signal.c

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/*
 *  linux/arch/m68k/kernel/signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

/*
 * Linux/m68k support by Hamish Macdonald
 *
 * 68060 fixes by Jesper Skov
 *
 * 1997-12-01  Modified for POSIX.1b signals by Andreas Schwab
 *
 * mathemu support by Roman Zippel
 *  (Note: fpstate in the signal context is completely ignored for the emulator
 *         and the internal floating point format is put on stack)
 */

/*
 * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
 * Atari :-) Current limitation: Only one sigstack can be active at one time.
 * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
 * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
 * signal handlers!
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/module.h>
#include <linux/tracehook.h>

#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/ucontext.h>

#ifdef CONFIG_MMU

/*
 * Handle the slight differences in classic 68k and ColdFire trap frames.
 */
#ifdef CONFIG_COLDFIRE
#define FORMAT      4
#define FMT4SIZE    0
#else
#define FORMAT      0
#define FMT4SIZE    sizeof(((struct frame *)0)->un.fmt4)
#endif

static const int frame_size_change[16] = {
  [1]   = -1, /* sizeof(((struct frame *)0)->un.fmt1), */
  [2]   = sizeof(((struct frame *)0)->un.fmt2),
  [3]   = sizeof(((struct frame *)0)->un.fmt3),
  [4]   = FMT4SIZE,
  [5]   = -1, /* sizeof(((struct frame *)0)->un.fmt5), */
  [6]   = -1, /* sizeof(((struct frame *)0)->un.fmt6), */
  [7]   = sizeof(((struct frame *)0)->un.fmt7),
  [8]   = -1, /* sizeof(((struct frame *)0)->un.fmt8), */
  [9]   = sizeof(((struct frame *)0)->un.fmt9),
  [10]  = sizeof(((struct frame *)0)->un.fmta),
  [11]  = sizeof(((struct frame *)0)->un.fmtb),
  [12]  = -1, /* sizeof(((struct frame *)0)->un.fmtc), */
  [13]  = -1, /* sizeof(((struct frame *)0)->un.fmtd), */
  [14]  = -1, /* sizeof(((struct frame *)0)->un.fmte), */
  [15]  = -1, /* sizeof(((struct frame *)0)->un.fmtf), */
};

static inline int frame_extra_sizes(int f)
{
    return frame_size_change[f];
}

int handle_kernel_fault(struct pt_regs *regs)
{
    const struct exception_table_entry *fixup;
    struct pt_regs *tregs;

    /* Are we prepared to handle this kernel fault? */
    fixup = search_exception_tables(regs->pc);
    if (!fixup)
        return 0;

    /* Create a new four word stack frame, discarding the old one. */
    regs->stkadj = frame_extra_sizes(regs->format);
    tregs = (struct pt_regs *)((long)regs + regs->stkadj);
    tregs->vector = regs->vector;
    tregs->format = FORMAT;
    tregs->pc = fixup->fixup;
    tregs->sr = regs->sr;

    return 1;
}

void ptrace_signal_deliver(struct pt_regs *regs, void *cookie)
{
    if (regs->orig_d0 < 0)
        return;
    switch (regs->d0) {
    case -ERESTARTNOHAND:
    case -ERESTARTSYS:
    case -ERESTARTNOINTR:
        regs->d0 = regs->orig_d0;
        regs->orig_d0 = -1;
        regs->pc -= 2;
        break;
    }
}

static inline void push_cache (unsigned long vaddr)
{
    /*
     * Using the old cache_push_v() was really a big waste.
     *
     * What we are trying to do is to flush 8 bytes to ram.
     * Flushing 2 cache lines of 16 bytes is much cheaper than
     * flushing 1 or 2 pages, as previously done in
     * cache_push_v().
     *                                                     Jes
     */
    if (CPU_IS_040) {
        unsigned long temp;

        __asm__ __volatile__ (".chip 68040\n\t"
                      "nop\n\t"
                      "ptestr (%1)\n\t"
                      "movec %%mmusr,%0\n\t"
                      ".chip 68k"
                      : "=r" (temp)
                      : "a" (vaddr));

        temp &= PAGE_MASK;
        temp |= vaddr & ~PAGE_MASK;

