xref: /freebsd/sys/arm64/linux/linux_sysvec.c (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #define	__ELF_WORD_SIZE	64
31 
32 #include <sys/param.h>
33 #include <sys/elf.h>
34 #include <sys/exec.h>
35 #include <sys/imgact.h>
36 #include <sys/imgact_elf.h>
37 #include <sys/kernel.h>
38 #include <sys/ktr.h>
39 #include <sys/lock.h>
40 #include <sys/module.h>
41 #include <sys/mutex.h>
42 #include <sys/proc.h>
43 #include <sys/stddef.h>
44 #include <sys/syscallsubr.h>
45 #include <sys/sysctl.h>
46 #include <sys/sysent.h>
47 
48 #include <vm/pmap.h>
49 #include <vm/vm.h>
50 #include <vm/vm_map.h>
51 #include <vm/vm_page.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_elf.h>
57 #include <compat/linux/linux_emul.h>
58 #include <compat/linux/linux_fork.h>
59 #include <compat/linux/linux_ioctl.h>
60 #include <compat/linux/linux_mib.h>
61 #include <compat/linux/linux_misc.h>
62 #include <compat/linux/linux_signal.h>
63 #include <compat/linux/linux_util.h>
64 #include <compat/linux/linux_vdso.h>
65 
66 #include <arm64/linux/linux_sigframe.h>
67 
68 #include <machine/md_var.h>
69 #include <machine/pcb.h>
70 #ifdef VFP
71 #include <machine/vfp.h>
72 #endif
73 
74 MODULE_VERSION(linux64elf, 1);
75 
76 #define	LINUX_VDSOPAGE_SIZE	PAGE_SIZE * 2
77 #define	LINUX_VDSOPAGE		(VM_MAXUSER_ADDRESS - \
78 				    LINUX_VDSOPAGE_SIZE)
79 #define	LINUX_SHAREDPAGE	(LINUX_VDSOPAGE - PAGE_SIZE)
80 				/*
81 				 * PAGE_SIZE - the size
82 				 * of the native SHAREDPAGE
83 				 */
84 #define	LINUX_USRSTACK		LINUX_SHAREDPAGE
85 #define	LINUX_PS_STRINGS	(LINUX_USRSTACK - \
86 				    sizeof(struct ps_strings))
87 
88 static int linux_szsigcode;
89 static vm_object_t linux_vdso_obj;
90 static char *linux_vdso_mapping;
91 extern char _binary_linux_vdso_so_o_start;
92 extern char _binary_linux_vdso_so_o_end;
93 static vm_offset_t linux_vdso_base;
94 
95 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
96 extern const char *linux_syscallnames[];
97 
98 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
99 
100 static void	linux_vdso_install(const void *param);
101 static void	linux_vdso_deinstall(const void *param);
102 static void	linux_vdso_reloc(char *mapping, Elf_Addr offset);
103 static void	linux_set_syscall_retval(struct thread *td, int error);
104 static int	linux_fetch_syscall_args(struct thread *td);
105 static void	linux_exec_setregs(struct thread *td, struct image_params *imgp,
106 		    uintptr_t stack);
107 static void	linux_exec_sysvec_init(void *param);
108 static int	linux_on_exec_vmspace(struct proc *p,
109 		    struct image_params *imgp);
110 
111 /* DTrace init */
112 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
113 
114 /* DTrace probes */
