linux/tools/objtool/builtin-check.c
Peter Zijlstra 08f87a93c8 objtool: Validate IBT assumptions
Intel IBT requires that every indirect JMP/CALL targets an ENDBR
instructions, failing this #CP happens and we die. Similarly, all
exception entries should be ENDBR.

Find all code relocations and ensure they're either an ENDBR
instruction or ANNOTATE_NOENDBR. For the exceptions look for
UNWIND_HINT_IRET_REGS at sym+0 not being ENDBR.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.705110141@infradead.org
2022-03-15 10:32:46 +01:00

104 lines
2.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
/*
* objtool check:
*
* This command analyzes every .o file and ensures the validity of its stack
* trace metadata. It enforces a set of rules on asm code and C inline
* assembly code so that stack traces can be reliable.
*
* For more information, see tools/objtool/Documentation/stack-validation.txt.
*/
#include <subcmd/parse-options.h>
#include <string.h>
#include <stdlib.h>
#include <objtool/builtin.h>
#include <objtool/objtool.h>
bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats,
lto, vmlinux, mcount, noinstr, backup, sls, dryrun,
ibt;
static const char * const check_usage[] = {
"objtool check [<options>] file.o",
NULL,
};
static const char * const env_usage[] = {
"OBJTOOL_ARGS=\"<options>\"",
NULL,
};
const struct option check_options[] = {
OPT_BOOLEAN('f', "no-fp", &no_fp, "Skip frame pointer validation"),
OPT_BOOLEAN('u', "no-unreachable", &no_unreachable, "Skip 'unreachable instruction' warnings"),
OPT_BOOLEAN('r', "retpoline", &retpoline, "Validate retpoline assumptions"),
OPT_BOOLEAN('m', "module", &module, "Indicates the object will be part of a kernel module"),
OPT_BOOLEAN('b', "backtrace", &backtrace, "unwind on error"),
OPT_BOOLEAN('a', "uaccess", &uaccess, "enable uaccess checking"),
OPT_BOOLEAN('s', "stats", &stats, "print statistics"),
OPT_BOOLEAN(0, "lto", &lto, "whole-archive like runs"),
OPT_BOOLEAN('n', "noinstr", &noinstr, "noinstr validation for vmlinux.o"),
OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"),
OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"),
OPT_BOOLEAN('B', "backup", &backup, "create .orig files before modification"),
OPT_BOOLEAN('S', "sls", &sls, "validate straight-line-speculation"),
OPT_BOOLEAN(0, "dry-run", &dryrun, "don't write the modifications"),
OPT_BOOLEAN(0, "ibt", &ibt, "validate ENDBR placement"),
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);
}
argc = parse_options(argc, argv, check_options, usage, 0);
if (argc != 1)
usage_with_options(usage, check_options);
return argc;
}
int cmd_check(int argc, const char **argv)
{
const char *objname;
struct objtool_file *file;
int ret;
argc = cmd_parse_options(argc, argv, check_usage);
objname = argv[0];
file = objtool_open_read(objname);
if (!file)
return 1;
ret = check(file);
if (ret)
return ret;
if (file->elf->changed)
return elf_write(file->elf);
return 0;
}