kernel/compat.c

/*
 *  linux/kernel/compat.c
 *
 *  Kernel compatibililty routines for e.g. 32 bit syscall support
 *  on 64 bit kernels.
 *
 *  Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

#include <linux/linkage.h>
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/signal.h>
#include <linux/sched.h>	/* for MAX_SCHEDULE_TIMEOUT */
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/security.h>
#include <linux/timex.h>
#include <linux/migrate.h>
#include <linux/posix-timers.h>
#include <linux/times.h>
#include <linux/ptrace.h>
#include <linux/gfp.h>

#include <asm/uaccess.h>

/*
 * Note that the native side is already converted to a timespec, because
 * that's what we want anyway.
 */
static int compat_get_timeval(struct timespec *o,
		struct compat_timeval __user *i)
{
	long usec;

	if (get_user(o->tv_sec, &i->tv_sec) ||
	    get_user(usec, &i->tv_usec))
		return -EFAULT;
	o->tv_nsec = usec * 1000;
	return 0;
}

static int compat_put_timeval(struct compat_timeval __user *o,
		struct timeval *i)
{
	return (put_user(i->tv_sec, &o->tv_sec) ||
		put_user(i->tv_usec, &o->tv_usec)) ? -EFAULT : 0;
}

static int compat_get_timex(struct timex *txc, struct compat_timex __user *utp)
{
	memset(txc, 0, sizeof(struct timex));

	if (!access_ok(VERIFY_READ, utp, sizeof(struct compat_timex)) ||
			__get_user(txc->modes, &utp->modes) ||
			__get_user(txc->offset, &utp->offset) ||
			__get_user(txc->freq, &utp->freq) ||
			__get_user(txc->maxerror, &utp->maxerror) ||
			__get_user(txc->esterror, &utp->esterror) ||
			__get_user(txc->status, &utp->status) ||
			__get_user(txc->constant, &utp->constant) ||
			__get_user(txc->precision, &utp->precision) ||
			__get_user(txc->tolerance, &utp->tolerance) ||
			__get_user(txc->time.tv_sec, &utp->time.tv_sec) ||
			__get_user(txc->time.tv_usec, &utp->time.tv_usec) ||
			__get_user(txc->tick, &utp->tick) ||
			__get_user(txc->ppsfreq, &utp->ppsfreq) ||
			__get_user(txc->jitter, &utp->jitter) ||
			__get_user(txc->shift, &utp->shift) ||
			__get_user(txc->stabil, &utp->stabil) ||
			__get_user(txc->jitcnt, &utp->jitcnt) ||
			__get_user(txc->calcnt, &utp->calcnt) ||
			__get_user(txc->errcnt, &utp->errcnt) ||
			__get_user(txc->stbcnt, &utp->stbcnt))
		return -EFAULT;

	return 0;
}

static int compat_put_timex(struct compat_timex __user *utp, struct timex *txc)
{
	if (!access_ok(VERIFY_WRITE, utp, sizeof(struct compat_timex)) ||
			__put_user(txc->modes, &utp->modes) ||
			__put_user(txc->offset, &utp->offset) ||
			__put_user(txc->freq, &utp->freq) ||
			__put_user(txc->maxerror, &utp->maxerror) ||
			__put_user(txc->esterror, &utp->esterror) ||
			__put_user(txc->status, &utp->status) ||
			__put_user(txc->constant, &utp->constant) ||
			__put_user(txc->precision, &utp->precision) ||
			__put_user(txc->tolerance, &utp->tolerance) ||
			__put_user(txc->time.tv_sec, &utp->time.tv_sec) ||
			__put_user(txc->time.tv_usec, &utp->time.tv_usec) ||
			__put_user(txc->tick, &utp->tick) ||
			__put_user(txc->ppsfreq, &utp->ppsfreq) ||
			__put_user(txc->jitter, &utp->jitter) ||
			__put_user(txc->shift, &utp->shift) ||
			__put_user(txc->stabil, &utp->stabil) ||
			__put_user(txc->jitcnt, &utp->jitcnt) ||
			__put_user(txc->calcnt, &utp->calcnt) ||
			__put_user(txc->errcnt, &utp->errcnt) ||
			__put_user(txc->stbcnt, &utp->stbcnt) ||
			__put_user(txc->tai, &utp->tai))
		return -EFAULT;
	return 0;
}

asmlinkage long compat_sys_gettimeofday(struct compat_timeval __user *tv,
		struct timezone __user *tz)
{
	if (tv) {
		struct timeval ktv;
		do_gettimeofday(&ktv);
		if (compat_put_timeval(tv, &ktv))
			return -EFAULT;
	}
	if (tz) {
		if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
			return -EFAULT;
	}

