[linux.git] / kernel / jump_label.c

/*
 * jump label support
 *
 * Copyright (C) 2009 Jason Baron <[email protected]>
 * Copyright (C) 2011 Peter Zijlstra <[email protected]>
 *
 */
#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>

#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, int enable);

void static_key_slow_inc(struct static_key *key)
{
	if (atomic_inc_not_zero(&key->enabled))
		return;

	jump_label_lock();
	if (atomic_read(&key->enabled) == 0) {
		if (!jump_label_get_branch_default(key))
			jump_label_update(key, JUMP_LABEL_ENABLE);
		else
			jump_label_update(key, JUMP_LABEL_DISABLE);
	}
	atomic_inc(&key->enabled);
	jump_label_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)
{
	if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
		WARN(atomic_read(&key->enabled) < 0,
		     "jump label: negative count!\n");
		return;
	}

	if (rate_limit) {
		atomic_inc(&key->enabled);
		schedule_delayed_work(work, rate_limit);
	} else {
		if (!jump_label_get_branch_default(key))
			jump_label_update(key, JUMP_LABEL_DISABLE);
		else
			jump_label_update(key, JUMP_LABEL_ENABLE);
	}
	jump_label_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_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_slow_dec(&key->key, key->timeout, &key->work);
}
EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);

void jump_label_rate_limit(struct static_key_deferred *key,
		unsigned long rl)
{
	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 void __jump_label_update(struct static_key *key,
				struct jump_entry *entry,
				struct jump_entry *stop, int enable)
{
	for (; (entry < stop) &&
	      (entry->key == (jump_label_t)(unsigned long)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, enable);
	}
}

static enum jump_label_type jump_label_type(struct static_key *key)
{
	bool true_branch = jump_label_get_branch_default(key);
	bool state = static_key_enabled(key);

	if ((!true_branch && state) || (true_branch && !state))
		return JUMP_LABEL_ENABLE;

	return JUMP_LABEL_DISABLE;
}

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;

	jump_label_lock();
	jump_label_sort_entries(iter_start, iter_stop);

	for (iter = iter_start; iter < iter_stop; iter++) {
		struct static_key *iterk;

		iterk = (struct static_key *)(unsigned long)iter->key;
		arch_jump_label_transform_static(iter, jump_label_type(iterk));
		if (iterk == key)
			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
	}
	jump_label_unlock();
}

#ifdef CONFIG_MODULES

struct static_key_mod {
	struct static_key_mod *next;
	struct jump_entry *entries;
	struct module *mod;
};

static int __jump_label_mod_text_reserved(void *start, void *end)
{
	struct module *mod;

	mod = __module_text_address((unsigned long)start);
	if (!mod)
		return 0;

	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);

	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, int enable)
{
	struct static_key_mod *mod = key->next;

	while (mod) {
		struct module *m = mod->mod;

		__jump_label_update(key, mod->entries,
				    m->jump_entries + m->num_jump_entries,
				    enable);
		mod = mod->next;
	}
}

/***
 * 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++) {
		arch_jump_label_transform_static(iter, JUMP_LABEL_DISABLE);
	}
}

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;

	/* 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 = (struct static_key *)(unsigned long)iter->key;
		if (iterk == key)
			continue;

		key = iterk;
		if (__module_address(iter->key) == mod) {
			/*
			 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
			 */
			*((unsigned long *)&key->entries) += (unsigned long)iter;
			key->next = NULL;
			continue;
		}
		jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
		if (!jlm)
			return -ENOMEM;
		jlm->mod = mod;
		jlm->entries = iter;
		jlm->next = key->next;
		key->next = jlm;

		if (jump_label_type(key) == JUMP_LABEL_ENABLE)
			__jump_label_update(key, iter, iter_stop, JUMP_LABEL_ENABLE);
	}

	return 0;
}

static void jump_label_del_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, **prev;

	for (iter = iter_start; iter < iter_stop; iter++) {
		if (iter->key == (jump_label_t)(unsigned long)key)
			continue;

		key = (struct static_key *)(unsigned long)iter->key;

		if (__module_address(iter->key) == mod)
			continue;

