xref: /freebsd/sys/amd64/linux32/linux32_machdep.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*-
2  * Copyright (c) 2004 Tim J. Robbins
3  * Copyright (c) 2002 Doug Rabson
4  * Copyright (c) 2000 Marcel Moolenaar
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer
12  *    in this position and unchanged.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/systm.h>
37 #include <sys/file.h>
38 #include <sys/fcntl.h>
39 #include <sys/clock.h>
40 #include <sys/imgact.h>
41 #include <sys/limits.h>
42 #include <sys/lock.h>
43 #include <sys/malloc.h>
44 #include <sys/mman.h>
45 #include <sys/mutex.h>
46 #include <sys/priv.h>
47 #include <sys/proc.h>
48 #include <sys/resource.h>
49 #include <sys/resourcevar.h>
50 #include <sys/sched.h>
51 #include <sys/syscallsubr.h>
52 #include <sys/sysproto.h>
53 #include <sys/unistd.h>
54 
55 #include <machine/frame.h>
56 #include <machine/pcb.h>
57 #include <machine/psl.h>
58 #include <machine/segments.h>
59 #include <machine/specialreg.h>
60 
61 #include <vm/vm.h>
62 #include <vm/pmap.h>
63 #include <vm/vm_extern.h>
64 #include <vm/vm_kern.h>
65 #include <vm/vm_map.h>
66 
67 #include <amd64/linux32/linux.h>
68 #include <amd64/linux32/linux32_proto.h>
69 #include <compat/linux/linux_ipc.h>
70 #include <compat/linux/linux_signal.h>
71 #include <compat/linux/linux_util.h>
72 #include <compat/linux/linux_emul.h>
73 
74 struct l_old_select_argv {
75 	l_int		nfds;
76 	l_uintptr_t	readfds;
77 	l_uintptr_t	writefds;
78 	l_uintptr_t	exceptfds;
79 	l_uintptr_t	timeout;
80 } __packed;
81 
82 int
83 linux_to_bsd_sigaltstack(int lsa)
84 {
85 	int bsa = 0;
86 
87 	if (lsa & LINUX_SS_DISABLE)
88 		bsa |= SS_DISABLE;
89 	if (lsa & LINUX_SS_ONSTACK)
90 		bsa |= SS_ONSTACK;
91 	return (bsa);
92 }
93 
94 int
95 bsd_to_linux_sigaltstack(int bsa)
96 {
97 	int lsa = 0;
98 
99 	if (bsa & SS_DISABLE)
100 		lsa |= LINUX_SS_DISABLE;
101 	if (bsa & SS_ONSTACK)
102 		lsa |= LINUX_SS_ONSTACK;
103 	return (lsa);
104 }
105 
106 /*
107  * Custom version of exec_copyin_args() so that we can translate
108  * the pointers.
109  */
110 static int
111 linux_exec_copyin_args(struct image_args *args, char *fname,
112     enum uio_seg segflg, char **argv, char **envv)
113 {
114 	char *argp, *envp;
115 	u_int32_t *p32, arg;
116 	size_t length;
117 	int error;
118 
119 	bzero(args, sizeof(*args));
120 	if (argv == NULL)
121 		return (EFAULT);
122 
123 	/*
124 	 * Allocate temporary demand zeroed space for argument and
125 	 *	environment strings
126 	 */
127 	args->buf = (char *)kmem_alloc_wait(exec_map,
128 	    PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
129 	if (args->buf == NULL)
130 		return (ENOMEM);
131 	args->begin_argv = args->buf;
132 	args->endp = args->begin_argv;
133 	args->stringspace = ARG_MAX;
134 
135 	args->fname = args->buf + ARG_MAX;
136 
137 	/*
138 	 * Copy the file name.
139 	 */
140 	error = (segflg == UIO_SYSSPACE) ?
141 	    copystr(fname, args->fname, PATH_MAX, &length) :
142 	    copyinstr(fname, args->fname, PATH_MAX, &length);
143 	if (error != 0)
144 		goto err_exit;
145 
146 	/*
147 	 * extract arguments first
148 	 */
149 	p32 = (u_int32_t *)argv;
150 	for (;;) {
151 		error = copyin(p32++, &arg, sizeof(arg));
152 		if (error)
153 			goto err_exit;
154 		if (arg == 0)
155 			break;
156 		argp = PTRIN(arg);
157 		error = copyinstr(argp, args->endp, args->stringspace, &length);
158 		if (error) {
159 			if (error == ENAMETOOLONG)
160 				error = E2BIG;
161 
162 			goto err_exit;
163 		}
164 		args->stringspace -= length;
165 		args->endp += length;
166 		args->argc++;
167 	}
168 
169 	args->begin_envv = args->endp;
170 
171 	/*
172 	 * extract environment strings
173 	 */
174 	if (envv) {
175 		p32 = (u_int32_t *)envv;
176 		for (;;) {
177 			error = copyin(p32++, &arg, sizeof(arg));
178 			if (error)
179 				goto err_exit;
180 			if (arg == 0)
181 				break;
182 			envp = PTRIN(arg);
183 			error = copyinstr(envp, args->endp, args->stringspace,
184 			    &length);
185 			if (error) {
186 				if (error == ENAMETOOLONG)
187 					error = E2BIG;
188 				goto err_exit;
189 			}
190 			args->stringspace -= length;
191 			args->endp += length;
192 			args->envc++;
193 		}
194 	}
195 
196 	return (0);
197 
198 err_exit:
199 	kmem_free_wakeup(exec_map, (vm_offset_t)args->buf,
200 	    PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
201 	args->buf = NULL;
202 	return (error);
203 }
204 
205 int
206 linux_execve(struct thread *td, struct linux_execve_args *args)
207 {
208 	struct image_args eargs;
209 	char *path;
210 	int error;
211 
212 	LCONVPATHEXIST(td, args->path, &path);
213 
214 #ifdef DEBUG
215 	if (ldebug(execve))
216 		printf(ARGS(execve, "%s"), path);
217 #endif
218 
219 	error = linux_exec_copyin_args(&eargs, path, UIO_SYSSPACE, args->argp,
220 	    args->envp);
221 	free(path, M_TEMP);
222 	if (error == 0)
223 		error = kern_execve(td, &eargs, NULL);
224 	if (error == 0)
225 		/* Linux process can execute FreeBSD one, do not attempt
226 		 * to create emuldata for such process using
227 		 * linux_proc_init, this leads to a panic on KASSERT
228 		 * because such process has p->p_emuldata == NULL.
