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Commit | Line | Data |
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bf5438fc JB |
1 | /* |
2 | * jump label support | |
3 | * | |
4 | * Copyright (C) 2009 Jason Baron <jbaron@redhat.com> | |
90eec103 | 5 | * Copyright (C) 2011 Peter Zijlstra |
bf5438fc JB |
6 | * |
7 | */ | |
bf5438fc JB |
8 | #include <linux/memory.h> |
9 | #include <linux/uaccess.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/list.h> | |
bf5438fc JB |
12 | #include <linux/slab.h> |
13 | #include <linux/sort.h> | |
14 | #include <linux/err.h> | |
c5905afb | 15 | #include <linux/static_key.h> |
851cf6e7 | 16 | #include <linux/jump_label_ratelimit.h> |
1f69bf9c | 17 | #include <linux/bug.h> |
bf5438fc JB |
18 | |
19 | #ifdef HAVE_JUMP_LABEL | |
20 | ||
bf5438fc JB |
21 | /* mutex to protect coming/going of the the jump_label table */ |
22 | static DEFINE_MUTEX(jump_label_mutex); | |
23 | ||
91bad2f8 JB |
24 | void jump_label_lock(void) |
25 | { | |
26 | mutex_lock(&jump_label_mutex); | |
27 | } | |
28 | ||
29 | void jump_label_unlock(void) | |
30 | { | |
31 | mutex_unlock(&jump_label_mutex); | |
32 | } | |
33 | ||
bf5438fc JB |
34 | static int jump_label_cmp(const void *a, const void *b) |
35 | { | |
36 | const struct jump_entry *jea = a; | |
37 | const struct jump_entry *jeb = b; | |
38 | ||
39 | if (jea->key < jeb->key) | |
40 | return -1; | |
41 | ||
42 | if (jea->key > jeb->key) | |
43 | return 1; | |
44 | ||
45 | return 0; | |
46 | } | |
47 | ||
48 | static void | |
d430d3d7 | 49 | jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) |
bf5438fc JB |
50 | { |
51 | unsigned long size; | |
52 | ||
53 | size = (((unsigned long)stop - (unsigned long)start) | |
54 | / sizeof(struct jump_entry)); | |
55 | sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL); | |
56 | } | |
57 | ||
706249c2 | 58 | static void jump_label_update(struct static_key *key); |
a1efb01f | 59 | |
1f69bf9c JB |
60 | /* |
61 | * There are similar definitions for the !HAVE_JUMP_LABEL case in jump_label.h. | |
62 | * The use of 'atomic_read()' requires atomic.h and its problematic for some | |
63 | * kernel headers such as kernel.h and others. Since static_key_count() is not | |
64 | * used in the branch statements as it is for the !HAVE_JUMP_LABEL case its ok | |
65 | * to have it be a function here. Similarly, for 'static_key_enable()' and | |
66 | * 'static_key_disable()', which require bug.h. This should allow jump_label.h | |
67 | * to be included from most/all places for HAVE_JUMP_LABEL. | |
68 | */ | |
69 | int static_key_count(struct static_key *key) | |
70 | { | |
71 | /* | |
72 | * -1 means the first static_key_slow_inc() is in progress. | |
73 | * static_key_enabled() must return true, so return 1 here. | |
74 | */ | |
75 | int n = atomic_read(&key->enabled); | |
76 | ||
77 | return n >= 0 ? n : 1; | |
78 | } | |
79 | EXPORT_SYMBOL_GPL(static_key_count); | |
80 | ||
81 | void static_key_enable(struct static_key *key) | |
82 | { | |
83 | int count = static_key_count(key); | |
84 | ||
85 | WARN_ON_ONCE(count < 0 || count > 1); | |
86 | ||
87 | if (!count) | |
88 | static_key_slow_inc(key); | |
89 | } | |
90 | EXPORT_SYMBOL_GPL(static_key_enable); | |
91 | ||
92 | void static_key_disable(struct static_key *key) | |
93 | { | |