		prev = &key->next;
		jlm = key->next;

		while (jlm && jlm->mod != mod) {
			prev = &jlm->next;
			jlm = jlm->next;
		}

		if (jlm) {
			*prev = jlm->next;
			kfree(jlm);
		}
	}
}

static void jump_label_invalidate_module_init(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;

	for (iter = iter_start; iter < iter_stop; iter++) {
		if (within_module_init(iter->code, mod))
			iter->code = 0;
	}
}

static int
jump_label_module_notify(struct notifier_block *self, unsigned long val,
			 void *data)
{
	struct module *mod = data;
	int ret = 0;

	switch (val) {
	case MODULE_STATE_COMING:
		jump_label_lock();
		ret = jump_label_add_module(mod);
		if (ret)
			jump_label_del_module(mod);
		jump_label_unlock();
		break;
	case MODULE_STATE_GOING:
		jump_label_lock();
		jump_label_del_module(mod);
		jump_label_unlock();
		break;
	case MODULE_STATE_LIVE:
		jump_label_lock();
		jump_label_invalidate_module_init(mod);
		jump_label_unlock();
		break;
	}

	return notifier_from_errno(ret);
}

struct notifier_block jump_label_module_nb = {
	.notifier_call = jump_label_module_notify,
	.priority = 1, /* higher than tracepoints */
};

static __init int jump_label_init_module(void)
{
	return register_module_notifier(&jump_label_module_nb);
}
early_initcall(jump_label_init_module);

#endif /* CONFIG_MODULES */

/***
 * 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;
}

static void jump_label_update(struct static_key *key, int enable)
{
	struct jump_entry *stop = __stop___jump_table;
	struct jump_entry *entry = jump_label_get_entries(key);

#ifdef CONFIG_MODULES
	struct module *mod = __module_address((unsigned long)key);

	__jump_label_mod_update(key, enable);

	if (mod)
		stop = mod->jump_entries + mod->num_jump_entries;
#endif
	/* if there are no users, entry can be NULL */
	if (entry)
		__jump_label_update(key, entry, stop, enable);
}

