1 files changed, 222 insertions, 84 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 53042f118f2..cbf8b09f63a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -47,12 +47,12 @@
 int ftrace_enabled __read_mostly;
 static int last_ftrace_enabled;
 
+/* ftrace_pid_trace >= 0 will only trace threads with this pid */
+static int ftrace_pid_trace = -1;
+
 /* Quick disabling of function tracer. */
 int function_trace_stop;
 
-/* By default, current tracing type is normal tracing. */
-enum ftrace_tracing_type_t ftrace_tracing_type = FTRACE_TYPE_ENTER;
-
 /*
  * ftrace_disabled is set when an anomaly is discovered.
  * ftrace_disabled is much stronger than ftrace_enabled.
@@ -61,6 +61,7 @@ static int ftrace_disabled __read_mostly;
 
 static DEFINE_SPINLOCK(ftrace_lock);
 static DEFINE_MUTEX(ftrace_sysctl_lock);
+static DEFINE_MUTEX(ftrace_start_lock);
 
 static struct ftrace_ops ftrace_list_end __read_mostly =
 {
@@ -70,6 +71,7 @@ static struct ftrace_ops ftrace_list_end __read_mostly =
 static struct ftrace_ops *ftrace_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 void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
 {
@@ -86,6 +88,21 @@ static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
 	};
 }
 
+static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
+{
+	if (current->pid != ftrace_pid_trace)
+		return;
+
+	ftrace_pid_function(ip, parent_ip);
+}
+
+static void set_ftrace_pid_function(ftrace_func_t func)
+{
+	/* do not set ftrace_pid_function to itself! */
+	if (func != ftrace_pid_func)
+		ftrace_pid_function = func;
+}
+
 /**
  * clear_ftrace_function - reset the ftrace function
  *
@@ -96,6 +113,7 @@ void clear_ftrace_function(void)
 {
 	ftrace_trace_function = ftrace_stub;
 	__ftrace_trace_function = ftrace_stub;
+	ftrace_pid_function = ftrace_stub;
 }
 
 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
@@ -128,20 +146,26 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
 	ftrace_list = ops;
 
 	if (ftrace_enabled) {
+		ftrace_func_t func;
+
+		if (ops->next == &ftrace_list_end)
+			func = ops->func;
+		else
+			func = ftrace_list_func;
+
+		if (ftrace_pid_trace >= 0) {
+			set_ftrace_pid_function(func);
+			func = ftrace_pid_func;
+		}
+
 		/*
 		 * For one func, simply call it directly.
 		 * For more than one func, call the chain.
 		 */
 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
-		if (ops->next == &ftrace_list_end)
-			ftrace_trace_function = ops->func;
-		else
-			ftrace_trace_function = ftrace_list_func;
+		ftrace_trace_function = func;
 #else
-		if (ops->next == &ftrace_list_end)
-			__ftrace_trace_function = ops->func;
-		else
-			__ftrace_trace_function = ftrace_list_func;
+		__ftrace_trace_function = func;
 		ftrace_trace_function = ftrace_test_stop_func;
 #endif
 	}
@@ -182,8 +206,19 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 
 	if (ftrace_enabled) {
 		/* If we only have one func left, then call that directly */
-		if (ftrace_list->next == &ftrace_list_end)
-			ftrace_trace_function = ftrace_list->func;
+		if (ftrace_list->next == &ftrace_list_end) {
+			ftrace_func_t func = ftrace_list->func;
+
+			if (ftrace_pid_trace >= 0) {
+				set_ftrace_pid_function(func);
+				func = ftrace_pid_func;
+			}
+#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+			ftrace_trace_function = func;
+#else
+			__ftrace_trace_function = func;
+#endif
+		}
 	}
 
  out:
@@ -192,6 +227,38 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 	return ret;
 }
 