	return 0;
}

asmlinkage long compat_sys_settimeofday(struct compat_timeval __user *tv,
		struct timezone __user *tz)
{
	struct timespec kts;
	struct timezone ktz;

	if (tv) {
		if (compat_get_timeval(&kts, tv))
			return -EFAULT;
	}
	if (tz) {
		if (copy_from_user(&ktz, tz, sizeof(ktz)))
			return -EFAULT;
	}

	return do_sys_settimeofday(tv ? &kts : NULL, tz ? &ktz : NULL);
}

int get_compat_timespec(struct timespec *ts, const struct compat_timespec __user *cts)
{
	return (!access_ok(VERIFY_READ, cts, sizeof(*cts)) ||
			__get_user(ts->tv_sec, &cts->tv_sec) ||
			__get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
}

int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user *cts)
{
	return (!access_ok(VERIFY_WRITE, cts, sizeof(*cts)) ||
			__put_user(ts->tv_sec, &cts->tv_sec) ||
			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
}

static long compat_nanosleep_restart(struct restart_block *restart)
{
	struct compat_timespec __user *rmtp;
	struct timespec rmt;
	mm_segment_t oldfs;
	long ret;

	restart->nanosleep.rmtp = (struct timespec __user *) &rmt;
	oldfs = get_fs();
	set_fs(KERNEL_DS);
	ret = hrtimer_nanosleep_restart(restart);
	set_fs(oldfs);

	if (ret) {
		rmtp = restart->nanosleep.compat_rmtp;

		if (rmtp && put_compat_timespec(&rmt, rmtp))
			return -EFAULT;
	}

	return ret;
}

asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
				     struct compat_timespec __user *rmtp)
{
	struct timespec tu, rmt;
	mm_segment_t oldfs;
	long ret;

	if (get_compat_timespec(&tu, rqtp))
		return -EFAULT;

	if (!timespec_valid(&tu))
		return -EINVAL;

	oldfs = get_fs();
	set_fs(KERNEL_DS);
	ret = hrtimer_nanosleep(&tu,
				rmtp ? (struct timespec __user *)&rmt : NULL,
				HRTIMER_MODE_REL, CLOCK_MONOTONIC);
	set_fs(oldfs);

	if (ret) {
		struct restart_block *restart
			= &current_thread_info()->restart_block;

		restart->fn = compat_nanosleep_restart;
		restart->nanosleep.compat_rmtp = rmtp;

		if (rmtp && put_compat_timespec(&rmt, rmtp))
			return -EFAULT;
	}

	return ret;
}

static inline long get_compat_itimerval(struct itimerval *o,
		struct compat_itimerval __user *i)
{
	return (!access_ok(VERIFY_READ, i, sizeof(*i)) ||
		(__get_user(o->it_interval.tv_sec, &i->it_interval.tv_sec) |
		 __get_user(o->it_interval.tv_usec, &i->it_interval.tv_usec) |
		 __get_user(o->it_value.tv_sec, &i->it_value.tv_sec) |
		 __get_user(o->it_value.tv_usec, &i->it_value.tv_usec)));
}

static inline long put_compat_itimerval(struct compat_itimerval __user *o,
		struct itimerval *i)
{
	return (!access_ok(VERIFY_WRITE, o, sizeof(*o)) ||
		(__put_user(i->it_interval.tv_sec, &o->it_interval.tv_sec) |
		 __put_user(i->it_interval.tv_usec, &o->it_interval.tv_usec) |
		 __put_user(i->it_value.tv_sec, &o->it_value.tv_sec) |
		 __put_user(i->it_value.tv_usec, &o->it_value.tv_usec)));
}

asmlinkage long compat_sys_getitimer(int which,
		struct compat_itimerval __user *it)
{
	struct itimerval kit;
	int error;

	error = do_getitimer(which, &kit);
	if (!error && put_compat_itimerval(it, &kit))
		error = -EFAULT;
	return error;
}

asmlinkage long compat_sys_setitimer(int which,
		struct compat_itimerval __user *in,
		struct compat_itimerval __user *out)
{
	struct itimerval kin, kout;
	int error;

	if (in) {
		if (get_compat_itimerval(&kin, in))
			return -EFAULT;
	} else
		memset(&kin, 0, sizeof(kin));

	error = do_setitimer(which, &kin, out ? &kout : NULL);
	if (error || !out)
		return error;
	if (put_compat_itimerval(out, &kout))
		return -EFAULT;
	return 0;
}

static compat_clock_t clock_t_to_compat_clock_t(clock_t x)
{
	return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));
}

asmlinkage long compat_sys_times(struct compat_tms __user *tbuf)
{
	if (tbuf) {
		struct tms tms;
		struct compat_tms tmp;

		do_sys_times(&tms);
		/* Convert our struct tms to the compat version. */
		tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime);
		tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime);
		tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime);
		tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime);
		if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
			return -EFAULT;
	}
	force_successful_syscall_return();
	return compat_jiffies_to_clock_t(jiffies);
}

