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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Miroslav Benes <[email protected]>
Link: https://lkml.kernel.org/r/5c61ebf805e90aefc5fa62bc63468ffae53b9df6.1650300597.git.jpoimboe@redhat.com

Author: jpoimboe

scripts/Makefile.build

@@ -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)				\

scripts/link-vmlinux.sh

@@ -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
 }
 

tools/objtool/Build

@@ -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

tools/objtool/Makefile

@@ -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
 

tools/objtool/builtin-check.c

@@ -3,16 +3,6 @@
  * Copyright (C) 2015-2017 Josh Poimboeuf <[email protected]>
  */
 
-/*
- * 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;

tools/objtool/builtin-orc.c

@@ -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);

tools/objtool/check.c

@@ -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 */