Bootlin

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
/*
 *  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/futex.h>	/* for FUTEX_WAIT */
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/security.h>

#include <asm/uaccess.h>

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)
{
	unsigned long expire = restart->arg0, now = jiffies;
	struct compat_timespec __user *rmtp;

	/* Did it expire while we handled signals? */
	if (!time_after(expire, now))
		return 0;

	expire = schedule_timeout_interruptible(expire - now);
	if (expire == 0)
		return 0;

	rmtp = (struct compat_timespec __user *)restart->arg1;
	if (rmtp) {
		struct compat_timespec ct;
		struct timespec t;

		jiffies_to_timespec(expire, &t);
		ct.tv_sec = t.tv_sec;
		ct.tv_nsec = t.tv_nsec;
		if (copy_to_user(rmtp, &ct, sizeof(ct)))
			return -EFAULT;
	}
	/* The 'restart' block is already filled in */
	return -ERESTART_RESTARTBLOCK;
}

asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
		struct compat_timespec __user *rmtp)
{
	struct timespec t;
	struct restart_block *restart;
	unsigned long expire;

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

	if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0))
		return -EINVAL;

	expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
	expire = schedule_timeout_interruptible(expire);
	if (expire == 0)
		return 0;

	if (rmtp) {
		jiffies_to_timespec(expire, &t);
		if (put_compat_timespec(&t, rmtp))
			return -EFAULT;
	}
	restart = &current_thread_info()->restart_block;
	restart->fn = compat_nanosleep_restart;
	restart->arg0 = jiffies + expire;
	restart->arg1 = (unsigned long) rmtp;
	return -ERESTART_RESTARTBLOCK;
}

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;
}

asmlinkage long compat_sys_times(struct compat_tms __user *tbuf)
{
	/*
	 *	In the SMP world we might just be unlucky and have one of
	 *	the times increment as we use it. Since the value is an
	 *	atomically safe type this is just fine. Conceptually its
	 *	as if the syscall took an instant longer to occur.
	 */
	if (tbuf) {
		struct compat_tms tmp;
		struct task_struct *tsk = current;
		struct task_struct *t;
		cputime_t utime, stime, cutime, cstime;

		read_lock(&tasklist_lock);
		utime = tsk->signal->utime;
		stime = tsk->signal->stime;
		t = tsk;
		do {
			utime = cputime_add(utime, t->utime);
			stime = cputime_add(stime, t->stime);
			t = next_thread(t);
		} while (t != tsk);

		/*
		 * While we have tasklist_lock read-locked, no dying thread
		 * can be updating current->signal->[us]time.  Instead,
		 * we got their counts included in the live thread loop.
		 * However, another thread can come in right now and
		 * do a wait call that updates current->signal->c[us]time.
		 * To make sure we always see that pair updated atomically,
		 * we take the siglock around fetching them.
		 */
		spin_lock_irq(&tsk->sighand->siglock);
		cutime = tsk->signal->cutime;
		cstime = tsk->signal->cstime;
		spin_unlock_irq(&tsk->sighand->siglock);
		read_unlock(&tasklist_lock);

		tmp.tms_utime = compat_jiffies_to_clock_t(cputime_to_jiffies(utime));
		tmp.tms_stime = compat_jiffies_to_clock_t(cputime_to_jiffies(stime));
		tmp.tms_cutime = compat_jiffies_to_clock_t(cputime_to_jiffies(cutime));
		tmp.tms_cstime = compat_jiffies_to_clock_t(cputime_to_jiffies(cstime));
		if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
			return -EFAULT;
	}
	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;
}

#ifdef CONFIG_FUTEX
asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, int val,
		struct compat_timespec __user *utime, u32 __user *uaddr2,
		int val3)
{
	struct timespec t;
	unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
	int val2 = 0;

	if ((op == FUTEX_WAIT) && utime) {
		if (get_compat_timespec(&t, utime))
			return -EFAULT;
		timeout = timespec_to_jiffies(&t) + 1;
	}
	if (op >= FUTEX_REQUEUE)
		val2 = (int) (unsigned long) utime;

	return do_futex((unsigned long)uaddr, op, val, timeout,
			(unsigned long)uaddr2, val2, val3);
}
#endif

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

	if (resource >= RLIM_NLIMITS) 
		return -EINVAL;	

	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;
	set_fs(KERNEL_DS);
	ret = sys_setrlimit(resource, (struct rlimit __user *) &r);
	set_fs(old_fs);
	return ret;
}

#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;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	ret = sys_getrlimit(resource, (struct rlimit __user *) &r);
	set_fs(old_fs);
	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, cpumask_t *new_mask)
{
	unsigned long *k;

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

	k = cpus_addr(*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_t new_mask;
	int retval;

	retval = compat_get_user_cpu_mask(user_mask_ptr, len, &new_mask);
	if (retval)
		return retval;

	return sched_setaffinity(pid, new_mask);
}

asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid, unsigned int len,
					     compat_ulong_t __user *user_mask_ptr)
{
	int ret;
	cpumask_t mask;
	unsigned long *k;
	unsigned int min_length = sizeof(cpumask_t);

	if (NR_CPUS <= BITS_PER_COMPAT_LONG)
		min_length = sizeof(compat_ulong_t);

	if (len < min_length)
		return -EINVAL;

	ret = sched_getaffinity(pid, &mask);
	if (ret < 0)
		return ret;

	k = cpus_addr(mask);
	ret = compat_put_bitmap(user_mask_ptr, k, min_length * 8);
	if (ret)
		return ret;

	return min_length;
}

static int get_compat_itimerspec(struct itimerspec *dst, 
				 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;
} 

static int put_compat_itimerspec(struct compat_itimerspec __user *dst, 
				 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_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;
} 

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; 

	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;
	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, 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) {
#if defined (__COMPAT_ENDIAN_SWAP__)
	case 4: set->sig[3] = compat->sig[7] | (((long)compat->sig[6]) << 32 );
	case 3: set->sig[2] = compat->sig[5] | (((long)compat->sig[4]) << 32 );
	case 2: set->sig[1] = compat->sig[3] | (((long)compat->sig[2]) << 32 );
	case 1: set->sig[0] = compat->sig[1] | (((long)compat->sig[0]) << 32 );
#else
	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 );
#endif
	}
}

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;

}

#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))
			i = -EFAULT;
	}
	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_thread_flag(TIF_RESTORE_SIGMASK);
	return -ERESTARTNOHAND;
}
#endif /* __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND */