xref: /freebsd/sys/arm64/linux/linux_sysvec.c (revision 577b62c2bacc7dfa228591ca3da361e1bc398301)
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 #define	__ELF_WORD_SIZE	64
33 
34 #include <sys/param.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/ktr.h>
41 #include <sys/lock.h>
42 #include <sys/module.h>
43 #include <sys/mutex.h>
44 #include <sys/proc.h>
45 #include <sys/stddef.h>
46 #include <sys/syscallsubr.h>
47 #include <sys/sysctl.h>
48 #include <sys/sysent.h>
49 
50 #include <vm/pmap.h>
51 #include <vm/vm.h>
52 #include <vm/vm_map.h>
53 #include <vm/vm_page.h>
54 
55 #include <arm64/linux/linux.h>
56 #include <arm64/linux/linux_proto.h>
57 #include <compat/linux/linux_dtrace.h>
58 #include <compat/linux/linux_elf.h>
59 #include <compat/linux/linux_emul.h>
60 #include <compat/linux/linux_fork.h>
61 #include <compat/linux/linux_ioctl.h>
62 #include <compat/linux/linux_mib.h>
63 #include <compat/linux/linux_misc.h>
64 #include <compat/linux/linux_signal.h>
65 #include <compat/linux/linux_util.h>
66 #include <compat/linux/linux_vdso.h>
67 
68 #include <arm64/linux/linux_sigframe.h>
69 
70 #include <machine/md_var.h>
71 #include <machine/pcb.h>
72 #ifdef VFP
73 #include <machine/vfp.h>
74 #endif
75 
76 MODULE_VERSION(linux64elf, 1);
77 
78 #define	LINUX_VDSOPAGE_SIZE	PAGE_SIZE * 2
79 #define	LINUX_VDSOPAGE		(VM_MAXUSER_ADDRESS - \
80 				    LINUX_VDSOPAGE_SIZE)
81 #define	LINUX_SHAREDPAGE	(LINUX_VDSOPAGE - PAGE_SIZE)
82 				/*
83 				 * PAGE_SIZE - the size
84 				 * of the native SHAREDPAGE
85 				 */
86 #define	LINUX_USRSTACK		LINUX_SHAREDPAGE
87 #define	LINUX_PS_STRINGS	(LINUX_USRSTACK - \
88 				    sizeof(struct ps_strings))
89 
90 static int linux_szsigcode;
91 static vm_object_t linux_vdso_obj;
92 static char *linux_vdso_mapping;
93 extern char _binary_linux_vdso_so_o_start;
94 extern char _binary_linux_vdso_so_o_end;
95 static vm_offset_t linux_vdso_base;
96 
97 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
98 extern const char *linux_syscallnames[];
99 
100 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
101 
102 static void	linux_vdso_install(const void *param);
103 static void	linux_vdso_deinstall(const void *param);
104 static void	linux_vdso_reloc(char *mapping, Elf_Addr offset);
105 static void	linux_set_syscall_retval(struct thread *td, int error);
106 static int	linux_fetch_syscall_args(struct thread *td);
107 static void	linux_exec_setregs(struct thread *td, struct image_params *imgp,
108 		    uintptr_t stack);
109 static void	linux_exec_sysvec_init(void *param);
110 static int	linux_on_exec_vmspace(struct proc *p,
111 		    struct image_params *imgp);
112 
113 /* DTrace init */
114 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
115 
116 /* DTrace probes */
117 LIN_SDT_PROBE_DEFINE0(sysvec, linux_exec_setregs, todo);
118 LIN_SDT_PROBE_DEFINE0(sysvec, linux_copyout_auxargs, todo);
119 
120 LINUX_VDSO_SYM_CHAR(linux_platform);
121 LINUX_VDSO_SYM_INTPTR(kern_timekeep_base);
122 LINUX_VDSO_SYM_INTPTR(linux_vdso_sigcode);
123 
124 static int
125 linux_fetch_syscall_args(struct thread *td)
126 {
127 	struct proc *p;
128 	struct syscall_args *sa;
129 	register_t *ap;
130 
131 	p = td->td_proc;
132 	ap = td->td_frame->tf_x;
133 	sa = &td->td_sa;
134 
135 	sa->code = td->td_frame->tf_x[8];
136 	sa->original_code = sa->code;
137 	/* LINUXTODO: generic syscall? */
138 	if (sa->code >= p->p_sysent->sv_size)
139 		sa->callp = &p->p_sysent->sv_table[0];
140 	else
141 		sa->callp = &p->p_sysent->sv_table[sa->code];
142 
143 	if (sa->callp->sy_narg > nitems(sa->args))
144 		panic("ARM64TODO: Could we have more than %zu args?",
145 		    nitems(sa->args));
