Re: [PATCH v3 26/26] objtool: Add STT_NOTYPE noinstr validation

[Peter Zijlstra <peterz@infradead.org>]

On Wed, Mar 25, 2020 at 09:42:11AM -0500, Josh Poimboeuf wrote:
> Sure, but couldn't validate_unwind_hints() and
> validate_reachable_instructions() be changed to *only* run on
> .noinstr.text, for the vmlinux case?  That might help converge the
> vmlinux and !vmlinux paths.

You're thinking something like so then?

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2421,24 +2421,34 @@ static int validate_branch(struct objtoo
 	return 0;
 }
 
-static int validate_unwind_hints(struct objtool_file *file)
+static int validate_unwind_hints(struct objtool_file *file, struct section *sec)
 {
 	struct instruction *insn;
-	int ret, warnings = 0;
 	struct insn_state state;
+	int ret, warnings = 0;
 
 	if (!file->hints)
 		return 0;
 
 	clear_insn_state(&state);
 
-	for_each_insn(file, insn) {
+	if (sec) {
+		insn = find_insn(file, sec, 0);
+		if (!insn)
+			return 0;
+	} else {
+		insn = list_first_entry(&file->insn_list, typeof(*insn), list);
+	}
+
+	while (&insn->list != &file->insn_list && (!sec || insn->sec == sec)) {
 		if (insn->hint && !insn->visited) {
 			ret = validate_branch(file, insn->func, insn, state);
 			if (ret && backtrace)
 				BT_FUNC("<=== (hint)", insn);
 			warnings += ret;
 		}
+
+		insn = list_next_entry(insn, list);
 	}
 
 	return warnings;
@@ -2622,12 +2632,16 @@ static int validate_section(struct objto
 static int validate_vmlinux_functions(struct objtool_file *file)
 {
 	struct section *sec;
+	int warnings = 0;
 
 	sec = find_section_by_name(file->elf, ".noinstr.text");
 	if (!sec)
 		return 0;
 
-	return validate_section(file, sec);
+	warnings += validate_section(file, sec);
+	warnings += validate_unwind_hints(file, sec);
+
+	return warnings;
 }
 
 static int validate_functions(struct objtool_file *file)
@@ -2712,7 +2726,7 @@ int check(const char *_objname, bool orc
 		goto out;
 	warnings += ret;
 
-	ret = validate_unwind_hints(&file);
+	ret = validate_unwind_hints(&file, NULL);
 	if (ret < 0)
 		goto out;
 	warnings += ret;