94 | int count = static_key_count(key); | |
95 | ||
96 | WARN_ON_ONCE(count < 0 || count > 1); | |
97 | ||
98 | if (count) | |
99 | static_key_slow_dec(key); | |
100 | } | |
101 | EXPORT_SYMBOL_GPL(static_key_disable); | |
102 | ||
c5905afb | 103 | void static_key_slow_inc(struct static_key *key) |
bf5438fc | 104 | { |
4c5ea0a9 PB |
105 | int v, v1; |
106 | ||
c4b2c0c5 | 107 | STATIC_KEY_CHECK_USE(); |
4c5ea0a9 PB |
108 | |
109 | /* | |
110 | * Careful if we get concurrent static_key_slow_inc() calls; | |
111 | * later calls must wait for the first one to _finish_ the | |
112 | * jump_label_update() process. At the same time, however, | |
113 | * the jump_label_update() call below wants to see | |
114 | * static_key_enabled(&key) for jumps to be updated properly. | |
115 | * | |
116 | * So give a special meaning to negative key->enabled: it sends | |
117 | * static_key_slow_inc() down the slow path, and it is non-zero | |
118 | * so it counts as "enabled" in jump_label_update(). Note that | |
119 | * atomic_inc_unless_negative() checks >= 0, so roll our own. | |
120 | */ | |
121 | for (v = atomic_read(&key->enabled); v > 0; v = v1) { | |
122 | v1 = atomic_cmpxchg(&key->enabled, v, v + 1); | |
123 | if (likely(v1 == v)) | |
124 | return; | |
125 | } | |
bf5438fc | 126 | |
d430d3d7 | 127 | jump_label_lock(); |
4c5ea0a9 PB |
128 | if (atomic_read(&key->enabled) == 0) { |
129 | atomic_set(&key->enabled, -1); | |
706249c2 | 130 | jump_label_update(key); |
4c5ea0a9 PB |
131 | atomic_set(&key->enabled, 1); |
132 | } else { | |
133 | atomic_inc(&key->enabled); | |
134 | } | |
d430d3d7 | 135 | jump_label_unlock(); |
bf5438fc | 136 | } |
c5905afb | 137 | EXPORT_SYMBOL_GPL(static_key_slow_inc); |
bf5438fc | 138 | |
c5905afb | 139 | static void __static_key_slow_dec(struct static_key *key, |
b2029520 | 140 | unsigned long rate_limit, struct delayed_work *work) |
bf5438fc | 141 | { |
4c5ea0a9 PB |
142 | /* |
143 | * The negative count check is valid even when a negative | |
144 | * key->enabled is in use by static_key_slow_inc(); a | |
145 | * __static_key_slow_dec() before the first static_key_slow_inc() | |
146 | * returns is unbalanced, because all other static_key_slow_inc() | |
147 | * instances block while the update is in progress. | |
148 | */ | |
fadf0464 JB |
149 | if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { |
150 | WARN(atomic_read(&key->enabled) < 0, | |
151 | "jump label: negative count!\n"); | |
d430d3d7 | 152 | return; |
fadf0464 | 153 | } |
bf5438fc | 154 | |
b2029520 GN |
155 | if (rate_limit) { |
156 | atomic_inc(&key->enabled); | |
157 | schedule_delayed_work(work, rate_limit); | |
c5905afb | 158 | } else { |
706249c2 | 159 | jump_label_update(key); |
c5905afb | 160 | } |
91bad2f8 | 161 | jump_label_unlock(); |
bf5438fc JB |
162 | } |
163 | ||
b2029520 GN |
164 | static void jump_label_update_timeout(struct work_struct *work) |
165 | { | |
c5905afb IM |
166 | struct static_key_deferred *key = |
167 | container_of(work, struct static_key_deferred, work.work); | |
168 | __static_key_slow_dec(&key->key, 0, NULL); | |
b2029520 GN |
169 | } |
170 | ||
c5905afb | 171 | void static_key_slow_dec(struct static_key *key) |
b2029520 | 172 | { |
c4b2c0c5 | 173 | STATIC_KEY_CHECK_USE(); |
c5905afb | 174 | __static_key_slow_dec(key, 0, NULL); |
b2029520 | 175 | } |