115 LIN_SDT_PROBE_DEFINE0(sysvec, linux_exec_setregs, todo);
116 
117 LINUX_VDSO_SYM_CHAR(linux_platform);
118 LINUX_VDSO_SYM_INTPTR(kern_timekeep_base);
119 LINUX_VDSO_SYM_INTPTR(__user_rt_sigreturn);
120 
121 static int
122 linux_fetch_syscall_args(struct thread *td)
123 {
124 	struct proc *p;
125 	struct syscall_args *sa;
126 	register_t *ap;
127 
128 	p = td->td_proc;
129 	ap = td->td_frame->tf_x;
130 	sa = &td->td_sa;
131 
132 	sa->code = td->td_frame->tf_x[8];
133 	sa->original_code = sa->code;
134 	/* LINUXTODO: generic syscall? */
135 	if (sa->code >= p->p_sysent->sv_size)
136 		sa->callp = &p->p_sysent->sv_table[0];
137 	else
138 		sa->callp = &p->p_sysent->sv_table[sa->code];
139 
140 	if (sa->callp->sy_narg > nitems(sa->args))
141 		panic("ARM64TODO: Could we have more than %zu args?",
142 		    nitems(sa->args));
143 	memcpy(sa->args, ap, nitems(sa->args) * sizeof(register_t));
144 
145 	td->td_retval[0] = 0;
146 	return (0);
147 }
148 
149 static void
150 linux_set_syscall_retval(struct thread *td, int error)
151 {
152 
153 	td->td_retval[1] = td->td_frame->tf_x[1];
154 	cpu_set_syscall_retval(td, error);
155 
156 	if (__predict_false(error != 0)) {
157 		if (error != ERESTART && error != EJUSTRETURN)
158 			td->td_frame->tf_x[0] = bsd_to_linux_errno(error);
159 	}
160 }
161 
162 void
163 linux64_arch_copyout_auxargs(struct image_params *imgp, Elf_Auxinfo **pos)
164 {
165 
166 	AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
167 	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, *imgp->sysent->sv_hwcap);
168 	AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, *imgp->sysent->sv_hwcap2);
169 	AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform));
170 }
171 
172 /*
173  * Reset registers to default values on exec.
174  */
175 static void
176 linux_exec_setregs(struct thread *td, struct image_params *imgp,
177     uintptr_t stack)
178 {
179 	struct trapframe *regs = td->td_frame;
180 	struct pcb *pcb = td->td_pcb;
181 
182 	/* LINUXTODO: validate */
183 	LIN_SDT_PROBE0(sysvec, linux_exec_setregs, todo);
184 
185 	memset(regs, 0, sizeof(*regs));
186 	/* glibc start.S registers function pointer in x0 with atexit. */
187         regs->tf_sp = stack;
188 #if 0	/* LINUXTODO: See if this is used. */
189 	regs->tf_lr = imgp->entry_addr;
190 #else
191         regs->tf_lr = 0xffffffffffffffff;
192 #endif
193         regs->tf_elr = imgp->entry_addr;
194 
195 	pcb->pcb_tpidr_el0 = 0;
196 	pcb->pcb_tpidrro_el0 = 0;
197 	WRITE_SPECIALREG(tpidrro_el0, 0);
198 	WRITE_SPECIALREG(tpidr_el0, 0);
199 
200 #ifdef VFP
201 	vfp_reset_state(td, pcb);
202 #endif
203 
204 	/*
205 	 * Clear debug register state. It is not applicable to the new process.
