projects/linux·blob v6.1 · refs

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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * jump label support
4 *
5 * Copyright (C) 2009 Jason Baron <[email protected]>
6 * Copyright (C) 2011 Peter Zijlstra
7 *
8 */
9#include <linux/memory.h>
10#include <linux/uaccess.h>
11#include <linux/module.h>
12#include <linux/list.h>
13#include <linux/slab.h>
14#include <linux/sort.h>
15#include <linux/err.h>
16#include <linux/static_key.h>
17#include <linux/jump_label_ratelimit.h>
18#include <linux/bug.h>
19#include <linux/cpu.h>
20#include <asm/sections.h>
21
22/* mutex to protect coming/going of the jump_label table */
23static DEFINE_MUTEX(jump_label_mutex);
24
25void jump_label_lock(void)
26{
27 mutex_lock(&jump_label_mutex);
28}
29
30void jump_label_unlock(void)
31{
32 mutex_unlock(&jump_label_mutex);
33}
34
35static int jump_label_cmp(const void *a, const void *b)
36{
37 const struct jump_entry *jea = a;
38 const struct jump_entry *jeb = b;
39
40 /*
41 * Entrires are sorted by key.
42 */
43 if (jump_entry_key(jea) < jump_entry_key(jeb))
44 return -1;
45
46 if (jump_entry_key(jea) > jump_entry_key(jeb))
47 return 1;
48
49 /*
50 * In the batching mode, entries should also be sorted by the code
51 * inside the already sorted list of entries, enabling a bsearch in
52 * the vector.
53 */
54 if (jump_entry_code(jea) < jump_entry_code(jeb))
55 return -1;
56
57 if (jump_entry_code(jea) > jump_entry_code(jeb))
58 return 1;
59
60 return 0;
61}
62
63static void jump_label_swap(void *a, void *b, int size)
64{
65 long delta = (unsigned long)a - (unsigned long)b;
66 struct jump_entry *jea = a;
67 struct jump_entry *jeb = b;
68 struct jump_entry tmp = *jea;
69
70 jea->code = jeb->code - delta;
71 jea->target = jeb->target - delta;
72 jea->key = jeb->key - delta;
73
74 jeb->code = tmp.code + delta;
75 jeb->target = tmp.target + delta;
76 jeb->key = tmp.key + delta;
77}
78
79static void
80jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
81{
82 unsigned long size;
83 void *swapfn = NULL;
84
85 if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE))
86 swapfn = jump_label_swap;
87
88 size = (((unsigned long)stop - (unsigned long)start)
89 / sizeof(struct jump_entry));
90 sort(start, size, sizeof(struct jump_entry), jump_label_cmp, swapfn);
91}
92
93static void jump_label_update(struct static_key *key);
94
95/*
96 * There are similar definitions for the !CONFIG_JUMP_LABEL case in jump_label.h.
97 * The use of 'atomic_read()' requires atomic.h and its problematic for some
98 * kernel headers such as kernel.h and others. Since static_key_count() is not
99 * used in the branch statements as it is for the !CONFIG_JUMP_LABEL case its ok
100 * to have it be a function here. Similarly, for 'static_key_enable()' and
101 * 'static_key_disable()', which require bug.h. This should allow jump_label.h
102 * to be included from most/all places for CONFIG_JUMP_LABEL.
103 */
104int static_key_count(struct static_key *key)
105{
106 /*
107 * -1 means the first static_key_slow_inc() is in progress.
108 * static_key_enabled() must return true, so return 1 here.
109 */
110 int n = atomic_read(&key->enabled);
111
112 return n >= 0 ? n : 1;
113}
114EXPORT_SYMBOL_GPL(static_key_count);
115
116void static_key_slow_inc_cpuslocked(struct static_key *key)
117{
118 int v, v1;
119
120 STATIC_KEY_CHECK_USE(key);
121 lockdep_assert_cpus_held();
122
123 /*
124 * Careful if we get concurrent static_key_slow_inc() calls;
125 * later calls must wait for the first one to _finish_ the
126 * jump_label_update() process. At the same time, however,
127 * the jump_label_update() call below wants to see
128 * static_key_enabled(&key) for jumps to be updated properly.