c5905afb | 176 | EXPORT_SYMBOL_GPL(static_key_slow_dec); |
b2029520 | 177 | |
c5905afb | 178 | void static_key_slow_dec_deferred(struct static_key_deferred *key) |
b2029520 | 179 | { |
c4b2c0c5 | 180 | STATIC_KEY_CHECK_USE(); |
c5905afb | 181 | __static_key_slow_dec(&key->key, key->timeout, &key->work); |
b2029520 | 182 | } |
c5905afb | 183 | EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred); |
b2029520 | 184 | |
c5905afb | 185 | void jump_label_rate_limit(struct static_key_deferred *key, |
b2029520 GN |
186 | unsigned long rl) |
187 | { | |
c4b2c0c5 | 188 | STATIC_KEY_CHECK_USE(); |
b2029520 GN |
189 | key->timeout = rl; |
190 | INIT_DELAYED_WORK(&key->work, jump_label_update_timeout); | |
191 | } | |
a181dc14 | 192 | EXPORT_SYMBOL_GPL(jump_label_rate_limit); |
b2029520 | 193 | |
4c3ef6d7 JB |
194 | static int addr_conflict(struct jump_entry *entry, void *start, void *end) |
195 | { | |
196 | if (entry->code <= (unsigned long)end && | |
197 | entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start) | |
198 | return 1; | |
199 | ||
200 | return 0; | |
201 | } | |
202 | ||
d430d3d7 JB |
203 | static int __jump_label_text_reserved(struct jump_entry *iter_start, |
204 | struct jump_entry *iter_stop, void *start, void *end) | |
4c3ef6d7 | 205 | { |
4c3ef6d7 | 206 | struct jump_entry *iter; |
4c3ef6d7 | 207 | |
4c3ef6d7 JB |
208 | iter = iter_start; |
209 | while (iter < iter_stop) { | |
d430d3d7 JB |
210 | if (addr_conflict(iter, start, end)) |
211 | return 1; | |
4c3ef6d7 JB |
212 | iter++; |
213 | } | |
214 | ||
d430d3d7 JB |
215 | return 0; |
216 | } | |
217 | ||
706249c2 | 218 | /* |
20284aa7 JF |
219 | * Update code which is definitely not currently executing. |
220 | * Architectures which need heavyweight synchronization to modify | |
221 | * running code can override this to make the non-live update case | |
222 | * cheaper. | |
223 | */ | |
9cdbe1cb | 224 | void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry, |
20284aa7 JF |
225 | enum jump_label_type type) |
226 | { | |
706249c2 | 227 | arch_jump_label_transform(entry, type); |
20284aa7 JF |
228 | } |
229 | ||
706249c2 | 230 | static inline struct jump_entry *static_key_entries(struct static_key *key) |
d430d3d7 | 231 | { |
706249c2 | 232 | return (struct jump_entry *)((unsigned long)key->entries & ~JUMP_TYPE_MASK); |
4c3ef6d7 JB |
233 | } |
234 | ||
706249c2 | 235 | static inline bool static_key_type(struct static_key *key) |
c5905afb | 236 | { |
706249c2 | 237 | return (unsigned long)key->entries & JUMP_TYPE_MASK; |
a1efb01f | 238 | } |
c5905afb | 239 | |
7dcfd915 PZ |
240 | static inline struct static_key *jump_entry_key(struct jump_entry *entry) |
241 | { | |
11276d53 PZ |
242 | return (struct static_key *)((unsigned long)entry->key & ~1UL); |
243 | } | |
244 | ||
245 | static bool jump_entry_branch(struct jump_entry *entry) | |
246 | { | |
247 | return (unsigned long)entry->key & 1UL; | |
7dcfd915 PZ |
248 | } |
249 | ||
706249c2 | 250 | static enum jump_label_type jump_label_type(struct jump_entry *entry) |
a1efb01f | 251 | { |
706249c2 | 252 | struct static_key *key = jump_entry_key(entry); |
a1efb01f | 253 | bool enabled = static_key_enabled(key); |
11276d53 | 254 | bool branch = jump_entry_branch(entry); |
c5905afb | 255 | |
11276d53 PZ |
256 | /* See the comment in linux/jump_label.h */ |
