1 files changed, 352 insertions, 0 deletions
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
new file mode 100644
index 000000000000..b780df513715
--- /dev/null
+++ b/tools/objtool/builtin-check.c
@@ -0,0 +1,352 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <subcmd/parse-options.h>
+#include <string.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/sendfile.h>
+#include <objtool/builtin.h>
+#include <objtool/objtool.h>
+#include <objtool/warn.h>
+
+#define ORIG_SUFFIX ".orig"
+
+int orig_argc;
+static char **orig_argv;
+const char *objname;
+struct opts opts;
+
+static const char * const check_usage[] = {
+	"objtool <actions> [<options>] file.o",
+	NULL,
+};
+
+static const char * const env_usage[] = {
+	"OBJTOOL_ARGS=\"<options>\"",
+	NULL,
+};
+
+static int parse_dump(const struct option *opt, const char *str, int unset)
+{
+	if (!str || !strcmp(str, "orc")) {
+		opts.dump_orc = true;
+		return 0;
+	}
+
+	return -1;
+}
+
+static int parse_hacks(const struct option *opt, const char *str, int unset)
+{
+	bool found = false;
+
+	/*
+	 * Use strstr() as a lazy method of checking for comma-separated
+	 * options.
+	 *
+	 * No string provided == enable all options.
+	 */
+
+	if (!str || strstr(str, "jump_label")) {
+		opts.hack_jump_label = true;
+		found = true;
+	}
+
+	if (!str || strstr(str, "noinstr")) {
+		opts.hack_noinstr = true;
+		found = true;
+	}
+
+	if (!str || strstr(str, "skylake")) {
+		opts.hack_skylake = true;
+		found = true;
+	}
+
+	return found ? 0 : -1;
+}
+
+static const struct option check_options[] = {
+	OPT_GROUP("Actions:"),
+	OPT_BOOLEAN(0,		 "checksum", &opts.checksum, "generate per-function checksums"),
+	OPT_BOOLEAN(0,		 "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
+	OPT_STRING_OPTARG('d',	 "disas", &opts.disas, "function-pattern", "disassemble functions", "*"),
+	OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
+	OPT_BOOLEAN('i',	 "ibt", &opts.ibt, "validate and annotate IBT"),
+	OPT_BOOLEAN('m',	 "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
+	OPT_BOOLEAN(0,		 "noabs", &opts.noabs, "reject absolute references in allocatable sections"),
+	OPT_BOOLEAN('n',	 "noinstr", &opts.noinstr, "validate noinstr rules"),
+	OPT_BOOLEAN(0,		 "orc", &opts.orc, "generate ORC metadata"),
+	OPT_BOOLEAN('r',	 "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
+	OPT_BOOLEAN(0,		 "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
+	OPT_BOOLEAN(0,		 "unret", &opts.unret, "validate entry unret placement"),
+	OPT_INTEGER(0,		 "prefix", &opts.prefix, "generate prefix symbols"),
+	OPT_BOOLEAN('l',	 "sls", &opts.sls, "validate straight-line-speculation mitigations"),
+	OPT_BOOLEAN('s',	 "stackval", &opts.stackval, "validate frame pointer rules"),
+	OPT_BOOLEAN('t',	 "static-call", &opts.static_call, "annotate static calls"),
+	OPT_BOOLEAN('u',	 "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
+	OPT_CALLBACK_OPTARG(0,	 "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
+
+	OPT_GROUP("Options:"),
+	OPT_BOOLEAN(0,		 "backtrace", &opts.backtrace, "unwind on error"),
+	OPT_BOOLEAN(0,		 "backup", &opts.backup, "create backup (.orig) file on warning/error"),
+	OPT_STRING(0,		 "debug-checksum", &opts.debug_checksum,  "funcs", "enable checksum debug output"),
+	OPT_BOOLEAN(0,		 "dry-run", &opts.dryrun, "don't write modifications"),
+	OPT_BOOLEAN(0,		 "link", &opts.link, "object is a linked object"),
+	OPT_BOOLEAN(0,		 "module", &opts.module, "object is part of a kernel module"),
+	OPT_BOOLEAN(0,		 "mnop", &opts.mnop, "nop out mcount call sites"),
+	OPT_BOOLEAN(0,		 "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
+	OPT_STRING('o',		 "output", &opts.output, "file", "output file name"),
+	OPT_BOOLEAN(0,		 "sec-address", &opts.sec_address, "print section addresses in warnings"),
+	OPT_BOOLEAN(0,		 "stats", &opts.stats, "print statistics"),
+	OPT_STRING(0,		 "trace", &opts.trace, "func", "trace function validation"),
+	OPT_BOOLEAN('v',	 "verbose", &opts.verbose, "verbose warnings"),
+	OPT_BOOLEAN(0,		 "werror", &opts.werror, "return error on warnings"),
+	OPT_BOOLEAN(0,		 "wide", &opts.wide, "wide output"),
+
+	OPT_END(),
+};
+
+int cmd_parse_options(int argc, const char **argv, const char * const usage[])
+{
+	const char *envv[16] = { };
+	char *env;
+	int envc;
+
+	env = getenv("OBJTOOL_ARGS");
+	if (env) {
+		envv[0] = "OBJTOOL_ARGS";
+		for (envc = 1; envc < ARRAY_SIZE(envv); ) {
+			envv[envc++] = env;
+			env = strchr(env, ' ');
+			if (!env)
+				break;
+			*env = '\0';
