Free Electrons

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
/*
 *  arch/s390x/kernel/linux32.c
 *
 *  S390 version
 *    Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *               Gerhard Tonn (ton@de.ibm.com)   
 *               Thomas Spatzier (tspat@de.ibm.com)
 *
 *  Conversion between 31bit and 64bit native syscalls.
 *
 * Heavily inspired by the 32-bit Sparc compat code which is 
 * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
 *
 */


#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fs.h> 
#include <linux/mm.h> 
#include <linux/file.h> 
#include <linux/signal.h>
#include <linux/resource.h>
#include <linux/times.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/uio.h>
#include <linux/quota.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/personality.h>
#include <linux/stat.h>
#include <linux/filter.h>
#include <linux/highmem.h>
#include <linux/highuid.h>
#include <linux/mman.h>
#include <linux/ipv6.h>
#include <linux/in.h>
#include <linux/icmpv6.h>
#include <linux/syscalls.h>
#include <linux/sysctl.h>
#include <linux/binfmts.h>
#include <linux/capability.h>
#include <linux/compat.h>
#include <linux/vfs.h>
#include <linux/ptrace.h>
#include <linux/fadvise.h>
#include <linux/ipc.h>
#include <linux/slab.h>

#include <asm/types.h>
#include <asm/uaccess.h>

#include <net/scm.h>
#include <net/sock.h>

#include "compat_linux.h"

u32 psw32_user_bits = PSW32_MASK_DAT | PSW32_MASK_IO | PSW32_MASK_EXT |
		      PSW32_DEFAULT_KEY | PSW32_MASK_BASE | PSW32_MASK_MCHECK |
		      PSW32_MASK_PSTATE | PSW32_ASC_HOME;
 
/* For this source file, we want overflow handling. */

#undef high2lowuid
#undef high2lowgid
#undef low2highuid
#undef low2highgid
#undef SET_UID16
#undef SET_GID16
#undef NEW_TO_OLD_UID
#undef NEW_TO_OLD_GID
#undef SET_OLDSTAT_UID
#undef SET_OLDSTAT_GID
#undef SET_STAT_UID
#undef SET_STAT_GID

#define high2lowuid(uid) ((uid) > 65535) ? (u16)overflowuid : (u16)(uid)
#define high2lowgid(gid) ((gid) > 65535) ? (u16)overflowgid : (u16)(gid)
#define low2highuid(uid) ((uid) == (u16)-1) ? (uid_t)-1 : (uid_t)(uid)
#define low2highgid(gid) ((gid) == (u16)-1) ? (gid_t)-1 : (gid_t)(gid)
#define SET_UID16(var, uid)	var = high2lowuid(uid)
#define SET_GID16(var, gid)	var = high2lowgid(gid)
#define NEW_TO_OLD_UID(uid)	high2lowuid(uid)
#define NEW_TO_OLD_GID(gid)	high2lowgid(gid)
#define SET_OLDSTAT_UID(stat, uid)	(stat).st_uid = high2lowuid(uid)
#define SET_OLDSTAT_GID(stat, gid)	(stat).st_gid = high2lowgid(gid)
#define SET_STAT_UID(stat, uid)		(stat).st_uid = high2lowuid(uid)
#define SET_STAT_GID(stat, gid)		(stat).st_gid = high2lowgid(gid)

asmlinkage long sys32_chown16(const char __user * filename, u16 user, u16 group)
{
	return sys_chown(filename, low2highuid(user), low2highgid(group));
}

asmlinkage long sys32_lchown16(const char __user * filename, u16 user, u16 group)
{
	return sys_lchown(filename, low2highuid(user), low2highgid(group));
}

asmlinkage long sys32_fchown16(unsigned int fd, u16 user, u16 group)
{
	return sys_fchown(fd, low2highuid(user), low2highgid(group));
}

asmlinkage long sys32_setregid16(u16 rgid, u16 egid)
{
	return sys_setregid(low2highgid(rgid), low2highgid(egid));
}

asmlinkage long sys32_setgid16(u16 gid)
{
	return sys_setgid((gid_t)gid);
}

asmlinkage long sys32_setreuid16(u16 ruid, u16 euid)
{
	return sys_setreuid(low2highuid(ruid), low2highuid(euid));
}

