arch/h8300/kernel/signal.c

   1 /*
   2  *  linux/arch/h8300/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file COPYING in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 /*
  12  * uClinux H8/300 support by Yoshinori Sato <ysato@users.sourceforge.jp>
  13  *                and David McCullough <davidm@snapgear.com>
  14  *
  15  * Based on
  16  * Linux/m68k by Hamish Macdonald
  17  */
  18
  19 /*
  20  * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
  21  * Atari :-) Current limitation: Only one sigstack can be active at one time.
  22  * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
  23  * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
  24  * signal handlers!
  25  */
  26
  27 #include <linux/sched.h>
  28 #include <linux/mm.h>
  29 #include <linux/kernel.h>
  30 #include <linux/signal.h>
  31 #include <linux/syscalls.h>
  32 #include <linux/errno.h>
  33 #include <linux/wait.h>
  34 #include <linux/ptrace.h>
  35 #include <linux/unistd.h>
  36 #include <linux/stddef.h>
  37 #include <linux/highuid.h>
  38 #include <linux/personality.h>
  39 #include <linux/tty.h>
  40 #include <linux/binfmts.h>
  41 #include <linux/tracehook.h>
  42
  43 #include <asm/setup.h>
  44 #include <asm/uaccess.h>
  45 #include <asm/pgtable.h>
  46 #include <asm/traps.h>
  47 #include <asm/ucontext.h>
  48
  49 /*
  50  * Do a signal return; undo the signal stack.
  51  *
  52  * Keep the return code on the stack quadword aligned!
  53  * That makes the cache flush below easier.
  54  */
  55
  56 struct sigframe
  57 {
  58         long dummy_er0;
  59         long dummy_vector;
  60 #if defined(CONFIG_CPU_H8S)
  61         short dummy_exr;
  62 #endif
  63         long dummy_pc;
  64         char *pretcode;
  65         unsigned char retcode[8];
  66         unsigned long extramask[_NSIG_WORDS-1];
  67         struct sigcontext sc;
  68         int sig;
  69 } __attribute__((aligned(2),packed));
  70
  71 struct rt_sigframe
  72 {
  73         long dummy_er0;
  74         long dummy_vector;
  75 #if defined(CONFIG_CPU_H8S)
  76         short dummy_exr;
  77 #endif
  78         long dummy_pc;
  79         char *pretcode;
  80         struct siginfo *pinfo;
  81         void *puc;
  82         unsigned char retcode[8];
  83         struct siginfo info;
  84         struct ucontext uc;
  85         int sig;
  86 } __attribute__((aligned(2),packed));
  87
  88 static inline int
  89 restore_sigcontext(struct sigcontext *usc, int *pd0)
  90 {
  91         struct pt_regs *regs = current_pt_regs();
  92         int err = 0;
  93         unsigned int ccr;
  94         unsigned int usp;
  95         unsigned int er0;
  96
  97         /* Always make any pending restarted system calls return -EINTR */
  98         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  99
 100 #define COPY(r) err |= __get_user(regs->r, &usc->sc_##r)    /* restore passed registers */
 101         COPY(er1);
 102         COPY(er2);
 103         COPY(er3);
 104         COPY(er5);
 105         COPY(pc);
 106         ccr = regs->ccr & 0x10;
 107         COPY(ccr);
 108 #undef COPY
 109         regs->ccr &= 0xef;
 110         regs->ccr |= ccr;
 111         regs->orig_er0 = -1;            /* disable syscall checks */
 112         err |= __get_user(usp, &usc->sc_usp);
 113         wrusp(usp);
 114
 115         err |= __get_user(er0, &usc->sc_er0);
 116         *pd0 = er0;
 117         return err;
 118 }
 119
 120 asmlinkage int sys_sigreturn(void)
 121 {
 122         unsigned long usp = rdusp();
 123         struct sigframe *frame = (struct sigframe *)(usp - 4);
 124         sigset_t set;
 125         int er0;
 126
 127         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 128                 goto badframe;
 129         if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
 130             (_NSIG_WORDS > 1 &&
 131              __copy_from_user(&set.sig[1], &frame->extramask,
 132                               sizeof(frame->extramask))))
 133                 goto badframe;
 134
 135         set_current_blocked(&set);
 136
 137         if (restore_sigcontext(&frame->sc, &er0))
 138                 goto badframe;
 139         return er0;
 140
 141 badframe:
 142         force_sig(SIGSEGV, current);
 143         return 0;
 144 }
 145
 146 asmlinkage int sys_rt_sigreturn(void)
 147 {
 148         unsigned long usp = rdusp();
 149         struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
 150         sigset_t set;
 151         int er0;
 152
 153         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 154                 goto badframe;
 155         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 156                 goto badframe;
 157
 158         set_current_blocked(&set);
 159
 160         if (restore_sigcontext(&frame->uc.uc_mcontext, &er0))
 161                 goto badframe;
 162
 163         if (restore_altstack(&frame->uc.uc_stack))
 164                 goto badframe;
 165
 166         return er0;
 167
 168 badframe:
 169         force_sig(SIGSEGV, current);
 170         return 0;
 171 }
 172
 173 static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 174                              unsigned long mask)
 175 {
