xref: /freebsd-13.1/sys/arm64/linux/linux_sysvec.c (revision 95f24ec8)
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.h>
49 #include <vm/pmap.h>
50 #include <vm/vm_param.h>
51 #include <vm/vm_map.h>
52 
53 #include <arm64/linux/linux.h>
54 #include <arm64/linux/linux_proto.h>
55 #include <compat/linux/linux_dtrace.h>
56 #include <compat/linux/linux_emul.h>
57 #include <compat/linux/linux_ioctl.h>
58 #include <compat/linux/linux_mib.h>
59 #include <compat/linux/linux_misc.h>
60 #include <compat/linux/linux_util.h>
61 #include <compat/linux/linux_vdso.h>
62 
63 #include <machine/md_var.h>
64 
65 #ifdef VFP
66 #include <machine/vfp.h>
67 #endif
68 
69 MODULE_VERSION(linux64elf, 1);
70 
71 const char *linux_kplatform;
72 static int linux_szsigcode;
73 static vm_object_t linux_shared_page_obj;
74 static char *linux_shared_page_mapping;
75 extern char _binary_linux_locore_o_start;
76 extern char _binary_linux_locore_o_end;
77 
78 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
79 
80 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
81 
82 static int	linux_copyout_strings(struct image_params *imgp,
83 		    uintptr_t *stack_base);
84 static int	linux_elf_fixup(uintptr_t *stack_base,
85 		    struct image_params *iparams);
86 static bool	linux_trans_osrel(const Elf_Note *note, int32_t *osrel);
87 static void	linux_vdso_install(const void *param);
88 static void	linux_vdso_deinstall(const void *param);
89 static void	linux_set_syscall_retval(struct thread *td, int error);
90 static int	linux_fetch_syscall_args(struct thread *td);
91 static void	linux_exec_setregs(struct thread *td, struct image_params *imgp,
92 		    uintptr_t stack);
93 
94 /* DTrace init */
95 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
96 
97 /* DTrace probes */
98 LIN_SDT_PROBE_DEFINE2(sysvec, linux_translate_traps, todo, "int", "int");
99 LIN_SDT_PROBE_DEFINE0(sysvec, linux_exec_setregs, todo);
100 LIN_SDT_PROBE_DEFINE0(sysvec, linux_copyout_auxargs, todo);
101 LIN_SDT_PROBE_DEFINE0(sysvec, linux_elf_fixup, todo);
102 LIN_SDT_PROBE_DEFINE0(sysvec, linux_rt_sigreturn, todo);
103 LIN_SDT_PROBE_DEFINE0(sysvec, linux_rt_sendsig, todo);
104 LIN_SDT_PROBE_DEFINE0(sysvec, linux_vdso_install, todo);
105 LIN_SDT_PROBE_DEFINE0(sysvec, linux_vdso_deinstall, todo);
106 
107 /* LINUXTODO: do we have traps to translate? */
108 static int
linux_translate_traps(int signal,int trap_code)109 linux_translate_traps(int signal, int trap_code)
110 {
111 
112 	LIN_SDT_PROBE2(sysvec, linux_translate_traps, todo, signal, trap_code);
113 	return (signal);
114 }
115 
116 LINUX_VDSO_SYM_CHAR(linux_platform);
117 
118 static int
linux_fetch_syscall_args(struct thread * td)119 linux_fetch_syscall_args(struct thread *td)
120 {
121 	struct proc *p;
122 	struct syscall_args *sa;
123 	register_t *ap;
124 
125 	p = td->td_proc;
126 	ap = td->td_frame->tf_x;
127 	sa = &td->td_sa;
128 
129 	sa->code = td->td_frame->tf_x[8];
130 	/* LINUXTODO: generic syscall? */
131 	if (sa->code >= p->p_sysent->sv_size)
132 		sa->callp = &p->p_sysent->sv_table[0];
133 	else
134 		sa->callp = &p->p_sysent->sv_table[sa->code];
135 
136 	if (sa->callp->sy_narg > MAXARGS)
137 		panic("ARM64TODO: Could we have more than %d args?", MAXARGS);
138 	memcpy(sa->args, ap, MAXARGS * sizeof(register_t));
139 
140 	td->td_retval[0] = 0;
141 	return (0);
142 }
143 
144 static void
linux_set_syscall_retval(struct thread * td,int error)145 linux_set_syscall_retval(struct thread *td, int error)
146 {
147 
148 	td->td_retval[1] = td->td_frame->tf_x[1];
149 	cpu_set_syscall_retval(td, error);
150 
151 	if (__predict_false(error != 0)) {
152 		if (error != ERESTART && error != EJUSTRETURN)
153 			td->td_frame->tf_x[0] = bsd_to_linux_errno(error);
154 	}
155 }
156 
157 static int
linux_copyout_auxargs(struct image_params * imgp,uintptr_t base)158 linux_copyout_auxargs(struct image_params *imgp, uintptr_t base)
159 {
160 	Elf_Auxargs *args;
161 	Elf_Auxinfo *argarray, *pos;
162 	struct proc *p;