#endif
Commit	Line	Data
bf5438fc JB	1	/*
	2	* jump label support
	3	*
	4	* Copyright (C) 2009 Jason Baron <[email protected]>
d430d3d7	5	* Copyright (C) 2011 Peter Zijlstra <[email protected]>
bf5438fc JB	6	*
bf5438fc JB	7	*/
bf5438fc JB	8	#include <linux/memory.h>
	9	#include <linux/uaccess.h>
	10	#include <linux/module.h>
	11	#include <linux/list.h>
bf5438fc JB	12	#include <linux/slab.h>
	13	#include <linux/sort.h>
	14	#include <linux/err.h>
c5905afb	15	#include <linux/static_key.h>
bf5438fc JB	16
	17	#ifdef HAVE_JUMP_LABEL
	18
bf5438fc JB	19	/* mutex to protect coming/going of the the jump_label table */
	20	static DEFINE_MUTEX(jump_label_mutex);
	21
91bad2f8 JB	22	void jump_label_lock(void)
	23	{
	24	mutex_lock(&jump_label_mutex);
	25	}
	26
	27	void jump_label_unlock(void)
	28	{
	29	mutex_unlock(&jump_label_mutex);
	30	}
	31
bf5438fc JB	32	static int jump_label_cmp(const void a, const void b)
	33	{
	34	const struct jump_entry *jea = a;
	35	const struct jump_entry *jeb = b;
	36
	37	if (jea->key < jeb->key)
	38	return -1;
	39
	40	if (jea->key > jeb->key)
	41	return 1;
	42
	43	return 0;
	44	}
	45
	46	static void
d430d3d7	47	jump_label_sort_entries(struct jump_entry start, struct jump_entry stop)
bf5438fc JB	48	{
	49	unsigned long size;
	50
	51	size = (((unsigned long)stop - (unsigned long)start)
	52	/ sizeof(struct jump_entry));
	53	sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
	54	}
	55
c5905afb	56	static void jump_label_update(struct static_key *key, int enable);
bf5438fc	57
c5905afb	58	void static_key_slow_inc(struct static_key *key)
bf5438fc	59	{
d430d3d7 JB	60	if (atomic_inc_not_zero(&key->enabled))
d430d3d7 JB	61	return;
bf5438fc	62
d430d3d7	63	jump_label_lock();
c5905afb IM	64	if (atomic_read(&key->enabled) == 0) {
	65	if (!jump_label_get_branch_default(key))
	66	jump_label_update(key, JUMP_LABEL_ENABLE);
	67	else
	68	jump_label_update(key, JUMP_LABEL_DISABLE);
	69	}
bbbf7af4	70	atomic_inc(&key->enabled);
d430d3d7	71	jump_label_unlock();
bf5438fc	72	}
c5905afb	73	EXPORT_SYMBOL_GPL(static_key_slow_inc);
bf5438fc	74
c5905afb	75	static void __static_key_slow_dec(struct static_key *key,
b2029520	76	unsigned long rate_limit, struct delayed_work *work)
bf5438fc	77	{
fadf0464 JB	78	if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
	79	WARN(atomic_read(&key->enabled) < 0,
	80	"jump label: negative count!\n");
d430d3d7	81	return;
fadf0464	82	}
bf5438fc	83
b2029520 GN	84	if (rate_limit) {
	85	atomic_inc(&key->enabled);
	86	schedule_delayed_work(work, rate_limit);
c5905afb IM	87	} else {
	88	if (!jump_label_get_branch_default(key))
	89	jump_label_update(key, JUMP_LABEL_DISABLE);
	90	else
	91	jump_label_update(key, JUMP_LABEL_ENABLE);
	92	}
91bad2f8	93	jump_label_unlock();
bf5438fc JB	94	}
bf5438fc JB	95
b2029520 GN	96	static void jump_label_update_timeout(struct work_struct *work)
b2029520 GN	97	{
c5905afb IM	98	struct static_key_deferred *key =
	99	container_of(work, struct static_key_deferred, work.work);
	100	__static_key_slow_dec(&key->key, 0, NULL);
b2029520 GN	101	}
b2029520 GN	102
c5905afb	103	void static_key_slow_dec(struct static_key *key)
b2029520	104	{
c5905afb	105	__static_key_slow_dec(key, 0, NULL);
b2029520	106	}
c5905afb	107	EXPORT_SYMBOL_GPL(static_key_slow_dec);
b2029520	108
c5905afb	109	void static_key_slow_dec_deferred(struct static_key_deferred *key)
b2029520	110	{
c5905afb	111	__static_key_slow_dec(&key->key, key->timeout, &key->work);
b2029520	112	}
c5905afb	113	EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
b2029520	114
c5905afb	115	void jump_label_rate_limit(struct static_key_deferred *key,
b2029520 GN	116	unsigned long rl)
	117	{
