linux-kernel - [tip: objtool/core] objtool: Handle calling non-function symbols in other sections

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Date:   Mon, 21 Sep 2020 16:51:11 -0000
From:   "tip-bot2 for Julien Thierry" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Julien Thierry <jthierry@...hat.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: objtool/core] objtool: Handle calling non-function symbols in
 other sections

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     2b232a22d8225df419a92ca69ddeeb4e5fe902f7
Gitweb:        https://git.kernel.org/tip/2b232a22d8225df419a92ca69ddeeb4e5fe902f7
Author:        Julien Thierry <jthierry@...hat.com>
AuthorDate:    Tue, 15 Sep 2020 08:53:18 +01:00
Committer:     Josh Poimboeuf <jpoimboe@...hat.com>
CommitterDate: Mon, 21 Sep 2020 10:17:36 -05:00

objtool: Handle calling non-function symbols in other sections

Relocation for a call destination could point to a symbol that has
type STT_NOTYPE.

Lookup such a symbol when no function is available.

Signed-off-by: Julien Thierry <jthierry@...hat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 tools/objtool/check.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index cd7c669..a4796e3 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -815,6 +815,17 @@ static void remove_insn_ops(struct instruction *insn)
 	}
 }
 
+static struct symbol *find_call_destination(struct section *sec, unsigned long offset)
+{
+	struct symbol *call_dest;
+
+	call_dest = find_func_by_offset(sec, offset);
+	if (!call_dest)
+		call_dest = find_symbol_by_offset(sec, offset);
+
+	return call_dest;
+}
+
 /*
  * Find the destination instructions for all calls.
  */
@@ -832,9 +843,7 @@ static int add_call_destinations(struct objtool_file *file)
 					       insn->offset, insn->len);
 		if (!reloc) {
 			dest_off = arch_jump_destination(insn);
-			insn->call_dest = find_func_by_offset(insn->sec, dest_off);
-			if (!insn->call_dest)
-				insn->call_dest = find_symbol_by_offset(insn->sec, dest_off);
+			insn->call_dest = find_call_destination(insn->sec, dest_off);
 
 			if (insn->ignore)
 				continue;
@@ -852,8 +861,8 @@ static int add_call_destinations(struct objtool_file *file)
 
 		} else if (reloc->sym->type == STT_SECTION) {
 			dest_off = arch_dest_reloc_offset(reloc->addend);
-			insn->call_dest = find_func_by_offset(reloc->sym->sec,
-							      dest_off);
+			insn->call_dest = find_call_destination(reloc->sym->sec,
+								dest_off);
 			if (!insn->call_dest) {
 				WARN_FUNC("can't find call dest symbol at %s+0x%lx",
 					  insn->sec, insn->offset,