libtracing/tracercore.c

   1 /*
   2  * LTT core in-kernel infrastructure.
   3  *
   4  * Copyright 2006 - Mathieu Desnoyers mathieu.desnoyers@polymtl.ca
   5  *
   6  * Distributed under the GPL license
   7  */
   8
   9 #include <linux/ltt-core.h>
  10 #include <linux/percpu.h>
  11 #include <linux/module.h>
  12 #include <linux/debugfs.h>
  13
  14 /* Traces structures */
  15 struct ltt_traces ltt_traces = {
  16         .setup_head = LIST_HEAD_INIT(ltt_traces.setup_head),
  17         .head = LIST_HEAD_INIT(ltt_traces.head),
  18 };
  19 EXPORT_SYMBOL(ltt_traces);
  20
  21 /* Traces list writer locking */
  22 static DEFINE_MUTEX(ltt_traces_mutex);
  23
  24 /* dentry of ltt's root dir */
  25 static struct dentry *ltt_root_dentry;
  26 struct dentry *get_ltt_root(void)
  27 {
  28         if (!ltt_root_dentry) {
  29                 ltt_root_dentry = debugfs_create_dir(LTT_ROOT, NULL);
  30                 if (!ltt_root_dentry)
  31                         printk(KERN_ERR "LTT : create ltt root dir failed\n");
  32         }
  33         return ltt_root_dentry;
  34 }
  35 EXPORT_SYMBOL_GPL(get_ltt_root);
  36
  37 void ltt_lock_traces(void)
  38 {
  39         mutex_lock(&ltt_traces_mutex);
  40 }
  41 EXPORT_SYMBOL_GPL(ltt_lock_traces);
  42
  43 void ltt_unlock_traces(void)
  44 {
  45         mutex_unlock(&ltt_traces_mutex);
  46 }
  47 EXPORT_SYMBOL_GPL(ltt_unlock_traces);
  48
  49 DEFINE_PER_CPU(unsigned int, ltt_nesting);
  50 EXPORT_PER_CPU_SYMBOL(ltt_nesting);
  51
  52 int ltt_run_filter_default(void *trace, uint16_t eID)
  53 {
  54         return 1;
  55 }
  56
  57 /* This function pointer is protected by a trace activation check */
  58 ltt_run_filter_functor ltt_run_filter = ltt_run_filter_default;
  59 EXPORT_SYMBOL_GPL(ltt_run_filter);
  60
  61 void ltt_filter_register(ltt_run_filter_functor func)
  62 {
  63         ltt_run_filter = func;
  64 }
  65 EXPORT_SYMBOL_GPL(ltt_filter_register);
  66
  67 void ltt_filter_unregister(void)
  68 {
  69         ltt_run_filter = ltt_run_filter_default;
  70 }
  71 EXPORT_SYMBOL_GPL(ltt_filter_unregister);