1 files changed, 155 insertions, 38 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 92b6fdf49ae..6c7e1df39b5 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -87,24 +87,29 @@ static struct ftrace_ops ftrace_list_end __read_mostly =
 	.func		= ftrace_stub,
 };
 
-static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
+static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
+static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
 static struct ftrace_ops global_ops;
 
+static void
+ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
+
 /*
- * Traverse the ftrace_list, invoking all entries.  The reason that we
+ * Traverse the ftrace_global_list, invoking all entries.  The reason that we
  * can use rcu_dereference_raw() is that elements removed from this list
  * are simply leaked, so there is no need to interact with a grace-period
  * mechanism.  The rcu_dereference_raw() calls are needed to handle
- * concurrent insertions into the ftrace_list.
+ * concurrent insertions into the ftrace_global_list.
  *
  * Silly Alpha and silly pointer-speculation compiler optimizations!
  */
-static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
+static void ftrace_global_list_func(unsigned long ip,
+				    unsigned long parent_ip)
 {
-	struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
+	struct ftrace_ops *op = rcu_dereference_raw(ftrace_global_list); /*see above*/
 
 	while (op != &ftrace_list_end) {
 		op->func(ip, parent_ip);
@@ -163,11 +168,11 @@ static void update_global_ops(void)
 	 * function directly. Otherwise, we need to iterate over the
 	 * registered callers.
 	 */
-	if (ftrace_list == &ftrace_list_end ||
-	    ftrace_list->next == &ftrace_list_end)
-		func = ftrace_list->func;
+	if (ftrace_global_list == &ftrace_list_end ||
+	    ftrace_global_list->next == &ftrace_list_end)
+		func = ftrace_global_list->func;
 	else
-		func = ftrace_list_func;
+		func = ftrace_global_list_func;
 
 	/* If we filter on pids, update to use the pid function */
 	if (!list_empty(&ftrace_pids)) {
@@ -184,7 +189,11 @@ static void update_ftrace_function(void)
 
 	update_global_ops();
 
-	func = global_ops.func;
+	if (ftrace_ops_list == &ftrace_list_end ||
+	    ftrace_ops_list->next == &ftrace_list_end)
+		func = ftrace_ops_list->func;
+	else
+		func = ftrace_ops_list_func;
 
 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	ftrace_trace_function = func;
@@ -198,10 +207,10 @@ static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 {
 	ops->next = *list;
 	/*
-	 * We are entering ops into the ftrace_list but another
+	 * We are entering ops into the list but another
 	 * CPU might be walking that list. We need to make sure
 	 * the ops->next pointer is valid before another CPU sees
-	 * the ops pointer included into the ftrace_list.
+	 * the ops pointer included into the list.
 	 */
 	rcu_assign_pointer(*list, ops);
 }
@@ -238,7 +247,18 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
 	if (FTRACE_WARN_ON(ops == &global_ops))
 		return -EINVAL;
 
-	add_ftrace_ops(&ftrace_list, ops);
+	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return -EBUSY;
+
+	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+		int first = ftrace_global_list == &ftrace_list_end;
+		add_ftrace_ops(&ftrace_global_list, ops);
+		ops->flags |= FTRACE_OPS_FL_ENABLED;
+		if (first)
+			add_ftrace_ops(&ftrace_ops_list, &global_ops);
+	} else
+		add_ftrace_ops(&ftrace_ops_list, ops);
+
 	if (ftrace_enabled)
 		update_ftrace_function();
 
@@ -252,12 +272,24 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 	if (ftrace_disabled)
 		return -ENODEV;
 
+	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
+		return -EBUSY;
+
 	if (FTRACE_WARN_ON(ops == &global_ops))
 		return -EINVAL;
 
-	ret = remove_ftrace_ops(&ftrace_list, ops);
+	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+		ret = remove_ftrace_ops(&ftrace_global_list, ops);
+		if (!ret && ftrace_global_list == &ftrace_list_end)
+			ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
+		if (!ret)
+			ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+	} else
+		ret = remove_ftrace_ops(&ftrace_ops_list, ops);
+
 	if (ret < 0)
 		return ret;
+
 	if (ftrace_enabled)
 		update_ftrace_function();
 
