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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
18#ifdef HAVE_JUMP_LABEL
19
20/* mutex to protect coming/going of the the jump_label table */
21static DEFINE_MUTEX(jump_label_mutex);
22
23void 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
33static 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
48jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
49{
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
57static void jump_label_update(struct static_key *key);
58
59void static_key_slow_inc(struct static_key *key)
60{
61 STATIC_KEY_CHECK_USE();
62 if (atomic_inc_not_zero(&key->enabled))
63 return;
64
65 jump_label_lock();
66 if (atomic_inc_return(&key->enabled) == 1)
67 jump_label_update(key);
68 jump_label_unlock();
69}
70EXPORT_SYMBOL_GPL(static_key_slow_inc);
71
72static void __static_key_slow_dec(struct static_key *key,
73 unsigned long rate_limit, struct delayed_work *work)
74{
75 if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
76 WARN(atomic_read(&key->enabled) < 0,
77 "jump label: negative count!\n");
78 return;
79 }
80
81 if (rate_limit) {
82 atomic_inc(&key->enabled);
83 schedule_delayed_work(work, rate_limit);
84 } else {
85 jump_label_update(key);
86 }
87 jump_label_unlock();
88}
89
90static void jump_label_update_timeout(struct work_struct *work)
91{
92 struct static_key_deferred *key =
93 container_of(work, struct static_key_deferred, work.work);
94 __static_key_slow_dec(&key->key, 0, NULL);
95}
96
97void static_key_slow_dec(struct static_key *key)
98{
99 STATIC_KEY_CHECK_USE();
100 __static_key_slow_dec(key, 0, NULL);
101}
102EXPORT_SYMBOL_GPL(static_key_slow_dec);
103
104void static_key_slow_dec_deferred(struct static_key_deferred *key)
105{
106 STATIC_KEY_CHECK_USE();
107 __static_key_slow_dec(&key->key, key->timeout, &key->work);
108}
109EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
110
111void jump_label_rate_limit(struct static_key_deferred *key,
112 unsigned long rl)
113{
114 STATIC_KEY_CHECK_USE();
115 key->timeout = rl;
116 INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
117}
118EXPORT_SYMBOL_GPL(jump_label_rate_limit);
119
120static 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
129static int __jump_label_text_reserved(struct jump_entry *iter_start,
130 struct jump_entry *iter_stop, void *start, void *end)
131{
132 struct jump_entry *iter;
133
134 iter = iter_start;
135 while (iter < iter_stop) {
136 if (addr_conflict(iter, start, end))
137 return 1;
138 iter++;
139 }
140
141 return 0;
142}
143
144/*
145 * 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 */
150void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
151 enum jump_label_type type)
152{
153 arch_jump_label_transform(entry, type);
154}
155
156static 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
161static inline bool static_key_type(struct static_key *key)
162{
163 return (unsigned long)key->entries & JUMP_TYPE_MASK;
164}
165
166static inline struct static_key *jump_entry_key(struct jump_entry *entry)
167{
168 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;
174}
175
176static enum jump_label_type jump_label_type(struct jump_entry *entry)
177{
178 struct static_key *key = jump_entry_key(entry);
179 bool enabled = static_key_enabled(key);
180 bool branch = jump_entry_branch(entry);
181
182 /* See the comment in linux/jump_label.h */
183 return enabled ^ branch;
184}
185
186static 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
201void __init jump_label_init(void)
202{
203 struct jump_entry *iter_start = __start___jump_table;
204 struct jump_entry *iter_stop = __stop___jump_table;
205 struct static_key *key = NULL;
206 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++) {
212 struct static_key *iterk;
213
214 /* rewrite NOPs */
215 if (jump_label_type(iter) == JUMP_LABEL_NOP)
216 arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
217
218 iterk = jump_entry_key(iter);
219 if (iterk == key)
220 continue;
221
222 key = iterk;
223 /*
224 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
225 */
226 *((unsigned long *)&key->entries) += (unsigned long)iter;
227#ifdef CONFIG_MODULES
228 key->next = NULL;
229#endif
230 }
231 static_key_initialized = true;
232 jump_label_unlock();
233}
234
235#ifdef CONFIG_MODULES
236
237static 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
247struct static_key_mod {
248 struct static_key_mod *next;
249 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
268static void __jump_label_mod_update(struct static_key *key)
269{
270 struct static_key_mod *mod;
271
272 for (mod = key->next; mod; mod = mod->next) {
273 struct module *m = mod->mod;
274
275 __jump_label_update(key, mod->entries,
276 m->jump_entries + m->num_jump_entries);
277 }
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
298 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 }
303}
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;
