jump-label: initialize jump-label subsystem much earlier

Initialize jump_labels much, much earlier, so they're available for use
during system setup.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

3 files changed, 13 insertions, 9 deletions

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 56594e45b011..388b0d425b50 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -16,7 +16,7 @@ struct jump_label_key {
 
 # include <asm/jump_label.h>
 # define HAVE_JUMP_LABEL
-#endif
+#endif  /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */
 
 enum jump_label_type {
         JUMP_LABEL_DISABLE = 0,
@@ -41,6 +41,7 @@ static __always_inline bool static_branch(struct jump_label_key *key)
 extern struct jump_entry __start___jump_table[];
 extern struct jump_entry __stop___jump_table[];
 
+extern void jump_label_init(void);
 extern void jump_label_lock(void);
 extern void jump_label_unlock(void);
 extern void arch_jump_label_transform(struct jump_entry *entry,
@@ -53,7 +54,7 @@ extern void jump_label_dec(struct jump_label_key *key);
 extern bool jump_label_enabled(struct jump_label_key *key);
 extern void jump_label_apply_nops(struct module *mod);
 
-#else
+#else  /* !HAVE_JUMP_LABEL */
 
 #include <linux/atomic.h>
 
@@ -63,6 +64,10 @@ struct jump_label_key {
         atomic_t enabled;
 };
 
+static __always_inline void jump_label_init(void)
+{
+}
+
 static __always_inline bool static_branch(struct jump_label_key *key)
 {
         if (unlikely(atomic_read(&key->enabled)))
@@ -97,7 +102,6 @@ static inline int jump_label_apply_nops(struct module *mod)
 {
         return 0;
 }
+#endif  /* HAVE_JUMP_LABEL */
 
-#endif
-
-#endif
+#endif  /* _LINUX_JUMP_LABEL_H */
diff --git a/init/main.c b/init/main.c
index 2a9b88aa5e76..29d8d847de94 100644
--- a/init/main.c
+++ b/init/main.c
@@ -515,6 +515,9 @@ asmlinkage void __init start_kernel(void)
         parse_args("Booting kernel", static_command_line, __start___param,
                    __stop___param - __start___param,
                    &unknown_bootoption);
+
+        jump_label_init();
+
         /*
          * These use large bootmem allocations and must precede
          * kmem_cache_init()
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index ff2028f35aa8..bbdfe2a462a0 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -133,7 +133,7 @@ static void __jump_label_update(struct jump_label_key *key,
         }
 }
 
-static __init int jump_label_init(void)
+void __init jump_label_init(void)
 {
         struct jump_entry *iter_start = __start___jump_table;
         struct jump_entry *iter_stop = __stop___jump_table;
@@ -159,10 +159,7 @@ static __init int jump_label_init(void)
 #endif
         }
         jump_label_unlock();
-
-        return 0;
 }
-early_initcall(jump_label_init);
 
 #ifdef CONFIG_MODULES