1/*
2 * jump label support
3 *
4 * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
5 * Copyright (C) 2011 Peter Zijlstra
6 *
7 */
8#include <linux/memory.h>
9#include <linux/uaccess.h>
10#include <linux/module.h>
11#include <linux/list.h>
12#include <linux/slab.h>
13#include <linux/sort.h>
14#include <linux/err.h>
15#include <linux/static_key.h>
16#include <linux/jump_label_ratelimit.h>
17#include <linux/bug.h>
18#include <linux/cpu.h>
19#include <asm/sections.h>
20
21/* mutex to protect coming/going of the the jump_label table */
22static DEFINE_MUTEX(jump_label_mutex);
23
24void jump_label_lock(void)
25{
26 mutex_lock(&jump_label_mutex);
27}
28
29void jump_label_unlock(void)
30{
31 mutex_unlock(&jump_label_mutex);
32}
33
34static int jump_label_cmp(const void *a, const void *b)
35{
36 const struct jump_entry *jea = a;
37 const struct jump_entry *jeb = b;
38
39 if (jump_entry_key(jea) < jump_entry_key(jeb))
40 return -1;
41
42 if (jump_entry_key(jea) > jump_entry_key(jeb))
43 return 1;
44
45 return 0;
46}
47
48static void jump_label_swap(void *a, void *b, int size)
49{
50 long delta = (unsigned long)a - (unsigned long)b;
51 struct jump_entry *jea = a;
52 struct jump_entry *jeb = b;
53 struct jump_entry tmp = *jea;
54
55 jea->code = jeb->code - delta;
56 jea->target = jeb->target - delta;
57 jea->key = jeb->key - delta;
58
59 jeb->code = tmp.code + delta;
60 jeb->target = tmp.target + delta;
61 jeb->key = tmp.key + delta;
62}
63
64static void
65jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
66{
67 unsigned long size;
68 void *swapfn = NULL;
69
70 if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE))
71 swapfn = jump_label_swap;
72
73 size = (((unsigned long)stop - (unsigned long)start)
74 / sizeof(struct jump_entry));
75 sort(start, size, sizeof(struct jump_entry), jump_label_cmp, swapfn);
76}
77
78static void jump_label_update(struct static_key *key);
79
80/*
81 * There are similar definitions for the !CONFIG_JUMP_LABEL case in jump_label.h.
82 * The use of 'atomic_read()' requires atomic.h and its problematic for some
83 * kernel headers such as kernel.h and others. Since static_key_count() is not
84 * used in the branch statements as it is for the !CONFIG_JUMP_LABEL case its ok
85 * to have it be a function here. Similarly, for 'static_key_enable()' and
86 * 'static_key_disable()', which require bug.h. This should allow jump_label.h
87 * to be included from most/all places for CONFIG_JUMP_LABEL.
88 */
89int static_key_count(struct static_key *key)
90{
91 /*
92 * -1 means the first static_key_slow_inc() is in progress.
93 * static_key_enabled() must return true, so return 1 here.
94 */
95 int n = atomic_read(&key->enabled);
96
97 return n >= 0 ? n : 1;
98}
99EXPORT_SYMBOL_GPL(static_key_count);
100
101void static_key_slow_inc_cpuslocked(struct static_key *key)
102{
103 int v, v1;
104
105 STATIC_KEY_CHECK_USE(key);
106 lockdep_assert_cpus_held();
107
108 /*
109 * Careful if we get concurrent static_key_slow_inc() calls;
110 * later calls must wait for the first one to _finish_ the
111 * jump_label_update() process. At the same time, however,
112 * the jump_label_update() call below wants to see
113 * static_key_enabled(&key) for jumps to be updated properly.
114 *
115 * So give a special meaning to negative key->enabled: it sends
116 * static_key_slow_inc() down the slow path, and it is non-zero
117 * so it counts as "enabled" in jump_label_update(). Note that
118 * atomic_inc_unless_negative() checks >= 0, so roll our own.
119 */
120 for (v = atomic_read(&key->enabled); v > 0; v = v1) {
121 v1 = atomic_cmpxchg(&key->enabled, v, v + 1);
122 if (likely(v1 == v))
123 return;
124 }
125
126 jump_label_lock();
127 if (atomic_read(&key->enabled) == 0) {
128 atomic_set(&key->enabled, -1);
129 jump_label_update(key);
130 /*
131 * Ensure that if the above cmpxchg loop observes our positive
132 * value, it must also observe all the text changes.
133 */
134 atomic_set_release(&key->enabled, 1);
135 } else {
136 atomic_inc(&key->enabled);
137 }
138 jump_label_unlock();
139}
140
141void static_key_slow_inc(struct static_key *key)
142{
143 cpus_read_lock();
144 static_key_slow_inc_cpuslocked(key);
145 cpus_read_unlock();
146}
147EXPORT_SYMBOL_GPL(static_key_slow_inc);
148
149void static_key_enable_cpuslocked(struct static_key *key)
150{
151 STATIC_KEY_CHECK_USE(key);
152 lockdep_assert_cpus_held();
153
154 if (atomic_read(&key->enabled) > 0) {
155 WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
156 return;
157 }
158
159 jump_label_lock();
160 if (atomic_read(&key->enabled) == 0) {
161 atomic_set(&key->enabled, -1);
162 jump_label_update(key);
163 /*
164 * See static_key_slow_inc().
165 */
166 atomic_set_release(&key->enabled, 1);
167 }
168 jump_label_unlock();
169}
170EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked);
171
172void static_key_enable(struct static_key *key)
173{
174 cpus_read_lock();
175 static_key_enable_cpuslocked(key);
176 cpus_read_unlock();
177}
178EXPORT_SYMBOL_GPL(static_key_enable);
179
180void static_key_disable_cpuslocked(struct static_key *key)
181{
182 STATIC_KEY_CHECK_USE(key);
183 lockdep_assert_cpus_held();
184
185 if (atomic_read(&key->enabled) != 1) {
186 WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
187 return;
188 }
189
190 jump_label_lock();
191 if (atomic_cmpxchg(&key->enabled, 1, 0))
192 jump_label_update(key);
193 jump_label_unlock();
194}
195EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked);
196
197void static_key_disable(struct static_key *key)
198{
199 cpus_read_lock();
200 static_key_disable_cpuslocked(key);
201 cpus_read_unlock();
202}
203EXPORT_SYMBOL_GPL(static_key_disable);
204
205static void __static_key_slow_dec_cpuslocked(struct static_key *key,
206 unsigned long rate_limit,
207 struct delayed_work *work)
208{
209 lockdep_assert_cpus_held();
210
211 /*
212 * The negative count check is valid even when a negative
213 * key->enabled is in use by static_key_slow_inc(); a
214 * __static_key_slow_dec() before the first static_key_slow_inc()
215 * returns is unbalanced, because all other static_key_slow_inc()
216 * instances block while the update is in progress.
