xref: /openbmc/linux/arch/s390/kernel/compat_linux.c (revision a09d2831)
1 /*
2  *  arch/s390x/kernel/linux32.c
3  *
4  *  S390 version
5  *    Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7  *               Gerhard Tonn (ton@de.ibm.com)
8  *               Thomas Spatzier (tspat@de.ibm.com)
9  *
10  *  Conversion between 31bit and 64bit native syscalls.
11  *
12  * Heavily inspired by the 32-bit Sparc compat code which is
13  * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
14  * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
15  *
16  */
17 
18 
19 #include <linux/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/fs.h>
22 #include <linux/mm.h>
23 #include <linux/file.h>
24 #include <linux/signal.h>
25 #include <linux/resource.h>
26 #include <linux/times.h>
27 #include <linux/smp.h>
28 #include <linux/smp_lock.h>
29 #include <linux/sem.h>
30 #include <linux/msg.h>
31 #include <linux/shm.h>
32 #include <linux/slab.h>
33 #include <linux/uio.h>
34 #include <linux/quota.h>
35 #include <linux/module.h>
36 #include <linux/poll.h>
37 #include <linux/personality.h>
38 #include <linux/stat.h>
39 #include <linux/filter.h>
40 #include <linux/highmem.h>
41 #include <linux/highuid.h>
42 #include <linux/mman.h>
43 #include <linux/ipv6.h>
44 #include <linux/in.h>
45 #include <linux/icmpv6.h>
46 #include <linux/syscalls.h>
47 #include <linux/sysctl.h>
48 #include <linux/binfmts.h>
49 #include <linux/capability.h>
50 #include <linux/compat.h>
51 #include <linux/vfs.h>
52 #include <linux/ptrace.h>
53 #include <linux/fadvise.h>
54 #include <linux/ipc.h>
55 
56 #include <asm/types.h>
57 #include <asm/uaccess.h>
58 
59 #include <net/scm.h>
60 #include <net/sock.h>
61 
62 #include "compat_linux.h"
63 
64 long psw_user32_bits	= (PSW_BASE32_BITS | PSW_MASK_DAT | PSW_ASC_HOME |
65 			   PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK |
66 			   PSW_MASK_PSTATE | PSW_DEFAULT_KEY);
67 long psw32_user_bits	= (PSW32_BASE_BITS | PSW32_MASK_DAT | PSW32_ASC_HOME |
68 			   PSW32_MASK_IO | PSW32_MASK_EXT | PSW32_MASK_MCHECK |
69 			   PSW32_MASK_PSTATE);
70 
71 /* For this source file, we want overflow handling. */
72 
73 #undef high2lowuid
74 #undef high2lowgid
75 #undef low2highuid
76 #undef low2highgid
77 #undef SET_UID16
78 #undef SET_GID16
79 #undef NEW_TO_OLD_UID
80 #undef NEW_TO_OLD_GID
81 #undef SET_OLDSTAT_UID
82 #undef SET_OLDSTAT_GID
83 #undef SET_STAT_UID
84 #undef SET_STAT_GID
85 
86 #define high2lowuid(uid) ((uid) > 65535) ? (u16)overflowuid : (u16)(uid)
87 #define high2lowgid(gid) ((gid) > 65535) ? (u16)overflowgid : (u16)(gid)
88 #define low2highuid(uid) ((uid) == (u16)-1) ? (uid_t)-1 : (uid_t)(uid)
89 #define low2highgid(gid) ((gid) == (u16)-1) ? (gid_t)-1 : (gid_t)(gid)
90 #define SET_UID16(var, uid)	var = high2lowuid(uid)
91 #define SET_GID16(var, gid)	var = high2lowgid(gid)
92 #define NEW_TO_OLD_UID(uid)	high2lowuid(uid)
93 #define NEW_TO_OLD_GID(gid)	high2lowgid(gid)
94 #define SET_OLDSTAT_UID(stat, uid)	(stat).st_uid = high2lowuid(uid)
95 #define SET_OLDSTAT_GID(stat, gid)	(stat).st_gid = high2lowgid(gid)
96 #define SET_STAT_UID(stat, uid)		(stat).st_uid = high2lowuid(uid)
97 #define SET_STAT_GID(stat, gid)		(stat).st_gid = high2lowgid(gid)
98 
99 asmlinkage long sys32_chown16(const char __user * filename, u16 user, u16 group)
100 {
101 	return sys_chown(filename, low2highuid(user), low2highgid(group));
102 }
103 
104 asmlinkage long sys32_lchown16(const char __user * filename, u16 user, u16 group)
105 {
106 	return sys_lchown(filename, low2highuid(user), low2highgid(group));
107 }
108 
109 asmlinkage long sys32_fchown16(unsigned int fd, u16 user, u16 group)
110 {
111 	return sys_fchown(fd, low2highuid(user), low2highgid(group));
112 }
113 
114 asmlinkage long sys32_setregid16(u16 rgid, u16 egid)
115 {
116 	return sys_setregid(low2highgid(rgid), low2highgid(egid));
117 }
118 
119 asmlinkage long sys32_setgid16(u16 gid)
