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objtool: Ditch subcommands 

Objtool has a fairly singular focus.  It runs on object files and does
validations and transformations which can be combined in various ways.
The subcommand model has never been a good fit, making it awkward to
combine and remove options.

Remove the "check" and "orc" subcommands in favor of a more traditional
cmdline option model.  This makes it much more flexible to use, and
easier to port individual features to other arches.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/5c61ebf805e90aefc5fa62bc63468ffae53b9df6.1650300597.git.jpoimboe@redhat.com
This commit is contained in:
Josh Poimboeuf 2022-04-18 09:50:27 -07:00 committed by Peter Zijlstra
parent 2daf7faba7
commit b51277eb97
10 changed files with 72 additions and 211 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
scripts/Makefile.build
View File

@ -227,9 +227,9 @@ ifdef CONFIG_STACK_VALIDATION
objtool := $(objtree)/tools/objtool/objtool
objtool_args = \
$(if $(CONFIG_UNWINDER_ORC),orc generate,check) \
$(if $(CONFIG_X86_KERNEL_IBT), --lto --ibt) \
$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
$(if $(CONFIG_UNWINDER_ORC), --orc) \
$(if $(CONFIG_RETPOLINE), --retpoline) \
$(if $(CONFIG_SLS), --sls) \
$(if $(CONFIG_X86_SMAP), --uaccess) \

13
scripts/link-vmlinux.sh
View File

@ -113,9 +113,6 @@ objtool_link()
# Don't perform vmlinux validation unless explicitly requested,
# but run objtool on vmlinux.o now that we have an object file.
if is_enabled CONFIG_UNWINDER_ORC; then
objtoolcmd="orc generate"
fi
if is_enabled CONFIG_X86_KERNEL_IBT; then
objtoolopt="${objtoolopt} --ibt"
@ -125,6 +122,10 @@ objtool_link()
objtoolopt="${objtoolopt} --mcount"
fi
if is_enabled CONFIG_UNWINDER_ORC; then
objtoolopt="${objtoolopt} --orc"
fi
objtoolopt="${objtoolopt} --lto"
fi
@ -134,10 +135,6 @@ objtool_link()
if [ -n "${objtoolopt}" ]; then
if [ -z "${objtoolcmd}" ]; then
objtoolcmd="check"
fi
if is_enabled CONFIG_RETPOLINE; then
objtoolopt="${objtoolopt} --retpoline"
fi
@ -161,7 +158,7 @@ objtool_link()
objtoolopt="${objtoolopt} --vmlinux"
info OBJTOOL ${1}
tools/objtool/objtool ${objtoolcmd} ${objtoolopt} ${1}
tools/objtool/objtool ${objtoolopt} ${1}
fi
}

12
tools/objtool/Build
View File

@ -2,17 +2,15 @@ objtool-y += arch/$(SRCARCH)/
objtool-y += weak.o
objtool-$(SUBCMD_CHECK) += check.o
objtool-$(SUBCMD_CHECK) += special.o
objtool-$(SUBCMD_ORC) += check.o
objtool-$(SUBCMD_ORC) += orc_gen.o
objtool-$(SUBCMD_ORC) += orc_dump.o
objtool-y += check.o
objtool-y += special.o
objtool-y += builtin-check.o
objtool-y += builtin-orc.o
objtool-y += elf.o
objtool-y += objtool.o
objtool-$(BUILD_ORC) += orc_gen.o
objtool-$(BUILD_ORC) += orc_dump.o
objtool-y += libstring.o
objtool-y += libctype.o
objtool-y += str_error_r.o

8
tools/objtool/Makefile
View File

@ -39,15 +39,13 @@ CFLAGS += $(if $(elfshdr),,-DLIBELF_USE_DEPRECATED)
AWK = awk
SUBCMD_CHECK := n
SUBCMD_ORC := n
BUILD_ORC := n
ifeq ($(SRCARCH),x86)
SUBCMD_CHECK := y
SUBCMD_ORC := y
BUILD_ORC := y
endif
export SUBCMD_CHECK SUBCMD_ORC
export BUILD_ORC
export srctree OUTPUT CFLAGS SRCARCH AWK
include $(srctree)/tools/build/Makefile.include

56
tools/objtool/builtin-check.c
View File

@ -3,16 +3,6 @@
* 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>
@ -22,7 +12,7 @@
struct opts opts;
static const char * const check_usage[] = {
"objtool check <actions> [<options>] file.o",
"objtool <actions> [<options>] file.o",
NULL,
};
@ -31,14 +21,26 @@ static const char * const env_usage[] = {
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;
}
const struct option check_options[] = {
OPT_GROUP("Actions:"),
OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
OPT_BOOLEAN('o', "orc", &opts.orc, "generate ORC metadata"),
OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
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"),
@ -81,7 +83,31 @@ int cmd_parse_options(int argc, const char **argv, const char * const usage[])
return argc;
}
int cmd_check(int argc, const char **argv)
static bool opts_valid(void)
{
if (opts.ibt ||
opts.mcount ||
opts.noinstr ||
opts.orc ||
opts.retpoline ||
opts.sls ||
opts.uaccess) {
if (opts.dump_orc) {
fprintf(stderr, "--dump can't be combined with other options\n");
return false;
}
return true;
}
if (opts.dump_orc)
return true;
fprintf(stderr, "At least one command required\n");
return false;
}
int objtool_run(int argc, const char **argv)
{
const char *objname;
struct objtool_file *file;
@ -90,6 +116,12 @@ int cmd_check(int argc, const char **argv)
argc = cmd_parse_options(argc, argv, check_usage);
objname = argv[0];
if (!opts_valid())
return 1;
if (opts.dump_orc)
return orc_dump(objname);
file = objtool_open_read(objname);
if (!file)
return 1;