163 	int error, issetugid;
164 
165 	LIN_SDT_PROBE0(sysvec, linux_copyout_auxargs, todo);
166 	p = imgp->proc;
167 
168 	args = (Elf64_Auxargs *)imgp->auxargs;
169 	argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
170 	    M_WAITOK | M_ZERO);
171 
172 	issetugid = p->p_flag & P_SUGID ? 1 : 0;
173 	AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR,
174 	    imgp->proc->p_sysent->sv_shared_page_base);
175 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, *imgp->sysent->sv_hwcap);
176 	AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
177 	AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz);
178 	AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
179 	AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
180 	AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
181 	AUXARGS_ENTRY(pos, AT_BASE, args->base);
182 	AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
183 	AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
184 	AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
185 	AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
186 	AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
187 	AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
188 	AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid);
189 	AUXARGS_ENTRY_PTR(pos, LINUX_AT_RANDOM, imgp->canary);
190 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP2, *imgp->sysent->sv_hwcap2);
191 	if (imgp->execpathp != 0)
192 		AUXARGS_ENTRY_PTR(pos, LINUX_AT_EXECFN, imgp->execpathp);
193 	if (args->execfd != -1)
194 		AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
195 	AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(linux_platform));
196 	AUXARGS_ENTRY(pos, AT_NULL, 0);
197 
198 	free(imgp->auxargs, M_TEMP);
199 	imgp->auxargs = NULL;
200 	KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs"));
201 
202 	error = copyout(argarray, (void *)base,
203 	    sizeof(*argarray) * LINUX_AT_COUNT);
204 	free(argarray, M_TEMP);
205 	return (error);
206 }
207 
208 static int
linux_elf_fixup(uintptr_t * stack_base,struct image_params * imgp)209 linux_elf_fixup(uintptr_t *stack_base, struct image_params *imgp)
210 {
211 
212 	LIN_SDT_PROBE0(sysvec, linux_elf_fixup, todo);
213 
214 	return (0);
215 }
216 
217 /*
218  * Copy strings out to the new process address space, constructing new arg
219  * and env vector tables. Return a pointer to the base so that it can be used
220  * as the initial stack pointer.
221  * LINUXTODO: deduplicate against other linuxulator archs
222  */
223 static int
linux_copyout_strings(struct image_params * imgp,uintptr_t * stack_base)224 linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
225 {
226 	char **vectp;
227 	char *stringp;
228 	uintptr_t destp, ustringp;
229 	struct ps_strings *arginfo;
230 	char canary[LINUX_AT_RANDOM_LEN];
231 	size_t execpath_len;
232 	struct proc *p;
233 	int argc, envc, error;
234 
235 	p = imgp->proc;
236 	arginfo = (struct ps_strings *)PROC_PS_STRINGS(p);
237 	destp = (uintptr_t)arginfo;
238 
239 	if (imgp->execpath != NULL && imgp->auxargs != NULL) {
240 		execpath_len = strlen(imgp->execpath) + 1;
241 		destp -= execpath_len;
242 		destp = rounddown2(destp, sizeof(void *));
243 		imgp->execpathp = (void *)destp;
244 		error = copyout(imgp->execpath, imgp->execpathp, execpath_len);
245 		if (error != 0)
246 			return (error);
247 	}
248 
249 	/* Prepare the canary for SSP. */
250 	arc4rand(canary, sizeof(canary), 0);
251 	destp -= roundup(sizeof(canary), sizeof(void *));
252 	imgp->canary = (void *)destp;
253 	error = copyout(canary, imgp->canary, sizeof(canary));
254 	if (error != 0)
255 		return (error);
256 
257 	/* Allocate room for the argument and environment strings. */
258 	destp -= ARG_MAX - imgp->args->stringspace;
259 	destp = rounddown2(destp, sizeof(void *));
260 	ustringp = destp;
261 
262 	if (imgp->auxargs) {
263 		/*
264 		 * Allocate room on the stack for the ELF auxargs
265 		 * array.  It has up to LINUX_AT_COUNT entries.
