/*
   *
   * 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/debugfs.h>
  #include <linux/uaccess.h>
  #include <linux/ftrace.h>

  #include <linux/slab.h>

  #include <linux/fs.h>
  
  #include "trace.h"

  #include "trace_output.h"

  /* 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

  /* Flag options */

  #define TRACE_GRAPH_PRINT_OVERRUN	0x1

  #define TRACE_GRAPH_PRINT_CPU		0x2
  #define TRACE_GRAPH_PRINT_OVERHEAD	0x4

  #define TRACE_GRAPH_PRINT_PROC		0x8

  #define TRACE_GRAPH_PRINT_DURATION	0x10

  #define TRACE_GRAPH_PRINT_ABS_TIME	0x20

  #define TRACE_GRAPH_PRINT_IRQS		0x40

  static struct tracer_opt trace_opts[] = {

  	/* Display overruns? (for self-debug purpose) */

  	{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  	/* Display CPU ? */
  	{ TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  	/* Display Overhead ? */
  	{ TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },

  	/* Display proc name/pid */
  	{ TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },

  	/* Display duration of execution */
  	{ TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  	/* Display absolute time of an entry */
  	{ TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },

  	/* Display interrupts */
  	{ TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },

  	{ } /* Empty entry */
  };
  
  static struct tracer_flags tracer_flags = {

  	/* Don't display overruns and proc by default */

  	.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |

  	       TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,

  	.opts = trace_opts
  };

  static struct trace_array *graph_array;

  /*
   * DURATION column is being also used to display IRQ signs,
   * following values are used by print_graph_irq and others
   * to fill in space into DURATION column.
   */
  enum {
  	DURATION_FILL_FULL  = -1,
  	DURATION_FILL_START = -2,
  	DURATION_FILL_END   = -3,
  };
  
  static enum print_line_t
  print_graph_duration(unsigned long long duration, struct trace_seq *s,
  		     u32 flags);

  /* Add a function return address to the trace stack on thread info.*/
  int

  ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
  			 unsigned long frame_pointer)

  {

  	unsigned long long calltime;

  	int index;
  
  	if (!current->ret_stack)
  		return -EBUSY;

  	/*
  	 * We must make sure the ret_stack is tested before we read
  	 * anything else.
  	 */
  	smp_rmb();

  	/* The return trace stack is full */
  	if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
  		atomic_inc(&current->trace_overrun);
  		return -EBUSY;
  	}

  	calltime = trace_clock_local();

  	index = ++current->curr_ret_stack;
  	barrier();
  	current->ret_stack[index].ret = ret;
  	current->ret_stack[index].func = func;

  	current->ret_stack[index].calltime = calltime;

  	current->ret_stack[index].subtime = 0;

  	current->ret_stack[index].fp = frame_pointer;

  	*depth = index;
  
  	return 0;
  }
  
  /* Retrieve a function return address to the trace stack on thread info.*/

  static void

  ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
  			unsigned long frame_pointer)

  {
  	int index;
  
  	index = current->curr_ret_stack;
  
  	if (unlikely(index < 0)) {
  		ftrace_graph_stop();
  		WARN_ON(1);
  		/* Might as well panic, otherwise we have no where to go */
  		*ret = (unsigned long)panic;
  		return;
  	}

  #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
  	/*
  	 * The arch may choose to record the frame pointer used
  	 * and check it here to make sure that it is what we expect it
  	 * to be. If gcc does not set the place holder of the return
  	 * address in the frame pointer, and does a copy instead, then
  	 * the function graph trace will fail. This test detects this
  	 * case.
  	 *
  	 * Currently, x86_32 with optimize for size (-Os) makes the latest
  	 * gcc do the above.
  	 */
  	if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
  		ftrace_graph_stop();
  		WARN(1, "Bad frame pointer: expected %lx, received %lx
  "

  		     "  from func %ps return to %lx
  ",

  		     current->ret_stack[index].fp,
  		     frame_pointer,
  		     (void *)current->ret_stack[index].func,
  		     current->ret_stack[index].ret);
  		*ret = (unsigned long)panic;
  		return;
  	}
  #endif

  	*ret = current->ret_stack[index].ret;
  	trace->func = current->ret_stack[index].func;
  	trace->calltime = current->ret_stack[index].calltime;
  	trace->overrun = atomic_read(&current->trace_overrun);
  	trace->depth = index;

  }
  
  /*
   * Send the trace to the ring-buffer.
   * @return the original return address.
   */

  unsigned long ftrace_return_to_handler(unsigned long frame_pointer)

  {
  	struct ftrace_graph_ret trace;
  	unsigned long ret;

  	ftrace_pop_return_trace(&trace, &ret, frame_pointer);

  	trace.rettime = trace_clock_local();

  	ftrace_graph_return(&trace);

  	barrier();
  	current->curr_ret_stack--;

  
  	if (unlikely(!ret)) {
  		ftrace_graph_stop();
  		WARN_ON(1);
  		/* Might as well panic. What else to do? */
  		ret = (unsigned long)panic;
  	}
  
  	return ret;
  }

  int __trace_graph_entry(struct trace_array *tr,

  				struct ftrace_graph_ent *trace,
  				unsigned long flags,
  				int pc)
  {
  	struct ftrace_event_call *call = &event_funcgraph_entry;
  	struct ring_buffer_event *event;

  	struct ring_buffer *buffer = tr->buffer;

  	struct ftrace_graph_ent_entry *entry;

  	if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))

  		return 0;