/*
 * Assumption: old_sigset_t and compat_old_sigset_t are both
 * types that can be passed to put_user()/get_user().
 */

asmlinkage long compat_sys_sigpending(compat_old_sigset_t __user *set)
{
	old_sigset_t s;
	long ret;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	ret = sys_sigpending((old_sigset_t __user *) &s);
	set_fs(old_fs);
	if (ret == 0)
		ret = put_user(s, set);
	return ret;
}

asmlinkage long compat_sys_sigprocmask(int how, compat_old_sigset_t __user *set,
		compat_old_sigset_t __user *oset)
{
	old_sigset_t s;
	long ret;
	mm_segment_t old_fs;

	if (set && get_user(s, set))
		return -EFAULT;
	old_fs = get_fs();
	set_fs(KERNEL_DS);
	ret = sys_sigprocmask(how,
			      set ? (old_sigset_t __user *) &s : NULL,
			      oset ? (old_sigset_t __user *) &s : NULL);
	set_fs(old_fs);
	if (ret == 0)
		if (oset)
			ret = put_user(s, oset);
	return ret;
}

asmlinkage long compat_sys_setrlimit(unsigned int resource,
		struct compat_rlimit __user *rlim)
{
	struct rlimit r;

	if (!access_ok(VERIFY_READ, rlim, sizeof(*rlim)) ||
	    __get_user(r.rlim_cur, &rlim->rlim_cur) ||
	    __get_user(r.rlim_max, &rlim->rlim_max))
		return -EFAULT;

	if (r.rlim_cur == COMPAT_RLIM_INFINITY)
		r.rlim_cur = RLIM_INFINITY;
	if (r.rlim_max == COMPAT_RLIM_INFINITY)
		r.rlim_max = RLIM_INFINITY;
	return do_prlimit(current, resource, &r, NULL);
}

#ifdef COMPAT_RLIM_OLD_INFINITY

asmlinkage long compat_sys_old_getrlimit(unsigned int resource,
		struct compat_rlimit __user *rlim)
{
	struct rlimit r;
	int ret;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	ret = sys_old_getrlimit(resource, &r);
	set_fs(old_fs);

	if (!ret) {
		if (r.rlim_cur > COMPAT_RLIM_OLD_INFINITY)
			r.rlim_cur = COMPAT_RLIM_INFINITY;
		if (r.rlim_max > COMPAT_RLIM_OLD_INFINITY)
			r.rlim_max = COMPAT_RLIM_INFINITY;

		if (!access_ok(VERIFY_WRITE, rlim, sizeof(*rlim)) ||
		    __put_user(r.rlim_cur, &rlim->rlim_cur) ||
		    __put_user(r.rlim_max, &rlim->rlim_max))
			return -EFAULT;
	}
	return ret;
}

#endif

asmlinkage long compat_sys_getrlimit(unsigned int resource,
		struct compat_rlimit __user *rlim)
{
	struct rlimit r;
	int ret;

	ret = do_prlimit(current, resource, NULL, &r);
	if (!ret) {
		if (r.rlim_cur > COMPAT_RLIM_INFINITY)
			r.rlim_cur = COMPAT_RLIM_INFINITY;
		if (r.rlim_max > COMPAT_RLIM_INFINITY)
			r.rlim_max = COMPAT_RLIM_INFINITY;

		if (!access_ok(VERIFY_WRITE, rlim, sizeof(*rlim)) ||
		    __put_user(r.rlim_cur, &rlim->rlim_cur) ||
		    __put_user(r.rlim_max, &rlim->rlim_max))
			return -EFAULT;
	}
	return ret;
}

