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      1 /* $NetBSD: linux_exec_powerpc.c,v 1.25 2021/09/07 11:43:04 riastradh Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Emmanuel Dreyfus.
      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 /*
     33  * From NetBSD's sys/compat/arch/alpha/linux_exec_alpha.c, with some
     34  * powerpc add-ons (ifdef LINUX_SHIFT).
     35  *
     36  * This code is to be common to alpha and powerpc. If it works on alpha, it
     37  * should be moved to common/linux_exec_elf32.c. Beware that it needs
     38  * LINUX_ELF_AUX_ENTRIES in arch/<arch>/linux_exec.h to also be moved to common
     39  *
     40  * Emmanuel Dreyfus <p99dreyf (at) criens.u-psud.fr>
     41  */
     42 
     43 #include <sys/cdefs.h>
     44 __KERNEL_RCSID(0, "$NetBSD: linux_exec_powerpc.c,v 1.25 2021/09/07 11:43:04 riastradh Exp $");
     45 
     46 #define ELFSIZE 32
     47 
     48 #include <sys/param.h>
     49 #include <sys/systm.h>
     50 #include <sys/kernel.h>
     51 #include <sys/proc.h>
     52 #include <sys/exec.h>
     53 #include <sys/exec_elf.h>
     54 #include <sys/resourcevar.h>
     55 #include <sys/kauth.h>
     56 
     57 #include <uvm/uvm_extern.h>
     58 
     59 #include <compat/linux/common/linux_exec.h>
     60 
     61 /*
     62  * Alpha and PowerPC specific linux copyargs function.
     63  */
     64 int
     65 ELFNAME2(linux,copyargs)(struct lwp *l, struct exec_package *pack,
     66 			 struct ps_strings *arginfo, char **stackp,
     67 			 void *argp)
     68 {
     69 	size_t len;
     70 	AuxInfo ai[LINUX_ELF_AUX_ENTRIES], *a;
     71 	struct elf_args *ap;
     72 	int error;
     73 
     74 #ifdef LINUX_SHIFT
     75 	/*
     76 	 * Seems that PowerPC Linux binaries expect argc to start on a 16 bytes
     77 	 * aligned address. And we need one more 16 byte shift if it was already
     78 	 * 16 bytes aligned,
     79 	 */
     80 	*stackp = (char *)(((unsigned long)*stackp - 1) & ~LINUX_SHIFT);
     81 #endif
     82 
     83 	if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0)
     84 		return error;
     85 
     86 #ifdef LINUX_SHIFT
     87 	/*
     88 	 * From Linux's arch/ppc/kernel/process.c:shove_aux_table(). GNU ld.so
     89 	 * expects the ELF auxiliary table to start on a 16 bytes boundary on
     90 	 * the PowerPC.
     91 	 */
     92 	*stackp = (char *)(((unsigned long)(*stackp) + LINUX_SHIFT)
     93 	    & ~LINUX_SHIFT);
     94 #endif
     95 
     96 	memset(ai, 0, sizeof(ai));
     97 
     98 	a = ai;
     99 
    100 	/*
    101 	 * Push extra arguments on the stack needed by dynamically
    102 	 * linked binaries.
    103 	 */
    104 	if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
    105 #if 1
    106 		/*
    107 		 * The exec_package doesn't have a proc pointer and it's not
    108 		 * exactly trivial to add one since the credentials are
    109 		 * changing. XXX Linux uses curlwp's credentials.
    110 		 * Why can't we use them too? XXXad we do, what's different?
    111 		 */
    112 		a->a_type = LINUX_AT_EGID;
    113 		a->a_v = kauth_cred_getegid(l->l_cred);
    114 		a++;
    115 
    116 		a->a_type = LINUX_AT_GID;
    117 		a->a_v = kauth_cred_getgid(l->l_cred);
    118 		a++;
    119 
    120 		a->a_type = LINUX_AT_EUID;
    121 		a->a_v = kauth_cred_geteuid(l->l_cred);
    122 		a++;
    123 
    124 		a->a_type = LINUX_AT_UID;
    125 		a->a_v = kauth_cred_getuid(l->l_cred);
    126 		a++;
    127 #endif
    128 
    129 		a->a_type = AT_ENTRY;
    130 		a->a_v = ap->arg_entry;
    131 		a++;
    132 
    133 		a->a_type = AT_FLAGS;
    134 		a->a_v = 0;
    135 		a++;
    136 
    137 		a->a_type = AT_BASE;
    138 		a->a_v = ap->arg_interp;
    139 		a++;
    140 
    141 		a->a_type = AT_PHNUM;
    142 		a->a_v = ap->arg_phnum;
    143 		a++;
    144 
    145 		a->a_type = AT_PHENT;
    146 		a->a_v = ap->arg_phentsize;
    147 		a++;
    148 
    149 		a->a_type = AT_PHDR;
    150 		a->a_v = ap->arg_phaddr;
    151 		a++;
    152 
    153 		a->a_type = LINUX_AT_CLKTCK;
    154 		a->a_v = LINUX_CLOCKS_PER_SEC;
    155 		a++;
    156 
    157 		a->a_type = AT_PAGESZ;
    158 		a->a_v = PAGE_SIZE;
    159 		a++;
    160 
    161 		a->a_type = LINUX_AT_HWCAP;
    162 		a->a_v = LINUX_ELF_HWCAP;
    163 		a++;
    164 
    165 		exec_free_emul_arg(pack);
    166 	}
    167 
    168 	a->a_type = AT_NULL;
    169 	a->a_v = 0;
    170 	a++;
    171 
    172 	len = (a - ai) * sizeof(AuxInfo);
    173 
    174 	if ((error = copyout(ai, *stackp, len)) != 0)
    175 		return error;
    176 	*stackp += len;
    177 	return 0;
    178 }
    179