text: /*
   * Infrastructure for profiling code inserted by 'gcc -pg'.
   *
   * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   *
   * Originally ported from the -rt patch by:
   *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
   *
   * Based on code in the latency_tracer, that is:
   *
   *  Copyright (C) 2004-2006 Ingo Molnar
   *  Copyright (C) 2004 Nadia Yvette Chambers
   */
  
  #include <linux/stop_machine.h>
  #include <linux/clocksource.h>
  #include <linux/kallsyms.h>
  #include <linux/seq_file.h>
  #include <linux/suspend.h>
  #include <linux/debugfs.h>
  #include <linux/hardirq.h>
  #include <linux/kthread.h>
  #include <linux/uaccess.h>
  #include <linux/bsearch.h>
  #include <linux/module.h>
  #include <linux/ftrace.h>
  #include <linux/sysctl.h>
  #include <linux/slab.h>
  #include <linux/ctype.h>
  #include <linux/sort.h>
  #include <linux/list.h>
  #include <linux/hash.h>
  #include <linux/rcupdate.h>
  
  #include <trace/events/sched.h>
  
  #include <asm/setup.h>
  
  #include "trace_output.h"
  #include "trace_stat.h"
  
  #define FTRACE_WARN_ON(cond)			\
  	({					\
  		int ___r = cond;		\
  		if (WARN_ON(___r))		\
  			ftrace_kill();		\
  		___r;				\
  	})
  
  #define FTRACE_WARN_ON_ONCE(cond)		\
  	({					\
  		int ___r = cond;		\
  		if (WARN_ON_ONCE(___r))		\
  			ftrace_kill();		\
  		___r;				\
  	})
  
  /* hash bits for specific function selection */
  #define FTRACE_HASH_BITS 7
  #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  #define FTRACE_HASH_DEFAULT_BITS 10
  #define FTRACE_HASH_MAX_BITS 12
  
  #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
  
  #ifdef CONFIG_DYNAMIC_FTRACE
  #define INIT_REGEX_LOCK(opsname)	\
  	.regex_lock	= __MUTEX_INITIALIZER(opsname.regex_lock),
  #else
  #define INIT_REGEX_LOCK(opsname)
  #endif
  
  static struct ftrace_ops ftrace_list_end __read_mostly = {
  	.func		= ftrace_stub,
  	.flags		= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
  };
  
  /* ftrace_enabled is a method to turn ftrace on or off */
  int ftrace_enabled __read_mostly;
  static int last_ftrace_enabled;
  
  /* Quick disabling of function tracer. */
  int function_trace_stop __read_mostly;
  
  /* Current function tracing op */
  struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
  /* What to set function_trace_op to */
  static struct ftrace_ops *set_function_trace_op;
  
  /* List for set_ftrace_pid's pids. */
  LIST_HEAD(ftrace_pids);
  struct ftrace_pid {
  	struct list_head list;
  	struct pid *pid;
  };
  
  /*
   * ftrace_disabled is set when an anomaly is discovered.
   * ftrace_disabled is much stronger than ftrace_enabled.
   */
  static int ftrace_disabled __read_mostly;
  
  static DEFINE_MUTEX(ftrace_lock);
  
  static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
  static struct ftrace_ops *ftrace_control_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_pid_function __read_mostly = ftrace_stub;
  static struct ftrace_ops global_ops;
  static struct ftrace_ops control_ops;
  
  #if ARCH_SUPPORTS_FTRACE_OPS
  static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
  				 struct ftrace_ops *op, struct pt_regs *regs);
  #else
  /* See comment below, where ftrace_ops_list_func is defined */
  static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
  #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
  #endif
  
  /*
   * Traverse the ftrace_global_list, invoking all entries.  The reason that we
   * can use rcu_dereference_raw_notrace() 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_notrace() calls are needed to handle
   * concurrent insertions into the ftrace_global_list.
   *
   * Silly Alpha and silly pointer-speculation compiler optimizations!
   */
  #define do_for_each_ftrace_op(op, list)			\
  	op = rcu_dereference_raw_notrace(list);			\
  	do
  
  /*
   * Optimized for just a single item in the list (as that is the normal case).
   */
  #define while_for_each_ftrace_op(op)				\
  	while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&	\
  	       unlikely((op) != &ftrace_list_end))
  
  static inline void ftrace_ops_init(struct ftrace_ops *ops)
  {
  #ifdef CONFIG_DYNAMIC_FTRACE
  	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
  		mutex_init(&ops->regex_lock);
  		ops->flags |= FTRACE_OPS_FL_INITIALIZED;
  	}
  #endif
  }
  
  /**
   * ftrace_nr_registered_ops - return number of ops registered
   *
   * Returns the number of ftrace_ops registered and tracing functions
   */
  int ftrace_nr_registered_ops(void)
  {
  	struct ftrace_ops *ops;
  	int cnt = 0;
  
  	mutex_lock(&ftrace_lock);
  
  	for (ops = ftrace_ops_list;
  	     ops != &ftrace_list_end; ops = ops->next)
  		cnt++;
  
  	mutex_unlock(&ftrace_lock);
  
  	return cnt;
  }
  
  static void
  ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
  			struct ftrace_ops *op, struct pt_regs *regs)
  {
  	int bit;
  
  	bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
  	if (bit < 0)
  		return;
  
  	do_for_each_ftrace_op(op, ftrace_global_list) {
  		op->func(ip, parent_ip, op, regs);
  	} while_for_each_ftrace_op(op);
  
  	trace_clear_recursion(bit);
  }
  
  static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
  			    struct ftrace_ops *op, struct pt_regs *regs)
  {
  	if (!test_tsk_trace_trace(current))
  		return;
  
  	ftrace_pid_function(ip, parent_ip, op, regs);
  }
  
  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
   *
   * This NULLs the ftrace function and in essence stops
   * tracing.  There may be lag
   */
  void clear_ftrace_function(void)
  {
  	ftrace_trace_function = ftrace_stub;
  	ftrace_pid_function = ftrace_stub;
  }
  
  static void control_ops_disable_all(struct ftrace_ops *ops)
  {
  	int cpu;
  
  	for_each_possible_cpu(cpu)
  		*per_cpu_ptr(ops->disabled, cpu) = 1;
  }
  
  static int control_ops_alloc(struct ftrace_ops *ops)
  {
  	int __percpu *disabled;
  
  	disabled = alloc_percpu(int);
  	if (!disabled)
  		return -ENOMEM;
  
  	ops->disabled = disabled;
  	control_ops_disable_all(ops);
  	return 0;
  }
  
  static void control_ops_free(struct ftrace_ops *ops)
  {
  	free_percpu(ops->disabled);
  }
  
  static void update_global_ops(void)
  {
  	ftrace_func_t func;
  
  	/*
  	 * If there's only one function registered, then call that
  	 * function directly. Otherwise, we need to iterate over the
  	 * registered callers.
  	 */
  	if (ftrace_global_list == &ftrace_list_end ||
  	    ftrace_global_list->next == &ftrace_list_end) {
  		func = ftrace_global_list->func;
  		/*
  		 * As we are calling the function directly.
  		 * If it does not have recursion protection,
  		 * the function_trace_op needs to be updated
  		 * accordingly.
  		 */
  		if (ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE)
  			global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
  		else
  			global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
  	} else {
  		func = ftrace_global_list_func;
  		/* The list has its own recursion protection. */
  		global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
  	}
  
  
  	/* If we filter on pids, update to use the pid function */
  	if (!list_empty(&ftrace_pids)) {
  		set_ftrace_pid_function(func);
  		func = ftrace_pid_func;
  	}
  
  	global_ops.func = func;
  }
  
  static void ftrace_sync(struct work_struct *work)
  {
  	/*
  	 * This function is just a stub to implement a hard force
  	 * of synchronize_sched(). This requires synchronizing
  	 * tasks even in userspace and idle.
  	 *
  	 * Yes, function tracing is rude.
  	 */
  }
  
  static void ftrace_sync_ipi(void *data)
  {
  	/* Probably not needed, but do it anyway */
  	smp_rmb();
  }
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  static void update_function_graph_func(void);
  #else
  static inline void update_function_graph_func(void) { }
  #endif
  
  static void update_ftrace_function(void)
  {
  	ftrace_func_t func;
  
  	update_global_ops();
  
  	/*
  	 * If we are at the end of the list and this ops is
  	 * recursion safe and not dynamic and the arch supports passing ops,
  	 * then have the mcount trampoline call the function directly.
  	 */
  	if (ftrace_ops_list == &ftrace_list_end ||
  	    (ftrace_ops_list->next == &ftrace_list_end &&
  	     !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
  	     (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
  	     !FTRACE_FORCE_LIST_FUNC)) {
  		/* Set the ftrace_ops that the arch callback uses */
  		if (ftrace_ops_list == &global_ops)
  			set_function_trace_op = ftrace_global_list;
  		else
  			set_function_trace_op = ftrace_ops_list;
  		func = ftrace_ops_list->func;
  	} else {
  		/* Just use the default ftrace_ops */
  		set_function_trace_op = &ftrace_list_end;
  		func = ftrace_ops_list_func;
  	}
  
  	/* If there's no change, then do nothing more here */
  	if (ftrace_trace_function == func)
  		return;
  
  	update_function_graph_func();
  
  	/*
  	 * If we are using the list function, it doesn't care
  	 * about the function_trace_ops.
  	 */
  	if (func == ftrace_ops_list_func) {
  		ftrace_trace_function = func;
  		/*
  		 * Don't even bother setting function_trace_ops,
  		 * it would be racy to do so anyway.
  		 */
  		return;
  	}
  
  #ifndef CONFIG_DYNAMIC_FTRACE
  	/*
  	 * For static tracing, we need to be a bit more careful.
  	 * The function change takes affect immediately. Thus,
  	 * we need to coorditate the setting of the function_trace_ops
  	 * with the setting of the ftrace_trace_function.
  	 *
  	 * Set the function to the list ops, which will call the
  	 * function we want, albeit indirectly, but it handles the
  	 * ftrace_ops and doesn't depend on function_trace_op.
  	 */
  	ftrace_trace_function = ftrace_ops_list_func;
  	/*
  	 * Make sure all CPUs see this. Yes this is slow, but static
  	 * tracing is slow and nasty to have enabled.
  	 */
  	schedule_on_each_cpu(ftrace_sync);
  	/* Now all cpus are using the list ops. */
  	function_trace_op = set_function_trace_op;
  	/* Make sure the function_trace_op is visible on all CPUs */
  	smp_wmb();
  	/* Nasty way to force a rmb on all cpus */
  	smp_call_function(ftrace_sync_ipi, NULL, 1);
  	/* OK, we are all set to update the ftrace_trace_function now! */
  #endif /* !CONFIG_DYNAMIC_FTRACE */
  
  	ftrace_trace_function = func;
  }
  
  static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
  {
  	ops->next = *list;
  	/*
  	 * 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 list.
  	 */
  	rcu_assign_pointer(*list, ops);
  }
  
  static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
  {
  	struct ftrace_ops **p;
  
  	/*
  	 * If we are removing the last function, then simply point
  	 * to the ftrace_stub.
  	 */
  	if (*list == ops && ops->next == &ftrace_list_end) {
  		*list = &ftrace_list_end;
  		return 0;
  	}
  
  	for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
  		if (*p == ops)
  			break;
  
  	if (*p != ops)
  		return -1;
  
  	*p = (*p)->next;
  	return 0;
  }
  
  static void add_ftrace_list_ops(struct ftrace_ops **list,
  				struct ftrace_ops *main_ops,
  				struct ftrace_ops *ops)
  {
  	int first = *list == &ftrace_list_end;
  	add_ftrace_ops(list, ops);
  	if (first)
  		add_ftrace_ops(&ftrace_ops_list, main_ops);
  }
  
  static int remove_ftrace_list_ops(struct ftrace_ops **list,
  				  struct ftrace_ops *main_ops,
  				  struct ftrace_ops *ops)
  {
  	int ret = remove_ftrace_ops(list, ops);
  	if (!ret && *list == &ftrace_list_end)
  		ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
  	return ret;
  }
  
  static int __register_ftrace_function(struct ftrace_ops *ops)
  {
  	if (FTRACE_WARN_ON(ops == &global_ops))
  		return -EINVAL;
  
  	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
  		return -EBUSY;
  
  	/* We don't support both control and global flags set. */
  	if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
  		return -EINVAL;
  
  #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
  	/*
  	 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
  	 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
  	 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
  	 */
  	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
  	    !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
  		return -EINVAL;
  
  	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
  		ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
  #endif
  
  	if (!core_kernel_data((unsigned long)ops))
  		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
  
  	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
  		add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
  		ops->flags |= FTRACE_OPS_FL_ENABLED;
  	} else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
  		if (control_ops_alloc(ops))
  			return -ENOMEM;
  		add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
  	} else
  		add_ftrace_ops(&ftrace_ops_list, ops);
  
  	if (ftrace_enabled)
  		update_ftrace_function();
  
  	return 0;
  }
  
  static int __unregister_ftrace_function(struct ftrace_ops *ops)
  {
  	int ret;
  
  	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
  		return -EBUSY;
  
  	if (FTRACE_WARN_ON(ops == &global_ops))
  		return -EINVAL;
  
  	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
  		ret = remove_ftrace_list_ops(&ftrace_global_list,
  					     &global_ops, ops);
  		if (!ret)
  			ops->flags &= ~FTRACE_OPS_FL_ENABLED;
  	} else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
  		ret = remove_ftrace_list_ops(&ftrace_control_list,
  					     &control_ops, ops);
  	} else
  		ret = remove_ftrace_ops(&ftrace_ops_list, ops);
  
  	if (ret < 0)
  		return ret;
  
  	if (ftrace_enabled)
  		update_ftrace_function();
  
  	return 0;
  }
  
  static void ftrace_update_pid_func(void)
  {
  	/* Only do something if we are tracing something */
  	if (ftrace_trace_function == ftrace_stub)
  		return;
  
  	update_ftrace_function();
  }
  
  #ifdef CONFIG_FUNCTION_PROFILER
  struct ftrace_profile {
  	struct hlist_node		node;
  	unsigned long			ip;
  	unsigned long			counter;
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  	unsigned long long		time;
  	unsigned long long		time_squared;
  #endif
  };
  
  struct ftrace_profile_page {
  	struct ftrace_profile_page	*next;
  	unsigned long			index;
  	struct ftrace_profile		records[];
  };
  
  struct ftrace_profile_stat {
  	atomic_t			disabled;
  	struct hlist_head		*hash;
  	struct ftrace_profile_page	*pages;
  	struct ftrace_profile_page	*start;
  	struct tracer_stat		stat;
  };
  
  #define PROFILE_RECORDS_SIZE						\
  	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
  
  #define PROFILES_PER_PAGE					\
  	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
  
  static int ftrace_profile_enabled __read_mostly;
  
  /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
  static DEFINE_MUTEX(ftrace_profile_lock);
  
  static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
  
  #define FTRACE_PROFILE_HASH_BITS 10
  #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
  
  static void *
  function_stat_next(void *v, int idx)
  {
  	struct ftrace_profile *rec = v;
  	struct ftrace_profile_page *pg;
  
  	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
  
   again:
  	if (idx != 0)
  		rec++;
  
  	if ((void *)rec >= (void *)&pg->records[pg->index]) {
  		pg = pg->next;
  		if (!pg)
  			return NULL;
  		rec = &pg->records[0];
  		if (!rec->counter)
  			goto again;
  	}
  
  	return rec;
  }
  
  static void *function_stat_start(struct tracer_stat *trace)
  {
  	struct ftrace_profile_stat *stat =
  		container_of(trace, struct ftrace_profile_stat, stat);
  
  	if (!stat || !stat->start)
  		return NULL;
  
  	return function_stat_next(&stat->start->records[0], 0);
  }
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  /* function graph compares on total time */
  static int function_stat_cmp(void *p1, void *p2)
  {
  	struct ftrace_profile *a = p1;
  	struct ftrace_profile *b = p2;
  
  	if (a->time < b->time)
  		return -1;
  	if (a->time > b->time)
  		return 1;
  	else
  		return 0;
  }
  #else
  /* not function graph compares against hits */
  static int function_stat_cmp(void *p1, void *p2)
  {
  	struct ftrace_profile *a = p1;
  	struct ftrace_profile *b = p2;
  
  	if (a->counter < b->counter)
  		return -1;
  	if (a->counter > b->counter)
  		return 1;
  	else
  		return 0;
  }
  #endif
  
  static int function_stat_headers(struct seq_file *m)
  {
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  	seq_printf(m, "  Function                               "
  		   "Hit    Time            Avg             s^2\n"
  		      "  --------                               "
  		   "---    ----            ---             ---\n");
  #else
  	seq_printf(m, "  Function                               Hit\n"
  		      "  --------                               ---\n");
  #endif
  	return 0;
  }
  
  static int function_stat_show(struct seq_file *m, void *v)
  {
  	struct ftrace_profile *rec = v;
  	char str[KSYM_SYMBOL_LEN];
  	int ret = 0;
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  	static struct trace_seq s;
  	unsigned long long avg;
  	unsigned long long stddev;
  #endif
  	mutex_lock(&ftrace_profile_lock);
  