asmlinkage long sys32_setuid16(u16 uid)
{
	return sys_setuid((uid_t)uid);
}

asmlinkage long sys32_setresuid16(u16 ruid, u16 euid, u16 suid)
{
	return sys_setresuid(low2highuid(ruid), low2highuid(euid),
		low2highuid(suid));
}

asmlinkage long sys32_getresuid16(u16 __user *ruid, u16 __user *euid, u16 __user *suid)
{
	int retval;

	if (!(retval = put_user(high2lowuid(current->cred->uid), ruid)) &&
	    !(retval = put_user(high2lowuid(current->cred->euid), euid)))
		retval = put_user(high2lowuid(current->cred->suid), suid);

	return retval;
}

asmlinkage long sys32_setresgid16(u16 rgid, u16 egid, u16 sgid)
{
	return sys_setresgid(low2highgid(rgid), low2highgid(egid),
		low2highgid(sgid));
}

asmlinkage long sys32_getresgid16(u16 __user *rgid, u16 __user *egid, u16 __user *sgid)
{
	int retval;

	if (!(retval = put_user(high2lowgid(current->cred->gid), rgid)) &&
	    !(retval = put_user(high2lowgid(current->cred->egid), egid)))
		retval = put_user(high2lowgid(current->cred->sgid), sgid);

	return retval;
}

asmlinkage long sys32_setfsuid16(u16 uid)
{
	return sys_setfsuid((uid_t)uid);
}

asmlinkage long sys32_setfsgid16(u16 gid)
{
	return sys_setfsgid((gid_t)gid);
}

static int groups16_to_user(u16 __user *grouplist, struct group_info *group_info)
{
	int i;
	u16 group;

	for (i = 0; i < group_info->ngroups; i++) {
		group = (u16)GROUP_AT(group_info, i);
		if (put_user(group, grouplist+i))
			return -EFAULT;
	}

	return 0;
}

static int groups16_from_user(struct group_info *group_info, u16 __user *grouplist)
{
	int i;
	u16 group;

	for (i = 0; i < group_info->ngroups; i++) {
		if (get_user(group, grouplist+i))
			return  -EFAULT;
		GROUP_AT(group_info, i) = (gid_t)group;
	}

	return 0;
}

asmlinkage long sys32_getgroups16(int gidsetsize, u16 __user *grouplist)
{
	int i;

	if (gidsetsize < 0)
		return -EINVAL;

	get_group_info(current->cred->group_info);
	i = current->cred->group_info->ngroups;
	if (gidsetsize) {
		if (i > gidsetsize) {
			i = -EINVAL;
			goto out;
		}
		if (groups16_to_user(grouplist, current->cred->group_info)) {
			i = -EFAULT;
			goto out;
		}
	}
out:
	put_group_info(current->cred->group_info);
	return i;
}

asmlinkage long sys32_setgroups16(int gidsetsize, u16 __user *grouplist)
{
	struct group_info *group_info;
	int retval;

	if (!capable(CAP_SETGID))
		return -EPERM;
	if ((unsigned)gidsetsize > NGROUPS_MAX)
		return -EINVAL;

	group_info = groups_alloc(gidsetsize);
	if (!group_info)
		return -ENOMEM;
	retval = groups16_from_user(group_info, grouplist);
	if (retval) {
		put_group_info(group_info);
		return retval;
	}

	retval = set_current_groups(group_info);
	put_group_info(group_info);

	return retval;
}

asmlinkage long sys32_getuid16(void)
{
	return high2lowuid(current->cred->uid);
}

asmlinkage long sys32_geteuid16(void)
{
	return high2lowuid(current->cred->euid);
}

asmlinkage long sys32_getgid16(void)
{
	return high2lowgid(current->cred->gid);
}

asmlinkage long sys32_getegid16(void)
{
	return high2lowgid(current->cred->egid);
}

