objtool: Warn on zero-length functions

All callable functions should have an ELF size.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/03d429c4fa87829c61c5dc0e89652f4d9efb62f1.1563413318.git.jpoimboe@redhat.com

1 files changed, 6 insertions, 0 deletions

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 3f8664b0e3f9..dece3253ff6a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2357,6 +2357,12 @@ static int validate_functions(struct objtool_file *file)
                         if (func->type != STT_FUNC)
                                 continue;
 
+                        if (!func->len) {
+                                WARN("%s() is missing an ELF size annotation",
+                                     func->name);
+                                warnings++;
+                        }
+
                         if (func->pfunc != func || func->alias != func)
                                 continue;