Blame view
kernel/jump_label.c
19.8 KB
bf5438fca jump label: Base ... |
1 2 3 4 |
/* * jump label support * * Copyright (C) 2009 Jason Baron <jbaron@redhat.com> |
90eec103b treewide: Remove ... |
5 |
* Copyright (C) 2011 Peter Zijlstra |
bf5438fca jump label: Base ... |
6 7 |
* */ |
bf5438fca jump label: Base ... |
8 9 10 11 |
#include <linux/memory.h> #include <linux/uaccess.h> #include <linux/module.h> #include <linux/list.h> |
bf5438fca jump label: Base ... |
12 13 14 |
#include <linux/slab.h> #include <linux/sort.h> #include <linux/err.h> |
c5905afb0 static keys: Intr... |
15 |
#include <linux/static_key.h> |
851cf6e7d jump_label: Split... |
16 |
#include <linux/jump_label_ratelimit.h> |
1f69bf9c6 jump_label: remov... |
17 |
#include <linux/bug.h> |
f2545b2d4 jump_label: Reord... |
18 |
#include <linux/cpu.h> |
578ae447e jump_label: Disab... |
19 |
#include <asm/sections.h> |
bf5438fca jump label: Base ... |
20 21 |
#ifdef HAVE_JUMP_LABEL |
bf5438fca jump label: Base ... |
22 23 |
/* mutex to protect coming/going of the the jump_label table */ static DEFINE_MUTEX(jump_label_mutex); |
91bad2f8d jump label: Fix d... |
24 25 26 27 28 29 30 31 32 |
void jump_label_lock(void) { mutex_lock(&jump_label_mutex); } void jump_label_unlock(void) { mutex_unlock(&jump_label_mutex); } |
bf5438fca jump label: Base ... |
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 |
static int jump_label_cmp(const void *a, const void *b) { const struct jump_entry *jea = a; const struct jump_entry *jeb = b; if (jea->key < jeb->key) return -1; if (jea->key > jeb->key) return 1; return 0; } static void |
d430d3d7e jump label: Intro... |
48 |
jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) |
bf5438fca jump label: Base ... |
49 50 51 52 53 54 55 |
{ unsigned long size; size = (((unsigned long)stop - (unsigned long)start) / sizeof(struct jump_entry)); sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL); } |
706249c22 locking/static_ke... |
56 |
static void jump_label_update(struct static_key *key); |
a1efb01fe jump_label, locki... |
57 |
|
1f69bf9c6 jump_label: remov... |
58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 |
/* * There are similar definitions for the !HAVE_JUMP_LABEL case in jump_label.h. * The use of 'atomic_read()' requires atomic.h and its problematic for some * kernel headers such as kernel.h and others. Since static_key_count() is not * used in the branch statements as it is for the !HAVE_JUMP_LABEL case its ok * to have it be a function here. Similarly, for 'static_key_enable()' and * 'static_key_disable()', which require bug.h. This should allow jump_label.h * to be included from most/all places for HAVE_JUMP_LABEL. */ int static_key_count(struct static_key *key) { /* * -1 means the first static_key_slow_inc() is in progress. * static_key_enabled() must return true, so return 1 here. */ int n = atomic_read(&key->enabled); return n >= 0 ? n : 1; } EXPORT_SYMBOL_GPL(static_key_count); |
ce48c1464 sched/core: Fix c... |
78 |
void static_key_slow_inc_cpuslocked(struct static_key *key) |
bf5438fca jump label: Base ... |
79 |
{ |
4c5ea0a9c locking/static_ke... |
80 |
int v, v1; |
5cdda5117 locking/static_ke... |
81 |
STATIC_KEY_CHECK_USE(key); |
4c5ea0a9c locking/static_ke... |
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 |
/* * Careful if we get concurrent static_key_slow_inc() calls; * later calls must wait for the first one to _finish_ the * jump_label_update() process. At the same time, however, * the jump_label_update() call below wants to see * static_key_enabled(&key) for jumps to be updated properly. * * So give a special meaning to negative key->enabled: it sends * static_key_slow_inc() down the slow path, and it is non-zero * so it counts as "enabled" in jump_label_update(). Note that * atomic_inc_unless_negative() checks >= 0, so roll our own. */ for (v = atomic_read(&key->enabled); v > 0; v = v1) { v1 = atomic_cmpxchg(&key->enabled, v, v + 1); |
8b7b41280 jump_label: Split... |
97 |
if (likely(v1 == v)) |
4c5ea0a9c locking/static_ke... |
98 99 |
return; } |
bf5438fca jump label: Base ... |
100 |
|
d430d3d7e jump label: Intro... |
