/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1994-1996 Søren Schmidt
 * Copyright (c) 2018 Turing Robotic Industries Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#define __ELF_WORD_SIZE 64

#include <sys/param.h>
#include <sys/elf.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/imgact_elf.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/stddef.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>

#include <vm/vm.h>
#include <vm/vm_param.h>

#include <arm64/linux/linux.h>
#include <arm64/linux/linux_proto.h>
#include <compat/linux/linux_elf.h>
#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_fork.h>
#include <compat/linux/linux_ioctl.h>
#include <compat/linux/linux_mib.h>
#include <compat/linux/linux_misc.h>
#include <compat/linux/linux_signal.h>
#include <compat/linux/linux_util.h>
#include <compat/linux/linux_vdso.h>

#include <arm64/linux/linux_sigframe.h>

#include <machine/md_var.h>
#include <machine/pcb.h>
#ifdef VFP
#include <machine/vfp.h>
#endif

MODULE_VERSION(linux64elf, 1);

#define LINUX_VDSOPAGE_SIZE     PAGE_SIZE * 2
#define LINUX_VDSOPAGE          (VM_MAXUSER_ADDRESS - \
                                    LINUX_VDSOPAGE_SIZE)
#define LINUX_SHAREDPAGE        (LINUX_VDSOPAGE - PAGE_SIZE)
                                /*
                                 * PAGE_SIZE - the size
                                 * of the native SHAREDPAGE
                                 */
#define LINUX_USRSTACK          LINUX_SHAREDPAGE
#define LINUX_PS_STRINGS        (LINUX_USRSTACK - \
                                    sizeof(struct ps_strings))

static int linux_szsigcode;
static vm_object_t linux_vdso_obj;
static char *linux_vdso_mapping;
extern char _binary_linux_vdso_so_o_start;
extern char _binary_linux_vdso_so_o_end;
static vm_offset_t linux_vdso_base;

extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
extern const char *linux_syscallnames[];

SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);

static void     linux_vdso_install(const void *param);
static void     linux_vdso_deinstall(const void *param);
static void     linux_vdso_reloc(char *mapping, Elf_Addr offset);
static void     linux_set_syscall_retval(struct thread *td, int error);
static int      linux_fetch_syscall_args(struct thread *td);
static void     linux_exec_setregs(struct thread *td, struct image_params *imgp,
                    uintptr_t stack);
static void     linux_exec_sysvec_init(void *param);
static int      linux_on_exec_vmspace(struct proc *p,
                    struct image_params *imgp);

LINUX_VDSO_SYM_CHAR(linux_platform);
LINUX_VDSO_SYM_INTPTR(kern_timekeep_base);
LINUX_VDSO_SYM_INTPTR(__user_rt_sigreturn);

static int
linux_fetch_syscall_args(struct thread *td)
{
        struct proc *p;
        struct syscall_args *sa;
        register_t *ap;

        p = td->td_proc;
        ap = td->td_frame->tf_x;
        sa = &td->td_sa;

        sa->code = td->td_frame->tf_x[8];
        sa->original_code = sa->code;

        if (sa->code >= p->p_sysent->sv_size)
                sa->callp = &nosys_sysent;
        else
                sa->callp = &p->p_sysent->sv_table[sa->code];

        if (sa->callp->sy_narg > nitems(sa->args))
                panic("ARM64TODO: Could we have more than %zu args?",
                    nitems(sa->args));
        memcpy(sa->args, ap, nitems(sa->args) * sizeof(register_t));

        td->td_retval[0] = 0;
        return (0);
}

static void
linux_set_syscall_retval(struct thread *td, int error)
{

        td->td_retval[1] = td->td_frame->tf_x[1];
        cpu_set_syscall_retval(td, error);

        if (__predict_false(error != 0)) {
                if (error != ERESTART && error != EJUSTRETURN)
                        td->td_frame->tf_x[0] = bsd_to_linux_errno(error);
        }
}

void
linux64_arch_copyout_auxargs(struct image_params *imgp, Elf_Auxinfo **pos)
{

        AUXARGS_ENTRY((*pos), LINUX_AT_SYSINFO_EHDR, linux_vdso_base);
        AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP, *imgp->sysent->sv_hwcap);
        AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP2, *imgp->sysent->sv_hwcap2);
        AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP3, *imgp->sysent->sv_hwcap3);
        AUXARGS_ENTRY((*pos), LINUX_AT_HWCAP4, *imgp->sysent->sv_hwcap4);
        AUXARGS_ENTRY((*pos), LINUX_AT_PLATFORM, PTROUT(linux_platform));
}

/*
 * Reset registers to default values on exec.
 */
static void
linux_exec_setregs(struct thread *td, struct image_params *imgp,
    uintptr_t stack)
{
        struct trapframe *regs = td->td_frame;
        struct pcb *pcb = td->td_pcb;

        memset(regs, 0, sizeof(*regs));
        regs->tf_sp = stack;
        regs->tf_elr = imgp->entry_addr;
        pcb->pcb_tpidr_el0 = 0;
        pcb->pcb_tpidrro_el0 = 0;
        WRITE_SPECIALREG(tpidrro_el0, 0);
        WRITE_SPECIALREG(tpidr_el0, 0);

#ifdef VFP
        vfp_reset_state(td, pcb);
#endif

        /*
         * Clear debug register state. It is not applicable to the new process.
         */
        bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
}

static bool
linux_parse_sigreturn_ctx(struct thread *td, struct l_sigcontext *sc)
{
        struct l_fpsimd_context *fpsimd;
        struct _l_aarch64_ctx *ctx;
        int offset;

        offset = 0;
        while (1) {
                /* The offset must be 16 byte aligned */
                if ((offset & 15) != 0)
                        return (false);

                /* Check for buffer overflow of the ctx */
                if ((offset + sizeof(*ctx)) >
                    sizeof(sc->__reserved))
                        return (false);

                ctx = (struct _l_aarch64_ctx *)&sc->__reserved[offset];

                /* Check for buffer overflow of the data */
                if ((offset + ctx->size) > sizeof(sc->__reserved))
                        return (false);

                switch(ctx->magic) {
                case 0:
                        if (ctx->size != 0)
                                return (false);
                        return (true);
                case L_ESR_MAGIC:
                        /* Ignore */
                        break;
#ifdef VFP
                case L_FPSIMD_MAGIC:
                        fpsimd = (struct l_fpsimd_context *)ctx;

                        /*
                         * Discard any vfp state for the current thread, we
                         * are about to override it.
                         */
                        critical_enter();
                        vfp_discard(td);
                        critical_exit();

                        td->td_pcb->pcb_fpustate.vfp_fpcr = fpsimd->fpcr;
                        td->td_pcb->pcb_fpustate.vfp_fpsr = fpsimd->fpsr;
                        memcpy(td->td_pcb->pcb_fpustate.vfp_regs,
                            fpsimd->vregs, sizeof(fpsimd->vregs));

                        break;
#endif
                default:
                        return (false);
                }

                offset += ctx->size;
        }

}

int
linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
{
        struct l_rt_sigframe *sf;
        struct l_sigframe *frame;
        struct trapframe *tf;
        sigset_t bmask;
        int error;

        sf = malloc(sizeof(*sf), M_LINUX, M_WAITOK | M_ZERO);

        tf = td->td_frame;
        frame = (struct l_sigframe *)tf->tf_sp;
        error = copyin((void *)&frame->sf, sf, sizeof(*sf));
        if (error != 0) {
                free(sf, M_LINUX);
                return (error);
        }

        memcpy(tf->tf_x, sf->sf_uc.uc_sc.regs, sizeof(tf->tf_x));
        tf->tf_lr = sf->sf_uc.uc_sc.regs[30];
        tf->tf_sp = sf->sf_uc.uc_sc.sp;
        tf->tf_elr = sf->sf_uc.uc_sc.pc;

        if ((sf->sf_uc.uc_sc.pstate & PSR_M_MASK) != PSR_M_EL0t ||
            (sf->sf_uc.uc_sc.pstate & PSR_AARCH32) != 0 ||
            (sf->sf_uc.uc_sc.pstate & PSR_DAIF) !=
            (td->td_frame->tf_spsr & PSR_DAIF))
                goto einval;
        tf->tf_spsr = sf->sf_uc.uc_sc.pstate;

        if (!linux_parse_sigreturn_ctx(td, &sf->sf_uc.uc_sc))
                goto einval;

        /* Restore signal mask. */
        linux_to_bsd_sigset(&sf->sf_uc.uc_sigmask, &bmask);
        kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
        free(sf, M_LINUX);

        return (EJUSTRETURN);
einval:
        free(sf, M_LINUX);
        return (EINVAL);
}

static void
linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
        struct thread *td;
        struct proc *p;
        struct trapframe *tf;
        struct l_sigframe *fp, *frame;
        struct l_fpsimd_context *fpsimd;
        struct l_esr_context *esr;
        l_stack_t uc_stack;
        ucontext_t uc;
        uint8_t *scr;
        struct sigacts *psp;
        int onstack, sig, issiginfo;

        td = curthread;
        p = td->td_proc;
        PROC_LOCK_ASSERT(p, MA_OWNED);

        sig = ksi->ksi_signo;
        psp = p->p_sigacts;
        mtx_assert(&psp->ps_mtx, MA_OWNED);

        tf = td->td_frame;
        onstack = sigonstack(tf->tf_sp);
        issiginfo = SIGISMEMBER(psp->ps_siginfo, sig);

        CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
            catcher, sig);

        /* Allocate and validate space for the signal handler context. */
        if ((td->td_pflags & TDP_ALTSTACK) != 0 && !onstack &&
            SIGISMEMBER(psp->ps_sigonstack, sig)) {
                fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
                    td->td_sigstk.ss_size);
#if defined(COMPAT_43)
                td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
        } else {
                fp = (struct l_sigframe *)td->td_frame->tf_sp;
        }

        /* Make room, keeping the stack aligned */
        fp--;
        fp = STACKALIGN(fp);

        get_mcontext(td, &uc.uc_mcontext, 0);
        uc.uc_sigmask = *mask;

        uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
        uc_stack.ss_size = td->td_sigstk.ss_size;
        uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) != 0 ?
            (onstack ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
        mtx_unlock(&psp->ps_mtx);
        PROC_UNLOCK(td->td_proc);

        /* Fill in the frame to copy out */
        frame = malloc(sizeof(*frame), M_LINUX, M_WAITOK | M_ZERO);

        memcpy(&frame->sf.sf_uc.uc_sc.regs, tf->tf_x, sizeof(tf->tf_x));
        frame->sf.sf_uc.uc_sc.regs[30] = tf->tf_lr;
        frame->sf.sf_uc.uc_sc.sp = tf->tf_sp;
        frame->sf.sf_uc.uc_sc.pc = tf->tf_elr;
        frame->sf.sf_uc.uc_sc.pstate = tf->tf_spsr;
        frame->sf.sf_uc.uc_sc.fault_address = (register_t)ksi->ksi_addr;

        /* Stack frame for unwinding */
        frame->fp = tf->tf_x[29];
        frame->lr = tf->tf_elr;

        /* Translate the signal. */
        sig = bsd_to_linux_signal(sig);
        siginfo_to_lsiginfo(&ksi->ksi_info, &frame->sf.sf_si, sig);
        bsd_to_linux_sigset(mask, &frame->sf.sf_uc.uc_sigmask);

        /*
         * Prepare fpsimd & esr. Does not check sizes, as
         * __reserved is big enougth.
         */
        scr = (uint8_t *)&frame->sf.sf_uc.uc_sc.__reserved;
#ifdef VFP
        fpsimd = (struct l_fpsimd_context *) scr;
        fpsimd->head.magic = L_FPSIMD_MAGIC;
        fpsimd->head.size = sizeof(struct l_fpsimd_context);
        fpsimd->fpsr = uc.uc_mcontext.mc_fpregs.fp_sr;
        fpsimd->fpcr = uc.uc_mcontext.mc_fpregs.fp_cr;

        memcpy(fpsimd->vregs, &uc.uc_mcontext.mc_fpregs.fp_q,
            sizeof(uc.uc_mcontext.mc_fpregs.fp_q));
        scr += roundup(sizeof(struct l_fpsimd_context), 16);
#endif
        if (ksi->ksi_addr != 0) {
                esr = (struct l_esr_context *) scr;
                esr->head.magic = L_ESR_MAGIC;
                esr->head.size = sizeof(struct l_esr_context);
                esr->esr = tf->tf_esr;
        }

        memcpy(&frame->sf.sf_uc.uc_stack, &uc_stack, sizeof(uc_stack));

        /* Copy the sigframe out to the user's stack. */
        if (copyout(frame, fp, sizeof(*fp)) != 0) {
                /* Process has trashed its stack. Kill it. */
                free(frame, M_LINUX);
                CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
                PROC_LOCK(p);
                sigexit(td, SIGILL);
        }
        free(frame, M_LINUX);

        tf->tf_x[0]= sig;
        if (issiginfo) {
                tf->tf_x[1] = (register_t)&fp->sf.sf_si;
                tf->tf_x[2] = (register_t)&fp->sf.sf_uc;
        } else {
                tf->tf_x[1] = 0;
                tf->tf_x[2] = 0;
        }
        tf->tf_x[29] = (register_t)&fp->fp;
        tf->tf_elr = (register_t)catcher;
        tf->tf_sp = (register_t)fp;
        tf->tf_lr = (register_t)__user_rt_sigreturn;

        CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_elr,
            tf->tf_sp);