        __asm__ __volatile__ (".chip 68040\n\t"
                      "nop\n\t"
                      "cpushl %%bc,(%0)\n\t"
                      ".chip 68k"
                      : : "a" (temp));
    }
    else if (CPU_IS_060) {
        unsigned long temp;
        __asm__ __volatile__ (".chip 68060\n\t"
                      "plpar (%0)\n\t"
                      ".chip 68k"
                      : "=a" (temp)
                      : "0" (vaddr));
        __asm__ __volatile__ (".chip 68060\n\t"
                      "cpushl %%bc,(%0)\n\t"
                      ".chip 68k"
                      : : "a" (temp));
    } else if (!CPU_IS_COLDFIRE) {
        /*
         * 68030/68020 have no writeback cache;
         * still need to clear icache.
         * Note that vaddr is guaranteed to be long word aligned.
         */
        unsigned long temp;
        asm volatile ("movec %%cacr,%0" : "=r" (temp));
        temp += 4;
        asm volatile ("movec %0,%%caar\n\t"
                  "movec %1,%%cacr"
                  : : "r" (vaddr), "r" (temp));
        asm volatile ("movec %0,%%caar\n\t"
                  "movec %1,%%cacr"
                  : : "r" (vaddr + 4), "r" (temp));
    }
}

static inline void adjustformat(struct pt_regs *regs)
{
}

static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
{
}

#else /* CONFIG_MMU */

void ret_from_user_signal(void);
void ret_from_user_rt_signal(void);

static inline int frame_extra_sizes(int f)
{
    /* No frame size adjustments required on non-MMU CPUs */
    return 0;
}

static inline void adjustformat(struct pt_regs *regs)
{
    ((struct switch_stack *)regs - 1)->a5 = current->mm->start_data;
    /*
     * set format byte to make stack appear modulo 4, which it will
     * be when doing the rte
     */
    regs->format = 0x4;
}

static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
{
    sc->sc_a5 = ((struct switch_stack *)regs - 1)->a5;
}

static inline void push_cache(unsigned long vaddr)
{
}

#endif /* CONFIG_MMU */

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
asmlinkage int
sys_sigsuspend(int unused0, int unused1, old_sigset_t mask)
{
    sigset_t blocked;
    siginitset(&blocked, mask);
    return sigsuspend(&blocked);
}

asmlinkage int
sys_sigaction(int sig, const struct old_sigaction __user *act,
          struct old_sigaction __user *oact)
{
    struct k_sigaction new_ka, old_ka;
    int ret;

    if (act) {
        old_sigset_t mask;
        if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
            __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
            __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
            __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
            __get_user(mask, &act->sa_mask))
            return -EFAULT;
        siginitset(&new_ka.sa.sa_mask, mask);
    }

    ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

    if (!ret && oact) {
        if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
            __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
            __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
            __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
            __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
            return -EFAULT;
    }

    return ret;
}

asmlinkage int
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
    return do_sigaltstack(uss, uoss, rdusp());
}


/*
 * Do a signal return; undo the signal stack.
 *
 * Keep the return code on the stack quadword aligned!
 * That makes the cache flush below easier.
 */

struct sigframe
{
    char __user *pretcode;
    int sig;
    int code;
    struct sigcontext __user *psc;
    char retcode[8];
    unsigned long extramask[_NSIG_WORDS-1];
    struct sigcontext sc;
};

struct rt_sigframe
{
    char __user *pretcode;
    int sig;
    struct siginfo __user *pinfo;
    void __user *puc;
    char retcode[8];
    struct siginfo info;
    struct ucontext uc;
};

#define FPCONTEXT_SIZE  216
#define uc_fpstate  uc_filler[0]
#define uc_formatvec    uc_filler[FPCONTEXT_SIZE/4]
#define uc_extra    uc_filler[FPCONTEXT_SIZE/4+1]

#ifdef CONFIG_FPU

static unsigned char fpu_version;   /* version number of fpu, set by setup_frame */

static inline int restore_fpu_state(struct sigcontext *sc)
{
    int err = 1;

    if (FPU_IS_EMU) {
        /* restore registers */
        memcpy(current->thread.fpcntl, sc->sc_fpcntl, 12);
        memcpy(current->thread.fp, sc->sc_fpregs, 24);
        return 0;
    }