@@ -928,10 +960,6 @@ static const struct ftrace_hash empty_hash = {
 };
 #define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
 
-enum {
-	FTRACE_OPS_FL_ENABLED		= 1,
-};
-
 static struct ftrace_ops global_ops = {
 	.func			= ftrace_stub,
 	.notrace_hash		= EMPTY_HASH,
@@ -1190,6 +1218,40 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
 }
 
 /*
+ * Test the hashes for this ops to see if we want to call
+ * the ops->func or not.
+ *
+ * It's a match if the ip is in the ops->filter_hash or
+ * the filter_hash does not exist or is empty,
+ *  AND
+ * the ip is not in the ops->notrace_hash.
+ */
+static int
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+{
+	struct ftrace_hash *filter_hash;
+	struct ftrace_hash *notrace_hash;
+	int ret;
+
+	/* The hashes are freed with call_rcu_sched() */
+	preempt_disable_notrace();
+
+	filter_hash = rcu_dereference_raw(ops->filter_hash);
+	notrace_hash = rcu_dereference_raw(ops->notrace_hash);
+
+	if ((!filter_hash || !filter_hash->count ||
+	     ftrace_lookup_ip(filter_hash, ip)) &&
+	    (!notrace_hash || !notrace_hash->count ||
+	     !ftrace_lookup_ip(notrace_hash, ip)))
+		ret = 1;
+	else
+		ret = 0;
+	preempt_enable_notrace();
+
+	return ret;
+}
+
+/*
  * This is a double for. Do not use 'break' to break out of the loop,
  * you must use a goto.
  */
@@ -1232,7 +1294,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
 	if (filter_hash) {
 		hash = ops->filter_hash;
 		other_hash = ops->notrace_hash;
-		if (!hash->count)
+		if (!hash || !hash->count)
 			all = 1;
 	} else {
 		inc = !inc;
@@ -1242,7 +1304,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
 		 * If the notrace hash has no items,
 		 * then there's nothing to do.
 		 */
-		if (!hash->count)
+		if (hash && !hash->count)
 			return;
 	}
 
@@ -1256,11 +1318,11 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
 			 * Only the filter_hash affects all records.
 			 * Update if the record is not in the notrace hash.
 			 */
-			if (!ftrace_lookup_ip(other_hash, rec->ip))
+			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
 				match = 1;
 		} else {
-			in_hash = !!ftrace_lookup_ip(hash, rec->ip);
-			in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
+			in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
+			in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
 
 			/*
 			 *
@@ -1546,6 +1608,7 @@ static void ftrace_run_update_code(int command)
 
 static ftrace_func_t saved_ftrace_func;
 static int ftrace_start_up;
+static int global_start_up;
 
 static void ftrace_startup_enable(int command)
 {
@@ -1562,14 +1625,25 @@ static void ftrace_startup_enable(int command)
 
 static void ftrace_startup(struct ftrace_ops *ops, int command)
 {
+	bool hash_enable = true;
+
 	if (unlikely(ftrace_disabled))
 		return;
 
 	ftrace_start_up++;
 	command |= FTRACE_ENABLE_CALLS;
 
+	/* ops marked global share the filter hashes */
+	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+		ops = &global_ops;
+		/* Don't update hash if global is already set */
+		if (global_start_up)
+			hash_enable = false;
+		global_start_up++;
+	}
+
 	ops->flags |= FTRACE_OPS_FL_ENABLED;
-	if (ftrace_start_up == 1)
+	if (hash_enable)
 		ftrace_hash_rec_enable(ops, 1);
 
 	ftrace_startup_enable(command);
@@ -1577,6 +1651,8 @@ static void ftrace_startup(struct ftrace_ops *ops, int command)
 
 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
 {
+	bool hash_disable = true;
+
 	if (unlikely(ftrace_disabled))
 		return;
 
@@ -1588,13 +1664,25 @@ static void ftrace_shutdown(struct ftrace_ops *ops, int command)
 	 */
 	WARN_ON_ONCE(ftrace_start_up < 0);
 
-	if (!ftrace_start_up)
+	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+		ops = &global_ops;
+		global_start_up--;
+		WARN_ON_ONCE(global_start_up < 0);
+		/* Don't update hash if global still has users */
+		if (global_start_up) {
+			WARN_ON_ONCE(!ftrace_start_up);
+			hash_disable = false;
+		}
+	}
+
+	if (hash_disable)
 		ftrace_hash_rec_disable(ops, 1);
 