229 		 */
230 	   	if (td->td_proc->p_sysent == &elf_linux_sysvec)
231 			error = linux_proc_init(td, 0, 0);
232 	return (error);
233 }
234 
235 CTASSERT(sizeof(struct l_iovec32) == 8);
236 
237 static int
238 linux32_copyinuio(struct l_iovec32 *iovp, l_ulong iovcnt, struct uio **uiop)
239 {
240 	struct l_iovec32 iov32;
241 	struct iovec *iov;
242 	struct uio *uio;
243 	uint32_t iovlen;
244 	int error, i;
245 
246 	*uiop = NULL;
247 	if (iovcnt > UIO_MAXIOV)
248 		return (EINVAL);
249 	iovlen = iovcnt * sizeof(struct iovec);
250 	uio = malloc(iovlen + sizeof(*uio), M_IOV, M_WAITOK);
251 	iov = (struct iovec *)(uio + 1);
252 	for (i = 0; i < iovcnt; i++) {
253 		error = copyin(&iovp[i], &iov32, sizeof(struct l_iovec32));
254 		if (error) {
255 			free(uio, M_IOV);
256 			return (error);
257 		}
258 		iov[i].iov_base = PTRIN(iov32.iov_base);
259 		iov[i].iov_len = iov32.iov_len;
260 	}
261 	uio->uio_iov = iov;
262 	uio->uio_iovcnt = iovcnt;
263 	uio->uio_segflg = UIO_USERSPACE;
264 	uio->uio_offset = -1;
265 	uio->uio_resid = 0;
266 	for (i = 0; i < iovcnt; i++) {
267 		if (iov->iov_len > INT_MAX - uio->uio_resid) {
268 			free(uio, M_IOV);
269 			return (EINVAL);
270 		}
271 		uio->uio_resid += iov->iov_len;
272 		iov++;
273 	}
274 	*uiop = uio;
275 	return (0);
276 }
277 
278 int
279 linux32_copyiniov(struct l_iovec32 *iovp32, l_ulong iovcnt, struct iovec **iovp,
280     int error)
281 {
282 	struct l_iovec32 iov32;
283 	struct iovec *iov;
284 	uint32_t iovlen;
285 	int i;
286 
287 	*iovp = NULL;
288 	if (iovcnt > UIO_MAXIOV)
289 		return (error);
290 	iovlen = iovcnt * sizeof(struct iovec);
291 	iov = malloc(iovlen, M_IOV, M_WAITOK);
292 	for (i = 0; i < iovcnt; i++) {
293 		error = copyin(&iovp32[i], &iov32, sizeof(struct l_iovec32));
294 		if (error) {
295 			free(iov, M_IOV);
296 			return (error);
297 		}
298 		iov[i].iov_base = PTRIN(iov32.iov_base);
299 		iov[i].iov_len = iov32.iov_len;
300 	}
301 	*iovp = iov;
302 	return(0);
303 
304 }
305 
306 int
307 linux_readv(struct thread *td, struct linux_readv_args *uap)
308 {
309 	struct uio *auio;
310 	int error;
311 
312 	error = linux32_copyinuio(uap->iovp, uap->iovcnt, &auio);
313 	if (error)
314 		return (error);
315 	error = kern_readv(td, uap->fd, auio);
316 	free(auio, M_IOV);
317 	return (error);
318 }
319 
320 int
321 linux_writev(struct thread *td, struct linux_writev_args *uap)
322 {
323 	struct uio *auio;
324 	int error;
325 
326 	error = linux32_copyinuio(uap->iovp, uap->iovcnt, &auio);
327 	if (error)
328 		return (error);
329 	error = kern_writev(td, uap->fd, auio);
330 	free(auio, M_IOV);
331 	return (error);
332 }
333 
334 struct l_ipc_kludge {
335 	l_uintptr_t msgp;
336 	l_long msgtyp;
337 } __packed;
338 
339 int
340 linux_ipc(struct thread *td, struct linux_ipc_args *args)
341 {
342 
343 	switch (args->what & 0xFFFF) {
344 	case LINUX_SEMOP: {
345 		struct linux_semop_args a;
346 
347 		a.semid = args->arg1;
348 		a.tsops = args->ptr;
349 		a.nsops = args->arg2;
350 		return (linux_semop(td, &a));
351 	}
352 	case LINUX_SEMGET: {
353 		struct linux_semget_args a;
354 
355 		a.key = args->arg1;
356 		a.nsems = args->arg2;
357 		a.semflg = args->arg3;
358 		return (linux_semget(td, &a));
359 	}
360 	case LINUX_SEMCTL: {
361 		struct linux_semctl_args a;
362 		int error;
363 
364 		a.semid = args->arg1;
365 		a.semnum = args->arg2;
366 		a.cmd = args->arg3;
367 		error = copyin(args->ptr, &a.arg, sizeof(a.arg));
368 		if (error)
369 			return (error);
370 		return (linux_semctl(td, &a));
371 	}
372 	case LINUX_MSGSND: {
373 		struct linux_msgsnd_args a;
374 
375 		a.msqid = args->arg1;
376 		a.msgp = args->ptr;
377 		a.msgsz = args->arg2;
378 		a.msgflg = args->arg3;
379 		return (linux_msgsnd(td, &a));
380 	}
381 	case LINUX_MSGRCV: {
382 		struct linux_msgrcv_args a;
383 
384 		a.msqid = args->arg1;
385 		a.msgsz = args->arg2;
386 		a.msgflg = args->arg3;
387 		if ((args->what >> 16) == 0) {
388 			struct l_ipc_kludge tmp;
389 			int error;
390 
391 			if (args->ptr == 0)
392 				return (EINVAL);
393 			error = copyin(args->ptr, &tmp, sizeof(tmp));
394 			if (error)
395 				return (error);
396 			a.msgp = PTRIN(tmp.msgp);
397 			a.msgtyp = tmp.msgtyp;
398 		} else {
399 			a.msgp = args->ptr;
400 			a.msgtyp = args->arg5;
401 		}
402 		return (linux_msgrcv(td, &a));
403 	}
404 	case LINUX_MSGGET: {
405 		struct linux_msgget_args a;
406 
407 		a.key = args->arg1;
408 		a.msgflg = args->arg2;
409 		return (linux_msgget(td, &a));
410 	}
411 	case LINUX_MSGCTL: {
412 		struct linux_msgctl_args a;
413 
414 		a.msqid = args->arg1;
415 		a.cmd = args->arg2;
416 		a.buf = args->ptr;
417 		return (linux_msgctl(td, &a));
