/* * jump label support * * Copyright (C) 2009 Jason Baron <jbaron@redhat.com> * Copyright (C) 2011 Peter Zijlstra * */#include <linux/memory.h>#include <linux/uaccess.h>#include <linux/module.h>#include <linux/list.h>#include <linux/slab.h>#include <linux/sort.h>#include <linux/err.h>#include <linux/static_key.h>#include <linux/jump_label_ratelimit.h>#include <linux/bug.h>#include <linux/cpu.h> #ifdef HAVE_JUMP_LABEL /* mutex to protect coming/going of the the jump_label table */static DEFINE_MUTEX(jump_label_mutex); void jump_label_lock(void){ mutex_lock(&jump_label_mutex);} void jump_label_unlock(void){ mutex_unlock(&jump_label_mutex);} 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 voidjump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop){ 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);} static void jump_label_update(struct static_key *key); /* * 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); void static_key_enable(struct static_key *key){ int count = static_key_count(key); WARN_ON_ONCE(count < 0 || count > 1); if (!count) static_key_slow_inc(key);}EXPORT_SYMBOL_GPL(static_key_enable); void static_key_disable(struct static_key *key){ int count = static_key_count(key); WARN_ON_ONCE(count < 0 || count > 1); if (count) static_key_slow_dec(key);}EXPORT_SYMBOL_GPL(static_key_disable); void static_key_slow_inc(struct static_key *key){ int v, v1; STATIC_KEY_CHECK_USE(); /* * 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); if (likely(v1 == v)) return; } cpus_read_lock(); jump_label_lock(); if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); jump_label_update(key); atomic_set(&key->enabled, 1); } else { atomic_inc(&key->enabled); } jump_label_unlock(); cpus_read_unlock();}EXPORT_SYMBOL_GPL(static_key_slow_inc); static void __static_key_slow_dec(struct static_key *key, unsigned long rate_limit, struct delayed_work *work){ cpus_read_lock(); /* * 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. */ if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { WARN(atomic_read(&key->enabled) < 0, "jump label: negative count!\n"); cpus_read_unlock(); return; } if (rate_limit) { atomic_inc(&key->enabled); schedule_delayed_work(work, rate_limit); } else { jump_label_update(key); } jump_label_unlock(); cpus_read_unlock();} static 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);} void static_key_slow_dec(struct static_key *key){ STATIC_KEY_CHECK_USE(); __static_key_slow_dec(key, 0, NULL);}EXPORT_SYMBOL_GPL(static_key_slow_dec); void static_key_slow_dec_deferred(struct static_key_deferred *key){ STATIC_KEY_CHECK_USE(); __static_key_slow_dec(&key->key, key->timeout, &key->work);}EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred); void static_key_deferred_flush(struct static_key_deferred *key){ STATIC_KEY_CHECK_USE(); flush_delayed_work(&key->work);}EXPORT_SYMBOL_GPL(static_key_deferred_flush); void jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl){ STATIC_KEY_CHECK_USE(); key->timeout = rl; INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);}EXPORT_SYMBOL_GPL(jump_label_rate_limit); 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;} static int __jump_label_text_reserved(struct jump_entry *iter_start, struct jump_entry *iter_stop, void *start, void *end){ struct jump_entry *iter; iter = iter_start; while (iter < iter_stop) { if (addr_conflict(iter, start, end)) return 1; iter++; } return 0;} /* * 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. */void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type){ arch_jump_label_transform(entry, type);} static inline struct jump_entry *static_key_entries(struct static_key *key){ WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED); return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);} static inline bool static_key_type(struct static_key *key){ 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;} static inline struct static_key *jump_entry_key(struct jump_entry *entry){ return (struct static_key *)((unsigned long)entry->key & ~1UL);} static bool jump_entry_branch(struct jump_entry *entry){ return (unsigned long)entry->key & 1UL;} /*** * 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;} static enum jump_label_type jump_label_type(struct jump_entry *entry){ struct static_key *key = jump_entry_key(entry); bool enabled = static_key_enabled(key); bool branch = jump_entry_branch(entry); /* See the comment in linux/jump_label.h */ return enabled ^ branch;} 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++) { /* * entry->code set to 0 invalidates module init text sections * kernel_text_address() verifies we are not in core kernel * init code, see jump_label_invalidate_module_init(). */ if (entry->code && kernel_text_address(entry->code)) arch_jump_label_transform(entry, jump_label_type(entry)); }} void __init jump_label_init(void){ struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; struct static_key *key = NULL; struct jump_entry *iter; /* * 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); if (static_key_initialized) return; cpus_read_lock(); jump_label_lock(); jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { struct static_key *iterk; /* rewrite NOPs */ if (jump_label_type(iter) == JUMP_LABEL_NOP) arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); iterk = jump_entry_key(iter); if (iterk == key) continue; key = iterk; static_key_set_entries(key, iter); } static_key_initialized = true; jump_label_unlock(); cpus_read_unlock();} #ifdef CONFIG_MODULES 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;} struct static_key_mod { struct static_key_mod *next; struct jump_entry *entries; struct module *mod;}; 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;} static int __jump_label_mod_text_reserved(void *start, void *end){ struct module *mod; preempt_disable(); mod = __module_text_address((unsigned long)start); WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod); preempt_enable(); if (!mod) return 0; return __jump_label_text_reserved(mod->jump_entries, mod->jump_entries + mod->num_jump_entries, start, end);} static void __jump_label_mod_update(struct static_key *key){ struct static_key_mod *mod; 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; 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); }} /*** * 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){ 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; 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); }} static int jump_label_add_module(struct module *mod){ struct jump_entry *iter_start = mod->jump_entries; struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; struct jump_entry *iter; struct static_key *key = NULL; struct static_key_mod *jlm, *jlm2; /* if the module doesn't have jump label entries, just return */ if (iter_start == iter_stop) return 0; jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { struct static_key *iterk; iterk = jump_entry_key(iter); if (iterk == key) continue; key = iterk; if (within_module(iter->key, mod)) { static_key_set_entries(key, iter); continue; } jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);Lines 1–500 of 727. 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/* * jump label support * * Copyright (C) 2009 Jason Baron <jbaron@redhat.com> * Copyright (C) 2011 Peter Zijlstra * */ #include <linux/memory.h> #include <linux/uaccess.h> #include <linux/module.h> #include <linux/list.h> #include <linux/slab.h> #include <linux/sort.h> #include <linux/err.h> #include <linux/static_key.h> #include <linux/jump_label_ratelimit.h> #include <linux/bug.h> #include <linux/cpu.h> #ifdef HAVE_JUMP_LABEL /* mutex to protect coming/going of the the jump_label table */ static DEFINE_MUTEX(jump_label_mutex); void jump_label_lock(void) { mutex_lock(&jump_label_mutex); } void jump_label_unlock(void) { mutex_unlock(&jump_label_mutex); } 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 jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) { 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); } static void jump_label_update(struct static_key *key); /* * 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); void static_key_enable(struct static_key *key) { int count = static_key_count(key); WARN_ON_ONCE(count < 0 || count > 1); if (!count) static_key_slow_inc(key); } EXPORT_SYMBOL_GPL(static_key_enable); void static_key_disable(struct static_key *key) { int count = static_key_count(key); WARN_ON_ONCE(count < 0 || count > 1); if (count) static_key_slow_dec(key); } EXPORT_SYMBOL_GPL(static_key_disable); void static_key_slow_inc(struct static_key *key) { int v, v1; STATIC_KEY_CHECK_USE(); /* * 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); if (likely(v1 == v)) return; } cpus_read_lock(); jump_label_lock(); if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); jump_label_update(key); atomic_set(&key->enabled, 1); } else { atomic_inc(&key->enabled); } jump_label_unlock(); cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_slow_inc); static void __static_key_slow_dec(struct static_key *key, unsigned long rate_limit, struct delayed_work *work) { cpus_read_lock(); /* * 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. */ if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { WARN(atomic_read(&key->enabled) < 0, "jump label: negative count!