xref: /freebsd/sys/amd64/linux32/linux32_sysvec.c (revision 7661de35d15f582ab33e3bd6b8d909601557e436)
1 /*-
2  * Copyright (c) 2004 Tim J. Robbins
3  * Copyright (c) 2003 Peter Wemm
4  * Copyright (c) 2002 Doug Rabson
5  * Copyright (c) 1998-1999 Andrew Gallatin
6  * Copyright (c) 1994-1996 Søren Schmidt
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer
14  *    in this position and unchanged.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 #include "opt_compat.h"
36 
37 #ifndef COMPAT_FREEBSD32
38 #error "Unable to compile Linux-emulator due to missing COMPAT_FREEBSD32 option!"
39 #endif
40 
41 #define	__ELF_WORD_SIZE	32
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/exec.h>
46 #include <sys/fcntl.h>
47 #include <sys/imgact.h>
48 #include <sys/imgact_elf.h>
49 #include <sys/kernel.h>
50 #include <sys/lock.h>
51 #include <sys/malloc.h>
52 #include <sys/module.h>
53 #include <sys/mutex.h>
54 #include <sys/proc.h>
55 #include <sys/resourcevar.h>
56 #include <sys/signalvar.h>
57 #include <sys/sysctl.h>
58 #include <sys/syscallsubr.h>
59 #include <sys/sysent.h>
60 #include <sys/sysproto.h>
61 #include <sys/vnode.h>
62 #include <sys/eventhandler.h>
63 
64 #include <vm/vm.h>
65 #include <vm/pmap.h>
66 #include <vm/vm_extern.h>
67 #include <vm/vm_map.h>
68 #include <vm/vm_object.h>
69 #include <vm/vm_page.h>
70 #include <vm/vm_param.h>
71 
72 #include <machine/cpu.h>
73 #include <machine/md_var.h>
74 #include <machine/pcb.h>
75 #include <machine/specialreg.h>
76 
77 #include <amd64/linux32/linux.h>
78 #include <amd64/linux32/linux32_proto.h>
79 #include <compat/linux/linux_emul.h>
80 #include <compat/linux/linux_futex.h>
81 #include <compat/linux/linux_ioctl.h>
82 #include <compat/linux/linux_mib.h>
83 #include <compat/linux/linux_misc.h>
84 #include <compat/linux/linux_signal.h>
85 #include <compat/linux/linux_util.h>
86 
87 MODULE_VERSION(linux, 1);
88 
89 MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures");
90 
91 #define	AUXARGS_ENTRY_32(pos, id, val)	\
92 	do {				\
93 		suword32(pos++, id);	\
94 		suword32(pos++, val);	\
95 	} while (0)
96 
97 #if BYTE_ORDER == LITTLE_ENDIAN
98 #define SHELLMAGIC      0x2123 /* #! */
99 #else
100 #define SHELLMAGIC      0x2321
101 #endif
102 
103 /*
104  * Allow the sendsig functions to use the ldebug() facility
105  * even though they are not syscalls themselves. Map them
106  * to syscall 0. This is slightly less bogus than using
107  * ldebug(sigreturn).
108  */
109 #define	LINUX_SYS_linux_rt_sendsig	0
110 #define	LINUX_SYS_linux_sendsig		0
111 
112 const char *linux_platform = "i686";
113 static int linux_szplatform;
114 extern char linux_sigcode[];
115 extern int linux_szsigcode;
116 
117 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
118 
119 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
120 SET_DECLARE(linux_device_handler_set, struct linux_device_handler);
121 
122 static int	elf_linux_fixup(register_t **stack_base,
123 		    struct image_params *iparams);
124 static register_t *linux_copyout_strings(struct image_params *imgp);
125 static void     linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);
126 static void	exec_linux_setregs(struct thread *td,
127 				   struct image_params *imgp, u_long stack);
128 static void	linux32_fixlimit(struct rlimit *rl, int which);
129 static boolean_t linux32_trans_osrel(const Elf_Note *note, int32_t *osrel);
130 
131 static eventhandler_tag linux_exit_tag;
132 static eventhandler_tag linux_exec_tag;
133 
134 /*
135  * Linux syscalls return negative errno's, we do positive and map them
136  * Reference:
137  *   FreeBSD: src/sys/sys/errno.h
138  *   Linux:   linux-2.6.17.8/include/asm-generic/errno-base.h
139  *            linux-2.6.17.8/include/asm-generic/errno.h
140  */
141 static int bsd_to_linux_errno[ELAST + 1] = {
142 	-0,  -1,  -2,  -3,  -4,  -5,  -6,  -7,  -8,  -9,
143 	-10, -35, -12, -13, -14, -15, -16, -17, -18, -19,
144 	-20, -21, -22, -23, -24, -25, -26, -27, -28, -29,
145 	-30, -31, -32, -33, -34, -11,-115,-114, -88, -89,
146 	-90, -91, -92, -93, -94, -95, -96, -97, -98, -99,
147 	-100,-101,-102,-103,-104,-105,-106,-107,-108,-109,