206 	 */
207 	bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
208 }
209 
210 int
211 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
212 {
213 	struct l_sigframe *frame;
214 	ucontext_t uc;
215 	struct trapframe *tf;
216 	int error;
217 
218 	tf = td->td_frame;
219 	frame = (struct l_sigframe *)tf->tf_sp;
220 
221 	if (copyin((void *)&frame->uc, &uc, sizeof(uc)))
222 		return (EFAULT);
223 
224 	error = set_mcontext(td, &uc.uc_mcontext);
225 	if (error != 0)
226 		return (error);
227 
228 	/* Restore signal mask. */
229 	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
230 
231 	return (EJUSTRETURN);
232 }
233 
234 static void
235 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
236 {
237 	struct thread *td;
238 	struct proc *p;
239 	struct trapframe *tf;
240 	struct l_sigframe *fp, *frame;
241 	struct l_fpsimd_context *fpsimd;
242 	struct l_esr_context *esr;
243 	l_stack_t uc_stack;
244 	ucontext_t uc;
245 	uint8_t *scr;
246 	struct sigacts *psp;
247 	int onstack, sig, issiginfo;
248 
249 	td = curthread;
250 	p = td->td_proc;
251 	PROC_LOCK_ASSERT(p, MA_OWNED);
252 
253 	sig = ksi->ksi_signo;
254 	psp = p->p_sigacts;
255 	mtx_assert(&psp->ps_mtx, MA_OWNED);
256 
257 	tf = td->td_frame;
258 	onstack = sigonstack(tf->tf_sp);
259 	issiginfo = SIGISMEMBER(psp->ps_siginfo, sig);
260 
261 	CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
262 	    catcher, sig);
263 
264 	/* Allocate and validate space for the signal handler context. */
265 	if ((td->td_pflags & TDP_ALTSTACK) != 0 && !onstack &&
266 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
267 		fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
268 		    td->td_sigstk.ss_size);
269 #if defined(COMPAT_43)
270 		td->td_sigstk.ss_flags |= SS_ONSTACK;
271 #endif
272 	} else {
273 		fp = (struct l_sigframe *)td->td_frame->tf_sp;
274 	}
275 
276 	/* Make room, keeping the stack aligned */
277 	fp--;
278 	fp = (struct l_sigframe *)STACKALIGN(fp);
279 
280 	get_mcontext(td, &uc.uc_mcontext, 0);
281 	uc.uc_sigmask = *mask;
282 
283 	uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
284 	uc_stack.ss_size = td->td_sigstk.ss_size;
285 	uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) != 0 ?
286 	    (onstack ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
287 	mtx_unlock(&psp->ps_mtx);
288 	PROC_UNLOCK(td->td_proc);
289 
290 	/* Fill in the frame to copy out */
291 	frame = malloc(sizeof(*frame), M_LINUX, M_WAITOK | M_ZERO);
292 
293 	memcpy(&frame->sf.sf_uc.uc_sc.regs, tf->tf_x, sizeof(tf->tf_x));
294 	frame->sf.sf_uc.uc_sc.regs[30] = tf->tf_lr;
295 	frame->sf.sf_uc.uc_sc.sp = tf->tf_sp;
296 	frame->sf.sf_uc.uc_sc.pc = tf->tf_elr;
297 	frame->sf.sf_uc.uc_sc.pstate = tf->tf_spsr;
298 	frame->sf.sf_uc.uc_sc.fault_address = (register_t)ksi->ksi_addr;
299 
300 	/* Stack frame for unwinding */
301 	frame->fp = tf->tf_x[29];
302 	frame->lr = tf->tf_elr;
303 
304 	/* Translate the signal. */
305 	sig = bsd_to_linux_signal(sig);
306 	siginfo_to_lsiginfo(&ksi->ksi_info, &frame->sf.sf_si, sig);
307 	bsd_to_linux_sigset(mask, &frame->sf.sf_uc.uc_sigmask);
308 
309 	/*
310 	 * Prepare fpsimd & esr. Does not check sizes, as
311 	 * __reserved is big enougth.