129 *
130 * So give a special meaning to negative key->enabled: it sends
131 * static_key_slow_inc() down the slow path, and it is non-zero
132 * so it counts as "enabled" in jump_label_update(). Note that
133 * atomic_inc_unless_negative() checks >= 0, so roll our own.
134 */
135 for (v = atomic_read(&key->enabled); v > 0; v = v1) {
136 v1 = atomic_cmpxchg(&key->enabled, v, v + 1);
137 if (likely(v1 == v))
138 return;
139 }
140
141 jump_label_lock();
142 if (atomic_read(&key->enabled) == 0) {
143 atomic_set(&key->enabled, -1);
144 jump_label_update(key);
145 /*
146 * Ensure that if the above cmpxchg loop observes our positive
147 * value, it must also observe all the text changes.
148 */
149 atomic_set_release(&key->enabled, 1);
150 } else {
151 atomic_inc(&key->enabled);
152 }
153 jump_label_unlock();
154}
155
156void static_key_slow_inc(struct static_key *key)
157{
158 cpus_read_lock();
159 static_key_slow_inc_cpuslocked(key);
160 cpus_read_unlock();
161}
162EXPORT_SYMBOL_GPL(static_key_slow_inc);
163
164void static_key_enable_cpuslocked(struct static_key *key)
165{
166 STATIC_KEY_CHECK_USE(key);
167 lockdep_assert_cpus_held();
168
169 if (atomic_read(&key->enabled) > 0) {
170 WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
171 return;
172 }
173
174 jump_label_lock();
175 if (atomic_read(&key->enabled) == 0) {
176 atomic_set(&key->enabled, -1);
177 jump_label_update(key);
178 /*
179 * See static_key_slow_inc().
180 */
181 atomic_set_release(&key->enabled, 1);
182 }
183 jump_label_unlock();
184}
185EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked);
186
187void static_key_enable(struct static_key *key)
188{
189 cpus_read_lock();
190 static_key_enable_cpuslocked(key);
191 cpus_read_unlock();
192}
193EXPORT_SYMBOL_GPL(static_key_enable);
194
195void static_key_disable_cpuslocked(struct static_key *key)
196{
197 STATIC_KEY_CHECK_USE(key);
198 lockdep_assert_cpus_held();
199
200 if (atomic_read(&key->enabled) != 1) {
201 WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
202 return;
203 }
204
205 jump_label_lock();
206 if (atomic_cmpxchg(&key->enabled, 1, 0))
207 jump_label_update(key);
208 jump_label_unlock();
209}
210EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked);
211
212void static_key_disable(struct static_key *key)
213{
214 cpus_read_lock();
215 static_key_disable_cpuslocked(key);
216 cpus_read_unlock();
217}
218EXPORT_SYMBOL_GPL(static_key_disable);
219
220static bool static_key_slow_try_dec(struct static_key *key)
221{
222 int val;
223
224 val = atomic_fetch_add_unless(&key->enabled, -1, 1);
225 if (val == 1)
226 return false;
227
228 /*
229 * The negative count check is valid even when a negative
230 * key->enabled is in use by static_key_slow_inc(); a
231 * __static_key_slow_dec() before the first static_key_slow_inc()
232 * returns is unbalanced, because all other static_key_slow_inc()
233 * instances block while the update is in progress.