148 	-110,-111, -40, -36,-112,-113, -39, -11, -87,-122,
149 	-116, -66,  -6,  -6,  -6,  -6,  -6, -37, -38,  -9,
150 	  -6,  -6, -43, -42, -75,-125, -84, -95, -16, -74,
151 	 -72, -67, -71
152 };
153 
154 int bsd_to_linux_signal[LINUX_SIGTBLSZ] = {
155 	LINUX_SIGHUP, LINUX_SIGINT, LINUX_SIGQUIT, LINUX_SIGILL,
156 	LINUX_SIGTRAP, LINUX_SIGABRT, 0, LINUX_SIGFPE,
157 	LINUX_SIGKILL, LINUX_SIGBUS, LINUX_SIGSEGV, LINUX_SIGSYS,
158 	LINUX_SIGPIPE, LINUX_SIGALRM, LINUX_SIGTERM, LINUX_SIGURG,
159 	LINUX_SIGSTOP, LINUX_SIGTSTP, LINUX_SIGCONT, LINUX_SIGCHLD,
160 	LINUX_SIGTTIN, LINUX_SIGTTOU, LINUX_SIGIO, LINUX_SIGXCPU,
161 	LINUX_SIGXFSZ, LINUX_SIGVTALRM, LINUX_SIGPROF, LINUX_SIGWINCH,
162 	0, LINUX_SIGUSR1, LINUX_SIGUSR2
163 };
164 
165 int linux_to_bsd_signal[LINUX_SIGTBLSZ] = {
166 	SIGHUP, SIGINT, SIGQUIT, SIGILL,
167 	SIGTRAP, SIGABRT, SIGBUS, SIGFPE,
168 	SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2,
169 	SIGPIPE, SIGALRM, SIGTERM, SIGBUS,
170 	SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP,
171 	SIGTTIN, SIGTTOU, SIGURG, SIGXCPU,
172 	SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH,
173 	SIGIO, SIGURG, SIGSYS
174 };
175 
176 #define LINUX_T_UNKNOWN  255
177 static int _bsd_to_linux_trapcode[] = {
178 	LINUX_T_UNKNOWN,	/* 0 */
179 	6,			/* 1  T_PRIVINFLT */
180 	LINUX_T_UNKNOWN,	/* 2 */
181 	3,			/* 3  T_BPTFLT */
182 	LINUX_T_UNKNOWN,	/* 4 */
183 	LINUX_T_UNKNOWN,	/* 5 */
184 	16,			/* 6  T_ARITHTRAP */
185 	254,			/* 7  T_ASTFLT */
186 	LINUX_T_UNKNOWN,	/* 8 */
187 	13,			/* 9  T_PROTFLT */
188 	1,			/* 10 T_TRCTRAP */
189 	LINUX_T_UNKNOWN,	/* 11 */
190 	14,			/* 12 T_PAGEFLT */
191 	LINUX_T_UNKNOWN,	/* 13 */
192 	17,			/* 14 T_ALIGNFLT */
193 	LINUX_T_UNKNOWN,	/* 15 */
194 	LINUX_T_UNKNOWN,	/* 16 */
195 	LINUX_T_UNKNOWN,	/* 17 */
196 	0,			/* 18 T_DIVIDE */
197 	2,			/* 19 T_NMI */
198 	4,			/* 20 T_OFLOW */
199 	5,			/* 21 T_BOUND */
200 	7,			/* 22 T_DNA */
201 	8,			/* 23 T_DOUBLEFLT */
202 	9,			/* 24 T_FPOPFLT */
203 	10,			/* 25 T_TSSFLT */
204 	11,			/* 26 T_SEGNPFLT */
205 	12,			/* 27 T_STKFLT */
206 	18,			/* 28 T_MCHK */
207 	19,			/* 29 T_XMMFLT */
208 	15			/* 30 T_RESERVED */
209 };
210 #define bsd_to_linux_trapcode(code) \
211     ((code)<sizeof(_bsd_to_linux_trapcode)/sizeof(*_bsd_to_linux_trapcode)? \
212      _bsd_to_linux_trapcode[(code)]: \
213      LINUX_T_UNKNOWN)
214 
215 struct linux32_ps_strings {
216 	u_int32_t ps_argvstr;	/* first of 0 or more argument strings */
217 	u_int ps_nargvstr;	/* the number of argument strings */
218 	u_int32_t ps_envstr;	/* first of 0 or more environment strings */
219 	u_int ps_nenvstr;	/* the number of environment strings */
220 };
221 
222 /*
223  * If FreeBSD & Linux have a difference of opinion about what a trap
224  * means, deal with it here.
225  *
226  * MPSAFE
227  */
228 static int
229 translate_traps(int signal, int trap_code)
230 {
231 	if (signal != SIGBUS)
232 		return signal;
233 	switch (trap_code) {
234 	case T_PROTFLT:
235 	case T_TSSFLT:
236 	case T_DOUBLEFLT:
237 	case T_PAGEFLT:
238 		return SIGSEGV;
239 	default:
240 		return signal;
241 	}
242 }
243 
244 static int
245 elf_linux_fixup(register_t **stack_base, struct image_params *imgp)
246 {
247 	Elf32_Auxargs *args;
248 	Elf32_Addr *base;
249 	Elf32_Addr *pos, *uplatform;
250 	struct linux32_ps_strings *arginfo;
251 
252 	arginfo = (struct linux32_ps_strings *)LINUX32_PS_STRINGS;
253 	uplatform = (Elf32_Addr *)((caddr_t)arginfo - linux_szplatform);
254 
255 	KASSERT(curthread->td_proc == imgp->proc,
256 	    ("unsafe elf_linux_fixup(), should be curproc"));
257 	base = (Elf32_Addr *)*stack_base;
258 	args = (Elf32_Auxargs *)imgp->auxargs;
259 	pos = base + (imgp->args->argc + imgp->args->envc + 2);
260 
261 	AUXARGS_ENTRY_32(pos, LINUX_AT_HWCAP, cpu_feature);
262 
263 	/*
264 	 * Do not export AT_CLKTCK when emulating Linux kernel prior to 2.4.0,
265 	 * as it has appeared in the 2.4.0-rc7 first time.
266 	 * Being exported, AT_CLKTCK is returned by sysconf(_SC_CLK_TCK),
267 	 * glibc falls back to the hard-coded CLK_TCK value when aux entry
268 	 * is not present.
269 	 * Also see linux_times() implementation.