+static void ftrace_update_pid_func(void)
+{
+	ftrace_func_t func;
+
+	/* should not be called from interrupt context */
+	spin_lock(&ftrace_lock);
+
+	if (ftrace_trace_function == ftrace_stub)
+		goto out;
+
+	func = ftrace_trace_function;
+
+	if (ftrace_pid_trace >= 0) {
+		set_ftrace_pid_function(func);
+		func = ftrace_pid_func;
+	} else {
+		if (func != ftrace_pid_func)
+			goto out;
+
+		set_ftrace_pid_function(func);
+	}
+
+#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+	ftrace_trace_function = func;
+#else
+	__ftrace_trace_function = func;
+#endif
+
+ out:
+	spin_unlock(&ftrace_lock);
+}
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 # error Dynamic ftrace depends on MCOUNT_RECORD
@@ -211,6 +278,8 @@ enum {
 	FTRACE_UPDATE_TRACE_FUNC	= (1 << 2),
 	FTRACE_ENABLE_MCOUNT		= (1 << 3),
 	FTRACE_DISABLE_MCOUNT		= (1 << 4),
+	FTRACE_START_FUNC_RET		= (1 << 5),
+	FTRACE_STOP_FUNC_RET		= (1 << 6),
 };
 
 static int ftrace_filtered;
@@ -395,14 +464,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 	unsigned long ip, fl;
 	unsigned long ftrace_addr;
 
-#ifdef CONFIG_FUNCTION_RET_TRACER
-	if (ftrace_tracing_type == FTRACE_TYPE_ENTER)
-		ftrace_addr = (unsigned long)ftrace_caller;
-	else
-		ftrace_addr = (unsigned long)ftrace_return_caller;
-#else
 	ftrace_addr = (unsigned long)ftrace_caller;
-#endif
 
 	ip = rec->ip;
 
@@ -535,6 +597,11 @@ static int __ftrace_modify_code(void *data)
 	if (*command & FTRACE_UPDATE_TRACE_FUNC)
 		ftrace_update_ftrace_func(ftrace_trace_function);
 
+	if (*command & FTRACE_START_FUNC_RET)
+		ftrace_enable_ftrace_graph_caller();
+	else if (*command & FTRACE_STOP_FUNC_RET)
+		ftrace_disable_ftrace_graph_caller();
+
 	return 0;
 }
 
@@ -545,12 +612,22 @@ static void ftrace_run_update_code(int command)
 
 static ftrace_func_t saved_ftrace_func;
 static int ftrace_start_up;
-static DEFINE_MUTEX(ftrace_start_lock);
 
-static void ftrace_startup(void)
+static void ftrace_startup_enable(int command)
 {
-	int command = 0;
+	if (saved_ftrace_func != ftrace_trace_function) {
+		saved_ftrace_func = ftrace_trace_function;
+		command |= FTRACE_UPDATE_TRACE_FUNC;
+	}
+
+	if (!command || !ftrace_enabled)
+		return;
+
+	ftrace_run_update_code(command);
+}
 
+static void ftrace_startup(int command)
+{
 	if (unlikely(ftrace_disabled))
 		return;
 
@@ -558,23 +635,13 @@ static void ftrace_startup(void)
 	ftrace_start_up++;
 	command |= FTRACE_ENABLE_CALLS;
 
-	if (saved_ftrace_func != ftrace_trace_function) {
-		saved_ftrace_func = ftrace_trace_function;
-		command |= FTRACE_UPDATE_TRACE_FUNC;
-	}
+	ftrace_startup_enable(command);
 
-	if (!command || !ftrace_enabled)
-		goto out;
-
-	ftrace_run_update_code(command);
- out:
 	mutex_unlock(&ftrace_start_lock);
 }
 
-static void ftrace_shutdown(void)
+static void ftrace_shutdown(int command)
 {
-	int command = 0;
-
 	if (unlikely(ftrace_disabled))
 		return;
 
