xref: /freebsd/sys/arm64/linux/linux_sysvec.c (revision 8c2dd68caa963f1900a8228b0732b04f5d530ffa)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1994-1996 Søren Schmidt
5  * Copyright (c) 2018 Turing Robotic Industries Inc.
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  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/cdefs.h>
35 #include <sys/elf.h>
36 #include <sys/exec.h>
37 #include <sys/imgact.h>
38 #include <sys/imgact_elf.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/module.h>
42 #include <sys/mutex.h>
43 #include <sys/proc.h>
44 #include <sys/signalvar.h>
45 #include <sys/sysctl.h>
46 #include <sys/sysent.h>
47 
48 #include <vm/vm_param.h>
49 
50 #include <arm64/linux/linux.h>
51 #include <arm64/linux/linux_proto.h>
52 #include <compat/linux/linux_dtrace.h>
53 #include <compat/linux/linux_emul.h>
54 #include <compat/linux/linux_ioctl.h>
55 #include <compat/linux/linux_mib.h>
56 #include <compat/linux/linux_misc.h>
57 #include <compat/linux/linux_util.h>
58 #include <compat/linux/linux_vdso.h>
59 
60 #include <machine/md_var.h>
61 
62 #ifdef VFP
63 #include <machine/vfp.h>
64 #endif
65 
66 MODULE_VERSION(linux64elf, 1);
67 
68 static int linux_szsigcode;
69 static vm_object_t linux_shared_page_obj;
70 static char *linux_shared_page_mapping;
71 extern char _binary_linux_locore_o_start;
72 extern char _binary_linux_locore_o_end;
73 
74 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
75 
76 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
77 
78 static int	linux_copyout_strings(struct image_params *imgp,
79 		    uintptr_t *stack_base);
80 static int	linux_elf_fixup(uintptr_t *stack_base,
81 		    struct image_params *iparams);
82 static bool	linux_trans_osrel(const Elf_Note *note, int32_t *osrel);
83 static void	linux_vdso_install(const void *param);
84 static void	linux_vdso_deinstall(const void *param);
85 static void	linux_set_syscall_retval(struct thread *td, int error);
86 static int	linux_fetch_syscall_args(struct thread *td);
87 static void	linux_exec_setregs(struct thread *td, struct image_params *imgp,
88 		    uintptr_t stack);
89 static int	linux_vsyscall(struct thread *td);
90 
91 /* DTrace init */
92 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
93 
94 /* DTrace probes */
95 LIN_SDT_PROBE_DEFINE2(sysvec, linux_translate_traps, todo, "int", "int");
96 LIN_SDT_PROBE_DEFINE0(sysvec, linux_exec_setregs, todo);
97 LIN_SDT_PROBE_DEFINE0(sysvec, linux_copyout_auxargs, todo);
98 LIN_SDT_PROBE_DEFINE0(sysvec, linux_elf_fixup, todo);
99 LIN_SDT_PROBE_DEFINE0(sysvec, linux_rt_sigreturn, todo);
100 LIN_SDT_PROBE_DEFINE0(sysvec, linux_rt_sendsig, todo);
101 LIN_SDT_PROBE_DEFINE0(sysvec, linux_vsyscall, todo);
102 LIN_SDT_PROBE_DEFINE0(sysvec, linux_vdso_install, todo);
103 LIN_SDT_PROBE_DEFINE0(sysvec, linux_vdso_deinstall, todo);
104 
105 /* LINUXTODO: do we have traps to translate? */
106 static int
107 linux_translate_traps(int signal, int trap_code)
108 {
109 
110 	LIN_SDT_PROBE2(sysvec, linux_translate_traps, todo, signal, trap_code);
111 	return (signal);
112 }
113 
114 LINUX_VDSO_SYM_CHAR(linux_platform);
115 
116 static int
117 linux_fetch_syscall_args(struct thread *td)
118 {
119 	struct proc *p;
120 	struct syscall_args *sa;
121 	register_t *ap;
122 
123 	p = td->td_proc;
124 	ap = td->td_frame->tf_x;
125 	sa = &td->td_sa;
126 
127 	sa->code = td->td_frame->tf_x[8];
128 	/* LINUXTODO: generic syscall? */
129 	if (sa->code >= p->p_sysent->sv_size)
130 		sa->callp = &p->p_sysent->sv_table[0];
131 	else
132 		sa->callp = &p->p_sysent->sv_table[sa->code];
133 
134 	if (sa->callp->sy_narg > MAXARGS)
135 		panic("ARM64TODO: Could we have more than %d args?", MAXARGS);
136 	memcpy(sa->args, ap, MAXARGS * sizeof(register_t));
137 
138 	td->td_retval[0] = 0;
139 	return (0);
140 }
141 
142 static void
143 linux_set_syscall_retval(struct thread *td, int error)
144 {
145 
146 	td->td_retval[1] = td->td_frame->tf_x[1];
147 	cpu_set_syscall_retval(td, error);
148 
149 	if (__predict_false(error != 0)) {
150 		if (error != ERESTART && error != EJUSTRETURN)
151 			td->td_frame->tf_x[0] = bsd_to_linux_errno(error);
152 	}
153 }
154 