270 	 */
271 	if (linux_kernver(curthread) >= LINUX_KERNVER_2004000)
272 		AUXARGS_ENTRY_32(pos, LINUX_AT_CLKTCK, stclohz);
273 	AUXARGS_ENTRY_32(pos, AT_PHDR, args->phdr);
274 	AUXARGS_ENTRY_32(pos, AT_PHENT, args->phent);
275 	AUXARGS_ENTRY_32(pos, AT_PHNUM, args->phnum);
276 	AUXARGS_ENTRY_32(pos, AT_PAGESZ, args->pagesz);
277 	AUXARGS_ENTRY_32(pos, AT_FLAGS, args->flags);
278 	AUXARGS_ENTRY_32(pos, AT_ENTRY, args->entry);
279 	AUXARGS_ENTRY_32(pos, AT_BASE, args->base);
280 	AUXARGS_ENTRY_32(pos, LINUX_AT_SECURE, 0);
281 	AUXARGS_ENTRY_32(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
282 	AUXARGS_ENTRY_32(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
283 	AUXARGS_ENTRY_32(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
284 	AUXARGS_ENTRY_32(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
285 	AUXARGS_ENTRY_32(pos, LINUX_AT_PLATFORM, PTROUT(uplatform));
286 	if (args->execfd != -1)
287 		AUXARGS_ENTRY_32(pos, AT_EXECFD, args->execfd);
288 	AUXARGS_ENTRY_32(pos, AT_NULL, 0);
289 
290 	free(imgp->auxargs, M_TEMP);
291 	imgp->auxargs = NULL;
292 
293 	base--;
294 	suword32(base, (uint32_t)imgp->args->argc);
295 	*stack_base = (register_t *)base;
296 	return 0;
297 }
298 
299 extern unsigned long linux_sznonrtsigcode;
300 
301 static void
302 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
303 {
304 	struct thread *td = curthread;
305 	struct proc *p = td->td_proc;
306 	struct sigacts *psp;
307 	struct trapframe *regs;
308 	struct l_rt_sigframe *fp, frame;
309 	int oonstack;
310 	int sig;
311 	int code;
312 
313 	sig = ksi->ksi_signo;
314 	code = ksi->ksi_code;
315 	PROC_LOCK_ASSERT(p, MA_OWNED);
316 	psp = p->p_sigacts;
317 	mtx_assert(&psp->ps_mtx, MA_OWNED);
318 	regs = td->td_frame;
319 	oonstack = sigonstack(regs->tf_rsp);
320 
321 #ifdef DEBUG
322 	if (ldebug(rt_sendsig))
323 		printf(ARGS(rt_sendsig, "%p, %d, %p, %u"),
324 		    catcher, sig, (void*)mask, code);
325 #endif
326 	/*
327 	 * Allocate space for the signal handler context.
328 	 */
329 	if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
330 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
331 		fp = (struct l_rt_sigframe *)(td->td_sigstk.ss_sp +
332 		    td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe));
333 	} else
334 		fp = (struct l_rt_sigframe *)regs->tf_rsp - 1;
335 	mtx_unlock(&psp->ps_mtx);
336 
337 	/*
338 	 * Build the argument list for the signal handler.
339 	 */
340 	if (p->p_sysent->sv_sigtbl)
341 		if (sig <= p->p_sysent->sv_sigsize)
342 			sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
343 
344 	bzero(&frame, sizeof(frame));
345 
346 	frame.sf_handler = PTROUT(catcher);
347 	frame.sf_sig = sig;
348 	frame.sf_siginfo = PTROUT(&fp->sf_si);
349 	frame.sf_ucontext = PTROUT(&fp->sf_sc);
350 
351 	/* Fill in POSIX parts */
352 	ksiginfo_to_lsiginfo(ksi, &frame.sf_si, sig);
353 
354 	/*
355 	 * Build the signal context to be used by sigreturn.
356 	 */
357 	frame.sf_sc.uc_flags = 0;		/* XXX ??? */
358 	frame.sf_sc.uc_link = 0;		/* XXX ??? */
359 
360 	frame.sf_sc.uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
361 	frame.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size;
362 	frame.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
363 	    ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
364 	PROC_UNLOCK(p);
365 
366 	bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask);
367 
368 	frame.sf_sc.uc_mcontext.sc_mask   = frame.sf_sc.uc_sigmask.__bits[0];
369 	frame.sf_sc.uc_mcontext.sc_edi    = regs->tf_rdi;
370 	frame.sf_sc.uc_mcontext.sc_esi    = regs->tf_rsi;
371 	frame.sf_sc.uc_mcontext.sc_ebp    = regs->tf_rbp;
372 	frame.sf_sc.uc_mcontext.sc_ebx    = regs->tf_rbx;
373 	frame.sf_sc.uc_mcontext.sc_edx    = regs->tf_rdx;
374 	frame.sf_sc.uc_mcontext.sc_ecx    = regs->tf_rcx;
375 	frame.sf_sc.uc_mcontext.sc_eax    = regs->tf_rax;
376 	frame.sf_sc.uc_mcontext.sc_eip    = regs->tf_rip;
377 	frame.sf_sc.uc_mcontext.sc_cs     = regs->tf_cs;
378 	frame.sf_sc.uc_mcontext.sc_gs     = regs->tf_gs;
379 	frame.sf_sc.uc_mcontext.sc_fs     = regs->tf_fs;
380 	frame.sf_sc.uc_mcontext.sc_es     = regs->tf_es;
381 	frame.sf_sc.uc_mcontext.sc_ds     = regs->tf_ds;
382 	frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_rflags;
383 	frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_rsp;
384 	frame.sf_sc.uc_mcontext.sc_ss     = regs->tf_ss;
385 	frame.sf_sc.uc_mcontext.sc_err    = regs->tf_err;
386 	frame.sf_sc.uc_mcontext.sc_cr2    = (u_int32_t)(uintptr_t)ksi->ksi_addr;
387 	frame.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code);
388 
389 #ifdef DEBUG
390 	if (ldebug(rt_sendsig))
391 		printf(LMSG("rt_sendsig flags: 0x%x, sp: %p, ss: 0x%lx, mask: 0x%x"),
392 		    frame.sf_sc.uc_stack.ss_flags, td->td_sigstk.ss_sp,
393 		    td->td_sigstk.ss_size, frame.sf_sc.uc_mcontext.sc_mask);
394 #endif
395 
396 	if (copyout(&frame, fp, sizeof(frame)) != 0) {
397 		/*
398 		 * Process has trashed its stack; give it an illegal
399 		 * instruction to halt it in its tracks.
400 		 */
401 #ifdef DEBUG
402 		if (ldebug(rt_sendsig))
403 			printf(LMSG("rt_sendsig: bad stack %p, oonstack=%x"),
404 			    fp, oonstack);
405 #endif
406 		PROC_LOCK(p);
407 		sigexit(td, SIGILL);
408 	}
409 
410 	/*
411 	 * Build context to run handler in.
412 	 */
413 	regs->tf_rsp = PTROUT(fp);
414 	regs->tf_rip = p->p_sysent->sv_sigcode_base + linux_sznonrtsigcode;
415 	regs->tf_rflags &= ~(PSL_T | PSL_D);
416 	regs->tf_cs = _ucode32sel;
417 	regs->tf_ss = _udatasel;
418 	regs->tf_ds = _udatasel;
419 	regs->tf_es = _udatasel;
420 	regs->tf_fs = _ufssel;
421 	regs->tf_gs = _ugssel;
422 	regs->tf_flags = TF_HASSEGS;
423 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
424 	PROC_LOCK(p);
425 	mtx_lock(&psp->ps_mtx);
426 }
427 
428 
429 /*
430  * Send an interrupt to process.
