diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index e08527f5..624a05e 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -33,6 +33,9 @@
 config HAVE_DYNAMIC_FTRACE_WITH_REGS
 	bool
 
+config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	bool
+
 config HAVE_FTRACE_MCOUNT_RECORD
 	bool
 	help
@@ -557,6 +560,11 @@
 	depends on DYNAMIC_FTRACE
 	depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
 
+config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	def_bool y
+	depends on DYNAMIC_FTRACE
+	depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+
 config FUNCTION_PROFILER
 	bool "Kernel function profiler"
 	depends on FUNCTION_TRACER
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b0e7f03..329a3f3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1023,6 +1023,7 @@ static bool update_all_ops;
 struct ftrace_func_entry {
 	struct hlist_node hlist;
 	unsigned long ip;
+	unsigned long direct; /* for direct lookup only */
 };
 
 struct ftrace_func_probe {
@@ -1730,6 +1731,9 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
 			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
 				return false;
 
+			if (ops->flags & FTRACE_OPS_FL_DIRECT)
+				rec->flags |= FTRACE_FL_DIRECT;
+
 			/*
 			 * If there's only a single callback registered to a
 			 * function, and the ops has a trampoline registered
@@ -1758,6 +1762,15 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
 			rec->flags--;
 
 			/*
+			 * Only the internal direct_ops should have the
+			 * DIRECT flag set. Thus, if it is removing a
+			 * function, then that function should no longer
+			 * be direct.
+			 */
+			if (ops->flags & FTRACE_OPS_FL_DIRECT)
+				rec->flags &= ~FTRACE_FL_DIRECT;
+
+			/*
 			 * If the rec had REGS enabled and the ops that is
 			 * being removed had REGS set, then see if there is
 			 * still any ops for this record that wants regs.
@@ -2092,15 +2105,34 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
 	 * If enabling and the REGS flag does not match the REGS_EN, or
 	 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
 	 * this record. Set flags to fail the compare against ENABLED.
+	 * Same for direct calls.
 	 */
 	if (flag) {
-		if (!(rec->flags & FTRACE_FL_REGS) != 
+		if (!(rec->flags & FTRACE_FL_REGS) !=
 		    !(rec->flags & FTRACE_FL_REGS_EN))
 			flag |= FTRACE_FL_REGS;
 
-		if (!(rec->flags & FTRACE_FL_TRAMP) != 
+		if (!(rec->flags & FTRACE_FL_TRAMP) !=
 		    !(rec->flags & FTRACE_FL_TRAMP_EN))
 			flag |= FTRACE_FL_TRAMP;
+
+		/*
+		 * Direct calls are special, as count matters.
+		 * We must test the record for direct, if the
+		 * DIRECT and DIRECT_EN do not match, but only
+		 * if the count is 1. That's because, if the
+		 * count is something other than one, we do not
+		 * want the direct enabled (it will be done via the
+		 * direct helper). But if DIRECT_EN is set, and
+		 * the count is not one, we need to clear it.
+		 */
+		if (ftrace_rec_count(rec) == 1) {
+			if (!(rec->flags & FTRACE_FL_DIRECT) !=
+			    !(rec->flags & FTRACE_FL_DIRECT_EN))
+				flag |= FTRACE_FL_DIRECT;
+		} else if (rec->flags & FTRACE_FL_DIRECT_EN) {
+			flag |= FTRACE_FL_DIRECT;
+		}
 	}
 
 	/* If the state of this record hasn't changed, then do nothing */
@@ -2125,6 +2157,25 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
 				else
 					rec->flags &= ~FTRACE_FL_TRAMP_EN;
 			}
+			if (flag & FTRACE_FL_DIRECT) {
+				/*
+				 * If there's only one user (direct_ops helper)
+				 * then we can call the direct function
+				 * directly (no ftrace trampoline).
+				 */
+				if (ftrace_rec_count(rec) == 1) {
+					if (rec->flags & FTRACE_FL_DIRECT)
+						rec->flags |= FTRACE_FL_DIRECT_EN;
+					else
+						rec->flags &= ~FTRACE_FL_DIRECT_EN;
+				} else {
+					/*
+					 * Can only call directly if there's
+					 * only one callback to the function.
+					 */
+					rec->flags &= ~FTRACE_FL_DIRECT_EN;
+				}
+			}
 		}
 