266 		 */
267 		destp -= LINUX_AT_COUNT * sizeof(Elf64_Auxinfo);
268 		destp = rounddown2(destp, sizeof(void *));
269 	}
270 
271 	vectp = (char **)destp;
272 
273 	/*
274 	 * Allocate room for argc and the argv[] and env vectors including the
275 	 * terminating NULL pointers.
276 	 */
277 	vectp -= 1 + imgp->args->argc + 1 + imgp->args->envc + 1;
278 	vectp = (char **)STACKALIGN(vectp);
279 
280 	/* vectp also becomes our initial stack base. */
281 	*stack_base = (uintptr_t)vectp;
282 
283 	stringp = imgp->args->begin_argv;
284 	argc = imgp->args->argc;
285 	envc = imgp->args->envc;
286 
287 	/* Copy out strings - arguments and environment. */
288 	error = copyout(stringp, (void *)ustringp,
289 	    ARG_MAX - imgp->args->stringspace);
290 	if (error != 0)
291 		return (error);
292 
293 	/* Fill in "ps_strings" struct for ps, w, etc. */
294 	if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 ||
295 	    suword(&arginfo->ps_nargvstr, argc) != 0)
296 		return (EFAULT);
297 
298 	if (suword(vectp++, argc) != 0)
299 		return (EFAULT);
300 
301 	/* Fill in argument portion of vector table. */
302 	for (; argc > 0; --argc) {
303 		if (suword(vectp++, ustringp) != 0)
304 			return (EFAULT);
305 		while (*stringp++ != 0)
306 			ustringp++;
307 		ustringp++;
308 	}
309 
310 	/* A null vector table pointer separates the argp's from the envp's. */
311 	if (suword(vectp++, 0) != 0)
312 		return (EFAULT);
313 
314 	if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 ||
315 	    suword(&arginfo->ps_nenvstr, envc) != 0)
316 		return (EFAULT);
317 
318 	/* Fill in environment portion of vector table. */
319 	for (; envc > 0; --envc) {
320 		if (suword(vectp++, ustringp) != 0)
321 			return (EFAULT);
322 		while (*stringp++ != 0)
323 			ustringp++;
324 		ustringp++;
325 	}
326 
327 	/* The end of the vector table is a null pointer. */
328 	if (suword(vectp, 0) != 0)
329 		return (EFAULT);
330 
331 	if (imgp->auxargs) {
332 		vectp++;
333 		error = imgp->sysent->sv_copyout_auxargs(imgp,
334 		    (uintptr_t)vectp);
335 		if (error != 0)
336 			return (error);
337 	}
338 
339 	return (0);
340 }
341 
342 /*
343  * Reset registers to default values on exec.
344  */
345 static void
linux_exec_setregs(struct thread * td,struct image_params * imgp,uintptr_t stack)346 linux_exec_setregs(struct thread *td, struct image_params *imgp,
347     uintptr_t stack)
348 {
349 	struct trapframe *regs = td->td_frame;
350 	struct pcb *pcb = td->td_pcb;
351 
352 	/* LINUXTODO: validate */
353 	LIN_SDT_PROBE0(sysvec, linux_exec_setregs, todo);
354 
355 	memset(regs, 0, sizeof(*regs));
356 	/* glibc start.S registers function pointer in x0 with atexit. */
357         regs->tf_sp = stack;
358 #if 0	/* LINUXTODO: See if this is used. */
359 	regs->tf_lr = imgp->entry_addr;
360 #else
361         regs->tf_lr = 0xffffffffffffffff;
362 #endif
363         regs->tf_elr = imgp->entry_addr;
364 
365 	pcb->pcb_tpidr_el0 = 0;
366 	pcb->pcb_tpidrro_el0 = 0;
367 	WRITE_SPECIALREG(tpidrro_el0, 0);
368 	WRITE_SPECIALREG(tpidr_el0, 0);
369 
370 #ifdef VFP
371 	vfp_reset_state(td, pcb);
372 #endif
373 
374 	/*
375 	 * Clear debug register state. It is not applicable to the new process.