int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
{
	if (!access_ok(VERIFY_WRITE, ru, sizeof(*ru)) ||
	    __put_user(r->ru_utime.tv_sec, &ru->ru_utime.tv_sec) ||
	    __put_user(r->ru_utime.tv_usec, &ru->ru_utime.tv_usec) ||
	    __put_user(r->ru_stime.tv_sec, &ru->ru_stime.tv_sec) ||
	    __put_user(r->ru_stime.tv_usec, &ru->ru_stime.tv_usec) ||
	    __put_user(r->ru_maxrss, &ru->ru_maxrss) ||
	    __put_user(r->ru_ixrss, &ru->ru_ixrss) ||
	    __put_user(r->ru_idrss, &ru->ru_idrss) ||
	    __put_user(r->ru_isrss, &ru->ru_isrss) ||
	    __put_user(r->ru_minflt, &ru->ru_minflt) ||
	    __put_user(r->ru_majflt, &ru->ru_majflt) ||
	    __put_user(r->ru_nswap, &ru->ru_nswap) ||
	    __put_user(r->ru_inblock, &ru->ru_inblock) ||
	    __put_user(r->ru_oublock, &ru->ru_oublock) ||
	    __put_user(r->ru_msgsnd, &ru->ru_msgsnd) ||
	    __put_user(r->ru_msgrcv, &ru->ru_msgrcv) ||
	    __put_user(r->ru_nsignals, &ru->ru_nsignals) ||
	    __put_user(r->ru_nvcsw, &ru->ru_nvcsw) ||
	    __put_user(r->ru_nivcsw, &ru->ru_nivcsw))
		return -EFAULT;
	return 0;
}

asmlinkage long compat_sys_getrusage(int who, struct compat_rusage __user *ru)
{
	struct rusage r;
	int ret;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	ret = sys_getrusage(who, (struct rusage __user *) &r);
	set_fs(old_fs);

	if (ret)
		return ret;

	if (put_compat_rusage(&r, ru))
		return -EFAULT;

	return 0;
}

asmlinkage long
compat_sys_wait4(compat_pid_t pid, compat_uint_t __user *stat_addr, int options,
	struct compat_rusage __user *ru)
{
	if (!ru) {
		return sys_wait4(pid, stat_addr, options, NULL);
	} else {
		struct rusage r;
		int ret;
		unsigned int status;
		mm_segment_t old_fs = get_fs();

		set_fs (KERNEL_DS);
		ret = sys_wait4(pid,
				(stat_addr ?
				 (unsigned int __user *) &status : NULL),
				options, (struct rusage __user *) &r);
		set_fs (old_fs);

		if (ret > 0) {
			if (put_compat_rusage(&r, ru))
				return -EFAULT;
			if (stat_addr && put_user(status, stat_addr))
				return -EFAULT;
		}
		return ret;
	}
}

asmlinkage long compat_sys_waitid(int which, compat_pid_t pid,
		struct compat_siginfo __user *uinfo, int options,
		struct compat_rusage __user *uru)
{
	siginfo_t info;
	struct rusage ru;
	long ret;
	mm_segment_t old_fs = get_fs();

	memset(&info, 0, sizeof(info));

	set_fs(KERNEL_DS);
	ret = sys_waitid(which, pid, (siginfo_t __user *)&info, options,
			 uru ? (struct rusage __user *)&ru : NULL);
	set_fs(old_fs);

	if ((ret < 0) || (info.si_signo == 0))
		return ret;

	if (uru) {
		ret = put_compat_rusage(&ru, uru);
		if (ret)
			return ret;
	}

	BUG_ON(info.si_code & __SI_MASK);
	info.si_code |= __SI_CHLD;
	return copy_siginfo_to_user32(uinfo, &info);
}

static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
				    unsigned len, struct cpumask *new_mask)
{
	unsigned long *k;

	if (len < cpumask_size())
		memset(new_mask, 0, cpumask_size());
	else if (len > cpumask_size())
		len = cpumask_size();

	k = cpumask_bits(new_mask);
	return compat_get_bitmap(k, user_mask_ptr, len * 8);
}

asmlinkage long compat_sys_sched_setaffinity(compat_pid_t pid,
					     unsigned int len,
					     compat_ulong_t __user *user_mask_ptr)
{
	cpumask_var_t new_mask;
	int retval;

	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
		return -ENOMEM;

	retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
	if (retval)
		goto out;

	retval = sched_setaffinity(pid, new_mask);
out:
	free_cpumask_var(new_mask);
	return retval;
}

asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid, unsigned int len,
					     compat_ulong_t __user *user_mask_ptr)
{
	int ret;
	cpumask_var_t mask;

	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
		return -EINVAL;
	if (len & (sizeof(compat_ulong_t)-1))
		return -EINVAL;