@@ -1262,13 +1329,10 @@ static struct file_operations ftrace_notrace_fops = {
 	.release = ftrace_notrace_release,
 };
 
-static __init int ftrace_init_debugfs(void)
+static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
 {
-	struct dentry *d_tracer;
 	struct dentry *entry;
 
-	d_tracer = tracing_init_dentry();
-
 	entry = debugfs_create_file("available_filter_functions", 0444,
 				    d_tracer, NULL, &ftrace_avail_fops);
 	if (!entry)
@@ -1295,8 +1359,6 @@ static __init int ftrace_init_debugfs(void)
 	return 0;
 }
 
-fs_initcall(ftrace_init_debugfs);
-
 static int ftrace_convert_nops(struct module *mod,
 			       unsigned long *start,
 			       unsigned long *end)
@@ -1382,12 +1444,101 @@ static int __init ftrace_nodyn_init(void)
 }
 device_initcall(ftrace_nodyn_init);
 
-# define ftrace_startup()		do { } while (0)
-# define ftrace_shutdown()		do { } while (0)
+static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
+static inline void ftrace_startup_enable(int command) { }
+/* Keep as macros so we do not need to define the commands */
+# define ftrace_startup(command)	do { } while (0)
+# define ftrace_shutdown(command)	do { } while (0)
 # define ftrace_startup_sysctl()	do { } while (0)
 # define ftrace_shutdown_sysctl()	do { } while (0)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+static ssize_t
+ftrace_pid_read(struct file *file, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	int r;
+
+	if (ftrace_pid_trace >= 0)
+		r = sprintf(buf, "%u\n", ftrace_pid_trace);
+	else
+		r = sprintf(buf, "no pid\n");
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+ftrace_pid_write(struct file *filp, const char __user *ubuf,
+		   size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	long val;
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = strict_strtol(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&ftrace_start_lock);
+	if (ret < 0) {
+		/* disable pid tracing */
+		if (ftrace_pid_trace < 0)
+			goto out;
+		ftrace_pid_trace = -1;
+
+	} else {
+
+		if (ftrace_pid_trace == val)
+			goto out;
+
+		ftrace_pid_trace = val;
+	}
+
+	/* update the function call */
+	ftrace_update_pid_func();
+	ftrace_startup_enable(0);
+
+ out:
+	mutex_unlock(&ftrace_start_lock);
+
+	return cnt;
+}
+
+static struct file_operations ftrace_pid_fops = {
+	.read = ftrace_pid_read,
+	.write = ftrace_pid_write,
+};
+
+static __init int ftrace_init_debugfs(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
+	d_tracer = tracing_init_dentry();
+	if (!d_tracer)
+		return 0;
+
+	ftrace_init_dyn_debugfs(d_tracer);
+
+	entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
+				    NULL, &ftrace_pid_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'set_ftrace_pid' entry\n");
+	return 0;
+}
+
+fs_initcall(ftrace_init_debugfs);
+
 /**
  * ftrace_kill - kill ftrace
  *
@@ -1422,15 +1573,9 @@ int register_ftrace_function(struct ftrace_ops *ops)
 
 	mutex_lock(&ftrace_sysctl_lock);
 
-	if (ftrace_tracing_type == FTRACE_TYPE_RETURN) {
-		ret = -EBUSY;
-		goto out;
-	}
-
 	ret = __register_ftrace_function(ops);
-	ftrace_startup();
+	ftrace_startup(0);
 
-out:
 	mutex_unlock(&ftrace_sysctl_lock);
 	return ret;
 }
@@ -1447,7 +1592,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops)
 
 	mutex_lock(&ftrace_sysctl_lock);
 	ret = __unregister_ftrace_function(ops);
-	ftrace_shutdown();
+	ftrace_shutdown(0);
 	mutex_unlock(&ftrace_sysctl_lock);
 
 	return ret;
@@ -1496,14 +1641,15 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 	return ret;
 }
 