257 | return enabled ^ branch; | |
c5905afb IM |
258 | } |
259 | ||
706249c2 PZ |
260 | static void __jump_label_update(struct static_key *key, |
261 | struct jump_entry *entry, | |
262 | struct jump_entry *stop) | |
263 | { | |
264 | for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { | |
265 | /* | |
266 | * entry->code set to 0 invalidates module init text sections | |
267 | * kernel_text_address() verifies we are not in core kernel | |
268 | * init code, see jump_label_invalidate_module_init(). | |
269 | */ | |
270 | if (entry->code && kernel_text_address(entry->code)) | |
271 | arch_jump_label_transform(entry, jump_label_type(entry)); | |
272 | } | |
273 | } | |
274 | ||
97ce2c88 | 275 | void __init jump_label_init(void) |
bf5438fc | 276 | { |
bf5438fc JB |
277 | struct jump_entry *iter_start = __start___jump_table; |
278 | struct jump_entry *iter_stop = __stop___jump_table; | |
c5905afb | 279 | struct static_key *key = NULL; |
bf5438fc JB |
280 | struct jump_entry *iter; |
281 | ||
1f69bf9c JB |
282 | /* |
283 | * Since we are initializing the static_key.enabled field with | |
284 | * with the 'raw' int values (to avoid pulling in atomic.h) in | |
285 | * jump_label.h, let's make sure that is safe. There are only two | |
286 | * cases to check since we initialize to 0 or 1. | |
287 | */ | |
288 | BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0); | |
289 | BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1); | |
290 | ||
91bad2f8 | 291 | jump_label_lock(); |
d430d3d7 JB |
292 | jump_label_sort_entries(iter_start, iter_stop); |
293 | ||
294 | for (iter = iter_start; iter < iter_stop; iter++) { | |
c5905afb | 295 | struct static_key *iterk; |
37348804 | 296 | |
11276d53 PZ |
297 | /* rewrite NOPs */ |
298 | if (jump_label_type(iter) == JUMP_LABEL_NOP) | |
299 | arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); | |
300 | ||
7dcfd915 | 301 | iterk = jump_entry_key(iter); |
37348804 | 302 | if (iterk == key) |
d430d3d7 JB |
303 | continue; |
304 | ||
37348804 | 305 | key = iterk; |
c5905afb IM |
306 | /* |
307 | * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH. | |
308 | */ | |
309 | *((unsigned long *)&key->entries) += (unsigned long)iter; | |
d430d3d7 JB |
310 | #ifdef CONFIG_MODULES |
311 | key->next = NULL; | |
312 | #endif | |
bf5438fc | 313 | } |
c4b2c0c5 | 314 | static_key_initialized = true; |
91bad2f8 | 315 | jump_label_unlock(); |
bf5438fc | 316 | } |
bf5438fc JB |
317 | |
318 | #ifdef CONFIG_MODULES | |
319 | ||
11276d53 PZ |
320 | static enum jump_label_type jump_label_init_type(struct jump_entry *entry) |
321 | { | |
322 | struct static_key *key = jump_entry_key(entry); | |
323 | bool type = static_key_type(key); | |
324 | bool branch = jump_entry_branch(entry); | |
325 | ||
326 | /* See the comment in linux/jump_label.h */ | |
327 | return type ^ branch; | |
328 | } | |
329 | ||
c5905afb IM |
330 | struct static_key_mod { |
331 | struct static_key_mod *next; | |
d430d3d7 JB |
332 | struct jump_entry *entries; |
333 | struct module *mod; | |
334 | }; | |
335 | ||
336 | static int __jump_label_mod_text_reserved(void *start, void *end) | |
337 | { | |
338 | struct module *mod; | |
339 | ||
bdc9f373 | 340 | preempt_disable(); |
d430d3d7 | 341 | mod = __module_text_address((unsigned long)start); |