234 */
235 WARN(val < 0, "jump label: negative count!\n");
236 return true;
237}
238
239static void __static_key_slow_dec_cpuslocked(struct static_key *key)
240{
241 lockdep_assert_cpus_held();
242
243 if (static_key_slow_try_dec(key))
244 return;
245
246 jump_label_lock();
247 if (atomic_dec_and_test(&key->enabled))
248 jump_label_update(key);
249 jump_label_unlock();
250}
251
252static void __static_key_slow_dec(struct static_key *key)
253{
254 cpus_read_lock();
255 __static_key_slow_dec_cpuslocked(key);
256 cpus_read_unlock();
257}
258
259void jump_label_update_timeout(struct work_struct *work)
260{
261 struct static_key_deferred *key =
262 container_of(work, struct static_key_deferred, work.work);
263 __static_key_slow_dec(&key->key);
264}
265EXPORT_SYMBOL_GPL(jump_label_update_timeout);
266
267void static_key_slow_dec(struct static_key *key)
268{
269 STATIC_KEY_CHECK_USE(key);
270 __static_key_slow_dec(key);
271}
272EXPORT_SYMBOL_GPL(static_key_slow_dec);
273
274void static_key_slow_dec_cpuslocked(struct static_key *key)
275{
276 STATIC_KEY_CHECK_USE(key);
277 __static_key_slow_dec_cpuslocked(key);
278}
279
280void __static_key_slow_dec_deferred(struct static_key *key,
281 struct delayed_work *work,
282 unsigned long timeout)
283{
284 STATIC_KEY_CHECK_USE(key);
285
286 if (static_key_slow_try_dec(key))
287 return;
288
289 schedule_delayed_work(work, timeout);
290}
291EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred);
292
293void __static_key_deferred_flush(void *key, struct delayed_work *work)
294{
295 STATIC_KEY_CHECK_USE(key);
296 flush_delayed_work(work);
297}
298EXPORT_SYMBOL_GPL(__static_key_deferred_flush);
299
300void jump_label_rate_limit(struct static_key_deferred *key,
301 unsigned long rl)
302{
303 STATIC_KEY_CHECK_USE(key);
304 key->timeout = rl;
305 INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
306}
307EXPORT_SYMBOL_GPL(jump_label_rate_limit);
308
309static int addr_conflict(struct jump_entry *entry, void *start, void *end)
310{
311 if (jump_entry_code(entry) <= (unsigned long)end &&
312 jump_entry_code(entry) + jump_entry_size(entry) > (unsigned long)start)
313 return 1;
314
315 return 0;
316}
317
318static int __jump_label_text_reserved(struct jump_entry *iter_start,
319 struct jump_entry *iter_stop, void *start, void *end, bool init)
320{
321 struct jump_entry *iter;
322
323 iter = iter_start;
324 while (iter < iter_stop) {
325 if (init || !jump_entry_is_init(iter)) {
326 if (addr_conflict(iter, start, end))
327 return 1;
328 }
329 iter++;
330 }
331
332 return 0;
333}
334
335#ifndef arch_jump_label_transform_static
336static void arch_jump_label_transform_static(struct jump_entry *entry,
337 enum jump_label_type type)
338{
339 /* nothing to do on most architectures */
340}
341#endif
342
343static inline struct jump_entry *static_key_entries(struct static_key *key)
344{
345 WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED);
346 return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);
347}
348
349static inline bool static_key_type(struct static_key *key)
350{
351 return key->type & JUMP_TYPE_TRUE;
352}
353
354static inline bool static_key_linked(struct static_key *key)
355{
356 return key->type & JUMP_TYPE_LINKED;
357}
358
359static inline void static_key_clear_linked(struct static_key *key)
360{
361 key->type &= ~JUMP_TYPE_LINKED;
362}
363
364static inline void static_key_set_linked(struct static_key *key)
365{
366 key->type |= JUMP_TYPE_LINKED;
367}
368
369/***
370 * A 'struct static_key' uses a union such that it either points directly
371 * to a table of 'struct jump_entry' or to a linked list of modules which in
372 * turn point to 'struct jump_entry' tables.
373 *
374 * The two lower bits of the pointer are used to keep track of which pointer
375 * type is in use and to store the initial branch direction, we use an access
376 * function which preserves these bits.
377 */
378static void static_key_set_entries(struct static_key *key,
379 struct jump_entry *entries)
380{
381 unsigned long type;
382
383 WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK);
384 type = key->type & JUMP_TYPE_MASK;
385 key->entries = entries;
386 key->type |= type;
387}
388
389static enum jump_label_type jump_label_type(struct jump_entry *entry)
390{
391 struct static_key *key = jump_entry_key(entry);
392 bool enabled = static_key_enabled(key);
393 bool branch = jump_entry_is_branch(entry);
394
395 /* See the comment in linux/jump_label.h */
396 return enabled ^ branch;
397}
398
399static bool jump_label_can_update(struct jump_entry *entry, bool init)
400{
401 /*
402 * Cannot update code that was in an init text area.
403 */
404 if (!init && jump_entry_is_init(entry))
405 return false;
406
407 if (!kernel_text_address(jump_entry_code(entry))) {
408 /*
409 * This skips patching built-in __exit, which
410 * is part of init_section_contains() but is
411 * not part of kernel_text_address().