418 	}
419 	case LINUX_SHMAT: {
420 		struct linux_shmat_args a;
421 
422 		a.shmid = args->arg1;
423 		a.shmaddr = args->ptr;
424 		a.shmflg = args->arg2;
425 		a.raddr = PTRIN((l_uint)args->arg3);
426 		return (linux_shmat(td, &a));
427 	}
428 	case LINUX_SHMDT: {
429 		struct linux_shmdt_args a;
430 
431 		a.shmaddr = args->ptr;
432 		return (linux_shmdt(td, &a));
433 	}
434 	case LINUX_SHMGET: {
435 		struct linux_shmget_args a;
436 
437 		a.key = args->arg1;
438 		a.size = args->arg2;
439 		a.shmflg = args->arg3;
440 		return (linux_shmget(td, &a));
441 	}
442 	case LINUX_SHMCTL: {
443 		struct linux_shmctl_args a;
444 
445 		a.shmid = args->arg1;
446 		a.cmd = args->arg2;
447 		a.buf = args->ptr;
448 		return (linux_shmctl(td, &a));
449 	}
450 	default:
451 		break;
452 	}
453 
454 	return (EINVAL);
455 }
456 
457 int
458 linux_old_select(struct thread *td, struct linux_old_select_args *args)
459 {
460 	struct l_old_select_argv linux_args;
461 	struct linux_select_args newsel;
462 	int error;
463 
464 #ifdef DEBUG
465 	if (ldebug(old_select))
466 		printf(ARGS(old_select, "%p"), args->ptr);
467 #endif
468 
469 	error = copyin(args->ptr, &linux_args, sizeof(linux_args));
470 	if (error)
471 		return (error);
472 
473 	newsel.nfds = linux_args.nfds;
474 	newsel.readfds = PTRIN(linux_args.readfds);
475 	newsel.writefds = PTRIN(linux_args.writefds);
476 	newsel.exceptfds = PTRIN(linux_args.exceptfds);
477 	newsel.timeout = PTRIN(linux_args.timeout);
478 	return (linux_select(td, &newsel));
479 }
480 
481 int
482 linux_fork(struct thread *td, struct linux_fork_args *args)
483 {
484 	int error;
485 	struct proc *p2;
486 	struct thread *td2;
487 
488 #ifdef DEBUG
489 	if (ldebug(fork))
490 		printf(ARGS(fork, ""));
491 #endif
492 
493 	if ((error = fork1(td, RFFDG | RFPROC | RFSTOPPED, 0, &p2)) != 0)
494 		return (error);
495 
496 	if (error == 0) {
497 		td->td_retval[0] = p2->p_pid;
498 		td->td_retval[1] = 0;
499 	}
500 
501 	if (td->td_retval[1] == 1)
502 		td->td_retval[0] = 0;
503 	error = linux_proc_init(td, td->td_retval[0], 0);
504 	if (error)
505 		return (error);
506 
507 	td2 = FIRST_THREAD_IN_PROC(p2);
508 
509 	/*
510 	 * Make this runnable after we are finished with it.
511 	 */
512 	thread_lock(td2);
513 	TD_SET_CAN_RUN(td2);
514 	sched_add(td2, SRQ_BORING);
515 	thread_unlock(td2);
516 
517 	return (0);
518 }
519 
520 int
521 linux_vfork(struct thread *td, struct linux_vfork_args *args)
522 {
523 	int error;
524 	struct proc *p2;
525 	struct thread *td2;
526 
527 #ifdef DEBUG
528 	if (ldebug(vfork))
529 		printf(ARGS(vfork, ""));
530 #endif
531 
532 	/* Exclude RFPPWAIT */
533 	if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFSTOPPED, 0, &p2)) != 0)
534 		return (error);
535 	if (error == 0) {
536 	   	td->td_retval[0] = p2->p_pid;
537 		td->td_retval[1] = 0;
538 	}
539 	/* Are we the child? */
540 	if (td->td_retval[1] == 1)
541 		td->td_retval[0] = 0;
542 	error = linux_proc_init(td, td->td_retval[0], 0);
543 	if (error)
544 		return (error);
545 
546 	PROC_LOCK(p2);
547 	p2->p_flag |= P_PPWAIT;
548 	PROC_UNLOCK(p2);
549 
550 	td2 = FIRST_THREAD_IN_PROC(p2);
551 
552 	/*
553 	 * Make this runnable after we are finished with it.
554 	 */
555 	thread_lock(td2);
556 	TD_SET_CAN_RUN(td2);
557 	sched_add(td2, SRQ_BORING);
558 	thread_unlock(td2);
559 
560 	/* wait for the children to exit, ie. emulate vfork */
561 	PROC_LOCK(p2);
562 	while (p2->p_flag & P_PPWAIT)
563 		cv_wait(&p2->p_pwait, &p2->p_mtx);
564 	PROC_UNLOCK(p2);
565 
566 	return (0);
567 }
568 
569 int
570 linux_clone(struct thread *td, struct linux_clone_args *args)
571 {
572 	int error, ff = RFPROC | RFSTOPPED;
573 	struct proc *p2;
574 	struct thread *td2;
575 	int exit_signal;
576 	struct linux_emuldata *em;
577 
578 #ifdef DEBUG
579 	if (ldebug(clone)) {
580 		printf(ARGS(clone, "flags %x, stack %p, parent tid: %p, "
581 		    "child tid: %p"), (unsigned)args->flags,
582 		    args->stack, args->parent_tidptr, args->child_tidptr);
583 	}
584 #endif
585 
586 	exit_signal = args->flags & 0x000000ff;
587 	if (LINUX_SIG_VALID(exit_signal)) {
588 		if (exit_signal <= LINUX_SIGTBLSZ)
589 			exit_signal =
590 			    linux_to_bsd_signal[_SIG_IDX(exit_signal)];
591 	} else if (exit_signal != 0)
592 		return (EINVAL);
593 
594 	if (args->flags & LINUX_CLONE_VM)
595 		ff |= RFMEM;
596 	if (args->flags & LINUX_CLONE_SIGHAND)
597 		ff |= RFSIGSHARE;
598 	/*
599 	 * XXX: In Linux, sharing of fs info (chroot/cwd/umask)
600 	 * and open files is independant.  In FreeBSD, its in one
601 	 * structure but in reality it does not cause any problems
602 	 * because both of these flags are usually set together.