101 |
jump_label_lock(); |
4c5ea0a9c locking/static_ke... |
102 103 |
if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); |
706249c22 locking/static_ke... |
104 |
jump_label_update(key); |
d0646a6f5 jump_label: Add R... |
105 106 107 108 109 |
/* * Ensure that if the above cmpxchg loop observes our positive * value, it must also observe all the text changes. */ atomic_set_release(&key->enabled, 1); |
4c5ea0a9c locking/static_ke... |
110 111 112 |
} else { atomic_inc(&key->enabled); } |
d430d3d7e jump label: Intro... |
113 |
jump_label_unlock(); |
8b7b41280 jump_label: Split... |
114 115 116 117 118 119 |
} void static_key_slow_inc(struct static_key *key) { cpus_read_lock(); static_key_slow_inc_cpuslocked(key); |
f2545b2d4 jump_label: Reord... |
120 |
cpus_read_unlock(); |
bf5438fca jump label: Base ... |
121 |
} |
c5905afb0 static keys: Intr... |
122 |
EXPORT_SYMBOL_GPL(static_key_slow_inc); |
bf5438fca jump label: Base ... |
123 |
|
5a40527f8 jump_label: Provi... |
124 |
void static_key_enable_cpuslocked(struct static_key *key) |
1dbb6704d jump_label: Fix c... |
125 |
{ |
5cdda5117 locking/static_ke... |
126 |
STATIC_KEY_CHECK_USE(key); |
5a40527f8 jump_label: Provi... |
127 |
|
1dbb6704d jump_label: Fix c... |
128 129 130 131 |
if (atomic_read(&key->enabled) > 0) { WARN_ON_ONCE(atomic_read(&key->enabled) != 1); return; } |
1dbb6704d jump_label: Fix c... |
132 133 134 135 |
jump_label_lock(); if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); jump_label_update(key); |
d0646a6f5 jump_label: Add R... |
136 137 138 139 |
/* * See static_key_slow_inc(). */ atomic_set_release(&key->enabled, 1); |
1dbb6704d jump_label: Fix c... |
140 141 |
} jump_label_unlock(); |
5a40527f8 jump_label: Provi... |
142 143 144 145 146 147 148 |
} EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked); void static_key_enable(struct static_key *key) { cpus_read_lock(); static_key_enable_cpuslocked(key); |
1dbb6704d jump_label: Fix c... |
149 150 151 |
cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_enable); |
5a40527f8 jump_label: Provi... |
152 |
void static_key_disable_cpuslocked(struct static_key *key) |
1dbb6704d jump_label: Fix c... |
153 |
{ |
5cdda5117 locking/static_ke... |
154 |
STATIC_KEY_CHECK_USE(key); |
5a40527f8 jump_label: Provi... |
155 |
|
1dbb6704d jump_label: Fix c... |
156 157 158 159 |
if (atomic_read(&key->enabled) != 1) { WARN_ON_ONCE(atomic_read(&key->enabled) != 0); return; } |
1dbb6704d jump_label: Fix c... |
160 161 162 163 |
jump_label_lock(); if (atomic_cmpxchg(&key->enabled, 1, 0)) jump_label_update(key); jump_label_unlock(); |
5a40527f8 jump_label: Provi... |
164 165 166 167 168 169 170 |
} EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked); void static_key_disable(struct static_key *key) { cpus_read_lock(); static_key_disable_cpuslocked(key); |
1dbb6704d jump_label: Fix c... |
171 172 173 |
cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_disable); |
ce48c1464 sched/core: Fix c... |
174 |
static void __static_key_slow_dec_cpuslocked(struct static_key *key, |
8b7b41280 jump_label: Split... |
175 176 |
unsigned long rate_limit, struct delayed_work *work) |
bf5438fca jump label: Base ... |
177 |
{ |
4c5ea0a9c locking/static_ke... |
178 179 180 181 182 183 184 |
/* * The negative count check is valid even when a negative * key->enabled is in use by static_key_slow_inc(); a * __static_key_slow_dec() before the first static_key_slow_inc() * returns is unbalanced, because all other static_key_slow_inc() * instances block while the update is in progress. */ |
fadf0464b jump label: Add a... |
185 186 187 188 |
if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { WARN(atomic_read(&key->enabled) < 0, "jump label: negative count! "); |
d430d3d7e jump label: Intro... |
189 |
return; |
fadf0464b jump label: Add a... |
190 |
} |
bf5438fca jump label: Base ... |
191 |
|
b20295207 perf, core: Rate ... |
192 193 194 |
if (rate_limit) { atomic_inc(&key->enabled); schedule_delayed_work(work, rate_limit); |
c5905afb0 static keys: Intr... |
195 |
} else { |
706249c22 locking/static_ke... |
196 |
jump_label_update(key); |