155 static int
156 linux_copyout_auxargs(struct image_params *imgp, uintptr_t base)
157 {
158 	Elf_Auxargs *args;
159 	Elf_Auxinfo *argarray, *pos;
160 	struct proc *p;
161 	int error, issetugid;
162 
163 	LIN_SDT_PROBE0(sysvec, linux_copyout_auxargs, todo);
164 	p = imgp->proc;
165 
166 	args = (Elf64_Auxargs *)imgp->auxargs;
167 	argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
168 	    M_WAITOK | M_ZERO);
169 
170 	issetugid = p->p_flag & P_SUGID ? 1 : 0;
171 	AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR,
172 	    imgp->proc->p_sysent->sv_shared_page_base);
173 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, *imgp->sysent->sv_hwcap);
174 	AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
175 	AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz);
176 	AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
177 	AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
178 	AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
179 	AUXARGS_ENTRY(pos, AT_BASE, args->base);
180 	AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
181 	AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
182 	AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
183 	AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
184 	AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
185 	AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
186 	AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid);
187 	AUXARGS_ENTRY_PTR(pos, LINUX_AT_RANDOM, imgp->canary);
188 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP2, *imgp->sysent->sv_hwcap2);
189 	if (imgp->execpathp != 0)
190 		AUXARGS_ENTRY_PTR(pos, LINUX_AT_EXECFN, imgp->execpathp);
191 	if (args->execfd != -1)
192 		AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
193 	AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(linux_platform));
194 	AUXARGS_ENTRY(pos, AT_NULL, 0);
195 
196 	free(imgp->auxargs, M_TEMP);
197 	imgp->auxargs = NULL;
198 	KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs"));
199 
200 	error = copyout(argarray, (void *)base,
201 	    sizeof(*argarray) * LINUX_AT_COUNT);
202 	free(argarray, M_TEMP);
203 	return (error);
204 }
205 
206 static int
207 linux_elf_fixup(uintptr_t *stack_base, struct image_params *imgp)
208 {
209 
210 	LIN_SDT_PROBE0(sysvec, linux_elf_fixup, todo);
211 
212 	return (0);
213 }
214 
215 /*
216  * Copy strings out to the new process address space, constructing new arg
217  * and env vector tables. Return a pointer to the base so that it can be used
218  * as the initial stack pointer.
219  * LINUXTODO: deduplicate against other linuxulator archs
220  */
221 static int
222 linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
223 {
224 	char **vectp;
225 	char *stringp;
226 	uintptr_t destp, ustringp;
227 	struct ps_strings *arginfo;
228 	char canary[LINUX_AT_RANDOM_LEN];
229 	size_t execpath_len;
230 	struct proc *p;
231 	int argc, envc, error;
232 
233 	/* Calculate string base and vector table pointers. */
234 	if (imgp->execpath != NULL && imgp->auxargs != NULL)
235 		execpath_len = strlen(imgp->execpath) + 1;
236 	else
237 		execpath_len = 0;
238 
239 	p = imgp->proc;
240 	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
241 	destp = (uintptr_t)arginfo;
242 
243 	if (execpath_len != 0) {
244 		destp -= execpath_len;
245 		destp = rounddown2(destp, sizeof(void *));
246 		imgp->execpathp = (void *)destp;
247 		error = copyout(imgp->execpath, imgp->execpathp, execpath_len);
248 		if (error != 0)
249 			return (error);
250 	}
251 
252 	/* Prepare the canary for SSP. */
253 	arc4rand(canary, sizeof(canary), 0);
254 	destp -= roundup(sizeof(canary), sizeof(void *));
255 	imgp->canary = (void *)destp;
256 	error = copyout(canary, imgp->canary, sizeof(canary));
257 	if (error != 0)
258 		return (error);
259 
260 	/* Allocate room for the argument and environment strings. */
261 	destp -= ARG_MAX - imgp->args->stringspace;
262 	destp = rounddown2(destp, sizeof(void *));
263 	ustringp = destp;
264 
265 	if (imgp->auxargs) {
266 		/*
267 		 * Allocate room on the stack for the ELF auxargs
268 		 * array.  It has up to LINUX_AT_COUNT entries.