73
tools/objtool/builtin-orc.c
View File

@ -1,73 +0,0 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
/*
* objtool orc:
*
* This command analyzes a .o file and adds .orc_unwind and .orc_unwind_ip
* sections to it, which is used by the in-kernel ORC unwinder.
*
* This command is a superset of "objtool check".
*/
#include <string.h>
#include <objtool/builtin.h>
#include <objtool/objtool.h>
static const char *orc_usage[] = {
"objtool orc generate [<options>] file.o",
"objtool orc dump file.o",
NULL,
};
int cmd_orc(int argc, const char **argv)
{
const char *objname;
argc--; argv++;
if (argc <= 0)
usage_with_options(orc_usage, check_options);
if (!strncmp(argv[0], "gen", 3)) {
struct objtool_file *file;
int ret;
argc = cmd_parse_options(argc, argv, orc_usage);
objname = argv[0];
file = objtool_open_read(objname);
if (!file)
return 1;
ret = check(file);
if (ret)
return ret;
if (list_empty(&file->insn_list))
return 0;
ret = orc_create(file);
if (ret)
return ret;
if (!file->elf->changed)
return 0;
return elf_write(file->elf);
}
if (!strcmp(argv[0], "dump")) {
if (argc != 2)
usage_with_options(orc_usage, check_options);
objname = argv[1];
return orc_dump(objname);
}
usage_with_options(orc_usage, check_options);
return 0;
}

8
tools/objtool/check.c
View File

@ -3949,6 +3949,14 @@ int check(struct objtool_file *file)
warnings += ret;
}
if (opts.orc && !list_empty(&file->insn_list)) {
ret = orc_create(file);
if (ret < 0)
goto out;
warnings += ret;
}
if (opts.stats) {
printf("nr_insns_visited: %ld\n", nr_insns_visited);
printf("nr_cfi: %ld\n", nr_cfi);

5
tools/objtool/include/objtool/builtin.h
View File

@ -11,9 +11,11 @@ extern const struct option check_options[];
struct opts {
/* actions: */
bool dump_orc;
bool ibt;
bool mcount;
bool noinstr;
bool orc;
bool retpoline;
bool sls;
bool uaccess;
@ -34,7 +36,6 @@ extern struct opts opts;
extern int cmd_parse_options(int argc, const char **argv, const char * const usage[]);
extern int cmd_check(int argc, const char **argv);
extern int cmd_orc(int argc, const char **argv);
extern int objtool_run(int argc, const char **argv);
#endif /* _BUILTIN_H */

97
tools/objtool/objtool.c
View File

@ -3,16 +3,6 @@
* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
*/
/*
* objtool:
*
* The 'check' subcmd 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 <stdio.h>
#include <stdbool.h>
#include <string.h>
@ -26,20 +16,6 @@
#include <objtool/objtool.h>
#include <objtool/warn.h>
struct cmd_struct {
const char *name;
int (*fn)(int, const char **);
const char *help;
};
static const char objtool_usage_string[] =
"objtool COMMAND [ARGS]";
static struct cmd_struct objtool_cmds[] = {
{"check", cmd_check, "Perform stack metadata validation on an object file" },
{"orc", cmd_orc, "Generate in-place ORC unwind tables for an object file" },
};
bool help;
const char *objname;
@ -161,70 +137,6 @@ void objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
f->pv_ops[idx].clean = false;
}
static void cmd_usage(void)
{
unsigned int i, longest = 0;
printf("\n usage: %s\n\n", objtool_usage_string);
for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
if (longest < strlen(objtool_cmds[i].name))
longest = strlen(objtool_cmds[i].name);
}
puts(" Commands:");
for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
printf(" %-*s ", longest, objtool_cmds[i].name);
puts(objtool_cmds[i].help);
}
printf("\n");
if (!help)
exit(129);
exit(0);
}
static void handle_options(int *argc, const char ***argv)
{
while (*argc > 0) {
const char *cmd = (*argv)[0];
if (cmd[0] != '-')
break;
if (!strcmp(cmd, "--help") || !strcmp(cmd, "-h")) {
help = true;
break;
} else {
fprintf(stderr, "Unknown option: %s\n", cmd);
cmd_usage();
}
(*argv)++;
(*argc)--;
}
}
static void handle_internal_command(int argc, const char **argv)
{
const char *cmd = argv[0];
unsigned int i, ret;
for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
struct cmd_struct *p = objtool_cmds+i;
if (strcmp(p->name, cmd))
continue;
ret = p->fn(argc, argv);
exit(ret);
}
cmd_usage();
}
int main(int argc, const char **argv)
{
static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
@ -233,14 +145,7 @@ int main(int argc, const char **argv)
exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
pager_init(UNUSED);
argv++;
argc--;
handle_options(&argc, &argv);
if (!argc || help)
cmd_usage();
handle_internal_command(argc, argv);
objtool_run(argc, argv);
return 0;
}

9
tools/objtool/weak.c
View File

@ -15,17 +15,12 @@
return ENOSYS; \
})
int __weak check(struct objtool_file *file)
{
UNSUPPORTED("check subcommand");
}
int __weak orc_dump(const char *_objname)
{
UNSUPPORTED("orc");
UNSUPPORTED("ORC");
}
int __weak orc_create(struct objtool_file *file)
{
UNSUPPORTED("orc");
UNSUPPORTED("ORC");
}