120 {
121 	return sys_setgid((gid_t)gid);
122 }
123 
124 asmlinkage long sys32_setreuid16(u16 ruid, u16 euid)
125 {
126 	return sys_setreuid(low2highuid(ruid), low2highuid(euid));
127 }
128 
129 asmlinkage long sys32_setuid16(u16 uid)
130 {
131 	return sys_setuid((uid_t)uid);
132 }
133 
134 asmlinkage long sys32_setresuid16(u16 ruid, u16 euid, u16 suid)
135 {
136 	return sys_setresuid(low2highuid(ruid), low2highuid(euid),
137 		low2highuid(suid));
138 }
139 
140 asmlinkage long sys32_getresuid16(u16 __user *ruid, u16 __user *euid, u16 __user *suid)
141 {
142 	int retval;
143 
144 	if (!(retval = put_user(high2lowuid(current->cred->uid), ruid)) &&
145 	    !(retval = put_user(high2lowuid(current->cred->euid), euid)))
146 		retval = put_user(high2lowuid(current->cred->suid), suid);
147 
148 	return retval;
149 }
150 
151 asmlinkage long sys32_setresgid16(u16 rgid, u16 egid, u16 sgid)
152 {
153 	return sys_setresgid(low2highgid(rgid), low2highgid(egid),
154 		low2highgid(sgid));
155 }
156 
157 asmlinkage long sys32_getresgid16(u16 __user *rgid, u16 __user *egid, u16 __user *sgid)
158 {
159 	int retval;
160 
161 	if (!(retval = put_user(high2lowgid(current->cred->gid), rgid)) &&
162 	    !(retval = put_user(high2lowgid(current->cred->egid), egid)))
163 		retval = put_user(high2lowgid(current->cred->sgid), sgid);
164 
165 	return retval;
166 }
167 
168 asmlinkage long sys32_setfsuid16(u16 uid)
169 {
170 	return sys_setfsuid((uid_t)uid);
171 }
172 
173 asmlinkage long sys32_setfsgid16(u16 gid)
174 {
175 	return sys_setfsgid((gid_t)gid);
176 }
177 
178 static int groups16_to_user(u16 __user *grouplist, struct group_info *group_info)
179 {
180 	int i;
181 	u16 group;
182 
183 	for (i = 0; i < group_info->ngroups; i++) {
184 		group = (u16)GROUP_AT(group_info, i);
185 		if (put_user(group, grouplist+i))
186 			return -EFAULT;
187 	}
188 
189 	return 0;
190 }
191 
192 static int groups16_from_user(struct group_info *group_info, u16 __user *grouplist)
193 {
194 	int i;
195 	u16 group;
196 
197 	for (i = 0; i < group_info->ngroups; i++) {
198 		if (get_user(group, grouplist+i))
199 			return  -EFAULT;
200 		GROUP_AT(group_info, i) = (gid_t)group;
201 	}
202 
203 	return 0;
204 }
205 
206 asmlinkage long sys32_getgroups16(int gidsetsize, u16 __user *grouplist)
207 {
208 	int i;
209 
210 	if (gidsetsize < 0)
211 		return -EINVAL;
212 
213 	get_group_info(current->cred->group_info);
214 	i = current->cred->group_info->ngroups;
215 	if (gidsetsize) {
216 		if (i > gidsetsize) {
217 			i = -EINVAL;
218 			goto out;
219 		}
220 		if (groups16_to_user(grouplist, current->cred->group_info)) {
221 			i = -EFAULT;
222 			goto out;
223 		}
224 	}
225 out:
226 	put_group_info(current->cred->group_info);
227 	return i;
228 }
229 
230 asmlinkage long sys32_setgroups16(int gidsetsize, u16 __user *grouplist)
231 {
232 	struct group_info *group_info;
233 	int retval;
234 
235 	if (!capable(CAP_SETGID))
236 		return -EPERM;
237 	if ((unsigned)gidsetsize > NGROUPS_MAX)
238 		return -EINVAL;
239 
240 	group_info = groups_alloc(gidsetsize);
241 	if (!group_info)
242 		return -ENOMEM;
243 	retval = groups16_from_user(group_info, grouplist);
244 	if (retval) {
245 		put_group_info(group_info);
246 		return retval;
247 	}
248 
249 	retval = set_current_groups(group_info);
250 	put_group_info(group_info);
251 
252 	return retval;
253 }
254 
255 asmlinkage long sys32_getuid16(void)
256 {
257 	return high2lowuid(current->cred->uid);
258 }
259 
260 asmlinkage long sys32_geteuid16(void)
261 {
262 	return high2lowuid(current->cred->euid);
263 }
264 
265 asmlinkage long sys32_getgid16(void)
266 {
267 	return high2lowgid(current->cred->gid);
268 }
269 
270 asmlinkage long sys32_getegid16(void)
271 {
272 	return high2lowgid(current->cred->egid);
273 }
274 
275 /*
276  * sys32_ipc() is the de-multiplexer for the SysV IPC calls in 32bit emulation.
277  *
278  * This is really horribly ugly.
279  */
280 #ifdef CONFIG_SYSVIPC
281 asmlinkage long sys32_ipc(u32 call, int first, int second, int third, u32 ptr)
282 {
283 	if (call >> 16)		/* hack for backward compatibility */
284 		return -EINVAL;
285 
286 	call &= 0xffff;
287 
288 	switch (call) {
289 	case SEMTIMEDOP:
290 		return compat_sys_semtimedop(first, compat_ptr(ptr),
291 					     second, compat_ptr(third));
292 	case SEMOP:
293 		/* struct sembuf is the same on 32 and 64bit :)) */
294 		return sys_semtimedop(first, compat_ptr(ptr),
295 				      second, NULL);
296 	case SEMGET:
297 		return sys_semget(first, second, third);
298 	case SEMCTL:
299 		return compat_sys_semctl(first, second, third,
300 					 compat_ptr(ptr));
301 	case MSGSND:
302 		return compat_sys_msgsnd(first, second, third,
303 					 compat_ptr(ptr));
304 	case MSGRCV:
305 		return compat_sys_msgrcv(first, second, 0, third,
306 					 0, compat_ptr(ptr));
307 	case MSGGET:
308 		return sys_msgget((key_t) first, second);
309 	case MSGCTL:
310 		return compat_sys_msgctl(first, second, compat_ptr(ptr));
311 	case SHMAT:
312 		return compat_sys_shmat(first, second, third,
313 					0, compat_ptr(ptr));
314 	case SHMDT:
315 		return sys_shmdt(compat_ptr(ptr));
316 	case SHMGET:
317 		return sys_shmget(first, (unsigned)second, third);
318 	case SHMCTL:
319 		return compat_sys_shmctl(first, second, compat_ptr(ptr));
320 	}
321 
322 	return -ENOSYS;
323 }
324 #endif
325 
326 asmlinkage long sys32_truncate64(const char __user * path, unsigned long high, unsigned long low)
327 {
328 	if ((int)high < 0)
329 		return -EINVAL;
330 	else
331 		return sys_truncate(path, (high << 32) | low);
332 }
333 
334 asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long high, unsigned long low)
335 {
336 	if ((int)high < 0)
337 		return -EINVAL;
338 	else
339 		return sys_ftruncate(fd, (high << 32) | low);
340 }
341 
342 asmlinkage long sys32_sched_rr_get_interval(compat_pid_t pid,
343 				struct compat_timespec __user *interval)
344 {
345 	struct timespec t;
346 	int ret;
347 	mm_segment_t old_fs = get_fs ();
348 
349 	set_fs (KERNEL_DS);
350 	ret = sys_sched_rr_get_interval(pid,
351 					(struct timespec __force __user *) &t);
352 	set_fs (old_fs);
353 	if (put_compat_timespec(&t, interval))
354 		return -EFAULT;
355 	return ret;
356 }
357 
358 asmlinkage long sys32_rt_sigprocmask(int how, compat_sigset_t __user *set,
359 			compat_sigset_t __user *oset, size_t sigsetsize)
360 {
361 	sigset_t s;