bdc9f373 RR |
342 | WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod); |
343 | preempt_enable(); | |
344 | ||
d430d3d7 JB |
345 | if (!mod) |
346 | return 0; | |
347 | ||
d430d3d7 JB |
348 | |
349 | return __jump_label_text_reserved(mod->jump_entries, | |
350 | mod->jump_entries + mod->num_jump_entries, | |
351 | start, end); | |
352 | } | |
353 | ||
706249c2 | 354 | static void __jump_label_mod_update(struct static_key *key) |
d430d3d7 | 355 | { |
706249c2 | 356 | struct static_key_mod *mod; |
d430d3d7 | 357 | |
706249c2 | 358 | for (mod = key->next; mod; mod = mod->next) { |
7cbc5b8d JO |
359 | struct module *m = mod->mod; |
360 | ||
361 | __jump_label_update(key, mod->entries, | |
706249c2 | 362 | m->jump_entries + m->num_jump_entries); |
d430d3d7 JB |
363 | } |
364 | } | |
365 | ||
366 | /*** | |
367 | * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop() | |
368 | * @mod: module to patch | |
369 | * | |
370 | * Allow for run-time selection of the optimal nops. Before the module | |
371 | * loads patch these with arch_get_jump_label_nop(), which is specified by | |
372 | * the arch specific jump label code. | |
373 | */ | |
374 | void jump_label_apply_nops(struct module *mod) | |
bf5438fc | 375 | { |
d430d3d7 JB |
376 | struct jump_entry *iter_start = mod->jump_entries; |
377 | struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; | |
378 | struct jump_entry *iter; | |
379 | ||
380 | /* if the module doesn't have jump label entries, just return */ | |
381 | if (iter_start == iter_stop) | |
382 | return; | |
383 | ||
11276d53 PZ |
384 | for (iter = iter_start; iter < iter_stop; iter++) { |
385 | /* Only write NOPs for arch_branch_static(). */ | |
386 | if (jump_label_init_type(iter) == JUMP_LABEL_NOP) | |
387 | arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); | |
388 | } | |
bf5438fc JB |
389 | } |
390 | ||
d430d3d7 | 391 | static int jump_label_add_module(struct module *mod) |
bf5438fc | 392 | { |
d430d3d7 JB |
393 | struct jump_entry *iter_start = mod->jump_entries; |
394 | struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; | |
395 | struct jump_entry *iter; | |
c5905afb IM |
396 | struct static_key *key = NULL; |
397 | struct static_key_mod *jlm; | |
bf5438fc JB |
398 | |
399 | /* if the module doesn't have jump label entries, just return */ | |
d430d3d7 | 400 | if (iter_start == iter_stop) |
bf5438fc JB |
401 | return 0; |
402 | ||
d430d3d7 JB |
403 | jump_label_sort_entries(iter_start, iter_stop); |
404 | ||
405 | for (iter = iter_start; iter < iter_stop; iter++) { | |
c5905afb | 406 | struct static_key *iterk; |
d430d3d7 | 407 | |
7dcfd915 | 408 | iterk = jump_entry_key(iter); |
c5905afb IM |
409 | if (iterk == key) |
410 | continue; | |
d430d3d7 | 411 | |
c5905afb | 412 | key = iterk; |
bed831f9 | 413 | if (within_module(iter->key, mod)) { |
c5905afb IM |
414 | /* |
415 | * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH. | |
416 | */ | |
417 | *((unsigned long *)&key->entries) += (unsigned long)iter; | |
d430d3d7 JB |
418 | key->next = NULL; |
419 | continue; | |
bf5438fc | 420 | } |
c5905afb | 421 | jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL); |
d430d3d7 JB |
422 | if (!jlm) |
423 | return -ENOMEM; | |
d430d3d7 JB |
424 | jlm->mod = mod; |
425 | jlm->entries = iter; | |
426 | jlm->next = key->next; | |
