[linux-2.6-block.git] / kernel / jump_label.c

/*
 * jump label support
 *
 * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
 * Copyright (C) 2011 Peter Zijlstra <pzijlstr@redhat.com>
 *
 */
#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/jump_label.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);
}

bool jump_label_enabled(struct jump_label_key *key)
{
	return !!atomic_read(&key->enabled);
}

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 jump_label_key *key, int enable);

void jump_label_inc(struct jump_label_key *key)
{
	if (atomic_inc_not_zero(&key->enabled))
		return;

	jump_label_lock();
	if (atomic_read(&key->enabled) == 0)
		jump_label_update(key, JUMP_LABEL_ENABLE);
	atomic_inc(&key->enabled);
	jump_label_unlock();
}
EXPORT_SYMBOL_GPL(jump_label_inc);

static void __jump_label_dec(struct jump_label_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
		jump_label_update(key, JUMP_LABEL_DISABLE);

	jump_label_unlock();
}
EXPORT_SYMBOL_GPL(jump_label_dec);

static void jump_label_update_timeout(struct work_struct *work)
{
	struct jump_label_key_deferred *key =
		container_of(work, struct jump_label_key_deferred, work.work);
	__jump_label_dec(&key->key, 0, NULL);
}

void jump_label_dec(struct jump_label_key *key)
{
	__jump_label_dec(key, 0, NULL);
}

void jump_label_dec_deferred(struct jump_label_key_deferred *key)
{
	__jump_label_dec(&key->key, key->timeout, &key->work);
}


void jump_label_rate_limit(struct jump_label_key_deferred *key,
		unsigned long rl)
{
	key->timeout = rl;
	INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
}

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 jump_label_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);
	}
}

void __init jump_label_init(void)
{
	struct jump_entry *iter_start = __start___jump_table;
	struct jump_entry *iter_stop = __stop___jump_table;
	struct jump_label_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 jump_label_key *iterk;

		iterk = (struct jump_label_key *)(unsigned long)iter->key;
		arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ?
						 JUMP_LABEL_ENABLE : JUMP_LABEL_DISABLE);
		if (iterk == key)
			continue;

		key = iterk;
		key->entries = iter;
#ifdef CONFIG_MODULES
		key->next = NULL;
#endif
	}
	jump_label_unlock();
}

#ifdef CONFIG_MODULES

struct jump_label_mod {
	struct jump_label_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 jump_label_key *key, int enable)
{
	struct jump_label_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++) {
		struct jump_label_key *iterk;

		iterk = (struct jump_label_key *)(unsigned long)iter->key;
		arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ?
				JUMP_LABEL_ENABLE : 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 jump_label_key *key = NULL;
	struct jump_label_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++) {
		if (iter->key == (jump_label_t)(unsigned long)key)
			continue;

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

		if (__module_address(iter->key) == mod) {
			atomic_set(&key->enabled, 0);
			key->entries = iter;
			key->next = NULL;
			continue;
		}

		jlm = kzalloc(sizeof(struct jump_label_mod), GFP_KERNEL);
		if (!jlm)
			return -ENOMEM;

		jlm->mod = mod;
		jlm->entries = iter;
		jlm->next = key->next;
		key->next = jlm;

		if (jump_label_enabled(key))
			__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 jump_label_key *key = NULL;
	struct jump_label_mod *jlm, **prev;

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

		key = (struct jump_label_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 jump_label_key *key, int enable)
{
	struct jump_entry *entry = key->entries, *stop = __stop___jump_table;