  	/* we raced with function_profile_reset() */
  	if (unlikely(rec->counter == 0)) {
  		ret = -EBUSY;
  		goto out;
  	}
  
  	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
  	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  	seq_printf(m, "    ");
  	avg = rec->time;
  	do_div(avg, rec->counter);
  
  	/* Sample standard deviation (s^2) */
  	if (rec->counter <= 1)
  		stddev = 0;
  	else {
  		/*
  		 * Apply Welford's method:
  		 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
  		 */
  		stddev = rec->counter * rec->time_squared -
  			 rec->time * rec->time;
  
  		/*
  		 * Divide only 1000 for ns^2 -> us^2 conversion.
  		 * trace_print_graph_duration will divide 1000 again.
  		 */
  		do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
  	}
  
  	trace_seq_init(&s);
  	trace_print_graph_duration(rec->time, &s);
  	trace_seq_puts(&s, "    ");
  	trace_print_graph_duration(avg, &s);
  	trace_seq_puts(&s, "    ");
  	trace_print_graph_duration(stddev, &s);
  	trace_print_seq(m, &s);
  #endif
  	seq_putc(m, '\n');
  out:
  	mutex_unlock(&ftrace_profile_lock);
  
  	return ret;
  }
  
  static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
  {
  	struct ftrace_profile_page *pg;
  
  	pg = stat->pages = stat->start;
  
  	while (pg) {
  		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
  		pg->index = 0;
  		pg = pg->next;
  	}
  
  	memset(stat->hash, 0,
  	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
  }
  
  int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
  {
  	struct ftrace_profile_page *pg;
  	int functions;
  	int pages;
  	int i;
  
  	/* If we already allocated, do nothing */
  	if (stat->pages)
  		return 0;
  
  	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
  	if (!stat->pages)
  		return -ENOMEM;
  
  #ifdef CONFIG_DYNAMIC_FTRACE
  	functions = ftrace_update_tot_cnt;
  #else
  	/*
  	 * We do not know the number of functions that exist because
  	 * dynamic tracing is what counts them. With past experience
  	 * we have around 20K functions. That should be more than enough.
  	 * It is highly unlikely we will execute every function in
  	 * the kernel.
  	 */
  	functions = 20000;
  #endif
  
  	pg = stat->start = stat->pages;
  
  	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
  
  	for (i = 1; i < pages; i++) {
  		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
  		if (!pg->next)
  			goto out_free;
  		pg = pg->next;
  	}
  
  	return 0;
  
   out_free:
  	pg = stat->start;
  	while (pg) {
  		unsigned long tmp = (unsigned long)pg;
  
  		pg = pg->next;
  		free_page(tmp);
  	}
  
  	stat->pages = NULL;
  	stat->start = NULL;
  
  	return -ENOMEM;
  }
  
  static int ftrace_profile_init_cpu(int cpu)
  {
  	struct ftrace_profile_stat *stat;
  	int size;
  
  	stat = &per_cpu(ftrace_profile_stats, cpu);
  
  	if (stat->hash) {
  		/* If the profile is already created, simply reset it */
  		ftrace_profile_reset(stat);
  		return 0;
  	}
  
  	/*
  	 * We are profiling all functions, but usually only a few thousand
  	 * functions are hit. We'll make a hash of 1024 items.
  	 */
  	size = FTRACE_PROFILE_HASH_SIZE;
  
  	stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
  
  	if (!stat->hash)
  		return -ENOMEM;
  
  	/* Preallocate the function profiling pages */
  	if (ftrace_profile_pages_init(stat) < 0) {
  		kfree(stat->hash);
  		stat->hash = NULL;
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  static int ftrace_profile_init(void)
  {
  	int cpu;
  	int ret = 0;
  
  	for_each_possible_cpu(cpu) {
  		ret = ftrace_profile_init_cpu(cpu);
  		if (ret)
  			break;
  	}
  
  	return ret;
  }
  
  /* interrupts must be disabled */
  static struct ftrace_profile *
  ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
  {
  	struct ftrace_profile *rec;
  	struct hlist_head *hhd;
  	unsigned long key;
  
  	key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
  	hhd = &stat->hash[key];
  
  	if (hlist_empty(hhd))
  		return NULL;
  
  	hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
  		if (rec->ip == ip)
  			return rec;
  	}
  
  	return NULL;
  }
  
  static void ftrace_add_profile(struct ftrace_profile_stat *stat,
  			       struct ftrace_profile *rec)
  {
  	unsigned long key;
  
  	key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
  	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
  }
  
  /*
   * The memory is already allocated, this simply finds a new record to use.
   */
  static struct ftrace_profile *
  ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
  {
  	struct ftrace_profile *rec = NULL;
  
  	/* prevent recursion (from NMIs) */
  	if (atomic_inc_return(&stat->disabled) != 1)
  		goto out;
  
  	/*
  	 * Try to find the function again since an NMI
  	 * could have added it
  	 */
  	rec = ftrace_find_profiled_func(stat, ip);
  	if (rec)
  		goto out;
  
  	if (stat->pages->index == PROFILES_PER_PAGE) {
  		if (!stat->pages->next)
  			goto out;
  		stat->pages = stat->pages->next;
  	}
  
  	rec = &stat->pages->records[stat->pages->index++];
  	rec->ip = ip;
  	ftrace_add_profile(stat, rec);
  
   out:
  	atomic_dec(&stat->disabled);
  
  	return rec;
  }
  
  static void
  function_profile_call(unsigned long ip, unsigned long parent_ip,
  		      struct ftrace_ops *ops, struct pt_regs *regs)
  {
  	struct ftrace_profile_stat *stat;
  	struct ftrace_profile *rec;
  	unsigned long flags;
  
  	if (!ftrace_profile_enabled)
  		return;
  
  	local_irq_save(flags);
  
  	stat = &__get_cpu_var(ftrace_profile_stats);
  	if (!stat->hash || !ftrace_profile_enabled)
  		goto out;
  
  	rec = ftrace_find_profiled_func(stat, ip);
  	if (!rec) {
  		rec = ftrace_profile_alloc(stat, ip);
  		if (!rec)
  			goto out;
  	}
  
  	rec->counter++;
   out:
  	local_irq_restore(flags);
  }
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  static int profile_graph_entry(struct ftrace_graph_ent *trace)
  {
  	function_profile_call(trace->func, 0, NULL, NULL);
  	return 1;
  }
  
  static void profile_graph_return(struct ftrace_graph_ret *trace)
  {
  	struct ftrace_profile_stat *stat;
  	unsigned long long calltime;
  	struct ftrace_profile *rec;
  	unsigned long flags;
  
  	local_irq_save(flags);
  	stat = &__get_cpu_var(ftrace_profile_stats);
  	if (!stat->hash || !ftrace_profile_enabled)
  		goto out;
  
  	/* If the calltime was zero'd ignore it */
  	if (!trace->calltime)
  		goto out;
  
  	calltime = trace->rettime - trace->calltime;
  
  	if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
  		int index;
  
  		index = trace->depth;
  
  		/* Append this call time to the parent time to subtract */
  		if (index)
  			current->ret_stack[index - 1].subtime += calltime;
  
  		if (current->ret_stack[index].subtime < calltime)
  			calltime -= current->ret_stack[index].subtime;
  		else
  			calltime = 0;
  	}
  
  	rec = ftrace_find_profiled_func(stat, trace->func);
  	if (rec) {
  		rec->time += calltime;
  		rec->time_squared += calltime * calltime;
  	}
  
   out:
  	local_irq_restore(flags);
  }
  
  static int register_ftrace_profiler(void)
  {
  	return register_ftrace_graph(&profile_graph_return,
  				     &profile_graph_entry);
  }
  
  static void unregister_ftrace_profiler(void)
  {
  	unregister_ftrace_graph();
  }
  #else
  static struct ftrace_ops ftrace_profile_ops __read_mostly = {
  	.func		= function_profile_call,
  	.flags		= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
  	INIT_REGEX_LOCK(ftrace_profile_ops)
  };
  
  static int register_ftrace_profiler(void)
  {
  	return register_ftrace_function(&ftrace_profile_ops);
  }
  
  static void unregister_ftrace_profiler(void)
  {
  	unregister_ftrace_function(&ftrace_profile_ops);
  }
  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  
  static ssize_t
  ftrace_profile_write(struct file *filp, const char __user *ubuf,
  		     size_t cnt, loff_t *ppos)
  {
  	unsigned long val;
  	int ret;
  
  	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
  	if (ret)
  		return ret;
  
  	val = !!val;
  
  	mutex_lock(&ftrace_profile_lock);
  	if (ftrace_profile_enabled ^ val) {
  		if (val) {
  			ret = ftrace_profile_init();
  			if (ret < 0) {
  				cnt = ret;
  				goto out;
  			}
  
  			ret = register_ftrace_profiler();
  			if (ret < 0) {
  				cnt = ret;
  				goto out;
  			}
  			ftrace_profile_enabled = 1;
  		} else {
  			ftrace_profile_enabled = 0;
  			/*
  			 * unregister_ftrace_profiler calls stop_machine
  			 * so this acts like an synchronize_sched.
  			 */
  			unregister_ftrace_profiler();
  		}
  	}
   out:
  	mutex_unlock(&ftrace_profile_lock);
  
  	*ppos += cnt;
  
  	return cnt;
  }
  
  static ssize_t
  ftrace_profile_read(struct file *filp, char __user *ubuf,
  		     size_t cnt, loff_t *ppos)
  {
  	char buf[64];		/* big enough to hold a number */
  	int r;
  
  	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
  	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
  }
  
  static const struct file_operations ftrace_profile_fops = {
  	.open		= tracing_open_generic,
  	.read		= ftrace_profile_read,
  	.write		= ftrace_profile_write,
  	.llseek		= default_llseek,
  };
  
  /* used to initialize the real stat files */
  static struct tracer_stat function_stats __initdata = {
  	.name		= "functions",
  	.stat_start	= function_stat_start,
  	.stat_next	= function_stat_next,
  	.stat_cmp	= function_stat_cmp,
  	.stat_headers	= function_stat_headers,
  	.stat_show	= function_stat_show
  };
  
  static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
  {
  	struct ftrace_profile_stat *stat;
  	struct dentry *entry;
  	char *name;
  	int ret;
  	int cpu;
  
  	for_each_possible_cpu(cpu) {
  		stat = &per_cpu(ftrace_profile_stats, cpu);
  
  		/* allocate enough for function name + cpu number */
  		name = kmalloc(32, GFP_KERNEL);
  		if (!name) {
  			/*
  			 * The files created are permanent, if something happens
  			 * we still do not free memory.
  			 */
  			WARN(1,
  			     "Could not allocate stat file for cpu %d\n",
  			     cpu);
  			return;
  		}
  		stat->stat = function_stats;
  		snprintf(name, 32, "function%d", cpu);
  		stat->stat.name = name;
  		ret = register_stat_tracer(&stat->stat);
  		if (ret) {
  			WARN(1,
  			     "Could not register function stat for cpu %d\n",
  			     cpu);
  			kfree(name);
  			return;
  		}
  	}
  
  	entry = debugfs_create_file("function_profile_enabled", 0644,
  				    d_tracer, NULL, &ftrace_profile_fops);
  	if (!entry)
  		pr_warning("Could not create debugfs "
  			   "'function_profile_enabled' entry\n");
  }
  
  #else /* CONFIG_FUNCTION_PROFILER */
  static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
  {
  }
  #endif /* CONFIG_FUNCTION_PROFILER */
  
  static struct pid * const ftrace_swapper_pid = &init_struct_pid;
  
  #ifdef CONFIG_DYNAMIC_FTRACE
  
  #ifndef CONFIG_FTRACE_MCOUNT_RECORD
  # error Dynamic ftrace depends on MCOUNT_RECORD
  #endif
  
  static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
  
  struct ftrace_func_probe {
  	struct hlist_node	node;
  	struct ftrace_probe_ops	*ops;
  	unsigned long		flags;
  	unsigned long		ip;
  	void			*data;
  	struct list_head	free_list;
  };
  
  struct ftrace_func_entry {
  	struct hlist_node hlist;
  	unsigned long ip;
  };
  
  struct ftrace_hash {
  	unsigned long		size_bits;
  	struct hlist_head	*buckets;
  	unsigned long		count;
  	struct rcu_head		rcu;
  };
  
  /*
   * We make these constant because no one should touch them,
   * but they are used as the default "empty hash", to avoid allocating
   * it all the time. These are in a read only section such that if
   * anyone does try to modify it, it will cause an exception.
   */
  static const struct hlist_head empty_buckets[1];
  static const struct ftrace_hash empty_hash = {
  	.buckets = (struct hlist_head *)empty_buckets,
  };
  #define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
  
  static struct ftrace_ops global_ops = {
  	.func			= ftrace_stub,
  	.notrace_hash		= EMPTY_HASH,
  	.filter_hash		= EMPTY_HASH,
  	.flags			= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
  	INIT_REGEX_LOCK(global_ops)
  };
  
  struct ftrace_page {
  	struct ftrace_page	*next;
  	struct dyn_ftrace	*records;
  	int			index;
  	int			size;
  };
  
  static struct ftrace_page *ftrace_new_pgs;
  
  #define ENTRY_SIZE sizeof(struct dyn_ftrace)
  #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
  
  /* estimate from running different kernels */
  #define NR_TO_INIT		10000
  
  static struct ftrace_page	*ftrace_pages_start;
  static struct ftrace_page	*ftrace_pages;
  
  static bool ftrace_hash_empty(struct ftrace_hash *hash)
  {
  	return !hash || !hash->count;
  }
  
  static struct ftrace_func_entry *
  ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
  {
  	unsigned long key;
  	struct ftrace_func_entry *entry;
  	struct hlist_head *hhd;
  
  	if (ftrace_hash_empty(hash))
  		return NULL;
  
  	if (hash->size_bits > 0)
  		key = hash_long(ip, hash->size_bits);
  	else
  		key = 0;
  
  	hhd = &hash->buckets[key];
  
  	hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
  		if (entry->ip == ip)
  			return entry;
  	}
  	return NULL;
  }
  
  static void __add_hash_entry(struct ftrace_hash *hash,
  			     struct ftrace_func_entry *entry)
  {
  	struct hlist_head *hhd;
  	unsigned long key;
  
  	if (hash->size_bits)
  		key = hash_long(entry->ip, hash->size_bits);
  	else
  		key = 0;
  
  	hhd = &hash->buckets[key];
  	hlist_add_head(&entry->hlist, hhd);
  	hash->count++;
  }
  
  static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
  {
  	struct ftrace_func_entry *entry;
  
  	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
  	if (!entry)
  		return -ENOMEM;
  
  	entry->ip = ip;
  	__add_hash_entry(hash, entry);
  
  	return 0;
  }
  
  static void
  free_hash_entry(struct ftrace_hash *hash,
  		  struct ftrace_func_entry *entry)
  {
  	hlist_del(&entry->hlist);
  	kfree(entry);
  	hash->count--;
  }
  
  static void
  remove_hash_entry(struct ftrace_hash *hash,
  		  struct ftrace_func_entry *entry)
  {
  	hlist_del(&entry->hlist);
  	hash->count--;
  }
  
  static void ftrace_hash_clear(struct ftrace_hash *hash)
  {
  	struct hlist_head *hhd;
  	struct hlist_node *tn;
  	struct ftrace_func_entry *entry;
  	int size = 1 << hash->size_bits;
  	int i;
  
  	if (!hash->count)
  		return;
  
  	for (i = 0; i < size; i++) {
  		hhd = &hash->buckets[i];
  		hlist_for_each_entry_safe(entry, tn, hhd, hlist)
  			free_hash_entry(hash, entry);
  	}
  	FTRACE_WARN_ON(hash->count);
  }
  
  static void free_ftrace_hash(struct ftrace_hash *hash)
  {
  	if (!hash || hash == EMPTY_HASH)
  		return;
  	ftrace_hash_clear(hash);
  	kfree(hash->buckets);
  	kfree(hash);
  }
  
  static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
  {
  	struct ftrace_hash *hash;
  
  	hash = container_of(rcu, struct ftrace_hash, rcu);
  	free_ftrace_hash(hash);
  }
  
  static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
  {
  	if (!hash || hash == EMPTY_HASH)
  		return;
  	call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
  }
  
  void ftrace_free_filter(struct ftrace_ops *ops)
  {
  	ftrace_ops_init(ops);
  	free_ftrace_hash(ops->filter_hash);
  	free_ftrace_hash(ops->notrace_hash);
  }
  
  static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
  {
  	struct ftrace_hash *hash;
  	int size;
  
  	hash = kzalloc(sizeof(*hash), GFP_KERNEL);
  	if (!hash)
  		return NULL;
  
  	size = 1 << size_bits;
  	hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
  
  	if (!hash->buckets) {
  		kfree(hash);
  		return NULL;
  	}
  
  	hash->size_bits = size_bits;
  
  	return hash;
  }
  
  static struct ftrace_hash *
  alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
  {
  	struct ftrace_func_entry *entry;
  	struct ftrace_hash *new_hash;
  	int size;
  	int ret;
  	int i;
  
  	new_hash = alloc_ftrace_hash(size_bits);
  	if (!new_hash)
  		return NULL;
  
