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@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 */
64int
65ELFNAME2(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