217 */
218 if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
219 WARN(atomic_read(&key->enabled) < 0,
220 "jump label: negative count!\n");
221 return;
222 }
223
224 if (rate_limit) {
225 atomic_inc(&key->enabled);
226 schedule_delayed_work(work, rate_limit);
227 } else {
228 jump_label_update(key);
229 }
230 jump_label_unlock();
231}
232
233static void __static_key_slow_dec(struct static_key *key,
234 unsigned long rate_limit,
235 struct delayed_work *work)
236{
237 cpus_read_lock();
238 __static_key_slow_dec_cpuslocked(key, rate_limit, work);
239 cpus_read_unlock();
240}
241
242static void jump_label_update_timeout(struct work_struct *work)
243{
244 struct static_key_deferred *key =
245 container_of(work, struct static_key_deferred, work.work);
246 __static_key_slow_dec(&key->key, 0, NULL);
247}
248
249void static_key_slow_dec(struct static_key *key)
250{
251 STATIC_KEY_CHECK_USE(key);
252 __static_key_slow_dec(key, 0, NULL);
253}
254EXPORT_SYMBOL_GPL(static_key_slow_dec);
255
256void static_key_slow_dec_cpuslocked(struct static_key *key)
257{
258 STATIC_KEY_CHECK_USE(key);
259 __static_key_slow_dec_cpuslocked(key, 0, NULL);
260}
261
262void static_key_slow_dec_deferred(struct static_key_deferred *key)
263{
264 STATIC_KEY_CHECK_USE(key);
265 __static_key_slow_dec(&key->key, key->timeout, &key->work);
266}
267EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
268
269void static_key_deferred_flush(struct static_key_deferred *key)
270{
271 STATIC_KEY_CHECK_USE(key);
272 flush_delayed_work(&key->work);
273}
274EXPORT_SYMBOL_GPL(static_key_deferred_flush);
275
276void jump_label_rate_limit(struct static_key_deferred *key,
277 unsigned long rl)
278{
279 STATIC_KEY_CHECK_USE(key);
280 key->timeout = rl;
281 INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
282}
283EXPORT_SYMBOL_GPL(jump_label_rate_limit);
284
285static int addr_conflict(struct jump_entry *entry, void *start, void *end)
286{
287 if (jump_entry_code(entry) <= (unsigned long)end &&
288 jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
289 return 1;
290
291 return 0;
292}
293
294static int __jump_label_text_reserved(struct jump_entry *iter_start,
295 struct jump_entry *iter_stop, void *start, void *end)
296{
297 struct jump_entry *iter;
298
299 iter = iter_start;
300 while (iter < iter_stop) {
301 if (addr_conflict(iter, start, end))
302 return 1;
303 iter++;
304 }
305
306 return 0;
307}
308
309/*
310 * Update code which is definitely not currently executing.
311 * Architectures which need heavyweight synchronization to modify
312 * running code can override this to make the non-live update case
313 * cheaper.
314 */
315void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
316 enum jump_label_type type)
317{
318 arch_jump_label_transform(entry, type);
319}
320
321static inline struct jump_entry *static_key_entries(struct static_key *key)
322{
323 WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED);
324 return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);
325}
326
327static inline bool static_key_type(struct static_key *key)
328{
329 return key->type & JUMP_TYPE_TRUE;
330}
331
332static inline bool static_key_linked(struct static_key *key)
333{
334 return key->type & JUMP_TYPE_LINKED;
335}
336
337static inline void static_key_clear_linked(struct static_key *key)
338{
339 key->type &= ~JUMP_TYPE_LINKED;
340}
341
342static inline void static_key_set_linked(struct static_key *key)
343{
344 key->type |= JUMP_TYPE_LINKED;
345}
346
347/***
348 * A 'struct static_key' uses a union such that it either points directly
349 * to a table of 'struct jump_entry' or to a linked list of modules which in
350 * turn point to 'struct jump_entry' tables.
351 *
352 * The two lower bits of the pointer are used to keep track of which pointer
353 * type is in use and to store the initial branch direction, we use an access
354 * function which preserves these bits.
355 */
356static void static_key_set_entries(struct static_key *key,
357 struct jump_entry *entries)
358{
359 unsigned long type;
360
361 WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK);
362 type = key->type & JUMP_TYPE_MASK;
363 key->entries = entries;
364 key->type |= type;
365}
366
367static enum jump_label_type jump_label_type(struct jump_entry *entry)
368{
369 struct static_key *key = jump_entry_key(entry);
370 bool enabled = static_key_enabled(key);
371 bool branch = jump_entry_is_branch(entry);
372
373 /* See the comment in linux/jump_label.h */
374 return enabled ^ branch;
375}
376
377static void __jump_label_update(struct static_key *key,
378 struct jump_entry *entry,
379 struct jump_entry *stop,
380 bool init)
381{
382 for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
383 /*
384 * An entry->code of 0 indicates an entry which has been
385 * disabled because it was in an init text area.
