From 871caad2a47b3564c39072ed9e9f19d6fd9ec5ca Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 31 Jan 2018 10:18:28 +0100
Subject: objtool: Add module specific retpoline rules

commit ca41b97ed9124fd62323a162de5852f6e28f94b8 upstream.

David allowed retpolines in .init.text, except for modules, which will
trip up objtool retpoline validation, fix that.

Requested-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 tools/objtool/builtin-check.c | 3 ++-
 tools/objtool/builtin.h       | 2 +-
 tools/objtool/check.c         | 9 +++++++++
 3 files changed, 12 insertions(+), 2 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index dd6bcd6097f5..694abc628e9b 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -29,7 +29,7 @@
 #include "builtin.h"
 #include "check.h"
 
-bool no_fp, no_unreachable, retpoline;
+bool no_fp, no_unreachable, retpoline, module;
 
 static const char * const check_usage[] = {
 	"objtool check [<options>] file.o",
@@ -40,6 +40,7 @@ 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_END(),
 };
 
diff --git a/tools/objtool/builtin.h b/tools/objtool/builtin.h
index 7b6addfce045..28ff40e19a14 100644
--- a/tools/objtool/builtin.h
+++ b/tools/objtool/builtin.h
@@ -20,7 +20,7 @@
 #include <subcmd/parse-options.h>
 
 extern const struct option check_options[];
-extern bool no_fp, no_unreachable, retpoline;
+extern bool no_fp, no_unreachable, retpoline, module;
 
 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 d592fb5d0683..9a9d3a102523 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1957,6 +1957,15 @@ static int validate_retpoline(struct objtool_file *file)
 		if (insn->retpoline_safe)
 			continue;
 
+		/*
+		 * .init.text code is ran before userspace and thus doesn't
+		 * strictly need retpolines, except for modules which are
+		 * loaded late, they very much do need retpoline in their
+		 * .init.text
+		 */
+		if (!strcmp(insn->sec->name, ".init.text") && !module)
+			continue;
+
 		WARN_FUNC("indirect %s found in RETPOLINE build",
 			  insn->sec, insn->offset,
 			  insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call");
-- 
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