431  *
432  * Stack is set up to allow sigcode stored
433  * in u. to call routine, followed by kcall
434  * to sigreturn routine below.  After sigreturn
435  * resets the signal mask, the stack, and the
436  * frame pointer, it returns to the user
437  * specified pc, psl.
438  */
439 static void
440 linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
441 {
442 	struct thread *td = curthread;
443 	struct proc *p = td->td_proc;
444 	struct sigacts *psp;
445 	struct trapframe *regs;
446 	struct l_sigframe *fp, frame;
447 	l_sigset_t lmask;
448 	int oonstack, i;
449 	int sig, code;
450 
451 	sig = ksi->ksi_signo;
452 	code = ksi->ksi_code;
453 	PROC_LOCK_ASSERT(p, MA_OWNED);
454 	psp = p->p_sigacts;
455 	mtx_assert(&psp->ps_mtx, MA_OWNED);
456 	if (SIGISMEMBER(psp->ps_siginfo, sig)) {
457 		/* Signal handler installed with SA_SIGINFO. */
458 		linux_rt_sendsig(catcher, ksi, mask);
459 		return;
460 	}
461 
462 	regs = td->td_frame;
463 	oonstack = sigonstack(regs->tf_rsp);
464 
465 #ifdef DEBUG
466 	if (ldebug(sendsig))
467 		printf(ARGS(sendsig, "%p, %d, %p, %u"),
468 		    catcher, sig, (void*)mask, code);
469 #endif
470 
471 	/*
472 	 * Allocate space for the signal handler context.
473 	 */
474 	if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
475 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
476 		fp = (struct l_sigframe *)(td->td_sigstk.ss_sp +
477 		    td->td_sigstk.ss_size - sizeof(struct l_sigframe));
478 	} else
479 		fp = (struct l_sigframe *)regs->tf_rsp - 1;
480 	mtx_unlock(&psp->ps_mtx);
481 	PROC_UNLOCK(p);
482 
483 	/*
484 	 * Build the argument list for the signal handler.
485 	 */
486 	if (p->p_sysent->sv_sigtbl)
487 		if (sig <= p->p_sysent->sv_sigsize)
488 			sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
489 
490 	bzero(&frame, sizeof(frame));
491 
492 	frame.sf_handler = PTROUT(catcher);
493 	frame.sf_sig = sig;
494 
495 	bsd_to_linux_sigset(mask, &lmask);
496 
497 	/*
498 	 * Build the signal context to be used by sigreturn.
499 	 */
500 	frame.sf_sc.sc_mask   = lmask.__bits[0];
501 	frame.sf_sc.sc_gs     = regs->tf_gs;
502 	frame.sf_sc.sc_fs     = regs->tf_fs;
503 	frame.sf_sc.sc_es     = regs->tf_es;
504 	frame.sf_sc.sc_ds     = regs->tf_ds;
505 	frame.sf_sc.sc_edi    = regs->tf_rdi;
506 	frame.sf_sc.sc_esi    = regs->tf_rsi;
507 	frame.sf_sc.sc_ebp    = regs->tf_rbp;
508 	frame.sf_sc.sc_ebx    = regs->tf_rbx;
509 	frame.sf_sc.sc_edx    = regs->tf_rdx;
510 	frame.sf_sc.sc_ecx    = regs->tf_rcx;
511 	frame.sf_sc.sc_eax    = regs->tf_rax;
512 	frame.sf_sc.sc_eip    = regs->tf_rip;
513 	frame.sf_sc.sc_cs     = regs->tf_cs;
514 	frame.sf_sc.sc_eflags = regs->tf_rflags;
515 	frame.sf_sc.sc_esp_at_signal = regs->tf_rsp;
516 	frame.sf_sc.sc_ss     = regs->tf_ss;
517 	frame.sf_sc.sc_err    = regs->tf_err;
518 	frame.sf_sc.sc_cr2    = (u_int32_t)(uintptr_t)ksi->ksi_addr;
519 	frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(code);
520 
521 	for (i = 0; i < (LINUX_NSIG_WORDS-1); i++)
522 		frame.sf_extramask[i] = lmask.__bits[i+1];
523 
524 	if (copyout(&frame, fp, sizeof(frame)) != 0) {
525 		/*
526 		 * Process has trashed its stack; give it an illegal
527 		 * instruction to halt it in its tracks.
528 		 */
529 		PROC_LOCK(p);
530 		sigexit(td, SIGILL);
531 	}
532 
533 	/*
534 	 * Build context to run handler in.
535 	 */
536 	regs->tf_rsp = PTROUT(fp);
537 	regs->tf_rip = p->p_sysent->sv_sigcode_base;
538 	regs->tf_rflags &= ~(PSL_T | PSL_D);
539 	regs->tf_cs = _ucode32sel;
540 	regs->tf_ss = _udatasel;
541 	regs->tf_ds = _udatasel;
542 	regs->tf_es = _udatasel;
543 	regs->tf_fs = _ufssel;
544 	regs->tf_gs = _ugssel;
545 	regs->tf_flags = TF_HASSEGS;
546 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
547 	PROC_LOCK(p);
548 	mtx_lock(&psp->ps_mtx);
549 }
550 
551 /*
552  * System call to cleanup state after a signal
553  * has been taken.  Reset signal mask and
554  * stack state from context left by sendsig (above).
555  * Return to previous pc and psl as specified by
556  * context left by sendsig. Check carefully to
557  * make sure that the user has not modified the
558  * psl to gain improper privileges or to cause
559  * a machine fault.
560  */
561 int
562 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
563 {
564 	struct l_sigframe frame;
565 	struct trapframe *regs;
566 	sigset_t bmask;
567 	l_sigset_t lmask;
568 	int eflags, i;
569 	ksiginfo_t ksi;
570 
571 	regs = td->td_frame;
572 
573 #ifdef DEBUG
574 	if (ldebug(sigreturn))
575 		printf(ARGS(sigreturn, "%p"), (void *)args->sfp);
576 #endif
577 	/*
578 	 * The trampoline code hands us the sigframe.
579 	 * It is unsafe to keep track of it ourselves, in the event that a
580 	 * program jumps out of a signal handler.
581 	 */
582 	if (copyin(args->sfp, &frame, sizeof(frame)) != 0)
583 		return (EFAULT);
584 
585 	/*
586 	 * Check for security violations.