  	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,

  					  sizeof(*entry), flags, pc);
  	if (!event)
  		return 0;
  	entry	= ring_buffer_event_data(event);
  	entry->graph_ent			= *trace;

  	if (!filter_current_check_discard(buffer, call, entry, event))
  		ring_buffer_unlock_commit(buffer, event);

  
  	return 1;
  }

  static inline int ftrace_graph_ignore_irqs(void)
  {

  	if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))

  		return 0;
  
  	return in_irq();
  }

  int trace_graph_entry(struct ftrace_graph_ent *trace)
  {
  	struct trace_array *tr = graph_array;
  	struct trace_array_cpu *data;
  	unsigned long flags;
  	long disabled;
  	int ret;
  	int cpu;
  	int pc;

  	if (!ftrace_trace_task(current))
  		return 0;

  	/* trace it when it is-nested-in or is a function enabled. */

  	if (!(trace->depth || ftrace_graph_addr(trace->func)) ||
  	      ftrace_graph_ignore_irqs())

  		return 0;
  
  	local_irq_save(flags);
  	cpu = raw_smp_processor_id();
  	data = tr->data[cpu];
  	disabled = atomic_inc_return(&data->disabled);
  	if (likely(disabled == 1)) {
  		pc = preempt_count();
  		ret = __trace_graph_entry(tr, trace, flags, pc);
  	} else {
  		ret = 0;
  	}

  
  	atomic_dec(&data->disabled);
  	local_irq_restore(flags);
  
  	return ret;
  }

  int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
  {
  	if (tracing_thresh)
  		return 1;
  	else
  		return trace_graph_entry(trace);
  }

  static void
  __trace_graph_function(struct trace_array *tr,
  		unsigned long ip, unsigned long flags, int pc)
  {
  	u64 time = trace_clock_local();
  	struct ftrace_graph_ent ent = {
  		.func  = ip,
  		.depth = 0,
  	};
  	struct ftrace_graph_ret ret = {
  		.func     = ip,
  		.depth    = 0,
  		.calltime = time,
  		.rettime  = time,
  	};
  
  	__trace_graph_entry(tr, &ent, flags, pc);
  	__trace_graph_return(tr, &ret, flags, pc);
  }
  
  void
  trace_graph_function(struct trace_array *tr,
  		unsigned long ip, unsigned long parent_ip,
  		unsigned long flags, int pc)
  {

  	__trace_graph_function(tr, ip, flags, pc);
  }

  void __trace_graph_return(struct trace_array *tr,

  				struct ftrace_graph_ret *trace,
  				unsigned long flags,
  				int pc)
  {
  	struct ftrace_event_call *call = &event_funcgraph_exit;
  	struct ring_buffer_event *event;

  	struct ring_buffer *buffer = tr->buffer;

  	struct ftrace_graph_ret_entry *entry;

  	if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))

  		return;

  	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,

  					  sizeof(*entry), flags, pc);
  	if (!event)
  		return;
  	entry	= ring_buffer_event_data(event);
  	entry->ret				= *trace;

  	if (!filter_current_check_discard(buffer, call, entry, event))
  		ring_buffer_unlock_commit(buffer, event);

  }
  
  void trace_graph_return(struct ftrace_graph_ret *trace)
  {
  	struct trace_array *tr = graph_array;
  	struct trace_array_cpu *data;
  	unsigned long flags;
  	long disabled;
  	int cpu;
  	int pc;
  
  	local_irq_save(flags);
  	cpu = raw_smp_processor_id();
  	data = tr->data[cpu];
  	disabled = atomic_inc_return(&data->disabled);
  	if (likely(disabled == 1)) {
  		pc = preempt_count();
  		__trace_graph_return(tr, trace, flags, pc);
  	}

  	atomic_dec(&data->disabled);
  	local_irq_restore(flags);
  }

  void set_graph_array(struct trace_array *tr)
  {
  	graph_array = tr;
  
  	/* Make graph_array visible before we start tracing */
  
  	smp_mb();
  }

  void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
  {
  	if (tracing_thresh &&
  	    (trace->rettime - trace->calltime < tracing_thresh))
  		return;
  	else
  		trace_graph_return(trace);
  }

  static int graph_trace_init(struct trace_array *tr)
  {

  	int ret;

  	set_graph_array(tr);

  	if (tracing_thresh)
  		ret = register_ftrace_graph(&trace_graph_thresh_return,
  					    &trace_graph_thresh_entry);
  	else
  		ret = register_ftrace_graph(&trace_graph_return,
  					    &trace_graph_entry);

  	if (ret)
  		return ret;
  	tracing_start_cmdline_record();
  
  	return 0;

  }
  
  static void graph_trace_reset(struct trace_array *tr)
  {

  	tracing_stop_cmdline_record();
  	unregister_ftrace_graph();

  }

  static int max_bytes_for_cpu;

  
  static enum print_line_t
  print_graph_cpu(struct trace_seq *s, int cpu)
  {

  	int ret;