312 	 */
313 	scr = (uint8_t *)&frame->sf.sf_uc.uc_sc.__reserved;
314 #ifdef VFP
315 	fpsimd = (struct l_fpsimd_context *) scr;
316 	fpsimd->head.magic = L_FPSIMD_MAGIC;
317 	fpsimd->head.size = sizeof(struct l_fpsimd_context);
318 	fpsimd->fpsr = uc.uc_mcontext.mc_fpregs.fp_sr;
319 	fpsimd->fpcr = uc.uc_mcontext.mc_fpregs.fp_cr;
320 
321 	memcpy(fpsimd->vregs, &uc.uc_mcontext.mc_fpregs.fp_q,
322 	    sizeof(uc.uc_mcontext.mc_fpregs.fp_q));
323 	scr += roundup(sizeof(struct l_fpsimd_context), 16);
324 #endif
325 	if (ksi->ksi_addr != 0) {
326 		esr = (struct l_esr_context *) scr;
327 		esr->head.magic = L_ESR_MAGIC;
328 		esr->head.size = sizeof(struct l_esr_context);
329 		esr->esr = tf->tf_esr;
330 	}
331 
332 	memcpy(&frame->sf.sf_uc.uc_stack, &uc_stack, sizeof(uc_stack));
333 	memcpy(&frame->uc, &uc, sizeof(uc));
334 
335 	/* Copy the sigframe out to the user's stack. */
336 	if (copyout(frame, fp, sizeof(*fp)) != 0) {
337 		/* Process has trashed its stack. Kill it. */
338 		free(frame, M_LINUX);
339 		CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
340 		PROC_LOCK(p);
341 		sigexit(td, SIGILL);
342 	}
343 	free(frame, M_LINUX);
344 
345 	tf->tf_x[0]= sig;
346 	if (issiginfo) {
347 		tf->tf_x[1] = (register_t)&fp->sf.sf_si;
348 		tf->tf_x[2] = (register_t)&fp->sf.sf_uc;
349 	} else {
350 		tf->tf_x[1] = 0;
351 		tf->tf_x[2] = 0;
352 	}
353 	tf->tf_x[29] = (register_t)&fp->fp;
354 	tf->tf_elr = (register_t)catcher;
355 	tf->tf_sp = (register_t)fp;
356 	tf->tf_lr = (register_t)__user_rt_sigreturn;
357 
358 	CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_elr,
359 	    tf->tf_sp);
360 
361 	PROC_LOCK(p);
362 	mtx_lock(&psp->ps_mtx);
363 }
364 
365 struct sysentvec elf_linux_sysvec = {
366 	.sv_size	= LINUX_SYS_MAXSYSCALL,
367 	.sv_table	= linux_sysent,
368 	.sv_fixup	= __elfN(freebsd_fixup),
369 	.sv_sendsig	= linux_rt_sendsig,
370 	.sv_sigcode	= &_binary_linux_vdso_so_o_start,
371 	.sv_szsigcode	= &linux_szsigcode,
372 	.sv_name	= "Linux ELF64",
373 	.sv_coredump	= elf64_coredump,
374 	.sv_elf_core_osabi = ELFOSABI_NONE,
375 	.sv_elf_core_abi_vendor = LINUX_ABI_VENDOR,
376 	.sv_elf_core_prepare_notes = linux64_prepare_notes,
377 	.sv_minsigstksz	= LINUX_MINSIGSTKSZ,
378 	.sv_minuser	= VM_MIN_ADDRESS,
379 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
380 	.sv_usrstack	= LINUX_USRSTACK,
381 	.sv_psstrings	= LINUX_PS_STRINGS,
382 	.sv_psstringssz	= sizeof(struct ps_strings),
383 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
384 	.sv_copyout_auxargs = __linuxN(copyout_auxargs),
385 	.sv_copyout_strings = __linuxN(copyout_strings),
386 	.sv_setregs	= linux_exec_setregs,
387 	.sv_fixlimit	= NULL,
388 	.sv_maxssiz	= NULL,
389 	.sv_flags	= SV_ABI_LINUX | SV_LP64 | SV_SHP | SV_SIG_DISCIGN |
390 	    SV_SIG_WAITNDQ | SV_TIMEKEEP,
391 	.sv_set_syscall_retval = linux_set_syscall_retval,
392 	.sv_fetch_syscall_args = linux_fetch_syscall_args,
393 	.sv_syscallnames = linux_syscallnames,
394 	.sv_shared_page_base = LINUX_SHAREDPAGE,
395 	.sv_shared_page_len = PAGE_SIZE,
