Commit b448c4e3 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
Browse files

ftrace: Replace FTRACE_FL_NOTRACE flag with a hash of ignored functions 



To prepare for the accounting system that will allow multiple users of
the function tracer, having the FTRACE_FL_NOTRACE as a flag in the
dyn_trace record does not make sense.

All ftrace_ops will soon have a hash of functions they should trace
and not trace. By making a global hash of functions not to trace makes
this easier for the transition.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 94692349

include/linux/ftrace.h

+0 −1
Original line number Diff line number Diff line
@@ -149,7 +149,6 @@ enum { 
	FTRACE_FL_FREE		= (1 << 0),

	FTRACE_FL_FILTER	= (1 << 1),

	FTRACE_FL_ENABLED	= (1 << 2),

	FTRACE_FL_NOTRACE	= (1 << 3),

};



struct dyn_ftrace {

kernel/trace/ftrace.c

+150 −26
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ 
/* hash bits for specific function selection */

#define FTRACE_HASH_BITS 7

#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)

#define FTRACE_HASH_MAX_BITS 10



/* ftrace_enabled is a method to turn ftrace on or off */

int ftrace_enabled __read_mostly;
@@ -865,6 +866,22 @@ enum { 
	FTRACE_START_FUNC_RET		= (1 << 3),

	FTRACE_STOP_FUNC_RET		= (1 << 4),

};

struct ftrace_func_entry {

	struct hlist_node hlist;

	unsigned long ip;

};



struct ftrace_hash {

	unsigned long		size_bits;

	struct hlist_head	*buckets;

	unsigned long		count;

};



static struct hlist_head notrace_buckets[1 << FTRACE_HASH_MAX_BITS];

static struct ftrace_hash notrace_hash = {

	.size_bits = FTRACE_HASH_MAX_BITS,

	.buckets = notrace_buckets,

};



static int ftrace_filtered;
@@ -889,6 +906,79 @@ static struct ftrace_page *ftrace_pages; 


static struct dyn_ftrace *ftrace_free_records;



static struct ftrace_func_entry *

ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)

{

	unsigned long key;

	struct ftrace_func_entry *entry;

	struct hlist_head *hhd;

	struct hlist_node *n;



	if (!hash->count)

		return NULL;



	if (hash->size_bits > 0)

		key = hash_long(ip, hash->size_bits);

	else

		key = 0;



	hhd = &hash->buckets[key];



	hlist_for_each_entry_rcu(entry, n, hhd, hlist) {

		if (entry->ip == ip)

			return entry;

	}

	return NULL;

}



static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)

{

	struct ftrace_func_entry *entry;

	struct hlist_head *hhd;

	unsigned long key;



	entry = kmalloc(sizeof(*entry), GFP_KERNEL);

	if (!entry)

		return -ENOMEM;



	if (hash->size_bits)

		key = hash_long(ip, hash->size_bits);

	else

		key = 0;



	entry->ip = ip;

	hhd = &hash->buckets[key];

	hlist_add_head(&entry->hlist, hhd);

	hash->count++;



	return 0;

}



static void

remove_hash_entry(struct ftrace_hash *hash,

		  struct ftrace_func_entry *entry)

{

	hlist_del(&entry->hlist);

	kfree(entry);

	hash->count--;

}



static void ftrace_hash_clear(struct ftrace_hash *hash)

{

	struct hlist_head *hhd;

	struct hlist_node *tp, *tn;

	struct ftrace_func_entry *entry;

	int size = 1 << hash->size_bits;

	int i;



	for (i = 0; i < size; i++) {

		hhd = &hash->buckets[i];

		hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)

			remove_hash_entry(hash, entry);

	}

	FTRACE_WARN_ON(hash->count);

}



/*

 * This is a double for. Do not use 'break' to break out of the loop,

 * you must use a goto.
@@ -1032,7 +1122,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) 
	 * If we want to enable it and filtering is on, enable it only if

	 * it's filtered

	 */

	if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {

	if (enable && !ftrace_lookup_ip(&notrace_hash, rec->ip)) {

		if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))

			flag = FTRACE_FL_ENABLED;

	}
@@ -1465,7 +1555,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos) 
		     !(rec->flags & FTRACE_FL_FILTER)) ||