  	/*
  	 * Start with a space character - to make it stand out
  	 * to the right a bit when trace output is pasted into
  	 * email:
  	 */

  	ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);

  	if (!ret)

  		return TRACE_TYPE_PARTIAL_LINE;

  	return TRACE_TYPE_HANDLED;
  }

  #define TRACE_GRAPH_PROCINFO_LENGTH	14
  
  static enum print_line_t
  print_graph_proc(struct trace_seq *s, pid_t pid)
  {

  	char comm[TASK_COMM_LEN];

  	/* sign + log10(MAX_INT) + '\0' */
  	char pid_str[11];

  	int spaces = 0;
  	int ret;
  	int len;
  	int i;

  	trace_find_cmdline(pid, comm);

  	comm[7] = '\0';
  	sprintf(pid_str, "%d", pid);
  
  	/* 1 stands for the "-" character */
  	len = strlen(comm) + strlen(pid_str) + 1;
  
  	if (len < TRACE_GRAPH_PROCINFO_LENGTH)
  		spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
  
  	/* First spaces to align center */
  	for (i = 0; i < spaces / 2; i++) {
  		ret = trace_seq_printf(s, " ");
  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}
  
  	ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;
  
  	/* Last spaces to align center */
  	for (i = 0; i < spaces - (spaces / 2); i++) {
  		ret = trace_seq_printf(s, " ");
  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}
  	return TRACE_TYPE_HANDLED;
  }

  static enum print_line_t
  print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
  {

  	if (!trace_seq_putc(s, ' '))

  		return 0;

  	return trace_print_lat_fmt(s, entry);

  }

  /* If the pid changed since the last trace, output this event */

  static enum print_line_t

  verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)

  {

  	pid_t prev_pid;

  	pid_t *last_pid;

  	int ret;

  	if (!data)

  		return TRACE_TYPE_HANDLED;

  	last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);

  
  	if (*last_pid == pid)

  		return TRACE_TYPE_HANDLED;

  	prev_pid = *last_pid;
  	*last_pid = pid;

  	if (prev_pid == -1)
  		return TRACE_TYPE_HANDLED;

  /*
   * Context-switch trace line:
  
   ------------------------------------------
   | 1)  migration/0--1  =>  sshd-1755
   ------------------------------------------
  
   */
  	ret = trace_seq_printf(s,

  		" ------------------------------------------
  ");

  	if (!ret)

  		return TRACE_TYPE_PARTIAL_LINE;

  
  	ret = print_graph_cpu(s, cpu);
  	if (ret == TRACE_TYPE_PARTIAL_LINE)

  		return TRACE_TYPE_PARTIAL_LINE;

  
  	ret = print_graph_proc(s, prev_pid);
  	if (ret == TRACE_TYPE_PARTIAL_LINE)

  		return TRACE_TYPE_PARTIAL_LINE;

  
  	ret = trace_seq_printf(s, " => ");
  	if (!ret)

  		return TRACE_TYPE_PARTIAL_LINE;

  
  	ret = print_graph_proc(s, pid);
  	if (ret == TRACE_TYPE_PARTIAL_LINE)

  		return TRACE_TYPE_PARTIAL_LINE;

  
  	ret = trace_seq_printf(s,
  		"
   ------------------------------------------
  
  ");
  	if (!ret)

  		return TRACE_TYPE_PARTIAL_LINE;

  	return TRACE_TYPE_HANDLED;

  }

  static struct ftrace_graph_ret_entry *
  get_return_for_leaf(struct trace_iterator *iter,

  		struct ftrace_graph_ent_entry *curr)
  {

  	struct fgraph_data *data = iter->private;
  	struct ring_buffer_iter *ring_iter = NULL;

  	struct ring_buffer_event *event;
  	struct ftrace_graph_ret_entry *next;

  	/*
  	 * If the previous output failed to write to the seq buffer,
  	 * then we just reuse the data from before.
  	 */
  	if (data && data->failed) {
  		curr = &data->ent;
  		next = &data->ret;
  	} else {

  		ring_iter = iter->buffer_iter[iter->cpu];
  
  		/* First peek to compare current entry and the next one */
  		if (ring_iter)
  			event = ring_buffer_iter_peek(ring_iter, NULL);
  		else {
  			/*
  			 * We need to consume the current entry to see
  			 * the next one.
  			 */

  			ring_buffer_consume(iter->tr->buffer, iter->cpu,
  					    NULL, NULL);

  			event = ring_buffer_peek(iter->tr->buffer, iter->cpu,

  						 NULL, NULL);

  		}

  		if (!event)
  			return NULL;
  
  		next = ring_buffer_event_data(event);

  		if (data) {
  			/*
  			 * Save current and next entries for later reference
  			 * if the output fails.
  			 */
  			data->ent = *curr;

  			/*
  			 * If the next event is not a return type, then
  			 * we only care about what type it is. Otherwise we can
  			 * safely copy the entire event.
  			 */
  			if (next->ent.type == TRACE_GRAPH_RET)
  				data->ret = *next;
  			else
  				data->ret.ent.type = next->ent.type;