 176         int err = 0;
 177
 178         err |= __put_user(regs->er0, &sc->sc_er0);
 179         err |= __put_user(regs->er1, &sc->sc_er1);
 180         err |= __put_user(regs->er2, &sc->sc_er2);
 181         err |= __put_user(regs->er3, &sc->sc_er3);
 182         err |= __put_user(regs->er4, &sc->sc_er4);
 183         err |= __put_user(regs->er5, &sc->sc_er5);
 184         err |= __put_user(regs->er6, &sc->sc_er6);
 185         err |= __put_user(rdusp(),   &sc->sc_usp);
 186         err |= __put_user(regs->pc,  &sc->sc_pc);
 187         err |= __put_user(regs->ccr, &sc->sc_ccr);
 188         err |= __put_user(mask,      &sc->sc_mask);
 189
 190         return err;
 191 }
 192
 193 static inline void *
 194 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
 195 {
 196         unsigned long usp;
 197
 198         /* Default to using normal stack.  */
 199         usp = rdusp();
 200
 201         /* This is the X/Open sanctioned signal stack switching.  */
 202         if (ka->sa.sa_flags & SA_ONSTACK) {
 203                 if (!sas_ss_flags(usp))
 204                         usp = current->sas_ss_sp + current->sas_ss_size;
 205         }
 206         return (void *)((usp - frame_size) & -8UL);
 207 }
 208
 209 static int setup_frame (int sig, struct k_sigaction *ka,
 210                          sigset_t *set, struct pt_regs *regs)
 211 {
 212         struct sigframe *frame;
 213         int err = 0;
 214         int usig;
 215         unsigned char *ret;
 216
 217         frame = get_sigframe(ka, regs, sizeof(*frame));
 218
 219         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 220                 goto give_sigsegv;
 221
 222         usig = current_thread_info()->exec_domain
 223                 && current_thread_info()->exec_domain->signal_invmap
 224                 && sig < 32
 225                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 226                 : sig;
 227
 228         err |= __put_user(usig, &frame->sig);
 229         if (err)
 230                 goto give_sigsegv;
 231
 232         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 233         if (err)
 234                 goto give_sigsegv;
 235
 236         if (_NSIG_WORDS > 1) {
 237                 err |= copy_to_user(frame->extramask, &set->sig[1],
 238                                     sizeof(frame->extramask));
 239                 if (err)
 240                         goto give_sigsegv;
 241         }
 242
 243         ret = frame->retcode;
 244         if (ka->sa.sa_flags & SA_RESTORER)
 245                 ret = (unsigned char *)(ka->sa.sa_restorer);
 246         else {
 247                 /* sub.l er0,er0; mov.b #__NR_sigreturn,r0l; trapa #0 */
 248                 err |= __put_user(0x1a80f800 + (__NR_sigreturn & 0xff),
 249                                   (unsigned long *)(frame->retcode + 0));
 250                 err |= __put_user(0x5700, (unsigned short *)(frame->retcode + 4));
 251         }
 252
 253         /* Set up to return from userspace.  */
 254         err |= __put_user(ret, &frame->pretcode);
 255
 256         if (err)
 257                 goto give_sigsegv;
 258
 259         /* Set up registers for signal handler */
 260         wrusp ((unsigned long) frame);
 261         regs->pc = (unsigned long) ka->sa.sa_handler;
 262         regs->er0 = (current_thread_info()->exec_domain
 263                            && current_thread_info()->exec_domain->signal_invmap
 264                            && sig < 32
 265                            ? current_thread_info()->exec_domain->signal_invmap[sig]
 266                           : sig);
 267         regs->er1 = (unsigned long)&(frame->sc);
 268         regs->er5 = current->mm->start_data;    /* GOT base */
 269
 270         return 0;
 271
 272 give_sigsegv:
 273         force_sigsegv(sig, current);
 274         return -EFAULT;
 275 }
 276
 277 static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
 278                             sigset_t *set, struct pt_regs *regs)
 279 {
 280         struct rt_sigframe *frame;
 281         int err = 0;
 282         int usig;
 283         unsigned char *ret;
 284
 285         frame = get_sigframe(ka, regs, sizeof(*frame));
 286
 287         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 288                 goto give_sigsegv;
 289
 290         usig = current_thread_info()->exec_domain
 291                 && current_thread_info()->exec_domain->signal_invmap
 292                 && sig < 32
 293                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 294                 : sig;
 295
 296         err |= __put_user(usig, &frame->sig);
 297         if (err)
 298                 goto give_sigsegv;
 299
 300         err |= __put_user(&frame->info, &frame->pinfo);
 301         err |= __put_user(&frame->uc, &frame->puc);
 302         err |= copy_siginfo_to_user(&frame->info, info);
 303         if (err)
 304                 goto give_sigsegv;
 305
 306         /* Create the ucontext.  */
 307         err |= __put_user(0, &frame->uc.uc_flags);
 308         err |= __put_user(0, &frame->uc.uc_link);
 309         err |= __save_altstack(&frame->uc.uc_stack, rdusp());