146 	memcpy(sa->args, ap, nitems(sa->args) * sizeof(register_t));
147 
148 	td->td_retval[0] = 0;
149 	return (0);
150 }
151 
152 static void
153 linux_set_syscall_retval(struct thread *td, int error)
154 {
155 
156 	td->td_retval[1] = td->td_frame->tf_x[1];
157 	cpu_set_syscall_retval(td, error);
158 
159 	if (__predict_false(error != 0)) {
160 		if (error != ERESTART && error != EJUSTRETURN)
161 			td->td_frame->tf_x[0] = bsd_to_linux_errno(error);
162 	}
163 }
164 
165 static int
166 linux_copyout_auxargs(struct image_params *imgp, uintptr_t base)
167 {
168 	Elf_Auxargs *args;
169 	Elf_Auxinfo *argarray, *pos;
170 	struct proc *p;
171 	int error, issetugid;
172 
173 	LIN_SDT_PROBE0(sysvec, linux_copyout_auxargs, todo);
174 	p = imgp->proc;
175 
176 	args = (Elf64_Auxargs *)imgp->auxargs;
177 	argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
178 	    M_WAITOK | M_ZERO);
179 
180 	issetugid = p->p_flag & P_SUGID ? 1 : 0;
181 	AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
182 	AUXARGS_ENTRY(pos, LINUX_AT_MINSIGSTKSZ, LINUX_MINSIGSTKSZ);
183 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, *imgp->sysent->sv_hwcap);
184 	AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
185 	AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz);
186 	AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
187 	AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
188 	AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
189 	AUXARGS_ENTRY(pos, AT_BASE, args->base);
190 	AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
191 	AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
192 	AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
193 	AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
194 	AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
195 	AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
196 	AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid);
197 	AUXARGS_ENTRY_PTR(pos, LINUX_AT_RANDOM, imgp->canary);
198 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP2, *imgp->sysent->sv_hwcap2);
199 	if (imgp->execpathp != 0)
200 		AUXARGS_ENTRY_PTR(pos, LINUX_AT_EXECFN, imgp->execpathp);
201 	if (args->execfd != -1)
202 		AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
203 	AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(linux_platform));
204 	AUXARGS_ENTRY(pos, AT_NULL, 0);
205 
206 	free(imgp->auxargs, M_TEMP);
207 	imgp->auxargs = NULL;
208 	KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs"));
209 
210 	error = copyout(argarray, (void *)base,
211 	    sizeof(*argarray) * LINUX_AT_COUNT);
212 	free(argarray, M_TEMP);
213 	return (error);
214 }
215 
216 /*
217  * Reset registers to default values on exec.
218  */
219 static void
220 linux_exec_setregs(struct thread *td, struct image_params *imgp,
221     uintptr_t stack)
222 {
223 	struct trapframe *regs = td->td_frame;
224 	struct pcb *pcb = td->td_pcb;
225 
226 	/* LINUXTODO: validate */
227 	LIN_SDT_PROBE0(sysvec, linux_exec_setregs, todo);
228 
229 	memset(regs, 0, sizeof(*regs));
230 	/* glibc start.S registers function pointer in x0 with atexit. */
231         regs->tf_sp = stack;
232 #if 0	/* LINUXTODO: See if this is used. */
233 	regs->tf_lr = imgp->entry_addr;
234 #else
235         regs->tf_lr = 0xffffffffffffffff;
236 #endif
237         regs->tf_elr = imgp->entry_addr;
238 
239 	pcb->pcb_tpidr_el0 = 0;
240 	pcb->pcb_tpidrro_el0 = 0;
241 	WRITE_SPECIALREG(tpidrro_el0, 0);
242 	WRITE_SPECIALREG(tpidr_el0, 0);
243 
244 #ifdef VFP
245 	vfp_reset_state(td, pcb);
246 #endif
247 
248 	/*
249 	 * Clear debug register state. It is not applicable to the new process.
