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