1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Kernel module for testing static keys.
  4 *
  5 * Copyright 2015 Akamai Technologies Inc. All Rights Reserved
  6 *
  7 * Authors:
  8 *      Jason Baron       <jbaron@akamai.com>
  9 */
 10
 11#include <linux/module.h>
 12#include <linux/jump_label.h>
 13
 14/* old keys */
 15struct static_key old_true_key	= STATIC_KEY_INIT_TRUE;
 16struct static_key old_false_key	= STATIC_KEY_INIT_FALSE;
 17
 18/* new api */
 19DEFINE_STATIC_KEY_TRUE(true_key);
 20DEFINE_STATIC_KEY_FALSE(false_key);
 21
 22/* external */
 23extern struct static_key base_old_true_key;
 24extern struct static_key base_inv_old_true_key;
 25extern struct static_key base_old_false_key;
 26extern struct static_key base_inv_old_false_key;
 27
 28/* new api */
 29extern struct static_key_true base_true_key;
 30extern struct static_key_true base_inv_true_key;
 31extern struct static_key_false base_false_key;
 32extern struct static_key_false base_inv_false_key;
 33
 34
 35struct test_key {
 36	bool			init_state;
 37	struct static_key	*key;
 38	bool			(*test_key)(void);
 39};
 40
 41#define test_key_func(key, branch)	\
 42static bool key ## _ ## branch(void)	\
 43{					\
 44	return branch(&key);		\
 45}
 46
 47static void invert_key(struct static_key *key)
 48{
 49	if (static_key_enabled(key))
 50		static_key_disable(key);
 51	else
 52		static_key_enable(key);
 53}
 54
 55static void invert_keys(struct test_key *keys, int size)
 56{
 57	struct static_key *previous = NULL;
 58	int i;
 59
 60	for (i = 0; i < size; i++) {
 61		if (previous != keys[i].key) {
 62			invert_key(keys[i].key);
 63			previous = keys[i].key;
 64		}
 65	}
 66}
 67
 68static int verify_keys(struct test_key *keys, int size, bool invert)
 69{
 70	int i;
 71	bool ret, init;
 72
 73	for (i = 0; i < size; i++) {
 74		ret = static_key_enabled(keys[i].key);
 75		init = keys[i].init_state;
 76		if (ret != (invert ? !init : init))
 77			return -EINVAL;
 78		ret = keys[i].test_key();
 79		if (static_key_enabled(keys[i].key)) {
 80			if (!ret)
 81				return -EINVAL;
 82		} else {
 83			if (ret)
 84				return -EINVAL;
 85		}
 86	}
 87	return 0;
 88}
 89
 90test_key_func(old_true_key, static_key_true)
 91test_key_func(old_false_key, static_key_false)
 92test_key_func(true_key, static_branch_likely)
 93test_key_func(true_key, static_branch_unlikely)
 94test_key_func(false_key, static_branch_likely)
 95test_key_func(false_key, static_branch_unlikely)
 96test_key_func(base_old_true_key, static_key_true)
 97test_key_func(base_inv_old_true_key, static_key_true)
 98test_key_func(base_old_false_key, static_key_false)
 99test_key_func(base_inv_old_false_key, static_key_false)
100test_key_func(base_true_key, static_branch_likely)
101test_key_func(base_true_key, static_branch_unlikely)
102test_key_func(base_inv_true_key, static_branch_likely)
103test_key_func(base_inv_true_key, static_branch_unlikely)
104test_key_func(base_false_key, static_branch_likely)
105test_key_func(base_false_key, static_branch_unlikely)
106test_key_func(base_inv_false_key, static_branch_likely)
107test_key_func(base_inv_false_key, static_branch_unlikely)
108
109static int __init test_static_key_init(void)
110{
111	int ret;
112	int size;
113
114	struct test_key static_key_tests[] = {
115		/* internal keys - old keys */
116		{
117			.init_state	= true,
118			.key		= &old_true_key,
119			.test_key	= &old_true_key_static_key_true,
120		},
121		{
122			.init_state	= false,
123			.key		= &old_false_key,
124			.test_key	= &old_false_key_static_key_false,
125		},
126		/* internal keys - new keys */
127		{
128			.init_state	= true,
129			.key		= &true_key.key,
130			.test_key	= &true_key_static_branch_likely,
131		},
132		{
133			.init_state	= true,
134			.key		= &true_key.key,
135			.test_key	= &true_key_static_branch_unlikely,
136		},
137		{
138			.init_state	= false,
139			.key		= &false_key.key,
140			.test_key	= &false_key_static_branch_likely,
141		},
142		{
143			.init_state	= false,
144			.key		= &false_key.key,
145			.test_key	= &false_key_static_branch_unlikely,
146		},
147		/* external keys - old keys */
148		{
149			.init_state	= true,
150			.key		= &base_old_true_key,
151			.test_key	= &base_old_true_key_static_key_true,
152		},
153		{
154			.init_state	= false,
155			.key		= &base_inv_old_true_key,
156			.test_key	= &base_inv_old_true_key_static_key_true,
157		},
158		{
159			.init_state	= false,
160			.key		= &base_old_false_key,
161			.test_key	= &base_old_false_key_static_key_false,
162		},
163		{
164			.init_state	= true,
165			.key		= &base_inv_old_false_key,
166			.test_key	= &base_inv_old_false_key_static_key_false,
167		},
168		/* external keys - new keys */
169		{
170			.init_state	= true,
171			.key		= &base_true_key.key,
172			.test_key	= &base_true_key_static_branch_likely,
173		},
174		{
175			.init_state	= true,
176			.key		= &base_true_key.key,
177			.test_key	= &base_true_key_static_branch_unlikely,
178		},
179		{
180			.init_state	= false,
181			.key		= &base_inv_true_key.key,
182			.test_key	= &base_inv_true_key_static_branch_likely,
183		},
184		{
185			.init_state	= false,
186			.key		= &base_inv_true_key.key,
187			.test_key	= &base_inv_true_key_static_branch_unlikely,
188		},
189		{
190			.init_state	= false,
191			.key		= &base_false_key.key,
192			.test_key	= &base_false_key_static_branch_likely,
193		},
194		{
195			.init_state	= false,
196			.key		= &base_false_key.key,
197			.test_key	= &base_false_key_static_branch_unlikely,
198		},
199		{
200			.init_state	= true,
201			.key		= &base_inv_false_key.key,
202			.test_key	= &base_inv_false_key_static_branch_likely,
203		},
204		{
205			.init_state	= true,
206			.key		= &base_inv_false_key.key,
207			.test_key	= &base_inv_false_key_static_branch_unlikely,
208		},
209	};
210
211	size = ARRAY_SIZE(static_key_tests);
212
213	ret = verify_keys(static_key_tests, size, false);
214	if (ret)
215		goto out;
216
217	invert_keys(static_key_tests, size);
218	ret = verify_keys(static_key_tests, size, true);
219	if (ret)
220		goto out;
221
222	invert_keys(static_key_tests, size);
223	ret = verify_keys(static_key_tests, size, false);
224	if (ret)
225		goto out;
226	return 0;
227out:
228	return ret;
229}
230
231static void __exit test_static_key_exit(void)
232{
233}
234
235module_init(test_static_key_init);
236module_exit(test_static_key_exit);
237
238MODULE_AUTHOR("Jason Baron <jbaron@akamai.com>");
239MODULE_LICENSE("GPL");