427 | key->next = jlm; | |
428 | ||
11276d53 PZ |
429 | /* Only update if we've changed from our initial state */ |
430 | if (jump_label_type(iter) != jump_label_init_type(iter)) | |
706249c2 | 431 | __jump_label_update(key, iter, iter_stop); |
bf5438fc | 432 | } |
d430d3d7 | 433 | |
bf5438fc JB |
434 | return 0; |
435 | } | |
436 | ||
d430d3d7 | 437 | static void jump_label_del_module(struct module *mod) |
bf5438fc | 438 | { |
d430d3d7 JB |
439 | struct jump_entry *iter_start = mod->jump_entries; |
440 | struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; | |
441 | struct jump_entry *iter; | |
c5905afb IM |
442 | struct static_key *key = NULL; |
443 | struct static_key_mod *jlm, **prev; | |
bf5438fc | 444 | |
d430d3d7 | 445 | for (iter = iter_start; iter < iter_stop; iter++) { |
7dcfd915 | 446 | if (jump_entry_key(iter) == key) |
d430d3d7 JB |
447 | continue; |
448 | ||
7dcfd915 | 449 | key = jump_entry_key(iter); |
d430d3d7 | 450 | |
bed831f9 | 451 | if (within_module(iter->key, mod)) |
d430d3d7 JB |
452 | continue; |
453 | ||
454 | prev = &key->next; | |
455 | jlm = key->next; | |
bf5438fc | 456 | |
d430d3d7 JB |
457 | while (jlm && jlm->mod != mod) { |
458 | prev = &jlm->next; | |
459 | jlm = jlm->next; | |
460 | } | |
461 | ||
462 | if (jlm) { | |
463 | *prev = jlm->next; | |
464 | kfree(jlm); | |
bf5438fc JB |
465 | } |
466 | } | |
467 | } | |
468 | ||
d430d3d7 | 469 | static void jump_label_invalidate_module_init(struct module *mod) |
b842f8fa | 470 | { |
d430d3d7 JB |
471 | struct jump_entry *iter_start = mod->jump_entries; |
472 | struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; | |
b842f8fa | 473 | struct jump_entry *iter; |
b842f8fa | 474 | |
d430d3d7 JB |
475 | for (iter = iter_start; iter < iter_stop; iter++) { |
476 | if (within_module_init(iter->code, mod)) | |
477 | iter->code = 0; | |
b842f8fa JB |
478 | } |
479 | } | |
480 | ||
bf5438fc JB |
481 | static int |
482 | jump_label_module_notify(struct notifier_block *self, unsigned long val, | |
483 | void *data) | |
484 | { | |
485 | struct module *mod = data; | |
486 | int ret = 0; | |
487 | ||
488 | switch (val) { | |
489 | case MODULE_STATE_COMING: | |
91bad2f8 | 490 | jump_label_lock(); |
d430d3d7 | 491 | ret = jump_label_add_module(mod); |
bf5438fc | 492 | if (ret) |
d430d3d7 | 493 | jump_label_del_module(mod); |
91bad2f8 | 494 | jump_label_unlock(); |
bf5438fc JB |
495 | break; |
496 | case MODULE_STATE_GOING: | |
91bad2f8 | 497 | jump_label_lock(); |
d430d3d7 | 498 | jump_label_del_module(mod); |
91bad2f8 | 499 | jump_label_unlock(); |
bf5438fc | 500 | break; |
b842f8fa | 501 | case MODULE_STATE_LIVE: |
91bad2f8 | 502 | jump_label_lock(); |
d430d3d7 | 503 | jump_label_invalidate_module_init(mod); |
91bad2f8 | 504 | jump_label_unlock(); |
b842f8fa | 505 | break; |
bf5438fc | 506 | } |
bf5438fc | 507 | |
d430d3d7 | 508 | return notifier_from_errno(ret); |
bf5438fc JB |
509 | } |
510 | ||
885885f6 | 511 | static struct notifier_block jump_label_module_nb = { |
bf5438fc | 512 | .notifier_call = jump_label_module_notify, |
d430d3d7 | 513 | .priority = 1, /* higher than tracepoints */ |
bf5438fc JB |
514 | }; |
515 | ||
d430d3d7 | 516 | static __init int jump_label_init_module(void) |
bf5438fc JB |
517 | { |
518 | return register_module_notifier(&jump_label_module_nb); | |