412 *
413 * Skipping built-in __exit is fine since it
414 * will never be executed.
415 */
416 WARN_ONCE(!jump_entry_is_init(entry),
417 "can't patch jump_label at %pS",
418 (void *)jump_entry_code(entry));
419 return false;
420 }
421
422 return true;
423}
424
425#ifndef HAVE_JUMP_LABEL_BATCH
426static void __jump_label_update(struct static_key *key,
427 struct jump_entry *entry,
428 struct jump_entry *stop,
429 bool init)
430{
431 for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
432 if (jump_label_can_update(entry, init))
433 arch_jump_label_transform(entry, jump_label_type(entry));
434 }
435}
436#else
437static void __jump_label_update(struct static_key *key,
438 struct jump_entry *entry,
439 struct jump_entry *stop,
440 bool init)
441{
442 for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
443
444 if (!jump_label_can_update(entry, init))
445 continue;
446
447 if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) {
448 /*
449 * Queue is full: Apply the current queue and try again.
450 */
451 arch_jump_label_transform_apply();
452 BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry)));
453 }
454 }
455 arch_jump_label_transform_apply();
456}
457#endif
458
459void __init jump_label_init(void)
460{
461 struct jump_entry *iter_start = __start___jump_table;
462 struct jump_entry *iter_stop = __stop___jump_table;
463 struct static_key *key = NULL;
464 struct jump_entry *iter;
465
466 /*
467 * Since we are initializing the static_key.enabled field with
468 * with the 'raw' int values (to avoid pulling in atomic.h) in
469 * jump_label.h, let's make sure that is safe. There are only two
470 * cases to check since we initialize to 0 or 1.
471 */
472 BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0);
473 BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1);
474
475 if (static_key_initialized)
476 return;
477
478 cpus_read_lock();
479 jump_label_lock();
480 jump_label_sort_entries(iter_start, iter_stop);
481
482 for (iter = iter_start; iter < iter_stop; iter++) {
483 struct static_key *iterk;
484 bool in_init;
485
486 /* rewrite NOPs */
487 if (jump_label_type(iter) == JUMP_LABEL_NOP)
488 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
489
490 in_init = init_section_contains((void *)jump_entry_code(iter), 1);
491 jump_entry_set_init(iter, in_init);
492
493 iterk = jump_entry_key(iter);
494 if (iterk == key)
495 continue;
496
497 key = iterk;
498 static_key_set_entries(key, iter);
499 }
500 static_key_initialized = true;
501 jump_label_unlock();
502 cpus_read_unlock();
503}
504
505#ifdef CONFIG_MODULES
506
507enum jump_label_type jump_label_init_type(struct jump_entry *entry)
508{
509 struct static_key *key = jump_entry_key(entry);
510 bool type = static_key_type(key);
511 bool branch = jump_entry_is_branch(entry);
512
513 /* See the comment in linux/jump_label.h */
514 return type ^ branch;
515}
516
517struct static_key_mod {
518 struct static_key_mod *next;
519 struct jump_entry *entries;
520 struct module *mod;
521};
522
523static inline struct static_key_mod *static_key_mod(struct static_key *key)
524{
525 WARN_ON_ONCE(!static_key_linked(key));
526 return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK);
527}
528
529/***
530 * key->type and key->next are the same via union.
531 * This sets key->next and preserves the type bits.
532 *
533 * See additional comments above static_key_set_entries().
