lib/test_static_keys.c

   1 /*
   2  * Kernel module for testing static keys.
   3  *
   4  * Copyright 2015 Akamai Technologies Inc. All Rights Reserved
   5  *
   6  * Authors:
   7  *      Jason Baron       <jbaron@akamai.com>
   8  *
   9  * This software is licensed under the terms of the GNU General Public
  10  * License version 2, as published by the Free Software Foundation, and
  11  * may be copied, distributed, and modified under those terms.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/jump_label.h>
  21
  22 /* old keys */
  23 struct static_key old_true_key  = STATIC_KEY_INIT_TRUE;
  24 struct static_key old_false_key = STATIC_KEY_INIT_FALSE;
  25
  26 /* new api */
  27 DEFINE_STATIC_KEY_TRUE(true_key);
  28 DEFINE_STATIC_KEY_FALSE(false_key);
  29
  30 /* external */
  31 extern struct static_key base_old_true_key;
  32 extern struct static_key base_inv_old_true_key;
  33 extern struct static_key base_old_false_key;
  34 extern struct static_key base_inv_old_false_key;
  35
  36 /* new api */
  37 extern struct static_key_true base_true_key;
  38 extern struct static_key_true base_inv_true_key;
  39 extern struct static_key_false base_false_key;
  40 extern struct static_key_false base_inv_false_key;
  41
  42
  43 struct test_key {
  44         bool                    init_state;
  45         struct static_key       *key;
  46         bool                    (*test_key)(void);
  47 };
  48
  49 #define test_key_func(key, branch)      \
  50 static bool key ## _ ## branch(void)    \
  51 {                                       \
  52         return branch(&key);            \
  53 }
  54
  55 static void invert_key(struct static_key *key)
  56 {
  57         if (static_key_enabled(key))
  58                 static_key_disable(key);
  59         else
  60                 static_key_enable(key);
  61 }
  62
  63 static void invert_keys(struct test_key *keys, int size)
  64 {
  65         struct static_key *previous = NULL;
  66         int i;
  67
  68         for (i = 0; i < size; i++) {
  69                 if (previous != keys[i].key) {
  70                         invert_key(keys[i].key);
  71                         previous = keys[i].key;
  72                 }
  73         }
  74 }
  75
  76 static int verify_keys(struct test_key *keys, int size, bool invert)
  77 {
  78         int i;
  79         bool ret, init;
  80
  81         for (i = 0; i < size; i++) {
  82                 ret = static_key_enabled(keys[i].key);
  83                 init = keys[i].init_state;
  84                 if (ret != (invert ? !init : init))
  85                         return -EINVAL;
  86                 ret = keys[i].test_key();
  87                 if (static_key_enabled(keys[i].key)) {
  88                         if (!ret)
  89                                 return -EINVAL;
  90                 } else {
  91                         if (ret)
  92                                 return -EINVAL;
  93                 }
  94         }
  95         return 0;
  96 }
  97
  98 test_key_func(old_true_key, static_key_true)
  99 test_key_func(old_false_key, static_key_false)
 100 test_key_func(true_key, static_branch_likely)
 101 test_key_func(true_key, static_branch_unlikely)
 102 test_key_func(false_key, static_branch_likely)
 103 test_key_func(false_key, static_branch_unlikely)
 104 test_key_func(base_old_true_key, static_key_true)
 105 test_key_func(base_inv_old_true_key, static_key_true)
 106 test_key_func(base_old_false_key, static_key_false)
 107 test_key_func(base_inv_old_false_key, static_key_false)
 108 test_key_func(base_true_key, static_branch_likely)
 109 test_key_func(base_true_key, static_branch_unlikely)
 110 test_key_func(base_inv_true_key, static_branch_likely)
 111 test_key_func(base_inv_true_key, static_branch_unlikely)
 112 test_key_func(base_false_key, static_branch_likely)
 113 test_key_func(base_false_key, static_branch_unlikely)
 114 test_key_func(base_inv_false_key, static_branch_likely)
 115 test_key_func(base_inv_false_key, static_branch_unlikely)
 116
 117 static int __init test_static_key_init(void)
 118 {
 119         int ret;
 120         int size;
 121
 122         struct test_key static_key_tests[] = {
 123                 /* internal keys - old keys */
 124                 {
 125                         .init_state     = true,
 126                         .key            = &old_true_key,
 127                         .test_key       = &old_true_key_static_key_true,
 128                 },
 129                 {
 130                         .init_state     = false,
 131                         .key            = &old_false_key,
 132                         .test_key       = &old_false_key_static_key_false,
 133                 },
 134                 /* internal keys - new keys */
 135                 {
 136                         .init_state     = true,
