/*
 *  Emulation of Linux signals
 *
 *  Copyright (c) 2003 Fabrice Bellard
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 */
#include "qemu/osdep.h"
#include <sys/ucontext.h>
#include <sys/resource.h>

#include "qemu.h"
#include "qemu-common.h"
#include "target_signal.h"
#include "trace.h"

static struct target_sigaltstack target_sigaltstack_used = {
    .ss_sp = 0,
    .ss_size = 0,
    .ss_flags = TARGET_SS_DISABLE,
};

static struct target_sigaction sigact_table[TARGET_NSIG];

static void host_signal_handler(int host_signum, siginfo_t *info,
                                void *puc);

static uint8_t host_to_target_signal_table[_NSIG] = {
    [SIGHUP] = TARGET_SIGHUP,
    [SIGINT] = TARGET_SIGINT,
    [SIGQUIT] = TARGET_SIGQUIT,
    [SIGILL] = TARGET_SIGILL,
    [SIGTRAP] = TARGET_SIGTRAP,
    [SIGABRT] = TARGET_SIGABRT,
/*    [SIGIOT] = TARGET_SIGIOT,*/
    [SIGBUS] = TARGET_SIGBUS,
    [SIGFPE] = TARGET_SIGFPE,
    [SIGKILL] = TARGET_SIGKILL,
    [SIGUSR1] = TARGET_SIGUSR1,
    [SIGSEGV] = TARGET_SIGSEGV,
    [SIGUSR2] = TARGET_SIGUSR2,
    [SIGPIPE] = TARGET_SIGPIPE,
    [SIGALRM] = TARGET_SIGALRM,
    [SIGTERM] = TARGET_SIGTERM,
#ifdef SIGSTKFLT
    [SIGSTKFLT] = TARGET_SIGSTKFLT,
#endif
    [SIGCHLD] = TARGET_SIGCHLD,
    [SIGCONT] = TARGET_SIGCONT,
    [SIGSTOP] = TARGET_SIGSTOP,
    [SIGTSTP] = TARGET_SIGTSTP,
    [SIGTTIN] = TARGET_SIGTTIN,
    [SIGTTOU] = TARGET_SIGTTOU,
    [SIGURG] = TARGET_SIGURG,
    [SIGXCPU] = TARGET_SIGXCPU,
    [SIGXFSZ] = TARGET_SIGXFSZ,
    [SIGVTALRM] = TARGET_SIGVTALRM,
    [SIGPROF] = TARGET_SIGPROF,
    [SIGWINCH] = TARGET_SIGWINCH,
    [SIGIO] = TARGET_SIGIO,
    [SIGPWR] = TARGET_SIGPWR,
    [SIGSYS] = TARGET_SIGSYS,
    /* next signals stay the same */
    /* Nasty hack: Reverse SIGRTMIN and SIGRTMAX to avoid overlap with
       host libpthread signals.  This assumes no one actually uses SIGRTMAX :-/
       To fix this properly we need to do manual signal delivery multiplexed
       over a single host signal.  */
    [__SIGRTMIN] = __SIGRTMAX,
    [__SIGRTMAX] = __SIGRTMIN,
};
static uint8_t target_to_host_signal_table[_NSIG];

static inline int on_sig_stack(unsigned long sp)
{
    return (sp - target_sigaltstack_used.ss_sp
            < target_sigaltstack_used.ss_size);
}

static inline int sas_ss_flags(unsigned long sp)
{
    return (target_sigaltstack_used.ss_size == 0 ? SS_DISABLE
            : on_sig_stack(sp) ? SS_ONSTACK : 0);
}

int host_to_target_signal(int sig)
{
    if (sig < 0 || sig >= _NSIG)
        return sig;
    return host_to_target_signal_table[sig];
}

int target_to_host_signal(int sig)
{
    if (sig < 0 || sig >= _NSIG)
        return sig;
    return target_to_host_signal_table[sig];
}

static inline void target_sigemptyset(target_sigset_t *set)
{
    memset(set, 0, sizeof(*set));
}

static inline void target_sigaddset(target_sigset_t *set, int signum)
{
    signum--;
    abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
    set->sig[signum / TARGET_NSIG_BPW] |= mask;
}

static inline int target_sigismember(const target_sigset_t *set, int signum)
{
    signum--;
    abi_ulong mask = (abi_ulong)1 << (signum % TARGET_NSIG_BPW);
    return ((set->sig[signum / TARGET_NSIG_BPW] & mask) != 0);
}

static void host_to_target_sigset_internal(target_sigset_t *d,
                                           const sigset_t *s)
{
    int i;
    target_sigemptyset(d);
    for (i = 1; i <= TARGET_NSIG; i++) {
        if (sigismember(s, i)) {
            target_sigaddset(d, host_to_target_signal(i));
        }
    }
}

void host_to_target_sigset(target_sigset_t *d, const sigset_t *s)
{
    target_sigset_t d1;
    int i;

    host_to_target_sigset_internal(&d1, s);
    for(i = 0;i < TARGET_NSIG_WORDS; i++)
        d->sig[i] = tswapal(d1.sig[i]);
}

static void target_to_host_sigset_internal(sigset_t *d,
                                           const target_sigset_t *s)
{
    int i;
    sigemptyset(d);
    for (i = 1; i <= TARGET_NSIG; i++) {
        if (target_sigismember(s, i)) {
            sigaddset(d, target_to_host_signal(i));
        }
     }
}

void target_to_host_sigset(sigset_t *d, const target_sigset_t *s)
{
    target_sigset_t s1;
    int i;

    for(i = 0;i < TARGET_NSIG_WORDS; i++)
        s1.sig[i] = tswapal(s->sig[i]);
    target_to_host_sigset_internal(d, &s1);
}

void host_to_target_old_sigset(abi_ulong *old_sigset,
                               const sigset_t *sigset)
{
    target_sigset_t d;
    host_to_target_sigset(&d, sigset);
    *old_sigset = d.sig[0];
}

void target_to_host_old_sigset(sigset_t *sigset,
                               const abi_ulong *old_sigset)
{
    target_sigset_t d;
    int i;

    d.sig[0] = *old_sigset;
    for(i = 1;i < TARGET_NSIG_WORDS; i++)
        d.sig[i] = 0;
    target_to_host_sigset(sigset, &d);
}

/* Wrapper for sigprocmask function
 * Emulates a sigprocmask in a safe way for the guest. Note that set and oldset
 * are host signal set, not guest ones. This wraps the sigprocmask host calls
 * that should be protected (calls originated from guest)
 */
int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset)
{
    int ret;
    sigset_t val;
    sigset_t *temp = NULL;
    CPUState *cpu = thread_cpu;
    TaskState *ts = (TaskState *)cpu->opaque;
    bool segv_was_blocked = ts->sigsegv_blocked;

    if (set) {
        bool has_sigsegv = sigismember(set, SIGSEGV);
        val = *set;
        temp = &val;

        sigdelset(temp, SIGSEGV);

        switch (how) {
        case SIG_BLOCK:
            if (has_sigsegv) {
                ts->sigsegv_blocked = true;
            }
            break;
        case SIG_UNBLOCK:
            if (has_sigsegv) {
                ts->sigsegv_blocked = false;
            }
            break;
        case SIG_SETMASK:
            ts->sigsegv_blocked = has_sigsegv;
            break;
        default:
            g_assert_not_reached();
        }
    }

    ret = sigprocmask(how, temp, oldset);

    if (oldset && segv_was_blocked) {
        sigaddset(oldset, SIGSEGV);
    }

    return ret;
}

/* siginfo conversion */

static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
                                                 const siginfo_t *info)
{
    int sig = host_to_target_signal(info->si_signo);
    tinfo->si_signo = sig;
    tinfo->si_errno = 0;
    tinfo->si_code = info->si_code;

    if (sig == TARGET_SIGILL || sig == TARGET_SIGFPE || sig == TARGET_SIGSEGV
        || sig == TARGET_SIGBUS || sig == TARGET_SIGTRAP) {
        /* Should never come here, but who knows. The information for
           the target is irrelevant.  */
        tinfo->_sifields._sigfault._addr = 0;
    } else if (sig == TARGET_SIGIO) {
        tinfo->_sifields._sigpoll._band = info->si_band;
        tinfo->_sifields._sigpoll._fd = info->si_fd;
    } else if (sig == TARGET_SIGCHLD) {
        tinfo->_sifields._sigchld._pid = info->si_pid;
        tinfo->_sifields._sigchld._uid = info->si_uid;
        tinfo->_sifields._sigchld._status
            = host_to_target_waitstatus(info->si_status);
        tinfo->_sifields._sigchld._utime = info->si_utime;
        tinfo->_sifields._sigchld._stime = info->si_stime;
    } else if (sig >= TARGET_SIGRTMIN) {
        tinfo->_sifields._rt._pid = info->si_pid;
        tinfo->_sifields._rt._uid = info->si_uid;
        /* XXX: potential problem if 64 bit */
        tinfo->_sifields._rt._sigval.sival_ptr
            = (abi_ulong)(unsigned long)info->si_value.sival_ptr;
    }
}

static void tswap_siginfo(target_siginfo_t *tinfo,
                          const target_siginfo_t *info)
{
    int sig = info->si_signo;
    tinfo->si_signo = tswap32(sig);
    tinfo->si_errno = tswap32(info->si_errno);
    tinfo->si_code = tswap32(info->si_code);

    if (sig == TARGET_SIGILL || sig == TARGET_SIGFPE || sig == TARGET_SIGSEGV
        || sig == TARGET_SIGBUS || sig == TARGET_SIGTRAP) {
        tinfo->_sifields._sigfault._addr
            = tswapal(info->_sifields._sigfault._addr);
    } else if (sig == TARGET_SIGIO) {
        tinfo->_sifields._sigpoll._band
            = tswap32(info->_sifields._sigpoll._band);
        tinfo->_sifields._sigpoll._fd = tswap32(info->_sifields._sigpoll._fd);
    } else if (sig == TARGET_SIGCHLD) {
        tinfo->_sifields._sigchld._pid
            = tswap32(info->_sifields._sigchld._pid);
        tinfo->_sifields._sigchld._uid
            = tswap32(info->_sifields._sigchld._uid);
        tinfo->_sifields._sigchld._status
            = tswap32(info->_sifields._sigchld._status);
        tinfo->_sifields._sigchld._utime
            = tswapal(info->_sifields._sigchld._utime);
        tinfo->_sifields._sigchld._stime
            = tswapal(info->_sifields._sigchld._stime);
    } else if (sig >= TARGET_SIGRTMIN) {
        tinfo->_sifields._rt._pid = tswap32(info->_sifields._rt._pid);
        tinfo->_sifields._rt._uid = tswap32(info->_sifields._rt._uid);
        tinfo->_sifields._rt._sigval.sival_ptr
            = tswapal(info->_sifields._rt._sigval.sival_ptr);
    }
}


void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
{
    host_to_target_siginfo_noswap(tinfo, info);
    tswap_siginfo(tinfo, tinfo);
}

/* XXX: we support only POSIX RT signals are used. */
/* XXX: find a solution for 64 bit (additional malloced data is needed) */
void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo)
{
    info->si_signo = tswap32(tinfo->si_signo);
    info->si_errno = tswap32(tinfo->si_errno);
    info->si_code = tswap32(tinfo->si_code);
    info->si_pid = tswap32(tinfo->_sifields._rt._pid);
    info->si_uid = tswap32(tinfo->_sifields._rt._uid);
    info->si_value.sival_ptr =
            (void *)(long)tswapal(tinfo->_sifields._rt._sigval.sival_ptr);
}

static int fatal_signal (int sig)
{
    switch (sig) {
    case TARGET_SIGCHLD:
    case TARGET_SIGURG:
    case TARGET_SIGWINCH:
        /* Ignored by default.  */
        return 0;
    case TARGET_SIGCONT:
    case TARGET_SIGSTOP:
    case TARGET_SIGTSTP:
    case TARGET_SIGTTIN:
    case TARGET_SIGTTOU:
        /* Job control signals.  */
        return 0;
    default:
        return 1;
    }
}

/* returns 1 if given signal should dump core if not handled */
static int core_dump_signal(int sig)
{
    switch (sig) {
    case TARGET_SIGABRT:
    case TARGET_SIGFPE:
    case TARGET_SIGILL:
    case TARGET_SIGQUIT:
    case TARGET_SIGSEGV:
    case TARGET_SIGTRAP:
    case TARGET_SIGBUS:
        return (1);
    default:
        return (0);
    }
}

void signal_init(void)
{
    struct sigaction act;
    struct sigaction oact;
    int i, j;
    int host_sig;

    /* generate signal conversion tables */
    for(i = 1; i < _NSIG; i++) {
        if (host_to_target_signal_table[i] == 0)
            host_to_target_signal_table[i] = i;
    }
    for(i = 1; i < _NSIG; i++) {
        j = host_to_target_signal_table[i];
        target_to_host_signal_table[j] = i;
    }

