> Should objtool be made aware of the config option and then not check > traps after no-returns? > > I suspect the latter, but I'm not sure how feasible it is to > implement. Josh, Marco, do you have thoughts on the above?
This seems to do the trick. diff --git a/tools/objtool/check.c b/tools/objtool/check.c index e034a8f24f46..9224e6565ba2 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2612,9 +2612,10 @@ static bool is_ubsan_insn(struct instruction *insn) "__ubsan_handle_builtin_unreachable")); } -static bool ignore_unreachable_insn(struct instruction *insn) +static bool ignore_unreachable_insn(struct objtool_file *file, struct instruction *insn) { int i; + struct instruction *prev_insn; if (insn->ignore || insn->type == INSN_NOP) return true; @@ -2640,7 +2641,8 @@ static bool ignore_unreachable_insn(struct instruction *insn) * the UD2, which causes GCC's undefined trap logic to emit another UD2 * (or occasionally a JMP to UD2). */ - if (list_prev_entry(insn, list)->dead_end && + prev_insn = list_prev_entry(insn, list); + if ((prev_insn->dead_end || dead_end_function(file, prev_insn->call_dest)) && (insn->type == INSN_BUG || (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest && insn->jump_dest->type == INSN_BUG))) @@ -2767,7 +2769,7 @@ static int validate_reachable_instructions(struct objtool_file *file) return 0; for_each_insn(file, insn) { - if (insn->visited || ignore_unreachable_insn(insn)) + if (insn->visited || ignore_unreachable_insn(file, insn)) continue; WARN_FUNC("unreachable instruction", insn->sec, insn->offset);