250 	 */
251 	bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
252 }
253 
254 int
255 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
256 {
257 	struct l_sigframe *frame;
258 	ucontext_t uc;
259 	struct trapframe *tf;
260 	int error;
261 
262 	tf = td->td_frame;
263 	frame = (struct l_sigframe *)tf->tf_sp;
264 
265 	if (copyin((void *)&frame->uc, &uc, sizeof(uc)))
266 		return (EFAULT);
267 
268 	error = set_mcontext(td, &uc.uc_mcontext);
269 	if (error != 0)
270 		return (error);
271 
272 	/* Restore signal mask. */
273 	kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
274 
275 	return (EJUSTRETURN);
276 }
277 
278 static void
279 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
280 {
281 	struct thread *td;
282 	struct proc *p;
283 	struct trapframe *tf;
284 	struct l_sigframe *fp, *frame;
285 	struct l_fpsimd_context *fpsimd;
286 	struct l_esr_context *esr;
287 	l_stack_t uc_stack;
288 	ucontext_t uc;
289 	uint8_t *scr;
290 	struct sigacts *psp;
291 	int onstack, sig, issiginfo;
292 
293 	td = curthread;
294 	p = td->td_proc;
295 	PROC_LOCK_ASSERT(p, MA_OWNED);
296 
297 	sig = ksi->ksi_signo;
298 	psp = p->p_sigacts;
299 	mtx_assert(&psp->ps_mtx, MA_OWNED);
300 
301 	tf = td->td_frame;
302 	onstack = sigonstack(tf->tf_sp);
303 	issiginfo = SIGISMEMBER(psp->ps_siginfo, sig);
304 
305 	CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
306 	    catcher, sig);
307 
308 	/* Allocate and validate space for the signal handler context. */
309 	if ((td->td_pflags & TDP_ALTSTACK) != 0 && !onstack &&
310 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
311 		fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
312 		    td->td_sigstk.ss_size);
313 #if defined(COMPAT_43)
314 		td->td_sigstk.ss_flags |= SS_ONSTACK;
315 #endif
316 	} else {
317 		fp = (struct l_sigframe *)td->td_frame->tf_sp;
318 	}
319 
320 	/* Make room, keeping the stack aligned */
321 	fp--;
322 	fp = (struct l_sigframe *)STACKALIGN(fp);
323 
324 	get_mcontext(td, &uc.uc_mcontext, 0);
325 	uc.uc_sigmask = *mask;
326 
327 	uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
328 	uc_stack.ss_size = td->td_sigstk.ss_size;
329 	uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) != 0 ?
330 	    (onstack ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
331 	mtx_unlock(&psp->ps_mtx);
332 	PROC_UNLOCK(td->td_proc);
333 
334 	/* Fill in the frame to copy out */
335 	frame = malloc(sizeof(*frame), M_LINUX, M_WAITOK | M_ZERO);
336 
337 	memcpy(&frame->sf.sf_uc.uc_sc.regs, tf->tf_x, sizeof(tf->tf_x));
338 	frame->sf.sf_uc.uc_sc.regs[30] = tf->tf_lr;
339 	frame->sf.sf_uc.uc_sc.sp = tf->tf_sp;
340 	frame->sf.sf_uc.uc_sc.pc = tf->tf_lr;
341 	frame->sf.sf_uc.uc_sc.pstate = tf->tf_spsr;
342 	frame->sf.sf_uc.uc_sc.fault_address = (register_t)ksi->ksi_addr;
343 
344 	/* Stack frame for unwinding */
345 	frame->fp = tf->tf_x[29];
346 	frame->lr = tf->tf_lr;
347 
348 	/* Translate the signal. */
349 	sig = bsd_to_linux_signal(sig);
350 	siginfo_to_lsiginfo(&ksi->ksi_info, &frame->sf.sf_si, sig);
351 	bsd_to_linux_sigset(mask, &frame->sf.sf_uc.uc_sigmask);
352 
353 	/*
354 	 * Prepare fpsimd & esr. Does not check sizes, as
355 	 * __reserved is big enougth.