269 		 */
270 		destp -= LINUX_AT_COUNT * sizeof(Elf64_Auxinfo);
271 		destp = rounddown2(destp, sizeof(void *));
272 	}
273 
274 	vectp = (char **)destp;
275 
276 	/*
277 	 * Allocate room for argc and the argv[] and env vectors including the
278 	 * terminating NULL pointers.
279 	 */
280 	vectp -= 1 + imgp->args->argc + 1 + imgp->args->envc + 1;
281 	vectp = (char **)STACKALIGN(vectp);
282 
283 	/* vectp also becomes our initial stack base. */
284 	*stack_base = (uintptr_t)vectp;
285 
286 	stringp = imgp->args->begin_argv;
287 	argc = imgp->args->argc;
288 	envc = imgp->args->envc;
289 
290 	/* Copy out strings - arguments and environment. */
291 	error = copyout(stringp, (void *)ustringp,
292 	    ARG_MAX - imgp->args->stringspace);
293 	if (error != 0)
294 		return (error);
295 
296 	/* Fill in "ps_strings" struct for ps, w, etc. */
297 	if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 ||
298 	    suword(&arginfo->ps_nargvstr, argc) != 0)
299 		return (EFAULT);
300 
301 	if (suword(vectp++, argc) != 0)
302 		return (EFAULT);
303 
304 	/* Fill in argument portion of vector table. */
305 	for (; argc > 0; --argc) {
306 		if (suword(vectp++, ustringp) != 0)
307 			return (EFAULT);
308 		while (*stringp++ != 0)
309 			ustringp++;
310 		ustringp++;
311 	}
312 
313 	/* A null vector table pointer separates the argp's from the envp's. */
314 	if (suword(vectp++, 0) != 0)
315 		return (EFAULT);
316 
317 	if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 ||
318 	    suword(&arginfo->ps_nenvstr, envc) != 0)
319 		return (EFAULT);
320 
321 	/* Fill in environment portion of vector table. */
322 	for (; envc > 0; --envc) {
323 		if (suword(vectp++, ustringp) != 0)
324 			return (EFAULT);
325 		while (*stringp++ != 0)
326 			ustringp++;
327 		ustringp++;
328 	}
329 
330 	/* The end of the vector table is a null pointer. */
331 	if (suword(vectp, 0) != 0)
332 		return (EFAULT);
333 
334 	if (imgp->auxargs) {
335 		vectp++;
336 		error = imgp->sysent->sv_copyout_auxargs(imgp,
337 		    (uintptr_t)vectp);
338 		if (error != 0)
339 			return (error);
340 	}
341 
342 	return (0);
343 }
344 
345 /*
346  * Reset registers to default values on exec.
347  */
348 static void
349 linux_exec_setregs(struct thread *td, struct image_params *imgp,
350     uintptr_t stack)
351 {
352 	struct trapframe *regs = td->td_frame;
353 	struct pcb *pcb = td->td_pcb;
354 
355 	/* LINUXTODO: validate */
356 	LIN_SDT_PROBE0(sysvec, linux_exec_setregs, todo);
357 
358 	memset(regs, 0, sizeof(*regs));
359 	/* glibc start.S registers function pointer in x0 with atexit. */
360         regs->tf_sp = stack;
361 #if 0	/* LINUXTODO: See if this is used. */
362 	regs->tf_lr = imgp->entry_addr;
363 #else
364         regs->tf_lr = 0xffffffffffffffff;
365 #endif
366         regs->tf_elr = imgp->entry_addr;
367 
368 	pcb->pcb_tpidr_el0 = 0;
369 	pcb->pcb_tpidrro_el0 = 0;
370 	WRITE_SPECIALREG(tpidrro_el0, 0);
371 	WRITE_SPECIALREG(tpidr_el0, 0);
372 
373 #ifdef VFP
374 	vfp_reset_state(td, pcb);
375 #endif
376 
377 	/*
378 	 * Clear debug register state. It is not applicable to the new process.