c5905afb0 static keys: Intr... |
197 |
} |
91bad2f8d jump label: Fix d... |
198 |
jump_label_unlock(); |
8b7b41280 jump_label: Split... |
199 200 201 202 203 204 205 |
} static void __static_key_slow_dec(struct static_key *key, unsigned long rate_limit, struct delayed_work *work) { cpus_read_lock(); |
ce48c1464 sched/core: Fix c... |
206 |
__static_key_slow_dec_cpuslocked(key, rate_limit, work); |
f2545b2d4 jump_label: Reord... |
207 |
cpus_read_unlock(); |
bf5438fca jump label: Base ... |
208 |
} |
b20295207 perf, core: Rate ... |
209 210 |
static void jump_label_update_timeout(struct work_struct *work) { |
c5905afb0 static keys: Intr... |
211 212 213 |
struct static_key_deferred *key = container_of(work, struct static_key_deferred, work.work); __static_key_slow_dec(&key->key, 0, NULL); |
b20295207 perf, core: Rate ... |
214 |
} |
c5905afb0 static keys: Intr... |
215 |
void static_key_slow_dec(struct static_key *key) |
b20295207 perf, core: Rate ... |
216 |
{ |
5cdda5117 locking/static_ke... |
217 |
STATIC_KEY_CHECK_USE(key); |
c5905afb0 static keys: Intr... |
218 |
__static_key_slow_dec(key, 0, NULL); |
b20295207 perf, core: Rate ... |
219 |
} |
c5905afb0 static keys: Intr... |
220 |
EXPORT_SYMBOL_GPL(static_key_slow_dec); |
b20295207 perf, core: Rate ... |
221 |
|
ce48c1464 sched/core: Fix c... |
222 223 224 225 226 |
void static_key_slow_dec_cpuslocked(struct static_key *key) { STATIC_KEY_CHECK_USE(key); __static_key_slow_dec_cpuslocked(key, 0, NULL); } |
c5905afb0 static keys: Intr... |
227 |
void static_key_slow_dec_deferred(struct static_key_deferred *key) |
b20295207 perf, core: Rate ... |
228 |
{ |
5cdda5117 locking/static_ke... |
229 |
STATIC_KEY_CHECK_USE(key); |
c5905afb0 static keys: Intr... |
230 |
__static_key_slow_dec(&key->key, key->timeout, &key->work); |
b20295207 perf, core: Rate ... |
231 |
} |
c5905afb0 static keys: Intr... |
232 |
EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred); |
b20295207 perf, core: Rate ... |
233 |
|
b6416e610 jump_labels: API ... |
234 235 |
void static_key_deferred_flush(struct static_key_deferred *key) { |
5cdda5117 locking/static_ke... |
236 |
STATIC_KEY_CHECK_USE(key); |
b6416e610 jump_labels: API ... |
237 238 239 |
flush_delayed_work(&key->work); } EXPORT_SYMBOL_GPL(static_key_deferred_flush); |
c5905afb0 static keys: Intr... |
240 |
void jump_label_rate_limit(struct static_key_deferred *key, |
b20295207 perf, core: Rate ... |
241 242 |
unsigned long rl) { |
5cdda5117 locking/static_ke... |
243 |
STATIC_KEY_CHECK_USE(key); |
b20295207 perf, core: Rate ... |
244 245 246 |
key->timeout = rl; INIT_DELAYED_WORK(&key->work, jump_label_update_timeout); } |
a181dc14e jump_label: Expor... |
247 |
EXPORT_SYMBOL_GPL(jump_label_rate_limit); |
b20295207 perf, core: Rate ... |
248 |
|
4c3ef6d79 jump label: Add j... |
249 250 251 252 253 254 255 256 |
static int addr_conflict(struct jump_entry *entry, void *start, void *end) { if (entry->code <= (unsigned long)end && entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start) return 1; return 0; } |
d430d3d7e jump label: Intro... |
257 258 |
static int __jump_label_text_reserved(struct jump_entry *iter_start, struct jump_entry *iter_stop, void *start, void *end) |
4c3ef6d79 jump label: Add j... |
259 |
{ |
4c3ef6d79 jump label: Add j... |
260 |
struct jump_entry *iter; |
4c3ef6d79 jump label: Add j... |
261 |
|
4c3ef6d79 jump label: Add j... |
262 263 |
iter = iter_start; while (iter < iter_stop) { |
d430d3d7e jump label: Intro... |
264 265 |
if (addr_conflict(iter, start, end)) return 1; |
4c3ef6d79 jump label: Add j... |
266 267 |
iter++; } |
d430d3d7e jump label: Intro... |
268 269 |
return 0; } |
706249c22 locking/static_ke... |
270 |
/* |
20284aa77 jump_label: add a... |
271 272 273 274 275 |
* Update code which is definitely not currently executing. * Architectures which need heavyweight synchronization to modify * running code can override this to make the non-live update case * cheaper. */ |
9cdbe1cba jump_label, x86: ... |
276 |
void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry, |
20284aa77 jump_label: add a... |
277 278 |
enum jump_label_type type) { |