    if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
        /* Verify the frame format.  */
        if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
         (sc->sc_fpstate[0] != fpu_version))
        goto out;
        if (CPU_IS_020_OR_030) {
        if (m68k_fputype & FPU_68881 &&
            !(sc->sc_fpstate[1] == 0x18 || sc->sc_fpstate[1] == 0xb4))
            goto out;
        if (m68k_fputype & FPU_68882 &&
            !(sc->sc_fpstate[1] == 0x38 || sc->sc_fpstate[1] == 0xd4))
            goto out;
        } else if (CPU_IS_040) {
        if (!(sc->sc_fpstate[1] == 0x00 ||
                      sc->sc_fpstate[1] == 0x28 ||
                      sc->sc_fpstate[1] == 0x60))
            goto out;
        } else if (CPU_IS_060) {
        if (!(sc->sc_fpstate[3] == 0x00 ||
                      sc->sc_fpstate[3] == 0x60 ||
              sc->sc_fpstate[3] == 0xe0))
            goto out;
        } else if (CPU_IS_COLDFIRE) {
        if (!(sc->sc_fpstate[0] == 0x00 ||
              sc->sc_fpstate[0] == 0x05 ||
              sc->sc_fpstate[0] == 0xe5))
            goto out;
        } else
        goto out;

        if (CPU_IS_COLDFIRE) {
        __asm__ volatile ("fmovemd %0,%%fp0-%%fp1\n\t"
                  "fmovel %1,%%fpcr\n\t"
                  "fmovel %2,%%fpsr\n\t"
                  "fmovel %3,%%fpiar"
                  : /* no outputs */
                  : "m" (sc->sc_fpregs[0]),
                    "m" (sc->sc_fpcntl[0]),
                    "m" (sc->sc_fpcntl[1]),
                    "m" (sc->sc_fpcntl[2]));
        } else {
        __asm__ volatile (".chip 68k/68881\n\t"
                  "fmovemx %0,%%fp0-%%fp1\n\t"
                  "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
                  ".chip 68k"
                  : /* no outputs */
                  : "m" (*sc->sc_fpregs),
                    "m" (*sc->sc_fpcntl));
        }
    }

    if (CPU_IS_COLDFIRE) {
        __asm__ volatile ("frestore %0" : : "m" (*sc->sc_fpstate));
    } else {
        __asm__ volatile (".chip 68k/68881\n\t"
                  "frestore %0\n\t"
                  ".chip 68k"
                  : : "m" (*sc->sc_fpstate));
    }
    err = 0;

out:
    return err;
}

static inline int rt_restore_fpu_state(struct ucontext __user *uc)
{
    unsigned char fpstate[FPCONTEXT_SIZE];
    int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
    fpregset_t fpregs;
    int err = 1;

    if (FPU_IS_EMU) {
        /* restore fpu control register */
        if (__copy_from_user(current->thread.fpcntl,
                uc->uc_mcontext.fpregs.f_fpcntl, 12))
            goto out;
        /* restore all other fpu register */
        if (__copy_from_user(current->thread.fp,
                uc->uc_mcontext.fpregs.f_fpregs, 96))
            goto out;
        return 0;
    }

    if (__get_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate))
        goto out;
    if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
        if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
            context_size = fpstate[1];
        /* Verify the frame format.  */
        if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
             (fpstate[0] != fpu_version))
            goto out;
        if (CPU_IS_020_OR_030) {
            if (m68k_fputype & FPU_68881 &&
                !(context_size == 0x18 || context_size == 0xb4))
                goto out;
            if (m68k_fputype & FPU_68882 &&
                !(context_size == 0x38 || context_size == 0xd4))
                goto out;
        } else if (CPU_IS_040) {
            if (!(context_size == 0x00 ||
                  context_size == 0x28 ||
                  context_size == 0x60))
                goto out;
        } else if (CPU_IS_060) {
            if (!(fpstate[3] == 0x00 ||
                  fpstate[3] == 0x60 ||
                  fpstate[3] == 0xe0))
                goto out;
        } else if (CPU_IS_COLDFIRE) {
            if (!(fpstate[3] == 0x00 ||
                  fpstate[3] == 0x05 ||
                  fpstate[3] == 0xe5))
                goto out;
        } else
            goto out;
        if (__copy_from_user(&fpregs, &uc->uc_mcontext.fpregs,
                     sizeof(fpregs)))
            goto out;

        if (CPU_IS_COLDFIRE) {
            __asm__ volatile ("fmovemd %0,%%fp0-%%fp7\n\t"
                      "fmovel %1,%%fpcr\n\t"
                      "fmovel %2,%%fpsr\n\t"
                      "fmovel %3,%%fpiar"
                      : /* no outputs */
                      : "m" (fpregs.f_fpregs[0]),
                        "m" (fpregs.f_fpcntl[0]),
                        "m" (fpregs.f_fpcntl[1]),
                        "m" (fpregs.f_fpcntl[2]));
        } else {
            __asm__ volatile (".chip 68k/68881\n\t"
                      "fmovemx %0,%%fp0-%%fp7\n\t"
                      "fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
                      ".chip 68k"
                      : /* no outputs */
                      : "m" (*fpregs.f_fpregs),
                        "m" (*fpregs.f_fpcntl));
        }
    }
    if (context_size &&
        __copy_from_user(fpstate + 4, (long __user *)&uc->uc_fpstate + 1,
                 context_size))
        goto out;

