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Jason Baronbf5438fc2010-09-17 11:09:00 -04001/*
2 * jump label support
3 *
4 * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
Jason Barond430d3d2011-03-16 17:29:47 -04005 * Copyright (C) 2011 Peter Zijlstra <pzijlstr@redhat.com>
Jason Baronbf5438fc2010-09-17 11:09:00 -04006 *
7 */
Jason Baronbf5438fc2010-09-17 11:09:00 -04008#include <linux/memory.h>
9#include <linux/uaccess.h>
10#include <linux/module.h>
11#include <linux/list.h>
Jason Baronbf5438fc2010-09-17 11:09:00 -040012#include <linux/slab.h>
13#include <linux/sort.h>
14#include <linux/err.h>
Ingo Molnarc5905af2012-02-24 08:31:31 +010015#include <linux/static_key.h>
Andrew Jones851cf6e2013-08-09 19:51:57 +053016#include <linux/jump_label_ratelimit.h>
Jason Baronbf5438fc2010-09-17 11:09:00 -040017
18#ifdef HAVE_JUMP_LABEL
19
Jason Baronbf5438fc2010-09-17 11:09:00 -040020/* mutex to protect coming/going of the the jump_label table */
21static DEFINE_MUTEX(jump_label_mutex);
22
Jason Baron91bad2f2010-10-01 17:23:48 -040023void jump_label_lock(void)
24{
25 mutex_lock(&jump_label_mutex);
26}
27
28void jump_label_unlock(void)
29{
30 mutex_unlock(&jump_label_mutex);
31}
32
Jason Baronbf5438fc2010-09-17 11:09:00 -040033static int jump_label_cmp(const void *a, const void *b)
34{
35 const struct jump_entry *jea = a;
36 const struct jump_entry *jeb = b;
37
38 if (jea->key < jeb->key)
39 return -1;
40
41 if (jea->key > jeb->key)
42 return 1;
43
44 return 0;
45}
46
47static void
Jason Barond430d3d2011-03-16 17:29:47 -040048jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
Jason Baronbf5438fc2010-09-17 11:09:00 -040049{
50 unsigned long size;
51
52 size = (((unsigned long)stop - (unsigned long)start)
53 / sizeof(struct jump_entry));
54 sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
55}
56
Peter Zijlstra706249c2015-07-24 15:06:37 +020057static void jump_label_update(struct static_key *key);
Peter Zijlstraa1efb012015-07-24 14:55:40 +020058
Ingo Molnarc5905af2012-02-24 08:31:31 +010059void static_key_slow_inc(struct static_key *key)
Jason Baronbf5438fc2010-09-17 11:09:00 -040060{
Hannes Frederic Sowac4b2c0c2013-10-19 21:48:53 +020061 STATIC_KEY_CHECK_USE();
Jason Barond430d3d2011-03-16 17:29:47 -040062 if (atomic_inc_not_zero(&key->enabled))
63 return;
Jason Baronbf5438fc2010-09-17 11:09:00 -040064
Jason Baron91bad2f2010-10-01 17:23:48 -040065 jump_label_lock();
Peter Zijlstra706249c2015-07-24 15:06:37 +020066 if (atomic_inc_return(&key->enabled) == 1)
67 jump_label_update(key);
Jason Barond430d3d2011-03-16 17:29:47 -040068 jump_label_unlock();
69}
Ingo Molnarc5905af2012-02-24 08:31:31 +010070EXPORT_SYMBOL_GPL(static_key_slow_inc);
Jason Barond430d3d2011-03-16 17:29:47 -040071
Ingo Molnarc5905af2012-02-24 08:31:31 +010072static void __static_key_slow_dec(struct static_key *key,
Gleb Natapovb2029522011-11-27 17:59:09 +020073 unsigned long rate_limit, struct delayed_work *work)
Jason Barond430d3d2011-03-16 17:29:47 -040074{
Jason Baronfadf0462012-02-21 15:02:53 -050075 if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
76 WARN(atomic_read(&key->enabled) < 0,
77 "jump label: negative count!\n");
Jason Barond430d3d2011-03-16 17:29:47 -040078 return;
Jason Baronfadf0462012-02-21 15:02:53 -050079 }
Jason Barond430d3d2011-03-16 17:29:47 -040080
Gleb Natapovb2029522011-11-27 17:59:09 +020081 if (rate_limit) {
82 atomic_inc(&key->enabled);
83 schedule_delayed_work(work, rate_limit);
Ingo Molnarc5905af2012-02-24 08:31:31 +010084 } else {
