objtool: Support repeated uses of the same C jump table

[platform/kernel/linux-starfive.git] / tools / objtool / check.c

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4525cf6..66f7c01 100644 (file)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -900,7 +900,7 @@ out:
 }
 
 static int add_jump_table(struct objtool_file *file, struct instruction *insn,
-                           struct rela *table, struct rela *next_table)
+                           struct rela *table)
 {
        struct rela *rela = table;
        struct instruction *dest_insn;
@@ -913,7 +913,9 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
         * instruction.
         */
        list_for_each_entry_from(rela, &table->sec->rela_list, list) {
-               if (rela == next_table)
+
+               /* Check for the end of the table: */
+               if (rela != table && rela->jump_table_start)
                        break;
 
                /* Make sure the table entries are consecutive: */
@@ -1072,13 +1074,15 @@ static struct rela *find_jump_table(struct objtool_file *file,
        return NULL;
 }
 
-
-static int add_func_jump_tables(struct objtool_file *file,
-                                 struct symbol *func)
+/*
+ * First pass: Mark the head of each jump table so that in the next pass,
+ * we know when a given jump table ends and the next one starts.
+ */
+static void mark_func_jump_tables(struct objtool_file *file,
+                                   struct symbol *func)
 {
-       struct instruction *insn, *last = NULL, *prev_jump = NULL;
-       struct rela *rela, *prev_rela = NULL;
-       int ret;
+       struct instruction *insn, *last = NULL;
+       struct rela *rela;
 
        func_for_each_insn_all(file, func, insn) {
                if (!last)
@@ -1102,26 +1106,24 @@ static int add_func_jump_tables(struct objtool_file *file,
                        continue;
 
                rela = find_jump_table(file, func, insn);
-               if (!rela)
-                       continue;
-
-               /*
-                * We found a jump table, but we don't know yet how big it
-                * is.  Don't add it until we reach the end of the function or
-                * the beginning of another jump table in the same function.
-                */
-               if (prev_jump) {
-                       ret = add_jump_table(file, prev_jump, prev_rela, rela);
-                       if (ret)
-                               return ret;
+               if (rela) {
+                       rela->jump_table_start = true;
+                       insn->jump_table = rela;
                }
-
-               prev_jump = insn;
-               prev_rela = rela;
        }
+}
+
+static int add_func_jump_tables(struct objtool_file *file,
+                                 struct symbol *func)
+{
+       struct instruction *insn;
+       int ret;
+
+       func_for_each_insn_all(file, func, insn) {
+               if (!insn->jump_table)
+                       continue;
 
-       if (prev_jump) {
-               ret = add_jump_table(file, prev_jump, prev_rela, NULL);
+               ret = add_jump_table(file, insn, insn->jump_table);
                if (ret)
                        return ret;
        }
@@ -1148,6 +1150,7 @@ static int add_jump_table_alts(struct objtool_file *file)
                        if (func->type != STT_FUNC)
                                continue;
 
+                       mark_func_jump_tables(file, func);
                        ret = add_func_jump_tables(file, func);
                        if (ret)
                                return ret;