 137                         .key            = &true_key.key,
 138                         .test_key       = &true_key_static_branch_likely,
 139                 },
 140                 {
 141                         .init_state     = true,
 142                         .key            = &true_key.key,
 143                         .test_key       = &true_key_static_branch_unlikely,
 144                 },
 145                 {
 146                         .init_state     = false,
 147                         .key            = &false_key.key,
 148                         .test_key       = &false_key_static_branch_likely,
 149                 },
 150                 {
 151                         .init_state     = false,
 152                         .key            = &false_key.key,
 153                         .test_key       = &false_key_static_branch_unlikely,
 154                 },
 155                 /* external keys - old keys */
 156                 {
 157                         .init_state     = true,
 158                         .key            = &base_old_true_key,
 159                         .test_key       = &base_old_true_key_static_key_true,
 160                 },
 161                 {
 162                         .init_state     = false,
 163                         .key            = &base_inv_old_true_key,
 164                         .test_key       = &base_inv_old_true_key_static_key_true,
 165                 },
 166                 {
 167                         .init_state     = false,
 168                         .key            = &base_old_false_key,
 169                         .test_key       = &base_old_false_key_static_key_false,
 170                 },
 171                 {
 172                         .init_state     = true,
 173                         .key            = &base_inv_old_false_key,
 174                         .test_key       = &base_inv_old_false_key_static_key_false,
 175                 },
 176                 /* external keys - new keys */
 177                 {
 178                         .init_state     = true,
 179                         .key            = &base_true_key.key,
 180                         .test_key       = &base_true_key_static_branch_likely,
 181                 },
 182                 {
 183                         .init_state     = true,
 184                         .key            = &base_true_key.key,
 185                         .test_key       = &base_true_key_static_branch_unlikely,
 186                 },
 187                 {
 188                         .init_state     = false,
 189                         .key            = &base_inv_true_key.key,
 190                         .test_key       = &base_inv_true_key_static_branch_likely,
 191                 },
 192                 {
 193                         .init_state     = false,
 194                         .key            = &base_inv_true_key.key,
 195                         .test_key       = &base_inv_true_key_static_branch_unlikely,
 196                 },
 197                 {
 198                         .init_state     = false,
 199                         .key            = &base_false_key.key,
 200                         .test_key       = &base_false_key_static_branch_likely,
 201                 },
 202                 {
 203                         .init_state     = false,
 204                         .key            = &base_false_key.key,
 205                         .test_key       = &base_false_key_static_branch_unlikely,
 206                 },
 207                 {
 208                         .init_state     = true,
 209                         .key            = &base_inv_false_key.key,
 210                         .test_key       = &base_inv_false_key_static_branch_likely,
 211                 },
 212                 {
 213                         .init_state     = true,
 214                         .key            = &base_inv_false_key.key,
 215                         .test_key       = &base_inv_false_key_static_branch_unlikely,
 216                 },
 217         };
 218
 219         size = ARRAY_SIZE(static_key_tests);
 220
 221         ret = verify_keys(static_key_tests, size, false);
 222         if (ret)
 223                 goto out;
 224
 225         invert_keys(static_key_tests, size);
 226         ret = verify_keys(static_key_tests, size, true);
 227         if (ret)
 228                 goto out;
 229
 230         invert_keys(static_key_tests, size);
 231         ret = verify_keys(static_key_tests, size, false);
 232         if (ret)
 233                 goto out;
 234         return 0;
 235 out:
 236         return ret;
 237 }
 238
 239 static void __exit test_static_key_exit(void)
 240 {
 241 }
 242
 243 module_init(test_static_key_init);
 244 module_exit(test_static_key_exit);
 245
 246 MODULE_AUTHOR("Jason Baron <jbaron@akamai.com>");
 247 MODULE_LICENSE("GPL");