Peter Zijlstra706249c2015-07-24 15:06:37 +020085 jump_label_update(key);
Ingo Molnarc5905af2012-02-24 08:31:31 +010086 }
Jason Baron91bad2f2010-10-01 17:23:48 -040087 jump_label_unlock();
Jason Baronbf5438fc2010-09-17 11:09:00 -040088}
89
Gleb Natapovb2029522011-11-27 17:59:09 +020090static void jump_label_update_timeout(struct work_struct *work)
91{
Ingo Molnarc5905af2012-02-24 08:31:31 +010092 struct static_key_deferred *key =
93 container_of(work, struct static_key_deferred, work.work);
94 __static_key_slow_dec(&key->key, 0, NULL);
Gleb Natapovb2029522011-11-27 17:59:09 +020095}
96
Ingo Molnarc5905af2012-02-24 08:31:31 +010097void static_key_slow_dec(struct static_key *key)
Gleb Natapovb2029522011-11-27 17:59:09 +020098{
Hannes Frederic Sowac4b2c0c2013-10-19 21:48:53 +020099 STATIC_KEY_CHECK_USE();
Ingo Molnarc5905af2012-02-24 08:31:31 +0100100 __static_key_slow_dec(key, 0, NULL);
Gleb Natapovb2029522011-11-27 17:59:09 +0200101}
Ingo Molnarc5905af2012-02-24 08:31:31 +0100102EXPORT_SYMBOL_GPL(static_key_slow_dec);
Gleb Natapovb2029522011-11-27 17:59:09 +0200103
Ingo Molnarc5905af2012-02-24 08:31:31 +0100104void static_key_slow_dec_deferred(struct static_key_deferred *key)
Gleb Natapovb2029522011-11-27 17:59:09 +0200105{
Hannes Frederic Sowac4b2c0c2013-10-19 21:48:53 +0200106 STATIC_KEY_CHECK_USE();
Ingo Molnarc5905af2012-02-24 08:31:31 +0100107 __static_key_slow_dec(&key->key, key->timeout, &key->work);
Gleb Natapovb2029522011-11-27 17:59:09 +0200108}
Ingo Molnarc5905af2012-02-24 08:31:31 +0100109EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
Gleb Natapovb2029522011-11-27 17:59:09 +0200110
Ingo Molnarc5905af2012-02-24 08:31:31 +0100111void jump_label_rate_limit(struct static_key_deferred *key,
Gleb Natapovb2029522011-11-27 17:59:09 +0200112 unsigned long rl)
113{
Hannes Frederic Sowac4b2c0c2013-10-19 21:48:53 +0200114 STATIC_KEY_CHECK_USE();
Gleb Natapovb2029522011-11-27 17:59:09 +0200115 key->timeout = rl;
116 INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
117}
Gleb Natapova181dc12012-08-05 15:58:29 +0300118EXPORT_SYMBOL_GPL(jump_label_rate_limit);
Gleb Natapovb2029522011-11-27 17:59:09 +0200119
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400120static int addr_conflict(struct jump_entry *entry, void *start, void *end)
121{
122 if (entry->code <= (unsigned long)end &&
123 entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
124 return 1;
125
126 return 0;
127}
128
Jason Barond430d3d2011-03-16 17:29:47 -0400129static int __jump_label_text_reserved(struct jump_entry *iter_start,
130 struct jump_entry *iter_stop, void *start, void *end)
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400131{
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400132 struct jump_entry *iter;
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400133
Jason Barond430d3d2011-03-16 17:29:47 -0400134 iter = iter_start;
135 while (iter < iter_stop) {
136 if (addr_conflict(iter, start, end))
137 return 1;
138 iter++;
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400139 }
Jason Barond430d3d2011-03-16 17:29:47 -0400140
141 return 0;
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400142}
143
Peter Zijlstra706249c2015-07-24 15:06:37 +0200144/*
Jeremy Fitzhardinge20284aa2011-10-03 11:01:46 -0700145 * Update code which is definitely not currently executing.
146 * Architectures which need heavyweight synchronization to modify
147 * running code can override this to make the non-live update case
148 * cheaper.
