static inline struct jump_entry *static_key_entries(struct static_key *key)
{
- return (struct jump_entry *)((unsigned long)key->entries & ~JUMP_TYPE_MASK);
+ 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 (unsigned long)key->entries & JUMP_TYPE_MASK;
+ 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 (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);
continue;
key = iterk;
- /*
- * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
- */
- *((unsigned long *)&key->entries) += (unsigned long)iter;
-#ifdef CONFIG_MODULES
- key->next = NULL;
-#endif
+ static_key_set_entries(key, iter);
}
static_key_initialized = true;
jump_label_unlock();
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;
{
struct static_key_mod *mod;
- for (mod = key->next; mod; mod = mod->next) {
- struct module *m = 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;
- __jump_label_update(key, mod->entries,
- m->jump_entries + m->num_jump_entries);
+ 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);
}
}
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;
+ struct static_key_mod *jlm, *jlm2;
/* if the module doesn't have jump label entries, just return */
if (iter_start == iter_stop)
key = iterk;
if (within_module(iter->key, mod)) {
- /*
- * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
- */
- *((unsigned long *)&key->entries) += (unsigned long)iter;
- key->next = NULL;
+ static_key_set_entries(key, iter);
continue;
}
jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
if (!jlm)
return -ENOMEM;
+ 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);
+ }
jlm->mod = mod;
jlm->entries = iter;
- jlm->next = key->next;
- key->next = jlm;
+ jlm->next = static_key_mod(key);
+ static_key_set_mod(key, jlm);
+ static_key_set_linked(key);
/* Only update if we've changed from our initial state */
if (jump_label_type(iter) != jump_label_init_type(iter))
if (within_module(iter->key, mod))
continue;
+ /* No memory during module load */
+ if (WARN_ON(!static_key_linked(key)))
+ continue;
+
prev = &key->next;
- jlm = key->next;
+ jlm = static_key_mod(key);
while (jlm && jlm->mod != mod) {
prev = &jlm->next;
jlm = jlm->next;
}
- if (jlm) {
+ /* No memory during module load */
+ if (WARN_ON(!jlm))
+ continue;
+
+ if (prev == &key->next)
+ static_key_set_mod(key, jlm->next);
+ else
*prev = jlm->next;
+
+ 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);
kfree(jlm);
}
}
case MODULE_STATE_COMING:
jump_label_lock();
ret = jump_label_add_module(mod);
- if (ret)
+ if (ret) {
+ WARN(1, "Failed to allocatote memory: jump_label may not work properly.\n");
jump_label_del_module(mod);
+ }
jump_label_unlock();
break;
case MODULE_STATE_GOING:
static void jump_label_update(struct static_key *key)
{
struct jump_entry *stop = __stop___jump_table;
- struct jump_entry *entry = static_key_entries(key);
+ struct jump_entry *entry;
#ifdef CONFIG_MODULES
struct module *mod;
- __jump_label_mod_update(key);
+ if (static_key_linked(key)) {
+ __jump_label_mod_update(key);
+ return;
+ }
preempt_disable();
mod = __module_address((unsigned long)key);
stop = mod->jump_entries + mod->num_jump_entries;
preempt_enable();
#endif
+ entry = static_key_entries(key);
/* if there are no users, entry can be NULL */
if (entry)
__jump_label_update(key, entry, stop);
git.samba.org / sfrench / cifs-2.6.git / blobdiff