  	/* Empty hash? */
  	if (ftrace_hash_empty(hash))
  		return new_hash;
  
  	size = 1 << hash->size_bits;
  	for (i = 0; i < size; i++) {
  		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
  			ret = add_hash_entry(new_hash, entry->ip);
  			if (ret < 0)
  				goto free_hash;
  		}
  	}
  
  	FTRACE_WARN_ON(new_hash->count != hash->count);
  
  	return new_hash;
  
   free_hash:
  	free_ftrace_hash(new_hash);
  	return NULL;
  }
  
  static void
  ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
  static void
  ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
  
  static int
  ftrace_hash_move(struct ftrace_ops *ops, int enable,
  		 struct ftrace_hash **dst, struct ftrace_hash *src)
  {
  	struct ftrace_func_entry *entry;
  	struct hlist_node *tn;
  	struct hlist_head *hhd;
  	struct ftrace_hash *old_hash;
  	struct ftrace_hash *new_hash;
  	int size = src->count;
  	int bits = 0;
  	int ret;
  	int i;
  
  	/*
  	 * Remove the current set, update the hash and add
  	 * them back.
  	 */
  	ftrace_hash_rec_disable(ops, enable);
  
  	/*
  	 * If the new source is empty, just free dst and assign it
  	 * the empty_hash.
  	 */
  	if (!src->count) {
  		free_ftrace_hash_rcu(*dst);
  		rcu_assign_pointer(*dst, EMPTY_HASH);
  		/* still need to update the function records */
  		ret = 0;
  		goto out;
  	}
  
  	/*
  	 * Make the hash size about 1/2 the # found
  	 */
  	for (size /= 2; size; size >>= 1)
  		bits++;
  
  	/* Don't allocate too much */
  	if (bits > FTRACE_HASH_MAX_BITS)
  		bits = FTRACE_HASH_MAX_BITS;
  
  	ret = -ENOMEM;
  	new_hash = alloc_ftrace_hash(bits);
  	if (!new_hash)
  		goto out;
  
  	size = 1 << src->size_bits;
  	for (i = 0; i < size; i++) {
  		hhd = &src->buckets[i];
  		hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
  			remove_hash_entry(src, entry);
  			__add_hash_entry(new_hash, entry);
  		}
  	}
  
  	old_hash = *dst;
  	rcu_assign_pointer(*dst, new_hash);
  	free_ftrace_hash_rcu(old_hash);
  
  	ret = 0;
   out:
  	/*
  	 * Enable regardless of ret:
  	 *  On success, we enable the new hash.
  	 *  On failure, we re-enable the original hash.
  	 */
  	ftrace_hash_rec_enable(ops, enable);
  
  	return ret;
  }
  
  /*
   * 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.
   *
   * This needs to be called with preemption disabled as
   * the hashes are freed with call_rcu_sched().
   */
  static int
  ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
  {
  	struct ftrace_hash *filter_hash;
  	struct ftrace_hash *notrace_hash;
  	int ret;
  
  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
  	/*
  	 * There's a small race when adding ops that the ftrace handler
  	 * that wants regs, may be called without them. We can not
  	 * allow that handler to be called if regs is NULL.
  	 */
  	if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
  		return 0;
  #endif
  
  	filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
  	notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
  
  	if ((ftrace_hash_empty(filter_hash) ||
  	     ftrace_lookup_ip(filter_hash, ip)) &&
  	    (ftrace_hash_empty(notrace_hash) ||
  	     !ftrace_lookup_ip(notrace_hash, ip)))
  		ret = 1;
  	else
  		ret = 0;
  
  	return ret;
  }
  
  /*
   * This is a double for. Do not use 'break' to break out of the loop,
   * you must use a goto.
   */
  #define do_for_each_ftrace_rec(pg, rec)					\
  	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
  		int _____i;						\
  		for (_____i = 0; _____i < pg->index; _____i++) {	\
  			rec = &pg->records[_____i];
  
  #define while_for_each_ftrace_rec()		\
  		}				\
  	}
  
  
  static int ftrace_cmp_recs(const void *a, const void *b)
  {
  	const struct dyn_ftrace *key = a;
  	const struct dyn_ftrace *rec = b;
  
  	if (key->flags < rec->ip)
  		return -1;
  	if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
  		return 1;
  	return 0;
  }
  
  static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
  {
  	struct ftrace_page *pg;
  	struct dyn_ftrace *rec;
  	struct dyn_ftrace key;
  
  	key.ip = start;
  	key.flags = end;	/* overload flags, as it is unsigned long */
  
  	for (pg = ftrace_pages_start; pg; pg = pg->next) {
  		if (end < pg->records[0].ip ||
  		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
  			continue;
  		rec = bsearch(&key, pg->records, pg->index,
  			      sizeof(struct dyn_ftrace),
  			      ftrace_cmp_recs);
  		if (rec)
  			return rec->ip;
  	}
  
  	return 0;
  }
  
  /**
   * ftrace_location - return true if the ip giving is a traced location
   * @ip: the instruction pointer to check
   *
   * Returns rec->ip if @ip given is a pointer to a ftrace location.
   * That is, the instruction that is either a NOP or call to
   * the function tracer. It checks the ftrace internal tables to
   * determine if the address belongs or not.
   */
  unsigned long ftrace_location(unsigned long ip)
  {
  	return ftrace_location_range(ip, ip);
  }
  
  /**
   * ftrace_text_reserved - return true if range contains an ftrace location
   * @start: start of range to search
   * @end: end of range to search (inclusive). @end points to the last byte to check.
   *
   * Returns 1 if @start and @end contains a ftrace location.
   * That is, the instruction that is either a NOP or call to
   * the function tracer. It checks the ftrace internal tables to
   * determine if the address belongs or not.
   */
  int ftrace_text_reserved(void *start, void *end)
  {
  	unsigned long ret;
  
  	ret = ftrace_location_range((unsigned long)start,
  				    (unsigned long)end);
  
  	return (int)!!ret;
  }
  
  static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
  				     int filter_hash,
  				     bool inc)
  {
  	struct ftrace_hash *hash;
  	struct ftrace_hash *other_hash;
  	struct ftrace_page *pg;
  	struct dyn_ftrace *rec;
  	int count = 0;
  	int all = 0;
  
  	/* Only update if the ops has been registered */
  	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
  		return;
  
  	/*
  	 * In the filter_hash case:
  	 *   If the count is zero, we update all records.
  	 *   Otherwise we just update the items in the hash.
  	 *
  	 * In the notrace_hash case:
  	 *   We enable the update in the hash.
  	 *   As disabling notrace means enabling the tracing,
  	 *   and enabling notrace means disabling, the inc variable
  	 *   gets inversed.
  	 */
  	if (filter_hash) {
  		hash = ops->filter_hash;
  		other_hash = ops->notrace_hash;
  		if (ftrace_hash_empty(hash))
  			all = 1;
  	} else {
  		inc = !inc;
  		hash = ops->notrace_hash;
  		other_hash = ops->filter_hash;
  		/*
  		 * If the notrace hash has no items,
  		 * then there's nothing to do.
  		 */
  		if (ftrace_hash_empty(hash))
  			return;
  	}
  
  	do_for_each_ftrace_rec(pg, rec) {
  		int in_other_hash = 0;
  		int in_hash = 0;
  		int match = 0;
  
  		if (all) {
  			/*
  			 * Only the filter_hash affects all records.
  			 * Update if the record is not in the notrace hash.
  			 */
  			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);
  
  			/*
  			 *
  			 */
  			if (filter_hash && in_hash && !in_other_hash)
  				match = 1;
  			else if (!filter_hash && in_hash &&
  				 (in_other_hash || ftrace_hash_empty(other_hash)))
  				match = 1;
  		}
  		if (!match)
  			continue;
  
  		if (inc) {
  			rec->flags++;
  			if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
  				return;
  			/*
  			 * If any ops wants regs saved for this function
  			 * then all ops will get saved regs.
  			 */
  			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
  				rec->flags |= FTRACE_FL_REGS;
  		} else {
  			if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
  				return;
  			rec->flags--;
  		}
  		count++;
  		/* Shortcut, if we handled all records, we are done. */
  		if (!all && count == hash->count)
  			return;
  	} while_for_each_ftrace_rec();
  }
  
  static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
  				    int filter_hash)
  {
  	__ftrace_hash_rec_update(ops, filter_hash, 0);
  }
  
  static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
  				   int filter_hash)
  {
  	__ftrace_hash_rec_update(ops, filter_hash, 1);
  }
  
  static void print_ip_ins(const char *fmt, unsigned char *p)
  {
  	int i;
  
  	printk(KERN_CONT "%s", fmt);
  
  	for (i = 0; i < MCOUNT_INSN_SIZE; i++)
  		printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
  }
  
  /**
   * ftrace_bug - report and shutdown function tracer
   * @failed: The failed type (EFAULT, EINVAL, EPERM)
   * @ip: The address that failed
   *
   * The arch code that enables or disables the function tracing
   * can call ftrace_bug() when it has detected a problem in
   * modifying the code. @failed should be one of either:
   * EFAULT - if the problem happens on reading the @ip address
   * EINVAL - if what is read at @ip is not what was expected
   * EPERM - if the problem happens on writting to the @ip address
   */
  void ftrace_bug(int failed, unsigned long ip)
  {
  	switch (failed) {
  	case -EFAULT:
  		FTRACE_WARN_ON_ONCE(1);
  		pr_info("ftrace faulted on modifying ");
  		print_ip_sym(ip);
  		break;
  	case -EINVAL:
  		FTRACE_WARN_ON_ONCE(1);
  		pr_info("ftrace failed to modify ");
  		print_ip_sym(ip);
  		print_ip_ins(" actual: ", (unsigned char *)ip);
  		printk(KERN_CONT "\n");
  		break;
  	case -EPERM:
  		FTRACE_WARN_ON_ONCE(1);
  		pr_info("ftrace faulted on writing ");
  		print_ip_sym(ip);
  		break;
  	default:
  		FTRACE_WARN_ON_ONCE(1);
  		pr_info("ftrace faulted on unknown error ");
  		print_ip_sym(ip);
  	}
  }
  
  static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
  {
  	unsigned long flag = 0UL;
  
  	/*
  	 * If we are updating calls:
  	 *
  	 *   If the record has a ref count, then we need to enable it
  	 *   because someone is using it.
  	 *
  	 *   Otherwise we make sure its disabled.
  	 *
  	 * If we are disabling calls, then disable all records that
  	 * are enabled.
  	 */
  	if (enable && (rec->flags & ~FTRACE_FL_MASK))
  		flag = FTRACE_FL_ENABLED;
  
  	/*
  	 * If enabling and the REGS flag does not match the REGS_EN, then
  	 * do not ignore this record. Set flags to fail the compare against
  	 * ENABLED.
  	 */
  	if (flag &&
  	    (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
  		flag |= FTRACE_FL_REGS;
  
  	/* If the state of this record hasn't changed, then do nothing */
  	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
  		return FTRACE_UPDATE_IGNORE;
  
  	if (flag) {
  		/* Save off if rec is being enabled (for return value) */
  		flag ^= rec->flags & FTRACE_FL_ENABLED;
  
  		if (update) {
  			rec->flags |= FTRACE_FL_ENABLED;
  			if (flag & FTRACE_FL_REGS) {
  				if (rec->flags & FTRACE_FL_REGS)
  					rec->flags |= FTRACE_FL_REGS_EN;
  				else
  					rec->flags &= ~FTRACE_FL_REGS_EN;
  			}
  		}
  
  		/*
  		 * If this record is being updated from a nop, then
  		 *   return UPDATE_MAKE_CALL.
  		 * Otherwise, if the EN flag is set, then return
  		 *   UPDATE_MODIFY_CALL_REGS to tell the caller to convert
  		 *   from the non-save regs, to a save regs function.
  		 * Otherwise,
  		 *   return UPDATE_MODIFY_CALL to tell the caller to convert
  		 *   from the save regs, to a non-save regs function.
  		 */
  		if (flag & FTRACE_FL_ENABLED)
  			return FTRACE_UPDATE_MAKE_CALL;
  		else if (rec->flags & FTRACE_FL_REGS_EN)
  			return FTRACE_UPDATE_MODIFY_CALL_REGS;
  		else
  			return FTRACE_UPDATE_MODIFY_CALL;
  	}
  
  	if (update) {
  		/* If there's no more users, clear all flags */
  		if (!(rec->flags & ~FTRACE_FL_MASK))
  			rec->flags = 0;
  		else
  			/* Just disable the record (keep REGS state) */
  			rec->flags &= ~FTRACE_FL_ENABLED;
  	}
  
  	return FTRACE_UPDATE_MAKE_NOP;
  }
  
  /**
   * ftrace_update_record, set a record that now is tracing or not
   * @rec: the record to update
   * @enable: set to 1 if the record is tracing, zero to force disable
   *
   * The records that represent all functions that can be traced need
   * to be updated when tracing has been enabled.
   */
  int ftrace_update_record(struct dyn_ftrace *rec, int enable)
  {
  	return ftrace_check_record(rec, enable, 1);
  }
  
  /**
   * ftrace_test_record, check if the record has been enabled or not
   * @rec: the record to test
   * @enable: set to 1 to check if enabled, 0 if it is disabled
   *
   * The arch code may need to test if a record is already set to
   * tracing to determine how to modify the function code that it
   * represents.
   */
  int ftrace_test_record(struct dyn_ftrace *rec, int enable)
  {
  	return ftrace_check_record(rec, enable, 0);
  }
  
  static int
  __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
  {
  	unsigned long ftrace_old_addr;
  	unsigned long ftrace_addr;
  	int ret;
  
  	ret = ftrace_update_record(rec, enable);
  
  	if (rec->flags & FTRACE_FL_REGS)
  		ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
  	else
  		ftrace_addr = (unsigned long)FTRACE_ADDR;
  
  	switch (ret) {
  	case FTRACE_UPDATE_IGNORE:
  		return 0;
  
  	case FTRACE_UPDATE_MAKE_CALL:
  		return ftrace_make_call(rec, ftrace_addr);
  
  	case FTRACE_UPDATE_MAKE_NOP:
  		return ftrace_make_nop(NULL, rec, ftrace_addr);
  
  	case FTRACE_UPDATE_MODIFY_CALL_REGS:
  	case FTRACE_UPDATE_MODIFY_CALL:
  		if (rec->flags & FTRACE_FL_REGS)
  			ftrace_old_addr = (unsigned long)FTRACE_ADDR;
  		else
  			ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
  
  		return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
  	}
  
  	return -1; /* unknow ftrace bug */
  }
  
  void __weak ftrace_replace_code(int enable)
  {
  	struct dyn_ftrace *rec;
  	struct ftrace_page *pg;
  	int failed;
  
  	if (unlikely(ftrace_disabled))
  		return;
  
  	do_for_each_ftrace_rec(pg, rec) {
  		failed = __ftrace_replace_code(rec, enable);
  		if (failed) {
  			ftrace_bug(failed, rec->ip);
  			/* Stop processing */
  			return;
  		}
  	} while_for_each_ftrace_rec();
  }
  
  struct ftrace_rec_iter {
  	struct ftrace_page	*pg;
  	int			index;
  };
  
  /**
   * ftrace_rec_iter_start, start up iterating over traced functions
   *
   * Returns an iterator handle that is used to iterate over all
   * the records that represent address locations where functions
   * are traced.
   *
   * May return NULL if no records are available.
   */
  struct ftrace_rec_iter *ftrace_rec_iter_start(void)
  {
  	/*
  	 * We only use a single iterator.
  	 * Protected by the ftrace_lock mutex.
  	 */
  	static struct ftrace_rec_iter ftrace_rec_iter;
  	struct ftrace_rec_iter *iter = &ftrace_rec_iter;
  
  	iter->pg = ftrace_pages_start;
  	iter->index = 0;
  
  	/* Could have empty pages */
  	while (iter->pg && !iter->pg->index)
  		iter->pg = iter->pg->next;
  
  	if (!iter->pg)
  		return NULL;
  
  	return iter;
  }
  
  /**
   * ftrace_rec_iter_next, get the next record to process.
   * @iter: The handle to the iterator.
   *
   * Returns the next iterator after the given iterator @iter.
   */
  struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
  {
  	iter->index++;
  
  	if (iter->index >= iter->pg->index) {
  		iter->pg = iter->pg->next;
  		iter->index = 0;
  
  		/* Could have empty pages */
  		while (iter->pg && !iter->pg->index)
  			iter->pg = iter->pg->next;
  	}
  
  	if (!iter->pg)
  		return NULL;
  
  	return iter;
  }
  
  /**
   * ftrace_rec_iter_record, get the record at the iterator location
   * @iter: The current iterator location
   *
   * Returns the record that the current @iter is at.
   */
  struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
  {
  	return &iter->pg->records[iter->index];
  }
  
  static int
  ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
  {
  	unsigned long ip;
  	int ret;
  
  	ip = rec->ip;
  
  	if (unlikely(ftrace_disabled))
  		return 0;
  
  	ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
  	if (ret) {
  		ftrace_bug(ret, ip);
  		return 0;
  	}
  	return 1;
  }
  
  /*
   * archs can override this function if they must do something
   * before the modifying code is performed.
   */
  int __weak ftrace_arch_code_modify_prepare(void)
  {
  	return 0;
  }
  
  /*
   * archs can override this function if they must do something
   * after the modifying code is performed.
   */
  int __weak ftrace_arch_code_modify_post_process(void)
  {
  	return 0;
  }
  
  void ftrace_modify_all_code(int command)
  {
  	int update = command & FTRACE_UPDATE_TRACE_FUNC;
  
  	/*
  	 * If the ftrace_caller calls a ftrace_ops func directly,
  	 * we need to make sure that it only traces functions it
  	 * expects to trace. When doing the switch of functions,
  	 * we need to update to the ftrace_ops_list_func first
  	 * before the transition between old and new calls are set,
  	 * as the ftrace_ops_list_func will check the ops hashes
  	 * to make sure the ops are having the right functions
  	 * traced.
  	 */
  	if (update)
  		ftrace_update_ftrace_func(ftrace_ops_list_func);
  
  	if (command & FTRACE_UPDATE_CALLS)
  		ftrace_replace_code(1);
  	else if (command & FTRACE_DISABLE_CALLS)
  		ftrace_replace_code(0);
  
  	if (update && ftrace_trace_function != ftrace_ops_list_func) {
  		function_trace_op = set_function_trace_op;
  		smp_wmb();
  		/* If irqs are disabled, we are in stop machine */
  		if (!irqs_disabled())
  			smp_call_function(ftrace_sync_ipi, NULL, 1);
  		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();
  }
  
  static int __ftrace_modify_code(void *data)
  {
  	int *command = data;
  
  	ftrace_modify_all_code(*command);
  
  	return 0;
  }
  
  /**
   * ftrace_run_stop_machine, go back to the stop machine method
   * @command: The command to tell ftrace what to do
   *
   * If an arch needs to fall back to the stop machine method, the
   * it can call this function.
   */
  void ftrace_run_stop_machine(int command)
  {
  	stop_machine(__ftrace_modify_code, &command, NULL);
  }
  
  /**
   * arch_ftrace_update_code, modify the code to trace or not trace
   * @command: The command that needs to be done
   *
   * Archs can override this function if it does not need to
   * run stop_machine() to modify code.
   */
  void __weak arch_ftrace_update_code(int command)
  {
  	ftrace_run_stop_machine(command);
  }
  
  static void ftrace_run_update_code(int command)
  {
  	int ret;
  
  	ret = ftrace_arch_code_modify_prepare();
  	FTRACE_WARN_ON(ret);
  	if (ret)
  		return;
  	/*
  	 * Do not call function tracer while we update the code.
  	 * We are in stop machine.
  	 */
  	function_trace_stop++;
  
  	/*
  	 * By default we use stop_machine() to modify the code.
  	 * But archs can do what ever they want as long as it
  	 * is safe. The stop_machine() is the safest, but also
  	 * produces the most overhead.
  	 */
  	arch_ftrace_update_code(command);
  
  	function_trace_stop--;
  
  	ret = ftrace_arch_code_modify_post_process();
  	FTRACE_WARN_ON(ret);
  }
  
  static ftrace_func_t saved_ftrace_func;
  static int ftrace_start_up;
  static int global_start_up;
  
  static void ftrace_startup_enable(int command)
  {
  	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 int ftrace_startup(struct ftrace_ops *ops, int command)
  {
  	bool hash_enable = true;
  	int ret;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	ret = __register_ftrace_function(ops);
  	if (ret)
  		return ret;
  
  	ftrace_start_up++;
  	command |= FTRACE_UPDATE_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 (hash_enable)
  		ftrace_hash_rec_enable(ops, 1);
  
  	ftrace_startup_enable(command);
  
  	return 0;
  }
  
  static int ftrace_shutdown(struct ftrace_ops *ops, int command)
  {
  	bool hash_disable = true;
  	int ret;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	ret = __unregister_ftrace_function(ops);
  	if (ret)
  		return ret;
  
  	ftrace_start_up--;
  	/*
  	 * Just warn in case of unbalance, no need to kill ftrace, it's not
  	 * critical but the ftrace_call callers may be never nopped again after
  	 * further ftrace uses.
  	 */
  	WARN_ON_ONCE(ftrace_start_up < 0);
  
  	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 (ops != &global_ops || !global_start_up)
  		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
  
  	command |= FTRACE_UPDATE_CALLS;
  
  	if (saved_ftrace_func != ftrace_trace_function) {
  		saved_ftrace_func = ftrace_trace_function;
  		command |= FTRACE_UPDATE_TRACE_FUNC;
  	}
  
  	if (!command || !ftrace_enabled) {
  		/*
  		 * If these are control ops, they still need their
  		 * per_cpu field freed. Since, function tracing is
  		 * not currently active, we can just free them
  		 * without synchronizing all CPUs.
  		 */
  		if (ops->flags & FTRACE_OPS_FL_CONTROL)
  			control_ops_free(ops);
  		return 0;
  	}
  
  	ftrace_run_update_code(command);
  
  	/*
  	 * Dynamic ops may be freed, we must make sure that all
  	 * callers are done before leaving this function.
  	 * The same goes for freeing the per_cpu data of the control
  	 * ops.
  	 *
  	 * Again, normal synchronize_sched() is not good enough.
  	 * We need to do a hard force of sched synchronization.
  	 * This is because we use preempt_disable() to do RCU, but
  	 * the function tracers can be called where RCU is not watching
  	 * (like before user_exit()). We can not rely on the RCU
  	 * infrastructure to do the synchronization, thus we must do it
  	 * ourselves.
  	 */
  	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
  		schedule_on_each_cpu(ftrace_sync);
  
  		if (ops->flags & FTRACE_OPS_FL_CONTROL)
  			control_ops_free(ops);
  	}
  
  	return 0;
  }
  
  static void ftrace_startup_sysctl(void)
  {
  	if (unlikely(ftrace_disabled))
  		return;
  
  	/* Force update next time */
  	saved_ftrace_func = NULL;
  	/* ftrace_start_up is true if we want ftrace running */
  	if (ftrace_start_up)
  		ftrace_run_update_code(FTRACE_UPDATE_CALLS);
  }
  
  static void ftrace_shutdown_sysctl(void)
  {
  	if (unlikely(ftrace_disabled))
  		return;
  
  	/* ftrace_start_up is true if ftrace is running */
  	if (ftrace_start_up)
  		ftrace_run_update_code(FTRACE_DISABLE_CALLS);
  }
  
  static cycle_t		ftrace_update_time;
  static unsigned long	ftrace_update_cnt;
  unsigned long		ftrace_update_tot_cnt;
  
  static inline int ops_traces_mod(struct ftrace_ops *ops)
  {
  	/*
  	 * Filter_hash being empty will default to trace module.
  	 * But notrace hash requires a test of individual module functions.
  	 */
  	return ftrace_hash_empty(ops->filter_hash) &&
  		ftrace_hash_empty(ops->notrace_hash);
  }
  
  /*
   * Check if the current ops references the record.
   *
   * If the ops traces all functions, then it was already accounted for.
   * If the ops does not trace the current record function, skip it.
   * If the ops ignores the function via notrace filter, skip it.
   */
  static inline bool
  ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
  {
  	/* If ops isn't enabled, ignore it */
  	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
  		return 0;
  
  	/* If ops traces all mods, we already accounted for it */
  	if (ops_traces_mod(ops))
  		return 0;
  
  	/* The function must be in the filter */
  	if (!ftrace_hash_empty(ops->filter_hash) &&
  	    !ftrace_lookup_ip(ops->filter_hash, rec->ip))
  		return 0;
  
  	/* If in notrace hash, we ignore it too */
  	if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
  		return 0;
  
  	return 1;
  }
  
  static int referenced_filters(struct dyn_ftrace *rec)
  {
  	struct ftrace_ops *ops;
  	int cnt = 0;
  
  	for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
  		if (ops_references_rec(ops, rec))
  		    cnt++;
  	}
  
  	return cnt;
  }
  
  static int ftrace_update_code(struct module *mod)
  {
  	struct ftrace_page *pg;
  	struct dyn_ftrace *p;
  	cycle_t start, stop;
  	unsigned long ref = 0;
  	bool test = false;
  	int i;
  
  	/*
  	 * When adding a module, we need to check if tracers are
  	 * currently enabled and if they are set to trace all functions.
  	 * If they are, we need to enable the module functions as well
  	 * as update the reference counts for those function records.
  	 */
  	if (mod) {
  		struct ftrace_ops *ops;
  
  		for (ops = ftrace_ops_list;
  		     ops != &ftrace_list_end; ops = ops->next) {
  			if (ops->flags & FTRACE_OPS_FL_ENABLED) {
  				if (ops_traces_mod(ops))
  					ref++;
  				else
  					test = true;
  			}
  		}
  	}
  
  	start = ftrace_now(raw_smp_processor_id());
  	ftrace_update_cnt = 0;
  
  	for (pg = ftrace_new_pgs; pg; pg = pg->next) {
  
  		for (i = 0; i < pg->index; i++) {
  			int cnt = ref;
  
  			/* If something went wrong, bail without enabling anything */
  			if (unlikely(ftrace_disabled))
  				return -1;
  
  			p = &pg->records[i];
  			if (test)
  				cnt += referenced_filters(p);
  			p->flags = cnt;
  
  			/*
  			 * Do the initial record conversion from mcount jump
  			 * to the NOP instructions.
  			 */
  			if (!ftrace_code_disable(mod, p))
  				break;
  
  			ftrace_update_cnt++;
  
  			/*
  			 * If the tracing is enabled, go ahead and enable the record.
  			 *
  			 * The reason not to enable the record immediatelly is the
  			 * inherent check of ftrace_make_nop/ftrace_make_call for
  			 * correct previous instructions.  Making first the NOP
  			 * conversion puts the module to the correct state, thus
  			 * passing the ftrace_make_call check.
  			 */
  			if (ftrace_start_up && cnt) {
  				int failed = __ftrace_replace_code(p, 1);
  				if (failed)
  					ftrace_bug(failed, p->ip);
  			}
  		}
  	}
  
  	ftrace_new_pgs = NULL;
  
  	stop = ftrace_now(raw_smp_processor_id());
  	ftrace_update_time = stop - start;
  	ftrace_update_tot_cnt += ftrace_update_cnt;
  
  	return 0;
  }
  
  static int ftrace_allocate_records(struct ftrace_page *pg, int count)
  {
  	int order;
  	int cnt;
  
  	if (WARN_ON(!count))
  		return -EINVAL;
  
  	order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
  
  	/*
  	 * We want to fill as much as possible. No more than a page
  	 * may be empty.
  	 */
  	while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
  		order--;
  
   again:
  	pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
  
  	if (!pg->records) {
  		/* if we can't allocate this size, try something smaller */
  		if (!order)
  			return -ENOMEM;
  		order >>= 1;
  		goto again;
  	}
  
  	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
  	pg->size = cnt;
  
  	if (cnt > count)
  		cnt = count;
  
  	return cnt;
  }
  
  static struct ftrace_page *
  ftrace_allocate_pages(unsigned long num_to_init)
  {
  	struct ftrace_page *start_pg;
  	struct ftrace_page *pg;
  	int order;
  	int cnt;
  
  	if (!num_to_init)
  		return 0;
  
  	start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
  	if (!pg)
  		return NULL;
  
  	/*
  	 * Try to allocate as much as possible in one continues
  	 * location that fills in all of the space. We want to
  	 * waste as little space as possible.
  	 */
  	for (;;) {
  		cnt = ftrace_allocate_records(pg, num_to_init);
  		if (cnt < 0)
  			goto free_pages;
  
  		num_to_init -= cnt;
  		if (!num_to_init)
  			break;
  
  		pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
  		if (!pg->next)
  			goto free_pages;
  
  		pg = pg->next;
  	}
  
  	return start_pg;
  
   free_pages:
  	while (start_pg) {
  		order = get_count_order(pg->size / ENTRIES_PER_PAGE);
  		free_pages((unsigned long)pg->records, order);
  		start_pg = pg->next;
  		kfree(pg);
  		pg = start_pg;
  	}
  	pr_info("ftrace: FAILED to allocate memory for functions\n");
  	return NULL;
  }
  
  static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
  {
  	int cnt;
  
  	if (!num_to_init) {
  		pr_info("ftrace: No functions to be traced?\n");
  		return -1;
  	}
  
  	cnt = num_to_init / ENTRIES_PER_PAGE;
  	pr_info("ftrace: allocating %ld entries in %d pages\n",
  		num_to_init, cnt + 1);
  
  	return 0;
  }
  
  #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
  
  struct ftrace_iterator {
  	loff_t				pos;
  	loff_t				func_pos;
  	struct ftrace_page		*pg;
  	struct dyn_ftrace		*func;
  	struct ftrace_func_probe	*probe;
  	struct trace_parser		parser;
  	struct ftrace_hash		*hash;
  	struct ftrace_ops		*ops;
  	int				hidx;
  	int				idx;
  	unsigned			flags;
  };
  
  static void *
  t_hash_next(struct seq_file *m, loff_t *pos)
  {
  	struct ftrace_iterator *iter = m->private;
  	struct hlist_node *hnd = NULL;
  	struct hlist_head *hhd;
  
  	(*pos)++;
  	iter->pos = *pos;
  
  	if (iter->probe)
  		hnd = &iter->probe->node;
   retry:
  	if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
  		return NULL;
  
  	hhd = &ftrace_func_hash[iter->hidx];
  
  	if (hlist_empty(hhd)) {
  		iter->hidx++;
  		hnd = NULL;
  		goto retry;
  	}
  
  	if (!hnd)
  		hnd = hhd->first;
  	else {
  		hnd = hnd->next;
  		if (!hnd) {
  			iter->hidx++;
  			goto retry;
  		}
  	}
  
  	if (WARN_ON_ONCE(!hnd))
  		return NULL;
  
  	iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
  
  	return iter;
  }
  
  static void *t_hash_start(struct seq_file *m, loff_t *pos)
  {
  	struct ftrace_iterator *iter = m->private;
  	void *p = NULL;
  	loff_t l;
  
  	if (!(iter->flags & FTRACE_ITER_DO_HASH))
  		return NULL;
  
  	if (iter->func_pos > *pos)
  		return NULL;
  
  	iter->hidx = 0;
  	for (l = 0; l <= (*pos - iter->func_pos); ) {
  		p = t_hash_next(m, &l);
  		if (!p)
  			break;
  	}
  	if (!p)
  		return NULL;
  
  	/* Only set this if we have an item */
  	iter->flags |= FTRACE_ITER_HASH;
  
  	return iter;
  }
  
  static int
  t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
  {
  	struct ftrace_func_probe *rec;
  
  	rec = iter->probe;
  	if (WARN_ON_ONCE(!rec))
  		return -EIO;
  
  	if (rec->ops->print)
  		return rec->ops->print(m, rec->ip, rec->ops, rec->data);
  
  	seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
  
  	if (rec->data)
  		seq_printf(m, ":%p", rec->data);
  	seq_putc(m, '\n');
  
  	return 0;
  }
  
  static void *
  t_next(struct seq_file *m, void *v, loff_t *pos)
  {
  	struct ftrace_iterator *iter = m->private;
  	struct ftrace_ops *ops = iter->ops;
  	struct dyn_ftrace *rec = NULL;
  
  	if (unlikely(ftrace_disabled))
  		return NULL;
  
  	if (iter->flags & FTRACE_ITER_HASH)
  		return t_hash_next(m, pos);
  
  	(*pos)++;
  	iter->pos = iter->func_pos = *pos;
  
  	if (iter->flags & FTRACE_ITER_PRINTALL)
  		return t_hash_start(m, pos);
  
   retry:
  	if (iter->idx >= iter->pg->index) {
  		if (iter->pg->next) {
  			iter->pg = iter->pg->next;
  			iter->idx = 0;
  			goto retry;
  		}
  	} else {
  		rec = &iter->pg->records[iter->idx++];
  		if (((iter->flags & FTRACE_ITER_FILTER) &&
  		     !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
  
  		    ((iter->flags & FTRACE_ITER_NOTRACE) &&
  		     !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
  
  		    ((iter->flags & FTRACE_ITER_ENABLED) &&
  		     !(rec->flags & FTRACE_FL_ENABLED))) {
  
  			rec = NULL;
  			goto retry;
  		}
  	}
  
  	if (!rec)
  		return t_hash_start(m, pos);
  
  	iter->func = rec;
  
  	return iter;
  }
  
  static void reset_iter_read(struct ftrace_iterator *iter)
  {
  	iter->pos = 0;
  	iter->func_pos = 0;
  	iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
  }
  
  static void *t_start(struct seq_file *m, loff_t *pos)
  {
  	struct ftrace_iterator *iter = m->private;
  	struct ftrace_ops *ops = iter->ops;
  	void *p = NULL;
  	loff_t l;
  
  	mutex_lock(&ftrace_lock);
  
  	if (unlikely(ftrace_disabled))
  		return NULL;
  
  	/*
  	 * If an lseek was done, then reset and start from beginning.
  	 */
  	if (*pos < iter->pos)
  		reset_iter_read(iter);
  
  	/*
  	 * For set_ftrace_filter reading, if we have the filter
  	 * off, we can short cut and just print out that all
  	 * functions are enabled.
  	 */
  	if (iter->flags & FTRACE_ITER_FILTER &&
  	    ftrace_hash_empty(ops->filter_hash)) {
  		if (*pos > 0)
  			return t_hash_start(m, pos);
  		iter->flags |= FTRACE_ITER_PRINTALL;
  		/* reset in case of seek/pread */
  		iter->flags &= ~FTRACE_ITER_HASH;
  		return iter;
  	}
  
  	if (iter->flags & FTRACE_ITER_HASH)
  		return t_hash_start(m, pos);
  
  	/*
  	 * Unfortunately, we need to restart at ftrace_pages_start
  	 * every time we let go of the ftrace_mutex. This is because
  	 * those pointers can change without the lock.
  	 */
  	iter->pg = ftrace_pages_start;
  	iter->idx = 0;
  	for (l = 0; l <= *pos; ) {
  		p = t_next(m, p, &l);
  		if (!p)
  			break;
  	}
  
  	if (!p)
  		return t_hash_start(m, pos);
  
  	return iter;
  }
  
  static void t_stop(struct seq_file *m, void *p)
  {
  	mutex_unlock(&ftrace_lock);
  }
  
  static int t_show(struct seq_file *m, void *v)
  {
  	struct ftrace_iterator *iter = m->private;
  	struct dyn_ftrace *rec;
  
  	if (iter->flags & FTRACE_ITER_HASH)
  		return t_hash_show(m, iter);
  
  	if (iter->flags & FTRACE_ITER_PRINTALL) {
  		seq_printf(m, "#### all functions enabled ####\n");
  		return 0;
  	}
  
  	rec = iter->func;
  
  	if (!rec)
  		return 0;
  
  	seq_printf(m, "%ps", (void *)rec->ip);
  	if (iter->flags & FTRACE_ITER_ENABLED)
  		seq_printf(m, " (%ld)%s",
  			   rec->flags & ~FTRACE_FL_MASK,
  			   rec->flags & FTRACE_FL_REGS ? " R" : "");
  	seq_printf(m, "\n");
  
  	return 0;
  }
  
  static const struct seq_operations show_ftrace_seq_ops = {
  	.start = t_start,
  	.next = t_next,
  	.stop = t_stop,
  	.show = t_show,
  };
  
  static int
  ftrace_avail_open(struct inode *inode, struct file *file)
  {
  	struct ftrace_iterator *iter;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
  	if (iter) {
  		iter->pg = ftrace_pages_start;
  		iter->ops = &global_ops;
  	}
  
  	return iter ? 0 : -ENOMEM;
  }
  
  static int
  ftrace_enabled_open(struct inode *inode, struct file *file)
  {
  	struct ftrace_iterator *iter;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
  	if (iter) {
  		iter->pg = ftrace_pages_start;
  		iter->flags = FTRACE_ITER_ENABLED;
  		iter->ops = &global_ops;
  	}
  
  	return iter ? 0 : -ENOMEM;
  }
  
  static void ftrace_filter_reset(struct ftrace_hash *hash)
  {
  	mutex_lock(&ftrace_lock);
  	ftrace_hash_clear(hash);
  	mutex_unlock(&ftrace_lock);
  }
  
  /**
   * ftrace_regex_open - initialize function tracer filter files
   * @ops: The ftrace_ops that hold the hash filters
   * @flag: The type of filter to process
   * @inode: The inode, usually passed in to your open routine
   * @file: The file, usually passed in to your open routine
   *
   * ftrace_regex_open() initializes the filter files for the
   * @ops. Depending on @flag it may process the filter hash or
   * the notrace hash of @ops. With this called from the open
   * routine, you can use ftrace_filter_write() for the write
   * routine if @flag has FTRACE_ITER_FILTER set, or
   * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
   * tracing_lseek() should be used as the lseek routine, and
   * release must call ftrace_regex_release().
   */
  int
  ftrace_regex_open(struct ftrace_ops *ops, int flag,
  		  struct inode *inode, struct file *file)
  {
  	struct ftrace_iterator *iter;
  	struct ftrace_hash *hash;
  	int ret = 0;
  
  	ftrace_ops_init(ops);
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
  	if (!iter)
  		return -ENOMEM;
  
  	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
  		kfree(iter);
  		return -ENOMEM;
  	}
  
  	iter->ops = ops;
  	iter->flags = flag;
  
  	mutex_lock(&ops->regex_lock);
  
  	if (flag & FTRACE_ITER_NOTRACE)
  		hash = ops->notrace_hash;
  	else
  		hash = ops->filter_hash;
  
  	if (file->f_mode & FMODE_WRITE) {
  		iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
  		if (!iter->hash) {
  			trace_parser_put(&iter->parser);
  			kfree(iter);
  			ret = -ENOMEM;
  			goto out_unlock;
  		}
  	}
  
  	if ((file->f_mode & FMODE_WRITE) &&
  	    (file->f_flags & O_TRUNC))
  		ftrace_filter_reset(iter->hash);
  
  	if (file->f_mode & FMODE_READ) {
  		iter->pg = ftrace_pages_start;
  
  		ret = seq_open(file, &show_ftrace_seq_ops);
  		if (!ret) {
  			struct seq_file *m = file->private_data;
  			m->private = iter;
  		} else {
  			/* Failed */
  			free_ftrace_hash(iter->hash);
  			trace_parser_put(&iter->parser);
  			kfree(iter);
  		}
  	} else
  		file->private_data = iter;
  
   out_unlock:
  	mutex_unlock(&ops->regex_lock);
  
  	return ret;
  }
  
  static int
  ftrace_filter_open(struct inode *inode, struct file *file)
  {
  	return ftrace_regex_open(&global_ops,
  			FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
  			inode, file);
  }
  
  static int
  ftrace_notrace_open(struct inode *inode, struct file *file)
  {
  	return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
  				 inode, file);
  }
  
  static int ftrace_match(char *str, char *regex, int len, int type)
  {
  	int matched = 0;
  	int slen;
  
  	switch (type) {
  	case MATCH_FULL:
  		if (strcmp(str, regex) == 0)
  			matched = 1;
  		break;
  	case MATCH_FRONT_ONLY:
  		if (strncmp(str, regex, len) == 0)
  			matched = 1;
  		break;
  	case MATCH_MIDDLE_ONLY:
  		if (strstr(str, regex))
  			matched = 1;
  		break;
  	case MATCH_END_ONLY:
  		slen = strlen(str);
  		if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
  			matched = 1;
  		break;
  	}
  
  	return matched;
  }
  
  static int
  enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
  {
  	struct ftrace_func_entry *entry;
  	int ret = 0;
  
  	entry = ftrace_lookup_ip(hash, rec->ip);
  	if (not) {
  		/* Do nothing if it doesn't exist */
  		if (!entry)
  			return 0;
  
  		free_hash_entry(hash, entry);
  	} else {
  		/* Do nothing if it exists */
  		if (entry)
  			return 0;
  
  		ret = add_hash_entry(hash, rec->ip);
  	}
  	return ret;
  }
  
  static int
  ftrace_match_record(struct dyn_ftrace *rec, char *mod,
  		    char *regex, int len, int type)
  {
  	char str[KSYM_SYMBOL_LEN];
  	char *modname;
  
  	kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
  
  	if (mod) {
  		/* module lookup requires matching the module */
  		if (!modname || strcmp(modname, mod))
  			return 0;
  
  		/* blank search means to match all funcs in the mod */
  		if (!len)
  			return 1;
  	}
  
  	return ftrace_match(str, regex, len, type);
  }
  
  static int
  match_records(struct ftrace_hash *hash, char *buff,
  	      int len, char *mod, int not)
  {
  	unsigned search_len = 0;
  	struct ftrace_page *pg;
  	struct dyn_ftrace *rec;
  	int type = MATCH_FULL;
  	char *search = buff;
  	int found = 0;
  	int ret;
  
  	if (len) {
  		type = filter_parse_regex(buff, len, &search, &not);
  		search_len = strlen(search);
  	}
  
  	mutex_lock(&ftrace_lock);
  
  	if (unlikely(ftrace_disabled))
  		goto out_unlock;
  
  	do_for_each_ftrace_rec(pg, rec) {
  		if (ftrace_match_record(rec, mod, search, search_len, type)) {
  			ret = enter_record(hash, rec, not);
  			if (ret < 0) {
  				found = ret;
  				goto out_unlock;
  			}
  			found = 1;
  		}
  	} while_for_each_ftrace_rec();
   out_unlock:
  	mutex_unlock(&ftrace_lock);
  
  	return found;
  }
  
  static int
  ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
  {
  	return match_records(hash, buff, len, NULL, 0);
  }
  
  static int
  ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
  {
  	int not = 0;
  
  	/* blank or '*' mean the same */
  	if (strcmp(buff, "*") == 0)
  		buff[0] = 0;
  
  	/* handle the case of 'dont filter this module' */
  	if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
  		buff[0] = 0;
  		not = 1;
  	}
  
  	return match_records(hash, buff, strlen(buff), mod, not);
  }
  
  /*
   * We register the module command as a template to show others how
   * to register the a command as well.
   */
  
  static int
  ftrace_mod_callback(struct ftrace_hash *hash,
  		    char *func, char *cmd, char *param, int enable)
  {
  	char *mod;
  	int ret = -EINVAL;
  
  	/*
  	 * cmd == 'mod' because we only registered this func
  	 * for the 'mod' ftrace_func_command.
  	 * But if you register one func with multiple commands,
  	 * you can tell which command was used by the cmd
  	 * parameter.
  	 */
  
  	/* we must have a module name */
  	if (!param)
  		return ret;
  
  	mod = strsep(&param, ":");
  	if (!strlen(mod))
  		return ret;
  
  	ret = ftrace_match_module_records(hash, func, mod);
  	if (!ret)
  		ret = -EINVAL;
  	if (ret < 0)
  		return ret;
  
  	return 0;
  }
  
  static struct ftrace_func_command ftrace_mod_cmd = {
  	.name			= "mod",
  	.func			= ftrace_mod_callback,
  };
  
  static int __init ftrace_mod_cmd_init(void)
  {
  	return register_ftrace_command(&ftrace_mod_cmd);
  }
  core_initcall(ftrace_mod_cmd_init);
  
  static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
  				      struct ftrace_ops *op, struct pt_regs *pt_regs)
  {
  	struct ftrace_func_probe *entry;
  	struct hlist_head *hhd;
  	unsigned long key;
  
  	key = hash_long(ip, FTRACE_HASH_BITS);
  
  	hhd = &ftrace_func_hash[key];
  
  	if (hlist_empty(hhd))
  		return;
  
  	/*
  	 * Disable preemption for these calls to prevent a RCU grace
  	 * period. This syncs the hash iteration and freeing of items
  	 * on the hash. rcu_read_lock is too dangerous here.
  	 */
  	preempt_disable_notrace();
  	hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
  		if (entry->ip == ip)
  			entry->ops->func(ip, parent_ip, &entry->data);
  	}
  	preempt_enable_notrace();
  }
  
  static struct ftrace_ops trace_probe_ops __read_mostly =
  {
  	.func		= function_trace_probe_call,
  	.flags		= FTRACE_OPS_FL_INITIALIZED,
  	INIT_REGEX_LOCK(trace_probe_ops)
  };
  
  static int ftrace_probe_registered;
  
  static void __enable_ftrace_function_probe(void)
  {
  	int ret;
  	int i;
  
  	if (ftrace_probe_registered) {
  		/* still need to update the function call sites */
  		if (ftrace_enabled)
  			ftrace_run_update_code(FTRACE_UPDATE_CALLS);
  		return;
  	}
  
  	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
  		struct hlist_head *hhd = &ftrace_func_hash[i];
  		if (hhd->first)
  			break;
  	}
  	/* Nothing registered? */
  	if (i == FTRACE_FUNC_HASHSIZE)
  		return;
  
  	ret = ftrace_startup(&trace_probe_ops, 0);
  
  	ftrace_probe_registered = 1;
  }
  
  static void __disable_ftrace_function_probe(void)
  {
  	int i;
  
  	if (!ftrace_probe_registered)
  		return;
  
  	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
  		struct hlist_head *hhd = &ftrace_func_hash[i];
  		if (hhd->first)
  			return;
  	}
  
  	/* no more funcs left */
  	ftrace_shutdown(&trace_probe_ops, 0);
  
  	ftrace_probe_registered = 0;
  }
  
  
  static void ftrace_free_entry(struct ftrace_func_probe *entry)
  {
  	if (entry->ops->free)
  		entry->ops->free(entry->ops, entry->ip, &entry->data);
  	kfree(entry);
  }
  
  int
  register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
  			      void *data)
  {
  	struct ftrace_func_probe *entry;
  	struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
  	struct ftrace_hash *hash;
  	struct ftrace_page *pg;
  	struct dyn_ftrace *rec;
  	int type, len, not;
  	unsigned long key;
  	int count = 0;
  	char *search;
  	int ret;
  
  	type = filter_parse_regex(glob, strlen(glob), &search, &not);
  	len = strlen(search);
  
  	/* we do not support '!' for function probes */
  	if (WARN_ON(not))
  		return -EINVAL;
  
  	mutex_lock(&trace_probe_ops.regex_lock);
  
  	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
  	if (!hash) {
  		count = -ENOMEM;
  		goto out;
  	}
  
  	if (unlikely(ftrace_disabled)) {
  		count = -ENODEV;
  		goto out;
  	}
  
  	mutex_lock(&ftrace_lock);
  
  	do_for_each_ftrace_rec(pg, rec) {
  
  		if (!ftrace_match_record(rec, NULL, search, len, type))
  			continue;
  
  		entry = kmalloc(sizeof(*entry), GFP_KERNEL);
  		if (!entry) {
  			/* If we did not process any, then return error */
  			if (!count)
  				count = -ENOMEM;
  			goto out_unlock;
  		}
  
  		count++;
  
  		entry->data = data;
  
  		/*
  		 * The caller might want to do something special
  		 * for each function we find. We call the callback
  		 * to give the caller an opportunity to do so.
  		 */
  		if (ops->init) {
  			if (ops->init(ops, rec->ip, &entry->data) < 0) {
  				/* caller does not like this func */
  				kfree(entry);
  				continue;
  			}
  		}
  
  		ret = enter_record(hash, rec, 0);
  		if (ret < 0) {
  			kfree(entry);
  			count = ret;
  			goto out_unlock;
  		}
  
  		entry->ops = ops;
  		entry->ip = rec->ip;
  
  		key = hash_long(entry->ip, FTRACE_HASH_BITS);
  		hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
  
  	} while_for_each_ftrace_rec();
  
  	ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
  	if (ret < 0)
  		count = ret;
  
  	__enable_ftrace_function_probe();
  
   out_unlock:
  	mutex_unlock(&ftrace_lock);
   out:
  	mutex_unlock(&trace_probe_ops.regex_lock);
  	free_ftrace_hash(hash);
  
  	return count;
  }
  
  enum {
  	PROBE_TEST_FUNC		= 1,
  	PROBE_TEST_DATA		= 2
  };
  
  static void
  __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
  				  void *data, int flags)
  {
  	struct ftrace_func_entry *rec_entry;
  	struct ftrace_func_probe *entry;
  	struct ftrace_func_probe *p;
  	struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
  	struct list_head free_list;
  	struct ftrace_hash *hash;
  	struct hlist_node *tmp;
  	char str[KSYM_SYMBOL_LEN];
  	int type = MATCH_FULL;
  	int i, len = 0;
  	char *search;
  
  	if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
  		glob = NULL;
  	else if (glob) {
  		int not;
  
  		type = filter_parse_regex(glob, strlen(glob), &search, &not);
  		len = strlen(search);
  
  		/* we do not support '!' for function probes */
  		if (WARN_ON(not))
  			return;
  	}
  
  	mutex_lock(&trace_probe_ops.regex_lock);
  
  	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
  	if (!hash)
  		/* Hmm, should report this somehow */
  		goto out_unlock;
  
  	INIT_LIST_HEAD(&free_list);
  
