[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>
#include <linux/jump_label_ratelimit.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>
851cf6e7	16	#include <linux/jump_label_ratelimit.h>
bf5438fc JB	17
	18	#ifdef HAVE_JUMP_LABEL
	19
bf5438fc JB	20	/* mutex to protect coming/going of the the jump_label table */
	21	static DEFINE_MUTEX(jump_label_mutex);
	22
91bad2f8 JB	23	void jump_label_lock(void)
	24	{
	25	mutex_lock(&jump_label_mutex);
	26	}
	27
	28	void jump_label_unlock(void)
	29	{
	30	mutex_unlock(&jump_label_mutex);
	31	}
	32
bf5438fc JB	33	static int jump_label_cmp(const void a, const void b)
	34	{
	35	const struct jump_entry *jea = a;
	36	const struct jump_entry *jeb = b;
	37
	38	if (jea->key < jeb->key)
	39	return -1;
	40
	41	if (jea->key > jeb->key)
	42	return 1;
	43
	44	return 0;
	45	}
	46
	47	static void
d430d3d7	48	jump_label_sort_entries(struct jump_entry start, struct jump_entry stop)
bf5438fc JB	49	{
	50	unsigned long size;
	51
	52	size = (((unsigned long)stop - (unsigned long)start)
	53	/ sizeof(struct jump_entry));
	54	sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
	55	}
	56
c5905afb	57	static void jump_label_update(struct static_key *key, int enable);
bf5438fc	58
c5905afb	59	void static_key_slow_inc(struct static_key *key)
bf5438fc	60	{
d430d3d7 JB	61	if (atomic_inc_not_zero(&key->enabled))
d430d3d7 JB	62	return;
bf5438fc	63
d430d3d7	64	jump_label_lock();
c5905afb IM	65	if (atomic_read(&key->enabled) == 0) {
	66	if (!jump_label_get_branch_default(key))
	67	jump_label_update(key, JUMP_LABEL_ENABLE);
	68	else
	69	jump_label_update(key, JUMP_LABEL_DISABLE);
	70	}
bbbf7af4	71	atomic_inc(&key->enabled);
d430d3d7	72	jump_label_unlock();
bf5438fc	73	}
c5905afb	74	EXPORT_SYMBOL_GPL(static_key_slow_inc);
bf5438fc	75
c5905afb	76	static void __static_key_slow_dec(struct static_key *key,
b2029520	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);
c5905afb IM	88	} else {
	89	if (!jump_label_get_branch_default(key))
	90	jump_label_update(key, JUMP_LABEL_DISABLE);
	91	else
	92	jump_label_update(key, JUMP_LABEL_ENABLE);
	93	}
91bad2f8	94	jump_label_unlock();
bf5438fc JB	95	}
bf5438fc JB	96
b2029520 GN	97	static void jump_label_update_timeout(struct work_struct *work)
b2029520 GN	98	{
c5905afb IM	99	struct static_key_deferred *key =
	100	container_of(work, struct static_key_deferred, work.work);
	101	__static_key_slow_dec(&key->key, 0, NULL);
b2029520 GN	102	}
b2029520 GN	103
c5905afb	104	void static_key_slow_dec(struct static_key *key)
b2029520	105	{
c5905afb	106	__static_key_slow_dec(key, 0, NULL);
b2029520	107	}
c5905afb	108	EXPORT_SYMBOL_GPL(static_key_slow_dec);
b2029520	109
c5905afb	110	void static_key_slow_dec_deferred(struct static_key_deferred *key)
b2029520	111	{
c5905afb	112	__static_key_slow_dec(&key->key, key->timeout, &key->work);
b2029520	113	}
c5905afb	114	EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
b2029520	115
c5905afb	116	void jump_label_rate_limit(struct static_key_deferred *key,
b2029520 GN	117	unsigned long rl)
	118	{
	119	key->timeout = rl;
	120	INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
	121	}
a181dc14	122	EXPORT_SYMBOL_GPL(jump_label_rate_limit);
b2029520	123
4c3ef6d7 JB	124	static int addr_conflict(struct jump_entry entry, void start, void *end)
	125	{
	126	if (entry->code <= (unsigned long)end &&
	127	entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
	128	return 1;
	129
	130	return 0;
	131	}
	132
d430d3d7 JB	133	static int __jump_label_text_reserved(struct jump_entry *iter_start,
d430d3d7 JB	134	struct jump_entry iter_stop, void start, void *end)
4c3ef6d7	135	{
4c3ef6d7	136	struct jump_entry *iter;
4c3ef6d7	137
4c3ef6d7 JB	138	iter = iter_start;
4c3ef6d7 JB	139	while (iter < iter_stop) {
d430d3d7 JB	140	if (addr_conflict(iter, start, end))
d430d3d7 JB	141	return 1;
4c3ef6d7 JB	142	iter++;
	143	}
	144
d430d3d7 JB	145	return 0;
	146	}
	147
20284aa7 JF	148	/*
	149	* Update code which is definitely not currently executing.