  		}
  	}

  
  	if (next->ent.type != TRACE_GRAPH_RET)

  		return NULL;

  
  	if (curr->ent.pid != next->ent.pid ||
  			curr->graph_ent.func != next->ret.func)

  		return NULL;

  	/* this is a leaf, now advance the iterator */
  	if (ring_iter)
  		ring_buffer_read(ring_iter, NULL);
  
  	return next;

  }

  static int print_graph_abs_time(u64 t, struct trace_seq *s)
  {
  	unsigned long usecs_rem;
  
  	usecs_rem = do_div(t, NSEC_PER_SEC);
  	usecs_rem /= 1000;
  
  	return trace_seq_printf(s, "%5lu.%06lu |  ",
  			(unsigned long)t, usecs_rem);
  }

  static enum print_line_t

  print_graph_irq(struct trace_iterator *iter, unsigned long addr,

  		enum trace_type type, int cpu, pid_t pid, u32 flags)

  {
  	int ret;

  	struct trace_seq *s = &iter->seq;

  
  	if (addr < (unsigned long)__irqentry_text_start ||
  		addr >= (unsigned long)__irqentry_text_end)
  		return TRACE_TYPE_UNHANDLED;

  	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
  		/* Absolute time */
  		if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
  			ret = print_graph_abs_time(iter->ts, s);
  			if (!ret)
  				return TRACE_TYPE_PARTIAL_LINE;
  		}

  		/* Cpu */
  		if (flags & TRACE_GRAPH_PRINT_CPU) {
  			ret = print_graph_cpu(s, cpu);
  			if (ret == TRACE_TYPE_PARTIAL_LINE)
  				return TRACE_TYPE_PARTIAL_LINE;
  		}

  		/* Proc */
  		if (flags & TRACE_GRAPH_PRINT_PROC) {
  			ret = print_graph_proc(s, pid);
  			if (ret == TRACE_TYPE_PARTIAL_LINE)
  				return TRACE_TYPE_PARTIAL_LINE;
  			ret = trace_seq_printf(s, " | ");
  			if (!ret)
  				return TRACE_TYPE_PARTIAL_LINE;
  		}

  	}

  	/* No overhead */

  	ret = print_graph_duration(DURATION_FILL_START, s, flags);
  	if (ret != TRACE_TYPE_HANDLED)
  		return ret;

  	if (type == TRACE_GRAPH_ENT)
  		ret = trace_seq_printf(s, "==========>");
  	else
  		ret = trace_seq_printf(s, "<==========");
  
  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;

  	ret = print_graph_duration(DURATION_FILL_END, s, flags);
  	if (ret != TRACE_TYPE_HANDLED)
  		return ret;

  	ret = trace_seq_printf(s, "
  ");

  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;
  	return TRACE_TYPE_HANDLED;
  }

  enum print_line_t
  trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)

  {
  	unsigned long nsecs_rem = do_div(duration, 1000);

  	/* log10(ULONG_MAX) + '\0' */
  	char msecs_str[21];
  	char nsecs_str[5];
  	int ret, len;
  	int i;
  
  	sprintf(msecs_str, "%lu", (unsigned long) duration);
  
  	/* Print msecs */

  	ret = trace_seq_printf(s, "%s", msecs_str);

  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;
  
  	len = strlen(msecs_str);
  
  	/* Print nsecs (we don't want to exceed 7 numbers) */
  	if (len < 7) {

  		size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
  
  		snprintf(nsecs_str, slen, "%03lu", nsecs_rem);

  		ret = trace_seq_printf(s, ".%s", nsecs_str);
  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  		len += strlen(nsecs_str);
  	}
  
  	ret = trace_seq_printf(s, " us ");
  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;
  
  	/* Print remaining spaces to fit the row's width */
  	for (i = len; i < 7; i++) {
  		ret = trace_seq_printf(s, " ");
  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}

  	return TRACE_TYPE_HANDLED;
  }
  
  static enum print_line_t

  print_graph_duration(unsigned long long duration, struct trace_seq *s,
  		     u32 flags)

  {

  	int ret = -1;

  	if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
  	    !(trace_flags & TRACE_ITER_CONTEXT_INFO))
  			return TRACE_TYPE_HANDLED;

  
  	/* No real adata, just filling the column with spaces */
  	switch (duration) {
  	case DURATION_FILL_FULL:
  		ret = trace_seq_printf(s, "              |  ");
  		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
  	case DURATION_FILL_START:
  		ret = trace_seq_printf(s, "  ");
  		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
  	case DURATION_FILL_END:
  		ret = trace_seq_printf(s, " |");
  		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
  	}
  
  	/* Signal a overhead of time execution to the output */
  	if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
  		/* Duration exceeded 100 msecs */
  		if (duration > 100000ULL)
  			ret = trace_seq_printf(s, "! ");
  		/* Duration exceeded 10 msecs */
  		else if (duration > 10000ULL)
  			ret = trace_seq_printf(s, "+ ");
  	}
  
  	/*
  	 * The -1 means we either did not exceed the duration tresholds
  	 * or we dont want to print out the overhead. Either way we need
  	 * to fill out the space.
  	 */
  	if (ret == -1)
  		ret = trace_seq_printf(s, "  ");
  