396 	.sv_schedtail	= linux_schedtail,
397 	.sv_thread_detach = linux_thread_detach,
398 	.sv_trap	= NULL,
399 	.sv_hwcap	= &elf_hwcap,
400 	.sv_hwcap2	= &elf_hwcap2,
401 	.sv_onexec	= linux_on_exec_vmspace,
402 	.sv_onexit	= linux_on_exit,
403 	.sv_ontdexit	= linux_thread_dtor,
404 	.sv_setid_allowed = &linux_setid_allowed_query,
405 };
406 
407 static int
408 linux_on_exec_vmspace(struct proc *p, struct image_params *imgp)
409 {
410 	int error;
411 
412 	error = linux_map_vdso(p, linux_vdso_obj, linux_vdso_base,
413 	    LINUX_VDSOPAGE_SIZE, imgp);
414 	if (error == 0)
415 		error = linux_on_exec(p, imgp);
416 	return (error);
417 }
418 
419 /*
420  * linux_vdso_install() and linux_exec_sysvec_init() must be called
421  * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
422  */
423 static void
424 linux_exec_sysvec_init(void *param)
425 {
426 	l_uintptr_t *ktimekeep_base;
427 	struct sysentvec *sv;
428 	ptrdiff_t tkoff;
429 
430 	sv = param;
431 	/* Fill timekeep_base */
432 	exec_sysvec_init(sv);
433 
434 	tkoff = kern_timekeep_base - linux_vdso_base;
435 	ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
436 	*ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
437 }
438 SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
439     linux_exec_sysvec_init, &elf_linux_sysvec);
440 
441 static void
442 linux_vdso_install(const void *param)
443 {
444 	char *vdso_start = &_binary_linux_vdso_so_o_start;
445 	char *vdso_end = &_binary_linux_vdso_so_o_end;
446 
447 	linux_szsigcode = vdso_end - vdso_start;
448 	MPASS(linux_szsigcode <= LINUX_VDSOPAGE_SIZE);
449 
450 	linux_vdso_base = LINUX_VDSOPAGE;
451 
452 	__elfN(linux_vdso_fixup)(vdso_start, linux_vdso_base);
453 
454 	linux_vdso_obj = __elfN(linux_shared_page_init)
455 	    (&linux_vdso_mapping, LINUX_VDSOPAGE_SIZE);
456 	bcopy(vdso_start, linux_vdso_mapping, linux_szsigcode);
457 
458 	linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
459 }
460 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
461     linux_vdso_install, NULL);
462 
463 static void
464 linux_vdso_deinstall(const void *param)
465 {
466 
467 	__elfN(linux_shared_page_fini)(linux_vdso_obj,
468 	    linux_vdso_mapping, LINUX_VDSOPAGE_SIZE);
469 }
470 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
471     linux_vdso_deinstall, NULL);
472 
473 static void
474 linux_vdso_reloc(char *mapping, Elf_Addr offset)
475 {
476 	Elf_Size rtype, symidx;
477 	const Elf_Rela *rela;
478 	const Elf_Shdr *shdr;
479 	const Elf_Ehdr *ehdr;
480 	Elf_Addr *where;
481 	Elf_Addr addr, addend;
482 	int i, relacnt;
483 
484 	MPASS(offset != 0);
485 
486 	relacnt = 0;
487 	ehdr = (const Elf_Ehdr *)mapping;
488 	shdr = (const Elf_Shdr *)(mapping + ehdr->e_shoff);
489 	for (i = 0; i < ehdr->e_shnum; i++)
490 	{
491 		switch (shdr[i].sh_type) {
492 		case SHT_REL:
493 			printf("Linux Aarch64 vDSO: unexpected Rel section\n");
494 			break;
495 		case SHT_RELA:
496 			rela = (const Elf_Rela *)(mapping + shdr[i].sh_offset);
497 			relacnt = shdr[i].sh_size / sizeof(*rela);
