projects/linux·blob v5.13 · 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_LABEL_NOP_SIZE > (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)
320{
321 struct jump_entry *iter;
322
323 iter = iter_start;
324 while (iter < iter_stop) {
325 if (addr_conflict(iter, start, end))
326 return 1;
327 iter++;
328 }
329
330 return 0;
331}
332
333/*
334 * Update code which is definitely not currently executing.
335 * Architectures which need heavyweight synchronization to modify
336 * running code can override this to make the non-live update case
337 * cheaper.
338 */
339void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
340 enum jump_label_type type)
341{
342 arch_jump_label_transform(entry, type);
343}
344
345static inline struct jump_entry *static_key_entries(struct static_key *key)
346{
347 WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED);
348 return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);
349}
350
351static inline bool static_key_type(struct static_key *key)
352{
353 return key->type & JUMP_TYPE_TRUE;
354}
355
356static inline bool static_key_linked(struct static_key *key)
357{
358 return key->type & JUMP_TYPE_LINKED;
359}
360
361static inline void static_key_clear_linked(struct static_key *key)
362{
363 key->type &= ~JUMP_TYPE_LINKED;
364}
365
366static inline void static_key_set_linked(struct static_key *key)
367{
368 key->type |= JUMP_TYPE_LINKED;
369}
370
371/***
372 * A 'struct static_key' uses a union such that it either points directly
373 * to a table of 'struct jump_entry' or to a linked list of modules which in
374 * turn point to 'struct jump_entry' tables.
375 *
376 * The two lower bits of the pointer are used to keep track of which pointer
377 * type is in use and to store the initial branch direction, we use an access
378 * function which preserves these bits.
379 */
380static void static_key_set_entries(struct static_key *key,
381 struct jump_entry *entries)
382{
383 unsigned long type;
384
385 WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK);
386 type = key->type & JUMP_TYPE_MASK;
387 key->entries = entries;
388 key->type |= type;
389}
390
391static enum jump_label_type jump_label_type(struct jump_entry *entry)
392{
393 struct static_key *key = jump_entry_key(entry);
394 bool enabled = static_key_enabled(key);
395 bool branch = jump_entry_is_branch(entry);
396
397 /* See the comment in linux/jump_label.h */
398 return enabled ^ branch;
399}
400
401static bool jump_label_can_update(struct jump_entry *entry, bool init)
402{
403 /*
404 * Cannot update code that was in an init text area.
405 */
406 if (!init && jump_entry_is_init(entry))
407 return false;
408
409 if (!kernel_text_address(jump_entry_code(entry))) {
410 /*
411 * This skips patching built-in __exit, which
412 * is part of init_section_contains() but is
413 * not part of kernel_text_address().
414 *
415 * Skipping built-in __exit is fine since it
416 * will never be executed.
417 */
418 WARN_ONCE(!jump_entry_is_init(entry),
419 "can't patch jump_label at %pS",
420 (void *)jump_entry_code(entry));
421 return false;
422 }
423
424 return true;
425}
426
427#ifndef HAVE_JUMP_LABEL_BATCH
428static void __jump_label_update(struct static_key *key,
429 struct jump_entry *entry,
430 struct jump_entry *stop,
431 bool init)
432{
433 for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
434 if (jump_label_can_update(entry, init))
435 arch_jump_label_transform(entry, jump_label_type(entry));
436 }
437}
438#else
439static void __jump_label_update(struct static_key *key,
440 struct jump_entry *entry,
441 struct jump_entry *stop,
442 bool init)
443{
444 for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
445
446 if (!jump_label_can_update(entry, init))
447 continue;
448
449 if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) {
450 /*
451 * Queue is full: Apply the current queue and try again.