  	/* Catching here any failure happenned above */
  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;

  
  	ret = trace_print_graph_duration(duration, s);
  	if (ret != TRACE_TYPE_HANDLED)
  		return ret;

  
  	ret = trace_seq_printf(s, "|  ");
  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;

  	return TRACE_TYPE_HANDLED;

  }

  /* Case of a leaf function on its call entry */

  static enum print_line_t

  print_graph_entry_leaf(struct trace_iterator *iter,

  		struct ftrace_graph_ent_entry *entry,

  		struct ftrace_graph_ret_entry *ret_entry,
  		struct trace_seq *s, u32 flags)

  {

  	struct fgraph_data *data = iter->private;

  	struct ftrace_graph_ret *graph_ret;

  	struct ftrace_graph_ent *call;
  	unsigned long long duration;

  	int ret;

  	int i;

  	graph_ret = &ret_entry->ret;
  	call = &entry->graph_ent;
  	duration = graph_ret->rettime - graph_ret->calltime;

  	if (data) {

  		struct fgraph_cpu_data *cpu_data;

  		int cpu = iter->cpu;

  
  		cpu_data = per_cpu_ptr(data->cpu_data, cpu);

  
  		/*
  		 * Comments display at + 1 to depth. Since
  		 * this is a leaf function, keep the comments
  		 * equal to this depth.
  		 */

  		cpu_data->depth = call->depth - 1;
  
  		/* No need to keep this function around for this depth */
  		if (call->depth < FTRACE_RETFUNC_DEPTH)
  			cpu_data->enter_funcs[call->depth] = 0;

  	}

  	/* Overhead and duration */
  	ret = print_graph_duration(duration, s, flags);
  	if (ret == TRACE_TYPE_PARTIAL_LINE)

  		return TRACE_TYPE_PARTIAL_LINE;

  	/* Function */
  	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
  		ret = trace_seq_printf(s, " ");
  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}

  	ret = trace_seq_printf(s, "%ps();
  ", (void *)call->func);

  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;
  
  	return TRACE_TYPE_HANDLED;
  }
  
  static enum print_line_t

  print_graph_entry_nested(struct trace_iterator *iter,
  			 struct ftrace_graph_ent_entry *entry,

  			 struct trace_seq *s, int cpu, u32 flags)

  {

  	struct ftrace_graph_ent *call = &entry->graph_ent;

  	struct fgraph_data *data = iter->private;
  	int ret;
  	int i;
  
  	if (data) {

  		struct fgraph_cpu_data *cpu_data;

  		int cpu = iter->cpu;

  		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
  		cpu_data->depth = call->depth;
  
  		/* Save this function pointer to see if the exit matches */
  		if (call->depth < FTRACE_RETFUNC_DEPTH)
  			cpu_data->enter_funcs[call->depth] = call->func;

  	}

  	/* No time */

  	ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
  	if (ret != TRACE_TYPE_HANDLED)
  		return ret;

  	/* Function */

  	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
  		ret = trace_seq_printf(s, " ");

  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;

  	}

  	ret = trace_seq_printf(s, "%ps() {
  ", (void *)call->func);

  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;

  	/*
  	 * we already consumed the current entry to check the next one
  	 * and see if this is a leaf.
  	 */
  	return TRACE_TYPE_NO_CONSUME;

  }
  
  static enum print_line_t

  print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,

  		     int type, unsigned long addr, u32 flags)

  {

  	struct fgraph_data *data = iter->private;

  	struct trace_entry *ent = iter->ent;

  	int cpu = iter->cpu;
  	int ret;

  	/* Pid */

  	if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)

  		return TRACE_TYPE_PARTIAL_LINE;

  	if (type) {
  		/* Interrupt */

  		ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);

  		if (ret == TRACE_TYPE_PARTIAL_LINE)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}

  	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
  		return 0;

  	/* Absolute time */

  	if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {

  		ret = print_graph_abs_time(iter->ts, s);
  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}

  	/* Cpu */

  	if (flags & TRACE_GRAPH_PRINT_CPU) {

  		ret = print_graph_cpu(s, cpu);

  		if (ret == TRACE_TYPE_PARTIAL_LINE)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}
  
  	/* Proc */

  	if (flags & TRACE_GRAPH_PRINT_PROC) {

  		ret = print_graph_proc(s, ent->pid);

  		if (ret == TRACE_TYPE_PARTIAL_LINE)
  			return TRACE_TYPE_PARTIAL_LINE;
  
  		ret = trace_seq_printf(s, " | ");

  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}

  	/* Latency format */
  	if (trace_flags & TRACE_ITER_LATENCY_FMT) {
  		ret = print_graph_lat_fmt(s, ent);
  		if (ret == TRACE_TYPE_PARTIAL_LINE)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}

  	return 0;
  }

  /*
   * Entry check for irq code
   *
   * returns 1 if
   *  - we are inside irq code

   *  - we just entered irq code

   *
   * retunns 0 if
   *  - funcgraph-interrupts option is set
   *  - we are not inside irq code
   */
  static int
  check_irq_entry(struct trace_iterator *iter, u32 flags,
  		unsigned long addr, int depth)
  {
  	int cpu = iter->cpu;

  	int *depth_irq;

  	struct fgraph_data *data = iter->private;