386 */
387 if (init || !jump_entry_is_init(entry)) {
388 if (kernel_text_address(jump_entry_code(entry)))
389 arch_jump_label_transform(entry, jump_label_type(entry));
390 else
391 WARN_ONCE(1, "can't patch jump_label at %pS",
392 (void *)jump_entry_code(entry));
393 }
394 }
395}
396
397void __init jump_label_init(void)
398{
399 struct jump_entry *iter_start = __start___jump_table;
400 struct jump_entry *iter_stop = __stop___jump_table;
401 struct static_key *key = NULL;
402 struct jump_entry *iter;
403
404 /*
405 * Since we are initializing the static_key.enabled field with
406 * with the 'raw' int values (to avoid pulling in atomic.h) in
407 * jump_label.h, let's make sure that is safe. There are only two
408 * cases to check since we initialize to 0 or 1.
409 */
410 BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0);
411 BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1);
412
413 if (static_key_initialized)
414 return;
415
416 cpus_read_lock();
417 jump_label_lock();
418 jump_label_sort_entries(iter_start, iter_stop);
419
420 for (iter = iter_start; iter < iter_stop; iter++) {
421 struct static_key *iterk;
422
423 /* rewrite NOPs */
424 if (jump_label_type(iter) == JUMP_LABEL_NOP)
425 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
426
427 if (init_section_contains((void *)jump_entry_code(iter), 1))
428 jump_entry_set_init(iter);
429
430 iterk = jump_entry_key(iter);
431 if (iterk == key)
432 continue;
433
434 key = iterk;
435 static_key_set_entries(key, iter);
436 }
437 static_key_initialized = true;
438 jump_label_unlock();
439 cpus_read_unlock();
440}
441
442#ifdef CONFIG_MODULES
443
444static enum jump_label_type jump_label_init_type(struct jump_entry *entry)
445{
446 struct static_key *key = jump_entry_key(entry);
447 bool type = static_key_type(key);
448 bool branch = jump_entry_is_branch(entry);
449
450 /* See the comment in linux/jump_label.h */
451 return type ^ branch;
452}
453
454struct static_key_mod {
455 struct static_key_mod *next;
456 struct jump_entry *entries;
457 struct module *mod;
458};
459
460static inline struct static_key_mod *static_key_mod(struct static_key *key)
461{
462 WARN_ON_ONCE(!static_key_linked(key));
463 return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK);
464}
465
466/***
467 * key->type and key->next are the same via union.
468 * This sets key->next and preserves the type bits.
469 *
470 * See additional comments above static_key_set_entries().
471 */
472static void static_key_set_mod(struct static_key *key,
473 struct static_key_mod *mod)
474{
475 unsigned long type;
476
477 WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK);
478 type = key->type & JUMP_TYPE_MASK;
479 key->next = mod;
480 key->type |= type;
481}
482
483static int __jump_label_mod_text_reserved(void *start, void *end)
484{
485 struct module *mod;
486
487 preempt_disable();
488 mod = __module_text_address((unsigned long)start);
489 WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
490 preempt_enable();
491
492 if (!mod)
493 return 0;
494
495
496 return __jump_label_text_reserved(mod->jump_entries,
497 mod->jump_entries + mod->num_jump_entries,
498 start, end);
499}
500
501static void __jump_label_mod_update(struct static_key *key)
502{
503 struct static_key_mod *mod;
504
505 for (mod = static_key_mod(key); mod; mod = mod->next) {
506 struct jump_entry *stop;
507 struct module *m;
508
509 /*
510 * NULL if the static_key is defined in a module
511 * that does not use it
512 */
513 if (!mod->entries)
514 continue;
515
516 m = mod->mod;
517 if (!m)
518 stop = __stop___jump_table;
519 else
520 stop = m->jump_entries + m->num_jump_entries;
521 __jump_label_update(key, mod->entries, stop,
522 m && m->state == MODULE_STATE_COMING);
523 }
524}
525
526/***
527 * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
528 * @mod: module to patch
529 *
530 * Allow for run-time selection of the optimal nops. Before the module
531 * loads patch these with arch_get_jump_label_nop(), which is specified by
532 * the arch specific jump label code.
