objtool: Have WARN_FUNC fall back to sym+off

Currently WARN_FUNC() either prints func+off and failing that prints
sec+off, add an intermediate sym+off. This is useful when playing
around with entry code.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Peter Zijlstra

tools/objtool/include/objtool/warn.h

@@ -22,6 +22,8 @@ static inline char *offstr(struct section *sec, unsigned long offset)
 	unsigned long name_off;
 
 	func = find_func_containing(sec, offset);
+	if (!func)
+		func = find_symbol_containing(sec, offset);
 	if (func) {
 		name = func->name;
 		name_off = offset - func->offset;