362 	compat_sigset_t s32;
363 	int ret;
364 	mm_segment_t old_fs = get_fs();
365 
366 	if (set) {
367 		if (copy_from_user (&s32, set, sizeof(compat_sigset_t)))
368 			return -EFAULT;
369 		switch (_NSIG_WORDS) {
370 		case 4: s.sig[3] = s32.sig[6] | (((long)s32.sig[7]) << 32);
371 		case 3: s.sig[2] = s32.sig[4] | (((long)s32.sig[5]) << 32);
372 		case 2: s.sig[1] = s32.sig[2] | (((long)s32.sig[3]) << 32);
373 		case 1: s.sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
374 		}
375 	}
376 	set_fs (KERNEL_DS);
377 	ret = sys_rt_sigprocmask(how,
378 				 set ? (sigset_t __force __user *) &s : NULL,
379 				 oset ? (sigset_t __force __user *) &s : NULL,
380 				 sigsetsize);
381 	set_fs (old_fs);
382 	if (ret) return ret;
383 	if (oset) {
384 		switch (_NSIG_WORDS) {
385 		case 4: s32.sig[7] = (s.sig[3] >> 32); s32.sig[6] = s.sig[3];
386 		case 3: s32.sig[5] = (s.sig[2] >> 32); s32.sig[4] = s.sig[2];
387 		case 2: s32.sig[3] = (s.sig[1] >> 32); s32.sig[2] = s.sig[1];
388 		case 1: s32.sig[1] = (s.sig[0] >> 32); s32.sig[0] = s.sig[0];
389 		}
390 		if (copy_to_user (oset, &s32, sizeof(compat_sigset_t)))
391 			return -EFAULT;
392 	}
393 	return 0;
394 }
395 
396 asmlinkage long sys32_rt_sigpending(compat_sigset_t __user *set,
397 				size_t sigsetsize)
398 {
399 	sigset_t s;
400 	compat_sigset_t s32;
401 	int ret;
402 	mm_segment_t old_fs = get_fs();
403 
404 	set_fs (KERNEL_DS);
405 	ret = sys_rt_sigpending((sigset_t __force __user *) &s, sigsetsize);
406 	set_fs (old_fs);
407 	if (!ret) {
408 		switch (_NSIG_WORDS) {
409 		case 4: s32.sig[7] = (s.sig[3] >> 32); s32.sig[6] = s.sig[3];
410 		case 3: s32.sig[5] = (s.sig[2] >> 32); s32.sig[4] = s.sig[2];
411 		case 2: s32.sig[3] = (s.sig[1] >> 32); s32.sig[2] = s.sig[1];
412 		case 1: s32.sig[1] = (s.sig[0] >> 32); s32.sig[0] = s.sig[0];
413 		}
414 		if (copy_to_user (set, &s32, sizeof(compat_sigset_t)))
415 			return -EFAULT;
416 	}
417 	return ret;
418 }
419 
420 asmlinkage long
421 sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo)
422 {
423 	siginfo_t info;
424 	int ret;
425 	mm_segment_t old_fs = get_fs();
426 
427 	if (copy_siginfo_from_user32(&info, uinfo))
428 		return -EFAULT;
429 	set_fs (KERNEL_DS);
430 	ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __force __user *) &info);
431 	set_fs (old_fs);
432 	return ret;
433 }
434 
435 /*
436  * sys32_execve() executes a new program after the asm stub has set
437  * things up for us.  This should basically do what I want it to.
