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kernel/jump_label.c
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// SPDX-License-Identifier: GPL-2.0-only |
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/* * jump label support * * Copyright (C) 2009 Jason Baron <jbaron@redhat.com> |
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* Copyright (C) 2011 Peter Zijlstra |
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* */ |
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#include <linux/memory.h> #include <linux/uaccess.h> #include <linux/module.h> #include <linux/list.h> |
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#include <linux/slab.h> #include <linux/sort.h> #include <linux/err.h> |
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#include <linux/static_key.h> |
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#include <linux/jump_label_ratelimit.h> |
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#include <linux/bug.h> |
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#include <linux/cpu.h> |
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#include <asm/sections.h> |
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|
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/* mutex to protect coming/going of the jump_label table */ |
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static DEFINE_MUTEX(jump_label_mutex); |
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void jump_label_lock(void) { mutex_lock(&jump_label_mutex); } void jump_label_unlock(void) { mutex_unlock(&jump_label_mutex); } |
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static int jump_label_cmp(const void *a, const void *b) { const struct jump_entry *jea = a; const struct jump_entry *jeb = b; |
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/* * Entrires are sorted by key. */ |
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if (jump_entry_key(jea) < jump_entry_key(jeb)) |
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return -1; |
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if (jump_entry_key(jea) > jump_entry_key(jeb)) |
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return 1; |
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/* * 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; |
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return 0; } |
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static void jump_label_swap(void *a, void *b, int size) { long delta = (unsigned long)a - (unsigned long)b; struct jump_entry *jea = a; struct jump_entry *jeb = b; struct jump_entry tmp = *jea; jea->code = jeb->code - delta; jea->target = jeb->target - delta; jea->key = jeb->key - delta; jeb->code = tmp.code + delta; jeb->target = tmp.target + delta; jeb->key = tmp.key + delta; } |
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static void |
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jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) |
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{ unsigned long size; |
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void *swapfn = NULL; if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE)) swapfn = jump_label_swap; |
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size = (((unsigned long)stop - (unsigned long)start) / sizeof(struct jump_entry)); |
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sort(start, size, sizeof(struct jump_entry), jump_label_cmp, swapfn); |
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} |
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static void jump_label_update(struct static_key *key); |
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/* |
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* There are similar definitions for the !CONFIG_JUMP_LABEL case in jump_label.h. |
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* 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 |
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* used in the branch statements as it is for the !CONFIG_JUMP_LABEL case its ok |
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* 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 |
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* to be included from most/all places for CONFIG_JUMP_LABEL. |
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*/ 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); |
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void static_key_slow_inc_cpuslocked(struct static_key *key) |
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{ |
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int v, v1; |
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STATIC_KEY_CHECK_USE(key); |
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lockdep_assert_cpus_held(); |
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/* * 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); |
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if (likely(v1 == v)) |
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return; } |
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|
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jump_label_lock(); |
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if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); |
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jump_label_update(key); |
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/* * 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); |
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} else { atomic_inc(&key->enabled); } |
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jump_label_unlock(); |
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} void static_key_slow_inc(struct static_key *key) { cpus_read_lock(); static_key_slow_inc_cpuslocked(key); |
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cpus_read_unlock(); |
