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