/*
 * sys32_ipc() is the de-multiplexer for the SysV IPC calls in 32bit emulation.
 *
 * This is really horribly ugly.
 */
#ifdef CONFIG_SYSVIPC
asmlinkage long sys32_ipc(u32 call, int first, int second, int third, u32 ptr)
{
	if (call >> 16)		/* hack for backward compatibility */
		return -EINVAL;
	switch (call) {
	case SEMTIMEDOP:
		return compat_sys_semtimedop(first, compat_ptr(ptr),
					     second, compat_ptr(third));
	case SEMOP:
		/* struct sembuf is the same on 32 and 64bit :)) */
		return sys_semtimedop(first, compat_ptr(ptr),
				      second, NULL);
	case SEMGET:
		return sys_semget(first, second, third);
	case SEMCTL:
		return compat_sys_semctl(first, second, third,
					 compat_ptr(ptr));
	case MSGSND:
		return compat_sys_msgsnd(first, second, third,
					 compat_ptr(ptr));
	case MSGRCV:
		return compat_sys_msgrcv(first, second, 0, third,
					 0, compat_ptr(ptr));
	case MSGGET:
		return sys_msgget((key_t) first, second);
	case MSGCTL:
		return compat_sys_msgctl(first, second, compat_ptr(ptr));
	case SHMAT:
		return compat_sys_shmat(first, second, third,
					0, compat_ptr(ptr));
	case SHMDT:
		return sys_shmdt(compat_ptr(ptr));
	case SHMGET:
		return sys_shmget(first, (unsigned)second, third);
	case SHMCTL:
		return compat_sys_shmctl(first, second, compat_ptr(ptr));
	}

	return -ENOSYS;
}
#endif

asmlinkage long sys32_truncate64(const char __user * path, unsigned long high, unsigned long low)
{
	if ((int)high < 0)
		return -EINVAL;
	else
		return sys_truncate(path, (high << 32) | low);
}

asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long high, unsigned long low)
{
	if ((int)high < 0)
		return -EINVAL;
	else
		return sys_ftruncate(fd, (high << 32) | low);
}

asmlinkage long sys32_sched_rr_get_interval(compat_pid_t pid,
				struct compat_timespec __user *interval)
{
	struct timespec t;
	int ret;
	mm_segment_t old_fs = get_fs ();
	
	set_fs (KERNEL_DS);
	ret = sys_sched_rr_get_interval(pid,
					(struct timespec __force __user *) &t);
	set_fs (old_fs);
	if (put_compat_timespec(&t, interval))
		return -EFAULT;
	return ret;
}

asmlinkage long sys32_rt_sigprocmask(int how, compat_sigset_t __user *set,
			compat_sigset_t __user *oset, size_t sigsetsize)
{
	sigset_t s;
	compat_sigset_t s32;
	int ret;
	mm_segment_t old_fs = get_fs();
	
	if (set) {
		if (copy_from_user (&s32, set, sizeof(compat_sigset_t)))
			return -EFAULT;
		s.sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
	}
	set_fs (KERNEL_DS);
	ret = sys_rt_sigprocmask(how,
				 set ? (sigset_t __force __user *) &s : NULL,
				 oset ? (sigset_t __force __user *) &s : NULL,
				 sigsetsize);
	set_fs (old_fs);
	if (ret) return ret;
	if (oset) {
		s32.sig[1] = (s.sig[0] >> 32);
		s32.sig[0] = s.sig[0];
		if (copy_to_user (oset, &s32, sizeof(compat_sigset_t)))
			return -EFAULT;
	}
	return 0;
}

asmlinkage long sys32_rt_sigpending(compat_sigset_t __user *set,
				size_t sigsetsize)
{
	sigset_t s;
	compat_sigset_t s32;
	int ret;
	mm_segment_t old_fs = get_fs();
		
	set_fs (KERNEL_DS);
	ret = sys_rt_sigpending((sigset_t __force __user *) &s, sigsetsize);
	set_fs (old_fs);
	if (!ret) {
		s32.sig[1] = (s.sig[0] >> 32);
		s32.sig[0] = s.sig[0];
		if (copy_to_user (set, &s32, sizeof(compat_sigset_t)))
			return -EFAULT;
	}
	return ret;
}

asmlinkage long
sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo)
{
	siginfo_t info;
	int ret;
	mm_segment_t old_fs = get_fs();
	
	if (copy_siginfo_from_user32(&info, uinfo))
		return -EFAULT;
	set_fs (KERNEL_DS);
	ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __force __user *) &info);
	set_fs (old_fs);
	return ret;
}

