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      1 /*	$NetBSD: cpu_exec.c,v 1.13 2020/12/01 02:43:13 rin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2012 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Matt Thomas of 3am Software Foundry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: cpu_exec.c,v 1.13 2020/12/01 02:43:13 rin Exp $");
     34 
     35 #include "opt_compat_netbsd.h"
     36 
     37 #include <sys/param.h>
     38 #include <sys/systm.h>
     39 #include <sys/proc.h>
     40 #include <sys/exec.h>
     41 
     42 #include <uvm/uvm_extern.h>
     43 
     44 #include <compat/common/compat_util.h>
     45 #include <sys/exec_elf.h>			/* mandatory */
     46 
     47 #include <arm/locore.h>
     48 
     49 #if EXEC_ELF32
     50 int
     51 arm_netbsd_elf32_probe(struct lwp *l, struct exec_package *epp, void *eh0,
     52 	char *itp, vaddr_t *start_p)
     53 {
     54 	const char *itp_suffix = NULL;
     55 	const Elf_Ehdr * const eh = eh0;
     56 	const bool elf_aapcs_p =
     57 	    (eh->e_flags & EF_ARM_EABIMASK) >= EF_ARM_EABI_VER4;
     58 #if defined(COMPAT_NETBSD32) || defined(MODULAR)
     59 	const bool netbsd32_p = (epp->ep_esch->es_emul != &emul_netbsd);
     60 #else
     61 	const bool netbsd32_p = false;
     62 #endif
     63 #ifdef __ARM_EABI__
     64 	const bool aapcs_p = true;
     65 #else
     66 	const bool aapcs_p = false;
     67 #endif
     68 #ifdef __ARMEB__
     69 	const bool be8_p = (eh->e_flags & EF_ARM_BE8) != 0;
     70 
     71 	/*
     72 	 * If the BE-8 model is supported, CPSR[7] will be clear.
     73 	 * If the BE-32 model is supported, CPSR[7] will be set.
     74 	 */
     75 #ifdef _ARM_ARCH_BE8
     76 	if (!be8_p)
     77 #else
     78 	if (be8_p)
     79 #endif
     80 		return ENOEXEC;
     81 #endif /* __ARMEB__ */
     82 
     83 	/*
     84 	 * This is subtle.  If we are netbsd32, then we don't want to match the
     85 	 * same ABI as the kernel.  If we aren't (netbsd32 == false), then we
     86 	 * don't want to be different from the kernel's ABI.
     87 	 *    true   true   true  ENOEXEC
     88 	 *    true   false  true  0
     89 	 *    true   true   false 0
     90 	 *    true   false  false ENOEXEC
     91 	 *    false  true   true  0
     92 	 *    false  false  true  ENOEXEC
     93 	 *    false  true   false ENOEXEC
     94 	 *    false  false  false 0
     95 	 */
     96 	if (netbsd32_p ^ elf_aapcs_p ^ aapcs_p)
     97 		return ENOEXEC;
     98 
     99 	if (netbsd32_p)
    100 		itp_suffix = (elf_aapcs_p) ? "eabi" : "oabi";
    101 
    102 	if (itp_suffix != NULL)
    103 		(void)compat_elf_check_interp(epp, itp, itp_suffix);
    104 
    105 	/*
    106 	 * Copy (if any) the machine_arch of the executable to the proc.
    107 	 */
    108 	if (epp->ep_machine_arch[0] != 0) {
    109 		strlcpy(l->l_proc->p_md.md_march, epp->ep_machine_arch,
    110 		    sizeof(l->l_proc->p_md.md_march));
    111 	}
    112 
    113 	/*
    114 	 * If we are AAPCS (EABI) and armv6/armv7, we want alignment faults
    115 	 * to be off.
    116 	 */
    117 #if defined(__ARMEL__)
    118 	if (aapcs_p && (CPU_IS_ARMV7_P() || CPU_IS_ARMV6_P()))
    119 #elif defined(_ARM_ARCH_BE8)
    120 	if (aapcs_p)
    121 #else
    122 	if (false /* CONSTCOND */)
    123 #endif
    124 	{
    125 		l->l_md.md_flags |= MDLWP_NOALIGNFLT;
    126 	} else {
    127 		l->l_md.md_flags &= ~MDLWP_NOALIGNFLT;
    128 	}
    129 	return 0;
    130 }
    131 #endif
    132