/*      $NetBSD: cpu_exec.c,v 1.13 2020/12/01 02:43:13 rin Exp $        */

/*-
 * Copyright (c) 2012 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cpu_exec.c,v 1.13 2020/12/01 02:43:13 rin Exp $");

#include "opt_compat_netbsd.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/exec.h>

#include <uvm/uvm_extern.h>

#include <compat/common/compat_util.h>
#include <sys/exec_elf.h>                       /* mandatory */

#include <arm/locore.h>

#if EXEC_ELF32
int
arm_netbsd_elf32_probe(struct lwp *l, struct exec_package *epp, void *eh0,
        char *itp, vaddr_t *start_p)
{
        const char *itp_suffix = NULL;
        const Elf_Ehdr * const eh = eh0;
        const bool elf_aapcs_p =
            (eh->e_flags & EF_ARM_EABIMASK) >= EF_ARM_EABI_VER4;
#if defined(COMPAT_NETBSD32) || defined(MODULAR)
        const bool netbsd32_p = (epp->ep_esch->es_emul != &emul_netbsd);
#else
        const bool netbsd32_p = false;
#endif
#ifdef __ARM_EABI__
        const bool aapcs_p = true;
#else
        const bool aapcs_p = false;
#endif
#ifdef __ARMEB__
        const bool be8_p = (eh->e_flags & EF_ARM_BE8) != 0;

        /*
         * If the BE-8 model is supported, CPSR[7] will be clear.
         * If the BE-32 model is supported, CPSR[7] will be set.
         */
#ifdef _ARM_ARCH_BE8
        if (!be8_p)
#else
        if (be8_p)
#endif
                return ENOEXEC;
#endif /* __ARMEB__ */

        /*
         * This is subtle.  If we are netbsd32, then we don't want to match the
         * same ABI as the kernel.  If we aren't (netbsd32 == false), then we
         * don't want to be different from the kernel's ABI.
         *    true   true   true  ENOEXEC
         *    true   false  true  0
         *    true   true   false 0
         *    true   false  false ENOEXEC
         *    false  true   true  0
         *    false  false  true  ENOEXEC
         *    false  true   false ENOEXEC
         *    false  false  false 0
         */
        if (netbsd32_p ^ elf_aapcs_p ^ aapcs_p)
                return ENOEXEC;

        if (netbsd32_p)
                itp_suffix = (elf_aapcs_p) ? "eabi" : "oabi";

        if (itp_suffix != NULL)
                (void)compat_elf_check_interp(epp, itp, itp_suffix);

        /*
         * Copy (if any) the machine_arch of the executable to the proc.
         */
        if (epp->ep_machine_arch[0] != 0) {
                strlcpy(l->l_proc->p_md.md_march, epp->ep_machine_arch,
                    sizeof(l->l_proc->p_md.md_march));
        }

        /*
         * If we are AAPCS (EABI) and armv6/armv7, we want alignment faults
         * to be off.
         */
#if defined(__ARMEL__)
        if (aapcs_p && (CPU_IS_ARMV7_P() || CPU_IS_ARMV6_P()))
#elif defined(_ARM_ARCH_BE8)
        if (aapcs_p)
#else
        if (false /* CONSTCOND */)
#endif
        {
                l->l_md.md_flags |= MDLWP_NOALIGNFLT;
        } else {
                l->l_md.md_flags &= ~MDLWP_NOALIGNFLT;
        }
        return 0;
}
#endif