149 */
Peter Zijlstra9cdbe1c2011-12-06 17:27:29 +0100150void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
Jeremy Fitzhardinge20284aa2011-10-03 11:01:46 -0700151 enum jump_label_type type)
152{
Peter Zijlstra706249c2015-07-24 15:06:37 +0200153 arch_jump_label_transform(entry, type);
Jason Barond430d3d2011-03-16 17:29:47 -0400154}
155
Peter Zijlstraa1efb012015-07-24 14:55:40 +0200156static inline struct jump_entry *static_key_entries(struct static_key *key)
157{
158 return (struct jump_entry *)((unsigned long)key->entries & ~JUMP_TYPE_MASK);
159}
160
Peter Zijlstra706249c2015-07-24 15:06:37 +0200161static inline bool static_key_type(struct static_key *key)
162{
163 return (unsigned long)key->entries & JUMP_TYPE_MASK;
164}
165
Peter Zijlstra7dcfd912015-07-24 15:02:27 +0200166static inline struct static_key *jump_entry_key(struct jump_entry *entry)
167{
Peter Zijlstra11276d52015-07-24 15:09:55 +0200168 return (struct static_key *)((unsigned long)entry->key & ~1UL);
169}
170
171static bool jump_entry_branch(struct jump_entry *entry)
172{
173 return (unsigned long)entry->key & 1UL;
Peter Zijlstra7dcfd912015-07-24 15:02:27 +0200174}
175
Peter Zijlstra706249c2015-07-24 15:06:37 +0200176static enum jump_label_type jump_label_type(struct jump_entry *entry)
Ingo Molnarc5905af2012-02-24 08:31:31 +0100177{
Peter Zijlstra706249c2015-07-24 15:06:37 +0200178 struct static_key *key = jump_entry_key(entry);
Peter Zijlstraa1efb012015-07-24 14:55:40 +0200179 bool enabled = static_key_enabled(key);
Peter Zijlstra11276d52015-07-24 15:09:55 +0200180 bool branch = jump_entry_branch(entry);
Ingo Molnarc5905af2012-02-24 08:31:31 +0100181
Peter Zijlstra11276d52015-07-24 15:09:55 +0200182 /* See the comment in linux/jump_label.h */
183 return enabled ^ branch;
Ingo Molnarc5905af2012-02-24 08:31:31 +0100184}
185
Peter Zijlstra706249c2015-07-24 15:06:37 +0200186static void __jump_label_update(struct static_key *key,
187 struct jump_entry *entry,
188 struct jump_entry *stop)
189{
190 for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
191 /*
192 * entry->code set to 0 invalidates module init text sections
193 * kernel_text_address() verifies we are not in core kernel
194 * init code, see jump_label_invalidate_module_init().
195 */
196 if (entry->code && kernel_text_address(entry->code))
197 arch_jump_label_transform(entry, jump_label_type(entry));
198 }
199}
200
Jeremy Fitzhardinge97ce2c82011-10-12 16:17:54 -0700201void __init jump_label_init(void)
Jason Barond430d3d2011-03-16 17:29:47 -0400202{
203 struct jump_entry *iter_start = __start___jump_table;
204 struct jump_entry *iter_stop = __stop___jump_table;
Ingo Molnarc5905af2012-02-24 08:31:31 +0100205 struct static_key *key = NULL;
Jason Barond430d3d2011-03-16 17:29:47 -0400206 struct jump_entry *iter;
207
208 jump_label_lock();
209 jump_label_sort_entries(iter_start, iter_stop);
210
211 for (iter = iter_start; iter < iter_stop; iter++) {
Ingo Molnarc5905af2012-02-24 08:31:31 +0100212 struct static_key *iterk;
Jeremy Fitzhardinge37348802011-09-29 11:10:05 -0700213
Peter Zijlstra11276d52015-07-24 15:09:55 +0200214 /* rewrite NOPs */
215 if (jump_label_type(iter) == JUMP_LABEL_NOP)
216 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
217
Peter Zijlstra7dcfd912015-07-24 15:02:27 +0200218 iterk = jump_entry_key(iter);
Jeremy Fitzhardinge37348802011-09-29 11:10:05 -0700219 if (iterk == key)
Jason Barond430d3d2011-03-16 17:29:47 -0400220 continue;
221
Jeremy Fitzhardinge37348802011-09-29 11:10:05 -0700222 key = iterk;
Ingo Molnarc5905af2012-02-24 08:31:31 +0100223 /*
224 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
225 */
226 *((unsigned long *)&key->entries) += (unsigned long)iter;
Jason Barond430d3d2011-03-16 17:29:47 -0400227#ifdef CONFIG_MODULES
228 key->next = NULL;
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400229#endif
