XXX: Don't preclude handling different sized sigset_t's.  */
  75         if (sigsetsize != sizeof(sigset_t))
  76                 return -EINVAL;
  77
  78         if (copy_from_user(&newset, unewset, sizeof(newset)))
  79                 return -EFAULT;
  80         sigdelsetmask(&newset, ~_BLOCKABLE);
  81         spin_lock_irq(&current->sighand->siglock);
  82         saveset = current->blocked;
  83         current->blocked = newset;
  84         recalc_sigpending();
  85         spin_unlock_irq(&current->sighand->siglock);
  86
  87         regs->gpr[GPR_RVAL] = -EINTR;
  88         while (1) {
  89                 current->state = TASK_INTERRUPTIBLE;
  90                 schedule();
  91                 if (do_signal(regs, &saveset))
  92                         return -EINTR;
  93         }
  94 }
  95
  96 asmlinkage int
  97 sys_sigaction(int sig, const struct old_sigaction *act,
  98               struct old_sigaction *oact)
  99 {
 100         struct k_sigaction new_ka, old_ka;
 101         int ret;
 102
 103         if (act) {
 104                 old_sigset_t mask;
 105                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 106                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 107                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 108                         return -EFAULT;
 109                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 110                 __get_user(mask, &act->sa_mask);
 111                 siginitset(&new_ka.sa.sa_mask, mask);
 112         }
 113
 114         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 115
 116         if (!ret && oact) {
 117                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 118                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 119                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 120                         return -EFAULT;
 121                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 122                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 123         }
 124
 125         return ret;
 126 }
 127
 128 asmlinkage int
 129 sys_sigaltstack(const stack_t *uss, stack_t *uoss,
 130                 struct pt_regs *regs)
 131 {
 132         return do_sigaltstack(uss, uoss, regs->gpr[GPR_SP]);
 133 }
 134
 135
 136 /*
 137  * Do a signal return; undo the signal stack.
 138  */
 139
 140 struct sigframe
 141 {
 142         struct sigcontext sc;
 143         unsigned long extramask[_NSIG_WORDS-1];
 144         unsigned long tramp[2]; /* signal trampoline */
 145 };
 146
 147 struct rt_sigframe
 148 {
 149         struct siginfo info;
 150         struct ucontext uc;
 151         unsigned long tramp[2]; /* signal trampoline */
 152 };
 153
 154 static int
 155 restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *rval_p)
 156 {
 157         unsigned int err = 0;
 158
 159 #define COPY(x)         err |= __get_user(regs->x, &sc->regs.x)
 160         COPY(gpr[0]);   COPY(gpr[1]);   COPY(gpr[2]);   COPY(gpr[3]);
 161         COPY(gpr[4]);   COPY(gpr[5]);   COPY(gpr[6]);   COPY(gpr[7]);
 162         COPY(gpr[8]);   COPY(gpr[9]);   COPY(gpr[10]);  COPY(gpr[11]);
 163         COPY(gpr[12]);  COPY(gpr[13]);  COPY(gpr[14]);  COPY(gpr[15]);
 164         COPY(gpr[16]);  COPY(gpr[17]);  COPY(gpr[18]);  COPY(gpr[19]);
 165         COPY(gpr[20]);  COPY(gpr[21]);  COPY(gpr[22]);  COPY(gpr[23]);
 166         COPY(gpr[24]);  COPY(gpr[25]);  COPY(gpr[26]);  COPY(gpr[27]);
 167         COPY(gpr[28]);  COPY(gpr[29]);  COPY(gpr[30]);  COPY(gpr[31]);