376 	 */
377 	bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
378 }
379 
380 int
linux_rt_sigreturn(struct thread * td,struct linux_rt_sigreturn_args * args)381 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
382 {
383 
384 	/* LINUXTODO: implement */
385 	LIN_SDT_PROBE0(sysvec, linux_rt_sigreturn, todo);
386 	return (EDOOFUS);
387 }
388 
389 static void
linux_rt_sendsig(sig_t catcher,ksiginfo_t * ksi,sigset_t * mask)390 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
391 {
392 
393 	/* LINUXTODO: implement */
394 	LIN_SDT_PROBE0(sysvec, linux_rt_sendsig, todo);
395 }
396 
397 struct sysentvec elf_linux_sysvec = {
398 	.sv_size	= LINUX_SYS_MAXSYSCALL,
399 	.sv_table	= linux_sysent,
400 	.sv_transtrap	= linux_translate_traps,
401 	.sv_fixup	= linux_elf_fixup,
402 	.sv_sendsig	= linux_rt_sendsig,
403 	.sv_sigcode	= &_binary_linux_locore_o_start,
404 	.sv_szsigcode	= &linux_szsigcode,
405 	.sv_name	= "Linux ELF64",
406 	.sv_coredump	= elf64_coredump,
407 	.sv_imgact_try	= linux_exec_imgact_try,
408 	.sv_minsigstksz	= LINUX_MINSIGSTKSZ,
409 	.sv_minuser	= VM_MIN_ADDRESS,
410 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
411 	.sv_usrstack	= USRSTACK,
412 	.sv_psstrings	= PS_STRINGS, /* XXX */
413 	.sv_psstringssz	= sizeof(struct ps_strings),
414 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
415 	.sv_copyout_auxargs = linux_copyout_auxargs,
416 	.sv_copyout_strings = linux_copyout_strings,
417 	.sv_setregs	= linux_exec_setregs,
418 	.sv_fixlimit	= NULL,
419 	.sv_maxssiz	= NULL,
420 	.sv_flags	= SV_ABI_LINUX | SV_LP64 | SV_SHP | SV_SIG_DISCIGN |
421 	    SV_SIG_WAITNDQ,
422 	.sv_set_syscall_retval = linux_set_syscall_retval,
423 	.sv_fetch_syscall_args = linux_fetch_syscall_args,
424 	.sv_syscallnames = NULL,
425 	.sv_shared_page_base = SHAREDPAGE,
426 	.sv_shared_page_len = PAGE_SIZE,
427 	.sv_schedtail	= linux_schedtail,
428 	.sv_thread_detach = linux_thread_detach,
429 	.sv_trap	= NULL,
430 	.sv_hwcap	= &elf_hwcap,
431 	.sv_hwcap2	= &elf_hwcap2,
432 	.sv_onexec	= linux_on_exec,
433 	.sv_onexit	= linux_on_exit,
434 	.sv_ontdexit	= linux_thread_dtor,
435 	.sv_setid_allowed = &linux_setid_allowed_query,
436 };
437 
438 static void
linux_vdso_install(const void * param)439 linux_vdso_install(const void *param)
440 {
441 
442 	linux_szsigcode = (&_binary_linux_locore_o_end -
443 	    &_binary_linux_locore_o_start);
444 
445 	if (linux_szsigcode > elf_linux_sysvec.sv_shared_page_len)
446 		panic("invalid Linux VDSO size\n");
447 
448 	__elfN(linux_vdso_fixup)(&elf_linux_sysvec);
449 
450 	linux_shared_page_obj = __elfN(linux_shared_page_init)
451 	    (&linux_shared_page_mapping);
452 
453 	__elfN(linux_vdso_reloc)(&elf_linux_sysvec);
454 
455 	memcpy(linux_shared_page_mapping, elf_linux_sysvec.sv_sigcode,
456 	    linux_szsigcode);
457 	elf_linux_sysvec.sv_shared_page_obj = linux_shared_page_obj;
458 
459 	linux_kplatform = linux_shared_page_mapping +
460 	    (linux_platform - (caddr_t)elf_linux_sysvec.sv_shared_page_base);
461 }
462 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_ANY,
463     linux_vdso_install, NULL);
464 
465 static void
linux_vdso_deinstall(const void * param)466 linux_vdso_deinstall(const void *param)
467 {
468 
469 	LIN_SDT_PROBE0(sysvec, linux_vdso_deinstall, todo);