452 */
453 arch_jump_label_transform_apply();
454 BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry)));
455 }
456 }
457 arch_jump_label_transform_apply();
458}
459#endif
460
461void __init jump_label_init(void)
462{
463 struct jump_entry *iter_start = __start___jump_table;
464 struct jump_entry *iter_stop = __stop___jump_table;
465 struct static_key *key = NULL;
466 struct jump_entry *iter;
467
468 /*
469 * Since we are initializing the static_key.enabled field with
470 * with the 'raw' int values (to avoid pulling in atomic.h) in
471 * jump_label.h, let's make sure that is safe. There are only two
472 * cases to check since we initialize to 0 or 1.
473 */
474 BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0);
475 BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1);
476
477 if (static_key_initialized)
478 return;
479
480 cpus_read_lock();
481 jump_label_lock();
482 jump_label_sort_entries(iter_start, iter_stop);
483
484 for (iter = iter_start; iter < iter_stop; iter++) {
485 struct static_key *iterk;
486
487 /* rewrite NOPs */
488 if (jump_label_type(iter) == JUMP_LABEL_NOP)
489 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
490
491 if (init_section_contains((void *)jump_entry_code(iter), 1))
492 jump_entry_set_init(iter);
493
494 iterk = jump_entry_key(iter);
495 if (iterk == key)
496 continue;
497
498 key = iterk;
499 static_key_set_entries(key, iter);
500 }
501 static_key_initialized = true;
502 jump_label_unlock();
503 cpus_read_unlock();
504}
505
506#ifdef CONFIG_MODULES
507
508static enum jump_label_type jump_label_init_type(struct jump_entry *entry)
509{
510 struct static_key *key = jump_entry_key(entry);
511 bool type = static_key_type(key);
512 bool branch = jump_entry_is_branch(entry);
513
514 /* See the comment in linux/jump_label.h */
515 return type ^ branch;
516}
517
518struct static_key_mod {
519 struct static_key_mod *next;
520 struct jump_entry *entries;
521 struct module *mod;
522};
523
524static inline struct static_key_mod *static_key_mod(struct static_key *key)
525{
526 WARN_ON_ONCE(!static_key_linked(key));
527 return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK);
528}
529
530/***
531 * key->type and key->next are the same via union.
532 * This sets key->next and preserves the type bits.
533 *
534 * See additional comments above static_key_set_entries().
535 */
536static void static_key_set_mod(struct static_key *key,
537 struct static_key_mod *mod)
538{
539 unsigned long type;
540
541 WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK);
542 type = key->type & JUMP_TYPE_MASK;
543 key->next = mod;
544 key->type |= type;
545}
546
547static int __jump_label_mod_text_reserved(void *start, void *end)
548{
549 struct module *mod;
550 int ret;
551
552 preempt_disable();
553 mod = __module_text_address((unsigned long)start);
554 WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
555 if (!try_module_get(mod))
556 mod = NULL;
557 preempt_enable();
558
559 if (!mod)
560 return 0;
561
562 ret = __jump_label_text_reserved(mod->jump_entries,
563 mod->jump_entries + mod->num_jump_entries,
564 start, end);
565
566 module_put(mod);
567
568 return ret;
569}
570
571static void __jump_label_mod_update(struct static_key *key)
572{
573 struct static_key_mod *mod;
574
575 for (mod = static_key_mod(key); mod; mod = mod->next) {
576 struct jump_entry *stop;
577 struct module *m;
578
579 /*
580 * NULL if the static_key is defined in a module
581 * that does not use it
582 */
583 if (!mod->entries)
584 continue;
585
586 m = mod->mod;
587 if (!m)
588 stop = __stop___jump_table;
589 else
590 stop = m->jump_entries + m->num_jump_entries;
591 __jump_label_update(key, mod->entries, stop,
592 m && m->state == MODULE_STATE_COMING);
593 }
594}
595
596/***
597 * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
598 * @mod: module to patch
599 *
600 * Allow for run-time selection of the optimal nops. Before the module
601 * loads patch these with arch_get_jump_label_nop(), which is specified by
602 * the arch specific jump label code.