 168         COPY(pc);       COPY(psw);
 169         COPY(ctpc);     COPY(ctpsw);    COPY(ctbp);
 170 #undef COPY
 171
 172         return err;
 173 }
 174
 175 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 176 {
 177         struct sigframe *frame = (struct sigframe *)regs->gpr[GPR_SP];
 178         sigset_t set;
 179         int rval;
 180
 181         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 182                 goto badframe;
 183
 184         if (__get_user(set.sig[0], &frame->sc.oldmask)
 185             || (_NSIG_WORDS > 1
 186                 && __copy_from_user(&set.sig[1], &frame->extramask,
 187                                     sizeof(frame->extramask))))
 188                 goto badframe;
 189
 190         sigdelsetmask(&set, ~_BLOCKABLE);
 191         spin_lock_irq(&current->sighand->siglock);
 192         current->blocked = set;
 193         recalc_sigpending();
 194         spin_unlock_irq(&current->sighand->siglock);
 195
 196         if (restore_sigcontext(regs, &frame->sc, &rval))
 197                 goto badframe;
 198         return rval;
 199
 200 badframe:
 201         force_sig(SIGSEGV, current);
 202         return 0;
 203 }
 204
 205 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 206 {
 207         struct rt_sigframe *frame = (struct rt_sigframe *)regs->gpr[GPR_SP];
 208         sigset_t set;
 209         stack_t st;
 210         int rval;
 211
 212         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 213                 goto badframe;
 214
 215         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 216                 goto badframe;
 217
 218         sigdelsetmask(&set, ~_BLOCKABLE);
 219         spin_lock_irq(&current->sighand->siglock);
 220         current->blocked = set;
 221         recalc_sigpending();
 222         spin_unlock_irq(&current->sighand->siglock);
 223
 224         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
 225                 goto badframe;
 226
 227         if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
 228                 goto badframe;
 229         /* It is more difficult to avoid calling this function than to
 230            call it and ignore errors.  */
 231         do_sigaltstack(&st, NULL, regs->gpr[GPR_SP]);
 232
 233         return rval;
 234
 235 badframe:
 236         force_sig(SIGSEGV, current);
 237         return 0;
 238 }
 239
 240 /*
 241  * Set up a signal frame.
 242  */
 243
 244 static int
 245 setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
 246                  unsigned long mask)
 247 {
 248         int err = 0;
 249
 250 #define COPY(x)         err |= __put_user(regs->x, &sc->regs.x)
 251         COPY(gpr[0]);   COPY(gpr[1]);   COPY(gpr[2]);   COPY(gpr[3]);
 252         COPY(gpr[4]);   COPY(gpr[5]);   COPY(gpr[6]);   COPY(gpr[7]);
 253         COPY(gpr[8]);   COPY(gpr[9]);   COPY(gpr[10]);  COPY(gpr[11]);
 254         COPY(gpr[12]);  COPY(gpr[13]);  COPY(gpr[14]);  COPY(gpr[15]);
 255         COPY(gpr[16]);  COPY(gpr[17]);  COPY(gpr[18]);  COPY(gpr[19]);
 256         COPY(gpr[20]);  COPY(gpr[21]);  COPY(gpr[22]);  COPY(gpr[23]);
 257         COPY(gpr[24]);  COPY(gpr[25]);  COPY(gpr[26]);  COPY(gpr[27]);
 258         COPY(gpr[28]);  COPY(gpr[29]);  COPY(gpr[30]);  COPY(gpr[31]);
 259         COPY(pc);       COPY(psw);
 260         COPY(ctpc);     COPY(ctpsw);    COPY(ctbp);
 261 #undef COPY
 262
 263         err |= __put_user(mask, &sc->oldmask);
 264
 265         return err;
 266 }
 267
 268 /*
 269  * Determine which stack to use..
