1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
4 */
5
6#include <subcmd/parse-options.h>
7#include <string.h>
8#include <stdlib.h>
9#include <objtool/builtin.h>
10#include <objtool/objtool.h>
11
12#define ERROR(format, ...)				\
13	fprintf(stderr,					\
14		"error: objtool: " format "\n",		\
15		##__VA_ARGS__)
16
17struct opts opts;
18
19static const char * const check_usage[] = {
20	"objtool <actions> [<options>] file.o",
21	NULL,
22};
23
24static const char * const env_usage[] = {
25	"OBJTOOL_ARGS=\"<options>\"",
26	NULL,
27};
28
29static int parse_dump(const struct option *opt, const char *str, int unset)
30{
31	if (!str || !strcmp(str, "orc")) {
32		opts.dump_orc = true;
33		return 0;
34	}
35
36	return -1;
37}
38
39static int parse_hacks(const struct option *opt, const char *str, int unset)
40{
41	bool found = false;
42
43	/*
44	 * Use strstr() as a lazy method of checking for comma-separated
45	 * options.
46	 *
47	 * No string provided == enable all options.
48	 */
49
50	if (!str || strstr(str, "jump_label")) {
51		opts.hack_jump_label = true;
52		found = true;
53	}
54
55	if (!str || strstr(str, "noinstr")) {
56		opts.hack_noinstr = true;
57		found = true;
58	}
59
60	if (!str || strstr(str, "skylake")) {
61		opts.hack_skylake = true;
62		found = true;
63	}
64
65	return found ? 0 : -1;
66}
67
68static const struct option check_options[] = {
69	OPT_GROUP("Actions:"),
70	OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
71	OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
72	OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
73	OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
74	OPT_BOOLEAN('o', "orc", &opts.orc, "generate ORC metadata"),
75	OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
76	OPT_BOOLEAN(0,   "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
77	OPT_BOOLEAN(0,   "unret", &opts.unret, "validate entry unret placement"),
78	OPT_INTEGER(0,   "prefix", &opts.prefix, "generate prefix symbols"),
79	OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
80	OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
81	OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
82	OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
83	OPT_BOOLEAN(0  , "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
84	OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
85
86	OPT_GROUP("Options:"),
87	OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
88	OPT_BOOLEAN(0, "backup", &opts.backup, "create .orig files before modification"),
89	OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
90	OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
91	OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
92	OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
93	OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
94	OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
95	OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
96	OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
97
98	OPT_END(),
99};
100
101int cmd_parse_options(int argc, const char **argv, const char * const usage[])
102{
103	const char *envv[16] = { };
104	char *env;
105	int envc;
106
107	env = getenv("OBJTOOL_ARGS");
108	if (env) {
109		envv[0] = "OBJTOOL_ARGS";
110		for (envc = 1; envc < ARRAY_SIZE(envv); ) {
111			envv[envc++] = env;
112			env = strchr(env, ' ');
113			if (!env)
114				break;
115			*env = '\0';
116			env++;
117		}
118
119		parse_options(envc, envv, check_options, env_usage, 0);
120	}
121
122	env = getenv("OBJTOOL_VERBOSE");
123	if (env && !strcmp(env, "1"))
124		opts.verbose = true;
125
126	argc = parse_options(argc, argv, check_options, usage, 0);
127	if (argc != 1)
128		usage_with_options(usage, check_options);
129	return argc;
130}
131
132static bool opts_valid(void)
133{
134	if (opts.hack_jump_label	||
135	    opts.hack_noinstr		||
136	    opts.ibt			||
137	    opts.mcount			||
138	    opts.noinstr		||
139	    opts.orc			||
140	    opts.retpoline		||
141	    opts.rethunk		||
142	    opts.sls			||
143	    opts.stackval		||
144	    opts.static_call		||
145	    opts.uaccess) {
146		if (opts.dump_orc) {
147			ERROR("--dump can't be combined with other options");
148			return false;
149		}
150
151		return true;
152	}
153
154	if (opts.unret && !opts.rethunk) {
155		ERROR("--unret requires --rethunk");
156		return false;
157	}
158
159	if (opts.dump_orc)
160		return true;
161
162	ERROR("At least one command required");
163	return false;
164}
165
166static bool mnop_opts_valid(void)
167{
168	if (opts.mnop && !opts.mcount) {
169		ERROR("--mnop requires --mcount");
170		return false;
171	}
172
173	return true;
174}
175
176static bool link_opts_valid(struct objtool_file *file)
177{
178	if (opts.link)
179		return true;
180
181	if (has_multiple_files(file->elf)) {
182		ERROR("Linked object detected, forcing --link");
183		opts.link = true;
184		return true;
185	}
186
187	if (opts.noinstr) {
188		ERROR("--noinstr requires --link");
189		return false;
190	}
191
192	if (opts.ibt) {
193		ERROR("--ibt requires --link");
194		return false;
195	}
196
197	if (opts.unret) {
198		ERROR("--unret requires --link");
199		return false;
200	}
201
202	return true;
203}
204
205int objtool_run(int argc, const char **argv)
206{
207	const char *objname;
208	struct objtool_file *file;
209	int ret;
210
211	argc = cmd_parse_options(argc, argv, check_usage);
212	objname = argv[0];
213
214	if (!opts_valid())
215		return 1;
216
217	if (opts.dump_orc)
218		return orc_dump(objname);
219
220	file = objtool_open_read(objname);
221	if (!file)
222		return 1;
223
224	if (!mnop_opts_valid())
225		return 1;
226
227	if (!link_opts_valid(file))
228		return 1;
229
230	ret = check(file);
231	if (ret)
232		return ret;
233
234	if (file->elf->changed)
235		return elf_write(file->elf);
236
237	return 0;
238}
239