Add a module initialization stub which can be linked with binary diff
objects to produce a livepatch module.
Signed-off-by: Josh Poimboeuf <jpoim...@kernel.org>
---
scripts/livepatch/init.c | 108 +++++++++++++++++++++++++++++++++++++++
1 file changed, 108 insertions(+)
create mode 100644 scripts/livepatch/init.c
diff --git a/scripts/livepatch/init.c b/scripts/livepatch/init.c
new file mode 100644
index 000000000000..2274d8f5a482
--- /dev/null
+++ b/scripts/livepatch/init.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Init code for a livepatch kernel module
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/livepatch.h>
+
+extern struct klp_object_ext __start_klp_objects[];
+extern struct klp_object_ext __stop_klp_objects[];
+
+static struct klp_patch *patch;
+
+static int __init livepatch_mod_init(void)
+{
+ struct klp_object *objs;
+ unsigned int nr_objs;
+ int ret;
+
+ nr_objs = __stop_klp_objects - __start_klp_objects;
+
+ if (!nr_objs) {
+ pr_err("nothing to patch!\n");
+ ret = -EINVAL;
+ goto err;
+ }
+
+ patch = kzalloc(sizeof(*patch), GFP_KERNEL);
+ if (!patch) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ objs = kzalloc(sizeof(struct klp_object) * (nr_objs + 1), GFP_KERNEL);
+ if (!objs) {
+ ret = -ENOMEM;
+ goto err_free_patch;
+ }
+
+ for (int i = 0; i < nr_objs; i++) {
+ struct klp_object_ext *obj_ext = __start_klp_objects + i;
+ struct klp_func_ext *funcs_ext = obj_ext->funcs;
+ unsigned int nr_funcs = obj_ext->nr_funcs;
+ struct klp_func *funcs = objs[i].funcs;
+ struct klp_object *obj = objs + i;
+
+ funcs = kzalloc(sizeof(struct klp_func) * (nr_funcs + 1),
GFP_KERNEL);
+ if (!funcs) {
+ ret = -ENOMEM;
+ for (int j = 0; j < i; j++)
+ kfree(objs[i].funcs);
+ goto err_free_objs;
+ }
+
+ for (int j = 0; j < nr_funcs; j++) {
+ funcs[j].old_name = funcs_ext[j].old_name;
+ funcs[j].new_func = funcs_ext[j].new_func;
+ funcs[j].old_sympos = funcs_ext[j].sympos;
+ }
+
+ obj->name = obj_ext->name;
+ obj->funcs = funcs;
+
+ memcpy(&obj->callbacks, &obj_ext->callbacks, sizeof(struct
klp_callbacks));
+ }
+
+ patch->mod = THIS_MODULE;
+ patch->objs = objs;
+
+ /* TODO patch->states */
+
+#ifdef KLP_NO_REPLACE
+ patch->replace = false;
+#else
+ patch->replace = true;
+#endif
+
+ return klp_enable_patch(patch);
+
+err_free_objs:
+ kfree(objs);
+err_free_patch:
+ kfree(patch);
+err:
+ return ret;
+}
+
+static void __exit livepatch_mod_exit(void)
+{
+ unsigned int nr_objs;
+
+ nr_objs = __stop_klp_objects - __start_klp_objects;
+
+ for (int i = 0; i < nr_objs; i++)
+ kfree(patch->objs[i].funcs);
+
+ kfree(patch->objs);
+ kfree(patch);
+}
+
+module_init(livepatch_mod_init);
+module_exit(livepatch_mod_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_DESCRIPTION("Livepatch module");
--
2.49.0