310 struct static_key *key = NULL;
311 struct static_key_mod *jlm;
312
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++) {
320 struct static_key *iterk;
321
322 iterk = jump_entry_key(iter);
323 if (iterk == key)
324 continue;
325
326 key = iterk;
327 if (within_module(iter->key, mod)) {
328 /*
329 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
330 */
331 *((unsigned long *)&key->entries) += (unsigned long)iter;
332 key->next = NULL;
333 continue;
334 }
335 jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
336 if (!jlm)
337 return -ENOMEM;
338 jlm->mod = mod;
339 jlm->entries = iter;
340 jlm->next = key->next;
341 key->next = jlm;
342
343 /* Only update if we've changed from our initial state */
344 if (jump_label_type(iter) != jump_label_init_type(iter))
345 __jump_label_update(key, iter, iter_stop);
346 }
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;
356 struct static_key *key = NULL;
357 struct static_key_mod *jlm, **prev;
358
359 for (iter = iter_start; iter < iter_stop; iter++) {
360 if (jump_entry_key(iter) == key)
361 continue;
362
363 key = jump_entry_key(iter);
364
365 if (within_module(iter->key, mod))
366 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 */
437
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.
447 * Caller must hold jump_label_mutex.
448 *
449 * returns 1 if there is an overlap, 0 otherwise
450 */
451int jump_label_text_reserved(void *start, void *end)
452{
453 int ret = __jump_label_text_reserved(__start___jump_table,
454 __stop___jump_table, start, end);
455
456 if (ret)
457 return ret;
458
459#ifdef CONFIG_MODULES
460 ret = __jump_label_mod_text_reserved(start, end);
461#endif
462 return ret;
463}
464
465static void jump_label_update(struct static_key *key)
466{
467 struct jump_entry *stop = __stop___jump_table;
468 struct jump_entry *entry = static_key_entries(key);
469#ifdef CONFIG_MODULES
470 struct module *mod;
471
472 __jump_label_mod_update(key);
473
474 preempt_disable();
475 mod = __module_address((unsigned long)key);
476 if (mod)
477 stop = mod->jump_entries + mod->num_jump_entries;
478 preempt_enable();
479#endif
480 /* if there are no users, entry can be NULL */
481 if (entry)
482 __jump_label_update(key, entry, stop);
483}
484
485#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 */
1/*
2 * jump label support
3 *
4 * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
5 * Copyright (C) 2011 Peter Zijlstra <pzijlstr@redhat.com>
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/jump_label.h>
16
17#ifdef HAVE_JUMP_LABEL
18
19/* mutex to protect coming/going of the the jump_label table */
20static DEFINE_MUTEX(jump_label_mutex);
21
22void jump_label_lock(void)
23{
24 mutex_lock(&jump_label_mutex);
25}
26
27void jump_label_unlock(void)
28{
29 mutex_unlock(&jump_label_mutex);
30}
31
32bool jump_label_enabled(struct jump_label_key *key)
33{
34 return !!atomic_read(&key->enabled);
35}
36
37static int jump_label_cmp(const void *a, const void *b)
38{
39 const struct jump_entry *jea = a;
40 const struct jump_entry *jeb = b;
41
42 if (jea->key < jeb->key)
43 return -1;
44
45 if (jea->key > jeb->key)
46 return 1;
47
48 return 0;
49}
50
51static void
52jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
53{
54 unsigned long size;
55
56 size = (((unsigned long)stop - (unsigned long)start)
57 / sizeof(struct jump_entry));
58 sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
59}
60
61static void jump_label_update(struct jump_label_key *key, int enable);
62
63void jump_label_inc(struct jump_label_key *key)
64{
65 if (atomic_inc_not_zero(&key->enabled))
66 return;
67
68 jump_label_lock();
69 if (atomic_add_return(1, &key->enabled) == 1)
70 jump_label_update(key, JUMP_LABEL_ENABLE);
71 jump_label_unlock();
72}
73
74void jump_label_dec(struct jump_label_key *key)
75{
76 if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex))
77 return;
78
79 jump_label_update(key, JUMP_LABEL_DISABLE);
80 jump_label_unlock();
81}
82
83static int addr_conflict(struct jump_entry *entry, void *start, void *end)
84{
85 if (entry->code <= (unsigned long)end &&
86 entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
87 return 1;
88
89 return 0;
90}
91
92static int __jump_label_text_reserved(struct jump_entry *iter_start,
93 struct jump_entry *iter_stop, void *start, void *end)
94{
95 struct jump_entry *iter;
96
97 iter = iter_start;
98 while (iter < iter_stop) {
99 if (addr_conflict(iter, start, end))
100 return 1;
101 iter++;
102 }
103
104 return 0;
105}
106
107static void __jump_label_update(struct jump_label_key *key,
108 struct jump_entry *entry,
109 struct jump_entry *stop, int enable)
110{
111 for (; (entry < stop) &&
112 (entry->key == (jump_label_t)(unsigned long)key);
113 entry++) {
114 /*
115 * entry->code set to 0 invalidates module init text sections
116 * kernel_text_address() verifies we are not in core kernel
117 * init code, see jump_label_invalidate_module_init().