	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
		return -ENOMEM;

	ret = sched_getaffinity(pid, mask);
	if (ret == 0) {
		size_t retlen = min_t(size_t, len, cpumask_size());

		if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
			ret = -EFAULT;
		else
			ret = retlen;
	}
	free_cpumask_var(mask);

	return ret;
}

int get_compat_itimerspec(struct itimerspec *dst,
			  const struct compat_itimerspec __user *src)
{
	if (get_compat_timespec(&dst->it_interval, &src->it_interval) ||
	    get_compat_timespec(&dst->it_value, &src->it_value))
		return -EFAULT;
	return 0;
}

int put_compat_itimerspec(struct compat_itimerspec __user *dst,
			  const struct itimerspec *src)
{
	if (put_compat_timespec(&src->it_interval, &dst->it_interval) ||
	    put_compat_timespec(&src->it_value, &dst->it_value))
		return -EFAULT;
	return 0;
}

long compat_sys_timer_create(clockid_t which_clock,
			struct compat_sigevent __user *timer_event_spec,
			timer_t __user *created_timer_id)
{
	struct sigevent __user *event = NULL;

	if (timer_event_spec) {
		struct sigevent kevent;

		event = compat_alloc_user_space(sizeof(*event));
		if (get_compat_sigevent(&kevent, timer_event_spec) ||
		    copy_to_user(event, &kevent, sizeof(*event)))
			return -EFAULT;
	}

	return sys_timer_create(which_clock, event, created_timer_id);
}

long compat_sys_timer_settime(timer_t timer_id, int flags,
			  struct compat_itimerspec __user *new,
			  struct compat_itimerspec __user *old)
{
	long err;
	mm_segment_t oldfs;
	struct itimerspec newts, oldts;

	if (!new)
		return -EINVAL;
	if (get_compat_itimerspec(&newts, new))
		return -EFAULT;
	oldfs = get_fs();
	set_fs(KERNEL_DS);
	err = sys_timer_settime(timer_id, flags,
				(struct itimerspec __user *) &newts,
				(struct itimerspec __user *) &oldts);
	set_fs(oldfs);
	if (!err && old && put_compat_itimerspec(old, &oldts))
		return -EFAULT;
	return err;
}

long compat_sys_timer_gettime(timer_t timer_id,
		struct compat_itimerspec __user *setting)
{
	long err;
	mm_segment_t oldfs;
	struct itimerspec ts;

	oldfs = get_fs();
	set_fs(KERNEL_DS);
	err = sys_timer_gettime(timer_id,
				(struct itimerspec __user *) &ts);
	set_fs(oldfs);
	if (!err && put_compat_itimerspec(setting, &ts))
		return -EFAULT;
	return err;
}

long compat_sys_clock_settime(clockid_t which_clock,
		struct compat_timespec __user *tp)
{
	long err;
	mm_segment_t oldfs;
	struct timespec ts;

	if (get_compat_timespec(&ts, tp))
		return -EFAULT;
	oldfs = get_fs();
	set_fs(KERNEL_DS);
	err = sys_clock_settime(which_clock,
				(struct timespec __user *) &ts);
	set_fs(oldfs);
	return err;
}

long compat_sys_clock_gettime(clockid_t which_clock,
		struct compat_timespec __user *tp)
{
	long err;
	mm_segment_t oldfs;
	struct timespec ts;

	oldfs = get_fs();
	set_fs(KERNEL_DS);
	err = sys_clock_gettime(which_clock,
				(struct timespec __user *) &ts);
	set_fs(oldfs);
	if (!err && put_compat_timespec(&ts, tp))
		return -EFAULT;
	return err;
}

long compat_sys_clock_adjtime(clockid_t which_clock,
		struct compat_timex __user *utp)
{
	struct timex txc;
	mm_segment_t oldfs;
	int err, ret;

	err = compat_get_timex(&txc, utp);
	if (err)
		return err;

	oldfs = get_fs();
	set_fs(KERNEL_DS);
	ret = sys_clock_adjtime(which_clock, (struct timex __user *) &txc);
	set_fs(oldfs);

	err = compat_put_timex(utp, &txc);
	if (err)
		return err;

	return ret;
}

long compat_sys_clock_getres(clockid_t which_clock,
		struct compat_timespec __user *tp)
{
	long err;
	mm_segment_t oldfs;
	struct timespec ts;

	oldfs = get_fs();
	set_fs(KERNEL_DS);
	err = sys_clock_getres(which_clock,
			       (struct timespec __user *) &ts);
	set_fs(oldfs);
	if (!err && tp && put_compat_timespec(&ts, tp))
		return -EFAULT;
	return err;
}