  	/*
  	 * If we are either displaying irqs, or we got called as
  	 * a graph event and private data does not exist,
  	 * then we bypass the irq check.
  	 */
  	if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
  	    (!data))

  		return 0;

  	depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);

  	/*
  	 * We are inside the irq code
  	 */
  	if (*depth_irq >= 0)
  		return 1;
  
  	if ((addr < (unsigned long)__irqentry_text_start) ||
  	    (addr >= (unsigned long)__irqentry_text_end))
  		return 0;
  
  	/*
  	 * We are entering irq code.
  	 */
  	*depth_irq = depth;
  	return 1;
  }
  
  /*
   * Return check for irq code
   *
   * returns 1 if
   *  - we are inside irq code
   *  - we just left irq code
   *
   * returns 0 if
   *  - funcgraph-interrupts option is set
   *  - we are not inside irq code
   */
  static int
  check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
  {
  	int cpu = iter->cpu;

  	int *depth_irq;

  	struct fgraph_data *data = iter->private;

  	/*
  	 * If we are either displaying irqs, or we got called as
  	 * a graph event and private data does not exist,
  	 * then we bypass the irq check.
  	 */
  	if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
  	    (!data))

  		return 0;

  	depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);

  	/*
  	 * We are not inside the irq code.
  	 */
  	if (*depth_irq == -1)
  		return 0;
  
  	/*
  	 * We are inside the irq code, and this is returning entry.
  	 * Let's not trace it and clear the entry depth, since
  	 * we are out of irq code.
  	 *
  	 * This condition ensures that we 'leave the irq code' once
  	 * we are out of the entry depth. Thus protecting us from
  	 * the RETURN entry loss.
  	 */
  	if (*depth_irq >= depth) {
  		*depth_irq = -1;
  		return 1;
  	}
  
  	/*
  	 * We are inside the irq code, and this is not the entry.
  	 */
  	return 1;
  }

  static enum print_line_t
  print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,

  			struct trace_iterator *iter, u32 flags)

  {

  	struct fgraph_data *data = iter->private;

  	struct ftrace_graph_ent *call = &field->graph_ent;
  	struct ftrace_graph_ret_entry *leaf_ret;

  	static enum print_line_t ret;
  	int cpu = iter->cpu;

  	if (check_irq_entry(iter, flags, call->func, call->depth))
  		return TRACE_TYPE_HANDLED;

  	if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))

  		return TRACE_TYPE_PARTIAL_LINE;

  	leaf_ret = get_return_for_leaf(iter, field);
  	if (leaf_ret)

  		ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);

  	else

  		ret = print_graph_entry_nested(iter, field, s, cpu, flags);

  	if (data) {
  		/*
  		 * If we failed to write our output, then we need to make
  		 * note of it. Because we already consumed our entry.
  		 */
  		if (s->full) {
  			data->failed = 1;
  			data->cpu = cpu;
  		} else
  			data->failed = 0;
  	}
  
  	return ret;

  }
  
  static enum print_line_t

  print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,

  		   struct trace_entry *ent, struct trace_iterator *iter,
  		   u32 flags)

  {

  	unsigned long long duration = trace->rettime - trace->calltime;

  	struct fgraph_data *data = iter->private;
  	pid_t pid = ent->pid;
  	int cpu = iter->cpu;

  	int func_match = 1;

  	int ret;
  	int i;

  	if (check_irq_return(iter, flags, trace->depth))
  		return TRACE_TYPE_HANDLED;

  	if (data) {

  		struct fgraph_cpu_data *cpu_data;
  		int cpu = iter->cpu;
  
  		cpu_data = per_cpu_ptr(data->cpu_data, cpu);

  
  		/*
  		 * Comments display at + 1 to depth. This is the
  		 * return from a function, we now want the comments
  		 * to display at the same level of the bracket.
  		 */

  		cpu_data->depth = trace->depth - 1;
  
  		if (trace->depth < FTRACE_RETFUNC_DEPTH) {
  			if (cpu_data->enter_funcs[trace->depth] != trace->func)
  				func_match = 0;
  			cpu_data->enter_funcs[trace->depth] = 0;
  		}

  	}

  	if (print_graph_prologue(iter, s, 0, 0, flags))

  		return TRACE_TYPE_PARTIAL_LINE;

  	/* Overhead and duration */
  	ret = print_graph_duration(duration, s, flags);
  	if (ret == TRACE_TYPE_PARTIAL_LINE)

  		return TRACE_TYPE_PARTIAL_LINE;

  	/* Closing brace */

  	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
  		ret = trace_seq_printf(s, " ");

  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;

  	}

  	/*
  	 * If the return function does not have a matching entry,
  	 * then the entry was lost. Instead of just printing
  	 * the '}' and letting the user guess what function this
  	 * belongs to, write out the function name.
  	 */
  	if (func_match) {
  		ret = trace_seq_printf(s, "}
  ");
  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	} else {

  		ret = trace_seq_printf(s, "} /* %ps */
  ", (void *)trace->func);

