/*
 *  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/extable.h>
#include <linux/tracehook.h>

#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.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 fixup_exception(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;
}

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));
        } else {
                /* CPU_IS_COLDFIRE */
#if defined(CONFIG_CACHE_COPYBACK)
                flush_cf_dcache(0, DCACHE_MAX_ADDR);
#endif
                /* Invalidate instruction cache for the pushed bytes */
                clear_cf_icache(vaddr, vaddr + 8);
        }
}

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)
{
        /*
         * 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 */

/*
 * 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 inline void siginfo_build_tests(void)
{
        /*
         * This needs to be tested on m68k as it has a lesser
         * alignment requirement than x86 and that can cause surprises.
         */

        /* This is part of the ABI and can never change in size: */
        BUILD_BUG_ON(sizeof(siginfo_t) != 128);

        /* Ensure the known fields never change in location */
        BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
        BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
        BUILD_BUG_ON(offsetof(siginfo_t, si_code)  != 8);

        /* _kill */
        BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x0c);
        BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x10);

        /* _timer */
        BUILD_BUG_ON(offsetof(siginfo_t, si_tid)     != 0x0c);
        BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x10);
        BUILD_BUG_ON(offsetof(siginfo_t, si_value)   != 0x14);

        /* _rt */
        BUILD_BUG_ON(offsetof(siginfo_t, si_pid)   != 0x0c);
        BUILD_BUG_ON(offsetof(siginfo_t, si_uid)   != 0x10);
        BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x14);

        /* _sigchld */
        BUILD_BUG_ON(offsetof(siginfo_t, si_pid)    != 0x0c);
        BUILD_BUG_ON(offsetof(siginfo_t, si_uid)    != 0x10);
        BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x14);
        BUILD_BUG_ON(offsetof(siginfo_t, si_utime)  != 0x18);
        BUILD_BUG_ON(offsetof(siginfo_t, si_stime)  != 0x1c);

        /* _sigfault */
        BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x0c);

        /* _sigfault._mcerr */
        BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x10);

        /* _sigfault._addr_bnd */
        BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x12);
        BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x16);

        /* _sigfault._addr_pkey */
        BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x12);

        /* _sigpoll */
        BUILD_BUG_ON(offsetof(siginfo_t, si_band)   != 0x0c);
        BUILD_BUG_ON(offsetof(siginfo_t, si_fd)     != 0x10);

        /* _sigsys */
        BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x0c);
        BUILD_BUG_ON(offsetof(siginfo_t, si_syscall)   != 0x10);
        BUILD_BUG_ON(offsetof(siginfo_t, si_arch)      != 0x14);

        /* any new si_fields should be added here */
}

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
                 */
                pr_debug("user process returning with weird frame format\n");
                return 1;
        }
        if (!fsize) {
                regs->format = formatvec >> 12;
                regs->vector = formatvec & 0xfff;
        } else {
                struct switch_stack *sw = (struct switch_stack *)regs - 1;
                /* yes, twice as much as max(sizeof(frame.un.fmt<x>)) */
                unsigned long buf[sizeof(((struct frame *)0)->un) / 2];

                /* 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;

        siginfo_build_tests();

        /* Always make any pending restarted system calls return -EINTR */
        current->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->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);
        err |= restore_altstack(&uc->uc_stack);

        if (err)
                goto badframe;

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

        return 0;

badframe:
        return 1;
}

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

        if (!access_ok(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);
        return 0;
}

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

        if (!access_ok(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);
        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 ksignal *ksig, size_t frame_size)
{
        unsigned long usp = sigsp(rdusp(), ksig);

        return (void __user *)((usp - frame_size) & -8UL);
}

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

        if (fsize < 0) {
                pr_debug("setup_frame: Unknown frame format %#x\n",
                         regs->format);
                return -EFAULT;
        }

        frame = get_sigframe(ksig, sizeof(*frame) + fsize);

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

        err |= __put_user(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)
                return -EFAULT;

        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) ksig->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);
                pr_debug("Performing stackadjust=%04lx\n", regs->stkadj);
                /* 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;
}

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

        if (fsize < 0) {
                pr_debug("setup_frame: Unknown frame format %#x\n",
                         regs->format);
                return -EFAULT;
        }

        frame = get_sigframe(ksig, sizeof(*frame));

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

        err |= __put_user(sig, &frame->sig);
        err |= __put_user(&frame->info, &frame->pinfo);
        err |= __put_user(&frame->uc, &frame->puc);
        err |= copy_siginfo_to_user(&frame->info, &ksig->info);

        /* Create the ucontext.  */
        err |= __put_user(0, &frame->uc.uc_flags);
        err |= __put_user(NULL, &frame->uc.uc_link);
        err |= __save_altstack(&frame->uc.uc_stack, rdusp());
        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)
                return -EFAULT;

        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) ksig->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);
                pr_debug("Performing stackadjust=%04lx\n", regs->stkadj);
                /* 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;
}

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(struct ksignal *ksig, 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, &ksig->ka, 1);

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

        signal_setup_done(err, ksig, 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)
{
        struct ksignal ksig;

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

        if (get_signal(&ksig)) {
                /* Whee!  Actually deliver the signal.  */
                handle_signal(&ksig, 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);
}