Jason Barond430d3d2011-03-16 17:29:47 -0400230 }
Hannes Frederic Sowac4b2c0c2013-10-19 21:48:53 +0200231 static_key_initialized = true;
Jason Barond430d3d2011-03-16 17:29:47 -0400232 jump_label_unlock();
Jason Barond430d3d2011-03-16 17:29:47 -0400233}
Jason Barond430d3d2011-03-16 17:29:47 -0400234
235#ifdef CONFIG_MODULES
236
Peter Zijlstra11276d52015-07-24 15:09:55 +0200237static enum jump_label_type jump_label_init_type(struct jump_entry *entry)
238{
239 struct static_key *key = jump_entry_key(entry);
240 bool type = static_key_type(key);
241 bool branch = jump_entry_branch(entry);
242
243 /* See the comment in linux/jump_label.h */
244 return type ^ branch;
245}
246
Ingo Molnarc5905af2012-02-24 08:31:31 +0100247struct static_key_mod {
248 struct static_key_mod *next;
Jason Barond430d3d2011-03-16 17:29:47 -0400249 struct jump_entry *entries;
250 struct module *mod;
251};
252
253static int __jump_label_mod_text_reserved(void *start, void *end)
254{
255 struct module *mod;
256
257 mod = __module_text_address((unsigned long)start);
258 if (!mod)
259 return 0;
260
261 WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
262
263 return __jump_label_text_reserved(mod->jump_entries,
264 mod->jump_entries + mod->num_jump_entries,
265 start, end);
266}
267
Peter Zijlstra706249c2015-07-24 15:06:37 +0200268static void __jump_label_mod_update(struct static_key *key)
Jason Barond430d3d2011-03-16 17:29:47 -0400269{
Peter Zijlstra706249c2015-07-24 15:06:37 +0200270 struct static_key_mod *mod;
Jason Barond430d3d2011-03-16 17:29:47 -0400271
Peter Zijlstra706249c2015-07-24 15:06:37 +0200272 for (mod = key->next; mod; mod = mod->next) {
Jiri Olsa7cbc5b82011-05-10 12:43:46 +0200273 struct module *m = mod->mod;
274
275 __jump_label_update(key, mod->entries,
Peter Zijlstra706249c2015-07-24 15:06:37 +0200276 m->jump_entries + m->num_jump_entries);
Jason Barond430d3d2011-03-16 17:29:47 -0400277 }
278}
279
280/***
281 * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
282 * @mod: module to patch
283 *
284 * Allow for run-time selection of the optimal nops. Before the module
285 * loads patch these with arch_get_jump_label_nop(), which is specified by
286 * the arch specific jump label code.
287 */
288void jump_label_apply_nops(struct module *mod)
289{
290 struct jump_entry *iter_start = mod->jump_entries;
291 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
292 struct jump_entry *iter;
293
294 /* if the module doesn't have jump label entries, just return */
295 if (iter_start == iter_stop)
296 return;
297
Peter Zijlstra11276d52015-07-24 15:09:55 +0200298 for (iter = iter_start; iter < iter_stop; iter++) {
299 /* Only write NOPs for arch_branch_static(). */
300 if (jump_label_init_type(iter) == JUMP_LABEL_NOP)
301 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
302 }
Jason Barond430d3d2011-03-16 17:29:47 -0400303}
304
305static int jump_label_add_module(struct module *mod)
306{
307 struct jump_entry *iter_start = mod->jump_entries;
308 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
309 struct jump_entry *iter;
Ingo Molnarc5905af2012-02-24 08:31:31 +0100310 struct static_key *key = NULL;
311 struct static_key_mod *jlm;
Jason Barond430d3d2011-03-16 17:29:47 -0400312
313 /* if the module doesn't have jump label entries, just return */
314 if (iter_start == iter_stop)
315 return 0;
316
317 jump_label_sort_entries(iter_start, iter_stop);
318
319 for (iter = iter_start; iter < iter_stop; iter++) {
Ingo Molnarc5905af2012-02-24 08:31:31 +0100320 struct static_key *iterk;
321
Peter Zijlstra7dcfd912015-07-24 15:02:27 +0200322 iterk = jump_entry_key(iter);
Ingo Molnarc5905af2012-02-24 08:31:31 +0100323 if (iterk == key)
Jason Barond430d3d2011-03-16 17:29:47 -0400324 continue;
325
Ingo Molnarc5905af2012-02-24 08:31:31 +0100326 key = iterk;