706249c22 locking/static_ke... |
279 |
arch_jump_label_transform(entry, type); |
20284aa77 jump_label: add a... |
280 |
} |
706249c22 locking/static_ke... |
281 |
static inline struct jump_entry *static_key_entries(struct static_key *key) |
d430d3d7e jump label: Intro... |
282 |
{ |
3821fd35b jump_label: Reduc... |
283 284 |
WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED); return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK); |
4c3ef6d79 jump label: Add j... |
285 |
} |
706249c22 locking/static_ke... |
286 |
static inline bool static_key_type(struct static_key *key) |
c5905afb0 static keys: Intr... |
287 |
{ |
3821fd35b jump_label: Reduc... |
288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 |
return key->type & JUMP_TYPE_TRUE; } static inline bool static_key_linked(struct static_key *key) { return key->type & JUMP_TYPE_LINKED; } static inline void static_key_clear_linked(struct static_key *key) { key->type &= ~JUMP_TYPE_LINKED; } static inline void static_key_set_linked(struct static_key *key) { key->type |= JUMP_TYPE_LINKED; |
a1efb01fe jump_label, locki... |
304 |
} |
c5905afb0 static keys: Intr... |
305 |
|
7dcfd915b jump_label: Add j... |
306 307 |
static inline struct static_key *jump_entry_key(struct jump_entry *entry) { |
11276d530 locking/static_ke... |
308 309 310 311 312 313 |
return (struct static_key *)((unsigned long)entry->key & ~1UL); } static bool jump_entry_branch(struct jump_entry *entry) { return (unsigned long)entry->key & 1UL; |
7dcfd915b jump_label: Add j... |
314 |
} |
3821fd35b jump_label: Reduc... |
315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 |
/*** * A 'struct static_key' uses a union such that it either points directly * to a table of 'struct jump_entry' or to a linked list of modules which in * turn point to 'struct jump_entry' tables. * * The two lower bits of the pointer are used to keep track of which pointer * type is in use and to store the initial branch direction, we use an access * function which preserves these bits. */ static void static_key_set_entries(struct static_key *key, struct jump_entry *entries) { unsigned long type; WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK); type = key->type & JUMP_TYPE_MASK; key->entries = entries; key->type |= type; } |
706249c22 locking/static_ke... |
334 |
static enum jump_label_type jump_label_type(struct jump_entry *entry) |
a1efb01fe jump_label, locki... |
335 |
{ |
706249c22 locking/static_ke... |
336 |
struct static_key *key = jump_entry_key(entry); |
a1efb01fe jump_label, locki... |
337 |
bool enabled = static_key_enabled(key); |
11276d530 locking/static_ke... |
338 |
bool branch = jump_entry_branch(entry); |
c5905afb0 static keys: Intr... |
339 |
|
11276d530 locking/static_ke... |
340 341 |
/* See the comment in linux/jump_label.h */ return enabled ^ branch; |
c5905afb0 static keys: Intr... |
342 |
} |
706249c22 locking/static_ke... |
343 344 345 346 347 348 |
static void __jump_label_update(struct static_key *key, struct jump_entry *entry, struct jump_entry *stop) { for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { /* |
dc1dd184c jump_label: Warn ... |
349 350 |
* An entry->code of 0 indicates an entry which has been * disabled because it was in an init text area. |
706249c22 locking/static_ke... |
351 |
*/ |
dc1dd184c jump_label: Warn ... |
352 353 354 355 |
if (entry->code) { if (kernel_text_address(entry->code)) arch_jump_label_transform(entry, jump_label_type(entry)); else |
af1d830bf jump_label: Fix s... |
356 357 |
WARN_ONCE(1, "can't patch jump_label at %pS", (void *)(unsigned long)entry->code); |
dc1dd184c jump_label: Warn ... |
358 |
} |
706249c22 locking/static_ke... |
359 360 |
} } |
97ce2c88f jump-label: initi... |
361 |
void __init jump_label_init(void) |
bf5438fca jump label: Base ... |
362 |
{ |
bf5438fca jump label: Base ... |
363 364 |
struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; |
c5905afb0 static keys: Intr... |
365 |
struct static_key *key = NULL; |
bf5438fca jump label: Base ... |
366 |
struct jump_entry *iter; |
1f69bf9c6 jump_label: remov... |
367 368 369 370 371 372 373 374 |