438  */
439 asmlinkage long sys32_execve(char __user *name, compat_uptr_t __user *argv,
440 			     compat_uptr_t __user *envp)
441 {
442 	struct pt_regs *regs = task_pt_regs(current);
443 	char *filename;
444 	long rc;
445 
446 	filename = getname(name);
447 	rc = PTR_ERR(filename);
448 	if (IS_ERR(filename))
449 		return rc;
450 	rc = compat_do_execve(filename, argv, envp, regs);
451 	if (rc)
452 		goto out;
453 	current->thread.fp_regs.fpc=0;
454 	asm volatile("sfpc %0,0" : : "d" (0));
455 	rc = regs->gprs[2];
456 out:
457 	putname(filename);
458 	return rc;
459 }
460 
461 asmlinkage long sys32_pread64(unsigned int fd, char __user *ubuf,
462 				size_t count, u32 poshi, u32 poslo)
463 {
464 	if ((compat_ssize_t) count < 0)
465 		return -EINVAL;
466 	return sys_pread64(fd, ubuf, count, ((loff_t)AA(poshi) << 32) | AA(poslo));
467 }
468 
469 asmlinkage long sys32_pwrite64(unsigned int fd, const char __user *ubuf,
470 				size_t count, u32 poshi, u32 poslo)
471 {
472 	if ((compat_ssize_t) count < 0)
473 		return -EINVAL;
474 	return sys_pwrite64(fd, ubuf, count, ((loff_t)AA(poshi) << 32) | AA(poslo));
475 }
476 
477 asmlinkage compat_ssize_t sys32_readahead(int fd, u32 offhi, u32 offlo, s32 count)
478 {
479 	return sys_readahead(fd, ((loff_t)AA(offhi) << 32) | AA(offlo), count);
480 }
481 
482 asmlinkage long sys32_sendfile(int out_fd, int in_fd, compat_off_t __user *offset, size_t count)
483 {
484 	mm_segment_t old_fs = get_fs();
485 	int ret;
486 	off_t of;
487 
488 	if (offset && get_user(of, offset))
489 		return -EFAULT;
490 
491 	set_fs(KERNEL_DS);
492 	ret = sys_sendfile(out_fd, in_fd,
493 			   offset ? (off_t __force __user *) &of : NULL, count);
494 	set_fs(old_fs);
495 
496 	if (offset && put_user(of, offset))
497 		return -EFAULT;
498 
499 	return ret;
500 }
501 
502 asmlinkage long sys32_sendfile64(int out_fd, int in_fd,
503 				compat_loff_t __user *offset, s32 count)
504 {
505 	mm_segment_t old_fs = get_fs();
506 	int ret;
507 	loff_t lof;
508 
509 	if (offset && get_user(lof, offset))
510 		return -EFAULT;
511 
512 	set_fs(KERNEL_DS);
513 	ret = sys_sendfile64(out_fd, in_fd,
514 			     offset ? (loff_t __force __user *) &lof : NULL,
515 			     count);
516 	set_fs(old_fs);
517 
518 	if (offset && put_user(lof, offset))
519 		return -EFAULT;
520 
521 	return ret;
522 }
523 
524 struct stat64_emu31 {
525 	unsigned long long  st_dev;
526 	unsigned int    __pad1;
527 #define STAT64_HAS_BROKEN_ST_INO        1
528 	u32             __st_ino;
529 	unsigned int    st_mode;
530 	unsigned int    st_nlink;
531 	u32             st_uid;
532 	u32             st_gid;
533 	unsigned long long  st_rdev;
534 	unsigned int    __pad3;
535 	long            st_size;
536 	u32             st_blksize;
537 	unsigned char   __pad4[4];
538 	u32             __pad5;     /* future possible st_blocks high bits */
539 	u32             st_blocks;  /* Number 512-byte blocks allocated. */
540 	u32             st_atime;
541 	u32             __pad6;
542 	u32             st_mtime;
543 	u32             __pad7;
544 	u32             st_ctime;
545 	u32             __pad8;     /* will be high 32 bits of ctime someday */
546 	unsigned long   st_ino;
547 };
548 
549 static int cp_stat64(struct stat64_emu31 __user *ubuf, struct kstat *stat)
550 {
551 	struct stat64_emu31 tmp;
552 
553 	memset(&tmp, 0, sizeof(tmp));
554 
555 	tmp.st_dev = huge_encode_dev(stat->dev);
556 	tmp.st_ino = stat->ino;
557 	tmp.__st_ino = (u32)stat->ino;
558 	tmp.st_mode = stat->mode;
559 	tmp.st_nlink = (unsigned int)stat->nlink;
560 	tmp.st_uid = stat->uid;
561 	tmp.st_gid = stat->gid;
562 	tmp.st_rdev = huge_encode_dev(stat->rdev);
563 	tmp.st_size = stat->size;
564 	tmp.st_blksize = (u32)stat->blksize;
565 	tmp.st_blocks = (u32)stat->blocks;
566 	tmp.st_atime = (u32)stat->atime.tv_sec;