  	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
  		struct hlist_head *hhd = &ftrace_func_hash[i];
  
  		hlist_for_each_entry_safe(entry, tmp, hhd, node) {
  
  			/* break up if statements for readability */
  			if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
  				continue;
  
  			if ((flags & PROBE_TEST_DATA) && entry->data != data)
  				continue;
  
  			/* do this last, since it is the most expensive */
  			if (glob) {
  				kallsyms_lookup(entry->ip, NULL, NULL,
  						NULL, str);
  				if (!ftrace_match(str, glob, len, type))
  					continue;
  			}
  
  			rec_entry = ftrace_lookup_ip(hash, entry->ip);
  			/* It is possible more than one entry had this ip */
  			if (rec_entry)
  				free_hash_entry(hash, rec_entry);
  
  			hlist_del_rcu(&entry->node);
  			list_add(&entry->free_list, &free_list);
  		}
  	}
  	mutex_lock(&ftrace_lock);
  	__disable_ftrace_function_probe();
  	/*
  	 * Remove after the disable is called. Otherwise, if the last
  	 * probe is removed, a null hash means *all enabled*.
  	 */
  	ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
  	synchronize_sched();
  	list_for_each_entry_safe(entry, p, &free_list, free_list) {
  		list_del(&entry->free_list);
  		ftrace_free_entry(entry);
  	}
  	mutex_unlock(&ftrace_lock);
  		
   out_unlock:
  	mutex_unlock(&trace_probe_ops.regex_lock);
  	free_ftrace_hash(hash);
  }
  
  void
  unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
  				void *data)
  {
  	__unregister_ftrace_function_probe(glob, ops, data,
  					  PROBE_TEST_FUNC | PROBE_TEST_DATA);
  }
  
  void
  unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
  {
  	__unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
  }
  
  void unregister_ftrace_function_probe_all(char *glob)
  {
  	__unregister_ftrace_function_probe(glob, NULL, NULL, 0);
  }
  
  static LIST_HEAD(ftrace_commands);
  static DEFINE_MUTEX(ftrace_cmd_mutex);
  
  /*
   * Currently we only register ftrace commands from __init, so mark this
   * __init too.
   */
  __init int register_ftrace_command(struct ftrace_func_command *cmd)
  {
  	struct ftrace_func_command *p;
  	int ret = 0;
  
  	mutex_lock(&ftrace_cmd_mutex);
  	list_for_each_entry(p, &ftrace_commands, list) {
  		if (strcmp(cmd->name, p->name) == 0) {
  			ret = -EBUSY;
  			goto out_unlock;
  		}
  	}
  	list_add(&cmd->list, &ftrace_commands);
   out_unlock:
  	mutex_unlock(&ftrace_cmd_mutex);
  
  	return ret;
  }
  
  /*
   * Currently we only unregister ftrace commands from __init, so mark
   * this __init too.
   */
  __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
  {
  	struct ftrace_func_command *p, *n;
  	int ret = -ENODEV;
  
  	mutex_lock(&ftrace_cmd_mutex);
  	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
  		if (strcmp(cmd->name, p->name) == 0) {
  			ret = 0;
  			list_del_init(&p->list);
  			goto out_unlock;
  		}
  	}
   out_unlock:
  	mutex_unlock(&ftrace_cmd_mutex);
  
  	return ret;
  }
  
  static int ftrace_process_regex(struct ftrace_hash *hash,
  				char *buff, int len, int enable)
  {
  	char *func, *command, *next = buff;
  	struct ftrace_func_command *p;
  	int ret = -EINVAL;
  
  	func = strsep(&next, ":");
  
  	if (!next) {
  		ret = ftrace_match_records(hash, func, len);
  		if (!ret)
  			ret = -EINVAL;
  		if (ret < 0)
  			return ret;
  		return 0;
  	}
  
  	/* command found */
  
  	command = strsep(&next, ":");
  
  	mutex_lock(&ftrace_cmd_mutex);
  	list_for_each_entry(p, &ftrace_commands, list) {
  		if (strcmp(p->name, command) == 0) {
  			ret = p->func(hash, func, command, next, enable);
  			goto out_unlock;
  		}
  	}
   out_unlock:
  	mutex_unlock(&ftrace_cmd_mutex);
  
  	return ret;
  }
  
  static ssize_t
  ftrace_regex_write(struct file *file, const char __user *ubuf,
  		   size_t cnt, loff_t *ppos, int enable)
  {
  	struct ftrace_iterator *iter;
  	struct trace_parser *parser;
  	ssize_t ret, read;
  
  	if (!cnt)
  		return 0;
  
  	if (file->f_mode & FMODE_READ) {
  		struct seq_file *m = file->private_data;
  		iter = m->private;
  	} else
  		iter = file->private_data;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	/* iter->hash is a local copy, so we don't need regex_lock */
  
  	parser = &iter->parser;
  	read = trace_get_user(parser, ubuf, cnt, ppos);
  
  	if (read >= 0 && trace_parser_loaded(parser) &&
  	    !trace_parser_cont(parser)) {
  		ret = ftrace_process_regex(iter->hash, parser->buffer,
  					   parser->idx, enable);
  		trace_parser_clear(parser);
  		if (ret < 0)
  			goto out;
  	}
  
  	ret = read;
   out:
  	return ret;
  }
  
  ssize_t
  ftrace_filter_write(struct file *file, const char __user *ubuf,
  		    size_t cnt, loff_t *ppos)
  {
  	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
  }
  
  ssize_t
  ftrace_notrace_write(struct file *file, const char __user *ubuf,
  		     size_t cnt, loff_t *ppos)
  {
  	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
  }
  
  static int
  ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
  {
  	struct ftrace_func_entry *entry;
  
  	if (!ftrace_location(ip))
  		return -EINVAL;
  
  	if (remove) {
  		entry = ftrace_lookup_ip(hash, ip);
  		if (!entry)
  			return -ENOENT;
  		free_hash_entry(hash, entry);
  		return 0;
  	}
  
  	return add_hash_entry(hash, ip);
  }
  
  static void ftrace_ops_update_code(struct ftrace_ops *ops)
  {
  	if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
  		ftrace_run_update_code(FTRACE_UPDATE_CALLS);
  }
  
  static int
  ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
  		unsigned long ip, int remove, int reset, int enable)
  {
  	struct ftrace_hash **orig_hash;
  	struct ftrace_hash *hash;
  	int ret;
  
  	/* All global ops uses the global ops filters */
  	if (ops->flags & FTRACE_OPS_FL_GLOBAL)
  		ops = &global_ops;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	mutex_lock(&ops->regex_lock);
  
  	if (enable)
  		orig_hash = &ops->filter_hash;
  	else
  		orig_hash = &ops->notrace_hash;
  
  	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
  	if (!hash) {
  		ret = -ENOMEM;
  		goto out_regex_unlock;
  	}
  
  	if (reset)
  		ftrace_filter_reset(hash);
  	if (buf && !ftrace_match_records(hash, buf, len)) {
  		ret = -EINVAL;
  		goto out_regex_unlock;
  	}
  	if (ip) {
  		ret = ftrace_match_addr(hash, ip, remove);
  		if (ret < 0)
  			goto out_regex_unlock;
  	}
  
  	mutex_lock(&ftrace_lock);
  	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
  	if (!ret)
  		ftrace_ops_update_code(ops);
  
  	mutex_unlock(&ftrace_lock);
  
   out_regex_unlock:
  	mutex_unlock(&ops->regex_lock);
  
  	free_ftrace_hash(hash);
  	return ret;
  }
  
  static int
  ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
  		int reset, int enable)
  {
  	return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
  }
  
  /**
   * ftrace_set_filter_ip - set a function to filter on in ftrace by address
   * @ops - the ops to set the filter with
   * @ip - the address to add to or remove from the filter.
   * @remove - non zero to remove the ip from the filter
   * @reset - non zero to reset all filters before applying this filter.
   *
   * Filters denote which functions should be enabled when tracing is enabled
   * If @ip is NULL, it failes to update filter.
   */
  int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
  			 int remove, int reset)
  {
  	ftrace_ops_init(ops);
  	return ftrace_set_addr(ops, ip, remove, reset, 1);
  }
  EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
  
  static int
  ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
  		 int reset, int enable)
  {
  	return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
  }
  
  /**
   * ftrace_set_filter - set a function to filter on in ftrace
   * @ops - the ops to set the filter with
   * @buf - the string that holds the function filter text.
   * @len - the length of the string.
   * @reset - non zero to reset all filters before applying this filter.
   *
   * Filters denote which functions should be enabled when tracing is enabled.
   * If @buf is NULL and reset is set, all functions will be enabled for tracing.
   */
  int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
  		       int len, int reset)
  {
  	ftrace_ops_init(ops);
  	return ftrace_set_regex(ops, buf, len, reset, 1);
  }
  EXPORT_SYMBOL_GPL(ftrace_set_filter);
  
  /**
   * ftrace_set_notrace - set a function to not trace in ftrace
   * @ops - the ops to set the notrace filter with
   * @buf - the string that holds the function notrace text.
   * @len - the length of the string.
   * @reset - non zero to reset all filters before applying this filter.
   *
   * Notrace Filters denote which functions should not be enabled when tracing
   * is enabled. If @buf is NULL and reset is set, all functions will be enabled
   * for tracing.
   */
  int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
  			int len, int reset)
  {
  	ftrace_ops_init(ops);
  	return ftrace_set_regex(ops, buf, len, reset, 0);
  }
  EXPORT_SYMBOL_GPL(ftrace_set_notrace);
  /**
   * ftrace_set_filter - set a function to filter on in ftrace
   * @ops - the ops to set the filter with
   * @buf - the string that holds the function filter text.
   * @len - the length of the string.
   * @reset - non zero to reset all filters before applying this filter.
   *
   * Filters denote which functions should be enabled when tracing is enabled.
   * If @buf is NULL and reset is set, all functions will be enabled for tracing.
   */
  void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
  {
  	ftrace_set_regex(&global_ops, buf, len, reset, 1);
  }
  EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
  
  /**
   * ftrace_set_notrace - set a function to not trace in ftrace
   * @ops - the ops to set the notrace filter with
   * @buf - the string that holds the function notrace text.
   * @len - the length of the string.
   * @reset - non zero to reset all filters before applying this filter.
   *
   * Notrace Filters denote which functions should not be enabled when tracing
   * is enabled. If @buf is NULL and reset is set, all functions will be enabled
   * for tracing.
   */
  void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
  {
  	ftrace_set_regex(&global_ops, buf, len, reset, 0);
  }
  EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
  
  /*
   * command line interface to allow users to set filters on boot up.
   */
  #define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
  static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
  static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
  
  /* Used by function selftest to not test if filter is set */
  bool ftrace_filter_param __initdata;
  
  static int __init set_ftrace_notrace(char *str)
  {
  	ftrace_filter_param = true;
  	strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
  	return 1;
  }
  __setup("ftrace_notrace=", set_ftrace_notrace);
  
  static int __init set_ftrace_filter(char *str)
  {
  	ftrace_filter_param = true;
  	strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
  	return 1;
  }
  __setup("ftrace_filter=", set_ftrace_filter);
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
  static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
  
  static int __init set_graph_function(char *str)
  {
  	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
  	return 1;
  }
  __setup("ftrace_graph_filter=", set_graph_function);
  
  static void __init set_ftrace_early_graph(char *buf)
  {
  	int ret;
  	char *func;
  
  	while (buf) {
  		func = strsep(&buf, ",");
  		/* we allow only one expression at a time */
  		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
  				      FTRACE_GRAPH_MAX_FUNCS, func);
  		if (ret)
  			printk(KERN_DEBUG "ftrace: function %s not "
  					  "traceable\n", func);
  	}
  }
  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  
  void __init
  ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
  {
  	char *func;
  
  	ftrace_ops_init(ops);
  
  	while (buf) {
  		func = strsep(&buf, ",");
  		ftrace_set_regex(ops, func, strlen(func), 0, enable);
  	}
  }
  
  static void __init set_ftrace_early_filters(void)
  {
  	if (ftrace_filter_buf[0])
  		ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
  	if (ftrace_notrace_buf[0])
  		ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  	if (ftrace_graph_buf[0])
  		set_ftrace_early_graph(ftrace_graph_buf);
  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  }
  
  int ftrace_regex_release(struct inode *inode, struct file *file)
  {
  	struct seq_file *m = (struct seq_file *)file->private_data;
  	struct ftrace_iterator *iter;
  	struct ftrace_hash **orig_hash;
  	struct trace_parser *parser;
  	int filter_hash;
  	int ret;
  
  	if (file->f_mode & FMODE_READ) {
  		iter = m->private;
  		seq_release(inode, file);
  	} else
  		iter = file->private_data;
  
  	parser = &iter->parser;
  	if (trace_parser_loaded(parser)) {
  		parser->buffer[parser->idx] = 0;
  		ftrace_match_records(iter->hash, parser->buffer, parser->idx);
  	}
  
  	trace_parser_put(parser);
  
  	mutex_lock(&iter->ops->regex_lock);
  
  	if (file->f_mode & FMODE_WRITE) {
  		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
  
  		if (filter_hash)
  			orig_hash = &iter->ops->filter_hash;
  		else
  			orig_hash = &iter->ops->notrace_hash;
  
  		mutex_lock(&ftrace_lock);
  		ret = ftrace_hash_move(iter->ops, filter_hash,
  				       orig_hash, iter->hash);
  		if (!ret)
  			ftrace_ops_update_code(iter->ops);
  
  		mutex_unlock(&ftrace_lock);
  	}
  
  	mutex_unlock(&iter->ops->regex_lock);
  	free_ftrace_hash(iter->hash);
  	kfree(iter);
  
  	return 0;
  }
  
  static const struct file_operations ftrace_avail_fops = {
  	.open = ftrace_avail_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = seq_release_private,
  };
  
  static const struct file_operations ftrace_enabled_fops = {
  	.open = ftrace_enabled_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = seq_release_private,
  };
  
  static const struct file_operations ftrace_filter_fops = {
  	.open = ftrace_filter_open,
  	.read = seq_read,
  	.write = ftrace_filter_write,
  	.llseek = tracing_lseek,
  	.release = ftrace_regex_release,
  };
  
  static const struct file_operations ftrace_notrace_fops = {
  	.open = ftrace_notrace_open,
  	.read = seq_read,
  	.write = ftrace_notrace_write,
  	.llseek = tracing_lseek,
  	.release = ftrace_regex_release,
  };
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  
  static DEFINE_MUTEX(graph_lock);
  
  int ftrace_graph_count;
  int ftrace_graph_notrace_count;
  unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
  unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
  
  struct ftrace_graph_data {
  	unsigned long *table;
  	size_t size;
  	int *count;
  	const struct seq_operations *seq_ops;
  };
  
  static void *
  __g_next(struct seq_file *m, loff_t *pos)
  {
  	struct ftrace_graph_data *fgd = m->private;
  
  	if (*pos >= *fgd->count)
  		return NULL;
  	return &fgd->table[*pos];
  }
  
  static void *
  g_next(struct seq_file *m, void *v, loff_t *pos)
  {
  	(*pos)++;
  	return __g_next(m, pos);
  }
  
  static void *g_start(struct seq_file *m, loff_t *pos)
  {
  	struct ftrace_graph_data *fgd = m->private;
  
  	mutex_lock(&graph_lock);
  
  	/* Nothing, tell g_show to print all functions are enabled */
  	if (!*fgd->count && !*pos)
  		return (void *)1;
  
  	return __g_next(m, pos);
  }
  
  static void g_stop(struct seq_file *m, void *p)
  {
  	mutex_unlock(&graph_lock);
  }
  
  static int g_show(struct seq_file *m, void *v)
  {
  	unsigned long *ptr = v;
  
  	if (!ptr)
  		return 0;
  
  	if (ptr == (unsigned long *)1) {
  		seq_printf(m, "#### all functions enabled ####\n");
  		return 0;
  	}
  
  	seq_printf(m, "%ps\n", (void *)*ptr);
  
  	return 0;
  }
  
  static const struct seq_operations ftrace_graph_seq_ops = {
  	.start = g_start,
  	.next = g_next,
  	.stop = g_stop,
  	.show = g_show,
  };
  
  static int
  __ftrace_graph_open(struct inode *inode, struct file *file,
  		    struct ftrace_graph_data *fgd)
  {
  	int ret = 0;
  
  	mutex_lock(&graph_lock);
  	if ((file->f_mode & FMODE_WRITE) &&
  	    (file->f_flags & O_TRUNC)) {
  		*fgd->count = 0;
  		memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
  	}
  	mutex_unlock(&graph_lock);
  
  	if (file->f_mode & FMODE_READ) {
  		ret = seq_open(file, fgd->seq_ops);
  		if (!ret) {
  			struct seq_file *m = file->private_data;
  			m->private = fgd;
  		}
  	} else
  		file->private_data = fgd;
  
  	return ret;
  }
  
  static int
  ftrace_graph_open(struct inode *inode, struct file *file)
  {
  	struct ftrace_graph_data *fgd;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
  	if (fgd == NULL)
  		return -ENOMEM;
  
  	fgd->table = ftrace_graph_funcs;
  	fgd->size = FTRACE_GRAPH_MAX_FUNCS;
  	fgd->count = &ftrace_graph_count;
  	fgd->seq_ops = &ftrace_graph_seq_ops;
  
  	return __ftrace_graph_open(inode, file, fgd);
  }
  
  static int
  ftrace_graph_notrace_open(struct inode *inode, struct file *file)
  {
  	struct ftrace_graph_data *fgd;
  
  	if (unlikely(ftrace_disabled))
  		return -ENODEV;
  