    if (CPU_IS_COLDFIRE) {
        __asm__ volatile ("frestore %0" : : "m" (*fpstate));
    } else {
        __asm__ volatile (".chip 68k/68881\n\t"
                  "frestore %0\n\t"
                  ".chip 68k"
                  : : "m" (*fpstate));
    }
    err = 0;

out:
    return err;
}

/*
 * Set up a signal frame.
 */
static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
{
    if (FPU_IS_EMU) {
        /* save registers */
        memcpy(sc->sc_fpcntl, current->thread.fpcntl, 12);
        memcpy(sc->sc_fpregs, current->thread.fp, 24);
        return;
    }

    if (CPU_IS_COLDFIRE) {
        __asm__ volatile ("fsave %0"
                  : : "m" (*sc->sc_fpstate) : "memory");
    } else {
        __asm__ volatile (".chip 68k/68881\n\t"
                  "fsave %0\n\t"
                  ".chip 68k"
                  : : "m" (*sc->sc_fpstate) : "memory");
    }

    if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
        fpu_version = sc->sc_fpstate[0];
        if (CPU_IS_020_OR_030 &&
            regs->vector >= (VEC_FPBRUC * 4) &&
            regs->vector <= (VEC_FPNAN * 4)) {
            /* Clear pending exception in 68882 idle frame */
            if (*(unsigned short *) sc->sc_fpstate == 0x1f38)
                sc->sc_fpstate[0x38] |= 1 << 3;
        }

        if (CPU_IS_COLDFIRE) {
            __asm__ volatile ("fmovemd %%fp0-%%fp1,%0\n\t"
                      "fmovel %%fpcr,%1\n\t"
                      "fmovel %%fpsr,%2\n\t"
                      "fmovel %%fpiar,%3"
                      : "=m" (sc->sc_fpregs[0]),
                        "=m" (sc->sc_fpcntl[0]),
                        "=m" (sc->sc_fpcntl[1]),
                        "=m" (sc->sc_fpcntl[2])
                      : /* no inputs */
                      : "memory");
        } else {
            __asm__ volatile (".chip 68k/68881\n\t"
                      "fmovemx %%fp0-%%fp1,%0\n\t"
                      "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
                      ".chip 68k"
                      : "=m" (*sc->sc_fpregs),
                        "=m" (*sc->sc_fpcntl)
                      : /* no inputs */
                      : "memory");
        }
    }
}

static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
{
    unsigned char fpstate[FPCONTEXT_SIZE];
    int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
    int err = 0;

    if (FPU_IS_EMU) {
        /* save fpu control register */
        err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpcntl,
                current->thread.fpcntl, 12);
        /* save all other fpu register */
        err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpregs,
                current->thread.fp, 96);
        return err;
    }

    if (CPU_IS_COLDFIRE) {
        __asm__ volatile ("fsave %0" : : "m" (*fpstate) : "memory");
    } else {
        __asm__ volatile (".chip 68k/68881\n\t"
                  "fsave %0\n\t"
                  ".chip 68k"
                  : : "m" (*fpstate) : "memory");
    }

    err |= __put_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate);
    if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
        fpregset_t fpregs;
        if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
            context_size = fpstate[1];
        fpu_version = fpstate[0];
        if (CPU_IS_020_OR_030 &&
            regs->vector >= (VEC_FPBRUC * 4) &&
            regs->vector <= (VEC_FPNAN * 4)) {
            /* Clear pending exception in 68882 idle frame */
            if (*(unsigned short *) fpstate == 0x1f38)
                fpstate[0x38] |= 1 << 3;
        }
        if (CPU_IS_COLDFIRE) {
            __asm__ volatile ("fmovemd %%fp0-%%fp7,%0\n\t"
                      "fmovel %%fpcr,%1\n\t"
                      "fmovel %%fpsr,%2\n\t"
                      "fmovel %%fpiar,%3"
                      : "=m" (fpregs.f_fpregs[0]),
                        "=m" (fpregs.f_fpcntl[0]),
                        "=m" (fpregs.f_fpcntl[1]),
                        "=m" (fpregs.f_fpcntl[2])
                      : /* no inputs */
                      : "memory");
        } else {
            __asm__ volatile (".chip 68k/68881\n\t"
                      "fmovemx %%fp0-%%fp7,%0\n\t"
                      "fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
                      ".chip 68k"
                      : "=m" (*fpregs.f_fpregs),
                        "=m" (*fpregs.f_fpcntl)
                      : /* no inputs */
                      : "memory");
        }
        err |= copy_to_user(&uc->uc_mcontext.fpregs, &fpregs,
                    sizeof(fpregs));
    }
    if (context_size)
        err |= copy_to_user((long __user *)&uc->uc_fpstate + 1, fpstate + 4,
                    context_size);
    return err;
}

