lib/livepatch/test_klp_callbacks_demo.c

   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
  10 static int pre_patch_ret;
  11 module_param(pre_patch_ret, int, 0644);
  12 MODULE_PARM_DESC(pre_patch_ret, "pre_patch_ret (default=0)");
  13
  14 static 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
  21 static 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) */
  31 static 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) */
  38 static void post_patch_callback(struct klp_object *obj)
  39 {
  40         callback_info(__func__, obj);
  41 }
  42
  43 /* Executed on object unpatching (ie, patch disablement) */
  44 static void pre_unpatch_callback(struct klp_object *obj)
  45 {
  46         callback_info(__func__, obj);
  47 }
  48
  49 /* Executed on object unpatching (ie, patch disablement) */
  50 static void post_unpatch_callback(struct klp_object *obj)
  51 {
  52         callback_info(__func__, obj);
  53 }
  54
  55 static void patched_work_func(struct work_struct *work)
  56 {
  57         pr_info("%s\n", __func__);
  58 }
  59
  60 static struct klp_func no_funcs[] = {
  61         {}
  62 };
  63
  64 static struct klp_func busymod_funcs[] = {
  65         {
  66                 .old_name = "busymod_work_func",
  67                 .new_func = patched_work_func,
  68         }, {}
  69 };
  70
  71 static 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
 102 static struct klp_patch patch = {
 103         .mod = THIS_MODULE,
 104         .objs = objs,
 105 };
 106
 107 static int test_klp_callbacks_demo_init(void)
 108 {
 109         return klp_enable_patch(&patch);
 110 }
 111
 112 static void test_klp_callbacks_demo_exit(void)
 113 {
 114 }
 115
 116 module_init(test_klp_callbacks_demo_init);
 117 module_exit(test_klp_callbacks_demo_exit);
 118 MODULE_LICENSE("GPL");
 119 MODULE_INFO(livepatch, "Y");
 120 MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
 121 MODULE_DESCRIPTION("Livepatch test: livepatch demo");