/*
 * sys32_execve() executes a new program after the asm stub has set
 * things up for us.  This should basically do what I want it to.
 */
asmlinkage long sys32_execve(const char __user *name, compat_uptr_t __user *argv,
			     compat_uptr_t __user *envp)
{
	struct pt_regs *regs = task_pt_regs(current);
	char *filename;
	long rc;

	filename = getname(name);
	rc = PTR_ERR(filename);
	if (IS_ERR(filename))
		return rc;
	rc = compat_do_execve(filename, argv, envp, regs);
	if (rc)
		goto out;
	current->thread.fp_regs.fpc=0;
	asm volatile("sfpc %0,0" : : "d" (0));
	rc = regs->gprs[2];
out:
	putname(filename);
	return rc;
}

asmlinkage long sys32_pread64(unsigned int fd, char __user *ubuf,
				size_t count, u32 poshi, u32 poslo)
{
	if ((compat_ssize_t) count < 0)
		return -EINVAL;
	return sys_pread64(fd, ubuf, count, ((loff_t)AA(poshi) << 32) | AA(poslo));
}

asmlinkage long sys32_pwrite64(unsigned int fd, const char __user *ubuf,
				size_t count, u32 poshi, u32 poslo)
{
	if ((compat_ssize_t) count < 0)
		return -EINVAL;
	return sys_pwrite64(fd, ubuf, count, ((loff_t)AA(poshi) << 32) | AA(poslo));
}

asmlinkage compat_ssize_t sys32_readahead(int fd, u32 offhi, u32 offlo, s32 count)
{
	return sys_readahead(fd, ((loff_t)AA(offhi) << 32) | AA(offlo), count);
}

asmlinkage long sys32_sendfile(int out_fd, int in_fd, compat_off_t __user *offset, size_t count)
{
	mm_segment_t old_fs = get_fs();
	int ret;
	off_t of;
	
	if (offset && get_user(of, offset))
		return -EFAULT;
		
	set_fs(KERNEL_DS);
	ret = sys_sendfile(out_fd, in_fd,
			   offset ? (off_t __force __user *) &of : NULL, count);
	set_fs(old_fs);
	
	if (offset && put_user(of, offset))
		return -EFAULT;
		
	return ret;
}

asmlinkage long sys32_sendfile64(int out_fd, int in_fd,
				compat_loff_t __user *offset, s32 count)
{
	mm_segment_t old_fs = get_fs();
	int ret;
	loff_t lof;
	
	if (offset && get_user(lof, offset))
		return -EFAULT;
		
	set_fs(KERNEL_DS);
	ret = sys_sendfile64(out_fd, in_fd,
			     offset ? (loff_t __force __user *) &lof : NULL,
			     count);
	set_fs(old_fs);
	
	if (offset && put_user(lof, offset))
		return -EFAULT;
		
	return ret;
}

struct stat64_emu31 {
	unsigned long long  st_dev;
	unsigned int    __pad1;
#define STAT64_HAS_BROKEN_ST_INO        1
	u32             __st_ino;
	unsigned int    st_mode;
	unsigned int    st_nlink;
	u32             st_uid;
	u32             st_gid;
	unsigned long long  st_rdev;
	unsigned int    __pad3;
	long            st_size;
	u32             st_blksize;
	unsigned char   __pad4[4];
	u32             __pad5;     /* future possible st_blocks high bits */
	u32             st_blocks;  /* Number 512-byte blocks allocated. */
	u32             st_atime;
	u32             __pad6;
	u32             st_mtime;
	u32             __pad7;
	u32             st_ctime;
	u32             __pad8;     /* will be high 32 bits of ctime someday */
	unsigned long   st_ino;
};	

static int cp_stat64(struct stat64_emu31 __user *ubuf, struct kstat *stat)
{
	struct stat64_emu31 tmp;

