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->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 ksignal *ksig,
 162                                        size_t frame_size)
 163{
 164        unsigned long sp = sigsp(__frame->sp, ksig);
 165
 166        return (void __user *) ((sp - frame_size) & ~7UL);
 167
 168} /* end get_sigframe() */
 169
 170/*****************************************************************************/
 171/*
 172 *
 173 */
 174static int setup_frame(struct ksignal *ksig, sigset_t *set)
 175{
 176        struct sigframe __user *frame;
 177        int sig = ksig->sig;
 178
 179        frame = get_sigframe(ksig, sizeof(*frame));
 180
 181        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 182                return -EFAULT;
 183
 184        if (__put_user(sig, &frame->sig) < 0)
 185                return -EFAULT;
 186
 187        if (setup_sigcontext(&frame->sc, set->sig[0]))
 188                return -EFAULT;
 189
 190        if (_NSIG_WORDS > 1) {
 191                if (__copy_to_user(frame->extramask, &set->sig[1],
 192                                   sizeof(frame->extramask)))
 193                        return -EFAULT;
 194        }
 195
 196        /* Set up to return from userspace.  If provided, use a stub
 197         * already in userspace.  */
 198        if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 199                if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode) < 0)
 200                        return -EFAULT;
 201        }
 202        else {
 203                /* Set up the following code on the stack:
 204                 *      setlos  #__NR_sigreturn,gr7
 205                 *      tira    gr0,0
 206                 */
 207                if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 208                    __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
 209                    __put_user(0xc0700000, &frame->retcode[1]))
 210                        return -EFAULT;
 211
 212                flush_icache_range((unsigned long) frame->retcode,
 213                                   (unsigned long) (frame->retcode + 2));
 214        }
 215
 216        /* Set up registers for the signal handler */
 217        if (current->personality & FDPIC_FUNCPTRS) {
 218                struct fdpic_func_descriptor __user *funcptr =
 219                        (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
 220                struct fdpic_func_descriptor desc;
 221                if (copy_from_user(&desc, funcptr, sizeof(desc)))
 222                        return -EFAULT;
 223                __frame->pc = desc.text;
 224                __frame->gr15 = desc.GOT;
 225        } else {
 226                __frame->pc   = (unsigned long) ksig->ka.sa.sa_handler;
 227                __frame->gr15 = 0;
 228        }
 229
 230        __frame->sp   = (unsigned long) frame;
 231        __frame->lr   = (unsigned long) &frame->retcode;
 232        __frame->gr8  = sig;
 233
 234#if DEBUG_SIG
 235        printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 236               sig, current->comm, current->pid, frame, __frame->pc,
 237               frame->pretcode);
 238#endif
 239
 240        return 0;
 241} /* end setup_frame() */
 242
 243/*****************************************************************************/
 244/*
 245 *
 246 */
 247static int setup_rt_frame(struct ksignal *ksig, sigset_t *set)
 248{
 249        struct rt_sigframe __user *frame;
 250        int sig = ksig->sig;
 251
 252        frame = get_sigframe(ksig, sizeof(*frame));
 253
 254        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 255                return -EFAULT;
 256
 257        if (__put_user(sig,             &frame->sig) ||
 258            __put_user(&frame->info,    &frame->pinfo) ||
 259            __put_user(&frame->uc,      &frame->puc))
 260                return -EFAULT;
 261
 262        if (copy_siginfo_to_user(&frame->info, &ksig->info))
 263                return -EFAULT;
 264
 265        /* Create the ucontext.  */
 266        if (__put_user(0, &frame->uc.uc_flags) ||
 267            __put_user(NULL, &frame->uc.uc_link) ||
 268            __save_altstack(&frame->uc.uc_stack, __frame->sp))
 269                return -EFAULT;
 270
 271        if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
 272                return -EFAULT;
 273
 274        if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
 275                return -EFAULT;
 276
 277        /* Set up to return from userspace.  If provided, use a stub
 278         * already in userspace.  */
 279        if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 280                if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
 281                        return -EFAULT;
 282        }
 283        else {
 284                /* Set up the following code on the stack:
 285                 *      setlos  #__NR_sigreturn,gr7
 286                 *      tira    gr0,0
 287                 */
 288                if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
 289                    __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