519 | } | |
d430d3d7 | 520 | early_initcall(jump_label_init_module); |
bf5438fc JB |
521 | |
522 | #endif /* CONFIG_MODULES */ | |
523 | ||
d430d3d7 JB |
524 | /*** |
525 | * jump_label_text_reserved - check if addr range is reserved | |
526 | * @start: start text addr | |
527 | * @end: end text addr | |
528 | * | |
529 | * checks if the text addr located between @start and @end | |
530 | * overlaps with any of the jump label patch addresses. Code | |
531 | * that wants to modify kernel text should first verify that | |
532 | * it does not overlap with any of the jump label addresses. | |
533 | * Caller must hold jump_label_mutex. | |
534 | * | |
535 | * returns 1 if there is an overlap, 0 otherwise | |
536 | */ | |
537 | int jump_label_text_reserved(void *start, void *end) | |
538 | { | |
539 | int ret = __jump_label_text_reserved(__start___jump_table, | |
540 | __stop___jump_table, start, end); | |
541 | ||
542 | if (ret) | |
543 | return ret; | |
544 | ||
545 | #ifdef CONFIG_MODULES | |
546 | ret = __jump_label_mod_text_reserved(start, end); | |
547 | #endif | |
548 | return ret; | |
549 | } | |
550 | ||
706249c2 | 551 | static void jump_label_update(struct static_key *key) |
d430d3d7 | 552 | { |
c5905afb | 553 | struct jump_entry *stop = __stop___jump_table; |
a1efb01f | 554 | struct jump_entry *entry = static_key_entries(key); |
d430d3d7 | 555 | #ifdef CONFIG_MODULES |
bed831f9 | 556 | struct module *mod; |
140fe3b1 | 557 | |
706249c2 | 558 | __jump_label_mod_update(key); |
140fe3b1 | 559 | |
bed831f9 PZ |
560 | preempt_disable(); |
561 | mod = __module_address((unsigned long)key); | |
140fe3b1 XG |
562 | if (mod) |
563 | stop = mod->jump_entries + mod->num_jump_entries; | |
bed831f9 | 564 | preempt_enable(); |
d430d3d7 | 565 | #endif |
140fe3b1 XG |
566 | /* if there are no users, entry can be NULL */ |
567 | if (entry) | |
706249c2 | 568 | __jump_label_update(key, entry, stop); |
d430d3d7 JB |
569 | } |
570 | ||
1987c947 PZ |
571 | #ifdef CONFIG_STATIC_KEYS_SELFTEST |
572 | static DEFINE_STATIC_KEY_TRUE(sk_true); | |
573 | static DEFINE_STATIC_KEY_FALSE(sk_false); | |
574 | ||
575 | static __init int jump_label_test(void) | |
576 | { | |
577 | int i; | |
578 | ||
579 | for (i = 0; i < 2; i++) { | |
580 | WARN_ON(static_key_enabled(&sk_true.key) != true); | |
581 | WARN_ON(static_key_enabled(&sk_false.key) != false); | |
582 | ||
583 | WARN_ON(!static_branch_likely(&sk_true)); | |
584 | WARN_ON(!static_branch_unlikely(&sk_true)); | |
585 | WARN_ON(static_branch_likely(&sk_false)); | |
586 | WARN_ON(static_branch_unlikely(&sk_false)); | |
587 | ||
588 | static_branch_disable(&sk_true); | |
589 | static_branch_enable(&sk_false); | |
590 | ||
591 | WARN_ON(static_key_enabled(&sk_true.key) == true); | |
592 | WARN_ON(static_key_enabled(&sk_false.key) == false); | |
593 | ||
594 | WARN_ON(static_branch_likely(&sk_true)); | |
595 | WARN_ON(static_branch_unlikely(&sk_true)); | |
596 | WARN_ON(!static_branch_likely(&sk_false)); | |
597 | WARN_ON(!static_branch_unlikely(&sk_false)); | |
598 | ||
599 | static_branch_enable(&sk_true); | |
600 | static_branch_disable(&sk_false); | |
601 | } | |
602 | ||
603 | return 0; | |
604 | } | |
605 | late_initcall(jump_label_test); | |
606 | #endif /* STATIC_KEYS_SELFTEST */ | |
607 | ||
608 | #endif /* HAVE_JUMP_LABEL */ |