/* * Since we are initializing the static_key.enabled field with * with the 'raw' int values (to avoid pulling in atomic.h) in * jump_label.h, let's make sure that is safe. There are only two * cases to check since we initialize to 0 or 1. */ BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0); BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1); |
e3f91083f jump_label: Make ... |
375 376 |
if (static_key_initialized) return; |
f2545b2d4 jump_label: Reord... |
377 |
cpus_read_lock(); |
91bad2f8d jump label: Fix d... |
378 |
jump_label_lock(); |
d430d3d7e jump label: Intro... |
379 380 381 |
jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { |
c5905afb0 static keys: Intr... |
382 |
struct static_key *iterk; |
37348804e jump_label: if a ... |
383 |
|
11276d530 locking/static_ke... |
384 385 386 |
/* rewrite NOPs */ if (jump_label_type(iter) == JUMP_LABEL_NOP) arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); |
7dcfd915b jump_label: Add j... |
387 |
iterk = jump_entry_key(iter); |
37348804e jump_label: if a ... |
388 |
if (iterk == key) |
d430d3d7e jump label: Intro... |
389 |
continue; |
37348804e jump_label: if a ... |
390 |
key = iterk; |
3821fd35b jump_label: Reduc... |
391 |
static_key_set_entries(key, iter); |
bf5438fca jump label: Base ... |
392 |
} |
c4b2c0c5f static_key: WARN ... |
393 |
static_key_initialized = true; |
91bad2f8d jump label: Fix d... |
394 |
jump_label_unlock(); |
f2545b2d4 jump_label: Reord... |
395 |
cpus_read_unlock(); |
bf5438fca jump label: Base ... |
396 |
} |
bf5438fca jump label: Base ... |
397 |
|
578ae447e jump_label: Disab... |
398 399 |
/* Disable any jump label entries in __init/__exit code */ void __init jump_label_invalidate_initmem(void) |
333522447 jump_label: Expli... |
400 401 402 403 404 405 |
{ struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; struct jump_entry *iter; for (iter = iter_start; iter < iter_stop; iter++) { |
578ae447e jump_label: Disab... |
406 |
if (init_section_contains((void *)(unsigned long)iter->code, 1)) |
333522447 jump_label: Expli... |
407 408 409 |
iter->code = 0; } } |
bf5438fca jump label: Base ... |
410 |
#ifdef CONFIG_MODULES |
11276d530 locking/static_ke... |
411 412 413 414 415 416 417 418 419 |
static enum jump_label_type jump_label_init_type(struct jump_entry *entry) { struct static_key *key = jump_entry_key(entry); bool type = static_key_type(key); bool branch = jump_entry_branch(entry); /* See the comment in linux/jump_label.h */ return type ^ branch; } |
c5905afb0 static keys: Intr... |
420 421 |
struct static_key_mod { struct static_key_mod *next; |
d430d3d7e jump label: Intro... |
422 423 424 |
struct jump_entry *entries; struct module *mod; }; |
3821fd35b jump_label: Reduc... |
425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 |
static inline struct static_key_mod *static_key_mod(struct static_key *key) { WARN_ON_ONCE(!(key->type & JUMP_TYPE_LINKED)); return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK); } /*** * key->type and key->next are the same via union. * This sets key->next and preserves the type bits. * * See additional comments above static_key_set_entries(). */ static void static_key_set_mod(struct static_key *key, struct static_key_mod *mod) { unsigned long type; WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK); type = key->type & JUMP_TYPE_MASK; key->next = mod; key->type |= type; } |
d430d3d7e jump label: Intro... |
447 448 449 |
static int __jump_label_mod_text_reserved(void *start, void *end) { struct module *mod; |
bdc9f3735 jump_label: disab... |
450 |
preempt_disable(); |
d430d3d7e jump label: Intro... |
451 |
mod = __module_text_address((unsigned long)start); |
bdc9f3735 jump_label: disab... |
452 453 |
WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod); preempt_enable(); |
d430d3d7e jump label: Intro... |
454 455 |
if (!mod) return 0; |
d430d3d7e jump label: Intro... |
456 457 458 459 460 |
return __jump_label_text_reserved(mod->jump_entries, mod->jump_entries + mod->num_jump_entries, start, end); } |
706249c22 locking/static_ke... |
461 |
static void __jump_label_mod_update(struct static_key *key) |