 270  */
 271 static inline void *
 272 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
 273 {
 274         /* Default to using normal stack */
 275         unsigned long sp = regs->gpr[GPR_SP];
 276
 277         if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
 278                 sp = current->sas_ss_sp + current->sas_ss_size;
 279
 280         return (void *)((sp - frame_size) & -8UL);
 281 }
 282
 283 static void setup_frame(int sig, struct k_sigaction *ka,
 284                         sigset_t *set, struct pt_regs *regs)
 285 {
 286         struct sigframe *frame;
 287         int err = 0;
 288         int signal;
 289
 290         frame = get_sigframe(ka, regs, sizeof(*frame));
 291
 292         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 293                 goto give_sigsegv;
 294
 295         signal = current_thread_info()->exec_domain
 296                 && current_thread_info()->exec_domain->signal_invmap
 297                 && sig < 32
 298                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 299                 : sig;
 300
 301         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 302
 303         if (_NSIG_WORDS > 1) {
 304                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 305                                       sizeof(frame->extramask));
 306         }
 307
 308         /* Set up to return from userspace.  If provided, use a stub
 309            already in userspace.  */
 310         if (ka->sa.sa_flags & SA_RESTORER) {
 311                 regs->gpr[GPR_LP] = (unsigned long) ka->sa.sa_restorer;
 312         } else {
 313                 /* Note, these encodings are _little endian_!  */
 314
 315                 /* addi  __NR_sigreturn, r0, r12  */
 316                 err |= __put_user(0x6600 | (__NR_sigreturn << 16),
 317                                   frame->tramp + 0);
 318                 /* trap 0 */
 319                 err |= __put_user(0x010007e0,
 320                                   frame->tramp + 1);
 321
 322                 regs->gpr[GPR_LP] = (unsigned long)frame->tramp;
 323
 324                 flush_cache_sigtramp (regs->gpr[GPR_LP]);
 325         }
 326
 327         if (err)
 328                 goto give_sigsegv;
 329
 330         /* Set up registers for signal handler.  */
 331         regs->pc = (v850_reg_t) ka->sa.sa_handler;
 332         regs->gpr[GPR_SP] = (v850_reg_t)frame;
 333         /* Signal handler args:  */
 334         regs->gpr[GPR_ARG0] = signal; /* arg 0: signum */
 335         regs->gpr[GPR_ARG1] = (v850_reg_t)&frame->sc;/* arg 1: sigcontext */
 336
 337         set_fs(USER_DS);
 338
 339 #if DEBUG_SIG
 340         printk("SIG deliver (%s:%d): sp=%p pc=%08lx ra=%08lx\n",
 341                 current->comm, current->pid, frame, regs->pc, );
 342 #endif
 343
 344         return;
 345
 346 give_sigsegv:
 347         force_sigsegv(sig, current);
 348 }
 349
 350 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 351                            sigset_t *set, struct pt_regs *regs)
 352 {
 353         struct rt_sigframe *frame;
 354         int err = 0;
 355         int signal;
 356
 357         frame = get_sigframe(ka, regs, sizeof(*frame));
 358
 359         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 360                 goto give_sigsegv;
 361
 362         signal = current_thread_info()->exec_domain
 363                 && current_thread_info()->exec_domain->signal_invmap
 364                 && sig < 32
 365                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 366                 : sig;
 367
 368         err |= copy_siginfo_to_user(&frame->info, info);
 369
 370         /* Create the ucontext.  */
 371         err |= __put_user(0, &frame->uc.uc_flags);
 372         err |= __put_user(0, &frame->uc.uc_link);
 373         err |= __put_user((void *)current->sas_ss_sp,
 374                           &frame->uc.uc_stack.ss_sp);
 375         err |= __put_user(sas_ss_flags(regs->gpr[GPR_SP]),
 376                           &frame->uc.uc_stack.ss_flags);
 377         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 378         err |= setup_sigcontext(&frame->uc.uc_mcontext,
 379                                 regs, set->sig[0]);
 380         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 381
 382         /* Set up to return from userspace.  If provided, use a stub
 383            already in userspace.  */
 384         if (ka->sa.sa_flags & SA_RESTORER) {
 385                 regs->gpr[GPR_LP] = (unsigned long) ka->sa.sa_restorer;
 386         } else {
 387                 /* Note, these encodings are _little endian_!  */
 388
 389                 /* addi  __NR_sigreturn, r0, r12  */
 390                 err |= __put_user(0x6600 | (__NR_sigreturn << 16),
 391                                   frame->tramp + 0);
 392                 /* trap 0 */
 393                 err |= __put_user(0x010007e0,
 394                                   frame->tramp + 1);
