[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / jump_label.c

/*
 * jump label support
 *
 * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
 *
 */
#include <linux/jump_label.h>
#include <linux/memory.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/jhash.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/err.h>

#ifdef HAVE_JUMP_LABEL

#define JUMP_LABEL_HASH_BITS 6
#define JUMP_LABEL_TABLE_SIZE (1 << JUMP_LABEL_HASH_BITS)
static struct hlist_head jump_label_table[JUMP_LABEL_TABLE_SIZE];

/* mutex to protect coming/going of the the jump_label table */
static DEFINE_MUTEX(jump_label_mutex);

struct jump_label_entry {
	struct hlist_node hlist;
	struct jump_entry *table;
	int nr_entries;
	/* hang modules off here */
	struct hlist_head modules;
	unsigned long key;
};

struct jump_label_module_entry {
	struct hlist_node hlist;
	struct jump_entry *table;
	int nr_entries;
	struct module *mod;
};

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
sort_jump_label_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 struct jump_label_entry *get_jump_label_entry(jump_label_t key)
{
	struct hlist_head *head;
	struct hlist_node *node;
	struct jump_label_entry *e;
	u32 hash = jhash((void *)&key, sizeof(jump_label_t), 0);

	head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
	hlist_for_each_entry(e, node, head, hlist) {
		if (key == e->key)
			return e;
	}
	return NULL;
}

static struct jump_label_entry *
add_jump_label_entry(jump_label_t key, int nr_entries, struct jump_entry *table)
{
	struct hlist_head *head;
	struct jump_label_entry *e;
	u32 hash;

	e = get_jump_label_entry(key);
	if (e)
		return ERR_PTR(-EEXIST);

	e = kmalloc(sizeof(struct jump_label_entry), GFP_KERNEL);
	if (!e)
		return ERR_PTR(-ENOMEM);

	hash = jhash((void *)&key, sizeof(jump_label_t), 0);
	head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
	e->key = key;
	e->table = table;
	e->nr_entries = nr_entries;
	INIT_HLIST_HEAD(&(e->modules));
	hlist_add_head(&e->hlist, head);
	return e;
}

static int
build_jump_label_hashtable(struct jump_entry *start, struct jump_entry *stop)
{
	struct jump_entry *iter, *iter_begin;
	struct jump_label_entry *entry;
	int count;

	sort_jump_label_entries(start, stop);
	iter = start;
	while (iter < stop) {
		entry = get_jump_label_entry(iter->key);
		if (!entry) {
			iter_begin = iter;
			count = 0;
			while ((iter < stop) &&
				(iter->key == iter_begin->key)) {
				iter++;
				count++;
			}
			entry = add_jump_label_entry(iter_begin->key,
							count, iter_begin);
			if (IS_ERR(entry))
				return PTR_ERR(entry);
		 } else {
			WARN_ONCE(1, KERN_ERR "build_jump_hashtable: unexpected entry!\n");
			return -1;
		}
	}
	return 0;
}

/***
 * jump_label_update - update jump label text
 * @key -  key value associated with a a jump label
 * @type - enum set to JUMP_LABEL_ENABLE or JUMP_LABEL_DISABLE
 *
 * Will enable/disable the jump for jump label @key, depending on the
 * value of @type.
 *
 */

void jump_label_update(unsigned long key, enum jump_label_type type)
{
	struct jump_entry *iter;
	struct jump_label_entry *entry;
	struct hlist_node *module_node;
	struct jump_label_module_entry *e_module;
	int count;

	mutex_lock(&jump_label_mutex);
	entry = get_jump_label_entry((jump_label_t)key);
	if (entry) {
		count = entry->nr_entries;
		iter = entry->table;
		while (count--) {
			if (kernel_text_address(iter->code))
				arch_jump_label_transform(iter, type);
			iter++;
		}
		/* eanble/disable jump labels in modules */
		hlist_for_each_entry(e_module, module_node, &(entry->modules),
							hlist) {
			count = e_module->nr_entries;
			iter = e_module->table;
			while (count--) {
				if (kernel_text_address(iter->code))
					arch_jump_label_transform(iter, type);
				iter++;
			}
		}
	}
	mutex_unlock(&jump_label_mutex);
}

static __init int init_jump_label(void)
{
	int ret;
	struct jump_entry *iter_start = __start___jump_table;
	struct jump_entry *iter_stop = __stop___jump_table;
	struct jump_entry *iter;

	mutex_lock(&jump_label_mutex);
	ret = build_jump_label_hashtable(__start___jump_table,
					 __stop___jump_table);
	iter = iter_start;
	while (iter < iter_stop) {
		arch_jump_label_text_poke_early(iter->code);
		iter++;
	}
	mutex_unlock(&jump_label_mutex);
	return ret;
}
early_initcall(init_jump_label);