#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 <jbaron@redhat.com>
d430d3d7	5	* Copyright (C) 2011 Peter Zijlstra <pzijlstr@redhat.com>
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>
d430d3d7	15	#include <linux/jump_label.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
d430d3d7 JB	32	bool jump_label_enabled(struct jump_label_key *key)
	33	{
	34	return !!atomic_read(&key->enabled);
	35	}
	36
bf5438fc JB	37	static int jump_label_cmp(const void a, const void b)
	38	{
	39	const struct jump_entry *jea = a;
	40	const struct jump_entry *jeb = b;
	41
	42	if (jea->key < jeb->key)
	43	return -1;
	44
	45	if (jea->key > jeb->key)
	46	return 1;
	47
	48	return 0;
	49	}
	50
	51	static void
d430d3d7	52	jump_label_sort_entries(struct jump_entry start, struct jump_entry stop)
bf5438fc JB	53	{
	54	unsigned long size;
	55
	56	size = (((unsigned long)stop - (unsigned long)start)
	57	/ sizeof(struct jump_entry));
	58	sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
	59	}
	60
d430d3d7	61	static void jump_label_update(struct jump_label_key *key, int enable);
bf5438fc	62
d430d3d7	63	void jump_label_inc(struct jump_label_key *key)
bf5438fc	64	{
d430d3d7 JB	65	if (atomic_inc_not_zero(&key->enabled))
d430d3d7 JB	66	return;
bf5438fc	67
d430d3d7	68	jump_label_lock();
bbbf7af4	69	if (atomic_read(&key->enabled) == 0)
d430d3d7	70	jump_label_update(key, JUMP_LABEL_ENABLE);
bbbf7af4	71	atomic_inc(&key->enabled);
d430d3d7	72	jump_label_unlock();
bf5438fc	73	}
a65cf518	74	EXPORT_SYMBOL_GPL(jump_label_inc);
bf5438fc	75
b2029520 GN	76	static void __jump_label_dec(struct jump_label_key *key,
b2029520 GN	77	unsigned long rate_limit, struct delayed_work *work)
bf5438fc	78	{
fadf0464 JB	79	if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
	80	WARN(atomic_read(&key->enabled) < 0,
	81	"jump label: negative count!\n");
d430d3d7	82	return;
fadf0464	83	}
bf5438fc	84
b2029520 GN	85	if (rate_limit) {
	86	atomic_inc(&key->enabled);
	87	schedule_delayed_work(work, rate_limit);
	88	} else
	89	jump_label_update(key, JUMP_LABEL_DISABLE);
	90
91bad2f8	91	jump_label_unlock();
bf5438fc	92	}
a65cf518	93	EXPORT_SYMBOL_GPL(jump_label_dec);
bf5438fc	94
b2029520 GN	95	static void jump_label_update_timeout(struct work_struct *work)
	96	{
	97	struct jump_label_key_deferred *key =
	98	container_of(work, struct jump_label_key_deferred, work.work);
	99	__jump_label_dec(&key->key, 0, NULL);
	100	}
	101
	102	void jump_label_dec(struct jump_label_key *key)
	103	{
	104	__jump_label_dec(key, 0, NULL);
	105	}
	106
	107	void jump_label_dec_deferred(struct jump_label_key_deferred *key)
	108	{
	109	__jump_label_dec(&key->key, key->timeout, &key->work);
	110	}
	111
	112
	113	void jump_label_rate_limit(struct jump_label_key_deferred *key,
	114	unsigned long rl)
	115	{
	116	key->timeout = rl;
	117	INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
	118	}
	119
4c3ef6d7 JB	120	static int addr_conflict(struct jump_entry entry, void start, void *end)
	121	{
	122	if (entry->code <= (unsigned long)end &&
	123	entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
	124	return 1;
	125
	126	return 0;
	127	}
	128
d430d3d7 JB	129	static int __jump_label_text_reserved(struct jump_entry *iter_start,
d430d3d7 JB	130	struct jump_entry iter_stop, void start, void *end)