    /* set all host signal handlers. ALL signals are blocked during
       the handlers to serialize them. */
    memset(sigact_table, 0, sizeof(sigact_table));

    sigfillset(&act.sa_mask);
    act.sa_flags = SA_SIGINFO;
    act.sa_sigaction = host_signal_handler;
    for(i = 1; i <= TARGET_NSIG; i++) {
        host_sig = target_to_host_signal(i);
        sigaction(host_sig, NULL, &oact);
        if (oact.sa_sigaction == (void *)SIG_IGN) {
            sigact_table[i - 1]._sa_handler = TARGET_SIG_IGN;
        } else if (oact.sa_sigaction == (void *)SIG_DFL) {
            sigact_table[i - 1]._sa_handler = TARGET_SIG_DFL;
        }
        /* If there's already a handler installed then something has
           gone horribly wrong, so don't even try to handle that case.  */
        /* Install some handlers for our own use.  We need at least
           SIGSEGV and SIGBUS, to detect exceptions.  We can not just
           trap all signals because it affects syscall interrupt
           behavior.  But do trap all default-fatal signals.  */
        if (fatal_signal (i))
            sigaction(host_sig, &act, NULL);
    }
}

/* signal queue handling */

static inline struct sigqueue *alloc_sigqueue(CPUArchState *env)
{
    CPUState *cpu = ENV_GET_CPU(env);
    TaskState *ts = cpu->opaque;
    struct sigqueue *q = ts->first_free;
    if (!q)
        return NULL;
    ts->first_free = q->next;
    return q;
}

static inline void free_sigqueue(CPUArchState *env, struct sigqueue *q)
{
    CPUState *cpu = ENV_GET_CPU(env);
    TaskState *ts = cpu->opaque;

    q->next = ts->first_free;
    ts->first_free = q;
}

/* abort execution with signal */
static void QEMU_NORETURN force_sig(int target_sig)
{
    CPUState *cpu = thread_cpu;
    CPUArchState *env = cpu->env_ptr;
    TaskState *ts = (TaskState *)cpu->opaque;
    int host_sig, core_dumped = 0;
    struct sigaction act;

    host_sig = target_to_host_signal(target_sig);
    trace_user_force_sig(env, target_sig, host_sig);
    gdb_signalled(env, target_sig);

    /* dump core if supported by target binary format */
    if (core_dump_signal(target_sig) && (ts->bprm->core_dump != NULL)) {
        stop_all_tasks();
        core_dumped =
            ((*ts->bprm->core_dump)(target_sig, env) == 0);
    }
    if (core_dumped) {
        /* we already dumped the core of target process, we don't want
         * a coredump of qemu itself */
        struct rlimit nodump;
        getrlimit(RLIMIT_CORE, &nodump);
        nodump.rlim_cur=0;
        setrlimit(RLIMIT_CORE, &nodump);
        (void) fprintf(stderr, "qemu: uncaught target signal %d (%s) - %s\n",
            target_sig, strsignal(host_sig), "core dumped" );
    }

    /* The proper exit code for dying from an uncaught signal is
     * -<signal>.  The kernel doesn't allow exit() or _exit() to pass
     * a negative value.  To get the proper exit code we need to
     * actually die from an uncaught signal.  Here the default signal
     * handler is installed, we send ourself a signal and we wait for
     * it to arrive. */
    sigfillset(&act.sa_mask);
    act.sa_handler = SIG_DFL;
    act.sa_flags = 0;
    sigaction(host_sig, &act, NULL);

    /* For some reason raise(host_sig) doesn't send the signal when
     * statically linked on x86-64. */
    kill(getpid(), host_sig);

    /* Make sure the signal isn't masked (just reuse the mask inside
    of act) */
    sigdelset(&act.sa_mask, host_sig);
    sigsuspend(&act.sa_mask);

    /* unreachable */
    abort();
}

/* queue a signal so that it will be send to the virtual CPU as soon
   as possible */
int queue_signal(CPUArchState *env, int sig, target_siginfo_t *info)
{
    CPUState *cpu = ENV_GET_CPU(env);
    TaskState *ts = cpu->opaque;
    struct emulated_sigtable *k;
    struct sigqueue *q, **pq;
    abi_ulong handler;
    int queue;

    trace_user_queue_signal(env, sig);
    k = &ts->sigtab[sig - 1];
    queue = gdb_queuesig ();
    handler = sigact_table[sig - 1]._sa_handler;

    if (ts->sigsegv_blocked && sig == TARGET_SIGSEGV) {
        /* Guest has blocked SIGSEGV but we got one anyway. Assume this
         * is a forced SIGSEGV (ie one the kernel handles via force_sig_info
         * because it got a real MMU fault). A blocked SIGSEGV in that
         * situation is treated as if using the default handler. This is
         * not correct if some other process has randomly sent us a SIGSEGV
         * via kill(), but that is not easy to distinguish at this point,
         * so we assume it doesn't happen.
         */
        handler = TARGET_SIG_DFL;
    }

    if (!queue && handler == TARGET_SIG_DFL) {
        if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN || sig == TARGET_SIGTTOU) {
            kill(getpid(),SIGSTOP);
            return 0;
        } else
        /* default handler : ignore some signal. The other are fatal */
        if (sig != TARGET_SIGCHLD &&
            sig != TARGET_SIGURG &&
            sig != TARGET_SIGWINCH &&
            sig != TARGET_SIGCONT) {
            force_sig(sig);
        } else {
            return 0; /* indicate ignored */
        }
    } else if (!queue && handler == TARGET_SIG_IGN) {
        /* ignore signal */
        return 0;
    } else if (!queue && handler == TARGET_SIG_ERR) {
        force_sig(sig);
    } else {
        pq = &k->first;
        if (sig < TARGET_SIGRTMIN) {
            /* if non real time signal, we queue exactly one signal */
            if (!k->pending)
                q = &k->info;
            else
                return 0;
        } else {
            if (!k->pending) {
                /* first signal */
                q = &k->info;
            } else {
                q = alloc_sigqueue(env);
                if (!q)
                    return -EAGAIN;
                while (*pq != NULL)
                    pq = &(*pq)->next;
            }
        }
        *pq = q;
        q->info = *info;
        q->next = NULL;
        k->pending = 1;
        /* signal that a new signal is pending */
        ts->signal_pending = 1;
        return 1; /* indicates that the signal was queued */
    }
}

static void host_signal_handler(int host_signum, siginfo_t *info,
                                void *puc)
{
    CPUArchState *env = thread_cpu->env_ptr;
    int sig;
    target_siginfo_t tinfo;

    /* the CPU emulator uses some host signals to detect exceptions,
       we forward to it some signals */
    if ((host_signum == SIGSEGV || host_signum == SIGBUS)
        && info->si_code > 0) {
        if (cpu_signal_handler(host_signum, info, puc))
            return;
    }

    /* get target signal number */
    sig = host_to_target_signal(host_signum);
    if (sig < 1 || sig > TARGET_NSIG)
        return;
    trace_user_host_signal(env, host_signum, sig);
    host_to_target_siginfo_noswap(&tinfo, info);
    if (queue_signal(env, sig, &tinfo) == 1) {
        /* interrupt the virtual CPU as soon as possible */
        cpu_exit(thread_cpu);
    }
}

/* do_sigaltstack() returns target values and errnos. */
/* compare linux/kernel/signal.c:do_sigaltstack() */
abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp)
{
    int ret;
    struct target_sigaltstack oss;

    /* XXX: test errors */
    if(uoss_addr)
    {
        __put_user(target_sigaltstack_used.ss_sp, &oss.ss_sp);
        __put_user(target_sigaltstack_used.ss_size, &oss.ss_size);
        __put_user(sas_ss_flags(sp), &oss.ss_flags);
    }

    if(uss_addr)
    {
        struct target_sigaltstack *uss;
        struct target_sigaltstack ss;
        size_t minstacksize = TARGET_MINSIGSTKSZ;

#if defined(TARGET_PPC64)
        /* ELF V2 for PPC64 has a 4K minimum stack size for signal handlers */
        struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
        if (get_ppc64_abi(image) > 1) {
            minstacksize = 4096;
        }
#endif

        ret = -TARGET_EFAULT;
        if (!lock_user_struct(VERIFY_READ, uss, uss_addr, 1)) {
            goto out;
        }
        __get_user(ss.ss_sp, &uss->ss_sp);
        __get_user(ss.ss_size, &uss->ss_size);
        __get_user(ss.ss_flags, &uss->ss_flags);
        unlock_user_struct(uss, uss_addr, 0);

        ret = -TARGET_EPERM;
        if (on_sig_stack(sp))
            goto out;

        ret = -TARGET_EINVAL;
        if (ss.ss_flags != TARGET_SS_DISABLE
            && ss.ss_flags != TARGET_SS_ONSTACK
            && ss.ss_flags != 0)
            goto out;

        if (ss.ss_flags == TARGET_SS_DISABLE) {
            ss.ss_size = 0;
            ss.ss_sp = 0;
        } else {
            ret = -TARGET_ENOMEM;
            if (ss.ss_size < minstacksize) {
                goto out;
            }
        }

        target_sigaltstack_used.ss_sp = ss.ss_sp;
        target_sigaltstack_used.ss_size = ss.ss_size;
    }

    if (uoss_addr) {
        ret = -TARGET_EFAULT;
        if (copy_to_user(uoss_addr, &oss, sizeof(oss)))
            goto out;
    }

    ret = 0;
out:
    return ret;
}

/* do_sigaction() return host values and errnos */
int do_sigaction(int sig, const struct target_sigaction *act,
                 struct target_sigaction *oact)
{
    struct target_sigaction *k;
    struct sigaction act1;
    int host_sig;
    int ret = 0;

    if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP)
        return -EINVAL;
    k = &sigact_table[sig - 1];
    if (oact) {
        __put_user(k->_sa_handler, &oact->_sa_handler);
        __put_user(k->sa_flags, &oact->sa_flags);
#if !defined(TARGET_MIPS)
        __put_user(k->sa_restorer, &oact->sa_restorer);
#endif
        /* Not swapped.  */
        oact->sa_mask = k->sa_mask;
    }
    if (act) {
        /* FIXME: This is not threadsafe.  */
        __get_user(k->_sa_handler, &act->_sa_handler);
        __get_user(k->sa_flags, &act->sa_flags);
#if !defined(TARGET_MIPS)
        __get_user(k->sa_restorer, &act->sa_restorer);
#endif
        /* To be swapped in target_to_host_sigset.  */
        k->sa_mask = act->sa_mask;

        /* we update the host linux signal state */
        host_sig = target_to_host_signal(sig);
        if (host_sig != SIGSEGV && host_sig != SIGBUS) {
            sigfillset(&act1.sa_mask);
            act1.sa_flags = SA_SIGINFO;
            if (k->sa_flags & TARGET_SA_RESTART)
                act1.sa_flags |= SA_RESTART;
            /* NOTE: it is important to update the host kernel signal
               ignore state to avoid getting unexpected interrupted
               syscalls */
            if (k->_sa_handler == TARGET_SIG_IGN) {
                act1.sa_sigaction = (void *)SIG_IGN;
            } else if (k->_sa_handler == TARGET_SIG_DFL) {
                if (fatal_signal (sig))
                    act1.sa_sigaction = host_signal_handler;
                else
                    act1.sa_sigaction = (void *)SIG_DFL;
            } else {
                act1.sa_sigaction = host_signal_handler;
            }
            ret = sigaction(host_sig, &act1, NULL);
        }
    }
    return ret;
}

#if defined(TARGET_I386) && TARGET_ABI_BITS == 32

/* from the Linux kernel */

struct target_fpreg {
        uint16_t significand[4];
        uint16_t exponent;
};

struct target_fpxreg {
        uint16_t significand[4];
        uint16_t exponent;
        uint16_t padding[3];
};

struct target_xmmreg {
        abi_ulong element[4];
};

struct target_fpstate {
        /* Regular FPU environment */
        abi_ulong       cw;
        abi_ulong       sw;
        abi_ulong       tag;
        abi_ulong       ipoff;
        abi_ulong       cssel;
        abi_ulong       dataoff;
        abi_ulong       datasel;
        struct target_fpreg     _st[8];
        uint16_t        status;
        uint16_t        magic;          /* 0xffff = regular FPU data only */

        /* FXSR FPU environment */
        abi_ulong       _fxsr_env[6];   /* FXSR FPU env is ignored */
        abi_ulong       mxcsr;
        abi_ulong       reserved;
        struct target_fpxreg    _fxsr_st[8];    /* FXSR FPU reg data is ignored */
        struct target_xmmreg    _xmm[8];
        abi_ulong       padding[56];
};

#define X86_FXSR_MAGIC          0x0000

struct target_sigcontext {
        uint16_t gs, __gsh;
        uint16_t fs, __fsh;
        uint16_t es, __esh;
        uint16_t ds, __dsh;
        abi_ulong edi;
        abi_ulong esi;
        abi_ulong ebp;
        abi_ulong esp;
        abi_ulong ebx;
        abi_ulong edx;
        abi_ulong ecx;
        abi_ulong eax;
        abi_ulong trapno;
        abi_ulong err;
        abi_ulong eip;
        uint16_t cs, __csh;
        abi_ulong eflags;
        abi_ulong esp_at_signal;
        uint16_t ss, __ssh;
        abi_ulong fpstate; /* pointer */
        abi_ulong oldmask;
        abi_ulong cr2;
};

struct target_ucontext {
        abi_ulong         tuc_flags;
        abi_ulong         tuc_link;
        target_stack_t    tuc_stack;
        struct target_sigcontext tuc_mcontext;
        target_sigset_t   tuc_sigmask;  /* mask last for extensibility */
};

struct sigframe
{
    abi_ulong pretcode;
    int sig;
    struct target_sigcontext sc;
    struct target_fpstate fpstate;
    abi_ulong extramask[TARGET_NSIG_WORDS-1];
    char retcode[8];
};

struct rt_sigframe
{
    abi_ulong pretcode;
    int sig;
    abi_ulong pinfo;
    abi_ulong puc;
    struct target_siginfo info;
    struct target_ucontext uc;
    struct target_fpstate fpstate;
    char retcode[8];
};