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} |
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EXPORT_SYMBOL_GPL(static_key_slow_inc); |
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|
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void static_key_enable_cpuslocked(struct static_key *key) |
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{ |
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STATIC_KEY_CHECK_USE(key); |
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lockdep_assert_cpus_held(); |
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|
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if (atomic_read(&key->enabled) > 0) { WARN_ON_ONCE(atomic_read(&key->enabled) != 1); return; } |
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jump_label_lock(); if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); jump_label_update(key); |
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/* * See static_key_slow_inc(). */ atomic_set_release(&key->enabled, 1); |
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} jump_label_unlock(); |
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} EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked); void static_key_enable(struct static_key *key) { cpus_read_lock(); static_key_enable_cpuslocked(key); |
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cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_enable); |
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void static_key_disable_cpuslocked(struct static_key *key) |
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{ |
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STATIC_KEY_CHECK_USE(key); |
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lockdep_assert_cpus_held(); |
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if (atomic_read(&key->enabled) != 1) { WARN_ON_ONCE(atomic_read(&key->enabled) != 0); return; } |
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jump_label_lock(); if (atomic_cmpxchg(&key->enabled, 1, 0)) jump_label_update(key); jump_label_unlock(); |
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} EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked); void static_key_disable(struct static_key *key) { cpus_read_lock(); static_key_disable_cpuslocked(key); |
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cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_disable); |
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static bool static_key_slow_try_dec(struct static_key *key) |
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{ |
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int val; |
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val = atomic_fetch_add_unless(&key->enabled, -1, 1); if (val == 1) return false; |
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/* * 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. */ |
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WARN(val < 0, "jump label: negative count! "); return true; } |
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static void __static_key_slow_dec_cpuslocked(struct static_key *key) |
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{ lockdep_assert_cpus_held(); if (static_key_slow_try_dec(key)) |
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return; |
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|
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jump_label_lock(); |
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if (atomic_dec_and_test(&key->enabled)) jump_label_update(key); |
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jump_label_unlock(); |
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} |
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static void __static_key_slow_dec(struct static_key *key) |
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{ cpus_read_lock(); |
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__static_key_slow_dec_cpuslocked(key); |
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cpus_read_unlock(); |
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} |
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void jump_label_update_timeout(struct work_struct *work) |
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{ |
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struct static_key_deferred *key = container_of(work, struct static_key_deferred, work.work); |
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__static_key_slow_dec(&key->key); |
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} |
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EXPORT_SYMBOL_GPL(jump_label_update_timeout); |
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|
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void static_key_slow_dec(struct static_key *key) |
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{ |
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STATIC_KEY_CHECK_USE(key); |
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__static_key_slow_dec(key); |
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} |
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EXPORT_SYMBOL_GPL(static_key_slow_dec); |
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|
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void static_key_slow_dec_cpuslocked(struct static_key *key) { STATIC_KEY_CHECK_USE(key); |
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__static_key_slow_dec_cpuslocked(key); |
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} |
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void __static_key_slow_dec_deferred(struct static_key *key, struct delayed_work *work, unsigned long timeout) |
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{ |
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STATIC_KEY_CHECK_USE(key); |
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if (static_key_slow_try_dec(key)) return; schedule_delayed_work(work, timeout); |