#ifdef CONFIG_MODULES

static struct jump_label_module_entry *
add_jump_label_module_entry(struct jump_label_entry *entry,
			    struct jump_entry *iter_begin,
			    int count, struct module *mod)
{
	struct jump_label_module_entry *e;

	e = kmalloc(sizeof(struct jump_label_module_entry), GFP_KERNEL);
	if (!e)
		return ERR_PTR(-ENOMEM);
	e->mod = mod;
	e->nr_entries = count;
	e->table = iter_begin;
	hlist_add_head(&e->hlist, &entry->modules);
	return e;
}

static int add_jump_label_module(struct module *mod)
{
	struct jump_entry *iter, *iter_begin;
	struct jump_label_entry *entry;
	struct jump_label_module_entry *module_entry;
	int count;

	/* if the module doesn't have jump label entries, just return */
	if (!mod->num_jump_entries)
		return 0;

	sort_jump_label_entries(mod->jump_entries,
				mod->jump_entries + mod->num_jump_entries);
	iter = mod->jump_entries;
	while (iter < mod->jump_entries + mod->num_jump_entries) {
		entry = get_jump_label_entry(iter->key);
		iter_begin = iter;
		count = 0;
		while ((iter < mod->jump_entries + mod->num_jump_entries) &&
			(iter->key == iter_begin->key)) {
				iter++;
				count++;
		}
		if (!entry) {
			entry = add_jump_label_entry(iter_begin->key, 0, NULL);
			if (IS_ERR(entry))
				return PTR_ERR(entry);
		}
		module_entry = add_jump_label_module_entry(entry, iter_begin,
							   count, mod);
		if (IS_ERR(module_entry))
			return PTR_ERR(module_entry);
	}
	return 0;
}

static void remove_jump_label_module(struct module *mod)
{
	struct hlist_head *head;
	struct hlist_node *node, *node_next, *module_node, *module_node_next;
	struct jump_label_entry *e;
	struct jump_label_module_entry *e_module;
	int i;

	/* if the module doesn't have jump label entries, just return */
	if (!mod->num_jump_entries)
		return;

	for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
		head = &jump_label_table[i];
		hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
			hlist_for_each_entry_safe(e_module, module_node,
						  module_node_next,
						  &(e->modules), hlist) {
				if (e_module->mod == mod) {
					hlist_del(&e_module->hlist);
					kfree(e_module);
				}
			}
			if (hlist_empty(&e->modules) && (e->nr_entries == 0)) {
				hlist_del(&e->hlist);
				kfree(e);
			}
		}
	}
}

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:
		mutex_lock(&jump_label_mutex);
		ret = add_jump_label_module(mod);
		if (ret)
			remove_jump_label_module(mod);
		mutex_unlock(&jump_label_mutex);
		break;
	case MODULE_STATE_GOING:
		mutex_lock(&jump_label_mutex);
		remove_jump_label_module(mod);
		mutex_unlock(&jump_label_mutex);
		break;
	}
	return ret;
}

/***
 * 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;

	/* if the module doesn't have jump label entries, just return */
	if (!mod->num_jump_entries)
		return;

	iter = mod->jump_entries;
	while (iter < mod->jump_entries + mod->num_jump_entries) {
		arch_jump_label_text_poke_early(iter->code);
		iter++;
	}
}

struct notifier_block jump_label_module_nb = {
	.notifier_call = jump_label_module_notify,
	.priority = 0,
};