/*
 * Set up a signal frame.
 */

/* XXX: save x87 state */
static void setup_sigcontext(struct target_sigcontext *sc,
        struct target_fpstate *fpstate, CPUX86State *env, abi_ulong mask,
        abi_ulong fpstate_addr)
{
    CPUState *cs = CPU(x86_env_get_cpu(env));
    uint16_t magic;

        /* already locked in setup_frame() */
    __put_user(env->segs[R_GS].selector, (unsigned int *)&sc->gs);
    __put_user(env->segs[R_FS].selector, (unsigned int *)&sc->fs);
    __put_user(env->segs[R_ES].selector, (unsigned int *)&sc->es);
    __put_user(env->segs[R_DS].selector, (unsigned int *)&sc->ds);
    __put_user(env->regs[R_EDI], &sc->edi);
    __put_user(env->regs[R_ESI], &sc->esi);
    __put_user(env->regs[R_EBP], &sc->ebp);
    __put_user(env->regs[R_ESP], &sc->esp);
    __put_user(env->regs[R_EBX], &sc->ebx);
    __put_user(env->regs[R_EDX], &sc->edx);
    __put_user(env->regs[R_ECX], &sc->ecx);
    __put_user(env->regs[R_EAX], &sc->eax);
    __put_user(cs->exception_index, &sc->trapno);
    __put_user(env->error_code, &sc->err);
    __put_user(env->eip, &sc->eip);
    __put_user(env->segs[R_CS].selector, (unsigned int *)&sc->cs);
    __put_user(env->eflags, &sc->eflags);
    __put_user(env->regs[R_ESP], &sc->esp_at_signal);
    __put_user(env->segs[R_SS].selector, (unsigned int *)&sc->ss);

        cpu_x86_fsave(env, fpstate_addr, 1);
        fpstate->status = fpstate->sw;
        magic = 0xffff;
    __put_user(magic, &fpstate->magic);
    __put_user(fpstate_addr, &sc->fpstate);

        /* non-iBCS2 extensions.. */
    __put_user(mask, &sc->oldmask);
    __put_user(env->cr[2], &sc->cr2);
}

/*
 * Determine which stack to use..
 */

static inline abi_ulong
get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t frame_size)
{
        unsigned long esp;

        /* Default to using normal stack */
        esp = env->regs[R_ESP];
        /* This is the X/Open sanctioned signal stack switching.  */
        if (ka->sa_flags & TARGET_SA_ONSTACK) {
            if (sas_ss_flags(esp) == 0)
                esp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
        }

        /* This is the legacy signal stack switching. */
        else
        if ((env->segs[R_SS].selector & 0xffff) != __USER_DS &&
            !(ka->sa_flags & TARGET_SA_RESTORER) &&
            ka->sa_restorer) {
            esp = (unsigned long) ka->sa_restorer;
        }
        return (esp - frame_size) & -8ul;
}

/* compare linux/arch/i386/kernel/signal.c:setup_frame() */
static void setup_frame(int sig, struct target_sigaction *ka,
                        target_sigset_t *set, CPUX86State *env)
{
        abi_ulong frame_addr;
        struct sigframe *frame;
        int i;

        frame_addr = get_sigframe(ka, env, sizeof(*frame));
        trace_user_setup_frame(env, frame_addr);

        if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
                goto give_sigsegv;

    __put_user(sig, &frame->sig);

        setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
                         frame_addr + offsetof(struct sigframe, fpstate));

    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
        __put_user(set->sig[i], &frame->extramask[i - 1]);
    }

        /* Set up to return from userspace.  If provided, use a stub
           already in userspace.  */
        if (ka->sa_flags & TARGET_SA_RESTORER) {
        __put_user(ka->sa_restorer, &frame->pretcode);
        } else {
                uint16_t val16;
                abi_ulong retcode_addr;
                retcode_addr = frame_addr + offsetof(struct sigframe, retcode);
        __put_user(retcode_addr, &frame->pretcode);
                /* This is popl %eax ; movl $,%eax ; int $0x80 */
                val16 = 0xb858;
        __put_user(val16, (uint16_t *)(frame->retcode+0));
        __put_user(TARGET_NR_sigreturn, (int *)(frame->retcode+2));
                val16 = 0x80cd;
        __put_user(val16, (uint16_t *)(frame->retcode+6));
        }


        /* Set up registers for signal handler */
        env->regs[R_ESP] = frame_addr;
        env->eip = ka->_sa_handler;

        cpu_x86_load_seg(env, R_DS, __USER_DS);
        cpu_x86_load_seg(env, R_ES, __USER_DS);
        cpu_x86_load_seg(env, R_SS, __USER_DS);
        cpu_x86_load_seg(env, R_CS, __USER_CS);
        env->eflags &= ~TF_MASK;

        unlock_user_struct(frame, frame_addr, 1);

        return;

give_sigsegv:
        if (sig == TARGET_SIGSEGV)
                ka->_sa_handler = TARGET_SIG_DFL;
        force_sig(TARGET_SIGSEGV /* , current */);
}

/* compare linux/arch/i386/kernel/signal.c:setup_rt_frame() */
static void setup_rt_frame(int sig, struct target_sigaction *ka,
                           target_siginfo_t *info,
                           target_sigset_t *set, CPUX86State *env)
{
        abi_ulong frame_addr, addr;
        struct rt_sigframe *frame;
        int i;

        frame_addr = get_sigframe(ka, env, sizeof(*frame));
        trace_user_setup_rt_frame(env, frame_addr);

        if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
                goto give_sigsegv;

    __put_user(sig, &frame->sig);
        addr = frame_addr + offsetof(struct rt_sigframe, info);
    __put_user(addr, &frame->pinfo);
        addr = frame_addr + offsetof(struct rt_sigframe, uc);
    __put_user(addr, &frame->puc);
    tswap_siginfo(&frame->info, info);

        /* Create the ucontext.  */
    __put_user(0, &frame->uc.tuc_flags);
    __put_user(0, &frame->uc.tuc_link);
    __put_user(target_sigaltstack_used.ss_sp, &frame->uc.tuc_stack.ss_sp);
    __put_user(sas_ss_flags(get_sp_from_cpustate(env)),
               &frame->uc.tuc_stack.ss_flags);
    __put_user(target_sigaltstack_used.ss_size,
               &frame->uc.tuc_stack.ss_size);
    setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
            set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));

    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
        __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
    }

        /* Set up to return from userspace.  If provided, use a stub
           already in userspace.  */
        if (ka->sa_flags & TARGET_SA_RESTORER) {
        __put_user(ka->sa_restorer, &frame->pretcode);
        } else {
                uint16_t val16;
                addr = frame_addr + offsetof(struct rt_sigframe, retcode);
        __put_user(addr, &frame->pretcode);
                /* This is movl $,%eax ; int $0x80 */
        __put_user(0xb8, (char *)(frame->retcode+0));
        __put_user(TARGET_NR_rt_sigreturn, (int *)(frame->retcode+1));
                val16 = 0x80cd;
        __put_user(val16, (uint16_t *)(frame->retcode+5));

        }

        /* Set up registers for signal handler */
        env->regs[R_ESP] = frame_addr;
        env->eip = ka->_sa_handler;

        cpu_x86_load_seg(env, R_DS, __USER_DS);
        cpu_x86_load_seg(env, R_ES, __USER_DS);
        cpu_x86_load_seg(env, R_SS, __USER_DS);
        cpu_x86_load_seg(env, R_CS, __USER_CS);
        env->eflags &= ~TF_MASK;

        unlock_user_struct(frame, frame_addr, 1);

        return;

give_sigsegv:
        if (sig == TARGET_SIGSEGV)
                ka->_sa_handler = TARGET_SIG_DFL;
        force_sig(TARGET_SIGSEGV /* , current */);
}

static int
restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc, int *peax)
{
        unsigned int err = 0;
        abi_ulong fpstate_addr;
        unsigned int tmpflags;

        cpu_x86_load_seg(env, R_GS, tswap16(sc->gs));
        cpu_x86_load_seg(env, R_FS, tswap16(sc->fs));
        cpu_x86_load_seg(env, R_ES, tswap16(sc->es));
        cpu_x86_load_seg(env, R_DS, tswap16(sc->ds));

        env->regs[R_EDI] = tswapl(sc->edi);
        env->regs[R_ESI] = tswapl(sc->esi);
        env->regs[R_EBP] = tswapl(sc->ebp);
        env->regs[R_ESP] = tswapl(sc->esp);
        env->regs[R_EBX] = tswapl(sc->ebx);
        env->regs[R_EDX] = tswapl(sc->edx);
        env->regs[R_ECX] = tswapl(sc->ecx);
        env->eip = tswapl(sc->eip);

        cpu_x86_load_seg(env, R_CS, lduw_p(&sc->cs) | 3);
        cpu_x86_load_seg(env, R_SS, lduw_p(&sc->ss) | 3);

        tmpflags = tswapl(sc->eflags);
        env->eflags = (env->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
        //              regs->orig_eax = -1;            /* disable syscall checks */

        fpstate_addr = tswapl(sc->fpstate);
        if (fpstate_addr != 0) {
                if (!access_ok(VERIFY_READ, fpstate_addr, 
                               sizeof(struct target_fpstate)))
                        goto badframe;
                cpu_x86_frstor(env, fpstate_addr, 1);
        }

        *peax = tswapl(sc->eax);
        return err;
badframe:
        return 1;
}

long do_sigreturn(CPUX86State *env)
{
    struct sigframe *frame;
    abi_ulong frame_addr = env->regs[R_ESP] - 8;
    target_sigset_t target_set;
    sigset_t set;
    int eax, i;

    trace_user_do_sigreturn(env, frame_addr);
    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
        goto badframe;
    /* set blocked signals */
    __get_user(target_set.sig[0], &frame->sc.oldmask);
    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
        __get_user(target_set.sig[i], &frame->extramask[i - 1]);
    }

    target_to_host_sigset_internal(&set, &target_set);
    do_sigprocmask(SIG_SETMASK, &set, NULL);

    /* restore registers */
    if (restore_sigcontext(env, &frame->sc, &eax))
        goto badframe;
    unlock_user_struct(frame, frame_addr, 0);
    return eax;

badframe:
    unlock_user_struct(frame, frame_addr, 0);
    force_sig(TARGET_SIGSEGV);
    return 0;
}

long do_rt_sigreturn(CPUX86State *env)
{
        abi_ulong frame_addr;
        struct rt_sigframe *frame;
        sigset_t set;
        int eax;

        frame_addr = env->regs[R_ESP] - 4;
        trace_user_do_rt_sigreturn(env, frame_addr);
        if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
                goto badframe;
        target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
        do_sigprocmask(SIG_SETMASK, &set, NULL);

        if (restore_sigcontext(env, &frame->uc.tuc_mcontext, &eax))
                goto badframe;

        if (do_sigaltstack(frame_addr + offsetof(struct rt_sigframe, uc.tuc_stack), 0, 
                           get_sp_from_cpustate(env)) == -EFAULT)
                goto badframe;

        unlock_user_struct(frame, frame_addr, 0);
        return eax;

badframe:
        unlock_user_struct(frame, frame_addr, 0);
        force_sig(TARGET_SIGSEGV);
        return 0;
}

#elif defined(TARGET_AARCH64)

struct target_sigcontext {
    uint64_t fault_address;
    /* AArch64 registers */
    uint64_t regs[31];
    uint64_t sp;
    uint64_t pc;
    uint64_t pstate;
    /* 4K reserved for FP/SIMD state and future expansion */
    char __reserved[4096] __attribute__((__aligned__(16)));
};

struct target_ucontext {
    abi_ulong tuc_flags;
    abi_ulong tuc_link;
    target_stack_t tuc_stack;
    target_sigset_t tuc_sigmask;
    /* glibc uses a 1024-bit sigset_t */
    char __unused[1024 / 8 - sizeof(target_sigset_t)];
    /* last for future expansion */
    struct target_sigcontext tuc_mcontext;
};

/*
 * Header to be used at the beginning of structures extending the user
 * context. Such structures must be placed after the rt_sigframe on the stack
 * and be 16-byte aligned. The last structure must be a dummy one with the
 * magic and size set to 0.
 */
struct target_aarch64_ctx {
    uint32_t magic;
    uint32_t size;
};

#define TARGET_FPSIMD_MAGIC 0x46508001

struct target_fpsimd_context {
    struct target_aarch64_ctx head;
    uint32_t fpsr;
    uint32_t fpcr;
    uint64_t vregs[32 * 2]; /* really uint128_t vregs[32] */
};