603 	 */
604 	if (!(args->flags & (LINUX_CLONE_FILES | LINUX_CLONE_FS)))
605 		ff |= RFFDG;
606 
607 	/*
608 	 * Attempt to detect when linux_clone(2) is used for creating
609 	 * kernel threads. Unfortunately despite the existence of the
610 	 * CLONE_THREAD flag, version of linuxthreads package used in
611 	 * most popular distros as of beginning of 2005 doesn't make
612 	 * any use of it. Therefore, this detection relies on
613 	 * empirical observation that linuxthreads sets certain
614 	 * combination of flags, so that we can make more or less
615 	 * precise detection and notify the FreeBSD kernel that several
616 	 * processes are in fact part of the same threading group, so
617 	 * that special treatment is necessary for signal delivery
618 	 * between those processes and fd locking.
619 	 */
620 	if ((args->flags & 0xffffff00) == LINUX_THREADING_FLAGS)
621 		ff |= RFTHREAD;
622 
623 	if (args->flags & LINUX_CLONE_PARENT_SETTID)
624 		if (args->parent_tidptr == NULL)
625 			return (EINVAL);
626 
627 	error = fork1(td, ff, 0, &p2);
628 	if (error)
629 		return (error);
630 
631 	if (args->flags & (LINUX_CLONE_PARENT | LINUX_CLONE_THREAD)) {
632 	   	sx_xlock(&proctree_lock);
633 		PROC_LOCK(p2);
634 		proc_reparent(p2, td->td_proc->p_pptr);
635 		PROC_UNLOCK(p2);
636 		sx_xunlock(&proctree_lock);
637 	}
638 
639 	/* create the emuldata */
640 	error = linux_proc_init(td, p2->p_pid, args->flags);
641 	/* reference it - no need to check this */
642 	em = em_find(p2, EMUL_DOLOCK);
643 	KASSERT(em != NULL, ("clone: emuldata not found.\n"));
644 	/* and adjust it */
645 
646 	if (args->flags & LINUX_CLONE_THREAD) {
647 #ifdef notyet
648 	   	PROC_LOCK(p2);
649 	   	p2->p_pgrp = td->td_proc->p_pgrp;
650 	   	PROC_UNLOCK(p2);
651 #endif
652 		exit_signal = 0;
653 	}
654 
655 	if (args->flags & LINUX_CLONE_CHILD_SETTID)
656 		em->child_set_tid = args->child_tidptr;
657 	else
658 	   	em->child_set_tid = NULL;
659 
660 	if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
661 		em->child_clear_tid = args->child_tidptr;
662 	else
663 	   	em->child_clear_tid = NULL;
664 
665 	EMUL_UNLOCK(&emul_lock);
666 
667 	if (args->flags & LINUX_CLONE_PARENT_SETTID) {
668 		error = copyout(&p2->p_pid, args->parent_tidptr,
669 		    sizeof(p2->p_pid));
670 		if (error)
671 			printf(LMSG("copyout failed!"));
672 	}
673 
674 	PROC_LOCK(p2);
675 	p2->p_sigparent = exit_signal;
676 	PROC_UNLOCK(p2);
677 	td2 = FIRST_THREAD_IN_PROC(p2);
678 	/*
679 	 * In a case of stack = NULL, we are supposed to COW calling process
680 	 * stack. This is what normal fork() does, so we just keep tf_rsp arg
681 	 * intact.
682 	 */
683 	if (args->stack)
684 		td2->td_frame->tf_rsp = PTROUT(args->stack);
685 
686 	if (args->flags & LINUX_CLONE_SETTLS) {
687 		struct user_segment_descriptor sd;
688 		struct l_user_desc info;
689 		int a[2];
690 
691 		error = copyin((void *)td->td_frame->tf_rsi, &info,
692 		    sizeof(struct l_user_desc));
693 		if (error) {
694 			printf(LMSG("copyin failed!"));
695 		} else {
696 			/* We might copy out the entry_number as GUGS32_SEL. */
697 			info.entry_number = GUGS32_SEL;
698 			error = copyout(&info, (void *)td->td_frame->tf_rsi,
699 			    sizeof(struct l_user_desc));
700 			if (error)
701 				printf(LMSG("copyout failed!"));
702 
703 			a[0] = LINUX_LDT_entry_a(&info);
704 			a[1] = LINUX_LDT_entry_b(&info);
705 
706 			memcpy(&sd, &a, sizeof(a));
707 #ifdef DEBUG
708 			if (ldebug(clone))
709 				printf("Segment created in clone with "
710 				    "CLONE_SETTLS: lobase: %x, hibase: %x, "
711 				    "lolimit: %x, hilimit: %x, type: %i, "
712 				    "dpl: %i, p: %i, xx: %i, long: %i, "
713 				    "def32: %i, gran: %i\n", sd.sd_lobase,
714 				    sd.sd_hibase, sd.sd_lolimit, sd.sd_hilimit,
715 				    sd.sd_type, sd.sd_dpl, sd.sd_p, sd.sd_xx,
716 				    sd.sd_long, sd.sd_def32, sd.sd_gran);
717 #endif
718 			td2->td_pcb->pcb_gsbase = (register_t)info.base_addr;
719 			td2->td_pcb->pcb_gs32sd = sd;
720 			td2->td_pcb->pcb_gs = GSEL(GUGS32_SEL, SEL_UPL);
721 			td2->td_pcb->pcb_flags |= PCB_GS32BIT | PCB_32BIT;
722 		}
723 	}
724 
725 #ifdef DEBUG
726 	if (ldebug(clone))
727 		printf(LMSG("clone: successful rfork to %d, "
728 		    "stack %p sig = %d"), (int)p2->p_pid, args->stack,
729 		    exit_signal);
730 #endif
731 	if (args->flags & LINUX_CLONE_VFORK) {
732 	   	PROC_LOCK(p2);
733 	   	p2->p_flag |= P_PPWAIT;
734 	   	PROC_UNLOCK(p2);
735 	}
736 
737 	/*
738 	 * Make this runnable after we are finished with it.