 		/*
@@ -2154,7 +2205,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
 			 * and REGS states. The _EN flags must be disabled though.
 			 */
 			rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
-					FTRACE_FL_REGS_EN);
+					FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
 	}
 
 	ftrace_bug_type = FTRACE_BUG_NOP;
@@ -2309,6 +2360,51 @@ ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
 	return NULL;
 }
 
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+/* Protected by rcu_tasks for reading, and direct_mutex for writing */
+static struct ftrace_hash *direct_functions = EMPTY_HASH;
+static DEFINE_MUTEX(direct_mutex);
+
+/*
+ * Search the direct_functions hash to see if the given instruction pointer
+ * has a direct caller attached to it.
+ */
+static unsigned long find_rec_direct(unsigned long ip)
+{
+	struct ftrace_func_entry *entry;
+
+	entry = __ftrace_lookup_ip(direct_functions, ip);
+	if (!entry)
+		return 0;
+
+	return entry->direct;
+}
+
+static void call_direct_funcs(unsigned long ip, unsigned long pip,
+			      struct ftrace_ops *ops, struct pt_regs *regs)
+{
+	unsigned long addr;
+
+	addr = find_rec_direct(ip);
+	if (!addr)
+		return;
+
+	arch_ftrace_set_direct_caller(regs, addr);
+}
+
+struct ftrace_ops direct_ops = {
+	.func		= call_direct_funcs,
+	.flags		= FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
+			  | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
+			  | FTRACE_OPS_FL_PERMANENT,
+};
+#else
+static inline unsigned long find_rec_direct(unsigned long ip)
+{
+	return 0;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
 /**
  * ftrace_get_addr_new - Get the call address to set to
  * @rec:  The ftrace record descriptor
@@ -2322,6 +2418,15 @@ ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
 {
 	struct ftrace_ops *ops;
+	unsigned long addr;
+
+	if ((rec->flags & FTRACE_FL_DIRECT) &&
+	    (ftrace_rec_count(rec) == 1)) {
+		addr = find_rec_direct(rec->ip);
+		if (addr)
+			return addr;
+		WARN_ON_ONCE(1);
+	}
 
 	/* Trampolines take precedence over regs */
 	if (rec->flags & FTRACE_FL_TRAMP) {
@@ -2354,6 +2459,15 @@ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
 {
 	struct ftrace_ops *ops;
+	unsigned long addr;
+
+	/* Direct calls take precedence over trampolines */
+	if (rec->flags & FTRACE_FL_DIRECT_EN) {
+		addr = find_rec_direct(rec->ip);
+		if (addr)
+			return addr;
+		WARN_ON_ONCE(1);
+	}
 
 	/* Trampolines take precedence over regs */
 	if (rec->flags & FTRACE_FL_TRAMP_EN) {
@@ -3465,10 +3579,11 @@ static int t_show(struct seq_file *m, void *v)
 	if (iter->flags & FTRACE_ITER_ENABLED) {
 		struct ftrace_ops *ops;
 
-		seq_printf(m, " (%ld)%s%s",
+		seq_printf(m, " (%ld)%s%s%s",
 			   ftrace_rec_count(rec),
 			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
-			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ");
+			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
+			   rec->flags & FTRACE_FL_DIRECT ? " D" : "  ");
 		if (rec->flags & FTRACE_FL_TRAMP_EN) {
 			ops = ftrace_find_tramp_ops_any(rec);
 			if (ops) {
@@ -3484,6 +3599,13 @@ static int t_show(struct seq_file *m, void *v)
 		} else {
 			add_trampoline_func(m, NULL, rec);
 		}
+		if (rec->flags & FTRACE_FL_DIRECT) {
+			unsigned long direct;
+
+			direct = find_rec_direct(rec->ip);
+			if (direct)
+				seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
+		}
 	}	
 
 	seq_putc(m, '\n');
@@ -4815,6 +4937,143 @@ ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
 	return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
 }
 