4c3ef6d7	131	{
4c3ef6d7	132	struct jump_entry *iter;
4c3ef6d7	133
4c3ef6d7 JB	134	iter = iter_start;
4c3ef6d7 JB	135	while (iter < iter_stop) {
d430d3d7 JB	136	if (addr_conflict(iter, start, end))
d430d3d7 JB	137	return 1;
4c3ef6d7 JB	138	iter++;
	139	}
	140
d430d3d7 JB	141	return 0;
	142	}
	143
20284aa7 JF	144	/*
	145	* Update code which is definitely not currently executing.
	146	* Architectures which need heavyweight synchronization to modify
	147	* running code can override this to make the non-live update case
	148	* cheaper.
	149	*/
9cdbe1cb	150	void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
20284aa7 JF	151	enum jump_label_type type)
	152	{
	153	arch_jump_label_transform(entry, type);
	154	}
	155
d430d3d7	156	static void __jump_label_update(struct jump_label_key *key,
7cbc5b8d JO	157	struct jump_entry *entry,
7cbc5b8d JO	158	struct jump_entry *stop, int enable)
d430d3d7	159	{
7cbc5b8d JO	160	for (; (entry < stop) &&
	161	(entry->key == (jump_label_t)(unsigned long)key);
	162	entry++) {
d430d3d7 JB	163	/*
	164	* entry->code set to 0 invalidates module init text sections
	165	* kernel_text_address() verifies we are not in core kernel
	166	* init code, see jump_label_invalidate_module_init().
	167	*/
	168	if (entry->code && kernel_text_address(entry->code))
	169	arch_jump_label_transform(entry, enable);
	170	}
4c3ef6d7 JB	171	}
4c3ef6d7 JB	172
97ce2c88	173	void __init jump_label_init(void)
bf5438fc	174	{
bf5438fc JB	175	struct jump_entry *iter_start = __start___jump_table;
bf5438fc JB	176	struct jump_entry *iter_stop = __stop___jump_table;
d430d3d7	177	struct jump_label_key *key = NULL;
bf5438fc JB	178	struct jump_entry *iter;
bf5438fc JB	179
91bad2f8	180	jump_label_lock();
d430d3d7 JB	181	jump_label_sort_entries(iter_start, iter_stop);
	182
	183	for (iter = iter_start; iter < iter_stop; iter++) {
37348804 JF	184	struct jump_label_key *iterk;
	185
	186	iterk = (struct jump_label_key *)(unsigned long)iter->key;
20284aa7 JF	187	arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ?
20284aa7 JF	188	JUMP_LABEL_ENABLE : JUMP_LABEL_DISABLE);
37348804	189	if (iterk == key)
d430d3d7 JB	190	continue;
d430d3d7 JB	191
37348804	192	key = iterk;
d430d3d7 JB	193	key->entries = iter;
	194	#ifdef CONFIG_MODULES
	195	key->next = NULL;
	196	#endif
bf5438fc	197	}
91bad2f8	198	jump_label_unlock();
bf5438fc	199	}
bf5438fc JB	200
	201	#ifdef CONFIG_MODULES
	202
d430d3d7 JB	203	struct jump_label_mod {
	204	struct jump_label_mod *next;
	205	struct jump_entry *entries;
	206	struct module *mod;
	207	};
	208
	209	static int __jump_label_mod_text_reserved(void start, void end)
	210	{
	211	struct module *mod;
	212
	213	mod = __module_text_address((unsigned long)start);
	214	if (!mod)
	215	return 0;
	216
	217	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
	218
	219	return __jump_label_text_reserved(mod->jump_entries,
	220	mod->jump_entries + mod->num_jump_entries,
	221	start, end);
	222	}
	223
	224	static void __jump_label_mod_update(struct jump_label_key *key, int enable)
	225	{
	226	struct jump_label_mod *mod = key->next;
	227
	228	while (mod) {
7cbc5b8d JO	229	struct module *m = mod->mod;
	230
	231	__jump_label_update(key, mod->entries,
	232	m->jump_entries + m->num_jump_entries,