	150	* Architectures which need heavyweight synchronization to modify
	151	* running code can override this to make the non-live update case
	152	* cheaper.
	153	*/
9cdbe1cb	154	void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
20284aa7 JF	155	enum jump_label_type type)
	156	{
	157	arch_jump_label_transform(entry, type);
	158	}
	159
c5905afb	160	static void __jump_label_update(struct static_key *key,
7cbc5b8d JO	161	struct jump_entry *entry,
7cbc5b8d JO	162	struct jump_entry *stop, int enable)
d430d3d7	163	{
7cbc5b8d JO	164	for (; (entry < stop) &&
	165	(entry->key == (jump_label_t)(unsigned long)key);
	166	entry++) {
d430d3d7 JB	167	/*
	168	* entry->code set to 0 invalidates module init text sections
	169	* kernel_text_address() verifies we are not in core kernel
	170	* init code, see jump_label_invalidate_module_init().
	171	*/
	172	if (entry->code && kernel_text_address(entry->code))
	173	arch_jump_label_transform(entry, enable);
	174	}
4c3ef6d7 JB	175	}
4c3ef6d7 JB	176
c5905afb IM	177	static enum jump_label_type jump_label_type(struct static_key *key)
	178	{
	179	bool true_branch = jump_label_get_branch_default(key);
	180	bool state = static_key_enabled(key);
	181
	182	if ((!true_branch && state) \|\| (true_branch && !state))
	183	return JUMP_LABEL_ENABLE;
	184
	185	return JUMP_LABEL_DISABLE;
	186	}
	187
97ce2c88	188	void __init jump_label_init(void)
bf5438fc	189	{
bf5438fc JB	190	struct jump_entry *iter_start = __start___jump_table;
bf5438fc JB	191	struct jump_entry *iter_stop = __stop___jump_table;
c5905afb	192	struct static_key *key = NULL;
bf5438fc JB	193	struct jump_entry *iter;
bf5438fc JB	194
91bad2f8	195	jump_label_lock();
d430d3d7 JB	196	jump_label_sort_entries(iter_start, iter_stop);
	197
	198	for (iter = iter_start; iter < iter_stop; iter++) {
c5905afb	199	struct static_key *iterk;
37348804	200
c5905afb IM	201	iterk = (struct static_key *)(unsigned long)iter->key;
c5905afb IM	202	arch_jump_label_transform_static(iter, jump_label_type(iterk));
37348804	203	if (iterk == key)
d430d3d7 JB	204	continue;
d430d3d7 JB	205
37348804	206	key = iterk;
c5905afb IM	207	/*
	208	* Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
	209	*/
	210	((unsigned long )&key->entries) += (unsigned long)iter;
d430d3d7 JB	211	#ifdef CONFIG_MODULES
	212	key->next = NULL;
	213	#endif
bf5438fc	214	}
91bad2f8	215	jump_label_unlock();
bf5438fc	216	}
bf5438fc JB	217
	218	#ifdef CONFIG_MODULES
	219
c5905afb IM	220	struct static_key_mod {
c5905afb IM	221	struct static_key_mod *next;
d430d3d7 JB	222	struct jump_entry *entries;
	223	struct module *mod;
	224	};
	225
	226	static int __jump_label_mod_text_reserved(void start, void end)
	227	{
	228	struct module *mod;
	229
	230	mod = __module_text_address((unsigned long)start);
	231	if (!mod)
	232	return 0;
	233
	234	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
	235
	236	return __jump_label_text_reserved(mod->jump_entries,
	237	mod->jump_entries + mod->num_jump_entries,
	238	start, end);
	239	}
	240
c5905afb	241	static void __jump_label_mod_update(struct static_key *key, int enable)
d430d3d7	242	{
c5905afb	243	struct static_key_mod *mod = key->next;
d430d3d7 JB	244
d430d3d7 JB	245	while (mod) {
7cbc5b8d JO	246	struct module *m = mod->mod;
	247
	248	__jump_label_update(key, mod->entries,
	249	m->jump_entries + m->num_jump_entries,
	250	enable);
d430d3d7 JB	251	mod = mod->next;
	252	}
	253	}
	254
	255	/***
	256	* apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
	257	* @mod: module to patch
	258	*
	259	* Allow for run-time selection of the optimal nops. Before the module
	260	* loads patch these with arch_get_jump_label_nop(), which is specified by
	261	* the arch specific jump label code.
