linux-kernel - [PATCH 1/8] objtool: Don't report end of section error after an empty unwind hint

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Message-Id: <b0dee2f38c09dab079168c4c28a28bb8ff0a8f44.1504210919.git.jpoimboe@redhat.com>
Date:   Thu, 31 Aug 2017 15:23:39 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     x86@...nel.org
Cc:     Jiri Slaby <jslaby@...e.cz>, linux-kernel@...r.kernel.org,
        Andy Lutomirski <luto@...nel.org>
Subject: [PATCH 1/8] objtool: Don't report end of section error after an empty unwind hint

If asm code specifies an UNWIND_HINT_EMPTY hint, don't warn if the
section ends unexpectedly.  This can happen with the xen-head.S code
because the hypercall_page is "text" but it's all zeros.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 tools/objtool/check.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f744617c9946..d8683f0fe04d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1737,11 +1737,14 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
 		if (insn->dead_end)
 			return 0;
 
-		insn = next_insn;
-		if (!insn) {
+		if (!next_insn) {
+			if (state.cfa.base == CFI_UNDEFINED)
+				return 0;
 			WARN("%s: unexpected end of section", sec->name);
 			return 1;
 		}
+
+		insn = next_insn;
 	}
 
 	return 0;
-- 
2.13.5