path: root/kernel/trace/trace_functions_graph.c

/*
 *
 * Function graph tracer.
 * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
 * Mostly borrowed from function tracer which
 * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
 *
 */
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/fs.h>

#include "trace.h"
#include "trace_output.h"

static bool kill_ftrace_graph;

/**
 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
 *
 * ftrace_graph_stop() is called when a severe error is detected in
 * the function graph tracing. This function is called by the critical
 * paths of function graph to keep those paths from doing any more harm.
 */
bool ftrace_graph_is_dead(void)
{
	return kill_ftrace_graph;
}

/**
 * ftrace_graph_stop - set to permanently disable function graph tracincg
 *
 * In case of an error int function graph tracing, this is called
 * to try to keep function graph tracing from causing any more harm.
 * Usually this is pretty severe and this is called to try to at least
 * get a warning out to the user.
 */
void ftrace_graph_stop(void)
{
	kill_ftrace_graph = true;
}

/* When set, irq functions will be ignored */
static int ftrace_graph_skip_irqs;

struct fgraph_cpu_data {
	pid_t		last_pid;
	int		depth;
	int		depth_irq;
	int		ignore;
	unsigned long	enter_funcs[FTRACE_RETFUNC_DEPTH];
};

struct fgraph_data {
	struct fgraph_cpu_data __percpu *cpu_data;

	/* Place to preserve last processed entry. */
	struct ftrace_graph_ent_entry	ent;
	struct ftrace_graph_ret_entry	ret;
	int				failed;
	int				cpu;
};

#define TRACE_GRAPH_INDENT	2

static unsigned int max_depth;

static struct