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+/**
+ * register_ftrace_direct - Call a custom trampoline directly
+ * @ip: The address of the nop at the beginning of a function
+ * @addr: The address of the trampoline to call at @ip
+ *
+ * This is used to connect a direct call from the nop location (@ip)
+ * at the start of ftrace traced functions. The location that it calls
+ * (@addr) must be able to handle a direct call, and save the parameters
+ * of the function being traced, and restore them (or inject new ones
+ * if needed), before returning.
+ *
+ * Returns:
+ *  0 on success
+ *  -EBUSY - Another direct function is already attached (there can be only one)
+ *  -ENODEV - @ip does not point to a ftrace nop location (or not supported)
+ *  -ENOMEM - There was an allocation failure.
+ */
+int register_ftrace_direct(unsigned long ip, unsigned long addr)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *free_hash = NULL;
+	struct dyn_ftrace *rec;
+	int ret = -EBUSY;
+
+	mutex_lock(&direct_mutex);
+
+	/* See if there's a direct function at @ip already */
+	if (find_rec_direct(ip))
+		goto out_unlock;
+
+	ret = -ENODEV;
+	rec = lookup_rec(ip, ip);
+	if (!rec)
+		goto out_unlock;
+
+	/*
+	 * Check if the rec says it has a direct call but we didn't
+	 * find one earlier?
+	 */
+	if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
+		goto out_unlock;
+
+	/* Make sure the ip points to the exact record */
+	ip = rec->ip;
+
+	ret = -ENOMEM;
+	if (ftrace_hash_empty(direct_functions) ||
+	    direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
+		struct ftrace_hash *new_hash;
+		int size = ftrace_hash_empty(direct_functions) ? 0 :
+			direct_functions->count + 1;
+
+		if (size < 32)
+			size = 32;
+
+		new_hash = dup_hash(direct_functions, size);
+		if (!new_hash)
+			goto out_unlock;
+
+		free_hash = direct_functions;
+		direct_functions = new_hash;
+	}
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		goto out_unlock;
+
+	entry->ip = ip;
+	entry->direct = addr;
+	__add_hash_entry(direct_functions, entry);
+
+	ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
+	if (ret)
+		remove_hash_entry(direct_functions, entry);
+
+	if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
+		ret = register_ftrace_function(&direct_ops);
+		if (ret)
+			ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
+	}
+
+	if (ret)
+		kfree(entry);
+ out_unlock:
+	mutex_unlock(&direct_mutex);
+
+	if (free_hash) {
+		synchronize_rcu_tasks();
+		free_ftrace_hash(free_hash);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_ftrace_direct);
+
+int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
+{
+	struct ftrace_func_entry *entry;
+	struct dyn_ftrace *rec;
+	int ret = -ENODEV;
+
+	mutex_lock(&direct_mutex);
+
+	entry = __ftrace_lookup_ip(direct_functions, ip);
+	if (!entry) {
+		/* OK if it is off by a little */
+		rec = lookup_rec(ip, ip);
+		if (!rec || rec->ip == ip)
+			goto out_unlock;
+
+		entry = __ftrace_lookup_ip(direct_functions, rec->ip);
+		if (!entry) {
+			WARN_ON(rec->flags & FTRACE_FL_DIRECT);
+			goto out_unlock;
+		}
+
+		WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
+	}
+
+	if (direct_functions->count == 1)
+		unregister_ftrace_function(&direct_ops);
+
+	ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
+
+	WARN_ON(ret);
+
+	remove_hash_entry(direct_functions, entry);
+
+ out_unlock:
+	mutex_unlock(&direct_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
 /**
  * ftrace_set_filter_ip - set a function to filter on in ftrace by address
  * @ops - the ops to set the filter with