739 	 */
740 	thread_lock(td2);
741 	TD_SET_CAN_RUN(td2);
742 	sched_add(td2, SRQ_BORING);
743 	thread_unlock(td2);
744 
745 	td->td_retval[0] = p2->p_pid;
746 	td->td_retval[1] = 0;
747 
748 	if (args->flags & LINUX_CLONE_VFORK) {
749 		/* wait for the children to exit, ie. emulate vfork */
750 		PROC_LOCK(p2);
751 		while (p2->p_flag & P_PPWAIT)
752 			cv_wait(&p2->p_pwait, &p2->p_mtx);
753 		PROC_UNLOCK(p2);
754 	}
755 
756 	return (0);
757 }
758 
759 #define STACK_SIZE  (2 * 1024 * 1024)
760 #define GUARD_SIZE  (4 * PAGE_SIZE)
761 
762 static int linux_mmap_common(struct thread *, struct l_mmap_argv *);
763 
764 int
765 linux_mmap2(struct thread *td, struct linux_mmap2_args *args)
766 {
767 	struct l_mmap_argv linux_args;
768 
769 #ifdef DEBUG
770 	if (ldebug(mmap2))
771 		printf(ARGS(mmap2, "0x%08x, %d, %d, 0x%08x, %d, %d"),
772 		    args->addr, args->len, args->prot,
773 		    args->flags, args->fd, args->pgoff);
774 #endif
775 
776 	linux_args.addr = PTROUT(args->addr);
777 	linux_args.len = args->len;
778 	linux_args.prot = args->prot;
779 	linux_args.flags = args->flags;
780 	linux_args.fd = args->fd;
781 	linux_args.pgoff = args->pgoff;
782 
783 	return (linux_mmap_common(td, &linux_args));
784 }
785 
786 int
787 linux_mmap(struct thread *td, struct linux_mmap_args *args)
788 {
789 	int error;
790 	struct l_mmap_argv linux_args;
791 
792 	error = copyin(args->ptr, &linux_args, sizeof(linux_args));
793 	if (error)
794 		return (error);
795 
796 #ifdef DEBUG
797 	if (ldebug(mmap))
798 		printf(ARGS(mmap, "0x%08x, %d, %d, 0x%08x, %d, %d"),
799 		    linux_args.addr, linux_args.len, linux_args.prot,
800 		    linux_args.flags, linux_args.fd, linux_args.pgoff);
801 #endif
802 	if ((linux_args.pgoff % PAGE_SIZE) != 0)
803 		return (EINVAL);
804 	linux_args.pgoff /= PAGE_SIZE;
805 
806 	return (linux_mmap_common(td, &linux_args));
807 }
808 
809 static int
810 linux_mmap_common(struct thread *td, struct l_mmap_argv *linux_args)
811 {
812 	struct proc *p = td->td_proc;
813 	struct mmap_args /* {
814 		caddr_t addr;
815 		size_t len;
816 		int prot;
817 		int flags;
818 		int fd;
819 		long pad;
820 		off_t pos;
821 	} */ bsd_args;
822 	int error;
823 	struct file *fp;
824 
825 	error = 0;
826 	bsd_args.flags = 0;
827 	fp = NULL;
828 
829 	/*
830 	 * Linux mmap(2):
831 	 * You must specify exactly one of MAP_SHARED and MAP_PRIVATE
832 	 */
833 	if (! ((linux_args->flags & LINUX_MAP_SHARED) ^
834 	    (linux_args->flags & LINUX_MAP_PRIVATE)))
835 		return (EINVAL);
836 
837 	if (linux_args->flags & LINUX_MAP_SHARED)
838 		bsd_args.flags |= MAP_SHARED;
839 	if (linux_args->flags & LINUX_MAP_PRIVATE)
840 		bsd_args.flags |= MAP_PRIVATE;
841 	if (linux_args->flags & LINUX_MAP_FIXED)
842 		bsd_args.flags |= MAP_FIXED;
843 	if (linux_args->flags & LINUX_MAP_ANON)
844 		bsd_args.flags |= MAP_ANON;
845 	else
846 		bsd_args.flags |= MAP_NOSYNC;
847 	if (linux_args->flags & LINUX_MAP_GROWSDOWN)
848 		bsd_args.flags |= MAP_STACK;
849 
850 	/*
851 	 * PROT_READ, PROT_WRITE, or PROT_EXEC implies PROT_READ and PROT_EXEC
852 	 * on Linux/i386. We do this to ensure maximum compatibility.
853 	 * Linux/ia64 does the same in i386 emulation mode.
854 	 */
855 	bsd_args.prot = linux_args->prot;
856 	if (bsd_args.prot & (PROT_READ | PROT_WRITE | PROT_EXEC))
857 		bsd_args.prot |= PROT_READ | PROT_EXEC;
858 
859 	/* Linux does not check file descriptor when MAP_ANONYMOUS is set. */
860 	bsd_args.fd = (bsd_args.flags & MAP_ANON) ? -1 : linux_args->fd;
861 	if (bsd_args.fd != -1) {
862 		/*
863 		 * Linux follows Solaris mmap(2) description:
864 		 * The file descriptor fildes is opened with
865 		 * read permission, regardless of the
866 		 * protection options specified.
867 		 */
868 
869 		if ((error = fget(td, bsd_args.fd, &fp)) != 0)
870 			return (error);
871 		if (fp->f_type != DTYPE_VNODE) {
872 			fdrop(fp, td);
873 			return (EINVAL);
874 		}
875 
876 		/* Linux mmap() just fails for O_WRONLY files */
877 		if (!(fp->f_flag & FREAD)) {
878 			fdrop(fp, td);
879 			return (EACCES);
880 		}
881 
882 		fdrop(fp, td);
883 	}
884 
885 	if (linux_args->flags & LINUX_MAP_GROWSDOWN) {
886 		/*
887 		 * The Linux MAP_GROWSDOWN option does not limit auto
888 		 * growth of the region.  Linux mmap with this option
889 		 * takes as addr the inital BOS, and as len, the initial
890 		 * region size.  It can then grow down from addr without
891 		 * limit.  However, Linux threads has an implicit internal
892 		 * limit to stack size of STACK_SIZE.  Its just not
893 		 * enforced explicitly in Linux.  But, here we impose
894 		 * a limit of (STACK_SIZE - GUARD_SIZE) on the stack
895 		 * region, since we can do this with our mmap.
896 		 *
897 		 * Our mmap with MAP_STACK takes addr as the maximum
898 		 * downsize limit on BOS, and as len the max size of
899 		 * the region.  It then maps the top SGROWSIZ bytes,
900 		 * and auto grows the region down, up to the limit
901 		 * in addr.