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} |
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EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred); |
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void __static_key_deferred_flush(void *key, struct delayed_work *work) |
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{ |
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STATIC_KEY_CHECK_USE(key); |
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flush_delayed_work(work); |
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} |
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EXPORT_SYMBOL_GPL(__static_key_deferred_flush); |
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|
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void jump_label_rate_limit(struct static_key_deferred *key, |
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unsigned long rl) { |
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STATIC_KEY_CHECK_USE(key); |
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key->timeout = rl; INIT_DELAYED_WORK(&key->work, jump_label_update_timeout); } |
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EXPORT_SYMBOL_GPL(jump_label_rate_limit); |
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static int addr_conflict(struct jump_entry *entry, void *start, void *end) { |
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if (jump_entry_code(entry) <= (unsigned long)end && jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE > (unsigned long)start) |
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return 1; return 0; } |
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static int __jump_label_text_reserved(struct jump_entry *iter_start, struct jump_entry *iter_stop, void *start, void *end) |
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{ |
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struct jump_entry *iter; |
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|
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iter = iter_start; while (iter < iter_stop) { |
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if (addr_conflict(iter, start, end)) return 1; |
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iter++; } |
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return 0; } |
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/* |
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* 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. */ |
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void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry, |
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enum jump_label_type type) { |
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arch_jump_label_transform(entry, type); |
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} |
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static inline struct jump_entry *static_key_entries(struct static_key *key) |
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{ |
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WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED); return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK); |
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} |
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static inline bool static_key_type(struct static_key *key) |
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{ |
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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; |
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} |
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|
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/*** * 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; } |
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static enum jump_label_type jump_label_type(struct jump_entry *entry) |
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{ |
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struct static_key *key = jump_entry_key(entry); |
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bool enabled = static_key_enabled(key); |
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bool branch = jump_entry_is_branch(entry); |
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|
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/* See the comment in linux/jump_label.h */ return enabled ^ branch; |
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} |
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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))) { |
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WARN_ONCE(!jump_entry_is_init(entry), "can't patch jump_label at %pS", (void *)jump_entry_code(entry)); |
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return false; } return true; } |
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#ifndef HAVE_JUMP_LABEL_BATCH |
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static void __jump_label_update(struct static_key *key, struct jump_entry *entry, |
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struct jump_entry *stop, bool init) |
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{ for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { |
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if (jump_label_can_update(entry, init)) arch_jump_label_transform(entry, jump_label_type(entry)); |
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} } |
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#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 |
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|
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void __init jump_label_init(void) |
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{ |
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struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; |