379 	 */
380 	bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
381 }
382 
383 int
384 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
385 {
386 
387 	/* LINUXTODO: implement */
388 	LIN_SDT_PROBE0(sysvec, linux_rt_sigreturn, todo);
389 	return (EDOOFUS);
390 }
391 
392 static void
393 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
394 {
395 
396 	/* LINUXTODO: implement */
397 	LIN_SDT_PROBE0(sysvec, linux_rt_sendsig, todo);
398 }
399 
400 static int
401 linux_vsyscall(struct thread *td)
402 {
403 
404 	/* LINUXTODO: implement */
405 	LIN_SDT_PROBE0(sysvec, linux_vsyscall, todo);
406 	return (EDOOFUS);
407 }
408 
409 struct sysentvec elf_linux_sysvec = {
410 	.sv_size	= LINUX_SYS_MAXSYSCALL,
411 	.sv_table	= linux_sysent,
412 	.sv_transtrap	= linux_translate_traps,
413 	.sv_fixup	= linux_elf_fixup,
414 	.sv_sendsig	= linux_rt_sendsig,
415 	.sv_sigcode	= &_binary_linux_locore_o_start,
416 	.sv_szsigcode	= &linux_szsigcode,
417 	.sv_name	= "Linux ELF64",
418 	.sv_coredump	= elf64_coredump,
419 	.sv_elf_core_osabi = ELFOSABI_NONE,
420 	.sv_elf_core_abi_vendor = FREEBSD_ABI_VENDOR,
421 	.sv_elf_core_prepare_notes = elf64_prepare_notes,
422 	.sv_imgact_try	= linux_exec_imgact_try,
423 	.sv_minsigstksz	= LINUX_MINSIGSTKSZ,
424 	.sv_minuser	= VM_MIN_ADDRESS,
425 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
426 	.sv_usrstack	= USRSTACK,
427 	.sv_psstrings	= PS_STRINGS, /* XXX */
428 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
429 	.sv_copyout_auxargs = linux_copyout_auxargs,
430 	.sv_copyout_strings = linux_copyout_strings,
431 	.sv_setregs	= linux_exec_setregs,
432 	.sv_fixlimit	= NULL,
433 	.sv_maxssiz	= NULL,
434 	.sv_flags	= SV_ABI_LINUX | SV_LP64 | SV_SHP | SV_SIG_DISCIGN |
435 	    SV_SIG_WAITNDQ,
436 	.sv_set_syscall_retval = linux_set_syscall_retval,
437 	.sv_fetch_syscall_args = linux_fetch_syscall_args,
438 	.sv_syscallnames = NULL,
439 	.sv_shared_page_base = SHAREDPAGE,
440 	.sv_shared_page_len = PAGE_SIZE,
441 	.sv_schedtail	= linux_schedtail,
442 	.sv_thread_detach = linux_thread_detach,
443 	.sv_trap	= linux_vsyscall,
444 	.sv_hwcap	= &elf_hwcap,
445 	.sv_hwcap2	= &elf_hwcap2,
446 	.sv_onexec	= linux_on_exec,
447 	.sv_onexit	= linux_on_exit,
448 	.sv_ontdexit	= linux_thread_dtor,
449 	.sv_setid_allowed = &linux_setid_allowed_query,
450 };
451 
452 static void
453 linux_vdso_install(const void *param)
454 {
455 
456 	linux_szsigcode = (&_binary_linux_locore_o_end -
457 	    &_binary_linux_locore_o_start);
458 
459 	if (linux_szsigcode > elf_linux_sysvec.sv_shared_page_len)
460 		panic("invalid Linux VDSO size\n");
461 
462 	__elfN(linux_vdso_fixup)(&elf_linux_sysvec);
463 
464 	linux_shared_page_obj = __elfN(linux_shared_page_init)
465 	    (&linux_shared_page_mapping);
466 
467 	__elfN(linux_vdso_reloc)(&elf_linux_sysvec);
468 
469 	memcpy(linux_shared_page_mapping, elf_linux_sysvec.sv_sigcode,
470 	    linux_szsigcode);
471 	elf_linux_sysvec.sv_shared_page_obj = linux_shared_page_obj;
472 }
473 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_ANY,
474     linux_vdso_install, NULL);
475 
476 static void
477 linux_vdso_deinstall(const void *param)
478 {
479 