587 	 */
588 #define	EFLAGS_SECURE(ef, oef)	((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
589 	eflags = frame.sf_sc.sc_eflags;
590 	if (!EFLAGS_SECURE(eflags, regs->tf_rflags))
591 		return(EINVAL);
592 
593 	/*
594 	 * Don't allow users to load a valid privileged %cs.  Let the
595 	 * hardware check for invalid selectors, excess privilege in
596 	 * other selectors, invalid %eip's and invalid %esp's.
597 	 */
598 #define	CS_SECURE(cs)	(ISPL(cs) == SEL_UPL)
599 	if (!CS_SECURE(frame.sf_sc.sc_cs)) {
600 		ksiginfo_init_trap(&ksi);
601 		ksi.ksi_signo = SIGBUS;
602 		ksi.ksi_code = BUS_OBJERR;
603 		ksi.ksi_trapno = T_PROTFLT;
604 		ksi.ksi_addr = (void *)regs->tf_rip;
605 		trapsignal(td, &ksi);
606 		return(EINVAL);
607 	}
608 
609 	lmask.__bits[0] = frame.sf_sc.sc_mask;
610 	for (i = 0; i < (LINUX_NSIG_WORDS-1); i++)
611 		lmask.__bits[i+1] = frame.sf_extramask[i];
612 	linux_to_bsd_sigset(&lmask, &bmask);
613 	kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
614 
615 	/*
616 	 * Restore signal context.
617 	 */
618 	regs->tf_rdi    = frame.sf_sc.sc_edi;
619 	regs->tf_rsi    = frame.sf_sc.sc_esi;
620 	regs->tf_rbp    = frame.sf_sc.sc_ebp;
621 	regs->tf_rbx    = frame.sf_sc.sc_ebx;
622 	regs->tf_rdx    = frame.sf_sc.sc_edx;
623 	regs->tf_rcx    = frame.sf_sc.sc_ecx;
624 	regs->tf_rax    = frame.sf_sc.sc_eax;
625 	regs->tf_rip    = frame.sf_sc.sc_eip;
626 	regs->tf_cs     = frame.sf_sc.sc_cs;
627 	regs->tf_ds     = frame.sf_sc.sc_ds;
628 	regs->tf_es     = frame.sf_sc.sc_es;
629 	regs->tf_fs     = frame.sf_sc.sc_fs;
630 	regs->tf_gs     = frame.sf_sc.sc_gs;
631 	regs->tf_rflags = eflags;
632 	regs->tf_rsp    = frame.sf_sc.sc_esp_at_signal;
633 	regs->tf_ss     = frame.sf_sc.sc_ss;
634 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
635 
636 	return (EJUSTRETURN);
637 }
638 
639 /*
640  * System call to cleanup state after a signal
641  * has been taken.  Reset signal mask and
642  * stack state from context left by rt_sendsig (above).
643  * Return to previous pc and psl as specified by
644  * context left by sendsig. Check carefully to
645  * make sure that the user has not modified the
646  * psl to gain improper privileges or to cause
647  * a machine fault.
648  */
649 int
650 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
651 {
652 	struct l_ucontext uc;
653 	struct l_sigcontext *context;
654 	sigset_t bmask;
655 	l_stack_t *lss;
656 	stack_t ss;
657 	struct trapframe *regs;
658 	int eflags;
659 	ksiginfo_t ksi;
660 
661 	regs = td->td_frame;
662 
663 #ifdef DEBUG
664 	if (ldebug(rt_sigreturn))
665 		printf(ARGS(rt_sigreturn, "%p"), (void *)args->ucp);
666 #endif
667 	/*
668 	 * The trampoline code hands us the ucontext.
669 	 * It is unsafe to keep track of it ourselves, in the event that a
670 	 * program jumps out of a signal handler.
671 	 */
672 	if (copyin(args->ucp, &uc, sizeof(uc)) != 0)
673 		return (EFAULT);
674 
675 	context = &uc.uc_mcontext;
676 
677 	/*
678 	 * Check for security violations.
679 	 */
680 #define	EFLAGS_SECURE(ef, oef)	((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
681 	eflags = context->sc_eflags;
682 	if (!EFLAGS_SECURE(eflags, regs->tf_rflags))
683 		return(EINVAL);
684 
685 	/*
686 	 * Don't allow users to load a valid privileged %cs.  Let the
687 	 * hardware check for invalid selectors, excess privilege in
688 	 * other selectors, invalid %eip's and invalid %esp's.
689 	 */
690 #define	CS_SECURE(cs)	(ISPL(cs) == SEL_UPL)
691 	if (!CS_SECURE(context->sc_cs)) {
692 		ksiginfo_init_trap(&ksi);
693 		ksi.ksi_signo = SIGBUS;
694 		ksi.ksi_code = BUS_OBJERR;
695 		ksi.ksi_trapno = T_PROTFLT;
696 		ksi.ksi_addr = (void *)regs->tf_rip;
697 		trapsignal(td, &ksi);
698 		return(EINVAL);
699 	}
700 
701 	linux_to_bsd_sigset(&uc.uc_sigmask, &bmask);
702 	kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
703 
704 	/*
705 	 * Restore signal context
706 	 */
707 	regs->tf_gs	= context->sc_gs;
708 	regs->tf_fs	= context->sc_fs;
709 	regs->tf_es	= context->sc_es;
710 	regs->tf_ds	= context->sc_ds;
711 	regs->tf_rdi    = context->sc_edi;
712 	regs->tf_rsi    = context->sc_esi;
713 	regs->tf_rbp    = context->sc_ebp;
714 	regs->tf_rbx    = context->sc_ebx;
715 	regs->tf_rdx    = context->sc_edx;
716 	regs->tf_rcx    = context->sc_ecx;
717 	regs->tf_rax    = context->sc_eax;
718 	regs->tf_rip    = context->sc_eip;
719 	regs->tf_cs     = context->sc_cs;
720 	regs->tf_rflags = eflags;
721 	regs->tf_rsp    = context->sc_esp_at_signal;
722 	regs->tf_ss     = context->sc_ss;
723 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
724 
725 	/*
726 	 * call sigaltstack & ignore results..