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struct static_key *key = NULL; |
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struct jump_entry *iter; |
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/* * 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); |
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if (static_key_initialized) return; |
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cpus_read_lock(); |
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jump_label_lock(); |
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jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { |
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struct static_key *iterk; |
37348804e jump_label: if a ... |
448 |
|
11276d530 locking/static_ke... |
449 450 451 |
/* rewrite NOPs */ if (jump_label_type(iter) == JUMP_LABEL_NOP) arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); |
194836776 jump_label: Annot... |
452 453 |
if (init_section_contains((void *)jump_entry_code(iter), 1)) jump_entry_set_init(iter); |
7dcfd915b jump_label: Add j... |
454 |
iterk = jump_entry_key(iter); |
37348804e jump_label: if a ... |
455 |
if (iterk == key) |
d430d3d7e jump label: Intro... |
456 |
continue; |
37348804e jump_label: if a ... |
457 |
key = iterk; |
3821fd35b jump_label: Reduc... |
458 |
static_key_set_entries(key, iter); |
bf5438fca jump label: Base ... |
459 |
} |
c4b2c0c5f static_key: WARN ... |
460 |
static_key_initialized = true; |
91bad2f8d jump label: Fix d... |
461 |
jump_label_unlock(); |
f2545b2d4 jump_label: Reord... |
462 |
cpus_read_unlock(); |
bf5438fca jump label: Base ... |
463 |
} |
bf5438fca jump label: Base ... |
464 465 |
#ifdef CONFIG_MODULES |
11276d530 locking/static_ke... |
466 467 468 469 |
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); |
9ae033aca jump_label: Abstr... |
470 |
bool branch = jump_entry_is_branch(entry); |
11276d530 locking/static_ke... |
471 472 473 474 |
/* See the comment in linux/jump_label.h */ return type ^ branch; } |
c5905afb0 static keys: Intr... |
475 476 |
struct static_key_mod { struct static_key_mod *next; |
d430d3d7e jump label: Intro... |
477 478 479 |
struct jump_entry *entries; struct module *mod; }; |
3821fd35b jump_label: Reduc... |
480 481 |
static inline struct static_key_mod *static_key_mod(struct static_key *key) { |
34e12b864 jump_label: Use s... |
482 |
WARN_ON_ONCE(!static_key_linked(key)); |
3821fd35b jump_label: Reduc... |
483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 |
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... |
502 503 504 |
static int __jump_label_mod_text_reserved(void *start, void *end) { struct module *mod; |
0db6e3734 jump_label,module... |
505 |
int ret; |
d430d3d7e jump label: Intro... |
506 |
|
bdc9f3735 jump_label: disab... |
507 |
preempt_disable(); |
d430d3d7e jump label: Intro... |
508 |
mod = __module_text_address((unsigned long)start); |
bdc9f3735 jump_label: disab... |
509 |
WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod); |
0db6e3734 jump_label,module... |
510 511 |
if (!try_module_get(mod)) mod = NULL; |
bdc9f3735 jump_label: disab... |
512 |
preempt_enable(); |
d430d3d7e jump label: Intro... |
513 514 |
if (!mod) return 0; |
0db6e3734 jump_label,module... |
515 |
ret = __jump_label_text_reserved(mod->jump_entries, |
d430d3d7e jump label: Intro... |
516 517 |
mod->jump_entries + mod->num_jump_entries, start, end); |
0db6e3734 jump_label,module... |
518 519 520 521 |
module_put(mod); return ret; |
d430d3d7e jump label: Intro... |
522 |
} |
706249c22 locking/static_ke... |
523 |
static void __jump_label_mod_update(struct static_key *key) |
d430d3d7e jump label: Intro... |
524 |
{ |
706249c22 locking/static_ke... |
525 |
struct static_key_mod *mod; |
d430d3d7e jump label: Intro... |
526 |
|
3821fd35b jump_label: Reduc... |
527 528 529 530 531 532 533 534 535 536 |
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... |
537 |
|
3821fd35b jump_label: Reduc... |
538 539 540 541 542 |
m = mod->mod; if (!m) stop = __stop___jump_table; else stop = m->jump_entries + m->num_jump_entries; |
194836776 jump_label: Annot... |
543 |
__jump_label_update(key, mod->entries, stop, |
77ac1c02d jump_label: Fix N... |
544 |
m && m->state == MODULE_STATE_COMING); |
d430d3d7e jump label: Intro... |
545 546 547 548 549 550 551 552 553 554 555 556 |
} } /*** * 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 ... |
557 |
{ |
d430d3d7e jump label: Intro... |
558 559 560 561 562 563 564 |
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... |
565 566 567 568 569 |
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 ... |
570 |
} |
d430d3d7e jump label: Intro... |
571 |
static int jump_label_add_module(struct module *mod) |
bf5438fca jump label: Base ... |
572 |
{ |
d430d3d7e jump label: Intro... |
573 574 575 |
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... |
576 |
struct static_key *key = NULL; |
3821fd35b jump_label: Reduc... |
577 |
struct static_key_mod *jlm, *jlm2; |
bf5438fca jump label: Base ... |
578 579 |
/* if the module doesn't have jump label entries, just return */ |
d430d3d7e jump label: Intro... |
580 |
if (iter_start == iter_stop) |
bf5438fca jump label: Base ... |
581 |
return 0; |
d430d3d7e jump label: Intro... |
582 583 584 |
jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { |
c5905afb0 static keys: Intr... |
585 |
struct static_key *iterk; |
d430d3d7e jump label: Intro... |
586 |
|
194836776 jump_label: Annot... |
587 588 |
if (within_module_init(jump_entry_code(iter), mod)) jump_entry_set_init(iter); |
7dcfd915b jump_label: Add j... |
589 |
iterk = jump_entry_key(iter); |
c5905afb0 static keys: Intr... |
590 591 |
if (iterk == key) continue; |
d430d3d7e jump label: Intro... |
592 |
|
c5905afb0 static keys: Intr... |
593 |
key = iterk; |
9ae033aca jump_label: Abstr... |
594 |
if (within_module((unsigned long)key, mod)) { |
3821fd35b jump_label: Reduc... |
595 |
static_key_set_entries(key, iter); |