static long compat_clock_nanosleep_restart(struct restart_block *restart)
{
	long err;
	mm_segment_t oldfs;
	struct timespec tu;
	struct compat_timespec *rmtp = restart->nanosleep.compat_rmtp;

	restart->nanosleep.rmtp = (struct timespec __user *) &tu;
	oldfs = get_fs();
	set_fs(KERNEL_DS);
	err = clock_nanosleep_restart(restart);
	set_fs(oldfs);

	if ((err == -ERESTART_RESTARTBLOCK) && rmtp &&
	    put_compat_timespec(&tu, rmtp))
		return -EFAULT;

	if (err == -ERESTART_RESTARTBLOCK) {
		restart->fn = compat_clock_nanosleep_restart;
		restart->nanosleep.compat_rmtp = rmtp;
	}
	return err;
}

long compat_sys_clock_nanosleep(clockid_t which_clock, int flags,
			    struct compat_timespec __user *rqtp,
			    struct compat_timespec __user *rmtp)
{
	long err;
	mm_segment_t oldfs;
	struct timespec in, out;
	struct restart_block *restart;

	if (get_compat_timespec(&in, rqtp))
		return -EFAULT;

	oldfs = get_fs();
	set_fs(KERNEL_DS);
	err = sys_clock_nanosleep(which_clock, flags,
				  (struct timespec __user *) &in,
				  (struct timespec __user *) &out);
	set_fs(oldfs);

	if ((err == -ERESTART_RESTARTBLOCK) && rmtp &&
	    put_compat_timespec(&out, rmtp))
		return -EFAULT;

	if (err == -ERESTART_RESTARTBLOCK) {
		restart = &current_thread_info()->restart_block;
		restart->fn = compat_clock_nanosleep_restart;
		restart->nanosleep.compat_rmtp = rmtp;
	}
	return err;
}

/*
 * We currently only need the following fields from the sigevent
 * structure: sigev_value, sigev_signo, sig_notify and (sometimes
 * sigev_notify_thread_id).  The others are handled in user mode.
 * We also assume that copying sigev_value.sival_int is sufficient
 * to keep all the bits of sigev_value.sival_ptr intact.
 */
int get_compat_sigevent(struct sigevent *event,
		const struct compat_sigevent __user *u_event)
{
	memset(event, 0, sizeof(*event));
	return (!access_ok(VERIFY_READ, u_event, sizeof(*u_event)) ||
		__get_user(event->sigev_value.sival_int,
			&u_event->sigev_value.sival_int) ||
		__get_user(event->sigev_signo, &u_event->sigev_signo) ||
		__get_user(event->sigev_notify, &u_event->sigev_notify) ||
		__get_user(event->sigev_notify_thread_id,
			&u_event->sigev_notify_thread_id))
		? -EFAULT : 0;
}

long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
		       unsigned long bitmap_size)
{
	int i, j;
	unsigned long m;
	compat_ulong_t um;
	unsigned long nr_compat_longs;

	/* align bitmap up to nearest compat_long_t boundary */
	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);

	if (!access_ok(VERIFY_READ, umask, bitmap_size / 8))
		return -EFAULT;

	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);

	for (i = 0; i < BITS_TO_LONGS(bitmap_size); i++) {
		m = 0;

		for (j = 0; j < sizeof(m)/sizeof(um); j++) {
			/*
			 * We dont want to read past the end of the userspace
			 * bitmap. We must however ensure the end of the
			 * kernel bitmap is zeroed.
			 */
			if (nr_compat_longs-- > 0) {
				if (__get_user(um, umask))
					return -EFAULT;
			} else {
				um = 0;
			}

			umask++;
			m |= (long)um << (j * BITS_PER_COMPAT_LONG);
		}
		*mask++ = m;
	}

	return 0;
}

long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
		       unsigned long bitmap_size)
{
	int i, j;
	unsigned long m;
	compat_ulong_t um;
	unsigned long nr_compat_longs;

	/* align bitmap up to nearest compat_long_t boundary */
	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);

	if (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8))
		return -EFAULT;

	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);

	for (i = 0; i < BITS_TO_LONGS(bitmap_size); i++) {
		m = *mask++;

		for (j = 0; j < sizeof(m)/sizeof(um); j++) {
			um = m;