+			env++;
+		}
+
+		parse_options(envc, envv, check_options, env_usage, 0);
+	}
+
+	env = getenv("OBJTOOL_VERBOSE");
+	if (env && !strcmp(env, "1"))
+		opts.verbose = true;
+
+	argc = parse_options(argc, argv, check_options, usage, 0);
+	if (argc != 1)
+		usage_with_options(usage, check_options);
+	return argc;
+}
+
+static bool opts_valid(void)
+{
+	if (opts.mnop && !opts.mcount) {
+		ERROR("--mnop requires --mcount");
+		return false;
+	}
+
+	if (opts.noinstr && !opts.link) {
+		ERROR("--noinstr requires --link");
+		return false;
+	}
+
+	if (opts.ibt && !opts.link) {
+		ERROR("--ibt requires --link");
+		return false;
+	}
+
+	if (opts.unret && !opts.link) {
+		ERROR("--unret requires --link");
+		return false;
+	}
+
+#ifndef BUILD_KLP
+	if (opts.checksum) {
+		ERROR("--checksum not supported; install xxhash-devel/libxxhash-dev (version >= 0.8) and recompile");
+		return false;
+	}
+#endif
+
+	if (opts.debug_checksum && !opts.checksum) {
+		ERROR("--debug-checksum requires --checksum");
+		return false;
+	}
+
+	if (opts.checksum		||
+	    opts.disas			||
+	    opts.hack_jump_label	||
+	    opts.hack_noinstr		||
+	    opts.ibt			||
+	    opts.mcount			||
+	    opts.noabs			||
+	    opts.noinstr		||
+	    opts.orc			||
+	    opts.retpoline		||
+	    opts.rethunk		||
+	    opts.sls			||
+	    opts.stackval		||
+	    opts.static_call		||
+	    opts.uaccess) {
+		if (opts.dump_orc) {
+			ERROR("--dump can't be combined with other actions");
+			return false;
+		}
+
+		return true;
+	}
+
+	if (opts.dump_orc)
+		return true;
+
+	ERROR("At least one action required");
+	return false;
+}
+
+static int copy_file(const char *src, const char *dst)
+{
+	size_t to_copy, copied;
+	int dst_fd, src_fd;
+	struct stat stat;
+	off_t offset = 0;
+
+	src_fd = open(src, O_RDONLY);
+	if (src_fd == -1) {
+		ERROR("can't open %s for reading: %s", src, strerror(errno));
+		return 1;
+	}
+
+	dst_fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, 0400);
+	if (dst_fd == -1) {
+		ERROR("can't open %s for writing: %s", dst, strerror(errno));
+		return 1;
+	}
+
+	if (fstat(src_fd, &stat) == -1) {
+		ERROR_GLIBC("fstat");
+		return 1;
+	}
+
+	if (fchmod(dst_fd, stat.st_mode) == -1) {
+		ERROR_GLIBC("fchmod");
+		return 1;
+	}
+
+	for (to_copy = stat.st_size; to_copy > 0; to_copy -= copied) {
+		copied = sendfile(dst_fd, src_fd, &offset, to_copy);
+		if (copied == -1) {
+			ERROR_GLIBC("sendfile");
+			return 1;
+		}
+	}
+
+	close(dst_fd);
+	close(src_fd);
+	return 0;
+}
+
+static void save_argv(int argc, const char **argv)
+{
+	orig_argv = calloc(argc, sizeof(char *));
+	if (!orig_argv) {
+		ERROR_GLIBC("calloc");
+		exit(1);
+	}
+
+	for (int i = 0; i < argc; i++) {
+		orig_argv[i] = strdup(argv[i]);
+		if (!orig_argv[i]) {
+			ERROR_GLIBC("strdup(%s)", argv[i]);
+			exit(1);
+		}
+	}
+}
+
+int make_backup(void)
+{
+	char *backup;
+
+	/*
+	 * Make a backup before kbuild deletes the file so the error
+	 * can be recreated without recompiling or relinking.
+	 */
+	backup = malloc(strlen(objname) + strlen(ORIG_SUFFIX) + 1);
+	if (!backup) {
+		ERROR_GLIBC("malloc");
+		return 1;
+	}
+
+	strcpy(backup, objname);
+	strcat(backup, ORIG_SUFFIX);
+	if (copy_file(objname, backup))
+		return 1;
+
+	/*
+	 * Print the cmdline args to make it easier to recreate.
+	 */
+
+	fprintf(stderr, "%s", orig_argv[0]);
+
+	for (int i = 1; i < orig_argc; i++) {
+		char *arg = orig_argv[i];
+
+		/* Modify the printed args to use the backup */
+		if (!opts.output && !strcmp(arg, objname))
+			fprintf(stderr, " %s -o %s", backup, objname);
+		else
+			fprintf(stderr, " %s", arg);
+	}
+
+	fprintf(stderr, "\n");
+	return 0;
+}
+
+int objtool_run(int argc, const char **argv)
+{
+	struct objtool_file *file;
+	int ret = 0;
+
+	orig_argc = argc;
+	save_argv(argc, argv);
+
+	cmd_parse_options(argc, argv, check_usage);
+
+	if (!opts_valid())
+		return 1;
+
+	objname = argv[0];
+
+	if (opts.dump_orc)
+		return orc_dump(objname);
+
+	if (!opts.dryrun && opts.output) {
+		/* copy original .o file to output file */
+		if (copy_file(objname, opts.output))
+			return 1;
+
+		/* from here on, work directly on the output file */
+		objname = opts.output;
+	}
+
+	file = objtool_open_read(objname);
+	if (!file)
+		return 1;
+
+	if (!opts.link && has_multiple_files(file->elf)) {
+		ERROR("Linked object requires --link");
+		return 1;
+	}
+
+	ret = check(file);
+	if (ret)
+		return ret;
+
+	if (!opts.dryrun && file->elf->changed && elf_write(file->elf))
+		return 1;
+
+	return elf_close(file->elf);
+}