727 	 */
728 	lss = &uc.uc_stack;
729 	ss.ss_sp = PTRIN(lss->ss_sp);
730 	ss.ss_size = lss->ss_size;
731 	ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags);
732 
733 #ifdef DEBUG
734 	if (ldebug(rt_sigreturn))
735 		printf(LMSG("rt_sigret flags: 0x%x, sp: %p, ss: 0x%lx, mask: 0x%x"),
736 		    ss.ss_flags, ss.ss_sp, ss.ss_size, context->sc_mask);
737 #endif
738 	(void)kern_sigaltstack(td, &ss, NULL);
739 
740 	return (EJUSTRETURN);
741 }
742 
743 static int
744 linux32_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
745 {
746 	struct proc *p;
747 	struct trapframe *frame;
748 
749 	p = td->td_proc;
750 	frame = td->td_frame;
751 
752 	sa->args[0] = frame->tf_rbx;
753 	sa->args[1] = frame->tf_rcx;
754 	sa->args[2] = frame->tf_rdx;
755 	sa->args[3] = frame->tf_rsi;
756 	sa->args[4] = frame->tf_rdi;
757 	sa->args[5] = frame->tf_rbp;	/* Unconfirmed */
758 	sa->code = frame->tf_rax;
759 
760 	if (sa->code >= p->p_sysent->sv_size)
761 		sa->callp = &p->p_sysent->sv_table[0];
762 	else
763 		sa->callp = &p->p_sysent->sv_table[sa->code];
764 	sa->narg = sa->callp->sy_narg;
765 
766 	td->td_retval[0] = 0;
767 	td->td_retval[1] = frame->tf_rdx;
768 
769 	return (0);
770 }
771 
772 /*
773  * If a linux binary is exec'ing something, try this image activator
774  * first.  We override standard shell script execution in order to
775  * be able to modify the interpreter path.  We only do this if a linux
776  * binary is doing the exec, so we do not create an EXEC module for it.
777  */
778 static int	exec_linux_imgact_try(struct image_params *iparams);
779 
780 static int
781 exec_linux_imgact_try(struct image_params *imgp)
782 {
783 	const char *head = (const char *)imgp->image_header;
784 	char *rpath;
785 	int error = -1;
786 
787 	/*
788 	* The interpreter for shell scripts run from a linux binary needs
789 	* to be located in /compat/linux if possible in order to recursively
790 	* maintain linux path emulation.
791 	*/
792 	if (((const short *)head)[0] == SHELLMAGIC) {
793 		/*
794 		* Run our normal shell image activator.  If it succeeds attempt
795 		* to use the alternate path for the interpreter.  If an
796 		* alternate * path is found, use our stringspace to store it.
797 		*/
798 		if ((error = exec_shell_imgact(imgp)) == 0) {
799 			linux_emul_convpath(FIRST_THREAD_IN_PROC(imgp->proc),
800 			    imgp->interpreter_name, UIO_SYSSPACE, &rpath, 0,
801 			    AT_FDCWD);
802 			if (rpath != NULL)
803 				imgp->args->fname_buf =
804 				    imgp->interpreter_name = rpath;
805 		}
806 	}
807 	return (error);
808 }
809 
810 /*
811  * Clear registers on exec
812  * XXX copied from ia32_signal.c.
813  */
814 static void
815 exec_linux_setregs(struct thread *td, struct image_params *imgp, u_long stack)
816 {
817 	struct trapframe *regs = td->td_frame;
818 	struct pcb *pcb = td->td_pcb;
819 
820 	mtx_lock(&dt_lock);
821 	if (td->td_proc->p_md.md_ldt != NULL)
822 		user_ldt_free(td);
823 	else
824 		mtx_unlock(&dt_lock);
825 
826 	critical_enter();
827 	wrmsr(MSR_FSBASE, 0);
828 	wrmsr(MSR_KGSBASE, 0);	/* User value while we're in the kernel */
829 	pcb->pcb_fsbase = 0;
830 	pcb->pcb_gsbase = 0;
831 	critical_exit();
832 	pcb->pcb_initial_fpucw = __LINUX_NPXCW__;
833 
834 	bzero((char *)regs, sizeof(struct trapframe));
835 	regs->tf_rip = imgp->entry_addr;
836 	regs->tf_rsp = stack;
837 	regs->tf_rflags = PSL_USER | (regs->tf_rflags & PSL_T);
838 	regs->tf_gs = _ugssel;
839 	regs->tf_fs = _ufssel;
840 	regs->tf_es = _udatasel;
841 	regs->tf_ds = _udatasel;
842 	regs->tf_ss = _udatasel;
843 	regs->tf_flags = TF_HASSEGS;
844 	regs->tf_cs = _ucode32sel;
845 	regs->tf_rbx = imgp->ps_strings;
846 
847 	fpstate_drop(td);
848 
849 	/* Do full restore on return so that we can change to a different %cs */
850 	set_pcb_flags(pcb, PCB_32BIT | PCB_FULL_IRET);
851 	td->td_retval[1] = 0;
852 }
853 
854 /*
855  * XXX copied from ia32_sysvec.c.
856  */
857 static register_t *
858 linux_copyout_strings(struct image_params *imgp)
859 {
860 	int argc, envc;
861 	u_int32_t *vectp;
862 	char *stringp, *destp;
863 	u_int32_t *stack_base;
864 	struct linux32_ps_strings *arginfo;
865 
866 	/*
867 	 * Calculate string base and vector table pointers.
868 	 * Also deal with signal trampoline code for this exec type.
869 	 */
870 	arginfo = (struct linux32_ps_strings *)LINUX32_PS_STRINGS;
871 	destp =	(caddr_t)arginfo - SPARE_USRSPACE - linux_szplatform -
872 	    roundup((ARG_MAX - imgp->args->stringspace),
873 	    sizeof(char *));
874 
875 	/*
876 	 * Install LINUX_PLATFORM
877 	 */
878 	copyout(linux_platform, ((caddr_t)arginfo - linux_szplatform),
879 	    linux_szplatform);
880 
881 	/*
882 	 * If we have a valid auxargs ptr, prepare some room
883 	 * on the stack.
884 	 */
885 	if (imgp->auxargs) {
886 		/*
887 		 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
888 		 * lower compatibility.
889 		 */
890 		imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
891 		    (LINUX_AT_COUNT * 2);
892 		/*
893 		 * The '+ 2' is for the null pointers at the end of each of
894 		 * the arg and env vector sets,and imgp->auxarg_size is room
895 		 * for argument of Runtime loader.
