The __cfi_ preambles contain a mov instruction that embeds the KCFI
type identifier in the following format:
; type preamble
__cfi_function:
mov <id>, %eax
function:
...
While the preamble symbols are STT_FUNC and contain valid
instructions, they are never executed and always fall through. Skip
the warning for them.
.kcfi_traps sections point to CFI traps in text sections. Also skip
the warning about them referencing !ENDBR instructions.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e55fdf952a3a..48e18737a2d1 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3316,6 +3316,10 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
next_insn = next_insn_to_validate(file, insn);
if (func && insn->func && func != insn->func->pfunc) {
+ /* Ignore KCFI type preambles, which always fall through */
+ if (!strncmp(func->name, "__cfi_", 6))
+ return 0;
+
WARN("%s() falls through to next function %s()",
func->name, insn->func->name);
return 1;
@@ -4113,7 +4117,8 @@ static int validate_ibt(struct objtool_file *file)
!strcmp(sec->name, "__bug_table") ||
!strcmp(sec->name, "__ex_table") ||
!strcmp(sec->name, "__jump_table") ||
- !strcmp(sec->name, "__mcount_loc"))
+ !strcmp(sec->name, "__mcount_loc") ||
+ !strcmp(sec->name, ".kcfi_traps"))
continue;
list_for_each_entry(reloc, &sec->reloc->reloc_list, list)
--
2.37.2.672.g94769d06f0-goog