d430d3d7e jump label: Intro... |
596 |
continue; |
bf5438fca jump label: Base ... |
597 |
} |
c5905afb0 static keys: Intr... |
598 |
jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL); |
d430d3d7e jump label: Intro... |
599 600 |
if (!jlm) return -ENOMEM; |
3821fd35b jump_label: Reduc... |
601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 |
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... |
616 617 |
jlm->mod = mod; jlm->entries = iter; |
3821fd35b jump_label: Reduc... |
618 619 620 |
jlm->next = static_key_mod(key); static_key_set_mod(key, jlm); static_key_set_linked(key); |
d430d3d7e jump label: Intro... |
621 |
|
11276d530 locking/static_ke... |
622 623 |
/* Only update if we've changed from our initial state */ if (jump_label_type(iter) != jump_label_init_type(iter)) |
194836776 jump_label: Annot... |
624 |
__jump_label_update(key, iter, iter_stop, true); |
bf5438fca jump label: Base ... |
625 |
} |
d430d3d7e jump label: Intro... |
626 |
|
bf5438fca jump label: Base ... |
627 628 |
return 0; } |
d430d3d7e jump label: Intro... |
629 |
static void jump_label_del_module(struct module *mod) |
bf5438fca jump label: Base ... |
630 |
{ |
d430d3d7e jump label: Intro... |
631 632 633 |
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... |
634 635 |
struct static_key *key = NULL; struct static_key_mod *jlm, **prev; |
bf5438fca jump label: Base ... |
636 |
|
d430d3d7e jump label: Intro... |
637 |
for (iter = iter_start; iter < iter_stop; iter++) { |
7dcfd915b jump_label: Add j... |
638 |
if (jump_entry_key(iter) == key) |
d430d3d7e jump label: Intro... |
639 |
continue; |
7dcfd915b jump_label: Add j... |
640 |
key = jump_entry_key(iter); |
d430d3d7e jump label: Intro... |
641 |
|
9ae033aca jump_label: Abstr... |
642 |
if (within_module((unsigned long)key, mod)) |
d430d3d7e jump label: Intro... |
643 |
continue; |
3821fd35b jump_label: Reduc... |
644 645 646 |
/* No memory during module load */ if (WARN_ON(!static_key_linked(key))) continue; |
d430d3d7e jump label: Intro... |
647 |
prev = &key->next; |
3821fd35b jump_label: Reduc... |
648 |
jlm = static_key_mod(key); |
bf5438fca jump label: Base ... |
649 |
|
d430d3d7e jump label: Intro... |
650 651 652 653 |
while (jlm && jlm->mod != mod) { prev = &jlm->next; jlm = jlm->next; } |
3821fd35b jump_label: Reduc... |
654 655 656 657 658 659 660 |
/* 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... |
661 |
*prev = jlm->next; |
3821fd35b jump_label: Reduc... |
662 663 664 665 666 667 668 669 |
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... |
670 |
kfree(jlm); |
bf5438fca jump label: Base ... |
671 672 673 674 675 676 677 678 679 680 |
} } } 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... |
681 682 |
cpus_read_lock(); jump_label_lock(); |
bf5438fca jump label: Base ... |
683 684 |
switch (val) { case MODULE_STATE_COMING: |
d430d3d7e jump label: Intro... |
685 |
ret = jump_label_add_module(mod); |
3821fd35b jump_label: Reduc... |
686 |
if (ret) { |
da260fe12 jump_label: Fix t... |
687 688 |
WARN(1, "Failed to allocate memory: jump_label may not work properly. "); |
d430d3d7e jump label: Intro... |
689 |
jump_label_del_module(mod); |
3821fd35b jump_label: Reduc... |
690 |
} |
bf5438fca jump label: Base ... |
691 692 |
break; case MODULE_STATE_GOING: |
d430d3d7e jump label: Intro... |
693 |
jump_label_del_module(mod); |
bf5438fca jump label: Base ... |
694 695 |
break; } |
bf5438fca jump label: Base ... |
696 |
|
f2545b2d4 jump_label: Reord... |
697 698 |
jump_label_unlock(); cpus_read_unlock(); |
d430d3d7e jump label: Intro... |
699 |
return notifier_from_errno(ret); |
bf5438fca jump label: Base ... |
700 |
} |
885885f6b locking/static_ke... |
701 |
static struct notifier_block jump_label_module_nb = { |
bf5438fca jump label: Base ... |
702 |
.notifier_call = jump_label_module_notify, |
d430d3d7e jump label: Intro... |
703 |
.priority = 1, /* higher than tracepoints */ |
bf5438fca jump label: Base ... |
704 |
}; |
d430d3d7e jump label: Intro... |
705 |
static __init int jump_label_init_module(void) |
bf5438fca jump label: Base ... |
706 707 708 |
{ return register_module_notifier(&jump_label_module_nb); } |
d430d3d7e jump label: Intro... |
709 |
early_initcall(jump_label_init_module); |
bf5438fca jump label: Base ... |
710 711 |
#endif /* CONFIG_MODULES */ |
d430d3d7e jump label: Intro... |
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 |
/*** * 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... |
738 |
static void jump_label_update(struct static_key *key) |
d430d3d7e jump label: Intro... |
739 |
{ |
c5905afb0 static keys: Intr... |
740 |
struct jump_entry *stop = __stop___jump_table; |
3821fd35b jump_label: Reduc... |
741 |
struct jump_entry *entry; |
d430d3d7e jump label: Intro... |
742 |
#ifdef CONFIG_MODULES |
bed831f9a module, jump_labe... |
743 |
struct module *mod; |
140fe3b1a jump_label: Fix j... |
744 |
|
3821fd35b jump_label: Reduc... |
745 746 747 748 |
if (static_key_linked(key)) { __jump_label_mod_update(key); return; } |
140fe3b1a jump_label: Fix j... |
749 |
|
bed831f9a module, jump_labe... |
750 751 |
preempt_disable(); mod = __module_address((unsigned long)key); |
140fe3b1a jump_label: Fix j... |
752 753 |
if (mod) stop = mod->jump_entries + mod->num_jump_entries; |
bed831f9a module, jump_labe... |
754 |
preempt_enable(); |
d430d3d7e jump label: Intro... |
755 |
#endif |
3821fd35b jump_label: Reduc... |
756 |
entry = static_key_entries(key); |
140fe3b1a jump_label: Fix j... |
757 758 |
/* if there are no users, entry can be NULL */ if (entry) |
194836776 jump_label: Annot... |
759 760 |
__jump_label_update(key, entry, stop, system_state < SYSTEM_RUNNING); |
d430d3d7e jump label: Intro... |
761 |
} |
1987c947d locking/static_ke... |
762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 |
#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... |
796 |
early_initcall(jump_label_test); |
1987c947d locking/static_ke... |
797 |
#endif /* STATIC_KEYS_SELFTEST */ |