896 		 */
897 		vectp = (u_int32_t *) (destp - (imgp->args->argc +
898 		    imgp->args->envc + 2 + imgp->auxarg_size) *
899 		    sizeof(u_int32_t));
900 
901 	} else
902 		/*
903 		 * The '+ 2' is for the null pointers at the end of each of
904 		 * the arg and env vector sets
905 		 */
906 		vectp = (u_int32_t *)(destp - (imgp->args->argc +
907 		    imgp->args->envc + 2) * sizeof(u_int32_t));
908 
909 	/*
910 	 * vectp also becomes our initial stack base
911 	 */
912 	stack_base = vectp;
913 
914 	stringp = imgp->args->begin_argv;
915 	argc = imgp->args->argc;
916 	envc = imgp->args->envc;
917 	/*
918 	 * Copy out strings - arguments and environment.
919 	 */
920 	copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
921 
922 	/*
923 	 * Fill in "ps_strings" struct for ps, w, etc.
924 	 */
925 	suword32(&arginfo->ps_argvstr, (uint32_t)(intptr_t)vectp);
926 	suword32(&arginfo->ps_nargvstr, argc);
927 
928 	/*
929 	 * Fill in argument portion of vector table.
930 	 */
931 	for (; argc > 0; --argc) {
932 		suword32(vectp++, (uint32_t)(intptr_t)destp);
933 		while (*stringp++ != 0)
934 			destp++;
935 		destp++;
936 	}
937 
938 	/* a null vector table pointer separates the argp's from the envp's */
939 	suword32(vectp++, 0);
940 
941 	suword32(&arginfo->ps_envstr, (uint32_t)(intptr_t)vectp);
942 	suword32(&arginfo->ps_nenvstr, envc);
943 
944 	/*
945 	 * Fill in environment portion of vector table.
946 	 */
947 	for (; envc > 0; --envc) {
948 		suword32(vectp++, (uint32_t)(intptr_t)destp);
949 		while (*stringp++ != 0)
950 			destp++;
951 		destp++;
952 	}
953 
954 	/* end of vector table is a null pointer */
955 	suword32(vectp, 0);
956 
957 	return ((register_t *)stack_base);
958 }
959 
960 static SYSCTL_NODE(_compat, OID_AUTO, linux32, CTLFLAG_RW, 0,
961     "32-bit Linux emulation");
962 
963 static u_long	linux32_maxdsiz = LINUX32_MAXDSIZ;
964 SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxdsiz, CTLFLAG_RW,
965     &linux32_maxdsiz, 0, "");
966 static u_long	linux32_maxssiz = LINUX32_MAXSSIZ;
967 SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxssiz, CTLFLAG_RW,
968     &linux32_maxssiz, 0, "");
969 static u_long	linux32_maxvmem = LINUX32_MAXVMEM;
970 SYSCTL_ULONG(_compat_linux32, OID_AUTO, maxvmem, CTLFLAG_RW,
971     &linux32_maxvmem, 0, "");
972 
973 static void
974 linux32_fixlimit(struct rlimit *rl, int which)
975 {
976 
977 	switch (which) {
978 	case RLIMIT_DATA:
979 		if (linux32_maxdsiz != 0) {
980 			if (rl->rlim_cur > linux32_maxdsiz)
981 				rl->rlim_cur = linux32_maxdsiz;
982 			if (rl->rlim_max > linux32_maxdsiz)
983 				rl->rlim_max = linux32_maxdsiz;
984 		}
985 		break;
986 	case RLIMIT_STACK:
987 		if (linux32_maxssiz != 0) {
988 			if (rl->rlim_cur > linux32_maxssiz)
989 				rl->rlim_cur = linux32_maxssiz;
990 			if (rl->rlim_max > linux32_maxssiz)
991 				rl->rlim_max = linux32_maxssiz;
992 		}
993 		break;
994 	case RLIMIT_VMEM:
995 		if (linux32_maxvmem != 0) {
996 			if (rl->rlim_cur > linux32_maxvmem)
997 				rl->rlim_cur = linux32_maxvmem;
998 			if (rl->rlim_max > linux32_maxvmem)
999 				rl->rlim_max = linux32_maxvmem;
1000 		}
1001 		break;
1002 	}
1003 }
1004 
1005 struct sysentvec elf_linux_sysvec = {
1006 	.sv_size	= LINUX_SYS_MAXSYSCALL,
1007 	.sv_table	= linux_sysent,
1008 	.sv_mask	= 0,
1009 	.sv_sigsize	= LINUX_SIGTBLSZ,
1010 	.sv_sigtbl	= bsd_to_linux_signal,
1011 	.sv_errsize	= ELAST + 1,
1012 	.sv_errtbl	= bsd_to_linux_errno,
1013 	.sv_transtrap	= translate_traps,
1014 	.sv_fixup	= elf_linux_fixup,
1015 	.sv_sendsig	= linux_sendsig,
1016 	.sv_sigcode	= linux_sigcode,
1017 	.sv_szsigcode	= &linux_szsigcode,
1018 	.sv_prepsyscall	= NULL,
1019 	.sv_name	= "Linux ELF32",
1020 	.sv_coredump	= elf32_coredump,
1021 	.sv_imgact_try	= exec_linux_imgact_try,
1022 	.sv_minsigstksz	= LINUX_MINSIGSTKSZ,
1023 	.sv_pagesize	= PAGE_SIZE,
1024 	.sv_minuser	= VM_MIN_ADDRESS,
1025 	.sv_maxuser	= LINUX32_MAXUSER,
1026 	.sv_usrstack	= LINUX32_USRSTACK,
1027 	.sv_psstrings	= LINUX32_PS_STRINGS,
1028 	.sv_stackprot	= VM_PROT_ALL,
1029 	.sv_copyout_strings = linux_copyout_strings,
1030 	.sv_setregs	= exec_linux_setregs,
1031 	.sv_fixlimit	= linux32_fixlimit,
1032 	.sv_maxssiz	= &linux32_maxssiz,
1033 	.sv_flags	= SV_ABI_LINUX | SV_ILP32 | SV_IA32 | SV_SHP,
1034 	.sv_set_syscall_retval = cpu_set_syscall_retval,
1035 	.sv_fetch_syscall_args = linux32_fetch_syscall_args,
1036 	.sv_syscallnames = NULL,
1037 	.sv_shared_page_base = LINUX32_SHAREDPAGE,
1038 	.sv_shared_page_len = PAGE_SIZE,
1039 	.sv_schedtail	= linux_schedtail,
1040 };
1041 INIT_SYSENTVEC(elf_sysvec, &elf_linux_sysvec);
1042 
1043 static char GNU_ABI_VENDOR[] = "GNU";
1044 static int GNULINUX_ABI_DESC = 0;
1045 
1046 static boolean_t
1047 linux32_trans_osrel(const Elf_Note *note, int32_t *osrel)
1048 {
1049 	const Elf32_Word *desc;
1050 	uintptr_t p;
1051 
1052 	p = (uintptr_t)(note + 1);
1053 	p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1054 
1055 	desc = (const Elf32_Word *)p;
1056 	if (desc[0] != GNULINUX_ABI_DESC)
1057 		return (FALSE);
1058 
1059 	/*
1060 	 * For linux we encode osrel as follows (see linux_mib.c):
1061 	 * VVVMMMIII (version, major, minor), see linux_mib.c.