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

#endif /* CONFIG_MODULES */

#endif
Commit	Line	Data
bf5438fc JB	1	/*
	2	* jump label support
	3	*
	4	* Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
	5	*
	6	*/
	7	#include <linux/jump_label.h>
	8	#include <linux/memory.h>
	9	#include <linux/uaccess.h>
	10	#include <linux/module.h>
	11	#include <linux/list.h>
	12	#include <linux/jhash.h>
	13	#include <linux/slab.h>
	14	#include <linux/sort.h>
	15	#include <linux/err.h>
	16
	17	#ifdef HAVE_JUMP_LABEL
	18
	19	#define JUMP_LABEL_HASH_BITS 6
	20	#define JUMP_LABEL_TABLE_SIZE (1 << JUMP_LABEL_HASH_BITS)
	21	static struct hlist_head jump_label_table[JUMP_LABEL_TABLE_SIZE];
	22
	23	/* mutex to protect coming/going of the the jump_label table */
	24	static DEFINE_MUTEX(jump_label_mutex);
	25
	26	struct jump_label_entry {
	27	struct hlist_node hlist;
	28	struct jump_entry *table;
	29	int nr_entries;
	30	/* hang modules off here */
	31	struct hlist_head modules;
	32	unsigned long key;
	33	};
	34
	35	struct jump_label_module_entry {
	36	struct hlist_node hlist;
	37	struct jump_entry *table;
	38	int nr_entries;
	39	struct module *mod;
	40	};
	41
	42	static int jump_label_cmp(const void a, const void b)
	43	{
	44	const struct jump_entry *jea = a;
	45	const struct jump_entry *jeb = b;
	46
	47	if (jea->key < jeb->key)
	48	return -1;
	49
	50	if (jea->key > jeb->key)
	51	return 1;
	52
	53	return 0;
	54	}
	55
	56	static void
	57	sort_jump_label_entries(struct jump_entry start, struct jump_entry stop)
	58	{
	59	unsigned long size;
	60
	61	size = (((unsigned long)stop - (unsigned long)start)
	62	/ sizeof(struct jump_entry));
	63	sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
	64	}
65
66	static struct jump_label_entry *get_jump_label_entry(jump_label_t key)
67	{
68	struct hlist_head *head;
69	struct hlist_node *node;
70	struct jump_label_entry *e;
71	u32 hash = jhash((void *)&key, sizeof(jump_label_t), 0);
72
73	head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
74	hlist_for_each_entry(e, node, head, hlist) {
75	if (key == e->key)
76	return e;
77	}
78	return NULL;
79	}
80
81	static struct jump_label_entry *
82	add_jump_label_entry(jump_label_t key, int nr_entries, struct jump_entry *table)
83	{
84	struct hlist_head *head;
85	struct jump_label_entry *e;
86	u32 hash;
87
88	e = get_jump_label_entry(key);
89	if (e)
90	return ERR_PTR(-EEXIST);
91
92	e = kmalloc(sizeof(struct jump_label_entry), GFP_KERNEL);
93	if (!e)
94	return ERR_PTR(-ENOMEM);
95
96	hash = jhash((void *)&key, sizeof(jump_label_t), 0);
97	head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
98	e->key = key;
99	e->table = table;
100	e->nr_entries = nr_entries;
101	INIT_HLIST_HEAD(&(e->modules));
102	hlist_add_head(&e->hlist, head);
103	return e;
104	}
105
106	static int
107	build_jump_label_hashtable(struct jump_entry start, struct jump_entry stop)
108	{
109	struct jump_entry iter, iter_begin;
110	struct jump_label_entry *entry;
111	int count;
112
113	sort_jump_label_entries(start, stop);
114	iter = start;
115	while (iter < stop) {
116	entry = get_jump_label_entry(iter->key);
117	if (!entry) {
118	iter_begin = iter;
119	count = 0;
120	while ((iter < stop) &&
121	(iter->key == iter_begin->key)) {
122	iter++;
123	count++;
124	}
125	entry = add_jump_label_entry(iter_begin->key,
126	count, iter_begin);
127	if (IS_ERR(entry))
128	return PTR_ERR(entry);
129	} else {
130	WARN_ONCE(1, KERN_ERR "build_jump_hashtable: unexpected entry!\n");
131	return -1;
132	}
133	}
134	return 0;
135	}
136
137	/***
138	* jump_label_update - update jump label text
139	* @key - key value associated with a a jump label
140	* @type - enum set to JUMP_LABEL_ENABLE or JUMP_LABEL_DISABLE
141	*
142	* Will enable/disable the jump for jump label @key, depending on the
143	* value of @type.
144	*
145	*/
146
147	void jump_label_update(unsigned long key, enum jump_label_type type)
148	{
149	struct jump_entry *iter;
150	struct jump_label_entry *entry;
151	struct hlist_node *module_node;
152	struct jump_label_module_entry *e_module;
153	int count;
154
155	mutex_lock(&jump_label_mutex);
156	entry = get_jump_label_entry((jump_label_t)key);
157	if (entry) {
158	count = entry->nr_entries;
159	iter = entry->table;
160	while (count--) {
161	if (kernel_text_address(iter->code))
162	arch_jump_label_transform(iter, type);
163	iter++;
164	}
165	/* eanble/disable jump labels in modules */
166	hlist_for_each_entry(e_module, module_node, &(entry->modules),
167	hlist) {
168	count = e_module->nr_entries;
169	iter = e_module->table;
170	while (count--) {
171	if (kernel_text_address(iter->code))
172	arch_jump_label_transform(iter, type);
