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