[PATCH v6 10/25] objtool: Split noinstr validation from --vmlinux

From: Sami Tolvanen <samitolvanen@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	clang-built-linux@googlegroups.com,
	kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-pci@vger.kernel.org, x86@kernel.org,
	Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH v6 10/25] objtool: Split noinstr validation from --vmlinux
Date: Mon, 12 Oct 2020 17:31:48 -0700	[thread overview]
Message-ID: <20201013003203.4168817-11-samitolvanen@google.com> (raw)
In-Reply-To: <20201013003203.4168817-1-samitolvanen@google.com>

This change adds a --noinstr flag to objtool to allow us to specify
that we're processing vmlinux.o without also enabling noinstr
validation. This is needed to avoid false positives with LTO when we
run objtool on vmlinux.o without CONFIG_DEBUG_ENTRY.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 scripts/link-vmlinux.sh       | 2 +-
 tools/objtool/builtin-check.c | 3 ++-
 tools/objtool/builtin.h       | 2 +-
 tools/objtool/check.c         | 2 +-
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 1a48ef525f46..5ace1dc43993 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -92,7 +92,7 @@ objtool_link()
 	local objtoolopt;
 
 	if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
-		objtoolopt="check --vmlinux"
+		objtoolopt="check --vmlinux --noinstr"
 		if [ -z "${CONFIG_FRAME_POINTER}" ]; then
 			objtoolopt="${objtoolopt} --no-fp"
 		fi
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index facfc10bc5dc..b84cdc72b51f 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -18,7 +18,7 @@
 #include "builtin.h"
 #include "objtool.h"
 
-bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount;
+bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount, noinstr;
 
 static const char * const check_usage[] = {
 	"objtool check [<options>] file.o",
@@ -34,6 +34,7 @@ const struct option check_options[] = {
 	OPT_BOOLEAN('a', "uaccess", &uaccess, "enable uaccess checking"),
 	OPT_BOOLEAN('s', "stats", &stats, "print statistics"),
 	OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"),
+	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_END(),
diff --git a/tools/objtool/builtin.h b/tools/objtool/builtin.h
index 94565a72b701..2502bb27de17 100644
--- a/tools/objtool/builtin.h
+++ b/tools/objtool/builtin.h
@@ -8,7 +8,7 @@
 #include <subcmd/parse-options.h>
 
 extern const struct option check_options[];
-extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount;
+extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount, noinstr;
 
 extern int cmd_check(int argc, const char **argv);
 extern int cmd_orc(int argc, const char **argv);
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index c39c4d2b432a..c216dd4d662c 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -244,7 +244,7 @@ static void init_insn_state(struct insn_state *state, struct section *sec)
 	 * not correctly determine insn->call_dest->sec (external symbols do
 	 * not have a section).
 	 */
-	if (vmlinux && sec)
+	if (vmlinux && noinstr && sec)
 		state->noinstr = sec->noinstr;
 }
 
-- 
2.28.0.1011.ga647a8990f-goog