902 		 *
903 		 * If we don't use the MAP_STACK option, the effect
904 		 * of this code is to allocate a stack region of a
905 		 * fixed size of (STACK_SIZE - GUARD_SIZE).
906 		 */
907 
908 		if ((caddr_t)PTRIN(linux_args->addr) + linux_args->len >
909 		    p->p_vmspace->vm_maxsaddr) {
910 			/*
911 			 * Some Linux apps will attempt to mmap
912 			 * thread stacks near the top of their
913 			 * address space.  If their TOS is greater
914 			 * than vm_maxsaddr, vm_map_growstack()
915 			 * will confuse the thread stack with the
916 			 * process stack and deliver a SEGV if they
917 			 * attempt to grow the thread stack past their
918 			 * current stacksize rlimit.  To avoid this,
919 			 * adjust vm_maxsaddr upwards to reflect
920 			 * the current stacksize rlimit rather
921 			 * than the maximum possible stacksize.
922 			 * It would be better to adjust the
923 			 * mmap'ed region, but some apps do not check
924 			 * mmap's return value.
925 			 */
926 			PROC_LOCK(p);
927 			p->p_vmspace->vm_maxsaddr = (char *)LINUX32_USRSTACK -
928 			    lim_cur(p, RLIMIT_STACK);
929 			PROC_UNLOCK(p);
930 		}
931 
932 		/*
933 		 * This gives us our maximum stack size and a new BOS.
934 		 * If we're using VM_STACK, then mmap will just map
935 		 * the top SGROWSIZ bytes, and let the stack grow down
936 		 * to the limit at BOS.  If we're not using VM_STACK
937 		 * we map the full stack, since we don't have a way
938 		 * to autogrow it.
939 		 */
940 		if (linux_args->len > STACK_SIZE - GUARD_SIZE) {
941 			bsd_args.addr = (caddr_t)PTRIN(linux_args->addr);
942 			bsd_args.len = linux_args->len;
943 		} else {
944 			bsd_args.addr = (caddr_t)PTRIN(linux_args->addr) -
945 			    (STACK_SIZE - GUARD_SIZE - linux_args->len);
946 			bsd_args.len = STACK_SIZE - GUARD_SIZE;
947 		}
948 	} else {
949 		bsd_args.addr = (caddr_t)PTRIN(linux_args->addr);
950 		bsd_args.len  = linux_args->len;
951 	}
952 	bsd_args.pos = (off_t)linux_args->pgoff * PAGE_SIZE;
953 
954 #ifdef DEBUG
955 	if (ldebug(mmap))
956 		printf("-> %s(%p, %d, %d, 0x%08x, %d, 0x%x)\n",
957 		    __func__,
958 		    (void *)bsd_args.addr, (int)bsd_args.len, bsd_args.prot,
959 		    bsd_args.flags, bsd_args.fd, (int)bsd_args.pos);
960 #endif
961 	error = mmap(td, &bsd_args);
962 #ifdef DEBUG
963 	if (ldebug(mmap))
964 		printf("-> %s() return: 0x%x (0x%08x)\n",
965 			__func__, error, (u_int)td->td_retval[0]);
966 #endif
967 	return (error);
968 }
969 
970 int
971 linux_mprotect(struct thread *td, struct linux_mprotect_args *uap)
972 {
973 	struct mprotect_args bsd_args;
974 
975 	bsd_args.addr = uap->addr;
976 	bsd_args.len = uap->len;
977 	bsd_args.prot = uap->prot;
978 	if (bsd_args.prot & (PROT_READ | PROT_WRITE | PROT_EXEC))
979 		bsd_args.prot |= PROT_READ | PROT_EXEC;
980 	return (mprotect(td, &bsd_args));
981 }
982 
983 int
984 linux_iopl(struct thread *td, struct linux_iopl_args *args)
985 {
986 	int error;
987 
988 	if (args->level < 0 || args->level > 3)
989 		return (EINVAL);
990 	if ((error = priv_check(td, PRIV_IO)) != 0)
991 		return (error);
992 	if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
993 		return (error);
994 	td->td_frame->tf_rflags = (td->td_frame->tf_rflags & ~PSL_IOPL) |
995 	    (args->level * (PSL_IOPL / 3));
996 
997 	return (0);
998 }
999 
1000 int
1001 linux_pipe(struct thread *td, struct linux_pipe_args *args)
1002 {
1003 	int error;
1004 	int fildes[2];
1005 
1006 #ifdef DEBUG
1007 	if (ldebug(pipe))
1008 		printf(ARGS(pipe, "*"));
1009 #endif
1010 
1011 	error = kern_pipe(td, fildes);
1012 	if (error)
1013 		return (error);
1014 
1015 	/* XXX: Close descriptors on error. */
1016 	return (copyout(fildes, args->pipefds, sizeof fildes));
1017 }
1018 
1019 int
1020 linux_sigaction(struct thread *td, struct linux_sigaction_args *args)
1021 {
1022 	l_osigaction_t osa;
1023 	l_sigaction_t act, oact;
1024 	int error;
1025 
1026 #ifdef DEBUG
1027 	if (ldebug(sigaction))
1028 		printf(ARGS(sigaction, "%d, %p, %p"),
1029 		    args->sig, (void *)args->nsa, (void *)args->osa);
1030 #endif
1031 
1032 	if (args->nsa != NULL) {
1033 		error = copyin(args->nsa, &osa, sizeof(l_osigaction_t));
1034 		if (error)
1035 			return (error);
1036 		act.lsa_handler = osa.lsa_handler;
1037 		act.lsa_flags = osa.lsa_flags;
1038 		act.lsa_restorer = osa.lsa_restorer;
1039 		LINUX_SIGEMPTYSET(act.lsa_mask);
1040 		act.lsa_mask.__bits[0] = osa.lsa_mask;
1041 	}
1042 
1043 	error = linux_do_sigaction(td, args->sig, args->nsa ? &act : NULL,
1044 	    args->osa ? &oact : NULL);
1045 
1046 	if (args->osa != NULL && !error) {
1047 		osa.lsa_handler = oact.lsa_handler;
1048 		osa.lsa_flags = oact.lsa_flags;
1049 		osa.lsa_restorer = oact.lsa_restorer;
1050 		osa.lsa_mask = oact.lsa_mask.__bits[0];
1051 		error = copyout(&osa, args->osa, sizeof(l_osigaction_t));
1052 	}
1053 
1054 	return (error);
1055 }
1056 
1057 /*
1058  * Linux has two extra args, restart and oldmask.  We don't use these,
1059  * but it seems that "restart" is actually a context pointer that
1060  * enables the signal to happen with a different register set.