356 	 */
357 	scr = (uint8_t *)&frame->sf.sf_uc.uc_sc.__reserved;
358 #ifdef VFP
359 	fpsimd = (struct l_fpsimd_context *) scr;
360 	fpsimd->head.magic = L_FPSIMD_MAGIC;
361 	fpsimd->head.size = sizeof(struct l_fpsimd_context);
362 	fpsimd->fpsr = uc.uc_mcontext.mc_fpregs.fp_sr;
363 	fpsimd->fpcr = uc.uc_mcontext.mc_fpregs.fp_cr;
364 
365 	memcpy(fpsimd->vregs, &uc.uc_mcontext.mc_fpregs.fp_q,
366 	    sizeof(uc.uc_mcontext.mc_fpregs.fp_q));
367 	scr += roundup(sizeof(struct l_fpsimd_context), 16);
368 #endif
369 	if (ksi->ksi_addr != 0) {
370 		esr = (struct l_esr_context *) scr;
371 		esr->head.magic = L_ESR_MAGIC;
372 		esr->head.size = sizeof(struct l_esr_context);
373 		esr->esr = tf->tf_esr;
374 	}
375 
376 	memcpy(&frame->sf.sf_uc.uc_stack, &uc_stack, sizeof(uc_stack));
377 	memcpy(&frame->uc, &uc, sizeof(uc));
378 
379 	/* Copy the sigframe out to the user's stack. */
380 	if (copyout(frame, fp, sizeof(*fp)) != 0) {
381 		/* Process has trashed its stack. Kill it. */
382 		free(frame, M_LINUX);
383 		CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
384 		PROC_LOCK(p);
385 		sigexit(td, SIGILL);
386 	}
387 	free(frame, M_LINUX);
388 
389 	tf->tf_x[0]= sig;
390 	if (issiginfo) {
391 		tf->tf_x[1] = (register_t)&fp->sf.sf_si;
392 		tf->tf_x[2] = (register_t)&fp->sf.sf_uc;
393 	} else {
394 		tf->tf_x[1] = 0;
395 		tf->tf_x[2] = 0;
396 	}
397 	tf->tf_x[8] = (register_t)catcher;
398 	tf->tf_sp = (register_t)fp;
399 	tf->tf_elr = (register_t)linux_vdso_sigcode;
400 
401 	CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_elr,
402 	    tf->tf_sp);
403 
404 	PROC_LOCK(p);
405 	mtx_lock(&psp->ps_mtx);
406 }
407 
408 struct sysentvec elf_linux_sysvec = {
409 	.sv_size	= LINUX_SYS_MAXSYSCALL,
410 	.sv_table	= linux_sysent,
411 	.sv_fixup	= __elfN(freebsd_fixup),
412 	.sv_sendsig	= linux_rt_sendsig,
413 	.sv_sigcode	= &_binary_linux_vdso_so_o_start,
414 	.sv_szsigcode	= &linux_szsigcode,
415 	.sv_name	= "Linux ELF64",
416 	.sv_coredump	= elf64_coredump,
417 	.sv_elf_core_osabi = ELFOSABI_NONE,
418 	.sv_elf_core_abi_vendor = LINUX_ABI_VENDOR,
419 	.sv_elf_core_prepare_notes = linux64_prepare_notes,
420 	.sv_imgact_try	= linux_exec_imgact_try,
421 	.sv_minsigstksz	= LINUX_MINSIGSTKSZ,
422 	.sv_minuser	= VM_MIN_ADDRESS,
423 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
424 	.sv_usrstack	= LINUX_USRSTACK,
425 	.sv_psstrings	= LINUX_PS_STRINGS,
426 	.sv_psstringssz	= sizeof(struct ps_strings),
427 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
428 	.sv_copyout_auxargs = linux_copyout_auxargs,
429 	.sv_copyout_strings = __linuxN(copyout_strings),
430 	.sv_setregs	= linux_exec_setregs,
431 	.sv_fixlimit	= NULL,
432 	.sv_maxssiz	= NULL,
433 	.sv_flags	= SV_ABI_LINUX | SV_LP64 | SV_SHP | SV_SIG_DISCIGN |
434 	    SV_SIG_WAITNDQ | SV_TIMEKEEP,
435 	.sv_set_syscall_retval = linux_set_syscall_retval,
436 	.sv_fetch_syscall_args = linux_fetch_syscall_args,
437 	.sv_syscallnames = linux_syscallnames,
438 	.sv_shared_page_base = LINUX_SHAREDPAGE,
439 	.sv_shared_page_len = PAGE_SIZE,
440 	.sv_schedtail	= linux_schedtail,
441 	.sv_thread_detach = linux_thread_detach,
442 	.sv_trap	= NULL,
443 	.sv_hwcap	= &elf_hwcap,
444 	.sv_hwcap2	= &elf_hwcap2,
445 	.sv_onexec	= linux_on_exec_vmspace,
446 	.sv_onexit	= linux_on_exit,
447 	.sv_ontdexit	= linux_thread_dtor,
448 	.sv_setid_allowed = &linux_setid_allowed_query,
449 };
450 
451 static int
452 linux_on_exec_vmspace(struct proc *p, struct image_params *imgp)
453 {
454 	int error;
455 
456 	error = linux_map_vdso(p, linux_vdso_obj, linux_vdso_base,
457 	    LINUX_VDSOPAGE_SIZE, imgp);
458 	if (error == 0)
459 		linux_on_exec(p, imgp);
460 	return (error);
461 }
462 
463 /*
464  * linux_vdso_install() and linux_exec_sysvec_init() must be called
465  * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
466  */
467 static void
468 linux_exec_sysvec_init(void *param)
469 {
470 	l_uintptr_t *ktimekeep_base;
471 	struct sysentvec *sv;
472 	ptrdiff_t tkoff;
473 
474 	sv = param;
475 	/* Fill timekeep_base */
476 	exec_sysvec_init(sv);
477 
478 	tkoff = kern_timekeep_base - linux_vdso_base;
479 	ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
480 	*ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
481 }
482 SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
483     linux_exec_sysvec_init, &elf_linux_sysvec);
484 
485 static void
486 linux_vdso_install(const void *param)
487 {
488 	char *vdso_start = &_binary_linux_vdso_so_o_start;
489 	char *vdso_end = &_binary_linux_vdso_so_o_end;
490 
491 	linux_szsigcode = vdso_end - vdso_start;
492 	MPASS(linux_szsigcode <= LINUX_VDSOPAGE_SIZE);
493 
494 	linux_vdso_base = LINUX_VDSOPAGE;
495 
496 	__elfN(linux_vdso_fixup)(vdso_start, linux_vdso_base);
497 
498 	linux_vdso_obj = __elfN(linux_shared_page_init)
499 	    (&linux_vdso_mapping, LINUX_VDSOPAGE_SIZE);
500 	bcopy(vdso_start, linux_vdso_mapping, linux_szsigcode);
501 
502 	linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
503 }
504 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
505     linux_vdso_install, NULL);
506 
507 static void
508 linux_vdso_deinstall(const void *param)
509 {
510 
511 	__elfN(linux_shared_page_fini)(linux_vdso_obj,
512 	    linux_vdso_mapping, LINUX_VDSOPAGE_SIZE);
513 }
514 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
515     linux_vdso_deinstall, NULL);
516 
517 static void
518 linux_vdso_reloc(char *mapping, Elf_Addr offset)
519 {
520 	Elf_Size rtype, symidx;
521 	const Elf_Rela *rela;
522 	const Elf_Shdr *shdr;
523 	const Elf_Ehdr *ehdr;
524 	Elf_Addr *where;
525 	Elf_Addr addr, addend;
526 	int i, relacnt;
527 
528 	MPASS(offset != 0);
529 
530 	relacnt = 0;
531 	ehdr = (const Elf_Ehdr *)mapping;
532 	shdr = (const Elf_Shdr *)(mapping + ehdr->e_shoff);
533 	for (i = 0; i < ehdr->e_shnum; i++)
534 	{
535 		switch (shdr[i].sh_type) {
536 		case SHT_REL:
537 			printf("Linux Aarch64 vDSO: unexpected Rel section\n");
538 			break;
539 		case SHT_RELA:
540 			rela = (const Elf_Rela *)(mapping + shdr[i].sh_offset);
541 			relacnt = shdr[i].sh_size / sizeof(*rela);
542 		}
543 	}