	233	enable);
d430d3d7 JB	234	mod = mod->next;
	235	}
	236	}
	237
	238	/***
	239	* apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
	240	* @mod: module to patch
	241	*
	242	* Allow for run-time selection of the optimal nops. Before the module
	243	* loads patch these with arch_get_jump_label_nop(), which is specified by
	244	* the arch specific jump label code.
	245	*/
	246	void jump_label_apply_nops(struct module *mod)
bf5438fc	247	{
d430d3d7 JB	248	struct jump_entry *iter_start = mod->jump_entries;
	249	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	250	struct jump_entry *iter;
	251
	252	/* if the module doesn't have jump label entries, just return */
	253	if (iter_start == iter_stop)
	254	return;
	255
ac99b862 PZ	256	for (iter = iter_start; iter < iter_stop; iter++) {
	257	struct jump_label_key *iterk;
	258
	259	iterk = (struct jump_label_key *)(unsigned long)iter->key;
	260	arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ?
	261	JUMP_LABEL_ENABLE : JUMP_LABEL_DISABLE);
	262	}
bf5438fc JB	263	}
bf5438fc JB	264
d430d3d7	265	static int jump_label_add_module(struct module *mod)
bf5438fc	266	{
d430d3d7 JB	267	struct jump_entry *iter_start = mod->jump_entries;
	268	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	269	struct jump_entry *iter;
	270	struct jump_label_key *key = NULL;
	271	struct jump_label_mod *jlm;
bf5438fc JB	272
bf5438fc JB	273	/* if the module doesn't have jump label entries, just return */
d430d3d7	274	if (iter_start == iter_stop)
bf5438fc JB	275	return 0;
bf5438fc JB	276
d430d3d7 JB	277	jump_label_sort_entries(iter_start, iter_stop);
	278
	279	for (iter = iter_start; iter < iter_stop; iter++) {
	280	if (iter->key == (jump_label_t)(unsigned long)key)
	281	continue;
	282
	283	key = (struct jump_label_key *)(unsigned long)iter->key;
	284
	285	if (__module_address(iter->key) == mod) {
	286	atomic_set(&key->enabled, 0);
	287	key->entries = iter;
	288	key->next = NULL;
	289	continue;
bf5438fc	290	}
d430d3d7 JB	291
	292	jlm = kzalloc(sizeof(struct jump_label_mod), GFP_KERNEL);
	293	if (!jlm)
	294	return -ENOMEM;
	295
	296	jlm->mod = mod;
	297	jlm->entries = iter;
	298	jlm->next = key->next;
	299	key->next = jlm;
	300
	301	if (jump_label_enabled(key))
ac99b862	302	__jump_label_update(key, iter, iter_stop, JUMP_LABEL_ENABLE);
bf5438fc	303	}
d430d3d7	304
bf5438fc JB	305	return 0;
	306	}
	307
d430d3d7	308	static void jump_label_del_module(struct module *mod)
bf5438fc	309	{
d430d3d7 JB	310	struct jump_entry *iter_start = mod->jump_entries;
	311	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	312	struct jump_entry *iter;
	313	struct jump_label_key *key = NULL;
	314	struct jump_label_mod jlm, *prev;
bf5438fc	315
d430d3d7 JB	316	for (iter = iter_start; iter < iter_stop; iter++) {
	317	if (iter->key == (jump_label_t)(unsigned long)key)
	318	continue;
	319
	320	key = (struct jump_label_key *)(unsigned long)iter->key;
	321
	322	if (__module_address(iter->key) == mod)
	323	continue;
	324
	325	prev = &key->next;
	326	jlm = key->next;
bf5438fc	327
d430d3d7 JB	328	while (jlm && jlm->mod != mod) {
	329	prev = &jlm->next;
	330	jlm = jlm->next;
	331	}
	332
	333	if (jlm) {
	334	*prev = jlm->next;
	335	kfree(jlm);
bf5438fc JB	336	}
	337	}
	338	}
	339