	118	key->timeout = rl;
	119	INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
	120	}
a181dc14	121	EXPORT_SYMBOL_GPL(jump_label_rate_limit);
b2029520	122
4c3ef6d7 JB	123	static int addr_conflict(struct jump_entry entry, void start, void *end)
	124	{
	125	if (entry->code <= (unsigned long)end &&
	126	entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
	127	return 1;
	128
	129	return 0;
	130	}
	131
d430d3d7 JB	132	static int __jump_label_text_reserved(struct jump_entry *iter_start,
d430d3d7 JB	133	struct jump_entry iter_stop, void start, void *end)
4c3ef6d7	134	{
4c3ef6d7	135	struct jump_entry *iter;
4c3ef6d7	136
4c3ef6d7 JB	137	iter = iter_start;
4c3ef6d7 JB	138	while (iter < iter_stop) {
d430d3d7 JB	139	if (addr_conflict(iter, start, end))
d430d3d7 JB	140	return 1;
4c3ef6d7 JB	141	iter++;
	142	}
	143
d430d3d7 JB	144	return 0;
	145	}
	146
20284aa7 JF	147	/*
	148	* Update code which is definitely not currently executing.
	149	* Architectures which need heavyweight synchronization to modify
	150	* running code can override this to make the non-live update case
	151	* cheaper.
	152	*/
9cdbe1cb	153	void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
20284aa7 JF	154	enum jump_label_type type)
	155	{
	156	arch_jump_label_transform(entry, type);
	157	}
	158
c5905afb	159	static void __jump_label_update(struct static_key *key,
7cbc5b8d JO	160	struct jump_entry *entry,
7cbc5b8d JO	161	struct jump_entry *stop, int enable)
d430d3d7	162	{
7cbc5b8d JO	163	for (; (entry < stop) &&
	164	(entry->key == (jump_label_t)(unsigned long)key);
	165	entry++) {
d430d3d7 JB	166	/*
	167	* entry->code set to 0 invalidates module init text sections
	168	* kernel_text_address() verifies we are not in core kernel
	169	* init code, see jump_label_invalidate_module_init().
	170	*/
	171	if (entry->code && kernel_text_address(entry->code))
	172	arch_jump_label_transform(entry, enable);
	173	}
4c3ef6d7 JB	174	}
4c3ef6d7 JB	175
c5905afb IM	176	static enum jump_label_type jump_label_type(struct static_key *key)
	177	{
	178	bool true_branch = jump_label_get_branch_default(key);
	179	bool state = static_key_enabled(key);
	180
	181	if ((!true_branch && state) \|\| (true_branch && !state))
	182	return JUMP_LABEL_ENABLE;
	183
	184	return JUMP_LABEL_DISABLE;
	185	}
	186
97ce2c88	187	void __init jump_label_init(void)
bf5438fc	188	{
bf5438fc JB	189	struct jump_entry *iter_start = __start___jump_table;
bf5438fc JB	190	struct jump_entry *iter_stop = __stop___jump_table;
c5905afb	191	struct static_key *key = NULL;
bf5438fc JB	192	struct jump_entry *iter;
bf5438fc JB	193
91bad2f8	194	jump_label_lock();
d430d3d7 JB	195	jump_label_sort_entries(iter_start, iter_stop);
	196
	197	for (iter = iter_start; iter < iter_stop; iter++) {
c5905afb	198	struct static_key *iterk;
37348804	199
c5905afb IM	200	iterk = (struct static_key *)(unsigned long)iter->key;
c5905afb IM	201	arch_jump_label_transform_static(iter, jump_label_type(iterk));
37348804	202	if (iterk == key)
d430d3d7 JB	203	continue;
d430d3d7 JB	204
37348804	205	key = iterk;
c5905afb IM	206	/*
	207	* Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
	208	*/
	209	((unsigned long )&key->entries) += (unsigned long)iter;
d430d3d7 JB	210	#ifdef CONFIG_MODULES
	211	key->next = NULL;
	212	#endif
bf5438fc	213	}
91bad2f8	214	jump_label_unlock();
bf5438fc	215	}
bf5438fc JB	216
	217	#ifdef CONFIG_MODULES
	218
c5905afb IM	219	struct static_key_mod {
c5905afb IM	220	struct static_key_mod *next;
d430d3d7 JB	221	struct jump_entry *entries;
	222	struct module *mod;
	223	};
	224
	225	static int __jump_label_mod_text_reserved(void start, void end)
	226	{
	227	struct module *mod;
	228
