Line data    Source code

       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  *  This code maintains a list of active profiling data structures.
       4             :  *
       5             :  *    Copyright IBM Corp. 2009
       6             :  *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
       7             :  *
       8             :  *    Uses gcc-internal data definitions.
       9             :  *    Based on the gcov-kernel patch by:
      10             :  *               Hubertus Franke <frankeh@us.ibm.com>
      11             :  *               Nigel Hinds <nhinds@us.ibm.com>
      12             :  *               Rajan Ravindran <rajancr@us.ibm.com>
      13             :  *               Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
      14             :  *               Paul Larson
      15             :  */
      16             : 
      17             : #define pr_fmt(fmt)     "gcov: " fmt
      18             : 
      19             : #include <linux/init.h>
      20             : #include <linux/module.h>
      21             : #include <linux/mutex.h>
      22             : #include <linux/sched.h>
      23             : #include "gcov.h"
      24             : 
      25             : int gcov_events_enabled;
      26             : DEFINE_MUTEX(gcov_lock);
      27             : 
      28             : /**
      29             :  * gcov_enable_events - enable event reporting through gcov_event()
      30             :  *
      31             :  * Turn on reporting of profiling data load/unload-events through the
      32             :  * gcov_event() callback. Also replay all previous events once. This function
      33             :  * is needed because some events are potentially generated too early for the
      34             :  * callback implementation to handle them initially.
      35             :  */
      36           1 : void gcov_enable_events(void)
      37             : {
      38           1 :         struct gcov_info *info = NULL;
      39             : 
      40           1 :         mutex_lock(&gcov_lock);
      41           1 :         gcov_events_enabled = 1;
      42             : 
      43             :         /* Perform event callback for previously registered entries. */
      44         956 :         while ((info = gcov_info_next(info))) {
      45         955 :                 gcov_event(GCOV_ADD, info);
      46         955 :                 cond_resched();
      47             :         }
      48             : 
      49           1 :         mutex_unlock(&gcov_lock);
      50           1 : }
      51             : 
      52             : #ifdef CONFIG_MODULES
      53             : /* Update list and generate events when modules are unloaded. */
      54             : static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
      55             :                                 void *data)
      56             : {
      57             :         struct module *mod = data;
      58             :         struct gcov_info *info = NULL;
      59             :         struct gcov_info *prev = NULL;
      60             : 
      61             :         if (event != MODULE_STATE_GOING)
      62             :                 return NOTIFY_OK;
      63             :         mutex_lock(&gcov_lock);
      64             : 
      65             :         /* Remove entries located in module from linked list. */
      66             :         while ((info = gcov_info_next(info))) {
      67             :                 if (gcov_info_within_module(info, mod)) {
      68             :                         gcov_info_unlink(prev, info);
      69             :                         if (gcov_events_enabled)
      70             :                                 gcov_event(GCOV_REMOVE, info);
      71             :                 } else
      72             :                         prev = info;
      73             :         }
      74             : 
      75             :         mutex_unlock(&gcov_lock);
      76             : 
      77             :         return NOTIFY_OK;
      78             : }
      79             : 
      80             : static struct notifier_block gcov_nb = {
      81             :         .notifier_call  = gcov_module_notifier,
      82             : };
      83             : 
      84             : static int __init gcov_init(void)
      85             : {
      86             :         return register_module_notifier(&gcov_nb);
      87             : }
      88             : device_initcall(gcov_init);
      89             : #endif /* CONFIG_MODULES */