d430d3d7e jump label: Intro... |
462 |
{ |
706249c22 locking/static_ke... |
463 |
struct static_key_mod *mod; |
d430d3d7e jump label: Intro... |
464 |
|
3821fd35b jump_label: Reduc... |
465 466 467 468 469 470 471 472 473 474 |
for (mod = static_key_mod(key); mod; mod = mod->next) { struct jump_entry *stop; struct module *m; /* * NULL if the static_key is defined in a module * that does not use it */ if (!mod->entries) continue; |
7cbc5b8d4 jump_label: Check... |
475 |
|
3821fd35b jump_label: Reduc... |
476 477 478 479 480 481 |
m = mod->mod; if (!m) stop = __stop___jump_table; else stop = m->jump_entries + m->num_jump_entries; __jump_label_update(key, mod->entries, stop); |
d430d3d7e jump label: Intro... |
482 483 484 485 486 487 488 489 490 491 492 493 |
} } /*** * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop() * @mod: module to patch * * Allow for run-time selection of the optimal nops. Before the module * loads patch these with arch_get_jump_label_nop(), which is specified by * the arch specific jump label code. */ void jump_label_apply_nops(struct module *mod) |
bf5438fca jump label: Base ... |
494 |
{ |
d430d3d7e jump label: Intro... |
495 496 497 498 499 500 501 |
struct jump_entry *iter_start = mod->jump_entries; struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; struct jump_entry *iter; /* if the module doesn't have jump label entries, just return */ if (iter_start == iter_stop) return; |
11276d530 locking/static_ke... |
502 503 504 505 506 |
for (iter = iter_start; iter < iter_stop; iter++) { /* Only write NOPs for arch_branch_static(). */ if (jump_label_init_type(iter) == JUMP_LABEL_NOP) arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); } |
bf5438fca jump label: Base ... |
507 |
} |
d430d3d7e jump label: Intro... |
508 |
static int jump_label_add_module(struct module *mod) |
bf5438fca jump label: Base ... |
509 |
{ |
d430d3d7e jump label: Intro... |
510 511 512 |
struct jump_entry *iter_start = mod->jump_entries; struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; struct jump_entry *iter; |
c5905afb0 static keys: Intr... |
513 |
struct static_key *key = NULL; |
3821fd35b jump_label: Reduc... |
514 |
struct static_key_mod *jlm, *jlm2; |
bf5438fca jump label: Base ... |
515 516 |
/* if the module doesn't have jump label entries, just return */ |
d430d3d7e jump label: Intro... |
517 |
if (iter_start == iter_stop) |
bf5438fca jump label: Base ... |
518 |
return 0; |
d430d3d7e jump label: Intro... |
519 520 521 |
jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { |
c5905afb0 static keys: Intr... |
522 |
struct static_key *iterk; |
d430d3d7e jump label: Intro... |
523 |
|
7dcfd915b jump_label: Add j... |
524 |
iterk = jump_entry_key(iter); |
c5905afb0 static keys: Intr... |
525 526 |
if (iterk == key) continue; |
d430d3d7e jump label: Intro... |
527 |
|
c5905afb0 static keys: Intr... |
528 |
key = iterk; |
bed831f9a module, jump_labe... |
529 |
if (within_module(iter->key, mod)) { |
3821fd35b jump_label: Reduc... |
530 |
static_key_set_entries(key, iter); |
d430d3d7e jump label: Intro... |
531 |
continue; |
bf5438fca jump label: Base ... |
532 |
} |
c5905afb0 static keys: Intr... |
533 |
jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL); |
d430d3d7e jump label: Intro... |
534 535 |
if (!jlm) return -ENOMEM; |
3821fd35b jump_label: Reduc... |
536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 |
if (!static_key_linked(key)) { jlm2 = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL); if (!jlm2) { kfree(jlm); return -ENOMEM; } preempt_disable(); jlm2->mod = __module_address((unsigned long)key); preempt_enable(); jlm2->entries = static_key_entries(key); jlm2->next = NULL; static_key_set_mod(key, jlm2); static_key_set_linked(key); } |
d430d3d7e jump label: Intro... |
551 552 |
jlm->mod = mod; jlm->entries = iter; |
3821fd35b jump_label: Reduc... |
553 554 555 |
jlm->next = static_key_mod(key); static_key_set_mod(key, jlm); static_key_set_linked(key); |
d430d3d7e jump label: Intro... |
556 |
|
11276d530 locking/static_ke... |
557 558 |