			/*
			 * We dont want to write past the end of the userspace
			 * bitmap.
			 */
			if (nr_compat_longs-- > 0) {
				if (__put_user(um, umask))
					return -EFAULT;
			}

			umask++;
			m >>= 4*sizeof(um);
			m >>= 4*sizeof(um);
		}
	}

	return 0;
}

void
sigset_from_compat (sigset_t *set, compat_sigset_t *compat)
{
	switch (_NSIG_WORDS) {
	case 4: set->sig[3] = compat->sig[6] | (((long)compat->sig[7]) << 32 );
	case 3: set->sig[2] = compat->sig[4] | (((long)compat->sig[5]) << 32 );
	case 2: set->sig[1] = compat->sig[2] | (((long)compat->sig[3]) << 32 );
	case 1: set->sig[0] = compat->sig[0] | (((long)compat->sig[1]) << 32 );
	}
}

asmlinkage long
compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
		struct compat_siginfo __user *uinfo,
		struct compat_timespec __user *uts, compat_size_t sigsetsize)
{
	compat_sigset_t s32;
	sigset_t s;
	int sig;
	struct timespec t;
	siginfo_t info;
	long ret, timeout = 0;

	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	if (copy_from_user(&s32, uthese, sizeof(compat_sigset_t)))
		return -EFAULT;
	sigset_from_compat(&s, &s32);
	sigdelsetmask(&s,sigmask(SIGKILL)|sigmask(SIGSTOP));
	signotset(&s);

	if (uts) {
		if (get_compat_timespec (&t, uts))
			return -EFAULT;
		if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0
				|| t.tv_sec < 0)
			return -EINVAL;
	}

	spin_lock_irq(&current->sighand->siglock);
	sig = dequeue_signal(current, &s, &info);
	if (!sig) {
		timeout = MAX_SCHEDULE_TIMEOUT;
		if (uts)
			timeout = timespec_to_jiffies(&t)
				+(t.tv_sec || t.tv_nsec);
		if (timeout) {
			current->real_blocked = current->blocked;
			sigandsets(&current->blocked, &current->blocked, &s);

			recalc_sigpending();
			spin_unlock_irq(&current->sighand->siglock);

			timeout = schedule_timeout_interruptible(timeout);

			spin_lock_irq(&current->sighand->siglock);
			sig = dequeue_signal(current, &s, &info);
			current->blocked = current->real_blocked;
			siginitset(&current->real_blocked, 0);
			recalc_sigpending();
		}
	}
	spin_unlock_irq(&current->sighand->siglock);

	if (sig) {
		ret = sig;
		if (uinfo) {
			if (copy_siginfo_to_user32(uinfo, &info))
				ret = -EFAULT;
		}
	}else {
		ret = timeout?-EINTR:-EAGAIN;
	}
	return ret;

}

asmlinkage long
compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid, compat_pid_t pid, int sig,
			     struct compat_siginfo __user *uinfo)
{
	siginfo_t info;

	if (copy_siginfo_from_user32(&info, uinfo))
		return -EFAULT;
	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
}

#ifdef __ARCH_WANT_COMPAT_SYS_TIME

/* compat_time_t is a 32 bit "long" and needs to get converted. */

asmlinkage long compat_sys_time(compat_time_t __user * tloc)
{
	compat_time_t i;
	struct timeval tv;

	do_gettimeofday(&tv);
	i = tv.tv_sec;

	if (tloc) {
		if (put_user(i,tloc))
			return -EFAULT;
	}
	force_successful_syscall_return();
	return i;
}

asmlinkage long compat_sys_stime(compat_time_t __user *tptr)
{
	struct timespec tv;
	int err;

	if (get_user(tv.tv_sec, tptr))
		return -EFAULT;

	tv.tv_nsec = 0;

	err = security_settime(&tv, NULL);
	if (err)
		return err;

	do_settimeofday(&tv);
	return 0;
}

#endif /* __ARCH_WANT_COMPAT_SYS_TIME */

#ifdef __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
asmlinkage long compat_sys_rt_sigsuspend(compat_sigset_t __user *unewset, compat_size_t sigsetsize)
{
	sigset_t newset;
	compat_sigset_t newset32;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
		return -EFAULT;
	sigset_from_compat(&newset, &newset32);
	sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));

	spin_lock_irq(&current->sighand->siglock);
	current->saved_sigmask = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	current->state = TASK_INTERRUPTIBLE;
	schedule();
	set_restore_sigmask();
	return -ERESTARTNOHAND;
}
#endif /* __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND */

asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp)
{
	struct timex txc;
	int err, ret;

	err = compat_get_timex(&txc, utp);
	if (err)
		return err;