118 */
119 if (entry->code && kernel_text_address(entry->code))
120 arch_jump_label_transform(entry, enable);
121 }
122}
123
124/*
125 * Not all archs need this.
126 */
127void __weak arch_jump_label_text_poke_early(jump_label_t addr)
128{
129}
130
131static __init int jump_label_init(void)
132{
133 struct jump_entry *iter_start = __start___jump_table;
134 struct jump_entry *iter_stop = __stop___jump_table;
135 struct jump_label_key *key = NULL;
136 struct jump_entry *iter;
137
138 jump_label_lock();
139 jump_label_sort_entries(iter_start, iter_stop);
140
141 for (iter = iter_start; iter < iter_stop; iter++) {
142 arch_jump_label_text_poke_early(iter->code);
143 if (iter->key == (jump_label_t)(unsigned long)key)
144 continue;
145
146 key = (struct jump_label_key *)(unsigned long)iter->key;
147 atomic_set(&key->enabled, 0);
148 key->entries = iter;
149#ifdef CONFIG_MODULES
150 key->next = NULL;
151#endif
152 }
153 jump_label_unlock();
154
155 return 0;
156}
157early_initcall(jump_label_init);
158
159#ifdef CONFIG_MODULES
160
161struct jump_label_mod {
162 struct jump_label_mod *next;
163 struct jump_entry *entries;
164 struct module *mod;
165};
166
167static int __jump_label_mod_text_reserved(void *start, void *end)
168{
169 struct module *mod;
170
171 mod = __module_text_address((unsigned long)start);
172 if (!mod)
173 return 0;
174
175 WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
176
177 return __jump_label_text_reserved(mod->jump_entries,
178 mod->jump_entries + mod->num_jump_entries,
179 start, end);
180}
181
182static void __jump_label_mod_update(struct jump_label_key *key, int enable)
183{
184 struct jump_label_mod *mod = key->next;
185
186 while (mod) {
187 struct module *m = mod->mod;
188
189 __jump_label_update(key, mod->entries,
190 m->jump_entries + m->num_jump_entries,
191 enable);
192 mod = mod->next;
193 }
194}
195
196/***
197 * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
198 * @mod: module to patch
199 *
200 * Allow for run-time selection of the optimal nops. Before the module
201 * loads patch these with arch_get_jump_label_nop(), which is specified by
202 * the arch specific jump label code.