 395
 396                 regs->gpr[GPR_LP] = (unsigned long)frame->tramp;
 397
 398                 flush_cache_sigtramp (regs->gpr[GPR_LP]);
 399         }
 400
 401         if (err)
 402                 goto give_sigsegv;
 403
 404         /* Set up registers for signal handler.  */
 405         regs->pc = (v850_reg_t) ka->sa.sa_handler;
 406         regs->gpr[GPR_SP] = (v850_reg_t)frame;
 407         /* Signal handler args:  */
 408         regs->gpr[GPR_ARG0] = signal; /* arg 0: signum */
 409         regs->gpr[GPR_ARG1] = (v850_reg_t)&frame->info; /* arg 1: siginfo */
 410         regs->gpr[GPR_ARG2] = (v850_reg_t)&frame->uc; /* arg 2: ucontext */
 411
 412         set_fs(USER_DS);
 413
 414 #if DEBUG_SIG
 415         printk("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 416                 current->comm, current->pid, frame, regs->pc, regs->pr);
 417 #endif
 418
 419         return;
 420
 421 give_sigsegv:
 422         force_sigsegv(sig, current);
 423 }
 424
 425 /*
 426  * OK, we're invoking a handler
 427  */
 428
 429 static void
 430 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 431               sigset_t *oldset, struct pt_regs * regs)
 432 {
 433         /* Are we from a system call? */
 434         if (PT_REGS_SYSCALL (regs)) {
 435                 /* If so, check system call restarting.. */
 436                 switch (regs->gpr[GPR_RVAL]) {
 437                 case -ERESTART_RESTARTBLOCK:
 438                         current_thread_info()->restart_block.fn =
 439                                 do_no_restart_syscall;
 440                         /* fall through */
 441                 case -ERESTARTNOHAND:
 442                         regs->gpr[GPR_RVAL] = -EINTR;
 443                         break;
 444
 445                 case -ERESTARTSYS:
 446                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 447                                 regs->gpr[GPR_RVAL] = -EINTR;
 448                                 break;
 449                         }
 450                         /* fallthrough */
 451                 case -ERESTARTNOINTR:
 452                         regs->gpr[12] = PT_REGS_SYSCALL (regs);
 453                         regs->pc -= 4; /* Size of `trap 0' insn.  */
 454                 }
 455
 456                 PT_REGS_SET_SYSCALL (regs, 0);
 457         }
 458
 459         /* Set up the stack frame */
 460         if (ka->sa.sa_flags & SA_SIGINFO)
 461                 setup_rt_frame(sig, ka, info, oldset, regs);
 462         else
 463                 setup_frame(sig, ka, oldset, regs);
 464
 465         spin_lock_irq(&current->sighand->siglock);
 466         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 467         if (!(ka->sa.sa_flags & SA_NODEFER))
 468                 sigaddset(&current->blocked,sig);
 469         recalc_sigpending();
 470         spin_unlock_irq(&current->sighand->siglock);
 471 }
 472
 473 /*
 474  * Note that 'init' is a special process: it doesn't get signals it doesn't
 475  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 476  * mistake.
 477  *
 478  * Note that we go through the signals twice: once to check the signals that
 479  * the kernel can handle, and then we build all the user-level signal handling
 480  * stack-frames in one go after that.
 481  */
 482 int do_signal(struct pt_regs *regs, sigset_t *oldset)
 483 {
 484         siginfo_t info;
 485         int signr;
 486         struct k_sigaction ka;
 487
 488         /*
 489          * We want the common case to go fast, which
 490          * is why we may in certain cases get here from
 491          * kernel mode. Just return without doing anything
 492          * if so.
 493          */
 494         if (!user_mode(regs))
 495                 return 1;
 496
 497         if (!oldset)
 498                 oldset = &current->blocked;
 499
 500         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 501         if (signr > 0) {
 502                 /* Whee!  Actually deliver the signal.  */
 503                 handle_signal(signr, &info, &ka, oldset, regs);
 504                 return 1;
 505         }
 506
 507         /* Did we come from a system call? */
 508         if (PT_REGS_SYSCALL (regs)) {
 509                 int rval = (int)regs->gpr[GPR_RVAL];
 510                 /* Restart the system call - no handlers present */
 511                 if (rval == -ERESTARTNOHAND
 512                     || rval == -ERESTARTSYS
 513                     || rval == -ERESTARTNOINTR)
 514                 {
 515                         regs->gpr[12] = PT_REGS_SYSCALL (regs);
 516                         regs->pc -= 4; /* Size of `trap 0' insn.  */
 517                 }
 518                 else if (rval == -ERESTART_RESTARTBLOCK) {
 519                         regs->gpr[12] = __NR_restart_syscall;
 520                         regs->pc -= 4; /* Size of `trap 0' insn.  */
 521                 }
 522         }
 523         return 0;
 524 }