1062 	 */
1063 	*osrel = desc[1] * 1000000 + desc[2] * 1000 + desc[3];
1064 
1065 	return (TRUE);
1066 }
1067 
1068 static Elf_Brandnote linux32_brandnote = {
1069 	.hdr.n_namesz	= sizeof(GNU_ABI_VENDOR),
1070 	.hdr.n_descsz	= 16,	/* XXX at least 16 */
1071 	.hdr.n_type	= 1,
1072 	.vendor		= GNU_ABI_VENDOR,
1073 	.flags		= BN_TRANSLATE_OSREL,
1074 	.trans_osrel	= linux32_trans_osrel
1075 };
1076 
1077 static Elf32_Brandinfo linux_brand = {
1078 	.brand		= ELFOSABI_LINUX,
1079 	.machine	= EM_386,
1080 	.compat_3_brand	= "Linux",
1081 	.emul_path	= "/compat/linux",
1082 	.interp_path	= "/lib/ld-linux.so.1",
1083 	.sysvec		= &elf_linux_sysvec,
1084 	.interp_newpath	= NULL,
1085 	.brand_note	= &linux32_brandnote,
1086 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
1087 };
1088 
1089 static Elf32_Brandinfo linux_glibc2brand = {
1090 	.brand		= ELFOSABI_LINUX,
1091 	.machine	= EM_386,
1092 	.compat_3_brand	= "Linux",
1093 	.emul_path	= "/compat/linux",
1094 	.interp_path	= "/lib/ld-linux.so.2",
1095 	.sysvec		= &elf_linux_sysvec,
1096 	.interp_newpath	= NULL,
1097 	.brand_note	= &linux32_brandnote,
1098 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
1099 };
1100 
1101 Elf32_Brandinfo *linux_brandlist[] = {
1102 	&linux_brand,
1103 	&linux_glibc2brand,
1104 	NULL
1105 };
1106 
1107 static int
1108 linux_elf_modevent(module_t mod, int type, void *data)
1109 {
1110 	Elf32_Brandinfo **brandinfo;
1111 	int error;
1112 	struct linux_ioctl_handler **lihp;
1113 	struct linux_device_handler **ldhp;
1114 
1115 	error = 0;
1116 
1117 	switch(type) {
1118 	case MOD_LOAD:
1119 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1120 		     ++brandinfo)
1121 			if (elf32_insert_brand_entry(*brandinfo) < 0)
1122 				error = EINVAL;
1123 		if (error == 0) {
1124 			SET_FOREACH(lihp, linux_ioctl_handler_set)
1125 				linux_ioctl_register_handler(*lihp);
1126 			SET_FOREACH(ldhp, linux_device_handler_set)
1127 				linux_device_register_handler(*ldhp);
1128 			mtx_init(&emul_lock, "emuldata lock", NULL, MTX_DEF);
1129 			sx_init(&emul_shared_lock, "emuldata->shared lock");
1130 			LIST_INIT(&futex_list);
1131 			mtx_init(&futex_mtx, "ftllk", NULL, MTX_DEF);
1132 			linux_exit_tag = EVENTHANDLER_REGISTER(process_exit,
1133 			    linux_proc_exit, NULL, 1000);
1134 			linux_exec_tag = EVENTHANDLER_REGISTER(process_exec,
1135 			    linux_proc_exec, NULL, 1000);
1136 			linux_szplatform = roundup(strlen(linux_platform) + 1,
1137 			    sizeof(char *));
1138 			linux_osd_jail_register();
1139 			stclohz = (stathz ? stathz : hz);
1140 			if (bootverbose)
1141 				printf("Linux ELF exec handler installed\n");
1142 		} else
1143 			printf("cannot insert Linux ELF brand handler\n");
1144 		break;
1145 	case MOD_UNLOAD:
1146 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1147 		     ++brandinfo)
1148 			if (elf32_brand_inuse(*brandinfo))
1149 				error = EBUSY;
1150 		if (error == 0) {
1151 			for (brandinfo = &linux_brandlist[0];
1152 			     *brandinfo != NULL; ++brandinfo)
1153 				if (elf32_remove_brand_entry(*brandinfo) < 0)
1154 					error = EINVAL;
1155 		}
1156 		if (error == 0) {
1157 			SET_FOREACH(lihp, linux_ioctl_handler_set)
1158 				linux_ioctl_unregister_handler(*lihp);
1159 			SET_FOREACH(ldhp, linux_device_handler_set)
1160 				linux_device_unregister_handler(*ldhp);
1161 			mtx_destroy(&emul_lock);
1162 			sx_destroy(&emul_shared_lock);
1163 			mtx_destroy(&futex_mtx);
1164 			EVENTHANDLER_DEREGISTER(process_exit, linux_exit_tag);
1165 			EVENTHANDLER_DEREGISTER(process_exec, linux_exec_tag);
1166 			linux_osd_jail_deregister();
1167 			if (bootverbose)
1168 				printf("Linux ELF exec handler removed\n");
1169 		} else
1170 			printf("Could not deinstall ELF interpreter entry\n");
1171 		break;
1172 	default:
1173 		return EOPNOTSUPP;
1174 	}
1175 	return error;
1176 }
1177 
1178 static moduledata_t linux_elf_mod = {
1179 	"linuxelf",
1180 	linux_elf_modevent,
1181 	0
1182 };
1183 
1184 DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
1185