		    ((iter->flags & FTRACE_ITER_NOTRACE) &&

		     !(rec->flags & FTRACE_FL_NOTRACE))) {

		     !ftrace_lookup_ip(&notrace_hash, rec->ip))) {

			rec = NULL;

			goto retry;

		}
@@ -1609,14 +1699,15 @@ static void ftrace_filter_reset(int enable) 
{

	struct ftrace_page *pg;

	struct dyn_ftrace *rec;

	unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;



	mutex_lock(&ftrace_lock);

	if (enable)

	if (enable) {

		ftrace_filtered = 0;

		do_for_each_ftrace_rec(pg, rec) {

		rec->flags &= ~type;

			rec->flags &= ~FTRACE_FL_FILTER;

		} while_for_each_ftrace_rec();

	} else

		ftrace_hash_clear(&notrace_hash);

	mutex_unlock(&ftrace_lock);

}
@@ -1716,13 +1807,36 @@ static int ftrace_match(char *str, char *regex, int len, int type) 
	return matched;

}



static void

update_record(struct dyn_ftrace *rec, unsigned long flag, int not)

static int

update_record(struct dyn_ftrace *rec, int enable, int not)

{

	struct ftrace_func_entry *entry;

	struct ftrace_hash *hash = &notrace_hash;

	int ret = 0;



	if (enable) {

		if (not)

		rec->flags &= ~flag;

			rec->flags &= ~FTRACE_FL_FILTER;

		else

		rec->flags |= flag;

			rec->flags |= FTRACE_FL_FILTER;

	} else {

		if (not) {

			/* Do nothing if it doesn't exist */

			entry = ftrace_lookup_ip(hash, rec->ip);

			if (!entry)

				return 0;



			remove_hash_entry(hash, entry);

		} else {

			/* Do nothing if it exists */

			entry = ftrace_lookup_ip(hash, rec->ip);

			if (entry)

				return 0;



			ret = add_hash_entry(hash, rec->ip);

		}

	}

	return ret;

}



static int
@@ -1754,16 +1868,14 @@ static int match_records(char *buff, int len, char *mod, int enable, int not) 
	struct dyn_ftrace *rec;

	int type = MATCH_FULL;

	char *search = buff;

	unsigned long flag;

	int found = 0;

	int ret;



	if (len) {

		type = filter_parse_regex(buff, len, &search, &not);

		search_len = strlen(search);

	}



	flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;



	mutex_lock(&ftrace_lock);



	if (unlikely(ftrace_disabled))
@@ -1772,7 +1884,11 @@ static int match_records(char *buff, int len, char *mod, int enable, int not) 
	do_for_each_ftrace_rec(pg, rec) {



		if (ftrace_match_record(rec, mod, search, search_len, type)) {

			update_record(rec, flag, not);

			ret = update_record(rec, enable, not);

			if (ret < 0) {

				found = ret;

				goto out_unlock;

			}

			found = 1;

		}

		/*
@@ -1821,6 +1937,7 @@ static int 
ftrace_mod_callback(char *func, char *cmd, char *param, int enable)

{

	char *mod;

	int ret = -EINVAL;



	/*

	 * cmd == 'mod' because we only registered this func
@@ -1832,15 +1949,19 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable) 


	/* we must have a module name */

	if (!param)

		return -EINVAL;

		return ret;



	mod = strsep(&param, ":");

	if (!strlen(mod))

		return -EINVAL;

		return ret;



	ret = ftrace_match_module_records(func, mod, enable);

	if (!ret)

		ret = -EINVAL;

	if (ret < 0)

		return ret;



	if (ftrace_match_module_records(func, mod, enable))

	return 0;

	return -EINVAL;

}



static struct ftrace_func_command ftrace_mod_cmd = {
@@ -2132,14 +2253,17 @@ static int ftrace_process_regex(char *buff, int len, int enable) 
{

	char *func, *command, *next = buff;

	struct ftrace_func_command *p;

	int ret = -EINVAL;

	int ret;



	func = strsep(&next, ":");



	if (!next) {

		if (ftrace_match_records(func, len, enable))

			return 0;

		ret = ftrace_match_records(func, len, enable);

		if (!ret)

			ret = -EINVAL;

		if (ret < 0)

			return ret;

		return 0;

	}



	/* command found */

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