498 		}
499 	}
500 
501 	for (i = 0; i < relacnt; i++, rela++) {
502 		where = (Elf_Addr *)(mapping + rela->r_offset);
503 		addend = rela->r_addend;
504 		rtype = ELF_R_TYPE(rela->r_info);
505 		symidx = ELF_R_SYM(rela->r_info);
506 
507 		switch (rtype) {
508 		case R_AARCH64_NONE:	/* none */
509 			break;
510 
511 		case R_AARCH64_RELATIVE:	/* B + A */
512 			addr = (Elf_Addr)(mapping + addend);
513 			if (*where != addr)
514 				*where = addr;
515 			break;
516 		default:
517 			printf("Linux Aarch64 vDSO: unexpected relocation type %ld, "
518 			    "symbol index %ld\n", rtype, symidx);
519 		}
520 	}
521 }
522 
523 static Elf_Brandnote linux64_brandnote = {
524 	.hdr.n_namesz	= sizeof(GNU_ABI_VENDOR),
525 	.hdr.n_descsz	= 16,
526 	.hdr.n_type	= 1,
527 	.vendor		= GNU_ABI_VENDOR,
528 	.flags		= BN_TRANSLATE_OSREL,
529 	.trans_osrel	= linux_trans_osrel
530 };
531 
532 static Elf64_Brandinfo linux_glibc2brand = {
533 	.brand		= ELFOSABI_LINUX,
534 	.machine	= EM_AARCH64,
535 	.compat_3_brand	= "Linux",
536 	.interp_path	= "/lib64/ld-linux-x86-64.so.2",
537 	.sysvec		= &elf_linux_sysvec,
538 	.interp_newpath	= NULL,
539 	.brand_note	= &linux64_brandnote,
540 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
541 };
542 
543 Elf64_Brandinfo *linux_brandlist[] = {
544 	&linux_glibc2brand,
545 	NULL
546 };
547 
548 static int
549 linux64_elf_modevent(module_t mod, int type, void *data)
550 {
551 	Elf64_Brandinfo **brandinfo;
552 	struct linux_ioctl_handler**lihp;
553 	int error;
554 
555 	error = 0;
556 	switch(type) {
557 	case MOD_LOAD:
558 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
559 		    ++brandinfo)
560 			if (elf64_insert_brand_entry(*brandinfo) < 0)
561 				error = EINVAL;
562 		if (error == 0) {
563 			SET_FOREACH(lihp, linux_ioctl_handler_set)
564 				linux_ioctl_register_handler(*lihp);
565 			stclohz = (stathz ? stathz : hz);
566 			if (bootverbose)
567 				printf("Linux arm64 ELF exec handler installed\n");
568 		}
569 		break;
570 	case MOD_UNLOAD:
571 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
572 		    ++brandinfo)
573 			if (elf64_brand_inuse(*brandinfo))
574 				error = EBUSY;
575 		if (error == 0) {
576 			for (brandinfo = &linux_brandlist[0];
577 			    *brandinfo != NULL; ++brandinfo)
578 				if (elf64_remove_brand_entry(*brandinfo) < 0)
579 					error = EINVAL;
580 		}
581 		if (error == 0) {
582 			SET_FOREACH(lihp, linux_ioctl_handler_set)
583 				linux_ioctl_unregister_handler(*lihp);
584 			if (bootverbose)
585 				printf("Linux arm64 ELF exec handler removed\n");
586 		} else
587 			printf("Could not deinstall Linux arm64 ELF interpreter entry\n");
588 		break;
589 	default:
590 		return (EOPNOTSUPP);
591 	}
592 	return (error);
593 }
594 
595 static moduledata_t linux64_elf_mod = {
596 	"linux64elf",
597 	linux64_elf_modevent,
598 	0
599 };
600 
601 DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
602 MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1);
603 FEATURE(linux64, "AArch64 Linux 64bit support");
604