d430d3d7	340	static void jump_label_invalidate_module_init(struct module *mod)
b842f8fa	341	{
d430d3d7 JB	342	struct jump_entry *iter_start = mod->jump_entries;
d430d3d7 JB	343	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
b842f8fa	344	struct jump_entry *iter;
b842f8fa	345
d430d3d7 JB	346	for (iter = iter_start; iter < iter_stop; iter++) {
	347	if (within_module_init(iter->code, mod))
	348	iter->code = 0;
b842f8fa JB	349	}
	350	}
	351
bf5438fc JB	352	static int
	353	jump_label_module_notify(struct notifier_block *self, unsigned long val,
	354	void *data)
	355	{
	356	struct module *mod = data;
	357	int ret = 0;
	358
	359	switch (val) {
	360	case MODULE_STATE_COMING:
91bad2f8	361	jump_label_lock();
d430d3d7	362	ret = jump_label_add_module(mod);
bf5438fc	363	if (ret)
d430d3d7	364	jump_label_del_module(mod);
91bad2f8	365	jump_label_unlock();
bf5438fc JB	366	break;
bf5438fc JB	367	case MODULE_STATE_GOING:
91bad2f8	368	jump_label_lock();
d430d3d7	369	jump_label_del_module(mod);
91bad2f8	370	jump_label_unlock();
bf5438fc	371	break;
b842f8fa	372	case MODULE_STATE_LIVE:
91bad2f8	373	jump_label_lock();
d430d3d7	374	jump_label_invalidate_module_init(mod);
91bad2f8	375	jump_label_unlock();
b842f8fa	376	break;
bf5438fc	377	}
bf5438fc	378
d430d3d7	379	return notifier_from_errno(ret);
bf5438fc JB	380	}
	381
	382	struct notifier_block jump_label_module_nb = {
	383	.notifier_call = jump_label_module_notify,
d430d3d7	384	.priority = 1, /* higher than tracepoints */
bf5438fc JB	385	};
bf5438fc JB	386
d430d3d7	387	static __init int jump_label_init_module(void)
bf5438fc JB	388	{
	389	return register_module_notifier(&jump_label_module_nb);
	390	}
d430d3d7	391	early_initcall(jump_label_init_module);
bf5438fc JB	392
	393	#endif /* CONFIG_MODULES */
	394
d430d3d7 JB	395	/***
	396	* jump_label_text_reserved - check if addr range is reserved
	397	* @start: start text addr
	398	* @end: end text addr
	399	*
	400	* checks if the text addr located between @start and @end
	401	* overlaps with any of the jump label patch addresses. Code
	402	* that wants to modify kernel text should first verify that
	403	* it does not overlap with any of the jump label addresses.
	404	* Caller must hold jump_label_mutex.
	405	*
	406	* returns 1 if there is an overlap, 0 otherwise
	407	*/
	408	int jump_label_text_reserved(void start, void end)
	409	{
	410	int ret = __jump_label_text_reserved(__start___jump_table,
	411	__stop___jump_table, start, end);
	412
	413	if (ret)
	414	return ret;
	415
	416	#ifdef CONFIG_MODULES
	417	ret = __jump_label_mod_text_reserved(start, end);
	418	#endif
	419	return ret;
	420	}
	421
	422	static void jump_label_update(struct jump_label_key *key, int enable)
	423	{
140fe3b1	424	struct jump_entry entry = key->entries, stop = __stop___jump_table;
d430d3d7 JB	425
d430d3d7 JB	426	#ifdef CONFIG_MODULES
a746e3cc	427	struct module *mod = __module_address((unsigned long)key);
140fe3b1	428
d430d3d7	429	__jump_label_mod_update(key, enable);
140fe3b1 XG	430
	431	if (mod)
	432	stop = mod->jump_entries + mod->num_jump_entries;
d430d3d7	433	#endif
140fe3b1 XG	434	/* if there are no users, entry can be NULL */
	435	if (entry)
	436	__jump_label_update(key, entry, stop, enable);
d430d3d7 JB	437	}
d430d3d7 JB	438
bf5438fc	439	#endif