603 */
604void jump_label_apply_nops(struct module *mod)
605{
606 struct jump_entry *iter_start = mod->jump_entries;
607 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
608 struct jump_entry *iter;
609
610 /* if the module doesn't have jump label entries, just return */
611 if (iter_start == iter_stop)
612 return;
613
614 for (iter = iter_start; iter < iter_stop; iter++) {
615 /* Only write NOPs for arch_branch_static(). */
616 if (jump_label_init_type(iter) == JUMP_LABEL_NOP)
617 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
618 }
619}
620
621static int jump_label_add_module(struct module *mod)
622{
623 struct jump_entry *iter_start = mod->jump_entries;
624 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
625 struct jump_entry *iter;
626 struct static_key *key = NULL;
627 struct static_key_mod *jlm, *jlm2;
628
629 /* if the module doesn't have jump label entries, just return */
630 if (iter_start == iter_stop)
631 return 0;
632
633 jump_label_sort_entries(iter_start, iter_stop);
634
635 for (iter = iter_start; iter < iter_stop; iter++) {
636 struct static_key *iterk;
637
638 if (within_module_init(jump_entry_code(iter), mod))
639 jump_entry_set_init(iter);
640
641 iterk = jump_entry_key(iter);
642 if (iterk == key)
643 continue;
644
645 key = iterk;
646 if (within_module((unsigned long)key, mod)) {
647 static_key_set_entries(key, iter);
648 continue;
649 }
650 jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
651 if (!jlm)
652 return -ENOMEM;
653 if (!static_key_linked(key)) {
654 jlm2 = kzalloc(sizeof(struct static_key_mod),
655 GFP_KERNEL);
656 if (!jlm2) {
657 kfree(jlm);
658 return -ENOMEM;
659 }
660 preempt_disable();
661 jlm2->mod = __module_address((unsigned long)key);
662 preempt_enable();
663 jlm2->entries = static_key_entries(key);
664 jlm2->next = NULL;
665 static_key_set_mod(key, jlm2);
666 static_key_set_linked(key);
667 }
668 jlm->mod = mod;
669 jlm->entries = iter;
670 jlm->next = static_key_mod(key);
671 static_key_set_mod(key, jlm);
672 static_key_set_linked(key);
673
674 /* Only update if we've changed from our initial state */
675 if (jump_label_type(iter) != jump_label_init_type(iter))
676 __jump_label_update(key, iter, iter_stop, true);
677 }
678
679 return 0;
680}
681
682static void jump_label_del_module(struct module *mod)
683{
684 struct jump_entry *iter_start = mod->jump_entries;
685 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
686 struct jump_entry *iter;
687 struct static_key *key = NULL;
688 struct static_key_mod *jlm, **prev;
689
690 for (iter = iter_start; iter < iter_stop; iter++) {
691 if (jump_entry_key(iter) == key)
692 continue;
693
694 key = jump_entry_key(iter);
695
696 if (within_module((unsigned long)key, mod))
697 continue;
698
699 /* No memory during module load */
700 if (WARN_ON(!static_key_linked(key)))
701 continue;
702
703 prev = &key->next;
704 jlm = static_key_mod(key);
705
706 while (jlm && jlm->mod != mod) {
707 prev = &jlm->next;
708 jlm = jlm->next;
709 }
710
711 /* No memory during module load */
712 if (WARN_ON(!jlm))
713 continue;
714
715 if (prev == &key->next)
716 static_key_set_mod(key, jlm->next);
717 else
718 *prev = jlm->next;
719
720 kfree(jlm);
721
722 jlm = static_key_mod(key);
723 /* if only one etry is left, fold it back into the static_key */
724 if (jlm->next == NULL) {
725 static_key_set_entries(key, jlm->entries);
726 static_key_clear_linked(key);
727 kfree(jlm);
728 }
729 }
730}
731
732static int
733jump_label_module_notify(struct notifier_block *self, unsigned long val,
734 void *data)
735{
736 struct module *mod = data;
737 int ret = 0;
738
739 cpus_read_lock();
740 jump_label_lock();
741
742 switch (val) {
743 case MODULE_STATE_COMING:
744 ret = jump_label_add_module(mod);
745 if (ret) {
746 WARN(1, "Failed to allocate memory: jump_label may not work properly.\n");
747 jump_label_del_module(mod);
748 }
749 break;
750 case MODULE_STATE_GOING:
751 jump_label_del_module(mod);
752 break;
753 }
754
755 jump_label_unlock();
756 cpus_read_unlock();
757
758 return notifier_from_errno(ret);
759}
760
761static struct notifier_block jump_label_module_nb = {
762 .notifier_call = jump_label_module_notify,
763 .priority = 1, /* higher than tracepoints */
764};
765
766static __init int jump_label_init_module(void)
767{
768 return register_module_notifier(&jump_label_module_nb);
769}
770early_initcall(jump_label_init_module);
771
772#endif /* CONFIG_MODULES */
773
774/***
775 * jump_label_text_reserved - check if addr range is reserved
776 * @start: start text addr
777 * @end: end text addr
778 *
779 * checks if the text addr located between @start and @end
780 * overlaps with any of the jump label patch addresses. Code
781 * that wants to modify kernel text should first verify that
782 * it does not overlap with any of the jump label addresses.