544 
545 	for (i = 0; i < relacnt; i++, rela++) {
546 		where = (Elf_Addr *)(mapping + rela->r_offset);
547 		addend = rela->r_addend;
548 		rtype = ELF_R_TYPE(rela->r_info);
549 		symidx = ELF_R_SYM(rela->r_info);
550 
551 		switch (rtype) {
552 		case R_AARCH64_NONE:	/* none */
553 			break;
554 
555 		case R_AARCH64_RELATIVE:	/* B + A */
556 			addr = (Elf_Addr)(mapping + addend);
557 			if (*where != addr)
558 				*where = addr;
559 			break;
560 		default:
561 			printf("Linux Aarch64 vDSO: unexpected relocation type %ld, "
562 			    "symbol index %ld\n", rtype, symidx);
563 		}
564 	}
565 }
566 
567 static Elf_Brandnote linux64_brandnote = {
568 	.hdr.n_namesz	= sizeof(GNU_ABI_VENDOR),
569 	.hdr.n_descsz	= 16,
570 	.hdr.n_type	= 1,
571 	.vendor		= GNU_ABI_VENDOR,
572 	.flags		= BN_TRANSLATE_OSREL,
573 	.trans_osrel	= linux_trans_osrel
574 };
575 
576 static Elf64_Brandinfo linux_glibc2brand = {
577 	.brand		= ELFOSABI_LINUX,
578 	.machine	= EM_AARCH64,
579 	.compat_3_brand	= "Linux",
580 	.emul_path	= linux_emul_path,
581 	.interp_path	= "/lib64/ld-linux-x86-64.so.2",
582 	.sysvec		= &elf_linux_sysvec,
583 	.interp_newpath	= NULL,
584 	.brand_note	= &linux64_brandnote,
585 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
586 };
587 
588 Elf64_Brandinfo *linux_brandlist[] = {
589 	&linux_glibc2brand,
590 	NULL
591 };
592 
593 static int
594 linux64_elf_modevent(module_t mod, int type, void *data)
595 {
596 	Elf64_Brandinfo **brandinfo;
597 	struct linux_ioctl_handler**lihp;
598 	int error;
599 
600 	error = 0;
601 	switch(type) {
602 	case MOD_LOAD:
603 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
604 		    ++brandinfo)
605 			if (elf64_insert_brand_entry(*brandinfo) < 0)
606 				error = EINVAL;
607 		if (error == 0) {
608 			SET_FOREACH(lihp, linux_ioctl_handler_set)
609 				linux_ioctl_register_handler(*lihp);
610 			stclohz = (stathz ? stathz : hz);
611 			if (bootverbose)
612 				printf("Linux arm64 ELF exec handler installed\n");
613 		}
614 		break;
615 	case MOD_UNLOAD:
616 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
617 		    ++brandinfo)
618 			if (elf64_brand_inuse(*brandinfo))
619 				error = EBUSY;
620 		if (error == 0) {
621 			for (brandinfo = &linux_brandlist[0];
622 			    *brandinfo != NULL; ++brandinfo)
623 				if (elf64_remove_brand_entry(*brandinfo) < 0)
624 					error = EINVAL;
625 		}
626 		if (error == 0) {
627 			SET_FOREACH(lihp, linux_ioctl_handler_set)
628 				linux_ioctl_unregister_handler(*lihp);
629 			if (bootverbose)
630 				printf("Linux arm64 ELF exec handler removed\n");
631 		} else
632 			printf("Could not deinstall Linux arm64 ELF interpreter entry\n");
633 		break;
634 	default:
635 		return (EOPNOTSUPP);
636 	}
637 	return (error);
638 }
639 
640 static moduledata_t linux64_elf_mod = {
641 	"linux64elf",
642 	linux64_elf_modevent,
643 	0
644 };
645 
646 DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
647 MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1);
648 FEATURE(linux64, "AArch64 Linux 64bit support");
649