-	if (!ftrace_start_up) {
-		command |= FTRACE_DISABLE_CALLS;
+	if (ops != &global_ops || !global_start_up)
 		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
-	}
+
+	if (!ftrace_start_up)
+		command |= FTRACE_DISABLE_CALLS;
 
 	if (saved_ftrace_func != ftrace_trace_function) {
 		saved_ftrace_func = ftrace_trace_function;
@@ -2381,6 +2469,7 @@ static int ftrace_probe_registered;
 
 static void __enable_ftrace_function_probe(void)
 {
+	int ret;
 	int i;
 
 	if (ftrace_probe_registered)
@@ -2395,13 +2484,16 @@ static void __enable_ftrace_function_probe(void)
 	if (i == FTRACE_FUNC_HASHSIZE)
 		return;
 
-	__register_ftrace_function(&trace_probe_ops);
-	ftrace_startup(&global_ops, 0);
+	ret = __register_ftrace_function(&trace_probe_ops);
+	if (!ret)
+		ftrace_startup(&trace_probe_ops, 0);
+
 	ftrace_probe_registered = 1;
 }
 
 static void __disable_ftrace_function_probe(void)
 {
+	int ret;
 	int i;
 
 	if (!ftrace_probe_registered)
@@ -2414,8 +2506,10 @@ static void __disable_ftrace_function_probe(void)
 	}
 
 	/* no more funcs left */
-	__unregister_ftrace_function(&trace_probe_ops);
-	ftrace_shutdown(&global_ops, 0);
+	ret = __unregister_ftrace_function(&trace_probe_ops);
+	if (!ret)
+		ftrace_shutdown(&trace_probe_ops, 0);
+
 	ftrace_probe_registered = 0;
 }
 
@@ -3319,8 +3413,28 @@ static inline void ftrace_startup_enable(int command) { }
 # define ftrace_shutdown(ops, command)	do { } while (0)
 # define ftrace_startup_sysctl()	do { } while (0)
 # define ftrace_shutdown_sysctl()	do { } while (0)
+
+static inline int
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+{
+	return 1;
+}
+
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+static void
+ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
+{
+	/* see comment above ftrace_global_list_func */
+	struct ftrace_ops *op = rcu_dereference_raw(ftrace_ops_list);
+
+	while (op != &ftrace_list_end) {
+		if (ftrace_ops_test(op, ip))
+			op->func(ip, parent_ip);
+		op = rcu_dereference_raw(op->next);
+	};
+}
+
 static void clear_ftrace_swapper(void)
 {
 	struct task_struct *p;
@@ -3621,7 +3735,9 @@ int register_ftrace_function(struct ftrace_ops *ops)
 		goto out_unlock;
 
 	ret = __register_ftrace_function(ops);
-	ftrace_startup(&global_ops, 0);
+	if (!ret)
+		ftrace_startup(ops, 0);
+
 
  out_unlock:
 	mutex_unlock(&ftrace_lock);
@@ -3640,7 +3756,8 @@ int unregister_ftrace_function(struct ftrace_ops *ops)
 
 	mutex_lock(&ftrace_lock);
 	ret = __unregister_ftrace_function(ops);
-	ftrace_shutdown(&global_ops, 0);
+	if (!ret)
+		ftrace_shutdown(ops, 0);
 	mutex_unlock(&ftrace_lock);
 
 	return ret;
@@ -3670,11 +3787,11 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 		ftrace_startup_sysctl();
 
 		/* we are starting ftrace again */
-		if (ftrace_list != &ftrace_list_end) {
-			if (ftrace_list->next == &ftrace_list_end)
-				ftrace_trace_function = ftrace_list->func;
+		if (ftrace_ops_list != &ftrace_list_end) {
+			if (ftrace_ops_list->next == &ftrace_list_end)
+				ftrace_trace_function = ftrace_ops_list->func;
 			else
-				ftrace_trace_function = ftrace_list_func;
+				ftrace_trace_function = ftrace_ops_list_func;
 		}
 
 	} else {