/* Only update if we've changed from our initial state */ if (jump_label_type(iter) != jump_label_init_type(iter)) |
706249c22 locking/static_ke... |
559 |
__jump_label_update(key, iter, iter_stop); |
bf5438fca jump label: Base ... |
560 |
} |
d430d3d7e jump label: Intro... |
561 |
|
bf5438fca jump label: Base ... |
562 563 |
return 0; } |
d430d3d7e jump label: Intro... |
564 |
static void jump_label_del_module(struct module *mod) |
bf5438fca jump label: Base ... |
565 |
{ |
d430d3d7e jump label: Intro... |
566 567 568 |
struct jump_entry *iter_start = mod->jump_entries; struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; struct jump_entry *iter; |
c5905afb0 static keys: Intr... |
569 570 |
struct static_key *key = NULL; struct static_key_mod *jlm, **prev; |
bf5438fca jump label: Base ... |
571 |
|
d430d3d7e jump label: Intro... |
572 |
for (iter = iter_start; iter < iter_stop; iter++) { |
7dcfd915b jump_label: Add j... |
573 |
if (jump_entry_key(iter) == key) |
d430d3d7e jump label: Intro... |
574 |
continue; |
7dcfd915b jump_label: Add j... |
575 |
key = jump_entry_key(iter); |
d430d3d7e jump label: Intro... |
576 |
|
bed831f9a module, jump_labe... |
577 |
if (within_module(iter->key, mod)) |
d430d3d7e jump label: Intro... |
578 |
continue; |
3821fd35b jump_label: Reduc... |
579 580 581 |
/* No memory during module load */ if (WARN_ON(!static_key_linked(key))) continue; |
d430d3d7e jump label: Intro... |
582 |
prev = &key->next; |
3821fd35b jump_label: Reduc... |
583 |
jlm = static_key_mod(key); |
bf5438fca jump label: Base ... |
584 |
|
d430d3d7e jump label: Intro... |
585 586 587 588 |
while (jlm && jlm->mod != mod) { prev = &jlm->next; jlm = jlm->next; } |
3821fd35b jump_label: Reduc... |
589 590 591 592 593 594 595 |
/* No memory during module load */ if (WARN_ON(!jlm)) continue; if (prev == &key->next) static_key_set_mod(key, jlm->next); else |
d430d3d7e jump label: Intro... |
596 |
*prev = jlm->next; |
3821fd35b jump_label: Reduc... |
597 598 599 600 601 602 603 604 |
kfree(jlm); jlm = static_key_mod(key); /* if only one etry is left, fold it back into the static_key */ if (jlm->next == NULL) { static_key_set_entries(key, jlm->entries); static_key_clear_linked(key); |
d430d3d7e jump label: Intro... |
605 |
kfree(jlm); |
bf5438fca jump label: Base ... |
606 607 608 |
} } } |
333522447 jump_label: Expli... |
609 |
/* Disable any jump label entries in module init code */ |
d430d3d7e jump label: Intro... |
610 |
static void jump_label_invalidate_module_init(struct module *mod) |
b842f8faf jump label: Fix m... |
611 |
{ |
d430d3d7e jump label: Intro... |
612 613 |
struct jump_entry *iter_start = mod->jump_entries; struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; |
b842f8faf jump label: Fix m... |
614 |
struct jump_entry *iter; |
b842f8faf jump label: Fix m... |
615 |
|
d430d3d7e jump label: Intro... |
616 617 618 |
for (iter = iter_start; iter < iter_stop; iter++) { if (within_module_init(iter->code, mod)) iter->code = 0; |
b842f8faf jump label: Fix m... |
619 620 |
} } |
bf5438fca jump label: Base ... |
621 622 623 624 625 626 |
static int jump_label_module_notify(struct notifier_block *self, unsigned long val, void *data) { struct module *mod = data; int ret = 0; |
f2545b2d4 jump_label: Reord... |
627 628 |
cpus_read_lock(); jump_label_lock(); |
bf5438fca jump label: Base ... |
629 630 |
switch (val) { case MODULE_STATE_COMING: |
d430d3d7e jump label: Intro... |
631 |
ret = jump_label_add_module(mod); |
3821fd35b jump_label: Reduc... |
632 |
if (ret) { |
da260fe12 jump_label: Fix t... |
633 634 |
WARN(1, "Failed to allocate memory: jump_label may not work properly. "); |
d430d3d7e jump label: Intro... |
635 |
jump_label_del_module(mod); |
3821fd35b jump_label: Reduc... |
636 |
} |
bf5438fca jump label: Base ... |
637 638 |
break; case MODULE_STATE_GOING: |
d430d3d7e jump label: Intro... |
639 |
jump_label_del_module(mod); |
bf5438fca jump label: Base ... |
640 |
break; |
b842f8faf jump label: Fix m... |
641 |
case MODULE_STATE_LIVE: |
d430d3d7e jump label: Intro... |
642 |
jump_label_invalidate_module_init(mod); |
b842f8faf jump label: Fix m... |
643 |
break; |
bf5438fca jump label: Base ... |
