Commit 59adee07 authored by Josh Poimboeuf's avatar Josh Poimboeuf
Browse files

livepatch/klp-build: Add stub init code for livepatch modules 



Add a module initialization stub which can be linked with binary diff
objects to produce a livepatch module.

Acked-by: default avatarPetr Mladek <pmladek@suse.com>
Tested-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
parent abaf1f42

scripts/livepatch/init.c

0 → 100644
+108 −0
Original line number Diff line number Diff line 
// 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");