	ret = do_adjtimex(&txc);

	err = compat_put_timex(utp, &txc);
	if (err)
		return err;

	return ret;
}

#ifdef CONFIG_NUMA
asmlinkage long compat_sys_move_pages(pid_t pid, unsigned long nr_pages,
		compat_uptr_t __user *pages32,
		const int __user *nodes,
		int __user *status,
		int flags)
{
	const void __user * __user *pages;
	int i;

	pages = compat_alloc_user_space(nr_pages * sizeof(void *));
	for (i = 0; i < nr_pages; i++) {
		compat_uptr_t p;

		if (get_user(p, pages32 + i) ||
			put_user(compat_ptr(p), pages + i))
			return -EFAULT;
	}
	return sys_move_pages(pid, nr_pages, pages, nodes, status, flags);
}

asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
			compat_ulong_t maxnode,
			const compat_ulong_t __user *old_nodes,
			const compat_ulong_t __user *new_nodes)
{
	unsigned long __user *old = NULL;
	unsigned long __user *new = NULL;
	nodemask_t tmp_mask;
	unsigned long nr_bits;
	unsigned long size;

	nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
	size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
	if (old_nodes) {
		if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
			return -EFAULT;
		old = compat_alloc_user_space(new_nodes ? size * 2 : size);
		if (new_nodes)
			new = old + size / sizeof(unsigned long);
		if (copy_to_user(old, nodes_addr(tmp_mask), size))
			return -EFAULT;
	}
	if (new_nodes) {
		if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
			return -EFAULT;
		if (new == NULL)
			new = compat_alloc_user_space(size);
		if (copy_to_user(new, nodes_addr(tmp_mask), size))
			return -EFAULT;
	}
	return sys_migrate_pages(pid, nr_bits + 1, old, new);
}
#endif

struct compat_sysinfo {
	s32 uptime;
	u32 loads[3];
	u32 totalram;
	u32 freeram;
	u32 sharedram;
	u32 bufferram;
	u32 totalswap;
	u32 freeswap;
	u16 procs;
	u16 pad;
	u32 totalhigh;
	u32 freehigh;
	u32 mem_unit;
	char _f[20-2*sizeof(u32)-sizeof(int)];
};

asmlinkage long
compat_sys_sysinfo(struct compat_sysinfo __user *info)
{
	struct sysinfo s;

	do_sysinfo(&s);

	/* Check to see if any memory value is too large for 32-bit and scale
	 *  down if needed
	 */
	if ((s.totalram >> 32) || (s.totalswap >> 32)) {
		int bitcount = 0;

		while (s.mem_unit < PAGE_SIZE) {
			s.mem_unit <<= 1;
			bitcount++;
		}

		s.totalram >>= bitcount;
		s.freeram >>= bitcount;
		s.sharedram >>= bitcount;
		s.bufferram >>= bitcount;
		s.totalswap >>= bitcount;
		s.freeswap >>= bitcount;
		s.totalhigh >>= bitcount;
		s.freehigh >>= bitcount;
	}

	if (!access_ok(VERIFY_WRITE, info, sizeof(struct compat_sysinfo)) ||
	    __put_user (s.uptime, &info->uptime) ||
	    __put_user (s.loads[0], &info->loads[0]) ||
	    __put_user (s.loads[1], &info->loads[1]) ||
	    __put_user (s.loads[2], &info->loads[2]) ||
	    __put_user (s.totalram, &info->totalram) ||
	    __put_user (s.freeram, &info->freeram) ||
	    __put_user (s.sharedram, &info->sharedram) ||
	    __put_user (s.bufferram, &info->bufferram) ||
	    __put_user (s.totalswap, &info->totalswap) ||
	    __put_user (s.freeswap, &info->freeswap) ||
	    __put_user (s.procs, &info->procs) ||
	    __put_user (s.totalhigh, &info->totalhigh) ||
	    __put_user (s.freehigh, &info->freehigh) ||
	    __put_user (s.mem_unit, &info->mem_unit))
		return -EFAULT;

	return 0;
}

/*
 * Allocate user-space memory for the duration of a single system call,
 * in order to marshall parameters inside a compat thunk.
 */
void __user *compat_alloc_user_space(unsigned long len)
{
	void __user *ptr;

	/* If len would occupy more than half of the entire compat space... */
	if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
		return NULL;

	ptr = arch_compat_alloc_user_space(len);

	if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
		return NULL;

	return ptr;
}
EXPORT_SYMBOL_GPL(compat_alloc_user_space);