Peter Zijlstrabed831f2015-05-27 11:09:35 +0930327 if (within_module(iter->key, mod)) {
Ingo Molnarc5905af2012-02-24 08:31:31 +0100328 /*
329 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
330 */
331 *((unsigned long *)&key->entries) += (unsigned long)iter;
Jason Barond430d3d2011-03-16 17:29:47 -0400332 key->next = NULL;
333 continue;
334 }
Ingo Molnarc5905af2012-02-24 08:31:31 +0100335 jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
Jason Barond430d3d2011-03-16 17:29:47 -0400336 if (!jlm)
337 return -ENOMEM;
Jason Barond430d3d2011-03-16 17:29:47 -0400338 jlm->mod = mod;
339 jlm->entries = iter;
340 jlm->next = key->next;
341 key->next = jlm;
342
Peter Zijlstra11276d52015-07-24 15:09:55 +0200343 /* Only update if we've changed from our initial state */
344 if (jump_label_type(iter) != jump_label_init_type(iter))
Peter Zijlstra706249c2015-07-24 15:06:37 +0200345 __jump_label_update(key, iter, iter_stop);
Jason Barond430d3d2011-03-16 17:29:47 -0400346 }
347
348 return 0;
349}
350
351static void jump_label_del_module(struct module *mod)
352{
353 struct jump_entry *iter_start = mod->jump_entries;
354 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
355 struct jump_entry *iter;
Ingo Molnarc5905af2012-02-24 08:31:31 +0100356 struct static_key *key = NULL;
357 struct static_key_mod *jlm, **prev;
Jason Barond430d3d2011-03-16 17:29:47 -0400358
359 for (iter = iter_start; iter < iter_stop; iter++) {
Peter Zijlstra7dcfd912015-07-24 15:02:27 +0200360 if (jump_entry_key(iter) == key)
Jason Barond430d3d2011-03-16 17:29:47 -0400361 continue;
362
Peter Zijlstra7dcfd912015-07-24 15:02:27 +0200363 key = jump_entry_key(iter);
Jason Barond430d3d2011-03-16 17:29:47 -0400364
Peter Zijlstrabed831f2015-05-27 11:09:35 +0930365 if (within_module(iter->key, mod))
Jason Barond430d3d2011-03-16 17:29:47 -0400366 continue;
367
368 prev = &key->next;
369 jlm = key->next;
370
371 while (jlm && jlm->mod != mod) {
372 prev = &jlm->next;
373 jlm = jlm->next;
374 }
375
376 if (jlm) {
377 *prev = jlm->next;
378 kfree(jlm);
379 }
380 }
381}
382
383static void jump_label_invalidate_module_init(struct module *mod)
384{
385 struct jump_entry *iter_start = mod->jump_entries;
386 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
387 struct jump_entry *iter;
388
389 for (iter = iter_start; iter < iter_stop; iter++) {
390 if (within_module_init(iter->code, mod))
391 iter->code = 0;
392 }
393}
394
395static int
396jump_label_module_notify(struct notifier_block *self, unsigned long val,
397 void *data)
398{
399 struct module *mod = data;
400 int ret = 0;
401
402 switch (val) {
403 case MODULE_STATE_COMING:
404 jump_label_lock();
405 ret = jump_label_add_module(mod);
406 if (ret)
407 jump_label_del_module(mod);
408 jump_label_unlock();
409 break;
410 case MODULE_STATE_GOING:
411 jump_label_lock();
412 jump_label_del_module(mod);
413 jump_label_unlock();
414 break;
415 case MODULE_STATE_LIVE:
416 jump_label_lock();
417 jump_label_invalidate_module_init(mod);
418 jump_label_unlock();
419 break;
420 }
421
422 return notifier_from_errno(ret);
423}
424
425struct notifier_block jump_label_module_nb = {
426 .notifier_call = jump_label_module_notify,
427 .priority = 1, /* higher than tracepoints */
428};
429
430static __init int jump_label_init_module(void)
431{
432 return register_module_notifier(&jump_label_module_nb);
433}
434early_initcall(jump_label_init_module);
435
436#endif /* CONFIG_MODULES */
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400437
438/***
439 * jump_label_text_reserved - check if addr range is reserved
440 * @start: start text addr
441 * @end: end text addr
442 *
443 * checks if the text addr located between @start and @end
444 * overlaps with any of the jump label patch addresses. Code
445 * that wants to modify kernel text should first verify that
446 * it does not overlap with any of the jump label addresses.