	229	mod = __module_text_address((unsigned long)start);
	230	if (!mod)
	231	return 0;
	232
	233	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
	234
	235	return __jump_label_text_reserved(mod->jump_entries,
	236	mod->jump_entries + mod->num_jump_entries,
	237	start, end);
	238	}
	239
c5905afb	240	static void __jump_label_mod_update(struct static_key *key, int enable)
d430d3d7	241	{
c5905afb	242	struct static_key_mod *mod = key->next;
d430d3d7 JB	243
d430d3d7 JB	244	while (mod) {
7cbc5b8d JO	245	struct module *m = mod->mod;
	246
	247	__jump_label_update(key, mod->entries,
	248	m->jump_entries + m->num_jump_entries,
	249	enable);
d430d3d7 JB	250	mod = mod->next;
	251	}
	252	}
	253
	254	/***
	255	* apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
	256	* @mod: module to patch
	257	*
	258	* Allow for run-time selection of the optimal nops. Before the module
	259	* loads patch these with arch_get_jump_label_nop(), which is specified by
	260	* the arch specific jump label code.
	261	*/
	262	void jump_label_apply_nops(struct module *mod)
bf5438fc	263	{
d430d3d7 JB	264	struct jump_entry *iter_start = mod->jump_entries;
	265	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	266	struct jump_entry *iter;
	267
	268	/* if the module doesn't have jump label entries, just return */
	269	if (iter_start == iter_stop)
	270	return;
	271
ac99b862	272	for (iter = iter_start; iter < iter_stop; iter++) {
c5905afb	273	arch_jump_label_transform_static(iter, JUMP_LABEL_DISABLE);
ac99b862	274	}
bf5438fc JB	275	}
bf5438fc JB	276
d430d3d7	277	static int jump_label_add_module(struct module *mod)
bf5438fc	278	{
d430d3d7 JB	279	struct jump_entry *iter_start = mod->jump_entries;
	280	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	281	struct jump_entry *iter;
c5905afb IM	282	struct static_key *key = NULL;
c5905afb IM	283	struct static_key_mod *jlm;
bf5438fc JB	284
bf5438fc JB	285	/* if the module doesn't have jump label entries, just return */
d430d3d7	286	if (iter_start == iter_stop)
bf5438fc JB	287	return 0;
bf5438fc JB	288
d430d3d7 JB	289	jump_label_sort_entries(iter_start, iter_stop);
	290
	291	for (iter = iter_start; iter < iter_stop; iter++) {
c5905afb	292	struct static_key *iterk;
d430d3d7	293
c5905afb IM	294	iterk = (struct static_key *)(unsigned long)iter->key;
	295	if (iterk == key)
	296	continue;
d430d3d7	297
c5905afb	298	key = iterk;
d430d3d7	299	if (__module_address(iter->key) == mod) {
c5905afb IM	300	/*
	301	* Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
	302	*/
	303	((unsigned long )&key->entries) += (unsigned long)iter;
d430d3d7 JB	304	key->next = NULL;
d430d3d7 JB	305	continue;
bf5438fc	306	}
c5905afb	307	jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
d430d3d7 JB	308	if (!jlm)
d430d3d7 JB	309	return -ENOMEM;
d430d3d7 JB	310	jlm->mod = mod;
	311	jlm->entries = iter;
	312	jlm->next = key->next;
	313	key->next = jlm;
	314
c5905afb	315	if (jump_label_type(key) == JUMP_LABEL_ENABLE)
ac99b862	316	__jump_label_update(key, iter, iter_stop, JUMP_LABEL_ENABLE);
bf5438fc	317	}
d430d3d7	318
bf5438fc JB	319	return 0;
	320	}
	321
d430d3d7	322	static void jump_label_del_module(struct module *mod)
bf5438fc	323	{
d430d3d7 JB	324	struct jump_entry *iter_start = mod->jump_entries;
	325	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	326	struct jump_entry *iter;
c5905afb IM	327	struct static_key *key = NULL;
c5905afb IM	328	struct static_key_mod jlm, *prev;
bf5438fc	329
d430d3d7 JB	330	for (iter = iter_start; iter < iter_stop; iter++) {
	331	if (iter->key == (jump_label_t)(unsigned long)key)
	332	continue;
	333
c5905afb	334	key = (struct static_key *)(unsigned long)iter->key;
d430d3d7 JB	335
