diff options
Diffstat (limited to 'kernel/jump_label.c')
| -rw-r--r-- | kernel/jump_label.c | 128 |
1 files changed, 91 insertions, 37 deletions
diff --git a/kernel/jump_label.c b/kernel/jump_label.c index bad96b476eb6..df3008419a1d 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * jump label support * @@ -36,12 +37,26 @@ static int jump_label_cmp(const void *a, const void *b) const struct jump_entry *jea = a; const struct jump_entry *jeb = b; + /* + * Entrires are sorted by key. + */ if (jump_entry_key(jea) < jump_entry_key(jeb)) return -1; if (jump_entry_key(jea) > jump_entry_key(jeb)) return 1; + /* + * In the batching mode, entries should also be sorted by the code + * inside the already sorted list of entries, enabling a bsearch in + * the vector. + */ + if (jump_entry_code(jea) < jump_entry_code(jeb)) + return -1; + + if (jump_entry_code(jea) > jump_entry_code(jeb)) + return 1; + return 0; } @@ -202,11 +217,13 @@ void static_key_disable(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_disable); -static void __static_key_slow_dec_cpuslocked(struct static_key *key, - unsigned long rate_limit, - struct delayed_work *work) +static bool static_key_slow_try_dec(struct static_key *key) { - lockdep_assert_cpus_held(); + int val; + + val = atomic_fetch_add_unless(&key->enabled, -1, 1); + if (val == 1) + return false; /* * The negative count check is valid even when a negative @@ -215,63 +232,70 @@ static void __static_key_slow_dec_cpuslocked(struct static_key *key, * returns is unbalanced, because all other static_key_slow_inc() * instances block while the update is in progress. */ - if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { - WARN(atomic_read(&key->enabled) < 0, - "jump label: negative count!\n"); + WARN(val < 0, "jump label: negative count!\n"); + return true; +} + +static void __static_key_slow_dec_cpuslocked(struct static_key *key) +{ + lockdep_assert_cpus_held(); + + if (static_key_slow_try_dec(key)) return; - } - if (rate_limit) { - atomic_inc(&key->enabled); - schedule_delayed_work(work, rate_limit); - } else { + jump_label_lock(); + if (atomic_dec_and_test(&key->enabled)) jump_label_update(key); - } jump_label_unlock(); } -static void __static_key_slow_dec(struct static_key *key, - unsigned long rate_limit, - struct delayed_work *work) +static void __static_key_slow_dec(struct static_key *key) { cpus_read_lock(); - __static_key_slow_dec_cpuslocked(key, rate_limit, work); + __static_key_slow_dec_cpuslocked(key); cpus_read_unlock(); } -static void jump_label_update_timeout(struct work_struct *work) +void jump_label_update_timeout(struct work_struct *work) { struct static_key_deferred *key = container_of(work, struct static_key_deferred, work.work); - __static_key_slow_dec(&key->key, 0, NULL); + __static_key_slow_dec(&key->key); } +EXPORT_SYMBOL_GPL(jump_label_update_timeout); void static_key_slow_dec(struct static_key *key) { STATIC_KEY_CHECK_USE(key); - __static_key_slow_dec(key, 0, NULL); + __static_key_slow_dec(key); } EXPORT_SYMBOL_GPL(static_key_slow_dec); void static_key_slow_dec_cpuslocked(struct static_key *key) { STATIC_KEY_CHECK_USE(key); - __static_key_slow_dec_cpuslocked(key, 0, NULL); + __static_key_slow_dec_cpuslocked(key); } -void static_key_slow_dec_deferred(struct static_key_deferred *key) +void __static_key_slow_dec_deferred(struct static_key *key, + struct delayed_work *work, + unsigned long timeout) { STATIC_KEY_CHECK_USE(key); - __static_key_slow_dec(&key->key, key->timeout, &key->work); + + if (static_key_slow_try_dec(key)) + return; + + schedule_delayed_work(work, timeout); } -EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred); +EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred); -void static_key_deferred_flush(struct static_key_deferred *key) +void __static_key_deferred_flush(void *key, struct delayed_work *work) { STATIC_KEY_CHECK_USE(key); - flush_delayed_work(&key->work); + flush_delayed_work(work); } -EXPORT_SYMBOL_GPL(static_key_deferred_flush); +EXPORT_SYMBOL_GPL(__static_key_deferred_flush); void jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl) @@ -374,25 +398,55 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry) return enabled ^ branch; } +static bool jump_label_can_update(struct jump_entry *entry, bool init) +{ + /* + * Cannot update code that was in an init text area. + */ + if (!init && jump_entry_is_init(entry)) + return false; + + if (!kernel_text_address(jump_entry_code(entry))) { + WARN_ONCE(1, "can't patch jump_label at %pS", (void *)jump_entry_code(entry)); + return false; + } + + return true; +} + +#ifndef HAVE_JUMP_LABEL_BATCH static void __jump_label_update(struct static_key *key, struct jump_entry *entry, struct jump_entry *stop, bool init) { for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { - /* - * An entry->code of 0 indicates an entry which has been - * disabled because it was in an init text area. - */ - if (init || !jump_entry_is_init(entry)) { - if (kernel_text_address(jump_entry_code(entry))) - arch_jump_label_transform(entry, jump_label_type(entry)); - else - WARN_ONCE(1, "can't patch jump_label at %pS", - (void *)jump_entry_code(entry)); + if (jump_label_can_update(entry, init)) + arch_jump_label_transform(entry, jump_label_type(entry)); + } +} +#else +static void __jump_label_update(struct static_key *key, + struct jump_entry *entry, + struct jump_entry *stop, + bool init) +{ + for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { + + if (!jump_label_can_update(entry, init)) + continue; + + if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) { + /* + * Queue is full: Apply the current queue and try again. + */ + arch_jump_label_transform_apply(); + BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry))); } } + arch_jump_label_transform_apply(); } +#endif void __init jump_label_init(void) { |