	262	*/
	263	void jump_label_apply_nops(struct module *mod)
bf5438fc	264	{
d430d3d7 JB	265	struct jump_entry *iter_start = mod->jump_entries;
	266	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	267	struct jump_entry *iter;
	268
	269	/* if the module doesn't have jump label entries, just return */
	270	if (iter_start == iter_stop)
	271	return;
	272
ac99b862	273	for (iter = iter_start; iter < iter_stop; iter++) {
c5905afb	274	arch_jump_label_transform_static(iter, JUMP_LABEL_DISABLE);
ac99b862	275	}
bf5438fc JB	276	}
bf5438fc JB	277
d430d3d7	278	static int jump_label_add_module(struct module *mod)
bf5438fc	279	{
d430d3d7 JB	280	struct jump_entry *iter_start = mod->jump_entries;
	281	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	282	struct jump_entry *iter;
c5905afb IM	283	struct static_key *key = NULL;
c5905afb IM	284	struct static_key_mod *jlm;
bf5438fc JB	285
bf5438fc JB	286	/* if the module doesn't have jump label entries, just return */
d430d3d7	287	if (iter_start == iter_stop)
bf5438fc JB	288	return 0;
bf5438fc JB	289
d430d3d7 JB	290	jump_label_sort_entries(iter_start, iter_stop);
	291
	292	for (iter = iter_start; iter < iter_stop; iter++) {
c5905afb	293	struct static_key *iterk;
d430d3d7	294
c5905afb IM	295	iterk = (struct static_key *)(unsigned long)iter->key;
	296	if (iterk == key)
	297	continue;
d430d3d7	298
c5905afb	299	key = iterk;
d430d3d7	300	if (__module_address(iter->key) == mod) {
c5905afb IM	301	/*
	302	* Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
	303	*/
	304	((unsigned long )&key->entries) += (unsigned long)iter;
d430d3d7 JB	305	key->next = NULL;
d430d3d7 JB	306	continue;
bf5438fc	307	}
c5905afb	308	jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
d430d3d7 JB	309	if (!jlm)
d430d3d7 JB	310	return -ENOMEM;
d430d3d7 JB	311	jlm->mod = mod;
	312	jlm->entries = iter;
	313	jlm->next = key->next;
	314	key->next = jlm;
	315
c5905afb	316	if (jump_label_type(key) == JUMP_LABEL_ENABLE)
ac99b862	317	__jump_label_update(key, iter, iter_stop, JUMP_LABEL_ENABLE);
bf5438fc	318	}
d430d3d7	319
bf5438fc JB	320	return 0;
	321	}
	322
d430d3d7	323	static void jump_label_del_module(struct module *mod)
bf5438fc	324	{
d430d3d7 JB	325	struct jump_entry *iter_start = mod->jump_entries;
	326	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
	327	struct jump_entry *iter;
c5905afb IM	328	struct static_key *key = NULL;
c5905afb IM	329	struct static_key_mod jlm, *prev;
bf5438fc	330
d430d3d7 JB	331	for (iter = iter_start; iter < iter_stop; iter++) {
	332	if (iter->key == (jump_label_t)(unsigned long)key)
	333	continue;
	334
c5905afb	335	key = (struct static_key *)(unsigned long)iter->key;
d430d3d7 JB	336
	337	if (__module_address(iter->key) == mod)
	338	continue;
	339
	340	prev = &key->next;
	341	jlm = key->next;
bf5438fc	342
d430d3d7 JB	343	while (jlm && jlm->mod != mod) {
	344	prev = &jlm->next;
	345	jlm = jlm->next;
	346	}
	347
	348	if (jlm) {
	349	*prev = jlm->next;
	350	kfree(jlm);
bf5438fc JB	351	}
	352	}
	353	}
	354
d430d3d7	355	static void jump_label_invalidate_module_init(struct module *mod)
b842f8fa	356	{
d430d3d7 JB	357	struct jump_entry *iter_start = mod->jump_entries;