533 */
534void jump_label_apply_nops(struct module *mod)
535{
536 struct jump_entry *iter_start = mod->jump_entries;
537 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
538 struct jump_entry *iter;
539
540 /* if the module doesn't have jump label entries, just return */
541 if (iter_start == iter_stop)
542 return;
543
544 for (iter = iter_start; iter < iter_stop; iter++) {
545 /* Only write NOPs for arch_branch_static(). */
546 if (jump_label_init_type(iter) == JUMP_LABEL_NOP)
547 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
548 }
549}
550
551static int jump_label_add_module(struct module *mod)
552{
553 struct jump_entry *iter_start = mod->jump_entries;
554 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
555 struct jump_entry *iter;
556 struct static_key *key = NULL;
557 struct static_key_mod *jlm, *jlm2;
558
559 /* if the module doesn't have jump label entries, just return */
560 if (iter_start == iter_stop)
561 return 0;
562
563 jump_label_sort_entries(iter_start, iter_stop);
564
565 for (iter = iter_start; iter < iter_stop; iter++) {
566 struct static_key *iterk;
567
568 if (within_module_init(jump_entry_code(iter), mod))
569 jump_entry_set_init(iter);
570
571 iterk = jump_entry_key(iter);
572 if (iterk == key)
573 continue;
574
575 key = iterk;
576 if (within_module((unsigned long)key, mod)) {
577 static_key_set_entries(key, iter);
578 continue;
579 }
580 jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
581 if (!jlm)
582 return -ENOMEM;
583 if (!static_key_linked(key)) {
584 jlm2 = kzalloc(sizeof(struct static_key_mod),
585 GFP_KERNEL);
586 if (!jlm2) {
587 kfree(jlm);
588 return -ENOMEM;
589 }
590 preempt_disable();
591 jlm2->mod = __module_address((unsigned long)key);
592 preempt_enable();
593 jlm2->entries = static_key_entries(key);
594 jlm2->next = NULL;
595 static_key_set_mod(key, jlm2);
596 static_key_set_linked(key);
597 }
598 jlm->mod = mod;
599 jlm->entries = iter;
600 jlm->next = static_key_mod(key);
601 static_key_set_mod(key, jlm);
602 static_key_set_linked(key);
603
604 /* Only update if we've changed from our initial state */
605 if (jump_label_type(iter) != jump_label_init_type(iter))
606 __jump_label_update(key, iter, iter_stop, true);
607 }
608
609 return 0;
610}
611
612static void jump_label_del_module(struct module *mod)
613{
614 struct jump_entry *iter_start = mod->jump_entries;
615 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
616 struct jump_entry *iter;
617 struct static_key *key = NULL;
618 struct static_key_mod *jlm, **prev;
619
620 for (iter = iter_start; iter < iter_stop; iter++) {
621 if (jump_entry_key(iter) == key)
622 continue;
623
624 key = jump_entry_key(iter);
625
626 if (within_module((unsigned long)key, mod))
627 continue;
628
629 /* No memory during module load */
630 if (WARN_ON(!static_key_linked(key)))
631 continue;
632
633 prev = &key->next;
634 jlm = static_key_mod(key);
635
636 while (jlm && jlm->mod != mod) {
637 prev = &jlm->next;
638 jlm = jlm->next;
639 }
640
641 /* No memory during module load */
642 if (WARN_ON(!jlm))
643 continue;
644
645 if (prev == &key->next)
646 static_key_set_mod(key, jlm->next);
647 else
648 *prev = jlm->next;
649
650 kfree(jlm);
651
652 jlm = static_key_mod(key);
653 /* if only one etry is left, fold it back into the static_key */
654 if (jlm->next == NULL) {
655 static_key_set_entries(key, jlm->entries);
656 static_key_clear_linked(key);
657 kfree(jlm);
658 }
659 }
660}
661
662static int