534 */
535static void static_key_set_mod(struct static_key *key,
536 struct static_key_mod *mod)
537{
538 unsigned long type;
539
540 WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK);
541 type = key->type & JUMP_TYPE_MASK;
542 key->next = mod;
543 key->type |= type;
544}
545
546static int __jump_label_mod_text_reserved(void *start, void *end)
547{
548 struct module *mod;
549 int ret;
550
551 preempt_disable();
552 mod = __module_text_address((unsigned long)start);
553 WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
554 if (!try_module_get(mod))
555 mod = NULL;
556 preempt_enable();
557
558 if (!mod)
559 return 0;
560
561 ret = __jump_label_text_reserved(mod->jump_entries,
562 mod->jump_entries + mod->num_jump_entries,
563 start, end, mod->state == MODULE_STATE_COMING);
564
565 module_put(mod);
566
567 return ret;
568}
569
570static void __jump_label_mod_update(struct static_key *key)
571{
572 struct static_key_mod *mod;
573
574 for (mod = static_key_mod(key); mod; mod = mod->next) {
575 struct jump_entry *stop;
576 struct module *m;
577
578 /*
579 * NULL if the static_key is defined in a module
580 * that does not use it
581 */
582 if (!mod->entries)
583 continue;
584
585 m = mod->mod;
586 if (!m)
587 stop = __stop___jump_table;
588 else
589 stop = m->jump_entries + m->num_jump_entries;
590 __jump_label_update(key, mod->entries, stop,
591 m && m->state == MODULE_STATE_COMING);
592 }
593}
594
595static int jump_label_add_module(struct module *mod)
596{
597 struct jump_entry *iter_start = mod->jump_entries;
598 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
599 struct jump_entry *iter;
600 struct static_key *key = NULL;
601 struct static_key_mod *jlm, *jlm2;
602
603 /* if the module doesn't have jump label entries, just return */
604 if (iter_start == iter_stop)
605 return 0;
606
607 jump_label_sort_entries(iter_start, iter_stop);
608
609 for (iter = iter_start; iter < iter_stop; iter++) {
610 struct static_key *iterk;
611 bool in_init;
612
613 in_init = within_module_init(jump_entry_code(iter), mod);
614 jump_entry_set_init(iter, in_init);
615
616 iterk = jump_entry_key(iter);
617 if (iterk == key)
618 continue;
619
620 key = iterk;
621 if (within_module((unsigned long)key, mod)) {
622 static_key_set_entries(key, iter);
623 continue;
624 }
625 jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
626 if (!jlm)
627 return -ENOMEM;
628 if (!static_key_linked(key)) {
629 jlm2 = kzalloc(sizeof(struct static_key_mod),
630 GFP_KERNEL);
631 if (!jlm2) {
632 kfree(jlm);
633 return -ENOMEM;
634 }
635 preempt_disable();
636 jlm2->mod = __module_address((unsigned long)key);
637 preempt_enable();
638 jlm2->entries = static_key_entries(key);
639 jlm2->next = NULL;
640 static_key_set_mod(key, jlm2);
641 static_key_set_linked(key);
642 }
643 jlm->mod = mod;
644 jlm->entries = iter;
645 jlm->next = static_key_mod(key);
646 static_key_set_mod(key, jlm);
647 static_key_set_linked(key);
648
649 /* Only update if we've changed from our initial state */
650 if (jump_label_type(iter) != jump_label_init_type(iter))
651 __jump_label_update(key, iter, iter_stop, true);
652 }
653
654 return 0;
655}
656
657static void jump_label_del_module(struct module *mod)
658{
659 struct jump_entry *iter_start = mod->jump_entries;
660 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
661 struct jump_entry *iter;
662 struct static_key *key = NULL;
663 struct static_key_mod *jlm, **prev;
664
665 for (iter = iter_start; iter < iter_stop; iter++) {
666 if (jump_entry_key(iter) == key)
667 continue;
668
669 key = jump_entry_key(iter);
670
671 if (within_module((unsigned long)key, mod))
672 continue;
673
674 /* No memory during module load */
675 if (WARN_ON(!static_key_linked(key)))
676 continue;
677
678 prev = &key->next;
679 jlm = static_key_mod(key);
680
681 while (jlm && jlm->mod != mod) {
682 prev = &jlm->next;
683 jlm = jlm->next;
684 }
685
686 /* No memory during module load */
687 if (WARN_ON(!jlm))
688 continue;
689
690 if (prev == &key->next)