\n"); cpus_read_unlock(); return; } if (rate_limit) { atomic_inc(&key->enabled); schedule_delayed_work(work, rate_limit); } else { jump_label_update(key); } jump_label_unlock(); cpus_read_unlock(); } static 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); } void static_key_slow_dec(struct static_key *key) { STATIC_KEY_CHECK_USE(); __static_key_slow_dec(key, 0, NULL); } EXPORT_SYMBOL_GPL(static_key_slow_dec); void static_key_slow_dec_deferred(struct static_key_deferred *key) { STATIC_KEY_CHECK_USE(); __static_key_slow_dec(&key->key, key->timeout, &key->work); } EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred); void static_key_deferred_flush(struct static_key_deferred *key) { STATIC_KEY_CHECK_USE(); flush_delayed_work(&key->work); } EXPORT_SYMBOL_GPL(static_key_deferred_flush); void jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl) { STATIC_KEY_CHECK_USE(); key->timeout = rl; INIT_DELAYED_WORK(&key->work, jump_label_update_timeout); } EXPORT_SYMBOL_GPL(jump_label_rate_limit); 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; } static int __jump_label_text_reserved(struct jump_entry *iter_start, struct jump_entry *iter_stop, void *start, void *end) { struct jump_entry *iter; iter = iter_start; while (iter < iter_stop) { if (addr_conflict(iter, start, end)) return 1; iter++; } return 0; } /* * 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. */ void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type) { arch_jump_label_transform(entry, type); } static inline struct jump_entry *static_key_entries(struct static_key *key) { WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED); return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK); } static inline bool static_key_type(struct static_key *key) { 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; } static inline struct static_key *jump_entry_key(struct jump_entry *entry) { return (struct static_key *)((unsigned long)entry->key & ~1UL); } static bool jump_entry_branch(struct jump_entry *entry) { return (unsigned long)entry->key & 1UL; } /*** * 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; } static enum jump_label_type jump_label_type(struct jump_entry *entry) { struct static_key *key = jump_entry_key(entry); bool enabled = static_key_enabled(key); bool branch = jump_entry_branch(entry); /* See the comment in linux/jump_label.h */ return enabled ^ branch; } 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++) { /* * entry->code set to 0 invalidates module init text sections * kernel_text_address() verifies we are not in core kernel * init code, see jump_label_invalidate_module_init(). */ if (entry->code && kernel_text_address(entry->code)) arch_jump_label_transform(entry, jump_label_type(entry)); } } void __init jump_label_init(void) { struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; struct static_key *key = NULL; struct jump_entry *iter; /* * 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); if (static_key_initialized) return; cpus_read_lock(); jump_label_lock(); jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { struct static_key *iterk; /* rewrite NOPs */ if (jump_label_type(iter) == JUMP_LABEL_NOP) arch_jump_label_transform_static(iter, JUMP_LABEL_NOP); iterk = jump_entry_key(iter); if (iterk == key) continue; key = iterk; static_key_set_entries(key, iter); } static_key_initialized = true; jump_label_unlock(); cpus_read_unlock(); } #ifdef CONFIG_MODULES 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; } struct static_key_mod { struct static_key_mod *next; struct jump_entry *entries; struct module *mod; }; 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; } static int __jump_label_mod_text_reserved(void *start, void *end) { struct module *mod; preempt_disable(); mod = __module_text_address((unsigned long)start); WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod); preempt_enable(); if (!mod) return 0; return __jump_label_text_reserved(mod->jump_entries, mod->jump_entries + mod->num_jump_entries, start, end); } static void __jump_label_mod_update(struct static_key *key) { struct static_key_mod *mod; 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; 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); } } /*** * 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) { 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; 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); } } static int jump_label_add_module(struct module *mod) { struct jump_entry *iter_start = mod->jump_entries; struct jump_entry *iter_stop = iter_start + mod->num_jump_entries; struct jump_entry *iter; struct static_key *key = NULL; struct static_key_mod *jlm, *jlm2; /* if the module doesn't have jump label entries, just return */ if (iter_start == iter_stop) return 0; jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { struct static_key *iterk; iterk = jump_entry_key(iter); if (iterk == key) continue; key = iterk; if (within_module(iter->key, mod)) { static_key_set_entries(key, iter); continue; } jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);