-#ifdef CONFIG_FUNCTION_RET_TRACER
-
-static atomic_t ftrace_retfunc_active;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
-/* The callback that hooks the return of a function */
-trace_function_return_t ftrace_function_return =
-			(trace_function_return_t)ftrace_stub;
+static atomic_t ftrace_graph_active;
 
+/* The callbacks that hook a function */
+trace_func_graph_ret_t ftrace_graph_return =
+			(trace_func_graph_ret_t)ftrace_stub;
+trace_func_graph_ent_t ftrace_graph_entry =
+			(trace_func_graph_ent_t)ftrace_stub;
 
 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
@@ -1549,7 +1695,7 @@ free:
 }
 
 /* Allocate a return stack for each task */
-static int start_return_tracing(void)
+static int start_graph_tracing(void)
 {
 	struct ftrace_ret_stack **ret_stack_list;
 	int ret;
@@ -1569,52 +1715,46 @@ static int start_return_tracing(void)
 	return ret;
 }
 
-int register_ftrace_return(trace_function_return_t func)
+int register_ftrace_graph(trace_func_graph_ret_t retfunc,
+			trace_func_graph_ent_t entryfunc)
 {
 	int ret = 0;
 
 	mutex_lock(&ftrace_sysctl_lock);
 
-	/*
-	 * Don't launch return tracing if normal function
-	 * tracing is already running.
-	 */
-	if (ftrace_trace_function != ftrace_stub) {
-		ret = -EBUSY;
-		goto out;
-	}
-	atomic_inc(&ftrace_retfunc_active);
-	ret = start_return_tracing();
+	atomic_inc(&ftrace_graph_active);
+	ret = start_graph_tracing();
 	if (ret) {
-		atomic_dec(&ftrace_retfunc_active);
+		atomic_dec(&ftrace_graph_active);
 		goto out;
 	}
-	ftrace_tracing_type = FTRACE_TYPE_RETURN;
-	ftrace_function_return = func;
-	ftrace_startup();
+
+	ftrace_graph_return = retfunc;
+	ftrace_graph_entry = entryfunc;
+
+	ftrace_startup(FTRACE_START_FUNC_RET);
 
 out:
 	mutex_unlock(&ftrace_sysctl_lock);
 	return ret;
 }
 
-void unregister_ftrace_return(void)
+void unregister_ftrace_graph(void)
 {
 	mutex_lock(&ftrace_sysctl_lock);
 
-	atomic_dec(&ftrace_retfunc_active);
-	ftrace_function_return = (trace_function_return_t)ftrace_stub;
-	ftrace_shutdown();
-	/* Restore normal tracing type */
-	ftrace_tracing_type = FTRACE_TYPE_ENTER;
+	atomic_dec(&ftrace_graph_active);
+	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
+	ftrace_graph_entry = (trace_func_graph_ent_t)ftrace_stub;
+	ftrace_shutdown(FTRACE_STOP_FUNC_RET);
 
 	mutex_unlock(&ftrace_sysctl_lock);
 }
 
 /* Allocate a return stack for newly created task */
-void ftrace_retfunc_init_task(struct task_struct *t)
+void ftrace_graph_init_task(struct task_struct *t)
 {
-	if (atomic_read(&ftrace_retfunc_active)) {
+	if (atomic_read(&ftrace_graph_active)) {
 		t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
 				* sizeof(struct ftrace_ret_stack),
 				GFP_KERNEL);
@@ -1626,7 +1766,7 @@ void ftrace_retfunc_init_task(struct task_struct *t)
 		t->ret_stack = NULL;
 }
 
-void ftrace_retfunc_exit_task(struct task_struct *t)
+void ftrace_graph_exit_task(struct task_struct *t)
 {
 	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
 
@@ -1638,5 +1778,3 @@ void ftrace_retfunc_exit_task(struct task_struct *t)
 }
 #endif
 
-
-