/*
 * Auxiliary context saved in the sigcontext.__reserved array. Not exported to
 * user space as it will change with the addition of new context. User space
 * should check the magic/size information.
 */
struct target_aux_context {
    struct target_fpsimd_context fpsimd;
    /* additional context to be added before "end" */
    struct target_aarch64_ctx end;
};

struct target_rt_sigframe {
    struct target_siginfo info;
    struct target_ucontext uc;
    uint64_t fp;
    uint64_t lr;
    uint32_t tramp[2];
};

static int target_setup_sigframe(struct target_rt_sigframe *sf,
                                 CPUARMState *env, target_sigset_t *set)
{
    int i;
    struct target_aux_context *aux =
        (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;

    /* set up the stack frame for unwinding */
    __put_user(env->xregs[29], &sf->fp);
    __put_user(env->xregs[30], &sf->lr);

    for (i = 0; i < 31; i++) {
        __put_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
    }
    __put_user(env->xregs[31], &sf->uc.tuc_mcontext.sp);
    __put_user(env->pc, &sf->uc.tuc_mcontext.pc);
    __put_user(pstate_read(env), &sf->uc.tuc_mcontext.pstate);

    __put_user(env->exception.vaddress, &sf->uc.tuc_mcontext.fault_address);

    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
        __put_user(set->sig[i], &sf->uc.tuc_sigmask.sig[i]);
    }

    for (i = 0; i < 32; i++) {
#ifdef TARGET_WORDS_BIGENDIAN
        __put_user(env->vfp.regs[i * 2], &aux->fpsimd.vregs[i * 2 + 1]);
        __put_user(env->vfp.regs[i * 2 + 1], &aux->fpsimd.vregs[i * 2]);
#else
        __put_user(env->vfp.regs[i * 2], &aux->fpsimd.vregs[i * 2]);
        __put_user(env->vfp.regs[i * 2 + 1], &aux->fpsimd.vregs[i * 2 + 1]);
#endif
    }
    __put_user(vfp_get_fpsr(env), &aux->fpsimd.fpsr);
    __put_user(vfp_get_fpcr(env), &aux->fpsimd.fpcr);
    __put_user(TARGET_FPSIMD_MAGIC, &aux->fpsimd.head.magic);
    __put_user(sizeof(struct target_fpsimd_context),
            &aux->fpsimd.head.size);

    /* set the "end" magic */
    __put_user(0, &aux->end.magic);
    __put_user(0, &aux->end.size);

    return 0;
}

static int target_restore_sigframe(CPUARMState *env,
                                   struct target_rt_sigframe *sf)
{
    sigset_t set;
    int i;
    struct target_aux_context *aux =
        (struct target_aux_context *)sf->uc.tuc_mcontext.__reserved;
    uint32_t magic, size, fpsr, fpcr;
    uint64_t pstate;

    target_to_host_sigset(&set, &sf->uc.tuc_sigmask);
    do_sigprocmask(SIG_SETMASK, &set, NULL);

    for (i = 0; i < 31; i++) {
        __get_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
    }

    __get_user(env->xregs[31], &sf->uc.tuc_mcontext.sp);
    __get_user(env->pc, &sf->uc.tuc_mcontext.pc);
    __get_user(pstate, &sf->uc.tuc_mcontext.pstate);
    pstate_write(env, pstate);

    __get_user(magic, &aux->fpsimd.head.magic);
    __get_user(size, &aux->fpsimd.head.size);

    if (magic != TARGET_FPSIMD_MAGIC
        || size != sizeof(struct target_fpsimd_context)) {
        return 1;
    }

    for (i = 0; i < 32; i++) {
#ifdef TARGET_WORDS_BIGENDIAN
        __get_user(env->vfp.regs[i * 2], &aux->fpsimd.vregs[i * 2 + 1]);
        __get_user(env->vfp.regs[i * 2 + 1], &aux->fpsimd.vregs[i * 2]);
#else
        __get_user(env->vfp.regs[i * 2], &aux->fpsimd.vregs[i * 2]);
        __get_user(env->vfp.regs[i * 2 + 1], &aux->fpsimd.vregs[i * 2 + 1]);
#endif
    }
    __get_user(fpsr, &aux->fpsimd.fpsr);
    vfp_set_fpsr(env, fpsr);
    __get_user(fpcr, &aux->fpsimd.fpcr);
    vfp_set_fpcr(env, fpcr);

    return 0;
}

static abi_ulong get_sigframe(struct target_sigaction *ka, CPUARMState *env)
{
    abi_ulong sp;

    sp = env->xregs[31];

    /*
     * This is the X/Open sanctioned signal stack switching.
     */
    if ((ka->sa_flags & TARGET_SA_ONSTACK) && !sas_ss_flags(sp)) {
        sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
    }

    sp = (sp - sizeof(struct target_rt_sigframe)) & ~15;

    return sp;
}

static void target_setup_frame(int usig, struct target_sigaction *ka,
                               target_siginfo_t *info, target_sigset_t *set,
                               CPUARMState *env)
{
    struct target_rt_sigframe *frame;
    abi_ulong frame_addr, return_addr;

    frame_addr = get_sigframe(ka, env);
    trace_user_setup_frame(env, frame_addr);
    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
        goto give_sigsegv;
    }

    __put_user(0, &frame->uc.tuc_flags);
    __put_user(0, &frame->uc.tuc_link);

    __put_user(target_sigaltstack_used.ss_sp,
                      &frame->uc.tuc_stack.ss_sp);
    __put_user(sas_ss_flags(env->xregs[31]),
                      &frame->uc.tuc_stack.ss_flags);
    __put_user(target_sigaltstack_used.ss_size,
                      &frame->uc.tuc_stack.ss_size);
    target_setup_sigframe(frame, env, set);
    if (ka->sa_flags & TARGET_SA_RESTORER) {
        return_addr = ka->sa_restorer;
    } else {
        /* mov x8,#__NR_rt_sigreturn; svc #0 */
        __put_user(0xd2801168, &frame->tramp[0]);
        __put_user(0xd4000001, &frame->tramp[1]);
        return_addr = frame_addr + offsetof(struct target_rt_sigframe, tramp);
    }
    env->xregs[0] = usig;
    env->xregs[31] = frame_addr;
    env->xregs[29] = env->xregs[31] + offsetof(struct target_rt_sigframe, fp);
    env->pc = ka->_sa_handler;
    env->xregs[30] = return_addr;
    if (info) {
        tswap_siginfo(&frame->info, info);
        env->xregs[1] = frame_addr + offsetof(struct target_rt_sigframe, info);
        env->xregs[2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
    }

    unlock_user_struct(frame, frame_addr, 1);
    return;

 give_sigsegv:
    unlock_user_struct(frame, frame_addr, 1);
    force_sig(TARGET_SIGSEGV);
}

static void setup_rt_frame(int sig, struct target_sigaction *ka,
                           target_siginfo_t *info, target_sigset_t *set,
                           CPUARMState *env)
{
    target_setup_frame(sig, ka, info, set, env);
}

static void setup_frame(int sig, struct target_sigaction *ka,
                        target_sigset_t *set, CPUARMState *env)
{
    target_setup_frame(sig, ka, 0, set, env);
}

long do_rt_sigreturn(CPUARMState *env)
{
    struct target_rt_sigframe *frame = NULL;
    abi_ulong frame_addr = env->xregs[31];

    trace_user_do_rt_sigreturn(env, frame_addr);
    if (frame_addr & 15) {
        goto badframe;
    }

    if  (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
        goto badframe;
    }

    if (target_restore_sigframe(env, frame)) {
        goto badframe;
    }

    if (do_sigaltstack(frame_addr +
            offsetof(struct target_rt_sigframe, uc.tuc_stack),
            0, get_sp_from_cpustate(env)) == -EFAULT) {
        goto badframe;
    }

    unlock_user_struct(frame, frame_addr, 0);
    return env->xregs[0];

 badframe:
    unlock_user_struct(frame, frame_addr, 0);
    force_sig(TARGET_SIGSEGV);
    return 0;
}

long do_sigreturn(CPUARMState *env)
{
    return do_rt_sigreturn(env);
}

#elif defined(TARGET_ARM)

struct target_sigcontext {
        abi_ulong trap_no;
        abi_ulong error_code;
        abi_ulong oldmask;
        abi_ulong arm_r0;
        abi_ulong arm_r1;
        abi_ulong arm_r2;
        abi_ulong arm_r3;
        abi_ulong arm_r4;
        abi_ulong arm_r5;
        abi_ulong arm_r6;
        abi_ulong arm_r7;
        abi_ulong arm_r8;
        abi_ulong arm_r9;
        abi_ulong arm_r10;
        abi_ulong arm_fp;
        abi_ulong arm_ip;
        abi_ulong arm_sp;
        abi_ulong arm_lr;
        abi_ulong arm_pc;
        abi_ulong arm_cpsr;
        abi_ulong fault_address;
};

struct target_ucontext_v1 {
    abi_ulong tuc_flags;
    abi_ulong tuc_link;
    target_stack_t tuc_stack;
    struct target_sigcontext tuc_mcontext;
    target_sigset_t  tuc_sigmask;       /* mask last for extensibility */
};

struct target_ucontext_v2 {
    abi_ulong tuc_flags;
    abi_ulong tuc_link;
    target_stack_t tuc_stack;
    struct target_sigcontext tuc_mcontext;
    target_sigset_t  tuc_sigmask;       /* mask last for extensibility */
    char __unused[128 - sizeof(target_sigset_t)];
    abi_ulong tuc_regspace[128] __attribute__((__aligned__(8)));
};

struct target_user_vfp {
    uint64_t fpregs[32];
    abi_ulong fpscr;
};

struct target_user_vfp_exc {
    abi_ulong fpexc;
    abi_ulong fpinst;
    abi_ulong fpinst2;
};

struct target_vfp_sigframe {
    abi_ulong magic;
    abi_ulong size;
    struct target_user_vfp ufp;
    struct target_user_vfp_exc ufp_exc;
} __attribute__((__aligned__(8)));

struct target_iwmmxt_sigframe {
    abi_ulong magic;
    abi_ulong size;
    uint64_t regs[16];
    /* Note that not all the coprocessor control registers are stored here */
    uint32_t wcssf;
    uint32_t wcasf;
    uint32_t wcgr0;
    uint32_t wcgr1;
    uint32_t wcgr2;
    uint32_t wcgr3;
} __attribute__((__aligned__(8)));

#define TARGET_VFP_MAGIC 0x56465001
#define TARGET_IWMMXT_MAGIC 0x12ef842a

struct sigframe_v1
{
    struct target_sigcontext sc;
    abi_ulong extramask[TARGET_NSIG_WORDS-1];
    abi_ulong retcode;
};

struct sigframe_v2
{
    struct target_ucontext_v2 uc;
    abi_ulong retcode;
};

struct rt_sigframe_v1
{
    abi_ulong pinfo;
    abi_ulong puc;
    struct target_siginfo info;
    struct target_ucontext_v1 uc;
    abi_ulong retcode;
};

struct rt_sigframe_v2
{
    struct target_siginfo info;
    struct target_ucontext_v2 uc;
    abi_ulong retcode;
};

#define TARGET_CONFIG_CPU_32 1

/*
 * For ARM syscalls, we encode the syscall number into the instruction.
 */
#define SWI_SYS_SIGRETURN       (0xef000000|(TARGET_NR_sigreturn + ARM_SYSCALL_BASE))
#define SWI_SYS_RT_SIGRETURN    (0xef000000|(TARGET_NR_rt_sigreturn + ARM_SYSCALL_BASE))

/*
 * For Thumb syscalls, we pass the syscall number via r7.  We therefore
 * need two 16-bit instructions.
 */
#define SWI_THUMB_SIGRETURN     (0xdf00 << 16 | 0x2700 | (TARGET_NR_sigreturn))
#define SWI_THUMB_RT_SIGRETURN  (0xdf00 << 16 | 0x2700 | (TARGET_NR_rt_sigreturn))

static const abi_ulong retcodes[4] = {
        SWI_SYS_SIGRETURN,      SWI_THUMB_SIGRETURN,
        SWI_SYS_RT_SIGRETURN,   SWI_THUMB_RT_SIGRETURN
};


static inline int valid_user_regs(CPUARMState *regs)
{
    return 1;
}

static void
setup_sigcontext(struct target_sigcontext *sc, /*struct _fpstate *fpstate,*/
                 CPUARMState *env, abi_ulong mask)
{
    __put_user(env->regs[0], &sc->arm_r0);
    __put_user(env->regs[1], &sc->arm_r1);
    __put_user(env->regs[2], &sc->arm_r2);
    __put_user(env->regs[3], &sc->arm_r3);
    __put_user(env->regs[4], &sc->arm_r4);
    __put_user(env->regs[5], &sc->arm_r5);
    __put_user(env->regs[6], &sc->arm_r6);
    __put_user(env->regs[7], &sc->arm_r7);
    __put_user(env->regs[8], &sc->arm_r8);
    __put_user(env->regs[9], &sc->arm_r9);
    __put_user(env->regs[10], &sc->arm_r10);
    __put_user(env->regs[11], &sc->arm_fp);
    __put_user(env->regs[12], &sc->arm_ip);
    __put_user(env->regs[13], &sc->arm_sp);
    __put_user(env->regs[14], &sc->arm_lr);
    __put_user(env->regs[15], &sc->arm_pc);
#ifdef TARGET_CONFIG_CPU_32
    __put_user(cpsr_read(env), &sc->arm_cpsr);
#endif