  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;
  	}

  	/* Overrun */

  	if (flags & TRACE_GRAPH_PRINT_OVERRUN) {

  		ret = trace_seq_printf(s, " (Overruns: %lu)
  ",
  					trace->overrun);

  		if (!ret)
  			return TRACE_TYPE_PARTIAL_LINE;

  	}

  	ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
  			      cpu, pid, flags);

  	if (ret == TRACE_TYPE_PARTIAL_LINE)
  		return TRACE_TYPE_PARTIAL_LINE;

  	return TRACE_TYPE_HANDLED;
  }

  static enum print_line_t

  print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
  		    struct trace_iterator *iter, u32 flags)

  {

  	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);

  	struct fgraph_data *data = iter->private;

  	struct trace_event *event;

  	int depth = 0;

  	int ret;

  	int i;
  
  	if (data)

  		depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;

  	if (print_graph_prologue(iter, s, 0, 0, flags))

  		return TRACE_TYPE_PARTIAL_LINE;

  	/* No time */

  	ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
  	if (ret != TRACE_TYPE_HANDLED)
  		return ret;

  	/* Indentation */

  	if (depth > 0)
  		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {

  			ret = trace_seq_printf(s, " ");
  			if (!ret)
  				return TRACE_TYPE_PARTIAL_LINE;
  		}
  
  	/* The comment */

  	ret = trace_seq_printf(s, "/* ");
  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;

  	switch (iter->ent->type) {
  	case TRACE_BPRINT:
  		ret = trace_print_bprintk_msg_only(iter);
  		if (ret != TRACE_TYPE_HANDLED)
  			return ret;
  		break;
  	case TRACE_PRINT:
  		ret = trace_print_printk_msg_only(iter);
  		if (ret != TRACE_TYPE_HANDLED)
  			return ret;
  		break;
  	default:
  		event = ftrace_find_event(ent->type);
  		if (!event)
  			return TRACE_TYPE_UNHANDLED;

  		ret = event->funcs->trace(iter, sym_flags, event);

  		if (ret != TRACE_TYPE_HANDLED)
  			return ret;
  	}

  	/* Strip ending newline */
  	if (s->buffer[s->len - 1] == '
  ') {
  		s->buffer[s->len - 1] = '\0';
  		s->len--;
  	}

  	ret = trace_seq_printf(s, " */
  ");
  	if (!ret)
  		return TRACE_TYPE_PARTIAL_LINE;
  
  	return TRACE_TYPE_HANDLED;
  }

  enum print_line_t

  print_graph_function_flags(struct trace_iterator *iter, u32 flags)

  {

  	struct ftrace_graph_ent_entry *field;
  	struct fgraph_data *data = iter->private;

  	struct trace_entry *entry = iter->ent;

  	struct trace_seq *s = &iter->seq;

  	int cpu = iter->cpu;
  	int ret;
  
  	if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
  		per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
  		return TRACE_TYPE_HANDLED;
  	}
  
  	/*
  	 * If the last output failed, there's a possibility we need
  	 * to print out the missing entry which would never go out.
  	 */
  	if (data && data->failed) {
  		field = &data->ent;
  		iter->cpu = data->cpu;

  		ret = print_graph_entry(field, s, iter, flags);

  		if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
  			per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
  			ret = TRACE_TYPE_NO_CONSUME;
  		}
  		iter->cpu = cpu;
  		return ret;
  	}

  	switch (entry->type) {
  	case TRACE_GRAPH_ENT: {

  		/*
  		 * print_graph_entry() may consume the current event,
  		 * thus @field may become invalid, so we need to save it.
  		 * sizeof(struct ftrace_graph_ent_entry) is very small,
  		 * it can be safely saved at the stack.
  		 */

  		struct ftrace_graph_ent_entry saved;

  		trace_assign_type(field, entry);

  		saved = *field;

  		return print_graph_entry(&saved, s, iter, flags);

  	}
  	case TRACE_GRAPH_RET: {
  		struct ftrace_graph_ret_entry *field;
  		trace_assign_type(field, entry);

  		return print_graph_return(&field->ret, s, entry, iter, flags);

  	}

  	case TRACE_STACK:
  	case TRACE_FN:
  		/* dont trace stack and functions as comments */
  		return TRACE_TYPE_UNHANDLED;

  	default:

  		return print_graph_comment(s, entry, iter, flags);

  	}

  
  	return TRACE_TYPE_HANDLED;

  }

  static enum print_line_t

  print_graph_function(struct trace_iterator *iter)
  {

  	return print_graph_function_flags(iter, tracer_flags.val);

  }
  
  static enum print_line_t

  print_graph_function_event(struct trace_iterator *iter, int flags,
  			   struct trace_event *event)

  {
  	return print_graph_function(iter);
  }

  static void print_lat_header(struct seq_file *s, u32 flags)

  {
  	static const char spaces[] = "                "	/* 16 spaces */
  		"    "					/* 4 spaces */
  		"                 ";			/* 17 spaces */
  	int size = 0;