567 	tmp.st_mtime = (u32)stat->mtime.tv_sec;
568 	tmp.st_ctime = (u32)stat->ctime.tv_sec;
569 
570 	return copy_to_user(ubuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
571 }
572 
573 asmlinkage long sys32_stat64(char __user * filename, struct stat64_emu31 __user * statbuf)
574 {
575 	struct kstat stat;
576 	int ret = vfs_stat(filename, &stat);
577 	if (!ret)
578 		ret = cp_stat64(statbuf, &stat);
579 	return ret;
580 }
581 
582 asmlinkage long sys32_lstat64(char __user * filename, struct stat64_emu31 __user * statbuf)
583 {
584 	struct kstat stat;
585 	int ret = vfs_lstat(filename, &stat);
586 	if (!ret)
587 		ret = cp_stat64(statbuf, &stat);
588 	return ret;
589 }
590 
591 asmlinkage long sys32_fstat64(unsigned long fd, struct stat64_emu31 __user * statbuf)
592 {
593 	struct kstat stat;
594 	int ret = vfs_fstat(fd, &stat);
595 	if (!ret)
596 		ret = cp_stat64(statbuf, &stat);
597 	return ret;
598 }
599 
600 asmlinkage long sys32_fstatat64(unsigned int dfd, char __user *filename,
601 				struct stat64_emu31 __user* statbuf, int flag)
602 {
603 	struct kstat stat;
604 	int error;
605 
606 	error = vfs_fstatat(dfd, filename, &stat, flag);
607 	if (error)
608 		return error;
609 	return cp_stat64(statbuf, &stat);
610 }
611 
612 /*
613  * Linux/i386 didn't use to be able to handle more than
614  * 4 system call parameters, so these system calls used a memory
615  * block for parameter passing..
616  */
617 
618 struct mmap_arg_struct_emu31 {
619 	u32	addr;
620 	u32	len;
621 	u32	prot;
622 	u32	flags;
623 	u32	fd;
624 	u32	offset;
625 };
626 
627 asmlinkage unsigned long
628 old32_mmap(struct mmap_arg_struct_emu31 __user *arg)
629 {
630 	struct mmap_arg_struct_emu31 a;
631 	int error = -EFAULT;
632 
633 	if (copy_from_user(&a, arg, sizeof(a)))
634 		goto out;
635 
636 	error = -EINVAL;
637 	if (a.offset & ~PAGE_MASK)
638 		goto out;
639 
640 	error = sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
641 			       a.offset >> PAGE_SHIFT);
642 out:
643 	return error;
644 }
645 
646 asmlinkage long
647 sys32_mmap2(struct mmap_arg_struct_emu31 __user *arg)
648 {
649 	struct mmap_arg_struct_emu31 a;
650 	int error = -EFAULT;
651 
652 	if (copy_from_user(&a, arg, sizeof(a)))
653 		goto out;
654 	error = sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
655 out:
656 	return error;
657 }
658 
659 asmlinkage long sys32_read(unsigned int fd, char __user * buf, size_t count)
660 {
661 	if ((compat_ssize_t) count < 0)
662 		return -EINVAL;
663 
664 	return sys_read(fd, buf, count);
665 }
666 
667 asmlinkage long sys32_write(unsigned int fd, char __user * buf, size_t count)
668 {
669 	if ((compat_ssize_t) count < 0)
670 		return -EINVAL;
671 
672 	return sys_write(fd, buf, count);
673 }
674 
675 /*
676  * 31 bit emulation wrapper functions for sys_fadvise64/fadvise64_64.
677  * These need to rewrite the advise values for POSIX_FADV_{DONTNEED,NOREUSE}
678  * because the 31 bit values differ from the 64 bit values.
679  */
680 
681 asmlinkage long
682 sys32_fadvise64(int fd, loff_t offset, size_t len, int advise)
683 {
684 	if (advise == 4)
685 		advise = POSIX_FADV_DONTNEED;
686 	else if (advise == 5)
687 		advise = POSIX_FADV_NOREUSE;
688 	return sys_fadvise64(fd, offset, len, advise);
689 }
690 
691 struct fadvise64_64_args {
692 	int fd;
693 	long long offset;
694 	long long len;
695 	int advice;
696 };
697 
698 asmlinkage long
699 sys32_fadvise64_64(struct fadvise64_64_args __user *args)
700 {
701 	struct fadvise64_64_args a;
702 
703 	if ( copy_from_user(&a, args, sizeof(a)) )
704 		return -EFAULT;
705 	if (a.advice == 4)
706 		a.advice = POSIX_FADV_DONTNEED;
707 	else if (a.advice == 5)
708 		a.advice = POSIX_FADV_NOREUSE;
709 	return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
710 }
711