  	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
  	if (fgd == NULL)
  		return -ENOMEM;
  
  	fgd->table = ftrace_graph_notrace_funcs;
  	fgd->size = FTRACE_GRAPH_MAX_FUNCS;
  	fgd->count = &ftrace_graph_notrace_count;
  	fgd->seq_ops = &ftrace_graph_seq_ops;
  
  	return __ftrace_graph_open(inode, file, fgd);
  }
  
  static int
  ftrace_graph_release(struct inode *inode, struct file *file)
  {
  	if (file->f_mode & FMODE_READ) {
  		struct seq_file *m = file->private_data;
  
  		kfree(m->private);
  		seq_release(inode, file);
  	} else {
  		kfree(file->private_data);
  	}
  
  	return 0;
  }
  
  static int
  ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
  {
  	struct dyn_ftrace *rec;
  	struct ftrace_page *pg;
  	int search_len;
  	int fail = 1;
  	int type, not;
  	char *search;
  	bool exists;
  	int i;
  
  	/* decode regex */
  	type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
  	if (!not && *idx >= size)
  		return -EBUSY;
  
  	search_len = strlen(search);
  
  	mutex_lock(&ftrace_lock);
  
  	if (unlikely(ftrace_disabled)) {
  		mutex_unlock(&ftrace_lock);
  		return -ENODEV;
  	}
  
  	do_for_each_ftrace_rec(pg, rec) {
  
  		if (ftrace_match_record(rec, NULL, search, search_len, type)) {
  			/* if it is in the array */
  			exists = false;
  			for (i = 0; i < *idx; i++) {
  				if (array[i] == rec->ip) {
  					exists = true;
  					break;
  				}
  			}
  
  			if (!not) {
  				fail = 0;
  				if (!exists) {
  					array[(*idx)++] = rec->ip;
  					if (*idx >= size)
  						goto out;
  				}
  			} else {
  				if (exists) {
  					array[i] = array[--(*idx)];
  					array[*idx] = 0;
  					fail = 0;
  				}
  			}
  		}
  	} while_for_each_ftrace_rec();
  out:
  	mutex_unlock(&ftrace_lock);
  
  	if (fail)
  		return -EINVAL;
  
  	return 0;
  }
  
  static ssize_t
  ftrace_graph_write(struct file *file, const char __user *ubuf,
  		   size_t cnt, loff_t *ppos)
  {
  	struct trace_parser parser;
  	ssize_t read, ret = 0;
  	struct ftrace_graph_data *fgd = file->private_data;
  
  	if (!cnt)
  		return 0;
  
  	if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
  		return -ENOMEM;
  
  	read = trace_get_user(&parser, ubuf, cnt, ppos);
  
  	if (read >= 0 && trace_parser_loaded((&parser))) {
  		parser.buffer[parser.idx] = 0;
  
  		mutex_lock(&graph_lock);
  
  		/* we allow only one expression at a time */
  		ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
  				      parser.buffer);
  
  		mutex_unlock(&graph_lock);
  	}
  
  	if (!ret)
  		ret = read;
  
  	trace_parser_put(&parser);
  
  	return ret;
  }
  
  static const struct file_operations ftrace_graph_fops = {
  	.open		= ftrace_graph_open,
  	.read		= seq_read,
  	.write		= ftrace_graph_write,
  	.llseek		= tracing_lseek,
  	.release	= ftrace_graph_release,
  };
  
  static const struct file_operations ftrace_graph_notrace_fops = {
  	.open		= ftrace_graph_notrace_open,
  	.read		= seq_read,
  	.write		= ftrace_graph_write,
  	.llseek		= tracing_lseek,
  	.release	= ftrace_graph_release,
  };
  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  
  static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
  {
  
  	trace_create_file("available_filter_functions", 0444,
  			d_tracer, NULL, &ftrace_avail_fops);
  
  	trace_create_file("enabled_functions", 0444,
  			d_tracer, NULL, &ftrace_enabled_fops);
  
  	trace_create_file("set_ftrace_filter", 0644, d_tracer,
  			NULL, &ftrace_filter_fops);
  
  	trace_create_file("set_ftrace_notrace", 0644, d_tracer,
  				    NULL, &ftrace_notrace_fops);
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  	trace_create_file("set_graph_function", 0444, d_tracer,
  				    NULL,
  				    &ftrace_graph_fops);
  	trace_create_file("set_graph_notrace", 0444, d_tracer,
  				    NULL,
  				    &ftrace_graph_notrace_fops);
  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  
  	return 0;
  }
  
  static int ftrace_cmp_ips(const void *a, const void *b)
  {
  	const unsigned long *ipa = a;
  	const unsigned long *ipb = b;
  
  	if (*ipa > *ipb)
  		return 1;
  	if (*ipa < *ipb)
  		return -1;
  	return 0;
  }
  
  static void ftrace_swap_ips(void *a, void *b, int size)
  {
  	unsigned long *ipa = a;
  	unsigned long *ipb = b;
  	unsigned long t;
  
  	t = *ipa;
  	*ipa = *ipb;
  	*ipb = t;
  }
  
  static int ftrace_process_locs(struct module *mod,
  			       unsigned long *start,
  			       unsigned long *end)
  {
  	struct ftrace_page *start_pg;
  	struct ftrace_page *pg;
  	struct dyn_ftrace *rec;
  	unsigned long count;
  	unsigned long *p;
  	unsigned long addr;
  	unsigned long flags = 0; /* Shut up gcc */
  	int ret = -ENOMEM;
  
  	count = end - start;
  
  	if (!count)
  		return 0;
  
  	sort(start, count, sizeof(*start),
  	     ftrace_cmp_ips, ftrace_swap_ips);
  
  	start_pg = ftrace_allocate_pages(count);
  	if (!start_pg)
  		return -ENOMEM;
  
  	mutex_lock(&ftrace_lock);
  
  	/*
  	 * Core and each module needs their own pages, as
  	 * modules will free them when they are removed.
  	 * Force a new page to be allocated for modules.
  	 */
  	if (!mod) {
  		WARN_ON(ftrace_pages || ftrace_pages_start);
  		/* First initialization */
  		ftrace_pages = ftrace_pages_start = start_pg;
  	} else {
  		if (!ftrace_pages)
  			goto out;
  
  		if (WARN_ON(ftrace_pages->next)) {
  			/* Hmm, we have free pages? */
  			while (ftrace_pages->next)
  				ftrace_pages = ftrace_pages->next;
  		}
  
  		ftrace_pages->next = start_pg;
  	}
  
  	p = start;
  	pg = start_pg;
  	while (p < end) {
  		addr = ftrace_call_adjust(*p++);
  		/*
  		 * Some architecture linkers will pad between
  		 * the different mcount_loc sections of different
  		 * object files to satisfy alignments.
  		 * Skip any NULL pointers.
  		 */
  		if (!addr)
  			continue;
  
  		if (pg->index == pg->size) {
  			/* We should have allocated enough */
  			if (WARN_ON(!pg->next))
  				break;
  			pg = pg->next;
  		}
  
  		rec = &pg->records[pg->index++];
  		rec->ip = addr;
  	}
  
  	/* We should have used all pages */
  	WARN_ON(pg->next);
  
  	/* Assign the last page to ftrace_pages */
  	ftrace_pages = pg;
  
  	/* These new locations need to be initialized */
  	ftrace_new_pgs = start_pg;
  
  	/*
  	 * We only need to disable interrupts on start up
  	 * because we are modifying code that an interrupt
  	 * may execute, and the modification is not atomic.
  	 * But for modules, nothing runs the code we modify
  	 * until we are finished with it, and there's no
  	 * reason to cause large interrupt latencies while we do it.
  	 */
  	if (!mod)
  		local_irq_save(flags);
  	ftrace_update_code(mod);
  	if (!mod)
  		local_irq_restore(flags);
  	ret = 0;
   out:
  	mutex_unlock(&ftrace_lock);
  
  	return ret;
  }
  
  #ifdef CONFIG_MODULES
  
  #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
  
  void ftrace_release_mod(struct module *mod)
  {
  	struct dyn_ftrace *rec;
  	struct ftrace_page **last_pg;
  	struct ftrace_page *pg;
  	int order;
  
  	mutex_lock(&ftrace_lock);
  
  	if (ftrace_disabled)
  		goto out_unlock;
  
  	/*
  	 * Each module has its own ftrace_pages, remove
  	 * them from the list.
  	 */
  	last_pg = &ftrace_pages_start;
  	for (pg = ftrace_pages_start; pg; pg = *last_pg) {
  		rec = &pg->records[0];
  		if (within_module_core(rec->ip, mod)) {
  			/*
  			 * As core pages are first, the first
  			 * page should never be a module page.
  			 */
  			if (WARN_ON(pg == ftrace_pages_start))
  				goto out_unlock;
  
  			/* Check if we are deleting the last page */
  			if (pg == ftrace_pages)
  				ftrace_pages = next_to_ftrace_page(last_pg);
  
  			*last_pg = pg->next;
  			order = get_count_order(pg->size / ENTRIES_PER_PAGE);
  			free_pages((unsigned long)pg->records, order);
  			kfree(pg);
  		} else
  			last_pg = &pg->next;
  	}
   out_unlock:
  	mutex_unlock(&ftrace_lock);
  }
  
  static void ftrace_init_module(struct module *mod,
  			       unsigned long *start, unsigned long *end)
  {
  	if (ftrace_disabled || start == end)
  		return;
  	ftrace_process_locs(mod, start, end);
  }
  
  static int ftrace_module_notify_enter(struct notifier_block *self,
  				      unsigned long val, void *data)
  {
  	struct module *mod = data;
  
  	if (val == MODULE_STATE_COMING)
  		ftrace_init_module(mod, mod->ftrace_callsites,
  				   mod->ftrace_callsites +
  				   mod->num_ftrace_callsites);
  	return 0;
  }
  
  static int ftrace_module_notify_exit(struct notifier_block *self,
  				     unsigned long val, void *data)
  {
  	struct module *mod = data;
  
  	if (val == MODULE_STATE_GOING)
  		ftrace_release_mod(mod);
  
  	return 0;
  }
  #else
  static int ftrace_module_notify_enter(struct notifier_block *self,
  				      unsigned long val, void *data)
  {
  	return 0;
  }
  static int ftrace_module_notify_exit(struct notifier_block *self,
  				     unsigned long val, void *data)
  {
  	return 0;
  }
  #endif /* CONFIG_MODULES */
  
  struct notifier_block ftrace_module_enter_nb = {
  	.notifier_call = ftrace_module_notify_enter,
  	.priority = INT_MAX,	/* Run before anything that can use kprobes */
  };
  
  struct notifier_block ftrace_module_exit_nb = {
  	.notifier_call = ftrace_module_notify_exit,
  	.priority = INT_MIN,	/* Run after anything that can remove kprobes */
  };
  
  extern unsigned long __start_mcount_loc[];
  extern unsigned long __stop_mcount_loc[];
  
  void __init ftrace_init(void)
  {
  	unsigned long count, addr, flags;
  	int ret;
  
  	/* Keep the ftrace pointer to the stub */
  	addr = (unsigned long)ftrace_stub;
  
  	local_irq_save(flags);
  	ftrace_dyn_arch_init(&addr);
  	local_irq_restore(flags);
  
  	/* ftrace_dyn_arch_init places the return code in addr */
  	if (addr)
  		goto failed;
  
  	count = __stop_mcount_loc - __start_mcount_loc;
  
  	ret = ftrace_dyn_table_alloc(count);
  	if (ret)
  		goto failed;
  
  	last_ftrace_enabled = ftrace_enabled = 1;
  
  	ret = ftrace_process_locs(NULL,
  				  __start_mcount_loc,
  				  __stop_mcount_loc);
  
  	ret = register_module_notifier(&ftrace_module_enter_nb);
  	if (ret)
  		pr_warning("Failed to register trace ftrace module enter notifier\n");
  
  	ret = register_module_notifier(&ftrace_module_exit_nb);
  	if (ret)
  		pr_warning("Failed to register trace ftrace module exit notifier\n");
  
  	set_ftrace_early_filters();
  
  	return;
   failed:
  	ftrace_disabled = 1;
  }
  
  #else
  
  static struct ftrace_ops global_ops = {
  	.func			= ftrace_stub,
  	.flags			= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
  	INIT_REGEX_LOCK(global_ops)
  };
  
  static int __init ftrace_nodyn_init(void)
  {
  	ftrace_enabled = 1;
  	return 0;
  }
  core_initcall(ftrace_nodyn_init);
  
  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(ops, command)					\
  	({								\
  		int ___ret = __register_ftrace_function(ops);		\
  		if (!___ret)						\
  			(ops)->flags |= FTRACE_OPS_FL_ENABLED;		\
  		___ret;							\
  	})
  # define ftrace_shutdown(ops, command) __unregister_ftrace_function(ops)
  
  # 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, void *regs)
  {
  	return 1;
  }
  
  #endif /* CONFIG_DYNAMIC_FTRACE */
  
  static void
  ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
  			struct ftrace_ops *op, struct pt_regs *regs)
  {
  	if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
  		return;
  
  	/*
  	 * Some of the ops may be dynamically allocated,
  	 * they must be freed after a synchronize_sched().
  	 */
  	preempt_disable_notrace();
  	trace_recursion_set(TRACE_CONTROL_BIT);
  
  	/*
  	 * Control funcs (perf) uses RCU. Only trace if
  	 * RCU is currently active.
  	 */
  	if (!rcu_is_watching())
  		goto out;
  
  	do_for_each_ftrace_op(op, ftrace_control_list) {
  		if (!(op->flags & FTRACE_OPS_FL_STUB) &&
  		    !ftrace_function_local_disabled(op) &&
  		    ftrace_ops_test(op, ip, regs))
  			op->func(ip, parent_ip, op, regs);
  	} while_for_each_ftrace_op(op);
   out:
  	trace_recursion_clear(TRACE_CONTROL_BIT);
  	preempt_enable_notrace();
  }
  
  static struct ftrace_ops control_ops = {
  	.func	= ftrace_ops_control_func,
  	.flags	= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
  	INIT_REGEX_LOCK(control_ops)
  };
  
  static inline void
  __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
  		       struct ftrace_ops *ignored, struct pt_regs *regs)
  {
  	struct ftrace_ops *op;
  	int bit;
  
  	if (function_trace_stop)
  		return;
  
  	bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
  	if (bit < 0)
  		return;
  
  	/*
  	 * Some of the ops may be dynamically allocated,
  	 * they must be freed after a synchronize_sched().
  	 */
  	preempt_disable_notrace();
  	do_for_each_ftrace_op(op, ftrace_ops_list) {
  		if (ftrace_ops_test(op, ip, regs))
  			op->func(ip, parent_ip, op, regs);
  	} while_for_each_ftrace_op(op);
  	preempt_enable_notrace();
  	trace_clear_recursion(bit);
  }
  
