[PATCH v3 10/21] objtool: Ignore jumps to the end of the function for checksum runs

Sometimes Clang arm64 code jumps to the end of the function for UB.
No need to make that an error for checksum runs.

Signed-off-by: Josh Poimboeuf <[email protected]>
---
 tools/objtool/check.c | 42 +++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 10b18cf9c3608..73451aef68029 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -37,6 +37,22 @@ struct disas_context *objtool_disas_ctx;
 
 size_t sym_name_max_len;
 
+static bool validate_branch_enabled(void)
+{
+	return opts.stackval	||
+	       opts.orc		||
+	       opts.uaccess;
+}
+
+static bool alts_needed(void)
+{
+	return validate_branch_enabled()	||
+	       opts.noinstr			||
+	       opts.hack_jump_label		||
+	       opts.disas			||
+	       opts.checksum;
+}
+
 struct instruction *find_insn(struct objtool_file *file,
 			      struct section *sec, unsigned long offset)
 {
@@ -1593,10 +1609,14 @@ static int add_jump_destinations(struct objtool_file *file)
 			/*
 			 * GCOV/KCOV dead code can jump to the end of
 			 * the function/section.
+			 *
+			 * Clang on arm64 also does this sometimes for
+			 * undefined behavior.
 			 */
-			if (file->ignore_unreachables && func &&
-			    dest_sec == insn->sec &&
-			    dest_off == func->offset + func->len)
+			if (!validate_branch_enabled() ||
+			    (file->ignore_unreachables && func &&
+			     dest_sec == insn->sec &&
+			     dest_off == func->offset + func->len))
 				continue;
 
 			ERROR_INSN(insn, "can't find jump dest instruction at %s",
@@ -2584,22 +2604,6 @@ static void mark_holes(struct objtool_file *file)
 	}
 }
 
-static bool validate_branch_enabled(void)
-{
-	return opts.stackval	||
-	       opts.orc		||
-	       opts.uaccess;
-}
-
-static bool alts_needed(void)
-{
-	return validate_branch_enabled()	||
-	       opts.noinstr			||
-	       opts.hack_jump_label		||
-	       opts.disas			||
-	       opts.checksum;
-}
-
 int decode_file(struct objtool_file *file)
 {
 	arch_initial_func_cfi_state(&initial_func_cfi);
-- 
2.53.0