    __put_user(/* current->thread.trap_no */ 0, &sc->trap_no);
    __put_user(/* current->thread.error_code */ 0, &sc->error_code);
    __put_user(/* current->thread.address */ 0, &sc->fault_address);
    __put_user(mask, &sc->oldmask);
}

static inline abi_ulong
get_sigframe(struct target_sigaction *ka, CPUARMState *regs, int framesize)
{
    unsigned long sp = regs->regs[13];

    /*
     * This is the X/Open sanctioned signal stack switching.
     */
    if ((ka->sa_flags & TARGET_SA_ONSTACK) && !sas_ss_flags(sp)) {
        sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
    }
    /*
     * ATPCS B01 mandates 8-byte alignment
     */
    return (sp - framesize) & ~7;
}

static void
setup_return(CPUARMState *env, struct target_sigaction *ka,
             abi_ulong *rc, abi_ulong frame_addr, int usig, abi_ulong rc_addr)
{
    abi_ulong handler = ka->_sa_handler;
    abi_ulong retcode;
    int thumb = handler & 1;
    uint32_t cpsr = cpsr_read(env);

    cpsr &= ~CPSR_IT;
    if (thumb) {
        cpsr |= CPSR_T;
    } else {
        cpsr &= ~CPSR_T;
    }

    if (ka->sa_flags & TARGET_SA_RESTORER) {
        retcode = ka->sa_restorer;
    } else {
        unsigned int idx = thumb;

        if (ka->sa_flags & TARGET_SA_SIGINFO) {
            idx += 2;
        }

        __put_user(retcodes[idx], rc);

        retcode = rc_addr + thumb;
    }

    env->regs[0] = usig;
    env->regs[13] = frame_addr;
    env->regs[14] = retcode;
    env->regs[15] = handler & (thumb ? ~1 : ~3);
    cpsr_write(env, cpsr, CPSR_IT | CPSR_T, CPSRWriteByInstr);
}

static abi_ulong *setup_sigframe_v2_vfp(abi_ulong *regspace, CPUARMState *env)
{
    int i;
    struct target_vfp_sigframe *vfpframe;
    vfpframe = (struct target_vfp_sigframe *)regspace;
    __put_user(TARGET_VFP_MAGIC, &vfpframe->magic);
    __put_user(sizeof(*vfpframe), &vfpframe->size);
    for (i = 0; i < 32; i++) {
        __put_user(float64_val(env->vfp.regs[i]), &vfpframe->ufp.fpregs[i]);
    }
    __put_user(vfp_get_fpscr(env), &vfpframe->ufp.fpscr);
    __put_user(env->vfp.xregs[ARM_VFP_FPEXC], &vfpframe->ufp_exc.fpexc);
    __put_user(env->vfp.xregs[ARM_VFP_FPINST], &vfpframe->ufp_exc.fpinst);
    __put_user(env->vfp.xregs[ARM_VFP_FPINST2], &vfpframe->ufp_exc.fpinst2);
    return (abi_ulong*)(vfpframe+1);
}

static abi_ulong *setup_sigframe_v2_iwmmxt(abi_ulong *regspace,
                                           CPUARMState *env)
{
    int i;
    struct target_iwmmxt_sigframe *iwmmxtframe;
    iwmmxtframe = (struct target_iwmmxt_sigframe *)regspace;
    __put_user(TARGET_IWMMXT_MAGIC, &iwmmxtframe->magic);
    __put_user(sizeof(*iwmmxtframe), &iwmmxtframe->size);
    for (i = 0; i < 16; i++) {
        __put_user(env->iwmmxt.regs[i], &iwmmxtframe->regs[i]);
    }
    __put_user(env->vfp.xregs[ARM_IWMMXT_wCSSF], &iwmmxtframe->wcssf);
    __put_user(env->vfp.xregs[ARM_IWMMXT_wCASF], &iwmmxtframe->wcssf);
    __put_user(env->vfp.xregs[ARM_IWMMXT_wCGR0], &iwmmxtframe->wcgr0);
    __put_user(env->vfp.xregs[ARM_IWMMXT_wCGR1], &iwmmxtframe->wcgr1);
    __put_user(env->vfp.xregs[ARM_IWMMXT_wCGR2], &iwmmxtframe->wcgr2);
    __put_user(env->vfp.xregs[ARM_IWMMXT_wCGR3], &iwmmxtframe->wcgr3);
    return (abi_ulong*)(iwmmxtframe+1);
}

static void setup_sigframe_v2(struct target_ucontext_v2 *uc,
                              target_sigset_t *set, CPUARMState *env)
{
    struct target_sigaltstack stack;
    int i;
    abi_ulong *regspace;

    /* Clear all the bits of the ucontext we don't use.  */
    memset(uc, 0, offsetof(struct target_ucontext_v2, tuc_mcontext));

    memset(&stack, 0, sizeof(stack));
    __put_user(target_sigaltstack_used.ss_sp, &stack.ss_sp);
    __put_user(target_sigaltstack_used.ss_size, &stack.ss_size);
    __put_user(sas_ss_flags(get_sp_from_cpustate(env)), &stack.ss_flags);
    memcpy(&uc->tuc_stack, &stack, sizeof(stack));

    setup_sigcontext(&uc->tuc_mcontext, env, set->sig[0]);
    /* Save coprocessor signal frame.  */
    regspace = uc->tuc_regspace;
    if (arm_feature(env, ARM_FEATURE_VFP)) {
        regspace = setup_sigframe_v2_vfp(regspace, env);
    }
    if (arm_feature(env, ARM_FEATURE_IWMMXT)) {
        regspace = setup_sigframe_v2_iwmmxt(regspace, env);
    }

    /* Write terminating magic word */
    __put_user(0, regspace);

    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
        __put_user(set->sig[i], &uc->tuc_sigmask.sig[i]);
    }
}

/* compare linux/arch/arm/kernel/signal.c:setup_frame() */
static void setup_frame_v1(int usig, struct target_sigaction *ka,
                           target_sigset_t *set, CPUARMState *regs)
{
        struct sigframe_v1 *frame;
        abi_ulong frame_addr = get_sigframe(ka, regs, sizeof(*frame));
        int i;

        trace_user_setup_frame(regs, frame_addr);
        if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
                return;

        setup_sigcontext(&frame->sc, regs, set->sig[0]);

    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
        __put_user(set->sig[i], &frame->extramask[i - 1]);
    }

        setup_return(regs, ka, &frame->retcode, frame_addr, usig,
                     frame_addr + offsetof(struct sigframe_v1, retcode));

        unlock_user_struct(frame, frame_addr, 1);
}

static void setup_frame_v2(int usig, struct target_sigaction *ka,
                           target_sigset_t *set, CPUARMState *regs)
{
        struct sigframe_v2 *frame;
        abi_ulong frame_addr = get_sigframe(ka, regs, sizeof(*frame));

        trace_user_setup_frame(regs, frame_addr);
        if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
                return;

        setup_sigframe_v2(&frame->uc, set, regs);

        setup_return(regs, ka, &frame->retcode, frame_addr, usig,
                     frame_addr + offsetof(struct sigframe_v2, retcode));

        unlock_user_struct(frame, frame_addr, 1);
}

static void setup_frame(int usig, struct target_sigaction *ka,
                        target_sigset_t *set, CPUARMState *regs)
{
    if (get_osversion() >= 0x020612) {
        setup_frame_v2(usig, ka, set, regs);
    } else {
        setup_frame_v1(usig, ka, set, regs);
    }
}

/* compare linux/arch/arm/kernel/signal.c:setup_rt_frame() */
static void setup_rt_frame_v1(int usig, struct target_sigaction *ka,
                              target_siginfo_t *info,
                              target_sigset_t *set, CPUARMState *env)
{
        struct rt_sigframe_v1 *frame;
        abi_ulong frame_addr = get_sigframe(ka, env, sizeof(*frame));
        struct target_sigaltstack stack;
        int i;
        abi_ulong info_addr, uc_addr;

        trace_user_setup_rt_frame(env, frame_addr);
        if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
            return /* 1 */;

        info_addr = frame_addr + offsetof(struct rt_sigframe_v1, info);
        __put_user(info_addr, &frame->pinfo);
        uc_addr = frame_addr + offsetof(struct rt_sigframe_v1, uc);
        __put_user(uc_addr, &frame->puc);
        tswap_siginfo(&frame->info, info);

        /* Clear all the bits of the ucontext we don't use.  */
        memset(&frame->uc, 0, offsetof(struct target_ucontext_v1, tuc_mcontext));

        memset(&stack, 0, sizeof(stack));
        __put_user(target_sigaltstack_used.ss_sp, &stack.ss_sp);
        __put_user(target_sigaltstack_used.ss_size, &stack.ss_size);
        __put_user(sas_ss_flags(get_sp_from_cpustate(env)), &stack.ss_flags);
        memcpy(&frame->uc.tuc_stack, &stack, sizeof(stack));

        setup_sigcontext(&frame->uc.tuc_mcontext, env, set->sig[0]);
        for(i = 0; i < TARGET_NSIG_WORDS; i++) {
            __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
        }

        setup_return(env, ka, &frame->retcode, frame_addr, usig,
                     frame_addr + offsetof(struct rt_sigframe_v1, retcode));

        env->regs[1] = info_addr;
        env->regs[2] = uc_addr;

        unlock_user_struct(frame, frame_addr, 1);
}

static void setup_rt_frame_v2(int usig, struct target_sigaction *ka,
                              target_siginfo_t *info,
                              target_sigset_t *set, CPUARMState *env)
{
        struct rt_sigframe_v2 *frame;
        abi_ulong frame_addr = get_sigframe(ka, env, sizeof(*frame));
        abi_ulong info_addr, uc_addr;

        trace_user_setup_rt_frame(env, frame_addr);
        if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
            return /* 1 */;

        info_addr = frame_addr + offsetof(struct rt_sigframe_v2, info);
        uc_addr = frame_addr + offsetof(struct rt_sigframe_v2, uc);
        tswap_siginfo(&frame->info, info);

        setup_sigframe_v2(&frame->uc, set, env);

        setup_return(env, ka, &frame->retcode, frame_addr, usig,
                     frame_addr + offsetof(struct rt_sigframe_v2, retcode));

        env->regs[1] = info_addr;
        env->regs[2] = uc_addr;

        unlock_user_struct(frame, frame_addr, 1);
}

static void setup_rt_frame(int usig, struct target_sigaction *ka,
                           target_siginfo_t *info,
                           target_sigset_t *set, CPUARMState *env)
{
    if (get_osversion() >= 0x020612) {
        setup_rt_frame_v2(usig, ka, info, set, env);
    } else {
        setup_rt_frame_v1(usig, ka, info, set, env);
    }
}

static int
restore_sigcontext(CPUARMState *env, struct target_sigcontext *sc)
{
        int err = 0;
        uint32_t cpsr;

    __get_user(env->regs[0], &sc->arm_r0);
    __get_user(env->regs[1], &sc->arm_r1);
    __get_user(env->regs[2], &sc->arm_r2);
    __get_user(env->regs[3], &sc->arm_r3);
    __get_user(env->regs[4], &sc->arm_r4);
    __get_user(env->regs[5], &sc->arm_r5);
    __get_user(env->regs[6], &sc->arm_r6);
    __get_user(env->regs[7], &sc->arm_r7);
    __get_user(env->regs[8], &sc->arm_r8);
    __get_user(env->regs[9], &sc->arm_r9);
    __get_user(env->regs[10], &sc->arm_r10);
    __get_user(env->regs[11], &sc->arm_fp);
    __get_user(env->regs[12], &sc->arm_ip);
    __get_user(env->regs[13], &sc->arm_sp);
    __get_user(env->regs[14], &sc->arm_lr);
    __get_user(env->regs[15], &sc->arm_pc);
#ifdef TARGET_CONFIG_CPU_32
    __get_user(cpsr, &sc->arm_cpsr);
    cpsr_write(env, cpsr, CPSR_USER | CPSR_EXEC, CPSRWriteByInstr);
#endif

        err |= !valid_user_regs(env);

        return err;
}

static long do_sigreturn_v1(CPUARMState *env)
{
        abi_ulong frame_addr;
        struct sigframe_v1 *frame = NULL;
        target_sigset_t set;
        sigset_t host_set;
        int i;

        /*
         * Since we stacked the signal on a 64-bit boundary,
         * then 'sp' should be word aligned here.  If it's
         * not, then the user is trying to mess with us.
         */
        frame_addr = env->regs[13];
        trace_user_do_sigreturn(env, frame_addr);
        if (frame_addr & 7) {
            goto badframe;
        }

        if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
                goto badframe;

    __get_user(set.sig[0], &frame->sc.oldmask);
    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
        __get_user(set.sig[i], &frame->extramask[i - 1]);
    }

        target_to_host_sigset_internal(&host_set, &set);
        do_sigprocmask(SIG_SETMASK, &host_set, NULL);

        if (restore_sigcontext(env, &frame->sc))
                goto badframe;

