Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core fixes from Ingo Molnar:
 "A handful of objtool updates, plus a documentation addition for
  __ab_c_size()"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix whitelist documentation typo
  objtool: Fix function fallthrough detection
  objtool: Don't use ignore flag for fake jumps
  overflow.h: Add comment documenting __ab_c_size()

include/linux/overflow.h

@@ -284,11 +284,15 @@ static inline __must_check size_t array3_size(size_t a, size_t b, size_t c)
 	return bytes;
 }
 
-static inline __must_check size_t __ab_c_size(size_t n, size_t size, size_t c)
+/*
+ * Compute a*b+c, returning SIZE_MAX on overflow. Internal helper for
+ * struct_size() below.
+ */
+static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c)
 {
 	size_t bytes;
 
-	if (check_mul_overflow(n, size, &bytes))
+	if (check_mul_overflow(a, b, &bytes))
 		return SIZE_MAX;
 	if (check_add_overflow(bytes, c, &bytes))
 		return SIZE_MAX;

tools/objtool/Documentation/stack-validation.txt

@@ -306,7 +306,7 @@ ignore it:
 
 - To skip validation of a file, add
 
-    OBJECT_FILES_NON_STANDARD_filename.o := n
+    OBJECT_FILES_NON_STANDARD_filename.o := y
 
   to the Makefile.
 

tools/objtool/check.c

@@ -28,6 +28,8 @@
 #include <linux/hashtable.h>
 #include <linux/kernel.h>
 
+#define FAKE_JUMP_OFFSET -1
+
 struct alternative {
 	struct list_head list;
 	struct instruction *insn;
@@ -568,7 +570,7 @@ static int add_jump_destinations(struct objtool_file *file)
 		    insn->type != INSN_JUMP_UNCONDITIONAL)
 			continue;
 
-		if (insn->ignore)
+		if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET)
 			continue;
 
 		rela = find_rela_by_dest_range(insn->sec, insn->offset,
@@ -745,10 +747,10 @@ static int handle_group_alt(struct objtool_file *file,
 		clear_insn_state(&fake_jump->state);
 
 		fake_jump->sec = special_alt->new_sec;
-		fake_jump->offset = -1;
+		fake_jump->offset = FAKE_JUMP_OFFSET;
 		fake_jump->type = INSN_JUMP_UNCONDITIONAL;
 		fake_jump->jump_dest = list_next_entry(last_orig_insn, list);
-		fake_jump->ignore = true;
+		fake_jump->func = orig_insn->func;
 	}
 
 	if (!special_alt->new_len) {
@@ -1957,7 +1959,8 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
 			return 1;
 		}
 
-		func = insn->func ? insn->func->pfunc : NULL;
+		if (insn->func)
+			func = insn->func->pfunc;
 
 		if (func && insn->ignore) {
 			WARN_FUNC("BUG: why am I validating an ignored function?",