#else /* CONFIG_FPU */

/*
 * For the case with no FPU configured these all do nothing.
 */
static inline int restore_fpu_state(struct sigcontext *sc)
{
    return 0;
}

static inline int rt_restore_fpu_state(struct ucontext __user *uc)
{
    return 0;
}

static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
{
}

static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
{
    return 0;
}

#endif /* CONFIG_FPU */

static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,
                   void __user *fp)
{
    int fsize = frame_extra_sizes(formatvec >> 12);
    if (fsize < 0) {
        /*
         * user process trying to return with weird frame format
         */
#ifdef DEBUG
        printk("user process returning with weird frame format\n");
#endif
        return 1;
    }
    if (!fsize) {
        regs->format = formatvec >> 12;
        regs->vector = formatvec & 0xfff;
    } else {
        struct switch_stack *sw = (struct switch_stack *)regs - 1;
        unsigned long buf[fsize / 2]; /* yes, twice as much */

        /* that'll make sure that expansion won't crap over data */
        if (copy_from_user(buf + fsize / 4, fp, fsize))
            return 1;

        /* point of no return */
        regs->format = formatvec >> 12;
        regs->vector = formatvec & 0xfff;
#define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack))
        __asm__ __volatile__ (
#ifdef CONFIG_COLDFIRE
             "   movel %0,%/sp\n\t"
             "   bra ret_from_signal\n"
#else
             "   movel %0,%/a0\n\t"
             "   subl %1,%/a0\n\t"     /* make room on stack */
             "   movel %/a0,%/sp\n\t"  /* set stack pointer */
             /* move switch_stack and pt_regs */
             "1: movel %0@+,%/a0@+\n\t"
             "   dbra %2,1b\n\t"
             "   lea %/sp@(%c3),%/a0\n\t" /* add offset of fmt */
             "   lsrl  #2,%1\n\t"
             "   subql #1,%1\n\t"
             /* copy to the gap we'd made */
             "2: movel %4@+,%/a0@+\n\t"
             "   dbra %1,2b\n\t"
             "   bral ret_from_signal\n"
#endif
             : /* no outputs, it doesn't ever return */
             : "a" (sw), "d" (fsize), "d" (frame_offset/4-1),
               "n" (frame_offset), "a" (buf + fsize/4)
             : "a0");
#undef frame_offset
    }
    return 0;
}

static inline int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp)
{
    int formatvec;
    struct sigcontext context;
    int err = 0;

    /* Always make any pending restarted system calls return -EINTR */
    current_thread_info()->restart_block.fn = do_no_restart_syscall;

    /* get previous context */
    if (copy_from_user(&context, usc, sizeof(context)))
        goto badframe;

    /* restore passed registers */
    regs->d0 = context.sc_d0;
    regs->d1 = context.sc_d1;
    regs->a0 = context.sc_a0;
    regs->a1 = context.sc_a1;
    regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
    regs->pc = context.sc_pc;
    regs->orig_d0 = -1;     /* disable syscall checks */
    wrusp(context.sc_usp);
    formatvec = context.sc_formatvec;

    err = restore_fpu_state(&context);

    if (err || mangle_kernel_stack(regs, formatvec, fp))
        goto badframe;

    return 0;

badframe:
    return 1;
}

static inline int
rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
            struct ucontext __user *uc)
{
    int temp;
    greg_t __user *gregs = uc->uc_mcontext.gregs;
    unsigned long usp;
    int err;

    /* Always make any pending restarted system calls return -EINTR */
    current_thread_info()->restart_block.fn = do_no_restart_syscall;

    err = __get_user(temp, &uc->uc_mcontext.version);
    if (temp != MCONTEXT_VERSION)
        goto badframe;
    /* restore passed registers */
    err |= __get_user(regs->d0, &gregs[0]);
    err |= __get_user(regs->d1, &gregs[1]);
    err |= __get_user(regs->d2, &gregs[2]);
    err |= __get_user(regs->d3, &gregs[3]);
    err |= __get_user(regs->d4, &gregs[4]);
    err |= __get_user(regs->d5, &gregs[5]);
    err |= __get_user(sw->d6, &gregs[6]);
    err |= __get_user(sw->d7, &gregs[7]);
    err |= __get_user(regs->a0, &gregs[8]);
    err |= __get_user(regs->a1, &gregs[9]);
    err |= __get_user(regs->a2, &gregs[10]);
    err |= __get_user(sw->a3, &gregs[11]);
    err |= __get_user(sw->a4, &gregs[12]);
    err |= __get_user(sw->a5, &gregs[13]);
    err |= __get_user(sw->a6, &gregs[14]);
    err |= __get_user(usp, &gregs[15]);
    wrusp(usp);
    err |= __get_user(regs->pc, &gregs[16]);
    err |= __get_user(temp, &gregs[17]);
    regs->sr = (regs->sr & 0xff00) | (temp & 0xff);
    regs->orig_d0 = -1;     /* disable syscall checks */
    err |= __get_user(temp, &uc->uc_formatvec);

    err |= rt_restore_fpu_state(uc);

    if (err || do_sigaltstack(&uc->uc_stack, NULL, usp) == -EFAULT)
        goto badframe;

    if (mangle_kernel_stack(regs, temp, &uc->uc_extra))
        goto badframe;

    return 0;

badframe:
    return 1;
}

asmlinkage int do_sigreturn(unsigned long __unused)
{
    struct switch_stack *sw = (struct switch_stack *) &__unused;
    struct pt_regs *regs = (struct pt_regs *) (sw + 1);
    unsigned long usp = rdusp();
    struct sigframe __user *frame = (struct sigframe __user *)(usp - 4);
    sigset_t set;

    if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
        goto badframe;
    if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
        (_NSIG_WORDS > 1 &&
         __copy_from_user(&set.sig[1], &frame->extramask,
                  sizeof(frame->extramask))))
        goto badframe;

    set_current_blocked(&set);

    if (restore_sigcontext(regs, &frame->sc, frame + 1))
        goto badframe;
    return regs->d0;

badframe:
    force_sig(SIGSEGV, current);
    return 0;
}

asmlinkage int do_rt_sigreturn(unsigned long __unused)
{
    struct switch_stack *sw = (struct switch_stack *) &__unused;
    struct pt_regs *regs = (struct pt_regs *) (sw + 1);
    unsigned long usp = rdusp();
    struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(usp - 4);
    sigset_t set;

    if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
        goto badframe;
    if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
        goto badframe;

    set_current_blocked(&set);

    if (rt_restore_ucontext(regs, sw, &frame->uc))
        goto badframe;
    return regs->d0;

badframe:
    force_sig(SIGSEGV, current);
    return 0;
}

static void setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
                 unsigned long mask)
{
    sc->sc_mask = mask;
    sc->sc_usp = rdusp();
    sc->sc_d0 = regs->d0;
    sc->sc_d1 = regs->d1;
    sc->sc_a0 = regs->a0;
    sc->sc_a1 = regs->a1;
    sc->sc_sr = regs->sr;
    sc->sc_pc = regs->pc;
    sc->sc_formatvec = regs->format << 12 | regs->vector;
    save_a5_state(sc, regs);
    save_fpu_state(sc, regs);
}

static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
{
    struct switch_stack *sw = (struct switch_stack *)regs - 1;
    greg_t __user *gregs = uc->uc_mcontext.gregs;
    int err = 0;

    err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
    err |= __put_user(regs->d0, &gregs[0]);
    err |= __put_user(regs->d1, &gregs[1]);
    err |= __put_user(regs->d2, &gregs[2]);
    err |= __put_user(regs->d3, &gregs[3]);
    err |= __put_user(regs->d4, &gregs[4]);
    err |= __put_user(regs->d5, &gregs[5]);
    err |= __put_user(sw->d6, &gregs[6]);
    err |= __put_user(sw->d7, &gregs[7]);
    err |= __put_user(regs->a0, &gregs[8]);
    err |= __put_user(regs->a1, &gregs[9]);
    err |= __put_user(regs->a2, &gregs[10]);
    err |= __put_user(sw->a3, &gregs[11]);
    err |= __put_user(sw->a4, &gregs[12]);
    err |= __put_user(sw->a5, &gregs[13]);
    err |= __put_user(sw->a6, &gregs[14]);
    err |= __put_user(rdusp(), &gregs[15]);
    err |= __put_user(regs->pc, &gregs[16]);
    err |= __put_user(regs->sr, &gregs[17]);
    err |= __put_user((regs->format << 12) | regs->vector, &uc->uc_formatvec);
    err |= rt_save_fpu_state(uc, regs);
    return err;
}

static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
{
    unsigned long usp;