1061  */
1062 int
1063 linux_sigsuspend(struct thread *td, struct linux_sigsuspend_args *args)
1064 {
1065 	sigset_t sigmask;
1066 	l_sigset_t mask;
1067 
1068 #ifdef DEBUG
1069 	if (ldebug(sigsuspend))
1070 		printf(ARGS(sigsuspend, "%08lx"), (unsigned long)args->mask);
1071 #endif
1072 
1073 	LINUX_SIGEMPTYSET(mask);
1074 	mask.__bits[0] = args->mask;
1075 	linux_to_bsd_sigset(&mask, &sigmask);
1076 	return (kern_sigsuspend(td, sigmask));
1077 }
1078 
1079 int
1080 linux_rt_sigsuspend(struct thread *td, struct linux_rt_sigsuspend_args *uap)
1081 {
1082 	l_sigset_t lmask;
1083 	sigset_t sigmask;
1084 	int error;
1085 
1086 #ifdef DEBUG
1087 	if (ldebug(rt_sigsuspend))
1088 		printf(ARGS(rt_sigsuspend, "%p, %d"),
1089 		    (void *)uap->newset, uap->sigsetsize);
1090 #endif
1091 
1092 	if (uap->sigsetsize != sizeof(l_sigset_t))
1093 		return (EINVAL);
1094 
1095 	error = copyin(uap->newset, &lmask, sizeof(l_sigset_t));
1096 	if (error)
1097 		return (error);
1098 
1099 	linux_to_bsd_sigset(&lmask, &sigmask);
1100 	return (kern_sigsuspend(td, sigmask));
1101 }
1102 
1103 int
1104 linux_pause(struct thread *td, struct linux_pause_args *args)
1105 {
1106 	struct proc *p = td->td_proc;
1107 	sigset_t sigmask;
1108 
1109 #ifdef DEBUG
1110 	if (ldebug(pause))
1111 		printf(ARGS(pause, ""));
1112 #endif
1113 
1114 	PROC_LOCK(p);
1115 	sigmask = td->td_sigmask;
1116 	PROC_UNLOCK(p);
1117 	return (kern_sigsuspend(td, sigmask));
1118 }
1119 
1120 int
1121 linux_sigaltstack(struct thread *td, struct linux_sigaltstack_args *uap)
1122 {
1123 	stack_t ss, oss;
1124 	l_stack_t lss;
1125 	int error;
1126 
1127 #ifdef DEBUG
1128 	if (ldebug(sigaltstack))
1129 		printf(ARGS(sigaltstack, "%p, %p"), uap->uss, uap->uoss);
1130 #endif
1131 
1132 	if (uap->uss != NULL) {
1133 		error = copyin(uap->uss, &lss, sizeof(l_stack_t));
1134 		if (error)
1135 			return (error);
1136 
1137 		ss.ss_sp = PTRIN(lss.ss_sp);
1138 		ss.ss_size = lss.ss_size;
1139 		ss.ss_flags = linux_to_bsd_sigaltstack(lss.ss_flags);
1140 	}
1141 	error = kern_sigaltstack(td, (uap->uss != NULL) ? &ss : NULL,
1142 	    (uap->uoss != NULL) ? &oss : NULL);
1143 	if (!error && uap->uoss != NULL) {
1144 		lss.ss_sp = PTROUT(oss.ss_sp);
1145 		lss.ss_size = oss.ss_size;
1146 		lss.ss_flags = bsd_to_linux_sigaltstack(oss.ss_flags);
1147 		error = copyout(&lss, uap->uoss, sizeof(l_stack_t));
1148 	}
1149 
1150 	return (error);
1151 }
1152 
1153 int
1154 linux_ftruncate64(struct thread *td, struct linux_ftruncate64_args *args)
1155 {
1156 	struct ftruncate_args sa;
1157 
1158 #ifdef DEBUG
1159 	if (ldebug(ftruncate64))
1160 		printf(ARGS(ftruncate64, "%u, %jd"), args->fd,
1161 		    (intmax_t)args->length);
1162 #endif
1163 
1164 	sa.fd = args->fd;
1165 	sa.length = args->length;
1166 	return ftruncate(td, &sa);
1167 }
1168 
1169 int
1170 linux_gettimeofday(struct thread *td, struct linux_gettimeofday_args *uap)
1171 {
1172 	struct timeval atv;
1173 	l_timeval atv32;
1174 	struct timezone rtz;
1175 	int error = 0;
1176 
1177 	if (uap->tp) {
1178 		microtime(&atv);
1179 		atv32.tv_sec = atv.tv_sec;
1180 		atv32.tv_usec = atv.tv_usec;
1181 		error = copyout(&atv32, uap->tp, sizeof(atv32));
1182 	}
1183 	if (error == 0 && uap->tzp != NULL) {
1184 		rtz.tz_minuteswest = tz_minuteswest;
1185 		rtz.tz_dsttime = tz_dsttime;
1186 		error = copyout(&rtz, uap->tzp, sizeof(rtz));
1187 	}
1188 	return (error);
1189 }
1190 
1191 int
1192 linux_settimeofday(struct thread *td, struct linux_settimeofday_args *uap)
1193 {
1194 	l_timeval atv32;
1195 	struct timeval atv, *tvp;
1196 	struct timezone atz, *tzp;
1197 	int error;
1198 
1199 	if (uap->tp) {
1200 		error = copyin(uap->tp, &atv32, sizeof(atv32));
1201 		if (error)
1202 			return (error);
1203 		atv.tv_sec = atv32.tv_sec;
1204 		atv.tv_usec = atv32.tv_usec;
1205 		tvp = &atv;
1206 	} else
1207 		tvp = NULL;
1208 	if (uap->tzp) {
1209 		error = copyin(uap->tzp, &atz, sizeof(atz));
1210 		if (error)
1211 			return (error);
1212 		tzp = &atz;
1213 	} else
1214 		tzp = NULL;
1215 	return (kern_settimeofday(td, tvp, tzp));
1216 }
1217 
1218 int
1219 linux_getrusage(struct thread *td, struct linux_getrusage_args *uap)
1220 {
1221 	struct l_rusage s32;
1222 	struct rusage s;
1223 	int error;
1224 
1225 	error = kern_getrusage(td, uap->who, &s);
1226 	if (error != 0)
1227 		return (error);
1228 	if (uap->rusage != NULL) {
1229 		s32.ru_utime.tv_sec = s.ru_utime.tv_sec;
1230 		s32.ru_utime.tv_usec = s.ru_utime.tv_usec;