#if 0
        /* Send SIGTRAP if we're single-stepping */
        if (ptrace_cancel_bpt(current))
                send_sig(SIGTRAP, current, 1);
#endif
        unlock_user_struct(frame, frame_addr, 0);
        return env->regs[0];

badframe:
        force_sig(TARGET_SIGSEGV /* , current */);
        return 0;
}

static abi_ulong *restore_sigframe_v2_vfp(CPUARMState *env, abi_ulong *regspace)
{
    int i;
    abi_ulong magic, sz;
    uint32_t fpscr, fpexc;
    struct target_vfp_sigframe *vfpframe;
    vfpframe = (struct target_vfp_sigframe *)regspace;

    __get_user(magic, &vfpframe->magic);
    __get_user(sz, &vfpframe->size);
    if (magic != TARGET_VFP_MAGIC || sz != sizeof(*vfpframe)) {
        return 0;
    }
    for (i = 0; i < 32; i++) {
        __get_user(float64_val(env->vfp.regs[i]), &vfpframe->ufp.fpregs[i]);
    }
    __get_user(fpscr, &vfpframe->ufp.fpscr);
    vfp_set_fpscr(env, fpscr);
    __get_user(fpexc, &vfpframe->ufp_exc.fpexc);
    /* Sanitise FPEXC: ensure VFP is enabled, FPINST2 is invalid
     * and the exception flag is cleared
     */
    fpexc |= (1 << 30);
    fpexc &= ~((1 << 31) | (1 << 28));
    env->vfp.xregs[ARM_VFP_FPEXC] = fpexc;
    __get_user(env->vfp.xregs[ARM_VFP_FPINST], &vfpframe->ufp_exc.fpinst);
    __get_user(env->vfp.xregs[ARM_VFP_FPINST2], &vfpframe->ufp_exc.fpinst2);
    return (abi_ulong*)(vfpframe + 1);
}

static abi_ulong *restore_sigframe_v2_iwmmxt(CPUARMState *env,
                                             abi_ulong *regspace)
{
    int i;
    abi_ulong magic, sz;
    struct target_iwmmxt_sigframe *iwmmxtframe;
    iwmmxtframe = (struct target_iwmmxt_sigframe *)regspace;

    __get_user(magic, &iwmmxtframe->magic);
    __get_user(sz, &iwmmxtframe->size);
    if (magic != TARGET_IWMMXT_MAGIC || sz != sizeof(*iwmmxtframe)) {
        return 0;
    }
    for (i = 0; i < 16; i++) {
        __get_user(env->iwmmxt.regs[i], &iwmmxtframe->regs[i]);
    }
    __get_user(env->vfp.xregs[ARM_IWMMXT_wCSSF], &iwmmxtframe->wcssf);
    __get_user(env->vfp.xregs[ARM_IWMMXT_wCASF], &iwmmxtframe->wcssf);
    __get_user(env->vfp.xregs[ARM_IWMMXT_wCGR0], &iwmmxtframe->wcgr0);
    __get_user(env->vfp.xregs[ARM_IWMMXT_wCGR1], &iwmmxtframe->wcgr1);
    __get_user(env->vfp.xregs[ARM_IWMMXT_wCGR2], &iwmmxtframe->wcgr2);
    __get_user(env->vfp.xregs[ARM_IWMMXT_wCGR3], &iwmmxtframe->wcgr3);
    return (abi_ulong*)(iwmmxtframe + 1);
}

static int do_sigframe_return_v2(CPUARMState *env, target_ulong frame_addr,
                                 struct target_ucontext_v2 *uc)
{
    sigset_t host_set;
    abi_ulong *regspace;

    target_to_host_sigset(&host_set, &uc->tuc_sigmask);
    do_sigprocmask(SIG_SETMASK, &host_set, NULL);

    if (restore_sigcontext(env, &uc->tuc_mcontext))
        return 1;

    /* Restore coprocessor signal frame */
    regspace = uc->tuc_regspace;
    if (arm_feature(env, ARM_FEATURE_VFP)) {
        regspace = restore_sigframe_v2_vfp(env, regspace);
        if (!regspace) {
            return 1;
        }
    }
    if (arm_feature(env, ARM_FEATURE_IWMMXT)) {
        regspace = restore_sigframe_v2_iwmmxt(env, regspace);
        if (!regspace) {
            return 1;
        }
    }

    if (do_sigaltstack(frame_addr + offsetof(struct target_ucontext_v2, tuc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT)
        return 1;

#if 0
    /* Send SIGTRAP if we're single-stepping */
    if (ptrace_cancel_bpt(current))
            send_sig(SIGTRAP, current, 1);
#endif

    return 0;
}

static long do_sigreturn_v2(CPUARMState *env)
{
        abi_ulong frame_addr;
        struct sigframe_v2 *frame = NULL;

        /*
         * Since we stacked the signal on a 64-bit boundary,
         * then 'sp' should be word aligned here.  If it's
         * not, then the user is trying to mess with us.
         */
        frame_addr = env->regs[13];
        trace_user_do_sigreturn(env, frame_addr);
        if (frame_addr & 7) {
            goto badframe;
        }

        if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
                goto badframe;

        if (do_sigframe_return_v2(env, frame_addr, &frame->uc))
                goto badframe;

        unlock_user_struct(frame, frame_addr, 0);
        return env->regs[0];

badframe:
        unlock_user_struct(frame, frame_addr, 0);
        force_sig(TARGET_SIGSEGV /* , current */);
        return 0;
}

long do_sigreturn(CPUARMState *env)
{
    if (get_osversion() >= 0x020612) {
        return do_sigreturn_v2(env);
    } else {
        return do_sigreturn_v1(env);
    }
}

static long do_rt_sigreturn_v1(CPUARMState *env)
{
        abi_ulong frame_addr;
        struct rt_sigframe_v1 *frame = NULL;
        sigset_t host_set;

        /*
         * Since we stacked the signal on a 64-bit boundary,
         * then 'sp' should be word aligned here.  If it's
         * not, then the user is trying to mess with us.
         */
        frame_addr = env->regs[13];
        trace_user_do_rt_sigreturn(env, frame_addr);
        if (frame_addr & 7) {
            goto badframe;
        }

        if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
                goto badframe;

        target_to_host_sigset(&host_set, &frame->uc.tuc_sigmask);
        do_sigprocmask(SIG_SETMASK, &host_set, NULL);

        if (restore_sigcontext(env, &frame->uc.tuc_mcontext))
                goto badframe;

        if (do_sigaltstack(frame_addr + offsetof(struct rt_sigframe_v1, uc.tuc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT)
                goto badframe;

#if 0
        /* Send SIGTRAP if we're single-stepping */
        if (ptrace_cancel_bpt(current))
                send_sig(SIGTRAP, current, 1);
#endif
        unlock_user_struct(frame, frame_addr, 0);
        return env->regs[0];

badframe:
        unlock_user_struct(frame, frame_addr, 0);
        force_sig(TARGET_SIGSEGV /* , current */);
        return 0;
}

static long do_rt_sigreturn_v2(CPUARMState *env)
{
        abi_ulong frame_addr;
        struct rt_sigframe_v2 *frame = NULL;

        /*
         * Since we stacked the signal on a 64-bit boundary,
         * then 'sp' should be word aligned here.  If it's
         * not, then the user is trying to mess with us.
         */
        frame_addr = env->regs[13];
        trace_user_do_rt_sigreturn(env, frame_addr);
        if (frame_addr & 7) {
            goto badframe;
        }

        if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
                goto badframe;

        if (do_sigframe_return_v2(env, frame_addr, &frame->uc))
                goto badframe;

        unlock_user_struct(frame, frame_addr, 0);
        return env->regs[0];

badframe:
        unlock_user_struct(frame, frame_addr, 0);
        force_sig(TARGET_SIGSEGV /* , current */);
        return 0;
}

long do_rt_sigreturn(CPUARMState *env)
{
    if (get_osversion() >= 0x020612) {
        return do_rt_sigreturn_v2(env);
    } else {
        return do_rt_sigreturn_v1(env);
    }
}

#elif defined(TARGET_SPARC)

#define __SUNOS_MAXWIN   31

/* This is what SunOS does, so shall I. */
struct target_sigcontext {
        abi_ulong sigc_onstack;      /* state to restore */

        abi_ulong sigc_mask;         /* sigmask to restore */
        abi_ulong sigc_sp;           /* stack pointer */
        abi_ulong sigc_pc;           /* program counter */
        abi_ulong sigc_npc;          /* next program counter */
        abi_ulong sigc_psr;          /* for condition codes etc */
        abi_ulong sigc_g1;           /* User uses these two registers */
        abi_ulong sigc_o0;           /* within the trampoline code. */

        /* Now comes information regarding the users window set
         * at the time of the signal.
         */
        abi_ulong sigc_oswins;       /* outstanding windows */

        /* stack ptrs for each regwin buf */
        char *sigc_spbuf[__SUNOS_MAXWIN];

        /* Windows to restore after signal */
        struct {
                abi_ulong locals[8];
                abi_ulong ins[8];
        } sigc_wbuf[__SUNOS_MAXWIN];
};
/* A Sparc stack frame */
struct sparc_stackf {
        abi_ulong locals[8];
        abi_ulong ins[8];
        /* It's simpler to treat fp and callers_pc as elements of ins[]
         * since we never need to access them ourselves.
         */
        char *structptr;
        abi_ulong xargs[6];
        abi_ulong xxargs[1];
};

typedef struct {
        struct {
                abi_ulong psr;
                abi_ulong pc;
                abi_ulong npc;
                abi_ulong y;
                abi_ulong u_regs[16]; /* globals and ins */
        }               si_regs;
        int             si_mask;
} __siginfo_t;

typedef struct {
        abi_ulong       si_float_regs[32];
        unsigned   long si_fsr;
        unsigned   long si_fpqdepth;
        struct {
                unsigned long *insn_addr;
                unsigned long insn;
        } si_fpqueue [16];
} qemu_siginfo_fpu_t;


struct target_signal_frame {
        struct sparc_stackf     ss;
        __siginfo_t             info;
        abi_ulong               fpu_save;
        abi_ulong               insns[2] __attribute__ ((aligned (8)));
        abi_ulong               extramask[TARGET_NSIG_WORDS - 1];
        abi_ulong               extra_size; /* Should be 0 */
        qemu_siginfo_fpu_t      fpu_state;
};
struct target_rt_signal_frame {
        struct sparc_stackf     ss;
        siginfo_t               info;
        abi_ulong               regs[20];
        sigset_t                mask;
        abi_ulong               fpu_save;
        unsigned int            insns[2];
        stack_t                 stack;
        unsigned int            extra_size; /* Should be 0 */
        qemu_siginfo_fpu_t      fpu_state;
};

#define UREG_O0        16
#define UREG_O6        22
#define UREG_I0        0
#define UREG_I1        1
#define UREG_I2        2
#define UREG_I3        3
#define UREG_I4        4
#define UREG_I5        5
#define UREG_I6        6
#define UREG_I7        7
#define UREG_L0        8
#define UREG_FP        UREG_I6
#define UREG_SP        UREG_O6

static inline abi_ulong get_sigframe(struct target_sigaction *sa, 
                                     CPUSPARCState *env,
                                     unsigned long framesize)
{
        abi_ulong sp;

        sp = env->regwptr[UREG_FP];

        /* This is the X/Open sanctioned signal stack switching.  */
        if (sa->sa_flags & TARGET_SA_ONSTACK) {
            if (!on_sig_stack(sp)
                && !((target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size) & 7))
                sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
        }
        return sp - framesize;
}

static int
setup___siginfo(__siginfo_t *si, CPUSPARCState *env, abi_ulong mask)
{
        int err = 0, i;

    __put_user(env->psr, &si->si_regs.psr);
    __put_user(env->pc, &si->si_regs.pc);
    __put_user(env->npc, &si->si_regs.npc);
    __put_user(env->y, &si->si_regs.y);
        for (i=0; i < 8; i++) {
        __put_user(env->gregs[i], &si->si_regs.u_regs[i]);
        }
        for (i=0; i < 8; i++) {
        __put_user(env->regwptr[UREG_I0 + i], &si->si_regs.u_regs[i+8]);
        }
    __put_user(mask, &si->si_mask);
        return err;
}

#if 0
static int
setup_sigcontext(struct target_sigcontext *sc, /*struct _fpstate *fpstate,*/
                 CPUSPARCState *env, unsigned long mask)
{
        int err = 0;

    __put_user(mask, &sc->sigc_mask);
    __put_user(env->regwptr[UREG_SP], &sc->sigc_sp);
    __put_user(env->pc, &sc->sigc_pc);
    __put_user(env->npc, &sc->sigc_npc);
    __put_user(env->psr, &sc->sigc_psr);
    __put_user(env->gregs[1], &sc->sigc_g1);
    __put_user(env->regwptr[UREG_O0], &sc->sigc_o0);

        return err;
}
#endif
#define NF_ALIGNEDSZ  (((sizeof(struct target_signal_frame) + 7) & (~7)))

static void setup_frame(int sig, struct target_sigaction *ka,
                        target_sigset_t *set, CPUSPARCState *env)
{
        abi_ulong sf_addr;
        struct target_signal_frame *sf;
        int sigframe_size, err, i;