    /* Default to using normal stack.  */
    usp = rdusp();

    /* This is the X/Open sanctioned signal stack switching.  */
    if (ka->sa.sa_flags & SA_ONSTACK) {
        if (!sas_ss_flags(usp))
            usp = current->sas_ss_sp + current->sas_ss_size;
    }
    return (void __user *)((usp - frame_size) & -8UL);
}

static int setup_frame (int sig, struct k_sigaction *ka,
             sigset_t *set, struct pt_regs *regs)
{
    struct sigframe __user *frame;
    int fsize = frame_extra_sizes(regs->format);
    struct sigcontext context;
    int err = 0;

    if (fsize < 0) {
#ifdef DEBUG
        printk ("setup_frame: Unknown frame format %#x\n",
            regs->format);
#endif
        goto give_sigsegv;
    }

    frame = get_sigframe(ka, regs, sizeof(*frame) + fsize);

    if (fsize)
        err |= copy_to_user (frame + 1, regs + 1, fsize);

    err |= __put_user((current_thread_info()->exec_domain
               && current_thread_info()->exec_domain->signal_invmap
               && sig < 32
               ? current_thread_info()->exec_domain->signal_invmap[sig]
               : sig),
              &frame->sig);

    err |= __put_user(regs->vector, &frame->code);
    err |= __put_user(&frame->sc, &frame->psc);

    if (_NSIG_WORDS > 1)
        err |= copy_to_user(frame->extramask, &set->sig[1],
                    sizeof(frame->extramask));

    setup_sigcontext(&context, regs, set->sig[0]);
    err |= copy_to_user (&frame->sc, &context, sizeof(context));

    /* Set up to return from userspace.  */
#ifdef CONFIG_MMU
    err |= __put_user(frame->retcode, &frame->pretcode);
    /* moveq #,d0; trap #0 */
    err |= __put_user(0x70004e40 + (__NR_sigreturn << 16),
              (long __user *)(frame->retcode));
#else
    err |= __put_user((void *) ret_from_user_signal, &frame->pretcode);
#endif

    if (err)
        goto give_sigsegv;

    push_cache ((unsigned long) &frame->retcode);

    /*
     * Set up registers for signal handler.  All the state we are about
     * to destroy is successfully copied to sigframe.
     */
    wrusp ((unsigned long) frame);
    regs->pc = (unsigned long) ka->sa.sa_handler;
    adjustformat(regs);

    /*
     * This is subtle; if we build more than one sigframe, all but the
     * first one will see frame format 0 and have fsize == 0, so we won't
     * screw stkadj.
     */
    if (fsize)
        regs->stkadj = fsize;

    /* Prepare to skip over the extra stuff in the exception frame.  */
    if (regs->stkadj) {
        struct pt_regs *tregs =
            (struct pt_regs *)((ulong)regs + regs->stkadj);
#ifdef DEBUG
        printk("Performing stackadjust=%04x\n", regs->stkadj);
#endif
        /* This must be copied with decreasing addresses to
                   handle overlaps.  */
        tregs->vector = 0;
        tregs->format = 0;
        tregs->pc = regs->pc;
        tregs->sr = regs->sr;
    }
    return 0;

give_sigsegv:
    force_sigsegv(sig, current);
    return err;
}

static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
                sigset_t *set, struct pt_regs *regs)
{
    struct rt_sigframe __user *frame;
    int fsize = frame_extra_sizes(regs->format);
    int err = 0;

    if (fsize < 0) {
#ifdef DEBUG
        printk ("setup_frame: Unknown frame format %#x\n",
            regs->format);
#endif
        goto give_sigsegv;
    }

    frame = get_sigframe(ka, regs, sizeof(*frame));

    if (fsize)
        err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);

    err |= __put_user((current_thread_info()->exec_domain
               && current_thread_info()->exec_domain->signal_invmap
               && sig < 32
               ? current_thread_info()->exec_domain->signal_invmap[sig]
               : sig),
              &frame->sig);
    err |= __put_user(&frame->info, &frame->pinfo);
    err |= __put_user(&frame->uc, &frame->puc);
    err |= copy_siginfo_to_user(&frame->info, info);

    /* Create the ucontext.  */
    err |= __put_user(0, &frame->uc.uc_flags);
    err |= __put_user(NULL, &frame->uc.uc_link);
    err |= __put_user((void __user *)current->sas_ss_sp,
              &frame->uc.uc_stack.ss_sp);
    err |= __put_user(sas_ss_flags(rdusp()),
              &frame->uc.uc_stack.ss_flags);
    err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
    err |= rt_setup_ucontext(&frame->uc, regs);
    err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));

