/*
   *  This code maintains a list of active profiling data structures.
   *
   *    Copyright IBM Corp. 2009
   *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
   *
   *    Uses gcc-internal data definitions.
   *    Based on the gcov-kernel patch by:
   *		 Hubertus Franke <frankeh@us.ibm.com>
   *		 Nigel Hinds <nhinds@us.ibm.com>
   *		 Rajan Ravindran <rajancr@us.ibm.com>
   *		 Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
   *		 Paul Larson
   */
  
  #define pr_fmt(fmt)	"gcov: " fmt
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include "gcov.h"

  static int gcov_events_enabled;
  static DEFINE_MUTEX(gcov_lock);
  
  /*
   * __gcov_init is called by gcc-generated constructor code for each object
   * file compiled with -fprofile-arcs.
   */
  void __gcov_init(struct gcov_info *info)
  {
  	static unsigned int gcov_version;
  
  	mutex_lock(&gcov_lock);
  	if (gcov_version == 0) {

  		gcov_version = gcov_info_version(info);

  		/*
  		 * Printing gcc's version magic may prove useful for debugging
  		 * incompatibility reports.
  		 */
  		pr_info("version magic: 0x%x
  ", gcov_version);
  	}
  	/*
  	 * Add new profiling data structure to list and inform event
  	 * listener.
  	 */

  	gcov_info_link(info);

  	if (gcov_events_enabled)
  		gcov_event(GCOV_ADD, info);
  	mutex_unlock(&gcov_lock);
  }
  EXPORT_SYMBOL(__gcov_init);
  
  /*
   * These functions may be referenced by gcc-generated profiling code but serve
   * no function for kernel profiling.
   */
  void __gcov_flush(void)
  {
  	/* Unused. */
  }
  EXPORT_SYMBOL(__gcov_flush);
  
  void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
  {
  	/* Unused. */
  }
  EXPORT_SYMBOL(__gcov_merge_add);
  
  void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
  {
  	/* Unused. */
  }
  EXPORT_SYMBOL(__gcov_merge_single);
  
  void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
  {
  	/* Unused. */
  }
  EXPORT_SYMBOL(__gcov_merge_delta);

  void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
  {
  	/* Unused. */
  }
  EXPORT_SYMBOL(__gcov_merge_ior);

  /**
   * gcov_enable_events - enable event reporting through gcov_event()
   *
   * Turn on reporting of profiling data load/unload-events through the
   * gcov_event() callback. Also replay all previous events once. This function
   * is needed because some events are potentially generated too early for the
   * callback implementation to handle them initially.
   */
  void gcov_enable_events(void)
  {

  	struct gcov_info *info = NULL;

  
  	mutex_lock(&gcov_lock);
  	gcov_events_enabled = 1;

  	/* Perform event callback for previously registered entries. */

  	while ((info = gcov_info_next(info)))

  		gcov_event(GCOV_ADD, info);

  	mutex_unlock(&gcov_lock);
  }
  
  #ifdef CONFIG_MODULES
  static inline int within(void *addr, void *start, unsigned long size)
  {
  	return ((addr >= start) && (addr < start + size));
  }
  
  /* Update list and generate events when modules are unloaded. */
  static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
  				void *data)
  {
  	struct module *mod = data;

  	struct gcov_info *info = NULL;
  	struct gcov_info *prev = NULL;

  
  	if (event != MODULE_STATE_GOING)
  		return NOTIFY_OK;
  	mutex_lock(&gcov_lock);

  	/* Remove entries located in module from linked list. */

  	while ((info = gcov_info_next(info))) {

  		if (within(info, mod->module_core, mod->core_size)) {

  			gcov_info_unlink(prev, info);

  			if (gcov_events_enabled)
  				gcov_event(GCOV_REMOVE, info);
  		} else
  			prev = info;
  	}

  	mutex_unlock(&gcov_lock);
  
  	return NOTIFY_OK;
  }
  
  static struct notifier_block gcov_nb = {
  	.notifier_call	= gcov_module_notifier,
  };
  
  static int __init gcov_init(void)
  {
  	return register_module_notifier(&gcov_nb);
  }
  device_initcall(gcov_init);
  #endif /* CONFIG_MODULES */