480 	LIN_SDT_PROBE0(sysvec, linux_vdso_deinstall, todo);
481 	__elfN(linux_shared_page_fini)(linux_shared_page_obj,
482 	    linux_shared_page_mapping);
483 }
484 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
485     linux_vdso_deinstall, NULL);
486 
487 static char GNU_ABI_VENDOR[] = "GNU";
488 static int GNU_ABI_LINUX = 0;
489 
490 /* LINUXTODO: deduplicate */
491 static bool
492 linux_trans_osrel(const Elf_Note *note, int32_t *osrel)
493 {
494 	const Elf32_Word *desc;
495 	uintptr_t p;
496 
497 	p = (uintptr_t)(note + 1);
498 	p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
499 
500 	desc = (const Elf32_Word *)p;
501 	if (desc[0] != GNU_ABI_LINUX)
502 		return (false);
503 
504 	*osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]);
505 	return (true);
506 }
507 
508 static Elf_Brandnote linux64_brandnote = {
509 	.hdr.n_namesz	= sizeof(GNU_ABI_VENDOR),
510 	.hdr.n_descsz	= 16,
511 	.hdr.n_type	= 1,
512 	.vendor		= GNU_ABI_VENDOR,
513 	.flags		= BN_TRANSLATE_OSREL,
514 	.trans_osrel	= linux_trans_osrel
515 };
516 
517 static Elf64_Brandinfo linux_glibc2brand = {
518 	.brand		= ELFOSABI_LINUX,
519 	.machine	= EM_AARCH64,
520 	.compat_3_brand	= "Linux",
521 	.emul_path	= linux_emul_path,
522 	.interp_path	= "/lib64/ld-linux-x86-64.so.2",
523 	.sysvec		= &elf_linux_sysvec,
524 	.interp_newpath	= NULL,
525 	.brand_note	= &linux64_brandnote,
526 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
527 };
528 
529 Elf64_Brandinfo *linux_brandlist[] = {
530 	&linux_glibc2brand,
531 	NULL
532 };
533 
534 static int
535 linux64_elf_modevent(module_t mod, int type, void *data)
536 {
537 	Elf64_Brandinfo **brandinfo;
538 	struct linux_ioctl_handler**lihp;
539 	int error;
540 
541 	error = 0;
542 	switch(type) {
543 	case MOD_LOAD:
544 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
545 		    ++brandinfo)
546 			if (elf64_insert_brand_entry(*brandinfo) < 0)
547 				error = EINVAL;
548 		if (error == 0) {
549 			SET_FOREACH(lihp, linux_ioctl_handler_set)
550 				linux_ioctl_register_handler(*lihp);
551 			stclohz = (stathz ? stathz : hz);
552 			if (bootverbose)
553 				printf("Linux arm64 ELF exec handler installed\n");
554 		}
555 		break;
556 	case MOD_UNLOAD:
557 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
558 		    ++brandinfo)
559 			if (elf64_brand_inuse(*brandinfo))
560 				error = EBUSY;
561 		if (error == 0) {
562 			for (brandinfo = &linux_brandlist[0];
563 			    *brandinfo != NULL; ++brandinfo)
564 				if (elf64_remove_brand_entry(*brandinfo) < 0)
565 					error = EINVAL;
566 		}
567 		if (error == 0) {
568 			SET_FOREACH(lihp, linux_ioctl_handler_set)
569 				linux_ioctl_unregister_handler(*lihp);
570 			if (bootverbose)
571 				printf("Linux ELF exec handler removed\n");
572 		} else
573 			printf("Could not deinstall ELF interpreter entry\n");
574 		break;
575 	default:
576 		return (EOPNOTSUPP);
577 	}
578 	return (error);
579 }
580 
581 static moduledata_t linux64_elf_mod = {
582 	"linux64elf",
583 	linux64_elf_modevent,
584 	0
585 };
586 
587 DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
588 MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1);
589 FEATURE(linux64, "AArch64 Linux 64bit support");
590