objtool: Do frame pointer check before dead end check

Even calls to __noreturn functions need the frame pointer setup first.
Such functions often dump the stack.

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/aed62fbd60e239280218be623f751a433658e896.1563413318.git.jpoimboe@redhat.com

1 files changed, 9 insertions, 9 deletions

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d9d1c9b54947..0d2a8e54a82e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -133,6 +133,9 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
                 "rewind_stack_do_exit",
         };
 
+        if (!func)
+                return false;
+
         if (func->bind == STB_WEAK)
                 return false;
 
@@ -2071,19 +2074,16 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
                         if (ret)
                                 return ret;
 
-                        if (insn->type == INSN_CALL) {
-                                if (is_fentry_call(insn))
-                                        break;
-
-                                if (dead_end_function(file, insn->call_dest))
-                                        return 0;
-                        }
-
-                        if (!no_fp && func && !has_valid_stack_frame(&state)) {
+                        if (!no_fp && func && !is_fentry_call(insn) &&
+                            !has_valid_stack_frame(&state)) {
                                 WARN_FUNC("call without frame pointer save/setup",
                                           sec, insn->offset);
                                 return 1;
                         }
+
+                        if (dead_end_function(file, insn->call_dest))
+                                return 0;
+
                         break;
 
                 case INSN_JUMP_CONDITIONAL: