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/*
* Kernel module for testing jump labels.
*
* Copyright 2015 Akamai Technologies Inc. All Rights Reserved
*
* Authors:
* Jason Baron <jbaron@akamai.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/module.h>
#include <linux/jump_label.h>
/* old keys */
struct static_key old_true_key = STATIC_KEY_INIT_TRUE;
struct static_key old_false_key = STATIC_KEY_INIT_FALSE;
/* new api */
DEFINE_STATIC_KEY_TRUE(true_key);
DEFINE_STATIC_KEY_FALSE(false_key);
/* external */
extern struct static_key base_old_true_key;
extern struct static_key base_inv_old_true_key;
extern struct static_key base_old_false_key;
extern struct static_key base_inv_old_false_key;
/* new api */
extern struct static_key_true base_true_key;
extern struct static_key_true base_inv_true_key;
extern struct static_key_false base_false_key;
extern struct static_key_false base_inv_false_key;
struct test_branch {
bool init_state;
struct static_key *key;
bool (*test_key)(void);
};
#define test_key_func(key, branch) \
({bool func(void) { return branch(key); } func; })
static void invert_key(struct static_key *key)
{
if (static_key_enabled(key))
static_key_disable(key);
else
static_key_enable(key);
}
static void invert_keys(struct test_branch *branches, int size)
{
struct static_key *previous = NULL;
int i;
for (i = 0; i < size; i++) {
if (previous != branches[i].key) {
invert_key(branches[i].key);
previous = branches[i].key;
}
}
}
int verify_branches(struct test_branch *branches, int size, bool invert)
{
int i;
bool ret, init;
for (i = 0; i < size; i++) {
ret = static_key_enabled(branches[i].key);
init = branches[i].init_state;
if (ret != (invert ? !init : init))
return -EINVAL;
ret = branches[i].test_key();
if (static_key_enabled(branches[i].key)) {
if (!ret)
return -EINVAL;
} else {
if (ret)
return -EINVAL;
}
}
return 0;
}
static int __init test_jump_label_init(void)
{
int ret;
int size;
struct test_branch jump_label_tests[] = {
/* internal keys - old keys */
{
.init_state = true,
.key = &old_true_key,
.test_key = test_key_func(&old_true_key, static_key_true),
},
{
.init_state = false,
.key = &old_false_key,
.test_key = test_key_func(&old_false_key, static_key_false),
},
/* internal keys - new keys */
{
.init_state = true,
.key = &true_key.key,
.test_key = test_key_func(&true_key, static_branch_likely),
},
{
.init_state = true,
.key = &true_key.key,
.test_key = test_key_func(&true_key, static_branch_unlikely),
},
{
.init_state = false,
.key = &false_key.key,
.test_key = test_key_func(&false_key, static_branch_likely),
},
{
.init_state = false,
.key = &false_key.key,
.test_key = test_key_func(&false_key, static_branch_unlikely),
},
/* external keys - old keys */
{
.init_state = true,
.key = &base_old_true_key,
.test_key = test_key_func(&base_old_true_key, static_key_true),
},
{
.init_state = false,
.key = &base_inv_old_true_key,
.test_key = test_key_func(&base_inv_old_true_key, static_key_true),
},
{
.init_state = false,
.key = &base_old_false_key,
.test_key = test_key_func(&base_old_false_key, static_key_false),
},
{
.init_state = true,
.key = &base_inv_old_false_key,
.test_key = test_key_func(&base_inv_old_false_key, static_key_false),
},
/* external keys - new keys */
{
.init_state = true,
.key = &base_true_key.key,
.test_key = test_key_func(&base_true_key, static_branch_likely),
},
{
.init_state = true,
.key = &base_true_key.key,
.test_key = test_key_func(&base_true_key, static_branch_unlikely),
},
{
.init_state = false,
.key = &base_inv_true_key.key,
.test_key = test_key_func(&base_inv_true_key, static_branch_likely),
},
{
.init_state = false,
.key = &base_inv_true_key.key,
.test_key = test_key_func(&base_inv_true_key, static_branch_unlikely),
},
{
.init_state = false,
.key = &base_false_key.key,
.test_key = test_key_func(&base_false_key, static_branch_likely),
},
{
.init_state = false,
.key = &base_false_key.key,
.test_key = test_key_func(&base_false_key, static_branch_unlikely),
},
{
.init_state = true,
.key = &base_inv_false_key.key,
.test_key = test_key_func(&base_inv_false_key, static_branch_likely),
},
{
.init_state = true,
.key = &base_inv_false_key.key,
.test_key = test_key_func(&base_inv_false_key, static_branch_unlikely),
},
};
size = ARRAY_SIZE(jump_label_tests);
ret = verify_branches(jump_label_tests, size, false);
if (ret)
goto out;
invert_keys(jump_label_tests, size);
ret = verify_branches(jump_label_tests, size, true);
if (ret)
goto out;
invert_keys(jump_label_tests, size);
ret = verify_branches(jump_label_tests, size, false);
if (ret)
goto out;
return 0;
out:
return ret;
}
static void __exit test_jump_label_exit(void)
{
}
module_init(test_jump_label_init);
module_exit(test_jump_label_exit);
MODULE_AUTHOR("Jason Baron <jbaron@akamai.com>");
MODULE_LICENSE("GPL");
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