1231 		s32.ru_stime.tv_sec = s.ru_stime.tv_sec;
1232 		s32.ru_stime.tv_usec = s.ru_stime.tv_usec;
1233 		s32.ru_maxrss = s.ru_maxrss;
1234 		s32.ru_ixrss = s.ru_ixrss;
1235 		s32.ru_idrss = s.ru_idrss;
1236 		s32.ru_isrss = s.ru_isrss;
1237 		s32.ru_minflt = s.ru_minflt;
1238 		s32.ru_majflt = s.ru_majflt;
1239 		s32.ru_nswap = s.ru_nswap;
1240 		s32.ru_inblock = s.ru_inblock;
1241 		s32.ru_oublock = s.ru_oublock;
1242 		s32.ru_msgsnd = s.ru_msgsnd;
1243 		s32.ru_msgrcv = s.ru_msgrcv;
1244 		s32.ru_nsignals = s.ru_nsignals;
1245 		s32.ru_nvcsw = s.ru_nvcsw;
1246 		s32.ru_nivcsw = s.ru_nivcsw;
1247 		error = copyout(&s32, uap->rusage, sizeof(s32));
1248 	}
1249 	return (error);
1250 }
1251 
1252 int
1253 linux_sched_rr_get_interval(struct thread *td,
1254     struct linux_sched_rr_get_interval_args *uap)
1255 {
1256 	struct timespec ts;
1257 	struct l_timespec ts32;
1258 	int error;
1259 
1260 	error = kern_sched_rr_get_interval(td, uap->pid, &ts);
1261 	if (error != 0)
1262 		return (error);
1263 	ts32.tv_sec = ts.tv_sec;
1264 	ts32.tv_nsec = ts.tv_nsec;
1265 	return (copyout(&ts32, uap->interval, sizeof(ts32)));
1266 }
1267 
1268 int
1269 linux_set_thread_area(struct thread *td,
1270     struct linux_set_thread_area_args *args)
1271 {
1272 	struct l_user_desc info;
1273 	struct user_segment_descriptor sd;
1274 	int a[2];
1275 	int error;
1276 
1277 	error = copyin(args->desc, &info, sizeof(struct l_user_desc));
1278 	if (error)
1279 		return (error);
1280 
1281 #ifdef DEBUG
1282 	if (ldebug(set_thread_area))
1283 		printf(ARGS(set_thread_area, "%i, %x, %x, %i, %i, %i, "
1284 		    "%i, %i, %i"), info.entry_number, info.base_addr,
1285 		    info.limit, info.seg_32bit, info.contents,
1286 		    info.read_exec_only, info.limit_in_pages,
1287 		    info.seg_not_present, info.useable);
1288 #endif
1289 
1290 	/*
1291 	 * Semantics of Linux version: every thread in the system has array
1292 	 * of three TLS descriptors. 1st is GLIBC TLS, 2nd is WINE, 3rd unknown.
1293 	 * This syscall loads one of the selected TLS decriptors with a value
1294 	 * and also loads GDT descriptors 6, 7 and 8 with the content of
1295 	 * the per-thread descriptors.
1296 	 *
1297 	 * Semantics of FreeBSD version: I think we can ignore that Linux has
1298 	 * three per-thread descriptors and use just the first one.
1299 	 * The tls_array[] is used only in [gs]et_thread_area() syscalls and
1300 	 * for loading the GDT descriptors. We use just one GDT descriptor
1301 	 * for TLS, so we will load just one.
1302 	 *
1303 	 * XXX: This doesn't work when a user space process tries to use more
1304 	 * than one TLS segment. Comment in the Linux source says wine might
1305 	 * do this.
1306 	 */
1307 
1308 	/*
1309 	 * GLIBC reads current %gs and call set_thread_area() with it.
1310 	 * We should let GUDATA_SEL and GUGS32_SEL proceed as well because
1311 	 * we use these segments.
1312 	 */
1313 	switch (info.entry_number) {
1314 	case GUGS32_SEL:
1315 	case GUDATA_SEL:
1316 	case 6:
1317 	case -1:
1318 		info.entry_number = GUGS32_SEL;
1319 		break;
1320 	default:
1321 		return (EINVAL);
1322 	}
1323 
1324 	/*
1325 	 * We have to copy out the GDT entry we use.
1326 	 *
1327 	 * XXX: What if a user space program does not check the return value
1328 	 * and tries to use 6, 7 or 8?
1329 	 */
1330 	error = copyout(&info, args->desc, sizeof(struct l_user_desc));
1331 	if (error)
1332 		return (error);
1333 
1334 	if (LINUX_LDT_empty(&info)) {
1335 		a[0] = 0;
1336 		a[1] = 0;
1337 	} else {
1338 		a[0] = LINUX_LDT_entry_a(&info);
1339 		a[1] = LINUX_LDT_entry_b(&info);
1340 	}
1341 
1342 	memcpy(&sd, &a, sizeof(a));
1343 #ifdef DEBUG
1344 	if (ldebug(set_thread_area))
1345 		printf("Segment created in set_thread_area: "
1346 		    "lobase: %x, hibase: %x, lolimit: %x, hilimit: %x, "
1347 		    "type: %i, dpl: %i, p: %i, xx: %i, long: %i, "
1348 		    "def32: %i, gran: %i\n",
1349 		    sd.sd_lobase,
1350 		    sd.sd_hibase,
1351 		    sd.sd_lolimit,
1352 		    sd.sd_hilimit,
1353 		    sd.sd_type,
1354 		    sd.sd_dpl,
1355 		    sd.sd_p,
1356 		    sd.sd_xx,
1357 		    sd.sd_long,
1358 		    sd.sd_def32,
1359 		    sd.sd_gran);
1360 #endif
1361 
1362 	critical_enter();
1363 	td->td_pcb->pcb_gsbase = (register_t)info.base_addr;
1364 	td->td_pcb->pcb_gs32sd = *PCPU_GET(gs32p) = sd;
1365 	td->td_pcb->pcb_flags |= PCB_32BIT | PCB_GS32BIT;
1366 	wrmsr(MSR_KGSBASE, td->td_pcb->pcb_gsbase);
1367 	critical_exit();
1368 
1369 	return (0);
1370 }
1371