        /* 1. Make sure everything is clean */
        //synchronize_user_stack();

        sigframe_size = NF_ALIGNEDSZ;
        sf_addr = get_sigframe(ka, env, sigframe_size);
        trace_user_setup_frame(env, sf_addr);

        sf = lock_user(VERIFY_WRITE, sf_addr, 
                       sizeof(struct target_signal_frame), 0);
        if (!sf)
                goto sigsegv;
                
#if 0
        if (invalid_frame_pointer(sf, sigframe_size))
                goto sigill_and_return;
#endif
        /* 2. Save the current process state */
        err = setup___siginfo(&sf->info, env, set->sig[0]);
    __put_user(0, &sf->extra_size);

        //save_fpu_state(regs, &sf->fpu_state);
        //__put_user(&sf->fpu_state, &sf->fpu_save);

    __put_user(set->sig[0], &sf->info.si_mask);
        for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
        __put_user(set->sig[i + 1], &sf->extramask[i]);
        }

        for (i = 0; i < 8; i++) {
        __put_user(env->regwptr[i + UREG_L0], &sf->ss.locals[i]);
        }
        for (i = 0; i < 8; i++) {
        __put_user(env->regwptr[i + UREG_I0], &sf->ss.ins[i]);
        }
        if (err)
                goto sigsegv;

        /* 3. signal handler back-trampoline and parameters */
        env->regwptr[UREG_FP] = sf_addr;
        env->regwptr[UREG_I0] = sig;
        env->regwptr[UREG_I1] = sf_addr + 
                offsetof(struct target_signal_frame, info);
        env->regwptr[UREG_I2] = sf_addr + 
                offsetof(struct target_signal_frame, info);

        /* 4. signal handler */
        env->pc = ka->_sa_handler;
        env->npc = (env->pc + 4);
        /* 5. return to kernel instructions */
        if (ka->sa_restorer)
                env->regwptr[UREG_I7] = ka->sa_restorer;
        else {
                uint32_t val32;

                env->regwptr[UREG_I7] = sf_addr + 
                        offsetof(struct target_signal_frame, insns) - 2 * 4;

                /* mov __NR_sigreturn, %g1 */
                val32 = 0x821020d8;
        __put_user(val32, &sf->insns[0]);

                /* t 0x10 */
                val32 = 0x91d02010;
        __put_user(val32, &sf->insns[1]);
                if (err)
                        goto sigsegv;

                /* Flush instruction space. */
                //flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
                //              tb_flush(CPU(sparc_env_get_cpu(env)));
        }
        unlock_user(sf, sf_addr, sizeof(struct target_signal_frame));
        return;
#if 0
sigill_and_return:
        force_sig(TARGET_SIGILL);
#endif
sigsegv:
        unlock_user(sf, sf_addr, sizeof(struct target_signal_frame));
        force_sig(TARGET_SIGSEGV);
}

static void setup_rt_frame(int sig, struct target_sigaction *ka,
                           target_siginfo_t *info,
                           target_sigset_t *set, CPUSPARCState *env)
{
    fprintf(stderr, "setup_rt_frame: not implemented\n");
}

long do_sigreturn(CPUSPARCState *env)
{
        abi_ulong sf_addr;
        struct target_signal_frame *sf;
        uint32_t up_psr, pc, npc;
        target_sigset_t set;
        sigset_t host_set;
        int err=0, i;

        sf_addr = env->regwptr[UREG_FP];
        trace_user_do_sigreturn(env, sf_addr);
        if (!lock_user_struct(VERIFY_READ, sf, sf_addr, 1))
                goto segv_and_exit;

        /* 1. Make sure we are not getting garbage from the user */

        if (sf_addr & 3)
                goto segv_and_exit;

        __get_user(pc,  &sf->info.si_regs.pc);
        __get_user(npc, &sf->info.si_regs.npc);

        if ((pc | npc) & 3)
                goto segv_and_exit;

        /* 2. Restore the state */
        __get_user(up_psr, &sf->info.si_regs.psr);

        /* User can only change condition codes and FPU enabling in %psr. */
        env->psr = (up_psr & (PSR_ICC /* | PSR_EF */))
                  | (env->psr & ~(PSR_ICC /* | PSR_EF */));

        env->pc = pc;
        env->npc = npc;
        __get_user(env->y, &sf->info.si_regs.y);
        for (i=0; i < 8; i++) {
                __get_user(env->gregs[i], &sf->info.si_regs.u_regs[i]);
        }
        for (i=0; i < 8; i++) {
                __get_user(env->regwptr[i + UREG_I0], &sf->info.si_regs.u_regs[i+8]);
        }

        /* FIXME: implement FPU save/restore:
         * __get_user(fpu_save, &sf->fpu_save);
         * if (fpu_save)
         *        err |= restore_fpu_state(env, fpu_save);
         */

        /* This is pretty much atomic, no amount locking would prevent
         * the races which exist anyways.
         */
        __get_user(set.sig[0], &sf->info.si_mask);
        for(i = 1; i < TARGET_NSIG_WORDS; i++) {
            __get_user(set.sig[i], &sf->extramask[i - 1]);
        }

        target_to_host_sigset_internal(&host_set, &set);
        do_sigprocmask(SIG_SETMASK, &host_set, NULL);

        if (err)
                goto segv_and_exit;
        unlock_user_struct(sf, sf_addr, 0);
        return env->regwptr[0];

segv_and_exit:
        unlock_user_struct(sf, sf_addr, 0);
        force_sig(TARGET_SIGSEGV);
}

long do_rt_sigreturn(CPUSPARCState *env)
{
    trace_user_do_rt_sigreturn(env, 0);
    fprintf(stderr, "do_rt_sigreturn: not implemented\n");
    return -TARGET_ENOSYS;
}

#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
#define MC_TSTATE 0
#define MC_PC 1
#define MC_NPC 2
#define MC_Y 3
#define MC_G1 4
#define MC_G2 5
#define MC_G3 6
#define MC_G4 7
#define MC_G5 8
#define MC_G6 9
#define MC_G7 10
#define MC_O0 11
#define MC_O1 12
#define MC_O2 13
#define MC_O3 14
#define MC_O4 15
#define MC_O5 16
#define MC_O6 17
#define MC_O7 18
#define MC_NGREG 19

typedef abi_ulong target_mc_greg_t;
typedef target_mc_greg_t target_mc_gregset_t[MC_NGREG];

struct target_mc_fq {
    abi_ulong *mcfq_addr;
    uint32_t mcfq_insn;
};

struct target_mc_fpu {
    union {
        uint32_t sregs[32];
        uint64_t dregs[32];
        //uint128_t qregs[16];
    } mcfpu_fregs;
    abi_ulong mcfpu_fsr;
    abi_ulong mcfpu_fprs;
    abi_ulong mcfpu_gsr;
    struct target_mc_fq *mcfpu_fq;
    unsigned char mcfpu_qcnt;
    unsigned char mcfpu_qentsz;
    unsigned char mcfpu_enab;
};
typedef struct target_mc_fpu target_mc_fpu_t;

typedef struct {
    target_mc_gregset_t mc_gregs;
    target_mc_greg_t mc_fp;
    target_mc_greg_t mc_i7;
    target_mc_fpu_t mc_fpregs;
} target_mcontext_t;

struct target_ucontext {
    struct target_ucontext *tuc_link;
    abi_ulong tuc_flags;
    target_sigset_t tuc_sigmask;
    target_mcontext_t tuc_mcontext;
};

/* A V9 register window */
struct target_reg_window {
    abi_ulong locals[8];
    abi_ulong ins[8];
};

#define TARGET_STACK_BIAS 2047

/* {set, get}context() needed for 64-bit SparcLinux userland. */
void sparc64_set_context(CPUSPARCState *env)
{
    abi_ulong ucp_addr;
    struct target_ucontext *ucp;
    target_mc_gregset_t *grp;
    abi_ulong pc, npc, tstate;
    abi_ulong fp, i7, w_addr;
    unsigned int i;

    ucp_addr = env->regwptr[UREG_I0];
    if (!lock_user_struct(VERIFY_READ, ucp, ucp_addr, 1))
        goto do_sigsegv;
    grp  = &ucp->tuc_mcontext.mc_gregs;
    __get_user(pc, &((*grp)[MC_PC]));
    __get_user(npc, &((*grp)[MC_NPC]));
    if ((pc | npc) & 3)
        goto do_sigsegv;
    if (env->regwptr[UREG_I1]) {
        target_sigset_t target_set;
        sigset_t set;

        if (TARGET_NSIG_WORDS == 1) {
            __get_user(target_set.sig[0], &ucp->tuc_sigmask.sig[0]);
        } else {
            abi_ulong *src, *dst;
            src = ucp->tuc_sigmask.sig;
            dst = target_set.sig;
            for (i = 0; i < TARGET_NSIG_WORDS; i++, dst++, src++) {
                __get_user(*dst, src);
            }
        }
        target_to_host_sigset_internal(&set, &target_set);
        do_sigprocmask(SIG_SETMASK, &set, NULL);
    }
    env->pc = pc;
    env->npc = npc;
    __get_user(env->y, &((*grp)[MC_Y]));
    __get_user(tstate, &((*grp)[MC_TSTATE]));
    env->asi = (tstate >> 24) & 0xff;
    cpu_put_ccr(env, tstate >> 32);
    cpu_put_cwp64(env, tstate & 0x1f);
    __get_user(env->gregs[1], (&(*grp)[MC_G1]));
    __get_user(env->gregs[2], (&(*grp)[MC_G2]));
    __get_user(env->gregs[3], (&(*grp)[MC_G3]));
    __get_user(env->gregs[4], (&(*grp)[MC_G4]));
    __get_user(env->gregs[5], (&(*grp)[MC_G5]));
    __get_user(env->gregs[6], (&(*grp)[MC_G6]));
    __get_user(env->gregs[7], (&(*grp)[MC_G7]));
    __get_user(env->regwptr[UREG_I0], (&(*grp)[MC_O0]));
    __get_user(env->regwptr[UREG_I1], (&(*grp)[MC_O1]));
    __get_user(env->regwptr[UREG_I2], (&(*grp)[MC_O2]));
    __get_user(env->regwptr[UREG_I3], (&(*grp)[MC_O3]));
    __get_user(env->regwptr[UREG_I4], (&(*grp)[MC_O4]));
    __get_user(env->regwptr[UREG_I5], (&(*grp)[MC_O5]));
    __get_user(env->regwptr[UREG_I6], (&(*grp)[MC_O6]));
    __get_user(env->regwptr[UREG_I7], (&(*grp)[MC_O7]));

    __get_user(fp, &(ucp->tuc_mcontext.mc_fp));
    __get_user(i7, &(ucp->tuc_mcontext.mc_i7));

    w_addr = TARGET_STACK_BIAS+env->regwptr[UREG_I6];
    if (put_user(fp, w_addr + offsetof(struct target_reg_window, ins[6]), 
                 abi_ulong) != 0)
        goto do_sigsegv;
    if (put_user(i7, w_addr + offsetof(struct target_reg_window, ins[7]), 
                 abi_ulong) != 0)
        goto do_sigsegv;
    /* FIXME this does not match how the kernel handles the FPU in
     * its sparc64_set_context implementation. In particular the FPU
     * is only restored if fenab is non-zero in:
     *   __get_user(fenab, &(ucp->tuc_mcontext.mc_fpregs.mcfpu_enab));
     */
    __get_user(env->fprs, &(ucp->tuc_mcontext.mc_fpregs.mcfpu_fprs));
    {
        uint32_t *src = ucp->tuc_mcontext.mc_fpregs.mcfpu_fregs.sregs;
        for (i = 0; i < 64; i++, src++) {
            if (i & 1) {
                __get_user(env->fpr[i/2].l.lower, src);
            } else {
                __get_user(env->fpr[i/2].l.upper, src);
            }
        }
    }
    __get_user(env->fsr,
               &(ucp->tuc_mcontext.mc_fpregs.mcfpu_fsr));
    __get_user(env->gsr,
               &(ucp->tuc_mcontext.mc_fpregs.mcfpu_gsr));
    unlock_user_struct(ucp, ucp_addr, 0);
    return;
 do_sigsegv:
    unlock_user_struct(ucp, ucp_addr, 0);
    force_sig(TARGET_SIGSEGV);
}

void sparc64_get_context(CPUSPARCState *env)
{
    abi_ulong ucp_addr;
    struct target_ucontext *ucp;
    target_mc_gregset_t *grp;
    target_mcontext_t *mcp;
    abi_ulong fp, i7, w_addr;
    int err;
    unsigned int i;
    target_sigset_t target_set;
    sigset_t set;

    ucp_addr = env->regwptr[UREG_I0];
    if (!lock_user_struct(VERIFY_WRITE, ucp, ucp_addr, 0))
        goto do_sigsegv;
    
    mcp = &ucp->tuc_mcontext;
    grp = &mcp->mc_gregs;

    /* Skip over the trap instruction, first. */
    env->pc = env->npc;
    env->npc += 4;

    err = 0;

    do_sigprocmask(0, NULL, &set);
    host_to_target_sigset_internal(&target_set, &set);
    if (TARGET_NSIG_WORDS == 1) {
        __put_user(target_set.sig[0],
                   (abi_ulong *)&ucp->tuc_sigmask);
    } else {
        abi_ulong *src, *dst;
        src = target_set.sig;
        dst = ucp->tuc_sigmask.sig;
        for (i = 0; i < TARGET_NSIG_WORDS; i++, dst++, src++) {
            __put_user(*src, dst);
        }
        if (err)
            goto do_sigsegv;
    }