 310         err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 311         err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));
 312         if (err)
 313                 goto give_sigsegv;
 314
 315         /* Set up to return from userspace.  */
 316         ret = frame->retcode;
 317         if (ka->sa.sa_flags & SA_RESTORER)
 318                 ret = (unsigned char *)(ka->sa.sa_restorer);
 319         else {
 320                 /* sub.l er0,er0; mov.b #__NR_sigreturn,r0l; trapa #0 */
 321                 err |= __put_user(0x1a80f800 + (__NR_sigreturn & 0xff),
 322                                   (unsigned long *)(frame->retcode + 0));
 323                 err |= __put_user(0x5700, (unsigned short *)(frame->retcode + 4));
 324         }
 325         err |= __put_user(ret, &frame->pretcode);
 326
 327         if (err)
 328                 goto give_sigsegv;
 329
 330         /* Set up registers for signal handler */
 331         wrusp ((unsigned long) frame);
 332         regs->pc  = (unsigned long) ka->sa.sa_handler;
 333         regs->er0 = (current_thread_info()->exec_domain
 334                      && current_thread_info()->exec_domain->signal_invmap
 335                      && sig < 32
 336                      ? current_thread_info()->exec_domain->signal_invmap[sig]
 337                      : sig);
 338         regs->er1 = (unsigned long)&(frame->info);
 339         regs->er2 = (unsigned long)&frame->uc;
 340         regs->er5 = current->mm->start_data;    /* GOT base */
 341
 342         return 0;
 343
 344 give_sigsegv:
 345         force_sigsegv(sig, current);
 346         return -EFAULT;
 347 }
 348
 349 /*
 350  * OK, we're invoking a handler
 351  */
 352 static void
 353 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 354               struct pt_regs * regs)
 355 {
 356         sigset_t *oldset = sigmask_to_save();
 357         int ret;
 358         /* are we from a system call? */
 359         if (regs->orig_er0 >= 0) {
 360                 switch (regs->er0) {
 361                         case -ERESTART_RESTARTBLOCK:
 362                         case -ERESTARTNOHAND:
 363                                 regs->er0 = -EINTR;
 364                                 break;
 365
 366                         case -ERESTARTSYS:
 367                                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 368                                         regs->er0 = -EINTR;
 369                                         break;
 370                                 }
 371                         /* fallthrough */
 372                         case -ERESTARTNOINTR:
 373                                 regs->er0 = regs->orig_er0;
 374                                 regs->pc -= 2;
 375                 }
 376         }
 377
 378         /* set up the stack frame */
 379         if (ka->sa.sa_flags & SA_SIGINFO)
 380                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 381         else
 382                 ret = setup_frame(sig, ka, oldset, regs);
 383
 384         if (!ret)
 385                 signal_delivered(sig, info, ka, regs, 0);
 386 }
 387
 388 /*
 389  * Note that 'init' is a special process: it doesn't get signals it doesn't
 390  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 391  * mistake.
 392  */
 393 static void do_signal(struct pt_regs *regs)
 394 {
 395         siginfo_t info;
 396         int signr;
 397         struct k_sigaction ka;
 398
 399         /*
 400          * We want the common case to go fast, which
 401          * is why we may in certain cases get here from
 402          * kernel mode. Just return without doing anything
 403          * if so.
 404          */
 405         if ((regs->ccr & 0x10))
 406                 return;
 407
 408         current->thread.esp0 = (unsigned long) regs;
 409
 410         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 411         if (signr > 0) {
 412                 /* Whee!  Actually deliver the signal.  */
 413                 handle_signal(signr, &info, &ka, regs);
 414                 return;
 415         }
 416         /* Did we come from a system call? */
 417         if (regs->orig_er0 >= 0) {
 418                 /* Restart the system call - no handlers present */
 419                 if (regs->er0 == -ERESTARTNOHAND ||
 420                     regs->er0 == -ERESTARTSYS ||
 421                     regs->er0 == -ERESTARTNOINTR) {
 422                         regs->er0 = regs->orig_er0;
 423                         regs->pc -= 2;
 424                 }
 425                 if (regs->er0 == -ERESTART_RESTARTBLOCK){
 426                         regs->er0 = __NR_restart_syscall;
 427                         regs->pc -= 2;
 428                 }
 429         }
 430
 431         /* If there's no signal to deliver, we just restore the saved mask.  */
 432         restore_saved_sigmask();
 433 }
 434
 435 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 436 {
 437         if (thread_info_flags & _TIF_SIGPENDING)
 438                 do_signal(regs);
 439
 440         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 441                 clear_thread_flag(TIF_NOTIFY_RESUME);
 442                 tracehook_notify_resume(regs);
 443         }
 444 }