1// SPDX-License-Identifier: GPL-2.0
  2// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
  3
  4#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  5
  6#include <linux/module.h>
  7#include <linux/kernel.h>
  8#include <linux/livepatch.h>
  9
 10static int pre_patch_ret;
 11module_param(pre_patch_ret, int, 0644);
 12MODULE_PARM_DESC(pre_patch_ret, "pre_patch_ret (default=0)");
 13
 14static const char *const module_state[] = {
 15	[MODULE_STATE_LIVE]	= "[MODULE_STATE_LIVE] Normal state",
 16	[MODULE_STATE_COMING]	= "[MODULE_STATE_COMING] Full formed, running module_init",
 17	[MODULE_STATE_GOING]	= "[MODULE_STATE_GOING] Going away",
 18	[MODULE_STATE_UNFORMED]	= "[MODULE_STATE_UNFORMED] Still setting it up",
 19};
 20
 21static void callback_info(const char *callback, struct klp_object *obj)
 22{
 23	if (obj->mod)
 24		pr_info("%s: %s -> %s\n", callback, obj->mod->name,
 25			module_state[obj->mod->state]);
 26	else
 27		pr_info("%s: vmlinux\n", callback);
 28}
 29
 30/* Executed on object patching (ie, patch enablement) */
 31static int pre_patch_callback(struct klp_object *obj)
 32{
 33	callback_info(__func__, obj);
 34	return pre_patch_ret;
 35}
 36
 37/* Executed on object unpatching (ie, patch disablement) */
 38static void post_patch_callback(struct klp_object *obj)
 39{
 40	callback_info(__func__, obj);
 41}
 42
 43/* Executed on object unpatching (ie, patch disablement) */
 44static void pre_unpatch_callback(struct klp_object *obj)
 45{
 46	callback_info(__func__, obj);
 47}
 48
 49/* Executed on object unpatching (ie, patch disablement) */
 50static void post_unpatch_callback(struct klp_object *obj)
 51{
 52	callback_info(__func__, obj);
 53}
 54
 55static void patched_work_func(struct work_struct *work)
 56{
 57	pr_info("%s\n", __func__);
 58}
 59
 60static struct klp_func no_funcs[] = {
 61	{}
 62};
 63
 64static struct klp_func busymod_funcs[] = {
 65	{
 66		.old_name = "busymod_work_func",
 67		.new_func = patched_work_func,
 68	}, {}
 69};
 70
 71static struct klp_object objs[] = {
 72	{
 73		.name = NULL,	/* vmlinux */
 74		.funcs = no_funcs,
 75		.callbacks = {
 76			.pre_patch = pre_patch_callback,
 77			.post_patch = post_patch_callback,
 78			.pre_unpatch = pre_unpatch_callback,
 79			.post_unpatch = post_unpatch_callback,
 80		},
 81	},	{
 82		.name = "test_klp_callbacks_mod",
 83		.funcs = no_funcs,
 84		.callbacks = {
 85			.pre_patch = pre_patch_callback,
 86			.post_patch = post_patch_callback,
 87			.pre_unpatch = pre_unpatch_callback,
 88			.post_unpatch = post_unpatch_callback,
 89		},
 90	},	{
 91		.name = "test_klp_callbacks_busy",
 92		.funcs = busymod_funcs,
 93		.callbacks = {
 94			.pre_patch = pre_patch_callback,
 95			.post_patch = post_patch_callback,
 96			.pre_unpatch = pre_unpatch_callback,
 97			.post_unpatch = post_unpatch_callback,
 98		},
 99	}, { }
100};
101
102static struct klp_patch patch = {
103	.mod = THIS_MODULE,
104	.objs = objs,
105};
106
107static int test_klp_callbacks_demo_init(void)
108{
109	return klp_enable_patch(&patch);
110}
111
112static void test_klp_callbacks_demo_exit(void)
113{
114}
115
116module_init(test_klp_callbacks_demo_init);
117module_exit(test_klp_callbacks_demo_exit);
118MODULE_LICENSE("GPL");
119MODULE_INFO(livepatch, "Y");
120MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
121MODULE_DESCRIPTION("Livepatch test: livepatch demo");