    /* XXX: tstate must be saved properly */
    //    __put_user(env->tstate, &((*grp)[MC_TSTATE]));
    __put_user(env->pc, &((*grp)[MC_PC]));
    __put_user(env->npc, &((*grp)[MC_NPC]));
    __put_user(env->y, &((*grp)[MC_Y]));
    __put_user(env->gregs[1], &((*grp)[MC_G1]));
    __put_user(env->gregs[2], &((*grp)[MC_G2]));
    __put_user(env->gregs[3], &((*grp)[MC_G3]));
    __put_user(env->gregs[4], &((*grp)[MC_G4]));
    __put_user(env->gregs[5], &((*grp)[MC_G5]));
    __put_user(env->gregs[6], &((*grp)[MC_G6]));
    __put_user(env->gregs[7], &((*grp)[MC_G7]));
    __put_user(env->regwptr[UREG_I0], &((*grp)[MC_O0]));
    __put_user(env->regwptr[UREG_I1], &((*grp)[MC_O1]));
    __put_user(env->regwptr[UREG_I2], &((*grp)[MC_O2]));
    __put_user(env->regwptr[UREG_I3], &((*grp)[MC_O3]));
    __put_user(env->regwptr[UREG_I4], &((*grp)[MC_O4]));
    __put_user(env->regwptr[UREG_I5], &((*grp)[MC_O5]));
    __put_user(env->regwptr[UREG_I6], &((*grp)[MC_O6]));
    __put_user(env->regwptr[UREG_I7], &((*grp)[MC_O7]));

    w_addr = TARGET_STACK_BIAS+env->regwptr[UREG_I6];
    fp = i7 = 0;
    if (get_user(fp, w_addr + offsetof(struct target_reg_window, ins[6]), 
                 abi_ulong) != 0)
        goto do_sigsegv;
    if (get_user(i7, w_addr + offsetof(struct target_reg_window, ins[7]), 
                 abi_ulong) != 0)
        goto do_sigsegv;
    __put_user(fp, &(mcp->mc_fp));
    __put_user(i7, &(mcp->mc_i7));

    {
        uint32_t *dst = ucp->tuc_mcontext.mc_fpregs.mcfpu_fregs.sregs;
        for (i = 0; i < 64; i++, dst++) {
            if (i & 1) {
                __put_user(env->fpr[i/2].l.lower, dst);
            } else {
                __put_user(env->fpr[i/2].l.upper, dst);
            }
        }
    }
    __put_user(env->fsr, &(mcp->mc_fpregs.mcfpu_fsr));
    __put_user(env->gsr, &(mcp->mc_fpregs.mcfpu_gsr));
    __put_user(env->fprs, &(mcp->mc_fpregs.mcfpu_fprs));

    if (err)
        goto do_sigsegv;
    unlock_user_struct(ucp, ucp_addr, 1);
    return;
 do_sigsegv:
    unlock_user_struct(ucp, ucp_addr, 1);
    force_sig(TARGET_SIGSEGV);
}
#endif
#elif defined(TARGET_MIPS) || defined(TARGET_MIPS64)

# if defined(TARGET_ABI_MIPSO32)
struct target_sigcontext {
    uint32_t   sc_regmask;     /* Unused */
    uint32_t   sc_status;
    uint64_t   sc_pc;
    uint64_t   sc_regs[32];
    uint64_t   sc_fpregs[32];
    uint32_t   sc_ownedfp;     /* Unused */
    uint32_t   sc_fpc_csr;
    uint32_t   sc_fpc_eir;     /* Unused */
    uint32_t   sc_used_math;
    uint32_t   sc_dsp;         /* dsp status, was sc_ssflags */
    uint32_t   pad0;
    uint64_t   sc_mdhi;
    uint64_t   sc_mdlo;
    target_ulong   sc_hi1;         /* Was sc_cause */
    target_ulong   sc_lo1;         /* Was sc_badvaddr */
    target_ulong   sc_hi2;         /* Was sc_sigset[4] */
    target_ulong   sc_lo2;
    target_ulong   sc_hi3;
    target_ulong   sc_lo3;
};
# else /* N32 || N64 */
struct target_sigcontext {
    uint64_t sc_regs[32];
    uint64_t sc_fpregs[32];
    uint64_t sc_mdhi;
    uint64_t sc_hi1;
    uint64_t sc_hi2;
    uint64_t sc_hi3;
    uint64_t sc_mdlo;
    uint64_t sc_lo1;
    uint64_t sc_lo2;
    uint64_t sc_lo3;
    uint64_t sc_pc;
    uint32_t sc_fpc_csr;
    uint32_t sc_used_math;
    uint32_t sc_dsp;
    uint32_t sc_reserved;
};
# endif /* O32 */

struct sigframe {
    uint32_t sf_ass[4];                 /* argument save space for o32 */
    uint32_t sf_code[2];                        /* signal trampoline */
    struct target_sigcontext sf_sc;
    target_sigset_t sf_mask;
};

struct target_ucontext {
    target_ulong tuc_flags;
    target_ulong tuc_link;
    target_stack_t tuc_stack;
    target_ulong pad0;
    struct target_sigcontext tuc_mcontext;
    target_sigset_t tuc_sigmask;
};

struct target_rt_sigframe {
    uint32_t rs_ass[4];               /* argument save space for o32 */
    uint32_t rs_code[2];              /* signal trampoline */
    struct target_siginfo rs_info;
    struct target_ucontext rs_uc;
};

/* Install trampoline to jump back from signal handler */
static inline int install_sigtramp(unsigned int *tramp,   unsigned int syscall)
{
    int err = 0;

    /*
     * Set up the return code ...
     *
     *         li      v0, __NR__foo_sigreturn
     *         syscall
     */

    __put_user(0x24020000 + syscall, tramp + 0);
    __put_user(0x0000000c          , tramp + 1);
    return err;
}

static inline void setup_sigcontext(CPUMIPSState *regs,
        struct target_sigcontext *sc)
{
    int i;

    __put_user(exception_resume_pc(regs), &sc->sc_pc);
    regs->hflags &= ~MIPS_HFLAG_BMASK;

    __put_user(0, &sc->sc_regs[0]);
    for (i = 1; i < 32; ++i) {
        __put_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
    }

    __put_user(regs->active_tc.HI[0], &sc->sc_mdhi);
    __put_user(regs->active_tc.LO[0], &sc->sc_mdlo);

    /* Rather than checking for dsp existence, always copy.  The storage
       would just be garbage otherwise.  */
    __put_user(regs->active_tc.HI[1], &sc->sc_hi1);
    __put_user(regs->active_tc.HI[2], &sc->sc_hi2);
    __put_user(regs->active_tc.HI[3], &sc->sc_hi3);
    __put_user(regs->active_tc.LO[1], &sc->sc_lo1);
    __put_user(regs->active_tc.LO[2], &sc->sc_lo2);
    __put_user(regs->active_tc.LO[3], &sc->sc_lo3);
    {
        uint32_t dsp = cpu_rddsp(0x3ff, regs);
        __put_user(dsp, &sc->sc_dsp);
    }

    __put_user(1, &sc->sc_used_math);

    for (i = 0; i < 32; ++i) {
        __put_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
    }
}

static inline void
restore_sigcontext(CPUMIPSState *regs, struct target_sigcontext *sc)
{
    int i;

    __get_user(regs->CP0_EPC, &sc->sc_pc);

    __get_user(regs->active_tc.HI[0], &sc->sc_mdhi);
    __get_user(regs->active_tc.LO[0], &sc->sc_mdlo);

    for (i = 1; i < 32; ++i) {
        __get_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
    }

    __get_user(regs->active_tc.HI[1], &sc->sc_hi1);
    __get_user(regs->active_tc.HI[2], &sc->sc_hi2);
    __get_user(regs->active_tc.HI[3], &sc->sc_hi3);
    __get_user(regs->active_tc.LO[1], &sc->sc_lo1);
    __get_user(regs->active_tc.LO[2], &sc->sc_lo2);
    __get_user(regs->active_tc.LO[3], &sc->sc_lo3);
    {
        uint32_t dsp;
        __get_user(dsp, &sc->sc_dsp);
        cpu_wrdsp(dsp, 0x3ff, regs);
    }

    for (i = 0; i < 32; ++i) {
        __get_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
    }
}

/*
 * Determine which stack to use..
 */
static inline abi_ulong
get_sigframe(struct target_sigaction *ka, CPUMIPSState *regs, size_t frame_size)
{
    unsigned long sp;

    /* Default to using normal stack */
    sp = regs->active_tc.gpr[29];

    /*
     * FPU emulator may have its own trampoline active just
     * above the user stack, 16-bytes before the next lowest
     * 16 byte boundary.  Try to avoid trashing it.
     */
    sp -= 32;

    /* This is the X/Open sanctioned signal stack switching.  */
    if ((ka->sa_flags & TARGET_SA_ONSTACK) && (sas_ss_flags (sp) == 0)) {
        sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
    }

    return (sp - frame_size) & ~7;
}

static void mips_set_hflags_isa_mode_from_pc(CPUMIPSState *env)
{
    if (env->insn_flags & (ASE_MIPS16 | ASE_MICROMIPS)) {
        env->hflags &= ~MIPS_HFLAG_M16;
        env->hflags |= (env->active_tc.PC & 1) << MIPS_HFLAG_M16_SHIFT;
        env->active_tc.PC &= ~(target_ulong) 1;
    }
}

# if defined(TARGET_ABI_MIPSO32)
/* compare linux/arch/mips/kernel/signal.c:setup_frame() */
static void setup_frame(int sig, struct target_sigaction * ka,
                        target_sigset_t *set, CPUMIPSState *regs)
{
    struct sigframe *frame;
    abi_ulong frame_addr;
    int i;

    frame_addr = get_sigframe(ka, regs, sizeof(*frame));
    trace_user_setup_frame(regs, frame_addr);
    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
        goto give_sigsegv;

    install_sigtramp(frame->sf_code, TARGET_NR_sigreturn);

    setup_sigcontext(regs, &frame->sf_sc);

    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
        __put_user(set->sig[i], &frame->sf_mask.sig[i]);
    }

    /*
    * Arguments to signal handler:
    *
    *   a0 = signal number
    *   a1 = 0 (should be cause)
    *   a2 = pointer to struct sigcontext
    *
    * $25 and PC point to the signal handler, $29 points to the
    * struct sigframe.
    */
    regs->active_tc.gpr[ 4] = sig;
    regs->active_tc.gpr[ 5] = 0;
    regs->active_tc.gpr[ 6] = frame_addr + offsetof(struct sigframe, sf_sc);
    regs->active_tc.gpr[29] = frame_addr;
    regs->active_tc.gpr[31] = frame_addr + offsetof(struct sigframe, sf_code);
    /* The original kernel code sets CP0_EPC to the handler
    * since it returns to userland using eret
    * we cannot do this here, and we must set PC directly */
    regs->active_tc.PC = regs->active_tc.gpr[25] = ka->_sa_handler;
    mips_set_hflags_isa_mode_from_pc(regs);
    unlock_user_struct(frame, frame_addr, 1);
    return;

give_sigsegv:
    force_sig(TARGET_SIGSEGV/*, current*/);
}

long do_sigreturn(CPUMIPSState *regs)
{
    struct sigframe *frame;
    abi_ulong frame_addr;
    sigset_t blocked;
    target_sigset_t target_set;
    int i;

    frame_addr = regs->active_tc.gpr[29];
    trace_user_do_sigreturn(regs, frame_addr);
    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
        goto badframe;

    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
        __get_user(target_set.sig[i], &frame->sf_mask.sig[i]);
    }

    target_to_host_sigset_internal(&blocked, &target_set);
    do_sigprocmask(SIG_SETMASK, &blocked, NULL);

    restore_sigcontext(regs, &frame->sf_sc);

#if 0
    /*
     * Don't let your children do this ...
     */
    __asm__ __volatile__(
        "move\t$29, %0\n\t"
        "j\tsyscall_exit"
        :/* no outputs */
        :"r" (&regs));
    /* Unreached */
#endif

    regs->active_tc.PC = regs->CP0_EPC;
    mips_set_hflags_isa_mode_from_pc(regs);
    /* I am not sure this is right, but it seems to work
    * maybe a problem with nested signals ? */
    regs->CP0_EPC = 0;
    return -TARGET_QEMU_ESIGRETURN;

badframe:
    force_sig(TARGET_SIGSEGV/*, current*/);
    return 0;
}
# endif /* O32 */

static void setup_rt_frame(int sig, struct target_sigaction *ka,
                           target_siginfo_t *info,
                           target_sigset_t *set, CPUMIPSState *env)
{
    struct target_rt_sigframe *frame;
    abi_ulong frame_addr;
    int i;

    frame_addr = get_sigframe(ka, env, sizeof(*frame));
    trace_user_setup_rt_frame(env, frame_addr);
    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
        goto give_sigsegv;

    install_sigtramp(frame->rs_code, TARGET_NR_rt_sigreturn);