1 files changed, 35 insertions, 33 deletions

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 143b6cdd7f06..e8a1f699058a 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -97,6 +97,19 @@ static struct instruction *next_insn_same_sec(struct objtool_file *file,
         return next;
 }
 
+static bool gcov_enabled(struct objtool_file *file)
+{
+        struct section *sec;
+        struct symbol *sym;
+
+        list_for_each_entry(sec, &file->elf->sections, list)
+                list_for_each_entry(sym, &sec->symbol_list, list)
+                        if (!strncmp(sym->name, "__gcov_.", 8))
+                                return true;
+
+        return false;
+}
+
 #define for_each_insn(file, insn)                                       \
         list_for_each_entry(insn, &file->insn_list, list)
 
@@ -713,6 +726,7 @@ 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 +747,16 @@ 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)
@@ -1034,34 +1054,6 @@ static int validate_branch(struct objtool_file *file,
         return 0;
 }
 
-static bool is_gcov_insn(struct instruction *insn)
-{
-        struct rela *rela;
-        struct section *sec;
-        struct symbol *sym;
-        unsigned long offset;
-
-        rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len);
-        if (!rela)
-                return false;
-
-        if (rela->sym->type != STT_SECTION)
-                return false;
-
-        sec = rela->sym->sec;
-        offset = rela->addend + insn->offset + insn->len - rela->offset;
-
-        list_for_each_entry(sym, &sec->symbol_list, list) {
-                if (sym->type != STT_OBJECT)
-                        continue;
-
-                if (offset >= sym->offset && offset < sym->offset + sym->len)
-                        return (!memcmp(sym->name, "__gcov0.", 8));
-        }
-
-        return false;
-}
-
 static bool is_kasan_insn(struct instruction *insn)
 {
         return (insn->type == INSN_CALL &&
@@ -1083,9 +1075,6 @@ static bool ignore_unreachable_insn(struct symbol *func,
         if (insn->type == INSN_NOP)
                 return true;
 
-        if (is_gcov_insn(insn))
-                return true;
-
         /*
          * Check if this (or a subsequent) instruction is related to
          * CONFIG_UBSAN or CONFIG_KASAN.
@@ -1146,6 +1135,19 @@ static int validate_functions(struct objtool_file *file)
                                     ignore_unreachable_insn(func, insn))
                                         continue;
 
+                                /*
+                                 * gcov produces a lot of unreachable
+                                 * instructions.  If we get an unreachable
+                                 * warning and the file has gcov enabled, just
+                                 * ignore it, and all other such warnings for
+                                 * the file.
+                                 */
+                                if (!file->ignore_unreachables &&
+                                    gcov_enabled(file)) {
+                                        file->ignore_unreachables = true;
+                                        continue;
+                                }
+
                                 WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset);
                                 warnings++;
                         }