  	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)

  		size += 16;

  	if (flags & TRACE_GRAPH_PRINT_CPU)

  		size += 4;

  	if (flags & TRACE_GRAPH_PRINT_PROC)

  		size += 17;
  
  	seq_printf(s, "#%.*s  _-----=> irqs-off        
  ", size, spaces);
  	seq_printf(s, "#%.*s / _----=> need-resched    
  ", size, spaces);
  	seq_printf(s, "#%.*s| / _---=> hardirq/softirq 
  ", size, spaces);
  	seq_printf(s, "#%.*s|| / _--=> preempt-depth   
  ", size, spaces);

  	seq_printf(s, "#%.*s||| /                      
  ", size, spaces);

  }

  static void __print_graph_headers_flags(struct seq_file *s, u32 flags)

  {

  	int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
  
  	if (lat)

  		print_lat_header(s, flags);

  	/* 1st line */

  	seq_printf(s, "#");

  	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)

  		seq_printf(s, "     TIME       ");

  	if (flags & TRACE_GRAPH_PRINT_CPU)

  		seq_printf(s, " CPU");

  	if (flags & TRACE_GRAPH_PRINT_PROC)

  		seq_printf(s, "  TASK/PID       ");
  	if (lat)

  		seq_printf(s, "||||");

  	if (flags & TRACE_GRAPH_PRINT_DURATION)

  		seq_printf(s, "  DURATION   ");
  	seq_printf(s, "               FUNCTION CALLS
  ");

  
  	/* 2nd line */

  	seq_printf(s, "#");

  	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)

  		seq_printf(s, "      |         ");

  	if (flags & TRACE_GRAPH_PRINT_CPU)

  		seq_printf(s, " |  ");

  	if (flags & TRACE_GRAPH_PRINT_PROC)

  		seq_printf(s, "   |    |        ");
  	if (lat)

  		seq_printf(s, "||||");

  	if (flags & TRACE_GRAPH_PRINT_DURATION)

  		seq_printf(s, "   |   |      ");
  	seq_printf(s, "               |   |   |   |
  ");

  }

  void print_graph_headers(struct seq_file *s)

  {
  	print_graph_headers_flags(s, tracer_flags.val);
  }

  void print_graph_headers_flags(struct seq_file *s, u32 flags)
  {
  	struct trace_iterator *iter = s->private;

  	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
  		return;

  	if (trace_flags & TRACE_ITER_LATENCY_FMT) {
  		/* print nothing if the buffers are empty */
  		if (trace_empty(iter))
  			return;
  
  		print_trace_header(s, iter);

  	}

  
  	__print_graph_headers_flags(s, flags);
  }

  void graph_trace_open(struct trace_iterator *iter)

  {

  	/* pid and depth on the last trace processed */

  	struct fgraph_data *data;

  	int cpu;

  	iter->private = NULL;
  
  	data = kzalloc(sizeof(*data), GFP_KERNEL);

  	if (!data)

  		goto out_err;
  
  	data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
  	if (!data->cpu_data)
  		goto out_err_free;
  
  	for_each_possible_cpu(cpu) {
  		pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
  		int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
  		int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);

  		int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);

  		*pid = -1;
  		*depth = 0;
  		*ignore = 0;

  		*depth_irq = -1;

  	}

  	iter->private = data;

  
  	return;
  
   out_err_free:
  	kfree(data);
   out_err:
  	pr_warning("function graph tracer: not enough memory
  ");

  }

  void graph_trace_close(struct trace_iterator *iter)

  {

  	struct fgraph_data *data = iter->private;
  
  	if (data) {
  		free_percpu(data->cpu_data);
  		kfree(data);
  	}

  }

  static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
  {
  	if (bit == TRACE_GRAPH_PRINT_IRQS)
  		ftrace_graph_skip_irqs = !set;
  
  	return 0;
  }

  static struct trace_event_functions graph_functions = {
  	.trace		= print_graph_function_event,
  };

  static struct trace_event graph_trace_entry_event = {
  	.type		= TRACE_GRAPH_ENT,

  	.funcs		= &graph_functions,

  };
  
  static struct trace_event graph_trace_ret_event = {
  	.type		= TRACE_GRAPH_RET,

  	.funcs		= &graph_functions

  };

  static struct tracer graph_trace __read_mostly = {

  	.name		= "function_graph",

  	.open		= graph_trace_open,

  	.pipe_open	= graph_trace_open,

  	.close		= graph_trace_close,

  	.pipe_close	= graph_trace_close,

  	.wait_pipe	= poll_wait_pipe,

  	.init		= graph_trace_init,
  	.reset		= graph_trace_reset,

  	.print_line	= print_graph_function,
  	.print_header	= print_graph_headers,

  	.flags		= &tracer_flags,

  	.set_flag	= func_graph_set_flag,

  #ifdef CONFIG_FTRACE_SELFTEST
  	.selftest	= trace_selftest_startup_function_graph,
  #endif

  };
  
  static __init int init_graph_trace(void)
  {

  	max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);

  	if (!register_ftrace_event(&graph_trace_entry_event)) {
  		pr_warning("Warning: could not register graph trace events
  ");
  		return 1;
  	}
  
  	if (!register_ftrace_event(&graph_trace_ret_event)) {
  		pr_warning("Warning: could not register graph trace events
  ");
  		return 1;
  	}

  	return register_tracer(&graph_trace);
  }
  
  device_initcall(init_graph_trace);