1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
 4 */
 5
 6/*
 7 * objtool check:
 8 *
 9 * This command analyzes every .o file and ensures the validity of its stack
10 * trace metadata.  It enforces a set of rules on asm code and C inline
11 * assembly code so that stack traces can be reliable.
12 *
13 * For more information, see tools/objtool/Documentation/stack-validation.txt.
14 */
15
16#include <subcmd/parse-options.h>
17#include <string.h>
18#include <stdlib.h>
19#include <objtool/builtin.h>
20#include <objtool/objtool.h>
21
22bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats,
23     validate_dup, vmlinux, mcount, noinstr, backup;
24
25static const char * const check_usage[] = {
26	"objtool check [<options>] file.o",
27	NULL,
28};
29
30static const char * const env_usage[] = {
31	"OBJTOOL_ARGS=\"<options>\"",
32	NULL,
33};
34
35const struct option check_options[] = {
36	OPT_BOOLEAN('f', "no-fp", &no_fp, "Skip frame pointer validation"),
37	OPT_BOOLEAN('u', "no-unreachable", &no_unreachable, "Skip 'unreachable instruction' warnings"),
38	OPT_BOOLEAN('r', "retpoline", &retpoline, "Validate retpoline assumptions"),
39	OPT_BOOLEAN('m', "module", &module, "Indicates the object will be part of a kernel module"),
40	OPT_BOOLEAN('b', "backtrace", &backtrace, "unwind on error"),
41	OPT_BOOLEAN('a', "uaccess", &uaccess, "enable uaccess checking"),
42	OPT_BOOLEAN('s', "stats", &stats, "print statistics"),
43	OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"),
44	OPT_BOOLEAN('n', "noinstr", &noinstr, "noinstr validation for vmlinux.o"),
45	OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"),
46	OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"),
47	OPT_BOOLEAN('B', "backup", &backup, "create .orig files before modification"),
48	OPT_END(),
49};
50
51int cmd_parse_options(int argc, const char **argv, const char * const usage[])
52{
53	const char *envv[16] = { };
54	char *env;
55	int envc;
56
57	env = getenv("OBJTOOL_ARGS");
58	if (env) {
59		envv[0] = "OBJTOOL_ARGS";
60		for (envc = 1; envc < ARRAY_SIZE(envv); ) {
61			envv[envc++] = env;
62			env = strchr(env, ' ');
63			if (!env)
64				break;
65			*env = '\0';
66			env++;
67		}
68
69		parse_options(envc, envv, check_options, env_usage, 0);
70	}
71
72	argc = parse_options(argc, argv, check_options, usage, 0);
73	if (argc != 1)
74		usage_with_options(usage, check_options);
75	return argc;
76}
77
78int cmd_check(int argc, const char **argv)
79{
80	const char *objname;
81	struct objtool_file *file;
82	int ret;
83
84	argc = cmd_parse_options(argc, argv, check_usage);
85	objname = argv[0];
86
87	file = objtool_open_read(objname);
88	if (!file)
89		return 1;
90
91	ret = check(file);
92	if (ret)
93		return ret;
94
95	if (file->elf->changed)
96		return elf_write(file->elf);
97
98	return 0;
99}