644 |
} |
bf5438fca jump label: Base ... |
645 |
|
f2545b2d4 jump_label: Reord... |
646 647 |
jump_label_unlock(); cpus_read_unlock(); |
d430d3d7e jump label: Intro... |
648 |
return notifier_from_errno(ret); |
bf5438fca jump label: Base ... |
649 |
} |
885885f6b locking/static_ke... |
650 |
static struct notifier_block jump_label_module_nb = { |
bf5438fca jump label: Base ... |
651 |
.notifier_call = jump_label_module_notify, |
d430d3d7e jump label: Intro... |
652 |
.priority = 1, /* higher than tracepoints */ |
bf5438fca jump label: Base ... |
653 |
}; |
d430d3d7e jump label: Intro... |
654 |
static __init int jump_label_init_module(void) |
bf5438fca jump label: Base ... |
655 656 657 |
{ return register_module_notifier(&jump_label_module_nb); } |
d430d3d7e jump label: Intro... |
658 |
early_initcall(jump_label_init_module); |
bf5438fca jump label: Base ... |
659 660 |
#endif /* CONFIG_MODULES */ |
d430d3d7e jump label: Intro... |
661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 |
/*** * jump_label_text_reserved - check if addr range is reserved * @start: start text addr * @end: end text addr * * checks if the text addr located between @start and @end * overlaps with any of the jump label patch addresses. Code * that wants to modify kernel text should first verify that * it does not overlap with any of the jump label addresses. * Caller must hold jump_label_mutex. * * returns 1 if there is an overlap, 0 otherwise */ int jump_label_text_reserved(void *start, void *end) { int ret = __jump_label_text_reserved(__start___jump_table, __stop___jump_table, start, end); if (ret) return ret; #ifdef CONFIG_MODULES ret = __jump_label_mod_text_reserved(start, end); #endif return ret; } |
706249c22 locking/static_ke... |
687 |
static void jump_label_update(struct static_key *key) |
d430d3d7e jump label: Intro... |
688 |
{ |
c5905afb0 static keys: Intr... |
689 |
struct jump_entry *stop = __stop___jump_table; |
3821fd35b jump_label: Reduc... |
690 |
struct jump_entry *entry; |
d430d3d7e jump label: Intro... |
691 |
#ifdef CONFIG_MODULES |
bed831f9a module, jump_labe... |
692 |
struct module *mod; |
140fe3b1a jump_label: Fix j... |
693 |
|
3821fd35b jump_label: Reduc... |
694 695 696 697 |
if (static_key_linked(key)) { __jump_label_mod_update(key); return; } |
140fe3b1a jump_label: Fix j... |
698 |
|
bed831f9a module, jump_labe... |
699 700 |
preempt_disable(); mod = __module_address((unsigned long)key); |
140fe3b1a jump_label: Fix j... |
701 702 |
if (mod) stop = mod->jump_entries + mod->num_jump_entries; |
bed831f9a module, jump_labe... |
703 |
preempt_enable(); |
d430d3d7e jump label: Intro... |
704 |
#endif |
3821fd35b jump_label: Reduc... |
705 |
entry = static_key_entries(key); |
140fe3b1a jump_label: Fix j... |
706 707 |
/* if there are no users, entry can be NULL */ if (entry) |
706249c22 locking/static_ke... |
708 |
__jump_label_update(key, entry, stop); |
d430d3d7e jump label: Intro... |
709 |
} |
1987c947d locking/static_ke... |
710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 |
#ifdef CONFIG_STATIC_KEYS_SELFTEST static DEFINE_STATIC_KEY_TRUE(sk_true); static DEFINE_STATIC_KEY_FALSE(sk_false); static __init int jump_label_test(void) { int i; for (i = 0; i < 2; i++) { WARN_ON(static_key_enabled(&sk_true.key) != true); WARN_ON(static_key_enabled(&sk_false.key) != false); WARN_ON(!static_branch_likely(&sk_true)); WARN_ON(!static_branch_unlikely(&sk_true)); WARN_ON(static_branch_likely(&sk_false)); WARN_ON(static_branch_unlikely(&sk_false)); static_branch_disable(&sk_true); static_branch_enable(&sk_false); WARN_ON(static_key_enabled(&sk_true.key) == true); WARN_ON(static_key_enabled(&sk_false.key) == false); WARN_ON(static_branch_likely(&sk_true)); WARN_ON(static_branch_unlikely(&sk_true)); WARN_ON(!static_branch_likely(&sk_false)); WARN_ON(!static_branch_unlikely(&sk_false)); static_branch_enable(&sk_true); static_branch_disable(&sk_false); } return 0; } |
92ee46efe jump_label: Invok... |
744 |
early_initcall(jump_label_test); |
1987c947d locking/static_ke... |
745 746 747 |
#endif /* STATIC_KEYS_SELFTEST */ #endif /* HAVE_JUMP_LABEL */ |