	336	if (__module_address(iter->key) == mod)
	337	continue;
	338
	339	prev = &key->next;
	340	jlm = key->next;
bf5438fc	341
d430d3d7 JB	342	while (jlm && jlm->mod != mod) {
	343	prev = &jlm->next;
	344	jlm = jlm->next;
	345	}
	346
	347	if (jlm) {
	348	*prev = jlm->next;
	349	kfree(jlm);
bf5438fc JB	350	}
	351	}
	352	}
	353
d430d3d7	354	static void jump_label_invalidate_module_init(struct module *mod)
b842f8fa	355	{
d430d3d7 JB	356	struct jump_entry *iter_start = mod->jump_entries;
d430d3d7 JB	357	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
b842f8fa	358	struct jump_entry *iter;
b842f8fa	359
d430d3d7 JB	360	for (iter = iter_start; iter < iter_stop; iter++) {
	361	if (within_module_init(iter->code, mod))
	362	iter->code = 0;
b842f8fa JB	363	}
	364	}
	365
bf5438fc JB	366	static int
	367	jump_label_module_notify(struct notifier_block *self, unsigned long val,
	368	void *data)
	369	{
	370	struct module *mod = data;
	371	int ret = 0;
	372
	373	switch (val) {
	374	case MODULE_STATE_COMING:
91bad2f8	375	jump_label_lock();
d430d3d7	376	ret = jump_label_add_module(mod);
bf5438fc	377	if (ret)
d430d3d7	378	jump_label_del_module(mod);
91bad2f8	379	jump_label_unlock();
bf5438fc JB	380	break;
bf5438fc JB	381	case MODULE_STATE_GOING:
91bad2f8	382	jump_label_lock();
d430d3d7	383	jump_label_del_module(mod);
91bad2f8	384	jump_label_unlock();
bf5438fc	385	break;
b842f8fa	386	case MODULE_STATE_LIVE:
91bad2f8	387	jump_label_lock();
d430d3d7	388	jump_label_invalidate_module_init(mod);
91bad2f8	389	jump_label_unlock();
b842f8fa	390	break;
bf5438fc	391	}
bf5438fc	392
d430d3d7	393	return notifier_from_errno(ret);
bf5438fc JB	394	}
	395
	396	struct notifier_block jump_label_module_nb = {
	397	.notifier_call = jump_label_module_notify,
d430d3d7	398	.priority = 1, /* higher than tracepoints */
bf5438fc JB	399	};
bf5438fc JB	400
d430d3d7	401	static __init int jump_label_init_module(void)
bf5438fc JB	402	{
	403	return register_module_notifier(&jump_label_module_nb);
	404	}
d430d3d7	405	early_initcall(jump_label_init_module);
bf5438fc JB	406
	407	#endif /* CONFIG_MODULES */
	408
d430d3d7 JB	409	/***
	410	* jump_label_text_reserved - check if addr range is reserved
	411	* @start: start text addr
	412	* @end: end text addr
	413	*
	414	* checks if the text addr located between @start and @end
	415	* overlaps with any of the jump label patch addresses. Code
	416	* that wants to modify kernel text should first verify that
	417	* it does not overlap with any of the jump label addresses.
	418	* Caller must hold jump_label_mutex.
	419	*
	420	* returns 1 if there is an overlap, 0 otherwise
	421	*/
	422	int jump_label_text_reserved(void start, void end)
	423	{
	424	int ret = __jump_label_text_reserved(__start___jump_table,
	425	__stop___jump_table, start, end);
	426
	427	if (ret)
	428	return ret;
	429
	430	#ifdef CONFIG_MODULES
	431	ret = __jump_label_mod_text_reserved(start, end);
	432	#endif
	433	return ret;
	434	}
	435
c5905afb	436	static void jump_label_update(struct static_key *key, int enable)
d430d3d7	437	{
c5905afb IM	438	struct jump_entry *stop = __stop___jump_table;
c5905afb IM	439	struct jump_entry *entry = jump_label_get_entries(key);
d430d3d7 JB	440
d430d3d7 JB	441	#ifdef CONFIG_MODULES
a746e3cc	442	struct module *mod = __module_address((unsigned long)key);
140fe3b1	443
d430d3d7	444	__jump_label_mod_update(key, enable);
140fe3b1 XG	445
	446	if (mod)
	447	stop = mod->jump_entries + mod->num_jump_entries;
d430d3d7	448	#endif
140fe3b1 XG	449	/* if there are no users, entry can be NULL */
	450	if (entry)
	451	__jump_label_update(key, entry, stop, enable);
d430d3d7 JB	452	}
d430d3d7 JB	453
bf5438fc	454	#endif