    /* Set up to return from userspace.  */
#ifdef CONFIG_MMU
    err |= __put_user(frame->retcode, &frame->pretcode);
#ifdef __mcoldfire__
    /* movel #__NR_rt_sigreturn,d0; trap #0 */
    err |= __put_user(0x203c0000, (long __user *)(frame->retcode + 0));
    err |= __put_user(0x00004e40 + (__NR_rt_sigreturn << 16),
              (long __user *)(frame->retcode + 4));
#else
    /* moveq #,d0; notb d0; trap #0 */
    err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
              (long __user *)(frame->retcode + 0));
    err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
#endif
#else
    err |= __put_user((void *) ret_from_user_rt_signal, &frame->pretcode);
#endif /* CONFIG_MMU */

    if (err)
        goto give_sigsegv;

    push_cache ((unsigned long) &frame->retcode);

    /*
     * Set up registers for signal handler.  All the state we are about
     * to destroy is successfully copied to sigframe.
     */
    wrusp ((unsigned long) frame);
    regs->pc = (unsigned long) ka->sa.sa_handler;
    adjustformat(regs);

    /*
     * This is subtle; if we build more than one sigframe, all but the
     * first one will see frame format 0 and have fsize == 0, so we won't
     * screw stkadj.
     */
    if (fsize)
        regs->stkadj = fsize;

    /* Prepare to skip over the extra stuff in the exception frame.  */
    if (regs->stkadj) {
        struct pt_regs *tregs =
            (struct pt_regs *)((ulong)regs + regs->stkadj);
#ifdef DEBUG
        printk("Performing stackadjust=%04x\n", regs->stkadj);
#endif
        /* This must be copied with decreasing addresses to
                   handle overlaps.  */
        tregs->vector = 0;
        tregs->format = 0;
        tregs->pc = regs->pc;
        tregs->sr = regs->sr;
    }
    return 0;

give_sigsegv:
    force_sigsegv(sig, current);
    return err;
}

static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
    switch (regs->d0) {
    case -ERESTARTNOHAND:
        if (!has_handler)
            goto do_restart;
        regs->d0 = -EINTR;
        break;

    case -ERESTART_RESTARTBLOCK:
        if (!has_handler) {
            regs->d0 = __NR_restart_syscall;
            regs->pc -= 2;
            break;
        }
        regs->d0 = -EINTR;
        break;

    case -ERESTARTSYS:
        if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
            regs->d0 = -EINTR;
            break;
        }
    /* fallthrough */
    case -ERESTARTNOINTR:
    do_restart:
        regs->d0 = regs->orig_d0;
        regs->pc -= 2;
        break;
    }
}

/*
 * OK, we're invoking a handler
 */
static void
handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
          struct pt_regs *regs)
{
    sigset_t *oldset = sigmask_to_save();
    int err;
    /* are we from a system call? */
    if (regs->orig_d0 >= 0)
        /* If so, check system call restarting.. */
        handle_restart(regs, ka, 1);

    /* set up the stack frame */
    if (ka->sa.sa_flags & SA_SIGINFO)
        err = setup_rt_frame(sig, ka, info, oldset, regs);
    else
        err = setup_frame(sig, ka, oldset, regs);

    if (err)
        return;

    signal_delivered(sig, info, ka, regs, 0);

    if (test_thread_flag(TIF_DELAYED_TRACE)) {
        regs->sr &= ~0x8000;
        send_sig(SIGTRAP, current, 1);
    }
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 */
static void do_signal(struct pt_regs *regs)
{
    siginfo_t info;
    struct k_sigaction ka;
    int signr;

    current->thread.esp0 = (unsigned long) regs;

    signr = get_signal_to_deliver(&info, &ka, regs, NULL);
    if (signr > 0) {
        /* Whee!  Actually deliver the signal.  */
        handle_signal(signr, &ka, &info, regs);
        return;
    }

    /* Did we come from a system call? */
    if (regs->orig_d0 >= 0)
        /* Restart the system call - no handlers present */
        handle_restart(regs, NULL, 0);

    /* If there's no signal to deliver, we just restore the saved mask.  */
    restore_saved_sigmask();
}

void do_notify_resume(struct pt_regs *regs)
{
    if (test_thread_flag(TIF_SIGPENDING))
        do_signal(regs);

    if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
        tracehook_notify_resume(regs);
}