tools/objtool/builtin-check.c

   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
  17 struct opts opts;
  18
  19 static const char * const check_usage[] = {
  20         "objtool <actions> [<options>] file.o",
  21         NULL,
  22 };
  23
  24 static const char * const env_usage[] = {
  25         "OBJTOOL_ARGS=\"<options>\"",
  26         NULL,
  27 };
  28
  29 static 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
  39 static 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
  68 static 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
 101 int 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
 132 static 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 actions");
 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 action required");
 163         return false;
 164 }
 165
 166 static 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
 176 static 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
 205 int 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 }