783 * Caller must hold jump_label_mutex.
784 *
785 * returns 1 if there is an overlap, 0 otherwise
786 */
787int jump_label_text_reserved(void *start, void *end)
788{
789 int ret = __jump_label_text_reserved(__start___jump_table,
790 __stop___jump_table, start, end);
791
792 if (ret)
793 return ret;
794
795#ifdef CONFIG_MODULES
796 ret = __jump_label_mod_text_reserved(start, end);
797#endif
798 return ret;
799}
800
801static void jump_label_update(struct static_key *key)
802{
803 struct jump_entry *stop = __stop___jump_table;
804 bool init = system_state < SYSTEM_RUNNING;
805 struct jump_entry *entry;
806#ifdef CONFIG_MODULES
807 struct module *mod;
808
809 if (static_key_linked(key)) {
810 __jump_label_mod_update(key);
811 return;
812 }
813
814 preempt_disable();
815 mod = __module_address((unsigned long)key);
816 if (mod) {
817 stop = mod->jump_entries + mod->num_jump_entries;
818 init = mod->state == MODULE_STATE_COMING;
819 }
820 preempt_enable();
821#endif
822 entry = static_key_entries(key);
823 /* if there are no users, entry can be NULL */
824 if (entry)
825 __jump_label_update(key, entry, stop, init);
826}
827
828#ifdef CONFIG_STATIC_KEYS_SELFTEST
829static DEFINE_STATIC_KEY_TRUE(sk_true);
830static DEFINE_STATIC_KEY_FALSE(sk_false);
831
832static __init int jump_label_test(void)
833{
834 int i;
835
836 for (i = 0; i < 2; i++) {
837 WARN_ON(static_key_enabled(&sk_true.key) != true);
838 WARN_ON(static_key_enabled(&sk_false.key) != false);
839
840 WARN_ON(!static_branch_likely(&sk_true));
841 WARN_ON(!static_branch_unlikely(&sk_true));
842 WARN_ON(static_branch_likely(&sk_false));
843 WARN_ON(static_branch_unlikely(&sk_false));
844
845 static_branch_disable(&sk_true);
846 static_branch_enable(&sk_false);
847
848 WARN_ON(static_key_enabled(&sk_true.key) == true);
849 WARN_ON(static_key_enabled(&sk_false.key) == false);
850
851 WARN_ON(static_branch_likely(&sk_true));
852 WARN_ON(static_branch_unlikely(&sk_true));
853 WARN_ON(!static_branch_likely(&sk_false));
854 WARN_ON(!static_branch_unlikely(&sk_false));
855
856 static_branch_enable(&sk_true);
857 static_branch_disable(&sk_false);
858 }
859
860 return 0;
861}
862early_initcall(jump_label_test);
863#endif /* STATIC_KEYS_SELFTEST */