d430d3d7 JB	358	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
b842f8fa	359	struct jump_entry *iter;
b842f8fa	360
d430d3d7 JB	361	for (iter = iter_start; iter < iter_stop; iter++) {
	362	if (within_module_init(iter->code, mod))
	363	iter->code = 0;
b842f8fa JB	364	}
	365	}
	366
bf5438fc JB	367	static int
	368	jump_label_module_notify(struct notifier_block *self, unsigned long val,
	369	void *data)
	370	{
	371	struct module *mod = data;
	372	int ret = 0;
	373
	374	switch (val) {
	375	case MODULE_STATE_COMING:
91bad2f8	376	jump_label_lock();
d430d3d7	377	ret = jump_label_add_module(mod);
bf5438fc	378	if (ret)
d430d3d7	379	jump_label_del_module(mod);
91bad2f8	380	jump_label_unlock();
bf5438fc JB	381	break;
bf5438fc JB	382	case MODULE_STATE_GOING:
91bad2f8	383	jump_label_lock();
d430d3d7	384	jump_label_del_module(mod);
91bad2f8	385	jump_label_unlock();
bf5438fc	386	break;
b842f8fa	387	case MODULE_STATE_LIVE:
91bad2f8	388	jump_label_lock();
d430d3d7	389	jump_label_invalidate_module_init(mod);
91bad2f8	390	jump_label_unlock();
b842f8fa	391	break;
bf5438fc	392	}
bf5438fc	393
d430d3d7	394	return notifier_from_errno(ret);
bf5438fc JB	395	}
	396
	397	struct notifier_block jump_label_module_nb = {
	398	.notifier_call = jump_label_module_notify,
d430d3d7	399	.priority = 1, /* higher than tracepoints */
bf5438fc JB	400	};
bf5438fc JB	401
d430d3d7	402	static __init int jump_label_init_module(void)
bf5438fc JB	403	{
	404	return register_module_notifier(&jump_label_module_nb);
	405	}
d430d3d7	406	early_initcall(jump_label_init_module);
bf5438fc JB	407
	408	#endif /* CONFIG_MODULES */
	409
d430d3d7 JB	410	/***
	411	* jump_label_text_reserved - check if addr range is reserved
	412	* @start: start text addr
	413	* @end: end text addr
	414	*
	415	* checks if the text addr located between @start and @end
	416	* overlaps with any of the jump label patch addresses. Code
	417	* that wants to modify kernel text should first verify that
	418	* it does not overlap with any of the jump label addresses.
	419	* Caller must hold jump_label_mutex.
	420	*
	421	* returns 1 if there is an overlap, 0 otherwise
	422	*/
	423	int jump_label_text_reserved(void start, void end)
	424	{
	425	int ret = __jump_label_text_reserved(__start___jump_table,
	426	__stop___jump_table, start, end);
	427
	428	if (ret)
	429	return ret;
	430
	431	#ifdef CONFIG_MODULES
	432	ret = __jump_label_mod_text_reserved(start, end);
	433	#endif
	434	return ret;
	435	}
	436
c5905afb	437	static void jump_label_update(struct static_key *key, int enable)
d430d3d7	438	{
c5905afb IM	439	struct jump_entry *stop = __stop___jump_table;
c5905afb IM	440	struct jump_entry *entry = jump_label_get_entries(key);
d430d3d7 JB	441
d430d3d7 JB	442	#ifdef CONFIG_MODULES
a746e3cc	443	struct module *mod = __module_address((unsigned long)key);
140fe3b1	444
d430d3d7	445	__jump_label_mod_update(key, enable);
140fe3b1 XG	446
	447	if (mod)
	448	stop = mod->jump_entries + mod->num_jump_entries;
d430d3d7	449	#endif
140fe3b1 XG	450	/* if there are no users, entry can be NULL */
	451	if (entry)
	452	__jump_label_update(key, entry, stop, enable);
d430d3d7 JB	453	}
d430d3d7 JB	454
bf5438fc	455	#endif