objtool: Improve rare switch jump table pattern detection

[cascardo/linux.git] / tools / objtool / builtin-check.c

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 143b6cd..a00a05d 100644 (file)
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -713,6 +713,7 @@ static struct rela *find_switch_table(struct objtool_file *file,
                                      struct instruction *insn)
 {
        struct rela *text_rela, *rodata_rela;
+       struct instruction *orig_insn = insn;
 
        text_rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len);
        if (text_rela && text_rela->sym == file->rodata->sym) {
@@ -733,10 +734,16 @@ static struct rela *find_switch_table(struct objtool_file *file,
 
        /* case 3 */
        func_for_each_insn_continue_reverse(file, func, insn) {
-               if (insn->type == INSN_JUMP_UNCONDITIONAL ||
-                   insn->type == INSN_JUMP_DYNAMIC)
+               if (insn->type == INSN_JUMP_DYNAMIC)
                        break;
 
+               /* allow small jumps within the range */
+               if (insn->type == INSN_JUMP_UNCONDITIONAL &&
+                   insn->jump_dest &&
+                   (insn->jump_dest->offset <= insn->offset ||
+                    insn->jump_dest->offset >= orig_insn->offset))
+                   break;
+
                text_rela = find_rela_by_dest_range(insn->sec, insn->offset,
                                                    insn->len);
                if (text_rela && text_rela->sym == file->rodata->sym)