        PROC_LOCK(p);
        mtx_lock(&psp->ps_mtx);
}

struct sysentvec elf_linux_sysvec = {
        .sv_size        = LINUX_SYS_MAXSYSCALL,
        .sv_table       = linux_sysent,
        .sv_fixup       = __elfN(freebsd_fixup),
        .sv_sendsig     = linux_rt_sendsig,
        .sv_sigcode     = &_binary_linux_vdso_so_o_start,
        .sv_szsigcode   = &linux_szsigcode,
        .sv_name        = "Linux ELF64",
        .sv_coredump    = elf64_coredump,
        .sv_elf_core_osabi = ELFOSABI_NONE,
        .sv_elf_core_abi_vendor = LINUX_ABI_VENDOR,
        .sv_elf_core_prepare_notes = linux64_prepare_notes,
        .sv_minsigstksz = LINUX_MINSIGSTKSZ,
        .sv_minuser     = VM_MIN_ADDRESS,
        .sv_maxuser     = VM_MAXUSER_ADDRESS,
        .sv_usrstack    = LINUX_USRSTACK,
        .sv_psstrings   = LINUX_PS_STRINGS,
        .sv_psstringssz = sizeof(struct ps_strings),
        .sv_stackprot   = VM_PROT_READ | VM_PROT_WRITE,
        .sv_copyout_auxargs = __linuxN(copyout_auxargs),
        .sv_copyout_strings = __linuxN(copyout_strings),
        .sv_setregs     = linux_exec_setregs,
        .sv_fixlimit    = NULL,
        .sv_maxssiz     = NULL,
        .sv_flags       = SV_ABI_LINUX | SV_LP64 | SV_SHP | SV_SIG_DISCIGN |
            SV_SIG_WAITNDQ | SV_TIMEKEEP,
        .sv_set_syscall_retval = linux_set_syscall_retval,
        .sv_fetch_syscall_args = linux_fetch_syscall_args,
        .sv_syscallnames = linux_syscallnames,
        .sv_shared_page_base = LINUX_SHAREDPAGE,
        .sv_shared_page_len = PAGE_SIZE,
        .sv_schedtail   = linux_schedtail,
        .sv_thread_detach = linux_thread_detach,
        .sv_trap        = NULL,
        .sv_hwcap       = &linux_elf_hwcap,
        .sv_hwcap2      = &linux_elf_hwcap2,
        .sv_hwcap3      = &linux_elf_hwcap3,
        .sv_hwcap4      = &linux_elf_hwcap4,
        .sv_onexec      = linux_on_exec_vmspace,
        .sv_onexit      = linux_on_exit,
        .sv_ontdexit    = linux_thread_dtor,
        .sv_setid_allowed = &linux_setid_allowed_query,
};

static int
linux_on_exec_vmspace(struct proc *p, struct image_params *imgp)
{
        int error;

        error = linux_map_vdso(p, linux_vdso_obj, linux_vdso_base,
            LINUX_VDSOPAGE_SIZE, imgp);
        if (error == 0)
                error = linux_on_exec(p, imgp);
        return (error);
}

/*
 * linux_vdso_install() and linux_exec_sysvec_init() must be called
 * after exec_sysvec_init() which is SI_SUB_EXEC (SI_ORDER_ANY).
 */
static void
linux_exec_sysvec_init(void *param)
{
        l_uintptr_t *ktimekeep_base;
        struct sysentvec *sv;
        ptrdiff_t tkoff;

        sv = param;
        /* Fill timekeep_base */
        exec_sysvec_init(sv);

        tkoff = kern_timekeep_base - linux_vdso_base;
        ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
        *ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
}
SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
    linux_exec_sysvec_init, &elf_linux_sysvec);

static void
linux_vdso_install(const void *param)
{
        char *vdso_start = &_binary_linux_vdso_so_o_start;
        char *vdso_end = &_binary_linux_vdso_so_o_end;

        linux_szsigcode = vdso_end - vdso_start;
        MPASS(linux_szsigcode <= LINUX_VDSOPAGE_SIZE);

        linux_vdso_base = LINUX_VDSOPAGE;