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

	tmp.st_dev = huge_encode_dev(stat->dev);
	tmp.st_ino = stat->ino;
	tmp.__st_ino = (u32)stat->ino;
	tmp.st_mode = stat->mode;
	tmp.st_nlink = (unsigned int)stat->nlink;
	tmp.st_uid = stat->uid;
	tmp.st_gid = stat->gid;
	tmp.st_rdev = huge_encode_dev(stat->rdev);
	tmp.st_size = stat->size;
	tmp.st_blksize = (u32)stat->blksize;
	tmp.st_blocks = (u32)stat->blocks;
	tmp.st_atime = (u32)stat->atime.tv_sec;
	tmp.st_mtime = (u32)stat->mtime.tv_sec;
	tmp.st_ctime = (u32)stat->ctime.tv_sec;

	return copy_to_user(ubuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 
}

asmlinkage long sys32_stat64(const char __user * filename, struct stat64_emu31 __user * statbuf)
{
	struct kstat stat;
	int ret = vfs_stat(filename, &stat);
	if (!ret)
		ret = cp_stat64(statbuf, &stat);
	return ret;
}

asmlinkage long sys32_lstat64(const char __user * filename, struct stat64_emu31 __user * statbuf)
{
	struct kstat stat;
	int ret = vfs_lstat(filename, &stat);
	if (!ret)
		ret = cp_stat64(statbuf, &stat);
	return ret;
}

asmlinkage long sys32_fstat64(unsigned long fd, struct stat64_emu31 __user * statbuf)
{
	struct kstat stat;
	int ret = vfs_fstat(fd, &stat);
	if (!ret)
		ret = cp_stat64(statbuf, &stat);
	return ret;
}

asmlinkage long sys32_fstatat64(unsigned int dfd, const char __user *filename,
				struct stat64_emu31 __user* statbuf, int flag)
{
	struct kstat stat;
	int error;

	error = vfs_fstatat(dfd, filename, &stat, flag);
	if (error)
		return error;
	return cp_stat64(statbuf, &stat);
}

/*
 * Linux/i386 didn't use to be able to handle more than
 * 4 system call parameters, so these system calls used a memory
 * block for parameter passing..
 */

struct mmap_arg_struct_emu31 {
	compat_ulong_t addr;
	compat_ulong_t len;
	compat_ulong_t prot;
	compat_ulong_t flags;
	compat_ulong_t fd;
	compat_ulong_t offset;
};

asmlinkage unsigned long old32_mmap(struct mmap_arg_struct_emu31 __user *arg)
{
	struct mmap_arg_struct_emu31 a;

	if (copy_from_user(&a, arg, sizeof(a)))
		return -EFAULT;
	if (a.offset & ~PAGE_MASK)
		return -EINVAL;
	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
			      a.offset >> PAGE_SHIFT);
}

asmlinkage long sys32_mmap2(struct mmap_arg_struct_emu31 __user *arg)
{
	struct mmap_arg_struct_emu31 a;

	if (copy_from_user(&a, arg, sizeof(a)))
		return -EFAULT;
	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
}

asmlinkage long sys32_read(unsigned int fd, char __user * buf, size_t count)
{
	if ((compat_ssize_t) count < 0)
		return -EINVAL; 

	return sys_read(fd, buf, count);
}

asmlinkage long sys32_write(unsigned int fd, const char __user * buf, size_t count)
{
	if ((compat_ssize_t) count < 0)
		return -EINVAL; 

	return sys_write(fd, buf, count);
}

/*
 * 31 bit emulation wrapper functions for sys_fadvise64/fadvise64_64.
 * These need to rewrite the advise values for POSIX_FADV_{DONTNEED,NOREUSE}
 * because the 31 bit values differ from the 64 bit values.
 */

asmlinkage long
sys32_fadvise64(int fd, loff_t offset, size_t len, int advise)
{
	if (advise == 4)
		advise = POSIX_FADV_DONTNEED;
	else if (advise == 5)
		advise = POSIX_FADV_NOREUSE;
	return sys_fadvise64(fd, offset, len, advise);
}

struct fadvise64_64_args {
	int fd;
	long long offset;
	long long len;
	int advice;
};

asmlinkage long
sys32_fadvise64_64(struct fadvise64_64_args __user *args)
{
	struct fadvise64_64_args a;

	if ( copy_from_user(&a, args, sizeof(a)) )
		return -EFAULT;
	if (a.advice == 4)
		a.advice = POSIX_FADV_DONTNEED;
	else if (a.advice == 5)
		a.advice = POSIX_FADV_NOREUSE;
	return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
}