691 static_key_set_mod(key, jlm->next);
692 else
693 *prev = jlm->next;
694
695 kfree(jlm);
696
697 jlm = static_key_mod(key);
698 /* if only one etry is left, fold it back into the static_key */
699 if (jlm->next == NULL) {
700 static_key_set_entries(key, jlm->entries);
701 static_key_clear_linked(key);
702 kfree(jlm);
703 }
704 }
705}
706
707static int
708jump_label_module_notify(struct notifier_block *self, unsigned long val,
709 void *data)
710{
711 struct module *mod = data;
712 int ret = 0;
713
714 cpus_read_lock();
715 jump_label_lock();
716
717 switch (val) {
718 case MODULE_STATE_COMING:
719 ret = jump_label_add_module(mod);
720 if (ret) {
721 WARN(1, "Failed to allocate memory: jump_label may not work properly.\n");
722 jump_label_del_module(mod);
723 }
724 break;
725 case MODULE_STATE_GOING:
726 jump_label_del_module(mod);
727 break;
728 }
729
730 jump_label_unlock();
731 cpus_read_unlock();
732
733 return notifier_from_errno(ret);
734}
735
736static struct notifier_block jump_label_module_nb = {
737 .notifier_call = jump_label_module_notify,
738 .priority = 1, /* higher than tracepoints */
739};
740
741static __init int jump_label_init_module(void)
742{
743 return register_module_notifier(&jump_label_module_nb);
744}
745early_initcall(jump_label_init_module);
746
747#endif /* CONFIG_MODULES */
748
749/***
750 * jump_label_text_reserved - check if addr range is reserved
751 * @start: start text addr
752 * @end: end text addr
753 *
754 * checks if the text addr located between @start and @end
755 * overlaps with any of the jump label patch addresses. Code
756 * that wants to modify kernel text should first verify that
757 * it does not overlap with any of the jump label addresses.
758 * Caller must hold jump_label_mutex.
759 *
760 * returns 1 if there is an overlap, 0 otherwise
761 */
762int jump_label_text_reserved(void *start, void *end)
763{
764 bool init = system_state < SYSTEM_RUNNING;
765 int ret = __jump_label_text_reserved(__start___jump_table,
766 __stop___jump_table, start, end, init);
767
768 if (ret)
769 return ret;
770
771#ifdef CONFIG_MODULES
772 ret = __jump_label_mod_text_reserved(start, end);
773#endif
774 return ret;
775}
776
777static void jump_label_update(struct static_key *key)
778{
779 struct jump_entry *stop = __stop___jump_table;
780 bool init = system_state < SYSTEM_RUNNING;
781 struct jump_entry *entry;
782#ifdef CONFIG_MODULES
783 struct module *mod;
784
785 if (static_key_linked(key)) {
786 __jump_label_mod_update(key);
787 return;
788 }
789
790 preempt_disable();
791 mod = __module_address((unsigned long)key);
792 if (mod) {
793 stop = mod->jump_entries + mod->num_jump_entries;
794 init = mod->state == MODULE_STATE_COMING;
795 }
796 preempt_enable();
797#endif
798 entry = static_key_entries(key);
799 /* if there are no users, entry can be NULL */
800 if (entry)
801 __jump_label_update(key, entry, stop, init);
802}
803
804#ifdef CONFIG_STATIC_KEYS_SELFTEST
805static DEFINE_STATIC_KEY_TRUE(sk_true);
806static DEFINE_STATIC_KEY_FALSE(sk_false);
807
808static __init int jump_label_test(void)
809{
810 int i;
811
812 for (i = 0; i < 2; i++) {
813 WARN_ON(static_key_enabled(&sk_true.key) != true);
814 WARN_ON(static_key_enabled(&sk_false.key) != false);
815
816 WARN_ON(!static_branch_likely(&sk_true));
817 WARN_ON(!static_branch_unlikely(&sk_true));
818 WARN_ON(static_branch_likely(&sk_false));
819 WARN_ON(static_branch_unlikely(&sk_false));
820
821 static_branch_disable(&sk_true);
822 static_branch_enable(&sk_false);
823
824 WARN_ON(static_key_enabled(&sk_true.key) == true);
825 WARN_ON(static_key_enabled(&sk_false.key) == false);
826
827 WARN_ON(static_branch_likely(&sk_true));
828 WARN_ON(static_branch_unlikely(&sk_true));
829 WARN_ON(!static_branch_likely(&sk_false));
830 WARN_ON(!static_branch_unlikely(&sk_false));
831
832 static_branch_enable(&sk_true);
833 static_branch_disable(&sk_false);
834 }
835
836 return 0;
837}
838early_initcall(jump_label_test);
839#endif /* STATIC_KEYS_SELFTEST */