        __elfN(linux_vdso_fixup)(vdso_start, linux_vdso_base);

        linux_vdso_obj = __elfN(linux_shared_page_init)
            (&linux_vdso_mapping, LINUX_VDSOPAGE_SIZE);
        bcopy(vdso_start, linux_vdso_mapping, linux_szsigcode);

        linux_vdso_reloc(linux_vdso_mapping, linux_vdso_base);
}
SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC + 1, SI_ORDER_FIRST,
    linux_vdso_install, NULL);

static void
linux_vdso_deinstall(const void *param)
{

        __elfN(linux_shared_page_fini)(linux_vdso_obj,
            linux_vdso_mapping, LINUX_VDSOPAGE_SIZE);
}
SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
    linux_vdso_deinstall, NULL);

static void
linux_vdso_reloc(char *mapping, Elf_Addr offset)
{
        Elf_Size rtype, symidx;
        const Elf_Rela *rela;
        const Elf_Shdr *shdr;
        const Elf_Ehdr *ehdr;
        Elf_Addr *where;
        Elf_Addr addr, addend;
        int i, relacnt;

        MPASS(offset != 0);

        relacnt = 0;
        ehdr = (const Elf_Ehdr *)mapping;
        shdr = (const Elf_Shdr *)(mapping + ehdr->e_shoff);
        for (i = 0; i < ehdr->e_shnum; i++)
        {
                switch (shdr[i].sh_type) {
                case SHT_REL:
                        printf("Linux Aarch64 vDSO: unexpected Rel section\n");
                        break;
                case SHT_RELA:
                        rela = (const Elf_Rela *)(mapping + shdr[i].sh_offset);
                        relacnt = shdr[i].sh_size / sizeof(*rela);
                }
        }

        for (i = 0; i < relacnt; i++, rela++) {
                where = (Elf_Addr *)(mapping + rela->r_offset);
                addend = rela->r_addend;
                rtype = ELF_R_TYPE(rela->r_info);
                symidx = ELF_R_SYM(rela->r_info);

                switch (rtype) {
                case R_AARCH64_NONE:    /* none */
                        break;

                case R_AARCH64_RELATIVE:        /* B + A */
                        addr = (Elf_Addr)(mapping + addend);
                        if (*where != addr)
                                *where = addr;
                        break;
                default:
                        printf("Linux Aarch64 vDSO: unexpected relocation type %ld, "
                            "symbol index %ld\n", rtype, symidx);
                }
        }
}

static const Elf_Brandnote linux64_brandnote = {
        .hdr.n_namesz   = sizeof(GNU_ABI_VENDOR),
        .hdr.n_descsz   = 16,
        .hdr.n_type     = 1,
        .vendor         = GNU_ABI_VENDOR,
        .flags          = BN_TRANSLATE_OSREL,
        .trans_osrel    = linux_trans_osrel
};

static const Elf64_Brandinfo linux_glibc2brand = {
        .brand          = ELFOSABI_LINUX,
        .machine        = EM_AARCH64,
        .compat_3_brand = "Linux",
        .interp_path    = "/lib64/ld-linux-x86-64.so.2",
        .sysvec         = &elf_linux_sysvec,
        .interp_newpath = NULL,
        .brand_note     = &linux64_brandnote,
        .flags          = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
};

const Elf64_Brandinfo *linux_brandlist[] = {
        &linux_glibc2brand,
        NULL
};

static int
linux64_elf_modevent(module_t mod, int type, void *data)
{
        const Elf64_Brandinfo **brandinfo;
        struct linux_ioctl_handler **lihp;
        int error;

        error = 0;
        switch(type) {
        case MOD_LOAD:
                for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
                    ++brandinfo)
                        if (elf64_insert_brand_entry(*brandinfo) < 0)
                                error = EINVAL;
                if (error == 0) {
                        SET_FOREACH(lihp, linux_ioctl_handler_set)
                                linux_ioctl_register_handler(*lihp);
                        stclohz = (stathz ? stathz : hz);
                        if (bootverbose)
                                printf("Linux arm64 ELF exec handler installed\n");
                }
                break;
        case MOD_UNLOAD:
                for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
                    ++brandinfo)
                        if (elf64_brand_inuse(*brandinfo))
                                error = EBUSY;
                if (error == 0) {
                        for (brandinfo = &linux_brandlist[0];
                            *brandinfo != NULL; ++brandinfo)
                                if (elf64_remove_brand_entry(*brandinfo) < 0)
                                        error = EINVAL;
                }
                if (error == 0) {
                        SET_FOREACH(lihp, linux_ioctl_handler_set)
                                linux_ioctl_unregister_handler(*lihp);
                        if (bootverbose)
                                printf("Linux arm64 ELF exec handler removed\n");
                } else
                        printf("Could not deinstall Linux arm64 ELF interpreter entry\n");
                break;
        default:
                return (EOPNOTSUPP);
        }
        return (error);
}

static moduledata_t linux64_elf_mod = {
        "linux64elf",
        linux64_elf_modevent,
        0
};

DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1);
FEATURE(linux64, "AArch64 Linux 64bit support");