Jason Baron91bad2f2010-10-01 17:23:48 -0400447 * Caller must hold jump_label_mutex.
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400448 *
449 * returns 1 if there is an overlap, 0 otherwise
450 */
451int jump_label_text_reserved(void *start, void *end)
452{
Jason Barond430d3d2011-03-16 17:29:47 -0400453 int ret = __jump_label_text_reserved(__start___jump_table,
454 __stop___jump_table, start, end);
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400455
Jason Barond430d3d2011-03-16 17:29:47 -0400456 if (ret)
457 return ret;
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400458
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400459#ifdef CONFIG_MODULES
Jason Barond430d3d2011-03-16 17:29:47 -0400460 ret = __jump_label_mod_text_reserved(start, end);
Jason Baron4c3ef6d2010-09-17 11:09:08 -0400461#endif
Jason Baronbf5438fc2010-09-17 11:09:00 -0400462 return ret;
463}
Jason Barond430d3d2011-03-16 17:29:47 -0400464
Peter Zijlstra706249c2015-07-24 15:06:37 +0200465static void jump_label_update(struct static_key *key)
Jason Barond430d3d2011-03-16 17:29:47 -0400466{
Ingo Molnarc5905af2012-02-24 08:31:31 +0100467 struct jump_entry *stop = __stop___jump_table;
Peter Zijlstraa1efb012015-07-24 14:55:40 +0200468 struct jump_entry *entry = static_key_entries(key);
Jason Baronbf5438fc2010-09-17 11:09:00 -0400469#ifdef CONFIG_MODULES
Peter Zijlstrabed831f2015-05-27 11:09:35 +0930470 struct module *mod;
Xiao Guangrong140fe3b2011-06-21 10:35:55 +0800471
Peter Zijlstra706249c2015-07-24 15:06:37 +0200472 __jump_label_mod_update(key);
Xiao Guangrong140fe3b2011-06-21 10:35:55 +0800473
Peter Zijlstrabed831f2015-05-27 11:09:35 +0930474 preempt_disable();
475 mod = __module_address((unsigned long)key);
Xiao Guangrong140fe3b2011-06-21 10:35:55 +0800476 if (mod)
477 stop = mod->jump_entries + mod->num_jump_entries;
Peter Zijlstrabed831f2015-05-27 11:09:35 +0930478 preempt_enable();
Jason Barond430d3d2011-03-16 17:29:47 -0400479#endif
Xiao Guangrong140fe3b2011-06-21 10:35:55 +0800480 /* if there are no users, entry can be NULL */
481 if (entry)
Peter Zijlstra706249c2015-07-24 15:06:37 +0200482 __jump_label_update(key, entry, stop);
Jason Baronbf5438fc2010-09-17 11:09:00 -0400483}
484
Peter Zijlstra1987c942015-07-27 18:32:09 +0200485#ifdef CONFIG_STATIC_KEYS_SELFTEST
486static DEFINE_STATIC_KEY_TRUE(sk_true);
487static DEFINE_STATIC_KEY_FALSE(sk_false);
488
489static __init int jump_label_test(void)
490{
491 int i;
492
493 for (i = 0; i < 2; i++) {
494 WARN_ON(static_key_enabled(&sk_true.key) != true);
495 WARN_ON(static_key_enabled(&sk_false.key) != false);
496
497 WARN_ON(!static_branch_likely(&sk_true));
498 WARN_ON(!static_branch_unlikely(&sk_true));
499 WARN_ON(static_branch_likely(&sk_false));
500 WARN_ON(static_branch_unlikely(&sk_false));
501
502 static_branch_disable(&sk_true);
503 static_branch_enable(&sk_false);
504
505 WARN_ON(static_key_enabled(&sk_true.key) == true);
506 WARN_ON(static_key_enabled(&sk_false.key) == false);
507
508 WARN_ON(static_branch_likely(&sk_true));
509 WARN_ON(static_branch_unlikely(&sk_true));
510 WARN_ON(!static_branch_likely(&sk_false));
511 WARN_ON(!static_branch_unlikely(&sk_false));
512
513 static_branch_enable(&sk_true);
514 static_branch_disable(&sk_false);
515 }
516
517 return 0;
518}
519late_initcall(jump_label_test);
520#endif /* STATIC_KEYS_SELFTEST */
521
522#endif /* HAVE_JUMP_LABEL */