173	iter++;
174	}
175	}
176	}
177	mutex_unlock(&jump_label_mutex);
178	}
179
180	static __init int init_jump_label(void)
181	{
182	int ret;
183	struct jump_entry *iter_start = __start___jump_table;
184	struct jump_entry *iter_stop = __stop___jump_table;
185	struct jump_entry *iter;
186
187	mutex_lock(&jump_label_mutex);
188	ret = build_jump_label_hashtable(__start___jump_table,
189	__stop___jump_table);
190	iter = iter_start;
191	while (iter < iter_stop) {
192	arch_jump_label_text_poke_early(iter->code);
193	iter++;
194	}
195	mutex_unlock(&jump_label_mutex);
196	return ret;
197	}
198	early_initcall(init_jump_label);
199
200	#ifdef CONFIG_MODULES
201
202	static struct jump_label_module_entry *
203	add_jump_label_module_entry(struct jump_label_entry *entry,
204	struct jump_entry *iter_begin,
205	int count, struct module *mod)
206	{
207	struct jump_label_module_entry *e;
208
209	e = kmalloc(sizeof(struct jump_label_module_entry), GFP_KERNEL);
210	if (!e)
211	return ERR_PTR(-ENOMEM);
212	e->mod = mod;
213	e->nr_entries = count;
214	e->table = iter_begin;
215	hlist_add_head(&e->hlist, &entry->modules);
216	return e;
217	}
218
219	static int add_jump_label_module(struct module *mod)
220	{
221	struct jump_entry iter, iter_begin;
222	struct jump_label_entry *entry;
223	struct jump_label_module_entry *module_entry;
224	int count;
225
226	/* if the module doesn't have jump label entries, just return */
227	if (!mod->num_jump_entries)
228	return 0;
229
230	sort_jump_label_entries(mod->jump_entries,
231	mod->jump_entries + mod->num_jump_entries);
232	iter = mod->jump_entries;
233	while (iter < mod->jump_entries + mod->num_jump_entries) {
234	entry = get_jump_label_entry(iter->key);
235	iter_begin = iter;
236	count = 0;
237	while ((iter < mod->jump_entries + mod->num_jump_entries) &&
238	(iter->key == iter_begin->key)) {
239	iter++;
240	count++;
241	}
242	if (!entry) {
243	entry = add_jump_label_entry(iter_begin->key, 0, NULL);
244	if (IS_ERR(entry))
245	return PTR_ERR(entry);
246	}
247	module_entry = add_jump_label_module_entry(entry, iter_begin,
248	count, mod);
249	if (IS_ERR(module_entry))
250	return PTR_ERR(module_entry);
251	}
252	return 0;
253	}
254
255	static void remove_jump_label_module(struct module *mod)
256	{
257	struct hlist_head *head;
258	struct hlist_node node, node_next, module_node, module_node_next;
259	struct jump_label_entry *e;
260	struct jump_label_module_entry *e_module;
261	int i;
262
263	/* if the module doesn't have jump label entries, just return */
264	if (!mod->num_jump_entries)
265	return;
266
267	for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
268	head = &jump_label_table[i];
269	hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
270	hlist_for_each_entry_safe(e_module, module_node,
271	module_node_next,
272	&(e->modules), hlist) {
273	if (e_module->mod == mod) {
274	hlist_del(&e_module->hlist);
275	kfree(e_module);
276	}
277	}
278	if (hlist_empty(&e->modules) && (e->nr_entries == 0)) {
279	hlist_del(&e->hlist);
280	kfree(e);
281	}
282	}
283	}
284	}
285
286	static int
287	jump_label_module_notify(struct notifier_block *self, unsigned long val,
288	void *data)
289	{
290	struct module *mod = data;
291	int ret = 0;
292
293	switch (val) {
294	case MODULE_STATE_COMING:
295	mutex_lock(&jump_label_mutex);
296	ret = add_jump_label_module(mod);
297	if (ret)
298	remove_jump_label_module(mod);
299	mutex_unlock(&jump_label_mutex);
300	break;
301	case MODULE_STATE_GOING:
302	mutex_lock(&jump_label_mutex);
303	remove_jump_label_module(mod);
304	mutex_unlock(&jump_label_mutex);
305	break;
306	}
307	return ret;
308	}
309
310	/***
311	* apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
312	* @mod: module to patch
313	*
314	* Allow for run-time selection of the optimal nops. Before the module
315	* loads patch these with arch_get_jump_label_nop(), which is specified by
316	* the arch specific jump label code.
317	*/
318	void jump_label_apply_nops(struct module *mod)
319	{
320	struct jump_entry *iter;
321
322	/* if the module doesn't have jump label entries, just return */
323	if (!mod->num_jump_entries)
324	return;
325
326	iter = mod->jump_entries;
327	while (iter < mod->jump_entries + mod->num_jump_entries) {
328	arch_jump_label_text_poke_early(iter->code);
329	iter++;
330	}
331	}
332
333	struct notifier_block jump_label_module_nb = {
334	.notifier_call = jump_label_module_notify,
335	.priority = 0,
336	};
337
338	static __init int init_jump_label_module(void)
339	{
340	return register_module_notifier(&jump_label_module_nb);
341	}
342	early_initcall(init_jump_label_module);
343
344	#endif /* CONFIG_MODULES */
345
346	#endif