[PATCH 3/3] objtool: check: Handle calling non-function symbols in other sections

From: Julien Thierry
Date: Tue Sep 15 2020 - 03:55:11 EST


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@xxxxxxxxxx>
---
tools/objtool/check.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index cd7c6698d316..500f63b3dcff 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 +861,9 @@ 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,
--
2.21.3