  /*
   * Some archs only support passing ip and parent_ip. Even though
   * the list function ignores the op parameter, we do not want any
   * C side effects, where a function is called without the caller
   * sending a third parameter.
   * Archs are to support both the regs and ftrace_ops at the same time.
   * If they support ftrace_ops, it is assumed they support regs.
   * If call backs want to use regs, they must either check for regs
   * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
   * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
   * An architecture can pass partial regs with ftrace_ops and still
   * set the ARCH_SUPPORT_FTARCE_OPS.
   */
  #if ARCH_SUPPORTS_FTRACE_OPS
  static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
  				 struct ftrace_ops *op, struct pt_regs *regs)
  {
  	__ftrace_ops_list_func(ip, parent_ip, NULL, regs);
  }
  #else
  static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
  {
  	__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
  }
  #endif
  
  static void clear_ftrace_swapper(void)
  {
  	struct task_struct *p;
  	int cpu;
  
  	get_online_cpus();
  	for_each_online_cpu(cpu) {
  		p = idle_task(cpu);
  		clear_tsk_trace_trace(p);
  	}
  	put_online_cpus();
  }
  
  static void set_ftrace_swapper(void)
  {
  	struct task_struct *p;
  	int cpu;
  
  	get_online_cpus();
  	for_each_online_cpu(cpu) {
  		p = idle_task(cpu);
  		set_tsk_trace_trace(p);
  	}
  	put_online_cpus();
  }
  
  static void clear_ftrace_pid(struct pid *pid)
  {
  	struct task_struct *p;
  
  	rcu_read_lock();
  	do_each_pid_task(pid, PIDTYPE_PID, p) {
  		clear_tsk_trace_trace(p);
  	} while_each_pid_task(pid, PIDTYPE_PID, p);
  	rcu_read_unlock();
  
  	put_pid(pid);
  }
  
  static void set_ftrace_pid(struct pid *pid)
  {
  	struct task_struct *p;
  
  	rcu_read_lock();
  	do_each_pid_task(pid, PIDTYPE_PID, p) {
  		set_tsk_trace_trace(p);
  	} while_each_pid_task(pid, PIDTYPE_PID, p);
  	rcu_read_unlock();
  }
  
  static void clear_ftrace_pid_task(struct pid *pid)
  {
  	if (pid == ftrace_swapper_pid)
  		clear_ftrace_swapper();
  	else
  		clear_ftrace_pid(pid);
  }
  
  static void set_ftrace_pid_task(struct pid *pid)
  {
  	if (pid == ftrace_swapper_pid)
  		set_ftrace_swapper();
  	else
  		set_ftrace_pid(pid);
  }
  
  static int ftrace_pid_add(int p)
  {
  	struct pid *pid;
  	struct ftrace_pid *fpid;
  	int ret = -EINVAL;
  
  	mutex_lock(&ftrace_lock);
  
  	if (!p)
  		pid = ftrace_swapper_pid;
  	else
  		pid = find_get_pid(p);
  
  	if (!pid)
  		goto out;
  
  	ret = 0;
  
  	list_for_each_entry(fpid, &ftrace_pids, list)
  		if (fpid->pid == pid)
  			goto out_put;
  
  	ret = -ENOMEM;
  
  	fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
  	if (!fpid)
  		goto out_put;
  
  	list_add(&fpid->list, &ftrace_pids);
  	fpid->pid = pid;
  
  	set_ftrace_pid_task(pid);
  
  	ftrace_update_pid_func();
  	ftrace_startup_enable(0);
  
  	mutex_unlock(&ftrace_lock);
  	return 0;
  
  out_put:
  	if (pid != ftrace_swapper_pid)
  		put_pid(pid);
  
  out:
  	mutex_unlock(&ftrace_lock);
  	return ret;
  }
  
  static void ftrace_pid_reset(void)
  {
  	struct ftrace_pid *fpid, *safe;
  
  	mutex_lock(&ftrace_lock);
  	list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
  		struct pid *pid = fpid->pid;
  
  		clear_ftrace_pid_task(pid);
  
  		list_del(&fpid->list);
  		kfree(fpid);
  	}
  
  	ftrace_update_pid_func();
  	ftrace_startup_enable(0);
  
  	mutex_unlock(&ftrace_lock);
  }
  
  static void *fpid_start(struct seq_file *m, loff_t *pos)
  {
  	mutex_lock(&ftrace_lock);
  
  	if (list_empty(&ftrace_pids) && (!*pos))
  		return (void *) 1;
  
  	return seq_list_start(&ftrace_pids, *pos);
  }
  
  static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
  {
  	if (v == (void *)1)
  		return NULL;
  
  	return seq_list_next(v, &ftrace_pids, pos);
  }
  
  static void fpid_stop(struct seq_file *m, void *p)
  {
  	mutex_unlock(&ftrace_lock);
  }
  
  static int fpid_show(struct seq_file *m, void *v)
  {
  	const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
  
  	if (v == (void *)1) {
  		seq_printf(m, "no pid\n");
  		return 0;
  	}
  
  	if (fpid->pid == ftrace_swapper_pid)
  		seq_printf(m, "swapper tasks\n");
  	else
  		seq_printf(m, "%u\n", pid_vnr(fpid->pid));
  
  	return 0;
  }
  
  static const struct seq_operations ftrace_pid_sops = {
  	.start = fpid_start,
  	.next = fpid_next,
  	.stop = fpid_stop,
  	.show = fpid_show,
  };
  
  static int
  ftrace_pid_open(struct inode *inode, struct file *file)
  {
  	int ret = 0;
  
  	if ((file->f_mode & FMODE_WRITE) &&
  	    (file->f_flags & O_TRUNC))
  		ftrace_pid_reset();
  
  	if (file->f_mode & FMODE_READ)
  		ret = seq_open(file, &ftrace_pid_sops);
  
  	return ret;
  }
  
  static ssize_t
  ftrace_pid_write(struct file *filp, const char __user *ubuf,
  		   size_t cnt, loff_t *ppos)
  {
  	char buf[64], *tmp;
  	long val;
  	int ret;
  
  	if (cnt >= sizeof(buf))
  		return -EINVAL;
  
  	if (copy_from_user(&buf, ubuf, cnt))
  		return -EFAULT;
  
  	buf[cnt] = 0;
  
  	/*
  	 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
  	 * to clean the filter quietly.
  	 */
  	tmp = strstrip(buf);
  	if (strlen(tmp) == 0)
  		return 1;
  
  	ret = kstrtol(tmp, 10, &val);
  	if (ret < 0)
  		return ret;
  
  	ret = ftrace_pid_add(val);
  
  	return ret ? ret : cnt;
  }
  
  static int
  ftrace_pid_release(struct inode *inode, struct file *file)
  {
  	if (file->f_mode & FMODE_READ)
  		seq_release(inode, file);
  
  	return 0;
  }
  
  static const struct file_operations ftrace_pid_fops = {
  	.open		= ftrace_pid_open,
  	.write		= ftrace_pid_write,
  	.read		= seq_read,
  	.llseek		= tracing_lseek,
  	.release	= ftrace_pid_release,
  };
  
  static __init int ftrace_init_debugfs(void)
  {
  	struct dentry *d_tracer;
  
  	d_tracer = tracing_init_dentry();
  	if (!d_tracer)
  		return 0;
  
  	ftrace_init_dyn_debugfs(d_tracer);
  
  	trace_create_file("set_ftrace_pid", 0644, d_tracer,
  			    NULL, &ftrace_pid_fops);
  
  	ftrace_profile_debugfs(d_tracer);
  
  	return 0;
  }
  fs_initcall(ftrace_init_debugfs);
  
  /**
   * ftrace_kill - kill ftrace
   *
   * This function should be used by panic code. It stops ftrace
   * but in a not so nice way. If you need to simply kill ftrace
   * from a non-atomic section, use ftrace_kill.
   */
  void ftrace_kill(void)
  {
  	ftrace_disabled = 1;
  	ftrace_enabled = 0;
  	clear_ftrace_function();
  }
  
  /**
   * Test if ftrace is dead or not.
   */
  int ftrace_is_dead(void)
  {
  	return ftrace_disabled;
  }
  
  /**
   * register_ftrace_function - register a function for profiling
   * @ops - ops structure that holds the function for profiling.
   *
   * Register a function to be called by all functions in the
   * kernel.
   *
   * Note: @ops->func and all the functions it calls must be labeled
   *       with "notrace", otherwise it will go into a
   *       recursive loop.
   */
  int register_ftrace_function(struct ftrace_ops *ops)
  {
  	int ret = -1;
  
  	ftrace_ops_init(ops);
  
  	mutex_lock(&ftrace_lock);
  
  	ret = ftrace_startup(ops, 0);
  
  	mutex_unlock(&ftrace_lock);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(register_ftrace_function);
  
  /**
   * unregister_ftrace_function - unregister a function for profiling.
   * @ops - ops structure that holds the function to unregister
   *
   * Unregister a function that was added to be called by ftrace profiling.
   */
  int unregister_ftrace_function(struct ftrace_ops *ops)
  {
  	int ret;
  
  	mutex_lock(&ftrace_lock);
  	ret = ftrace_shutdown(ops, 0);
  	mutex_unlock(&ftrace_lock);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(unregister_ftrace_function);
  
  int
  ftrace_enable_sysctl(struct ctl_table *table, int write,
  		     void __user *buffer, size_t *lenp,
  		     loff_t *ppos)
  {
  	int ret = -ENODEV;
  
  	mutex_lock(&ftrace_lock);
  
  	if (unlikely(ftrace_disabled))
  		goto out;
  
  	ret = proc_dointvec(table, write, buffer, lenp, ppos);
  
  	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
  		goto out;
  
  	last_ftrace_enabled = !!ftrace_enabled;
  
  	if (ftrace_enabled) {
  
  		ftrace_startup_sysctl();
  
  		/* we are starting ftrace again */
  		if (ftrace_ops_list != &ftrace_list_end)
  			update_ftrace_function();
  
  	} else {
  		/* stopping ftrace calls (just send to ftrace_stub) */
  		ftrace_trace_function = ftrace_stub;
  
  		ftrace_shutdown_sysctl();
  	}
  
   out:
  	mutex_unlock(&ftrace_lock);
  	return ret;
  }
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  
  static int ftrace_graph_active;
  static struct notifier_block ftrace_suspend_notifier;
  
  int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
  {
  	return 0;
  }
  
  /* 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 = ftrace_graph_entry_stub;
  static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_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)
  {
  	int i;
  	int ret = 0;
  	unsigned long flags;
  	int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
  	struct task_struct *g, *t;
  
  	for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
  		ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
  					* sizeof(struct ftrace_ret_stack),
  					GFP_KERNEL);
  		if (!ret_stack_list[i]) {
  			start = 0;
  			end = i;
  			ret = -ENOMEM;
  			goto free;
  		}
  	}
  
  	read_lock_irqsave(&tasklist_lock, flags);
  	do_each_thread(g, t) {
  		if (start == end) {
  			ret = -EAGAIN;
  			goto unlock;
  		}
  
  		if (t->ret_stack == NULL) {
  			atomic_set(&t->tracing_graph_pause, 0);
  			atomic_set(&t->trace_overrun, 0);
  			t->curr_ret_stack = -1;
  			/* Make sure the tasks see the -1 first: */
  			smp_wmb();
  			t->ret_stack = ret_stack_list[start++];
  		}
  	} while_each_thread(g, t);
  
  unlock:
  	read_unlock_irqrestore(&tasklist_lock, flags);
  free:
  	for (i = start; i < end; i++)
  		kfree(ret_stack_list[i]);
  	return ret;
  }
  
  static void
  ftrace_graph_probe_sched_switch(void *ignore,
  			struct task_struct *prev, struct task_struct *next)
  {
  	unsigned long long timestamp;
  	int index;
  
  	/*
  	 * Does the user want to count the time a function was asleep.
  	 * If so, do not update the time stamps.
  	 */
  	if (trace_flags & TRACE_ITER_SLEEP_TIME)
  		return;
  
  	timestamp = trace_clock_local();
  
  	prev->ftrace_timestamp = timestamp;
  
  	/* only process tasks that we timestamped */
  	if (!next->ftrace_timestamp)
  		return;
  
  	/*
  	 * Update all the counters in next to make up for the
  	 * time next was sleeping.
  	 */
  	timestamp -= next->ftrace_timestamp;
  
  	for (index = next->curr_ret_stack; index >= 0; index--)
  		next->ret_stack[index].calltime += timestamp;
  }
  
  /* Allocate a return stack for each task */
  static int start_graph_tracing(void)
  {
  	struct ftrace_ret_stack **ret_stack_list;
  	int ret, cpu;
  
  	ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
  				sizeof(struct ftrace_ret_stack *),
  				GFP_KERNEL);
  
  	if (!ret_stack_list)
  		return -ENOMEM;
  
  	/* The cpu_boot init_task->ret_stack will never be freed */
  	for_each_online_cpu(cpu) {
  		if (!idle_task(cpu)->ret_stack)
  			ftrace_graph_init_idle_task(idle_task(cpu), cpu);
  	}
  
  	do {
  		ret = alloc_retstack_tasklist(ret_stack_list);
  	} while (ret == -EAGAIN);
  
  	if (!ret) {
  		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
  		if (ret)
  			pr_info("ftrace_graph: Couldn't activate tracepoint"
  				" probe to kernel_sched_switch\n");
  	}
  
  	kfree(ret_stack_list);
  	return ret;
  }
  
  /*
   * Hibernation protection.
   * The state of the current task is too much unstable during
   * suspend/restore to disk. We want to protect against that.
   */
  static int
  ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
  							void *unused)
  {
  	switch (state) {
  	case PM_HIBERNATION_PREPARE:
  		pause_graph_tracing();
  		break;
  
  	case PM_POST_HIBERNATION:
  		unpause_graph_tracing();
  		break;
  	}
  	return NOTIFY_DONE;
  }
  
  /* Just a place holder for function graph */
  static struct ftrace_ops fgraph_ops __read_mostly = {
  	.func		= ftrace_stub,
  	.flags		= FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_GLOBAL |
  				FTRACE_OPS_FL_RECURSION_SAFE,
  };
  
  static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
  {
  	if (!ftrace_ops_test(&global_ops, trace->func, NULL))
  		return 0;
  	return __ftrace_graph_entry(trace);
  }
  
  /*
   * The function graph tracer should only trace the functions defined
   * by set_ftrace_filter and set_ftrace_notrace. If another function
   * tracer ops is registered, the graph tracer requires testing the
   * function against the global ops, and not just trace any function
   * that any ftrace_ops registered.
   */
  static void update_function_graph_func(void)
  {
  	if (ftrace_ops_list == &ftrace_list_end ||
  	    (ftrace_ops_list == &global_ops &&
  	     global_ops.next == &ftrace_list_end))
  		ftrace_graph_entry = __ftrace_graph_entry;
  	else
  		ftrace_graph_entry = ftrace_graph_entry_test;
  }
  
  int register_ftrace_graph(trace_func_graph_ret_t retfunc,
  			trace_func_graph_ent_t entryfunc)
  {
  	int ret = 0;
  
  	mutex_lock(&ftrace_lock);
  
  	/* we currently allow only one tracer registered at a time */
  	if (ftrace_graph_active) {
  		ret = -EBUSY;
  		goto out;
  	}
  
  	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
  	register_pm_notifier(&ftrace_suspend_notifier);
  
  	ftrace_graph_active++;
  	ret = start_graph_tracing();
  	if (ret) {
  		ftrace_graph_active--;
  		goto out;
  	}
  
  	ftrace_graph_return = retfunc;
  
  	/*
  	 * Update the indirect function to the entryfunc, and the
  	 * function that gets called to the entry_test first. Then
  	 * call the update fgraph entry function to determine if
  	 * the entryfunc should be called directly or not.
  	 */
  	__ftrace_graph_entry = entryfunc;
  	ftrace_graph_entry = ftrace_graph_entry_test;
  	update_function_graph_func();
  
  	ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET);
  
  out:
  	mutex_unlock(&ftrace_lock);
  	return ret;
  }
  
  void unregister_ftrace_graph(void)
  {
  	mutex_lock(&ftrace_lock);
  
  	if (unlikely(!ftrace_graph_active))
  		goto out;
  
  	ftrace_graph_active--;
  	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
  	ftrace_graph_entry = ftrace_graph_entry_stub;
  	__ftrace_graph_entry = ftrace_graph_entry_stub;
  	ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET);
  	unregister_pm_notifier(&ftrace_suspend_notifier);
  	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
  
   out:
  	mutex_unlock(&ftrace_lock);
  }
  
  static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
  
  static void
  graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
  {
  	atomic_set(&t->tracing_graph_pause, 0);
  	atomic_set(&t->trace_overrun, 0);
  	t->ftrace_timestamp = 0;
  	/* make curr_ret_stack visible before we add the ret_stack */
  	smp_wmb();
  	t->ret_stack = ret_stack;
  }
  
  /*
   * Allocate a return stack for the idle task. May be the first
   * time through, or it may be done by CPU hotplug online.
   */
  void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
  {
  	t->curr_ret_stack = -1;
  	/*
  	 * The idle task has no parent, it either has its own
  	 * stack or no stack at all.
  	 */
  	if (t->ret_stack)
  		WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
  
  	if (ftrace_graph_active) {
  		struct ftrace_ret_stack *ret_stack;
  
  		ret_stack = per_cpu(idle_ret_stack, cpu);
  		if (!ret_stack) {
  			ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
  					    * sizeof(struct ftrace_ret_stack),
  					    GFP_KERNEL);
  			if (!ret_stack)
  				return;
  			per_cpu(idle_ret_stack, cpu) = ret_stack;
  		}
  		graph_init_task(t, ret_stack);
  	}
  }
  
  /* Allocate a return stack for newly created task */
  void ftrace_graph_init_task(struct task_struct *t)
  {
  	/* Make sure we do not use the parent ret_stack */
  	t->ret_stack = NULL;
  	t->curr_ret_stack = -1;
  
  	if (ftrace_graph_active) {
  		struct ftrace_ret_stack *ret_stack;
  
  		ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
  				* sizeof(struct ftrace_ret_stack),
  				GFP_KERNEL);
  		if (!ret_stack)
  			return;
  		graph_init_task(t, ret_stack);
  	}
  }
  
  void ftrace_graph_exit_task(struct task_struct *t)
  {
  	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
  
  	t->ret_stack = NULL;
  	/* NULL must become visible to IRQs before we free it: */
  	barrier();
  
  	kfree(ret_stack);
  }
  
  void ftrace_graph_stop(void)
  {
  	ftrace_stop();
  }
  #endif
  