livepatch/module: remove livepatch module notifier

Remove the livepatch module notifier in favor of directly enabling and
disabling patches to modules in the module loader. Hard-coding the
function calls ensures that ftrace_module_enable() is run before
klp_module_coming() during module load, and that klp_module_going() is
run before ftrace_release_mod() during module unload. This way, ftrace
and livepatch code is run in the correct order during the module
load/unload sequence without dependence on the module notifier call chain.

Signed-off-by: Jessica Yu <jeyu@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index c05679701e10..bd830d590465 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -24,6 +24,8 @@
 #include <linux/module.h>
 #include <linux/ftrace.h>
 
+#if IS_ENABLED(CONFIG_LIVEPATCH)
+
 #include <asm/livepatch.h>
 
 enum klp_state {
@@ -132,4 +134,15 @@ int klp_unregister_patch(struct klp_patch *);
 int klp_enable_patch(struct klp_patch *);
 int klp_disable_patch(struct klp_patch *);
 
+/* Called from the module loader during module coming/going states */
+int klp_module_coming(struct module *mod);
+void klp_module_going(struct module *mod);
+
+#else /* !CONFIG_LIVEPATCH */
+
+static inline int klp_module_coming(struct module *mod) { return 0; }
+static inline void klp_module_going(struct module *mod) { }
+
+#endif /* CONFIG_LIVEPATCH */
+
 #endif /* _LINUX_LIVEPATCH_H_ */