203 */
204void jump_label_apply_nops(struct module *mod)
205{
206 struct jump_entry *iter_start = mod->jump_entries;
207 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
208 struct jump_entry *iter;
209
210 /* if the module doesn't have jump label entries, just return */
211 if (iter_start == iter_stop)
212 return;
213
214 for (iter = iter_start; iter < iter_stop; iter++)
215 arch_jump_label_text_poke_early(iter->code);
216}
217
218static int jump_label_add_module(struct module *mod)
219{
220 struct jump_entry *iter_start = mod->jump_entries;
221 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
222 struct jump_entry *iter;
223 struct jump_label_key *key = NULL;
224 struct jump_label_mod *jlm;
225
226 /* if the module doesn't have jump label entries, just return */
227 if (iter_start == iter_stop)
228 return 0;
229
230 jump_label_sort_entries(iter_start, iter_stop);
231
232 for (iter = iter_start; iter < iter_stop; iter++) {
233 if (iter->key == (jump_label_t)(unsigned long)key)
234 continue;
235
236 key = (struct jump_label_key *)(unsigned long)iter->key;
237
238 if (__module_address(iter->key) == mod) {
239 atomic_set(&key->enabled, 0);
240 key->entries = iter;
241 key->next = NULL;
242 continue;
243 }
244
245 jlm = kzalloc(sizeof(struct jump_label_mod), GFP_KERNEL);
246 if (!jlm)
247 return -ENOMEM;
248
249 jlm->mod = mod;
250 jlm->entries = iter;
251 jlm->next = key->next;
252 key->next = jlm;
253
254 if (jump_label_enabled(key))
255 __jump_label_update(key, iter, iter_stop,
256 JUMP_LABEL_ENABLE);
257 }
258
259 return 0;
260}
261
262static void jump_label_del_module(struct module *mod)
263{
264 struct jump_entry *iter_start = mod->jump_entries;
265 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
266 struct jump_entry *iter;
267 struct jump_label_key *key = NULL;
268 struct jump_label_mod *jlm, **prev;
269
270 for (iter = iter_start; iter < iter_stop; iter++) {
271 if (iter->key == (jump_label_t)(unsigned long)key)
272 continue;
273
274 key = (struct jump_label_key *)(unsigned long)iter->key;
275
276 if (__module_address(iter->key) == mod)
277 continue;
278
279 prev = &key->next;
280 jlm = key->next;
281
282 while (jlm && jlm->mod != mod) {
283 prev = &jlm->next;
284 jlm = jlm->next;
285 }
286
287 if (jlm) {
288 *prev = jlm->next;
289 kfree(jlm);
290 }
291 }
292}
293
294static void jump_label_invalidate_module_init(struct module *mod)
295{
296 struct jump_entry *iter_start = mod->jump_entries;
297 struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
298 struct jump_entry *iter;
299
300 for (iter = iter_start; iter < iter_stop; iter++) {
301 if (within_module_init(iter->code, mod))
302 iter->code = 0;
303 }
304}
305
306static int
307jump_label_module_notify(struct notifier_block *self, unsigned long val,
308 void *data)
309{
310 struct module *mod = data;
311 int ret = 0;
312
313 switch (val) {
314 case MODULE_STATE_COMING:
315 jump_label_lock();
316 ret = jump_label_add_module(mod);
317 if (ret)
318 jump_label_del_module(mod);
319 jump_label_unlock();
320 break;
321 case MODULE_STATE_GOING:
322 jump_label_lock();
323 jump_label_del_module(mod);
324 jump_label_unlock();
325 break;
326 case MODULE_STATE_LIVE:
327 jump_label_lock();
328 jump_label_invalidate_module_init(mod);
329 jump_label_unlock();
330 break;
331 }
332
333 return notifier_from_errno(ret);
334}
335
336struct notifier_block jump_label_module_nb = {
337 .notifier_call = jump_label_module_notify,
338 .priority = 1, /* higher than tracepoints */
339};
340
341static __init int jump_label_init_module(void)
342{
343 return register_module_notifier(&jump_label_module_nb);
344}
345early_initcall(jump_label_init_module);
346
347#endif /* CONFIG_MODULES */
348
349/***
350 * jump_label_text_reserved - check if addr range is reserved
351 * @start: start text addr
352 * @end: end text addr
353 *
354 * checks if the text addr located between @start and @end
355 * overlaps with any of the jump label patch addresses. Code
356 * that wants to modify kernel text should first verify that
357 * it does not overlap with any of the jump label addresses.
358 * Caller must hold jump_label_mutex.
359 *
360 * returns 1 if there is an overlap, 0 otherwise
361 */
362int jump_label_text_reserved(void *start, void *end)
363{
364 int ret = __jump_label_text_reserved(__start___jump_table,
365 __stop___jump_table, start, end);
366
367 if (ret)
368 return ret;
369
370#ifdef CONFIG_MODULES
371 ret = __jump_label_mod_text_reserved(start, end);
372#endif
373 return ret;
374}
375
376static void jump_label_update(struct jump_label_key *key, int enable)
377{
378 struct jump_entry *entry = key->entries, *stop = __stop___jump_table;
379
380#ifdef CONFIG_MODULES
381 struct module *mod = __module_address((jump_label_t)key);
382
383 __jump_label_mod_update(key, enable);
384
385 if (mod)
386 stop = mod->jump_entries + mod->num_jump_entries;
387#endif
388 /* if there are no users, entry can be NULL */
389 if (entry)
390 __jump_label_update(key, entry, stop, enable);
391}
392
393#endif