663jump_label_module_notify(struct notifier_block *self, unsigned long val,
664 void *data)
665{
666 struct module *mod = data;
667 int ret = 0;
668
669 cpus_read_lock();
670 jump_label_lock();
671
672 switch (val) {
673 case MODULE_STATE_COMING:
674 ret = jump_label_add_module(mod);
675 if (ret) {
676 WARN(1, "Failed to allocate memory: jump_label may not work properly.\n");
677 jump_label_del_module(mod);
678 }
679 break;
680 case MODULE_STATE_GOING:
681 jump_label_del_module(mod);
682 break;
683 }
684
685 jump_label_unlock();
686 cpus_read_unlock();
687
688 return notifier_from_errno(ret);
689}
690
691static struct notifier_block jump_label_module_nb = {
692 .notifier_call = jump_label_module_notify,
693 .priority = 1, /* higher than tracepoints */
694};
695
696static __init int jump_label_init_module(void)
697{
698 return register_module_notifier(&jump_label_module_nb);
699}
700early_initcall(jump_label_init_module);
701
702#endif /* CONFIG_MODULES */
703
704/***
705 * jump_label_text_reserved - check if addr range is reserved
706 * @start: start text addr
707 * @end: end text addr
708 *
709 * checks if the text addr located between @start and @end
710 * overlaps with any of the jump label patch addresses. Code
711 * that wants to modify kernel text should first verify that
712 * it does not overlap with any of the jump label addresses.
713 * Caller must hold jump_label_mutex.
714 *
715 * returns 1 if there is an overlap, 0 otherwise
716 */
717int jump_label_text_reserved(void *start, void *end)
718{
719 int ret = __jump_label_text_reserved(__start___jump_table,
720 __stop___jump_table, start, end);
721
722 if (ret)
723 return ret;
724
725#ifdef CONFIG_MODULES
726 ret = __jump_label_mod_text_reserved(start, end);
727#endif
728 return ret;
729}
730
731static void jump_label_update(struct static_key *key)
732{
733 struct jump_entry *stop = __stop___jump_table;
734 struct jump_entry *entry;
735#ifdef CONFIG_MODULES
736 struct module *mod;
737
738 if (static_key_linked(key)) {
739 __jump_label_mod_update(key);
740 return;
741 }
742
743 preempt_disable();
744 mod = __module_address((unsigned long)key);
745 if (mod)
746 stop = mod->jump_entries + mod->num_jump_entries;
747 preempt_enable();
748#endif
749 entry = static_key_entries(key);
750 /* if there are no users, entry can be NULL */
751 if (entry)
752 __jump_label_update(key, entry, stop,
753 system_state < SYSTEM_RUNNING);
754}
755
756#ifdef CONFIG_STATIC_KEYS_SELFTEST
757static DEFINE_STATIC_KEY_TRUE(sk_true);
758static DEFINE_STATIC_KEY_FALSE(sk_false);
759
760static __init int jump_label_test(void)
761{
762 int i;
763
764 for (i = 0; i < 2; i++) {
765 WARN_ON(static_key_enabled(&sk_true.key) != true);
766 WARN_ON(static_key_enabled(&sk_false.key) != false);
767
768 WARN_ON(!static_branch_likely(&sk_true));
769 WARN_ON(!static_branch_unlikely(&sk_true));
770 WARN_ON(static_branch_likely(&sk_false));
771 WARN_ON(static_branch_unlikely(&sk_false));
772
773 static_branch_disable(&sk_true);
774 static_branch_enable(&sk_false);
775
776 WARN_ON(static_key_enabled(&sk_true.key) == true);
777 WARN_ON(static_key_enabled(&sk_false.key) == false);
778
779 WARN_ON(static_branch_likely(&sk_true));
780 WARN_ON(static_branch_unlikely(&sk_true));
781 WARN_ON(!static_branch_likely(&sk_false));
782 WARN_ON(!static_branch_unlikely(&sk_false));
783
784 static_branch_enable(&sk_true);
785 static_branch_disable(&sk_false);
786 }
787
788 return 0;
789}
790early_initcall(jump_label_test);
791#endif /* STATIC_KEYS_SELFTEST */
792