 290                    __put_user(0xc0700000, &frame->retcode[1]))
 291                        return -EFAULT;
 292
 293                flush_icache_range((unsigned long) frame->retcode,
 294                                   (unsigned long) (frame->retcode + 2));
 295        }
 296
 297        /* Set up registers for signal handler */
 298        if (current->personality & FDPIC_FUNCPTRS) {
 299                struct fdpic_func_descriptor __user *funcptr =
 300                        (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
 301                struct fdpic_func_descriptor desc;
 302                if (copy_from_user(&desc, funcptr, sizeof(desc)))
 303                        return -EFAULT;
 304                __frame->pc = desc.text;
 305                __frame->gr15 = desc.GOT;
 306        } else {
 307                __frame->pc   = (unsigned long) ksig->ka.sa.sa_handler;
 308                __frame->gr15 = 0;
 309        }
 310
 311        __frame->sp  = (unsigned long) frame;
 312        __frame->lr  = (unsigned long) &frame->retcode;
 313        __frame->gr8 = sig;
 314        __frame->gr9 = (unsigned long) &frame->info;
 315
 316#if DEBUG_SIG
 317        printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
 318               sig, current->comm, current->pid, frame, __frame->pc,
 319               frame->pretcode);
 320#endif
 321        return 0;
 322
 323} /* end setup_rt_frame() */
 324
 325/*****************************************************************************/
 326/*
 327 * OK, we're invoking a handler
 328 */
 329static void handle_signal(struct ksignal *ksig)
 330{
 331        sigset_t *oldset = sigmask_to_save();
 332        int ret;
 333
 334        /* Are we from a system call? */
 335        if (__frame->syscallno != -1) {
 336                /* If so, check system call restarting.. */
 337                switch (__frame->gr8) {
 338                case -ERESTART_RESTARTBLOCK:
 339                case -ERESTARTNOHAND:
 340                        __frame->gr8 = -EINTR;
 341                        break;
 342
 343                case -ERESTARTSYS:
 344                        if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
 345                                __frame->gr8 = -EINTR;
 346                                break;
 347                        }
 348
 349                        /* fallthrough */
 350                case -ERESTARTNOINTR:
 351                        __frame->gr8 = __frame->orig_gr8;
 352                        __frame->pc -= 4;
 353                }
 354                __frame->syscallno = -1;
 355        }
 356
 357        /* Set up the stack frame */
 358        if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 359                ret = setup_rt_frame(ksig, oldset);
 360        else
 361                ret = setup_frame(ksig, oldset);
 362
 363        signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
 364} /* end handle_signal() */
 365
 366/*****************************************************************************/
 367/*
 368 * Note that 'init' is a special process: it doesn't get signals it doesn't
 369 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 370 * mistake.
 371 */
 372static void do_signal(void)
 373{
 374        struct ksignal ksig;
 375
 376        if (get_signal(&ksig)) {
 377                handle_signal(&ksig);
 378                return;
 379        }
 380
 381        /* Did we come from a system call? */
 382        if (__frame->syscallno != -1) {
 383                /* Restart the system call - no handlers present */
 384                switch (__frame->gr8) {
 385                case -ERESTARTNOHAND:
 386                case -ERESTARTSYS:
 387                case -ERESTARTNOINTR:
 388                        __frame->gr8 = __frame->orig_gr8;
 389                        __frame->pc -= 4;
 390                        break;
 391
 392                case -ERESTART_RESTARTBLOCK:
 393                        __frame->gr7 = __NR_restart_syscall;
 394                        __frame->pc -= 4;
 395                        break;
 396                }
 397                __frame->syscallno = -1;
 398        }
 399
 400        /* if there's no signal to deliver, we just put the saved sigmask
 401         * back */
 402        restore_saved_sigmask();
 403} /* end do_signal() */
 404
 405/*****************************************************************************/
 406/*
 407 * notification of userspace execution resumption
 408 * - triggered by the TIF_WORK_MASK flags
 409 */
 410asmlinkage void do_notify_resume(__u32 thread_info_flags)
 411{
 412        /* pending single-step? */
 413        if (thread_info_flags & _TIF_SINGLESTEP)
 414                clear_thread_flag(TIF_SINGLESTEP);
 415
 416        /* deal with pending signal delivery */
 417        if (thread_info_flags & _TIF_SIGPENDING)
 418                do_signal();
 419
 420        /* deal with notification on about to resume userspace execution */
 421        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 422                clear_thread_flag(TIF_NOTIFY_RESUME);
 423                tracehook_notify_resume(__frame);
 424        }
 425
 426} /* end do_notify_resume() */
 427