470 	__elfN(linux_shared_page_fini)(linux_shared_page_obj,
471 	    linux_shared_page_mapping);
472 }
473 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
474     linux_vdso_deinstall, NULL);
475 
476 static char GNU_ABI_VENDOR[] = "GNU";
477 static int GNU_ABI_LINUX = 0;
478 
479 /* LINUXTODO: deduplicate */
480 static bool
linux_trans_osrel(const Elf_Note * note,int32_t * osrel)481 linux_trans_osrel(const Elf_Note *note, int32_t *osrel)
482 {
483 	const Elf32_Word *desc;
484 	uintptr_t p;
485 
486 	p = (uintptr_t)(note + 1);
487 	p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
488 
489 	desc = (const Elf32_Word *)p;
490 	if (desc[0] != GNU_ABI_LINUX)
491 		return (false);
492 
493 	*osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]);
494 	return (true);
495 }
496 
497 static Elf_Brandnote linux64_brandnote = {
498 	.hdr.n_namesz	= sizeof(GNU_ABI_VENDOR),
499 	.hdr.n_descsz	= 16,
500 	.hdr.n_type	= 1,
501 	.vendor		= GNU_ABI_VENDOR,
502 	.flags		= BN_TRANSLATE_OSREL,
503 	.trans_osrel	= linux_trans_osrel
504 };
505 
506 static Elf64_Brandinfo linux_glibc2brand = {
507 	.brand		= ELFOSABI_LINUX,
508 	.machine	= EM_AARCH64,
509 	.compat_3_brand	= "Linux",
510 	.emul_path	= linux_emul_path,
511 	.interp_path	= "/lib64/ld-linux-x86-64.so.2",
512 	.sysvec		= &elf_linux_sysvec,
513 	.interp_newpath	= NULL,
514 	.brand_note	= &linux64_brandnote,
515 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
516 };
517 
518 Elf64_Brandinfo *linux_brandlist[] = {
519 	&linux_glibc2brand,
520 	NULL
521 };
522 
523 static int
linux64_elf_modevent(module_t mod,int type,void * data)524 linux64_elf_modevent(module_t mod, int type, void *data)
525 {
526 	Elf64_Brandinfo **brandinfo;
527 	struct linux_ioctl_handler**lihp;
528 	int error;
529 
530 	error = 0;
531 	switch(type) {
532 	case MOD_LOAD:
533 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
534 		    ++brandinfo)
535 			if (elf64_insert_brand_entry(*brandinfo) < 0)
536 				error = EINVAL;
537 		if (error == 0) {
538 			SET_FOREACH(lihp, linux_ioctl_handler_set)
539 				linux_ioctl_register_handler(*lihp);
540 			stclohz = (stathz ? stathz : hz);
541 			if (bootverbose)
542 				printf("Linux arm64 ELF exec handler installed\n");
543 		}
544 		break;
545 	case MOD_UNLOAD:
546 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
547 		    ++brandinfo)
548 			if (elf64_brand_inuse(*brandinfo))
549 				error = EBUSY;
550 		if (error == 0) {
551 			for (brandinfo = &linux_brandlist[0];
552 			    *brandinfo != NULL; ++brandinfo)
553 				if (elf64_remove_brand_entry(*brandinfo) < 0)
554 					error = EINVAL;
555 		}
556 		if (error == 0) {
557 			SET_FOREACH(lihp, linux_ioctl_handler_set)
558 				linux_ioctl_unregister_handler(*lihp);
559 			if (bootverbose)
560 				printf("Linux ELF exec handler removed\n");
561 		} else
562 			printf("Could not deinstall ELF interpreter entry\n");
563 		break;
564 	default:
565 		return (EOPNOTSUPP);
566 	}
567 	return (error);
568 }
569 
570 static moduledata_t linux64_elf_mod = {
571 	"linux64elf",
572 	linux64_elf_modevent,
573 	0
574 };
575 
576 DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
577 MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1);
578 FEATURE(linux64, "AArch64 Linux 64bit support");
579